bluuebunny/crossref_metadata_2025_split huggingface dataset:
Power of direct vs. indirect haplotyping in association studies
Authors: Thomas Stuart , Porteous David , Visscher Peter M. 
Published: January 2004

AbstractHaplotype analysis is essential to studies of the genetic factors underlying human disease, but requires a large sample size of phase‐known data. Recently, directly haplotyping individuals was suggested as a means of maximizing the phase‐known data from a sample. Haplotyping, however, is much more labor‐intensive than indirectly inferring haplotypes from genotypes (genotyping). This study uses simulations to compare the power of each methodology to detect associations between a haplotype and a trait or disease locus under conditions of varying linkage disequilibrium. The relative power of haplotyping over genotyping in association studies increases with decreasing sample size, decreasing linkage disequilibrium, decreasing numbers of marker loci, and decreasing numbers of different haplotypes. In addition, the frequency of the haplotype of interest and the magnitude of its association with the disease affect the power. From a cost‐benefit standpoint, genotyping would be favored with large multiplicative risks (relative risk of haplotype >2.5). If case numbers are limiting rather than cost, haplotyping would maximize the information obtained. At small haplotype frequencies (e.g., <0.05), haplotyping is relatively more efficient, but there is little absolute power to detect associations under either methodology. Given the much larger laboratory resources required for direct haplotyping, genotyping would probably be favored under most conditions, but this must be balanced against the unit costs associated with recruitment and phenotyping. In the context of multipurpose, prospective cohort studies (e.g., the UK Biobank study), there may be a general value in establishing a series of directly haplotyped individuals to serve as controls for a number of alternative studies.Genet Epidemiol26:116–124, 2004. © 2004 Wiley‐Liss, Inc.
A trisomic transmission disequilibrium test
Authors: Xu Zhiying , Kerstann Kimberly F. , Sherman Stephanie L. , Chakravarti Aravinda , Feingold Eleanor 
Published: January 2004

AbstractCertain congenital disorders that are rare in the general population are quite common in individuals with trisomic conditions. For example, complete atrioventricular septal defect occurs in about 20% of individuals with Down syndrome, an approximately 500‐fold increase in risk as compared to individuals without Down syndrome. Genetic variation on the chromosome involved in the trisomy may affect susceptibility to these trisomy‐specific disorders. That is, increased dosage of a variant may be directly involved in increasing the risk of a disorder, or it may be indirectly involved by causing up‐ or downregulation of other genes. As in standard disomic gene‐mapping, one can search for genes using linkage or association methods. Within association methods, one can consider case‐control methods or family‐based control methods such as the transmission disequilibrium test (TDT). Most gene‐mapping methods need to be substantially redesigned for use with trisomic data. In this paper, we present a “trisomic TDT”, a statistical method of testing for nonrandom transmission of alleles from parents to trisomic children. We demonstrate the method on a dataset of parent‐child trios in which the child has Down syndrome. Genet Epidemiol 26:125–131, 2004. © 2004 Wiley‐Liss, Inc.
Conditional multipoint linkage analysis using affected sib pairs: An alternative approach
Authors: Chiu Yen‐Feng , Liang Kung‐Yee 
Published: January 2004

AbstractRecently, Liang et al. ([2001b] Genet. Epidemiol. 21:105–122) proposed a conditional approach to assess linkage evidence on the target region by incorporating linkage information from an unlinked (reference) region using allele shared IBD (identity‐by‐decent) from affected sib pairs. This is carried out by conditioning on the IBD sharing value at the estimated trait locus of the reference region. Since markers considered are typically non‐fully informative, the IBD sharing at each marker needs to be estimated (or imputed). In this report, we propose an alternative approach to deal with the IBD sharing in the reference region. This new approach makes full use of the observed data without having to categorize the imputed IBD sharing as needed in Liang et al. ([2001b] Genet. Epidemiol. 21:105–122). We compare these two approaches by simulating data from a variety of two‐locus models including heterogeneity, additive and multiplicative with either fully informative markers or non‐fully informative markers. The performance of both approaches is quite comparable showing consistent estimates of the trait locus and key genetic parameters. Genet Epidemiol 26:108–115, 2004. © 2004 Wiley‐Liss, Inc.
Using simulation‐based inference with panel data in health economics
Authors: Contoyannis Paul , Jones Andrew M. , Leon‐Gonzalez Roberto 
Published: January 2004

AbstractPanel datasets provide a rich source of information for health economists, offering the scope to control for individual heterogeneity and to model the dynamics of individual behaviour. However the qualitative or categorical measures of outcome often used in health economics create special problems for estimating econometric models. Allowing a flexible specification of the autocorrelation induced by individual heterogeneity leads to models involving higher order integrals that cannot be handled by conventional numerical methods. The dramatic growth in computing power over recent years has been accompanied by the development of simulation‐based estimators that solve this problem. This review uses binary choice models to show what can be done with conventional methods and how the range of models can be expanded by using simulation methods. Practical applications of the methods are illustrated using data on health from the British Household Panel Survey (BHPS). Copyright © 2003 John Wiley & Sons, Ltd.
Does problem drinking affect employment? Evidence from England
Authors: MacDonald Ziggy , Shields Michael A. 
Published: January 2004

AbstractIn this paper, we use data from the Health Survey of England to show that problem drinking is negatively and significantly associated with the probability of being in work, once the endogenous relationship between these outcomes is accounted for. Being a problem drinker leads to a substantial reduction in the probability of working by between 7 and 31%, the former figure being roughly equivalent to the positive effect of having a degree relative to no qualifications in our data. This finding is robust to a variety of identifying restrictions and definitions of problem drinking. Moreover, we find that problem drinking defined by the observed psychological and physical symptoms of alcohol is an important predictor of employment, and allows for the fact that individuals differ in their tolerance or susceptibility to alcohol. Our results suggest that there may be important labour market benefits from public health policies aimed at the prevention and treatment of problem drinking. Copyright © 2003 John Wiley & Sons, Ltd.
Real exchange rate fluctuations and monetary shocks: a revisit
Authors: Chen Shiu‐Sheng 
Published: January 2004

AbstractIn this paper, I first estimate a structural VAR model by following Clarida and Gali (1994) and obtain results indicating that the variance of real exchange rates can be attributed more to monetary shocks when the sample span is extended. In order to further investigate this aspect, I then employ a VAR model with long‐run US–UK annual data from 1889 to 1995. According to the variance decompositions, I find that monetary shocks can explain nearly 50% of real exchange rate variance in the long‐run sample periods. All the evidence suggests that monetary shocks are indeed more important in a larger sample set. Copyright © 2003 John Wiley & Sons, Ltd.
Do higher solvency ratios reduce the costs of bailing out insured banks?
Authors: Eastwood Robert K. 
Published: January 2004

AbstractThe relationship between solvency constraints and bank behaviour in the presence of fixed rate deposit insurance is investigated. A rise in the minimum solvency ratio does not necessarily reduce the adverse consequences of moral hazard: bank efficiency may fall and expected bailout costs may rise. Such outcomes are possible even if credit risk is purely systemic. Similar results obtain in respect of level increases in bank capital, tangible or intangible, although in this case purely systemic risk excludes perverse outcomes. Copyright © 2003 John Wiley & Sons, Ltd.
Inflation targeting or fear of floating in disguise: the case of Mexico
Authors: Ball Christopher P. , Reyes Javier 
Published: January 2004

AbstractThis paper uses simple analytics to show the similarities and differences between inflation targeting and fear of floating in emerging markets. The analytics provide well‐defined predictions for the behaviour of exchange rates and relevant monetary variables under both regimes. This allows us to distinguish clearly one regime from another and empirically test whether or not a country that targets inflation also exhibits a fear of floating.We analyse the recent experience in Mexico where the authorities now claim to be following an inflation targeting regime. Mexico is also one of the countries claimed to exhibit a fear of floating. Using data from Banco de México, we first confirm that by standard measures Mexico exhibits fear of floating. Second, we show that Mexico is inflation targeting and discuss the relationship and test for a distinction between the two. Finally, we conclude by discussing our results and their implications for other emerging market inflation targeters. Copyright © 2004 John Wiley & Sons, Ltd.
Transmission of equity returns and volatility in Asian developed and emerging markets: a multivariate GARCH analysis
Authors: Worthington Andrew , Higgs Helen 
Published: January 2004

AbstractThis paper examines the transmission of equity returns and volatility among Asian equity markets and investigates the differences that exist in this regard between the developed and emerging markets. Three developed markets (Hong Kong, Japan and Singapore) and six emerging markets (Indonesia, Korea, Malaysia, the Philippines, Taiwan and Thailand) are included in the analysis. A multivariate generalized autoregressive conditional heteroskedasticity (MGARCH) model is used to identify the source and magnitude of spillovers. The results generally indicate the presence of large and predominantly positive mean and volatility spillovers. Nevertheless, mean spillovers from the developed to the emerging markets are not homogeneous across the emerging markets, and own‐volatility spillovers are generally higher than cross‐volatility spillovers for all markets, but especially for the emerging markets. Copyright © 2003 John Wiley & Sons, Ltd.
Can regime‐switching models reproduce the business cycle features of US aggregate consumption, investment and output?
Authors: Clements Michael P. , Krolzig Hans‐Martin 
Published: January 2004

AbstractThe ability of Markov‐switching (MS) autoregressive models to replicate selected classical business cycle features found in US post‐war consumption, investment and output is compared to that of linear models. Univariate MS models appear to offer more dynamically parsimonious representations, but generally are unable to reproduce features missed by linear models. In the multivariate models, some cointegration restrictions were found to have a crucial impact, and the ability of models that imposed cointegration to reproduce business cycle features was enhanced by Markov switching. Copyright © 2004 John Wiley & Sons, Ltd.
International real interest rate differentials, purchasing power parity and the behaviour of real exchange rates: the resolution of a conundrum
Authors: Taylor Mark P. , Sarno Lucio 
Published: January 2004

AbstractAccording to one strand of the international finance literature, market efficiency implies that the real exchange rate follows a martingale process, in direct conflict with the long‐run absolute purchasing power parity hypothesis, which requires a stationary real exchange rate process. This conflict between market efficiency and long‐run PPP appears as something of a conundrum. We resolve this conundrum by relaxing the assumption of a constant real interest rate differential and analysing the vector equilibrium correction system linking prices and the exchange rate, and draw out the economic intuition of our result. Copyright © 2004 John Wiley & Sons, Ltd.
Bone regeneration in rabbit sinus lifting associated with bovine BMP
Authors: Allegrini Sergio , Yoshimoto Marcelo , Salles Marcos B. , König Bruno 
Published: January 2004

AbstractAutogenous bone is considered the optimal grafting material for sinus lifting, although its harvesting causes great patient discomfort. Various approaches have been taken in order to obtain sinus lifting with preexisting tissue. However, because of the unsuitability of such tissue, additional materials have been required. Alternatively, biomaterials from humans or other animals are used. In this study, the efficacy of using morphogenetic bovine bone protein (BMPb) to augment the maxillary sinus floor was examined. Four grafting materials were employed: lyophilized bovine bone powder, absorbable collagen flakes, natural hydroxylapatite, and synthetic hydroxylapatite. Two groups of rabbits were studied. In one group, graft material only was used. In the other, graft material was combined with 0.5 mg BMPb. During 8 weeks of observation, polyfluorochrome tracers were injected in subcutaneous tissue to evaluate new bone‐ deposition periods. Following sacrifice, the samples were examined under fluorescent and light microscopes. Results indicated 33.34% more newly formed bone in BMPb animals than in controls. Graft‐material resorption increased, but natural HA showed no significant alterations. The results show that the use of BMPb, although providing osteoinduction, might not promote sufficient bone formation. Nonetheless, this material could provide an alternative to autogenous grafts, thereby avoiding patient discomfort. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 127–131, 2004
Segmented detachable structure of cochlear‐implant electrodes for close‐hugging engagement with the modiolus
Authors: Mirzadeh H. , Abbasi F. 
Published: January 2004

AbstractSurface and bulk modification techniques of polydimethylsiloxane (PDMS) polymers were used to develop a new intracochlear electrode that can closely hug the inner wall of scala tympani. Laser‐induced surface grafting of poly (2‐hydroxyethyl methacrylate) (PHEMA) and sequential method for preparation of interpenetrating polymer networks (IPNs) of PDMS/PHEMA were, respectively, used for surface and bulk modifications. The hydrogel content and water‐uptake capability of the modified samples were optimized by Taguchi method for experimental design. The modified PDMS samples were examined by performing attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy, water contact‐angle measurement, and peel strength tests. The performances of actual‐sized fabricated electrodes were assessed inside a transparent model of scala tympani, which was filled with saline. After a swelling process, the hydrophilic branch begins to elongate and detach from hydrophobic branch and pushes it toward the inner wall. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 191–198, 2004
SEM/EDS evaluation of porcelain adherence to gold‐coated cast titanium
Authors: Lee K. M. , Cai Z. , Griggs J. A. , Guiatas L. , Lee D. J. , Okabe T. 
Published: January 2004

AbstractThe adhesion between titanium and dental porcelain is related to the diffusion of oxygen to the reaction layer formed on cast‐titanium surfaces during porcelain firing. The diffusion of oxygen could be suppressed by coating the titanium surface with a thin gold layer. This study characterized the effects of gold coating on titanium–ceramic adhesion. ASTM grade II CP titanium was cast into a MgO‐based investment (Selevest CB, Selec). The specimen surfaces were air abraded with 110‐μm Al2O3 particles. Gold coating was applied on titanium surfaces by three methods: gold‐paste (Deck Gold NF, Degussa‐Ney) coating and firing at 800 °C for three times, single gold‐paste coating and firing followed by sputter coating (40 mA, 500 s), and sputter coating (40 mA, 1000 s). Surfaces only air abraded with Al2O3 particles were used as controls. An ultra‐low‐fusing dental porcelain (Vita Titankeramik, Vident) was fused on titanium surfaces. Specimen surfaces were characterized by SEM/EDS and XRD. The titanium–ceramic adhesion was evaluated by a biaxial flexure test (N = 8), and area fraction of adherent porcelain (AFAP) was determined by EDS. Numerical results were statistically analyzed by one‐way ANOVA and the Student‐Newman‐Keuls test at α = 0.05. SEM fractography showed a substantial amount of porcelains remaining on the gold‐sputter‐coated titanium surfaces. A new Au2Ti phase was found on gold‐coated titanium surface after the firing. Significantly higher (p < .05) AFAP values were determined for the gold‐sputter‐coated specimens compared to the others. No significant differences were found among the other groups and the control. Results suggested that gold coatings used in this study are not effective barriers to completely protect titanium from oxidation during the porcelain firing, and porcelain adherence to cast titanium can be improved by gold‐sputter coating used in the present study. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 165–173, 2004
Effect of post‐processing heat treatment on the fracture strength of a heat‐pressed dental ceramic
Authors: Denry I. L. , Holloway J. A. 
Published: January 2004

AbstractThe purpose of this study was to evaluate the effect of post‐processing heat treatment on the fracture strength of a heat‐pressed lithium disilicate dental ceramic (OPC 3G). Bar‐shaped wax patterns (2 × 4 × 22 mm; n = 60) were invested and heat pressed in an automated pressing machine according to manufacturer's recommendations. The bars were polished to 1200 grit and annealed at 600 °C for 1 h. Two groups were left untreated as controls, one of which was Vickers indented in oil prior to testing in three‐point bending. Two groups were indented and then heat treated at either 800 or 825 °C for 30 min. The corresponding control groups were heat treated, then indented prior to testing. Optical micrographs of the indentations were taken before and after heat treatment under differential interference contrast. The fracture toughness and/or fracture strength of the specimens was determined by the indentation‐strength technique in three‐point bending. Indentation‐generated cracks were not discernible by optical microscopy after heat treatment at either 800 or 825 °C for 30 min, even under 1000 × magnification. ANOVA and Tukey's test showed that heat treatment in air at 825 °C for 30 min significantly increased the fracture strength of a heat‐pressable lithium disilicate ceramic. This result was attributed to healing of the flaws present in the material. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 174–179, 2004
Effects of the initial temperature of acrylic bone cement liquid monomer on the properties of the stem–cement interface and cement polymerization
Authors: Iesaka K. , Jaffe W. L. , Kummer F. J. 
Published: January 2004

AbstractIt has been shown that preheating the femoral stem prior to insertion minimizes interfacial porosity at the stem–cement interface. In this study, the effects of methylmethacrylate monomer temperature prior to mixing on the properties of stem–cement interface and cement polymerization were evaluated for 4 °C, room temperature, and 37 °C using a test model and cementing techniques that simulated a clinical situation. The nature and extent of interfacial porosity of stem–cement interface was quantified, the static shear strength of the stem–cement interface determined, and the time and temperature of polymerization at the cement–bone interface were measured. Compared to RT monomer, preheating monomer to 37 °C produced higher polymerization temperatures and greater initial interfacial shear strength with an unchanged amount of interfacial porosity. Precooling monomer to 4 °C produced lower polymerization temperatures and decreased initial interfacial shear strength, with the amount of interfacial porosity unchanged compared to the RT group. Although clinical techniques of preheating or precooling bone cement have some effects on the properties of the stem–cement interface and cement polymerization, they do not appear to enhance implant fixation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 186–190, 2004
Change of properties during storage of a UDMA/TEGDMA dental resin
Authors: Lee Jong Keun , Choi Joo‐Yeol , Lim Bum‐Soon , Lee Yong‐Keun , Sakaguchi Ronald L. 
Published: January 2004

AbstractThe aim of this study was to evaluate the changes in viscoelastic properties of a UDMA‐based dental resin as a function of time after initial light exposure. Specimens of a UDMA/TEGDMA (70:30 wt%) resin were irradiated by a visible‐light‐curing unit. Immediately after the irradiation, the light‐cured specimen was stored in the dark for different times from 1 to 120 h at 37 °C, and characterized by means of DMA, DSC, and FTIR spectroscopy. The irradiated specimen exhibited a bimodal shape in the form of two rapid declines in log E′ corresponding to glass transition with a plateau between the two declines. Two distinct peaks were seen in tan δ versus temperature. The thermal reaction of the incompletely cured sample with residual groups trapped by the fast reaction during irradiation is responsible for the plateau. After storage, significant changes were observed in dynamic mechanical parameters, DSC exotherm, and degree of conversion. Storage modulus continued to increase during the 4 h of storage and leveled off thereafter. Peak heights of tan δ versus temperature were also influenced by storage. Degree of conversion increased from 75 ± 2% immediately after irradiation to 87 ± 3% after 120 h storage. The changes of the properties of this dental resin system when stored at 37 °C after irradiation are clinically important in terms of stability, durability, and performance after initial polymerization. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 216–221, 2004
Some New uniform frames with block size four and index one or three
Authors: Ge Gennian , Lam C.W.H. , Ling Alan C.H. 
Published: January 2004

AbstractIn this paper, some new uniform frames with block size four and index one or three are obtained. The known existence results for (4,1)‐frames and (4,3)‐frames are both improved to the extent that only a finite number of possible exceptions remain. © 2003 Wiley Periodicals, Inc.
On optimal superimposed codes
Authors: Kim Hyun Kwang , Lebedev Vladimir 
Published: January 2004

AbstractA (w,r) cover‐free family is a family of subsets of a finite set such that no intersection of w members of the family is covered by a union of r others. A binary (w,r) superimposed code is the incidence matrix of such a family. Such a family also arises in cryptography as a concept of key distribution patterns. In this paper, we develop a method of constructing superimposed codes and prove that some superimposed codes constructed in this way are optimal. © 2003 Wiley Periodicals, Inc. J Combin Designs 12: 79–71, 2004.
Some Hadamard matrices of order 32 and their binary codes
Authors: Araya Makoto , Harada Masaaki , Kharaghani Hadi 
Published: January 2004

AbstractIt is known that all doubly‐even self‐dual codes of lengths 8 or 16, and the extended Golay code, can be constructed from some binary Hadamard matrix of orders 8, 16, and 24, respectively. In this note, we demonstrate that every extremal doubly‐even self‐dual [32,16,8] code can be constructed from some binary Hadamard matrix of order 32. © 2004 Wiley Periodicals, Inc.