Topic and background knowledge effects on performance in speaking assessment

This study explores the extent to which topic and background knowledge of topic affect spoken performance in a high-stakes speaking test. It is argued that evidence of a substantial influence may introduce construct-irrelevant variance and undermine test fairness. Data were collected from 81 non-native speakers of English who performed on 10 topics across three task types. Background knowledge and general language proficiency were measured using self-report questionnaires and C-tests respectively. Score data were analysed using many-facet Rasch measurement and multiple regression. Findings showed that for two of the three task types, the topics used in the study generally exhibited difficulty measures which were statistically distinct. However, the size of the differences in topic difficulties was too small to have a large practical effect on scores. Participants’ different levels of background knowledge were shown to have a systematic effect on performance. However, these statistically significant differences also failed to translate into practical significance. Findings hold implications for speaking performance assessment

Distributed Binary Detection over Fading Channels: Cooperative and Parallel Architectures

This paper considers the problem of binary distributed detection of a known signal in correlated Gaussian sensing noise in a wireless sensor network, where the sensors are restricted to use likelihood ratio test (LRT), and communicate with the fusion center (FC) over bandwidth-constrained channels that are subject to fading and noise. To mitigate the deteriorating effect of fading encountered in the conventional parallel fusion architecture, in which the sensors directly communicate with the FC, we propose new fusion architectures that enhance the detection performance, via harvesting cooperative gain (so-called decision diversity gain). In particular, we propose: (i) cooperative fusion architecture with Alamouti's space-time coding (STC) scheme at sensors, (ii) cooperative fusion architecture with signal fusion at sensors, and (iii) parallel fusion architecture with local threshold changing at sensors. For these schemes, we derive the LRT and majority fusion rules at the FC, and provide upper bounds on the average error probabilities for homogeneous sensors, subject to uncorrelated Gaussian sensing noise, in terms of signal-to-noise ratio (SNR) of communication and sensing channels. Our simulation results indicate that, when the FC employs the LRT rule, unless for low communication SNR and moderate/high sensing SNR, performance improvement is feasible with the new fusion architectures. When the FC utilizes the majority rule, such improvement is possible, unless for high sensing SNR

On Power Allocation for Distributed Detection with Correlated Observations and Linear Fusion

We consider a binary hypothesis testing problem in an inhomogeneous wireless sensor network, where a fusion center (FC) makes a global decision on the underlying hypothesis. We assume sensors observations are correlated Gaussian and sensors are unaware of this correlation when making decisions. Sensors send their modulated decisions over fading channels, subject to individual and/or total transmit power constraints. For parallel-access channel (PAC) and multiple-access channel (MAC) models, we derive modified deflection coefficient (MDC) of the test statistic at the FC with coherent reception.We propose a transmit power allocation scheme, which maximizes MDC of the test statistic, under three different sets of transmit power constraints: total power constraint, individual and total power constraints, individual power constraints only. When analytical solutions to our constrained optimization problems are elusive, we discuss how these problems can be converted to convex ones. We study how correlation among sensors observations, reliability of local decisions, communication channel model and channel qualities and transmit power constraints affect the reliability of the global decision and power allocation of inhomogeneous sensors

Stop and Frisk: The Human Impact

The New York City Police Department's (NYPD's) aggressive stop-and-frisk practices are having a profound effect on individuals, groups and communities across the city. This report documents some of the human stories behind the staggering statistics and sheds new light on the breadth of impact this policy is having on individuals and groups, in neighborhoods, and citywide.The NYPD stop-and-frisk program affects thousands of people every day in New York City and it is widely acknowledged that an overwhelming majority of those people are Black or Latino. This report shows that many are also members of a range of other communities that are experiencing devastating impact from this program, including LGBTQ/GNC people, non-citizens, homeless people, religious minorities, low-income people, residents of certain neighborhoods and youth. Residents of some New York City neighborhoods describe a police presence so pervasive and hostile that they feel like they are living in a state of siege

Effect of garlic on liver phosphatidate phosphohydrolase and plasma lipid levels in hyperlipidemic rats

Studies on the effects of garlic (Allium sativum) on hyperlipidemia have demonstrated somewhat controversial results and there have been few studies on its enzymatic mechanism. The purpose of this study was to assess the effect of garlic on the liver phosphatidate phosphohydrolase (PAP) activity, plasma lipid levels, malondialdehyde (MDA) and plasma antioxidant in rats fed either by normal or high-lipogenic diet with or without garlic. Male Wistar rats were fed by standard pellet diet (group I), standard diet supplemented with 4% garlic (group II), lipogenic diet (containing sunflower oil, cholesterol and ethanol) plus 4% garlic (group III) and only lipogenic diet (group IV). Results showed that garlic significantly reduced total cholesterol (TC), plasma triglyceride (TG), LDL-C, VLDL-C, liver triglyceride, plasma malondialdehyde (MDA) and elevated plasma antioxidant in garlic treated rats (groups II and III) compared to group IV (lipogenic diet group). Also, liver PAP activity was decreased in group II than group I whereas, the decrease in its activity in groups III and IV was due to the accumulation of triglyceride in liver. Therefore, the results are clearly indicative of the beneficial effects of garlic in reducing lateral side effects of hyperlipidemia. (C) 2011 Elsevier Ltd. All rights reserved

Beneficial effects of artichoke on liver phosphatidate phosphohydrolase and plasma lipids in rats fed by lipogenic diet

Artichoke (Cynara scolymus L.) is full of natural antioxidants and has a lipid-lowering effect. The aim of this study was to investigate the effect of artichoke on the liver phosphatidate phosphohydrolase, plasma lipid levels, plasma malondialdehyde, and plasma antioxidant in rats fed by lipogenic diet. Male rats were fed by standard pellet diet (group I), standard diet supplemented with 10 artichoke (group II), lipogenic diet (containing sunflower oil, cholesterol and ethanol) plus 10 artichoke (group III) and only lipogenic diet (group IV). On day 60 of the experiment, liver phosphatidate phosphohydrolase activity, liver triglyceride, plasma lipids, plasma malondialdehyde, and plasma antioxidant levels were measured. Phosphatidate phosphohydrolase activity, liver triglyceride, the ratio of total cholesterol to high density lipoprotein cholesterol, plasma total cholesterol and triglyceride levels were significantly decreased due to artichoke treatment in groups II and III compared to groups I and IV, respectively. Significant reduction in plasma malondialdehyde and significant elevation in plasma antioxidant power observed in groups II and III compared to groups I and IV, respectively. The results clearly indicated that artichoke can be useful for the reduction of phosphatidate phosphohydrolase activity and liver triglyceride. Also, artichoke has beneficial effects in the controlling of hyperlipidemia, abnormalities in lipid profiles and oxidative stress in hyperlipidemic regimes

Yoga for mental health of children: a short review

This review paper aims to introduce yoga as a method for dealing with stress of children, and discusses how it can help them to balance body and emotion. Children need to listen inward: to their bodies, ideas and their feelings. Yoga helps children on being self aware and taking part in social activities. Method: This review attempted to gather the relevant papers that were previously published on the subject. PubMed, Scopus, and Google Scholar were the sources for findings the articles. Only the articles that were published not later than 2005 were selected. Results: Nowadays, children’s expectations are higher than in the past, and their interest on the internet, media, and other communication technologies has increased. Using these media devices and the time that they spend on it may influence their lifestyles negatively and cause stress. While these technologies are very useful in their life for communication even in learning and entertainment, these sources can also lead to undeveloped attention. This article is suggesting yoga as a helpful method for children to deal with their stress, and to increase their well-being, mental health, and positive feelings. Conclusion: Yoga aids to improve physical and mental health among children and helps students in enhancing resilience, mood and self-regulation skills related to emotion and stress

Photonic band gap in isotropic hyperuniform disordered solids with low dielectric contrast

We report the first experimental demonstration of a TE-polarization photonic band gap (PBG) in a 2D isotropic hyperuniform disordered solid (HUDS) made of dielectric media with a index contrast of 1.6:1, very low for PBG formation. The solid is composed of a connected network of dielectric walls enclosing air-filled cells. Direct comparison with photonic crystals and quasicrystals permitted us to investigate band-gap properties as a function of increasing rotational isotropy. We present results from numerical simulations proving that the PBG observed experimentally for HUDS at low index contrast has zero density of states. The PBG is associated with the energy difference between complementary resonant modes above and below the gap, with the field predominantly concentrated in the air or in the dielectric. The intrinsic isotropy of HUDS may offer unprecedented flexibilities and freedom in applications (i. e. defect architecture design) not limited by crystalline symmetries