10,247 research outputs found

    The Effects of Inference-Training and Text Repetition on Chinese Learners' Incidental Vocabulary Acquisition While Listening

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    This article reports a study of the effects of inference training and text repetition on Chinese university students’ performance of two listening information-transfer tasks that provided built-in measures of their comprehension and opportunities for the acquisition of ten unknown target words embedded in the listening texts. One group just listened to the text once, a second group three times, while the third listened three times and received inference-training support. The results showed that text repetition had a positive effect on both comprehension and vocabulary acquisition. However, the inference-training had no additional effect. The study lends support to the findings of previous studies which have shown that repeated opportunities to process oral input have a positive effect on listening comprehension and extends these studies by showing that it also facilitates incidental vocabulary acquisition

    The ecology, biogeography, history and future of two globally important weeds : Cardiospermum halicacabum Linn. and C. grandiflorum Sw.

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    Members of the balloon vine genus, Cardiospermum, have been extensively moved around the globe as medicinal and horticultural species, two of which are now widespread invasive species; C. grandiflorum and C. halicacabum. A third species, C. corindum, may also have significant invasion potential. However, in some regions the native status of these species is not clear, hampering management. For example, in South Africa it is unknown whether C. halicacabum and C. corindum are native, and this is a major constraint to on-going biological control programmes against invasive C. grandiflorum. We review the geography, biology and ecology of selected members of the genus with an emphasis on the two most widespread invaders, C. halicacabum and C. grandiflorum. Specifically, we use molecular data to reconstruct a phylogeny of the group in order to shed light on the native ranges of C. halicacabum and C. corindum in southern Africa. Phylogenetic analyses indicate that southern African accessions of these species are closely related to South American taxa indicating human-mediated introduction and/or natural long distance dispersal. Then, on a global scale we use species distribution modelling to predict potential suitable climate regions where these species are currently absent. Native range data were used to test the accuracy with which bioclimatic modelling can identify the known invasive ranges of these species. Results show that Cardiospermum species have potential to spread further in already invaded or introduced regions in Australia, Africa and Asia, underlining the importance of resolving taxonomic uncertainties for future management efforts. Bioclimatic modelling predicts Australia to have highly favourable environmental conditions for C. corindum and therefore vigilance against this species should be high. Species distribution modelling showed that native range data over fit predicted suitable ranges, and that factors other than climate influence establishment potential. This review opens the door to better understand the global biogeography of the genus Cardiospermum, with direct implications for management, while also highlighting gaps in current research

    The Dynamics of Drug Trafficking/ Smuggling by Female Offenders in the Trinidad and Tobago Prison Service: An Exploratory Mixed-Methods Approach

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    Female offenders incarcerated for the crime of drug trafficking/smuggling have received little research attention. This thesis is an exploratory study designed to help fill that gap. As such, the study is primarily focused on women involved in the illicit drug economy via their participation in drug trafficking/ smuggling activities and secondarily focused on the general population of females incarcerated/remanded for various other crimes. Within the relevant body of research the term trafficking is loosely utilized (Fleetwood 2009). Thus to provide clarity, in this research project the terms trafficking and smuggling are used interchangeably and specifically reference the act of international import and export of drugs (2009). This research, which was conducted at the women\u27s facility in Arouca, Trinidad at the Trinidad and Tobago Prison Service (TIPS), analyzed relevant experiences of females incarcerated/remanded by addressing three central questions: What are the main factors that influenced the female offender\u27s decision to engage in drug trafficking/ smuggling activities?, How was the female offender recruited to become a drug smuggler/trafficker?, At what point did the female offender become involved with drug trafficking/ smuggling activities? These core research questions were addressed by conducting in-depth semi-structured interviews with (13) thirteen participants and administering a survey instrument to the broader population of inmates in the Women\u27s Prison. This research, which explored the relevant aspects of the women\u27s lives as well as the incidents leading up to their initiation into drug smuggling, was achieved by probing both general and specific past experiences via questions pertaining to women\u27s educational and criminal history, abuse and other criminogenic factors. Ultimately, the in-depth interview analysis provides a framework for understanding the female drug smugglers of TIPS and offers some preliminary insight into this neglected area. Interview and survey data indicate that many women were tricked or became involved in drug trafficking via false pretense. Furthermore, all females in this study functioned on the lower levels of this illicit industry, having little information regarding higher level operations. This suggests that a more in-depth qualitative study should be conducted in order to collect more detailed information from larger samples of women from various prison facilities in the Caribbean, United Kingdom, Canada and elsewhere. Overall this research produced three major findings which covered women\u27s Motivation, Recruitment and Involvement. These findings suggest that women were not simply motivated by monetary gain, women traffickers made the autonomous decision, were lured, and were tricked into drug trafficking via their personal relationships with men

    Novel Electroweak Symmetry Breaking Conditions From Quantum Effects In The MSSM

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    We present, in the context of the Minimal Supersymmetric Standard Model, a detailed one-loop analytic study of the minimization conditions of the effective potential in the Higgs sector. Special emphasis is put on the role played by StrM4Str M^4 in the determination of the electroweak symmetry breaking conditions, where first and second order derivatives of the effective potential are systematically taken into account. Novel, necessary (and sufficient in the Higgs sector) model-independent constraints, are thus obtained analytically, leading to new theoretical lower and upper bounds on tanβ\tan \beta. Although fully model-independent, these bounds are found to be much more restrictive than the existing model-dependent ones! A first illustration is given in the context of a SUGRA-GUT motivated scenario.Comment: Latex, 45 pages, 5 figure

    Inhibition of food intake in obese subjects by peptide YY3-36

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    Background: The gut hormone fragment peptide YY3-36 (PYY) reduces appetite and food intake when infused into subjects of normal weight. In common with the adipocyte hormone leptin, PYY reduces food intake by modulating appetite circuits in the hypothalamus. However, in obesity there is a marked resistance to the action of leptin, which greatly limits its therapeutic effectiveness. We investigated whether obese subjects were also resistant to the anorectic effects of PYY.Methods: We compared the effects of PYY infusion on appetite and food intake in 12 obese and 12 lean subjects in a double-blind, placebo-controlled, crossover study. The plasma levels of PYY, ghrelin, leptin, and insulin were also determined.Results: Caloric intake during a buffet lunch offered two hours after the infusion of PYY was decreased by 30 percent in the obese subjects (P<0.001) and 31 percent in the lean subjects (P<0.001). PYY infusion also caused a significant decrease in the cumulative 24-hour caloric intake in both obese and lean subjects. PYY infusion reduced plasma levels of the appetite-stimulatory hormone ghrelin. Endogenous fasting and postprandial levels of PYY were significantly lower in obese subjects (the mean [+/-SE] fasting PYY levels were 10.2+/-0.7 pmol per liter in the obese group and 16.9+/-0.8 pmol per liter in the lean group, P<0.001). Furthermore, the fasting PYY levels correlated negatively with the body-mass index (r=-0.84, P<0.001).Conclusions: We found that obese subjects were not resistant to the anorectic effects of PYY. Endogenous PYY levels were low in the obese subjects, suggesting that PYY deficiency may contribute to the pathogenesis of obesity

    Invariant indices of polarimetric purity. Generalized indices of purity for nxn covariance matrices

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    A proper set of indices characterizing the polarimetric purity of light and material media is defined from the eigenvalues of the corresponding coherency matrix. A simple and generalizable relation of these indices with the current parameters characterizing the global purity is obtained. A general definition for systems characterized by nxn positive semidefinite Hermitian matrices is introduced in terms of the corresponding eigenvalues and diagonal Gell-Mann matrices. The set of n-1 indices of purity has a nested structure and provide complete information about the statistical purity of the system.Comment: 19 pages, 2 figure

    The Gaseous Extent of Galaxies and the Origin of \lya Absorption Systems. III. Hubble Space Telescope Imaging of \lya-Absorbing Galaxies at z < 1

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    We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies identified in an imaging and spectroscopic survey of faint galaxies in fields of HST spectroscopic target QSOs. We measure properties of 87 galaxies, of which 33 are associated with corresponding \lya absorption systems and 24 do not produce corresponding \lya absorption lines to within sensitive upper limits. Considering only galaxy and absorber pairs that are likely to be physically associated and excluding galaxy and absorber pairs within 3000 \kms of the background QSOs leaves 26 galaxy and absorber pairs and seven galaxies that do not produce corresponding \lya absorption lines to within sensitive upper limits. Redshifts of the galaxy and absorber pairs range from 0.0750 to 0.8912 with a median of 0.3718, and impact parameter separations of the galaxy and absorber pairs range from 12.4 to 157.4h1157.4 h^{-1} kpc with a median of 62.4h162.4 h^{-1} kpc. The primary result of the analysis is that the amount of gas encountered along the line of sight depends on the galaxy impact parameter and B-band luminosity but does not depend strongly on the galaxy average surface brightness, disk-to-bulge ratio, or redshift. This result confirms and improves upon the anti-correlation between \lya absorption equivalent width and galaxy impact parameter found previously by Lanzetta et al. (1995). There is no evidence that galaxy interactions play an important role in distributing tenuous gas around galaxies in most cases. Galaxies might account for all \lya absorption systems with W>0.3W > 0.3 \AA, but this depends on the unknown luminosity function and gaseous cross sections of low-luminosity galaxies as well as on the uncertainties of the observed number density of \lya absorption systems.Comment: Minor changes. Figure 1 stays intact and is available at ftp://ftp.ess.sunysb.edu/pub/lanzetta/wfpc

    Spectroscopic follow up of arclets in AC114 with the VLT

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    We present the first results on the VLT/FORS-1 spectroscopic survey of amplified sources and multiple images in the lensing cluster AC114. Background sources were selected in the cluster core, close to the critical lines, using photometric redshifts combined with lensing inversion criteria. Spectroscopic results are given, together with a brief summary of the properties of some of these high-z galaxies.Comment: 4pages. To appear in the Proceedings of the XXth Moriond Astrophysics Meeting "Cosmological Physics with Gravitational Lensing", eds. J.-P. Kneib, Y. Mellier, M. Moniez and J. Tran Thanh Van, Les Arcs, France, March 11th-18th 200

    \u3ci\u3eVarroa\u3c/i\u3e mites and honey bee health: can \u3ci\u3eVarroa\u3c/i\u3e explain part of the colony losses?

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    Since 2006, disastrous colony losses have been reported in Europe and North America. The causes of the losses were not readily apparent and have been attributed to overwintering mortalities and to a new phenomenon called Colony Collapse Disorder. Most scientists agree that there is no single explanation for the extensive colony losses but that interactions between different stresses are involved. As the presence of Varroa in each colony places an important pressure on bee health, we here address the question of how Varroa contributes to the recent surge in honey bee colony losses

    The impact of parametric noise amplification on long haul transmission throughput

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    Advanced signal processing, such as multi-channel digital back propagation and mid span optical phase conjugation, can compensate for inter channel nonlinear effects in point to point links. However, once such are effects are compensated, the interaction between the signal and noise fields becomes dominant. We will show that this interaction has a direct impact on the signal to noise ratio improvement, observing that ideal optical phase conjugation offers 1.5 dB more performance benefit than DSP based compensation
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