166 research outputs found
CaracterĂsticas morfolĂłgicas e fitossanitĂĄrias de variedades de roseira na etapa de classificação
Theory of Coexistence of Superconductivity and Ferroelectricity : A Dynamical Symmetry Model
We propose and investigate a model for the coexistence of Superconductivity
(SC) and Ferroelectricity (FE) based on the dynamical symmetries for
the pseudo-spin SC sector, for the displaced oscillator FE sector, and
for the composite system. We assume a minimal
symmetry-allowed coupling, and simplify the hamiltonian using a double mean
field approximation (DMFA). A variational coherent state (VCS) trial
wave-function is used for the ground state: the energy, and the relevant order
parameters for SC and FE are obtained. For positive sign of the SC-FE coupling
coefficient, a non-zero value of either order parameter can suppress the other
(FE polarization suppresses SC and vice versa). This gives some support to
"Matthias' Conjecture" [1964], that SC and FE tend to be mutually exclusive.
For such a Ferroelectric Superconductor we predict: a) the SC gap
(and ) will increase with increasing applied pressure when pressure
quenches FE as in many ferroelectrics, and b) the FE polarization will increase
with increaesing magnetic field up to . The last result is equivalent to
the prediction of a new type of Magneto-Electric Effect in a coexistent SC-FE
material. Some discussion will be given of the relation of these results to the
cuprate superconductors.Comment: 46 page
Risk Factors for Perioperative Brain Lesions in Infants With Congenital Heart Disease:A European Collaboration
Infants with congenital heart disease are at risk of brain injury and impaired neurodevelopment. The aim was to investigate risk factors for perioperative brain lesions in infants with congenital heart disease. METHODS: Infants with transposition of the great arteries, single ventricle physiology, and left ventricular outflow tract and/or aortic arch obstruction undergoing cardiac surgery <6 weeks after birth from 3 European cohorts (Utrecht, Zurich, and London) were combined. Brain lesions were scored on preoperative (transposition of the great arteries N=104; single ventricle physiology N=35; and left ventricular outflow tract and/or aortic arch obstruction N=41) and postoperative (transposition of the great arteries N=88; single ventricle physiology N=28; and left ventricular outflow tract and/or aortic arch obstruction N=30) magnetic resonance imaging for risk factor analysis of arterial ischemic stroke, cerebral sinus venous thrombosis, and white matter injury. RESULTS: Preoperatively, induced vaginal delivery (odds ratio [OR], 2.23 [95% CI, 1.06â4.70]) was associated with white matter injury and balloon atrial septostomy increased the risk of white matter injury (OR, 2.51 [95% CI, 1.23â5.20]) and arterial ischemic stroke (OR, 4.49 [95% CI, 1.20â21.49]). Postoperatively, younger postnatal age at surgery (OR, 1.18 [95% CI, 1.05â1.33]) and selective cerebral perfusion, particularly at â€20â°C (OR, 13.46 [95% CI, 3.58â67.10]), were associated with new arterial ischemic stroke. Single ventricle physiology was associated with new white matter injury (OR, 2.88 [95% CI, 1.20â6.95]) and transposition of the great arteries with new cerebral sinus venous thrombosis (OR, 13.47 [95% CI, 2.28â95.66]). Delayed sternal closure (OR, 3.47 [95% CI, 1.08â13.06]) and lower intraoperative temperatures (OR, 1.22 [95% CI, 1.07â1.36]) also increased the risk of new cerebral sinus venous thrombosis. CONCLUSIONS: Delivery planning and surgery timing may be modifiable risk factors that allow personalized treatment to minimize the risk of perioperative brain injury in severe congenital heart disease. Further research is needed to optimize cerebral perfusion techniques for neonatal surgery and to confirm the relationship between cerebral sinus venous thrombosis and perioperative risk factors
A new strategy for enhancing imputation quality of rare variants from next-generation sequencing data via combining SNP and exome chip data
Background: Rare variants have gathered increasing attention as a possible alternative source of missing heritability. Since next generation sequencing technology is not yet cost-effective for large-scale genomic studies, a widely used alternative approach is imputation. However, the imputation approach may be limited by the low accuracy of the imputed rare variants. To improve imputation accuracy of rare variants, various approaches have been suggested, including increasing the sample size of the reference panel, using sequencing data from study-specific samples (i.e., specific populations), and using local reference panels by genotyping or sequencing a subset of study samples. While these approaches mainly utilize reference panels, imputation accuracy of rare variants can also be increased by using exome chips containing rare variants. The exome chip contains 250 K rare variants selected from the discovered variants of about 12,000 sequenced samples. If exome chip data are available for previously genotyped samples, the combined approach using a genotype panel of merged data, including exome chips and SNP chips, should increase the imputation accuracy of rare variants. Results: In this study, we describe a combined imputation which uses both exome chip and SNP chip data simultaneously as a genotype panel. The effectiveness and performance of the combined approach was demonstrated using a reference panel of 848 samples constructed using exome sequencing data from the T2D-GENES consortium and 5,349 sample genotype panels consisting of an exome chip and SNP chip. As a result, the combined approach increased imputation quality up to 11 %, and genomic coverage for rare variants up to 117.7 % (MAF < 1 %), compared to imputation using the SNP chip alone. Also, we investigated the systematic effect of reference panels on imputation quality using five reference panels and three genotype panels. The best performing approach was the combination of the study specific reference panel and the genotype panel of combined data. Conclusions: Our study demonstrates that combined datasets, including SNP chips and exome chips, enhances both the imputation quality and genomic coverage of rare variants
Definition, aims, and implementation of GA2LEN/HAEi Angioedema Centers of Reference and Excellence
Planck early results. XX. New light on anomalous microwave emission from spinning dust grains
Anomalous microwave emission (AME) has been observed by numerous experiments in the frequency range âŒ10â60 GHz. Using Planck maps
and multi-frequency ancillary data, we have constructed spectra for two known AME regions: the Perseus and Ï Ophiuchi molecular clouds. The
spectra are well fitted by a combination of free-free radiation, cosmic microwave background, thermal dust, and electric dipole radiation from
small spinning dust grains. The spinning dust spectra are the most precisely measured to date, and show the high frequency side clearly for the
first time. The spectra have a peak in the range 20â40 GHz and are detected at high significances of 17.1Ï for Perseus and 8.4Ï for Ï Ophiuchi.
In Perseus, spinning dust in the dense molecular gas can account for most of the AME; the low density atomic gas appears to play a minor role.
In Ï Ophiuchi, the âŒ30 GHz peak is dominated by dense molecular gas, but there is an indication of an extended tail at frequencies 50â100 GHz,
which can be accounted for by irradiated low density atomic gas. The dust parameters are consistent with those derived from other measurements.
We have also searched the Planck map at 28.5 GHz for candidate AME regions, by subtracting a simple model of the synchrotron, free-free, and
thermal dust. We present spectra for two of the candidates; S140 and S235 are bright Hii regions that show evidence for AME, and are well fitted
by spinning dust models
TRY plant trait database â enhanced coverage and open access
Plant traitsâthe morphological, anatomical, physiological, biochemical and phenological characteristics of plantsâdetermine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of traitâbased plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traitsâalmost complete coverage for âplant growth formâ. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and traitâenvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Evaluating the contribution of rare variants to type 2 diabetes and related traits using pedigrees
A major challenge in evaluating the contribution of rare variants to complex disease is identifying enough copies of the rare alleles to permit informative statistical analysis. To investigate the contribution of rare variants to the risk of type 2 diabetes (T2D) and related traits, we performed deep whole-genome analysis of 1,034 members of 20 large Mexican-American families with high prevalence of T2D. If rare variants of large effect accounted for much of the diabetes risk in these families, our experiment was powered to detect association. Using gene expression data on 21,677 transcripts for 643 pedigree members, we identified evidence for large-effect rare-variant cis-expression quantitative trait loci that could not be detected in population studies, validating our approach. However, we did not identify any rare variants of large effect associated with T2D, or the related traits of fasting glucose and insulin, suggesting that large-effect rare variants account for only a modest fraction of the genetic risk of these traits in this sample of families. Reliable identification of large-effect rare variants will require larger samples of extended pedigrees or different study designs that further enrich for such variants
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