1,288 research outputs found
The first analytical expression to estimate photometric redshifts suggested by a machine
We report the first analytical expression purely constructed by a machine to
determine photometric redshifts () of galaxies. A simple and
reliable functional form is derived using galaxies from the Sloan
Digital Sky Survey Data Release 10 (SDSS-DR10) spectroscopic sample. The method
automatically dropped the and bands, relying only on , and
for the final solution. Applying this expression to other SDSS-DR10
galaxies, with measured spectroscopic redshifts (), we achieved a
mean and a scatter when averaged up to . The method was
also applied to the PHAT0 dataset, confirming the competitiveness of our
results when faced with other methods from the literature. This is the first
use of symbolic regression in cosmology, representing a leap forward in
astronomy-data-mining connection.Comment: 6 pages, 4 figures. Accepted for publication in MNRAS Letter
The Experience and Expression of Emotion in the Workplace: A Study of a Corrections Organization
This study evaluated Rafaeli and Sutton’s (1989) model of emotional expression in the workplace by examining descriptions of emotional interactions occurring among members of a state government agency. The results indicated that qualities of felt emotions influenced emotional expression, which in turn yielded changed relational perceptions and changed communication behavior subsequent to the emotional event. Content analysis of the event descriptions resulted in preliminary generalizations about the types of emotions experienced by members, the nature of repressed emotional messages, and the dimensions of relationship changes stemming from the emotional events. The results are interpreted as evidence of the importance of emotional communication in relationship reformulation and are consistent with Van Maanen and Kunda’s (1989) recent depiction of emotional control as part of organizational culture
Genealogies of rapidly adapting populations
The genetic diversity of a species is shaped by its recent evolutionary
history and can be used to infer demographic events or selective sweeps. Most
inference methods are based on the null hypothesis that natural selection is a
weak or infrequent evolutionary force. However, many species, particularly
pathogens, are under continuous pressure to adapt in response to changing
environments. A statistical framework for inference from diversity data of such
populations is currently lacking. Toward this goal, we explore the properties
of genealogies in a model of continual adaptation in asexual populations. We
show that lineages trace back to a small pool of highly fit ancestors, in which
almost simultaneous coalescence of more than two lineages frequently occurs.
While such multiple mergers are unlikely under the neutral coalescent, they
create a unique genetic footprint in adapting populations. The site frequency
spectrum of derived neutral alleles, for example, is non-monotonic and has a
peak at high frequencies, whereas Tajima's D becomes more and more negative
with increasing sample size. Since multiple merger coalescents emerge in many
models of rapid adaptation, we argue that they should be considered as a
null-model for adapting populations.Comment: to appear in PNA
Using gamma regression for photometric redshifts of survey galaxies
Machine learning techniques offer a plethora of opportunities in tackling big
data within the astronomical community. We present the set of Generalized
Linear Models as a fast alternative for determining photometric redshifts of
galaxies, a set of tools not commonly applied within astronomy, despite being
widely used in other professions. With this technique, we achieve catastrophic
outlier rates of the order of ~1%, that can be achieved in a matter of seconds
on large datasets of size ~1,000,000. To make these techniques easily
accessible to the astronomical community, we developed a set of libraries and
tools that are publicly available.Comment: Refereed Proceeding of "The Universe of Digital Sky Surveys"
conference held at the INAF - Observatory of Capodimonte, Naples, on
25th-28th November 2014, to be published in the Astrophysics and Space
Science Proceedings, edited by Longo, Napolitano, Marconi, Paolillo, Iodice,
6 pages, and 1 figur
A probabilistic approach to emission-line galaxy classification
We invoke a Gaussian mixture model (GMM) to jointly analyse two traditional
emission-line classification schemes of galaxy ionization sources: the
Baldwin-Phillips-Terlevich (BPT) and vs. [NII]/H
(WHAN) diagrams, using spectroscopic data from the Sloan Digital Sky Survey
Data Release 7 and SEAGal/STARLIGHT datasets. We apply a GMM to empirically
define classes of galaxies in a three-dimensional space spanned by the
[OIII]/H, [NII]/H, and EW(H), optical
parameters. The best-fit GMM based on several statistical criteria suggests a
solution around four Gaussian components (GCs), which are capable to explain up
to 97 per cent of the data variance. Using elements of information theory, we
compare each GC to their respective astronomical counterpart. GC1 and GC4 are
associated with star-forming galaxies, suggesting the need to define a new
starburst subgroup. GC2 is associated with BPT's Active Galaxy Nuclei (AGN)
class and WHAN's weak AGN class. GC3 is associated with BPT's composite class
and WHAN's strong AGN class. Conversely, there is no statistical evidence --
based on four GCs -- for the existence of a Seyfert/LINER dichotomy in our
sample. Notwithstanding, the inclusion of an additional GC5 unravels it. The
GC5 appears associated to the LINER and Passive galaxies on the BPT and WHAN
diagrams respectively. Subtleties aside, we demonstrate the potential of our
methodology to recover/unravel different objects inside the wilderness of
astronomical datasets, without lacking the ability to convey physically
interpretable results. The probabilistic classifications from the GMM analysis
are publicly available within the COINtoolbox
(https://cointoolbox.github.io/GMM\_Catalogue/).Comment: Accepted for publication in MNRA
Genotype-Phenotype Correlation in 153 Adult Patients With Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency: Analysis of the United Kingdom Congenital Adrenal Hyperplasia Adult Study Executive (CaHASE) Cohort
CONTEXT: In congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, a strong genotype-phenotype correlation exists in childhood. However, similar data in adults are lacking. OBJECTIVE: The objective of the study was to test whether the severity of disease-causing CYP21A2 mutations influences the treatment and health status in adults with CAH. RESEARCH DESIGN AND METHODS: We analyzed the genotype in correlation with treatment and health status in 153 adults with CAH from the United Kingdom Congenital adrenal Hyperplasia Adult Study Executive cohort. RESULTS: CYP21A2 mutations were distributed similarly to previously reported case series. In 7 patients a mutation was identified on only 1 allele. Novel mutations were detected on 1.7% of alleles (5 of 306). Rare mutations were found on 2.3% of alleles (7 of 306). For further analysis, patients were categorized into CYP21A2 mutation groups according to predicted residual enzyme function: null (n = 34), A (n = 42), B (n = 36), C (n = 34), and D (n = 7). Daily glucocorticoid dose was highest in group null and lowest in group C. Fludrocortisone was used more frequently in patients with more severe genotypes. Except for lower female height in group B, no statistically significant associations between genotype and clinical parameters were found. Androgens, blood pressure, lipids, blood glucose, and homeostasis model assessment of insulin resistance were not different between groups. Subjective health status was similarly impaired across groups. CONCLUSIONS: In adults with classic CAH and women with nonclassic CAH, there was a weak association between genotype and treatment, but health outcomes were not associated with genotype. The underrepresentation of males with nonclassic CAH may reflect that milder genotypes result in a milder condition that is neither diagnosed nor followed up in adulthood. Overall, our results suggest that the impaired health status of adults with CAH coming to medical attention is acquired rather than genetically determined and therefore could potentially be improved through modification of treatment
Child sexual abuse material in child-centred institutions: situational crime prevention approaches
This paper focuses on the potential for child-centred institutions to use situational crime prevention (SCP) strategies to prevent or reduce child sexual abuse material (CSAM)1 offending as a distinct form of child sexual abuse (CSA). We discuss the failure of the Royal Commission into Institutional Responses to Child Sexual Abuse in Australia to address the potential for CSAM offending to occur in child-centred institutions. Our premise is that CSAM offending is markedly shaped by the situation in which it occurs, rather than by any pre-existing preparedness to offend sexually against children. In this context, SCP for CSAM offending must be considered as part of overall strategies to combat CSA in institutional settings. However, we acknowledge that effective implementation of SCP in this area is not straightforward. We consider some of the challenges in implementing SCP at an institutional level
Functional consequences of seven novel mutations in the CYP11B1 Gene: four mutations associated with nonclassic and three mutations causing classic 11 -Hydroxylase Deficiency
Context: Steroid 11β-hydroxylase (CYP11B1) deficiency (11OHD) is the second most common form of congenital adrenal hyperplasia (CAH). Cases of nonclassic 11OHD are rare compared with the incidence of nonclassic 21-hydroxylase deficiency.
Objective: The aim of the study was to analyze the functional consequences of seven novel CYP11B1 mutations (p.M88I, p.W116G, p.P159L, p.A165D, p.K254_A259del, p.R366C, p.T401A) found in three patients with classic 11OHD, two patients with nonclassic 11OHD, and three heterozygous carriers for CYP11B1 mutations.
Methods: We conducted functional studies employing a COS7 cell in vitro expression system comparing wild-type (WT) and mutant CYP11B1 activity. Mutants were examined in a computational three-dimensional model of the CYP11B1 protein.
Results: All mutations (p.W116G, p.A165D, p.K254_A259del) found in patients with classic 11OHD have absent or very little 11β-hydroxylase activity relative to WT. The mutations detected in patients with nonclassic 11OHD showed partial functional impairment, with one patient being homozygous (p.P159L; 25% of WT) and the other patient compound heterozygous for a novel mild p.M88I (40% of WT) and the known severe p.R383Q mutation. The two mutations detected in heterozygous carriers (p.R366C, p.T401A) also reduced CYP11B1 activity by 23 to 37%, respectively.
Conclusion: Functional analysis results allow for the classification of novel CYP11B1 mutations as causative for classic and nonclassic 11OHD, respectively. Four partially inactivating mutations are predicted to result in nonclassic 11OHD. These findings double the number of mild CYP11B1 mutations previously described as associated with mild 11OHD. Our data are important to predict phenotypic expression and provide important information for clinical and genetic counseling i
Patient Satisfaction with a Pilot Chronic Pain Management Programme in Cape Town, South Africa
Background: The goals of a chronic pain management clinic includeincreasing patient knowledge about pain, developing pain management skillsand increasing patients’ confidence in their pain management abilities.A Chronic Pain Management Programme (CPMP) based on evidence basedguidelines was developed at a chronic pain management clinic to facilitatepatient discharge to a primary healthcare level. Aim: The aim of this study was to explore patient satisfaction with, acceptability of and the perceived success which could be due to the CPMP developed at the Chronic Pain Management Clinic of Groote Schuur Hospital,Cape Town.Methods: Patients (n=14) were referred to the pilot study from the Chronic Pain Management Clinic. A s a pilot, four courses were run over a period ofone year. In order to reach the research aim, an eleven-question, structuredopen-ended interview was conducted with all participants. Results: Fourteen patients enrolled in the CPMP. Responses were favourable with participants emphasising the roleof increased knowledge about pain, the role of exercise and of stress management techniques. Participants also recog-nised a positive change in behaviours and attitudes following participation in the CPMP.Conclusions: Findings suggest that participants found the format of the course acceptable as regards course content,structure and delivery. Participant responses suggest that the course was acceptable and perceived as useful. However,future courses would benefit from refresher courses or structured support groups
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