305 research outputs found

    Consistent supersymmetric Kaluza--Klein truncations with massive modes

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    We construct consistent Kaluza--Klein reductions of D=11 supergravity to four dimensions using an arbitrary seven-dimensional Sasaki--Einstein manifold. At the level of bosonic fields, we extend the known reduction, which leads to minimal N=2 gauged supergravity, to also include a multiplet of massive fields, containing the breathing mode of the Sasaki--Einstein space, and still consistent with N=2 supersymmetry. In the context of flux compactifications, the Sasaki--Einstein reductions are generalizations of type IIA SU(3)-structure reductions which include both metric and form-field flux and lead to a massive universal tensor multiplet. We carry out a similar analysis for an arbitrary weak G_2 manifold leading to an N=1 supergravity with massive fields. The straightforward extension of our results to the case of the seven-sphere would imply that there is a four-dimensional Lagrangian with N=8 supersymmetry containing both massless and massive spin two fields. We use our results to construct solutions of M-theory with non-relativistic conformal symmetry.Comment: 33 pages. v2: Added section on skew-whiffed solutions and some brief comments on holographic superconductors. v3: typos corrected, version to be published in JHE

    DESIGNING PORT INFRASTRUCTURE FOR SEA LEVEL CHANGE: A SURVEY OF U.S. ENGINEERS

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    Seaports are particularly vulnerable to the impacts of climate change due to their coastal location. With the potential threat of up to 2.5m in sea level rise by 2100, resilient port infrastructure is vital for the continued operation of ports. There are strong economic and social incentives for seaports to provide long-term resilience against climate conditions. For example, service disruptions can cost billions of dollars and impact the livelihoods of those who depend on the port. Engineers play a pivotal role in improving the resilience of ports, as they are responsible for designing port infrastructure that will be adequately prepared for future sea level change (SLC). However, incorporating SLC is a challenging task due to the uncertainty of SLC projections, the long service lives of port infrastructure, and the differing guidelines and recommendations for managing SLC. Through an online survey of 85 U.S. port and marine infrastructure engineers, this research explores the engineering community’s attitude and approach to planning for SLC for large-scale maritime infrastructure projects. Survey findings highlight the extent that projects incorporate SLC, the wide range of factors that drive the inclusion of SLC, and the numerous barriers that prevent engineers from incorporating SLC into design. This research emphasizes that traditional engineering practices may no longer be appropriate for dealing with climate change design variables and their associated uncertainties. Furthermore, results call for collaboration among engineers, port authorities, and policy makers to develop design standards and practical design methods for designing resilient port infrastructure

    Desiccation cracks provide evidence of lake drying on Mars, Sutton Island member, Murray formation, Gale Crater

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    Mars Science Laboratory (MSL) Curiosity rover data are used to describe the morphology of desiccation cracks observed in ancient lacustrine strata at Gale crater, Mars, and to interpret their paleoenvironmental setting. The desiccation cracks indicate subaerial exposure of lacustrine facies in the Sutton Island member of the Murray formation. In association with ripple cross-stratification and possible eolian cross-bedding, these facies indicate a transition from longer-lived perennial lakes recorded by older strata to younger lakes characterized by intermittent exposure. The transition from perennial to episodically exposed lacustrine environments provides evidence for local to regional climate change that can help constrain Mars climate models

    Cultural orientations and preference for HRM policies and practices:the case of Oman

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    This study empirically examines the influence of cultural orientations on employee preferences of human resource management (HRM) policies and practices in Oman. Data were collected from 712 employees working in six large Omani organizations. The findings indicate that there is a number of differences among Omani employees regarding value orientations due especially to age, education and work experience. The findings show a strong orientation towards mastery, harmony, thinking and doing, and a weak orientation towards hierarchy, collectivism, subjugation and human nature-as-evil. The results demonstrate a clear link between value orientations and preferences for particular HRM policies and practices. Group-oriented HRM practices are preferred by those who scored high on collectivism and being orientations, and those who scored low on thinking and doing orientations. Hierarchy-oriented HRM practices are preferred by those scoring high on hierarchy, subjugation and human nature-as-bad orientations, and those scoring low on thinking and mastery orientations. Finally, preference for loose and informal HRM practices was positively associated with being, and negatively associated with thinking, doing and harmony orientations. The theoretical and practical implications of these findings are discussed in detail

    Adverse Cardiovascular Outcomes and Antihypertensive Treatment: A Genome-Wide Interaction Meta-Analysis in the International Consortium for Antihypertensive Pharmacogenomics Studies

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    We sought to identify genome-wide variants influencing antihypertensive drug response and adverse cardiovascular outcomes, utilizing data from four randomized controlled trials in the International Consortium for Antihypertensive Pharmacogenomics Studies (ICAPS). Genome-wide antihypertensive drug-single nucleotide polymorphism (SNP) interaction tests for four drug classes (β-blockers, n = 9,195; calcium channel blockers (CCBs), n = 10,511; thiazide/thiazide-like diuretics, n = 3,516; ACE-inhibitors/ARBs, n = 2,559) and cardiovascular outcomes (incident myocardial infarction, stroke, or death) were analyzed among patients with hypertension of European ancestry. Top SNPs from the meta-analyses were tested for replication of cardiovascular outcomes in an independent Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) study (n = 21,267), blood pressure (BP) response in independent ICAPS studies (n = 1,552), and ethnic validation in African Americans from the Genetics of Hypertension Associated Treatment study (GenHAT; n = 5,115). One signal reached genome-wide significance in the β-blocker-SNP interaction analysis (rs139945292, Interaction P = 1.56 × 10−8). rs139945292 was validated through BP response to β-blockers, with the T-allele associated with less BP reduction (systolic BP response P = 6 × 10−4, Beta = 3.09, diastolic BP response P = 5 × 10−3, Beta = 1.53). The T-allele was also associated with increased adverse cardiovascular risk within the β-blocker treated patients’ subgroup (P = 2.35 × 10−4, odds ratio = 1.57, 95% confidence interval = 1.23–1.99). The locus showed nominal replication in CHARGE, and consistent directional trends in β-blocker treated African Americans. rs139945292 is an expression quantitative trait locus for the 50 kb upstream gene NTM (neurotrimin). No SNPs attained genome-wide significance for any other drugs classes. Top SNPs were located near CALB1 (CCB), FLJ367777 (ACE-inhibitor), and CES5AP1 (thiazide). The NTM region is associated with increased risk for adverse cardiovascular outcomes and less BP reduction in β-blocker treated patients. Further investigation into this region is warranted
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