bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation Mechanism of the Tongyu Gold Deposit, Shaanxi —— A Discussion of a Model for the Formation of Syntectonic Gold Deposits
Authors: Zhengguo Hu , Zhuangzhi Qian 
Published: August 2010

Abstract The formation of the Tongyu gold deposit, controlled by regional polyphase deformation‐metamorphism, is closely related to the regional composite antiform‐shear slip fracture zone. Late‐stage reworking of the Taihua Group accounts for the enrichment of ore substances. It is a typical syntectonic gold deposit.The formation and evolution of the deposit involved four stages: ( I ) the stage of preparation of ore substances, in which primary source beds originated; (II ) the stage of remobilization of ore substances, in which regional progressive metamorphism and migmatization and thermodynamic‐chemical differentiation led to remobilization of gold and its initial local concentration; (III) the stage of gold deposit formation, in which regional folding produced concordant and cross shear‐slip fractures and under the dynamic action gold was separated and migrated in a certain direction and concentrated to form a gold deposit; (IV ) the stage of superpositon, reworking and exposure of orebodies, in which the block uplifted and the deposit again underwent reworking through faulting and mechanical differentiation. Thermodynamic mineralization played a dominant role in the formation of the deposit.
Metabasic Dyke Swarms in a High‐Grade Metamorphic Terrane—A Case Study in the Taipingzhai‐Jinchangyu Area, Eastern Hebei Province
Authors: Manyun Chen 
Published: August 2010

Abstract Geological and penological studies indicate that three phases of metabasic dykes are present in the Taipingzhai‐ Jinchangyu area within the high‐ grade metamorphic terrane of eastern Hebei. Garnet and hornblende in metabasic dykes of the second and third phases occur separately, forming two mineral aggregate areas gt+cpx+pl± hy and hb+cpx+pl± hy. PH2O in the rocks appears to be the main factor controlling the formation of the two aggregate areas. Both were formed simultaneously at the same metamorphic temperature.The second‐phase basic dykes underwent metamorphism of pyroxene‐granulite facies at a temperature pf some 825°C ; later the dykes, together with the third‐ phase basic dykes experienced metamorphism of amphibole‐granulite facies at a temperature of about 750°C under pressure of 0.9GPa.
Preliminary Study of the Characteristics and Genesis of Arsenate Minerals in the Oxidized Zone of the Debao Skarn‐Type Cu‐Sn Ore Deposit in Guangxi
Authors: Yi Li , Lairen Lai 
Published: August 2010

Abstract Through the study of the oxidized zone of the Debao skarn‐type Cu‐Sn deposit in Guangxi, the authors have found 14 arsenate minerais, most of which are for the first time reported in China. They are mainly Cu arsenate minerais with subordinate Cu‐Pb arsenate minerais and minor Fe‐Pb‐Ba varieties.Based on their paragenesis these minerais may be divided into the following series: (1) the clinoclasite‐olivenite‐cornwallite‐cornubite‐debaoite‐copper silicarsenate association, (2) the scorodite‐carminite‐beudan‐tite‐bayldonite‐ duftite association, and (3) the scorodite‐Ba‐bearing pharmacosiderite‐ dussertite association.Arsenate minerais are formed generally in the oxidized zone of the sulfide‐type deposits which lie in the warm, humid and rainy torrid‐subtropical zone with pH = 6‐8 and contain large amounts of arsenopyrite and carbonate rocks.
The Sedimentation and Formation Mechanism of Lacustrine Endogenic Debris Flow
Authors: Deping Wang 
Published: August 2010

Abstract The debris flow formed by mass transportation of lacustrine deltaic sediments is quite unique compared with subaerial one, and is called “endogenic debris flow” in this paper. The major diagnostic features of endogenic debris flow sediments are muddy rip‐ups, sandy lumps, randomly distributed carbonaceous plant leaves and rhyotaxitic structure. However, such debris flow can not be completely generalized by the conclusion that larger granules are supported by cohesive strength of the matrix. The fact that sediments can be transported in plastic state is considered to be related with two different functions of combined clay‐water materials: serving as a matrix in texture and as an adhesive between grains. This paper also discusses the origin and sediment types of endogenic debris flow as well as the general concepts of matrix and debris flow.From the viewpoint of “true debris flow”, this paper attempts to generalize and illustrate the basic features and variation of endogenic debris flow sediments on the basis of the Bingham (Coulomb‐viscosity) model.
Rare Earth Elements in Manganese Nodules from the Central Pacific Ocean
Authors: Shiqin Guo , Wenhong Sun 
Published: August 2010

Abstract Manganese nodules in areas CP and CC of the central Pacific are rich in REE. Comparatively speaking, the REE contents of nodules in area CP are hihger than those in area CC; and the REE contents of nodules from seamounts are higher than those of nodules from sea‐floor plains and hills. Within the nodules, the REE show a zonal distribution. The REE distribution patterns of the nodules are similar to those of the sediments and have a mirror image relationship with those of the sea water. Trivalent REE were not obviously differentiated when they entered into the nodules from the sea water.A major factor causing the difference of REE abundances between nodules and sediments is the redox conditions. The redox intensity of the ocean floor of the Pacific is controlled mainly by Antarctic Bottom Water (AABW). The iron‐bearing facies in the nodules is the main carrier of REE.
A Comparative Study of Numercial Solution of PDE in Geosciences
Authors: Hongren Zhang 
Published: August 2010

Abstract A number of phenomena and processes in geosciences can be summarized by second order partial differential equations. The major numerical methods for their solution include the classical finite difference method and the finite element method newly developed in the last two or three decades. Since 1977 the author has proved that for the Laplace and Poisson equations, these two methods are identical and are different only in the process of formulation. For transient problems, such as heat conduction in the earth and the groundwater and oil‐gas unsteady flow in porous media, there are some differences in resulting linear algebraic euqations. In general, two methods give similar results, but when the time step is decreased to some extent, the resulting. algebraic equation will be consistent with the anti‐heat conduction equation rather than the original heat conduction equation. This is the reason why unrealistic potentials are produced by the finite element method. Such a problem can be overcome by using the lumped mass procedure, but it makes the two methods identical again.To improve the traditional finite difference method, it is quite desirable to introduce the common practice of the finite element method to define the parameters in elements rather than on nodes.
Factors Associated With the Risk of West Nile Virus Among Crows in New York State
Authors: DeCarlo C. H. , Clark A. B. , McGowan K. J. , Ziegler P. E. , Glaser A. L. , Szonyi B. , Mohammed H. O. 
Published: August 2010

SummaryWest Nile virus (WNV) is transmitted between avian hosts in enzootic cycles by a mosquito vector. The virus has significant disease effects on humans and equines when it bridges into an epizootic cycle. As the initial epidemic of WNV in 1999, perennial outbreaks in New York State suggest the local establishment of natural foci with perpetuation of the virus among susceptible hosts rather than reintroduction of the virus. The factors that play a role in the perpetuation of the virus are not fully understood. American crows (Corvus brachyrhynchos) are known to be highly susceptible to infection with the virus. We investigate the factors that put crows at risk of infection in Tompkins County, New York during the period of 2000–2008 in a case–control study. Cases were crow carcasses that were found dead and tested positive for WNV using real time reverse transcription or VecTest®. Data on putative risk factors were collected and assessed for significance of association with the presence of WNV using logistic regression analysis to evaluate the significance of each factor while simultaneously controlling for the effect of others. The risk of a crow carcass testing WNV positive varied with age, season of the year and ecological area where the carcass was found. Crows that were more than 1‐year‐old were four times more likely to be WNV positive in comparison to birds that were less than 1 year of age. It was three times more likely to find WNV positive carcasses in residential areas in comparison to rural areas. The risk of testing WNV positive did not vary by sex of the crow carcasses.
MODELS FOR OPTIMAL LEAD TIME REDUCTION
Authors: HILL ARTHUR V. , KHOSLA INDER S. 
Published: August 2010

Most inventory and production planning models in the academic literature treat lead times either as constants or random variables with known distributions outside of management control. However, a number of recent articles in the popular press have argued that reducing lead times is a dominant issue in manufacturing strategy. The benefits of reducing customer lead times that are frequently cited include increased customer demand, improved quality, reduced unit cost, lower carrying cost, shorter forecast horizon, less safety stock inventory, and better market position. Although the costs of reducing lead times in the long term may be relatively insignificant compared with the benefits, in the short term these costs can have a significant impact on the profitability of a firm. This article develops a conceptual framework within which the costs and benefits of lead time reduction can be compared. Mathematical models for optimal lead time reduction are developed within this framework. The solutions to these models provide methods for calculating optimal lead times, which can be applied in practice. Sensitivity analysis of the optimal solutions provides insight into the structure of these solutions.
COMMON DUE‐WINDOW SCHEDULING
Authors: KRÄMER FRANZ‐JOSEF , LEE CHUNG‐YEE 
Published: August 2010

In this paper, we solve common due‐window scheduling problems within the just‐in‐time window concept, i.e., scheduling problems including both earliness and tardiness penalties. We assume that jobs share the same due window and incur no penalty as long as they are completed within the due window. We further assume that the earliness and tardiness penalty factors are constant and that the size of the window is a given parameter. For cases where the location of the due window is a decision variable, we provide a polynomial algorithm with complexity O( n * log ( n)) to solve the problem. For cases where the location of the due window is a given parameter, we use dynamic programming with pseudopolynomial complexity to solve the problem.
A COMPARISON OF RULES FOR ALLOCATING SETUP‐REDUCTION INVESTMENTS IN A CAPACITATED ENVIRONMENT
Authors: LESCHKE JOHN P. , WEISS ELLIOTT N. 
Published: August 2010

This paper builds on a recent empirical study of the setup‐reduction process that suggests setup‐reduction proceeds through three major stages and that each stage is dominated by a particular type of investment function. Specifically, it examines the question of how to best prioritize investments during the stage that emphasizes standardizing setups across a work center. We compare different investment‐allocation rules in a multi‐item, capacity‐constrained, dynamic demand environment under a variety of cost, demand, and investment assumptions. This analysis shows that significant differences in benefits can be achieved depending on the way setup‐reduction investments are prioritized.
THE PERILS OF EXCELLENCE: BARRIERS TO EFFECTIVE PROCESS IMPROVEMENT IN PRODUCT‐DRIVEN FIRMS
Authors: HENDERSON REBECCA , DELALAMO JESUS , BECKER TODD , LAWTON JAMES , MORAN PETER , SHAPIRO SAUL 
Published: August 2010

Several authors have suggested that a focus on manufacturing capability and on continued process improvement may be a powerful source of competitive advantage, yet many firms appear to have encountered great difficulties in taking advantage of this insight. This paper reports on the results of five these conducted under the auspices of the MIT Leaders for Manufacturing program at the Microwave Technology Division of the Hewlett‐Packard Company. We found considerable evidence that the marginal returns to process development within the division were probably considerably higher than the division's cost of capital, suggesting that process improvement probably was underfunded despite the fact that improving manufacturing capability had been identified as a key strategic priority. We found no evidence that this “underfunding” reflected either a failure to recognize the problem or an overly hierarchical or rigid organization. Rather it appeared to flow from the historical strengths of the division. A devotion to leading‐edge technical solutions and to immediate customer service at almost any price had created barriers to the effective funding of process improvement that were deeply rooted in the organizational structures, information systems, and formal and informal incentive structures that had evolved to support the division's historical emphasis on excellence on product design. Our results highlight the problems that very successful product‐driven companies may encounter in attempting to make continual process improvement central to their strategic mission.
COMPUTER INTEGRATION AND CATASTROPHIC PROCESS FAILURE IN FLEXIBLE PRODUCTION: AN EMPIRICAL INVESTIGATION
Authors: UPTON DAVID M. , MCAFEE ANDREW P. 
Published: August 2010

This paper empirically investigates the effect of advanced manufacturing technology on process stability during flexible production in a process industry. A sample of 61 North American fine paper plants is used to examine the relationship between the level of automation installed for controlling changes between paper grades and the incidence of paper web breaks. These web breaks are catastrophic failures; they require the entire plant to be stopped, reinitialized, and restarted. Because a large fraction of breaks occurs shortly after changeovers, they are an important determinant of the aspect of plant flexibility, called mobility, or the ability to move between products with only small penalties. In an attempt to ensure stable and mobile production, many plants have implemented changeover automation. We find, however, that higher levels of this automation are significantly associated with higher rates of catastrophic failure among the plants studied. We suggest that this finding becomes less paradoxical when considered in light of a recent stream of research on advanced manufacturing technologies, loosely called the usability perspective. According to this perspective, automation designed and implemented with the narrow, technical goal of replacing human operators or removing their discretion over a production process is misguided, especially in environments in which requirements are changing rapidly.
MULTIPLE RATERS IN SURVEY‐BASED OPERATIONS MANAGEMENT RESEARCH: A REVIEW AND TUTORIAL
Authors: Boyer Kenneth K. , Verma Rohit 
Published: August 2010

Research in the area of operations strategy has made significant progress during the past decade in terms of quantity of articles published, as well as the quality of these articles. Recent studies have examined the published literature base and determined that, in general, the field has progressed beyond an exploratory stage to a point where there is a core set of basic terminology and models. Concurrent with the formation and solidification of a core terminology, there is an increasing emphasis on developing and employing a set of reliable, valid, and reproducible methods for conducting research on operations strategy. We provide a review of common methods for assessing the degree of reliability and agreement of the responses provided by multiple raters within a given organization to a set of qualitative questions. In particular, we examine four methods of determining whether there is evidence of disagreement or bias between multiple raters within a single organization in a mail survey.
Empirical Research Published in Production and Operations Management (1992–2005): Trends and Future Research Directions
Authors: Gupta Sushil , Verma Rohit , Victorino Liana 
Published: August 2010

We review and evaluate empirical research in more than 150 papers published in Production and Operations Management ( POM) during 1992 to 2005 to assess how far the papers' authors have met the journaľs stated objective of promoting empirical research. We also assess the diversity of articles in terms of the purposes of research, data collection approaches, and data analysis techniques. We classify the empirical research articles based on their primary purpose (theory building, theory verifying, application, and providing evidence), data collection approach (case study, qualitative research, archival research, survey‐based research, laboratory research, and field research), data analysis technique (descriptive statistics, various multivariate statistical techniques, and mathematical modeling), and operations topics (strategy, quality, and supply chain management). We also discuss directions for future empirical research in operations management. During 1992 to 2005, the articles based on empirical data have increased substantially from 30 to 50 percent of all articles published in POM. During 1992 to 1998, about three‐fourths of the empirical‐research‐based articles published in POM focused on the manufacturing industry, but recently the gap between the numbers of manufacturing‐ and service‐focused articles published in POM has almost disappeared. While a previous assessment of articles published in a range of operations management journals showed that almost all of the empirical articles were based on either surveys or case studies, our results indicate that POM has published articles that were based on a much wider and more diverse range of data collection approaches. Production and Operations Management has clearly established itself as a leading outlet for publishing empirical research in operations management.
EXISTENCE AND UNIQUENESS FOR HEIGHT STRUCTURED HIERARCHICAL POPULATION MODELS
Authors: KRAEV EGOR A. 
Published: August 2010

ABSTRACT. We consider a nonlinear height‐structured McKendrick forest model with vital rates of a tree depending on its height and the total leaf area above it, represented as a weighted integral over all higher trees. We consider two types of the weighing factor, corresponding to foliage being concentrated on top of a tree, respectively distributed continuously along the trunk.We prove local existence of continuous solutions for continuous initial conditions and derive a sharp condition on the coefficients ensuring the existence of global in time, continuous solutions for arbitrary continuous data.In the case where this condition is not fulfilled, we illustrate how singularities can emerge out of continuous initial conditions by relating our model to Burgers' equation.The analysis uses a coordinate transform which brings the model into a particularly simple form, reducing the first order partial differential equation to a family of coupled ordinary differential equations for population density and height as functions of characteristic variables.
Organizational Challenges and Strategic Responses of Retail TNCs in Post‐WTO‐Entry China
Authors: Tacconelli Wance , Wrigley Neil 
Published: August 2010

abstractIn the context of a market characterized by the enduring legacy of socialism through governmental ownership of retail businesses, the continued presence of domestic retailers, and increasing levels of competition, this article examines the organizational challenges faced by, and the strategic responses adopted by, a group of leading food and general merchandise retail transnational corporations (TNCs) in developing networks of stores in the post‐WTO‐entry Chinese market. On the basis of extensive interview‐based fieldwork conducted in China from 2006 to 2008, the article details the attempts of these retail TNCs to embed their operations in Chinese logistics and supply networks, real estate markets, and consumer cultures—three dimensions that are fundamental to the achievement of market competitiveness by the retail TNCs. The article illustrates how this process of territorial embeddedness presents major challenges for the retail TNCs and how their strategic responses vary substantially, indicating different routes to the achievement of organizational legitimacy in China. The article concludes by offering an analysis of the various strategic responses of the retail TNCs and by suggesting some future research propositions on the globalization of the retail industry.
Evolutionary Economic Geography, Institutions, and Political Economy
Authors: Essletzbichler Jürgen 
Published: August 2010

abstractIn this response to MacKinnon et al. (2009), I argue that the theoretical development of evolutionary economic geographies is necessary in order to evaluate its unique contribution to an understanding of the uneven development of the space economy; that the distinction between evolutionary and institutional economic geographies is overdrawn; that the neglect of class, power, and the state reflect empirical rather than theoretical shortcomings of the evolutionary approach; and that there is significant potential overlap between evolutionary and political economy approaches.
Bimodules and branes in deformation quantization
Authors: Calaque Damien , Felder Giovanni , Ferrario Andrea , Rossi Carlo A. 
Published: August 2010

AbstractWe prove a version of Kontsevich’s formality theorem for two subspaces (branes) of a vector space X. The result implies, in particular, that the Kontsevich deformation quantizations of S(X*) and ∧(X) associated with a quadratic Poisson structure are Koszul dual. This answers an open question in Shoikhet’s recent paper on Koszul duality in deformation quantization.
Does a gating policy for ANCA overlook patients with ANCA associated vasculitis? An audit of 263 patients
Authors: Arnold D F , Timms A , Luqmani R , Misbah S A 
Published: August 2010

BackgroundAntineutrophil cytoplasm antibodies (ANCA) are used as diagnostic markers for small-vessel vasculitis of the Wegener Granulomatosis-microscopic polyangiitis (WG-MPA) spectrum, but if testing is applied indiscriminately, its value is diminished. The authors measured the effect of a targeted ANCA testing policy introduced in our institution in an attempt to improve the diagnostic value of testing in patients with suspected vasculitis.MethodsThe authors measured the rate of ANCA requests at a single regional centre in the year prior to and following the introduction of clinical guidelines to ensure appropriate test usage. The authors also audited clinical outcomes in patients in whom ANCA testing was declined.ResultFollowing implementation of the antineutrophil cytoplasm antibodies (ANCA) gating policy, the number of monthly ANCA tests carried out fell from 287±30 to 143±18 (p<0.0001) and was associated with an increased rate of positivity, from 18.5% (95% CI 17.0 to 20.1%) to 30.3% (27.5 to 33.1%; p<0.0001). The authors undertook a careful review of the case records from 263 patients in whom testing was declined according to the gating policy over an 8-month period. After 6 months' follow-up, no diagnoses of small-vessel vasculitis of the WG-MPA spectrum were reached.ConclusionsThe rational use of ANCA testing to aid in the diagnosis of vasculitis should include a clinical gating policy to improve diagnostic performance. Adherence to a gating policy for ANCA testing coupled with close liaison between clinician and laboratory does not result in either a missed or delayed diagnosis of small-vessel vasculitis belonging to the WG-MPA spectrum.