bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leaf respiration is differentially affected by leaf vs. stand‐level night‐time warming
Authors: Griffin Kevin L. , Turnbull Matthew , Murthy Ramesh , Lin Guanghui , Adams John , Farnsworth Blake , Mahato Tilak , Bazin Guerric , Potasnak Mark , Berry Joe A. 
Published: March 2003

AbstractPlant respiration is an important physiological process in the global carbon cycle serving as a major carbon flux from the biosphere to the atmosphere. Respiration is sensitive to temperature providing a link between environmental variability, climate change and the global carbon cycle. We measured leaf respiration in Populus deltoides after manipulating the air temperature surrounding part of a single leaf, and compared this to the temperature response of the same leaves after manipulating the temperature of the stand. The short‐term temperature response of respiration (Q10– change in the respiration rate with a 10 °C increase in leaf temperature) was 1.7 when the leaf temperature was manipulated, but 2.1 when the stand‐level temperature was changed. As a result, total night‐time carbon release during the five‐day experiment was 21% lower when using the Q10 estimates from the tradition leaf manipulation compared to the stand‐level manipulation. We conclude that the temperature response of leaf respiration is related to whole plant carbon and energy demands, and that appropriate experimental procedures are required in examining respiratory CO2 release under variable temperature conditions.
Potential changes in the distributions of latitudinally restricted Australian butterfly species in response to climate change
Authors: Beaumont Linda J. , Hughes Lesley 
Published: March 2003

AbstractThis study assessed potential changes in the distributions of Australian butterfly species in response to global warming. The bioclimatic program, BIOCLIM, was used to determine the current climatic ranges of 77 butterfly species restricted to Australia. We found that the majority of these species had fairly wide climatic ranges in comparison to other taxa, with only 8% of butterfly species having a mean annual temperature range spanning less than 3 °C.The potential changes in the distributions of 24 butterfly species under four climate change scenarios for 2050 were also modelled using BIOCLIM. Results suggested that even species with currently wide climatic ranges may still be vulnerable to climate change; under a very conservative climate change scenario (with a temperature increase of 0.8–1.4 °C by 2050) 88% of species distributions decreased, and 54% of species distributions decreased by at least 20%. Under an extreme scenario (temperature increase of 2.1–3.9 °C by 2050) 92% of species distributions decreased, and 83% of species distributions decreased by at least 50%. Furthermore, the proportion of the current range that was contained within the predicted range decreased from an average of 63% under a very conservative scenario to less than 22% under the most extreme scenario.By assessing the climatic ranges that species are currently exposed to, the extent of potential changes in distributions in response to climate change and details of their life histories, we identified species whose characteristics may make them particularly vulnerable to climate change in the future.
Carbon balance and radiative forcing of Finnish peatlands 1900–2100 – the impact of forestry drainage
Authors: Minkkinen Kari , Korhonen Riitta , Savolainen Ilkka , Laine Jukka 
Published: March 2003

AbstractNatural peatlands accumulate carbon (C) and nitrogen (N). They affect the global climate by binding carbon dioxide (CO2) and releasing methane (CH4) to the atmosphere; in contrast fluxes of nitrous oxide (N2O) in natural peatlands are insignificant. Changes in drainage associated with forestry alter these greenhouse gas (GHG) fluxes and thus the radiative forcing (RF) of peatlands. In this paper, changes in peat and tree stand C stores, GHG fluxes and the consequent RF of Finnish undisturbed and forestry‐drained peatlands are estimated for 1900–2100. The C store in peat is estimated at 5.5 Pg in 1950. The rate of C sequestration into peat has increased from 2.2 Tg a‐‐1 in 1900, when all peatlands were undrained, to 3.6 Tg a‐‐1 at present, when c. 60% of peatlands have been drained for forestry. The C store in tree stands has increased from 60 to 170 Tg during the 20th century. Methane emissions have decreased from an estimated 1.0–0.5 Tg CH4‐‐C a‐‐1, while those of N2O have increased from 0.0003 to 0.005 Tg N2O‐‐N a‐‐1. The altered exchange rates of GHG gases since 1900 have decreased the RF of peatlands in Finland by about 3 mW m‐‐2 from the predrainage situation. This result contradicts the common hypothesis that drainage results in increased C emissions and therefore increased RF of peatlands. The negative radiative forcing due to drainage is caused by increases in CO2 sequestration in peat (‐‐0.5 mW m‐‐2), tree stands and wood products (‐‐0.8 mW m‐‐2), decreases in CH4 emissions from peat to the atmosphere (‐‐1.6 mW m‐‐2), and only a small increase in N2O emissions (+0.1 mW m‐‐2). Although the calculations presented include many uncertainties, the above results are considered qualitatively reliable and may be expected to be valid also for Scandinavian countries and Russia, where most forestry‐drained peatlands occur outside Finland.
Impacts of plant roots on soil CO cycling and soil–atmosphere CO exchange
Authors: KING GARY M. , CROSBY HEIDI 
Published: March 2003

AbstractCarbon monoxide (CO) plays a major role in tropospheric chemical dynamics. Accordingly, global CO budgets have been reasonably well documented. Atmospheric CO consumption by soils contributes significantly to these budgets, with the magnitude of the sink generally considered to reflect a balance between microbial uptake and abiological production. However, assays of live fine roots showed that diverse intact plants produced carbon monoxide at net rates ranging from 2 to 3000 mµg gdw−−1 d−−1. CO production was greater for legumes than nonlegumes, and primarily associated with nodules. Excised roots from woody and herbaceous plants produced CO at comparable rates. CO production rates were similar for roots of intact plants and roots excised from those plants. The magnitude of net CO fluxes from roots was determined in part by the balance between simultaneous production and consumption. Surface sterilization of roots indicated that CO consumption was due, in part, rhizoplane CO‐oxidizing bacteria, but maximum CO consumption rates were typically only a small fraction of net production rates. Assays in a Brazilian agroecosystem indicated that root CO production affects soil–atmosphere CO exchange. Estimates of global CO production rates indicated that roots contribute about 170–260 Tg CO to the soil atmosphere annually, an amount comparable to current estimates of atmospheric CO uptake by soils, and much larger than estimates of net abiological soil CO production.
A cross‐biome comparison of daily light use efficiency for gross primary production
Authors: TURNER DAVID P. , URBANSKI SHAWN , BREMER DALE , WOFSY STEVEN C. , MEYERS TILDEN , GOWER STITH T. , GREGORY MATTHEW 
Published: March 2003

AbstractVegetation light use efficiency is a key physiological parameter at the canopy scale, and at the daily time step is a component of remote sensing algorithms for scaling gross primary production (GPP) and net primary production (NPP) over regional to global domains. For the purposes of calibrating and validating the light use efficiency (εg) algorithms, the components of εg– absorbed photosynthetically active radiation (APAR) and ecosystem GPP – must be measured in a variety of environments. Micrometeorological and mass flux measurements at eddy covariance flux towers can be used to estimate APAR and GPP, and the emerging network of flux tower sites offers the opportunity to investigate spatial and temporal patterns in εg at the daily time step. In this study, we examined the relationship of daily GPP to APAR, and relationships of εg to climatic variables, at four micrometeorological flux tower sites – an agricultural field, a tallgrass prairie, a deciduous forest, and a boreal forest. The relationship of GPP to APAR was close to linear at the tallgrass prairie site but more nearly hyperbolic at the other sites. The sites differed in the mean and range of daily εg, with higher values associated with the agricultural field than the boreal forest. εg decreased with increasing APAR at all sites, a function of mid‐day saturation of GPP and higher εg under overcast conditions. εg was generally not well correlated with vapor pressure deficit or maximum daily temperature. At the agricultural site, a εg decline towards the end of the growing season was associated with a decrease in foliar nitrogen concentration. At the tallgrass prairie site, a decline in εg in August was associated with soil drought. These results support inclusion of parameters for cloudiness and the phenological status of the vegetation, as well as use of biome‐specific parameterization, in operational εg algorithms.
Effects of feeding ensiled kale (Brassica oleracea) on the performance of finishing lambs
Authors: Vipond  , Duncan  , Turner  , Goddyn  , Horgan  
Published: March 2003

The use of forage brassicas, such as kale, in diets of ruminants is typically constrained by the presence of anti‐metabolites that break down in the rumen to cause detrimental effects after absorption including haemolytic anaemia and tissue damage. Ensilage of kale before feeding may provide conditions that favour the degradation of potentially toxic anti‐metabolites, thereby improving the nutritive value of the feed. An experiment was conducted with eighty Scottish Blackface housed lambs, in which four levels of kale silage were used to replace grass silage and in which the forage component comprised around 60% of the finishing diet. Productivity of lambs was not affected other than to increase the killing‐out percentage of the lambs. Glucosinolate concentrations in kale were markedly reduced by the ensiling process. Haematological parameters, such as packed cell volume, haemoglobin concentration and the presence of Heinz−Ehrlich bodies, were not significantly affected by replacing grass silage with kale silage. Similarly, there were no significant effects arising from the dietary treatments on the blood plasma components, gamma‐glutamyl transpeptidase, blood urea nitrogen, tri‐iodothyroxine and thyroxine, which are conventional measures of glucosinolate toxicity.The results indicated that the ensilage of kale reduces its toxicity and hence removes constraints on the maximum inclusion levels in the diet. Also, it was possible to reduce the potential contamination of carcasses with soil by lambs not grazing the crop and thus keeping fleeces clean.
The efficacy of repeated applications of the urease inhibitorN‐(n‐butyl) thiophosphoric triamide for improving the efficiency of urea fertilizer utilization on temperate grassland
Authors: Watson C. J. , Poland P. , Allen M. B. D. 
Published: March 2003

AbstractThe effect ofN‐(n‐butyl) thiophosphoric triamide (nBTPT)‐amended urea on herbage dry‐matter yield and nitrogen offtake by perennial ryegrass (Lolium perenne) was studied in fifteen grassland experiments at two sites in Northern Ireland between 1994 and 1996. The dry‐matter yield and N offtake with applied urea was only significantly lower than that with applied calcium ammonium nitrate (CAN) on four occasions. On these occasions nBTPT increased the yield from the application of urea making it almost as effective as CAN. There was no evidence of any adverse effect on grass production with repeated applications of nBTPT‐amended urea over a 3‐year period and no indication that its efficacy to reduce NH3, loss from ureatreated swards declined when used repeatedly on the same soil.
Safe insertion of trocars and the Veress needle using standard equipment and the 11 security steps
Authors: Semm Kurt , Semm Isolde 
Published: March 2003

ObjectiveTo increase the safety of trocar insertion, bearing in mind that 43% of laparoscopic injuries occur during the first minutes of the procedure, and are linked to the method of entry.DesignThe development of 11 safety tests, all under visual control: (1) palpation of the aorta; (2) needle flow resistance; (3) snap test; (4) hiss test; (5) negative pressure test; (6) aspiration test; (7) ‘quadro’ test; (8) sounding test; (9) ‘Z’‐track incision; (10) trocar insertion under visual control; (11) 360° circumferential view.SettingThe University Hospital for Women in Kiel, Germany.ResultsIn 6000 laparoscopies, only one bowel perforation occurred.ConclusionBlind puncture of the abdominal wall should be proscribed in the next millenium.
Hysteroscopic fallopian tube recanalization using a flexible guide cannula and hydrophilic guide wire
Authors: Allahbadia Gautam N. , Mangeshikar Prashant , Dhungat P. B. Pai , Desai Sadhana K. , Gudi Anil A. , Arya Anup 
Published: March 2003

ObjectiveTo evaluate an innovative and simple procedure of hysteroscopic recanalization of cornual occlusion using a diagnostic hysteroscopic sheath, a Labotect flexible guide cannula and a Terumo hydrophilic guide wire, which were all used under laparoscopic guidance.DesignIn this prospective study, 17 patients with primary or secondary infertility with proven bilateral cornual blockage were scheduled for a recanalization procedure, between June 1995 and October 1998.SettingUniversity‐based teaching hospital and the principal author's private clinic.Subjects and methodsWe combined hysteroscopic cannulation of the proximal fallopian tube using a Labotectcannula with laparoscopic guidance in 17 patients with proximal tubal obstruction which had been diagnosed by hysterosalpingography and confirmed at laparoscopy. This procedure, in addition to being minimally invasive, also accomplishes the objective of causing minimal trauma to the fallopian tube by virtue of the dual hysteroscopic and laparoscopic guidance.Main outcome measuresSuccessful on‐table atraumatic recanalization of blocked fallopian tubes, documented by laparoscopic chromopertubation.ResultsHysteroscopic cannulation could be attempted in 30 tubal ostia and was successfully accomplished in 15 cases. The instances in which we could not cannulate the tubal ostia (two patients) were not failures of cannulation but failures to visualize the internal tubal ostia because of thick endometrium. Four of our patients have conceived following this procedure and have delivered at term.ConclusionHysteroscopic cannulation of the fallopian tube is a safe diagnostic procedure that can be used to identify those patients with true proximal occlusion, and may also serve as a therapeutic procedure in some of these patients. We recommend the use of a depot gonadotrophin‐releasing agonist, such as triptorelin, 10–15 days before attempting this procedure, for easy visualization and access to the internal tubal ostia. The relative simplicity of the procedure means a shorter learning curve for clinicians in training and other beginners, and the results can be consistently reproduced as shown by the 15 successful cases in this study.
Knowledge of HIV/AIDS and emotional adjustment in a cohort of men with haemophilia and HIV infection: final report
Authors: Marsettin E. Pasqual , Ciavarella  , Lobaccaro  , Ghirardini  , Puopolo  , Cultraro  , Morfini  , Rocino  
Published: March 2003

This study presents the final report of a long‐term psychological assessment of men with haemophilia and HIV infection. The knowledge, emotional impact regarding HIV infection and prospective changes over time and the need for psychological support were evaluated.The study group comprised 118 men with haemophilia, 66 HIV seropositive and 52 seronegative, from the Haemophilia Centres in Bari, Florence, Milan and Naples.All subjects performed psychological tests (STAI: state and trait anxiety inventory; SDS: self‐rating depression scale) and completed questionnaires to ascertain their knowledge and the emotional impact of AIDS. After enrolment (1992–93) the assessment was repeated twice over a 2‐year period. A high percentage of subjects in both groups answered the questionnaire on knowledge correctly and, more specifically, all (100%) admitted knowing that sexual intercourse was a risk factor for HIV infection, adding that sexual partners of haemophiliacs with HIV should be regularly tested. The percentage, however, decreased for seropositives who admitted to always using a condom during sexual intercourse (86%) and for those who declared that partners were periodically tested for HIV (60%).The most important feature of the study is that, contrary to predicted expectations, seropositive and seronegative subjects presented the same degree of emotional involvement: there are no statistically significant differences in average scores between groups either on the anxiety or depression scales. Moreover, for certain aspects, seronegatives revealed greater emotional involvement: at baseline evaluation, they felt more fear and unhappiness with statistically significant differences compared to asymptomatics. Furthermore, seronegatives more than seropositives continue to feel reluctance towards infusion and avoid blood products after learning of AIDS. These results emphasize the importance of paying due attention to the emotional status of seronegatives. Their reluctance towards the use of blood products (despite present safety) is a very important issue for the possible consequences of treatment with the risk of worsening the clinical condition. In conclusion, we believe that counselling on HIV infection/AIDS needs to address every person with haemophilia regardless of HIV status.
Changes in hepatitis B serologic titers in HIV+ and HIV– children with haemophilia
Authors: Kisker  , Mahoney  , Arkin  , Maeder  , Donfield  , Evatt  ,   THE HEMOPHILIA GROWTH DEVELOPMENT STUDY
Published: March 2003

This longitudinal study examines differences in hepatitis B immune titres in children and adolescents with haemophilia to determine if they are dependent on how immunity was acquired (vaccination or natural infection), and whether they are related to the child’s HIV status and/or are influenced by HIV disease progression.Serologic titres (HBcAb, HBsAb) and HBsAg were measured prospectively at baseline, and at years 1, 2 and 3 of follow‐up in 126 HIV– and 207 HIV+ children and adolescents with haemophilia. Analyses were performed to assess the impact of HIV status on the measured titres, and for HIV+ subjects to examine the association with CD4+ lymphocyte counts and p24 antigen status.The results show that HIV+ children were more likely than HIV– children to lose vaccine‐induced immunity as indicated by the loss of HBsAb. There was an increased risk of losing HBsAb with higher CD4+ counts and younger age. Re‐immunization was not successful in seven of eight HIV+ children. Two subjects (one HIV+ , one HIV–) entered the study HBsAg− but became HBsAg+ over the course of follow‐up. Seven HIV+ subjects lost natural immunity as indicated by the loss of HBcAb. The loss of either HBsAb or HBcAb in HIV– subjects was negligible to absent.In conclusion, because of the loss of immunity in HIV+ children the viral safety of factor replacement concentrates for these children is an important consideration. HIV– children rarely lose immunity, therefore frequent measures of HBsAb are not necessary.
Monitoring and modelling open savannas using multisource information: analyses of Kalahari studies
Authors: Dougill Andrew , Trodd Nigel 
Published: March 2003

SummaryIn the Kalahari of Botswana, as in many other open savannas, the main ecological change following cattle‐based agricultural intensification is one of grass removal and bush encroachment. Changes to vegetation communities in Kalahari rangelands have been expressed in terms of a state‐and‐transition model. However, there remain uncertainties as to the mechanisms and conditions for ecological change. In part, this is due to previous (inadequate) spatial and temporal scales of data collection. This paper describes the results of ongoing ecological studies in the Makoba ranches and analyses the contribution that fine‐scale ground‐based surveys and interpretation of Earth observation data can make to reducing uncertainties in state‐and‐transition models. This detailed case study provides a mechanism for evaluating the role of multi‐source information for monitoring and modelling open savannas.
Global land cover characterization from satellite data: from research to operational implementation?
Authors: Defries R. S. , Townshend J. R. G. 
Published: March 2003

SummarySatellite data provide the basis for geographically referenced global land cover characterization that is internally consistent, repeatable over time, and potentially more reliable than ground‐based sources. During the last 20 years considerable research efforts have been devoted to the extraction of land cover information from these data. Only during the last few years have these methods begun to be applied in operational contexts. Such applications have thus far primarily addressed key global change issues such as the global carbon balance. Examples of the successful quasi‐operational implementation of remote sensing include NASA's Humid Tropical Landsat Pathfinder project, where high resolution data are being used at subcontinental scales to measure change in the areal extent of tropical rain forests throughout the world, and the Tropical Ecosystem Environment observation by Satellite (TREES) project to assess forest cover in the tropics. At coarser resolutions, a number of land cover products suitable for incorporation in global and regional models have been developed. Alternatives to traditional land cover classifications have also been developed to describe gradients and mosaics in the vegetation more realistically. These land cover products offer the possibility for applications in ecological and human dimensions research at regional and global scales, as well as for implementation of international agreements that require land cover information. Recently launched and future satellites will carry sensors that provide data with greatly improved capabilities for land cover characterization and advancements in computing environments make it feasible to take advantage of these new data. However, several challenges must be overcome in making a transition from research to operational land cover monitoring, including automation of methods to analyse the satellite data, more effective techniques for validation, and assurance of long‐term continuity in the availability of satellite measurements.