336 research outputs found
Antigenic and genetic characterization of a divergent African virus, Ikoma lyssavirus
In 2009, a novel lyssavirus (subsequently named Ikoma lyssavirus, IKOV) was detected in the brain of an African civet (Civettictis civetta) with clinical rabies in the Serengeti National Park of Tanzania. The degree of nucleotide divergence between the genome of IKOV and those of other lyssaviruses predicted antigenic distinction from, and lack of protection provided by, available rabies vaccines. In addition, the index case was considered likely to be an incidental spillover event, and therefore the true reservoir of IKOV remained to be identified. The advent of sensitive molecular techniques has led to a rapid increase in the discovery of novel viruses. Detecting viral sequence alone, however, only allows for prediction of phenotypic characteristics and not their measurement. In the present study we describe the in vitro and in vivo characterization of IKOV, demonstrating that it is (1) pathogenic by peripheral inoculation in an animal model, (2) antigenically distinct from current rabies vaccine strains and (3) poorly neutralized by sera from humans and animals immunized against rabies. In a laboratory mouse model, no protection was elicited by a licensed rabies vaccine. We also investigated the role of bats as reservoirs of IKOV. We found no evidence for infection among 483 individuals of at least 13 bat species sampled across sites in the Serengeti and Southern Kenya
Measuring in Decays
We consider the possibility of measuring both and in the KM unitarity triangle using the process . This decay mode has a higher branching fraction (O(1%)) than
the mode . We use the factorization assumption and heavy
hadron chiral perturbation theory to estimate the branching fraction and
polarization. The time dependent rate for can be
used to measure and . Furthermore, examination
of the mass spectrum may be the best way to experimentally find
the broad p-wave meson.Comment: Revtex, 28 pages, 7 figures, title changed, introduction expanded,
added references, details of calculations moved to the appendi
International consensus statement on allergy and rhinology: Allergic rhinitis – 2023
Background
In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document. Methods
ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work. Results
ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost. Conclusion
The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment
B -> K^* gamma from D -> K^* l nu
The B -> K^* gamma branching fraction is predicted using heavy quark spin
symmetry at large recoil to relate the tensor and (axial-)vector form factors,
using heavy quark flavor symmetry to relate the B decay form factors to the
measured D -> K^* l nu form form factors, and extrapolating the semileptonic B
decay form factors to large recoil assuming nearest pole dominance. This
prediction agrees with data surprisingly well, and we comment on its
implications for the extraction of |Vub| from B -> rho l nu.Comment: 10 page
1951: Abilene Christian College Bible Lectures - Full Text
Delivered in the Auditorium of Abilene Christian College
Abilene, Texas
February 18-22, 1951
Price, $3.00
FIRM FOUNDATION PUBLISHING HOUSE
Austin, Texa
Physical Conditions in a Young, Unreddened, Low Metallicity Galaxy at High Redshift
Increasingly large samples of galaxies are now being discovered at redshifts
z~5-6 and higher. Many of these objects are inferred to be young, low in mass,
and relatively unreddened, but detailed analysis of their high quality spectra
will not be possible until the advent of future facilities. In this paper we
shed light on the physical conditions in a plausibly similar low mass galaxy by
presenting the analysis of the rest-frame optical and UV spectra of
Q2343-BX418, an L* galaxy at z=2.3 with a very low mass-to-light ratio and
unusual properties: BX418 is young (<100 Myr), low mass (M_star ~ 10^9 Msun),
low in metallicity (Z ~ 1/6 Zsun), and unreddened (E(B-V)~0.02, UV continuum
slope beta=-2.1). We infer a metallicity 12+log(O/H)=7.9 +/- 0.2 from the
rest-frame optical emission lines. We also determine the metallicity via the
direct, electron temperature method, using the ratio O III] 1661, 1666/[O III]
5007 to determine the electron temperature and finding 12+ log(O/H)=7.8 +/-
0.1. These measurements place BX418 among the most metal-poor galaxies observed
in emission at high redshift. The rest-frame UV spectrum contains strong
emission from Lya (with rest-frame equivalent width 54 A), He II 1640 (both
stellar and nebular), C III] 1907, 1909 and O III] 1661, 1666. The C IV/C III]
ratio indicates that the source of ionization is unlikely to be an AGN.
Analysis of the He II, O III] and C III] line strengths indicates a very high
ionization parameter log U ~ -1, while Lya and the interstellar absorption
lines indicate that outflowing gas is highly ionized over a wide range of
velocities. It remains to be determined how many of BX418's unique spectral
features are due to its global properties, such as low metallicity and dust
extinction, and how many are indicative of a short-lived phase in the early
evolution of an otherwise normal star-forming galaxy.Comment: Accepted for publication in ApJ. 28 pages, 14 figure
1936: Abilene Christian College Bible Lectures - Full Text
Delivered in the auditorium of Abilene Christian College, Abilene, Texas, February 193
Planet Sensitivity from Combined Ground- and Space-based Microlensing Observations
To move one step forward toward a Galactic distribution of planets, we
present the first planet sensitivity analysis for microlensing events with
simultaneous observations from space and the ground. We present this analysis
for two such events, OGLE-2014-BLG-0939 and OGLE-2014-BLG-0124, which both show
substantial planet sensitivity even though neither of them reached high
magnification. This suggests that an ensemble of low to moderate magnification
events can also yield significant planet sensitivity and therefore probability
to detect planets. The implications of our results to the ongoing and future
space-based microlensing experiments to measure the Galactic distribution of
planets are discussed.Comment: 10 pages, 5 figures, 1 table; ApJ in pres
B-->pi and B-->K transitions in standard and quenched chiral perturbation theory
We study the effects of chiral logs on the heavy-->light pseudoscalar meson
transition form factors by using standard and quenched chiral perturbation
theory combined with the static heavy quark limit. The resulting expressions
are used to indicate the size of uncertainties due to the use of the quenched
approximation in the current lattice studies. They may also be used to assess
the size of systematic uncertainties induced by missing chiral log terms in
extrapolating toward the physical pion mass. We also provide the coefficient
multiplying the quenched chiral log, which may be useful if the quenched
lattice studies are performed with very light mesons.Comment: 33 pages, 8 PostScript figures, version to appear in PR
Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.
Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology
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