Temperature Dependence of the QCD Coupling

We present a one-loop calculation of a gauge invariant QCD beta function. Using both momentum and temperature renormalization group equations we investigate the running coupling in the magnetic sector as a function of temperature and momentum scale. At fixed momentum scale we find that, in contrast to $\lambda\phi^4$ or QED, high-temperature QCD is strongly coupled, even after renormalization group improvement. However, if the momentum scale is changed simultaneously with temperature in a specified manner, the coupling decreases. We also point out in what regime dimensional reduction occurs. Both the cases $N_f$ smaller and larger than $\frac{11}{2} N_c$ are discussed.Comment: 10 pages, LaTeX (5 postscript figures available), ITFA-93-11,THU-93/0

Critical Temperature and Amplitude Ratios from a Finite-Temperature Renormalization Group

We study \l\f^4 theory using an environmentally friendly finite-temperature renormalization group. We derive flow equations, using a fiducial temperature as flow parameter, develop them perturbatively in an expansion free from ultraviolet and infrared divergences, then integrate them numerically from zero to temperatures above the critical temperature. The critical temperature, at which the mass vanishes, is obtained by integrating the flow equations and is determined as a function of the zero-temperature mass and coupling. We calculate the field expectation value and minimum of the effective potential as functions of temperature and derive some universal amplitude ratios which connect the broken and symmetric phases of the theory. The latter are found to be in good agreement with those of the three-dimensional Ising model obtained from high- and low-temperature series expansions.Comment: 14 pages of LaTeX. Postscript figures available upon request form [email protected]

The Finite-Temperature Renormalization Group Applied to λϕ⁴ Theory and QCD

In this paper we apply the finite-temperature renormalization group from the point of view of “environmentally friendly” renormalization. We study both λϕ⁴ theory and the magnetic sector of QCD. At one loop level the complete temperature range of λϕ⁴ is successfully described in terms of the parameters of the zero temperature theory. We show also how the critical temperature can be calculated in terms of the latter. For the magnetic sector of QCD, in distinction to λϕ⁴, a one-loop finite temperature renormalization group improvement is not sufficient to describe the high-temperature regime

From soft harmonic phonons to fast relaxational dynamics in CH3_{3}NH3_{3}PbBr3_{3}

The lead-halide perovskites, including CH$_{3}$NH$_{3}$PbBr$_{3}$, are components in cost effective, highly efficient photovoltaics, where the interactions of the molecular cations with the inorganic framework are suggested to influence the electronic and ferroelectric properties. CH$_{3}$NH$_{3}$PbBr$_{3}$ undergoes a series of structural transitions associated with orientational order of the CH$_{3}$NH$_{3}$ (MA) molecular cation and tilting of the PbBr$_{3}$ host framework. We apply high-resolution neutron scattering to study the soft harmonic phonons associated with these transitions, and find a strong coupling between the PbBr$_{3}$ framework and the quasistatic CH$_{3}$NH$_{3}$ dynamics at low energy transfers. At higher energy transfers, we observe a PbBr$_{6}$ octahedra soft mode driving a transition at 150 K from bound molecular excitations at low temperatures to relatively fast relaxational excitations that extend up to $\sim$ 50-100 meV. We suggest that these temporally overdamped dynamics enables possible indirect band gap processes in these materials that are related to the enhanced photovoltaic properties.Comment: (main text - 5 pages, 4 figures; supplementary information - 3 pages, 3 figures

Introducing a Calculus of Effects and Handlers for Natural Language Semantics

In compositional model-theoretic semantics, researchers assemble truth-conditions or other kinds of denotations using the lambda calculus. It was previously observed that the lambda terms and/or the denotations studied tend to follow the same pattern: they are instances of a monad. In this paper, we present an extension of the simply-typed lambda calculus that exploits this uniformity using the recently discovered technique of effect handlers. We prove that our calculus exhibits some of the key formal properties of the lambda calculus and we use it to construct a modular semantics for a small fragment that involves multiple distinct semantic phenomena

Overexpression of the adhesion signaling pathway is linked to short-term survival in pancreatic ductal adenocarcinoma

Background and objective: Pancreatic ductal adenocarcinoma (PDAC) is known for its unfavorable prognosis. Gaining insights into the molecular mechanisms that contribute to its progression is crucial for developing effective therapies. In this study, our objective was to investigate the molecular pathways associated with short-term survival in patients with PDAC. Methods: Immune profiles were analyzed from both long-term survivors (n = 10) and short-term survivors (n = 10) after surgical resection. Pathway scores were calculated to compare the two groups. Results: The “Adhesion” pathway emerged as the most significant pathway, exhibiting a notably higher score in the samples of short-term survivors (P &lt; 0.009). Within this pathway, significant findings were observed in genes related to integrins and CEACAM. Conclusion: The role of integrins in the tumor microenvironment of pancreatic cancer is of utmost importance, as they are found to be overexpressed in short-term survivors. These findings provide valuable insights into the underlying biology of PDAC and have potential implications for the development of therapeutic strategies.</p

Exocrine and endocrine pancreatic function in patients with pancreatico-jejunostomy or pancreatic duct occlusion after pancreaticoduodenectomy

Pancreatic duct occlusion (PDO) is performed in some centres to avoid complications of pancreaticojejunostomy (PJ) after pancreaticodudodenectomy. The aim of our study was to study the exo- and endocrine pancreatic function, nutritional status and quality of life in patients with a PJ or PDO after a pancreatico-duodenectomy (PD)