bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards tracking marine larvae with in situ hybridization
Authors: Le Goff-Vitry Marie C. , Jacquelin Sandrine , Comtet Thierry
Published: October 2007

Marine invertebrate larvae represent a transitory, but nonetheless important component of planktonic communities. Assessing their contribution to plankton diversity has been hindered by numerous methodological difficulties, notably at the identification step. For many sessile invertebrates, planktonic larvae also play a crucial role, as they are their sole dispersal vectors. Understanding connectivity patterns among marine populations is fundamental for managing coastal ecosystems and their associated resources. Indirect approaches, relying on population genetics models, have widely contributed to elucidate population structure and gene flow patterns, but show, in some cases, conflicting results with larval dispersal potential. In an attempt to facilitate surveys of larval distributions and abundances, an in situ hybridization on whole larvae method was tested over a range of marine invertebrate larvae collected from environmental plankton samples. Ribosomal RNA-targeted oligonucleotide probes were used for hybridization, followed by a colorimetric reaction allowing signal detection at the light microscope. Promising results were obtained, showing an unambiguous positive hybridization signal with a eukaryotic (positive) probe, but no signal with a negative probe. Using species-specific probes, the method could be applied to resolve key current questions in marine ecology, addressing both wide and fine scales.
A new marine ciliate, Tachysoma multinucleata sp. nov. (Ciliophora: Oxytrichidae)
Authors: Gong Jun , Choi Joong Ki
Published: October 2007

The morphology and infraciliature of a new marine ciliate, Tachysoma multinucleata sp. nov., collected from the Jawol Island near Incheon, Korea, were investigated using live observation and protargol impregnation. The new species is characterized by: size in vivo about 65×25 μm, body oval to ellipsoid. Three frontal, one buccal, four frontoventral, three ventral and two pretransverse cirri. Fifteen to 22 left and 13–21 right marginal cirri and about 21–27 adoral membranelles. Cortical granules fine and yellowish, arranged around cirri and dorsal cilia. Usually 12–26 macronuclear nodules. Three dorsal kineties. Marine habitat.
Day-night activity rhythm of the cold seep shrimp Alvinocaris stactophila (Caridea: Alvinocarididae) from the Gulf of Mexico
Authors: Aguzzi Jacopo , Ramirez-Llodra Eva , Telesnicki Guy , Camps Mercedes
Published: October 2007

The activity rhythm of the cold seep shrimp Alvinocaris stactophila from the Gulf of Mexico slope (650 m depth) was investigated in the laboratory in relation to an artificial 12 h light-dark regime. Animals were sampled with a submersible and transferred into individual aquaria where their activity was monitored for 5 d by taking digital video snapshots every 30 s. An observer analysed the footage by counting the number of times an animal crossed two perpendicular lines drawn on a PC screen per 30 min interval. Resulting time series were represented over consecutive days and the waveform analysis was used to precisely assess the phase (i.e. the peak timing) and its limits (i.e. onset and offset) in relation to light ON and OFF. The majority (73%) of animals showed a marked nocturnal pattern of activity with number of movements close to zero during the photophase. Waveform analysis showed that the behavioural transition from activity to inactivity after light ON occurred within approximately 1 h. Considering the general lack of knowledge on the regulation of activity rhythms of crustaceans from subtidal areas, the present data provide a new insight on the role played by light in the regulation of animal activity rhythm in deep-water environments such as those of the cold seeps in the Gulf of Mexico.
The red blenny Parablennius ruber in the British Isles, with notes on field identification characteristics and ecology
Authors: Goodwin C.E. , Picton B.E.
Published: October 2007

Parablennius ruber, the red or Portuguese blenny, is reported from the British Isles. This species has recently been revalidated as separate from P. gattorugine and this, together with confusion about the field identification characteristics which distinguish the two species, is likely to have resulted in it being under-recorded. Parablennius ruber was found to be fairly widespread on the exposed west coasts of the Republic of Ireland and Scotland (22 records), with additional records from the Isles of Scilly (3 records) and Northern Ireland (1 record). One record was made of egg guarding. Most records were from exposed areas of bedrock and boulders, between 15 and 30 m in depth. Field identification characteristics which distinguish between P. ruber and P. gattorugine are given. Given that its original description was from Ushant in 1836, it is unlikely that P. ruber is a fairly recent addition to the British fauna as a result of increased water temperatures. However, given its habitat, the fairly recent advent of sampling by SCUBA diving is likely to have increased the potential for sightings. The growth of SCUBA diving and the increase in the use of underwater digital photography are likely to result in a better knowledge of its distribution.
Nebalia kocatasi sp. nov., a new species of leptostracan (Crustacea: Phyllocarida) from Izmir Bay (Aegean Sea, eastern Mediterranean)
Authors: Moreira Juan , Kocak Cengiz , Katagan Tuncer
Published: October 2007

Nebalia kocatasi sp. nov. (Crustacea: Leptostraca) is described from specimens collected off the coast of Turkey (Aegean Sea). The new species differs from the other known species of the genus in having a rostrum about 2.4 times as long as wide, the antennular scale is twice as long as wide, the third article of the antennule has up to four short distal spines, the third article of the antenna has three robust spines on the external lateral face, the two distalmost being the longest, the endopod of the second maxila is composed of two sub-equal articles, the exopod of the second maxilla is as long as the first article of the endopod, pleonites 6–7 have pointed denticles along the posterior dorsal borders, the protopod of pleopod 4 has 2–3 serrations along the posterior border and the terminal seta of the caudal furca is about twice the length of rami. This is the second leptostracan species reported to date from the eastern Mediterranean.
The establishment of the invasive alga Sargassum muticum on the west coast of Scotland: a preliminary assessment of community effects
Authors: Harries D.B. , Harrow S. , Wilson J.R. , Mair J.M. , Donnan D.W.
Published: October 2007

Comparative studies were conducted on intertidal algal and faunal communities associated with Sargassum muticum and native algae on the Isle of Cumbrae, Scotland. Significant differences were detected in the structure and composition of the communities. The abundance of the dominant native algae Dictyota dichotoma was found to be reduced in areas dominated by S. muticum and displacement through competition for substrate or light is inferred. Elevated faunal abundances were associated with S. muticum and evidence indicates that increased detrital input may be a possible contributory factor. Differences in faunal community composition were most pronounced in the sessile epifauna below the S. muticum canopy. Faunal communities associated with S. muticum were less heterogeneous in composition than those associated with native algae at equivalent shore positions. Some of the compositional differences may be coincidental and attributable to factors favouring the establishment of S. muticum rather than to the direct influence of the S. muticum canopy.
Anthropogenic impacts on the Corner Rise seamounts, north-west Atlantic Ocean
Authors: Waller Rhian , Watling Les , Auster Peter , Shank Timothy
Published: October 2007

Here we report the first direct underwater observations of extensive human-caused impacts on two remote seamounts in the Corner Rise complex (north-western Atlantic). This note documents evidence of anthropogenic damage on the summits of Kükenthal peak (on Corner Seamount) and Yakutat Seamount, likely resulting from a limited Russian fishery from the mid-1970s to the mid-1990s, highlighting how bottom trawling can have long-term detrimental effects on deep-water benthic fauna.
Aspects of the biology of carcharhiniform sharks in Indonesian waters
Authors: White William T.
Published: October 2007

A total of 13 species of carcharhiniform sharks (excluding the families Carcharhinidae and Sphyrnidae) belonging to four families was recorded in fish landing site surveys in eastern Indonesia. Of these, the Triakidae were most abundant in the landings with Hemitriakis sp. 1 and Mustelus cf. manazo both contributing 1.8% to the total number of all sharks recorded. A number of the species, i.e. Atelomycterus baliensis, Halaelurus sp. 1, Hemitriakis sp. 1, Mustelus cf. manazo and Mustelus widodoi, were first recognized during these landing site surveys. A size at maturity for males of the two most abundant scyliorhinids, Atelomycterus marmoratus and Halaelurus sp. 1, could not be accurately determined, but they attained maturity at 419–506 and 360–404 mm TL, respectively. The latter species displays multiple oviparity with the uteri of pregnant females possessing six or 12 egg cases, each containing early to mid-term embryos. The length at first maturity (L50) of males of Hemitriakis sp. 1 and M. cf. manazo was 900 and 859 mm TL, respectively, and the length at birth was approximately 280 mm TL in both species. The mode of reproduction in both of these species was viviparous, with histotrophy. The most abundant hemigaleid species, H. microstoma, was found to mature at a far larger size than the only other congeneric species H. australiensis, i.e. 750–780 vs 600–650 mm TL, respectively. The data presented in this paper are the first such biological data reported on six of these shark species and are thus vital for fisheries managers and conservation assessors, especially given the extent of the shark and ray fisheries in Indonesia.
The reproductive cycle and size at maturity observed in the velvet swimming crab, Necora puber, in the Shetland Islands, Scotland
Authors: Tallack Shelly M.L.
Published: October 2007

Seasonality of the reproductive cycle for Necora puber was determined using three biological indicators: extruding sperm plugs (mating period), extrusion of eggs (spawning period) and presence of empty egg capsules (hatching period). Sperm plugs were found only in recently moulted females, indicating that mating coincides with moulting periods. Necora puber mating indicators were observed during the summer months and into autumn; spawning was observed year-round but peaked in the summer; hatching was observed throughout the summer into late autumn. Size at maturity was assessed using a variety of reproductive and morphometric criteria; estimates from reproductive criteria are generally larger than those from morphometric criteria and these differences are often indicative of ‘functional’ vs ‘behavioural’ maturity. Size at maturity estimates for N. puber in Shetland ranged from 40.0–49.9 mm CW in males and 51.8–59.5 mm CW in females; sizes at functional maturity were larger than sizes derived from morphometric indicators.
On Latin, English and capable hands; From the New Editors
Authors: McArthur Tom
Published: October 2007

Not long ago, I came across Tore Janson's A Natural History of Latin: The story of the world's most successful language (2004) – and I thought: ‘That's an odd claim.’ Then four things came to mind: the Roman Empire, which lasted for centuries; the Roman Catholic church, which has lasted longer; Latin as Europe's international language, and the Romance language family (‘Latin’ under other names). In the later twentieth century, the teaching of Latin itself fell on hard times, which for me – a teacher of the language some decades ago – is a matter of regret. It was a pleasure therefore to encounter Janson's book, which (mirabile dictu) came out first in Swedish then in English.
Researching and teaching China and Hong Kong English
Authors: Li David C. S.
Published: October 2007

THE ENGLISH curriculum in China – including the Hong Kong Special Administrative Region (HKSAR) – has traditionally been dominated by native-speaker (NS) based pedagogical models. This is a source of many problems, ranging from learning outcome to teaching performance, and from cultural inappropriacy to speaker identity. Research in World Englishes (WE), in English as a lingua franca (ELF) and an international language (EIL), and to a lesser extent in second-language acquisition (SLA) has shown that a curriculum informed by a deficit model (by measuring learner performance using the yardstick of native-speaker-based standards) is by its very nature disempowering, and should be replaced with a model of difference, whereby learners' L1 identities and ownership of English are both respected.
Two-year-olds' productivity with verbal inflections
Authors: HOHENSTEIN JILL , AKHTAR NAMEERA
Published: October 2007

Previous research has examined children's ability to add inflections to nonsense words. The current experiments were designed to determine whether children, ranging in age from 1 ; 9 to 2 ; 10 (N=34), could demonstrate productivity by dropping verbal inflections. In Experiment 1, children added -ed and -ing to novel stems, and dropped them from novel inflected forms and did so largely appropriately. In Experiment 2, they dropped -ing from verbs, but not from nouns, suggesting that when young children drop inflections they tend to do so appropriately, and not simply for ease of pronunciation.
The acquisition of two phonetic cues to word boundaries
Authors: REDFORD MELISSA A. , GILDERSLEEVE-NEUMANN CHRISTINA E.
Published: October 2007

The study evaluated whether durational and allophonic cues to word boundaries are intrinsic to syllable production, and so acquired with syllable structure, or whether they are suprasyllabic, and so acquired in phrasal contexts. Twenty preschool children (aged 3 ; 6 and 4 ; 6) produced: (1) single words with simple and complex onsets (e.g.nailvs.snail); and (2) two-word phrases with intervocalic consonant sequences and varying boundary locations (e.g.this nailvs.bittysnail). Comparisons between child and adult control productions showed that the durational juncture cue was emergent in the four-year-olds' productions of two-word phrases, but absent elsewhere. In contrast, the allophonic cue was evident even in the three-year-olds' productions of single words. Perceptual judgments showed that age- and type-dependent acoustic differences translated into differences in listener behavior. The differential acquisition of the two juncture cues is discussed with reference to the acquisition of articulatory timing control.
Approximate characterizations of projectivity and injectivity for Banach modules
Authors: PIRKOVSKII A. YU.
Published: October 2007

We characterize projective and injective Banach modules in approximate terms, generalizing thereby a characterization of contractible Banach algebras given by F. Ghahramani and R. J. Loy. As a corollary, we show that each uniformly approximately amenable Banach algebra is amenable. Some applications to homological dimensions of Banach modules and algebras are also given.
Boundary links are self delta-equivalent to trivial links
Authors: SHIBUYA TETSUO , YASUHARA AKIRA
Published: October 2007

Self Δ-equivalence is an equivalence relation for links, which is stronger than link-homotopy defined by J. W. Milnor. It was shown that any boundary link is link-homotopic to a trivial link by L. Cervantes and R. A. Fenn and by D. Dimovski independently. In this paper we will show that any boundary link is self Δ-equivalent to a trivial link.
Finitary and Artinian-finitary groups
Authors: WEHRFRITZ B. A. F.
Published: October 2007

Let M be a module over the ring R. The finitary automorphism group of M over R is

and the Artinian-finitary automorphism group of M over R is

We continue our study begun in [9] and [12] of the relationship between these two in some ways similar, but actually quite different types of automorphism group. Our study here involves the generalized finitary group $\{{\rm g} \in {\rm Aut}_{\rm R}{\rm M}{:}\,{\rm M}({\rm g} - 1)$ embeds into some finitely generated R-module which does not fit our earlier pattern of generalized finitary groups as described in [8].
The Mehri Participle: Form, Function, and Evolution
Authors: Rubin Aaron D.
Published: October 2007

The verbal form known as the active participle (= AP) is an integral part of the Mehri verbal system, functioning mainly – but not exclusively – as a future tense.1Yet despite its frequency, recent synopses of the language have given this form very little attention. For example, in the very important sketch of the Modern South Arabian languages by Johnstone (1975), discussion of the AP is limited to less than one sentence (p. 119). In the very useful set of observations by Lonnet (1994a), the AP receives only a little more consideration, about ten lines. In the more recent outline by Simeone-Senelle (1997), the AP also gets about ten lines. All of this is in contrast to the grammar of Jahn (1905), in which the AP (or future, as Jahn calls it) is treated as a basic verbal tense and is included in all paradigm sets.2
Von der Diagnose zum Nachweis der Vogelgrippe beim Menschen
Authors: Wunderli
Published: October 2007

Obwohl das Virus der Vogelgrippe ausschließlich an das Geflügel angepasst ist, kommen immer wieder Erkrankungen beim Menschen vor. Warum ist dies trotzdem möglich und wie groß ist die Gefahr, dass sich das Virus trotzdem soweit anpassen kann, dass es leicht von Mensch zu Mensch übertragen werden kann? Bis heute sind zwei Mechanismen genauer untersucht, die es dem Virus erlauben, sich so an den Menschen anzupassen, dass es im neuen Wirt leicht übertragbar wird. Dies sind folgende Vorgänge: – Anpassung durch Anhäufung von Mutanten an wichtigen Stellen des Genoms. – Anpassung durch den Austausch von Genomsegmenten verschiedener Typen von Influenza. Bis jetzt ist eine Anpassung aber nicht erfolgt. Erkrankungen wurden nur nach engem Kontakt mit infiziertem Geflügel beobachtet. Es gibt Hinweise, dass kontaminierte Ausscheidungen der Tiere (Staub) in die unteren Atemwege gelangen können, wo dann die Infektion erfolgt. Klinisch zeigt die Erkrankung mit Vogelgrippe zu Beginn vergleichbare Symptome einer normalen Grippe. Im weiteren Verlauf der Krankheit führt der Befall der unteren Atemwege häufig zu den entsprechenden Komplikationen. Wegen der Ähnlichkeit der Symptome müssen Laboruntersuchungen weiterhelfen, um Verdachtsfälle abzuklären. Ideal wäre die Verwendung eines Schnelltests, um bei einem Verdachtspatienten eine Infektion rasch ausschließen zu können. Leider sind bis jetzt all diese Methoden zuwenig empfindlich, sodass nur mittels der hochempfindlichen RT-PCR eine Infektion bei einem Verdachtpatienten sicher bestätigt oder ausgeschlossen werden kann.
Antivirale Medikamente zur Behandlung und Prophylaxe der Influenza
Authors: Nüesch
Published: October 2007

Falls Influenza nicht durch eine Impfung verhindert werden kann, stellen die antiviralen Medikamente die wirksamste Behandlungsmöglichkeit dar. Zwei Substanzklassen, Adamantane und Neuraminidasehemmer sind gegen Influenzaviren aktiv, wobei die Neuraminidasehemmer den größten Fortschritt in der Therapie der Influenza darstellen. Die Wirksamkeit der Neuraminidasehemmer zur Therapie der im Labor und auf natürlichem Weg erworbenen Influenza wurde in experimentellen sowie klinischen Studien klar belegt. Virusausscheidung, Schweregrad der Symptome, Krankheitsdauer und Zeit bis zur Wiederaufnahme der normalen Aktivität werden durch eine Therapie signifikant reduziert. Ebenfalls reduziert sich die Anzahl von sekundären Komplikationen wie Pneumonie oder Otitis, die Anzahl Hospitalisationen und der Antibiotikagebrauch. Die Wirkung ist umso ausgeprägter, je früher die Medikamente im Krankheitsverlauf eingenommen werden. Neuraminidasehemmer lassen sich auch in der primären und postexpositionellen Prophylaxe einsetzen und Stellen eine der wichtigsten Optionen im Falle einer Pandemie dar.
A Bioavailability Study Comparing Two Oral Formulations Containing Zinc (Zn Bis-Glycinate vs. Zn Gluconate) After a Single Administration to Twelve Healthy Female Volunteers
Authors: Gandia  , Bour  , Maurette  , Donazzolo  , Duchène  , Béjot  , Houin
Published: October 2007

As the current nutritional zinc intake frequently falls outside the Dietary Reference Intake (DRI) and as zinc is an essential trace mineral involved in the function of many enzymes, zinc supplementation has been recommended to prevent or treat the adverse effects of zinc deficiency. The aim of the present study was to compare the oral bioavailability of zinc bis-glycinate (a new formulation) with zinc gluconate (reference formulation). A randomized, cross-over study was conducted in 12 female volunteers. The two products were administrated orally at the single dose of 15 mg (7.5 mg × 2), with a 7-day wash-out period between the two tests. Serum concentrations of zinc were assayed by a validated inductively coupled plasma optical emission spectrometry (ICP-OES) method and Cmax, TCmax, and areas-under-the-curve (AUCs) were determined. The comparison between the two treatments was performed by comparing the Cmax, AUCt, and AUCi using an analysis of variance followed by the calculation of the 90% confidence intervals of the ratio test/reference. Bis-glycinate administration was safe and well tolerated and bis-glycinate significantly increased the oral bioavailability of zinc (+43.4%) compared with the gluconate.
Microstructures and rheology of hydrous synthetic magmatic suspensions deformed in torsion at high pressure
Authors: Arbaret Laurent , Bystricky Misha , Champallier Rémi
Published: October 2007

The relationship between magma rheology and characteristic magmatic microstructures was investigated by performing high‐temperature high‐pressure deformation experiments on hydrous synthetic magmatic suspensions in the range of 0% to 76% solid fraction (alumina grains). Torsion experiments were conducted at 300 MPa confining pressure, temperatures ranging from 475°C to 1000°C and shear strain rates ranging from 2.0 × 10−5 to 2.1 × 10−3 s−1 up to total strains of 21.3. Flow is Newtonian for a solid fraction of φs = 0.0–0.16 with a log dynamic viscosity η = 10.3 Pa s (T = 500°C). A deviation from Newtonian behavior is observed for φs > 0.16 with an increase in apparent viscosity of about 1 order of magnitude between φs = 0.16 and 0.54. The shape fabric of the solid phase is characterized by a unimodal orientation that is almost stable and nearly parallel to the shear direction. Both shape fabric and deviation from Newtonian behavior originate from the increase in the number of particle clusters in the suspension. The apparent viscosity increases by 1.5 orders of magnitude between φs = 0.54 and 0.65, and extrapolation of the data suggests a very sharp increase in apparent viscosity for φs ≥ 0.65. At T ≥ 550°C and φs = 0.54 the solid phase forms an almost entirely connected network composed of two alternating orientation domains. At T ≤ 550°C and φs = 0.65, intragranular fracturing and tensile fractures result from high local stresses at contact points between neighboring particles. The resulting bulk extensional fabric is almost parallel to the shortening direction.
Geometry and dynamics of wave ripples in the nearshore zone of a coarse sandy beach
Authors: Masselink G. , Austin M. J. , O'Hare T. J. , Russell P. E.
Published: October 2007

Extensive measurements of ripple characteristics and dynamics along with associated suspended sediment fluxes and hydrodynamic conditions were made in the shoaling and surf zones of a macrotidal coarse grained beach at Sennen Cove, Cornwall, England (median grain diameter 0.69 mm). Suborbital vortex ripples were observed during the majority of the study period with height ∼5 cm and length ∼35 cm. The scale and shape of the ripples did not vary significantly as the bed shear stress increased during wave shoaling and breaking. However, ripple migration rates (onshore directed) were strongly dependent on their location relative to the breakpoint, increasing from ∼0.1 cm min−1 under shoaling waves to 2 cm min−1 in the outer surf zone during low‐energy conditions. Farther inside the surf zone, ripples persisted but migration rates slowed, probably owing to the presence of the offshore‐directed mean flow which impedes landward migration of the ripples. Under low‐wave conditions (during which measured sediment fluxes peaked around the outer surf zone and decreased through the saturated surf zone), bed form transport rates under shoaling waves were of the same magnitude as net suspended sediment fluxes but at least an order of magnitude smaller in the outer surf zone. Under high‐energy conditions (during which suspended sediment fluxes in the surf zone were offshore directed owing to the presence of the seaward directed mean flow), bed form transport rates were several orders of magnitude smaller than suspended fluxes.
Radiative transfer modeling of lunar highlands spectral classes and relationship to lunar samples
Authors: Cahill J. T. , Lucey P. G.
Published: October 2007

Tompkins and Pieters (1999) identified eleven spectral classes present on the surface of the Moon. Here we model these spectral classes to determine the compositions that define them. We do this by mathematically matching spectral classes to radiative transfer computed spectra using spectral shape, contrast, and excursion parameters as defining characteristics. Model spectra are based upon known mineralogies, mafic‐mineral Mg′s (molar (Mg/(Mg + Fe)) · 100), and maturities. We compare these compositional results to a compilation of ∼100 Apollo samples to determine plausible representative samples for these spectra. Results indicate that unique mineralogic solutions for several spectral classes can be determined unambiguously; however, classes previously interpreted to be pyroxene‐rich are compositionally ambiguous. Results suggest these ambiguous mineral assemblages are not random, but correlate with variations in absolute reflectance. These data further suggest absolute reflectance is a compositionally diagnostic spectral parameter that should be used in conjunction with relative reflectance analysis to constrain mineralogy. Although absolute reflectance for the eleven spectral classes is not available to constrain their composition, we detail mineral, chemical (i.e., Mg′), and absolute reflectance variations of matching model relative reflectance spectra to narrow the possibilities. This information is used in a pilot study of Bullialdus crater, for which Clementine absolute reflectance is known. Results indicate Bullialdus's central peak consists of Tompkins and Pieters' spectral classes AN, AGN, and N. Bullialdus's spectra that match class N are roughly consistent with previous compositional interpretations; however, matches to classes AN and AGN indicate more mafic assemblages typical of Mg‐suite norite/gabbronorite rocks.
Numerical modeling of tidal influence on density‐dependent contaminant transport
Authors: Brovelli A. , Mao X. , Barry D. A.
Published: October 2007

Transport of contaminants in coastal aquifers subject to tidal fluctuation is an important topic in hydrogeology as a consequence of the significant development of human activities near the shoreline. Despite this, relatively little work has been done to investigate the joint effect of variable water density flow and tidal saltwater head fluctuation. In particular, numerical modeling results have rarely been validated with experimental data. The primary aim of this work was to develop and validate a modeling strategy to incorporate the effect of tides in a variable density simulation using a widely adopted simulation package. The numerical model reproduced data from a laboratory experiment designed to investigate the impact of tides on conservative contaminant transport in a coastal aquifer, where the polluted water is denser than the ambient groundwater. Both the plume shape and size were reproduced when tidal fluctuations were incorporated in the model. Model simulations were then used to examine in detail how the flow patterns are modified during one tidal cycle. According to the simulations, the contaminant was mainly discharged from the beach surface. The model was also used to investigate the contact between the contaminant plume and the saltwater intrusion in the freshwater aquifer. We observed that the two dense water phases never completely mix during the simulation. Instead, a slice was continuously removed from the front of the polluted plume because of the discharge of freshwater. The observed mechanism is cyclical with a frequency compatible with the tide.
Expression of T‐cell receptor genes during early T‐cell development
Authors: Abbey Janice L , O'Neill Helen C
Published: October 2007

Lymphoid cell development is an ordered process that begins in the embryo in specific sites and progresses through multiple differentiative steps to production of T‐ and B‐cells. Lymphoid cell production is marked by the rearrangement process, which gives rise to mature cells expressing antigen‐specific T‐cell receptors (TCR) and immunoglobulins (Ig). While most transcripts arising from TCR or Ig loci reflect fully rearranged genes, germline transcripts have been identified, but these have always been thought to have no specific purpose. Germline transcription from either unrearranged TCR or unrearranged Ig loci was commonly associated with an open chromatin configuration during VDJ recombination. Since only early T and B cells undergo rearrangement, the association of germline transcription with the rearrangement process has served as an appropriate explanation for expression of these transcripts in early T‐ and B‐cell progenitors. However, germline TCR‐Vβ8.2 transcripts have now been identified in cells from RAG−/− mice, in the absence of the VDJ rearrangement event and recombinase activity. Recent data now suggest that germline TCR‐Vβ transcription is a developmentally regulated lymphoid cell phenomenon. Germline transcripts could also encode a protein that plays a functional role during lymphoid cell development. In the least, germline transcripts serve as markers of early lymphoid progenitors.
The reconnection of magnetic fields between plasmas with different densities: Scaling relations
Authors: Borovsky Joseph E. , Hesse Michael
Published: October 2007

Using two-dimensional compressible-magnetohydrodynamic computer simulations, the reconnection of magnetic fields between two plasmas with different mass densities is examined. Antiparallel, undriven merging is studied from a Harris-sheet initial condition with the sheet separating the two different plasmas. Reconnection is initiated with a resistive spot in the center of the Harris sheet. Density ratios from 1 to 320 are simulated. It is found that the rate of magnetic-field reconnection R is give approximately as R=0.07vAh, where vAh=B∕[4π(0.5ρ1+0.5ρ1)]1∕2 is a hybrid Alfvén speed constructed by averaging the densities of the two plasmas. In the symmetric-density case, plasma jetting speeds are equal to the local E̱×Ḇ velocity; in the asymmetric-density cases, the plasma jetting speeds exceed the local E̱×Ḇ velocity. In the asymmetric cases, plasma jetting tends to be parallel to the local magnetic field. In the symmetric-density case the plasma jetting arises from the site of the X-line and resides in the region of magnetic-field reversal; in the asymmetric case, jetting tends to reside in the lower-density plasma.
Effect of molecular packing on the exciton diffusion length in organic solar cells
Authors: Rim Seung-Bum , Fink Reinhold F. , Schöneboom Jan C. , Erk Peter , Peumans Peter
Published: October 2007

The efficiency of photocurrent generation in bilayer organic solar cells is shown to increase when molecular order is improved. This effect is studied in cells using pure cis and trans isomers of 3,4,9,10-perylene tetracarboxylic bisbenzimidazole. X-ray diffraction studies show that the π-π stacking direction lies in the substrate plane for both isomers and that the trans isomer exhibits improved molecular order in the out-of-plane direction. The improved stacking leads to an increased exciton diffusion length and increased external quantum and power conversion efficiencies. These results provide insight into the effect of molecular structure and packing on the exciton diffusion length.
Electronic structure of atomic Ti chains on semiconducting graphene nanoribbons: A first-principles study
Authors: Kan Er-Jun , Xiang H. J. , Yang Jinlong , Hou J. G.
Published: October 2007

The electronic and magnetic properties of one-dimensional titanium chains adsorbed on semiconducting armchair graphene nanoribbons (GNRs) are studied using the density functional theory. The results show that the strong hybridization between the titanium chain and the GNR gives rise to ferromagnetism and metallicity of the adsorption system. The electronic structure of the adsorption system is found to depend strongly on the width of the GNR. The adsorption system may offer half-metallic ferromagnetism when the width of GNR is less than 2.1nm, implying a new and promising way to realize GNR based spintronics.
Stability of alkali-encapsulating silicon cage clusters
Authors: Sporea C. , Rabilloud F.
Published: October 2007

We report a computational study of the possibility to form alkali-encapsulating Si clusters A@Sin with n=10–20. We predict and quantify the stability for lithium, sodium, and potassium atoms encapsulated in silicon cage. The structure and electronic properties are discussed. An electronic charge transfer from the alkali atom to the Sin cage is observed. The A@Sin cluster is formed of a positive charge located on the alkali surrounded by a negative one distributed on the whole Si cage. For each size the predicted stability of such structure is discussed and compared with that of surface-bound alkali isomers. The alkali-encapsulating Si clusters A@Sin are found to be stable but lying much higher in energy as compared to surface-bound alkali isomers.
Asymmetric charge patterning on surfaces and interfaces: Formation of hexagonal domains
Authors: Loverde Sharon M. , Olvera de la Cruz Monica
Published: October 2007

The structure of soft matter systems at interfaces is of utmost importance in the fields of nanopatterning and self-assembly. It has been shown that lamellar and hexagonal patterns can form on interfaces, for a wide variety of systems. The asphericity of charged domains is considered here for different strengths of the electrostatics, determined by the interface media, relative to the short range van der Waals interactions between the molecular components. The phase behavior of the surface structure is explored by using molecular dynamics simulations, including some dynamical aspects of the interaction between neighboring domains, using the Lindemann criterion [F. Lindemann, Z. Phys. 11, 609 (1910)]. The charge ratio of the electrostatic components influences the shape of the domains, as well as the degree of local order in the interdomain structure.
Propagation of axisymmetric Trivelpiece-Gould mode along vortex columns generated by diocotron instability
Authors: Kawai Y. , Kiwamoto Y. , Soga Y. , Aoki J.
Published: October 2007

A high-frequency (HF) oscillation has been observed to propagate along magnetic field lines with an axisymmetric profile extending over multiple columns of magnetized pure electron plasma which undergo two-dimensional vortex motions. The observed frequency is a few hundred times higher than the rotation frequency of the vortices and varies in time as the density distribution of electrons deforms from an unstable hollow profile into vortex columns and approaches a single-peaked distribution. Experimental examinations reveal that the HF oscillation is excited by the gate pulse applied to prepare the initial profile and that the oscillation does not influence the subsequent dynamics of vortex columns. Further examinations including detailed observations and theoretical analyses indicate that the HF oscillation represents a profile-dependent eigenfunction of the Trivelpiece-Gould mode wave that consists of a dominant axisymmetric component and small fractions of higher azimuthal modes associated with the density distribution separated into columns.
Linear response coupled cluster singles and doubles approach with modified spectral resolution of the similarity transformed Hamiltonian
Authors: Kowalski Karol , Hammond Jeff R. , de Jong Wibe A.
Published: October 2007

This paper discusses practical scheme for correcting the linear response coupled cluster with singles and doubles (CCSD) equations by shifting the poles corresponding to the equation-of-motion CCSD excitation energies by adding noniterative corrections due to triples. A simple criterion is derived for the excited states to be corrected in the spectral resolution of similarity transformed Hamiltonian on the CCSD level. Benchmark calculations were performed to compare the accuracies of static and dynamic polarizabilities obtained in this way with the CC3 and CCSDT counterparts.
Transient acoustic wave propagation in air-saturated porous media at low frequencies
Authors: Fellah Z. E. A. , Fellah M. , Mitri F. G. , Sebaa N. , Lauriks W. , Depollier C.
Published: October 2007

This paper provides a temporal model of the direct scattering problem for the propagation of transient low frequency waves in a homogeneous isotropic slab of porous material having a rigid frame. In this model, the inertial effects are described by the low frequency approximation of the tortuosity. The viscous and thermal losses of the medium are modeled by viscous and thermal permeabilities. The propagation equation is derived and solved analytically in the time domain. An original expression of Green’s function of the porous medium is obtained. The transmission scattering operator of the first transmitted wave is calculated and compared with experimental data.
Absorption of high-frequency guided waves in a plasma-loaded waveguide
Authors: Ganguli A. , Akhtar Kamran , Tarey R. D.
Published: October 2007

A kinetic theory model for the absorption of high-frequency guided plasma waves is presented for a warm, inhomogeneous, magnetized plasma column loaded inside a waveguide. Electron cyclotron resonance (ECR) absorption and Landau damping terms, derived as the anti-Hermitian part of the susceptibility tensor, are included in the model for a loss-free plasma-loaded waveguide developed earlier [A. Ganguli et al., Phys. Plasmas 5, 1178, (1998)]. In this formulation, the imaginary part of the complex propagation constant (in the presence of absorption) is obtained using a perturbation technique treating the anti-Hermitian part of the dielectric tensor as small in comparison to the Hermitian part, for the loss-free plasma. In this paper, we present the formulation for the inclusion of ECR absorption and Landau damping along with numerical results describing the role of a small population of warm electrons in wave damping in such a discharge. Numerical results are presented in the form of dispersion curves (plots of Vphase versus ω∕Ωe) and damping curves (plots of ∣Imkz∕kv∣ versus ω∕Ωe). It is seen that although the warm electrons have a marginal effect on wave dispersion, their presence produces a marked increase in the damping rates away from the ECR region. It is also shown that damping occurs primarily through Doppler-shifted ECR resonance and not Landau damping, even well away from ECR. Power absorption calculations are also presented for two magnetic field profiles.
Microwave band on-chip coil technique for single electron spin resonance in a quantum dot
Authors: Obata Toshiaki , Pioro-Ladrière Michel , Kubo Toshihiro , Yoshida Katsuharu , Tokura Yasuhiro , Tarucha Seigo
Published: October 2007

Microwave band on-chip microcoils are developed for the application to single electron spin resonance measurement with a single quantum dot. Basic properties such as characteristic impedance and electromagnetic field distribution are examined for various coil designs by means of experiment and simulation. The combined setup operates relevantly in the experiment at dilution temperature. The frequency responses of the return loss and Coulomb blockade current are examined. Capacitive coupling between a coil and a quantum dot causes photon assisted tunneling, whose signal can greatly overlap the electron spin resonance signal. To suppress the photon assisted tunneling effect, a technique for compensating for the microwave electric field is developed. Good performance of this technique is confirmed from measurement of Coulomb blockade oscillations.
Magnetic noise around metallic microstructures
Authors: Zhang Bo , Henkel C.
Published: October 2007

We compute the local spectrum of the magnetic field near a metallic microstructure at finite temperature. Our main focus is on deviations from a plane-layered geometry for which we review the main properties. Arbitrary geometries are handled with the help of numerical calculations based on surface integral equations. The magnetic noise shows a significant polarization anisotropy above flat wires with finite lateral width, in stark contrast to an infinitely wide wire. Within the limits of a two-dimensional setting, our results provide accurate estimates for loss and dephasing rates in so-called “atom chip traps” based on metallic wires. A simple approximation based on the incoherent summation of local current elements gives qualitative agreement with the numerics, but fails to describe current correlations among neighboring objects.
Au
∕
Li
F
/tris(8-hydroxyquinoline) aluminum interfaces
Authors: Ding Huanjun , Gao Yongli
Published: October 2007

The interface electronic structure of Au on LiF coated tris(8-hydroxyquinoline) aluminum (Alq) has been investigated using x-ray and ultraviolet photoemission spectroscopies. It is found that initial Au depositions introduce small shifts of energy levels toward higher binding energy, and subsequent Au depositions reverse the shifts. As the Au coverage increases, the energy level positions eventually reach those of the pristine Alq. The reversal is attributed to the p doping by Au that compensates for any possible Li release.
A high repetition rate time-of-flight electron energy analyzer
Authors: Hilbert S. A. , Barwick B. , Fabrikant M. , Uiterwaal C. J. G. J. , Batelaan H.
Published: October 2007

We demonstrate a time-of-flight electron energy analyzer that operates at an 80MHz repetition rate. The analyzer yields an energy resolution of 40meV for 3eV electrons. The energy resolution limit is dominated by the detector time (or temporal) resolution. With a currently available detector with a temporal resolution of 100ps, we predict an energy resolution of less than 1meV for 200meV electrons. This makes high repetition rate time-of-flight energy analyzers a promising low-technology alternative to current state-of-the-art techniques.
Efficient storage of hydrogen fuel into leaky cages of clathrate hydrate
Authors: Okuchi Takuo , Moudrakovski Igor L. , Ripmeester John. A.
Published: October 2007

We demonstrate an alternative principle to efficiently store molecular hydrogen fuel into clathrate hydrate medium. Hydrogen-free hydrate powders quickly absorb the hydrogen gas at moderate pressure appropriate for industrial applications. The absorption kinetics was observed in situ by nuclear magnetic resonance (NMR) spectroscopy in a pressurized tube. The diffusion of hydrogen through the solid hydrate medium was directly measured by pulsed field gradient NMR. At temperatures down to 250K, the stored hydrogen is still mobile so that the hydrate storage should work well even in cold environments.
The Sydney University Stellar Interferometer: A Major Upgrade to Spectral Coverage and Performance
Authors: Davis J. , Ireland M. J. , Chow J. , Jacob A. P. , Lucas R. E. , North J. R. , O'Byrne J. W. , Owens S. M. , Robertson J. G. , Seneta E. B. , Tango W. J. , Tuthill P. G.
Published: October 2007

A new beam-combination and detection system has been installed in the Sydney University Stellar Interferometer working at the red end of the visual spectrum (λλ 500–950 nm) to complement the existing blue-sensitive system (λλ 430–520 nm) and to provide an increase in sensitivity. Dichroic beam-splitters have been introduced to allow simultaneous observations with both spectral systems, albeit with some restriction on the spectral range of the longer wavelength system (λλ 550–760 nm). The blue system has been upgraded to allow remote selection of wavelength and spectral bandpass, and to enable simultaneous operation with the red system with the latter providing fringe-envelope tracking. The new system and upgrades are described and examples of commissioning tests presented. As an illustration of the improvement in performance the measurement of the angular diameter of the southern F supergiant δ CMa is described and compared with previous determinations.
Russian Minorities in the Former USSR
Authors: Actoṅ T. A.
Published: October 2007

In May 1992 an international conference examining the fate of minorities in the former Soviet Union was organized jointly by the Kennan Institute (DC) and Michigan State University. Fourteen speakers were invited from Moscow, St. Petersburgh, the north Caucasus, Ukraine, Uzbekistan, Moldova, and Lithuania; among them was Dr Ramazan Abdulatipov, Chairman of the Chamber of Nationalities of the Russian Parliament. The immediate impetus for the conference was a national survey of 6,500 Russians in 16 non-Russian regions of the former Soviet Union. The survey was conducted in August and September of 1991 by the Center of Public Opinion Studies in Moscow on the basis of a program prepared by Vladimir Shlapentokh and Lev Gudkov.
The Organization for Security and Co-operation in Europe Prepares to Act Against Anti-Gypsy Violence
Authors: Actoṅ T. A.
Published: October 2007

The Organization (Conference) on Security and Co-operation in Europe has just held a meeting in Budapest which was widely touted as a flop for its failure to achieve agreement on Bosnia. Its only reported action was to change its own name to “Organization for Security and Co-operation in Europe.” But, tucked away in the small print of the final document (paragraphs 25-6), is a resolution to appoint within the Office for Development of International Human Rights (OCJIHR) “a contact point for Roma and Sinti (Gypsy) issues.” This will act as a clearing-house for information, facilitate contacts between state and international and non-governmental organizations, working closely with Gypsy organizations. What this will mean in practice is not yet clear; but those who have pushed for this development have a clear agenda.
Language Politics in Independent Ukraine: Towards One or Two State Languages?
Authors: Arel Dominique
Published: October 2007

The implementation of language laws in multilingual territories often leads to acrimonious political conflicts, as demonstrated by the recent experiences of Quebec, Estonia, Moldova and Slovakia, to name but a few. The pattern of such conflicts is remarkably similar. First, one group (generally, but not necessarily, the demographic majority) claims ancestry on a territory which it considers its “homeland”; then it succeeds in proclaiming its language (the main marker of group identity) the sole official language in the “public domain” of the given territory. This action triggers organized protest from the other linguistic group (generally the demographic minority), which feels aggrieved over such fundamental issues as group status, equal opportunity for upward mobility, and educational rights.