344 research outputs found

    Defining Western Prairie Fringed Orchid (Platanthera Praeclara) Habitat

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    Terrestrial orchids are at the forefront of the discussion about anthropogenically-driven extinction with more species threatened globally than any other plant family, mostly because of loss of habitat. The Western Prairie Fringed Orchid (Platanthera praeclara) is a threatened species found on the Sheyenne National Grassland in southeast North Dakota, USA. This conservation area that is a vital refuge for this species is subject to management for multiple uses including livestock grazing and recreation. Orchids are subject to continuous monitoring, but knowledge of the relationship between landscape indicators and orchid locations is limited. Research is needed to provide a greater understanding of the landscape relative to orchid habitat to develop conservation management strategies suited to dealing with threats arising from future interactions between land management and use, and climate change. The spatial distribution of orchid habitat was defined using a suite of indicators that characterize topography, moisture, and vegetation cover and compared with orchid point-based field observations. High resolution infrared imagery, a LiDAR-derived DEM, and well observations were used to characterize landscape properties. The NDVI (a measure of vegetation cover), the Topographic Wetness Index (TWI: a measure of moisture on the landscape), the Topographic Position Index (TPI: a measure of position on the landscape), and the depth to groundwater (a measure of the depth from the land surface to the groundwater surface) provided the best set of indicators of orchid habitat. Comparison between orchid locations and landscape indicators identified orchid metrics (±2 σ) used to classify landscape indicators which were combined to create orchid habitat maps. This study supports that distribution of orchid habitat are influenced by the selected landscape indicators, each providing important information to the analysis. Comparison of orchid metrics with groundwater elevations showed that orchids generally occurred on average 1.01 ±0.43 (2σ) meters above the water table. TWI and TPI demonstrated that orchids occur near margins of flow paths and near foot and toe slopes of slight elevations changes. NDVI classified vegetation cover and excluded agricultural land use. Landscape-scale analysis of orchid habitat identifies areas most in need of protection or restoration, and monitoring

    A Device for Noninvasive Assessment of Vascular Impairment Risk in the Lower Extremity

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    The repeatability and resolution of the clinical gold standard of vascular assessment, the ankle-brachial index (ABI), was compared to that of a new device that dynamically assesses tissue perfusion during external loading utilizing laser Doppler flowmetry. Eight subjects of varying levels of vascular impairment were tested in successive weeks using two different sites on the subject\u27s posterior calf. These new measures included the perfusion decrease as well as the unloading delay during cyclic loading. Some new dynamic tissue perfusion measures demonstrated comparable levels of reproducibility with the ABI (e.g., 10%-20%). Only the unloading delay showed potentially enhanced resolution over ABI measures. The perfusion decrease showed little resolution, and the remaining parameters exhibited too great variability (25%-90%). The unloading delay associated with the reperfusion response during cyclic loading displayed the greatest combination of reproducibility and differentiation between subject groups of varying levels of vascular impairment. The preliminary results of this pilot study were also used to estimate sample sizes necessary to detect possible significant (

    Early College, Early Success: Early College High School Initiative Impact Study

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    In 2002, the Bill & Melinda Gates Foundation launched the ECHSI with the primary goal of increasing the opportunity for underserved students to earn a postsecondary credential. To achieve this goal, Early Colleges provide underserved students with exposure to, and support in, college while they are in high school. Early Colleges partner with colleges and universities to offer all students an opportunity to earn an associate's degree or up to two years of college credits toward a bachelor's degree during high school at no or low cost to the students. The underlying assumption is that engaging underrepresented students in a rigorous high school curriculum tied to the incentive of earning college credit will motivate them and increase their access to additional postsecondary education and credentials after high school. Since 2002, more than 240 Early Colleges have opened nationwideThis study focused on the impact of Early Colleges. It addressed two questions:1. Do Early College students have better outcomes than they would have had at other high schools?2. Does the impact of Early Colleges vary by student background characteristics (e.g., gender and family income)? To answer these questions, we conducted a lottery-based randomized experiment, taking advantage of the fact that some Early Colleges used lotteries in their admissions processes. By comparing the outcomes for students who participated in admissions lotteries and were offered enrollment with the outcomes for students who participated in the lotteries but were not offered enrollment, we can draw causal conclusions about the impact of Early Colleges.The primary student outcomes for this study were high school graduation, college enrollment, and college degree attainment. We also examined students' high school and college experiences. Data on student background characteristics and high school outcomes came from administrative records from schools, districts, and states; data on collegeoutcomes came from the National Student Clearinghouse (NSC); and data on high school and college experiences and intermediate outcomes such as college credit accrual camefrom a student surveyWe assessed the impact of Early Colleges on these outcomes for a sample of 10 Early Colleges that did the following:-Enrolled students in grades 9 -- 12 and had high school graduates in the study years (2005 -- 2011)-Used lotteries as part of the admission processes in at least one of the study cohorts (students who entered ninth grade in 2005 -- 06, 2006 -- 07, or 2007 -- 08)-Retained the lottery recordsEight of the 10 Early Colleges in the study were included in the student survey. The overall study sample included 2,458 students and the survey sample included 1,294 students. The study extended through three years past high school

    Federated Searching Interface Techniques for Heterogeneous OAI Repositories

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    Federating repositories by harvesting heterogeneous collections with varying degrees of metadata richness poses a number of challenging issues: (1) how to address the lack of uniform control for various metadata fields in terms of building a rich unified search interface, and (2) how easily new collections and freshly harvested data in existing repositories can be incorporated into the federation supporting a unified interface? This paper focuses on the approaches taken to address these issues in Arc, an Open Archives Initiative compliant federated digital library. At present Arc contains over 1M metadata records from 75 data providers from various subject domains. Analysis of these heterogeneous collections indicates that controlled vocabularies and values are widely used in most repositories. Usage is extremely variable, however. In Arc we solve the problem by implementing an advanced searching interface that allows users to search and select in specific fields with data we construct from the harvested metadata, and also by an interactive search for the subject field. As the metadata records are incrementally harvested we address how to build these services over frequently added new collections and harvested data. The initial result is promising, showing the benefits of immediate feedback to the user in enhancing the search experience as well as in increasing the precision of the user\u27s search

    The Double Disparity Facing Rural Local Health Departments

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    Residents of rural jurisdictions face significant health challenges, including some of the highest rates of risky health behaviors and worst health outcomes of any group in the country. Rural communities are served by smaller local health departments (LHDs) that are more understaffed and underfunded than their suburban and urban peers. As a result of history and current need, rural LHDs are more likely than their urban peers to be providers of direct health services, leading to relatively lower levels of population-focused activities. This review examines the double disparity faced by rural LHDs and their constituents: pervasively poorer health behaviors and outcomes and a historical lack of investment by local, state, and federal public health entities

    A Profile of Tribal Health Departments

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    This study uses data to analyze the impacts of Tribal health departments in improving health status and reducing health disparities.

    The Negative Feedback-Loop between the Oncomir Mir-24-1 and Menin Modulates the Men1 Tumorigenesis by Mimicking the “Knudson’s Second Hit”

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    Multiple endocrine neoplasia type 1 (MEN1) syndrome is a rare hereditary cancer disorder characterized by tumors of the parathyroids, of the neuroendocrine cells, of the gastro-entero-pancreatic tract, of the anterior pituitary, and by non-endocrine neoplasms and lesions. MEN1 gene, a tumor suppressor gene, encodes menin protein. Loss of heterozygosity at 11q13 is typical of MEN1 tumors, in agreement with the Knudson’s two-hit hypothesis. In silico analysis with Target Scan, Miranda and Pictar-Vert softwares for the prediction of miRNA targets indicated miR-24-1 as capable to bind to the 3′UTR of MEN1 mRNA. We investigated this possibility by analysis of miR-24-1 expression profiles in parathyroid adenomatous tissues from MEN1 gene mutation carriers, in their sporadic non-MEN1 counterparts, and in normal parathyroid tissue. Interestingly, the MEN1 tumorigenesis seems to be under the control of a “negative feedback loop” between miR-24-1 and menin protein, that mimics the second hit of Knudson’s hypothesis and that could buffer the effect of the stochastic factors that contribute to the onset and progression of this disease. Our data show an alternative way to MEN1 tumorigenesis and, probably, to the “two-hit dogma”. The functional significance of this regulatory mechanism in MEN1 tumorigenesis is also the basis for opening future developments of RNA antagomir(s)-based strategies in the in vivo control of tumorigenesis in MEN1 carriers

    The Morphological Butcher-Oemler effect in the SDSS Cut&Enhance Galaxy Cluster Catalog

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    We investigate the evolution of the fractions of late type cluster galaxies as a function of redshift, using one of the largest, most uniform cluster samples available. The sample consists of 514 clusters of galaxies in the range 0.02<z<0.3 from the Sloan Digital Sky Survey Cut & Enhance galaxy cluster catalog. This catalog was created using a single automated cluster finding algorithm on uniform data from a single telescope, with accurate CCD photometry, thus, minimizing selection biases. We use four independent methods to analyze the evolution of the late type galaxy fraction. Specifically, we select late type galaxies based on: restframe g-r color, u-r color, galaxy profile fitting and concentration index. The first criterion corresponds to the one used in the classical Butcher-Oemler analyses. The last three criteria are more sensitive to the morphological type of the galaxies. In all four cases, we find an increase in the fraction of late type galaxies with increasing redshift, significant at the 99.9% level. The results confirm that cluster galaxies do change colors with redshift (the Butcher-Oemler effect) and, in addition, they change their morphology to later-type toward higher redshift -- indicating a morphological equivalent of the Butcher-Oemler effect. We also find a tendency of richer clusters to have lower fractions of late type galaxies. The trend is consistent with a ram pressure stripping model, where richer clusters have more effective ram pressure due to their higher temperature.Comment: 44 pages, 15 figures, accepted for PAS
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