Line Profiles of Cores within Clusters. III. What is the most reliable tracer of core collapse in dense clusters?

Recent observational and theoretical investigations have emphasised the importance of filamentary networks within molecular clouds as sites of star formation. Since such environments are more complex than those of isolated cores, it is essential to understand how the observed line profiles from collapsing cores with non-spherical geometry are affected by filaments. In this study, we investigate line profile asymmetries by performing radiative transfer calculations on hydrodynamic models of three collapsing cores that are embedded in filaments. We compare the results to those that are expected for isolated cores. We model the five lowest rotational transition line (J = 1-0, 2-1, 3-2, 4-3, and 5-4) of both optically thick (HCN, HCO$^+$) as well as optically thin (N$_2$H$^+$, H$^{13}$CO$^+$) molecules using constant abundance laws. We find that less than 50% of simulated (1-0) transition lines show blue infall asymmetries due to obscuration by the surrounding filament. However, the fraction of collapsing cores that have a blue asymmetric emission line profile rises to 90% when observed in the (4-3) transition. Since the densest gas towards the collapsing core can excite higher rotational states, upper level transitions are more likely to produce blue asymmetric emission profiles. We conclude that even in irregular, embedded cores one can trace infalling gas motions with blue asymmetric line profiles of optically thick lines by observing higher transitions. The best tracer of collapse motions of our sample is the (4-3) transition of HCN, but the (3-2) and (5-4) transitions of both HCN and HCO$^+$ are also good tracers.Comment: accepted by MNRAS; 13 pages, 16 figures, 6 table

The interface between intrapreneurship, innovation and IT governance

The purpose of this conceptual paper is to examine the links, as reported in the international literature, between intrapreneurship, innovativeness and IT governance within medium to large organizations. A cross disciplinary literature review was conducted and yielded a theoretical framework for identifying and understanding the critical elements underpinning and driving innovation and intrapreneurship performance and their relationship with key aspects of IT governance within organizations.<br /

Integrative Taxonomy, a New Tool for Fisheries Conservation

Species delimitation is becoming increasingly objective and integrative. Sequence capture approaches allow collection of 1000s of loci for 100s of individuals. New approaches address the computational challenges of large datasets and offer potential for genome-wide sampling of variation at different evolutionary scales. These new approaches also allow integration of genetic and non-genetic data in a unified framework. Despite these advances, few studies have attempted to combine genetic and morphological data for delimiting species. Hakes (Merluccius spp.) are an ideal group for an empirical test of the power and applicability of these new methods because they are morphologically conserved and have distributional patterns ideal for studying a broad range of evolutionary questions. They also are of economic and conservation concern so the results of this phylogenetic study can be directly applied to fisheries management. Hakes are demersal fishes that inhabit the continental shelf and slope of the Atlantic, Pacific, and around New Zealand and there are 16 putative species. Hakes can be difficult to identify due to their conservative external morphology and high level of intraspecific variation, resulting in serious identification problems. Many species of hakes are sympatric and there is moderate ecological overlap. Unresolved alpha taxonomy and the lack of diagnostic characters have led to mixed-species in landings data, making management and conservation difficult. This study uses a broad taxonomic and geographic sampling combined with new morphological and genetic characters to clarify the taxonomy, systematics and the global biogeography and diversification of hake species

Assessing Child Obesity and Physical Activity in a Hard-to-Reach Population in California's Central Valley, 2012-2013.

IntroductionIn California's agricultural Central Valley, the rate of childhood obesity is higher than the national average. Adequate physical activity contributes to obesity prevention and its assessment is useful to evaluate the impact of interventions.MethodsNiños Sanos, Familia Sana (Healthy Children, Healthy Family [NSFS]) uses community-based participatory research to implement an intervention program to reduce childhood obesity among people of Mexican origin in the Central Valley. Anthropometric measurements were conducted on more than 650 children enrolled in NSFS. Physical activity data from a subgroup of children aged 4 to 7 years (n = 134) were collected via a wearable accelerometer.ResultsChildren were classified on the basis of age and sex-adjusted body mass index as healthy weight (57.7%); overweight (19.3%), or obese (23%). Logistic regression showed that moderate to vigorous physical activity (MVPA) was associated with a child's likelihood of having a healthy BMI (odds ratio: 1.03; 95% CI, 1.01-1.05; P = .017).ConclusionNSFS's community-based participatory approach resulted in successful use of a commercial electronic device to measure physical activity quantity and quality in this hard-to-reach population. Promotion of adequate daily MVPA is an appropriate and necessary component of NSFS's childhood obesity prevention strategy

Education/Connection/Action: Community Literacies and Shared Knowledges as Creative Productions for Social Justice

This article highlights Education/Connection/Action (ECA), a locally developed community pedagogy deployed at a youth activism summer camp that served as a site for a community/academic teaching and research collaboration. Youth considered connections between a set of issues, including a local ban on Ethnic Studies, the School-to-Prison Pipeline, and Youth Sexuality, Health, and Rights. They drew from lived and learned literacies to inform participatory media projects that critically and creatively address restrictions on access to local knowledges and information with particular relevance to youth sexuality, health, and rights (broadly defined). In highlighting youth voices, desires, and needs across distinct youth communities, their collaborative productions demonstrate coalitional potential and a collective call for change

LP 400-22, A very low-mass and high-velocity white dwarf

We report the identification of LP 400-22 (WD 2234+222) as a very low-mass and high-velocity white dwarf. The ultraviolet GALEX and optical photometric colors and a spectral line analysis of LP 400-22 show this star to have an effective temperature of 11080+/-140 K and a surface gravity of log g = 6.32+/-0.08. Therefore, this is a helium core white dwarf with a mass of 0.17 M_solar. The tangential velocity of this white dwarf is 414+/-43 km/s, making it one of the fastest moving white dwarfs known. We discuss probable evolutionary scenarios for this remarkable object.Comment: accepted for publication in ApJ Letters, made minor correction

Confronting Sources of Systematic Error to Resolve Historically Contentious Relationships: A Case Study Using Gadiform Fishes (Teleostei, Paracanthopterygii, Gadiformes)

Reliable estimation of phylogeny is central to avoid inaccuracy in downstream macroevolutionary inferences. However, limitations exist in the implementation of concatenated and summary coalescent approaches, and Bayesian and full coalescent inference methods may not yet be feasible for computation of phylogeny using complicated models and large data sets. Here, we explored methodological (e.g., optimality criteria, character sampling, model selection) and biological (e.g., heterotachy, branch length heterogeneity) sources of systematic error that can result in biased or incorrect parameter estimates when reconstructing phylogeny by using the gadiform fishes as a model clade. Gadiformes include some of the most economically important fishes in the world (e.g., Cods, Hakes, and Rattails). Despite many attempts, a robust higher-level phylogenetic framework was lacking due to limited character and taxonomic sampling, particularly from several species-poor families that have been recalcitrant to phylogenetic placement. We compiled the first phylogenomic data set, including 14,208 loci (⁠\u3e role= presentation \u3e\u3e2.8 M bp) from 58 species representing all recognized gadiform families, to infer a time-calibrated phylogeny for the group. Data were generated with a gene-capture approach targeting coding DNA sequences from single-copy protein-coding genes. Species-tree and concatenated maximum-likelihood (ML) analyses resolved all family-level relationships within Gadiformes. While there were a few differences between topologies produced by the DNA and the amino acid data sets, most of the historically unresolved relationships among gadiform lineages were consistently well resolved with high support in our analyses regardless of the methodological and biological approaches used. However, at deeper levels, we observed inconsistency in branch support estimates between bootstrap and gene and site coefficient factors (gCF, sCF). Despite numerous short internodes, all relationships received unequivocal bootstrap support while gCF and sCF had very little support, reflecting hidden conflict across loci. Most of the gene-tree and species-tree discordance in our study is a result of short divergence times, and consequent lack of informative characters at deep levels, rather than incomplete lineage sorting. We use this phylogeny to establish a new higher-level classification of Gadiformes as a way of clarifying the evolutionary diversification of the order. We recognize 17 families in five suborders: Bregmacerotoidei, Gadoidei, Ranicipitoidei, Merluccioidei, and Macrouroidei (including two subclades). A time-calibrated analysis using 15 fossil taxa suggests that Gadiformes evolved ∼ role= presentation \u3e∼79.5 Ma in the late Cretaceous, but that most extant lineages diverged after the Cretaceous–Paleogene (K-Pg) mass extinction (66 Ma). Our results reiterate the importance of examining phylogenomic analyses for evidence of systematic error that can emerge as a result of unsuitable modeling of biological factors and/or methodological issues, even when data sets are large and yield high support for phylogenetic relationships. [Branch length heterogeneity; Codfishes; commercial fish species; Cretaceous-Paleogene (K-Pg); heterotachy; systematic error; target enrichment.