bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoreflectance technique to measure thermal effusivity distribution with high spatial resolution
Authors: Hatori Kimihito , Taketoshi Naoyuki , Baba Tetsuya , Ohta Hiromichi
Published: November 2005

We have developed an apparatus to measure thermal effusivity distribution in solid materials with a high spatial resolution better than 10μm by the thermoreflectance technique and the periodic heating method. A metal film sputtered on the surface of a sample is periodically heated by a modulated laser beam. The temperature response is measured by using another thin laser beam as a thermoreflectance signal. The thermal effusivity of the sample is derived from the phase lag of the temperature response from the periodic heating. Measurements of a functionally graded material and a fiber composite material are presented as application examples of this thermal effusivity distribution measurement technique.
Ultrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz radiation
Authors: Laman N. , Bieler M. , van Driel H. M.
Published: November 2005

Shift and injection currents are generated in the wurtzite semiconductors CdSe and CdS at 295K using above-band-gap (ℏω>Eg) femtosecond pulses and detected via the emitted terahertz radiation; the optical beams are normally incident on samples with the optic axis in the plane of the surface. For optical intensities up to 75MWcm−2 (or carrier density <1018cm−3) the terahertz radiation amplitude shows the expected linear dependence and also varies with optical polarization and sample orientation consistent with the third-rank tensors that govern the current generation processes in the wurtzite structure. The largest shift currents are generated along the optical axis for light polarized along that axis. In CdSe with ℏω=1.80eV (690nm), the electron shift distance is ∼40% of the 0.25nm bond length and the peak current density is 5kAcm−2 for an optical intensity of 10MWcm−2; for CdS the corresponding experiment at ℏω=3.0eV (410nm) gives a shift distance ∼80% of the 0.26nm bond length with a peak current density of 50kAcm−2 for an incident intensity of 75MWcm−2. For injection current produced in CdSe with circularly polarized 690nm excitation, electrons are injected with an average speed of 9kms−1; this is ∼3% of the group velocity for electrons excited with the same energy. The corresponding values for CdS excited at 410nm are 20kms−1 and 2%. From the temporal characteristics of the terahertz emission for injection currents in CdS we deduce that the electron momentum scattering time is <100fs, consistent with mobility studies.
Dielectric response near the permittivity maximum in (Sr0.8Pb0.2)TiO3 ceramic solid solution
Authors: Somiya Yoshitaka , Bhalla Amar S. , Eric Cross L.
Published: November 2005

It is well known that the weak-field relative dielectric permittivity maximum ϵw(max) achieved at the paraelectric-ferroelectric phase transition in ceramic ferroelectric solid solutions in the perovskite structure family is a strong function of the processing conditions used in fabrications. Heretofore, the height and sharpness of the dielectric peak have often been regarded as good qualitative indicators of the quality and homogeneity of the solid solutions. In the SrTiO3–PbTiO3 solid solution system at low PbTiO3 concentrations, this sensitivity is again strongly evident. Now, however, even for samples with a very sharp ϵw(max) giving values >45000 at weak-field dielectric maximum temperature Tmax above the peak temperature, 1∕ϵw (ϵw: weak-field relative dielectric permittivity) departs from Curie-Weiss behavior more than 15°C above the Curie-Weiss temperature θ which now occurs above Tmax. The unusual condition Tmax<θ appears to occur for quite a wide range of processing conditions. Measurements of thermal contraction also show departure from linearity for more than 15°C above θ when measured over the same temperature range, suggesting the development of micro- or nanopolar regions as in a relaxor ferroelectric and this polar character has been confirmed by recent Raman spectroscopy. There is, however, no evidence of dielectric relaxation in the radio-frequency range as in the classic relaxors; however, earlier studies on similar compositions have shown strong dispersion in the gigahertz frequency range at temperatures near to but above Tmax. Preliminary studies of x-ray-diffraction linewidth also suggest that the highest permittivity peak samples are less homogenous, perhaps indicating that micropolarity may be associated with inhomogeneity in the lead cation distribution.
Three-dimensional simulation of void migration at the interface between thin metallic film and dielectric under electromigration
Authors: Zaporozhets T. V. , Gusak A. M. , Tu K. N. , Mhaisalkar S. G.
Published: November 2005

A kinetic Monte Carlo simulation of the electromigration-induced void migration behavior of three-dimensional nanovoids at the interface between a metal conductor and its dielectric overlayer is presented. Major stages of the recently observed failure mode of surface void migration and accumulation at the cathode via of Cu damascene interconnects were simulated, including the trapping at and detachment from grain boundaries (GBs) and GB triple junctions. The migration and shape evolution of voids along the interface and along the grain boundaries intersecting this interface have also been investigated in detail. The main results of the simulation correlate well with in situ observations as well as with simple analytical models of void trapping and detachment from GBs and their junctions.
Quantitative nuclear magnetic resonance measurements of preasymptotic dispersion in flow through porous media
Authors: Scheven U. M. , Verganelakis D. , Harris R. , Johns M. L. , Gladden L. F.
Published: November 2005

We use pulsed field gradient nuclear magnetic resonance to probe molecular displacements in preasymptotic Stokes flow through a pack of beads with bead diameter d=100±20μm, through a Bentheimer sandstone, and a Portland carbonate rock core, for a common range of flow velocities v and interrogation times Δ. For flow through the bead pack the length scale of the pore is well defined, as are the Peclet number Pe∊[20–80] and the Reynolds number Re<0.1. Probability distributions of molecular displacements P(ζ) are determined. The mean displacement ⟨ζ⟩, the variance σ2≡⟨(ζ−⟨ζ⟩)2⟩ and the skewness γ3≡⟨(ζ−⟨ζ⟩)3⟩ of P(ζ) are determined by a self-consistent cumulant analysis designed to minimize the systematic errors to which any cumulant analysis of non-Gaussian distributions is susceptible. Systematic errors in σ and γ arising from surface relaxation effects and flow displacements through the internal fields of rocks are quantified.
Schottky behavior at InN–GaN interface
Authors: Chen N. C. , Chang P. H. , Wang Y. N. , Peng H. C. , Lien W. C. , Shih C. F. , Chang Chin-An , Wu G. M.
Published: November 2005

In this work, GaN Schottky diodes were fabricated by depositing InN on GaN surfaces. The junction between these two materials exhibits strong rectifying behavior. The barrier heights were determined to be 1.25 eV, 1.06 eV, and 1.41 eV by current-voltage, current-voltage-temperature, and capacitance-voltage methods, respectively. These values exceed those of any other metal∕GaN Schottky barriers. Therefore, the conduction-band offset between InN and GaN should not be smaller than the barrier heights obtained here.
Composition and structure of Cu-based nanoicosahedral phase in Cu–Zr–Ti–Pd alloy
Authors: Louzguine-Luzgin D. V. , Inoue A. , Nagahama D. , Hono K.
Published: November 2005

The present work is devoted to an investigation of the composition of a nanoscale icosahedral phase in a Cu55Zr30Ti10Pd5 glassy alloy by three-dimensional atom probe analysis. The data indicate that the composition of the nanoicosahedral phase that precipitates from the Cu55Zr30Ti10Pd5 glassy alloy is not much different from that of the matrix, that is, the icosahedral phase is Cu-based containing more than 50at.% Cu. The formation criteria for Cu- and Zr∕Hf-based icosahedral phases are discussed based on quasi-lattice constant derived from average atomic diameter ratio.
Effects of ionization on the collisional streaming instability
Authors: Petrović D. , Vranjes J. , Poedts S.
Published: November 2005

The influence of inelastic collisions on the collisional streaming instability is studied. The dispersion equation of the system is derived in the regime of strongly magnetized electrons and magnetized ions. The linear stability of the system is investigated. The numerical results are applied to a laboratory argon plasma.
Energetic electrons and protons generated from the interaction of ultrashort laser pulses with microdroplet plasmas
Authors: Zheng Jun , Sheng Zheng-Ming , Peng Xiao-Yu , Zhang Jie
Published: November 2005

Generation of fast electrons and protons from ultrashort laser interactions with microdroplet plasmas has been simulated by two-dimensional particle-in-cell simulations. At weakly relativistic laser intensities, two jets of hot electrons are found to emit symmetrically in the backward direction when there is preplasma formed around the droplet surface. These electron jets are associated with resonance absorption around the target surface with a spherical geometry. At relativistic laser intensities, electron bunches generated by the laser ponderomotive force separated by a laser period are superimposed to the resonant hot-electron jets. Relevant with the hot-electron emission, energetic protons can be separated into two groups: one with higher energies mainly emits in certain angles within the laser polarization plane and another with lower energies emits nearly isotropically in all directions. The protons in the first group are accelerated by the electrostatic fields induced by the hot-electron jets due to the resonance absorption, while those in the second group are generated by the ambipolar expansion of the microdroplet plasma.
On the Rayleigh-Bénard problem in the continuum limit: Effects of temperature differences and model of interaction
Authors: Manela Avshalom , Frankel Itzchak
Published: November 2005

The transition to convection in the Rayleigh-Bénard problem at small Knudsen numbers is studied via a linear temporal stability analysis of the compressible “slip-flow” problem. Considering a power-law (variable hard-sphere) model of interaction our analysis indicates that for sufficiently large Froude numbers “softer” potentials result in less unstable systems. At small Froude numbers this trend is reversed, i.e., the “softer” interaction potentials correspond to a more unstable response. These results are discussed in terms of the opposing mechanisms of thermal expansion and compressibility. We carry out an asymptotic expansion for small temperature differences and establish the principle of exchange of stabilities for this limit. A singularity appears in this limit when compressibility effects are dominant.
Photodetectors based on treated CdSe quantum-dot films
Authors: Oertel David C. , Bawendi Moungi G. , Arango Alexi C. , Bulović Vladimir
Published: November 2005

We demonstrate photodetectors of sandwich geometry active in the visible spectrum in which the active layer is a 200 nm thick film of CdSe quantum dots (QDs). The solution-phase treatment of the QD film with n-butylamine after casting greatly increases the exciton dissociation efficiency and charge-transport properties of the film. Under 110mW∕cm2 illumination with light at λ=514nm, the photocurrent to dark current ratio, Iphoto∕Idark, is 103 at V=0V, and the 3 dB frequency is ∼50kHz. At room temperature, we observe zero-bias external quantum efficiencies (EQE) from 0.08% to 0.23% in the wavelength range λ=350nm to λ=575nm, corresponding to an internal quantum efficiency (IQE) of 0.6±0.1% across the tested spectrum. At V=−6V, EQE ranges from 15% to 24%, corresponding to an IQE of 70±10%.
Enhancement of the irreversible axial-strain limit of Y-Ba-Cu-O-coated conductors with the addition of a Cu layer
Authors: Cheggour N. , Ekin J. W. , Xie Y.-Y. , Selvamanickam V. , Thieme C. L. H. , Verebelyi D. T.
Published: November 2005

A Cu protection layer added to yttrium-barium-copper-oxide-(YBCO-) coated conductors substantially enhances the irreversible strain limit ϵirr for the onset of permanent electrical damage of the composite. This enhancement is of significance since it enables these conductors to meet the most severe strain requirements for applications such as electric generators. The conductors studied had either a Hastalloy-C substrate with an ion-beam-assisted deposition template or a rolling-assisted biaxially textured Ni-W substrate. The irreversible strain limit, obtained from critical-current measurements as a function of axial tensile strain at 76 K and self-field, increased from about 0.4% to more than 0.5% for both types of coated conductors with an added Cu layer, either by electroplating or lamination. This improvement is due only partially to the differential thermal contraction between Cu and the other conductor components. We believe that the Cu layer also enhances the fracture toughness of YBCO, thus acting as crack inhibiter/arrester.
Lithium-related states as deep electron traps in ZnO
Authors: Lopatiuk O. , Chernyak L. , Osinsky A. , Xie J. Q.
Published: November 2005

Carrier trapping in Li-doped ZnO was studied using Electron Beam Induced Current technique, as well as cathodoluminescence spectroscopy and persistent photoconductivity measurements. Under electron beam excitation, the minority carrier diffusion length underwent a significant increase, which was correlated with growing carrier lifetime, as demonstrated by the irradiation-induced decay of CL intensity of the near-band-edge transition. Variable-temperature cathodoluminescence and photoconductivity experiments showed evidence of carrier trapping and yielded activation energies of 280 and 245 meV, respectively. These observations are attributed to the presence of a deep, Li-related acceptor state.
Soft x-ray resonant reflectivity of low-Z material thin films
Authors: Wang Cheng , Araki T. , Ade H.
Published: November 2005

Soft x-ray resonant reflectivity, a method for low-Z materials that combines aspects of neutron reflectivity and x-ray reflectivity, is presented. Resonant reflectivity provides enhanced and selective sensitivity to specific chemical moieties near the absorption edges of constituent elements and was demonstrated through the characterization of a bilayer polymer thin film. The relative reflectivity of a particular interface could be tuned by adjusting the incident photon energy near the carbon 1s absorption edge. The resulting chemical specificity is analogous to using deuteration as a tracer or marker in neutron reflectivity, but without requiring special sample synthesis or preparation.
Fine structure of AlN∕AlGaN superlattice grown by pulsed atomic-layer epitaxy for dislocation filtering
Authors: Sun W. H. , Zhang J. P. , Yang J. W. , Maruska H. P. , Khan M. Asif , Liu R. , Ponce F. A.
Published: November 2005

We report the detailed structure analysis of our AlN∕AlGaN superlattice (SL) grown by pulsed atomic-layer epitaxy (PALE) for dislocation filtering. Due to the nature of PALE, the AlGaN well material itself in the SL was found to be composed actually of an AlxGa1−xN∕AlyGa1−yN short-period superlattice (SPSL), with the periodicity of 15.5Å (≈6 monolayer), determined consistently from high-resolution x-ray diffraction and high-resolution transmission electron microscopy measurements. The SPSL nature of the AlGaN layers is believed to benefit from the AlN∕AlGaN SL’s coherent growth, which is important in exerting compressive strain for the thick upper n-AlGaN film, which serves to eliminate cracks. Direct evidence is presented which indicates that this SL can dramatically reduce the screw-type threading dislocation density.
Electric-field stabilization in a high-density surface superlattice
Authors: Feil T. , Tranitz H.-P. , Reinwald M. , Wegscheider W.
Published: November 2005

By application of the cleaved-edge overgrowth technique, we realize a two-channel superlattice (SL) device. The structure combines the parallel transport through a low-density SL under almost homogeneous electric field conditions with that through a surface SL (SSL) with large carrier density, which is, without parallel transport, subject to pronounced field instabilities. Direct control of the SSL density allows a separation of both transport contributions. With parallel transport through the low-density SL, the current carried by the SSL is characteristic for a SL with homogeneous field distribution. In particular, it exhibits negative differential conductivity over a wide range of applied electric fields. In contrast, for current only through the SSL clear electric-field instabilities, typical for SLs at high densities are observed. Thus, by means of the parallel transport channel, field instabilities are avoided and transport in high-density SLs with a homogeneous field distribution becomes accessible.
Investigations on Underwater Fouling. I. The Role of Bacteria in the Early Stages of Fouling
Authors: Wood EJ Ferguson
Published: November 2005

Investigations of the biological factors involved in the fouling, by organisms, of objects immersed in sea-water have been commenced. It has been shown that algal spores, diatoms, and to a smaller extent, bacteria are concerned in initiating primary organic film formation on glass slides immersed in the sea at stations on the coast of New South Wales near Sydney.
Investigations on Underwater Fouling. III. Note on the Fouling Organisms attached to Naval Mines in North Queensland Waters
Authors: Allen FE
Published: November 2005

A study was made of organisms attached to six naval mines immersed for some years in north Queensland coastal waters. The most important groups represented were the mollusca, with ten species, corals, serpulids, bryozoa, and algae. By far the commonest organisms on all the mines examined were the molluscs Chama spp.
The Condition of the Fishery for Barracouta, Thyrsites atun (Euphrasen), in Australian Waters
Authors: Blackburn M
Published: November 2005

Barracouta is equal first with sea mullet in order of contribution by individual species to the Australian fish catch. The fishery is important only in Victoria and Tasmania, although the species is plentiful along the entire southern coast of Australia. From analysis of catch records, supported by observations on the fishery and the marketing situation, it is evident that there is no depletion. Variations in the Catch reflect principally the demand for the fish, which is usually below the catching capacity of the fishermen. At present the catch is being maintained at twice the pre-war level by a demand for fish for canning, largely for export. The influence of demand upon catch was remarkably shown in Tasmania during the war. There, in spite of opinions that the stocks were depleted, a four-fold increase in the annual catch was achieved, because of the demand and suitable control procedures. Barracouta was the only species in
Australia which made a substantial contribution to the war-time demand for more fish.
The Tasmanian Whitebait, Lovettia seali (Johnston), and the Whitebait Fishery
Authors: Blackburn M
Published: November 2005

The biology of the aplochitonid Lovettia seali (Johnston), which comprises over 95 per cent. of the Tasmanian whitebait catch, has been studied. Over 78,000 fish from 95 samples were sexed and measured, and 1,200 were classified as to maturity, pigmentation stages, and the presence or absence of food in the stomach. Vertebra counts were made for 1,200 specimens, and there were other observations upon smaller amounts of material. There are marked resemblances to other salmonoids in most points of the biology. There is conspicuous sexual dimorphism. The fish are anadromous and at their ascent are all mature or almost so, and all of the same age (one year by otoliths). After spawning begins there is progressive discoloration and emaciation, followed almost invariably by death. About 0.001 per cent. of the stock consists of two-year fish. The eggs are large compared with the size of fish (extremes of standard length in the adult stock are 33 and 70 mm.) and the incubation period is about three weeks. The larvae drift downstream to the sea. Sex ratio is highly variable, but generally the males greatly outnumber the females. A northern and a southern population can be distinguished, the differences being in growth rate and pigmentation. Each population supports a separate fishery, which operates on the ascending shoals. The history of the fisheries is outlined. The southern fishery has never been important because the fish available at the principal fishing locality are excessively pigmented. More suitable fish could be taken by operating further downstream, where the fish are typically at an earlier stage of maturity. The northern fishery has been vigorously prosecuted and overfishing was probably the cause of the decline in abundance of stock in 1947 and 1948. If there was overfishing, it operated purely by excessive removal of reproducers. The order of the optimum catch is empirically identified and a programme for the management of the stock, aiming at its rehabilitation, is recommended.
The Early Estimation of Percentage Fertilization in Trout Ova
Authors: Affleck RJ
Published: November 2005

Untreated, infertile trout ova may be readily distinguished from untreated, live, fertile ones after 24 hours. After examination the ova may be returned to the hatchery trays. By noting the number of infertile ova in a sample it is possible to estimate the percentage fertilization.
Parental Care of the Eggs and the Early Larvae of the Oyster Bleeny, Omobranchus anolius (Valenciennes) (Blenniidae)
Authors: Thomson JM , Bennett AE
Published: November 2005

The oyster blenny, Omobranchus anolius (Valenciennes), commonly uses the shells of the oyster Crassostrea commercialis (Ireland and Roughley) as a nesting place. The male parent guards the eggs during development. The eggs are laid in batches which hatch over a prolonged period. A daily rhythm in hatching is apparent, with most eggs hatching in the early evening. Some aspects of the development of the eggs and larvae are reported upon, particularly the formation and fate of the pigment patches. On hatching, each larva is taken into the mouth of the parent and expelled from the nest, apparently to remove from the larva an amorphous material which clings to it. Larvae were kept alive in the laboratory successfully for only 3 days after hatching.
Modified Whirling Apparatus for the Subsampling of Plankton
Authors: Kott P
Published: November 2005

An apparatus for the subsampling of plankton is described. It is shown that the samples obtained conform to the characteristics of a Poisson distribution. Limits to the efficiency of the apparatus are encountered when certain organisms with a tendency to clump together are present in high concentrations, but these limits are well within the accuracy required and achieved with the present methods of collecting plankton; otherwise the accuracy of the apparatus apparently does not vary with different types of organism.
HIV and increased risk of cardiovascular diseases
Authors: Das Satyajit
Published: November 2005

Highly active antiretroviral therapy (HAART) has significantly increased the survival rate of patients with HIV. However, abnormalities of lipid and insulin metabolism have been recognised and there is an increasing prevalence of fat redistribution, frank diabetes and hyperlipidaemia in HIV-infected patients receiving HAART. Several observational studies have described associations between HIV infection, HAART and cardiovascular disease. The management of risk factors for cardiovascular disease is expected to play an important role in the treatment of HIV infection.
Diffusion-limited phase separation in eukaryotic chemotaxis
Authors: Gamba Andrea , de Candia Antonio , Di Talia Stefano , Coniglio Antonio , Bussolino Federico , Serini Guido
Published: November 2005

The ability of cells to sense spatial gradients of chemoattractant factors governs the development of complex eukaryotic organisms. Cells exposed to shallow chemoattractant gradients respond with strong accumulation of the enzyme phosphatidylinositol 3-kinase (PI3K) and its D3-phosphoinositide product (PIP3) on the plasma membrane side exposed to the highest chemoattractant concentration, whereas PIP3-degrading enzyme PTEN and its product PIP2localize in a complementary pattern. Such an early symmetry-breaking event is a mandatory step for directed cell movement elicited by chemoattractants, but its physical origin is still mysterious. Here, we propose that directional sensing is the consequence of a phase-ordering process mediated by phosphoinositide diffusion and driven by the distribution of chemotactic signal. By studying a realistic reaction–diffusion lattice model that describes PI3K and PTEN enzymatic activity, recruitment to the plasma membrane, and diffusion of their phosphoinositide products, we show that the effective enzyme–enzyme interaction induced by catalysis and diffusion introduces an instability of the system toward phase separation for realistic values of physical parameters. In this framework, large reversible amplification of shallow chemotactic gradients, selective localization of chemical factors, macroscopic response timescales, and spontaneous polarization arise naturally. The model is robust with respect to order-of-magnitude variations of the parameters.
Toll-like receptor 3 ligand attenuates LPS-induced liver injury by down-regulation of toll-like receptor 4 expression on macrophages
Authors: Jiang Wei , Sun Rui , Wei Haiming , Tian Zhigang
Published: November 2005

This study demonstrates that pretreatment with polyinosinic-polycytidylic acid (poly I:C) significantly decreased the mortality and liver injury caused by injection of lipopolysaccharide (LPS) in the presence ofd-galactosamine (d-GalN) in C57BL/6 mice. Depletion of natural killer, natural killer T, and T cells did not change the protective effect of poly I:C on LPS/d-GalN-induced liver injuryin vivo. However, depletion of macrophages abolished LPS/d-GalN-induced fulminant hepatitis, which could be restored by adoptive transfer of macrophages but not by transfer of poly I:C-treated macrophages. Treatment with poly I:C down-regulated the expression of the toll-like receptor 4 (TLR4) on macrophages and reduced the sensitivity of macrophages (Kupffer cells and peritoneal macrophages from C57BL/6 mice, or RAW264.7 cells) to LPS stimulation. Poly I:C pretreatment also impaired the signaling of mitogen-activated protein kinases and NF-κB induced by LPS in RAW264.7 cells. Blockade of TLR3 with a TLR3 antibody abolished poly I:C down-regulation of TLR4 expression and LPS stimulation of TNF-α production in RAW264.7 cells. Taken together, our findings suggest that activation of TLR3 by its ligand, poly I:C, induced LPS tolerance by down-regulation of TLR4 expression on macrophages.
The genome sequence ofClostridium botulinumtype C neurotoxin-converting phage and the molecular mechanisms of unstable lysogeny
Authors: Sakaguchi Yoshihiko , Hayashi Tetsuya , Kurokawa Ken , Nakayama Keisuke , Oshima Kenshiro , Fujinaga Yukako , Ohnishi Makoto , Ohtsubo Eiichi , Hattori Masahira , Oguma Keiji
Published: November 2005

Botulinum neurotoxins (BoNTXs) produced byClostridium botulinumare among the most poisonous substances known. Of the seven types of BoNTXs, genes for type C1 and D toxins (BoNTX/C1 and D) are carried by bacteriophages. The gene for exoenzyme C3 also resides on these phages. Here, we present the complete genome sequence of c-st, a representative of BoNTX/C1-converting phages. The genome is a linear double-stranded DNA of 185,682 bp with 404-bp terminal direct repeats, the largest known temperate phage genome. We identified 198 potential protein-coding regions, including the genes for production of BoNTX/C1 and exoenzyme C3. Very exceptionally, as a viable bacteriophage, a number of insertion sequences were found on the c-st genome. By analyzing the molecular structure of the c-st genome in lysogens, we also found that it exists as a circular plasmid prophage. These features account for the unstable lysogeny of BoNTX phages, which has historically been called “pseudolysogeny.” The PCR scanning analysis of other BoNTX/C1 and D phages based on the c-st sequence further revealed that BoNTX phages comprise a divergent phage family, probably generated by exchanging genomic segments among BoNTX phages and their relatives.
The epithelial Ca
2+
channel TRPV5 is essential for proper osteoclastic bone resorption
Authors: van der Eerden Bram C. J. , Hoenderop Joost G. J. , de Vries Teun J. , Schoenmaker Ton , Buurman Cok J. , Uitterlinden André G. , Pols Huibert A. P. , Bindels René J. M. , van Leeuwen Johannes P. T. M.
Published: November 2005

Bone remodeling involves the interplay of bone resorption and formation and is accurately controlled to maintain bone mass. Both processes require transcellular Ca
2+
transport, but the molecular mechanisms engaged remain largely elusive. The epithelial Ca
2+
channel TRPV5 is one of the most Ca
2+
-selective transient receptor potential (TRP) channels. In this study, the functional role of TRPV5 in bone was investigated. TRPV5 mRNA was expressed in human and murine bone samples and in osteoclasts along with other genes involved in transcellular Ca
2+
transport, including calbindin-D
9K
and calbindin-D
28K
, Na
+
/Ca
2+
exchanger 1, and plasma membrane Ca
2+
-ATPase 1b. TRPV5 expression in murine osteoclasts was confirmed by immunostaining and showed predominant localization to the ruffled border membrane. However, TRPV5 was absent in osteoblasts. Analyses of femoral bone sections from TRPV5 knockout (TRPV5
-/-
) mice revealed increased osteoclast numbers and osteoclast area, whereas the urinary bone resorption marker deoxypyridinoline was reduced compared with WT (TRPV5
+/+
) mice. In an
in vitro
bone marrow culture system, the amount of osteoclasts and number of nuclei per osteoclast were significantly elevated in TRPV5
-/-
compared with TRPV5
+/+
mice. However, using a functional resorption pit assay, we found that bone resorption was nearly absent in osteoclast cultures from TRPV5
-/-
mice, supporting the impaired resorption observed
in vivo
. In conclusion, TRPV5 deficiency leads to an increase in osteoclast size and number, in which Ca
2+
resorption is nonfunctional. This report identifies TRPV5 as an epithelial Ca
2+
channel that is essential for osteoclastic bone resorption and demonstrates the significance of transcellular Ca
2+
transport in osteoclastic function.
Cooperative cargo transport by several molecular motors
Authors: Klumpp Stefan , Lipowsky Reinhard
Published: November 2005

The transport of cargo particles that are pulled by several molecular motors in a cooperative manner is studied theoretically in this article. The transport properties depend primarily on the maximal number
N
of motor molecules that may pull simultaneously on the cargo particle. Because each motor must unbind from the filament after a finite number of steps but can also rebind to it again, the actual number of pulling motors is not constant but varies with time between zero and
N
. An increase in the maximal number
N
leads to a strong increase of the average walking distance (or run length) of the cargo particle. If the cargo is pulled by up to
N
kinesin motors, for example, the walking distance is estimated to be 5

N
–1

/
N
micrometers, which implies that seven or eight kinesin molecules are sufficient to attain an average walking distance in the centimeter range. If the cargo particle is pulled against an external load force, this force is shared between the motors, which provides a nontrivial motor–motor coupling and a generic mechanism for nonlinear force–velocity relationships. With increasing load force, the probability distribution of the instantaneous velocity is shifted toward smaller values, becomes broader, and develops several peaks. Our theory is consistent with available experimental data and makes quantitative predictions that are accessible to systematic
in vitro
experiments.
Influences of parents' education on their children's educational attainments: the role of parent and child perceptions
Authors: Eccles Jacquelynne S.
Published: November 2005

This paper is based on a talk given at the conference of the Centre for Research on the Wider Benefits of Learning, September 2004. There is consistent evidence that parents' education predicts children's educational outcomes, alongside other distal family characteristics such as family
income, parents' occupations and residence location. A variety of explanations have been offered for these associations. In this paper, we review the most prominent explanations, present a comprehensive model of the influences of parents' education and then summarize some of the research we
have done that focuses on the role of parental influences on children's academic achievement.
Education, learned effectiveness and health
Authors: Mirowsky John , Ross Catherine E.
Published: November 2005

Education forms a unique dimension of social status with qualities that make it especially important to health. Educational attainment marks social status at the beginning of adulthood, functioning as the main bridge between the status of one generation and the next, and also as the
main avenue of upward mobility. It precedes the other achieved social statuses and substantially influences them, including occupation and occupational status, earnings, personal and household income and wealth, and freedom from economic hardship. Education creates desirable outcomes because
it trains individuals to acquire, evaluate and use information. It teaches individuals to tap the power of knowledge. As a result, education influences health in ways that are varied, present at all stages of adult life, cumulative, self-amplifying and uniformly positive. Education develops
the learned effectiveness that enables self-direction toward any and all values sought, including health.
Identity capital, social capital and the wider benefits of learning: generating resources facilitative of social cohesion
Authors: Côté James E.
Published: November 2005

This paper reviews theory and research pertaining to the acquisition of identity capital and social capital, and applies it to the changing nature of learning in late-modern societies, where the ability to undertake individualized life courses is becoming an increasingly important divide
in the fortunes of the young as they make their way to adulthood. The identity capital model is elaborated in terms of the importance now placed on choice-making in managing the individualization process and balancing the immediate appeal of default individualization with the long-term gains
of developmental individualization. This model points toward the need to institute an 'education for choice' in curricula to enhance the wider benefits of learning for both the individual, in terms of identity capital accumulation, and for the community with respect to intergenerational social
capital building.
Effects of mothers' education on parenting: an investigation across three generations
Authors: Duckworth Kathryn , Sabates Ricardo
Published: November 2005

The paper investigates the relationship between mother's education and her parenting using data from the child supplement of the 1958 National Child Development Study (NCDS). By considering data across generations, our dataset allows us to estimate the size of the bias in the relationship
between education and parenting from failing to account for background characteristics, early cognitive development and mother's own parenting experiences. The subjects were 1,182 longitudinally sampled mothers of 1,879 children aged between 3 and 18 years old and divided approximately equally
across gender (51% sons, 49% daughters). Controlling for a wide range of family background variables and mother's own achievement prior to 16, results indicate a confounding bias of 73% for cognitive stimulation and 89% for emotional support. This confounding bias is larger for daughters than
for sons. Even after the inclusion of a large set of controls, a small effect of maternal education on parenting, assessed in terms of the provision of a cognitively stimulating environment, remains statistically significant but only for sons. Although educational effects estimated here suffer
from downwards bias owing to under-representation of older mothers within the data, some unobserved factors could remain as a source of bias.
The effects of adult learning on self-efficacy
Authors: Hammond Cathie , Feinstein Leon
Published: November 2005

We use quantitative and qualitative methods to investigate the links between participation in adult learning and self-efficacy, particularly for the subgroup of adults who had low levels of achievement at school. We focus on self-efficacy because it translates into a range of wider
benefits and because it may afford protection from depression and other forms of social exclusion. Quantitative analyses of data from the National Child Development Study (NCDS) provide evidence for an association between taking courses and transformations in self-efficacy for all cohort members,
but the association is greatest and the evidence is strongest for our subgroup. A related fieldwork project involving in depth interviews with 15 women with poor school attainment sampled from the NCDS provides insights into some of the processes that underlie the associations found: (i) perceptions
of achievement in adult education increase self-efficacy; (ii) adult education leads to more challenging occupations, which build self-efficacy; (iii) resistance to participation in adult education is reduced as self-efficacy increases; and (iv) learning on the job can build self-efficacy,
and although participation in employer-provided training courses does not appear to play an important role, it reflects engagement in occupations where the value of learning is recognized. The interviews also illustrate how school impacts on self-efficacy and motivation to learn throughout
the life course, and how important background and life circumstances can be in shaping the impacts of adult learning on self-efficacy.
Can adult education change extremist attitudes?
Authors: Preston John , Feinstein Leon , Anderson T. Marion
Published: November 2005

Although adult education leads to a moderation of racist or authoritarian attitudes amongst the general population, little is known concerning the impact of adult education on individuals with extremist racist–authoritarian views. In this paper we group individuals from the NCDS
(National Child Development Study) into various racist–authoritarian categories at ages 33 and 42 using cluster analysis. Following this identification we test various hypothesis concerning the relationship between adult education and attitude change. In particular, questioning whether
adult education can transform attitudes amongst those with racist–authoritarian attitudes and/or whether adult education can sustain non-extremist views. Although there is evidence of a conditional association between adult education and sustaining non-extremist views we are sceptical
concerning the ability of adult education to change extremist positions. We conclude that further work on the mechanisms linking education and extremist attitudes is required if we are to identify causal processes.
The cell cycle–apoptosis connection revisited in the adult brain
Authors: Bauer Sylvian , Patterson Paul H.
Published: November 2005

Adult neurogenesis is studied in vivo using thymidine analogues such as bromodeoxyuridine (BrdU) to label DNA synthesis during the S phase of the cell cycle. However, BrdU may also label DNA synthesis events not directly related to cell proliferation, such as DNA repair and/or abortive reentry into the cell cycle, which can occur as part of an apoptotic process in postmitotic neurons. In this study, we used three well-characterized models of injury-induced neuronal apoptosis and the combined visualization of cell birth (BrdU labeling) and death (Tdt-mediated dUTP-biotin nick end labeling) to investigate the specificity of BrdU incorporation in the adult mouse brain in vivo. We present evidence that BrdU is not significantly incorporated during DNA repair and that labeling is not detected in vulnerable or dying postmitotic neurons, even when a high dose of BrdU is directly infused into the brain. These findings have important implications for a controversy surrounding adult neurogenesis: the connection between cell cycle reactivation and apoptosis of terminally differentiated neurons.
On the non-starlikeness of solutions to the starlike interior wake problem
Authors: Acker Andrew
Published: November 2005

We study examples of the starlike interior “wake problem" for which no starlike solution exists relative to the natural star center of the problem. These examples show that the main result of D.E. Tepper in “A mathematical model for a wake” (Michigan Math. J. 31 (1984), 161–165) is not correct.
Poisson geometry of differential invariants of curves in some nonsemisimple homogeneous spaces
Authors: Beffa G.
Published: November 2005

In this paper we describe a family of compatible Poisson structures defined on the space of coframes (or differential invariants) of curves in flat homogeneous spaces of the form

M

≅
(
G
⋉

R

n

)

/

G

\mathcal {M} \cong (G\ltimes \mathbb {R}^n)/G

where

G
⊂

G
L

(
n
,

R

)

G\subset {\mathrm {GL}}(n,\mathbb {R})

is semisimple. This includes Euclidean, affine, special affine, Lorentz, and symplectic geometries. We also give conditions on geometric evolutions of curves in the manifold

M

\mathcal {M}

so that the induced evolution on their differential invariants is Hamiltonian with respect to our main Hamiltonian bracket.
The Gelfand-Kirillov dimension of quadratic algebras satisfying the cyclic condition
Authors: Cedó Ferran , Jespers Eric , Okniński Jan
Published: November 2005

We consider algebras over a field

K
K

presented by generators

x
1

,
…
,

x_1,\dots ,

x
n

x_n

and subject to

(

n
2

)

n\choose 2

square-free relations of the form

x

i

x

j

=

x

k

x

l

x_{i}x_{j}=x_{k}x_{l}

with every monomial

x

i

x

j

,
i
≠
j

x_{i}x_{j}, i\neq j

, appearing in one of the relations. It is shown that for

n
>
1

n>1

the Gelfand-Kirillov dimension of such an algebra is at least two if the algebra satisfies the so-called cyclic condition. It is known that this dimension is an integer not exceeding

n
n

. For

n
≥
4

n\geq 4

, we construct a family of examples of Gelfand-Kirillov dimension two. We prove that an algebra with the cyclic condition with generators

x
1

,
…
,

x
n

x_1,\dots ,x_n

has Gelfand-Kirillov dimension

n
n

if and only if it is of

I
I

-type, and this occurs if and only if the multiplicative submonoid generated by

x
1

,
…
,

x
n

x_1,\dots ,x_n

is cancellative.
Projections in operator ranges
Authors: Corach Gustavo , Maestripieri Alejandra , Stojanoff Demetrio
Published: November 2005

If

H

\mathcal {H}

is a Hilbert space,

A
A

is a positive bounded linear operator on

H

\mathcal {H}

and

S

\mathcal {S}

is a closed subspace of

H

\mathcal {H}

, the relative position between

S

\mathcal {S}

and

A

−
1

(

S

⊥

)

A^{-1}(\mathcal {S}^\perp )

establishes a notion of compatibility. We show that the compatibility of

(
A
,

S

)

(A,\mathcal {S})

is equivalent to the existence of a convenient orthogonal projection in the operator range

R
(

A

1

/

2

)

R(A^{1/2})

with its canonical Hilbertian structure.
An observation on realcompact spaces
Authors: Ercan Z.
Published: November 2005

We give a characterization of realcompact spaces in terms of nets. By using the technique of this characterization we give easy proofs of the Tychonoff Theorem and the Alaoglu Theorem.
Classification of tight contact structures on small Seifert 3–manifolds with 𝑒₀≥0
Authors: Ghiggini Paolo , Lisca Paolo , Stipsicz András
Published: November 2005

We classify positive, tight contact structures on closed Seifert fibered 3–manifolds with base

S
2

S^2

, three singular fibers and

e
0

≥
0

e_0\geq 0

.
Joint measurability and the one-way Fubini property for a continuum of independent random variables
Authors: Hammond Peter , Sun Yeneng
Published: November 2005

As is well known, a continuous parameter process with mutually independent random variables is not jointly measurable in the usual sense. This paper proposes an extension of the usual product measure-theoretic framework, using a natural “one-way Fubini” property. When the random variables are independent even in a very weak sense, this property guarantees joint measurability and defines a unique measure on a suitable minimal

σ
\sigma

-algebra. However, a further extension to satisfy the usual (two-way) Fubini property, as in the case of Loeb product measures, may not be possible in general. Some applications are also given.
On Bernstein type theorems in Finsler spaces with the volume form induced from the projective sphere bundle
Authors: He Qun , Shen Yi-Bing
Published: November 2005

By using the volume form induced from the projective sphere bundle of the Finsler manifold, we study the Finsler minimal submanifolds. It is proved that such a volume form for the Randers metric

F
=
α
+
β

F=\alpha +\beta

in a Randers space is just that for the Riemannian metric

α
\alpha

, and therefore the Bernstein type theorem in the special Randers space of dimension

≤
8

\leq 8

is true. Moreover, a Bernstein type theorem in the

3
3

-dimensional Minkowski space is established by considering the volume form induced from the projective sphere bundle.
Optimal Weyl inequality in Banach spaces
Authors: Hinrichs Aicke
Published: November 2005

A well-known multiplicative Weyl inequality states that the sequence of eigenvalues

(

λ
k

(
T
)
)

(\lambda _k(T))

and the sequence of approximation numbers

(

a
k

(
T
)
)

(a_k(T))

of any compact operator

T
T

in a Banach space satisfy
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="product Underscript k equals 1 Overscript n Endscripts StartAbsoluteValue lamda Subscript k Baseline left-parenthesis upper T right-parenthesis EndAbsoluteValue less-than-or-equal-to n Superscript n slash 2 Baseline product Underscript k equals 1 Overscript n Endscripts a Subscript k Baseline left-parenthesis upper T right-parenthesis">

∏

k
=
1

n

|

λ
k

(
T
)

|

≤

n

n

/

2

∏

k
=
1

n

a
k

(
T
)

\prod _{k=1}^n |\lambda _k(T)| \le n^{n/2} \prod _{k=1}^n a_k(T)

\]
for all

n
n

. We prove here that the constant

n

n

/

2

n^{n/2}

is optimal, which solves a longstanding problem.
𝑜-bounded groups and other topological groups with strong combinatorial properties
Authors: Tsaban Boaz
Published: November 2005

We construct several topological groups with very strong combinatorial properties. In particular, we give simple examples of subgroups of

R

\mathbb {R}

(thus strictly

o
o

-bounded) which have the Menger and Hurewicz properties but are not

σ
\sigma

-compact, and show that the product of two

o
o

-bounded subgroups of

R

N

\mathbb {R}^{\mathbb {N}}

may fail to be

o
o

-bounded, even when they satisfy the stronger property

S

1

(

B

Ω

,

B

Ω

)

\mathsf {S}_1(\mathcal {B}_{\Omega },\mathcal {B}_{\Omega })

. This solves a problem of Tkačenko and Hernandez, and extends independent solutions of Krawczyk and Michalewski and of Banakh, Nickolas, and Sanchis. We also construct separable metrizable groups

G
G

of size continuum such that every countable Borel

ω
\omega

-cover of

G
G

contains a

γ
\gamma

-cover of

G
G

.
From gas dynamics to pressureless gas dynamics
Authors: Coulombel Jean-François
Published: November 2005

This paper is devoted to the convergence of solutions of the compressible Euler equations towards solutions of the pressureless gas dynamics system, when the pressure tends to

0
0

. The goal is to prove accurate uniform bounds for particular solutions of the Euler equations.