We present the results of the spectroscopic and photometric monitoring campaign of ASASSN-15ed. The transient was discovered quite young by the All Sky Automated Survey for SuperNovae (ASAS-SN) ...survey. Amateur astronomers allowed us to sample the photometric SN evolution around maximum light, which we estimate to have occurred on JD = 2457087.4 ± 0.6 in the r band. Its apparent r-band magnitude at maximum was r = 16.91 ± 0.10, providing an absolute magnitude M
r
≈ −20.04 ± 0.20, which is slightly more luminous than the typical magnitudes estimated for Type Ibn SNe. The post-peak evolution was well monitored, and the decline rate (being in most bands around 0.1 mag d−1 during the first 25 d after maximum) is marginally slower than the average decline rates of SNe Ibn during the same time interval. The object was initially classified as a Type Ibn SN because early-time spectra were characterized by a blue continuum with superimposed narrow P-Cygni lines of He i, suggesting the presence of a slowly moving (1200–1500 km s−1), He-rich circumstellar medium. Later on, broad P-Cygni He i lines became prominent. The inferred velocities, as measured from the minimum of the broad absorption components, were between 6000 and 7000 km s−1. As we attribute these broad features to the SN ejecta, this is the first time we have observed the transition of a Type Ibn SN to a Type Ib SN.
iClostridium difficile/i infections become a serious problem in terms of nosocomial infections, as well as a consequence of common use of antibiotics.
The aim of the study was to evaluate ...iClostridium difficile/i carriage in patients admitted to the Clinical Department of Infectious Diseases and Hepatology without acute or chronic diarrhea and to assess the impact of antibiotic treatment on the development of enteritis in hospital. Other factors that may affect the risk of infection were also analyzed.
Fourteen patients (14%) were carriers of iClostridium difficile/i at admission. Second assessment taken after fourteen days of antibiotic treatment showed decrease in GDH antigen prevalence to eight subjects (12.1%). Three patients (3%) had diarrhea during hospitalization, and the toxins A and/or B were found in them.
The frequency of iClostridium difficile/i carriage among adults in Poland may be underestimated. Screening for Clostridium difficile GDH antigen may be useful although do not provide definite prognosis of symptomatic disease during ceftriaxone treatment. The risk of Clostridium difficile infection may be reduced mainly by rationalizing antibiotic therapy and following appropriate procedures.
We present the first definitive measurement of the absolute magnitude of RR Lyrae c-type variable stars (RRc) determined purely from statistical parallax. We use a sample of 242 RRc variables ...selected from the All Sky Automated Survey for which high-quality light curves, photometry, and proper motions are available. We obtain high-resolution echelle spectra for these objects to determine radial velocities and abundances as part of the Carnegie RR Lyrae Survey. We find that MV, RRc = 0.59 + or - 0.10 at a mean metallicity of Fe/H = -1.59. This is to be compared with previous estimates for RRab stars (MV, RRab = 0.76 + or - 0.12) and the only direct measurement of an RRc absolute magnitude (RZ Cephei, MV, RRc = 0.27 + or - 0.17). We find the bulk velocity of the halo relative to the Sun to be (W sub(pi), W sub(theta), W sub(z)) = (12.0, -209.9, 3.0) km s super(-1) in the radial, rotational, and vertical directions with dispersions ( super(sigma)W sub(pi), super(sigma)W sub(theta), super(sigma)Wz) = (150.4, 106.1, 96.0) km s super(-1). For the disk, we find (W sub(pi), W sub(theta), W sub(z)) = (13.0, -42.0, -27.3) km s super(-1) relative to the Sun with dispersions ( super(sigma)W sub(pi), super(sigma)W sub(theta), super(sigma)Wz) = (67.7, 59.2, 54.9) km s super(-1). Finally, as a byproduct of our statistical framework, we are able to demonstrate that UCAC2 proper-motion errors are significantly overestimated as verified by UCAC4.
The Vertically Integrated Photon Imaging Chip (VIPIC) project explores opportunities of the three-dimensional integration for imaging of X-rays. The design details of the VIPIC1 chip are presented ...and are followed by results of testing of the chip. The VIPIC1 chip was designed in a 130 nm process, in which through silicon vias are embedded right after the front-end-of-line processing. The integration of tiers is achieved by the Cu-Cu thermo-compression or Cu-based oxide-oxide bonding. The VIPIC1 readout integrated circuit was designed for high timing resolution, pixel based, X-ray Photon Correlation Spectroscopy experiments typically using 8 keV X-rays at a synchrotron radiation facility. The design was done for bonding a Silicon pixel detector, however other materials can be serviced as long as the positive polarity of charge currents is respected.
•The K3Nd(PO4)2 powders built of nanometric sized crystals have been obtained.•The polymorphic transition β/α depends strongly on preparation method.•The activation energy of active dipoles in ...K3Nd(PO4)2 has been determined.
The binary neodymium–potassium phosphate β-K3Nd(PO4)2 was obtained by the ceramic and modified Pechini methods. The obtained powders were studied using TGA/DSC, XRD, FTIR and BET techniques. The materials obtained by the Pechini method show a strong tendency towards agglomeration. The average crystallite size of β-K3Nd(PO4)2 obtained at 480°C amounts to about 30nm.
The temperature and enthalpy of the β/α-K3Nd(PO4)2 polymorphic transition were determined. In the case of the materials obtained by the Pechini method, the polymorphic transition occurs at 1181°C and it is assisted by one endothermic effect with the ΔHph.tr.=58±9kJmol−1. For powders obtained by ceramic technique the β/α polymorphic transition takes place in a temperature range of 1148–1180°C and is accompanied by two endothermic effects with the total enthalpy change of 53±15kJmol−1. The effect of the synthesis method and that of the size of the phosphate crystallites on the mechanism of polymorphic transition have been discussed.
The electric permittivity and dielectric loss measurements were carried out, too. The activation energy of active dipoles in K3Nd(PO4)2 was determined on the basis of the electric permittivity and the dielectric dispersion and absorption measurements. The activation energy amounts to 149.8kJmol−1.
ASASSN-15lh: A highly super-luminous supernova Dong, Subo; Shappee, B. J.; Prieto, J. L. ...
Science (American Association for the Advancement of Science),
01/2016, Letnik:
351, Številka:
6270
Journal Article
Recenzirano
Odprti dostop
Here, we report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu,AB = ...–23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 1045 ergs s–1, which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ –25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 1052 ergs, challenging the magnetar model for its engine.
Skeletal muscle mass and strength diminish during periods of disuse but recover upon return to weight bearing in healthy adults but are incomplete in old muscle. Efforts to improve muscle recovery in ...older individuals commonly aim at increasing myofibrillar protein synthesis via mammalian target of rapamycin (mTOR) stimulation despite evidence demonstrating that old muscle has chronically elevated levels of mammalian target of rapamycin complex 1 (mTORC1) activity. We hypothesized that protein synthesis is higher in old muscle than adult muscle, which contributes to a proteostatic stress that impairs recovery.
We unloaded hindlimbs of adult (10-month) and old (28-month) F344BN rats for 14 days to induce atrophy, followed by reloading up to 60 days with deuterium oxide (D
O) labelling to study muscle regrowth and proteostasis.
We found that old muscle has limited recovery of muscle mass during reloading despite having higher translational capacity and myofibrillar protein synthesis (0.029 k/day ± 0.002 vs. 0.039 k/day ± 0.002, P < 0.0001) than adult muscle. We showed that collagen protein synthesis was not different (0.005 k (1/day) ± 0.0005 vs. 0.004 k (1/day) ± 0.0005, P = 0.15) in old compared to adult, but old muscle had higher collagen concentration (4.5 μg/mg ± 1.2 vs. 9.8 μg/mg ± 0.96, P < 0.01), implying that collagen breakdown was slower in old muscle than adult muscle. This finding was supported by old muscle having more insoluble collagen (4.0 ± 1.1 vs. 9.2 ± 0.9, P < 0.01) and an accumulation of advanced glycation end products (1.0 ± 0.06 vs. 1.5 ± 0.08, P < 0.001) than adult muscle during reloading. Limited recovery of muscle mass during reloading is in part due to higher protein degradation (0.017 1/t ± 0.002 vs. 0.028 1/t ± 0.004, P < 0.05) and/or compromised proteostasis as evidenced by accumulation of ubiquitinated insoluble proteins (1.02 ± 0.06 vs. 1.22 ± 0.06, P < 0.05). Last, we showed that synthesis of individual proteins related to protein folding/refolding, protein degradation and neural-related biological processes was higher in old muscle during reloading than adult muscle.
Our data suggest that the failure of old muscle to recover after disuse is not due to limitations in the ability to synthesize myofibrillar proteins but because of other impaired proteostatic mechanisms (e.g., protein folding and degradation). These data provide novel information on individual proteins that accumulate in protein aggregates after disuse and certain biological processes such as protein folding and degradation that likely play a role in impaired recovery. Therefore, interventions to enhance regrowth of old muscle after disuse should be directed towards the identified impaired proteostatic mechanisms and not aimed at increasing protein synthesis.
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