Planning complex engineer-to-order products

The design and manufacture of complex Engineer-to-Order products is characterised by uncertain operation durations, finite capacity resources and multilevel product structures. Two scheduling methods are presented to minimise expected costs for multiple products across multiple finite capacity resources. The first sub-optimises the operations sequence, using mean operation durations, then refines the schedule by perturbation. The second method generates a schedule of start times directly by random search with an embedded simulation of candidate schedules for evaluation. The methods are compared for industrial examples

Growing healthy sweetpotato: best practices for producing planting material

Sweetpotato is a major food crop in Papua New Guinea, with about 2.9 million tonnes grown each year. But sweetpotato is prone to pests and diseases, particularly viruses, which can significantly reduce yields. Because there are no varieties known to be resistant to viruses, the next best solution is to produce planting material that is free from infection, and to make this readily available to growers. This manual is aimed at researchers and technicians, and describes how to test for sweetpotato viruses and to keep vines free from infection. The methods described should help locals in PNG and other Pacific nations produce disease-free planting material for sweetpotato and other root and tuber crops

A discrete slug population model determined by egg production

Slugs are significant pests in agriculture (as well as a nuisance to gardeners), and it is therefore important to understand their population dynamics for the construction of efficient and effective control measures. Differential equation models of slug populations require the inclusion of large (variable) temporal delays, and strong seasonal forcing results in a non-autonomous system. This renders such models open to only a limited amount of rigorous analysis. In this paper, we derive a novel batch model based purely upon the quantity of eggs produced at different times of the year. This model is open to considerable reduction; from the resulting two variable discrete-time system it is possible to reconstruct the dynamics of the full population across the year and give conditions for extinction or global stability and persistence. Furthermore, the steady state temporal population distribution displays qualitatively different behavior with only small changes in the survival probability of slugs. The model demonstrates how small variations in the favorability of different years may result in widely different slug population fluctuations between consecutive years, and is in good agreement with field data

The social role of accounting: views and perceptions of the accounting community in Libya towards corporate social responsibility and accountability

The paper explores views and perceptions amongst members of the accounting community in Libya regarding the perceived basic features of the current corporate reporting and disclosure practices of the Libyan Business Organisations (LBOs). Extending these practices to embrace reporting and disclosure of social and environmental related information (CSR), and the extent to which notions of corporate social responsibility and accountability are acceptable in Libya are examined. Five groups of users of published accounts in Libya participated in the study, including academic accountants, financial managers (or accountants), government officials, bank credit officers and external auditors. A questionnaire survey of the 438 participants, drawing on the Al-khater and Naser (2003) study, was employed as the main data collection method. The findings demonstrate that currently most LBOs communicate limited information to a limited set of stakeholders. The disclosure of more social and environmental information was widely accepted and viewed as potentially leading to some beneficial socio-economic effects at the macro level. There was general agreement that the LBOs’ annual reports should reflect the interaction between their operations and the society in which they operate, recognizing the right of different stakeholders to information about the actions for which LBOs could be held responsible. The Law was viewed as the key source of establishing such responsibilities rather than professional guidelines

A quantitative PCR method to quantify ruminant DNA in porcine crude heparin

Heparin is a well-known glycosaminoglycan extracted from porcine intestines. Increased vigilance for transmissible spongiform encephalopathy in animal-derived pharmaceuticals requires methods to prevent the introduction of heparin from ruminants into the supply chain. The sensitivity, specificity, and precision of the quantitative polymerase chain reaction (PCR) make it a superior analytical platform for screening heparin raw material for bovine-, ovine-, and caprine-derived material. A quantitative PCR probe and primer set homologous to the ruminant Bov-A2 short interspersed nuclear element (SINE) locus (Mendoza-Romero et al. J. Food Prot. 67:550–554, 2004) demonstrated nearly equivalent affinities for bovine, ovine, and caprine DNA targets, while exhibiting no cross-reactivity with porcine DNA in the quantitative PCR method. A second PCR primer and probe set, specific for the porcine PRE1 SINE sequence, was also developed to quantify the background porcine DNA level. DNA extraction and purification was not necessary for analysis of the raw heparin samples, although digestion of the sample with heparinase was employed. The method exhibits a quantitation range of 0.3–3,000 ppm ruminant DNA in heparin. Validation parameters of the method included accuracy, repeatability, precision, specificity, range, quantitation limit, and linearity

Magnesium biofortification of Italian ryegrass (Lolium multiflorum L.) via agronomy and breeding as a potential way to reduce grass tetany in grazing ruminants

© 2019, The Author(s). Aim: Magnesium (Mg) deficiency (known as grass tetany) is a serious metabolic disorder that affects grazing ruminants. We tested whether Mg-fertiliser can increase Mg concentration of Italian ryegrasses (Lolium multiflorum L.) including a cultivar (cv. Bb2067; ‘Magnet’), bred to accumulate larger concentrations of Mg. Methods: Under controlled environment (CE) conditions, three cultivars (cv. Bb2067, cv. Bb2068, cv. RvP) were grown in low-nutrient compost at six fertiliser rates (0–1500μM MgCl2.6H2O). Under field conditions, the three cultivars in the CE condition and cv. Alamo were grown at two sites, and four rates of MgSO4 fertiliser application rates (0–200kgha−1 MgO). Multiple grass cuts were taken over two-years. Results: Grass Mg concentration increased with increasing Mg-fertiliser application rates in all cultivars and conditions. Under field conditions, cv. Bb2067 had 11–73% greater grass Mg concentration and smaller forage tetany index (FTI) than other cultivars across the Mg-fertiliser application rates, sites and cuts. Grass dry matter (DM) yield of cv. Bb2067 was significantly (p < 0.05) smaller than cv. Alamo. The effect of Mg-fertiliser rate on DM yield was not significant (p ≥ 0.05). Conclusions: Biofortification of grass with Mg through breeding and agronomy can improve the forage Mg concentration for grazing ruminants, even in high-growth spring grass conditions when hypomagnesaemia is most prevalent. Response to agronomic biofortification varied with cultivar, Mg-fertiliser rate, site and weather. The cost:benefit of these approaches and farmer acceptability, and the impact on cattle and sheep grazing on grasses biofortified with Mg requires further investigation

Sleep-wake sensitive mechanisms of adenosine release in the basal forebrain of rodents : an in vitro study

Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB) to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K+, AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS) inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state

Cognitive performance in light current users and ex-users of ecstasy (MDMA) and controls

Previous research has shown that heavy users of ecstasy may suffer impaired cognitive functioning, and the present study set out to investigate whether such impairment might also be found in light users or ex-users of ecstasy. Sixty subjects, comprising 20 current light users, 20 ex-users, and 20 non-users of ecstasy, were tested on an extensive battery of cognitive tests. Current light users of ecstasy achieved significantly lower scores on the overall cognitive test battery than did the non-users (p=0.011), though there were no significant differences on any individual subtests. However, the scores obtained by the ex-users of ecstasy did not differ significantly from those of the non-users. It was concluded that current light users of ecstasy show a small but significant cognitive impairment, but that no such impairment is detectable in ex-users who had abstained from the drug for at least 6 months

Integrating a newly developed BAC-based physical mapping resource for Lolium perenne with a genome-wide association study across a L. Perenne European ecotype collection identifies genomic contexts associated with agriculturally important traits

Background and Aims Lolium perenne (perennial ryegrass) is the most widely cultivated forage and amenity grass species in temperate areas worldwide and there is a need to understand the genetic architectures of key agricultural traits and crop characteristics that deliver wider environmental services. Our aim was to identify genomic regions associated with agriculturally important traits by integrating a bacterial artificial chromosome (BAC)-based physical map with a genome-wide association study (GWAS). Methods BAC-based physical maps for L. perenne were constructed from similar to 212 000 high-information-content fingerprints using Fingerprint Contig and Linear Topology Contig software. BAC clones were associated with both BAC-end sequences and a partial minimum tiling path sequence. A panel of 716 L. perenne diploid genotypes from 90 European accessions was assessed in the field over 2 years, and genotyped using a Lolium Infinium SNP array. The GWAS was carried out using a linear mixed model implemented in TASSEL, and extended genomic regions associated with significant markers were identified through integration with the physical map. Key Results Between similar to 3600 and 7500 physical map contigs were derived, depending on the software and probability thresholds used, and integrated with similar to 35 k sequenced BAC clones to develop a resource predicted to span the majority of the L. perenne genome. From the GWAS, eight different loci were significantly associated with heading date, plant width, plant biomass and water-soluble carbohydrate accumulation, seven of which could be associated with physical map contigs. This allowed the identification of a number of candidate genes. Conclusions Combining the physical mapping resource with the GWAS has allowed us to extend the search for candidate genes across larger regions of the L. perenne genome and identified a number of interesting gene model annotations. These physical maps will aid in validating future sequence-based assemblies of the L. perenne genome.UK Biotechnology and Biological Sciences Research Council [BB/J004405/1, BB/CSP1730/1, BB/G012342/1]; Germinal Holdings (UK); Syngenta (UK); Vialactia Biosciences (NZ)Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]