6,874 research outputs found
Monte Carlo Method for Calculating Oxygen Abundances and Their Uncertainties from Strong-Line Flux Measurements
We present the open-source Python code pyMCZ that determines oxygen abundance
and its distribution from strong emission lines in the standard metallicity
calibrators, based on the original IDL code of Kewley & Dopita (2002) with
updates from Kewley & Ellison (2008), and expanded to include more recently
developed calibrators. The standard strong-line diagnostics have been used to
estimate the oxygen abundance in the interstellar medium through various
emission line ratios in many areas of astrophysics, including galaxy evolution
and supernova host galaxy studies. We introduce a Python implementation of
these methods that, through Monte Carlo sampling, better characterizes the
statistical oxygen abundance confidence region including the effect due to the
propagation of observational uncertainties. These uncertainties are likely to
dominate the error budget in the case of distant galaxies, hosts of cosmic
explosions. Given line flux measurements and their uncertainties, our code
produces synthetic distributions for the oxygen abundance in up to 15
metallicity calibrators simultaneously, as well as for E(B-V), and estimates
their median values and their 68% confidence regions. We test our code on
emission line measurements from a sample of nearby supernova host galaxies (z <
0.15) and compare our metallicity results with those from previous methods. Our
metallicity estimates are consistent with previous methods but yield smaller
statistical uncertainties. Systematic uncertainties are not taken into account.
We offer visualization tools to assess the spread of the oxygen abundance in
the different calibrators, as well as the shape of the estimated oxygen
abundance distribution in each calibrator, and develop robust metrics for
determining the appropriate Monte Carlo sample size. The code is open access
and open source and can be found at https://github.com/nyusngroup/pyMCZ
(Abridged)Comment: Accepted for publication in Astronomy& Computing, 2016. The code is
open-access, open-source, and suggestions and improvements are welcome! The
python module is available at https://github.com/nyusngroup/pyMC
Urinary excretion of RAS, BMP, and WNT pathway components in diabetic kidney disease.
Abstract The renin-angiotensin system (RAS), bone morphogenetic protein (BMP), and WNT pathways are involved in pathogenesis of diabetic kidney disease (DKD). This study characterized assays for urinary angiotensinogen (AGT), gremlin-1, and matrix metalloproteinase 7 (MMP-7), components of the RAS, BMP, and WNT pathways and examined their excretion in DKD. We measured urine AGT, gremlin-1, and MMP-7 in individuals with type 1 diabetes and prevalent DKD (n = 20) or longstanding (n = 61) or new-onset (n = 10) type 1 diabetes without DKD. These urine proteins were also quantified in type 2 DKD (n = 11) before and after treatment with candesartan. The utilized immunoassays had comparable inter- and intra-assay and intraindividual variation to assays used for urine albumin. Median (IQR) urine AGT concentrations were 226.0 (82.1, 550.3) and 13.0 (7.8, 20.0) μg/g creatinine in type 1 diabetes with and without DKD, respectively (P < 0.001). Median (IQR) urine gremlin-1 concentrations were 48.6 (14.2, 254.1) and 3.6 (1.7, 5.5) μg/g, respectively (P < 0.001). Median (IQR) urine MMP-7 concentrations were 6.0 (3.8, 10.5) and 1.0 (0.4, 2.9) μg/g creatinine, respectively (P < 0.001). Treatment with candesartan was associated with a reduction in median (IQR) urine AGT/creatinine from 23.5 (1.6, 105.1) to 2.0 (1.4, 13.7) μg/g, which did not reach statistical significance. Urine gremlin-1 and MMP-7 excretion did not decrease with candesartan. In conclusion, DKD is characterized by markedly elevated urine AGT, MMP-7, and gremlin-1. AGT decreased in response to RAS inhibition, suggesting that this marker reflects therapeutic response. Urinary components of the RAS, BMP, and WNT pathways may identify risk of DKD and aid development of novel therapeutics
Study Fishing Ground In Kampar Kiri River Gunung Sahilan Village, Gunung Sahilan District, Kampar Regency, Province Of Riau
This study was conducted in May 2015 during the dry season in Kampar Kiri river Gunung Sahilan village, Gunung Sahilan district, Kampar regency, province of Riau. Purpose of this study was to obtain data on environmental parameters become the benchmark fishing grounds and fishing activity. Environmental parameters measured are temperature, current speed, brightness, depth, acidity (pH) and dissolved oxygen. After doing this research is that the condition of the Kampar Kiri river Gunung Sahilan village still quite good and still support for life of organisms that were in it and deserves to fishing activities in these waters
Multi-color Optical and NIR Light Curves of 64 Stripped-Envelope Core-Collapse Supernovae
We present a densely-sampled, homogeneous set of light curves of 64 low
redshift (z < 0.05) stripped-envelope supernovae (SN of type IIb, Ib, Ic and
Ic-bl). These data were obtained between 2001 and 2009 at the Fred L. Whipple
Observatory (FLWO) on Mt. Hopkins in Arizona, with the optical FLWO 1.2-m and
the near-infrared PAIRITEL 1.3-m telescopes. Our dataset consists of 4543
optical photometric measurements on 61 SN, including a combination of UBVRI,
UBVr'i', and u'BVr'i', and 2142 JHKs near-infrared measurements on 25 SN. This
sample constitutes the most extensive multi-color data set of stripped-envelope
SN to date. Our photometry is based on template-subtracted images to eliminate
any potential host galaxy light contamination. This work presents these
photometric data, compares them with data in the literature, and estimates
basic statistical quantities: date of maximum, color, and photometric
properties. We identify promising color trends that may permit the
identification of stripped-envelope SN subtypes from their photometry alone.
Many of these SN were observed spectroscopically by the CfA SN group, and the
spectra are presented in a companion paper (Modjaz et al. 2014). A thorough
exploration that combines the CfA photometry and spectroscopy of
stripped-envelope core-collapse SN will be presented in a follow-up paper.Comment: 26 pages, 17 figures, 8 tables. Revised version resubmitted to ApJ
Supplements after referee report. Additional online material is available
through http://cosmo.nyu.edu/SNYU
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