Simulation of UHE muons propagation for GEANT3

A simulation package for the transport of high energy muons has been developed. It has been conceived to replace the muon propagation software modules implemented in the detector simulation program GEANT3. Here we discuss the results achieved with our package and we check the agreement with numerical calculations up to 10**8 GeV.Comment: 21 pages, 6 figures, 1 Table. AMSTeX document, acknowledgments adde

Alternative RNA Splicing of the NMDA Receptor NR1 mRNA in the Neurons of the Teleost Electrosensory System

The sequence for cDNA encoding the NMDA receptor subunit 1 (aptNR1) of the weakly electric fish Apteronotus leptorhynchus has been determined. The deduced amino acid sequence is approximately 88% identical to other vertebrate NR1 proteins, with sequence homology extending to the alternatively spliced cassettes N1 and C1. The fish and mammalian N1 and C1 splice cassettes are identical at 20 of 21 and 30 of 37 amino acid positions, respectively. We did not detect a C2 splice cassette in aptNR1 mRNA, but we did find two novel C-terminal alternative splice cassettes labeled C1' and C1". The relative levels of NR1 transcripts containing the N1 and C1 splice cassettes were determined by using RNase protection and in situ hybridization analysis. N1-containing mRNAs are more abundant in caudal brain regions, similar to the patterns reported for mammalian brain. In contrast, the relative levels of transcripts containing the C1 splice cassette are much lower in fish than in mammals, averaging only 9% for the whole brain. The levels of C1 splicing increased in more rostral brain regions. In situ hybridizations with N1- and C1-specific probes demonstrated that N1 cassette splicing occurs in most neurons but that C1 splicing is heterogeneous and is restricted to a subset of neuronal types in the electrosensory system

Molecular biology of the apteronotus NMDA receptor NR1 subunit

The complete sequences and expression patterns of the NR1 (aptNR1) subunit of the N-methyl-d-aspartate (NMDA) receptor and its alternative splice isoforms have been determined for the weakly electric fish Apteronotus leptorhynchus. The deduced amino acid sequence of aptNR1 is approximately 88 % identical to the NR1 sequences of other vertebrate. Two of the three alternative splice cassettes previously described for mammalian NR1s, N1 and C1, are present in aptNR1, but the third cassette, C2, is not found. In addition, two teleost-specific splice cassettes occur on the N-terminal side of the C1 sequence. The cellular patterns of aptNR1 expression, including the patterns of N1 and C1 splicing, have been mapped using the in situ hybridization technique. High levels of aptNR1 mRNA were detected throughout the central nervous system including most neurons of the electrosensory system, with the highest levels in electrosensory lateral line lobe pyramidal cells. Expression of the N1 splice isoform was higher in more caudal regions of the brain, and expression of the C1 splice isoform was higher in more rostral regions. The N1 splice isoform was present in almost all NR1-positive cells, in contrast to the C1 splice isoform which was restricted to a subset of NR1-positive cells. These results demonstrate that the NR1 subunit of the NMDA receptor is evolutionarily conserved across species and that regulation of alternative RNA splicing modulates the properties of NR1 in different neurons of the central nervous system of A. leptorhynchus

Spatial and Temporal Dust Source Variability in Northern China Identified Using Advanced Remote Sensing Analysis

The aim of this research is to provide a detailed characterization of spatial patterns and temporal trends in the regional and local dust source areas within the desert of the Alashan Prefecture (Inner Mongolia, China). This problem was approached through multi-scale remote sensing analysis of vegetation changes. The primary requirements for this regional analysis are high spatial and spectral resolution data, accurate spectral calibration and good temporal resolution with a suitable temporal baseline. Landsat analysis and field validation along with the low spatial resolution classifications from MODIS and AVHRR are combined to provide a reliable characterization of the different potential dust-producing sources. The representation of intra-annual and inter-annual Normalized Difference Vegetation Index (NDVI) trend to assess land cover discrimination for mapping potential dust source using MODIS and AVHRR at larger scale is enhanced by Landsat Spectral Mixing Analysis (SMA). The combined methodology is to determine the extent to which Landsat can distinguish important soils types in order to better understand how soil reflectance behaves at seasonal and inter-annual timescales. As a final result mapping soil surface properties using SMA is representative of responses of different land and soil cover previously identified by NDVI trend. The results could be used in dust emission models even if they are not reflecting aggregate formation, soil stability or particle coatings showing to be critical for accurately represent dust source over different regional and local emitting areas

Spatial Resolution of Double-Sided Silicon Microstrip Detectors for the PAMELA Apparatus

The PAMELA apparatus has been assembled and it is ready to be launched in a satellite mission to study mainly the antiparticle component of cosmic rays. In this paper the performances obtained for the silicon microstrip detectors used in the magnetic spectrometer are presented. This subdetector reconstructs the curvature of a charged particle in the magnetic field produced by a permanent magnet and consequently determines momentum and charge sign, thanks to a very good accuracy in the position measurements (better than 3 um in the bending coordinate). A complete simulation of the silicon microstrip detectors has been developed in order to investigate in great detail the sensor's characteristics. Simulated events have been then compared with data gathered from minimum ionizing particle (MIP) beams during the last years in order to tune free parameters of the simulation. Finally some either widely used or original position finding algorithms, designed for such kind of detectors, have been applied to events with different incidence angles. As a result of the analysis, a method of impact point reconstruction can be chosen, depending on both the particle's incidence angle and the cluster multiplicity, so as to maximize the capability of the spectrometer in antiparticle tagging.Comment: 28 pages, 18 figures, submitted to Nuclear Instruments and Methods in Physics Research

Effect of thyroglobulin autoantibodies on the metabolic clearance of serum thyroglobulin

Background: In order to establish whether thyroglobulin autoantibodies (TgAb) influence the metabolic clearance of thyroglobulin (Tg) in humans, serum Tg and TgAb were correlated shortly after radioiodine (131I) treatment. Methods: Samples were collected from 30 consecutive patients undergoing 131I activity for Graves' hyperthyroidism at the time of treatment and every 15 days thereafter, up to 90 days. Tg and TgAb were measured by immunometric assays (functional sensitivities: 0.1 ng/mL and 8 IU/mL). Results: Tg was detectable in all patients at day 0. Tg concentrations rose from a mean of 33.2 ng/mL [confidence interval (CI) 17.8–61.0 ng/mL] at day 0 to a mean of 214.6 ng/mL [CI 116.9–393.4 ng/mL] at day 30 and then steadily decreased, reaching the lowest concentration at day 90 (M = 10.9 ng/mL [CI 5.5–20.9 ng/mL]). Compared to their levels at day 0 (M = 23.6 IU/mL [CI 10.5–52.9 IU/mL]), TgAb remained stable through day 15 and then gradually increased up to a mean of 116.6 IU/mL [CI 51.9–262.2 IU/mL] at day 90. Patients were then split into two groups according to their TgAb status at day 0: undetectable (<8 IU/mL; 9 patients) or detectable (≥8 IU/mL; 21 patients) TgAb. Compared to the other cohort, patients with detectable TgAb showed significantly lower Tg concentrations at day 0 (M = 20.3 ng/mL [CI 10.1–40.2 ng/mL] vs. M = 101.8 ng/mL [CI 36.6–279.8 ng/mL]), similar at day 15, lower levels at day 30 (M = 146.5 ng/mL [CI 74.3–287.8 ng/mL] vs. M = 514.8 ng/mL [CI 187.8–1407.9 ng/mL]), at day 45 (M = 87.5 ng/mL [CI 43.1–176.6 ng/mL] vs. M = 337.9 ng/mL [CI 120.1–947.0 ng/mL]), at day 60 (M = 61.6 ng/mL [CI 31.0–121.4 ng/mL] vs. M = 255.8 ng/mL [CI 79.0–823.8 ng/mL]), and at day 75 (M = 24.5 ng/mL [CI 11.9–49.2 ng/mL] vs. M = 249.5 ng/mL [CI 63.5–971.1 ng/mL]), and similar levels at day 90. Patients with detectable TgAb showed a lower (M = 182.5 ng/mL [CI 92.0–361.0 ng/mL] vs. M = 514.8 ng/mL [CI 187.8–1407.9 ng/mL]) and an earlier (day 15 vs. day 30) peak of Tg. The mean Tg concentration was lower in patients with detectable TgAb than in those with undetectable TgAb (area under the curve: 17,340 ± 16,481 ng/mL vs. 36,883 ± 44,625 ng/mL; p = 0.02). Conclusions: TgAb influence the changes in Tg concentrations observed immediately after 131I treatment, inducing lower levels and an earlier peak of Tg. These observations indicate that TgAb significantly influence the metabolic clearance of Tg, supporting the concept that their interference in the measurement of Tg is mainly due to an in vivo effect

NLO corrections to ultra-high energy neutrino-nucleon scattering, shadowing and small x

We reconsider the Standard Model interactions of ultra-high energy neutrinos with matter. The next to leading order QCD corrections are presented for charged-current and neutral-current processes. Contrary to popular expectations, these corrections are found to be quite substantial, especially for very large (anti-) neutrino energies. Hence, they need to be taken into account in any search for new physics effects in high-energy neutrino interactions. In our extrapolation of the parton densities to kinematical regions as yet unexplored directly in terrestrial accelerators, we are guided by double asymptotic scaling in the large Q^2 and small Bjorken x region and to models of saturation in the low Q^2 and low x regime. The sizes of the consequent uncertainties are commented upon. We also briefly discuss some variables which are insensitive to higher order QCD corrections and are hence suitable in any search for new physics.Comment: 21 pages, LaTeX2e, uses JHEP3.cls (included), 8 ps files for figures published versio

EUSO science

EUSO is a mission to explore the extreme universe by the probe of Ultra High Energy Cosmic Rays (UHECRs) and UHE neutrinos. EUSO monitors a gigantic volume of atmosphere from Space and measures showers induced by UHECRs and UHE neutrinos. Scientifically, it is important to measure the energy spectrum of UHECRs well beyond GZK energy with high statistics. EUSO ensures the observation of UHECRs up to 10$^{21}$eV even in the case of GZK mechanism working, and gives us a clear picture of the existence / non-existence of the GZK effect and the behavior of the spectrum beyond GZK energy, which represents the contributions from nearby sources. The anisotropy study of UHECR arrival directions in a small scale angle above GZK energy may allow us to identify individual source, because of the limited propagation distance and the high rigidity of particles. If event clusters observed by AGASA are real, it is expected from Monte Carlo simulation that EUSO will see ~100 particles from individual brightest sources and will give us a good opportunity to test the relativity in high precision. The UHE neutrino is a unique channel to explore the universe much deeper than UHECRs. EUSO essentially can measure UHE neutrinos free from background proton showers. The number of GZK neutrino events in a EUSO three years' mission is expected to be only a few. Nevertheless, it is a definitely conceivable opportunity to begin UHE neutrino astrophysics at GZK energy

Two years of flight of the Pamela experiment: results and perspectives

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antinuclei with a precision of the order of $10^{-8}$). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, $15^{th}$ 2006 in a $350\times 600 km$ orbit with an inclination of 70 degrees. In this work we describe the scientific objectives and the performance of PAMELA in its first two years of operation. Data on protons of trapped, secondary and galactic nature - as well as measurements of the December $13^{th}$ 2006 Solar Particle Event - are also provided.Comment: To appear on J. Phys. Soc. Jpn. as part of the proceedings of the International Workshop on Advances in Cosmic Ray Science March, 17-19, 2008 Waseda University, Shinjuku, Tokyo, Japa

Propagation of Muons and Taus at High Energies

The photonuclear contribution to charged lepton energy loss has been re-evaluated taking into account HERA results on real and virtual photon interactions with nucleons. With large $Q^2$ processes incorporated, the average muon range in rock for muon energies of $10^9$ GeV is reduced by only 5% as compared with the standard treatment. We have calculated the tau energy loss for energies up to $10^9$ GeV taking into consideration the decay of the tau. A Monte Carlo evaluation of tau survival probability and range show that at energies below $10^7-10^8$ GeV, depending on the material, only tau decays are important. At higher energies the tau energy losses are significant, reducing the survival probability of the tau. We show that the average range for tau is shorter than its decay length and reduce to 17 km in water for an incident tau energy of $10^9$ GeV, as compared with its decay length of 49 km at that energy. In iron, the average tau range is 4.7 km for the same incident energy.Comment: 25 pages including 8 figure