bluuebunny/crossref_metadata_2025 huggingface dataset:
Floral and inflorescence effects on variation in pollen removal and seed production among six legume species
Authors: KUDO G. , HARDER L. D.
Published: May 2005

Most flowering plants display multiple flowers, so that the interaction with pollinators that determines their mating success can vary with both the characteristics of individual flowers and aggregate properties of the entire floral display, especially the number of open flowers (floral display size). These effects are seldom examined in concert and their collective consequences for interspecific differences in reproductive performance have not been considered previously.

In this paper, we characterize the relation of pollen removal and seed production to differences in floral and inflorescence characteristics among six species of herbaceous legumes (Fabaceae).

Several aspects of reproductive performance varied significantly among species with either plant traits or aspects of pollinator behaviour that depend on plant traits. Pollinator visitation, as measured by the ratio of pollen removal during 24 h to first‐visit removal, varied positively with both nectar production per flower and floral display size. Bumble‐bees visited more flowers per inflorescence on species with large floral displays, with no increase in the proportion of flowers visited. Pollen removal during a flower's first visit varied negatively among species with the mean number of flowers visited by bees per inflorescence.

These results indicate that floral and inflorescence traits act together to influence both pollinator energetics, which affects a plant species’ attractiveness, and the rate of pollen removal, which should affect pollen export. In contrast, neither pollen removal during 24 h, nor female fecundity varied significantly with floral or display characteristics.
Climatic variability and hemispheric differences in insect cold tolerance: support from southern Africa
Authors: SINCLAIR B. J. , CHOWN S. L.
Published: May 2005

Insects generally survive subzero temperatures by utilizing either freeze tolerance or freeze avoidance. Comparative analyses from a limited data set have indicated that freeze tolerance may be predominant among species at temperate latitudes in the southern hemisphere, while freeze avoidance dominates in the north.

We investigated the cold tolerance strategies of cockroaches and beetles from cold regions in southern Africa, including the Cederberg mountains, the Karoo desert and the Drakensberg mountains.

We found that 8 of 11 species are freeze tolerant.

Overall, 77% of species investigated in the southern hemisphere (n = 27) were freeze tolerant, which is significantly different from the 29% (n = 258) in the north (P < 0·001).

There are regular, unpredictable subzero temperature events in the southern African habitats; such variability appears to be a general feature of many cold habitats in the southern hemisphere, which may lead to the observed interhemispheric discrepancies in cold‐tolerance strategies.
The fitness correlates of scalation asymmetry in garter snakesThamnophis sirtalis parietalis
Authors: SHINE R. , LANGKILDE T. , WALL M. , MASON R. T.
Published: May 2005

In a field population in Manitoba, about 16% of Red‐Sided Garter Snakes (Thamnophis sirtalis parietalis) have a different number of ribs on either side of the body, as indicated by anomalous ventral scales. A study on congenerics shows that this asymmetry reflects disruption of embryogenesis by environmental factors, including suboptimal maternal thermoregulation during pregnancy.

Correlates of this scalation asymmetry in adult snakes can clarify the degree to which (and pathways by which) the thermal environment that an individual experiences during embryogenesis affects its later fitness.

Data on >4000 free‐ranging snakes reveal no significant association between asymmetry and fitness‐related traits such as body size, body condition, locomotor speeds or female ability to resist harassment from males.

However, adult male snakes with scale asymmetry dispersed from the den‐based mating aggregations sooner than did symmetric males. In outdoor arenas, asymmetric males were less able to obtain matings than were symmetric males; and if asymmetric males did mate, they consistently used the hemipenis on the side of the body opposite to their extra rib.

Our data suggest that careful thermoregulation by a female garter snake during pregnancy provides a fitness benefit to her sons after they mature, via sexual selection.
Effects of gut passage on seed germination: do experiments answer the questions they ask?
Authors: SAMUELS I. A. , LEVEY D. J.
Published: May 2005

Frugivorous vertebrates may affect plant fitness by dispersing seeds to sites favourable for establishment and by passing seeds through their gut, thereby altering germination patterns. Although gut passage can inhibit germination, most studies have found that it improves germination rate and/or success.

However, studies that compare seeds passed through a gut to seeds directly removed from a fruit cannot quantify the overall effect of gut passage on seed germination. They address the ecologically narrow question of whether mechanical and/or chemical action in the gut affects germination. They do not address the germination potential of seeds in unconsumed fruits and therefore ignore a common seed fate, deposition in a fruit.

We surveyed 99 studies that included the effect of vertebrate gut passage on germination and found that only 22 included germination from intact fruits. We suggest that the strongest experimental design to evaluate the impact of gut passage should include intact fruits, since release from germination inhibitors and high osmotic pressure are mechanisms that can alter germination.
A multi‐tier approach to identifying environmental stress in altricial nestling birds
Authors: BLAS J. , BAOS R. , BORTOLOTTI G. R. , MARCHANT T. , HIRALDO F.
Published: May 2005

Birds respond to unpredictable events in the environment by releasing corticosterone, which triggers alternate responses to overcome stressful situations. However, it has been questioned whether altricial nestlings perceive and respond to ecological stressors. Although some studies show adrenal responsiveness in non‐precocial species, others report a hyporesponsive period postulated to avoid deleterious effects of corticosterone.

To test whether the environmental surroundings of nestlings modulate their stress levels we used a multi‐tier comparative approach of plasma corticosterone: (1) within an individual, (2) among nestlings within a brood hierarchy, (3) among broods within a colony and (4) among individuals from different colonies.

Nestlings reacted to our protocol by elevating their corticosterone. Baseline levels differed between colonies, and were higher in singleton nestlings compared with two‐ and three‐chick broods, but there were no differences related to within‐brood hierarchies, age or condition index.

Acute levels were higher in older birds, suggesting a developmental change in adrenal responsiveness. Body condition also explained acute levels but only in singleton nestlings, with higher concentrations in heavier birds.

Overall our results indicate that altricial nestlings do respond to a variety of environmental stressors, and variation in aspects of environmental quality (e.g. food supply, parental care) may be associated with the differences in stress.
An analysis of trade‐offs in immune function, body size and development time in the Mediterranean Field Cricket, Gryllus bimaculatus
Authors: RANTALA M. J. , ROFF D. A.
Published: May 2005

Immune defence has recently been viewed as a life‐history trait that shows trade‐offs with other life‐history traits. However, studies exploring correlations between different components of immune defence and other life‐history traits are scarce.

In this study, two measures of immune function, body size, and development time were studied in the Mediterranean Field Cricket, Gryllus bimaculatus.

We found no differences between the sexes, but differences in the correlation between the measure of immune function, development time, and body size. In both sexes, encapsulation rate was negatively correlated with body size and development time, whereas lytic enzyme activity was positively correlated with these two traits. Furthermore, encapsulation rate and lytic activity were themselves negatively correlated.

These results indicate that there is no single trait that can be termed ‘immunocompetence’ and that an understanding of trade‐offs between the different types of immune function and life‐history traits will require a more detailed analysis of the physiological basis of the traits.
Effects of human oviductal in vitro secretion on spermatozoa and search of sperm–oviductal proteins interactions
Authors: QUINTERO ILEANA , GHERSEVICH SERGIO , CAILLE ADRIANA , MUNUCE MARÍA JOSÉ , DANIELE STELLA MARIS , MORISOLI LIDA
Published: May 2005

It has been suggested that oviductal proteins could be involved in modulating sperm function and fertilizing ability through as yet not well‐known mechanisms. The objective of the study was to investigate the pattern of proteins secreted by human oviductal tissue cultures and the effects of their conditioned media (CM) on sperm function under capacitating conditions and in phosphate buffered saline (PBS). In addition, interactions between spermatozoa and oviductal proteins were examined. The oviductal tissue was obtained from pre‐menopausal patients scheduled for hysterectomies because of uterine fibromyoma. Normozoospermic semen samples were obtained from healthy donors. Cultures of human fallopian tissue were carried out and CM were collected for analysis of the de novo production of [35S]‐methionine‐labelled proteins by SDS‐PAGE. Motile spermatozoa were incubated under capacitating conditions and in PBS, with or without CM, and sperm fertilizing ability was assessed by ionophore‐induced acrosome reaction (AR) and the acrosome reaction to ionophore challenge (ARIC) score. The ionophore‐induced AR was evaluated by thePisum sativumtechnique. Sixteen de novo produced proteins were detected in CM. One of these proteins (molecular weight 79 kDa) was detected in extracts from spermatozoa pre‐incubated with CM. Sperm survival and motility were maintained in the presence of CM, although results showed a significant decrease in ARIC score (p < 0.05), with respect to controls. The presence of CM significantly decreased sperm fertilizing ability, without affecting sperm survival. These results suggest that the oviductal secretion could contribute to preserve sperm viability and motility, and to prevent a premature response of spermatozoa to AR inducers.
The effect of paternal heat stress on protein profiles of pre‐implantation embryos in the mouse
Authors: ZHU B. , MADDOCKS S.
Published: May 2005

The study was undertaken to compare the protein profiles of [35S]‐methionine‐labelled control‐sired embryos with heat‐sired embryos at 7, 14 or 21 days after mature fertile B6CBF F1 male mice were kept at 36 ± 0.3 °C and 62 ± 2.7% relative humidity for 24 h. One‐dimensional gel electrophoresis and autoradiographs were used to examine the protein profiles between the two‐cell embryos and the blastocysts. The results obtained demonstrate that paternal heat stress 7 or 14 days earlier did not apparently affect protein patterns of two‐cell embryos, four‐cell to eight‐cell embryos, morulae or blastocysts. However, 21 days earlier, there were changes in protein patterns of two‐cell embryos and abnormal embryos, but not the morulae. To further support and extend these results, two‐dimensional gel electrophoresis and phosphorimaging were employed and the results obtained show that paternal heat stress 21 days before mating affected protein profiles of two‐cell embryos and morulae in the mouse. Together, these findings have indicated that paternal heat stress affects most but not all protein patterns of pre‐implantation embryos, which strongly supports our previous results demonstrating that paternal heat stress significantly reduced the developmental proportion of pre‐implantation embryos in the mouse.
Impact of radio frequency electromagnetic radiation on DNA integrity in the male germline
Authors: AITKEN R. J. , BENNETTS L. E. , SAWYER D. , WIKLENDT A. M. , KING B. V.
Published: May 2005

Concern has arisen over human exposures to radio frequency electromagnetic radiation (RFEMR), including a recent report indicating that regular mobile phone use can negatively impact upon human semen quality. These effects would be particularly serious if the biological effects of RFEMR included the induction of DNA damage in male germ cells. In this study, mice were exposed to 900 MHz RFEMR at a specific absorption rate of approximately 90 mW/kg inside a waveguide for 7 days at 12 h per day. Following exposure, DNA damage to caudal epididymal spermatozoa was assessed by quantitative PCR (QPCR) as well as alkaline and pulsed‐field gel electrophoresis. The treated mice were overtly normal and all assessment criteria, including sperm number, morphology and vitality were not significantly affected. Gel electrophoresis revealed no gross evidence of increased single‐ or double‐DNA strand breakage in spermatozoa taken from treated animals. However, a detailed analysis of DNA integrity using QPCR revealed statistically significant damage to both the mitochondrial genome (p < 0.05) and the nuclear β‐globin locus (p < 0.01). This study suggests that while RFEMR does not have a dramatic impact on male germ cell development, a significant genotoxic effect on epididymal spermatozoa is evident and deserves further investigation.
Maternal steroid enhancement of fetal rabbit gastrointestinal motility
Authors: Sase Masakatsu , Lee Jeong J. , Ross Michael G. , Buchmiller Terry L.
Published: May 2005

Aim: The purpose of the present study was to determine the potential maturational effects of maternal dexamethasone administration on fetal upper gastrointestinal motility.

Methods: Nineteen pregnant rabbits were randomized into two groups (DEX and CONT) and studied on either day 24, 27 or 30 of pregnancy (term 31 days). The DEX group received intramuscular dexamethasone (DEX) 2 days before study and the controls received saline. Under ultrasound guidance, a needle was percutaneously inserted into each fetal stomach and fluorescein, labeled with color‐coded microspheres, was injected. Two hours later, the length of fluorescein travel throughout the small intestine was measured. The percent motility was calculated by dividing the length of fluorescein travel by the total fetal small intestinal length × 100%.

Results: All maternal and fetal rabbits survived. On day 24 the length of fluorescein travel and the percent motility of the DEX group were significantly longer than controls. There were no differences on either day 27 or 30. Fetal growth was significantly suppressed by a single course of DEX at all gestational ages.

Conclusions: Fetal rabbit gastrointestinal motility is significantly increased after prenatal steroids are given early in the last trimester (day 24 of a 31‐day gestation). Although beneficial in end‐organ maturation, the timing of prenatal steroid administration is crucial to minimize its potential detrimental effects on fetal somatic growth.
Evidence on antibiotic prophylaxis for cesarean section alone is not sufficient to change the practices of doctors in a teaching hospital
Authors: Liabsuetrakul Tippawan , Islam Monir
Published: May 2005

Aims: To assess the pattern of prophylactic antibiotic use in cesarean sections, identify factors associated with single‐dose prescriptions as evidence‐based best practice, and evaluate the changes in use of single‐dose compared with multiple‐dose regimens and the variation of use between doctors after dissemination of evidence.

Methods: An analytical descriptive study was conducted. The medical records of 432 women undergoing cesarean section from April to September 2001 after dissemination of evidence in a teaching hospital in Southern Thailand were reviewed. Use of single‐dose prophylactic antibiotic was the main outcome measure. Patterns of prophylactic antibiotics, and factors associated with pregnant women and doctors, were analyzed and compared with baseline data among 463 women undergoing cesarean section in 1998. Multivariate logistic regression with random effects was used for analysis.

Results: After the dissemination of evidence, the rate of single‐dose prescriptions increased from 14.2 to 22.4% (P < 0.01), single‐dose prescriptions decreased for patients who had experienced longer durations of ruptured membranes, and the timing of the administration of antibiotics improved, but multiple‐dose and duration of postoperative prescriptions increased. The variation in prescribing antibiotics between doctors was significant (P < 0.001).

Conclusions: Knowledge of evidence alone does not improve practices uniformly. Consequently, other interventions are necessary to improve practices.
Endometrial adenocarcinoma after liver transplantation
Authors: Tanaka Hidenori , Sato Hirokazu , Konishi Yoshitomo , Fujimoto Toshio , Takahashi Osamu , Tanaka Toshinobu
Published: May 2005

In June 1999, a 50‐year‐old Japanese woman underwent a liver transplant and was started on tacrolimus hydrate. A routine gynecologic examination at that time was unremarkable. In December 2001, the patient was found to suffer from endometrial adenocarcinoma and total abdominal hysterectomy with adnexa was carried out. No significant changes in liver function were observed. However, because fever in the patient of up to 38.5°C continued, the volume of the tacrolimus hydrate was reduced, and then stopped completely. The patient's fever decreased to approximately 36.5°C and she was discharged on the 18th postoperative day. The present case is the first report of endometrial adenocarcinoma in a patient after liver transplantation.
Lipoprotein(a) levels in women with pre‐eclampsia and in normotensive pregnant women
Authors: Baksu Basak , Baksu Alparslan , Davas Inci , Akyol Atif , Gülbaba Günay
Published: May 2005

Aim: To determine if plasma lipoprotein(a) levels are elevated in pre‐eclampsia and if so, their association with the severity of the disease.

Methods: Ninety‐one pre‐eclamptic (48 mild, 43 severe) and 40 healthy normotensive pregnant women at more than 32 gestational weeks were recruited into study. Plasma levels of lipoprotein(a), lipids, total protein, albumin and fibrinogen were measured in all subjects.

Results: All groups were comparable with respect to maternal age, maternal weight, gravidity and parity. Platelet count, total serum protein and albumin levels were significantly decreased, whereas fibrinogen levels significantly increased in the pre‐eclamptic group. There was no difference between the groups with respect to total cholesterol and low‐density lipoprotein levels. In the pre‐eclampsic group, triglyceride and very‐low‐density lipoprotein concentrations were significantly higher, whereas high‐density lipoprotein levels were significantly lower. No difference in serum lipoprotein(a) levels was found between the three groups.

Conclusions: No statistically significant difference existed between normotensive pregnant, and pre‐eclamptic women, with regard to plasma lipoprotein(a) levels. It is improbable that high serum lipoprotein(a) levels are risk factors for the development of pre‐eclampsia; however, elevated triglyceride‐rich lipoproteins might cause endothelial damage leading to pre‐eclampsia.
Case of iatrogenic dysmenorrhea in non‐communicating rudimentary uterine horn and its laparoscopic resection
Authors: Tanaka Yudai , Asada Hironori , Uchida Hiroshi , Maruyama Tetsuo , Kuji Naoaki , Sueoka Koh , Yoshimura Yasunori
Published: May 2005

A case of non‐communicating rudimentary uterine horn is presented and is a characteristic example of the way that surgical treatment can exacerbate dysmenorrhea by blocking retrograde menstruation. There is always some risk of missing the true diagnosis in cases of uterine abnormalities, even by direct inspection, but intraoperative laparoscopic ultrasonography can be an invaluable tool in defining anatomy. As laparoscopic resection has become the standard procedure for the treatment of unicornuate uterus, laparoscopic ultrasonography can be a useful tool for providing anatomical information to the operating surgeon about the patient.
Is laser conization adequate for therapeutic excision of adenocarcinoma in situ of the uterine cervix?
Authors: Akiba Yasuo , Kubushiro Kaneyuki , Fukuchi Takeshi , Fujii Takuma , Tsukazaki Katsumi , Mukai Makio , Nozawa Shiro
Published: May 2005

Aims: To determine the safety of uterine‐preserving operations for adenocarcinoma in situ of the cervix.

Methods: Fifteen cases of adenocarcinoma in situ (AIS) were diagnosed using neodymium:yttrium aluminum garnet (Nd:YAG) laser conization. The accuracy of preconization histology or cytology was evaluated in 15 AIS cases. In these AIS cases, we investigated how far the tumor was located from the squamocolumnar junction (SCJ) and the endocervix. Fourteen cases of the 15 AIS‐affected patients were treated using laser conization alone. These patients were closely followed up.

Results: Precise agreement between preconization diagnosis and conization histology was seen in 46.7% (7/15) of the AIS cases. In 14 of the 15 cases of AIS (93.3%), the tumor was adjacent to the transitional zone, within 3 mm of the SCJ, and in the other case (6.7%), the tumor was between 0 and 5 mm away from the SCJ. In all subjects, cone height was 8–18 mm (mean 13.1 mm). None of the 15 patients showed any recurrence of AIS during follow up ranging from 15 to 75 months (43.1 months on average).

Conclusions: Women with AIS who want to preserve their fecundity might be treated with laser conization alone.
Sensitivity and specificity of mean corpuscular volume testing for screening for α‐thalassemia‐1 and β‐thalassemia traits
Authors: Sirichotiyakul Supatra , Maneerat Jatuchai , Sa‐nguansermsri Torpong , Dhananjayanonda Pisawat , Tongsong Theera
Published: May 2005

Aim: To evaluate the sensitivity, specificity, positive predictive value and negative predictive value of mean corpuscular volume (MCV) testing for screening for both α‐thalassemia‐1 and β‐thalassemia traits.

Methods: A diagnostic test was conducted on 439 pregnant women attending the antenatal care (ANC) clinic at Maharaj Nakorn Chiang Mai Hospital between April 2002 and July 2002. Blood samples were collected from the pregnant women after they were counseled and gave informed consent. The MCV was measured in all samples using an automated hematology analyzer. The hemoglobin (HbA2) level and polymerase chain reaction (PCR) were measured in all cases to test for the β‐thalassemia trait and the α‐thalassemia‐1 gene (South‐East Asian [SEA] type), respectively. The data were collected and analyzed for sensitivity, specificity, positive predictive value and negative predictive value for evaluating the efficacy of MCV testing for screening for both α‐thalassemia‐1 and β‐thalassemia traits.

Results: Positive MCV tests (≤80 fl) showed a sensitivity of 92.9% and specificity of 83.9% in screening for α‐thalassemia‐1 and β‐thalassemia traits, respectively. The positive predictive value and negative predictive value were 37.9% and 99.1%, respectively.

Conclusion: MCV evaluation is a useful tool for screening for α‐thalassemia‐1 and β‐thalassemia traits during pregnancy because of its simplicity, low cost and high sensitivity.
No association of polymorphisms in the glutathione S‐transferase genes with pre‐eclampsia, eclampsia and HELLP syndrome in a Turkish population
Authors: Cetin Meral , Pinarbasi Ergun , Percin Ferda E. , Akgün Egemen , Percin Sibel , Pinarbasi Hatice , Gurlek Fatma , Cetin Ali
Published: May 2005

Aim: There is substantial evidence that genetic factors play a role in pre‐eclampsia. The aim of this study was to determine whether genetic variability in the encoding of genes for glutathione S‐transferase M1 (GSTM1) and glutathione S‐transferase T1 (GSTT1) contributes to individual differences in susceptibility to pre‐eclampsia, eclampsia, or hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome).

Methods: A total of 221 women with pre‐eclampsia, eclampsia and HELLP syndrome and 147 healthy female controls were genotyped for GSTM1 and GSTT1 polymorphisms by polymerase chain reaction (PCR). Statistical evaluation of differences in polymorphic rates was carried out using χ2 analysis.

Results: This study included 140 pre‐eclamptic, 33 eclamptic and 48 HELLP syndrome cases and 147 healthy controls. The frequencies for the GSTM1 null genotype were 58%, 45%, and 60% for pre‐eclampsia, eclampsia, and HELLP syndrome, respectively, and in controls it was 55%. The distribution of the GSTT1 null genotype was  22%,  21%,  and  27%  for  pre‐eclampsia,  eclampsia,  and  HELLP  syndrome,  respectively,  and  in  controls  it was 22%. There was no significant association between GSTM1 and GSTT1 polymorphisms and pre‐eclampsia, eclampsia, and HELLP syndrome.

Conclusion: Our data do not support a role for polymorphisms of the GSTM1 and GSTT1 genes in the pathogenesis of pre‐eclampsia, eclampsia and HELLP syndrome.
Leiomyoma of the ovary presenting with Meigs’ syndrome
Authors: Kurai Miyuki , Shiozawa Tanri , Noguchi Hiroshi , Konishi Ikuo
Published: May 2005

Ovarian leiomyoma is a rare tumor. Ovarian leiomyoma accompanied with Meigs’ syndrome is extremely rare. We report a case of ovarian leiomyoma presenting with Meigs’ syndrome, which was first noted as dyspnea in a 79‐year‐old woman. A whole‐body examination revealed a solid mass of the ovary, accumulation of ascites and pleural effusion, and elevated serum carbohydrate antigen 125. Abdominal hysterectomy and salpingo‐oophorectomy were carried out. After the surgery, ascites and pleural effusion disappeared. The pathological diagnosis of the removed tumor was leiomyoma of the left ovary. The patient has been healthy for 24 months after the surgery, with no signs of recurrence. We also review the literature on this disease and the clinicopathologic characteristics of the current case are discussed.
Structural Learning with Time-Varying Components: Tracking the Cross-Section of Financial Time Series
Authors: Talih Makram , Hengartner Nicolas
Published: May 2005

When modelling multivariate financial data, the problem of structural learning is compounded by the fact that the covariance structure changes with time. Previous work has focused on modelling those changes by using multivariate stochastic volatility models. We present an alternative to these models that focuses instead on the latent graphical structure that is related to the precision matrix. We develop a graphical model for sequences of Gaussian random vectors when changes in the underlying graph occur at random times, and a new block of data is created with the addition or deletion of an edge. We show how a Bayesian hierarchical model incorporates both the uncertainty about that graph and the time variation thereof.
Small Confidence Sets for the Mean of a Spherically Symmetric Distribution
Authors: Samworth Richard
Published: May 2005

Suppose that X has a k-variate spherically symmetric distribution with mean vector θ and identity covariance matrix. We present two spherical confidence sets for θ, both centred at a positive part Stein estimator TS+(X). In the first, we obtain the radius by approximating the upper α-point of the sampling distribution of ‖TS+(X)−θ‖2 by the first two non-zero terms of its Taylor series about the origin. We can analyse some of the properties of this confidence set and see that it performs well in terms of coverage probability, volume and conditional behaviour. In the second method, we find the radius by using a parametric bootstrap procedure. Here, even greater improvement in terms of volume over the usual confidence set is possible, at the expense of having a less explicit radius function. A real data example is provided, and extensions to the unknown covariance matrix and elliptically symmetric cases are discussed.
Properties of Bagged Nearest Neighbour Classifiers
Authors: Hall Peter , Samworth Richard J.
Published: May 2005

It is shown that bagging, a computationally intensive method, asymptotically improves the performance of nearest neighbour classifiers provided that the resample size is less than 69% of the actual sample size, in the case of with-replacement bagging, or less than 50% of the sample size, for without-replacement bagging. However, for larger sampling fractions there is no asymptotic difference between the risk of the regular nearest neighbour classifier and its bagged version. In particular, neither achieves the large sample performance of the Bayes classifier. In contrast, when the sampling fractions converge to 0, but the resample sizes diverge to ∞, the bagged classifier converges to the optimal Bayes rule and its risk converges to the risk of the latter. These results are most readily seen when the two populations have well-defined densities, but they may also be derived in other cases, where densities exist in only a relative sense. Cross-validation can be used effectively to choose the sampling fraction. Numerical calculation is used to illustrate these theoretical properties.
Self-Weighted Least Absolute Deviation Estimation for Infinite Variance Autoregressive Models
Authors: Ling Shiqing
Published: May 2005

How to undertake statistical inference for infinite variance autoregressive models has been a long-standing open problem. To solve this problem, we propose a self-weighted least absolute deviation estimator and show that this estimator is asymptotically normal if the density of errors and its derivative are uniformly bounded. Furthermore, a Wald test statistic is developed for the linear restriction on the parameters, and it is shown to have non-trivial local power. Simulation experiments are carried out to assess the performance of the theory and method in finite samples and a real data example is given. The results are entirely different from other published results and should provide new insights for future research on heavy-tailed time series.
Statistical Inference for Discretely Observed Markov Jump Processes
Authors: Bladt Mogens , Sørensen Michael
Published: May 2005

Likelihood inference for discretely observed Markov jump processes with finite state space is investigated. The existence and uniqueness of the maximum likelihood estimator of the intensity matrix are investigated. This topic is closely related to the imbedding problem for Markov chains. It is demonstrated that the maximum likelihood estimator can be found either by the EM algorithm or by a Markov chain Monte Carlo procedure. When the maximum likelihood estimator does not exist, an estimator can be obtained by using a penalized likelihood function or by the Markov chain Monte Carlo procedure with a suitable prior. The methodology and its implementation are illustrated by examples and simulation studies.
Variance of the Number of False Discoveries
Authors: Owen Art B.
Published: May 2005

In high throughput genomic work, a very large number d of hypotheses are tested based on n≪d data samples. The large number of tests necessitates an adjustment for false discoveries in which a true null hypothesis was rejected. The expected number of false discoveries is easy to obtain. Dependences between the hypothesis tests greatly affect the variance of the number of false discoveries. Assuming that the tests are independent gives an inadequate variance formula. The paper presents a variance formula that takes account of the correlations between test statistics. That formula involves O(d2) correlations, and so a naïve implementation has cost O(nd2). A method based on sampling pairs of tests allows the variance to be approximated at a cost that is independent of d.
Calibrated Imputation in Surveys Under a Quasi-Model-Assisted Approach
Authors: Beaumont Jean-François
Published: May 2005

We propose to use calibrated imputation to compensate for missing values. This technique consists of finding final imputed values that are as close as possible to preliminary imputed values and are calibrated to satisfy constraints. Preliminary imputed values, potentially justified by an imputation model, are obtained through deterministic single imputation. Using appropriate constraints, the resulting imputed estimator is asymptotically unbiased for estimation of linear population parameters such as domain totals. A quasi-model-assisted approach is considered in the sense that inferences do not depend on the validity of an imputation model and are made with respect to the sampling design and a non-response model. An imputation model may still be used to generate imputed values and thus to improve the efficiency of the imputed estimator. This approach has the characteristic of handling naturally the situation where more than one imputation method is used owing to missing values in the variables that are used to obtain imputed values. We use the Taylor linearization technique to obtain a variance estimator under a general non-response model. For the logistic non-response model, we show that ignoring the effect of estimating the non-response model parameters leads to overestimating the variance of the imputed estimator. In practice, the overestimation is expected to be moderate or even negligible, as shown in a simulation study.
PHILANTHROPY AND ENTERPRISE IN THE BRITISH CREDIT UNION MOVEMENT
Authors: Jones Paul A.
Published: May 2005

Through the 1990s hundreds of credit unions were established to serve indebted communities throughout Britain. These volunteer‐run financial co‐operatives did not meet growth expectations because of restrictive legislation, inadequate development models and well‐intentioned but unproductive state intervention. British credit unions are more successful when they develop as market‐oriented social enterprises able to build effective partnerships with banks, government and the private sector to serve low‐income communities.
IS THERE A CONFLICT BETWEEN COMMERCIAL GAIN AND CONCERN FOR THE POOR? EVIDENCE FROM PRIVATE SCHOOLS FOR THE POOR IN INDIA AND NIGERIA
Authors: Tooley James , Dixon Pauline
Published: May 2005

In many developing countries, private unaided schools are serving the poor in large numbers. Some commentators view their presence as undesirable ‐ in particular assuming that there is a conflict between‘commercial gain’ and ‘concern for the poor’. We show one way in which there is no conflict ‐ the private unaided schools offer free or concessionary places to the poorest of the poor. Using data from a random sample of schools in Hyderabad, India, and a smaller sample in Makoko, Nigeria, we show that such places range from 10–20% of all places offered.
INTERNATIONAL TRADE AND GLOBAL STABILITY1
Authors: O'Driscoll Gerald P. , Cooper Sara F.
Published: May 2005

Trade liberalisation has played a critical role in advancing peace and prosperity. Differences on agriculture have been the major impediment to a future multilateral trade round. The recent agreement on agriculture at the WTO meetings in Geneva may signal a breakthrough in that sector. This article analyses the benefits of recent trade agreements and examines the prospects for future ones. It also presents an alternative framework for advancing trade, the Global Free Trade Association.
CHRISTIANITY, THE MARKET ECONOMY AND THE LIMITS TO HUMAN KNOWLEDGE
Authors: Booth Philip
Published: May 2005

At one time, the prevailing view amongst Christian clergy in Britain would have been sympathetic towards the spontaneous order of the market economy and not sympathetic towards socialism. The spontaneous order, would, of course, have included the rich tapestry of philanthropic organisations and mutual societies that used to provide welfare for the poor. The clergy today are not generally sympathetic towards the market order. An understanding of Austrian ideas takes us to the view that, at the very least, socialist rationalism is the common enemy of Christians and those who support a free market order.
POVERTY, INSTITUTIONS AND ECONOMICS: HERNANDO DE SOTO ON PROPERTY RIGHTS AND ECONOMIC DEVELOPMENT1
Authors: Ricketts Martin
Published: May 2005

Hernando de Soto's analysis of the high cost of establishing, protecting and trading in property rights in his home country of Peru and other developing nations demonstrates the centrality of institutions to economic analysis and outcomes. The effective denial of property rights to hundreds of thousands of poor people means that their economic potential and that of their countries is largely untapped. De Soto's Peruvian think‐tank, the Institute for Liberty and Democracy, has worked for 20 years towards the implementation of reforms to clear property titles and reduce the excessive regulation that stifles developing world entrepreneurship.
LICENCE VALUES IN TAXI MARKETS
Authors: Koehler Benedikt
Published: May 2005

Wherever taxi regulators cap the number of taxis, operating licences acquire economic value. In the UK, the Office of Fair Trading recommended legislative repeal of quantity caps, but the status quo continues. This article argues that licence values send an important signal to taxi regulators.
Colour Vision in Migraine: Selective Deficits for S-Cone Discriminations
Authors: Shepherd AJ
Published: May 2005

Three studies are reported that explore colour perception in migraine. In each, sensitivity for colours detected selectively by the S-cones and the L- and M-cones was assessed separately. The first study assessed the discrimination of small colour differences using the Farnsworth-Munsell 100-hue test. The second assessed threshold detection for purple, yellow, red and green targets on five equiluminant background colours. The third examined supra-threshold colour scaling using two colour series, purple-yellow and red-green. Each study indicated that differences in colour perception between migraine and control groups were restricted to colours detected by the S-cones, there were no differences in performance for colours detected by the L- and M-cones. The results are discussed in terms of possible pathologies in the early visual pathways.
Melatonin, the Pineal Gland and their Implications for Headache Disorders
Authors: Peres MFP
Published: May 2005

There is now evidence that melatonin may have a role in the biological regulation of circadian rhythms, sleep, mood, and ageing. Altered melatonin levels in cluster headache and migraine have been documented. Melatonin mechanisms are related to headache pathophysiology in many ways, including its anti-inflammatory effect, toxic free radical scavenging, reduction of proinflammatory cytokine up-regulation, nitric oxide synthase activity and dopamine release inhibition, membrane stabilization, GABA and opioid analgesia potentiation, glutamate neurotoxicity protection, neurovascular regulation, serotonin modulation, and the similarity of chemical structure to that of indomethacin. Treatment of headache disorders with melatonin and other chronobiotic agents is promising. A doubleblind, placebo-controlled trial shows melatonin is effective in cluster headache prevention, other studies also show benefit in other disorders. Melatonin plays an important role in headache disorders, offering new avenues for studying their pathophysiology and treatment.
The information needs and information‐seeking behaviours of home‐care workers and clients receiving home care
Authors: Cooper Janet , Urquhart Christine
Published: May 2005

Aims and objectives:  Discusses findings from doctoral research on the information behaviour of home‐care workers and their clients. The paper focuses on the findings, which have implications for health library and information services.

Sample and methods:  The qualitative research methods included participant observation in the homes of clients (n = 7), over a period of 18 months, in a city in the UK, complemented by in‐depth interviews of home‐care staff (n = 47).

Results:  Home‐care staff perceived requests for information on a variety of topics as an indivisible part of their caring role. Clients asked for more information than they had in the past, and home‐care workers were expected to respond to a wide variety of enquiries about health, welfare, leisure and domestic concerns. Clients trusted their advice as much as they might have trusted members of the family. Home‐care workers from an agency used a variety of resources at the agency office to help them, such as leaflets on welfare benefits, and health conditions. Few had used NHS Direct, and library use (by a third of the home‐care workers) was generally associated with course work or training. Some family members and home‐care staff used self‐help groups, but the research found that family members were sometimes reticent to ask advice on sensitive issues in self‐help groups. Home‐care workers learnt from each other and shared experience.

Conclusions:  Libraries and information services need to target provision of formal information carefully, as it is advice and counsel that is required in the home‐care setting.
Chasing the Sun: a virtual reference service between SAHSLC (SA) and SWICE (UK)
Authors: Rockliff Sue , Peterson Mary , Martin Kath , Curtis Dorothy
Published: May 2005

Aim:  In 2002, a discussion in the United Kingdom (UK) between South‐west Information for Clinical Effectiveness (SWICE) librarians and a member of the South Australian Department of Human Services Libraries’ Consortium (SAHSLC) raised the possibility of developing an after‐hours virtual reference service between the two consortium groups. The aim of the service is to put medical practitioners in contact with a librarian when urgent help is required in finding clinical medical information after hours.

Methods:  A trial project has begun and has been given the name ‘Chasing the Sun’. The service will make use of time‐zone differences between the UK and Australia, so that librarians at work in another country will be able to answer urgent patient‐related queries that cannot wait until normal office hours.

Results:  This paper looks at the development of ‘Chasing the Sun’ from initial concept, funding proposal and trial project stage to implementation. It includes details of the groundwork, software evaluation, trials, outcomes, cost and benefits, future directions and potential problems yet to be experienced or overcome.

Conclusion:  This service is the first of its kind between health libraries in the world and offers potential for future worldwide expansion.
Impacts of Managed Care Patient Protection Laws on Health Services Utilization and Patient Satisfaction with Care
Authors: Sloan Frank A. , Rattliff John R. , Hall Mark A.
Published: May 2005

Objective. To assess effects of patient protection laws implemented by the vast majority of states during the 1990s on the public's satisfaction and trust relating to health care, and on key utilization measures.

Data Sources/Study Setting. Measures of individuals' health care utilization and satisfaction, and control variables, came from three waves of the Community Tracking Study (CTS) Household Surveys conducted in 1996–1997, 1998–1999, and 2000–2001. The CTS was conducted in 60 randomly selected communities, throughout the U.S. In addition, a supplemental national sample of households from CTS was also included, resulting in a combined sample with cases from 48 states and the District of Columbia. After applying exclusion restrictions, the analysis sample was 149,688 adults.

Study Design. Using a fixed‐effects methodology, we assessed the influence of patient protection laws on satisfaction with care and utilization of services for the entire sample and for subsamples of persons in poor health, with low income, and who were enrolled in HMOs.

Data Collection/Extraction Methods. One of the authors (Hall) compiled relevant laws in all U.S. states through 2001 from primary legal sources, checking for accuracy by conducting independent research on statutory changes and by asking three to five regulators in each state to verify that the information was correct.

Principal Findings. Overall, patient protection laws had little or no effect on either trust, satisfaction with care, or utilization. Significance was found postenactment of a state patient protection law only for emergency room visits in the general sample, and only for physician trust in the low‐income sample. Because of the number of possible associations examined, occasional findings of significance could occur by chance.

Conclusions.

Enactment of managed care patient protection laws did not generally increase utilization of health services or improve patient satisfaction with care.
The Effect of Medicaid Payment Generosity on Access and Use among Beneficiaries
Authors: Shen Yu‐Chu , Zuckerman Stephen
Published: May 2005

Objective. This study examines the effects of Medicaid payment generosity on access and care for adult and child Medicaid beneficiaries.

Data Source. Three years of the National Surveys of America's Families (1997, 1999, 2002) are linked to the Urban Institute Medicaid capitation rate surveys, the Area Resource File, and the American Hospital Association survey files.

Study Design. In order to identify the effect of payment generosity apart from unmeasured differences across areas, we compare the experiences of Medicaid beneficiaries with groups that should not be affected by Medicaid payment policies. To assure that these groups are comparable to Medicaid beneficiaries, we reweight the data using propensity score methods. We use a difference‐in‐differences model to assess the effects of Medicaid payment generosity on four categories of access and use measures (continuity of care, preventive care, visits, and perceptions of provider communication and quality of care).

Principal Findings. Higher payments increase the probability of having a usual source of care and the probability of having at least one visit to a doctor and other health professional for Medicaid adults, and produce more positive assessments of the health care received by adults and children. However, payment generosity has no effect on the other measures that we examined, such as the probability of receiving preventive care or the probability of having unmet needs.

Conclusions. Higher payment rates can improve some aspects of access and use for Medicaid beneficiaries, but the effects are not dramatic.