141 research outputs found

    Generalized Forward-Backward Splitting

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    This paper introduces the generalized forward-backward splitting algorithm for minimizing convex functions of the form F+i=1nGiF + \sum_{i=1}^n G_i, where FF has a Lipschitz-continuous gradient and the GiG_i's are simple in the sense that their Moreau proximity operators are easy to compute. While the forward-backward algorithm cannot deal with more than n=1n = 1 non-smooth function, our method generalizes it to the case of arbitrary nn. Our method makes an explicit use of the regularity of FF in the forward step, and the proximity operators of the GiG_i's are applied in parallel in the backward step. This allows the generalized forward backward to efficiently address an important class of convex problems. We prove its convergence in infinite dimension, and its robustness to errors on the computation of the proximity operators and of the gradient of FF. Examples on inverse problems in imaging demonstrate the advantage of the proposed methods in comparison to other splitting algorithms.Comment: 24 pages, 4 figure

    Spectra of products and numerical ranges

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33367/1/0000765.pd

    Cementless ceramic-on-ceramic total hip replacement in children and adolescents

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    Background: total hip replacement (THR) is a rare surgical option in children and adolescents with disabling hip diseases. The aim of this study is to report results from a retrospective cohort of patients aged 18 years or less who underwent cementless Ceramic-on-Ceramic (CoC) THR at a single institution, investigating clinical and radiographic outcomes, survival rates, and reasons for revision of the implants. Materials and methods: we queried the Registry of Prosthetic Orthopedic Implants (RIPO) to identify all children and adolescents undergoing THR between 2000 and 2019 at a single Institution. Inclusion criteria were patients undergoing cementless CoC THR, aged less than 18 years at surgery, followed for at least 2 years. Sixty-eight patients (74 hips) matched all the inclusion criteria and were enrolled in the study. We assessed the clinical and radiographic outcomes, the rate of complications, the survival rate, and reasons for revision of the implants. Results: The mean follow-up was 6.6 ± 4.4 years (range 2–20). The most frequent reason for THR was post-traumatic or chemotherapy-induced avascular necrosis (38%). The overall survival rate of the cohort was 97.6% (95% CI: 84.9–99.7%) at 5 years of follow-up, 94.4% (95% CI: 79.8–98.6%) at 10 years and 15 years of follow-up. Two THR in two patients (2.7%) required revision. With the numbers available, Cox regression analysis could not detect any significant interaction between preoperative or intraoperative variables and implant survivorship (p-value 0.242 to 0.989).” The average HOOS was 85 ± 14.3 (range 30.6–100). Overall, 23 patients (48%) reported excellent HOOS scores (>90 points), 21 patients (44%) reported acceptable HOOS scores (60–90 points) while 4 patients (8%) reported poor outcomes (<60 points). Twenty-one patients (43%) were regularly involved into moderate-to high-intensity sport activities (UCLA ≥ 6). Conclusions: Cementless CoC THR is a successful procedure in children and teenagers, having demonstrated high implant survivorship and low rates of complications and failure. A meticulous preoperative planning and implant selection is mandatory, to avoid implant malposition, which is the main reason of failure and revision in these cases. Further studies are needed to assess the impact of the THR on the psychosocial wellbeing of teenagers, as well as risks and benefits and cost-effectiveness in comparison to the hip preserving surgical procedures

    The PROVENT-C19 registry: A study protocol for international multicenter SIAARTI registry on the use of prone positioning in mechanically ventilated patients with COVID-19 ARDS

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    Background The worldwide use of prone position (PP) for invasively ventilated patients with COVID-19 is progressively increasing from the first pandemic wave in everyday clinical practice. Among the suggested treatments for the management of ARDS patients, PP was recommended in the Surviving Sepsis Campaign COVID-19 guidelines as an adjuvant therapy for improving ventilation. In patients with severe classical ARDS, some authors reported that early application of prolonged PP sessions significantly decreases 28-day and 90-day mortality. Methods and analysis Since January 2021, the COVID19 Veneto ICU Network research group has developed and implemented nationally and internationally the "PROVENT-C19 Registry", endorsed by the Italian Society of Anesthesia Analgesia Resuscitation and Intensive Care. . .'(SIAARTI). The PROVENT-C19 Registry wishes to describe 1. The real clinical practice on the use of PP in COVID-19 patients during the pandemic at a National and International level; and 2. Potential baseline and clinical characteristics that identify subpopulations of invasively ventilated patients with COVID-19 that may improve daily from PP therapy. This web-based registry will provide relevant information on how the database research tools may improve our daily clinical practice. Conclusions This multicenter, prospective registry is the first to identify and characterize the role of PP on clinical outcome in COVID-19 patients. In recent years, data emerging from large registries have been increasingly used to provide real-world evidence on the effectiveness, quality, and safety of a clinical intervention. Indeed observation-based registries could be effective tools aimed at identifying specific clusters of patients within a large study population with widely heterogeneous clinical characteristics. Copyright

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    Catálogo de autoridades da Rede BIM (DPHDM): Estudo de caso no tratamento de registros de pontos de acesso

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    Identificar possíveis problemas na alimentação da base de autoridades de assuntos da Rede BIM através da utilização do software Pergamum, e contribuir para padronização de seus pontos de acesso. A partir da revisão da literatura proposta, considera a importância da recuperação da informação para sua disseminação e ainda faz um breve levantamento dos padrões internacionais utilizados para esse fim. A metodologia utilizada envolveu a análise da base, limitada à letra “c” do alfabeto, e se propôs a detectar possíveis inconsistências existentes. Os principais problemas encontrados foram: falhas de grafia, falhas de entrada de cabeçalhos e duplicidade de assuntos. Os resultados práticos para a Rede BIM são: agilização dos serviços de catalogação e referência da Rede BIM, maior controle bibliográfico e facilidade na recuperação de itens nas pesquisas dos usuários. O Estudo de caso se propõe a contribuir com esclarecimentos quanto a equívocos cometidos, de forma a auxiliar na padronização e documentação do processo de alimentação da base de autoridades de assuntos pelos bibliotecários das 45 organizações militares, possibilitando benefícios aos serviços de catalogação e referência e finalmente, propiciando um atendimento mais prático e ágil ao usuário da Rede BIM

    Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

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    Contains fulltext : 172380.pdf (publisher's version ) (Open Access
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