Vision screening in children:a retrospective study of social and demographic factors with regard to visual outcomes

BACKGROUND: Amblyopia and its risk factors have been demonstrated to be more common among children from low socioeconomic backgrounds. We sought to investigate this association in a region with orthoptic-delivered screening and whole population coverage, and to also examine the association of the Health Plan Indicator (HPI) with screening outcome. METHODS: Screening examination outcomes, postcodes and HPIs were extracted from the community child health database for every child who underwent preschool vision screening between March 2010 and February 2011 Tayside. We obtained the Scottish Index of Multiple Deprivation score for every child as a measure of area-based deprivation. We assessed the vulnerability/needs of the individual family through the HPI—‘Core’ (children and families receiving universal health visiting service), ‘Additional’ (receiving additional health/social support) and ‘Intensive’ (receiving high levels of support). The outcomes from follow-up examinations for those who failed screening were extracted from the orthoptic department database. RESULTS: 4365 children were screened during the year 2010–2011 of whom 523 (11.9%) failed. The odds of children from the least deprived socioeconomic group passing the visual screening test was 1.4 times higher than those from the most deprived socioeconomic group (OR 1.4, 95% CI 1.07 to 1.89, p=0.01). The odds of a child from a family assigned as ‘Intensive’ failing the preschool visual screening test was three times greater than the odds of a child from a family assigned as ‘Core’ (OR 3.59, 95% CI 1.6 to 7.8, p=0.001). CONCLUSIONS: We found that children from the most deprived backgrounds and those from unstable homes were more likely to fail preschool vision screening

Parallaxes and proper motions for 20 open clusters as based on the new Hipparcos catalogue

A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming that the accuracies for nearly all stars brighter than magnitude $\mathrm{Hp}=8$ are improved, by up to a factor 4, compared to the original catalogue. As correlations between the underlying abscissa residuals have also been reduced by more than an order of magnitude to an insignificant level, our ability to determine reliable parallaxes and proper motions for open clusters should be improved. The new Hipparcos astrometric catalogue is used to derive mean parallax and proper motion estimates for 20 open clusters. The HR-diagrams of the nearest clusters are compared and combined to provide future input to sets of observational isochrones. The positions of the cluster HR diagrams are consistent within different groups of clusters shown for example by the near-perfect alignment of the sequences for the Hyades and Praesepe, for Coma Ber and UMa, and for the Pleiades, NGC 2516, and Blanco 1. The groups are mutually consistent when systematic differences in $\Delta c_0$ are taken into account, where the effect of these differences on the absolute magnitudes has been calibrated using field-star observations.Comment: 34 pages, 36 figures, 7 tables. Accepted for publication by A&

Invariant template matching in systems with spatiotemporal coding: a vote for instability

We consider the design of a pattern recognition that matches templates to images, both of which are spatially sampled and encoded as temporal sequences. The image is subject to a combination of various perturbations. These include ones that can be modeled as parameterized uncertainties such as image blur, luminance, translation, and rotation as well as unmodeled ones. Biological and neural systems require that these perturbations be processed through a minimal number of channels by simple adaptation mechanisms. We found that the most suitable mathematical framework to meet this requirement is that of weakly attracting sets. This framework provides us with a normative and unifying solution to the pattern recognition problem. We analyze the consequences of its explicit implementation in neural systems. Several properties inherent to the systems designed in accordance with our normative mathematical argument coincide with known empirical facts. This is illustrated in mental rotation, visual search and blur/intensity adaptation. We demonstrate how our results can be applied to a range of practical problems in template matching and pattern recognition.Comment: 52 pages, 12 figure

Who do we inform? The role of status and target in intergroup whistle-blowing

In two experiments (n = 87 and n = 90), we showed that strongly identifying members of a low status group are more likely to actively inform the ingroup rather than the outgroup about an outgroup transgression, and consider it as more loyal to the ingroup to do so. Moreover, strongly identifying members of a high status group are more likely to actively inform the outgroup rather than the ingroup about an outgroup transgression, and consider this to be more loyal to the ingroup. The results are in support of the notion that, depending on a group's existing status position, negative outgroup information can be used to enhance or confirm the ingroup's standing, affecting whether the ingroup or the outgroup will initially be informed about an outgroup transgression. Copyright © The Author(s), 2009

Intergroup helping in response to separatism

Despite its prevalence and widespread media coverage, separatism as a phenomenon is barely covered in psychological investigations, and the majority's response to separatism has been completely ignored. We present two studies in which we investigated the notion that separatist movements threaten the continuation of the national identity, as well as the nation's economic position. Moreover, we hypothesized and found that members of the majority group respond to continuation threat by supporting government measures to help the separatist group. Javanese students who were induced to believe that existing separatist movements in West Papua (Study 1, N = 322) or Aceh (Study 2, N = 180) were currently increasing their efforts to gain independence were more willing to support these groups than participants who believed these movements were dormant. Moreover, this effect was mediated by continuation threat but not economic threat. These results demonstrate the possibility of a peaceful response to separatism threat. © 2013 by the Society for Personality and Social Psychology, Inc

Using Galactic Cepheids to verify Gaia parallaxes

Context. The Gaia satellite will measure highly accurate absolute parallaxes of hundreds of millions of stars by comparing the parallactic displacements in the two fields of view of the optical instrument. The requirements on the stability of the 'basic angle' between the two fields are correspondingly strict, and possible variations (on the microarcsec level) are therefore monitored by an on-board metrology system. Nevertheless, since even very small periodic variations of the basic angle might cause a global offset of the measured parallaxes, it is important to find independent verification methods. Aims. We investigate the potential use of Galactic Cepheids as standard candles for verifying the Gaia parallax zero point. Methods. We simulate the complete population of Galactic Cepheids and their observations by Gaia. Using the simulated data, simultaneous fits are made of the parameters of the period-luminosity relation and a global parallax zero point. Results. The total number of Galactic Cepheids is estimated at about 20 000, of which nearly half could be observed by Gaia. In the most favourable circumstances, including negligible intrinsic scatter and extinction errors, the determined parallax zero point has an uncertainty of 0.2 microarcsec. With more realistic assumptions the uncertainty is several times larger, and the result is very sensitive to errors in the applied extinction corrections. Conclusions. The use of Galactic Cepheids alone will not be sufficient to determine a possible parallax zero-point error to the full potential systematic accuracy of Gaia. The global verification of Gaia parallaxes will most likely depend on a combination of many different methods, including this one.Comment: 7 pages, 6 figures. Accepted for publication in Astronomy and Astrophysic

The geological history of the Latimojong region of western Sulawesi, Indonesia

We present an updated geological map and revised stratigraphy of the Latimojong region of central-western Sulawesi. This work includes new biostratigraphic ages from the Latimojong Metamorphic Complex, Toraja Group, Makale Formation and Enrekang Volcanics, together with whole-rock geochemical data and sensitive high-resolution ion microprobe (SHRIMP) U-Pb analyses from zircons extracted from igneous rocks in the region. Previous work on the study region and in other parts of Sulawesi have discussed the age and character of two different rock sequences with similar names, the Latimojong Complex and the Latimojong Formation. One would assume that the type location for these two sequences is in the Latimojong Mountains. However, there is considerable confusion as to the character and location of these sequences. We make a distinction between the Latimojong Formation and the Latimojong Complex, and propose that the Latimojong Complex be renamed the Latimojong Metamorphic Complex to minimise the confusion associated with the current nomenclature. The Latimojong Metamorphic Complex is an accretionary complex of low- to high-grade metamorphic rocks tectonically mixed with cherts and ophiolitic rocks, while the Latimojong Formation consists of Upper Cretaceous weakly deformed, unmetamorphosed sediments or very low-grade metasediments (previously interpreted as flysch or distal turbidites that unconformably overlie older rocks). Our work indicates that the Latimojong Formation must be restricted to isolated, unobserved segments of the Latimojong Mountains, or are otherwise not present in the Latimojong region, meaning the Latimojong Formation would only be found further north in western Sulawesi. Radiolaria extracted from chert samples indicate that the Latimojong Metamorphic Complex was likely assembled during the Cretaceous (Aptian-Albian) and was later metamorphosed. Ages obtained from benthic and planktonic foraminifera were used to differentiate and map the Toraja Group (Ypresian to Chattian: 56-23 Ma), Makale Formation (Burdigalian to Serravallian: 20.5-11.5 Ma) and Enrekang Volcanic Series (8.0-3.6 Ma) across the study area. U-Pb isotopic data collected from magmatic zircons record several phases of volcanism (∼38 Ma, ∼25 Ma and 8.0-3.6 Ma) in the region. Each phase of magmatism can be distinguished according to petrology and whole-rock geochemical data. The isotopic ages also show that dacites from the Enrekang Volcanic Series are contemporaneous with the emplacement of the Palopo Granite (6.6-4.9 Ma). Miocene to Proterozoic inherited zircons within these igneous rocks support earlier suggestions that Sulawesi potentially has a Proterozoic-Phanerozoic basement or includes sedimentary rocks (and therefore detrital zircons) derived from the erosion of Proterozoic or younger material. Some earlier work proposed that the granitic rocks in the region developed due to crustal melting associated with plate collision and radiogenic heating. Our observations however, support different interpretations, where the granites are associated with arc magmatism and/or crustal extension. The region was cross-cut by major strike-slip fault zones during the Pliocene. This deformation and the buoyancy associated with relatively young intrusions may have facilitated uplift of the mountains

Chemical compositions of stars in two stellar streams from the Galactic thick disk

We present abundances for 20 elements for stars in two stellar streams identified by Arifyanto & Fuchs (2006, A&A, 449, 533): 18 stars from the Arcturus stream and 26 from a new stream, which we call AF06 stream, both from the Galactic thick disk. Results show both streams are metal-poor and very old (10$-$14 Gyrs) with kinematics and abundances overlapping with the properties of local field thick disk stars. Both streams exhibit a range in metallicity but with relative elemental abundances that are identical to those of thick disk stars of the same metallicity. These results show that neither stream can result from dissolution of an open cluster. It is highly unlikely that either stream represents tidal debris from an accreted satellite galaxy. Both streams most probably owe their origin to dynamical perturbations within the Galaxy.Comment: 10 figures, Accepted for publication in MNRA

The provenance of Borneo's enigmatic alluvial diamonds:A case study from Cempaka, SE Kalimantan

Gem-quality diamonds have been found in several alluvial deposits across central and southern Borneo. Borneo has been a known source of diamonds for centuries, but the location of their primary igneous source remains enigmatic. Many geological models have been proposed to explain their distribution, including: the diamonds were derived from a local diatreme; they were brought to the surface through ophiolite obduction or exhumation of UHP metamorphic rocks; they were transported long distances southward via major Asian river systems; or, they were transported from the Australian continent before Borneo was rifted from its northwestern margin in the Late Jurassic. To assess these models, we conducted a study of the provenance of heavy minerals from Kalimantan's Cempaka alluvial diamond deposit. This involved collecting U–Pb isotopic data, fission track and trace element geochemistry of zircon as well as major element geochemical data of spinels and morphological descriptions of zircon and diamond. The results indicate that the Cempaka diamonds were likely derived from at least two sources, one which was relatively local and/or involved little reworking, and the other more distal which records several periods of reworking. The distal diamond source is interpreted to be diamond-bearing pipes that intruded the basement of a block that: (1) rifted from northwest Australia (East Java or SW Borneo) and the diamonds were recycled into its sedimentary cover, or: (2) were emplaced elsewhere (e.g. NW Australia) and transported to a block (e.g. East Java or SW Borneo). Both of these scenarios require the diamonds to be transported with the block when it rifted from NW Australia in the Late Jurassic. The local source could be diamondiferous diatremes associated with eroded Miocene high-K alkaline intrusions north of the Barito Basin, which would indicate that the lithosphere beneath SW Borneo is thick (~ 150 km or greater). The ‘local’ diamonds could also be associated with ophiolitic rocks that are exposed in the nearby Meratus Mountains

Theoretical Principles of Single-Molecule Electronics: A Chemical and Mesoscopic View

Exploring the use of individual molecules as active components in electronic devices has been at the forefront of nanoelectronics research in recent years. Compared to semiconductor microelectronics, modeling transport in single-molecule devices is much more difficult due to the necessity of including the effects of the device electronic structure and the interface to the external contacts at the microscopic level. Theoretical formulation of the problem therefore requires integrating the knowledge base in surface science, electronic structure theory, quantum transport and device modeling into a single unified framework starting from the first-principles. In this paper, we introduce the theoretical framework for modeling single-molecule electronics and present a simple conceptual picture for interpreting the results of numerical computation. We model the device using a self-consistent matrix Green's function method that combines Non-Equilibrium Green's function theory of quantum transport with atomic-scale description of the device electronic structure. We view the single-molecule device as "heterostructures" composed of chemically well-defined atomic groups, and analyze the device characteristics in terms of the charge and potential response of these atomic groups to perturbation induced by the metal-molecule coupling and the applied bias voltage. We demonstrate the power of this approach using as examples devices formed by attaching benzene-based molecules of different size and internal structure to the gold electrodes through sulfur end atoms.Comment: To appear in International Journal of Quantum Chemistry, Special Issue in memory of J.A. Pople. 13 pages, 9 figure