Pricing routines for vehicle routing with time windows on road networks

Several very effective exact algorithms have been developed for vehicle routing problems with time windows. Unfortunately, most of these algorithms cannot be applied to instances that are defined on road networks, because they implicitly assume that the cheapest path between two customers is equal to the quickest path. Garaix and coauthors proposed to tackle this issue by first storing alternative paths in an auxiliary multi-graph, and then using that multi-graph within a branch-and-price algorithm. We show that, if one works with the original road network rather than the multi-graph, then one can solve the pricing subproblem more quickly, in both theory and practice

Vehicle routing on real road networks

The vehicle routing problem (VRP) has received particular attention, in the field of transportation and logistics. Producing good solutions for the problem is of interest both commercially and theoretically. Reliable solutions to real life applications require an approach based on realistic assumptions that resemble real-world conditions. In that respects, this thesis studies vehicle routing problems on real road networks addressing aspects of the problem that need to be modelled on the original road network graph and aims to provide appropriate modelling techniques for solving them. As a preliminary step, chapter 2 studies the travelling salesman problem (TSP) on real road networks, referred to as the Steiner TSP (STSP) and proposes alternative integer programming formulations for the problem and some other related routing problems. The performances of formulations is examined both theoretically and computationally. Chapter 3 highlights the fact that travel speeds on road networks are correlated and uses a real traffic dataset to explore the structure of this correlation. In conclusion, it is shown that there is still significant spatial correlations between speeds on roads that are up to twenty links apart, in our congested road network. Chapter 4 extends chapter 2 and incorporates the findings of chapter 3 into a modelling framework for VRP. The STSP with correlated costs is defined as a potentially useful variant of VRP that considers the costs in the STSP to be stochastic random variables with correlation. The problem is then formulated as a single-objective problem with eight different integer programming formulations presented. It is then shown how to account for three different correlation structures in each of the formulations. Chapter 5 considers the VRPs with time windows and shows how most of the exact algorithms proposed for them, might not be applicable if the problem is defined on the original road network graph due to the underlying assumption of these algorithms that the cheapest path between a pair of customers is the same as the quickest path. This assumption is not always true on a real road network. Instead some alternative pricing routines are proposed that can solve the problem directly on the original graph

Pricing routines for vehicle routing with time windows on road networks

Several very effective exact algorithms have been developed for vehicle routing problems with time windows. Unfortunately, most of these algorithms cannot be applied to instances that are defined on road networks, because they implicitly assume that the cheapest path between two customers is equal to the quickest path. Garaix and coauthors proposed to tackle this issue by first storing alternative paths in an auxiliary multi-graph, and then using that multi-graph within a branch-and-price algorithm. We show that, if one works with the original road network rather than the multi-graph, then one can solve the pricing subproblem more quickly, in both theory and practice

Acute Myocardial Infarction Due to Dissection of the Coronary Arteries Associated with Premature Atherosclerosis in Late Postpartum: A Case Report of Maternal Death

AbstractIntroduction: Atherosclerotic coronary artery disease is the most common form of heart disease that is associated with high rates of acute myocardial infarction (AMI) and death in young people.Methods: Given the importance of pregnancy and the postpartum period and the fact that AMI is associated with poor maternal outcomes in postpartum, the present study reports acute myocardial infarction due to dissection of the coronary arteries associated with premature atherosclerosis in late postpartum.Results: The case was the maternal death of a 34-year-old woman at 42 days postpartum without any history of underlying diseases or symptoms, whose autopsy report read AMI due to coronary artery dissection associated with atherosclerosis.Conclusions: This report emphasizes the importance of postpartum care and attention to any symptoms witnessed during this period

Postpartum Mental Health and Its Relationship with Mediating Social Determinants of Health in Iran based on the WHO Model: A Systematic Review

Background: Pregnancy is a complex and vulnerable period that causes some challenges including the development of postpartum psychiatric disorders (PPDs) for women. Identifying the factors associated with these disorders can be effective in reducing maternal symptoms and supporting mother, child and family. The aim of this study was to identify the relationship between postpartum mental health and mediating social determinants of health in Iran.Methods: In this systematic review, the Persian and English observational studies in Iran were obtained through advanced search in online databases, such as PubMed, Scopus, EMBASE, SID, Magiran, Psycinfo, and Google Scholar search engine in the period of January 2005 to August 5, 2021 using the following keywords: social determinants, mediating factors, social support, mental health, risk factors, postpartum, Iran, and their English equivalents through Mesh. Articles were selected based on the inclusion and exclusion criteria and quality assessment of articles was performed using the standard Newcastle-Ottawa Scale (NOS).Results: Out of 42 eligible articles (total sample: 39216), 40 articles examined the relationship between postpartum depression and 2 articles studied the relationship of maternal grief with some mediating social determinants. In general, these factors were classified into five categories, including midwifery and pregnancy-related factors, psychosocial conditions, factors related to postpartum status, behavioral factors and material status or conditions, and health care.Conclusion: Mothers' mental health is affected by many underlying factors; Therefore, identifying the risk factors associated with mental disorders in this population based on the model of the WHO (World Health Organization), especially in the mediating area (Material and environmental conditions, Psychosocial, Behavioral factors, Health system) due to the extent of this area is very important

A genetic polymorphism in the CYP1B1 gene in patients with squamous cell carcinoma of the esophagus: an Iranian Mashhad cohort study recruited over 10 years

Background: Esophageal-cancer is the seventh most common-cause of cancer-related-deaths in men. Cytochrome-P450-family-1-subfamily-B-polypeptide-1 (CYP1B1) plays a role in the metabolism of xenobiotics, and is associated with several cancers. Here we investigated the association between a genetic-variant, CYP1B1-rs1056836, with the clinical-characteristics of patients with esophagus-squamous-cell-carcinoma (ESCC). Method: 117-patients with ESCC and 208 healthy-subjects were recruited. DNA was extracted and genotyped. Kaplan-Meier curves were utilized to assess overall and progression-free survival. The relationship between clinicopathological-data, disease-prognosis, and survival, were evaluated with the genotypes. Results: the genotypic frequency for GG, GC, and CC were 58.6%, 29.8%, 11.5% respectively in the healthy subjects and 51.8%, 36.14% and 12% in the ESCC group. An association between the GG genotype and stage of ESCC was found. Conclusion: Our findings suggest a relationship between the CYP1B1-rs1056836 genetic polymorphism and clinical features of ESCC, supporting further studies in larger-populations in different-ethnic groups, taking into account potentially important environmental-factors

The Steiner travelling salesman problem with correlated costs

The Steiner Travelling Salesman Problem (STSP) is a variant of the TSP that is suitable for instances defined on road networks. We consider an extension of the STSP in which the road traversal costs are both stochastic and correlated. This happens, for example, when vehicles are prone to delays due to rush hours, road works or accidents. Following the work of Markowitz on portfolio selection, we model this problem as a bi-objective mean-variance problem. Then, we show how to approximate the efficient frontier via integer programming. We also show how to exploit certain special structures in the correlation matrices. Computational results indicate that our approach is viable for instances with up to 100 nodes. It turns out that minimum variance tours can look rather different from minimum expected cost tours

The use of cranberry for prevention of Urinary tract infection

Background and Aims:Urinary tract infection is a bacterial infection that affects any part of the urinary tract. Antibiotics can be used for prevention of recurrent urinary tract infection,and due to the adverse effects of chemical medicines including allergen effects, resistance creation to bacteria and toxicity cases, herbal treatment have been noticed alternatively. This study aimed to identify effective herbal drugs on preventing urinary tract infection. Materials and Methods:Databases such as Ovid, Medline, Scopus, Science direct and Inter science were searched using keywords such as complementary therapy, herbal medicine, alternative medicine and urinary tract infection from 1994 to 2012. Results:Studies have shown that herbal products particularl

Effect of problem-solving therapy and relaxation on the severity of postpartum depressive symptoms: A randomized controlled trial

Background: Postpartum depression with high prevalence and unpleasant complications needs to be identified and treated. Objective: This study aimed to compare the effect of problem-solving therapy (PST) and relaxation on the severity of postpartum depressive symptoms. Methods: This randomized controlled trial was performed in health-care centers of Mashhad city, Iran, in women on the 3rd postpartum week. A total of 120 women were selected conveniently and randomly assigned to three groups (i.e., PST, relaxation, and control groups). The women completed Edinburgh Depression Scale and Beck Depression Inventory (BDI). Problem-solving skills were educated during six weekly sessions. Progressive muscle relaxation exercises and guided imagery were performed daily and once a week during 6 weeks, respectively. In the control group, women received usual postpartum care. All groups completed a daily checklist for recording depression symptoms. The three groups completed the BDI once again a week after the end of the intervention. Data analysis was conducted using Chi-square, paired t-test, analysis of variance (ANOVA), and repeated measures ANOVA. Results: The mean difference of severity of depressive symptoms was significantly different between the three groups at 9 weeks after delivery (-14.86 ± 6.15 in PST group,-10.71 ± 5.23 in relaxation group, and -4.72 ± 4.51 in the control group, P Conclusion: Both PST and relaxation can reduce the severity of depressive symptoms. However, the effects of PST were more than those of relaxation