124 research outputs found

    B stars as a diagnostic of star-formation at low and high redshift

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    We have extended the evolutionary synthesis models by Leitherer et al. (1999b) by including a new library of B stars generated from the IUE high-dispersion spectra archive. We present the library and show how the stellar spectral properties vary according to luminosity classes and spectral types. We have generated synthetic UV spectra for prototypical young stellar populations varying the IMF and the star formation law. Clear signs of age effects are seen in all models. The contribution of B stars in the UV line spectrum is clearly detected, in particular for greater ages when O stars have evolved. With the addition of the new library we are able to investigate the fraction of stellar and interstellar contributions and the variation in the spectral shapes of intense lines. We have used our models to date the spectrum of the local super star cluster NGC1705-1. Photospheric lines of CIII1247, SiIII1417, and SV1502 were used as diagnostics to date the burst of NGC 1705-1 at 10 Myr. We have selected the star-forming galaxy 1512-cB58 as a first application of the new models to high-z galaxies. This galaxy is at z=2.723, it is gravitationally lensed, and its high signal-to-noise Keck spectrum show features typical of local starburst galaxies, such as NGC 1705-1. Models with continuous star formation were found to be more adequate for 1512-cB58 since there are spectral features typical of a composite stellar population of O and B stars. A model with Z =0.4Z_solar and an IMF with alpha=2.8 reproduces the stellar features of the 1512-cB58 spectrum.Comment: 23 pages with figures, see http://sol.stsci.edu/~demello/welcomeb.htm

    Effectiveness of semantic therapy for word-finding difficulties in pupils with persistent language impairments: a randomized control trial

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    BACKGROUND: Word-finding difficulties (WFDs) in children have been hypothesized to be caused at least partly by poor semantic knowledge. Therefore, improving semantic knowledge should decrease word-finding errors. Previous studies of semantic therapy for WFDs are inconclusive. AIMS: To investigate the effectiveness of semantic therapy for secondary school-aged pupils with WFDs using a randomized control trial with blind assessment. METHODS & PROCEDURES: Fifteen participants with language impairments and WFDs (aged 9;11–15;11) were randomly assigned to a therapy versus waiting control group. In Phase 1 the therapy group received two 15-min semantic therapy sessions per week for 8 weeks with their usual speech and language therapist. Therapy for each participant targeted words from one of three semantic categories (animals, food, clothes). All participants were tested pre- and post-phase 1 therapy on the brief version of the Test of Adolescent Word Finding (TAWF), semantic fluency and the Test of Word Finding in Discourse (TWFD). In Phase 2 the waiting control group received the same therapy as the original therapy group, which received therapy targeted at other language areas. Testing after Phase 2 aimed to establish whether the waiting control group made similar progress to the original therapy group and whether the original therapy group maintained any gains. OUTCOMES & RESULTS: The original therapy group made significant progress in standard scores on the TAWF (d= 0.94), which was maintained 5 months later. However, they made no progress on the semantic fluency or discourse tests. Participants in the waiting control group did not make significant progress on the TAWF in Phase 1 when they received no word-finding therapy. However, after Phase 2, when they received the therapy, they also made significant progress (d= 0.81). The combined effect of therapy over the two groups was d= 1.2. The mean standard scores on the TAWF were 67 pre-therapy and 77 post-therapy. CONCLUSIONS & IMPLICATIONS: Four hours of semantic therapy on discrete semantic categories led to significant gains on a general standardized test of word finding, enabling the participants to begin to close the gap between their performance and that of their typically developing peers. These gains were maintained after 5 months. A small amount of therapy can lead to significant gains even with secondary aged pupils with severe language difficulties. However, further studies are needed to find ways of improving word-finding abilities in discourse

    A Multiwavelength Analysis of the Strong Lensing Cluster RCS 022434-0002.5 at z=0.778

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    We present the results of two (101 ks total) Chandra observations of the z=0.778 optically selected lensing cluster RCS022434-0002.5, along with weak lensing and dynamical analyses of this object. An X-ray spectrum extracted within R(2500) (362 h(70)^(-1) kpc) results in an integrated cluster temperature of 5.1 (+0.9,-0.5) keV. The surface brightness profile of RCS022434-0002.5 indicates the presence of a slight excess of emission in the core. A hardness ratio image of this object reveals that this central emission is primarily produced by soft X-rays. Further investigation yields a cluster cooling time of 3.3 times 10^9 years, which is less than half of the age of the universe at this redshift given the current LCDM cosmology. A weak lensing analysis is performed using HST images, and our weak lensing mass estimate is found to be in good agreement with the X-ray determined mass of the cluster. Spectroscopic analysis reveals that RCS022434-0002.5 has a velocity dispersion of 900 +/- 180 km/s, consistent with its X-ray temperature. The core gas mass fraction of RCS022434-0002.5 is, however, found to be three times lower than expected universal values. The radial distribution of X-ray point sources within R(200) of this cluster peaks at ~0.7 R(200), possibly indicating that the cluster potential is influencing AGN activity at that radius. Correlations between X-ray and radio (VLA) point source positions are also examined.Comment: 32 pages, 9 figures. Accepted for publication in The Astrophysical Journa

    Supporting adjective learning by children with Developmental Language Disorder: Enhancing metalinguistic approaches.

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    BACKGROUND: Adjectives are essential for communication, conceptual development and academic success. However, they are semantically and syntactically complex and can be particularly challenging for children with Developmental Language Disorder (DLD). Surprisingly, language interventions have not typically focused on this important word class. AIMS: (1) To provide a supportive and accessible primer on adjectives for practitioners; (2) to explore how the SHAPE CODINGTM system can be adapted to support adjective learning in DLD; and (3) to provide practical recommendations on how to support adjective learning in clinical practice and education. METHODS/PROCEDURE: We synthesise linguistic and psychological research on adjective semantics, clinical insights into DLD and pedagogical practice supporting this population. MAIN CONTRIBUTION: We address the lack of specific training in the nature and acquisition of adjectives for speech and language therapists (SLTs) by providing an accessible primer. We also provide an innovative guide detailing how an established metalinguistic intervention might be adapted to support adjective learning. CONCLUSIONS/IMPLICATIONS: Without targeted support for adjective learning, the communicative potential of children with DLD is compromised. Our recommendations can be used across a range of therapeutic and educational contexts to guide SLTs and teaching staff in developing practice in this area. WHAT THIS PAPER ADDS: What is already known on the subject Adjectives are an essential word class needed for effective communication. They are also vital to successfully achieve academic objectives across all curriculum areas. For example, most subjects require children to be able to describe, evaluate, compare and discriminate different events, objects or techniques. Children with Developmental Language Disorder (DLD) have deficits in various domains of language that can affect adjective learning and use. What this paper adds to existing knowledge Despite the importance of adjectives, speech and language therapists (SLTs) and other professionals supporting language development rarely receive specific training regarding their structure and meanings, and how to teach and support their use. This article provides an accessible primer on the many subtypes of adjectives and how these behave syntactically and semantically. It explores how adjective teaching could be enhanced for children with DLD by adapting an established metalinguistic technique and provides practical recommendations for implementing this approach. What are the potential or actual clinical implications of this work? By raising awareness of the complexities of adjectives and providing strategies to support their acquisition by children with DLD, this article will enable SLTs and teaching staff to improve their understanding and practice in this area and, with further research, to develop robust, effective interventions for children with DLD. This will contribute to enhancing the long-term academic, social and employment success of children with DLD

    The association of fish consumption and its urinary metabolites with cardiovascular risk factors: The International Study of Macro-/Micronutrients and Blood Pressure (INTERMAP)

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    Background Results from observational studies regarding associations between fish (including shellfish) intake and cardiovascular disease risk factors, including blood pressure (BP) and BMI, are inconsistent. Objective To investigate associations of fish consumption and associated urinary metabolites with BP and BMI in free-living populations. Methods We used cross-sectional data from the International Study of Macro-/Micronutrients and Blood Pressure (INTERMAP), including 4680 men and women (40–59 y) from Japan, China, the United Kingdom, and United States. Dietary intakes were assessed by four 24-h dietary recalls and BP from 8 measurements. Urinary metabolites (2 timed 24-h urinary samples) associated with fish intake acquired from NMR spectroscopy were identified. Linear models were used to estimate BP and BMI differences across categories of intake and per 2 SD higher intake of fish and its biomarkers. Results No significant associations were observed between fish intake and BP. There was a direct association with fish intake and BMI in the Japanese population sample (P trend = 0.03; fully adjusted model). In Japan, trimethylamine-N-oxide (TMAO) and taurine, respectively, demonstrated area under the receiver operating characteristic curve (AUC) values of 0.81 and 0.78 in discriminating high against low fish intake, whereas homarine (a metabolite found in shellfish muscle) demonstrated an AUC of 0.80 for high/nonshellfish intake. Direct associations were observed between urinary TMAO and BMI for all regions except Japan (P < 0.0001) and in Western populations between TMAO and BP (diastolic blood pressure: mean difference 1.28; 95% CI: 0.55, 2.02 mmHg; P = 0.0006, systolic blood pressure: mean difference 1.67; 95% CI: 0.60, 2.73 mmHg; P = 0.002). Conclusions Urinary TMAO showed a stronger association with fish intake in the Japanese compared with the Western population sample. Urinary TMAO was directly associated with BP in the Western but not the Japanese population sample. Associations between fish intake and its biomarkers and downstream associations with BP/BMI appear to be context specific. INTERMAP is registered at www.clinicaltrials.gov as NCT00005271

    Editorial Perspective: Speaking up for developmental language disorder - the top 10 priorities for research

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    Developmental language disorder (DLD) is one of the most common neurodevelopmental conditions, yet is chronically underserved, with far fewer children receiving clinical services than expected from prevalence estimates, and very little research attention relative to other neurodevelopmental conditions of similar prevalence and severity. This editorial describes a research priority-setting exercise undertaken by the Royal College of Speech and Language Therapists, which aims to redress this imbalance. From consultations with researchers, practitioners and individuals with lived experience, 10 research priorities emerge. Our goal is to share these priorities with the wider research community, to raise awareness and encourage research collaboration to improve outcomes for young people with DLD

    An ISOCAM survey through gravitationally lensing galaxy clusters

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    ISOCAM was used to perform a deep survey through three gravitationally lensing clusters of galaxies. Nearly seventy sq. arcmin were covered over the clusters A370, A2218 and A2390. We present maps and photometry at 6.7 & 14.3 microns, showing a total of 145 mid-IR sources and the associated source counts. The 15 micron counts reach the faintest level yet recorded. All sources have counterparts in the optical or near-IR. Models of the clusters were used to correct for the effects of lensing, which increases the sensitivity of the survey. Seven of fifteen SCUBA sources were detected at 15 microns. Five have redshift between 0.23 & 2.8, with a median of 0.9. The field sources were counted to a lensing-corrected sensitivity of 30 microJy at 15 microns, and 14 microJy at 7 microns. The counts, corrected for completeness, contamination by cluster sources and lensing, confirm and extend findings of an excess by a factor of ten in the 15 micron population with respect to source models with no evolution. Source redshifts are mostly between 0.4 and 1.5. For the counts at 7 microns, integrating from 14 microJy to 460 microJy, we resolve 0.49+/-0.2 nW.m^(-2).sr^(-1) of the infrared background light (IBL) into discrete sources. At 15 microns we include the counts from other ISOCAM surveys to integrate from 30 microJy to 50 mJy, two to three times deeper than unlensed surveys, to resolve 2.7+/-0.62 nW.m^(-2).sr^(-1) of the IBL. These values are 10% and 55%, respectively, of the upper limit to the IBL, derived from photon-photon pair production of the TeV gamma rays from BL-Lac sources on the IBL photons. However, recent detections of TeV gamma rays from the z=0.129 BL Lac H1426+428 suggest that the 15 micron background reported implies substantial absorption of TeV photons from that source.Comment: 35 pages, 17 figures, to appear in Astronomy and Astrophysics, full paper with high-resolution figures available at http://www.iso.vilspa.esa.es/science/pub/2003

    Effectiveness of 1:1 speech and language therapy for older children with (developmental) language disorder

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    BACKGROUND: Evidence of the effectiveness of therapy for older children with (developmental) language disorder (DLD), and particularly those with receptive language impairments, is very limited. The few existing studies have focused on particular target areas, but none has looked at a whole area of a service. AIMS: To establish whether for students with (developmental) language disorder attending a specialist school, 1:1 intervention with an SLT during one school term improves performance on targeted areas, compared with untreated control areas. Also, to investigate whether gender, receptive language status, autism spectrum disorder (ASD) status, or educational Key Stage affected their response to this intervention. METHODS & PROCEDURES: Seventy-two students (aged 9–17 years, 88% of whom had receptive language impairments) and all speech and language therapists (SLTs) in our specialist school for children with Language Disorder, most of whom have DLD participated in this study over one school term. During this term, the SLTs devised pre- and post-therapy measures for every student for each target they planned to treat 1:1. In addition, for each target area, a control measure was devised. The targets covered a wide range of speech, language and communication areas, both receptive and expressive. Post-therapy tests were administered ‘blind’. OUTCOMES & RESULTS: During the term, SLTs and students worked 1:1 on 120 targets, the majority in the areas of expressive and receptive language. Targets and controls did not differ pre-therapy. Significant progress was seen both on targets (d = 1.33) and controls (d = 0.36), but the targeted areas improved significantly more than the controls with a large and clinically significant effect size (d = 1.06). There was no effect of language area targeted (targets improved more than their controls for all areas). Participants with versus those without receptive language difficulties, co-occurring ASD diagnosis or participants in different educational Key Stages did not differ significantly in terms of the progress they made on target areas. CONCLUSIONS AND IMPLICATIONS: Direct 1:1 intervention with an SLT can be effective for all areas of language for older children with (D)LD, regardless of their gender, receptive language or ASD status, or age. This adds to the relatively limited evidence base regarding the effectiveness of direct SLT intervention for school-aged children with (D)LD and for children with receptive language impairments. If direct 1:1 intervention can be effective with this hard-to-treat group, it may well also be effective with younger children with (D)LD. Thus, direct SLT services should be available for school-aged children with (D)LD, including older children and adolescents with pervasive difficulties
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