2,607 research outputs found

    Stream biasing by different induction sequences: Evaluating stream capture as an account of the segregation-promoting effects of constant-frequency inducers

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    Stream segregation for a test sequence comprising high-frequency (H) and low-frequency (L) pure tones, presented in a galloping rhythm, is much greater when preceded by a constant-frequency induction sequence matching one subset than by an inducer configured like the test sequence; this difference persists for several seconds. It has been proposed that constant-frequency inducers promote stream segregation by capturing the matching subset of test-sequence tones into an on-going, pre-established stream. This explanation was evaluated using 2-s induction sequences followed by longer test sequences (12–20 s). Listeners reported the number of streams heard throughout the test sequence. Experiment 1 used LHL– sequences and one or other subset of inducer tones was attenuated (0–24 dB in 6-dB steps, and 1). Greater attenuation usually caused a progressive increase in segregation, towards that following the constant-frequency inducer. Experiment 2 used HLH– sequences and the L inducer tones were raised or lowered in frequency relative to their test-sequence counterparts (DfIÂŒ 0, 0.5, 1.0, or 1.5 DfT). Either change greatly increased segregation. These results are concordant with the notion of attention switching to new sounds but contradict the stream-capture hypothesis, unless a “proto-object” corresponding to the continuing subset is assumed to form during the induction sequence

    Nitrogen and phosphorus loads to temperate seepage lakes associated with allochthonous dissolved organic carbon loads

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    Terrestrial loads of dissolved organic matter (DOM) have increased in recent years in many north temperate lakes. While much of the focus on the “browning” phenomena has been on its consequences for carbon cycling, much less is known about how it influences nutrient loading to lakes. We characterize potential loads of nitrogen and phosphorus to seepage lakes in northern Wisconsin, USA, based on a laboratory soil leaching experiment and a model that includes landscape cover and watershed area. In these seepage lakes, nutrient concentrations are positively correlated with dissolved organic carbon concentrations (nitrogen: r = 0.68, phosphorus: r = 0.54). Using long‐term records of browning, we found that dissolved organic matter‐associated nutrient loadings may have resulted in substantial increases in nitrogen and phosphorus in seepage lakes and could account for currently observed nutrient concentrations in the lake. “Silent” nutrient loadings to brown‐water lakes may lead to future water‐quality concerns. PLAIN LANGUAGE SUMMARY: The color of many temperate lakes is changing; some lakes are becoming more darkly stained brown. The tea‐colored stain is due to dissolved organic matter from the surrounding landscape. Much of the research related to the causes and consequences of increased staining, or “brownification,” relate to its connection to the carbon cycle. However, by examining long‐term lake chemical records, analyzing the properties of the organic compounds, and modeling potential flows of the compounds, we find that carbon is not the only element that is influenced by browning. Nitrogen and phosphorus, two nutrients important to growth of organisms at the base of the food web, may also be increasing in lakes due to brownification."Funding for this research was supported by the Northern Research Station and the Chequamegon-Nicolet National Forest (CNNF) of the United States Department of Agriculture (USDA) Forest Service and a National Science Foundation (NSF) grant to the University of Wisconsin-Madison to support the North Temperate Lakes Long-Term Ecological Research (NTLLTER) Site (DEB-#1440297)."https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL07721

    Correlation between Gamma-Ray bursts and Gravitational Waves

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    The cosmological origin of Îł\gamma-ray bursts (GRBs) is now commonly accepted and, according to several models for the central engine, GRB sources should also emit at the same time gravitational waves bursts (GWBs). We have performed two correlation searches between the data of the resonant gravitational wave detector AURIGA and GRB arrival times collected in the BATSE 4B catalog. No correlation was found and an upper limit \bbox{hRMS≀1.5×10−18h_{\text{RMS}} \leq 1.5 \times 10^{-18}} on the averaged amplitude of gravitational waves associated with Îł\gamma-ray bursts has been set for the first time.Comment: 7 pages, 3 figures, submitted to Phys. Rev.

    Depression, smoking abstinence and HPA function in women smokers

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    To determine whether smokers with a history of depression are differentially susceptible to smoking withdrawal, depressed mood induction and/or hypothalamic–pituitary–adrenal (HPA) axis dysregulation during smoking abstinence, 24 women smokers with and without such a history were studied. During one 5-day interval, participants smoked ad libitum ; during a second they abstained. On day 4, the participants were exposed to the Velten mood induction procedure (VMIP). Participants were then instructed to take 1 mg dexamethasone at 11 pm. At 4 pm on day 5, blood samples were withdrawn to determine the cortisol and ACTH response. Despite lower baseline cotinine levels, history-positive participants displayed more pronounced overall withdrawal distress than did history-negative participants, regardless of condition. The VMIP increased depression as well as negative responses on other profile of mood states subscales. Despite many overall group differences, no significant main effects for smoking condition nor interaction effects emerged. All participants evinced cortisol suppression in response to dexamethasone during both conditions, but the degree of suppression did not differ as a function of either abstinence or depression history. In history-positive smokers, however, ACTH levels trended toward overall elevation and showed almost no suppression during abstinence; thus exacerbation of HPA dysregulation in history-positive smokers during smoking abstinence cannot be ruled out. Copyright © 2004 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34962/1/623_ftp.pd

    The genetics of the Lp Antigen

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    Several genetic models were considered to explain the distribution of qualitatively positive and negative children in 204 Caucasian families. A model which best describes the inheritance of the Lp antigenic expression involves a major genetic locus which distinguishes two overlapping continuously distributed modes of quantitative activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66139/1/j.1469-1809.1974.tb01992.x.pd
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