Finite Larmor Radius Effects on Weakly Magnetized, Dilute Plasmas

We investigate the stability properties of a hot, dilute and differentially rotating weakly magnetized plasma which is believed to be found in the interstellar medium of galaxies and protogalaxies and in the low-density accretion flows around some giant black holes like the one in the Galactic center. In the linear MHD regime, we consider the combined effects of gyroviscosity and parallel viscosity on the magnetorotational instability. The helical magnetic field is considered in the investigation. We show that the gyroviscous effect and the pitch angles cause a powerful gyroviscous instability. Furthermore, in most of the cases, plasma with the above mentioned properties is unstable and the growth rates of the unstable modes are larger than that of the magnetorotational instability.Comment: 7 pages, 4 figures. Accepted for publication in MNRA

A mean field dynamo from negative eddy diffusivity

Using direct numerical simulations, we verify that "flow IV" of Roberts (1972) exhibits dynamo action dominated by horizontally averaged large-scale magnetic field. With the test-field method we compute the turbulent magnetic diffusivity and find that it is negative and overcomes the molecular diffusivity, thus explaining quantitatively the large-scale dynamo for magnetic Reynolds numbers above $\approx8$. As expected for a dynamo of this type, but contrary to $\alpha$-effect dynamos, the two horizontal field components grow independently of each other and have arbitrary amplitude ratios and phase differences. Small length scales of the mean magnetic field are shown to be stabilized by the turbulent magnetic diffusivity becoming positive at larger wavenumbers. Oscillatory decaying or growing solutions have also been found in certain wavenumber intervals and sufficiently large values of the magnetic Reynolds number. For magnetic Reynolds numbers below $\approx0.5$ the turbulent magnetic diffusivity is confirmed to be positive, as expected for all incompressible flows. Earlier claims of a dynamo driven by a modified Taylor-Green flow through negative eddy diffusivity could not be confirmed.Comment: 7 pages, 9 figures, accepted to MNRA

The Rossiter-McLaughlin effect and analytic radial velocity curves for transiting extrasolar planetary systems

A transiting extrasolar planet sequentially blocks off the light coming from the different parts of the disk of the host star in a time dependent manner. Due to the spin of the star, this produces an asymmetric distortion in the line profiles of the stellar spectrum, leading to an apparent anomaly of the radial velocity curves, known as the Rossiter - McLaughlin effect. Here, we derive approximate but accurate analytic formulae for the anomaly of radial velocity curves taking account of the stellar limb darkening. The formulae are particularly useful in extracting information of the projected angle between the planetary orbit axis and the stellar spin axis, \lambda, and the projected stellar spin velocity, V sin I_s. We create mock samples for the radial curves for the transiting extrasolar system HD209458, and demonstrate that constraints on the spin parameters (V sin I_s, \lambda) may be significantly improved by combining our analytic template formulae and the precision velocity curves from high-resolution spectroscopic observations with 8-10 m class telescopes. Thus future observational exploration of transiting systems using the Rossiter - McLaughlin effect is one of the most important probes to better understanding of the origin of extrasolar planetary systems, especially the origin of their angular momentum.Comment: 39 pages, 16 figures, Accepted to ApJ. To match the published version (ApJ 623, April 10 issue

Perspective of turkish medicine students on cancer, cancer treatments, palliative care, and oncologists (ares study): A study of the palliative care working committee of the turkish oncology group (TOG)

Cancer is one of the most common causes of death all over the World (Rahib et al. in Cancer Res 74(11):2913–2921, 2014; Silbermann et al. in Ann Oncol 23(Suppl 3):iii15–iii28, 2012). It is crucial to diagnose this disease early by effective screening methods and also it is very important to acknowledge the community on various aspects of this disease such as the treatment methods and palliative care. Not only the oncologists but every medical doctor should be educated well in dealing with cancer patients. Previous studies suggested various opinions on the level of oncology education in medical schools (Pavlidis et al. in Ann Oncol 16(5):840–841, 2005). In this study, the perspectives of medical students on cancer, its treatment, palliative care, and the oncologists were analyzed in relation to their educational status. A multicenter survey analysis was performed on a total of 4224 medical school students that accepted to enter this study in Turkey. After the questions about the demographical characteristics of the students, their perspectives on the definition, diagnosis, screening, and treatment methods of cancer and their way of understanding metastatic disease as well as palliative care were analyzed. The questionnaire includes questions with answers and a scoring system of Likert type 5 (absolutely disagree = 1, completely agree = 5). In the last part of the questionnaire, there were some words to detect what the words “cancer” and “oncologist” meant for the students. The participant students were analyzed in two study groups; “group 1” (n = 1.255) were phases I and II students that had never attended an oncology lesson, and “group 2” (n = 2.969) were phases III to VI students that had attended oncology lessons in the medical school. SPSS v17 was used for the database and statistical analyses. A value of p < 0.05 was noted as statistically significant. Group 1 defined cancer as a contagious disease (p = 0.00025), they believed that early diagnosis was never possible (p = 0.042), all people with a diagnosis of cancer would certainly die (p = 0.044), and chemotherapy was not successful in a metastatic disease (p = 0.003) as compared to group 2. The rate of the students that believed gastric cancer screening was a part of the national screening policy was significantly more in group 1 than in group 2 (p = 0.00014). Group 2 had a higher anxiety level for themselves or their family members to become a cancer patient. Most of the students in both groups defined medical oncologists as warriors (57% in group 1 and 40% in group 2; p = 0.097), and cancer was reminding them of “death” (54% in group 1 and 48% in group 2; p = 0.102). This study suggested that oncology education was useful for the students’ understanding of cancer and related issues; however, the level of oncology education should be improved in medical schools in Turkey. This would be helpful for medical doctors to cope with many aspects of cancer as a major health care problem in this country. © 2018, American Association for Cancer Education

On the aorist in conditional antecedents

This paper aims to render an explanation for the interpretations of the Turkish aorist when it occurs at the antecedent clause of a conditional. I argue that at the main predicate position the aorist marker has two main interpretations, namely the future-oriented and the characterizing ones. However, inside the antecedent clause, these readings are not readily accessible in the way that they are at the consequent clause, i.e., the main predicate of the conditional. I tackle this situation from two different perspectives and layout two proposals. Based on Kratzer’s (1986, 1991) well-known restrictor analysis of conditionals, my first proposal is that the aorist marker is licensed in the antecedent clause only if the consequent clause has one of its matrix clause interpretations. Nonetheless, various examples allow the aorist marker in the antecedent even though the consequent clause has neither the future-oriented nor the characterizing interpretations. Therefore, I change my approach and make a final proposal that satisfactorily describes both the cases that conform to my initial proposal and the ones that do not. I propose that the aorist in the antecedent either sets the evaluation time of the consequent to the future, in line with Schulz’s (2008) analysis or makes a quantification over situations, as von Fintel (1994) argues for.

A Formal Methods Approach to Pattern Synthesis in Reaction Diffusion Systems

We propose a technique to detect and generate patterns in a network of locally interacting dynamical systems. Central to our approach is a novel spatial superposition logic, whose semantics is defined over the quad-tree of a partitioned image. We show that formulas in this logic can be efficiently learned from positive and negative examples of several types of patterns. We also demonstrate that pattern detection, which is implemented as a model checking algorithm, performs very well for test data sets different from the learning sets. We define a quantitative semantics for the logic and integrate the model checking algorithm with particle swarm optimization in a computational framework for synthesis of parameters leading to desired patterns in reaction-diffusion systems

Haseki Hürrem Sultan Group of Buldings Restoration of the Yaers

Kanuni Sultan Süleyman’nın hasekisi Hürrem Sultan’ın banisi olduğu Haseki Hürrem Sultan Külliyesi, Bizans döneminde Kuru Tepe/Kserolofos/Xerolophos daha sonra Avrat/Avret Pazarı olarak adlandırılan İstanbul’un önemli bir bölgesinde inşa edilmiştir. Haseki Hürrem Sultan Külliyesi, Osmanlı İmparatorluğu’nun sosyal, ekonomik, siyasal olgunluğa eriştiği dönemin yapı alanının en önemli mimarı Mimar Sinan’ın (1489 1588) eseridir. Haseki Camisi, Sinan’ın, 1538’de mimarbaşı olduktan sonra inşa ettiği ilk kagir, kubbeli camidir. Külliyede camiden başka medrese, mektep, imaret ve darüşşifa bulunur. İmaret dışındaki yapılar Sinan’a ait tezkerelerde yer almaktadır. Haseki Külliyesi, yapımından günümüze geçirdiği çok sayıda afet sonrasında onarıma tabi tutulmuştur. Haseki Hürrem Sultan Külliyesi’ne ait bu makalede, Cami ve Ahşap Meşruta dışındaki Medrese, Sıbyan Mektebi, İmaret ve Darrüşifa’da gerçekleştirilen onarımlara yer verilecek, 2010-2102 restorasyonu ayrıntılı olarak ele alınacaktır