1,097 research outputs found
Detailed temporal structure of communication networks in groups of songbirds
This work was supported by EPSRC Early Career research fellowship EP/L020505/1
The end of free college in England: implications for quality, enrolments and equity
Despite increasing financial pressures on higher education systems throughout the world, many governments remain resolutely opposed to the introduction of tuition fees, and some countries and states where tuition fees have been long established are now reconsidering free higher education. This paper examines the consequences of charging tuition fees on university quality, enrolments, and equity. To do so, we study the English higher education system which has, in just two decades, moved from a free college system to one in which tuition fees are among the highest in the world. Our findings suggest that England’s shift has resulted in increased funding per head, rising enrolments, and a narrowing of the participation gap between advantaged and disadvantaged students. In contrast to other systems with high tuition fees, the English system is distinct in that its income-contingent loan system keeps university free at the point of entry, and provides students with comparatively generous assistance for living expenses. We conclude that tuition fees, at least in the English case supported their goals of increasing quality, quantity, and equity in higher educatio
Probabilistic expert systems for handling artifacts in complex DNA mixtures
This paper presents a coherent probabilistic framework for taking account of allelic dropout, stutter bands and silent alleles when interpreting STR DNA profiles from a mixture sample using peak size information arising from a PCR analysis. This information can be exploited for evaluating the evidential strength for a hypothesis that DNA from a particular person is present in the mixture. It extends an earlier Bayesian network approach that ignored such artifacts. We illustrate the use of the extended network on a published casework example
Monitoring serum insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), IGF-I/IGFBP-3 molar ratio and leptin during growth hormone treatment for disordered growth
OBJECTIVE: Serum IGF-I levels are monitored during
GH replacement treatment in adults with GH defi-
ciency (GHD) to guide GH dose adjustment and to
minimize occurrence of GH-related side-effects. This
is not routine practice in children treated with GH. The
aim of this study was to evaluate changes in (1) serum
IGF-I, IGFBP-3 and IGF-I/IGFBP-3 molar ratio, and (2)
serum leptin, an indirect marker of GH response,
during the first year of GH treatment in children with
disordered growth.
DESIGN: An observational prospective longitudinal
study with serial measurements at five time points
during the first year of GH treatment was carried out.
Each patient served as his/her own control.
PATIENTS The study included 31 patients, grouped
as (1) GHD (n=20) and (2) non-GHD (Turner syndrome
n=7; Noonan syndrome n=4), who had not previously
received GH treatment.
MEASUREMENTS: Serum IGF-I, IGFBP-3 and leptin
levels were measured before treatment and after
6 weeks, 3 months, 6 months and 12 months of GH
treatment, with a mean dose of 0.5 IU/kg/wk in GHD
and 0.7 IU/kg/wk in non-GHD groups. IGF-I, IGFBP-3
and the calculated IGF-I/IGFBP-3 molar ratio were
expressed as SD scores using reference values from
the local population.
RESULTS: In the GHD group, IGF-I SDS before treatment was lower compared with the non-GHD (-5.4 ± 2.5 vs. -1.8 ± 1.0; P < 0.001). IGF-I (-1.8 SDS ± 2.2) and IGFBP-3 (-1.1 SDS ± 0.6) levels and their molar ratios were highest at 6 weeks and remained relatively constant thereafter. In the non-GHD group, IGF-I levels increased throughout the year and were maximum at 12 months (0.3 SDS ± 1.4) while IGFBP-3 (1.1 SDS ± 0.9) and IGF-I/IGFBP-3 molar ratio peaked at 6 months. In both groups, IGF-I SDS and IGF-I/IGFBP-3 during treatment correlated with the dose of GH expressed as IU/m2/week (r-values 0.77 to 0.89; P = 0.005) but not as IU/kg/week. Serum leptin levels decreased significantly during GH treatment in the GHD (median before treatment 4.0 g/l; median after 12 months treatment 2.4 g/l; P = 0.02) but not the non-GHD (median before treatment 3.0 g/l; median after 12 months treatment 2.6 g/l). In the GHD group, serum leptin before treatment correlated with 12 month change in height SDS (r = 0.70, P = 0.02).
CONCLUSIONS: The pattern of IGF-I, IGFBP-3 and
their molar ratio during the first year of GH treatment
differed between the GHD and non-GHD groups. Calculation
of GH dose by surface area may be preferable
to calculating by body weight. As a GH dose-dependent
increase in serum IGF-I and IGF-I/IGFBP-3 may
be associated with adverse effects, serum IGF-I and
IGFBP-3 should be monitored routinely during longterm
GH treatment. Serum leptin was the only variable
that correlated with first year growth response in
GHD
Strangers in paradise”?: Working-class students in elite universities.
AB STRACT This article draws on case studies of nine working-class students at Southern, an elite university. 1 It attempts to understand the complexities of identities in flux through Bourdieu's notions of habitus and field. Bourdieu (1990a) argues that when an individual encounters an unfamiliar field, habitus is transformed. He also writes of how the movement of habitus across new, unfamiliar fields results in 'a habitus divided against itsel
Estimation of Parameters in DNA Mixture Analysis
In Cowell et al. (2007), a Bayesian network for analysis of mixed traces of
DNA was presented using gamma distributions for modelling peak sizes in the
electropherogram. It was demonstrated that the analysis was sensitive to the
choice of a variance factor and hence this should be adapted to any new trace
analysed. In the present paper we discuss how the variance parameter can be
estimated by maximum likelihood to achieve this. The unknown proportions of DNA
from each contributor can similarly be estimated by maximum likelihood jointly
with the variance parameter. Furthermore we discuss how to incorporate prior
knowledge about the parameters in a Bayesian analysis. The proposed estimation
methods are illustrated through a few examples of applications for calculating
evidential value in casework and for mixture deconvolution
Determinants of carotid microembolization
AbstractPurpose: Earlier studies have highlighted risk factors for perioperative stroke after carotid endarterectomy, such as female sex, preoperative symptoms, and cerebral infarction. In this study, we investigated the relationship between these factors and perioperative microembolization. Methods: A total of 235 patients were entered in the study at two centers. Transcranial Doppler ultrasound scanning was possible in 190 patients (81%) and was performed for 1 hour preoperatively and continuously intraoperatively as a means of detecting microemboli and monitoring mean middle cerebral artery velocity. The findings of transcranial Doppler ultrasound scanning were related to perioperative risk factors by means of univariate analysis. Results: Microemboli were detected in 28 (15%), 79 (42%), and 98 (52%) patients preoperatively, during carotid artery dissection, and after closure of the artery, respectively. Having 10 or more emboli after carotid artery closure was more common in women (P =.04) and in patients with symptomatic carotid artery disease (P =.04) and was demonstrated in three of the six patients who had a perioperative stroke. These three patients also had preoperative evidence of cerebral infarction and an intraoperative middle cerebral artery velocity less than 40 cm/s. Conclusion: In this study, perioperative microembolization was more common in women and patients with symptomatic carotid artery disease. These findings may explain the increased risk of carotid surgery in these patients. (J Vasc Surg 2001;34:1060-4.
Non-parametric paired two-sample tests for censored survival data incorporating longitudinal covariate information
In this manuscript, we present non-parametric two-sample tests for paired censored survival data incorporating longitudinal covariate information. These tests take advantage of information collected at baseline and post-baseline to provide efficiency gains when censoring is uninformative. Additionally, these methods adjust for potential bias from informative censoring that is captured by the baseline and longitudinal covariates. Finite sample properties are investigated with simulation, and we illustrate methodology with an example from the Early Treatment Diabetic Retinopathy Study. Copyright © 2004 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55815/1/1888_ftp.pd
Turbulent Convection in Stellar Interiors. II. The Velocity Field
We analyze stellar convection with the aid of 3D hydrodynamic simulations,
introducing the turbulent cascade into our theoretical analysis. We devise
closures of the Reynolds-decomposed mean field equations by simple physical
modeling of the simulations (we relate temperature and density fluctuations via
coefficients); the procedure (CABS, Convection Algorithms Based on Simulations)
is terrestrially testable and is amenable to systematic improvement. We develop
a turbulent kinetic energy equation which contains both nonlocal and time
dependent terms, and is appropriate if the convective transit time is shorter
than the evolutionary time scale. The interpretation of mixing-length theory
(MLT) as generally used in astrophysics is incorrect; MLT forces the mixing
length to be an imposed constant. Direct tests show that the damping associated
with the flow is that suggested by Kolmogorov. The eddy size is approximately
the depth of the convection zone, and this dissipation length corresponds to
the "mixing length". New terms involving local heating by turbulent dissipation
should appear in the stellar evolution equations. The enthalpy flux
("convective luminosity") is directly connected to the buoyant acceleration,
and hence the velocity scale. MLT tends to systematically underestimate this
velocity scale. Quantitative comparison with a variety of 3D simulations
reveals a previously recognized consistency. Examples of application to stellar
evolution will be presented in subsequent papers in this series.Comment: 47 pages, 7 figures, accepted by Ap
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