A joint replenishment competitive location problem

Competitive Location Models seek the positions which maximize the market captured by an entrant firm from previously positioned competitors. Nevertheless, strategic location decisions may have a significant impact on inventory and shipment costs in the future affecting the firm’s competitive advantages. In this work we describe a model for the joint replenishment competitive location problem which considers both market capture and replenishment costs in order to choose the firm’s locations. We also present an metaherusitic method to solve it based on the Viswanathan’s (1996) algorithm to solve the Replenishment Problem and an Iterative Local Search Procedure to solve the Location Problem.N/

A regret model applied to the maximum coverage location problem with queue discipline

This article discusses issues related to the location and allocation problems where is intended to demonstrate, through the random number generation, the influence of congestion of such systems in the final solutions. It is presented an algorithm that, in addition to the GRASP, incorporates the Regret with the pminmax method to evaluate the heuristic solution obtained in regard to its robustness for different scenarios. To the well know Maximum Coverage Location Problem from Church and Revelle [1] an alternative perspective is added in which the choice behavior of the server does not only depend on the elapsed time from the demand point looking to the center, but also includes the waiting time for service conditioned by a waiting queue.N/

A regret model applied to the facility location problem with limited capacity facilities

This article addresses issues related to location and allocation problems. Herein, we intend to demonstrate the influence of congestion, through the random number generation, of such systems in final solutions. An algorithm is presented which, in addition to the GRASP, incorporates the Regret with the pminmax method to evaluate the heuristic solution obtained with regard to its robustness for different scenarios. Taking as our point of departure the Facility Location Problem proposed by Balinski [27], an alternative perspective is added associating regret values to particular solutions.N/

A regret model applied to the maximum capture location problem

This article addresses issues related to location and allocation problems. Herein, we intend to demonstrate the influence of congestion, through the random number generation, of such systems in final solutions. An algorithm is presented which, in addition to the GRASP, incorporates the Regret with the pminmax method to evaluate the heuristic solution obtained with regard to its robustness for different scenarios. Taking as our point of departure the Maximum Capture Location Problem proposed by Church and Revelle [1, 26], an alternative perspective is added in which the choice behavior of the server does not depend only on the elapsed time from the demand point looking to the center, but includes also the service waiting time.N/

Modelos regret aplicados a problemas de localização

Tese de Doutoramento em Ciências Económicas e Empresariais (Planeamento Económico e Métodos Quantitativos).Dada a importância da prestação de serviços face à procura existente e aos custos inerentes à sua configuração, os problemas de localização são de suma importância quer no quotidiano quer no meio científico. Na tentativa de captar as particularidades desses sistemas e fazer uma aproximação à realidade, os modelos de localização tornaram-se de tal forma complexos que os resultados por enumeração completa se tornam de difícil obtenção fruto essencialmente do crescimento exponencial do tempo de computação. O presente trabalho apresenta um algoritmo que, além do conhecido GRASP, incorpora o método p-minmax Regret com o objetivo de avaliar a solução heurística obtida no que concerne a sua robustez para diferentes cenários. A utilização desses processos vem na linha de pesquisas anteriores e visa a sua integração com o intuito de explorar novas metodologias que melhorem ou melhor se adaptem às circunstâncias dos casos estudados. Fazendo variar os limites em termos de tempos de espera e de distância máxima percorrida, limites de capacidades de processamento da procura e dimensão das redes, é possível verificar mudanças significativas nas soluções finais. Os problemas em estudo são o bem conhecido Problema de Localização com Cobertura Máxima de ReVelle e um modelo alternativo no qual o comportamento de escolha do servidor não depende apenas do tempo percorrido do nó ao centro, mas também inclui o tempo de espera pelo serviço. Foram também abordados o Problema de Localização de Captura Máxima, do mesmo autor, e o Problema de Localização de Infraestruturas com Capacidades Limitadas com base no problema estudado originalmente por Balinski. Os modelos testados e os seus vários exemplos foram obtidos com recurso à geração numérica aleatória. Em muitos casos, evidenciam-se resultados distintos mas existem outros onde a formulação proposta não produz diferenças significativas nos resultados. De uma forma geral, nos sistemas mais “apertados”, ou seja, onde o limite de distância seja mais pequeno, o número de centros de serviço sejam em menor número ou as capacidades de processamento das infraestruturas menores, as decisões de localização são mais sensíveis aos parâmetros pré-definidos para o modelo. Em conclusão, tendo-se simulado as populações e as respetivas frequências de procura, com este trabalho consegue-se evidenciar a suma importância, tal como na vida real, de considerar o congestionamento dos sistemas nas suas várias vertentes como um fator determinante nas decisões de localização e afetação.ABSTRACT: Given the importance of service delivery compared to existing demand and the costs associated with setting, location problems are of paramount importance both for daily issues and for the scientific community. In an attempt to capture the particularities of these systems and make an approximation to reality, the location models have become so complex that complete enumeration results become difficult to obtain essentially as a result of the exponential growth of computing time. This paper presents an algorithm that, besides the known GRASP, incorporates the p-minmax Regret method in order to evaluate the heuristic solution obtained with respect to its robustness through different scenarios. The use of these processes is in line with previous research and aims at their integration in order to explore new methodologies that improve or best suit the circumstances of the cases studied. By varying the limits in terms of waiting times and maximum distance travelled, maximum demand processing capabilities and size of the network, you can see significant changes in the final solutions. The problems under study are the well-known Location Problem with Maximum Coverage of ReVelle and an alternative model in which the server’s choice behavior not only depends on the elapsed time from the node to the center, but also includes the waiting time for the service. We also discussed the Maximum Capture Location Problem, by the same author, and the Limited Capacity Infrastructure Location Problem based on the problem originally studied by Balinski. The models and their various examples were obtained using the random number generation. In many cases, different results are apparent but there are others in which the formulation proposed produces no significant differences in results. Generally, in systems more "tight", that is, where the distance limit is smaller, the service centers are fewer in number or infrastructure’s processing capabilities smaller, location decisions are more sensitive to preset parameters for the model. In conclusion, having been simulated populations and the respective frequencies of demand, this work manages to highlight the utmost importance, as in real life, considering the congestion of the systems in its various aspects as a determining factor in location and affectation decisions

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

An fMRI study of cognitive regulation of reward processing in generalized anxiety disorder (GAD)

Background: Cognitive regulation can affect the process of decision making. Generalized anxiety disorder (GAD) patients seem to have an impairment in cognitive regulation of reward processing concerning food stimuli. This study aims to explore the impact of GAD in cognitive regulation of food-related rewards. Methods: GAD patients (n=11) and healthy controls (n=15) performed a cognitive regulation craving task with food images while undergoing a functional magnetic resonance imaging (fMRI) acquisition. Between-group differences in functional connectivity were measured using dorsolateral prefrontal cortex (dlPFC) and ventromedial prefrontal cortex (vmPFC) seeds during cognitive regulation. Results: During cognitive regulation, there was a significant interaction for functional connectivity between the right dlPFC and bilateral vmPFC with the thalamus. GAD patients had lower functional connectivity for cognitive regulation conditions (distance and indulge) than for the non-regulated condition in these clusters, while control participants presented the opposite pattern. GAD group presented fixed food valuation scores after cognitive regulation. Conclusions: GAD participants showed inflexibility while valuating food images, that could be produced by cognitive regulation deficits underpinned by functional connectivity alterations between prefrontal regions and the thalamus. These results show cognitive inflexibility and difficulty in the modulation of cognitive responses during decision making in GAD patients

III Livro de Resultados de Pesquisa do GRAED PUCPR: trabalhos científicos em análise econômica do direito

Trata-se de obra coletiva composta por trabalhos científicos de membros e parceiros do GRAED PUCPR, que se apresenta como mecanismo de promoção de pesquisas científicas na área de Análise Econômica do Direito. Para tanto, são consolidados comunicados científicos apresentados no III Encontro de Pesquisa do GRAED PUCPR, resultados do Programa Institucional de Bolsas de Iniciação Científica (PIBIC) realizados por membros do grupo e artigos científicos avaliados por pares e cujas pesquisas relacionam-se com os projetos do grupo