Search results

Filter

Filetype

Your search for "*" yielded 529437 hits

Decreased Kidney Function of Unknown Cause in Nicaragua: A Community-Based Survey

Background: End-stage kidney disease overwhelms health services in Central America. We determined prevalences of decreased kidney function in distinct populations in the most affected region of Nicaragua. Study Design: Cross-sectional survey. Setting & Participants: Total populations aged 20-60 years of 5 villages in Northwest Nicaragua: mining/subsistence farming (elevation, 100-300 m above s

High resolution multiphoton spectroscopy by a tunable free-electron-laser light.

Seeded free electron lasers theoretically have the intensity, tunability, and resolution required for multiphoton spectroscopy of atomic and molecular species. Using the seeded free electron laser FERMI and a novel detection scheme, we have revealed the two-photon excitation spectra of dipole-forbidden doubly excited states in helium. The spectral profiles of the lowest (-1,0)^{+1} ^{1}S^{e} and (

Shifts in plant respiration and carbon use efficiency at a large-scale drought experiment in the eastern Amazon

P>The effects of drought on the Amazon rainforest are potentially large but remain poorly understood. Here, carbon (C) cycling after 5 yr of a large-scale through-fall exclusion (TFE) experiment excluding about 50% of incident rainfall from an eastern Amazon rainforest was compared with a nearby control plot. Principal C stocks and fluxes were intensively measured in 2005. Additional minor compone

A risk score for predicting 30-day mortality in heart failure patients undergoing non-cardiac surgery

BackgroundHeart failure is an established risk factor for poor outcomes in patients undergoing non-cardiac surgery, yet risk stratification remains a clinical challenge. We developed an index for 30-day mortality risk prediction in this particular group. Methods and resultsAll individuals with heart failure undergoing non-cardiac surgery between October 23 2004 and October 31 2011 were included fr

On transfer operators and maps with random holes

We study Markov interval maps with random holes. The holes are not necessarily elements of the Markov partition. Under a suitable, and physically relevant, assumption on the noise, we show that the transfer operator associated with the random open system can be reduced to a transfer operator associated with the closed deterministic system. Exploiting this fact, we show that the random open system

Ultrastructural Heterogeneity of Carbonaceous Material in Ancient Cherts: Investigating Biosignature Origin and Preservation.

Opaline silica deposits on Mars may be good target sites where organic biosignatures could be preserved. Potential analogues on Earth are provided by ancient cherts containing carbonaceous material (CM) permineralized by silica. In this study, we investigated the ultrastructure and chemical characteristics of CM in the Rhynie chert (c. 410 Ma, UK), Bitter Springs Formation (c. 820 Ma, Australia),

Effect of Supercritical Carbon Dioxide on the Thermodynamics of Model Blends of Styrene-Acrylonitrile Copolymer and Poly(methyl methacrylate) Studied by Small-Angle Neutron Scattering

Quantitative analysis of small angle neutron scattering (SANS) data from homogeneous multicomponent mixtures of supercritical carbon dioxide (scCO(2)) and two polymers is presented for the first time. The two polymers used in this study were styrene-acrylonitrile copolymer (SAN) and deuterated poly(methyl methacrylate) (dPMMA). Model polymers were used to facilitate comparisons between theory and

Biomechanical properties of bone in a mouse model of Rett syndrome.

Rett syndrome (RTT) is an X-linked genetic disorder and a major cause of intellectual disability in girls. Mutations in the methyl-CpG binding protein 2 (MECP2) gene are the primary cause of the disorder. Despite the dominant neurological phenotypes, MECP2 is expressed ubiquitously throughout the body and a number of peripheral phenotypes such as scoliosis, reduced bone mineral density and skeleta

Experimental evidence for foraminiferal calcification under anoxia

Benthic foraminiferal tests are widely used for paleoceanographic reconstructions from a range of different environments with varying dissolved oxygen concentrations in the bottom water. There is ample evidence that foraminifera can live in anoxic sediments. For some species, this is explained by a switch to facultative anaerobic metabolism (i.e. denitrification). Here we show for the first time t

Rho Kinase-related Proteins in Human Vaginal Arteries: An Immunohistochemical and Functional Study

The calcium-sensitizing Rho A/Rho kinase pathway has been suggested to play a role in the control of nongenital vascular smooth muscle. Rho-associated kinases (ROKs) cause calcium-independent modulation of smooth muscle contraction, and have been demonstrated in the bladder, prostate, and corpus cavernosum. Until now, it is not known whether ROKs and related proteins play a role in the control of

HLA-DPB1*04:01 Protects Genetically Susceptible Children from Celiac Disease Autoimmunity in the TEDDY Study.

Tissue transglutaminase autoantibodies (tTGAs) represent the first evidence of celiac disease (CD) development. Associations of HLA-DR3-DQA1*05:01-DQB1*02:01 (i.e., DR3-DQ2) and, to a lesser extent, DR4-DQA1*03:01-DQB1*03:02 (i.e., DR4-DQ8) with the risk of CD differ by country, consistent with additional genetic heterogeneity that further refines risk. Therefore, we examined human leukocyte antig

Mature biofilms of Enterococcus faecalis and Enterococcus faecium are highly resistant to antibiotics.

Enterococcus faecalis and Enterococcus faecium are important nosocomial pathogens that form biofilms on implanted materials. We compare the antibiotic sensitivity of bacteria in new (established during 24hours) and mature (established during 120hours) enterococcal biofilms. Mature biofilms contained more bacteria and were much more tolerant to antibiotics, including rifampicin-containing combinati

Daily Variability in Working Memory is Coupled With Negative Affect: The Role of Attention and Motivation

Across days, individuals experience varying levels of negative affect, control of attention, and motivation. We investigated whether this intraindividual variability was coupled with daily fluctuations in working memory (WM) performance. In 100 days, 101 younger individuals worked on a spatial N-back task and rated negative affect, control of attention, and motivation. Results showed that individu

Wildfires in boreal ecoregions: Evaluating the power law assumption and intra-annual and interannual variations

Wildfires are a major driver of ecosystem development and contributor to carbon emissions in boreal forests. We analyzed the contribution of fires of different fire size classes to the total burned area and suggest a novel fire characteristic, the characteristic fire size, i.e., the fire size class with the highest contribution to the burned area, its relation to bioclimatic conditions, and intra-

Evolution and stability of the G-matrix during the colonization of a novel environment.

Populations that undergo a process of rapid evolution present excellent opportunities to investigate the mechanisms driving or restraining adaptive divergence. The genetic variance-covariance matrix (G) is often considered to constrain adaptation but little is known about its potential to evolve during phenotypic divergence. We compared the G-matrices of ancestral and recently established ecotype

How are hydrogen bonds modified by metal binding?

We have used density functional theory calculations to investigate how the hydrogen-bond strength is modified when a ligand is bound to a metal using over 60 model systems involving six metals and eight ligands frequently encountered in metalloproteins. We study how the hydrogen-bond geometry and energy vary with the nature of metal, the oxidation state, the coordination number, the ligand involve

The phylogenomics of protein structures: The backstory.

In this introductory retrospective, evolution as viewed through gene trees is inspected through a lens compounded from its founding operational assumptions. The four assumptions of the gene tree culture that are singularly important to evolutionary interpretations are: a. that protein-coding sequences are molecular fossils; b. that gene trees are equivalent to species trees; c. that the tree of li