One step growth of GaN/SiO2 core/shell nanowire in vapor-liquid-solid route by chemical vapor deposition technique

GaN/SiO2 core/shell nanowires are grown by cobalt phthalocyanine catalyst assisted vapor-liquid-solid route, in which Si wafer coated with a mixture of gallium and indium is used as the source for Ga and Si and ammonia is used as the precursor for nitrogen and hydrogen. Gallium in the presence of indium and hydrogen, which results from the dissociation of ammonia, forms Si-Ga-In alloy at the growth temperature around 910 degree Celsius. This alloy acts as the source of Si, Ga and In. A detailed study using a variety of characterization tools reveals that these wires, which are several tens of micron long, has a diameter distribution of the core ranging from 20 to 50 nm, while the thickness of the amorphous SiO2 shell layer is about 10 nm. These wires grow along direction. It has also been observed that the average width of these wires decreases, while their density increases as the gallium proportion in the Ga-In mixture is increased.Comment: 14 pages, 4 figure

Communicable Ulcerative Colitis Induced by T-bet Deficiency in the Innate Immune System

Inflammatory bowel disease (IBD) has been attributed to overexuberant host immunity or the emergence of harmful intestinal flora. The transcription factor T-bet orchestrates inflammatory genetic programs in both adaptive and innate immunity. We describe a profound and unexpected function for T-bet in influencing the behavior of host inflammatory activity and commensal bacteria. T-bet deficiency in the innate immune system results in spontaneous and communicable ulcerative colitis in the absence of adaptive immunity and increased susceptibility to colitis in immunologically intact hosts. T-bet controls the response of the mucosal immune system to commensal bacteria by regulating TNF-α production in colonic dendritic cells, critical for colonic epithelial barrier maintenance. Loss of T-bet influences bacterial populations to become colitogenic, and this colitis is communicable to genetically intact hosts. These findings reveal a novel function for T-bet as a peacekeeper of host-commensal relationships and provide new perspectives on the pathophysiology of IBD

PYTHIA hadronization process tuning in the GENIE neutrino interaction generator

9 pages, 7 figures, proceedings of the CETUP*-Workshop on Neutrino Interactions, July 22-31, 2014 at Lead/Dead Wood, South Dakota, USA9 pages, 7 figures, proceedings of the CETUP*-Workshop on Neutrino Interactions, July 22-31, 2014 at Lead/Dead Wood, South Dakota, USAv1: 9 pages, 7 figures, proceedings of the CETUP*-Workshop on Neutrino Interactions, July 22-31, 2014 at Lead/Dead Wood, South Dakota, USA. v2: 15 pages, 8 figures, 1 table, will be published by Journal of Physics G: Nuclear and Particle Physics (IoP

N- and C-Terminal Domains of the Calcium Binding Protein EhCaBP1 of the Parasite Entamoeba histolytica Display Distinct Functions

Entamoeba histolytica, a protozoan parasite, is the causative agent of amoebiasis, and calcium signaling is thought to be involved in amoebic pathogenesis. EhCaBP1, a Ca2+ binding protein of E. histolytica, is essential for parasite growth. High resolution crystal structure of EhCaBP1 suggested an unusual arrangement of the EF-hand domains in the N-terminal part of the structure, while C-terminal part of the protein was not traced. The structure revealed a trimer with amino terminal domains of the three molecules interacting in a head-to-tail manner forming an assembled domain at the interface with EF1 and EF2 motifs of different molecules coming close to each other. In order to understand the specific roles of the two domains of EhCaBP1, the molecule was divided into two halves, and each half was separately expressed. The domains were characterized with respect to their structure, as well as specific functional features, such as ability to activate kinase and bind actin. The domains were also expressed in E. histolytica cells along with green fluorescent protein. The results suggest that the N-terminal domain retains some of the properties, such as localization in phagocytic cups and activation of kinase. Crystal structure of EhCaBP1 with Phenylalanine revealed that the assembled domains, which are similar to Calmodulin N-terminal domain, bind to Phenylalanine revealing the binding mode to the target proteins. The C-terminal domain did not show any of the activities tested. However, over-expression in amebic cells led to a dominant negative phenotype. The results suggest that the two domains of EhCaBP1 are functionally and structurally different from each other. Both the domains are required for structural stability and full range of functional diversity

Mechanical design of the optical modules intended for IceCube-Gen2

IceCube-Gen2 is an expansion of the IceCube neutrino observatory at the South Pole that aims to increase the sensitivity to high-energy neutrinos by an order of magnitude. To this end, about 10,000 new optical modules will be installed, instrumenting a fiducial volume of about 8 km3. Two newly developed optical module types increase IceCube’s current sensitivity per module by a factor of three by integrating 16 and 18 newly developed four-inch PMTs in specially designed 12.5-inch diameter pressure vessels. Both designs use conical silicone gel pads to optically couple the PMTs to the pressure vessel to increase photon collection efficiency. The outside portion of gel pads are pre-cast onto each PMT prior to integration, while the interiors are filled and cast after the PMT assemblies are installed in the pressure vessel via a pushing mechanism. This paper presents both the mechanical design, as well as the performance of prototype modules at high pressure (70 MPa) and low temperature (−40∘C), characteristic of the environment inside the South Pole ice

The next generation neutrino telescope: IceCube-Gen2

The IceCube Neutrino Observatory, a cubic-kilometer-scale neutrino detector at the geographic South Pole, has reached a number of milestones in the field of neutrino astrophysics: the discovery of a high-energy astrophysical neutrino flux, the temporal and directional correlation of neutrinos with a flaring blazar, and a steady emission of neutrinos from the direction of an active galaxy of a Seyfert II type and the Milky Way. The next generation neutrino telescope, IceCube-Gen2, currently under development, will consist of three essential components: an array of about 10,000 optical sensors, embedded within approximately 8 cubic kilometers of ice, for detecting neutrinos with energies of TeV and above, with a sensitivity five times greater than that of IceCube; a surface array with scintillation panels and radio antennas targeting air showers; and buried radio antennas distributed over an area of more than 400 square kilometers to significantly enhance the sensitivity of detecting neutrino sources beyond EeV. This contribution describes the design and status of IceCube-Gen2 and discusses the expected sensitivity from the simulations of the optical, surface, and radio components

Sensitivity of IceCube-Gen2 to measure flavor composition of Astrophysical neutrinos

The observation of an astrophysical neutrino flux in IceCube and its detection capability to separate between the different neutrino flavors has led IceCube to constraint the flavor content of this flux. IceCube-Gen2 is the planned extension of the current IceCube detector, which will be about 8 times larger than the current instrumented volume. In this work, we study the sensitivity of IceCube-Gen2 to the astrophysical neutrino flavor composition and investigate its tau neutrino identification capabilities. We apply the IceCube analysis on a simulated IceCube-Gen2 dataset that mimics the High Energy Starting Event (HESE) classification. Reconstructions are performed using sensors that have 3 times higher quantum efficiency and isotropic angular acceptance compared to the current IceCube optical modules. We present the projected sensitivity for 10 years of data on constraining the flavor ratio of the astrophysical neutrino flux at Earth by IceCube-Gen2

Direction reconstruction performance for IceCube-Gen2 Radio

The IceCube-Gen2 facility will extend the energy range of IceCube to ultra-high energies. The key component to detect neutrinos with energies above 10 PeV is a large array of in-ice radio detectors. In previous work, direction reconstruction algorithms using the forward-folding technique have been developed for both shallow (≲20 m) and deep in-ice detectors, and have also been successfully used to reconstruct cosmic rays with ARIANNA. Here, we focus on the reconstruction algorithm for the deep in-ice detector, which was recently introduced in the context of the Radio Neutrino Observatory in Greenland (RNO-G)

Deep Learning Based Event Reconstruction for the IceCube-Gen2 Radio Detector

The planned in-ice radio array of IceCube-Gen2 at the South Pole will provide unprecedented sensitivity to ultra-high-energy (UHE) neutrinos in the EeV range. The ability of the detector to measure the neutrino’s energy and direction is of crucial importance. This contribution presents an end-to-end reconstruction of both of these quantities for both detector components of the hybrid radio array (\u27shallow\u27 and \u27deep\u27) using deep neural networks (DNNs). We are able to predict the neutrino\u27s direction and energy precisely for all event topologies, including the electron neutrino charged-current (νe-CC) interactions, which are more complex due to the LPM effect. This highlights the advantages of DNNs for modeling the complex correlations in radio detector data, thereby enabling a measurement of the neutrino energy and direction. We discuss how we can use normalizing flows to predict the PDF for each individual event which allows modeling the complex non-Gaussian uncertainty contours of the reconstructed neutrino direction. Finally, we discuss how this work can be used to further optimize the detector layout to improve its reconstruction performance