Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico

Virginia striatula is a viviparous snake with a complex pattern of embryonic nutrition. Nutrients for embryonic development are provided by large, yolked eggs, supplemented by placental transfer. Placentation in this species is surprisingly elaborate for a predominantly lecithotrophic squamate reptile. The embryonic-maternal interface consists of three structurally distinct areas, an omphalallantoic placenta and a regionally diversified chorioallantoic placenta. The chorioallantoic placenta over the embryonic hemisphere (paramesometrial region) of the egg, features close apposition of embryonic and uterine blood vessels because of the attenuate form of the interceding epithelial cells. The periphery of the chorioallantoic placenta, which is adjacent to the omphalallantoic placenta, is characterized by a simple cuboidal uterine epithelium apposed to a stratified cuboidal chorionic epithelium. There are no sites with attenuate epithelial cells and close vascular apposition. The morphology of the omphalallantoic placenta is similar to that of the peripheral chorioallantoic placenta, except that the height of uterine epithelial cells is greater and allantoic blood vessels are not associated with the embryonic epithelium. The functional capabilities of the three placental regions are not known, but structural characteristics suggest that the omphalallantoic placenta and peripheral zone of the chorioallantoic placenta are sites of nutritional provision via histotrophy. The paramesometrial region of the chorioallantoic placenta is also nutritive, in addition to functioning as the primary embryonic respiratory system. The structure of the chorioallantoic placenta of V. striatula is a new placental morphotype for squamate reptiles that is not represented by a classic model for the evolution of reptilian placentation.

Background: Venomous snakebite and its effects are a source of fear for people living in southern Nepal. As a result, people have developed a negative attitude towards snakes, which can lead to human-snake conflicts that result in killing of snakes. Attempting to kill snakes increases the risk of snakebite, and actual killing of snakes contributes to loss of biodiversity. Currently, snake populations in southern Nepal are thought to be declining, but more research is needed to evaluate the conservation status of snakes. Therefore, we assessed attitudes, knowledge, and awareness of snakes and snakebite by Chitwan National Park's (CNP) buffer zone (BZ) inhabitants in an effort to better understand challenges to snake conservation and snakebite management. The results of this study have the potential to promote biodiversity conservation and increase human health in southern Nepal and beyond. Methods: We carried out face-to-face interviews of 150 randomly selected CNP BZ inhabitants, adopting a cross-sectional mixed research design and structured and semi-structured questionnaires from January-February 2013. Results: Results indicated that 43 % of respondents disliked snakes, 49 % would exterminate all venomous snakes, and 86 % feared snakes. Farmers were the most negative and teachers were the most ambivalent towards snakes. Respondents were generally unable to identify different snake species, and were almost completely unaware of the need of conserve snakes and how to prevent snakebites. Belief in a snake god, and the ability of snakes to absorb poisonous gases from the atmosphere were among many superstitions that appeared to predispose negativity towards snakes of BZ residents. Conclusion: People with predisposed negativity towards snakes were not proponents of snake conservation. Fear, negativity, ambivalence towards, and ignorance about, snakes and the need for snake conservation were strong indicators of the propensity to harm or kill snakes. It seems that if wanton killing of snakes continues, local snake populations will decline, and rare and endangered snake species may even become locally extirpated. Moreover, inappropriate perception and knowledge about snakes and snakebites may put BZ people at increased risk of venomous snakebite. Therefore, intensive, pragmatic educational efforts focused on natural history and ecology of snakes and prevention of snakebite should be undertaken in communities and at schools and universities.

No description available.

Snakes are probably the best example of evolutionarily life-threatening stimulus as they have been one of the first predators of primates and mammals in general. In recent years, it has been shown that snake images produce specific behavioral and electrophysiological reactions in humans, provoking enhanced brain activity over the occipital cortex compared with pictures of other animals. The present study investigated the hypothesis that the response to snake images is independent from awareness. Subjects (n=27) were asked to observe pictures of threatening and non-threatening animal stimuli, presented rapidly and in random order on a screen. Awareness level was manipulated using 4 different conditions of backward masks. Event Related Potentials (ERPs) showed that activity over the occipital cortex was clearly more pronounced for snake images than for the other images, but only in unmasked condition. / Ormar är sannolikt ett av de bästa exemplen på ett evolutionärt livshotande stimuli då de utgjort ett av de första rovdjuren för primater och däggdjur i allmänhet. På senare år har man visat att bilder på ormar producerar specifika beteenden och elektrofysiologiska reaktioner hos människan, och ökad hjärnaktivitet i occipitalkortex jämfört med bilder på andra djur. Föreliggande studie undersökte hypotesen att responsen till ormbilder är oberoende från medvetandet. Deltagarna (n=27) ombads observera bilder på hotfulla respektive icke-hotfulla djurstimuli som presenterades snabbt och i slumpvis ordning på skärmen. Nivå av medvetande manipulerades genom att använda fyra olika betingelser av bakåt maskering. Event-relaterade potentialer (ERPs) visade att aktiviteten över occipitalkortex var betydligt mer uttalad för ormbilder jämfört med andra bilder, men bara i den icke-maskerade betingelsen.

No description available.

The epidemiology of snakebite injury in the Amazonian regions of Ecuador Introduction: Morbidity and mortality from snakebite envenomations is a major public health issue in remote areas of under-developed countries. Several attempts have been made to approximate the impact of snakebites worldwide, however these are assumed to be underestimations due to the lack of documentation on the local level. Ecuador's Amazonian region lacks a comprehensive community-based surveillance system, however it is unique in that an aero-medical transport system is in place to transfer the patients requiring hospitalization to one of the five urban medical centers. Beginning in 1998, Servicio Aéreo Misional (SAM), one of the two transport companies serving three of the rural provinces, began documenting flight data including the demographics of patients and their diagnoses. Methods: The SAM database was used to conduct a retrospective study to describe the incidence, patient demographics and geographic location of snakebite injuries in three rural provinces of Ecuador. SPSS was used for frequencies and Chi squares analyses. Results: In the years 2003 to 2005 there were a total of 1,340 aero-medical transports in this region. Of those, snakebite injuries constituted 4.2% of all medical diagnoses. The majority of snakebites occurred in males (p=0.027) aged 10-29 (p<0.001) and were concentrated in the low-lying areas of the province of Morona-Santiago. Discussion: These results describe the distribution of snakebites; efforts are now underway to identify the risk factors involved in this patient population. This information would then be used to optimize prevention and treatment.

Search and rescue mobile robots have shown great promise and have been under development by the robotics researchers for many years. They are many locomotion methods for different robotic platforms, including legged, wheeled, flying and hybrid. In general, the environment that these robots would operate in is very hazardous and complicated, where wheeled robots will have difficulty physically traversing and where legged robots would need to spend too much time planning their foot placement. Drawing inspiration from biology, we have noticed that the snake is an animal well-suited to complicated, rubble filled environments. A snake’s body has a very simple structure that nevertheless allows the snake to traverse very complex environments smoothly and flexibly using different locomotion modes. Many researchers have developed different kinds of snake robots, but there is still a big discrepancy between the capabilities of current snake robots and natural snakes. Two aspects of this discrepancy are the rigidity of current snake robots, which limit their physical flexibility, and the current techniques for control and motion planning, which are too complicated to apply to these snake robots without a tremendous amount of computation time and expensive hardware. In order to bridge the gap in flexibility, pneumatic soft robotics is a potential good solution. A soft body can absorb the impact forces during the collisions with obstacles, making soft snake robots suitable for unpredictable environments. However, the incorporation of autonomous control in soft mobile robotics has not been achieved yet. One reason for this is the lack of the embeddable flexible soft body sensor technology and portable power sources that would allow soft robotic systems to meet the essential hardware prerequisites of autonomous systems. The infinite degree of freedom and fluid-dynamic effects inherent of soft pneumatics make these systems difficult in terms of modeling, control, and motion planning: techniques generally required for autonomous systems. This dissertation addresses fundamental challenges of soft robotics modeling, control, and motion planning, as well as the challenge of making an effective soft pneumatic snake platform. In my 5 years of PhD work, I have developed four generations of pressure operated WPI soft robotics snakes (SRS), the fastest of which can travel about 220 mm/s, which is around one body per second. In order to make these soft robots autonomous, I first proposed a mathematical dynamical model for the WPI SRS and verified its accuracy through experimentation. Then I designed and fabricated a curvature sensor to be embedded inside each soft actuator to measure their bending angles. The latest WPI SRS is a modularized system which can be scaled up or down depending on the requirements of the task. I also developed and implemented an algorithm which allows this version of the WPI SRS to correct its own locomotion using iterative learning control. Finally, I developed and tested a motion planning and trajectory following algorithm, which allowed the latest WPI SRS to traverse an obstacle filled environment. Future research will focus on motion planning and control of the WPI SRS in outdoor environments utilizing the camera instead of the tracking system. In addition, it is important to investigate optimal control and motion planning strategies for mobile manipulation tasks where the SRS needs to move and manipulate its environment.. Finally, the future work will include the design, control, and motion planning for a soft snake robot where each segment has two degrees-of-freedom, allowing it to lift itself off the ground and traverse complex-real-world environments.

Venoms from the most poisonous snakes found in Saudi Arabia were assessed for their physical and chemical characteristics and for their enzymatic and biological activities. Venom from Atractaspis microlepidota was the most lethal in mice followed by the elapids Naja haje arabica and Walterinnesia aegyptia. Among the vipers, Cerastes cerastes venom was the most lethal whereas the remainder (Echis pyramidum, Echis coloratus and Bitfis arietans) showed similar but lower lethality. Antivenoms were raised in sheep by immunising with a low dose of venom (0.5mg) which was then doubled every four weeks. To optimise the antibody response, groups of sheep were immunised with a low, medium and high dose and the monthly bleeds were assessed by ELISA and small-scale affinity chromatography. The immunoglobulin fraction was partially purified by sodium sulphate precipitation and digested with either papain, to form Fab fragments, or with pepsin to produce F(ab)2. The different antivenom fractions produced were characterised and assessed for their ability to neutralise the enzymatic and biological activities of the corresponding venoms. Fab was equally effective as F(ab)2 in most enzymatic and biological assays but the two fractions were less efficient than IgG. The ovine Fab provided good protection in mice against the lethality of these venoms and effectively neutralised their biological and enzymatic activities. The commercial antivenoms currently available in Saudi Arabia showed only partial neutralisation of the enzymatic and biological activities of these venoms and showed in vivo protection only when using large amounts. They offered no protection against W. aegyptia venom. The monospecific ovine Fab raised against E. pyramidum and E. coloratus venoms were more efficient than the polyspecific Fab raised against a mixture of the two venoms.

Orientador: Hussam el Dine Zaher / Banca: Denis Otavio Vieira de Andrade / Banca: Giovanna Gondim Montingelli / Resumo: Oxyrhopus clathratus é uma serpente com distribuição restrita à Mata Atlântica que apresenta grande variação de coloração, de forma do hemipênis e folidose. Estas variações foram por muito tempo mal compreendidas, causando problemas na identificação, reconhecimento e sinonímia de diferentes espécies. Este estudo analisou material de toda a distribuição geográfica da espécie e a série tipo, buscando avaliar pela primeira vez como estas e outras variações intraespecíficas ocorrem em O. clathratus analisando separadamente cada variável em relação à geografia e à altitude, explicando como estas diferenças se comportam dentro da espécie e se justificam a separação em mais de uma espécie. O resultado destas análises revelou que O. clathratus é uma única espécie com diversas variações intraespecíficas como a presença de três distintos padrões de coloração (Melânico, Melânico com bandas e Bandado) que se sobrepõe geograficamente, com indivíduos melânicos e com menos bandas tendendo a se concentrar ao sul do transecto; o hemipênis com ornamentação padrão, porém com freqüente variação entre as formas "T" e "Y", que ocorrem sem estruturação geográfica ou altitudinal; escama loreal geralmente ausente sendo esta uma característica única de O. clathratus em relação às demais espécies do gênero. A comparação destas variações com a série tipo da espécie, e a comparação entre os dois sintipos, levou à determinação do lectótipo e paralectótipo da espécie / Abstract: Oxyrhopus clathratus is a snake which presents restrict distribution on the South America Atlantic Forest and presents a great variable pattern of body color, shape of the hemipenis and pholidosis. These variations have long been misunderstood, causing problems in identification, recognition and synonymy of different species. This study examined material from all the geographical distribution of the species and the type series, seeking for the first time how these and other intraspecific variation occurs in O. clathratus analyzing each variable separately in relation to geography and altitude, explaining how these differences behave within the species and if they justify the separation in more than one species. The result of the analysis showed that O. clathratus is a single species with several intraspecific variations shuch as the presence of three distinct body color patterns (body melanic, body melanic with bands and body with bands) that overlap themselves geographically, with melanic individuals and individuals with less number of bands tending to concentrate on the south of the transect; the hemipenis presents a general patter of ornamentation, but with frequent variation between the "T-shape" and "Y-shape" forms, which occur without geographical or altitudinal structuring; loreal scales usually absent being this an O. clathratus's unique feature in relation to all other species of the genus. The comparison of these variations with the type series of species, and a comparison between the two syntypes, led to the determination of the lectotype and paralectotype of the species / Mestre