Experimental Observation of Modulation Instability and Optical Spatial Soliton Arrays in Soft Condensed Matter

In this Letter we report observations of optically induced self-organization of colloidal arrays in the presence of un-patterned counter-propagating evanescent waves. The colloidal arrays formed along the laser propagation-axis are shown to be linked to the break-up of the incident field into optical spatial solitons, the lateral spacing of the arrays being related to modulation instability of the soft condensed matter system.Comment: 16 pages, 3 figure

Superconducting Surface Impedance under Radiofrequency Field

Based on BCS theory with moving Cooper pairs, the electron states distribution at 0K and the probability of electron occupation with finite temperature have been derived and applied to anomalous skin effect theory to obtain the surface impedance of a superconductor under radiofrequency (RF) field. We present the numerical results for Nb and compare these with representative RF field-dependent effective surface resistance measurements from a 1.5 GHz resonant structure

Development of a static bioactive stent prototype and dynamic aneurysm-on-a-chip(TM) model for the treatment of aneurysms

Aneurysms are pockets of blood that collect outside blood vessel walls forming dilatations and leaving arterial walls very prone to rupture. Current treatments include: (1) clipping, and (2) coil embolization, including stent-assisted coiling. While these procedures can be effective, it would be advantageous to design a biologically active stent, modified with magnetic stent coatings, allowing cells to be manipulated to heal the arterial lining. Further, velocity, pressure, and wall shear stresses aid in the disease development of aneurysmal growth, but the shear force mechanisms effecting wound closure is elusive. Due to these factors, there is a definite need to cultivate a new stent device that will aid in healing an aneurysm insitu. To this end, a static bioactive stent device was synthesized. Additionally, to study aneurysm pathogenesis, a lab-on-a-chip device (a dynamic stent device) is the key to discovering the underlying mechanisms of these lesions. A first step to the reality of a true bioactive stent involves the study of cells that can be tested against the biomaterials that constitute the stent itself. The second step is to test particles/cells in a microfluidic environment. Therefore, biocompatability data was collected against PDMS, bacterial nanocellulose (BNC), and magnetic bacterial nanocellulose (MBNC). Preliminary static bioactive stents were synthesized whereby BNC was grown to cover standard nitinol stents. In an offshoot of the original research, a two-dimensional microfluidic model, the Aneurysm-on-a-ChipTM (AOC), was the logical answer to study particle flow within an aneurysm sac - this was the dynamic bioactive stent device. The AOC apparatus can track particles/cells when it is coupled to a particle image velocimetry software (PIV) package. The AOC fluid flow was visualized using standard microscopy techniques with commercial microparticles/cells. Movies were taken during fluid flow experiments and PIV was utilized to monito

Pandemic Kinship

Shaped around the stories of one extended family, their friends, neighbours and community, this offers an intimate portrait of everyday life in Botswana's time of AIDS. It tackles questions relevant to scholars and practitioners of anthropology, public health, social work, and development. This title is available Open Access on Cambridge Core

Investigating the evolution of apoptosis in malaria parasites: the importance of ecology

Apoptosis is a precisely regulated process of cell death which occurs widely in multicellular organisms and is essential for normal development and immune defences. In recent years, interest has grown in the occurrence of apoptosis in unicellular organisms. In particular, as apoptosis has been reported in a wide range of species, including protozoan malaria parasites and trypanosomes, it may provide a novel target for intervention. However, it is important to understand when and why parasites employ an apoptosis strategy before the likely long-and short-term success of such an intervention can be evaluated. The occurrence of apoptosis in unicellular parasites provides a challenge for evolutionary theory to explain as organisms are expected to have evolved to maximise their own proliferation, not death. One possible explanation is that protozoan parasites undergo apoptosis in order to gain a group benefit from controlling their density as this prevents premature vector mortality. However, experimental manipulations to examine the ultimate causes behind apoptosis in parasites are lacking. In this review, we focus on malaria parasites to outline how an evolutionary framework can help make predictions about the ecological circumstances under which apoptosis could evolve. We then highlight the ecological considerations that should be taken into account when designing evolutionary experiments involving markers of cell death, and we call for collaboration between researchers in different fields to identify and develop appropriate markers in reference to parasite ecology and to resolve debates on terminology.Host-parasite interactio

The School Head as an Instructional Leader in Zimbabwe Secondary Schools

A Zimbabwe Journal of Educational Research (ZJER) article.This paper presents evidence obtained from a survey of secondary school heads in government schools, church schools, and rural day schools about functions performed by those heads, characteristics of secondary school heads and problems constraining heads from discharging their duties effectively and efficiently. The evidence shows that: 1. The majority of rural secondary schools are administered by inexperienced and lowly qualified and untrained heads who also' have heavy teaching loads. 2. The majority of school heads possess minimal or no knowledge in technical subjects, a situation which appears not supportive of the implementation of the policy of vocationalization of secondary school education. 3. While the thrust in secondary school education is on technical education, school heads do not consider the training of students in technical fields as a top priority for secondary schools. To the contrary, heads consider character building and preparation for post-secondary programmes as top priorities for secondary schools. 4. Secondary school heads devote most of their time on administrative duties thereby neglecting the critical activities in the curriculum and instructional domains

The relationship of strategy, fit, productivity, and business performance in a services setting

In their review of the operations strategy literature, Anderson et al. [Anderson, J.C., Cleveland, G., Schroeder, R.G., 1989. Operations strategy: a literature review. J. Operations Manage., 8(2): 133‐158] contend that the hypothesis that a company will perform better if it links its operations strategy to the business strategy is intuitively appealing, but lacks empirical verification. In light of this contention, this research attempts to: (1) define and measure the concept of fit as it applies to operations strategy; (2) show how fit leads to better performance; and (3) investigate the interrelationships between fit, business strategy, productivity, and performance. These objectives are investigated through field‐based research within a wholesale distribution service setting. Utilizing the classificatory framework of Venkatraman [Venkatraman, N., 1989. The concept of fit in strategy research: toward verbal and statistical correspondence. Acad. Manage. Rev., 14(3): 423‐444], fit is defined as the degree to which operational elements match the business strategy. This precise definition closely resembles the concept of ‘external fit’ that began with the work of Skinner [Skinner, W., 1969. Manufacturing–missing link in corporate strategy. Harvard Bus. Rev., 47(3): 136‐145]. A conceptual model of business performance is used with productivity as a mediating variable between the independent variables of business strategy and external fit and the dependent variable of business performance. Path analysis is used to analyze the effect of external fit on performance and to investigate the interrelationships between fit, business strategy, productivity, and performance. The results show that external fit has a significant positive and direct effect on business performance. When coupled with the nonsignificant direct effects of the strategy variables, this suggests that the fit of the operational elements with the strategy is of greater importance than the particular choice of strategy. Although all three business strategies (low cost, a combination of low cost and high customer service, and high customer service) had no significant direct effects on performance, a high customer service strategy did have a significant positive effect on the intervening productivity variable. Finally, the particular design of the research and the findings suggest that much of the conceptual work in operations strategy may be applicable to service operations as well as manufacturing.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146853/1/joom145.pd

A Critical Literacy Approach to Student Affairs Education

This article argues for the use of critical literacy as a critical pedagogy in student affairs practice. The authors describe how some currents of the student affairs literature have shifted toward a focus on student learning and critical approaches to student development and learning. Subsequently, they discuss the social turn in our understanding of literacy and a related move toward critical approaches to understanding literacy as a social practice. Finally, they present a synthesis of the literature, which results in considerations for approaching higher education student affairs contexts through a critical literacy framework, exposing gaps and areas for future theorizing and research