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We identify and characterize a new class of fingering instabilities in liquid metals; these instabilities are unexpected due to the large interfacial tension of metals. Electrochemical oxidation lowers the effective interfacial tension of a gallium-based liquid metal alloy to values approaching zero, thereby inducing drastic shape changes, including the formation of fractals. The measured fractal dimension (D=1.3±0.05) places the instability in a different universality class than other fingering instabilities. By characterizing changes in morphology and dynamics as a function of droplet volume and applied electric potential, we identify the three main forces involved in this process: interfacial tension, gravity, and oxidative stress. Importantly, we find that electrochemical oxidation can generate compressive interfacial forces that oppose the tensile forces at a liquid interface. The surface oxide layer ultimately provides a physical and electrochemical barrier that halts the instabilities at larger positive potentials. Controlling the competition between interfacial tension and oxidative (compressive) stresses at the interface is important for the development of reconfigurable electronic, electromagnetic, and optical devices that take advantage of the metallic properties of liquid metals. [ABSTRACT FROM AUTHOR]

Agency and its role in the early literacy classroom has long been a topic for debate. While sociocultural accounts often portray the child as a cultural agent who negotiates their own participation in classroom culture and literacy learning, more recent framings draw attention from the individual subject, instead seeing agency as dispersed across people and materials. In this article, I draw on my experiences of following children as they followed their interests in an early literacy classroom, drawing on the concepts of assemblage and people yet to come, as defined by Deleuze and Guattari and Spinoza's common notion. I provide one illustrative account of moment-by-moment activity and suggest that in education settings it is useful to see activity as a direct and ongoing interplay of three dimensions: children's moving bodies; the classroom; and its materials. I propose that children's ongoing movements create possibilities for 'doing' and 'being' that flow across and between children. I argue that thinking with assemblages can draw attention to both the potentiality and the power dynamics inherent in the ongoing present and also counter preconceived notions of individual child agency and linear trajectories of literacy development, and the inequalities that these concepts can perpetuate within early education settings. [ABSTRACT FROM AUTHOR]

This paper reports on an analysis of patterns of children's bodily movements in an Early Years classroom. I illustrate two prevalent patterns identified during close observations of children's walking movements as they as they followed their interests while accessing continuous provision in an Early Years setting in England. I termed the patterned pathways movement/ interest formations and draw a relationship between these formations and affective atmospheres, suggesting that these atmospheres were created by the dynamics and flows of children's ongoing bodily movements. I propose that affective atmospheres and movement/interest formations are intricately connected to child-produced meanings as children re-imagine, re-shape and re-purpose classroom spaces and materials. In this way I contribute to conceptual understandings role of children's whole bodily movements and the accompanying affective atmospheres in the emergence of young children's literacy practices. My findings substantiate viewpoints that children should be provided with the opportunity to engage in exploratory play and move freely in education settings. Furthermore, I suggest that practitioners be attuned to the the affective dimensions of young children's emerging literacy practices in Early Years classrooms. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the author discusses articles within the issue on topics including English as a foreign language in China, impact of culturally relevant pedagogies on young learners, and Native American youth finding identity through digital storytelling.

An introduction is presented in which author discusses articles on topics including focuses on different practices around the teaching of writing and explore student teachers' perceptions of creativity and its role in teaching writing in the primary school.

Various modes of cardiac stress testing are conducted in outpatient practices today. This article presents information on the current methods of testing to help primary care providers gain confi dence in test selection, the testing process, and interpreting results. [ABSTRACT FROM AUTHOR]

Abstract Youth gang involvement is a serious public health challenge and there is limited research with adolescents on their understandings of adolescent gang involvement, particularly in low-and middle-income countries (LMICs). This paper reports on the key theme of adolescents' experiences of youth gangs which emerged from qualitative research exploring adolescents' experiences of daily life. Six focus groups and 10 individual interviews were conducted with adolescents aged 13–14 years. Four factors were identified as protective against gang involvement; access to resources, school achievement, positive peer influences and supportive adult relationships. These findings illustrate the multiple factors which contribute to youth gang involvement and highlight the need for interventions to take an integrated and uniform approach to reduce risk factors and increase protective factors at the individual, family, school and community level. [ABSTRACT FROM AUTHOR]

On a sufficiently soft substrate, a resting fluid droplet will cause significant deformation of the substrate. This deformation is driven by a combination of capillary forces at the contact line and the fluid pressure at the solid surface. These forces are balanced at the surface by the solid traction stress induced by the substrate deformation. Young's Law, which predicts the equilibrium contact angle of the droplet, also indicates an a priori radial force balance for rigid substrates, but not necessarily for soft substrates that deform under loading. It remains an open question whether the contact line transmits a non-zero force tangent to the substrate surface in addition to the conventional normal (vertical) force. We present an analytic Fourier transform solution technique that includes general interfacial energy conditions, which govern the contact angle of a 2D droplet. This includes evaluating the effect of gravity on the droplet shape in order to determine the correct fluid pressure at the substrate surface for larger droplets. Importantly, we find that in order to avoid a strain singularity at the contact line under a non-zero tangential contact line force, it is necessary to include a previously neglected horizontal traction boundary condition. To quantify the effects of the contact line and identify key quantities that will be experimentally accessible for testing the model, we evaluate solutions for the substrate surface displacement field as a function of Poisson's ratio and zero/non-zero tangential contact line forces. [ABSTRACT FROM PUBLISHER]

An editorial is presented on the research from different perspectives on human communication and embraces the embodied, multilingual and culturally diverse nature of oracy. It offers a counter narrative to such reductive discourses, and expose the inequalities that such perspectives produce, perpetuate, and uphold. An overview of the classrooms in multilingual contexts in South Africa, the U.S., Zambia, Australia with standard English dominated curricular mandates is presented.

Photoelastic techniques are used to make both qualitative and quantitative measurements of the forces within idealized granular materials. The method is based on placing a birefringent granular material between a pair of polarizing filters, so that each region of the material rotates the polarization of light according to the amount of local stress. In this review paper, we summarize the past work using the technique, describe the optics underlying the technique, and illustrate how it can be used to quantitatively determine the vector contact forces between particles in a 2D granular system. We provide a description of software resources available to perform this task, as well as key techniques and resources for building an experimental apparatus. [ABSTRACT FROM AUTHOR]

The author discusses publishing papers related to qualitative research and its publishing in health systems. He comments on an open letter written to the editors of "British Medical Journal (BMI)." He states that the letter has triggered a debate in the health system by systems researchers and health policy researchers, and mentions that restricting of publication to quantitative research.

Exposure to violence is a serious mental and public health issue. In particular, children exposed to violence are at risk for poor developmental outcomes and physical and mental health problems. One area that has been shown to increase the risk for poor outcomes is the use of corporal punishment as a discipline method. While researchers are starting to ask children directly about their experiences of violence, there is limited research with children about their perspectives on physical punishment, particularly in low-and middle-income countries (LMIC). This paper begins to address this gap by reporting on the spontaneous data that emerged during 24 qualitative interviews that were conducted with children, aged 8–12 in South Africa. The themes that emerged indicated that corporal punishment is an everyday experience, that it has negative emotional and behavioral consequences, and that it plays a role in how children resolve interpersonal conflicts. The study highlights the challenges for violence prevention interventions in under-resourced contexts. [ABSTRACT FROM AUTHOR]

Introduction: Alcohol administration studies assessing alcohol's deleterious effects on women's threat perception and response in potential sexual assault situations usually employ a moderate to high dose (.07% BAC or more) and measure alcohol's effects specifically on women's sexual decisions. The current study used a low dose (.03%, equivalent to about 1-2 drinks) to assess women's projected decisions on a different risky behavior: decisions to continue drinking and to drink higher amounts in a series of ecologically-valid sexual risk situations.Methods: Young adult women (n=17; M age=21.8, SD=1.3, range 21-25) participated in a three-session double-blind within subjects 2 (type of scenario)×3( beverage) experiment, responding each time to 6 vignettes with an attractive man who was either Familiar or had Just Met her. In each session participants consumed a beverage (alcohol, placebo or water, random order) and projected emotional reactions and drinking decisions (likelihood and amount) in each of the 6 scenarios.Results: Regardless of beverage, women predicted greater happiness, drinking likelihood, and drinking amount with "Familiar" men. However, there was also an interaction: they projected increased subsequent amounts in the .03% BAC (vs. water and placebo) condition differentially in the "Familiar" scenarios.Conclusion: When the woman is Familiar with the man in a risky sexual situation, just one drink may increase subsequent projected alcohol amount over that originally intended. Implications include a low dose as a possible prime for more drinking, increasing sexual assault risk. [ABSTRACT FROM AUTHOR]

Introduction Alcohol administration studies assessing alcohol's deleterious effects on women's threat perception and response in potential sexual assault situations usually employ a moderate to high dose (.07% BAC or more) and measure alcohol's effects specifically on women's sexual decisions. The current study used a low dose (.03%, equivalent to about 1–2 drinks) to assess women's projected decisions on a different risky behavior: decisions to continue drinking and to drink higher amounts in a series of ecologically-valid sexual risk situations. Methods Young adult women ( n = 17; M age = 21.8, SD = 1.3, range 21–25) participated in a three-session double-blind within subjects 2 (type of scenario) × 3( beverage) experiment, responding each time to 6 vignettes with an attractive man who was either Familiar or had Just Met her. In each session participants consumed a beverage (alcohol, placebo or water, random order) and projected emotional reactions and drinking decisions (likelihood and amount) in each of the 6 scenarios. Results Regardless of beverage, women predicted greater happiness, drinking likelihood, and drinking amount with “Familiar” men. However, there was also an interaction: they projected increased subsequent amounts in the .03% BAC (vs. water and placebo) condition differentially in the “Familiar” scenarios. Conclusion When the woman is Familiar with the man in a risky sexual situation, just one drink may increase subsequent projected alcohol amount over that originally intended. Implications include a low dose as a possible prime for more drinking, increasing sexual assault risk. [ABSTRACT FROM AUTHOR]

Background: Within the integrated community case management of childhood illnesses (iCCM) programme, the traditional health promotion and prevention role of community health workers (CHWs) has been expanded to treatment. Understanding both the impact and the implementation experience of this expanded role are important. In evaluating UNICEF’s implementation of iCCM, this qualitative case study explores the implementation experience in Ghana. Methods and Findings: Data were collected through a rapid appraisal using focus groups and individual interviews during a field visit in May 2013 to Accra and the Northern Region of Ghana. We sought to understand the experience of iCCM from the perspective of locally based UNICEF staff, their partners, researchers, Ghana health services management staff, CHWs and their supervisors, nurses in health facilities and mothers receiving the service. Our analysis of the findings showed that there is an appreciation both by mothers and by facility level staff for the contribution of CHWs. Appreciation was expressed for the localisation of the treatment of childhood illness, thus saving mothers from the effort and expense of having to seek treatment outside of the village. Despite an overall expression of value for the expanded role of CHWs, we also found that there were problems in supporting and sustaining their efforts. The data showed concern around CHWs being unpaid, poorly supervised, regularly out of stock, lacking in essential equipment and remaining outside the formal health system. Conclusions: Expanding the roles of CHWs is important and can be valuable, but contextual and health system factors threaten the sustainability of iCCM in Ghana. In this and other implementation sites, policymakers and key donors need to take into account historical lessons from the CHW literature, while exploring innovative and sustainable mechanisms to secure the programme as part of a government owned and government led strategy. [ABSTRACT FROM AUTHOR]

The author discusses the importance of social science approaches in redressing inequity in health and publication of health research in 2017. Topics covered include the need to use embedded social science in answering questions in the field of health policy and systems research (HSPR) and to integrate observations and interactions that occur between patients, providers, and policymakers. Also noted is social science's role in health systems during the Ebola virus disease outbreak in 2014-16.

Thermal fluctuations, geometric exclusion, and external driving all govern the mechanical response of dense particulate suspensions. Here, we measure the stress-strain response of quasi-two-dimensional flow-stabilized microsphere heaps in a regime in which all three effects are present using a microfluidic device. We observe that the elastic modulus and the mean interparticle separation of the heaps are tunable via the confining stress provided by the fluid flow. Furthermore, the measured stress-strain curves exhibit a universal nonlinear shape, which can be predicted from a thermal van der Waals equation of state with excluded volume. This analysis indicates that many-body interactions contribute a significant fraction of the stress supported by the heap. [ABSTRACT FROM AUTHOR]

This paper discusses the ways in which young children collaboratively use narrative play and the available space and materials around them in order to exert cultural agency. The collaborative creation of texts is asserted as central to this expression of agency. By presenting an illustrative vignette of a group of 5-year-old boys as they engage in literacy practices and create a range of meaningful texts within an early years compulsory education setting, the ways in which agency is expressed through the collaborative venture of text creation is explored. The vignette follows an episode of self-initiated dramatic play, fuelled by the children's desire to engage in peer culture and make meanings collaboratively. This play episode spurs the creation of a range of hybridised texts, which culminate in the production of a written narrative. Observations from this study are then used to add to a broader discussion, which raises concerns about the current policy in England, which views early writing development as a set of individual and predefined set of skills to be acquired, a view which could undervalue the experiences that children bring to early educational settings. [ABSTRACT FROM AUTHOR]

Powders and grains exhibit unpredictable jamming-to-flow transitions that manifest themselves on geophysical scales in catastrophic slip events such as landslides and earthquakes, and on laboratory/industrial scales in profound processing difficulties. Over the past few years, insight into these transitions has been provided by new evidence that slip events may be accompanied, or even preceded, by electrical effects. In the present work, we quantify the correlation between slip and the separation of electrical charges, using an archetypal granular material: photoelastic polymers. We measure a strong correlation between material displacement, acoustic emissions, and voltage. We find that the generation of voltage is associated with surface, rather than bulk properties of the granular materials. While voltage precursors are only occasionally observed in this system, there is some asymmetry in the cross-correlation between the slip and voltage signals that indicates differences between the pre- and post-slip dynamics. [ABSTRACT FROM AUTHOR]

Dryland ecosystems commonly exhibit periodic bands of vegetation, thought to form due to competition between individual plants for heterogeneously distributed water. In this paper, we develop a Fourier method for locally identifying the pattern wavenumber and orientation, and apply it to aerial images from a region of vegetation patterning near Fort Stockton, TX, USA. We find that the local pattern wavelength and orientation are typically coherent, but exhibit both rapid and gradual variation driven by changes in hillslope gradient and orientation, the potential for water accumulation, or soil type. Endogenous pattern dynamics, when simulated for spatially homogeneous topographic and vegetation conditions, predict pattern properties that are much less variable than the orientation and wavelength observed in natural systems. Our local pattern analysis, combined with ancillary datasets describing soil and topographic variation, highlights a largely unexplored correlation between soil depth, pattern coherence, vegetation cover and pattern wavelength. It also, surprisingly, suggests that downslope accumulation of water may play a role in changing vegetation pattern properties. [ABSTRACT FROM AUTHOR]

A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact line in a starburst pattern. In this paper, we characterize (i) the initiation process, in which the number of arms in the starburst is controlled by the ratio of the surface tension contrast to the gel's elastic modulus, and (ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law L ∝ t3/4. We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid-solid wetting forces. The elastic solution shows that both the location and the magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids, finding that the latter better explains the observed exponent. [ABSTRACT FROM AUTHOR]

Although jammed granular systems are athermal, several thermodynamiclike descriptions have been proposed which make quantitative predictions about the distribution of volume and stress within a system and provide a corresponding temperaturelike variable. We perform experiments with an apparatus designed to generate a large number of independent, jammed, two-dimensional configurations. Each configuration consists of a single layer of photoelastic disks supported by a gentle layer of air. New configurations are generated by cyclically dilating, mixing, and then recompacting the system through a series of boundary displacements. Within each configuration, a bath of particles surrounds a smaller subsystem of particles with a different interparticle friction coefficient than the bath. The use of photoelastic particles permits us to find all particle positions as well as the vector forces at each interparticle contact. By comparing the temperaturelike quantities in both systems, we find compactivity (conjugate to the volume) does not equilibrate between the systems, while the angoricity (conjugate to the stress) does. Both independent components of the angoricity are linearly dependent on the hydrostatic pressure, in agreement with predictions of the stress ensemble. [ABSTRACT FROM AUTHOR]

The process of clustering groups together data points so that intra-cluster similarity is maximized while inter-cluster similarity is minimized. Support vector clustering (SVC) is a clustering approach that can identify arbitrarily shaped cluster boundaries. The execution time of SVC depends heavily on several factors: choice of the width of a kernel function that determines a nonlinear transformation of the input data, solution of a quadratic program, and the way that the output of the quadratic program is used to produce clusters. This paper builds on our prior SVC research in two ways. First, we propose a method for identifying a kernel width value in a region where our experiments suggest that clustering structure is changing significantly. This can form the starting point for efficient exploration of the space of kernel width values. Second, we offer a technique, called cone cluster labeling, that uses the output of the quadratic program to build clusters in a novel way that avoids an important deficiency present in previous methods. Our experimental results use both two-dimensional and high-dimensional data sets. [ABSTRACT FROM AUTHOR]

Experiments quantifying the rotational and translational motion of particles in a dense, driven, 2D granular gas floating on an air table reveal that kinetic energy is divided equally between the two translational and one rotational degrees of freedom. This equipartition persists when the particle properties, confining pressure, packing density, or spatial ordering are changed. While the translational velocity distributions are the same for both large and small particles, the angular velocity distributions scale with the particle radius. The probability distributions of all particle velocities have approximately exponential tails. Additionally, we find that the system can be described with a granular Boyle's law with a van der Waals-like equation of state. These results demonstrate ways in which conventional statistical mechanics can unexpectedly apply to nonequilibrium systems. [ABSTRACT FROM AUTHOR]

How do aging and prior knowledge affect memory and metamemory? We explored this question in the context of a dual-process approach to Judgments of Learning (JOLs), which require people to predict their ability to remember information at a later time. Young and older adults (n = 36, mean ages = 20.2 & 73.1) studied the names of actors who were famous in the 1950s or 1990s, providing a JOL for each. Recognition memory for studied and unstudied actors was then assessed using a Recollect/Know/No-Memory (R/K/N) judgment task. Results showed that prior knowledge increased recollection in both age groups such that older adults recollected significantly more 1950s actors than younger adults. Also, for both age groups and both decades, actors judged R at test garnered significantly higher JOLs at study than actors judged K or N. However, while the young showed benefits of prior knowledge on relative JOL accuracy, older adults did not, showing lower levels of JOL accuracy for 1950s actors despite having higher recollection for, and knowledge about, those actors. Overall, the data suggest that prior knowledge can be a double-edged sword, increasing the availability of details that can support later recollection, but also increasing nondiagnostic feelings of familiarity that can reduce the accuracy of memory predictions. [ABSTRACT FROM AUTHOR]

Background: While the past two decades have seen a shift towards evidence-based obstetrics and midwifery, the process through which a culture of evidence-based practice develops and is sustained within particular fields of clinical practice has not been well documented, particularly in LMICs (low- and middle-income countries). Forming part of a broader qualitative study of evidence-based policy making, this paper describes the development of a culture of evidence-based practice amongst maternal health policy makers and senior academic obstetricians in South Africa Methods: A qualitative case-study approach was used. This included a literature review, a policy document review, a timeline of key events and the collection and analysis of 15 interviews with policy makers and academic clinicians involved in these policy processes and sampled using a purposive approach. The data was analysed thematically. Results: The concept of evidence-based medicine became embedded in South African academic obstetrics at a very early stage in relation to the development of the concept internationally. The diffusion of this concept into local academic obstetrics was facilitated by contact and exchange between local academic obstetricians, opinion leaders in international research and structures promoting evidence-based practice. Furthermore the growing acceptance of the concept was stimulated locally through the use of existing professional networks and meetings to share ideas and the contribution of local researchers to building the evidence base for obstetrics both locally and internationally. As a testimony to the extent of the diffusion of evidence-based medicine, South Africa has strongly evidence-based policies for maternal health. Conclusion: This case study shows that the combined efforts of local and international researchers can create a culture of evidence-based medicine within one country. It also shows that doing so required time and perseverance from international researchers combined with a readiness by local researchers to receive and actively promote the practice. [ABSTRACT FROM AUTHOR]

Background: Even though it has been shown that peer support to mothers at home helps to increase exclusive breastfeeding, little is known about the experiences of peer supporters themselves and what is required of them to fulfil their day-to-day tasks. Therefore, a community-based randomised control trial using trained "lay" women to support exclusive infant feeding at home was implemented in three different sites across South Africa. The aim of this paper is to describe the experiences of peer supporters who promote exclusive infant feeding. Methods: Three focus group discussions were held, in a language of their choice, with peer supporters. These meetings focused on how the peer educators utilised their time in the process of delivering the intervention. Data from the discussions were transcribed, with both verbatim and translated transcripts being used in the analysis. Results: Unlike the services provided by mainstream health care, peer supporters had to market their services. They had to negotiate entry into the mother's home and then her life. Furthermore, they had to demonstrate competence and come across as professional and trustworthy. An HIV-positive mother's fear of being stigmatised posed an added burden - subsequent disclosure of her positive status would lead to an increased workload and emotional distress. Peer supporters spent most of their time in the field and had to learn the skill of selfmanagement. Their support-base was enhanced when supervision focused on their working conditions as well as the delivery of their tasks. Despite this, they faced other insurmountable issues, such as mothers being compelled to offer their infants mixed feeding simultaneously due to normative practices and working in the fields postpartum. Conclusion: Designers of peer support interventions should consider the skills required for delivering health messages and the skills required for selling a service. Supportive supervision should be responsive both to the health care task and the challenges faced in the process of delivering it. Trial registration: NCT00297150. [ABSTRACT FROM AUTHOR]

Spatial ecological patterns are usually ascribed to Turingtype reaction-diffusion or scale-dependent feedback processes, but morphologically indistinguishable patterns can be produced by instabilities in fluid flow. We present a new hypothesis that suggests that fluid convection and chill damage to plants could form vegetation patterns with wavelengths ~1-2 times the plant height. Previous hypotheses for small-scale vegetation pattern formation relied on a Turing process driven by competition for water, which is thought to occur in large vegetation patterns. Predictions of the new hypothesis were consistent with properties of natural grass patterns in North Carolina, contradicting the Turing hypothesis. These results indicate that similarities in pattern morphology should not be interpreted as implying similarities in the pattern-forming processes, that small-wavelength vegetation patterns may arise from mechanisms that are distinct from those generating long-wavelength vegetation patterns, and that fluid instabilities should be recognized as a cause of ecological patterns. [ABSTRACT FROM AUTHOR]

Background: Recent years have seen a re-emergence of community health worker (CHW) interventions, especially in relation to HIV care, and in increasing coverage of child health interventions. Such programmes can be particularly appealing in the face of human resource shortages and fragmented health systems. However, do we know enough about how these interventions function in order to support the investment? While research based on strong quantitative study designs such as randomised controlled trials increasingly document their impact, there has been less empirical analysis of the internal mechanisms through which CHW interventions succeed or fail. Qualitative process evaluations can help fill this gap.Methods: This qualitative paper reports on the experience of three CHW supervisors who were responsible for supporting infant feeding peer counsellors. The intervention took place in three diverse settings in South Africa. Each setting employed one CHW supervisor, each of whom was individually interviewed for this study. The study forms part of the process evaluation of a large-scale randomized controlled trial of infant feeding peer counselling support.Results: Our findings highlight the complexities of supervising and supporting CHWs. In order to facilitate effective infant feeding peer counselling, supervisors in this study had to move beyond mere technical management of the intervention to broader people management. While their capacity to achieve this was based on their own prior experience, it was enhanced through being supported themselves. In turn, resource limitations and concerns over safety and being in a rural setting were raised as some of the challenges to supervision. Adding to the complexity was the issue of HIV. Supervisors not only had to support CHWs in their attempts to offer peer counselling to mothers who were potentially HIV positive, but they also had to deal with supporting HIV-positive peer counsellors.Conclusions: This study highlights the need to pay attention to the experiences of supervisors so as to better understand the components of supervision in the field. Such understanding can enhance future policy making, planning and implementation of peer community health worker programmes. [ABSTRACT FROM AUTHOR]

Dual-process theories propose that episodic memory performance reflects both recollection of prior details as well as more automatic influences of the past. The authors explored the idea that recollection mediates the accuracy of judgments of learning (JOLs) and may also help explain age differences in JOL accuracy. Young and older adults made immediate JOLs at study and then completed recognition or recall tests that included a recollect/familiar judgment. JOLs were found to be strongly related to recollected items but not to items remembered on the basis of familiarity. The pattern was weaker in older adults, consistent with age-related declines in recollection. [ABSTRACT FROM AUTHOR]

This case study uses documentation as a tool for formative assessment to interpret the learning of twin boys with significantly delayed language skills. Reggio-inspired documentation (the act of collecting, interpreting, and reflecting on traces of learning from video, images, and observation notes) focused on the unfolding of the boys' nonverbal communication skills that helped inform planning and implementing instruction. Documentation is displayed, with an interpretation of the learning and a demonstration of the boys' strengths and competencies. The authors discuss how a public display of documentation sparked a collaborative inquiry among teachers, family, and the children themselves. Implications for practice outline guidelines in using documentation to assess learning. [ABSTRACT FROM AUTHOR]

Background: Little is known about the process of knowledge translation in low- and middle-income countries. We studied policymaking processes in Mozambique, South Africa and Zimbabwe to understand the factors affecting the use of research evidence in national policy development, with a particular focus on the findings from randomized control trials (RCTs). We examined two cases: the use of magnesium sulphate (MgSO(4)) in the treatment of eclampsia in pregnancy (a clinical case); and the use of insecticide treated bed nets and indoor residual household spraying for malaria vector control (a public health case).Methods: We used a qualitative case-study methodology to explore the policy making process. We carried out key informants interviews with a range of research and policy stakeholders in each country, reviewed documents and developed timelines of key events. Using an iterative approach, we undertook a thematic analysis of the data.Findings: Prior experience of particular interventions, local champions, stakeholders and international networks, and the involvement of researchers in policy development were important in knowledge translation for both case studies. Key differences across the two case studies included the nature of the evidence, with clear evidence of efficacy for MgSO(4 )and ongoing debate regarding the efficacy of bed nets compared with spraying; local researcher involvement in international evidence production, which was stronger for MgSO(4 )than for malaria vector control; and a long-standing culture of evidence-based health care within obstetrics. Other differences were the importance of bureaucratic processes for clinical regulatory approval of MgSO(4), and regional networks and political interests for malaria control. In contrast to treatment policies for eclampsia, a diverse group of stakeholders with varied interests, differing in their use and interpretation of evidence, was involved in malaria policy decisions in the three countries.Conclusion: Translating research knowledge into policy is a complex and context sensitive process. Researchers aiming to enhance knowledge translation need to be aware of factors influencing the demand for different types of research; interact and work closely with key policy stakeholders, networks and local champions; and acknowledge the roles of important interest groups. [ABSTRACT FROM AUTHOR]

Spline curves are useful in a variety of geometric modeling and graphics applications and covering problems abound in practical settings. This work defines a class of covering decision problems for shapes bounded by spline curves. As a first step in addressing these problems, this paper treats translational spline covering for planar, uniform, cubic B-splines. Inner and outer polygonal approximations to the spline regions are generated using enclosures that are inside two different types of piecewise-linear envelopes. Our recent polygonal covering technique is then applied to seek translations of the covering shapes that allow them to fully cover the target shape. A feasible solution to the polygonal instance provides a feasible solution to the spline instance. We use our recent proof that 2D translational polygonal covering is NP-hard to establish NP-hardness of our planar translational spline covering problem. Our polygonal approximation strategy creates approximations that are tight, yet the number of vertices is only a linear function of the number of control points. Using recent results on B-spline curve envelopes, we bound the distance from the spline curve to its approximation. We balance the two competing objectives of tightness vs. number of points in the approximation, which is crucial given the NP-hardness of the spline problem. Examples of the results of our spline covering work are provided for instances containing as many as six covering shapes, including both convex and nonconvex regions. Our implementation uses the LEDA and CGAL C++ libraries of geometric data structures and algorithms. [ABSTRACT FROM AUTHOR]

We present experimental evidence that the motion of point defects in thermal convection patterns in an inclined fluid layer is well described by Tsallis statistics with an entropic index q≈1.5. The dynamical properties of the defects (anomalous diffusion, shape of velocity distributions, power-law decay of correlations) are in good agreement with typical predictions of nonextensive models, over a range of driving parameters. [Copyright &y& Elsevier]

We report experiments on defect-tracking in the state of undulation chaos observed in thermal convection of an inclined fluid layer. We characterize the ensemble of defect trajectories according to their velocities, relative positions, diffusion, and gain and loss rates. In particular, the defects exhibit incidents of rapid transverse motion which result in power law distributions for a number of quantitative measures. We examine connections between this behavior and Lévy flights and anomalous diffusion. In addition, we describe time-reversal and system size invariance for defect creation and annihilation rates. [ABSTRACT FROM AUTHOR]

Interviews May Rosalind Santon, a long-time resident of the middle-class community of Claremont in Cape Town, South Africa. Account of the relocation of blacks from the community in the 1970s; Insight into the process of memory and making of 'evidence'; Revelation of Santon's 'respectability'; Pervasive presence of respectability in colored enclaves.

When in a pristine state, gallium and its alloys have the largest interfacial tensions of any liquid at room temperature. Nonetheless, applying as little as 0.8 V of electric potential across eutectic gallium indium (EGaIn) placed within aqueous sodium hydroxide (NaOH, or other electrolyte) solution will cause the metal to behave as if its interfacial tension is near zero. The mechanism behind this phenomenon has remained poorly understood because NaOH dissolves the oxide species, making it difficult to directly measure the concentration, thickness, or chemical composition of the film that forms at the interface. In addition, the oxide layers formed are atomically‐thin. Here, it presents a suite of techniques that allow to simultaneously measure both electrical and interfacial properties as a function of applied electric potential, allowing for new insights into the mechanisms, which cause the dramatic decrease in interfacial tension. A key discovery from this work is that the interfacial tension displays hysteresis while lowering the applied potential. It combines these observations with electrochemical impedance spectroscopy to evaluate how these changes in interfacial tension arise from chemical, electrical, and mechanical changes on the interface, and close with ideas for how to build a free energy model to predict these changes from first principles. [ABSTRACT FROM AUTHOR]

A trim placement problem from the apparel industry is presented and solved. The problem is related to cutting and packing problems, which have received attention in the literature for close to 40 years. The problem is motivated by a pants layout problem involving irregularly-shaped pieces. A two-stage strategy is commonly employed, with large pieces, or panels, arranged first, followed by smaller pieces, or trim. This paper assumes the panels have been arranged, and presents an approach for placing the trim pieces into unused "containers" of the stock material. Groups of trim pieces are first generated using existing polygon containment algorithms. Then, groups are assigned to containers to maximize a weighted function of the trim pieces. The mathematical programming formulation is developed, which is a generalization of the Maximum Cover Problem, a well-known problem in the location literature. Due to wide variability in branch and bound solution times, a Lagrangian Heuristic incorporating an improvement heuristic is developed. Computational experience demonstrates the effectiveness of the Lagrangian Heuristic on real pants markers. The optimal solution is found for all, and solution times are less than branch and bound in 10 out of 12 problem instances (considerably less in three), and only slightly more in the other two. Times are also less variable than branch and bound, an important characteristic with an interactive layout system. [ABSTRACT FROM AUTHOR]

Ordinary fluids mix themselves through thermal motions, or can be even more efficiently mixed by stirring. In contrast, granular materials such as sand often unmix when they are stirred, shaken or sheared. This granular segregation is both a practical means to separate materials in industry, and a persistent challenge to uniformly mixing them. While segregation phenomena are ubiquitous, a large number of different mechanisms have been identified and the underlying physics remains the subject of much inquiry. Particle size, shape, density and even surface roughness can play significant roles. The aim of this focus issue is to provide a snapshot of the current state of the science, covering a wide range of packing densities and driving mechanisms, from thermal-like dilute systems to dense flows. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue, including one on a real-world two-dimensional guillotine cutting stock problem which cuts out buns in a cake production environment, another on a novel non-linear optimization-based approach to the minimal area rectangular packing problem, as well as a report on testing two genetic algorithms inspired by molecular genetics on two packing problems.