Metastable Flux Configurations and de Sitter Spaces

We derive stability conditions for the critical points of the no-scale scalar potential governing the dynamics of the complex structure moduli and the axio-dilaton in compactifications of type IIB string theory on Calabi-Yau three-folds. We discuss a concrete example of a T^6 orientifold. We then consider the four-dimensional theory obtained from compactifications of type IIB string theory on non-geometric backgrounds which are mirror to rigid Calabi-Yau manifolds and show that the complex structure moduli fields can be stabilized in terms of H_{RR} only, i.e. with no need of orientifold projection. The stabilization of all the fields at weak coupling, including the axio-dilaton, may require to break supersymmetry in the presence of H_{NS} flux or corrections to the scalar potential.Comment: 24 page

Translating Christianity in an Age of Reformations

This article argues that the age of the Protestant and Catholic Reformations and the global spread of the latter brought with it the challenge that not only was it necessary to learn new languages in order to communicate the Christian message to non-European peoples encountered during the so-called ‘Age of Discovery’, but some kind of control had to be exercised over the new, global circulation of sacred images and relics. The latter facilitated the visual (and virtual) translation of such holy sites as Jerusalem and Rome and its specific holy treasures in the mental prayers of the faithful. It concludes that it was less Lamin Sanneh’s ‘triumph of [linguistic] translatability’ and more the physical translatability of the sacred that made possible the emergence of Roman Catholicism as this planet’s first world religion

Simulating arbitrary hyperspectral bandsets from multispectral observations via a generic Earth Observation-Land Data Assimilation System (EO-LDAS)

This paper presents results of using multi-sensor and multi-angular constraints in the generic Earth Observation-Land Data Assimilation System (EO-LDAS) for reproducing arbitrary bandsets of hyperspectral reflectance at the top-of-canopy (TOC) level by merging observations from multispectral sensors with different spectral characteristics. This is demonstrated by combining Multi-angle Imaging Spectroradiometer (MISR) and Landsat Enhanced Thematic Mapper Plus (ETM+) data to simulate the Compact High Resolution Imaging Spectrometer CHRIS/PROBA hyperspectral signal over an agricultural test site, in Barrax, Spain. However, the method can be more generally applied to any combination of spectral data, providing a tool for merging EO data to any arbitrary hyperspectral bandset. Comparisons are presented using both synthetic and observed MISR and Landsat data, and retrieving surface biophysical properties. We find that when using simulated MISR and Landsat data, the CHRIS/PROBA hyperspectral signal is reproduced with RMSE 0.0001– 0.04. LAI is retrieved with r2 from 0.97 to 0.99 and RMSE of from 0.21 to 0.38. The results based on observed MISR and Landsat data have lower performances, with RMSE for the reproduced CHRIS/PROBA hyperspectral signal varying from 0.007 to 0.2. LAI is retrievedwith r2 from 0.7 to 0.9 and RMSE from 0.7 to 1.4. We found that for the data considered here the main spectral variations in the visible and near infrared regions can be described by a limited number of parameters (3–4) that can be estimated from multispectral information. Results show that the method can be used to simulate arbitrary bandsets, which will be of importance to any application which requires combining new and existing streams of new EO data in the optical domain, particularly intercalibration of EO satellites in order to get continuous time series of surface reflectance, across programmes and sensors of different designs

Forest disturbance and regeneration: a mosaic of discrete gap dynamics and open matrix regimes?

Question: Recent research in boreal forest suggests that an ‘open matrix’ model may be more appropriate than the traditional model of spatially discrete gap dynamics for describing forest disturbance and regeneration, but what is the evidence from temperate broad-leaved deciduous forests concerning the prevalence of these alternative models? Location: Semi-natural temperate broad-leaved deciduous forest in southern England. Methods: Multi-temporal LiDAR data were used to monitor the changes in tree canopy height and canopy gaps over a 10-yr period for a 130-ha area of forest. Gap dynamics were characterized by quantifying gap creation, expansion, contraction and closure. By identifying the types and rates of canopy height transitions, areas of gap contraction and closure were attributed to the processes of lateral crown growth or vertical regeneration. Results: Across the study site there was a zonation in canopy and gap properties and their dynamics. Many areas of the forest had the characteristics of open wood-pasture dominated by large, complex gaps being maintained under a regime of chronic disturbance. In these areas, several characteristics of the gap dynamics indicated that regeneration was restricted and this may be attributable to spatially-focused overgrazing by large herbivores. In contrast, other areas were characterized by high, closed canopy forest with small, discrete gaps where gap creation and infill were balanced. Conclusions: At the landscape-scale broad-leaved deciduous forests contain a spatial mosaic of zones, which conform to different models of disturbance and regeneration dynamics; discrete gap dynamics and open matrix regimes are juxtaposed. It is now important to elucidate the abiotic factors and biotic interactions that determine the spatio-temporal distribution of the different regimes and to examine whether such a ‘regime mosaic’ model is applicable in other forest types

Global Emission Line Trends in Spiral Galaxies: The Reddening and Metallicity Sequences

We have explored the emission line trends in the integrated spectra of normal spiral galaxies of the Nearby Field Galaxy Survey, in order to investigate the relationships between dust extinction, metallicity and some macroscopic properties of spiral galaxies. We found a very strong correlation between the Hbeta and Halpha equivalent widths, implying that the difference between the extinction of the stellar and the nebular light depends only on the intrinsic colours of the galaxies, being larger for redder galaxies. The usual metallicity indicator for giant HII regions ([OIII]4959,5007 + [OII]3726,3729)/ Hbeta is not appropriate for integrated spectra of spiral galaxies, probably due to metallicity gradients. Much better qualitative metallicity indicators are found to be [NII]6584/[OII]3726,3729 and [NII]6584/Halpha, the latter having the advantage of being independent of reddening and being applicable also for galaxies with weak emission lines. With these indicators, we find that the nebular extinction as derived from the Balmer decrement strongly correlates with the effective metallicity of the emission line regions. The overall metallicity of the emission line regions is much better correlated with galaxy colours than with morphological types. A Principal Component Analysis on a 7-D parameter space showed that the variance is produced, in first place, by the metallicity and parameters linked to the stellar populations, and, in second place, by the surface brightness, which is linked to the dynamical history of the galaxies. The absolute magnitude, related to the mass of the galaxy, comes only in the third place.Comment: 13 pages; to appear in A&

Time to endoscopy for acute upper gastrointestinal bleeding::Results from a prospective multicentre trainee-led audit

Background: Endoscopy within 24?h of admission (early endoscopy) is a quality standard in acute upper gastrointestinal bleeding (AUGIB). We aimed to audit time to endoscopy outcomes and identify factors affecting delayed endoscopy (>24h of admission).Methods: This prospective multicentre audit enrolled patients admitted with AUGIB who underwent inpatient endoscopy between November and December 2017. Analyses were performed to identify factors associated with delayed endoscopy, and to compare patient outcomes, including length of stay and mortality rates, between early and delayed endoscopy groups.Results: Across 348 patients from 20 centres, the median time to endoscopy was 21.2h (IQR 12.0-35.7), comprising median admission to referral and referral to endoscopy times of 8.1?h (IQR 3.7-18.1) and 6.7?h (IQR 3.0-23.1), respectively. Early endoscopy was achieved in 58.9%, although this varied by centre (range: 31.0% - 87.5%, p=0.002). On multivariable analysis, lower Glasgow-Blatchford score, delayed referral, admissions between 7:00 and 19:00 hours or via the emergency department were independent predictors of delayed endoscopy. Early endoscopy was associated with reduced length of stay (median difference 1 d; p=0.004), but not 30-d mortality (p=0.344).Conclusions: The majority of centres did not meet national standards for time to endoscopy. Strategic initiatives involving acute care services may be necessary to improve this outcome

A case study of physical and social barriers to hygiene and child growth in remote Australian Aboriginal communities

Background\ud Despite Australia's wealth, poor growth is common among Aboriginal children living in remote communities. An important underlying factor for poor growth is the unhygienic state of the living environment in these communities. This study explores the physical and social barriers to achieving safe levels of hygiene for these children.\ud \ud Methods\ud A mixed qualitative and quantitative approach included a community level cross-sectional housing infrastructure survey, focus groups, case studies and key informant interviews in one community.\ud \ud Results\ud We found that a combination of crowding, non-functioning essential housing infrastructure and poor standards of personal and domestic hygiene underlie the high burden of infection experienced by children in this remote community.\ud \ud Conclusion\ud There is a need to address policy and the management of infrastructure, as well as key parenting and childcare practices that allow the high burden of infection among children to persist. The common characteristics of many remote Aboriginal communities in Australia suggest that these findings may be more widely applicable

Risky Decisions and Their Consequences: Neural Processing by Boys with Antisocial Substance Disorder

Adolescents with conduct and substance problems ("Antisocial Substance Disorder" (ASD)) repeatedly engage in risky antisocial and drug-using behaviors. We hypothesized that, during processing of risky decisions and resulting rewards and punishments, brain activation would differ between abstinent ASD boys and comparison boys.We compared 20 abstinent adolescent male patients in treatment for ASD with 20 community controls, examining rapid event-related blood-oxygen-level-dependent (BOLD) responses during functional magnetic resonance imaging. In 90 decision trials participants chose to make either a cautious response that earned one cent, or a risky response that would either gain 5 cents or lose 10 cents; odds of losing increased as the game progressed. We also examined those times when subjects experienced wins, or separately losses, from their risky choices. We contrasted decision trials against very similar comparison trials requiring no decisions, using whole-brain BOLD-response analyses of group differences, corrected for multiple comparisons. During decision-making ASD boys showed hypoactivation in numerous brain regions robustly activated by controls, including orbitofrontal and dorsolateral prefrontal cortices, anterior cingulate, basal ganglia, insula, amygdala, hippocampus, and cerebellum. While experiencing wins, ASD boys had significantly less activity than controls in anterior cingulate, temporal regions, and cerebellum, with more activity nowhere. During losses ASD boys had significantly more activity than controls in orbitofrontal cortex, dorsolateral prefrontal cortex, brain stem, and cerebellum, with less activity nowhere.Adolescent boys with ASD had extensive neural hypoactivity during risky decision-making, coupled with decreased activity during reward and increased activity during loss. These neural patterns may underlie the dangerous, excessive, sustained risk-taking of such boys. The findings suggest that the dysphoria, reward insensitivity, and suppressed neural activity observed among older addicted persons also characterize youths early in the development of substance use disorders

West Africa in the British Atlantic: trade, violence, and empire in the 1640s

The importance of Africa and African agency in the formation of the Atlantic world is now widely acknowledged by historians, but Africa has drawn less attention than other regions in analyses of the British Atlantic. Drawing upon the nascent methodology of global microhistory, this article contributes to a scholarly rebalancing by examining two maritime lawsuits from the 1640s concerning British voyages to Senegambia and Sierra Leone, both of which resulted in conflict between British seafarers and with their African trading partners. A close study of the documents surviving from these lawsuits provides an unusually detailed glimpse of these particular moments of contact and violence across cultures. More fundamentally, such an approach illuminates the ocean-spanning networks within which these ventures took place, and reveals the ways in which British traders and sailors perceived trade in Africa within their own legal frameworks. This article argues that by the middle of the seventeenth century, as merchants and politicians in Britain began to imagine an Atlantic empire, trade in West Africa was an important part of their vision of the Atlantic world