3,036 research outputs found

    A complete record from colonization to extinction reveals density dependence and the importance of winter conditions for a population of the silvery blue, Glaucopsyche lygdamus.

    Get PDF
    Butterflies in the family Lycaenidac are often the focus of conservation efforts. However, our understanding of lycaenid population dynamics has been limited to relatively few examples of long-term monitoring data that have been reported. Here, factors associated with population regulation are investigated using a complete record of a single population of the silvery blue, Glaucopsyche lygdamus Doubleday (Lepidoptera: Lycaenidae). Adults of G. lygdamus were first observed in an annual grassland near Davis, California, in 1982 and were last seen in 2003. Relationships between inter-annual variation in abundance and climatic variables were examined, accounting for density dependent effects. Significant effects of both negative density dependence and climatic variation were detected, particularly precipitation and temperature during winter months. Variation in precipitation, the strongest predictor of abundance, was associated directly and positively with butterfly abundance in the same year. Winter temperatures had a negative effect in the same year, but had a lagged, positive effect on abundance in the subsequent year. Mechanistic hypotheses are posed that include climatic effects mediated through both larval and adult plant resources

    Early changes in brain structure correlate with language outcomes in children with neonatal encephalopathy.

    Get PDF
    Global patterns of brain injury correlate with motor, cognitive, and language outcomes in survivors of neonatal encephalopathy (NE). However, it is still unclear whether local changes in brain structure predict specific deficits. We therefore examined whether differences in brain structure at 6 months of age are associated with neurodevelopmental outcomes in this population. We enrolled 32 children with NE, performed structural brain MR imaging at 6 months, and assessed neurodevelopmental outcomes at 30 months. All subjects underwent T1-weighted imaging at 3 T using a 3D IR-SPGR sequence. Images were normalized in intensity and nonlinearly registered to a template constructed specifically for this population, creating a deformation field map. We then used deformation based morphometry (DBM) to correlate variation in the local volume of gray and white matter with composite scores on the Bayley Scales of Infant and Toddler Development (Bayley-III) at 30 months. Our general linear model included gestational age, sex, birth weight, and treatment with hypothermia as covariates. Regional brain volume was significantly associated with language scores, particularly in perisylvian cortical regions including the left supramarginal gyrus, posterior superior and middle temporal gyri, and right insula, as well as inferior frontoparietal subcortical white matter. We did not find significant correlations between regional brain volume and motor or cognitive scale scores. We conclude that, in children with a history of NE, local changes in the volume of perisylvian gray and white matter at 6 months are correlated with language outcome at 30 months. Quantitative measures of brain volume on early MRI may help identify infants at risk for poor language outcomes

    A discursive psychology analysis of emotional support for men with colorectal cancer

    Get PDF
    Recent research into both masculinity and health, and the provision of social support for people with cancer has focussed upon the variations that may underlie broad assumptions about masculine health behaviour. The research reported here pursues this interest in variation by addressing the discursive properties of talk about emotional support, by men with colorectal cancer - an understudied group in the social support and cancer literature. Semi-structured interviews were conducted with eight men with colorectal cancer, and the transcripts analysed using an intensive discursive psychology approach. From this analysis two contrasting approaches to this group of men’s framing of emotional support in the context of cancer are described. First, talk about cancer was positioned as incompatible with preferred masculine identities. Second, social contact that affirms personal relationships was given value, subject to constraints arising from discourses concerning appropriate emotional expression. These results are discussed with reference to both the extant research literature on masculinity and health, and their clinical implications, particularly the advice on social support given to older male cancer patients, their families and friends

    On the exact open-closed vertex in plane-wave light-cone string field theory

    Full text link
    The open-closed vertex in the maximally supersymmetric type IIB plane-wave light-cone string field theory is considered and an explicit solution for the bosonic part of the vertex is derived, valid for all values of the mass parameter, \mu. This vertex is of relevance to IIB plane-wave orientifolds, as well as IIB plane-wave strings in the presence of D-branes and their gauge theory duals. Methods of complex analysis are used to develop a systematic procedure for obtaining the solution. This procedure is first applied to the vertex in flat space and then extended to the plane-wave case. The plane-wave solution for the vertex requires introducing certain ``\mu-deformed Gamma functions'', which are generalizations of the ordinary Gamma function. The behaviour of the Neumann matrices is graphically illustrated and their large-\mu asymptotics are analysed.Comment: 35 pages, 7 figures; v4: minor changes in appendi

    A prospective study of von Willebrand factor levels and bleeding in pregnant women with type 1 von Willebrand disease

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134934/1/hae13086.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134934/2/hae13086_am.pd

    High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods

    Get PDF
    An improved single-cell photonic band-gap (PBG) structure with an inner row of elliptical rods (PBG-E) was tested with high power at a 60 Hz repetition rate at X-band (11.424 GHz), achieving a gradient of 128  MV/m at a breakdown probability of 3.6×10-3 per pulse per meter at a pulse length of 150 ns. The tested standing-wave structure was a single high-gradient cell with an inner row of elliptical rods and an outer row of round rods; the elliptical rods reduce the peak surface magnetic field by 20% and reduce the temperature rise of the rods during the pulse by several tens of degrees, while maintaining good damping and suppression of high order modes. When compared with a single-cell standing-wave undamped disk-loaded waveguide structure with the same iris geometry under test at the same conditions, the PBG-E structure yielded the same breakdown rate within measurement error. The PBG-E structure showed a greatly reduced breakdown rate compared with earlier tests of a PBG structure with round rods, presumably due to the reduced magnetic fields at the elliptical rods vs the fields at the round rods, as well as use of an improved testing methodology. A post-testing autopsy of the PBG-E structure showed some damage on the surfaces exposed to the highest surface magnetic and electric fields. Despite these changes in surface appearance, no significant change in the breakdown rate was observed in testing. These results demonstrate that PBG structures, when designed with reduced surface magnetic fields and operated to avoid extremely high pulsed heating, can operate at breakdown probabilities comparable to undamped disk-loaded waveguide structures and are thus viable for high-gradient accelerator applications.United States. Dept. of Energy. High Energy Physics Division (Contract DEFG02-91ER40648

    Association Between Timing of Antibiotic Administration and Mortality from Septic Shock in Patients Treated with a Quantitative Resuscitation Protocol

    Get PDF
    Objective We sought to determine the association between time to initial antibiotics and mortality of septic shock patients treated with an emergency department (ED) based early resuscitation protocol. Design Pre-planned analysis of a multicenter randomized controlled trial of early sepsis resuscitation. Setting 3 urban US EDs. Patients Adult septic shock patients. Interventions A quantitative resuscitation protocol in the ED targeting 3 physiological variables: central venous pressure, mean arterial pressure and either central venous oxygen saturation or lactate clearance. The study protocol was continued until all endpoints were achieved or a maximum of 6 hours. Measurements Data on patients who received an initial dose of antibiotics after presentation to the ED were categorized based on both time from triage and time from shock recognition to initiation of antibiotics. The primary outcome was in-hospital mortality. Main Results Of 291 included patients, mortality did not change with hourly delays in antibiotic administration up to 6 hours after triage: 1 hour (OR 1.2, 0.6–2.5), 2 hours (OR 0.71, 0.4–1.3), 3 hours (OR 0.59, 0.3–1.3). Mortality was significantly increased patients who received initial antibiotics after shock recognition (N=172, 59%) compared with before shock recognition (OR 2.4, 1.1–4.5); however, among patients who received antibiotics after shock recognition, mortality did not change with hourly delays in antibiotic administration. Conclusion In this large, prospective study of ED patients with septic shock, we found no increase in mortality with each hour delay to administration of antibiotics after triage. However, delay in antibiotics until after shock recognition was associated with increased mortality
    • 

    corecore