363 research outputs found

    Evaluation of Aedes aegypti densonucleosis (AeDNV) infection in adult mosquito mortality

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    Aedes aegypti densonucleosis virus (AeDNV) has long been considered a likely agent in biologic control against arthropod-borne diseases. Extensive studies have been done to evaluate infection and pathogeneses in Aedes aegypti larvae and pupae, but only primary studies have been preformed in adults. The primary studies on adult mortality produced a two part mortality curve that showed high levels of early mortality, low levels of intermediate mortality and high levels of late mortality. It was hypothesized that the high levels of early mortality were due to high levels of virus infection, whereas the high levels late mortality were due to old age. In this study we analyzed the mosquitoes that died early and late in the mortality assay with quantitative PCR to determine virus titers in individual mosquitoes. We found that there is no significant difference between titer level of mosquitoes that died in the early part of the curve (Day 17-29), which had an average of 1.264 x 1011 genome equivalents per ml and those that died in the late part of the curve (Day 45-54), which had an average of 2.255 x 1011 genome equivalents per ml.Highest Honors

    Paraneoplastic and Other Autoimmune Encephalitides: Antineuronal Antibodies, T Lymphocytes, and Questions of Pathogenesis

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    Autoimmune and paraneoplastic encephalitides represent an increasingly recognized cause of devastating human illness as well as an emerging area of neurological injury associated with immune checkpoint inhibitors. Two groups of antibodies have been detected in affected patients. Antibodies in the first group are directed against neuronal cell surface membrane proteins and are exemplified by antibodies directed against the N-methyl-D-aspartate receptor (anti-NMDAR), found in patients with autoimmune encephalitis, and antibodies directed against the leucine-rich glioma-inactivated 1 protein (anti-LGI1), associated with faciobrachial dystonic seizures and limbic encephalitis. Antibodies in this group produce non-lethal neuronal dysfunction, and their associated conditions often respond to treatment. Antibodies in the second group, as exemplified by anti-Yo antibody, found in patients with rapidly progressive cerebellar syndrome, and anti-Hu antibody, associated with encephalomyelitis, react with intracellular neuronal antigens. These antibodies are characteristically found in patients with underlying malignancy, and neurological impairment is the result of neuronal death. Within the last few years, major advances have been made in understanding the pathogenesis of neurological disorders associated with antibodies against neuronal cell surface antigens. In contrast, the events that lead to neuronal death in conditions associated with antibodies directed against intracellular antigens, such as anti-Yo and anti-Hu, remain poorly understood, and the respective roles of antibodies and T lymphocytes in causing neuronal injury have not been defined in an animal model. In this review, we discuss current knowledge of these two groups of antibodies in terms of their discovery, how they arise, the interaction of both types of antibodies with their molecular targets, and the attempts that have been made to reproduce human neuronal injury in tissue culture models and experimental animals. We then discuss the emerging area of autoimmune neuronal injury associated with immune checkpoint inhibitors and the implications of current research for the treatment of affected patients.publishedVersio

    Geophysical constraints on mirror matter within the Earth

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    We have performed a detailed investigation of geophysical constraints on the possible admixture of mirror matter inside the Earth. On the basis of the Preliminary Reference Earth Model (PREM) -- the `Standard Model' of the Earth's interior -- we have developed a method which allows one to compute changes in various quantities characterising the Earth (mass, moment of inertia, normal mode frequencies etc.)due to the presence of mirror matter. As a result we have been able to obtain for the first time the direct upper bounds on the possible concentration of the mirror matter in the Earth. In terms of the ratio of the mirror mass to the Earth mass a conservative upper bound is 3.8×1033.8\times 10^{-3}. We then analysed possible mechanisms (such as lunar and solar tidal forces, meteorite impacts and earthquakes) of exciting mirror matter oscillations around the Earth centre. Such oscillations could manifest themselves through global variations of the gravitational acceleration at the Earth's surface. We conclude that such variations are too small to be observed. Our results are valid for other types of hypothetical matter coupled to ordinary matter by gravitation only (e.g. the shadow matter of superstring theories).Comment: 25 pages, in RevTeX, to appear in Phys.Rev.

    Parametric resonance of neutrino oscillations and passage of solar and atmospheric neutrinos through the earth

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    We present an exact analytic solution to the neutrino evolution equation in matter with periodic step-function density profile and discuss in detail the parametric resonance of neutrino oscillations that can occur in such a system. Solar and atmospheric neutrinos traversing the earth pass through layers of alternating density and can therefore experience parametric resonance of their oscillations. Atmospheric neutrinos can undergo parametrically enhanced oscillations in the earth when their trajectories deviate from the vertical by about 263226^\circ - 32^\circ. Solar neutrinos traversing the earth can experience a strong parametric resonance of their oscillations in a wide range of zenith angles. If the small mixing angle MSW effect is the solution of the solar neutrino problem, the oscillations of solar neutrinos crossing the core of the earth {\em must} undergo strong parametric resonance; this phenomenon should facilitate significantly the observation of the day-night effect in oscillations of solar neutrinos. If observed, the enhanced day-night effect for core crossing neutrinos would therefore confirm both the MSW solution of the solar neutrino problem and the parametric resonance of neutrino oscillations.Comment: LaTeX, 38 pages, 12 figures, requires epsfig. References added, a typo in figure captions corrected, 4 figures removed. Version to be published in Nucl. Phys.

    Facial Scars: Do Position and Orientation Matter?

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    Background: This study tested the core tenets of how facial scars are perceived by characterizing layperson response to faces with scars. The authors predicted that scars closer to highly viewed structures of the face (i.e., upper lip and lower lid), scars aligned against resting facial tension lines, and scars in the middle of anatomical subunits of the face would be rated less favorably. Methods: Volunteers aged 18 years and older from the United States were recruited through Amazon’s Mechanical Turk to complete a face rating survey. Scars were digitally added in different locations and orientations for a total of 14 unique scars added to each face. Each participant rated 50 different faces on confidence, friendliness, and attractiveness. Data were analyzed using linear mixed effects models. Results: A total of 88,850 ratings [82,990 scarred (93.4 percent)] for attractiveness, friendliness, and confidence were analyzed. In univariate linear mixed effects models, the presence of a facial scar did not significantly impact attractiveness (β = 0.016, SE = 0.014, z = 1.089, p = 0.276). A second set of linear mixed effects models identified interactions between location, subunit placement, and orientation to facial tension lines. Scars located on the lower lid mid subunit perpendicular to facial tension lines were rated less attractive (β = −0.065, SE = 0.028, z = −2.293, p = 0.022). Conclusions: On average, a single well-healed facial scar does not negatively affect first impressions of attractiveness, confidence, or friendliness. Specific scar location and orientation combinations, however, such as a perpendicular scar at the mid-lower eyelid, may result in lower perceived attractiveness, confidence, and friendliness

    The Earth Regeneration Effect of Solar Neutrinos: a Numerical Treatment with Three Active Neutrino Flavors

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    We introduce an integrated algorithm for full scale investigation of the earth regeneration effect of solar neutrinos with all three active neutrinos. We illustrate that the earth effect on low energy solar neutrinos (Eν<20E_\nu < 20 MeV) causes large variations in the survival probabilities for large values of the mixing angle θ12\theta_{12} for a given value of θ13\theta_{13}. But it is maximal for small values of θ13\theta_{13} and diminishes for large values at a given value of θ12\theta_{12}. The nadir angle dependence is sensitive to the value of EE/Δ12E'\equiv E/\Delta_{12}. As far as low energy solar neutrinos are concerned we notice that the earth effect is more pronounced for core penetration. We confirm that the earth effect leaves the SMA region almost intact regardless of θ13\theta_{13} and that it is significant for high energy 8^8B and hephep neutrinos in the LMA region. We also show that for large values of θ13\theta_{13}, the earth effect is significant for high energy neutrinos (E109E'\gtrsim 10^9) and it can be large at any nadir angle.Comment: 8 pages, 2 postscript figure

    A Study of the Day - Night Effect for the Super - Kamiokande Detector: I. Time Averaged Solar Neutrino Survival Probability

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    This is the first of two articles aimed at providing comprehensive predictions for the day-night (D-N) effect for the Super-Kamiokande detector in the case of the MSW \nu_e \to \numt transition solution of the solar neutrino problem. The one-year averaged probability of survival of the solar \nue crossing the Earth mantle, the core, the inner 2/3 of the core, and the (core + mantle) is calculated with high precision (better than 1%) using the elliptical orbit approximation (EOA) to describe the Earth motion around the Sun. Results for the survival probability in the indicated cases are obtained for a large set of values of the MSW transition parameters Δm2\Delta m^2 and sin22θVsin^22\theta_{V} from the ``conservative'' regions of the MSW solution, derived by taking into account possible relatively large uncertainties in the values of the 8^{8}B and 7^{7}Be neutrino fluxes. Our results show that the one-year averaged D-N asymmetry in the νe\nu_e survival probability for neutrinos crossing the Earth core can be, in the case of sin22θV0.13sin^22 \theta_{V} \leq 0.13, larger than the asymmetry in the probability for (only mantle crossing + core crossing) neutrinos by a factor of up to six. The enhancement is larger in the case of neutrinos crossing the inner 2/3 of the core. This indicates that the Super-Kamiokande experiment might be able to test the sin22θV0.01sin^22\theta_{V} \leq 0.01 region of the MSW solution of the solar neutrino problem by performing selective D-N asymmetry measurements.Comment: LaTeX2e - 18 Text Pages + 21 figures = 39 Pages. - Figures in PS + text file sk1b14.tex requires two auxiliary files (included

    The Earth Effect in the MSW Analysis of the Solar Neutrino Experiments

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    We consider the Earth effect in the MSW analysis of the Homestake, Kamiokande, GALLEX, and SAGE solar neutrino experiments. Using the time-averaged data and assuming two-flavor oscillations, the large-angle region of the combined fit extends to much smaller angles (to sin22θ0.1\sin^22\theta \simeq 0.1) than when the Earth effect is ignored. However, the additional constraint from the Kamiokande II day-night data excludes most of the parameter space sensitive to the Earth effect independent of astrophysical uncertainties, and leaves only a small large-angle region close to maximal mixing at 90\% C.L. The nonadiabatic solution remains unaffected by the Earth effect and is still preferred. Both theoretical and experimental uncertainties are included in the analysis.Comment: (11 pages, Revtex 3.0 (can be changed to Latex), 3 postscript figures included, UPR-0570T

    The structures and biological activities of the lipo-oligosaccharide nodulation signals produced by type I and II strains of Bradyrhizobium japonicum

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    Bradyrhizobium japonicum produces lipo-oligosaccharide signal molecules that induce deformation of root hairs and meristematic activity on soybeans. B. japonicum USDA135 (a Type I strain) produces modified chitin pentasaccharide molecules with either a terminal N-C16:0- or N-C18:1-glucosamine with and without an O-acetyl group at C-6 and with 2-O-methylfucose linked to C-6 of the reducing N-acetylglucosamine. An additional molecule has N-C16:1-glucosamine and no O-acetyl group. All of these molecules cause root hair deformation on Vicia sativa and Glycine soja. The C18:1-containing molecules were tested and found to induce meristem formation on G. soja. USDA61 (a Type II strain) produces eight additional molecules. Five have a carbamoyl group on the terminal N-acylglucosamine. Six have chitin tetrasaccharide backbones. Three have a terminal N-acyl-N-methylglucosaminosyl residue. In four molecules, the reducing-end N-acetylglucosamine is glycosidically linked to glycerol and has a branching fucosyl, rather than a 2-O-methylfucosyl, residue. One molecule has a terminal N-acylglucosamine that has both acetyl and carbamoyl groups (one each).Plant science
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