On the action of - electrostatic alternators

A detailed analysis, based on a consideration of charges and potentials, is made of the action of two simple electrostatic alternators; a four-symmetric, four carrier, machine, and a trisymmetric, six carrier, machone.Each of the machines is the prototype of a whole family of polysymmetric electrostatic alternators, and the method of analysis is extended to the generalized machine of each type. A basis for a qualitative theory of electrostatic alternators is evolved.     

A bioecological perspective on talent identification in junior-elite soccer: A Pan-European perspective

ABSTRACT

Elite soccer clubs across Europe spend ever-increasing sums of money on transfers and salaries for world-class players. Consequently, clubs’ talent identification and development processes for junior players have become more professionalised. Based on a holistic ecological approach, this study presents an analysis of talent identification practices across some of the most productive soccer academies in Europe (N = 11). Data were collected via semi-structured interviews with 11 heads of academy recruitment from clubs in the “big five” European leagues. Clubs were purposively sampled based on their player productivity ranking. Interviews ranged from 52:26 minutes to 114:06 minutes in length (m = 87:53 ± 20.10 minutes). This study argues that holistic ecological approaches the environments were characterised through the interplay of factors that ranged from high-level internal to international level relationships. This resulted in the identification and recruitment of players from local and international environments. The purpose of recruitment was suggested to have a dual purpose: recruitment of players for the first team; recruitment of players for further development/monitoring and/or selling to another club.     

Reported school experiences of young people living with sickle cell disorder in England

A survey of 569 young people with sickle cell disorder (SCD) in England has found such pupils miss considerable periods of time from school, typically in short periods of two or three days. One in eight has school absences equating to government‐defined ‘persistent absence’. Students with SCD report that they are not helped to catch up after these school absences. Half the children reported not being allowed to use the toilet when needed and not being allowed water in class; a third reported being made to take unsuitable exercise and being called lazy when tired. Children perceived both physical environment (temperature, school furniture) and social environment (being upset by teachers or other pupils) as triggers to episodes of their illness. Policy initiatives on school absences; preventive measures to ensure maintenance of good health; and measures to prevent perceived social attitudes precipitating ill health would also support children with other chronic illnesses at school.     

Beyond aid effectiveness: The development of the South African further education and training college sector, 1994–2009

The current dominant account of aid to education focuses on schooling and official development assistance and talks in terms of policy work, donor harmonisation and, increasingly, budgetary support. However, this approach is limited in a number of ways. The return of international policy interest in vocational education provides an opportunity to take a look at whether the dominant paradigm is really a solution in all cases. Through an exploration of the evolution of the South African further education and training, this paper illustrates the importance of looking at where a country wants and does not want to learn from. It points to the need to gaze beyond official development assistance to examine the way that dimensions such as cultural diplomacy, commercial interests and solidarity play a role in policy learning. It also draws attention to the often-varied national institutional resources for learning and the complex interplay of individuals, both local and foreign, in the learning process. Finally, it hints that many apparently minor instruments such as exile, study abroad and structured exchange visits may contribute to a far more complex web of policy-related learning than is captured in conventional accounts of policy borrowing/learning that focus on the official level. It may be that a more meaningful discussion of the effectiveness of international cooperation, rather than the more narrow notion of aid, would ensue if such perspectives were taken on board.     

Experimental identification of social learning in wild animals

Field experiments can provide compelling demonstrations of social learning in wild populations. Social learning has been experimentally demonstrated in at least 23 field experiments, in 20 species, covering a range of contexts, such as foraging preferences and techniques, habitat choice, and predator avoidance. We review experimental approaches taken in the field and with wild animals brought into captivity and note how these approaches can be extended. Relocating individuals, introducing trained individual demonstrators or novel behaviors into a population, or providing demonstrator-manipulated artifacts can establish whether and how a particular act can be socially transmitted in the wild and can help elucidate the benefits of social learning. The type, strength, and consistency of presented social information can be varied, and the provision of conditions favoring the performance of an act can both establish individual discovery rates and help determine whether social information is needed for acquisition. By blocking particular avenues of social transmission or removing key individuals, routes of transmission in wild populations can be investigated. Manipulation of conditions proposed to favor social learning can test mathematical models of the evolution of social learning. We illustrate how field experiments are a viable, vital, and informative approach to the study of social learning.     

Novel on-demand droplet generation for selective fluid sample extraction

A novel microfluidic device enabling selective generation of droplets and encapsulation of targets is presented. Unlike conventional methods, the presented mechanism generates droplets with unique selectivity by utilizing a K-junction design. The K-junction is a modified version of the classic T-junction with an added leg that serves as the exit channel for waste. The dispersed phase fluid enters from one diagonal of the K and exits the other diagonal while the continuous phase travels in the straight leg of the K. The intersection forms an interface that allows the dispersed phase to be controllably injected through actuation of an elastomer membrane located above the inlet channel near the interface. We have characterized two critical components in controlling the droplet size-membrane actuation pressure and timing as well as identified the region of fluid in which the droplet will be formed. This scheme will have applications in fluid sampling processes and selective encapsulation of materials. Selective encapsulation of a single cell from the dispersed phase fluid is demonstrated as an example of functionality of this design.