A software testing estimation and process control model

The control of the testing process and estimation of the resource required to perform testing is key to delivering a software product of target quality on budget. This thesis explores the use of testing to remove errors, the part that metrics and models play in this process, and considers an original method for improving the quality of a software product. The thesis investigates the possibility of using software metrics to estimate the testing resource required to deliver a product of target quality into deployment and also determine during the testing phases the correct point in time to proceed to the next testing phase in the life-cycle. Along with the metrics Clear ratio. Chum, Error rate halving. Severity shift, and faults per week, a new metric 'Earliest Visibility' is defined and used to control the testing process. EV is constructed upon the link between the point at which an error is made within development and subsequently found during testing. To increase the effectiveness of testing and reduce costs, whilst maintaining quality the model operates by each test phase being targeted at the errors linked to that test phase and the ability for each test phase to build upon the previous phase. EV also provides a measure of testing effectiveness and fault introduction rate by development phase. The resource estimation model is based on a gradual refinement of an estimate, which is updated following each development phase as more reliable data is available. Used in conjunction with the process control model, which will ensure the correct testing phase is in operation, the estimation model will have accurate data for each testing phase as input. The proposed model and metrics have been developed and tested on a large-scale (4 million LOC) industrial telecommunications product written in C and C++ running within a Unix environment. It should be possible to extend this work to suit other environments and other development life-cycles

The retention of differentiated function in cell culture : a study of the UDCK cell-line

The transporting properties of MDCK cells have been investigated upon epithelial monolayers grown upon permeable filter supports and mounted in Ussing chambers. When mounted without edge damage epithelial monolayers of MDCK cells (strain I) exhibited a transepithelial electrical resistance of 7.9 kO.cm2 and supported a small open-circuit potential (5.9 mV, basal-lateral surface positive) and a small short circuit current in agreement with the small magnitude of the net Na+, K+ and Cl- fluxes. Addition of adrenaline to the basal-lateral, but not the apical bathing solution stimulated a net basal-lateral to apical Cl- secretion, the magnitude of which accounted for the adrenaline stimulated short circuit current response. The Cl- secretion in MDCK cells exhibited many of the features of Cl- secretion in natural epithelia including sensitivity to the loop diuretics: furosemide, bumetamide and piretanide. In a number of secretory epithelia Cl- is accumulated across the basal-lateral cell border by a diuretic sensitive Na+K+Cl cotransport system. A comparison of the actions of the loop diuretics upon adrenaline stimulated Cl secretion and upon the cotransport system in MDCK cells provided strong but indirect evidence for a central role of the cotransport system in Cl secretion across MDCK cell monolayers. Measurement of influx and efflux across the apical and basal-lateral cell border demonstrated that the apical cell border was relatively impermeable to K. Influx across the basal-lateral border consisted of three major compenents; a ouabain sensitive , pump mediated, component; a diuretic sensitive component and a ouabain and diuretic insensitive flux component. K efflux across the basal-lateral cell border also consisted of these three components. Addition of adrenaline, ATP or A23187 to MDGK cells resulted in a transient stimulation of K+ efflux across both cell borders, although flux across the basal-lateral cell border was of greatest quantitative importance. Stimulation of K efflux was dependent upon the presence of Ca2+ in the external media and exhibited a similar pharmacology; sensitive to quinine and TEA, but insensitive to inhibition by apamin, as Ca2+-dependent K permeability?s in other, natural epithelia. Identification of an adrenaline stimulated Cl- secretory mechanism, a coupled Na + K + Cl cotransport system and a Ca2+-dependent K permeability in high resistance MDCK cells supports their use a model epithelium for the study of epithelial cell function

Evidence for complementary effects of code- and knowledge-focused reading instruction

There is growing recognition of the need to end the debate regarding reading instruction in favor of an approach that provides a solid foundation in phonics and other underlying language skills to become expert readers. We advance this agenda by providing evidence of specific effects of instruction focused primarily on the written code or on developing knowledge. In a grade 1 program evaluation study, an inclusive and comprehensive program with a greater code-based focus called Reading for All (RfA) was compared to a knowledge-focused program involving Dialogic Reading. Phonological awareness, letter word recognition, nonsense word decoding, listening comprehension, reading comprehension, written expression and vocabulary were measured at the beginning and end of the school year, and one year after in one school only. Results revealed improvements in all measures except listening comprehension and vocabulary for the RfA program at the end of the first school year. These gains were maintained for all measures one year later with the exception of an improvement in written expression. The Dialogic Reading group was associated with a specific improvement in vocabulary in schools from lower socioeconomic contexts. Higher scores were observed for RfA than Dialogic Reading groups at the end of the first year on nonsense word decoding, phonological awareness and written expression, with the differences in the latter two remaining significant one year later. The results provide evidence of the need for interventions to support both word recognition and linguistic comprehension to better reading comprehension

Algal food and fuel coproduction can mitigate greenhouse gas emissions while improving land and water-use efficiency

The goals of ensuring energy, water, food, and climate security can often conflict.Microalgae (algae) are being pursued as a feedstockfor both food and fuels—primarily due to algae’s high areal yield and ability to grow on non-arable land, thus avoiding common bioenergy-food tradeoffs. However, algal cultivation requires significant energy inputs that may limit potential emission reductions.We examine the tradeoffs associated with producing fuel andfood from algae at the energy–food–water–climate nexus.We use the GCAM integrated assessment model to demonstrate that algalfood production can promote reductions in land-use change emissions through the offset of conventional agriculture. However,fuel production, either via co-production of algal food and fuel or complete biomass conversion to fuel, is necessary to ensure long-term emission reductions, due to the high energy costs of cultivation. Cultivation of salt– water algae for food products may lead to substantial freshwater savings; but, nutrients for algae cultivation will need to be sourced from waste streams to ensure sustainability. By reducing the land demand of food production, while simultaneously enhancingfood and energy security, algae can further enable the development of terrestrial bioenergy technologies including those utilizing carbon capture and storage. Our results demonstrate that large-scale algae research and commercialization efforts should focus on developing both food and energy products to achieve environmental goals.https://iopscience.iop.org/article/10.1088/1748-9326/11/11/114006/metaPublished versio

Systematic reviews of and integrated report on the quantitative, qualitative and economic evidence base for the management of obesity in men

<b>Background</b><p></p> Obesity increases the risk of many serious illnesses such as coronary heart disease, type 2 diabetes and osteoarthritis. More men than women are overweight or obese in the UK but men are less likely to perceive their weight as a problem and less likely to engage with weight-loss services.<p></p> <b>Objective</b><p></p> The aim of this study was to systematically review evidence-based management strategies for treating obesity in men and investigate how to engage men in obesity services by integrating the quantitative, qualitative and health economic evidence base.<p></p> <b>Data sources</b><p></p> Electronic databases including MEDLINE, EMBASE, PsycINFO, the Cochrane Central Register of Controlled Trials, the Database of Abstracts of Reviews of Effects and the NHS Economic Evaluation Database were searched from inception to January 2012, with a limited update search in July 2012. Subject-specific websites, reference lists and professional health-care and commercial organisations were also consulted.<p></p> <b>Review methods</b><p></p> Six systematic reviews were conducted to consider the clinical effectiveness, cost-effectiveness and qualitative evidence on interventions for treating obesity in men, and men in contrast to women, and the effectiveness of interventions to engage men in their weight reduction. Randomised controlled trials (RCTs) with follow-up data of at least 1 year, or any study design and length of follow-up for UK studies, were included. Qualitative and mixed-method studies linked to RCTs and non-randomised intervention studies, and UK-based, men-only qualitative studies not linked to interventions were included. One reviewer extracted data from the included studies and a second reviewer checked data for omissions or inaccuracies. Two reviewers carried out quality assessment. We undertook meta-analysis of quantitative data and a realist approach to integrating the qualitative and quantitative evidence synthesis.<p></p> <b>Results</b><p></p> From a total of 12,764 titles reviewed, 33 RCTs with 12 linked reports, 24 non-randomised reports, five economic evaluations with two linked reports, and 22 qualitative studies were included. Men were more likely than women to benefit if physical activity was part of a weight-loss programme. Reducing diets tended to produce more favourable weight loss than physical activity alone (mean weight change after 1 year from a reducing diet compared with an exercise programme -3.2 kg, 95% CI -4.8 kg to -1.6 kg). The type of reducing diet did not affect long-term weight loss. A reducing diet plus physical activity and behaviour change gave the most effective results. Low-fat reducing diets, some with meal replacements, combined with physical activity and behaviour change training gave the most effective long-term weight change in men [-5.2 kg (standard error 0.2 kg) after 4 years]. Such trials may prevent type 2 diabetes in men and improve erectile dysfunction. Although fewer men joined weight-loss programmes, once recruited they were less likely to drop out than women (difference 11%, 95% CI 8% to 14%). The perception of having a health problem (e.g. being defined as obese by a health professional), the impact of weight loss on health problems and desire to improve personal appearance without looking too thin were motivators for weight loss amongst men. The key components differ from those found for women, with men preferring more factual information on how to lose weight and more emphasis on physical activity programmes. Interventions delivered in social settings were preferred to those delivered in health-care settings. Group-based programmes showed benefits by facilitating support for men with similar health problems, and some individual tailoring of advice assisted weight loss in some studies. Generally, men preferred interventions that were individualised, fact-based and flexible, which used business-like language and which included simple to understand information. Preferences for men-only versus mixed-sex weight-loss group programmes were divided. In terms of context, programmes which were cited in a sporting context where participants have a strong sense of affiliation showed low drop out rates and high satisfaction. Although some men preferred weight-loss programmes delivered in an NHS context, the evidence comparing NHS and commercial programmes for men was unclear. The effect of family and friends on participants in weight-loss programmes was inconsistent in the evidence reviewed - benefits were shown in some cases, but the social role of food in maintaining relationships may also act as a barrier to weight loss. Evidence on the economics of managing obesity in men was limited and heterogeneous.<p></p> <b>Limitations</b><p></p> The main limitations were the limited quantity and quality of the evidence base and narrow outcome reporting, particularly for men from disadvantaged and minority groups. Few of the studies were undertaken in the UK.<p></p> <b>Conclusions</b><p></p> Weight reduction for men is best achieved and maintained with the combination of a reducing diet, physical activity advice or a physical activity programme, and behaviour change techniques. Tailoring interventions and settings for men may enhance effectiveness, though further research is needed to better understand the influence of context and content. Future studies should include cost-effectiveness analyses in the UK setting

Regenerability of fly-ash derived zeolite NaP1: Evaluation via copper recovery

Effective regeneration of adsorbents is considered as one of the essential qualities for commercial use. However, most of the studies have only reported the adsorption properties and overlooked the reuse of adsorbents. In this study, we determined the regenerability and reusability of fly-ash derived zeolite (FADZ) NaP1. These adsorbents have become popular to remove pollutants from water, including toxic metals, since they are less expensive, compared to their counterparts, and can be synthesized from a waste product. We evaluated the efficiency of copper (Cu2+) ions recovery from water using multiple regeneration solutions due to medium adsorption selectivity towards Cu2+. We determined the time required for the regeneration using acid, base, and salt solutions. The suitable pH and solution while maintaining the structure of the zeolite were studied. Up to 90% recovery was achieved via three successive regenerations, each taking 3 h using 3 M KCl and 3 M NaCl solutions. X-ray diffraction (XRD) and fluorescence showed changes in structure after regeneration at pH < 5 and contact time <6 h. The desorption kinetics using KCl solutions can be described by pseudo-second order model. Freundlich model represents the desorption of Cu2+ ions better than the Langmuir model due to regression coefficient (R2) values in the range of 0.998–1.0. Results suggest a strong ion exchange mechanism as the main driving force for desorption. The type of anions (such as Cl− and OH−) in solution influences regeneration in addition to the exchanging cation

Heavy Metal Removal from Aqueous Solutions Using Fly-Ash Derived Zeolite NaP1

Fly-ash derived zeolites have recently -received great attention as cheaper adsorbents to remove heavy metals from water since they can be synthesized from a waste product. In this study, we evaluated the single- and multi-cation adsorption efficiencies of fly-ash derived NaP1 for the removal of zinc (Zn), copper (Cu) and lead (Pb). We also determined precipitation and leaching from NaP1 during the adsorption. Results showed that the uptake capacities for Zn (34 mg/g) and Pb (192 mg/g) were higher than other fly-ash derived NaP1 and adsorbents such as clinoptilolite and activated carbon. The Cu uptake was estimated ~ 14.6 mg/g. Pb2+  > Cu2+  > Zn2+ is the order for the metal cation selectivity of NaP1. Langmuir adsorption isotherm and pseudo-second order kinetic model fitted best for all elements. The metal uptake occurred in 15 min. Diffusion of hydrated metals through microporous channels is the rate-determining step

Marine microalgae commercial production improves sustainability of global fisheries and aquaculture

publishedVersio

Benefits of hybrid lateral transshipments in multi-item inventory systems under periodic replenishment

Lateral transshipments are a method of responding to shortages of stock in a network of inventory-holding locations. Conventional reactive approaches only seek to meet immediate shortages. The study proposes hybrid transshipments which exploit economies of scale by moving additional stock between locations to prevent future shortages in addition to meeting immediate ones. The setting considered is motivated by retailers who operate networks of outlets supplying car parts via a system of periodic replenishment. It is novel in allowing non-stationary stochastic demand and general patterns of dependence between multiple item types. The generality of our work makes it widely applicable. We develop an easy-to-compute quasi-myopic heuristic for determining how hybrid transshipments should be made. We obtain simple characterizations of the heuristic and demonstrate its strong cost performance in both small and large networks in an extensive numerical study

Anthropogenic modifications to fire regimes in the wider Serengeti‐Mara ecosystem

Fire is a key driver in savannah systems and widely used as a land management tool. Intensifying human land uses are leading to rapid changes in the fire regimes, with consequences for ecosystem functioning and composition. We undertake a novel analysis describing spatial patterns in the fire regime of the Serengeti‐Mara ecosystem, document multidecadal temporal changes and investigate the factors underlying these patterns. We used MODIS active fire and burned area products from 2001 to 2014 to identify individual fires; summarizing four characteristics for each detected fire: size, ignition date, time since last fire and radiative power. Using satellite imagery, we estimated the rate of change in the density of livestock bomas as a proxy for livestock density. We used these metrics to model drivers of variation in the four fire characteristics, as well as total number of fires and total area burned. Fires in the Serengeti‐Mara show high spatial variability—with number of fires and ignition date mirroring mean annual precipitation. The short‐term effect of rainfall decreases fire size and intensity but cumulative rainfall over several years leads to increased standing grass biomass and fuel loads, and, therefore, in larger and hotter fires. Our study reveals dramatic changes over time, with a reduction in total number of fires and total area burned, to the point where some areas now experience virtually no fire. We suggest that increasing livestock numbers are driving this decline, presumably by inhibiting fire spread. These temporal patterns are part of a global decline in total area burned, especially in savannahs, and we caution that ecosystem functioning may have been compromised. Land managers and policy formulators need to factor in rapid fire regime modifications to achieve management objectives and maintain the ecological function of savannah ecosystems