52 research outputs found
Spectrum and Morphology of the Two Brightest Milagro Sources in the Cygnus Region: MGRO J2019+37 and MGRO J2031+41
The Cygnus region is a very bright and complex portion of the TeV sky, host
to unidentified sources and a diffuse excess with respect to conventional
cosmic-ray propagation models. Two of the brightest TeV sources, MGRO J2019+37
and MGRO J2031+41, are analyzed using Milagro data with a new technique, and
their emission is tested under two different spectral assumptions: a power law
and a power law with an exponential cutoff. The new analysis technique is based
on an energy estimator that uses the fraction of photomultiplier tubes in the
observatory that detect the extensive air shower. The photon spectrum is
measured in the range 1 to 200 TeV using the last 3 years of Milagro data
(2005-2008), with the detector in its final configuration. MGRO J2019+37 is
detected with a significance of 12.3 standard deviations (), and is
better fit by a power law with an exponential cutoff than by a simple power
law, with a probability % (F-test). The best-fitting parameters for the
power law with exponential cutoff model are a normalization at 10 TeV of
, a spectral
index of and a cutoff energy of TeV. MGRO
J2031+41 is detected with a significance of 7.3, with no evidence of a
cutoff. The best-fitting parameters for a power law are a normalization of
and a
spectral index of . The overall flux is subject to an
30% systematic uncertainty. The systematic uncertainty on the power law
indices is 0.1. A comparison with previous results from TeV J2032+4130,
MGRO J2031+41 and MGRO J2019+37 is also presented.Comment: 11 pages, 10 figure
Observation and Spectral Measurements of the Crab Nebula with Milagro
The Crab Nebula was detected with the Milagro experiment at a statistical
significance of 17 standard deviations over the lifetime of the experiment. The
experiment was sensitive to approximately 100 GeV - 100 TeV gamma ray air
showers by observing the particle footprint reaching the ground. The fraction
of detectors recording signals from photons at the ground is a suitable proxy
for the energy of the primary particle and has been used to measure the photon
energy spectrum of the Crab Nebula between ~1 and ~100 TeV. The TeV emission is
believed to be caused by inverse-Compton up-scattering scattering of ambient
photons by an energetic electron population. The location of a TeV steepening
or cutoff in the energy spectrum reveals important details about the underlying
electron population. We describe the experiment and the technique for
distinguishing gamma-ray events from the much more-abundant hadronic events. We
describe the calculation of the significance of the excess from the Crab and
how the energy spectrum is fit. The fit is consistent with values measured by
IACTs between 1 and 20 TeV. Fixing the spectral index to values that have been
measured below 1 TeV by IACT experiments (2.4 to 2.6), the fit to the Milagro
data suggests that Crab exhibits a spectral steepening or cutoff between about
20 to 40 TeV.Comment: Submitted to Astrophysical Journa
Global variability in leaf respiration in relation to climate, plant functional types and leaf traits
• Leaf dark respiration (Rdark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdark and associated leaf traits.
• Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed-effects models were used to disentangle sources of variation in Rdark.
• Area-based Rdark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8–28°C). By contrast, Rdark at a standard T (25°C, Rdark25) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher Rdark25 at a given photosynthetic capacity (Vcmax25) or leaf nitrogen concentration ([N]) than species at warmer sites. Rdark25 values at any given Vcmax25 or [N] were higher in herbs than in woody plants.
• The results highlight variation in Rdark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of Rdark in terrestrial biosphere models (TBMs) and associated land-surface components of Earth system models (ESMs)
Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
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Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
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Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
The original version of this article unfortunately contained a mistake
Fenestrated endovascular aneurysm repair and open surgical repair for the treatment of juxtarenal aortic aneurysms
International audienceOBJECTIVE:The objective of this study was to compare surgical risk and early and late mortality of patients treated for anatomically classified juxtarenal aortic aneurysms (JRAs) by fenestrated endovascular aneurysm repair (F-EVAR) or open surgical repair (OSR) during a period when the two treatments were available and to validate an institutional algorithm for JRA repair.METHODS:We retrospectively included all patients treated electively in our center between January 2005 and December 2015 for JRAs classified into three anatomic categories, excluding suprarenal aneurysms. Lee score and American Society of Anesthesiologists (ASA) class evaluated preoperative surgical risk. We compared clinical and radiologic parameters between the patients treated by F-EVAR and those treated by OSR. The primary study end point was 30-day mortality. We also compared 5-year survival.RESULTS:From 2005 to 2015, there were 191 patients separated into two groups, one treated by OSR (n = 134; mean age, 69 years) and the other treated by F-EVAR (n = 57; mean age, 74 years). Patients of the F-EVAR group were significantly older (P = .001). Intensive care unit length of stay was significantly higher in the OSR group (3.4 days vs 1.5 days; P = .01). Surgical risk was significantly higher in the F-EVAR group as measured by Lee score ≥2 (OSR, 8.9 %; F-EVAR, 21%; P = .02) and ASA class 3 and class 4 (OSR, 32.8%; F-EVAR, 73.6%; P = .001), whereas 30-day postoperative mortality was not significantly different (OSR, 1.5%; F-EVAR, 0%; P = .394). The 5-year survival was not significantly different in the two groups (OSR, 82.1%; F-EVAR, 69.2%).CONCLUSIONS:In this study, despite a higher surgical risk by Lee score and higher ASA class in the group of patients treated by F-EVAR, postoperative mortality was not significantly different between these groups. In our opinion, F-EVAR and OSR of JRA are complementary
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Temporal Dynamics of Human Frontal and Cingulate Neural Activity During Conflict and Cognitive Control
Cognitive control refers to the ability to produce flexible, goal-oriented behavior in the face of changing task demands and conflicting response tendencies. A classic cognitive control experiment is the Stroop-color naming task, which requires participants to name the color in which a word is written while inhibiting the tendency to read the word. By comparing stimuli with conflicting word-color associations to congruent ones, control processes over response tendencies can be isolated. We assessed the spatial specificity and temporal dynamics in the theta and gamma bands for regions engaged in detecting and resolving conflict in a cohort of 13 patients using a combination of high-resolution surface and depth recordings. We show that cognitive control manifests as a sustained increase in gamma band power, which correlates with response time. Conflict elicits a sustained gamma power increase but a transient theta power increase, specifically localized to the left cingulate sulcus and bilateral dorsolateral prefrontal cortex (DLPFC). Additionally, activity in DLPFC is affected by trial-by-trial modulation of cognitive control (the Gratton effect). Altogether, the sustained local neural activity in dorsolateral and medial regions is what determines the timing of the correct response
The moderating role of caregiver preparedness on the relationship between depression and stroke-specific quality of life in stroke dyads: a longitudinal study
Aims To examine the moderating role of caregiver preparedness on the association between stroke survivors' depression and stroke-specific quality of life dimensions. Methods and results We used a multilevel modelling approach to analyse trajectories of change in the eight Stroke Impact Scale 3.0 subscales [i.e. strength, communication, mobility, activities of daily living (ADL)/instrumental activities of daily living (IADL), memory, emotion, hand function, participation] using Hierarchical Linear Modeling. Caregiver preparedness significantly moderated the association between survivor depressive symptoms and survivor communication (B = -0.95, P < 0.01), mobility (B = -0.60, P < 0.05), and ADL/IADL (B = -0.73, P < 0.01) at baseline; linear change for strength (B = 0.83, P < 0.05) and communication (B = 0.66, P < 0.05); and quadratic change for strength (B = -0.19, P < 0.01). Although caregiver preparedness did not significantly moderate the association between survivor depressive symptoms and strength at baseline, there was a significant moderating effect for change over time. Higher levels of caregiver preparedness were significantly associated with higher survivor scores of emotion, hand function, and participation at baseline. Conclusions Including immediate caregivers in the care process, through a psycho-educational training, would mean having better-prepared caregivers and consequently more-healthy stroke survivors. Given that preparedness includes coping with stress, responding and managing emergencies, assessing help and information may require tailored interventions aimed at improving the caregivers' skills and knowledge about stroke survivors' management
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