Psychometric Properties of the Drive for Muscularity Attitudes Questionnaire Among Irish Men

The Drive for Muscularity Attitudes Questionnaire (DMAQ) was developed to measure men’s desire to attain an idealized muscular body. To date, the cross-cultural suitability of this measure has received limited attention. The current study addressed this omission by testing the psychometric properties of the DMAQ using an online sample of Irish men ( N = 327). Confirmatory factor analysis revealed that a unidimensional model adequately matched observed data (i.e., fit indices suggested acceptable model fit). Analyses also showed that the DMAQ yielded reliable and construct valid scores, suggesting that the scale holds promise as an indicant of the drive for muscularity among Irish men. Strengths and limitations associated with this study are discussed, such as advantages and disadvantages of Internet research. Directions for future research are given, including the need for more psychometric wor

Managing Complex Water Resource Systems for Ecological Integrity: Evaluating Tradeoffs and Uncertainty

Water resource systems often contain numerous components that are intertwined or contradictory, such as power production, water delivery, recreation, and environmental needs. This complexity makes it difficult to holistically assess management alternatives. In addition, hydroclimatic and ecological uncertainties complicate efforts to evaluate the impacts of management scenarios. We need new tools that are able to inform managers and researchers of the tradeoffs or consequences associated with flow alternatives, while also explicitly incorporating sources of uncertainty. My research addresses this limitation using two modeling approaches: stochastic system dynamics modeling and Bayesian network modeling. Specifically, the objectives of my research were 1) evaluate the impacts of environmental flow alternatives on other water users within a complex managed basin using stochastic system dynamics modeling; 2) assess the benefits of environmental flow alternatives on select ecological processes using stochastic system dynamics modeling; and 3) demonstrate the unique benefits of combining fine-scale hydrodynamic and Bayesian network models when assessing ecological responses to water management alternatives. I developed a stochastic system dynamics model to evaluate the impacts of environmental flow alternatives on multiple water users in the Rio Chama basin, New Mexico. This work examined the influence of flow alternatives on cottonwood recruitment, reservoir storage, hydropower production, and whitewater boating. In addition, I coupled two-dimensional hydrodynamic and Bayesian network models to assess the impacts of management scenarios on cottonwood recruitment on the Gila River, New Mexico. The Bayesian network approach explicitly incorporated spatial variability, as well as hydrologic and ecological uncertainties. These methods are useful for more thoroughly assessing the tradeoffs of management decisions, integrating system components within a holistic framework, and evaluating ecological consequences of management scenarios at fine spatial scales

The Zucker Rat as a Model of Obesity-Hypertension

Hypertension is a serious health problem that affects approximately 1 in 4 American adults. Most cases are diagnosed as essential hypertension, meaning that the exact cause is unknown. In most patients, however, excess weight is a major contributory factor to the development of essential hypertension. The role of obesity in promoting hypertension is now well documented and has become the foundation for an entire field of research known alternately as obesity-hypertension, obesity-induced hypertension, or obesity-associated hypertension. In this field, rapid advances are being made in our understanding of how obesity and hypertension are linked. A plethora of related risk factors, mediators, and pathways have now been identified and described through the use of a variety of animal models. Nonetheless, the relationships between these factors and the extents to which they promote obesity-hypertension are often poorly understood. Unscrambling the various cardiovascular and metabolic determinants of obesity- hypertension remains a persistent problem because both obesity and hypertension typically exhibit polygenic etiologies and diet-dependent dynamics in humans. The judicious use of appropriate animal models promises to be an important tool in this quest. In addition, animal models are vital platforms for designing and evaluating approaches to the treatment of obesity-hypertension. One model of particular interest is the obese Zucker rat, which develops extreme obesity but only develops slight, if any, hypertension. The primary objective of the research in this dissertation was to determine whether obese rats were more sensitive to experimental conditions known to induce hypertension than age- and gender-matched lean controls. Lean and obese Zucker rats were subjected to two experimental protocols that are known to induce hypertension in other rodent strains: (1) the administration of deoxycorticosterone-acetate and salt to uninephrectomized rats and (2) feeding rats a moderately high fat, salt-supplemented (MHF-SS) diet. In each case, the obese Zucker rat was found to be more susceptible to the development of hypertension. A second goal of this research was to ascertain a possible mechanism through which the MHF-SS diet might induce hypertension in obese Zucker rats. In this regard, dysfunction of the nitric oxide system, particularly in the kidney, was implicated in the pathogenesis of the MHF-SS diet in obese Zucker rats. In conclusion, this research suggests that the obese Zucker rat is labile with regard to blood pressure and that renal nitric oxide dysfunction may promote hypertension when obese Zucker rats are fed a moderately high fat, high salt diet

Nickel aluminum shape memory alloys via molecular dynamics

Shape memory materials are an important class of active materials with a wide range of applications in the aerospace, biomedical, and automobile industries. These materials exhibit the two unique properties of shape memory and superelasticity. Shape memory is the ability to recover its original shape by applying heat after undergoing large deformations. Superelasticity is the ability to undergo large, reversible deformations (up to 10%) that revert back when the load is removed. These special properties originate from a reversible, diffusionless solid-solid phase transformation that occurs between a high temperature austenite phase and a low temperature martensite phase. The development of the martensite microstructure is not well understood; this is especially true in regards to the role of size and mechanical constraints that dominate the properties in nanoscale samples. The goals of this research are to use molecular dynamics (MD) to (1) study the effects of simulation size on the martensite transformation to determine the ultimate limit of miniaturization, (2) to investigate the effects of mechanical constraints on the martensite transformation and resulting microstructure, and (3) to explore the effects of grain size in polycrystalline shape memory alloys. MD is well suited to study the transformation, as it shares a similar time scale with the extremely fast, diffusionless transformation.^ An extensive set of cooling and heating simulations were performed on Ni63Al37 disordered shape memory alloys (SMAs) to determine the effect of system size on the transformation. Simulation cell sizes in the range of 4.2 to 20 nm were studied. We discovered that decreasing system size only resulted in a slight increase of both transformation temperatures. However, the variability of the austenite transformation temperature increased considerably with decreasing simulation cell size, reaching 10% of the mean value for a system size of 10 nm. This variability can impose a fundamental limit on the miniaturization of this class of materials, as the reliability of device performance comes into question. Also, mechanical constraints were applied to force the cell angles to remain 90° in order to emulate the environment of a partially transformed polycrystal where grains are constricted by their neighbors. The mechanical constraints caused the austenite transformation temperature to decrease with decreasing size by up to 50%, and resulted in a two-domain microstructure for system sizes above 4.2 nm in order to accommodate the internal stresses. Finally, large scale MD simulations were done on polycrystalline samples with grain sizes ranging from 2.5 to 20 nm. We found that a critical grain size of 7.5 nm resulted in a minimum in the percent transformation to martensite. Below this critical size, martensite forms at the grain boundaries and the grains are able to rotate via grain boundary sliding to relieve internal stresses. In larger grains, martensite can nucleate and grow within the grains more easily. A uniaxial strain of up to 10% was applied to investigate the stress induced martensite transformation. Larger grains showed considerable work hardening when strained beyond about 2%. Plastic recovery was also calculated by unloading and relaxing at 4 and 10% strain. Samples strained to 10% were generally able to recover about 20-30% of the plastic strain, while samples strained to 4% showed varying amounts of recovery that peaked at 66% for a grain size of 7.5 nm

Exploring New Zealand’s Rural Education Activities Programmes (REAPs): Social capital in a lifelong learning and community development context : A thesis presented in partial fulfillment of the requirements for the degree of Doctorate of Education at Massey University, Palmerston North, New Zealand

This research explored the extent to which social capital is an approach used by New Zealand’s Rural Education Activities Programmes (REAPs) to contribute to rural education. Social capital was defined for the purposes of this study as the resource residing in networks of individuals, based on mutual trust and shared social norms, which can be brokered and mobilised to achieve social benefits, particularly in the application of knowledge and skills. A conceptual framework lays out four key elements from this definition which were investigated: networks, trust, social norms, and brokerage. Given the lack of published material on REAPs and their work, a primarily qualitative design was utilised. Set within a constructivist epistemology and interpretive phenomenological methodology, in-depth interviews with REAP managers and questionnaires for REAP learners were used to collect data. The aim was to explore the lived experiences of these two REAP groups to identify their views on how REAPs operate so that those views could be considered within the social capital framework above. An inductive-deductive-inductive analysis approach was used to maximise the extent to which findings reflected participant language. Findings from both REAP managers and learners supported the strong presence of the four social capital elements in REAP activity. In many cases the qualitative themes were closely related, both within and across the four social capital elements. Both strong (social) and weak (institutional) forms of trust were described as influencing learner participation in networks, where REAPs played a role in brokering that participation within similar (bonded) and differing (bridged) networks. REAPs made use of trusted relationships and valued-based decision making to gain local community and cultural knowledge to ensure the relevance of responsive learning activities. The result was enhanced confidence and identity of learners to take part in other social activities, including further learning and collective action. Lived examples of these elements supported a social capital approach that fit well with the lifelong learning and community development processes outlined by the REAP mandate. These processes were defined holistically to consider the integration of individuals’ beliefs, viewpoints, and behaviours as much as skills and knowledge. The explored social capital approach within lifelong learning and community development contexts, yields clear recommendations for Government, REAPs, and partner organisations. Flexibility, values/identity-based education, and closing network gaps to facilitate innovation come through as REAP social capital practices that could inform policy and partnerships across the whole of the education sector. Further research is needed to more closely consider the complex relationships of the identified social capital themes. In terms of emergent themes, a deeper exploration of innovation produced through brokerage within REAP activity is highlighted as a key area of research for future

Risk evaluations and condom use decisions of homeless youth: a multi-level qualitative investigation.

BackgroundHomeless youth are at higher risk for sexually transmitted infections and unwanted pregnancy than non-homeless youth. However, little is known about how they evaluate risk within the context of their sexual relationships. It is important to understand homeless youths' condom use decisions in light of their sexual relationships because condom use decisions are influenced by relationship dynamics in addition to individual attitudes and event circumstances. It is also important to understand how relationship level factors, sexual event circumstances, and individual characteristics compare and intersect.MethodsTo explore these issues, we conducted semi-structured interviews with 37 homeless youth in Los Angeles County in 2011 concerning their recent sexual relationships and analyzed the data using systematic methods of team-based qualitative data analysis.ResultsWe identified themes of risk-related evaluations and decisions at the relationship/partner, event, and individual level. We also identified three different risk profiles that emerged from analyzing how different levels of risk intersected across individual respondents. The three profiles included 1) Risk Takers, who consistently engage in risk and have low concern about consequences of risk behavior, 2) Risk Avoiders, who consistently show high concern about protection and consistently avoid risk, and 3) Risk Reactors, those who are inconsistent in their concerns about risk and protection and mainly take risks in reaction to relationship and event circumstances.ConclusionsInterventions targeting homeless youth should reflect multiple levels of risk behavior and evaluation in order to address the diversity of risk profiles. Relationship/partner-, event-, and individual-level factors are all important but have different levels of importance for different homeless youth. Interventions should be tailored to address the most important factor contributing to homeless youth reproductive needs

Clustering-based Redshift Estimation: Comparison to Spectroscopic Redshifts

We investigate the potential and accuracy of clustering-based redshift estimation using the method proposed by M\'enard et al. (2013). This technique enables the inference of redshift distributions from measurements of the spatial clustering of arbitrary sources, using a set of reference objects for which redshifts are known. We apply it to a sample of spectroscopic galaxies from the Sloan Digital Sky Survey and show that, after carefully controlling the sampling efficiency over the sky, we can estimate redshift distributions with high accuracy. Probing the full colour space of the SDSS galaxies, we show that we can recover the corresponding mean redshifts with an accuracy ranging from $\delta$z=0.001 to 0.01. We indicate that this mapping can be used to infer the redshift probability distribution of a single galaxy. We show how the lack of information on the galaxy bias limits the accuracy of the inference and show comparisons between clustering redshifts and photometric redshifts for this dataset. This analysis demonstrates, using real data, that clustering-based redshift inference provides a powerful data-driven technique to explore the redshift distribution of arbitrary datasets, without any prior knowledge on the spectral energy distribution of the sources.Comment: 13 pages. Submitted to MNRAS. Comments welcom