4,051 research outputs found
Posterior Mitral Leaflet Left Atrial Anomalous Chord in the Absence of Surgical Mitral Regurgitation
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108052/1/echo12582.pd
Long-term warming alters the composition of Arctic soil microbial communities
Despite the importance of Arctic soils in the global carbon cycle, we know very little of the impacts of warming on the soil microbial communities that drive carbon and nutrient cycling in these ecosystems. Over a 2-year period, we monitored the structure of soil fungal and bacterial communities in organic and mineral soil horizons in plots warmed by greenhouses for 18 years and in control plots. We found that microbial communities were stable over time but strongly structured by warming. Warming led to significant reductions in the evenness of bacterial communities, while the evenness of fungal communities increased significantly. These patterns were strongest in the organic horizon, where temperature change was greatest and were associated with a significant increase in the dominance of the Actinobacteria and significant reductions in the Gemmatimonadaceae and the Proteobacteria. Greater evenness of the fungal community with warming was associated with significant increases in the ectomycorrhizal fungi, Russula spp., Cortinarius spp., and members of the Helotiales suggesting that increased growth of the shrub Betula nana was an important mechanism driving this change. The shifts in soil microbial community structure appear sufficient to account for warming-induced changes in nutrient cycling in Arctic tundra as climate warm
A Terraced Scanning Superconducting Quantum Interference Device Susceptometer with Sub-Micron Pickup Loops
Superconducting Quantum Interference Devices (SQUIDs) can have excellent spin
sensitivity depending on their magnetic flux noise, pick-up loop diameter, and
distance from the sample. We report a family of scanning SQUID susceptometers
with terraced tips that position the pick-up loops 300 nm from the sample. The
600 nm - 2 um pickup loops, defined by focused ion beam, are integrated into a
12-layer optical lithography process allowing flux-locked feedback, in situ
background subtraction and optimized flux noise. These features enable a
sensitivity of ~70 electron spins per root Hertz at 4K.Comment: See http://stanford.edu/group/moler/publications.html for an
auxiliary document containing additional fabrication details and discussio
Propositionalism without propositions, objectualism without objects
Propositionalism is the view that all intentional states are propositional states, which are states with a propositional content, while objectualism is the view that at least some intentional states are objectual states, which are states with objectual contents, such as objects, properties, and kinds. This paper argues that there are two distinct ways of understanding propositionalism and objectualism: (1) as views about the deep nature of the contents of intentional states, and (2) as views about the superficial character of the contents of intentional states. I argue that we should understand the views in the second way. I also argue that the propositionalism debate is fairly independent from debates over the deep nature of intentionality, and that this has implications for arguments for propositionalism and objectualism from claims about the nature of intentional content. I close with a short discussion of how related points apply to the debate over singular content
Self-Reported Physical Activity and Myocardial Flow Reserve in Postmenopausal Women at Risk for Cardiovascular Disease
Background: Regular exercise protects against coronary heart disease (CHD) events and improves vascular reactivity. Exercise effects on myocardial flow reserve (MFR) are not well studied. Methods: We performed dynamic N-13 ammonia positron emission tomography (PET) in 16 postmenopausal women (60 Ā± 6 years) to measure myocardial blood flow (MBF) and MFR. We also obtained information from each woman on her self-reported physical activity. Results: Of the 16 patients, 6 reported moderate regular physical activity, and 10 did not. Women who reported regular, at least moderate physical activity had a higher percentage increase in adenosine MBF from rest compared with women who did not exercise (268% vs. 129%, p = 0.04) and had a significantly higher mean maximal MFR (3.68 vs. 2.29, p = 0.04). Conclusions: These findings provide further mechanistic support for the beneficial cardiovascular effects of exercise.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63137/1/jwh.2006.15.45.pd
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Precipitation regime change in Western North America: The role of Atmospheric Rivers.
Daily precipitation in California has been projected to become less frequent even as precipitation extremes intensify, leading to uncertainty in the overall response to climate warming. Precipitation extremes are historically associated with Atmospheric Rivers (ARs). Sixteen global climate models are evaluated for realism in modeled historical AR behavior and contribution of the resulting daily precipitation to annual total precipitation over Western North America. The five most realistic models display consistent changes in future AR behavior, constraining the spread of the full ensemble. They, moreover, project increasing year-to-year variability of total annual precipitation, particularly over California, where change in total annual precipitation is not projected with confidence. Focusing on three representative river basins along the West Coast, we show that, while the decrease in precipitation frequency is mostly due to non-AR events, the increase in heavy and extreme precipitation is almost entirely due to ARs. This research demonstrates that examining meteorological causes of precipitation regime change can lead to better and more nuanced understanding of climate projections. It highlights the critical role of future changes in ARs to Western water resources, especially over California
The VWFA Is the Home of Orthographic Learning When Houses Are Used as Letters
Learning to read specializes a portion of the left mid-fusiform cortex for printed word recognition, the putative visual word form area (VWFA). This study examined whether a VWFA specialized for English is sufficiently malleable to support learning a perceptually atypical second writing system. The study utilized an artificial orthography, HouseFont, in which house images represent English phonemes. House images elicit category-biased activation in a spatially distinct brain region, the so-called parahippocampal place area (PPA). Using house images as letters made it possible to test whether the capacity for learning a second writing system involves neural territory that supports reading in the first writing system, or neural territory tuned for the visual features of the new orthography. Twelve human adults completed two weeks of training to establish basic HouseFont reading proficiency and underwent functional neuroimaging pre and post-training. Analysis of three functionally defined regions of interest (ROIs), the VWFA, and left and right PPA, found significant pre-training versus post-training increases in response to HouseFont words only in the VWFA. Analysis of the relationship between the behavioral and neural data found that activation changes from pre-training to post-training within the VWFA predicted HouseFont reading speed. These results demonstrate that learning a new orthography utilizes neural territory previously specialized by the acquisition of a native writing system. Further, they suggest VWFA engagement is driven by orthographic functionality and not the visual characteristics of graphemes, which informs the broader debate about the nature of category-specialized areas in visual association cortex
Comprehensive and user-analytics-friendly cancer patient database for physicians and researchers
Nuanced cancer patient care is needed, as the development and clinical course
of cancer is multifactorial with influences from the general health status of
the patient, germline and neoplastic mutations, co-morbidities, and
environment. To effectively tailor an individualized treatment to each patient,
such multifactorial data must be presented to providers in an easy-to-access
and easy-to-analyze fashion. To address the need, a relational database has
been developed integrating status of cancer-critical gene mutations, serum
galectin profiles, serum and tumor glycomic profiles, with clinical,
demographic, and lifestyle data points of individual cancer patients. The
database, as a backend, provides physicians and researchers with a single,
easily accessible repository of cancer profiling data to aid-in and enhance
individualized treatment. Our interactive database allows care providers to
amalgamate cohorts from these groups to find correlations between different
data types with the possibility of finding "molecular signatures" based upon a
combination of genetic mutations, galectin serum levels, glycan compositions,
and patient clinical data and lifestyle choices. Our project provides a
framework for an integrated, interactive, and growing database to analyze
molecular and clinical patterns across cancer stages and subtypes and provides
opportunities for increased diagnostic and prognostic power.Comment: 7 pages, 12 figures, peer reviewed and accepted in "International
Conference on Computational Science and Computational Intelligence (CSCI 22)
Small-particle Inhaled Corticosteroid as First-line or Step-up Controller Therapy in Childhood Asthma
Copyright Ā© 2015 The Authors. Published by Elsevier Inc. All rights reserved.Peer reviewedPublisher PD
āNone of Us Sets Out To Hurt Peopleā: The Ethical Geographer and Geography Curricula in Higher Education
This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Geography in Higher Education on 22nd January 2008, available online: https://doi.org/10.1080/03098260701731462This paper examines ethics in learning and teaching geography in higher education. It proposes a pathway towards curriculum and pedagogy that better incorporates ethics in university geography education. By focusing on the central but problematic relationships between (i) teaching and learning on the one hand and research on the other, and (ii) ethics and geography curricula, the authorsā reflections illustrate how ethics may be better recognized within those curricula. They discuss issues affecting teaching and learning about ethics in geography, and through identification of a range of examples identify ways to enhance the integration of ethical issues into university geography curricula
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