bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploiting gene‐environment independence in family‐based case‐control studies: Increased power for detecting associations, interactions and joint effects
Authors: Chatterjee Nilanjan , Kalaylioglu Zeynep , Carroll Raymond J. 
Published: December 2004

AbstractFamily‐based case‐control studies are popularly used to study the effect of genes and gene‐environment interactions in the etiology of rare complex diseases. We consider methods for the analysis of such studies under the assumption that genetic susceptibility (G) and environmental exposures (E) are independently distributed of each other within families in the source population. Conditional logistic regression, the traditional method of analysis of the data, fails to exploit the independence assumption and hence can be inefficient. Alternatively, one can estimate the multiplicative interaction between G and E more efficiently using cases only, but the required population‐based G‐E independence assumption is very stringent. In this article, we propose a novel conditional likelihood framework for exploiting the within‐family G‐E independence assumption. This approach leads to a simple and yet highly efficient method of estimating interaction and various other risk parameters of scientific interest. Moreover, we show that the same paradigm also leads to a number of alternative and even more efficient methods for analysis of family‐based case‐control studies when parental genotype information is available on the case‐control study participants. Based on these methods, we evaluate different family‐based study designs by examining their relative efficiencies to each other and their efficiencies compared to a population‐based case‐control design of unrelated subjects. These comparisons reveal important design implications. Extensions of the methodologies for dealing with complex family studies are also discussed. Genet Epidemiol. 28:138–156, 2005. © 2004 Wiley‐Liss, Inc.
Determinants of participation and nonparticipation in job‐related education and training in Shenzhen, China
Authors: Xiao Jin , Tsang Mun C. 
Published: December 2004

AbstractIn the fast‐growing market‐oriented economy of Shenzhen, China, most employees have continued to participate in job‐related education and training. We argue that as firms have acquired autonomy in their operations and individuals have gained the right to pursue their personal occupational aspirations, non–state‐sponsored education and training systems for the working population have developed to respond to the demands from firms, as well as individuals. With survey data from 3,475 employees in seventy‐six firms from Shenzhen, this study uses a multinomial model to examine patterns in employee participation in job‐related education and training. There are basically four options open to employees: taking part in education and training provided by a firm to its own employees, enrolling in education and training offered by institutions outside the firm, availing themselves of both options simultaneously, or not participating. Our findings suggest that these four groups of employees vary in terms of their cultural and symbolic attributes, their individual socioeconomic attributes in relation to their workplace, and the economic attributes of their firm.
Evaluating wetland flow regulating functions using discharge time‐series
Authors: Smakhtin V. U. , Batchelor A. L. 
Published: December 2004

AbstractThis paper describes a parsimonious approach for the evaluation of wetland hydrological functions, based on continuous observed streamflow records and flow duration curves. The functions evaluated are baseflow maintenance and flood attenuation, jointly referred to as ‘flow regulation’. The first step in this evaluation is to establish a reference hydrological condition. This condition is defined in terms of mean daily and instantaneous daily maximum flow time‐series and their corresponding duration curves, assuming that there is no wetland in the catchment. Further steps include calculating the changes of various flow percentiles, caused by the presence of a wetland, detailed hydrograph analysis, baseflow analysis and analysis of changes in characteristics of continuous flow events above and below specified threshold discharges. The method is illustrated using the observed streamflow data in the catchment of the Rustenburg wetland in South Africa. Copyright © 2004 John Wiley & Sons, Ltd.
Modelling stream flow for use in ecological studies in a large, arid zone river, central Australia
Authors: Costelloe Justin F. , Grayson Rodger B. , McMahon Thomas A. 
Published: December 2004

AbstractAustralian arid zone ephemeral rivers are typically unregulated and maintain a high level of biodiversity and ecological health. Understanding the ecosystem functions of these rivers requires an understanding of their hydrology. These rivers are typified by highly variable hydrological regimes and a paucity, often a complete absence, of hydrological data to describe these flow regimes. A daily time‐step, grid‐based, conceptual rainfall–runoff model was developed for the previously uninstrumented Neales River in the arid zone of northern South Australia. Hourly, logged stage data provided a record of stream‐flow events in the river system. In conjunction with opportunistic gaugings of stream‐flow events, these data were used in the calibration of the model. The poorly constrained spatial variability of rainfall distribution and catchment characteristics (e.g. storage depths) limited the accuracy of the model in replicating the absolute magnitudes and volumes of stream‐flow events. In particular, small but ecologically important flow events were poorly modelled. Model performance was improved by the application of catchment‐wide processes replicating quick runoff from high intensity rainfall and improving the area inundated versus discharge relationship in the channel sections of the model. Representing areas of high and low soil moisture storage depths in the hillslope areas of the catchment also improved the model performance. The need for some explicit representation of the spatial variability of catchment characteristics (e.g. channel/floodplain, low storage hillslope and high storage hillslope) to effectively model the range of stream‐flow events makes the development of relatively complex rainfall–runoff models necessary for multisite ecological studies in large, ungauged arid zone catchments. Grid‐based conceptual models provide a good balance between providing the capacity to easily define land types with differing rainfall–runoff responses, flexibility in defining data output points and a parsimonious water‐balance–routing model. Copyright © 2004 John Wiley & Sons, Ltd.
Effects of commercial timber harvesting on streamflow regimes in the Plynlimon catchments, mid‐Wales
Authors: Robinson M. , Dupeyrat A. 
Published: December 2004

AbstractThis paper presents the first large‐scale British study of the impacts of commercial forest cutting on stream‐flow regimes. The 70% forested headwaters of the River Severn are part of the intensively instrumented long‐term Plynlimon catchment study into the impact of land use on stream flow. The forest area, comprising predominantly Sitka spruce (Picea sitchensis), was planted mainly in the 1930s and 1940s. Harvesting commenced in the mid‐1980s and over the study period about half the forest has been felled. Changes in annual water yield and extreme flows were studied in four nested catchments ranging in area from about 1 to 10 km2 and compared with an adjacent benchmark grassland catchment. As expected from earlier process studies the cutting of the forest increased total annual flows. Less expected was the clear evidence that the felling augmented low flows. This informs a long‐standing debate whether upland forestry increases or reduces baseflows. A particularly notable result was the lack of impact of the harvesting on storm peak flows. This may result from the application of forest management guidelines designed to reduce soil damage and erosion during the harvesting, and indicates that the forest itself has a limited impact on flooding. These findings are timely because British forest expansion peaked in the 30 years following the Second World War, and large areas of these woodlands are now approaching economic maturity and will be harvested in the next two decades. Copyright © 2004 John Wiley & Sons, Ltd.
Modelling flow resistance in vegetated streams: review and development of new theory
Authors: Green Julian C. 
Published: December 2004

AbstractAquatic macrophytes are often the dominant factor influencing flow conditions within the channels they occupy. Existing knowledge of how stream plants affect the flow is outlined, and the different scales at which vegetation resistance operates are proposed. Resistance is shown to be a function of the size of the plants, their structural properties, location in the channel, and the local flow conditions. Current models to calculate this composite resistance effect are assessed in the light of theoretical considerations of the nature of vegetation resistance. New theory is also presented, which demonstrates the non‐linear relationship between channel resistance and the proportion of the channel occupied by vegetation. Copyright © 2004 John Wiley & Sons, Ltd.
Multivariate statistical analysis to identify the major factors governing groundwater quality in the coastal area of Kimje, South Korea
Authors: Kim Ji‐Hoon , Kim Rak‐Hyeon , Lee Jeongho , Cheong Tae‐Jin , Yum Byoung‐Woo , Chang Ho‐Wan 
Published: December 2004

AbstractThe main purpose of this study is to identify the major factors affecting groundwater quality by means of multivariate statistical analysis of the physico‐chemical compositions. Cluster analysis results show that the groundwater in the study area is classified into four groups (A, B, C and D), and factor analysis indicates that groundwater composition, 81·9% of the total variance of 17 variables, is mainly affected by three factors: seawater intrusion, microbial activity and chemical fertilizers. These results might be related to the geographical characteristics of the study area. The main influence on groundwater in groups B, C and D, which are close to the Yellow Sea and contain reclaimed areas, is the seawater intrusion by the present seawater, the trapped seawater, and microbial activity. Group A, however, has been used for agriculture for a long time, and thus groundwater in this group has been largely affected by chemical fertilizers. As groundwater flows from group A to group D according to its path, the governing factor of the groundwater quality gradually changes from chemical fertilizers to microbial activity and seawater intrusion. Copyright © 2004 John Wiley & Sons, Ltd.
How to construct recursive digital filters for baseflow separation
Authors: Eckhardt K. 
Published: December 2004

AbstractRecursive digital filtering of hydrographs is a baseflow separation method that can easily be automated and has been recommended for providing reproducible results. In the past, different formulations of the most simple filter type, the so‐called one‐parameter filter, have been proposed. In this paper, a theoretical framework is developed for filter algorithms that were constructed under the assumption that the outflow from an aquifer is linearly proportional to its storage. It is shown that these one‐parameter filters describing an exponential baseflow recession are all special cases of a two‐parameter filter whose equation is specified. Its parameters are the recession constant—which can be objectively determined by a recession analysis—and BFImax, the maximum value of the baseflow index that can be modelled by the algorithm. This introduces a subjective element into the baseflow calculation, since BFImax is not measurable. A preliminary analysis based on the results of conventional separation techniques shows that it might be possible to find typical BFImax values for classes of catchments that can be unequivocally distinguished by their hydrological and hydrogeological characteristics. Copyright © 2004 John Wiley & Sons, Ltd.
Parametric pricing of higher order moments in S&P500 options
Authors: Lim G. C. , Martin G. M. , Martin V. L. 
Published: December 2004

AbstractA general parametric framework based on the generalized Student t‐distribution is developed for pricing S&P500 options. Higher order moments in stock returns as well as time‐varying volatility are priced. An important computational advantage of the proposed framework over Monte Carlo‐based pricing methods is that options can be priced using one‐dimensional quadrature integration. The empirical application is based on S&P500 options traded on select days in April 1995, a total sample of over 100,000 observations. A range of performance criteria are used to evaluate the proposed model, as well as a number of alternative models. The empirical results show that pricing higher order moments and time‐varying volatility yields improvements in the pricing of options, as well as correcting the volatility skew associated with the Black–Scholes model. Copyright © 2004 John Wiley & Sons, Ltd.
Extraction and pertraction of phenol through bulk liquid membranes
Authors: Cichy Wojciech , Schlosser Štefan , Szymanowski Jan 
Published: December 2004

AbstractThe extraction and pertraction of phenol through a bulk liquid membrane (BLM) with Cyanex® 923, Amberlite® LA‐2 and trioctylamine (TOA) as carriers were studied. Cyanex® 923 was selected as the best carrier for pertraction. The distribution coefficient of phenol for solvents with carrier and pure n‐alkanes, the individual mass‐transfer coefficient at the extraction interface and the initial flux of phenol through the extraction interface (JFo) decreased in the order: Cyanex® 923 > Amberlite® LA‐2 > TOA ≫ pure n‐alkanes. The opposite order was observed for the value of the mass‐transfer coefficient in BLM and the maximum flux of phenol through the stripping interface (JRmax). At constant driving forces the maximum fluxes through the extraction and stripping interfaces were similar when amine carriers were used. However, JRmax was lower than JFo for Cyanex® 923. Although the kinetics of stripping was the rate‐determining step, the flux of phenol was significantly higher than in pertraction with amine carriers. The adsorption of the carrier at aqueous phase/membrane interfaces was probably responsible for the rapid and slow transfer of phenol through the extraction and stripping interface, respectively. Copyright © 2004 Society of Chemical Industry
Simultaneous purification and immobilization of bitter gourd (Momordica charantia) peroxidases on bioaffinity support
Authors: Akhtar Suhail , Ali Khan Amjad , Husain Qayyum 
Published: December 2004

AbstractThis paper demonstrates the construction of an inexpensive bioaffinity adsorbent by simply incubating Sephadex G 50 matrix with jack bean meal extract at room temperature. Sephadex G 50 adsorbed 17 mg Con A (concanavalin A) per g of the matrix. Con A‐adsorbed Sephadex was employed for the immobilization of glycoenzymes directly from ammonium sulfate‐fractionated proteins of bitter gourd. The obtained bioaffinity support was very efficient for high yield immobilization of peroxidases from bitter gourd and it bound nearly 425 enzyme units per g of the matrix. Bitter gourd peroxidase immobilized on lectin–Sephadex support showed a very high effectiveness factor, ‘η,’ of 1.25. Immobilized BGP preparation was quite stable against the denaturation induced by pH, heat, urea, Triton X 100, Tween 20, SDS, Surf Excel and water‐miscible organic solvents: dimethyl sulfoxide and dimethyl formamide. Low concentration of detergents like SDS, Tween 20, and Triton X 100 enhanced the activity of soluble and immobilized bitter gourd peroxidase. Peroxidase bound to the bioaffinity support exhibited very high resistance to proteolysis caused by the trypsin treatment. Con A–Sephadex‐bound bitter gourd peroxidase retained 85% of its initial activity after treatment with 2.5 mg trypsin per cm3 of incubation mixture for 1 h at 37 °C while the soluble enzyme lost nearly 40% of the initial activity under similar incubation conditions. Immobilized bitter gourd peroxidase preparation appeared to be more rigid to proteolysis mediated by trypsin compared with soluble bitter gourd peroxidase. Copyright © 2004 Society of Chemical Industry
Effects of supplementation of succinic acid on the production and molecular weight distribution of exopolysaccharides by Antrodia camphorata in batch cultures
Authors: Shu Chin‐Hang , Lung Ming‐Yeou , Xu Chun‐Jun 
Published: December 2004

AbstractThe effects of organic acid supplementation on both yields and molecular weight distributions of exopolysaccharide (EPS) of Antrodia camphorata were investigated in shaker flasks and air‐lift bioreactors. In the shaker flask study, five out of six organic acid‐supplemented cultures showed negative effects on cell growth, the exception being pyruvic acid‐supplemented culture; lower number average molecular weights (Mn) of EPS were obtained in all the supplemented cultures. EPS production was enhanced by 31% due to the addition of succinic acid. Optimum product yield was obtained between 2.0 and 3.0 g dm−3 succinic acid; however, the specific production of EPS increased monotonically as succinic acid concentration was increased from 0 to 5 g dm−3. Enhancement of EPS yield by 28% and a higher Mn of EPS (around 310 kDa) due to the addition of succinic acid were also demonstrated in an air‐lift bioreactor. In addition, a novel fermentation process resistant to EPS degradation is proposed, based on the inhibition of β‐glucanase activity by the supplementation with succinic acid. Copyright © 2004 Society of Chemical Industry
Effects of anions on the photocatalytic and photoelectrocatalytic degradation of reactive dye in a packed‐bed reactor
Authors: Zhang Wenbing , An Taicheng , Cui Mingchao , Sheng Guoying , Fu Jiamo 
Published: December 2004

AbstractThe effects of various anions, Cl−, ClO4−, SO42−, NO3−, HCO3−, H2PO4− and C2O42−, on the photocatalytic and photoelectrocatalytic degradation of reactive Brilliant Orange K‐R have been investigated in a packed‐bed photoelectrocatalytic reactor. It was found that the nature and concentrations of these inorganic anions significantly affected the photocatalytic and photoelectrocatalytic degradation performance of the reactive dye. The results indicated that the external electric field was successfully applied to improve the photocatalytic efficiency of reactive Brilliant Orange K‐R in the presence of Cl−, especially at higher concentrations, while other inorganic anions displayed more or less negative effects on the degradation of the dye. The strongest inhibition effect on photocatalytic and photoelectrocatalytic degradation of the dye was observed in the presence of HCO3− ions. Copyright © 2004 Society of Chemical Industry
An hp‐adaptive finite element method for scattering problems in computational electromagnetics
Authors: Rachowicz W. , Zdunek A. 
Published: December 2004

AbstractAn hp‐adaptive finite element (FE) approach is presented for a reliable, efficient and accurate solution of 3D electromagnetic scattering problems. The radiation condition in the far field is satisfied automatically by approximation with infinite elements (IE). Near optimal discretizations that can effectively resolve local rapid variations in the scattered field are sought adaptively by mesh refinements blended with graded polynomial enrichments. The p‐enrichments need not be spatially isotropic. The discretization error can be controlled by a self‐adaptive process, which is driven by implicit or explicit a posteriori error estimates. The error may be estimated in the energy norm or in a quantity of interest. A radar cross section (RCS) related linear functional is used in the latter case. Adaptively constructed solutions are compared to pure uniform p approximations. Numerical, highly accurate, and fairly converged solutions for a number of generic problems are given and compared to previously published results. Copyright © 2004 John Wiley & Sons, Ltd.
Multiscale enrichment based on partition of unity
Authors: Fish Jacob , Yuan Zheng 
Published: December 2004

AbstractA new multiscale enrichment method based on the partition of unity (MEPU) method is presented. It is a synthesis of mathematical homogenization theory and the partition of unity method. Its primary objective is to extend the range of applicability of mathematical homogenization theory to problems where scale separation may not be possible. MEPU is perfectly suited for enriching the coarse scale continuum descriptions (PDEs) with fine scale features and the quasi‐continuum formulations with relevant atomistic data. Numerical results show that it provides a considerable improvement over classical mathematical homogenization theory and quasi‐continuum formulations. Copyright © 2005 John Wiley & Sons, Ltd.
Acremonium pyomyositis in a pediatric patient with acute leukemia
Authors: Chang Yu‐Hsiang , Huang Li‐Min , Hsueh Po‐Ren , Hsiao Cheng‐Hsiang , Peng Shinn‐Forng , Yang Rong‐Sen , Lin Kai‐Hsin 
Published: December 2004

AbstractInvasive Acremonium infection in humans is rare. We report a patient with leukemia who developed pyomyositis due to Acremonium species. Painful cutaneous nodules and severe myalgia were the first clinical manifestations during the neutropenic stage after chemotherapy. Magnetic resonance image (MRI) revealed multiple nodular lesions scattered along the intramuscular regions of the lower legs. Culture of an aspiration grew Acremonium species. Surgical drainage was performed. Although all antifungal agents tested showed no in vitro inhibitory activity, we successfully treated this patient with amphotericin B, granulocyte colony‐stimulating factor (G‐CSF), and surgical drainage. © 2004 Wiley‐Liss, Inc.
Rheology and gelation kinetics in laponite dispersions containing poly(ethylene oxide)
Authors: Baghdadi Hossein A. , Sardinha Heidi , Bhatia Surita R. 
Published: December 2004

AbstractWe report results on the rheology of a model polymer/clay system, laponite clay particles with added poly(ethylene oxide) (PEO), focusing on the kinetics of gel formation and on molecular weight effects. We examined solutions at both pH = 7, where interparticle attractions are present and a networked gel is formed; and at pH = 10, where repulsive forces dominate and laponite forms a colloidal glass. We found that PEO of low to moderate molecular weight significantly slows down gelation and decreases the complex viscosity and elastic modulus of the dispersion by several orders of magnitude for both pH = 7 and 10. In the former case, adsorbed PEO likely forms a steric barrier to the formation of an attractive gel. In the latter case, we propose that free PEO chains in solution induce a depletion attraction between particles, preventing or slowing the formation of a colloidal glass. At higher molecular weights, PEO chains are long enough to bridge between particles and form an associative network, enhancing the viscosity and elastic modulus for both pH = 7 and 10. Finally, we have shown the critical molecular weight for transitioning between these two types of behavior scales with the interparticle distance. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 233–240, 2005