Vitamin D and Risk of Neuroimaging Abnormalities.

Vitamin D deficiency has been linked with an increased risk of incident all-cause dementia and Alzheimer's disease. The aim of the current study was to explore the potential mechanisms underlying these associations by determining whether low vitamin D concentrations are associated with the development of incident cerebrovascular and neurodegenerative neuroimaging abnormalities. The population consisted of 1,658 participants aged ≥65 years from the US-based Cardiovascular Health Study who were free from prevalent cardiovascular disease, stroke and dementia at baseline in 1992-93. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were determined by liquid chromatography-tandem mass spectrometry from blood samples collected at baseline. The first MRI scan was conducted between 1991-1994 and the second MRI scan was conducted between 1997-1999. Change in white matter grade, ventricular grade and presence of infarcts between MRI scan one and two were used to define neuroimaging abnormalities. During a mean follow-up of 5.0 years, serum 25(OH)D status was not significantly associated with the development of any neuroimaging abnormalities. Using logistic regression models, the multivariate adjusted odds ratios (95% confidence interval) for worsening white matter grade in participants who were severely 25(OH)D deficient (<25 nmol/L) and deficient (≥25-50 nmol/L) were 0.76 (0.35-1.66) and 1.09 (0.76-1.55) compared to participants with sufficient concentrations (≥50 nmol/L). The multivariate adjusted odds ratios for ventricular grade in participants who were severely 25(OH)D deficient and deficient were 0.49 (0.20-1.19) and 1.12 (0.79-1.59) compared to those sufficient. The multivariate adjusted odds ratios for incident infarcts in participants who were severely 25(OH)D deficient and deficient were 1.95 (0.84-4.54) and 0.73 (0.47-1.95) compared to those sufficient. Overall, serum vitamin D concentrations could not be shown to be associated with the development of cerebrovascular or neurodegenerative neuroimaging abnormalities in Cardiovascular Health Study participants.The Cardiovascular Health Study was supported by contracts HHSN268201200036C, HHSN268200800007C, N01 HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086, and grant HL080295 from the National Heart, Lung, and Blood Institute (NHLBI), with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS). Additional support was provided by AG023629, AG20098, AG15928 and HL084443 from the National Institute on Aging (NIA). A full list of principal CHS investigators and institutions can be found at chs-nhlbi.org. Additional support was also provided by NIRG-11-200737 from the Alzheimer’s Association, the Mary Kinross Charitable Trust, the James Tudor Foundation, the Halpin Trust, the Age Related Diseases and Health Trust, and the Norman Family Charitable Trust (to D.J.L.). This research was supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care South West Peninsula at the Royal Devon and Exeter NHS Foundation Trust. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The National Institutes of Health was involved in the original design and conduct of the Cardiovascular Health Study and in the data collection methods

A simple drain current model for Schottky-barrier carbon nanotube field effect transistors

We report on a new computational model to efficiently simulate carbon nanotubebased field effect transistors (CNT-FET). In the model, a central region is formed by a semiconducting nanotube that acts as the conducting channel, surrounded by a thin oxide layer and a metal gate electrode. At both ends of the semiconducting channel, two semi-infinite metallic reservoirs act as source and drain contacts. The current-voltage characteristics are computed using the Landauer formalism, including the effect of the Schottky barrier physics. The main operational regimes of the CNT-FET are described, including thermionic and tunnel current components, capturing ambipolar conduction, multichannel ballistic transport and electrostatics dominated by the nanotube capacitance. The calculations are successfully compared to results given by more sophisticated methods based on non-equilibrium Green's function formalism (NEGF).Comment: 22 pages, 9 figure

Gravitational stability and dynamical overheating of stellar disks of galaxies

We use the marginal stability condition for galactic disks and the stellar velocity dispersion data published by different authors to place upper limits on the disk local surface density at two radial scalelengths $R=2h$. Extrapolating these estimates, we constrain the total mass of the disks and compare these estimates to those based on the photometry and color of stellar populations. The comparison reveals that the stellar disks of most of spiral galaxies in our sample cannot be substantially overheated and are therefore unlikely to have experienced a significant merging event in their history. The same conclusion applies to some, but not all of the S0 galaxies we consider. However, a substantial part of the early type galaxies do show the stellar velocity dispersion well in excess of the gravitational stability threshold suggesting a major merger event in the past. We find dynamically overheated disks among both seemingly isolated galaxies and those forming pairs. The ratio of the marginal stability disk mass estimate to the total galaxy mass within four radial scalelengths remains within a range of 0.4---0.8. We see no evidence for a noticeable running of this ratio with either the morphological type or color index.Comment: 25 pages, 5 figures, accepted to Astronomy Letter

Synergy of extreme drought and shrub invasion reduce ecosystem functioning and resilience in water-limited climates

Extreme drought events and plant invasions are major drivers of global change that can critically affect ecosystem functioning and alter ecosystem-atmosphere exchange. Invaders are expanding worldwide and extreme drought events are projected to increase in frequency and intensity. However, very little is known on how these drivers may interact to affect the functioning and resilience of ecosystems to extreme events. Using a manipulative shrub removal experiment and the co-occurrence of an extreme drought event (2011/2012) in a Mediterranean woodland, we show that native shrub invasion and extreme drought synergistically reduced ecosystem transpiration and the resilience of key-stone oak tree species. Ecosystem transpiration was dominated by the water use of the invasive shrub Cistus ladanifer, which further increased after the extreme drought event. Meanwhile, the transpiration of key-stone tree species decreased, indicating a competitive advantage in favour of the invader. Our results suggest that in Mediterranean-type climates the invasion of water spending species and projected recurrent extreme drought events may synergistically cause critical drought tolerance thresholds of key-stone tree species to be surpassed, corroborating observed higher tree mortality in the invaded ecosystems. Ultimately, this may shift seasonally water limited ecosystems into less desirable alternative states dominated by water spending invasive shrubs

Burden of anemia in patients with osteoarthritis and rheumatoid arthritis in French secondary care

<p>Abstract</p> <p>Background</p> <p>Arthritic disorders can be the cause of hospitalizations, especially among individuals 60 years and older. The objective of this study is to investigate associations between health care resource utilization in arthritis patients with and without concomitant anemia in a secondary care setting in France.</p> <p>Methods</p> <p>This retrospective cohort study utilized data on secondary care activity in 2001 from the Programme de Médicalisation des Systèmes d'Information database. Two cohorts were defined using ICD-10 codes: patients with an arthritis diagnosis with a concomitant diagnosis of anemia; and arthritis patients without anemia. Health care resource utilization for both populations was analyzed separately in public and private hospitals. Study outcomes were compared between the cohorts using standard bivariate and multivariable methods.</p> <p>Results</p> <p>There were 300,865 hospitalizations for patients with arthritis only, and 2,744 for those with concomitant anemia. Over 70% of patients with concomitant anemia were in public hospitals, compared with 53.5% of arthritis-only patients. Arthritis patients without anemia were younger than those with concomitant anemia (mean age 66.7 vs 74.6, public hospitals; 67.1 vs 72.2, private hospitals). Patients with concomitant anemia/arthritis only had a mean length of stay of 11.91 (SD 14.07)/8.04 (SD 9.93) days in public hospitals, and 10.68 (SD 10.16)/9.83 (SD 7.76) days in private hospitals. After adjusting for confounders, the mean (95% CI) additional length of stay for arthritis patients with concomitant anemia, compared with those with arthritis only, was 1.56 (1.14-1.98) days in public and 0.69 (0.22-1.16) days in private hospitals. Costs per hospitalization were €;480 (227-734) greater for arthritis patients with anemia in public hospitals, and €;30 (-113-52) less in private hospitals, than for arthritis-only patients.</p> <p>Conclusions</p> <p>Arthritis patients with concomitant anemia have a longer length of stay, undergo more procedures, and have higher hospitalization costs than nonanemic arthritis patients in public hospitals in France. In private hospitals, concomitant anemia was associated with modest increases in length of stay and number of procedures; however, this did not translate into higher costs. Such evidence of anemia-related health care utilization and costs can be considered as a proxy for the clinical significance of anemia.</p

Predicting clinically unrecognized coronary artery disease: use of two- dimensional echocardiography

<p>Abstract</p> <p>Background</p> <p>2-D Echo is often performed in patients without history of coronary artery disease (CAD). We sought to determine echo features predictive of CAD.</p> <p>Methods</p> <p>2-D Echo of 328 patients without known CAD performed within one year prior to stress myocardial SPECT and angiography were reviewed. Echo features examined were left ventricular and atrial enlargement, LV hypertrophy, wall motion abnormality (WMA), LV ejection fraction (EF) < 50%, mitral annular calcification (MAC) and aortic sclerosis/stenosis (AS). High risk myocardial perfusion abnormality (MPA) was defined as >15% LV perfusion defect or multivessel distribution. Severe coronary artery stenosis (CAS) was defined as left main, 3 VD or 2VD involving proximal LAD.</p> <p>Results</p> <p>The mean age was 62 ± 13 years, 59% men, 29% diabetic (DM) and 148 (45%) had > 2 risk factors. Pharmacologic stress was performed in 109 patients (33%). MPA was present in 200 pts (60%) of which, 137 were high risk. CAS was present in 166 pts (51%), 75 were severe. Of 87 patients with WMA, 83% had MPA and 78% had CAS. Multivariate analysis identified age >65, male, inability to exercise, DM, WMA, MAC and AS as independent predictors of MPA and CAS. Independent predictors of high risk MPA and severe CAS were age, DM, inability to exercise and WMA.</p> <p>2-D echo findings offered incremental value over clinical information in predicting CAD by angiography. (Chi square: 360 vs. 320 p = 0.02).</p> <p>Conclusion</p> <p>2-D Echo was valuable in predicting presence of physiological and anatomical CAD in addition to clinical information.</p

Homeschooling and the criticism of school: hybridisms and educational (dis)continuities

Desde os anos 1960, o homeschooling apresenta dinâmicas de crescimento atualizadas nos diagnósticos da crise do capitalismo e dos sistemas educativos. Por ser praticado por famílias próximas do progressismo libertário, do cristianismo conservador ou de outras inspirações axiológicas, a abordagem investigativa presente neste texto pressupôs romper com uma visão unívoca e alheia à sua diversidade e aos diferentes graus de (in)formalidade dos quotidianos educativos de crianças e de jovens que caracterizam este fenómeno educativo. Procura-se captar as especificidades do ensino doméstico (ED) em Portugal e a sua crescente expressão social e educacional e reflete-se sobre os sentidos das aprendizagens que ele encerra. Conclui-se que o ED parece ser contrário aos horizontes formativos da criança segundo o interesse da sociedade, sendo omisso sobre o seu papel na emancipação dos sujeitos. Confrontam-se a escola e o seu modo de funcionamento a partir do racional do ED, à procura de novas epistemologias e de novas linhas de pesquisa.Since the 1960s, homeschooling has shown growth dynamics updated by the diagnosis of the crisis of capitalism and of educational systems. Because it is practiced by families close to libertarian progressivism, conservative Christianity, or other axiological inspirations, this paper’s approach sought to break with a univocal conception alien to its diversity and to the different degrees of (in)formality of the children’s and young people’s educational daily lives inherent to this educational practice. Therefore, this paper seeks to understand the specificities of Portuguese homeschooling and its increasing social and educational expression, and to reflect on the meanings of the learning it entails. Being unclear about its role on the emancipation of the subjects, homeschooling seems to be contrary to the educational horizons of the child according to the interests of the whole society. This paper confronts school and its way of functioning with the homeschooling rationale in order to search for new epistemologies and new lines of research.info:eu-repo/semantics/publishedVersio

A prediction rule to stratify mortality risk of patients with pulmonary tuberculosis

Tuberculosis imposes high human and economic tolls, including in Europe. This study was conducted to develop a severity assessment tool for stratifying mortality risk in pulmonary tuberculosis (PTB) patients. A derivation cohort of 681 PTB cases was retrospectively reviewed to generate a model based on multiple logistic regression analysis of prognostic variables with 6-month mortality as the outcome measure. A clinical scoring system was developed and tested against a validation cohort of 103 patients. Five risk features were selected for the prediction model: hypoxemic respiratory failure (OR 4.7, 95% CI 2.8-7.9), age >= 50 years (OR 2.9, 95% CI 1.7-4.8), bilateral lung involvement (OR 2.5, 95% CI 1.44.4), >= 1 significant comorbidity-HIV infection, diabetes mellitus, liver failure or cirrhosis, congestive heart failure and chronic respiratory disease-(OR 2.3, 95% CI 1.3-3.8), and hemoglobin = 6) mortality risk. The mortality associated with each group was 2.9%, 22.9% and 53.9%, respectively. The model performed equally well in the validation cohort. We provide a new, easy-to-use clinical scoring system to identify PTB patients with high-mortality risk in settings with good healthcare access, helping clinicians to decide which patients are in need of closer medical care during treatment.This work was supported by Fundacao Amelia de Mello/Jose de Mello Saude and Sociedade Portuguesa de Pneumologia (SPP). This work was developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). NSO is a FCT (Fundacao para a Ciencia e Tecnologia) investigator. MS is an Associate FCT Investigator. The fundershad no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Using serological measures to monitor changes in malaria transmission in Vanuatu

BACKGROUND: With renewed interest in malaria elimination, island environments present unique opportunities to achieve this goal. However, as transmission decreases, monitoring and evaluation programmes need increasingly sensitive tools to assess Plasmodium falciparum and Plasmodium vivax exposure. In 2009, to assess the role of serological markers in evaluating malaria transmission, a cross-sectional seroprevalence study was carried out in Tanna and Aneityum, two of the southernmost islands of the Vanuatu archipelago, areas where malaria transmission has been variably reduced over the past few decades. METHODS: Malaria transmission was assessed using serological markers for exposure to P. falciparum and P. vivax. Filter blood spot papers were collected from 1,249 people from Tanna, and 517 people from Aneityum to assess the prevalence of antibodies to two P. falciparum antigens (MSP-119 and AMA-1) and two P. vivax antigens (MSP-119 and AMA-1). Age-specific prevalence was modelled using a simple catalytic conversion model based on maximum likelihood to generate a community seroconversion rate (SCR). RESULTS: Overall seropositivity in Tanna was 9.4%, 12.4% and 16.6% to P. falciparum MSP-119, AMA-1 and Schizont Extract respectively and 12.6% and 15.0% to P. vivax MSP-119 and AMA-1 respectively. Serological results distinguished between areas of differential dominance of either P. vivax or P. falciparum and analysis of age-stratified results showed a step in seroprevalence occurring approximately 30 years ago on both islands, indicative of a change in transmission intensity at this time. Results from Aneityum suggest that several children may have been exposed to malaria since the 2002 P. vivax epidemic. CONCLUSION: Seroepidemiology can provide key information on malaria transmission for control programmes, when parasite rates are low. As Vanuatu moves closer to malaria elimination, monitoring changes in transmission intensity and identification of residual malaria foci is paramount in order to concentrate intervention efforts

Genomic characterization of large rearrangements of the LDLR gene in Czech patients with familial hypercholesterolemia

<p>Abstract</p> <p>Background</p> <p>Mutations in the <it>LDLR </it>gene are the most frequent cause of Familial hypercholesterolemia, an autosomal dominant disease characterised by elevated concentrations of LDL in blood plasma. In many populations, large genomic rearrangements account for approximately 10% of mutations in the <it>LDLR </it>gene.</p> <p>Methods</p> <p>DNA diagnostics of large genomic rearrangements was based on Multiple Ligation dependent Probe Amplification (MLPA). Subsequent analyses of deletion and duplication breakpoints were performed using long-range PCR, PCR, and DNA sequencing.</p> <p>Results</p> <p>In set of 1441 unrelated FH patients, large genomic rearrangements were found in 37 probands. Eight different types of rearrangements were detected, from them 6 types were novel, not described so far. In all rearrangements, we characterized their exact extent and breakpoint sequences.</p> <p>Conclusions</p> <p>Sequence analysis of deletion and duplication breakpoints indicates that intrachromatid non-allelic homologous recombination (NAHR) between <it>Alu </it>elements is involved in 6 events, while a non-homologous end joining (NHEJ) is implicated in 2 rearrangements. Our study thus describes for the first time NHEJ as a mechanism involved in genomic rearrangements in the <it>LDLR </it>gene.</p