Vacuum Radiation and Symmetry Breaking in Conformally Invariant Quantum Field Theory

The underlying reasons for the difficulty of unitarily implementing the whole conformal group $SO(4,2)$ in a massless Quantum Field Theory (QFT) are investigated in this paper. Firstly, we demonstrate that the singular action of the subgroup of special conformal transformations (SCT), on the standard Minkowski space $M$, cannot be primarily associated with the vacuum radiation problems, the reason being more profound and related to the dynamical breakdown of part of the conformal symmetry (the SCT subgroup, to be more precise) when representations of null mass are selected inside the representations of the whole conformal group. Then we show how the vacuum of the massless QFT radiates under the action of SCT (usually interpreted as transitions to a uniformly accelerated frame) and we calculate exactly the spectrum of the outgoing particles, which proves to be a generalization of the Planckian one, this recovered as a given limit.Comment: 29 pages, Latex, 1 figure, to appear in Commun. Math. Phy

Conformal Spinning Quantum Particles in Complex Minkowski Space as Constrained Nonlinear Sigma Models in U(2,2) and Born's Reciprocity

We revise the use of 8-dimensional conformal, complex (Cartan) domains as a base for the construction of conformally invariant quantum (field) theory, either as phase or configuration spaces. We follow a gauge-invariant Lagrangian approach (of nonlinear sigma-model type) and use a generalized Dirac method for the quantization of constrained systems, which resembles in some aspects the standard approach to quantizing coadjoint orbits of a group G. Physical wave functions, Haar measures, orthonormal basis and reproducing (Bergman) kernels are explicitly calculated in and holomorphic picture in these Cartan domains for both scalar and spinning quantum particles. Similarities and differences with other results in the literature are also discussed and an extension of Schwinger's Master Theorem is commented in connection with closure relations. An adaptation of the Born's Reciprocity Principle (BRP) to the conformal relativity, the replacement of space-time by the 8-dimensional conformal domain at short distances and the existence of a maximal acceleration are also put forward.Comment: 33 pages, no figures, LaTe

Perioperative negative pressure pulmonary edema: case scenario: 2AP2‐11

Background: The Negative Pressure Pulmonary Edema (NPPE) is a multifactorial condition,reported in patients af ter general anesthesia. Despite being uncommon (0.05-0.1%),it is a potentially life-threatening emergency that can be fatal in 11-40%.It characteristically occurs af ter endotracheal intubation, but has already been described af ter Laringeal Mask Airway (LMA) use(1). As its occurrence is under-reported, our aim is to point out the importance of an expeditious diagnosis. Case report: 24-yr-old woman (50Kg, 1,60m), presented to the ambulatory surgery center for an a xillary ganglia excisional biopsy. Patient’s medical history was relevant only for a recurrent spontaneous pneumotorax. Unknown allergies.Normal pre-operative study. Inhalatory anesthesia,atraumatic LMA place.Anesthesia and surgical procedure were uneventful. Transferred to Postanesthesia Care Unit (PACU), spontaneously ventilating (SV). Ten minutes later, marked respiratory distress, tachypnea, cyanosis, accessory muscle utilization and significant arterial oxygen desaturation (40%)-treated by positive-pressure mask ventilation until improved peripheral oxygen saturation. Physical examination revealed bilateral dif fuse crackles and respiratory failure type I (PaO2 52mmHg). Chest radiograph with bilateral pulmonary infiltrates without pneumotorax signs. [Image 1] Transferred to Intermediate Care Unit,conscious, hemodynamically stable, SV with supplemental oxygen,SpO2>90%. An echocardiograph(normal) and an angio-computed tomography (acute pulmonary edema in resolution, no signs of thromboembolism) were performed. Progressive recovery without non-invasive pressure support, discharged from hospital on the 4th postoperative day. Follow-up in 8 weeks. Discussion: When considering dif ferential diagnosis of acute-onset perioperative pulmonary edema, NPPE was considered despite the absence of evident high airway obstruction. However, the clinical presentation and its rapid improvement are consistent with the diagnosis. Given the increasing use of LMA, similar episodes can become recurrent, being crucial its prompt recognitio

Salespeople performance evaluation with predictive analytics in B2B

Performance Evaluation is a process that occurs multiple times per year on a company. During this process, the manager and the salesperson evaluate how the salesperson performed on numerous Key Performance Indicators (KPIs). To prepare the evaluation meeting, managers have to gather data from Customer Relationship Management System, Financial Systems, Excel files, among others, leading to a very time-consuming process. The result of the Performance Evaluation is a classification followed by actions to improve the performance where it is needed. Nowadays, through predictive analytics technologies, it is possible to make classifications based on data. In this work, the authors applied a Naive Bayes model over a dataset that is composed by sales from 594 salespeople along 3 years from a global freight forwarding company, to classify salespeople into pre-defined categories provided by the business. The classification is done in 3 classes, being: Not Performing, Good, and Outstanding. The classification was achieved based on KPI’s like growth volume and percentage, sales variability along the year, opportunities created, customer base line, target achievement among others. The authors assessed the performance of the model with a confusion matrix and other techniques like True Positives, True Negatives, and F1 score. The results showed an accuracy of 92.50% for the whole modelinfo:eu-repo/semantics/publishedVersio