bluuebunny/crossref_metadata_2025 huggingface dataset:
Shielded molecularly imprinted polymers prepared with a selective surface modification
Authors: Watabe Yoshiyuki , Hosoya Ken , Tanaka Nobuo , Kubo Takuya , Kondo Takuya , Morita Masatoshi
Published: March 2005

Uniformly sized, molecularly imprinted polymers (MIPs) of bisphenol A (BPA), one of many potential endocrine disruptors, were prepared by selective surface modification and immobilized at intervals of functional monomers with 4,4′‐methylenebisphenol as a pseudotemplate. MIPs for BPA were prepared with 4‐vinyl pyridine immobilized at the most effective interval and with ethylene glycol dimethacrylate monomer as a functional crosslinker. The prepared MIPs were surface‐modified with both polar and ionic monomers with different modification methods and then evaluated to reveal their selectivity and retention characteristics. Some of the modified MIPs showed significant selectivity for BPA retention when they were used as high‐performance liquid chromatography (HPLC) stationary phases, in comparison with ordinary MIPs. This effect of molecular imprinting was retained even after the surface modification of MIPs. The MIPs employed as pretreatment media for a column‐switching HPLC system provided a detection limit as low as 1 ng/L (ppt) by electrochemical detection. Actual samples, including Suwannee River natural organic matter (NOM), were analyzed for BPA, and BPA was quantitatively detected in NOM even with the combination with widely used UV detection because of the effective removal of interference afforded by an effective surface modification of the MIPs. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2048–2060, 2005
Epitaxial growth of Fe on GaN(0001): structural and magnetic properties
Authors: Calarco R. , Meijers R. , Kaluza N. , Guzenko V. A. , Thillosen N. , Schäpers Th. , Lüth H. , Fonin M. , Krzyk S. , Ghadimi R. , Beschoten B. , Güntherodt G.
Published: March 2005

We report results on growth studies of Fe on GaN, in particular with respect to structural and magnetic properties. The growth of GaN has been carried out by molecular beam epitaxy (MBE) and metal organic vapour phase epitaxy (MOVPE) on Si(111) and Al2O3 substrates, respectively. Fe depositions of different thicknesses were performed in ultra high vacuum (UHV) at room temperature using an electron‐beam evaporation set‐up. X‐ray diffraction analysis shows that the iron films are crystalline and indications of a (110) bcc orientation of the film are observed. By means of scanning tunneling microscopy (STM) epitaxial islands of Fe on the GaN(0001) surface, on a scale of 500 × 500 nm2, have been observed. The experimentally determined magnetic hysteresis loops, with the magnetic field applied parallel to the sample surface, show a coercive field that decreases as the temperature increases; at 300 K and 50 K we measure a coercive field of 12 G and 36 G, respectively. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extraction of temperature and number dependent scattering rates for an AlGaN/GaN 2DEG
Authors: Wells A. , Uren M. J. , Balmer R. S. , Nash K. J. , Martin T. , Missous M.
Published: March 2005

The alloy, polar optical and acoustic phonon scattering terms in the mobility in a GaN HFET have been extracted as a function of temperature and number density. It was found that roughness and Coulomb scattering are insignificant at room temperature. Samples with and without an AlN layer at the AlGaN/GaN interface were compared and used to extract the alloy scattering. At room temperature the mobility was dominated by intrinsic scattering terms. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
White X‐ray microbeam analysis of strain and crystallographic tilt in GaN layers grown by maskless pendeoepitaxy
Authors: Barabash R. I. , Ice G. E. , Liu W. , Einfeldt S. , Hommel D. , Roskowski A. M. , Davis R. F.
Published: March 2005

We describe X‐ray and finite element analysis of dislocations, strain and crystallographic tilt in uncoalesced GaN layers grown by maskless pendeoepitaxy. The experimental results reveal that the GaN wings are tilted upward at room temperature. The distribution of strain and tilt depends on the width‐to‐height ratio of the GaN column. As the width‐to‐height ratio increases the wing tilt increases and changes more abruptly at the column/wing interface. Broadening of the GaN Laue reflections is more pronounced in the column region then in the wing region; this is in line with the inhomogeneity of both the strain and the defect density. A split in the Laue reflections from GaN films at the column/wing interface indicates the development of a low‐angle tilt boundary for samples with a large width‐to‐height ratio of the column. Spacing between the dislocations in the tilt boundary at the column/wing interface for GaN grown with maskless pendeoepitaxy is an order of magnitude larger than the dislocation spacing observed for masked lateral epitaxial growth. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hot‐wall MOCVD grown homoepitaxial GaN layers with intense intrinsic excitonic structure
Authors: Kakanakova‐Georgieva A. , Ivanov I. G. , Hallin C. , Janzén E.
Published: March 2005

We report on a new approach to MOCVD growth of GaN, i.e. hot‐wall MOCVD, and its application to homoepitaxy on GaN substrates. The quality of the epilayers is examined by photoluminescence (PL). Homoepitaxially hot‐wall MOCVD grown GaN layers show (1) intense PL free‐exciton emissions relative to the intensity of the principal bound‐exciton emission and (2) homogeneous cathodoluminescence emission within the terraces developed during the step‐flow growth. Impurity concentrations in the material are measured by secondary ion mass spectrometry (SIMS). (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of the low temperature buffer and annealing on the properties of InN layers grown by MOVPE
Authors: Ruterana P. , Morales M. , Gourbilleau F. , Singh P. , Drago M. , Schmidtling T. , Pohl U. W. , Richter W.
Published: March 2005

InN thin films grown by MOVPE with a thickness of about 100 nm are investigated. Growth was carried out in either two or three steps: deposition of a low temperature nucleation layer at 400 °C and subse‐ quent growth of a thicker InN layer at 530 °C, or use of a GaN buffer layer which was annealed at 1050 °C prior to deposition of the low temperature InN buffer layer. The structural evolution of the layers during a 20 min annealing step at 540 °C under nitrogen was investigated using AFM and XRD. We analyzed the orientation distribution function of the layers by XRD reciprocal space maps applying ψ and χ scans. The results show that the crystalline layer quality is improved by use of a GaN buffer, as also assessed from higher photoluminescence intensity. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reduction of threading dislocations in GaN overgrowth by MOCVD on TiN porous network templates
Authors: Yun F. , Fu Y. , Moon Y. T. , Özgür Ü. , Xie J. Q. , Doğan S. , Morkoç H. , Inoki C. K. , Kuan T. S. , Zhou L. , Smith D. J.
Published: March 2005

GaN overlayers for the purpose of reducing extended defects have been grown by MOCVD on porous network of TiN thin layers which in turn were achieved by in situ nitridation of thin Ti layers (20 nm and 10 nm) on a GaN template. TEM analyses performed for the GaN layer with 20 nm TiN porous netowrk indicate the effectiveness of TiN porous structure in blocking the threading dislocation from penetrating into the upper layer. Plan‐view TEM indicated a reduction in the dislocation density by a factor of 10, compared to the GaN template without TiN network. Subsurface voids were formed during the TiN formation, which act as defect concentrators, and termination sites for dislocations. The reduction in defect density through the use of TiN porous networks is also confimed by X‐ray diffraction data and time‐resolved photoluminescence measurements at room temperature. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Epitaxial Al/GaN and Au/GaN junctions on as‐grown GaN(0001)1 × 1 surfaces
Authors: Orani D. , Piccin M. , Rubini S. , Pelucchi E. , Bonanni B. , Franciosi A. , Passaseo A. , Cingolani R. , Khan A.
Published: March 2005

GaN(0001) epilayers were fabricated by rf‐plasma enhanced molecular beam epitaxy on GaN templates. The templates were grown by metalorganic chemical vapor deposition on sapphire. The layers exhibited the 2 × 2 reconstruction of the Ga‐face during growth and the 1 × 1 reconstruction upon cooling. On such surfaces, Al/n‐GaN and Au/n‐GaN junctions were fabricated in‐situ by molecular beam epitaxy. X‐ray photoemission spectroscopy studies allowed us to determine n‐type Schottky barrier heights of 0.61 ± 0.06 and 0.98 ± 0.06 eV, respectively, for the two types of epitaxial junctions. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemical Vapor Synthesis of Size‐Selected Zinc Oxide Nanoparticles
Authors: Polarz Sebastian , Roy Abhijit , Merz Michael , Halm Simon , Schröder Detlef , Schneider Lars , Bacher Gerd , Kruis Frank E. , Driess Matthias
Published: March 2005

ZnO can be regarded as one of the most important metal oxide semiconductors for future applications. Similar to silicon in microelectronics, it is not only important to obtain nanoscale building blocks of ZnO, but also extraordinary purity has to be ensured. A new gas‐phase approach to obtain size‐selected, nanocrystalline ZnO particles is presented. The tetrameric alkyl‐alkoxy zinc compound [CH3ZnOCH(CH3)2]4 is chemically transformed into ZnO, and the mechanism of gas‐phase transformation is studied in detail. Furthermore, the morphological genesis of particles via gas‐phase sintering is investigated, and for the first time a detailed model of the gas‐phase sintering processes of ZnO is presented. Various analytical techniques (powder XRD, TEM/energy‐dispersive X‐ray spectroscopy, magic‐angle spinning NMR spectroscopy, FTIR spectroscopy, etc.) are used to investigate the structure and purity of the samples. In particular, the defect structure of the ZnO was studied by photoluminescence spectroscopy.
Symmetric and Asymmetric Ostwald Ripening in the Fabrication of Homogeneous Core–Shell Semiconductors
Authors: Liu Bin , Zeng Hua Chun
Published: March 2005

Two methodic concepts, symmetric and asymmetric Ostwald ripening, are elucidated by solution‐route syntheses of oxide and sulfide semiconductors. While the original shape of a crystallite aggregate forms the exterior appearance, the preorganization of the crystallites determines the ultimate interior space structure of the aggregate upon Ostwald ripening. Further investigations on the design of crystallite preorganization and control of the solution process will allow the construction of complex architectures, including nonspherical configurations.
Cover Picture: Cell‐Targeting Multifunctional Nanospheres with both Fluorescence and Magnetism (Small 5/2005)
Authors: Xie Hai‐Yan , Zuo Chao , Liu Yi , Zhang Zhi‐Ling , Pang Dai‐Wen , Li Xiao‐Lan , Gong Jian‐Ping , Dickinson Calum , Zhou Wuzong
Published: March 2005

The cover picture shows hela (human cervical carcinoma) cells that have been incubated with trifunctional nanospheres composed of CdSe/ZnS quantum dots, iron oxide nanoparticles, and folic acid (main picture: bright‐field image; inset: fluorescence image). The nanospheres combine fluorescence, magnetism, and cell recognition properties. For more information, please read the Communication "Cell‐Targeting Multifunctional Nanospheres with both Fluorescence and Magnetism" by D.‐W. Pang, W. Zhou, and co‐workers on page 506 ff.
Caspase‐3 can be pseudo‐activated by a Ca2+‐dependent proteolysis at a non‐canonical site
Authors: Pelletier Maude , Oliver Lisa , Meflah Khaled , Vallette François M.
Published: March 2005

We have shown previously that calcium could trigger nuclear fragmentation, which was associated with a caspase 3 (C3)‐like activity [Juin, P., Pelletier, M., Oliver, L., Tremblais, K., Gregoire, M., Meflah, K. and Vallette, F.M. (1998) Induction of a caspase‐3‐like activity by calcium in normal cytosolic extracts triggers nuclear apoptosis in a cell‐free system. J. Biol. Chem. 273, 17559]. Here, we report that this activation is associated with a non‐canonical truncation of C3, which induces a weak DEVDase activity. The cleavage of C3 via calcium‐dependent proteolysis is independent of caspase 9; lysate exposure to calcium prevents further cleavage and activation by the cytochrome c and dATP pathway. Altogether, our data suggest that calcium could favour a necrotic mechanism by inducing the generation of a form of C3 insensitive to mitochondrial activation.
Perchloric acid‐soluble protein regulates cell proliferation and differentiation in the spinal cord of chick embryos
Authors: Himeno Emi , Yamazaki Kunitaka , Kanouchi Hiroaki , Matsumoto Mitsuharu , Sugimoto Yasushi , Oka Tatsuzo
Published: March 2005

The role of perchloric acid‐soluble protein (PSP) was investigated in chick embryos. Fluorescently labeled anti‐chick liver (CL)‐PSP IgG was injected into the yolk sac in ovo at embryonic day 3, and became localized in neuroepithelial cells. Within 12 h, morphological changes were observed in 37.5% of anti‐CL‐PSP IgG‐injected embryos, and the neuroepithelial cells formed a wavy line. No significant changes were observed in embryos injected with non‐immune IgG or PBS. Increased expression of PCNA and decreased expression of neuronal class III β‐tubulin were observed in the spinal cord after anti‐CL‐PSP IgG injection. These results suggest that PSP controls the proliferation and differentiation of neuroepithelial cells in chick embryos.
On epithets qua attributive anaphors
Authors: CORAZZA EROS
Published: March 2005

A multiple-proposition theory is proposed, according to which a single utterance can express several distinct propositions. An utterance of “Jon, the idiot, missed the train” expresses the official proposition THAT JON MISSED THE TRAIN and the background proposition THAT JON IS AN IDIOT. It is argued that only the official proposition affects the truth-value of the utterance, while the background proposition(s) may be treated similarly to pragmatic presuppositions. The multiple-proposition theory helps us to defend the thesis that, in an utterance such as “Jon1 promised to come but the idiot1 missed the train”, the epithet the idiot must be understood as an attributive anaphor, for it inherits its value from Jon and attributes to Jon the property of being an idiot. It is argued that epithets in such constructions should be viewed in a way similar to quasi-indicators, insofar as the latter are also attributive anaphors. The quasi-indicator she herself in “Jane1 believes that she (herself)1 is rich” inherits its value from Jane and attributes an I-thought to Jane. In focusing on the similarities and differences between epithets and quasi-indicators, we can explain some alleged difficulties, difficulties which suggest that epithets cannot be anaphoric (e.g. “*Jon1 claimed/said/thinks/ … that the bastard1 was honest”). It is shown that the ungrammaticality of sentences like these rests on the fact that the epithet is embedded in what should be a de se attribution (e.g. “Jon1 claimed/said/thinks that he (himself)1 was honest”) while its nature is to contribute to the expression of a de re attribution. This helps us to understand the ungrammaticality of “*Jane1 said/thinks/promised/ … that the idiot1 will come” vs. the grammaticality of “Jane1 said/thinks/promised/ … that she (herself)1 will come” on the one hand, and, on the other hand, the ungrammaticality of “Jon1 ran over a man who was trying to give him (*himself)1 directions” vs. the grammaticality of “Jon1 ran over a man who was trying to give the idiot1 directions”.
Who forgot Paul Broca? The origin of language as test case for speciation theory Jürgen Trabant & Sean Ward (eds.), New essays on the origin of language (Trends in Linguistics). Berlin & New York: Mouton de Gruyter, 2001. Pp. vi+258. Morten H. Christiansen & Simon Kirby (eds.), Language evolution (Studies in the Evolution of Language 3). Oxford: Oxford University Press, 2003. Pp. xvii+395.
Authors: CROW TIMOTHY J.
Published: March 2005

In December 1999, as part of its tricentenary celebrations, the Berlin Academy of Sciences invited eleven speakers to discuss the Origin of Language (cf. the Trabant & Ward volume, henceforth T&W). In March 2000 a workshop (Crow 2002a) under the auspices of the British Academy and the UK Academy of Medical Sciences, ‘The speciation of modern Homo sapiens’, addressed the same problem. The speciation of Homo sapiens and the origins of language are surely two sides of the same coin. At about the same time, the Christiansen & Kirby volume on Language Evolution (henceforth C&K) was conceived at the Fifth Australasian Cognitive Science Conference. Together the contributions of these volumes constitute a substantial contemporary archive on the origin of language. Their publication provides an opportunity to review the status of attempts to account for the evolution of language. Do the contributions converge on a solution?
Do the assemblages of benthic macroinvertebrates in nearshore waters of Western Australia vary among habitat types, zones and seasons?
Authors: Wildsmith M.D. , Potter I.C. , Valesini F.J. , Platell M.E.
Published: March 2005

Benthic macroinvertebrates were sampled seasonally in the subtidal and upper and lower swash zones at two sites in each of six nearshore habitat types on the lower west coast of Australia. The habitat types, which differed mainly in the extent of their exposure to wave activity and whether sea grass and/or nearshore reefs were present, had been distinguished quantitatively using values for a suite of seven statistically-selected enduring environmental characteristics (Valesini et al., 2003). The core samples yielded 121 species representing eight phyla, among which the Polychaeta, Malacostraca and Bivalvia were the most speciose classes, contributing ∼38, 23 and 10%, respectively, to the total number of individuals. The total number of species and mean density of macroinvertebrates at the most protected habitat type (1), i.e. 70 and 209·2 individuals 0·1 m−2, respectively, were far greater than in any other habitat type. Habitat type influenced species composition to a greater extent than either zone or season. Furthermore, the extents of the differences among the species compositions of the six habitat types statistically matched the extents of the differences among the values for the suite of enduring environmental characteristics that distinguished each of those habitat types. Overall, the species composition at habitat type 1 was the most distinct, containing five abundant species of polychaetes that were adapted to deposit-feeding in calm waters with high levels of organic material and which were rare in all other habitat types. In contrast, the fauna at the most exposed habitat type was characterized by four crustacean species and a species of bivalve and polychaete, whose mobility and tough external surface facilitated their survival and feeding in turbulent waters. The zonal differences in faunal compositions among habitat types were greatest in the case of the subtidal zone. The faunal compositions differed among zones and seasons only at the most protected habitat type.
Protection effects on fish assemblages, and comparison of two visual-census techniques in shallow artificial rocky habitats in the northern Adriatic Sea
Authors: Guidetti Paolo , Verginella Laura , Viva Celeste , Odorico Roberto , Boero Ferdinando
Published: March 2005

Fish assemblages associated with shallow (4–7 m deep) artificial rocky habitats (i.e. breakwaters) have been assessed between July 2002 and September 2003, at the marine protected area of Miramare and adjacent areas outside the reserve (northern Adriatic sea). Our purpose was to: (1) detect possible differences between ‘protected vs fished’ breakwaters; and (2) compare two visual-census techniques for fish assessment (i.e. strip transects vs stationary points). The fish assemblages observed between protected and fished breakwaters during all four sampling periods were statistically different. More fish taxa were found at the protected than fished breakwaters, while there was no difference in total fish density. Most fish species targeted by fisheries had a greater density (e.g. Sciaena umbra, Dicentrarchus labrax, Sparus aurata, Diplodus vulgaris, Diplodus sargus and Diplodus puntazzo) and/or size (e.g. S. aurata and D. annularis) at the protected than fished breakwaters. There was a significant difference in fish assemblages due to assessment method. In general, the number of taxa was greater when assessed by strip transects than stationary points. Total fish density was almost unaffected by the method used, while total density of demersal fish (i.e. excluding schooling species) tended to be greater when evaluated by strip transects, although the difference was statistically significant only in one sampling period out of four. These results indicate that protection from fishing may have the potential to influence fish assemblages associated with breakwaters. Additionally, caution should be used when comparing fish assemblage data collected by different visual assessment techniques.
Observations of Alexandrium tamarense (Dinophyceae) vegetative cells and oceanographic parameters in Scapa Flow, Orkney Islands, Scotland
Authors: Joyce Linda B.
Published: March 2005

The toxic dinoflagellate Alexandrium tamarense was studied along with surrounding oceanographic parameters from May 1998 to May 1999 in Scapa Flow, Orkney. Nutrient concentrations were higher in winter and showed a phase of depletion in late spring and summer. Dinoflagellates tended to be abundant in late spring and summer. Alexandrium tamarense was detected in the water column almost year round, with the exception of the winter months (September to December). The growth of the A. tamarense population in Scapa Flow was not reflected in a monospecific bloom but rather in moderate to small biomass levels and always in co-occurrence with other species of diatoms and dinoflagellates. The highest concentration recorded was 1600 cells l−1 but concentrations of 200–400 cells l−1 were more typical. The oceanographic parameters indicate that the occurrences of vegetative cells of A. tamarense seem to be explained in part by instability of the water column, low temperature and low nutrient concentrations.
Contribution of benthic microalgae to ice covered coastal ecosystems in northern Hokkaido, Japan
Authors: McMinn A. , Hirawake T. , Hamaoka T. , Hattori H. , Fukuchi M.
Published: March 2005

Benthic microalgal communities usually make a major contribution to the primary production of estuaries and shallow seas. Pulse amplitude modulation (PAM) fluorometry was used to investigate the contribution of benthic microalgae to the primary production of the Okhotsk Sea coast and Saroma Ko Lagoon in northern Hokkaido. In general the benthic communities had a relatively high biomass but low photosynthetic activity. This led to estimates of 29·2% and 64·5% for the benthic contributions for the 9 m and 3 m depth sites at Mombetsu and 13·1% for Saroma Ko. Sea ice algae provided the greatest contribution at Saroma Ko.
Trophic ecology of a benthic intertidal hydroid, Tubularia crocea, at Mar del Plata, Argentina
Authors: Genzano Gabriel N.
Published: March 2005

The trophic ecology and seasonal changes in the diet of the intertidal hydrozoan Tubularia crocea were studied analysing the enteron contents of hydranths collected each season of the year. The relationship between feeding rate, prey availability, and re-suspension processes caused by tidal currents was also assessed. The most prevalent food items were diatoms and crustaceans. The most remarkable differences occurred during summer, when crustaceans were more abundant than diatoms. Conversely, diatoms were the most abundant prey during other seasons, and they were almost the only prey found during winter. There was no relationship between abundances of primary prey items in the water column and their occurrences in stomach contents. Instead, most prey items consisted of benthic organisms, primarily two species of diatoms (Grammatophora marina and Licmophora abreviatta) and fragments (usually appendages) of the amphipods Caprella sp. and Jassa falcata. Most food items were digested within 4–4·5 hours. The mean number of items captured per polyp per day was determined to be 115·2±19·2 in summer, 93·6±14·4 in autumn, 76·8±21·6 in winter and 199·2±31·2 in spring. Prey biomass (dry weight) polyp−1 d−1 was 5·1 μg in summer, 2·3 μg in autumn, 1·8 μg in winter, and 6·3 μg in spring. These values, in relation to hydranth biomass (55·3 μg; dry weight), were equivalent to a food intake polyp−1 d−1 of 9·3%, 4·2%, 3·2% and 11·5% of its own weight, respectively.
Lessepsian migrants expanding their distributional ranges; Pseudonereis anomala (Polychaeta: Nereididae) in Izmir Bay (Aegean Sea)
Authors: Çinar Melih Ertan , Ergen Zeki
Published: March 2005

A total of ten specimens of Pseudonereis anomala (Polychaeta: Nereididae) were collected on the shallow water hard substratum (0·2 m) at four stations located in the inner part of Izmir Bay (Aegean Sea, eastern Mediterranean) in January 2004. The absence of this species among the material collected previously at the same stations might suggest that it has recently become established in the area. A re-description of the species together with its ecological, reproductive, feeding and distributional aspects are provided.
Geographic range in Chthamalus along the west coast of North America
Authors: Wares J.P. , Castañeda A.E.
Published: March 2005

Identification of the range boundaries and microgeographic distribution of cryptic species is greatly facilitated by the use of genetic markers. Here we characterize the geographic range overlap between two cryptic species, Chthamalus fissus and C. dalli, and show that as with other barnacle species, their distribution and abundance is probably dictated more by microhabitat characteristics and the presence of conspecifics than broader environmental gradients. We also show that C. dalli appears to be panmictic across the studied range.
Larval development of the eastern Pacific anomuran crab Petrolisthes robsonae (Crustacea: Decapoda: Anomura: Porcellanidae) described from laboratory reared material
Authors: García-Guerrero Marcelo U. , Cuesta José A. , Hendrickx Michel E. , Rodríguez Antonio
Published: March 2005

The two zoeal and the megalopal stages of Petrolisthes robsonae, are described and illustrated from laboratory-reared larvae. Larval features are compared with those previously described for other species of Petrolisthes in the eastern Pacific. Larvae of P. robsonae exhibit similar but not identical features to those seen in other Petrolisthes species. A number of similarities are found with P. zacae while main differences are found with P. granulosus,P. platymerus and P. laevigatus. Differences with these species are related to the setation of maxilla and maxillule and the rows of denticles in carapace spines.
Reproductive cycle of purple clam, Amiantis purpurata (Bivalvia: Veneridae) in northern Patagonia (Argentina)
Authors: Morsan Enrique M. , Kroeck Marina A.
Published: March 2005

The reproductive cycle of the purple clam (Amiantis purpurata) northern Patagonian population was studied throughout a 19-month period (September 1993–March 1995) using standard histological techniques and quantitative indicators (oocyte diameter distributions, oocytes per ocular field and relative oocyte area). In this species gametogenesis is a continuous process involving a complete gonadal restitution after the end of the reproductive season (no resting period). The proliferation phase occurs during the coldest half of the year (April to September) and maturation takes place during spring (September to December). Several partial emissions of gametes, with subsequent restitution of the gametogenic series, occur during the summer months. During the total maturation stage, oocytes never filled the whole alveolar area: maximum per cent of alveolar sections occupied by oocytes (46%) was observed in late spring–early summer. Implications of the reproductive pattern in the context of palaeogeographic history of northern Patagonia, and the isolation of this population are discussed.
Life cycle, population dynamics and productivity of Ventrosia maritima in the Evros Delta (northern Aegean Sea)
Authors: Kevrekidis Theodoros , Wilke Thomas
Published: March 2005

Life cycle, population dynamics and productivity of the larviparous mudsnail species Ventrosia maritima were investigated at low salinities (0·3–6 psu) in differentiated parts of a Mediterranean lagoon (Monolimni Lagoon). Monthly samples were collected during the period from February 1998 to February 1999 in both parts of the lagoon. Ventrosia maritima displayed an annual life cycle. Recruitment occurred in summer and autumn at the outer part of the lagoon and additionally in late winter at the innermost part. A positive correlation was found between the percentages of small individuals and salinity or sediment organic matter at the outer part. Growth practically ceased in winter. The mudsnail displayed remarkable densities and an increase in growth in spring at <1 psu indicating that it is highly tolerant to extremely low salinities. Population density showed a significant seasonal variation; it increased from early summer to autumn (30,000–40,000 individuals m−2) following the summer and autumn recruitment. No significant correlation between the density of V. maritima and several examined physicochemical variables was found; a negative correlation was observed between the density of the mudsnail and that of the co-occurring polychaete Streblospio shrubsolii. Secondary production calculated by the size–frequency method gave a mean annual density (N) of 9740 ind m−2, a mean biomass (B) of 1·66 g ash-free dry weight (AFDW) m−2 y−1, a production (P) of 4·51 g m−2 y−1 and a P:B ratio of 2·72 at the outer part of the lagoon and a N of 14,570 ind m−2, a B of 3·2 g AFDW m−2 y−1, a P of 9·9 g m−2 y−1 and a P:B ratio of 3·09 at the innermost part. At the innermost part of the lagoon, where the seawater renewal rate and hydro-dynamism were lower and the sediment finer and organically richer, V. maritima displayed more recruitment pulses, a larger body size and a denser and more productive population than the one at the outer part. Our findings are compared to published data for the direct-developing congeners V. ventrosa and V. truncata.
Styela clava (Tunicata: Ascidiacea)—a new addition to the fauna of the Portuguese coast
Authors: Davis Martin H. , Davis Mary E.
Published: March 2005

The solitary ascidian Styela clava is recorded for the first time in Portuguese waters. It was found at three sites on the west coast of Portugal. This represents the southern limit of its recorded distribution in European waters. The Portuguese specimens are described and compared with UK specimens.
Trophic ecology of the whitemouth croaker, Micropogonias furnieri (Pisces: Sciaenidae), in south-western Atlantic waters
Authors: Sardiña Paula , Cazorla Andrea Lopez
Published: March 2005

Ontogenetic and seasonal diet changes of the juveniles of the marine fish Micropogonias furnieri, a species inhabiting Bahía Blanca estuary (Argentina), were investigated. Two size-related dietary shifts, at 4·00 cm and 7·00 cm total length (LT), respectively, were found. Small juveniles (1·00–3·99 cm LT) ate mostly chaetognaths (Sagitta friderici); medium-sized juveniles (4·00–6·99 cm LT) fed intensively on mysid shrimps (mainly Neomysis americana) and polychaetes, whereas large juveniles (7·00–15·99 cm LT) fed almost exclusively on epibenthic crustaceans (primarily Peisos petrunkevitchi). Increased mouth gape was related to increased size spectrum and mean size of the most important prey items consumed by M. furnieri. Juveniles <510 cm LT ate prey items almost as large as their mouth opening, whereas juveniles >410 cm LT were capable of consuming larger prey items than those found in their stomachs, indicating that the maximum size of prey eaten was not constrained by mouth gape. Seasonal and selectivity dietary analyses showed that M. furnieri can be a highly opportunistic selective feeder. Juveniles relied on S. friderici and P. petrunkevitchi throughout the year, except in summer, when mysids abundance increased in the estuary. Electivity values also showed that prey size and prey relative abundance are important factors in prey selection mechanisms.
Seasonal changes in the north-eastern Atlantic mackerel diet (Scomber scombrus) in the north of Spain (ICES Division VIIIc)
Authors: Olaso Ignacio , Gutiérrez José L. , Villamor Begoña , Carrera Pablo , Valdés Luis , Abaunza Pablo
Published: March 2005

Seasonal changes in the diet of the Atlantic mackerel from the north-east Atlantic in ICES Division VIIIc during the period 1988–1999. The diet of juvenile (21–29 cm) and adult mackerel (30–45 cm) in this area in spring (the spawning season) and autumn varied in composition and size of prey. In spring, the average prey weight was 0·009 g and the number of prey was 180 individuals per stomach, with the average stomach content volume being 1·62 g (0·60% BW [body weight]), and 1·50 g (0·51% BW) when considering the empty stomachs. In autumn, the average prey weight was 0·28 g, the average number of prey per stomach was 17, and the average stomach weight that contained food was three times higher than in spring, and 2·3 times when considering the empty stomachs. In spring, the diet of the juveniles consisted of euphausiids, crustacean larvae and other zooplankton, whereas euphausiids formed 90% of the diet in the adults. In addition, during this period mackerel were cannibalistic, feeding on their own eggs. In autumn, the juveniles ate hyperiids and other, mainly gelatinous zooplankton, whereas for the adults blue whiting were clearly important, since they comprised 90% of the stomach weight.
The40Ar/39Ar dating of core recovered by the Hawaii Scientific Drilling Project (phase 2), Hilo, Hawaii
Authors: Sharp Warren D. , Renne Paul R.
Published: March 2005

The Hawaii Scientific Drilling Project, phase 2 (HSDP‐2), recovered core from a ∼3.1‐km‐thick section through the eastern flanks of Mauna Loa and Mauna Kea volcanoes. We report results of40Ar/39Ar incremental heating by broad‐beam infrared laser of 16 basaltic groundmass samples and 1 plagioclase separate, mostly from K‐poor tholeiites. The tholeiites generally have mean radiogenic40Ar enrichments of 1–3%, and some contain excess40Ar; however, isochron ages of glass‐poor samples preserve stratigraphic order in all cases. A 246‐m‐thick sequence of Mauna Loa tholeiitic lavas yields an isochron age of 122 ± 86 kyr (all errors 2σ) at its base. Beneath the Mauna Loa overlap sequence lie Mauna Kea's postshield and shield sequences. A postshield alkalic lava yields an age of 236 ± 16 kyr, in agreement with an age of 240 ± 14 kyr for a geochemically correlative flow in the nearby HSDP‐1 core hole, where more complete dating of the postshield sequence shows it to have accumulated at 0.9 ± 0.4 m/kyr, from about 330 to <200 ka. Mauna Kea's shield consists of subaerial tholeiitic flows to a depth of 1079 m below sea level, then shallow submarine flows, hyaloclastites, pillow lavas, and minor intrusions to core bottom at 3098 m. Most subaerial tholeiitic flows fail to form isochrons; however, a sample at 984 m yields an age of 370 ± 180 kyr, consistent with ages from similar levels in HSDP‐1. Submarine tholeiites including shallow marine vitrophyres, clasts from hyaloclastites, and pillow lavas were analyzed; however, only pillow lava cores from 2243, 2614, and 2789 m yield reliable ages of 482 ± 67, 560 ± 150, and 683 ± 82 kyr, respectively. A linear fit to ages for shield samples defines a mean accumulation rate of 8.6 ± 3.1 m/kyr and extrapolates to ∼635 kyr at core bottom. Alternatively, a model relating Mauna Kea's growth to transport across the Hawaiian hot spot that predicts downward accelerating accumulation rates that reach ∼20 m/kyr at core bottom (DePaolo and Stolper, 1996) is also consistent with all reliable ages except the deepest.
A new model for multiscale modeling of the Martian atmosphere, GM3
Authors: Moudden Y. , McConnell J. C.
Published: March 2005

A new global model for the Martian atmosphere with a vertical domain extending from the surface into the thermosphere (at about 160–180 km) is presented with some preliminary results. The model is a grid point model with a semi‐Lagrangian semi‐implicit dynamical scheme that is used for weather forecasting by the Meteorological Service of Canada. The physics includes a comprehensive radiative transfer scheme for heating, a boundary and surface layer parameterization. The design of the model allows for different grid configurations that include a globally uniform grid as well as the possibility of zooming over an area of interest with a locally uniform grid. The performance of the model is shown both in global uniform‐resolution simulations as well as high‐resolution simulations over the Tharsis Montes region. The simulated temperatures are compared with the Thermal Emission Spectrometer's measured profiles and the Mars Pathfinder entry data. Both the agreement with the data and the depiction of known features of the Martian atmosphere indicate that the Global Mars Multiscale Model has a good potential for modeling the atmosphere of Mars.
Reentrant onset of chaos in tubular image states
Authors: Segal Dvira , Král Petr , Shapiro Moshe
Published: March 2005

We investigate the reentrant onset of chaos in “tubular image states,” which are loosely bound states of electrons formed in the vicinity (20–40nm) of conducting nanotubes. Chaos is shown to arise when an electron is placed in the vicinity of two metallic nanotubess with a magnetic field applied along the tubes. At stronger magnetic fields B∼10T, we observe the formation of Landau-like states encircling the two-tube system, which wipe out the chaos. We can reinstall the chaos by charging oppositely the nanotubes, thus breaking the symmetry of the system and correspondingly the shape of the Landau-like states. Detailed analysis of the onset of chaos is done by studying the statistical properties of the eigenvalues spectrum and by investigating the spatial autocorrelation functions of individual eigenstates.
Infrared properties of silicon nanoparticles
Authors: Kravets Vasyl G. , Meier Cedrik , Konjhodzic Denan , Lorke Axel , Wiggers Hartmut
Published: March 2005

The optical properties of silicon nanoparticles were measured in the mid-infrared region (2–20μm). The resulting spectra show effects of light scattering as well as absorption features due to excitations of Si–O and Si–H bonds. We are able to model the obtained spectra using an effective medium approach. The nanoparticles are best described using a Si–SiOx core-shell structure. We use the vibrational modes of the oxide to determine the thickness and the stoichiometry of the oxide. Using the Rayleigh scattering limit, we can describe the measured decrease in transmitted intensity. By fitting the theoretically modeled spectrum to the experimental data, we obtain the particle size and shape. Finally, we can identify the surface optical-phonon mode of SiOx, located between the transverse- and longitudinal-optical-phonon frequencies.
Geometry and spin-multiplicity of half-sandwich type transition-metal-benzene complexes
Authors: Rabilloud F.
Published: March 2005

The low lying electronic states of 3d transition-metal-benzene complexes MBz (with M=Sc, V, and Ni) have been investigated by performing complete active space self-consistent field and multireference configuration interaction calculations. Geometries, energetics, and electronic structure are presented and discussed. The results concerning both the geometry and the spin multiplicity of the ground-state contrast with those obtained from previous calculations based on density functional theory. The disagreements between single-reference-based approaches and multireference methods in the characterization of neutral 3d-metal complexes are discussed.
Impedance analysis: A powerful method for the determination of the doping concentration and built-in potential of nonideal semiconductor p-n diodes
Authors: Straub A. , Gebs R. , Habenicht H. , Trunk S. , Bardos R. A. , Sproul A. B. , Aberle A. G.
Published: March 2005

An impedance analysis method is introduced that enables the reliable determination of the doping concentration and the built-in potential of nonideal semiconductor p-n diodes featuring poor values for the shunt resistance, the series resistance, and∕or the diode saturation current. The sample doping concentration on the lightly doped side of the p-n junction and the built-in potential are determined using the classic 1∕C2 vs V representation. The small-signal capacitance C for each reverse bias voltage V is directly extracted from the measured frequency dependence of the sample’s impedance Z. A crucial feature of the method is the determination of the diode’s series resistance and shunt resistance for each reverse bias voltage used. The method is verified using high-quality p-n junction diodes fabricated in silicon wafer substrates and its capabilities are demonstrated on nonideal p-n junction diodes fabricated in polycrystalline silicon thin films on glass substrates.
Quantitative measure of nanoscale adhesion hysteresis by ultrasonic force microscopy
Authors: Szoszkiewicz R. , Kulik A. J. , Gremaud G.
Published: March 2005

Adhesion hysteresis is the difference between the work used on separating two surfaces and the work gained on bringing them back together. Although much effort has been invested into adhesion hysteresis investigations at macroscales and microscales, its measurements at the nanolengths or even molecular lengths are still not easy. In this paper we demonstrate how to obtain quantitative measures of local adhesion hysteresis from ultrasonic force microscopy investigations. We derive analytical models fitting all the experimental cases and apply them to experimental data.
Mechanism of the CO oxidation reaction on O-precovered Pt(111) surfaces studied with near-edge x-ray absorption fine structure spectroscopy
Authors: Nakai I. , Kondoh H. , Amemiya K. , Nagasaka M. , Shimada T. , Yokota R. , Nambu A. , Ohta T.
Published: March 2005

The mechanism of CO oxidation reaction on oxygen-precovered Pt(111) surfaces has been studied by using time-resolved near-edge x-ray absorption fine structure spectroscopy. The whole reaction process is composed of two distinct paths: (1) a reaction of isolated oxygen atoms with adsorbed CO, and (2) a reaction of island-periphery oxygen atoms after the CO saturation. CO coadsorption plays a role to induce the dynamic change in spatial distribution of O atoms, which switches over the two reaction paths. These mechanisms were confirmed by kinetic Monte Carlo simulations. The effect of coadsorbed water in the reaction mechanism was also examined.
Evolution of the structure of amorphous ice: From low-density amorphous through high-density amorphous to very high-density amorphous ice
Authors: Martoňák R. , Donadio D. , Parrinello M.
Published: March 2005

We report results of molecular dynamics simulations of amorphous ice for pressures up to 22.5 kbar. The high-density amorphous ice (HDA) as prepared by pressure-induced amorphization of Ih ice at T=80K is annealed to T=170K at various pressures to allow for relaxation. Upon increase of pressure, relaxed amorphous ice undergoes a pronounced change of structure, ranging from the low-density amorphous ice at p=0, through a continuum of HDA states to the limiting very high-density amorphous ice (VHDA) regime above 10 kbar. The main part of the overall structural change takes place within the HDA megabasin, which includes a variety of structures with quite different local and medium-range order as well as network topology and spans a broad range of densities. The VHDA represents the limit to densification by adapting the hydrogen-bonded network topology, without creating interpenetrating networks. The connection between structure and metastability of various forms upon decompression and heating is studied and discussed. We also discuss the analogy with amorphous and crystalline silica. Finally, some conclusions concerning the relation between amorphous ice and supercooled water are drawn.
Pumping of liquids with traveling-wave electroosmosis
Authors: Ramos A. , Morgan H. , Green N. G. , González A. , Castellanos A.
Published: March 2005

Net flow of electrolyte induced by a traveling-wave electric potential applied to an array of microelectrodes is reported. Two fluid flow regimes have been observed: at small-voltage amplitudes the fluid flow follows the direction of the traveling wave, and at higher-voltage amplitudes the fluid flow is reversed. In both cases, the flow seems to be driven at the level of the electrodes. The experiments have been analyzed with a linear electroosmotic model based upon the Debye–Huckel theory of the double layer. The electrical problem for the experimental interdigitated electrode array is solved numerically using a truncated Fourier series. The observations at low voltages are in qualitative accordance with the electroosmotic model.
Effects of internal noise for rate oscillations during CO oxidation on platinum surfaces
Authors: Hou Zhonghuai , Rao Ting , Xin Houwen
Published: March 2005

We have studied the influence of internal noise on the reaction rate oscillation during carbon-monoxide oxidation on single crystal platinum surfaces using chemical Langevin equations. Considering that the surface is divided into small well-mixed cells, we have focused on the dynamic behavior inside a single cell. Internal noise can induce rate oscillations and the performance of the stochastic rate oscillations shows double maxima with the variation of the internal noise intensity, demonstrating the occurrence of internal noise coherent biresonance. The relationship between such a phenomenon with the deterministic bifurcation features of the system is also discussed.
Femtosecond laser-induced refractive index modification in multicomponent glasses
Authors: Bhardwaj V. R. , Simova E. , Corkum P. B. , Rayner D. M. , Hnatovsky C. , Taylor R. S. , Schreder B. , Kluge M. , Zimmer J.
Published: March 2005

We present a comprehensive study on femtosecond laser-induced refractive index modification in a wide variety of multicomponent glasses grouped as borosilicate, aluminum–silicate, and heavy-metal oxide glasses along with lanthanum–borate and sodium–phosphate glasses. By using high-spatial resolution refractive index profiling techniques, we demonstrate that under a wide range of writing conditions the refractive index modification in multicomponent glasses can be positive, negative, or nonuniform, and exhibits a strong dependence on the glass composition. With the exception of some aluminum–silicate glasses all other glasses exhibited a negative/nonuniform index change. We also demonstrate direct writing of waveguides in photosensitive Foturan® glass with a femtosecond laser without initiating crystallization by thermal treatment. Upon ceramization of lithium–aluminum–silicate glasses such as Foturan®, Zerodur®, and Robax® we observe switching of laser-induced refractive index change from being positive to negative. The measured transmission losses in the waveguides at 1550nm agree with the index profile measurements in alkali-free aluminum–silicate glasses.
Inexpensive Wilhelmy balance based in a fiber optic sensor for the study of Langmuir films
Authors: Gutiérrez Héctor M. , Castillo Jimmy A. , Chirinos José R. , Caetano Manuel
Published: March 2005

An inexpensive Wilhelmy balance based on a fiber optic sensor capable of sensitive surface tension measurements has been designed and implemented. The system consists of a leaf spring conforming a cantilever structure and a bifurcated optical fiber acting as a laser beam deflection detector. Operated in a static way, it achieves a force measurement sensitivity of 0.154 V by N and a tension surface resolution of 0.1 mN/m. π-A isotherms of Langmuir films from insoluble amphiphiles 5 hexadecanoylaminofluorescein (fluorescein H-110) in water, were followed as a model system to characterize this instrument.