A software reliability model based on a geometric sequence of failure rates

Software reliability models are an important tool in quality management and release planning. There is a large number of different models that often exhibit strengths in different areas. This paper proposes a model that is based on a geometric sequence (or progression) of the failure rates of faults. This property of the failure process was observed in practice at Siemens among others and led to the development of the proposed model. It is described in detail and evaluated using standard criteria. Most importantly, the model performs constantly well over several projects in terms of its predictive validity

An enrichment method for temperature-sensitive and auxotrophic mutants of yeast

An enrichment procedure that exploits the difference in heat-sensitivity between exponentially growing and stationary phase cells has been developed for the isolation of yeast mutants. Enrichments of up to 12-fold for temperature-sensitive lethal mutants and of up to 15-fold for auxotrophs have been obtained with single cycles of selection. Still higher enrichments (to frequencies of greater than 90% and 80% for temperature-sensitive lethals and auxotrophs, respectively) have been obtained with multiple cycles of selection. The method requires no special parent strain, and seems adaptable to the selection of a wide variety of types of mutants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47545/1/438_2004_Article_BF00274022.pd

IUCN UK Commission of Inquiry on Peatlands.

Peatlands are areas of land with a naturally accumulated layer of peat. These are formed under waterlogged conditions from carbon rich, dead and decaying plant material. In the UK mosses, mainly Sphagnum species, are the main formers of peat. Peatlands are found in at least 175 countries – from the tropics to the poles – and cover around 4 million km2 or 3% of the world’s land area. In Europe, peatlands extend to ca. 515,000 km2 . The UK is amongst the top ten nations of the world in terms of its total peatland area. The UK has between 9-15% of Europe’s peatland area (46,000-77,000 km2 ) and about 13% of the world’s blanket bog – one of the world’s rarest habitats. There are three main types of peatland in the UK: blanket bogs, raised bogs and fens. The international importance of the peatlands found in the UK give it an especial responsibility for their management and conservation. The IUCN UK Commission of Inquiry on Peatlands has gathered up-to-date knowledge from science, policy and practice. The assessment focuses on blanket bog and raised bog peatlands, because they represent over 95% of all UK peatland habitat and offer an opportunity to make early and substantial progress in delivering a combination of economic, social and biodiversity gains. However, we recognise that lowland, river and groundwater-fed fen peatlands are also vital carbon stores, as well as existing and potential areas of rich biodiversity, which have also been subject to intensive and damaging management. Fen peatlands share many of the issues affecting rain-fed peatlands but with distinct differences in terms of their functions, threats and pressures, which merit further investigation. A multidisciplinary team of experts produced this Report. It provides an authoritative assessment of the available evidence, based on peer-reviewed scientific consensus about the state of peatlands, the impacts of different activities on peatland ecosystems and the services they provide and the benefits of restoring and conserving them. The assessment explores mechanisms and processes for peatland conservation action, recognising the different social, economic and environmental drivers. The evidence-gathering approach was inclusive, engaging individual land managers as well as a wide range of organisations, which in itself has helped to foster joint action for peatland conservation and restoration. The Assessment Report sets out the main conclusions, highlighting gaps and opportunities for further action. It identifies ways to secure additional funding and develop expertise to help land managers restore the UK’s peatlands and to allow decision makers to take better account of their multiple benefits

Curious bivalves: Systematic utility and unusual properties of anomalodesmatan mitochondrial genomes

publisher: Elsevier articletitle: Curious bivalves: Systematic utility and unusual properties of anomalodesmatan mitochondrial genomes journaltitle: Molecular Phylogenetics and Evolution articlelink: http://dx.doi.org/10.1016/j.ympev.2017.03.004 content_type: article copyright: Crown Copyright © 2017 Published by Elsevier Inc. All rights reserved.The file attached is the final draft version of the article

Factor VIII - phospholipid mixtures and factor VIII inhibitors Studies in haemophilic dogs

SIGLEAvailable from British Library Document Supply Centre- DSC:D60079 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Role of chronic disseminated intravascular coagulation in a case of canine angiostrongylosis

A dog whose major clinical signs suggested a coagulopathy, is described. The dog had a history of bleeding episodes and had a severe regenerative anaemia. By using specific factor assays, the coagulopathy was found to be due to a consumptive intravascular process that resembled chronic disseminated intravascular coagulation. Subsequent investigations identified Angiostrongylus vasorum as the cause

Have You Heard?

In the era of ‘fake news’ it is becoming ever more difficult for the public to separate exaggeration from facts. Additionally, many engagement activities target school-aged children and/or are held in spaces that may be a barrier for diverse adult participation. The Have You Heard? project intends to flip this script. Since 2017 we have delivered events in existing community spaces to open up the conversation between scientists and members of the public who don’t have the opportunity to visit science events. The challenges, successes and future plans of this project will be shared at this poster

Security vulnerabilities in software systems: A quantitative perspective

Abstract. Security and reliability are important attributes of complex software systems. It is now common to use quantitative methods for evaluating and managing reliability. In this work we examine the feasibility of quantitatively characterizing some aspects of security.In particular, we investigate if it is possible to predict the number of vulnerabilities that can potentially be identified in a future release of a software system. We use several major operating systems as representatives of complex software systems. The data on vulnerabilities discovered in some of the popular operating systems is analyzed. We examine this data to determine if the density of vulnerabilities in a program is a useful measure. We try to identify what fraction of software defects are security related, i.e., are vulnerabilities. We examine the dynamics of vulnerability discovery hypothesizing that it may lead us to an estimate of the magnitude of the undiscovered vulnerabilities still present in the system. We consider the vulnerability-discovery rate to see if models can be developed to project future trends. Finally, we use the data for both commercial and open-source systems to determine whether the key observations are generally applicable. Our results indicate that the values of vulnerability densities fall within a range of values, just like the commonly used measure of defect density for general defects. Our examination also reveals that vulnerability discovery may be influenced by several factors including sharing of codes between successive versions of a software system.