0000000000574164

AUTHOR

M. Barreda

showing 4 related works from this author

Rigid motions relative to an observer:L-rigidity

1996

A new definition of rigidity,L-rigidity, in general relativity is proposed. This concept is a special class of pseudorigid motions and therefore it depends on the chosen curveL. It is shown that, for slow-rotation steady motions in Minkowski space, weak rigidity andL-rigidity are equivalent. The methods of the PPN approximation are considered. In this formalism, the equations that characterizeL-rigidity are expressed. As a consequence, the baryon mass density is constant in first order, the stress tensor is constant in the comoving system, the Newtonian potential is constant along the lineL, and the gravitational field is constant along the lineL in the comoving system.

PhysicsGeneral Relativity and Quantum CosmologyMathematics of general relativityRigidity (electromagnetism)Classical mechanicsNewtonian potentialPhysics and Astronomy (miscellaneous)Gravitational fieldGeneral relativityCauchy stress tensorGeneral MathematicsMinkowski spaceIntroduction to the mathematics of general relativityInternational Journal of Theoretical Physics
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Relation between quasirigidity andL-rigidity in space-times of constant curvature and weak fields

1997

The relation between quasirigidity andL-rigidity in space-times of constant nonzero curvature and in space-times with small curvature (weak fields) is studied. The covariant expansion of bitensors about a point is considered. We obtain an increase in the order of magnitude, underL-rigidity conditions, of the rate of change with respect to a comoving orthonormal frame of the linear momentum, angular momentum, and reduced multipole moments of the energy-momentum tensor. Thus,L-rigidity leads to quasirigidity in such space-times.

Weyl tensorPhysicsAngular momentumRiemann curvature tensorPhysics and Astronomy (miscellaneous)General MathematicsCurvatureConstant curvaturesymbols.namesakeClassical mechanicsTotal angular momentum quantum numbersymbolsAngular momentum operatorMathematical physicsScalar curvatureInternational Journal of Theoretical Physics
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L-Rigidity in Newtonian approximation

2008

Newtonian limit of L-Rigidity is obtained. In this formalism, L-Rigidity is reduced to steady Newtonian rigid motions in a Newtonian frame of reference in which the observer is at rest.

PhysicsPhysics::General PhysicsInertial frame of referenceNewtonian potentialNewtonian limitRotating reference frameFrame of referenceCovariant derivativePhysics::Fluid DynamicsGeneral Relativity and Quantum CosmologyClassical mechanicsPhysics::Space PhysicsNewtonian fluidVector field
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SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

2021

Abstract Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in su…

MaleCOVID-19 Vaccinesafe surgery; vaccination modelling; COVID-19Vascular damage Radboud Institute for Health Sciences [Radboudumc 16]MULTICENTERComorbidity030230 surgery0302 clinical medicinephase 3 clinical trial (topic)Case fatality rateProspective StudiesSARS-CoV-2 Vaccination Safe surgeryCOVID-19/epidemiologySARS-CoV-2 ; vaccination ; safe surgeryeducation.field_of_studycase fatality rateVaccinationVaccinationAdolescent; Adult; Aged; COVID-19; COVID-19 Vaccines; Comorbidity; Elective Surgical Procedures; Female; Humans; Male; Middle Aged; Postoperative Complications; Preoperative Period; Prospective Studies; SARS-CoV-2; Vaccination; Young Adulthealth care policyElective Surgical Procedures030220 oncology & carcinogenesisvaccination modellingPreoperative PeriodCOVID-19; SARS-CoV-2; cancer; vaccination; outcome; mortality; infection; modellingCohort studyprospective studyHumanmedicine.medical_specialtyArticle03 medical and health sciencesSARS-CoV-2 vaccinationSDG 3 - Good Health and Well-beingCOVID-19 Vaccines/pharmacologyHumansVaccination/methodsElective surgeryeducationAgedScience & TechnologyElective Surgical Procedureadult; aged; Article; cancer grading; cancer surgery; case fatality rate; computer assisted tomography; elective surgery; female; follow up; health care policy; human; incidence; infection rate; infection risk; major clinical study; male; middle aged; mortality; outcome assessment; phase 3 clinical trial (topic); preoperative care; prospective study; sensitivity analysis; seroprevalence; Severe acute respiratory syndrome coronavirus 2; vaccination; young adult; COVID-19; COVID-19 Vaccines; Comorbidity; Elective Surgical Procedures; Postoperative Complications; Preoperative Period; SARS-CoV-2; Vaccination; surgery.Cura preoperatòriamajor clinical studymortalityinfectionProspective StudieincidenceSurgeryHuman medicinePostoperative Complication610 Medizin und GesundheitAcademicSubjects/MED00910Settore MED/18 - CHIRURGIA GENERALESettore MED/29 - CHIRURGIA MAXILLOFACCIALEcomputer assisted tomographyESTUDOS PROSPECTIVOSsurgerysafe surgeryPostoperative Complicationssensitivity analysisSevere acute respiratory syndrome coronavirus 2preoperative careVacunacióProspective cohort studyseroprevalenceIncidence (epidemiology)covidElective Surgical Procedures/methodsMiddle Agedcancer gradingCOVID vaccinationoutcome/dk/atira/pure/sustainabledevelopmentgoals/good_health_and_well_beingSARS-CoV-2; vaccination; surgeryOriginal ArticleFemalecancer surgeryAcademicSubjects/MED00010Life Sciences & BiomedicineAdultCOVID-19 VaccinesAdolescentinternational prospective cohort studyPostoperative Complications/prevention & controlPopulationinfection rateSARS-CoV-2/immunologyNOmodellingYoung Adultmedicinefollow upcancerddc:610infection riskoutcome assessmentLS7_4business.industrySARS-CoV-2Number needed to vaccinatePreoperative careCOVID-193126 Surgery anesthesiology intensive care radiologySettore MED/18Reconstructive and regenerative medicine Radboud Institute for Health Sciences [Radboudumc 10]elective surgeryEmergency medicinebusiness[SDV.MHEP]Life Sciences [q-bio]/Human health and pathologyThe British Journal of Surgery
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