A decision model for natural oil buying policy under uncertainty

A manufacturer, in a fast moving consumer goods industry, buys Natural oils from a number of oil suppliers world-wide. The prices of these oils are the major raw material cost in producing the consumer goods, which are also sold world-wide. The volatility in the international prices of the Natural oils has signi¯cant impact on the planning and budgets decisions. Since the oils are bought and the ¯nished products are sold in markets throughout the world, the manufacturer is exposed to a variety of market uncertainties and the resulting risks. These uncertainties are the raw material prices, the demand and the therefore the selling prices for the finished goods- all of which influence the profitability of the manufacturing firm. The risks can be minimised by entering into futures contract of appropriate duration, that is, by following a schedule of "forward"' purchase of oil (with specific series of future delivery dates) with the oil suppliers. We formulate this problem as a two-stage Stochastic Program (SP) using the futures and the spot prices for the Natural oil. This SP model gives robust decisions that hedge against the uncertainties in the Natural oil prices and the demand for the finished products. The uncertainty in the oil prices and the demand are modelled through a scenario generator. We have constructed a decision support system (DSS) that integrates the SP model, the scenario generator and the solution algorithm. This DSS also provides the decision maker a profile of the risk and return exposures for different policies

Sociocultural understandings of the silent period: young bilingual learners in early years settings

This briefing draws from longitudinal Doctoral research (Bligh, 2011) to re-examine the emergent stage of English language acquisition, the silent period, through the experiences of two early years bilingual learners. Historical understandings of Vygotsky (1986) provide the platform through which sociocultural learning theory is applied in relation to the silent period. Legitimate peripheral participation (Lave and Wenger, 1991), is examined as a workable concept through which to explore the initial learning trajectory of an emergent bilingual learner whilst negotiating participation within, through and beyond an early years community of practice. The initial research employed multi-method ethnographic approach to data gathering, including participant observations, unstructured interviews with monolingual participants, participant narratives and significant auto-ethnographic accounts. In this briefing the researcher focuses upon ‘gaze following’ (Flewitt, 2005) as an adjunct to participant observations. The findings are revealed through a two stage analytic process. Data is initially funnelled through thematic analysis, (Braun and Clarke, 2006) and tested out against sociocultural theorising. The deductive process highlights nine vignettes which present the silent period as a crucial time for learning. One professional narrative account and one significant vignette are examined in this briefing. Examining the silent period through a sociocultural lens reveals the initial stage of language acquisition as a significant, but lesser acknowledged contribution to learning in the early years community of practice. Key words: bilingual; silent period; legitimate peripheral participation; sociocultural; ethnographic; participation

Sex-change chemicals and their influence on the brain.

The potential for man-made chemicals to mimic or antagonise natural hormones is a controversial issue, but one for which increasing amounts of evidence are being gathered worldwide. The controversy surrounds not so much the matter of whether these chemicals can mimic hormones in vitro--this phenomenon has been widely accepted in the scientific world - but more whether, as a result, they can disrupt reproduction in a wildlife situation. It has, nevertheless, been acknowledged that many wildlife populations are exhibiting reproductive and/or developmental abnormalities such as intersex gonads in wild roach populations in the U.K. and various reproductive disorders in alligators in Lake Apopka, Florida. However, the causative agents for many of these effects are difficult to specify, due to the extensive mixtures of chemicals--each of which may act via different pathways--to which wild populations are exposed, together with the wide variability observed even in natural (uncontaminated) habitats. As a result, any information detailing fundamental mechanism of action of the so-called endocrine disrupting chemicals (EDCs) is of use in determining whether or not these chemicals, as they are present in the environment, may in fact be capable of causing some of the effects observed in wildlife over recent years

The relationships between the HIV test interval, demographic factors and HIV disease progression

Individuals developing an HIV seroconversion illness may experience rapid disease progression. Information on seroconversion illness is rarely collected in most cohort studies; thus the aim of this study was to assess the value of the HIV test interval (the time between last negative and first positive HIV tests) as a proxy for seroconversion illness. Among 8229 seroconverters, test intervals ranged from 0-5282 days, and varied by gender, risk group, age and calendar year of seroconversion. Those with intervals less than or equal to 31 days had an increased hazard of AIDS (RH 1.42, P = 0.07), which was reduced slightly after adjusting for baseline factors, calendar year of follow-up, treatment and the declining CD4 count, but there was no effect on survival. Thus, it appears that if information on acute seroconversion illness is not available, then analyses of progression to AIDS in seroconverter studies could use a short test interval as a proxy measure

Avoiding the perfect storm of juror contempt

Concern over juror contempt and improper conduct is one of the factors that prompted the Law Commission’s early review of Contempt of Court. This article argues that any reform of the law of contempt in relation to juries and jury trials should be based on rigorous and reliable empirical evidence, not anecdotal evidence, exceptional cases or untested assumptions about juries. It reports the first findings of recent research conducted with juries at Crown Courts examining juror understanding of contempt, awareness of recent prosecutions of jurors, willingness to report improper conduct, as well desire for deliberation guidance and written judicial directions. Based on empirical evidence, this article argues for a three-pronged approach to minimising juror contempt in the new media age. It also argues that calls for the removal or relaxation of s.8 of the Contempt of Court Act are misguided and based on a myth that the current law prevents detailed jury research

THE EFFECT OF CMV INFECTION ON PROGRESSION OF HUMAN-IMMUNODEFICIENCY-VIRUS DISEASE IN A COHORT OF HEMOPHILIC MEN FOLLOWED FOR UP TO 13 YEARS FROM SEROCONVERSION

The effect of prior infection with cytomegalovirus (CMV) on progression of HIV disease in a cohort of 111 men with haemophilia was studied after 13 years followup. The relative hazards associated with CMV positivity on progression to AIDS, death and a CD4 count of 0.05 x 10(9)/l were 2.28, 2.42 and 2.34, respectively. CMV seropositive patients were significantly older than the seronegative and this was controlled for by using a Cox proportional hazards model. The relative hazards for the three endpoints decreased to 1.89, 1.82 and 1.93 respectively and were marginally non-significant (P = 0.05, 0.08 and 0.08 for the three endpoints respectively). We conclude that this cohort continues to show evidence of a 'co-factor' effect associated with prior infection with CMV which is confounded by age but not completely explained by age differences. The potential biological significance of these results is discussed in the context of recent controlled clinical trials which show a survival benefit from long-term high-dose acyclovir, a drug with activity in vivo against CMV and other herpesviruses

Modelling of mathematical programs: An analysis of strategy and an outline description of a computer assisted system

The salient components of the mathematical programming modeling activity are first analysed. Earlier generation systems such as program generators and procedural (modelling) languages are briefly discussed. A proposal for a computer assisted modelling scheme is then put forward. The proposed system contrasts with the earlier approaches in that no computer programming expertise is required on the part of the modeller. A mathematical programming model is usually constructed by progressive definition of dimensions, data tables, model variables, model constraints and the matrix coefficients which connect the last two entities. The philosophy and design of the experimental system supports this approach to model description. This aspect is illustrated by a few examples. The introduction of computer assistance in structuring of the data and the resulting model is novel and is in line with recent developments in friendly and flexible user interface

An investigation into the effect of floor colour on the behaviour of the horse

Adverse reactions of the domestic horse to environmental stimuli can be problematic in training and management. Hesitation and alarm reactions to visual features of the ground can occur in both ridden work and when handling horses. To assess the effect of one visual feature (colour) on the behaviour of the domestic horse, the reactions of sixteen riding horses to eight different coloured mats were recorded. The effect of stimulus position on these reactions was assessed by presenting them in two different positions, either on the ground (where the horses had to walk over them) or against a wall (where the horses walked past them). Each colour/position combination was presented twice in order to assess the effect of previous experience. An alleyway was constructed to allow the horses to be tested unconstrained and freely walking throughout. The time taken to traverse the alleyway and the observed reaction to the colour was recorded

Band engineering in dilute nitride and bismide semiconductor lasers

Highly mismatched semiconductor alloys such as GaNAs and GaBiAs have several novel electronic properties, including a rapid reduction in energy gap with increasing x and also, for GaBiAs, a strong increase in spin orbit- splitting energy with increasing Bi composition. We review here the electronic structure of such alloys and their consequences for ideal lasers. We then describe the substantial progress made in the demonstration of actual GaInNAs telecomm lasers. These have characteristics comparable to conventional InP-based devices. This includes a strong Auger contribution to the threshold current. We show, however, that the large spin-orbit-splitting energy in GaBiAs and GaBiNAs could lead to the suppression of the dominant Auger recombination loss mechanism, finally opening the route to efficient temperature-stable telecomm and longer wavelength lasers with significantly reduced power consumption.Comment: 27 pages, 11 figure