Galaxy Clusters as Reservoirs of Heavy Dark Matter and High-Energy Cosmic Rays: Constraints from Neutrino Observations

Galaxy Clusters (GCs) are the largest reservoirs of both dark matter and cosmic rays (CRs). Dark matter self-annihilation can lead to a high luminosity in gamma rays and neutrinos, enhanced by a strong degree of clustering in dark matter substructures. Hadronic CR interactions can also lead to a high luminosity in gamma rays and neutrinos, enhanced by the confinement of CRs from cluster accretion/merger shocks and active galactic nuclei. We show that IceCube/KM3Net observations of high-energy neutrinos can probe the nature of GCs and the separate dark matter and CR emission processes, taking into account how the results depend on the still-substantial uncertainties. Neutrino observations are relevant at high energies, especially at >10 TeV. Our results should be useful for improving experimental searches for high-energy neutrino emission. Neutrino telescopes are sensitive to extended sources formed by dark matter substructures and CRs distributed over large scales. Recent observations by Fermi and imaging atmospheric Cherenkov telescopes have placed interesting constraints on the gamma-ray emission from GCs. We also provide calculations of the gamma-ray fluxes, taking into account electromagnetic cascades inside GCs, which can be important for injections at sufficiently high energies. This also allows us to extend previous gamma-ray constraints to very high dark matter masses and significant CR injections at very high energies. Using both neutrinos and gamma rays, which can lead to comparable constraints, will allow more complete understandings of GCs. Neutrinos are essential for some dark matter annihilation channels, and for hadronic instead of electronic CRs. Our results suggest that the multi-messenger observations of GCs will be able to give useful constraints on specific models of dark matter and CRs. [Abstract abridged.]Comment: 31 pages, 20 figures, 1 table, accepted for publication in JCAP, references and discussions adde

Electron and hole transmission through superconductor - normal metal interfaces

We have investigated the transmission of electrons and holes through interfaces between superconducting aluminum (Tc = 1.2 K) and various normal non-magnetic metals (copper, gold, palladium, platinum, and silver) using Andreev-reflection spectroscopy at T = 0.1 K. We analyzed the point contacts with the modified BTK theory that includes Dynes' lifetime as a fitting parameter G in addition to superconducting energy gap 2D and normal reflection described by Z. For contact areas from 1 nm^2 to 10000 nm^2 the BTK Z parameter was 0.5, corresponding to transmission coefficients of about 80 %, independent of the normal metal. The very small variation of Z indicates that the interfaces have a negligible dielectric tunneling barrier. Fermi surface mismatch does not account for the observed transmission coefficient.Comment: 9 pages, 4 figures, submitted to Proceedings of the 19th International Conference on Magnetism ICM2012 (Busan 2012

Propagation of ultrahigh energy nuclei in clusters of galaxies: resulting composition and secondary emissions

We study the survival of ultrahigh energy nuclei injected in clusters of galaxies, as well as their secondary neutrino and photon emissions, using a complete numerical propagation method and a realistic modeling of the magnetic, baryonic and photonic backgrounds. It is found that the survival of heavy nuclei highly depends on the injection position and on the profile of the magnetic field. Taking into account the limited lifetime of the central source could also lead in some cases to the detection of a cosmic ray afterglow, temporally decorrelated from neutrino and gamma ray emissions. We calculate that the diffusive neutrino flux around 1 PeV coming from clusters of galaxies may have a chance to be detected by current instruments. The observation of single sources in neutrinos and in gamma rays produced by ultrahigh energy cosmic rays will be more difficult. Signals coming from lower energy cosmic rays (E < 1 PeV), if they exist, might however be detected by Fermi, for reasonable sets of parameters.Comment: 19 pages, 15 figures, version to appear in ApJ (minor changes

Intercomparison of the northern hemisphere winter mid-latitude atmospheric variability of the IPCC models

We compare, for the overlapping time frame 1962-2000, the estimate of the northern hemisphere (NH) mid-latitude winter atmospheric variability within the XX century simulations of 17 global climate models (GCMs) included in the IPCC-4AR with the NCEP and ECMWF reanalyses. We compute the Hayashi spectra of the 500hPa geopotential height fields and introduce an integral measure of the variability observed in the NH on different spectral sub-domains. Only two high-resolution GCMs have a good agreement with reanalyses. Large biases, in most cases larger than 20%, are found between the wave climatologies of most GCMs and the reanalyses, with a relative span of around 50%. The travelling baroclinic waves are usually overestimated, while the planetary waves are usually underestimated, in agreement with previous studies performed on global weather forecasting models. When comparing the results of various versions of similar GCMs, it is clear that in some cases the vertical resolution of the atmosphere and, somewhat unexpectedly, of the adopted ocean model seem to be critical in determining the agreement with the reanalyses. The GCMs ensemble is biased with respect to the reanalyses but is comparable to the best 5 GCMs. This study suggests serious caveats with respect to the ability of most of the presently available GCMs in representing the statistics of the global scale atmospheric dynamics of the present climate and, a fortiori, in the perspective of modelling climate change.Comment: 39 pages, 8 figures, 2 table

Оцінка різних методів контролю якості зернової сировини

The article highlights the need of the control of the quality of grain raw materials, because the increasing of the competitiveness of the grain industry is one of the leading in the national agrarian economy of Ukraine and largely its determines the place in the global agrarian market. In competition, only those enterprises retain and improve their position in the market, which consistently work to support and improve the quality of the products according to the important indicators for consumers. The main indicators of the grain quality are: protein content, and also humidity, smell, impurities, crude fat, ash content, etc. Todays, domestic enterprises introduce into the manufacturing the unique scientific and technical developments, which allow quickly and qualitatively conduct the research of raw materials and finished products. However, sometimes when controlling grain raw materials on such enterprises where the modern (spectrometric) research methods are used, some physico-chemical parameters do not coincide with the normative (arbitration) research methods. Therefore, in a comparative aspect were investigated samples of soybean, corn, barley and rapeseed by some qualitative indicators, such as humidity, crude protein and fat. By comparing two methods, it was found out that in the soybean and corn samples, both the arbitrage and the spectrometric methods were almost identical. In some rapeseed and barley samples, the difference between the same samples was small and was not more than 4.8 %. In determining the crude protein in the same samples in soybeans, the difference was from 0.9 to 5.1 %, corn grains – 2.6–5.6 %, barley grains – 0.9 to 5.8 %, rapeseed – 1.4–9.8 %. In determining the fat content of identical samples in soybeans, the difference was small and ranged from 3.8–6.2 %, corn grains 2.6–4.8 %, barley grains – 4.2–6.4 %, seeds rapeseed – 7.1–11.6 %. In the conducted interlaboratory researchers, in determining moisture, crude protein and fat in grain and oil raw materials, by both arbitration and spectrometric methods it was found out, that the results of the studies were within the statistically probable error, which indicate on the high efficiency the last one. In addition, the values of qualitative indicators of the researches samples responses the requirements of regulatory documents.У статті висвітлено необхідність контролю якості зернової сировини, оскільки підвищення конкурентоспроможності зернової галузі є однією із провідних у національній аграрній економіці України та значною мірою визначає її місце на світовому аграрному ринку. У конкурентній боротьбі лише ті підприємства зберігають і поліпшують своє становище на ринку, які послідовно ведуть роботу з підтримання і вдосконалення якості продукції за важливими для споживачів показниками. Основними показниками якості зерна є вміст у ньому білка, а також вологість, запах, домішки, сирий жир, зольність тощо. Сьогодні на вітчизняних підприємствах впроваджують у виробництво унікальні науково-технічні розробки, які дозволяють швидко та якісно проводити дослідження сировини та готової продукції. Однак інколи при контролюванні зернової сировини на таких підприємствах, де використовують сучасні (спектрометричні) методи досліджень, деякі фізико-хімічні показники не збігаються з нормативними (арбітражними) методами досліджень. Тому в порівняльному аспекті досліджували зразки сої, кукурудзи, ячменю та ріпаку за деякими якісними показниками, а саме вологістю, сирим протеїном та жиром. При порівнянні двох методів було встановлено, що у зразках сої та кукурудзи як арбітражним, так і спектрометричним методами результати досліджень майже збігалися. В окремих зразках ріпаку та ячменю різниця між однаковими зразками була невеликою і становила не більше ніж 4,8 %. При визначенні сирого протеїну в однакових зразках у бобах сої різниця становила від 0,9 до 5,1 %, зерні кукурудзи – 2,6–5,6 %, зерні ячменю – 0,9 до 5,8 %, насінні ріпаку – 1,4–9,8 %. При визначенні вмісту жиру в однакових зразках у бобах сої різниця була невелика і коливалася в межах 3,8–6,2 %, зерні кукурудзи 2,6–4,8 %, зерні ячменю – 4,2–6,4 %, насінні ріпаку – 7,1–11,6 %. При проведенні міжлабораторних випробувань при визначенні вологості, сирого протеїну та жиру в зерновій та олійній сировині як арбітражними, так і спектрометричним методами було встановлено, що результати досліджень перебували в межах статистично вірогідної похибки, що вказує на високу ефективність останнього. Окрім того, значення якісних показників дослідних зразків відповідали вимогам нормативних документів

The rice mitochondrial iron transporter is essential for plant growth

In plants, iron (Fe) is essential for mitochondrial electron transport, heme, and Fe-Sulphur (Fe-S) cluster synthesis; however, plant mitochondrial Fe transporters have not been identified. Here we show, identify and characterize the rice mitochondrial Fe transporter (MIT). Based on a transfer DNA library screen, we identified a rice line showing symptoms of Fe deficiency while accumulating high shoot levels of Fe. Homozygous knockout of MIT in this line resulted in a lethal phenotype. MIT localized to the mitochondria and complemented the growth of Δmrs3Δmrs4 yeast defective in mitochondrial Fe transport. The growth of MIT-knockdown (mit-2) plants was also significantly impaired despite abundant Fe accumulation. Further, the decrease in the activity of the mitochondrial and cytosolic Fe-S enzyme, aconitase, indicated that Fe-S cluster synthesis is affected in mit-2 plants. These results indicate that MIT is a mitochondrial Fe transporter essential for rice growth and development

GPR80/99, proposed to be the P2Y15 receptor activated by adenosine and AMP, is not a P2Y receptor

The orphan receptor GPR80 (also called GPR99) was recently reported to be the P2Y15 receptor activated by AMP and adenosine and coupled to increases in cyclic AMP accumulation and intracellular Ca2+ mobilization (Inbe et al. J Biol Chem 2004; 279: 19790–9[12]). However, the cell line (HEK293) used to carry out those studies endogenously expresses A2A and A2B adenosine receptors as well as multiple P2Y receptors, which complicates the analysis of a potential P2Y receptor. To determine unambiguously whether GPR80 is a P2Y receptor subtype, HA-tagged GPR80 was either stably expressed in CHO cells or transiently expressed in COS-7 and HEK293 cells, and cell surface expression was verified by radioimmunoassay (RIA). COS-7 cells overexpressing GPR80 showed a consistent twofold increase in basal inositol phosphate accumulation. However, neither adenosine nor AMP was capable of promoting accumulation of either cyclic AMP or inositol phosphates in any of the three GPR80-expressing cells. A recent paper (He et al. Nature 2004; 429: 188–93 [15]) reported that GPR80 is a Gq-coupled receptor activated by the citric acid cycle intermediate, α-ketoglutarate. Consistent with this report, α-ketoglutarate promoted inositol phosphate accumulation in CHO and HEK293 cells expressing GPR80, and pretreatment of GPR80-expressing COS-7 cells with glutamate dehydrogenase, which converts α-ketoglutarate to glutamate, decreased basal levels of inositol phosphates. Taken together, these data demonstrate that GPR80 is not activated by adenosine, AMP or other nucleotides, but instead is activated by α-ketoglutarate. Therefore, GPR80 is not a new member of the P2Y receptor family

Atlantic Ocean influence on a shift in European climate in the 1990s

European climate exhibits variability on a wide range of timescales. Understanding the nature and drivers of this variability is an essential step in developing robust climate predictions and risk assessments. The Atlantic Ocean has been suggested as an important driver of variability in European climate on decadal timescales1, but the importance of this influence in recent decades has been unclear, partly because of difficulties in separating the influence of the Atlantic Ocean from other contributions, for example, from the tropical Pacific Ocean and the stratosphere. Here we analyse four data sets derived from observations to show that, during the 1990s, there was a substantial shift in European climate towards a pattern characterized by anomalously wet summers in northern Europe, and hot, dry, summers in southern Europe, with related shifts in spring and autumn. These changes in climate coincided with a substantial warming of the North Atlantic Ocean, towards a state last seen in the 1950s. The patterns of European climate change in the 1990s are consistent with earlier changes attributed to the influence of the North Atlantic Ocean, and provide compelling evidence that the Atlantic Ocean was the key driver. Our results suggest that the recent pattern of anomalies in European climate will persist as long as the North Atlantic Ocean remains anomalously warm

A verification framework for interannual-to-decadal predictions experiments

Decadal predictions have a high profile in the climate science community and beyond, yet very little is known about their skill. Nor is there any agreed protocol for estimating their skill. This paper proposes a sound and coordinated framework for verification of decadal hindcast experiments. The framework is illustrated for decadal hindcasts tailored to meet the requirements and specifications of CMIP5 (Coupled Model Intercomparison Project phase 5). The chosen metrics address key questions about the information content in initialized decadal hindcasts. These questions are: (1) Do the initial conditions in the hindcasts lead to more accurate predictions of the climate, compared to un-initialized climate change projections? and (2) Is the prediction model’s ensemble spread an appropriate representation of forecast uncertainty on average? The first question is addressed through deterministic metrics that compare the initialized and uninitialized hindcasts. The second question is addressed through a probabilistic metric applied to the initialized hindcasts and comparing different ways to ascribe forecast uncertainty. Verification is advocated at smoothed regional scales that can illuminate broad areas of predictability, as well as at the grid scale, since many users of the decadal prediction experiments who feed the climate data into applications or decision models will use the data at grid scale, or downscale it to even higher resolution. An overall statement on skill of CMIP5 decadal hindcasts is not the aim of this paper. The results presented are only illustrative of the framework, which would enable such studies. However, broad conclusions that are beginning to emerge from the CMIP5 results include (1) Most predictability at the interannual-to-decadal scale, relative to climatological averages, comes from external forcing, particularly for temperature; (2) though moderate, additional skill is added by the initial conditions over what is imparted by external forcing alone; however, the impact of initialization may result in overall worse predictions in some regions than provided by uninitialized climate change projections; (3) limited hindcast records and the dearth of climate-quality observational data impede our ability to quantify expected skill as well as model biases; and (4) as is common to seasonal-to-interannual model predictions, the spread of the ensemble members is not necessarily a good representation of forecast uncertainty. The authors recommend that this framework be adopted to serve as a starting point to compare prediction quality across prediction systems. The framework can provide a baseline against which future improvements can be quantified. The framework also provides guidance on the use of these model predictions, which differ in fundamental ways from the climate change projections that much of the community has become familiar with, including adjustment of mean and conditional biases, and consideration of how to best approach forecast uncertainty