bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of groundwater flow paths in complex aquifer systems
Authors: Lamouroux Christian , Hani Azzedine
Published: June 2006

A methodology was developed and applied to the Tindouf (southwestern Algeria) and the Annaba–Bouteldja aquifers (northeastern Algeria) in order to understand better the hydrogeology of the complex aquifers despite the scarcity of the available data. Graphical representation of deuterium versus oxygen‐18 and principal components analysis (PCA) are statistical techniques used to combine various disciplinary data in order to identify chemical and isotopic groups, which are in turn used to define groundwater flow paths. The results of this study agree with the generally accepted hydrogeological conceptual model of the aquifers. In addition, we obtained new results using the PCA method: (1) a description of the complex flow system by grouping various qualitative and quantitative parameters; (2) the definition and characterization of the main groundwater flow paths from their sources to the discharge zones. These flow paths are defined by their water categories, which are represented by salinity and origin of groundwater. This approach is useful for analysing aquifers despite the lack of important database and may also be helpful for studying other complex groundwater basins. Copyright © 2006 John Wiley & Sons, Ltd.
Rates, processes and morphology of freshwater calving at Miage Glacier (Italian Alps)
Authors: Diolaiuti G. , Citterio M. , Carnielli T. , D'Agata C. , Kirkbride M. , Smiraglia C.
Published: June 2006

The rates and processes of freshwater calving at Miage Glacier (Mont Blanc Massif, Italy) are described. Calving at Miage Glacier has occurred for two centuries on its right‐lateral side, into a small ice‐marginal lake (Miage Lake). Field surveys identified the main processes leading to iceberg production and quantified the calving losses over a summer season. Calving losses were compared (1) with the surface ablation of the debris‐covered tongue, evaluated through a simple model based on measured ablation rates at different altitudes and debris cover thicknesses, and (2) with other inputs to the lake (stream inflow discharge) and with the lake volume. Results show that thermal undercutting by warmer surface water plays an important role in driving ice‐cliff evolution. Thermal notches grow at ∼30–35m year−1 and cause a similar amount of cliff retreat. Calving contributes ∼2% of the estimated summer runoff from the debris‐covered part of the ablation zone, but this is equivalent to ∼38% of the lake volume, and is of the same magnitude as the mean discharge from the inflow streams. These data indicate that calving of the ice cliff is one of the main water sources for maintaining the lake at the maximum summer volume, with the surface at the level of the subaerial outlet stream. A survey of Italian calving glaciers shows that calving is becoming more widespread, and that debris covers are present at all calving ice margins. The lake–ice interactions described in this study can, therefore, be considered to have wider representativeness. Copyright © 2006 John Wiley & Sons, Ltd.
Firn layer impact on glacial runoff: a case study at Hofsjökull, Iceland
Authors: de Woul Mattias , Hock Regine , Braun Matthias , Thorsteinsson Thorsteinn , Jóhannesson Tómas , Halldórsdóttir Stefanía
Published: June 2006

A mass balance–runoff model is applied to Hofsjökull, an 880 km2 ice cap in Iceland, in order to assess the importance of the firn layer for glacial runoff. The model is forced by daily temperature and precipitation data from a nearby meteorological station. Water is routed through the glacier using a linear reservoir model assuming different storage constants for firn, snow and ice. The model is calibrated and validated using mass balance data and satellite‐derived snow facies maps. Simulated mass balances and snowline retreats are generally in good agreement with observations. Modelled cumulative mass balance for the entire ice cap over the period 1987/1988 to 2003/2004 is − 7·3 m, with uninterrupted negative mass balances since 1993/1994. Perturbing the model with a uniform temperature (+1 K) and precipitation (+10%) increase yields static mass balance sensitivities of − 0·95 m a−1 and +0·23 m a−1 respectively. Removing the firn layer under otherwise likewise conditions results in almost unchanged total runoff volumes, but yields a redistribution of discharge within the year. Early summer discharge (June to mid August) is amplified by roughly 5–10%, whereas late‐summer/autumn discharge (mid August to November) is reduced by 15–20% as a result of accelerated water flow through the glacial hydrological system. In comparison, applying a climate‐model‐based temperature and precipitation scenario for Iceland until 2050 results in higher runoff throughout the year, increasing total runoff by roughly one‐third. The results emphasize the role of the firn layer in delaying water flow through glaciers, and the influence on discharge seasonality when firn areas shrink in response to climate‐change‐induced glacier wastage. Copyright © 2006 John Wiley & Sons, Ltd.
Snowmelt contribution to discharge from a large mountainous catchment in subarctic Canada
Authors: Woo Ming‐Ko , Thorne Robin
Published: June 2006

Snowmelt is responsible for much of the annual runoff and most of the peak discharges in subarctic mountainous regions. It also provides a significant amount of freshwater inflow to the polar seas, which has implications for Arctic Ocean circulation. Owing to considerable topographic contrasts in large mountainous basins, snow accumulation and melt patterns are highly variable in time and space, but the scarcity of data in these regions prevents the patterns from being discerned. Application of a macro‐scale hydrological model (using reanalysis data from the European Centre for Medium‐Range Weather Forecasts, the National Centers for Environmental Prediction and the North American Regional Reanalysis) offers one suitable approach to estimate the magnitude and timing of snowmelt contribution to discharge from large mountainous catchments. The Liard basin, subarctic Canada, is used as an example and the SLURP (Semi‐distributed Land‐use‐based Runoff Processes) model allows hydrograph simulation for the Liard and its sub‐basins. Three sets of reanalysis temperature and precipitation data provide inputs to assess the sensitivity of model simulation. The spatial patterns of snowmelt, runoff and stream discharge for four water years were simulated. The SLURP model was found to be sensitive to a plausible range of input conditions as depicted by the three sets of reanalysis data. Despite differences in detail among the three sets of simulation results, several generalities emerged. A comparison of simulated snow cover with satellite data confirms that there are altitudinal delays in spring flow generation though latitude has no apparent influence. Runoff lags snowmelt while the catchment integrates flows of its tributaries, yet different combinations of winter snowfall and spring melt rates cause large interannual variations in snowmelt discharge. Streamflow measured and simulated at four stations along the main river permits an evaluation of runoff contribution from various sectors of the basin. The overall pattern of melt runoff generation and the modelling approach used in this investigation are applicable to other large mountainous basins in high latitudes. Copyright © 2006 John Wiley & Sons, Ltd.
Regional differences in response of flow in glacier‐fed Himalayan rivers to climatic warming
Authors: Rees H. Gwyn , Collins David N.
Published: June 2006

River flow from glacierized areas in the Himalaya is influenced both by intra‐annual variations in precipitation and energy availability, and by longer term changes in storage of water as glacier ice. High specific discharge from ice melt often dominates flow for considerable distances downstream, particularly where other sources of runoff are limited, providing a major water resource. Should Himalayan glaciers continue to retreat rapidly, water shortages might be widespread within a few decades. However, given the difference in climate between the drier western and monsoonal eastern ends of the region, future warming is unlikely to affect river flow uniformly throughout.

A simple temperature‐index‐based hydro‐glaciological model, in which glacier dimensions are allowed to decline through time, has been developed with a view to assessing, in data‐sparse areas, by how much and when climate warming will reduce Himalayan glacier dimensions and affect downstream river flows. Two glaciers having the same initial geometries were located (one each) in the headwaters of two identical nests of hypothetical catchments, representing contrasting climates in the west and east of the region. The hypothetical catchments were nested such that percentage ice cover declined with increasing basin area. Model parameters were validated against available but limited mass‐balance and river flow measurements. The model was applied for 150 years from an arbitrary start date (1990), first with standard‐period (1961–1990) climate data and then with application of a 0·06 °C year−1 transient climatic warming scenario.

Under this warming scenario, Himalayan rivers fed by large glaciers descending through considerable elevation range will respond in a broadly similar manner, except that summer snowfall in the east will suppress the rate of initial flow increase, delay peak discharge and postpone eventual disappearance of the ice. Impacts of declining glacier area on river flow will be greater in smaller and more highly glacierized basins in both the west and east, and in the west, where precipitation is scarce, for considerable distances downstream. Copyright © 2006 John Wiley & Sons, Ltd.
Influence of the calcination temperature on the Au/FeOx/Al2O3 catalyst
Authors: Wang Donghui , Hao Zhengping , Cheng Daiyun , Shi Xicheng
Published: June 2006

The effect of calcination temperature on the electronic structure of gold catalyst was investigated in this paper. CO oxidation was employed as a test reaction to correlate the phase changes to the catalytic activity. The TPR, XPS and XRD characterization showed that the highly active Au/FeOx/Al2O3 catalyst contained both gold atoms and ions. The catalytic performance of gold catalyst may depend on the Au0/Au3+ ratio. The best activity in the present work was obtained when the Au0/Au3+ ratio was about 0.89. Copyright © 2006 Society of Chemical Industry
Preparation and evaluation of a novel chiral stationary phase based on covalently bonded chitosan for ligand‐exchange chromatography
Authors: Liu Yueqi , Zou Hanfa , Haginaka Jun
Published: June 2006

A novel chiral stationary phase based on chitosan covalently bonded onto silica gels has been prepared and used for the separation of various α‐amino acid enantiomers as well as α‐hydroxycarboxylic acid enantiomers by chiral ligand‐exchange chromatography with copper(II) as a complexing ion. The methanol content and copper(II) ion concentration in the eluent affected retentivity and enantioselectivity. Furthermore, a plausible chiral recognition mechanism for resolution of α‐amino acids was proposed.
Optimisation of the derivatization in cellulose‐type chiral selectors for enantioseparation by centrifugal partition chromatography
Authors: Pérez Eva , Minguillón Cristina
Published: June 2006

Cellulose was chemically modified with hydrophobic dodecanoyl groups followed by 3,5‐dimethylphenylcarbamoyl substituents forming mixed ester/carbamate derivatives in order to improve the solubility in lipophilic solvents compared to the corresponding homosubstituted cellulose tris(3,5‐dimethylphenylcarbamate). Two mixed derivatives of different degree of substitution were prepared, tested as chiral selectors (CSs) in counter‐current chromatography (CCC) and compared to the homo‐substituted derivative. Alternatively, cellulose tris(3,5‐dichlorophenylcarbamate), was synthesised and tested with the same purpose. The racemic drugs pindolol and warfarin were used as test compounds. Biphasic organic/aqueous solvent systems, composed of methyl isobutyl ketone, t‐butyl methyl ether or ethyl acetate and aqueous ammonium acetate or sodium phosphate buffer, were used. Centrifugal partition chromatography, a variety of CCC, in the classical elution mode and the pH‐zone‐refining displacement mode was applied. The enantioseparation of pindolol and warfarin was achieved in the latter conditions. The presence of dodecanoyl chains on the CS increased solubility in the organic solvents used. The selectivity of the mixed dodecanoyl/3,5‐dimethylphenylcarbamoyl cellulose derivative with low degree of dodecanoyl groups (degree of substitution 0.3/degree of substitution 2.6, respectively) was similar to that of the homo‐substituted derivative. Furthermore, the loading capacity for pindolol was increased by a factor of three compared to cellulose tris(3,5‐dimethylphenylcarbamate). Nevertheless, the increasing degree of substitution with dodecanoyl groups on the CS, although improved solubility in the stationary phase, contributed negatively to the enantioselectivity, where warfarin was more affected than pindolol.
Comprehensive processing, display and analysis for in vivo MR spectroscopic imaging
Authors: Maudsley A. A. , Darkazanli A. , Alger J. R. , Hall L. O. , Schuff N. , Studholme C. , Yu Y. , Ebel A. , Frew A. , Goldgof D. , Gu Y. , Pagare R. , Rousseau F. , Sivasankaran K. , Soher B. J. , Weber P. , Young K. , Zhu X.
Published: June 2006

Image reconstruction for magnetic resonance spectroscopic imaging (MRSI) requires specialized spatial and spectral data processing methods and benefits from the use of several sources of prior information that are not commonly available, including MRI‐derived tissue segmentation, morphological analysis and spectral characteristics of the observed metabolites. In addition, incorporating information obtained from MRI data can enhance the display of low‐resolution metabolite images and multiparametric and regional statistical analysis methods can improve detection of altered metabolite distributions. As a result, full MRSI processing and analysis can involve multiple processing steps and several different data types. In this paper, a processing environment is described that integrates and automates these data processing and analysis functions for imaging of proton metabolite distributions in the normal human brain. The capabilities include normalization of metabolite signal intensities and transformation into a common spatial reference frame, thereby allowing the formation of a database of MR‐measured human metabolite values as a function of acquisition, spatial and subject parameters. This development is carried out under the MIDAS project (Metabolite Imaging and Data Analysis System), which provides an integrated set of MRI and MRSI processing functions. It is anticipated that further development and distribution of these capabilities will facilitate more widespread use of MRSI for diagnostic imaging, encourage the development of standardized MRSI acquisition, processing and analysis methods and enable improved mapping of metabolite distributions in the human brain. Copyright © 2006 John Wiley & Sons, Ltd.
Single‐voxel 1H PRESS at 4.0 T: precision and variability of measurements in anterior cingulate and hippocampus
Authors: Venkatraman Talaignair N. , Hamer Robert M. , Perkins Diana O. , Song Allen W. , Lieberman Jeffrey A. , Steen R. Grant
Published: June 2006

The precision [coefficient of variation or CV (%) = 100SD/X] of single‐voxel point resolved spectroscopic data was characterized bilaterally, in anterior cingulate and in hippocampus, at 4.0 T in a healthy subject. Data acquisition was replicated 10 times after voxel repositioning and readjusting higher order shims. Precision measurements show that the scan‐to‐scan precision is better in anterior cingulate than in hippocampus, with an average CV of 9.2% (for total NAA, tCho and Cr) in anterior cingulate and 13.9% in hippocampus. Variability measurements made by the same method in 24 healthy subjects and in 29 schizophrenia patients showed that there is substantial biological variability in metabolite levels, even in healthy subjects. Simple calculations suggest that more than 200 subjects would be needed to detect a 5% difference in NAA between patients and controls. Copyright © 2006 John Wiley & Sons, Ltd.
YASSPP: Better kernels and coding schemes lead to improvements in protein secondary structure prediction
Authors: Karypis George
Published: June 2006

The accurate prediction of a protein's secondary structure plays an increasingly critical role in predicting its function and tertiary structure, as it is utilized by many of the current state‐of‐the‐art methods for remote homology, fold recognition, and ab initio structure prediction. We developed a new secondary structure prediction algorithm called YASSPP, which uses a pair of cascaded models constructed from two sets of binary SVM‐based models. YASSPP uses an input coding scheme that combines both position‐specific and nonposition‐specific information, utilizes a kernel function designed to capture the sequence conservation signals around the local window of each residue, and constructs a second‐level model by incorporating both the three‐state predictions produced by the first‐level model and information about the original sequence. Experiments on three standard datasets (RS126, CB513, and EVA common subset 4) show that YASSPP is capable of producing the highest Q3 and SOV scores than that achieved by existing widely used schemes such as PSIPRED, SSPro 4.0, SAM‐T99sec, as well as previously developed SVM‐based schemes. On the EVA dataset it achieves a Q3 and SOV score of 79.34 and 78.65%, which are considerably higher than the best reported scores of 77.64 and 76.05%, respectively. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Morphological and growth alterations in Vero cells transformed by cisplatin
Authors: Gonçalves Estela Maria , Ventura Cláudio Ângelo , Yano Tomomasa , Macedo Maria Lígia Rodrigues , Genari Selma Candelária
Published: June 2006

Cisplatin is an antineoplastic agent used to treat solid tumours, such as ovarian, testicular and bladder tumours. However, studies in vitro and in vivo have shown that cisplatin is mutagenic, genotoxic and tumorigenic in other tissues and organs. In this work, we examined the effect of cisplatin on Vero cells, a fibroblast‐like cell line. The morphological characteristics were investigated using phase contrast microscopy, scanning electron microscopy and the actin cytoskeleton was labelled with fluorescein isothiocyanate‐phalloidin. Cell proliferation was assessed based on the growth curve. Cultured Vero cells treated with cisplatin showed behavioural and morphological alterations associated with cellular transformation. The transformed cells grew in multilayers and formed cellular aggregates. The proliferation and morphological characteristics of the transformed cells were very different from those of control ones. Since transformed Vero cells showed several characteristics related to neoplastic growth, these cells could be a useful model for studying tumour cells in vitro.
How former communist countries of Europe may attract inward foreign direct investment? A matter of institutions
Authors: Fabry Nathalie , Zeghni Sylvain
Published: June 2006

The aim of this paper is to emphasize the role of institutions to attract FDI in 11 former communist European Countries: eight new members of the European Union (Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia, and Slovenia) and three candidates to a future enlargement (Bulgaria, Croatia and Romania). In a first step we proceed to an analytical framework to understand the link between transition, institutions and FDI. In a second step we test an empirical model based on pooled data. The results of our empirical test confirm our expectation that FDI is sensitive to specific and local institutional arrangements.
Introduction
Authors: CANNY NICHOLAS
Published: June 2006

This Focus addresses the relationship between historians and the societies they serve, particularly since the later nineteenth century when, for the first time, historians began to define themselves as a distinct professional group. One of the conclusions that emerges from the four case studies pursued here is that the independence of judgement which professionalism implies, founders the moment it is perceived by a wider public that historians are no longer providing them with the moral guidance they expect from those who have studied their pasts. It is also shown that the challenges and responses did not prove identical in any two sets of circumstances. This introduction also makes reference to general challenges to which individual contributors do not necessarily refer, but which have impacted on the work and independence of all historians.

Historians, both now and in the past, have been aware that what they write is, of necessity, influenced by their personal circumstances as also by their political and social preferences. Perhaps out of recognition of this, some writers of history in all centuries, and possibly from every culture, have celebrated their ability to shape policy in the present by citing experiences from past times. Then, in the nineteenth century, as governments in the west established Public Record Offices, National Archives and National Libraries, it came to be accepted in that part of the world that historians were professionals who, having undertaken a prescribed course of training, were uniquely equipped to assess how politicians and diplomats in the past had conducted their business.
Morality and slavery
Authors: MORGAN PHILIP D.
Published: June 2006

‘Morality and slavery’ argues that, as much as detachment and dispassion govern standard historical practice, historians cannot escape making moral judgments. Precisely because slavery is a morally charged subject, its history has been especially prone to changing points of view, traceable, for example, in recent histories of the slave trade and the controversy over Olaudah Equiano's birthplace. Various polar extremes – the structural coerciveness of slavery versus the agency of slaves; the persistence of African ethnicities versus rapid creolization; the spread of slavery versus the rapid growth of anti-slavery in the early republic – are evident in historical interpretations, which necessarily involve complicated value judgments and serious moral ramifications. The essay concludes by suggesting that a measure of balance and fairness has been possible in the study of slavery. Through empathy, historians have been able to recover, in part at least, the hopes and fears, dreams and nightmares, notions of right and wrong among both slaves and masters in previous epochs.
Modeling hydrology and silicon‐carbon interactions in taiga and tundra biomes from a landscape perspective: Implications for global warming feedbacks
Authors: Smedberg Erik , Mörth Carl‐Magnus , Swaney Dennis P. , Humborg Christoph
Published: June 2006

We used a simple hydrological‐biogeochemical mixing model to test the hypothesis that export of total organic carbon occurring mainly during spring in taiga and tundra watersheds might be compensated by production and export of bicarbonate (HCO3−) from groundwater during the rest of the year. The investigated watersheds are located in northern Sweden close to the Arctic Circle. An elevated spring flow peak due to snowmelt characterizes the hydrology of boreal and arctic river systems. During this snowmelt, total organic carbon (TOC), previously stored as soil carbon, is flushed and exported from the watersheds, and can be released to the atmosphere via heterotrophic remineralization during riverine transport to the sea, thereby contributing to atmospheric CO2. The TOC yields of the watersheds investigated increased with vegetation and peat cover and ranged across watersheds from 0.5 to 2.8 tons km−2 yr−1. During frozen periods, streamflow is dominated by “old” groundwater. This water has percolated through the soils and is rich in DSi and bicarbonate; that is, atmospheric carbon that has been “consumed” in chemical weathering processes is partly exported as bicarbonate to the sea, where carbon is stored as CaCO3 for geological time. The bicarbonate export of the watersheds investigated was between 0.4 and 1.2 tons C km−2 yr−1 corresponding to 15–73% of the TOC export. Very likely, global warming will affect water flow through the soils in taiga and tundra ecosystems and thus will have an effect on watershed carbon budgets. This bicarbonate export may compensate for significant amounts of the exported TOC, thereby reducing the positive feedback to atmospheric CO2.
Three‐dimensional forward and backward numerical modeling of mantle plume evolution: Effects of thermal diffusion
Authors: Ismail‐Zadeh Alik , Schubert Gerald , Tsepelev Igor , Korotkii Alexander
Published: June 2006

We investigate the effects of thermal diffusion on the evolution of mantle plumes by means of three‐dimensional numerical modeling forward and backward in time. Mantle plumes are fed by a hot, low‐viscous material from the thermal boundary layer. The material of the plumes is mainly advected toward the Earth's surface with some effects of thermal diffusion. However, the feeding can become weaker with time, and then thermal diffusion can take over and control the evolution of the plumes. Numerical experiments forward in time show that a week feeding of mantle plumes by the hot material from the boundary layer results in the diffusive disappearance of plume tails first and plume heads later. This is the most likely explanation for the seismically detected low‐velocity mantle structures (mantle plumes) with prominent heads and almost invisible tails at midmantle depths. We develop restoration models (backward in time) to recover strong features of mantle plumes in the geological past after they have dissipated due to thermal diffusion and analyze effects of thermal diffusion and temperature‐dependent viscosity on the reconstruction of the mantle plumes. We investigate the impact of thermal diffusion on the performance of our restoration (variational data assimilation) algorithm. For a given range of Rayleigh number Ra and two values of the viscosity ratio r (between the upper and lower boundaries of the model domain) we show that (1) the residuals between the temperature predicted by the forward model and that reconstructed by the backward modeling become larger and (2) the restoration process becomes poorer as Ra decreases and r increases. We assimilate temperature obtained from high‐resolution seismic tomography data for the southeastern Carpathians and show that present diffused mantle structures can be restored to their prominent state in the Miocene times. We discuss the problems of smoothness of model input and output data, errors associated with the modeling, and some other challenges in the data assimilation for thermoconvective flow in the mantle.
Pollutant-induced effects on immunological and physiological interactions in aquatic host–trematode systems: implications for parasite transmission
Authors: Morley N.J. , Lewis J.W. , Hoole D.
Published: June 2006

Under conditions of pollution both host and parasite are susceptible to the pathogenic effects of toxicants, which in turn may result in detrimental changes to their immunological and physiological processes. Digenetic trematodes, which encompass species of both medical and economic importance, possess complex life cycles and are common parasites of both vertebrates and molluscs. The combined stress induced by pollution and parasitism influences the physiology of the host which can have implications not only on host survival but also on the functional biology of resident parasite populations. The present paper reviews the effects of pollutants on the immunology and physiology in both vertebrate and molluscan host–trematode systems and the implications for parasite transmission.
How parasitism and pollution affect the physiological homeostasis of aquatic hosts
Authors: Sures B.
Published: June 2006

Parasitism poses a serious threat to hosts under certain circumstances, while the well-being of organisms is also negatively affected by environmental pollution. Little information is available on the simultaneous effects of parasites and pollutants on the physiological homeostasis of organisms. The present paper demonstrates that parasites: (i) may influence the metabolism of pollutants in infected hosts, (ii) interact with pollution in synergistic or antagonistic ways, and (iii) may induce physiological reactions in hosts which were thought to be pollutant-induced. Experimental studies on the uptake and accumulation of metals by fish reveal that fish infected with acanthocephalans have lower metal levels than uninfected hosts; e.g. Pomphorhynchus laevis reduces lead levels in fish bile, thereby diminishing or impeding the hepatic intestinal cycling of lead, which may reduce the quantity of metals available for fish. Alterations in pollutant uptake and accumulation in different intermediate and final hosts due to parasites are thus very important in the field of ecotoxicology. In addition to such alterations, there is a close interaction between the effects of pollutants and parasites which seems to be mediated at least partly by the endocrine system, which itself is closely related to the immune system in fish. Laboratory studies on eels experimentally infected with the swimbladder nematode Anguillicola crassus reveal that toxic chemicals such as polychlorinated biphenyls produce immunosuppressive effects which facilitate parasite infection. Similarly, an increase in serum cortisol concentration in eels due to chemical exposure and infection is correlated with decreasing levels of anti-A. crassus antibodies. Furthermore, parasites are able to elicit physiological changes which are attributed to chemicals with endocrine disrupting activity, e.g. the cestode Ligula intestinalis is known to suppress gonad development in roach. The most thoroughly documented examples of endocrine disruption in wild fish are in roach, and it is conceivable that this disruption is not only due to chemical activity but also to parasites such as L. intestinalis or species of the phylum Microspora.
Influence of climatic changes on the parasites of Atlantic cod Gadus morhua off coastal Labrador, Canada
Authors: Khan R.A. , Chandra C.V.
Published: June 2006

A study was conducted in 2000 and 2003, following the collapse of the commercial fishery in 1990, to compare metazoan parasites of Atlantic cod Gadus morhua, captured off coastal Labrador, with samples taken in 1980 and 1986. Fish were captured by otter trawl offshore in the North Atlantic Fish Organisation subarea 2J. Parasites were removed from the digestive tract, stained, identified and compared between the different groups. Both the prevalence and mean abundance of trematodes, larval nematodes and E. gadi were significantly lower in fish taken in 2000 and 2003 than in 1980. While mean values of trematodes and nematodes declined in 1986, those of Echinorhynchus gadi remained unchanged in 1986 and 1990. Four-year-old cod sampled in 1990 harboured significantly fewer E. gadi than older age groups. The most commonly occurring trematodes included Podocotylereflexa, Lepidapedon elongatum, Derogenes varicus and Hemiurus levinseni while the larval nematode, Anisakis sp. was predominant. Comparison of offshore samples taken in 2000 and 2003 with others taken in previous years suggests an overall decline of parasites coincident with a change in climatic conditions, the absence of a major food source, namely capelin Mallotus villosus, of cod and ultimately the decline of the Labrador population.
The swimbladder nematode Anguillicola crassus in the European eel Anguilla anguilla and the Japanese eel Anguilla japonica: differences in susceptibility and immunity between a recently colonized host and the original host
Authors: Knopf K.
Published: June 2006

The swimbladder nematode Anguillicola crassus originates from Asia where it is a parasite of the Japanese eel Anguilla japonica. After its introduction to Europe about 25 years ago, the parasite spread rapidly within the indigenous populations of the European eel Anguilla anguilla and subsequently the prevalence and mean intensity appeared to stabilize. Under experimental and aquaculture conditions the naïve new host appears to be more susceptible to A. crassus compared to the original host. Both eel species develop a immune response against A. crassus. The antibody response is well characterized for the European eel, but poorly characterized for the Japanese eel. It remains unclear if antibodies have any protective function against A. crassus. Encapsulation of larvae of A. crassus can be observed in naturally infected European eels. However, encapsulation of larvae following experimental infection has not been detected in European eels, but only in Japanese eels. Reinfection experiments and intraperitoneal injection of A. crassus homogenates failed to demonstrate the development of acquired immunity in European eels. Immunization with irradiated third stage larvae provided preliminary evidence for acquired immunity against A. crassus in the Japanese eel, but not in the European eel.
Making silicon hydrophobic: wettability control by two-lengthscale simultaneous patterning with femtosecond laser irradiation
Authors: Zorba V , Persano L , Pisignano D , Athanassiou A , Stratakis E , Cingolani R , Tzanetakis P , Fotakis C
Published: June 2006

We report on the wettability properties of silicon surfaces, simultaneously structured on the micrometre-scale and the nanometre-scale by femtosecond (fs) laser irradiation to render silicon hydrophobic. By varying the laser fluence, it was possible to control the wetting properties of a silicon surface through a systematic and reproducible variation of the surface roughness. In particular, the silicon–water contact angle could be increased from 66° to more than 130°. Such behaviour is described by incomplete liquid penetration within the silicon features, still leaving partially trapped air inside. We also show how controllable design and tailoring of the surface microstructures by wettability gradients can drive the motion of the drop’s centre of mass towards a desired direction (even upwards).
Arf6-independent GPI-anchored Protein-enriched Early Endosomal Compartments Fuse with Sorting Endosomes via a Rab5/Phosphatidylinositol-3′-Kinase–dependent Machinery
Authors: Kalia Manjula , Kumari Sudha , Chadda Rahul , Hill Michelle M. , Parton Robert G. , Mayor Satyajit
Published: June 2006

In the process of internalization of molecules from the extracellular milieu, a cell uses multiple endocytic pathways, consequently generating different endocytic vesicles. These primary endocytic vesicles are targeted to specific destinations inside the cell. Here, we show that GPI-anchored proteins are internalized by an Arf6-independent mechanism into GPI-anchored protein-enriched early endosomal compartments (GEECs). Internalized GPI-anchored proteins and the fluid phase are first visualized in GEECs that are acidic, primary endocytic structures, negative for early endosomal markers, Rab4, Rab5, and early endosome antigen (EEA)1. They subsequently acquire Rab5 and EEA1 before homotypic fusion with other GEECs, and heterotypic fusion with endosomes containing cargo from the clathrin-dependent endocytic pathway. Although, the formation of GEECs is unaffected by inhibition of Rab5 GTPase and phosphatidylinositol-3′-kinase (PI3K) activity, their fusion with sorting endosomes is dependent on both activities. Overexpression of Rab5 reverts PI3K inhibition of fusion, providing evidence that Rab5 effectors play important roles in heterotypic fusion between the dynamin-independent GEECs and clathrin- and dynamin-dependent sorting endosomes.
A Cluster of Ring Stage–specific Genes Linked to a Locus Implicated in Cytoadherence inPlasmodium falciparumCodes for PEXEL-negative and PEXEL-positive Proteins Exported into the Host Cell
Authors: Spielmann Tobias , Hawthorne Paula L. , Dixon Matthew W.A. , Hannemann Mandy , Klotz Kathleen , Kemp David J. , Klonis Nectarios , Tilley Leann , Trenholme Katharine R. , Gardiner Donald L.
Published: June 2006

Blood stages of Plasmodium falciparum export proteins into their erythrocyte host, thereby inducing extensive host cell modifications that become apparent after the first half of the asexual development cycle (ring stage). This is responsible for a major part of parasite virulence. Export of many parasite proteins depends on a sequence motif termed Plasmodium export element (PEXEL) or vacuolar transport signal (VTS). This motif has allowed the prediction of the Plasmodium exportome. Using published genome sequence, we redetermined the boundaries of a previously studied region linked to P. falciparum virulence, reducing the number of candidate genes in this region to 13. Among these, we identified a cluster of four ring stage-specific genes, one of which is known to encode an exported protein. We demonstrate that all four genes code for proteins exported into the host cell, although only two genes contain an obvious PEXEL/VTS motif. We propose that the systematic analysis of ring stage-specific genes will reveal a cohort of exported proteins not present in the currently predicted exportome. Moreover, this provides further evidence that host cell remodeling is a major task of this developmental stage. Biochemical and photobleaching studies using these proteins reveal new properties of the parasite-induced membrane compartments in the host cell. This has important implications for the biogenesis and connectivity of these structures.
Species traits and the form of individual species–energy relationships
Authors: Evans Karl L , Jackson Sarah F , Greenwood Jeremy J.D , Gaston Kevin J
Published: June 2006

Environmental energy availability explains much of the spatial variation in species richness at regional scales. While numerous mechanisms that may drive such total species–energy relationships have been identified, knowledge of their relative contributions is scant. Here, we adopt a novel approach to identify these drivers that exploits the composite nature of species richness, i.e. its summation from individual species distributions. We construct individual species–energy relationships (ISERs) for each species in the British breeding avifauna using both solar (temperature) and productive energy metrics (normalized difference vegetation index) as measures of environmental energy availability. We use the slopes of these relationships and the resultant change in deviance, relative to a null model, as measures of their strength and use them as response variables in multiple regressions that use ecological traits as predictors. The commonest species exhibit the strongest ISERs, which is counter to the prediction derived from the more individuals hypothesis. There is no evidence that predatory species have stronger ISERs, which is incompatible with the suggestion that high levels of energy availability increase the length of the food chain allowing larger numbers of predators to exist. We find some evidence that species with narrow niche breadths have stronger ISERs, thus providing one of the few pieces of supportive evidence that high-energy availability promotes species richness by increasing the occurrence of specialist species that use a narrow range of resources.
Numerical modelling and data assimilation of the Larsen B ice shelf, Antarctic Peninsula
Authors: Vieli Andreas , Payne Antony J , Du Zhijun , Shepherd Andrew
Published: June 2006

In this study, the flow and rheology of pre-collapse Larsen B ice shelf are investigated by using a combination of flow modelling and data assimilation. Observed shelf velocities from satellite interferometry are used to constrain an ice shelf model by using a data assimilation technique based on the control method. In particular, the ice rheology field and the velocities at the inland shelf boundary are simultaneously optimized to get a modelled flow and stress field that is consistent with the observed flow. The application to the Larsen B ice shelf shows that a strong weakening of the ice in the shear zones, mostly along the margins, is necessary to fit the observed shelf flow. This pattern of bands with weak ice is a very robust feature of the inversion, whereas the ice rheology within the main shelf body is found to be not well constrained. This suggests that these weak zones play a major role in the control of the flow of the Larsen B ice shelf and may be the key to understanding the observed pre-collapse thinning and acceleration of Larsen B. Regarding the sensitivity of the stress field to rheology, the consistency of the model with the observed flow seems crucial for any further analysis such as the application of fracture mechanics or perturbation model experiments.
The pubertal timing controversy in the USA, and a review of possible causative factors for the advance in timing of onset of puberty
Authors: Slyper Arnold H.
Published: June 2006

Previously used standards for the diagnosis of precocious puberty in girls no longer appear to be appropriate in the USA, in that a significant number of girls are being seen in paediatricians’ offices with breast budding before 8 years of age. The timing of menarche, however, has changed little over the past few decades. Early maturing girls are more likely to become obese in adolescence and adulthood than normal or late maturing girls. Early maturing white girls are heavier at the onset of puberty, but this is not the case for African‐American girls or boys of either race. Boys and girls with premature pubarche may be more hyperinsulinaemic than normal children, and girls with premature pubarche more likely to develop functional ovarian and adrenal hyperandrogenism. Early menarche is preceded by prepubertal hyperinsulinaemia. It is proposed that pubertal onset, although not necessarily the tempo of puberty, is influenced by hyperinsulinaemia and insulin resistance. If this hypothesis is correct, insulin resistance may be more prevalent in US children than previously recognized. An advance in timing of onset of puberty has not been noted in other countries, although it is likely that this phenomenon may become more prevalent as other countries adopt a more American lifestyle and diet.
Interactions between cottonwood and beavers positively affect sawfly abundance
Authors: BAILEY JOSEPH K. , WHITHAM THOMAS G.
Published: June 2006

Abstract 1. Cottonwood (Populus spp.) are the dominant tree type in riparian forests of the western U.S.A. In these riparian forests, the beaver (Castor canadensis) is a major ecosystem engineer that commonly browses cottonwood, resulting in distinct changes to plant architecture. Here the hypothesis that beaver herbivory indirectly affects the distribution of a keystone leaf‐galling sawfly through architectural changes in cottonwood was examined.

2. It was found that: (a) beaver herbivory of cottonwood results in an increase in average shoot length over unbrowsed cottonwood; (b) sawfly galls were up to 7–14 times more abundant on browsed cottonwood than unbrowsed cottonwood; and (c) sawfly gall abundance was correlated positively with changes in shoot length after beaver herbivory. Together these data show that the individual and combined effects of cottonwood and beaver herbivory increase shoot length, positively affecting sawfly abundance.

3. Because herbivores are a ubiquitous component of most ecosystems, we argue that the indirect effects of herbivory on plant quality, and subsequently other herbivores, may be as important as environmental variation.
The influence of temperature on migration of Lepidoptera into Britain
Authors: Sparks T. H. , Roy D. B. , Dennis R. L. H.
Published: June 2006

A unique 113‐year record of numbers of nine migrating butterflies and 20 migrating moths is examined in relation to temperatures on the migration route, to temperatures in England, and to the North Atlantic oscillation (NAO). This study clearly reveals the strong association between numbers of migrant Lepidoptera and temperatures in France; with higher temperatures associated with increased migrant numbers. The NAO also appears influential with high index years associated with increased numbers. The strong temperature link suggests that Britain and other northern temperate countries can expect to receive larger numbers of migrant Lepidoptera if climate warms as predicted in the 21st century.
Contrasting responses to drought of forest floor CO2 efflux in a Loblolly pine plantation and a nearby Oak‐Hickory forest
Authors: Palmroth S. , Maier C. A. , McCarthy H. R. , Oishi A. C. , Kim H.‐S. , Johnsen K.H. , Katul G. G. , Oren R.
Published: June 2006

Forest floor CO2 efflux (Fff) depends on vegetation type, climate, and soil physical properties. We assessed the effects of biological factors on Fff by comparing a maturing pine plantation (PP) and a nearby mature Oak‐Hickory‐type hardwood forest (HW). Fff was measured continuously with soil chambers connected to an IRGA during 2001–2002. At both sites, Fff depended on soil temperature at 5 cm (T5) when soil was moist (soil moisture, θ>0.20 m3 m−3), and on both T5 and θ when soil was drier. A model (Fff (T5, θ)) explained 92% of the variation in the daily mean Fff at both sites. Higher radiation reaching the ground during the leafless period, and a thinner litter layer because of faster decomposition, probably caused higher soil temperature at HW compared with PP. The annual Fff was estimated at 1330 and 1464 g C m−2 yr−1 for a year with mild drought (2001) at PP and HW, respectively, and 1231 and 1557 g C m−2 yr−1 for a year with severe drought (2002). In the wetter year, higher soil temperature and moisture at HW compared with PP compensated for the negative effect on Fff of the response to these variables resulting in similar annual Fff at both stands. In the drier year, however, the response to soil temperature and moisture was more similar at the two stands causing the difference in the state variables to impel a higher Fff at HW. A simple mass balance indicated that in the wetter year, C in the litter–soil system was at steady state at HW, and was accruing at PP. However, HW was probably losing C from the mineral soil during the severe drought year of 2002, while PP was accumulating C at a lower rate because of a loss of C from the litter layer. Such contrasting behavior of two forest types in close proximity might frustrate attempts to estimate regional carbon (C) fluxes and net C exchange.
Epicutaneous immunization converts subsequent and established antigen‐specific T helper type 1 (Th1) to Th2‐type responses
Authors: Strid Jessica , Callard Robin , Strobel Stephan
Published: June 2006

Epicutaneous immunization is a potential novel technique for topical vaccine delivery. It targets the immunologically rich milieu of the skin while having the advantage of being a non‐invasive immunization procedure. By disrupting the stratum corneum of the epidermis a natural adjuvant effect can be achieved through activation of resident Langerhans cells. This negates the normal need for co‐application of noxious adjuvants. Epicutaneous immunization on barrier‐disrupted skin induces potent antigen‐specific systemic immunity with a strong T helper type 2 (Th2) bias. We show here that epicutaneous immunization enhances the vigour of a subsequent T‐cell response to the same antigen. The induced systemic Th2 response prevents the development of Th1 responses induced through injection of antigen in complete Freund's adjuvant (CFA). Prior epicutaneous immunization results in reduced production of antigen‐specific interferon‐γ and immunoglobulin G2a (IgG2a) and enhanced interleukin‐4, IgG1 and IgE responses to immunization with CFA. Moreover, epicutaneous immunization converts an established Th1 response to a Th2 response, as demonstrated by the specific reduction of interferon‐γ and IgG2a and the enhancement of interleukin‐4 and IgE. This Th2 dominance of epicutaneous immunization may have direct therapeutic application as an immune‐modulating procedure in Th1‐dominant diseases such as autoimmune rheumatoid arthritis, type 1 diabetes, Hashimoto's thyroiditis and multiple sclerosis.