1,809 research outputs found

    Microlensing Constraints on Broad Absorption and Emission Line Flows in the Quasar H1413+117

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    We present new integral field spectroscopy of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to visible rest-frame spectral range. We observe strong microlensing signatures in lensed image D, and we use this microlensing to simultaneously constrain both the broad emission and broad absorption line gas. By modeling the lens system over the range of probable lensing galaxy redshifts and using on a new argument based on the wavelength-independence of the broad line lensing magnifications, we determine that there is no significant broad line emission from smaller than ~20 light days. We also perform spectral decomposition to derive the intrinsic broad emission line (BEL) and continuum spectrum, subject to BAL absorption. We also reconstruct the intrinsic BAL absorption profile, whose features allow us to constrain outflow kinematics in the context of a disk-wind model. We find a very sharp, blueshifted onset of absorption of 1,500 km/s in both C IV and N V that may correspond to an inner edge of a disk-wind's radial outflow. The lower ionization Si IV and Al III have higher-velocity absorption onsets, consistent with a decreasing ionization parameter with radius in an accelerating outflow. There is evidence of strong absorption in the BEL component which indicates a high covering factor for absorption over two orders of magnitude in outflow radius.Comment: 29 pages, 8 figure

    Distribution and composition of the lysis cassette of Lactococcus lactis phages and functional analysis of bacteriophage ul36 holin

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    The bacteriophage lysis cassette, which comprises a lysin and a holin gene, was analyzed in 18 Lactococcus lactis phages. A muramidase motif was found in the lysins of c2-like phages, while an amidase motif was observed in the lysins of 936-like phages. Both amidase and muramidase types were detected among the P335 phages. The P335 lysins were separated into three groups based on amino acid sequence identity. A class I holin was recognized in 936-like and c2-like phages, whereas P335-like phages possess class II holins. The P335 holins were further divided into four groups based on sequence identity. Only the holins of 936-like phages contained putative dual-start motifs. The unusual lysis cassette of the highly virulent P335-like phage ul36 contains a unique holin (orf74B) upstream of a lysin which is present in several other P335-like phages. Using the λΔSthf system, we demonstrated that gpORF74B induces cell lysis at the same time as λΔSthf::S105, the effector of λ lysis. Transcriptional analysis of ul36 lysis cassette showed that first transcripts are detected 35 min after infection of L. lactis cells. The lysis clock of phage ul36 appears to be controlled by the late expression of the holin and lysin gene

    Trilingual conversations: a window into multicompetence

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    A recurrent theme in the literature on trilingual language use is the question of whether there is a specific “trilingual competence.” In this paper we consider this question in the light of codeswitching patterns in two dyadic trilingual conversations between a mother and daughter conducted in (Lebanese) Arabic, French, and English. Quantitative and qualitative analysis of codeswitching in both conversants shows that, despite the fact that both subjects are fluent in all three languages, uses of switching are significantly different for mother and daughter across a number of features, including relative frequency of different switch types, and the incidence of hybrid constructions involving items from two or more languages. The subjects appear to display qualitatively distinct profiles of competence in the trilingual mode. This in turn leads to the conclusion that the facts of trilingual language use are best characterized in terms of “multicompetence” (Cook, 1991). The paper concludes with some further reflections on the uniqueness of trilingual language use (an “old chestnut” in trilingualism research, cf. Klein, 1995)

    Incontinence : stress urinary incontinence treatment—surgery first?

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    A randomized trial involving 460 women with stress urinary incontinence compared physiotherapy with midurethral-sling surgery. We question whether the results, showing higher rates of improvement and cure for surgery than for physiotherapy, should change best practice and clinical practice guideline recommendations

    Corporations - Dissolution - Effect on Federal Criminal Prosecution Against Corporation

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    Defendant corporation was prosecuted along with its officers .and employees for submitting false statements on FHA insured loans and for conspiracy. After return of indictment the corporation was voluntarily dissolved under Texas law. The corporation\u27s motion to dismiss the indictment on the ground that dissolution abated the prosecution was overruled. On appeal, held, affirmed. Article 1388 of the Texas civil statutes which constitutes the president and directors trustees to settle the affairs of a dissolved corporation and to maintain or defend judicial proceedings, continues the corporation in existence for the purpose of defending federal criminal proceedings. Alamo Fence Company of Houston v. United States, (5th Cir. 1957) 240 F. (2d) 179

    Design and feasibility testing of a novel group intervention for young women who binge drink in groups

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    BackgroundYoung women frequently drink alcohol in groups and binge drinking within these natural drinking groups is common. This study describes the design of a theoretically and empirically based group intervention to reduce binge drinking among young women. It also evaluates their engagement with the intervention and the acceptability of the study methods.MethodsFriendship groups of women aged 18–35 years, who had two or more episodes of binge drinking (>6 UK units on one occasion; 48g of alcohol) in the previous 30 days, were recruited from the community. A face-to-face group intervention, based on the Health Action Process Approach, was delivered over three sessions. Components of the intervention were woven around fun activities, such as making alcohol free cocktails. Women were followed up four months after the intervention was delivered. Results The target of 24 groups (comprising 97 women) was recruited. The common pattern of drinking was infrequent, heavy drinking (mean consumption on the heaviest drinking day was UK 18.1 units). Process evaluation revealed that the intervention was delivered with high fidelity and acceptability of the study methods was high. The women engaged positively with intervention components and made group decisions about cutting down. Twenty two groups set goals to reduce their drinking, and these were translated into action plans. Retention of individuals at follow up was 87%.ConclusionsThis study successfully recruited groups of young women whose patterns of drinking place them at high risk of acute harm. This novel approach to delivering an alcohol intervention has potential to reduce binge drinking among young women. The high levels of engagement with key steps in the behavior change process suggests that the group intervention should be tested in a full randomised controlled trial

    The ionized gas in the central region of NGC 5253: 2D mapping of the physical and chemical properties

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    ABRIDGED: NGC5253 was previously studied by our group with the aim to elucidate in detail the starburst interaction processes. Some open issues regarding the 2D structure of the main properties of the ionized gas remain to be addressed. Using IFS data obtained with FLAMES, we derived 2D maps for different tracers of electron density (n_e), electron temperature (T_e) and ionization degree. The maps for n_e as traced by several line ratios are compatible with a 3D stratified view of the nebula with the highest n_e in the innermost layers and a decrease of n_e outwards. To our knowledge, this is the first time that a T_e map based on [SII] lines for an extragalactic object is presented. The joint interpretation of our two T_e maps is consistent with a T_e structure in 3D with higher temperatures close to the main ionizing source surrounded by a colder and more diffuse component. The highest ionization degree is found at the peak of emission for the gas with relatively high ionization in the main GHIIR and lower ionization degree delineating the more extended diffuse component. Abundances for O, Ne and Ar are constant over the mapped area within <0.1 dex. The mean 12+log(O/H) is 8.26 while the relative abundances of log(N/O), log(Ne/O) and log(Ar/O) were \sim-1.32, -0.65 and -2.33, respectively. There are two locations with enhanced N/O. The first (log(N/O)\sim-0.95) is associated to two super star clusters. The second (log(N/O)\sim-1.17), reported here for the first time, is associated to two moderately massive (2-4x10^4 M_sun) and relatively old (\sim10 Myr) clusters. A comparison of the N/O map with those produced by strong line methods supports the use of N2O2 over N2S2 in the search for chemical inhomogeneities within a galaxy. The results on the localized nitrogen enhancement were used to compile and discuss the factors that affect the complex relationship between Wolf-Rayet stars and N/O excess.Comment: 16 pages, 14 figures, accepted for publication in A&

    Horizontal DNA transfer mechanisms of bacteria as weapons of intragenomic conflict

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    Horizontal DNA transfer (HDT) is a pervasive mechanism of diversification in many microbial species, but its primary evolutionary role remains controversial. Much recent research has emphasised the adaptive benefit of acquiring novel DNA, but here we argue instead that intragenomic conflict provides a coherent framework for understanding the evolutionary origins of HDT. To test this hypothesis, we developed a mathematical model of a clonally descended bacterial population undergoing HDT through transmission of mobile genetic elements (MGEs) and genetic transformation. Including the known bias of transformation toward the acquisition of shorter alleles into the model suggested it could be an effective means of counteracting the spread of MGEs. Both constitutive and transient competence for transformation were found to provide an effective defence against parasitic MGEs; transient competence could also be effective at permitting the selective spread of MGEs conferring a benefit on their host bacterium. The coordination of transient competence with cell-cell killing, observed in multiple species, was found to result in synergistic blocking of MGE transmission through releasing genomic DNA for homologous recombination while simultaneously reducing horizontal MGE spread by lowering the local cell density. To evaluate the feasibility of the functions suggested by the modelling analysis, we analysed genomic data from longitudinal sampling of individuals carrying Streptococcus pneumoniae. This revealed the frequent within-host coexistence of clonally descended cells that differed in their MGE infection status, a necessary condition for the proposed mechanism to operate. Additionally, we found multiple examples of MGEs inhibiting transformation through integrative disruption of genes encoding the competence machinery across many species, providing evidence of an ongoing "arms race." Reduced rates of transformation have also been observed in cells infected by MGEs that reduce the concentration of extracellular DNA through secretion of DNases. Simulations predicted that either mechanism of limiting transformation would benefit individual MGEs, but also that this tactic's effectiveness was limited by competition with other MGEs coinfecting the same cell. A further observed behaviour we hypothesised to reduce elimination by transformation was MGE activation when cells become competent. Our model predicted that this response was effective at counteracting transformation independently of competing MGEs. Therefore, this framework is able to explain both common properties of MGEs, and the seemingly paradoxical bacterial behaviours of transformation and cell-cell killing within clonally related populations, as the consequences of intragenomic conflict between self-replicating chromosomes and parasitic MGEs. The antagonistic nature of the different mechanisms of HDT over short timescales means their contribution to bacterial evolution is likely to be substantially greater than previously appreciated

    Inquiry Based Learning from the Learner’s Point of View: A Teacher Candidate’s Success Story

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    The goal of this paper is to review current research on Inquiry Based Learning (IBL) and shed some light, from a student\u27s perspective, on the challenges and rewards of this pedagogy. The first part of the article provides an extensive review of the literature on IBL. The second part focuses on one student\u27s experiences in an IBL classroom. In particular, a graduate secondary mathematics student reflects upon his experiences in a college mathematics class where the instructor implemented an Inquiry Based Learning model. His experience is validated by current research on IBL educational methodology which structures the classroom environment for student centered learning. This student reported increased critical thinking skills, higher levels of motivation and engagement, and more retention of content than in other mathematics courses taken. Furthermore, this student believes that he was more invested in his learning, experienced improved conceptual understanding of content, and had higher levels of confidence in mathematics as a result of the IBL experience. As a preservice teacher candidate, he hopes to integrate IBL practices into his future teaching career to improve student learning
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