bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leptodora kindti and Flexible Foraging Behaviour of Fish – Factors behind the Delayed Biomass Peak of Cladocerans in Lake Hiidenvesi
Authors: Uusitalo Laura , Horppila Jukka , Eloranta Pertti , Liljendahl‐Nurminen Anne , Malinen Tommi , Salonen Mikko , Vinni Mika 
Published: June 2004

AbstractIn the eutrophic L. Hiidenvesi, the spring biomass maximum of cladoceran zooplankton is missing and the highest biomass takes place in July–August. The factors behind the delayed biomass peak were studied in four different basins of the lake with concomitant data on cladocerans assemblages, density of the predatory cladoceran Leptodora kindti and food composition of fish. In all the basins, the abundance of Leptodora peaked in June, being highest (up to 800 ind. m–3) in the two most shallow basins (max depth < 4 m). The duration of the high population density was short and in July‐August Leptodora density stayed below 200 ind. m–3, although the water temperature was still favourable. The collapse of the Leptodora population coincided with the change in the feeding habits of fish. In early summer, fish predation was targeted mainly on copepods and zoobenthos, while in high summer Leptodora was one of the main preys of perch, white bream and bleak. The biomass of herbivorous cladocerans was below 10 μg C l–1 in June, and climbed to a maximum in August in the two most shallow basins (34 and 76 μg C l–1), in July in the deepest basin (27 μg C l–1), and in September in the intermediate basin (55 μg C l–1). In the two most shallow basins, the death rate of the dominating cladoceran, Daphnia cristata, closely followed the food consumption rate by the Leptodora population. In the deeper basins, the agreement was not so close, smelts (Osmerus eperlanus) and chaoborids being important predators of herbivores. The duration of the period of high Leptodora density thus depended on the predation pressure by fish, while the increased fish predation on Leptodora in July–August allowed the elevation of the biomass of herbivorous cladocerans.
The Trophic Index of Macrophytes (TIM) – a New Tool for Indicating the Trophic State of Running Waters
Authors: Schneider Susanne , Melzer Arnulf 
Published: June 2004

AbstractIn running waters, apart from structural degradation, nutrient input becomes increasingly important. To investigate the indicator values of as many species of submerged macrophytes as possible numerous samples of the sediment within macrophyte stands and the overlying water were taken in running waters throughout Bavaria, Germany. To develop the Trophic Index of Macrophytes (TIM), the concentrations of soluble reactive phosphorus of both the water body and the sediment pore water were used. Based on a weighted sum of the SRP‐concentrations of the water body and the sediment pore water, indicator values were determined for a total of 49 species of submerged macrophytes. A detailed method is described on how and depending on which preconditions the trophic state of running waters can be determined by the TIM. An example of the TIM in the stream Rotbach is given. It shows that the TIM is a useful means to detect differences in the phosphorus loading of running waters.
Liver Changes Related to Oocyte Growth in Roach, a Single Spawner Fish, and in Bleak and White Bream, Two Multiple Spawner Fish
Authors: Rinchard Jacques , Kestemont Patrick 
Published: June 2004

AbstractThe objectives of this study were to compare the seasonal hepatic activity and to evaluate whether this activity was related to the dynamics of oocyte recruitment in three cyprinids from the River Meuse (Belgium): the roach Rutilus rutilus as a single spawner, and the bleak Alburnus alburnus and the white bream Blicca bjoerkna as multiple spawners. In roach, hepatosomatic index (HSI) was low during exogenous vitellogenesis. However, the strong development of the rough endoplasmic reticulum (RER), the presence of large mitonchondria with many inner folds, and the depletion of glycogen, lipid droplets and phospholipids indicated intense hepatic activity during that period. Prior to spawning, hepatic activity decreased as indicated by a decrease of the HSI and in the hepatocytes a regression of the RER and the disappearance of the lipid droplets and glycogen. In bleak, the oocyte recruitment occurred continuously throughout the spawning season and the vitellogenic activity of the liver remained intense throughout that period as suggested by high HSI and the ultrastructure of the hepatocytes. In contrast in white bream the vitellogenic activity of the liver decreased during the spawning season as the completion of the vitellogenesis took place prior to spawnings. We concluded that the vitellogenic activity of the liver is strongly related to oogenesis.
The Feeding Strategies of the Leech Erpobdella octoculata (L.): A Laboratory Study
Authors: Kutschera U. 
Published: June 2004

AbstractThe feeding behaviour of the freshwater leech Erpobdella octoculata was analysed by exposing potential invertebrate and vertebrate prey organisms (alive, wounded or dead) to leech attack in dishes, in the laboratory. The fact that E. octoculata is a macrophagous feeder that swallows living prey organisms whole (preferentially Chironomus larvae) is documented. However, it was repeatedly observed that adult leeches sucked the body fluids from wounded larvae. Likewise, cut pieces of earthworms, dead crustaceans and crushed water snails were attacked and the soft parts sucked in with the aid of the unarmed pharynx. Adult leeches sucked the body fluids from dead, decaying bodies of vertebrates (fish, newt larvae). Newly hatched young are blood suckers that rapidly attacked the wounded regions of Chironomus larvae and other invertebrates such as crushed water snails. It is concluded that the common leech E. octoculata is not only a predator, but also a fluid sucker and a scavenger. The ecological implications of this finding are discussed.
Macrophage responses to vascular stent coatings
Authors: Ball M. , O'Brien A. , Dolan F. , Abbas G. , McLaughlin J. A. 
Published: June 2004

AbstractDiamond‐like carbon (DLC) films have been proposed as potential coatings for blood‐contacting devices. In this study, tetrahedral amorphous carbon (ta‐C) films deposited by filtered cathodic vacuum arc system (FCVA) were compared with commercially deposited polyurethane coatings (PU) and uncoated stainless steel samples. X‐ray reflectivity (XRR) measurements were performed to check density and thickness of the ta‐C coatings, and contact angles measurements were used to assess surface wettability. J774 macrophages were used to assess the cell responses to the materials. Cell number, metabolic activity, and hydrogen peroxide production were measured by using biochemical assays, and the cell attachment and morphology were determined by using scanning electron microscopy and confocal laser scanning microscopy. Wettability measurements showed that of the materials, the stainless steel was the most hydrophilic, and the ta‐C coatings were the most hydrophobic. Although the initial attachment and morphology did not appear to be dependent on the wettability, the cell numbers did increase with increasing wettability. Macrophages on the stainless steel samples were the most active in producing hydrogen peroxide. These data show that ta‐C samples performed as well as commercial PU‐coated samples in blocking cell reactions to the substrate and may prove to be effective coatings for blood‐contacting materials. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 380–390, 2004
Metabolic pathways and physiological and pathological significances of lysolipid phosphate mediators
Authors: Tokumura Akira 
Published: June 2004

AbstractLysophosphatidic acid and sphingosine 1‐phosphate are structurally simple and physiologically very important lysophospholipids. Because they possess distinct structural backbones (glycerol and sphingosine, respectively), there are different metabolic pathways for their intracellular production. Recently, several key enzymes that produce or degrade these lysolipid phosphate mediators extracellularly have been characterized. This review focuses on the physiological and pathophysiological significances of the extracellular metabolic pathways involving recently characterized exo‐type lysophospholipase D, ecto‐type phospholipase A, and ecto‐type lipid phosphate phosphatase. © 2004 Wiley‐Liss, Inc.
Human skin‐derived stem cells migrate throughout forebrain and differentiate into astrocytes after injection into adult mouse brain
Authors: Belicchi Marzia , Pisati Federica , Lopa Raffaella , Porretti Laura , Fortunato Francesco , Sironi Manuela , Scalamogna Mario , Parati Eugenio A. , Bresolin Nereo , Torrente Yvan 
Published: June 2004

AbstractRecent evidence indicates that neural stem cell properties can be found among a mammalian skin‐derived multipotent population. A major barrier in the further characterization of the human skin‐derived neural progenitors is the inability to isolate this population based on expression of cell surface markers. Our work has been devoted to purified human skin‐derived stem cells that are capable of neural differentiation, based on the presence or absence of the AC133 cell surface marker. The enriched skin‐derived AC133+ cells express the CD34 and Thy‐1 antigens. These cells cultured in a growth medium containing epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) proliferate, forming spheres, and differentiate in vitro into neurons, astrocytes, and rarely into oligodendrocytes. Single cells from sphere cultures initiated from human purified AC133+ cells were replated as single cells and were able to generate new spheres, demonstrating the self‐renewing ability of these stem cell populations. Brain engraftment of cells obtained from human purified AC133+‐derived spheres generated different neural phenotypes: immature neurons and a most abundant population of well differentiated astrocytes. The AC133‐derived astrocytes assumed perivascular locations in the frontal cortex. No donor‐derived oligodendrocytes were found in the transplanted mouse brains. Several donor small, rounded cells that expressed endothelial markers were found close to the host vessel and near the subventricular zone. Thus, mammalian skin AC133‐derived cells behave as a multipotent population with the capacity to differentiate into neural lineages in vitro and, prevalently, endothelium and astrocytes in vivo, demonstrating the great plasticity of these cells and suggesting potential clinical application. © 2004 Wiley‐Liss, Inc.
Analysis of galactocerebrosidase activity in the mouse brain by a new histological staining method
Authors: Dolcetta D. , Perani L. , Givogri M.I. , Galbiati F. , Orlacchio A. , Martino S. , Roncarolo M.G. , Bongarzone E. 
Published: June 2004

AbstractGene therapy of galactocerebrosidase (GALC) deficient mice (Twitcher mutants) requires a fast and sensitive assay to detect transduced cells in vitro and in vivo. We have developed a new rapid histochemical method that specifically detects GALC activity in situ in neural cells using 5‐Br‐3Cl‐β‐galactopiranoside (X‐Gal) in the presence of taurodeoxycholic and oleic acids to enhance suspension of the substrate at low pH. Using this method, we observed robust X‐Gal staining in diverse neuronal populations and interfascicular oligodendrocytes in sections from normal mouse brain. In contrast, sections of Twitcher brain did not show a specific staining pattern in neurons or glial cells. The availability of this new sensitive and rapid in situ detection assay is fundamental for the follow‐up of Twitcher mice under gene or cellular therapies to correct central GALC deficiency. © 2004 Wiley‐Liss, Inc.
Wind tides in the Rio de la Plata estuary: Meteorological conditions
Authors: Escobar Gustavo , Vargas Walter , Bischoff Susana 
Published: June 2004

AbstractSynoptic situations associated with strong southeasterly winds over the Rio de la Plata (RP) estuary are locally known as sudestadas. This phenomenon affects the coast of Buenos Aires city and its outskirts with floods, normally accompanied with persistent rainfall.Storm surge levels (river level minus the astronomical tide levels) were used to identify cases associated with sudestadas. Although there is a local belief that most sudestadas are caused by cyclogenesis during winter, they actually occur during the whole year, being indeed less frequent in winter. In addition, they are not necessarily associated with cyclonic circulation. The maximum frequency of sudestadas is observed during summer and at the beginning of spring and autumn. This annual distribution was similar when two different water‐level thresholds were used to characterize the storm surge.The three principal components (PCs) of the atmospheric circulation field at 1000 hPa accompanying the sudestadas explain 75% of the variance. These patterns show that sudestadas are associated with either a combination of a high‐pressure system to the south of the RP and relatively low pressure to the north (first and second PC modes) or a very deep low‐pressure zone to the north of the river (third PC mode). These cases are associated with southeasterly winds, which produce tide waves on the RP.Almost all the sudestadas associated with the third PC occur in winter and they reach on average greater peak levels than the others. These cases are associated with an intense low‐pressure system north of the RP, which is typically due to the frequent cyclogenesis in that region. Copyright © 2004 Royal Meteorological Society
Differences in rainfall variability in the South and Southeast Asian summer monsoons
Authors: Zveryaev Igor I. , Aleksandrova Marina P. 
Published: June 2004

AbstractLong‐term rainfall variability in the South and Southeast Asian summer monsoons is investigated using observational data for a 50 year period. Linear trends indicate a general level of summer rainfall decrease over northeast India that has intensified during recent decades. In contrast to the South Asian Monsoon (SAM), there is no significant rainfall trend in the Southeast Asian Monsoon (SEAM).The result of the empirical orthogonal functions (EOFs) analysis has shown that the leading EOF modes explain about 25% of total rainfall variability in both regions. Low correlation between respective principal components implies that rainfall variations in the two monsoon subsystems are not related, suggesting that different mechanisms are responsible for the interannual rainfall variability in the SAM and the SEAM.The interannual variability of the SAM rainfall is linked to sea‐surface temperature (SST) fluctuations in the equatorial eastern Pacific during the monsoon season and the following autumn. As revealed by lead–lag correlations, the warming of the Arabian Sea and a region located northwest of Australia during the boreal winter may lead to a strong SAM. The interannual behaviour of the SAM rainfall shows a feature of the quasi‐biennial oscillation with the reversal of correlations between months preceding the monsoon and the monsoon–post‐monsoon months. In comparison with the SAM, the interannual variability of the SEAM rainfall is associated with distinctly different SST patterns. Enhanced SEAM rainfall is preceded by a high SST in the northern Indian Ocean and the South China Sea in the previous January and February. Significant correlations between the SEAM rainfall and SST, which form a tripole pattern in the North Pacific Ocean, are detected during the preceding winter and early spring, suggesting that wintertime tropics–extratropics interactions may play a role in the SEAM rainfall variability. Copyright © 2004 Royal Meteorological Society
Impact of a possible local wind change on the wave climate in the upper Río de la Plata
Authors: Dragani Walter C. , Romero Silvia I. 
Published: June 2004

AbstractThe aim of the present work is to give a quantitative assessment of the change in mean wave parameters in the upper Río de la Plata (RDP) by considering a possible change in local winds. A statistical analysis of the sea and swell in the outer RDP, as well as the computation and analysis of their propagation and transformation throughout the intermediate and upper regions, reveal that refraction, shoaling and friction effects diminish wave heights by 94.9%. Consequently, the predominant wave climate in the upper RDP could only be described considering wind waves generated locally (sea). The present wave climate (directional wave heights and periods) in the upper RDP is estimated by the hindcasting methodology based on 10‐year statistics of winds measured at ‘Aeroparque Jorge Newery’ meteorological station. A possible future scenario is sketched for which wind frequencies and intensities for the easterly directions are respectively 30% and 10% higher than the present values. The results for the upper RDP show that mean easterly wave heights will increase by 0.12 m (13%) relative to present values (0.90 m) and their frequencies will increase by 30% (from 18.4 to 23.9%), producing larger total heights. Therefore, the coast of Buenos Aires city will be more frequently exposed to wave effects, giving rise to intensified associated littoral processes. The mean period for easterly waves will not change significantly (less than 4%, from 5.3 to 5.5 s). The results obtained are a first approximation to the problem, suggesting that within the upper RDP the wave climate is very sensitive to the predicted change in the wind field. Copyright © 2004 Royal Meteorological Society
It never rains on Sunday: the prevalence and implications of untagged multi‐day rainfall accumulations in the Australian high quality data set
Authors: Viney Neil R. , Bates Bryson C. 
Published: June 2004

AbstractThe perception prevalent in the literature that Australian rainfall records are reasonably uncontaminated by untagged weekend accumulations is reassessed. An objective probabilistic test for untagged accumulations is developed and applied to 181 gauges that have previously been identified as having high‐quality data suitable for long‐term analyses of climate change. As many as 102 of these gauges are found to contain hidden, untagged accumulations, and the overall prevalence of untagged accumulations in the high‐quality data set is shown to be only slightly less than that of tagged accumulations. A simple study simulating the effects of accumulations in the records of the high‐quality data set shows that, in records (or parts of records) with frequent accumulations, rainfall probability, mean wet‐spell length and mean dry‐spell length can be underestimated by as much as 24%, 34% and 18% respectively, and that the magnitude of the potential prediction error in these variables (and also in indices of rainfall intensity extremes) at a site shows strong dependence on the rainfall probability. Selected published studies on climate change are reanalysed to account for the presence of untagged accumulations and to show that significant changes in long‐term trends can be obtained for individual locations. Copyright © 2004 Royal Meteorological Society
Atmospheric predictors for major floods in the Negev Desert, Israel
Authors: Kahana Ron , Ziv Baruch , Dayan Uri , Enzel Yehouda 
Published: June 2004

AbstractThe study examines the ability of a set of atmospheric variables to predict major floods in the Negev Desert in the southern part of Israel. The two dominant synoptic types, which contributed over 70% of the major floods during 1965–94 in that region, were examined. These are: the active Red Sea trough (ARST), a surface trough along the Red Sea, combined with a pronounced upper trough; and the Syrian low (SL), an intense Mediterranean cyclone centred over Syria.For each synoptic type, a set of atmospheric variables (predictors) was chosen to reflect its unique atmospheric features, and a prediction score was calculated as the ratio between the number of flood‐producing storms and the total number of events in which all the variables exceeded their threshold values.The prediction score for the ARST type is 86%. Moreover, the predictors identify the major flood dates without any ‘false’ date (100%) for 4 of the 5 months in which major floods of this type had occurred. Most of the predictors are found at the 500 hPa level, and the most powerful is the v/u ratio, which represents the southerly wind component and is responsible for the transport of moist tropical air masses (essential for convection) toward the Middle East. The prediction score for the SL type is 73%. The intensity and structure of the surface cyclone are found to be most powerful predictors, although the importance of geopotential height at 500 hPa indicates that these types of flood depend on the combined effect of several factors.Transforming these remarkably high scores into a high‐skill operational forecast of major floods in the Negev requires reliable forecast models to supply the desired variables with reasonable accuracy. It seems that the current operational models, together with our derived predictors, have the potential to yield a successful forecast of major floods 2 days in advance. Copyright © 2004 Royal Meteorological Society
Effects of El Niño–southern oscillation on southernmost South America precipitation at 53 °S revealed from NCEP–NCAR reanalyses and weather station data
Authors: Schneider Christoph , Gies Daniel 
Published: June 2004

AbstractMonthly mean records of climate data over southern South America from the National Centers for Environmental Prediction (NCEP)–National Center for Atmospheric Research (NCAR) reanalysis project (NNR) were processed to determine possible teleconnections of El Niño–southern oscillation with precipitation at 53 °S in the southernmost Andes. The NNR data used include precipitation rate, zonal wind speed and sea‐level pressure (SLP). All data were correlated to the southern oscillation index (SOI) allowing for time leads/time lags of up to 8 months.Significant positive correlation at the 99% level between SOI and SLP is obtained north of 40 °S (r= 0.4). SLP south of 58 °S negatively correlates with SOI (r= −0.3). In consequence, during El Niño events the SLP gradient over Patagonia decreases, leading to lower wind speeds. Precipitation on the west coast of Patagonia depends greatly on the strength of the west winds due to orographically induced precipitation. According to this, positive correlation (r= 0.4) between SOI and precipitation rate anomalies is found west of the Patagonian coastline between 45 and 55 °S based on annually averaged data. Precipitation decreases by about 15% during strong El Niños. The correlation decreases to insignificant values east of the Andes mountain range. Correlation between SLP gradient and SOI along the west coast of southern Patagonia is largest from austral spring to summer in year 0 of an El Niño event and in April of year +1. Correlations are particularly strong at a time lag of +1 and +2 months, with SOI leading the SLP gradient. Correlation was found to vary in time, with weak correlations during the 1970s and early 1980s and enhancing teleconnection towards the turn of the century. The generally weak positive correlation between precipitation and SOI was also found by comparing precipitation data from weather stations at 53 °S on the west coast of South America with SOI. Copyright © 2004 Royal Meteorological Society.