bluuebunny/crossref_metadata_2025 huggingface dataset:
Severe drought effects on ecosystem CO2 and H2O fluxes at three Mediterranean evergreen sites: revision of current hypotheses?
Authors: Reichstein Markus , Tenhunen John D. , Roupsard Olivier , Ourcival Jean‐marc , Rambal Serge , Miglietta Franco , Peressotti Alessandro , Pecchiari Marco , Tirone Giampiero , Valentini Riccardo
Published: March 2003

Eddy covariance and sapflow data from three Mediterranean ecosystems were analysed via top‐down approaches in conjunction with a mechanistic ecosystem gas‐exchange model to test current assumptions about drought effects on ecosystem respiration and canopy CO2/H2O exchange. The three sites include two nearly monospecific Quercus ilex L. forests – one on karstic limestone (Puéchabon), the other on fluvial sand with access to ground water (Castelporziano) – and a typical mixed macchia on limestone (Arca di Noè). Estimates of ecosystem respiration were derived from light response curves of net ecosystem CO2 exchange. Subsequently, values of ecosystem gross carbon uptake were computed from eddy covariance CO2 fluxes and estimates of ecosystem respiration as a function of soil temperature and moisture. Bulk canopy conductance was calculated by inversion of the Penman‐Monteith equation. In a top‐down analysis, it was shown that all three sites exhibit similar behaviour in terms of their overall response to drought. In contrast to common assumptions, at all sites ecosystem respiration revealed a decreasing temperature sensitivity (Q10) in response to drought. Soil temperature and soil water content explained 70–80% of the seasonal variability of ecosystem respiration. During the drought, light‐saturated ecosystem gross carbon uptake and day‐time averaged canopy conductance declined by up to 90%. These changes were closely related to soil water content. Ecosystem water‐use efficiency of gross carbon uptake decreased during the drought, regardless whether evapotranspiration from eddy covariance or transpiration from sapflow had been used for the calculation. We evidence that this clearly contrasts current models of canopy function which predict increasing ecosystem water‐use efficiency (WUE) during the drought. Four potential explanations to those results were identified (patchy stomatal closure, changes in physiological capacities of photosynthesis, decreases in mesophyll conductance for CO2, and photoinhibition), which will be tested in a forthcoming paper. It is suggested to incorporate the new findings into current biogeochemical models after further testing as this will improve estimates of climate change effects on (semi)arid ecosystems' carbon balances.
Contrasting soil respiration in young and old‐growth ponderosa pine forests
Authors: IRVINE J. , LAW B. E.
Published: March 2003

Three years of fully automated and manual measurements of soil CO2 efflux, soil moisture and temperature were used to explore the diel, seasonal and inter‐annual patterns of soil efflux in an old‐growth (250‐year‐old, O site) and recently regenerating (14‐year‐old, Y site) ponderosa pine forest in central Oregon. The data were used in conjunction with empirical models to determine which variables could be used to predict soil efflux in forests of contrasting ages and disturbance histories. Both stands experienced similar meteorological conditions with moderately cold wet winters and hot dry summers. Soil CO2 efflux at both sites showed large inter‐annual variability that could be attributed to soil moisture availability in the deeper soil horizons (O site) and the quantity of summer rainfall (Y site). Seasonal patterns of soil CO2 efflux at the O site showed a strong positive correlation between diel mean soil CO2 efflux and soil temperature at 64 cm depth whereas diel mean soil efflux at the Y site declined before maximum soil temperature occurred during summer drought. The use of diel mean soil temperature and soil water potential inferred from predawn foliage water potential measurements could account for 80% of the variance of diel mean soil efflux across 3 years at both sites, however, the functional shape of the soil water potential constraint was site‐specific. Based on the similarity of the decomposition rates of litter and fine roots between sites, but greater productivity and amount of fine litter detritus available for decomposition at the O site, we would expect higher rates of soil CO2 efflux at the O site. However, annual rates were only higher at the O site in one of the 3 years (597 ± 45 vs. 427 ± 80 g C m−2). Seasonal patterns of soil efflux at both sites showed influences of soil water limitations that were also reflected in patterns of canopy stomatal conductance, suggesting strong linkages between above and below ground processes.
Species control variation in litter decomposition in a pine forest exposed to elevated CO2
Authors: FINZI ADRIEN C. , SCHLESINGER WILLIAM H.
Published: March 2003

Net primary production and the flux of dry matter and nutrients from vegetation to soils has increased following four years of exposure to elevated CO2in a southern pine forest in NC, USA. This has increased the demand for nutrients to support enhanced rates of NPP and altered the conditions for litter decomposition on the forest floor. We quantified the chemistry and decomposition dynamics of leaf litter produced by five of the most abundant tree species in this ecosystem during the third and fourth growing seasons under elevated CO2. The objectives of this study were to determine (i) if there were systemic or species‐specific changes in leaf litter chemistry associated with a sustained enhancement of plant growth under elevated CO2; and (ii) whether the process of litter decomposition was altered by increased inputs of energy and nutrients to the forest floor in the plots under elevated CO2. Leaf litter chemistry, including various C fractions and N concentration, was virtually unchanged by elevated CO2. With few exceptions, plant litter produced under elevated CO2lost mass or N at the same relative rate as that produced under ambient CO2. The relationship between initial litter chemistry and decomposition was not altered by elevated CO2. The greater forest floor mass and nutrient content in the plots under elevated CO2had no consistent or long‐term effect on litter decomposition. Thus, we found no evidence that plant and microbial processes under elevated CO2resulted in systemic changes in mass loss or N dynamics during decomposition. In contrast to the limited effects of elevated CO2on litter chemistry and decomposition, there were large differences among species in initial litter chemistry, mass loss and N dynamics during decomposition. If the species composition of this forest community is altered by elevated CO2, the indirect effect of a change in species composition will exert greater control over the long‐term rate of nutrient cycling than the direct effect of elevated CO2on litter chemistry and decomposition dynamics alone.
East Atlantic teleconnection pattern and the decline of a common arctiid moth
Authors: Conrad Kelvin F. , Woiwod Ian P. , Perry Joe N.
Published: March 2003

Teleconnection patterns are large‐scale atmospheric circulation systems and variation in them is often associated with impacts on climate and weather over broad areas. Arctia caja L. is a well‐known, widespread and charismatic tiger moth. In recent decades, the abundance of A. caja in UK has fallen abruptly. The annual abundance of A. caja in UK is known to be affected adversely by wet winter weather and warm spring temperatures. We examined A. caja population dynamics from 1968 to 1999 for weather and climatological effects. Population growth rate displayed endogenous effects of abundance in the previous two seasons. Accounting for this, growth rate in the present season was still affected significantly by winter precipitation and spring temperature. Annual abundance of A. caja was inversely related to winter East Atlantic teleconnection pattern (winter EA index) and annual population growth rate was inversely related to winter EA in the present and previous two seasons. An index of the North Atlantic Oscillation (NAO), commonly used as an indicator of winter climate in northern Europe, did not show a significant relationship with growth rate. We noted, for the first time, that the winter EA index has increased steadily over the past five decades. The model presented here therefore implies a further decline of A. caja population growth rates and abundance in the future. This is the first demonstration of a relationship between EA and population dynamics and indicates the EA and other lesser‐known teleconnection patterns may prove useful in modeling the ecological effects of climate change.
Climate change and fitness components of a migratory bird breeding in the Mediterranean region
Authors: SANZ JUAN JOSÉ , POTTI JAIME , MORENO JUAN , MERINO SANTIAGO , FRÍAs OSCAR
Published: March 2003

The increase in spring temperatures in temperate regions over the last two decades has led to an advancing spring phenology, and most resident birds have responded to it by advancing their onset of breeding. The pied flycatcher (Ficedula hypoleuca) is a long‐distance migrant bird with a relatively late onset of breeding with respect to both resident birds and spring phenology in Europe. In the present correlational study, we show that some fitness components of pied flycatchers are suffering from climate change in two of the southernmost European breeding populations. In both montane study areas, temperature during May increased between 1980 and 2000 and an advancement of oak leafing was detected by using the normalized difference vegetation index (NDVI) to assess tree phenology. This might result in an advancement of the peak in availability of caterpillars, the main prey during the nestling stage. Over the past 18 yr, the time of egg laying and clutch size of pied flycatchers were not affected by the increase in spring temperatures in these Mediterranean populations. However, this increase seems to have an adverse effect on the reproductive output of pied flycatchers over the same period. Our data suggest that the mismatch between the timing of peak food supply and nestling demand caused by recent climate change might result in a reduction of parental energy expenditure that is reflected in a reduction of nestling growth and survival of fledged young in our study populations. The data seem to indicate that the breeding season has not shifted and it is the environment that has shifted away from the timing of the pied flycatcher breeding season. Mediterranean pied flycatchers were not able to advance their onset of breeding, probably, because they are constrained by their late arrival date and their restricted high altitude breeding habitat selection near the southern border of their range.
The chemical composition, digestibility and energy value of fermented and urea‐treated whole crop wheat harvested at three stages of maturity
Authors: Adesogan A. T. , Owen E. , Givens D. I.
Published: March 2003

The metabolizable energy (ME) content, digestibility in vivo and chemical composition of fermented and urea‐treated whole crop wheat (WCW) forage harvested were measured at different maturities. Over 2 years, twenty‐four wheat forages (cv. Slepjner, Hussar and Cadenza) were harvested at 376, 516 and 632 g dry matter (DM) kg−1 in Year 1 and 341, 467 and 544 g DM kg−1 in Year 2 (Cuts 1, 2 and 3 respectively). Forages were conserved in 200−‐ι barrels with or without a formic acid‐based additive and with urea in Cuts 2 and 3 (20 or 40 g kg−1 DM). Chemical compositions, digestibility in vivo and energy losses in faeces, urine and methane were measured in wethers fed 12 g DM kg−1 live weight. Respective ranges in pH, crude protein, water‐soluble carbohydrates, starch and neutral detergent fibre plus amylase (NDFA) contents were 3·8–8·5, 89–394, 2–43, 23–424 and 306–655 g kg−1 DM. ME content, digestible organic matter content (DOMD) and digestibilities of starch and NDFA ranged between 8·4 and 15·7 MJ kg−1 DM, 558 and 708 g kg−1 DM, 0·901 and 0·999 and 0·362 and 0·693 respectively. Predicted methane energy losses were poorly correlated with measured values (r2 < 0·45) in both years, but this accounted for less than 0.1 MJ ME kg−1 DM. Significant (P < 0.05) effects of maturity on the ME/DOMD ratio were observed and ascribed to differences in the extent of fermentation. Therefore, treatment application and maturity exert considerable influence on the ME content of WCW.
Prediction of the digestibility of the diet of horses: evaluation of faecal indices
Authors: Mésochina P. , Martin‐Rosset W. , Peyraud J.‐L. , Duncan P. , Micol D. , Boulot S.
Published: March 2003

Data from in vivo digestibility trial with four to six horses fed twenty‐seven forage‐based diets are used to calculate prediction equations for the digestibility of dry and organic matter, based on the crude ash (CA), crude protein (CP) and crude fibre (CF) contents of diets and faeces. The most precise prediction of dry‐matter digestibility (r.s.d. = 0.032, R2= 0.80) was derived from a multiple regression including faecal (CP, CF) and dietary parameters (CF). Among faecal parameters, CP was the best single predictor of both digestibility (r.s.d) = 0.040, r2= 0.63) and dietary CP content (r.s.d = 0.028, r2= 0.59). For biological reasons we propose a non‐linear model that allows prediction of dry‐ and organic‐matter digestibility from faecal CP Content with reasonable Precision (r.s.d = 0.038, 0.036, r2= 0.65, 0.74, respectively). This will be adequate for many studies, especially for free‐living animals in rangelands.
Interactions between N supply and N uptake by perennial ryegrass, 15N recovery and soil pH for four acid Scottish soils
Authors: Logan  , Thomas
Published: March 2003

The effects of NH4+−N, NO3−‐N or urea‐N addition on N uptake by perennial ryegrass (Lolium perenne), 15N recovery and pH of four limed and unlimed soils were determined in a pot experiment over 10 weeks. The best form of N in terms of herbage N uptake and fertilizer recovery differed between the soils. Recovery of applied 15N in herbage was greatest for the soil with the lowest pH and highest organic matter content, and overall recovery in the soil–plant system was influenced more by soil type than by N form. There was always an apparent mineralization of soil N when perennial ryegrass was present. Soil pH changes ranged from +0·11 to −0·58 units for the unlimed soils and from +0·03 to −1·06 units for the limed soils. The use of NO3−‐N rather than NH4+‐N or urea‐N avoided further acidification. Lime increased herbage N only from the soils with the lowest pH values. Although the acidifying effect of NH4+‐fertilizer was alleviated, liming may increase nitrification and possibly N loss via denitrification and/or leaching in the field.

The major influence of soil type on herbage N uptake, pH response to the treatments and fertilizer recoveries implies that liming and fertilizer N management decisions should consider soil characteristics, such as organic matter, clay contents and pH.
The effect of mechanical treatment on the drying rates of Italian and perennial ryegrasses
Authors: Frost  , Binnie
Published: March 2003

On two occasions in 1995 the effects of severity of conditioning and pressing on the drying rate of Italian (Lolium multiflorum Lam.; IR) and perennial (Lolium perenne L.; PR) ryegrass were assessed. The cut herbage was either left unconditioned (0C) or conditioned by passing through a laboratory scale macerator three (3C) or six (6C) times after which the herbage was placed into wire mesh trays and either left unpressed (0P) or pressed (P). The twelve treatment combinations (two species × three conditioning levels × two pressings) were replicated three times on each of the two occasions. On each occasion the trays plus herbage were weighed at hourly intervals over an ≈6‐h period and dry matter (DM) of the herbage was estimated from the weight change. Pressing treatment gave, on average, a negative effect on the drying rate of the herbage. Conditioning significantly (P < 0·001) increased the drying rate of the herbage. Compared with 0C herbage, the greatest increase in drying rate was obtained with the 3C treatment; the additional conditioning imposed by the 6C treatment produced only a small further increase in drying rate. Drying constants calculated for each treatment combination showed that IR dried 1·45 times faster than PR and that, compared with 0C, herbage drying rate was 2·18 and 2·38 times greater as a consequence of the 3C and 6C treatments respectively. Pressed (P) herbage dried at a rate of 0·90 of that of the unpressed herbage (0P).
Enhancement of botanical diversity of permanent grassland and impact on hay production in Environmentally Sensitive Areas in the UK
Authors: Hopkins  , Pywell  , Peel  , Johnson  , Bowling
Published: March 2003

Five methods for increasing the botanical diversity of permanent grassland, either by sowing site‐specific species‐rich grass/forb seed mixtures (strip‐seeding; or over‐sowing after sward disturbance by light harrowing, partial rotary cultivation or turf removal), or by introducing transplanted plug plants, were compared with a control treatment in replicated field experiments on six farm sites in Environmentally Sensitive Areas (ESAs) in England and Wales. Effects on herbage production under hay cutting in July and on botanical composition were recorded in the two subsequent years. Turf removal before sowing was the only treatment that significantly reduced herbage production; this treatment also had the greatest effect on increasing botanical diversity (to a mean of twenty‐eight plant species per site compared with fifteen species for the control 2 years after sowing). The least successful establishment of sown species resulted from light harrowing before sowing; the rotary‐cultivated and strip‐seeded treatments increased species diversity, although by less than turf removal. Successful establishment of introduced species was greatest on sites having a low soil nutrient status. Species that established successfully from seed on most sites and treatments included the grasses Alopecurus pratensis, Cynosurus cristatus, Festuca rubra and Phleum pratense, and the forbs Achillea millefolium, Leucanthemum vulgare, Plantago lanceolata and Prunella vulgaris; in addition, Centaurea nigra, Hypochoeris radicata and Lotus corniculatus were also established by one or more methods on most sites. Lychnis flos‐cuculi established successfully on mesotrophic sites, and Medicago lupulina on calcareous sites. Several species failed to establish at all or most sites where they were sown, e.g. Helianthemum nummularium, Pimpinella saxifraga and Rhinanthus minor. Most transplanted plug‐plant species established successfully in the short term, but many failed to persist or their frequency in the sward remained low; exceptions included A. millefolium and P. lanceolata. The results are discussed in relation to the requirements for management to further the objectives of ESAs and agri‐environmental schemes.
The response of manured forage maize to starter phosphorus fertilizer on chalkland soils in southern England
Authors: Withers  , Peel  , Chalmers  , Lane  , Kane
Published: March 2003

The impact of various starter phosphorus (P) fertilizers on the growth, nutrient uptake and dry‐matter (DM) yield of forage maize (Zea mais) continuously cropped on the same area and receiving annual, pre‐sowing, broadcast dressings of liquid and semi‐solid dairy manures was investigated in two replicated plot experiments and in whole‐field comparisons in the UK. In Experiment 1 on a shallow calcareous soil (27 mg l−1 Olsen‐extractable P) in 1996, placement of starter P fertilizer (17 or 32 kg ha−1) did not benefit crop growth or significantly (P > 0·05) increase DM yield at harvest. However, in Experiment 2 on a deeper non‐calcareous soil (41 mg l−1 Olsen‐extractable P) in 1997, placement of starter P fertilizer (19 or 41 kg P ha−1), either applied alone or in combination with starter N fertilizer (10 or 25 kg N ha−1), significantly increased early crop growth (P < 0·01) and DM yield at harvest by 1·3 t ha−1 (P < 0·05) compared with a control without starter N or P fertilizer. Placement of starter N fertilizer alone did not benefit early crop growth, but gave similar yields as P, or N and P, fertilizer treatments at harvest. Large treatment differences in N and P uptake by mid‐August had disappeared by harvest. In field comparisons over the 4‐year period 1994–97, the addition of starter P fertilizer increased field cumulative surplus P by over 70%, but without significantly (P > 0·05) increasing DM yield, or nutrient (N and P) uptake, compared with fields that did not receive starter P fertilizer. The results emphasized the extremely low efficiency with which starter P fertilizers are utilized by forage maize and the need to budget manure and fertilizer P inputs more precisely in order to avoid excessive soil P accumulation and the consequent increased risk of P transfer to water causing eutrophication.
Effect of formic acid and a bacterial inoculant on the amino acid composition of grass silage and on animal performance
Authors: Winters A. L. , Fychan R. , Jones R.
Published: March 2003

An Italian ryegrass and hybrid ryegrass sward was harvested on 11 May 1994. The mean dry‐matter (DM) content of the herbage was 197 g kg–1fresh matter (FM), and mean nitrogen and water‐soluble carbohydrate contents were 20 and 272 g kg–1DM respectively. Approximately 72% of total nitrogen (TN) was in the form of protein‐nitrogen. The herbage was treated with either no additive, formic acid (3·3 l t–1) (Add‐F, BP) or inoculant (2·3 l t–1) (Live‐system, Genus) and ensiled in 100 t silos. Changes in effluent composition with time showed that silage fermentation and protein breakdown were delayed by treatment with formic acid. Formic acid and inoculant treatments also inhibited amino acid catabolism during ensilage. All silages were well fermented at opening with pH values < 4·0 and ammonia‐N concentrations of ≤ 50 g kg–1TN after 120 d ensilage. Treatment had an effect on protein breakdown as measured by free amino acid concentration, with values of 21·5, 18·2 and 13·2 mol kg–1N at opening (191 d) for untreated, formic acid‐treated and inoculated silages respectively. Amino acid catabolism occurred to the greatest extent in untreated silages with significant decreases in glutamic acid, lysine and arginine, and increases in gamma amino butyric acid and ornithine. The silages were offeredad libitumwithout concentrate supplementation to thirty‐six Charolais beef steers for a period of 69 d (mean live weight 401 kg). Silage dry‐matter intakes and liveweight gains were significantly (P < 0·05) higher on the treated silages. Silage dry‐matter intakes were 7·42, 8·41 and 8·23 kg d–1(s.e.d. 0·27) with liveweight gains of 0·66, 0·94 and 0·89 kg d–1(s.e.d. 0·058) for untreated, formic acid‐treated and inoculated silage‐fed cattle respectively. In conclusion, additives increased the intake of silage and liveweight gain by the beef steers, and it is suggested that this may be caused in part by the amino acid balance in these silages.
Soil N contributes to the oscillations of the white clover content in mixed swards of perennial ryegrass under conditions that simulate grazing over five years
Authors: Loiseau P. , Soussana J.‐F. , Louault F. , Delpy R.
Published: March 2003

The effect of the initial N‐supplying capacity of soils (SoilN, 90–230 kg N ha–1 year–1) was tested on the dry‐matter and N yields of pure or mixed white clover and perennial ryegrass swards, managed under simulated grazing over a 5‐year period. The cumulated N harvested in the mixed swards was similar, both for white clover and perennial ryegrass, but the proportion of white clover showed oscillations over a 2‐year period. In the first year, the SoilN effect was similar to that of fertilizer N. During the course of the experiment, the effect was always positive on the pure perennial ryegrass sward, alternately negative and nil for the white clover in the mixed sward and alternately positive and nil for the perennial ryegrass in the mixed sward; the period of these oscillations was 2 years. From the third regrowth period after sowing, the ratio between the actual N concentration and the concentration non‐limiting to growth for the perennial ryegrass in the mixed sward, increased above that of the pure perennial ryegrass sward. It was in turn greater in the soils that were initially poor and then greater in those that were initially rich in soil N. The periodic oscillation of the initial SoilN effects implies that the initial SoilN gradient was alternately compensated and restored. It was concluded that N fluxes are partly responsible for the temporal oscillations in the proportion of white clover in mixed swards.
Implications of grazing by sows for nitrate leaching from grassland and the succeeding cereal crop
Authors: Eriksen J.
Published: March 2003

Outdoor pig production may have benefits in terms of animal welfare but could be undesirable in terms of nutrient losses. In paddocks on sandy soil grazed by lactating sows, nitrate leaching was determined using the suction cup technique from the start of grazing in October to after the following barley/pea wholecrop with perennial ryegrass. The inorganic N concentration in soil was uneven after sow grazing, with the highest values found near the feeding area. In contrast to low nitrate leaching in the year of grazing (25–30 kg of N ha–1), losses were considerable in the following autumn and winter. Throughout the measuring period of 18 months, nitrate leaching inside paddocks was on average 320 kg of N ha–1 with the major part near the feeding area. Ten metres from the feeding area, leaching losses were 500 kg of N ha–1 and, at 16 m distance, losses were 330 kg of N ha–1. At 22 and 28 m distance from the feeding area, about 200 kg of N ha–1 was leached and outside paddocks about 100 kg of N ha–1. The combination of a sandy soil with high winter rainfall leads to a large proportion of the N surplus being lost by nitrate leaching near the feeding area. To reduce nitrate leaching, stocking density and the level of dietary nutrient input must be adjusted, and more uniform distribution might be achieved by manipulating the excretory behaviour of the sows.
No relationship between leaf size and yield in medium leaf size white clover varieties under rotational sheep grazing and cutting
Authors: Williams T. A , Abberton M. T. , Thornley W. , Rhodes I.
Published: March 2003

Nine medium leaf size varieties of white clover (Trifolium repens L.) were grown in field plots with perennial ryegrass (Lolium perenne L.) variety Fennema, and yield measurements were taken under both cutting and rotational sheep grazing. The sampling and management protocols in the cut plots mirrored those for the National List testing of white clover varieties in the UK. Dry‐matter yields of the white clover and perennial ryegrass components of the mixture were recorded for six cuts in each of three harvest years. White clover yields were highest under cutting, perennial ryegrass yields under grazing. Significant differences were seen between the yields of white clover varieties, and significant interactions between white clover yields and management type were also observed. This interaction effect was not seen with respect to perennial ryegrass yields. No correlation was observed between leaf size and white clover dry‐matter yield under either management type. The results suggest that leaf size, on the scale of variation represented within a leaf size category, is not a good predictor of yield under rotational sheep grazing or cutting. The significance of these results for varietal evaluation and for ascertaining the underlying bases for yield differences is discussed.
Net photosynthetic rate of cocksfoot leaves under continuous and fluctuating shade conditions in the field
Authors: Peri P. L. , McNeil D. L. , Moot D. J. , Varella A. C. , Lucas R. J.
Published: March 2003

Maximum light‐saturated photosynthetic rate (Pmax) and stomatal conductance (gs) of field‐grown cocksfoot (Dactylis glomerataL.) leaves in a silvopastoral system were measured at different times under moderate (850–950 µmol m−2s−1photosynthetic photon flux density, PPFD) and severe shade (85–95 µmol m−2s−1PPFD). Also Pmax and gs were measured after 30, 60 and 180 min of severe shade to determine the lag in the rise of photosynthesis rate from low to high irradiance levels (induction state). The highest Pmax and gs values obtained were 26·5 µmol CO2 m−2s−1and 0·41 mol H2O m−2s−1in non‐limiting conditions with full sunlight (1900 µmol m−2s−1PPFD). These values were defined as standardized dimensionless Pmaxs=1 and gss=1 for comparison of treatment effects. The Pmaxsunder severe shade decreased by 0·004 units per minute from 1 to 180 min and reached a steady‐state of 0·37 units after 140 min. Under moderate shade, Pmaxsdecreased by 0·002 units per minute from 1 to 120 min and reached a steady‐state of 0·76 units. The time required to reach full induction on return to full sun (Pmaxs=1) was 15 min after 30 min of severe shade and 37 min after 180 min of shade. Mathematical equations were derived to describe the changes in Pmaxsand gssunder severe and moderate shade and during induction. The rate of change of gsswas slower than for Pmaxson entering shade and also slower during the subsequent induction process. This indicated other factors in addition to gs were operating in the reduction and increment of Pmax and a two‐step model to explain this is proposed. The defined photosynthetic responses of cocksfoot leaves to fluctuating light regimes could be used to develop quantitative predictions of Pmax for inclusion in a canopy photosynthesis model of silvopastoral systems.
A new electrosurgical loop technique for laparoscopic supracervical hysterectomy
Authors: Dequesne Jacques , Schmidt Norman , Frydman René
Published: March 2003

Objective

To evaluate the reduction of operating time during supracervical laparoscopic hysterectomy using an electric loop.

Design

Prospective clinical study.

Setting

Lausanne Endoscopic Center, Switzerland.

Subjects

30 women who underwent supracervical laparoscopic hysterectomy.

Intervention

A new electric loop has been designed, to separate the uterus from the cervix more quickly, by faster cutting, during supracervical hysterectomy.

Main outcome measure

The time taken to separate the uterus from the cervix.

Results

The preliminary evaluation indicates a reduction of time of at least 80%. Another advantage is the clean cut, and no complications to adjacent organs have been observed.

Conclusion

The new loop allows an evident reduction of operating time during supracervical laparoscopic hysterectomy.
Should women with carcinoma of the uterine cervix be treated surgically?
Authors: Grigsby Perry W.
Published: March 2003

Objective

The purpose of this article is to objectively evaluate the merits of surgery and radiotherapy in the treatment of women with early stage carcinoma of the uterine cervix.

Design

Retrospective review of the literature.

Results

Surgery and radiotherapy are both utilized in the treatment of women with carcinoma of the uterine cervix. Either surgery or radiotherapy can be used in the treatment of patients with early stage disease (carcinoma in situ, stages Ia to IIa). However, moderate controversy surrounds the issue of standard therapy for women with stages Ib and IIa cervical cancer. There is no evidence that both treatments should be utilized together for that group. Quality of life and survival outcomes are excellent for women with early stage cervical cancer treated with radiotherapy. Women with stages Ib2 and IIa disease should receive primary radiotherapy rather than surgery in order to avoid the possibility of also requiring postoperative irradiation and its associated costs and complications. The standard treatment for women with advanced stages (IIb, III, and IVa) of carcinoma of the uterine cervix is radiotherapy; surgical therapy is not utilized for these women. Adjuvant chemotherapy has not demonstrated a survival advantage and remains experimental.

Conclusion

Surgery and radiotherapy are utilized in the treatment of patients with carcinoma of the cervix. Selection criteria should be developed to guide individualized patient treatment.
Laparoscopic removal of benign uterine and adnexal masses during pregnancy
Authors: Mattei Alberto , Giannone Ettore , Carlo Di Renzo Gian , Gerli Sandro
Published: March 2003

Objective

To report three cases of laparoscopic treatment of benign uterine and adnexal masses during pregnancy and to discuss the feasibility of such procedures.

Interventions

A pedunculated myoma, an ovarian teratoma and a luteal ovarian cyst were laparoscopically treated during pregnancy. The patients' pregnancies were at 8, 7 and 11 weeks of gestation, respectively. The procedure times were 72, 65 and 53 min, while the estimated blood losses were 60, 100 and 80 ml, respectively. No complications were observed and the pregnancies were completed with a vaginal delivery in the first two cases and with a Caesarean section in the third case.

Conclusions

Laparoscopic management of gynaecological masses during pregnancy is still controversial. This report confirms that laparoscopy might be considered to be a safe, reliable and advantageous technique for the management of selected gynaecological pathologies during pregnancy.
Diagnostic and therapeutic hysteroscopy for traumatic intrauterine adhesions after induced abortions: clinical analysis of 365 cases
Authors: Feng Zuanchong C. , Yang Bangyuan , Shao Jinyu , Liu Suping
Published: March 2003

Objective

To determine the value of hysteroscopy for the diagnosis and treatment of traumatic intrauterine adhesions after induced abortion.

Design

A retrospective study of 365 patients.

Setting

Shanghai Institute of Planned Parenthood Research, the International Peaceful Maternity and Children Health Hospital, and the Shanghai First Maternity and Infant Health Hospital.

Subjects

365 patients with traumatic intrauterine adhesions after induced abortions were included in the study, of whom 351 complained of amenorrhoea or hypomenorrhea before treatment, and 186 of whom wanted to have a child.

Interventions

In all the patients, the diagnoses and types of intrauterine adhesions were confirmed by hysteroscopy, and the adhesions were separated using micro scissors and biopsy forceps under hysteroscopic view. Most procedures were carried out with ultrasound monitoring.

Results

In 346 out of 365 patients (94.8%) intrauterine adhesions were released successfully after 1–4 episodes of surgery. Of the 351 patients with amenorrhoea or hypomenorrhea before treatment, 294 (83.76%) had normal or near‐normal regular menstruation after therapy. Of the 186 patients who wanted to have a child and were followed up for more than 12 months after the withdrawal of contraception, 156 (83.87%) had intrauterine pregnancies. Among these 156 patients, 145 had full‐term pregnancies, with three instances of retained placenta and one of placental implantation, and 11 had early spontaneous abortions.

Conclusion

Hysteroscopy is of great value in the diagnosis and treatment of intrauterine adhesions after induced abortions. Patients were managed with few complications after hysteroscopic lysis. Most patients regained their fertility and normal regular menstruation.
Hysteroscopic tubal cannulation: long‐term results
Authors: Maikis Roseann , Anderson Ted L. , Daniell James F.
Published: March 2003

Objective

To examine the success rate and long‐term results of hysteroscopic cannulation under laparoscopic control for proximal fallopian tube obstruction.

Design

Retrospective outcome analysis.

Setting

Referral endoscopic private practice for infertility.

Subjects

29 patients referred with proximal tubal cornual obstruction, confirmed by hysterosalpingography or laparoscopy, with other tubal factors confounding infertility. All patients underwent hysteroscopic proximal guide wire tubal cannulation under laparoscopic guidance.

Main outcome measures

Pregnancy outcomes from 2 to 5 years following the procedure.

Results

Of a total of 29 attempts at tubal cannulation, 16 were unsuccessful at the time of surgery (55%), while 13 patients had successful proximal tubal cannulation, and patency confirmed via intraoperative chromotubation. Of these 13, three were lost to long‐term follow up. Among the 10 remaining patients, there were three pregnancies: two term deliveries and one ectopic pregnancy. The remaining seven of the 10 patients with successful cannulations did not achieve pregnancy (70%) and elected for in vitro fertilization or adoption.

Conclusion

After over a decade of reports of hysteroscopic tubal cannulation, this procedure has been used as the first‐line, and often only, therapy for proximal tubal obstruction. The results of this series indicate that pregnancy rates are not as favourable as reported by others. These long‐term poor results should be considered when counselling patients with cornual occlusion about this surgery or other assisted reproductive options.
Is hysteroscopic appearance a safe means of differentiating malignant from benign endometrial polyps in postmenopausal women?
Authors: De Almeida Patrícia , Reis Silva , Nogueira Antonio A. , Reis Francisco J. C. dos , Campolungo Adriana , Carrara Hélio H. A. , De Andrade Jurandyr M.
Published: March 2003

Objective

To determine whether the hysteroscopic appearance of endometrial polyps in postmenopausal women offers a safe method of differentiating premalignant and malignant polyps from those that are benign.

Design

We performed a retrospective analysis of 60 postmenopausal patients with endometrial polyps evaluated by diagnostic hysteroscopy. These polyps were histologically examined after removal in all patients.

Results

All polyps had a benign hysteroscopic appearance. Histological findings were: endometrial polyp without atypia in 57 patients (95%), endometrial polyp with mild atypia in one patient (1.7%), and clear‐cell adenocarcinoma in two patients (3.3%).

Conclusion

Hysteroscopic appearance did not provide a safe method of differentiating malignant and atypical from benign endometrial polyps. The presence of endometrial neoplasia in our series argues for the histological diagnosis of endometrial polyps occurring after the menopause.
In vitro comparison of two methods of anchoring the vagina during the Burch procedure
Authors: Simon Philippe , Salvia Patrick , Fellemans Caroline , Buxant Frédéric , Anaf Vincent
Published: March 2003

To compare the quality of the vaginal attachment of classical Burch anterior colposuspension with laparoscopic colposuspension with polyester mesh fixed with tackers.

The study was performed on three fresh cadavers. The extension and the strength of polyester braided fibre (Ticron) sutures on one side were compared with those of polyester mesh (Mersilene) tacked into the Burch site on the other side, by means of progressive traction measured by a linear transducer.

When progressive traction was applied in the two systems studied, both displayed moderate elongation. The Mersilene mesh appeared to be significantly more elongated than Ticron suture, with a partial return to the original length. In no case (Ticron suture or tacked Mersilene mesh) was a rupture of the vaginal fixation seen, when traction of up to 2 kg was applied.

Mersilene mesh appears to elongate more than the classical suture when placed under traction. This casts doubt on the quality of the suspension obtained, even though no rupture was observed.
Hysteroscopic findings in postmenopausal patients using tibolone
Authors: Maia Hugo , Machado Simone , Borges Silvana , Chagas Ariane , Maltez Amélia , Coutinho Elsimar M.
Published: March 2003

Objective To investigate the cause of uterine bleeding in tibolone users who were referred to an endoscopy unit.

Design Hysteroscopy followed by endometrial biopsy was carried out in all patients. The endometrial echo was measured by transvaginal sonography prior to hysteroscopy and compared with hysteroscopic findings.

Results Endometrial polyps were the pathological lesions most frequently diagnosed by hysteroscopy in tibolone users. However, their diagnosis was missed by blind endometrial biopsy in all cases. The surrounding endometrium was always atrophic even when a polyp was present in the uterine cavity. There was one case of endometrial carcinoma which occurred in association with a polyp.

Conclusion Tibolone does not exert any stimulatory effect on the normal endometrium. However, intrauterine lesions such as polyps can grow in response to this treatment. The presence of polyps is associated with abnormal uterine bleeding in these patients.
A prospective multicentre study of laparoscopic complications related to the direct‐entry technique
Authors: Kaloo Philip , Cooper Michael , Reid Geoffrey
Published: March 2003

Objective ‘Direct entry’ is a laparoscopic entry technique which involves the insertion of a trocar directly into the abdominal cavity without a prior pneumoperitoneum. The objective of this study was to evaluate the major complication profile of this relatively uncommon entry technique in consecutive patients undergoing diagnostic or operative laparoscopy.

Design Over a period of 3 years, 1838 consecutive patients were recruited from the practice of two experienced gynaecological endoscopists. Complications directly related to the entry technique which occurred intraoperatively, either immediately or up to 2 weeks postoperatively, were recorded prospectively. Complications were considered to be events which significantly prolonged or altered the planned procedure, delayed discharge or led to a prolongation of convalescence.

Results Only one major injury occurred, a perforation of the large bowel, which was diagnosed immediately and managed laparoscopically with no long‐term sequelae.

Conclusion When compared with other laparoscopic entry techniques, direct entry is a safe, cheap, effective and underutilized modality for entering the peritoneal cavity in ‘low‐risk’ patients.
The route for hysterectomy: is it time to change?
Authors: Najia Salim K. , Bhatia Kalsang , Hall Vince
Published: March 2003

Objective To determine the proportion of hysterectomies done by the vaginal route for all benign gynaecological indications, at our centre, and to assess our performance with respect to the feasibility of bilateral salpingo‐oöphorectomy, and also to identify any major complications.

Design A retrospective analysis of case notes on 99 consecutive hysterectomies done for benign gynaecological indications.

Setting A district general hospital.

Results Out of 99 hysterectomies, 92 were done by the vaginal route, (excluding four laparoscopy‐assisted vaginal hysterectomies), with no significant major complications except for one conversion to laparotomy. Bilateral salpingo‐oöphorectomy was successfully performed in 98.3% of patients in whom it was planned. There was no significant uterine prolapse in 78% of patients undergoing vaginal hysterectomy, and the largest uterus removed vaginally weighed 1146 g.

Conclusions Vaginal hysterectomy is feasible in most patients with benign gynaecological indications. Where possible contraindications exist, the use of preliminary laparoscopy should be encouraged, to help in the proper selection of patients and perhaps to remedy any relative contraindications. Gynaecologists need to appraise the vaginal route, and there is a strong need to address training issues as far as vaginal surgery is concerned.
Prednisone and low‐dose activated prothrombin complex concentrates for FVIII inhibitor in nonhaemophilic patients
Authors: JI Linxiang , Yang Renchi , Yang Deguang , Chen Zhongkai , Xing Shuhua , Tian Mengsu , Sun Yin
Published: March 2003

Eight nonhaemophilic patients with factor VIII (FVIII) inhibitors were reported. There was no difference in sex distribution. Median age at diagnosis was 62 years (ranging from 14 to 73 years). No associated disorders were revealed and all the patients were presented with severe muscular or arthral bleeding. Inhibitor titre was measured by the Bethesda method, which were 6.4, 126.0, 155.0, 4.8, 56.0, 13.5, 35.0 and 150.0 BU mL−1, respectively, at diagnosis. FVIII:C levels were less than 1 U dL−1 in seven patients and less than 2 U dL−1 in one patient. The median vWF:Ag level was 210% (ranging from 80% to 340%). All the patients had good response to activated prothrombin complex concentrates for acute bleeding episodes and prednisone for inhibitor elimination. Inhibitors completely eliminated in seven patients within a follow‐up duration over 1 year, and one patient died of intracranial haemorrhage when her inhibitor titre decreased to 4.5 BU mL−1 and FVIII:C increased to 21 U dL−1.
Recombinant factor VIIa in continuous infusion during central line insertion in a child with factor VIII high‐titre inhibitor
Authors: Montoro J. B. , Altisent C. , Pico M. , CabaÑas M. J. , Vila M. , Puig L. L.
Published: March 2003

Recombinant factor VIIa (rFVIIa) is a recently added new tool for the treatment of haemophilia patients with inhibitors. A major drawback in the use of rFVIIa is its short half‐life, which necessitates frequent bolus injections. Thus the use of rFVIIa in continuous infusion appears to be a good alternative. We describe the use of rFVIIa, administered by continuous infusion with a minipump during the insertion of a central venous catheter in a child with a high‐titre factor VIII inhibitor. rFVIIa was administered as an intravenous bolus (90 μg kg−1 [4.5 kIU kg−1]), 1 h prior to central line insertion, after which the continuous infusion was immediately started for 5 days. The infusion rate was based on the clearance obtained from a previous pharmacokinetic study. Effective haemostasis and normal healing of surgical incisions were achieved after central line insertion. No local thrombophlebitis nor evidence of generalized activation of the coagulation cascade was observed. Single‐dose pharmacokinetic parameter values were clearance (Cl) 34.6 mL h−1 kg−1, volume of distribution (Vd) 40.6 mL kg−1 and mean residence time (MRT) 1.17 h. The recovery was 2.27% U−1 kg−1. rFVIIa showed a monophasic decay. Cl during continuous infusion was 23.4 ± 6.9 mL h−1 kg−1. The administration of rFVIIa by continuous infusion is effective, safe and more convenient when compared to other clotting factors. Moreover, continuous infusion provides significant economic savings (77% decrease in rFVIIa requirements).
Characterization of factor VIII/von Willebrand factor concentrates using a modified method of von Willebrand factor multimer analysis
Authors: Metzner  , Hermentin  , Cuesta‐Linker  , Langner  , MÜller  , Friedebold
Published: March 2003

In order to provide patients with von Willebrand disease a factor VIII (FVIII)/von Willebrand factor (vWF) concentrate of reproducible quality, an SDS‐agarose gel electrophoresis method has been established to determine the content of the high molecular weight multimers (band 11 and higher) of vWF. This method has been used to characterize the content of high molecular weight vWF multimers in Humate® P/Haemate® P, a commercial FVIII/vWF concentrate. The average content of high molecular weight vWF multimers of 47 batches of Humate® P/Haemate® P has been determined to be 84.1% of the corresponding bands in normal human plasma. Use of this multimer analysis method for the characterization of five further commercial products revealed clear differences with respect to the high molecular weight vWF multimer content. Furthermore, there is a linear correlation (r2 = 0.73) between the content of high molecular weight vWF multimers and the specific activity of vWF (determined as vWF:RCoF/vWF:Ag). The method described here for analysis of the content of high molecular weight vWF multimers is a reliable and reproducible method to characterize this class of factor concentrates with respect to vWF multimer composition.