Fourier Optics approach to imaging with sub-wavelength resolution through metal-dielectric multilayers

Metal-dielectric layered stacks for imaging with sub-wavelength resolution are regarded as linear isoplanatic systems - a concept popular in Fourier Optics and in scalar diffraction theory. In this context, a layered flat lens is a one-dimensional spatial filter characterised by the point spread function. However, depending on the model of the source, the definition of the point spread function for multilayers with sub-wavelength resolution may be formulated in several ways. Here, a distinction is made between a soft source and hard electric or magnetic sources. Each of these definitions leads to a different meaning of perfect imaging. It is shown that some simple interpretations of the PSF, such as the relation of its width to the resolution of the imaging system are ambiguous for the multilayers with sub-wavelenth resolution. These differences must be observed in point spread function engineering of layered systems with sub-wavelength sized PSF

Habitat associations and natural history of the Tasmanian "snow skinks" (Niveoscincus spp.)

Niveoscincus "snow skink" is the largest genus of lizards in Tasmania, but little literature is available on the ecology of the seven species discussed here. They were examined by studying the vegetation associations and natural history of all Niveoscincus species except N palfreymani. Most were found to be primarily either ground-dwelling, saxicolous or arboreal, although a few species, such as N microlepidotus, showed a combination of these habits. Saxicolous and heath/rock-dwelling species were restricted to more open habitats. Ground-dwelling species, on the other hand, were widespread and found in many different habitats but not in open rocky areas. Arboreal species were found in a wide range of forest habitats from sea-level to the tree line. The species studied were found to have significantly different, although partially overlapping habitat preferences

The Board of Directors and Firm Performance: Empirical Evidence from Listed Companies

Purpose: This study seeks to reconcile some of the conflicting results in prior studies of the board structure/firm performance relationship, and to evaluate the effectiveness and applicability of agency theory in the specific context of Italian corporate governance practice. Design/methodology/approach: This research applies a dynamic Generalized Method of Moments (GMM) methodology on a sample of Italian listed companies over the period 2003-2015. Proxies for corporate governance mechanisms are the board size, the level of board independence, ownership structure, shareholder agreements and CEO-Chairman leadership. Findings: While directors elected by minority shareholders are not able to impact upon performance, independent directors do have a non-linear effect on performance. Board size has a positive effect on firm performance for lower levels of board size. Ownership structure per se and shareholder agreements do not affect firm performance. Research Implications: This paper contributes to the literature on agency theory by reconciling some of the conflicting results inherent in the board structure-performance relationship. Firm performance is not necessarily improved by having a high number of independent directors on the board. Ownership structure and composition do not affect firm performance; therefore, greater monitoring provided by concentrated ownership does not necessarily lead to stronger firm performance. Practical Implications: We suggest that Italian corporate governance law should improve the rules and effectiveness of minority directors by controlling whether they are able to impede the main shareholders to expropriate private benefits on the expenses of the minority. The legislator should not impose any restrictive regulations with regard to CEO-duality, as the influence of CEO-duality on performance may vary with respect to the unique characteristics of each company. Originality/Value: The results enrich the understanding of the applicability of agency theory in listed companies, especially in Italy. Additionally, this paper provides a comprehensive synthesis of research evidence of agency theory studies

People centric governance model: Conceptualizing the pillars of significance

This article explores corporate governance issue from the perspective of peoples’ governance. Using qualitative research approach, specifically, a grounded theory method, the paper explores the role of the pillar of significance in corporate governance practices. Interview was used as primary data, although document was also analysed. Analysis of the data revealed people centric governance is essential. Findings suggest that there are several pillar of significance in the corporations that provide strength to the corporate governance practices. Emerging theory suggests that the core of corporate governance lies on the people rather that the structure. The finding is useful as it impacted governance problem in such a way that the findings provides information that would enhance governance effectiveness in corporations. This study unlocked the perception that corporate governance flaws relate with corporate governance structure. This article offers originality and new insights in understudy of governance concept that commonly relate with economic perspective

A qualitative study exploring why adults with intellectual disabilities and obesity want to lose weight and views of their carers

Background: Obesity is more prevalent in adults with intellectual disabilities (ID) compared to the general population. Motivations for weight loss may influence engagement with weight management programmes and have only been studied in adults without ID. Aims: To determine reasons given by adults with ID and obesity for seeking weight loss and whether these reasons differ from those of their carers. Methods: Prior to a multi-component weight management intervention, participants were asked “why do you want to lose weight?” Carers were asked their views and these were compared to the answers given by the adult with ID. Responses were themed. The Fisher’s Exact analysis was used to test for any relationship between reasons for seeking weight loss and participants’ level of ID, age, gender and BMI. Results: Eighteen men and 32 women; age 41.6 SD 14.6 years; BMI 40.8 SD 7.5 kg/m2; Level ID Mild (28 %), Moderate (42 %), Severe (22 %), Profound (8 %). Eleven were unable to respond. Six themes emerged; Health; Fitness / Activity / Mobility; Appearance / Clothes; Emotional / Happiness; For Others; Miscellaneous. The most frequent reason given overall and by women was “appearance.” Carers cited “health” most frequently and “appearance” least, rarely agreeing with participants. “Health” was given as a reason more from older adults and those with milder ID. No statistically significant associations were found between reasons for seeking weight loss and BMI age, gender or level of ID but the differing views of adults with ID and their carers were clear. Conclusions: Views of adults with obesity and mild or moderate ID can be collected. The opposing views of adults and their carers may affect motivation for weight loss

Piston Airplane Cruise Performance

Ability to achieve efficient range and endurance performance can mean the difference between an uneventful flight and one which ends in anxiety or even tragedy. Beyond the economics of fuel costs, the presence of unexpectedly strong headwinds, navigational error, or deteriorating weather may test the pilot\u27s cruise management capability. The prudent pilot will be prepared by thoroughly understanding the principles underlying cruise performance

Application of a simulator for short term forecasting in a high volume multi-product production line

The solutions to the problems of production forecasting, scheduling, and in-process inventory control for high volume multi-product manufacturing lines are not readily available in current industrial literature. This study proposes simulation as a general approach to solving these problems and proceeds to develop a simulator which is applied to just such a high volume line

Sustainability of the Western Rock Lobster Fishery: A review of past progress and future challenges

The Western Rock (spiny) Lobster Fishery has 594 boats operating about 57,000 pots. The average annual catch of 11,000 tonnes is valued at around US$150 million. In addition to the commercial catch, recreational fishers take about 600 tonnes a year. Sustainability in this fishery is maintained by analysis of a comprehensive fisheries database, some of which dates back to the 1960s (e.g. catch, effort, length-frequencies, fishery-independent breeding-stock surveys, puerulus settlement monitoring, recreational catch monitoring); an extensive set of management controls (including a limited fishing season and legal minimum and maximum sizes); and an effective compliance program. Effort in the fishery is controlled by input restrictions on the number of pots allowed and number of days fishing, which are implemented after considerable consultation with industry. The principal method of ensuring the sustainability of the fishery is by monitoring the size of the breeding stock, using data from both a commercial at-sea monitoring program and an annual fishery-independent breeding-stock survey. When the breeding stock fell to low levels in the early 1990s, management initiatives succeeded in returning it to what are considered to be safe levels. Catches are currently high, but fishers have acquired sufficient scientific knowledge to understand that catches will fluctuate for environmental reasons and to take this into account in their fishing operations. Environmental effects have been shown to drive the level of settlement in a particular season. These settlement levels are in turn highly correlated with catches three to four years later, which provides a means of predicting future catches and managing the fishery accordingly. There are issues to be considered in assessing the sustainability of this fishery in the future. The fishery may be overly reliant on egg production from the Abrolhos Islands; catching power of the commercial fleet is increasing due to improvements in gear and technological equipment; growth in catches made by the recreational sector are currently unconstrained; pueruli may be harvested for aquaculture in the near future; and regulations protecting the female brood stock more than the male population could lead to reproductive issues. These potential threats are considered to be low, but will need to be monitored. The fishery was awarded Marine Stewardship Council certification in March 2000, the first in the world to receive this imprimatur