bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Problems on a One-Dimensional Correlated Random Walk with Various Types of Barrier
Authors: Zhang Yuan Lin
Published: April 2006

In this paper one-dimensional correlated random walks (CRW) with various types of barrier such as elastic barriers, absorbing barriers and so on are defined, and explicit expressions are derived for the ultimate absorbing probability and expected duration. Some numerical examples to illustrate the effects of correlation are also presented.
Some new results on queueing networks with batch movement
Authors: Henderson W. , Taylor P. G.
Published: April 2006

Product-form equilibrium distributions in networks of queues in which customers move singly have been known since 1957, when Jackson derived some surprising independence results. A product-form equilibrium distribution has also recently been shown to be valid for certain queueing networks with batch arrivals, batch services and even correlated routing.

This paper derives the joint equilibrium distribution of states immediately before and after a batch of customers is released into the network. The results are valid for either discrete- or continuous-time queueing networks: previously obtained results can be seen as marginal distributions within a more general framework. A generalisation of the classical ‘arrival theorem' for continuous-time networks is given, which compares the equilibrium distribution as seen by arrivals to the time-averaged equilibrium distribution.
Equality of critical densities in continuum percolation
Authors: Meester Ronald
Published: April 2006

Consider a homogeneous Poisson process inwith density ρ, and add the origin as an extra point. Now connect any two pointsxandyof the process with probabilityg(x − y), independently of the point process and all other pairs, wheregis a function which depends only on the Euclidean distance betweenxandy, and which is nonincreasing in the distance. We distinguish two critical densities in this model. The first is the infimum of all densities for which the cluster of the origin is infinite with positive probability, and the second is the infimum of all densities for which the expected size of the cluster of the origin is infinite. It is known that if, then the two critical densities are non-trivial, i.e. bounded away from 0 and ∞. It is also known that ifgis of the form, for somer > 0, then the two critical densities coincide. In this paper we generalize this result and show that under the integrability condition mentioned above the two critical densities are always equal.
Optimal timing of antiviral therapy in HIV infection
Authors: Berman Simeon M.
Published: April 2006

A three-stage real diffusion process is used as a model of the T-cell count of an HIV-positive individual who is to receive antiviral therapy such as AZT. The ‘quality of life' of such a person is identified as the sojourn time of the diffusion process above a certain critical T-cell level c. The time of introducing therapy is defined as the first-passage time of the diffusion to a prescribed level z > c. The distribution of the sojourn time of the diffusion above the level c depends on the level z at which therapy is initiated. The expected sojourn time is explicitly computed as a function of z for the particular diffusion process defining the model. There is a simple criterion for determining when to start therapy as early as possible.
Poisson approximations for the distribution and moments of orderedm-spacings
Authors: Glaz Joseph , Naus Joseph , Roos Malgorzata , Wallenstein Sylvan
Published: April 2006

This article investigates the accuracy of approximations for the distribution of ordered m-spacings for i.i.d. uniform observations in the interval (0, 1). Several Poisson approximations and a compound Poisson approximation are studied. The result of a simulation study is included to assess the accuracy of these approximations. A numerical procedure for evaluating the moments of the ordered m-spacings is developed and evaluated for the most accurate approximation.
Spatial epidemics with large finite range
Authors: Penrose Mathew D.
Published: April 2006

In the epidemic with removal with range r, each site z, once infected, remains so for a period of time Tz, the variables Tz being i.i.d. with mean μ. While infected, a site infects its healthy r-neighbours independently at total rate α. After infection, sites become immune. We show that the critical rate of infection αc (r), above which an epidemic starting from a single site may continue forever, converges to μ–1 as r →∞.
The minimax bookie
Authors: Barry Daniel , Hartigan John A.
Published: April 2006

A bookmaker makes a book on a horse race: he offers odds against the various horses winning the race, and gamblers accept bets at those odds when they find the odds attractive. The book at a particular time consists of the bookmaker's winnings according to the different outcomes of the race if the race were run at that time. We consider strategies the bookmaker might adopt when deciding how to alter his quoted odds as bets accumulate. The bookmaker is assumed to behave conservatively in the sense that he tries to minimise his expected maximum loss over all possible outcomes of the race.
On a distributional bound arising in autoregressive model fitting
Authors: Papangelou F.
Published: April 2006

In the theory of autoregressive model fitting it is of interest to know the asymptotic behaviour, for large sample size, of the coefficients fitted. A significant role is played in this connection by the moments of the norms of the inverse sample covariance matrices. We establish uniform boundedness results for these, first under generally weak conditions and then for the special case of (infinite order) processes. These in turn imply corresponding ergodic theorems for the matrices in question.
An M/G/1 queue with multiple types of feedback and gated vacations
Authors: Boxma Onno J. , Yechiali Uri
Published: April 2006

This paper considers a single-server queue with Poisson arrivals and multiple customer feedbacks. If the first service attempt of a newly arriving customer is not successful, he returns to the end of the queue for another service attempt, with a different service time distribution. He keeps trying in this manner (as an ‘old' customer) until his service is successful. The server operates according to the ‘gated vacation' strategy; when it returns from a vacation to find K (new and old) customers, it renders a single service attempt to each of them and takes another vacation, etc. We study the joint queue length process of new and old customers, as well as the waiting time distribution of customers. Some extensions are also discussed.
Exact aggregation of absorbing Markov processes using the quasi-stationary distribution
Authors: Ledoux James , Rubino Gerardo , Sericola Bruno
Published: April 2006

We characterize the conditions under which an absorbing Markovian finite process (in discrete or continuous time) can be transformed into a new aggregated process conserving the Markovian property, whose states are elements of a given partition of the original state space. To obtain this characterization, a key tool is the quasi-stationary distribution associated with absorbing processes. It allows the absorbing case to be related to the irreducible one. We are able to calculate the set of all initial distributions of the starting process leading to an aggregated homogeneous Markov process by means of a finite algorithm. Finally, it is shown that the continuous-time case can always be reduced to the discrete one using the uniformization technique.
Regenerative rare events simulation via likelihood ratios
Authors: Asmussen Søren , Rubinstein Reuven Y. , Wang Chia-Li
Published: April 2006

In this paper we obtain some new theoretical and numerial results on estimation of small steady-state probabilities in regenerative queueing models by using the likelihood ratio (score function) method, which is based on a change of the probability measure. For simple GI/G/1 queues, this amounts to simulating the regenerative cycles by a suitable change of the interarrival and service time distribution, typically corresponding to a reference traffic intensity ρ0 which is < 1 but larger than the given one ρ. For the M/M/1 queue, the resulting gain of efficiency is calculated explicitly and shown to be considerable. Simulation results are presented indicating that similar conclusions hold for gradient estimates and in more general queueing models like queueing networks.
Recursive relations for the distribution of waiting times in a Markov chain
Authors: Banjevic Dragan
Published: April 2006

A Markov chain is used as a model for a sequence of random experiments. The waiting time for sequence patterns is considered. Recursive-type relations for the distribution of waiting times are obtained.
The final outcome and temporal solution of a carrier-borne epidemic model
Authors: Ball Frank , Clancy Damian
Published: April 2006

We consider a stochastic model for the spread of a carrier-borne epidemic amongst a closed homogeneously mixing population, in which a proportion 1 − π of infected susceptibles are directly removed and play no part in spreading the infection. The remaining proportion π become carriers, with an infectious period that follows an arbitrary but specified distribution. We give a construction of the epidemic process which directly exploits its probabilistic structure and use it to derive the exact joint distribution of the final size and severity of the carrier-borne epidemic, distinguishing between removed carriers and directly removed individuals. We express these results in terms of Gontcharoff polynomials. When the infectious period follows an exponential distribution, our model reduces to that of Downton (1968), for which we use our construction to derive an explicit expression for the time-dependent state probabilities.
On a generalization of the ehrenfest urn model
Authors: Dette Holger
Published: April 2006

Krafft and Schaefer [14] considered a two-parameter Ehrenfest urn model and found the n-step transition probabilities using representations by Krawtchouk polynomials. For a special case of the model Palacios [17] calculated some of the expected first-passage times. This note investigates a generalization of the two-parameter Ehrenfest urn model where the transition probabilities pi,i+1 and pi,i+1 are allowed to be quadratic functions of the current state i. The approach used in this paper is based on the integral representations of Karlin and McGregor [9] and can also be used for Markov chains with an infinite state space.
On the validity of Wald's equation
Authors: Roters Markus
Published: April 2006

In this paper we review conditions under which Wald's equation holds, mainly if the expectation of the given stopping time is infinite. As a main result we obtain what is probably the weakest possible version of Wald's equation for the case of independent, identically distributed (i.i.d.) random variables. Moreover, we improve a result of Samuel (1967) concerning the existence of stopping times for which the expectation of the stopped sum of the underlying i.i.d. sequence of random variables does not exist. Finally, we show by counterexamples that it is impossible to generalize a theorem of Kiefer and Wolfowitz (1956) relating the moments of the supremum of a random walk with negative drift to moments of the positive part of X1 to the case where the expectation of X1 is —∞. Here, the Laplace–Stieltjes transform of the supremum of the considered random walk plays an important role.
Multivariate Bonferroni-type lower bounds
Authors: Chen Tuhao , Seneta E.
Published: April 2006

We derive multivariate Sobel–Uppuluri–Galambos-type lower bounds for the probability that at least a1 and at least a2, and for the probability that exactly a1 and a2, out of n and N events, occur. The lower bound presented here reduces to a sharper bound than that of Galambos and Lee (1992). Our approach is by way of indicator functions and bivariate binomial moments. A new concept, marginal Bonferroni summation, is introduced in this paper.
Strong convergence of proportions in a multicolor Pólya urn
Authors: Gouet Raúl
Published: April 2006

We prove strong convergence of the proportions Un/Tn of balls in a multitype generalized Pólya urn model, using martingale arguments. The limit is characterized as a convex combination of left dominant eigenvectors of the replacement matrix R, with random Dirichlet coefficients.
Overview of Safety Pharmacology
Authors: Porsolt Roger D.
Published: April 2006

Safety pharmacology assesses the potential risks of novel pharmaceuticals for human use. ICH S7A guidelines recommend a core battery of studies on three vital systems: central nervous system (CNS), cardiovascular (CV) and respiratory. Primary CNS studies look for effects on general behavior, locomotion, neuromuscular coordination, the convulsive threshold, and vigilance. The primary CV test battery evaluates proarrhythmic risk using in vitro approaches (hERG channel and Purkinje fiber assays) and in vivo measurements in conscious animals via telemetry. Comprehensive cardiac risk assessment also includes full hemodynamic evaluation, most suitably conducted in the anesthetized large animal. Basic respiratory function can be approached via whole‐body plethysmography in conscious animals where sensitivity to respiratory‐depressant effects can be enhanced by exposure to increased CO2. Other aspects of safety pharmacology studies discussed are the timing of studies, ethical and animal welfare issues, and statistical evaluation.
An Overview of RNA Structure Prediction and Applications to RNA Gene Prediction and RNAi Design
Authors: Stormo Gary D.
Published: April 2006

This unit briefly describes the two fundamentally different methods for predicting RNA structures. The first is to find that structure with the minimum free energy of folding, as predicted by various thermodynamic parameters related to base‐pair stacking, loop lengths, and other features. If one has only a single sequence, this thermodynamic approach is the best available method. The second fundamental approach to RNA structure prediction is to use multiple, homologous sequences for which one can infer a common structure, and then try and predict a structure common to all of the sequences. Such an approach is referred to as a comparative method or phylogenetic method of RNA structure prediction.
An experimental assessment of the potential impacts of longline mussel farming on the infauna in an open coastal embayment
Authors: Lasiak T.A. , Underwood A.J. , Hoskin M.
Published: April 2006

The existence of perceived ecological impacts and development of adaptive management solutions to mitigate these problems are important issues in sustainable aquaculture. This paper examines the general impacts of two newly established trial longline installations on the infauna in Twofold Bay, a large, coastal embayment in south‐east Australia.

We hypothesized that the physical presence of these longline installations and the biological activities of the mussels they supported would result in temporal changes in densities of infaunal taxa below installations differing from those at undisturbed control sites. We also predicted different patterns of variability in infauna between longline and control sites from before to after the longlines were stocked. These hypotheses were tested by using a beyond‐BACI sampling design and asymmetrical analyses of variance to compare changes in densities of taxa at several different spatial scales below the proposed longline sites with those at two adjacent control sites, before and after the longlines were stocked.

After 18 months of longline operations, there was no evidence of any impact on total number of taxa, nor densities of individual taxa. Short‐term temporal trends in densities in plots at control sites from April to May 2001 were often as different from each other as from those at the longline site. This indicates that densities of taxa at the farm site were within the range typically found at undisturbed sites, so there were no ecological impacts from the farm.

These results do not concur with previous studies on impact of mussel farming in semi‐enclosed coastal waters. Differences in location, scale of production, duration of operation and assimilative capacity of the environment probably contributed to this discrepancy. The infauna in Twofold Bay either do not respond to this form of disturbance or have not yet been exposed to disturbance of a sufficient magnitude, or for a sufficient period of time, to elicit a detectable response. Better definition of the potential ecological impacts associated with aquaculture, plus their scale and magnitude in different environments is needed to design experiments and monitoring programmes to detect specific impacts. This activity can only be considered sustainable once we know that these impacts are localized, reversible and short‐term.

Copyright © 2006 John Wiley & Sons, Ltd.
Do I get better looking each day? Changes in self‐perceptions of attractiveness as a function of temporal perspective
Authors: Haddock Geoffrey
Published: April 2006

Do people perceive themselves as becoming more attractive across time? The present studies investigated whether individuals (a) judge their previous self as physically less attractive than their current self and (b) judge their future self to be physically more attractive than their current self. The studies also investigated when temporal biasing of attractiveness is most likely to occur. In Study 1, students rated their present and past attractiveness. The results revealed that participants' ratings of past attractiveness were lower than current ratings, but only among individuals for whom attractiveness was important to their self‐concept. In Study 2, participants rated their present attractiveness and their expected attractiveness in 5 years. The results revealed that ratings of future attractiveness were higher than current ratings, but only among individuals who frequently engage in social comparisons. The implications of the results are discussed with respect to self‐appraisals of attractiveness and psychological well‐being. Copyright © 2006 John Wiley & Sons, Ltd.
Adhesion of composite to enamel and dentin surfaces irradiated by IR laser pulses of 0.5–35 μs duration
Authors: Staninec Michal , Gardner Andrew K. , Le Charles Q. , Sarma Anupama V. , Fried Daniel
Published: April 2006

The characteristics of laser‐treated tooth surfaces depend on the laser wavelength, pulse duration, spatial and temporal laser beam quality, incident fluence, surface roughness, and the presence of water during irradiation. Ablated surfaces are most commonly restored with adhesive dental materials and the characteristics of the ablated surfaces influence adhesion of restorative materials. Previous studies suggest that high bond strengths can be achieved using shorter laser pulses that minimize peripheral thermal damage. In this study, Er:YSGG, Er:YAG, and CO2 lasers were used at irradiation intensities sufficient to simulate efficient clinical caries removal to uniformly irradiate bovine enamel and human dentin surfaces using a motion control system with a microprocessor‐controlled water spray. The degree of spatial overlap of adjacent pulses was varied so as to investigate the influence of irradiation uniformity and surface roughness on the bond strength. Composite resin was bonded to the irradiated surfaces and shear bond tests were used to obtain bond strengths in MPa. The highest results were obtained using the Er:YAG pulses with pulse durations less than 35 μs without the necessity for postirradiation acid etching. Some of these groups were not significantly different from nonirradiated, acid‐etch‐only positive control groups. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Production and characterization of laccase and manganese peroxidase from the ligninolytic fungus Fomes sclerodermeus
Authors: Papinutti Leandro , Martínez María J
Published: April 2006

Fomes sclerodermeus was grown on semi‐defined media based on yeast extract, peptone and glucose (YPG). The fungus produced a minimum basal level of laccase activity irrespective of culture medium. The highest laccase production (20 U cm−3) was obtained in cultures supplemented with CuSO4. Manganese peroxidase (MnP) could only be detected when MnSO4 was added to the medium. None of the aromatic compounds tested stimulated further laccase or MnP production. Laccase and MnP stimulated by Cu2+ or Mn2+ respectively were purified. Two different laccase isoenzymes with the same molecular mass (67 kDa) and N‐linked carbohydrate content (3%) and a slight difference in their pI values (3.41 and 3.48) were characterized. In addition, two different MnP isoenzymes with the same molecular mass (47 kDa) and N‐linked carbohydrate content (4%) and different pI values (3.35 and 3.45) were characterized. Both enzymes showed good stability at 25 °C and over a wide range of pH. Both laccases oxidize ABTS (2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) more efficiently than 2,6‐dimethoxyphenol (DMP) with similar efficiency values (Kcat/Km) while the MnP I, the major peroxidase isoenzyme in the studied conditions, oxidizes the Mn2+ and Mn‐mediated activity on DMP more efficiently than MnP II. Copyright © 2006 Society of Chemical Industry
Excessive, optimal, and insufficient fundraising among the Nonprofit Times 100
Authors: Jacobs Fred A. , Marudas Nicholas P.
Published: April 2006

Using a six‐factor model of donations, we estimate the effect on net donations; i.e., donations less fundraising expenditures, of a one percent marginal increase in fundraising expenditures, for each sample nonprofit organization (NPO) from the Nonprofit Times 100 from 2000 to 2002. No prior study of U.S. NPOs estimates the effect of fundraising expense on net donations. We then use these estimates and what we argue is the correct benchmark, the ratio of fundraising expense to donations, to provide evidence, for each NPO, on whether the NPO's level of fundraising is ‘excessive,’ ‘optimal,’ or ‘insufficient,’ relative to the level that maximizes net donations. All prior studies using log‐log models use what we suggest is an incorrect benchmark for evaluating NPO fundraising behavior.

The estimated effect of a 1% increase in fundraising on net donations varies widely across NPOs in our sample—from an increase in net donations of 0.18% of gross donations to a decrease of 0.66% of gross donations. Of the 76 Nonprofit Times 100 NPOs with usable data in 2002, we estimate that 24 engaged in ‘excessive’ fundraising, 18 engaged in ‘insufficient’ fundraising, and 34 did not engage in ‘excessive’ or ‘insufficient’ fundraising; i.e., we could not reject the null hypothesis of ‘optimal’ levels of fundraising.

Copyright © 2006 John Wiley & Sons, Ltd.
Mathematical modeling and numerical simulation for nucleated solution flow through slit die in foam extrusion
Authors: Stephen C. , Bhattacharya S.N. , Khan A.A.
Published: April 2006

Nucleated solution flow models have been previously developed by Baldwin and coworkers to aid modular design of the foam extrusion process. A framework of previously developed design models is applied here to investigate the flow of nucleated polypropylene–CO2 solution system. Refinement to the design models is introduced through viscosity reduction factors and Redlich‐Kwong equation of state to describe nonideal gas. These models incorporate temperature and concentration dependency of viscosity, surface tension, and solubility. Simulated results of pressure profiles and volumetric flow rates using a power law rheological equation are compared with experimental values from a three pressure tapping slit die. The influence of temperature on the profiles and its effect on design models is discussed. Preliminary results show that temperature plays an important role in the categorization of process design models. POLYM. ENG. SCI., 46:751–762, 2006. © 2006 Society of Plastics Engineers
Characterization of the fracture behavior of polyethylene using measured cohesive curves. II. Variation of cohesive parameters with rate and constraint
Authors: Ting S.K.M. , Williams J.G. , Ivankovic A.
Published: April 2006

The effects of constraint and rate on the measured cohesive parameters are presented. The parameters were extracted from results of an experimental study of the constraint and rate‐dependent fracture behavior of tough polyethylene using circumferentially notched tensile specimens described in a preceding companion paper. The study found that the cohesive parameters, the energy of separation (Γ), the cohesive strength (σpeak), and the break separation (δbreak), are interrelated and no single fracture parameter can be adequately used independently to describe the fracture behavior. POLYM. ENG. SCI., 46:778–791, 2006. © 2006 Society of Plastics Engineers
Electron ionization mass spectra of phosphorus‐containing heterocycles. II. 1,2,3,4,4a,5,6,7,8,8a‐decahydro‐1,3,2‐benzodiazaphosphinine 2‐oxides
Authors: Martiskainen Olli , Juhász Márta , Zalán Zita , Fülöp Ferenc , Pihlaja Kalevi
Published: April 2006

The electron ionization mass spectra of cis‐ and trans‐fused 1,2,3,4,4a,5,6,7,8,8a‐decahydro‐1,3,2‐benzodiazaphosphinine 2‐oxides (1–17) were recorded, and the fragmentation pathways were established and compared with those of 1,4,4a,5,6,7,8,8a‐octahydro‐2H‐3,1,2‐benzoxazaphosphinine 2‐oxides. In general, the mass spectral behaviors of the isomeric compounds were very similar and it was mostly impossible to differentiate them from each other on the basis of the relative abundances of their characteristic fragment ions. The compounds in which R2 = Ph or OPh exhibited a series of common fragments, e.g. [R2H]+, R2PONHR1(3)+, [M–C3H7]+ and [M–C4H9]+, the latter two ions being present in the spectra of only two of the derivatives with an N(CH2CH2Cl)2 substituent on the P atom. When R2 = Ph, numerous other alkyl radicals, alkenes and a cycloalkane were also ejected and these compounds also lost NH2, NH3, CH3N, CH4N or CH3NH2. The compounds with an N(CH2CH2Cl)2 substituent on the P atom most closely resembled their 3,1,2‐O,N,P analogs in respect of the dominant role of this substituent. Copyright © 2006 John Wiley & Sons, Ltd.
Dissociation of biomolecules using a ultraviolet matrix‐assisted laser desorption/ionisation time‐of‐flight/curved field reflectron tandem mass spectrometer equipped with a differential‐pumped collision cell
Authors: Belgacem Omar , Bowdler Andrew , Brookhouse Ian , Brancia Francesco L , Raptakis Emmanuel
Published: April 2006

A commercial matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐ToF) instrument equipped with a curved field reflectron (CFR) was modified in order to perform collision‐induced dissociation (CID) on a variety of biomolecules. The incorporation of a high‐resolution ion gate together with a collision cell within the field‐free region allowed tandem mass analysis (MS/MS), without the necessity to decelerate the precursor ions prior to activation. The simultaneous detection of all product ions remained possible by using the CFR. To test the MS/MS performances, ACTH (fragment 1–17), a complex high mannose carbohydrate (Man)8(GlcNac)2 and a lysophosphatidylcholine lipid (18:1) were analysed on the modified instrument. Direct comparison with the low‐energy product ion spectra, acquired on a MALDI quadrupole ion trap (QIT) two‐stage reflectron time‐of flight (ReToF) mass spectrometer, showed significant differences in the types of product ions observed. The additional ions detected were a clear indication of the high‐energy fragmentation processes occurring in the collision cell. Copyright © 2006 John Wiley & Sons, Ltd.
Superintegrable quantum u(3) systems and higher rank factorizations
Authors: Calzada J. A. , Negro J. , del Olmo M. A.
Published: April 2006

A class of two-dimensional superintegrable systems on a constant curvature surface is considered as the natural generalization of some well known one-dimensional factorized systems. By using standard methods to find the shape-invariant intertwining operators we arrive at a so(6) dynamical algebra and its Hamiltonian hierarchies. We pay attention to those associated to certain unitary irreducible representations that can be displayed by means of three-dimensional polyhedral lattices. We also discuss the role of superpotentials in this new context.
Extraordinary eddy-current anomaly in nanocrystalline FeCuNbSiB wires under circular ac magnetization
Authors: Chen D.-X.
Published: April 2006

The circular ac susceptibility of nanocrystalline FeCuNbSiB wire devitrified from its amorphous precursor by tension-current annealing is determined from ac impedance measurements. The results are shown to be well fitted by an eddy-current model of bamboo-domain wall displacements, but the frequency scale of the modeling curves has to be divided by a number ⪢1. In contrast to the well-known eddy-current anomaly resulting from the existence of large domains, this eddy-current anomaly is extraordinary and originates from the presence of dispersed micromagnetic reversal regions within each domain, which exposes a remarkable feature of the magnetic structure of nanocrystalline materials.
Direct nitric oxide measurement in human spermatozoa: flow cytometric analysis using the fluorescent probe, diaminofluorescein
Authors: Lampiao Fanuel , Strijdom Hans , Du Plessis Stefan S.
Published: April 2006

We have demonstrated that intracellular nitric oxide (NO) can be detected and measured directly in human spermatozoa by flow cytometry using the fluorescent probe 4,5‐diaminofluorescein‐2/diacetate (10 μm). This method can measure both exogenously added as well as endogenously generated intracellular NO.
Maternal MTR genotype contributes to the risk of non‐syndromic cleft lip and palate in the Polish population
Authors: Mostowska A , Hozyasz KK , Jagodzinski PP
Published: April 2006

The aetiology of non‐syndromic cleft lip with or without cleft palate (CL/P) is very complex. It has been shown that polymorphic variants of genes encoding key proteins of folate and methionine metabolism might be important maternal risk factors of having a child with this craniofacial anomaly. Therefore, in our study, mothers with CL/P children as well as control mothers were examined for prevalence of polymorphisms of genes that encode methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR), 5,10‐methylenetetrahydrofolate dehydrogenase, 5,10‐methenyltetrahydrofolate cyclohydrolase and 10‐formyltetrahydrofolate synthetase (MTHFD1) and reduced folate carrier 1 (RFC1). We observed that there were no statistical differences in allele and genotype frequencies of MTHFR c.677C>T, MTHFD1 c.1958G>A and RFC1 c.80G>A between mothers who had children with CL/P and control mothers. However, mothers with MTR c.2756AG or GG genotype displayed a 2.195‐fold increased risk of having a child with CL/P (95% CI 1.189–4.050, p = 0.011). The mechanism by which polymorphic transition of MTR gene might increase the maternal risk of having CL/P progeny is unknown. Our observations are consistent with a significant role of the methyl cycle in the development of craniofacial structures in humans.
ASSET PRICE BUBBLES, LIQUIDITY PREFERENCE AND THE BUSINESS CYCLE
Authors: Erturk Korkut A.
Published: April 2006

In his Treatise on Money, Keynes relied on two different themes to argue that the interest rate need not rise with rising levels of expenditure. One of these was the elasticity of the money supply, and the other was the interaction between financial and industrial circulation. A decrease (increase) in what Keynes called the bear position was similar in its impact to that of a policy‐induced increase (decrease) in the money supply. In the General Theory, this second line of argument lost much of its force as it became reformulated under the rubric of Keynes liquidity preference theory of interest. Assuming that the expected return on capital adjusts to the interest rate in short‐period equilibrium, Keynes ignored the effect of bull or bear sentiment in equity markets as a second‐order complication that can be ignored in analyzing the equilibrium level of investment and output. The objective of this paper is to go back to this old theme from the Treatise and underscore its importance for Keynesian theory of the business cycle.
COMPARATIVE DYNAMICS AND OPTIMAL FISCAL POLICY IN A SIMPLE MODEL OF ENDOGENOUS GROWTH
Authors: Weber Christian E.
Published: April 2006

I analyze optimal fiscal policy choices in a continuous time endogenous growth model similar to Barro’s. The government uses income taxes from representative ‘rich’ and ‘poor’ households to finance purchases of productive goods and to make transfer payments to poor households. Increases in government purchases can increase the growth rate, while increases in transfers reduce growth. I examine the socially optimal allocation of government resources to purchases and transfer payments and describe conditions under which both the rich and poor would benefit from cuts in entitlements if the savings are used to finance increased government purchases of productive goods.
Short communication: Laser Doppler perfusion imaging: a method for measuring female sexual response
Authors: Styles SJ , MacLean AB , Reid WMN , Sultana SR
Published: April 2006

To develop a new noninvasive technique to measure vulval blood flow changes during sexual arousal; 18 healthy volunteers between the age of 20 and 33 years were studied. Each subject underwent two experimental sessions at least 2 weeks apart to coincide with the proliferative and luteal phases of her menstrual cycle. An initial laser Doppler perfusion imaging (LDPI) scan of the vulva was performed. The subject was then given a chapter of erotic fiction to read and a repeat LDPI scan was performed immediately after. The percentage change in flux were calculated: the clitoral skin blood flow increased by 26.4% (P < 0.05), labial skin blood flow by 24.9% (P < 0.05) and the posterior fourchette skin blood flow by 35.3% (P < 0.05). LDPI can detect changes in vulval perfusion during the sexual arousal response and could be used to compare healthy subjects with female sexual dysfunction patients, as well as for assessing the benefits of any treatment for this condition.
CLASSIFICATION OF OCCUPATIONAL INJURY CASES USING THE REGRESSION TREE APPROACH
Authors: PERSONA ALESSANDRO , BATTINI DARIA , FACCIO MAURIZIO , BEVILACQUA MAURIZIO , CIARAPICA FILIPPO EMANUELE
Published: April 2006

Occupational safety and illness surveillance has made a great effort to spread a "safety culture" to all workplaces and a great deal of progress has been made in finding solutions that guarantee safer working conditions.This paper analyses occupational injury data in order to identify specific risk groups and factors that in turn could be further analyzed to define prevention measures.

A technique based on rule induction is put forward as a non-parametric alternative tool for analyzing occupational injury data which specifically uses the Classification And Regression Tree (CART) approach. Application of this technique to relevant work-related injury data collected in Italy has been encouraging. Data referring to 156 cases of injury in the period 2000–2002 were analyzed and lead to the factors that most affect work-related injuries being identified.

According to the literature, up to the time of writing computer-intensive non-parametric modeling procedures have never been used to analyze occupational injuries. The aim of this paper is to use a real world application to illustrate the advantages and flexibility of applying a typical non-parametric epidemiological tool, such as CART, to an occupational injury study.

This application can provide more informative, flexible, and attractive models identifying potential risk areas in support of decision-making in safety management.
Communication Skills in Psychiatry Residents – How Do They Handle Patient Concerns?
Authors: Rimondini Michela , Del Piccolo Lidia , Goss Claudia , Mazzi Mariangela , Paccaloni Monica , Zimmermann Christa
Published: April 2006

Background: The main focus of the training of psychiatrists is on diagnosis and treatment based on the traditional doctor-centered approach to the psychiatric interview. Less attention is given to the correct handling of patients’ emotional concerns, which is crucial for the patient-physician relationship, but also for improving diagnostic and treatment decisions. The aim of this study is to assess psychiatrists’ responses to patients’ concerns and worries. Method: 118 consultations, conducted by 10 residents in psychiatry with 20 simulated patients, have been coded using the Verona Psychiatric Interview Classification System. Lag1 sequential analysis and a multinomial logit regression analysis were performed to investigate the relationship between patients’ expressions of concern and psychiatrists’ subsequent interventions in terms of patient-centered skills. Results: Compared to doctor-centered interventions, all patients’ expressions of concern increased the probability of passive listening (odds ratios between 2.4 and 4.2). They also increased the occurrence of emotion focusing interventions (odds ratios between 3.3 and 1.7), which however remained rare (4% of residents’ total responses). A small although significant increase in the likelihood of active listening expressions was observed as a response to two types of patient expressions of concern: statements of feelings (odds ratio 1.4) and expression of opinions regarding problematic psychosocial issues (odds ratio of 1.7). Conclusions: Young psychiatrists are good passive listeners but need to improve active listening skills which, together with emotion focusing skills, should be a major learning target in psychiatry. These patient-centered interviewing skills should integrate those traditionally used for attributing ICD-10 and/or DSM-IV categories.
Evaluation of Exercise Capacity with Cardiopulmonary Exercise Testing and Type B Natriuretic Peptide Concentrations in Adult Patients with Patent Atrial Septal Defect
Authors: Trojnarska Olga , Szyszka Andrzej , Gwizdala Adrian , Oko-Sarnowska Zofia , Katarzynski Slawomir , Siniawski Andrzej , Chmara Ewa , Cieslinski Andrzej
Published: April 2006

Adults with patent atrial septal defect (ASD) usually find their exercise capacity satisfactory, and therefore hesitate to accept proposed surgical treatment of the heart disease. The aim of our study was to evaluate both the exercise capacity, using the cardio-pulmonary stress test, and brain natriuretic peptide (BNP) levels in asymptomatic adults with ASD. Thirty-six patients with patent secundum type ASD (aged mean 44.7 ± 8.2 years) were studied. The control group consisted of 25 healthy subjects at the mean age of 45.6 ± 6.1 years. Echocardiography and CPST were performed and BNP levels measured in all subjects. Oxygen uptake (VO2 max) was lower in ASD patients than in controls (22.1 ± 5.6 vs. 30.0 ± 6.8 ml/kg/min, p = 0.00001); the VE/VO2 slope was elevated in ASD patients compared with healthy subjects (31.3 ± 6.6 vs. 26.9 ± 3.3, p = 0.001), and exceeded 34 in 5 patients. VO2 max showed a negative correlation with the pulmonary to systemic flow ratio Qp:Qs (r = –0.46, p = 0.004), and a positive correlation was found between the VE/VO2 slope and Qp:Qs (r = 0.32, p = 0.05). BNP levels were higher in the ASD group than in the controls (60.6 ± 49.9 vs. 32.6 ± 24.5 pg/ml, p = 0.02). BNP correlated positively with RV diameter and Qp:Qs (r = 0.38 and 0.39 respectively, p = 0.03) and negatively with maximum VO2 (r = –0.5, p = 0.004) and VO2% (r = –0.32, p = 0.07). Conclusions: Although most adult patients with ASD perceive their exercise capacity as satisfactory, objective assessment reveals that in fact it is significantly decreased. BNP levels are increased comparing to healthy individuals. Decreased exercise capacity and increased BNP levels seem to result from right ventricular volume overload.
Progression of Advanced Interatrial Block to Atrial Flutter: A Prospectively-Followed Case
Authors: Ariyarajah Vignendra , Spodick David H.
Published: April 2006

Interatrial block (IAB; P wave ≧110 ms), commonly associated with left atrial enlargement and its electromechanical dysfunction, is also a significant correlate of atrial tachyarrhythmias. While the arrhythmogenic mechanisms of atrial fibrillation and atrial flutter may indeed differ, there is actually considerably less literature showing evidence of prospective progression of IAB, be it partial or advanced, to atrial flutter. We present a unique case of atrial flutter occurring within months of diagnosis of advanced IAB in an otherwise healthy female to briefly generate our discussion on the possible reasons for this scenario.
Effects of Schisandrin B Enantiomers on Cellular Glutathione and Menadione Toxicity in AML12 Hepatocytes
Authors: Chiu Po Yee , Leung Hoi Yan , Poon Michel K.T. , Mak Duncan H.F. , Ko Kam Ming
Published: April 2006

Effects of schisandrin B enantiomer ((+)Sch B and (–)Sch B) treatment on the reduced cellular glutathione (GSH) level and susceptibility to menadione-induced toxicity were investigated and compared in AML12 hepatocytes. (+)Sch B or (–)Sch B treatment at 6.25 µmol/l produced a time-dependent change in cellular GSH level, with the maximal stimulation occurring 16 h after dosing. (+)Sch B/(–)Sch B pretreatment for 16 h dose-dependently protected against menadione toxicity, with the maximum degree of protection observable at 6.25 µmol/l and the extent of protection afforded by (–)Sch B being larger than that of (+)Sch B. The cytoprotection was associated with a parallel enhancement in cellular GSH level in both non-menadione (control) and menadione-intoxicated cells. While the GSH depletion produced by buthionine sulfoximine/phorone treatment largely abrogated the cytoprotective action of (+)Sch B/(–)Sch B, it almost completely abolished the GSH-enhancing effect of (+)Sch B and (–)Sch B in both control and menadione-treated cells. Both (+)Sch B and (–)Sch B treatments increased the GSH reductase activity in control and menadione-treated cells, with the stimulatory action of (–)Sch B being more potent than that of (+)Sch B in the control condition. (+)Sch B and (–)Sch B also enhanced the γ-glutamate cysteine ligase activity in menadione-intoxicated cells. The results indicate that (–)Sch B is more effective than (+)Sch B in enhancing cellular GSH and protecting against oxidant injury in hepatocytes.
Influence of Baicalin on the Expression of Receptor Activator of Nuclear Factor-κB Ligand in Cultured Human Periodontal Ligament Cells
Authors: Wang Guo-fang , Wu Zhi-fen , Wan Ling , Wang Qin-tao , Chen Fa-ming
Published: April 2006

Background: Baicalin is a flavonoid purified from the medicinal plant Scutellaria baicalensis Georgi. It has been reported that baicalin exhibits antibacterial, anti-inflammatory and analgesic effects and can inhibit nuclear factor-ĸB activation. Periodontal disease is a chronic infective disease of the periodontium caused by bacteria present in dental plaque inducing alveolar bone resorption until teeth are lost. Human periodontal ligament (HPDL) is the connective tissue between alveolar bone and tooth. Receptor activator of nuclear factor-ĸB ligand (RANKL), a member of the tumor necrosis factor (TNF) ligand family, plays an important role in osteoclastogenesis from osteoclast precursors to mature osteoclasts. In this study we investigate the effects of baicalin on RANKL protein production and messenger RNA (mRNA) expression induced by IL-1β in cultured HPDL cells. Methods: To induce RANKL expression, IL-1β was added to serum-free medium HPDL cells and incubated. Various concentrations of baicalin (0, 0.001, 0.01 and 0.1 µg/ml) were added to the medium and the cells were treated for 0, 12, 24, 48 and 72 h, respectively. RANKL in the cells was detected using immunocytochemistry. The mRNA of RANKL, osteoprotegerin (OPG) and cyclooxygenase-2 (COX-2) were measured by semiquantitative reverse transcription-polymerase chain reaction. Results: The expression of RANKL at mRNA and protein levels in HPDL cells was stimulated by IL-1β. Baicalin suppressed IL-1β-induced RANKL and COX-2 production at a concentration of 0.01 µg/ml. The most prominent effect was observed with 48 h of baicalin treatment. The inhibition of baicalin on the rhIL-1β-stimulated OPG expression was first apparent at 24 h after the start of treatment, however it did not reach significant differences. Conclusions: The data suggest that baicalin may inhibit RANKL mRNA expression via the suppression of COX-2 expression induced by IL-1β. In addition to its antibacterial and anti-inflammatory properties, baicalin was shown to be effective in periodontitis and alveolar bone resorption.
Activity of the Essential Oil from Chenopodium ambrosioides Grown in Cuba against Leishmania amazonensis
Authors: Monzote Lianet , Montalvo Ana M. , Almanonni Salah , Scull Ramón , Miranda Migdalia , Abreu Juan
Published: April 2006

Background and Methods: Current therapy against leishmaniasis is unsatisfactory. Efficacious and safe new drugs are needed.In this study, we show the leishmanicidal effect of an essential oil from Chenopodiumambrosioides against Leishmania amazonensis. Results: The tested product had a potent inhibitory action against promastigote and amastigote forms, with 50% effective dose values of 3.7 and 4.6 µg/ml, respectively. The essential oil showed a moderate toxicity on macrophages from BALB/c mice. An optimal dose of 30 mg/kg/day was effective when administered during 15 days by intraperitoneal route to BALB/c mice infected experimentally. Conclusion: These studies revealed a potential source for the discovery of novel drugs to combat the leishmaniasis based on the traditional medicine.
A pentecostal Response to Pinnock’s Proposal
Authors: Gause R.
Published: April 2006

This response to Clark Pinnock’s proposal for Pentecostal ecclesiology appreciates the affirming and promising directions that have been offered. Yet the respondent also recognizes the many significant ecclesiological contributions in the early practice, polity, and literature of the Pentecostal movement that have not been sufficiently acknowledged due to their being manifest in forms other than those of formal academic theology—a fact that should not be allowed to diminish recognition of their ecclesiological import and impact.
A pentecostal Appropriation of the Wesleyan Quadrilateral
Authors: Bevins Winfield
Published: April 2006

It is important for Pentecostals to re-examine the theological method of John Wesley, not merely to imitate what he has done, but to utilize his sources for developing a method that is contemporary, ecumenical, and Pentecostal. This study will utilize the so-called Wesleyan Quadrilateral as a model for further theological dialogue between Wesleyan and Pentecostal traditions by demonstrating that there is a unique pneumatology in Wesley’s theological method. This article will examine the historiography of the Wesleyan Quadrilateral, analyze the role of the Holy Spirit in each of the four areas (Scripture, reason, tradition, experience), and then offer a Pentecostal appropriation of the Wesleyan Quadrilateral.
Synthesis and Electrophosphorescent Properties of a Novel Iridium Complex with Arylamine Unit in the Polymer Light-emitting Devices
Authors: Wu Zhonglian , Xing Kongqiang , Luo Cuiping , Liu Yu , Yang Yuping , Gan Quan , Zhu Meixiang , Jiang Changyun , Cao Yong , Zhu Weiguo
Published: April 2006

A novel Ir complex, (BuPhNPPy)2Ir(acac) with arylamine unit, was synthesized. A peak external quantum efficiency of 10.4% photons per electron at current density of 32 mA/cm2 and a maximum luminance of 14610 cd/m2 at drive voltage of 24 V were achieved in a single-layered polymer light-emitting device using this Ir complex as dopant with 4% dopant concentration and a blend of poly(vinylcarbazole) as host matrix. The highly efficient electrophosphorescence of the Ir complex was exhibited with green emission at 533 nm.