Inter-model variability and biases of the global water cycle in CMIP3 coupled climate models

Observed changes such as increasing global temperatures and the intensification of the global water cycle in the 20th century are robust results of coupled general circulation models (CGCMs). In spite of these successes, model-to-model variability and biases that are small in first order climate responses, however, have considerable implications for climate predictability especially when multi-model means are used. We show that most climate simulations of the 20th and 21st century A2 scenario performed with CMIP3 (Coupled Model Inter-comparison Project Phase 3) models have deficiencies in simulating the global atmospheric moisture balance. Large biases of only a few models (some biases reach the simulated global precipitation changes in the 20th and 21st centuries) affect the multi-model mean global moisture budget. An imbalanced flux of -0.14 Sv exists while the multi-model median imbalance is only -0.02 Sv. Moreover, for most models the detected imbalance changes over time. As a consequence, in 13 of the 18 CMIP3 models examined, global annual mean precipitation exceeds global evaporation, indicating that there should be a 'leaking' of moisture from the atmosphere whereas for the remaining five models a 'flooding' is implied. Nonetheless, in all models, the actual atmospheric moisture content and its variability correctly increases during the course of the 20th and 21st centuries. These discrepancies therefore imply an unphysical and hence 'ghost' sink/source of atmospheric moisture in the models whose atmospheres flood/leak. The ghost source/sink of moisture can also be regarded as atmospheric latent heating/cooling and hence as positive/negative perturbation of the atmospheric energy budget or non-radiative forcing in the range of -1 to +6 W m^-2 (median +0.1 W m^-2). The inter-model variability of the global atmospheric moisture transport from oceans to land areas, which impacts the terrestrial water cycle, is also quite high and ranges from 0.26 to 1.78 Sv. In the 21st century this transport to land increases by about 5% per century with a model-to-model range from 1 to 13%. We suggest that this variability is weakly correlated to the land-sea contrast in air temperature change of these models. Spatially heterogeneous forcings such as aerosols contribute to the variability in moisture transport, at least in one model. The polewards shifts of dry zones in climate simulations of the 21st century are also assessed. It is shown that the multi-model means of the two subsets of models with negative and positive imbalances in the atmospheric moisture budget produce spatial variability in the dry zone positions similar in size to the spatial shifts expected from 21st century global warming. Thus, the selection of models also affects the multi-model mean dry zone extension. In general, we caution the use of multi-model means of E - P fields and suggest self-consistency tests for climate models

Perceived Facilitators and Barriers to Physical Activity for Rural Youth: An Exploratory Study using Photovoice

Introduction: Decreasing physical activity levels, particularly among youth, continue to be a prominent health concern in Canada, and youth living in rural areas may encounter unique facilitators and barriers to physical activity. In addition, current research suggests that overweight and obesity rates are higher for youth in some rural areas compared with urban areas. The goal of this study was to identify the perceived facilitators and barriers to physical activity for a selected sample of rural youth at a rural secondary school in south-western Ontario and examine how rural barriers and facilitators affect rural youth physical activity. Current Canadian literature addresses rural youth physical activity in a very limited fashion. Thus, the goal of this research was to provide important insights into physical activity for rural youth. Method: Nine participants aged 13 to 18 years completed the study using the photovoice methodology and method. Photovoice is a relatively new method for health research that adopts an innovative approach whereby participants use cameras to document their perceived health realities. In photovoice the images and words from the life experiences of participants create the basis for discussion. Participants had 2 weeks to take photographs. After 2 weeks the cameras and logbooks were retrieved, the photographs were developed, and a one-on-one interview was held with each participant. The interviews focused on participants’ explanations of their photographs and their relevance to physical activity. Results: Analysis of the pictorial, narrative, and logbook data provided by participants revealed 12 themes as facilitators and barriers to physical activity. Some of the themes relate to facilitators (eg early exposure to activities), some to barriers (eg lack of opportunities close to home), and some themes represent both a facilitator and a barrier (eg competitiveness, family support, and peer interests). The findings of this study may assist community stakeholders, school officials, and parents to better support the physical activity needs of rural youth. Conclusions: Physical activity rates continue to decline and to be a major health concern for Canadian youth. Thus, it is becoming increasingly important to understand physical activity from the perspective of rural youth. Implications of this information for rural communities, rural schools, and rural residents are significant. These implications and recommendations may help facilitate increased participation in physical activity for rural youth by providing them, and their families and communities, with enhanced opportunities and resources to engage in physical activity. Further research is clearly indicated

Corticomotor excitability during precision motor tasks

The aim of this preliminary study was to investigate motor cortex (cortical) excitability between a similar fine visuomotor task of varying difficulty. Ten healthy adults (three female, seven male; 20—45 years of age) participated in the study. Participants were instructed to perform a fine visuomotor task by statically abducting their first index finger against a force transducer which displayed the level of force (represented as a marker) on a computer monitor. This marker was to be maintained between two stationary bars, also displayed on the computer monitor. The level of difficulty was increased by amplifying the position of the marker, making the task more difficult to control. Cortical measures of motor evoked potential (MEP) and silent period (SP) duration in first dorsal interosseous (FDI) muscle were obtained using transcranial magnetic stimulation (TMS) while the participant maintained the ‘‘easy’’ or ‘‘difficult’’ static task. An 11.8% increase in MEP amplitude was observed when subjects undertook the ‘‘difficult’’ task, but no differences in MEP latency or SP duration. The results from this preliminary study suggest that cortical excitability increases reflect the demand required to perform tasks requiring greater precision with suggestions for further research discussed

Einflussfaktoren und Prädiktoren von Stürzen bei degenerativer Ataxie

Patienten mit Ataxie weisen eine erhöhte Sturzneigung auf. Aufgrund der individuellen verletzungsbedingten und der sozio-ökonomischen Konsequenzen ist es notwendig, Stürze zu vermeiden. Ein wesentlicher Schritt ist die Identifizierung von möglichen Sturzursachen. Ziel dieser Arbeit war es, durch umfangreiche komplementäre Untersuchungen prospektive Sturzprädiktoren von Patienten mit Ataxie zu detektieren. Es wurden 39 Patienten analysiert, von denen 30 Patienten eine cerebelläre Ataxie und neun Patienten eine afferente Ataxie aufwiesen. Es wurden Gangparameter (Schrittanzahl/180°-Drehung, Zeit/180°-Drehung, Schrittanzahl/Minute) in einer Ganganalyse erhoben. Zusätzlich erfolgte eine klinische Datenerhebung von Ataxie-spezifischen (SARA) und Nicht-Ataxie-spezifischen Assessments (MoCA, FES-I, DGI, LLFDI SPPB, ADS). Die prospektive erfasste Sturzanzahl innerhalb von sechs Monaten wurde mittels Korrelationsanalysen, linearer Regressionsanalyse sowie schrittweiser, multipler Regressionsanalyse mit den erhobenen Daten in Beziehung gesetzt. Die Ergebnisse zeigen, dass die Sturzhäufigkeit mit der SARA, SPPB, Schrittanzahl/180°-Drehung sowie Zeit/180°-Drehung signifikant korreliert. Sowohl in der linearen Regression als auch der schrittweisen, multiplen Regression erwiesen sich Schrittanzahl/180°-Drehung, ADS und SARA als die wichtigsten Sturzprädiktoren. Im Rahmen einer „Dual Task“-Aufgabe (schnelles Gehen + graphomotorische Übung) verschlechterten sich die Gangparameterleistungen signifikant verglichen mit der „Single Task“-Aufgabe (Schnelles Gehen). Somit scheinen Ataxie-Patienten insbesondere durch die Kombination zweier motorischer Aufgaben eine stärkere Leistungseinschränkung zu zeigen. In weiteren Studien sollten die hier gefundenen Ergebnisse an einer größeren Stichprobe bestätigt und hinsichtlich möglicher „Cut off“-Werte untersucht werden

Using the Flexor Reflex in a Chronic Stroke Patient for Gait Improvement: A Case Report

The flexor reflex or withdrawal reflex can be elicited by electrical stimulation of the sole of the foot, which serves as a reflex to protect the stimulated limb against tissue damage and consists of flexion movements in the hip, knee, and ankle joint. Triggering this reflex might improve walking abilities in hemiparetic patients. We report the first case of a chronic stroke patient with the most severe impairment of walking. She was examined with and without flexor reflex activation by the Incedo® system. Tests included a 10-m walk and a 2-min walk at baseline, after 3 weeks of training with the Incedo® system and after a follow-up 3 weeks later. Moreover, a kinematic gait analysis was done before and after the training period. At baseline, activation of the flexor reflex induced an improved gait velocity. After the training period, the patient walked twice as fast compared with baseline. Her gait velocity without Incedo® was faster than the gait velocity with Incedo® at baseline. Examination at follow-up indicated that the improvements remained almost unchanged. The kinematic analysis showed an improved stride length and gait velocity during flexor reflex activation. Initially, the foot was elevated higher above the ground during flexor reflex activation. In conclusion, this first case report of a chronic stroke patient demonstrates that flexor reflex activation is feasible and improves gait parameters despite severe impairment of walking abilities

Future changes in atmospheric rivers and their implications for winter flooding in Britain

Within the warm conveyor belt of extra-tropical cyclones, atmospheric rivers (ARs) are the key synoptic features which deliver the majority of poleward water vapour transport, and are associated with episodes of heavy and prolonged rainfall. ARs are responsible for many of the largest winter floods in the mid-latitudes resulting in major socioeconomic losses; for example, the loss from United Kingdom (UK) flooding in summer/winter 2012 is estimated to be about $1.6 billion in damages. Given the well-established link between ARs and peak river flows for the present day, assessing how ARs could respond under future climate projections is of importance in gauging future impacts from flooding. We show that North Atlantic ARs are projected to become stronger and more numerous in the future scenarios of multiple simulations from five state-of-the-art global climate models (GCMs) in the fifth Climate Model Intercomparison Project (CMIP5). The increased water vapour transport in projected ARs implies a greater risk of higher rainfall totals and therefore larger winter floods in Britain, with increased AR frequency leading to more flood episodes. In the high emissions scenario (RCP8.5) for 2074–2099 there is an approximate doubling of AR frequency in the five GCMs. Our results suggest that the projected change in ARs is predominantly a thermodynamic response to warming resulting from anthropogenic radiative forcing

Cortical thickness changes in the non-lesioned hemisphere associated with non-paretic arm immobilization in modified CI therapy

Recent evidence suggests that immobilization of the upper limb for 2–3 weeks induces changes in cortical thickness as well as motor performance. In constraint induced (CI) therapy, one of the most effective interventions for hemiplegia, the non-paretic arm is constrained to enforce the use of the paretic arm in the home setting. With the present study we aimed to explore whether non-paretic arm immobilization in CI therapy induces structural changes in the non-lesioned hemisphere, and how these changes are related to treatment benefit. 31 patients with chronic hemiparesis participated in CI therapy with (N = 14) and without (N = 17) constraint. Motor ability scores were acquired before and after treatment. Diffusion tensor imaging (DTI) data was obtained prior to treatment. Cortical thickness was measured with the Freesurfer software. In both groups cortical thickness in the contralesional primary somatosensory cortex increased and motor function improved with the intervention. However the cortical thickness change was not associated with the magnitude of motor function improvement. Moreover, the treatment effect and the cortical thickness change were not significantly different between the constraint and the non-constraint groups. There was no correlation between fractional anisotropy changes in the non-lesioned hemisphere and treatment outcome. CI therapy induced cortical thickness changes in contralesional sensorimotor regions, but this effect does not appear to be driven by the immobilization of the non-paretic arm, as indicated by the absence of differences between the constraint and the non-constraint groups. Our data does not suggest that the arm immobilization used in CI therapy is associated with noticeable cortical thinning

An Efficient Implementation of Parallelization in the Domain Decomposition of TELEMAC

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