122 research outputs found

    Role of Secondary Interactions (Ï€, agostic) as well as Solvent Influence on Alkali metal complexes

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    We here attempt to synthesize heterobimetallic alkali metal complexes with bulky phenolate ligands via solid state direct metallation. The solid state route may offer a facile method of producing these heterobimetallic species. Synthesis of heterobimetallic alkali metal compounds remains a challenge, as the homometallic complexes are generally favored over formation of the heterobimetallic species. Previous work has shown that the alkali metals have a strong solvent dependency; the recrystallization of heterobimetallic products from toluene yields the heterobimetallic, while recrystallization from THF yields the homometallic. However, the ability for phenolate ligands to stabilize metal centers through secondary interactions, such as M∙∙∙π interactions, has also been observed to compete with solvents in saturating the coordination spheres of the metals. A novel group of potassium-containing 1-D coordination polymers demonstrates the importance and role of K-Cp interactions. [K(Odpp)]∞, 1,(Odpp = 2,6-diphenylphenolate) forms a ladder-type polymer where extensive K-Cp interactions provide additional coordinative saturation. {[K2(Odpp)2H2O]2}∞, 2, consists of tetrameric cores of K4O6 polyhedra linked via a network of K-Cp interactions. Compound 2 displays not only inter- and intramolecular K-Cp contacts, but also several K-H agostic interactions that provide further coordinative saturation

    Tweeting For a Better World

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    Recognizing the need to build the social media capacity of nonprofits, the Rita Allen Foundation began a pilot project last spring, engaging the expertise and assistance of The Bridgespan Group, to help six grantees plan effective social media strategies. We and these six smaller-sized nonprofits (on average $1.8 million in annual revenue) worked together to determine if and how social media could advance each organization's mission, to develop implementation plans and measurement systems, and to collectively identify and address social media challenges

    Graduate midwives making a difference

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    Comparing Energy Expenditure During Land and Shallow Water Walking in Overweight and Obese Females

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    Introduction: The prevalence of overweight and obesity in the United States has reached epidemic levels. Reduction in body weight is of great importance for overweight and obese individuals through the increase in physical activity. One particular mode of physical activity that is currently growing in popularity is shallow water walking, although little research has been done examining the energy cost of this activity in an overweight and obese population. Purpose: To compare the energy expenditure (kcal/min) and rating of perceived exertion (RPE) of a bout shallow water walking at a self-selected pace to a bout of land walking at a matched heart rate response and to a bout of land walking at a self-selected pace in overweight and obese women. Methods: Nineteen participants completed three 10-minute experimental trials including a self-selected pace shallow water walking trial, a matched heart rate response land walking trial, and a self-selected pace land walking trial. Results: Significantly lower energy expenditure (p= 0.046) was observed for shallow water walking (6.46 ± 1.38 kcal/min) compared to the matched heart rate response land walking bout (7.26 ± 1.29 kcal/min), although no significant differences were detected for energy expenditure for shallow water walking and self-selected pace land walking (6.92 ± 1.61 kcal/min). No significant differences were detected for RPE across conditions (p=0.439). Exploratory analyses revealed correlations between measures of body composition (BMI and percent body fat) and the difference in energy expenditure between shallow water walking and matched heart rate response land walking. Conclusions: Findings from the current study suggest that although producing energy expenditure compared to heart rate matched land walking, shallow water walking is a viable alternative that can elicit and increase in energy expenditure performed at a moderate intensity, meeting ACSM criteria. Results of the exploratory analyses revealed an association between measures of body composition and differences in energy expenditure. Although only a limited number of participants of the present study had BMI’s above 35.0 kg/m2 (n=2), findings suggest that water exercise may be an alternative form of exercise and produce higher caloric expenditure at higher ranges of BMI and percent body fat

    THE RELATIONSHIP BETWEEN MUSCULOSKELETAL STRENGTH, PHYSIOLOGICAL CHARACTERISTICS, AND KNEE KINESTHESIA FOLLOWING FATIGUING EXERCISE

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    Fatiguing exercise may result in impaired functional joint stability and increased risk of unintentional injury. While there are several musculoskeletal and physiological characteristics related to fatigue onset, their relationship with proprioceptive changes following fatigue has not been examined. The purpose of this study was to establish the relationship between musculoskeletal and physiological characteristics and changes in proprioception, measured by threshold to detect passive motion (TTDPM), following fatiguing exercise. Twenty, physically active females participated (age: 28.65 ± 5.6 years, height: 165.6 ± 4.3 cm, weight: 61.8 ± 8.0 kg, BMI: 22.5± 2.3 kg/m2, BF: 23.3 ± 5.4%). During Visit 1, subjects completed an exercise history and 24-hour dietary questionnaire, and body composition, TTDPM familiarization, isokinetic knee strength, and maximal oxygen uptake/lactate threshold assessments. During Visit 2, subjects completed TTDPM and isometric knee strength testing prior to and following a fatiguing exercise protocol. Wilcoxon signed rank tests determined TTDPM and isometric knee strength changes from pre- to post- fatigue. Spearman’s rho correlation coefficients determined the relationship between strength and physiological variables with pre- to post-fatigue changes in TTDPM and with pre-fatigue and post-fatigue TTDPM in extension and flexion (α=0.05). No significant differences were demonstrated from pre-fatigue to post-fatigue TTDPM despite a significant decrease in isometric knee flexion strength (P<0.01) and flexion/extension ratio (P<0.05) following fatigue. No significant correlations were observed between strength or physiological variables and changes in TTDPM from pre- to post-fatigue in extension or flexion. Flexion/extension ratio was significantly correlated with pre-fatigue TTDPM in extension (r=-0.231, P<0.05). Peak oxygen uptake was significantly correlated with pre-fatigue (r=-0.500, P<0.01) and post-fatigue (r=-0.520, P<0.05) TTDPM in extension. No significant relationships were demonstrated between musculoskeletal and physiological characteristics and changes in TTDPM following fatigue. The results suggest that highly trained individuals may have better proprioception, and that the high fitness level of subjects in this investigation may have contributed to absence of TTDPM deficits following fatigue despite reaching a high level of perceptual and physiological fatigue. Future studies should consider various subject populations, other musculoskeletal strength characteristics, and different modalities of proprioception to determine the most important contributions to proprioceptive changes following fatigue

    How Warmth and Competence Stereotypes Predict Political Party Support

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    People use stereotypes and party affiliation when making voting decisions (Leeper, 1991). Voters are also known to support the political party they view positively (Graham, Nosek, & Haidt, 2012). How do stereotypes influence political party support? Since warmth and competence are used to evaluate social groups (Cuddy et al. 2008), we examined how the warmth and competence stereotypes associated with political parties were related to voter support. We surveyed participants using Amazon’s Mechanical Turk (n = 361). Participant’s ages ranged from twenty to seventy-three years old. These participants rated Democrats, Republicans, Independents, and Libertarians on competence, warmth, and support (Buhrmester, Kwang, & Gosling, 2011). We expect to find that competence and warmth for a political party (and their interaction) aids in predicting support for that party. To support our initial hypothesis we would need to find in our regressions that the more extensively a party was rated as warm or competent, the more participants support the party. Future research could take more political parties into account, such as the Green Party, or apply these predictive models to individual candidates. Research could also be expanded to examine using communion and agency towards parties as a predictive measure of elections

    Effect of Single Set Dynamic and Static Stretching Exercise on Jump Height in College Age Recreational Athletes

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    This study examined the effects of single set dynamic and static stretching on vertical jump height and hip and knee range of motion in a sample of college age recreational males. Forty-two males (aged 18-24) healthy, physically active volunteers participated as subjects in this investigation and were randomly assigned to one of three groups (1 set of 20 seconds dynamic stretch, 1 set of 20 second static stretch, or control). The knee and hip range of motion, sit and reach, and jump height were measured before and after the treatment condition. The same measures were performed on the control group that sat for 12 minutes. All subjects began with a five minute warm-up on a cycle ergometer. Following the warm-up period, subjects immediately began their stretching program. Results of the investigation showed significant changes from pre-to-post for all dependent measures (p \u3c 0.05). A significant difference between groups was found for sit and reach in the SS + DS groups (p \u3c 0.05). However, there were no significant differences between groups for jump height or knee and hip range of motion. The results of the present study suggest that static and dynamic stretching for 20 seconds prior to a vertical jump can improve vertical jump height and hip and knee range of motion in a sample of male college age recreational athletes. Future research is needed to investigate the effect of single set stretching exercise prior to activities requiring maximal force production that includes athletes and female subjects

    Energy Cost of Land and Shallow Water Walking in Females who are Overweight and Obese

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    Nineteen overweight or obese females completed three 10-minute experimental trials including a self-selected pace shallow water walking trial, a matched heart rate response land walking trial, and a self-selected pace land walking trial. Energy expenditure (kcal·min-1) was computed from expired gases assessed via indirect calorimetry. Results showed energy expenditure was lower (p= 0.046) during shallow water walking (6.46 ± 1.38 kcal·min-1) compared to matched heart rate response land walking trial (7.26 ± 1.29 kcal·min-1), with no significant difference in between shallow water and self-selected pace land walking (6.92 ± 1.61 kcal·min-1 ). The present study did not demonstrate superior energy cost of shallow water walking. However, results demonstrate that shallow water walking elicits an increase in energy expenditure, which may indicate that this form of activity is a reasonable alternative to land-based walking. Moreover, this form of activity may be particularly effective for individuals with mobility limitations during land-based exercise
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