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Silica aerogel for capturing intact interplanetary dust particles for the Tanpopo experiment  [PDF]
Makoto Tabata,Hajime Yano,Hideyuki Kawai,Eiichi Imai,Yuko Kawaguchi,Hirofumi Hashimoto,Akihiko Yamagishi
Physics , 2015, DOI: 10.1007/s11084-015-9423-8
Abstract: In this paper, we report the progress in developing a silica-aerogel-based cosmic dust capture panel for use in the Tanpopo experiment on the International Space Station (ISS). Previous studies revealed that ultralow-density silica aerogel tiles comprising two layers with densities of 0.01 and 0.03 g/cm$^3$ developed using our production technique were suitable for achieving the scientific objectives of the astrobiological mission. A special density configuration (i.e., box framing) aerogel with a holder was designed to construct the capture panels. Qualification tests for an engineering model of the capture panel as an instrument aboard the ISS were successful. Sixty box-framing aerogel tiles were manufactured in a contamination-controlled environment.
Arm-in-cage testing of natural human-derived mosquito repellents
James G Logan, Nina M Stanczyk, Ahmed Hassanali, Joshua Kemei, Ant?nio EG Santana, Karlos AL Ribeiro, John A Pickett, A Jennifer Mordue (Luntz)
Malaria Journal , 2010, DOI: 10.1186/1475-2875-9-239
Abstract: To test whether these chemicals could provide protection against mosquitoes, laboratory repellency trials were carried out to test the chemicals individually at different concentrations and in different mixtures and ratios with three major disease vectors: Anopheles gambiae, Culex quinquefasciatus and Aedes aegypti.Up to 100% repellency was achieved depending on the type of repellent compound tested, the concentration and the relative composition of the mixture. The greatest effect was observed by mixing together two compounds, 6-methyl-5-hepten-2-one and geranylacetone in a 1:1 ratio. This mixture exceeded the repellency of DEET when presented at low concentrations. The repellent effect of this mixture was maintained over several hours. Altering the ratio of these compounds significantly affected the behavioural response of the mosquitoes, providing evidence for the ability of mosquitoes to detect and respond to specific mixtures and ratios of natural repellent compounds that are associated with host location.The optimum mixture of 6-methyl-5-hepten-2-one and geranylacetone was a 1:1 ratio and this provided the most effective protection against all species of mosquito tested. With further improvements in formulation, selected blends of these compounds have the potential to be exploited and developed as human-derived novel repellents for personal protection.Repellents play an important role in disrupting the interaction between mosquitoes and human beings by reducing bites [1]. Mosquito repellents are mainly accessible to people in developed countries for nuisance insects and to travellers. One of the most widely used and effective insect repellents available is the synthetic compound, N,N-diethyl-m-toluamide (DEET) and this compound is generally considered to be the "gold standard" repellent, providing long-lasting protection of up to 8 h from time of application [2]. However, there are some rare reports of severe reactions in people, additionally DEET melts plasti
Field Cage Studies and Progressive Evaluation of Genetically-Engineered Mosquitoes  [PDF]
Luca Facchinelli ,Laura Valerio,Janine M. Ramsey,Fred Gould,Rachael K. Walsh,Guillermo Bond,Michael A. Robert,Alun L. Lloyd,Anthony A. James,Luke Alphey,Thomas W. Scott
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002001
Abstract: Background A genetically-engineered strain of the dengue mosquito vector Aedes aegypti, designated OX3604C, was evaluated in large outdoor cage trials for its potential to improve dengue prevention efforts by inducing population suppression. OX3604C is engineered with a repressible genetic construct that causes a female-specific flightless phenotype. Wild-type females that mate with homozygous OX3604C males will not produce reproductive female offspring. Weekly introductions of OX3604C males eliminated all three targeted Ae. aegypti populations after 10–20 weeks in a previous laboratory cage experiment. As part of the phased, progressive evaluation of this technology, we carried out an assessment in large outdoor field enclosures in dengue endemic southern Mexico. Methodology/Principal Findings OX3604C males were introduced weekly into field cages containing stable target populations, initially at 10:1 ratios. Statistically significant target population decreases were detected in 4 of 5 treatment cages after 17 weeks, but none of the treatment populations were eliminated. Mating competitiveness experiments, carried out to explore the discrepancy between lab and field cage results revealed a maximum mating disadvantage of up 59.1% for OX3604C males, which accounted for a significant part of the 97% fitness cost predicted by a mathematical model to be necessary to produce the field cage results. Conclusions/Significance Our results indicate that OX3604C may not be effective in large-scale releases. A strain with the same transgene that is not encumbered by a large mating disadvantage, however, could have improved prospects for dengue prevention. Insights from large outdoor cage experiments may provide an important part of the progressive, stepwise evaluation of genetically-engineered mosquitoes.
Calibration and evaluation of field cage for oviposition study with Aedes (Stegomyia) aegypti female (L.) (Diptera: Culicidae)
Roque, Rosemary A.;Eiras, álvaro E.;
Neotropical Entomology , 2008, DOI: 10.1590/S1519-566X2008000400018
Abstract: differences among results gathered from insect behavior studies conducted in laboratory and field situations are due to ambient variables that differ greatly between both environments. in laboratory studies the environmental conditions can be controlled whereas in field temperature, humidity and air velocity vary uncontrollably. the objective of this study was to calibrate and evaluate an experimental area (field cage) (14 x 7 x 3.5 m) subdivided into eight test cages (2.5 x 2.5 x 2 m) for use in behavioral oviposition tests of aedes aegypti (l.) mosquitoes for developing a new methodology to assess attractants and oviposition traps. test cage calibration involved: (1) minimal experiment duration tests; (2) optimal female release number per traps test and (3) trap placement tests. all tests used gravid a. aegypti females; 3-4 days post blood meal and the sticky trap mosquitrap? to catch adults. ninety percent of the females released were recaptured 2h after the beginning of the experiment, and this allowed up to 32 test repetitions/day to be conducted in the field cage. the minimum number of females necessary to conduct statistical analyses was 20 females/trap/test per cage. no significant difference was found in the behavioral response of gravid females to four different trap positions within test cages. field trapping results with attractant were similar to those in the field cage. therefore, the field cage could replace field trapping for evaluating at least mosquito traps and oviposition attractants for a. aegypti.
Cage diffusion in liquid mercury  [PDF]
Y. S. Badyal,U. Bafile,K. Miyazaki,I. M. de Schepper,W. Montfrooij
Physics , 2003, DOI: 10.1103/PhysRevE.68.061208
Abstract: We present inelastic neutron scattering measurements on liquid mercury at room temperature for wave numbers $q$ in the range 0.3 $< q <$ 7.0 \AA$^{-1}$. We find that the energy halfwidth of the incoherent part of the dynamic structure factor $S(q,E)$ is determinded by a self-diffusion process. The halfwidth of the coherent part of $S(q, E)$ shows the characteristic behavior expected for a cage diffusion process. We also show that the response function at small wave numbers exhibits a quasi-elastic mode with a time scale characteristic of cage diffusion, however, its intensity is larger by an order of magnitude than what would be expected for cage diffusion. We speculate on a scenario in which the intensity of the cage diffusion mode at small wave numbers is amplified through a valence fluctuation mechanism.
Mosquito traps designed to capture Aedes aegypti (Diptera: Culicidae) females: preliminary comparison of Adultrap, MosquiTRAP and backpack aspirator efficiency in a dengue-endemic area of Brazil
Maciel-de-Freitas, Rafael;Peres, Roberto Costa;Alves, Fernando;Brandolini, Mauro Blanco;
Memórias do Instituto Oswaldo Cruz , 2008, DOI: 10.1590/S0074-02762008000600016
Abstract: in this report, the efficiency of adultrap under field conditions is compared to a cdc backpack aspirator and to mosquitrap. an urban dengue-endemic area of rio de janeiro was selected to evaluate the efficiency of mosquito traps in capturing aedes aegypti females. adultrap and aspirator captured similar numbers of ae. aegypti females, with the former showing high specificity to gravid individuals (93.6%). a subsequent mark-release-recapture experiment was conducted to evaluate adultrap and mosquitrap efficiency concomitantly. with a 6.34% recapture rate, mosquitrap captured a higher mean number of female ae. aegypti per trap than adultrap (?2 = 14.26; df = 1; p < 0,05). however, some mosquitraps (28.12%) contained immature ae. aegypti after 18 days of exposure in the field and could be pointed as an oviposition site for female mosquitoes. both trapping methods, designed to collect gravid ae. aegypti females, seem to be efficient, reliable and may aid routine ae. aegypti surveillance.
Mobile Phone Faraday Cage  [PDF]
M M J French
Physics , 2011, DOI: 10.1088/0031-9120/46/3/005
Abstract: A Faraday cage is an interesting physics phenomena where an electromagnetic wave can be excluded from a volume of space by enclosure with an electrically conducting material. The practical application of this in the classroom is to block the signal to a mobile phone by enclosing it in a metal can! The background of the physics behind this is described in some detail followed by a explanation of some demonstrations and experiments which I have used.
Capturing Hiproofs in HOL Light  [PDF]
Steven Obua,Mark Adams,David Aspinall
Computer Science , 2013,
Abstract: Hierarchical proof trees (hiproofs for short) add structure to ordinary proof trees, by allowing portions of trees to be hierarchically nested. The additional structure can be used to abstract away from details, or to label particular portions to explain their purpose. In this paper we present two complementary methods for capturing hiproofs in HOL Light, along with a tool to produce web-based visualisations. The first method uses tactic recording, by modifying tactics to record their arguments and construct a hierarchical tree; this allows a tactic proof script to be modified. The second method uses proof recording, which extends the HOL Light kernel to record hierachical proof trees alongside theorems. This method is less invasive, but requires care to manage the size of the recorded objects. We have implemented both methods, resulting in two systems: Tactician and HipCam.
Prevention of mosquito borne diseases by using mosquito repellents  [cached]
Saurabh Dahiya,Prof.Roop K.Khar,Dr. Aruna Chhikkara
Pharmaceutical Reviews , 2006,
Abstract: Mosquitoes, the disease transmitters are responsible for around 1.3 milliondeaths annually. Diseases such as West Nile Virus, malaria, dengue fever andyellow fever are transmitted to humans by blood-feeding mosquitoes.The immediate hypersensitivity and delayed hypersensitivity reactions aredue to mosquito bites. Chemical remedies for mosquito bites are applicationof antihistamines, diphenhydramine and topical corticosteroids. An understandingof vector’s lifecycle and behavioural characteristics guides mosquito controlactivities. Meta-N, N diethyl toluamide (DEET) protects against tick bitesand mosquito bites by blocking insect receptors which are used to locate hosts.DEET products are safest and most effective insect repellents. Naturally occurringrepellants are usually plant volatile oils like pyrethrum. Permethrinis a synthetic pyrethroid causing nervous system toxicity of the insect leadingto its death. The repellant activities can be measured by the blood-feedingmembrane tests. Safe and effective repellants should be chosen.
Density of Range Capturing Hypergraphs  [PDF]
Maria Axenovich,Torsten Ueckerdt
Computer Science , 2014,
Abstract: For a finite set $X$ of points in the plane, a set $S$ in the plane, and a positive integer $k$, we say that a $k$-element subset $Y$ of $X$ is captured by $S$ if there is a homothetic copy $S'$ of $S$ such that $X\cap S' = Y$, i.e., $S'$ contains exactly $k$ elements from $X$. A $k$-uniform $S$-capturing hypergraph $H = H(X,S,k)$ has a vertex set $X$ and a hyperedge set consisting of all $k$-element subsets of $X$ captured by $S$. In case when $k=2$ and $S$ is convex these graphs are planar graphs, known as convex distance function Delaunay graphs. In this paper we prove that for any $k\geq 2$, any $X$, and any convex compact set $S$, the number of hyperedges in $H(X,S,k)$ is at most $(2k-1)|X| - k^2 + 1 - \sum_{i=1}^{k-1}a_i$, where $a_i$ is the number of $i$-element subsets of $X$ that can be separated from the rest of $X$ with a straight line. In particular, this bound is independent of $S$ and indeed the bound is tight for all "round" sets $S$ and point sets $X$ in general position with respect to $S$. This refines a general result of Buzaglo, Pinchasi and Rote stating that every pseudodisc topological hypergraph with vertex set $X$ has $O(k^2|X|)$ hyperedges of size $k$ or less.
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