bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of a semi-empirical emissivity model for a rough estimation of sea surface salinity from an airborne microwave radiometer
Authors: Gabarró Carolina , Font Jordi , Miller Jerry , Camps Adriano , Burrage Derek , Wesson Joe , Piola Alberto R.
Published: October 2008

In preparation for the European Space Agency SMOS (Soil Moisture and Ocean Salinity) satellite mission, radiometric and oceanographic measurements were performed in December 2000 and January 2001 and in November 2001 from a fixed platform in the NW Mediterranean to improve the modelling of the sea surface emissivity at L-band and new semi-empirical models were derived. Now one of these models has been used to retrieve sea surface salinity from L-band radiometric data acquired with a different instrument and different location. These data were acquired in August 2003 over the continental shelf within the influence of the Rio de la Plata, from Argentina to Brazil, southern Atlantic ocean with the STARRS airborne radiometer. Results show that the radiometer is capable of realistically detecting natural variations in surface salinity even though the model was derived in very different oceanographic conditions and from data collected by a different instrument.
On some frenulate species (Annelida: Polychaeta: Siboglinidae) from mud volcanoes in the Gulf of Cadiz (NE Atlantic)
Authors: Hilário Ana , Cunha Marina R.
Published: October 2008

Collections of Frenulata made by the RV Professor Logachev in the Gulf of Cadiz in 2006 contain two new species, one belonging to the genus Spirobrachia, and another that was assigned to a new genus. Spirobrachia tripeira n. sp. is the first record of the genus in the North Atlantic Ocean; it has a very stiff, straight, orange tube; its tentacles have pinnules and are arranged in a spiral crown without a lophophore. Bobmarleya gadensis n. gen. et n. sp. is characterised by an unusually long tentacular crown composed of about 40 free tentacles. It shares many characteristics with the genus Oligobrachia but the large number and extreme length of the tentacles and a combination of other characters justify the designation of a new genus. The specimens of Lamellisabella denticulata Southward, 1978 collected during the M.S. Merian 03/01 cruise provide the first record of this species in the Gulf of Cadiz.
Reproduction and spawning habitat of white trevally, Pseudocaranx dentex, in the Azores, central north Atlantic
Authors: Afonso Pedro , Fontes Jorge , Morato Telmo , Holland Kim N. , Santos Ricardo S.
Published: October 2008

Reproductive biology and habitat preferences of the white trevally, Pseudocaranx dentex (Carangidae), were studied in the Azores islands, central north Atlantic, to determine the spatial and seasonal dynamics of habitat use of immature and mature fish. The sex ratio was close to 1:1 and fish matured at about 30 cm fork length. There were no differences in the maturation or length-weight relationships between sexes. The spawning season lasts from June to September. Underwater visual censuses showed that schools of mature individuals preferentially aggregate around the summits of offshore reefs during the spawning season. In contrast, schools of smaller, immature fish use inshore habitats all year round. Our data support the hypothesis that offshore reefs are a preferential spawning habitat of larger white trevally, and most possibly for a number of visitor pelagic predators as well. Inverse relationships between exploitation levels, abundance and size composition at the two different islands suggest that the summer fishery targeting trevally schools around offshore reefs has negatively impacted the population. These findings bring additional ecological and management relevance to offshore reefs.
The genus Branchiomma (Polychaeta: Sabellidae) in the Mediterranean Sea, with the description of B. maerli n. sp.
Authors: Licciano Margherita , Giangrande Adriana
Published: October 2008

The genus Branchiomma (Annelida: Polychaeta: Sabellinae) from the Mediterranean Sea is revised based on material collected during several surveys and preserved in the Zoological Laboratory of Lecce University (South Italy). Branchiomma maerli n. sp. is described as a new species and compared with the previously reported B. bombyx, B. lucullanum, B. luctuosum, and B. cf. moebii. Branchiomma maerli n. sp. resembles B. lucullanum, but differs in the shape of the collar and in the length of the dorsal lips. Branchiomma boholensis, reported as the only Mediterranean species with macrostylodes, is not here described because it has not been possible to obtain adequate material. Finally, Branchiomma sp. (similar to B. violaceum, but having the dorsal collar fused to the faecal groove) is not formally described as a new species because there is only one available specimen.
The feeding ecology of Aphanius fasciatus (Valenciennes, 1821) in the lagoonal system of Messolongi (western Greece)
Authors: Leonardos Ioannis
Published: October 2008

The Mediterranean toothcarp Aphanius fasciatus (Valenciennes, 1821) is a small-sized omnivorous estuarine fish. Its diet is dominated by juveniles of shrimps (Palaemon adspersus), Isopods, Branchiopoda, Bivalvia, eggs of invertebrates, mosquitoes (adults and larvae) and diatoms. An ontogenetic diet shift with an increase in mean prey size with fish length was observed. Smaller fish feed on planktonic prey (e.g. copepods, ostracods, nauplii of Artemia), while larger fish prefer larger and more benthic preys (e.g. ampipods, Bivalvia). The diet of A. fasciatus shows a high degree of seasonal variation, with a reduction in the feeding activity during the periods of adverse environmental conditions (winter and autumn). It is a well-adapted estuarine fish, its feeding mode and preferences depending on the preys that are available. Its feeding strategy is characterised by specialisation in different resource types (aquatic invertebrates and mosquitoes) and a high between-phenotype contribution (BPC) to niche width, with specialised individuals showing little or no overlap in resource use.
Sperm ultra-structure of Odontosyllis ctenostoma (Polychaeta: Syllidae) with inferences on syllid phylogeny and reproductive biology
Authors: Giangrande Adriana , Gherardi Miriam , Lepore Elena , Mercurio Maria , Sciscioli Margherita
Published: October 2008

The analysis of the complex reproductive patterns of Syllidae may drastically change the taxonomic hierarchy of the family. To further contribute to the knowledge of Syllidae we have described the sperm ultra-structure and some steps of spermiogenesis of Odontosyllis ctenostoma Claparède, 1868, the first non interstitial eusylline investigated. The mature sperm has a bell-shaped acrosome and contains electron-dense granular material and thin filaments. The barrel-shaped nucleus bears two depressions: one anterior facing the acrosome and the other posterior partially containing the distal centriole and up to six mitochondria. Odontosyllis ctenostoma spermatozoa can be ascribed to the ect-aquasperm type typical of species practising external fertilisation. This morphology is not in complete accordance either with the particular brood protection reported for the species or the egg size. The sperm is similar to those of the Syllinae species thus far investigated, but the acrosome resembles that of the exogonine spermatid. Some authors consider Odontosyllis to be phylogenetically closer to Syllinae, though it shares epigamy with Exogoninae. Others have hypothesised that the exogonine sperm could have been derived from sylline sperm by simplification. In our hypothesis this could have happened through a gradual passage from an Odontosyllis-like eusylline ancestor.
Site-attachment behaviour of Oblada melanura (Linnaeus, 1758) (Osteichthyes: Sparidae) benthic larvae: a quantitative approach
Authors: Kiparissis Sotiris , Tserpes George , Somarakis Stylianos , Economidis Panos S. , Koutsikopoulos Constantin
Published: October 2008

The site-attachment behaviour of O. melanura settlers was examined in an estuarine area of western Greece. The approach that was followed included underwater assignments of shoal identities and continuous recording of specific behavioural traits. Variations between ontogenetic stages with respect to the pattern of residence at the sites were quantified via an index (the residence-persistence index (RPI)) devised for this purpose. Our findings suggest that this species initiates settlement in small shoals that occupy specific sites at the substratum where they reside for various days. This behavioural trait is stage-specific and gradually diminishes as the fish complete metamorphosis, while at the same time they change their social organisation. Such an ontogeny-dependent site-attachment behaviour has not been described before and is markedly different from that described for other members of the Sparidae family.
Mitochondrial DNA reveals regional and interregional importance of the central Mediterranean African shelf for loggerhead sea turtles (Caretta caretta)
Authors: Casale Paolo , Freggi Daniela , Gratton Paolo , Argano Roberto , Oliverio Marco
Published: October 2008

The wide north African continental shelf in the central Mediterranean is known to be one of the few important areas in the basin for loggerhead turtles in the neritic stage. In order to assess the origin of these turtles, sequences of the mtDNA control region were obtained from 70 turtles caught by bottom trawlers in the area, and compared with known sequences from turtles from Mediterranean and Atlantic nesting sites. Five haplotypes were identified (Haplotype diversity = 0.262; nucleotide diversity = 5.4×10-3). Specific haplotypes indicate contributions from distant rookeries such as Turkey and the Atlantic, which shows that Atlantic turtles entering the Mediterranean while in the oceanic phase use at least one Mediterranean continental shelf as a neritic foraging ground. A new haplotype and another one previously found only in foraging areas, highlight the genetic information gaps for nesting sites, which undermine powerful mixed stock analyses. Despite these limitations, the results reveal the regional importance of the study area as a neritic foraging ground for turtles that are probably from most of the Mediterranean nesting aggregates. Therefore, reducing turtle mortality resulting from the high fishing effort in the area should be regarded as key for Mediterranean turtle conservation and is also possibly important for Atlantic populations.
Spatial and temporal patterns in size and maturation of Loligo plei and Loligo sanpaulensis (Cephalopoda: Loliginidae) in southeastern Brazilian waters, between 23°S and 27°S
Authors: Rodrigues Amanda R. , Gasalla Maria A.
Published: October 2008

Patterns of population dynamics of Loligo plei and Loligo sanpaulensis in southeastern Brazil were investigated with samples obtained from commercial catches and research cruises from 1999 to 2000 and from 2002 to 2003. Size and maturity structure of the two species varied according to depth and season. Body size decreased with depth for L. plei, whereas for L. sanpaulensis size increased with depth up to 100 m and decreased again in deeper areas. GSI and incidence of mature animals decreased with depth in both species. L. plei females matured at a larger size in summer, while size at maturity in L. sanpaulensis was greater in autumn. For L. plei, reproductive events occurred in the late winter and spring, in depths up to 40 m, and during summer in inshore waters. L. sanpaulensis increased reproductive activity in summer, winter and spring between depths of 30 and 80 m. The presence of high proportions of immature squid offshore suggests that juveniles might develop in these areas and, upon maturation, migrate back to inshore waters to spawn, particularly in spring and summer. However, differences found in aggregation patterns in different depth strata, as well as the seasonal differences found in the size structure of L. plei and L. sanpaulensis, could ultimately be due to changes in the water column related to food availability. Considering that L. plei and L. sanpaulensis are both caught as by-catch by shrimp trawlers throughout the year, we also discuss hypotheses on the life cycle of the species and its implications for fishery management. We recommend measures to protect squid spawning grounds by creating spring and summer protected areas where trawling would be prohibited until 60 m depth, i.e. in the area and time of year when mature individuals concentrate.
Differences in demersal community structure and biomass size spectra within and outside the Maltese Fishery Management Zone (FMZ)
Authors: Dimech Mark , Camilleri Mattew , Hiddink Jan G. , Kaiser Michel J. , Ragonese Sergio , Schembri Patrick J.
Published: October 2008

We examined the protection effect of a long-established fisheries protection zone by studying the demersal communities and the biomass size spectra of specific taxonomic groups. The results and the relevant management implications of the community analysis are discussed within the context of the MEDITS trawl survey program, from which the data was derived. The demersal fishery resources on the muddy bottoms of Maltese trawling grounds were found to be stratified in four main depth ranges: 83 to 166 m (outer continental shelf), 140 to 230 m (shelf break), 270 to 440 m (shallow slope), and 466 to 701 m (deep slope). Significant differences were detected between the inside and outside zones of the outer continental shelf. Stations from this stratum inside the protected zone had twice as much biomass as those outside as well as larger individuals of some species (e.g. elasmobranchs). The depth strata identified do not coincide with those sampled in existing trawl survey programmes in the Sicilian Channel, which were set up without reference to demersal assemblage structure and its relation to depth. It is therefore clear that characterisation of the biotic assemblages is important in order to obtain a better sampling representation of each depth-stratum/assemblage type, and this should be considered in the survey design.
Synthesized views can improve face recognition
Authors: Liu Chang Hong , Chai Xiujuan , Shan Shiguang , Honma Motoyasu , Osada Yoshihisa
Published: October 2008

It is well known that a new face studied from one view is often difficult to identify from another. This viewpoint dependence has detrimental implications for forensic practice. To compensate for this problem, we employed synthesized face images in the training session of a standard old/new recognition task. Observers in the experimental conditions learned one or more synthesized face images along with an original photograph of the face in a different view, whereas observers in the control conditions learned only the original photograph of the face. It was found that the experimental conditions consistently produced better recognition accuracy than the control conditions. We conclude that synthesized face views can be used to facilitate person identification in forensic applications. Copyright © 2008 John Wiley & Sons, Ltd.
Suboptimal filter for continuous‐time linear systems with unknown parameters
Authors: Kim Du Yong , Ahn Jun Il , Shin Vladimir
Published: October 2008

The filtering problem for continuous‐time linear systems with unknown parameters is considered. A new suboptimal filter is herein proposed. It is based on the optimal mean‐square linear combination of the local Kalman filters. In contrast to the optimal weights, the suboptimal weights do not depend on current observations; thus, the proposed filter can easily be implemented in real‐time. Examples demonstrate high accuracy and efficiency of the suboptimal filter. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Feedforward controller synthesis for linear time variant systems
Authors: Tarniceriu Daniela , Munteanu Valeriu
Published: October 2008

This paper develops a framework for the synthesis of a feedforward controller for both discrete and continuous linear time variant (LTV) systems. The proposed method determines the structure of a feedforward controller, which is cascaded with the known time varying process, so that the ensemble behaves as a linear time invariant (LTI) system, satisfying certain design requirements. The obtained controller is simple, consisting in a parallel bank of first or second order LTI filters, followed by amplifiers with time variable gain. Simulation results are included to illustrate theoretical considerations. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Robust H∞ controller design for continuous‐time piecewise time‐delay systems
Authors: Song Xinmin , Zhou Shaosheng , Zhang Huanshui , Zhao Hongguo
Published: October 2008

This paper investigates the robust H∞ control problem for continuous‐time piecewise time‐delay systems by using piecewise continuous Lyapunov function. The uncertainties of the systems under consideration are expressed in a linear fractional form. A strict linear matrix inequality approach is developed to obtain delay‐dependent asymptotic stability conditions and H∞ performance. The H∞ controller design problem is solved by exploiting the cone complementarity linearization (CCL) method. Finally an example is given to illustrate the application of the proposed approach. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Infinite horizon linear quadratic optimal control for discrete‐time stochastic systems
Authors: Huang Yulin , Zhang Weihai , Zhang Huanshui
Published: October 2008

This paper is concerned with the infinite horizon linear quadratic optimal control for discrete‐time stochastic systems with both state and control‐dependent noise. Under assumptions of stabilization and exact observability, it is shown that the optimal control law and optimal value exist, and the properties of the associated discrete generalized algebraic Riccati equation (GARE) are also discussed. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
New results on non‐fragileH∞controller design for uncertain linear systems
Authors: Zhang Baoyong , Xu Shengyuan , Zhou Shaosheng , Zong Guangdeng
Published: October 2008

This paper deals with the non‐fragileH∞control problem for uncertain linear systems. The uncertainties are of a linear fractional form and appear in both the state and control input matrices. The purpose is to design a state feedback controller, which is subject to linear fractional parametric uncertainties, such that the resulting closed‐loop system is quadratically stable with anH∞norm bound. A sufficient condition for the solvability of the problem is obtained in terms of linear matrix inequalities. A numerical example is provided to demonstrate the effectiveness of the proposed design method. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Developmental toxicity assessment of d,l‐Methylphenidate and d‐Methylphenidate in rats and rabbits
Authors: Beckman David A. , Schneider Marilynn , Youreneff Maureen , Tse Francis L.S.
Published: October 2008

BACKGROUND:Previous investigations reported no teratogenicity for methylphenidate (MPH). These studies investigated potential teratogenicity of d‐MPH and d,l‐MPH as commitments to the FDA.METHODS:Rabbits received 15, 50, 150 mg/kg/day (mkd) d‐MPH or 20, 60, 200, 300 mkd d,l‐MPH on gestation days 7–20. Rats received 2.5, 10, 40 mkd d‐MPH, or 7, 25, 75, 80 mkd d,l‐MPH on gestation days 6–17.RESULTS:d‐MPH—In rabbits, mortality occurred at 150 mkd. Dilated pupils, increased activity, biting/chewing, respiration, and salivation occurred at ≥15 mkd in rabbits and ≥10 mkd in rats. Decreased food consumption occurred at 40 mkd in rats. Decreased body weight parameters occurred at 150 mkd in rabbits and ≥10 mkd in rats. There were no fetal findings in rabbits. In rats, skeletal variations occurred at 40 mkd. d,l‐MPH—In rabbits, mortality occurred at ≥200 mkd. Dilated pupils, increased activity, biting/chewing, respiration, and salivation occurred at ≥20 mkd in rabbits and ≥25 mkd in rats. Decreased food consumption occurred at ≥200 mkd in rabbits and ≥25 mkd in rats. Decreased body weight parameters occurred at ≥200 mkd in rabbits and ≥25 mkd in rats. In rabbits, two fetuses (separate litters) had spina bifida and malrotated hindlimbs at 200 mkd. In rats, skeletal variations occurred at ≥75 mkd.CONCLUSIONS:There was no teratogenicity with d‐MPH. There was a low teratogenic risk with d,l‐MPH in only the rabbit. Higher Cmaxmay explain differences in results from previous studies.Birth Defects Res (Part B)83:489‐501, 2008. © 2008 Wiley‐Liss, Inc.
Ordovizium und Silur. Überschwemmungen, eine Eiszeit und die Eroberung des Festlandes
Authors: Rothe Peter
Published: October 2008

Ordovizium und Silur sind überwiegend durch dunkle, tonige Ablagerungen sauerstoffarmer Meere gekennzeichnet, denen flachmarine Sandbarren auf den Schelfen und kalkige Riffbereiche gegenüberstanden. Im pelagischen Bereich gab es eine Vielzahl von Graptolithenarten, die von anfangs noch sessiler zu planktonischer Lebensweise übergingen, was sie zu ausgezeichneten Leitfossilien macht. Auch Trilobiten und Brachiopoden erlebten eine stürmische Entwicklung. In Flachmeeren entstanden von Bryozoen und Korallen gebildete Riffe. Erste Sporenfunde im Ordovizium belegen die beginnende Besiedlung des Festlands durch Pflanzen, die im Silur schon bedeutend war. Am Ende des Ordoviziums kam es zu einem Massenaussterben, das wahrscheinlich durch einen Klimawandel gesteuert war, von dem auch eine ordovizische Eiszeit zeugt.
Horizontaler Gentransfer. DNA‐Austausch über Artgrenzen hinweg
Authors: Wilharm Gottfried
Published: October 2008

Mechanismen des horizontalen Gentransfers (HGT) sind im Bakterienreich und bei Archaeen weit verbreitet und prägen das Erscheinungsbild mancher mikrobieller Genome wesentlich. Da über HGT komplett neue Stoffwechselwege, Proteintransportapparate oder andere komplexe Funktionen in einem Schritt erworben werden können, können evolutive Quantensprünge über kurze Zeiträume erklärbar werden. Am Beispiel bakterieller Krankheitserreger wird die Bedeutung von HGT für Resistenzentwicklungen, Virulenzausprägung und Wirtsanpassung besonders deutlich. HGT‐Ereignisse haben im Laufe der Entwicklungsgeschichte der Lebewesen auch zwischen weit entfernten Entwicklungslinien immer wieder stattgefunden. Der zum Teil erhebliche HGT‐abhängige genetische Fluss über Artgrenzen hinweg macht eine neue Betrachtungsweise von Verwandtschaftsverhältnissen nötig.
Zelloberflächenlipide signalisieren Zelltod
Authors: Hille‐Rehfeld Annette
Published: October 2008

Die asymmetrische Lipidzusammensetzung der Plasmamembran ist für die Zelle lebenswichtig. Ändert sie sich, wie im Fall des programmierten Zelltods, so wird die absterbende Zelle von benachbarten Zellen als solche erkannt und durch Mikropinocytose eliminiert. Pockenviren nutzen diesen Mechanismus für die Infektion von Wirtszellen nach Art eines trojanischen Pferdes.
Blogs, Wikis und Podcasts im Unterricht
Authors: Fenner Martin
Published: October 2008

Mit dem im Jahr 2005 geprägten Begriff Web 2.0 ist eine veränderte Nutzung des Internets gemeint, bei der die Inhalte in zunehmendem Maße vom Nutzer selbst erstellt werden. Typische Beispiele sind Blogs und Wikis, die sich ebenso wie andere Web 2.0‐Anwendungen hervorragend zur Unterstützung des Unterrichts an Schulen und Universitäten eignen.
Nachrichten des Verbandes Biologie, Biowissenschaften amp; Biomedizin in Deutschland
Authors: Bickel Susanne
Published: October 2008

Wissenschaft und Gesellschaft:

Moderne Genetik jenseits von Erbsen und Fliegen

Aus den Fachgesellschaften:

Erklärung der Gesellschaft für Humangenetik

Materialien:

Neuer VBIO‐Flye

Aus den Landesverbänden:

Landesverband Berlin/Brandenburg

Landesverband Bayern
A novel low‐complexity transmission power adaptation in MC‐CDMA systems witha‐MRC receiver over Nakagami‐mfading channels
Authors: Feng Yizhi , Qin Jiayin , Wei Gang , Ji Fei
Published: October 2008

In this paper, we propose a novel low‐complexity transmission power adaptation with good bit error rate (BER) performance for multicarrier code‐division multiple‐access (MC‐CDMA) systems over Nakagami‐mfading channels. We first propose a new receiver calledath‐order‐maximal‐ratio‐combining (a‐MRC) receiver with which the receiver power gain for thenth subcarrier is theath (a⩾1) power of the corresponding channel gain. Incorporating thea‐MRC receiver, we then propose a new transmission power adaptation scheme where the transmission power is allocated over all theNsubcarriers according to the subchannel gains and the transmitter adapts its power to maintain a constant signal‐to‐interference‐plus‐noise (SINR) at the receiver. The proposed scheme has a significant performance gain over the nonadaptive transmission scheme over both independent and correlated fading channels. Moreover, the proposed scheme keeps good BER performance while it is much simpler than the previous power control/adaptation schemes. Copyright © 2008 John Wiley & Sons, Ltd.
A male‐specific effect of dominant‐negative Fos
Authors: Pierre Wooly , Morra Rosa , Lucchesi John , Yedvobnick Barry
Published: October 2008

The transcription factor Fos contains a basic DNA binding domain combined with a leucine zipper (bZip). Expression of a truncated form of Fos in Drosophila that contains only the bZip region (Fos bZip) elicits phenotypes resembling fos mutations. These effects presumably derive from competition between wild‐type and truncated forms for dimerization partners, with the truncation acting in a dominant‐negative manner. We found that expression of Fos bZip elicits male‐specific phenotypes. Moreover, genetic interactions occur between Fos bZip and mutations in loci encoding the X chromosome dosage compensation complex. Fos bZip effects are correlated with aberrant male X chromosome structure and depressed signaling through the X‐linked Notch locus. Unexpectedly, the male‐specific effects are not reproduced with Fos RNAi, suggesting that Fos bZip can be neomorphic in nature. These results provide insight into how mutations in bZip proteins can exhibit gain of function activity. Developmental Dynamics 237:3361–3372, 2008. © 2008 Wiley‐Liss, Inc.
Palladium‐Catalyzed Cyclization/Carbonylation as a Direct Route to 4‐[(Methoxycarbonyl)methyl]‐3,4‐dihydroisoquinolinones
Authors: Ardizzoia G. Attilio , Beccalli Egle M. , Borsini Elena , Brenna Stefano , Broggini Gianluigi , Rigamonti Micol
Published: October 2008

An efficient synthetic protocol for the preparation of4‐[(methoxycarbonyl)methyl]‐3,4‐dihydroisoquinolin‐1‐onesfrom N‐allylamides of 2‐iodobenzoic acids has been performed under 100 atm of carbon monoxide. Pyridine ring formation occurs through an intramolecular Pd‐catalyzed carbon–carbon bond formation, followed by an alkoxycarbonylation process.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Measurement of the differences in electrophoretic mobilities of individual molecules of E. coli β‐galactosidase provides insight into structural differences which underlie enzyme microheterogeneity
Authors: Nichols Ellert R. , Craig Douglas B.
Published: October 2008

The electrophoretic mobility and catalytic activity of individual molecules of Escherichia coli β‐galactosidase were measured using CE‐LIF detection. Both the mobility and activity were reproducible for each molecule but differed between individual molecules. Assays were performed using uncoated capillaries and capillaries coated with different polymers, using enzymes from different sources and by three different experimental protocols. In all cases the observed ranges in electrophoretic mobilities were similar. The observed range in the electrophoretic mobility may be explained by structural microheterogeneity resulting in a gain or loss of up to 1.6 suppressed charge units. There was no observed relationship between the observed activities and electrophoretic mobilities. If the finding that individual β‐galactosidase molecules have heterogeneous electrophoretic mobility can be extended to other proteins, this may limit the resolution possible for capillary zone electrophoresis protein separations.
Proteomic analysis of conditioned media from glucose responsive and glucose non‐responsive phenotypes reveals a panel of secreted proteins associated with beta cell dysfunction
Authors: Dowling Paul , Shields William , Rani Sweta , Meleady Paula , Henry Michael , Jeppesen Per , O'Driscoll Lorraine , Clynes Martin
Published: October 2008

Media conditioned by dysfunctioning pancreatic beta cells offer an excellent source of potential protein markers associated with this phenotype. Proteins identified from cell culture model systems are often found to be of importance clinically. Previous work by us and others have shown that low‐passage MIN‐6 cells (MIN‐6(L)) respond to changes in glucose concentrations, producing an approximately 5.5‐fold glucose‐stimulated insulin secretion (GSIS) in response to 26.7 mmol/L, compared with 3.3 mmol/L, glucose. After continuous culture or high‐passage (MIN‐(H)), this GSIS was no longer present and thus represents an excellent model system for investigating beta cell dysfunction. Employing 2‐D difference gel electrophoresis and mass spectrometry a panel of protein markers were identified in conditioned media (CM) from MIN‐6(L) and MIN‐6(H) beta cells. These proteins, including secretogranin II, secretogranin III and transthyretin, are associated with secretory granule biogenesis and were found to have substantially increased levels in the CM from the non‐responsive high‐passage MIN‐6 beta cells. A panel of protein markers found to have increased abundance levels in CM from MIN‐6(H) compared with MIN‐6(L) beta cells may have the potential to be used clinically for assessing beta cell function and to monitor the effects of specific therapeutics.
Spatial variability in precipitation within the Hilton Experimental Site, Shropshire, UK (1982–2006)
Authors: Subedi M. , Fullen M. A.
Published: October 2008

Accurate precipitation measurements are essential for many hydrological and hydrogeological management strategies. Precipitation at the Hilton Experimental Site has been regularly measured since 1982. This paper summarises 157 rain gauge years of precipitation data, recorded between 1982 and 2006, using 11 rain gauges on the 0·5 hectare site. Precipitation varied markedly within the site. Precipitation totals were notably different between two adjacent rain gauges, the mean difference being 0·3% of the total. Variations in mean annual precipitation within the site were ⩽8%. Spatial variations in wind turbulence appeared to be the main factor influencing intra‐site variability. Precipitation totals varied with gauge exposure, with surface level gauges receiving ⩽5·9% more precipitation than standard rain gauges, the difference being less lower down the slope. On a steep (∼15° ) slope, basal sections had 2·5–7·9% more precipitation. Upper gauges received less, probably due to turbulence as increased exposure on the top of the slope resulted in precipitation being carried over the gauge orifice. Results confirm that due attention must be given to the inherent variability of precipitation amounts when calculating precipitation inputs. Copyright © 2008 John Wiley & Sons, Ltd.
Spatial prediction of nitrate pollution in groundwaters using neural networks and GIS: an application to South Rhodope aquifer (Thrace, Greece)
Authors: Gemitzi A. , Petalas C. , Pisinaras V. , Tsihrintzis V. A.
Published: October 2008

Neural network techniques combined with Geographical Information Systems (GIS), are used in the spatial prediction of nitrate pollution in groundwaters. Initially, the most important parameters controlling groundwater pollution by nitrates are determined. These include hydraulic conductivity of the aquifer, depth to the aquifer, land uses, soil permeability, and fine to coarse grain ratio in the unsaturated zone. All these parameters were quantified in a GIS environment, and were standardized in a common scale. Subsequently, a neural network classification was applied, using a multi‐layer perceptron classifier with the back propagation (BP) algorithm, in order to categorize the examined area into categories of groundwater nitrate pollution potential. The methodology was applied to South Rhodope aquifer (Thrace, Greece). The calculation was based on information from 214 training sites, which correspond to monitored nitrate concentrations in groundwaters in the area. The predictive accuracy of the model developed reached 86% in the training samples, 74% in the overall sample and 71% in the test samples. This indicates that this methodology is promising to describe the spatial pattern of nitrate pollution. Copyright © 2008 John Wiley & Sons, Ltd.
The pH sensitive probe 5‐(and‐6)‐carboxyl seminaphthorhodafluor is a substrate for the multidrug resistance‐related protein MRP1
Authors: Jin Jing , Jones Arwyn T.
Published: October 2008

Cellular function is dependent on tight regulation of intracellular pH and numerous reports show cancer cells have abnormal pH values in the cytosol and organelles, such as lysosomes. 5‐(and‐6)‐carboxyl seminaphthorhodafluor (SNARF‐1) is a commonly used pH sensitive probe and was used here to determine cytosolic pH of HL‐60 leukemia cells and a drug‐resistant variant overexpressing multidrug‐resistance related protein 1 (MRP1). Resistant cells accumulated significantly less SNARF‐1 compared to parental cells but near control levels of probe accumulation were observed by preincubating cells with the specific MRP1 inhibitor MK571. Two new drug‐resistant cell lines were generated following exposure to doxorubicin or daunorubicin and these upregulated MRP1 or P‐glycoprotein expression, respectively. Experiments in these cells showed that reduced SNARF‐1 accumulation was specific to MRP1 overexpression, as cells upregulating P‐glycoprotein accumulated control levels of the probe. Confirmation that SNARF‐1 is a MRP1 substrate was obtained using K562 and KG1a cells that have been shown to, respectively, constitutively express MRP1 and P‐glycoprotein. Together, the data suggest that SNARF‐1 is a substrate for MRP1 but not P‐glycoprotein, and could therefore be used as a probe to distinguish between expression and activity of these 2 efflux proteins. Finally, we confirm that doxorubicin but not daunorubicin challenged MRP1 overexpressing HL‐60 cells have elevated cytosolic pH. © 2008 Wiley‐Liss, Inc.
A Changing Paradigm of Pelagic Food Webs
Authors: Reynolds Colin S.
Published: October 2008

The paper catalogues the development of knowledge that has increasingly challenged the conventional understanding (the paradigm) that the predominant pathway of energy flow in pelagic systems is founded on the primary production of phytoplankton, its consumption by herbivorous zooplankton and, in turn, the feeding of larger carnivorous animals, including fish of commercial value. Aquatic food webs are now recognised to be more diverse in their carbon sources, more complex in structure and more versatile in their function. Adjacent terrestrial catchments supply nutrients and, crucially, dissolved inorganic carbon, dissolved organic carbon and particulate organic carbon. Pivotal roles in the processing of autochthonous organic carbon are often fulfilled by pelagic microbes and bacterivorous nanoplankton and microplankton. Mesozooplankton consumes algae directly if sufficiently concentrated but is itself a limiting resource to pelagic fish, which either must be specially adapted to gather sufficient zooplankton or must switch to benthic or littoral foods. Opportunistic feeding by such fish, though primarily nourished in the inshore, continues to control abundant zooplankton. Mobility and dietary electivity of adult fish integrate the pelagic food web into that of the benthos. Except in very large lakes and in the open ocean, the influence of benthic food webs influences the flow of carbon within the pelagic and beyond, serving to invalidate the traditional paradigm of trophic relationships and demanding formulation of another.

The flows of matter and energy … result from a simple composition of the activity of individuals and of species

R. Margalef, 1997. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ecotechnology and Emission Control: Alternative or Mutually Promoting Strategies in Water Resources Management?
Authors: Benndorf Jürgen
Published: October 2008

Beyond the traditional paradigm of reducing the loading of water‐bodies by pollutants, during the last four decades the new paradigm of ecotechnology developed in water pollution control. Ecotechnology focuses on minimising the consequences of pollution by intentionally manipulating ecosystem‐internal structures and processes. To promote the new paradigm a new “ecotechnological immission concept” is proposed. The key idea of this new concept states that for non‐toxic, bioconvertible and non bioaccumulating pollutants higher emissions may be granted, if the physical, chemical, and biological structure of the ecosystem has been optimised by ecotechnology to achieve the natural degradation or immobilisation of these substances. All types of pollutants, however, must not exceed ecotechnologically critical limits. Thus, the new “ecotechnological immission concept” integrates emission control and ecotechnology as mutually promoting strategies.

It is the combination of physical characteristics with the chemical and biological processes that makes the various aquatic systems so varied in appearance

D. M. Imboden and A. Wüest (1995). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Climatic Change, Aquatic Science, Multiple Shifts in Paradigms
Authors: Gerten Dieter
Published: October 2008

This paper discusses some recent paradigm shifts in the basic and applied aquatic sciences. Examples for these shifts in thinking are the recognition of climate‐driven synchronies in lake dynamics over large geographic domains, the existence of global‐scale teleconnections in the water system through “virtual water trade”, and the gradual replacement of engineering solutions to water resources management. Furthermore, it is discussed how these scientific breakthroughs relate to the recognition that global climate and environmental change is real, which itself can be considered a paradigm shift. Since these academic paradigm shifts are gradually entering the public discourse, it can be speculated whether they eventually add up to an even more fundamental “sustainability paradigm shift” across all sectors of society.

If philosophy does not resolve any scientific problem, science, in its turn, does not resolve any philosophical problem

Nicolás Gómez Dávila (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Food Web Paradigms: The Biochemical View on Trophic Interactions
Authors: Müller‐Navarra Dörthe C.
Published: October 2008

Different metabolic pathways and requirements can lead to imbalances in the biochemical composition, e.g., between prokaryotes and eukaryotes and between heterotrophic and autotrophic organisms. In addition, heterotrophs cannot synthesize many of the required biochemical constituents themselves but rely in their provision on the feeding environment. If imbalances of essential biochemicals between heterotrophic consumers and their prey are large, those biochemicals can become limiting. The importance of essential ω3‐poly unsaturated fatty acids (PUFAs) for heterotrophic organisms (zooplankton, fish) is well recognized. Especially the conversion of C18‐PUFAs to C20 or C22 highly unsaturated fatty acids (HUFAs) are critical for heterotrophic protists and metazooplankton, and storage may be an adaptation to help overcome limitation. The ecological relevance of cholesterol, essential for arthropods, is still an open question as vertebrates and fungi may be important sources in aquatic systems. Less is known about essential amino acids being limiting. However protein limitation seems to be rare in plankton unless detritus contributes largely to the food. One ecological importance of autotrophs lies in the synthesis of essential biomolecules, promoting growth of heterotrophs. However, vitamin B12 may preferentially originate from prokaryotes (bacteria, cyanobacteria), even limiting growth of certain eukaryotic algae. Measuring the relevant biochemicals, its environmental forcing and cycling (conservation versus alteration in the food web), going beyond food species affiliation and carbon as a unit, but taking the overall food concentration into account will enhance the characterization of C‐cycling and energy flux, irrespectively of the “classical food chain” or “microbial loop”, with implication to human nutrition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Oxygen Controls the Phosphorus Release from Lake Sediments – a Long‐Lasting Paradigm in Limnology
Authors: Hupfer Michael , Lewandowski Jörg
Published: October 2008

The pioneer works of Einsele, Mortimer, and Ohle on the linking between phosphorus (P) and iron (Fe) cycles seven decades ago created the theoretical basis for a long‐standing paradigm among limnologists i.e., ‘oxygen controls the P release from sediments’. While many empirical studies as well as strong correlations between oxygen depletion and P release seem to support this paradigm, various field observations, laboratory experiments, and repeated failures of hypolimnetic oxygenation measures cast doubt on its universal validity. The temporal existence of a thin oxidized sediment surface‐layer could affect only fluctuations of the temporary P pool at the sediment surface but not the long‐term P retention. On longer time scales P release is the imbalance between P sedimentation and P binding capacity of anoxic sediment layers. The P retention of lake sediments strongly depends on sediment characteristics and land use of the catchment. The presence of redox‐insensitive P‐binding systems such as Al(OH)3 and unreducible Fe(III) minerals can enhance the P retention and completely prevent P release even in case of anoxic conditions. Alternative release mechanisms such as a dissolution of calcium‐bound P and decomposition of organic P under both, aerobic and anaerobic conditions, are often more important than the redox driven Fe‐coupled P cycle. Additionally, bacteria affect P cycling not only by altering the redox conditions but also by releasing P during mineralization of organic matter and by accumulation and release of bacterial P. Since microbial processes consume oxygen and liberate P it is difficult to distinguish whether oxygen depletion is the result or the cause of P release. Nowadays, the old paradigm is discarded and a paradigm shift takes place. Sedimentary P exchange ought to be considered as a complex process which is mainly determined by the amount and species of settled P as well as their subsequent diagenetic transformation in the sediment. The classical paradigm is only valid in special cases since reality is much more complex than suggested by that paradigm.

Everything should be made simple as possible, but not simpler!

Albert Einstein (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Control of Lacustrine Phytoplankton by Nutrients: Erosion of the Phosphorus Paradigm
Authors: Lewis William M. , Wurtsbaugh Wayne A.
Published: October 2008

Control of lacustrine phytoplankton biomass by phosphorus is one of the oldest and most stable paradigms in modern limnology. Even so, evidence from bioassays conducted by multiple investigators at numerous sites over the last three decades shows that N is at least as likely as P to be limiting to phytoplankton growth. A number of important flaws in the evidence supporting the phosphorus paradigm have contributed to an unrealistic degree of focus on phosphorus as a controlling element. These include insufficient skeptism in interpretation of: 1) the phosphorus: chlorophyll correlation in lakes, 2) the results of whole‐lake fertilization experiments, and 3) stoichiometric arguments based on total N:total P ratios for inland waters. A new paradigm based on parity between N and P control of phytoplankton biomass in lakes seems more viable than the P paradigm. The new paradigm renews interest in the degree to which plankton communities are molded in composition by small differences in relative availability of N and P, the mechanisms that lead to a high frequency of N limitation in oligotrophic lakes, and the failure of aquatic N‐fixers to compensate significantly for N deficiency under most conditions. A new N/P paradigm still must acknowledge that suppression of P loading often will be the most effective means of reducing phytoplankton biomass in eutrophic lakes, even if N is initially limiting.

From error to error one discovers the entire truth

Sigmund Freud (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Is there a Paradigm Shift in Limnology and Marine Biology?
Authors: Walz Norbert , Adrian Rita
Published: October 2008

To celebrate the 100th anniversary of the International Review of Hydrobiology, we invited leading scientists to contribute to a special issue on Paradigm Shifts in Limnology and Marine Biology. Many of these scientists described new concepts in their highly specialized disciplines, however, not in the strict Kuhnian sense, but more as a cumulative – though nonlinear – acquisition and refinement of knowledge. Hence, a proposal for a major paradigm shift was not presented. If, however, the strict Kuhnian definition is eased somehow, anthropogenically induced global climate change may be regarded as a paradigm shift. Here, we provide a brief overview of these thought‐provoking contributions.

Jedes Problem durchläuft bis zu seiner Anerkennung drei Stufen: In der ersten wird es lächerlich gemacht. In der zweiten bekämpft, in der dritten gilt es als selbstverständlich

Loosely translated: “Everything at first seems ridiculous, is then attacked, and finally is accepted as a matter of course”.

attributed to Arthur Schopenhauer, 1788–1860 (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlating dough elastic recovery during sheeting with flour analyses and rheological properties
Authors: Ren DanQiu , Walker Charles E , Faubion Jon M
Published: October 2008

The dough rheological behaviors of three flours having different chemical and physical properties were measured, as were changes in thickness and snapback (thickness of the machined dough sheet relative to the roll gap), immediately following sheeting. Dough snapback was determined to be a function of processing parameters, reduction ratio, and dough rest time, as well as different flour properties. The predication equation for dough snapback is based on multiple flour properties and sheeting conditions.

Higher protein flours normally have stronger dough properties and larger snapback, compared with low protein flours, but also depend on the protein quality. The snapback will increase either with increased protein content, reduction ratio, or reduced rest time. Dough snapback using flour made by blending two flours 50/50 had intermediate values between the two original flours.

Among the variables, Mixograph work, reduction ratio, and dough rest time were the main factors affecting the elastic characteristics of the doughs. Minimum snapback occurred with the weakest flour experiencing the longest rest time and the smallest reduction ratio. A linear 7‐factor equation was found to predict the snapback of several flours, by combining reduction ratio, dough rest time, Mixograph work, peak height, and mixing time, Alveograph P/L, and protein content. Only three factor combinations of Mixograph work, reduction ratio, and rest time were needed to develop a second order equation for predicting snapback. Copyright © 2008 Society of Chemical Industry