Briefly describe the two major divisions of the order Diptera characterized by form and give an example for each statistics of erectile dysfunction in us vardenafil 10mg low price. Cluster flies (along with houseflies erectile dysfunction weed order vardenafil 10 mg visa, face flies erectile dysfunction for young men cheap 10 mg vardenafil fast delivery, some blowflies erectile dysfunction gif order 20mg vardenafil mastercard, and flesh flies) are referred to as "attic flies" because they often overwinter as adults in unused attics erectile dysfunction caused by radical prostatectomy generic vardenafil 10mg otc. List at least three pest management procedures for controlling attic/cluster flies erectile dysfunction fact sheet order vardenafil 20mg mastercard. List at least three pest management procedures for fruit fly or Drosphila infestations erectile dysfunction medications for sale 20mg vardenafil overnight delivery. Describe a pest management scenario for house flies/blowflies in which you inspect the area around the structure erectile dysfunction treatment ottawa cheap vardenafil 20 mg line, recommend sanitation and exclusion methods, and apply a pesticide. Pesticide application alone, without proper sanitation, will be enough to control fly pests. Knowledge of the behavior of the various Hymenoptera is essential for their management. Effective communication with frightened or, at best, fearful clients is an important skill technicians must develop. The insects most beneficial to humans are found in the large insect order Hymenoptera. Not only are the bees and many of their relatives pollinators of flowering plants, including fruits and vegetables, but thousands of species of small wasps are parasites of pest insects. Without these parasites that limit the growth of insect populations, pests would overtake most crops. Although they are sometimes a danger to humans, yellow jackets, hornets, and wasps also serve our interests because they feed their young largely on flies and caterpillars. They live in colonies with a caste system or a division of labor and overlapping generations-all offspring of one individual reproductive. Some of these colonies persist for many years (ants, honeybees); others, such as stinging wasps, start a new colony each year. The common paper wasp, with its umbrella-shaped nest or single comb, best demonstrates the basic building pattern of a colony. They develop adult systems, then shed their pupal skins, chew through their silk cell cap, pump out their wings, and take their place as worker assistants to their mother. They do not eat the protein (insect) food they gather for the larvae but get their energy from flower nectar. The new males and females mate with those of other colonies, and the fertilized females find hiding places under tree bark or in logs and wait out the winter until they can begin their new colony in the spring. Control and Management of Paper Wasps Paper wasp nests are often found near doorways and other human activity areas without occupants being stung. When attracted to fallen ripe fruit, these wasps sting people who venture into the same area. Colonies in trees, hollow fenceposts, and other protected places are not as easy to control as those on structures. The paper wasp queen, as is true of other vespids, is the lone female reproductive that overwinters. She begins her nest by attaching a thick paper strand to an overhanging structure. She then builds hollow paper cells by chewing wood or plant fibers (cellulose) mixed with water and shaped with her mouthparts. Pesticide Application s Use pressurized sprays that propel spray for 8 to 12 feet or use aerosols on extension poles especially manufactured for aerosol cans. When a half dozen cells or so are hanging together, the queen lays an egg near the bottom of each one. The little white grubs that hatch from the egg glue their rear ends in the cells and begin receiving nourishment in the form of chewed-up bits of caterpillars provided by their mother. When they grow large enough to fill the cell cavity, they break the glued spot and hang on head down. She develops smaller daughter workers and, later on, reproductives just as the paper wasps do, but the nest structure is not the same. Some yellow jacket nests hang in trees and shrubs, and some are developed underground. Two of these yellow jackets are common: the aerial yellow jacket, Dolichovespula arenaria, and the bald-faced hornet, Dolichovespula maculata. The aerial yellow jacket is found in Canada and in the western and eastern United States (but not in the central and southern states). This species begins its nest in March or April and is finished and no longer active by the end of July. Their nests, usually attached to building overhangs, are smaller and more round than those of other species. The bald-faced hornet is larger than the other yellow jackets and is black and white, not black and yellow. It lives along the West Coast, across Canada, and in all of the states in the eastern half of the country. On warm spring days, the large aerial nesting queen, like the paper wasp, develops a small comb with a dozen or so cells, but she encloses it in a round, gray, paper envelope. The daughter workers later take over the nest duties, and by midsummer, when the worker population is growing and food is plentiful, the nest is expanded to full size. A full-sized bald-faced hornet nest consists not of a single umbrella comb like the paper wasp nest, but of four to six wide circular combs, one hanging below another and all enclosed in an oval paper envelope consisting of several insulating layers. Bald-faced hornets not only gather flies but are large enough to kill and use other species of yellow jackets for larval food. Although aerial colonies can have 400 to 700 workers at one time, their food-gathering habits do not routinely bring them in contact with humans. Underground Nesters the stinging wasp, often identified as a yellow jacket, is black and yellow. They begin their nests like the aerial nesters-with an enveloped small comb made of wood fiber paper. Only these nests are started in soil depressions, rodent burrows, or in any small hole in the ground that will give protection until workers can develop. Several species of Vespula make their nests in building wall voids, attics, hollow trees, and other enclosed spaces, as well as in the ground. Both Aerial and Ground Nesters Of the thirteen species in North America, only a few require management. Foraging workers capture insects for their larvae and nectar and other sweet carbohydrates for themselves where they can find it them. One can easily see that these habits put a large number of foraging stinging insects into close association with large populations of humans. Common in higher elevations, it nests in shady evergreen forests around parks and camps in the western mountains and the eastern Appalachians. Yellow jackets are sometimes responsible for injections of anaerobic bacteria (organisms that cause blood poisoning). When yellow jackets frequent wet manure and sewage they pick up the bacteria on their abdomens and stingers. Eastern Yellow Jacket (Vespula maculifrons) this common ground-nesting yellow jacket is distributed over the eastern half of the United States. Workers are slightly smaller than most other yellow jackets, but colony size can number around 5,000 or more individuals. Where the nest has not been located, look in shrubbery, hedges, and low tree limbs for the bald-faced hornet. Soil nests are often located under shrubs, logs, piles of rocks and other protected sites. Entrance holes in structures are usually marked by fast flying workers entering and leaving. German Yellow Jacket (Vespula germanica) In Europe, German yellow jacket nests are subterranean, but in North America the vast majority of reported nests are in structures. This yellow jacket is distributed throughout the northeastern quarter of the United States. Nests in attics and wall voids are large, and workers can chew through ceilings and walls into adjacent rooms. The nest and nest envelope of this yellow jacket are made of strong, light gray paper. Colonies of this yellow jacket may be active in protected voids into November and December when outside temperatures are not severe. Section 3: Chapter 12 110 General Pest Management s Empty cans and dumpsters daily prior to periods of heavy human traffic at zoos, amusement parks, fairs, and sporting events. Wall Voids s Approach the entrance hole cautiously; stay out of pensing stations, and locate trashcans away from food-dispensing windows. Observe whether yellow jackets enter- ing the nest go straight in or to one side or the other. More often than not, because of traditional work schedules, treatment will be scheduled for the daytime. Unless these insects can hold on with their tarsal claws, they cannot get the leverage to sting. Bee suits are made with smooth rip-stop nylon that does not allow wasps and bees to hold on. Wrist and ankle cuffs must be taped or tied to keep the insects out of sleeves and pant legs. Spraying trashcans and the outside of food stands will reduce or repel yellow jackets at sporting events. Follow-up On-going monitoring throughout the active yellow jacket season is essential when a pest management program is in place at parks, recreational areas, zoos, and other outdoor activity areas. Honeybees are highly social insects and communicate with one another, relaying direction and distance of nectar and pollen sources. Bees make combs of waxen cells placed side by side that provide spaces to rear young and store honey. The bee colony lives on the stored honey throughout winter and, therefore, can persist for years. When colony populations are high, the queen may move part of the colony to new harborage. Bees swarm at this time, usually finding hollow trees to begin their new colony, but they occasionally work their way into building wall voids. Application s Insert the plastic extension tube from a pressurized liquid spray or aerosol generator in the entrance hole; release the pesticide for 10 to 30 seconds. If the pressurized liquid spray includes chemicals that rapidly lower nest temperature (freeze products), be aware that it will damage shrubbery. Returning yellow jackets cue on entrance holes using surrounding landmarks and seeing the shadowed opening. General Pest Management 111 Section 3: Chapter 12 When a bee colony is found in a building wall, it must be killed. Killing can be accomplished in the same way as killing yellow jackets in wall voids. Listen to the bee noise from inside rooms to locate the exact position of the nest in the wall to assure that the whole colony is treated. If the nest is not removed, the wax combs-normally cooled by the bees-will melt and allow honey to flow down through the walls. After the colony is killed, the entrance hole should be caulked or repaired to prevent further bee infestation. The most common carpenter bee, Xylocopa virginica, is distributed throughout the eastern half of North America. Superficially, it resembles yellow and black female bumblebees, which are social and more closely related to honeybees. Western carpenter bees are also large, shiny, sometimes metallic, and are shaped like bumblebees. Carpenter bees bore in wood and make a long tunnel provisioned with pollen and eggs. They prefer to enter unpainted wood and commonly tunnel in redwood and unpainted deck timbers. They will also go into painted wood, especially if any type of start hole is present. Males hover around the tunnel entrance while the female provisions the nest and lays eggs. Males dart at intruders belligerently but they can do no harm-they have no stingers. New adults emerge after the middle of summer and can be seen feeding at flowers until they seek overwintering sites, sometimes in the tunnels. Control and Management of Carpenter Bees Carpenter bees drill into the end grain of structural wood or into the face of a wooden member, then turn and tunnel with the grain. A dusted plug stops new adults that otherwise would emerge through shallow caulking. Caution should be taken, especially if technicians are working on ladders and if they are not experienced with these rather harmless bees. Many mud daubers paralyze spiders to provision mud cells built to enclose eggs, larvae, and pupae. The mud dauber wasps are slender, shiny black or brown, orange or yellow, with black markings. Mud daubers place their mud nests in protected places such as electric motors, sheds, attics, against house siding, and under porch ceilings. So many wasps congregate at the same site to construct the mud nests that later removal of the nests and repainting is often expensive. General Pest Management 113 Mud daubers are killed easily with aerosol contact sprays. Nesting should be discouraged on porticos and high porches of historically important buildings. When there is undue worry about these huge wasps, open soil burrows can be dusted individually. Hymenoptera undergo complete metamorphosis and thousands of species are parasites of other insects. In many instances, they are encouraged, protected, or reared and released for their pest suppression qualities. Many species of Hymenoptera are social, including stinging insects such as yellow jack- ets, paper wasps, and honeybees as well as the ants. Stinging social insects (with the single queen) can be very aggressive because there are many workers that can be used to protect the hive at the expense of their life. Stinging non-social Hymenoptera such as mud daubers, cicada killers, and carpenter bees tend to be non-aggressive and are usually single fertile females or queens that do not have a colony or a protective caste with individuals that can be expended. Nest is four to six wide circular combs, one hanging below another; enclosed in an oval paper envelope. Eastern yellow jacket German yellow jacket Honeybee Paper wasp Write the answers to the following questions and then check your answers with those in Appendix A in the back of this manual. Describe the procedure for applying pesticides for controlling aerial-nesting yellow jackets. Clients should be informed that it is not possible for them to contract blood poisoning from the stings of yellow jackets. The fangs are used to bite prey (mostly other arthropods) and inject poison to immobilize it. Two short, leg-like mouthparts help hold the paralyzed prey while the chelicerae work back and forth, tearing the exoskeleton. Spiders keep working their prey in this way until all the juices are gone and the remainder is a dry, crumbled lump. The anal opening is located near the end of the abdomen, and close by are some short appendages called the spinnerets. All spiders produce silk, and they use silk in more interesting ways than most other silk producers. Most spiders feed out a dragline wherever they walk and never fall off edges without catching themselves. Two spiders are considered dangerous to humans in the United States: the black widow and the brown recluse. Spiders are valuable for their role as predators and natural regulators of insect populations. But some spiders when found in or around structures, are considered pests, especially those that are poisonous. Fear of spiders prompts many people to insist on their control even if the spider represents no significant threat or problem. Female black widows have large, round, shiny black abdomens usually decorated with two touching red triangles on the belly, the so-called "hourglass. Male black widows are small, white, and streaked with yellow and red; they are not dangerous. Control and Management of the Black Widow Spider Habitat Alteration Eliminate harborage sites carefully. Pesticide Application Pesticides must come directly into contact with the spiders because they do not leave their webs or wander after they have become established in the summer. A control method found in nature is provided by mud dauber wasps (see Chapter 12). They paralyze spiders and store them in their mud cells for their larvae to devour. It ranges from central Texas north to Oklahoma, Kansas, and Iowa, and south through Illinois, North and South Carolina, northwestern Georgia, and Alabama, with a few collections in adjacent states and where they have been transported in luggage and household furnishings. Other species of recluse spiders live in the Southwest, particularly in desert areas. This spider lives outdoors in the southern part of its range and primarily indoors throughout the rest of its distribution. A dark fiddleshaped mark is obvious on the cephalothorax-the broad base of the fiddle begins at the eyes and the narrow fiddle neck ends just above the attachment of the abdomen.
True Senna (Senna). Vardenafil.
Hemorrhoids, irritable bowel disease, losing weight, and other conditions.
Other complications erectile dysfunction generic drugs discount 20mg vardenafil with visa, as previously defined impotence 40 year old discount vardenafil 20 mg free shipping, did occur but were not statistically significant between groups erectile dysfunction viagra cialis levitra cheap vardenafil 20 mg with visa. Potential confounding factors new erectile dysfunction drugs 2013 generic 10 mg vardenafil amex, including age impotence marriage vardenafil 20mg, gender erectile dysfunction yohimbe buy vardenafil 20mg amex, smoking erectile dysfunction yoga exercises discount 10mg vardenafil with amex, diabetes erectile dysfunction treatment in lucknow vardenafil 10mg generic, compartment syndrome and open fracture status were analyzed to see if there were any betweengroup differences that could be attributable to these underlying comorbidities. Gender was not found to impact subsidence (p = 75 Post-surgical subsidence and complications were assessed as primary and secondary outcomes of this study, respectively. Complications were defined as negative outcomes resulting in surgical intervention that could potentially be attributed to the bone graft or bone graft substitute. Included in this outcome measure were infections, which were defined as any peri- or intra-articular infection that, again, required operative intervention (superficial wound infection, septic arthritis, osteomyelitis, etc. Individual complications are detailed by graft type and Schatzker class in Table 3. Experimental methods to assess fixation were modeled after previous studies of subsidence in depressed tibial plateau fractures. Measurements were taken from the intact articular surface to the surface of the depressed fragment (Figure 2). Measurements were taken immediately postoperatively, and again at a minimum of six months. The difference between the measurement at the time of surgery and at six months was calculated and used to determine subsidence. A distance of 2 mm or greater between the surfaces was classified as positive subsidence. The right pane also illustrates the landmarks used for radiographic determination of subsidence. Between the allograft, calcium phosphate and Plexur M groups, the number of smokers was 10, four, and seven respectively and the number of diabetics was one, one, and one. Other complications leading to re-operation noted in the Plexur M group included two cases of arthrofibrosis, one 76 case of osteomyelitis, and one case of aseptic knee pain (Table 3). Discussion Patients with depressed tibial plateau fractures treated with Plexur M were found to have a lower incidence of subsidence than patients treated with allograft and an equal rate to those treated with calcium phosphate bone graft substi- Temple University Journal of Orthopaedic Surgery & Sports Medicine, Spring 2013 tute. Patients treated with Plexur M were found to have a lower incidence of re-operation than patients treated with allograft but a higher rate than those treated with calcium phosphate (Table 2). Plexur M had the lowest infection rate (8%) of all the groups, though this was not statistically significant when pair-wise group comparisons were performed for overall complication rate, as noted in the results above. In general, the relatively high incidence of infection in this study was somewhat higher than expected. Many of those patients had radiographs done elsewhere during follow-up due to insurance restrictions, or were not seen in follow-up long enough for meeting the sixmonth requirement. It could be speculated that whereas patients who did well early in their postoperative course did not continue to follow up, patients with infections required prolonged follow-up and multiple radiographs. There were two cases of arthrofibrosis associated with the use of Plexur M bone graft substitute. While there is not enough data to support or refute the association of increased peri-articular scarring with the use of Plexur M bone graft, further studies are needed to elucidate the significance this finding. Number of Cases (Percentage) with Either Subsidence Greater than 2 mm or a Complication (as Defined in the Text) Divided by the Total Number of Cases in Each Group Allograft Calcium Phosphate Plexur M Subsidence 4/17 (24%) 2/13 (15%) 2/13 (15%) Complication 7/17 (41%) 4/13 (31%) 5/13 (38%) Infections 6/17 (35%) 3/13 (23%) 1/13 (8%)0 Infections requiring operative intervention are listed here as a subclass of overall complications. Infection and subsidence rates in this study were compared with available literature for the use of allograft and calcium phosphate bone substitutes. Quoted infection rates for calcium phosphate and allograft from a recent metaanalysis are 3% and 9%, respectively. It is not associated with a statistically significant higher incidence of subsidence or rate of other complications including infection or reoperation when compared to allograft and calcium phosphate. The material properties of Plexur M are arguably preferable to calcium phosphate, synthetic graft substitutes and certain types of allograft because of its moldability, machinability, and set-time. It also avoids the complications of autografts such as donor-site pain or infection, as well as the high incidence sterile drainage that is reported with calcium sulfate grafts, thus making it a desirable material to use in the fixation of tibial plateau fractures. The minimum acceptable followup period of six months is also relatively short and inconsistent among the analyzed patients. Summary of Complications and Associated Interventions by Graft and Fracture Type Graft Type Allograft Case No. Calcium phosphate substitutes were used with greatest frequency in the middle of the study period. This is an unintended consequence of the retrospective design of this studyandpurelyreflectsthechoicesmadebythesurgeonat the time the patients were treated. Some error was noted due to slight variation in the angulation and rotation of the radiographs between immediate postop and follow-up x-rays. In order to account for this variation and any error in calculating the pixel to millimeter conversion for radiograph reading of subsidence, subsidence measurements less that 2 mm were not considered, similar to previously reported studies. Larger prospective studies with longer, more consistent follow-up are needed to reliably compare Plexur M with its alternatives and to further delineate the risk factors associated with its use. Bone Grafts and Bone Graft Substitutes in Orthopaedic Trauma Surgery: A Critical Analysis. Fixation of tibial plateau fractures with synthetic bone graft versus natural bone graft: a comparison study. Comparison of Autogenous Bone Graft and Endothermic Calcium Phosphate Cement for Defect Augmentation in Tibial Plateau Fractures: A Multicenter, Prospective, Randomized Study. Clinical assessment of calcium phosphate cement to treat tibial plateau fractures. Use of calcium-based demineralized bone matrix/allograft for nonunions and posttraumatic reconstruction of the appendicular skeleton: preliminary results and complications. Weight bearing-induced displacement and migration over time of fracture fragments following split depression fractures of the lateral tibial plateau: a case series with radiostereometric analysis. Minimal internal fixation and calciumphosphate cement in the treatment of fractures of the tibial plateau: a pilot study. It is felt to help improve cartilage repair, range of motion, and clearance of hemarthrosis. Synopsis this article presents a review of the basic science and current research that exists on the use of continuous passive motion therapy following surgery for an intraarticular fracture. This information will be useful for surgeons in the postoperative management of intra-articular fractures in determining the best course of treatment to reduce complications and facilitate quicker recovery. Improved cartilage repair seen with continuous passive motion from animal studies (from Salter et al. First index of healing: the nature of the reparative tissue at three weeks in the 36 defects in each of the three series in adult animals. The bars depict the percentages of the 36 defects in each series that exhibited predominantly hyaline cartilage, incompletely differentiated mesenchymal tissue, and fibrous tissue. Much of the clinical research focuses on the efficacy of this treatment in increasing range of motion and decreasing hospitalization time and post-operative complications following total knee arthroplasty when compared to a regimen focused on physical therapy alone. Many articular fractures, such as tibial plateau fractures, can develop stiffness as a sequelae. These early studies provided evidence of the harmful effects of immobilization which caused deterioration and articular cartilage loss in animal models. Fibrocartilage replaced the articular cartilage, and adhesions developed after immobilization, and after 30 days of immobilization, the cartilage damage could not be reversed like it could be with changes seen in soft tissue. However, this damage could be prevented if immobilization was limited and early exercise was emphasized. He found that the new therapy stimulated healing of the articular cartilage and led to faster and better 80 healing when compared to both immobilization and limited active motion. In this retrospective study, he observed the effects of continuous passive motion for various joint injuries of the hip, knee, ankle, elbow and finger. The researchers then tested the collagen composition of the tendons and the mechanical properties. The thickness of the dissected tendons was measured with a digital micrometer and the mechanical strength by a servocontrolled electromechanical materials testing system. In addition, samples of the tendons were analyzed Temple University Journal of Orthopaedic Surgery & Sports Medicine, Spring 2013 for hydroxyproline content. While the cross-sectional area of control and experimental tendons were similar, averaging 0. Overall, the study found the control tendons, as expected, were the strongest of the three while the tendons coming from the immobilized limbs the weakest. Evaluating joint stiffness specifically, Namba found that at three weeks, the immobilized joint was 2. In this experiment, van Royen used rabbits as his animal models and made skin incisions around the patella and into the knee joint. After three weeks of treatment, van Royen collected samples from the healing wound to observe the collagen organization and test the strength. In terms of swelling, the 24-hour group was the only to show any benefit, though the decrease was not significant. After treatment, the rabbits were allowed normal cage activity for an additional five weeks before being evaluated. Shimizu and his colleagues examined mobility, histological features, and the extent of cartilage repair. These parameters worked out to the same number of cycles per day, but at different frequencies. After harvesting the tendons, the gliding function and 82 strength of the tendons were evaluated at three weeks and six weeks. While the function of the tendons was the same for both groups, the tendon strength of the higher frequency group was significantly greater. In his experiment using rabbit models, seven of the 16 received labeled erythrocyte injections into their knees and were scanned that day and subsequently on days one, two, three, four, and seven. After the injections, one knee was immobilized while the other underwent continuous passive motion therapy continuously for seven days. After seven days of treatment, the knee joints of the rabbits were dissected and examined. The authors explained this difference by postulating that during the continuous passive motion treatment, the intraarticular pressure in the joint is raised and lowered creating a pumping effect that aids in clearance. After taking pressure measurements at full extension and flexion for three complete cycles for 90 minutes, the researchers found that the pressure was the most at the extremesofjointflexionandextension. In this section, we will review the available clinical literature in an attempt to address this. An Example of the Benefits of Early Motion: Tibial Plateau Fractures Tibial plateau fractures represent a periarticular fracture group for which surgery is frequently done, and early motion is typically recommended. While the earlier studies demonstrated benefits for early motion, certain risks such as loss of fracture reduction, failure of internal fixation and compromised healing remained. Dividing patients into groups based on the amount of time they spent immobilized, Gausewitz and colleagues measured overall outcomebyanalyzingkneeflexion,lossoffracturereduction, hospital length of stay and ligamentous laxity. However, patients treated surgically with open reduction and internal fixation developed stiffness after only two weeks of immobilization. While the range of motion measurements were not statistically significant, after two to six weeks of immobilization, fourofthe13patientshadflexionoflessthan105degrees and three had flexion contractures in comparison to the immediatemotiongroup,whichhadonlyoneflexioncontractureandonepatientwithlessthan105degreesflexion. The 23 patients with less than two weeks of immobilization stayed an average of 18. These values could be a slight misrepresentation of drawbacks to the treatment, however, since the longer stay of the patients with earlier mobilization was often due to the use of traction and a cast brace in comparison with patients who were simply discharged in a cast. The primary impact of the study was to highlight the benefits of early mobilization for surgically-treated fractures in recovering and maintaining range of motion. The bars represent the percentages of injected 111In-labelled erythrocytes that remained trapped in the synovium after seven days. Treatment by continuous passive motion decreased this trapping by approximately 50%. Temple University Journal of Orthopaedic Surgery & Sports Medicine, Spring 2013 Figure 3. Patients were reported to have a satisfactory outcome if they achieved a range of motion of at least 90 degrees flexion, a lack of extension of less than 10 degrees and had returned to full activity with occasional mild pain or ache. He found no difference in outcome in patients who started knee movement in the first two weeks compared to those who started after. However, the authors also recognized that if motion was started by the first or second day of recovery rather than simply within the first two weeks, the results might have been more favorable for early motion. In addition, the assessment of satisfactory versus unsatisfactory result was done three years after the injury and no intermediate assessments were included. Therefore, the possibility existed that some more significant differences between the early mobilization group and the group immobilized for more than two weeks could have been observed. However, with the focus of the study not being on post-operative treatments, the patients were not further divided up or analyzed based on these various treatments specifically. Overall, the authors found that 35 of the 43 had excellent results, with bicondylar fractures presenting the most difficulties. Patients who experienced this type of fracture were found to have an 18 degree decrease in range of motion in comparison to other patients. Interestingly, 10 of the 15 patients were in an immobilizer for more than three weeks. In addition, other patients treated postoperatively with an immobilizer for more than three weeks also experienced a decreased mean range of motion, measuring 14 degrees lower than those in an immobilizer for a shorter time period. In summary, Lachiewicz demonstrates preliminary support for the use of early continuous passive motion in the treatment of tibial plateau fractures. Gaston and his colleagues tested joint movement and muscle function at three, six, and 12 months. At 12 months, only 14% had regained normal Temple University Journal of Orthopaedic Surgery & Sports Medicine, Spring 2013 quadriceps muscle strength while 30% had normal hamstring muscle strength. Allthepatientsunderwentstandard physical therapy treatment for 12 weeks after surgery. The study outlined the slow recovery process after fractures of the tibial plateau. Whereas 82% of the patients had achieved 100degreesofkneeflexion,21%stillhadextensiondeficits greater than five degrees, and this deficit was especially pronounced in patients over 40 years of age. The study showed a significant decrease in activity due to knee complaints in the first two to three years following the injury; however, at three to six years following injury, these scores had increased to show good function and a return to pre-injury activity levels. This trend reversed itself after six years of follow-up though with patients again deteriorating due to an increase in arthritis. In contrast to the previous study which found age predicted a worse outcome, this study, which relied more on patient selfevaluation, found that the younger patients felt more impaired by the injury. The results from the previous two studies above highlight the long recovery process that patients with tibial plateau fractures face, and the lack of consensus on post-operative treatment between the two further supports the need for more directed research. Summary Continuous passive motion therapy clearly has some basic science and animal data to support its use in the management of articular cartilage lesions, which can be extrapolated clinically to the treatment of articular fractures. The goals in these cases are not to improve articular cartilage repair, of course, but to essentially improve range of motion, and results have been mixed. The effectiveness of continuous passive motion on range of motion, pain and muscle strength following rotator cuff repair: a systematic review. The efficacy of continuous passive motion in the rehabilitation of anterior cruciate ligament reconstructions. The biological effect of continuous passive motion on the healing of full-thickness defects in articular cartilage. The effect of continuous passive motion on the clearance of a hemarthrosis from a synovial joint: an experimental investigation in the rabbit. The effect of the volume of effusion, joint position and continuous passive motion on intraarticular pressure in the rabbit knee. The effect of continuous passive motion duration and increment on range of motion in total knee arthroplasty patients. Exercise combined with continuous passive motion or slider board therapy compared with exercise only: a randomized controlled trial of patients following total knee arthroplasty. Efficacy of continuous passive motion following total knee arthroplasty: a metaanalysis. Continuous passive motion in the prevention of deep-vein thrombosis: a randomised comparison in trauma patients. Effects of immobilization and exercise on articular cartilage - a review of literature. Clinical application of basic research on continuous passive motion for disorders and injuries of synovial joints: a preliminary report of a feasibility study. Effects of short-term immobilization versus continuous passive motion on the biomechanical and biochemical properties of the rabbit tendon. A comparison of the effects of immobilization and continuous passive motion on surgical wound healing in mature rabbits. The induction of neochondrogenesis in free intra-articularperiostealautograftsundertheinfluenceofcontinuous passive motion. The effects of postoperative continuous passive motion on peripheral nerve repair and regeneration. Passive motion: the dose effects on joint stiffness, muscle mass, bone density, and regional swelling. Experimental study on the repair of full thickness articular cartilage defects: effects of varying periods of continuous passive motion, cage activity, and immobilization. The effects of frequency and duration of controlled passive mobilization on tendon healing. A comparison of 2 continuous passive motion protocols after total knee arthroplasty: a controlled and randomized study. Effectiveness of continuous passive motion and conventional physical therapy after total knee arthroplasty: a randomized clinical trial. Factorsinfluencingtheresultsofopenreduction and internal fixation of tibial plateau fractures. A simple modified arthroscopic procedure for fixation of displaced tibial eminence fractures.
Twenty five of the external fixators were applied to treat factures in the upper extremity erectile dysfunction images purchase vardenafil 20mg on-line, while 50 were applied to the lower extremity erectile dysfunction new drug purchase 10mg vardenafil otc. The most common causes of injury were falls erectile dysfunction doctor milwaukee generic vardenafil 10mg with amex, followed by gunshot wounds and pedestrian-versus-auto accidents impotence young male cheap vardenafil 20mg on line. Of those who developed complications erectile dysfunction and heart disease discount vardenafil 10mg with mastercard, the average number of complications Temple University Journal of Orthopaedic Surgery & Sports Medicine erectile dysfunction medication natural buy generic vardenafil 10mg on-line, Spring 2013 was 2 impotence mayo buy 10 mg vardenafil free shipping. The most commonly recorded complications were heterotopic ossification (16 cases) erectile dysfunction over the counter medications discount vardenafil 20 mg otc, nonunion (15 cases), neurologic deficit (14 cases), tissue necrosis (11 cases), and pin tract infection (nine cases). Overall Complications Complication Any complication Heterotopic ossification Nonunion Neurologic deficit Tissue necrosis Pin tract infection Number of Cases 59 16 15 14 11 9 Average Per Case 2. Specifically, for each additional comorbidity that a patient had, the risk of an increased number of complications developing within 90 days of application of external fixator increased by 1. Furthermore, the number of complications that a patient develops at any time increased by an average of 0. While only three patients developed iatrogenic fractures, this complication was correlated with two specific comorbidities. Patients with a history of osteomyelitis were almost 37 times more likely to develop iatrogenic fractures than those without a history of osteomyelitis (odds ratio estimate 36. Similarly, patients with a history of sarcoidosis were almost 140 times more likely to develop iatrogenic fracture than those without a history of sarcoidosis (odds ratio estimate 139. Sarcoidosis history was also correlated with an increased incidence of pin tract infection (odds ratio estimate 18. A history of injury in the affected limb was correlated with purulent pin site drainage, with an estimated odds ratio of 16. Discussion Previous studies have shown very high complication rates associated with external fixation, and our study confirms that complications are quite common with this treatment modality. Regardless of what medical conditions a patient has, more comorbid conditions may lead to more complications after external fixation. If a patient has significant comorbidities, perhaps an additional treatment modality would be better indicated. Our study indicates that sarcoidosis, osteomyelitis, and previous injury in the fractured limb may be problematic comorbid conditions for external fixation since they were associated with significant complication rates. This may be explained by the idea that osteomyelitis and other previous bone injuries cause weakened bone tissue that predispose it to fracture or infection when an external fixator is applied. Similarly,thesystemicinflammationassociatedwithsarcoidosis may predispose bones to structural damage and infection upon placement of an external fixator. Further research regarding the mechanisms by which these conditions may lead to external fixation complications is needed. Because so many variables were examined with a small number of cases, there may be limitations on the reproducibility of statistical outcomes. For instance, only three patients had comorbid sarcoidosis and only two had history of osteomyelitis, so the calculated odds ratio estimates of these comorbidities associated with specific complications may be overestimates of their true associations. Additionally, all information was collected from electronic medical records, so errors in documentation may have occurred. Future studies, particularly of a prospective design, are warranted in order to more accurately gauge the risk factors of external fixation complications and determine causality. Conclusion According to our study, having multiple co-morbidities at the time of external fixator application may be correlated with higher rates of complications. Medical conditions of particular concern include osteomyelitis, sarcoidosis, and previous injury in the limb undergoing external fixation. Further research is needed to assess these risk factors and complications in more detail. Risk Factors for Complications Variable Number of comorbidities Number of comorbidities Osteomyelitis history Sarcoidosis Sarcoidosis Sarcoidosis Prior injury Outcome Total number of complications Number of complications within 90 days Iatrogenic fracture Iatrogenic fracture Pin tract infection Tissue necrosis Purulent pin site drainage Odds Ratio Estimate 1. Temporary external fixation for the management of complex intra- and periarticular fractures of the lower extremity. Lumbopelvic stabilization with external fixator in a patient with lumbosacral agenesis. Complication rate and pitfalls of temporary bridging external fixator in periarticular communited fractures. Prevention and management of complications arising from external fixation pin sites. Failure of reduction with an external fixator in the management of injuries of the pelvic ring. Intramedullary versus extramedullary fixation for subtrochanteric femur fractures. Deep peroneal nerve injury following external fixation of the ankle: Case report and anatomic study. Radial nerve disruption following application of a hinged elbow external fixator: A report of three cases. Complications encountered while using thin-wire-hybrid-external fixation modular frames for fracture fixation. A retrospective clinical analysis and possible support for "damage control orthopaedic surgery. Fat embolism syndrome following lower limb fracture despite rapid external fixation. External fixation and pseudoaneurysm: Report of a case related to tibial lengthening. Indications, alternatives, and complications of external fixation about the elbow. Orthofix external fixation of distal radius fractures: Complications associated with screw size. Temporary joint-spanning external fixation before internal fixation of open intra-articular distal humeral fractures: A staged protocol. Predictors of postoperative complications of ilizarov external ring fixators in the foot and ankle. A research group at the University of Michigan found that internet use by orthopaedic patients had increased from 20% in 1998 to 46% in 2003. Expansion of internet access over the past decade is analogous to the recent proliferation of smartphones, extending online use to specific patient groups, affecting access to online health information, and potentially revolutionizing this divide. The 28-question survey, completed by 100 orthopaedic outpatients, evaluated associations between patient age, ethnicity, income, or education level, and their access to the internet, use to obtain information about their medical condition, privacy concerns during this online research, and patient use of mobile phones as a primary means of internet access. The internet was used by 57% of orthopaedic outpatients in our urban population, internet access decreased with age, and increased with income and education level, which were consistent findings from similar studies. Despite the inability to identify an association between ethnicity and internet access in this patient population, fewer Latinos sought information about a personal medical condition than did Caucasians or African Americans. Amongst patients who used their mobile phone as a primary method for online access, 74% were African American or Latino, significantly greater than 26% Caucasians. This deviation in online smartphone use in conjunction with the lack of disparities in internet use found between ethnic groups insinuates that mobile phones have provided ethnic minorities with greater internet access, and thus made a probable contribution to the narrowing of the "digital divide" amongst the races in our population of orthopaedic outpatients. Introduction the technological revolution triggered by the rapid growth of the internet has provided patients with unprecedented access to medical information. This study, therefore, aims to evaluate differencesinpatientdemographicsthatmayinfluenceinternet access in urban orthopaedic outpatients, determine if mobile access has narrowed the "digital divide" in our patients, and explore the variation in the patient use of the internet based on their ethnic background. The 103 patients who consented to participate were administered a survey in a private setting with a laptop and secure internet connection. In addition, two patients that completed the survey were under the age of 18 and one patient did not submit a finished survey. These three patients were also excluded and, consequently, the remaining 100 patients were included in our analysis. The remaining 20 questions were designed to ascertain information from the patients regarding their internet use in the following categories: 1. General internet access: use within the past year, modes of access, average use per day, main reasons for use, and primary search engines used. Five participants reported multiple education levels, and the highest level that they selected was exclusively used in our analysis. Annual household income levels that were originally ascertained in the survey based on levels of less than $10,000, $10,001 to $18,000, $18,001 to $35,000, $35,001 to $50,000, $50,001 to $100,000, and greater than $100,000, were then grouped into three categories of less than $18,000, $18,000 to $50,000, and 50,001 to greater than $100,000. This was done on the basis that results were similar amongst the groups that we combined, which was also noted and performed by Parekh in a study conducted at a hand surgery outpatient clinic. Differences in the categorical data was assessed using the chi squared test, and differences that were found to have a p < 0. Results Internet Access Of 100 patients attending the orthopaedic outpatient clinic in the urban setting of Philadelphia, 57% had used the internet within the past year. Younger patients less than 40 years of age were more likely than middle-aged patients of 40 to 50 years old to have used the internet (p <. Orthopaedic outpatients who had used the internet within the past year in different age groups of patients. Patients with an annual household income of less that $18,000 were less likely to have accessed the internet within the past year, as compared to those making between $18,000 and $50,000 (p <. An analogous finding was seen in patients that did not graduate high school, who were found to have accessed the internet within the last year significantly less than patients who graduated high school (p <. In contrast however, we were unable to demonstrate a statistically significant difference in access to the internet between Caucasian, African-American, and Hispanic patients in our study population. More explicitly, of these 57 patients, 19% reported that they had used the internet to find information regarding their health condition that was being addressed at the current orthopaedic visit, and in a similar question with 78 responses, 14% of patients stated that someone else had used the internet to obtain this information for the patient. Hispanic patients were found to have researched their medical condition on the internet less frequently than Caucasian or African American patients (Figure 2). The difference between Hispanics and Caucasians was nearly, but not statistically significant (p =. In contrast, patient internet use to find out about a personal health condition was not significantly different based on age, or annual household income in this urban orthopaedic outpatient population. The final aspect of this survey that pertained to access of the internet for medical information was used to assess the prevalence of privacy concerns when patients searched the internet for information on their medical condition. Of the 52 patients who responded, 62% expressed that they had concerns about privacy. Despite finding that African Americans (67%) and Hispanics (64%) more frequently expressed a concern for privacy on the internet than Caucasians (50%), this was not a statistically significant disparity between the ethnic groups. In the same way, we were also unable to demonstrate a significant association between annual household income and patient outlook on privacy while searching the internet for information about their medical condition. Patients who have used the internet to research a personal medical condition based on patient ethnicity amongst orthopaedic outpatients. Characteristics of Patient Internet Use Although part of this study relied on patient characteristics, which primarily included income, ethnicity, and smartphone use to assess disparities in internet access and use amongst orthopaedic outpatients, the survey also examined general elements of internet use in this population as a whole. Patients who attended orthopaedic clinics in this urban setting averaged three hours of internet use per day. Of these 56 responders that addressed their amount of internet use, the vast majority predominantly accessed the internet by Temple University Journal of Orthopaedic Surgery & Sports Medicine, Spring 2013 annual household income less than $10,000 and 21% with greater than $100,000. In doing this, the 57% of patients that we found to have access to the internet was identical to the percentage reported in a 2004 study of orthopaedic patients at the University of Pennsylvania, which Discussion consisted of a survey population that profoundly mirrored this study was designed to evaluate the level of internet ours in many of these aspects. Significant characteristics of access within a sample of patients attending orthopaedic internet access by these patients pertain to outpatient orthooutpatient clinics of an urban academic medical center and paedic care, including the use of the internet to obtain gento determine patient demographics that predict characteriseral health or medical information and to research a personal tics of patient internet use. The main reason patients used the internet was for e-mail or communication (85%), while only 33% of the 55 participants that responded to this question listed health or medical information as a main reason for use. In comparison, other main reasons these patients used the internet included 53% for entertainment, 49% for news, and 40% for shopping. Internet use and the process of obtaining information online is frequently initiated through search engines, and an additional evaluation of these 55 patients determined that Google was the most widely used search engine (80%), although the majority of patients used Google, Yahoo (56%), or both. Our study in the urban population of Philadelphia illustrated statistically significant greater use of the internet as the level of education achieved by the orthopaedic outpatient increased, which was determined by individually comparing patients with no high school diploma to high school graduates, patients who attended some college, and college graduates. An additional factor contributing to orthopaedic outpatient internet access had been previously discovered between age groups, with a range of 77% use in patients less than 30 years old to 16% use in those greater than 70 years old. In the setting of an orthopaedic outpatient population, research has not established patient race as a predictor of internet access. Despite the smaller percent of patients with internet access in our study, their disproportionately low household incomes was an improbable explanation for the inability of our study to identify a statistically significant variation in internet access contingent on patient race. Alternatively, race as predictor of internet use most plausibly proved unattainable because of the demographic underrepresentation of Caucasians and the extraordinary predominance 67 of African Americans in our survey populous at orthopaedic clinics in Philadelphia. Although this suggests some narrowing in the "digital divide" amongst African Americans, a more definite evaluation should be performed to better understand the extent to which increased use of mobile phones, as a primary source for internet access, has influenced this divide in orthopaedic patients of lower income. In a 2011 survey on health topics, Fox established that of participants who accessed the internet, 63% of Caucasians, 47% of African American, and 45% of Latinos used the internet to look for health information. Previously, it had been established that there were deficiencies in health topics on the internet that were important for patients, a finding that was particularly striking across Spanish-language sites, where more than half of the condition-related topics were not addressed. Although variation in linguistic characteristics did not contribute to a disparity in internet access in our population of orthopaedic outpatients as there was no significant variation between ethnic groups, the language barrier found to be unique to Latino patients in our study was the principle component underlying the propensity for Latinos to have used the internet less than other races to learn about a personal health condition. In medical patient populations, however, including in the orthopaedic outpatient setting,theinfluencethatethnicityhasoninternetuseforpersonal medical education remains undetermined. Despite providing useful insight into the internet access and characteristic of its use in the orthopaedic outpatient population, our study had a few shortcomings that may have hindered our ability to detect some statistically significant findings in this urban setting. Although the 100 patients who responded to the survey provided enough data to evaluate certain aspects of internet use in our study population, increasing the number of surveys administered, with the primary goals of increasing the size of the Caucasian and Latino groups while providing a greater subpopulation of patients who had access to the internet, would provide sufficient data to evaluate more of the subsequent questions that characterized use of the internet. In evaluating the design of the questionnaire, a shorter survey would have provided for a larger number of patients who chose to answer questions towards the end of the survey, which evaluated patient opinions and experiences based on a scale from strongly agree to strongly disagree. An additional oversight in the structure of the survey was the unexpected ability of patients to select multiple answers when describing their education level and 68 type of health insurance, as this prevented any statistically significant evaluation based on type of health insurance and forced us to analyze results based on education by the highest level of education reported. Finally, in our assessment of smartphone use as a primary source for patient internet access, asking patients about their ownership of a smartphone would have enabled us to determine if owning a phone withonlinecapacitieshadaninfluenceoninternetusebased on the race of the patient and on their annual household income. This was opposed to our study, which could only determine the percent of patients reporting their mobile phone as a primary way of obtaining internet access who were of a certain ethnic group or in the various categories of annual household income. Within the orthopaedics community, trends in outpatient access to the internet and in the characteristics of patient internet use had been shown to be predicted by age, income, education level, and furthermore, now additionally by ethnicity. Efficiently and effectively improving patient use of the internet to obtain medical information will benefit both the doctor and the patient by enhancing patient education, while also strengthening the doctor-patient relationship and ultimately enabling the doctor to provide a higher quality of patient care. Temple University Journal of Orthopaedic Surgery & Sports Medicine, Spring 2013 6. Readability of patient education materials from the American Academy of Orthopaedic Surgeons and Pediatric Orthopaedic Society of North America web sites. Prevalence of Internet use amongst an elective spinal surgery outpatient population. More online, doing more: 16 million newcomers gain Internet access in the last half of 2000 as women, minorities, and families with modest incomes continue to surge online 2001. Several subsequent studies identified turf characteristics and conditions as additional risk factors contributing to injuries. Since that time, many studies have looked at the shoe, the surface or both in regards to athletic injuries. While study designs have varied and findings have been inconsistent, the importance of this topic grows with the popularity of football from youth to professional levels. The incidence of ankle, foot, and knee injuries in high school players was recently reported to account for 37. The healthcare cost of treating these injuries has been estimated at many millions annually. Newer generations and engineering techniques have been applied to artificial turf. This has made an issue of interpreting seemingly outdated studies and their application for currentrecommendations. Arecentpublicationhasbriefly 70 highlighted a few historical points and findings and has called for more epidemiologic studies to investigate this area. After reviewing these articles, levels of evidence were assigned to each publication and included in Table 1. Articles were reviewed for historical contribution to the research subject and relevance to current shoe-surface interface technology. The pool of literature was analyzed for trends and errors that reoccurred throughout the last 40 years. Results the database search described above resulted in 32 publications covering the time period from 1969 to May 2012. As stated previously, in 1969 Hanely and Rowe identified that cleat fixation was a risk factor for injury. The following year, it was identified that surface characteristic were an additional potential risk factor and that increasingly popular artificial turf had an increased rate of injury compared to natural grass. Further Temple University Journal of Orthopaedic Surgery & Sports Medicine, Spring 2013 Table 1. From an injury standpoint, this was potentially a problem in that he proposed that "synthetic playing surfaces changed the complexion of the game by increasing player speed. It was shown that AstroTurf had a greater injury rate than grass, but a different artificial surface, Tartan Turf, actually had a lower injury rate in a high school football study. He defined the release coefficient (Force/Weight) and applied this value for guidelines of shoe and surface combinations and their safety factor. On the basis of study, it was concluded that the molded sole soccer type shoe with 15 cleats with a maximum cleat length of 1 /2 inch 1/2 length and a minimum cleat diameter of 1/2 inch as being safe on all playing surfaces, both grass and artificial. He further concluded that shoes with this sole configuration were safe on all surfaces, except those constructed with rubber soles, were not safe on all synthetic surfaces. A laboratory study concluded that lower torque was developed in polypropylenelike soles as compared to polyurethane and rubber soles.
This suggested some sort of historical continuity between them-descent with modification impotence smoking buy vardenafil 20mg otc, he called it intracavernosal injections erectile dysfunction buy 20mg vardenafil with mastercard. The problem was how to make sense historically chlamydia causes erectile dysfunction 20 mg vardenafil fast delivery, rather than miraculously impotence quotes vardenafil 20mg, of the particular adaptations that differentiate species erectile dysfunction books download free discount vardenafil 20mg online. This did not necessarily entail face-to-face competition but simply the fact that not all members of a species are equally likely to survive and breed erectile dysfunction kegel exercises discount vardenafil 10mg with amex. Those creatures will disproportionately thrive and breed erectile dysfunction biking 10 mg vardenafil with visa, and the next generation of the species will come to look just a bit more like them erectile dysfunction treatment without drugs buy vardenafil 20mg, on the average. The biology that Darwin learned in college had invoked a famous simile: a species is like a watch, meticulously crafted by a wise watchmaker, implying a heavenly species-maker. Darwin substituted a more powerful simile, arguing that a species is actually like a breed or strain of animals, rather than like a watch. But we know that a breed or strain of animals arises naturally, historically, by the actions of breeders who select certain features to characterize populations. Whether dogs, pigeons, or roses, the properties of living beings can change, and have changed, in quite dramatic ways by virtue of human activity in rather short periods of time. If people could make beagles and greyhounds and bulldogs by selecting the progenitors of particular stocks, then maybe nature could work to select progenitors as well, although more subtly and over vastly longer periods of time (see Figure 2. But in 1858 he received a manuscript from a fellow naturalist, Alfred Russel Wallace, who had come up Figure 2. The result was called On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, published on November 24, 1859. The origin of new species lay in the long-term biases of survival and reproduction in older species. Those nested patterns were the legacy of common ancestries; they were literally family resemblances. He wanted the discussion to be about the general process; consequently he wrote just a single line, near the end, about people: "Light will be thrown on the origin of man and his history" (Darwin 1859, 488). He was willing to acknowledge the possibility that life had "been originally breathed into a few forms or into one," but he was satisfied with having described the mechanism by which adaptive change has taken place in the organic world since then-in parallel with Isaac Newton, who famously refused to speculate on where gravity came from, focusing instead only on how it works (Darwin 1859, 490). A British scholar named Herbert Spencer had also come up with a similar idea, which he called "survival of the fittest" and he convinced Darwin that his phrase was synonymous with "natural selection. This confusion of human history (that is, the construction of social and political hierarchies) for evolutionary biology would prove to be a consistent irritation for students of human diversity and ancestry. This seeming paradox led Wallace into spiritualism and the possibility that all species of organisms had evolved. Darwin wrote him, "I hope you have not murdered too completely your own and my child" (Darwin, 1869). In 1871, the early British anthropologist Edward Tylor formally separated the evolution and study of "culture" from the biological properties of people. Furthermore, this cultural information was the product of historical process, not miracle. Within the academy, there was not too much reaction against the proposition that humans had descended with modification from an ape stock, and had then differentiated from that stock over the eons as a result of the differential preservation of favorable variations. The heart of Darwinism as applied to humans is simply ape ancestry and adaptive divergence. Evolution 33 But the early Darwinians were faced with a dilemma-in 1860, there was no fossil evidence linking humans to apes. He envisioned 12 different species of living peoples, each at different distances from the apes, thus sacrificing the full humanity of most people on the altar of Darwinism (see Figure 2. Scientists of the 1860s thought the full humanity of Africans was less important than evolution, Today that is morally repugnant. While Darwin and his English colleagues did not agree with these details, they nevertheless saw Haeckel as an ally in the broader struggle to get evolution accepted. The dominant theory of heredity at the time was known as blending inheritance, in which a child is a blend of the parents-like paint, if mom is red and dad is blue, then the child is purple (see Figure 2. The problem is that any descendants of purple child will never be as different as blue mom and red dad. Darwin fell back on a principle developed by Lamarck known as the "inheritance of acquired characteristics" or "use and disuse of organs. That way, variation can be reintroduced every generation, by virtue of this new pool of acquired characters. Unfortunately, an influential school of German biologists in the 1880s, led by August Weismann, had identified just two types of cells in bodies: reproductive or germ cells, and somatic or body cells. It was the germ cells that formed the next generation; the somatic cells, which form the body, comprise merely an evolutionary dead-end to aid in the transmission of the germline. Life could thus be seen as a continuous series of germ-cells, with adult bodies as transient receptacles grown up around them every generation. When you isolated particular traits, you saw that offspring were not midway between their parents; rather, they were like one or the other parent. The offspring of a plant with green peas and one with yellow peas was green, not chartreuse. The offspring of a plant with wrinkled peas and one with round peas was round, not wrinkly-round. This suggested, rather, that heredity worked like interacting particles that came into new combinations but fundamentally retained their structural integrity every generation. But the old Darwinian naturalists were working with quantitative variations in real populations-many of them intermediate, not extreme, in form. So, the Mendelians had a robust theory of heredity that had difficulty explaining natural patterns of variation, and the Darwinians had a robust theory of biological change that had difficulty accommodating discontinuous variation. One solution might be to reconceptualize all variation as fundamentally binary; the American geneticist Charles Davenport, for example, argued with considerable success that there were two kinds of people-smart and stupid-and that the stupid people simply had the allele for "feeblemindedness. A better solution came with the invention of population genetics, in works published around 1930 by the British geneticists Ronald Fisher and J. If we reduce a body to its genetic composition or genotype, and we reduce a species to its cumulative genetic composition, or gene pool, we can mathematically model the ways in which the gene pool can be transformed. There are rather few ways to accomplish it, and each has characteristic and predictable effects. This became the first part of the Synthetic Theory of Evolution, the extension of Mendelian genetics to population genetics and the formal mathematical study of how gene pools may be transformed through time. The second part involved the study of how species diversify in addition to simply changing, and it entailed integrating speciation and geography in the story of how animal species have come to be. The primary scholars involved were the RussianAmerican fruit fly geneticist Theodosius Dobzhansky, the German-American ornithologist Ernst Mayr, and the American paleontologist George Gaylord Simpson (see Figure 2. By the 1960s, then, biologists had a robust theory to explain the history of life. Selection could now be reduced to the favoring of certain genotypes over alternatives, which can make populations genetically adaptively different from one another. The genetic contact of populations, or gene flow, makes populations more similar to one another. Disrupting gene flow acts to divide gene pools, which is in turn stabilized by the development of reproductive barriers between the populations. These processes can be directly studied within living species and can be extrapolated and can adequately explain the differences we find among species. For example, not only is blood a powerful metaphor for heredity, but also it contains genetically controlled immunological properties that can be used to study evolution. It was known in this way by the 1920s that the blood of human and chimpanzee were more similar to one another than were the blood of horse and donkey (see Figure 2. By the mid-1960s, it was well established that the blood of human and chimpanzee were more similar to one another than either was to the blood of an orangutan. With greater precision, the actual amino acid sequences of some proteins could be established and compared across species. Thus, while humans are very easily distinguishable from gorillas physically Figure 2. With less than one percent difference in the structure of their hemoglobin, yet striking differences in anatomical form, communication, and behavior, there seems to be a paradox in their biochemical versus anatomical relationships. This led to some thoughtless early inferences from biochemists, such as suggesting that humans are merely variant gorillas, from the viewpoint of hemoglobin. But genetic variation more closely tracks the time since the species diverged from one another. By the late 1960s, molecular data were being used to test an important hypothesis about human evolution. Where physical anthropologist Sherwood Washburn thought that humans and African apes probably shared a common ancestor as recently as three to five million years ago, paleoanthropologist David Pilbeam felt that they had separated far earlier than that. Armed with the well-dated (but poorly reconstructed) dental remains of a 14-millionyear-old fossil called Ramapithecus, Pilbeam argued that Ramapithecus was a part of the human lineage, which in turn had to be at least that old (Figure 2. Thus, (3) Ramapithecus could not be on the human line 14 million years ago, because there was no separate human line 14 million years ago! We now see Ramapithecus differently, as part of the orangutan lineage, and we find that genetic or molecular evolution does indeed tend to track time, rather than adaptive divergence. Mutations are just as likely to arise within a gene as outside of a gene, yet when you compare species, you find more differences between genes. Because the genes do indeed function; consequently, random changes in a gene are far more likely to compromise that function than to improve it. There is a small probability that you might hit it in just the right way to improve its performance, but chances are good that you would make it worse. Similarly, a random change to an alreadyfunctioning molecule is far more likely to make it work worse than to make it work better. And by compromising the health of its bearer, such a mutation would be "weeded out" by natural selection (See the discussion in Chapters 3 and 4). We call these "synonymous mutations," and when we compare genes across species, we almost always find far more of them than we find of the mutations that do indeed change the structure of the gene product. So even though synonymous mutations are a small proportion of mutations, they predominate in cross-species comparisons of genes. This helps to explain why the genetics seems to track time while the anatomy seems to track adaptation. If most mutations are neutral, with no net effect on the fitness of the organisms that possess them, then (as statisticians calculated in the 1960s) they will spread through a population rarely and in proportion to the rate at which they arise. The mutation rate is a constant, so consequently, over time, neutral mutations will spread and come to differentiate populations in proportion to the time since those gene pools have been separated from one another. Bodily difference, Evolution 37 by contrast, interacts with the environment in important ways, and its evolution will track that interaction. Thus, biologists often envision evolution working on different hierarchical "levels": a genetic or molecular level and an anatomical level. Yet how do we simultaneously accommodate the knowledge that (1) genetics and anatomy are different levels, with one tracking time and the other adaptive divergence, and that (2) the genes somehow cause the anatomy? Animals are in fact reactive and adaptable beings, not passive and inert genotypes. Nor are species simply gene pools; rather, they are clusters of socially interacting and reproductively compatible organisms. So, accepting that evolutionary change is fundamentally genetic change, how do bodies nevertheless function and evolve? And accepting that speciation is ultimately a division of the gene pool, how do groups of animals nevertheless come to see one another as potential mates or competitors for mates, as opposed to just other creatures in the environment? These questions were raised in the 1980s by paleontologist Stephen Jay Gould, the leading evolutionary biologist of the late 20th century, to progress beyond the reductive assumptions that had guided the earlier generation. Gould spearheaded a movement to identify and examine higher-order processes and features of evolution that were not adequately explained by population genetics. For example, extinction, which was such a problem for biologists of the 1600s, could now be seen as playing a more complex role in the history of life than population genetics had been able to model. The crucial recognition was that there are two kinds of extinctions, each with different consequences: background extinctions and mass extinctions. Background extinctions are those that reflect the balance of nature, because in a competitive Darwinian world, some things go extinct and other things take their place. It sucks, but it is the way of all life: you come into existence, you endure, and you pass out of existence. They reflect not so much the balance of nature as the wholesale disruption of nature: many species from many different lineages dying off at roughly the same time-presumably as the result of some kind of rare ecological disaster. The situation may not be survival of the fittest as much as survival of the luckiest. Having made it through the worst, the survivors could now simply divide up the new ecosystem amongst themselves, since their competitors were gone. Something like this may well have happened about 65 million years ago, with mammals surviving and dinosaurs not. Something like this may be happening now, due to human expansion and environmental degradation. Note, though, that there is only a limited descriptive role here for population genetics: the phenomena we are describing are about organisms and species in ecosystems. For example, there are upwards of 15 species of gibbons but only two of chimpanzees. Gould suggested that species, as analytic units of nature, might have properties that are not reducible to the genes in their cells. For example, characteristic rates of speciation and extinction might be emergent properties of their ecologies and histories, and not properties of the genes. Consistent biases of speciation rates might well produce patterns of macroevolutionary diversity that are difficult to explain genetically and that need to be understood ecologically. Gould called such biases in speciation rates species selection-a higher-order process that invokes competition between species, in addition to the classic Darwinian competition between individuals. In the classical view, a species is continually adapting to its environment until it changes so much that it is a different species than it was at the beginning of this sentence (Eldredge and Gould 1972). That implies that the species is a fundamentally unstable entity through time, continuously changing to fit in. But suppose, argued Gould along with paleontologist Niles Eldredge, a species is more fundamentally stable through time and only really adapts as it is being founded? They called this idea punctuated equilibria, and it helps to explain certain features of the fossil record, notably the existence of small anatomical "gaps" between closely related fossil forms (see Figure 2. Its significance, once again, lies in the fact that although it incorporates genetics, it is not really a theory of genetics but a theory of groups of bodies in deep time. In response to the call for a theory of the evolution of form, the field of evo-devo-the intersection of evolutionary and developmental biology-arose. An embryo matures by the stimulation of certain cells to divide, forming growth fields. The interactions and relationships among these growth fields generate the structures of the body. Indeed, these genes were first identified by producing a bizarre mutant fruit fly that grew a pair of legs where its antennae were supposed to be. Certain genetic changes can alter the fates of cells and the body parts that they build; meanwhile, other genetic changes can simply affect the rates at which neighboring groups of cells grow and divide, thus producing physical bumps or dents in the developing body. The result of altering the relationships among these fields of cellular proliferation in the growing embryo is allometry, or the differential growth of body parts. As an animal gets larger-either over the course of its life or over the course of macroevolution-it often has to change shape in order to live at a different size. Many important physiological functions depend on properties of geometric area: the strength of a bone, for example, is proportional to its cross-sectional area. But area is a two-dimensional quality, while growing takes place in three dimensions-as an increase in mass or volume. As an animal expands, its bones necessarily weaken, because volume expands faster than area does. Consequently a bigger animal has more stress on its bones than a smaller animal does and must evolve bones even thicker than they would be by simply scaling the animal up proportionally. In other words, if you expand a mouse to the size of an elephant, it will nevertheless still have much thinner bones than the elephant does. Thus, a giant mouse would have to change aspects of its form to maintain function at a larger size (see Figure 2. Physiologically, we would like to know how the body "knows" when to turn on and off the genes that regulate growth to produce a normal animal. Evolutionarily, we would like to know how the body "learns" to alter the genetic on/off switch (or the genetic "slow down/speed up" switch) to produce an animal that looks different. Moreover, since organisms differ from one another, we would like to know how the developing body distinguishes a range of normal variation from abnormal, pathological variation. And finally, how does abnormal variation eventually become normal in a descendant species? Most died, but a few survived somehow by developing a weird physical feature: a second thorax, with a second pair of wings. Waddington bred these flies and soon developed a stable line of flies who would reliably develop a second thorax when grown in ether. Then he began to lower the concentration of ether, while continuing to selectively breed the flies that developed the strange appearance. Eventually he had a line of flies that would stably develop the "bithorax" phenotype even when there was no ether; it had become the "new normal. Waddington was thus able to mimic the inheritance of acquired characteristics: what had been a trait stimulated by ether a few generations ago was now a normal part of the development of the descendants. Waddington recognized that he had performed a selection experiment on genetic variants, yet he had not selected for particular traits but, rather, for the physiological tendency to develop particular traits when appropriately stimulated. He called that tendency plasticity and its converse, the tendency to stay the same even under weird environmental circumstances, canalization.
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