519 research outputs found
Impulsive gravitational waves in general massive 3D gravity
Impulsive, non-diverging, Petrov-Segre type N gravitational wave solutions to
a general massive three-dimensional gravity in the de Sitter, anti-de Sitter
and flat Minkowski backgrounds are constructed in a unified manner by using the
exterior algebra of differential forms.Comment: Published versio
Design of a tunable multi-band differential LC VCO using 0.35 mu m SiGe BiCMOS technology for multi-standard wireless communication systems
In this paper, an integrated 2.2-5.7GHz multi-band differential LC VCO for multi-standard wireless communication systems was designed utilizing 0.35 mu m SiGe BiCMOS technology. The topology, which combines the switching inductors and capacitors together in the same circuit, is a novel approach for wideband VCOs. Based on the post-layout simulation results, the VCO can be tuned using a DC voltage of 0 to 3.3 V for 5 different frequency bands (2.27-2.51 GHz, 2.48-2.78 GHz, 3.22-3.53 GHz, 3.48-3.91 GHz and 4.528-5.7 GHz) with a maximum bandwidth of 1.36 GHz and a minimum bandwidth of 300 MHz. The designed and simulated VCO can generate a differential output power between 0.992 and -6.087 dBm with an average power consumption of 44.21 mW including the buffers. The average second and third harmonics level were obtained as -37.21 and -47.6 dBm, respectively. The phase noise between -110.45 and -122.5 dBc/Hz, that was simulated at 1 MHz offset, can be obtained through the frequency of interest. Additionally, the figure of merit (FOM), that includes all important parameters such as the phase noise, the power consumption and the ratio of the operating frequency to the offset frequency, is between -176.48 and -181.16 and comparable or better than the ones with the other current VCOs. The main advantage of this study in comparison with the other VCOs, is covering 5 frequency bands starting from 2.27 up to 5.76 GHz without FOM and area abandonment. Output power of the fundamental frequency changes between -6.087 and 0.992 dBm, depending on the bias conditions (operating bands). Based on the post-layout simulation results, the core VCO circuit draws a current between 2.4-6.3 mA and between 11.4 and 15.3 mA with the buffer circuit from 3.3 V supply. The circuit occupies an area of 1.477 mm(2) on Si substrate, including DC, digital and RF pads
Central form of multiple symmetric lipomatosis: a case report
Multiple symmetric lipomatosis (also known as Madelung's disease, Launois-Bensaude syndrome or benign symmetric lipomatosis) is a rare disease, the etiology of which is unknown. Multiple, symmetric, non-encapsulated lipomatous masses on the face, neck, upper arms, and upper trunk are typical in most cases. Five out of the 200 cases reported in the literature were the distal form of the disease; the rest were proximal. We describe, for the first time, a central form of the disease, simultaneously involving the lower trunk, arms and upper legs
Creative information services at the public libraries of Istanbul
Today, when the library using habits decrease day by day, public libraries need to adapt to daily shifting conditions in order to reach their aims and continue their existences. If public libraries could foresee the changes and start them, they would be the Avant-garde institutions of their societies. Within this context, it is very important for public library staff, particularly the executors and librarians, to generate innovation by uncovering their creative energies. Defined as the producing originality in a field, creativity exists in every person and is a perfectible feature. It is possible to say that the individual, organization and society to be beneficial by treating the created innovations and converting them into society’s benefit. Undoubtedly, it can be provided via public libraries’ creative, innovative and entrepreneur organizational structure and operation. In this study, creativity is analyzed by searching answers for the question why public libraries should canalize to creative services. Additionally, by addressing to Istanbul’s situation, examples of the creative information services held at the public libraries of Istanbul is presented
SEMI-STRUCTURED PROBLEM POSING ABILITIES OF PROSPECTIVE PRIMARY SCHOOL TEACHERS: A CASE OF TURKEY
The purpose of this case study is to examine the problems that prospective primary school teachers posed related to the basic mathematical operations with whole numbers and to determine their problem posing abilities. The data was collected from seventy-two prospective primary school teachers through the Semi-Structured Problem Posing Questionnaire consisting of two questions. The descriptive analysis approach was used to analyze the data. According to the findings of the study, some prospective primary school teachers posed problems, which are not suitable to the learning outcomes. Additionally, some of them posed problems with lack of information due to having difficulty in analyzing and discovering the mathematical situation in the problem posing situation. On the other hand, the types of solvable problems were join and separate problems, especially, result unknown problems. State differently, prospective teachers had a tendency towards posing easiest and low level problems. Article visualizations
Ahmet Hilmi Koğî’nin “er-Risâletu’l-Hilmiyye fî’l- Kavâ‘idi’l-Vad‘iyye” Adlı Risalesinin Haşiyesiyle Birlikte Edisyon Kritiği
Ahmet Hilmi Koğî (ö. 1996), Şark medrese geleneğinin önemli simalarından biridir. Koğî, Medrese hayatından sonra imamlık göreviyle birlikte tedrisat faaliyetlerinde bulundu. Aynı zamanda iyi bir hattat da olan Koğî, tarihin tozlu raflarında kalmış onlarca eseri istinsah edip tashih, tahkik ve tahlil etti. Üretken bir âlim olan Koğî, gramer, fıkıh, tefsir, tecvit, münazara, mantık, itikat ve vad‘ gibi temel İslam bilimlerinin farklı ilim dallarında birçok eser kaleme aldı. Koğî’nin Arap diliyle alakalı birçok risalesi bulunmaktadır. Bu risalelerinden biri de er-Risâletu’l-Hilmiyye fi’l-Kavâ‘idi’l-Vad‘iyye adlı çalışmasıdır. İlim dünyasında pek de bilinmeyen bu risâlede Arap dilinde vad‘ ilmiyle alakalı kurallar ele alınmıştır. Koğî, dile getirdiği vad‘ ilmine dair kuralların daha iyi anlaşılması için bu risâlesine bir haşiye kaleme almıştır. Elimizdeki nüsha müellifin kendi el yazısı olup metin üstte haşiye altta olacak şekilde yazılmıştır. Buna ilaveten hem metnin hem de haşiyenin kenarlarında yer yer ta‘likler de mevcuttur. Edisyon kritiğinden ibaret olan bu çalışmayla, Koğî’nin bu veciz çalışmasını ilgililerin istifadesine sunmak ve böylece ilim dünyasına bir katkıda bulunmak gaye edinilmiştir. Bu çerçevede çalışmanın girişinde ana hatlarıyla vad‘ ilmi ele alınmıştır. Ardından özet bir şekilde Koğî’nin hayatı ve eserlerine değinilmiş ve muhteva ve kaynakları açısından risâlenin tahlili yapılarak tahkiki gerçekleştirilmiştir
4842 SAYILI YASA IŞIĞINDA YATIRIM İNDİRİMİ UYGULAMASI
Yatırım İndirimi istisnası, ticari ve zirai kazançlar ile kurum kazançlarının vergilendirilmesinde, kanunda öngörülen şartlar dahilinde , yapılan harcamaların belli bir tutarının vergiye tabi matrahın hesabında indirilmesine imkan tanıyan bir teşvik sistemidir.Bu özelliğiyle yatırım indirimi , yatırımın maliyetine etkide bulunarak yatırımın karlılığınıartıran bir teşvik sistemidir. 4842 sayılıyasa ile yatırım indirimi uygulamasına önemli değişiklikler getirilmiştir. İlk değişiklik ise yatırım indiriminin bir istisna olduğunun kanun metninde yer almasıolmuştur
Superior mesenteric artery syndrome causing growth retardation
Superior mesenteric artery syndrome is a rare and lifethreateningclinical condition caused by the compressionof the third portion of the duodenum between the aortaand the superior mesenteric artery’s proximal part. Thiscompression may lead to chronic intermittent, acute totalor partial obstruction. Sudden weight-loss and the relateddecrease in the fat tissue are considered to be the etiologicalreason of acute stenosis. Weight-loss accompaniedby nausea, vomiting, anorexia, epigastric pain, andbloating are the leading complaints. Barium radiographs,computerized tomography, conventional angiography,tomographic and magnetic resonance angiography areused in the diagnosis. There are medical and surgical approachesto treatment. We hereby present the case ofa patient with superior mesenteric artery syndrome withdelayed diagnosis.Key words: superior mesenteric artery syndrome, nausea-vomiting, anorexi
ESCADA: Efficient Safety and Context Aware Dose Allocation for Precision Medicine
Finding an optimal individualized treatment regimen is considered one of the
most challenging precision medicine problems. Various patient characteristics
influence the response to the treatment, and hence, there is no
one-size-fits-all regimen. Moreover, the administration of an unsafe dose
during the treatment can have adverse effects on health. Therefore, a treatment
model must ensure patient \emph{safety} while \emph{efficiently} optimizing the
course of therapy. We study a prevalent medical problem where the treatment
aims to keep a physiological variable in a safe range and preferably close to a
target level, which we refer to as \emph{leveling}. Such a task may be relevant
in numerous other domains as well. We propose ESCADA, a novel and generic
multi-armed bandit (MAB) algorithm tailored for the leveling task, to make
safe, personalized, and context-aware dose recommendations. We derive high
probability upper bounds on its cumulative regret and safety guarantees.
Following ESCADA's design, we also describe its Thompson sampling-based
counterpart. We discuss why the straightforward adaptations of the classical
MAB algorithms such as GP-UCB may not be a good fit for the leveling task.
Finally, we make \emph{in silico} experiments on the bolus-insulin dose
allocation problem in type-1 diabetes mellitus disease and compare our
algorithms against the famous GP-UCB algorithm, the rule-based dose
calculators, and a clinician.Comment: 23 pages, 12 figure
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