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1
Ge, Liehui. "Synthetic Gecko Adhesives and Adhesion in Geckos." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1294161826.
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Lopez, Stephanie M. "Effects of Digital Hyperextension on Self-Cleaning in the Tokay Gecko (Gekko gecko)." Akron, OH : University of Akron, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1248642491.
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Thesis (M.S.)--University of Akron, Dept. of Biology, 2009."August, 2009." Title from electronic thesis title page (viewed 10/14/2009) Advisor, Peter Niewiarowski; Co-Advisors, Todd Blackledge, Ali Dhinojwala; Department Chair, Monte Turner; Dean of the College, Chand Midha; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
3
Yan, Kai. "Calcium binding proteins and GAD immunoreactivity in the auditory system of Gekko Gecko." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8193.
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Thesis (M.S.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Biology. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Cole, Nicholas Carl. "The ecological impact of the invasive house gecko Hemidactylus frenatus upon endemic Mauritian geckos." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419134.
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Kabiri, Farnaz Kabiri. "Gecko Adhesion on Soft Surfaces." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1516061596336554.
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Menguc, Yigit. "Gecko-Inspired, Controlled Adhesion and Its Applications." Research Showcase @ CMU, 2012. http://repository.cmu.edu/dissertations/188.
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Gecko feet stick to almost anything, in almost any condition (including underwater and in space), but do not stick unintentionally, do not stick to dirt, and enable the gecko to literally run up the walls. When climbing a smooth surface, geckos can attach and detach each foot very quickly (detaching a foot takes 15 milliseconds) and with almost no noticeable force, but if attached perfectly they could theoretically hold tens of times their body weight. In contrast to gecko adhesion, conventional adhesives, made of soft tacky materials, tend to leave residues, pick up dirt easily, stick to themselves strongly and are useless underwater. Gecko feet rely on completely different principles, utilizing arrays of tiny mechanical structures made of very stiff protein which react to pressing and dragging with some very smart behavior. This thesis work is primarily concerned with taking inspiration from the principles of gecko-adhesion in order to control the attachment of synthetic structured adhesives.
We present gecko-inspired angled elastomer micropillars with flat or round tip endings as compliant pick-and-place micromanipulators. The pillars are 35 μm in diameter, 90 μm tall, and angled at an inclination of 20°. By gently pressing the tip of a pillar to a part, the pillar adheres to it through intermolecular forces. Next, by retracting quickly, the part is picked from a given donor substrate. During transferring, the adhesion between the pillar and the part is high enough to withstand disturbances due to external forces or the weight of the part. During release of the part onto a receiver substrate, the contact area of the pillar to the part is drastically reduced by controlled vertical or shear displacement, which results in reduced adhesive forces. The maximum repeatable ratio of pick-to-release adhesive forces was measured as 39 to 1. We find that a flat tip shape and shear displacement control provide a higher pick-to-release adhesion ratio than a round tip and vertical displacement control, respectively. We present a model of forces to serve as a framework for the operation of this micromanipulator. Finally, demonstrations of pick-and-place manipulation of μm-scale silicon microplatelets and a cm-scale glass cover slip serve as proofs of concept. The compliant polymer micropillars are safe for use with fragile parts, and, due to exploiting intermolecular forces, could be effective on most materials and in air, vacuum, and liquid environments.
We present a study of the self-cleaning and contamination resistance phenomena of synthetic gecko-inspired adhesives made from elastomeric polyurethane. The phenomenon of self-cleaning makes the adhesive foot of the gecko robust against dirt, and makes it effectively sticky throughout the lifetime of the material (within the molting cycles). So far synthetic gecko adhesives fail to capture this behavior and self-cleaning remains the least studied characteristic in the field geckoinspired adhesives. In this work we use two distinct arrays of micropillars with mushroom-shaped tips made from polyurethane. The two geometries we use all have the same aspect ratios of pillar height to base diameter of about 2 to 1, and all have mushroom tips that are twice the diameter of base. The pillar tip diameters are 20 μm and 95 μm, and we will refer to them as the small and large pillars, respectively. We contaminate the adhesives with simulated dirt particles in the form of well-characterized soda lime glass spheres ranging in diameter from 1 to 250 μm. Both micropillar arrays recovered adhesive strength after contamination and cleaning through dry, shearing contact with glass. In a best case scenario, we found that large pillars contaminated with 150-250 μm diameter particles can rid the tips of contaminating particles completely and recover 90% of the initial adhesive strength. This finding is significant because it is the first demonstration of adhesion recovery through dry self-cleaning by contact to a non-sticky cleaning substrate. The degree to which adhesion is recovered is superior to any conventional adhesive and is nearly identical to the gecko itself.
This thesis presents a study of controlling adhesion in gecko-inspired adhesives. This control is achieved by maximizing or minimizing attachment strength on demand by simple mechanical loading, and enables robotic manipulation tasks and the recovery of adhesion after contamination. Looking forward, we can predict what is possible for gecko-inspired adhesives if the discoveries in this thesis are implemented, and if other shortcomings in the field are resolved. Looking at the applications already under development, it seems clear that medical adhesives have great potential, and climbing robots might achieve significant utility. In consumer products, gecko-adhesives might replace Velcro®and zippers in clothing, and might become a critical component in sports gear, e.g. soccer goal keeper and rock climber gloves. The reversible, controllable nature of the adhesion, as well as its incredible bonding strength, suggests more impressive possibilities for gecko-inspired adhesives: perhaps it might act as a fastener for temporary or emergency construction. We might yet see rolls of single-sided and double-sided gecko-tape sold in hardware stores, not as a replacement for duct tape, but as a replacement for nails, staples and screws.
7
Yu, Lan. "Adhesive Force of a Single Gecko Seta." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1523202746417773.
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Najem, Johnny F. "Gecko-Inspired Electrospun Flexible Fiber Arrays for Adhesion." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1340465711.
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Wong, Andrew Carlton Edward. "Longitudinal studies on tooth replacement in the leopard gecko." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54273.
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The leopard gecko is an emerging reptilian model for the molecular basis of indefinite tooth replacement. Here we characterize the tooth replacement frequency and pattern of tooth loss in the normal adult gecko. We chose to perturb the system of tooth replacement by activating the Wingless signaling pathway (Wnt). Misregulation of Wnt leads to supernumerary teeth in mice and humans. We hypothesized by activating Wnt signaling with LiCl, tooth replacement frequency would increase. To measure the rate of tooth loss and replacement, weekly dental wax bites of 3 leopard geckos were taken over a 35-week period. The present/absent tooth positions were recorded. During the experimental period, the palate was injected bilaterally with NaCl (control) and then with LiCl. The geckos were to be biological replicates. Symmetry was analyzed with parametric tests (repeated measures ANOVA, Tukey’s post-hoc), while time for emergence and total absent teeth per week were analyzed with non-parametric tests (Kruskal-Wallis ANOVA, Mann-Whitney U post-hoc and Bonferroni Correction). The average replacement frequency was 6-7 weeks and posterior-to-anterior waves of replacement were formed. Right to left symmetry between individual tooth positions was high (>80%) when all teeth were included but dropped to 50% when only absent teeth were included. Two animals were followed for 14 weeks after NaCl injections and 14 weeks after LiCl injections. NaCl did not affect the replacement dentition but LiCl delayed and disrupted the pattern of replacement. The phenotypes were more severe for one animal including 1) increased time before emergence, 2) increased total number of absent teeth per week, 3) a greater effect on anterior teeth and 4) disruption of symmetry. The most affected period began 7 weeks post LiCl injection. At the end of the study, in vitro CT scans of both animals revealed normal patterns of unerupted teeth however there was bone loss in one animal. Gecko tooth replacement is rapid enough to be useful for longitudinal studies. Between-animal variation is high when studying individual teeth therefore each animal should be used as its own control. Future work includes increasing the biological replicates and detailed molecular studies to confirm the effect of LiCl.Dentistry, Faculty of
Graduate
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Ramirez, Edward A. "Gecko Digital Hyperextension: Kinematics, Surface Roughness and Locomotor Performance." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1333986580.
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Stark, Alyssa Yeager. "The Effect of Water on the Gecko Adhesive System." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1405334677.
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Hill, Ginel Corina. "Dual-axis MEMS force sensors for gecko adhesion studies /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Polakow, Daniel Adam. "Communication and sexual selection in the barking gecko (Ptenopus kochi)." Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/9511.
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Bibliography: leaves 167-206.This study focused on elucidating the functional significance of some aspects of the behaviour of Koch's barking gecko, Ptenopus kochi, during a field season conducted at the Desert Ecology Research Unit in Namibia for four months in 1995. Ptenopus kochi is a terrestrial species, and males were observed calling from their burrow entrances in the dry Kuiseb river bed during the hot summer months. First, aspects of competition among calling males were investigated. Calling males were seen to be non-randomly distributed relative to one another with evidence for regularity of spacing in dense aggregations. Sound intensity was investigated as the mechanism of spacing, and was mathematically modelled to gauge how the intensities of the calls of nearest-neighbour males overlapped. Results revealed a constancy at which neighbouring call intensities overlap, and playback experiments ratified the presence of a critical intensity threshold in the population, beyond which male tolerance broke down. These results suggested that spacing in P. kochi is vocally-mediated and that sound intensity acts as the proximate cue through which individuals gauge the closeness of neighbouring males. Second, the inter-relationships between call features of P. kochi's vocalisation, and how these features related to both intrinsic (morphological) and extrinsic (ambient) sources of variability were analytically explored. The principles of information theory and individual recognition by voice were used to gauge the variation manifest in the features of P. kochi's call. A novel statistical method for disentangling the influence of incidental sources of variation from 'signal' features in animal voices was developed. Results showed how once the predictable covariance in call structure was removed, the calls of P. kochi males were rendered statistically indistinguishable from one another. Several descriptor measures of P. kochi's vocalisation were seen to be highly dependent on meteorological determinants, as was nightly chorus duration. Lastly, mate-choice in P. kochi was explored using correlational evidence. Results revealed that mating success was closely linked to individual male differences in display effort and chorus site burrow activity, and less to morphological or territorial characteristics. Counter-intuitively, a positive relationship between call rate and chorus site residency was found in males, suggesting a possible role for classical condition-dependence in the evolution of female mate preference. Aspects of mate choice, together with the emergent importance of residency in this study were discussed and some ideas suggested for further research.
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Amaral, Paulo Alexandre Paixão. "Interface de instrumentos para veículo eléctrico Gecko: Merula - Redes sociais." Master's thesis, Universidade de Évora, 2011. http://hdl.handle.net/10174/12376.
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O principal objetivo deste trabalho e o desenvolvimento do painel de instrumentos
do ve culo el etrico Gecko Merula. Para tal, foi de nido um conjunto de princ pios
de apresenta c~ao de informa c~ao em ve culos e foi tamb em de nido, para a plataforma
Java e para a plataforma Android, um ambiente de desenvolvimento que permite
a de ni c~ao de pain eis de instrumentos de modo
ex vel. De forma a fazer uso
das liga c~oes sociais estabelecidas entre os utilizadores do Facebook foi de nida uma
aplica c~ao denominada Ve culoSocial que faz uso destas liga c~oes de forma a ltrar
conte udos de localiza c~ao num mapa. O ambiente de desenvolvimento de nido foi
testado numa plataforma teste, de forma a estudar o tempo de desenho dos componentes
no ecr~a. As interfaces do ve culo Gecko Merula e do Ve culoSocial foram
avaliadas com base nos princ pios de apresenta c~ao de informa c~ao em ve culos. A
partir dos testes de desempenho ao ambiente de desenvolvimento concluiu-se que,
para a plataforma de teste, o mesmo n~ao dever a de nir um n umero de componentes
demasiado elevado no painel de instrumentos de um ve culo, de forma a n~ao afetar
a precis~ao do painel. Da avalia c~ao das interfaces das aplica c~oes concluiu-se que e
necess aria a realiza c~ao de testes futuros nas interfaces e tamb em que a aplica c~ao
Ve culoSocial n~ao garante uma resposta atempada a um pedido de input de utilizador; ### Abstract:
The main goal for this work is the development of a dashboard for the electric
vehicle Gecko Merula. For this purpose, it was de ned a set of vehicle information
presentation principles and it was also de ned, for the Java platform and for the
Android platform, a development environment that produces in a
exible way a
vehicle dashboard. To make use of the social connections between users of Facebook,
it was de ned an application named Ve culoSocial that uses these social connections
in order to lter localization content to a map. The development environment was
tested, on a test platform, in order to study the drawing time of the components on
the screen. Gecko Merula and Ve culoSocial's interfaces were evaluated based on the
vehicle information presentation principles. From the performance tests performed
on the development environment it was concluded that, for the test platform, the
environment should not de ne an excessively high number of components on a vehicle
dashboard, so that it doesn't a ect the dashboard's precision. From the evaluation
of the applications' interface it was concluded that future interface tests are required
and that the Ve culoSocial application does not guarantee a timely response to a
user's input request.
15
Baker, Scott Michael. "Server Virtualization." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1388%5F1%5Fm.pdf&type=application/pdf.
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Klittich, Mena R. "Surface Interactions with Hierarchical Nanostructures: From Gecko Adhesion to Thermal Behavior." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1499440265902425.
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Xu, Quan. "Dynamic Adhesion and Self-cleaning Mechanisms of Gecko Setae and Spatulae." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407812/.
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Geckos can freely climb on walls and ceilings against their body weight at speed of over 1ms-1. Switching between attachment and detachment seem simple and easy for geckos, without considering the surface to be dry or wet, smooth or rough, dirty or clean. In addition, gecko can shed dirt particles during use, keeping the adhesive pads clean. Mimicking this biological system can lead to a new class of dry adhesives for various applications. However, gecko’s unique dry self-cleaning mechanism remains unknown, which impedes the development of self-cleaning dry adhesives. In this dissertation we provide new evidence and self-cleaning mechanism to explain how gecko shed particles and keep its sticky feet clean. First we studied the dynamic enhancement observed between micro-sized particles and substrate under dry and wet conditions. The adhesion force of soft (polystyrene) and hard (SiO2 and Al2O3) micro-particles on soft (polystyrene) and hard (fused silica and sapphire) substrates was measured using an atomic force microscope (AFM) with retraction (z-piezo) speed ranging over 4 orders of magnitude. The adhesion is strongly enhanced by the dynamic effect. When the retraction speeds varies from 0.02 µm/s to 156 µm/s, the adhesion force increases by 10% ~ 50% in dry nitrogen while it increases by 15%~70% in humid air. A dynamic model was developed to explain this dynamic effect, which agrees well with the experimental results. Similar dynamic enhancement was also observed in aqueous solution. The influence of dynamic factors related to the adhesion enhancement, such as particle inertia, viscoelastic deformations and crack propagation, was discussed to understand the dynamic enhancement mechanisms. Although particles show dynamic enhancement, Gecko fabrillar hair shows a totally different trend. The pull off forces of a single gecko seta and spatula was tested by AFM under different pull-off velocities. The result shows that both the spatula and the seta have a rate independent adhesion response in normal retraction, which is quite different from micro-particles. Further research indicated the shape of the contact area was a key factor to the dynamic effect. In order to verify this hypothesis, artificial gecko spatula made of glass fibers was nanofabricated by a focus ion beam (FIB) and tested by AFM. These manmade spatulae also show a rate independent adhesion response. The dynamic adhesion of a single gecko seta and spatula were simulated with finite element analysis and the results also confirm the rate independent phenomena.. In conclusion, self-cleaning is induced by dynamic effect during gecko locomotion. The relative dynamic adhesion change between particles and seta makes it possible for gecko to shed the dirt particles while walking.Finally, the fatigue property of gecko seta was examined with the atomic force microscope under cyclic attachment/detachment process, mimicking gecko running. The adhesion force versus cycles has been tested and evaluated. Fatigue mechanism of gecko seta was also analyzed based on the experimental findings.
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Huber, Gerrit. "Nanoscale adhesion of individual gecko spatulae explored by atomic force microscopy." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-25315.
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Tocher, Mandy Darlene. "The New Zealand common gecko Hoplodactylus maculatus: an ecophysiological comparsion of two isolated populations." Thesis, University of Canterbury. Biological Sciences, 1992. http://hdl.handle.net/10092/1431.
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Thermophysiological traits of two isolated Hoplodactylus maculatus populations were investigated to test adpatations to climate. Geckos were collected from Craigieburn (high altitude, generally cooler site) and Banks Peninsula. If climatic conditions at respective sites influenced physiology, I expected geckos from Craigieburn to exhibit cold-adapted physiological traits, whilst Banks Peninsula geckos would exhibit traits more characteristic of a warmclimate species. To this end I investigated four thermophysiological parameters: metabolism (SMR), preferred body temperature (PBT), locomotory performance and critical thermal minimum (CTMin). I hypothesized that if climate had an effect on SMR, Craigieburn geckos would exhibit higher levels of SMR which typically characterise other coolclimate reptiles. Craigieburn geckos displayed an average relative elevation of SMR over Banks Peninsula geckos of 26%. Furthermore, Craigieburn geckos appeared to be 'geared' towards lower body temperatures and exhibited a greater acclimatory and acclimatizatory ability of SMR. The PBT of Craigieburn geckos was consistently elevated above Banks Peninsula geckos. This finding was somewhat paradoxical in light of previous studies of this parameter. A closer examination of the ecology of the two populations is required to clarify the adaptive significance of a higher PBT in geckos from a cooler climate. With respect to locomotory performance, I hypothesized that if thermal extremes influenced activity, Craigieburn geckos would exhibit activity patterns which help ameliorate the adverse effects of cold temperature. Craigieburn geckos did in fact have greater independence of activity to temperature than Banks Peninsula geckos, especially over lower body temperatures. The final parameter investigated, that of the critical thermal minimum, failed to distinguish the populations decisively. However there was some evidence of a greater acclimatizatory and acclimatory range in Craigieburn geckos, providing somewhat limited support for a population difference. Investigations into all four parameters lead me to conclude that populations of Hoplodactylus maculatus from Craigieburn and Banks Peninsula are physiologically distinct and warrant a revision of nomenclature.
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Cafariello, Christopher. "The Identification of MTF2-specific Synthetic Lethal Interactions in Refractory Acute Myeloid Leukemia Using CRISPR." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39886.
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Acute myeloid leukemia (AML) is a disease characterized by overproduction of abnormally differentiated, hyper-proliferative myeloid cells known as blasts in bone-marrow and blood. Our laboratory has previously demonstrated that loss of epigenetic repression by the polycomb repressive complex 2 (PRC2), which is mediated by complex member metal response element binding transcription factor 2 (MTF2), drives chemo-resistance resulting in refractory AML. In this study, to identify MTF2-specific synthetic lethal interactions, a genome-scale CRISPR Knock-out (GeCKO) synthetic lethal screen was performed in matched MTF2-deficient and rescued THP-1 cells both in the absence and presence of the induction chemotherapeutic cytarabine. Following careful analysis of screening data using specialized software, 104 highly significant MTF2-specific synthetic lethal interactions as well as 15 cytarabine-specific synthetic lethal interactions were identified. Reduced stringency upon analysis helped to identify an additional seven MTF2-specific synthetic lethal interactions that could be targeted with commercially available small-molecule inhibitors. Among eight small molecule inhibitors, two DNA Polymerase A/Ribonucleotide Reductase Catalytic Subunit M1 (POLA/RRM1) dual inhibitors (clofarabine and fludarabine) were shown to induce toxicity with specificity for MTF2-deficient THP-1 cells at low concentrations only in the absence of cytarabine.
In the future, further testing of the therapeutic potential of clofarabine and fludarabine in treating MTF2-deficient AML will be conducted in patient derived bone-marrow aspirates which better represent the true clonal and hierarchical nature of this life-threatening malignancy. Furthermore, lentiviral delivery of short-hairpin RNAs (shRNAs) targeting highly significant, non-enzymatic MTF2 and cytarabine-specific synthetic lethal interactions will be performed in both THP-1 cells as well as in patient derived bone-marrow aspirates. Eventually, in vitro validated targets will be validated under in vivo conditions using a patient derived xenograft (PDX) preclinical animal model of AML using immunocompromised NOD scid gamma (NSG) mice.
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Blow, Nathan S. Belote John. "Molecular evolution of visual pigments of the Tokay gecko and bluefin killifish." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.
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Rong, Zhuxia. "Structure-property relations in nanostructured materials : from solar cells to gecko adhesion." Thesis, University of Cambridge, 2014. https://www.repository.cam.ac.uk/handle/1810/245291.
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This thesis explores the structure-property relations in different nanostructured materials. Nanostructured polymer blends with interpenetrating network morphology of donor and acceptor materials have been considered ideal for organic bulk heterojunction photovoltaics. In this work we mainly investigate the self-organization of polymer blends via crystallization to generate functional nanostructures for organic electronics. Controlling morphology of organic photovoltaic thin films is crucial for the optimization of the device performance as there is a fine balance of exciton generation and separation as well as charge transport. To better understand the bulk heterojunction morphology, we first investigated the structure formation of poly (3-hexylthiophene) (P3HT)/ phenyl-C61- butyric-acid methyl ester (PCBM) system. Crystallization-induced phase separation has been found to drive the formation of a nanostructure in the blends, the size of which is determined by the intrinsic 10 nm length scale of semicrystalline P3HT. The mixing of PCBM within amorphous P3HT interlayers does not disrupt the crystallinity of the P3HT. P3HT crystallization expels PCBM into the spherulitic interlamellar amorphous layers, where it enriches to its miscibility limit. Above the solubility limit, PCBM aggregates start to form. The results suggest that the crystallization of P3HT and the enrichment of PCBM in interlamellar regions give rise to interconnected donor and acceptor phases those are close to the optimal bulk heterojunction structure. This structure formation mechanism is manifested by the good photovoltaic performance of spherulitic P3HT/PCBM films. Structural studies of P3HT/poly[(9,9-dioctyfluorene)-2,7-diyl-alt-(4,7-bis(3-hexylthien-5- yl)-2,1,3-benzothiadiazole)-2', 2"-diyl] (F8TBT) are presented. P3HT/F8TBT system exhibits a crystallization-driven structure formation similar to the P3HT/PCBM system despite the existence of a miscibility gap. The lamellar crystallization of P3HT is not perturbed by the addition of F8TBT. X-ray scattering studies indicate that F8TBT is mixed in the interlamellar amorphous phase up to a solubility limit, while a bulk heterojunction framework is established by the crystalline lamellae of P3HT. The excess F8TBT is accommodated at amorphous grain boundaries as well as the film/substrate interface. The structural studies are correlated with the photovoltaic device performance of P3HT/F8TBT films which exhibit spherulitic morphology. Devices based on spherulitic films show moderate efficiencies with improved fill factors but decreased photocurrents in comparison to that of thermal annealing condition. The results suggest that the nanostructure formation in P3HT/F8TBT blends is determined by the crystallization of P3HT, resulting in a structural size that are beneficial for exciton dissociation, while the F8TBT segregation at the substrate interface impair the device performance. The phase separation behavior in crystalline/crystalline blends consisting of P3HT and polyethylene oxide (PEO) is investigated. The self-assembly of P3HT in solution induces vertical segregation in blend films, in comparison to typical lateral polymer phase separation structures from non-aggregated solutions. Thin film transistors based on P3HT/PEO blends show show a nearly undegraded charge carrier mobility at low P3HT content due to the formation of a layered structure with P3HT nanowire networks segregated at the dielectric surface. Finally, a diversion from morphology studies of polymer blends involves the biomimetic fabrication of hierarchical fibrillar structures to achieve gecko adhesion. The hierarchical structures were fabricated based on polymer pillars tipping with carbon nanotube forests. The adhesion performance of the polymer-carbon nanotube hierarchical structures was tested by shear force measurements.
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Tejangkura, Thanawan. "Hybrid zone genetics and within-island diversity of the gecko Tarentola boettgeri." Thesis, Liverpool John Moores University, 2012. http://researchonline.ljmu.ac.uk/6162/.
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This study builds on a previous study that demonstrates the existence of deep mitochondrial lineages in the gecko Tarentola boettgeri within Gran Canaria (Gubitz et al. 2005). Here, I identified and analyzed the area where the two most divergent mitochondrial •lineages meet. The primary aim was to examine how geographical structuring of mtDNA has been maintained after secondary contact. MtDNA analyses used a 608 basepair fragment of the cytochrome b (cyt b) gene from 389 individuals sampled from 14 populations along a 32 km southeast (SE) transect across Gran Canaria. It revealed a low degree of mtDNA admixture and negligible gene flow across the contact zone. This led to the hypothesis that reproductive barriers may have formed between populations from different mtDNA lineages. Analyses of seven body dimension and scalation characters revealed that spatial patterns of morphological changes were not associated with the transition in mtDNA lineage frequency across the transect. This contrasted with another lizard species on the same island, Chalcides sexlineatus, in which phylogeography and morphology are highly correlated. This study identified ten unique microsatellite markers in T. boettgeri. Like morphology, analyses of these microsatellites did not reveal a pronounced spatial pattern of differentiation in the nuclear genome. These results appear to reject the hypothesis of a physical or genetic barrier to reproduction. Studies of micro satellites also suggested that T. boettgeri is a low dispersal species and this might explain the persistence of mtDNA contact zone. However, evidence of concordant spatial patterns between divergence in the nuclear genome and morphology was detected. The discordant spatial patterns of mitochondrial and nuclear genotype frequencies do not appear to be explained by sex-biased gene flow, and are difficult to understand because of expected interactions between the two genomes. Thus, further investigation is suggested to allow clarification of the causes of mito-nuclear discordance in T. boettgeri.
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Gomez, Patricia A. "Microhabitat preference of the introduced gecko Hemidactylus turcicus in an urban environment." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001213.
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Caven, Barnaby. "Exploring a textile route to mimicking the adhesion properties of the gecko foot." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536107.
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Song, Sukho. "Soft Robotic Grippers Using Gecko-Inspired Fibrillar Adhesives for Three-Dimensional Surface Grasping." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/936.
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Researches on biological adhesive systems in nature have changed a perspective view on adhesion that it is not only the area of surface chemistry, but also mechanics of interfacial geometry which can significantly effect on fracture strength and load distribution on the contact interface. Various synthetic fibrillar adhesives in previous works have shown enhanced interfacial bond strength with the capacity of adhesion control by exploiting mechanical deformation of the elastomeric fibrillar structures inspired by geckos. However, control of the interfacial load distribution has been focused on the size of micro-contact with single or a few of micro-/nano-fibers on planar surface, and not for a large contact area on complex three-dimensional (3D) surfaces. This thesis work aims at investigating principles of the interfacial load distribution control in multi-scale, ranging from micro-contact with single micro-fiber to a centimeter-scale contact with a membrane-backed micro-fiber array on non-planar 3D surfaces. The findings are also applied for developing a soft robotic gripper capable of grasping a wide range of complex objects in size, shape, and number, expanding the area of practical applications for bio-inspired adhesives in transfer printing, robotic manipulators, and mobile robots. This paper comprises three main works. First, we investigate the effect of tip-shapes on the interfacial load sharing of mushroom-shaped micro-fibrillar adhesives with precisely defined tipgeometries using high resolution 3D nano-fabrication technique. For a large area of non-planar contact interface, we fabricate fibrillar adhesives on a membrane (FAM) by integrating micro-fibers with a soft backing, which enables robust and controllable adhesion on 3D surfaces. Picking and releasing mechanism for the maximal controllability in adhesion are discussed. Finally, we propose a soft robotic architecture which can control the interfacial load distribution for the FAM on 3D surfaces, solving an inherit dilemma between conformability and high fracture strength with the equal load sharing on complex non-planar 3D surfaces.
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Gualdino, Miguel Ângelo da Silva. "Interface de instrumentos para veículo eléctrico Gecko Merula - sistema de navegação por satélite." Master's thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/12200.
Full textAbstract:
O objetivo deste trabalho e o desenvolvimento de um painel de instrumentos para o
ve culo el etrico Gecko Merula. Para o seu desenvolvimento foi feito um levantamento
de princ pios para de ni c~ao do painel de instrumentos. O painel de instrumentos foi
desenvolvido na plataforma Java para de ni c~ao dos instrumentos presentes no painel
de instrumentos. Foi desenvolvido um ambiente de desenvolvimento para cria c~ao de
interfaces gr a cas de nidas no documento XML. De forma a complementar o painel
de instrumentos foi desenvolvida um sistema de navega c~ao por sat elite que faz uso
da localiza c~ao do ve culo para c alculo de itiner arios para um determinado destino
com base em mapas online. As interfaces propostas foram avaliadas pelos princ pios
de apresenta c~ao de informa c~ao em ve culos e pelo tempo de desenho, mem oria consumida
da interface do painel de instrumentos e do sistema de navega c~ao. Com base
nos resultados obtidos conclui-se que o painel de instrumentos n~ao dever a conter
demasiados componentes pois prejudicar a a aten c~ao do condutor e eventualmente a
velocidade de atualiza c~ao dos valores apresentados no painel. O painel de instrumentos
proposto permite de nir e alterar os v arios componentes gr a cos no documento
XML de forma
ex vel; ### Abstract:
The objective of this work is the development of an instrument panel for the electric
vehicle Gecko Merula. A survey of principles for setting the instrument panel was
done for its development. The instrument panel was developed on the Java platform.
It was implemented a development environment to create a graphical user
interfaces speci ed in the XML document. In order to complement the instrument
panel a satellite navigation system has been developed. This system makes use of
the vehicle's location to calculate itineraries to a particular destination based on
online maps. The proposed interface was evaluated by: principles of presentation
of information in vehicles; and drawing time; memory consumption of the interface
of the instrument panel and navigation system. Based on the achieved results it
was concluded that the instrument panel should not include too many components
because it may prejudice the driver's attention and the accuracy of the values presented
on the panel. This proposed instrument panel allows the designers to set and
change the various graphical components on the XML document in a
exible way.
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Sakai, Osamu. "Personality of a clonal gecko Lepidodactylus lugubris: developmental mechanism and relation to microhabitat use." Kyoto University, 2019. http://hdl.handle.net/2433/242641.
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Hu, Shihao. "Gecko and Bio-Inspired Hierarchical Fibrillar Adhesive Structures Explored by Multiscale Modeling and Simulation." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1337148595.
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Ginebre, Emmanuel. "Geometry-dependence of the adhesive strength of biomimetic, micropatterned surfaces." Thesis, Linköpings universitet, Mekanik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81067.
Full textAbstract:
Pressure sensitive adhesive surfaces are often inspired by nature. Miming the toe-surface of gecko, engineered surfaces made of thousands of micro-pillars show promising adhesive properties. This surfaces, covered with cylindrical pillars arranged into a pattern have adhesive properties greatly dependent on the geometrical characteristics. In this thesis, have been studied successively two models of micro-patterned surfaces, one two-dimensional, the other in three-dimensional using a FEM tool. Varying geometry parameters, has been determined optimal geometries to improve adhesive strength on these biomimetic, micropatterned surfaces. This study concludes to the non-adaptability of one-level scale micropatterned surface to large area of adhesion, to the strong advantage from the point of adhesion per contact area for high aspect ratio at each level of the geometry and study the opportunity of hierarchical structures. Some further suggestions of improvements to adhesion properties are discussed in the final chapter.
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Buehler, Betul. "Molecular Adhesion and Friction at Elastomer/Polymer Interfaces." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1164649632.
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Allemang, Ashley Jane. "A genetic basis for ecologically relevant behavior in the invasive mourning gecko Lepidodactylus lugubris." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1212173329.
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Rhen, Turk Eleazar. "Effects of embryonic temperature, gonadal sex, and sex steroids on behavior and neuroendocrine phenotype in leopard gecko, Eublepharis macularius /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Abusomwan, Uyiosa Anthony. "Mechanics of Adhesion and Contact Self-Cleaning of Bio-Inspired Microfiber Adhesives." Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/449.
Full textAbstract:
The remarkable attachment system of geckos has inspired the development of dry microfiber adhesives through the last two decades. Some of the notable characteristics of gecko-inspired fibrillar adhesives include: strong, directional, and controllable adhesion to smooth and rough surfaces in air, vacuum, and under water; ability to maintain strong adhesion during repeated use; anti-fouling and self-cleaning after contamination. Given these outstanding qualities, fibrillar adhesives promise an extensive range of use in industrial, robotic, manufacturing, medical, and consumer products. Significant advancements have been made in the design of geckoinspired microfiber adhesives with the characteristic properties listed above, with the exception of the anti-fouling and self-cleaning features. The self-cleaning mechanism of the gecko’s adhesion system plays an important role to its ability to remain sticky in various environments. Similarly, enabling self-cleaning capability for synthetic microfiber adhesives will lead to robust performance in various areas of application. Presently, the practical use of fibrillar adhesives is restricted mainly to clean environments, where they are free from contaminants. The goal of this thesis is to conduct a detailed study of the mechanisms and mechanics of contact-based self-cleaning of gecko-inspired microfiber adhesives. This work focuses on contact self-cleaning mechanisms, as a more practical approach to cleaning. Previous studies on the cleaning of microfiber adhesives have mostly focused on mechanisms that involve complete removal of the contaminants from the adhesive. In this thesis, a second cleaning process is proposed whereby particles are removed from the tip of the microfibers and embedded between adjacent microfibers or in grooves patterned onto the adhesive, where they are no longer detrimental to the performance of the adhesive. In this work, a model of adhesion for microfiber adhesives that take the deformation of the backing layer under individual microfiber is developed. The dependence of adhesion of microfiber adhesives on the rate of unloading is also modeled and verified using experiments. The models of adhesion presented are later used to study the mechanics of contact self-cleaning of microfiber adhesives. Three major categories of self-cleaning are identified as wet self-cleaning, dynamic self-cleaning, and contact self-cleaning. A total of seven self-cleaning mechanisms that are associated with these categories are also presented and discussed. Results from the self-cleaning model and experiments show that shear loading plays an important role in self-cleaning. The underlying mechanism of contact self-cleaning due to normal and shear loading for spherical contaminants is found to be the particle rolling between the adhesive and a contacted substrate. Results from the model and experiments also show that small microfiber tips (much less than the size of the contaminants) are favorable for self-cleaning. On the other hand, large microfiber tips (much larger than the size of the contaminants) are favorable for anti-fouling of the microfiber adhesive. Results from this work suggests that the sub-micrometer size of the gecko’s adhesive fibers and the lamellae under the gecko toes contribute to its outstanding self-cleaning performance. The results presented in this thesis can be implemented in the design of microfiber adhesives with robust adhesion, self-cleaning and anti-fouling characteristic, for use in numerous applications and in various environments.
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Sayer, Robert A. "Surface construction and mechanisms of adhesion in tokay gecko feet and characterization of a bio-inspired reversible adhesive tape." Connect to resource, 2006. http://hdl.handle.net/1811/6438.
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Thesis (Honors)--Ohio State University, 2006.Title from first page of PDF file. Document formatted into pages: contains vii, 71 p.; also includes graphics. Includes bibliographical references (p. 61-67). Available online via Ohio State University's Knowledge Bank.
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Huber, Gerrit [Verfasser]. "Nanoscale adhesion of individual gecko spatulae explored by atomic force microscopy / Institut für Metallkunde der Universität Stuttgartt ... Vorgelegt von Gerrit Huber." Stuttgart : Max-Planck-Inst. für Metallforschung, 2006. http://d-nb.info/979720664/34.
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Vídeňský, Martin. "Mozilla jako vývojová platforma." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235880.
Full textAbstract:
This thesis deals with introduction of Mozilla as a development platform. Thesis is divided into four parts. The first one consists of a theoretical introduction, which describes architecture, the most important technologies and motivation for usage of Mozilla as a development platform. The second part leads step by step threw making own project. The third part is dedicated to description of the example application Tester. Tester is an e-learning project designed for easier learning process with scope on vocabulary practise. In the conclusion of thesis, there is the evaluation of Mozilla platform based on practical experience.
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Bishop, Joanna Kelly. "Predictable feeding in zoos : research methods and behavioural effects." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1580.
Full textAbstract:
The behaviour of zoo animals can come to anticipate temporally predictable feeding times. However, there is a lack of consensus over the effects of such routines on behaviour and welfare. Few studies have been published in this area, perhaps in part due to methodological challenges. The current programme of work therefore aimed to extend knowledge on the effect of predictable feeding routines, and to develop a suitable methodology to overcome challenges. Prior to predictable feeding, tigers showed patterns of increased ‘active’ behaviours such as locomotion and pacing, and decreased inactivity. Geckos also showed increased ‘active’ behaviours such as locomotion and ‘stationary but moving head’ prior to predictable, compared to unpredictable feeding times, with significant differences between conditions (RSS = 0.059 and 0.047, p < .05). However, anticipatory patterns were not demonstrated for meerkats, which highlighted that other environmental factors may affect an animal’s response to temporal predictability (such as obtaining other food during the day, or signalled predictability). Studying patterns of behavioural change over time requires long periods of observation which is often not possible for researchers. The current programme of work argues that a measure which can be reliably used by many, relatively untrained observers is necessary to study predictability. The measure of ‘busyness’, a subjective rating of animal behaviour, was tested for reliability and validity. Busyness ratings showed good inter-observer reliability (ICC > .72) and correlated with traditional measures of behaviour. Busyness ratings demonstrated clear patterns related to feeding time and gave a useful compound measure of behavioural change. The use of multiple observers was extended to a citizen science approach, where useful data on anticipation in fish were obtained from aquarium visitors using a touch screen. The current programme of work successfully investigated the effects of predictable feeding routines on patterns of animal behaviour, alongside the development of suitable methods. The qualitative techniques developed here offer potential to increase the data obtained in future research into predictability and many other topics.
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Hays, Brenton J., Joseph R. Bidwell, and Drew E. Dittmer. "An Assessment of Thermal Preference of Two Species of Knob-tailed Geckos, Nephrurus levis and N. laevissimus, at Uluru Kata-Tjuta National Park." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/7195.
Full textAbstract:
Nocturnal lizards are often active at temperatures that are sub-optimal for physiological functioning, a phenomenon that has been referred to as the ‘nocturnal paradox’. The purpose of this study was to investigate the general habitat and thermal preference of two species of nocturnal gecko in the genus Nephrurus with a focus on differences between preferred body temperatures determined under laboratory conditions and those measured in animals at the time of field collection. The Smooth Knob-tailed gecko (Nephrurus levis) and the Pale Knob-tailed Gecko (N. laevissimus) inhabit the desert environment of Uluru Kata-Tjuta National Park in the Northern Territory of Australia. Habitat preferences were determined by documenting capture locations for these species while thermal preferences were determined using laboratory-based thermal gradients. Analysis of habitat use demonstrated a significant difference in habitat preference between the two species. Nephrurus levis was most often in Spinifex sandplain and mulga shrubland and N. laevissimus was most often found around sand dune habitats. Fieldactive body temperatures of both species ranged from 14.5 °C to 32.2 °C and were significantly correlated with air and ground temperature at the time of capture. The thermal preference (Tpref) of N. levis (mean day Tpref mid = 29.1 °C and mean night Tpref 24 = 28.2 °C, n = 19) and N. laevissimus (mean day Tpref mid = 29.5 °C and mean night Tpref 24 = 27.8 °C, n = 27) were not significantly different, although both species exhibited significantly higher daytime and night-time preferred body temperatures than body temperatures observed in the field. Body size did not affect thermal preference for either species. As such, the thermal preferences of these species support the concept of the nocturnal paradox. Additionally, it has been suggested that the characteristic swollen tail tip displayed by all Nephrurus species may play a role in assessing the thermal environment. While not investigated extensively here, combined data for both species demonstrated that individuals oriented their tail toward the heat source in thermal gradients significantly more than expected if orientation were random.
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Bannock, Carol A. "Implications of past and future vegetation change for the lizard fauna of Motunau Island." Master's thesis, Lincoln University. Bio-Protection and Ecology Division, 1998. http://theses.lincoln.ac.nz/public/adt-NZLIU20080430.163408/.
Full textAbstract:
Abundance, distribution and habitat preferences of the lizard species present on Motunau Island, off the Canterbury coast of New Zealand, were investigated. The aim of the study was to investigate the extent to which recent vegetation change on Motunau Island has effected the lizard community and what implications this has for the future management of the Island. Three species of lizard occur on Motunau Island; the common gecko (Hoplodactylus maculatus), common skink (Oligosoma nigriplantare polychroma) and spotted skink (O. lineoocellatum). Rabbits (Oryctolagus cuniculus) were present on the island from 1862 until their eradication in 1962. Since then, vegetation on the island has changed from being tussock-dominated to being dominated by exotic weeds. Data from lizard pitfall trap surveys carried out in 1967-75 by Tony Whitaker of the Department of Scientific and Industrial Research (DSIR) were compared with new pitfall trapping data to determine if changes in the lizard population had occurred in response to these vegetation changes. The abundance of O. n. polychroma and H. maculatus does not appear to change significantly. The distribution of these two species were significantly correlated but neither showed any preference for a particular type. The abundance of O. lineoocellatum was significantly greater in 1996/97 than in the earlier DSlR surveys. This could be a result of the vegetation becoming more open and more structurally complex since the early surveys. This would offer greater opportunities for O. lineoocellatum (which is strongly heliothermic) to thermoregulate and forage. O. lineoocellatum showed no consistent significant preference towards any habitat type, although they tended to be found more in 'margin' habitat. Research into pitfall trapping and the way lizard behaviour may influence pitfall trapping data needs to be undertaken as there is a possible trap bias in this study. Management of Motunau Island needs to ensure that a structurally complex environment is maintained to ensure high numbers of all three lizard species can continue to coexist.
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Sethi, Sunny. "Carbon Nanotube Based Functional Superhydrophobic Coatings." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1271346171.
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Al-Amri, Issa Sulaiman Said. "Reproductive cycle of the house gecko, Hemidactylus flaviviridis, in Oman in relation to morphological and ultrastructural changes and plasma steroid concentrations with reference to localisation of progesterone receptors." Thesis, University of Portsmouth, 2012. https://researchportal.port.ac.uk/portal/en/theses/reproductive-cycle-of-the-house-gecko-hemidactylus-flaviviridis-in-oman-in-relation-to-morphological-and-ultrastructural-changes-and-plasma-steroid-concentrations-with-reference-to-localisation-of-progesterone-receptors(fd26f7ff-7aa4-4e66-b7bd-2bedd1cade9a).html.
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In Oman, a comprehensive study of the annual reproductive cycles of male and female house geckos, Hemidactylus flaviviridis was conducted. Circulating testosterone (T), oestradiol (E2) and progesterone (P) concentrations were measured using a sensitive HPLC-MS/MS detection technique. Data were collected from a natural population over two consecutive seasons. The annual patterns of circulating concentrations of T, E2 and P were measured for both sexes. In males, peak plasma T, E2 and P concentrations occurred in the active phase, coinciding with the stages of spermatogenesis, courtship and mating, but gradually declined in the second half of the mating period with a significant drop in the quiescent phase, coinciding with testicular regression. In females, elevated plasma E2 and T concentrations in the active phase were associated with vitellogenesis and mating. Plasma E2 concentrations decreased significantly during the quiescent phase, coinciding with follicular regression. Plasma P concentrations were elevated during gravidity but fell significantly prior to oviposition. The plasma steroid concentrations were related to the steroidogenic ultrastructural features and expression of progesterone receptors (PR) throughout the reproductive cycle. The steroidogenic ultrastructural features were characterized by the presence of smooth endoplasmic reticulum (SER) in the form of cisternal whorls and tubular cisternae, presence of swollen vesiculated mitochondria and association between SER, mitochondria, and lipid droplets. In the male, the rise in the three plasma steroid concentrations during the active phase was closely associated with the development of the ultrastructural features and strong PR expression in Leydig and Sertoli cells. During the quiescent phase, there was a significant decline in plasma steroid concentrations, undeveloped steroidogenic features and weakly expressed PR. In the female, the appearance of the steroidogenic ultrastructural features in the preovulatory and lutein granulosa cells was correlated with the significant rise in the three steroid concentrations and the strong expression of PR. As the steroid concentrations declined, the granulosa cells underwent general degeneration and disruption of the ultrastructural steroidogenic features. These detailed findings are the first to be reported for this species in the Arabian Peninsula. Based on histological and gross morphological observations, the house gecko ovulates two eggs at a time, one from each ovary. This is followed by a second two egg clutch, suggesting that this species lays two clutches of eggs annually, each clutch containing two eggs. The comprehensive data obtained from this study may be of some value for comparison with reproductive cycles of other closely related species in this region. In addition, conservation awareness for the protection of this widely distributed species may be beneficial for the protection of other wildlife.
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Valdez, Ridoutt Fernando Javier. "“Dinámica y estructura poblacional de Phyllodactylus sentosus Dixon & Huey, 1970, en la Huaca Pucllana-Lima, Perú”." Bachelor's thesis, Universidad Ricardo Palma, 2016. http://cybertesis.urp.edu.pe/handle/urp/847.
Full textAbstract:
El gecko, Phyllodactylus sentosus, es endémico del Perú y el único miembro de la Familia Phyllodactylidae considerado amenazado por las leyes peruanas. Se conoce su distribución principalmente por subpoblaciones en siete sitios arqueológicos, aislados entre sí, dentro de la ciudad de Lima. Se analizó la dinámica y estructura poblacional de P. sentosus en la Huaca Pucllana, ubicada en el distrito de Miraflores, Lima, a través de evaluaciones mensuales de captura y recaptura. Se marcaron, midieron e identificaron hembras, machos y juveniles. La población varió estacionalmente y la estructura por clases de tamaño no siguió una distribución normal, la mayor parte de los organismos fueron juveniles y se distribuyeron en las clases de menor tamaño, los adultos presentaron una mayor dispersión y en todos los meses evaluados se registraron hembras, machos y juveniles. Las hembras fueron significativamente más grandes que los machos, por lo que existe dimorfismo sexual de tamaño. La temporada de reproducción fue de noviembre a febrero y de febrero a marzo se dieron la mayor cantidad de nacimientos. P. sentosus mostró una proporción de sexual de 1(♀) : 0,9(♂). Los resultados de este estudio muestran aspectos importantes sobre la historia de vida de P. sentosus, proveyendo información útil para la toma de decisiones sobre el manejo y conservación de esta especie amenazada.The gecko, Phyllodactylus sentosus, is endemic to Peru and is the only member of the family Phyllodactylidae which is deemed threatened under the Peruvian legislation. Its distribution is mainly known in the form of subpopulations in seven separate archaeological sites, not connected with one another, within the city of Lima. The population dynamics and structure of P. sentosus were analyzed in the Huaca Pucllana, a pre-Incan temple, located in the Miraflores district in Lima. The analysis comprised monthly assessments of capture and recapture. Female, male and juvenile geckos were marked, measured and identified. The population varied on a seasonal basis and the size class structure did not follow a normal distribution. Most organisms were juvenile and distributed into the lower size classes. The adults presented a greater spread. Throughout the months of the assessment, females, males and juvenile geckos were recorded. The females were significantly larger than males. Therefore, there is sexual dimorphism in size. The mating season occurred from November through February and most births took place from February through March. P. sentosus showed a sex rate of 1(♀) : 0,9(♂). The results of this study feature important aspects in regard to the life history of P. sentosus, providing useful information for the decision making about the management and conservation of this threatened species.
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Aquino, Andrea. "GECO." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2390/.
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Snyder, Joshua P. "The autecology of Rhacodactylus auriculatus a natural history study of gargoyle geckos /." Click here for download, 2007. http://proquest.umi.com/pqdweb?did=1331400641&sid=1&Fmt=2&clientId=3260&RQT=309&VName=PQD.
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Bräuer, Peter. "Extension and application of a tropospheric aqueous phase chemical mechanism (CAPRAM) for aerosol and cloud models." Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-183743.
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The ubiquitous abundance of organic compounds in natural and anthorpogenically influenced eco-systems has put these compounds into the focus of atmospheric research. Organic compounds have an impact on air quality, climate, and human health. Moreover, they affect particle growth, secondary organic aerosol (SOA) formation, and the global radiation budget by altering particle properties. To investigate the multiphase chemistry of organic compounds and interactions with the aqueous phase in the troposphere, modelling can provide a useful tool. The oxidation of larger organic molecules to the final product CO2 can involve a huge number of intermediate compounds and tens of thousands of reactions. Therefore, the creation of explicit mechanisms relies on automated mechanism construction. Estimation methods for the prediction of the kinetic data needed to describe the degradation of these intermediates are inevitable due to the infeasibility of an experimental determination of all necessary data. Current aqueous phase descriptions of organic chemistry lag behind the gas phase descriptions in atmospheric chemical mechanisms despite its importance for the multiphase chemistry of organic compounds. In this dissertation, the gas phase mechanism Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) has been advanced by a protocol for the description of the oxidation of organic compounds in the aqueous phase. Therefore, a database with kinetic data of 465 aqueous phase hydroxyl radical and 129 aqueous phase nitrate radical reactions with organic compounds has been compiled and evaluated. The database was used to evaluate currently available estimation methods for the prediction of aqueous phase kinetic data of reactions of organic compounds. Among the investigated methods were correlations of gas and aqueous kinetic data, kinetic data of homologous series of various compound classes, reactivity comparisons of inorganic radical oxidants, Evans-Polanyi-type correlations, and structure-activity relationships (SARs). Evans-Polanyi-type correlations have been improved for the purpose of automated mechanism self-generation of mechanisms with large organic molecules. A protocol has been designed based on SARs for hydroxyl radical reactions and the improved Evans-Polanyi-type correlations for nitrate radical reactions with organic compounds. The protocol was assessed in a series of critical sensitivity studies, where uncertainties of critical parameters were investigated. The advanced multiphase generator GECKO-A was used to generate mechanisms, which were applied in box model studies and validated against two sets of aerosol chamber experiments. Experiments differed by the initial compounds used (hexane and trimethylbenzene) and the experimental conditions (UV-C lights off/on and additional in-situ hydroxyl radical source no/yes). Reasonable to good agreement of the modelled and experimental results was achieved in these studies. Finally, GECKO-A was used to create two new CAPRAM version, where, for the first time, branchingratios for different reaction pathways were introduced and the chemistry of compounds with up to four carbon atoms has been extended. The most detailed mechanism comprises 4174 compounds and 7145 processes. Detailed investigations were performed under real tropospheric conditions in urban and remote continental environments. Model results showed significant improvements, especially in regard to the formation of organic aerosol mass. Detailed investigations of concentration-time profiles and chemical fluxes refined the current knowledge of the multiphase processing of organic compounds in the troposphere, but also pointed at current limitations of the generator protocol, the mechanisms created, and current understanding of aqueous phase processes of organic compoundsDas zahlreiche Vorkommen organischer Verbindungen in natürlichen und anthropogen beeinflussten Ökosystemen hat diese Verbindungen in den Fokus der Atmosphärenforschung gerückt. Organische Verbindungen beeinträchtigen die Luftqualität, die menschliche Gesundheit und das Klima. Weiterhin werden Partikelwachstum und -eigenschaften, sekundäre organische Partikelbildung und dadurch der globale Strahlungshaushalt durch sie beeinflusst. Um die troposphärische Multiphasenchemie organischer Verbindungen und Wechselwirkungen mit der Flüssigphase zu untersuchen, sind Modellstudien hilfreich. Die Oxidation großer organischer Moleküle führt zu einer Vielzahl an Zwischenprodukten. Der Abbau erfolgt in unzähligen Reaktionen bis hin zum Endprodukt CO2. Bei der Entwicklung expliziter Mechanismen muss deshalb für diese Verbindungen auf computergestützte, automatisierte Methoden zurückgegriffen werden. Abschätzungsmethoden für die Vorhersage kinetischer Daten zur Beschreibung des Abbaus der Zwischenprodukte sind unabdingbar, da eine experimentelle Bestimmung aller benötigten Daten nicht realisierbar ist. Die derzeitige Beschreibung der Flüssigphasenchemie unterliegt deutlich den Beschreibungen der Gasphase in atmosphärischen Chemiemechanismen trotz deren Relevanz für die Multiphasenchemie. In dieser Arbeit wurde der Gasphasenmechanismusgenerator GECKO-A (“Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere”) um ein Protokoll zur Oxidation organischer Verbindungen in der Flüssigphase erweitert. Dazu wurde eine Datenbank mit kinetischen Daten von 465 Hydroxylradikal- und 129 Nitratradikalreaktionen mit organischen Verbindungen angelegt und evaluiert. Mit Hilfe der Datenbank wurden derzeitige Abschätzungsmethoden für die Vorhersage kinetischer Daten von Flüssigphasenreaktionen organischer Verbindungen evaluiert. Die untersuchten Methoden beinhalteten Korrelationen kinetischer Daten aus Gas- und Flüssigphase, homologer Reihen verschiedener Stoffklassen, Reaktivitätsvergleiche, Evans-Polanyi-Korrelationen und Struktur-Reaktivitätsbeziehungen. Für die Mechanismusgenerierung großer organischer Moleküle wurden die Evans-Polanyi-Korrelationen in dieser Arbeit weiterentwickelt. Es wurde ein Protokol für die Mechanismusgenerierung entwickelt, das auf Struktur-Reaktivitätsbeziehungen bei Reaktionen von organischen Verbindungen mit OH-Radikalen und auf den erweiterten Evans-Polanyi-Korrelationen bei NO3-Radikalreaktionen beruht. Das Protokoll wurde umfangreich in einer Reihe von Sensitivitätsstudien getestet, um Unsicherheiten kritischer Parameter abzuschätzen. Der erweiterte Multiphasengenerator GECKO-A wurde dazu verwendet, neue Mechanismen zu generieren, die in Boxmodellstudien gegen Aerosolkammerexperimente evaluiert wurden. Die Experimentreihen unterschieden sich sowohl in der betrachteten Ausgangssubstanz (Hexan und Trimethylbenzen) und dem Experimentaufbau (ohne oder mit UV-C-Photolyse und ohne oder mit zusätzlicher partikulärer Hydroxylradikalquelle). Bei den Experimenten konnte eine zufriedenstellende bis gute Übereinstimmung der experimentellen und Modellergebnisse erreicht werden. Weiterhin wurde GECKO-A verwendet, um zwei neue CAPRAM-Versionen mit bis zu 4174 Verbindungen und 7145 Prozessen zu generieren. Erstmals wurden Verzweigungsverhältnisse in CAPRAM eingeführt. Außerdem wurde die Chemie organischer Verbindungen mit bis zu vier Kohlenstoffatomen erweitert. Umfangreiche Untersuchungen unter realistischen troposphärischen Bedingungen in urbanen und ländlichen Gebieten haben deutliche Verbesserungen der erweiterten Mechanismen besonders in Bezug auf Massenzuwachs des organischen Aerosolanteils gezeigt. Das Verständnis der organischen Multiphasenchemie konnte durch detaillierte Untersuchungen zu den Konzentrations-Zeit-Profilen und chemischen Flüssen vertieft werden, aber auch gegenwärtige Limitierungen des Generators, der erzeugten Mechanismen und unseres Verständnisses für Flüssigphasenprozesse organischer Verbindungen aufgezeigt werden
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Moyer, Robert Walter. "Comparative morphological and biochemical study of the pineal complex in geckos /." Title page, abstract and contents only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phm938.pdf.
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Geneva, Anthony Joseph. "A phylogeographic analysis of Bavayia cf. crassicollis." Click here for download, 2007. http://proquest.umi.com/pqdweb?did=1428838771&sid=1&Fmt=2&clientId=3260&RQT=309&VName=PQD.
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Holmes, Scott. "Analysis of tooth replacement in adult leopard geckos." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44626.
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Though most dentate vertebrates replace their teeth at least once in the course of their lives, the process of tooth replacement is poorly understood. This is mainly because the major tooth development model is the mouse which only has one generation of teeth. Our previous work suggested that tooth renewal in geckos might involve dental epithelial stem cells and that these putative stem cells become transit- amplifying cells when exposed to canonical WNTs. Here we further investigate this idea using adult leopard geckos (Eublepharis macularius). To further previous findings from our lab that the dental apparatus is a WNT responsive tissue we perturbed the WNT pathway by agonist and antagonist organ cultures of oral tissue explants. BIO stimulated proliferation at an intermediate concentration of 20 μM but not at higher or lower concentrations. This suggests that in vivo, cells are responding to gradients of WNT activity. We also looked at associated BMP and FGF pathways via in situ histology and organ culture manipulation respectively and found alternating patterns of gene expression. We then mapped areas of high canonical WNT signaling and found that nuclear staining for phospho beta catenin was principally found in the outer enamel epithelium and successional lamina. We moved to an in vivo strategy to allow for better tissue survival. Palatal injections of LiCl or the control reagent NaCl were delivered to the base of the maxillary teeth. We found that LiCl increased proliferation in the successional lamina and cervical loops, areas that normally have higher proliferation. We conclude that certain regions of the dental epithelium are sensitive to change in canonical WNT signaling and that this signaling is potentially kept to a localized region via BMP inhibition of the WNT pathway. Regions of the dental lamina that contain putative stem cells may require signals in addition to WNTs to stimulate the formation of transit amplifying cells. Future work will further elucidate the many signaling cascades required for tooth succession to occur.
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Buckland, Jack Dany Steeves. "Status, ecology and conservation of endemic geckos in Mauritius." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.653090.
Full textAbstract:
In the past 400 years, there has been a drastic decline in the number of endemic species on mainland Mauritius, with the island losing 69% of its original reptile community. Of 17 endemic species, only five mostly Phelsuma species survived the human mediated disturbances on mainland Mauritius. These remaining arboreal endemic geckos still play important ecological roles in the Mauritian ecosystem. However, habitat fragmentation and introduction of invasive species have increased the threats to these endemic geckos. The recent invasion of the bigger Phelsuma grandis (giant Madagascar day gecko) has increased the threats posed to the existence of endemic geckos, while habitat loss and fragmentation is also playing a major role in gecko decline, particularly for Phelsuma guimbeaui (lowland forest day gecko). In this thesis, I studied the ecological effects of P. grandis on endemic geckos at a landscape and local scale using species .distribution and binomial mixture models. I also designed markers from microsatellite and mitochondrial DNA to research the population. genetics of P. guimbeaui in response to habitat fragmentation. Finally, I explored habitat selection of P. guimbeaui to find suita~le sites for potential translocations. First, I showed that P. grandis shared many characteristics of an invasive species and could persist in a relatively large range of environmental conditions. The results highlight that P. grandis and endemic gecko distributions can overlap. Where P .. grandis has invaded areas occupied by endemic geckos, the abundance of the Mauritian species has declined by an average of 89%. This study provides strong evidence that P. grandis and endemic geckos are unlikely to coexist in sympatry. Second, I designed arid amplified 44 markers from an enriched-microsatellite genomic library. They were tested on ten subpopulations and 20 were selected to examine the population genetics of the fragmented population of P. guimbeaui. Here, the microsatellite results suggested that most subpopulations were genetically different, with low effective population sizes and no migrations, while simulations showed that the different subpopulations were at high risks of losing genetic diversity and extinction. Mitochondrial DNA showed that the fragmented subpopulations used to be part of a panmictic population. Using the findings of this genetic study, 12 subpopulations were identified as viable and 18 subpopulations were at high risk. Third, I showed that P. guimbeaui males had a larger home range than females and males overlap more with females than males and geckos selected habitats with higher plant diversity, with trees that had taller and larger trunks and a higher cavity density. Adult geckos selected different habitat features compared to sub-adults and juveniles. The findings of this research were synthesised into a review to formulate the conservation assessment of the endemic geckos on mainland Mauritius.