786 research outputs found
Radial velocity eclipse mapping of exoplanets
Planetary rotation rates and obliquities provide information regarding the
history of planet formation, but have not yet been measured for evolved
extrasolar planets. Here we investigate the theoretical and observational
perspective of the Rossiter-McLauglin effect during secondary eclipse (RMse)
ingress and egress for transiting exoplanets. Near secondary eclipse, when the
planet passes behind the parent star, the star sequentially obscures light from
the approaching and receding parts of the rotating planetary surface. The
temporal block of light emerging from the approaching (blue-shifted) or
receding (red-shifted) parts of the planet causes a temporal distortion in the
planet's spectral line profiles resulting in an anomaly in the planet's radial
velocity curve. We demonstrate that the shape and the ratio of the
ingress-to-egress radial velocity amplitudes depends on the planetary
rotational rate, axial tilt and impact factor (i.e. sky-projected planet
spin-orbital alignment). In addition, line asymmetries originating from
different layers in the atmosphere of the planet could provide information
regarding zonal atmospheric winds and constraints on the hot spot shape for
giant irradiated exoplanets. The effect is expected to be most-pronounced at
near-infrared wavelengths, where the planet-to-star contrasts are large. We
create synthetic near-infrared, high-dispersion spectroscopic data and
demonstrate how the sky-projected spin axis orientation and equatorial velocity
of the planet can be estimated. We conclude that the RMse effect could be a
powerful method to measure exoplanet spins.Comment: 7 pages, 3 figures, 1 table, accepted for publication in ApJ on 2015
June 1
Entrepreneurial academics and regional innovation systems: the case of spin-offs from London's universities
In this paper we explore the spin-off process from Londonâs universities using a regional innovation systems (RIS) framework. We examine the pattern of spin-offs in the context of changes in institutional support systems, both within the universities and in the London region. The majority of the university-related spin-offs are small and medium-sized enterprises concentrated in biomedical sectors, as elsewhere. However, over a third have left London. We explore these patterns, the implications for understanding the role of universities in RIS, and consequent policy implications
The economic and innovation contribution of universities: a regional perspective
Universities and other higher education institutions (HEIs) have come to be regarded as key sources of knowledge utilisable in the pursuit of economic growth. Although there have been numerous studies assessing the economic and innovation impact of HEIs, there has been little systematic analysis of differences in the relative contribution of HEIs across regions. This paper provides an exploration of some of these differences in the context of the UKâs regions. Significant differences are found in the wealth generated by universities according to regional location and type of institution. Universities in more competitive regions are generally more productive than those located in less competitive regions. Also, traditional universities are generally more productive than their newer counterparts, with university productivity positively related to knowledge commercialisation capabilities. Weaker regions tend to be more dependent on their universities for income and innovation, but often these universities under-perform in comparison to counterpart institutions in more competitive regions. It is argued that uncompetitive regions lack the additional knowledge infrastructure, besides universities, that are more commonly a feature of more competitive regions
The logic of the future in quantum theory
According to quantum mechanics, statements about the future made by sentient beings like us are, in general, neither true nor false; they must satisfy a many-valued logic. I propose that the truth value of such a statement should be identified with the probability that the event it describes will occur. After reviewing the history of related ideas in logic, I argue that it gives an understanding of probability which is particularly satisfactory for use in quantum mechanics. I construct a lattice of future-tense propositions, with truth values in the interval , and derive logical properties of these truth values given by the usual quantum-mechanical formula for the probability of a history
NPY Neuron-Specific Y2 Receptors Regulate Adipose Tissue and Trabecular Bone but Not Cortical Bone Homeostasis in Mice
BACKGROUND: Y2 receptor signalling is known to be important in neuropeptide Y (NPY)-mediated effects on energy homeostasis and bone physiology. Y2 receptors are located post-synaptically as well as acting as auto receptors on NPY-expressing neurons, and the different roles of these two populations of Y2 receptors in the regulation of energy homeostasis and body composition are unclear. METHODOLOGY/PRINCIPAL FINDINGS: We thus generated two conditional knockout mouse models, Y2(lox/lox) and NPYCre/+;Y2(lox/lox), in which Y2 receptors can be selectively ablated either in the hypothalamus or specifically in hypothalamic NPY-producing neurons of adult mice. Specific deletion of hypothalamic Y2 receptors increases food intake and body weight compared to controls. Importantly, specific ablation of hypothalamic Y2 receptors on NPY-containing neurons results in a significantly greater adiposity in female but not male mice, accompanied by increased hepatic triglyceride levels, decreased expression of liver carnitine palmitoyltransferase (CPT1) and increased expression of muscle phosphorylated acetyl-CoA carboxylase (ACC). While food intake, body weight, femur length, bone mineral content, density and cortical bone volume and thickness are not significantly altered, trabecular bone volume and number were significantly increased by hypothalamic Y2 deletion on NPY-expressing neurons. Interestingly, in situ hybridisation reveals increased NPY and decreased proopiomelanocortin (POMC) mRNA expression in the arcuate nucleus of mice with hypothalamus-specific deletion of Y2 receptors in NPY neurons, consistent with a negative feedback mechanism between NPY expression and Y2 receptors on NPY-ergic neurons. CONCLUSIONS/SIGNIFICANCE: Taken together these data demonstrate the anti-obesogenic role of Y2 receptors in the brain, notably on NPY-ergic neurons, possibly via inhibition of NPY neurons and concomitant stimulation of POMC-expressing neurons in the arcuate nucleus of the hypothalamus, reducing lipogenic pathways in liver and/or skeletal muscle in females. These data also reveal as an anti-osteogenic effect of Y2 receptors on hypothalamic NPY-expressing neurons on trabecular but not on cortical bone
Grouping practices in the primary school: what influences change?
During the 1990s, there was considerable emphasis on promoting particular kinds of pupil grouping as a means of raising educational standards. This survey of 2000 primary schools explored the extent to which schools had changed their grouping practices in responses to this, the nature of the changes made and the reasons for those changes. Forty eight percent of responding schools reported that they had made no change. Twenty two percent reported changes because of the literacy hour, 2% because of the numeracy hour, 7% because of a combination of these and 21% for other reasons. Important influences on decisions about the types of grouping adopted were related to pupil learning and differentiation, teaching, the implementation of the national literacy strategy, practical issues and school self-evaluation
Parental Leave policies, gender equity and family well being in Europe: a comparative perspective
Leave policies and the protection of working parents' rights have changed significantly
in Europe during the last few decades. While policies introduced immediately
after World War II were largely based on a male-breadwinner model, the post-1970s
policies have recognised the increase in maternal employment, the growing diversity
of work/family arrangements and working parents' needs for state support in caring
for young children. Paid maternity leave and paid or unpaid parental leave are
now available throughout Europe - Western, Central and Eastern - and policy developments
have encouraged more gender-neutral leaves and longer periods of paid
leave (Deven and Moss 2005)
Exploring concepts of health with male prisoners in three category-C English prisons
Lay understandings of health and illness have a well established track record and a plethora of research now exists which has examined these issues. However, there is a dearth of research which has examined the perspectives of those who are imprisoned. This paper attempts to address this research gap. The paper is timely given that calls have been made to examine lay perspectives in different geographical locations and a need to re-examine health promotion approaches in prison settings. Qualitative data from thirty-six male sentenced prisoners from three prisons in England were collected. The data was analysed in accordance with Attride-Stirling's (2001) thematic network approach. Although the men's perceptions of health were broadly similar to the general population, some interesting findings emerged which were directly related to prison life and its associated structures. These included access to the outdoors and time out of their prison cell, as well as maintaining relationships with family members through visits. The paper proposes that prisoners' lay views should be given higher priority given that prison health has traditionally been associated with medical treatment and the bio-medical paradigm more generally. It also suggests that in order to fulfil the World Health Organization's (WHO) vision of viewing prisons as health promoting settings, lay views should be recognised to shape future health promotion policy and practice
Understanding the evolution of the entrepreneurial university:The case of English Higher Education
There has been strong policy interest in universities becoming more entrepreneurial and engaging in knowledge exchange activities as part of an expanding third mission agenda. However, our understanding of the evolution and diversity of such activities is limited. Using longitudinal data from the Higher Education Business Community Interaction (HEBCI) Survey, this study examines the evolving configuration
of universities' knowledge exchange activities and stakeholders by analysing distinctive clusters of English universities. We find an increasingly diverse profile of third mission activities across different types of universities: within old, more established universities, Russell Group universities increasingly focus on researchâoriented activities typically in partnership with large firms and nonâcommercial organisations; while another group engages in a broad range of knowledge exchange activities with low specialisation over time. Newer, less research intensive, universities increasingly rely on activities such as consultancy and formation of spinâoffs. A decreased engagement with small and medium enterprises and a lower share of knowledge exchange activities at the regional level are observed across the time studied for all universities.JRC.B.4-Human Capital and Employmen
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