2,695 research outputs found

    A Preliminary Note on Egg Production from Milk-Fed Mosquitoes

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    Author Institution: Department of Zoology and Entomology, The Ohio State University, Columbus 1

    Survey of Terrestrial Invertebrate Species from Byers Cave; Dade County, Georgia

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    Byers Cave is one of Georgia’s largest cave systems and is inhabited by a wide variety of unique invertebrate organisms that have not been documented or studied. From March 2008 through April 2010, baited ramp pit-fall traps and visual surveys were used to sample and document invertebrate species that live in this cave system. After three trapping periods and four visual surveys, we collected over 4,400 individuals comprising 13 orders, 29 families and 34 species. The majority of these species were troglophiles and trogloxenes; however, there were also numerous troglobitic species present

    Ferromagnetic resonance in periodic particle arrays

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    We report measurements of the ferromagnetic resonance (FMR) spectra of arrays of submicron size periodic particle arrays of permalloy produced by electron-beam lithography. In contrast to plane ferromagnetic films, the spectra of the arrays show a number of additional resonance peaks, whose position depends strongly on the orientation of the external magnetic field and the interparticle interaction. Time-dependent micromagnetic simulation of the ac response show that these peaks are associated with coupled exchange and dipolar spin wave modesComment: 4 pages, 4 figure

    A Preliminary Note on Some Nutritional Requirements for Reproduction in Female Aedes Aegypti

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    Author Institution: Department of Zoology and Entomology, The Ohio State University, Columbus 1

    Multi-specimen and multi-site calibration of Aleutian coralline algal Mg/Ca to sea surface temperature

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    Higher latitude oceanic and climatic reconstructions are needed to distinguish natural climate variability from anthropogenic warming in regions projected to experience significant increases in temperature during this century. Clathromorphum nereostra turn is a long-lived coralline alga abundant along the Aleutian archipelago that records seasonal to centennial fluctuations in seawater temperatures in its high-Mg calcite skeleton. Thus, C. nereostratum is an important proxy archive to reconstruct past seawater temperature variability in this data-poor subarctic region. Here, we measured magnesium to calcium ratios (Mg/Ca) by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) along the growth axis in six live-collected specimens from three islands in the Aleutian archipelago to assess Mg/Ca reproducibility and to calibrate algal Mg/Ca against modern gridded sea surface temperature (SST) data products. The master Mg/Ca SST transfer function, determined by averaging the algal Mg/Ca SST from each island (n = 6), resulted in a reconstruction error of +/-0.45 degrees C, a 31-46% reduction in error compared to the reconstruction error for a single alga. The master algal-SST record interpolated to monthly and annual resolution significantly varied with gridded SST data products (r(2) = 0.98, p < 0.0001, n = 517 and r(2) = .27, p < 0.0003, n = 44, respectively) for the period from 1960 to 2003. Therefore, coralline algal Mg/Ca-derived SST reconstructions record absolute changes in past SST variability in the Aleutian archipelago. The transfer functions developed here can be applied to Mg/Ca records generated from long-lived specimens of C. nereostra turn to reconstruct northern North Pacific and Bering Sea SST variability for the past several hundred years

    Magnetic Response of Aperiodic Wire Networks Based on Fibonacci Distortions of Square Antidot Lattices

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    The static and dynamic magnetic responses of patterned ferromagnetic thin films are uniquely altered in the case of aperiodic patterns that retain long-range order (e.g., quasicrystals). We have fabricated permalloy wire networks based on periodic square antidot lattices (ADLs) distorted according to an aperiodic Fibonacci sequence applied to two lattice translations, d1  = 1618 nm and d2  = 1000 nm. The wire segment thickness is fixed at t = 25 nm, and the width W varies from 80 to 510 nm. We measured the DC magnetization between room temperature and 5 K. Room-temperature, narrow-band (9.7 GHz) ferromagnetic resonance (FMR) spectra were acquired for various directions of applied magnetic field. The DC magnetization curves exhibited pronounced step anomalies and plateaus that signal flux closure states. Although the Fibonacci distortion breaks the fourfold symmetry of a finite periodic square ADL, the FMR data exhibit fourfold rotational symmetry with respect to the applied DC magnetic field direction

    Fishing regulations, sexual dimorphism, and the life history of harvest

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    Freshwater recreational fisheries regulations are a vital tool for achieving social and ecological fisheries objectives. However, angler behavior and fish biology may interact to influence regulation efficacy in unexpected ways. We combined models of fish growth and angler behavior to explore how angler behavior interacts with fish life history to shape the probability of fish harvest given capture across ages, life stages, and sexes of walleye (Sander vitreus). Compared to females, males grew more quickly as juveniles, matured earlier, and reached smaller maximum sizes. Male walleye were therefore vulnerable to harvest for more of their reproductive lives than females because males spent more time at sizes where anglers were very likely to harvest them. We suggest that restricting harvest of large individuals in sexually dimorphic species may favor the survival of large, reproductive-aged females. Moreover, we show that combining models of fish growth and harvester behavior can provide insights into how harvest affects fish with complex life histories over the course of their lives. La réglementation relative aux pêches sportives en eau douce constitue un outil d’importance capitale pour l’atteinte des objectifs sociaux et écologiques des pêches. Les interactions des comportements des pêcheurs et de la biologie des poissons peuvent toutefois influencer l’efficacité de la réglementation de manière imprévue. Nous combinons des modèles de croissance des poissons et de comportement des pêcheurs afin d’examiner l’effet de l’interaction du comportement des pêcheurs et du cycle biologique des poissons sur la probabilité de récolte de poissons au vu des prises selon l’âge, de l’étape du cycle de vie et du sexe de dorés jaunes (Sander vitreus). Comparativement aux femelles, les mâles croissent plus vite quand ils sont juvéniles, arrivent à maturité plus tôt et atteignent des tailles maximums plus petites. Les dorés mâles sont donc plus vulnérables à la récolte pour une plus grande partie de leur vie reproductive que les femelles parce qu’ils passent plus de temps à des tailles qui les rendent plus susceptibles d’être récoltés par les pêcheurs. Nous suggérons que le fait de restreindre la récolte aux grands individus pour des espèces qui présentent un dimorphisme sexuel pourrait favoriser la survie des grandes femelles en âge de reproduction. Nous démontrons en outre que le jumelage de modèles de croissance des poissons et de comportement des pêcheurs peut fournir de l’information utile sur l’effet de la récolte sur les poissons aux cycles biologiques complexes au fil de leur vie

    Using the Bootstrap to test for symmetry under unknown dependence

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    This paper considers tests for symmetry of the one-dimensional marginal distribution of fractionally integrated processes. The tests are implemented by using an autoregressive sieve bootstrap approximation to the null sampling distribution of the relevant test statistics. The sieve bootstrap allows inference on symmetry to be carried out without knowledge of either the memory parameter of the data or of the appropriate norming factor for the test statistic and its asymptotic distribution. The small-sample properties of the proposed method are examined by means of Monte Carlo experiments, and applications to real-world data are also presented

    The combined effects of reactant kinetics and enzyme stability explain the temperature dependence of metabolic rates

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    A mechanistic understanding of the response of metabolic rate to temperature is essential for understanding thermal ecology and metabolic adaptation. Although the Arrhenius equation has been used to describe the effects of temperature on reaction rates and metabolic traits, it does not adequately describe two aspects of the thermal performance curve (TPC) for metabolic rate—that metabolic rate is a unimodal function of temperature often with maximal values in the biologically relevant temperature range and that activation energies are temperature dependent. We show that the temperature dependence of metabolic rate in ectotherms is well described by an enzyme-assisted Arrhenius (EAAR) model that accounts for the temperature-dependent contribution of enzymes to decreasing the activation energy required for reactions to occur. The model is mechanistically derived using the thermodynamic rules that govern protein stability. We contrast our model with other unimodal functions that also can be used to describe the temperature dependence of metabolic rate to show how the EAAR model provides an important advance over previous work. We fit the EAAR model to metabolic rate data for a variety of taxa to demonstrate the model’s utility in describing metabolic rate TPCs while revealing significant differences in thermodynamic properties across species and acclimation temperatures. Our model advances our ability to understand the metabolic and ecological consequences of increases in the mean and variance of temperature associated with global climate change. In addition, the model suggests avenues by which organisms can acclimate and adapt to changing thermal environments. Furthermore, the parameters in the EAAR model generate links between organismal level performance and underlying molecular processes that can be tested for in future work
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