2,096 research outputs found
Variability in infants' functional brain network connectivity is associated with differences in affect and behavior
Variability in functional brain network connectivity has been linked to individual differences in cognitive, affective, and behavioral traits in adults. However, little is known about the developmental origins of such brain-behavior correlations. The current study examined functional brain network connectivity and its link to behavioral temperament in typically developing newborn and 1-month-old infants (M [age] = 25 days; N = 75) using functional near-infrared spectroscopy (fNIRS). Specifically, we measured long-range connectivity between cortical regions approximating fronto-parietal, default mode, and homologous-interhemispheric networks. Our results show that connectivity in these functional brain networks varies across infants and maps onto individual differences in behavioral temperament. Specifically, connectivity in the fronto-parietal network was positively associated with regulation and orienting behaviors, whereas connectivity in the default mode network showed the opposite effect on these behaviors. Our analysis also revealed a significant positive association between the homologous-interhemispheric network and infants' negative affect. The current results suggest that variability in long-range intra-hemispheric and cross-hemispheric functional connectivity between frontal, parietal, and temporal cortex is associated with individual differences in affect and behavior. These findings shed new light on the brain origins of individual differences in early-emerging behavioral traits and thus represent a viable novel approach for investigating developmental trajectories in typical and atypical neurodevelopment
Reference Sediment Selection in the Lower Mississippi Delta
Floodplain deposition has been a critical part in the evolution of Arkansas\u27 Delta ecoregion, and because ofits high potential for such events, this region is highly enriched and extremely fertile. Historically, water quality in the area has been the subject ofscientific study, and as a result littlehas been published on the effects of underlying sediment with associated benthic communities. Sediment analysis is critical to many of the ongoing aquatic studies because ofits significance as both a habitat for benthic organisms and a sink for contaminants. Seven rivers and one creek within the Delta ecoregion were examined for water chemistry, sediment characterization, and sediment toxicity to determine survival and growth of Chironomus tentans. Greatest midge growth occurred insediment collected from Black River site A; additionally, those sediments were high in silt content (\u3e80%) and supported high midge survival. The results of combined characterization and biological test methods indicated that the Black River (site A) was the sediment that met criteria set by the researchers and was suitable to use as a reference control sediment forfuture Delta toxicity testing
The determination of shock ramp width using the noncoplanar magnetic field component
We determine a simple expression for the ramp width of a collisionless fast
shock, based upon the relationship between the noncoplanar and main magnetic
field components. By comparing this predicted width with that measured during
an observation of a shock, the shock velocity can be determined from a single
spacecraft. For a range of low-Mach, low-beta bow shock observations made by
the ISEE-1 and -2 spacecraft, ramp widths determined from two-spacecraft
comparison and from this noncoplanar component relationship agree within 30%.
When two-spacecraft measurements are not available or are inefficient, this
technique provides a reasonable estimation of scale size for low-Mach shocks.Comment: 6 pages, LaTeX (aguplus + agutex);
packages:amsmath,times,graphicx,float, psfrag,verbatim; 3 postscript figures
called by the file; submitted to Geophys. Res. Let
Deconstructing the power resistance relationship for squats: a joint-level analysis
Generating high leg power outputs is important for executing rapid movements. Squats are commonly used to increase leg strength and power. Therefore, it is useful to understand factors affecting power output in squatting. We aimed to deconstruct the mechanisms behind why power is maximized at certain resistances in squatting. Ten male rowers (age = 20 ± 2.2 years; height = 1.82 ± 0.03 m; mass = 86 ± 11 kg) performed maximal power squats with resistances ranging from body weight to 80% of their one repetition maximum (1RM). Three-dimensional kinematics was combined with ground reaction force (GRF) data in an inverse dynamics analysis to calculate leg joint moments and powers. System center of mass (COM) velocity and power were computed from GRF data. COM power was maximized across a range of resistances from 40% to 60% 1RM. This range was identified because a trade-off in hip and knee joint powers existed across this range, with maximal knee joint power occurring at 40% 1RM and maximal hip joint power at 60% 1RM. A non-linear system force-velocity relationship was observed that dictated large reductions in COM power below 20% 1RM and above 60% 1RM. These reductions were due to constraints on the control of the movement
In-Stream Monitoring of Sediments and Water in the Lower Ouachita River for Site Impact to Aquatic Biota
Reported reduced sportfish densities in the main channel of the Ouachita River prompted an investigation, beginning in 1990, into potential causes of ongoing impairment to aquatic biota. In-stream monitoring that incorporated toxicity testing of sediments and water was conducted to discern potential sources of contaminants that might be related to the suboptimal fishery populations. Organisms selected to evaluate chronic impairment included larval fish, clams, midges and water fleas. The fathead minnow {Pimephales promelas) and cladoceran (Ceriodaphnia dubid) were used to estimate patterns of toxicity associated with water from seven designated reaches and selected tributaries of the Ouachita River. Larval survival and growth tests were conducted using the fathead minnow, while survival and reproduction were assessed for the cladoceran. An enzyme assay using the Asian clam (Corbicula fluminea), and growth and survival tests with Chironomus tentans were used to evaluate ambient sediment toxicity within these same reaches and tributaries. Ambient toxicity was rarely observed in the mainstem of the River and, moreover, represented intermittent events. However, impaired growth in larval fish, poor reproduction in cladocera, and reduced enzyme activity in clams were evident for several tributaries. Results of 10-day whole sediment tests showed significant growth reductions in C. tentans exposed to sediments collected from West and East Two bayous, Smackover and Coffee creeks. These results suggest there is intermittent impairment in tributaries of the Ouachita River due to ambient water and sediment conditions that are aside from current concerns for mercury contamination
Inferior vena cava branch variations in C57BL/6 mice have an impact on thrombus size in an IVC ligation (stasis) model
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110835/1/jth12866.pd
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