Interacting Gears Synchronize Propulsive Leg Movements in a Jumping Insect

Joint Action Many small insects are impressive jumpers, but large leaps and small bodies pose biomechanical challenges. Burrows and Sutton (p. 1254 ) show that the nymphal planthopper Issus has interlocking gears on their hindleg trochanters that act together to cock the legs synchronously before triggering forward jumps. At the final molt, the gears are swapped for a high-performance friction-based mechanism because the risk of breaking a gear is high, the options for repair during molting are gone, and, moreover, the animal is bigger and stronger. </jats:p

Biomechanics: Passive forces set the stage for stick insects

Short dispatch, no abstrac

Why do Large Animals Never Actuate Their Jumps with Latch-Mediated Springs? Because They can Jump Higher Without Them.

As animals get smaller, their ability to generate usable work from muscle contraction is decreased by the muscle's force-velocity properties, thereby reducing their effective jump height. Very small animals use a spring-actuated system, which prevents velocity effects from reducing available energy. Since force-velocity properties reduce the usable work in even larger animals, why don't larger animals use spring-actuated jumping systems as well? We will show that muscle length-tension properties limit spring-actuated systems to generating a maximum one-third of the possible work that a muscle could produce-greatly restricting the jumping height of spring-actuated jumpers. Thus a spring-actuated jumping animal has a jumping height that is one-third of the maximum possible jump height achievable were 100% of the possible muscle work available. Larger animals, which could theoretically use all of the available muscle energy, have a maximum jumping height that asymptotically approaches a value that is about three times higher than that of spring-actuated jumpers. Furthermore, a size related "crossover point" is evident for these two jumping mechanisms: animals smaller than this point can jump higher with a spring-actuated mechanism, while animals larger than this point can jump higher with a muscle-actuated mechanism. We demonstrate how this limit on energy storage is a consequence of the interaction between length-tension properties of muscles and spring stiffness. We indicate where this crossover point occurs based on modeling and then use jumping data from the literature to validate that larger jumping animals generate greater jump heights with muscle-actuated systems than spring-actuated systems

Three Studies on Climate and Human Variety in France

This study explores three variants of climate theory in France by Jean Bodin, Montesquieu, and Buffon, the origins of which are traceable back to Ancient Greece. It shows that arguments about the primacy of climatic influence in human affairs were of central importance to each of these theorists despite differences in the historical setting within which their views were set forth and their overriding scholarly and theoretical interests. As we will see, in each case the problems these theorists wanted to solve was that of human diversity. Climate theory was crucial in their attempts to understand both why there were so many manifestly different kinds of people and with them, differing laws, customs, institutions, physical shapes, colors, and size. In addition, climate theory served for Bodin to explain the changes that had befallen humans since the Fall, for Montesquieu to repudiate Catholic dogma, and for Buffon to document the unity of the human species. In brief, climate theory means the combination of physical factors -- air temperature, winds, geography, exposure to the sun, proximity to water, exact location to which people are exposed. By an examination of these elements these theorists believed that they could account for the distinguishing characteristics that differentiated whole groups. It was believed that a careful documentation of climate would explain why difference itself existed. The tenacity with which theories of climate have perpetuated themselves over two millennia of Western civilization attests to the powerful appeal such notions had for those seeking to explain phenomena that at first were startling and perplexing. From the first efforts to understand localized disease and explain human variation in Greek medicine to contemporary examinations of weather patterns and their effects on human development, the idea that climate profoundly influenced not just the physical circumstances but also the social, psychological, and biological makeup of diverse peoples has attracted numerous adherents. By examining the work of Bodin, Montesquieu, and Buffon this study seeks to explain the attraction, inner workings, and multiple applications of climate theory in France. Jean Bodin -- jurist, historian, and political theorist lived in the era of the French Wars of Religion, an epoch of profound social, political, and religious upheaval. Bodin focused on "universal history" in an effort to throw light on the events of his time. Deeply troubled by the conflict between Catholic and Protestant he sought to explain why diverse laws, customs, and institutions -especially religious institutions -- had come to exist. He pondered why so many different kinds of people existed when all existence owed its origin to God the creator, whose powers had first breathed life in human beings in the Garden. Since the time of that distant paradise much had changed. The Fall inaugurated a ceaseless chain of permutations and alterations in human history so that by his time the numerous peoples known, and their concomitant varieties of laws, customs, and institutions, appeared to contradict the Bible's central tenet of common human descent. Bodin used his concept of "universal history" -- within which his climate theory was embedded to explain what had initiated these events and to reconcile them with the Biblical account of Genesis. It was within this framework of dual necessity -- explaining the peculiarities of historical development and the deviations that had occurred since the Creation, that Bodin gathered and used ideas about climatic influences. Despite the essential sameness of all human beings as created by God, diversity in both physical form and social life had appeared, thanks to the formative role of climate. Bodin's ultimate argument was that because climatic influence could be only partially mitigated by human efforts, diversity had to be recognized and tolerated. This overall historical interpretation buttressed the political and social cause most important to him -- encouraging tolerance among the warring religious factions of sixteenth-century France. Montesquieu lived in an age substantially different from that of Bodin. On the surface it appeared that the burning issues of Bodin's time had been resolved in favor of the French crown and Catholicism. The appearance of calm was misleading, however, for forces -- economic, social, and political were slowly gathering that would cause deep conflicts in the second half of the eighteenth century and ultimately help bring revolution to France. Traditional precepts of a divinely-inspired social order created and perpetuated by the laws of God were submitted to the calculating stare of Reason and found wanting. New explanations appeared that challenged old canons of thought and ushered in an era of intellectual fermentation. "Natural Law" gradually supplanted the laws of the exclusive Christian God, but it in turn seemed -- as recognition of human diversity intensified -- increasingly inadequate to explain the maintenance of order in the world of human affairs. Diversity was a vexed problem to Montesquieu because it seemed to contradict the universal application of Natural Law. Thus when attempting to explain the laws of nature and those of human societies, Montesquieu appealed to climate as one way of making comprehensible the differences that existed between humans -- and their various "positive laws" -- and still remain faithful to universal Natural Law. By turning to climate Montesquieu was able to retain Natural Law, explain the diversity immanent in human societies, and never waver from the belief that Natural Law was best exemplified in Europe, where political rule, morality, and social development best conformed to Natural Law. Thus climate theory allowed Montesquieu at one and the same time to relative cultural values and norms (for which he has been applauded as "the founder of sociology") and to reassert over and beyond diversity the superiority of the European way of doing things. Although Buffon's subject matter -- natural history -differed from Montesquieu's, he nonetheless shared many of Montesquieu's characteristic concerns: the laws of development governing societies; the variety of human beings throughout the world; and in addition an interest in reconciling human diversity with the belief that all humans emanated from one source, the white European. Working within his system of natural history, Buffon was able to create a vast yet deceptively simple explanation that resolved the tension that existed between the variety of humans and his conviction that Europe epitomized the high point of development. His theory of climate fulfilled this need by preserving all of these tenets -- unity, variety, levels of development -- by postulating that all human beings had deviated from the European model because of migration, climatic exposure, and the consumption of poor foodstuffs. The theme which united all three theorists was the need to decipher why different kinds of human beings inhabited the earth; why they had developed peculiar social practices and customs; and why their institutions differed from those most familiar to them. The long tradition of ascribing such differences to climate admirably fulfilled their requirements.Histor

Successful Desensitization to Docetaxel after Severe Hypersensitivity Reactions in Two Patients

Purpose Two cases of successful desensitization to docetaxel after severe hypersensitivity reactions are reported. Summary Two patients with gynecological malignancies (uterine leiomyosarcoma and ovarian adenocarcinoma) experienced severe hypersensitivity reactions with docetaxel, including flushing, numbness, sharp radiating pain, severe nausea and vomiting, apnea, and unresponsiveness. Both patients received ondansetron before docetaxel. One patient received dexamethasone, diphenhydramine, and famotidine premedication before docetaxel, as she had previously reacted to paclitaxel. Docetaxel infusions were stopped, and the reactions were treated with diphenhydramine and dexamethasone (one patient also received famotidine). After resolution of symptoms, the docetaxel was not reinitiated due to the nature of the reactions. For the next cycle, both patients received a graded drug challenge or desensitization. Both were pre-medicated with dexamethasone, diphenhydramine, and famotidine. The docetaxel was given as infusions of 0.1%, 1%, and 10% of the dose, with each infusion given over one hour. After this, the remainder of the dose was infused over one hour. Both patients tolerated this desensitization well and completed a total of three and four cycles each. The first patient to receive the desensitization did complain of chest pain during the first desensitization, and the infusion rate was decreased to administer the drug over two hours. After she tolerated two cycles of two-hour infusions, the infusion rate was increased to administer each docetaxel infusion over one hour. Conclusion Two patients who had severe hypersensitivity reactions to docetaxel successfully received further docetaxel doses via a desensitization procedure that involved the sequential administration of solutions containing increasing concentrations of the drug

Mantises exchange angular momentum between three rotating body parts to jump precisely to targets.

Flightless animals have evolved diverse mechanisms to control their movements in air, whether falling with gravity or propelling against it. Many insects jump as a primary mode of locomotion and must therefore precisely control the large torques generated during takeoff. For example, to minimize spin (angular momentum of the body) at takeoff, plant-sucking bugs apply large equal and opposite torques from two propulsive legs [1]. Interacting gear wheels have evolved in some to give precise synchronization of these legs [2, 3]. Once airborne, as a result of either jumping or falling, further adjustments may be needed to control trajectory and orient the body for landing. Tails are used by geckos to control pitch [4, 5] and by Anolis lizards to alter direction [6, 7]. When falling, cats rotate their body [8], while aphids [9] and ants [10, 11] manipulate wind resistance against their legs and thorax. Falling is always downward, but targeted jumping must achieve many possible desired trajectories. We show that when making targeted jumps, juvenile wingless mantises first rotated their abdomen about the thorax to adjust the center of mass and thus regulate spin at takeoff. Once airborne, they then smoothly and sequentially transferred angular momentum in four stages between the jointed abdomen, the two raptorial front legs, and the two propulsive hind legs to produce a controlled jump with a precise landing. Experimentally impairing abdominal movements reduced the overall rotation so that the mantis either failed to grasp the target or crashed into it head first.GPS was supported by HFSP grant LT00422/2006-C. DAC was funded by a Leverhulme Trust grant F/09 364/K to S.R. Ott, University of Leicester, whom we thank for his support.This is the accepted manuscript. The final version is available at http://www.cell.com/current-biology/abstract/S0960-9822%2815%2900086-X

Graphical augmentations to the funnel plot assess the impact of additional evidence on a meta-analysis

AbstractObjectiveWe aim to illustrate the potential impact of a new study on a meta-analysis, which gives an indication of the robustness of the meta-analysis.Study Design and SettingA number of augmentations are proposed to one of the most widely used of graphical displays, the funnel plot. Namely, 1) statistical significance contours, which define regions of the funnel plot in which a new study would have to be located to change the statistical significance of the meta-analysis; and 2) heterogeneity contours, which show how a new study would affect the extent of heterogeneity in a given meta-analysis. Several other features are also described, and the use of multiple features simultaneously is considered.ResultsThe statistical significance contours suggest that one additional study, no matter how large, may have a very limited impact on the statistical significance of a meta-analysis. The heterogeneity contours illustrate that one outlying study can increase the level of heterogeneity dramatically.ConclusionThe additional features of the funnel plot have applications including 1) informing sample size calculations for the design of future studies eligible for inclusion in the meta-analysis; and 2) informing the updating prioritization of a portfolio of meta-analyses such as those prepared by the Cochrane Collaboration

Control of high‑speed jumps: the rotation and energetics of the locust (Schistocerca gregaria)

Locusts (Schistocerca gregaria) jump using a latch mediated spring actuated system in the femur-tibia joint of their metathoracic legs. These jumps are exceptionally fast and display angular rotation immediately after take-off. In this study, we focus on the angular velocity, at take-off, of locusts ranging between 0.049 and 1.50 g to determine if and how rotation-rate scales with size. From 263 jumps recorded from 44 individuals, we found that angular velocity scales with mass−0.33, consistent with a hypothesis of locusts having a constant rotational kinetic energy density. Within the data from each locust, angular velocity increased proportionally with linear velocity, suggesting the two cannot be independently controlled and thus a fixed energy budget is formed at take-off. On average, the energy budget of a jump is distributed 98.7% to translational kinetic energy and gravitational potential energy, and 1.3% to rotational kinetic energy. The percentage of energy devoted to rotation was constant across all sizes of locusts and represents a very small proportion of the energy budget. This analysis suggests that smaller locusts find it harder to jump without body rotation