2,248 research outputs found
Effect of excited states and applied magnetic fields on the measured hole mobility in an organic semiconductor
Copyright 2010 by the American Physical Society. Article is available at
#15 - Assessing the presence of Wolbachia in the mosquito populations of Northeast Georgia, USA
Wolbachia, a Gram-negative bacterium that infects mosquitoes along with other arthropods, can suppress the spread of microfilaria through reducing the populations of mosquitoes that carry the heartworms. Historically, research has been conducted to use in the prevention of infections from parasites or viruses like Zika or yellow fever. It is important to understand ways of preventing the various infections from occurring not only by host prevention but through vector prevention or suppression. In the summer of 2018, a total of thirty-five adult female mosquitoes were collected in Oakwood, Georgia at the University of North Georgia in two locations between May 29, 2018 through August 10, 2018 to evaluate for microfilaria and Wolbachia. Following evaluation for microfilaria, DNA extraction from each mosquito was completed for polymerase chain reaction (PCR) testing to test for Wolbachia presence and absence. Data analysis is being continued at this time. Determining the presence of Wolbachia in our adult female samples could help us better determine ways to control mosquito populations to slow or halt the spread of ultimately fatal diseases, parasites, and viruses that are transmitted through adult female mosquitoes. Research conducted through PCR could lead to larger scale research projects sampling mosquitoes for this high-impact bacterium in the future
Intravascular coagulation resulting from intravenous injection of C. parvum in mice.
In mice, i.v. C. parvum induces intravascular coagulation. This is a prolonged reaction lasting up to 7 days. It results in thrombosis in hepatic vessels with consequent hepatic necrosis, and thrombosis in pulmonary and splenic vessels. This may be important in the assessment of the tumour-inhibitory activity of C. parvum
Bias-Dependent Generation and Quenching of Defects in Pentacene
We describe a defect in pentacene single crystals that is created by bias
stress and persists at room temperature for an hour in the dark but only
seconds with 420nm illumination. The defect gives rise to a hole trap at Ev +
0.38eV and causes metastable transport effects at room temperature. Creation
and decay rates of the hole trap have a 0.67eV activation energy with a small
(108 s-1) prefactor, suggesting that atomic motion plays a key role in the
generation and quenching process.Comment: 10 pages, 3 figure
Circle talks as situated experiential learning: Context, identity, and knowledgeability in \u27learning from reflection\u27
This article presents research that used ethnographic and sociolinguistic methods to study ways participants learn through reflection when carried out as a “circle talk.” The data indicate that participants in the event (a) invoked different contextual frames that (b) implicated them in various identity positions, which (c) affected how they could express their knowledge. These features worked together to generate socially shared meanings that enabled participants to jointly achieve conceptualization—the ideational role “reflection” is presumed to play in the experiential learning process. The analysis supports the claim that participants generate new knowledge in reflection, but challenges individualistic and cognitive assumptions regarding how this occurs. The article builds on situated views of experiential learning by showing how knowledge can be understood as socially shared and how learning and identity formation are mutually entailing processes
Study of molecular spin-crossover complex Fe(phen)2(NCS)2 thin films
We report on the growth by evaporation under high vacuum of high-quality thin
films of Fe(phen)2(NCS)2 (phen=1,10-phenanthroline) that maintain the expected
electronic structure down to a thickness of 10 nm and that exhibit a
temperature-driven spin transition. We have investigated the current-voltage
characteristics of a device based on such films. From the space charge-limited
current regime, we deduce a mobility of 6.5x10-6 cm2/V?s that is similar to the
low-range mobility measured on the widely studied
tris(8-hydroxyquinoline)aluminium organic semiconductor. This work paves the
way for multifunctional molecular devices based on spin-crossover complexes
Automictic Reproduction in Interspecific Hybrids of Poeciliid Fish
SummaryAutomixis, the process whereby the fusion of meiotic products restores the diploid state of the egg, is a common mode of reproduction in plants but has also been described in invertebrate animals [1, 2]. In vertebrates, however, automixis has so far only been discussed as one of several explanations for isolated cases of facultative parthenogenesis [3, 4]. Analyzing oocyte formation in F1 hybrids derived from Poecilia mexicana limantouri and P. latipinna crosses (the cross that led to the formation of the gynogenetic Poecilia formosa[5, 6]), we found molecular evidence for automictic oocyte production [7]. The mechanism involves the random fusion of meiotic products after the second meiotic division. The fertilization of diploid oocytes gives rise to fully viable triploid offspring. Although the automictic production of diploid oocytes as seen in these F1 hybrids clearly represents a preadaptation to parthenogenetic reproduction [8], it is also a powerful intrinsic postzygotic isolation mechanism because the resulting next generation triploids were always sterile. The mechanism described here can explain facultative parthenogenesis [9], as well as varying ploidy levels reported in different animal groups [10]. Most importantly, at least some of the reported cases of triploidy in humans [11] can now be traced back to automixis
Production Mechanism for Quark Gluon Plasma in Heavy Ion Collisions
A general scheme is proposed here to describe the production of semi soft and
soft quarks and gluons that form the bulk of the plasma in ultra relativistic
heavy ion collisions. We show how to obtain rates as a function of time in a
self consistent manner, without any ad-hoc assumption. All the required
features - the dynamical nature of QCD vacuum, the non-Markovian nature of the
production, and quasi particle nature of the partons, and the importance of
quantum interference effects are naturally incorporated. We illustrate the
results with a realistic albeit toy model and show how almost all the currently
employed source terms are unreliable in their predictions. We show the rates in
the momentum space and indicate at the end how to extract the full phase-space
dependence.Comment: 4 pages, 4 figures, two colum
Charge injection instability in perfect insulators
We show that in a macroscopic perfect insulator, charge injection at a
field-enhancing defect is associated with an instability of the insulating
state or with bistability of the insulating and the charged state. The effect
of a nonlinear carrier mobility is emphasized. The formation of the charged
state is governed by two different processes with clearly separated time
scales. First, due to a fast growth of a charge-injection mode, a localized
charge cloud forms near the injecting defect (or contact). Charge injection
stops when the field enhancement is screened below criticality. Secondly, the
charge slowly redistributes in the bulk. The linear instability mechanism and
the final charged steady state are discussed for a simple model and for
cylindrical and spherical geometries. The theory explains an experimentally
observed increase of the critical electric field with decreasing size of the
injecting contact. Numerical results are presented for dc and ac biased
insulators.Comment: Revtex, 7pages, 4 ps figure
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