Forward modelling of brightness variations in Sun-like stars I. Emergence and surface transport of magnetic flux

The latitudinal distribution of starspots deviates from the solar pattern with increasing rotation rate. Numerical simulations of magnetic flux emergence and transport can help model the observed stellar activity patterns and the associated brightness variations. We set up a composite model for the processes of flux emergence and transport on Sun-like stars, to simulate stellar brightness variations for various levels of magnetic activity and rotation rates. Assuming that the distribution of magnetic flux at the base of the convection zone follows solar scaling relations, we calculate the emergence latitudes and tilt angles of bipolar regions at the surface for various rotation rates, using thin-flux-tube simulations. Taking these two quantities as input to a surface flux transport SFT model, we simulate the diffusive-advective evolution of the radial field at the stellar surface, including effects of active region nesting. As the rotation rate increases, (1) magnetic flux emerges at higher latitudes and an inactive gap opens around the equator, reaching a half-width of $20^\circ$ for $8\Omega_\odot$, (2) the tilt angles of freshly emerged bipolar regions show stronger variations with latitude. Polar spots can form at $8\Omega_\odot$ by accumulation of follower-polarity flux from decaying bipolar regions. From $4\Omega_\odot$ to $8\Omega_\odot$, the maximum spot coverage changes from 3 to 20%, respectively, compared to 0.4% for the solar model. Nesting of activity can lead to strongly non-axisymmetric spot distributions. On Sun-like stars rotating at $8\Omega_\odot$ ($P_{\rm rot}\simeq 3$ days), polar spots can form, owing to higher levels of flux emergence rate and tilt angles. Defining spots by a threshold field strength yields global spot coverages that are roughly consistent with stellar observations.Comment: 16 pages, 13 figures. Astron. & Astrophys. (in press); minor language corrections mad

The Investigation of Surplus of Energy and Signal Propagation at Time-Domain Waveguide Modes

Classical waveguide theory has been developed bearing on Bernoulli’s product method which results in separation of space and time variables in Maxwell’s equations. The time-harmonic waveguide modes have been stated mathematically for transmitting signals along the waveguides. As a starting point, present studies on transverse-electric (TE) and transverse-magnetic (TM) waveguide modes with previous results are taken and exhibited in an advanced form. They have been obtained within the framework of an evolutionary approach to solve Maxwell’s equations with time derivative. As a result every modal field is obtained in the form of a product of vector functions of transverse coordinates and modal amplitudes. The modal amplitudes which are the functions of axial coordinate z and time t are the central matter of this study. The amplitudes are generated by a potential which is governing by Klein-Gordon equation (KGE). The KGE has remarkable properties of symmetry which has great importance in our analytical studies of the transient modes. Ultimately, in this study, a time-domain waveguide problem is solved analytically in accordance with the causality principle. Moreover, the graphical results are shown for the case when the energy and surplus of the energy for the time-domain waveguide modes are represented via Airy functions

First Chromospheric Activity and Doppler Imaging Study of PW And Using a New Doppler Imaging Code: SpotDIPy

Measuring coverage of dark spots on cool stars is important in understanding how stellar magnetic activity scales with the rotation rate and convection zone depth. In this respect, it is crucial to infer surface magnetic patterns on G and K stars, to reveal solar-like stellar dynamos in action. Molecular bands serve as invaluable indicators of cool spots on the surfaces of stars, as they play a crucial role in enabling accurate assessments of the extent of spot coverage across the stellar surface. Therefore, more reliable surface images can be obtained considering the inversion of atomic lines with molecular bands. In this context, we simultaneously carry out Doppler imaging (DI) using atomic lines as well as Titanium Oxide (TiO) band profiles of PW And (K2 V) and also investigate chromospheric activity indicators for the first time in the literature, using the high-resolution spectra. The surface spot distribution obtained from the inversion process represents both atomic line and TiO-band profiles quite accurately. The chromospheric emission is also correlated with photospheric spot coverage, except during a possible flare event during the observations. We detect frequent flare activity, using TESS photometry. We also introduce a new open-source, Python-based DI code SpotDIPy that allows performing surface reconstructions of single stars using the maximum entropy method. We test the code by comparing surface reconstruction simulations with the extensively used DoTS code. We show that the surface brightness distribution maps reconstructed via both codes using the same simulated data are consistent with each other.Comment: Accepted for publication by the Astrophysical Journa

Türkiye'de koroner yoğun bakım ünitelerindeki hastane içi mortalite (MORCOR-TURK) çalışmasında hasta temel karakteristikleri ve öngördürücüleri

OBJECTIVE: The MORtality in CORonary Care Units in Türkiye (MORCOR-TURK) trial is a national registry evaluating predictors and rates of in-hospital mortality in coronary care unit (CCU) patients in Türkiye. This report describes the baseline demographic characteristics of patients recruited for the MORCOR-TURK trial. METHODS: The study is a multicenter, cross-sectional, prospective national registry that included 50 centers capable of 24-hour CCU service, selected from all seven geographic regions of Türkiye. All consecutive patients admitted to CCUs with cardiovascular emergencies between September 1-30, 2022, were prospectively enrolled. Baseline demographic characteristics, admission diagnoses, laboratory data, and cardiovascular risk factors were recorded. RESULTS: A total of 3,157 patients with a mean age of 65 years (range: 56-73) and 2,087 (66.1%) males were included in the analysis. Patients with arterial hypertension [1,864 patients (59%)], diabetes mellitus (DM) [1,184 (37.5%)], hyperlipidemia [1,120 (35.5%)], and smoking [1,093 (34.6%)] were noted. Non-ST elevation myocardial infarction (NSTEMI) was the leading cause of admission [1,187 patients (37.6%)], followed by ST elevation myocardial infarction (STEMI) in 742 patients (23.5%). Other frequent diagnoses included decompensated heart failure (HF) [339 patients (10.7%)] and arrhythmia [272 patients (8.6%)], respectively. Atrial fibrillation (AF) was the most common pathological rhythm [442 patients (14%)], and chest pain was the most common primary complaint [2,173 patients (68.8%)]. CONCLUSION: The most common admission diagnosis was acute coronary syndrome (ACS), particularly NSTEMI. Hypertension and DM were found to be the two leading risk factors, and AF was the most commonly seen pathological rhythm in all hospitalized patients. These findings may be useful in understanding the characteristics of patients admitted to CCUs and thus in taking precautions to decrease CCU admissions

The frequency of Duchenne muscular dystrophy/Becker muscular dystrophy and Pompe disease in children with isolated transaminase elevation: results from the observational VICTORIA study

IntroductionElevated transaminases and/or creatine phosphokinase can indicate underlying muscle disease. Therefore, this study aims to determine the frequency of Duchenne muscular dystrophy/Becker muscular dystrophy (DMD/BMD) in male children and Pompe disease (PD) in male and female children with isolated hypertransaminasemia.MethodsThis multi-center, prospective study enrolled patients aged 3–216 months with serum alanine transaminase (ALT) and/or aspartate transaminase (AST) levels >2× the upper limit of normal (ULN) for ≥3 months. Patients with a known history of liver or muscle disease or physical examination findings suggestive of liver disease were excluded. Patients were screened for creatinine phosphokinase (CPK) levels, and molecular genetic tests for DMD/BMD in male patients and enzyme analysis for PD in male and female patients with elevated CPK levels were performed. Genetic analyses confirmed PD. Demographic, clinical, and laboratory characteristics of the patients were analyzed.ResultsOverall, 589 patients [66.8% male, mean age of 63.4 months (standard deviation: 60.5)] were included. In total, 251 patients (188 male and 63 female) had CPK levels above the ULN. Of the patients assessed, 47% (85/182) of male patients were diagnosed with DMD/BMD and 1% (3/228) of male and female patients were diagnosed with PD. The median ALT, AST, and CPK levels were statistically significantly higher, and the questioned neurological symptoms and previously unnoticed examination findings were more common in DMD/BMD patients than those without DMD/BMD or PD (p < 0.001).DiscussionQuestioning neurological symptoms, conducting a complete physical examination, and testing for CPK levels in patients with isolated hypertransaminasemia will prevent costly and time-consuming investigations for liver diseases and will lead to the diagnosis of occult neuromuscular diseases. Trial RegistrationClinicaltrials.gov NCT04120168

Hans Hofmann'ın Resmin Doğası ve Yapısına İlişkin Anlayışı

<p>Amerikan sanatına yön veren öncü sanatçı ve eğitimci Hans Hofmann, Almanya'dan sonra New York ve Provincetown'da dersler vererek soyut ifadecilik akımının gelişimine katkı sağlamıştır. Sanatın kökeninin doğada yattığını savunur ve doğadan ilham alır. Hofmann, fiziksel dünya varlıklarını soyutlayarak temel şekillerle ifade eder. Sanatını doğanın enerjisi ve hareketiyle ilişkilendirirken, her sanat eserini duyusal deneyimler yoluyla ifade edilen bir konu olarak görür. Hofmann, öğrencilerine yüzlerce kişiye öğretmenlik yaparak sanatı öğretmiş ve onun için sanatçının özgül yeteneklerinin doğuştan geldiğini savunmuştur. Malzemelerin doğası ve araçların kullanımı sanat eserlerinin ifadesini belirler. Hofmann'ın sanatı, renk, form ve hareketin birbirini etkilediği bir sistem olarak düşünülür. Resimde pozitif ve negatif yüzeyler arasındaki ilişkisi ve boşlukların önemi üzerinde durur. İtme ve çekme kavramı (push and pull), resmin derinliğini ve etkisini oluşturan temel bir prensibini renk, formu şekillendirerek resimsel öğelerin birbirleriyle etkileşimini vurgular. Sanat ve metafizik gerçeklik ilişkisini kurar ve ressamın tinsel gerçekliği duyusal deneyimlerle ifade ettiğini savunur. Hofmann'ın sanat anlayışı, resimde doğa, enerji, renk ve ilişki üzerine derin bir felsefi yaklaşımı kendinden sonraki sanatçılarabir ilham oluşturur.</p><p>Hans Hofmann, a pioneering artist and educator who shaped American art, contributed to the development of the abstract expressionism movement by giving lectures in New York and Provincetown after Germany. He argues that the origin of art lies in nature and is inspired by nature. Hofmann abstracts the physical world entities and expresses them with basic shapes. While he associates his art with the energy and movement of nature, he sees each work of art as a subject expressed through sensory experiences. Hofmann taught art by teaching hundreds of his students and argued that the artist's specific talents were innate. The nature of materials and the use of tools determine the expression of works of art. Hofmann's art is considered as a system in which color, form and movement influence each other. It focuses on the relationship between positive and negative surfaces and the importance of spaces in painting. The concept of push and pull emphasizes the interaction of pictorial elements with each other by shaping color and form, a basic principle that creates the depth and effect of painting. He establishes the relationship between art and metaphysical reality and argues that the painter expresses spiritual reality through sensory experiences. Hofmann's understanding of art and his deep philosophical approach to nature, energy, color and relationship in painting inspire the artists who came after him.  </p&gt

Kuram ve pratik: Antik Yunan kentlerinde ızgara-plan gelişiminin sosyo-politik ve felsefi dinamikleri

Social, political and philosophical dynamics which supposedly played an important role in the formation of the grid-plan in ancient Greek cities are explored in this thesis. In this respect, the thesis aims to expose the socio-political and philosophical matrix of Greek society in which the grid was implemented with an emphasis on the concepts of “equality,” “rationality” and “geometric harmony.” Having formulated a theoretical framework, it concentrates on several cases from different regions and contexts in the Mediterranean in order to confirm this framework. The thesis investigates the nature of the Greek grid-plan within three main parts; first the grid-plans of non-Greek cultures with which ancient Greeks had close contacts; second the relationship between the grid-plan and political power in Greek poleis with special attention to the formation of ‘egalitarian’ ideals in society; third the physical expressions of the philosophical concepts of “perfection,” “mathematical regularity” and “geometrical equality” in the cosmos on urban pattern.M.A. - Master of Art

“Voiced at Lale Film Studios”: An Interview with Necip Sarıcı on Dubbing in Turkish Cinema

Necip Sarıcı, Türk Sinemasının en önemli isimlerinden biridir. 1949 yılında, henüz on beş yaşındayken, makinist çırağı olarak girdiği sinemaya yetmiş yılı aşkın süredir hizmet etmeye devam etmektedir. Üç yüz elliden fazla filmi seslendirmiş, bu filmlerin seslerini kaydetmiş ya da ses mühendisi olarak altyapısını düzenlemiştir. Bunun yanı sıra yapımcılık ve yönetmenlik koltuklarına da oturmuştur. 1979 yılında Lale Film’i satın alarak değerli arşivinin korunmasını sağlamıştır. Bu görüşme hem Sarıcı’nın zengin geçmişine hem de onun anlatımıyla Türk Sinemasında seslendirmenin yolculuğuna odaklanmaktadır.Necip Sarıcı is one of the most important names of Turkish Cinema. He entered the cinema as a machinist’s apprentice in 1949, when he was only fifteen years old, and has been serving for more than seventy years. He has voiced more than three hundred and fifty films, recorded the sounds of these films or arranged the infrastructure of films as a sound engineer. In addition, he has also sat in the production and directing chairs. By purchasing Lale Film in 1979, he has ensured the preservation of its valuable archive. This interview focuses on both Sarıcı’s rich past and the journey of voice acting in Turkish Cinema with his narration

“Lale Film Stüdyolarında Seslendirilmiştir”: Necip Sarıcı ile Türk Sinemasında Seslendirme Üzerine Bir Görüşme

Necip Sarıcı, Türk Sinemasının en önemli isimlerinden biridir. 1949 yılında, henüz on beş yaşındayken, makinist çırağı olarak girdiği sinemaya yetmiş yılı aşkın süredir hizmet etmeye devam etmektedir. Üç yüz elliden fazla filmi seslendirmiş, bu filmlerin seslerini kaydetmiş ya da ses mühendisi olarak altyapısını düzenlemiştir. Bunun yanı sıra yapımcılık ve yönetmenlik koltuklarına da oturmuştur. 1979 yılında Lale Film’i satın alarak değerli arşivinin korunmasını sağlamıştır. Bu görüşme hem Sarıcı’nın zengin geçmişine hem de onun anlatımıyla Türk Sinemasında seslendirmenin yolculuğuna odaklanmaktadır