The SED Machine Blagorodnova, Nadejda; Neill, James D.; Walters, Richard ...
Publications of the Astronomical Society of the Pacific,
03/2018, Letnik:
130, Številka:
985
Journal Article
Recenzirano
Current time domain facilities are finding several hundreds of transient astronomical events a year. The discovery rate is expected to increase in the future as soon as new surveys such as the Zwicky ...Transient Facility (ZTF) and the Large Synoptic Sky Survey (LSST) come online. Presently, the rate at which transients are classified is approximately one order or magnitude lower than the discovery rate, leading to an increasing “follow-up drought”. Existing telescopes with moderate aperture can help address this deficit when equipped with spectrographs optimized for spectral classification. Here, we provide an overview of the design, operations and first results of the Spectral Energy Distribution Machine (SEDM), operating on the Palomar 60-inch telescope (P60). The instrument is optimized for classification and high observing efficiency. It combines a low-resolution (R ∼ 100) integral field unit (IFU) spectrograph with “Rainbow Camera” (RC), a multi-band field acquisition camera which also serves as multi-band (ugri) photometer. The SEDM was commissioned during the operation of the intermediate Palomar Transient Factory (iPTF) and has already lived up to its promise. The success of the SEDM demonstrates the value of spectrographs optimized for spectral classification.
iPTF Survey for Cool Transients Adams, S. M.; Blagorodnova, N.; Kasliwal, M. M. ...
Publications of the Astronomical Society of the Pacific,
03/2018, Letnik:
130, Številka:
985
Journal Article
Recenzirano
We performed a wide-area (2000 deg²) g and I band experiment as part of a two month extension to the Intermediate Palomar Transient Factory. We discovered 36 extragalactic transients including ...iPTF17lf, a highly reddened local SN Ia, iPTF17bkj, a new member of the rare class of transitional Ibn/IIn supernovae, and iPTF17be, a candidate luminous blue variable outburst. We do not detect any luminous red novae and place an upper limit on their rate. We show that adding a slow-cadence I band component to upcoming surveys such as the Zwicky Transient Facility will improve the photometric selection of cool and dusty transients.
Low turnover bone (low bone formation rates (BFRs)) with decreased osteoblast number is common in patients with chronic kidney disease (CKD) and attributed to 'over-suppression' of the parathyroid ...hormone (PTH) despite supra-physiologic levels. An alternative hypothesis is abnormal osteoblast differentiation, resulting in low BFRs due to reduced VEGF-A.
We analyzed the expression of VEGF-A and mesenchymal stem cell (MSC) differentiation factors in freshly isolated bone marrow (BM) cells, and in BM cell-derived MSC in rats with different levels of BFRs and PTH (modulated by calcium and zoledronic acid). The regulators of VEGF in MSC were also determined.
VEGF-A expression was reduced in the BM cells from CKD vs. normal animals (p < 0.02). In BM-derived MSC from CKD, there were decreased osteoblast transcription factors and mineralization. In CKD animals, the BM VEGF-A expression was positively correlated with BFR (r = 0.80, p < 0.001). Reducing BFRs in CKD animals led to reductions in VEGF-A expression and osteoblast transcription factors regardless of the PTH level. We therefore examined other regulators of VEGF-A and found decreased expression of hypoxia-inducible factor-1α and the master transcription factor of antioxidants nuclear factor (erythroid-derived 2)-like 2 in CKD animals with low PTH.
Low BFRs in CKD are associated with a basal decrease in VEGF-A expression in BM that may be driven by altered hypoxia and oxidative stress.
Forest structure and dynamics vary across the Amazon Basin in an east-west gradient coincident with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility ...may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. Soil samples were collected in a total of 59 different forest plots across the Amazon Basin and analysed for exchangeable cations, carbon, nitrogen and pH, with several phosphorus fractions of likely different plant availability also quantified. Physical properties were additionally examined and an index of soil physical quality developed. Bivariate relationships of soil and climatic properties with above-ground wood productivity, stand-level tree turnover rates, above-ground wood biomass and wood density were first examined with multivariate regression models then applied. Both forms of analysis were undertaken with and without considerations regarding the underlying spatial structure of the dataset. Despite the presence of autocorrelated spatial structures complicating many analyses, forest structure and dynamics were found to be strongly and quantitatively related to edaphic as well as climatic conditions. Basin-wide differences in stand-level turnover rates are mostly influenced by soil physical properties with variations in rates of coarse wood production mostly related to soil phosphorus status. Total soil P was a better predictor of wood production rates than any of the fractionated organic- or inorganic-P pools. This suggests that it is not only the immediately available P forms, but probably the entire soil phosphorus pool that is interacting with forest growth on longer timescales. A role for soil potassium in modulating Amazon forest dynamics through its effects on stand-level wood density was also detected. Taking this into account, otherwise enigmatic variations in stand-level biomass across the Basin were then accounted for through the interacting effects of soil physical and chemical properties with climate. A hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining endogenous disturbance levels, species composition, and forest productivity across the Amazon Basin.
The International Federation of Accountants (IFAC) has issued a revised "Code of Ethics for Professional Accountants" (IFAC Code). The IFAC Code is intended to be a model code of ethics for national ...accounting organizations throughout the world. Prior research demonstrates that approximately 50% of IFAC member organizations have adopted the IFAC Code as their organizational code of conduct. There is therefore empirical evidence that international convergence of accounting ethical standards is occurring. We employ Hofstede's (2008, http://www. geert-hofstede. com/hofs tede_ dimensions. php) cultural dimensions in an attempt to empirically explain accounting organizations' decisions about whether to adopt the IFAC Code or to retain their organization-specific code. Our results indicate that accounting organizations in cultures with high levels of Individualism and Uncertainty Avoidance are less likely to adopt the model IFAC Code. Organizations in high Individualism and Uncertainty Avoidance societies are therefore less likely to surrender the setting of ethical standards to an outside, international organization.
Recently we reported the presence of specific high affinity binding sites for luteinizing hormone-releasing hormone (LHRH) and its analogues (Kd = 1.5 or 1.7 nM) in the human epithelial ovarian ...cancer cell lines EFO-21 and EFO-27. The proliferation of these cell lines was inhibited by nM concentrations of a LHRH agonist. This study was performed to ascertain whether these ovarian cancer cell lines produce LHRH and whether the high affinity LHRH binding site found previously was identical to the pituitary LHRH receptor. Significant amounts of immunoreactive LHRH were found in the extracts of both the EFO-21 cell line (449 +/- 56 fmol/10(6) cells) and the EFO-27 line (409 +/- 76 fmol/10(6) cells). LHRH bioactivity of these extracts, assessed in terms of release of luteinizing hormone by rat pituitary cells, was comparable to that of authentic LHRH. EFO-21 and EFO-27 cells expressed the mRNAs for both human LHRH and human LHRH receptor as assessed by reverse transcriptase-PCR using oligonucleotide primers according to published sequences. In addition, in eight of eight biopsy samples of human epithelial ovarian cancers we detected mRNA for LHRH, six of these specimens expressed the mRNA representing the LHRH receptor. These data support the concept that human epithelial ovarian cancers might have a local system based on LHRH to regulate cell proliferation. It is still obscure at present whether LHRH produced locally has a stimulatory, inhibitory, or no impact on the proliferation of ovarian cancer cells. However, exogenous LHRH agonists seem to have clear antiproliferative activity, probably mediated through LHRH receptors. This finding might provide the base for novel approaches in the therapy of epithelial ovarian cancer.
This study analyzed 19 naturally mummified pre-Columbian individuals excavated from desert regions of southern Peru and northern Chile. In the majority of autopsies of mummies, the spleen cannot be ...identified due to rapid autolysis and decomposition; therefore, our aim was to identify, in the cases in which the spleen was found, any normal and abnormal structures from mummified spleen tissues. The research consisted of gross and microscopic examinations of the spleen. Pathological features were identified, but no evidence of specific diseases was determined.
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