420 research outputs found

    A league of their own: demographics, motivations and patterns of use of 1,955 male adult non-medical anabolic steroid users in the United States

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    Background: Rule violations among elite-level sports competitors and tragedies among adolescents have largely defined the issue of non-medical anabolic-androgenic steroid (NMAAS) use for the public and policy makers. However, the predominant and oft-ignored segment of the NMAAS community exists in the general population that is neither participating in competitive sports nor adolescent. A clearer profile of NMAAS users within the general population is an initial step in developing a full understanding of NMAAS use and devising appropriate policy and interventions. This survey sought to provide a more comprehensive profile of NMAAS users by accessing a large sample of user respondents from around the United States. Methods: U.S.-based male NMAAS users (n = 1955) were recruited from various Internet websites dedicated to resistance training activities and use of ergogenic substances, mass emails, and print media to participate in a 291-item web-based survey. The Internet was utilized to provide a large and geographically diverse sample with the greatest degree of anonymity to facilitate participation. Results: The majority of respondents did not initiate AAS use during adolescence and their NMAAS use was not motivated by athletics. The typical user was a Caucasian, highly-educated, gainfully employed professional approximately 30 years of age, who was earning an above-average income, was not active in organized sports, and whose use was motivated by increases in skeletal muscle mass, strength, and physical attractiveness. These findings question commonly held views of the typical NMAAS user and the associated underlying motivations. Conclusion: The focus on cheating athletes and at risk youth has led to ineffective policy as it relates to the predominant group of NMAAS users. Effective policy, prevention or intervention should address the target population(s) and their reasons for use while utilizing their desire for responsible use and education

    The Venerable Converter: A New Approach to Power Processing

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    A regulating dc-to-dc converter is described which utilizes a new circuit configuration to achieve several desirable features including higher efficiency, a single circuit for regulation and conversion, minimized output filter requirements, and simplified control system applications. The dc operating characteristics are derived and the efficiency of the new converter is shown to compare favorably with the conventional boost regulator. An ac model is derived and a comparison is made between analytical and experimental results

    Do statins delay onset or slow progression of Alzheimer's dementia?

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    Statins (coenzyme-A reductase inhibitors) should not be used with the single intent to delay the onset or slow the progression of dementia. Large randomized control trials (RCTs) found that the administration of a statin had no significant effect on preventing or slowing all-cause cognitive decline (strength of recommendation [SOR]: A, based on large RCTs with narrow confidence interval). Specifically, there is insufficient evidence that statins delay the onset or slow the progression of Alzheimer's dementia (SOR: B, based on systematic review with heterogeneity). While 3 epidemiologic studies have found a decreased incidence of dementia among those taking statins, these studies have significant methodological shortcomings and do not show a causal relationship (SOR: C, based on poor-quality studies)

    The Venerable Converter: A New Approach to Power Processing

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    Effect of Insecticides and Plutella xylostella (Lepidoptera: Plutellidae) Genotype on a Predator and Parasitoid and Implications for the Evolution of Insecticide Resistance

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    In the laboratory and in cages in the greenhouse, we evaluated the toxicity of two insecticides (lambda-cyhalothrin and spinosad) on the parasitoid, Diadegma insulare (Cresson), and the predator, Coleomegilla maculate (DeGeer), both natural enemies of the diamondback moth, Plutella xylostella (L.). Lambda-cyhalothrin was very toxic to both natural enemies. Spinosad was less toxic to C. maculata adults and larvae, and slightly toxic to D. insulare. Both natural enemies suppressed P. xylostella populations in cages with 80% spinosad-treated and 20% nontreated plants; such suppression was not seen when lambda-cyhalothrin was used. Using broccoli, Brassica oleracea L. variety italica, a common host for P. xylostella, we also studied direct and indirect effects of both natural enemies in the presence and absence of the two insecticides and to different P. xylostella genotypes: resistant to the insecticide, susceptible, or heterozygous. Neither natural enemy could distinguish host genotype if P. xylostella were feeding on nontreated plants. They could also not distinguish between larvae feeding on spinosad-treated plants and nontreated plants, but D. insulare could distinguish between larvae feeding on lambda-cyhalothrin treated and nontreated plants. Our studies suggest that lambda-cyhalothrin has direct toxicity to these two natural enemies, can affect their host foraging and acceptance of P. xylostella and consequently would not be compatible in conserving these natural enemies in a program for suppression of P. xylostella. In contrast, our studies suggest that treatment with spinosad has much less effect on these natural enemies and would allow them to help suppress populations of P. xylostella. These findings are discussed in relation to the evolution of insecticide resistance and suppression of the pest population

    Effect of Bt Broccoli or Plants Treated With Insecticides on Ovipositional Preference and Larval Survival of Plutella xylostella (Lepidoptera: Plutellidae)

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    The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), a major pest of cruciferous crops throughout the world, has demonstrated an ability to develop resistance to many different classes of insecticides, including proteins from Bacillus thuringiensis that are expressed in plants (Bt plants). The ovipositional preferences and larval survival of strains (resistant strain, RR; heterozygous strain, RS; susceptible strain, SS) of P. xylostella to Cry1Ac-expressing broccoli or broccoli plants treated with lambda-cyhalothrin or spinosad were studied under greenhouse condition. Numbers of eggs per plant did not differ between Bt broccoli and non-Bt broccoli for Bt-RR, Bt-RS, and Bt-SS adults. Ovipositing adults (spinosad-RR, spinosad-RS, and spinosad-SS) also could not discriminate between spinosad-treated and untreated plants, and oviposition did not increase over the 13 d after spinosad treatment. For broccoli treated with lambda-cyhalothrin at the diagnostic dose of 20 ppm, all three insect strains (lc-RR, lc-RS, and lc-SS) had constant oviposition over time based on linear regressions. At the field dose of 80 ppm, the lc-RR strain had constant oviposition over time. The lc-SS susceptible strain had increasing oviposition over time, but the oviposition pattern on the nonsprayed broccoli also increased over time. Susceptible females layed fewer eggs on plants sprayed with lambda-cyhalothrin than on unsprayed plants. A residue-persistence test showed that spinosad and lambda-cyhalothrin could effectively control SS P. xylostella larvae for 7-9 d after application. These results are discussed in relation to their potential impact on insecticide resistance management strategie

    September 11: Perspectives From the Field of Philanthropy -- Volume Three

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    Assesses the philanthropic sector's response to September 11 through interviews with leaders in the field. Provides lessons learned in the government-philanthropic relief effort, highlighting unresolved public policy issues. Includes recommendations

    The Canadian Dementia Imaging Protocol: Harmonization validity for morphometry measurements

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    © 2019 The Authors The harmonized Canadian Dementia Imaging Protocol (CDIP) has been developed to suit the needs of a number of co-occurring Canadian studies collecting data on brain changes across adulthood and neurodegeneration. In this study, we verify the impact of CDIP parameters compliance on total brain volume variance using 86 scans of the same individual acquired on various scanners. Data included planned data collection acquired within the Consortium pour l\u27identification précoce de la maladie Alzheimer - Québec (CIMA-Q) and Canadian Consortium on Neurodegeneration in Aging (CCNA) studies, as well as opportunistic data collection from various protocols. For images acquired from Philips scanners, lower variance in brain volumes were observed when the stated CDIP resolution was set. For images acquired from GE scanners, lower variance in brain volumes were noticed when TE/TR values were within 5% of the CDIP protocol, compared to values farther from that criteria. Together, these results suggest that a harmonized protocol like the CDIP may help to reduce neuromorphometric measurement variability in multi-centric studies
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