Estimating software project effort using analogies

Accurate project effort prediction is an important goal for the software engineering community. To date most work has focused upon building algorithmic models of effort, for example COCOMO. These can be calibrated to local environments. We describe an alternative approach to estimation based upon the use of analogies. The underlying principle is to characterise projects in terms of features (for example, the number of interfaces, the development method or the size of the functional requirements document). Completed projects are stored and then the problem becomes one of finding the most similar projects to the one for which a prediction is required. Similarity is defined as Euclidean distance in n-dimensional space where n is the number of project features. Each dimension is standardised so all dimensions have equal weight. The known effort values of the nearest neighbours to the new project are then used as the basis for the prediction. The process is automated using a PC based tool known as ANGEL. The method is validated on nine different industrial datasets (a total of 275 projects) and in all cases analogy outperforms algorithmic models based upon stepwise regression. From this work we argue that estimation by analogy is a viable technique that, at the very least, can be used by project managers to complement current estimation techniques

Price feedback and hybrid diffusions in finance

It is well-known that the probabilistic behaviour of financial asset returns is not captured well by the classical Black-Scholes model. The true behaviour will never be perfectly captured in any model, but insight is continually being obtained into our understanding of more sophisticated and realistic models. Much research has been published recently exploring the use of L\'{e}vy process models, which maintain the original \emph{independent stationary increments} assumption present in the Black-Scholes model, but incorporate jumps in the modelling. This investigation seeks to motivate a new class of models, throwing out the stationary increments hypothesis. We argue that certain techniques of trading decision-making are not independent of previous price movements, and the returns, being driven by the trade order flow, will reflect that. From here, we develop two particular such models, which are both diffusion models, and study them for their probabilistic behaviour. The first of these models is a hybrid of the arithmetic and geometric Brownian motions, which has transition probabilities expressible in terms of a spectral expansion involving Legendre functions. The second is a hybrid of the arithmetic Brownian motion and the Cox-Ingersoll-Ross process, and its spectral expansions involve the confluent hypergeometric functions. Having developed these expressions in sufficient detail to do so, we consider the calculation of value-at-risk and expected shortfall in these two models

Comparative evaluation of pyrethroid insecticide formulations against Triatoma infestans (Klug): residual efficacy on four substrates

We investigated the residual efficacy of four insecticide formulations used in Chagas disease vector control campaigns: cyfluthrin 12.5% suspension concentrace (SC), lambda- cyhalothrin 10% wettable powder (WP), deltamethrin 2.5% SC, and 2.5% WP on four types of circular blocks of wood, straw with mud, straw with mud painted with lime, and mud containing 5% of cement. Three concentrations of these insecticides were tested: the LC90 (previously determined on filter paper), the double of the LC90, and the recommended operational dose. For each bioassay test, 15 third-stage nymphs of Triatoma infestans (Klug) (Hemiptera: Reduviidae) were exposed for 120 h to each treatment at 24 h, 30, 60, 90, and 180 days post-spraying. Mortality rates, moulting history and behaviour were recorded at 24, 48, 72, and 120 h of exposure. Mortality rates were highest during the first 30 days post-spraying. Highest mortality rates (above 50%) were observed for deltamethrin 2.5% SC and lambda-cyhalothrin 10% WP on wood blocks up to three months post-spraying. Mud was the substrate on which treatments showed lowest persistence, with the other two substrates showing intermediate residual efficacy of all treatments. During the first 30 days WP formulations were not as effective as SC flowable formulations but, overall in the longer term, WP gave grater mortality rates of T. infestans nymphs exposed at up to six months post-spraying. Porous surfaces, especially mud, showed most variability presumably due to absorption of the insecticide. In contrast the less porous surfaces (i.e. wood and lime-coated mud) kept mortality rates high for longer post-treatment, irrespective of the insecticide concentration used

Clinical and cost-effectiveness analysis of an open label, single-centre, randomised trial of spinal cord stimulation (SCS) versus percutaneous myocardial laser revascularisation (PMR) in patients with refractory angina pectoris: The SPiRiT trial.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Patients with refractory angina have significant morbidity. This study aimed to compare two of the treatment options, Spinal Cord Stimulation (SCS) and Percutaneous Myocardial Laser Revascularisation (PMR) in terms of clinical outcomes and cost-effectiveness. METHODS: Eligible patients were randomised to PMR or SCS and followed up for exercise tolerance time (ETT), Canadian Cardiovascular Society (CCS) classification and the quality of life measures SF-36, Seattle Angina Questionnaire and the EuroQoL at 3, 12 and 24 months. Utilities were calculated using the EQ-5D and these and costs were compared between groups. The incremental cost-effectiveness ratio (ICER) per QALY for SCS compared to PMR was also calculated. RESULTS: At 24 months post-randomisation, patients that had SCS and PMR had similar ETT (mean difference 0.05, 95% CI -2.08, 2.18, p = 0.96) and there was no difference in CCS classification or quality of life outcomes. The difference in overall mean costs when comparing SCS to PMR was GBP5,520 (95% CI GBP1,966 to GBP8,613; p < 0.01) and the ICER of using SCS was GBP46,000 per QALY. CONCLUSION: Outcomes after SCS did not differ appreciably from those after PMR, with the former procedure being less cost-effective as currently applied. Larger studies could clarify which patients would most benefit from SCS, potentially increasing cost-effectiveness. TRIAL REGISTRATION: Current Controlled Trials ISRCTN09648950.Published versio

The impact of semi-natural broadleaf woodland and pasture on soil properties and flood discharge

Woodlands can reduce the risk of rainfall-generated flooding through increased interception, soil infiltration and available storage. Despite growing evidence, there is still low confidence in using woodlands as a flood mitigation method due to limited empirical data, particularly for broadleaf woodlands. We measured soil properties and streamflow for nine small (<0.2 km2) upland catchments and compared mature semi-natural broadleaf woodland where no stock grazing occurs to pasture with varied grazing intensity. We compared streamflow across 28 storm events including a 1 in 10-year event, two 1 in 4-year events and five 1 in 1.5-year events, identified over a 13-month period. We found that semi-natural broadleaf woodlands reduce specific peak discharge by 23%–60% and peak runoff coefficients by 30%–60% compared with pasture. Response to storm events took 14–50% longer in woodland compared to pasture. These differences in flood response are partly explained by more permeable woodland soils, 11–20 times greater than pasture soil. The more muted response of wooded catchments to storm events is consistent across the storms investigated, including Storm Ciara, a 1 in 10-year event. Our analysis strengthens the argument that semi-natural woodlands can reduce rainfall-generated flooding contributing to the evidence base for natural flood management

Window screening, ceilings and closed eaves as sustainable ways to control malaria in Dar es Salaam, Tanzania.

BACKGROUND\ud \ud Malaria transmission in Africa occurs predominantly inside houses where the primary vectors prefer to feed. Human preference and investment in blocking of specific entry points for mosquitoes into houses was evaluated and compared with known entry point preferences of the mosquitoes themselves.\ud \ud METHODS\ud \ud Cross-sectional household surveys were conducted in urban Dar es Salaam, Tanzania to estimate usage levels of available options for house proofing against mosquito entry, namely window screens, ceilings and blocking of eaves. These surveys also enabled evaluation of household expenditure on screens and ceilings and the motivation behind their installation.\ud \ud RESULTS\ud \ud Over three quarters (82.8%) of the 579 houses surveyed in Dar es Salaam had window screens, while almost half (48.9%) had ceilings. Prevention of mosquito entry was cited as a reason for installation of window screens and ceilings by 91.4% (394/431) and 55.7% (127/228) of respondents, respectively, but prevention of malaria was rarely cited (4.3%, 22/508). The median cost of window screens was between US $21-30 while that of ceilings was between US$301-400. The market value of insecticide-treated nets, window screening and ceilings currently in use in the city was estimated as 2, 5 and 42 million US$. More than three quarters of the respondents that lacked them said it was too expensive to install ceilings (82.2%) or window screens (75.5%).\ud \ud CONCLUSION\ud \ud High coverage and spending on screens and ceilings implies that these techniques are highly acceptable and excellent uptake can be achieved in urban settings like Dar es Salaam. Effective models for promotion and subsidization should be developed and evaluated, particularly for installation of ceilings that prevent entry via the eaves, which are the most important entry point for mosquitoes that cause malaria, a variety of neglected tropical diseases and the nuisance which motivates uptake

Care of elderly in Portugal: Official data and scientific and professional challenges

First published online: 10 August 2019The world has never been so active in approaching human needs and human rights. As the population has become older, new kind of pressures has been made over health and protective services, as well as on research targeted to older adults. This chapter presents the scientific and practical developments in the field of elder mistreatment in Portugal. An overview of the scientific trends in Portuguese research is presented. National research on elder mistreatment has been increasing slowly. The current national scenery is focused on prevalence data and identifying risk and vulnerabilities. This chapter will also discuss the support structures available for mistreated older adults in Portugal, namely the current legal framework and the institutions/entities that offer aid to the victims. Legally, elder mistreatment in Portugal is no different from domestic violence, though some legislative advances have been seen in abandonment. Some structures have been developed over the years to offer aid to older adults, from special programs in the police to private institutions, passing by government supported initiatives.This study was conducted at Psychology Research Centre (UID/PSI/01662/2013), University of Minho, and supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education through national funds and co-financed by FEDER through COMPETE2020 under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007653). The first author was funded by a scholarship from the Portuguese Foundations for Science and Technology - FCT - (PD/BD/105965/2014

An open-label phase II study of low-dose thalidomide in androgen-independent prostate cancer

The antiangiogenic effects of thalidomide have been assessed in clinical trials in patients with various solid and haematological malignancies. Thalidomide blocks the activity of angiogenic agents including bFGF, VEGF and IL-6. We undertook an open-label study using thalidomide 100 mg once daily for up to 6 months in 20 men with androgen-independent prostate cancer. The mean time of study was 109 days (median 107, range 4–184 days). Patients underwent regular measurement of prostate-specific antigen (PSA), urea and electrolytes, serum bFGF and VEGF. Three men (15%) showed a decline in serum PSA of at least 50%, sustained throughout treatment. Of 16 men treated for at least 2 months, six (37.5%) showed a fall in absolute PSA by a median of 48%. Increasing levels of serum bFGF and VEGF were associated with progressive disease; five of six men who demonstrated a fall in PSA also showed a decline in bFGF and VEGF levels, and three of four men with a rising PSA showed an increase in both growth factors. Adverse effects included constipation, morning drowsiness, dizziness and rash, and resulted in withdrawal from the study by three men. Evidence of peripheral sensory neuropathy was found in nine of 13 men before treatment. In the seven men who completed six months on thalidomide, subclinical evidence of peripheral neuropathy was found in four before treatment, but in all seven at repeat testing. The findings indicate that thalidomide may be an option for patients who have failed other forms of therapy, provided close follow-up is maintained for development of peripheral neuropathy