Regularization of energy-momentum tensor correlators and parity-odd terms

We discuss the problem of regularizing correlators in conformal field theories. The only way to do it in coordinate space is to interpret them as distributions. Unfortunately except for the simplest cases we do not have tabulated mathematical results. The way out we pursue here is to go to momentum space and use Feynman diagram techniques and their regularization methods. We focus on the energy-momentum tensor correlators and, to gain insight, we compute and regularize 2-point functions in 2d with various techniques both in coordinate space and in momentum space, obtaining the same results. Then we do the same for 2-point functions in 4d. Finally we turn to 3-point function in 4d, and concentrate on the parity-odd part. We derive in particular the regularized trace and divergence of the energy-momentum tensor in a chiral fermion model. We discuss the problems related to the parity-odd trace anomaly.Comment: 40 pages, 1 figure. v2: minor changes and typos correcte

Duality in Supergravity Theories

We present a unified treatment in superspace of the two dual formulations of $D=10$, $N=1$ {\it pure} supergravity based on a strictly super-geometrical framework: the only fundamental objects are the super Riemann curvature and torsion, and the related Bianchi identities are sufficient to set the theory on shell; there is no need to introduce, from the beginning, closed three- or seven-superforms. This formulation extends also to {\it non minimal} models. Moreover, in this framework the algebraic analogy between pure super Yang--Mills theories and pure supergravity in $D=10$ is manifest. As an additional outcome in the present formulation the supersymmetric partner of the ABBJ-Lorentz anomaly in pure $D=10$ supergravity can be computed in complete analogy to the ABBJ-gauge anomaly in supersymmetric Yang--Mills theories in ten dimensions. In the same framework we attack the issue of duality in $N=1$, $D=11$ supergravity showing in detail that duality holds at the kinematical level in superspace while it is broken by the dynamics. We discuss also possible extensions of this theory which could be related to quantum corrections of the eleven dimensional membrane.Comment: 30 pages of tex, DFPD/93/TH/51 - (to appear in Nucl. Phys. B

The supersymmetric version of the Green--Schwarz anomaly cancellation mechanism

The $N=1$, $D=10$ Supergravity--Super--Yang--Mills (SUGRA-SYM) theory is plagued by ABBJ gauge and Lorentz anomalies which are cancelled via the Green-Schwarz anomaly cancellation mechanism. Due to the fact that the ABBJ anomalies are not invariant under supersymmetry (SUSY) transformations one concludes that the theory is plagued also by a SUSY anomaly. For the gauge groups $SO(32)$ and $E_8\times E_8$ we compute this SUSY anomaly, by solving a coupled cohomology problem, and we show that it can be cancelled by subtracting from the action the known Green--Schwarz counterterm, the same which cancels also the ABBJ anomaly, the expected result. Finally, we argue that the corresponding mechanism does not apply in the dual SUGRA-SYM, related to the heterotic five-brane.Comment: DFPD/94/TH/01, 11 pages, one reference correcte

ductile fracture assessment of x65 steel using damage mechanics

Abstract: Strain-based design for offshore pipeline requires a considerable experimental work aimed to determine the material fracture toughness and the effective strain capacity of pipe and welds. Continuum damage mechanics can be used to limit the experimental effort and to perform most of the assessment analysis and evaluation at simulation level. In this work, the possibility to predict accurately ductile rupture in X65 class steel for offshore application, using a CDM model, is shown. The procedure for material and damage model parameters identification is presented and applied to X65, customer grade steel. Then, damage model predictive capabilities have been validated predicting ductile crack growth in SENB and SENT fracture specimen

Changes in emergency psychiatric consultations in time of COVID-19: a retrospective observational study in the Verona Academic Hospital over the two pandemic years 2020-2021

Background: During the first months of the COVID-19 pandemic, local health authorities in most Italian regions prescribed a reduction of ordinary outpatient and community mental health care. The aim of this study was to assess the impact of the COVID-19 pandemic on access to the emergency departments (ED) for psychiatric consultation in the pandemic years 2020 and 2021 compared to 2019. Methods: This is a retrospective study conducted by using routinely collected administrative data of the two EDs of the Verona Academic Hospital Trust (Verona, Italy). All ED psychiatry consultations registered from 01.01.2020 to 31.12.2021 were compared with those registered in the pre-pandemic year (01.01.2019 to 31.12.2019). The association between each recorded characteristic and the year considered was estimated by chi-square or Fisher's exact test. Results: A significant reduction was observed between 2020 and 2019 (-23.3%) and between 2021 and 2019 (-16.3%). This reduction was most evident in the lockdown period of 2020 (-40.3%) and in the phase corresponding to the second and third pandemic waves (-36.1%). In 2021, young adults and people with diagnosis of psychosis showed an increase in requests for psychiatric consultation. Conclusions: Fear of contagion may have been an important factor in the overall reduction in psychiatric consultations. However, psychiatric consultations for people with psychosis and for young adults increased. This finding underlines the need for mental health services to implement alternative outreach strategies aimed to support, in times of crisis, these vulnerable segments of the population

Elevated urinary levels of urokinase-type plasminogen activator receptor (uPAR) in pancreatic ductal adenocarcinoma identify a clinically high-risk group

BACKGROUND: The urokinase plasminogen activator receptor is highly expressed and its gene is amplified in about 50% of pancreatic ductal adenocarcinomas; this last feature is associated with worse prognosis. It is unknown whether the level of its soluble form (suPAR) in urine may be a diagnostic-prognostic marker in these patients. METHODS: The urinary level of suPAR was measured in 146 patients, 94 pancreatic ductal adenocarcinoma and 52 chronic pancreatitis. Urine from 104 healthy subjects with similar age and gender distribution served as controls. suPAR levels were normalized with creatinine levels (suPAR/creatinine, ng/mg) to remove urine dilution effect. RESULTS: Urinary suPAR/creatinine values of pancreatic ductal adenocarcinoma patients were significantly higher (median 9.8; 25(th)-75(th )percentiles 5.3-20.7) than those of either healthy donors (median 0; 0-0.5) or chronic pancreatitis patients (median 2.7; 0.9-4.7). The distribution of values among cancer patients was widespread and asymmetric, 53% subjects having values beyond the 95(th )percentile of healthy donors. The values of suPAR/creatinine did not correlate with tumour stage, Ca19-9 or CEA levels. Higher values correlated with poor prognosis among non-resected patients at univariate analysis; multivariate Cox regression identified high urinary suPAR/creatinine as an independent predictor of poor survival among all cancer patients (odds ratio 2.10, p = 0.0023), together with tumour stage (stage III odds ratio 2.65, p = 0.0017; stage IV odds ratio 4.61, p < 0.0001) and female gender (odds ratio 1.85, p = 0.01). CONCLUSIONS: A high urinary suPAR/creatinine ratio represents a useful marker for the identification of a subset of patients with poorer outcome