bluuebunny/crossref_metadata_2025_split huggingface dataset:
Above‐ground space sequestration determines competitive success in juvenile beech and spruce trees
Authors: Kozovits Alessandra R. , Matyssek Rainer , Winkler J. Barbro , Göttlein Axel , Blaschke Helmut , Grams Thorsten E. E. 
Published: June 2005

SummaryA 2‐yr phytotron study was conducted to investigate the intra‐ and inter‐specific competitive behaviour of juvenile beech (Fagus sylvatica) and spruce (Picea abies). Competitiveness was analysed by quantifying the resource budgets that occur along structures and within occupied space of relevance for competitive interaction.Ambient and elevated CO2and ozone (O3) regimes were applied throughout two growing seasons as stressors for provoking changes in resource budgets, growth and allocation to facilitate the competition analysis. The hypothesis tested was that the ability to sequester space at low structural cost will determine the competitive success.Spruce was a stronger competitor than beech, as displayed by its higher above‐ground biomass increments in mixed culture compared with monoculture. A crucial factor in the competitive success of spruce was its ability to enlarge crown volume at low structural costs, supporting the hypothesis.Interspecific competition with spruce resulted in a size‐independent readjustment of above‐ground allocation in beech (reduced leaf : shoot biomass ratio). The efficient use of resources for above‐ground space sequestration proved to be a parameter that quantitatively reflects competitiveness.
Identification of perennial ryegrass (Lolium perenne(L.)) and meadow fescue (Festuca pratensis(Huds.)) candidate orthologous sequences to the riceHd1(Se1) and barleyHvCO1 CONSTANS‐like genes through comparative mapping and microsynteny
Authors: Armstead I. P. , Skøt L. , Turner L. B. , Skøt K. , Donnison I. S. , Humphreys M. O. , King I. P. 
Published: June 2005

SummaryMicrosynteny with rice and comparative genetic mapping were used to identify candidate orthologous sequences to the riceHd1(Se1) gene inLolium perenneandFestuca pratensis.AF. pratensisbacterial artificial chromosome (BAC) library was screened with a marker (S2539) physically close toHd1in rice to identify the equivalent genomic region inF. pratensis. The BAC sequence was used to identify and map the same region inL. perenne.Predicted protein sequences forL. perenneandF. pratensisHd1 candidates (LpHd1 and FpHd1) indicated they were CONSTANS‐like zinc finger proteins with 61–62% sequence identity with rice Hd1 and 72% identity with barley HvCO1. LpHd1 and FpHd1 were physically linked in their respective genomes (< 4 kb) to marker S2539, which was mapped toL. perennechromosome 7.The identified candidate orthologues of riceHd1and barleyHvCO1inL. perenneandF. pratensismap to chromosome 7, a region of theL. perennegenome which has a degree of conserved genetic synteny both with rice chromosome 6, which containsHd1, and barley chromosome 7H, which containsHvCO1.
Productivity, leaf traits and carbon isotope discrimination in 29 Populus deltoides × P. nigra clones
Authors: Monclus Romain , Dreyer Erwin , Delmotte Francis M. , Villar Marc , Delay Didier , Boudouresque Eric , Petit Jean‐Michel , Marron Nicolas , Bréchet Claude , Brignolas Franck 
Published: June 2005

Summary

Here we tested whether some leaf traits could be used as predictors for productivity in a range of Populus deltoides × P. nigra clones. These traits were assessed in 3‐yr‐old rooted cuttings from 29 clones growing in an open field trial, in a five randomized complete block design, under optimal irrigation.
Variables were assigned to four groups describing productivity (above‐ground biomass, total leaf area), leaf growth (total number of leaves increment rate), leaf structure (area of the largest leaf, specific leaf area, carbon and nitrogen contents), and carbon isotope discrimination in the leaves (Δ).
High‐yielding clones displayed larger total leaf area and individual leaf area, while no correlation could be detected between productivity and either leaf structure or Δ. By contrast, Δ was negatively correlated with number of leaves increment rate and leaf N content.
Our study shows that there is a potential to improve water‐use efficiency in poplar without necessarily reducing the overall productivity.
Gene expression patterns of trembling aspen trees following long‐term exposure to interacting elevated CO2 and tropospheric O3
Authors: Gupta P. , Duplessis S. , White H. , Karnosky D. F. , Martin F. , Podila G. K. 
Published: June 2005

Summary

Expression of 4600 poplar expressed sequence tags (ESTs) was studied over the 2001–2002 growing seasons using trees of the moderately ozone (O3)‐tolerant trembling aspen (Populus tremuloides) clone 216 exposed to elevated CO2 and/or O3 for their entire 5‐yr life history.
Based on replication of the experiment in years 2001 and 2002, 238 genes showed qualitatively similar expression in at least one treatment and were retained for analysis. Of these 238 genes, 185 were significantly regulated (1.5‐fold) from one year to the other in at least one treatment studied. Less than 1% of the genes were regulated 2‐fold or more.
In the elevated CO2 treatment, relatively small numbers of genes were up‐regulated, whereas in the O3 treatment, higher expression of many signaling and defense‐related genes and lower expression of several photosynthesis and energy‐related genes were observed. Senescence‐associated genes (SAGs) and genes involved in the flavanoid pathway were also up‐regulated under O3, with or without CO2 treatment. Interestingly, the combined treatment of CO2 plus O3 resulted in the differential expression of genes that were not up‐regulated with individual gas treatments.
This study represents the first investigation into gene expression following long‐term exposure of trees to the interacting effects of elevated CO2 and O3 under field conditions. Patterns of gene‐specific regulation described in this study correlated with previously published physiological responses of aspen clone 216.
Genetic architecture of qualitative and quantitativeMelampsora larici‐populinaleaf rust resistance in hybrid poplar: genetic mapping and QTL detection
Authors: Jorge V. , Dowkiw A. , Faivre‐Rampant P. , Bastien C. 
Published: June 2005

SummaryIn order to elucidate the genetic control of resistance toMelampsora larici‐populinaleaf rust in hybrid poplars, aPopulus deltoides × P. trichocarpa F1progeny was analysed for qualitative and quantitative rust resistances.This progeny was evaluated for three components of quantitative resistance (latent period, uredinia number and uredinia size) to sevenM. larici‐populinastrains in controlled conditions, and for one component of field susceptibility (rust colonization on the most infected leaf).One qualitative resistance locus inherited fromP. deltoides,R1, was localized on the genetic map. It segregates 1 : 1 in theF1progeny and is effective against four of the studied strains. QTL analysis was performed separately onR1andr1genotype subsets. An additional detection was conducted on the entireF1progeny for the three strains able to overcomeR1and for MAX2. A total of nine QTLs were detected. Two had large, broad‐spectrum effects. One (RUS) is inherited from theP. trichocarpaparent; the other is inherited fromP. deltoides andcolocalized withR1. Seven QTLs had only limited and specific effects. Significant interaction effects were detected mainly between the two major QTLs.Implications of these results for durable resistance breeding strategies, and possible benefits from thePopulusgenome sequence, are discussed.
Measuring tree root respiration using 13C natural abundance: rooting medium matters
Authors: Cheng Weixin , Fu Shenglei , Susfalk Richard B. , Mitchell Robert J. 
Published: June 2005

Summary

Tree root respiration utilizes a major portion of the primary production in forests and is an important process in the global carbon cycle. Because of the lack of ecologically relevant methods, tree root respiration in situ is much less studied compared with above‐ground processes such as photosynthesis and leaf respiration.
This study introduces a new 13C natural tracer method for measuring tree root respiration in situ. The method partitions tree root respiration from soil respiration in buried root chambers.
Rooting media substantially influenced root respiration rates. Measured in three media, the fine root respiration rates of longleaf pine were 0.78, 0.27 and 0.18 mg CO2 carbon mg−1 root nitrogen d−1 at 25°C in the native soil, tallgrass prairie soil, and sand–vermiculite mixture, respectively. Compared with the root excision method, the root respiration rate of longleaf pine measured by the field chamber method was 18% higher when using the native soil as rooting medium, was similar in the prairie soil, but was 42% lower if in the sand–vermiculite medium.
This natural tracer method allows the use of an appropriate rooting medium and is capable of measuring root respiration nondestructively in natural forest conditions.
Nitrogen storage and seasonal nitrogen cycling in Populus: bridging molecular physiology and ecophysiology
Authors: Cooke Janice E. K. , Weih Martin 
Published: June 2005

SummaryWhile both annual and perennial plants store nitrogen resources during the growing season, seasonal N cycling is a hallmark of the perennial habit. In Populus the vegetative storage proteins BSP, WIN4 and PNI288 all play a role in N storage during active growth, whereas BSP is the major form of reduced N storage during winter dormancy. In this review we explore cellular and molecular events implicated in seasonal N cycling in Populus, as well as environmental cues that modulate both the phenology of seasonal N cycling, and the efficiency and proficiency of autumn N resorption. We highlight recent advances that have been made using Populus genomics resources to address processes germane to seasonal N cycling. Genetic and genecological studies are enabling us to connect our understanding of seasonal N cycling at molecular and cellular levels with that at ecophysiological levels. With the genomics resources and foundational knowledge that are now in place, Populus researchers are poised to build an integrative understanding of seasonal N cycling that spans from genomes to ecosystems.
Characterization of transgenic poplar with ectopic expression of pine cytosolic glutamine synthetase under conditions of varying nitrogen availability
Authors: Man Hui‐min , Boriel Randall , El‐Khatib Rami , Kirby Edward G. 
Published: June 2005

Summary

The present study addresses the hypothesis that enhanced expression of glutamine synthetase (GS) in transgenic poplar, characterized by the ectopic expression of pine cytosolic GS, results in an enhanced efficiency of nitrogen (N) assimilation and enhanced growth.
Transgenic and control poplar were supplied with low and high N levels and the role of ectopic expression of the pine GS in growth and N assimilation was assessed by using amino acid analysis, 15N enrichment, biochemical analyses, and growth measurements.
While leaves of transgenic poplar contained 85% less (P < 0.01) free ammonium than leaves of nontransgenic control plants, leaves of transgenics showed increases in the levels of free glutamine and total free amino acids. Transgenic poplar lines also displayed significant increases in growth parameters when compared with controls grown under both low (0.3 mm) and high (10 mm) nitrate conditions. Furthermore, 15N‐enrichment experiments showed that 27% more (P < 0.05) 15N was incorporated into structural compounds in transgenic lines than in nontransgenic controls.
Using the methods described here, we present direct evidence for increased N assimilation efficiency and growth in GS transgenic lines.
Breast cancer risk among Finnish cabin attendants: a nested case-control study
Authors: Kojo K , Pukkala E , Auvinen A 
Published: June 2005

Background:Earlier studies have found increased breast cancer risk among female cabin crew. This has been suggested to reflect lifestyle factors (for example, age at first birth), other confounding factors (for example, age at menarche), or occupational factors such as exposure to cosmic radiation and circadian rhythm alterations due to repeated jet lag.Aims:To assess the contribution of occupational versus lifestyle and other factors to breast cancer risk among cabin attendants in Finland.Methods:A standardised self-administered questionnaire on demographic, occupational, and lifestyle factors was given to 1041 cabin attendants. A total of 27 breast cancer cases and 517 non-cases completed the questionnaire. Breast cancer diagnoses were confirmed through the Finnish Cancer Registry. Exposure to cosmic radiation was estimated based on self-reported flight history and timetables. A conditional logistic regression model was used for analysis.Results:In the univariate analysis, family history of breast cancer (OR = 2.67, 95% CI: 1.00 to 7.08) was the strongest determinant of breast cancer. Of occupational exposures, sleep rhythm disruptions (OR = 1.72, 95% CI: 0.70 to 4.27) were positively related and disruption of menstrual cycles (OR = 0.71, 95% CI: 0.26 to 1.96) negatively related to breast cancer. However, both associations were statistically non-significant. Cumulative radiation dose (OR = 0.99, 95% CI: 0.83 to 1.19) showed no effect on breast cancer.Conclusions:Results suggest that breast cancer risk among Finnish cabin attendants is related to well established risk factors of breast cancer, such as family history of breast cancer. There was no clear evidence that the three occupational factors studied affected breast cancer risk among Finnish flight attendants.
Appropriate use of personal protective equipment among healthcare workers in public sector hospitals and primary healthcare polyclinics during the SARS outbreak in Singapore
Authors: Chia S E , Koh D , Fones C , Qian F , Ng V , Tan B H , Wong K S , Chew W M , Tang H K , Ng W , Muttakin Z , Emmanuel S , Fong N P , Koh G , Lim M K 
Published: June 2005

Background:Singapore was affected by an outbreak of severe acute respiratory syndrome (SARS) from 25 February to 31 May 2003, with 238 probable cases and 33 deaths.Aims:To study usage of personal protective equipment (PPE) among three groups of healthcare workers (HCWs: doctors, nurses, and administrative staff), to determine if the appropriate PPE were used by the different groups and to examine the factors that may determine inappropriate use.Methods:A self-administered questionnaire survey of 14 554 HCWs in nine healthcare settings, which included tertiary care hospitals, community hospitals, and polyclinics, was carried out in May–July 2003. Only doctors, nurses, and clerical staff were selected for subsequent analysis.Results:A total of 10 236 valid questionnaires were returned (70.3% response); 873 doctors, 4404 nurses, and 921 clerical staff were studied. A total of 32.5% of doctors, 48.7% of nurses, and 77.1% of the administrative staff agreed that paper and/or surgical masks were “useful in protecting from contracting SARS”. Among this group, 23.6% of doctors and 42.3% of nurses reported working with SARS patients. The view that a paper and/or surgical mask was adequate protection against SARS was held by 33.3% of doctors and 55.9% of nurses working at the A&E unit, 30.5% of doctors and 49.4% of nurses from medical wards, and 27.5% of doctors and 37.1% of nurses from intensive care units. Factors which predicted for agreement that paper and/or surgical masks were protective against SARS, included HCW’s job title, reported contact with SARS patients, area of work, and Impact Events Scale scores.Conclusion:A variety of factors determine appropriate use of personal protective equipment by HCWs in the face of a major SARS outbreak.
A randomised controlled trial of postural interventions for prevention of musculoskeletal symptoms among computer users
Authors: Gerr F , Marcus M , Monteilh C , Hannan L , Ortiz D , Kleinbaum D 
Published: June 2005

Aims:To examine the effect of two workstation and postural interventions on the incidence of musculoskeletal symptoms among computer users.Methods:Randomised controlled trial of two distinct workstation and postural interventions (an alternate intervention and a conventional intervention) among 376 persons using computer keyboards for more than 15 hours per week. The incidence of neck/shoulder symptoms and hand/arm symptoms during six months of follow up among individuals in the intervention groups was compared to the incidence in computer users who did not receive an intervention (comparison group). For individuals in the intervention groups, study staff adjusted workstations, where possible, and trained individuals to assume the intervention postures. Individuals reported musculoskeletal symptoms in a weekly diary. Participants who reported discomfort intensity of 6 or greater on a 0–10 visual analogue scale or who reported musculoskeletal symptoms requiring use of analgesic medication were considered symptomatic.Results:There were no significant differences in the incidence of musculoskeletal symptoms among the three intervention groups. Twenty two (18.5%) participants in the alternate intervention group, 25 (20.2%) in the conventional intervention group, and 25 (21.7%) in the comparison group developed incident arm or hand symptoms. Thirty eight (33.3%) participants in the alternate intervention group, 36 (31.0%) in the conventional intervention group, and 33 (30.3%) in the comparison group developed incident neck or shoulder symptoms. Compliance with all components of the intervention was attained for only 25–38% of individuals, due mainly to the inflexibility of workstation configurations.Conclusions:This study provides evidence that two specific workplace postural interventions are unlikely to reduce the risk of upper extremity musculoskeletal symptoms among computer users.
Cancer incidence in the Swedish leather tanning industry: updated findings 1958–99
Authors: Mikoczy Z , Hagmar L 
Published: June 2005

Aims:To assess how a 10 year extension of the follow up period affected cancer incidence in the Swedish leather tanning cohort.Methods:A cohort of 2027 tannery workers (of which 482 were women) who had been employed for at least one year between 1900 and 1989 at one of three Swedish leather tanneries, was established. The start of observation varied between 1958 and 1966 for the three plants. Through linkage with the Swedish Cancer Registry, incident cancer cases were recorded up to 1999. Cause specific expected cancer incidence was calculated for 1958–99 based on calendar year, sex, and five year age group specific incidence rates for the counties where the plants had been located. Altogether 56 022 person-years at risk were generated.Results:A total of 351 incident cancer cases were observed compared to 302 expected, which resulted in an increased standardised incidence ratio (SIR) of 1.16 (95% CI 1.04 to 1.29). An enhanced risk for prostate cancer was observed (SIR 1.44, 95% CI 1.10 to 1.86), mainly attributable to the later part of the observation period (1990–99). In this updated analysis the previously observed risk excess for soft tissue sarcomas was no longer significant (SIR 2.62, 95% CI 0.96 to 5.70). For multiple myelomas and sinonasal cancer the slight non-significant excesses remained, still based on very few cases.Conclusions:The increased risk for prostate cancer in the present study might be a chance finding, but is noteworthy, since it is in acccordance with the finding of increased SIR for prostate cancer among leather workers in another recent Swedish study. Moreover, excess risks for prostate cancer among farmers have been reported, indicating pesticides as possible causative agents. Leather tanners have also been exposed to pesticides.
Mortality in the UK industrial silica sand industry: 2. A retrospective cohort study
Authors: Brown T P , Rushton L 
Published: June 2005

Aims:To evaluate the mortality experience of a cohort of employees in the UK silica sand industry exposed to respirable crystalline silica (RCS).Methods:A retrospective cohort mortality study followed all workers to 2001 with at least one year’s employment at one of seven UK silica sand producing quarries between 1950 and 1986. Each worker was assigned a job category and cumulative exposure to RCS was estimated using a job-exposure matrix.Results:A total of 764 deaths were identified in 2703 cohort members. The overall mortality rate for the cohort was lower than would be expected in the general population. Mortality from circulatory and respiratory disease was also less than expected, but death due to pneumoconiosis was slightly raised (two deaths). Mortality from all cancers was slightly decreased. Mortality was not raised in any job category. Cancer mortality was raised at one quarry due to a significant increase in lung (standardised mortality rate (SMR) 162.0, 95% CI 113.5 to 224.3) and bladder (SMR 366.5, 95% CI 167.6 to 695.7) cancers. Mortality from lung cancer and other causes did not show a trend with cumulative exposure to RCS.Conclusions:This study did not show any consistent relation between RCS exposure (in the absence of other known carcinogens) and the development of lung cancer. This contrasts with a number of studies that have shown positive findings in similar and related industries.
Identifying public water facilities with low spatial variability of disinfection by-products for epidemiological investigations
Authors: Hinckley A F , Bachand A M , Nuckols J R , Reif J S 
Published: June 2005

Background and Aims:Epidemiological studies of disinfection by-products (DBPs) and reproductive outcomes have been hampered by misclassification of exposure. In most epidemiological studies conducted to date, all persons living within the boundaries of a water distribution system have been assigned a common exposure value based on facility-wide averages of trihalomethane (THM) concentrations. Since THMs do not develop uniformly throughout a distribution system, assignment of facility-wide averages may be inappropriate. One approach to mitigate this potential for misclassification is to select communities for epidemiological investigations that are served by distribution systems with consistently low spatial variability of THMs.Methods and Results:A feasibility study was conducted to develop methods for community selection using the Information Collection Rule (ICR) database, assembled by the US Environmental Protection Agency. The ICR database contains quarterly DBP concentrations collected between 1997 and 1998 from the distribution systems of 198 public water facilities with minimum service populations of 100 000 persons. Facilities with low spatial variation of THMs were identified using two methods; 33 facilities were found with low spatial variability based on one or both methods. Because brominated THMs may be important predictors of risk for adverse reproductive outcomes, sites were categorised into three exposure profiles according to proportion of brominated THM species and average TTHM concentration. The correlation between THMs and haloacetic acids (HAAs) in these facilities was evaluated to see whether selection by total trihalomethanes (TTHMs) corresponds to low spatial variability for HAAs. TTHMs were only moderately correlated with HAAs (r = 0.623).Conclusions:Results provide a simple method for a priori selection of sites with low spatial variability from state or national public water facility datasets as a means to reduce exposure misclassification in epidemiological studies of DBPs.