bluuebunny/crossref_metadata_2025 huggingface dataset:
Exact convergence rate of an Erdös-Rényi strong law for moving quantiles
Authors: Deheuvels Paul , Steinebach Josef
Published: April 2006

Consider a sequence U1, U2, · ·· of i.i.d. uniform (0, 1)-random variables. For fixed α ∈ (0, 1), let U(n, K) denote the [Kα]th order statistic of the subsample Un+1, · ··, Un+K, and set . Book and Truax (1976) proved the following analogue of the Erdös-Rényi (1970) strong law of large numbers: for α < u < 1 and C = C(α, u) such that −1/C = αlog(u/α)+ (1 – α)log((l – u)/(1 –α)), it holds almost surely that

In view of the Deheuvels–Devroye (1983) improvements of the original Erdös-Rényi law, we determine the lim inf and lim sup of

where K = [C log N]. This improves (∗), showing that it holds with a best-possible convergence rate of order O(log log N/log N). Using the quantile transformation the result can be extended to a general i.i.d. sequence X1, X2, · ·· with d.f. F satisfying a strict monotonicity condition.
Some remarks on the Rayleigh process
Authors: Giorno V. , Nobile A. G. , Ricciardi L. M. , Sacerdote L.
Published: April 2006

The transition p.d.f. for a one-dimensional Rayleigh process in the presence of an absorption condition or a zero-flux condition in the origin is obtained in closed form. The first-passage-time problem through an arbitrary constant boundary is then considered and the moment-generating function is determined. In some particular cases the first-passage-time p.d.f. is explicitly derived. Use of some of these results is finally made to obtain the transition p.d.f. of the affine drift-linear infinitesimal-variance diffusion process when the origin is an entrance or a regular boundary in the presence of a reflection condition.
A simulation study of Sylvester's problem in three dimensions
Authors: Do Kim-Anh , Solomon Herbert
Published: April 2006

This note gives estimates of solutions to the Sylvester problem in three dimensions. These results suggest that the solutions in four and higher dimensions are very close to the solution for the n -dimensional sphere which is known.
Explicit formulas for the characteristics of the M/M/2/2 queue with repeated attempts
Authors: Hanschke Thomas
Published: April 2006

In this paper we study the M/M/2/2 queue with repeated attempts. It is shown that the part generating functions of the steady state probabilities can be expressed in of generalized hypergeometric unctions.
A note on the two-sex population process
Authors: Gani J. , Tin Pyke
Published: April 2006

This paper considers the two-sex birth-death model {X(t), Y(t); t ≧ 0}; an explicit solution is obtained for its probability generating function. It is shown that moments of the process can be found directly from the Kolmogorov forward equations for the probabilities. An integral equation approach is also used to throw light on the structure of the process.
M/M/∞ transience revisited
Authors: Preater J.
Published: April 2006

We take a fresh look at some transient characteristics of an M/M/∞ queue, studied previously by Guillemin and Simonian using delicate complex analysis. Along the way we obtain the Laplace transform of the joint distribution of the duration, number of arrivals and swept area associated with a busy period of an M/M/1 queue.
On the prediction of fractional Brownian motion
Authors: Gripenberg Gustaf , Norros Ilkka
Published: April 2006

Integration with respect to the fractional Brownian motion Z with Hurst parameter is discussed. The predictor is represented as an integral with respect to Z, solving a weakly singular integral equation for the prediction weight function.
On a property of a refusals stream
Authors: Abramov Vyacheslav M.
Published: April 2006

This paper consists of two parts. The first part provides a more elementary proof of the asymptotic theorem of the refusals stream for an M/GI/1/n queueing system discussed in Abramov (1991a). The central property of the refusals stream discussed in the second part of this paper is that, if the expectations of interarrival and service time of an M/GI/1/n queueing system are equal to each other, then the expectation of the number of refusals during a busy period is equal to 1. This property is extended for a wide family of single-server queueing systems with refusals including, for example, queueing systems with bounded waiting time.
On weak convergence within a Lorenz ordering family of distributions
Authors: Lin Gwo Dong
Published: April 2006

We first introduce a Lorenz ordering family of distributions which are related to the gamma distribution, and then prove that the weak convergence within this family is equivalent to the convergence of each moment sequence of positive orders to the corresponding moment of the limiting distribution.
Stochastic comparisons of order statistics under multivariate imperfect repair
Authors: Hu Taizhong
Published: April 2006

A monotone coupling of order statistics from two sets of independent non-negative random variables Xi, i = 1, ···, n, and Yi, i = 1, ···, n, means that there exist random variables X′i, Y′i, i = 1, ···, n, on a common probability space such that , and a.s. j = 1, ···, n, where X(1) ≦ X(2) ≦ ·· ·≦ X(n) are the order statistics of Xi, i = 1, ···, n (with the corresponding notations for the X′, Y, Y′ sample). In this paper, we study the monotone coupling of order statistics of lifetimes in two multi-unit systems under multivariate imperfect repair. Similar results for a special model due to Ross are also given.
Limit theorems for stochastically perturbed dynamical systems
Authors: Łoskot Krzysztof , Rudnicki Ryszard
Published: April 2006

We consider a discrete-time stochastically perturbed dynamical system on the Polish space given by the recurrence formula Xn = S(Xn–1, Yn), where Yn are i.i.d. random elements. We prove the existence of unique stationary measure and versions of classical limit theorems for the process (Xn).
A general formula for the downtime distribution of a parallel system
Authors: Haukås Harald , Aven Terje
Published: April 2006

In this paper we study the problem of computing the downtime distribution of a parallel system comprising stochastically identical components. It is assumed that the components are independent, with an exponential life-time distribution and an arbitrary repair time distribution. An exact formula is established for the distribution of the system downtime given a specific type of system failure scenario. It is shown by performing a Monte Carlo simulation that the portion of the system failures that occur as described by this scenario is close to one when we consider a system with quite available components, the most common situation in practice. Thus we can use the established formula as an approximation of the downtime distribution given system failure. The formula is compared with standard Markov expressions. Some possible extensions of the formula are presented.
Economies of scale in queues with sources having power-law large deviation scalings
Authors: Duffield N. G.
Published: April 2006

We analyse the queue QL at a multiplexer with L sources which may display long-range dependence. This includes, for example, sources modelled by fractional Brownian motion (FBM). The workload processes W due to each source are assumed to have large deviation properties of the form P[Wt/a(t) > x] ≈ exp[– v(t)K(x)] for appropriate scaling functions a and v, and rate-function K. Under very general conditions limL→xL–1 log P[QL > Lb] = – I(b), provided the offered load is held constant, where the shape function I is expressed in terms of the cumulant generating functions of the input traffic. For power-law scalings v(t) = tv, a(t) = ta (such as occur in FBM) we analyse the asymptotics of the shape function limb→xb–u/a(I(b) – δbv/a) = vu for some exponent u and constant v depending on the sources. This demonstrates the economies of scale available though the multiplexing of a large number of such sources, by comparison with a simple approximation P[QL > Lb] ≈ exp[−δLbv/a] based on the asymptotic decay rate δ alone. We apply this formula to Gaussian processes, in particular FBM, both alone, and also perturbed by an Ornstein–Uhlenbeck process. This demonstrates a richer potential structure than occurs for sources with linear large deviation scalings.
On the time a Markov chain spends in a lumped state
Authors: Norberg Tommy
Published: April 2006

The sojourn time that a Markov chain spends in a subset E of its state space has a distribution that depends on the hitting distribution on E and the probabilities (resp. rates in the continuous-time case) that govern the transitions within E. In this note we characterise the set of all hitting distributions for which the sojourn time distribution is geometric (resp. exponential).
Research Review: Child protection referrals and minority ethnic children and families
Authors: Chand Ashok , Thoburn June
Published: April 2006

This paper reviews the research on the referral of minority ethnic children to child and family social work teams because of child protection concerns. Specifically, it focuses on those studies that have researched the referral stage of the child ‘in need’ and child protection systems, and explored differences in patterns of referral between the main ethnic groups that make up the UK population.
Associations between plasma adiponectin concentrations and liver histology in patients with nonalcoholic fatty liver disease
Authors: Targher Giovanni , Bertolini Lorenzo , Rodella Stefano , Zoppini Giacomo , Scala Luca , Zenari Luciano , Falezza Giancarlo
Published: April 2006

Objectives  To explore associations between plasma adiponectin concentrations and liver histology in patients with nonalcoholic fatty liver disease (NAFLD).

Design and patients  In a cross‐sectional study, we enrolled 60 consecutive NAFLD patients and 60 age‐, sex‐ and body mass index (BMI)‐matched healthy controls.

Measurements  NAFLD (by liver biopsy), plasma adiponectin concentrations, insulin resistance (by homeostasis model assessment, HOMA‐IR) and metabolic syndrome (MetS) features.

Results  NAFLD patients had a marked decrease in plasma adiponectin concentration (6·1 ± 2·8 vs. 13·6 ± 3·8 µg/ml, P < 0·001) compared with matched controls. MetS, as defined by the Adult Treatment Panel III (ATP III) criteria, and its individual components were more frequent among NAFLD patients. The marked differences in adiponectin concentrations that were observed between the groups were little affected by adjustment for age, sex, BMI, HOMA‐IR score and MetS components. Notably, decreased adiponectin levels were closely associated with the degree of hepatic steatosis, necroinflammation and fibrosis (P < 0·001 for all) among NAFLD patients. By logistic regression analysis, low adiponectin levels independently predicted hepatic steatosis [odds ratio (OR) 2·3, 95% confidence interval (CI) 1·5–5·8, P < 0·001] and necroinflammation (OR 3·1, 95% CI 1·9–7, P < 0·001), but not fibrosis (P = 0·07), after adjustment for age, sex, BMI, HOMA‐IR and MetS components.

Conclusions  NAFLD patients have markedly lower plasma adiponectin concentrations than control subjects. Low adiponectin levels are strongly associated with the severity of liver histology, thus further supporting the hypothesis that adiponectin might be involved in the development of NAFLD.
Woody biomass production during the second rotation of a bio‐energyPopulusplantation increases in a future high CO2world
Authors: LIBERLOO MARION , CALFAPIETRA CARLO , LUKAC MARTIN , GODBOLD DOUGLAS , LUO ZHI‐BIN , POLLE ANDREA , HOOSBEEK MARCEL R. , KULL OLEVI , MAREK MICHAL , RAINES CHRISTINE , RUBINO MAURO , TAYLOR GAIL , SCARASCIA‐MUGNOZZA GIUSEPPE , CEULEMANS REINHART
Published: April 2006

The quickly rising atmospheric carbon dioxide (CO2)‐levels, justify the need to explore all carbon (C) sequestration possibilities that might mitigate the current CO2increase. Here, we report the likely impact of future increases in atmospheric CO2on woody biomass production of three poplar species (Populus albaL. clone 2AS‐11,Populus nigraL. clone Jean Pourtet andPopulus×euramericanaclone I‐214). Trees were growing in a high‐density coppice plantation during the second rotation (i.e., regrowth after coppice; 2002–2004; POPFACE/EUROFACE). Six plots were studied, half of which were continuously fumigated with CO2(FACE; free air carbon dioxide enrichment of 550 ppm). Half of each plot was fertilized to study the interaction between CO2and nutrient fertilization. At the end of the second rotation, selective above‐ and belowground harvests were performed to estimate the productivity of this bio‐energy plantation. Fertilization did not affect growth of the poplar trees, which was likely because of the high rates of fertilization during the previous agricultural land use. In contrast, elevated CO2enhanced biomass production by up to 29%, and this stimulation did not differ between above‐ and belowground parts. The increased initial stump size resulting from elevated CO2during the first rotation (1999–2001) could not solely explain the observed final biomass increase. The larger leaf area index after canopy closure and the absence of any major photosynthetic acclimation after 6 years of fumigation caused the sustained CO2‐induced biomass increase after coppice. These results suggest that, under future CO2concentrations, managed poplar coppice systems may exhibit higher potential for C sequestration and, thus, help mitigate climate change when used as a source of C‐neutral energy.
Does exposure to di(2‐ethylhexyl) phthalate in pre‐pubertal boars affect semen quality post‐puberty?
Authors: Spjuth Linda , Ljungvall Karl , Saravia Fernando , Lundeheim Nils , Magnusson Ulf , Hultén Fredrik , Rodríguez‐Martínez Heriberto
Published: April 2006

Di(2‐ethylhexyl) phthalate (DEHP), a plastic softener used in polyvinyl chloride (PVC) products, has been ascribed to have toxic effects on animal reproduction. The present study aimed at determining potential late effects of pre‐pubertal oral exposure to DEHP on semen quality in young pigs. Ten pairs of cross‐bred male siblings were used. One brother in each pair became, at random, the test animal while the other acted as control. Test males were exposed to 300 mg/kg body weight (bw) of DEHP administered orally three times a week from 3 to 7 weeks of age. The control group was given placebo (water). Semen analyses started when the boars reached 6 months of age, with semen collected twice weekly, until animals were 9 months of age. Semen was evaluated for ejaculate volume, sperm concentration, total sperm count, sperm motility, sperm morphology (including presence of cells other than spermatozoa) and sperm plasma membrane integrity. Total sperm motility tended to be lower while local motility was higher in the DEHP‐exposed group compared with controls (p = 0.07) when assessed by computer‐assisted sperm analysis. The DEHP‐exposed group had a significantly (p < 0.05) lower percentage of spermatozoa with tailless, defective heads (at 7–8 months of age) and double‐folded tails (at 6–7, 7–8 and 6–9 months of age), compared with controls (albeit always under 5%). In summary, there were no obvious adverse effects of early oral exposure to 300 mg/kg bw of DEHP on sperm output and sperm quality in post‐pubertal young boars.
Effect of nurse‐led gut‐directed hypnotherapy upon health‐related quality of life in patients with irritable bowel syndrome
Authors: Smith Graeme D
Published: April 2006

Aims and objectives.  This study quantified health‐related quality of life in a group of irritable bowel syndrome patients and measures changes following a treatment programme of nurse‐led gut‐directed hypnotherapy.

Background.  It is well recognized that health‐related quality of life can be severely impaired in patients suffering form the irritable bowel syndrome. Current conventional treatment for irritable bowel syndrome is often unsatisfactory. In contrast it has been shown that gut‐directed hypnotherapy is an effective treatment of irritable bowel syndrome with up to three‐quarters of patients reporting symptomatic improvement.

Design/method.  Seventy‐five patients (55 females/20 males, median age 37·1 years, age range 18–64) comprised the study group. Physical symptoms of irritable bowel syndrome were recorded using seven‐day diary cards. On presentation the predominant symptoms were abdominal pain (61%), altered bowel habit (32·5%), and abdominal distension/bloating (6·5%) in the patient group. An irritable bowel syndrome quality of life questionnaire was used to define health‐related quality of life. Psychological well‐being was measured using the Hospital Anxiety and Depression Scale. Data analysis was carried out using MINITAB, Release 12 for Windows.

Results.  Physical symptoms statistically improved after hypnotherapy. There were also significant statistical improvements (P < 0·001) in six of the eight health‐related quality of life domains measured (emotional, mental health, sleep, physical function, energy and social role). These improvements were most marked in female patients who reported abdominal pain as their predominant physical symptom. Anxiety and depression improved following treatment.

Conclusion.  Gut‐directed hypnotherapy has a very positive impact on health‐related quality of life with improvements in psychological well‐being and physical symptoms. It appears most effective in patients with abdominal pain and distension.

Relevance to clinical practice.  This study demonstrates that by integrating complementary therapies into conventional care that gastrointestinal nurses have a potential role in the management of irritable bowel syndrome.
Hybrid transcription system for controlled plastid transgene expression
Authors: Buhot Laurence , Horvàth Eva , Medgyesy Peter , Lerbs‐Mache Silva
Published: April 2006

Plastid transformation technologies have developed rapidly over the last few years, reflecting their value in the study of the principal mechanisms of plastid gene expression and commercial interest in using plastids as bioreactors. Application of this technology is still limited by the difficulty of obtaining regulated, selective expression of plastid transgenes. The plastid genome is transcribed by two different types of RNA polymerase. One of them is of the eubacterial type of polymerase, and its subunits are encoded in the plastid genome [plastid‐encoded RNA polymerase (PEP)]. The other one is of the phage type and nucleus‐encoded [nucleus‐encoded RNA polymerase (NEP)]. To obtain selective transgene expression, we have made use of the similarities and differences between the eubacterial and the plastid eubacterial type transcription systems. We created a hybrid transcription system in which the transgene is placed under the control of a eubacterial promoter which does not exist in the plastid genome and which is not recognized by the plastid endogenous transcriptional machinery. Selective transcription of the transgene is achieved by the supply of a chimeric transcription factor that interacts with PEP and directs it specifically to the foreign eubacterial‐type transgene promoter. This hybrid transcription system could be used for biotechnological and fundamental research applications as well as in the characterization of the evolutionary differences between the eubacterial and the plastid eubacterial‐type transcription systems.
The Behavioral Significance of Male Body Size in the Tarantula Hawk Wasp Hemipepsis ustulata (Hymenoptera: Pompilidae)
Authors: Alcock John , Kemp Darrell J.
Published: April 2006

Large males of the tarantula hawk wasp Hemipepsis ustulata appear to have an advantage in the competition for mates. Large males are more likely to acquire perch territories used to scan for incoming receptive females and territorial males appear more likely to mate than non‐territorial males. In addition, among the males that do secure a mate, those that intercept a female on a territory are larger than those that do so elsewhere. Despite the mating advantages apparently enjoyed by larger males of this species, average male size has remained essentially constant over the last 25 yr. Moreover, larger males are not seen to employ certain competitive tactics that might otherwise enhance their reproductive success. Thus, larger males did not preferentially visit the most popular landmark territory compared to a site that attracted fewer visitors overall. Nor were larger males more likely to return to potential territories after marking, capture, and release, either immediately or on a subsequent day. Finally, although large males made up a significantly greater proportion of the males captured at two territories as the 2005 flight season progressed, over all the years of the study, receptive females have not been concentrated in the latter part of the flight seasons.
Anesthesia and Fanconi anemia: a case report and review of literature
Authors: JACOB REBECCA , VENKATESAN THIRUVENKATARAJAN
Published: April 2006

Fanconi anemia (FA) is the most frequently reported of the rare inherited bone marrow failure syndromes. It is an autosomal recessive chromosomal instability disorder, which is characterized by congenital abnormalities, defective hemopoiesis and a high risk of developing acute myeloid leukemia and certain solid tumors (1). We report the anesthetic management for a Hickman catheter insertion in a 4.5‐year‐old girl with this condition. Possible anesthetic implications in the presence of FA are discussed.
Work of breathing in anesthetized infants increases when a breathing system filter is used
Authors: BELL GRAHAM T. , MARTIN KERRYN M. , BEATON STEPHEN
Published: April 2006

Background : There are concerns that the inclusion of a pediatric heat and moisture exchange filter (HMEF) is in a breathing system may cause an unacceptable increase in the work of breathing. This study is the first study to objectively measure the increase in work of breathing in the infant population when an HMEF is added to the pediatric breathing circuit.

Methods : Ten patients weighing 3–8 kg were studied in a randomized crossover trial. Work of breathing was analyzed using the integral of pressure–volume loops.

Results : The median increase in the work of breathing associated with the addition of an HMEF was 279 mJ·min−1 (95% CI, 165–903 mJ·min−1). This equates with a percentage increase of 43% (95% CI, 25–138%).

Conclusions : Because of the substantial increase in the work of breathing with an HMEF attached to the tracheal tube, consideration should be given to alternative means of humidification and filtration during periods of spontaneous ventilation in small infants.
Structural Laplace Transform and Compound Autoregressive Models
Authors: Darolles Serge , Gourieroux Christian , Jasiak Joann
Published: April 2006

Abstract. This paper presents a new general class of compound autoregressive (Car) models for non‐Gaussian time series. The distinctive feature of the class is that Car models are specified by means of the conditional Laplace transforms. This approach allows for simple derivation of the ergodicity conditions and ensures the existence of forecasting distributions in closed form, at any horizon. The last property is of particular interest for applications to finance and economics that investigate the term structure of variables and/or of their nonlinear transforms. The Car class includes a number of time‐series models that already exist in the literature, as well as new models introduced in this paper. Their applications are illustrated by examples of portfolio management, term structure and extreme risk analysis.
Partial autocorrelation parameterization for subset autoregression
Authors: McLeod A. I. , Zhang Y.
Published: April 2006

Abstract. A new version of the partial autocorrelation plot and a new family of subset autoregressive models are introduced. A comprehensive approach to model identification, estimation and diagnostic checking is developed for these models. These models are better suited to efficient model building of high‐order autoregressions with long time series. Several illustrative examples are given.
Empirical Evidence on the Role of Trading Suspensions in Disseminating New Information to the Capital Market
Authors: Engelen Peter‐Jan , Kabir Rezaul
Published: April 2006

Abstract:  This paper examines the effect of temporarily suspending the trading of exchange‐listed individual stocks. We evaluate whether regulatory authorities can successfully use the mechanism of trading suspension in forcing companies to disclose new and material information to the capital market. Previous studies on trading suspensions mainly concentrate on North‐American stock markets and find conflicting results. This study utilizes a new data set comprising of firms listed on Euronext Brussels – an important segment of Europe's leading cross‐border exchange. Our results show that suspension is indeed an effective means of disseminating new information. Stock prices adjust completely and instantaneously to the new information released during trading suspensions. We also observe a significant increase in trading volume with the reinstatement of trading. On the other hand, we do not find support for the claim that trading suspensions increase the volatility of stock prices. Overall, our results show the efficacy of trading suspensions in disseminating new information.
Application of mark–recapture methods to lions: satisfying assumptions by using covariates to explain heterogeneity
Authors: Ogutu J. O. , Piepho H.‐P. , Dublin H. T. , Reid R. S. , Bhola N.
Published: April 2006

Accurate estimation of wildlife population size is central to effective management and conservation but is notoriously difficult for rare and cryptic carnivores. Mark–recapture methods can reliably estimate the abundance of large carnivores but are sensitive to departures from the assumption of equal catchability, which is probable for territorial and social carnivores. We empirically analysed how pride area, age and sex, group size and pride size of lionsPanthera leoand possession of a kill affect the performance of the sight–resight method relative to concurrent total counts. We stratified the population by pride area to obtain a better sample size for reliable population size estimation, and determined the composition and size of each pride. Marking and recapture involved merely identifying and re‐identifying individual lions. The per cent of the population marked in each pride area varied from 33.3 to 100. Twenty‐six estimates of pride size for 22 different pride areas and repeat surveys in five pride areas were made between September 1990 and April 1992. The second samples involved sampling with replacement, soBailey's (1952)bias‐corrected estimator for closed populations was applied. Increasing the per cent of the population marked improved accuracy only when the number of lions marked in a pride area was at least seven. Estimates were somewhat poorer when the number marked was less than seven but improved with more markings, but no estimate of population size was biased high. Age, sex, group size, pride size and feeding events all influenced the sightability of lions. Notably, females (>1 year) were sighted or resighted in proportion to their presence in the population, whereas similarly aged males, adults or subadults fluctuated erratically about their population proportions. Sight–resight surveys of territorial and social carnivores are reliable but can be costly and time consuming.
Geographic and gender shape differences in the carapace of Liocarcinus depurator (Brachyura: Portunidae) using geometric morphometrics and the influence of a digitizing method
Authors: Rufino M. M. , Abelló P. , Yule A. B.
Published: April 2006

The current work describes the use of geometric morphometrics in the study of the portunid crab Liocarcinus depurator carapace shape variation along the Mediterranean coast of Spain. As a first step, the differences in shape induced by digitizing the carapace with either a digital camera or a flat bed scanner were investigated. Carapace shape information inferred from the camera images proved different from that obtained from the scanner images. This difference was greater than any shape variation because of crab gender or sample location. Carapace shape was analysed using multiple analysis of covariance (with centroid size as a covariate) of the partial warps and uniform components indicating differences between genders and between sample location; however, significant three‐way interaction implied that such differences were gender and location specific. Landmarks identifying carapace width, carapace length and posterior carapace width showed greatest variation; hence gender and location differences were further analysed through the interrelationships between these linear measures. Regression analysis of the relationship between posterior carapace width and the ratio of carapace width to carapace length indicated clear differences between locations but not between genders. Crabs from the Alborán Sea had proportionally wider posterior carapaces than those from Alicante or North Catalonia. This finding may represent the difference between a southern influx of an Atlantic population distinguishable from a more northerly Mediterranean one, which would be in agreement with the overall oceanographic surface circulation pattern in the western Mediterranean.
Risk Factors and Prediction of Postoperative Delirium in Elderly Hip‐Surgery Patients: Implementation and Validation of a Medical Risk Factor Model
Authors: Kalisvaart Kees J. , Vreeswijk Ralph , De Jonghe Jos F. M. , Van Der Ploeg Tjeerd , Van Gool Willem A. , Eikelenboom Piet
Published: April 2006

OBJECTIVES:To evaluate risk factors for postoperative delirium in a cohort of elderly hip‐surgery patients and to validate a medical risk stratification model.

DESIGN:Prospective cohort study.

SETTING:Medical school–affiliated general hospital in Alkmaar, the Netherlands.

PARTICIPANTS:Six hundred three hip‐surgery patients aged 70 and older screened for risk factors for postoperative delirium.

MEASUREMENTS:Predefined risk factors for delirium were assessed on admission. One point was assigned for each of four risk factors present, resulting in three groups: low, intermediate, and high risk. Baseline screening and assessment included the Mini‐Mental State Examination, the standardized Snellen test for visual impairment, chart review to determine Acute Physiological and Chronic Health Evaluation II score, and blood urea nitrogen to creatinine ratio. The primary outcome was postoperative delirium, as defined using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and Confusion Assessment Method criteria. All patients were screened daily for delirium.

RESULTS:Incidence of delirium was 3.8% in the low‐risk group (P<.001), 11.1% in the intermediate‐risk group (P=.27, relative risk (RR)=3.0), and 37.1% in the high‐risk group (P<.001, RR=9.8). Cognitive impairment at admission had the highest predictive value for postoperative delirium (coefficient of determination=0.15). Contrary to previous findings, age was an independent predictive factor for delirium. Moreover, postoperative delirium was four times as frequent in acute patients as in elective hip‐replacement patients.

CONCLUSION:The medical risk factor model is valid for elderly hip‐surgery patients. Cognitive impairment, age, and type of admission are important risk factors for delirium in this surgical population.
Recombinant factor VIIa in patients with coagulopathy secondary to anticoagulant therapy, cirrhosis, or severe traumatic injury: review of safety profile
Authors: Levy Jerrold H. , Fingerhut Abe , Brott Thomas , Langbakke Irene H. , Erhardtsen Elisabeth , Porte Robert J.
Published: April 2006

BACKGROUND:  In recent years, the hemostatic agent recombinant factor VIIa (rFVIIa) has emerged as a potentially new therapeutic agent for management of coagulopathy in patients with cirrhosis or following severe traumatic injury, a complex problem for clinicians in which standard treatment strategies are not always effective. As with other hemostatic agents, a primary safety concern of rFVIIa therapy is the theoretical possibility that systemic administration could confer an increased risk of thrombotic complications. So far, clinical experience indicates rFVIIa to be a safe treatment for currently approved indications within hemophilia. Little information is available, however, for patient populations outside this clinical setting.

STUDY DESIGN AND METHODS:  This article reviews critical safety data obtained from 13 Novo Nordisk–sponsored clinical trials of rFVIIa in patients with coagulopathy secondary to anticoagulant therapy, cirrhosis, or severe traumatic injury.

RESULTS:  Thrombotic adverse events were reported for 5.3 percent (23/430) of placebo‐treated patients and 6.0 percent (45/748) of patients on active treatment. No significant difference was found between placebo‐treated and rFVIIa‐treated patients with respect to the incidence of thrombotic AEs, either on an individual trial basis or for these trial populations combined (p = 0.57).

CONCLUSION:  An important determinant for the safety profile reported here is likely to be the specific mechanism of action of rFVIIa, shown in experimental studies to be localized to the site of vascular injury where tissue factor is exposed.
Paired in vitro and in vivo comparison of apheresis platelet concentrates stored in platelet additive solution for 1 versus 7 days
Authors: Shanwell Agneta , Diedrich Beatrice , Falker Cecilia , Jansson Berit , Sandgren Per , Sundkvist Lars , Svensson Leif , Vesterinen Mervi , Gulliksson Hans
Published: April 2006

BACKGROUND:  To improve clinical access to platelet concentrates (PCs), prolonging the storage period is one alternative, provided that they are free from bacteria. The quality of platelets (PLTs) stored for 1 versus 7 days was compared by in vitro analyses and in vivo recovery and survival in blood donors.

STUDY DESIGN AND METHODS:  Apheresis PCs from 10 donors were divided and stored in PLT additive solution in 2 equal units for a paired comparison. PLTs in one unit were 111In‐labeled at 1 day of storage, and PLTs in the other unit were labeled after 7 days of storage. PLTs were injected into the donor after labeling and samples were drawn after 30, 60, and 150 minutes and thereafter once a day for 14 days for recovery and survival measurements.

RESULTS:  PLT recovery on Day 7 was 80 percent of the recovery on Day 1 (p  < 0.05), and the survival on Day 7 was 65 percent of survival on Day 1 (p < 0.005). No significant differences were seen regarding mean PLT volume (MPV), pH, pCO2, pO2, bicarbonate, or hypotonic shock response. Lactate increased and lactic dehydrogenase increased slightly, whereas glucose and ATP decreased, but not to a critical level. A significant increase in RANTES (110.7 ± 76.6 vs. 277.6 ± 50.8 pg/106 PLTs [p < 0.005]) and PLT factor 4 (19.9 ± 9.6 vs. 59.8 ± 7.5 IU/106 PLTs [p < 0.0001]) was noticed during storage.

CONCLUSION:  Recovery and survival of PCs stored for 7 days decreased, but met suggested criteria. Analyzed in vitro parameters showed acceptable results. Randomized patient transfusion studies will provide additional verification of the suitability of 7‐day storage of PLTs.
Magnetic resonance imaging determination of extraocular eye muscle volume in patients with thyroid‐associated ophthalmopathy and proptosis
Authors: Kvetny Jan , Puhakka Katriina Bøcker , Røhl Lisbeth
Published: April 2006

Purpose:  Recent studies concerning the association between extraocular muscle (EOM) enlargement in thyroid‐associated ophthalmopathy (TAO) and immunological and clinical activity have not been conclusive, probably due to a lack of uniform imaging methods (ultrasonography, computer tomography [CT] or magnetic resonance imaging [MRI]) and difficulties in the determination of EOM volume. The aim of the present study was to examine the significance of EOM enlargement as established by MRI‐based volume determination, with reference to proptosis and the presence of autoantibodies, clinical activity and the duration of active disease.

Methods:  We determined EOM volume using MRI in 15 patients concomitantly with the determination of TSH, thyroid hormones, thyrotropin receptor antibodies (TRab) thyroid peroxidase antibodies (TPOab) and clinical activity score (CAS) at entry. We also established the duration until cessation of clinically active TAO.

Results:  All 15 patients had bilateral EOM enlargement, but swelling of orbital fatty tissue was absent. Significant correlations between thickness of musculi rectales and proptosis, values of TRab, CAS, and duration of activity were observed.

Conclusion:  Our results support the hypothesis of a role of thyrotropin receptor antibodies in the pathogenesis of TAO and suggest that only EOM enlargement is responsible for proptosis in TAO.
Antidepressants: general practitioners’ opinions and clinical practice
Authors: Rambelomanana S. , Depont F. , Forest K. , Hébert G. , Blazejewski S. , Fourrier‐Réglat A. , Molimard M. , Moore N.
Published: April 2006

Objective:  To describe and compare general practitioners’ (GPs) opinions on antidepressant drugs and their prescriptions to depressed patients.

Method:  Between November 2000 and July 2001 a representative sample of French GPs was asked their opinion of the 15 most prescribed antidepressants, and then to describe the treatments of the current depressive episode of four depressive patients each, their changes and the reasons thereof.

Results:  One hundred and eighty‐one GPs and 778 patients participated. The best‐ranked antidepressants by the GPs were paroxetine, fluoxetine, sertraline and clomipramine for efficacy, and paroxetine, tianeptine, sertraline and fluoxetine for tolerability. In patients, the drugs most often prescribed were fluoxetine, paroxetine, and sertraline. Those least often stopped for intolerance were moclobemide (0%), dosulepine (0%), venlafaxine (4.5%) and citalopram (5.0%), and maprotiline (0%), citalopram (1.7%) and venlafaxine (2.3%) for lack of efficacy. The best predictor for prescription of antidepressants was the GPs’ overall ranking, itself depending on opinions of the tolerability and efficacy of the drug. However, opinions of tolerability and efficacy were not related to the rates of treatment discontinuation for intolerability or inefficacy.

Conclusion:  Prescriber opinion does not seem related to actual product performance.
The PIP5K2A and RGS4 genes are differentially associated with deficit and non‐deficit schizophrenia
Authors: Bakker S. C. , Hoogendoorn M. L. C. , Hendriks J. , Verzijlbergen K. , Caron S. , Verduijn W. , Selten J. P. , Pearson P. L. , Kahn R. S. , Sinke R. J.
Published: April 2006

Several putative schizophrenia susceptibility genes have recently been reported, but it is not clear whether these genes are associated with schizophrenia in general or with specific disease subtypes. In a previous study, we found an association of the neuregulin 1 (NRG1) gene with non‐deficit schizophrenia only. We now report an association study of four schizophrenia candidate genes in patients with and without deficit schizophrenia, which is characterized by severe and enduring negative symptoms. Single‐nucleotide polymorphisms (SNPs) were genotyped in the DTNBP1 (dysbindin), G72/G30 and RGS4 genes, and the relatively unknown PIP5K2A gene, which is located in a region of linkage with both schizophrenia and bipolar disorder. The sample consisted of 273 Dutch schizophrenia patients, 146 of whom were diagnosed with deficit schizophrenia and 580 controls. The strongest evidence for association was found for the A‐allele of SNP rs10828317 in the PIP5K2A gene, which was associated with both clinical subtypes (P = 0.0004 in the entire group; non‐deficit P = 0.016, deficit P = 0.002). Interestingly, this SNP leads to a change in protein composition. In RGS4, the G‐allele of the previously reported SNP RGS4‐1 (single and as part of haplotypes with SNP RGS4‐18) was associated with non‐deficit schizophrenia (P = 0.03) but not with deficit schizophrenia (P = 0.79). SNPs in the DTNBP1 and G72/G30 genes were not significantly associated in any group. In conclusion, our data provide further evidence that specific genes may be involved in different schizophrenia subtypes and suggest that the PIP5K2A gene deserves further study as a general susceptibility gene for schizophrenia.
Slavery and Romanticism
Authors: Carey Brycchan
Published: April 2006

This article surveys the history, literature, and culture of slavery and abolition during the Romantic period. It opens with an outline of the main historical developments from the mid‐eighteenth to the mid‐nineteenth centuries before examining the ways in which slavery was represented and challenged in novels, poems and plays written by both well‐known poets such as Blake and Wordsworth, and by lesser known writers such as Thomas Day and Ann Yearsley. It surveys the role of slavery in music and art, before concluding with a discussion of the historiography and critical literature dealing with slavery, and writing about slavery, in the Romantic era. Suggestions for further reading are included.
Effects of an introduced crayfish, Procambarus clarkii, on the distribution of south‐western Iberian amphibians in their breeding habitats
Authors: J. Cruz Maria , Rebelo Rui , G. Crespo Eduardo
Published: April 2006

The introduction of exotic species in aquatic habitats is one of the causes for the amphibian declines observed worldwide. In the 1970s, the red swamp crayfish Procambarus clarkii was introduced in the southwest Iberian Peninsula, where no native crayfish occur. In this study we assess the effect of P. clarkii presence in the breeding site distribution of each of the 13 southwest Iberian amphibians, while simultaneously accounting for the effects of potentially confounding habitat variables, as well as for the effects of the other large aquatic predators in the study area – predatory fish. Amphibian species richness was lower in places where P. clarkii was present than in places without P. clarkii, regardless of fish presence. After accounting for habitat variables and fish, crayfish presence was a negative predictor of the breeding probability for all urodeles (Pleurodeles waltl, Salamandra salamandra, Triturus boscai and T. marmoratus) and for two anurans (Pelobates cultripes and Bufo bufo). The majority of the species affected usually breed in temporary ponds without fish, but that may be colonized by the crayfish. The ongoing expansion of P. clarkii may eventually lead to a growing isolation of amphibian populations and ultimately to local extinctions and a permanent alteration of the amphibian communities in southwest Iberian Peninsula.
Prediction of hepatic clearance using cryopreserved human hepatocytes: a comparison of serum and serum-free incubations
Authors: Blanchard Nadège , Hewitt Nicola J , Silber Paul , Jones Hannah , Coassolo Philippe , Lave Thierry
Published: April 2006

Cryopreserved human hepatocytes have been used to predict hepatic in-vivo clearance. Physiologically-based direct scaling methods generally underestimate human in-vivo hepatic clearance. Cryopreserved human hepatocytes were incubated in 100% serum and in serum-free medium to predict the in-vivo hepatic clearance of six compounds (phenazone (antipyrine), bosentan, mibefradil, midazolam, naloxone and oxazepam). Monte Carlo simulations were performed in an attempt to incorporate the variability and uncertainty in the measured parameters to the prediction of hepatic clearance. The intrinsic clearance (CLint) and the associated variability of the six compounds decreased in the presence of serum and the values were reproducible across donors. The predicted CLhep, in-vivo obtained with hepatocytes from donors incubated in serum was more accurate than the prediction obtained in the absence of serum. For example, the CLhep, in-vivo of mibefradil in donor GNG was 4.27 mL min−1 kg−1 in the presence of serum and 0.46 mL min−1 kg−1 in the absence of serum (4.88 mL min−1 kg−1 observed in-vivo). Using the results obtained in this study together with an extended data set (26 compounds), the clearance of 77% of the compounds was predicted within a 2-fold error in the absence of serum. In the presence of serum, 85% of the compounds were successfully predicted within a 2-fold error. In conclusion, cryopreserved human hepatocyte suspensions represented a convenient and predictive model to assess human drug clearance.
Social and emotional characteristics of adults seeking a cochlear implant and their spouses
Authors: Knutson John F. , Johnson Abigail , Murray Kathleen T.
Published: April 2006

Objectives. Because past research has shown that benefits of cochlear implantation may include a significant decrease in psychological and emotional difficulties, this study examined whether persons seeking cochlear implants in recent years differed psychologically from those referred in the early 1980s. A second objective was to explore mechanisms by which profound deafness could contribute to psychological and emotional difficulties for implant candidates and their spouses.

Methods. 178 cochlear implant candidates referred from 1981 to 1998 at the University of Iowa Hospitals completed a standard battery of psychological tests and questionnaires. The sample was divided into six 3‐year cohorts and compared on standardized measures of psychological and emotional adjustment, and in participation in social and non‐social activities. Spouses of implant candidates completed a similar assessment.

Results. The sample was characterized by elevations in depression, social introversion, suspiciousness, and social anxiety and loneliness. There were no significant differences among cohorts across time except for an increase in expectations for implant success. Spouses also evidenced elevated levels of psychological distress. Hearing status was associated with significant differences in social activity participation. A paradoxical interaction was found between marital status and deafness.

Conclusions. There was no evidence that the psychological status of implant candidates is changing across time, suggesting continued psychological benefit for persons receiving cochlear implants. Both candidates and their spouses participated in fewer social activities than normal controls. Findings underscore the complex relation between marital status, deafness, and engagement and participation in positive activities.
A COMPUTER SYSTEM FOR EDITING DIAGNOSTIC KEYS FOR FLORA NORTH AMERICA
Authors: Morse Larry E. , Beaman John H. , Shetler Stanwyn G.
Published: April 2006

Computer programs are being developed and tested for editing dichotomous keys, particularly to meet the challenges offered by the Flora North America Project. An elementary editing system is available for revising previously prepared keys; the new versions are then printed in conventional indented form. An advanced editing system currently being tested improves the efficiency of the process and offers a choice of output formats. For this latter approach the data are stored in three files: a taxon list, a descriptor list, and a numeric representation of the key. A variety of editing procedures are possible, including additions and deletions of taxa, changes in descriptors, and even translation of the key from one language to another. The system is designed for compatibility with the first author's experimental programs for constructing keys and making direct identifications.
TYPIFICATION OF THE FAMILY STILBELLACEAE
Authors: Benjamin C. R.
Published: April 2006

For some years there have been uncertainty and disagreement as to which name, Stilbella Lindau or Stilbum Tode ex Fr., more properly designates a genus of the Fungi Imperfecti and whether Stilbellaceae or Stilbaceae should be used as the family name. In view of the recent conservation of the latter family name for a taxon of phanerogamic plants (30) having as its type the genus Stilbe Bergius (1767), it seems appropriate to review the fungus nomenclatural problem.
HISTORY AND TYPIFICATION OF THE GENERIC NAME CUPHEA (LYTHRACEAE)
Authors: Graham Shirley A.
Published: April 2006

The selection of Cuphea P. Browne as the correct name and author for the genus over the names Parsonsia and Melanium is discussed. The identity of the type species is established as C. decandra Ait. by comparison of the morphology and distribution of possible candidates with the original description of the genus.