309 research outputs found

    Financial Aid and Students' College Decisions: Evidence from the District of Columbia's Tuition Assistance Grant Program

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    The District of Columbia's Tuition Assistance Grant Program (DCTAG), instituted in 1999, allows DC residents to attend public colleges and universities throughout the country at considerably lower in-state tuition rates. We use the sharp decline in the price of public colleges and universities faced by residents of the District of Columbia under DCTAG to estimate the effects of price on students' college application and enrollment decisions. Using a sample of students from nearby large cities as a control group, we find that the number and share of DC residents applying to four-year colleges increased substantially under the program, and students were considerably more likely to apply to colleges that were eligible for the subsidy. Freshmen enrollments of DC residents also increased substantially at eligible institutions, although the effect on overall freshmen enrollments of DC residents was fairly modest, suggesting that in its first year the subsidy had more of an impact on where students chose to attend than on whether they chose to attend college at all.

    Using Subset Log-Likelihoods to Trim Outliers in Gaussian Mixture Models

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    Mixtures of Gaussian distributions are a popular choice in model-based clustering. Outliers can affect parameters estimation and, as such, must be accounted for. Predicting the proportion of outliers correctly is paramount as it minimizes misclassification error. It is proved that, for a finite Gaussian mixture model, the log-likelihoods of the subset models are distributed according to a mixture of beta distributions. An algorithm is then proposed that predicts the proportion of outliers by measuring the adherence of a set of subset log-likelihoods to a beta mixture reference distribution. This algorithm removes the least likely points, which are deemed outliers, until model assumptions are met

    Inequalities in the dental health needs and access to dental services among looked after children in Scotland: a population data linkage study

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    Background: There is limited evidence on the health needs and service access among children and young people who are looked after by the state. The aim of this study was to compare dental treatment needs and access to dental services (as an exemplar of wider health and well-being concerns) among children and young people who are looked after with the general child population. Methods: Population data linkage study utilising national datasets of social work referrals for ‘looked after’ placements, the Scottish census of children in local authority schools, and national health service’s dental health and service datasets. Results: 633 204 children in publicly funded schools in Scotland during the academic year 2011/2012, of whom 10 927 (1.7%) were known to be looked after during that or a previous year (from 2007–2008). The children in the looked after children (LAC) group were more likely to have urgent dental treatment need at 5 years of age: 23%vs10% (n=209/16533), adjusted (for age, sex and area socioeconomic deprivation) OR 2.65 (95% CI 2.30 to 3.05); were less likely to attend a dentist regularly: 51%vs63% (n=5519/388934), 0.55 (0.53 to 0.58) and more likely to have teeth extracted under general anaesthesia: 9%vs5% (n=967/30253), 1.91 (1.78 to 2.04). Conclusions: LAC are more likely to have dental treatment needs and less likely to access dental services even when accounting for sociodemographic factors. Greater efforts are required to integrate child social and healthcare for LAC and to develop preventive care pathways on entering and throughout their time in the care system

    Conserved and unique transcriptional features of pharyngeal arches in the skate (Leucoraja erinacea) and evolution of the jaw

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hirschberger, C., Sleight, V. A., Criswell, K. E., Clark, S. J., & Gillis, J. A. Conserved and unique transcriptional features of pharyngeal arches in the skate (Leucoraja erinacea) and evolution of the jaw. Molecular Biology and Evolution, (2021): msab123, https://doi.org/10.1093/molbev/msab123The origin of the jaw is a long-standing problem in vertebrate evolutionary biology. Classical hypotheses of serial homology propose that the upper and lower jaw evolved through modifications of dorsal and ventral gill arch skeletal elements, respectively. If the jaw and gill arches are derived members of a primitive branchial series, we predict that they would share common developmental patterning mechanisms. Using candidate and RNAseq/differential gene expression analyses, we find broad conservation of dorsoventral patterning mechanisms within the developing mandibular, hyoid and gill arches of a cartilaginous fish, the skate (Leucoraja erinacea). Shared features include expression of genes encoding members of the ventralising BMP and endothelin signalling pathways and their effectors, the joint markers nkx3.2 and gdf5 and pro-chondrogenic transcription factor barx1, and the dorsal territory marker pou3f3. Additionally, we find that mesenchymal expression of eya1/six1 is an ancestral feature of the mandibular arch of jawed vertebrates, while differences in notch signalling distinguish the mandibular and gill arches in skate. Comparative transcriptomic analyses of mandibular and gill arch tissues reveal additional genes differentially expressed along the dorsoventral axis of the pharyngeal arches, including scamp5 as a novel marker of the dorsal mandibular arch, as well as distinct transcriptional features of mandibular and gill arch muscle progenitors and developing gill buds. Taken together, our findings reveal conserved patterning mechanisms in the pharyngeal arches of jawed vertebrates, consistent with serial homology of their skeletal derivatives, as well as unique transcriptional features that may underpin distinct jaw and gill arch morphologies.This work was supported by a Biotechnology and Biological Sciences Research Council Doctoral Training Partnership studentship to CH, by a Wolfson College Junior Research Fellowship and MBL Whitman Early Career Fellowship to VAS, and by a Royal Society University Research Fellowship (UF130182 and URF\R\191007), Royal Society Research Grant (RG140377) and University of Cambridge Sir Isaac Newton Trust Grant (14.23z) to JAG

    A porcine model system of BRCA1 driven breast cancer

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    BRCA1 is a breast and ovarian tumor suppressor. Hereditary mutations in BRCA1 result in a predisposition to breast cancer, and BRCA1 expression is down-regulated in ~30% of sporadic cases. The function of BRCA1 remains poorly understood, but it appears to play an important role in DNA repair and the maintenance of genetic stability. Mouse models of BRCA1 deficiency have been developed in an attempt to understand the role of the gene in vivo. However, the subtle nature of BRCA1 function and the well-known discrepancies between human and murine breast cancer biology and genetics may limit the utility of mouse systems in defining the function of BRCA1 in cancer and validating the development of novel therapeutics for breast cancer. In contrast to mice, pig biological systems and cancer genetics appear to more closely resemble their human counterparts. To determine if BRCA1 inactivation in pig cells promotes their transformation and may serve as a model for the human disease, we developed an immortalized porcine breast cell line and stably inactivated BRCA1 using miRNA. The cell line developed characteristics of breast cancer stem cells and exhibited a transformed phenotype. These results validate the concept of using pigs as a model to study BRCA1 defects in breast cancer and establish the first porcine breast tumor cell line

    Clinical Correlates and Prognostic Significance of the Ventilatory Response to Exercise in Chronic Heart Failure

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    AbstractObjectives. This study sought to investigate the clinical characteristics of patients with chronic heart failure and an increased ventilatory response to exercise and to examine the prognostic usefulness of this response.Background. The ventilatory response to exercise is increased in many patients with chronic heart failure and may be characterized by the regression slope relating minute ventilation to carbon dioxide output (V̇e–V̇co2slope) during exercise.Methods. One hundred seventy-three consecutive patients (155 men; mean [±SD] age 59.8 ± 11.5 years; radionuclide left ventricular ejection fraction [LVEF] 28.4 ± 14.6%) underwent cardiopulmonary exercise testing (peak oxygen consumption 18.5 ± 7.3 ml/kg per min; V̇e–V̇co2slope 34.8 ± 10.6) over a 2-year period. Using 1.96 standard deviations above the mean V̇e–V̇co2slope of 68 healthy age-matched subjects (mean slope 26.3 ± 4.1), we defined a high ventilatory response to exercise as a slope >34.Results. Eighty-three patients (48%) had an increased V̇e–V̇co2slope (mean 43.1 ± 8.9). There was a difference in age (62.2 vs. 57.3 years, p = 0.005), New York Heart Association functional class (2.9 vs. 2.1, p < 0.001), LVEF (24.7 vs. 31.9%, p = 0.0016), peak oxygen consumption (14.9 vs. 21.7 ml/kg per min, p < 0.0001) and radiographic cardiothoracic ratio (0.58 vs. 0.55, p = 0.002) between these patients and those with a normal slope. In the univariate Cox proportional hazards model, the V̇e–V̇co2slope was an important prognostic factor (p < 0.0001). In the multivariate Cox analyses using several variables (age, peak oxygen consumption, V̇e–V̇co2slope and LVEF), the V̇e–V̇co2slope gave additional prognostic information (p = 0.018) beyond peak oxygen consumption (p = 0.022). Kaplan-Meier survival curves at 18 months demonstrated a survival rate of 95% in patients with a normal V̇e–V̇co2slope compared with 69% in those with a high slope (p < 0.0001).Conclusions. A high V̇e–V̇co2slope selects patients with more severe heart failure and is an independent prognostic marker. The V̇e–V̇co2slope may be used as a supplementary index in the assessment of patients with chronic heart failure.(J Am Coll Cardiol 1997;29:1585–90

    Physiotherapy for adults with joint hypermobility syndrome: A pilot randomised controlled trial

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    Background: Joint Hypermobility Syndrome (JHS) is a heritable disorder associated with laxity and pain in multiple joints. Physiotherapy is the mainstay of treatment but there is little research investigating its effectiveness. The aim of this study was therefore to conduct a pilot randomised controlled trial (RCT) to determine the feasibility of conducting a future definitive RCT. Methods: A comprehensive physiotherapy intervention was developed in conjunction with patients and healthcare professionals. It was then piloted and refined on the basis of patient and physiotherapist feedback. A parallel two-arm pilot RCT in two UK secondary care NHS Trusts compared 'Advice' against 'Advice & Physiotherapy'. Inclusion criteria were: >16 years, a diagnosis of JHS, and no other musculoskeletal conditions causing pain. The Advice intervention was a one-off session, supplemented by advice booklets from the Hypermobility Syndromes Association and Arthritis Research UK. All patients could ask questions specific to their circumstances and received tailored advice. Participants were then randomly allocated to 'Advice' (no further advice or physiotherapy) or 'Advice & Physiotherapy' (an additional six 30 minute sessions over 4 months). The Physiotherapy intervention was supported by a patient handbook and delivered on a one-to-one patient-therapist basis. It aimed to increase patients’ physical activity through developing knowledge, understanding and skills to better manage their condition. The primary outcome related to the feasibility of conducting a future definitive RCT. Qualitative interviews with patients and physiotherapists therefore formed a major component of data collection. Secondary outcomes included clinical measures (physical function, pain, global status, self-reported joint count, quality of life, exercise self-efficacy and adverse events); resource use (to estimate cost-effectiveness); and an estimate of the value of information from a future RCT. Outcomes were recorded at baseline, 4 months (at the end of physiotherapy) and 7 months (3 months following physiotherapy). Results: A total of n=29 participants were recruited to the pilot RCT. Recruitment was challenging, primarily due to a perceived lack of equipoise between Advice and Physiotherapy. The qualitative evaluation provided very clear guidance to inform a future RCT, including enhancement of the Advice intervention. Some patients reported that the Advice intervention was useful and the Physiotherapy intervention was evaluated very positively. The rate of return of questionnaires was low within the Advice group but reasonable in the Physiotherapy group. The Physiotherapy intervention showed evidence of promise in terms of primary and secondary clinical outcomes. The Advice arm experienced more adverse events. The value of information estimate indicated the potential for high value from a future RCT. Conclusion: A future definitive RCT of physiotherapy for JHS seems feasible, although the Advice intervention should be made more robust to address perceived equipoise and subsequent attrition
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