Esta tese, de caráter metodológico, é uma proposta de análise econômica de projetos de petróleo com emprego de cópulas e processos estocásticos autorregressivos envolvendo cinco variáveis fundamentais: o preço da commodity, a taxa mínima de atratividade (TMA), o custo de investimento (CAPEX), o custo operacional (OPEX) e a curva de produção de óleo. A premissa é a existência de uma estratégia de produção já estabelecida, de preferência decorrente de metodologias validadas em simulação numérica de reservatórios. O fluxo de caixa do projeto é baseado numa formulação simplificada de VPL e num modelo analítico de produção condicionado à referida estratégia. Para a aplicação desta metodologia são estimados modelos da família GARCH e ARMA para o preço do óleo e TMA, cópulas Arquimedianas para o CAPEX e o OPEX e cópulas elípticas para as variáveis que compõem a curva analítica de produção. Uma solução computacional, desenvolvida para a validação desta tese, possibilita não só a estimativa dos modelos como a incorporação destes no fluxo de caixa de um projeto de petróleo, tanto em regime de concessão como de partilha de produção. A matriz de incertezas combina os atributos preço e taxa para três cenários econômicos...
The goal of this project was to determine the relative refractive index (RI) of the interior of multilamellar bodies (MLBs) compared to the adjacent cytoplasm within human nuclear fiber cells. MLBs have been characterized previously as 1-4 μm diameter spherical particles covered by multiple lipid bilayers surrounding a cytoplasmic core of variable density. Age-related nuclear cataracts have more MLBs than transparent donor lenses and were predicted to have high forward scattering according to Mie scattering theory, assuming different RIs for the MLB and cytoplasm. In this study quantitative values of relative RI were determined from specific MLBs in electron micrographs of thin sections and used to calculate new Mie scattering plots. Fresh lenses were Vibratome sectioned, immersion fixed and en bloc stained with osmium tetroxide and uranyl acetate, or uranyl acetate alone, prior to dehydration and embedding in epoxy or acrylic resins. Thin sections 70 nm thick were cut on a diamond knife and imaged without grid stains at 60 kV using a CCD camera on a transmission electron microscope (TEM). Integrated intensities in digital electron micrographs were related directly to protein density, which is linearly related to RI for a given substance. The RI of the MLB interior was calculated assuming an RI value of 1.42 for the cytoplasm from the literature. Calculated RI values for MLBs ranged from 1.35 to 1.53. Thus...
Electronic imaging clinical implementation strategies and principles need to be developed as we move toward replacement of film-based radiology practices. During an 8-month period (1998 to 1999), an Electronic Imaging Clinical Implementation Work Group (EICIWG) was formed from sections of our department: Informatics Lab, Finance Committee, Management Section, Regional Practice Group, as well as several organ and image modality sections of the Department of Diagnostic Radiology. This group was formed to study and implement policies and strategies regarding implementation of electronic imaging into our practice. The following clinical practice issues were identified as key focus areas: (1) optimal electronic worklist organization; (2) how and when to link images with reports; (3) how to redistribute technical and professional relative value units (RVU); (4) how to facilitate future practice changes within our department regarding physical location and work redistribution; and (5) how to integrate off-campus imaging into on-campus work-flow. The EICIWG divided their efforts into two phases. Phase I consisted of Fact finding and review of current practice patterns and current economic models, as well as radiology consulting needs. Phase II involved the development of recommendations...
Early picture archiving and communication systems (PACS) were characterized by the use of very expensive hardware devices, cumbersome display stations, duplication of database content, lack of interfaces to other clinical information systems, and immaturity in their understanding of the folder manager concepts and workflow reengineering. They were implemented historically at large academic medical centers by biomedical engineers and imaging informaticists. PACS were nonstandard, home-grown projects with mixed clinical acceptance. However, they clearly showed the great potential for PACS and filmless medical imaging. Filmless radiology is a reality today. The advent of efficient softcopy display of images provides a means for dealing with the ever-increasing number of studies and number of images per study. Computer power has increased, and archival storage cost has decreased to the extent that the economics of PACS is justifiable with respect to film. Network bandwidths have increased to allow large studies of many megabytes to arrive at display stations within seconds of examination completion. PACS vendors have recognized the need for efficient workflow and have built systems with intelligence in the mangement of patient data. Close integration with the hospital information system (HIS)-radiology information system (RIS) is critical for system functionality. Successful implementation of PACS requires integration or interoperation with hospital and radiology information systems. Besides the economic advantages...
Reference intervals (RIs) of serum thyroid stimulating hormone (TSH) and free thyroxine (fT4) were determined in 402 healthy pregnant women by enzyme-linked immunosorbent assay (ELISA) technique after partitioning them into three trimesters. The reference population was chosen from a study population of 610 pregnant females by applying strict inclusion and exclusion criteria. The assays were done using proper quality control measures. RIs were calculated from the central 95 % of the distribution of TSH and fT4 values located between the lower reference limit of 2.5 percentile and upper reference limit of 97.5 percentile value 0.90 confidence intervals for the upper and lower reference limits were also determined. The reference intervals for TSH were 0.25–3.35 μIU/ml for the first trimester; 0.78–4.96 μIU/ml for the second trimester and 0.89–4.6 μIU/ml for the third trimester. Similarly, the reference intervals for fT4 for first, second and third trimesters were 0.64–2.0, 0.53–2.12 and 0.64–1.98 ng/dl respectively. The values thus obtained varied from those provided by the kit literature. In comparison to our derived reference intervals, the reference data from kit manufacturer under-diagnosed both subclinical hypo- and hyper-thyroidism within our pregnant reference population.
Labor costs in Francophone Africa are
considered high by the standards of low-income countries, at
least in the formal sector. Are they a brake on
industrialization, or the result of successful enterprise
development? Are they imposed on firms by powerful unions,
or government regulations, or a by-product of good firm
performance? The authors empirically analyze what determines
manufacturing wages in Cote d'Ivoire, using an
unbalanced panel of individual wages that allows them to
control for observable firm-specific effects. They test the
rent-sharing, and hold-up theories of wage determination, as
well as some aspects of efficiency-wage theories. Their
results lean in favor of both rent-sharing, and hold-up,
suggesting that workers have some bargaining power, and that
in Cote d'Ivoire workers can force renegotiation of
labor contracts, in response to new investments.
Bennett, Martin; Ditzel, Evert; Hunter, Allen; Khan, Karl; Kopp, Mikchael; Neumann, Horst; Robertson, Glen; Zeh, Harald
Fonte: Royal Society of ChemistryPublicador: Royal Society of Chemistry
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
Routes to hydrido- and organo-iron complexes of the bidentate ligand o-phenylenebis(dimethylphosphine), o-C6H4(PMe2)2 (pdmp), have been developed, starting from trans-[FeCl2(pdmp)2]. Reduction of trans-[FeC\2(pdmp)2] with LiAlH4 gives the dihydride, cw-[FeH2(pdmp)2], there being no evidence for an intermediate monohydride [FeHCl(pdmp)2]. Treatment of /ra/w-[FeCl2(pdmp)2] with an excess of methyllithium gives [FeMe2(pdmp)2], isolated as a cis//ra;;s-mixture, the methyl groups of which are cleaved by an excess of HX to give [FeX2(pdmp)2] (X = Cl, Br), predominantly in the form of the c/s-isomers. Other new complexes include [FeCI(Me)(pdmp)2] (m//ra;u-mixture) and [Fe(L)(pdmp)2] [L = CO, T|2-C2H4, n2-C8H8, nM,4-C8H6(SiMe3)2, r]2-C4H6, r|2-PhC2Ph and r|2-MeC2Me]. Treatment of/ra/j.c-[FeCl2(pdmp)2] with sodium-naphthalene generates the hydrido(naphthyl)iron(n) complex [FeH(r(1-CIOH7)(pdmp)2] as a cis/trans-mixlute in tautomeric equilibrium with a zerovalent iron naphthalene complex [Fe(r|2-C,0H8)(pdmp)2]. Single crystal X-ray analysis shows that [Fe(n2-C2H4)(pdmp)2] has a distorted octahedral structure in which the ethylene is twisted by ca. 15° relative to the FeP4 skeleton, probably because of steric effects. In solution the coordinated ethylene rotates about the coordination axis with a free energy of activation ΔCt at 324 K of 67 kJ mol-1...