Making waves round a structured cloak: lattices, negative refraction and fringes

Using the framework of transformation optics, this paper presents a detailed analysis of a non-singular square cloak for acoustic, out-of-plane shear elastic and electromagnetic waves. Analysis of wave propagation through the cloak is presented and accompanied by numerical illustrations. The efficacy of the regularized cloak is demonstrated and an objective numerical measure of the quality of the cloaking effect is provided. It is demonstrated that the cloaking effect persists over a wide range of frequencies. As a demonstration of the effectiveness of the regularized cloak, a Young’s double slit experiment is presented. The stability of the interference pattern is examined when a cloaked and uncloaked obstacle are successively placed in front of one of the apertures. This novel link with a well-known quantum mechanical experiment provides an additional method through which the quality of cloaks may be examined. In the second half of the paper, it is shown that an approximate cloak may be constructed using a discrete lattice structure. The efficiency of the approximate lattice cloak is analysed and a series of illustrative simulations presented. It is demonstrated that effective cloaking may be obtained by using a relatively simple lattice structure, particularly, in the low-frequency regime

Two Bee-Pollinated Plant Species Show Higher Seed Production when Grown in Gardens Compared to Arable Farmland

Background Insect pollinator abundance, in particular that of bees, has been shown to be high where there is a super-abundance of floral resources; for example in association with mass-flowering crops and also in gardens where flowering plants are often densely planted. Since land management affects pollinator numbers, it is also likely to affect the resultant pollination of plants growing in these habitats. We hypothesised that the seed or fruit set of two plant species, typically pollinated by bumblebees and/or honeybees might respond in one of two ways: 1) pollination success could be reduced when growing in a floriferous environment, via competition for pollinators, or 2) pollination success could be enhanced because of increased pollinator abundance in the vicinity. Methodology/Principal Findings We compared the pollination success of experimental plants of Glechoma hederacea L. and Lotus corniculatus L. growing in gardens and arable farmland. On the farms, the plants were placed either next to a mass-flowering crop (oilseed rape, Brassica napus L. or field beans, Vicia faba L.) or next to a cereal crop (wheat, Triticum spp.). Seed set of G. hederacea and fruit set of L. corniculatus were significantly higher in gardens compared to arable farmland. There was no significant difference in pollination success of G. hederacea when grown next to different crops, but for L. corniculatus, fruit set was higher in the plants growing next to oilseed rape when the crop was in flower. Conclusions/Significance The results show that pollination services can limit fruit set of wild plants in arable farmland, but there is some evidence that the presence of a flowering crop can facilitate their pollination (depending on species and season). We have also demonstrated that gardens are not only beneficial to pollinators, but also to the process of pollination

A new model for health care delivery

<p>Abstract</p> <p>Background</p> <p>The health care delivery system in the United States is facing cost and quality pressures that will require fundamental changes to remain viable. The optimal structures of the relationships between the hospital, medical school, and physicians have not been determined but are likely to have a large impact on the future of healthcare delivery. Because it is generally agreed that academic medical centers will play a role in the sustainability of this future system, a fundamental understanding of the relative contributions of the stakeholders is important as well as creativity in developing novel strategies to achieve a shared vision.</p> <p>Discussion</p> <p>Core competencies of each of the stakeholders (the hospital, the medical school and the physicians) must complement the others and should act synergistically. At the same time, the stakeholders should determine the common core values and should be able to make a meaningful contribution to the delivery of health care.</p> <p>Summary</p> <p>Health care needs to achieve higher quality and lower cost. Therefore, in order for physicians, medical schools, and hospitals to serve the needs of society in a gratifying way, there will need to be change. There needs to be more scientific and social advances. It is obvious that there is a real and urgent need for relationship building among the professionals whose duty it is to provide these services.</p

Estimating the Diets of Animals Using Stable Isotopes and a Comprehensive Bayesian Mixing Model

Using stable isotope mixing models (SIMMs) as a tool to investigate the foraging ecology of animals is gaining popularity among researchers. As a result, statistical methods are rapidly evolving and numerous models have been produced to estimate the diets of animals—each with their benefits and their limitations. Deciding which SIMM to use is contingent on factors such as the consumer of interest, its food sources, sample size, the familiarity a user has with a particular framework for statistical analysis, or the level of inference the researcher desires to make (e.g., population- or individual-level). In this paper, we provide a review of commonly used SIMM models and describe a comprehensive SIMM that includes all features commonly used in SIMM analysis and two new features. We used data collected in Yosemite National Park to demonstrate IsotopeR's ability to estimate dietary parameters. We then examined the importance of each feature in the model and compared our results to inferences from commonly used SIMMs. IsotopeR's user interface (in R) will provide researchers a user-friendly tool for SIMM analysis. The model is also applicable for use in paleontology, archaeology, and forensic studies as well as estimating pollution inputs

Changing Bee and Hoverfly Pollinator Assemblages along an Urban-Rural Gradient

The potential for reduced pollination ecosystem service due to global declines of bees and other pollinators is cause for considerable concern. Habitat degradation, destruction and fragmentation due to agricultural intensification have historically been the main causes of this pollinator decline. However, despite increasing and accelerating levels of global urbanization, very little research has investigated the effects of urbanization on pollinator assemblages. We assessed changes in the diversity, abundance and species composition of bee and hoverfly pollinator assemblages in urban, suburban, and rural sites across a UK city.Bees and hoverflies were trapped and netted at 24 sites of similar habitat character (churchyards and cemeteries) that varied in position along a gradient of urbanization. Local habitat quality (altitude, shelter from wind, diversity and abundance of flowers), and the broader-scale degree of urbanization (e.g. percentage of built landscape and gardens within 100 m, 250 m, 500 m, 1 km, and 2.5 km of the site) were assessed for each study site. The diversity and abundance of pollinators were both significantly negatively associated with higher levels of urbanization. Assemblage composition changed along the urbanization gradient with some species positively associated with urban and suburban land-use, but more species negatively so. Pollinator assemblages were positively affected by good site habitat quality, in particular the availability of flowering plants.Our results show that urban areas can support diverse pollinator assemblages, but that this capacity is strongly affected by local habitat quality. Nonetheless, in both urban and suburban areas of the city the assemblages had fewer individuals and lower diversity than similar rural habitats. The unique development histories of different urban areas, and the difficulty of assessing mobile pollinator assemblages in just part of their range, mean that complementary studies in different cities and urban habitats are required to discover if these findings are more widely applicable

A falling of the veils: turning points and momentous turning points in leadership and the creation of CSR

This article uses the life stories approach to leadership and leadership development. Using exploratory, qualitative data from a Forbes Global 2000 and FTSE 100 company, we discuss the role of the turning point (TP) as an important antecedent of leadership in corporate social responsibility. We argue that TPs are causally efficacious, linking them to the development of life narratives concerned with an evolving sense of personal identity. Using both a multi-disciplinary perspective and a multi-level focus on CSR leadership, we identify four narrative cases. We propose that they helped to re-define individuals’ sense of self and in some extreme cases completely transformed their self-identity as leaders of CSR. Hence we also distinguish the momentous turning point (MTP) that created a seismic shift in personality, through re-evaluation of the individuals’ personal values. We argue that whilst TPs are developmental experiences that can produce responsible leadership, the MTP changes the individuals’ personal priorities in life to produce responsible leadership that perhaps did not exist previously. Thus we appropriate Maslow’s (1976, p. 77) metaphorical phrase ‘A falling of the veils’ from his discussion of peak and desolation experiences that produce personal growth. Using a multi-disciplinary literature from social theory (Archer, 2012) moral psychology (Narvaez, 2009) and social psychology (Schwartz, 2010), we present a theoretical model that illustrates the psychological process of the (M)TP, thus contributing to the growing literature on the microfoundations of CSR

Challenges in improving access to Asian laws: the Asian Legal Information Institute (AsianLII)

This article discusses the challenges involved in building the Asian Legal Information Institute (AsianLII), a free access legal research facility developed by the Australian Legal Information Institute - AustLII - in conjunction with partners in various Asian countries. The focus is on dealing with a region of such linguistic diversity and on the rationale and technical features of AsianLII as well as issues of approaches to partnerships, migration of technology and content control, and sustainability. The article explains that, while the data aggregation on which AsianLII is based has been assisted by the copyright laws of the region and by a centralised approach, the sustainability of AsianLII depends on partnerships and decentralisation. Similarly, while English language materials have been the best startingpoint to develop the system, a multi-bilingual approach will be necessary for its longer term development

Searching Legal Information in Multiple Asian Languages

In this article Philip Chung, Andrew Mowbray, and Graham Greenleaf, the Co-Directors of the Australasian Legal Information Institute (AustLII), explain the need for an open source search engine which can search simultaneously over legal materials in European languages and also in Asian languages, particularly those that require a `double byte representation, and the difficulties this task presents. A solution is proposed; the `u16a modifications to AustLIIs open source search engine (Sino) which is used by many legal information institutes. Two implementations of the Sino u16A approach, on the Hong Kong Legal Information Institute (HKLII), for English and Chinese, and on the Asian Legal Information Institute (AsianLII), for multiple Asian languages, are described. The implementations have been successful, though many challenges (discussed briefly) remain before this approach will provide a full multi-lingual search facility