The Stochastic Container Relocation Problem

The Container Relocation Problem (CRP) is concerned with finding a sequence of moves of containers that minimizes the number of relocations needed to retrieve all containers, while respecting a given order of retrieval. However, the assumption of knowing the full retrieval order of containers is particularly unrealistic in real operations. This paper studies the stochastic CRP (SCRP), which relaxes this assumption. A new multi-stage stochastic model, called the batch model, is introduced, motivated, and compared with an existing model (the online model). The two main contributions are an optimal algorithm called Pruning-Best-First-Search (PBFS) and a randomized approximate algorithm called PBFS-Approximate with a bounded average error. Both algorithms, applicable in the batch and online models, are based on a new family of lower bounds for which we show some theoretical properties. Moreover, we introduce two new heuristics outperforming the best existing heuristics. Algorithms, bounds and heuristics are tested in an extensive computational section. Finally, based on strong computational evidence, we conjecture the optimality of the “Leveling” heuristic in a special “no information” case, where at any retrieval stage, any of the remaining containers is equally likely to be retrieved next

The Stochastic Container Relocation Problem

© 2018 INFORMS. The container relocation problem (CRP) is concerned with finding a sequence of moves of containers that minimizes the number of relocations needed to retrieve all containers, while respecting a given order of retrieval. However, the assumption of knowing the full retrieval order of containers is particularly unrealistic in real operations. This paper studies the stochastic CRP, which relaxes this assumption. A new multistage stochastic model, called the batch model, is introduced, motivated, and compared with an existing model (the online model). The two main contributions are an optimal algorithm called Pruning-Best-First-Search (PBFS) and a randomized approximate algorithm called PBFS-Approximate with a bounded average error. Both algorithms, applicable in the batch and online models, are based on a new family of lower bounds for which we show some theoretical properties. Moreover, we introduce two new heuristics outperforming the best existing heuristics. Algorithms, bounds, and heuristics are tested in an extensive computational section. Finally, based on strong computational evidence, we conjecture the optimality of the "leveling" heuristic in a special "no information" case, where, at any retrieval stage, any of the remaining containers is equally likely to be retrieved next

Allergic fungal rhinosinusitis caused by Neoscytalidium dimidiatum: A case report: Allergic fungal rhinosinusitis due to Neoscytalidium dimidiatum

Neoscytalidium dimidiatum is a rare dematiaceous fungus that was first described in 1916 as Dothiorella mangiferae. From the standpoint of epidemiology and therapy, early detection of fungal rhinosinusitis (FRS), the causative agents, and their associated risk factors can improve the therapeutic outcome and decrease the mortality rates among patients. In this study, we report a 34-year-old Iranian female patient with allergic bronchopulmonary aspergillosis (ABPA), who presented to our facility with an 8-year history of chronic fungal sinusitis, drug-resistant asthma, pneumonia, bronchitis, post-nasal discharge, nasal obstruction, nasal polyposis, and anemia. The patient was subjected to diagnostic nasal endoscopy and computed tomography (CT) scan of paranasal sinuses, as well as routine, complementary mycological, and molecular methods, which confirmed the diagnosis of allergic fungal rhinosinusitis in patients with ABPA. Neoscytalidium dimidiatum was isolated from the sinus of the patient. Results of in vitro susceptibility tests indicated that the case isolate was susceptible to amphotericin B and itraconazole at concentrations which are commonly achieved in patients receiving recommended dosages for invasive mycoses (0.25 to 0.75 mg/kg of body weight daily for amphotericin B and 100 to 400 mg daily for itraconazole) and resistant in vitro to caspofungin, voriconazole, and posaconazole. The patient was successfully treated with amphotericin B / itraconazole + postoperative oral corticosteroids (OCS). Neoscytalidium dimidiatum infection should be considered as a possible additional factor in the etiology of AFRS, especially in immunocompromised patients

Distribution of invasive fungal infections: Molecular epidemiology, etiology, clinical conditions, diagnosis and risk factors: A 3-year experience with 490 patients under intensive care

Recently, the prevalence of invasive fungal infections (IFIs) is rising. The global mortality rate of IFIs is 10�49. This study aimed to determine the prevalence, the causative agents, and the risk factors associated with the invasive fungal infections in a tertiary health center to provide valid decision-grounds for healthcare professionals to effectively prevent, control, and treat fungal infections. The current study was conducted on 1477 patients suspected to have systemic fungal infections from different units of the hospital. After screening using routine mycological examination, the patients were confirmed with complementary mycological and molecular methods. Patients were included based on the confirmed diagnosis of IFI and excluded based on lack of a microbiologically and histologically proven diagnosis of IFI. Of the 1477 patients recruited in this study, confirmed cases of fungal infection were 490 (169 proven; 321 cases probable). Among the fungi recovered, Candida species had the highest frequency 337 (68.8) followed by Aspergillus species 108 (22.1), Zygomycetes species 21 (4.3), non-Candida yeast 9 (1.8). Others were black fungi 5 (1), mycetoma agents 5 (1), Fusarium 4 (0.8), and Trichoderma (0.2). Hematologic malignancies and diabetes mellitus were the most common underlying diseases among IFI-confirmed patients. This study observed an increased frequency of invasive candidiasis with non-albicans Candida and other invasive saprophytic fungal infections. The increased rate of invasive candidiasis with non-albicans agents highlights a new perspective in the epidemiology and treatment of invasive fungal infections. © 2020 Elsevier Lt

Distribution of invasive fungal infections: Molecular epidemiology, etiology, clinical conditions, diagnosis and risk factors: A 3-year experience with 490 patients under intensive care

Recently, the prevalence of invasive fungal infections (IFIs) is rising. The global mortality rate of IFIs is 10-49. This study aimed to determine the prevalence, the causative agents, and the risk factors associated with the invasive fungal infections in a tertiary health center to provide valid decision-grounds for healthcare professionals to effectively prevent, control, and treat fungal infections. The current study was conducted on 1477 patients suspected to have systemic fungal infections from different units of the hospital. After screening using routine mycological examination, the patients were confirmed with complementary mycological and molecular methods. Patients were included based on the confirmed diagnosis of IFI and excluded based on lack of a microbiologically and histologically proven diagnosis of IFI. Of the 1477 patients recruited in this study, confirmed cases of fungal infection were 490 (169 proven; 321 cases probable). Among the fungi recovered, Candida species had the highest frequency 337 (68.8) followed by Aspergillus species 108 (22.1), Zygomycetes species 21 (4.3), non-Candida yeast 9 (1.8). Others were black fungi 5 (1), mycetoma agents 5 (1), Fusarium 4 (0.8), and Trichoderma (0.2). Hematologic malignancies and diabetes mellitus were the most common underlying diseases among IFI-confirmed patients. This study observed an increased frequency of invasive candidiasis with non-albicans Candida and other invasive saprophytic fungal infections. The increased rate of invasive candidiasis with non-albicans agents highlights a new perspective in the epidemiology and treatment of invasive fungal infections

Different karyotypes, same disease?

High grade aneuploidies of the sex chromosomes (HGA) presenting with a male phenotype comprise a vast and heterogenous group of very rare conditions, once considered as “variants” of Klinefelter syndrome (KS). This association with KS was mainly based on the presence of at least one supernumerary X chromosome, high stature and hypergonadotropic hypogonadism with severe testicular hypotrophy. However, many of the shared features show elevated severity in HGA compared to KS, while many others are unique to HGA. Different karyotypes arise from mechanisms peculiar to each HGA syndrome. Age at diagnosis ranges from pre-natal to early adulthood and an increased mortality ratio has been reported in these patients, mostly from respiratory diseases and congenital abnormalities. Among physical features the most common include: facial dysmorphisms, radioulnar synostosis, clinodactyly, impaired genital development (e.g. micropenis, cryptorchidism) renal dysplasia, cardiac malformations and taurodontism. Almost all patients show learning disabilities and intellectual deficits are common, with full scale IQs as low as 20-40, with verbal performances being the most affected. Behaviorally attention deficit-hyperactivity disorder (ADHD) and autism spectrum disorders are common, and patients’ temper can range from shyness to aggressiveness. Androgen replacement therapy is often necessary to start or complete pubertal development and is effective in ameliorating neuropsychiatric symptoms to some extent. Fertility is severely impaired, with all HGA patients being azoospermic and is often not a concern given the concurrent intellectual disability, although access to assisted reproduction techniques can be evaluated on a case-by-case basis