433 research outputs found
Hot Horizontal Branch Stars in the Galactic Bulge. I
We present the first results of a survey of blue horizontal branch (BHB)
stars in the Galactic bulge. 164 candidates with 15 < V < 17.5 in a field
7.5deg from the Galactic Center were observed in the blue at 2.4A FWHM
resolution with the AAT 2dF spectrograph. Radial velocities were measured for
all stars. For stars with strong Balmer lines, their profiles were matched to
theoretical spectrum calculations to determine stellar temperature Teff and
gravity log g; matches to metal lines yielded abundances. CTIO UBV photometry
then gave the reddening and distance to each hot star. Reddening was found to
be highly variable, with E(B-V) from 0.0 to 0.55 around a mean of 0.28.
Forty-seven BHB candidates were identified with Teff >= 7250K, of which seven
have the gravities of young stars, three are ambiguous, and 37 are HB stars.
They span a wide metallicity range, from solar to 1/300 solar. The warmer BHB's
are more metal-poor and loosely concentrated towards the Galactic center, while
the cooler ones are of somewhat higher metallicity and closer to the center.
Their red B-V colors overlap main-sequence stars, but the U-B vs. B-V diagram
separates them until E(B-V) > 0.5. We detect two cool solar-metallicity HB
stars in the bulge of our own Galaxy, the first such stars known. Still elusive
are their hot counterparts, the metal-rich sdB/O stars causing excess UV light
in metal-rich galaxies; they have V ~ 20.5 in the Bulge.Comment: 29 pages, 4 figures (the third with 4 panels, the fourth with 2
panels). To appear in the Astrophysical Journal v571n1, Jan. 20, 2000.
Abstract is shortened here, and figures compresse
The Effect of Hemoglobin Levels on Mortality in Pediatric Patients with Severe Traumatic Brain Injury
Objective. There is increasing evidence of adverse outcomes associated with blood transfusions for adult traumatic brain injury patients. However, current evidence suggests that pediatric traumatic brain injury patients may respond to blood transfusions differently on a vascular level. This study examined the influence of blood transfusions and anemia on the outcome of pediatric traumatic brain injury patients. Design. A retrospective cohort analysis of severe pediatric traumatic brain injury (TBI) patients was undertaken to investigate the association between blood transfusions and anemia on patient outcomes. Measurements and Main Results. One hundred and twenty patients with severe traumatic brain injury were identified and included in the analysis. The median Glasgow Coma Scale (GCS) was 6 and the mean hemoglobin (Hgb) on admission was 115.8 g/L. Forty-three percent of patients (43%) received at least one blood transfusion and the mean hemoglobin before transfusion was 80.1 g/L. Multivariable regression analysis revealed that anemia and the administration of packed red blood cells were not associated with adverse outcomes. Factors that were significantly associated with mortality were presence of abusive head trauma, increasing PRISM score, and low GCS after admission. Conclusion. In this single centre retrospective cohort study, there was no association found between anemia, blood transfusions, and hospital mortality in a pediatric traumatic brain injury patient population. Background Traumatic brain injury (TBI) is a leading cause of pediatric morbidity and mortality, accounting for approximately 60,000 hospitalizations and 7,400 deaths per year While the current adult literature is gaining increasing evidence that there may be an adverse effect of transfusion on TBI patients, these results may not be generalizable to pediatric patients. Significant differences exist between pediatric and adult cerebral blood flow (CBF) in both normal and traumatic-injured states Further, pediatric TBI patients may respond to blood transfusions differently compared to adults. Figaji et al. reported that 79% of their pediatric TBI patients demonstrated an improvement in brain oxygenation after a transfusion The Transfusion Requirements in Pediatric Intensive Care Unit (TRIPICU) trial demonstrated that adopting a restrictive blood transfusion threshold of a hemoglobin (Hgb) level of 70 g/L in stable critically ill children results in no difference in mortality, but they did not look at TBI patients specifically Materials and Methods Approval from the Conjoint Health Research Ethics Board at the University of Calgary was obtained (Study ID REB13-0095) and informed consent was waived. Patients with a diagnosis of TBI admitted to the Alberta Children's Hospital (ACH) PICU between January 2001 and December 2012 had their charts analyzed by the study investigators. Inclusion criteria were <18 years of age, admission to ACH PICU with diagnosis of TBI or skull fracture, and initial Glasgow Coma Scale (GCS) of ≤8. Exclusion criteria included patient obeying commands within 12 hours of admission, patient death within 12 hours of admission (with injuries likely so severe that blood transfusions would be unlikely to alter their course), nontraumatic etiology to explain decreased level of consciousness (e.g., alcohol or drugs), and concomitant traumatic quadriparesis (unable to assess GCS). These criteria were modelled after a similar study in adult TBI patients Data was collected on standardized case report forms. Aside from standard demographic information, additional data collected included patient initial hemoglobin and mean hemoglobin for up to the next 7 days after admission; type and severity of the injury characterized by initial vital signs and GCS scores; mechanism of injury; surgical procedures performed; and the presence of signs indicative of raised intracranial pressure (ICP) on CT scans, as reported by a radiologist. At our institution, all patients with severe TBI receive radiologic studies as part of their workup, but not all patients receive invasive ICP monitoring. Presence of intracranial hemorrhage and other injuries was also collected. Recording of patient management data included transfusions in the first 14 days, use of mannitol or hypertonic saline, therapeutic hypothermia, and administration of neuromuscular blockade. Length of hospital and ICU stay along with allcause mortality within 30 days was used as our primary endpoints. A database containing all previously admitted pediatric patients diagnosed from the desired time period was created. All patients with diagnosis codes of brain injury, traumatic cerebral edema, skull fractures, wounds to head, face, or scalp, and intracranial bleeding admitted to the PICU for more than 24 hours were included in the initial screening. Presented patient demographic and clinical data are expressed as the mean ± SD or median with interquartile range (IQR) dependent on data normality as assessed using the Shapiro-Wilk test ( < 0.05). Given the potential practice change of the publication of the landmark transfusion threshold study in critically ill children by Lacroix et al., we stratified the patients according to whether they were admitted prior to or after ( < 0.05) in continuous demographic and clinical variables between those transfused and not transfused were assessed using the independent samples -test or Mann Whitneytest upon failure of data normality. Significant differences ( < 0.05) in categorical variables were assessed using the chisquare test for association or Fisher's exact test. An exploratory model to predict the probability of mortality was developed using logistic regression. Seven independent variables (age, presence of suspected nonaccidental trauma (NAT), PRISM III score, RBC transnfusion, admission GCS score, admission Hgb, and 7-day mean Hgb) were initially considered as possible covariates. Prior to model construction, a correlation of = 0.65 was found between admission Hgb and 7-day mean Hgb using Spearman's rank coefficient. Univariate logistic regression was used to assess the strength of admission and 7-day mean Hgb in predicting the probability of mortality. Nagelkerke 2 values were 0.1 and 0.02 for admission and 7-day mean Hgb, respectively, supporting the consideration of admission Hgb as a covariate in our predictive logistic regression model. Additionally, an interaction term of RBC infusion * admission Hgb was also considered as a possible covariate. The criteria of variable selection for model inclusion followed that of Hosmer Jr. et al. Results A total of 466 patients with TBI were screened for possible study inclusion Canadian Respiratory Journal 3 The reduced covariate logistic regression model suspected NAT and PRISM III score as significant ( < 0.05) covariates: Log odds (mortality) = −5.294 + (2.198 * presence of suspected NAT) Odds ratios were 9.01 (95% CI: 2.16-37.68) and 1.32 (95% CI: 1.17-1.48) for presence of suspected NAT and PRISM III score, respectively. The model explained 55.2% of the variance in mortality (Nagelkerke 2 ) and correctly classified 89.1% of patients. Sensitivity and specificity were 50% and 97%, respectively. The likelihood ratio chi-square test was not significant ( 2 = 3.70; = 0.594). Discussion In this retrospective cohort study of 120 pediatric patients with severe TBI admitted to our PICU, it was found that hemoglobin at time of admission, administration of blood transfusions, and 7-day average hemoglobin after admission were not associated with adverse outcomes. Significant variables that were associated with increased mortality were the presence of suspected NAT and increasing PRISM score. It should be noted that there was a significant difference in the patients that were transfused and those that were not. The patients receiving blood transfusions tended to be younger and less well. Despite these differences, there was no clinical outcome difference associated with hemoglobin levels and transfusions. The goals of TBI management are to prevent secondary insults to the brain after the initial injury, including injury caused by hypoxia and hypotension In a large retrospective study of adult TBI patients, Salim and colleagues demonstrated that anemia and correction of it by blood transfusion are associated with increased mortality Similar to Sekhon and colleagues, we chose to study measured exposure to hemoglobin levels by looking at the initial and average hemoglobin for up to 7 days after admission. A variety of methods have been used to observe hemoglobin Canadian Respiratory Journal 5 levels, but 7 days is thought to capture the occurrence of peak ICP Other limitations of this study include the retrospective nature and the long period of time during which patient information was gathered. During this period of data collection, management strategies may have changed over time, which may have also affected our results. Having said that, our multivariate logistic regression analysis did not show an association between other management strategies and outcomes. All patients reviewed were admitted to a single centre suggesting that our results may not be entirely generalizable to other hospitals. However, the fact that our study found associations between NAT, GCS, and PRISM scores suggests that our study population is similar to other pediatric TBI studies that identified these as factors as well In conclusion, initial admission Hgb and mean Hgb values averaged over seven days after admission to PICU were not found to be strong predictors of mortality in children with severe TBI. No difference in outcome can be demonstrated when patients are transfused. Based on our study, we cannot advocate for deviation from the widely accepted transfusion threshold of 7 g per deciliter in critically ill pediatric patients presenting with TB
Second generation anticoagulant rodenticide residues in barn owls 2018
The current report is the fourth in a series of annual reports that describe the monitoring of second generation anticoagulant rodenticide (SGAR) liver residues in barn owls Tyto alba in
Britain. This work is an element of an overarching monitoring programme undertaken to track the outcomes of stewardship activities associated with the use of anticoagulant
rodenticides. The barn owl is used for exposure monitoring as it is considered a sentinel for species that are generalist predators of small mammals in rural areas. The specific work
reported here is the measurement of liver SGAR residues in 100 barn owls that died in 2018 in locations across Britain. The residue data are compared with those from 395 barn owls that
died between 2006 and 2012 (hereafter termed baseline years), prior to changes in anticoagulant rodenticide (AR) authorisations and onset of stewardship.
As in the baseline years, the compounds detected most frequently in barn owls that died in 2018 were bromadiolone, difenacoum and brodifacoum. Overall, 87% of the owls had
detectable liver residues of one or more SGAR.
The metrics to be used for stewardship monitoring are reported below in terms of differences between owls that died in 2018 and in baseline years.
Numbers of barn owls containing detectable residues of flocoumafen and difethialone. There was no significant difference in the proportion of barn owls with detectable liver residues of
flocoumafen between the baseline years and 2018. There was a significantly higher proportion of barn owls with detectable liver residues of difethialone in 2018 compared to baseline years (8% vs 0.3% ).
The ratio of birds with ”low” (100 ng/g wet wt.) concentrations for any single SGAR or for ∑SGARs. There was no significant difference between barn owls from
baseline years and from 2018 for any individual compound or for summed SGARs (∑SGARs), although a decrease in the proportion of birds with “high” difenacoum residues approached significance.
Average concentrations of brodifacoum, difenacoum, bromadiolone and ∑SGARs in the cohort of owls with “low” residues (100 ng/g ww). There was no significant difference between barn owls from baseline years and from 2018 in the concentrations of either “low” or “high” residues for bromadiolone, difenacoum (data tested statistically only for “low residues”), all residues summed (∑SGARs), or “high” brodifacoum residues. The median concentration of “low” brodifacoum residues was higher in birds from 2018 than in baseline years.
Overall, there were few differences in liver SGAR accumulation between barn owls that died in baseline years and in 2018. The lack of significant reductions in SGAR residues in barn owls in 2018 suggests that full implementation of stewardship since 2016 has yet to result in a reduction in exposure of barn owls to SGARs
The properties of extragalactic radio sources selected at 20 GHz
We present some first results on the variability, polarization and general
properties of radio sources selected in a blind survey at 20 GHz, the highest
frequency at which a sensitive radio survey has been carried out over a large
area of sky. Sources with flux densities above 100 mJy in the AT20G Pilot
Survey at declination -60 to -70 were observed at up to three epochs during
2002-4, including near-simultaneous measurements at 5, 8 and 18 GHz in 2003. Of
the 173 sources detected, 65% are candidate QSOs, BL Lac objects or blazars,
20% galaxies and 15% faint (b > 22 mag) optical objects or blank fields.
On a 1-2 year timescale, the general level of variability at 20 GHz appears
to be low. For the 108 sources with good-quality measurements in both 2003 and
2004, the median variability index at 20 GHz was 6.9% and only five sources
varied by more than 30% in flux density.
Most sources in our sample show low levels of linear polarization (typically
1-5%), with a median fractional polarization of 2.3% at 20 GHz. There is a
trend for fainter sources to show higher fractional polarization.
At least 40% of sources selected at 20GHz have strong spectral curvature over
the frequency range 1-20 GHz. We use a radio `two-colour diagram' to
characterize the radio spectra of our sample, and confirm that the radio-source
population at 20 GHz (which is also the foreground point-source population for
CMB anisotropy experiments like WMAP and Planck) cannot be reliably predicted
by extrapolating the results of surveys at lower frequencies. As a result,
direct selection at 20 GHz appears to be a more efficient way of identifying 90
GHz phase calibrators for ALMA than the currently-proposed technique of
extrapolation from all-sky surveys at 1-5 GHz.Comment: 14-page paper plus 5-page data table. Replaced with published versio
Second generation anticoagulant rodenticide residues in barn owls 2015
CEH contract report to the Campaign for Responsible Rodenticide Use (CRRU) UK
Characterizing psychosis risk traits in Africa: A longitudinal study of Kenyan adolescents
AbstractThe schizophrenia prodrome has not been extensively studied in Africa. Identification of prodromal behavioral symptoms holds promise for early intervention and prevention of disorder onset. Our goal was to investigate schizophrenia risk traits in Kenyan adolescents and identify predictors of psychosis progression.135 high-risk (HR) and 142 low-risk (LR) adolescents were identified from among secondary school students in Machakos, Kenya, using the structured interview of psychosis-risk syndromes (SIPS) and the Washington early recognition center affectivity and psychosis (WERCAP) screen. Clinical characteristics were compared across groups, and participants followed longitudinally over 0-, 4-, 7-, 14- and 20-months. Potential predictors of psychosis conversion and severity change were studied using multiple regression analyses.More psychiatric comorbidities and increased psychosocial stress were observed in HR compared to LR participants. HR participants also had worse attention and better abstraction. The psychosis conversion rate was 3.8%, with only disorganized communication severity at baseline predicting conversion (p=0.007). Decreasing psychotic symptom severity over the study period was observed in both HR and LR participants. ADHD, bipolar disorder, and major depression diagnoses, as well as poor occupational functioning and avolition were factors relating to lesser improvement in psychosis severity.Our results indicate that psychopathology and disability occur at relatively high rates in Kenyan HR adolescents. Few psychosis conversions may reflect an inadequate time to conversion, warranting longer follow-up studies to clarify risk predictors. Identifying disorganized communication and other risk factors could be useful for developing preventive strategies for HR youth in Kenya
Second generation anticoagulant rodenticide residues in barn owls 2016
CEH contract report to the Campaign for Responsible Rodenticide Use (CRRU) UK
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Digital Trajectories to Care in First-Episode Psychosis.
OBJECTIVE::The emphasis on reducing the duration of untreated psychosis (DUP) has highlighted complex barriers to accessing appropriate services. Internet and social media use by individuals with first-episode psychosis (FEP) was examined to explore how these platforms might be used to facilitate treatment initiation. METHODS::Participants ages 15-35 were interviewed with the Pathways to Care for Psychosis Questionnaire, an 81-item instrument designed to explore online activity during symptom emergence. RESULTS::Of 112 participants, 90% used the Internet and social media daily. The Internet was listed as the most used resource (62%) for information while symptoms were emerging. A minority (19%) shared concerns via social media, and 76% responded favorably to the possibility of receiving online mental health support. CONCLUSIONS::The Internet and social media were part of daily life for participants with FEP. Activity continued throughout the DUP, offering the prospect of earlier intervention. Participants expressed positive attitudes toward Internet-based outreach and engagement efforts
Assessing gender mainstreaming in the education sector: depoliticised technique or a step towards women's rights and gender equality?
In 1995 the Beijing Conference on Women identified gender mainstreaming as a key area for action. Policies to effect gender mainstreaming have since been widely adopted. This special issue of Compare looks at research on how gender mainstreaming has been used in government education departments, schools, higher education institutions, international agencies and NGOs .1 In this introduction we first provide a brief history of the emergence of gender mainstreaming and review changing definitions of the term. In the process we outline some policy initiatives that have attempted to mainstream gender and consider some difficulties with putting ideas into practice, particularly the tensions between a technical and transformative interpretations . Much of the literature about experiences with gender mainstreaming tends to look at organizational processes and not any specificities of a particular social sector. However, in our second section, we are concerned to explore whether institutional forms and particular actions associated with education give gender mainstreaming in education sites some distinctive features. In our last section we consider some of the debates about global and local negotiations in discussions of gender policy and education and the light this throws on gender mainstreaming. In so doing, we place the articles that follow in relation to contestations over ownership, political economy, the form and content of education practice and the social complexity of gender equality
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