bluuebunny/crossref_metadata_2025 huggingface dataset:
Proactive versus reactive business ethics performance: a conceptual framework of profile analysis and case illustrations
Authors: Svensson Goran , Wood Greg
Published: May 2004

The topic of this paper focuses on proactive versus reactive business ethics performance in the marketplace. The internal perception of a corporation and the external perception of the same corporation are used as generic determinants of business ethics performance. In turn, they are underpinned by evolutionary and contextual issues in the marketplace. The authors provide a generic conceptual framework of proactive and reactive business ethics performance. Case illustrations underpin the positives and negatives of proactive and reactive business ethics in the marketplace. A profile analysis process of proactive and reactive business ethics performance is also outlined. The gap between the internal and external perceptions of a corporation’s actions becomes crucial to achieve successful business ethics performance in the marketplace. Therefore, a corporation’s current business ethics performance should always be regarded as an on‐the‐spot‐account that is either proactive or reactive. An important insight of this research is that business ethics performance requires the ongoing re‐connection with reality by corporations.
Genetic Models with Reduced Penetrance Related to the Y Chromosome
Authors: Darling R. W. R. , Holt Tim
Published: May 2004

Summary. Classical statistical genetics models of a quantitative trait depending on an autosomal gene indicate that father‐to‐daughter and mother‐to‐son correlations should be the same. If phenotypes are not sex‐dependent, father‐to‐son and mother‐to‐daughter correlations also share this common value. On the other hand, if the gene is sex‐linked, then the father‐to‐son correlation is zero. Such models do not explain genetic variation in pulmonary artery pressure (PAP) of cattle—important because cattle with high PAP are known to develop brisket disease, pulmonary heart disease, and congestive heart failure when taken to high altitudes. Data on 966 calves at a ranch in Colorado showed positive correlation (0.2) between sire PAP and male calf PAP but slightly negative correlation (–0.01) between sire PAP and female calf PAP; the dam‐to‐male calf and dam‐to‐female calf correlations are both about 0.1. The model presented here postulates an autosomal gene with reduced penetrance (i.e., the trait may remain at a normal level even when the genotype suggests abnormality) and that, in males, the rate of penetrance is related to an abnormality in the Y chromosome and is therefore passed on from father to son. Then under plausible selective breeding assumptions, the pairwise correlation between fathers and daughters can become zero or negative. Explicit formulas are computed for the model covariances, and numerical computations indicate that plausible parameter values can be chosen for the model.
Bias‐Corrected Confidence Intervals for the Concentration Parameter in a Dilution Assay
Authors: Wang Jinping , Basu Sabyasachi
Published: May 2004

Summary. Interval estimates of the concentration of target entities from a serial dilution assay are usually based on the maximum likelihood estimator. The distribution of the maximum likelihood estimator is skewed to the right and is positively biased. This bias results in interval estimates that either provide inadequate coverage relative to the nominal level or yield excessively long intervals. Confidence intervals based on both log transformation and bias reduction are proposed and are shown through simulations to provide appropriate coverage with shorter widths than the commonly used intervals in a variety of designs. An application to feline AIDS research, which motivated this work, is also presented.
Comparing the Performances of Diggle's Tests of Spatial Randomness for Small Samples with and without Edge‐Effect Correction: Application to Ecological Data
Authors: Gignoux Jacques , Duby Camille , Barot Sébastian
Published: May 2004

Summary.Diggle's tests of spatial randomness based on empirical distributions of interpoint distances can be performed with and without edge‐effect correction. We present here numerical results illustrating that tests without the edge‐effect correction proposed by Diggle (1979,Biometrics35, 87–101) have a higher power for small sample sizes than those with correction. Ignoring the correction enables detection of departure from spatial randomness with smaller samples (down to 10 points vs. 30 points for the tests with correction). These results are confirmed by an example with ecological data consisting of maps of two species of trees in a West African savanna. Tree numbers per species per map were often less than 20. For one of the species, for which maps strongly suggest an aggregated pattern, tests without edge‐effect correction enabled rejection of the null hypothesis on three plots out of five vs. on only one for the tests with correction.
A Random Effects Model for Multivariate Failure Time Data from Multicenter Clinical Trials
Authors: Cai Jianwen , Sen Pranab K. , Zhou Haibo
Published: May 2004

Summary.A random effects model for analyzing multivariate failure time data is proposed. The work is motivated by the need for assessing the mean treatment effect in a multicenter clinical trial study, assuming that the centers are a random sample from an underlying population. An estimating equation for the mean hazard ratio parameter is proposed. The proposed estimator is shown to be consistent and asymptotically normally distributed. A variance estimator, based on large sample theory, is proposed. Simulation results indicate that the proposed estimator performs well in finite samples. The proposed variance estimator effectively corrects the bias of the naive variance estimator, which assumes independence of individuals within a group. The methodology is illustrated with a clinical trial data set from the Studies of Left Ventricular Dysfunction. This shows that the variability of the treatment effect is higher than found by means of simpler models.
Statistical Inference for Self‐Designing Clinical Trials with a One‐Sided Hypothesis
Authors: Shen Yu , Fisher Lloyd
Published: May 2004

Summary. In the process of monitoring clinical trials, it seems appealing to use the interim findings to determine whether the sample size originally planned will provide adequate power when the alternative hypothesis is true, and to adjust the sample size if necessary. In the present paper, we propose a flexible sequential monitoring method following the work of Fisher (1998), in which the maximum sample size does not have to be specified in advance. The final test statistic is constructed based on a weighted average of the sequentially collected data, where the weight function at each stage is determined by the observed data prior to that stage. Such a weight function is used to maintain the integrity of the variance of the final test statistic so that the overall type I error rate is preserved. Moreover, the weight function plays an implicit role in termination of a trial when a treatment difference exists. Finally, the design allows the trial to be stopped early when the efficacy result is sufficiently negative. Simulation studies confirm the performance of the method.
Survival and Hazard Functions for Progressive Diseases Using Saddlepoint Approximations
Authors: Huzurbazar S. , Huzurbazar Aparna V.
Published: May 2004

Summary.Saddlepoint approximations for the computation of survival and hazard functions are introduced in the context of parametric survival analysis. Although these approximations are computationally fast, accurate, and relatively straightforward to implement, their use in survival analysis has been lacking. We approximate survival functions using the Lugannani and Rice Saddlepoint approximation to the distribution function or by numerically integrating the saddlepoint density approximation. The hazard function is approximated using the saddlepoint density and distribution functions. The approximations are especially useful for consideration of survival and hazard functions for waiting times in complicated models. Examples include total or partial waiting times for a disease that progresses through various stages (convolutions of distributions).
Robustness of Group Testing in the Estimation of Proportions
Authors: Hung M. , Swallow William H.
Published: May 2004

Summary. In binomial group testing, unlike one‐at‐a‐time testing, the test unit consists of a group of individuals, and each group is declared to be defective or nondefective. A defective group is one that is presumed to include one or more defective (e.g., infected, positive) individuals and a nondefective group to contain only nondefective individuals. The usual binomial model considers the individuals being grouped as independent and identically distributed Bernoulli random variables. Under the binomial model and presuming that groups are tested and classified without error, it has been shown that, when the proportion of defective individuals is low, group testing is often preferable to individual testing for identifying infected individuals and for estimating proportions of defectives. We discuss the robustness of group testing for estimating proportions when the underlying assumptions of (i) no testing errors and (ii) independent individuals are violated. To evaluate the effect of these model violations, two dilution‐effect models and a serial correlation model are considered. Group testing proved to be quite robust to serial correlation. In the presence of a dilution effect, smaller group sizes should be used, but most of the benefits of group testing can still be realized.
A Hierarchical Bayesian Model for Combining Multiple 2 × 2 Tables Using Conditional Likelihoods
Authors: Liao J. G.
Published: May 2004

Summary. This paper introduces a hierarchical Bayesian model for combining multiple 2×2 tables that allows the flexibility of different odds ratio estimates for different tables and at the same time allows the tables to borrow information from each other. The proposed model, however, is different from a full Bayesian model in that the nuisance parameters are eliminated by conditioning instead of integration. The motivation is a more robust model and a faster and more stable Gibbs algorithm. We work out a Gibbs scheme using the adaptive rejection sampling for log concave density and an algorithm for the mean and variance of the noncentral hypergeometric distribution. The model is applied to a multicenter ulcer clinical trial.
A Note on an Exact Test and Confidence Interval for Competition and Overlap Effects
Authors: Shukla G. K. , Subrahmanyam G. S. V.
Published: May 2004

Summary.A method has been proposed that gives an exact test and confidence interval for the coefficient of overlap and competition effects. The method is based on Tukey's statistic of nonadditivity. The method is very simple to adopt and can be implemented by regression analysis and analysis of variance programmes in some important cases.
Power and Sample Size for Testing Homogeneity of Relative Risks in Prospective Studies
Authors: Nam Jun‐Mo
Published: May 2004

Summary. Power and sample‐size formulas for testing the homogeneity of relative risks using the score method are presented. The homogeneity score test (Gart, 1985, Biometrika72, 673–677) is formally equivalent to the Pearson chi‐square test, although they look different. Results of this paper may be useful in assessing the validity of the model of a common relative risk before combining several 2 × 2 tables or in designing a prospective study for detecting heterogeneity of relative risks.
Optimum Experimental Designs for Multinomial Logistic Models
Authors: Zocchi Silvio S. , Atkinson Anthony C.
Published: May 2004

Summary.Multinomial responses frequently occur in dose level experiments. For example, in a study of the influence of gamma radiation on the emergence of house flies (Musca domesticaL., 1758), three disjoint outcomes occurred: death before the pupae opened, death during emergence, and life after emergence. Although the flies are easy to breed, this sort of bioassay is, in general, very expensive since it requires the use of a gamma radiation source. Experiments therefore need to be designed to involve the minimum number of different doses. Here the theory of optimum experimental design is applied to provide efficient experiments to estimate the parameters of those multinomial logistic models that are a special case of the multivariate logistic models of Glonek and McCullagh (1995,Journal of the Royal Statistical Society, Series B57, 533–546). The purpose is to reduce the overall experimental cost. The general equivalence theorem (Fedorov, 1972,Theory of Optimal Experiments) is adapted to this class of models, providing an effective method of generating and checking the optimality of designs. One example on flies demonstrates the method, which can be easily implemented.
Adjusted Regression Trend Test for a Multicenter Clinical Trial
Authors: Quan Hui , Capizzi Thomas
Published: May 2004

Summary. Studies using a series of increasing doses of a compound, including a zero dose control, are often conducted to study the effect of the compound on the response of interest. For a one‐way design, Tukey et al. {1985, Biometrics41, 295–301) suggested assessing trend by examining the slopes of regression lines under arithmetic, ordinal, and arithmetic‐logarithmic dose scalings. They reported the smallest p‐value for the three significance tests on the three slopes for safety assessments. Capizzi et al. (1992, Biometrical Journal34, 275–289) suggested an adjusted trend test, which adjusts the p‐value using a trivariate t‐distribution, the joint distribution of the three slope estimators. In this paper, we propose an adjusted regression trend test suitable for two‐way designs, particularly for multicenter clinical trials. In a step‐down fashion, the proposed trend test can be applied to a multicenter clinical trial to compare each dose with the control. This sequential procedure is a closed testing procedure for a trend alternative. Therefore, it adjusts p‐values and maintains experimentwise error rate. Simulation results show that the step‐down trend test is overall more powerful than a step‐down least significant difference test.
Analysis of Multistage Pooling Studies of Biological Specimens for Estimating Disease Incidence and Prevalence
Authors: Brookmeyer Ron
Published: May 2004

Summary. The testing of pooled samples of biological specimens for the purpose of estimating disease prevalence may be more cost effective than testing individual samples, particularly if the prevalence of disease is low. Multistage pooling studies involve testing pools and then sequentially subdividing and testing the positive pools. A simple estimator of disease prevalence and its variance are derived for general multistage pooling studies and are shown t o be natural generalizations of Thompson's (1962) original estimators for single‐stage pooling studies. The reduction in variance associated with each additional stage is calibrated. The results are extended to estimating disease incidence rates. The methods are used to estimate HIV incidence rates from a prevalence study of early HIV infection using a PCR assay for HIV RNA.
Comparison of Several Independent Population Means When Their Samples Contain Log‐Normal and Possibly Zero Observations
Authors: Xiao‐Hua Zhou , Tu Wanzhu
Published: May 2004

Summary.In this paper, we consider the problem of testing the mean equality of several independent populations that contain log‐normal and possibly zero observations. We first showed that the currently used methods in statistical practice, including the nonparametric Kruskal–Wallis test, the standard ANOVAF‐test and its two modified versions, the Welch test and the Brown–Forsythe test, could have poor Type I error control. Then we propose a likelihood ratio test that is shown to have much better Type I error control than the existing methods. Finally, we analyze two real data sets that motivated our study using the proposed test.
Modelling Ties in the Sign Test
Authors: Rayner J. C. W. , Best D. J.
Published: May 2004

Summary. If ties occur in the sign test, the procedure recommended by Coakley and Heise (1996, Biometrics52, 1242–1251) is the asymptotic uniformly most powerful nonrandomised test due to Putter (1955, Annals of Mathematical Statistics26, 368–386). It may be shown that this is a consequence of how the probability of a tie is modelled. Other models with different optimal procedures can be constructed.
Susceptibility of spatial and verbal working memory to demands of the central executive1
Authors: KONDO HIROHITO , OSAKA NAOYUKI
Published: May 2004

Abstract:  We used a dual‐task paradigm to examine the degree to which domain‐specific spatial and verbal subsystems depend on the domain‐general central executive. Forty participants were asked to retain spatial or verbal information while performing a concurrent secondary task related to simple arithmetic. The secondary tasks consisted of three cognitive processes: single‐digit addition, a digit‐carrying operation, and digit reading. The single‐digit addition and carry operation include central executive functioning, while digit reading relies solely on the phonological loop. The single‐digit addition caused a performance decrement on the spatial working memory task, while the digit reading impaired performance on the verbal working memory task. The carry operation interfered with recall accuracy on both working memory tasks. The spatial working memory task was significantly correlated with the verbal working memory task only when the secondary task was more demanding on the central executive. Our results suggest that spatial working memory rather than verbal working memory is susceptible to failure of central executive functioning and that the central executive plays an important role in regulating the cognitive demands of different domains.
Repetition effect in visual recognition of letters1
Authors: KUWANA TOSHINORI
Published: May 2004

Abstract:  This study examined the influence of the repetitive presentation of a letter on the recognition of two letters. In two experiments4, two letters, which were either identical or not, were presented successively for a short duration at different spatial locations, and the subjects were required to identify them. In Experiment 1, the presentation time of the first letter was varied, whereas that of the second letter was constant. The results revealed that a reduced performance in identifying a second letter was observed in the case that the first letter, which was identical to the second letter, could be identified correctly. Experiment 2 examined whether or not this reduction was due to the identity of the visual shape of two letters. The first letter was presented either in the usual vertical orientation or rotated orientation by 180 degrees and the second letter was constantly presented in the usual orientation. The results revealed that a reduced performance in identifying a repeated letter was observed, regardless of the orientation of the first letter. The findings from the two experiments suggested that the identity of the information in memory was a main cause of the interference effect by repetition.
Young children's change in strategies of size comparison: Effects of task repetition and strategy evaluation1
Authors: YUZAWA MIKI , YUZAWA MASAMICHI
Published: May 2004

Abstract:  This study examined how young children change their strategies for size comparison. Twenty‐two 5 and 6‐year‐old children were asked to compare the sizes of geometric figures and their strategies were observed once a week over three weeks. Half of the children were also asked to evaluate presented strategies for comparing geometric figures. It was found that over three weeks not only children who evaluated the strategies but also children who did not increased correct responses, the strategy of placing one figure on another, and the strategy of adjusting two figures by two dimensions. Although more children became aware of the effectiveness of those strategies, there was no relationship between the evaluation and use of strategies.
Significance of atypia in conventional Papanicolaou smears and liquid‐based cytology: a follow‐up study
Authors: Schledermann D. , Ejersbo D. , Hoelund B.
Published: May 2004

The diagnosis of atypical squamous epithelial cells, borderline nuclear changes, is associated with some controversy, as it encompasses benign, reactive, as well as possible neoplastic conditions. The aim of this study was to evaluate the follow‐up diagnoses of cytological atypia in conventional Papanicolaou smears (CP) and liquid‐based samples by the ThinPrep® Pap TestTM (TP). A total of 1607 CP smears from 1 January 2000 to 31 December 2000 and 798 TP samples from 1 January 2002 to 31 December 2002 diagnosed as atypia were included. The results show that the detection rate of atypia in cervical cytological samples was reduced by 41.3% (P < 0.001) in TP compared with CP. Cytological and histological follow‐up data showed the presence of neoplastic lesions in 34.7% of patients screened by TP versus 22.3% of patients screened by CP, corresponding to a 55.6% increase in TP (P < 0.001). Follow‐up diagnosis of mild dysplasia was seen more than twice as often in TP than in CP (12.8% versus 5.0%, P < 0.001). The prevalence of moderate and severe dysplasia was significantly increased with 26.7% in TP compared with CP (21.9% versus 17.2%, P < 0.01). In conclusion, the ThinPrep® Pap TestTM yielded a significant decrease in atypia rates compared with the conventional Papanicolaou test. In subsequent follow‐up the percentage of neoplastic lesions was significantly increased in the ThinPrep® Pap TestTM samples.
Peritoneal washing cytology
Authors: Shield P.
Published: May 2004

Peritoneal washing cytology (PWC) is a useful indicator of ovarian surface involvement and peritoneal dissemination by ovarian tumours. It may identify subclinical peritoneal spread and thus provide valuable staging and prognostic information, particularly for non‐serous ovarian tumours. The role of PWC as a prognostic indicator for endometrial carcinoma is less clear, due in part to the questionable significance of identifying endometrial tumour cells in the peritoneum. Detection of metastatic carcinoma in PWC is based on the recognition of non‐mesothelial cell characteristics. However a number of conditions such as reactive mesothelial cells, endometriosis and endosalpingiosis may mimic this appearance. Cells from these conditions may have a similar presentation in PWC to that of serous borderline tumours and low‐grade serous carcinoma. The presence of cilia, lack of single atypical cells, prominent cytoplasmic vacuolation, marked nuclear atypia or two distinct cell populations are features favouring a benign process. Attention to these features along with close correlation with clinical history and the results of surgical pathology should help avoid errors. Additional assistance may be provided by the use of cell blocks and special stains.
MIB‐1 immunostaining on cytological samples: a protocol without antigen retrieval
Authors: Kirbiš I. Srebotnik , Fležar M. Strojan , Krašovec M. Us
Published: May 2004

The aim of the study was to evaluate the effect of fixation procedures on MIB‐1 immunostaining on microwave‐treated Papanicolaou‐stained slides and to establish protocol for MIB‐1 immunostaining on cytological samples without microwave pre‐treatment. Cytospins for immunostaining and nuclear suspension for DNA measurement were prepared from human breast cancer cell line (MCF‐7). Following fixation, the cytospins were either stained by Papanicolaou, stored in methanol or air‐dried. Antigen retrieval by microwave was used before MIB‐1 immunostaining only for Papanicolaou‐stained cytospins. Air‐dried cytospins and cytospins stored in methanol were immunostained without pre‐treatment. The percentage of MIB‐1 positive cells was compared with the S phase fraction of MCF‐7 cells calculated from DNA histograms. Variations in fixation procedures used before Papanicolaou staining had no influence on the percentage of MIB‐1 positive cells. The difference between the percentage of the MIB‐1‐positive cells on microwave‐treated Papanicolaou‐stained cytospins and on methanol‐fixed cytospins without microwave pre‐treatment was not significant. There was a strong correlation between the percentage of the MIB‐1‐positive cells and S phase fraction. Monoclonal antibody MIB‐1 recognized Ki‐67 antigen in Papanicolaou‐stained cytospins treated by microwave as well as in cytospins that were fixed and stored in methanol without microwave pre‐treatment.
Environmental benefit of different crayfish management strategies in Finland
Authors: Kirjavainen J. , Sipponen M.
Published: May 2004

In Finland, the nationwide strategy for crayfish management in inland waters was renewed in 2000. The main objective was to maintain and increase the stocks of indigenous noble crayfish, Astacus astacus L. In southern Finland many water courses are being chronically infected by crayfish plague. Consequently, the strategy attempts to restore the productivity of crayfish stocks by introducing plague‐resistant signal crayfish, Pacifastacus leniusculus Dana. Crayfish is the largest mobile macroinvertebrate in Finnish freshwater ecosystems and it plays an important role in the food web. It has also an economic value for recreational and commercial fishing. So far no physical impact of introducing signal crayfish or restocking noble crayfish to ecosystems has been observed. However, in the long term, signal crayfish is likely to eradicate native noble crayfish in waters where these species co‐exist.

Häme and Central Finland are two neighbouring provinces adhering to different crayfish management strategies. In Häme the results of noble crayfish stockings have been poor compared with the introduction of signal crayfish. Its recreational catch has increased rapidly, resulting in new employment opportunity. In Central Finland introduction of signal crayfish is forbidden and stocking of noble crayfish has been intensive. One goal is to maintain a gene pool resource of this species.
Survival of stocked Atlantic salmon and coarse fish and an evaluation of costs
Authors: Aprahamian M. W. , Barnard S. , Farooqi M. A.
Published: May 2004

The stocking of fish represents a major activity in current fisheries management practice. To maximise benefit to the environment in general and to fisheries in particular, optimal stocking strategies need to be developed. Examples from two studies, one involving Atlantic salmon, Salmo salar L., and the other involving three coarse fish species, are used to illustrate how such strategies might be developed. Atlantic salmon fed fry (age 0+) were stocked into eight streams in the North West of England at densities ranging from 1 to 4 m−2 over a period of up to 3 years to evaluate survival to the end of the first and second growing periods. Survival to the end of the first growing period (mean duration 108 days) varied between 1.2 and 41.3% with a mean of 20.45% and CV of 0.53. Survival from the end of the first growing period to the end of the second growing period (mean duration 384 days) ranged from 19.9 to 34.1% with a mean of 26.3% and a CV of 0.21. Hatchery‐reared roach, Rutilus rutilus (L.), chub, Leuciscus cephalus (L.) and dace, Leuciscus leuciscus (L.), were stocked into four rivers to determine the optimal age and season which would maximise survival over a 6‐month post‐stocking period. Post‐stocking persistence within the stocked reaches was generally low; the highest level of persistence was estimated at only 33.8%. However, most of the estimates of persistence were considerably lower and (in practical terms) approached zero in several instances. The analysis indicated that river‐specific factors are important in determining the success of stocking exercises. The survival estimates derived from these two studies were compared with other published estimates.
Management of lake fish populations and lake fisheries in Denmark: history and current status
Authors: Jacobsen L. , Berg S. , Skov C.
Published: May 2004

The development of lake fisheries in Denmark is described and the various management measures applied to lake fish populations reviewed. Over the last 100 years catch records revealed a peak in annual yield in the 1950s and 1960s, with a subsequent decrease in catches thereafter coinciding with increasing eutrophication of Danish lakes. In particular, catches of the most valuable fish, the eel, Anguilla anguilla (L.), have diminished. Lake fisheries are regulated by legislation to protect populations of lake fish of commercial and recreational interest and prevent overfishing. Management of lake fisheries includes stocking of, for example eel, trout, Salmo trutta L., and pike, Esox lucius L., and, previously, introduction of new species. Lately, management of the aquatic environment has favoured the desirable fish species, which are hampered in eutrophic lakes, with the exception of pikeperch, Sander lucioperca (L.), introduced in a number of Danish lakes. Biomanipulation has been carried out during the last decade to help rehabilitate lakes by either stocking of piscivorous fish or removing planktivorous fish.
Managed flooding as a tool for supporting natural fish reproduction in man‐made lentic water bodies
Authors: Jurajda P. , Ondračková M. , Reichard M.
Published: May 2004

In 2001, fish diversity and abundance were investigated in six man‐made borrow pits in the flood plain of the River Dyje (Danube basin). All borrow pits had uniform habitats without shelter, and with limited spawning and nursery areas. Spawning and nursery habitat conditions in three borrow pits were experimentally improved by managed flooding during spring and summer, while the other three borrow pits were not flooded. Adult (>1 year) fish were surveyed in spring and autumn by beach seining and 0+ fish were monitored monthly by dipnetting and fry beach seine nets. Flooded borrow pits had slightly higher adult species richness, considerably higher adult fish abundance and considerably higher 0+ fish species richness and abundance. The seasonal decline in 0+ fish abundance varied between flooded and non‐flooded borrow pits, with a faster decline in 0+ abundance at non‐flooded sites. Management implications for floodplain lentic water bodies are discussed.
How to link biomanipulation and sustainable fisheries management: a step‐by‐step guideline for lakes of the European temperate zone
Authors: Mehner T. , Arlinghaus R. , Berg S. , Dörner H. , Jacobsen L. , Kasprzak P. , Koschel R. , Schulze T. , Skov C. , Wolter C. , Wysujack K.
Published: May 2004

Biomanipulation, the reduction of planktivorous fish to enhance filter‐feeding zooplankton, has been used to rehabilitate eutrophied lakes. However, efficacy and long‐term success were dependent on nutrient load, lake morphometry and biomanipulation measures. The ongoing focus on sustainable use of aquatic resources offers the chance to perform lake rehabilitation using a combined strategy of nutrient load reduction and traditional inland fisheries management techniques. Particularly in Central and Western Europe where piscivorous fish are the target species of most commercial and recreational fisheries, an enhancement of the piscivores by stocking and harvest regulations may act successfully in the co‐management of ecosystem and fisheries. Guidelines are presented on how biomanipulation can be used as in lake rehabilitation by considering the objectives and constraints of traditional fisheries management. Alternatives in the decision tree are elucidated by examples from biomanipulations and lake management programmes in the temperate zone of Europe and North America. It is suggested that biomanipulation may support many lake rehabilitation programmes where fisheries’ stakeholders are the principal user groups.
Delayed development or congenital absence of a single first permanent molar in Japanese child patients
Authors: Nakano K. , Matsuoka T. , Takahashi A. , Matsumura M. , Sobue S. , Ooshima T.
Published: May 2004

Summary.
Objective. Delayed eruption of the first permanent molar (M1) is a relatively rare finding. This report describes the occurrence of delayed development and eruption of a single M1 in Japanese child patients.

Design. Cases were identified by surveying 353 orthopantomograms taken of child patients attending a Dental Hospital. Dental age, crown morphology and the presence of third permanent molars (M3) were determined from radiographs and clinical examination.

Setting. Osaka University Dental Hospital in Japan.

Results. Nine cases were identified from radiographs. The occlusal morphology of the affected molars showed a reduction of the distolingual cusp. Dental ages correlated more closely to chronological ages when the affected teeth were assumed to be second permanent molars (M2) than they did when the teeth were assumed to be M1. M3 proximate to the affected molar was congenitally absent in the orthopantomograms of all affected subjects.

Conclusions. It is suggested that in the cases seen here the affected teeth were likely to have been second permanent molars that had migrated mesially in association with the congenital absence of M1, although congenital absence of M1 has been reported to be extremely rare.
Self‐inflicted injury in a case of Hallervorden‐Spatz disease
Authors: Sheehy E.C. , Longhurst P. , Pool D. , Dandekar M.
Published: May 2004

Hallervorden‐Spatz disease (HSD) is a rare neurodegenerative disorder characterized by abnormally high deposits of iron in the brain. This report describes a child with HSD who presented with self‐inflicted ulceration of the lip and tongue, which was initiated during periods of intense oro‐facial spasms. Other findings included dental caries and trauma to the primary incisors. Comprehensive dental care was carried out under general anaesthesia. The self‐mutilation of the oro‐facial mucosa was eliminated by placement of upper and lower soft resin bite guards.
Sleep deprivation in honey bees1
Authors: Sauer Stefan , Herrmann Eva , Kaiser Walter
Published: May 2004

Rest at night in forager honey bees (Apis mellifera) meets essential criteria of sleep. This paper reports the effect of a 12‐h total sleep deprivation (SD) by forced activity on the behaviour of these animals. The behaviour of sleep‐deprived animals is compared with that of control animals under LD [periodic alternation between light (L) and darkness (D)] 12 : 12 hours. SD for 12 h during the first D period resulted in a significant difference with respect to the parameter ‘hourly amount of antennal immobility’ between sleep‐deprived and control animals during the remaining L and D periods. This difference did not occur in the L period following the deprivation night, but rather it became obvious at the beginning of the following D period. The increase of the amount of antennal immobility in sleep‐deprived bees was accompanied by an increase of the duration of episodes of antennal immobility. Moreover, the latency from ‘lights off’ to the first episode of antennal immobility lasting 20 s or longer (‘deep sleep latency’) tended to be shorter in sleep‐deprived than in control animals. Disturbing the bees during the day (L period) did not result in such differences between disturbed and control animals. Highest reaction thresholds in sleeping honey bees occur during long episodes of antennal immobility. We therefore conclude that honey bees compensate a sleep deficit by intensification (deepening) of the sleep process and thus that sleep in honey bees, like that in other arthropods and mammals, is controlled by regulatory mechanisms.
Does frequency of nocturnal urination reflect the severity of sleep‐disordered breathing?
Authors: Kaynak Hakan , Kaynak Derya , Oztura Ibrahim
Published: May 2004

Nocturia is an often‐described symptom of sleep‐disordered breathing (SDB). The aim of our study was to determine the frequency of nocturnal urination among patients with different severity of SDB and to find out whether frequency of nocturnal urination reflects the severity of disease. A retrospective chart review was conducted among 1075 subjects of suspected SDB. Nocturia was assessed using standard questionnaire evaluating a frequency of nocturnal urination. Subjects were divided into four groups of SDB based on the polysomnographic evaluation. In primary snoring group, 51% subjects did not complain nocturia, 28% subjects reported one time, 16% subjects reported two to three times and 5% subjects reported more than three times urination per night. Among patients with mild obstructive sleep apnea syndrome (OSAS), nocturnal urination was not reported by 36% and was reported one time by 34%, two to three times by 15%, more than 3 times by 15%. The corresponding frequencies among patients with moderate OSAS were 40, 31, 17 and 12%, and with severe OSAS were 23, 22, 23 and 32%, respectively. The severe OSA group was significantly different from other groups as regards the frequency of nocturnal urination (P < 0.001) while other OSA groups did not show any significance. Nocturnal urination of more than three times was significantly more reported by severe OSA patients ( P < 0.001) (positive predictive value = 0.71, negative predictive value = 0.62).
Early graft failure due to a veno‐occlusive disease after a pediatric living donor liver transplantation
Authors: Izaki Toshiya , Inomata Yukihiro , Asonuma Katsuhiro , Okajima Hideaki , Ohshiro Hajime , Ueno Mikako , Hamamoto Rieko , Iyama Ken‐ichi , Tanaka Koichi
Published: May 2004

Abstract:  A 10‐month‐old boy with biliary atresia after Kasai procedure underwent a living donor liver transplantation (LDLT). Five days after the LDLT, high fever and increased ascites followed by poor bile drainage was accompanied by elevation of serum liver enzymes. Liver biopsy showed occlusion of the central veins by fibro‐edematous endothelium and submassive necrosis of the parenchyma. Veno‐occlusive disease (VOD) was suspected, and re‐LDLT was urgently performed because of deterioration of hepatic failure. There are few cases of VOD after liver transplantation and this is the first one in an infant after LDLT.
Diurnal foraging‐mode shifts and food availability in nectarivore assemblages during winter
Authors: TIMEWELL C. A. R. , MAC NALLY R.
Published: May 2004

Abstract  Temporal fluctuations of food resources and foraging activities have been studied extensively, especially at longer timescales (monthly, seasonally, among years). However, short‐term variation (e.g. within days) is less well understood. Here we systematically quantified diurnal patterns of foraging by nectarivorous birds (meliphagid honeyeaters) that numerically dominated stands of a winter‐flowering eucalypt, the red ironbark, Eucalyptus tricarpa, in central Victoria, Australia. Diurnal variation in food resources also was measured. Data were collected in winter. Anecdotal observations that honeyeaters change from almost exclusive nectarivory early in the day to a higher fraction of insectivory – especially aerial hawking – later in the day were confirmed, although in areas of high flowering intensity, nectar‐feeding remained the dominant foraging activity throughout the day. Local climatic factors (ambient temperature, windiness and cloud cover) all varied systematically through the day. Together, results were consistent with a change in foraging emphasis to greater insectivory as a function of elevated activities of insects (especially aerial ones), which was probably fostered by higher ambient temperatures. Contrary to energetic expectations, the nectarivores were very active early in the morning when ambient temperatures averaged approximately 3°C, well below thermoneutral temperatures. We deduced that the potential benefits of gathering as much energy‐rich nectar as possible before it was depleted outweighed the high costs of activities at low temperatures.
Are locally rare species abundant elsewhere in their geographical range?
Authors: MURRAY BRAD R. , LEPSCHI BRENDAN J.
Published: May 2004

Abstract  Ecologists have long sought to understand why some species are rare and others common. For the most part, inconsistent relationships between local rarity and underlying mechanisms have emerged. One possibility for this inconsistency is that locally rare species may not always be rare. However, it is largely unknown whether most locally rare species in a community possess the capacity to become abundant elsewhere in their geographical range. Here, we identified 57 locally rare plant species of open forest in south‐eastern Australia. We found that most of these species (91%) occurred in higher abundance at other sites within their geographical range (somewhere‐abundant species), while the remaining small percentage of locally rare species were consistently rare (everywhere‐sparse species). Somewhere‐abundant species had significantly smaller seeds on average than everywhere‐sparse species in cross‐species regression analysis. This pattern was not maintained when the influence of other life‐history attributes was controlled for, or when phylogenetic relatedness among species was considered explicitly in phylogenetic regression analysis. In both cross‐species and phylogenetic regressions, somewhere‐abundant and everywhere‐sparse species did not differ significantly with respect to growth form, height, regeneration‐after‐fire strategy, or dispersal. Our findings provide further evidence for the notion that theories to account for local rarity which are couched in terms of within‐community interactions alone are incomplete for the majority of species, because they need to account for different outcomes in different places.
The influence of macro‐litterfall and forest structure on litterfall damage to seedlings
Authors: GILLMAN LEN N. , OGDEN JOHN , WRIGHT SHANE D. , STEWART KAREN L. , WALSH DWAYNE P.
Published: May 2004

Abstract  Microdisturbance to seedlings is important because it can differentially affect the mortality and recruitment of seedlings of forest tree species and thereby ultimately affect community composition. Microdisturbance due to litterfall has been shown to vary greatly in its influence on seedling survival among and within forests, and yet there have been no previous studies that investigate the cause of these differences. In this study the influence of macro‐litterfall on seedling damage is investigated in five complex temperate forests in New Zealand. Litterfall damage to artificial seedlings in these forests was strongly correlated with macro‐leaf‐fall (leaves > 30 cm × 1.5 cm) dry weight and total macro‐litterfall (leaves and deadwood > 30 cm × 1.5 cm) surface area (R2 = 0.99, P < 0.005 for each). Protective vegetation within 2 m of the ground (mostly lianes and woody shrubs) reduced the risk of litterfall damage by up to 84%. Hitherto unexplained differences in litterfall damage to seedlings found among, and within, forests (tropical and temperate) may therefore be due to differences in rates of macro‐leaf‐fall and forest structure. These results are important because they suggest that subtle differences in forest structure, and species composition, may influence regeneration patterns through the litterfall microdisturbance regime.
Emergence and survival of herbaceous seedlings in temperate grassy woodlands: Recruitment limitations and regeneration niche
Authors: CLARKE PETER J. , DAVISON ELIZABETH A.
Published: May 2004

Abstract  Field experiments examined herbaceous seedling emergence and survival in temperate grassy woodlands on the New England Tablelands of New South Wales. Effects of intensity of previous grazing, removal of ground cover by fire or clearing, burial of seeds, grazing and seed theft by ants on seedling emergence and survival were studied in two field experiments. Thirteen species with a range of traits were used in the experiments and their cumulative emergence was compared with laboratory germination studies. Field emergence correlated to laboratory germination but all species had lower emergence in the field. Little natural emergence of native species was observed in the field in unsown treatments. Short‐lived forbs had the highest emergence, followed by perennial grasses; rhizomatous graminoids and perennial forbs had the lowest emergence. Soil surface and cover treatments did not markedly enhance emergence suggesting that intertussock spaces were not prerequisites for forb emergence. No consistent pattern of enhanced emergence was found for any treatment combination across all species. Seedling survival varied among species, with perennial grasses and short‐lived forbs having the highest seedling mortality. Low mortality rates in the graminoids and rhizomatous forbs appeared partially to compensate for lower seedling emergence. All perennial grasses and some short‐lived forbs showed increased risk of mortality with grazing. Differences in emergence and survival of species were related to ground cover heterogeneity, soil surfaces and, to some extent, herbivory. The complexity of these patterns when superimposed on temporal variability suggests that no generalizations can be made about the regeneration niche of herbaceous species groups. Strong recruitment limitation and partitioning of resources in the regeneration niche may reduce competition among native species and explain the high species richness of the herbaceous layer in the temperate grassy communities of eastern Australia.
Estimation of plant and leaf area index using three techniques in a mature native eucalypt canopy
Authors: COOPS N. C. , SMITH M. L. , JACOBSEN K. L. , MARTIN M. , OLLINGER S.
Published: May 2004

Abstract  Leaf area index (L) is a critical variable in monitoring and modelling forest condition and growth and is therefore important for foresters and environmental scientists to measure routinely and accurately. We compared three different methods for estimating L: a plant canopy analyser (PCA), a point‐quadrat camera method and digital hemispherical photography at a native eucalypt forest canopy at Tumbarumba in southern New South Wales, Australia. All of these methods produced indirect estimates of L based on the close coupling between radiation penetration and canopy structure. The individual L estimates were compared, and the potential advantages and disadvantages of each method were discussed in relation to use in forest inventory and in field data collection programmes for remote sensing calibration and verification. The comparison indicated that all three methods, PCA, digital hemispherical photography and the modified point‐quadrat camera method, produced similar estimates with a standard error between techniques of less than 0.2 L units. All methods, however, provided biased estimates of L and calibration is required to derive true stand L. A key benefit, however, of all of these estimation methods is that observations can be collected in a short period of time (1–2 h of field‐work per plot).