The unknown constituents of the interior of our home planet have provoked the human imagination and driven scientific exploration. We herein demonstrate that large neutrino detectors could be used in ...the near future to significantly improve our understanding of the Earth's inner chemical composition. Neutrinos, which are naturally produced in the atmosphere, traverse the Earth and undergo oscillations that depend on the Earth's electron density. The Earth's chemical composition can be determined by combining observations from large neutrino detectors with seismic measurements of the Earth's matter density. We present a method that will allow us to perform a measurement that can distinguish between composition models of the outer core. We show that the next-generation large-volume neutrino detectors can provide sufficient sensitivity to reject extreme cases of outer core composition. In the future, dedicated instruments could be capable of distinguishing between specific Earth composition models and thereby reshape our understanding of the inner Earth in previously unimagined ways.
Abstract
In-situ measurements of soil water content provide important constraints on local/global hydrology. We demonstrate that the attenuation of the underground flux of cosmic-ray electromagnetic ...(EM) particles can be used to monitor the variation of soil water content after rainfalls. We developed a detection system that preferably selects EM particles by considering the coincidence of distant plastic scintillators. The calibration test beneath the water pool revealed that the count rate decreased by 0.6–0.7% with a 1 cm increase in the water level. The field measurement performed in the horizontal tunnel showed that the count rate dropped according to 48-h precipitation, after correcting the effects originating from atmospheric and water vapour pressures. These characteristics were confirmed using dedicated Monte Carlo simulations. This new method is called cosmic electromagnetic particle (CEMP) radiography.
•We discuss the phenomenon of allorecognition in context of the evolution of immunity in the metazoa.•Recent findings on allorecognition in the colonial ascidian, Botryllus schlosseri are ...reviewed.•Potential models for allo-specificity in B. schlosseri are presented.
Allorecognition has been well-studied in the context of vertebrate adaptive immunity and recognition of the Major Histocompatibility Complex (MHC), which is the central event of vertebrate immune responses. Although allorecognition systems have been identified throughout the metazoa, recent results have shown that there is no apparent conservation or orthologous relationship between the mechanisms underlying this phenomenon in different organisms. Thus the origin of the vertebrate adaptive immune system as well as these other complex recognition systems is a complete mystery. This review will focus on allorecognition in Botryllus schlosseri, a basal chordate which undergoes a natural transplantation reaction following contact between two individuals, and, analogous to vertebrates, is controlled by a single locus. We will summarize each of the known candidate genes within this locus and their potential roles in allorecognition, and speculate on how these findings may in fact be revealing potential functional relationships between disparate allorecognition systems.
We report on a measurement of the cosmic ray energy spectrum by the Telescope Array Low-Energy Extension (TALE) air fluorescence detector (FD). The TALE air FD is also sensitive to the Cherenkov ...light produced by shower particles. Low-energy cosmic rays, in the PeV energy range, are detectable by TALE as Cherenkov events. Using these events, we measure the energy spectrum from a low energy of ∼2 PeV to an energy greater than 100 PeV. Above 100 PeV, TALE can detect cosmic rays using air fluorescence. This allows for the extension of the measurement to energies greater than a few EeV. In this paper, we describe the detector, explain the technique, and present results from a measurement of the spectrum using ∼1000 hr of observation. The observed spectrum shows a clear steepening near 1017.1 eV, along with an ankle-like structure at 1016.2 eV. These features present important constraints on the origin of galactic cosmic rays and on propagation models. The feature at 1017.1 eV may also mark the end of the galactic cosmic ray flux and the start of the transition to extragalactic sources.
Since 2007, the Telescope Array (TA) experiment, based in Utah, USA, has been observing ultra high energy cosmic rays to understand their origins. The experiment includes a surface detector (SD) ...array and three fluorescence detector (FD) stations. The FD stations, installed surrounding the SD array, measure the air fluorescence light emitted from extensive air showers (EASs) for precise determination of their energies and species. The detectors employed at one of the three FD stations were relocated from the High Resolution Fly's Eye (HiRes) experiment. At the other two stations, newly designed detectors were constructed for the TA experiment. An FD consists of a primary mirror and a camera equipped with photomultiplier tube pixels. To obtain the EAS parameters with high accuracy, understanding the FD optical characteristics is important. In this paper, we report the characteristics and installation of the new FDs and the performances of the FD components. The results of the monitored mirror reflectance during the observation time are also described in this report.
Abstract
We report on a measurement of the cosmic-ray composition by the Telescope Array Low-energy Extension (TALE) air fluorescence detector (FD). By making use of the Cherenkov light signal in ...addition to air fluorescence light from cosmic-ray (CR)-induced extensive air showers, the TALE FD can measure the properties of the cosmic rays with energies as low as ∼2 PeV and exceeding 1 EeV. In this paper, we present results on the measurement of
distributions of showers observed over this energy range. Data collected over a period of ∼4 yr were analyzed for this study. The resulting
distributions are compared to the Monte Carlo (MC) simulated data distributions for primary cosmic rays with varying composition and a four-component fit is performed. The comparison and fit are performed for energy bins, of width 0.1 or 0.2 in
, spanning the full range of the measured energies. We also examine the mean
value as a function of energy for cosmic rays with energies greater than 10
15.8
eV. Below 10
17.3
eV, the slope of the mean
as a function of energy (the elongation rate) for the data is significantly smaller than that of all elements in the models, indicating that the composition is becoming heavier with energy in this energy range. This is consistent with a rigidity-dependent cutoff of events from Galactic sources. Finally, an increase in the
elongation rate is observed at energies just above 10
17
eV, indicating another change in the cosmic-ray composition.
The source of tissue turnover during homeostasis or following injury is usually due to proliferation of a small number of resident, lineage-restricted stem cells that have the ability to amplify and ...differentiate into mature cell types. We are studying vascular regeneration in a chordate model organism, Botryllus schlosseri, and have previously found that following surgical ablation of the extracorporeal vasculature, new tissue will regenerate in a VEGF-dependent process within 48 hrs. Here we use a novel vascular cell lineage tracing methodology to assess regeneration in parabiosed individuals and demonstrate that the source of regenerated vasculature is due to the proliferation of pre-existing vascular resident cells and not a mobile progenitor. We also show that these cells are bi-potential, and can reversibly adopt two fates, that of the newly forming vessels or the differentiated vascular tissue at the terminus of the vasculature, known as ampullae. In addition, we show that pre-existing vascular resident cells differentially express progenitor and differentiated cell markers including the Botryllus homologs of CD133, VEGFR-2, and Cadherin during the regenerative process.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Motivated by the detection of a significant dipole structure in the arrival directions of ultra-high-energy cosmic rays above 8 EeV reported by the Pierre Auger Observatory (Auger), we search for a ...large-scale anisotropy using data collected with the surface detector array of the Telescope Array Experiment (TA). With 11 yr of TA data, a dipole structure in a projection of the R.A. is fitted with an amplitude of 3.3% 1.9% and a phase of 131° 33°. The corresponding 99% confidence-level upper limit on the amplitude is 7.3%. At the current level of statistics, the fitted result is compatible with both an isotropic distribution and the dipole structure reported by Auger.
The basal chordate Botryllus schlosseri undergoes a natural transplantation reaction governed by a single, highly polymorphic locus called the fuhc. Our initial characterization of this locus ...suggested it encoded a single gene alternatively spliced into two transcripts: a 555 amino acid-secreted form containing the first half of the gene, and a full-length, 1008 amino acid transmembrane form, with polymorphisms throughout the ectodomain determining outcome. We have now found that the locus encodes two highly polymorphic genes which are separated by a 227 bp intergenic region: first, the secreted form as previously described, and a second gene encoding a 531 amino acid membrane-bound gene containing three extracellular immunoglobulin domains. While northern blotting revealed only these two mRNAs, both PCR and mRNA-seq detect a single capped and polyadenylated transcript that encodes processed forms of both genes linked by the intergenic region, as well as other transcripts in which exons of the two genes are spliced together. These results might suggest that the two genes are expressed as an operon, during which both genes are co-transcribed and then trans-spliced into two separate messages. This type of transcriptional regulation has been described in tunicates previously; however, the membrane-bound gene does not encode a typical Splice Leader (SL) sequence at the 5' terminus that usually accompanies trans-splicing. Thus, the presence of stable transcripts encoding both genes may suggest a novel mechanism of regulation, or conversely may be rare but stable transcripts in which the two mRNAs are linked due to a small amount of read-through by RNA polymerase. Both genes are highly polymorphic and co-expressed on tissues involved in histocompatibility. In addition, polymorphisms on both genes correlate with outcome, although we have found a case in which it appears that the secreted form may be major allorecognition determinant.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The purpose of the MU-RAY project is to develop an innovative approach to the study of volcanoes and their monitoring based on a particle physics approach. The test site is Vesuvio: one of the higher ...risk volcanoes in the world. In this context, muon radiography is an innovative method of enormous impact. This is an imaging technique which relies on the measurement, by means of a cosmic ray telescope, of the absorption in the volcano of muons with near-horizontal trajectories, produced by the interactions of cosmic rays with the atmosphere. Since 2003 this technique has been successfully used on volcanoes in Japan, providing pictures of their vertices with resolutions much better than those obtained with the traditional techniques based on gravimeters. Researchers from Naples and Florence are currently involved in the construction and testing of a prototype telescope based on the use of bars of plastic scintillator with a triangular section whose scintillation light is collected by special fibres (wave length shifters) and transported to SiPM (Silicon photomultipliers). A complete prototype telescope, consisting of three xy scintillation planes and 1m2 active area has been assembled and is now under test.
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