1,719 research outputs found
Manifestly Haraway by Donna J. Haraway
Review of Donna J. Haraway\u27s Manifestly Haraway
A New Index for Predicting Catastrophes by Madhur Anand
A Review of Madhur Anand\u27s A New Index for Predicting Catastrophes
Downhill running impairs activation and strength of the elbow flexors
PURPOSE: The aim of this study was to determine if knee extensor injury induced by 1 h of downhill running attenuated force production in uninjured skeletal muscle (e.g., elbow flexors). METHODS: Recreationally active subjects (n = 12) completed a two group (injury vs control) repeated measures design with the injury group running downhill for 1 h and the control group performing only the measurement procedures. Strength and percent voluntary muscle activation were measured using an isokinetic dynamometer and electrical stimulation of the elbow flexors and knee extensors before and after a fatigue protocol at the following time points in relation to the downhill run: 15 min pre, 15 min post, 24 h post, and 48 h post. Blood samples were collected at the same time points to measure IL-1β and TNF-α concentrations. RESULTS: Knee extensor strength was significantly reduced by 53.5±9.9% immediately post-injury and remained reduced for up to 48 h in the injury group. Elbow flexor strength was significantly reduced immediately and 24 h post-injury by 13.2±3.9% and 17.3±4.0% respectively in the injury group. Elbow flexor electrically stimulated strength was not found to be different at any time point (P = 0.561). Elbow flexor activation was significantly reduced compared to control at 24 and 48 h post-injury by 22.9±9.1% and 13.5±5.7% respectively. No differences were observed in IL-1β or TNF-α between groups. CONCLUSION: A 1 h downhill run significantly injured the knee extensors. The elbow flexor muscles remained uninjured based on electrically stimulated strength, but voluntary strength of these muscles was impaired due to reduced activation. This suggests an injury to the knee extensors can impair strength in uninjured muscles by reducing voluntary activation. The mechanism behind this reduction remains undetermined.
INDEX WORDS: Downhill running, Muscle injury, Central nervous system, Inflammatio
New challenges in studying nutrition-disease interactions in the developing world.
Latest estimates indicate that nutritional deficiencies account for 3 million child deaths each year in less-developed countries. Targeted nutritional interventions could therefore save millions of lives. However, such interventions require careful optimization to maximize benefit and avoid harm. Progress toward designing effective life-saving interventions is currently hampered by some serious gaps in our understanding of nutrient metabolism in humans. In this Personal Perspective, we highlight some of these gaps and make some proposals as to how improved research methods and technologies can be brought to bear on the problems of undernourished children in the developing world
Photometric redshifts from reconstructed QSO templates
From SDSS commissioning photometric and spectroscopic data, we investigate
the utility of photometric redshift techniques to the task of estimating QSO
redshifts. We consider empirical methods (e.g. nearest-neighbor searches and
polynomial fitting), standard spectral template fitting and hybrid approaches
(i.e. training spectral templates from spectroscopic and photometric
observations of QSOs). We find that in all cases, due to the presence of strong
emission-lines within the QSO spectra, the nearest-neighbor and template
fitting methods are superior to the polynomial fitting approach. Applying a
novel reconstruction technique, we can, from the SDSS multicolor photometry,
reconstruct a statistical representation of the underlying SEDs of the SDSS
QSOs. Although, the reconstructed templates are based on only broadband
photometry the common emission lines present within the QSO spectra can be
recovered in the resulting spectral energy distributions. The technique should
be useful in searching for spectral differences among QSOs at a given redshift,
in searching for spectral evolution of QSOs, in comparing photometric redshifts
for objects beyond the SDSS spectroscopic sample with those in the well
calibrated photometric redshifts for objects brighter than 20th magnitude and
in searching for systematic and time variable effects in the SDSS broad band
photometric and spectral photometric calibrations.Comment: 21 pages, 9 figures, LaTeX AASTeX, submitted to A
Genetic Mosaic Analysis Indicates That the Bulb Region of Coat Hair Follicles Contains a Resident Population of Several Active Multipotent Epithelial Lineage Progenitors
AbstractThe hair follicle represents an excellent model system for exploring the properties of lineage-forming units in a dynamic epithelium containing multiple cell types. During its growth (anagen) phase, the proximal–distal axis of the mouse coat hair (pelage) follicle provides a historical record of all epithelial lineages generated from its resident stem cell population. An unresolved question in the field is whether the bulb region of anagen pelage follicles contains multipotential progenitors and whether their individual contribution to cellular census fluctuates over time. To address this issue, chimeric follicles were harvested in midanagen from three types of genetic mosaic mouse models. Analysis of the distribution of genotypic markers, including digital three-dimensional reconstruction of serially sectioned chimeric follicles, revealed that on average the bulb contains four or fewer active progenitors, each capable of giving rise to all six follicular epithelial fates. Moreover, analysis of mosaic pelage, as well as cultured whisker follicles provided evidence that bulb-associated progenitors can give rise to expanding descendant clones during midanagen, leading to the conclusion that the bulb contains dormant or symmetrically dividing stem cells. This latter feature resembles the behavior of hematopoietic stem cells after bone marrow transplantation, and raises the question of whether this property may be shared by stem cells in other self-renewing epithelia
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Where Next for Microbiome Research?
The development of high-throughput sequencing technologies has transformed our capacity to investigate the composition and dynamics of the microbial communities that populate diverse habitats. Over the past decade, these advances have yielded an avalanche of metagenomic data. The current stage of “van Leeuwenhoek”–like cataloguing, as well as functional analyses, will likely accelerate as DNA and RNA sequencing, plus protein and metabolic profiling capacities and computational tools, continue to improve. However, it is time to consider: what’s next for microbiome research? The short pieces included here briefly consider the challenges and opportunities awaiting microbiome research
Efficient Photometric Selection of Quasars from the Sloan Digital Sky Survey: 100,000 z<3 Quasars from Data Release One
We present a catalog of 100,563 unresolved, UV-excess (UVX) quasar candidates
to g=21 from 2099 deg^2 of the Sloan Digital Sky Survey (SDSS) Data Release One
(DR1) imaging data. Existing spectra of 22,737 sources reveals that 22,191
(97.6%) are quasars; accounting for the magnitude dependence of this
efficiency, we estimate that 95,502 (95.0%) of the objects in the catalog are
quasars. Such a high efficiency is unprecedented in broad-band surveys of
quasars. This ``proof-of-concept'' sample is designed to be maximally
efficient, but still has 94.7% completeness to unresolved, g<~19.5, UVX quasars
from the DR1 quasar catalog. This efficient and complete selection is the
result of our application of a probability density type analysis to training
sets that describe the 4-D color distribution of stars and spectroscopically
confirmed quasars in the SDSS. Specifically, we use a non-parametric Bayesian
classification, based on kernel density estimation, to parameterize the color
distribution of astronomical sources -- allowing for fast and robust
classification. We further supplement the catalog by providing photometric
redshifts and matches to FIRST/VLA, ROSAT, and USNO-B sources. Future work
needed to extend the this selection algorithm to larger redshifts, fainter
magnitudes, and resolved sources is discussed. Finally, we examine some science
applications of the catalog, particularly a tentative quasar number counts
distribution covering the largest range in magnitude (14.2<g<21.0) ever made
within the framework of a single quasar survey.Comment: 35 pages, 11 figures (3 color), 2 tables, accepted by ApJS; higher
resolution paper and ASCII version of catalog available at
http://sdss.ncsa.uiuc.edu/qso/nbckde
A Unified Framework for the Infection Dynamics of Zoonotic Spillover and Spread.
A considerable amount of disease is transmitted from animals to humans and many of these zoonoses are neglected tropical diseases. As outbreaks of SARS, avian influenza and Ebola have demonstrated, however, zoonotic diseases are serious threats to global public health and are not just problems confined to remote regions. There are two fundamental, and poorly studied, stages of zoonotic disease emergence: 'spillover', i.e. transmission of pathogens from animals to humans, and 'stuttering transmission', i.e. when limited human-to-human infections occur, leading to self-limiting chains of transmission. We developed a transparent, theoretical framework, based on a generalization of Poisson processes with memory of past human infections, that unifies these stages. Once we have quantified pathogen dynamics in the reservoir, with some knowledge of the mechanism of contact, the approach provides a tool to estimate the likelihood of spillover events. Comparisons with independent agent-based models demonstrates the ability of the framework to correctly estimate the relative contributions of human-to-human vs animal transmission. As an illustrative example, we applied our model to Lassa fever, a rodent-borne, viral haemorrhagic disease common in West Africa, for which data on human outbreaks were available. The approach developed here is general and applicable to a range of zoonoses. This kind of methodology is of crucial importance for the scientific, medical and public health communities working at the interface between animal and human diseases to assess the risk associated with the disease and to plan intervention and appropriate control measures. The Lassa case study revealed important knowledge gaps, and opportunities, arising from limited knowledge of the temporal patterns in reporting, abundance of and infection prevalence in, the host reservoir.Natural Environment Research Council (project no.: NEJ001570-1), Department for International Development, Economic and Social Research Council, National Institute for Health Research, Science and Technology Directorate, Department of Homeland Security, Fogarty International Center USA, European Union FP7 (project ANTIGONE (contract number 278976)), Royal Society (Wolfson Research Merit Award), Alborada Trust, US National Institute of Health (P20GM103501, BAANIAID-DAIT-NIHQI2008031, HHSN272201000022C, HHSN272200900049C, 1U19AI109762, 1R01AI104621, 2R44AI088843), USAID/NIH PEER Health grant.This is the final version of the article. It first appeared from the Public Library of Science via http://dx.doi.org/10.1371/journal.pntd.000495
CCAT-prime: a novel telescope for submillimeter astronomy
The CCAT-prime telescope is a 6-meter aperture, crossed-Dragone telescope,
designed for millimeter and sub-millimeter wavelength observations. It will be
located at an altitude of 5600 meters, just below the summit of Cerro
Chajnantor in the high Atacama region of Chile. The telescope's unobscured
optics deliver a field of view of almost 8 degrees over a large, flat focal
plane, enabling it to accommodate current and future instrumentation fielding
>100k diffraction-limited beams for wavelengths less than a millimeter. The
mount is a novel design with the aluminum-tiled mirrors nested inside the
telescope structure. The elevation housing has an integrated shutter that can
enclose the mirrors, protecting them from inclement weather. The telescope is
designed to co-host multiple instruments over its nominal 15 year lifetime. It
will be operated remotely, requiring minimum maintenance and on-site activities
due to the harsh working conditions on the mountain. The design utilizes
nickel-iron alloy (Invar) and carbon-fiber-reinforced polymer (CFRP) materials
in the mirror support structure, achieving a relatively temperature-insensitive
mount. We discuss requirements, specifications, critical design elements, and
the expected performance of the CCAT-prime telescope. The telescope is being
built by CCAT Observatory, Inc., a corporation formed by an international
partnership of universities. More information about CCAT and the CCAT-prime
telescope can be found at www.ccatobservatory.org.Comment: Event: SPIE Astronomical Telescope + Instrumentation, 2018, Austin,
Texas, USA; Proceedings Volume 10700, Ground-based and Airborne Telescopes
VII; 107005X (2018
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