2,222 research outputs found

    Habitat Specificity in Land Snails

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    Validity of the activPAL3 activity monitor in people moderately affected by Multiple Sclerosis

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    Background: Walking is the primary form of physical activity performed by people with Multiple Sclerosis (MS), therefore it is important to ensure the validity of tools employed to measure walking activity. The aim of this study was to assess the criterion validity of the activPAL3 activity monitor during overground walking in people with MS.\ud Methods: Validity of the activPAL3 accelerometer was compared to video observation in 20 people moderately affected by MS. Participants walked 20-30m twice along a straight quiet corridor at a comfortable speed.\ud Results: Inter-rater reliability of video observations was excellent (all intraclass correlations > 0.99). The mean difference (activPAL3- mean of raters) was -4.70 ± 9.09, -4.55 s ± 10.76 and 1.11 s ± 1.11 for steps taken, walking duration and upright duration respectively. These differences represented 8.7, 10.0 and 1.8% of the mean for each measure respectively. The activPAL3 tended to underestimate steps taken and walking duration in those who walked at cadences of ≀ 38 steps/minute by 60% and 47% respectively.\ud Discussion: The activPAL3 is valid for measuring walking activity in people moderately affected by MS. It is accurate for upright duration regardless of cadence. In participants with slow walking cadences, outcomes of steps taken and walking duration should be interpreted with caution

    VEGETATION FIRE FUELS MAPPING IN THE SAN DIEGO CITY CANYONS – A METHOD COMPARISON

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    Fire risk is a major threat to life, property and natural resources in southern California. Recent fire disasters occurred in autumn 2003 and 2007. Fire risk management deals with these hazards, input data are collected, analyzed and evaluated. One of the most important input data is the vegetation density in the endangered areas. Here we describe methods to map vegetation density forming five hazard classes. The main objective of this study is to explore the benefits of using remote sensed data for the accurate classification of vegetation in San Diego city canyons. Three very high resolution remote sensing data sets (< 1 m) were used in comparison: scanned color infrared film (CIR) airborne, digital multi-spectral airborne (ADS40) and digital multi-spectral satellite imagery (QuickBird). Different classification approaches (e.g. pixel-based, segment-based and knowledge-based) were tested and analyzed to separate the vegetation into five hazard classes. Accuracy assessment indicated low overall accuracies of 58 % on average. With regard to an optimized classification result in particular unsupervised and segment-based classification can be recommended. The overall accuracy for these two methods reached around 62 %. The use of specially selected reference areas for validation helped to increase the accuracies up to 81 %. Also a separating between three instead of five different hazard classes resulted in accuracies around 80 %. Furthermore it could be shown that all three data sets can be used for successful classification procedures. The resulting fire risk maps can help to reduce or prevent fire hazards. The maps are a basis for the brush management of the Fir

    Squarks Below the Z

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    We investigate the possibility that the difference between the measurements of α3(MZ)\alpha_3(M_Z) from the hadronic branching ratio of the Z0Z^0 and the world average of other measurements is due to the decay of the Z0Z^0 into quark, anti-squark, and gluino. Consequences for supersymmetry breaking models are discussed.Comment: 9 pages, 4 figures not include

    Soil Bacterial Diversity and Potential Functions Are Regulated by Long-Term Conservation Tillage and Straw Mulching

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    Soil physiochemical properties are regulated by cropping practices, but little is known about how tillage influences soil microbial community diversity and functions. Here, we assessed soil bacterial community assembly and functional profiles in relation to tillage. Soils, collected in 2018 from a 17‐year field experiment in northwestern China, were analyzed using high‐throughput sequencing and the PICRUSt approach. The taxonomic diversity of bacterial communities was dominated primarily by the phyla Proteobacteria (32–56%), Bacteroidetes (12–33%), and Actinobacteria (17–27%). Alpha diversity (Chao1, Shannon, Simpson, and operational taxonomic unit (OTU) richness) was highest under no‐tillage with crop residue removed (NT). Crop residue retention on the soil surface (NTS) or incorporated into soil (TS) promoted the abundance of Proteobacteria by 16 to 74% as compared to conventional tillage (T). Tillage practices mainly affected the pathways of soil metabolism, genetic information processing, and environmental information processing. Soil organic C and NH4–N were the principal contributors to the diversity and composition of soil microbiota, whereas soil pH, total nitrogen, total P, and moisture had little effect. Our results suggest that long‐term conservation practices with no‐tillage and crop residue retention shape soil bacterial community composition through modifying soil physicochemical properties and promoting the metabolic function of soil microbiomes

    emiT: an apparatus to test time reversal invariance in polarized neutron decay

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    We describe an apparatus used to measure the triple-correlation term (\D \hat{\sigma}_n\cdot p_e\times p_\nu) in the beta-decay of polarized neutrons. The \D-coefficient is sensitive to possible violations of time reversal invariance. The detector has an octagonal symmetry that optimizes electron-proton coincidence rates and reduces systematic effects. A beam of longitudinally polarized cold neutrons passes through the detector chamber, where a small fraction beta-decay. The final-state protons are accelerated and focused onto arrays of cooled semiconductor diodes, while the coincident electrons are detected using panels of plastic scintillator. Details regarding the design and performance of the proton detectors, beta detectors and the electronics used in the data collection system are presented. The neutron beam characteristics, the spin-transport magnetic fields, and polarization measurements are also described.Comment: 15 pages, 13 figure

    Long-Term Nitrogen Fertilization Impacts on Soil Bacteria, Grain Yield and Nitrogen Use Efficiency of Wheat in Semiarid Loess Plateau, China

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    Soil bacteria are key components of the soil microbial community contributing to soil health. Nitrogen (N) fertilization is an important factor that affects soil microbial community and cereal production. This study aims to explore the impact of long-term N fertilization on soil bacterial diversity, nitrogen use efficiency (NUE), and the grain yield of wheat in the semiarid region of Loess Plateau, China. The field experiment was conducted from 2003 to 2018 including five N treatments: 0 (N0), 52.5 (N52.5), 105 (N105), 157.5 (N157.5), and 210 (N210) kg N h

    Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source

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    On 2017 August 17, the Laser Interferometer Gravitational-wave Observatory (LIGO) and the Virgo interferometer detected gravitational waves emanating from a binary neutron star merger, GW170817. Nearly simultaneously, the Fermi and INTEGRAL telescopes detected a gamma-ray transient, GRB 170817A. 10.9 hours after the gravitational wave trigger, we discovered a transient and fading optical source, Swope Supernova Survey 2017a (SSS17a), coincident with GW170817. SSS17a is located in NGC 4993, an S0 galaxy at a distance of 40 megaparsecs. The precise location of GW170817 provides an opportunity to probe the nature of these cataclysmic events by combining electromagnetic and gravitational-wave observations.Comment: 25 pages, 10 figures, 2 tables, published today in Scienc

    Novel Mouse Model for Analysis of Macrophage Function in Neuroblastoma

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    Background: Neuroblastoma is the third most common childhood cancer and accounts for 12% of cancer-associated deaths in children under the age of 15. Patients with high risk neuroblastoma have a poor 5-year survival rate of less than 50%. Neuroblastoma tumors treated with the histone deacetylase inhibitor (HDACi) vorinostat have increased infiltration of macrophages with upregulated immune cell-surface receptors. Neuroblastoma cells release VEGF and M-CSF, which may alter intratumoral macrophage populations. VEGF has also been implicated in alteration of amyloid precursor protein family processing. Our lab demonstrated that amyloid precursor protein 2 (APLP2), a member of the amyloid precursor protein family, plays an important role in the migration of tumor cells. APLP2 is known to be expressed by macrophages, but no studies have previously examined macrophage functions that are impacted by APLP2 in the context of neuroblastoma disease and its treatment by HDACi drugs. Significance of Problem: Because of the high morbidity and mortality associated with neuroblastoma, studies such as this one that are designed to comprehend the interaction of immunity and treatment in neuroblastoma are clinically significant. The results from this study are also expected to expand our comprehension of macrophage function and regulation, and thus will be of broad value in the immunology and oncology fields. Experimental Design and Results: We have treated neuroblastoma tumor cells in vitro with M344, an HDACi with structural similarity to vorinostat, and showed that M344 decreases neuroblastoma cell growth. In addition, we have generated mice that lack APLP2 expression in cells expressing the Csf-1 receptor (a protein characteristically expressed by macrophages and dendritic cells). We discovered that following polarization, macrophages collected from the bone marrow of these mice have an altered distribution of M1 and M2 sub-populations, which are macrophage sub-populations known to differ in their migratory capabilities. Furthermore, we have shown that M1 and M2 subpopulations of bone marrow-derived macrophages from normal mice differ in their expression of APLP2. Thus, APLP2 is influential in macrophage biology, and we have created a novel mouse model for defining its specific contributions in mice treated with HDACi that influence macrophage biology. Conclusions: Based on the data that we have acquired, we are well positioned to fully explore both the impact of HDACi drugs on macrophage/dendritic cell populations in a syngeneic neuroblastoma mouse model, and to define the role of APLP2 in the function of these cell populations in the context of neuroblastoma.https://digitalcommons.unmc.edu/chri_forum/1000/thumbnail.jp

    The Old Host-Galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational Wave Source

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    We present an analysis of the host-galaxy environment of Swope Supernova Survey 2017a (SSS17a), the discovery of an electromagnetic counterpart to a gravitational wave source, GW170817. SSS17a occurred 1.9 kpc (in projection; 10.2") from the nucleus of NGC 4993, an S0 galaxy at a distance of 40 Mpc. We present a Hubble Space Telescope (HST) pre-trigger image of NGC 4993, Magellan optical spectroscopy of the nucleus of NGC 4993 and the location of SSS17a, and broad-band UV through IR photometry of NGC 4993. The spectrum and broad-band spectral-energy distribution indicate that NGC 4993 has a stellar mass of log (M/M_solar) = 10.49^{+0.08}_{-0.20} and star formation rate of 0.003 M_solar/yr, and the progenitor system of SSS17a likely had an age of >2.8 Gyr. There is no counterpart at the position of SSS17a in the HST pre-trigger image, indicating that the progenitor system had an absolute magnitude M_V > -5.8 mag. We detect dust lanes extending out to almost the position of SSS17a and >100 likely globular clusters associated with NGC 4993. The offset of SSS17a is similar to many short gamma-ray burst offsets, and its progenitor system was likely bound to NGC 4993. The environment of SSS17a is consistent with an old progenitor system such as a binary neutron star system.Comment: ApJL in pres
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