3,909 research outputs found
Social and Emotional Development and Language Outcomes in Mixed Income Preschool Classroom Environments
Two different publicly funded preschool programs exist within Arkansas: Head Start and the Arkansas Better Chance (ABC) program. Though philosophically similar, the different programs have dramatically different income eligibility guidelines resulting in classrooms with differing levels of economic diversity. Independent samples t-tests were conducted on initial, final, and growth scores in Personal and Social Development and in the area of Language and Literacy Development. The program with higher income guidelines had higher initial and final scores, but mixed growth scores. Multiple regression analyses indicated that starting score was the single greatest predictor of growth and of final scores. Growth was inversely but significantly linked to start score, while final score was significantly linked to start score. No single factor had greater predictive power than starting score. Neither the ABC classroom nor the Head Start classroom demonstrated a significant benefit in growth or final score outcomes at p=0.05
Social Capital and Academic Achievement in Arkansas
The purpose of this study is to demonstrate a more comprehensive understanding of the impact that a child’s broader context has upon his or her academic outcomes, and presumably, life. Using Bronfenbrenner’s theory of human development, this study examines the extent to which social capital and student achievement are correlated and whether an infusion of funding for schools that presumably lack social and economic capital might predict academic achievement in schools from economically depressed regions. Findings indicate that some aspects of social capital and funding initiatives have a demonstrated impact on student achievement but there is not a correlation with student achievement and per pupil funding. Additionally, indexed measures of social capital were found to have limitations, though some determinants of social capital index were more effective in predicting student achievement than others. This study suggests that there may be malleable community factors that could be leveraged to improve academic achievement that warrant additional research
Social Capital and Academic Achievement in Arkansas
The purpose of this study is to demonstrate a more comprehensive understanding of the impact that a child’s broader context has upon his or her academic outcomes, and presumably, life. Using Bronfenbrenner’s theory of human development, this study examines the extent to which social capital and student achievement are correlated and whether an infusion of funding for schools that presumably lack social and economic capital might predict academic achievement in schools from economically depressed regions. Findings indicate that some aspects of social capital and funding initiatives have a demonstrated impact on student achievement but there is not a correlation with student achievement and per pupil funding. Additionally, indexed measures of social capital were found to have limitations, though some determinants of social capital index were more effective in predicting student achievement than others. This study suggests that there may be malleable community factors that could be leveraged to improve academic achievement that warrant additional research
Characterisation of two alcohol acyltransferases from kiwifruit (Actinidia spp.) reveals distinct substrate preferences.
Volatile esters are key compounds of kiwifruit flavour and are formed by alcohol acyltransferases that belong to the BAHD acyltransferase superfamily. Quantitative RT-PCR was used to screen kiwifruitderived expressed sequence tags with proposed acyltransferase function in order to select ripeningspecific sequences and test their involvement in alcohol acylation. The screening criterion was for at least 10-fold increased transcript accumulation in ripe compared with unripe kiwifruit and in response to ethylene. Recombinant expression in yeast revealed alcohol acyltransferase activity for Actinidia-derived AT1, AT16 and the phylogenetically distinct AT9, using various alcohol and acyl-CoA substrates. Functional characterisation of AT16 and AT9 demonstrated striking differences in their substrate preferences and apparent catalytic efficiencies ðV0 max K�1 m Þ. Thus revealing benzoyl-CoA:alcohol O-acyltransferase activity for AT16 and acetyl-CoA:alcohol O-acyltransferase activity for AT9. Both kiwifruit-derived enzymes displayed higher reaction rates with butanol compared with ethanol, even though ethanol is the main alcohol in ripe fruit. Since ethyl acetate and ethyl benzoate are major esters in ripe kiwifruit, we suggest that fruit characteristic volatile profiles result from a combination of substrate availability and specificity of individual alcohol acyltransferases
The Hamiltonian structure and Euler-Poincar\'{e} formulation of the Vlasov-Maxwell and gyrokinetic systems
We present a new variational principle for the gyrokinetic system, similar to
the Maxwell-Vlasov action presented in Ref. 1. The variational principle is in
the Eulerian frame and based on constrained variations of the phase space fluid
velocity and particle distribution function. Using a Legendre transform, we
explicitly derive the field theoretic Hamiltonian structure of the system. This
is carried out with a modified Dirac theory of constraints, which is used to
construct meaningful brackets from those obtained directly from
Euler-Poincar\'{e} theory. Possible applications of these formulations include
continuum geometric integration techniques, large-eddy simulation models and
Casimir type stability methods.
[1] H. Cendra et. al., Journal of Mathematical Physics 39, 3138 (1998)Comment: 36 pages, 1 figur
Insect olfaction and the evolution of receptor tuning
Insects detect odorants primarily using odorant receptors (OR) housed in the dendritic membrane of olfactory sensory neurons (OSN). Pioneering studies indicated that insects, like mammals, detect odorants in a combinatorial fashion with a specific odor ligand activating several broadly tuned ORs, and each OR being activated by several ligands. Several recent studies, however, challenge this view by providing examples where ecologically relevant odorants are detected by high-specificity ORs activating dedicated neuronal circuits. Here we review these contrasting findings on the ligand selectivity of insect ORs and their neuronal wiring, and outline scenarios describing how adaptive and neutral evolution might shape both narrow and broad receptor tuning. The fact that not all ORs display narrow tuning might partly be due to key ligands having been missed from screens or too high stimuli concentrations being used. However, the birth-and-death model of OR evolution, involving both adaptive and neutral events, could also explain the evolution of broad tuning in certain receptors due to positive selection or relaxed constraint. If the insect olfactory system indeed contains both narrowly and broadly tuned ORs, this suggests that it is a hybrid between dedicated channels and combinatorial coding. The relative extent of the two coding modes is then likely to differ between species, depending on requirements of perceived chemical space and the size of the OR repertoire. We address this by outlining scenarios where certain insect groups may be more likely to have evolved combinatorial coding as their dominant coding strategy. Combinatorial coding may have evolved predominantly in insects that benefit from the ability to discriminate between a larger number of odorants and odor objects, such as polyphagous or social species. Alternatively, combinatorial coding may have evolved simply as a mechanism to increase perceived odor space in species with small OR repertoires
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Trauma ICU Prevalence Project: the diversity of surgical critical care.
Background:Surgical critical care is crucial to the care of trauma and surgical patients. This study was designed to provide a contemporary assessment of patient types, injuries, and conditions in intensive care units (ICU) caring for trauma patients. Methods:This was a multicenter prevalence study of the American Association for the Surgery of Trauma; data were collected on all patients present in participating centers' trauma ICU (TICU) on November 2, 2017 and April 10, 2018. Results:Forty-nine centers submitted data on 1416 patients. Median age was 58 years (IQR 41-70). Patient types included trauma (n=665, 46.9%), non-trauma surgical (n=536, 37.8%), medical (n=204, 14.4% overall), or unspecified (n=11). Surgical intensivists managed 73.1% of patients. Of ICU-specific diagnoses, 57% were pulmonary related. Multiple high-intensity diagnoses were represented (septic shock, 10.2%; multiple organ failure, 5.58%; adult respiratory distress syndrome, 4.38%). Hemorrhagic shock was seen in 11.6% of trauma patients and 6.55% of all patients. The most common traumatic injuries were rib fractures (41.6%), brain (38.8%), hemothorax/pneumothorax (30.8%), and facial fractures (23.7%). Forty-four percent were on mechanical ventilation, and 17.6% had a tracheostomy. One-third (33%) had an infection, and over half (54.3%) were on antibiotics. Operations were performed in 70.2%, with 23.7% having abdominal surgery. At 30 days, 5.4% were still in the ICU. Median ICU length of stay was 9 days (IQR 4-20). 30-day mortality was 11.2%. Conclusions:Patient acuity in TICUs in the USA is very high, as is the breadth of pathology and the interventions provided. Non-trauma patients constitute a significant proportion of TICU care. Further assessment of the global predictors of outcome is needed to inform the education, research, clinical practice, and staffing of surgical critical care providers. Level of evidence:IV, prospective observational study
Cognitive Motivations and Sensation Seeking as Long-Term Predictors of Drinking Problems
The development of comprehensive theories regarding the determinants ofvulnerability toward drinking problems depends in part on longitudinal evidencelinking psychosocial precursors to clinically-relevant problem consequences. Inan investigation of some of the more promising psychosocial precursors ofproblem vulnerability, we evaluated the long-term predictive effects of adolescentcognitive motivations for alcohol use and sensation seeking on a wide variety ofadult drinking-problem consequences including driving while intoxicated (DWI).Results indicated that the Cognitive Motivation factor was a significant, independent, nine-year predictor of a factor of Drinking-Problem Consequences. Over this same period, certain cognitive motivation and sensation seeking indicators independently predicted DWI, and the Sensation Seeking factor independently predicted Cognitive Motivation and Alcohol Use factors. The significant, independent effects on problem-drinking variables demonstrated that psychosocial vulnerability appeared across a range of consumption levels. These findings have important implications for counseling practices and the identification of teenagers of high-risk for drinking problems and DWI in later adulthood
First Results from SPARO: Evidence for Large-Scale Toroidal Magnetic Fields in the Galactic Center
We have observed the linear polarization of 450 micron continuum emission
from the Galactic center, using a new polarimetric detector system that is
operated on a 2 m telescope at the South Pole. The resulting polarization map
extends ~ 170 pc along the Galactic plane and ~ 30 pc in Galactic latitude, and
thus covers a significant fraction of the central molecular zone. Our map shows
that this region is permeated by large-scale toroidal magnetic fields. We
consider our results together with radio observations that show evidence for
poloidal fields in the Galactic center, and with Faraday rotation observations.
We compare all of these observations with the predictions of a magnetodynamic
model for the Galactic center that was proposed in order to explain the
Galactic Center Radio Lobe as a magnetically driven gas outflow. We conclude
that the observations are basically consistent with the model.Comment: 11 pages, 2 figures, 1 table, submitted to ApJ Let
Interactive and Higher-Order Effects of Social Influences on Drug Use
The study of moderators and higher-order effects of social influences on drug use has many implications for theories of health behavior. In the present study, we investigated the longitudinal predictive effects of some of the prominent moderator variables that represent forms of susceptibility toward social influence in teenage drug use. We also studied the possibility that social influence may predict drug use in nonlinear (quadratic) forms, consistent with theories proposing that threshold or decelerating effects may occur in social influences on normatively sanctioned behaviors. Results showed that several of the interactive and quadratic predictive effects were significant. The findings supported the views that certain moderator variables act as buffers, which either protect the individual from social pressures to use drugs, or make the individual more susceptible to such pressures. In addition, two of the obtained quadratic effects of social influence lent support to the application of social impact theory to drug use. Overall, our findings suggest that interactive and nonlinear approaches to social influences on drug use provide a unique and viable theoretical perspective from which to construe this problem health behavior
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