Abstract
Star-forming and starburst galaxies, which are well-known cosmic-ray reservoirs, are expected to emit gamma-rays and neutrinos predominantly via hadronic collisions. In this Letter, we ...analyze the 10 yr Fermi-LAT spectral energy distributions of 13 nearby galaxies by means of a physical model which accounts for high-energy proton transport in starburst nuclei and includes the contribution of primary and secondary electrons. In particular, we test the hypothesis that the observed gamma-ray fluxes are mostly due to star-forming activity, in agreement with the available star formation rates coming from IR and UV observations. Through this observation-based approach, we determine the most likely neutrino counterpart from star-forming and starburst galaxies and quantitatively assess the ability of current and upcoming neutrino telescopes to detect them as pointlike sources. Remarkably, we find that the cores of the Small Magellanic Cloud and the Circinus galaxy are potentially observable by KM3NeT/ARCA with 6 yr of observation. Moreover, most of the nearby galaxies are likely to be just a factor of a few below the KM3NeT and IceCube-Gen2 pointlike sensitivities. After investigating the prospects for detection of gamma-rays above TeV energies from these sources, we conclude that the joint observations of high-energy neutrinos and gamma-rays with upcoming telescopes will be an objective test for our emission model and may provide compelling evidence of star-forming activity as a tracer of neutrino production.
We discuss in detail the evolutionary properties of low-mass stars (M < 1 M sub(o)) having metallicity lower than Z = 10 super(-6) from the pre-main sequence up to (almost) the end of the early ...asymptotic giant branch phase. We also discuss the possibility that the large C/Fe, N/Fe observed on the surface of the most iron-poor star currently known, HE 0107-5240, could be attributed to the autopollution induced by the penetration of the He convective shell into the H-rich mantle during the He core flash of a low-mass, very low metallicity star. On the basis of a quite detailed analysis, we conclude that the autopollution scenario cannot be responsible for the observed chemical composition of HE 0107-5240.
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The static spherically symmetric traversable wormholes are analysed in the Einstein-Cartan theory of gravitation. In particular, we computed the torsion tensor for matter fields with different spin
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. Interestingly, only for certain values of the spin, the torsion contribution to the Einstein-Cartan field equation allows one to satisfy both flaring-out condition and null energy condition. In this scenario, traversable wormholes can be produced by using usual (non-exotic) spinning matter.
Colorectal cancer is mainly attributed to diet, but the role exerted by foods remains unclear because involved factors are extremely complex. Geography substantially impacts on foods. Correlations ...between international variation in colorectal cancer-associated mutation patterns and food availabilities could highlight the influence of foods on colorectal mutagenesis.
To test such hypothesis, we applied techniques based on hierarchical clustering, feature extraction and selection, and statistical pattern recognition to the analysis of 2,572 colorectal cancer-associated TP53 mutations from 12 countries/geographic areas. For food availabilities, we relied on data extracted from the Food Balance Sheets of the Food and Agriculture Organization of the United Nations. Dendrograms for mutation sites, mutation types and food patterns were constructed through Ward's hierarchical clustering algorithm and their stability was assessed evaluating silhouette values. Feature selection used entropy-based measures for similarity between clusterings, combined with principal component analysis by exhaustive and heuristic approaches.
Mutations clustered in two major geographic groups, one including only Western countries, the other Asia and parts of Europe. This was determined by variation in the frequency of transitions at CpGs, the most common mutation type. Higher frequencies of transitions at CpGs in the cluster that included only Western countries mainly reflected higher frequencies of mutations at CpG codons 175, 248 and 273, the three major TP53 hotspots. Pearson's correlation scores, computed between the principal components of the datamatrices for mutation types, food availability and mutation sites, demonstrated statistically significant correlations between transitions at CpGs and both mutation sites and availabilities of meat, milk, sweeteners and animal fats, the energy-dense foods at the basis of "Western" diets. This is best explainable by differential exposure to nitrosative DNA damage due to foods that promote metabolic stress and chronic inflammation.
CpG sites in an individual molecule may exist in a binary state (methylated or unmethylated) and each individual DNA molecule, containing a certain number of CpGs, is a combination of these states ...defining an epihaplotype. Classic quantification based approaches to study DNA methylation are intrinsically unable to fully represent the complexity of the underlying methylation substrate. Epihaplotype based approaches, on the other hand, allow methylation profiles of cell populations to be studied at the single molecule level. For such investigations, next-generation sequencing techniques can be used, both for quantitative and for epihaplotype analysis. Currently available tools for methylation analysis lack output formats that explicitly report CpG methylation profiles at the single molecule level and that have suited statistical tools for their interpretation.
Here we present ampliMethProfiler, a python-based pipeline for the extraction and statistical epihaplotype analysis of amplicons from targeted deep bisulfite sequencing of multiple DNA regions.
ampliMethProfiler tool provides an easy and user friendly way to extract and analyze the epihaplotype composition of reads from targeted bisulfite sequencing experiments. ampliMethProfiler is written in python language and requires a local installation of BLAST and (optionally) QIIME tools. It can be run on Linux and OS X platforms. The software is open source and freely available at http://amplimethprofiler.sourceforge.net .
Abstract
Considering the high star formation rate (up to 100 M
⊙
/year) of starburst galaxies (SBGs), they are well posed between the guaranteed “factories” of high energy neutrinos, since they can ...contain accelerated cosmic rays in the central region where the high-density gas is present. A more accurate description of their possible hadronic emission could help to better explain the diffuse astrophysical flux measured by IceCube as well as the observed point-like excess, like the case of NGC1068. With this in mind we report here a multi-messenger study, looking at diffuse and resolved gamma-ray and neutrino measurements, that explain the very-high-energy (VHE) emission through a calorimetric scenario. For the analysis of the diffuse component we perform a blending of the available spectral indexes and produce a multi-component study of extragalactic background light (EGB), high energy starting events (HESE) and high-energy cascade IceCube data. In contrast to common prototype scenarios, the spectral index blending leads to a non negligible diffuse neutrino component from SBGs, accounting up to 40% of the HESE events, at 95.4% CL. This scenario privileges also a maximal energy within tens of PeV for the accelerated charge particles inside these galaxies. For the point-like study we report the proposed calorimetric description for the gamma-ray resolved SBGs within 100 Mpc, taking into account the star formation rate derived from their infrared emission. These neutrino expectations are then compared with the sensitivity of IceCube, IceCube/Gen2 and the incoming KM3NeT.
Star‐forming and starburst galaxies (SBGs), which are well‐known cosmic‐ray (CR) reservoirs, are expected to emit gamma rays and neutrinos predominantly via hadronic collisions. In this work we ...analyze the 10‐year Fermi‐Low Energy Technique (LAT) spectral energy distributions of 13 nearby galaxies by means of a physical model that accounts for high‐energy proton transport in starburst nuclei and includes the contribution of primary and secondary electrons. In particular, we test the hypothesis that the observed gamma‐ray fluxes are mostly due to star‐forming activity, which is in agreement with the available star formation rates coming from infrared (IR) and ultraviolet (UV) observations. Through this observation‐based approach, we determine the most‐likely neutrino counterparts from star‐forming and SBGs and quantitatively assess the ability of current and upcoming neutrino telescopes to detect them as point‐like sources. We also generate mock gamma‐ray data to simulate the Cherenkov Telescope Array (CTA) performance in detecting these sources. Moreover, we propose a test to discriminate between the two different CR transport models for the starburst nuclei by looking at the different gamma‐ray expectations. We point out that current data already gives a slight preference to CR models, which are dominated by advection.
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