bluuebunny/crossref_metadata_2025_split huggingface dataset:
The geographical range structure of the holly leaf‐miner. IV. Effects of variation in host‐plant quality
Authors: GASTON KEVIN J. , GENNEY DAVID R. , THURLOW MADDIE , HARTLEY SUE E. 
Published: August 2004

SummarySpatial variation and covariation in host‐plant quality, herbivore abundance and herbivore mortality were examined across the natural geographical range in Europe of hollyIlex aquifoliumand the host‐specific holly leaf‐minerPhytomyza ilicis.Although measures of host‐plant quality showed substantial between‐site variation, no simple spatial pattern in any of the measures (only phosphorus content and leaf mass showed correlations with latitude, longitude or altitude) was detected, and few correlations with tree or local site characteristics.In contrast, measures of the abundance of the leaf‐miner exhibited marked spatial patterns, resulting in a lack of simple covariance between leaf‐miner abundance and host‐plant quality.Different apparent mortalities of the leaf‐miner exhibited varied spatial patterns in their intensity, but no evidence of range‐wide density dependence, again resulting in few patterns of covariance between intensity of mortality and measures of host‐plant quality.The population dynamics of the holly leaf‐miner across its geographical range are complex. At any site, the mortality that a population experiences is the sum of largely independent yet spatially structured components, against a background of varying host‐plant quality. Despite lacking any marked spatial structure, host‐plant quality may have important local effects. These are difficult to detect regionally, and thus may principally contribute noise to regional patterns of levels of oviposition, abundance and mortality.
Bottom‐up density regulation in the holly leaf‐miner Phytomyza ilicis
Authors: EBER SABINE 
Published: August 2004

Summary
The holly leaf‐miner Phytomyza ilicis Curtis shows density patterns typical for non‐eruptive leaf‐miners, with stable mean densities, but consistently different infestation rates on individual trees.
To identify the mechanisms responsible for these patterns the population dynamics of P. ilicis were studied during an 8‐year period on 92 host trees in 15 holly patches. The patterns of oviposition, mining and survival and the dominant sources and rates of mortality were monitored. The impact of tree and patch parameters on leaf‐miner population dynamics was analysed, and the dispersal ability of P. ilicis was evaluated experimentally.
Infestation differences among trees were due to host selection, which determined egg numbers on individual trees and was explained partly by holly variety and leaf availability.
Egg distributions on medium to highly infested host trees were aggregated, suggesting limits in the availability of young leaves for oviposition.
Due to a suite of mortality factors mean survival rates of P. ilicis were below 10% and did not show a relationship with host choice.
There was strongly density‐dependent pre‐mine mortality most probably caused by intraspecific competition in the leaf midrib. This lead to the formation of a single mine on most leaves. There was a weak density‐dependent effect of mine density on miscellaneous larval death and on the attack rates of the larval parasitoid Chrysocaris gemma.
In the holly leaf‐miner system phenology effects set a population ceiling delimited by the availability of oviposition sites. The resulting egg distribution determined the impact of density‐dependent intraspecific competition in the leaf midrib. The incidence of larval competition was therefore not a function of density per se, but density‐relative to the availability of a limiting resource, namely suitable young leaves for oviposition.
Metabolic response to temperature variation in the great tit: an interpopulation comparison
Authors: BROGGI JULI , ORELL MARKKU , HOHTOLA ESA , NILSSON JAN–ÅKE 
Published: August 2004

SummaryWe studied the resting metabolic rate (MR) from two great titParus major(Linnaeus) populations living in different winter regimes. Birds from the two different localities were exposed individually to +25 °C, 0 °C and −10 °C for the night in three consecutive sessions in random order.Birds from Lund (Sweden) had a lower basal MR, as measured at thermoneutrality (+25 °C), than had birds from Oulu (Finland). Nevertheless, below thermoneutrality, birds from Oulu spent relatively more energy, especially at −10 °C.Although the energy needed for thermoregulation decreased with increasing basal MR this relation is at a higher metabolic cost for birds in Oulu than for birds in Lund.The higher basal MR in Oulu is probably a consequence of a higher maximal MR needed in the severe cold. Further, the observed MRs below thermoneutrality are lower than expected from published data. This suggests that all birds were probably hypothermic at −10 °C, particularly Lund birds, and that the use of controlled hypothermia in great tits may be more common than thought previously. Great tits seem to rely primarily on metabolic adjustment to cope with the harsh climatic conditions in the northernmost parts of its distribution.
State‐owned enterprises going public The case of China
Authors: Wang Xiaozu , Xu Lixin Colin , Zhu Tian 
Published: August 2004

AbstractPublic listing is a key reform measure for large state‐owned enterprises (SOEs) in China. We find evidence that public listing lowers state ownership significantly, lessens firms’ reliance on debt finance, and allows firms to increase capital expenditure, at least temporarily. We also find that ownership structure affects post‐listing performance. However, we find no statistical evidence of a positive effect of public listing on firms’ profitability. We suggest alternative interpretations of the last finding.
What determines public education expenditures in Russia?1
Authors: Verbina Inna , Chowdhury Abdur 
Published: August 2004

AbstractRecent studies suggest that the allocation of expenditures in education is important for growth. The state of public education spending in many transition economies highlights the need for an assessment of the nature of education expenditures in these countries. This paper attempts to fill this gap in the literature by estimating the determinants of education expenditures in the Russian Federation. Results from panel data analysis show that revenue and the student‐population ratio have a positive impact on education expenditures while the effect of population density is negative. Three regional variables also show significant impact. The income and price elasticity of public education expenditures are estimated to be 0.57 and −0.18, respectively, a result comparable to studies from other countries. The results presented here provide insight into how fiscal institutions and the structure of the political process in Russia may affect the degree of resource allocation in the educational sector during the transition process.
Do family resources matter? Educational attainment during transition in Poland*
Authors: Beblo Miriam , Lauer Charlotte 
Published: August 2004

AbstractWe analyse the relationship between family background and children's educational attainment in the 1990s in Poland. If parental poverty affects children's educational prospects, the increase in social inequalities observed in the Polish transition process will be transmitted between generations. We apply an ordered probit model of educational attainment on longitudinal data from the Polish Labour Force Survey. Surprisingly, parents’ income and their labour market status have only a weak impact on children's education. Parents’ schooling, however, is strongly related to children's, and so are household structure, city size, and region of residence. We conclude that, if transmission of inequality takes place between generations, this seems to be primarily caused by the inheritance of human capital rather than by pure wealth effects.
Multinational Diversification and Corporate Performance: Evidence from European Firms
Authors: Mathur Ike , Singh Manohar , Gleason Kimberly C. 
Published: August 2004

Abstract We investigate the empirical relationship between accounting based measures of performance and the degree of multinational diversification for a set of European chemical industry firms. We find that for these firms, the degree of multinational diversification is strongly related to superior financial performance. The results hold for each of the three sample years. The findings suggest that multinational firms outperform purely domestic and exporting firms. The results provide strong support for gains from multinational diversification. The results indicate that while greater European unification may have eroded potential benefits of exploiting international capital and product market imperfections, the benefits of firm specific economies of scope and scale as well as managerial and financial synergies are still realised through exports.
Perceived peer smoking prevalence and its association with smoking behaviours and intentions in Hong Kong Chinese adolescents
Authors: Lai Man Kin , Ho Sai Yin , Lam Tai Hing 
Published: August 2004

ABSTRACTBackground  Among the many personal, social and environmental risk factors of adolescence smoking, normative beliefs stand out for their potential to be modified with factual information on smoking prevalence.Aims  To study the perceived peer smoking prevalence and its association with smoking behaviours in Hong Kong Chinese adolescents.Design and setting  Cross‐sectional territorial‐wide school‐based survey conducted in 64 randomly selected secondary schools in Hong Kong.Participants  A total of 13 280 forms 1–3 students (equivalent to grades 7–9 in the United States) aged 12–16 years.Measurements  Perceived peer smoking prevalence, smoking status, intention to smoke in future, other smoking‐related factors and demographic information.Findings  Overestimation of peer smoking prevalence was observed regardless of gender and smoking status, and was more common in girls (69.4%) than boys (61.0%), and in experimental (74.3%) and current smokers (85.4%) than in never smokers (60.7%). Boys who overestimated and grossly overestimated (over two times) peer smoking were more likely to be current smokers, with adjusted odds ratios and 95% confidence intervals (95% CI) of 1.95 (1.24–3.07) and 3.52 (2.37–5.24) (P for trend <0.001). Similarly, boys who grossly overestimated peer smoking were 76% (95% CI: 41–120%) more likely to have ever smoked.Conclusion  Overestimation of peer smoking prevalence was common in Hong Kong Chinese boys and girls, and was associated with current and ever smoking in boys. These findings have important implications on normative education in adolescence smoking prevention programmes.
Alcohol abuse in a metropolitan city in China: a study of the prevalence and risk factors
Authors: Jiafang Zhang , Jiachun Wang , Yunxia Lu , Xiaoxia Qiu , Ya Fang 
Published: August 2004

ABSTRACTAims  To investigate the prevalence of alcohol abuse in modern China and to explore the risk factors that may be associated with alcohol abuse.Design  A face‐to‐face interview was carried out in a random sample with 2327 respondents.Setting  Respondents were selected randomly from Wuhan City, Hubei Province, China, between May and June 2002.Participants  Fifteen−65‐year‐old urban Chinese adults.Measurements  Scores for alcohol abuse and related risk factors were the main measures.Findings  (1) Nearly 15% of urban Chinese adults aged 15–65 were alcohol abusers. (2) Deviant drinking habits of mother, schoolmates, colleagues or friends all had a negative impact on the respondent's alcohol drinking behaviours, and higher economic status, current smokers, being male and being older were identified as risk factors related to alcohol abuse. In particular, if a drinker's mother used alcohol frequently then this drinker was more likely to become an alcohol abuser than those drinkers whose mothers did not use alcohol frequently (P = 0.0001). Fathers’ drinking behaviours do not have a significant impact on the alcohol abusers.Conclusions  In addition to common risk factors such as economic status, deviant peers’ and fellows’ drinking behaviours and negative attitudes to alcohol drinking, maternal alcohol drinking habit influenced significantly the offspring's drinking habits. Therefore, efficient intervention and education of healthy drinking habits in early motherhood is necessary for Chinese women.
Randomized controlled trial of a brief behavioural intervention for reducing hepatitis C virus risk practices among injecting drug users
Authors: Tucker Thamizan , Fry Craig L. , Lintzeris Nick , Baldwin Simon , Ritter Alison , Donath Susan , Whelan Greg 
Published: August 2004

ABSTRACTAim  To develop and evaluate a brief intervention for reducing risk behaviours associated with HCV transmission in injecting drug users (IDU).Design  Randomized controlled trial of an individually tailored brief behavioural intervention (BBI) (experimental) versus a standardized educational intervention (control).Setting  Specialist drug treatment facility in Melbourne, Australia.Participants  One hundred and forty‐five IDU (aged 18 or over, injecting at least weekly in the preceding 6 months) recruited and randomized to the experimental condition (n = 73) or the control condition (n = 72).Interventions  The BBI was based on the Blood‐Borne Virus Transmission Risk Assessment Questionnaire (BBV‐TRAQ)—a standardized blood‐borne virus risk assessment instrument comprising injecting risk, sexual risk and other skin penetration risk subscales. The BBV‐TRAQ was used to identify individual HCV risk practices and to tailor the 30‐minute experimental BBI. Control participants received a standardized HCV educational session, using current educational materials.Main outcome measures  BBV‐TRAQ subscale and total scores and measures of participant satisfaction.Results  One hundred and twenty‐four participants (86%) were followed‐up at 4 weeks (±7 days). Analyses revealed a significant reduction in HCV risk behaviours for both groups at 1‐month follow‐up, with participants in the experimental BBI condition reporting higher overall satisfaction with the intervention compared to the control group.Conclusions  Both groups reported significant reductions in risk behaviour, indicating that while BBI methods hold promise for HCV education and prevention, they were not demonstrated to be more effective than the provision of standard educational materials. Future research could evaluate the efficacy of the BBV‐TRAQ as a risk behaviour intervention and counselling tool in clinical, NSP and peer education settings.
Longitudinal surveys of prevalence rates and use patterns of illicit drugs at selected high‐prevalence areas in China from 1993 to 2000
Authors: Hao Wei , Su Zhonghua , Xiao Shuiyuan , Fan Changhe , Chen Hongxian , Liu Tieqiao , Young Deson 
Published: August 2004

ABSTRACTAims  To identify the prevalence, patterns and trends of illicit drug use in the general population of selected high‐prevalence areas in China between 1993 and 2000.Design, setting and participants  Cluster sampling was employed and the Epidemiological Inventory for Illicit Drug Use (EIIDU) used as survey instrument. In 1993, 1996 and 2000, 56 792, 67 319 and 53 747 individuals aged 15 or above in community were interviewed, respectively, at the three time‐points.Measurements  Demographics and drug‐related data were collected and the prevalence patterns of illicit drug are described.Findings  The life‐time prevalences of illicit drug use in the three consecutive surveys in 1993, 1996 and 2000 were 1.08, 1.60 and 1.52%, respectively, and the 1‐year prevalence rates were 0.91, 1.17 and 1.17%, respectively. Heroin was the first choice for drug use (51.8% in 1993, 83.4% in 1993 and 95.9% in 2000). The two most frequent routes of drug administration were inhalation (89.2% in 1993, 60.1% in 1996 and 93.5% in 2000) and intravenous injection (27.2% in 1993, 31.0% in 1996 and 25.7% in 2000).Conclusion  At least for the time being, illicit drug use may have plateaued in these selected high‐prevalence areas.
Respiration and annual fungal production associated with decomposing leaf litter in two streams
Authors: Carter M. D. , Suberkropp Keller 
Published: August 2004

Summary1. We compared fungal biomass, production and microbial respiration associated with decomposing leaves in one softwater stream (Payne Creek) and one hardwater stream (Lindsey Spring Branch).2. Both streams received similar annual leaf litter fall (478–492 g m−2), but Lindsey Spring Branch had higher average monthly standing crop of leaf litter (69 ± 24 g m−2; mean ± SE) than Payne Creek (39 ± 9 g m−2).3. Leaves sampled from Lindsey Spring Branch contained a higher mean concentration of fungal biomass (71 ± 11 mg g−1) than those from Payne Creek (54 ± 8 mg g−1). Maximum spore concentrations in the water of Lindsay Spring Branch were also higher than those in Payne Creek. These results agreed with litterbag studies of red maple (Acer rubrum) leaves, which decomposed faster (decay rate of 0.014 versus 0.004 day−1), exhibited higher maximum fungal biomass and had higher rates of fungal sporulation in Lindsey Spring Branch than in Payne Creek.4. Rates of fungal production and respiration per g leaf were similar in the two streams, although rates of fungal production and respiration per square metre were higher in Lindsey Spring Branch than in Payne Creek because of the differences in leaf litter standing crop.5. Annual fungal production was 16 ± 6 g m−2 (mean ± 95% CI) in Payne Creek and 46 ± 25 g m−2 in Lindsey Spring Branch. Measurements were taken through the autumn of 2 years to obtain an indication of inter‐year variability. Fungal production during October to January of the 2 years varied between 3 and 6 g m−2 in Payne Creek and 7–27 g m−2 in Lindsey Spring Branch.6. Partial organic matter budgets constructed for both streams indicated that 3 ± 1% of leaf litter fall went into fungal production and 7 ± 2% was lost as respiration in Payne Creek. In Lindsey Spring Branch, fungal production accounted for 10 ± 5% of leaf litter fall and microbial respiration for 13 ± 9%.
Microbial activities in the burrow environment of the potamal mayfly Ephoron virgo
Authors: Stief Peter , Altmann Dörte , de Beer Dirk , Bieg Rosita , Kureck Armin 
Published: August 2004

Summary1. The impact of burrowing larvae of Ephoron virgo (Ephemeroptera, Polymitarcidae) on sediment microbiology has not been previously investigated because of difficulties in sampling the sediment of large rivers under in situ conditions. Therefore, we conducted experiments in the on‐ship Ecological Rhine Station of the University of Cologne (Germany), in which ambient conditions of the River Rhine can be closely mimicked.2. In two consecutive seasons, experimental flow channels were stocked with Ephoron larvae and continuously supplied with water taken directly from the River Rhine. Sediment from the immediate vicinity of Ephoron burrows (i.e. U‐shaped cavities reaching 10–80 mm deep into the sediment) and bulk sediment samples were analysed for (i) particulate organic matter content, (ii) microscale in situ distribution of O2, NO, and NH, and (iii) potential activities of exoenzymes.3. Sediment surrounding the Ephoron burrows had markedly higher organic matter contents and exoenzyme activities compared with the bulk sediment. Microsensor measurements demonstrated that local O2 and NO penetration into the sediment were greatly enhanced by larval ventilation behaviour. Volumetric O2 and NO turnover rates that were calculated from steady state concentration profiles measured directly in the burrow lining were considerably higher than at the sediment surface.4. In the sediment of the fast flowing River Rhine Ephoron burrows are preferential sites of organic matter accumulation and dissolved oxidant penetration. Our data suggest that the burrows are surrounded by a highly active microbial community that responds to the inputs from the water column with elevated O2 and NO turnover, and release of exoenzymes into the sediment pore water. Especially during periods of mass occurrence, the larvae of E. virgo may thus significantly contribute (i) to the ecological connection between the water column and the sediment and (ii) to biogeochemical processing of organic matter in the riverbed.
Identifying the scales of variability in stream macroinvertebrate abundance, functional composition and assemblage structure
Authors: Heino Jani , Louhi Pauliina , Muotka Timo 
Published: August 2004

Summary1. Many natural ecosystems are heterogeneous at scales ranging from microhabitats to landscapes. Running waters are no exception in this regard, and their environmental heterogeneity is reflected in the distribution and abundance of stream organisms across multiple spatial scales.2. We studied patchiness in benthic macroinvertebrate abundance and functional feeding group (FFG) composition at three spatial scales in a boreal river system. Our sampling design incorporated a set of fully nested scales, with three tributaries, two stream sections (orders) within each tributary, three riffles within each section and ten benthic samples in each riffle.3. According to nested anovas, most of the variation in total macroinvertebrate abundance, abundances of FFGs, and number of taxa was accounted for by the among‐riffle and among‐sample scales. Such small‐scale variability reflected similar patterns of variation in in‐stream variables (moss cover, particle size, current velocity and depth). Scraper abundance, however, varied most at the scale of stream sections, probably mirroring variation in canopy cover.4. Tributaries and stream sections within tributaries differed significantly in the structure and FFG composition of the macroinvertebrate assemblages. Furthermore, riffles in headwater (second order) sections were more variable than those in higher order (third order) sections.5. Stream biomonitoring programs should consider this kind of scale‐dependent variability in assemblage characteristics because: (i) small‐scale variability in abundance suggests that a few replicate samples are not enough to capture macroinvertebrate assemblage variability present at a site, and (ii) riffles from the same stream may support widely differing benthic assemblages.