Integrated production-distribution systems : Trends and perspectives

During the last two decades, integrated production-distribution problems have attracted a great deal of attention in the operations research literature. Within a short period, a large number of papers have been published and the field has expanded dramatically. The purpose of this paper is to provide a comprehensive review of the existing literature by classifying the existing models into several different categories based on multiple characteristics. The paper also discusses some trends and list promising avenues for future research

Data-driven Determination of Disease Markers’ Threshold Values in Rot-affected Wine Grapes

Grapevine bunch rot is detrimental to grape and wine quality. Traditionally, detecting and quantifyingthe severity of rot infection is executed visually. This study aimed at defining local, area-specific thresholdvalues of rot-associated disease markers. This is a first step towards making informed decisions aboutthe quality of grapes delivered at winery intake. Viticulturists visually assessed on-vine rot infection innine white wine grape cultivars. Results showed that severity ratings were consistent between assessors.Chemical analyses of the grape must from these assessed samples were done. Multiple factor analysis (MFA)showed that rot severity was positively correlated with glycerol, alcohol, gluconic acid and acetic acidconcentrations. As severity increased, gluconic acid, glycerol, alcohol, Brix, acetic acid and total titratableacidity (TA) concentrations also increased. Following the probability chosen for sensitivity and specificity,grape rot indicators’ threshold values in white grape must are as follow: Alcohol ≥ 0.10 %v/v; acetic acid≥ 0.17 g/L; glycerol ≥ 0.79 g/L; gluconic acid ≥ 0.99 g/L; TA ≥ 8.86 g/L. Statistical determined thresholdvalues differentiating between rot-affected and healthy grape must, would eliminate the subjectivity andbias associated with visual assessments

Anxiety sensitivity in school attending youth : exploratory and confirmatory factor analysis of the 18-item CASI in a multicultural South African sample

CITATION: Martin, L., Kidd, M. & Seedat, S. 2016. Anxiety sensitivity in school attending youth: exploratory and confirmatory factor analysis of the 18-item CASI in a multicultural South African sample. Frontiers in Psychology, 6:1996, doi:10.3389/fpsyg.2015.01996.The original publication is available at http://journal.frontiersin.org/journal/psychologyENGLISH SUMMARY : Anxiety sensitivity (AS) is a risk factor for the development of anxiety disorders in youth. To date, the applicability of the Childhood Anxiety Sensitivity Index (CASI) in youth from a low or middle income country (LMIC) setting on the African continent has not been assessed. A representative sample of 1149 secondary school learners from 29 schools in Cape Town, South Africa, participated in the study. Participants completed the CASI on a single occasion. One-, two-, and four-factor models of the CASI were assessed. A one-factor solution that comprised items predominantly represented by physical concerns appeared to provide the best fit to our data, however, relatively low variance (26%) was explained. Subsequent item deletion resulted in a 9-item ‘physical concerns’ factor that showed good construct reliability (0.83) but also explained a low amount of variance (35%). In terms of gender, a one-factor model provided the best fit, however, low variance was explained (i.e., 25%). Configural, metric and scalar invariance of the CASI by gender was determined. Our results suggest that the 18-item CASI is not applicable to our target population and may require adaptation in this population; however, replication of this study in other multicultural adolescent samples in South Africa is first needed to further assess the validity of the AS construct as measured by the CASI.http://journal.frontiersin.org/article/10.3389/fpsyg.2015.01996/fullPublisher's versio

Comparison of three commercial sparse-matrix crystallization screens

Sparse-matrix sampling using commercially available crystallization screen kits has become the most popular way of determining the preliminary crystallization conditions for macromolecules. In this study, the efficiency of three commercial screening kits, Crystal Screen and Crystal Screen 2 (Hampton Research), Wizard Screens I and II (Emerald BioStructures) and Personal Structure Screens 1 and 2 (Molecular Dimensions), has been compared using a set of 19 diverse proteins. 18 proteins yielded crystals using at least one crystallization screen. Surprisingly, Crystal Screens and Personal Structure Screens showed dramatically different results, although most of the crystallization formulations are identical as listed by the manufacturers. Higher molecular weight polyethylene glycols and mixed precipitants were found to be the most effective precipitants in this study

Glutamate dehydrogenase and glutamine synthetase are regulated in response to nitrogen availability in Myocbacterium smegmatis

<p>Abstract</p> <p>Background</p> <p>The assimilation of nitrogen is an essential process in all prokaryotes, yet a relatively limited amount of information is available on nitrogen metabolism in the mycobacteria. The physiological role and pathogenic properties of glutamine synthetase (GS) have been extensively investigated in <it>Mycobacterium tuberculosis</it>. However, little is known about this enzyme in other mycobacterial species, or the role of an additional nitrogen assimilatory pathway via glutamate dehydrogenase (GDH), in the mycobacteria as a whole. We investigated specific enzyme activity and transcription of GS and as well as both possible isoforms of GDH (NAD⁺- and NADP⁺-specific GDH) under varying conditions of nitrogen availability in <it>Mycobacterium smegmatis </it>as a model for the mycobacteria.</p> <p>Results</p> <p>It was found that the specific activity of the aminating NADP⁺-GDH reaction and the deaminating NAD⁺-GDH reaction did not change appreciably in response to nitrogen availability. However, GS activity as well as the deaminating NADP⁺-GDH and aminating NAD⁺-GDH reactions were indeed significantly altered in response to exogenous nitrogen concentrations. Transcription of genes encoding for GS and the GDH isoforms were also found to be regulated under our experimental conditions.</p> <p>Conclusions</p> <p>The physiological role and regulation of GS in <it>M. smegmatis </it>was similar to that which has been described for other mycobacteria, however, in our study the regulation of both NADP⁺- and NAD⁺-GDH specific activity in <it>M. smegmatis </it>appeared to be different to that of other Actinomycetales. It was found that NAD⁺-GDH played an important role in nitrogen assimilation rather than glutamate catabolism as was previously thought, and is it's activity appeared to be regulated in response to nitrogen availability. Transcription of the genes encoding for NAD⁺-GDH enzymes seem to be regulated in <it>M. smegmatis </it>under the conditions tested and may contribute to the changes in enzyme activity observed, however, our results indicate that an additional regulatory mechanism may be involved. NADP⁺-GDH seemed to be involved in nitrogen assimilation due to a constitutive aminating activity. The deaminating reaction, however was observed to change in response to varying ammonium concentrations which suggests that NADP⁺-GDH is also regulated in response to nitrogen availability. The regulation of NADP⁺-GDH activity was not reflected at the level of gene transcription thereby implicating post-transcriptional modification as a regulatory mechanism in response to nitrogen availability.</p

Altered cognitive response to serotonin challenge as a candidate endophenotype for obsessive-compulsive disorder.

RATIONALE: Obsessive-compulsive disorder (OCD) implicates dysfunction of orbitofrontal and insula-related circuitry and of the serotonin system. There is an on-going search in psychiatry for intermediate biological markers, termed 'endophenotypes', that exist not only in patients with a given disorder but also in their clinically unaffected first-degree relatives. OBJECTIVE: Pharmacological challenge is recognized as a means of eliciting an endophenotype, but this strategy has yet to be used in OCD. METHODS: Twenty-three OCD patients without comorbidities (12 [52.2 %] female), 13 clinically asymptomatic first-degree relatives of OCD patients (11 [84.6 %] female) and 27 healthy controls (16 [59.3 %] female) received single-dose escitalopram (20 mg) and placebo in a randomized double-blind crossover design. Effects of treatment on decision-making were quantified using the Cambridge Gamble Task (CGT) in conjunction with a mixed model analysis of covariance (ANCOVA). RESULTS: There was a significant interaction between serotonergic challenge and group for risk adjustment on the CGT (F = 4.1406; p = 0.02). Only controls showed a significant placebo-drug change in risk adjustment (p = 0.02; versus p > 0.10). Numerically, escitalopram was associated with increase in risk adjustment in controls and reductions in the other groups. Change in risk adjustment was similar in OCD patients and relatives (p = 0.806) and differed significantly from controls (p = 0.007; p = 0.041, respectively). CONCLUSIONS: Individuals with OCD, and first-degree relatives, showed an altered cognitive response to serotonin challenge. This is the first demonstration of a candidate pharmacological challenge endophenotype for the disorder. Future work should confirm these findings in a larger sample size and ideally extend them to other cognitive paradigms, utilizing functional neuroimaging.This work was supported by the Medical Research Council of South Africa, the Obsessive-Compulsive Foundation (Prof Stein), the National Research Foundation of South Africa (Prof Lochner), an unrestricted grant from Lundbeck H/S and by a Starter Grant for Clinical Lecturers from the Academy of Medical Sciences UK (Dr Chamberlain).This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00213-015-4172-

Passenger- and operator-oriented scheduling of large railway projects

The continued development and renewal of railway infrastructure and technology is necessary to enable railway operators to provide high quality services subject to ever increasing demand. However, the execution of large infrastructure projects causes disturbances in the network due to the occupation of infrastructure over extended periods of time. In this paper we propose a multiobjective project scheduling optimization model for railway infrastructure projects that takes inconvenience caused to users of the infrastructure into account. We illustrate how the model can be used in an interactive way by planners based on their preferences, and we show that Pareto optimal solutions can be found in reasonable time using instances with realistic features. The result is a decision support model to aid infrastructure project planners in ensuring that passenger and operator inconvenience are also taken into account