383 research outputs found

    Optimal dimensioning model of water distribution systems

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    This study is aimed at developing a pipe-sizing model for a water distribution system. The optimal solution minimises the system’s total cost, which comprises the hydraulic network capital cost, plus the capitalised cost of pumping energy. The developed model, called Lenhsnet, may also be used for economical design when expanding existing hydraulic networks. The methodology developed includes an iterative dynamic calculation process as well as a hydraulic simulation model. The performance of the method is tested against 4 benchmark examples in the literature. The results obtained show the feasibility of this model, presenting it as a viable alternative for water distribution systems. The method is easily used, once it is performed under EPANET2 software interface

    Productive restructuring and the reallocation of work and employment: a survey of the “new” forms of social inequality

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    O propósito do presente artigo consiste em questionar a inevitabilidade dos processos de segmentação e precarização das relações de trabalho e emprego, responsáveis pela inscrição de “novas” formas de desigualdade social que alicerçam o actual modelo de desenvolvimento das economias e sociedades. Visa-se criticar os limites da lógica econômica e financeira, de contornos globais, que configuram um “novo espírito do capitalismo”, ou seja, uma espécie de divinização da ordem natural das coisas. Impõe-se fazer, por isso, um périplo analítico pelas transformações em curso no mercado de trabalho, acompanhado pela vigilância epistemológica que permita enquadrar e relativizar as (di)visões neoliberais e teses tecnodeterministas dominantes. A perspectivação de cenários sobre o futuro do trabalho encerrará este périplo, permitindo-nos alertar para os condicionalismos histórico-temporais, para a urgência de se desocultar o que de ideológico e político existe nas actuais lógicas de racionalização e para os processos de ressimbolização do trabalho e emprego enquanto “experiência social central” na contemporaneidade.The scope of this paper is to question the inevitability of the processes of segmentation and increased precariousness of the relations of labor and employment, which are responsible for the introduction of “new” forms of social inequality that underpin the current model of development of economies and societies. It seeks to criticize the limits of global financial and economic logic, which constitute a “new spirit of capitalism,” namely a kind of reverence for the natural order of things. It is therefore necessary to conduct an analytical survey of the ongoing changes in the labor market, accompanied by epistemological vigilance which makes it possible to see neoliberal (di)visions and dominant technodeterministic theses in context. The enunciation of scenarios on the future of work will conclude this survey and will make it possible to draw attention to both the historical and temporal constraints and to the urgent need to unveil what is ideological and political in the prevailing logic of rationalization and processes to reinstate work and employment as a “central social experience” in contemporary times

    Serum α-Fetoprotein Levels at Time of Recurrence Predict Post-Recurrence Outcomes Following Resection of Hepatocellular Carcinoma

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    Introduction: Although preoperative α-fetoprotein (AFP) has been recognized as an important tumor marker among patients with hepatocellular carcinoma (HCC), the predictive value of AFP levels at the time of recurrence (rAFP) on post-recurrence outcomes has not been well examined. Methods: Patients undergoing curative-intent resection of HCC between 2000 and 2017 were identified using a multi-institutional database. The impact of rAFP on post-recurrence survival, as well as the impact of rAFP relative to the timing and treatment of HCC recurrence were examined. Results: Among 852 patients who underwent resection of HCC, 307 (36.0%) individuals developed a recurrence. The median rAFP level was 8 ng/mL (interquartile range 3-100). Among the 307 patients who developed recurrence, 3-year post-recurrence survival was 48.5%. Patients with rAFP > 10 ng/mL had worse 3-year post-recurrence survival compared with individuals with rAFP 10 vs. 10 vs. 10 ng/mL had a twofold higher hazard of death in the post-recurrence setting (hazard ratio 1.96, 95% confidence interval 1.26-3.04). Conclusion: AFP levels at the time of recurrence following resection of HCC predicted post-recurrence survival independent of the secondary treatment modality used. Evaluating AFP levels at the time of recurrence can help inform post-recurrence risk stratification of patients with recurrent HCC.info:eu-repo/semantics/publishedVersio

    Synergistic Impact of Alpha-Fetoprotein and Tumor Burden on Long-Term Outcomes Following Curative-Intent Resection of Hepatocellular Carcinoma

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    Introduction: The prognostic role of tumor burden score (TBS) relative to pre-operative α -fetoprotein (AFP) levels among patients undergoing curative-intent resection of HCC has not been examined. Methods: Patients who underwent curative-intent resection of HCC between 2000 and 2017 were identified from a multi-institutional database. The impact of TBS on overall survival (OS) and cumulative recurrence relative to serum AFP levels was assessed. Results: Among 898 patients, 233 (25.9%) patients had low TBS, 572 (63.7%) had medium TBS and 93 (10.4%) had high TBS. Both TBS (5-year OS; low TBS: 76.9%, medium TBS: 60.9%, high TBS: 39.1%) and AFP (>400 ng/mL vs. <400 ng/mL: 48.5% vs. 66.1%) were strong predictors of outcomes (both p < 0.001). Lower TBS was associated with better OS among patients with both low (5-year OS, low-medium TBS: 68.0% vs. high TBS: 47.7%, p < 0.001) and high AFP levels (5-year OS, low-medium TBS: 53.7% vs. high TBS: not reached, p < 0.001). Patients with low-medium TBS/high AFP had worse OS compared with individuals with low-medium TBS/low AFP (5-year OS, 53.7% vs. 68.0%, p = 0.003). Similarly, patients with high TBS/high AFP had worse outcomes compared with patients with high TBS/low AFP (5-year OS, not reached vs. 47.7%, p = 0.015). Patients with high TBS/low AFP and low TBS/high AFP had comparable outcomes (5-year OS, 47.7% vs. 53.7%, p = 0.24). The positive predictive value of certain TBS groups relative to the risk of early recurrence and 5-year mortality after HCC resection increased with higher AFP levels. Conclusion: Both TBS and serum AFP were important predictors of prognosis among patients with resectable HCC. Serum AFP and TBS had a synergistic impact on prognosis following HCC resection with higher serum AFP predicting worse outcomes among patients with HCC of a certain TBS class.info:eu-repo/semantics/publishedVersio

    Postoperative Infectious Complications Worsen Long-Term Survival After Curative-Intent Resection for Hepatocellular Carcinoma

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    Background: Postoperative infectious complications may be associated with a worse long-term prognosis for patients undergoing surgery for a malignant indication. The current study aimed to characterize the impact of postoperative infectious complications on long-term oncologic outcomes among patients undergoing resection for hepatocellular carcinoma (HCC). Methods: Patients who underwent curative-intent resection for HCC between 2000 and 2017 were identified from an international multi-institutional database. The relationship between postoperative infectious complications, overall survival (OS), and recurrence-free survival (RFS) was analyzed. Results: Among 734 patients who underwent HCC resection, 269 (36.6%) experienced a postoperative complication (Clavien-Dindo grade 1 or 2 [n = 197, 73.2%] vs grade 3 and 4 [n = 69, 25.7%]). An infectious complication was noted in 81 patients (11.0%) and 188 patients (25.6%) had non-infectious complications. The patients with infectious complications had worse OS (median: infectious complications [46.5 months] vs no complications [106.4 months] [p < 0.001] and non-infectious complications [85.7 months] [p < 0.05]) and RFS (median: infectious complications [22.1 months] vs no complications [45.5 months] [p < 0.05] and non-infectious complications [38.3 months] [p = 0.139]) than the patients who had no complication or non-infectious complications. In the multivariable analysis, infectious complications remained an independent risk factor for OS (hazard ratio [HR], 1.7; p = 0.016) and RFS (HR, 1.6; p = 0.013). Among the patients with infectious complications, patients with non-surgical-site infection (SSI) had even worse OS and RFS than patients with SSI (median OS: 19.5 vs 70.9 months [p = 0.010]; median RFS: 12.8 vs 33.9 months [p = 0.033]). Conclusion: Infectious complications were independently associated with an increased long-term risk of tumor recurrence and death. Patients with non-SSI versus SSI had a particularly worse oncologic outcome.info:eu-repo/semantics/publishedVersio

    Impact of Tumor Burden Score on Conditional Survival after Curative-Intent Resection for Hepatocellular Carcinoma: A Multi-Institutional Analysis

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    Background: The impact of tumor burden score (TBS) on conditional survival (CS) among patients undergoing curative-intent resection of hepatocellular carcinoma (HCC) has not been examined to date. Methods: Patients who underwent liver resection of HCC between 2000 and 2017 were identified from a multi-institutional database. The impact of TBS and other clinicopathologic factors on 3-year conditional survival (CS3) was examined. Results: Among 1,040 patients, 263 (25.3%) patients had low TBS, 668 (64.2%) had medium TBS and 109 (10.5%) had high TBS. TBS was strongly associated with OS; 5-year OS was 39.0% among patients with high TBS compared with 61.1% and 79.4% among patients with medium and low TBS, respectively (p < 0.001). While actuarial survival decreased as time elapsed from resection, CS increased over time irrespective of TBS. The largest differences between 3-year actuarial survival and CS3 were noted among patients with high TBS (5-years postoperatively; CS3: 78.7% vs. 3-year actuarial survival: 30.7%). The effect of adverse clinicopathologic factors including high TBS, poor/undifferentiated tumor grade, microvascular invasion, liver capsule involvement, and positive margins on prognosis decreased over time. Conclusions: CS rates among patients who underwent resection for HCC increased as patients survived additional years, irrespective of TBS. CS estimates can be used to provide important dynamic information relative to the changing survival probability after resection of HCC.info:eu-repo/semantics/publishedVersio

    Multi-Institutional Development and External Validation of a Nomogram for Prediction of Extrahepatic Recurrence After Curative-Intent Resection for Hepatocellular Carcinoma

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    Backgrounds: Extrahepatic recurrence of hepatocellular carcinoma (HCC) after surgical resection is associated with unfavorable prognosis. The objectives of the current study were to identify the risk factors and develop a nomogram for the prediction of extrahepatic recurrence after initial curative surgery. Methods: A total of 635 patients who underwent curative-intent resection for HCC between 2000 and 2017 were identified from an international multi-institutional database. The clinicopathological characteristics, risk factors, and long-term survival of patients with extrahepatic recurrence were analyzed. A nomogram for the prediction of extrahepatic recurrence was established and validated in 144 patients from an external cohort. Results: Among the 635 patients in the derivative cohort, 283 (44.6%) experienced recurrence. Among patients who recurred, 80 (28.3%) patients had extrahepatic ± intrahepatic recurrence, whereas 203 (71.7%) had intrahepatic recurrence only. Extrahepatic recurrence was associated with more advanced initial tumor characteristics, early recurrence, and worse prognosis versus non-extrahepatic recurrence. A nomogram for the prediction of extrahepatic recurrence was developed using the β-coefficients from the identified risk factors, including neutrophil-to-lymphocyte ratio, multiple lesions, tumor size, and microvascular invasion. The nomogram demonstrated good ability to predict extrahepatic recurrence (c-index: training cohort 0.786; validation cohort: 0.845). The calibration plots demonstrated good agreement between estimated and observed extrahepatic recurrence (p = 0.658). Conclusions: An externally validated nomogram was developed with good accuracy to predict extrahepatic recurrence following curative-intent resection of HCC. This nomogram may help identify patients at high risk of extrahepatic recurrence and guide surveillance protocols as well as adjuvant treatments.info:eu-repo/semantics/publishedVersio
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