332 research outputs found
Galaxy surface photometry
We describe galaxy surface photometry based on fitting ellipses to the
isophotes of the galaxies. Example galaxies with different isophotal shapes are
used to illustrate the process, including how the deviations from elliptical
isophotes are quantified using Fourier expansions. We show how the definitions
of the Fourier coefficients employed by different authors are linked. As
examples of applications of surface photometry we discuss the determination of
the relative disk luminosities and the inclinations for E and S0 galaxies. We
also describe the color-magnitude and color-color relations. When using both
near-infrared and optical photometry, the age-metallicity degeneracy may be
broken. Finally we discuss the Fundamental Plane where surface photometry is
combined with spectroscopy. It is shown how the FP can be used as a sensitive
tool to study galaxy evolution.Comment: 40 pages. Lectures given at the Nordic-Baltic Research Course in
Applied Astrophysical Photometry, held September 1999 at the Moletai
Observatory, Lithuania. Baltic Astronomy, 8, 535 (1999), in press. Note the
year. The paper with Fig. 2, 14 and 15 in original (high) resolution is
available at http://www.astro.ku.dk/~milvang/papers/BA_MJ_J.ps.gz or
http://www.gemini.edu/documentation/preprints/pre58.htm
Investigating the integration of design and construction from a lean perspective
Purpose â Better integration of project processes has often been identified as the key issue regarding construction performance improvement. In some countries lean construction has become well-established, although there appears to be considerable diversity in the interpretation of the concept. Lean construction initially focused on production aspects, but gradually design issues have started to receive more attention and integrating construction design and production processes from a lean perspective are beginning to be addressed. The purpose of this paper is to identify some of the practical challenges underlying the implementation of approaches promoted as âleanâ and compare this with published research/theory.
Design/methodology/approach â Following an extensive review of the literature, a multiple case-strategy approach was used to explore the practical application of lean approaches to design and construction integration in an organisational setting. Summaries of the case studies, one from the USA and two from Denmark, help to highlight a number of pertinent issues facing practitioners and researchers.
Findings â Findings suggest that it is possible to identify a number of aspects that (in theory as well as in practice) both influence and, to various extents, limit the applicability of the lean philosophy to construction. Findings also help to emphasise the importance of a number of interdependent factors for achieving better integration, namely: value identification/specification; an appropriate project delivery framework; structuring and planning of delivery processes; transparency; management and leadership; learning; and the importance of local context.
Originality/value â The findings provide an original contribution to the integration of design and construction activities from a lean perspective. The findings are generic and could be practically applied in a variety of contexts
Lost in transition: the transfer of lean manufacturing to construction
Purpose - The purpose of this paper is to explore the transfer of lean manufacturing/production from the Japanese manufacturing industry to the construction sector in the west. Design/methodology/approach - Research literature from the fields of lean manufacturing/production and lean construction was reviewed. This revealed a number of characteristics that are specific to lean construction, most notably the recognition that critical research findings have been slow to emerge but appear to be gaining momentum. Findings - In the transition from manufacturing to construction the process losses appear to be related to critical aspects and the challenges surrounding practical application to a different context. Lean is highly interpretive and there is no shared definition or understanding of what is meant by lean, lean production, and lean construction. The focus has been mainly on production system design, planning and management, and implementation. This narrow focus has meant that some important issues concerning the wider aspects of lean have been overlooked. There is a need for a "back to basics" discussion on many other aspects of the approach, such as whole-life value and waste identification. Research limitations/implications - The work is limited to an extensive literature review. Originality/value - The extensive literature review makes an original contribution to the lean construction field and provides a valuable resource for researchers
The Informativeness of Estimation Moments
This paper introduces measures for how each moment contributes to the
precision of parameter estimates in GMM settings. For example, one of the
measures asks what would happen to the variance of the parameter estimates if a
particular moment was dropped from the estimation. The measures are all easy to
compute. We illustrate the usefulness of the measures through two simple
examples as well as an application to a model of joint retirement planning of
couples. We estimate the model using the UK-BHPS, and we find evidence of
complementarities in leisure. Our sensitivity measures illustrate that the
estimate of the complementarity is primarily informed by the distribution of
differences in planned retirement dates. The estimated econometric model can be
interpreted as a bivariate ordered choice model that allows for simultaneity.
This makes the model potentially useful in other applications
Sediment oxygen consumption: Role in the global marine carbon cycle
The seabed plays a key role in the marine carbon cycle as a) the terminal location of aerobic oxidation of organic matter, b) the greatest anaerobic bioreactor, and c) the greatest repository for reactive organic carbon on Earth. We compiled data on the oxygen uptake of marine sediments with the objective to understand the constraints on mineralization rates of deposited organic matter and their relation to key environmental parameters. The compiled database includes nearly 4000 O 2 uptake data and is available as supplementary material. It includes also information on bottom water O 2 concentration, O 2 penetration depth, geographic position, water depth, and full information on the data sources. We present the different in situ and ex situ approaches to measure the total oxygen uptake (TOU) and the diffusive oxygen uptake (DOU) of sediments and discuss their robustness towards methodological errors and statistical uncertainty. We discuss O 2 transport through the benthic and diffusive boundary layers, the diffusion- and fauna-mediated O 2 uptake, and the coupling of aerobic respiration to anaerobic processes. Five regional examples are presented to illustrate the diversity of the seabed: Eutrophic seas, oxygen minimum zones, abyssal plains, mid-oceanic gyres, and hadal trenches. A multiple correlation analysis shows that seabed O 2 uptake is primarily controlled by ocean depth and sea surface primary productivity. The O2 penetration depth scales with the DOU according to a power law that breaks down under the abyssal ocean gyres. The developed multiple correlation model was used to draw a global map of seabed O2 uptake rates. Respiratory coefficients, differentiated for depth regions of the ocean, were used to convert the global O 2 uptake to organic carbon oxidation. The resulting global budget shows an oxidation of 212 Tmol C yr â 1 in marine sediments with a 5-95% confidence interval of 175-260 Tmol C yr â 1 . A comparison with the global flux of particulate organic carbon (POC) from photic surface waters to the deep sea, determined from multiple sediment trap studies, suggests a deficit in the sedimentation flux at 2000 m water depth of about 70% relative to the carbon turnover in the underlying seabed. At the ocean margins, the flux of organic carbon from rivers and from vegetated coastal ecosystems contributes greatly to the budget and may even exceed the phytoplankton production on the inner continental shelf
Biogeochemie, Fluide, Gashydrate und PalĂ€oklima des Schwarzen Meers = Biogeochemistry, fluids, gas hydrates and paleo climate of the Black Sea : Istanbul, Trabzon, Istanbul ; Forschungsschiff Meteor, Reise Nr. M72 ; 07.02.2007 â 04.06.2007
Das Schwarze Meer ist das gröĂte anoxische Meeresbecken der Erde. Hohe biologische Produktion in der Deckschicht und ein tiefer anoxischer Wasserkörper unterhalb der Chemokline in 100-150 m Wassertiefe fĂŒh-ren zu einzigartigen Bedingungen fĂŒr mikrobielles Leben, geochemische Kreis-lĂ€ufe und Sedimentationsprozesse. Gas- und Fluidemissionen aus verschiedenen geolo-gischen Formationen wie z.B. Methanaus-tritt entlang der Schelfkante oder AusstoĂ von kohlenwasserstoffhaltigen Fluiden aus Schlammvulkanen in Tiefseeregionen lie-fern ein einzigartiges Umfeld fĂŒr die Erfor-schung von geologischen Tiefenprozessen, geochemischen KreislĂ€ufen, mikrobiellen Habitaten und den kontrollierenden Bedin-gungen fĂŒr mikrobielle SchlĂŒsselprozesse der ElementkreislĂ€ufe in einer permanent anoxischen Welt. Fahrtabschnitt M72/1 untersucht unter der Leitung von Dr. R. Seifert geochemische KreislĂ€ufe und mikrobielles Leben an akti-ven Gasquellen innerhalb der StatbilitĂ€ts-zone von Gashydrat ab ca. 700 m Wasser-tiefe im PalĂ€o-Djnepr-Gebiet. Der anschlie-Ăende Fahrtabschnitt M 72/2 findet im Rahmen des EU-Projekts HERMES und des deutschen Geotechnologien-Projekts MUMM II unter der Leitung von Prof. Dr. A. Boetius statt und untersucht die Kontrol-len und Mechanismen der mikrobiellen Transporte und UmsĂ€tze chemischer Ele-mente an Methanquellen auf der Schelfkante und an Fluidaustritten von Schlammvulka-nen. Als AktivitĂ€t eines weiteren Geotech-nologienprojekts METRO widmet sich Fahrtabschnitt M 72/3 unter der Leitung von Prof. Dr. G. Bohrmann der Erforschung von Herkunft, Verteilung und Dynamik von Methan und Gashydraten in Sedimenten sowie der Untersuchung von MethanflĂŒssen von den Sedimenten in die WassersĂ€ule. AnschlieĂend wird Fahrtabschnitt M 72/4seismische Untersuchungen der Migrationswege von Fluiden in den tiefen Unter-grĂŒnden des Djnepr-seep-Systems und der Schlammvulkane im Sorokin Trog unter der Leitung von Dr. J. Bialas vornehmen. Den Abschluss bildet Fahrtabschnitt M 72/5 un-ter der Leitung von Dr. C. Borowski mit Untersuchungen der geochemischen und mikrobiellen Prozesse in der geschichteten WassersĂ€ule und in Sedimenten um die Chemokline wie in den tiefen anoxischen Becken. Die Reise M 72 wird am 07. Februar 2007 in Istanbul (TĂŒrkei) beginnen und am 04. Juni 2007 ebenfalls in Istanbul enden.The Black Sea is the largest anoxic basin on earth. High biological productivity in the oxygenated surface waters and a deep anoxic water body below the chemocline at 100â150 m water depth provide unique conditions for anaerobic microbial life, geochemical cycling and sedimentation processes which make the present day Black Sea a modern type locality for TOC-rich sedimentation and element cycling processes in the geological past. Hydrocarbon emissions from various geological settings such as methane gas seepage along large stretches of the shelf break and fluid discharges from mud volcanoes in deep-sea regions provide unique environmental conditions for studying geological subsurface processes, geochemical cycling, microbial habitats and controls on microbial key processes for element cycling in a permanent anoxic world. Geochemical cycling and microbial life at active gas seeps located in the stability zone of gas hydrates below 700 m water depth in the paleo Dnepr area will be investigated by leg M 72/1 with Dr. R. Seifert as a chief scientist. In the frame of the EU project HERMES and the German âGeotechnologiesâ project MUMM II, leg M 72/2 with Prof. Dr. A. Boetius as a chief scientist will focus on the controls and mechanisms of chemical element transport and breakdown by seep microbiota at shelf break gas seeps and fluid discharges of mudvolcanoes in the Sorokin Trough. As an activity of another âGeotechnologiesâ project METRO, leg M 72/3 with Prof. Dr. G. Bohrmann as a chief scientist will study in various geological settings, mainly of the eastern Black Sea, the origins, distributions and dynamics of methane and gas hydrates in sediments and also methane fluxes from the sediment to the water column. This will be followed by seismic investigations of fluid migration pathways in the subsurface of Sorokin Trough mud volcanoes and the paleo-Dnepr seepage system during M 72/4 with Dr. J. Bialas as a chief scientist. The final leg M 72/5 with Dr. C. Borowski as a chief scientist will lead to various areas in the western and eastern Black Sea and will focus on geochemical and microbiological processes in the stratified water column and in sediments around the chemocline and in the anoxic basins. Cruise M 72 will start on 07th February in Istanbul (Turkey) and end on 04th June again in Istanbul
Forschungsschiff / Research Vessel METEOR Reise Nr. 72 / Cruise No. 72 07. 02. 2007 â 04. 06. 2007 Biogeochemie, Fluide, Gashydrate und PalĂ€oklima des Schwarzen Meers = Biogeochemistry, fluids, gas hydrates and paleo climate of the Black Sea Istanbul â Trabzon - Istanbul
Inter-population variations in concentrations, determinants of and correlations between 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE): a cross-sectional study of 3161 men and women from Inuit and European populations.
The study is part of a collaborative project (Inuendo), aiming to assess the impact of dietary persistent organochlorine pollutants (POPs) on human fertility. The aims with the present study are to analyze inter-population variations in serum concentrations of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE), to assess inter-population variations in biomarker correlations, and to evaluate the relative impact of different determinants for the inter-individual variations in POP-biomarkers. CB-153 concentrations were much higher in Inuits and Swedish fishermen's populations than in the populations from Eastern Europe, whereas the pattern was different for p,p'-DDE showing highest concentrations in the Kharkiv population. The correlations between the POP-biomarkers varied considerably between the populations, underlining that exposure sources differ and that the choice of representative biomarkers of overall POP exposure has to be based on an analysis of the specific exposure situation for each population. Age and gender were consistent determinants of serum POPs; seafood was of importance only in the Inuit and Swedish populations
Endoscopic and Histopathologic Predictors of Recurrence of Colorectal Adenoma on Lowering the Miss Rate
Bone Mineral Density is an Independent Determinant of Left Ventricular Mass Index in the General Female Population
Background and Objectives: Left ventricular hypertrophy (LVH) is a well known cardiovascular prognostic predictor. Osteoporosis has been suggested to be associated with cardiovascular disease. According to studies of primary hyperparathyroidism, a pathophysiological association between calcium metabolism and LVH has been suggested but is not yet fully understood. This study was performed to investigate the association between bone mineral density (BMD) and left ventricular mass index (LVMI) in a general population. Subjects and Methods: Data from 460 subjects among 543 subjects sampled from a general population in a rural area in Korea were analyzed. BMD, echocardiography, brachial-ankle pulse wave velocity (baPWV), carotid intima-media thickness (IMT) measurement as well as the measurements of blood pressure, blood chemistry and metabolic parameters were analyzed. BMD was measured using the Sahara Clinical Bone Sonometer (Hologic Inc., Mass., USA). Results: Age of the subjects was 59.4??12.4 years. Males were 42.2% (n=194). In a simple correlation analysis on female subjects, age and waist circumference showed negative correlation, and body mass index (BMI) showed positive correlation with BMD. However, only age showed negative correlation with BMD in male subjects. After adjusting baPWV and carotid IMT, we found that BMD was an independent determinant of LVMI in female subjects (??=-13.703, p=0.016), but not in male subjects (??=-1.235, p=0.841). Conclusion: BMD is a consistent and independent determining factor of LVMI, BMI and carotid IMT in postmenopausal women. Copyright ?? 2010 The Korean Society of Cardiology
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