20,146 research outputs found

    Testing of Great Bay Oysters for Two Protozoan Pathogens

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    Two protozoan pathogens, Haplosporidium nelsoni (MSX) and Perkinsus marinus (Dermo) are known to be present in Great Bay oysters. With funds provided by the Piscataqua Region Estuaries Partnership (PREP), the Marine Fisheries Division of the New Hampshire Fish and Game Department (NHF&G) continues to assess the presence and intensity of both of these disease conditions in oysters from the major natural beds within the Great Bay estuarine system and at selected aquaculture sites. Histological examinations of Great Bay oysters have also revealed other endoparasites

    Financial innovation and the Great Moderation: what do household data say?

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    Aggressive deregulation of the household debt market in the early 1980s triggered innovations that greatly reduced the required home equity of U.S. households, allowing them to cash-out a large part of accumulated equity. In 1982, home equity equaled 71 percent of GDP; so this generated a borrowing shock of huge macroeconomic proportions. The combination of increasing household debt from 43 to 56 percent of GDP with high interest rates during the 1982-1990 period is consistent with such a shock to households’ demand for funds. This paper uses a quantitative general equilibrium model of lending from the wealthy to the middle class to evaluate the positive and normative aspects of the transition to a high debt economy. Using the model, we interpret evidence on the changing distribution of assets and debt as well as macro time series since 1982.Households - Economic aspects

    Pulsed Generic Advertising: The Case of Common Property

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    Regulation of fisheries production together with public promotion of fisheries products offer a potentially profitable environment for fishermen. Yet production restrictions are usually insufficient to prevent entry, causing depletion of the resource base and dissipation of long-run profits from promotion. Shorter run gains may be possible, providing producer response to advertising is not instantaneous. Lagged biological and economic responses appear to provide a rationale for pulsed advertising. Moreover, a pulsed advertising policy is shown to mitigate the adverse effects on the resource base which would normally accompany expansion of consumption without direct production control.generic promotion, oysters, common property, pulsed advertising, Environmental Economics and Policy, Resource /Energy Economics and Policy,

    Introgressive Hybridization and the Evolution of Lake-Adapted Catostomid Fishes.

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    Hybridization has been identified as a significant factor in the evolution of plants as groups of interbreeding species retain their phenotypic integrity despite gene exchange among forms. Recent studies have identified similar interactions in animals; however, the role of hybridization in the evolution of animals has been contested. Here we examine patterns of gene flow among four species of catostomid fishes from the Klamath and Rogue rivers using molecular and morphological traits. Catostomus rimiculus from the Rogue and Klamath basins represent a monophyletic group for nuclear and morphological traits; however, the Klamath form shares mtDNA lineages with other Klamath Basin species (C. snyderi, Chasmistes brevirostris, Deltistes luxatus). Within other Klamath Basin taxa, D. luxatus was largely fixed for alternate nuclear alleles relative to C. rimiculus, while Ch. brevirostris and C. snyderi exhibited a mixture of these alleles. Deltistes luxatus was the only Klamath Basin species that exhibited consistent covariation of nuclear and mitochondrial traits and was the primary source of mismatched mtDNA in Ch. brevirostris and C. snyderi, suggesting asymmetrical introgression into the latter species. In Upper Klamath Lake, D. luxatus spawning was more likely to overlap spatially and temporally with C. snyderi and Ch. brevirostris than either of those two with each other. The latter two species could not be distinguished with any molecular markers but were morphologically diagnosable in Upper Klamath Lake, where they were largely spatially and temporally segregated during spawning. We examine parallel evolution and syngameon hypotheses and conclude that observed patterns are most easily explained by introgressive hybridization among Klamath Basin catostomids

    Comparing Fixed-amount and Progressive-amount DRO Schedules for Tic Suppression in Youth with Chronic Tic Disorders

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    Chronic tic disorders (CTDs) involve motor and/or vocal tics that often cause substantial distress and impairment. Differential reinforcement of other behavior (DRO) schedules of reinforcement produce robust, but incomplete, reductions in tic frequency in youth with CTDs; however, a more robust reduction may be needed to affect durable clinical change. Standard, fixed‐amount DRO schedules have not commonly yielded such reductions, so we evaluated a novel, progressive‐amount DRO schedule, based on its ability to facilitate sustained abstinence from functionally similar behaviors. Five youth with CTDs were exposed to periods of baseline, fixed‐amount DRO (DRO‐F), and progressive‐amount DRO (DRO‐P). Both DRO schedules produced decreases in tic rate and increases in intertic interval duration, but no systematic differences were seen between the two schedules on any dimension of tic occurrence. The DRO‐F schedule was generally preferred to the DRO‐P schedule. Possible procedural improvements and other future directions are discussed

    Amygdala reactivity predicts adolescent antisocial behavior but not callous-unemotional traits.

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    Recent neuroimaging studies have suggested divergent relationships between antisocial behavior (AB) and callous-unemotional (CU) traits and amygdala reactivity to fearful and angry facial expressions in adolescents. However, little work has examined if these findings extend to dimensional measures of behavior in ethnically diverse, non-clinical samples, or if participant sex, ethnicity, pubertal stage, and age moderate associations. We examined links between amygdala reactivity and dimensions of AB and CU traits in 220 Hispanic and non-Hispanic Caucasian adolescents (age 11-15; 49.5% female; 38.2% Hispanic), half of whom had a family history for depression and thus were at relatively elevated risk for late starting, emotionally dysregulated AB. We found that AB was significantly related to increased right amygdala reactivity to angry facial expressions independent of sex, ethnicity, pubertal stage, age, and familial risk status for depression. CU traits were not related to fear- or anger-related amygdala reactivity. The present study further demonstrates that AB is related to increased amygdala reactivity to interpersonal threat cues in adolescents, and that this relationship generalizes across sex, ethnicity, pubertal stage, age, and familial risk status for depression
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