695 research outputs found

    Articulatory Tradeoffs Reduce Acoustic Variability During American English /r/ Production

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    Acoustic and articulatory recordings reveal that speakers utilize systematic articulatory tradeoffs to maintain acoustic stability when producing the phoneme /r/. Distinct articulator configurations used to produce /r/ in various phonetic contexts show systematic tradeoffs between the cross-sectional areas of different vocal tract sections. Analysis of acoustic and articulatory variabilities reveals that these tradeoffs act to reduce acoustic variability, thus allowing large contextual variations in vocal tract shape; these contextual variations in turn apparently reduce the amount of articulatory movement required. These findings contrast with the widely held view that speaking involves a canonical vocal tract shape target for each phoneme.National Institute on Deafness and Other Communication Disorders (1R29-DC02852-02, 5R01-DC01925-04, 1R03-C2576-0l); National Science Foundation (IRI-9310518

    Advancing the link between ocean connectivity, ecological function and management challenges

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    “Ocean connectivity” is a dynamic and rapidly evolving field of research in marine science, partly because there is an increasing demand for information on connectivity that informs effective assessment and management of marine resources. Achieving this will require a better alignment between ocean connectivity tools and developments and the needs and challenges of assessments and conservation. For these reasons, the ICES Journal of Marine Science solicited contributions to the article theme set (TS), “Beyond ocean connectivity.” We briefly summarize the nine articles that appear herein, grouping them into four general topics: methodological advances, population dynamics and assessment implications of connectivity, spatial and management implications, and connectivity in ecosystem processes. We also discuss the challenges facing ocean connectivity research if it is to effectively support advancing fisheries assessment frameworks and integrated ecosystem approaches. We hope that the contributions included in this TS serve to convince managers and fisheries scientists of the need to incorporate results from research on connectivity

    Evaluating the role of quality assessment of primary studies in systematic reviews of cancer practice guidelines

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    BACKGROUND: The purpose of this study was to evaluate the role of study quality assessment of primary studies in cancer practice guidelines. METHODS: Reliable and valid study quality assessment scales were sought and applied to published reports of trials included in systematic reviews of cancer guidelines. Sensitivity analyses were performed to evaluate the relationship between quality scores and pooled odds ratios (OR) for mortality and need for blood transfusion. RESULTS: Results found that that whether trials were classified as high or low quality depended on the scale used to assess them. Although the results of the sensitivity analyses found some variation in the ORs observed, the confidence intervals (CIs) of the pooled effects from each of the analyses of high quality trials overlapped with the CI of the pooled odds of all trials. Quality score was not predictive of pooled ORs studied here. CONCLUSIONS: Had sensitivity analyses based on study quality been conducted prospectively, it is highly unlikely that different conclusions would have been found or that different clinical recommendations would have emerged in the guidelines

    Effect of lighting conditions on zebrafish growth and development

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    In the underwater environment, the properties of light (intensity and spectrum) change rapidly with depth and water quality. In this article, we have described how and to what extent lighting conditions can influence the development, growth, and survival of zebrafish. Fertilized eggs and the corresponding larvae were exposed to different visible light wavelengths (violet, blue, green, yellow, red, and white) in a 12-h light-12-h dark (LD) cycle until 30 days posthatching (dph), when the expression of morphometric parameters and growth (igf1a, igf2a)- and stress-related (crh and pomca) genes were examined. Another group of larvae was raised under constant darkness (DD) until 5 or 10 dph, after which they were transferred to a LD of white light. A third group remained under DD to investigate the effects of light deprivation upon zebrafish development. The results revealed that the hatching rate was highest under blue and violet light, while total length at 30 dph was greatest under blue, white, and violet light. Red light led to reduced feeding activity and poor survival (100% mortality). Larvae raised under constant white light (LL) showed a higher proportion of malformations, as did larvae raised under LD violet light. The expression of growth and stress factors was upregulated in the violet (igf1a, igf2a, pomca, and chr) and blue (igf2a) groups, which is consistent with the higher growth recorded and the higher proportion of malformations detected under the violet light. All larvae kept under DD died before 18 dph, but the survival rates improved in larvae transferred to LD at 5 dph and at 10 dph. In summary, these findings revealed that lighting conditions are crucial factors influencing zebrafish larval development and growth

    Ocean Acidification Disrupts Prey Responses to Predator Cues but Not Net Prey Shell Growth in Concholepas concholepas (loco)

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    Background Most research on Ocean Acidification (OA) has largely focused on the process of calcification and the physiological trade-offs employed by calcifying organisms to support the building of calcium carbonate structures. However, there is growing evidence that OA can also impact upon other key biological processes such as survival, growth and behaviour. On wave-swept rocky shores the ability of gastropods to self-right after dislodgement, and rapidly return to normal orientation, reduces the risk of predation. Methodology/Principal Findings The impacts of OA on this self-righting behaviour and other important parameters such as growth, survival, shell dissolution and shell deposition in Concholepas concholepas (loco) were investigated under contrasting pCO2 levels. Although no impacts of OA on either growth or net shell calcification were found, the results did show that OA can significantly affect self-righting behaviour during the early ontogeny of this species with significantly faster righting times recorded for individuals of C. concholepas reared under increased average pCO2 concentrations (± SE) (716±12 and 1036±14 µatm CO2) compared to those reared at concentrations equivalent to those presently found in the surface ocean (388±8 µatm CO2). When loco were also exposed to the predatory crab Acanthocyclus hassleri, righting times were again increased by exposure to elevated CO2, although self-righting times were generally twice as fast as those observed in the absence of the crab. Conclusions and Significance These results suggest that self-righting in the early ontogeny of C. concholepas will be positively affected by pCO2 levels expected by the end of the 21st century and beginning of the next one. However, as the rate of self-righting is an adaptive trait evolved to reduce lethal predatory attacks, our result also suggest that OA may disrupt prey responses to predators in nature

    Temporal inflection points in decorated pottery: a bayesian refinement of the late formative chronology in the Southern Lake Titicaca Basin, Bolivia

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    The Late Formative period immediately precedes the emergence of Tiwanaku, one of the earliest South American states, yet it is one of the most poorly understood periods in the southern Lake Titicaca Basin (Bolivia). In this article, we refine the ceramic chronology of this period with large sets of dates from eight sites, focusing on temporal inflection points in decorated ceramic styles. These points, estimated here by Bayesian models, index specific moments of change: (1) cal AD 120 (60-170, 95% probability): the first deposition of Kalasasaya red-rimmed and zonally incised styles; (2) cal AD 240 (190-340, 95% probability): a tentative estimate of the final deposition of Kalasasaya zonally incised vessels; (3) cal AD 420 (380-470, 95% probability): the final deposition of Kalasasaya red-rimmed vessels; and (4) cal AD 590 (500-660, 95% probability): the first deposition of Tiwanaku Redwares. These four modeled boundaries anchor an updated Late Formative chronology, which includes the Initial Late Formative phase, a newly identified decorative hiatus between the Middle and Late Formative periods. The models place Qeya and transitional vessels between inflection points 3 and 4 based on regionally consistent stratigraphic sequences. This more precise chronology will enable researchers to explore the trajectories of other contemporary shifts during this crucial period in Lake Titicaca Basin's prehistory.Fil: Marsh, Erik Johnson. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Paleoecología Humana; ArgentinaFil: Roddick, Andrew P.. Mc Master University; CanadáFil: Bruno, Maria C.. Dickinson College; Estados UnidosFil: Smith, Scott C.. Franklin & Marshall College; Estados UnidosFil: Janusek, John W.. Vanderbilt University; Estados UnidosFil: Hastorf, Christine A.. University of California at Berkeley; Estados Unido

    E-learning interventions are comparable to user's manual in a randomized trial of training strategies for the AGREE II

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    <p>Abstract</p> <p>Background</p> <p>Practice guidelines (PGs) are systematically developed statements intended to assist in patient and practitioner decisions. The AGREE II is the revised tool for PG development, reporting, and evaluation, comprised of 23 items, two global rating scores, and a new User's Manual. In this study, we sought to develop, execute, and evaluate the impact of two internet interventions designed to accelerate the capacity of stakeholders to use the AGREE II.</p> <p>Methods</p> <p>Participants were randomized to one of three training conditions. 'Tutorial'--participants proceeded through the online tutorial with a virtual coach and reviewed a PDF copy of the AGREE II. 'Tutorial + Practice Exercise'--in addition to the Tutorial, participants also appraised a 'practice' PG. For the practice PG appraisal, participants received feedback on how their scores compared to expert norms and formative feedback if scores fell outside the predefined range. <it>'</it>AGREE II User's Manual PDF (control condition)'<it>--</it>participants reviewed a PDF copy of the AGREE II only. All participants evaluated a test PG using the AGREE II. Outcomes of interest were learners' performance, satisfaction, self-efficacy, mental effort, time-on-task, and perceptions of AGREE II.</p> <p>Results</p> <p>No differences emerged between training conditions on any of the outcome measures.</p> <p>Conclusions</p> <p>We believe these results can be explained by better than anticipated performance of the AGREE II PDF materials (control condition) or the participants' level of health methodology and PG experience rather than the failure of the online training interventions. Some data suggest the online tools may be useful for trainees new to this field; however, this requires further study.</p
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