45 research outputs found
Accurate Inverter Error Compensation and Related Self-Commissioning Scheme in Sensorless Induction Motor Drives
No full textThis paper presents a technique for accurately identifying and compensating the inverter nonlinear voltage errors that deteriorate the performance of sensorless field-oriented controlled drives at low speed. The inverter model is more accurate than the standard signum-based models that are common in the literature, and the self-identification method is based on the feedback signal of the closed-loop flux observer in dc current steady-state conditions. The inverter model can be identified directly by the digital controller at the drive startup with no extra measures other than the motor phase currents and dc-link voltage. After the commissioning session, the compensation does not require to be tuned furthermore and is robust against temperature detuning. The experimental results, presented here for a rotor-flux-oriented SFOC IM drive for home appliances, demonstrate the feasibility of the proposed solution
Search for dark matter particles in W+ W− events with transverse momentum imbalance in proton-proton collisions at √s = 13 TeV
No full textA search for dark matter particles is performed using events with a pair of W bosons and large missing transverse momentum. Candidate events are selected by requiring one or two leptons (l = electrons or muons). The analysis is based on proton-proton collision data collected at a center-of-mass energy of 13 TeV by the CMS experiment at the LHC and corresponding to an integrated luminosity of 138 fb−1. No significant excess over the expected standard model background is observed in the lνqq and 2l2ν final states of the W+W− boson pair. Limits are set on dark matter production in the context of a simplified dark Higgs model, with a dark Higgs boson mass above the W+W− mass threshold. The dark matter phase space is probed in the mass range 100–300 GeV, extending the scope of previous searches. Current exclusion limits are improved in the range of dark Higgs masses from 160 to 250 GeV, for a dark matter mass of 200 GeV. © The Author(s) 2024
Observation of electroweak W+W- pair production in association with two jets in proton-proton collisions at 1as=13 TeV
No full textAbstract: An observation is reported of the electroweak production of a W+W- pair in association with two jets, with both W bosons decaying leptonically. The data sample corresponds to an integrated luminosity of 138 fb(-1) of proton-proton collisions at root s =13 TeV, collected by the CMS detector at the CERN LHC. Events are selected by requiring exactly two opposite-sign leptons (electrons or muons) and two jets with large pseudorapidity separation and high dijet invariant mass. Events are categorized based on the flavor of the final-state leptons. A signal is observed with a significance of 5.6 standard deviations (5.2 expected) with respect to the background-only hypothesis. The measured fiducial cross section is 10.2 +/- 2.0 fb and this value is consistent with the standard model prediction of 9.1 +/- 0.6 fb. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Variáveis associadas ao desempenho cognitivo tardio de pacientes com traumatismo crânio-encefálico grave
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Ciências MédicasObjetivos: O trauma cranioencefalico (TCE) e uma das principais causas de mortalidade e morbidade. Ha raros estudos prospectivos que investigam a associacao de variaveis clinicas e laboratoriais da fase aguda do TCE e o prognostico cognitivo tardio dos pacientes vitimas de TCE. Este estudo tem como objetivo identificar variaveis clinicas, laboratoriais e biomarcadores de lesao tecidual associados ao prognostico cognitivo em pacientes vitimas de TCE. Metodos: Foram coletadas prospectivamente as variaveis da internacao hospitalar de 234 pacientes consecutivos com TCE grave (GCS admissao . 8). Dos 172 sobreviventes, uma amostra representada de 46 pacientes realizaram avaliacao cognitiva (composta de 15 testes neuropsicologicos) em media 3 (+ - 1,8) anos apos a hospitalizacao. Um sub-grupo de 22 pacientes que foram avaliados cognitivamente realizaram analise dos niveis plasmaticos de TBARS (indicativo de dano por estresse oxidativo a lipideos) e Carbonil (indicador de dano por estresse oxidativo a proteinas) em amostras de sangue coletadas na fase aguda de TCE (mediana de 10, 30 e 70 horas apos o impacto do TCE). Um grupo controle (n=23) pareado por sexo, idade e nivel socio-educacional foi avaliado cognitivamente para comparacao com os pacientes. Resultados: A media de idade dos pacientes foi 34 (+ - 13) anos sendo 85% do sexo masculino, com escolaridade media de 9 (+ - 4,7) anos. Os pacientes apresentaram um desempenho inferior em todos os testes neuropsicologicos. A analise por regressao linear evidenciou uma forte associacao independente (R coeficiente = 0,6 a 0,8) entre maior escolaridade e menor idade e o desempenho cognitivo em 14 dos 15 testes neuropsicologicos avaliados. O desempenho nos testes cognitivos nao esteve associado ao genero, escore de admissao na Escala de Coma de Glasgow (ECG), exame das pupilas, presenca de trauma em outros orgaos, e classificacao da escala de Marshall na tomografia computadorizada na admissao (TC). Niveis elevados de glicose e presenca de hemorragia sub-aracnoide na TC mostraram-se independentemente associados a um menor desempenho no teste de Retencao de Aprendizagem de Rey e de Memoria Logica respectivamente. Embora os niveis plasmaticos de TBARS e Carbonil tenham sido significativamente elevados na fase aguda do TCE, estes biomarcadores nao se mostraram associados ao desempenho cognitivo dos pacientes. Conclusoes: Baixa escolaridade e idade mais avancada sao preditores independentes de pior desempenho cognitivo tardio apos o TCE grave. O exame de TC e glicemia mostraram limitada capacidade de predicao do desempenho cognitivo enquanto que o exame das pupilas, ECG na admissao, presenca de trauma associado nao foram preditores do desempenho em nenhum dos testes neuropsicologicos avaliados. A medida dos niveis plasmaticos de TBARS e Carbonil tambem nao se mostrou associada com o desempenho cognitivo dos pacientes. A identificacao de variaveis clinicas e laboratoriais associadas ao prognostico cognitivo apos o TCE grave permanece um desafio para a area de neuropsicologia clinica
Cadaveric Renal transplantation with Cyclosporine: Experiences in 148 patients at a single institution.
No full textProbing the relationship between electromagnetic ion cyclotron waves and plasmaspheric plumes near geosynchronous orbit
No full textPlasmaspheric plumes created during disturbed geomagnetic conditions have been suggested as a major cause of increased occurrences of electromagnetic ion cyclotron (EMIC) waves at these times. We have catalogued occurrences of strong Pc1 EMIC waves from 1996 through 2003 at three automated geophysical observatories operated by the British Antarctic Survey at auroral zone latitudes in Antarctica (L = 6.28, 7.68, and 8.07) and have compared them to the occurrence of plasmaspheric plumes in space, using simultaneous data from the Magnetospheric Plasma Analyzer on the Los Alamos National Laboratory 1990-095 spacecraft, in geosynchronous orbit at the same magnetic longitude. A superposed epoch analysis of these data was conducted for several categories of disturbed geomagnetic conditions, including magnetic storms, high-speed streams, and storm sudden commencements. We found only a weak correspondence between the occurrence of strong Pc1 waves observed on the ground and either plasmaspheric plumes or intervals of extended plasmasphere at geosynchronous orbit before, during, or after the onset of any of these categories. Strong Pc1 activity peaked near or slightly after local noon during all storm phases, consistent with equatorial observations by the Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer satellite at these L shells. The highest Pc1 occurrence probability was at or 1-2 days before storm onset and during the late recovery phase. Occurrence was lowest during the early recovery phase, consistent with the decrease in solar wind pressure often seen at this time. The peak at onset is consistent with earlier observations of waves in the outer magnetosphere stimulated by sudden impulses and magnetospheric compressions
ASO Author Reflections: Liver Failure Dominates the Risk of Failure to Rescue After Surgery for Perihilar Cholangiocarcinoma
No full textPAST
Failure to rescue (FTR) is increasingly used to evaluate the quality of postoperative care. Surgery for perihilar
cholangiocarcinoma (pCCA) carries one of the highest
risks among all elective cancer procedures, with the morbidity rate reaching 45–93% and the mortality rate reaching
6–18%.1
Whereas the predictors of morbidity and mortality
after pCCA surgery are well-known, the relevance of FTR
and its predictors in pCCA surgery are less defned.
PRESENT
In a large multicenter cohort of 2186 patients across
27 centers, the FTR rate was 24%,2
which is higher than
for other major abdominal cancer surgeries.3
Age, American Society of Anesthesiologists (ASA) score, jaundice at
presentation, right-side liver resections, and an annual hospital volume below six were identifed as predictors of FTR.
Postoperative liver failure dominated the risk of FTR in an
alternative model.
FUTURE
The huge impact of postoperative liver failure on FTR
emphasizes the need for proper patient selection and preoperative optimization to prevent primary liver failure, which
has a mortality rate of about 70%.4
Close postoperative
monitoring and rapid diagnostics to detect and treat complications seem essential to prevent secondary liver failure.4
Such a strategy has been shown to decrease mortality after
pancreatic surgery, and future studies should confrm its efcacy in high-risk liver surgery.5
Finally, the association of
hospital volume with FTR illustrates that it might help to
concentrate this rare and complex form of cancer surgery to
the highest-volume hepato-pancreato-biliary centers. Even
before surgery, outcomes can be detrimental, with a 40%
mortality rate after the initial biliary drainage attempt and
a median overall survival of only 5 months in a nationwide
all-inclusive cohort after diagnosis. The multi-disciplinary
experience and expertise in expert centers is likely to have a
positive impact on postoperative outcomes
