151 research outputs found

    Association patterns and foraging behaviour in natural and artificial guppy shoals

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    Animal groups are often nonrandom assemblages of individuals that tend to be assorted by factors such as sex, body size, relatedness and familiarity. Laboratory studies using fish have shown that familiarity among shoal members confers a number of benefits to individuals, such as increased foraging success. However, it is unclear whether fish in natural shoals obtain these benefits through association with familiars. We investigated whether naturally occurring shoals of guppies, Poecilia reticulata, are more adept at learning a novel foraging task than artificial (in which we selected shoal members randomly) shoals. We used social network analysis to compare the structures of natural and artificial shoals and examined whether shoal organization predicts patterns of foraging behaviour. Fish in natural shoals benefited from increased success in the novel foraging task compared with fish in artificial shoals. Individuals in natural shoals showed a reduced latency to approach the novel feeder, followed more and formed smaller subgroups compared to artificial shoals. Our findings show that fish in natural shoals do gain foraging benefits and that this may be facilitated by a reduced perception of risk among familiarized individuals and/or enhanced social learning mediated by following other individuals and small group sizes. Although the structure of shoals was stable over time, we found no direct relationship between shoal social structure and patterns of foraging behaviour

    Changing Groundwater Levels in the Sandstone Aquifers of Northern Illinois and Southern Wisconsin: Impacts on Available Water Supply

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    In 2014-15, the Illinois State Water Survey conducted their largest synoptic measurement of water levels (i.e., heads) in Cambrian-Ordovician sandstone wells since 1980. The study covered 33 counties in the northern half of Illinois where demands for water are satisfied, in part, by sandstone aquifers. The Wisconsin Geological and Natural History Survey also measured sandstone wells in 10 counties in southern Wisconsin. These observations were used to generate head contours of the sandstone aquifers. These contours provide insight into the direction and magnitude of groundwater flow. They also can be compared with historic measurements, providing insight into the impact of changing groundwater withdrawals through time. In predevelopment conditions, heads in the Cambrian-Ordovician sandstone aquifers were near or above land surface. Due to pumping from the sandstone aquifers, heads have decreased over time; this decrease is referred to as drawdown. In 2014, drawdown in northeastern Illinois was typically over 300 ft and exceeded 800 ft in the Joliet region. Three factors drove this large drawdown. First, demands for water from sandstone aquifers are much greater in northeastern Illinois than in the rest of the study region. Second, the sandstone aquifers are overlain by aquitards, which are low permeable materials that limit vertical infiltration of water. Third, the Sandwich Fault Zone limits water flowing into the sandstone aquifers of northeastern Illinois from the south. Heads near the center of the cone of depression continue to have a decreasing trend. The more severe drawdown in northeastern Illinois has resulted in local areas where heads have fallen below the top of the sandstone, known as desaturation. Desaturation of a sandstone aquifer can create a number of water quality and quantity concerns. The uppermost sandstone, the St. Peter, was observed to be partially desaturated in portions of Will, Kane, and Kendall Counties under non-pumping conditions. Other areas in these counties are at risk of desaturation under pumping conditions or with the installation of additional wells connecting the St. Peter to deeper, more heavily stressed sandstones. Simulations from a groundwater flow model indicate that the risk of desaturation will increase with increased future withdrawals. Despite the relatively small demand for water throughout much of central Illinois, heads have been declining since predevelopment, likely due to the shale overlying the sandstone. This shale serves as an aquitard, minimizing vertical infiltration of groundwater to the sandstone. Sustained drawdown in this region could potentially induce flow from the southern half of the state, where water in the sandstone is highly saline and not suitable as a drinking water supply. Drawdown in northwestern Illinois was also typically small (<100 ft), primarily due to two factors: 1) low demands from the sandstone aquifers and 2) the absence of shale aquitards. The notable exception is in Winnebago County, near Rockford, where demands are historically high and drawdown was on the order of 100-200 ft. While the quantity of water in the aquifer is not a concern in this region, large withdrawals could result in reductions of natural groundwater discharge to surface waters, impacting stream ecosystems under low flow conditions. Drawdown since predevelopment was over 300 ft in southeastern Wisconsin, with the greatest drawdown in Waukesha County of over 400 ft. Recent trends indicate heads in the Waukesha area are recovering, although they are still well below predevelopment levels. [This report is also associated with the fact sheets: Changing Groundwater Levels in the Cambrian-Ordovician Sandstone Aquifers of Northern Illinois, 1980-2014, Groundwater Availability in Northeastern Illinois from Deep Sandstone Aquifers, and Sources of Water for Communities in Northeastern Illinois.published or submitted for publicationis peer reviewedOpe

    Science Impacts of the SPHEREx All-Sky Optical to Near-Infrared Spectral Survey: Report of a Community Workshop Examining Extragalactic, Galactic, Stellar and Planetary Science

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    SPHEREx is a proposed SMEX mission selected for Phase A. SPHEREx will carry out the first all-sky spectral survey and provide for every 6.2" pixel a spectra between 0.75 and 4.18 μ\mum [with R\sim41.4] and 4.18 and 5.00 μ\mum [with R\sim135]. The SPHEREx team has proposed three specific science investigations to be carried out with this unique data set: cosmic inflation, interstellar and circumstellar ices, and the extra-galactic background light. It is readily apparent, however, that many other questions in astrophysics and planetary sciences could be addressed with the SPHEREx data. The SPHEREx team convened a community workshop in February 2016, with the intent of enlisting the aid of a larger group of scientists in defining these questions. This paper summarizes the rich and varied menu of investigations that was laid out. It includes studies of the composition of main belt and Trojan/Greek asteroids; mapping the zodiacal light with unprecedented spatial and spectral resolution; identifying and studying very low-metallicity stars; improving stellar parameters in order to better characterize transiting exoplanets; studying aliphatic and aromatic carbon-bearing molecules in the interstellar medium; mapping star formation rates in nearby galaxies; determining the redshift of clusters of galaxies; identifying high redshift quasars over the full sky; and providing a NIR spectrum for most eROSITA X-ray sources. All of these investigations, and others not listed here, can be carried out with the nominal all-sky spectra to be produced by SPHEREx. In addition, the workshop defined enhanced data products and user tools which would facilitate some of these scientific studies. Finally, the workshop noted the high degrees of synergy between SPHEREx and a number of other current or forthcoming programs, including JWST, WFIRST, Euclid, GAIA, K2/Kepler, TESS, eROSITA and LSST.Comment: Report of the First SPHEREx Community Workshop, http://spherex.caltech.edu/Workshop.html , 84 pages, 28 figure

    The Vehicle, Fall 1983

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    Vol. 25, No. 1 Table of Contents Amish BoyDevon Flesorpage 3 SyllogismJ. Maura Davispage 3 Ten SecondsD.L. Lewispage 4 The Cedar ChestBridget M. Howepage 4 A Christmas With CarolSteve Longpage 5 TeethMichelle Mitchellpage 7 An I-Love-You PoemD.L. Lewispage 8 The Dragon SlayerSusan Gradypage 8 A DefinitionAmy J. Eadespage 9 FingernailsSuzanne Hornpage 10 The Liar\u27s TableBrook Wilsonpage 10 Fifi\u27s Last PartySteve Longpage 12 Absence/PresenceSuzanne Hornpage 13 From the Rantings of a Mad Astronomy StudentAmy J. Eadespage 13 In the Name of the Father, the Son, and MachiavelliF. Link Rapierpage 15 Errant LoverBecky Lawsonpage 16 DaddyKevin Lylespage 16 GhostsGary Ervinpage 17 TangoF. Link Rapierpage 17 Grandma\u27s SlippersBecky Lawsonpage 18 EdgesAmy J. Eadespage 19 Having ChildrenDevon Flesorpage 20 Young Black GirlKevin Lylespage 21 CatSuzanne Hornpage 22 Breakfast for OneMichelle Mitchellpage 22 A Modest ProposalBrooke Sanfordpage 23 Post MortemF. Link Rapierpage 26 Who Said I Forgot?Lynne Krausepage 27 The Corner Booth at StuckeysMaggie Kennedypage 28 The First DayDavis Brydenpage 29 DownLynne Krausepage 30 Fairie RingDevon Flesorpage 31 The LaundrymatKathy Fordpage 32 Sunday in OctoberBridget M. Howepage 32 The Kitchen WindowMaggie Kennedypage 33 UntitledChristina Maire Vitekpage 34 8th Grade Field Trip to SpringfieldMichelle Mitchellpage 34 Children of the FortiesF. Link Rapierpage 35 one winter and i was eightGary Ervinpage 35 Don\u27t we all know?Thomas B. Waltrippage 36 The TravelerMaggie Kennedypage 36 The VisitKathy Fordpage 40 CubismMaggie Kennedypage 40https://thekeep.eiu.edu/vehicle/1042/thumbnail.jp

    The Vehicle, Fall 1983

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    Vol. 25, No. 1 Table of Contents Amish BoyDevon Flesorpage 3 SyllogismJ. Maura Davispage 3 Ten SecondsD.L. Lewispage 4 The Cedar ChestBridget M. Howepage 4 A Christmas With CarolSteve Longpage 5 TeethMichelle Mitchellpage 7 An I-Love-You PoemD.L. Lewispage 8 The Dragon SlayerSusan Gradypage 8 A DefinitionAmy J. Eadespage 9 FingernailsSuzanne Hornpage 10 The Liar\u27s TableBrook Wilsonpage 10 Fifi\u27s Last PartySteve Longpage 12 Absence/PresenceSuzanne Hornpage 13 From the Rantings of a Mad Astronomy StudentAmy J. Eadespage 13 In the Name of the Father, the Son, and MachiavelliF. Link Rapierpage 15 Errant LoverBecky Lawsonpage 16 DaddyKevin Lylespage 16 GhostsGary Ervinpage 17 TangoF. Link Rapierpage 17 Grandma\u27s SlippersBecky Lawsonpage 18 EdgesAmy J. Eadespage 19 Having ChildrenDevon Flesorpage 20 Young Black GirlKevin Lylespage 21 CatSuzanne Hornpage 22 Breakfast for OneMichelle Mitchellpage 22 A Modest ProposalBrooke Sanfordpage 23 Post MortemF. Link Rapierpage 26 Who Said I Forgot?Lynne Krausepage 27 The Corner Booth at StuckeysMaggie Kennedypage 28 The First DayDavis Brydenpage 29 DownLynne Krausepage 30 Fairie RingDevon Flesorpage 31 The LaundrymatKathy Fordpage 32 Sunday in OctoberBridget M. Howepage 32 The Kitchen WindowMaggie Kennedypage 33 UntitledChristina Maire Vitekpage 34 8th Grade Field Trip to SpringfieldMichelle Mitchellpage 34 Children of the FortiesF. Link Rapierpage 35 one winter and i was eightGary Ervinpage 35 Don\u27t we all know?Thomas B. Waltrippage 36 The TravelerMaggie Kennedypage 36 The VisitKathy Fordpage 40 CubismMaggie Kennedypage 40https://thekeep.eiu.edu/vehicle/1042/thumbnail.jp

    Myoglobin‐mediated lipid shuttling increases adrenergic activation of brown and white adipocyte metabolism and is as a marker of thermogenic adipocytes in humans

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    Background: Recruitment and activation of brown adipose tissue (BAT) results in increased energy expenditure (EE) via thermogenesis and represents an intriguing therapeutic approach to combat obesity and treat associated diseases. Thermogenesis requires an increased and efficient supply of energy substrates and oxygen to the BAT. The hemoprotein myoglobin (MB) is primarily expressed in heart and skeletal muscle fibres, where it facilitates oxygen storage and flux to the mitochondria during exercise. In the last years, further contributions of MB have been assigned to the scavenging of reactive oxygen species (ROS), the regulation of cellular nitric oxide (NO) levels and also lipid binding. There is a substantial expression of MB in BAT, which is induced during brown adipocyte differentiation and BAT activation. This suggests MB as a previously unrecognized player in BAT contributing to thermogenesis. Methods and results: This study analyzed the consequences of MB expression in BAT on mitochondrial function and thermogenesis in vitro and in vivo. Using MB overexpressing, knockdown or knockout adipocytes, we show that expression levels of MB control brown adipocyte mitochondrial respiratory capacity and acute response to adrenergic stimulation, signalling and lipolysis. Overexpression in white adipocytes also increases their metabolic activity. Mutation of lipid interacting residues in MB abolished these beneficial effects of MB. In vivo, whole-body MB knockout resulted in impaired thermoregulation and cold- as well as drug-induced BAT activation in mice. In humans, MB is differentially expressed in subcutaneous (SC) and visceral (VIS) adipose tissue (AT) depots, differentially regulated by the state of obesity and higher expressed in AT samples that exhibit higher thermogenic potential. Conclusions: These data demonstrate for the first time a functional relevance of MBs lipid binding properties and establish MB as an important regulatory element of thermogenic capacity in brown and likely beige adipocytes. Keywords: energy expenditure; hemoprotein; metabolism; obesity; oxphos; uncoupling protein

    Measurement of Angular Distributions and R= sigma_L/sigma_T in Diffractive Electroproduction of rho^0 Mesons

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    Production and decay angular distributions were extracted from measurements of exclusive electroproduction of the rho^0(770) meson over a range in the virtual photon negative four-momentum squared 0.5< Q^2 <4 GeV^2 and the photon-nucleon invariant mass range 3.8< W <6.5 GeV. The experiment was performed with the HERMES spectrometer, using a longitudinally polarized positron beam and a ^3He gas target internal to the HERA e^{+-} storage ring. The event sample combines rho^0 mesons produced incoherently off individual nucleons and coherently off the nucleus as a whole. The distributions in one production angle and two angles describing the rho^0 -> pi+ pi- decay yielded measurements of eight elements of the spin-density matrix, including one that had not been measured before. The results are consistent with the dominance of helicity-conserving amplitudes and natural parity exchange. The improved precision achieved at 47 GeV, reveals evidence for an energy dependence in the ratio R of the longitudinal to transverse cross sections at constant Q^2.Comment: 15 pages, 15 embedded figures, LaTeX for SVJour(epj) document class Revision: Fig. 15 corrected, recent data added to Figs. 10,12,14,15; minor changes to tex

    Observation of a Coherence Length Effect in Exclusive Rho^0 Electroproduction

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    Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H, 3He, and 14N targets has been studied by the HERMES experiment at squared four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20 GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasing coherence length of quark-antiquark fluctuations of the virtual photon. The data provide clear evidence of the interaction of the quark- antiquark fluctuations with the nuclear medium.Comment: RevTeX, 5 pages, 3 figure

    Determination of the Deep Inelastic Contribution to the Generalised Gerasimov-Drell-Hearn Integral for the Proton and Neutron

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    The virtual photon absorption cross section differences [sigma_1/2-sigma_3/2] for the proton and neutron have been determined from measurements of polarised cross section asymmetries in deep inelastic scattering of 27.5 GeV longitudinally polarised positrons from polarised 1H and 3He internal gas targets. The data were collected in the region above the nucleon resonances in the kinematic range nu < 23.5 GeV and 0.8 GeV**2 < Q**2 < 12 GeV**2. For the proton the contribution to the generalised Gerasimov-Drell-Hearn integral was found to be substantial and must be included for an accurate determination of the full integral. Furthermore the data are consistent with a QCD next-to-leading order fit based on previous deep inelastic scattering data. Therefore higher twist effects do not appear significant.Comment: 6 pages, 3 figures, 1 table, revte
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