bluuebunny/crossref_metadata_2025 huggingface dataset:
Runoff and sheet erosion from tillage trials under artificial rainfall at Harden, New South Wales
Authors: Kinnell PIA
Published: April 2005

Artificial rainfall was applied to g-m-long plots after the harvest of a canola crop in experiments on a grazed cropping system using a rotation that alternated wheat with lupins and canola. Three tillage treatments were selected for the experiments: one was a direct-drill treatment, while the other two involved the use of a reduced tillage practice during the preparation of the seed bed. Tillage treatment was found to have no substantial effect on runoff and sediment concentration resulting from sheet erosion during the post-harvest period. At sowing time, tillage again had no significant effect on sediment concentration but did have a significant effect on runoff. The roughness produced by the tillage provided a substantial capacity to store water and detached soil particles in surface depressions immediately after cultivation, and the decline in this surface roughness during rainfall was sufficiently small to cause little or no runoff when 1h of 70 mm/h rain was applied to a cultivated surface. The results support indications from SOILOSS, a model that provides local implementation of the Revised Universal Soil Loss Equation (RUSLE), that reduced-till may be as effective as direct-drill at conserving soil at this site. However, since the experiments were restricted to sheet erosion, and no experiments were performed between sowing and harvest or with other crops in the rotation, the results do not provide unconditional support for the SOILOSS result. Despite the result of the experiments reported here, soil erosion risk is likely to be substantially reduced on a field scale through the use of tillage practices which, like the direct-drill treatment, maintain anchored and unanchored crop residue during the fellow and post-sowing periods. Data were also collected in relation to an examination of the ability of the Soil Water Infiltration and Movement (SWIM) model to predict runoff during the post-harvest period. SWIM tended to underpredict runoff but the difference between the observed amount of runoff and that predicted by SWIM was statistically not significant.
Differences in mineral ratios between disaggregated and original clay fractions in some South African soils as affected by amendments
Authors: Buhmann C , Rapp I , Laker MC
Published: April 2005

Conflicting information is available on the propensity different soil clays exhibit to dispersion. We therefore assessed the relative stability of the clay components of 12 soil samples, from various parts of South Africa, to predominantly physical disruption by a mild disruptive treatment [mechanical shaking for 5 min in distilled water (DW), and after the addition of phosphogypsum (PG; 2% by weight) and polyacrylamide (PAM; 0.04% by weight)]. The soils differed markedly in their physical and chemical properties. Clay fractions were of mixed mineralogy and dominated by kaolinite, illite, or smectite. Comparison of the clay mineral composition of the disaggregated clay with that of the original <2 �m fraction indicated that the disaggregated clay composition depended on the amendment. In DW, clay-sized quartz and feldspar were disaggregated preferentially over layer silicates. Within the phyllosilicate fraction, the 2:1 clay minerals (mica, smectite) were on average slightly more easily disaggregated than kaolinite. Goethite was the least easily detached clay component in DW. The increase in quartz and feldspar proportions relative to the other components of the clay fraction was dramatically more pronounced when the soils were mixed with PG. With PAM, however, differences in the nature of the clay fraction between original and disaggregated clay were only marginal. Disruption was not particle-size related, as the minerals of the fine-clay fraction showed no selective increase in any of the treatments. These findings indicate that the most inert members of the clay fraction are most actively involved in the process of disaggregation. PG influenced disaggregation in a manner markedly different from that of PAM. Gypsum preferentially stabilised components with a net negative charge over uncharged species. PAM, in contrast, seemed to affect all clay components equally, independent of charge characteristics.
Changes in soil solution composition and aluminium speciation under legume based pastures in response to long term phosphate fertiliser applications
Authors: Manoharan V , Loganathan P , Parfitt RL , Tillman RW
Published: April 2005

This study describes some of the effects of 8 years of annual application of 6 types of phosphatic fertilisers on the chemical composition and aluminium (Al) speciation in soil solution extracted from a soil under pasture. Soil samples at 2 depths, 0-30 and 30-75 mm, were collected at the end of 8 years. Soil solutions were extracted by centrifuging at 12 000 RCF and analysed for Al, Na, K, Ca, Mg, F, NO3, Cl, and SO4, as well as pH and ionic strength. Soil and soil solution pH were significantly increased at both depths by application of North Carolina phosphate rock (NCPR) compared with the control. In contrast, diammonium phosphate (DAP) significantly decreased the soil and solution pH. Single superphosphate (SSP) did not have any significant effect on soil or solution pH compared with the untreated control. The surface soil (0-30 mm) solution pH was on average 0.6 of a unit higher than the subsurface soil (30-75 mm) solution pH. Total monomeric Al concentration [Al], measured by the pyrocatecol violet (PCV; 4 min) method, ranged from 1.5 to 4.8 �M in the surface soil and 2.5 to 12.2 �M in the subsurface soil. The DAP and higher rates of SSP application resulted in a large increase in total and inorganic monomeric [Al] in the soil solution extracted from the subsurface soil. Total soluble [F] ranged from 2.7 to 23.5 �M and 3.2 to 25.6 �M in the surface and subsurface soils, respectively, and was significantly increased by the application of NCPR and by higher rates of SSP. The predominant forms of inorganic monomeric Al present in the soil solution were estimated to be the non-phytotoxic Al-F complexes, AlF2+, and AlF2+. There was a marked decrease in toxic Al species (Al3+, Al(OH)2+, Al(OH)2+) in soil solution following NCPR and SSP application. This was due primarily to complexation of Al with F derived from these fertilisers forming non-toxic AI-F complexes. The results suggest that the long-term application of reactive phosphate rock such as NCPR may contribute to amelioration of soil acidity and Al toxicity under legume-based pastures. In contrast ammonium-containing phosphate fertilisers such as DAP probably decrease soil pH and increase the formation of toxic Al species in the soil solution.
Comparing modelled and observed effects of ash additions on chemistry of a highly acid soil
Authors: Khanna PK , Ludwig B , Raison RJ
Published: April 2005

The chemical composition of soil solutions (field percolates collected in situ and laboratory saturation extracts) and the amount of salt-extractable cations were measured at several microsites (unburnt, moderately burnt, and intensely burnt ashbeds) after a fuel reduction burning in a subalpine Eucalyptus pauciflora forest. Soil samples were collected 1, 58, 375, 745, and 1095 days after the fire, and soil percolates were obtained on 17 occasions during the initial year. A model of coupled equilibria, which includes insoluble salts, multiple cation exchange, and inorganic complexation, was used to describe soil chemical changes after fire and ash addition. The model was able to describe temporal changes in cation concentrations of held percolates and soil exchangeable cations. Measurements of extractable cations using unbuffered salt solution on samples taken immediately after fire suggest immediate changes in exchangeable cations which were related to solubilisation of cations from ash, and not to changes in exchangeable cations in soils. Modelling suggests that under natural conditions the differences in solubility of cations in ash result in slow changes in exchangeable cations extending over a period of 6 years or more. The time required to reacidify the surface layer of ashbed soil was estimated to be 45 years when annual acid input was 0.5 kmol H+/ha.
Uptake of phosphorus from different sources by Lotus pedunculatus and three genotypes of Trifolium repens .2. Forms of phosphate utilised and acidification of the rhizosphere
Authors: Trolove SN , Hedley MJ , Caradus JR , Mackay AD
Published: April 2005

Improvements in the ability of legumes to utilise applied phosphate (P) could lower fertiliser requirements. Earlier studies have found differences between legume species and genotypes of Trifolium repens in their ability to take up P from P sources that vary in solubility. Acidification of the rhizosphere may account for different P utilisation, especially from reactive phosphate rocks. To investigate differences in the ability of legumes to acidify their rhizosphere and extract various forms of P, Lotus pedunculatus and 3 genotypes of white clover that varied in their ability to respond to added P were grown in root study containers with either unfertilised soil, or soil fertilised with either monocalcium phosphate (MCP) or North Carolina phosphate rock (NCPR). After 6 weeks of plant growth, the containers were dismantled and 10 thin soil slices were taken 0-8 mm from the rhizoplane. These slices were fractionated for various P forms and pH was measured. All 4 legumes, especially lotus, acidified their rhizosphere. This resulted in negligible depletion of the small, H2SO4-P-i fraction (Pi, inorganic phosphorus) of unfertilised and MCP-fertilised soil, but caused direct dissolution of NCPR. The predominant forms of P depleted in the MCP-fertilised soil were the resin-Pi and NaOH-Pi forms, whereas in the NCPR treatment the H2SO4-Pi fraction was depleted. No significant depletion of any P fraction was observed in the unfertilised soils as plants were very small and P change in the soil slices was below that which could be measured using the experimental technique. Suggestions are made on how the experimental technique could be improved.
Multiple paternity and communal maternal care in the feathertail glider (Acrobates pygmaeus)
Authors: Parrott Marissa L. , Ward Simon J. , Taggart David A.
Published: April 2005

It has been predicted, on the basis of morphological and behavioural evidence, that female feathertail gliders (Acrobates pygmaeus) will mate with multiple males within a single oestrus and that multiple paternity may occur in their litters. To determine whether feathertail glider litters are sired by multiple males, DNA collected from 10 litters and their mothers was tested for hereditary polymorphisms. The techniques used to evaluate paternity included AFLP (amplified fragment length polymorphisms), RAPD (randomly amplified polymorphic DNA) and RAMP (randomly amplified microsatellite polymorphisms) analyses and microsatellite markers. Although most genetic techniques produced only monomorphic bands, analyses with AFLPs indicated that multiple paternity did occur in six of eight litters, confirming that multiple mating within a single oestrous period occurs in this species. Results further indicated that mothers care for young other than their own. On the basis of their high testes-to-bodyweight ratio, male-biased sexual size dimorphism and multiple paternity in litters, sperm competition is considered highly likely to occur in this species.
Seasonal changes in the diet of the long-nosed bandicoot (Perameles nasuta) assessed by analysis of faecal scats and of stable isotopes in blood
Authors: Thums Michele , Klaassen Marcel , Hume Ian D.
Published: April 2005

The diet of long-nosed bandicoots (Perameles nasuta) on the central coast of New South Wales, Australia, was examined over two summers and two winters using a combination of faecal scat analysis for food fragments and stable isotope analysis (ratios of 13C/12C and 15N/14N) of blood. Isotope ratios in blood overlapped most strongly with those in invertebrate prey, and varied much less between seasons than did those in most dietary items, suggesting that the assimilated diet of long-nosed bandicoots is dominated by invertebrates throughout the year. Invertebrate remains dominated collected faeces in both seasons, even though the availability of invertebrate prey was higher in summer. Thus both techniques indicated that long-nosed bandicoots were primarily insectivorous year-round. Faecal scat analysis indicated that invertebrate eggs were more abundant in summer than winter. At a finer scale, spiders, orthopterans, lepidopteran larvae, ants, leaf material (non-grass monocot) and seeds were more abundant in summer, while cicada larvae, roots, fungi, grass leaves and Acacia bract (small modified leaves appearing as scales) were more abundant in winter. Subterranean foods (cicada larvae, plant roots and hypogeous fungi) were more abundant in winter and more abundant in the diet of males than of either lactating or non-lactating females.
RNA interference improves motor and neuropathological abnormalities in a Huntington's disease mouse model
Authors: Harper Scott Q. , Staber Patrick D. , He Xiaohua , Eliason Steven L. , Martins Inês H. , Mao Qinwen , Yang Linda , Kotin Robert M. , Paulson Henry L. , Davidson Beverly L.
Published: April 2005

Huntington's disease (HD) is a fatal, dominant neurogenetic disorder. HD results from polyglutamine repeat expansion (CAG codon, Q) in exon 1 of
HD
, conferring a toxic gain of function on the protein huntingtin (htt). Currently, no preventative treatment exists for HD. RNA interference (RNAi) has emerged as a potential therapeutic tool for treating dominant diseases by directly reducing disease gene expression. Here, we show that RNAi directed against mutant human htt reduced htt mRNA and protein expression in cell culture and in HD mouse brain. Importantly, htt gene silencing improved behavioral and neuropathological abnormalities associated with HD. Our data provide support for the further development of RNAi for HD therapy.
CcbP, a calcium-binding protein from
Anabaena
sp. PCC 7120, provides evidence that calcium ions regulate heterocyst differentiation
Authors: Zhao Yinhong , Shi Yunming , Zhao Weixing , Huang Xu , Wang Donghui , Brown Neil , Brand Jerry , Zhao Jindong
Published: April 2005

Although it is known that calcium is a very important messenger involved in many eukaryotic cellular processes, much less is known about calcium's role in bacteria. CcbP, a Ca
2+
-binding protein, was isolated from the heterocystous cyanobacterium
Anabaena
sp. PCC 7120, and the
ccbP
gene was cloned and inactivated. In the absence of combined nitrogen, inactivation of
ccbP
resulted in multiple contiguous heterocysts, whereas overexpression of
ccbP
suppressed heterocyst formation. Calmodulin, which is not present in
Anabaena
species, could also suppress heterocyst formation in both
Anabaena
sp. PCC 7120 and
Anabaena variabilis
. HetR induction upon nitrogen step-down was slow in the strain overexpressing
ccbP
. The Ca
2+
reporter protein obelin was used to show that mature heterocysts had a high intracellular free Ca
2+
concentration {[Ca
2+
]
i
}, and immunoblotting showed that CcbP was absent from heterocysts
.
A regular pattern of cells with higher [Ca
2+
]
i
was established during heterocyst differentiation before the appearance of proheterocysts. A rapid increase of [Ca
2+
]
i
could be detected 4 h after the removal of combined nitrogen, and this increase was suppressed by excessive CcbP. These results suggest that Ca
2+
ions play very important roles in
hetR
induction and heterocyst differentiation.
Publications as a measure of scientific advancement and of scientists' productivity
Authors: Daniel Hans‐Dieter
Published: April 2005

Robert Merton's norm of communalism states that academic scientists are obliged to publish their research findings; in order to ensure that credible knowledge is published, peer review is used for pre‐publication evaluation of manuscripts. The present system of journal peer review has, however, been much criticized. The paper summarizes research on reliability, fairness and predictive validity of journal peer review. The review of the research literature concludes that journal peer review is valid and does in fact function as a quality filter. However, since there is a lot of ambiguity in the literature as well, pre‐publication peer review should be supplemented with post‐publication evaluation to find out which publications and scientists have contributed most to the scientific advancement.
HighWire Press: ten years of publisher‐driven innovation
Authors: Sack John
Published: April 2005

An account is given of the beginnings and development of HighWire Press at Stanford University and the philosophy that sustains it.
The European physics publications scene: avant‐garde and traditionalism
Authors: Montonen Claus
Published: April 2005

An account is given of the background to current developments in the publication of research in physics, the current position and likely developments.
Institutional repositories: is the open access door half open or half shut?
Authors: MP Evan Harris
Published: April 2005

The response of the UK Government to the Report on science publishing by the Science and Technology Select Committee of the House of Commons is criticized for failing to take the necessary action to research or help catalyse a change in the publishing model. The initiatives of the National Institutes of Health and the Wellcome Foundation in setting up central archives are examined and their utility questioned. The evidence base for a change to open access is explored.
Ecological speciation in tropical reef fishes
Authors: Rocha Luiz A , Robertson D. Ross , Roman Joe , Bowen Brian W
Published: April 2005

The high biodiversity in tropical seas provides a long-standing challenge to allopatric speciation models. Physical barriers are few in the ocean and larval dispersal is often extensive, a combination that should reduce opportunities for speciation. Yet coral reefs are among the most species-rich habitats in the world, indicating evolutionary processes beyond conventional allopatry. In a survey of mtDNA sequences of five congeneric west Atlantic reef fishes (wrasses, genus
Halichoeres
) with similar dispersal potential, we observed phylogeographical patterns that contradict expectations of geographical isolation, and instead indicate a role for ecological speciation. In
Halichoeres bivittatus
and the species pair
Halichoeres radiatus
/
brasiliensis
, we observed strong partitions (3.4% and 2.3% divergence, respectively) between adjacent and ecologically distinct habitats, but high genetic connectivity between similar habitats separated by thousands of kilometres. This habitat partitioning is maintained even at a local scale where
H. bivittatus
lineages are segregated between cold- and warm-water habitats in both Bermuda and Florida. The concordance of evolutionary partitions with habitat types, rather than conventional biogeographical barriers, indicates parapatric ecological speciation, in which adaptation to alternative environmental conditions in adjacent locations overwhelms the homogenizing effect of dispersal. This mechanism can explain the long-standing enigma of high biodiversity in coral reef faunas.
Stress fields of a spheroidal inhomogeneity with an interphase in an infinite medium under remote loadings
Authors: Duan H.L , Wang J , Huang Z.P , Zhong Y
Published: April 2005

This paper presents the elastostatic solution of the problem of an arbitrarily oriented spheroidal inhomogeneity with an interphase embedded in an infinite medium. The latter is under a remote axisymmetric loading. The complete solution of this problem requires three fundamental solutions, which are obtained by the Papkovich–Neuber displacement potentials and the expansion formulae for spheroidal harmonics. New displacement potentials are given when the remote loading is a longitudinal shear. The influence of the orientation and aspect ratio of the inhomogeneity, and of the remote stress ratio on the stress concentrations at the interfaces and the von Mises equivalent stress in the inhomogeneity, are studied. It is found that the interphase between the inhomogeneity and the surrounding medium significantly alters the stress distribution in, and around, the inhomogeneity. In addition to the general solution for an inhomogeneity with an interphase, the stress field exterior to a spheroidal inhomogeneity without an interphase (the Eshelby problem) is presented in a simple form. It is pointed out that the solution of a spheroidal inhomogeneity with an interphase in an infinite medium subjected to an arbitrary uniform eigenstrain, or a combination of a uniform eigenstrain and an arbitrary remote mechanical loading, can be obtained using the procedure developed in this paper.
Cadherins in maternal–foetal interactions: red queen with a green beard?
Authors: Summers Kyle , Crespi Bernard
Published: April 2005

Cadherins are homophilic cell surface adhesion proteins, some of which mediate interactions between maternal and foetal tissues during mammalian pregnancy. David Haig suggested that these proteins may exhibit ‘green-beard gene’ effects, whereby the nature of binding between identical alleles in mother and foetus leads to differential levels of resource transfer. The selfish effects of such self-recognizing alleles should, however, be suppressed over evolutionary time by unlinked genes, which is expected to lead to antagonistic coevolution between placentally expressed cadherins and unlinked modifiers. Such molecular coevolution should leave a signature of positive selection, with high ratios of non-synonymous to synonymous amino acid substitution. We present evidence that three placentally expressed cadherin genes, E-cadherin, P-cadherin and VE-cadherin, have been subject to positive selection. By contrast, a ‘control’ cadherin that is not expressed in the placenta, H-cadherin, showed no evidence of selection. These results provide support for the hypothesis that the cadherin genes involved in maternal–foetal interactions have been subject to green-beard-effect mutations over the course of evolutionary history, leading to antagonistic coevolution with suppressing elements from the parliament of genes.
The dynamics of genetic and morphological variation on volcanic islands
Authors: Gübitz Thomas , Thorpe Roger S , Malhotra Anita
Published: April 2005

Oceanic archipelagos of volcanic origin have been important in the study of evolution because they provide repeated natural experiments allowing rigorous tests of evolutionary hypotheses. Ongoing volcanism on these islands may, however, affect the evolutionary diversification of species. Analysis of population structure and phylogeographic patterns in island populations can provide insight into evolutionary dynamics on volcanic islands. We analysed genetic and morphological variation in the gecko
Tarentola boettgeri
on the island of Gran Canaria and compared it with
Tarentola delalandii
on Tenerife, a neighbouring volcanic island of similar age but distinctly different geological past. Intraspecific divergence of mitochondrial haplotypes indicates long-term persistence of
Tarentola
on each island, with a phylogeographic signal left by older volcanic events. More recent volcanic eruptions (approximately 0.2 million years ago on Tenerife, approximately 2.2 million years ago on Gran Canaria) have left a signature of population expansion in the population genetic structure, the strength of which depends on the time since the last major volcanic eruption on each island. While these stochastic events have left traces in morphological variation in Tenerife, in Gran Canaria geographical variation was solely associated with environmental variables. This suggests that historically caused patterns in morphology may be overwritten by natural selection within 2 million years.
Food resource partitioning and trophic morphology of Brevoortia gunteri and B. patronus
Authors: Castillo‐Rivera M. , Kobelkowsky A. , Zamayoa V.
Published: April 2005

The menhadens Brevoortia gunteri and B. patronus are sympatric and morphologically similar. The two species are planktophagous and exhibited significant (P < 0·0001) food resource partitioning, with phytoplankton predominating in B. patronus stomachs and zooplankton in B. gunteri. The branchial apparatus of both species is of the typical alosine form. Brevoortia patronus has significantly more branchiospinules per mm (x̄=19·47) and significantly longer gill rakers (x̄=13·35 mm) than B. gunteri (x̄=14·11, x̄=12·01 mm respectively). B. patronus is characterized by a gill raker system forming a fine‐meshed filter capable of retaining smaller food items. The results support the hypothesis that food resource partitioning is related to different morphological features of the branchial apparatus.
Characterization of mitotic chromosomes of four species of the genus Diplodus: karyotypes and chromosomal nucleolar organizer region phenotypes
Authors: Vitturi R. , Libertini A. , Mazzola A. , Colomba M. S. , Sara G.
Published: April 2005

Karyotypes have been described in four Mediterranean species of the genus Diplodus (Teleostei, Sparidae), D. vulgaris, D. puntazzo, D. sargus and D. annularis. Chromosomes were mainly acrocentric in all but D. vulgaris, where certain chromosome pairs were subtelocentric. A remarkable intraspecific heteromorphism in the number of NOR‐bearing chromosomes along with a substantial interspecific variability in position of chromosomal Ag signals have been encountered. The presumed origin of multiple NOR‐bearing chromosomes in Diplodus species and variation of the NOR location is discussed.
Seasonal distribution of juvenile Atlantic cod in the southern Gulf of St Lawrence
Authors: Hanson J. M.
Published: April 2005

Seasonal changes in the geographic distribution of juvenile (ages 1–4) Atlantic cod Gadus morhua were determined from research surveys conducted in the southern Gulf of St Lawrence during 1986–87, 1990–91, and 1994. From late June to early October, juvenile cod were most abundant in shallow water (<50 m deep). By early November, all age groups (adults and juveniles) had migrated to deep (>100 m) offshore waters for the winter. For most juveniles, this represented a minimum migration of >225 km (each way). Age 3 and 4 cod migrated greater distances than age 1 and 2 fish. Some age 3 and 4 cod migrated as far as 650 km from their summer and early autumn areas. Although there was partial geographic segregation of juvenile and adult fish during summer and winter, all age groups were found together during the migration. No cod were present in the shallow waters (<80 m deep) of the south‐western Gulf during April due, in part, to later than average ice‐melt. Large numbers of all age‐classes were present in most of the south‐eastern Gulf by mid‐May.
Basal expansion of anal‐fin rays: a new osteological character in weakly discharging electric fish (Mormyridae)
Authors: Brown B. , Benveniste L. M. , Moller P.
Published: April 2005

Bone expansion of anal‐fin rays in mormyrid fish is introduced as a new osteological character to distinguish two mormyrid species, Brienomyrus brachyistius from Nigeria and Brienomyrus kingsleyae from Gabon. This character is sexually dimorphic and species‐specific, affecting the bases of anal‐fin rays in adult males only. Between the two species, it differed in degree, the number of rays involved, and the number of the first ray affected. These differences together with differences in conventional meristic and morphometric characters further support ongoing revisions of Brienomyrus taxonomy.
Salinity relationships in a freshwater population of eastern mosquitofish
Authors: Nordlie F. G. , Mirandi A.
Published: April 2005

Tolerance limit to elevated ambient salinity, and plasma osmotic regulatory capabilities were evaluated in a freshwater population of Gambusia holbrooki. The upper tolerance limit of ambient salinity was found to be 25‰. Plasma osmotic concentrations trended sharply upward with increasing salinity, but in a stepwise fashion, unlike patterns in related, but more euryhaline species. These laboratory observations are consistent with field observations that natural populations of G holbrooki are generally restricted to fresh and dilute brackish waters.
Reproductive segregation among the Barbus intermedius complex of Lake Tana, Ethiopia. An example of intralacustrine speciation?
Authors: Nagelkerke L. A. J. , Sibbing F. A.
Published: April 2005

Reproductive segregation among the large barbs Barbus intermedius complex, Cyprinidae, of Lake Tana, Ethiopia, was investigated in the mouths and upstream reaches of rivers tributary to the lake, during the spawning seasons of 1993 and 1994. The percentage of running fish of four Barbus morphotypes [Acute (Ac), Bigmouth big‐eye (Be), Intermedius (In), and Shorthead (Sh)] peaks with the highest water level of the lake. Large differences are apparent in the minimum fork length of running fish among morphotypes [c. 12 cm for male Sh and 28 cm for male Bigmouth small‐eye (Se)]. Significant differences occur in temporal, but especially in spatial patterns of the relative abundance of running morphotypes, when the lake is compared with the four major river mouths and their upstream reaches. These different relative abundances are clearest among Ac, Be, In, Sh and Troutlike (Tr). Also, the absence from the rivers of some morphotypes that are usually abundant in the lake itself [Barbel (Ba), Dark (Da), Lip (Li), and Zurki (Zu)], and the abundant presence in the rivers of Tr, rare in the lake, strengthen the hypothesis that spatial and/or temporal spawning segregation is present among the morphotypes. There are indications that Bighead (Bh) and Zu spawn in the lake itself, while other morphotypes were only found running in or near rivers. Combined with the morphological, ecological, and genetic differences, these data suggest the existence of several Barbus species, forming a unique species flock, which probably evolved within the lake. The presence of several, instead of one Barbus species complicates management of sustainable fisheries and protection of the lake's biodiversity. Present results show the importance of the rivers for Barbus reproduction and stress the urgent need for careful management of fishing activities in spawning times and areas.
Gill filaments of Liza ramada, a biotope for ectoparasites: surface area acquisition using image analysis and growth models
Authors: Caltran H. , Silan P.
Published: April 2005

Ecology of plant or animal communities requires knowledge of the biotope structure of these organisms. In the case of parasitic communities, the organs of a host constitute heterogeneous biotopes. Fish gills are an example of this, but their heterogeneity is not often considered. The gills of the mullet Liza ramada are such a biotope for several ectoparasites. Parasite density is an important factor in the study of fish‐parasite interactions, but cannot be determined if the colonized surface area of the gills is not known. The number of primary filaments, and therefore the surface area potentially colonized, is subject to variation with age. Assessment of the colonizable area raises specific problems of estimation. A new method taking into account surface areas of primary filaments and using image‐processing techniques is proposed. Models related to the increase of filament number and colonizable gill area as functions of the fish fork length are proposed. The increase of primary lamellae number with fish length can be fitted by an exponential‐type model and the accompanying increase in size of the colonizable gill area by A polynomial‐type model.
Endocrine, osmoregulatory, respiratory and haematological parameters in flounder exposed to the water soluble fraction of crude oil
Authors: Alkindi A. Y. A. , Brown J. A. , Waring C. P. , Collins J. E.
Published: April 2005

Flounders Pleuronectes flesus with an implanted vascular catheter were exposed to a 50% dilution of the water soluble fraction (WSF) of Omani crude oil (c. 6ppm total aromatic hydrocarbons) and serial blood samples taken to determine their endocrine status (cortisol, catecholamines and thyroid hormones) and the resultant and/or causal physiological (haematological, ionoregulatory and respiratory) disturbances. This resulted in a progressive increase in plasma cortisol concentrations from 3 h onwards (rising from 18 to 51 ng ml−1 after 48‐h exposure), and increased plasma glucose concentrations indicating a generalized stress response. Plasma T3 and T4 concentrations of both control and WSF‐exposed groups declined progressively over the experimental period; exposure to the WSF of crude oil further depressed plasma T4 concentrations but not plasma T3 concentrations relative to those of control fish. Plasma osmolality and sodium and chloride concentrations were stable in WSF‐exposed fish, however, plasma potassium concentrations were increased significantly at the 24‐and 48‐h sampling points. The most profound physiological disturbance in WSF‐exposed fish was a dramatic decline in blood oxygen content (CvO2) (from 2–8 to 0–8 ml 100 ml−1 after 48‐h exposure), which is likely to be the cause of the increased plasma noradrenaline concentrations from 3 h onwards. Increased noradrenaline is likely in turn to have been responsible for the significant increase in blood haematocrit and blood haemoglobin at the 3‐h sampling point, although the dominant effect in the longer‐term was a significant decline in both of these haematological parameters.
The effects of starvation on plasma free amino acid and glucose concentrations in lake sturgeon
Authors: Gillis T. E. , Ballantyne J. S.
Published: April 2005

The effect of starvation on the metabolism of the lake sturgeon Acipenser fulvescens was examined by measuring haematocrit, plasma glucose concentrations, and plasma free amino acids. Plasma was sampled on day 0, 10, 20, 45 and 60 of a 60‐day starvation period. Haematocrit was observed to decrease with starvation indicating a decreased oxygen carrying capacity of the blood. Plasma glucose levels differed only at day 10, with a decrease in blood glucose level in the starved group. No differences were detected between groups for alanine, aspartate, and serine, while elevated levels were observed for glutamine throughout the experiment. An increase in arginine, tyrosine, valine, methionine, tryptophan, phenylalanine, glutamate, glycine, isoleucine, histidine and leucine, concentrations were observed after 45 days of starvation. The maintenance, or increased plasma levels, of glucogenic amino acids in combination with the maintenance of blood glucose concentrations indicates active gluconeogenic processes in the liver supported by muscle proteolysis.
Primary and secondary thrombocytosis in childhood
Authors: Dame Christof , Sutor Anton Heinz
Published: April 2005

This review summarizes current data on the pathomechanisms and clinical aspects of primary and secondary thrombocytosis in childhood. Primary thrombocytosis is extremely rare in childhood, mostly diagnosed at the beginning of the second decade of life. As in adults, the criteria of the Polycythemia Vera Group are appropriate to diagnose primary thrombocytosis. The pathomechansims of non‐familial forms are complex and include spontaneous formation of megakaryopoietic progenitors and increased sensitivity to thrombopoietin (Tpo). Familial forms can be caused by mutations in Tpo or Tpo receptor (c‐mpl) genes. These mutations result in overexpression of Tpo, sustained intracellular signalling or disturbed regulation of circulating Tpo. Treatment of primary thrombocytosis is not recommended if platelet counts are <1500/nl and bleeding or thrombosis did not occur in patient's history. In severe cases, decision on treatment should weigh potential risks of treatment options (hydroxyurea, anagrelide) against expected benefits for preventing thrombosis or haemorrhage. Secondary thrombocytosis is frequent in children, in particular in the first decade of life. Hepatic Tpo production is stimulated in acute response reaction to a variety of disorders. Thrombosis prophylaxis is not required, even at platelet counts >1000/nl, except for cases with additional prothrombotic risk factors.
Gaucher disease: pathological mechanisms and modern management
Authors: Jmoudiak Marina , Futerman Anthony H.
Published: April 2005

Gaucher disease, the most common lysosomal storage disorder, is caused by the defective activity of the lysosomal enzyme, acid‐β‐glucosidase (GlcCerase), leading to accumulation of glucosylceramide (GlcCer), particularly in cells of the macrophage lineage. Nearly 200 mutations in GlcCerase have been described, but for the most part, genotype‐phenotype correlations are weak, and little is known about the down‐stream biochemical changes that occur upon GlcCer accumulation that result in cell and tissue dysfunction. In contrast, the clinical course of Gaucher disease has been well described, and at least one treatment is available, namely enzyme replacement therapy. One other treatment, substrate reduction therapy, has recently been marketed, and others are in early stages of development. This review, after discussing pathological mechanisms, evaluates the advantages and disadvantages of existing therapies.
Heterogeneous expression pattern of pro‐ and anti‐apoptotic factors in myeloid progenitor cells of patients with severe congenital neutropenia treated with granulocyte colony‐stimulating factor
Authors: Cario Gunnar , Skokowa Julia , Wang Zheng , Bucan Vesna , Zeidler Cornelia , Stanulla Martin , Schrappe Martin , Welte Karl
Published: April 2005

Apoptosis is accelerated in the myeloid progenitor cells of patients with severe congenital neutropenia (CN). Granulocyte colony‐stimulating factor (G‐CSF) increases neutrophil numbers in most CN patients. The effect of G‐CSF on apoptosis in CN was analysed by apoptosis rate and expression of anti‐ and pro‐apoptotic factors. G‐CSF‐treated patients showed higher apoptosis frequency, lower expression of bcl‐2 and bcl‐xL, but higher expression of bfl‐1/A1 and mcl‐1. Caspase 9 was highly expressed in patients and controls after G‐CSF administration. Thus, G‐CSF acts on apoptosis regulation, but additional mechanisms leading to the increase of neutrophil numbers must be assumed.
Teicoplanin‐dependent antibodies: detection and characterization
Authors: Garner Stephen F. , Campbell Kate , Smith Graham , Hurd Colin , Davidson Simon J. , Treacy Marilyn , Burman John F. , Kroll Hartmut , Ouwehand Willem H.
Published: April 2005

There are only a few reports of thrombocytopenia associated with clinical doses of teicoplanin, a glycopeptide antibiotic used against Gram‐positive bacteria. We investigated 39 patients receiving teicoplanin; 31 were thrombocytopenic with platelet counts between 1–105 × 109/l and 8 were not thrombocytopenic. We identified 14 thrombocytopenic cases (45%) and two (25%) non‐thrombocytopenic cases with IgG teicoplanin‐dependent platelet‐reactive antibodies. Use of glycoprotein (GP) capture enzyme‐linked immunosorbent assay with platelets and GPIIb/IIIa transfected Chinese Hamster Ovary cells as well as flow cytometry with GP‐deficient platelets indicated that the GPIIb/IIIa complex is a major target antigen of these antibodies.
Cellular drug sensitivity in MLL‐rearranged childhood acute leukaemia is correlated to partner genes and cell lineage
Authors: Palle J. , Frost B. M. , Forestier E. , Gustafsson G. , Nygren P. , Hellebostad M. , Jonsson O. G. , Kanerva J. , Schmiegelow K. , Larsson R. , Lönnerholm G. ,   on behalf of the Nordic Society for Paediatric Haematology and Oncology
Published: April 2005

Rearrangements in the 11q23 region, the site of the mixed lineage leukaemia (MLL) gene, are found in both childhood acute myeloid (AML) and lymphoblastic (ALL) leukaemia. We studied the in vitro drug resistance by the fluorometric microculture cytotoxicity assay (FMCA) in 132 children with AML and 178 children with ALL (aged 0–17 years). In AML, children with t(9;11) (n = 10) were significantly more sensitive to cytarabine (P < 0·001) and doxorubicin (P = 0·005) than non‐11q23 rearranged patients (n = 108). Children with other 11q23 rearrangements (n = 14) differed less from non‐rearranged children. The ‘AML‐profile’ common to all three groups included relative resistance to glucocorticoids and vincristine. In ALL, children with 11q23 rearrangement (n = 22) were significantly more sensitive to cytarabine (P = 0·026) than children without 11q23 rearrangement (n = 156), also after stratification for white blood cell count. In conclusion, the findings indicate that the cellular drug resistance is correlated to both the cell lineage and the type of 11q23 rearrangement. High cellular sensitivity to cytarabine and doxorubicin might explain the excellent treatment results in children with AML and t(9;11). The present study supports the strategy of contemporary protocols to include high‐dose cytarabine in the treatment of 11q23‐positive patients both in AML and ALL.
Anti‐prothrombin IgG from patients with anti‐phospholipid antibodies inhibits the inactivation of factor Va by activated protein C
Authors: Galli Monica , Willems George M. , Rosing Jan , Janssen Rita M. , Govers‐Riemslag José W. P. , Comfurius Paul , Barbui Tiziano , Zwaal Robert F. A. , Bevers Edouard M.
Published: April 2005

Interference of anti‐phospholipid antibodies with the protein C pathway has been suggested to play a role in the development of thrombosis in the anti‐phospholipid syndrome. We studied the effect of IgG preparations containing anti‐prothrombin antibodies of 17 lupus anticoagulant‐positive patients and 12 controls on the inactivation of factor Va (FVa) by activated protein C (APC) in a system with purified coagulation factors. Test IgG was incubated with human prothrombin, phospholipid vesicles and CaCl2. Protein S, FVa and APC were added and the APC‐dependent loss of FVa activity was monitored over time. The residual amount of FVa remaining after 10 min was 14 ± 4% (mean ± SD) when 1·5 mg/ml normal IgG was present and ranged between 17% and 82% with 1·5 mg/ml patient IgG. Twelve patients IgG gave values of residual FVa >22% (i.e. 2 SD above the mean of controls), indicating that APC‐mediated inactivation of FVa was significantly inhibited. The inhibition was strictly dependent on the presence of prothrombin, proportional to the concentration of IgG and strongly diminished at a 20‐fold higher phospholipid concentration. Most, although not all, IgG containing anti‐prothrombin antibodies inhibit the APC‐catalysed FVa inactivation, which may contribute to the increased risk of thrombosis in patients with the anti‐phospholipid syndrome.
Bone marrow endothelial cells in multiple myeloma secrete CXC‐chemokines that mediate interactions with plasma cells
Authors: Pellegrino Antonio , Ria Roberto , Pietro Giulia Di , Cirulli Teresa , Surico Giammarco , Pennisi Angela , Morabito Fortunato , Ribatti Domenico , Vacca Angelo
Published: April 2005

Bone marrow endothelial cells (EC) from patients with multiple myeloma (MM) were found to express and secrete higher amounts of the CXC‐chemokines CXCL8/interleukin (IL)‐8, CXCL11/interferon‐inducible T‐cell alpha chemoattractant (I‐TAC), CXCL12/stromal cell‐derived factor (SDF)‐1α, and CCL2/monocyte chemotactic protein(MCP)‐1 than EC from human umbilical vein (HUVEC), considered as a healthy counterpart. Paired plasma cells and several MM cell lines expressed cognate receptors of each chemokine to a variable extent. When cells were exposed to chemokines, CXCL8/IL‐8 and CXCL12/SDF‐1α stimulated their proliferation and all chemokines stimulated cell chemotaxis. It is suggested that angiogenesis also favours MM progression through the release of CXC‐chemokines.
Nicotinic acetylcholine receptor‐mediated stimulation of endothelial cells results in the arrest of haematopoietic progenitor cells on endothelium
Authors: Serobyan Naira , Schraufstatter Ingrid U. , Strongin Alex , Khaldoyanidi Sophia K.
Published: April 2005

The function of endothelial cells that contribute to the regulation of haematopoietic stem/progenitor cells (HSPC) migration from peripheral blood into bone marrow can be influenced by extrinsic factors including nicotine. Therefore, the effect of nicotine on HSPC extravasation was studied. Using a parallel laminar flow chamber, we demonstrated an increase in the number of HSPC adhering to the nicotine‐exposed endothelium under conditions of physiological shear stress in vitro. Nicotine‐induced adhesion of HSPC was inhibited by mecamylamine, a non‐selective nicotinic acetylcholine receptor (nAchR) antagonist. The enhanced adhesive interactions of HSPC with nicotine‐exposed endothelial monolayers coincided with the nicotine‐induced activation of endothelial cells. Nicotine induced fast cytoskeletal reorganization and formation of filopodia in endothelial cells through interaction with the non‐neuronal nAchR expressed by these cells. In addition, nicotine treatment stimulated rapid phosphorylation of Erk1/2 and p‐38 in endothelial cells. Finally, nicotine inhibited the stroma derived factor‐1‐mediated transendothelial migration of HSPC. Decreased migration of HSPC correlated with diminished matrix metalloproteinase‐9 activity secreted by bone marrow cells and decreased expression of CD44 on the surface of endothelial cells. Overall, our data suggest that exposure to nicotine causes endothelial cell dysfunction and leads to the pathological arrest of HSPC on endothelium, interfering with their proper migration process.
Primary school students' perceptions of interactive whiteboards
Authors: Hall Ian , Higgins S
Published: April 2005

Abstract
Students involved in the interactive whiteboard (IWB) evaluation, sponsored by the Centre for British Teachers (CfBT), were interviewed in regard to their perceptions about IWBs. Twelve group interviews (72 students) were conducted between January and Easter 2004 with Year 6 students (between 10 and 11 years of age) in six Local Education Authority (LEA) areas located in the North and South of England. Students were very enthusiastic about particular aspects of IWBs, such as their versatility in the classroom, multimedia capabilities and the fun and enjoyment they brought to learning. Students also highlighted, however, technical problems, teacher and students' information and communication technology skills and students' lack of access to the technology as negative aspects.
Using computer conferencing and case studies to enable collaboration between expert and novice teachers
Authors: Winter Eileen C. , McGhie‐Richmond Donna
Published: April 2005

Abstract
This paper reports on a teaching innovation where groups of experienced and novice teachers collaborated in analyzing case studies involving the education of students with special learning needs. The teachers collaborated in an asynchronous computer conferencing system (Web Knowledge Forum). All participants were enrolled in special education graduate courses taught by the authors. The authors discuss the use of case studies in teacher education, collaboration between novice and expert teachers, and highlight some of the demands of computer conferencing particularly in relation to the loss of face‐to‐face interactions and the interpretive demands of electronic communication.