365 research outputs found

    Some Effects of Photoperiod and Cold Storage on Oviposition of the Cereal Leaf Beetle Oulema Melanopus (Coleptera: Chrysomelidae)

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    An expanded program of research on the cereal leaf beetle, Oulema melanopus (L.), in various north-central states has made it necessary to develop methods of rearing all stages of the beetle for laboratory use. Because the insect survives diapause in the adult state (Castro, 1964 and Connin, et al., 1968) it must presently be stored 10-12 weeks at 38 F before consistent oviposition is obtained. Hoopingarner, et al. \u27(1965) indicated that, while males are sexually mature in the prediapause condition, the female was unwilling to mate until after diapause and was not mature sexually until after mating. More recent work by Bowers and Blickenstaff (1966) and Connin et al. (1967) indicated the possibility of breaking or eliminating diapause with chemicals. However, photoperiod also seemed influential in terminating diapause after varying periods of cold storage. The present paper reports observations on the photoperiodic effects

    Dynamic Docking Test System (DDTS) active table computer program NASA Advanced Docking System (NADS)

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    A computer program was developed to describe the three-dimensional motion of the Dynamic Docking Test System active table. The input consists of inertia and geometry data, actuator structural data, forcing function data, hydraulics data, servo electronics data, and integration control data. The output consists of table responses, actuator bending responses, and actuator responses

    Assessing Land Use Changes Due to Natural Gas Drilling Operations in the Marcellus Shale in Bradford County, PA

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    Extraction of natural gas from the Marcellus Shale formation began in the mid-2000s, and well pads and their associated infrastructure are now prominent fixtures throughout the Appalachian region. However, there is currently little research available to provide insight into its implications for land use and land cover change. In this case study of Bradford County, Pennsylvania, we used high-resolution aerial photography, land cover data, and well point data to quantify current and potential land use change as a result of gas drilling, as well as the types of land cover to be converted. Based on the number of permits held as of October 2011, we estimate that 276.84 hectares of primarily agricultural land have been cleared for well pads, access roads, and impoundment ponds in Bradford County. If all permitted wells are developed, we estimate between 620.60 and 3,983.50 hectares of additional land use change could occur

    Ferromagnetism or slow paramagnetic relaxation in Fe-doped Li3_3N?

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    We report on isothermal magnetization, M\"ossbauer spectroscopy, and magnetostriction as well as temperature-dependent alternating-current (ac) susceptibility, specific heat, and thermal expansion of single crystalline and polycrstalline Li2_2(Li1x_{1-x}Fex_x)N with x=0x = 0 and x0.30x \approx 0.30. Magnetic hysteresis emerges at temperatures below T50T \approx 50\,K with coercivity fields of up to μ0H=11.6\mu_0H = 11.6\,T at T=2T = 2\,K and magnetic anisotropy energies of 310310\,K (2727\,meV). The ac susceptibility is strongly frequency dependent (f=10f\,=\,10--10,00010,000\,Hz) and reveals an effective energy barrier for spin reversal of ΔE1100\Delta E \approx 1100\,K. The relaxation times follow Arrhenius behavior for T>25T > 25\,K. For T<10T < 10\,K, however, the relaxation times of τ1010\tau \approx 10^{10}\,s are only weakly temperature-dependent indicating the relevance of a quantum tunneling process instead of thermal excitations. The magnetic entropy amounts to more than 2525\,J molFe1^{-1}_{\rm Fe}\,K1^{-1} which significantly exceeds RRln2, the value expected for the entropy of a ground state doublet. Thermal expansion and magnetostriction indicate a weak magneto-elastic coupling in accordance with slow relaxation of the magnetization. The classification of Li2_2(Li1x_{1-x}Fex_x)N as ferromagnet is stressed and contrasted with highly anisotropic and slowly relaxing paramagnetic behavior.Comment: 12 pages, 10 figure

    Probing High Permeability of Nuclear Pore Complexes by Scanning Electrochemical Microscopy: Ca2+ Effects on Transport Barriers

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http:doi.org/10.1021/acs.analchem.9b00796.The nuclear pore complex (NPC) solely mediates molecular transport between the nucleus and cytoplasm of a eukaryotic cell to play important biological and biomedical roles. However, it is not well-understood chemically how this biological nanopore selectively and efficiently transports various substances, including small molecules, proteins, and RNAs by using transport barriers that are rich in highly disordered repeats of hydrophobic phenylalanine and glycine intermingled with charged amino acids. Herein, we employ scanning electrochemical microscopy to image and measure the high permeability of NPCs to small redox molecules. The effective medium theory demonstrates that the measured permeability is controlled by diffusional translocation of probe molecules through water-filled nanopores without steric or electrostatic hindrance from hydrophobic or charged regions of transport barriers, respectively. However, the permeability of NPCs is reduced by a low millimolar concentration of Ca2+, which can interact with anionic regions of transport barriers to alter their spatial distributions within the nanopore. We employ atomic force microscopy to confirm that transport barriers of NPCs are dominantly recessed (∼80%) or entangled (∼20%) at the high Ca2+ level in contrast to authentic populations of entangled (∼50%), recessed (∼25%), and “plugged” (∼25%) conformations at a physiological Ca2+ level of submicromolar. We propose a model for synchronized Ca2+ effects on the conformation and permeability of NPCs, where transport barriers are viscosified to lower permeability. Significantly, this result supports a hypothesis that the functional structure of transport barriers is maintained not only by their hydrophobic regions, but also by charged regions

    OXYGEN SENSOR WITH ADVANCED OXIDE ELECTRODE MATERIALS

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    Re-analysis of the Levanluhta skeletal material : Sex and stature estimation of individuals in an Iron Age water burial in Finland

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    Levanluhta, an Iron Age water burial site in Finland, and its material consisting of commingled skeletal remains and artifacts, has been studied by several researchers over the past 100 years, resulting in multiple interpretations of the people and the site. Previous skeletal analyses have concluded that the majority of the individuals represented in the remains were females and children and were of relatively short stature, so possibly nutritionally deprived. This study re-analyzed the commingled adult human remains with updated methods. The methods applied in this study to estimate sex and stature were based on more representative European reference samples than the previously applied methods. The methods included morphology, osteometrics, and computed tomography (CT) scans. Our results indicated that depending on the reference data, the majority of the individual adult bones including os coxae (73%, n = 45) and long bones (humerus 83%-89%, n = 52; radius 72%-89%, n = 47; ulna 50%-65%, n = 58; femur 92%-100%, n = 25; tibia 77%-85%, n = 26) were classified as females based on their size and morphology. The cross-sectional bone properties of humerii, femora, and tibiae visualized using CT scanning also supported these findings. However, the cranial morphology did not show as clear female-biased sex ratio as other methods (42% females, 33% males, 24% undetermined, n = 33). In females, the mean stature based on the tibia (155.3 cm, n = 10) was within the range of the coeval European females and did not necessarily indicate nutritional deprivation, which is in line with previously published stable isotope findings from the site. The mean stature based on the tibia suggested that the Levanluhta males were short (164.0 cm, n = 3), but final interpretations were limited due to the small number of male individuals. The current study affirmed that the Levanluhta skeletal assemblage was female biased and gave new insights into interpretation of the stature.Peer reviewe

    Influences on achieving motor milestones: A twin-singleton study

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    In order to determine if twinning impacted achievement of motor milestones the attainment of early motor milestones in twins was examined and compared to published data from singletons of the same age from the same culture and birth years. We examined the influence of twinning, sex, zygosity and birth cohort (1987-2001) on the motor development of twins aged 0 to 24 months. Data on the attainment of motor milestones (turn, sit, crawl, stand and walk) of twins were collected from maternal reports. All data were corrected for gestational age. Data from the twin sample were compared to normative data from singletons, which were available from Child Health Clinics (CHC). Analyses across twin data and the CHC singleton data revealed no differences between twins and singletons in achievement of motor milestones. Girls were able to sit without support slightly earlier than boys, otherwise there were no other sex differences. Birth-order analyses revealed minimal but significant differences in turning over from back to belly and for sitting without support between the first- and second-born. Dizygotic (DZ) twins were faster than monozygotic (MZ) twins in achieving the moment of sit, crawl, stand and walk. Twins born in earlier cohorts were faster in reaching the moment of crawl, sit and walk. It is concluded that there are no differences in time of reaching motor milestones between twins and singletons within the normal range. Sex has minimal to no effect on motor development in early childhood. DZ twins achieve motor milestones sooner than MZ twins. Attainment of gross motor milestones (crawl, stand and walk) is delayed in later birth cohorts
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