1,746 research outputs found
Nonresponse of native Cottonwood trees to water additions during summer drought
Studies have demonstrated that some riparian trees may switch their reliance on surface soil water (unsaturated or vadose zone) to groundwater (saturated zone) sources during the growing season in association with changes in moisture availability. A closely related question is: How do these trees respond to pulse increases in water availability in previously dry zones? We tested the whole-tree physiological response of 6 natural Populus genotypes to water additions during the peak of summer drought in northern Utah, USA. We found clear evidence that trees were insensitive to water additions to the surface soil that were twice the magnitude of whole-tree transpiration rates. Our results suggest that some cottonwoods may have little immediate transpiration of leaf conductance response to pulse soil moisture increases. This lack of response may be related to water-use strategy associated with regional climate patterns (i.e. genetic or environmental programming), cavitation recovery, or other physical determinants of water use such as depth to groundwater. Our data suggest that it is important to consider potential nonresponsiveness to changes in soil water availability when evaluating the impact of climate change on these important and productive ecosystems
Concert recording 2021-11-16
[Track 1]. Cello Suite No. 4. Prelude / J.S. Bach -- [Track 2]. Black Mary / Shelley Washington -- [Track 3]. Ali / Alex Mincek -- [Track 4]. Premiere Quatour. Andante / Jean Baptiste Singelee -- [Track 5]. Variations Saxophoniques / Fernande Decruck -- [Track 6]. Mountain Roads. Overture / David Maslanka -- [Track 7]. Passaggi. Bugarka / Pepito Ros -- [Track 8]. Blueprint / Caroline Shaw ; arranged by Dylan Matheny -- [Track 9]. Lo Yisa Goy / Stacy Garrop -- [Track 10]. First Suite in E-flat. Chaconne / Gustav Holst ; arranged by Christian T. Anderson
Inference with interference between units in an fMRI experiment of motor inhibition
An experimental unit is an opportunity to randomly apply or withhold a
treatment. There is interference between units if the application of the
treatment to one unit may also affect other units. In cognitive neuroscience, a
common form of experiment presents a sequence of stimuli or requests for
cognitive activity at random to each experimental subject and measures
biological aspects of brain activity that follow these requests. Each subject
is then many experimental units, and interference between units within an
experimental subject is likely, in part because the stimuli follow one another
quickly and in part because human subjects learn or become experienced or
primed or bored as the experiment proceeds. We use a recent fMRI experiment
concerned with the inhibition of motor activity to illustrate and further
develop recently proposed methodology for inference in the presence of
interference. A simulation evaluates the power of competing procedures.Comment: Published by Journal of the American Statistical Association at
http://www.tandfonline.com/doi/full/10.1080/01621459.2012.655954 . R package
cin (Causal Inference for Neuroscience) implementing the proposed method is
freely available on CRAN at https://CRAN.R-project.org/package=ci
Evidence of Glycolysis Up-Regulation and Pyruvate Mitochondrial Oxidation Mismatch During Mechanical Unloading of the Failing Human Heart: Implications for Cardiac Reloading and Conditioning
This study sought to investigate the effects of mechanical unloading on myocardial energetics and the metabolic perturbation of heart failure (HF) in an effort to identify potential new therapeutic targets that could enhance the unloading-induced cardiac recovery. The authors prospectively examined paired human myocardial tissue procured from 31 advanced HF patients at left ventricular assist device (LVAD) implant and at heart transplant plus tissue from 11 normal donors. They identified increased post-LVAD glycolytic metabolites without a coordinate increase in early, tricarboxylic acid (TCA) cycle intermediates. The increased pyruvate was not directed toward the mitochondria and the TCA cycle for complete oxidation, but instead, was mainly converted to cytosolic lactate. Increased nucleotide concentrations were present, potentially indicating increased flux through the pentose phosphate pathway. Evaluation of mitochondrial function and structure revealed a lack of post-LVAD improvement in mitochondrial oxidative functional capacity, mitochondrial volume density, and deoxyribonucleic acid content. Finally, post-LVAD unloading, amino acid levels were found to be increased and could represent a compensatory mechanism and an alternative energy source that could fuel the TCA cycle by anaplerosis. In summary, the authors report evidence that LVAD unloading induces glycolysis in concert with pyruvate mitochondrial oxidation mismatch, most likely as a result of persistent mitochondrial dysfunction. These findings suggest that interventions known to improve mitochondrial biogenesis, structure, and function, such as controlled cardiac reloading and conditioning, warrant further investigation to enhance unloading-induced reverse remodeling and cardiac recovery
Searchlight-based multi-voxel pattern analysis of fMRI by cross-validated MANOVA
Multi-voxel pattern analysis (MVPA) is a fruitful and increasingly popular complement to traditional univariate methods of analyzing neuroimaging data. We propose to replace the standard ‘decoding’ approach to searchlight-based MVPA, measuring the performance of a classifier by its accuracy, with a method based on the multivariate form of the general linear model. Following the well-established methodology of multivariate analysis of variance (MANOVA), we define a measure that directly characterizes the structure of multi-voxel data, the pattern distinctness D. Our measure is related to standard multivariate statistics, but we apply cross-validation to obtain an unbiased estimate of its population value, independent of the amount of data or its partitioning into ‘training’ and ‘test’ sets. The estimate can therefore serve not only as a test statistic, but also as an interpretable measure of multivariate effect size. The pattern distinctness generalizes the Mahalanobis distance to an arbitrary number of classes, but also the case where there are no classes of trials because the design is described by parametric regressors. It is defined for arbitrary estimable contrasts, including main effects (pattern differences) and interactions (pattern changes). In this way, our approach makes the full analytical power of complex factorial designs known from univariate fMRI analyses available to MVPA studies. Moreover, we show how the results of a factorial analysis can be used to obtain a measure of pattern stability, the equivalent of ‘cross-decoding’
Beam Test Results of the RADiCAL -- a Radiation Hard Innovative EM Calorimeter
High performance calorimetry conducted at future hadron colliders, such as
the FCC-hh, poses a significant challenge for applying current detector
technologies due to unprecedented beam luminosities and radiation fields.
Solutions include developing scintillators that are capable of separating
events at the sub-fifty picosecond level while also maintaining performance
after extreme and constant neutron and ionizing radiation exposure. The RADiCAL
is an approach that incorporates radiation tolerant materials in a sampling
'shashlik' style calorimeter configuration, using quartz capillaries filled
with organic liquid or polymer-based wavelength shifters embedded in layers of
tungsten plates and LYSO crystals. This novel design intends to address the
Priority Research Directions (PRD) for calorimetry listed in the DOE Basic
Research Needs (BRN) workshop for HEP Instrumentation. Here we report
preliminary results from an experimental run at the Fermilab Test Beam Facility
in June 2022. These tests demonstrate that the RADiCAL concept is capable of <
50 ps timing resolution.Comment: 5 pages, 10 figures, SCINT22 conferenc
Meta-Analysis of the Association between Transforming Growth Factor-Beta Polymorphisms and Complications of Coronary Heart Disease
Objective: To investigate the association between common transforming growth factor beta (TGF-β) single nucleotide polymorphisms (SNP) and significant complications of coronary heart disease (CHD).\ud
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Method: We performed a meta-analysis of published case-control studies assessing the association of TGF-β SNPs with a range of CHD complications. A random effects model was used to calculate odds ratios and confidence intervals. Analyses were conducted for additive, dominant and recessive modes of inheritance.\ud
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Results: Six studies involving 5535 cases and 2970 controls examining the association of common SNPs in TGF-β1 with CHD were identified. Applying a dominant model of inheritance, three TGF-β1 SNPs were significantly associated with CHD complications: The T alleles of rs1800469 (OR = 1.125, 95% CI 1.016–1.247, p = 0.031) and rs1800470 (OR = 1.146, 95% CI 1.026–1.279, p = 0.021); and the C allele of rs1800471 (OR = 1.207, 95% CI 1.037–1.406, p = 0.021).\ud
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Conclusion: This meta-analysis suggests that common genetic polymorphisms in TGF-β1 are associated with complications of CHD
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