bluuebunny/crossref_metadata_2025 huggingface dataset:
Verbal and nonverbal predictors of early language problems: an analysis of twins in early childhood back to infancy
Authors: OLIVER BONAMY , DALE PHILIP S. , PLOMIN ROBERT
Published: November 2004

We investigated infant precursors of low language scores in early childhood. The sample included 373 probands in 130 monozygotic (MZ) and 109 same-sex dizygotic (DZ) twin pairs in which at least one member of the pair scored in the lowest 15th percentile of a control sample on a general language factor derived from tester-administered tests at 4;6. From data at 2;0, 3;0 and 4;0 the antecedents of poor language performance at 4;6 for these probands were compared to 290 control children. As early as 2;0, language measures substantially predicted low-language status at 4;6, with predictions increasing at 3;0 and 4;0. Nonverbal cognitive development at 3;0 and 4;0 was nearly as predictive of low language at 4;6 as were the language measures. Behaviour problems were also significant predictors of low language status although the associations were only about half as strong. Bivariate genetic analyses indicated that these predictions are mediated by both genetic and shared environmental links.
Discussing those not present: comprehension of references to absent caregivers
Authors: SAYLOR MEGAN M. , BALDWIN DARE A.
Published: November 2004

The ability to understand references to the absent enables conversation to move beyond the here-and-now to matters distant in both space and time. Such understanding requires appreciating the relation between language and communicative intent: one must recognize speakers' intentions to use language to converge on a shared conversational focus that is at least somewhat independent of the current context. Despite its centrality to language development, the emergence of absent reference understanding has received little systematic attention. The present research investigated the responses of 60 infants aged 1;0 to 2;6 to a researcher talking about both present and absent caregivers. When infants aged 1;3 and older heard talk about absent caregivers they displayed a complex of nonverbal communicative responses that were divergent from their responses to talk about a present person. Infants aged 2;0 and older provided responses indicating understanding of absent reference. The findings suggest that by 1;3 infants may have at least a tacit appreciation of language as a device for coordinating conversational focus, and hint at increased sophistication in infants' absent reference comprehension skills at 2;0.
Speeded production of inflected words in children and adults
Authors: CLAHSEN HARALD , HADLER MEIKE , WEYERTS HELGA
Published: November 2004

This study examines the production of regular and irregular participle forms of German with high and low frequencies using a speeded production task. 40 children in two age groups (five- to seven-year olds, eleven- to twelve-year olds) and 35 adult native speakers of German listened to stem forms of verbs presented in a sentential context and were asked to produce corresponding participle forms as quickly and accurately as possible. Dependent variables were the subjects' participle-production latencies and error rates. We found contrasts between the production of regular and irregular forms in both children and adults, with respect to the production latencies and types of morphological error. Children overapplied the regular patterns to forms that are irregular in the adult language, but not vice versa. High-frequency irregular participles were produced faster (and amongst the children more accurately) than low-frequency ones, whereas regular participles yielded a reverse frequency effect, i.e. longer production latencies for high-frequency forms than for low-frequency ones, in the two groups of children as well as in one subgroup of adults. We explain these findings from the perspective of dual-mechanism models of inflection arguing that the mental mechanisms and representations for processing morphologically complex words (‘words’ and ‘rules’) are the same in children and adults, and that the observed child/adult differences in participle production are due to slower and less accurate lexical access in children than in adults.
Economic value of safe water for the infrastructurally disadvantaged urban household: A case study in Delhi, India
Authors: Dasgupta Purnamita , Dasgupta Rajib
Published: November 2004

Delhi has witnessed rapid urbanization during the past 50 years, with ever increasing growth in population and economic activity leading to water stress in several parts of the city. This paper looks at the valuation of water as an economic resource in the context of a low‐income, infrastructurally disadvantaged urban household, through the results of a primary survey. In doing so, it examines several issues, often interlinked, concerning the quality and quantity of water being “accessed” by households. While there is no one perfect way of estimating household demand for improved water services, the study uses the contingent valuation approach and evaluates the findings in terms of the health benefits from safe water and the costs of provision of safe supplies.
Solar heating by the near‐IR CO2 bands in the mesosphere
Authors: Fomichev V. I. , Ogibalov V. P. , Beagley S. R.
Published: November 2004

Absorption of solar energy by the near‐infrared (NIR) CO2 bands provides an important source of heating in the mesosphere. At 60–85 km, this source exceeds 1 K day−1 and contributes up to 30% of the total solar heating. Calculation of the solar heating in the NIR CO2 bands requires consideration of complex non‐local thermodynamic equilibrium (non‐LTE) processes. The small energy effect, narrow region of importance, and the necessity to consider non‐LTE effects, have accounted for the absence of an adequate parameterization for the NIR CO2 bands. Recently a parameterization has been developed and implemented into the Canadian Middle Atmosphere Model. Numerical experiments with this model have shown that inclusion of the NIR CO2 heating results in a significant warming of up to 8 K in the mesosphere for the current CO2 amount but does not significantly change the model thermal response induced by the doubling of CO2.
Sea state monitoring using coastal GNSS‐R
Authors: Soulat F. , Caparrini M. , Germain O. , Lopez‐Dekker P. , Taani M. , Ruffini G.
Published: November 2004

We report on a coastal experiment to study GPS L1 reflections. The campaign was carried out at the Barcelona Port breaker and dedicated to the development of sea‐state retrieval algorithms. An experimental system built for this purpose collected and processed GPS data to automatically generate a times series of the interferometric complex field (ICF). The ICF was analyzed off line and compared to a simple developed model that relates ICF coherence time to the ratio of significant wave height (SWH) and mean wave period (MWP). The analysis using this model showed good consistency between the ICF coherence time and nearby oceanographic buoy data. Based on this result, preliminary conclusions are drawn on the potential of coastal GNSS‐R for sea state monitoring using semi‐empirical modeling to relate GNSS‐R ICF coherence time to SWH.
Application of near real‐time radial semblance to locate the shallow magmatic conduit at Kilauea Volcano, Hawaii
Authors: Dawson P. , Whilldin D. , Chouet B.
Published: November 2004

Radial Semblance is applied to broadband seismic network data to provide source locations of Very‐Long‐Period (VLP) seismic energy in near real time. With an efficient algorithm and adequate network coverage, accurate source locations of VLP energy are derived to quickly locate the shallow magmatic conduit system at Kilauea Volcano, Hawaii. During a restart in magma flow following a brief pause in the current eruption, the shallow magmatic conduit is pressurized, resulting in elastic radiation from various parts of the conduit system. A steeply dipping distribution of VLP hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the Halemaumau Pit Crater. The distinct hypocenters suggest the shallow plumbing system beneath Halemaumau consists of a complex plexus of sills and dikes. An unconstrained location for a section of the conduit is also observed beneath the region between Kilauea Caldera and Kilauea Iki Crater.
Role of solar wind dynamic pressure in driving ionospheric Joule heating
Authors: Palmroth M. , Pulkkinen T. I. , Janhunen P. , McComas D. J. , Smith C. W. , Koskinen H. E. J.
Published: November 2004

We investigate the role of the solar wind dynamic pressure on the ionospheric dynamics both observationally and using a global MHD simulation. Using ACE solar wind observations we carry out a statistical superposed epoch analysis, in which we determine the ionospheric response, as characterized by the AE index, to solar wind pressure pulses identified from the ACE solar wind data. We find that under steady southward interplanetary magnetic field the AE index increases 35% in 20 min following the pressure pulse but that no such reaction is observed under steady northward IMF. Second, we determine the ionospheric Joule heating in several events using a global MHD simulation GUMICS‐4. We find that the solar wind dynamic pressure and the Joule heating are positively correlated. Finally, we discuss mechanisms linking the dynamic pressure to Joule heating. We find evidence that in the simulation, increasing dynamic pressure increases field‐aligned currents, which then increases ionospheric Joule heating.
N budgets and aquatic uptake in the Ipswich River basin, northeastern Massachusetts
Authors: Williams Michael , Hopkinson Charles , Rastetter Edward , Vallino Joseph
Published: November 2004

We calculated N budgets and conducted nutrient uptake experiments to evaluate the fate of N in the aquatic environment of the Ipswich River basin, northeastern Massachusetts. A mass balance indicates that the basin retains about 50% of gross N inputs, mostly in terrestrial components of the landscape, and the loss and retention of total nitrogen (TN) in the aquatic environment was about 9% of stream loading. Uptake lengths of PO4 and NH4 were measurable in headwater streams, but NO3 uptake was below detection (minimum detection limit = 0.05 μM). Retention or loss of NO3 was observed in a main stem reach bordered by wetland habitat. Nitrate removal in urban headwater tributaries was because of water withdrawals and denitrification during hypoxic events and in ponded wetlands with long water residence times. A mass balance using an entire river network indicates that basin‐wide losses due to aquatic denitrification are considerably lower than estimates from several recent studies and range from 4 to 16% of TDN in stream loading. Withdrawals for domestic use restrict the runoff of headwater catchments from reaching the main stem during low base flow periods, thereby contributing to the spatial and temporal regulation of N export from headwater tributaries.
Entiat Experimental Forest: Catchment‐scale runoff data before and after a 1970 wildfire
Authors: Woodsmith Richard D. , Vache Kellie B. , McDonnell Jeffrey J. , Helvey J. David
Published: November 2004

Effects of wildfire on water quantity and quality are issues of major concern. Much has been learned from previous research, although site‐specific data from both before and after wildfire are rare. The Entiat Experimental Forest (EEF) in central Washington State provides such a hydrologic record. In August 1970 a severe wildfire occurred following 10 years of stream gauging as part of a controlled land use experiment. A modified data collection program continued through 1977. Existing data from the EEF are available on the internet. Data housed at the site include downloadable daily discharge, air temperature, humidity, precipitation, water temperature, 10‐m DEMs, watershed boundaries, and gauge locations. These data are an archive for assessment of hydrologic response and model formulation, calibration, and testing. The EEF is being reinstrumented to investigate recovery from effects of the 1970 fire on water quantity, quality, and flow regime.
Transport coefficients of the Lennard-Jones model fluid. II Self-diffusion
Authors: Meier Karsten , Laesecke Arno , Kabelac Stephan
Published: November 2004

In an extensive computer simulation study, the transport coefficients of the Lennard-Jones model fluid were determined with high accuracy from equilibrium molecular-dynamics simulations. In the frame of time-correlation function theory, the generalized Einstein relations were employed to evaluate the transport coefficients. This second of a series of four papers presents the results for the self-diffusion coefficient, and discusses and interprets the behavior of this transport coefficient in the fluid region of the phase diagram. The uncertainty of the self-diffusion data is estimated to be 1% in the gas region and 0.5% at high-density liquid states. With the very accurate data, even fine details in the shape of the self-diffusion isotherms are resolved, and the previously little-investigated behavior of the self-diffusion coefficient at low-density gaseous states is analyzed in detail. Finally, aspects of the mass transport mechanisms on the molecular scale are explored by an analysis of the velocity autocorrelation functions.
The ability of silylenes to bind excess electrons: Electron affinities of SiX2, and SiXY species (X,Y=H,CH3,SiH3,F,Cl,Br)
Authors: Larkin Joseph D. , Schaefer Henry F.
Published: November 2004

Recently, Ishida and co-workers [J. Am. Chem. Soc. 125, 3212 (2003)] have isolated silylene radical anions via the one-electron reduction of isolable cyclic dialkylsilylenes, discovering these corresponding radical anions to be relatively stable at low temperatures. Herein we report theoretical predictions of the adiabatic electron affinities (AEA), vertical electron affinities, and vertical detachment energies of a series of methyl, silyl, and halosubstituted silylene compounds. This research utilizes the carefully calibrated [J. C. Rienstra-Kiracofe, G. S. Tschumper, H. F. Schaefer, S. Nandi, and G. B. Ellison, Chem. Rev. (Washington, DC) 102, 231 (2002)] DZP++ basis with the combination of the popular nonhybrid and hybrid DFT functionals, BLYP, B3LYP, and BHHLYP. The level of theory employed and the ensemble of species under study confirm the ability of silylenes to bind excess electrons with Si(SiH3)2 being the most effective, having a predicted AEA of 1.95 eV. While it is known that methyl substituents have a diminishing effect on the computed electron affinities (EAs), it is shown that fluorine shows an analogous negative effect. Similarly, previous suggestions that Si(CH3)2 will not bind an electron appear incorrect, with EA[Si(CH3)2] predicted here to be 0.46 eV.
Dynamics of (H−,H2) collisions: A time-dependent quantum mechanical investigation on a new ab initio potential energy surface
Authors: Panda Aditya Narayan , Sathyamurthy N.
Published: November 2004

A global analytical potential energy surface for the ground state of H3− has been constructed by fitting an analytic function to the ab initio potential energy values computed using coupled cluster singles and doubles with perturbative triples [CCSD(T)] method and Dunning’s augmented correlation consistent polarized valence triple zeta basis set. Using this potential energy surface, time-dependent quantum mechanical wave packet calculations were carried out to calculate the reaction probabilities (PR) for the exchange reaction H−+H2(v,j)→H2+H−, for different initial vibrational (v) and rotational (j) states of H2, for total angular momentum equal to zero. With increase in v, the number of oscillations in the PR(E) plot increases and the oscillations become more pronounced. While PR increases with increase in rotational excitation from j=0 to 1, it decreases with further increase in j to 2 over a wide range of energies. In addition, rotational excitation quenches the oscillations in PR(E) plots.
Separation of metal ions in nitrate solution by ultrasonic atomization
Authors: Sato Masanori , Ikeno Masayuki , Fujii Toshitaka
Published: November 2004

In the ultrasonic atomization of metal nitrate solutions, the molar ratio of metal ions is changed between solution and mist. Small molar metal ions tend to be transferred to mist by ultrasonic wave acceleration, while large molar ions tend to remain in solution. As a result, metal ions can be separated by ultrasonic atomization. We show experimental data and propose a conceptual mechanism for the ultrasonic separation of metal ions.
Moduli of quantum Riemannian geometries on ⩽4 points
Authors: Majid S. , Raineri E.
Published: November 2004

We classify parallelizable noncommutative manifold structures on finite sets of small size in the general formalism of framed quantum manifolds and vielbeins introduced previously [S. Majid, Commun. Math. Phys. 225, 131 (2002)]. The full moduli space is found for ⩽3 points, and a restricted moduli space for 4 points. Generalized Levi–Cività connections and their curvatures are found for a variety of models including models of a discrete torus. The topological part of the moduli space is found for ⩽9 points based on the known atlas of regular graphs. We also remark on aspects of quantum gravity in this approach.
Vibrational relaxation of oxygen in an argon cage
Authors: Shin H. K.
Published: November 2004

The vibrational relaxation of oxygen embedded in an argon cage through vibrational to local translation, rotation, and argon phonon modes has been studied using semiclassical procedures. The collision model is based on the trapped molecule undergoing the restricted motions (local translation and hindered rotation) in a cage formed by its twelve nearest argon neighbors in a face-centered-cubic structure. At 85 K in the liquid argon temperature range, the deexcitation probability of O2(v=1) is 5.8×10−12 and the relaxation rate constant with the collision frequency from local translation is 23 s−1. The rate constant decreases to 5.1 s−1 at 50 K and to 0.016 s−1 at 10 K in the solid argon temperature range. Transfer of the vibrational energy to local translation, rotation (both hindered and free), and argon phonon modes is the relaxation pathway for the trapped oxygen molecule.
Interaction of NaCl with solid water
Authors: Borodin A. , Höfft O. , Kahnert U. , Kempter V. , Poddey A. , Blöchl P. E.
Published: November 2004

The interaction of NaCl with solid water, deposited on tungsten at 80 K, was investigated with metastable impact electron spectroscopy (MIES) and ultraviolet photoelectron spectroscopy (UPS) (He I). We have studied the ionization of Cl(3p) and the 1b1, 3a1, and 1b2 bands of molecular water. The results are supplemented by first-principles density functional theory (DFT) calculations of the electronic structure of solvated Cl− ions. We have prepared NaCl/water interfaces at 80 K, NaCl layers on thin films of solid water, and H2O ad-layers on thin NaCl films; they were annealed between 80 and 300 K. At 80 K, closed layers of NaCl on H2O, and vice versa, are obtained; no interpenetration of the two components H2O and NaCl was observed. However, ionic dissociation of NaCl takes place when H2O and NaCl are in direct contact. Above 115 K solvation of the ionic species Cl− becomes significant. Our results are compatible with a transition of Cl− species from an interface site (Cl in direct contact with the NaCl lattice) to an energetically favored configuration, where Cl species are solvated. The DFT calculations show that Cl− species, surrounded by their solvation shell, are nevertheless by some extent accessed by MIES because the Cl(3p)-charge cloud extends through the solvation shell. Water desorption is noticeable around 145 K, but is not complete before 170 K, about 15 K higher than for pure solid water. Above 150 K the NaCl-induced modification of the water network gives rise to gas phase like structures in the water spectra. In particular, the 3a1 emission turns into a well-defined peak. This suggests that under these conditions water molecules interact mainly with Cl− rather than among themselves. Above 170 K only Cl is detected on the surface and desorbs around 450 K.
Nonadiabatic energy transfer studies of O(1D)+N2(X 1Σg+)→O(3P)+N2(X 1Σg+) by time-dependent wave packet
Authors: Chu Tian-Shu , Xie Ting-Xian , Han Ke-Li
Published: November 2004

Three-dimensional time-dependent quantum calculations have been performed on two/three coupled potential surfaces, including the singlet surface 1 1A′ and two triplet surfaces 1 3A′ and 1 3A″, for the electronic quenching process of O(1D)+N2(X 1Σg+)→O(3P)+N2(X 1Σg+). An extended split-operator scheme was employed to study this nonadiabatic process. Two types of singlet surface 1 1A′, namely, double many body expansion (DMBE2) [Nakamura and Kato, J. Chem. Phys. 110, 9937 (1999)] and ZPM2 [Zahr, Preston, and Miller, J. Chem. Phys. 62, 1127 (1975)] were used in the calculations, along with spin–orbit couplings of Nakamura–Kato and with a constant value of 80 cm−1. All the calculated probabilities are resonance dominated, with a general decreasing trend within the investigated collision energy range. The probability involving three potential energy surfaces is approximately two times as high as that on two potential energy surfaces. At low collision energies, the calculations on the ZPM2 surface produced much larger probability than that on the DMBE2 surface, but the difference was diminishing as the collision energy became high. The behavior of the probability on DMBE2/ZPM2 surfaces at low energies indicates that the ZPM2 surface dominates over the DMBE2 surface in the description of the process. However, the DMBE2 surface has been modified by removing the unreasonable barrier. The estimated quenching cross sections both on the ZPM2 surface and on the modified DMBE2 surface in the three-coupled-surface calculations agree with the experimental measurement. Also, a rather insensitive characteristic of the probability relative to the analytical function form of spin–orbit coupling is revealed.
Microrheology of entangled polymer solutions
Authors: Furukawa Akira
Published: November 2004

Microrheology of semidilute polymer solutions is investigated. In this paper we calculate a response function of a probe particle embedded in a semidilute polymer solution by analyzing the two-fluid model. We find that when the size of the probe particle is comparable to the viscoelastic length, the response from the longitudinal compression modes becomes more important than that of the transverse shear modes. As a result, depending on the circumstances, the obtained complex shear modulus cannot be well approximated by that measured in macroscopic rheology experiments. The present results are due to the dynamical asymmetry coupling and the existence of the cooperative dynamics, which are intrinsic to entangled polymer solutions.
Pendular-state spectroscopy of the S1–S electronic transition of 9-cyanoanthracene
Authors: Kanya Reika , Ohshima Yasuhiro
Published: November 2004

Fluorescence excitation spectra of the S1–S0 origin band of 9-cyanoanthracene have been observed under a uniform electric field up to 200 kV/cm to explore pendular-state spectrum of an asymmetric-top molecule close to the strong field limit. The observed spectra exhibit distinct evolution of the band contour as a function of the applied electric field, which are much different from each other for different excitation configurations. An approximate method suitable for spectrum simulations of large asymmetric-top molecules in a pendular condition is developed for the analysis of the experimental results. The comparison of the observed and simulated spectra shows that the spectra are well ascribed in terms of the pendular-state selection rules, which have recently been derived from theoretical consideration of the pendular-limit representation of energy levels and spectra [R. Kanya and Y. Ohshima, Phys. Rev. A 70, 013403 (2004)].
Neoclassical dissipation and resistive wall modes in tokamaks
Authors: Shaing K. C.
Published: November 2004

It is shown that the critical toroidal plasma flow speed that is required to stabilize the resistive wall mode in tokamaks is reduced by a factor of the order of B/Bθ or of 1.265ε3/4B/Bθ depending on the plasma parameters when the perturbed neoclassical viscosity driven current is taken into account. Here, B is the magnetic field strength, Bθ is the poloidal magnetic field strength, and ε is the inverse aspect ratio. This effect is illustrated using an existing model for the resistive wall modes by including the neoclassical dissipation in the derivation of the dispersion relation. The derivation is based on fluid equations with the plasma viscosity, calculated using kinetic equation, as the closure. The reduction of the critical toroidal speed is a consequence of the parallel (to the magnetic field B) momentum equation when neoclassical viscosity becomes important. The results are compared with experimental observations in tokamaks.
Network structures of polyhedral oligomeric silsesquioxane based nanocomposites: A Monte Carlo study
Authors: Sheng Yu-Jane , Lin Wei-Jung , Chen Wen-Chang
Published: November 2004

The network structures of polyhedral oligomeric silsesquioxane based nanocomposites are studied by continuous-space Monte Carlo simulations. The nanoporous network contains intercubic pores and mesopores which can be clearly identified in this work. In terms of degree of cross linking and pore size distribution (PSD), effects of linker length, tether rigidity, and number of reactive tethers are examined. It is found that the extent of cross linking as well as the intercubic pore size of the network increases as linker length increases which are consistent with experimental findings. However, the mesopores appear to shift to a smaller radii regime for networks with longer linkers. Networks with rigid tethers contain lots of free linkers, thus, low cross linking density and narrow PSD are observed. On the other hand, reduction of the reactive tethers shows an insignificant effect on the degree of cross linking of the system. The fact that the intercubic pore size increases as the number of reactive tethers decreases causes the nanobuilding blocks to possess larger free volumes and distribute themselves more evenly throughout the system. As a result, it reduces the possibility of forming large mesopores.
Transport of bubbles in square microchannels
Authors: Cubaud Thomas , Ho Chih-Ming
Published: November 2004

Liquid/gas flows are experimentally investigated in 200 and 525 μm square microchannels made of glass and silicon. Liquid and gas are mixed in a cross-shaped section in a way to produce steady and homogeneous flows of monodisperse bubbles. Two-phase flow map and transition lines between flow regimes are examined. Bubble velocity and slip ratio between liquid and gas are measured. Flow patterns and their characteristics are discussed. Local and global dry out of the channel walls by moving bubbles in square capillaries are investigated as a function of the flow characteristics for partially wetting channels. Two-phase flow pressure drop is measured and compared to single liquid flow pressure drop. Taking into account the homogeneous liquid fraction along the channel, an expression for the two-phase hydraulic resistance is experimentally developed over the range of liquid and gas flow rates investigated.
The ground state tunneling splitting of malonaldehyde: Accurate full dimensional quantum dynamics calculations
Authors: Coutinho-Neto Maurı́cio D. , Viel Alexandra , Manthe Uwe
Published: November 2004

Benchmark calculations of the tunneling splitting in malonaldehyde using the full dimensional potential proposed by Yagi et al. [J. Chem. Phys. 115, 10647 (2001)] are reported. Two exact quantum dynamics methods are used: the multiconfigurational time-dependent Hartree (MCTDH) approach and the diffusion Monte Carlo based projection operator imaginary time spectral evolution (POITSE) method. A ground state tunneling splitting of 25.7±0.3 cm−1 is calculated using POITSE. The MCTDH computation yields 25 cm−1 converged to about 10% accuracy. These rigorous results are used to evaluate the accuracy of approximate dynamical approaches, e.g., the instanton theory.
Theory for the breathing mode of a complex plasma disk
Authors: Sheridan T. E.
Published: November 2004

A nonlinear equation of motion for the breathing-mode oscillation of a complex plasma disk is derived. Particles interact via a shielded Coulomb force with a Debye length λ and are confined in a parabolic potential well. Damping is due to the Epstein drag force. This system is modeled as a circular disk having uniform charge and mass densities. The equilibrium radius R0 and breathing frequency ωbr are calculated as a function of λ and d, the effective nearest-neighbor separation. For the unshielded Coulomb force (λ→∞), ωbr2=3. When R0/λ≪1, ωbr2−3 varies as (R0/λ)2. When R0/λ≫1, the value of ωbr depends on d. In the plasma regime d≪λ, ωbr2∼4, while in the nearest-neighbor regime d>λ, ωbr2 increases linearly with R0/λ with a slope proportional to d.
Response of ApoA-IV in pigs to long-term increased dietary oil intake and to the degree of unsaturation of the fatty acids
Authors: Navarro María A. , Acín Sergio , Carnicer Ricardo , Guzmán-García Mario A. , Arbonés-Mainar José M. , Surra Joaquín C. , Cebrián José A. , Arnal Carmen , Isabel Beatriz , López-Bote Clemente J. , Osada Jesús
Published: November 2004

ApoA-IV is a protein constituent of HDL particles; the gene coding for it is a member of the ApoA-I–ApoC-III–ApoA-IV cluster. To investigate the effects of the quantity and the degree of saturation of dietary lipid on the long-term response of this Apo, and on the hypothetical coordinated regulation of the clusterin vivo, pigs were fed isoenergetic, cholesterol-free, low-lipid or lipid-enriched diets (containing either extra olive oil (rich in MUFA) or sunflower oil (rich inn−6 PUFA)) for 42 d. In animals fed on the control diet, ApoA-IV was mainly associated with plasma lipoproteins. An increase in plasma ApoA-IV concentration, mainly in the lipoprotein-free fraction, was induced by the lipid-enriched diets, independent of the degree of saturation of the fatty acids involved. The latter diets also led to increases in hepatic ApoA-I, ApoA-IV and ApoC-III mRNA levels, more so with the sunflower oil-rich diet. The present results show that porcine plasma ApoA-IV levels and their association with lipoproteins are very sensitive to increases in dietary lipids, independent of the degree of fatty acid saturation. Furthermore, hepatic expression of RNA appears to be coordinated along with that of the other members of the gene cluster.
Lactobacillus gasseri: effects on mouse intestinal flora enzyme activity and isoflavonoids in the caecum and plasma
Authors: Tamura Motoi , Ohnishi-Kameyama Mayumi , Shinohara Kazuki
Published: November 2004

The effects of Lactobacillus gasseri JCM 1131T on isoflavonoid levels within the caecum and plasma were assessed in adult mice. Male 5-week-old mice were fed an AIN 93M diet for 30 d. Two groups of mice were administered either L. gasseri JCM 1131T (the LGI group) or physiological saline solution (the control (CI) group) daily for 5 d before dissection. The plasma daidzein concentration was significantly higher in the LGI group, however, their plasma equol concentration was significantly less than in the CI group. The total amount of equol present as aglycone in the caecum was significantly greater in the CI group, but there was no significant difference in the total daidzein present as caecal aglycone. In an in vitro incubation of daidzin with the faecal flora of mice, the equol concentration was significantly higher in the CI group. The numbers of lactobacilli present were significantly higher in the LGI group. The present data suggest that the administration of L. gasseri is likely to influence the effect of isoflavonoids on the host via changes in the gastrointestinal environment.
Energy restriction initiated at different gestational ages has varying effects on maternal weight gain and pregnancy outcome in common marmoset monkeys (Callithrix jacchus)
Authors: Tardif Suzette , Power Michael , Layne Donna , Smucny Darlene , Ziegler Toni
Published: November 2004

With relatively high fertility and short lifespan, marmoset monkeys (Callithrix jacchus) may become useful primate models of prenatal nutritional effects on birth condition and adult disease risk. The present study determined the effects of energy restriction to 75% of expected ad libitum consumption during mid- (day 66) or late (day 99) gestation on maternal weight, fetal growth and pregnancy outcomes in this species. Mid-restriction reliably induced the loss of pregnancy before term, at 92 d, on average. Of the late-restricted pregnancies, four of seven were normal term length while three were preterm deliveries, at 101, 117 and 132 d. Control females had a mean mid-pregnancy weight gain of 0·67 g/d while mid-restricted females lost −0·65 g/d, on average. Control pregnancies averaged a 1·06 g/d gain during late pregnancy, while energy-restricted females lost −0·67 g/d, on average. Restriction-related weight change was highly variable, ranging from +0·55 to −2·56 g/d for mid-restriction pregnancies and from +0·79 to −3·91 g/d for late-restriction pregnancies. For mid-restriction pregnancies, the number of restriction days was best explained by linear weight change and total weight loss while the number of restriction days in late pregnancy was best explained by linear weight change alone. In late-restriction pregnancies, smaller females had higher daily weight losses. Restrictions did not induce litter-size reduction or growth restriction in those infants that were delivered at term but the size of aborted fetuses suggested that at least some pregnancies lost preterm may have involved impaired intra-uterine growth.
Insulin Inhibits Platelet-derived Growth Factor-induced Cell Proliferation
Authors: Cirri P. , Taddei M. L. , Chiarugi P. , Buricchi F. , Caselli A. , Paoli P. , Giannoni E. , Camici G. , Manao G. , Raugei G. , Ramponi G.
Published: November 2004

Cellular behavior can be considered to be the result of a very complex spatial and temporal integration of intracellular and extracellular signals. These signals arise from serum-soluble factors as well as from cell–substrate or cell–cell interactions. The current approach in mitogenesis studies is generally to analyze the effect of a single growth factor on serum-starved cells. In this context, a metabolic hormone such as insulin is found to be a mitogenic agent in many cellular types. In the present study, we have considered the effect of insulin stimulation in platelet-derived growth factor (PDGF)-activated NIH-3T3 and C2C12 cells. Our results show that insulin is able to inhibit strongly both NIH-3T3 and C2C12 cell growth induced by PDGF, one of the most powerful mitotic agents for these cell types. This inhibitory effect of insulin is due primarily to a premature down-regulation of the PDGF receptor. Thus, when NIH-3T3 or C2C12 cells are stimulated with both PDGF and insulin, we observe a decrease in PDGF receptor phosphorylation with respect to cells treated with PDGF alone. In particular, we find that costimulation with insulin leads to a reduced production of H2O2with respect to cell stimulation with PDGF alone. The relative low concentration of H2O2in PDGF/insulin-costimulated cell leads to a limited down-regulation of protein tyrosine phosphatases, and, consequently, to a reduced PDGF receptor phosphorylation efficiency. The latter is very likely to be responsible for the insulin-dependent inhibition of PDGF-receptor mitogenic signaling.
Mycobacterium tuberculosisFunctional Network Analysis by Global Subcellular Protein Profiling
Authors: Mawuenyega Kwasi G. , Forst Christian V. , Dobos Karen M. , Belisle John T. , Chen Jin , Bradbury E. Morton , Bradbury Andrew R.M. , Chen Xian
Published: November 2004

Trends in increased tuberculosis infection and a fatality rate of ∼23% have necessitated the search for alternative biomarkers using newly developed postgenomic approaches. Here we provide a systematic analysis of Mycobacterium tuberculosis (Mtb) by directly profiling its gene products. This analysis combines high-throughput proteomics and computational approaches to elucidate the globally expressed complements of the three subcellular compartments (the cell wall, membrane, and cytosol) of Mtb. We report the identifications of 1044 proteins and their corresponding localizations in these compartments. Genome-based computational and metabolic pathways analyses were performed and integrated with proteomics data to reconstruct response networks. From the reconstructed response networks for fatty acid degradation and lipid biosynthesis pathways in Mtb, we identified proteins whose involvements in these pathways were not previously suspected. Furthermore, the subcellular localizations of these expressed proteins provide interesting insights into the compartmentalization of these pathways, which appear to traverse from cell wall to cytoplasm. Results of this large-scale subcellular proteome profile of Mtb have confirmed and validated the computational network hypothesis that functionally related proteins work together in larger organizational structures.
Gap Junctions Regulate Extracellular Signal-regulated Kinase Signaling to Affect Gene Transcription
Authors: Stains Joseph P. , Civitelli Roberto
Published: November 2004

Osteoblasts are highly coupled by gap junctions formed by connexin43. Overexpression of connexin45 in osteoblasts results in decreased chemical and electrical coupling and reduces gene transcription from connexin response elements (CxREs) in the osteocalcin and collagen Iα1 promoters. Here, we demonstrate that transcription from the gap junction-dependent osteocalcin CxRE is regulated by extracellular signal-regulated protein kinase (ERK) and phosphatidylinositol 3-kinase (PI3K) cascades. Overexpression of a constitutively active mitogen-activated protein kinase kinase (MEK), Raf, or Ras can increase transcription more than twofold of the CxRE, whereas inhibition of MEK or PI3K can decrease transcription threefold from the osteocalcin CxRE. Importantly, disruption of gap junctional communication by overexpression of connexin45 or treatment with pharmacological inhibitors of gap junctions results in reduced Raf, ERK, and Akt activation. The consequence of attenuated gap junction-dependent signal cascade activation is a decrease in Sp1 phosphorylation by ERK, resulting in decreased Sp1 recruitment to the CxRE and inhibited gene transcription. These data establish that ERK/PI3K signaling is required for the optimal elaboration of transcription from the osteocalcin CxRE, and that disruption of gap junctional communication attenuates the ability of cells to respond to an extracellular cue, presumably by limiting the propagation of second messengers among adjacent cells by connexin43-gap junctions.
Coupling of Posterior Cytoskeletal Morphogenesis to the G1/S Transition in theTrypanosoma bruceiCell Cycle
Authors: Tu Xiaoming , Wang Ching C.
Published: November 2004

The expression levels of four Cdc2-related kinases (CRK1, 2, 4, and 6) in the procyclic form of Trypanosoma brucei were knocked down in pairs using the RNA interference (RNAi) technique. A double knockdown of CRK1 and CRK2 resulted in arrested cell growth in the G1 phase accompanied by an apparent cessation of nuclear DNA synthesis. The arrested cells became elongated at the posterior end like the G1-phase cells generated by knockdown of CycE1/CYC2 in a previous study. However, ∼5% of the G1 cells in the current study also possessed multiply branched posterior ends, which have not previously been observed in T. brucei. DAPI and immunofluorescence staining showed a single nucleus, kinetoplast, basal body, and flagellum in the anterior portion of each G1 cell. The split and grossly extended posterior ends were heavily stained with antibodies to tyrosinated α-tubulin, suggesting an accumulation of newly synthesized microtubules. A significant population of anucleate cells (zoids), apparently derived from kinetoplast-dictated cytokinesis and cell division of the G1 cells, also had extended and branched posterior ends filled with newly synthesized microtubules. This continued posterior extension of microtubules in the G1 cells and zoids suggests that CRK1 and CRK2 exert a coordinated control on G1/S passage and the limited growth of the microtubule corset toward the posterior end. This connection may provide a new insight into the mechanism of morphological maintenance of an ancient protist during its cell cycle progression.
ERdj3, a Stress-inducible Endoplasmic Reticulum DnaJ Homologue, Serves as a CoFactor for BiP's Interactions with Unfolded Substrates
Authors: Shen Ying , Hendershot Linda M.
Published: November 2004

We recently identified ERdj3 as a component of unassembled immunoglobulin (Ig) heavy chain:BiP complexes. ERdj3 also associates with a number of other protein substrates, including unfolded light chains, a nonsecreted Ig light chain mutant, and the VSV-G ts045 mutant at the nonpermissive temperature. We produced an ERdj3 mutant that was unable to stimulate BiP's ATPase activity in vitro or to bind BiP in vivo. This mutant retained the ability to interact with unfolded protein substrates, suggesting that ERdj3 binds directly to proteins instead of via interactions with BiP. BiP remained bound to unfolded light chains longer than ERdj3, which interacted with unfolded light chains initially, but quickly disassociated before protein folding was completed. This suggests that ERdj3 may bind first to substrates and serve to inhibit protein aggregation until BiP joins the complex, whereas BiP remains bound until folding is complete. Moreover, our findings support a model where interactions with BiP help trigger the release of ERdj3 from the substrate:BiP complex.
Staufen Recruitment into Stress Granules Does Not Affect Early mRNA Transport in Oligodendrocytes
Authors: Thomas María G. , Tosar Leandro J. Martinez , Loschi Mariela , Pasquini Juana M. , Correale Jorge , Kindler Stefan , Boccaccio Graciela L.
Published: November 2004

Staufen is a conserved double-stranded RNA-binding protein required for mRNA localization in Drosophila oocytes and embryos. The mammalian homologues Staufen 1 and Staufen 2 have been implicated in dendritic RNA targeting in neurons. Here we show that in rodent oligodendrocytes, these two proteins are present in two independent sets of RNA granules located at the distal myelinating processes. A third kind of RNA granules lacks Staufen and contains major myelin mRNAs. Myelin Staufen granules associate with microfilaments and microtubules, and their subcellular distribution is affected by polysome-disrupting drugs. Under oxidative stress, both Staufen 1 and Staufen 2 are recruited into stress granules (SGs), which are stress-induced organelles containing transiently silenced messengers. Staufen SGs contain the poly(A)-binding protein (PABP), the RNA-binding proteins HuR and TIAR, and small but not large ribosomal subunits. Staufen recruitment into perinuclear SGs is paralleled by a similar change in the overall localization of polyadenylated RNA. Under the same conditions, the distribution of recently transcribed and exported mRNAs is not affected. Our results indicate that Staufen 1 and Staufen 2 are novel and ubiquitous SG components and suggest that Staufen RNPs are involved in repositioning of most polysomal mRNAs, but not of recently synthesized transcripts, during the stress response.
Actin and Septin Ultrastructures at the Budding Yeast Cell Cortex
Authors: Rodal Avital A. , Kozubowski Lukasz , Goode Bruce L. , Drubin David G. , Hartwig John H.
Published: November 2004

Budding yeast has been a powerful model organism for studies of the roles of actin in endocytosis and septins in cell division and in signaling. However, the depth of mechanistic understanding that can be obtained from such studies has been severely hindered by a lack of ultrastructural information about how actin and septins are organized at the cell cortex. To address this problem, we developed rapid-freeze and deep-etch techniques to image the yeast cell cortex in spheroplasted cells at high resolution. The cortical actin cytoskeleton assembles into conical or mound-like structures composed of short, cross-linked filaments. The Arp2/3 complex localizes near the apex of these structures, suggesting that actin patch assembly may be initiated from the apex. Mutants in cortical actin patch components with defined defects in endocytosis disrupted different stages of cortical actin patch assembly. Based on these results, we propose a model for actin function during endocytosis. In addition to actin structures, we found that septin-containing filaments assemble into two kinds of higher order structures at the cell cortex: rings and ordered gauzes. These images provide the first high-resolution views of septin organization in cells.
Compulsory Corsican language classes in school as a method for reversing the language shift to French?
Authors: Blackwood Robert J.
Published: November 2004

After 200 years of gallicisation, the French island of Corsica is experiencing for the first time institutional support for the Corsican language. In 1999, measures were introduced to make the teaching of Corsican compulsory for all students of secondary‐school age, starting with the cohort of that academic year. Mandatory Corsican language classes have long been an aim of language activists on the island, but it is important to measure the public reaction to these measures, certainly in order to evaluate the chances of reviving the Corsican language in the shadow of a powerful, dominant H language, French.
Review article: impact of night‐time reflux on lifestyle − unrecognized issues in reflux disease
Authors: Shaker R. , Brunton S. , Elfant A. , Golopol L. , Ruoff G. , Stanghellini V.
Published: November 2004

Gastro‐oesophageal reflux disease (GERD), manifesting with symptoms including heartburn and regurgitation, affects people during both daytime and nocturnal hours. Night‐time GERD has been reported to have a greater impact on a patient's life than daytime GERD due to prolonged oesophageal acid exposure time per reflux episode. To further understand this issue, it is important to implement quality of life (QOL) measures. QOL studies are becoming increasingly important to physicians in making clinical decisions, and generic and disease‐specific health‐related QOL (HRQL) tools have been developed to measure a wide variety of topics. There are currently no universally accepted guidelines on how to best measure HRQL in GERD patients. It is important to note that these surveys may not yield accurate results because many GERD sufferers may feel that their symptoms are not serious enough to seek treatment. Some surveys include the GERD‐HRQL assessment, the Short Form Health Survey (SF‐36), and the Gallup survey. When compared with daytime GERD patients, night‐time GERD patients may suffer from sleep deprivation, which in turn leads to physical and emotional problems and a poor overall QOL. Studies indicate that the prevalence and impact of night‐time heartburn have been underestimated and that adequate treatment of symptoms is often not achieved. In addition, GERD greatly affects work productivity and leads to a significant economic burden on society. Although limited studies are available on the impact of pharmacological treatment on GERD QOL, recent findings indicate that proton pump inhibitors are more effective than H2‐receptor antagonists for the improvement of overall QOL.