bluuebunny/crossref_metadata_2025 huggingface dataset:
How to compare two systems
Authors: Ebrahimi Nader
Published: April 2006

Consider two systems with identical components but different structure functions. In this paper we propose a method to compare these two systems when the marginal behaviors of components are specified but when the complete joint behavior of components is unspecified. We also give two useful theorems for applying our method. We apply our techniques to two examples.
An elementary proof of Sengupta's invariance relation and a remark on Miyazawa's conservation principle
Authors: Brémaud P.
Published: April 2006

In this short note we derive Sengupta's (1989) invariance relation using elementary arguments and we show that Miyazawa's (1983), (1985) conservation principle, on which Sengupta's proof is based, admits the Palm inversion formula as a consequence. This contrasts with Miyazawa's first proof based on the inversion formula. We also show that Neveu's (1976) cycle formula is a direct consequence of Miyazawa's principle.
On Beurling's inequality in terms of thermal power
Authors: Kalpazidou S.
Published: April 2006

Beurling's inequality is proved to have an interpretation in terms of ingredients that do not depend on the effective numerical contribution of transition probabilities of circuit processes (those processes whose transition law is expressed by a denumerable class of directed weighted circuits). Connections with reversibility for Sk-state, k≧2, circuit processes, where S is a denumerable set, are revealed.
Orientation-dependent chord length distributions characterize convex polygons
Authors: Nagel W.
Published: April 2006

It is shown that the convex polygons are uniquely determined (up to translation and reflection) by their covariograms. The covariogram can be represented by the ‘orientation-dependent chord length distribution', i.e. the distribution of the length of chords which are generated by random lines parallel to fixed directions. Thus the result contributes to answer Blaschke's question about the content of information comprised in chord length distributions.
On the rate of convergence of some functionals of a stochastic process
Authors: Rachev S. , Todorovic P.
Published: April 2006

This paper is concerned with the rate of convergence of certain functionals associated with a stochastic process arising in the modelling of soil erosion. Some limit theorems are derived for the total crop production Sn over a number n of years, and the rate of convergence of Sn to its limit S is discussed. Some stability assumptions are considered, and particular stable geometric infinitely divisible processes analyzed.
A note on the total size distribution of carrier-borne epidemic models
Authors: Ball Frank
Published: April 2006

The coupling method of Ball (1986) is extended to carrier-borne epidemics, thus providing a new proof of a result of Daniels (1972) concerning the total size distribution of Downton's stochastic carrier-borne epidemic. The generalization to multipopulation carrier-borne epidemics is immediate.
On the virtual waiting time in an M/G/1 retrial queue
Authors: Falin G. , Fricker C.
Published: April 2006

This paper deals with the stationary distribution of the virtual waiting time, i.e. the time between the arrival and the beginning of service of a customer in a single-server queue that operates as follows. If the server is busy at an arrival time, the customer is rejected. This customer attempts service again after some random delay and continues to do so until the first time at which the server is idle. At this time, the customer is served and leaves the system after service completion. Interarrival times and delays are assumed to be two independent sequences of i.i.d. exponentially distributed random variables. Service times are also i.i.d., generally distributed, and independent of the previous sequences.
On the limiting distribution of a supercritical branching process in a random environment
Authors: Hambly Ben
Published: April 2006

We consider an increasing supercritical branching process in a random environment and obtain bounds on the Laplace transform and distribution function of the limiting random variable. There are two possibilities that can be distinguished depending on the nature of the component distributions of the environment. If the minimum family size of each is 1, the growth will be as a power depending on a parameter α. If the minimum family sizes of some are greater than 1, it will be exponential, depending on a parameter γ. We obtain bounds on the distribution function analogous to those found for the simple Galton-Watson case. It is not possible to obtain exact estimates and we are only able to obtain bounds to within ε of the parameters.
On distributions having the almost-lack-of-memory property
Authors: Chukova S. , Dimitrov B.
Published: April 2006

It is shown that random variables X exist, not exponentially or geometrically distributed, such that

P{X – b ≧ x | X ≧ b} = P{X ≧ x}

for all x > 0 and infinitely many different values of b. A class of distributions having the given property is exhibited. We call them ALM distributions, since they almost have the lack-of-memory property. For a given subclass of these distributions some phenomena relating to service by an unreliable server are discussed.
On the moments of ladder epochs for driftless random walks
Authors: Chow Yuan S.
Published: April 2006

Let X, X1, X2, … be i.i.d. Sn=Σ1nXj, E|X| > 0, E(X) = 0 and τ = inf {n ≥ 1: Sn ≥ 0}. By Wald's equation, E(τ) =∞. If E(X2) <∞, then by a theorem of Burkholder and Gundy (1970), E(τ1/2) =∞. In this paper, we prove that if E((X–)2) <∞, then E(τ1/2) =∞. When X is integer-valued and X ≥ −1 a.s., a necessary and sufficient condition for E(τ1–1/p) <∞, p > 1, is Σn–1–1p E|Sn| <∞.
The Beňes equations for the distribution of excursions for general storage processes
Authors: Guillemin Fabrice , Mazumdar Ravi
Published: April 2006

In this paper we obtain the Beňes equation for the evolution of the probability distribution of the excursion process associated with the level crossings of a general storage process. We then show that under stationarity and ergodicity assumptions on the process we can recover the well-known rate conservation law (RCL). Using the stationary solution we then show that the existence of an invariant solution can be studied in terms of an operator equation and we show how this characterization leads to a very simple explicit computation of the stationary distribution.
Simple random walk statistics. Part I: Discrete time results
Authors: Katzenbeisser W. , Panny W.
Published: April 2006

In a famous paper, Dwass (1967) proposed a method to deal with rank order statistics, which constitutes a unifying framework to derive various distributional results. In the present paper an alternative method is presented, which allows us to extend Dwass's results in several ways, namely arbitrary endpoints, horizontal steps and arbitrary probabilities for the three step types. Regarding these extensions the pertaining rank order statistics are extended as well to simple random walk statistics. This method has proved appropriate to generalize all results given by Dwass. Moreover, these discrete time results can be taken as a starting point to derive the corresponding results for randomized random walks by means of a limiting process.
The optimality of LEPT in parallel machine scheduling
Authors: Chang Cheng-Shang , Righter Rhonda
Published: April 2006

We consider preemptive scheduling on parallel machines where the number of available machines may be an arbitrary, possibly random, function of time. Processing times of jobs are from a family of DLR (decreasing likelihood ratio) distributions, and jobs may arrive at random agreeable times. We give a constructive coupling proof to show that LEPT stochastically minimizes the makespan, and that it minimizes the expected cost when the cost function satisfies certain agreeability conditions.
Shock models by underlying counting process
Authors: Pellerey Franco
Published: April 2006

Suppose that a device is subjected to shocks governed by a counting process N = {N(t), t ≧0}. The probability that the device survives beyond time t is then H̄(t)=Σk=0∞Q̄ℙ[N(t)=k], where Q̄k is the probability of surviving k shocks. It is known that H is NBU if the interarrivals Uk, ∊ ℕ+, are independent and NBU, and Q̄k+j ≦ Q̄k· Q̄j holds whenever k, j ∊ ℕ. Similar results hold for the classes of the NBUE and HNBUE distributions. We show that some other ageing classes have similar properties.
Applications of the hazard rate ordering in reliability and order statistics
Authors: Boland Philip J. , El-Neweihi Emad , Proschan Frank
Published: April 2006

The hazard rate ordering is an ordering for random variables which compares lifetimes with respect to their hazard rate functions. It is stronger than the usual stochastic order for random variables, yet is weaker than the likelihood ratio ordering. The hazard rate ordering is particularly useful in reliability theory and survival analysis, owing to the importance of the hazard rate function in these areas. In this paper earlier work on the hazard rate ordering is reviewed, and extensive new results related to coherent systems are derived. Initially we fix the form of a coherent structure and investigate the effect on the hazard rate function of the system when we switch the lifetimes of its components from the vector (T1, · ··, Tn) to the vector (T′1, · ··, T′n), where the hazard rate functions of the two vectors are assumed to be comparable in some sense. Although the hazard rate ordering is closed under the formation of series systems, we see that this is not the case for parallel systems even when the system is a two-component parallel system with exponentially distributed lifetimes. A positive result shows that for two-component parallel systems with proportional hazards (λ1r(t), λ2r(t))), the more diverse (λ1, λ2) is in the sense of majorization the stronger is the system in the hazard rate ordering. Unfortunately even this result does not extend to parallel systems with more than two components, demonstrating again the delicate nature of the hazard rate ordering.

The principal result of the paper concerns the hazard rate ordering for the lifetime of a k-out-of-n system. It is shown that if τ k|n is the lifetime of a k-out-of-n system, then τ k|n is greater than τ k+1|n in the hazard rate ordering for any k. This has an interesting interpretation in the language of order statistics. For independent (not necessarily identically distributed) lifetimes T1, · ··, Tn, we let Tk:n represent the kth order statistic (in increasing order). Then it is shown that Tk +1:n is greater than Tk:n in the hazard rate ordering for all k = 1, ···, n − 1. The result does not, however, extend to the stronger likelihood ratio order.
The critical contact process on a homogeneous tree
Authors: Morrow Gregory J. , Schinazi Rinaldo B. , Zhang Yu
Published: April 2006

We prove that the expected number of particles of the critical contact process on a homogeneous tree is bounded above. This is the first graph for which the behavior of the expected number of particles of the critical contact process is known. As an easy corollary of our result we get that the critical contact process dies out on any homogeneous tree. This completes the work of Pemantle (1992).
A non-exponential generalization of an inequality arising in queueing and insurance risk
Authors: Willmot Gordon E.
Published: April 2006

An exponential inequality is generalized to one involving the tail of a decreasing failure rate distribution. The results are then applied in various situations, notably when the exponential inequality does not apply.
Computing the invariant law of a fluid model
Authors: Rogers L. C. G. , Shi Z.
Published: April 2006

In this paper, we discuss a variety of methods for computing the Wiener-Hopf factorization of a finite Markov chain associated to a fluctuating additive functional. The importance of this is that the equilibrium law of a fluid model can be expressed in terms of these Wiener–Hopf factors. The diagonalization methods considered are actually quite efficient, and provide an effective solution to the problem.
On identifiability and order of continuous-time aggregated Markov chains, Markov-modulated Poisson processes, and phase-type distributions
Authors: Rydén Tobias
Published: April 2006

An aggregated Markov chain is a Markov chain for which some states cannot be distinguished from each other by the observer. In this paper we consider the identifiability problem for such processes in continuous time, i.e. the problem of determining whether two parameters induce identical laws for the observable process or not. We also study the order of a continuous-time aggregated Markov chain, which is the minimum number of states needed to represent it. In particular, we give a lower bound on the order. As a by-product, we obtain results of this kind also for Markov-modulated Poisson processes, i.e. doubly stochastic Poisson processes whose intensities are directed by continuous-time Markov chains, and phase-type distributions, which are hitting times in finite-state Markov chains.
Poly(3,4‐alkylenedioxypyrroles): The PXDOPs as Versatile Yet Underutilized Electroactive and Conducting Polymers
Authors: Walczak R. M. , Reynolds J. R.
Published: April 2006

The poly(3,4‐dioxypyrrole) (PXDOP) family of conducting and electroactive polymers has now been developed to the point that multiple synthetic routes allow many functionalized polymers with controllable optoelectronic and redox properties. These properties, which include high conductivity, multicolor cathodic and anodic electrochromism, and rapid redox switching, allow these materials to be used in a variety of applications that potentially include conducting coatings, electrochromic windows and displays, chemical sensors, bioactive materials, and mechanical actuators. Surprisingly, the scientific literature published on the PXDOP derivatives has been isolated and sparse compared to that of other conducting polymers. This report will highlight the synthesis and materials properties of PXDOPs and show how these powerful materials fit into the frontier of conducting polymers research.
Enantiomeric separation of mineralocorticoid receptor (hMR) antagonists using the Chiralcel® OJ‐H HPLC column with novel polar cosolvent eluent systems
Authors: Sharp V. Scott , Kennedy Joseph H. , Belvo Matthew D. , Williams Jeffrey D. , Risley Donald S. , Seest Eric P.
Published: April 2006

This study demonstrates the increased versatility of the Chiralcel® OJ‐H stationary phase when using various alcohol/acetonitrile mobile phases. This chiral stationary phase has traditionally been employed in the normal phase mode and more recently with neat alcohols as eluents. Selected isomeric human mineralocorticoid receptor (hMR) antagonist pharmaceutical candidates and synthetic intermediates were separated using the Chiralcel® OJ‐H HPLC column with novel polar cosolvent eluent systems. The capacity factors, resolution, and selectivity of the chiral separations were assessed while varying the alcohol/acetonitrile composition and alcohol identity. The mixed polar eluents provide separations that are nearly always superior to both the traditional hexane‐rich and single‐alcohol “polar organic” eluents for the compounds tested in this article. Chirality, 2006. © 2006 Wiley‐Liss, Inc.
Exenatide elicits sustained glycaemic control and progressive reduction of body weight in patients with type 2 diabetes inadequately controlled by sulphonylureas with or without metformin
Authors: Riddle Matthew C. , Henry Robert R. , Poon Terri H. , Zhang Bei , Mac Susanna M. , Holcombe John H. , Kim Dennis D. , Maggs David G.
Published: April 2006

Background

In two placebo‐controlled 30‐week trials, treatment with exenatide reduced HbA1c and body weight in patients with type 2 diabetes in the context of sulphonylurea (SU) or SU plus metformin (MET) as background treatment. This analysis examines the effects of 82 weeks of exenatide treatment for participants in these earlier 30‐week trials.

Methods

Data were pooled from the two pivotal trials of exenatide added to SU or SU plus MET. Both 30‐week, placebo‐controlled trials of 5 µg or 10 µg exenatide b.i.d. were followed by 52‐week open‐label, uncontrolled extension studies in which all participants received 10 µg exenatide b.i.d. and continued prior oral therapies. This interim analysis includes data for 222 patients who completed 82 weeks of exenatide treatment (61% M, age 57 ± 10 y, weight 99 ± 21 kg, BMI 34 ± 6 kg/m2, HbA1c8.4 ± 1.0% [mean ± SD]).

Results

Reduction in HbA1c from baseline to week 30 (−0.8 ± 0.1% and −1.0 ± 0.1% for 5 µg b.i.d. and 10 µg b.i.d., respectively [mean ± SE]) was sustained up to week 82 (−1.0 ± 0.1%). Of 207 patients with baseline HbA1c > 7%, 44% achieved HbA1c ≤ 7% at week 82. Reduction of body weight from baseline to week 30 (−1.4 ± 0.3 kg and −2.1 ± 0.3 kg for 5 µg b.i.d. and 10 µg b.i.d., respectively) was progressive up to week 82 (−4.0 ± 0.3 kg). The most frequent adverse events were nausea and hypoglycaemia, both generally mild to moderate in intensity.

Conclusions

Exenatide added to maximally effective doses of SU or SU plus MET resulted in a sustained reduction in HbA1c and a progressive reduction in weight over $\def\qdr#1#2{\begingroup\hbox{\raise0.3em\hbox{$\scriptstyle #1$}$\!{/}\!$\lower0.2em\hbox{$\scriptstyle #2$}}\endgroup}1\qdr{1}{2}$ years. Copyright © 2006 John Wiley & Sons, Ltd.
Determination of tobacco‐specific N‐nitrosamines in rabbit serum by capillary zone electrophoresis and capillary electrophoresis‐electrospray ionization‐mass spectrometry with solid‐phase extraction
Authors: Li Chenchen , Chen Zheng , Wen Dawei , Zhang Jianxun , Cong Weihong , Yu Bing , Liao Yiping , Liu Huwei
Published: April 2006

In this paper, we propose a new strategy for separation and determination of tobacco‐specific N‐nitrosamines (TSNAs), a group of strong carcinogens found only in tobacco products, by using CZE and CE‐MS associated with SPE. Six TSNAs: N'‐nitrosonornicotine, N'‐nitrosoanatabine, N'‐nitrosoanabasine, 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone, 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol, and 4‐(methylnitrosamino)‐4‐(3‐pyridyl)‐1‐butanol were simultaneously separated by either of two CZE methods, one of which worked with ammonium formate buffer (pH 2.5) and another with citrate buffer (pH 2.4), as well as a CE‐MS method. The CZE conditions including pH and concentration of running buffer, capillary length, applied voltage, and capillary temperature were systematically optimized. For CE‐MS method, an optimized sheath liquid consisted of methanol–water was used at a flow rate of 10 μL/min. With SPE procedure, our proposed CE‐MS method was successfully applied to determine TSNAs after 15 min metabolism in rabbits. A comparison study between CZE and CE‐MS methods for quantitative purposes was carried out, showing that both methods provided similar separation efficiency, selectivity, repeatability, linearity, and recovery. However, CE‐MS method was better suited for the analysis of TSNAs in complicated biological samples for its sensitivity and extra information on molecular structure. Having good accordance with our previous work by using LC‐MS, the new CE‐MS method is expected to be an alternative to the LC‐MS method and applied to study the metabolism of TSNAs.
Phased retirement policies
Authors: Janson Natasha
Published: April 2006

Phased retirement policies are more or less attractive financially and more or less accommodating of individual differences. They are also implemented in varying ways, variations that especially affect departments and academic programs.
Assessing the geochemical reactivity of inorganic phosphorus along estuaries by means of laboratory simulation experiments
Authors: García‐Luque Enrique , Forja Pajares Jesús M. , Gómez‐Parra Abelardo
Published: April 2006

Phosphate behaviour in natural estuarine systems can be studied by performing field measurements and by undertaking laboratory simulation experiments. Thus, in this paper we describe the use of a dynamic automated estuarine simulator to characterize the geochemical reactivity of phosphate in varying salinity gradients in order to study possible mechanisms of phosphate removal from the dissolved phase (e.g. formation of some kind of apatite) and how changes in pH and salinity values influence this removal. Six laboratory assays, representing various salinity and pH gradients (average pH values between 7 and 8), were carried out. The geochemical equilibrium model MINTEQA2 was employed to characterize removal of phosphate. Among the minerals from which dissolved phosphate can originate, it seems that hydroxyapatite is by far the mineral that shows the greatest saturation indexes in the experiments. Thus, there is evidence that a type of calcium phosphate (hydroxyapatite) is involved in phosphate removal in the assays. Phosphate removal by Ca2+ occurs sharply at salinity values of 1–2, whereas by Fe3+ it is relatively gradual, at least until a salinity value of 7. Copyright © 2006 John Wiley & Sons, Ltd.
Comparison of impacts of dams on the annual maximum flow characteristics in three regulated hydrologic regimes in Québec (Canada)
Authors: Assani Ali A. , Stichelbout Émilie , Roy André G. , Petit François
Published: April 2006

Despite the presence of numerous dams in Québec, no study has yet been devoted to their impacts on flood levels. To compensate for this deficiency, we have compared the impacts of dams on the five characteristics (magnitude and its interannual variability, timing and its interannual variability, and asymmetry) of the maximum annual flows between natural rivers and regulated rivers by means of several statistical approaches (analysis of variance, chi‐square test, nonparametric tests, etc.). In the course of this study, we analysed 88 stations on pristine rivers and 60 stations on regulated rivers. The latter group was subdivided into three regulated hydrologic regimes, i.e. inversed flow regimes (25 stations), homogenization flow regimes (15 stations) and natural‐type flow regimes (20 stations). The following observations emerge from this study. (1) In inversed and homogenization flow regimes, generally associated with reservoirs, all the flow characteristics are modified. These modifications notably entrain a decrease in magnitude, a significant reduction in the frequency of the maximum annual spring flows when the snow is melting and an increase in skewness of the distribution and interannual variability of the magnitude and dates of occurrence of the annual maximum flows. We also observed the disappearance of most flows with a recurrence of over 10 years. All these changes particularly affect watersheds larger than 10 000 km2. (2) In natural‐type flow regimes, often associated with run‐of‐river dams, very few changes were observed compared with pristine rivers. These changes primarily affected watersheds smaller than 1000 km2. Copyright © 2006 John Wiley & Sons, Ltd.
Possible role of duration of PKC‐induced ERK activation in the effects of agonists and phorbol esters on DNA synthesis in panc‐1 cells
Authors: Rácz Gábor Z. , Szűcs Ákos , Szlávik Vanda , Vág János , Burghardt Beáta , Elliott Austin C. , Varga Gábor
Published: April 2006

Protein kinase C (PKC) and extracellular signal‐regulated kinase (ERK) have been implicated in the effects of regulatory peptides on proliferation. We studied how ERK was activated by PKC following regulatory peptide or phorbol ester stimulation and we also investigated the effect of ERK activation on proliferation in Panc‐1 cells. Panc‐1 cells transfected with CCK1 receptors were treated with cholecystokinin (CCK), neurotensin (NT), or phorbol 12‐myristate 13‐acetate (PMA). DNA synthesis was studied by measuring tritiated thymidine incorporation. PKC isoforms were selectively inhibited with Gö6983 and 200 nM Ro‐32‐0432, their translocation was detected by confocal microscopy and by subcellular fractionation followed by immunoblotting. ERK cascade activation was detected with phosphoERK immunoblotting and inhibited with 20 µM PD98059. PMA and CCK inhibited, NT stimulated DNA synthesis. These effects were inhibited by Ro‐32‐0432 but not by Gö6983 suggesting the involvement of PKCε in proliferation control. Confocal microscopy and subcellular fractionation demonstrated that PMA, CCK, and NT caused cytosol to membrane translocation of PKCε and ERK activation that was inhibited by Ro‐32‐0432 but not by Gö6983. ERK activation was prolonged following PMA and CCK, but transient after NT treatment. PMA, CCK, and NT all activated cyclinD1, while p21CIP1 expression was increased by only PMA and CCK, but not by NT; each of these effects is inhibited by PD98059. In conclusion, our results provide evidence for PKCε‐mediated differential ERK activation and growth regulation in Panc‐1C cells. Identification of the mechanisms by which these key signaling pathways are modulated could provide a basis for the development of novel therapeutic interventions to treat pancreatic cancer. J. Cell. Biochem. © 2006 Wiley‐Liss, Inc.
Enrichment of NRBC in maternal blood: a more feasible method for noninvasive prenatal diagnosis
Authors: Purwosunu Yuditiya , Sekizawa Akihiko , Farina Antonio , Okai Takashi , Takabayashi Haruo , Wen Peng , Yura Hirofumi , Kitagawa Michihiro
Published: April 2006

Objective

To assess the efficiency and reliability of the separation of fetal nucleated red blood cells (NRBCs) using the galactose‐specific lectin method, we counted the number of NRBCs in the blood of pregnant women at various gestational ages, as well as after amniocentesis and termination.

Method

Peripheral blood samples were obtained from (1) 22 singleton pregnant women (between 9 and 34 weeks of gestation) and from 23 women who underwent termination (between 6 and 19 weeks of gestation). To determine whether amniocentesis influences numbers of NRBCs, five samples were obtained (2) before and after the procedure. NRBC enrichment was initially performed using density gradients and subsequently using galactose‐specific lectin. The cells were then stained with May‐Gruenwald Giemsa (MGG) and counted under a light microscope.

Results

NRBCs were found in all samples, ranging from 1 to 82 (median = 12.5 cells/sample). The multiples of the median (MoM) conversion of the number of cells revealed a raise of 1.66‐fold (0.12–6.64) in post‐termination samples compared with the control value of 1.00 MoM (0.11–6.92; p = 0.036). The postamniocentesis increase was, instead, 1.11‐fold (0.17–4.02), which did not reach statistical significance.

Conclusion

All blood samples tested contained NRBCs. Samples obtained after termination yielded more cells than those obtained from women whose pregnancies were going on normally. The number of NRBCs in post‐termination samples after MoM conversion differed significantly from those in controls. Although separation of NRBCs was not feasible due to extremely low numbers, our results indicated that NRBCs are detectable in all blood samples from normal pregnant women. Copyright © 2006 John Wiley & Sons, Ltd.
On the in‐situ polymerization of cyclic butylene terephthalate oligomers: DSC and rheological studies
Authors: Ishak Z.A. Mohd , Gatos K.G. , Karger‐Kocsis J.
Published: April 2006

The thermal and rheological behaviors of cyclic butylene terephthalate (CBT) were studied with differential scanning calorimetry (DSC) and plate–plate rheometry, respectively. DSC scans were taken at different heating rates. The related first‐heat thermograms indicated crystallization and melting of the resulting poly (butylene terephthalate) (PBT) only at very low heating rate (0.5°C/min). As the crystallization and melting enthalpies were closely matched, one could conclude that the polymerization is essentially athermic. The polymerization was accompanied by a steep increase of the melt viscosity in isothermal rheological tests performed in the temperature range T = 145–210°C. Changes in the viscoelasticity of the polymerizing CBT and crystallizing PBT could be best followed by considering the changes in the phase angle. Viscosity increased with the conversion exponentially in the first approximation. POLYM. ENG. SCI., 46:743–750, 2006. © 2006 Society of Plastics Engineers
Proteome analysis of rice uppermost internodes at the milky stage
Authors: Yang Pingfang , Liang Yu , Shen Shihua , Kuang Tingyun
Published: April 2006

Uppermost internodes, which connect the part between the ear and lower stem, form an important pathway transporting mineral nutrition from roots and photosynthates from leaves (especially the flag leaf) to the ear. The milky stage is the first stage of seed ripening. The uppermost internodes of rice at the milky stage are critical for seed quality and yield. Total soluble proteins of the uppermost internodes of rice (Oryza sativa L. ssp. indica) at the milky stage were analyzed using proteomic methods. Using 2‐DE, 762 reproducible protein spots were detected. Among them, 132 abundant proteins were analyzed using MALDI‐TOF‐MS. Searching in the National Center for Biotechnology Information database, we could identify 98 proteins, which represent 80 gene products. These proteins belong to 11 functional groups with energy production‐associated proteins in the first place. The large accumulation of proteins involved in metabolism, signaling, and stress resistance indicated that the uppermost internodes of rice have a high physiological and stress‐resistant activity. In addition, our results will also enrich the database of the rice proteome.
Synthesis and application as polymer electrolyte of hyperbranched polyether made by cationic ring‐opening polymerization of 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxymethyl}‐3′‐methyl‐oxetane
Authors: Lin Ye , Zeng‐Guo Feng , Yu‐Mei Zhao , Feng Wu , Shi Chen , Guo‐Qing Wang
Published: April 2006

A novel cyclic ether monomer 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxy‐methyl}‐3′‐methyloxetane (HEMO) was prepared from the reaction of 3‐hydroxymethyl‐3′‐methyloxetane tosylate with triethylene glycol. The corresponding hyperbranched polyether (PHEMO) was synthesized using BF3·Et2O as initiator through cationic ring‐opening polymerization. The evidence from 1H and 13C NMR analyses revealed that the hyperbranched structure is constructed by the competition between two chain propagation mechanisms, i.e. active chain end and activated monomer mechanism. The terminal structure of PHEMO with a cyclic fragment was definitely detected by MALDI‐TOF measurement. A DSC test implied that the resulting polyether has excellent segment motion performance potentially beneficial for the ion transport of polymer electrolytes. Moreover, a TGA assay showed that this hyperbranched polymer possesses high thermostability as compared to its liquid counterpart. The ion conductivity was measured to reach 5.6 × 10−5 S/cm at room temperature and 6.3 × 10−4 S/cm at 80 °C after doped with LiTFSI at a ratio of Li:O = 0.05, presenting the promise to meet the practical requirement of lithium ion batteries for polymer electrolytes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3650–3665, 2006
Electrospinning of neat and laponite‐filled aqueous poly(ethylene oxide) solutions
Authors: Daga Vikram K. , Helgeson Matthew E. , Wagner Norman J.
Published: April 2006

Electrospinning is reported for viscoelastic aqueous solutions of poly(ethylene oxide) (PEO) and with added nanoclay (laponite). A weak correlation between fiber diameter and the spinning solution's zero‐shear viscosity is observed and compared with previous work reported by McKee et al. (McKee et al., Macromolecules 2004, 37, 1760). A new analysis of electrospinning results for PEO indicates a universal correlation between fiber diameter and solution properties that does not include shear viscosity as a primary variable. The addition of laponite nanoclay to the PEO solutions, which has been previously shown to result in rheologically simple solutions, leads to different fiber morphologies for the same shear viscosity in contradiction with reports for titania particles (Drew et al., J Macromol Sci Part A: Pure Appl Chem 2003, 40, 1415). The research identifies additional physicochemical properties that are important in determining electrospun fiber morphology. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1608–1617, 2006
The impact of diagnosis and plaque radiotherapy treatment of malignant choroidal melanoma on patients' quality of life
Authors: Reimer Jens , Voigtlaender‐Fleiss Anja , Karow Anne , Bornfeld Norbert , Esser Joachim , Helga Franke Gabriele
Published: April 2006

Quality of life (QOL) has become an important outcome criterion of medical interventions, but the impact of diagnosis and radiotherapy on QOL in patients with malignant choroidal melanoma (MCM) has rarely been studied. Inventories covering global (SF‐36) and disease‐specific QOL (NEI‐VFQ), mental distress (SCL‐90‐R), and social support (K‐22, German) were applied to a consecutive sample of MCM‐patients scheduled for plaque radiotherapy. Data were gathered preoperatively (t0) and 3 months postoperatively (t1, except for the K‐22, which was applied at t0 only). Fifty‐four patients took part in both surveys, the number of patients with visual impairment increased from 21 preoperatively to 34 postoperatively. Global QOL of MCM‐patients was significantly reduced compared to the healthy norm and other ophthalmological patients both at t0 and t1. Clinically relevant distress was present in every second patient at t0 and every third patient at t1, social support was not impaired. Global and disease‐specific QOL declined significantly from t1 to t0. The MCM diagnosis compromises QOL, which is additionally impaired by radiotherapy. Regular QOL assessment can help to identify patients at risk, facilitate provision of psychosocial treatment and may thus improve patient satisfaction. Copyright © 2006 John Wiley & Sons, Ltd.
Multi‐determinant trial functions in the determination of the dissociation energy of the beryllium dimer: Quantum Monte Carlo study
Authors: Harkless J. A. W. , Irikura K. K.
Published: April 2006

Both variational Monte Carlo (VMC) and fixed‐node diffusion Monte Carlo (DMC) are used to estimate the dissociation energy of Be2. The effect of using single‐ and multi‐reference trial functions on the quality of the Monte Carlo estimates is investigated, with independent‐particle wave functions ranging from a restricted Hartree–Fock (RHF) calculation up to a complete active space self‐consistent field (CASSCF) with four valence electrons in 12 active orbitals. It was determined that the best trial function for DMC had a high cutoff for inclusion and included all 2s and 2p orbitals in a CASSCF(4,8) calculation. The best DMC estimate, De = 829(64) cm−1, compares well with the experimental value of 839(10) cm−1 but is lower than values from the best basis‐set calculations. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
The characterisation of selected antidepressant drugs using electrospray ionisation with ion trap mass spectrometry and with quadrupole time‐of‐flight mass spectrometry and their determination by high‐performance liquid chromatography/electrospray ionisation tandem mass spectrometry
Authors: Smyth W. Franklin , Leslie Julian C. , McClean Stephen , Hannigan Bernadette , McKenna Hugh P. , Doherty Bernadette , Joyce Clare , O'Kane Edmund
Published: April 2006

The electrospray ionisation ion trap tandem mass spectrometry (ESI‐MSn) of selected antidepressant drugs, i.e., citalopram, fluoxetine, mirtazapine, paroxetine, sertraline, and venlafaxine, has been investigated. Sequential product ion fragmentation experiments (MSn) have been performed in order to elucidate the degradation pathways for the [M+H]+ ions and their predominant product ions. These MSn experiments show certain characteristic fragmentations in that functional groups are generally cleaved from the ring systems as molecules such as H2O, amines and phenols. When an aromatic entity is present in a drug molecule together with a nitrogen‐containing saturated ring structure as with mirtazapine, fragmentation initially occurs at the latter ring with the former being predictably resistant to fragmentation. Also, when an amine‐containing drug molecule such as fluoxetine also contains a functional group, which liberates a phenol with a significantly lower ΔH value than that of the corresponding amine, the phenol is preferentially liberated. The structures of product ions proposed for ESI‐MSn can be supported by electrospray ionisation quadrupole‐time‐of‐flight tandem mass spectrometry (ESI‐QToF‐MS/MS). These molecules can be identified and determined in mixtures at low ng/mL concentrations by the application of high‐performance liquid chromatography/electrospray ionisation tandem mass spectrometry (HPLC/ESI‐MS2), which can also be used for their analysis in hair samples. Copyright © 2006 John Wiley & Sons, Ltd.
The factors influencing access to health and social care in the farming communities of County Down, Northern Ireland
Authors: HEENAN DEIRDRE
Published: April 2006

Against a background of limited previous research, this paper examines the access to health and social care among older people in the farming communities of County Down, Northern Ireland. In-depth interviews were conducted with 45 people aged 60 or more years living on family farms to collect information about health care needs and service use and adequacy. In addition, interviews with service providers provided information on their perceptions of the farming communities' needs. The findings indicate that there are specific rural dimensions of access to services and that among the respondents there was substantial unmet need. For many farming families, using services is determined by much more than being able to reach them physically. The lack of reliable information, the culture of stoicism and the absence of appropriate services impeded obtaining effective support. Recent health care policies and strategies have stressed the importance of developing local services that are responsive to need in consultation with service users, but there is worryingly little evidence that this has occurred. It is concluded that if effective outcomes are to be achieved, policies must recognise the specific characteristics of rural populations and be sensitive to the needs, attitudes and expectations of farming families. The current lack of understanding about the distinct needs of these communities at present exacerbates the isolation and marginalisation of already vulnerable older people.
Crisis Intervention after the Tsunami in Phuket and Khao Lak
Authors: Bronisch Thomas , Maragkos Markos , Freyer Christoph , Müller-Cyran Andreas , Butollo Willi , Weimbs Regina , Platiel Peter
Published: April 2006

After the Tsunami disaster in Southeast Asia, India, Sri Lanka, and Africa, the German government set up a crisis task force that implemented crisis-intervention teams covering Thailand (Phuket and Khao Lak), Sri Lanka, and Sumatra. Two crisis teams were sent to Phuket; the first one on 28 December 2004, and the second one on 3 January 2005, each for an average of 1 week. This intervention was primarily for the benefit of German citizens and their expatriates and relatives caught up in a major catastrophe as well as the German helpers. This article describes the organizational structures of the German crisis intervention, protective factors for the helpers, psychiatric syndromes - often acute traumata, the problems of the identification process for relatives, and crisis intervention itself. Consequences for further crisis intervention after natural disasters are discussed.
Global energy confinement scaling predictions for the kinetically stabilized tandem mirror
Authors: Pratt J. , Horton W.
Published: April 2006

Transport is studied for the kinetically stabilized tandem mirror, an attractive magnetic confinement device for achieving a steady-state burning plasma. For a magnetohydrodynamic stable system, three different radial transport models with Bohm, gyro-Bohm, and electron temperature gradient (ETG) scaling are derived. As a conservative estimate, numerical coefficients in the models are taken to be consistent with tokamak and stellarator databases. The plug mirrors create an ambipolar potential that controls end losses, whereas radial losses are driven by drift wave turbulence, which lowers the electron temperature through radially trapped particle modes and ETG transport losses. The radial transport equations are analyzed, taking into account the Pastukhov energy and particle end losses. For mirror ratio Rm=9 and a large density ratio between plug and central cell regions, there is a high axial ion confinement potential ϕi∕Ti⪢1, as demonstrated in the GAMMA-10 by Cho et al. [Nucl. Fusion 45, 1650 (2005)]. Profiles and total energy confinement times are calculated for a proof-of-principle experiment (length L=7m, central cell magnetic field B=0.28T, and radius a=1m) and for a test reactor facility (L=30m, B=3T, a=1.5m). For these parameter sets, radial loss dominates the end losses except in the low temperature periphery. In the limit of negligible radial losses, ideal ignition occurs at Ti=7.6keV from the two-body power end losses. The transport suppressing rotation rate is well below the sonic value and scales similarly to biased wall rotation rates in the Large Plasma Device experiments [Horton et al., Phys. Plasmas 12, 022303 (2005)]. Simulation results show that the positive dependence of electron radial transport with increasing electron temperature stabilizes the thermal instabilities giving steady state with Ti=30–60keV and Te=50–150keV with a fusion amplification Q of order 1.5 to 5.0.
Dynamical correlations in Brownian hard rods
Authors: Penna F. , Tarazona P.
Published: April 2006

We analyze the time decay of small amplitude density perturbations in systems of highly packed Brownian hard rods, relaxing towards a uniform density distribution. The results of Brownian dynamics simulations and those of the deterministic dynamic density functional (DDF) theory, are contrasted with a new theoretical approach beyond the DDF assumptions. We characterize dynamical correlation modes which, having the lowest relaxation time, determine the late time evolution of the system. The spectrum of possible time decays has a continuous band structure, with pockets of discrete values, near the minima of the DDF results, where the validity of that theory appears to be well established.
Kinesin 5–independent poleward flux of kinetochore microtubules in PtK1 cells
Authors: Cameron Lisa A. , Yang Ge , Cimini Daniela , Canman Julie C. , Kisurina-Evgenieva Olga , Khodjakov Alexey , Danuser Gaudenz , Salmon E.D.
Published: April 2006

Forces in the spindle that align and segregate chromosomes produce a steady poleward flux of kinetochore microtubules (MTs [kMTs]) in higher eukaryotes. In several nonmammalian systems, flux is driven by the tetrameric kinesin Eg5 (kinesin 5), which slides antiparallel MTs toward their minus ends. However, we find that the inhibition of kinesin 5 in mammalian cultured cells (PtK1) results in only minor reduction in the rate of kMT flux from ∼0.7 to ∼0.5 μm/min, the same rate measured in monopolar spindles that lack antiparallel MTs. These data reveal that the majority of poleward flux of kMTs in these cells is not driven by Eg5. Instead, we favor a polar “pulling-in” mechanism in which a depolymerase localized at kinetochore fiber minus ends makes a major contribution to poleward flux. One candidate, Kif2a (kinesin 13), was detected at minus ends of fluxing kinetochore fibers. Kif2a remains associated with the ends of K fibers upon disruption of the spindle by dynein/dynactin inhibition, and these K fibers flux.
KIR3DL3 allelic diversity: six new alleles exhibit both conservative and non‐conservative substitutions
Authors: Steiner N. K. , Hurley C. K.
Published: April 2006

KIR3DL3 alleles were characterized in two families and one unrelated individual. Based on exon 2–9 nucleotide sequences, six novel alleles, 3DL3*00402, *005, *006, *007, *00801, *00802, were identified bringing the total number of known alleles to 11. Compared with 3DL3*001, the six new alleles differ by from three to nine nucleotides and from three to four amino acids. The new alleles double the number of known polymorphic positions to 18 with variation in exons encoding the extracellular domains, transmembrane region, and a portion of the cytoplasmic tail. Many of the nucleotide substitutions are shared among alleles of 3DL3 or other KIR loci, but five were found only in single 3DL3 alleles. Comparison of intron sequences among individuals carrying the same allele showed a modest number of substitutions with the exception of 3DL3*001 which differed substantially in its intron sequences. Two alleles sharing coding region sequences, 3DL3*00201 and 3DL3*00202, were also substantially different in intron sequences.
Corporate Governance and Financial Constraints on Strategic Turnarounds*
Authors: Filatotchev Igor , Toms Steve
Published: April 2006

abstract The paper extends theRobbins and Pearce (1992) two‐stage turnaround response model to include governance factors. In addition to retrenchment and recovery, the paper proposes the addition of a realignment stage, referring specifically to the realignment of expectations of principal and agent groups. The realignment stage imposes a threshold that must be crossed before the retrenchment and hence recovery stage can be entered. Crossing this threshold is problematic to the extent that the interests of governance‐stakeholder groups diverge in a crisis situation. The severity of the crisis impacts on the bases of strategy contingent asset valuation leading to the fragmentation of stakeholder interests. In some cases the consequence may be that management are prevented from carrying out turnarounds by governance constraints. The paper uses a case study to illustrate these dynamics, and like the Robbins and Pearce study, it focuses on the textile industry. A longitudinal approach is used to show the impact of the removal of governance constraints. The empirical evidence suggests that such financial constraints become less serious to the extent that there is a functioning market for corporate control. Building on governance research and turnaround literature, the paper also outlines the general case necessary and sufficient conditions for successful turnarounds.
Exploring Problems with Function Analysis. Experimental Insights for Team Management
Authors: Moehrle Martin G. , Wenzke Sven
Published: April 2006

Problem analysis is an important, but mainly neglected part of the problem‐solving process. The theory of inventive problem solving (TRIZ) offers an instrument called function analysis to conduct problem analysis, which is especially useful for exploring a problem. This process is based on an idea applied in different creativity techniques, saying that behind one problem statement many problem formulations may occur, which allows for evaluation and selection of those problem formulations before looking for problem solutions. The application of function analysis as a tool for teams is recommended for a number of reasons. In so doing so, two main questions arise: (i) Should function analysis be used with the help of an external moderator? and: (ii) Should it be applied with currently available special software? After introducing the basics of function analysis this article provides key findings deducted from an experiment addressing these questions. An important result is the remarkable learning effect, which occurs while using function analysis in teams. By applying function analysis in R&D, companies will be able to get deeper and team‐based problem explorations, which may lead to maturing problem solutions.