115 research outputs found
A hot cocoon in the ultralong GRB 130925A: hints of a PopIII-like progenitor in a low density wind environment
GRB 130925A is a peculiar event characterized by an extremely long gamma-ray
duration (7 ks), as well as dramatic flaring in the X-rays for
20 ks. After this period, its X-ray afterglow shows an atypical soft
spectrum with photon index 4, as observed by Swift and Chandra,
until s, when XMM-Newton observations uncover a harder spectral
shape with 2.5, commonly observed in GRB afterglows. We find that
two distinct emission components are needed to explain the X-ray observations:
a thermal component, which dominates the X-ray emission for several weeks, and
a non-thermal component, consistent with a typical afterglow. A forward shock
model well describes the broadband (from radio to X-rays) afterglow spectrum at
various epochs. It requires an ambient medium with a very low density wind
profile, consistent with that expected from a low-metallicity blue supergiant
(BSG). The thermal component has a remarkably constant size and a total energy
consistent with those expected by a hot cocoon surrounding the relativistic
jet. We argue that the features observed in this GRB (its ultralong duration,
the thermal cocoon, and the low density wind environment) are associated with a
low metallicity BSG progenitor and, thus, should characterize the class of
ultralong GRBs.Comment: 6 pgs, 3 figs, fig1 revised, ApJL in pres
Exile Vol. XVI No. 2
PREFACE 3
ESSAY
Observations At The Gap by Paul A. Dimitruk 4
Those Who Choose Words By Keith McWalter 5-6
On Victoria\u27s England by Paul A. Dimitruk 7-8
Facts Are The Enemy of Truth by Nancy Gutierrez
FICTION
Harmon by Barbara Mackey 22-25
Pilgrimage by Keith McWalter 35-44
ARTWORK
by Wandi Solez: 6, 15, 23, 27
by Ken Wernz 10
by Stephen Swift 11
by Laura M. Hyslop 12
by Skip Staudt 19
by W. A. Hoffman 25
by Mary Ann Kowaski 34
by Jo Ann Orgo 40
PHOTOGRAPHY
by Roger Block 16
by Tim Heath- all other
POETRY
My Poems by Susan Hallock 13
Counter-Fugue At Six-Thirty by Sherry Stodola 14-16
Apple Tree Poem by Darby Williams 17
When Snow Falls Into A Pond by Bruce Kidd 17
Woman-Man by Darby Williams 18
Transcendence by Wandi Solez 20
Paris Reflection by Wandi Solez 20
A Sleepless Night In Valencia, Spain by Wandi Solez 21
# 319 by Wandi Solez 21
Strange Lady by John Gillespie 26
Strange Lady II by John Gillespie 26
Where The Hell Is Rembrandt? by John Loveland 26
Years Ago by John Whitt 29
I\u27ve Finished Growing Now by Keith McWalter 29
Charisma by John Whitt 30
I Thought Of Cutting by John Loveland 31
Make Me Eat Peanut Butter by Fred Walton 31
The Cat by John Loveland 32
On The Rim by John Whitt 33
Undercurrent by Keith McWalter 33
Cover: Gail Lutsch
Layouts: Keith McWalte
Embracing ligands. Synthesis, characterisation and the correlation between 59Co NMR and ligand field parameters of Co(III) complexes with a new class of nitrogen-thioether multidentate ligand
The syntheses of the hexadentate ligands 2,2,10,10-tetra(methyleneamine)-4,8-dithiaundecane (PrN(4)S(2)amp), 2,2,11,11-tetra(methyleneamine)-4,9-dithiadodecane (BuN(4)S(2)amp), and 1,2-bis(4,4-methyleneamine)-2-thiapentyl)benzene (XyN(4)S(2)amp) are reported and the complexes [Co(RN(4)S(2)amp)](3+) (R = Pr, Bu, Xy) characterised by single crystal X-ray study. The low-temperature (11 K) absorption spectra have been measured in Nafion films. From the observed positions of both spin-allowed (1)A(1g) --> T-1(1g) and (1)A(1g) --> T-1(2g) and spin forbidden (1)A(1g) --> T-3(1g) and (1)A(1g) --> T-3(2g) bands, octahedral ligand-field parameters (10D(q), B and C) have been determined. DFT calculations suggest that significant interaction between the d-d and CT excitations occurs for the complexes. The calculations offer an explanation for the observed deviations from linearity of the relationship between Co-59 magnetogyric ratio and beta(DeltaE)(-1) (beta = the nephelauxetic ratio; DeltaE the energy of the (1)A(1g) --> T-1(1g) transition) for a series of amine and mixed amine/thioether donor complexes
Sports-based intervention and the problem of youth offending: a diverse enough tool for a diverse society?
This paper discusses sports-based interventions (SBIs) and the problem of youth crime. It notes the positive role sport can play in changing to better the lives of young people. However, there is a lack of robust evidence to support the argument that participation in sporting activity can lead to a reduction in anti-social and offending behaviour. The paper discusses how through focusing on ‘individual needs’ and ‘pathways to work’, SBIs can become overly reductionist and mask broader structural class-, gender- and race-based inequalities that permeate through neoliberal nation-states and western criminal justice systems. It concludes that SBI advocates must seek to promote a less homogeneous idea of what an SBI is, as well as be more sensitive to the diverse needs of young people, particularly if they are to tackle the underlying structural inequalities that arguably create the social problem, that is youth crime in the first place
Extracellular Fibrils of Pathogenic Yeast Cryptococcus gattii Are Important for Ecological Niche, Murine Virulence and Human Neutrophil Interactions
Cryptococcus gattii, an emerging fungal pathogen of humans and animals, is found on a variety of trees in tropical and temperate regions. The ecological niche and virulence of this yeast remain poorly defined. We used Arabidopsis thaliana plants and plant-derived substrates to model C. gattii in its natural habitat. Yeast cells readily colonized scratch-wounded plant leaves and formed distinctive extracellular fibrils (40–100 nm diameter ×500–3000 nm length). Extracellular fibrils were observed on live plants and plant-derived substrates by scanning electron microscopy (SEM) and by high voltage- EM (HVEM). Only encapsulated yeast cells formed extracellular fibrils as a capsule-deficient C. gattii mutant completely lacked fibrils. Cells deficient in environmental sensing only formed disorganized extracellular fibrils as apparent from experiments with a C. gattii STE12α mutant. C. gattii cells with extracellular fibrils were more virulent in murine model of pulmonary and systemic cryptococcosis than cells lacking fibrils. C. gattii cells with extracellular fibrils were also significantly more resistant to killing by human polymorphonuclear neutrophils (PMN) in vitro even though these PMN produced elaborate neutrophil extracellular traps (NETs). These observations suggest that extracellular fibril formation could be a structural adaptation of C. gattii for cell-to-cell, cell-to-substrate and/or cell-to- phagocyte communications. Such ecological adaptation of C. gattii could play roles in enhanced virulence in mammalian hosts at least initially via inhibition of host PMN– mediated killing
MiR-218 Inhibits Invasion and Metastasis of Gastric Cancer by Targeting the Robo1 Receptor
MicroRNAs play key roles in tumor metastasis. Here, we describe the regulation and function of miR-218 in gastric cancer (GC) metastasis. miR-218 expression is decreased along with the expression of one of its host genes, Slit3 in metastatic GC. However, Robo1, one of several Slit receptors, is negatively regulated by miR-218, thus establishing a negative feedback loop. Decreased miR-218 levels eliminate Robo1 repression, which activates the Slit-Robo1 pathway through the interaction between Robo1 and Slit2, thus triggering tumor metastasis. The restoration of miR-218 suppresses Robo1 expression and inhibits tumor cell invasion and metastasis in vitro and in vivo. Taken together, our results describe a Slit-miR-218-Robo1 regulatory circuit whose disruption may contribute to GC metastasis. Targeting miR-218 may provide a strategy for blocking tumor metastasis
Developing a computerised search to help UK General Practices identify more patients for palliative care planning:a feasibility study
We would like to thank all practices, patients and their carers who helped us successfully conduct this project. We are grateful for advice from Libby Morris, the eHealth Clinical Lead for NHS Scotland and a GP in Lothian. The project was funded by Marie Curie Cancer Care (ref A13575).Peer reviewedPublisher PD
Environmentally Realistic Exposure to the Herbicide Atrazine Alters Some Sexually Selected Traits in Male Guppies
Male mating signals, including ornaments and courtship displays, and other sexually selected traits, like male-male aggression, are largely controlled by sex hormones. Environmental pollutants, notably endocrine disrupting compounds, can interfere with the proper functioning of hormones, thereby impacting the expression of hormonally regulated traits. Atrazine, one of the most widely used herbicides, can alter sex hormone levels in exposed animals. I tested the effects of environmentally relevant atrazine exposures on mating signals and behaviors in male guppies, a sexually dimorphic freshwater fish. Prolonged atrazine exposure reduced the expression of two honest signals: the area of orange spots (ornaments) and the number of courtship displays performed. Atrazine exposure also reduced aggression towards competing males in the context of mate competition. In the wild, exposure levels vary among individuals because of differential distribution of the pollutants across habitats; hence, differently impacted males often compete for the same mates. Disrupted mating signals can reduce reproductive success as females avoid mating with perceptibly suboptimal males. Less aggressive males are at a competitive disadvantage and lose access to females. This study highlights the effects of atrazine on ecologically relevant mating signals and behaviors in exposed wildlife. Altered reproductive traits have important implications for population dynamics, evolutionary patterns, and conservation of wildlife species
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