10,451 research outputs found
Distribution and Diversity of Archaeal and Bacterial Ammonia Oxidizers in Salt Marsh Sediments
Diversity and abundance of ammonia-oxidizing Betaproteobacteria (β-AOB) and archaea (AOA) were investigated in a New England salt marsh at sites dominated by short or tall Spartina alterniflora (SAS and SAT sites, respectively) or Spartina patens (SP site). AOA amoA gene richness was higher than β-AOB amoA richness at SAT and SP, but AOA and β-AOB richness were similar at SAS. β-AOB amoA clone libraries were composed exclusively of Nitrosospira-like amoA genes. AOA amoA genes at SAT and SP were equally distributed between the water column/sediment and soil/sediment clades, while AOA amoA sequences at SAS were primarily affiliated with the water column/sediment clade. At all three site types, AOA were always more abundant than β-AOB based on quantitative PCR of amoA genes. At some sites, we detected 109 AOA amoA gene copies g of sediment−1. Ratios of AOA to β-AOB varied over 2 orders of magnitude among sites and sampling dates. Nevertheless, abundances of AOA and β-AOB amoA genes were highly correlated. Abundance of 16S rRNA genes affiliated with Nitrosopumilus maritimus, Crenarchaeota group I.1b, and pSL12 were positively correlated with AOA amoA abundance, but ratios of amoA to 16S rRNA genes varied among sites. We also observed a significant effect of pH on AOA abundance and a significant salinity effect on both AOA and β-ΑΟΒ abundance. Our results expand the distribution of AOA to salt marshes, and the high numbers of AOA at some sites suggest that salt marsh sediments serve as an important habitat for AOA
NMR and LDA evidence for spiral magnetic order in the chain cuprate LiCu2O2
We report on {6,7}Li nuclear magnetic resonance measurements of the
spin-chain compound LiCu2O2 in the paramagnetic and magnetically ordered
states. Below T about 24 K the NMR lineshape presents a clear signature of
incommensurate (IC) static modulation of the local magnetic field consistent
with an IC spiral modulation of the magnetic moments. {7}Li NMR reveals strong
phason-like dynamical fluctuations extending well below 24 K. We hypothesize
that a series of phase transitions at 24.2, 22.5, and 9 K reflects a "Devil's
staircase" type behavior generic for IC systems. LDA based calculations of
exchange integrals reveal a large in-chain frustration leading to a magnetical
spiral.Comment: 4 pages, 4 figure
Computed tomography measures of nutrition in patients with end-stage liver disease provide a novel approach to characterize deficits
Aim
Patients with cirrhosis and end-stage liver disease (ESLD) develop severe nutrition deficits that impact on morbidity and mortality. Laboratory measures of nutrition fail to fully assess clinical deficits in muscle mass and fat stores. This study employs computed tomography imaging to assess muscle mass and subcutaneous and visceral fat stores in patients with ESLD.
Methods
This 1:1 case-control study design compares ESLD patients with healthy controls. Study patients were selected from a database of ESLD patients using a stratified method to assure a representative sample based on age, body mass index (BMI), gender, and model for end-stage liver disease score (MELD). Control patients were trauma patients with a low injury severity score (<10) who had a CT scan during evaluation. Cases and controls were matched for age +/- 5 years, gender, and BMI +/- 2.
Results
There were 90 subjects and 90 controls. ESLD patients had lower albumin levels (p<0.001), but similar total protein levels (p=0.72). ESLD patients had a deficit in muscle mass (-19%, p<0.001) and visceral fat (-13%, p<0.001), but similar subcutaneous fat (-1%, p=0.35). ESLD patients at highest risk for sarcopenia included those over age 60, BMI< 25.0, and female gender. We found degree of sarcopenia to be independent of MELD score.
Conclusions
These results support previous research demonstrating substantial nutrition deficits in ESLD patients that are not adequately measured by laboratory testing. Patients with ESLD have significant deficits of muscle and visceral fat stores, but a similar amount of subcutaneous fat
Dedication of the Palomar Observatory and the Hale Telescope
The dedication of the Palomar Observatory, if it were being held in England, would be accompanied by brilliant pageantry both of the state, with its knights, heralds, pursuivants, kings at arms, admirals and captains, and of the church with its bishops, priests and deacons, crucifiers and choirs; and I am sure that we feel the quality of religion in this ceremony. We would hear the choirs chanting in antiphony that great canticle which so delights the choir boys: Benedicite, omnia opera Domini
Magnetic phase diagram of the frustrated S=1/2 chain magnet LiCu_2O_2
We present the results of the magnetization and dielectric constant
measurements on untwinned single crystal samples of the frustrated S=1/2 chain
cuprate LiCu_2O_2. Novel magnetic phase transitions were observed. A spin flop
transition of the spiral spin plane was observed for the field orientations
H||a,b. The second magnetic transition was observed at H~15 T for all three
principal field directions. This high field magnetic phase is discussed as a
collinear spin-modulated phase which is expected for an S=1/2 nearest-neighbor
ferromagnetic and next-nearest-neighbor antiferromagnetic chain system
The use of electronic alerts in primary care computer systems to identify the over-prescription of short-acting beta(2)-agonists in people with asthma: a protocol for a systematic review
The authors wish to thank the Asthma UK Centre for Applied Research for funding this work. AB is an National Institute for Health Research (NIHR) Senior Investigator and additionally was supported by the NIHR Respiratory Disease Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust and Imperial College London. MT was supported by the NIHR Collaboration for Leadership in Applied Health Research and Care (CLAHRC) Wessex, NIHR School of Primary Care Research and NIHR Southampton Biomedical Research Centre. CG was supported by the NIHR CLAHRC North Thames at Bart’s Health NHS Trust
Comparison of resting-state EEG between adults with Down syndrome and typically developing controls
Background:
Down syndrome (DS) is the most common genetic cause of intellectual disability (ID) worldwide. Understanding electrophysiological characteristics associated with DS provides potential mechanistic insights into ID, helping inform biomarkers and targets for intervention. Currently, electrophysiological characteristics associated with DS remain unclear due to methodological differences between studies and inadequate controls for cognitive decline as a potential cofounder.
Methods:
Eyes-closed resting-state EEG measures (specifically delta, theta, alpha, and beta absolute and relative powers, and alpha peak amplitude, frequency and frequency variance) in occipital and frontal regions were compared between adults with DS (with no diagnosis of dementia or evidence of cognitive decline) and typically developing (TD) matched controls (n = 25 per group).
Results:
We report an overall ‘slower’ EEG spectrum, characterised by higher delta and theta power, and lower alpha and beta power, for both regions in people with DS. Alpha activity in particular showed strong group differences, including lower power, lower peak amplitude and greater peak frequency variance in people with DS.
Conclusions:
Such EEG ‘slowing’ has previously been associated with cognitive decline in both DS and TD populations. These findings indicate the potential existence of a universal EEG signature of cognitive impairment, regardless of origin (neurodevelopmental or neurodegenerative), warranting further exploration
Curvilinearity provides additional information to lung clearance index only in a minority of children with early cystic fibrosis lung disease
Curvilinearity, as calculated from multiple-breath washout, is abnormal in a small number of children with cystic fibrosis when other tests are still normal https://bit.ly/3p9QAV4
Fundamental studies of radar scattering from water surfaces: The Lake Washington experiment
The University of Kansas and the University of Washington conducted a series of experiments during July and August of 1989, and July and August of 1990, to study the effects of various geophysical parameters on radar backscatter. The experiments were conducted from a platform in Lake Washington. Measurements of backscattered power and radar range were made by the University of Kansas, and environmental data such as wind speed, wind direction, and air and water temperature were measured by the University of Washington. Results of preliminary data processing are described. Radar data were acquired using two radars, one that operated at C and X bands and another at Ka band. Measurements were made at W and HH antenna polarizations, at different angles of incidence and under various wind conditions. Plots of backscattered power, normalized radar cross section, and wave height, and the Modulation Transfer Functions of selected data are presented
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