343 research outputs found
The giant, horizontal and asymptotic branches of galactic globular clusters. I. The catalog, photometric observables and features
A catalog including a set of the most recent Color Magnitude Diagrams (CMDs)
is presented for a sample of 61 Galactic Globular Clusters (GGCs). We used this
data-base to perform an homogeneous systematic analysis of the evolved
sequences (namely, Red Giant Branch (RGB), Horizontal Branch (HB) and
Asymptotic Giant Branch (AGB)). Based on this analysis, we present: (1) a new
procedure to measure the level of the ZAHB (V_ZAHB) and an homogeneous set of
distance moduli obtained adopting the HB as standard candle; (2) an independent
estimate for RGB metallicity indicators and new calibrations of these
parameters in terms of both spectroscopic ([Fe/H]_CG97) and global metallicity
([M/H], including also the alpha-elements enhancement). The set of equations
presented can be used to simultaneously derive a photometric estimate of the
metal abundance and the reddening from the morphology and the location of the
RGB in the (V,B-V)-CMD. (3) the location of the RGB-Bump (in 47 GGCs) and the
AGB-Bump (in 9 GGCs). The dependence of these features on the metallicity is
discussed. We find that by using the latest theoretical models and the new
metallicity scales the earlier discrepancy between theory and observations
(~0.4 mag) completely disappears.Comment: 51 pages, 23 figures, AAS Latex, macro rtrpp4.sty included, accepted
by A
Epidemiological study of Trichosporon asahii infections over the past 23 years
Trichosporon is a yeast-like basidiomycete, a conditional pathogenic fungus that is rare in the clinic but often causes fatal infections in immunocompromised individuals. Trichosporon asahii is the most common pathogenic fungus in this genus and the occurrence of infections has dramatically increased in recent years. Here, we report a systematic literature review detailing 140 cases of T. asahii infection reported during the past 23 years. Statistical analysis shows that T. asahii infections were most frequently reported within immunodeficient or immunocompromised patients commonly with blood diseases. Antibiotic use, invasive medical equipment and chemotherapy were the leading risk factors for acquiring infection. In vitro susceptibility, clinical information and prognosis analysis showed that voriconazole is the primary drug of choice in the treatment of T. asahii infection. Combination treatment with voriconazole and amphotericin B did not show superiority over either drug alone. Finally, we found that the types of infections prevalent in China are significantly different from those in other countries. These results provide detailed information and relevant clinical treatment strategies for the diagnosis and treatment of T. asahii infection
Cauchy's infinitesimals, his sum theorem, and foundational paradigms
Cauchy's sum theorem is a prototype of what is today a basic result on the
convergence of a series of functions in undergraduate analysis. We seek to
interpret Cauchy's proof, and discuss the related epistemological questions
involved in comparing distinct interpretive paradigms. Cauchy's proof is often
interpreted in the modern framework of a Weierstrassian paradigm. We analyze
Cauchy's proof closely and show that it finds closer proxies in a different
modern framework.
Keywords: Cauchy's infinitesimal; sum theorem; quantifier alternation;
uniform convergence; foundational paradigms.Comment: 42 pages; to appear in Foundations of Scienc
CMB-S4 Science Book, First Edition
This book lays out the scientific goals to be addressed by the
next-generation ground-based cosmic microwave background experiment, CMB-S4,
envisioned to consist of dedicated telescopes at the South Pole, the high
Chilean Atacama plateau and possibly a northern hemisphere site, all equipped
with new superconducting cameras. CMB-S4 will dramatically advance cosmological
studies by crossing critical thresholds in the search for the B-mode
polarization signature of primordial gravitational waves, in the determination
of the number and masses of the neutrinos, in the search for evidence of new
light relics, in constraining the nature of dark energy, and in testing general
relativity on large scales
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
Fitting the integrated Spectral Energy Distributions of Galaxies
Fitting the spectral energy distributions (SEDs) of galaxies is an almost
universally used technique that has matured significantly in the last decade.
Model predictions and fitting procedures have improved significantly over this
time, attempting to keep up with the vastly increased volume and quality of
available data. We review here the field of SED fitting, describing the
modelling of ultraviolet to infrared galaxy SEDs, the creation of
multiwavelength data sets, and the methods used to fit model SEDs to observed
galaxy data sets. We touch upon the achievements and challenges in the major
ingredients of SED fitting, with a special emphasis on describing the interplay
between the quality of the available data, the quality of the available models,
and the best fitting technique to use in order to obtain a realistic
measurement as well as realistic uncertainties. We conclude that SED fitting
can be used effectively to derive a range of physical properties of galaxies,
such as redshift, stellar masses, star formation rates, dust masses, and
metallicities, with care taken not to over-interpret the available data. Yet
there still exist many issues such as estimating the age of the oldest stars in
a galaxy, finer details ofdust properties and dust-star geometry, and the
influences of poorly understood, luminous stellar types and phases. The
challenge for the coming years will be to improve both the models and the
observational data sets to resolve these uncertainties. The present review will
be made available on an interactive, moderated web page (sedfitting.org), where
the community can access and change the text. The intention is to expand the
text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics &
Space Scienc
Report of the Topical Group on Dark Energy and Cosmic Acceleration: Complementarity of Probes and New Facilities for Snowmass 2021
The mechanism(s) driving the early- and late-time accelerated expansion of
the Universe represent one of the most compelling mysteries in fundamental
physics today. The path to understanding the causes of early- and late-time
acceleration depends on fully leveraging ongoing surveys, developing and
demonstrating new technologies, and constructing and operating new instruments.
This report presents a multi-faceted vision for the cosmic survey program in
the 2030s and beyond that derives from these considerations. Cosmic surveys
address a wide range of fundamental physics questions, and are thus a unique
and powerful component of the HEP experimental portfolio.Comment: Submitted to the Proceedings of the US Community Study on the Future
of Particle Physics (Snowmass 2021); Topical Group Report for CF06 (Cosmic
Frontier Topical Group on Dark Energy and Cosmic Acceleration:
Complementarity of Probes and New Facilitie
Dissection of a QTL Hotspot on Mouse Distal Chromosome 1 that Modulates Neurobehavioral Phenotypes and Gene Expression
A remarkably diverse set of traits maps to a region on mouse distal chromosome 1 (Chr 1) that corresponds to human Chr 1q21–q23. This region is highly enriched in quantitative trait loci (QTLs) that control neural and behavioral phenotypes, including motor behavior, escape latency, emotionality, seizure susceptibility (Szs1), and responses to ethanol, caffeine, pentobarbital, and haloperidol. This region also controls the expression of a remarkably large number of genes, including genes that are associated with some of the classical traits that map to distal Chr 1 (e.g., seizure susceptibility). Here, we ask whether this QTL-rich region on Chr 1 (Qrr1) consists of a single master locus or a mixture of linked, but functionally unrelated, QTLs. To answer this question and to evaluate candidate genes, we generated and analyzed several gene expression, haplotype, and sequence datasets. We exploited six complementary mouse crosses, and combed through 18 expression datasets to determine class membership of genes modulated by Qrr1. Qrr1 can be broadly divided into a proximal part (Qrr1p) and a distal part (Qrr1d), each associated with the expression of distinct subsets of genes. Qrr1d controls RNA metabolism and protein synthesis, including the expression of ∼20 aminoacyl-tRNA synthetases. Qrr1d contains a tRNA cluster, and this is a functionally pertinent candidate for the tRNA synthetases. Rgs7 and Fmn2 are other strong candidates in Qrr1d. FMN2 protein has pronounced expression in neurons, including in the dendrites, and deletion of Fmn2 had a strong effect on the expression of few genes modulated by Qrr1d. Our analysis revealed a highly complex gene expression regulatory interval in Qrr1, composed of multiple loci modulating the expression of functionally cognate sets of genes
Nonhumans in participatory design
© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. This article examines the role that nonhumans play in participatory design. Research and practice concerned with participatory design mostly focuses on human participants, however nonhumans also participate in the design process and can play a significant role in shaping the process. This article focuses on how nonhumans participate in the design process. An empirical case study is used to illustrate how humans and nonhumans assemble to form networks in order to effect a design. Nonhumans increase the level of participation in a design process. The case study reveals how nonhumans help to maintain, destroy or strengthen networks by substituting, mediating and communicating with humans and often, in doing so, making human actors more or less visible in the process. Nonhumans play a part in configuring the social. Revealing the presence and roles of nonhumans is an important means through which to increase the democracy within the design process
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