Natural variation in female reproductive hormones does not affect contrast sensitivity.

Evidence suggests that females experience adaptive shifts in facial preferences across the menstrual cycle. However, recent discussions and meta-analyses suggest that these findings are equivocal. A previously unexplored question is the extent to which shifts in female preferences are modulated by hormone-dependent changes occurring in low-level vision, such as visual sensitivity. This mechanistic approach has been a novel method for investigating the extent to which complex perceptual phenomena are driven by low-level versus higher-level perceptual processes. We investigated whether the contrast sensitivity function-an early dimension of vision-is also influenced by variation in female reproductive hormones. Visual contrast thresholds were measured for 1, 4 and 16 cycles/degree gratings during the ovulatory, luteal and menstrual phases of the menstrual cycle in naturally cycling women, and women using oral contraceptives. Male participants were tested at similar time intervals. Results showed that visual contrast sensitivity does not differ according to sex, or use of oral contraception, nor does it vary relative to hormonal shifts across the menstrual cycle. These findings suggest that shifts in female preferences are not driven by changes in visual sensitivity, and are therefore likely attributable to changes in higher-level perception or cognition

Discrete mode laser diodes with ultra narrow linewidth emission <3kHz

Ex-facet, free-running ultra-low linewidth (<3 kHz), single mode laser emission is demonstrated using low cost, regrowth-free ridge waveguide discrete mode Fabry-Perot laser diode chips

Hospitality codes and social exchange theory : the Pashtunwali and tourism in Afghanistan

The Afghan people are shrouded in rumor, myth and superstition. Drawing upon insights from military personnel, intelligence operatives, journalists and others, this study uses Social Exchange Theory (SET) to frame our understanding of their underpinning cultural code, the Pashtunwali. The study contributes both theoretically and empirically: The nature of the Pashtunwali highlights that SET cannot adequately frame some cultural exchange practices and a hybrid framework for negotiated and reciprocal exchange is presented. Furthermore, contextually, this is the first study that explores a code of hospitality through a social exchange lens to explore potential tourism development. A framework exists upon which commercial activity can be built without altering beliefs, social dynamics or day to day pursuits. For commercial development to be successful, it must yield similar or greater levels of income to those that currently exist, more importantly, traditions of autonomy and self-dependence will affect employment and training within an emergent tourism industry

A Replica Inference Approach to Unsupervised Multi-Scale Image Segmentation

We apply a replica inference based Potts model method to unsupervised image segmentation on multiple scales. This approach was inspired by the statistical mechanics problem of "community detection" and its phase diagram. Specifically, the problem is cast as identifying tightly bound clusters ("communities" or "solutes") against a background or "solvent". Within our multiresolution approach, we compute information theory based correlations among multiple solutions ("replicas") of the same graph over a range of resolutions. Significant multiresolution structures are identified by replica correlations as manifest in information theory overlaps. With the aid of these correlations as well as thermodynamic measures, the phase diagram of the corresponding Potts model is analyzed both at zero and finite temperatures. Optimal parameters corresponding to a sensible unsupervised segmentation correspond to the "easy phase" of the Potts model. Our algorithm is fast and shown to be at least as accurate as the best algorithms to date and to be especially suited to the detection of camouflaged images.Comment: 26 pages, 22 figure

Study of the inner dust envelope and stellar photosphere of the AGB star R Doradus using SPHERE/ZIMPOL

We use high-angular-resolution images obtained with SPHERE/ZIMPOL to study the photosphere, the warm molecular layer, and the inner wind of the close-by oxygen-rich AGB star R Doradus. We present observations in filters V, cntH$\alpha$, and cnt820 and investigate the surface brightness distribution of the star and of the polarised light produced in the inner envelope. Thanks to second-epoch observations in cntH$\alpha$, we are able to see variability on the stellar photosphere. We find that in the first epoch the surface brightness of R Dor is asymmetric in V and cntH$\alpha$, the filters where molecular opacity is stronger, while in cnt820 the surface brightness is closer to being axisymmetric. The second-epoch observations in cntH$\alpha$ show that the morphology of R Dor changes completely in a timespan of 48 days to a more axisymmetric and compact configuration. The polarised intensity is asymmetric in all epochs and varies by between a factor of 2.3 and 3.7 with azimuth for the different images. We fit the radial profile of the polarised intensity using a spherically symmetric model and a parametric description of the dust density profile, $\rho(r)=\rho_\circ r^{-n}$. On average, we find exponents of $- 4.5 \pm 0.5$ that correspond to a much steeper density profile than that of a wind expanding at constant velocity. The dust densities we derive imply an upper limit for the dust-to-gas ratio of $\sim 2\times10^{-4}$ at 5.0 $R_\star$. Given the uncertainties in observations and models, this value is consistent with the minimum values required by wind-driving models for the onset of a wind, of $\sim 3.3\times10^{-4}$. However, if the steep density profile we find extends to larger distances from the star, the dust-to-gas ratio will quickly become too small for the wind of R Dor to be driven by the grains that produce the scattered light.Comment: 10 pages, 8 figures, 4 table

Exploring Pompeii: discovering hospitality through research synergy

Hospitality research continues to broaden through an ever-increasing dialogue and alignment with a greater number of academic disciplines. This paper demonstrates how an enhanced understanding of hospitality can be achieved through synergy between archaeology, the classics and sociology. It focuses on classical Roman life, in particular Pompeii, to illustrate the potential for research synergy and collaboration, to advance the debate on hospitality research and to encourage divergence in research approaches. It demonstrates evidence of commercial hospitality activities through the excavation hotels, bars and taverns, restaurants and fast food sites. The paper also provides an example of the benefits to be gained from multidisciplinary analysis of hospitality and tourism

Analysis of White Dwarfs with Strange-Matter Cores

We summarize masses and radii for a number of white dwarfs as deduced from a combination of proper motion studies, Hipparcos parallax distances, effective temperatures, and binary or spectroscopic masses. A puzzling feature of these data is that some stars appear to have radii which are significantly smaller than that expected for a standard electron-degenerate white-dwarf equations of state. We construct a projection of white-dwarf radii for fixed effective mass and conclude that there is at least marginal evidence for bimodality in the radius distribution forwhite dwarfs. We argue that if such compact white dwarfs exist it is unlikely that they contain an iron core. We propose an alternative of strange-quark matter within the white-dwarf core. We also discuss the impact of the so-called color-flavor locked (CFL) state in strange-matter core associated with color superconductivity. We show that the data exhibit several features consistent with the expected mass-radius relation of strange dwarfs. We identify eight nearby white dwarfs which are possible candidates for strange matter cores and suggest observational tests of this hypothesis.Comment: 11 pages, 6 figures, accepted for publication in J. Phys. G: Nucl. Part. Phy

Food security : the Athenian grain-tax law of 374/3 BC

This paper examines the translation of the Athenian Grain-Tax Law established in 374/3 BC, the period often referred to as early Classical antiquity. A particular focus is placed on the potential contribution of 'accounting history' as a means of exploring the use of grain tax to ensure food security. In terms of historic interpretations, the Grain-Tax is a relatively new piece of evidence discovered in the Athenian market place excavations of 1986 and, as yet, not known to have been studied within accounting research. Empirical research for this paper took the form of a hermeneutic analysis. The focus of examination was our translation of a Marble Stele inscribed in Greek with the Athenian Grain-Tax Law of 374/3 BC. This included a linguistic translation by the authors taking into account alternative translations of the Grain-Tax from other disciplines and placing the evidence in context through symbolic interpretations of other artifacts of the time based on fieldwork research. Emphasis was placed on the method of accounting for tax collection depicted by the Grain-Tax. Our interpretation of the tax highlights the challenges of researching the interchangeable nature of grain and coinage as a 'currency' for payment including aspects of measurability alongside accountability and the potential implications of this for the use of the tax system as a means of ensuring food security. Drawing new evidence for accounting research from Classical Athens and further exploring the use of hermeneutics within accounting history as a means to increase the scope of what is viewed as evidence in accounting history