bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method for the identification and characterization of clusters of schools along the transect lines of fisheries-acoustic surveys
Authors: Petitgas Pierre 
Published: July 2003

AbstractThe school-aggregation pattern (schools and clusters of schools) is presumed to play a significant role in determining pelagic fish-stock catchability. However, its analysis has seldom been undertaken because it requires field-behavioural data that is seldom available. Such information can now be obtained by analysing school-based data of fisheries-acoustic surveys. This paper proposes a method for doing so. The method allows for the identification of clusters of schools and the estimation of their parameters along one-dimensional, acoustic-survey transect lines. It is based on a spatial point-process approach that considers schools as point events occurring along the track sailed by a ship. More precisely, it is based on defining a maximum distance between schools in a cluster. This distance is chosen to optimize various criteria and in particular that of homogeneity concerning school location inside the clusters and school number per km. The algorithm is described and applied to a series of acoustic surveys carried out in the Bay of Biscay. The pertinence of the clusters obtained by the algorithm is evaluated by analysing which component of the spatial distribution of the schools corresponds to those clusters. This involves considering all the distances between school events and performing simulations of cluster point processes. The school clusters obtained by the proposed algorithm represent a small-range structure of a few kilometres when a longer-range structure of tens of kilometres was also present in the data.
Burrow density and stock size fluctuations of Nephrops norvegicus in a semi-enclosed bay
Authors: Smith C.J , Papadopoulou K.-N 
Published: July 2003

Abstract
An underwater television technique was used to investigate burrow density of Nephrops norvegicus in a large semi-enclosed bay in the west central Aegean. Pagasitikos Bay has the shallowest occurrence of Nephrops in high densities in Greek waters with an estimated population area of 376 km2. As trawling is by law prohibited in the bay, Nephrops is fished only by bottom nets. Burrow densities were estimated seasonally (May, August and November 1998 and February 1999) by video sled transects at nine stations around the bay. Bottom trawls were undertaken to estimate animal abundance, mean individual carapace length and mean weight. Total stock estimate (number and weight) was undertaken for 100 and 75% burrow occupancy with the ground delimited by the 60 m contour. Annual removal by fishermen was estimated to be 1.5–2% of the stock. Densities were found to be higher than in other Greek Nephrops grounds. Variations in burrow density were found both between stations and within stations over time, with an overall decrease in density in 1999. The decrease in density during 1999, in conjunction with an increase in mean carapace length from the trawl catches was attributed to an eutrophication event evidenced by a flock layer settling onto the seabed and causing, in the worst cases, patches of anoxic surface sediments. The event was most probably the result of high nutrient run-off into the bay.
The diel-vertical distribution and characteristics of pre-spawning aggregations of pollock (Pollachius virens) as inferred from hydroacoustic observations: the implications for survey design
Authors: Neilson John D , Clark Donald , Melvin Gary D , Perley Peter , Stevens Chris 
Published: July 2003

Abstract
The characteristics of pollock (the synonymous European common name is saithe) pre-spawning aggregations were described at two locations with contrasting bathymetric features on the Scotian Shelf, off the Canadian Maritimes. The data were collected using a split-beam echosounder onboard a research vessel, augmented with periodic, bottom-trawl samples. Pollock form aggregations each fall that persist at the same location over time. Such aggregations appeared to be associated with spawning. Hydroacoustic information indicates that pollock become more densely aggregated at night. This could reflect movement away from the study area during the day, or changes in the proportion of pollock in the acoustic dead zone over the 24-h period. The hydroacoustic information indicates that while pollock can occur up to 30 m off bottom, the greatest proportion remains within 1–5 m off bottom during both day and night. The length composition of the pollock aggregations differed between the two sites, with larger fish found at the site further offshore. Within an aggregation, there was spatial heterogeneity with respect to fish size, with larger fish found primarily within the core area of aggregation as shown by the hydroacoustics. An appropriate survey design for obtaining an index of abundance for pollock would reflect both the contagious (patchy) distribution as they prepare to spawn, and the diel differences in the availability of the fish to the hydroacoustic-sampling gear.
Modelling stochastic fish stock dynamics using Markov Chain Monte Carlo
Authors: Lewy P. , Nielsen A. 
Published: July 2003

Abstract
A new age-structured stock dynamics approach including stochastic survival and recruitment processes is developed and implemented. The model is able to analyse detailed sources of information used in standard age-based fish stock assessment such as catch-at-age and effort data from commercial fleets and research surveys. The stock numbers are treated as unobserved variables subject to process errors while the catches are observed variables subject to both sampling and process errors. Results obtained for North Sea plaice using Markov Chain Monte Carlo methods indicate that the process error by far accounts for most of the variation compared to sampling error. Comparison with results from a simpler separable model indicates that the new model provides more precise estimates with fewer parameters.
Demersal assemblages and depth distribution of elasmobranchs from the continental shelf and slope off the Balearic Islands (western Mediterranean)
Authors: Massutí Enric , Moranta Joan 
Published: July 2003

Abstract
The analysis of 131 hauls from four bottom trawl fishing surveys carried out between depths of 46 and 1713 m in two different areas off the Balearic Islands yielded a total of 23 elasmobranch species belonging to eight families. Cluster analysis and multidimensional scaling (MDS) ordination were applied to detect zonation patterns and some ecological parameters (e.g. species richness, abundance and biomass, mean weight, diversity and evenness) were calculated for each assemblage. For each area, analysis of similitude (ANOSIM) and similarity percentage analysis (SIMPER) were also applied to detect differences between seasons and depths. For the most important species (Galeus melastomus, Scyliorhinus canicula, Centroscymnus coelolepis, Etmopterus spinax, Squalus blainvillei, Raja naevus, Raja asterias, Raja clavata, Raja miraletus and Raja oxyrhinchus), abundance and size distributions were analysed by depth.
Spatial dynamics of a nearshore, micronekton sound-scattering layer
Authors: Benoit-Bird Kelly J , Au Whitlow W.L 
Published: July 2003

AbstractIn the Hawaiian Islands, there is a distinct resident community of micronekton, distributed along a narrow band where the upper underwater slopes of the islands meet the oceanic, mesopelagic environment. This mesopelagic boundary community serves as an important food resource to many animals. The goal of this work was to examine spatial heterogeneity of the Hawaiian mesopelagic boundary biomass at a range of scales, in the context of its diel vertical and horizontal migrations. A modified echosounder was used to sample the coasts of three Hawaiian Islands, permitting a range of scales from several meters to several kilometers to be assessed rapidly. The Hawaiian mesopelagic boundary community fits the hierarchical model of patch structure with patches within patches that are part of a larger-scale matrix of patches. Large differences in the overall distribution patterns of the mesopelagic boundary community exist along with a wide range of overall mesopelagic-animal densities. High animal-density locations have boundary-community layers with a large (kilometers) horizontal extent, and low animal-density locations have small (tens of meters), discrete patches. Higher animal-density locations are also more complex than low-density sites, with more levels of patchiness within the same range of spatial scales. Both time of day and distance from shore significantly affected the geometric and density characteristics as well as the distribution of aggregations within the boundary layer. Horizontal and vertical structures of the mesopelagic boundary community are also coupled. In high-density sites, there is strong vertical layering in acoustic-scattering strength while in low-density sites vertical acoustic structure is absent. The differences observed in the distribution of the mesopelagic boundary community at different levels of overall mesopelagic-animal density suggest biological forcing as the dominant mechanism. A description of heterogeneity in the mesopelagic boundary community in Hawaii is the first step in understanding its importance to both neritic and oceanic ecosystems and its potential for linking these two systems.
Multiple myeloma biology: lessons from the 5TMM models
Authors: Vanderkerken Karin , Asosingh Kewal , Croucher Peter , Van Camp Ben 
Published: July 2003

Summary:  Multiple myeloma (MM) is a B cell neoplasm characterized by the monoclonal proliferation of plasma cells in the bone marrow, the development of osteolytic lesions and the induction of angiogenesis. These different processes require three‐dimensional interactions, with both humoral and cellular contacts. The 5TMM models are suitable models to study these interactions. These murine models originate from spontaneously developed myeloma in elderly mice, which are propagated by in vivo transfer of the myeloma cells into young syngeneic mice.In this review we report on studies performed in the 5TMM models with special emphasis on the homing of the myeloma cells, the characterization of the migrating and proliferating clone and the identification of the isotype switch variants. The bone marrow microenvironment was further targeted with osteoprotegerin (OPG) to block the RANK/RANKL/OPG system and with potent bisphosphonates. Both treatments resulted in a significant protection against myeloma‐associated bone disease, and they decreased myeloma disease, as evidenced by a lower tumor load and an increased survival of the mice. These different studies demonstrate the strength of these models, not only in unraveling basic biological processes but also in the testing of potentially new therapeutic targets.
Inflammatory bowel disease after liver transplantation: the effect of different immunosuppressive regimens
Authors: Haagsma E. B. , Van Den Berg A. P. , Kleibeuker J. H. , Slooff M. J. H. , Dijkstra G. 
Published: July 2003

SummaryBackground : Seemingly conflicting results have been reported on the prevalence and severity of inflammatory bowel disease after liver transplantation. Regimens with different combinations of drugs can be used for immunosuppression after transplantation.Aim : To study retrospectively the prevalence of inflammatory bowel disease after liver transplantation, and the possible relationship with maintenance immunosuppressive regimens.Methods : All 78 patients with end‐stage primary sclerosing cholangitis (48 patients) or autoimmune cirrhosis (30 patients), transplanted between 1979 and July 2001, and with a follow‐up of at least 1 year, were eligible for this study. In addition to patient and transplant characteristics, data on inflammatory bowel disease and immunosuppression before and after transplantation were collected. The Kaplan–Meier method was used for survival analysis. Possible risk factors for inflammatory bowel disease after transplantation were analysed by Cox univariate and multivariate regression.Results : The median follow‐up after transplantation was 7.2 years (range, 1.1–22.3 years). Nine of 25 patients with pre‐transplant inflammatory bowel disease experienced flare‐ups after transplantation. Six of 53 patients without pre‐transplant inflammatory bowel disease developed de novo inflammatory bowel disease after transplantation. The cumulative risks (standard errors in parentheses) for inflammatory bowel disease were 6% (3%), 12% (4%) and 20% (5%) at 1, 3 and 5 years after transplantation, respectively. The inflammatory bowel disease‐free survival was significantly higher in patients not receiving tacrolimus vs. those receiving tacrolimus, in patients receiving azathioprine vs. those not receiving azathioprine and in patients taking the regimen prednisolone–azathioprine–ciclosporin A vs. those taking tacrolimus–prednisolone. Pre‐transplant inflammatory bowel disease and the use of tacrolimus were found to be independent predictors for inflammatory bowel disease after transplantation.Conclusions : The prevalence of inflammatory bowel disease after liver transplantation is affected by the immunosuppression used. Azathioprine seems to have a protective effect and tacrolimus a promoting effect.
The effect of metoclopramide on QT dynamicity: double‐blind, placebo‐controlled, cross‐over study in healthy male volunteers
Authors: Elli̇dokuz E. , Kaya D. 
Published: July 2003

SummaryBackground : Metoclopramide, a central and peripheral dopamine type 2 receptor antagonist, has been used as an attractive and safer alternative to cisapride. However, cardiac side‐effects have also been reported with this drug.Aim : To evaluate the effects of intravenous metoclopramide administration on cardiac repolarization using QT dynamicity, a reliable indicator of arrhythmic side‐effects.Methods : The effect of metoclopramide on cardiac repolarization was evaluated in 10 healthy male volunteers in the supine position. Metoclopramide (10 mg) or placebo was administered intravenously at random in a double‐blind, cross‐over manner to the participants during continuous electrocardiographic recording in the supine position. The 30‐min stationary segments of the recordings before and after drug administration were used to investigate QT dynamicity.Results : Metoclopramide administration, but not placebo, resulted in steeper QT/RR slopes compared with the pre‐drug values (metoclopramide: 0.037 ± 0.004 vs. 0.064 ± 0.012; P = 0.041; placebo: 0.045 ± 0.006 vs. 0.050 ± 0.004; P = 0.563). In a two‐way analysis of variance model, metoclopramide administration also increased the QT variance independently (F = 6.225, P = 0.023).Conclusions : Metoclopramide administration increases the QT/RR slope and QT variance. These findings may partly explain the underlying mechanism of ventricular arrhythmias associated with metoclopramide.
Tachykinins and their possible modulatory role on testicular function: a review
Authors: Debeljuk Luciano , Rao Jaladanki N. , Bartke Andrzej 
Published: July 2003

SummaryTachykinins are vasoactive and smooth muscle‐contracting peptides with widespread localizations. Tachykinins have been localized in the nerve fibres that supply the testes, in the Leydig cells of different animal species, and also in Sertoli cells of the Siberian hamster testes. The presence of substance P (SP) has also been demonstrated in ejaculated human spermatozoa and in the seminal plasma. Tachykinins have been shown to inhibit the release of testosterone by testicular fragments or by isolated Leydig cells in vitro. Acting on Sertoli cells, tachykinins have been shown to stimulate the release of lactate and transferrin by these cells in vitro, and also to stimulate aromatase activity.Leydig and Sertoli cells express the Preprotachykinin A gene, and this fact strongly suggests that tachykinins can be synthesized in the testes. These findings suggest that tachykinins may have a physiological function in the testes as modulators of the functions of the different cell types contained in these organs.
Analysis of factors associated with multinucleate formation in human IVF
Authors: Shibahara Hiroaki , Yamanaka Hiroko , Hirano Yuki , Kikuchi Kumiko , Yamanaka Seiji , Suzuki Tatsuya , Takamizawa Satoru , Suzuki Mitsuaki 
Published: July 2003

SummaryThis study was carried out to analyse if some of the sperm parameters assessed by computer‐aided sperm analysis (CASA) are associated with multinucleate formation in human in vitro fertilization (IVF). In the present study, 137 IVF‐embryo transfer (ET) treatment cycles in which pronucleate formation could be observed were enrolled. Sperm parameters after swim‐up were assessed using CASA and strict criteria. Thirty‐two (2.3%) of 1368 oocytes fertilized were judged as multinucleate formation, which occurred in 25 of 137 IVF‐ET treatment cycles, giving the incidence of 18.2%. The factors associated with multinucleate formation were analysed. There were significant differences of the numbers of oocytes collected (13.9 vs. 9.2; p = 0.028), fertilization rate (88.8% vs. 71.9%; p = 0.011), curvilinear velocity (VCL) (162.7 μm/sec vs. 149.1 μm/sec; p = 0.034), average path velocity (VAP) (100.3 μm/sec vs. 93.1 μm/sec; p = 0.016), and amplitude of lateral head displacement (ALH) (5.9 μm vs. 5.3 μm; p = 0.046) between 25 cycles with multipronucleate formation and 112 cycles with two pronucleate formations. However, there were no significant differences of women's age or the number of sperm inseminated between the two groups. These findings suggest that prediction of multinucleate formation in human IVF might be possible in patients when the number of oocytes collected is higher and sperm motility parameters after swim‐up are faster. However, prevention of multinucleate formation seems to be unnecessary because a higher successful IVF‐ET outcome is expected as a result of the excellent fertilization rate in these patients.
Isolation and characterization of a human sperm antigen gene h‐Sp‐1
Authors: Kanazawa Ri‐Ichiro , Komori Shinji , Sakata Kazuko , Tanaka Hiroyuki , Sawai Hideaki , Tsuji Yoshiyuki , Koyama Koji 
Published: July 2003

SummaryWe isolated and characterized a human sperm antigen gene (h‐Sp‐1) from human testis complementary DNA using antiserum against the human sperm membrane. Northern blot analysis detected two transcripts (2.3 and 1.1 kb) of the h‐Sp‐1 gene. The 2.3‐kb transcript is ubiquitous, whereas the 1.1‐kb transcript is specific to the human testis with a high level of expression. Determination of the base sequence of h‐Sp‐1 showed a size of 2170 bp and 43.4% homology with human synaptophysin. The base sequence indicates a molecule consisting of 259 amino acids, with four hydrophilic and four hydrophobic regions. In order to further characterize the h‐Sp‐1 molecule, we synthesized the probable region of amino acids with high antigenicity based on the amino acid sequence (amino acid nos. 174–198) and immunized rabbits to prepare an antiserum. In our experimental model of fertilization between human sperm and zona pellucida‐free hamster ova, partial inhibition of fertilization was observed. We were able to synthesize a large quantity of recombinant protein by inserting the h‐Sp‐1 gene into a baculovirus vector and infecting spodoptera frugiperda culture cells (sf9 insect cells). The synthesized protein had a molecular weight of 30 kDa. We then immunized Balb/c mice with this protein to prepare a monoclonal antibody (G3G9), which was used to localize the h‐Sp‐1 molecule in sperm and tissues (e.g. testis). The h‐Sp‐1 molecule was present in the cell membrane from the head to tail of human sperm. Staining of the testis and epididymis also showed h‐Sp‐1 to be present in spermatogonia, spermatocyte, sperm and epididymal duct epithelium. These findings suggest that the h‐Sp‐1 molecule is expressed in sperm and testes and plays a role in fertilization.
Meiotic segregation of sex chromosomes in mosaic and non‐mosaic XYY males: case reports and review of the literature
Authors: Rives N. , Siméon N. , Milazzo J. P. , Barthélémy C. , Macé B. 
Published: July 2003

SummaryThe aim of this study was to determine the incidence of sex chromosome aneuploidy in spermatozoa of two males with a 47,XYY karyotype and one male with a 46,XY/47,XYY constitution. Spermatozoa obtained from two oligospermic patients and one volunteer semen donor were studied by multicolour fluorescence in situ hybridization. In the XY/XYY male, the frequencies of X‐bearing to Y‐bearing sperm were significantly different from the 1 : 1 expected ratio. Significantly increased frequencies were found in the mosaic and non‐mosaic males for 24,XX and 24,YY sperm when compared with control donors. The number of 24,XY sperm was significantly different from the controls in the XYY males, but not in the mosaic male. The incidence of disomy 18 and the rate of diploidy also increased in the three patients. However, the mosaic male had the lowest cumulative rate of disomic and diploid spermatozoa when compared with the two XYY patients. Our data suggest that: (i) chromosome abnormalities observed in spermatozoa of the two XYY oligoasthenoteratospermic (OAT) males arise through segregation errors in XY germ cells rather than normal meiosis of XYY germ cells, (ii) mosaic XYY males with normal semen parameters have a lower risk of producing offspring with a sex chromosomal abnormality than OAT males with XYY karyotype.
Cavernosal tissue nitrite, nitrate, malondialdehyde and glutathione levels in diabetic and non‐diabetic erectile dysfunction
Authors: Tuncayengin Alper , Biri Hasan , Onaran Metin , Şen İlker , Tuncayengin Özlem , Polat Fevzi , Erbaş Deniz , Bozkirli İbrahim 
Published: July 2003

SummaryThe aim of this study is to investigate the role of nitric oxide (NO) stabile end products, membrane lipid peroxidation and antioxidant defensive mechanism in diabetic erectile dysfunction (ED) and compare these parameters with non‐diabetic ED groups. We examined the penile cavernosal tissues, obtained from 22 patients who had undergone surgery of penile prostheses implantation, for the nitrite, nitrate, malondialdehyde (MDA) and glutathione (GSH) levels. Eight patients were suffering from diabetic erectile dysfunction (ED) and 14 patients had non‐diabetic ED. Nitrite and nitrate levels were lower; MDA and GSH levels were higher in the diabetic group. There were statistically significant differences between diabetic and non‐diabetic groups amongst the nitrite (p < 0.001), nitrate (p < 0.01), MDA (p < 0.001) and GSH (p < 0.01) levels. Our data provide evidence that NO deficiency, possibly due to the membrane lipid peroxidation and defective antioxidant defensive mechanism, may contribute to the development of diabetic ED and thus is involved in the pathogenesis of ED in diabetic patients.