120 research outputs found
Evolution of Universe to the present inert phase
We assume that current state of the Universe can be described by the Inert
Doublet Model, containing two scalar doublets, one of which is responsible for
EWSB and masses of particles and the second one having no couplings to fermions
and being responsible for dark matter. We consider possible evolutions of the
Universe to this state during cooling down of the Universe after inflation. We
found that in the past Universe could pass through phase states having no DM
candidate. In the evolution via such states in addition to a possible EWSB
phase transition (2-nd order) the Universe sustained one 1-st order phase
transition or two phase transitions of the 2-nd order.Comment: 19 pages, 3 figure
Diffuse coronae in cosmological simulations of milky way-sized galaxies
We investigate the properties of halo gas using three cosmological “zoom-in” simulations of realistic Milky Way-galaxy analogs with varying sub-grid physics. In all three cases, the mass of hot (T > 106 K) halo gas is ˜1% of the host's virial mass. The X-ray luminosity of two of the runs is consistent with observations of the Milky Way, while the third simulation is X-ray bright and resembles more closely a very massive, star-forming spiral. Hot halos extend to 140 kpc from the galactic center and are surrounded by a bubble of warm-hot (T={10}5-{10}6 K) gas that extends to the virial radius. Simulated halos agree well outside 20-30 kpc with the β-model of Miller & Bregman based on O vii absorption and O viii emission measurements. Warm-hot and hot gas contribute up to 80% of the total gas reservoir, and contain nearly the same amount of baryons as the stellar component. The mass of warm-hot and hot components falls into the range estimated for {L}* galaxies. With key observational constraints on the density of the Milky Way corona being satisfied, we show that concealing of the ubiquitous warm-hot baryons, along with the ejection of just 20%-30% of the diffuse gas out of the potential wells by supernova-driven outflows, can solve the “missing baryon problem.” The recovered baryon fraction within 3 virial radii is 90% of the universal value. With a characteristic density of ˜10-4 cm-3 at 50-80 kpc, diffuse coronae meet the requirement for fast and complete ram-pressure stripping of the gas reservoirs in dwarf galaxy satellites
SOME CHARACTERISTICS OF ORGANIC SOILS IRRIGATED WITH MUNICIPAL WASTEWATER
ABSTRACT Soil irrigation with wastewater (WW) gives the opportunity to solve the problems of its disposal, final purification or reuse. Many studies have examined mineral soils upon continued WW application. The aim of this paper was to examine the properties of organic soils 3 years after WW application was discontinued. Peat-muck soil planted with Populus spp. or Salix spp., and mineral-muck soil under grasses were irrigated for 4 years with municipal WW at a low (comparable with intensive NPK fertilization) and high WW rate (600 and 1200 mm yearly, respectively). Soils were analysed for organic matter (OM), pH, bulk density (BD), water holding capacity (WHC), P 2 O 5 , Fe 2 O 3 , Al 2 O 3 , MnO, Zn, Pb, Cu, Cr, magnetic susceptibility (MS) and dehydrogenase and catalase activities. The results were compared with control soils which have never received WW. The study showed that only P 2 O 5 , MnO and catalase activity (CA) were significantly affected by former WW application. On average, P 2 O 5 increased by 30 per cent, whereas MnO decreased by 35 per cent with no differences between the two WW rates. CA decreased by 18 per cent at the high WW rate. Most of tested characteristics were determined by soil type. The peat-muck soil showed higher OM, WHC, P 2 O 5 , MnO, Pb and CA than mineral-muck soil and lower BD, MS, Fe 2 O 3 , Al 2 O 3 and Cr. Soil depth influenced Fe 2 O 3 , MnO, Zn, MS and enzyme activities, while basic soil properties (OM, pH, BD, WHC and P 2 O 5 ) were not changed by soil depth. Heavy metals (Zn, Cr, Cu and Pb) were below upper permissible limits
Orexin receptors exert a neuroprotective effect in Alzheimer's disease (AD) via heterodimerization with GPR103
Orexins are neuropeptides that regulate the sleep-wake cycle and feeding behaviour. QRFP is a newly discovered neuropeptide which exerts similar orexigenic activity, thus playing an important role in energy homeostasis and regulation of appetite. The exact expression and signalling characteristics and physiological actions of QRFP and its receptor GPR103 are poorly understood. Alzheimerâ €™ s disease (AD) patients experience increased nocturnal activity, excessive daytime sleepiness, and weight loss. We hypothesised therefore that orexins and QRFP might be implicated in the pathophysiology of AD. We report that the down-regulation of hippocampal orexin receptors (OXRs) and GPR103 particularly in the cornu ammonis (CA) subfield from AD patients suffering from early onset familial AD (EOFAD) and late onset familial AD (LOAD). Using an in vitro model we demonstrate that this downregulation is due to to Aβ-plaque formation and tau hyper-phosphorylation. Transcriptomics revealed a neuroprotective role for both orexins and QRFP. Finally we provide conclusive evidence using BRET and FRET that OXRs and GPR103 form functional hetero-dimers to exert their effects involving activation of ERK 1/2. Pharmacological intervention directed at the orexigenic system may prove to be an attractive avenue towards the discovery of novel therapeutics for diseases such as AD and improving neuroprotective signalling pathways
The Baryonic Collapse Efficiency of Galaxy Groups in the RESOLVE and ECO Surveys
We examine the z = 0 group-integrated stellar and cold baryonic (stars + cold atomic gas) mass functions (group SMF and CBMF) and the baryonic collapse efficiency (group cold baryonic to dark matter halo mass ratio) using the RESOLVE and ECO survey galaxy group catalogs and a galform semi-analytic model (SAM) mock catalog. The group SMF and CBMF fall off more steeply at high masses and rise with a shallower low-mass slope than the theoretical halo mass function (HMF). The transition occurs at group-integrated cold baryonic mass M_coldbary ~ 10^11 Msun. The SAM, however, has significantly fewer groups at the transition mass ~ 10^11 Msun and a steeper low-mass slope than the data, suggesting that feedback is too weak in low-mass halos and conversely too strong near the transition mass. Using literature prescriptions to include hot halo gas and potential unobservable galaxy gas produces a group BMF with slope similar to the HMF even below the transition mass. Its normalization is lower by a factor of ~2, in agreement with estimates of warm-hot gas making up the remaining difference. We compute baryonic collapse efficiency with the halo mass calculated two ways, via halo abundance matching (HAM) and via dynamics (extended all the way to three-galaxy groups using stacking). Using HAM, we find that baryonic collapse efficiencies reach a flat maximum for groups across the halo mass range of M_halo ~ 10^11.4-12 Msun, which we label "nascent groups." Using dynamics, however, we find greater scatter in baryonic collapse efficiencies, likely indicating variation in group hot-to-cold baryon ratios. Similarly, we see higher scatter in baryonic collapse efficiencies in the SAM when using its true groups and their group halo masses as opposed to friends-of-friends groups and HAM masses
Angular Momentum of Early- and Late-type Galaxies: Nature or Nurture?
We investigate the origin, the shape, the scatter, and the cosmic evolution
in the observed relationship between specific angular momentum and
the stellar mass in early-type (ETGs) and late-type galaxies (LTGs).
Specifically, we exploit the observed star-formation efficiency and chemical
abundance to infer the fraction f_\rm inf of baryons that infall toward the
central regions of galaxies where star formation can occur. We find f_\rm
inf\approx 1 for LTGs and for ETGs with an uncertainty of about
dex, consistent with a biased collapse. By comparing with the locally
observed vs. relations for LTGs and ETGs we estimate the
fraction of the initial specific angular momentum associated to the
infalling gas that is retained in the stellar component: for LTGs we find
, in line with the classic disc formation
picture; for ETGs we infer , that can be
traced back to a evolution via dry mergers. We also show that the
observed scatter in the vs. relation for both galaxy
types is mainly contributed by the intrinsic dispersion in the spin parameters
of the host dark matter halo. The biased collapse plus mergers scenario implies
that the specific angular momentum in the stellar components of ETG progenitors
at is already close to the local values, in pleasing agreement with
observations. All in all, we argue such a behavior to be imprinted by nature
and not nurtured substantially by the environment
The CLIC Potential for New Physics
The Compact Linear Collider (CLIC) is a mature option for the future of high
energy physics. It combines the benefits of the clean environment of
colliders with operation at high centre-of-mass energies, allowing to probe
scales beyond the reach of the Large Hadron Collider (LHC) for many scenarios of new physics. This places the CLIC project at a privileged spot in between the precision and energy frontiers, with capabilities that will significantly extend knowledge on both fronts at the end of the LHC era. In this report we review and revisit the potential of CLIC to search, directly and indirectly, for physics beyond the Standard Model
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