bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potassium limits potential growth of bog vegetation under elevated atmospheric CO2and N deposition
Authors: HOOSBEEK MARCEL R. , VAN BREEMEN NICO , VASANDER HARRI , BUTTLER ALEXANDRE , BERENDSE FRANK 
Published: March 2003

AbstractThe free air carbon dioxide enrichment (FACE) and N deposition experiments on four ombrotrophic bogs in Finland, Sweden, the Netherlands and Switzerland, revealed that after three years of treatment: (1) elevated atmospheric CO2concentration had no significant effect on the biomass growth ofSphagnumand vascular species; and (2) increased N deposition reduced Sphagnum growth, because it increased the cover of vascular plants and the tall mossPolytrichum strictum, while vascular plant biomass growth was not affected. This paper focuses on water chemistry, plant nutrient content, and litter decomposition rates. Potassium limitation, or low supply of K and P, may have prevented a significant increase ofSphagnumgrowth under elevated CO2and N deposition. Vascular plant growth under elevated CO2and N deposition was also limited by K, or by K in combination with P or N (N in CO2experiment). Elevated CO2and N deposition had no effect on decomposition rates ofSphagnumand vascular plant litter. Aside from a possible effect of N deposition on light competition between species, we expect that elevated atmospheric CO2and N deposition concentrations will not affectSphagnumand vascular plant growth in bogs of north‐west Europe due to K‐, or K in combination with N‐ or P‐, limited growth. For the same reason we expect no effect of elevated CO2and N deposition on litter decomposition. Net primary production of raised ombrotrophic bogs that are at or close to steady state, is regulated by input of nutrients through atmospheric deposition. Therefore, we hypothesize that the expected increase of plant growth under elevated CO2and N deposition is diminished by current levels of K (and to some extent P and N) in atmospheric deposition.
Effects of aggregated classifications of forest composition on estimates of evapotranspiration in a northern Wisconsin forest
Authors: MACKAY D. S. , AHL D. E. , EWERS B. E. , GOWER S. T. , BURROWS S. N. , SAMANTA S. , DAVIS K. J. 
Published: March 2003

AbstractForest management presents challenges to accurate prediction of water and carbon exchange between the land surface and atmosphere, due to its alteration of forest structure and composition. We examined how forest species types in northern Wisconsin affect landscape scale water fluxes predicted from models driven by remotely sensed forest classification. A site‐specific classification was developed for the study site. Using this information and a digital soils database produced for the site we identified four key forest stand types: red pine, northern hardwoods, aspen, and forested wetland. Within these stand types, 64 trees representing 7 species were continuously monitored with sap flux sensors. Scaled stand‐level transpiration from sap flux was combined with a two‐source soil evaporation model and then applied over a 2.5 km × 3.0 km area around the WLEF AmeriFlux tower (Park Falls, Wisconsin) to estimate evapotranspiration. Water flux data at the tower was used as a check against these estimates. Then, experiments were conducted to determine the effects of aggregating vegetation types to International Geosphere– Biosphere Program (IGBP) level on water flux predictions. Taxonomic aggregation resulting in loss of species level information significantly altered landscape water flux predictions. However, daily water fluxes were not significantly affected by spatial aggregation when forested wetland evaporation was included. The results demonstrate the importance of aspen, which has a higher transpiration rate per unit leaf area than other forest species. However, more significant uncertainty results from not including forested wetland with its high rates of evaporation during wet summers.
Modelling carbon balances of coastal arctic tundra under changing climate
Authors: Grant Robert F. , Oechel Walter C. , Ping Chien‐Lu 
Published: March 2003

AbstractRising air temperatures are believed to be hastening heterotrophic respiration (Rh) in arctic tundra ecosystems, which could lead to substantial losses of soil carbon (C). In order to improve confidence in predicting the likelihood of such loss, the comprehensive ecosystem model ecosys was first tested with carbon dioxide (CO2) fluxes measured over a tundra soil in a growth chamber under various temperatures and soil‐water contents (θ). The model was then tested with CO2 and energy fluxes measured over a coastal arctic tundra near Barrow, Alaska, under a range of weather conditions during 1998–1999. A rise in growth chamber temperature from 7 to 15 °C caused large, but commensurate, rises in respiration and CO2 fixation, and so no significant effect on net CO2 exchange was modelled or measured. An increase in growth chamber θ from field capacity to saturation caused substantial reductions in respiration but not in CO2 fixation, and so an increase in net CO2 exchange was modelled and measured. Long daylengths over the coastal tundra at Barrow caused an almost continuous C sink to be modelled and measured during most of July (2–4 g C m−2 d−1), but shortening daylengths and declining air temperatures caused a C source to be modelled and measured by early September (∼1 g C m−2 d−1). At an annual time scale, the coastal tundra was modelled to be a small C sink (4 g C m−2 y−1) during 1998 when average air temperatures were 4 °C above normal, and a larger C sink (16 g C m−2 y−1) during 1999 when air temperatures were close to long‐term normals. During 100 years under rising atmospheric CO2 concentration (Ca), air temperature and precipitation driven by the IS92a emissions scenario, modelled Rh rose commensurately with net primary productivity (NPP) under both current and elevated rates of atmospheric nitrogen (N) deposition, so that changes in soil C remained small. However, methane (CH4) emissions were predicted to rise substantially in coastal tundra with IS92a‐driven climate change (from ∼20 to ∼40 g C m−2 y−1), causing a substantial increase in the emission of CO2 equivalents. If the rate of temperature increase hypothesized in the IS92a emissions scenario had been raised by 50%, substantial losses of soil C (∼1 kg C m−2) would have been modelled after 100 years, including additional emissions of CH4.
Options for mitigating methane emission from a permanently flooded rice field
Authors: Cai Zucong , Tsuruta Haruo , Gao Ming , Xu Hua , Wei Chaofu 
Published: March 2003

AbstractPermanently flooded rice fields, widely distributed in south and south‐west China, emit more CH4 than those drained in the winter crop season. For understanding CH4 emissions from permanently flooded rice fields and developing mitigation options, CH4 emission was measured year‐round for 6 years from 1995 to 2000, in a permanently flooded rice field in Chongqing, China, where two cultivations with four treatments were prepared as follows: plain‐cultivation, summer rice crop and winter fallow with floodwater layer annually (convention, Ch‐FF), and winter upland crop under drained conditions (Ch‐Wheat); ridge‐cultivation without tillage, summer rice and winter fallow with floodwater layer annually (Ch‐FFR), and winter upland crop under drained conditions (Ch‐RW), respectively. On a 6‐year average, compared to the treatments with floodwater in the winter crop season, the CH4 flux during rice‐growing period from the treatments draining floodwater and planting winter crop was reduced by 42% in plain‐cultivation and by 13% in ridge‐cultivation (P < 0.05), respectively. The reduction of annual CH4 emission reached 68 and 48%, respectively. Compared to plain‐cultivation (Ch‐FF), ridge‐cultivation (Ch‐FFR) reduced annual CH4 emission by 33%, and which was mainly occurred in the winter crop season. These results indicate that draining floodwater layer for winter upland crop growth was not only able to prevent CH4 emission from permanently flooded paddy soils directly in the winter crop season, but also to reduce CH4 emission substantially during the following rice‐growing period. As an alternative to the completely drainage of floodwater layer in the winter crop season, ridge‐cultivation could also significantly mitigate CH4 emissions from permanently flooded rice fields.
Seasonal patterns of soil CO2 efflux and soil air CO2 concentration in a Scots pine forest: comparison of two chamber techniques
Authors: PUMPANEN JUKKA , ILVESNIEMI HANNU , PERÄMÄKi MARTTI , HARI PERTTI 
Published: March 2003

AbstractA non‐vented non‐steady state flow‐through chamber and a non‐vented non‐steady state non‐flow‐through chamber technique were used to measure CO2 efflux of a young Scots pine forest on a fertile till soil in southern Finland. Soil temperature, soil moisture and soil CO2 concentration were measured concurrently with CO2 efflux for two and a half successive years. The CO2 efflux showed a seasonal pattern, effluxes ranging from low 0.0–0.1 g CO2 m−2 h−1 in winter to peak values of 2.3 g CO2 m−2 h−1 occurring in late June and in July. The daily average effluxes in July measured by flow through chambers were 1.23 and 0.98 g CO2 m−2 h−1 in 1998 and 1999, respectively. The annual accumulated CO2 efflux was 3117 and 3326 g CO2 m−2 in 1998 and 1999, respectively. The spatial variation in CO2 efflux was high (CV 0.18–0.45) and increased with increasing efflux. Soil air CO2 concentration showed similar seasonal pattern the peak concentrations occurring in July–August. The CO2 concentrations ranged from 580 to 780 µmol mol−1 in the humus layer to 13 620–14 470 µmol mol−1 in the C‐horizon. In winter the soil air CO2 concentrations were lower, especially in deeper soil layers. Drought decreased CO2 efflux and soil air CO2 concentration. The in situ comparison on forest soil between the chamber methods showed the non‐flow‐through chamber to give ∼∼50% lower efflux values than that of the flow‐through chamber. When calibrated against known CO2 efflux ranging from 0.4 to 0.8 g CO2 m−2 h−1 generated with a diffusion box method developed by Widén and Lindroth [Acta Universitatis Agriculturae Suecia Silvestria, 2001], the flow‐through chamber gave equal effluxes at the lower end of the calibration range, but overestimated high effluxes by 20%. Non‐flow‐through chamber underestimated the CO2 efflux by 30%.
Land use induced changes of organic carbon storage in soils of China
Authors: WU HAIBIN , GUO ZHENGTANG , PENG CHANGHUI 
Published: March 2003

AbstractUsing the data compiled from China's second national soil survey and an improved method of soil carbon bulk density, we have estimated the changes of soil organic carbon due to land use, and compared the spatial distribution and storage of soil organic carbon (SOC) in cultivated soils and noncultivated soils in China. The results reveal that ∼ 57% of the cultivated soil subgroups (∼ 31% of the total soil surface) have experienced a significant carbon loss, ranging from 40% to 10% relative to their noncultivated counterparts. The most significant carbon loss is observed for the non‐irrigated soils (dry farmland) within a semiarid/semihumid belt from northeastern to southwestern China, with the maximum loss occurring in northeast China. On the contrary, SOC has increased in the paddy and irrigated soils in northwest China. No significant change is observed for forest soils in southern China, grassland and desert soils in northwest China, as well as irrigated soils in eastern China. The SOC storage and density under noncultivated conditions in China are estimated to ∼ 77.4 Pg (1015 g) and ∼ 8.8 kg C m−2, respectively, compared to a SOC storage of ∼ 70.3 Pg and an average SOC density of ∼ 8.0 kg C m−2 under the present‐day conditions. This suggests a loss of ∼ 7.1 Pg SOC and a decrease of ∼ 0.8 kg C m−2 SOC density due to increasing human activities, in which the loss in organic horizons has contributed to ∼ 77%. This total loss of SOC in China induced by land use represents ∼ 9.5% of the world's SOC decrease. This amount is equivalent to ∼ 3.5 ppmv of the atmospheric CO2 increase. Since ∼ 78% of the currently cultivated soils in China have been degraded to a low/medium productivities and are responsible for most of the SOC loss, an improved land management, such as the development of irrigated and paddy land uses, would have a considerable potential in restoring the SOC storage. Assuming a restoration of ∼ 50% of the lost SOC during the next 20–50 years, the soils in China would absorb ∼ 3.5 Pg of carbon from the atmosphere.
The effect of some acid‐based additives applied to wet grass crops under various ensiling conditions
Authors: Randby Å. T. 
Published: March 2003

Some acid‐based silage additives, which are less corrosive and easier to handle than Formic acid 85% (FA), were evaluated in a laboratory‐scale silage experiment. These were Foraform (645 g kg–1 formic acid, 60 g kg–1 NH3), Ensimax [213 g kg–1 formic acid, 200 g kg–1 acetic acid, 190 g kg–1 of dry matter from wood pulp liquor with a high concentration of lignosulphonates (WPL)], and a modified version of Ensimax with a higher proportion of formic acid and a lower proportion of acetic acid. Each single ingredient, and all combinations of ingredients in the original Ensimax, were studied when applied in the quantities they make up in the additive. Untreated silage was used as a negative control and FA as a positive control. The additives were assessed using three different crops and by sealing the silos immediately after filling or after a 24 h delay. Both the full and half of the recommended application rates of the additives and of the single ingredients of Ensimax were studied.No significant differences were found between FA and Foraform when applied at 3 and 4 l t–1, respectively, which provided the crop with the same dose of pure formic acid. Inclusion of WPL in Ensimax did not influence silage fermentation, i.e. the effect of Ensimax could be ascribed to the effect of formic plus acetic acid alone. Compared with Ensimax, the modified version, in which 148 g kg–1 of formic acid was substituted for 150 g kg–1 of acetic acid, clearly improved fermentation in terms of increased concentration of true protein, reduced fermentation of acetic and propionic acid, and reduced ammonia value and pH. When the silos were sealed immediately, sugar concentrations in the silage correlated positively with the application rate of acids, whereas no such relationship was found when the sealing was delayed for 24 h. No consistent relationship was found between the application rate of acids and ethanol concentrations in the silage.Easy‐to‐handle acidic additives like Foraform and Ensimax may replace FA when applied according to their molar concentration of acids. This means that 4·0 l t–1 of Foraform and 7·3 l t–1 of Ensimax are equivalent to 3 l t–1 of FA.
A randomized study comparing levonorgestrel intrauterine system (LNG IUS) and transcervical resection of the endometrium (TCRE) in the treatment of menorrhagia: preliminary results
Authors: Kittelsen Nina , Istre Olav 
Published: March 2003

ObjectiveTo identify the effect of the levonorgestrel coil (Mirena; LNG IUS) vs. transcervical resection of the endometrium (TCRE) for treatment of menorrhagia.DesignA randomized study of 60 patients performed at a gynaecological clinic specializing in operative hysteroscopy.Results24 patients in the LNG IUS group and 29 patients in the TCRE group completed 20 months of follow up. In the TCRE group one patient refused to continue after the result of randomization. Reasons for discontinuation in the LNG IUS group included abdominal pain (2), acne (1) and bleeding or continuous spotting (3). The bleeding intensity was assessed using the PBAC score and was reduced in both groups, from 418 to 42 in the LNG IUS group, and from 378 to 6.6 in the TCRE group.ConclusionBoth methods have a dramatic effect on bleeding intensity and furthermore the LNG IUS is reversible and has no operative hazards or side‐effects.
Trocar injuries during laparoscopic gynaecological surgery. Report from the French Society of Gynaecological Laparoscopy
Authors: Marret, Henri , Harchaoui, Yahia , Chapron, Charles , Lansac Jacques , Pierre Fabrice 
Published: March 2003

ObjectiveTo review laparoscopic complications resulting from trocar insertions and to define their risk factors.MethodsThe French register of laparoscopic complications was reviewed for this study.ResultsA total of 47 complications due to trocar insertions were recorded between 1994 and 1997: 29 vascular injuries (18 parietal vascular injuries), 12 bowel injuries, three bladder perforations and three incisional hernias were noted in this survey. Regardless of the operator, the indication for laparoscopy or the type of trocar used, some patients seem to be more at risk for complications at laparoscopic surgery: 72% of the studied group had undergone previous abdominal surgery and 54% were overweight; and in 30% infringement of the recognized safety rules for trocar insertion was the main cause of injury. Laparotomy was needed for these complications in 64% of all cases, and in 90% of cases if vascular injuries of the abdominal wall were not included. Laparotomy for repair of the injury was delayed in 21% of cases, and it was done by the same surgeon who performed the laparoscopic procedure in 83%.ConclusionsTo reduce the risk of trocar injuries, surgeons must be careful and must respect the rules for safe trocar insertion, particularly when there is a history of previous surgery. ‘Open laparoscopy’ may be useful in facilitating a laparoscopic procedure which is as safe as possible, but the technique is not yet validated. Laparoscopists must inform the patient concerning the risk of laparotomy becoming necessary should trocar injury occur. Other clinicians should participate in recording complications in registers, similar to that of the French Society of Gynaecological Laparoscopy, to accumulate valuable information concerning trocar injuries.
Diagnosis and treatment of abnormal uterine bleeding in postmenopausal patients using hormone replacement therapy
Authors: Maia Jr Hugo , Maltez Amelia , Oliveira Maita , Calmon Luis C. , Coutinho Elsimar M. 
Published: March 2003

ObjectiveTo investigate the cause of uterine bleeding in menopausal patients using hormone replacement therapy (HRT), and the efficacy of resectoscopic surgery for treatment of irregular vaginal bleeding caused by benign uterine pathology in such patients.DesignRetrospective case series.SettingEndoscopy unit of a private urban hospital.Subjects143 patients receiving HRT and with irregular vaginal bleeding, examined between January 1994 and December 1997.InterventionsAll the patients were evaluated using transvaginal sonography, hysteroscopy and endometrial biopsies. A total of 87 patients with polyps, myomas or an atrophic uterine cavity underwent polypectomy (n = 64) and myomectomy (n = 19) in association with endometrial resection (n = 87).ResultsEndometrial polyps and submucous myomas were the most frequent cause of uterine bleeding in postmenopausal women using HRT. These conditions could be treated effectively using the resectoscope. The failure rate of resectoscopic surgery for focal lesions in patients receiving HRT was 6%. Adenomyosis and recurrence of endometrial polyps were the most frequent reasons for treatment failure and resumption of vaginal bleeding.ConclusionUterine bleeding caused by endometrial polyps and submucous myomas in menopausal patients using HRT can be effectively treated with the resectoscope.
Implantation endometrioma at port site after laparoscopic abdominal supracervical hysterectomy
Authors: Wilson Hayley , Shaxted Edward J. 
Published: March 2003

ObjectiveTo report three instances of implantation endometriomas occurring after laparoscopic subtotal hysterectomy.SubjectsThree patients who developed implantation endometriomas at the site of insertion of the morcellator used in laparoscopic subtotal hysterectomy are described. At one hospital this occurred in two patients out of 54, giving an incidence of 4%.ConclusionImplantation endometriosis may be a risk associated with morcellation of the uterus at laparoscopic subtotal hysterectomy.
Outpatient hysteroscopy: indications and hysteroscopic findings in pre‐ and postmenopausal patients
Authors: Decloedt Jan F. , Fenton David W. 
Published: March 2003

ObjectivesWe present a large series of outpatient hysteroscopies in order to assess the feasibility of the procedure, the incidence of abnormal findings in pre‐ and postmenopausal patients and to define a lower age limit for hysteroscopic investigation of patients presenting with abnormal uterine bleeding (AUB).SettingThe Endoscopy Clinic of the Rotherham District General Hospital, Rotherham, UK.Subjects665 patients with a mean age of 47  years. Only patients presenting with abnormal uterine bleeding were included in the study.Interventions673 outpatient hysteroscopies were carried out; 469 (69%) procedures were done in premenopausal and 204 (31%) in postmenopausal patients. All procedures were done under local anaesthesia with 4‐mm rigid hysteroscopes with a 30° objective, using video endoscopy.ResultsThe failure rate was only 6%, i.e. 2.4% in the premenopausal and 11% in the postmenopausal group. The incidence of intrauterine pathology was similar in those patients presenting with intermenstrual bleeding (33%), those presenting with postcoital bleeding (39%), and in those over the age of 40 who presented with menorrhagia (32%). In younger patients (<40 years) with menorrhagia abnormal hysteroscopic findings were seen in 21%, but these were found in only 4% of patients under the age of 30. The lesions in the patients under the age of 40 were mainly uterine fibroids, which can be easily missed using traditional endometrial sampling alone. Uterine fibroids seem to be the commonest lesion in premenopausal patients. Endometrial polyps and endometrial cancer have a peak incidence in patients over the age of 50.ConclusionsOutpatient hysteroscopy is a feasible technique in pre‐ and postmenopausal patients. The high incidence of pathology in post‐ and premenopausal patients with abnormal uterine bleeding justifies its use in all patients presenting with postmenopausal, intermenstrual and postcoital bleeding, and in patients with menorrhagia over the age of 30.
‘Classic’ laparoscopic entry in a university hospital: a series of 8324 cases
Authors: Dubuisson Jean Bernard , Chapron Charles , Decuypère Fouzia , De Spirlet Marina 
Published: March 2003

ObjectiveTo evaluate the complications of ‘classic’ laparoscopic entry in a university tertiary care centre.DesignAn analysis of the complications of classic laparoscopic entry for diagnostic and operative laparoscopies. We considered a consecutive series of 8324 cases with the same entry technique: CO2 insufflation, followed by insertion of the umbilical trocar and subsequent placement of accessory trocars under direct vizualization.SubjectsBetween November 1 1992 and December 31 1998, 8324 patients underwent laparoscopies. The 978 diagnostic laparoscopies (11.75%) and 7346 operative laparoscopies (88.25%) were performed by 14 experienced gynaecological surgeons or by trained surgeons under the supervision of one of the experienced surgeons.Main outcome measuresPeri‐ and postoperative complications of laparoscopic entry were assessed and analysed.ResultsLaparoscopic entry complications occured in 10 cases out of 8324 laparoscopies (0.12%). These included six vascular injuries, three bowel perforations and one bladder complication. No death occurred and no blood transfusions were required. No adverse consequences were observed in five cases. A laparotomy was performed in four cases and in one instance the laparotomy was delayed.ConclusionThe complication rate of classic laparoscopic entry was quite low in our experience. These results suggest that no modifications to the technique for classic laparoscopic entry are needed.