0000000001289780

AUTHOR

A. Almeida

showing 7 related works from this author

Critical Exponents and Randomness in SrTiO3 : Ca

1994

Since its discovery, the SrTiO3: Ca system is known to exhibit a number of features which were thought to arise from an impurity induced disorder. Non-linear dielectric measurements are used to obtain a more quantitative insight into this disorder. For 0.001 < xCa < 0.05, it is found that the non-linear susceptibility diverges at low temperatures. This is similar to what was previously reported in the dielectric random system KTaO3: Na. A method is proposed to quantify the contribution of the disorder to the non-linearities. It is found that the deviation from a true ferroelectric behaviour is not enough to call the low-temperature phase of SrTiO3: Ca a glass one. The maximum non-linearity …

Condensed matter physicsCritical phenomenaMineralogyDielectricCondensed Matter PhysicsFerroelectricityElectronic Optical and Magnetic MaterialsCondensed Matter::Materials ScienceDipolechemistry.chemical_compoundchemistryPhase (matter)Strontium titanateCritical exponentRandomnessphysica status solidi (b)
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Mean field behaviour of Sr1−xCaxTiO3

1996

A systematic analysis of the dielectric constant as a function of temperature in SrTiO 3 : Ca crystals with Ca content of 0.0020, 0.0032, 0.0055. 0.0058, and 0.0110 shows that the Barrett parameters are clearly modified by the Ca content. We have found for each Ca concentration the temperature below which the contribution of the Ca induced clusters becomes sizeable. The values obtained for the fitted parameters in the Barrett formula allow us to trace a boundary between the low-temperature quantum paraelectric and ferroelectric regimes.

PermittivityMaterials scienceCondensed matter physicsMineralogy02 engineering and technologyDielectricFunction (mathematics)021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesFerroelectricityElectronic Optical and Magnetic Materialschemistry.chemical_compoundchemistryMean field theory0103 physical sciencesStrontium titanate010306 general physics0210 nano-technologyQuantumphysica status solidi (b)
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Non-linear dielectric behaviour and glass phase in Sr1-xCaxTiO3(x= 0.002 andx= 0.003)

1999

This work reports a study of the temperature and electric field dependence of the dielectric constant of strontium calcium titanate. The first part of the paper is focused on the analysis of a mean-field model for the polar clusters generated by the random impurities of calcium. It is shown that the dipolar moments within each cluster can be represented by an equivalent quantum two-level system. General expressions for the temperature and field dependence of the Edward-Anderson order parameter and of the electrical polarization are given. Analytical solutions are also obtained in the limit of high temperatures and in the limit of high tunnelling frequencies. The second part of the work repo…

PermittivityCondensed matter physicsMineralogy02 engineering and technologyDielectric021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesFerroelectricitychemistry.chemical_compoundCalcium titanateDipolechemistryPhase (matter)Electric field0103 physical sciencesStrontium titanateGeneral Materials Science010306 general physics0210 nano-technologyJournal of Physics: Condensed Matter
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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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Early outcomes and complications following cardiac surgery in patients testing positive for coronavirus disease 2019: An international cohort study

2021

The outbreak of severe acute respiratory syndromecoronavirus-2, the cause of coronavirus disease 2019 (COVID-19) in December 2019 represented a global emergency accounting for more than 2.5 million deaths worldwide.1 It has had an unprecedented influence on cardiac surgery internationally, resulting in cautious delivery of surgery and restructuring of services.2 Understanding the influence of COVID-19 on patients after cardiac surgery is based on assumptions from other surgical specialties and single-center studies. The COVIDSurg Collaborative conducted a multicenter cohort study, including 1128 patients, across 235 hospitals, from 24 countries demonstrating perioperative COVID-19 infection…

Pulmonary and Respiratory MedicineMale2019-20 coronavirus outbreakmedicine.medical_specialtyCoronavirus disease 2019 (COVID-19)Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)complication.ArticleNOCohort Studiesoutcomes; complications; following cardiac surgery; coronavirus disease 2019Postoperative ComplicationsCardiovascular Diseases; Cohort Studies; Female; Humans; Male; Middle Aged; SARS-CoV-2; COVID-19; Cardiac Surgical Procedures; Postoperative ComplicationsInternal medicineCardiovascular DiseasemedicineCardiac Surgical ProcedureHumansIn patientCardiac Surgical ProceduresLS7_4business.industrySARS-CoV-2COVID-19Middle AgedCardiac surgeryCardiovascular DiseasesoutcomeSurgeryFemaleCohort StudieCardiology and Cardiovascular Medicinebusinesscardiac surgery[SDV.MHEP]Life Sciences [q-bio]/Human health and pathologyCohort studyHuman
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Machine learning risk prediction of mortality for patients undergoing surgery with perioperative SARS-CoV-2: the COVIDSurg mortality score

2021

The British journal of surgery 108(11), 1274-1292 (2021). doi:10.1093/bjs/znab183

Cuidado perioperatorioAcademicSubjects/MED00910Settore MED/18 - CHIRURGIA GENERALEMedizinpulmonary complicationspreoperative screeningDatasets as TopicSurgical Procedures Operative/mortality030230 surgeryperioperative care ; surgical procedures ; operative mortality ; machine learning ; sars-cov-2Medical and Health SciencesProcediments quirúrgicsCohort StudiesMachine LearningTumours of the digestive tract Radboud Institute for Health Sciences [Radboudumc 14]0302 clinical medicineModelsProcedimientos quirúrgicosMedicine and Health SciencesCOVIDSurg Collaborative Co-authorsMedicine030212 general & internal medicineskin and connective tissue diseasesRapid Research Communication11 Medical and Health SciencesOperative/mortalitySARS-CoV-19COVID-19/mortalityStatisticalCOVID-19/mortality; Cohort Studies; Datasets as Topic; Humans; Machine Learning; Models Statistical; Risk Assessment; SARS-CoV-2; Surgical Procedures Operative/mortalityCOVID-19; Cohort Studies; Datasets as Topic; Humans; Machine Learning; SARS-CoV-2; Surgical Procedures Operative; Models Statistical; Risk AssessmentAprendizaje automáticoOperativeSurgical Procedures OperativeoutcomeOperativo[SDV.IB]Life Sciences [q-bio]/BioengineeringPatient SafetyAcademicSubjects/MED000106.4 SurgeryLife Sciences & BiomedicineHuman61medicine.medical_specialty616.9Coronavirus disease 2019 (COVID-19)Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-.Risk AssessmentNOCOVIDSurg CollaborativeVaccine Related03 medical and health sciencesClinical ResearchBiodefenseCures perioperatòriesAprenentatge automàticMortalitatHumansOperatiusLS7_4Surgical ProceduresScience & TechnologyModels Statisticalbusiness.industrySARS-CoV-2SARS-CoV-2 infectionKirurgiPreventionnot indicatedcovid 19fungiEvaluation of treatments and therapeutic interventionsCOVID-19Perioperativecovid 19; pulmonary complications; postoperative mortality risk; SARS-CoV-2 infection; preoperative screening; vaccinationvaccinationmortalityGood Health and Well BeingMortalidadEmergency medicineSurgeryHuman medicineCohort Studiebusinesspostoperative mortality riskPerioperative care
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A multicenter randomized trial for quality of life evaluation by non-invasive intelligent tools during post-curative treatment follow-up for head and…

2023

Patients surviving head and neck cancer (HNC) suffer from high physical, psychological, and socioeconomic burdens. Achieving cancer-free survival with an optimal quality of life (QoL) is the primary goal for HNC patient management. So, maintaining lifelong surveillance is critical. An ambitious goal would be to carry this out through the advanced analysis of environmental, emotional, and behavioral data unobtrusively collected from mobile devices. The aim of this clinical trial is to reduce, with non-invasive tools (i.e., patients' mobile devices), the proportion of HNC survivors (i.e., having completed their curative treatment from 3 months to 10 years) experiencing a clinically relevant r…

Settore M-PSI/01 - Psicologia GeneraleBD4QoL; QOL; android; head and neck cancer; mHealth; survivorship; unobtrusiveQOLmHealthSettore MED/06 - Oncologia Medicahead and neck cancerBD4QoLandroidunobtrusivesurvivorshipFrontiers in Oncology
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