1,170 research outputs found

    Subsurface Application of Herbicides

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    Traditional methods of preplant herbicide application often involve a broadcast spray followed by one or more incorporation passes. Incorporation reduces the amount of crop residue on the soil surface, which can lead to increased soil loss through wind and water erosion. Incorporation also distributes the herbicide more evenly throughout the soil profile, reducing chemical concentrations in the surface mixing zone. Chemicals located within the 1-2 em mixing zone contribute to herbicide losses with surface runoff (Mickelson et al., 1983; Baker et al., 1979). Conservation tillage, as defined by leaving a minimum of 30% of the soil surface covered by crop residue after planting, allows for incorporation of herbicides while still leaving adequate residue on the surface to reduce erosion losses. Although incorporation has been shown to be extremely effective in reducing surface runoff losses of herbicides, it also is the major contributor to reduced residue cover. No-till, the extreme end of conservation tillage, uses no tillage and maximized residue cover for maximum erosion control. Unfortunately, due to surface application of herbicides, no-till often prevents the use of the more volatile and moderately adsorbed herbicides. In some cases, no-till can increase herbicide concentration and losses with runoff water when compared to conventional tillage (Mickelson et al., 1995)

    Presence of Observers Increases One Repetition Maximum in College-age Males and Females

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    Purpose: To determine if the presence of observers affects muscular strength performance in college-age males and females. Methods: Twenty-five women and 24 men participated in the study. Two counter-balanced trials were performed in which participants completed 1-RM tests in bench press and leg press. During one trial, two members of the opposite gender observed the 1-RM tests. During the other trial there were no observers, other than the tester. Results: 1-RM for females increased 3.4±0.8 lbs on bench press (p\u3c.001) and increased 9.2±3.8 lbs on leg press (p=.025) when observers were present. 1-RM for males increased 4.2±1.1 lbs on bench press (p=.001) and increased 18.8±5.2 lbs on leg press (p=.002) with observers present. There was no difference in the percent increase in 1-RM between males and females for either leg press (p=.71) or bench press (p=.08). Conclusion: College-age males and females lifted more weight during a 1-RM test when observers were present

    Incipient order in the t-J model at high temperatures

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    We analyze the high-temperature behavior of the susceptibilities towards a number of possible ordered states in the t-J-V model using the high-temperature series expansion. From all diagrams with up to ten edges, reliable results are obtained down to temperatures of order J, or (with some optimism) to J/2. In the unphysical regime, t<J, large superconducting susceptibilities are found, which moreover increase with decreasing temperatures, but for t>J, these susceptibilities are small and decreasing with decreasing temperature; this suggests that the t-J model does not support high-temperature superconductivity. We also find modest evidence of a tendency toward nematic and d-density wave orders. ERRATUM: Due to an error in the calculation, the series for d-wave supeconducting and extended s-wave superconducting orders were incorrect. We recalculate the series and give the replacement figures. In agreement with our earlier findings, we still find no evidence of any strong enhancement of the superconducting susceptibility with decreasing temperature. However, because different Pade approximants diverge from each other at somewhat higher temperatures than we originally found, it is less clear what this implies concerning the presence or absence of high-temperature superconductivity in the t-J model.Comment: 4 pages, 5 eps figures included; ERRATUM 2 pages, 3 eps figures correcting the error in the series for superconducting susceptibilitie

    Complexity of childhood sexual abuse: predictors of current post-traumatic stress disorder, mood disorders, substance use, and sexual risk behavior among adult men who have sex with men

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    Men who have sex with men (MSM) are the group most at risk for HIV and represent the majority of new infections in the United States. Rates of childhood sexual abuse (CSA) among MSM have been estimated as high as 46 %. CSA is associated with increased risk of HIV and greater likelihood of HIV sexual risk behavior. The purpose of this study was to identify the relationships between CSA complexity indicators and mental health, substance use, sexually transmitted infections, and HIV sexual risk among MSM. MSM with CSA histories (n = 162) who were screened for an HIV prevention efficacy trial completed comprehensive psychosocial assessments. Five indicators of complex CSA experiences were created: CSA by family member, CSA with penetration, CSA with physical injury, CSA with intense fear, and first CSA in adolescence. Adjusted regression models were used to identify relationships between CSA complexity and outcomes. Participants reporting CSA by family member were at 2.6 odds of current alcohol use disorder (OR 2.64: CI 1.24–5.63), two times higher odds of substance use disorder (OR 2.1: CI 1.02–2.36), and 2.7 times higher odds of reporting an STI in the past year (OR 2.7: CI 1.04–7.1). CSA with penetration was associated with increased likelihood of current PTSD (OR 3.17: CI 1.56–6.43), recent HIV sexual risk behavior (OR 2.7: CI 1.16–6.36), and a greater number of casual sexual partners (p = 0.02). Both CSA with Physical Injury (OR 4.05: CI 1.9–8.7) and CSA with Intense Fear (OR 5.16: CI 2.5–10.7) were related to increased odds for current PTSD. First CSA in adolescence was related to increased odds of major depressive disorder. These findings suggest that CSA, with one or more complexities, creates patterns of vulnerabilities for MSM, including post-traumatic stress disorder, substance use, and sexual risk taking, and suggests the need for detailed assessment of CSA and the development of integrated HIV prevention programs that address mental health and substance use comorbidities.This study was supported by a Grant from the NIMH (R01 MH095624) PI: O'Cleirigh; Author time (Safren) was supported, in part, by Grant 5K24MH094214. (R01 MH095624 - NIMH; 5K24MH094214)Accepted manuscrip
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