131 research outputs found
On the connection between mutually unbiased bases and orthogonal Latin squares
We offer a piece of evidence that the problems of finding the number of
mutually unbiased bases (MUB) and mutually orthogonal Latin squares (MOLS)
might not be equivalent. We study a particular procedure which has been shown
to relate the two problems and generates complete sets of MUBs in
power-of-prime dimensions and three MUBs in dimension six. For these cases,
every square from an augmented set of MOLS has a corresponding MUB. We show
that this no longer holds for certain composite dimensions.Comment: 6 pages, submitted to Proceedings of CEWQO 200
Mutually unbiased bases, orthogonal Latin squares, and hidden-variable models
Mutually unbiased bases encapsulate the concept of complementarity - the
impossibility of simultaneous knowledge of certain observables - in the
formalism of quantum theory. Although this concept is at the heart of quantum
mechanics, the number of these bases is unknown except for systems of dimension
being a power of a prime. We develop the relation between this physical problem
and the mathematical problem of finding the number of mutually orthogonal Latin
squares. We derive in a simple way all known results about the unbiased bases,
find their lower number, and disprove the existence of certain forms of the
bases in dimensions different than power of a prime. Using the Latin squares,
we construct hidden-variable models which efficiently simulate results of
complementary quantum measurements.Comment: Published versio
Ricardo flies Ryanair: Strategic human resource management and competitive advantage in a Single European Aviation Market
How and why are some firms, such as Ryanair, able to consistently record industry-leading profitability that sustains a competitive advantage over their rivals? HRM plays a critical role in four widely recognised profit-generating mechanisms, albeit not always in ways predicted by mainstream strategic HRM. Studies of HRMperformance grounded in the resource-based view (RBV) of the firm invariably focus on the human resources already controlled by the firm – specifically, resources that are rare, inimitable, non-substitutable and can be exploited through organisation (RINO) – rather than strategic factor markets (SFMs) where firms acquire their human resources. In doing so, these studies overlook the industrial relations and wider institutional context that might variously promote, permit or preclude particular HR policies and practices. It is only when different profit-generating mechanisms, either in isolation or combination, are activated under the auspicious conditions of a particular time and place that HRM contributes to sustained competitive advantage
Affine Constellations Without Mutually Unbiased Counterparts
It has been conjectured that a complete set of mutually unbiased bases in a
space of dimension d exists if and only if there is an affine plane of order d.
We introduce affine constellations and compare their existence properties with
those of mutually unbiased constellations, mostly in dimension six. The
observed discrepancies make a deeper relation between the two existence
problems unlikely.Comment: 8 page
Effects of Protein Deficiency on Perinatal and Postnatal Health Outcomes
There are a variety of environmental insults that can occur during pregnancy which cause low birth weight and poor fetal health outcomes. One such insult is maternal malnutrition, which can be further narrowed down to a low protein diet during gestation. Studies show that perinatal protein deficiencies can impair proper organ growth and development, leading to long-term metabolic dysfunction. Understanding the molecular mechanisms that underlie how this deficiency leads to adverse developmental outcomes is essential for establishing better therapeuticstrategies that may alleviate or prevent diseases in later life. This chapter reviews how perinatal protein restriction in humans and animals leads to metabolic disease, and it identifies the mechanisms that have been elucidated, to date. These include alterations in transcriptional and epigenetic mechanisms, as well as indirect means such as endoplasmic reticulum (ER) stress and oxidative stress. Furthermore, nutritional and pharmaceutical interventions are highlighted to illustrate that the plasticity of the underdeveloped organs during perinatal life can be exploited to prevent onset of long-term metabolic disease
International students and further education colleges in England: The context, policy tensions, and some aspects of practice
This chapter sets out the context of publicly funded further education colleges in England, outlining the position and development of these complex institutions within the broader educational structure. This is followed by discussion of some tensions and contradictions which arise from government policies partially driven by anxieties derived from debates surrounding levels of immigration together with recognition of the imperatives and opportunities arising from globalisation. The benefits of the internationalisation of education have been expounded whilst simultaneously enforcing visa regulations which impede the efforts of colleges to make inroads in the international student market. In particular, disparities between the treatment of the further and higher education sectors are highlighted. The paper also provides an account of practices which have emerged in a single FE college in England over a decade of working with international students following an access to HE course. The chapter indicates some of the many benefits which have been brought to FE by international students as well as the ways in which a college has developed its practices in response to their needs
Corporate philanthropy, political influence, and health policy
Background The Framework Convention of Tobacco Control (FCTC) provides a basis for nation states to limit the political effects of tobacco industry philanthropy, yet progress in this area is limited. This paper aims to integrate the findings of previous studies on tobacco industry philanthropy with a new analysis of British American Tobacco's (BAT) record of charitable giving to develop a general model of corporate political philanthropy that can be used to facilitate implementation of the FCTC. Method Analysis of previously confidential industry documents, BAT social and stakeholder dialogue reports, and existing tobacco industry document studies on philanthropy. Results The analysis identified six broad ways in which tobacco companies have used philanthropy politically: developing constituencies to build support for policy positions and generate third party advocacy; weakening opposing political constituencies; facilitating access and building relationships with policymakers; creating direct leverage with policymakers by providing financial subsidies to specific projects; enhancing the donor's status as a source of credible information; and shaping the tobacco control agenda by shifting thinking on the importance of regulating the market environment for tobacco and the relative risks of smoking for population health. Contemporary BAT social and stakeholder reports contain numerous examples of charitable donations that are likely to be designed to shape the tobacco control agenda, secure access and build constituencies. Conclusions and Recommendations Tobacco companies' political use of charitable donations underlines the need for tobacco industry philanthropy to be restricted via full implementation of Articles 5.3 and 13 of the FCTC. The model of tobacco industry philanthropy developed in this study can be used by public health advocates to press for implementation of the FCTC and provides a basis for analysing the political effects of charitable giving in other industry sectors which have an impact on public health such as alcohol and food
Influence of Maternal Dysmetabolic Conditions During Pregnancy on Cardiovascular Disease
Pathogenic factors associated with maternal hypercholesterolemia, obesity, and diabetic conditions during pregnancy influence fetal development and predispose offspring to cardiovascular disease. Animal models have established cause–effect relationships consistent with epidemiological findings in humans and have demonstrated, in principle, that interventions before or during pregnancy can reduce or prevent pathogenic in utero programming. However, little is known about the mechanisms by which maternal dysmetabolic conditions enhance disease susceptibility in offspring. Identification of these mechanisms is rendered more difficult by the fact that programming effects in offspring may be latent and may require conventional risk factors and inherited genetic co-factors to become clinically manifest. Given the increasing prevalence of maternal risk factors, which is expected to lead to a wave of cardiovascular disease in the coming decades, and the length of prospective studies on developmental programming in humans, greater-than-usual emphasis on experimental models and translational studies is necessary
Bovine telomere dynamics and the association between telomere length and productive lifespan
Average telomere length (TL) in blood cells has been shown to decline with age in a range of vertebrate species, and there is evidence that TL is a heritable trait associated with late-life health and mortality in humans. In non-human mammals, few studies to date have examined lifelong telomere dynamics and no study has estimated the heritability of TL, despite these being important steps towards assessing the potential of TL as a biomarker of productive lifespan and health in livestock species. Here we measured relative leukocyte TL (RLTL) in 1,328 samples from 308 Holstein Friesian dairy cows and in 284 samples from 38 female calves. We found that RLTL declines after birth but remains relatively stable in adult life. We also calculated the first heritability estimates of RLTL in a livestock species which were 0.38 (SE = 0.03) and 0.32 (SE = 0.08) for the cow and the calf dataset, respectively. RLTL measured at the ages of one and five years were positively correlated with productive lifespan (p < 0.05). We conclude that bovine RLTL is a heritable trait, and its association with productive lifespan may be used in breeding programmes aiming to enhance cow longevity
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