Gravitational Energy in Quadratic Curvature Gravities

We define the notion of energy, and compute its values, for gravitational systems involving terms quadratic in curvature. While our construction parallels that of ordinary Einstein gravity, there are significant differences both conceptually and concretely. In particular, for D=4, all purely quadratic models admit vacua of arbitrary constant curvature. Their energies, including that of conformal (Weyl) gravity, necessarily vanish in asymptotically flat spaces. Instead, they are proportional to that of the Abbott-Deser (AD) energy expression in constant curvature backgrounds and therefore also proportional to the mass parameter in the corresponding Schwarzschild-(Anti) de Sitter geometries. Combined Einstein-quadratic curvature systems reflect the above results: Absent a cosmological constant term, the only vacuum is flat space, with the usual (ADM) energy and no explicit contributions from the quadratic parts. If there is a Lambda term, then the vacuum is also unique with that Lambda value, and the energy is just the sum of the separate contributions from Einstein and quadratic parts to the AD expression . Finally, we discuss the effects on energy definition of both higher curvature terms and higher dimension.Comment: 8 pages, minor style improvements, to appear in Phys. Rev. Let

A metal dicyanamide cluster with high CO2/N2 selectivity

A new microporous metal dicyanamide cluster, Co(hmt)(dca)2 (hmt: hexamethylenetetramine, dca: dicyanamide), with accessible N-donor sites exhibits high CO2/N2 selectivity, 83 at 295 K and 1 bar, for a mixture with a 15:85 CO2 to N2 ratio. Adsorption studies show that the use of hmt and dca moieties as building blocks for solid adsorbents can enhance the CO2:surface interactions due to N atoms available inside the pores, which is confirmed by X-ray single crystal studies. © 2016 Elsevier Inc. All rights reserved

Coronary arterial anomalies in a large group of patients undergoing coronary angiography in southeast Turkey

Background: The prevalence of coronary artery anomalies (CAA) are reportedbetween 0.6–1.3% in the literature. CAA are usually asymptomatic incidental findings, but they may deteriorate coronary circulation, cause symptoms andlead to sudden cardiac death; especially in young athletes. Since interventionalprocedures are increasing rapidly for treatment of coronary artery disease (CAD) inthe modern era, comprehensive understanding of CAA is becoming progressively critical element in dealing with CAD.Materials and methods: We reviewed the database of the Cardiac Catheterisation Laboratory of Sani Konukoglu University Hospital in Gaziantep, Turkey. All patientswho were subjected to coronary angiography from 1998 to 2006 were included.Results: Among 53,655 coronary angiographies performed, CAA were foundin 653 patients (incidence of 1.21%); 590 (90.3%) patients had anomalies oforigin and distribution and 63 (11.7%) had coronary fistulae. Separate origins ofleft anterior descending (LAD) and left circumflex (LCX) coronary artery from theleft sinus of Valsalva was the most common anomaly (64.1%). Coronary arteriesbranching from anomalous aortic origin was the second most common anomaly(16.5%). Right coronary artery (RCA) originating from left sinus of Valsalva or leftmain coronary artery (LMCA) was observed in 55 (8.4%) patients, LCX arising fromRCA or right sinus of Valsalva (RSV) was seen in 52 (7.9%) patients and LMCA orLAD originating from RSV was seen in 14 (0.2%) patients. There were 16 (2.45%) patients with single coronary artery and 1 (0.15%) patient with LMCA originating from pulmonary artery.Conclusions: The incidence and the pattern of CAA in our patient population were similar with previous studies. Angiographic recognition of these vessels is importantbecause of their clinical significance and importance in patients undergoing coronary angioplasty or cardiac surgery

Burnout levels of the physical education teachers in terms of professional variablesBeden eğitimi öğretmenlerinin mesleki değişkenlere göre tükenmişlik düzeyleri

The study was undertaken in order to assess burnout levels of the physical education teachers in terms of professional variables.The population of the study was consisted of 275 physical education teachers who were employed at secondary schools and high schools of Ministry of National Education in the city center of Ordu Province during the academic year of 2012-2013. The sample of the study was composed of 163 physical education teachers who were employed at secondary schools and high schools in the city center of Ordu Province and were recruited with random sampling. As the data collection tools; Personal Information Forms and Maslach Burnout Inventory-Educators Survey Form (MBI-ES) were employed. For the data analyses; as a result of the normality tests, independent group t test was used for pairwise group comparisons whereas ANOVA and non-parametric Kruskal Wallis-H test were employed for the comparisons of the three and more groups. In light of the study results; it was determined that physical education teachers underwent “emotional burnout” for the variable of “sufficient income”.   ÖzetBu çalışma, beden eğitimi öğretmenlerinin mesleki değişkenlere göre tükenmişlik düzeylerini incelemek amacı ile yapılmıştır.Araştırmanın evrenini 2012–2013 eğitim-öğretim yılında Ordu ili (merkez) ve ilçelerinde Milli Eğitim Bakanlığına bağlı orta ve lise okullarında görev yapan 275 beden eğitimi öğretmenleri oluşturmaktadır. Örneklemini ise, Ordu ili (merkez) ve ilçelerinde görev yapan rastgele yöntemle seçilen toplam 163 beden eğitimi öğretmeni oluşturmaktadır.Araştırmada veri toplama aracı olarak, Kişisel Bilgi Formu ve Maslach Tükenmişlik Envanteri-Eğitimci Formu kullanılmıştır. Verilerin analizinde, yapılan normallik sınamasına göre ikili küme karşılaştırmaları için bağımsız grup t testi, üç veya daha fazla küme karşılaştırmaları için ANOVA non parametrik Kruskal Wallis-H testi; sonucu anlamlı bulunan farklılıkların kaynağını belirlemek üzere, varyansların homojen olmasından dolayı post hoc testlerinden Scheffe ve LSD çoklu karşılaştırma testleri kullanılmıştır. Araştırmadaki istatistiki analizler için anlamlılık düzeyi 0.05 ve 0.01 olarak ele alınmıştır. Araştırma sonucuna göre meslek gelirlerinin yeterliliği değişkeninde “duygusal tükenme” yaşadıkları belirlenmiştir

Transit timing variation analysis of the low-mass brown dwarf KELT-1 b

We investigate whether there is a variation in the orbital period of the short-period brown dwarf-mass KELT-1 b, which is one of the best candidates to observe orbital decay. We obtain 19 high-precision transit light curves of the target using six different telescopes. We add all precise and complete transit light curves from open databases and the literature, as well as the available Transiting Exoplanet Survey Satellite (TESS) observations from sectors 17 and 57, to form a transit timing variation (TTV) diagram spanning more than 10 yr of observations. The analysis of the TTV diagram, however, is inconclusive in terms of a secular or periodic variation, hinting that the system might have synchronized. We update the transit ephemeris and determine an informative lower limit for the reduced tidal quality parameter of its host star of Q ′⋆>(8.5±3.9)×106 assuming that the stellar rotation is not yet synchronized. Using our new photometric observations, published light curves, the TESS data, archival radial velocities, and broadband magnitudes, we also update the measured parameters of the system. Our results are in good agreement with those found in previous analyses

Propylthiouracil-Induced Acute Liver Failure: Role of Liver Transplantation

Propylthiouracil- (PTU-) induced hepatotoxicity is rare but potentially lethal with a spectrum of liver injury ranging from asymptomatic elevation of transaminases to fulminant hepatic failure and death. We describe two cases of acute hepatic failure due to PTU that required liver transplantation. Differences in the clinical presentation, histological characteristics, and posttransplant management are described as well as alternative therapeutic options. Frequent monitoring for PTU-induced hepatic dysfunction is strongly advised because timely discontinuation of this drug and implementation of noninvasive therapeutic interventions may prevent progression to liver failure or even death

Effective Lagrangian from Higher Curvature Terms: Absence of vDVZ Discontinuity in AdS Space

We argue that the van Dam-Veltman-Zakharov discontinuity arising in the $M^2 \to 0$ limit of the massive graviton through an explicit Pauli-Fierz mass term could be absent in anti de Sitter space. This is possible if the graviton can acquire mass spontaneously from the higher curvature terms or/and the massless limit $M^2\to 0$ is attained faster than the cosmological constant $\Lambda \to 0$. We discuss the effects of higher-curvature couplings and of an explicit cosmological term ($\Lambda$) on stability of such continuity and of massive excitations.Comment: 23 pages, Latex, the version to appear in Class. Quant. Gra