bluuebunny/crossref_metadata_2025 huggingface dataset:
Moveout analysis for tranversely isotropic media with a tilted symmetry axis
Authors: Tsvankin Ilya
Published: November 2003

The transversely isotropic (TI) model with a tilted axis of symmetry may be typical, for instance, for sediments near the flanks of salt domes. This work is devoted to an analysis of reflection moveout from horizontal and dipping reflectors in the symmetry plane of TI media that contains the symmetry axis. While for vertical and horizontal transverse isotropy zero‐offset reflections exist for the full range of dips up to 90°, this is no longer the case for intermediate axis orientations. For typical homogeneous models with a symmetry axis tilted towards the reflector, wavefront distortions make it impossible to generate specular zero‐offset reflected rays from steep interfaces. The ‘missing’ dipping planes can be imaged only in vertically inhomogeneous media by using turning waves. These unusual phenomena may have serious implications in salt imaging.  In non‐elliptical TI media, the tilt of the symmetry axis may have a drastic influence on normal‐moveout (NMO) velocity from horizontal reflectors, as well as on the dependence of NMO velocity on the ray parameter p (the ‘dip‐moveout (DMO) signature’). The DMO signature retains the same character as for vertical transverse isotropy only for near‐vertical and near‐horizontal orientation of the symmetry axis. The behaviour of NMO velocity rapidly changes if the symmetry axis is tilted away from the vertical, with a tilt of ±20° being almost sufficient to eliminate the influence of the anisotropy on the DMO signature. For larger tilt angles and typical positive values of the difference between the anisotropic parameters ε and δ, the NMO velocity increases with p more slowly than in homogeneous isotropic media; a dependence usually caused by a vertical velocity gradient. Dip‐moveout processing for a wide range of tilt angles requires application of anisotropic DMO algorithms.  The strong influence of the tilt angle on P‐wave moveout can be used to constrain the tilt using P‐wave NMO velocity in the plane that includes the symmetry axis. However, if the azimuth of the axis is unknown, the inversion for the axis orientation cannot be performed without a 3D analysis of reflection traveltimes on lines with different azimuthal directions.
Algorithms for staggered‐grid computations for poroelastic, elastic, acoustic, and scalar wave equations
Authors: Özdenvar Turgut , McMechan George A.
Published: November 2003

Heterogeneous wave equations are more complicated numerically than homogeneous wave equations, but are necessary for physical validity. A wide variety of numerical solutions of seismic wave equations is available, but most produce strong numerical artefacts and local instabilities where model parameters change rapidly. Accuracy and stability of heterogeneous equations is achieved through staggered‐grid formulations. A new pseudospectral staggered‐grid algorithm is developed for the poroelastic (Biot) equations. The algorithm may be reduced to handle the elastic and acoustic limits of the Biot equations. Comparisons of results from poroelastic, elastic, acoustic and scalar computations for a 2D model show that porous medium parameters may affect amplitudes significantly. The use of homogeneous wave equations for modelling of a heterogeneous medium, or of a centred rather than a staggered grid, or of simplified (e.g. acoustic) wave equations when elastic or poroelastic media are synthesized, may produce erroneous or ambiguous interpretations.
Predicting horizontal velocities from well data
Authors: Andrea M. , Sams M.S. , Worthington M.H. , King M.S.
Published: November 2003

The Imperial College borehole test site consists of four boreholes with depths lying between 260 and 280 m. The boreholes intersect several cyclical sequences of sandstones, mudstones and limestones. The formations are highly laminated and ultrasonic measurements on preserved core have shown that the mudstones are intrinsically anisotropic. Little or no anisotropy is associated with the sandstones and limestones. A scheme is proposed to predict synthetic vertical and horizontal P‐ and S‐wave logs. Combining (an)isotropic effective medium theories, the Gassmann equation and Backus averaging, the scheme extends previous sand‐shale models to transversely isotropic rock formations. The model assumes that the anisotropy is due to layering and due to the preferred horizontal orientation of the clay minerals, pores and cracks within the mudstones. The pores and cracks within the sandstones and limestones are randomly orientated. After fitting the model to the ultrasonic data to obtain the unknown parameters, the model successfully predicts the sonic log and the direct arrival times from a cross‐hole survey.
Marine seismic sources: QC of wavefield computation from near‐field pressure measurements
Authors: Ziolkowski A.M. , Johnston R.G.K.
Published: November 2003

A commercial marine seismic survey has been completed with the wavefield from the n‐element (single guns and clusters) airgun array measured for every shot using an array of n + 2 near‐field hydrophones, n of which were required to determine the source wavefield, the remaining two providing a check on the computation. The source wavefield is critical to the determination of the seismic wavelet for the extraction of reflection coefficients from seismic reflection data and for tying the data to wells.  The wavefield generated by the full array of interacting airguns can be considered to be the superposition of n spherical pressure waves, or notional source signatures, the n hydrophone measurements providing a set of n simultaneous equations for each shot. The solution of the equations for the notional source signatures requires three ingredients: the geometry of the gun ports and near‐field hydrophones; the sensitivity of each hydrophone recording channel; and the relative motion between the near‐field hydrophones and the bubbles emitted by the guns. The geometry was measured on the back deck using a tape measure. A calibration data set was obtained at the approach to each line, in which each gun was fired on its own and the resulting wavefield was measured with the near‐field hydrophones and recorded. The channel sensitivities, or conversion from pressure at the hydrophones to numbers on the tape, were found for each near‐field hydrophone channel using the single gun calibration data, the measured geometry, and the peak pressure from each gun, known from the manufacturer’s calibration. The relative motion between the guns and hydrophones was obtained from the same calibration data set by minimizing the energy in the computed notional source signatures at the guns which did not fire. The full array data were then solved for the notional source signatures, and the pressure was computed at the two spare hydrophones and compared with the actual recordings. The rms errors were 5.3% and 2.8% and would have been smaller if the hydrophone channel sensitivities had been properly calibrated beforehand and if the movement of the guns with respect to the hydrophones had been more restricted.  This comparison of the predicted and measured signatures at spare hydrophones can, in principle, be done on every shot and we recommend that this be implemented as a standard quality control procedure whenever it is desired to measure the wavefield of a marine seismic source.
A novel mobile multipole system (MUCEP) for shallow (0–3 m) geoelectrical investigation: the ‘Vol‐de‐canards’ array
Authors: Panissod C. , Dabas M. , Jolivet A. , Tabbagh A.
Published: November 2003

The aim of this paper is to point out the advantages of multipoles for the exploration of the very near subsurface (0–3 m) by continuous profiling. We propose a new geometry with eight poles for a MUltipole Continuous Electrical Profiling (MUCEP) measuring system, where the array has a V‐shape and is thus called ‘Vol‐de‐canards’. A series of criteria including 3D numerical simulations are performed (direct and inverse modelling) to determine the optimal geometry and to compare its performance (in terms of depth of investigation and resolution of the geometry of the targets) with the other arrays (quadrupoles or rectangular‐type multipoles). This multipole was built together with a real‐time acquisition system. The multidepth maps obtained confirm the characteristics predicted by numerical simulations.
Topographic accessibility and the tectonic interpretation of gravity data
Authors: Daniel A. J. , Styles P.
Published: November 2003

During recent gravity surveys in Patagonia, we were unable to acquire data on the North Patagonian Icecap, which is completely inaccessible for land surveying. The Icecap is clearly of tectonic significance, but, because of its tectonic history, it is uplifted and rugged, and consequently inaccessible. Therefore the distribution of geophysical observations which can be acquired in a rugged field area is dependent on the tectonic history. This suggests that a tectonic history which is reconstructed from geophysical data may be systematically biased.

We use models of local and flexural isostasy to estimate the gravity errors associated with interpolation across inaccessible topography. The gravity error is largest for Pratt isostasy, where the mass deficit which supports the topography is at relatively shallow depths. The gravity error is least for flexural isostasy, because in this case the inaccessible topography is supported regionally by a mass deficit which extends beyond the inaccessible region.

An analytical flexural interpolation scheme is proposed for interpolation across data gaps associated with inaccessible topography. Flexural theory and Gauss’s theorem are used to predict the gravity anomaly due to the mass excess of the inaccessible topography. We apply this scheme to the North Patagonian Icecap, to demonstrate that flexural interpolation predicts a relative gravity low at the site of the Icecap, which would not be predicted by purely geometrical interpolation schemes.
Rice responses to drought under carbon dioxide enrichment. 1. Growth and yield
Authors: BAKER JEFFREY , HARTWELL ALLEN L. , BOOTE KENNETH , PICKERING NIGEL
Published: November 2003

Projections of future climate change include a strong likelihood of a doubling of current atmospheric carbon dioxide concentration ([CO2]) and possible shifts in precipitation patterns. Drought stress is a major environmental limitation for crop growth and yield and is common in rainfed rice production systems. This study was conducted to determine the growth and grain yield responses of rice to drought stress under [CO2] enrichment. Rice (cv. IR‐72) was grown to maturity in eight naturally sunlit, plant growth chambers in atmospheric carbon dioxide concentrations [CO2] of 350 and 700 μmol CO2 mol–1 air. In both [CO2], water management treatments included continuously flooded (CF) controls, flood water removed and drought stress imposed at panicle initiation (PI), anthesis (ANT), and both panicle initiation and anthesis (PI & ANT). The [CO2] enrichment increased growth, panicles plant–1 and grain yield. Drought accelerated leaf senescence, reduced leaf area and above‐ground biomass and delayed crop ontogeny. The [CO2] enrichment allowed 1–2 days more growth during drought stress cycles. Grain yields of the PI and PI & ANT droughts were similar to the CF control treatments while the ANT drought treatment sharply reduced growth, grain yield and individual grain mass. We conclude that in the absence of air temperature increases, future global increases in [CO2] should promote rice growth and yield while providing a modest reduction of near 10% in water use and so increase drought avoidance.
Biomass of primary and secondary vegetation in Rondônia, Western Brazilian Amazon
Authors: ALVES DIÓGENES , SOARES JOÃO VIANEI , AMARAL SILVANA , MELLO ELIANA , ALMEIDA SÉRGIO , DA SILVA OSMAN FERNANDES , SILVEIRA ANDREA
Published: November 2003

Biomass estimates of primary and different ages of secondary vegetation are reported for a tropical forest region in Rondônia, Western Brazilian Amazon. The estimates are based on published allometric equations, and on vegetation composition and allometric data collected in areas of primary forest and secondary vegetation of ages 2, 3, 5, 9, 11, 16 and 18 years. Primary forest biomass estimates varied from 290 to 495 t ha–1. Secondary vegetation biomass estimates accounted for 40–60% of the primary forest biomass after 18 years of abandonment. Secondary growth rates in lightly used areas are estimated to have varied from 6.6 to 8.7 t ha–1 y–1 between the third and the eighteenth years after abandonment. CO2 sequestration by regrowing vegetation is discussed for two scenarios of land abandonment.
The effect of climate change on an aphid–coccinellid interaction
Authors: SKIRVIN D.J. , PERRY J.N. , HARRINGTON R.
Published: November 2003

A model (Carter et al. 1982) that described the population dynamics of Sitobion avenae was modified and extended to include the population dynamics of the aphidophagous coccinellid, Coccinella septempunctata. The model was run under three different temperature regimes, corresponding to different degrees of warmth in typical English summers, and, in addition, within‐regime temperature was altered, to predict the likely effects of climatic change on the interaction between the aphid and coccinellid. The model predicts that the presence of coccinellids causes a reduction in the number of aphids of between 40 and 60 percent, and advances the Julian date of their maximum numbers. The model also predicts that an increase in temperature within a regime results in smaller maximum and total numbers of aphids. In the presence of coccinellids, aphids were predicted to be most successful in moderately warm summers. The predicted maximum number of coccinellids was not greatly affected by temperature, but their total number was, in a complex way. The greatest effect of coccinellids to reduce both maximum and total aphid numbers was predicted to occur for relatively hot summers. A sensitivity analysis was used to identify those aspects of the coccinellid submodel that require possible refinement.
Elevated CO2 and moisture effects on soil carbon storage and cycling in temperate grasslands
Authors: TATE K.R. , ROSS D.J.
Published: November 2003

In grassland ecosystems, most of the carbon (C) occurs below‐ground. Understanding changes in soil fluxes induced by elevated atmospheric CO2 is critical for balancing the global C budget and for managing grassland ecosystems sustainably. In this review, we use the results of short‐term (1–2 years) studies of below‐ground processes in grassland communities under elevated CO2 to assess future prospects for longer‐term increases in soil C storage.

Results are broadly consistent with those from other plant communities and include: increases in below‐ground net primary productivity and an increase in soil C cycling rate, changes in soil faunal community, and generally no increase in soil C storage. Based on other experimental data, future C storage could be favoured in soils of moderate nutrient status, moderate‐to‐high clay content, and low (or moderateIy high) soil moisture status. Some support for these suggestions is provided by preliminary results from direct measurements of soil C concentrations near a New Zealand natural CO2‐venting spring, and by simulations of future changes in grassland soils under the combined effects of CO2 fertilization and regional climate change.

Early detection of any increase in soil C storage appears unlikely in complex grassland communities because of (a) the difficulty of separating an elevated CO2 effect from the effects of soil factors including moisture status, (b) the high spatial variability of soil C and (c) the effects of global warming. Several research imperatives are identified for reducing the uncertainties in the effects of elevated atmospheric CO2 on soil C.
Responses of tree sap‐feeding herbivores to elevated CO2
Authors: DOCHERTY MAUREEN , WADE FRANCES , HURST DEBRA , WHITTAKER JOHN , LEA PETER
Published: November 2003

Five species of sap‐feeding homoptera were studied on Fagus sylvatica and Acer pseudoplatanus and exposed to elevated concentrations of carbon dioxide (600 μL L–1). The concentration of total soluble amino acids in foliage of F. sylvatica was unaffected by growing saplings in elevated atmospheric CO2 concentrations. Although experiments on individual aphids indicated poorer performance of Phyllaphis fagi (fewer, smaller nymphs produced), resultant populations did not differ from those in ambient (350 μL L–1) conditions. The area of beech foliage stippled by the leafhopper Fagocyba cruenta was similar at ambient and elevated CO2 concentrations. The concentration of total amino acids and that of serine of A. pseudoplatanus foliage were significantly lower at elevated CO2 concentrations. However, the relative growth rates of two aphid species Drepanosiphum platanoidis and Periphyllus testudinaceus and one leafhopper Ossiannilssonola callosa were not significantly different in elevated CO2. No evidence was found that, under the conditions of these experiments, populations of aphids and leafhoppers will change as concentrations of CO2 increase.
Using stable isotopes to determine soil carbon input differences under ambient and elevated atmospheric CO2 conditions
Authors: NITSCHELM JENNIFER , LÜSCHER ANDREAS , HARTWIG UELI , VAN KESSEL CHRIS
Published: November 2003

Quantitative estimates of soil C input under ambient (35 Pa) and elevated (60 Pa) CO2‐partial pressure (pCO2) were determined in a Free‐Air Carbon dioxide Enrichment (FACE) experiment. To facilitate 13C‐tracing, Trifolium repens L. was grown in a soil with an initial δ13C distinct by at least 5‰ from the δ13C of T. repens grown under ambient or elevated pCO2. A shift in δ13C of the soil organic C was detected after one growing season. Calculated new soil C inputs in soil under ambient and elevated pCO2 were 2 and 3 t ha–1, respectively. Our findings suggest that under elevated CO2 conditions, soil C sequestration may be altered by changes in plant biomass production and quality.
Brown Tide blooms in Long Island’s coastal waters linked to interannual variability in groundwater flow
Authors: LAROCHE JULIE , NUZZI ROBERT , WATERS ROBERT , WYMAN KEVIN , FALKOWSKI PAUL , WALLACE DOUGLAS
Published: November 2003

There has been a widespread increase in the reporting of harmful and ‘nuisance’ algal blooms in the coastal ocean over the past few decades. On the global scale this is suspected to be a consequence of coastal eutrophication, however, on a case‐by‐case basis there is usually insufficient evidence to discriminate between the effects of human and natural causal factors. Intense blooms of the ‘Brown Tide’ unicellular algae (Aureococcus anophagefferens) have occurred sporadically since 1985 in coastal waters of Eastern Long Island and have devastated the local commercial scallop fishery. Analysis of an 11‐year time‐series dataset from this region indicates that bloom intensity is correlated with higher salinities and inversely correlated with the discharge of groundwater. Laboratory and field studies suggest that whereas salinity is unlikely to represent a direct physiological control on Brown Tide blooms, the addition of inorganic nitrogen tends to inhibit Brown Tide blooms. Budget calculations indicate that the inorganic nitrogen supply from groundwater is 1–2 orders of magnitude higher than any other external source of nitrogen for this ecosystem. Biweekly time series data collected in 1995 demonstrate that Brown Tide blooms utilize dissolved organic nitrogen (DON) for growth, as evidenced by a large decrease in DON parallel with an increase in cell abundance. On an interannual basis, bloom intensity was also positively correlated with mean DON concentrations. We hypothesize that bloom initiation is regulated by the relative supply of inorganic and organic nitrogen, determined to a large extent by temporal variability in groundwater flow. The 1980s and 1990s were characterized by exceptionally high and interannually variable groundwater discharge, associated with a large‐scale climate shift over the North Atlantic. This, coupled with the time‐lagged discharge of groundwater with high nitrate concentrations resulting from increased fertilizer use and population increase during the 1960s and 1970s, may have been a key factor in the initiation of Brown Tide blooms in 1985.
Host plant effects on the performance of the aphid Aulacorthum solani (Kalt.) (Homoptera: Aphididae) at ambient and elevated CO2
Authors: AWMACK CAROLINE , HARRINGTON RICHARD , LEATHER SIMON
Published: November 2003

In future elevated CO2 environments, chewing insects are likely to perform less well than at present because of the effects of increased carbon fixation on their host plants. When the aphid, Aulacorthum solani was reared on bean (Vicia faba) and tansy (Tanacetum vulgare) plants under ambient and elevated CO2, performance was enhanced on both hosts at elevated CO2. The nature of the response was different on each plant species suggesting that feeding strategy may influence an insect’s response to elevated CO2. On bean, the daily rate of production of nymphs was increased by 16% but there was no difference in development time, whereas on tansy, development time was 10% shorter at elevated CO2 but the rate of production of nymphs was not affected. The same aphid clone therefore responded differently to elevated CO2 on different host plants. This increase in aphid performance could lead to larger populations of aphids in a future elevated CO2 environment.
CO2 effects on the water budget of grassland microcosm communities
Authors: FIELD CHRISTOPHER , LUND CHRISTOPHER , CHIARIELLO NONA , MORTIMER BARBARA
Published: November 2003

Experimental grassland ecosystems, in microcosms 0.2 m in diameter and with a 0.95 m soil column, varied in their responses to elevated partial pressure of CO2 (pCO2) and altered moisture inputs. Ecosystems on moderately fertile sandstone soil and with a typical mix of moderately fast‐growing sandstone species, responded to elevated pCO2 with decreases in mid‐season evapotranspiration of nearly 50%. This pattern reversed at the end of the growing season, and sandstone ecosystems under elevated pCO2 continued active transpiration farther into the summer drought. The sandstone ecosystems appeared to convert mid‐season water conservation into increased late‐season growth. Effects of increased pCO2 on ecosystem evapotranspiration were much smaller in ecosystems with very infertile serpentine soil and a diverse mixture of slow‐growing serpentine species.
Preservation of protein in wilted lucerne using formic, sulphuric or trichloroacetic acid
Authors: Vagnoni D. B. , Broderick G. A. , Muck R. E.
Published: November 2003

A laboratory‐scale experiment was conducted with lucerne (Medicago sativa) to determine the effects of acid treatment on proteolysis during ensiling and during subsequent in vitro ruminal protein incubations. Lucerne [300 g dry matter (DM) kg−1 forage] was either untreated (control) or treated with sulphuric, formic or trichloroacetic acid (a protein precipitant that stops enzyme activity) at levels sufficient to adjust immediately forage pH to 4·0, then conserved as either silage or hay. Time‐course data indicated that non‐protein nitrogen (N) formation was 70–90% complete after 1 d of fermentation in the silo. Non‐protein N concentrations (g kg−1 total N) were 177 at ensiling and increased to 567 (control), 426 (sulphuric), 398 (formic) and 263 (trichloroacetic) after 60 d of ensiling. Because non‐protein N in silage treated with formic and sulphuric acids was nearly three times greater than that in silage treated with trichloroacetic acid, it is clear that the typical acid treatments only slow proteolysis and do not destroy protease activity during ensiling. The ruminal protein degradation rate of conserved forages was slower than that of fresh‐cut forage that was preserved with dry ice immediately after cutting. The degradation rate of all acid‐treated forages was similar, indicating a consistent effect on ruminal degradation regardless of method of preservation. There was a clear effect of acid treatment on reducing the rate and extent of ruminal degradation of protein in lucerne hay.
Prediction of the chemical composition of white clover by near‐infrared reflectance spectroscopy
Authors: Berardo N.
Published: November 2003

The aim of this study was to assess near‐infrared reflectance spectroscopy (NIRS) as a rapid and reliable method for estimating quality parameters in white clover (Trifolium repens). NIRS calibrations were derived for ash, crude protein (CP), crude fibre (CF), neutral detergent fibre (NDF), acid detergent fibre (ADF) acid detergent lignin (ADL). To maximize variability, the set of samples for analysis was selected from field plots, harvested in two contrasting environmental locations over a period of 5 years. The samples were scanned using a NIR‐Systems model 5000 monochromator. A total of 145 samples was used to calibrate and cross‐validate the equations derived. A separate independent set (sixty‐five samples) was used for testing the predictions. Standard errors of calibration and cross‐validation, expressed as percentages of the mean, were 3·5 and 5·5 for ash, 3·0 and 4·2 for CP, 4·4 and 5·0 for CF, 3·7 and 4·7 for NDF, 3·3 and 4·2 for ADF and 14 and 16 for ADL respectively. The NIRS calibrations obtained from this study have the potential to be used in breeding programmes to assess the quality of white clover and for agronomic evaluations.
The effect of sward height on responses of mini‐swards of perennial ryegrass/white clover to slurry application
Authors: Wightman P. S. , Franklin M. F. , Younie D.
Published: November 2003

The influence of sward height at the time of slurry application on sward responses to slurry was investigated using perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) mini‐swards under greenhouse conditions. Pig slurry, cattle slurry and a fertilizer control were applied either to: swards cut 1 d before slurry application to heights of 2, 4 or 8 cm (CH2, CH4 or CH8); or to swards cut to 4 cm with regrowth intervals of 1, 4 or 8 d before slurry application (RI1, RI4 and RI8). Scorch, smother and growth of marked clover stolons and grass tillers were monitored after slurry application. Dry‐matter yields of both species were recorded over two harvests. Electrolyte leakage from leaves was used to assess leaf damage. Both slurries increased leakage, which was greatest from clover leaves, with biggest increases caused by pig slurry. Yield responses to slurry application varied with plant species and sward height. Reduced grass growth after slurry application to long swards (CH8, RI4, RI8) was probably caused by greater smother. In short swards (CH2), grass leaf growth was not depressed following slurry application but grass yields were reduced. Ammonia volatilization losses may have been greater in both long and short swards, contributing to yield reductions. Yield responses to slurry were greatest in swards cut to 4 cm, 1 d before application.
Short‐term leaf surface adhesion of heavy metals following application of sewage sludge to grassland
Authors: Aitken M. N.
Published: November 2003

In the short term, surface‐applied, digested, liquid sewage sludge may remain on grass leaf surfaces, leading to enhanced direct intake of potentially toxic elements by stock. The purpose of this field experiment was to investigate metal adhesion to herbage from liquid sewage sludge applications. Liquid digested sludge was applied at 0, 55 or 110 m3 ha−1 to an Agrostis capillaris and Holcus lanatus sward that had been cut to either 4 cm (short) or 13 cm (long). The application rate of metals was relatively low. One day after application (day 1), 8–13% of the sludge solids applied had adhered to the short grass treatment, accounting for 35–62% of the dry‐matter (DM) yield. On the long grass, 20–42% of the sludge dry solids adhered, accounting for 46–47% of the herbage DM yield. The content of all heavy metals in and on the grass herbage (Cu, Fe, Ni, Pb, Zn, Cr, Cd) was significantly increased (P < 0·05) at day 1. Cu concentrations in and on the grass decreased to 25 mg kg−1 after 16–29 d, Fe took 33–45 d to decline to 1000 mg kg−1 whereas Pb took 12–18 d to decline to 30 mg kg−1. It took 36 d for Cd, 43 d for Fe, Cu and Ni, and 57 d for Zn and Pb to be not significantly (P < 0·05) different from the control. Grass growth was the most significant factor(P < 0·05 for all treatments and metals) influencing the decline in grass metal concentration, explaining 65–96% of the variation. The cutting treatment, sludge application rate and metal species also significantly affected the extent and rate of reduction in metal contamination over time.
The accuracy of using the ratio of nitrogen to acid detergent fibre in faeces to partition nitrogen between faeces and urine in total excreta collections from ewes
Authors: White P. F. , Treacher T. T. , Termanini A. , Rihawi S.
Published: November 2003

A comparison was made of the estimates of the outputs of nitrogen (N) in faeces and urine on Awassi ewes using two methods: (1) conventional collection in digestibility crates, with urine acidified to prevent volatilization (separation method); (2) collection of both faeces and urine together in bags placed over the tail of the ewe and using the ratio between N and acid detergent fibre (ADF) in samples taken from the rectum to partition the total N output between faeces and urine (N:ADF method). The comparison was made on eight ewes in a crossover design using three collection periods of 5 d. There were no significant differences between the methods in the estimates of nitrogen in urine and faeces, although differences between methods in the estimation of total N output were close to being significant. The precision of the estimates was lower with the N:ADF method.
Laparoscopic dissection of intact ovarian dermoid cysts: evaluation of a simple technique
Authors: Remorgida V. , Anserini P. , Magnasco A. , Capitanio G.L.
Published: November 2003

Objective to evaluate a simple laparoscopic technique for dissecting ovarian dermoid cysts without any risks of puncture and spillage.

Design Open clinical study.

Setting University hospital.

Subjects 10 premenopausal women with unilateral dermoid cysts operated between October 1993 and November 1994.

Interventions Laparoscopic technique based on: (a) creation of a cleavage plane between the cyst and the ovary by fluid injection with a laparoscopic injection needle; (b) dissection of the cyst by a combination of water, scissors and gravity without direct traction on the cyst (c) vaginal extraction by a specific device after cyst placement inside a laparoscopic bag.

Results Mean cyst diameter was 6 cm (range 3–10). Mean operating time was 105 min (range 50–160). All patients were discharged 24 h after surgery. The dermoid cysts were dissected intact from the ovary and extracted without spillage from the abdominal cavity in all cases.

Conclusions Using a careful technique, it is possible to prevent rupture and spillage of dermoid cysts during laparoscopic surgery.
Postoperative pain and postoperative recovery following respective laparoscopy: no relation to the intra‐abdominal surgical procedure
Authors: Mais V. , Ajossa S. , Guerriero S. , Peiretti R.F. , Serri F. , Melis G.B.
Published: November 2003

Objective To investigate whether different resective procedures might be related to different intensities of postoperative pain and different subjective recovery times following laparoscopic surgery

Interventions A total of 60 patients underwent laparoscopic myomectomy, 60 patients underwent laparascopic excision of endometriomas, and 60 patients underwent laparoscopic enucleation of non‐endometriotic adnexal cysts.

Measures The intensity of postoperative pain was assessed by completion of a visual analogue scale on the day of surgery and 1, 2, and 3 days postoperatively, and the results of the three groups were compared. We also compared the proportions of patients who were analgesic free on day 2, discharged from hospital within 3 days, and feeling fully recuperated on day 15.

Results No differences were found among the three groups of patients.

Conclusions Both the intensity of postoperative pain and the length of convalescence following resective laparoscopy do not seem to depend on the intra‐abdominal surgical procedure.
A novel approach for the repair of an incisional hernia following laparoscopic hysterectomy
Authors: Tsaltas J. , Lolatgis N. , Lawrence A.S. , Healy D.L. , Moohan J.
Published: November 2003

With the more frequent use of trocars of 10 mm or more in size, there has been an increase in reports of herniation of bowel and other intra‐abdominal structures at these trocar sites. A novel technique for the repair of these defects using the Verres needle is described.
Laparoscopically instilled fluid: the rate of absorption and the effects on patient discomfort and fluid balance
Authors: Hart R. , Magos A.
Published: November 2003

The aim of the study was to assess the length of time laparoscopically instilled fluid remains in the peritoneal cavity and to assess its effects on patient discomfort and fluid balance. The setting was a London teaching hospital, and randomized controlled design was used. A total of 24 women undergoing laparoscopic surgery were randomized, one group (n = 12) received 1 l of normal saline instilled into the pouch of Douglas at the end of surgery, and the other (n = 12) acted as controls. A vacuum drain was left clamped at the end of surgery and was released after 2, 4, 8, or 16 h to determine the rate of fluid absorption. Overall fluid balance and analgesic requirements were assessed along with the subjective symptoms of thirst and pain. All of the fluid was absorbed after approximately 16 h. The control group passed significantly less urine (P = 0.046) despite having a similar fluid intake. The experimental group required significantly less intramuscular analgesia (P = 0.040) and required shorter hospitalization (P = 0.029) than the control group. Differences in thirst and pain scores did not reach statistical significance. Intraperitoneal fluid appears to decrease postoperative discomfort and can act as a source of postoperative rehydration.
THE DIAGNOSTIC ACCURACY OF A 1.2‐mm MINILAPAROSCOPE
Authors: Barisic D. , Strelec M. , Van Der Ven H. , Prietl G.
Published: November 2003

Objective To evaluate the diagnostic suitability of a fibreoptic minilaparoscope with a diameter of 1.2 mm. Design Laparoscopy was performed under general anaesthesia, first with a 1.2‐mm minilaparoscope, and then immediately with a conventional 10‐mm laparoscope. The findings obtained by minilaparoscopy were compared with those obtained by conventional laparoscopy. Setting Two university‐based hospitals. Subjects These were 20 patients, whose ages ranged from 16 to 40 years, and body weight from 52 to 115kg. Laparoscopy was performed because of infertility (13 patients), chronic pelvic pain (2), suspected ectopic pregnancy (2), sterilization (1) and for laparoscopic surveillance during operative hysteroscopy (2). Results The visualization of pelvic organs with the minilaparoscope was acceptable, although the size of the video image was smaller when compared with that from a 10‐mm telescope. Pelvic findings obtained by minilaparoscopy coincided with those on conventional laparoscopy in 17 patients. Small endometriotic implants in the anterior cul‐de‐sac, as well as white fibrotic endometriotic plaques in the pouch of Douglas, were misinterpreted in three patients. Adhesions, distal tubal occlusions, small fibroids, hydatid cysts, and tubal pregnancies were correctly diagnosed by minilaparoscope. No complications occurred in any of the 20 patients. Conclusions The 1.2‐mm fibreoptic telescope, introduced through the Veress needle, may be useful for diagnostic procedures.
THE EFFECT OF SORBITOL–MANNITOL ABSORPTION ON SERUM SODIUM CONCENTRATION DURING HYSTEROSCOPIC SURGERY
Authors: Barisic D. , Wamsteker K. , Strelec M. , Cvrk L. , Babic D.
Published: November 2003

Objective To evaluate the effect on serum electrolyte concentrations of sorbitol–mannitol absorption during hysteroscopic surgery.

Design The volume of sorbitol–mannitol retained during hysteroscopic surgery and the difference between the preoperative and the postoperative serum sodium concentrations were measured and analysed for correlation.

Setting A university‐based hospital.

Subjects These were 40 consecutive patients undergoing hysteroscopic resection of submucous fibroid or uterine septum, using a 9‐mm continuous flow resectoscope with loop or needle electrode for high‐frequency cutting and coagulation and a 4% sorbitol–mannitol solution for uterine irrigation.

Results The mean volume of infused sorbitol–mannitol solution was 5435 ± 720 ml (mean ± SEM), with a mean fluid deficit of 718 ± 120 ml. The fall in serum sodium concentration correlated positively with the sorbitol–mannitol deficit (r=0.79, P<0.001), and with the total volume of infused sorbitol–mannitol (r=0.45, P<0.01). In 26 patients the sorbitol–mannitol deficit was less than 1000 ml, and in 14 patients it was equal to or higher than 1000 ml. The group with a fluid deficit exceeding 1000 ml had a significantly (P<0.001) higher fall in serum sodium concentration. Type I or type II fibroid patients retained a significantly (P< 0.001) higher volume of sorbitol–mannitol and had a significantly (P<0.005) higher fall in serum sodium concentration than the group of patients who had a septum or a type 0 fibroid resected. The two patients with a type II fibroid resected retained 2000 ml and 3800 ml of sorbitol–mannitol solution. One of them had symptoms of water intoxication and dilutional hyponatraemia, with cerebral and pulmonary oedema, and the other had signs of early pulmonary oedema. Both patients were successfully managed.

Conclusions The fall in serum sodium concentration is positively correlated to the sorbitol–mannitol deficit. Type II fibroid patients are at the highest risk of excessive fluid intravasation and consequent dilutional hyponatraemia. A routine postoperative measurement of serum sodium concentration when fluid deficit exceeds 1000 ml is recommended.
DIAGNOSIS AND THERAPY OF ADNEXAL MASSES IN POSTMENOPAUSAL WOMEN: A PROSPECTIVE STUDY
Authors: Hesseling M , De Wilde R.L.
Published: November 2003

Objectives This prospective study was conducted to examine the safety and efficacy of the operative laparoscopic management of adnexal masses in the postmenopause and to define the limits of this procedure.

Main outcome measure The parameter chosen for testing the preoperative diagnostic model was the laparoscopic operation of a malignant ovarian tumour.

Design This hospital‐based study included 265 consecutive postmenopausal patients with adnexal masses. After preoperative pelvic examination, transvaginal/abdominal ultrasound and determination of the tumour marker CA 125, primary laparoscopy was performed in 69.4% (group A) and primary laparotomy in 30.6% (group B). In 4.2% the patients were converted to laparotomy following diagnostic endoscopy (group Ab); in 65.2% the operative laparoscopic adnectomy was completed (group Aa).

Results In the total sample, 81.1% of the tumours were classified as definitely benign, 3.8% showed borderline changes and 15.1% were malignant. The malignancy rate in group A was 3.8% with 2.2% in group Ab, and in group B it was 53.1%. Complications occured in 1.9% of cases, without statistically significant differences between the two groups.

Conclusion By combining pelvic examination, transvaginal/abdominal ultrasound, determination of the tumour marker CA 125, and adequate intraoperative evaluation during laparoscopy, the risk of laparoscopic operation of a malignant adnexal tumour can be reduced to a minimum. After carefully weighing up the benefits and risks, we consider a laparoscopic approach to be justified in a selected patient population in the postmenopause, provided the team has sufficient experience in the preoperative assessment of adnexal masses.
Survey of training in minimal access surgery in the West Midlands region of the UK
Authors: Chin K. , Newton J.
Published: November 2003

Objective To assess the status of trainees in the West Midlands, UK, their minimal access surgery (MAS) operative experience, level of supervision, complications experienced, and mode of training in MAS.

Design Postal survey utilizing a structured questionnaire.

Setting Gynaecology units throughout the West Midlands.

Subjects A total of 167 gynaecology trainees.

Main outcome measures Types of complications related to level of supervision and mode of training.

Results The response rate was 72% (n = 120). Only 25% of these trainees had attended a formal training course. Of the trainees, 36% and 26% had encountered laparoscopic and hysteroscopic complications, respectively, in their total experience. Bowel injury was four times more likely to have been caused by those who were unsupervised and almost three times more likely to have been caused by those who had not been on a formal training course (P < 0.005).

Conclusion This study supports the strong link between supervision, appropriate training and complications in MAS and stresses the crucial role of the supervisor and the need for formal training.
Pregnancy outcome following endometrial ablation
Authors: Edwards A. , Tippett C. , Lawrence M. , Tsaltas J.
Published: November 2003

Objective We report a case of successful outcome in a pregnancy following endometrial ablation. We also review the 10 previous reported pregnancies following this procedure and try to suggest guidelines for the management of this condition, based upon the cases reported to date and by drawing from the clinicopathologically related condition Asherman's syndrome.

Outcome The case reported in this paper had a successful outcome with minimal intervention. The patient became pregnant following an ablation that had achieved excellent symptom relief of her menorrhagia.

Conclusion Although our case had a succesful outcome with minimal intervention, ideally pregnancy following endometrial ablation should be avoided. Pregnancies following endometrial ablation should continue to be reported to allow the establishment of a database to ascertain the real risk of pregnancy and third‐stage problems. This will assist practitioners with management and in counselling their patients.
Air embolism during endoscopic resection of the endometrium: recommendations for a change in practice
Authors: Overton C. , Wilson‐Smith E. , Hunt P. , Hackman B.
Published: November 2003

A case of venous air embolism complicating endometrial resection is presented.
HYSTEROSCOPY: A MILESTONE IN GYNAECOLOGY
Authors: Gaglione R. , Cinque B. , Paparatti L. , Pistilli E.
Published: November 2003

Objective The aim is to stress the fundamental role of hysteroscopy in the diagnosis of the cause of endometrial pathologies.

Subjects and methods The results of 10 years’ experience, between December 1984 and January 1995, in the gynaecological endoscopy outpatients' unit of the Catholic University of Rome are reported. A series of 6180 women undergoing diagnostic hysteroscopy is analysed and the indications, contraindications and side‐effects of hysteroscopic examination are discussed.

Results Outpatients, mean age of 51 years (range 22–81), who underwent hysteroscopic examination had, as main indication, abnormal uterine bleeding (AUB). The differing distributions of hysteroscopic findings in pre‐ and postmenopausal women is stressed, along with the importance of focal endometrial pathologies such as polyps and submucosal myomas in premenopause, the high incidence of endometrial atrophy, and the significant occurrence of hyperplastic and neoplastic hysteroscopic findings in the postmenopause. Primary and secondary infertility are, after AUB, the second most common indications for hysteroscopic examination, and the role of malformation (septate and subseptate uterus), inflammation (intrauterine synechiae) and focal endometrial pathologies (polyps and submucosal myomas) is illustrated.

Conclusions As a result of the introduction of hysteroscopy it is now possible to preserve organs, with the slight trauma of noninvasive treatment, rather than using extirpartive surgery. In premenopausal women with AUB (n=2132) the most frequent pathologies were low‐risk hyperlasia (25.3%), submucosal myoma (24.5%) and endometrial polyps (8.3%); there were normal findings in 40.2%. There is a low incidence of high‐risk hyperplasia (0.7%) and neoplastic pathology (0.5%). In postmenopausal women with AUB there is a high incidence of atrophy (23%), whereas high‐risk hyperplasia and neoplastic pathology are five and eight times more common, respectively, in these women than in premenopausal patients.
Intraoperative autologous blood transfusion in laparoscopic surgery for ectopic pregnancy
Authors: Yamada T. , Yamashita Y. , Terai Y. , Okuda K. , Sugimoto O.
Published: November 2003

Objective Our purpose was to evaluate the safety, efficacy and procedural difficulties of intraoperative autologous blood transfusion during laparoscopic surgery for ectopic pregnancy.

Design A retrospective study was performed.

Methods The Cell Saver, an intraoperative autologous blood salvage device, was used in laparoscopic operations on 13 patients with ectopic pregnancy, who had haemoperitoneum but good physical status without severe anaemia and hypovolaemic shock.

Results Homologous blood transfusion was not needed in any patient. The mean blood loss was 327±178 ml and the mean volume of reinfused processed blood was 288±92 ml. The haemoglobin level of reinfused processed blood was proportional to the blood loss. Neither adverse reactions to norprocedural difficulties of autotransfusion were observed.

Conclusions When laparoscopic surgery is performed for ectopic pregnancy in patients with haemoperitoneum, intraoperative autologous transfusion employing the Cell Saver is considered to be a potentially very useful technique.
Intrauterine adhesions and fertility: results of hysteroscopic treatment
Authors: Roge P. , Cravello L. , D'Ercole C. , Brousse M. , Boubli L. , Blanc B.
Published: November 2003

Objective

To assess the efficacy of hysteroscopic surgery in infertile women presenting with uterine synechiae.

Design

A retrospctive audit of 52 patients.

Setting

University hospital.

Subjects

A total of 52 patients presenting with intrauterine adhesions in a context of reproductive dysfunction: infertility, 29 cases; recurrent abortions, 23 cases.

Interventions

Operative hysteroscopy including section with scissors, lesion division, and electrosection.

Results

There were 34 pregnancies in 28 patients, with 24 term deliveries and 10 abortions.

Conclusion

Operative hysteroscopy should be considered as the primary treatment for patients with intrauterine adhesions. Hysteroscopy allows selectivity, reproducibility with little morbidity, and preserves the surrounding endometrium. After several unsuccessful procedures, abdominal surgery could be proposed.