363 research outputs found
Evaluation of Aedes aegypti densonucleosis (AeDNV) infection in adult mosquito mortality
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
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
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 . 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
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 . 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?
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
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 (
MeV) causes large variations in the survival probabilities for large values of
the mixing angle for a given value of . But it is
maximal for small values of and diminishes for large values at a
given value of . The nadir angle dependence is sensitive to the
value of . 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 and that it is significant for high energy
B and neutrinos in the LMA region. We also show that for large values
of , the earth effect is significant for high energy neutrinos
() 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
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 and
from the ``conservative'' regions of the MSW solution,
derived by taking into account possible relatively large uncertainties in the
values of the B and Be neutrino fluxes. Our results show that the
one-year averaged D-N asymmetry in the survival probability for
neutrinos crossing the Earth core can be, in the case of , 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
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
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 ) 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
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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