697 research outputs found

    LANDSAT D local user terminal study

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    The effect of the changes incorporated in the LANDSAT D system on the ability of a local user terminal to receive, record and process data in real time was studied. Alternate solutions to the problems raised by these changes were evaluated. A loading analysis was performed in order to determine the quantities of data that a local user terminal (LUT) would be interested in receiving and processing. The number of bits in an MSS and a TM scene were calculated along with the number of scenes per day that an LUT might require for processing. These then combined to a total number of processed bits/day for an LUT as a function of sensor and coverage circle radius

    Investigations on the Peach 4 Debrite, a Late Pleistocene Mass Movement on the Northwest British Continental Margin

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    The Peach 4 debrite is the most recent in a series of large scale Pleistocene MTDs within the Barra fan on the northwest British continental margin. Geophysical data indicate that Peach 4 was formed through a combination of blocky and muddy debris flows and affects an area of ~ 700 km2. BGS core sample 56 -10 36, located directly over the Peach 4 debrite, provides a minimum age of 14.68 ka cal BP for the last major failure. An upwards fining turbidite sequence in BGS core sample 56 -10 239 is associ-ated with increased As and S concentrations, indicators of diagenetic pyrite which forms under anoxic conditions. It is proposed that As and S concentrations may pro-vide a method of distinguishing between contourite and turbidite sedimentation, though further research is required

    Rhenium elemental and isotopic variations at magmatic temperatures

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    This work was funded by Natural Environment Research Council UK Standard Grant to RGH, AJD, and JP (NE/T001119).Recent analytical advances in the measurement of rhenium (Re) isotope ratios allow its potential as a palaeoredox and chemical weathering proxy to be explored. However, a successful isotopic proxy must be grounded by an understanding of its composition and behaviour in the solid Earth. Here, we present Re concentrations and Re isotopic (δ187Re) compositions for a well-characterised sequence of lavas from Hekla volcano, Iceland. The concentration of Re varies from 0.02 to 1.4 ng/g, decreasing from basalt to more evolved lavas. We show that the crystallisation and removal of magnetite is responsible for the Re decrease in this system. By contrast, δ187Re values for the same suite of samples show a relatively narrow range (−0.45 to −0.22 0/1000), suggesting minimal resolvable Re isotope fractionation between magnetite and the silicate melt. Together with other samples, including mid-ocean ridge basalts, these first igneous data can be used to estimate a baseline for terrestrial materials (δ187Re = −0.33 ± 0.15 0/1000, 2 s.d., n = 14), from which low-temperature Re isotope variations in Earth’s surficial environments can be assessed, alongside the global isotope mass balance of Re.Peer reviewe

    Selfsimilar solutions in a sector for a quasilinear parabolic equation

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    We study a two-point free boundary problem in a sector for a quasilinear parabolic equation. The boundary conditions are assumed to be spatially and temporally "self-similar" in a special way. We prove the existence, uniqueness and asymptotic stability of an expanding solution which is self-similar at discrete times. We also study the existence and uniqueness of a shrinking solution which is self-similar at discrete times.Comment: 23 page

    A study of wrist-worn activity measurement as a potential real-world biomarker for late-life depression.

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    BACKGROUND: Late-life depression (LLD) is associated with a decline in physical activity. Typically this is assessed by self-report questionnaires and, more recently, with actigraphy. We sought to explore the utility of a bespoke activity monitor to characterize activity profiles in LLD more precisely. METHOD: The activity monitor was worn for 7 days by 29 adults with LLD and 30 healthy controls. Subjects underwent neuropsychological assessment and quality of life (QoL) (36-item Short-Form Health Survey) and activities of daily living (ADL) scales (Instrumental Activities of Daily Living Scale) were administered. RESULTS: Physical activity was significantly reduced in LLD compared with controls (t = 3.63, p < 0.001), primarily in the morning. LLD subjects showed slower fine motor movements (t = 3.49, p < 0.001). In LLD patients, activity reductions were related to reduced ADL (r = 0.61, p < 0.001), lower QoL (r = 0.65, p < 0.001), associative learning (r = 0.40, p = 0.036), and higher Montgomery-Ã…sberg Depression Rating Scale score (r = -0.37, p < 0.05). CONCLUSIONS: Patients with LLD had a significant reduction in general physical activity compared with healthy controls. Assessment of specific activity parameters further revealed the correlates of impairments associated with LLD. Our study suggests that novel wearable technology has the potential to provide an objective way of monitoring real-world function.This study was funded by an award from the UK Medical Research Council (G1001828/1)

    Specific isoforms of actin-binding proteins on distinct populations of Golgi-derived vesicles

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    Golgi membranes and Golgi-derived vesicles are associated with multiple cytoskeletal proteins and motors, the diversity and distribution of which have not yet been defined. Carrier vesicles were separated from Golgi membranes, using an in vitro budding assay, and different populations of vesicles were separated using sucrose density gradients. Three main populations of vesicles labeled with beta-COP, gamma-adaptin, or p200/myosin II were separated and analyzed for the presence of actin/actin-binding proteins, beta-Actin was bound to Golgi cisternae and to all populations of newly budded vesicles. Centractin was selectively associated with vesicles co-distributing with beta-COP-vesicles, while p200/myosin II (non-muscle myosin IIA) and non-muscle myosin IIB were found on different vesicle populations. Isoforms of the Tm5 tropomyosins were found on selected Golgi-derived vesicles, while other Tm isoforms did not colocalize with Tm5 indicating the association of specialized actin filaments with Golgi-derived vesicles. Golgi-derived vesicles were shown to bind to F-actin polymerized from cytosol with Jasplakinolide. Thus, newly budded, coated vesicles derived from Golgi membranes can bind to actin and are customized for differential interactions with microfilaments by the presence of selective arrays of actin-binding proteins

    Social Complexity and Nesting Habits Are Factors in the Evolution of Antimicrobial Defences in Wasps

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    Microbial diseases are important selective agents in social insects and one major defense mechanism is the secretion of cuticular antimicrobial compounds. We hypothesized that given differences in group size, social complexity, and nest type the secretions of these antimicrobials will be under different selective pressures. To test this we extracted secretions from nine wasp species of varying social complexity and nesting habits and assayed their antimicrobial compounds against cultures of Staphylococcus aureus. These data were then combined with phylogenetic data to provide an evolutionary context. Social species showed significantly higher (18x) antimicrobial activity than solitary species and species with paper nests showed significantly higher (11x) antimicrobial activity than those which excavated burrows. Mud-nest species showed no antimicrobial activity. Solitary, burrow-provisioning wasps diverged at more basal nodes of the phylogenetic trees, while social wasps diverged from the most recent nodes. These data suggest that antimicrobial defences may have evolved in response to ground-dwelling pathogens but the most important variable leading to increased antimicrobial strength was increase in group size and social complexity

    EGF induces macropinocytosis and SNX1-modulated recycling of E-cadherin

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    In epithelia, junction proteins are endocytosed for modulation of cell-cell adhesion and cell polarity. In response to growth factors, the cell-cell adhesion protein E-cadherin is internalized from the cell surface with degradation or recycling as potential fates. However, the cellular machinery involved in cadherin internalization and recycling remains controversial. Here we investigated EGF-induced E-cadherin internalization. EGF stimulation of MCF-7 cells resulted in Rac1-modulated macropinocytosis of the E-cadherin-catenin-complex into endosomal compartments that colocalized with EEA1 and the sorting nexin, SNX1. Depletion of cellular SNX1 levels by siRNA resulted in increased intracellular accumulation and turnover of E-cadherin internalized from the cell surface in response to EGF. Moreover, SNX1 was also required for efficient recycling of internalized E-cadherin and re-establishment of epithelial adhesion. Together, these findings demonstrate a role for SNX1 in retrieval of E-cadherin from a degradative endosomal pathway and in membrane trafficking pathways that regulate E-cadherin recycling

    Trends in weight gain recorded in English primary care before and during the Coronavirus-19 pandemic: An observational cohort study using the OpenSAFELY platform.

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    BACKGROUND: Obesity and rapid weight gain are established risk factors for noncommunicable diseases and have emerged as independent risk factors for severe disease following Coronavirus Disease 2019 (COVID-19) infection. Restrictions imposed to reduce COVID-19 transmission resulted in profound societal changes that impacted many health behaviours, including physical activity and nutrition, associated with rate of weight gain. We investigated which clinical and sociodemographic characteristics were associated with rapid weight gain and the greatest acceleration in rate of weight gain during the pandemic among adults registered with an English National Health Service (NHS) general practitioner (GP) during the COVID-19 pandemic. METHODS AND FINDINGS: With the approval of NHS England, we used the OpenSAFELY platform inside TPP to conduct an observational cohort study of routinely collected electronic healthcare records. We investigated changes in body mass index (BMI) values recorded in English primary care between March 2015 and March 2022. We extracted data on 17,742,365 adults aged 18 to 90 years old (50.1% female, 76.1% white British) registered with an English primary care practice. We estimated individual rates of weight gain before (δ-prepandemic) and during (δ-pandemic) the pandemic and identified individuals with rapid weight gain (>0.5 kg/m2/year) in each period. We also estimated the change in rate of weight gain between the prepandemic and pandemic period (δ-change = δ-pandemic-δ-prepandemic) and defined extreme accelerators as the 10% of individuals with the greatest increase in their rate of weight gain (δ-change ≥1.84 kg/m2/year) between these periods. We estimated associations with these outcomes using multivariable logistic regression adjusted for age, sex, index of multiple deprivation (IMD), and ethnicity. P-values were generated in regression models. The median BMI of our study population was 27.8 kg/m2, interquartile range (IQR) [24.3, 32.1] in 2019 (March 2019 to February 2020) and 28.0 kg/m2, IQR [24.4, 32.6] in 2021. Rapid pandemic weight gain was associated with sex, age, and IMD. Male sex (male versus female: adjusted odds ratio (aOR) 0.76, 95% confidence interval (95% CI) [0.76, 0.76], p < 0.001), older age (e.g., 50 to 59 years versus 18 to 29 years: aOR 0.60, 95% CI [0.60, 0.61], p < 0.001]); and living in less deprived areas (least-deprived-IMD-quintile versus most-deprived: aOR 0.77, 95% CI [0.77, 0.78] p < 0.001) reduced the odds of rapid weight gain. Compared to white British individuals, all other ethnicities had lower odds of rapid pandemic weight gain (e.g., Indian versus white British: aOR 0.69, 95% CI [0.68, 0.70], p < 0.001). Long-term conditions (LTCs) increased the odds, with mental health conditions having the greatest effect (e.g., depression (aOR 1.18, 95% CI [1.17, 1.18], p < 0.001)). Similar characteristics increased odds of extreme acceleration in the rate of weight gain between the prepandemic and pandemic periods. However, changes in healthcare activity during the pandemic may have introduced new bias to the data. CONCLUSIONS: We found female sex, younger age, deprivation, white British ethnicity, and mental health conditions were associated with rapid pandemic weight gain and extreme acceleration in rate of weight gain between the prepandemic and pandemic periods. Our findings highlight the need to incorporate sociodemographic, physical, and mental health characteristics when formulating research, policies, and interventions targeting BMI in the period of post pandemic service restoration and in future pandemic planning
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