bluuebunny/crossref_metadata_2025 huggingface dataset:
Whole‐gut transit rates and wet stool weight in an urban Nigerian population
Authors: Ogunbiyi T. A. J.
Published: April 2005

The objective of this study was to test the “dietary fiber theory of Western diseases” in Lagos, an area of relatively low prevalence, by investigating the relationship between fiber in diet, stool weight, and whole‐gut transit rates in a sample of the population on an urban‐type diet. A 5‐day study of fiber in diet and stool weight in 9 normal subjects showed a positive correlation between stool weight and consumed fiber. A second 5‐day study of the diet, whole‐gut transit rates, and wet stool weight in 37 male students revealed that only 15% of the lunches and dinners consisted of staple foods rich in crude fiber, that the mean transit time for first marker was 24.8 hours (SD±10.8) and for 80% of the markers was 48.5 hours (SD±20.9), and that the mean stool weight was 143.3 gram (SD±48.5). There was a negative correlation between transit time and wet stool weight both for first and 80% of markers. The transit time was slower and the stool weight less than figures quoted for rural Africans, but was not significantly different from British figures. The consequences of adopting a sophisticated low fiber diet due to urbanization in rapidly developing urban communities are discussed. It is suggested that in order to prevent an increase in the incidence of colorectal “Western diseases,” a health education drive in urban areas highlighting the qualities of high fiber staple foods be instituted.
Chemical dissolution of bile duct stones
Authors: Allen Bruce L. , Deveney Clifford W. , Way Lawrence W.
Published: April 2005

Chemical dissolution of retained ductal stone(s) is recommended when mechanical extraction through the formed T‐tube tract fails. Sodium cholate solution has been most widely used for infusion, and two‐thirds of patients can be successfully treated. A new agent, the medium chain glyceride mono‐octanoin, is more potent in vitro and the results of early clinical trials are encouraging. The use of oral longterm chenodeoxycholic acid for treatment of nonobstructing asymptomatic ductal stones has been successful in 50% of a small number of patients.
Results of endoscopic papillotomy: A collective experience from nine endoscopic centers in West Germany
Authors: Reiter Jürgen J. , Bayer Hans P. , Mennicken C. , Manegold Bernd C.
Published: April 2005

This is a report of 1,403 patients who underwent endoscopic papillotomy (EPT) in 9 endoscopic centers in West Germany from 1973 up to April 1, 1977. The main indication for EPT was stones in the bile ducts causing obstructive jaundice. In 79.5% of the patients, a previous surgical operation on the bile ducts had been done, and in 20.5%, the gallbladder was still present. Other indications for EPT were benign and malignant stenosis of the duodenal papilla, and cholangitis in the blind sack syndrome associated with an existing choledochoduodenostomy. The complication rate of EPT was 7.3%. The main complications were pancreatitis, cholangitis, hemorrhage, and perforation. Incarceration of stones or instruments was rare. Most complications could be treated conservatively. The mortality rate at 1.5% was low, and less than that of transduodenal papillotomy. Late complications that occur after transduodenal papillotomy were not found and should not occur after EPT. EPT eliminates the need for laparotomy and represents an alternative for the aged patient in poor general condition.
Follow‐up of 100 patients five to eight years after parietal cell vagotomy
Authors: Jensen Hans‐Eric , Amdrup Erik
Published: April 2005

Recurrent ulcer developed in 9 out of 100 patients followed up for 5 to 8 years after parietal cell vagotomy (PCV) for duodenal ulcer. The time of recurrence was often surprisingly late, the latest occurring in the 6th year. Patients with recurrence did not differ significantly from the total group of patients with respect to sex, preoperative age, weight, or gastric acid secretion. Patients with recurrent ulcer were evenly distributed among the surgeons who performed the operations, and showed no obvious difference in reduction in spontaneous or in pentagastrin‐ and insulin‐stimulated acid secretion, compared to the symptom‐free patients. In 3 patients recurrence might have been related to abuse of salicylates and tobacco, and possibly to mental stress. These ulcers healed in response to nonsurgical treatment and the patients have remained symptom free for several years. In 6 patients, antrectomy was required. Sequelae occurred very infrequently, but in 1 patient dumping complaints were severe. An overall clinical assessment by Visick grading placed 72 patients in grade I, 14 in grade II, 4 in grade III, and 10 in grade IV. The failures included 6 patients who required reoperation for recurrent ulcer, 2 who required reoperation for gastric stasis, and the patient with severe dumping.
Surgical treatment of gastroesophageal reflux and its complications
Authors: Woodward E. R.
Published: April 2005

Although most patients with reflux peptic esophagitis have the sliding type of hiatal hernia, correction of the hernia is incidental and the objective of the surgeon is to reestablish continence of the lower esophageal sphincter (LES). The presence of this crucial closure mechanism between the stomach and esophagus was demonstrated just over 2 decades ago by manometric and cineradiographic studies of the esophagogastric junction. Although the abdominal location of the LES exerts a favorable influence, it is possible to have normal LES function in the supradiaphragmatic position, and the relationship between the sliding hiatal hernia and reflux peptic esophagitis remains unclear. Some patients develop esophagitis in the absence of a hernia.

Three surgical methods are in common use today for correcting gastroesophageal reflux: the Belsey cardioplasty, the Nissen fundoplication, and the Hill posterior gastropexy. Results have been analyzed on the basis of clinical, anatomic, and physiologic success. The Nissen fundoplication is the most certain to correct reflux and, as an added advantage, can be performed by either the thoracic or abdominal approach. However, it is associated with the highest incidence of chronic side effects, particularly the “postfundoplication” or “gas‐bloat syndrome.” The Hill procedure can be accomplished only through the abdomen and is associated with a somewhat higher incidence of recurrent esophagitis and recurrent hernia. However, side effects are minimal. The Belsey cardioplasty has the advantage of requiring a minimum of available tissue for its successful accomplishment. However, it can be performed with ease only by the thoracic approach and also has a relatively high incidence of recurrent or persistent esophagitis.

For these reasons, we prefer the Hill posterior gastropexy in the medically intractable, but otherwise uncomplicated, patient with reflux peptic esophagitis. The Nissen fundoplication is preferred for cases complicated by prior unsuccessful surgery, stenosis with short esophagus, and marked obesity. The Belsey cardioplasty is most useful in patients who have had extensive prior gastric surgery with loss of available tissue for repair. The combined Thal patch‐Nissen fundoplication is considered the primary treatment of choice in patients with transmural strictures of the esophagus, particularly because it is associated with a low morbidity and mortality.
Operative treatment of recurrence after vagotomy and drainage for duodenal ulcer, gastric ulcer, and acid dyspepsia without ulcer
Authors: Johnson Jon A. , Giercksky Karl‐Erik
Published: April 2005

Fifty‐two operations were performed on 44 patients with recurrent disease after vagotomy and drainage (38) or vagotomy without drainage (6). The initial vagotomy was done for duodenal ulcer (23), gastric ulcer (17), and acid dyspepsia without ulcer (4). The reoperations were 31 revagotomies, 11 Billroth II gastric resections, 2 gastrojejunostomies, and later 4 gastric resections for another recurrence, 2 gastrojejunostomies for retention, and 2 operations for dumping. After an observation period of 1 to 6 years (mean 2.5 years), the results were good in 22 patients, satisfactory in 20 and unsatisfactory in 2 patients. Of 42 patients with recurrent disease, 41 showed a significant increase of acid output during insulin stimulation before operative treatment of the recurrence. Of 31 revagotomized patients, 26 were insulin‐test negative without later signs of recurrence. Five patients remained insulintest positive, and 4 of these required gastric resection for another recurrence. This series demonstrates the therapeutic significance of complete vagotomy, and emphasizes the value of the insulin test for evaluation of the completeness of the vagotomy.
Dextran in the prophylaxis of pulmonary embolism
Authors: Bergentz Sven ‐Erik
Published: April 2005

Dextran is a plasma volume expander which has antithrombotic effects. Some of these effects may be nonspecific and due to hemodilution and venous flow improvement. However, dextran also has specific antithrombotic effects that cause a temporary change in the structure and function of Factor VIII (antihemophilic globulin), which results in a decrease in platelet aggregability and thrombus stability. Intravenous dextran therapy has no marked effect on the incidence of small, early postoperative thrombi as detected by125Iodine‐fibrinogen, but it produces a significant decrease in the incidence of thrombi that can be diagnosed phlebographically or clinically. The most marked effect of dextran is on pulmonary emboli, and particularly on fatal pulmonary emboli as seen at autopsy, where it produces about a fivefold decrease in incidence.

It is concluded that the antithrombotic properties of dextran are particularly useful in decreasing the incidence of postoperative pulmonary emboli.
Comparative value of tests for the diagnosis of venous thrombosis
Authors: Hirsh Jack , Hull Russell
Published: April 2005

The clinical diagnosis of venous thrombosis lacks sensitivity and specificity. Venography is recognized as the diagnostic reference standard but is invasive and associated with patient morbidity.125I‐fibrinogen leg scanning is sensitive to calf vein thrombosis but is relatively insensitive to femoral vein thrombosis and does not detect iliac vein thrombosis. This test is most useful as a screening test in high‐risk medical and surgical patients. The test may be falsely positive at the site of hematoma, and because of this, it has serious limitations in patients undergoing knee and hip surgery. Leg scanning also has limitations when used to diagnose patients with suspected venous thrombosis because it may take up to 72 hours to obtain a positive result. Impedance plethysmography (IPG), a noninvasive technique, is sensitive and specific for thrombosis involving the popliteal, femoral, and iliac veins. Combined with125Ifibrinogen leg scanning, this test has considerable potential as a screening test in patients undergoing hip surgery. The combined use of IPG and leg scanning has also been shown to be highly accurate for the diagnosis of clinically suspected venous thrombosis, and this approach offers a less invasive alternative to venography in these patients. The Doppler ultrasound flowmeter, like the IPG, is sensitive to popliteal and more proximal vein thrombosis but is relatively insensitive to calf vein thrombosis. The interpretation of the results of this test is more subjective and much more dependent upon the expertise of the examiner than is the IPG. A number of other techniques, including image scanning, and themography, are under investigation but require further evaluation before they can be recommended in the management of patients with venous thromboembolism.
Hemorrhage from the large bowel with special reference to angiodysplasia and diverticular disease
Authors: Welch Claude E. , Athanasoulis Christos A. , Galdabini James J.
Published: April 2005

A series of 72 patients with bleeding either from angiodysplasia or diverticular disease of the colon has been studied in the Massachusetts General Hospital. Modern angiographic techniques have dispelled much of the mystery and reduced the mortality of colonic bleeding. In this series 85% of the bleeding originated from the right or transverse colon. Of the 72 patients, 70 survived; there were 52 operations. The 2 deaths occurred in an 81‐year‐old patient after subtotal colectomy and an 84‐year‐old patient after right colectomy, both for diverticular bleeding. After discharge from the hospital, 67 patients have been followed up for a median interval of 22 postoperative months. Late follow‐up of patients with bleeding from either angiodysplasia or diverticula showed that segmental resection was successful in stopping bleeding in 38 of 42 patients (90%); the 10 patients who had subtotal colectomy had no recurrent bleeding.

The choice of operation must depend upon many factors that reflect operative risks, which must be balanced against better control of bleeding by subtotal colectomy. Because a right colectomy for angiodysplasia has been followed by recurrent bleeding in 4 of 31 cases, it is suggested that the right half of the transverse colon be included in the right colectomy since this will introduce no greater hazard and may lead to better control of bleeding. Subtotal colectomy is the operation of choice for bleeding from the colon from an unknown source, in good‐risk patients with widespread diverticulosis involving all segments of the colon, and for a combination of angiodysplasia on the right and extensive diverticular disease on the left. In poor‐risk patients, if either angiodysplasia or a single bleeding point has been demonstrated by selective arteriography, a segmentai resection of that area will be the safest procedure.
Seasonal variations of equatorial spread-F
Authors: Subbarao K. S. V. , Krishna Murthy B. V.
Published: April 2005

Abstract. The occurrence of spread-F at Trivandrum (8.5°N, 77°E, dip 0.5°N) has been investigated on a seasonal basis in sunspot maximum and minimum years in terms of the growth rate of irregularities by the generalized collisional Rayleigh-Taylor (GRT) instability mechanism which includes the gravitational and cross-field instability terms. The occurrence statistics of spread-F at Trivandrum have been obtained using quarter hourly ionograms. The nocturnal variations of the growth rate of irregularities by the GRT mechanism have been estimated for different seasons in sunspot maximum and minimum years at Trivandrum using h'F values and vertical drift velocities obtained from ionograms. It is found that the seasonal variation of spread-F occurrence at Trivandrum can, in general, be accounted for on the basis of the GRT mechanism.
Characteristics and distribution patterns of snow and meteoric ice in the Weddell Sea and their contribution to the mass balance of sea ice
Authors: Eicken Hajo , Lange Manfred A. , Wadhams Peter
Published: April 2005

Abstract. Based on snow- and ice-thickness measurements at >11 000 points augmented by snow- and icecore studies during 4 expeditions from 1986 - 92 in the Weddell Sea, we describe characteristics and distribution patterns of snow and meteoric ice and assess their importance for the mass balance of sea ice. For first-year ice (FY) in the central and eastern Weddell Sea, mean snow depth amounts to 0.16 m (mean ice thickness 0.75 m) compared to 0.53 m (mean ice thickness 1.70 m) for second-year ice (SY) in the northwestern Weddell Sea. Ridged ice retains a thicker snow cover than level ice, with ice thickness and snow depth negatively correlated for the latter, most likely due to aeolian redistribution. During the different expeditions, 8, 15, 17 and 40% of all drill holes exhibited negative freeboard. As a result of flooding and brine seepage into the snow pack, snow salinities averaged 4‰. Through 18O measurements the distribution of meteoric ice (i.e. precipitation) in the sea-ice cover was assessed. Roughly 4% of the total ice thickness consist of meteoric ice (FY 3%, SY 5%). With a mean density of 290 kg/m3, the snow cover itself contributes 8% to total ice mass (7% FY, 11% SY). Analysis of ∆18O in snow indicates a local maximum in accumulation in the 65 to 75°S latitude zone. Hydrogen peroxide in the snow has proven useful as a temporal tracer and for identification of second-year floes. Drawing on accumulation data from stations at the Weddell Sea coast, it becomes clear that the onset of ice growth is important for the evolution of ice thickness and the interaction between ice and snow. Loss of snow to leads due to wind drift may be considerable, yet is reduced owing to metamorphic processes in the snow column. This is confirmed by a comparison of accumulation data from coastal stations and from snow depths over sea ice. Temporal and spatial accumulation patterns of snow are shown to be important in controlling the sea-ice cover evolution.
The impact of cloud inhomogeneities on the Earth radiation budget: the 14 October 1989 I.C.E. convective cloud case study
Authors: Parol F. , Buriez J. C. , Crétel D. , Fouquart Y.
Published: April 2005

Abstract. Through their multiple interactions with radiation, clouds have an important impact on the climate. Nonetheless, the simulation of clouds in climate models is still coarse. The present evolution of modeling tends to a more realistic representation of the liquid water content; thus the problem of its subgrid scale distribution is crucial. For a convective cloud field observed during ICE 89, Landsat TM data (resolution: 30m) have been analyzed in order to quantify the respective influences of both the horizontal distribution of liquid water content and cloud shape on the Earth radiation budget. The cloud field was found to be rather well-represented by a stochastic distribution of hemi-ellipsoidal clouds whose horizontal aspect ratio is close to 2 and whose vertical aspect ratio decreases as the cloud cell area increases. For that particular cloud field, neglecting the influence of the cloud shape leads to an over-estimate of the outgoing longwave flux; in the shortwave, it leads to an over-estimate of the reflected flux for high solar elevations but strongly depends on cloud cell orientations for low elevations. On the other hand, neglecting the influence of cloud size distribution leads to systematic over-estimate of their impact on the shortwave radiation whereas the effect is close to zero in the thermal range. The overall effect of the heterogeneities is estimated to be of the order of 10 W m-2 for the conditions of that Landsat picture (solar zenith angle 65°, cloud cover 70%); it might reach 40 W m-2 for an overhead sun and overcast cloud conditions.
Sensitivity of the French Alps snow cover to the variation of climatic variables
Authors: Martin E. , Brun E. , Durand Y.
Published: April 2005

Abstract. In order to study the sensitivity of snow cover to changes in meteorological variables at a regional scale, a numerical snow model and an analysis system of the meteorological conditions adapted to relief were used. This approach has been successfully tested by comparing simulated and measured snow depth at 37 sites in the French Alps during a ten year data period. Then, the sensitivity of the snow cover to a variation in climatic conditions was tested by two different methods, which led to very similar results. To assess the impact of a particular "doubled CO2" scenario, coherent perturbations were introduced in the input data of the snow model. It was found that although the impact would be very pronounced, it would also be extremely differentiated, dependent on the internal state of the snow cover. The most sensitive areas are the elevations below 2400 m, especially in the southern part of the French Alps.
Methods of detection and estimation errors in ST radar studies
Authors: Ferrat S. , Crochet M.
Published: April 2005

Abstract. The classical theory of detection using the Neyman-Pearson principle is applied to stratosphere-troposphere (ST) radar signals. It is extended to provide information regarding the detection of weak signals which complements the detectability method usually employed in ST radar studies. It is shown that for ST radar signals of low amplitude and a detectability around 3 (a value commonly invoked in literature), the probability of detection is about equal to the probability of false alarm. The question of threshold detectability is also discussed. Spectral moments errors are evaluated by a method which is an extension of the analytical method of estimation developed by Miller and Rochwarger and the results compared to other statistical and analytical models. As already known, three factors can affect the error on the estimated parameters: the signal-to-noise ratio, the spectral width and the incoherent integration number. For high signal-to-noise ratios, analytical results are in good agreement with Barrick's and Denenberg's theoretical models and with Yamamoto's statistical one. For low signal-to-noise ratios, the spectral parameters are more sensitive to the selected model but overall variability is similar.
EISCAT observations of unusual flows in the morning sector associated with weak substorm activity
Authors: Fox N. J. , Lockwood M. , Cowley S. W. H. , Freeman M. P. , Friis-Christensen E. , Milling D. K. , Pinnock M. , Reeves G. D.
Published: April 2005

Abstract. A discussion is given of plasma flows in the dawn and nightside high-latitude ionospheric regions during substorms occurring on a contracted auroral oval, as observed using the EISCAT CP-4-A experiment. Supporting data from the PACE radar, Greenland magnetometer chain, SAMNET magnetometers and geostationary satellites are compared to the EISCAT observations. On 4 October 1989 a weak substorm with initial expansion phase onset signatures at 0030 UT, resulted in the convection reversal boundary observed by EISCAT (at ~0415 MLT) contracting rapidly poleward, causing a band of elevated ionospheric ion temperatures and a localised plasma density depletion. This polar cap contraction event is shown to be associated with various substorm signatures; Pi2 pulsations at mid-latitudes, magnetic bays in the midnight sector and particle injections at geosynchronous orbit. A similar event was observed on the following day around 0230 UT (~0515 MLT) with the unusual and significant difference that two convection reversals were observed, both contracting poleward. We show that this feature is not an ionospheric signature of two active reconnection neutral lines as predicted by the near-Earth neutral model before the plasmoid is "pinched off", and present two alternative explanations in terms of (1) viscous and lobe circulation cells and (2) polar cap contraction during northward IMF. The voltage associated with the anti-sunward flow between the reversals reaches a maximum of 13 kV during the substorm expansion phase. This suggests it to be associated with the polar cap contraction and caused by the reconnection of open flux in the geomagnetic tail which has mimicked "viscous-like" momentum transfer across the magnetopause.
A case study of storm commencement and recovery plasmaspheric electric fields near L=2.5 at equinox
Authors: Balmforth H. F. , Clilverd M. A. , Smith A. J.
Published: April 2005

Abstract. Data from the VLF Doppler experiment at Faraday, Antarctica (65° S, 64° W) are used to study the penetration of the high-latitude convection electric field to lower latitudes during severely disturbed conditions. Alterations of the electric field at L-values within the range 2.0 - 2.7 are studied for two cases at equinox (10 - 12 September 1986 and 1 - 3 May 1986). The recovery of the electric field is found to be approximately an exponential function of time. Values for the equatorial meridional E×B drift velocity, inferred from the data, are used as inputs to a model of the plasmasphere and ionosphere. The model and experimental results are used to investigate the post-storm alteration of ionospheric coupling processes. The magnitude of the effect of ionosphere-plasmasphere coupling fluxes on NmF2 values and the O+-H+ transition height is dependent on the local time of storm commencement, and on the orientation of the electric field. The coupling fluxes appear to have a maximum influence on ionospheric content during the main phase of geomagnetic activity that produces outward motion of plasmaspheric whistler ducts.
On Ps6 and longer period geomagnetic pulsations in the Indian equatorial region
Authors: Rao D. R. K. , Asinkar R. L.
Published: April 2005

Abstract. Adopting an appropriate procedure suitable for processing the amplitude-time records based on the two-component spectral analysis technique, the statistical information on Ps6 and other longer periods are worked out on the geomagnetic field registrations in the Indian longitudinal regions at and away from the equatorial electrojet influence. The storm interval during 21 and 22 September 1982 has been chosen for the analysis, as violent and regular cyclic variations of the geomagnetic field were recorded in all the three components of the field at the Indian observatories. The procedure, when applied to two intervals of afternoon and night conditions of equatorial ionosphere, showed practically the same polarisation characteristics in the H-D plane at all the frequencies under the equatorial electrojet. At far away places from this influence, the ellipticities are found to be relatively to the west during the afternoon. These, along with the other results, are discussed.
Theoretical validation of ground-based microwave ozone observations
Authors: Ricaud P. , Brasseur G. , Brillet J. , de La Noë J. , Parisot J.-P. , Pirre M.
Published: April 2005

Abstract. Ground-based microwave measurements of the diurnal and seasonal variations of ozoneat 42±4.5 and 55±8 km are validated by comparing with results from a zero-dimensional photochemical model and a two-dimensional (2D) chemical/radiative/dynamical model, respectively. O3 diurnal amplitudes measured in Bordeaux are shown to be in agreement with theory to within 5%. For the seasonal analysis of O3 variation, at 42±4.5 km, the 2D model underestimates the yearly averaged ozone concentration compared with the measurements. A double maximum oscillation (~3.5%) is measured in Bordeaux with an extended maximum in September and a maximum in February, whilst the 2D model predicts only a single large maximum (17%) in August and a pronounced minimum in January. Evidence suggests that dynamical transport causes the winter O3 maximum by propagation of planetary waves, phenomena which are not explicitly reproduced by the 2D model. At 55±8 km, the modeled yearly averaged O3 concentration is in very good agreement with the measured yearly average. A strong annual oscillation is both measured and modeled with differences in the amplitude shown to be exclusively linked to temperature fields.
Spatial variability of the aspect sensitivity of VHF radar echoes in the troposphere and lower stratosphere during jet stream passages
Authors: Yoe J. G. , Czechowsky P. , Rüster R. , Schmidt G.
Published: April 2005

Abstract. The aspect sensitivity of SOUSY-VHF-radar oblique-beam echoes from the troposphere and lower stratosphere has been examined for a number of jet stream passages during the years 1990 - 1992. When the core of the jet is overhead or nearly so, vertical profiles of the aspect sensitivity display two notable features. First, the distinction between mainly isotropic and strongly aspect-sensitive echoes in the troposphere and the lower stratosphere, respectively, often reported for measurements made during calm conditions, does not necessarily prevail in the vicinity of the jet stream. Second, echoes obtained at altitudes near the height of the horizontal wind maximum are found to be more aspect sensitive for beams directed parallel to the horizontal flow or nearly so, than for other beam directions. It is demonstrated that time-averaged horizontal wind speeds estimated from the radar data, taking into account the reduced effective oblique-beam zenith angle resulting from aspect sensitivity, may exceed uncorrected wind speeds by as much as 10 m s-1 in these circumstances. Implications for wind profiling and for describing the backscattering process are discussed. Doppler spectral widths examined for one jet stream passage are found to be narrower in a beam aligned with the horizontal wind at heights near the wind speed maximum than corresponding widths measured in a beam projected at right angles to the jet. The narrowest spectra thus coincide with the most aspect-sensitive echoes, consistent with the hypothesis that such returns result from specular backscattering processes.
The South Atlantic in the Fine-Resolution Antarctic Model
Authors: Stevens D. P. , Thompson S. R.
Published: April 2005

Abstract. The geographical area covered by the Fine-Resolution Antarctic Model (FRAM) includes that part of the South Atlantic south of 24°S. A description of the dynamics and thermodynamics of this region of the model is presented. Both the mean and eddy fields in the model are in good agreement with reality, although the magnitude of the transients is somewhat reduced. The heat flux is northward and in broad agreement with many other estimates. Agulhas eddies are formed by the model and propagate westward into the Atlantic providing a mechanism for fluxing heat from the Indian Ocean. The confluence of the Brazil and Falkland currents produces a strong front and a large amount of mesoscale activity. In the less stratified regions to the south, topographic steering of the Antarctic circumpolar current is important.
Mesoscale variability in the Bransfield Strait region (Antarctica) during Austral summer
Authors: García M. A. , López O. , Sospedra J. , Espino M. , Gràcia V. , Morrison G. , Rojas P. , Figa J. , Puigdefàbregas J. , S.-Arcilla A.
Published: April 2005

Abstract. The Bransfield Strait is one the best-known areas of Antarctica's oceanic surroundings. In spite of this, the study of the mesoscale variability of its local circulation has been addressed only recently. This paper focuses on the mesoscale structure of local physical oceanographic conditions in the Bransfield Strait during the Austral summer as derived from the BIOANTAR 93 cruise and auxiliary remote sensing data. Moreover, data recovered from moored current meters allow identification of transient mesoscale phenomena.
Tidal and residual currents in the Bransfield Strait, Antarctica
Authors: López O. , García M. A. , S.-Arcilla A.
Published: April 2005

Abstract. During the 1992-1993 oceanographic cruise of the Spanish R/V Hespérides, recording equipment was deployed in the Bransfield Strait. Six Aanderaa RCM7 current meters and three Aanderaa WLR7 tide gauges were successfully recovered after an operation period of 2.5 months. Relevant features of the time series obtained are presented and discussed in this paper. The emphasis is placed on the tidal character of the currents and the relative importance of tidal flow in the general hydrodynamics of the strait. For these purposes a dense grid of hydrographic stations, completed during the BIOANTAR 93 cruise, is used. Preliminary geostrophic calculations relative to a 400 m depth, yield current velocities of around 0.20 m s-1 in the study area, whereas the magnitude of tidal currents is seen to be 0.30-0.40 m s-1.
Contrail frequency over Europe from NOAA-satellite images
Authors: Bakan S. , Betancor M. , Gayler V. , Graßl H.
Published: April 2005

Abstract. Contrail cloudiness over Europe and the eastern part of the North Atlantic Ocean was analyzed for the two periods September 1979 - December 1981 and September 1989 - August 1992 by visual inspection of quicklook photographic prints of NOAA/AVHRR infrared images. The averaged contrail cover exhibits maximum values along the transatlantic flight corridor around 50 °N (of almost 2%) and over western Europe resulting in 0.5% contrail cloudiness on average. A strong yearly cycle appears with a maximum (<2%) in spring and summer over the Atlantic and a smaller maximum (<1%) in winter over southwestern Europe. Comparing the two time periods, which are separated by one decade, shows there is a significant decrease in contrail cloudiness over western Europe and a significant increase over the North Atlantic between March and July. Contrail cloud cover during daytime is about twice as high as during nighttime. Contrails are found preferentially in larger fields of 1000 km diameter which usually last for more than a day. Causes, possible errors and consequences are discussed.
Guided waves in the plasma sheet and triggering of a substorm
Authors: Safargaleev V. V. , Lyatsky V. B.
Published: April 2005

Abstract. A guided propagation of magnetoacoustic wave in the plasma sheet located between two lobes of the magnetotail is investigated. The dispersion equation for the wave and equation connecting a disturbance of plasma pressure inside the plasma sheet and amplitude of the plasma sheet boundary oscillations are obtained. For some value of plasma pressure disturbance, the displacement of the plasma sheet boundaries becomes of order of the half-thickness of the plasma sheet. In the case of symmetrical oscillations of the boundaries ("sausage-like" mode), it creates the favourable conditions for reconnection of the magnetic field lines in the magnetotail and may lead to triggering of a substorm. The magnetoacoustic wave may be generated by sudden impulse of the solar wind plasma pressure.
Effective energy loss per electron-ion pair in proton aurora
Authors: Kozelov B. V. , Ivanov V. E.
Published: April 2005

Abstract. Effective energy loss per electron-ion pair produced, (E0), as a function of a particle's initial energy has been obtained for proton transport in the atmosphere. The influence of some transport parameters on the shape of (E0) has been studied. Comparisons with the case of electron transport and with other results were made. It has been shown that: 1. for E0>1 keV, (E0) varies within the range 30-36 eV; 2. as E0 increases the value of (E0) tries to attain an asymptotic value that is the same as for electrons (≈35 eV); 3. (E0) strongly depends on the average energy of secondary electrons, but the energy distribution of secondary electrons is not as important. The range of possible changes in (E0) associated with discrepancies in cross sections has been obtained.
The role of vibrationally excited oxygen and nitrogen in the D and E regions of the ionosphere
Authors: Pavlov A. V.
Published: April 2005

Abstract. In this paper we present the results of a study of the effect of vibrationally excited oxygen, O*2, and nitrogen, N*2, on the electron density, Ne, and the electron temperature, Te, in the D and E regions. The sources of O*2 are O-atom recombination, the photodissociation of O3, and the reaction of O3 with O at D region altitudes. The first calculations of O*2( j) number densities, Nj, are obtained by solving continuity equations for the models of harmonic and anharmonic oscillator energy levels, j=1-22. It is found that day time values of Nj are less than nighttime values. We also show that the photoionization of O*2 ( j ≥ 11) by Lα-radiation has no influence on the D region Ne. In the nighttime D region the photoionization O*2 ( j ≥ 11) by scattered Lα-radiation can be a new source of O+2. We show that the N*2 and O*2 de-excitation effect on the electron temperature is small in the E region of the ionosphere and cannot explain experimentally observed higher electron temperatures.
Non-Gaussian probability distributions of solar wind fluctuations
Authors: Marsch E. , Tu C. Y.
Published: April 2005

Abstract. The probability distributions of field differences ∆x(τ)=x(t+τ)-x(t), where the variable x(t) may denote any solar wind scalar field or vector field component at time t, have been calculated from time series of Helios data obtained in 1976 at heliocentric distances near 0.3 AU. It is found that for comparatively long time lag τ, ranging from a few hours to 1 day, the differences are normally distributed according to a Gaussian. For shorter time lags, of less than ten minutes, significant changes in shape are observed. The distributions are often spikier and narrower than the equivalent Gaussian distribution with the same standard deviation, and they are enhanced for large, reduced for intermediate and enhanced for very small values of ∆x. This result is in accordance with fluid observations and numerical simulations. Hence statistical properties are dominated at small scale τ by large fluctuation amplitudes that are sparsely distributed, which is direct evidence for spatial intermittency of the fluctuations. This is in agreement with results from earlier analyses of the structure functions of ∆x. The non-Gaussian features are differently developed for the various types of fluctuations. The relevance of these observations to the interpretation and understanding of the nature of solar wind magnetohydrodynamic (MHD) turbulence is pointed out, and contact is made with existing theoretical concepts of intermittency in fluid turbulence.
Nonlinear shock structure in a weakly ionised magnetoplasma
Authors: Dwivedi C. B. , Tripathy S. C.
Published: April 2005

Abstract. The formation of a neutral induced weak nonlinear shock structure in a weakly ionised magnetoplasma has been analytically investigated. Using the reductive perturbation method, basic dynamical equations of a three-component (electron, ion and neutral) plasma have been reduced to a well-known Burger equation which can support a weak shock solution. Its stationary and initial value solutions have been derived to describe the characteristics of the weak shock profile. Asymptotic behaviour of the Burger solution results in a saw-tooth structure which has a practical implication to predict the nonlinear steepened structure of the nighttime irregularity in the lower portion of the Earth's ionosphere. Accordingly, it is suggested that the observation of saw-tooth shape of nighttime irregularity at 92 km could be attributed to the nonlinear saturation of the NILF mode instability as proposed by Dwivedi and Das in 1992. However, exact experimental verification of this suggestion requires more data on nighttime irregularity in the mesosphere and lower thermosphere (80-95 km) for a wide range of scale sizes extending up to about 1 km and above.
Influence of ion attachment on the vertical distribution of the electric field and charge density below a thunderstorm
Authors: Qie X. , Soula S. , Chauzy S.
Published: April 2005

Abstract. A numerical model called PICASSO [Production d'Ions Corona Au Sol Sous Orage (French) and Production of Corona Ions at the Ground Beneath Thundercloud (English)], previously designed, is used to describe the evolution of the principal electrical parameters below a thunderstorm, taking into account the major part played by corona ions. In order to improve the model restitution of a real situation, various improvements are performed: an initial vertical distribution of aerosol particles is introduced instead of the previously used uniform concentration; time and space calculation steps are adjusted according to the electric field variation rate; the upper boundary condition is improved; and the coefficients of ion attachment are reconsidered with an exhaustive bibliographic study. The influence of the ion attachment on aerosol particles, on the electric field and charge density aloft, is studied by using three different initial aerosol particle concentrations at ground level and two types of initial vertical distributions: uniform and non-uniform. The comparison between field data and model results leads to adjust the initial aerosol particle concentration over the experimental site at the value of 5000 cm-3 which appears to be highly realistic. The evolutions of the electric field and of the charge density at altitude are greatly influenced by the aerosol concentration. On the contrary, the surface intrinsic field, defined as the electric field that would exist underneath a thundercloud if there were no local charges, is weakly affected when the model is forced by the surface field. A good correlation appears between the success in the triggered lightning attempts and this intrinsic field evaluation. Therefore, when only the surface field is available, the model can be used in a triggered lightning experiment.
The geometrical and fractal properties of visible radiances associated with breaking waves in the ocean
Authors: Raizer V. Y. , Novikov V. M. , Bocharova T. Y.
Published: April 2005

Abstract. We consider the natural processes of wind-wave-breaking in the ocean in terms of fractal dimension. Digital algorithms for the analysis of aircraft optical images are employed to investigate spatial and statistical characteristics of foam streaks and whitecaps. The new results are as follows: 1. the fractal dimension of the wave-breaking set (foam streaks and whitecaps) depends on the ocean surface state and changes from dH=1.05 to 1.25; 2. the fractal dimension differs from foam streaks and whitecaps - ds=1.23 and 1.39, respectively.
Dominance in mitochondrial disorders
Authors: Zeviani M. , Carelli V.
Published: April 2005

Dominant traits are rare in mitochondrial disorders but include important nosological entities such as alterations of organellar biogenesis and abnormalities in the structural integrity of the mitochondrial genome, determined by mutations in genes involved in its maintenance and propagation. Both haplo‐insufficiency and ‘gain‐of‐function’ mechanisms underlie the pathogenesis of these disorders. Impairment in energy supply, abnormal mitochondrial trafficking, increased toxic damage by oxygen radicals, and mitochondrially driven apoptosis have been documented in different dominant syndromes. In addition, maternally inherited mutations of mitochondrial DNA can sometimes simulate dominant traits, mainly because of reduced penetrance and complex interaction with genetic and environmental factors.
Congenital brain malformations in mitochondrial disease
Authors: Brown G. K.
Published: April 2005

The majority of patients with mitochondrial disease have some degree of neuropathology and this is usually degenerative in nature. However, in a subset of mitochondrial diseases there are additional specific and characteristic congenital malformations in the brain. These developmental abnormalities are not unique to mitochondrial diseases and their association with only some conditions suggests that they are not simply due to energy deprivation or accumulation of metabolites such as lactic acid. Pathogenic mechanisms are at present unknown, but interference with neurotransmitter homeostasis, in addition to altered energy metabolism, may be important. The postnatal evolution of the neuropathology in these conditions and the type and pattern of the malformations suggest secondary degeneration of specific brain structures during fetal life rather than primary interference with developmental pathways.
Dispersion-Weighted Kappa: An Integrative Framework for Metric and Nominal Scale Agreement Coefficients
Authors: Schuster Christof , Smith David A.
Published: April 2005

The rater agreement literature is complicated by the fact that it must accommodate at east two different properties of rating data: the number of raters (two versus more than two) and the rating scale level (nominal versus metric). While kappa statistics are most widely used for nominal scales, intraclass correlation coefficients have been preferred for metric scales. In this paper, we suggest a dispersion-weighted kappa framework for multiple raters that integrates some important agreement statistics by using familiar dispersion indices as weights for expressing disagreement. These weights are applied to ratings identifying cells in the traditional inter-judge contingency table. Novel agreement statistics can be obtained by applying less familiar indices of dispersion in the same way.
Sheffield, Lyceum Theatre: Nigel Osborne's ‘The Piano Tuner’
Authors: Conway Paul
Published: April 2005

The difficulties of attempting to translate a popular novel into an operatic medium were apparent in Nicholas Maw's recent opera based on Sophie's Choice. Nigel Osborne's new opera followed the same dangerous path in tackling Daniel Mason's highly successful historical novel, The Piano Tuner.
London, South Bank Centre: Bryars's ‘From Egil's Saga’
Authors: Stein Robert
Published: April 2005

Once again Gavin Bryars confounds many of our expectations with his laid-back take on the world's dramas. The War in Heaven (1992) featured a serene counter-tenor and is anything but bellicose. In The Sinking of the Titanic (1969), performed as a companion-piece in this concert, Bryars's band appropriately plays on undisturbed by the ship sundering all around it. The central drama of Dr Ox's Experiment (1997) is one of celebrating stasis. And so it is that Bryars's latest work From Egil's Saga (2004), a setting of battle-hardened texts by the 13th-century Icelandic poet and warrior Snorri Sturuson, has that calm, quiet, lamenting detachment – ‘a portrait of Egil at the end of his days’, as the composer has characterized it. Once again the world is seen through a piece of interestingly darkened glass.
Klemperer the Composer
Authors: Walton Chris , Johnson Bret
Published: April 2005

KLEMPERER: Symphony No. 1 (Symphony in Two Movements); Symphony No. 2; Marcia funèbre; Scherzo; Recollections; Merry Waltz. Staatsphilharmonie Rheinland-Pfalz c. Alun Francis. CPO 999 987-2.
Reports from London and Bristol
Authors: Anderson Martin
Published: April 2005

Deptford and South Bank Centre: Two Scottish Piano Concertos

Bristol: John Pickard's Violin Sonata

Wigmore Hall: Nordheim's ‘Five Stages for Four’
Possible fault plane in a seismic gap area of the southern Apennines (Italy) revealed by receiver function analysis
Authors: Lucente Francesco Pio , Piana Agostinetti Nicola , Moro Marco , Selvaggi Giulio , Di Bona Massimo
Published: April 2005

Unusual features in teleseismic receiver function, computed at a single three‐component seismic station, reveal the presence of a dipping interface in the shallow crust with a pronounced seismic velocity contrast in the Campania‐Lucania region, southern Apennines (Italy). The locus of this finding is the Pergola‐Melandro basin, situated between the maximum intensity areas of two of the most destructive earthquakes reported in the Italian seismic catalogue: theM∼ 7.0 Val d'Agri earthquake (1857) and theMs= 6.9 Irpinia earthquake (1980). This area is not associated with known historical events and for this reason is currently object of investigation as a potential seismic gap, where the probability of future ruptures is higher than in surrounding regions, also for the static stress increase caused by the two above mentioned earthquakes. Through an inversion procedure applied to the computed receiver functions, we are able to satisfactorily constrain the strike, dip, depth, and velocity contrast of this crustal discontinuity, whose geometric characteristics closely match those proposed by some authors for the sources of the two neighboring earthquakes. We argue that the detected interface is the seismogenic source which fills the gap. The findings of this study could open new perspectives both in the study of seismic gap areas and in the identification of historical earthquake sources, offering a new and effective tool to locate, investigate, and constrain buried or unknown faults.