1,393 research outputs found
Calculation of three-dimensional compressible laminar and turbulent boundary flows. Three-dimensional compressible boundary layers of reacting gases over realistic configurations
A three-dimensional boundary-layer code was developed for particular application to realistic hypersonic aircraft. It is very general and can be applied to a wide variety of boundary-layer flows. Laminar, transitional, and fully turbulent flows of compressible, reacting gases are efficiently calculated by use of the code. A body-oriented orthogonal coordinate system is used for the calculation and the user has complete freedom in specifying the coordinate system within the restrictions that one coordinate must be normal to the surface and the three coordinates must be mutually orthogonal
An exploration of young people’s narratives of hope following experience of psychosis
Aims: To expand understandings of how young people with psychosis experience hope. This included to which factors young people attributed changes in their hopefulness and the role played by professionals and others with lived experience.
Method: Ten young people recovering from an experience of psychosis were interviewed using narrative methodology.
Results: The experience of hope as an overarching strand throughout the narratives had three common elements: sense of belonging, which included social inclusion, the importance of information and the significance
of planning and occupation. Professionals played an important role in facilitating small steps forwards.
Conclusions: The findings suggest the importance to young people of a sense of belonging and achieving small goals to facilitate hopeful thinking and, for clinicians, the value of supporting new peer relationships and
meaningful occupation
Modeling the interactions of phthalocyanines in water: From the Cu(II)-tetrasulphonate to the metal-free phthalocyanine
A quantum and statistical study on the effects of the ions Cu2+ and SO3− in the solvent structure around the metal-free phthalocyanine (H2Pc) is presented. We developed an ab initio interaction potential for the system CuPc–H2O based on quantum chemical calculations and studied its
transferability to the H2Pc–H2O and [CuPc(SO3)4]4−–H2O interactions. The use of the molecular dynamics technique allows the determination of energetic and structural properties of CuPc, H2Pc, and [CuPc(SO3)4]4− in water and the understanding of the keys for the different behaviors of the three phthalocyanine (Pc) derivatives in water. The inclusion of the Cu2+ cation in the Pc structure reinforces the appearance of two axial water molecules and second-shell water molecules in the solvent structure, whereas the presence of SO3− anions implies a well defined hydration shell
of about eight water molecules around them making the macrocycle soluble in water. Debye– Waller factors for axial water molecules have been obtained in order to examine the potential sensitivity of the extended x-ray absorption fine structure technique to detect the axial water molecules.Ministerio de Ciencia e Innovación de España-CTQ2008-0527
Theoretical study on the hydrophobic and hydrophilic hydration on large solutes: The case of phthalocyanines in water
A theoretical study on the hydration phenomena of three representative Phthalocyanines (Pcs): the metal-free, H2Pc, and the metal-containing, Cu-phthalocyanine, CuPc, and its soluble sulphonated derivative, [CuPc(SO3)4]4−, is presented. Structural and dynamic properties of molecular dynamics trajectories of these Pcs in solution were evaluated. The hydration shells of the Pcs were defined by means of spheroids adapted to the solute shape. Structural analysis of the axial region compared to the peripheral region indicates that there are no significant changes among the different macrocycles, but that of [CuPc(SO3)4]4−, where the polyoxoanion presence induces a typically hydrophilic hydration structure. The analyzed water dynamic properties cover mean residence times, translational and
orientational diffusion coefficients, and hydrogen bond network. These properties allow a thorough discussion about the simultaneous existence of hydrophobic and hydrophilic hydration in these macrocycles, and indicate the trend of water structure to well define shells in the environment of hydrophobic solutes. The comparison between the structural and dynamical analysis of the hydration of the amphipathic [CuPc(SO3)4]4− and the non-soluble Cu–Pc shows a very weak coupling among the hydrophilic and hydrophobic fragments of the macrocycle. Quantitative results are employed to revisit the iceberg model proposed by Frank and Evans, leading to conclude that structure and dy- namics support a non-strict interpretation of the iceberg view, although the qualitative trends pointed out by the model are supported.Junta de Andalucía P11-FQM7607Ministerio de Ciencia e Innovación CTQ2008-0527
Predictors of severe asthma attack re-attendance in Ecuadorian children: a cohort study.
Asthma is a common cause of emergency care attendance in low- and middle-income countries (LMICs). While few prospective studies of predictors for emergency care attendance have been undertaken in high-income countries, none have been performed in a LMIC.We followed a cohort of 5-15-year-old children treated for asthma attacks in emergency rooms of public health facilities in Esmeraldas City, Ecuador. We collected blood and nasal wash samples, and performed spirometry and exhaled nitric oxide fraction measurements. We explored potential predictors for recurrence of severe asthma attacks requiring emergency care over 6 months' follow-up.We recruited 283 children of whom 264 (93%) were followed-up for ≥6 months or until their next asthma attack. Almost half (46%) had a subsequent severe asthma attack requiring emergency care. Predictors of recurrence in adjusted analyses were (adjusted OR, 95% CI) younger age (0.87, 0.79-0.96 per year), previous asthma diagnosis (2.2, 1.2-3.9), number of parenteral corticosteroid courses in previous year (1.3, 1.1-1.5), food triggers (2.0, 1.1-3.6) and eczema diagnosis (4.2, 1.02-17.6). A parsimonious Cox regression model included the first three predictors plus urban residence as a protective factor (adjusted hazard ratio 0.69, 95% CI 0.50-0.95). Laboratory and lung function tests did not predict recurrence.Factors independently associated with recurrent emergency attendance for asthma attacks were identified in a low-resource LMIC setting. This study suggests that a simple risk-assessment tool could potentially be created for emergency rooms in similar settings to identify higher-risk children on whom limited resources might be better focused
The galaxy-halo connection from a joint lensing, clustering and abundance analysis in the CFHTLenS/VIPERS field
We present new constraints on the relationship between galaxies and their
host dark matter halos, measured from the location of the peak of the
stellar-to-halo mass ratio (SHMR), up to the most massive galaxy clusters at
redshift and over a volume of nearly 0.1~Gpc. We use a unique
combination of deep observations in the CFHTLenS/VIPERS field from the near-UV
to the near-IR, supplemented by secure spectroscopic redshifts,
analysing galaxy clustering, galaxy-galaxy lensing and the stellar mass
function. We interpret our measurements within the halo occupation distribution
(HOD) framework, separating the contributions from central and satellite
galaxies. We find that the SHMR for the central galaxies peaks at with an amplitude of ,
which decreases to for massive halos (). Compared to central galaxies only, the total SHMR (including
satellites) is boosted by a factor 10 in the high-mass regime (cluster-size
halos), a result consistent with cluster analyses from the literature based on
fully independent methods. After properly accounting for differences in
modelling, we have compared our results with a large number of results from the
literature up to : we find good general agreement, independently of the
method used, within the typical stellar-mass systematic errors at low to
intermediate mass () and the statistical
errors above. We have also compared our SHMR results to semi-analytic
simulations and found that the SHMR is tilted compared to our measurements in
such a way that they over- (under-) predict star formation efficiency in
central (satellite) galaxies.Comment: 31 pages, 18 figures, 4 table. Accepted for publication in MNRAS.
Online material available at http://www.cfhtlens.or
Liver stiffness and virologic outcomes after introducing tenofovir as part of antiretroviral therapy in lamivudine-experienced adults with HIV and hepatitis B virus (HBV) co-infection in Ghana: four-year follow up of the prospective HEPIK cohort
Introduction Until recently lamivudine was the only available agent to treat hepatitis B in the context of HIV infection in sub‐Saharan Africa. Tenofovir is gradually becoming available although access remains far from universal. Long‐term outcomes of introducing tenofovir as part of antiretroviral therapy (ART) in subjects previously extensively exposed to lamivudine as the sole HBV‐active agent in the region are unknown. Methods We report from a prospective cohort of HIV/HBV co‐infected adults attending for HIV care in Kumasi, Ghana, where HBsAg prevalence is 14%. HBsAg‐positive subjects were invited to attend for transient elastography (TE) and blood sampling before the introduction of tenofovir (TO) as part of ART, and within 1 year (T1) and 4 years (T2) of starting tenofovir. Adherence and alcohol consumption were determined by a questionnaire‐based interview. Results Overall 178 patients underwent evaluation at T0/T1, of whom 98 (55%) also attended for assessment at T2. Remaining patients were lost to follow up (50; 28%); had died (10; 6%); declined to attend (17; 10%); or were excluded due to pregnancy (2; 1 %) or invalid TE (1; 1 %). Of the 98 subjects, 94 had started tenofovir‐based ART and had received tenofovir for median 4 years (IQR 3.8, 4.1), while continuing previous lamivudine (Table 1). By multivariable linear regression, female gender, no history of alcohol excess, and higher HBV DNA level, higher liver stiffness, and lower platelet count at T0/T1 were significant predictors of decreasing liver stiffness between TO/1 and T2. No treatment‐emergent resistance mutations in HBV polymerase were observed by Sanger sequencing among subjects with HBV DNA>100 lU/ml at T2; one subject showed M204V+V173L+L180M at both TO and T2. Conclusions This is the first report of the long‐term impact on liver stiffness and virologic parameters of introducing tenofovir as part of ART in extensively lamivudine exposed HIV/HBV co‐infected patients in sub‐Saharan Africa. Significant reductions in liver stiffness and improved HBV control were observed at four years
Please mind the gap: students’ perspectives of the transition in academic skills between A-level and degree level geography
This paper explores first-year undergraduates’ perceptions of the transition from studying geography at pre-university level to studying for a degree. This move is the largest step students make in their education, and the debate about it in the UK has been reignited due to the government’s planned changes to A-level geography. However, missing from most of this debate is an appreciation of the way in which geography students themselves perceive their transition to university. This paper begins to rectify this absence. Using student insights, we show that their main concern is acquiring the higher level skills required for university learning
Education policy as an act of white supremacy: whiteness, critical race theory and education reform
The paper presents an empirical analysis of education policy in England that is informed by recent developments in US critical theory. In particular, I draw on ‘whiteness studies’ and the application of Critical Race Theory (CRT). These perspectives offer a new and radical way of conceptualising the role of racism in education. Although the US literature has paid little or no regard to issues outside North America, I argue that a similar understanding of racism (as a multifaceted, deeply embedded, often taken-for-granted aspect of power relations) lies at the heart of recent attempts to understand institutional racism in the UK. Having set out the conceptual terrain in the first half of the paper, I then apply this approach to recent changes in the English education system to reveal the central role accorded the defence (and extension) of race inequity. Finally, the paper touches on the question of racism and intentionality: although race inequity may not be a planned and deliberate goal of education policy neither is it accidental. The patterning of racial advantage and inequity is structured in domination and its continuation represents a form of tacit intentionality on the part of white powerholders and policy makers. It is in this sense that education policy is an act of white supremacy. Following others in the CRT tradition, therefore, the paper’s analysis concludes that the most dangerous form of ‘white supremacy’ is not the obvious and extreme fascistic posturing of small neonazi groups, but rather the taken-for-granted routine privileging of white interests that goes unremarked in the political mainstream
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