Compact Lattice QED and the Coulomb Potential

The potential energy of a static charge distribution on a lattice is rigorously computed in the standard compact quantum electrodynamic model. The method used follows closely that of Weyl for ordinary quantum electrodynamics in continuous space-time. The potential energy of the static charge distribution is independent of temperature and can be calculated from the lattice version of Poisson's equation. It is the usual Coulomb potential.Comment: 6 pages, includes one figure in Topdrawer, NUB 3054/9

Consistent irrelevant deformations of interacting conformal field theories

I show that under certain conditions it is possible to define consistent irrelevant deformations of interacting conformal field theories. The deformations are finite or have a unique running scale ("quasi-finite"). They are made of an infinite number of lagrangian terms and a finite number of independent parameters that renormalize coherently. The coefficients of the irrelevant terms are determined imposing that the beta functions of the dimensionless combinations of couplings vanish ("quasi-finiteness equations"). The expansion in powers of the energy is meaningful for energies much smaller than an effective Planck mass. Multiple deformations can be considered also. I study the general conditions to have non-trivial solutions. As an example, I construct the Pauli deformation of the IR fixed point of massless non-Abelian Yang-Mills theory with N_c colors and N_f <~ 11N_c/2 flavors and compute the couplings of the term F^3 and the four-fermion vertices. Another interesting application is the construction of finite chiral irrelevant deformations of N=2 and N=4 superconformal field theories. The results of this paper suggest that power-counting non-renormalizable theories might play a role in the description of fundamental physics.Comment: 23 pages, 5 figures; reference updated - JHE

Novel fast semi-automated software to segment cartilage for knee MR acquisitions

AbstractObjectiveValidation of a new fast software technique to segment the cartilage on knee magnetic resonance (MR) acquisitions. Large studies of knee osteoarthritis (OA) will require fast and reproducible methods to quantify cartilage changes for knee MR data. In this report we document and measure the reproducibility and reader time of a software-based technique to quantify the volume and thickness of articular cartilage on knee MR images.MethodsThe software was tested on a set of duplicate sagittal three-dimensional (3D) dual echo steady state (DESS) acquisitions from 15 (8 OA, 7 normal) subjects. The repositioning, inter-reader, and intra-reader reproducibility of the cartilage volume (VC) and thickness (ThC) were measured independently as well as the reader time for each cartilage plate. The root-mean square coefficient of variation (RMSCoV) was used as metric to quantify the reproducibility of VC and mean ThC.ResultsThe repositioning RMSCoV was as follows: VC=2.0% and ThC=1.2% (femur), VC=2.9% and ThC=1.6% (medial tibial plateau), VC=5.5% and ThC=2.4% (lateral tibial plateau), and VC=4.6% and ThC=2.3% (patella). RMSCoV values were higher for the inter-reader reproducibility (VC: 2.5–8.6%) (ThC: 1.9–5.2%) and lower for the intra-reader reproducibility (VC: 1.6–2.5%) (ThC: 1.2–1.9%). The method required an average of 75.4min per knee.ConclusionsWe have documented a fast reproducible semi-automated software method to segment articular cartilage on knee MR acquisitions

Hall-conductivity sign change and fluctuations in amorphous Nbx_{x}Ge1−x_{1-x} films

The sign change in the Hall conductivity has been studied in thin amorphous Nb$_{1-x}$Ge$_x (x\approx$0.3) films. By changing the film thickness it is shown that the field at which the sign reversal occurs shifts to lower values (from above to below the mean-field transition field $H_{c2}$) with increasing film thickness. This effect can be understood in terms of a competition between a positive normal and a negative fluctuation contribution to the Hall conductivity.Comment: 5 pages, 4 figures, to appear in Phys. Rev.

Geochronology, Petrology and Geochemistry of Intermediate and Mafic Rocks of Bornaward Plutonic Complex (Northwest Bardaskan, Iran)

The study area is located in the northeast of Iran (the Khorasan Razavi province) and 28 km northwest of Bardaskan city and in position of 57˚ 46΄ to 57˚ 52΄ latitude and 35˚ 21΄ to 35˚ 24΄ longitude. The study area is a part of Taknar zone. The Taknar geological-structural zone is situated in the north Central Iranian microcontinental and it is a part of Lut block (Fig.1). Taknar plutonic complex that is situated in the Taknar structural zone is located in the northern part of Iranian microcontinent. Chemical analysis of REE and minor elements of samples of the Bornaward diorites and gabbro’s took place in the ACME Lab. in Vancouver, Canada, by the ICP-MS method (Table. 1). For the Bornaward diorite dating by the U-Pb method, zircon grains of material remaining in the sieve, Bromoform were isolated from light minerals by cleaning and were isolated with a minimum size of 25 microns, and then studies took place in the Crohn's Laser Lab Arizona (Gehrels et al., 2008). Measurement of Rb, Sr, Sm and Nd isotopes and (143Nd/144Nd)i , (87Sr/86Sr)i ratios and ƐNd (T=552), ƐNd (T=0), ƐSr (T=552) and ƐSr (T=0) took place in radioisotope Laboratory, University of Aveiro in Portugal. Geology of study area The study area forms the central part of the Bornaward plutonic complex. This complex is a granitoid assemblage including granite, granodiorite, tonalite and granophyre. The central part has been formed by intermediate and basic intrusive rocks such as diorite, quartz diorite and gabbro units (Fig. 2). From the genetic point of view, the intermediate and mafic rocks of the Taknar plutonic complex does not have any relationship with granitoid rocks of this assemblage, and they are related to a similar magmatic phase but are separated from this granitoid assemblage. However, these mafic and intermediate units are older than granitic units at the rim of the complex that are called Bornaward granite. The main minerals in the diorite and quartz diorite rocks are plagioclase and hornblende and we can see biotite in the quartz dioritic rocks. Quartz exists as tiny grains and anhedral and in the matrix rock. The amount of Quartz in the quartz diorites is 5 to 20%. Plagioclases usually have normal zoning and are highly altered to sericite. Most of the plagioclases were saussuritized. Altered minerals resulted from plagioclase and hornblende are sericite, epidote, chlorite, zoisite and clinozoisite.The main minerals in the gabbro are pyroxene, hornblende, and fine grains plagioclase. Minor minerals in the rocks are apatite, magnetite and other opaque. The main texture of intermediate and mafic rocks in this assemblage is medium granular to coarse grain and especially in the intermediate rocks and gabbro rocks, we can see scattered poikilitic, intersertal, sub-ophitic and porphyroid texture. The area diorite and gabbro is located locate in Tholeiitic and Calc-alkaline series (Fig. 9). Shand index (Al2O3/(CaO+Na2O+K2O)) is obtained under 1.1, in Metaluminous field (Fig. 7) and I-type granite field (Chappell and White, 2001). Based on the TAS diagram (Middlemost, 1985), all the diorite and gabbro samples are located in diorite, gabbro-diorite and gabbro-norite groups (Fig. 6). The diorite and gabbro show enrichment LREE and low ascending pattern ((La/Yb)N =1.40-6.12 and LaN =12.26-75.81). Measurement of U-Th-Pb isotopes of the Bornaward diorite zircons of BKCh-03 sample (Table 2) show that its age is related to 551.96±4.32 Ma ago (Upper Precambrian (Neoproterozoic) (Ediacaran). The (87Sr/86Sr)i and (143Nd/144Nd)i content of Bornaward diorite and gabbro rocks is located in the range of 0.7038 to 0.7135 and 0.51203 to 0.51214, respectively (Tables 3 and 4). It shows that the diorite and gabbro rocks can be affected by hydrothermal alteration because their (87Sr/86Sr)i is above (Fig. 16). The numeral amounts of ƐNd(T=552) of Bornaward diorite and gabbro are 2.0 to 4.0. The Bornaward diorite and gabbro rocks show a widespread enriched pattern of Rb, U, K, Pb, La and Th elements than chondrite, while Ba, Ti, Ta, Sr and Nb elements show reduction as a result of fractional crystallization (Fig. 11). The rocks of this complex are formed at the continental margin and VAG environment (Fig. 18) which is related to the subduction of the oceanic crust that exists between the Iranian microcontinent and the Afghan Block. This assemblage with age of Late Neoproterozoic is the result of extensive magmatism in the northern part of the Iranian microcontinent due to Katangahi orogeny event. The similar magmatism in the northern part of the Iranian microcontinent is existing as Khaf-Kashmar-Bardeskan volcanoplutonic belt. Based on the geochemical investigations, the magmatism of these rocks has been tholeiitic and calk-alkaline and have formed the coexistent rocks with I-type granites. Alumina saturation index for intermediate and mafic rocks of Bornaward complex is metalumina. These are medium-K rocks and enriched in the LILE such as Rb, Pb, U and Th while depleted of the Nb, Ti, Ta, Sr and Ba. Therefore, it shows that these rocks have resulted from the mixing by the lower crust. The low (87Sr/86Sr)i Bornaward diorite and gabbro rocks and the numeral amounts of Ɛ0Nd(present) of these rocks from -0.2 to 4.0 show that production of such intrusive masses can be attributed to the source of upper mantle or contaminated lower continental crust. Environment of formation of the intermediate and basic rocks of the Bornaward plutonic complex is active continental margin and volcanic arc environment.کمپلکس پلوتونیک برنورد واقع در زون ساختاري تکنار، در شمال خرد قاره ایران مرکزي و د ر 20 کیلومتري شما لغر ب شهرستان بردسکن قرار دارد. این مجموعه با سنی معادل اواخر پرکامبرین (نئوپروتروزوئیک)، نتیجه فعالیت ماگمایی وس یع شمال خرد قاره ایران مرکزي در اثر پدیده کوهزایی کاتانگاهی است. مشابه این ماگماتیسم در شمال خرد قاره ایران مرکزي بهصورت کمربند ولکانو- پلوتونیک خواف- کاشمر- بردسکن همچون گرانیتوئیدهاي کاشمر وجود دارد. این کمپلکس بزرگمقیاس در واقع مجموع هاي گرانیتوئید ي شامل سنگهاي گرانیت ی، گرانودیوری تی، تونالی تی و گرانوفی ري است که بخ ش مرکزي آن از ی ک گرو ه واحدهاي گابرویی، دیوریت ی و کوارتزدیوریتی تشکیلشده است. بافت اصلی این سن گهاي حدواسط و مافی ک، گرانولار متوسط تا درش تبلور اس ت و باف تهاي پورفیروئید بهویژه در سنگهاي حدواسط و بافتهاي پوئیکلیتیک و سابافیتیک در سن گهاي گابرویی ب هصورت پراکنده به چشم میخورد. کانی اصلی فرومنیزیندار سنگهاي مافیک و حدواسط، کانی هورنبلند است و در نمونههاي کوارتزدیوریتی، بیوتیت نیز دیده میشود. سنگهاي حدواسط و مافیک کمپلکس پلوتونیک برنورد از لحاظ ژنتیکی با سنگهاي گرانیتوئیدي این مجموعه ارتباطی مستقیم دارند. از لحاظ ارتباط صحرایی و بررسیهاي سنی چنین مشخص میشود که این واحدهاي مافیک و حدواسط نسبت به واحد گرانیتی و دیگر واحدهاي نفوذي اسیدي این کمپلکس قدیمیتر بوده و توسط این واحدها قطع شدهاند. 551 میلی ون /96 ±4/ سن این توده هاي نفوذي 32 ،U-Pb بر اساس سنسنجی دیوریتهاي منطقه برنورد با استفاده از کانی زیرکن بهروش سال قبل (اواخر پرکامبرین) بهدست آمده اس ت. بر پایه بررس یها ي ژئوشیمیایی، تحولات ماگمایی این سن گها از نوع تولئیتی و کالکآلکالن بوده و شاخص اشباع از آلومین این سنگها متاآلومین است. دیوریتها و گابروهاي برنورد از نوع پتاسیم متوسط بوده و از غنیشدگی نشان میدهند؛ در حالیکه عناصري Th بههمراه La, Rb, K, U, Pb لحاظ ویژگیهاي ژئوشیمیایی نسبت به عناصر ناسازگار تهیشدگی شاخصی را در مقایسه با کندریت ارائه میدهند. Nb, Ti, Ta, Sr, Ba مانند 0 بهدست آمده است. مقدار عددي نسبت / 0 تا 51214 / 143 ) دیوریتها و گابروهاي برنورد در گستره 51203 Nd/144Nd)i Sr)i 86 Sr/ 87 دیوریتها و گابروهاي ƐNd(T= 0 اندازهگیري شده است. مقدار عددي ( 552 / 0 تا 7135 / ) این تودههاي نفوذي در گستره 7038 Ɛ0Nd(present) 87 ) نمونههاي دیوریت و گابروهاي منطقه برنورد و مقادیر Sr/86Sr)i 4 بهدست آمده است. مقادیر پایین / 2 تا 0 / برنورد از 0 4 محاسبهشده است، نشاندهنده آن است که تولید چنین تودههاي نفوذي م یتواند به منبعی از گوشته / 0- تا 0 / این تودههاي نفوذي که 2 بالایی یا پوسته قارهاي زیرین تحت آلایش قرارگرفته شده، نسبتداده شود. محیط تشکیل این دسته از سن گهاي کمپلک س پلوتونیک برنورد، حاشیه فعال قاره و محیط کمان آتشفشانی 1 است که میتواند به فرورانش پوسته اقیانوسی موجود ب ین خرد قاره ایران مرکزي و بلوك افغان مرتبط باشد. واژههاي کلیدي: کمپلکس، سنسنجی، خرد قاره، ماگماتیسم، پرکامبرین، بردسکن، تکناpublishe

From early markers to neuro-developmental mechanisms of autism

A fast growing field, the study of infants at risk because of having an older sibling with autism (i.e. infant sibs) aims to identify the earliest signs of this disorder, which would allow for earlier diagnosis and intervention. More importantly, we argue, these studies offer the opportunity to validate existing neuro-developmental models of autism against experimental evidence. Although autism is mainly seen as a disorder of social interaction and communication, emerging early markers do not exclusively reflect impairments of the “social brain”. Evidence for atypical development of sensory and attentional systems highlight the need to move away from localized deficits to models suggesting brain-wide involvement in autism pathology. We discuss the implications infant sibs findings have for future work into the biology of autism and the development of interventions

Green function techniques in the treatment of quantum transport at the molecular scale

The theoretical investigation of charge (and spin) transport at nanometer length scales requires the use of advanced and powerful techniques able to deal with the dynamical properties of the relevant physical systems, to explicitly include out-of-equilibrium situations typical for electrical/heat transport as well as to take into account interaction effects in a systematic way. Equilibrium Green function techniques and their extension to non-equilibrium situations via the Keldysh formalism build one of the pillars of current state-of-the-art approaches to quantum transport which have been implemented in both model Hamiltonian formulations and first-principle methodologies. We offer a tutorial overview of the applications of Green functions to deal with some fundamental aspects of charge transport at the nanoscale, mainly focusing on applications to model Hamiltonian formulations.Comment: Tutorial review, LaTeX, 129 pages, 41 figures, 300 references, submitted to Springer series "Lecture Notes in Physics

Partial Wave Analysis of J/ψ→γ(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

BES data on $J/\psi \to \gamma (K^+K^-\pi^+\pi^-)$ are presented. The $K^*\bar K^*$ contribution peaks strongly near threshold. It is fitted with a broad $0^{-+}$ resonance with mass $M = 1800 \pm 100$ MeV, width $\Gamma = 500 \pm 200$ MeV. A broad $2^{++}$ resonance peaking at 2020 MeV is also required with width $\sim 500$ MeV. There is further evidence for a $2^{-+}$ component peaking at 2.55 GeV. The non-$K^*\bar K^*$ contribution is close to phase space; it peaks at 2.6 GeV and is very different from $K^{*}\bar{K^{*}}$.Comment: 15 pages, 6 figures, 1 table, Submitted to PL

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types