166 research outputs found
Cosmological implications of dwarf spheroidal chemical evolution
The chemical properties of dwarf spheroidals in the local group are shown to
be inconsistent with star formation being truncated after the reionization
epoch (z~8). Enhanced levels of [Ba/Y] in stars in dwarf spheroidals like
Sculptor indicate strong s-process production from low-mass stars whose
lifetimes are comparable with the duration of the pre-reionization epoch. The
chemical evolution of Sculptor is followed using a model with SNeII and SNeIa
feedback and mass- and metallicity-dependent nucleosynthetic yields for
elements from H to Pb. We are unable to reproduce the Ba/Y ratio unless stars
formed over an interval long enough for the low-mass stars to pollute the
interstellar medium with s-elements. This robust result challenges the
suggestion that most of the local group dwarf spheroidals are fossils of
reionization and supports the case for large initial dark matter halos.Comment: 7 pages, 4 figures. Accepted for publication in ApJ. Minor changes
following referee repor
Influência da largura da faixa de trabalho na operação de corte com feller-buncher
A produtividade operacional do feller-buncher pode ser influenciada por diversos fatores, tais como: tipo de máquina, volume médio individual, espécie, operador, declividade, tipo de solo, eito de trabalho, diâmetro a altura do peito, entre outros. A hipótese abordada neste trabalho foi se o eito de trabalho (3 e 4 linhas) poderia influenciar na produtividade da máquina. Diante disso, o objetivo foi a avaliação técnica de um feller-buncher em uma floresta de Eucalyptus platyphilla, realizando o corte em um eito operacional composto por três e quatro linhas de plantio. Os dados foram obtidos por meio de um estudo de tempos e métodos, realizado pelo método do tempo contínuo considerando para a análise dois tratamentos (nomeados como T1 e T2). Entre os tratamentos avaliados, para um eito de trabalho com três linhas (9 metros) a produtividade foi de 154,34 m³ h-1 e para o eito de trabalho com quatro linhas (12 metros) foi de 135,10 m³ h-1. Independentemente do eito de trabalho o elemento cortar foi a que mais consumiu tempo por ciclo. Conclui-se que o eito de trabalho influenciou na produtividade do feller-buncher na operação de corte de árvores
Inhibition of CCL3 abrogated precursor cell fusion and bone erosions in human osteoclast cultures and murine collagen-induced arthritis
Objective Macrophage inflammatory protein 1-alpha (CCL3) is a chemokine that regulates macrophage trafficking to the inflamed joint. The agonistic effect of CCL3 on osteolytic lesions in patients with multiple myeloma is recognized; however, its role in skeletal damage during inflammatory arthritis has not been established. The aim of the study was to explore the role of osteoclast-associated CCL3 upon bone resorption, and to test its pharmacological blockade for protecting against bone pathology during inflammatory arthritis. Methods CCL3 production was studied during osteoclast differentiation from osteoclast precursor cells: human CD14-positive mononuclear cells. Mice with CIA were treated with an anti-CCL3 antibody. The effect of CCL3 blockade through mAb was studied through osteoclast number, cytokine production and bone resorption on ivory disks, and in vivo through CIA progression (clinical score, paw diameter, synovial inflammation and bone damage). Results Over time, CCL3 increased in parallel with the number of osteoclasts in culture. Anti-CCL3 treatment achieved a concentration-dependent inhibition of osteoclast fusion and reduced pit formation on ivory disks (P ⩽ 0.05). In CIA, anti-CCL3 treatment reduced joint damage and significantly decreased multinucleated tartrate-resistant acid phosphatase-positive osteoclasts and erosions in the wrists (P < 0.05) and elbows (P < 0.05), while also reducing joint erosions in the hind (P < 0.01) and fore paws (P < 0.01) as confirmed by X-ray. Conclusion Inhibition of osteoclast-associated CCL3 reduced osteoclast formation and function whilst attenuating arthritis-associated bone loss and controlling development of erosion in murine joints, thus uncoupling bone damage from inflammation. Our findings may help future innovations for the diagnosis and treatment of inflammatory arthritis
Thyroid ultrasound: state of the art. part 2 - focal thyroid lesions.
Abstract
Accurate differentiation of focal thyroid nodules (FTL) and thyroid abnormalities is pivotal for proper diagnostic and therapeutic work-up. In these two part articles, the role of ultrasound techniques in the characterization of FTL and evaluation of diffuse thyroid diseases is described to expand on the recently published World Federation in Ultrasound and Medicine (WFUMB) thyroid elastography guidelines and review how this guideline fits into a complete thyroid ultrasound exam
Thyroid ultrasound: State of the art part 1 - Thyroid ultrasound reporting and diffuse thyroid diseases
Accurate differentiation of focal thyroid nodules (FTL) and thyroid abnormalities is pivotal for proper diagnostic and therapeutic work-up. In these two part articles, the role of ultrasound techniques in the characterization of FTL and evaluation of diffuse thyroid diseases is described to expand on the recently published World Federation in Ultrasound and Medicine (WFUMB) thyroid elastography guidelines and review how this guideline fits into a complete thyroid ultrasound exam
Association of pulmonary function and functional capacity with invasive mechanical ventilation time after coronary artery bypass grafting
Introdução: A cirurgia de revascularização do miocárdio (CRM) é realizada para diminuir os sintomas característicos da doença arterial coronariana (DAC) e após esse procedimento os pacientes necessitam de ventilação mecânica invasiva (VMI). Um tempo prolongado de VMI resulta no aumento de complicações pulmonares, mortalidade e prolonga o tempo de internação hospitalar. Objetivo: Verificar a associação entre a função pulmonar e a capacidade funcional pré-operatória com o tempo de VMI após CRM. Casuística e Métodos: Estudo de coorte prospectivo realizado entre 2011 e 2015 com inclusão de 40 indivíduos. Foram avaliadas a capacidade funcional e função pulmonar no pré-operatório da CRM, além do tempo de VMI no momento após o procedimento cirúrgico. Resultados: As variáveis da função pulmonar apresentaram correlação inversa com o tempo de VMI pós CRM, capacidade vital forçada (CVF) (r = -0,51; p = 0,001); o volume expiratório forçado no 1º segundo (VEF1) (r = -0,49; p = 0,001), o pico de fluxo expiratório (PFE) (r = -0,42; p = 0,008) e a capacidade vital inspiratória (CVin) (r = -0,51; p = 0,001). A mesma correlação não foi observada entre a capacidade funcional (r = -0,22; p = 0,166) e o tempo de VMI pós CRM. Conclusão: Os pacientes que apresentaram melhor função pulmonar no pré-operatório de CRM, necessitaram um menor tempo de VMI após essa cirurgia. O mesmo não foi observado em relação a capacidade funcional.Introduction: The coronary artery bypass grafting (CABG) is widely utilized to decrease the symptoms of coronary artery disease. After this surgery the patients will need mechanical ventilation. Prolonged mechanical ventilation results in higher rates of pulmonary complications and mortality, as well as higher hospital length of stay. Objective: To evaluate the association between pulmonary function, functional capacity, and the duration of invasive mechanical ventilation after CABG. Patients and Methods: The prospective cohort study was carried out during 2011 and 2015. In total, 40 patients undergoing CABG were evaluated for preoperative pulmonary function and functional capacity. Results: Preoperative pulmonary function was found to be inversely proportional to duration of invasive mechanical ventilation after CABG, forced vital capacity (FVC) (r = -0,5; p = 0,001), forced expiratory volume in 1 second (FEV1) (r = -0,49; p = 0,001), peak expiratory flow (PEF) (r = -0,42; p = 0,008), inspiratory vital capacity (IVC) (r = -0,51; p = 0,001). However, there was no correlation between functional capacity (r = -0,22; p = 0,166) and duration of invasive mechanical ventilation after CABG. Conclusion: The patients whose pulmonary function were significantly higher remained less time under ventilation than the patients with poorer pulmonary function. However, there was no relation between functional capacity and duration of invasive mechanical ventilation in these patients
Qualidade físico-hídrica de monolitos de solo de volumes variados coletados em solos de diferentes granulometries/Physical-hydric quality of soil monoliths of varying volumes collected in soils of different particle sizes
Atualmente a forma utilizada para realização de experimentos na área agrícola representa em sua grande maioria o sistema convencional de cultivo, onde o solo coletado é desagregado e, posteriormente, colocado em recipientes para condução em casas de vegetação. Visando facilitar a coleta de amostras indeformadas e aprimorar os estudos de solos em condição natural objetivou-se desenvolver um equipamento capaz de coletar monolitos de solo no formato cilíndrico e cônico de diversos diâmetros com profundidade máxima de 0,27 m. Seu princípio de funcionamento baseia-se no princípio da usinagem, ou seja, o solo vai sendo desbastado mecanicamente pela ação da aresta de corte da ferramenta, reduzindo dessa forma a compactação pela fricção do solo na lateral do cilindro e o cisalhamento provocado pelos métodos tradicionais. As variáveis analisadas foram: umidade do solo por ocasião da coleta, umidade na capacidade de campo, qualidade dos monolitos em diferentes solos. O equipamento mostrou-se adequado para a coleta de monolitos indeformados para todos os solos avaliados, mantendo a estrutura natural do solo
Botanical (morphological, micrographic), chemical and pharmacological characteristics of Pfaffia species (Amaranthaceae) native to South Brazil
Alguns parâmetros são apresentados para o controle de qualidade de raízes de Pfaffia glomerata e Pfaffia paniculata, utilizando suas características botânicas e químicas. Realizou-se, também, um screening farmacológico de P. glomerata direcionado às atividades relacionadas com seu uso como "tônico". O extrato etanólico das raízes de P. glomerata não apresentou atividade antiviral, antiproliferativa, antifúngica ou atividade inibitória de monoaminoxidases. A avaliação da citotoxicidade determinou que a CI50 é >; 2.000 µg/mL. As principais características morfológicas e micrográficas das raízes de P. glomerata e P. paniculata descritas permitem auxiliar na sua identificação segura.Some parameters for the quality control of P. glomerata and P. paniculata roots using their botanical and chemical characteristics are presented. It was also carried out an in vitro pharmacological screening to evaluate some biological properties of P. glomerata that could be related to its popular use as "tonic". Relating to biological assays, ethanolic extract from P. glomerata roots did not present antiviral, antiproliferative, antifungal or MAO inhibitory activities. The cytotoxicity evaluation of P. glomerata determined that IC50 is >;2,000 µg/mL. The main morphological and micrographic characteristics of P. glomerata and P. paniculata roots are described in this paper in order to aid in their unequivocal identification
Shaping care home COVID-19 testing policy: a protocol for a pragmatic cluster randomised controlled trial of asymptomatic testing compared with standard care in care home staff (VIVALDI-CT)
INTRODUCTION: Care home residents have experienced significant morbidity, mortality and disruption following outbreaks of SARS-CoV-2. Regular SARS-CoV-2 testing of care home staff was introduced to reduce transmission of infection, but it is unclear whether this remains beneficial. This trial aims to investigate whether use of regular asymptomatic staff testing, alongside funding to reimburse sick pay for those who test positive and meet costs of employing agency staff, is a feasible and effective strategy to reduce COVID-19 impact in care homes. METHODS AND ANALYSIS: The VIVALDI-Clinical Trial is a multicentre, open-label, cluster randomised controlled, phase III/IV superiority trial in up to 280 residential and/or nursing homes in England providing care to adults aged >65 years. All regular and agency staff will be enrolled, excepting those who opt out. Homes will be randomised to the intervention arm (twice weekly asymptomatic staff testing for SARS-CoV-2) or the control arm (current national testing guidance). Staff who test positive for SARS-CoV-2 will self-isolate and receive sick pay. Care providers will be reimbursed for costs associated with employing temporary staff to backfill for absence arising directly from the trial.The trial will be delivered by a multidisciplinary research team through a series of five work packages.The primary outcome is the incidence of COVID-19-related hospital admissions in residents. Secondary outcomes include the number and duration of outbreaks and home closures. Health economic and modelling analyses will investigate the cost-effectiveness and cost consequences of the testing intervention. A process evaluation using qualitative interviews will be conducted to understand intervention roll out and identify areas for optimisation to inform future intervention scale-up, should the testing approach prove effective and cost-effective. Stakeholder engagement will be undertaken to enable the sector to plan for results and their implications and to coproduce recommendations on the use of testing for policy-makers. ETHICS AND DISSEMINATION: The study has been approved by the London-Bromley Research Ethics Committee (reference number 22/LO/0846) and the Health Research Authority (22/CAG/0165). The results of the trial will be disseminated regardless of the direction of effect. The publication of the results will comply with a trial-specific publication policy and will include submission to open access journals. A lay summary of the results will also be produced to disseminate the results to participants. TRIAL REGISTRATION NUMBER: ISRCTN13296529
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