76 research outputs found
Supersymmetric Many-particle Quantum Systems with Inverse-square Interactions
The development in the study of supersymmetric many-particle quantum systems
with inverse-square interactions is reviewed. The main emphasis is on quantum
systems with dynamical OSp(2|2) supersymmetry. Several results related to
exactly solved supersymmetric rational Calogero model, including shape
invariance, equivalence to a system of free superoscillators and non-uniqueness
in the construction of the Hamiltonian, are presented in some detail. This
review also includes a formulation of pseudo-hermitian supersymmetric quantum
systems with a special emphasis on rational Calogero model. There are quite a
few number of many-particle quantum systems with inverse-square interactions
which are not exactly solved for a complete set of states in spite of the
construction of infinitely many exact eigen functions and eigenvalues. The
Calogero-Marchioro model with dynamical SU(1,1|2) supersymmetry and a quantum
system related to short-range Dyson model belong to this class and certain
aspects of these models are reviewed. Several other related and important
developments are briefly summarized.Comment: LateX, 65 pages, Added Acknowledgment, Discussions and References,
Version to appear in Jouranl of Physics A: Mathematical and Theoretical
(Commissioned Topical Review Article
"Mushroom cloud": a giant left ventricular pseudoaneurysm after a myocardial infarction due to myocardial bridging – a case report
Left ventricular pseudoaneurysm is an uncommon complication after transmural myocardial infarction, occurring when a free wall rupture is contained by adhesions of the overlying pericardium preventing acute tamponade. In this report, an unusual case of a 61 year-old male with a giant apical left ventricular pseudoaneurysm after an unnoticed myocardial infarction is presented. On coronary angiogram myocardial bridging of the distal left anterior descending artery was judged to be the infarct related lesion. The echocardiographic diagnosis allowed for a timely surgical intervention which resulted in the patient's full recovery
5. Impacto del cambio climático en la sedimentación y en la acumulación de carbono en los lagos de la Amazonia peruana
Los suelos, las aguas y los sedimentos de la cuenca amazĂłnica son importantes compartimentos del ciclo de carbono, el cual se encuentra parcialmente almacenado en los bosques inundables y en los lagos de inundaciĂłn de la regiĂłn (20% de la superficie total de la cuenca). Estudiar los procesos de sedimentaciĂłn lacustres a diferentes escalas espaciales y de tiempo permite mejorar le estimaciĂłn del balance biogeoquĂmico del carbono (uno de los gases de efecto Invernadero responsable del cambio climático actual, el CO2). Las tasas de sedimentaciĂłn en las áreas de inundaciĂłn dependen de varios factores, como el tipo de agua de los lagos y del tipo de conexiĂłn que tienen con los rĂos. El análisis en laboratorio de muestras de sedimentos, que mantienen la secuencia de deposiciĂłn, sirve para determinar las condiciones geolĂłgicas, meteorolĂłgicas, los cambios en el ecosistema e incluso acciones de origen humano que pueden haber afectado los regĂmenes de sedimentaciĂłn y la composiciĂłn de los sedimentos a lo largo del tiempo.Les sols, les eaux et les sĂ©diments du bassin amazonien sont des compartiments importants du cycle du carbone, qui est partiellement stockĂ© dans les forĂŞts et les lacs inondĂ©s dans la rĂ©gion (20% de la superficie totale du bassin). ConnaĂ®tre les processus de sĂ©dimentation lacustres Ă diffĂ©rentes Ă©chelles spatiales et temporelles permet d'amĂ©liorer l'estimation de l'Ă©quilibre biogĂ©ochimique du carbone (un des gaz responsables du changement climatique actuel, CO2). Les taux de sĂ©dimentation dans la plaine inondable dĂ©pendent de plusieurs facteurs, y compris le type d'eau des lacs et le type de connexion avec les rivières. Les analyses de laboratoire des Ă©chantillons de sĂ©diments, qui maintiennent la sĂ©quence de dĂ©pĂ´t, sont utilisĂ©es pour dĂ©terminer les caractĂ©ristiques gĂ©ologiques, les conditions mĂ©tĂ©orologiques, les changements dans l'Ă©cosystème et mĂŞme les actions humaines qui peuvent avoir une incidence sur les rĂ©gimes de sĂ©dimentation et la composition des sĂ©diments au fil du temps.The soils, waters and sediments of the Amazon basin are important compartments of the carbon cycle, which are partially stored in flooded forests and lakes of flooding in the region (20% of the total basin area). The study of lacustrine sedimentation processes at different spatial and temporal scales allows improving the estimation of biogeochemical carbon balance (one of the greenhouse gases responsible for the current climate change, CO2). Sedimentation rates in flood areas depend on several factors, such as the type of water from lakes and the type of connection this water has with rivers. The laboratory analysis of sediment samples, which maintain the deposition sequence, is used to determine geological and meteorological conditions; as well as changes in the ecosystem, even actions arising from humans that may have affected the sedimentation regimes and sediment composition along the time
A review of unmanned vehicles for the detection and monitoring of marine fauna
Recent technology developments have turned present-day unmanned systems into realistic alternatives to traditional marine animal survey methods. Benefits include longer survey durations, improved mission safety, mission repeatability, and reduced operational costs. We review the present status of unmanned vehicles suitable for marine animal monitoring conducted in relation to industrial offshore activities, highlighting which systems are suitable for three main monitoring types: population, mitigation, and focal animal monitoring. We describe the technical requirements for each of these monitoring types and discuss the operational aspects. The selection of a specific sensor/platform combination depends critically on the target species and its behaviour. The technical specifications of unmanned platforms and sensors also need to be selected based on the surrounding conditions of a particular offshore project, such as the area of interest, the survey requirements and operational constraints
Giant Magnons in AdS4 x CP3: Embeddings, Charges and a Hamiltonian
This paper studies giant magnons in CP3, which in all known cases are old
solutions from S5 placed into two- and three-dimensional subspaces of CP3,
namely CP1, RP2 and RP3. We clarify some points about these subspaces, and
other potentially interesting three- and four-dimensional subspaces. After
confirming that E-(J1-J4)/2 is a Hamiltonian for small fluctuations of the
relevant 'vacuum' point particle solution, we use it to calculate the
dispersion relation of each of the inequivalent giant magnons. We comment on
the embedding of finite-J solutions, and use these to compare string solutions
to giant magnons in the algebraic curve.Comment: 17 pages (plus appendices) and 1 figure. v2 has new discussion of
placing finite-J giant magnons into CP^3, adds many references, and corrects
a few typo
Looking through the QCD conformal window with perturbation theory
We study the conformal window of QCD using perturbation theory, starting from the perturbative upper edge and going down as much as we can towards the strongly coupled regime. We do so by exploiting the available five-loop
computation of the -function and employing Borel resummation techniques both for the ordinary perturbative series and for the Banks-Zaks conformal expansion. Large- results are also used. We argue that the perturbative series for the -function is most likely asymptotic and non-Borel resummable, yet Borel resummation techniques allow to improve on ordinary perturbation theory. We find
substantial evidence that QCD with flavours flows in the IR to a conformal field theory. Though the evidence is weaker, we find indications that also might sit within the conformal window. We also compute the value
of the mass anomalous dimension at the fixed point and compare it with the available lattice results. The conformal window might extend for lower values of , but our methods break down for n_f<11, where we expect that non-perturbative effects become important. A similar analysis is performed in the Veneziano limit
Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.
PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks
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