High-Contrast Observations in Optical and Infrared Astronomy

High-contrast observations in optical and infrared astronomy are defined as any observation requiring a technique to reveal a celestial object of interest that is in such close angular proximity to another source brighter by a factor of at least 10^5 that optical effects hinder or prevent the collection of photons directly from the target of observation. This is a relatively new type of observation that enables research on previously obscured parts of the Universe. In particular, it is most applicable to Comparative Planetary Science, a field that directly attacks such questions as "how common are planetary systems? What types of planets exist, and are there planets other than Earth that are capable of supporting life as we know it?" We survey the scientific motivations for high-contrast observations, provide an overview of the techniques currently being used or developed, and discuss some ideas and studies for future prospects.Comment: In press for Annual Review of Astronomy and Astrophysics (Vol. 47). 46 pages, 15 figure

A case of septicaemic anthrax in an intravenous drug user

<p><b>Background:</b> In 2000, Ringertz et al described the first case of systemic anthrax caused by injecting heroin contaminated with anthrax. In 2008, there were 574 drug related deaths in Scotland, of which 336 were associated with heroin and or morphine. We report a rare case of septicaemic anthrax caused by injecting heroin contaminated with anthrax in Scotland.</p> <p><b>Case Presentation:</b> A 32 year old intravenous drug user (IVDU), presented with a 12 hour history of increasing purulent discharge from a chronic sinus in his left groin. He had a tachycardia, pyrexia, leukocytosis and an elevated C-reactive protein (CRP). He was treated with Vancomycin, Clindamycin, Ciprofloxacin, Gentamicin and Metronidazole. Blood cultures grew Bacillus anthracis within 24 hours of presentation. He had a computed tomography (CT) scan and magnetic resonance imagining (MRI) of his abdomen, pelvis and thighs performed. These showed inflammatory change relating to the iliopsoas and an area of necrosis in the adductor magnus.</p> <p>He underwent an exploration of his left thigh. This revealed chronically indurated subcutaneous tissues with no evidence of a collection or necrotic muscle. Treatment with Vancomycin, Ciprofloxacin and Clindamycin continued for 14 days. Negative Pressure Wound Therapy (NPWT) device was applied utilising the Venturi™ wound sealing kit. Following 4 weeks of treatment, the wound dimensions had reduced by 77%.</p> <p><b>Conclusions:</b> Although systemic anthrax infection is rare, it should be considered when faced with severe cutaneous infection in IVDU patients. This case shows that patients with significant bacteraemia may present with no signs of haemodynamic compromise. Prompt recognition and treatment with high dose IV antimicrobial therapy increases the likelihood of survival. The use of simple wound therapy adjuncts such as NPWT can give excellent wound healing results.</p&gt

Variations in Pastors’ Perceptions of the Etiology of Depression By Race and Religious Affiliation

Depression is a major, preventable problem in the United States, yet relatively few individuals seek care in traditional mental health settings. Instead, many choose to confide in friends, family, or clergy. Thus, it is important to discover how clergy perceive the definition of and etiology of depression. The author conducted a survey with 204 Protestant pastors in California. Multinomial logistic regression revealed a statistically significant difference in how depression is perceived based on race. Caucasian American pastors more readily agreed with the statement that depression was a biological mood disorder, while African American pastors more readily agreed that depression was a moment of weakness when dealing with trials and tribulations. Also, mainline Protestants more frequently disagreed with statements about spiritual causes of depression than Pentecostals and non-denominational pastors. The findings suggest that racial and religious affiliational influences shape how pastors view, and ultimately intervene, in the area of depression

Building blocks: a strategy for near-term action within the new global climate framework

The Paris Agreement cemented a new framework for global climate policy based on the voluntary and non-legally binding emission reduction actions by both developed and developing countries. The building blocks strategy for climate action discussed in this Special Issue is well adapted to and strongly complements this new structure. Building blocks focus on multiple transnational mechanisms for mobilizing a wide range of both public and private actors to take actions that reduce emissions by capturing incentives other than climate mitigation as such. The initial commitments by countries under the Paris Agreement are insufficient to meet the level of action required to stabilize the global climate system at a safe level. As such, new voluntary action by public and private actors will be required. The building blocks strategy, and the examples presented in this Special Issue, offers answers to the question of how to generate and design smaller-scale initiatives

Resolving the ancestry of Austronesian-speaking populations

There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The “out-of-Taiwan” model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion

Subarachnoid Hemorrhage Misdiagnosed as an Acute ST Elevation Myocardial Infarction

Without significant coronary artery stenosis, ischemic electrocardiographic change including ST segment elevation, segmental wall motion abnormality and elevated serum cardiac-specific markers (creatine kinase-MB, Troponin-T) may develop after central nervous system injuries such as subarachnoid, intracranial or subdural hemorrhage. Misdiagnosing these patients as acute myocardial infarction may result in catastrophic outcomes. By reporting a case of a 55-year old female with subarachnoid hemorrhage mimicking acute ST elevation myocardial infarction, we hope to underline that careful attention of neurologic abnormality is critical in making better prognosis

Arsenic as an Endocrine Disruptor: Arsenic Disrupts Retinoic Acid Receptor–and Thyroid Hormone Receptor–Mediated Gene Regulation and Thyroid Hormone–Mediated Amphibian Tail Metamorphosis

Background: Chronic exposure to excess arsenic in drinking water has been strongly associated with increased risks of multiple cancers, diabetes, heart disease, and reproductive and developmental problems in humans. We previously demonstrated that As, a potent endocrine disruptor at low, environmentally relevant levels, alters steroid signaling at the level of receptor-mediated gene regulation for all five steroid receptors. Objectives: The goal of this study was to determine whether As can also disrupt gene regulation via the retinoic acid (RA) receptor (RAR) and/or the thyroid hormone (TH) receptor (TR) and whether these effects are similar to previously observed effects on steroid regulation. Methods and results: Human embryonic NT2 or rat pituitary GH3 cells were treated with 0.01–5 μM sodium arsenite for 24 hr, with or without RA or TH, respectively, to examine effects of As on receptor-mediated gene transcription. At low, noncytotoxic doses, As significantly altered RAR-dependent gene transcription of a transfected RAR response element–luciferase construct and the native RA-inducible cytochrome P450 CYP26A gene in NT2 cells. Likewise, low-dose As significantly altered expression of a transfected TR response element–luciferase construct and the endogenous TR-regulated type I deiodinase (DIO1) gene in a similar manner in GH3 cells. An amphibian ex vivo tail metamorphosis assay was used to examine whether endocrine disruption by low-dose As could have specific pathophysiologic consequences, because tail metamorphosis is tightly controlled by TH through TR. TH-dependent tail shrinkage was inhibited in a dose-dependent manner by 0.1– 4.0 μM As. Conclusions: As had similar effects on RAR- and TR-mediated gene regulation as those previously observed for the steroid receptors, suggesting a common mechanism or action. Arsenic also profoundly affected a TR-dependent developmental process in a model animal system at very low concentrations. Because RAR and TH are critical for both normal human development and adult function and their dysregulation is associated with many disease processes, disruption of these hormone receptor–dependent processes by As is also potentially relevant to human developmental problems and disease risk

Gemini planet imager observational calibrations V: Astrometry and distortion

This is the final version of the article. Available from SPIE via the DOI in this record.From Conference Volume 9147: Ground-based and Airborne Instrumentation for Astronomy V, Suzanne K. Ramsay; Ian S. McLean; Hideki Takami, Montréal, Quebec, Canada, June 22, 2014We present the results of both laboratory and on sky astrometric characterization of the Gemini Planet Imager (GPI). This characterization includes measurement of the pixel scale∗ of the integral field spectrograph (IFS), the position of the detector with respect to north, and optical distortion. Two of these three quantities (pixel scale and distortion) were measured in the laboratory using two transparent grids of spots, one with a square pattern and the other with a random pattern. The pixel scale in the laboratory was also estimate using small movements of the artificial star unit (ASU) in the GPI adaptive optics system. On sky, the pixel scale and the north angle are determined using a number of known binary or multiple systems and Solar System objects, a subsample of which had concurrent measurements at Keck Observatory. Our current estimate of the GPI pixel scale is 14.14 ± 0.01 millarcseconds/pixel, and the north angle is -1.00 ± 0.03°. Distortion is shown to be small, with an average positional residual of 0.26 pixels over the field of view, and is corrected using a 5th order polynomial. We also present results from Monte Carlo simulations of the GPI Exoplanet Survey (GPIES) assuming GPI achieves ∼1 milliarcsecond relative astrometric precision. We find that with this precision, we will be able to constrain the eccentricities of all detected planets, and possibly determine the underlying eccentricity distribution of widely separated Jovians.The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). This publication makes use of data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. P.K. and J.R.G. thank support from NASA NNX11AD21G, NSF AST-0909188, and the University of California LFRP-118057. Q.M.K is a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto. The Dunlap Institute is funded through an endowment established by the David Dunlap family and the University of Toronto

Influence of eruptive style on volcanic gas emission chemistry and temperature

Gas bubbles form as magmas ascend in the crust and exsolve volatiles. These bubbles evolve chemically and physically as magma decompression and crystallization proceed. It is generally assumed that the gas remains in thermal equilibrium with the melt but the relationship between gas and melt redox state is debated. Here, using absorption spectroscopy, we report the composition of gases emitted from the lava lake of Kīlauea Volcano, Hawaii, and calculate equilibrium conditions for the gas emissions. Our observations span a transition between more and less vigorous-degassing regimes. They reveal a temperature range of up to 250 °C, and progressive oxidation of the gas, relative to solid rock buffers, with decreasing gas temperature. We suggest that these phenomena are the result of changing gas bubble size. We find that even for more viscous magmas, fast-rising bubbles can cool adiabatically, and lose the redox signature of their associated melts. This process can result in rapid changes in the abundances of redox-sensitive gas species. Gas composition is monitored at many volcanoes in support of hazard assessment but time averaging of observations can mask such variability arising from the dynamics of degassing. In addition, the observed redox decoupling between gas and melt calls for caution in using lava chemistry to infer the composition of associated volcanic gases

Stationary Black Holes: Uniqueness and Beyond

The spectrum of known black-hole solutions to the stationary Einstein equations has been steadily increasing, sometimes in unexpected ways. In particular, it has turned out that not all black-hole-equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro-vacuum black-hole spacetimes ceases to exist in self-gravitating non-linear field theories. This text aims to review some developments in the subject and to discuss them in light of the uniqueness theorem for the Einstein-Maxwell system.Comment: Major update of the original version by Markus Heusler from 1998. Piotr T. Chru\'sciel and Jo\~ao Lopes Costa succeeded to this review's authorship. Significantly restructured and updated all sections; changes are too numerous to be usefully described here. The number of references increased from 186 to 32