The Complexity of Mean Flow Time Scheduling Problems with Release Times

We study the problem of preemptive scheduling n jobs with given release times on m identical parallel machines. The objective is to minimize the average flow time. We show that when all jobs have equal processing times then the problem can be solved in polynomial time using linear programming. Our algorithm can also be applied to the open-shop problem with release times and unit processing times. For the general case (when processing times are arbitrary), we show that the problem is unary NP-hard.Comment: Subsumes and replaces cs.DS/0412094 and "Complexity of mean flow time scheduling problems with release dates" by P.B, S.

Stated preferences

Numerous articles dealing with stated preferences are published every year in journals related to agriculture, environment or health. Hence, it is not easy to find all the relevant articles when performing a benefit transfer, a meta-analysis or a review of literature. Also, it is not easy to identify trends or common practices in these fields regarding the elicitation method. We have constructed and made available a unique database comprising 1,657 choice experiment and/or contingent valuation articles published in journals related to agriculture, environment or health between 2004 and 2016. We show that the number of choice experiment studies keeps increasing and the single-bounded dichotomous choice format is the most employed question format in contingent valuation studies. We also consider the new nomenclature proposed by Carson and Louviere (2011) and we show that the “discrete choice experiment” is more popular than the “matching method”, especially in journals related to agriculture

Influence of cirrhosis on outcomes of patients with advanced intrahepatic cholangiocarcinoma receiving chemotherapy

International audienceBackground: Cirrhosis is a risk factor for intrahepatic cholangiocarcinoma (iCC). However, its exact prevalence is uncertain and its impact on the management of advanced disease is not established.Methods: Retrospective analysis of patients treated with systemic chemotherapy for advanced iCC in the 1st-line setting at 2 tertiary cancer referral centres. Cirrhosis was diagnosed based on at least one element prior to any treatment: pathological diagnosis, baseline platelets <150 × 109/L, portal hypertension and/or dysmorphic liver on imaging.Results: In the cohort of patients (n = 287), 82 (28.6%) had cirrhosis (45 based on pathological diagnosis). Patients with cirrhosis experienced more grade 3/4 haematologic toxicity (44% vs 22%, respectively, P = 0.001), and more grade 3/4 non-haematologic toxicity (34% vs 14%, respectively, P = 0.001) than those without. The overall survival (OS) was significantly shorter in patients with cirrhosis: median 9.1 vs 13.1 months for those without (HR = 1.56 [95% CI: 1.19-2.05]); P = 0.002), confirmed on multivariable analysis (HR = 1.48 [95% CI: 1.04-2.60]; P = 0.028).Conclusion: Cirrhosis was relatively common in patients with advanced iCC and was associated with increased chemotherapy-induced toxicity and shorter OS. Formal assessment and consideration of cirrhosis in therapeutic management is recommended

A linear programming-based method for job shop scheduling

We present a decomposition heuristic for a large class of job shop scheduling problems. This heuristic utilizes information from the linear programming formulation of the associated optimal timing problem to solve subproblems, can be used for any objective function whose associated optimal timing problem can be expressed as a linear program (LP), and is particularly effective for objectives that include a component that is a function of individual operation completion times. Using the proposed heuristic framework, we address job shop scheduling problems with a variety of objectives where intermediate holding costs need to be explicitly considered. In computational testing, we demonstrate the performance of our proposed solution approach

Fluropyrimidine single agent or doublet chemotherapy as second line treatment in advanced biliary tract cancer

Fluoropyrimidine (FP) plus platinum chemotherapy has been recently established as a second-line (L2) preferred option in advanced biliary tract cancer (aBTC) (ABC-06 phase III trial). However, the overall survival (OS) benefit was limited and comparison with FP monotherapy was not available. Our aim was to assess the OS of patients treated with a FP monotherapy compared to a doublet with irinotecan or platinum in L2. We performed a retrospective analysis of two large multicenter prospective cohorts: a French cohort (28 centers) and an Italian cohort (9 centers). All consecutive patients with aBTC receiving FP-based L2 after gemcitabine plus cisplatin/gemcitabine plus oxaliplatin L1 between 2003 and 2016 were included. A subgroup analysis according to performance status (PS) and an exploratory analysis according to platinum sensitivity in L1 were planned. In the French cohort (n = 351), no significant OS difference was observed between the FP monotherapy and doublet groups (median OS: 5.6 vs 6.8 months, P =.65). Stratification on Eastern Cooperative Oncology Group (ECOG) PS showed similar results in PS 0-1 and 2. Median OS was not different between FP monotherapy, platinum- and irinotecan-based doublets (5.6 vs 7.1 vs 6.7 months, P =.68). Similar findings were observed in the Italian cohort (n = 174) and in the sensitivity analysis in pooled cohorts (n = 525). No L2 regimen seemed superior over others in the platinum resistant/refractory or sensitive subgroups. Our results suggest that FP monotherapy is as active as FP doublets in aBTC in L2, regardless of the patient PS and country, and could be a therapeutic option in this setting

To tax or to ban? A discrete choice experiment to elicit public preferences for phasing out glyphosate use in agriculture

In 2023, the European Union will vote on the reauthorization of glyphosate use, renewed in 2017 despite concern on impacts on the environment and public health. A ban is supported by several Member States but rejected by most farmers. What are citizens’ preferences to phase out glyphosate? To assess whether taxation could be an alternative to a ban, we conducted a discrete choice experiment in five European countries. Our results reveal that the general public is strongly willing to pay for a reduction in glyphosate use. However, while 75.5% of respondents stated to support a ban in the pre-experimental survey, experimental results reveal that in 73.35% of cases, earmarked taxation schemes are preferred when they lead to a strong reduction in glyphosate use for an increase in food price lower than that induced by a ban. When glyphosate reduction is balanced against its costs, a tax may be preferred

A DFO technique to calibrate queueing models

A crucial step in the modeling of a system is to determine the values of the parameters to use in the model. In this paper we assume that we have a set of measurements collected from an operational system, and that an appropriate model of the system (e.g., based on queueing theory) has been developed. Not infrequently proper values for certain parameters of this model may be difficult to estimate from available data (because the corresponding parameters have unclear physical meaning or because they cannot be directly obtained from available measurements, etc.). Hence, we need a technique to determine the missing parameter values, i.e., to calibrate the model. As an alternative to unscalable "brute force" technique, we propose to view model calibration as a nonlinear optimization problem with constraints. The resulting method is conceptually simple and easy to implement. Our contribution is twofold. First, we propose improved definitions of the "objective function" to quantify the "distance" between performance indices produced by the model and the values obtained from measurements. Second, we develop a customized derivative-free optimization (DFO) technique whose original feature is the ability to allow temporary constraint violations. This technique allows us to solve this optimization problem accurately, thereby providing the "right" parameter values. We illustrate our method using two simple real-life case studies

Hepatocellular carcinoma in elderly patients: challenges and solutions

Angélique Brunot, Samuel Le Sourd, Marc Pracht, Julien Edeline Department of Medical Oncology, Centre Eugene Marquis, Rennes, FranceAbstract: Hepatocellular carcinoma (HCC) is the second most common cause of death by cancer in the world. Due to the delayed HCC development in hepatitis C carriers and nonalcoholic fatty liver disease, the incidence of HCC in the elderly is increasing and is becoming a global health issue. Elderly patients with HCC should be assessed through proper oncologic approach, namely, screening tools for frailty (Geriatric-8 or Vulnerable Elders Survey-13) and comprehensive geriatric assessment. This review of the literature supports the same treatment options for elderly patients as for younger patients, in elderly patients selected as fit following proper oncogeriatric assessment. Unfit patients should be managed through a multidisciplinary team involving both oncological and geriatrician professionals. Specific studies and recommendations for HCC in the elderly should be encouraged.Keywords: liver cancer, treatment, surgery, geriatric evaluation, sorafeni