192 research outputs found
Interpretation of neutrino flux limits from neutrino telescopes on the Hillas plot
We discuss the interplay between spectral shape and detector response beyond
a simple E^-2 neutrino flux at neutrino telescopes, at the example of
time-integrated point source searches using IceCube-40 data. We use a
self-consistent model for the neutrino production, in which protons interact
with synchrotron photons from co-accelerated electrons, and we fully take into
account the relevant pion and kaon production modes, the flavor composition at
the source, flavor mixing, and magnetic field effects on the secondaries
(pions, muon, and kaons). Since some of the model parameters can be related to
the Hillas parameters R (size of the acceleration region) and B (magnetic
field), we relate the detector response to the Hillas plane. In order to
compare the response to different spectral shapes, we use the energy flux
density as a measure for the pion production efficiency times luminosity of the
source. We demonstrate that IceCube has a very good reach in this quantity for
AGN nuclei and jets for all source declinations, while the spectra of sources
with strong magnetic fields are found outside the optimal reach. We also
demonstrate where neutrinos from kaon decays and muon tracks from tau decays
can be relevant for the detector response. Finally, we point out the
complementarity between IceCube and other experiments sensitive to high-energy
neutrinos, at the example of 2004-2008 Earth-skimming neutrino data from Auger.
We illustrate that Auger, in principle, is better sensitive to the parameter
region in the Hillas plane from which the highest-energetic cosmic rays may be
expected in this model.Comment: 28 pages, 10 figures. Substantial clarifications, such as on
definition of "sensitivity" and model descriptio
Non-invasive genetic monitoring for the threatened valley elderberry longhorn beetle.
The valley elderberry longhorn beetle (VELB), Desmocerus californicus dimorphus (Coleoptera: Cerambycidae), is a federally threatened subspecies endemic to the Central Valley of California. The VELB range partially overlaps with that of its morphologically similar sister taxon, the California elderberry longhorn beetle (CELB), Desmocerus californicus californicus (Coleoptera: Cerambycidae). Current surveying methods are limited to visual identification of larval exit holes in the VELB/CELB host plant, elderberry (Sambucus spp.), into which larvae bore and excavate feeding galleries. Unbiased genetic approaches could provide a much-needed complementary approach that has more precision than relying on visual inspection of exit holes. In this study we developed a DNA sequencing-based method for indirect detection of VELB/CELB from frass (insect fecal matter), which can be easily and non-invasively collected from exit holes. Frass samples were collected from 37 locations and the 12S and 16S mitochondrial genes were partially sequenced using nested PCR amplification. Three frass-derived sequences showed 100% sequence identity to VELB/CELB barcode references from museum specimens sequenced for this study. Database queries of frass-derived sequences also revealed high similarity to common occupants of old VELB feeding galleries, including earwigs, flies, and other beetles. Overall, this non-invasive approach is a first step towards a genetic assay that could augment existing VELB monitoring and accurately discriminate between VELB, CELB, and other insects. Furthermore, a phylogenetic analysis of 12S and 16S data from museum specimens revealed evidence for the existence of a previously unrecognized, genetically distinct CELB subpopulation in southern California
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Transcriptional Response to Acute Thermal Exposure in Juvenile Chinook Salmon Determined by RNAseq.
Thermal exposure is a serious and growing challenge facing fish species worldwide. Chinook salmon (Oncorhynchus tshawytscha) living in the southern portion of their native range are particularly likely to encounter warmer water due to a confluence of factors. River alterations have increased the likelihood that juveniles will be exposed to warm water temperatures during their freshwater life stage, which can negatively impact survival, growth, and development and pose a threat to dwindling salmon populations. To better understand how acute thermal exposure affects the biology of salmon, we performed a transcriptional analysis of gill tissue from Chinook salmon juveniles reared at 12° and exposed acutely to water temperatures ranging from ideal to potentially lethal (12° to 25°). Reverse-transcribed RNA libraries were sequenced on the Illumina HiSeq2000 platform and a de novo reference transcriptome was created. Differentially expressed transcripts were annotated using Blast2GO and relevant gene clusters were identified. In addition to a high degree of downregulation of a wide range of genes, we found upregulation of genes involved in protein folding/rescue, protein degradation, cell death, oxidative stress, metabolism, inflammation/immunity, transcription/translation, ion transport, cell cycle/growth, cell signaling, cellular trafficking, and structure/cytoskeleton. These results demonstrate the complex multi-modal cellular response to thermal stress in juvenile salmon
Discovery of genes implicated in whirling disease infection and resistance in rainbow trout using genome-wide expression profiling
<p>Abstract</p> <p>Background</p> <p>Whirling disease, caused by the pathogen <it>Myxobolus cerebralis</it>, afflicts several salmonid species. Rainbow trout are particularly susceptible and may suffer high mortality rates. The disease is persistent and spreading in hatcheries and natural waters of several countries, including the U.S.A., and the economic losses attributed to whirling disease are substantial. In this study, genome-wide expression profiling using cDNA microarrays was conducted for resistant Hofer and susceptible Trout Lodge rainbow trout strains following pathogen exposure with the primary objective of identifying specific genes implicated in whirling disease resistance.</p> <p>Results</p> <p>Several genes were significantly up-regulated in skin following pathogen exposure for both the resistant and susceptible rainbow trout strains. For both strains, response to infection appears to be linked with the interferon system. Expression profiles for three genes identified with microarrays were confirmed with qRT-PCR. <it>Ubiquitin-like protein 1 </it>was up-regulated over 100 fold and <it>interferon regulating factor 1 </it>was up-regulated over 15 fold following pathogen exposure for both strains. Expression of <it>metallothionein B</it>, which has known roles in inflammation and immune response, was up-regulated over 5 fold in the resistant Hofer strain but was unchanged in the susceptible Trout Lodge strain following pathogen exposure.</p> <p>Conclusion</p> <p>The present study has provided an initial view into the genetic basis underlying immune response and resistance of rainbow trout to the whirling disease parasite. The identified genes have allowed us to gain insight into the molecular mechanisms implicated in salmonid immune response and resistance to whirling disease infection.</p
The neutrino velocity anomaly as an explanation of the missing observation of neutrinos in coincidence with GRB
The search for neutrinos emitted in coincidence with Gamma-Bay Burst has been
so far unsuccessfully. In this paper we show that the recent result reported by
the OPERA Collaboration on an early arrival time of muon neutrinos with respect
to the one computed assuming the speed of light in vacuum could explain the
null search for neutrinos in coincidence with Gamma-Ray Burst
The Mare as a Model for Luteinized Unruptured Follicle Syndrome: Intrafollicular Endocrine Milieu.
Luteinized unruptured follicle (LUF) syndrome is a recurrent anovulatory dysfunction that affects up to 23% of women with normal menstrual cycles and up to 73% with endometriosis. Mechanisms underlying the development of LUF syndrome in mares were studied to provide a potential model for human anovulation. The effect of extended increase in circulating LH achieved by administration of recombinant equine LH (reLH) or a short surge of LH and decrease in progesterone induced by prostaglandin F2α (PGF2α) on LUF formation (Experiment 1), identification of an optimal dose of COX-2 inhibitor (flunixin meglumine, FM; to block the effect of prostaglandins) for inducing LUFs (Experiment 2), and evaluation of intrafollicular endocrine milieu in LUFs (Experiment 3) were investigated. In Experiment 1, mares were treated with reLH from Day 7 to Day 15 (Day 0=ovulation), PGF2α on Day 7, or in combination. In Experiment 2, FM at doses of 2.0 or 3.0 mg/kg every 12 h and human chorionic gonadotropin (hCG) (1500 IU) were administered after a follicle ≥32 mm was detected. In Experiment 3, FM at a dose of 2.0 mg/kg every 12 h plus hCG was used to induce LUFs and investigate the intrafollicular endocrine milieu. No LUFs were induced by reLH or PGF2α treatment; however, LUFs were induced in 100% of mares using FM. Intrafollicular PGF2α metabolite, PGF2α, and PGE2 were lower and the ratio of PGE2:PGF2α was higher in the induced LUF group. Higher levels of intrafollicular E2 and total primary sex steroids were observed in the induced LUF group along with a tendency for higher levels of GH, cortisol, and T; however, LH, PRL, VEGF-A, and NO did not differ between groups. In conclusion, this study reveals part of the intrafollicular endocrine milieu and the association of prostaglandins in LUF formation, and indicates that the mare might be an appropriate model for studying the poorly understood LUF syndrome
BPS states in M-theory and twistorial constituents
We provide a complete algebraic description of BPS states in M-theory in
terms of primary constituents that we call BPS preons. We argue that any BPS
state preserving of the 32 supersymmetries is a composite of (32-k) BPS
preons. In particular, the BPS states corresponding to the basic M2 and M5
branes are composed of 16 BPS preons. By extending the M-algebra to a
generalized D=11 conformal superalgebra we relate the BPS preons
with its fundamental representation, the D=11 supertwistors.Comment: 4 pages. Refs. updated, two cosmetic changes, to appear in PR
The metric and strong coupling limit of the M5-brane
We find the analogue of the Boillat metric of Born-Infeld theory for the
M5-brane. We show that it provides the propagation cone of {\sl all} 5-brane
degrees. In an arbitrary background field, this cone never lies outside the
Einstein cone. An energy momentum tensor for the three-form is defined and
shown to satisfy the Dominant Energy Condition. The theory is shown to be well
defined for all values of the magnetic field but there is a limiting electric
field strength. We consider the strong coupling limit of the M5-brane and show
that the corresponding theory is conformally invariant and admits infinitely
many conservation laws. On reduction to the Born-Infeld case this agrees with
the work of Bia{\l}nicki-Birula.Comment: Version to be published in special issue of JMP, July 2001. Sections
8 and 9 have been remove
The Mare as a Model for Luteinized Unruptured Follicle Syndrome: Intrafollicular Endocrine Milieu.
Luteinized unruptured follicle (LUF) syndrome is a recurrent anovulatory dysfunction that affects up to 23% of women with normal menstrual cycles and up to 73% with endometriosis. Mechanisms underlying the development of LUF syndrome in mares were studied to provide a potential model for human anovulation. The effect of extended increase in circulating LH achieved by administration of recombinant equine LH (reLH) or a short surge of LH and decrease in progesterone induced by prostaglandin F2α (PGF2α) on LUF formation (Experiment 1), identification of an optimal dose of COX-2 inhibitor (flunixin meglumine, FM; to block the effect of prostaglandins) for inducing LUFs (Experiment 2), and evaluation of intrafollicular endocrine milieu in LUFs (Experiment 3) were investigated. In Experiment 1, mares were treated with reLH from Day 7 to Day 15 (Day 0=ovulation), PGF2α on Day 7, or in combination. In Experiment 2, FM at doses of 2.0 or 3.0 mg/kg every 12 h and human chorionic gonadotropin (hCG) (1500 IU) were administered after a follicle ≥32 mm was detected. In Experiment 3, FM at a dose of 2.0 mg/kg every 12 h plus hCG was used to induce LUFs and investigate the intrafollicular endocrine milieu. No LUFs were induced by reLH or PGF2α treatment; however, LUFs were induced in 100% of mares using FM. Intrafollicular PGF2α metabolite, PGF2α, and PGE2 were lower and the ratio of PGE2:PGF2α was higher in the induced LUF group. Higher levels of intrafollicular E2 and total primary sex steroids were observed in the induced LUF group along with a tendency for higher levels of GH, cortisol, and T; however, LH, PRL, VEGF-A, and NO did not differ between groups. In conclusion, this study reveals part of the intrafollicular endocrine milieu and the association of prostaglandins in LUF formation, and indicates that the mare might be an appropriate model for studying the poorly understood LUF syndrome
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