228 research outputs found
Distribution, Food and Life History of Tiger Salamanders in Devils Lake, North Dakota
Food, growth, distribution, migration, metamorphosis, neoteny, and breeding habits of Ambystoma tigrinum diaboli Dunn were studied in Devils Lake, North Dakota. Salamanders I vere captured in gill and frame nets, and growth and metamorphosis were followed on specimens caged in the lake, lood habits were ascertained from stomach analyses and migrating adults were caught in gill nets and trench-barrier t raps.
Salamander adults breed readily in Devils Lake and display a sex ratio of 13 females to 10 males. The population appears to consist of larvae, neotenous gilled forms, aid adults. Adults leave the lake in fall and return in spring; larvae are present from time of egg hatching until late summer when they change to adults or neotenies t neotenous forms are apparently present at all seasons unless eradicated by winter kill. Breeding by neotenous forms was neither verified nor refuted; females had eggs in the body cavity in the fall of 1967 and had lost them before ice\u27melt in 1968. Major growth occurs during the first summer after hatching, but neotenies continued growth at a much slower rate during the second summer. Both larvae and neotenios metamorphosed into adults. Metamorphosis of neotenies could be induced by penning them in the lake or removing them to tanks and aquaria. Amphipods were the major food item of all 3 categories. Gastric and intestinal nematodes and cestodes were the only parasites found
Brief communication: Comparison of the performance of thermistors and digital temperature sensors in a mountain permafrost borehole
Monitoring mountain-permafrost temperatures in boreholes is challenging
regarding the resilience and long-term temperature stability of the sensor
systems. Whilst resistance thermistors boast a high accuracy, they are prone
to drift when exposed to moisture, pressure or cable strain. Supplementing
or replacing them with digital bandgap temperature sensors requires careful
analysis of the sensor performance. We carry out a first comparison of two
temperature sensor systems under field conditions in mountain permafrost at
15 identical depths in 1 borehole. Temperature values, sensing delays and
noise levels are compared and discussed.</p
Engineering Entrainment and Adaptation in Limit Cycle Systems -- From biological inspiration to applications in robotics
Adaptive Frequency Oscillators applied to dynamic walking II. Adapting to resonant body dynamics
Identification of Class I HLA T Cell Control Epitopes for West Nile Virus
The recent West Nile virus (WNV) outbreak in the United States underscores the importance of understanding human immune responses to this pathogen. Via the presentation of viral peptide ligands at the cell surface, class I HLA mediate the T cell recognition and killing of WNV infected cells. At this time, there are two key unknowns in regards to understanding protective T cell immunity: 1) the number of viral ligands presented by the HLA of infected cells, and 2) the distribution of T cell responses to these available HLA/viral complexes. Here, comparative mass spectroscopy was applied to determine the number of WNV peptides presented by the HLA-A*11:01 of infected cells after which T cell responses to these HLA/WNV complexes were assessed. Six viral peptides derived from capsid, NS3, NS4b, and NS5 were presented. When T cells from infected individuals were tested for reactivity to these six viral ligands, polyfunctional T cells were focused on the GTL9 WNV capsid peptide, ligands from NS3, NS4b, and NS5 were less immunogenic, and two ligands were largely inert, demonstrating that class I HLA reduce the WNV polyprotein to a handful of immune targets and that polyfunctional T cells recognize infections by zeroing in on particular HLA/WNV epitopes. Such dominant HLA/peptide epitopes are poised to drive the development of WNV vaccines that elicit protective T cells as well as providing key antigens for immunoassays that establish correlates of viral immunity. © 2013 Kaabinejadian et al
Quantitative In Vivo Magnetic Resonance Spectroscopy Using Synthetic Signal Injection
Accurate conversion of magnetic resonance spectra to quantitative units of concentration generally requires compensation for differences in coil loading conditions, the gains of the various receiver amplifiers, and rescaling that occurs during post-processing manipulations. This can be efficiently achieved by injecting a precalibrated, artificial reference signal, or pseudo-signal into the data. We have previously demonstrated, using in vitro measurements, that robust pseudo-signal injection can be accomplished using a second coil, called the injector coil, properly designed and oriented so that it couples inductively with the receive coil used to acquire the data. In this work, we acquired nonlocalized phosphorous magnetic resonance spectroscopy measurements from resting human tibialis anterior muscles and used pseudo-signal injection to calculate the Pi, PCr, and ATP concentrations. We compared these results to parallel estimates of concentrations obtained using the more established phantom replacement method. Our results demonstrate that pseudo-signal injection using inductive coupling provides a robust calibration factor that is immune to coil loading conditions and suitable for use in human measurements. Having benefits in terms of ease of use and quantitative accuracy, this method is feasible for clinical use. The protocol we describe could be readily translated for use in patients with mitochondrial disease, where sensitive assessment of metabolite content could improve diagnosis and treatment
Postcolonial manifestations of African spatiality in Europe : the invisible 'public' spaces of Ghent
The focus of this chapter is on everyday spaces of African migration in the mid-sized city of Ghent. One manifestation of African spatiality is discussed in-depth in relation to its (in)visibility and publicity: an African shop located in an ordinary terraced house. With no less than 12 activities taking place in the building, the shop is rather a âpublicâ place than solely a space of commercial transactions, although this is not signaled in very visible ways. By analyzing the modest stylistic appropriations of the façade and the significant re-arrangements of the buildingsâ interior spaces that challenge more conventional usages of spaces in Ghentâs ordinary houses, this chapter puts this African shop to the fore as emblematic of how the process of materialization of transnational lifestyles and connections is always a balancing act between the visibility necessary for functioning as a (semi-)pubic place and the invisibility required to circumvent hegemonic regulatory regimes
Creative Reverse Engineering â from remote sensuality to haptic metrology
Our ongoing experimentation in close-range Photogrammetry has overcome common challenges to generate accurate, high-resolution 3D models using a single DSLR camera and innovative approaches and computer-coded devices. More recent investigations across disciplines sought to bridge the gap between traditional creative skills and modes of visualisation, and what can be made possible through digital means. Working as artists and designers alongside museums and historians, we have developed new photogrammetry equipment and approaches to help overcome the complex fluid geometry, shadowy occlusions and delicate lamina edges of challenging monochromatic garments. The resulting 3D models have allowed the rapid extraction of faithful seams and surfaces direct from the processed âmeshâ and into CAD modelling environments for the production of new designs, patterns and production tooling. Current collaborations seek to apply these developments to the capture, visualisation and reverse engineering of iconic garments and museum artefacts, alongside the 'remote sensing' of traditional pattern cutters whose eyes, minds and hands are the equivalent of the digital approaches explored in our paper.
The second phase sought to unpick some of the familiar structures of object- and asset creation in and for Virtual and Augmented Reality. Experimenting with equipment, methods and processing techniques allowed us to explore the potential of 3D visualisations and readily available tools within Virtual and Augmented Reality for garment design and other forms of object-based creative ideation, sketching and prototyping. In the next stages of our ongoing research we explored a more haptic form of CAD-enabled modelling and metrology, aiming to bring these approaches within the reach of a wider range of creative users: enabling artists, designers and makers to move more seamlessly between digital tools and virtual environments, and actual things in real time and space
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