2,436 research outputs found

    An Analysis of Cost Premiums and Losses Associated with USAF Military Construction (MILCON)

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    Military construction (MILCON) represents 40% of the federal government\u27s 30billionconstructionbudget.Thefederalbudgetisfixed;therefore,anycostoverageslikelyaffectprojectscopeorrequirements.ThisstudyinvestigatedifMILCONprocurementcostsmorethanprivateindustryconstructionandifso,whatcausesthecostpremiums.Acombinationofindepthliteraturereview,expertinterviews,auniquecasestudy,expertsurveys,andgeospatialstatisticalanalysisansweredtheresearchquestion.ThecasestudyevaluatedtwonearlyidenticalprojectstodeterminehowinternalfactorsaffectMILCONcostpremiums.ThisstudyconfirmedtheexistenceofMILCONcostpremiums.Additionally,11majorcostpremiumthemesemerged:overlyrestrictivestatementsofrequirements,failingtobalancerisk,stiflingornotapplyinginnovation,uniqueMILCONrequirements,parameterizationoftheexecutionprocess,selectionofconstructionspecifications,scheduleandsubmittalpolicies,perceptionofMILCONconstructionagents,antiterrorism/forceprotectionrequirements,FederalAcquisitionRegulations,andsocioeconomiclawsandpolicies.Additionally,inspiteofcontractrequirementsimilarities,thestudiedprojectsdifferedbyoverayearofconstructiontimeand30 billion construction budget. The federal budget is fixed; therefore, any cost overages likely affect project scope or requirements. This study investigated if MILCON procurement costs more than private industry construction and if so, what causes the cost premiums. A combination of in-depth literature review, expert interviews, a unique case study, expert surveys, and geospatial statistical analysis answered the research question. The case study evaluated two nearly identical projects to determine how internal factors affect MILCON cost premiums. This study confirmed the existence of MILCON cost premiums. Additionally, 11 major cost premium themes emerged: overly restrictive statements of requirements, failing to balance risk, stifling or not applying innovation, unique MILCON requirements, parameterization of the execution process, selection of construction specifications, schedule and submittal policies, perception of MILCON construction agents, anti-terrorism/force protection requirements, Federal Acquisition Regulations, and socioeconomic laws and policies. Additionally, in spite of contract requirement similarities, the studied projects differed by over a year of construction time and 7 million. Research frequently cites federal laws and policies as the primary cost premium driver; however, this research demonstrated internal construction policies, which the military can control, also cause increased cost premiums

    Transpolar arc evolution and associated potential patterns

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    International audienceWe present two event studies encompassing detailed relationships between plasma convection, field-aligned current, auroral emission, and particle precipitation boundaries. We illustrate the influence of the Interplanetary Magnetic Field By component on theta aurora development by showing two events during which the theta originates on both the dawn and dusk sides of the auroral oval. Both theta then move across the entire polar region and become part of the opposite side of the auroral oval. Electric and magnetic field and precipitating particle data are provided by DMSP, while the Polar UVI instrument provides measurements of auroral emissions. Utilizing satellite data as inputs, the Royal Institute of Technology model provides the high-latitude ionospheric electrostatic potential pattern calculated at different times during the evolution of the theta aurora, resulting from a variety of field-aligned current configurations associated with the changing global aurora. Key words. Ionosphere (auroral ionosphere; electric fields and currents). Magnetospheric physics (magnetosphereionosphere interactions

    PROPHECY—a database for high-resolution phenomics

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    The rapid recent evolution of the field phenomics—the genome-wide study of gene dispensability by quantitative analysis of phenotypes—has resulted in an increasing demand for new data analysis and visualization tools. Following the introduction of a novel approach for precise, genome-wide quantification of gene dispensability in Saccharomyces cerevisiae we here announce a public resource for mining, filtering and visualizing phenotypic data—the PROPHECY database. PROPHECY is designed to allow easy and flexible access to physiologically relevant quantitative data for the growth behaviour of mutant strains in the yeast deletion collection during conditions of environmental challenges. PROPHECY is publicly accessible at http://prophecy.lundberg.gu.se

    Astrid-2, an advanced microsatellite for auroral research

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    International audienceThe successful launch of the Swedish microsatellite Astrid-2 in December 1998 began a new era of auroral research, with advanced microprobes of 30 kg or less used as research tools. Innovative technologies and low-mass solutions were used for the sensors and deployment systems to allow a fairly complete set of scientific instruments within the 10 kg allocated for the scientific payload. A newly developed wire boom deployment system proved to function excellently. During its seven month lifetime Astrid-2 collected more than 26 Gbytes of high-quality data of auroral electric and magnetic fields, and auroral particle and plasma characteristics from approximately 3000 orbits at an inclination of 83° and an altitude of about 1000 km. Scientific results cover a broad range of topics, from the physics of energization of auroral particles to how the magnetosphere responds to the energy input from the solar wind and global magnetic field modelling. The fulfilment of both the technological and the scientific mission objectives has opened entirely new possibilities to carry out low-budget multipoint measurements in near-Earth space

    The Perfect Law of Liberty on Poverty and Wealth: A Precursor to Paul?

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    Even as other tensions are resolved, some scholars continue to pit James against Paul with respect to their views on poverty and wealth. This paper first summarises the main contributions of James to the topic. Then it asks how far back in the letter-writing ministry of Paul can parallels to James be found. Recognizing that relative chronologies usually remain unaltered even if the deutero-Paulines are deemed pseudonymous, the survey looks at the key texts in the Pastorals, the Prison Epistles, 1–2 Corinthians and Romans, the Thessalonian letters and Galatians. It finds the most striking and informative parallel at the earliest point in the sequence, in Galatians 2:10. While acknowledging other possibilities, the study suggests that the most natural source for most of Paul’s teaching on poverty and wealth is, or is mediated by, James. The two authors also agree on what may be the unifying theme of New Testament theology – fulfilment of the Law – expressed in both of these writers particularly in the command to love one’s neighbour, which directly affects matters of care for the impoverished. A wedge should not be inserted between Paul and James on poverty and wealth; rather, they demonstrate striking similarities

    Iterative approach to computational enzyme design

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    A general approach for the computational design of enzymes to catalyze arbitrary reactions is a goal at the forefront of the field of protein design. Recently, computationally designed enzymes have been produced for three chemical reactions through the synthesis and screening of a large number of variants. Here, we present an iterative approach that has led to the development of the most catalytically efficient computationally designed enzyme for the Kemp elimination to date. Previously established computational techniques were used to generate an initial design, HG-1, which was catalytically inactive. Analysis of HG-1 with molecular dynamics simulations (MD) and X-ray crystallography indicated that the inactivity might be due to bound waters and high flexibility of residues within the active site. This analysis guided changes to our design procedure, moved the design deeper into the interior of the protein, and resulted in an active Kemp eliminase, HG-2. The cocrystal structure of this enzyme with a transition state analog (TSA) revealed that the TSA was bound in the active site, interacted with the intended catalytic base in a catalytically relevant manner, but was flipped relative to the design model. MD analysis of HG-2 led to an additional point mutation, HG-3, that produced a further threefold improvement in activity. This iterative approach to computational enzyme design, including detailed MD and structural analysis of both active and inactive designs, promises a more complete understanding of the underlying principles of enzymatic catalysis and furthers progress toward reliably producing active enzymes

    The biology of an isolated population of the American Flamingo Phoenicopterus ruber in the Galapagos Islands

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    A genetically and morphologically divergent population of c. 500 American Flamingos, isolated from the parental Caribbean stock of Phoenicopterus ruber, occurs in the Galapagos archipelago. Based primarily on data from a 3-year study, we provide the first description of the feeding and breeding biology of this population. Galapagos provides a suitable habitat comprising lagoons on a number of islands, among which the flamingos travel in response to food and nest site availability. We identify putative food items. The occurrence and quantity of some food species was associated with the chlorosity of lagoon water, as was the distribution of flamingos. The flamingos bred opportunistically at five lagoons on four islands, sometimes simultaneously on more than one island. Group display usually involved = 20 birds, and colonies contained as few as three nests. Laying occurred during nine months of the year, mainly August–January, coinciding with the coastal drier season and low lagoon water levels. On average c.30% of all adults incubated clutches each year, producing 0.37 fledglings per clutch. Recruitment is probably sufficient to sustain the population, which has been stable over at least c. 45 years, and is probably limited by suitable habitat. Moult to flightlessness was recorded among adults. We review potential dangers to this unique population and suggest conservation measures

    Mechanisms for Decreased Function of B Cells in Aged Mice and Humans

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    Abstract The immune system has been known for some time to be compromised in aged individuals, e.g., both mice and humans, and in both humoral and cellular responses. Our studies have begun to elucidate intrinsic B lymphocyte defects in Ig class switch recombination, activation-induced cytidine deaminase, and E47 transcription factor expression. These defects occur in both mice and humans. Our studies have also shown that tristetraprolin is one of the key players in regulating the decreased E47 mRNA stability in aged B lymphocytes. These and current studies should lead to improvements in B lymphocyte function in aged populations
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