Spectral features in galactic cosmic rays

Recent results by space borne experiments took cosmic ray data to a precision level. These new results are able to challenge the conventional scenario for cosmic ray acceleration and propagation in the Milky Way. In these contributions, written for the XVII Vulcano Workshop, we will give an overview of the latest results of the cosmic ray fluxes, and some possible interpretations will be discussed. These measurements have a common feature, namely the presence of unexpected and still not yet fully understood spectral features.Comment: Proceedings of the XVII Vulcano Worksho

Sensitivity of the Cherenkov Telescope Array to TeV photon emission from the Large Magellanic Cloud

A deep survey of the Large Magellanic Cloud at ~0.1-100 TeV photon energies with the Cherenkov Telescope Array is planned. We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters, mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N 157B, N 132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3-2.4 pending a flux increase by a factor of >3-4 over ~2015-2035. Large-scale interstellar emission remains mostly out of reach of the survey if its >10 GeV spectrum has a soft photon index ~2.7, but degree-scale 0.1-10 TeV pion-decay emission could be detected if the cosmic-ray spectrum hardens above >100 GeV. The 30 Doradus star-forming region is detectable if acceleration efficiency is on the order of 1-10 per cent of the mechanical luminosity and diffusion is suppressed by two orders of magnitude withi

It's HIP to be a hub: new trends for old-fashioned proteins

Many endocytic proteins shuttle between the nucleus and the cytoplasm; however, their putative function in the nucleus is unclear. Now, new data demonstrate that huntingtin interacting protein 1 (HIP1), an endocytic protein, modulates the transcriptional activity of nuclear hormone receptors. In network theory, therefore, HIP1 can be regarded as a hub connecting heterogeneous functional “territories:” a possibility with important physiological and pathological implications

Recent results from the ANTARES experiment

ANTARES is currently the largest neutrino telescope operating in the Northern hemisphere. The telescope is designed to search for high-energy neutrinos originating from galactic and extra-galactic sources. The detection principle relies on the observation of Cerenkov light, whose emission is stimulated by the propagation in water of the charged leptons resulting from charged current neutrino interactions in the medium surrounding the detector. The detector is a 3-dimensional array of photomultiplier tubes (PMTs), arranged on twelve vertical lines (each housing 75 PMTs), placed at a depth of about 2500 meters, 40 km off the coast of Toulon, France. The detector was completed in May 2008 and it has been working continuously in its 12-lines configuration for almost one year. The performance and first results will be discussed

Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen

We report the properties of sodium (Na) and aluminum (Al) cosmic rays in the rigidity range 2.15 GV to 3.0 TV based on 0.46 million sodium and 0.51 million aluminum nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. We found that Na and Al, together with nitrogen (N), belong to a distinct cosmic ray group. In this group, we observe that, similar to the N flux, both the Na flux and Al flux are well described by the sums of a primary cosmic ray component (proportional to the silicon flux) and a secondary cosmic ray component (proportional to the fluorine flux). The fraction of the primary component increases with rigidity for the N, Na, and Al fluxes and becomes dominant at the highest rigidities. The Na /Si and Al /Si abundance ratios at the source, 0.036 ±0.003 for Na /Si and 0.103 ±0.004 for Al /Si , are determined independent of cosmic ray propagation

Cosmic-ray ransport parameters and fluorine source abundance from AMS-02 F/Si data

The AMS-02 collaboration recently released cosmic-ray data of unprecedented accuracy for F/Si. In this work, we have studied if this new data can be reproduced by propagation models tuned on lighter secondary-to-primary ratios (Li/C, Be/C, B/C), and how much F at source can be accommodated by the new data, using a 1D diffusion model (USINE code) and performing χ2 analyses accounting for several systematics (energy correlations in data, nuclear cross-sections, and solar modulation uncertainties). The model tuned on Li/C, Be/C, and B/C AMS-02 data overshoots F/Si data by 10-15%. However, this difference can be explained by the 19F production cross-sections uncertainties from a few dominant channels (60% of the produced F comes from the fragmentation of 20Ne, 24Mg, and 28Si). We concluded that all secondary species from Li to F can be explained by the same transport parameters. Additionally, we also draw limits on the F source abundance (relative to Si)

Cosmic-ray ransport parameters and fluorine source abundance from AMS-02 F/Si data

The AMS-02 collaboration recently released cosmic-ray data of unprecedented accuracy for F/Si. In this work, we have studied if this new data can be reproduced by propagation models tuned on lighter secondary-to-primary ratios (Li/C, Be/C, B/C), and how much F at source can be accommodated by the new data, using a 1D diffusion model (USINE code) and performing χ2 analyses accounting for several systematics (energy correlations in data, nuclear cross-sections, and solar modulation uncertainties). The model tuned on Li/C, Be/C, and B/C AMS-02 data overshoots F/Si data by 10-15%. However, this difference can be explained by the 19F production cross-sections uncertainties from a few dominant channels (60% of the produced F comes from the fragmentation of 20Ne, 24Mg, and 28Si). We concluded that all secondary species from Li to F can be explained by the same transport parameters. Additionally, we also draw limits on the F source abundance (relative to Si)

Gluconeogenic Signals Regulate Iron Homeostasis via Hepcidin in Mice.

Hepatic gluconeogenesis provides fuel during starvation, and is abnormally induced in obese individuals or those with diabetes. Common metabolic disorders associated with active gluconeogenesis and insulin resistance (obesity, metabolic syndrome, diabetes, and nonalcoholic fatty liver disease) have been associated with alterations in iron homeostasis that disrupt insulin sensitivity and promote disease progression. We investigated whether gluconeogenic signals directly control Hepcidin, an important regulator of iron homeostasis, in starving mice (a model of persistently activated gluconeogenesis and insulin resistance).|We investigated hepatic regulation of Hepcidin expression in C57BL/6Crl, 129S2/SvPas, BALB/c, and wild-type and Creb3l3-/- null mice. Mice were fed a standard, iron-balanced chow diet or an iron-deficient diet for 9 days before death, or for 7 days before a 24- to 48-hour starvation period; liver and spleen tissues then were collected and analyzed by quantitative reverse-transcription polymerase chain reaction and immunoblot analyses. Serum levels of iron, hemoglobin, Hepcidin, and glucose also were measured. We analyzed human hepatoma (HepG2) cells and mouse primary hepatocytes to study transcriptional control of Hamp (the gene that encodes Hepcidin) in response to gluconeogenic stimuli using small interfering RNA, luciferase promoter, and chromatin immunoprecipitation analyses.|Starvation led to increased transcription of encodes phosphoenolpyruvate carboxykinase 1 (a protein involved in gluconeogenesis) in livers of mice, increased levels of Hepcidin, and degradation of Ferroportin, compared with nonstarved mice. These changes resulted in hypoferremia and iron retention in liver tissue. Livers of starved mice also had increased levels of Ppargc1a messenger RNA and Creb3l3 messenger RNA, which encode a transcriptional co-activator involved in energy metabolism and a liverspecific transcription factor, respectively. Glucagon and a cyclic adenosine monophosphate analog increased promoter activity and transcription of Hamp in cultured liver cells; levels of Hamp were reduced after administration of small interfering RNAs against Ppargc1a and Creb3l3. PPARGC1A and CREB3L3 bound the Hamp promoter to activate its transcription in response to a cyclic adenosine monophosphate analog. Creb3l3-/- mice did not up-regulate Hamp or become hypoferremic during starvation.|We identified a link between glucose and iron homeostasis, showing that Hepcidin is a gluconeogenic sensor in mice during starvation. This response is involved in hepatic metabolic adaptation to increased energy demands; it preserves tissue iron for vital activities during food withdrawal, but can cause excessive iron retention and hypoferremia in disorders with persistently activated gluconeogenesis and insulin resistance