53 research outputs found
Bachian Gravity in Three Dimensions
In three dimensions, there exist modifications of Einstein's gravity akin to
the topologically massive gravity that describe massive gravitons about
maximally symmetric backgrounds. These theories are built on the
three-dimensional version of the Bach tensor (a curl of the Cotton-York tensor)
and its higher derivative generalizations; and they are on-shell consistent
without a Lagrangian description based on the metric tensor alone. We give a
generic construction of these models, find the spectra and compute the
conserved quantities for the Banados-Teitelboim-Zanelli black hole.Comment: 17 pages, a note added on MM
The Kerr-Schild Double Copy in Lifshitz Spacetime
The Kerr-Schild double copy is a map between exact solutions of general
relativity and Maxwell's theory, where the nonlinear nature of general
relativity is circumvented by considering solutions in the Kerr-Schild form. In
this paper, we give a general formulation, where no simplifying assumption
about the background metric is made, and show that the gauge theory source is
affected by a curvature term that characterizes the deviation of the background
spacetime from a constant curvature spacetime. We demonstrate this effect
explicitly by studying gravitational solutions with non-zero cosmological
constant. We show that, when the background is flat, the constant charge
density filling all space in the gauge theory that has been observed in
previous works is a consequence of this curvature term. As an example of a
solution with a curved background, we study the Lifshitz black hole with two
different matter couplings. The curvature of the background, i.e., the Lifshitz
spacetime, again yields a constant charge density; however, unlike the previous
examples, it is canceled by the contribution from the matter fields. For one of
the matter couplings, there remains no additional non-localized source term,
providing an example for a non-vacuum gravity solution corresponding to a
vacuum gauge theory solution in arbitrary dimensions.Comment: 20 pages + references, a reference regarding the KS form of the
Lifshitz black holes adde
Regularized Weyl double copy
We propose a regularization procedure in the sourced Weyl double copy, a
spinorial version of the classical double copy, such that it matches much more
general results in the Kerr-Schild version. In the regularized Weyl double
copy, the AdS and the Lifshitz black holes, which form the basis of the study
of strongly coupled gauge theories at finite temperature through the AdS/CFT
correspondence and its non-relativistic generalization, become treatable. We
believe that this might pave the way for finding out a relation between the
classical double copy and holograpy.Comment: Minor change
The impact of hybrid capture-based comprehensive genomic profiling on treatment strategies in patients with solid tumors
Objective: The development of bioinformatics and comprehensive genomic profiling (CGP) has provided insights into the ap-plicability and functionality of the genomic alterations (GA). In this study, we evaluated the impact of CGP on the treatment plan and outcomes in a significant number of patients. Material and Methods: We carried out a retrospective case-control study on 164 adult patients with advanced solid tumors from 15 oncology centers in Türkiye. Results: In all cases, CGP was performed within 23.8 [standard deviation (SD)±32.1] months of initial diagnosis. Non-small cell lung carcinoma, breast cancer, unknown primary carcinoma, colorectal carcinoma, and sarcoma were among the most common tumor types, accounting for 61.5% of all cases. CGP was performed immediately after the diagnosis of advanced cancer in 13 patients (7.9%). In 158 patients (96.4%), at least one GA was found as per the CGP report. Also, in the reports, the average tumor mutational burden (TMB) and GAs were 7.3 (SD±8.7) mut/Mb and 3.5 (SD±2.0), respectively. According to CGP reports, 58 patients had 79 evidence-based drug suggestions for their particular tumor type, whereas 97 patients had 153 evidence-based drug suggestions for another tumor type. After the primary oncologist interpreted the CGP reports, significant changes were made to the treatment of 35 (21.3%) patients. Conclusion: We strongly believe that in the future, high-TMB or other tumor-agnostic biomarkers will become much more afford-able, and CGP will serve as one of the major decision-making tools for the treatment of patients along with pathological, radiological or lab-oratory tests
Üç boyutta Bachian kütle çekimi
Modified theories in 3-dimensions such as the topologically massive gravity (TMG), new massive gravity (NMG) or Born-Infeld extension of NMG arise from the vari-ations of diffeomorphism invariant actions; hence the resulting field equations aredivergence free. Namely, the rank two tensor defining the field equations satisfy aBianchi identity for all smooth metrics. However there are some recently constructedtheories that do not identically satisfy Bianchi identities for all metrics, but only forthe solutions of the theory. These are called on-shell consistent theories of whichexamples are the minimal massive gravity (MMG) and the exotic massive gravity(EMG). We work out the generic on-shell consistent model in 3-dimensions as amodified Einstein gravity theory which is based on the analog of the Bach tensor,hence we name it as the Bachian gravity. Conserved charges are found by using thelinearization about maximally symmetric backgrounds for the Bañados-Teitelboim-Zanelli (BTZ)-black hole metric. It is complicated to solve the field equations of thegravity theory and hence very few solutions with only maximal symmetry are known. We use the projection formalism to obtain a reduction of the some relevant 2-tensorsdefining the field equations with the help of the Geroch’s reduction method.Thesis (Ph.D.) -- Graduate School of Natural and Applied Sciences. Physics
Dalış sertifikasyonu eğitim programında scuba dalıcılarında görülen temporomandibuler bozukluklar
WOS: 000311889300114PubMed ID: 23147349The design of a diving regulator's mouthpiece increases the risk of a temporomandibular disorder (TMD) in scuba divers. The total weight of a diving regulator is reflected directly on the temporomandibular joint, causing articular and periarticular disorders. In the current study, the prevalence of TMD in scuba divers triggered during diving certification training is investigated. We also aimed to determine the factors that lead to TMD during diving training and clarify the observation that there is an increased incidence of TMD in inexperienced divers. The study was held between 2006 and 2011. Ninety-seven divers were referred with the complaint of pain around temporomandibular area. The divers were classified according to their diving experience. Symptoms and signs of TMD were graded. Fourteen divers were diagnosed with TMD. Temporomandibular disorder was seen more frequently in inexperienced divers than in experienced divers (P = 0.0434). The most prevalent symptom was an increased effort for mouthpiece gripping. Temporomandibular joint tenderness and trigger point activation were the mostly seen physical signs. Thirteen divers had an improvement with therapy. The increased effort for stabilizing the mouthpiece is a recognized factor in TMD development. Attention must be paid to an association of scuba diving with TMDs, especially in inexperienced divers having a scuba certification training.Bir dalış regülatöründe ağızlık dizaynının SCUBA dalıcılarında temporomandibuler bozukluk (TMB) riskini arttırdığı bilinmektedir. Dalış regülatörünün tüm ağırlığı artiküler ve periartiküler problemlere sebeb olacak şekilde temporomandibuler eklem (TME) üzerine yansımaktadır. Çalışmamızda, dalış sertifikası eğitimi alan SCUBA dalıcılarında TMB prevelansını araştırdık. Aynı zamanda, TMB’ye yol açan faktörleri belirlemek ve dalış eğitimine bağlı anksiyetenin belirginleştiği tecrübesiz dalıcılarda TMB’nin daha sık görüldüğüne dair gözlemi aydınlatmayı amaçladık. Gereç ve yöntem: Çalışmamız, 2006 ve 2011 arasındaki 5,5 yıllık bir süre içinde gerçekleştirildi. 97 dalıcı temporomandibuler alan etrafında belirginleşen ağrı şikayeti ile refere edildiler. Dalıcılar tecrübe seviyelerine göre sınıflandırıldılar. TMB’ye ait belirti ve bulgular belirlendi ve sınıflandırıldı. Bulgular: 14 dalıcıda TMB teşhis edildi. TMB’nun tecrübesiz dalıcılarda tecrübelilerden daha sık görüldüğü saptandı (p=0.0434). En sık görülen belirti dalışta ağızlığı tutma eforunun artması olarak saptandı. TME hassasiyeti ve tetik nokta aktivasyonu en sık görülen bulgular olarak saptandılar. 13 dalıcıda tedavi ile iyileşme sağlandı. Sonuç: Dalış regülatörünün ikinci kademesinin ağızlığını sabitleme eforu TMB gelişiminde bilinen bir faktördür. Dalış sertifikasyonu eğitiminde artan anksiyete TMB prevelansında artışa neden olmaktadır
A new 3D FEM formulation for the solution of potential fields in magnetic induction problems
Time-varying magnetic fields are applied to living tissues for different purposes in medicine. For all applications, the induced current distributions must be accurately estimated in order to obtain the desired medical results. In this study a new 3D finite element method (FEM) formulation is derived. A code is prepared to implement these formulations using 20 noded isoparametric cubic elements. The accuracy of solutions is tested for three simple geometries and series expansion method is used to derive analytical expressions whenever it is necessary. It is shown that, for the selected geometries error in FEM solutions are less than 1%, and can be improved by increasing the number of nodes. The new 3D FEM solver runs in a 166 MHz PC using 128 Mbyte memory and is capable of solving a problem with 100.000 nodes in 80 minutes
Türkiye düzenli ilerleme raporları’nın kapasite kavramı açısından incelenmesi
Uluslararası örgütler tarafından gündeme getirilen ve devletlerin yeniden yapılandırılmasında kullanılan kapasite kavramı, Avrupa
Birliği entegrasyon süreci açısından da oldukça önemlidir. Birliğin kapasite yaklaşımını referans belgelerinden, kapasite beklentilerini
ise ilerleme raporlarından izlemek mümkündür. Bu çalışmanın amacı, AB’nin kapasite kavramı hakkındaki kurumsal yaklaşımının
referans belgeleri üzerinden ortaya konulması ve Türkiye’ye yönelik ilerleme raporlarında kavramın, kullanım sıklığı, türleri, kullanım
şekli, fasıllar ve kurumlarla ilişkisi bakımından incelenmesidir. Çalışmada, ilerleme raporlarının analizi, nitel veri analizi yöntemine
olanak sağlayan MAXQDA11 yazılım programı aracılığıyla yapılmıştır. Araştırma sonucunda kapasite kavramının yoğun olarak
kullanıldığı, kullanım şekli bakımından olumsuz ifadelerin daha fazla olduğu, idari kapasitenin en sık tekrarlanan kapasite türü
olduğu, kavramın büyük bir kısmının fasıllarda geçtiği, bakanlıkların yanında yeni oluşturulan kurumların da doğrudan kapasite
kavramıyla ilişkilendirildiği tespit edilmiştir. Kapasite değerlendirmesi yapılırken çevresel faktörler ve aktörler ile bunlar arasındaki
ilişkilerin iyi analiz edilmesi gerekmektedir...
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