Implementation of periodic boundary conditions for loading of mechanical metamaterials and other complex geometric microstructures using finite element analysis

The implementation of periodic boundary conditions (PBCs) is one of the most important and difficult steps in the computational analysis of structures and materials. This is especially true in cases such as mechanical metamaterials which typically possess intricate geometries and designs which makes finding and implementing the correct PBCs a difficult challenge. In this work, we analyze one of the most common PBCs implementation technique, as well as implement and validate an alternative generic method which is suitable to simulate any possible 2D microstructural geometry with a quadrilateral unit cell regardless of symmetry and mode of deformation. A detailed schematic of how both these methods can be employed to study 3D systems is also presented.

     

Housing policy in remote Indigenous communities: how politics obstructs good policy

Abstract

When it comes to issues of housing policy, remote Indigenous housing often presents the extreme case. The failures of housing policy are most acute in remote Indigenous Australia, but despite the need to learn from the policy mistakes of the past, there has been little detailed analysis of the policy history. Through documentary and empirical analysis, we show that policies have either failed to be adapted to cultural and geographic contexts or, when they have been culturally responsive, they have lacked attention to the complexities of service delivery. Despite differences in policy settings, the long view is one of the normalization of Indigenous communities, although research points to the need for culturally appropriate arrangements. We argue that rather than politically motivated short-termism, governments need to develop a medium- to long-term approach that approaches policy solutions incrementally, builds capacity within the state and Indigenous communities, and is based on the evidence.     

Viral diffusion of technology products: a comprehensive stage framework

Information Systems and e-Business Management - The level of viral diffusion expected after a technology product or service is launched is important for determining the marketing budget,...     

Video game training to improve selective visual attention in older adults

The current study investigated the effect of video game training on older adult’s useful field of view performance (the UFOV® test). Fifty-eight older adult participants were randomized to receive practice with the target action game (Medal of Honor), a placebo control arcade game (Tetris), a clinically validated UFOV training program, or into a no contact control group. Examining pretest–posttest change in selective visual attention, the UFOV improved significantly more than the game groups; all three intervention groups improved significantly more than no-contact controls. There was a lack of difference between the two game conditions, differing from findings with younger adults. Discussion considers whether games posing less challenge might still be effective interventions for elders, and whether optimal training dosages should be higher.     

The colors of the alphabet: Naturally-biased associations between shape and color.

Many letters of the alphabet are consistently mapped to specific colors in English-speaking adults, both in the general population and in individuals with grapheme-color synaesthesia who perceive letters in color. Here, across six experiments, we tested the ubiquity of the color/letter associations with typically developing toddlers, literate children, and adults. We found that pre-literate children associate O with white and X with black and discovered that they also associate I and ameboid nonsense shapes with white; Z and jagged nonsense shapes with black; and C with yellow; but do not make a number of other associations (B blue; Y yellow; A red; G green) seen in literate children and adults. The toddlers' mappings were based on the shape and not the sound of the letter. The results suggest that sensory cortical organization initially binds specific colors to some specific shapes and that learning to read can induce additional associations, likely through the influence of higher order networks as letters take on meaning. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Composites with needle-like inclusions exhibiting negative thermal expansion: A preliminary investigation

In this work a simple cylindrical structure with a stiff needle-like inclusion embedded within a much softer matrix is presented and analysed with the aim of obtaining a system with tunable thermal expansion properties. It is shown that by the correct combination of the thermal and mechanical properties of the matrix and inclusion, it is possible to design a system which can be tailor-made to exhibit particular values of the coefficient of thermal expansion (CTE) in the radial direction and also negative thermal expansion (NTE). In particular an analytical model to quantify the radial strain with changes in temperature is derived and verified through finite element analysis. The model is used to find correct property combinations which lead to particular values of thermal expansion which could also be negative or zero.     

Studying protein–ligand interactions using protein crystallography

Protein X-ray crystallography is now a relatively high-throughput technique that plays a major role in structure-based drug design programs where the method of soaking small organic ligands into protein crystals is used to confirm or identify binding modes. In this review, we discuss some experimental approaches for ‘soaking-in’ ligands into protein crystals where the major problem is poor solubility of the ligand. We also provide examples showing how crystal soaking can be used as a technique for establishing ligand binding strength: K _c (the apparent ligand–protein dissociation constant in the crystal), which for some proteins at least, is found to be very similar to the solution K _d. Kinetic effects are also found to be important and the rate at which ligands soak into crystals is shown to vary by orders of magnitude from 10^?1 to 10⁷?s depending on the system.     

Redemptive Places,Charitable Choice,and Welfare Reform

The faces of the two girls featured in Danuta Rothschild's image Women's Shelter express both despair and hope. Part of a series of works on urban homelessness, the painting depicts them seated on the steps of a shelter for battered women. Such “redemptive places” and the hope they offer to desperate lives are the subject of Daphne Spain's Longer View. Spain recounts the inception of these places in the U.S. early in the last century and describes their latest incarnations in “Charitable Choice” initiatives.

Danuta Rothschild emigrated from Poland in 1971 and works daily in her studio in Venice, California. The subject matter of her paintings has included the Holocaust, Native Americans, threats of chemical war in the Middle East, and the natural world. Her work can be viewed on her Web site at <http://www.danutastudio.com> and she can be contacted at <danuta@danutastudio.com>.

A century ago, millions of Europeans, African Americans, and single women in search of work arrived in American cities. Religiously motivated volunteers met these newcomers with settlement houses, vocational schools, and boardinghouses that served as temporary respite from harsh urban conditions. Such “redemptive places” saved cities from demographic chaos by delivering social services to the poor well before the emergence of New Deal programs. Today, the federal government is actively promoting religious solutions to urban poverty. The “Charitable Choice” provision included in the 1996 welfare reform legislation makes faith-based organizations eligible to provide services to the poor. Redemptive places, therefore, are as important now as they were in the past. Planners can facilitate the creation of redemptive places by communicating the details of Charitable Choice to state and local agencies that outsource social services, identifying eligible properties, and reducing legal barriers to their existence.     

New dietetic practitioners' perspectives on their education and training

Purpose: To elucidate the complex phenomenon of dietitian professional socialization, we examined factors that influence people's decisions to pursue a career in dietetics and how education and training processes influence the professional socialization of dietitians. Methods: Participants (n=12) had less than three years of work experience and included alumni from three Canadian universities representing different models of entry to practice. Three one-on-one interviews were conducted with each participant. Results: The key influencing factor in participants' decision to pursue dietetics was the perceived congruence between dietetics and other aspects of their lives, including early interests and experiences (sports, food and cooking, an eating disorder), career aspirations (science, health care), and social networks (the desire to be a professional). A pivotal experience during high school or while enrolled in or after graduation from another program prompted participants' awareness of and subsequent decision to pursue a career in dietetics. Supportive relationships were vital to participants' professional socialization. Conclusions: Recruitment materials and education opportunities should help aspiring dietitians develop a clear idea of what being a dietitian means. Dietetic educators must attend to the informational and relational aspects involved in shaping future practitioners' dietitian identities.