480 research outputs found
Minimal subtraction and the Callan-Symanzik equation
The usual proof of renormalizability using the Callan-Symanzik equation makes
explicit use of normalization conditions. It is shown that demanding that the
renormalization group functions take the form required for minimal subtraction
allows one to prove renormalizability using the Callan-Symanzik equation,
without imposing normalization conditions. Scalar field theory and quantum
electrodynamics are treated.Comment: 6 pages, plain Te
Abelian 3-form gauge theory: superfield approach
We discuss a D-dimensional Abelian 3-form gauge theory within the framework
of Bonora-Tonin's superfield formalism and derive the off-shell nilpotent and
absolutely anticommuting Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST
symmetry transformations for this theory. To pay our homage to Victor I.
Ogievetsky (1928-1996), who was one of the inventors of Abelian 2-form
(antisymmetric tensor) gauge field, we go a step further and discuss the above
D-dimensional Abelian 3-form gauge theory within the framework of BRST
formalism and establish that the existence of the (anti-)BRST invariant
Curci-Ferrari (CF) type of restrictions is the hallmark of any arbitrary p-form
gauge theory (discussed within the framework of BRST formalism).Comment: LaTeX file, 8 pages, Talk delivered at BLTP, JINR, Dubna, Moscow
Region, Russi
Implications of interleukin-6 (Il-6)-blockade for severe covid-19 infection in patients with multiple myeloma
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Gluon Fragmentation into Heavy Quarkonium
The dominant production mechanism for heavy quark-antiquark bound states in
very high energy processes is fragmentation, the splitting of a high energy
parton into a quarkonium state and other partons. We show that the
fragmentation functions describing these processes can be calculated
using perturbative QCD. We calculate the fragmentation functions for a gluon to
split into S-wave quarkonium states to leading order in the QCD coupling
constant. The leading logarithms of , where is the factorization
scale and is the heavy quark mass, are summed up using Altarelli-Parisi
evolution equations.Comment: LateX 11 pages (3 figures available upon request). NUHEP-TH-92-2
Two loop effective potential for < A^2_\mu > in the Landau gauge in quantum chromodynamics
We construct the effective potential for the dimension two composite operator
1/2 A^{a 2}_\mu in QCD with massless quarks in the Landau gauge for an
arbitrary colour group at two loops. For SU(3) we show that an estimate for the
effective gluon mass decreases as N_f increases.Comment: 17 latex page
Predictive Values of Transcutaneous Oxygen Tension for Above-the-ankle Amputation in Diabetic Patients with Critical Limb Ischemia
ObjectiveTo assess the values of transcutaneous oxygen tension (TcPO2) capable of predicting above-the-ankle amputation in diabetic patients diagnosed for critical limb ischemia (CLI) according to the criteria of the TransAtlantic Inter-Society Consensus.DesignRetrospective study.MethodsFrom January 1999 to December 2003, 564 diabetic patients were consecutively hospitalized for CLI in one limb. Revascularization with angioplasty or bypass graft was performed when possible and, if not possible, prostanoid therapy was used. In patients in whom therapies did not relieve the rest pain or the gangrene was extended above the Chopart joint, an above-the-ankle-amputation was performed. After treatment TcPO2 values were evaluated in all patients at the dorsum of the foot.ResultsFifty-five (9.8%) patients underwent an above-the-ankle amputation: 22 of 420 patients who underwent angioplasty, 17 of 117 patients who underwent bypass (14.5%) and 16 of 27 patients in whom revascularization was not possible. Post-treatment TcPO2, measured by a receiver operating characteristic (ROC) curve, showed a value 34mmHg as the best threshold for determining the need for revascularization, with an area under the curve of 0.89 (95%CI 0.85–0.94).Using logistic regression analysis the probability of above-the-ankle amputation for this threshold is 9.7% and reduces to 3% for TcPO2>40mmHg.ConclusionTcPO2 levels<34mmHg indicate the need for revascularization, while for values ≥ 34<40mmHg this need appears less pressing, although there remains a considerable probability of amputation. TcPO2 levels greater than 40mmHg suggest that revascularization is dependent on the severity of tissue loss and possible morbidity caused by the procedure
Pré-compostagem de cadáveres de bovinos acometidos pelo botulismo.
Foram prĂ©-compostados, em cĂ©lulas individuais e isoladas, cinco cadáveres de bovinos acometidos pelo botulismo com a finalidade de monitorar a presença de esporos de Clostridium botulinum e de toxina botulĂnica antes e apĂłs o processo de decomposição em leira estática com fonte de carbono. O diagnĂłstico da intoxicação nos animais foi baseado nas caracterĂsticas clĂnico-patolĂłgicas, epidemiolĂłgicas ou laboratoriais. Dos cinco bovinos com evolução clĂnica crĂ´nica de botulismo, cujos cadáveres foram prĂ©-compostados, trĂŞs foram acometidos pela toxina tipo D, um pelo complexo CD e um dos animais foi negativo na tentativa de detecção da toxina e de esporos da bactĂ©ria nas vĂsceras pelo bioensaio e neutralização em camundongo. O processo de prĂ©-compostagem foi realizado em leira estática, com o uso de material carbonáceo umidificado como substrato e esquartejamento do animal, vedado individualmente com lona plástica e sem aeração por um perĂodo de 50 dias. A temperatura das leiras foi monitorada durante o perĂodo e oscilou de 40,5-52,4ÂşC. ApĂłs a abertura das leiras, pĂ´de-se constatar a completa decomposição de todo material mole, com redução significativa do seu peso (de 26,5-44,5%), restando apenas os ossos. NĂŁo foi detectado esporo ou toxina botulĂnica no interior dos ossos (n=5 para cada cadáver). Nas 200 amostras examinadas do homogeneizado restante (n=40 para cada cadáver), em apenas duas amostras de uma leira foram detectados esporos de C. botulinum tipo C, enquanto que todas foram negativas para a tentativa de detecção da toxina botulĂnica pelo bioensaio em camundongo. Da forma como foi avaliado o processo de prĂ©-compostagem de bovinos mortos pela intoxicação botulĂnica nĂŁo contribuiu para a proliferação de C. botulinum. Five carcasses of cattle that died from botulism were composted in individual isolated beds with the purpose of monitoring the effect on spores of Clostridium botulinum and of botulinum toxin. The diagnosis of botulinum poisoning was based on clinical and pathological, epidemic and/or laboratorial characteristics. Of the five bovines with clinical signs of chronic botulism, three were affected by the type D toxin, one by the CD complex, and one was negative for toxin and spores of C. botulinum in the viscera using a mouse bioassay. The composting process was carried out in beds with carcasses cut up and mixed with sawdust as a carbon source. They were kept anaerobic under a plastic sheet for 50 days. The temperature of the beds was monitored during the period and oscillated from 40.5 to 52.4ÂşC. After this time, soft tissue had complete decomposed with a significant loss of weight (26.5-44.5%). The remaining bones no longer contained spores or botulinum toxin in the 5 samples taken from each carcass. Only 2 of the 200 samples of homogenized remaining (40 for each carcass) contained spores of C. botulinum type C. All samples were negative for botulinum toxin using the mouse bioassay. Composting carcasses of cattle that died from botulism eliminated botulinum spores and toxin from the remains
Interacting Vector-Spinor and Nilpotent Supersymmetry
We formulate an interacting theory of a vector-spinor field that gauges
anticommuting spinor charges \{Q_\alpha{}^I, Q_\beta{}^J \} = 0 in arbitrary
space-time dimensions. The field content of the system is (\psi_\mu{}^{\alpha
I}, \chi^{\alpha I J}, A_\mu{}^I), where \psi_\mu{}^{\alpha I} is a
vector-spinor in the adjoint representation of an arbitrary gauge group, and
A_\mu{}^I is its gauge field, while \chi^{\alpha I J} is an extra spinor with
antisymmetric adjoint indices I J. Amazingly, the consistency of the
vector-spinor field equation is maintained, despite its non-trivial
interactions.Comment: 10 pages, no figure
Zur Personenwahrnehmung im Attributionsgeschehen: Eine Replikation der klassischen Arbeit von Heider und Simmel (1944)
Als zentraler Befund der einflussreichen Arbeit von Heider und Simmel [American Journal of Psychology, 57, 243-259 (1944)]zeigte sich, dass bewegte geometrische Objekte ganz überwiegend als intentional handelnde Lebewesen wahrgenommen werden und diese wiederum mehrheitlich als Personen. Da die Originaluntersuchung ausschließlich Frauen miteinbezog und die Darstellung der Ergebnisse mitunter keine genauen Angaben zur Häufigkeit personaler Kausalität erlaubt, wird eine Replikation durchgeführt, um die Befunde auf eine breiter generalisierbare Basis zu stellen. Unter Verwendung des Originalversuchsmaterials zeigt sich auch bei konservativer Analyse der Ergebnisse, dass geschlechtsunabhängig weniger als 35 % der Teilnehmenden die geometrischen Objekte als Lebewesen beschrieben. Von denjenigen, die die Objekte als beseelt wahrnahmen, wurden diese in etwa 80 % der Fälle als Menschen bezeichnet. Mögliche Erklärungen dieser Abweichungen von den Originalbefunden werden diskutiert
Quantum properties of a non-Abelian gauge invariant action with a mass parameter
We continue the study of a local, gauge invariant Yang-Mills action
containing a mass parameter, which we constructed in a previous paper starting
from the nonlocal gauge invariant mass dimension two operator F_{\mu\nu}
(D^2)^{-1} F_{\mu\nu}. We return briefly to the renormalizability of the model,
which can be proven to all orders of perturbation theory by embedding it in a
more general model with a larger symmetry content. We point out the existence
of a nilpotent BRST symmetry. Although our action contains extra
(anti)commuting tensor fields and coupling constants, we prove that our model
in the limit of vanishing mass is equivalent with ordinary massless Yang-Mills
theories. The full theory is renormalized explicitly at two loops in the MSbar
scheme and all the renormalization group functions are presented. We end with
some comments on the potential relevance of this gauge model for the issue of a
dynamical gluon mass generation.Comment: 17 pages. v2: version accepted for publication in Phys.Rev.
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