The roles of phonological short-term memory and working memory in L2 grammar and vocabulary learning

This study analyzed phonological short-term memory (PSTM) and working memory (WM) and their relationship with vocabulary and grammar learning in an artificial foreign language. Nonword repetition, nonword recognition, and listening span were used as memory measures. Participants learned the singular forms of vocabulary for an artificial foreign language before being exposed to plural forms in sentence contexts. Participants were tested on their ability to induce the grammatical forms and to generalize the forms to novel utterances. Individual differences in final abilities in vocabulary and grammar correlated between 0.44 and 0.76, depending on the measure. Despite these strong associations, the results demonstrated significant independent effects of PSTM and WM on L2 vocabulary learning and on L2 grammar learning, some of which were mediated by vocabulary and some of which were direct effects

Structural transformations and disordering in zirconolite (CaZrTi2O7) at high pressure

There is interest in identifying novel materials for use in radioactive waste applications and studying their behavior under high pressure conditions. The mineral zirconolite (CaZrTi2O7) exists naturally in trace amounts in diamond-bearing deep-seated metamorphic/igneous environments, and it is also identified as a potential ceramic phase for radionuclide sequestration. However, it has been shown to undergo radiation-induced metamictization resulting in amorphous forms. In this study we probed the high pressure structural properties of this pyrochlore-like structure to study its phase transformations and possible amorphization behavior. Combined synchrotron X-ray diffraction and Raman spectroscopy studies reveal a series of high pressure phase transformations. Starting from the ambient pressure monoclinic structure, an intermediate phase with P21/m symmetry is produced above 15.6 GPa via a first order transformation resulting in a wide coexistence range. Upon compression to above 56 GPa a disordered metastable phase III with a cotunnite-related structure appears that is recoverable to ambient conditions. We examine the similarity between the zirconolite behavior and the structural evolution of analogous pyrochlore systems under pressure.<br/

Time and location differentiated NOX control in competitive electricity markets using cap-and-trade mechanisms

Due to variations in weather and atmospheric chemistry, the timing and location of nitrogen oxide (NOX) reductions determine their effectiveness in reducing ground-level ozone, which adversely impacts human health. Electric generating plants are the primary stationary sources of NOX in most regions of the United States. In the Eastern U.S. they are subject to a summertime NOX cap and trade program that is not well matched to the time and locational impacts of NOX on ozone formation. We hypothesize that the integration of weather and atmospheric chemistry forecasting, a cap and trade system in which the "exchange rates" for permits can be varied by time and location based on these forecasts, and its application to a competitive wholesale electricity market, can achieve ozone standards more efficiently. To demonstrate the potential for reductions in NOX emissions in the short run, we simulate the magnitude of NOX reductions that can be achieved at various locations and times as a consequence of redispatch of generating units in the "classic" PJM region taking supply-demand balance constraints and network congestion into account. We report simulations using both a zonal model and an optimal power flow model.(cont.) We also estimate the relationship between the level NOX emission prices, competitive market responses to different levels of NOX prices, and the associated reductions in NOx emissions. The estimated maximum potential reductions, which occur at NOX prices of about $125,000/ton, are about 8 tons (20%) hourly in peak electricity demand hours and about 10 tons (50%) in average demand hours. We find that network constraints have little effect on the magnitude of the reductions in NOX emissions.Funding provided jointly by the U.S. Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA); as well as the CEEP

Implementing a time- and location-differentiated cap-and-trade program : flexible nitrogen oxide abatement from power plants in the eastern United States

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology, Management, and Policy Program, 2007.MIT Dewey Library copy: issued in leaves.Also issued printed in leaves.Includes bibliographical references (p. 197-206).Studies suggest that timing and location of emissions can change the amount of ozone formed from a given amount of nitrogen oxide (NOx) by a factor of five (Mauzerall et al. 2005). Yet existing NOx cap-and-trade programs require stationary sources in the Eastern U.S. to reduce emissions without reference to timing or location. This work is part of a larger study on whether a NOx cap-and-trade program that differentiates across emissions by time and location could reduce ozone concentrations more cost-effectively than simple aggregate reductions in the NOx cap in the Eastern United States. To gauge possible gains relative to existing regulations, this work examines compliance data from coal power plants in 2002 and 2005 to estimate the effectiveness of existing un-differentiated regulations. It finds that some plant operators chose to remain under aggregated caps by emitting less NOx during early summer months when effects on ozone formation are low and emitting more NOx during late summer months when effects on ozone formation are great. This behavior was at once individually rational, environmentally damaging, and perfectly legal. To evaluate potential challenges to implementation, the study assesses the technical feasibility and the distributional effects of spatially and temporally differentiated regulatory systems. * Are power plants in the Eastern U.S. technically capable of reducing NOx emissions in response to incentives that changed in time and by location given network constraints? To address these questions, this work used a zonal model based on an abstract network graph and optimal power flow simulations to estimate potential short-term NOx reductions and associated costs from redispatch of power plants in the original Pennsylvania-New Jersey-Maryland (PJM) power system.(cont.) Both methods estimated that power plants could respond with hourly NOx reductions of between 15 and 30% and that network constraints had little effect. * Are the distributional effects of a differentiated regulation likely to motivate and/or enable legal challenges that could undercut such a program? The distributional effects of differentiated regulation would depend on the timing and locations of reductions, and legal challenges could constrain implementation. But the inability of un-differentiated regulations to fully solve ozone problems, combined with scientific and economic justifications, and the ability of power plants to respond, justify further inquiry into the feasibility of differentiation.by Katherine C. Martin.Ph.D

Overlap of heritable influences between Cannabis Use Disorder, frequency of use and opportunity to use cannabis: Trivariate twin modelling and implications for genetic design

Background: The genetic component of Cannabis Use Disorder may overlap with influences acting more generally on early stages of cannabis use. This paper aims to determine the extent to which genetic influences on the development of cannabis abuse/dependence are correlated with those acting on the opportunity to use cannabis and frequency of use. Methods: A cross-sectional study of 3303 Australian twins, measuring age of onset of cannabis use opportunity, lifetime frequency of cannabis use, and lifetime DSM-IV cannabis abuse/dependence. A trivariate Cholesky decomposition estimated additive genetic (A), shared environment (C) and unique environment (E) contributions to the opportunity to use cannabis, the frequency of cannabis use, cannabis abuse/dependence, and the extent of overlap between genetic and environmental factors associated with each phenotype. Results: Variance components estimates were A = 0.64 [95% confidence interval (CI) 0.58–0.70] and E = 0.36 (95% CI 0.29–0.42) for age of opportunity to use cannabis, A = 0.74 (95% CI 0.66–0.80) and E = 0.26 (95% CI 0.20–0.34) for cannabis use frequency, and A = 0.78 (95% CI 0.65–0.88) and E = 0.22 (95% CI 0.12–0.35) for cannabis abuse/dependence. Opportunity shares 45% of genetic influences with the frequency of use, and only 17% of additive genetic influences are unique to abuse/dependence from those acting on opportunity and frequency. Conclusions: There are significant genetic contributions to lifetime cannabis abuse/dependence, but a large proportion of this overlaps with influences acting on opportunity and frequency of use. Individuals without drug use opportunity are uninformative, and studies of drug use disorders must incorporate individual exposure to accurately identify aetiology

Unbiased cut selection for optimal upper limits in neutrino detectors: the model rejection potential technique

We present a method for optimising experimental cuts in order to place the strongest constraints (upper limits) on theoretical signal models. The method relies only on signal and background expectations derived from Monte-Carlo simulations, so no bias is introduced by looking at actual data, for instance by setting a limit based on expected signal above the ``last remaining data event.'' After discussing the concept of the ``average upper limit,'' based on the expectation from an ensemble of repeated experiments with no true signal, we show how the best model rejection potential is achieved by optimising the cuts to minimise the ratio of this ``average upper limit'' to the expected signal from the model. As an example, we use this technique to determine the limit sensitivity of kilometre scale neutrino detectors to extra-terrestrial neutrino fluxes from a variety of models, e.g. active galaxies and gamma-ray bursts. We suggest that these model rejection potential optimised limits be used as a standard method of comparing the sensitivity of proposed neutrino detectors.Comment: 18 pages, 7 figures, submitted to Astroparticle Physic

Perilipin regulates the thermogenic actions of norepinephrine in brown adipose tissue

In response to cold, norepinephrine (NE)-induced triacylglycerol hydrolysis (lipolysis) in adipocytes of brown adipose tissue (BAT) provides fatty acid substrates to mitochondria for heat generation (adaptive thermogenesis). NE-induced lipolysis is mediated by protein kinase A (PKA)-dependent phosphorylation of perilipin, a lipid droplet-associated protein that is the major regulator of lipolysis. We investigated the role of perilipin PKA phosphorylation in BAT NE-stimulated thermogenesis using a novel mouse model in which a mutant form of perilipin, lacking all six PKA phosphorylation sites, is expressed in adipocytes of perilipin knockout (Peri KO) mice. Here, we show that despite a normal mitochondrial respiratory capacity, NE-induced lipolysis is abrogated in the interscapular brown adipose tissue (IBAT) of these mice. This lipolytic constraint is accompanied by a dramatic blunting (∼70%) of the in vivo thermal response to NE. Thus, in the presence of perilipin, PKA-mediated perilipin phosphorylation is essential for NE-dependent lipolysis and full adaptive thermogenesis in BAT. In IBAT of Peri KO mice, increased basal lipolysis attributable to the absence of perilipin is sufficient to support a rapid NE-stimulated temperature increase (∼3.0°C) comparable to that in wild-type mice. This observation suggests that one or more NE-dependent mechanism downstream of perilipin phosphorylation is required to initiate and/or sustain the IBAT thermal response

Social behaviour and collective motion in plant-animal worms

© 2016 The Author(s) Published by the Royal Society. All rights reserved. Social behaviour may enable organisms to occupy ecological niches that would otherwise be unavailable to them. Here, we test this major evolutionary prin- ciple by demonstrating self-organizing social behaviour in the plant-animal, Symsagittifera roscoffensis. These marine aceol flat worms rely for all of their nutrition on the algae within their bodies: hence their common name. We show that individual worms interact with one another to coordinate their movements so that even at low densities they begin to swim in small polarized groups and at increasing densities such flotillas turn into circular mills. We use computer simulations to: (i) determine if real worms interact socially by com- paring them with virtual worms that do not interact and (ii) show that the social phase transitions of the real worms can occur based only on local inter- actions between and among them. We hypothesize that such social behaviour helps the worms to form the dense biofilms or mats observed on certain sun- exposed sandy beaches in the upper intertidal of the East Atlantic and to become in effect a super-organismic seaweed in a habitat where macro-algal seaweeds cannot anchor themselves. Symsagittifera roscoffensis, a model organ- ism in many other areas in biology (including stem cell regeneration), also seems to be an ideal model for understanding how individual behaviours can lead, through collective movement, to social assemblages

Long-term outcomes of catheterizable continent urinary channels: what do you use, where you put it and does it matter?

Introduction Appendicovesicostomy (APV) and Monti ileovesicostomy (Monti) are commonly used catheterizable channels with similar outcomes on short-term follow-up. Their relative long-term results have not been previously published. Objective Our goal was to assess long-term durability of APV and Monti channels in a large patient cohort. Study design In this retrospective cohort study, we retrospectively reviewed consecutive patients ≤21 years old undergoing APV and Monti surgery at our institution (1990–2013). We collected data on demographics, channel type, location, continence and stomal and subfascial revisions. Kaplan–Meier survival and Cox proportional hazards analysis were used. Results Of 510 patients meeting inclusion criteria, 214 patients had an APV and 296 had a Monti (50.5% spiral Monti). Median age at surgery was 7.4 years for APV (median follow-up: 5.7 years) and 8.7 years for Monti (follow-up: 7.7 years). Stomal stenosis, overall stomal revisions and channel continence were similar for APV and Monti (p ≥ 0.26). Fourteen APVs (6.5%) had subfascial revisions compared to 49 Montis (16.6%, p = 0.001). On survival analysis, subfascial revision risk at 10 years for APV was 8.6%, Monti channels excluding spiral umbilical Monti: 15.5% and spiral umbilical Monti: 32.3% (p < 0.0001, Figure). On multivariate regression, Monti was 2.09 times more likely than APV to undergo revision (p = 0.03). The spiral Monti to the umbilicus, in particular, was 4.23 times more likely than APV to undergo revision (p < 0.001). Concomitant surgery, gender, age and surgery date were not significant predictors of subfascial revision (p ≥ 0.17). Stomal location was significant only for spiral Montis. Discussion Our study has several limitations. Although controlling for surgery date was a limited way of adjusting for changing surgical techniques, residual confounding by surgical technique is unlikely, as channel implantation technique was typically unrelated to channel type. We did not include complications managed conservatively or endoscopically. In addition, while we did not capture patients who were lost to follow-up, we attempted to control for this through survival analysis. Conclusions We demonstrate, durable long-term results with the APV and Monti techniques. The risk of channel complications continues over the channel's lifetime, with no difference in stomal complications between channels. At 10 years after initial surgery, Monti channels were twice as likely to undergo a subfascial revision (1 in 6) than APV (1 in 12). The risk is even higher in for the spiral umbilical Monti (1 in 3)

Arterial Switch for Transposition of the Great Arteries

Background Reports of long-term mortality and reintervention after transposition of the great arteries with intact ventricular septum treatment, although favorable, are mostly limited to single-center studies. Even less is known about hospital resource utilization (days at hospital) and the impact of treatment choices and timing on outcomes. Objectives The purpose of this study was to describe survival, reintervention and hospital resource utilization after arterial switch operation (ASO) in a national dataset. Methods Follow-up and life status data for all patients undergoing ASO between 2000 and 2017 in England and Wales were collected and explored using multivariable regressions and matching. Results A total of 1,772 patients were identified, with median ASO age of 9.5 days (IQR: 6.5-14.5 days). Mortality and cardiac reintervention at 10 years after ASO were 3.2% (95% CI: 2.5%-4.2%) and 10.7% (95% CI: 9.1%-12.2%), respectively. The median time spent in hospital during the ASO spell was 19 days (IQR: 14, 24). Over the first year after the ASO patients spent 7 days (IQR: 4-10 days) in hospital in total, decreasing to 1 outpatient day/year beyond the fifth year. In a subgroup with complete risk factor data (n = 652), ASO age, and balloon atrial septostomy (BAS) use were not associated with late mortality and reintervention, but cardiac or congenital comorbidities, low weight, and circulatory/renal support at ASO were. After matching for patient characteristics, BAS followed by ASO and ASO as first procedure, performed within the first 3 weeks of life, had comparable early and late outcomes, including hospital resource utilization. Conclusions Mortality and hospital resource utilization are low, while reintervention remains relatively frequent. Early ASO and individualized use of BAS allows for flexibility in treatment choices and a focus on at-risk patients