3,678 research outputs found
Application of gravel pack technology to the "X" field on Sakhalin island
One of the factors that complicates the operation of wells is the content of mechanical impurities in the reservoir fluid. The removal of mechanical impurities along with oil occurs in many oil-producing regions of Russia and some foreign countries. In such conditions, the inter-repair period of downhole equipment is sharply reduced. Hydrocarbons obtained from poorly fortified reservoirs may contain small bodies such as clays and sand. Installing sand control equipment without affecting productivity, flow control and mineral extraction is a complex and expensive task. However, repair costs are very high, especially for deep-water wells. At the "X" field, it is necessary to use reliable methods of sand control in wells, the gravel pack method provides an effective solution
Magnetic flux, Wilson line and orbifold
We study torus/orbifold models with magnetic flux and Wilson line background.
The number of zero-modes and their profiles depend on those backgrounds. That
has interesting implications from the viewpoint of particle phenomenology.Comment: 1+17 pages, 1 figur
Treatment of mild chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is an epidemic in many parts of the world. Most patients with COPD demonstrate mild disease. The cornerstone of management of mild disease is smoking cessation, which is the only proven intervention to relieve symptoms, modify its natural history and reduce mortality. For asymptomatic patients, it is the only required therapy. Short-acting bronchodilators can be added on an as needed basis for those with intermittent symptoms and regularly for those with persistent symptoms. Long-acting bronchodilators can be substituted for those who remain symptomatic despite regular use of short-acting bronchodilators. Inhaled corticosteroids do not modify the natural history of COPD and as such cannot be recommended as standalone therapy for mild COPD. However, for patients with refractory and intractable symptoms, they may be used in combination with long-acting beta-2 agonists. Influenza and pneumococcal vaccination and pulmonary rehabilitation are other therapies that may be considered for select patients with mild disease. In this paper, we summarize the current standard of care for patients with mild COPD
The Cosmic Gamma-Ray Background from Type Ia Supernovae
We present an improved calculation of the cumulative gamma-ray spectrum of Type Ia supernovae during the history of the universe. We follow Clayton & Ward (1975) in using a few Friedmann models and two simple histories of the average galaxian nucleosynthesis rate, but we improve their calculation by modeling the gamma-ray scattering in detailed numerical models of SN Ia\u27s. The results confirm that near 1 MeV the SN Ia background may dominate, and that it is potentially observable, with high scientific importance. A very accurate measurement of the cosmic background spectrum between 0.1 and 1.0 MeV may reveal the turn-on time and the evolution of the rate of Type Ia supernova nucleosynthesis in the universe
Degradation Parameters from Pulse-Chase Experiments
Pulse-chase experiments are often used to study the degradation of macromolecules such as proteins or mRNA. Considerations for the choice of pulse length include the toxicity of the pulse to the cell and maximization of labeling. In the general case of non-exponential decay, varying the length of the pulse results in decay patterns that look different. Analysis of these patterns without consideration to pulse length would yield incorrect degradation parameters. Here we propose a method that constructively includes pulse length in the analysis of decay patterns and extracts the parameters of the underlying degradation process. We also show how to extract decay parameters reliably from measurements taken during the pulse phase
Integrative Approach to Quality Assessment of Medical Journals Using Impact Factor, Eigenfactor, and Article Influence Scores
BACKGROUND: Impact factor (IF) is a commonly used surrogate for assessing the scientific quality of journals and articles. There is growing discontent in the medical community with the use of this quality assessment tool because of its many inherent limitations. To help address such concerns, Eigenfactor (ES) and Article Influence scores (AIS) have been devised to assess scientific impact of journals. The principal aim was to compare the temporal trends in IF, ES, and AIS on the rank order of leading medical journals over time. METHODS: The 2001 to 2008 IF, ES, AIS, and number of citable items (CI) of 35 leading medical journals were collected from the Institute of Scientific Information (ISI) and the http://www.eigenfactor.org databases. The journals were ranked based on the published 2008 ES, AIS, and IF scores. Temporal score trends and variations were analyzed. RESULTS: In general, the AIS and IF values provided similar rank orders. Using ES values resulted in large changes in the rank orders with higher ranking being assigned to journals that publish a large volume of articles. Since 2001, the IF and AIS of most journals increased significantly; however the ES increased in only 51% of the journals in the analysis. Conversely, 26% of journals experienced a downward trend in their ES, while the rest experienced no significant changes (23%). This discordance between temporal trends in IF and ES was largely driven by temporal changes in the number of CI published by the journals. CONCLUSION: The rank order of medical journals changes depending on whether IF, AIS or ES is used. All of these metrics are sensitive to the number of citable items published by journals. Consumers should thus consider all of these metrics rather than just IF alone in assessing the influence and importance of medical journals in their respective disciplines
Discrete R-symmetry anomalies in heterotic orbifold models
Anomalies of discrete R-symmetries appearing in heterotic orbifold models are
studied. We find that the mixed anomalies for different gauge groups satisfy
the universal Green-Schwarz (GS) condition, indicating that these anomalies are
canceled by the GS mechanism. An exact relation between the anomaly
coefficients of the discrete R-symmetries and one-loop beta-function
coefficients is obtained. We also find that the discrete R-symmetries have a
good chance to be unbroken down to the supersymmetry breaking scale. Even below
this scale a subgroup is unbroken, which may be an origin of the R-parity
of the minimal supersymmetric standard model. Relations between the R-symmetry
anomalies and T-duality anomalies are also investigated.Comment: 19 pages, no figur
Water Quality, Aquatic Life and Fish in Song Bung River. A Part Study of the Environmental Impact Assesment for the Song Bung 4 Hydropower Development Project in Central Vietnam
Årsliste 2007The study comprise three main tasks: 1) Assess the present situation in the river with respect to water quality, aquatic life, fish and fishery; 2) Assess the impact of the hydropower regulation scheme on these items, and 3) Propose and outline mitigation measures to reduce the negative impacts. The study also deals with impact from mining and how this will conflict with the regulation plans. It also elucidates the potential for releases of greenhouse gases from the reservoir. Finally the study proposes a monitoring programme, as well as Terms of Reference for a study of the aquatic resources in the whole Vu Gia River system.Asian Development Ban
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