Reaction Time of a Group of Physics Students

The reaction time of a group of students majoring in Physics is reported here. Strong co-relation between fatigue, reaction time and performance have been seen and may be useful for academicians and administrators responsible of working out time-tables, course structures, students counsellings etc.Comment: 10 pages, 4 figure

Tubular structures of GaS

In this Brief Report we demonstrate, using density-functional tight-binding theory, that gallium sulfide (GaS) tubular nanostructures are stable and energetically viable. The GaS-based nanotubes have a semiconducting direct gap which grows towards the value of two-dimensional hexagonal GaS sheet and is in contrast to carbon nanotubes largely independent of chirality. We further report on the mechanical properties of the GaS-based nanotubes

An Introduction to Xeroradiography

The history and physical principles of xeroradiography are given. The advantages and applications of the technique are enumerated and a 'working' description of the essential components of the Xerox system included. Mammograms of exceptionally high quality have been produced with no difficulty, and with few problems. The unit has proved reliable

The calculation of the spanwise loading of sweptback wings with flaps or all-moving tips at subsonic speeds

The results of some electric tank tests by Duquenne and Grandjean on wings of 45 deg sweepback with trailing edge flaps have been analysed to provide the basis for a method of calculating the spanwise loading. The analysis yielded information about the effect of sweep on the equivalent incidence of a section with flap, on the downwash factor and on the spanwise loading distribution with an incidence discontinuity. Interpolation formulae are developed to extend the results to wings of any sweep and flap span, and thus a complete calculation method is presented for the spanwise loading with this type of control. The calculation method is tentatively extended to a wing with all-moving tip control, and the results compared with those of Thomas and Mangler. There is a marked discrepancy between the two calculations. Further electric tank tests to fill this, and other gaps are suggested

Swelling of a Cell Lumen Filled and A Cell-Wall Bulked Wood Polymer Composite in Water

Liquid water swelling of lumen-filled and cell-wall bulked wood polymer composite (WPC) samples was measured at room temperature and 80 C. Ultimate swelling was greater (approximately that of untreated wood) and moisture diffusion coefficient lower for the lumen filled wood. The higher density, lumen filled sample had lower swelling than the lower density one. At 80 C, fiber saturation points (FSP) were 8% for the cell-wall samples and above 20% for the cell lumen samples. The FSP for more highly loaded cell lumen samples was lower than that for lower loading

A generalized equation for the calculation of receptor noise limited colour distances in n-chromatic visual systems

Researchers must assess similarities and differences in colour from an animal's eye view when investigating hypotheses in ecology, evolution and behaviour. Nervous systems generate colour perceptions by comparing the responses of different spectral classes of photoreceptor through colour opponent mechanisms, and the performance of these mechanisms is limited by photoreceptor noise. Accordingly, the receptor noise limited (RNL) colour distance model of Vorobyev and Osorio (Vorobyev & Osorio 1998 Proc. R. Soc. Lond. B 265, 351?358 (doi:10.1098/rspb.1998.0302)) generates predictions about the discriminability of colours that agree with behavioural data, and consequently it has found wide application in studies of animal colour vision. Vorobyev and Osorio (1998) provide equations to calculate RNL colour distances for animals with di-, tri- and tetrachromatic vision, which is adequate for many species. However, researchers may sometimes wish to compute RNL colour distances for potentially more complex colour visual systems. Thus, we derive a simple, single formula for the computation of RNL distance between two measurements of colour, equivalent to the published di-, tri- and tetrachromatic equations of Vorobyev and Osorio (1998), and valid for colour visual systems with any number of types of noisy photoreceptors. This formula will allow the easy application of this important colour visual model across the fields of ecology, evolution and behaviour.publishersversionPeer reviewe

Formation and bleaching of strong ultraviolet absorption bands in germanium implanted synthetic fused silica

Germanium ions have been implanted in fused silica using ion beams having energies of 3 and 5 MeV and doses ranging from 1×1012 to 5×1014 ions/cm2. For wavelengths shorter than 400 nm, the optical absorption increases strongly with two absorption bands appearing at 244 and 212 nm. The ion-induced optical absorption can be bleached almost completely by irradiation with 249 nm excimer laser light. Ion implantation also increases the refractive index of silica near the substrate surface. At 632.8 nm a refractive index increase of more than 10-2 has been measured. This decreases by 4×10-3 upon bleaching with 249 nm light

Ratting on wildlife crime : training African giant pouched rats to detect illegally trafficked wildlife

DATA AVAILABITY STATEMENT: APOPO will not make the detailed list of non-target materials readily available due to the sensitivity of details on specific masking materials rats have been trained on. This is to ensure every precaution is taken to not share this information with trafficking networks. A randomized version of the data can be made available on request. Requests to access the datasets should be directed to www.apopo.orgThe illegal wildlife trade (IWT) is one of the largest global crime economies, directly threatening species and their habitats, and biodiversity, and indirectly the global climate, and countries’ economies. Syndicates operating within the IWT are often involved in trafficking of humans, weapons, and drugs. IWT takes place in large scale through international ports, with wildlife being smuggled inside shipping containers. Current methods to combat IWT and screen these shipping containers, such as X-ray scans, are expensive and time-consuming. Scent detection animals present an innovative approach to combatting IWT, as animals may be better suited to distinguish between organic materials and less susceptible to visual concealment methods. Previous scent-detection work has largely focused on conservation dogs (Canis lupus familiaris). Here, we present a series of proof-of-principle studies training African giant pouched rats (Cricetomys ansorgei) to detect illegally trafficked wildlife. As initial proof-of principle within a controlled laboratory environment, we trained rats (n=11) to detect the scent of pangolin scales (Manis spp.) and a threatened African hardwood (Dalbergia melanoxylon). In subsequent experiments, we trained these rats (n=10) to detect rhinoceros horn (family Rhinocerotidae), and elephant tusks (Loxodonta spp.). At the conclusion of these studies, rats (n=7) accurately identified all four target species (although ivory samples may have been cross-contaminated, and results should be interpreted with caution) while correctly rejecting non-target items commonly used by traffickers to conceal the presence of illicit material. Rats detected the presence of wildlife targets even when these were concealed in mixtures among non-target items. These results provide the foundation to train rats for scent-detection of illegally trafficked wildlife to combat IWT. The unique attributes of rats could allow them to complement existing screening technologies in the fight against IWT. Rats have low training and maintenance costs, flexibly work with multiple handlers, have a long lifespan, and a sophisticated sense of smell. Their small size also offers unique capabilities for the screening of shipping containers, such as being able to navigate densely packed areas or be lifted to assess contents of sealed containers by screening ventilation systems. Future directions include assessing operational feasibility of deploying rats at ports.The U.S. Fish and Wildlife Services (USFWS), the Illegal Wildlife Trade Challenge Fund of the United Kingdom (UK), US AID, the “Partnership against Poaching and Illegal Wildlife Trade”, implemented by GIZ on behalf of the German Federal Ministry for Economic Cooperation and Development (BMZ) and the German Federal Ministry for Environment, Nature Conservation and Nuclear Safety (BMU), as well as the World Conservation Network’s Pangolin Crisis Fund.https://www.frontiersin.org/journals/conservation-scienceZoology and EntomologySDG-15:Life on landSDG-16:Peace,justice and strong institution