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1.
Proc Natl Acad Sci U S A ; 121(42): e2317375121, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-39378084

RESUMEN

The detection of numerous and relatively bright galaxies at redshifts z > 9 has prompted new investigations into the star-forming properties of high-redshift galaxies. Using local forms of the initial mass function (IMF) to estimate stellar masses of these galaxies from their light output leads to galaxy masses that are at the limit allowed for the state of the Lambda Cold Dark Matter (ΛCDM) Universe at their redshift. We explore how varying the IMF assumed in studies of galaxies in the early universe changes the inferred values for the stellar masses of these galaxies. We infer galaxy properties with the spectral energy distribution (SED) fitting code Prospector using varying IMF parameterizations for a sample of 102 galaxies with photometry from the James Webb Space Telescope, JWST Advanced Deep Extragalactic Survey that are spectroscopically confirmed to be at [Formula: see text], with additional photometry from the JWST Extragalactic Medium Band Survey for twenty-one of the galaxies. We demonstrate that models with stellar masses reduced by a factor of three or more do not affect the modeled SED.

2.
Proteins ; 92(6): 691-692, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38197126

RESUMEN

This is a short appreciation of the contributions made by E. James Milner-White to the field of protein structure, in particular his description of small hydrogen-bonded motifs.


Asunto(s)
Enlace de Hidrógeno , Proteínas , Historia del Siglo XX , Proteínas/química , Proteínas/metabolismo , Historia del Siglo XXI , Conformación Proteica , Humanos , Modelos Moleculares
3.
Breast Cancer Res Treat ; 208(1): 215-222, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38914917

RESUMEN

PURPOSE: To use robust consensus methods with individuals with lived breast cancer experience to agree the top 10 research priorities to improve information and support for patients undergoing breast cancer surgery in the UK. METHODS: Research uncertainties related to information and support for breast cancer surgery submitted by patients and carers were analysed thematically to generate summary questions for inclusion in an online Delphi survey. Individuals with lived breast cancer experience completed two Delphi rounds including feedback in which they selected their top 10 research priorities from the list provided. The most highly ranked priorities from the survey were discussed at an in-person prioritisation workshop at which the final top 10 was agreed. RESULTS: The 543 uncertainties submitted by 156 patients/carers were categorised into 63 summary questions for inclusion in the Delphi survey. Of the 237 individuals completing Round 1, 190 (80.2%) participated in Round 2. The top 25 survey questions were carried forward for discussion at the in-person prioritisation workshop at which 17 participants from across the UK agreed the final top 10 research priorities. Key themes included ensuring patients were fully informed about all treatment options and given balanced, tailored information to support informed decision-making and empower their recovery. Equity of access to treatments including contralateral mastectomy for symmetry was also considered a research priority. CONCLUSION: This process has identified the top 10 research priorities to improve information and support for patients undergoing breast cancer surgery. Work is now needed to develop studies to address these important questions.


Asunto(s)
Neoplasias de la Mama , Técnica Delphi , Mastectomía , Humanos , Neoplasias de la Mama/cirugía , Femenino , Reino Unido , Encuestas y Cuestionarios , Persona de Mediana Edad , Adulto , Atención Dirigida al Paciente , Investigación , Educación del Paciente como Asunto/métodos , Anciano , Toma de Decisiones
4.
Glob Chang Biol ; 30(1): e17047, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38273534

RESUMEN

Decreased body size is often cited as a major response to ocean warming. Available evidence, however, questions the actual emergence of shrinking trends and the prevalence of temperature-driven changes in size over alternative drivers. In marine fish, changes in food availability or fluctuations in abundance, including those due to size-selective fishing, provide compelling mechanisms to explain changes in body size. Here, based on three decades of scientific survey data (1990-2021), we report a decline in the average body size-length and weight-of anchovy, Engraulis encrasicolus L., in the Bay of Biscay. Shrinking was evident in all age classes, from juveniles to adults. Allometric adjustment indicated slightly more pronounced declines in weight than in total length, which is consistent with a change toward a slender body shape. Trends in adult weight were nonlinear, with rates accelerating to an average decline of up to 25% decade-1 during the last two decades. We found a strong association between higher anchovy abundance and reduced juvenile size. The effect of density dependence was less clear later in life, and temperature became the best predictor of declines in adult size. Theoretical analyses based on a strategic model further suggested that observed patterns are consistent with a simultaneous, opposing effect of rising temperatures on accelerating early growth and decreasing adult size as predicted by the temperature-size rule. Macroecological assessment of ecogeographical-Bergmann's and James'-rules in anchovy size suggested that the observed decline largely exceeds intraspecific variation and might be the result of selection. Limitations inherent in the observational nature of the study recommend caution and a continued assessment and exploration of alternative drivers. Additional evidence of a climate-driven regime shift in the region suggests, however, that shrinking anchovy sizes may signal a long-lasting change in the structure and functioning of the Bay of Biscay ecosystem.


Asunto(s)
Bahías , Ecosistema , Animales , Clima , Temperatura , Tamaño Corporal/fisiología , Alimentos Marinos
5.
Artículo en Inglés | MEDLINE | ID: mdl-38289223

RESUMEN

The taxonomic status of strain P5891T, isolated from an Adélie penguin beak swab, was investigated. Based on the 16S rRNA gene sequence, the strain was identified as a potentially novel Corynebacterium species, with the highest sequence similarities to Corynebacterium rouxii FRC0190T (96.7 %) and Corynebacterium epidermidicanis DSM 45586T (96.6 %). The average nucleotide identity values between strain P5891T and C. rouxii FRC0190T and C. epidermidicanis DSM 45586T were 68.2 and 69.2 %, respectively. The digital DNA-DNA hybridization values between strain P5891T and C. rouxii FRC0190T and C. epidermidicanis DSM 45586T were 23.7 and 21.4 %, respectively. Phylogenetic trees based on the 16S rRNA sequence placed strain P5891T in a separate branch with Corynebacterium canis 1170T and Corynebacterium freiburgense 1045T, while a phylogenomic tree based on the Corynebacterium species core genome placed the strain next to Corynebacterium choanae 200CHT. Extensive phenotyping and genomic analyses clearly confirmed that strain P5891T represents a novel species of the genus Corynebacterium, for which the name Corynebacterium mendelii sp. nov. is proposed, with the type strain P5891T (=CCM 8862T=LMG 31627T).


Asunto(s)
Spheniscidae , Animales , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , ADN Bacteriano/genética , Técnicas de Tipificación Bacteriana , Composición de Base , Ácidos Grasos/química , Bacterias , Corynebacterium/genética , Boca
6.
Biometrics ; 80(3)2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-39101548

RESUMEN

We consider the setting where (1) an internal study builds a linear regression model for prediction based on individual-level data, (2) some external studies have fitted similar linear regression models that use only subsets of the covariates and provide coefficient estimates for the reduced models without individual-level data, and (3) there is heterogeneity across these study populations. The goal is to integrate the external model summary information into fitting the internal model to improve prediction accuracy. We adapt the James-Stein shrinkage method to propose estimators that are no worse and are oftentimes better in the prediction mean squared error after information integration, regardless of the degree of study population heterogeneity. We conduct comprehensive simulation studies to investigate the numerical performance of the proposed estimators. We also apply the method to enhance a prediction model for patella bone lead level in terms of blood lead level and other covariates by integrating summary information from published literature.


Asunto(s)
Simulación por Computador , Humanos , Modelos Lineales , Biometría/métodos , Plomo/sangre , Rótula , Modelos Estadísticos , Interpretación Estadística de Datos
7.
J Anim Ecol ; 2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-39030760

RESUMEN

Variation in heat tolerance among populations can determine whether a species is able to cope with ongoing climate change. Such variation may be especially important for ectotherms whose body temperatures, and consequently, physiological processes, are regulated by external conditions. Additionally, differences in body size are often associated with latitudinal clines, thought to be driven by climate gradients. While studies have begun to explore variation in body size and heat tolerance within species, our understanding of these patterns across large spatial scales, particularly regarding the roles of plasticity and genetic differences, remains incomplete. Here, we examine body size, as measured by wing length, and thermal tolerance, as measured by the time to immobilisation at high temperatures ("thermal knockdown"), in populations of the mosquito Aedes sierrensis collected from across a large latitudinal climate gradient spanning 1300 km (34-44° N). We find that mosquitoes collected from lower latitudes and warmer climates were more tolerant of high temperatures than those collected from higher latitudes and colder climates. Moreover, body size increased with latitude and decreased with temperature, a pattern consistent with James' rule, which appears to be a result of plasticity rather than genetic variation. Our results suggest that warmer environments produce smaller and more thermally tolerant populations.

8.
Can J Neurol Sci ; 51(1): 117-121, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36710572

RESUMEN

Dr. Sharpe was a leading eye movement researcher who had also been the editor of this journal. We wish to mark the 10th anniversary of his death by providing a sense of what he had achieved through some examples of his research.


Asunto(s)
Neurología , Oftalmología , Humanos , Masculino , Oftalmología/historia
9.
Transfus Med ; 2024 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-38515397

RESUMEN

The obstetrician James Blundell performed the first human-to-human blood transfusion in England during the early part of the 19th century arguing that it could be used as a treatment for post-partum haemorrhage. During this period, Blundell personally acknowledged two of his medical colleagues Charles Waller and Edward Doubleday as being strong supporters of the use of blood transfusion. This paper outlines the roles that these two men played in the early history of blood transfusion.

10.
Health Expect ; 27(5): e70055, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39382158

RESUMEN

BACKGROUND AND AIM: User participation is a prerequisite for receiving research funding in healthcare in Norway. Despite many positive benefits, studies report challenges from users' and researchers' perspectives. Limited knowledge exists concerning researchers' experiences in scenarios where the users are professionals within healthcare and research. The aim of this retrospective study was to explore and reflect on personal experiences as researchers from a process of planning and developing research questions for a PhD project, following the James Lind Alliance guidelines, which were a requirement for funding. We focused on how the process of collaboration with a specific group of users influenced the researchers' sense of selves. DESIGN AND METHOD: We used a qualitative design based on collaborative autoethnography, exploring personal experiences from a sociocultural point of view. Two of the three researchers in the team recollected their experiences from the user involvement process while applying the James Lind Alliance guidelines. We used different data sources to develop two autoethnographic narratives. The narratives were analysed using thematic analysis. RESULTS: The autoethnographic narratives demonstrate the complexity of user involvement from the researchers' perspectives. We identified four themes in the analysis: intrinsic and extrinsic motivation, competing paradigms, hierarchy and dual roles. The accounts illustrated the researchers' ambivalence within the process, indicating that they feared a loss of control over the direction of the research project. The narratives visualised a struggle to appear as credible researchers, illustrating how the involvement of a specific group of users and adherence to a specific guideline for user involvement influenced the researchers' experiences of their roles and identities in the collaboration. CONCLUSION: The results point to the relevance of the sociocultural backdrop; researchers might become frontline providers of policy implementation in research, balancing tensions between regulatory constraints, user involvement and researchers' professional identity and research ideals, when a specific, detailed procedure for user involvement is required. PATIENT OR PUBLIC CONTRIBUTION: Two user panels comprising participants from clinical practice, education and research, along with a service user, collaborated in the planning and development of research questions for a PhD project. This autoethnographic study elaborates this process.


Asunto(s)
Antropología Cultural , Conducta Cooperativa , Investigación Cualitativa , Investigadores , Humanos , Investigadores/psicología , Noruega , Estudios Retrospectivos , Participación del Paciente , Motivación , Guías como Asunto , Femenino , Masculino
11.
Entropy (Basel) ; 26(10)2024 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-39451936

RESUMEN

Empirical Bayes-based Methods (EBM) is an increasingly popular form of Objective Bayesianism (OB). It is identified in particular with the statistician Bradley Efron. The main aims of this paper are, first, to describe and illustrate its main features and, second, to locate its role by comparing it with two other statistical paradigms, Subjective Bayesianism (SB) and Evidentialism. EBM's main formal features are illustrated in some detail by schematic examples. The comparison between what Efron calls their underlying "philosophies" is by way of a distinction made between confirmation and evidence. Although this distinction is sometimes made in the statistical literature, it is relatively rare and never to the same point as here. That is, the distinction is invariably spelled out intra- and not inter-paradigmatically solely in terms of one or the other accounts. The distinction made in this paper between confirmation and evidence is illustrated by two well-known statistical paradoxes: the base-rate fallacy and Popper's paradox of ideal evidence. The general conclusion reached is that each of the paradigms has a basic role to play and all are required by an adequate account of statistical inference from a technically informed and fine-grained philosophical perspective.

12.
Breast Cancer Res Treat ; 197(1): 39-49, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36319906

RESUMEN

PURPOSE: A James Lind Alliance priority setting partnership was developed to identify research priorities in breast cancer surgery from individuals with lived experience, at high genetic risk of breast cancer, and healthcare professionals (HCPs). METHODS: 'Uncertainties' were collected using an online survey. Following an evidence check and development of summary questions, an interim survey asked participants to rank their top 10 research priorities from the question list. Top-ranked questions from patient/carer, high-risk and professional groups were carried forward for discussion to a final online prioritisation workshop. RESULTS: 260 participants (101 patients/carers, 156 HCPs) submitted 940 uncertainties via the initial survey. These were analysed thematically into 128 summary questions in six topic areas. Following evidence checking, 59 questions were included in the interim survey which was completed by 572 respondents. Marked differences were seen in questions prioritised by patients/carers, HCPs and women at high-risk. The top eight priorities in patient/carer and professional groups and top two priorities for high-risk women were carried forward to the online workshop at which 22 participants discussed and agreed the final top 10. Key themes included de-escalation of breast and axillary surgery, factors impacting the development/detection of locoregional recurrence and optimal provision of support for informed treatment decision-making. CONCLUSION: The top 10 research priorities in breast cancer surgery have been agreed. However, the observed differences in research priorities identified by patients and professional groups were not anticipated. Top priorities from both groups should inform future UK breast cancer surgical research, to ensure that it addresses questions that are important to breast cancer community as a whole.


Asunto(s)
Investigación Biomédica , Neoplasias de la Mama , Humanos , Femenino , Neoplasias de la Mama/cirugía , Prioridades en Salud , Recurrencia Local de Neoplasia , Encuestas y Cuestionarios , Reino Unido
13.
Rheumatology (Oxford) ; 62(8): 2716-2723, 2023 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-36453848

RESUMEN

OBJECTIVES: To identify and prioritize the top 10 research questions for PsA. METHODS: The British Psoriatic Arthritis Consortium (BritPACT) formed a Priority Setting Partnership (PSP) comprising of people living with PsA, carers and clinicians, supported by the James Lind Alliance (JLA). This PSP followed the established three-stage JLA process: first, an online survey of people living with PsA, carers and clinicians to identify PsA questions, asking, 'What do you think are the most important unanswered questions in psoriatic arthritis research?' The questions were checked against existing evidence to establish 'true uncertainties' and grouped as 'indicative questions' reflecting the overarching themes. Then a second online survey ranked the 'true uncertainties' by importance. Finally, a workshop including people living with PsA and clinician stakeholders finalized the top 10 research priorities. RESULTS: The initial survey attracted 317 respondents (69% people living with PsA, 15% carers), with 988 questions. This generated 46 indicative questions. In the second survey, 422 respondents (78% people living with PsA, 4% carers) prioritized these. Eighteen questions were taken forward to the final online workshop. The top unanswered PsA research question was 'What is the best strategy for managing patients with psoriatic arthritis including non-drug and drug treatments?' Other top 10 priorities covered diagnosis, prognosis, outcome assessment, flares, comorbidities and other aspects of treatment (https://www.jla.nihr.ac.uk). CONCLUSION: The top 10 priorities will guide PsA research and enable PsA researchers and those who fund research to know the most important questions for people living with PsA.


Asunto(s)
Artritis Psoriásica , Investigación Biomédica , Humanos , Artritis Psoriásica/terapia , Prioridades en Salud , Evaluación de Resultado en la Atención de Salud , Encuestas y Cuestionarios , Cuidadores
14.
Biometrics ; 79(4): 3929-3940, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37458679

RESUMEN

In this paper, we analyze the length-biased and partly interval-censored data, whose challenges primarily come from biased sampling and interfere induced by interval censoring. Unlike existing methods that focus on low-dimensional data and assume the covariates to be precisely measured, sometimes researchers may encounter high-dimensional data subject to measurement error, which are ubiquitous in applications and make estimation unreliable. To address those challenges, we explore a valid inference method for handling high-dimensional length-biased and interval-censored survival data with measurement error in covariates under the accelerated failure time model. We primarily employ the SIMEX method to correct for measurement error effects and propose the boosting procedure to do variable selection and estimation. The proposed method is able to handle the case that the dimension of covariates is larger than the sample size and enjoys appealing features that the distributions of the covariates are left unspecified.


Asunto(s)
Tamaño de la Muestra , Análisis de Supervivencia , Simulación por Computador
15.
Respirology ; 28(7): 636-648, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36921924

RESUMEN

BACKGROUND AND OBJECTIVE: People living with asthma, their carers, clinicians and policymakers are the end-users of research and need research that address their individual healthcare needs. We aimed to understand the research priorities of end-users of asthma research. METHODS: A national cross-sectional mixed-methods study was conducted. The study included an online survey that engaged patients, carers, healthcare professionals and policymakers to provide statements to free-text questions about what they would like to see answered by research to improve living with asthma on a day-to-day basis. Responses where thematically analysed followed by three online priority setting consensus workshops. RESULTS: There were 593 respondents who provided 1446 text comments. Participants prioritized 10 asthma research themes which were: (1) asthma in children, (2) COVID 19 and asthma, (3) asthma care and self-management, (4) diagnosis and medication, (5) managing asthma attacks, (6) causes, prevention and features of asthma, (7) mental health, (8) asthma and ageing, (9) severe asthma, (10) asthma and other health conditions. Each theme comprises specific research questions. CONCLUSION: This project successfully established 10 priority research themes for asthma, reflecting the collective voice of the end-users of this research. These novel data can be used to address the documented mismatch in research prioritization between the research community and the end-users of research.


Asunto(s)
Investigación Biomédica , COVID-19 , Niño , Humanos , Cuidadores , Estudios Transversales , COVID-19/epidemiología , Personal de Salud , Encuestas y Cuestionarios
16.
J Endocrinol Invest ; 46(11): 2421-2422, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36952214

RESUMEN

This manuscript presents some artistic and medical considerations about a representation of an individual with apparent dwarfism. He was found in Saqqara by the British Egyptologist James Edward Quibell, in 1910/11. The naked figure of this individual, Djeho, is carved in profile on the lid of his sarcophagus. He has a height of 120 cm and has characteristic clinical features suggesting achondroplasia.


Asunto(s)
Acondroplasia , Enanismo , Masculino , Humanos , Egipto
17.
BMC Public Health ; 23(1): 1557, 2023 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-37587441

RESUMEN

BACKGROUND: It is essential to empower young people to promote reproductive health (RH) and develop effective educational programs to prevent risky behaviors. This study aimed to investigate the factors affecting students' attitudes towards RH based on the ecological model and then design an educational program. METHODS: This cross-sectional study was conducted on 461 female students aged 18-29 in the north of Iran. This study was done in two stages. In the first stage, factors affecting the attitude towards RH including demographic questionnaire, interpersonal communication skills, family communication pattern, depression, stress and anxiety, body self-image, and self-confidence were determined. In the second stage, an educational program was designed based on the most effective factors. Independent t-test, ANOVA, and multiple linear regression were employed using SPSS version 20 software. Also, STATA version 15 software was utilized for statistical modeling to predict the best predictive model of attitude towards RH. RESULTS: 47.7% of students had a good attitude toward RH. The majority of students had problems with interpersonal communication skills (60.7%). Also, 28.5% experienced depression, 35.8% anxiety, and 12.8% stress at different levels. More than a quarter of the students (26.5%) had poor body self-image and 18.7% had Undesirable self-esteem. Interpersonal skills (P = 0.002), family communication pattern (P = 0.004), stress (p = 0.019), anxiety (P = 0.001), and body self-image (P = 0.034) have a significant relationship with the attitude towards RH. The multiple regression showed that the most important effective factor on RH is the dialogue orientation of family communication pattern (P = 0.041), stress (P = 0.002), and anxiety (P = 0.001). CONCLUSION: Stress and anxiety management training and the use of dialogue orientation in the family communication pattern for young female students are recommended based on the scientific model.


Asunto(s)
Salud Reproductiva , Estudiantes , Femenino , Humanos , Adolescente , Irán , Estudios Transversales , Actitud
18.
BMC Anesthesiol ; 23(1): 117, 2023 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-37038110

RESUMEN

BACKGROUND: Hypoglycaemia and hyperglycaemia may develop during anaesthesia and surgery in children and can lead to severe adverse clinical outcomes. No study, as far as we know, has investigated glucose homeostasis in children undergoing surgery in Malawi. The aim of this study was to assess perioperative glucose levels of the children undergoing anaesthesia at Mercy James Centre (MJC) for Paediatric Surgery, Blantyre, Malawi. METHODOLOGY: This was an observational cross-sectional study. We looked at 100 children aged 1 day to 15 years anaesthetised at MJC. Data were analysed using SPSS 28. Student t test and Analysis of the variance (ANOVA) were used to compare means. The level of significance was 5%. RESULTS: Male children represented 68%. The median age was 2.2 years. Sixten percents of patient were underweight. Fasting times were prolonged for 87%. Maintenance IV fluid with 2.5% dextrose was given to 14%. Overall, there was a significant increase of glycaemia from induction of anaesthesia to the end of the procedure. Hypoglycaemia was rare. The mean fasting glycaemia was 99.04 mg/dL ± 1.8, 116.95 mg/dL ± 34.2 at 30 min into the procedure and 127.62 mg/dL ± 46.8 at the end of the procedure. The differences in means were statistically significant (p < 0.001). Prolonged fasting times was associated with lower blood glucose means whereas nutrition status, type of the procedure, addition of dextrose in the fluid, and duration of procedure were associated with higher glycaemia means. CONCLUSION: Glycaemia increases under anaesthesia and surgery. Recommended fasting times, optimising nutritional status, when possible, no dextrose or lower than 2.5% dextrose in IV maintenance fluid are possible strategies to maintain blood sugar homeostasis during paediatric surgery and anaesthesia.


Asunto(s)
Anestesia , Hiperglucemia , Hipoglucemia , Humanos , Masculino , Niño , Preescolar , Malaui , Estudios Transversales , Anestesia/efectos adversos , Glucemia/análisis , Hipoglucemia/inducido químicamente , Hipoglucemia/epidemiología
19.
J Pers ; 91(1): 207-221, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35715894

RESUMEN

INTRODUCTION: James Baldwin (1924-1987) was a prolific African American author and activist whose writing centered primarily on race, sexuality, and religion. Baldwin's lived experiences and breadth of knowledge provided him with a unique perspective of the Black experience in America, a theme he frequently revisited in his work and the impetus for his involvement in the Civil Rights Movement METHOD: This article presents a psychobiographical application of Queering Black Racial Identity Development to conceptualize the life story of James Baldwin. RESULTS: This study explores the life of James Baldwin, highlights his influence as a historical figure and agent of social change, and explores the "why" of his life and behavior. Specifically, his decision to return to the United States during the Civil Rights Movement and possible reasons he avoided politicizing his sexuality in the same way he did his racial identity. CONCLUSION: As an African American, nonheterosexual, male author and Civil Rights activist, Baldwin's intersectional identities played a significant role in his decision to dedicate his life to writing and activism. Limitations of the study are discussed.

20.
Biom J ; 65(5): e2200153, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37068191

RESUMEN

Buckley-James (BJ) model is a typical semiparametric accelerated failure time model, which is closely related to the ordinary least squares method and easy to be constructed. However, traditional BJ model built on linearity assumption only captures simple linear relationships, while it has difficulty in processing nonlinear problems. To overcome this difficulty, in this paper, we develop a novel regression model for right-censored survival data within the learning framework of BJ model, basing on random survival forests (RSF), extreme learning machine (ELM), and L2 boosting algorithm. The proposed method, referred to as ELM-based BJ boosting model, employs RSF for covariates imputation first, then develops a new ensemble of ELMs-ELM-based boosting algorithm for regression by ensemble scheme of L2 boosting, and finally, uses the output function of the proposed ELM-based boosting model to replace the linear combination of covariates in BJ model. Due to fitting the logarithm of survival time with covariates by the nonparametric ELM-based boosting method instead of the least square method, the ELM-based BJ boosting model can capture both linear covariate effects and nonlinear covariate effects. In both simulation studies and real data applications, in terms of concordance index and integrated Brier sore, the proposed ELM-based BJ boosting model can outperform traditional BJ model, two kinds of BJ boosting models proposed by Wang et al., RSF, and Cox proportional hazards model.


Asunto(s)
Algoritmos , Bosques Aleatorios , Modelos de Riesgos Proporcionales , Simulación por Computador , Análisis de los Mínimos Cuadrados
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