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Simulation tools are playing an increasingly important role in materials science and engineering and beyond their well established importance in research and development, these tools have a significant pedagogical potential. We describe a set of online simulation tools and learning modules designed to help students explore important concepts in materials science where hands-on activities with high-fidelity simulations can provide insight not easily acquired otherwise. The online tools, which involve density functional theory and molecular dynamics simulations, have been designed with non-expert end-users in mind and only a few clicks are required to perform most simulations, yet they are powered by research-grade codes and expert users can access advanced options. All tools and modules are available for online simulation in nanoHUB.org and access is open and free of charge. Importantly, instructors and students do not need to download or install any software. The learning modules cover a range of topics from electronic structure of crystals and doping, plastic deformation in metals, and physical properties of polymers. These modules have been used in several core undergraduate courses at Purdue’s School of Materials Engineering, they are self contained, and are easy to incorporate into existing classes.
Hunter-gatherer lifestyles defined the origins of modern humans and for tens of thousands of years were the only form of subsistence our species knew. This changed with the advent of food production, which occurred at different times throughout the world. The chapters in this volume explore the different ways that hunter-gatherer societies around the world adapted to changing social and ecological circumstances while still maintaining a predominantly hunter-gatherer lifestyle. Couched specifically within the framework of resilience theory, the authors use contextualized bioarchaeological analyses of health, diet, mobility, and funerary practices to explore how hunter-gatherers responded to challenges and actively resisted change that diminished the core of their social identity and worldview.
According to many works on English phonology, word-final alveolar consonants – and only alveolar consonants – assimilate to following word-initial consonants, e.g. ran quickly → ra[ŋ] quickly. Some phonologists explain the readiness of alveolar consonants to assimilate (vs. the resistance of velar and labial articulations) by proposing that they have underspecified place of articulation (e.g. Avery & Rice 1989). Labial or dorsal nasals do not undergo assimilation because their place nodes are specified. There are reports that velar and labial consonants sometimes assimilate in English, but these are anecdotal observations, with no available audio and no statistics on their occurrence. We find evidence of assimilation of labial and velar nasals in the Audio British National Corpus, motivating a new, quantitative phonological framework: a statistical model of underspecification and variation which captures typical as well as less common but systematic patterns seen in non-coronal assimilation.
This review identifies priorities for beef cattle welfare research in the USA. Based on our professional expertise and synthesis of existing literature, we identify two themes in intensive aspects of beef production: areas where policy-based actions are needed and those where additional research is required. For some topics, considerable research informs best practice, yet gaps remain between scientific knowledge and implementation. For example, many of the risk factors and management strategies to prevent respiratory disease are understood, but only used by a relatively small portion of the industry. This is an animal health issue that will require leadership and discussion to gain widespread adoption of practices that benefit cattle welfare. There is evidence of success when such actions are taken, as illustrated by the recent improvements in handling at US slaughter facilities. Our highest priorities for additional empirical evidence are: the effect of technologies used to either promote growth or manage cattle in feedlots, identification of management risk factors for disease in feedlots, and management decisions about transport (rest stops, feed/water deprivation, climatic conditions, stocking density). Additional research is needed to inform science-based recommendations about environmental features such as dry lying areas (mounds), shade, water and feed, as well as trailer design.
Increased recognition of the business case for managing corporate impacts on the environment has helped drive increasingly detailed and quantified corporate environmental goals. Foremost among these are goals of no net loss (NNL) and net positive impact (NPI). We assess the scale and growth of such corporate goals. Since the first public, company-wide NNL/NPI goal in 2001, 32 companies have set similar goals, of which 18 specifically include biodiversity. Mining companies have set the most NNL/NPI goals, and the majority of those that include biodiversity, despite the generally lower total global impact of the mining industry on biodiversity compared to the agriculture or forestry industries. This could be linked to the mining industry's greater participation in best practice bodies, high-profile impacts, and higher profit margins per area of impact. The detail and quality of present goals vary widely. We examined specific NNL/NPI goals and assessed the extent to which their key components were likely to increase the effectiveness of these goals in benefiting biodiversity and managing business risk. Nonetheless, outcomes are more important than goals, and we urge conservationists to work with companies to both support and monitor their efforts to achieve increasingly ambitious environmental goals.
To assess the association of the acute-phase protein biomarkers, C-reactive protein (CRP) and α1-acid glycoprotein (AGP), with anaemia in children aged 6–59·9 months in Papua New Guinea.
A nationally representative household-based cross-sectional survey of children aged 6–59·9 months was used to assess the relationships between various combinations of elevated CRP (>5 mg/l) and AGP (>1·2 g/l) with anaemia. Logistic regression was used to determine if other factors, such as age, sex, measures of anthropometry, region, urban/rural residence and household size, modified or confounded the acute-phase protein–anaemia association.
Papua New Guinea.
A total of 870 children aged 6–59·9 months from the 2005 Papua New Guinea National Micronutrient Survey were assessed.
The following prevalence estimates were found: anaemia 48 %; elevated CRP 32 %; and elevated AGP 33 %. Children with elevated CRP had a prevalence of anaemia of 66 % compared with children with normal CRP who had a prevalence of 40 %. Corresponding estimates for AGP were 61 % and 42 %, respectively. Similar results were found with combinations of elevated CRP and AGP. The higher prevalence of anaemia in children with elevated CRP and/or AGP was still present after controlling for confounders.
Elevated levels of CRP and AGP were significantly associated with a higher prevalence of anaemia in the children surveyed. There are no expert group recommendations on whether to or how to account for markers of inflammation in presenting results on anaemia prevalence. Additional research would be helpful to clarify this issue.
The drive to reduce the thickness of solar cells is putting ever greater demands on light-trapping techniques. Techniques are required to improve absorption of light within the semiconductor, while not adversely affecting the electrical properties of the device. Conventional diffraction gratings can scatter visible and near-infrared photons into large angles, which get trapped in the silicon layer by total internal reflection. However, diffraction gratings typically have large feature sizes and so increase the overall surface area of a solar cell compared to the planar case. A periodic arrangement of metal nanoparticles acts as a diffraction grating, but an over-coated semiconductor will have a similar surface area to a planar layer due a combination of a low particle height and low surface coverage.
Random arrays of identical metal nanoparticles feature Lorentzian scattering peaks that can be tuned by modifying the size and shape of the particle. Periodic arrays have much more complicated scattering peaks, due to the enhancement and suppression of scattering at different wavelengths caused by the constructive and destructive interference between each nanoparticle. In effect the scattering spectrum of the individual nanoparticle is modified by the diffractive orders of the array, and so both parameters must be optimized together.
We have studied periodic arrays of metal nanoparticles fabricated using electron-beam lithography, and characterised their reflectance properties. The optical properties of the fabricated arrays were found to be in good agreement with finite-difference time-domain (FDTD) simulations. Au and Al nanoparticles are found to have a strong scattering effect and Al nanoparticles are also shown to exhibit an anti-reflection effect in combination with scattering. This work is focused on verifying that FDTD simulations can accurately model metal nanoparticle arrays and then extending the simulations to determine the previously unknown transmittance characteristics of metal nanoparticle arrays on silicon.
Childhood Programs and Practices in the First Decade of Life presents research findings on the effects of early childhood programs and practices in the first decade of life and their implications for policy development and reform. Leading scholars in the multidisciplinary field of human development and in early childhood learning discuss the effects and cost-effectiveness of the most influential model, state, and federally funded programs, policies, and practices. These include Head Start, Early Head Start, the WIC nutrition program, Nurse Family Partnership, and Perry Preschool as well as school reform strategies. This volume provides a unique multidisciplinary approach to understanding and improving interventions, practices, and policies to optimally foster human capital over the life course.
Barbara Devaney, Mathematica Policy Research, “WIC Turns 35: Program Effectiveness and Future Directions” (Chapter 2)
David L. Olds, University of Colorado Health Sciences Center, “The Nurse-Family Partnership: From Trials to Practice” (Chapter 3)
Frances A. Campbell, University of North Carolina, “Carolina Abecedarian Project” (coauthor: Craig T. Ramey, Georgetown University) (Chapter 4)
Q: “Why do the nurses produce larger effects than the paraprofessionals?”
SPEAKER DAVID OLDS:
A: First of all, the families visited by paraprofessionals did not open their doors to the visitors as they did for the nurses. It goes back to this point about families having to believe that this is worthwhile for them to engage in. The result is that the nurses completed more visits than paraprofessionals did. But the differences that we see between nurse-visited families and paraprofessional families are not simply explained by the quantitative results – the number of completed home visits. It looks like on a per-visit basis, the nurses are accomplishing more as well. I think that what we're seeing is that nurses are more successful in eliciting the kinds of behavioral changes and adaptive responses that we all would like to see than paraprofessionals are. I think that goes back to their basic training and clinical competence in being able to manage the complexities that they encounter in dealing with families with multiple issues regarding health, behavior, social contexts, and so forth, that make life hard.