2,463 research outputs found
A Process–Based Rating Curve to model suspended sediment concentration in Alpine environments
A Process-Based Rating Curve (PBRC) approach to simulate mean daily suspended sediment concentration (SSC) as a function of different sediment sources and their activation by erosive rainfall (ER), snowmelt (SM), and icemelt (IM) in an Alpine catchment is presented. Similarly to the traditional rating curve, the PBRC relates SSC to the three main hydroclimatic variables through power functions. We obtained the hydroclimatic variables from daily gridded datasets of precipitation and temperature, implementing a degree-day model to simulate spatially distributed snow accumulation and snow-ice melt. We calibrated the PBRC parameters by an Iterative Input Selection algorithm to capture the characteristic response time lags, and by a gradient-based nonlinear optimization method to minimize the errors between SSC observations and simulations. We apply our approach in the upper Rhône Basin, a large Alpine catchment in Switzerland. Results show that all three hydroclimatic processes ER, SM, and IM are significant predictors of mean daily SSC (explaining 75 %, 12 % and 3 % of the total observed variance). Despite not using discharge in prediction, the PBRC performs better than the traditional rating curve, especially during validation at the daily scale and in reproducing SSC seasonality. The characteristic time lags of the three variables in contributing to SSC reflect the typical flow concentration times of the corresponding hydrological processes in the basin. Erosive rainfall determines the daily variability of SSC, icemelt generates the highest SSC per unit of runoff, and snowmelt-driven fluxes represent the largest contribution to total suspended sediment yield. Finally, we show that the PBRC is able to simulate changes in SSC in the past 40 years in the Rhône Basin connected to air temperature rise, even though these changes are more gradual than those detected in observations. We argue that a sediment source perspective on suspended sediment transport such as the PBRC may be more suitable than traditional discharge-based rating curves to explore climate-driven changes in fine sediment dynamics in Alpine catchments. The PBRC approach can be applied to any Alpine catchment with a pluvio-glacio-nival hydrological regime and adequate hydroclimatic datasets.ISSN:1812-2116ISSN:1812-210
Closing the Osteoporosis Care Gap in Hip Fracture Patients: An Opportunity to Decrease Recurrent Fractures and Hospital Admissions
Background. Falls and hip fractures are an increasing health threat to older people who often never return to independent living. This study examines the management of bone health in an acute care setting following a hip fracture in patients over age 65. Methods. Retrospective chart review of all patients admitted to a tertiary health facility who suffered a recent hip fracture. Results. 420 charts of patients admitted over the course of a year (May 1, 2007–April 31, 2008) were reviewed. Thirty-seven percent of patients were supplemented with calcium on discharge, and 36% were supplemented with vitamin D on discharge. Thirty-one percent were discharged on a bisphosphonate. Conclusion. A significant care gap still exists in how osteoporosis is addressed despite guidelines on optimal management. A call to action is required by use of multifaceted approaches to bridge the gap, ensuring that fracture risk is minimized for the aging population
Quantifying the Clinical Significance of Cannabis Withdrawal
Background and Aims:
Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt.
Methods and Results:
A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p = 0.0001). Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p = 0.03). Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p = 0.001).
Conclusions:
Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes
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We Need Better Education Policy. Summit Public Schools Shows Why.
Summit Public Schools (SPS), a California-based charter school network established in 2003, is widely promoted nationally as a success story to be emulated. A policy environment friendly to charter schools and digital technologies, together with hundreds of millions of dollars in technology industry contributions, enabled its growth and its national visibility. Because of SPS’s boasts of success and its national prominence, understanding its story is a useful way to gain insight into how Silicon Valley funds and markets education initiatives. It also reveals inadequacies in policy related to school performance, digital educational programs, protection of student data, and school funding. This research brief analyzes the documents SPS provided in response to a request for public records bearing on its reports of students’ academic success, its curriculum and instruction program, its proprietary digital platform, its protection of student data, its funding, and the validity and reliability of its assessments. In its discussion of documents both provided and not provided, the authors illustrate how SPS serves as an example of how nominally nonprofit charter school organizations evade public oversight and provide technology companies and their investors with both a market for their products and a continually renewing source of valuable data from young people.</p
Quantifying the Clinical Significance of Cannabis Withdrawal
Background and Aims: Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt. Methods and Results: A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p = 0.0001). Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p = 0.03). Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p = 0.001). Conclusions: Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes. © 2012 Allsop et al
Inhalation health risk assessment of ambient PM2.5 and associated trace elements in Cape Town, South Africa
This manuscript was part of the Ph.D. project of Anna Alfeus. Prof Janine Wichmann and Dr. Joyce Shirinde supervised the Ph.D. thesis.DATA AVAILABILITY : The authors are working on other manuscripts with the data, hence the data is not available to the public.Please read abstract in article.The University of Pretoria doctoral bursary, University of Namibia Staff Development office, the AGNES grant office and analysis funding with an NRF grant.https://www.tandfonline.com/loi/bher20hj2023School of Health Systems and Public Health (SHSPH
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Background. Falls and hip fractures are an increasing health threat to older people who often never return to independent living. This study examines the management of bone health in an acute care setting following a hip fracture in patients over age 65. Methods. Retrospective chart review of all patients admitted to a tertiary health facility who suffered a recent hip fracture. Results. 420 charts of patients admitted over the course of a year (May 1, 2007-April 31, 2008 were reviewed. Thirty-seven percent of patients were supplemented with calcium on discharge, and 36% were supplemented with vitamin D on discharge. Thirty-one percent were discharged on a bisphosphonate. Conclusion. A significant care gap still exists in how osteoporosis is addressed despite guidelines on optimal management. A call to action is required by use of multifaceted approaches to bridge the gap, ensuring that fracture risk is minimized for the aging population
Contribution of the HMPID detector to the high-pT physics at LHC
The LHC will deliver unexplored energy regimes for proton-proton and
heavy-ion collisions. As shown by the RHIC experiments, particle identification
over a large momentum range is essential to disentangle physics processes,
especially in the intermediate p (1 GeV/c) region. The novel
design of the High-Momentum Particle Identification Detector (HMPID), based on
large surface CsI photocathodes, is able to identify , ,
and in the momentum region where bulk medium properties and hard
scatterings interplay. Furthermore, measurement of resonance particles such as
the could provide information on the system evolution. The
HMPID layout and segmentation are optimized to study particle correlations at
high momenta describing the early phase and the dynamical evolution of the
collision. At LHC, the increased hard cross section will significantly be
enhanced compared to RHIC. Jet reconstruction via Deterministic Annealing can
address jet quenching and detailed measurements of jet properties. In this
paper, we present these selected topics from the possible HMPID contributions
to the physics goals of LHC.Comment: 6 pages, 7 figures, Contribution to QCD @ Work 2007: International
Workshop on Quantum Chromodynamics Theory and Experiment, Martina Franca,
Italy, 16-20 June 200
Non-canonical role for Lpar1-EGFP subplate neurons in early postnatal mouse somatosensory cortex
Subplate neurons (SPNs) are thought to play a role in nascent sensory processing in neocortex. To better understand how heterogeneity within this population relates to emergent function, we investigated the synaptic connectivity of Lpar1-EGFP SPNs through the first postnatal week in whisker somatosensory cortex (S1BF). These SPNs comprise of two morphological subtypes: fusiform SPNs with local axons and pyramidal SPNs with axons that extend through the marginal zone. The former receive translaminar synaptic input up until the emergence of the whisker barrels, a timepoint coincident with significant cell death. In contrast, pyramidal SPNs receive local input from the subplate at early ages but then – during the later time window – acquire input from overlying cortex. Combined electrical and optogenetic activation of thalamic afferents identified that Lpar1-EGFP SPNs receive sparse thalamic innervation. These data reveal components of the postnatal network that interpret sparse thalamic input to direct the emergent columnar structure of S1BF
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