1,127 research outputs found
Overview of AWS infrastructure supporting the University Library's Illinois Data Bank, Digital Library and Medusa web applications
An overview of AWS infrastructure supporting the University Library's Illinois Data Bank, Digital Library and Medusa web applications as of February 2020.Ope
Patterns of Dispersion, Movement and Feeding of the Sea Urchin Lytechinus variegatus, and the Potential Implications for Grazing Impact on Live Seagrass
The sea urchin Lytechinus variegatus is a known grazer of both living and dead tissue of turtlegrass, Thalassia testudinum, occasionally denuding large areas of seagrass. Field studies have attempted to assess effects of herbivory on seagrass by enclosing urchins at various densities. However, it is unclear how unrestricted urchins affect seagrass at lower densities more typically observed in the field. This study describes movement, feeding, and distribution of L. variegatus within beds of T. testudinum in St. Joseph Bay, Florida (USA) to quantify this urchin’s impact as a seagrass grazer. Urchins were absent from portions of seagrass beds closest to shore, present at low densities midway across the bed, and at highest densities (up to ~5 individuals/m2) at the offshore edge of the bed. Urchins tended not to aggregate, moved twice as rapidly where seagrass cover was reduced, and moved \u3e 20X faster when placed in areas of open sand. Dead seagrass tissue occurred 4—30X more frequently on oral surfaces than living seagrass tissue. Fecal pellets with dead seagrass tissue were \u3e 3X more common than pellets with live seagrass tissue. Injury to seagrass leaves was more common along dead leaf sections than live sections (\u3e 2—10X). Overall, spatial distributions, movement, and diet indicate that L. variegatus at densities observed in this study would tend to have minimal effects on living seagrass. Episodic periods of denuding grassbeds reported in the literature suggest L. variegatus switches to live seagrass tissue as dead tissue becomes scarce during times of high urchin density
Walking reduces sensorimotor network connectivity compared to standing
BACKGROUND: Considerable effort has been devoted to mapping the functional and effective connectivity of the human brain, but these efforts have largely been limited to tasks involving stationary subjects. Recent advances with high-density electroencephalography (EEG) and Independent Components Analysis (ICA) have enabled study of electrocortical activity during human locomotion. The goal of this work was to measure the effective connectivity of cortical activity during human standing and walking. METHODS: We recorded 248-channels of EEG as eight young healthy subjects stood and walked on a treadmill both while performing a visual oddball discrimination task and not performing the task. ICA parsed underlying electrocortical, electromyographic, and artifact sources from the EEG signals. Inverse source modeling methods and clustering algorithms localized posterior, anterior, prefrontal, left sensorimotor, and right sensorimotor clusters of electrocortical sources across subjects. We applied a directional measure of connectivity, conditional Granger causality, to determine the effective connectivity between electrocortical sources. RESULTS: Connections involving sensorimotor clusters were weaker for walking than standing regardless of whether the subject was performing the simultaneous cognitive task or not. This finding supports the idea that cortical involvement during standing is greater than during walking, possibly because spinal neural networks play a greater role in locomotor control than standing control. Conversely, effective connectivity involving non-sensorimotor areas was stronger for walking than standing when subjects were engaged in the simultaneous cognitive task. CONCLUSIONS: Our results suggest that standing results in greater functional connectivity between sensorimotor cortical areas than walking does. Greater cognitive attention to standing posture than to walking control could be one interpretation of that finding. These techniques could be applied to clinical populations during gait to better investigate neural substrates involved in mobility disorders
Walking reduces sensorimotor network connectivity compared to standing
Abstract
Background
Considerable effort has been devoted to mapping the functional and effective connectivity of the human brain, but these efforts have largely been limited to tasks involving stationary subjects. Recent advances with high-density electroencephalography (EEG) and Independent Components Analysis (ICA) have enabled study of electrocortical activity during human locomotion. The goal of this work was to measure the effective connectivity of cortical activity during human standing and walking.
Methods
We recorded 248-channels of EEG as eight young healthy subjects stood and walked on a treadmill both while performing a visual oddball discrimination task and not performing the task. ICA parsed underlying electrocortical, electromyographic, and artifact sources from the EEG signals. Inverse source modeling methods and clustering algorithms localized posterior, anterior, prefrontal, left sensorimotor, and right sensorimotor clusters of electrocortical sources across subjects. We applied a directional measure of connectivity, conditional Granger causality, to determine the effective connectivity between electrocortical sources.
Results
Connections involving sensorimotor clusters were weaker for walking than standing regardless of whether the subject was performing the simultaneous cognitive task or not. This finding supports the idea that cortical involvement during standing is greater than during walking, possibly because spinal neural networks play a greater role in locomotor control than standing control. Conversely, effective connectivity involving non-sensorimotor areas was stronger for walking than standing when subjects were engaged in the simultaneous cognitive task.
Conclusions
Our results suggest that standing results in greater functional connectivity between sensorimotor cortical areas than walking does. Greater cognitive attention to standing posture than to walking control could be one interpretation of that finding. These techniques could be applied to clinical populations during gait to better investigate neural substrates involved in mobility disorders.http://deepblue.lib.umich.edu/bitstream/2027.42/134578/1/12984_2013_Article_546.pd
Lack of eutrophication in a tallgrass prairie ecosystem over 27 years
Many North American grasslands are receiving atmospheric nitrogen (N) deposition at rates above what are considered critical eutrophication thresholds. Yet, potential changes in grassland function due to anthropogenic N deposition are poorly resolved, especially considering that other dynamic factors such as land use and precipitation can also affect N availability. To better understand whether elevated N deposition has altered ecosystem structure or function in North American grasslands, we analyzed a 27-year record of ecophysiological, community, and ecosystem metrics for an annually burned Kansas tallgrass prairie. Over this time, despite increasing rates of N deposition that are within the range of critical loads for grasslands, there was no evidence of eutrophication. Plant N concentrations did not increase, soil moisture did not decline, forb diversity did not decline, and the relative abundance of dominant grasses did not shift toward more eutrophic species. Neither aboveground primary productivity nor N availability to plants increased. The fates of deposited N in grasslands are still uncertain, and could include management losses through burning and grazing. However, evidence from this grassland indicates that eutrophication of North American grassland ecosystems is not an inevitable consequence of current levels of N deposition
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Enrollment of adolescents and young adults onto SWOG cancer research network clinical trials: A comparative analysis by treatment site and era.
BackgroundFew adolescents and young adults (AYAs, 15-39 years old) enroll onto cancer clinical trials, which hinders research otherwise having the potential to improve outcomes in this unique population. Prior studies have reported that AYAs are more likely to receive cancer care in community settings. The National Cancer Institute (NCI) has led efforts to increase trial enrollment through its network of NCI-designated cancer centers (NCICC) combined with community outreach through its Community Clinical Oncology Program (CCOP; replaced by the NCI Community Oncology Research Program in 2014).MethodsUsing AYA proportional enrollment (the proportion of total enrollments who were AYAs) as the primary outcome, we examined enrollment of AYAs onto SWOG therapeutic trials at NCICC, CCOP, and non-NCICC/non-CCOP sites from 2004 to 2013 by type of site, study period (2004-08 vs 2009-13), and patient demographics.ResultsOverall, AYA proportional enrollment was 10.1%. AYA proportional enrollment decreased between 2004-2008 and 2009-2013 (13.1% vs 8.5%, P < .001), and was higher at NCICCs than at CCOPs and non-NCICC/non-CCOPs (14.1% vs 8.3% and 9.2%, respectively; P < .001). AYA proportional enrollment declined significantly at all three site types. Proportional enrollment of AYAs who were Black or Hispanic was significantly higher at NCICCs compared with CCOPs or non-NCICC/non-CCOPs (11.5% vs 8.8, P = .048 and 11.5% vs 8.6%, P = .03, respectively).ConclusionNot only did community sites enroll a lower proportion of AYAs onto cancer clinical trials, but AYA enrollment decreased in all study settings. Initiatives aimed at increasing AYA enrollment, particularly in the community setting with attention to minority status, are needed
ΔNp73, A Dominant-Negative Inhibitor of Wild-type p53 and TAp73, Is Up-regulated in Human Tumors
p73 has significant homology to p53. However, tumor-associated up-regulation of p73 and genetic data from human tumors and p73-deficient mice exclude a classical Knudson-type tumor suppressor role. We report that the human TP73 gene generates an NH2 terminally truncated isoform. ΔNp73 derives from an alternative promoter in intron 3 and lacks the transactivation domain of full-length TAp73. ΔNp73 is frequently overexpressed in a variety of human cancers, but not in normal tissues. ΔNp73 acts as a potent transdominant inhibitor of wild-type p53 and transactivation-competent TAp73. ΔNp73 efficiently counteracts transactivation function, apoptosis, and growth suppression mediated by wild-type p53 and TAp73, and confers drug resistance to wild-type p53 harboring tumor cells. Conversely, down-regulation of endogenous ΔNp73 levels by antisense methods alleviates its suppressive action and enhances p53- and TAp73-mediated apoptosis. ΔNp73 is complexed with wild-type p53, as demonstrated by coimmunoprecipitation from cultured cells and primary tumors. Thus, ΔNp73 mediates a novel inactivation mechanism of p53 and TAp73 via a dominant-negative family network. Deregulated expression of ΔNp73 can bestow oncogenic activity upon the TP73 gene by functionally inactivating the suppressor action of p53 and TAp73. This trait might be selected for in human cancers
Planet Hunters VII. Discovery of a New Low-Mass, Low-Density Planet (PH3 c) Orbiting Kepler-289 with Mass Measurements of Two Additional Planets (PH3 b and d)
We report the discovery of one newly confirmed planet ( days,
) and mass determinations of two previously
validated Kepler planets, Kepler-289 b ( days,
) and Kepler-289-c ( days,
), through their transit timing variations
(TTVs). We also exclude the possibility that these three planets reside in a
Laplace resonance. The outer planet has very deep (), high
signal-to-noise transits, which puts extremely tight constraints on its host
star's stellar properties via Kepler's Third Law. The star PH3 is a young
( Gyr as determined by isochrones and gyrochronology), Sun-like star
with , , and
K. The middle planet's large TTV amplitude (
hours) resulted either in non-detections or inaccurate detections in previous
searches. A strong chopping signal, a shorter period sinusoid in the TTVs,
allows us to break the mass-eccentricity degeneracy and uniquely determine the
masses of the inner, middle, and outer planets to be ,
, and , which we designate PH3 b, c, and
d, respectively. Furthermore, the middle planet, PH3 c, has a relatively low
density, g/cm for a planet of its mass, requiring a
substantial H/He atmosphere of by mass, and joins a
growing population of low-mass, low-density planets.Comment: 21 pages, 10 figures, 5 tables, accepted into Ap
Kepler Eclipsing Binary Stars. VI. Identification of Eclipsing Binaries in the K2 Campaign 0 Data-set
The original {\it Kepler} mission observed and characterized over 2400
eclipsing binaries in addition to its prolific exoplanet detections. Despite
the mechanical malfunction and subsequent non-recovery of two reaction wheels
used to stabilize the instrument, the {\it Kepler} satellite continues
collecting data in its repurposed {\it K2} mission surveying a series of fields
along the ecliptic plane. Here we present an analysis of the first full
baseline {\it K2} data release: the Campaign 0 data-set. In the 7761 light
curves, we have identified a total of 207 eclipsing binaries. Of these, 97 are
new discoveries that were not previously identified. Our pixel-level analysis
of these objects has also resulted in identification of several false positives
(observed targets contaminated by neighboring eclipsing binaries), as well as
the serendipitous discovery of two short period exoplanet candidates. We
provide catalog cross-matched source identifications, orbital periods,
morphologies and ephemerides for these eclipsing systems. We also describe the
incorporation of the K2 sample into the Kepler Eclipsing Binary
Catalog\footnote{\url{keplerebs.villanova.edu/k2}}, present spectroscopic
follow-up observations for a limited selection of nine systems, and discuss
prospects for upcoming {\it K2} campaigns.Comment: Accepted for publication in MNRAS. 51 pages [20 figures, 8 tables].
Results available online in the Kepler Eclipsing Binary Star Catalog
http://keplerebs.villanova.edu/k
Competition Write Up for IMLS
Following the 2013 Student Competition to develop designs for library mobile applications the library reported the activities of the event to IMLS (Institute of Museum and Library Services).IMLS LG-07-11-0339-11unpublishednot peer reviewe
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