Local field topology behind light localization and metamaterial topological transitions

We revisit the mechanisms governing the sub-wavelength spatial localization of light in surface plasmon polariton (SPP) modes by investigating both local and global features in optical powerflow at SPP frequencies. Close inspection of the instantaneous Poynting vector reveals formation of optical vortices - localized areas of cyclic powerflow - at the metal-dielectric interface. As a result, optical energy circulates through a subwavelength-thick 'conveyor belt' between the metal and dielectric where it creates a high density of optical states (DOS), tight optical energy localization, and low group velocity associated with SPP waves. The formation of bonding and anti-bonding SPP modes in metal-dielectric-metal waveguides can also be conveniently explained in terms of different spatial arrangements of localized powerflow vortices between two metal interfaces. Finally, we investigate the underlying mechanisms of global topological transitions in metamaterials composed of multiple metal and dielectric films, i.e., transitions of their iso-frequency surfaces from ellipsoids to hyperboloids, which are not accompanied by the breaking of lattice symmetry. Our analysis reveals that such global topological transitions are governed by the dynamic local re-arrangement of local topological features of the optical interference field, such as vortices and saddle points, which reconfigures global optical powerflow within the metamaterial. These new insights into plasmonic light localization and DOS manipulation not only help to explain the well-known properties of SPP waves but also provide useful guidelines for the design of plasmonic components and materials for a variety of practical applications.Comment: 25 pages, 9 figures, Ch. 8 of Singular and Chiral Nanoplasmonics (S.V. Boriskina and N.I. Zheludev Eds.) Pan Stanford, Singapore, 201

Bed Material Sampling Error in Sand Bed Rivers

A total of 468 bed material samples were collected at cross sections of the sand bed of the South Saskatchewan River at Saskatoon to assess the random and systematic errors in the results from four commonly used samplers. Statistically significant differences in particle size distribution occur between the results obtained from different samplers at the same location, in part due to variability in retention of the small particles. The differences are greatest in silty sand and least in well-sorted, medium sand. The precision of results from repetitive samples at the same location using the same sampler depends on both the sampler and the composition of the bed material. Except in well-sorted, medium sand, a single sample at a vertical is inadequate to determine the particle size of a given size fraction to within 10% with a probability of error of 0.1. In some cases 10 or more samples may be required. The magnitude of these statistical errors at a given location is generally less than the within-reach variability in bed material particle size, and therefore the appropriate choice of sample location is critical

Imprisonment and internment: Comparing penal facilities North and South

Recent references to the ‘warehouse prison’ in the United States and the prisión-depósito in Latin America seem to indicate that penal confinement in the western hemisphere has converged on a similar model. However, this article suggests otherwise. It contrasts penal facilities in North America and Latin America in terms of six interrelated aspects: regimentation; surveillance; isolation; supervision; accountability; and formalization. Quantitatively, control in North American penal facilities is assiduous (unceasing, persistent and intrusive), while in Latin America it is perfunctory (sporadic, indifferent and cursory). Qualitatively, North American penal facilities produce imprisonment (which enacts penal intervention through confinement), while in Latin America they produce internment (which enacts penal intervention through release). Closely entwined with this qualitative difference are distinct practices of judicial involvement in sentencing and penal supervision. Those practices, and the cultural and political factors that underpin them, represent an interesting starting point for the explanation of the contrasting nature of imprisonment and internment

Web Vulnerability Study of Online Pharmacy Sites

Consumers are increasingly using online pharmacies, but these sites may not provide an adequate level of security with the consumers’ personal data. There is a gap in this research addressing the problems of security vulnerabilities in this industry. The objective is to identify the level of web application security vulnerabilities in online pharmacies and the common types of flaws, thus expanding on prior studies. Technical, managerial and legal recommendations on how to mitigate security issues are presented. The proposed four-step method first consists of choosing an online testing tool. The next steps involve choosing a list of 60 online pharmacy sites to test, and then running the software analysis to compile a list of flaws. Finally, an in-depth analysis is performed on the types of web application vulnerabilities. The majority of sites had serious vulnerabilities, with the majority of flaws being cross-site scripting or old versions of software that have not been updated. A method is proposed for the securing of web pharmacy sites, using a multi-phased approach of technical and managerial techniques together with a thorough understanding of national legal requirements for securing systems

An epistemic community comes and goes? Local and national expressions of heart health promotion in Canada

<p>Abstract</p> <p>Background</p> <p>The objective of this study is to examine the existence and shape of epistemic communities for (heart) health promotion at the international, national, provincial and regional levels in Canada. Epistemic community may be defined as a network of experts with an authoritative claim to policy relevant knowledge in their area of expertise.</p> <p>Methods</p> <p>An interpretive policy analysis was employed using 60 documents (48 provincial, 8 national and 4 international) and 66 interviews (from 5 Canadian provinces). These data were entered into NUD*IST, a qualitative software analysis package, to assist in the development of codes and themes. These codes form the basis of the results.</p> <p>Results</p> <p>A scientific and policy epistemic community was identified at the international and Canadian federal levels. Provincially and regionally, the community is present as an idea but its implementation varies between jurisdictions.</p> <p>Conclusion</p> <p>The importance of economic, political and cultural factors shapes the presence and shape of the epistemic community in different jurisdictions. The community waxes and wanes but appears robust.</p

The status of women police officers: an international review

This paper reports on a survey of English-language police department websites, annual reports and other reports in order to identify key aspects of the status of women police internationally. Findings are reported for England and Wales, Scotland, Northern Ireland, Eire, the United States, Canada, Australia (eight departments), New Zealand, South Africa, Ghana, Nigeria, India, Pakistan, Hong Kong, Papua New Guinea, and Fiji. Data on the proportion of female officers were available from 18 of 23 locations, with a range between 5.1% and 28.8%. Recruit numbers were available for six locations, and ranged between 26.6% and 37.0%. Limited data on rank and deployment indicated overall improvements. Available longer-term trend data suggested that growth in female officers was slowing or levelling out. Overall, the study showed an urgent need to improve gender-based statistics in order to better inform strategies aimed at maximising the participation of women in policing