104 research outputs found
Which executive functioning deficits are associated with AD/HD, ODD/CD and comorbid AD/HD+ODD/CD?
Item does not contain fulltextThis study investigated (1) whether attention deficit/hyperactivity disorder (AD/HD) is associated with executive functioning (EF) deficits while controlling for oppositional defiant disorder/conduct disorder (ODD/CD), (2) whether ODD/CD is associated with EF deficits while controlling for AD/HD, and (3)~whether a combination of AD/HD and ODD/CD is associated with EF deficits (and the possibility that there is no association between EF deficits and AD/HD or ODD/CD in isolation). Subjects were 99~children ages 6â12 years. Three putative domains of EF were investigated using well-validated tests: verbal fluency, working memory, and planning. Independent of ODD/CD, AD/HD was associated with deficits in planning and working memory, but not in verbal fluency. Only teacher rated AD/HD, but not parent rated AD/HD, significantly contributed to the prediction of EF task performance. No EF deficits were associated with ODD/CD. The presence of comorbid AD/HD accounts for the EF deficits in children with comorbid AD/HD+ODD/CD. These results suggest that EF deficits are unique to AD/HD and support the model proposed by R. A. Barkley (1997).17 p
Executive functions in preschool children with aggressive behavior: impairments in inhibitory control
The question whether executive function (EF)
deficits in children are associated with conduct problems
remains controversial. Although the origins of aggressive
behavior are to be found in early childhood, findings from
EF studies in preschool children with aggressive behavior
are inconsistent. The current study aimed to investigate
whether preschool children with aggressive behavior show
impairments in EF. From a population-based sample, 82
preschool children who were showing aggressive behavior
as indicated by scores at or above the 93rd percentile on the
Aggressive Behavior Scale of the CBCL 1 1/2-5 were
selected. These children with aggressive behavior were
matched on IQ to a group of typically developing control
children (N=99). Six neuropsychological tasks were administered
to assess set shifting, inhibition, working memory
and verbal fluency. A factor analysis was conducted which
yielded one clear factor: inhibition. Aggressive preschool children showed poorer performance on this inhibition
factor than control children and boys performed worse on
this factor than girls. This association between aggressive
behavior and inhibition deficits was maintained after controlling
for attention problems. In addition, gender differences
in all EFs measured were found with boys exhibiting
more impairment in EF than girls. These findings demonstrate
that preschool children with aggressive behavior show
impairments in inhibition, irrespective of attention problems
The processing and impact of dissolved riverine nitrogen in the Arctic Ocean
© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Estuaries and Coasts 35 (2012): 401-415, doi:10.1007/s12237-011-9417-3.Although the Arctic Ocean is the most riverine-influenced of all of the worldâs oceans, the importance of terrigenous nutrients in this environment is poorly understood. This study couples estimates of circumpolar riverine nutrient fluxes from the PARTNERS (Pan-Arctic River Transport of Nutrients, Organic Matter, and Suspended Sediments) Project with a regionally configured version of the MIT general circulation model to develop estimates of the distribution and availability of dissolved riverine N in the Arctic Ocean, assess its importance for primary production, and compare these estimates to potential bacterial production fueled by riverine C. Because riverine dissolved organic nitrogen is remineralized slowly, riverine N is available for uptake well into the open ocean. Despite this, we estimate that even when recycling is considered, riverine N may support 0.5â1.5 Tmol C yearâ1 of primary production, a small proportion of total Arctic Ocean photosynthesis. Rapid uptake of dissolved inorganic nitrogen coupled with relatively high rates of dissolved organic nitrogen regeneration in N-limited nearshore regions, however, leads to potential localized rates of riverine-supported photosynthesis that represent a substantial proportion of nearshore production.Funding for this work was provided through NSFOPP-
0229302 and NSF-OPP-0732985.Support to SET was additionally
provided by an NSERC Postdoctoral Fellowship
Re-evaluation of blood mercury, lead and cadmium concentrations in the Inuit population of Nunavik (Québec): a cross-sectional study
<p>Abstract</p> <p>Background</p> <p>Arctic populations are exposed to mercury, lead and cadmium through their traditional diet. Studies have however shown that cadmium exposure is most often attributable to tobacco smoking. The aim of this study is to examine the trends in mercury, lead and cadmium exposure between 1992 and 2004 in the Inuit population of Nunavik (Northern QuĂ©bec, Canada) using the data obtained from two broad scale health surveys, and to identify sources of exposure in 2004.</p> <p>Methods</p> <p>In 2004, 917 adults aged between 18 and 74 were recruited in the 14 communities of Nunavik to participate to a broad scale health survey. Blood samples were collected and analysed for metals by inductively coupled plasma mass spectrometry, and dietary and life-style characteristics were documented by questionnaires. Results were compared with data obtained in 1992, where 492 people were recruited for a similar survey in the same population.</p> <p>Results</p> <p>Mean blood concentration of mercury was 51.2 nmol/L, which represent a 32% decrease (p < 0.001) between 1992 and 2004. Mercury blood concentrations were mainly explained by age (partial r<sup>2 </sup>= 0.20; p < 0.0001), and the most important source of exposure to mercury was marine mammal meat consumption (partial r<sup>2 </sup>= 0.04; p < 0.0001). In 2004, mean blood concentration of lead was 0.19 ÎŒmol/L and showed a 55% decrease since 1992. No strong associations were observed with any dietary source, and lead concentrations were mainly explained by age (partial r<sup>2 </sup>= 0.20.; p < 0.001). Blood cadmium concentrations showed a 22% decrease (p < 0.001) between 1992 and 2004. Once stratified according to tobacco use, means varied between 5.3 nmol/L in never-smokers and 40.4 nmol/L in smokers. Blood cadmium concentrations were mainly associated with tobacco smoking (partial r<sup>2 </sup>= 0.56; p < 0.0001), while consumption of caribou liver and kidney remain a minor source of cadmium exposure among never-smokers.</p> <p>Conclusion</p> <p>Important decreases in mercury, lead and cadmium exposure were observed. Mercury decrease could be explained by dietary changes and the ban of lead cartridges use likely contributed to the decrease in lead exposure. Blood cadmium concentrations remain high and, underscoring the need for intensive tobacco smoking prevention campaigns in the Nunavik population.</p
Multiple uses of fibrin sealant for nervous system treatment following injury and disease
TRĂS DĂCADAS DE PESQUISA EM EMPREENDEDORISMO: UMA REVISĂO DOS PRINCIPAIS PERIĂDICOS INTERNACIONAIS DE EMPREENDEDORISMO
Tryptase is involved in the development of early ventilator-induced pulmonary fibrosis in sepsis-induced lung injury
A synthesis of the arctic terrestrial and marine carbon cycles under pressure from a dwindling cryosphere
Evaluating uncertainties in modelling the snow hydrology of the Fraser River Basin, British Columbia, Canada
This study evaluates predictive uncertainties in the snow hydrology of the
Fraser River Basin (FRB) of British Columbia (BC), Canada, using the Variable
Infiltration Capacity (VIC) model forced with several high-resolution gridded
climate datasets. These datasets include the Canadian Precipitation Analysis
and the thin-plate smoothing splines (ANUSPLIN), North American Regional
Reanalysis (NARR), University of Washington (UW) and Pacific Climate Impacts
Consortium (PCIC) gridded products. Uncertainties are evaluated at different
stages of the VIC implementation, starting with the driving datasets,
optimization of model parameters, and model calibration during cool and warm
phases of the Pacific Decadal Oscillation (PDO).
The inter-comparison of the forcing datasets (precipitation and air
temperature) and their VIC simulations (snow water equivalent – SWE – and runoff) reveals widespread differences over the FRB, especially in
mountainous regions. The ANUSPLIN precipitation shows a considerable dry bias
in the Rocky Mountains, whereas the NARR winter air temperature is
2âŻÂ°C warmer than the other datasets over most of the FRB. In the VIC
simulations, the elevation-dependent changes in the maximum SWEÂ (maxSWE) are
more prominent at higher elevations of the Rocky Mountains, where the
PCIC-VIC simulation accumulates too much SWE and ANUSPLIN-VIC yields an
underestimation. Additionally, at each elevation range, the day of maxSWE
varies from 10Â to 20Â days between the VIC simulations. The snow melting
season begins early in the NARR-VIC simulation, whereas the PCIC-VIC
simulation delays the melting, indicating seasonal uncertainty in SWE
simulations. When compared with the observed runoff for the Fraser River main
stem at Hope, BC, the ANUSPLIN-VIC simulation shows considerable
underestimation of runoff throughout the water year owing to reduced
precipitation in the ANUSPLIN forcing dataset. The NARR-VIC simulation yields
more winter and spring runoff and earlier decline of flows in summer due to a
nearly 15-day earlier onset of the FRB springtime snowmelt.
Analysis of the parametric uncertainty in the VIC calibration process shows
that the choice of the initial parameter range plays a crucial role in
defining the model hydrological response for the FRB. Furthermore, the VIC
calibration process is biased toward cool and warm phases of the PDO and the
choice of proper calibration and validation time periods is important for
the experimental setup. Overall the VIC hydrological response is prominently
influenced by the uncertainties involved in the forcing datasets rather than
those in its parameter optimization and experimental setups
- âŠ