bluuebunny/crossref_metadata_2025 huggingface dataset:
Attitudes and knowledge about osteoporosis risk prevention: a survey of New Zealand women
Authors: von Hurst Pamela R , Wham Carol A
Published: February 2007

Objectives

The purpose of this study was to investigate the knowledge and health beliefs regarding osteoporosis risk factors of New Zealand women aged 20–49 years.

Design

A descriptive, web-based survey.

Subjects

An opportunistic sample of 622 women aged between 20 and 49 years living in Auckland, New Zealand was recruited by email.

Results

There was a moderate level of knowledge about osteoporosis risk factors among the women surveyed, with a mean total score for all subjects of 16.4 (standard deviation (SD) 4.0) out of a possible 26 correct responses. Mean scores for osteoporosis knowledge were statistically different by age group, with women aged 40–49 years scoring higher than those aged 30–39 years and 20–29 years (17.3 (SD 4.0), 16.4 (SD 4.1) and 15.8 (SD 3.9), respectively, P < 0.001). Overall, about a third of the women perceived that they were likely to develop osteoporosis and 22% believed the disease to be potentially crippling. Most women were aware of the benefits of exercise and optimal calcium nutrition in preventing osteoporosis. Few women perceived barriers to exercise participation and eating calcium-rich foods. Older women (40–49 years) were more motivated to take care of their health than younger women (P < 0.001). A large percentage of subjects (77%) thought that calcium-rich foods contained too much cholesterol.

Conclusions

Despite reporting higher than average educational attainment and health consciousness, these women demonstrated average levels of knowledge about osteoporosis risk factors. They had low feelings of susceptibility towards development of osteoporosis, but most considered it to be a serious disease.
Plasma micronutrients are associated with dietary intake and environmental tobacco smoke exposure in a paediatric population
Authors: Brady Heather , Lamb Molly M , Sokol Ronald J , Ross Colleen A , Seifert Jennifer A , Rewers Marian J , Norris Jill M
Published: February 2007

Background

While adult populations have been well described in terms of nutritional status, such as the concentration of nutrient biomarkers, little work has been done in healthy paediatric populations.

Objective

The primary objective of this analysis was to explore the determinants of plasma micronutrients in a group of healthy infants and children.

Design

The Diabetes Autoimmunity Study in the Young (DAISY) has enrolled 1433 newborns at increased risk for type 1 diabetes in Denver, Colorado. A representative random sample of 257 children from the DAISY cohort between the ages of 9 months and 8 years with a total of 815 clinic visits over time was used in this analysis. Annual dietary intake was assessed over time with Willett food-frequency questionnaires that were validated in this population. Environmental tobacco smoke (ETS) was assessed using a validated survey. Plasma samples were tested for vitamins, carotenoids and total lipids. Predictors of plasma micronutrients were evaluated using mixed models for longitudinal data, while adjusting for age, human leukocyte antigen genotype, type 1 diabetes family history and other potential confounders and covariates.

Results

Increased micronutrient intake was associated with increased levels of their respective plasma nutrient, with the exception of γ-tocopherol. Independent of dietary intake, levels of α- and β-carotene and β-cryptoxanthin were significantly lower, and γ-tocopherol was significantly higher, in children who were exposed to ETS.

Conclusion

Dietary intake predicts plasma micronutrient levels. Exposure to ETS potentially could have negative health effects in this young population.
Raman spectroscopic study of the photoprotection of extremophilic microbes against ultraviolet radiation
Authors: Edwards H.G.M. , Moeller R. , Jorge Villar S.E. , Horneck G. , Stackebrandt E.
Published: February 2007

Extremophiles use a range of pigments for protection against low-wavelength radiation in exposed terrestrial habitats and photoaccessory materials are synthesized for the effective harnessing of photosynthetically active radiation. Raman spectroscopy has been demonstrated to be a useful probe for information on the survival strategies employed by extremophilic bacteria through the identification of key biomolecular signatures of the suite of protective chemicals synthesized by the organisms in stressed environments. Raman spectroscopic analyses of Bacillus spp. spores, Bacillus atrophaeus (DSM 675: deep red) and Bacillus subtilis (DSM 5611: light grey and DSM 7264: dark grey), Deinococcus radiodurans (pink) and Natronomonas pharaonis (red), of visually different pigmentation showed the presence of different carotenoids and other protectant biomolecules, which assist microorganisms against UVA radiation. The implications for the survival of extremophilic microbes in extraterrestrial habitats and for the detection of the protectant biomolecules by remote, robotic Raman spectroscopic instrumentation in an astrobiological search for life context are discussed.
Generation of fine hydromagmatic ash by growth and disintegration of glassy rinds
Authors: Mastin Larry G.
Published: February 2007

The deposits of mafic hydromagmatic eruptions are more fine grained and variable in vesicularity than dry magmatic deposits. Blocky, equant shapes of many hydromagmatic clasts also contrast with droplet, thread, and bubble wall morphology of dry magmatic fragments. Small (<∼180 μm), blocky hydromagmatic pyroclasts have traditionally been interpreted to result from discrete vapor explosions, although such explosions tend to occur only under certain conditions. This paper considers a process of hydromagmatic ash formation that involves repeated growth and disintegration of glassy rinds on pyroclast surfaces as they deform within turbulent flows. This process, termed “turbulent shedding”, may occur during the expansion phase of vapor explosions or during turbulent but nonexplosive mixing of magma with water, steam, or water sprays. The occurrence of turbulent shedding and the resulting fragment sizes depend on the timescale for rind growth and the timescale between disturbances that remove or disintegrate glassy rinds. Turbulent shedding is directly observable in some small littoral jets at Kilauea. Calculations suggest that, in the presence of liquid water or water sprays, glassy rinds having a thickness of microns to millimeters should form in milliseconds to seconds. This is similar to the timescale between turbulent velocity fluctuations that can shred lava globules and remove such rinds. The fraction of a deposit consisting of fine ash should increase with the duration of this process: Large‐scale Surtseyan jets generate hundreds or thousands of shedding events; bubble bursts or tephra jets at Kilauea's coast may produce only a few.
Data‐driven solar wind model and prediction of type II bursts
Authors: Florens M. S. L. , Cairns Iver H. , Knock S. A. , Robinson P. A.
Published: February 2007

Type II solar radio bursts are produced by shock waves moving through the corona and solar wind. An existing theory predicts Type II dynamic spectra by considering electron acceleration at the shock, growth of Langmuir waves, and their conversion into radiation. Two contributions are presented, both relevant to space weather research and missions like STEREO. First, a more realistic 2‐dimensional model for the solar wind is developed, based on spacecraft data at 1 AU, and illustrated for a specific period. It relates time to longitude and extrapolates to different heliocentric distances using MHD style equations and power‐law temperature models. Second, the type II theory is combined with the data‐driven solar wind model to predict the dynamic spectrum of a specific Type II burst. The results show reasonable semiquantitative agreement with observations. Issues and possible improvements are outlined.
Lightning‐produced NOx in an explicit electrical scheme tested in a Stratosphere‐Troposphere Experiment: Radiation, Aerosols, and Ozone case study
Authors: Barthe Christelle , Pinty Jean‐Pierre , Mari Céline
Published: February 2007

An explicit lightning‐produced nitrogen oxide (LNOx) scheme has been implemented in a 3‐D mesoscale model. The scheme is based on the simulation of the electrical state of the cloud and provides a prediction of the temporal and spatial distribution of the lightning flashes. The frequency and the 3‐D morphology of the lightning flashes are captured realistically so fresh nitrogen oxide molecules can be added along the complex flash path as a function of the pressure, as suggested by results from laboratory experiments. The scheme is tested on the 10 July 1996 Stratosphere‐Troposphere Experiment: Radiation, Aerosols, and Ozone (STERAO) storm. The model reproduces many features of the observed increase of electrical activity and LNOx flux density between the multicell and supercell stages. LNOx dominates the NOx budget in the upper part of the cells with instantaneous peak concentrations exceeding 4 ppbv, as observed. The computed flux of NOx across the anvil shows a mean value of 6 mol m−2 s−1 during the last 90 min of the simulation. This value is remarkably stable and compares favorably with the observations.
Laboratory measurements of the oxidation kinetics of organic aerosol mixtures using a relative rate constants approach
Authors: Huff Hartz Kara E. , Weitkamp Emily A. , Sage Amy M. , Donahue Neil M. , Robinson Allen L.
Published: February 2007

Organic aerosols in the atmosphere are exposed to oxidants, but the oxidation kinetics are largely unknown. We investigate the decay of organic species in laboratory‐generated organic aerosols exposed to atmospherically relevant ozone concentrations in a smog chamber. The experiments were conducted using five different organic aerosols, varying in complexity from three to twelve components. These mixtures include alkenoic acids, alkanoic acids, alkanedioic acids, n‐alkanes, and sterols and are designed to simulate meat cooking emissions. A relative rate constants approach was used to compare reaction rates of individual organic species and to compare the reaction rates of the aerosol species to gas phase tracers. Significant decay was observed for all species (except for the n‐alkanes) in at least one of the experimental systems. By relating the decomposition of condensed phase alkenoic acids to gas phase alkenes, we show that the reaction rate constants of oleic acid and palmitoleic acid evolve as the aerosol is processed, decreasing by a factor of ∼10 over the course of a 4‐hour experiment. The decay rate constants of cholesterol, oleic acid, and palmitic acid all depend strongly on aerosol composition, with more than an order of magnitude change in the effective rate constants depending on mixture composition. Effects of aerosol composition are likely to be even more significant in atmospheric aerosol, where particle compositions are highly variable. The data presented here indicate these mixture effects are complicated, making it difficult to extrapolate from simple laboratory systems to atmospherically relevant conditions.
Biological Generics: A Business Case
Authors: Sensabaugh Suzanne M.
Published: February 2007

Biological generics are protein products comparable in quality, safety, and efficacy to the brand product and marketed after exclusivity has expired. In the US, sales of biologics are expected to exceed US$60bn by 2010 while in the EU the market size for ‘biosimilars’ is estimated to be US$16–20bn per year by 2010–2011. Biological drugs for which the patent period has expired or is soon to expire include insulin, human growth hormone, interferons, erythropoetin, growth factors, monoclonal antibodies, and blood factors. Not all biological products are currently candidates for various technical and scientific reasons; however, most are. The economics of biological generics will be different than chemical generics. While savings equivalent to a chemical generic may not be realised by the end user, savings in terms of absolute dollars will be substantial. In the EU, so far two ‘biosimilars’ have been approved, while in the US the FDA is reviewing and approving Follow-on Protein Products under the FD&C Act, £505(b)(2). As with chemical generics, challenges and opportunities exist. The entry of biological generics will result in rewards for all. As these products range in the complexity of their molecular structure and indications, the mantra of biologics — case-by-case drug development — will need to be followed.
Influence of impurities and structural properties on the device stability of pentacene thin film transistors
Authors: Knipp D. , Benor A. , Wagner V. , Muck T.
Published: February 2007

The influence of environmental conditions on the electronic transport and the device stability of polycrystalline pentacene transistors were investigated. Electrical in situ and ex situ measurements of pentacene thin film transistors were carried out to study the influence of dry oxygen and moisture on the device operation. The staggered thin film transistors were fabricated by organic molecular beam deposition on thermal oxide dielectrics. Exposing the pentacene films to oxygen leads to the creation of acceptorlike states in the band gap. The acceptorlike states cause a shift of the onset of the drain current towards positive gate voltages. A simple analytical model will be presented which directly correlates the onset voltage of the transistors with the acceptor concentration in the pentacene film. Exposing the pentacene film to moisture causes a drop of the charge carrier mobility, a reduction of the threshold voltage, and a shift of the onset voltage. Besides the creation of acceptorlike states in the pentacene film the interface between the drain and source electrodes and the pentacene film is affected by moisture. The injection of holes in the highest occupied molecular orbital level of the pentacene film is inhibited, which causes an apparent drop of the charge carrier mobility and a reduction of the threshold voltage.
Numerical study of nanosecond laser interactions with micro-sized single droplets and sprays of xenon
Authors: Auguste T. , de Gaufridy de Dortan F. , Ceccotti T. , Hergott J. F. , Sublemontier O. , Descamps D. , Schmidt M.
Published: February 2007

We present a thorough numerical study on interactions of a nanosecond laser with micro-sized xenon droplets. We developed a code which allows simulation of laser interactions with a single droplet as well as a spray. We give a detailed description of the code, and we present results on the dynamics of a microplasma produced by irradiation of a single xenon droplet with a laser focused at peak vacuum intensity in the 5×1010−5×1012 W∕cm2 range. We find that the heating of the plasma depends dramatically on the laser parameters (duration, pulse shape, and intensity) on one hand, and on the droplet diameter on the other. We also present results obtained with a spray which show that the dynamics of the microplasmas is very sensitive to the position of the droplets in the interaction volume. The predictions of our model agree well with recent experimental observations performed on laser-produced plasma sources for extreme ultraviolet lithography. In particular, the postprocessing of our data with a sophisticated atomic physics code has allowed us to reproduce quite well the spectrum emitted in the extreme ultraviolet range by a xenon plasma generated by laser irradiation of a spray of droplets.
Reactive ion etching of high optical quality GaN∕sapphire photonic crystal slab using CH4–H2 chemistry
Authors: Bouchoule S. , Boubanga-Tombet S. , Le Gratiet L. , Le Vassor d’Yerville M. , Torres J. , Chen Y. , Coquillat D.
Published: February 2007

Reactive ion etching (RIE) using a CH4–H2 plasma is investigated for the fabrication of a GaN one-dimensional (1D) photonic crystal (PhC) slab. The dominant control parameter for the etch rate and the sidewall profile is the dc bias. The influence of operating pressure, CH4∕H2 ratio, and total gas flow rate on the etching characteristics is also presented. An etch rate as high as 85nm∕min and an overcut angle as low as 5° obtained in this work are among the best values reported for conventional RIE technique. The CH4–H2 process is used to etch 1D PhCs with a lattice parameter ranging from 700to350nm and an air filling factor of 0.30 into a 600-nm-thick GaN∕sapphire slab. Sharp peaks corresponding to the resonant modes of the nanopatterned structures are observed in the experimental reflection spectra for all the lattice periods. Furthermore, the good optical quality of the nanostructures is evidenced by a resonantly enhanced second-harmonic generation experiment around 400nm. A second-harmonic generation enhancement factor as high as 105 is obtained, compared with the unpatterned GaN reference slab. These results demonstrate that the CH4–H2 conventional RIE technique is well adapted to the etching of GaN PhC for the fabrication of next generation photonic devices exploiting nonlinear processes.
Ultrafast all-optical polarization switching in Bragg-spaced quantum wells at 80K
Authors: Johnston W. J. , Prineas J. P. , Smirl Arthur L.
Published: February 2007

A polarization switch is demonstrated in Bragg-spaced quantum wells at 80K that exhibits a 0.6THz optical bandwidth with a contrast ratio greater than 30dB, a throughput of ∼4%, a switching fluence of 8μJ∕cm2, and a pulse-width-limited picosecond response time. In this device, switching is achieved by using large spin-dependent nonlinearities induced by a circularly polarized control pulse to alter the polarization state of a linearly polarized signal pulse.
Heterojunction thermophotovoltaic devices with high voltage factor
Authors: Huang Robin K. , Ram Rajeev J. , Manfra Michael J. , Connors Michael K. , Missaggia Leo J. , Turner George W.
Published: February 2007

We have demonstrated a heterojunction thermophotovoltaic device. The 0.54eV band gap device has an open-circuit voltage of 360mV for a short circuit current density of 2.7A∕cm2 at T=25°C, which is higher than the open-circuit voltage realized in any other thermophotovoltaic device previously demonstrated having comparable band gaps.
Phenomenological characterization of photoactive centers in Bi12TiO20 crystals
Authors: Frejlich Jaime , Montenegro Renata , Inocente-Junior Nilson R. , dos Santos Pedro V. , Launay Jean Claude , Longeaud Christophe , Carvalho Jesiel F.
Published: February 2007

We report optical and electrical measurements contributing for a better characterization of the relevant photoactive center levels in undoped photorefractive Bi12TiO20 (BTO) crystals grown in Brazil. Comparative results for Pb-doped BTO and Bi12GaO20 are also reported. A center responsible for photochromism was identified at 0.42–0.44eV, probably below the conduction band (CB). The main electron and hole donor center is detected at 2.2eV from the CB and the equilibrium Fermi level is pinned at this level. Other localized centers were identified at different positions in the band gap and their relation with the behavior of BTO under different wavelengths and operating conditions is discussed with particular attention to holographic recording.
Hydrogen-bond assisted enormous broadening of infrared spectra of phenol-water cationic cluster: An ab initio mixed quantum-classical study
Authors: Yamashita Takefumi , Takatsuka Kazuo
Published: February 2007

The infrared spectrum of phenol-water cationic cluster, [PhOH∙H2O]+, taken by Sawamura et al. [J. Phys. Chem. 100, 8131 (1996)] is puzzling in that the peak due to the stretching mode of the phenolic OH (3657cm−1 for a neutral monomer and 3524cm−1 for PhOH∙H2O) seemingly disappears and instead an extremely broad tail extending down to 2900cm−1 is observed. The present authors theoretically ascribe this anomalous spectrum to an inhomogeneous broadening of the OH stretching peak caused by the hydrogen bond, the strength of which has been greatly enhanced by ionization of the phenyl ring. Indeed they estimate that the peak position is at 2300cm−1 and the spectral width can become as wide as 1000cm−1 at the cluster energy of 32kcal∕mol. This surprisingly wide broadening can be generic in hydrogen-bond systems, which in turn is useful to study the nature of the hydrogen-bond assisted dynamics in various systems such as those in DNA and proteins. To study the present system quantitatively, the authors have developed an ab initio mixed quantum-classical method, in which the nuclear motions on an adiabatic ab initio potential surface are treated such that only the OH stretching motion is described quantum mechanically, while all the other remaining modes are treated classically with on-the-fly scheme. This method includes the implementation of many numerical methodologies, which enables it to deal with a relatively large molecular system. With this theoretical method, the authors analyze the present anomalous broadening in a great detail. In particular, they suggest that one can extract direct information about the hydrogen-bond dynamics with respect to the clear correlation between the vibrational excitation energy of the OH stretching and intermolecular distance by means of a time-resolved infrared spectroscopy: Reflecting the slow and wide-range variation of the intermolecular distance of the relevant hydrogen bond, the time-resolved spectrum is predicted to vary (shift) largely covering the wide range of frequency domain. Thus, it is found that the short-time average along a selected trajectory sensitively reflects the change of the intermolecular distance. The authors also study the effect of internal energy on the hydrogen bonding and the OH spectrum.
Hydrodynamic stability of rockets with headwall injection
Authors: Abu-Irshaid Esam M. , Majdalani Joseph , Casalis Grégoire
Published: February 2007

We investigate the hydrodynamic instability of the full-length, cylindrical models of solid and hybrid rockets with headwall injection. Our baseline is the rotational incompressible flowfield proposed in a recent study (Majdalani and Vyas, “Inviscid models of the classic hybrid rocket,” AIAA Paper 2004-3474). The local nonparallel approach is implemented in which the amplitude functions are assumed to be radially dependent at fixed streamwise locations. The usual singularity along the chamber axis is eliminated using Taylor series expansions. As a result, three compatibility relations are derived and substituted for the local boundary conditions along the axis. These depend on whether the tangential wave number q is 0, 1, or larger. Our rotational model is shown to exhibit a range of instability that broadens with successive increases in headwall injection. The lowest frequency below which the flow remains unconditionally stable is observed at ω=28.5 regardless of the headwall injection rate. As usual, the zeroth order tangential mode is found to be the most amplified. Using a representative headwall injection velocity for hybrid rockets, we identify a range of frequencies along which large excursions in pressure and velocity amplitudes are possible. These surges signal the presence of a resonant-like mechanism that is akin to an acoustic instability response. The most excited frequencies vary between 387 and 415 in the vicinity of the headwall. These frequencies are spatially delayed and lowered to 93.8–163.5 when the headwall injection rate is reduced to the level associated with solid rockets. For the most critical streamwise stations, these resurging wave amplitudes are quantified and shown to exhibit spectra that mimic the waterfall data acquired in acoustic instability tests.
Simplified calculation of nonlocal thermodynamic equilibrium excited state populations contributing to 13.5nm emission in a tin plasma
Authors: White J. , Cummings A. , Dunne P. , Hayden P. , O’Sullivan G.
Published: February 2007

Extreme ultraviolet lithography schemes for the semiconductor industry are currently based on coupling radiation from a plasma source into a 2% bandwidth at 13.5nm (91.8eV). In this paper, we consider the case for a laser-produced plasma (LPP) and address the calculation of ionic level populations in the 4p64dN, 4p64dN−14f1, 4p54dN+1, and 4p64dN−15p1 configurations in a range of tin ions (Sn6+ to Sn13+) producing radiation in this bandwidth. The LPP is modeled using a one-dimensional hydrodynamics code, which uses a hydrogenic, average atom model, where the level populations are treated as l degenerate. Hartree-Fock calculations are used to remove the l degeneracy and an energy functional method to calculate the nl level populations involved in n=4−4 transitions as a function of distance from the target surface and time. Detailed data are presented for the tin ions that contribute to in-band emission.
Support of the logarithmic equilibrium measure on sets of revolution in R3
Authors: Hardin D. P. , Saff E. B. , Stahl H.
Published: February 2007

For sets of revolution B in R3, we investigate the limit distribution of minimum energy point masses on B that interact according to the logarithmic potential log(1∕r), where r is the Euclidean distance between points. We show that such limit distributions are supported only on the “outmost” portion of the surface (e.g., for a torus, only on that portion of the surface with positive curvature). Our analysis proceeds by reducing the problem to the complex plane where a nonsingular potential kernel arises, the level lines of which are ellipses.
Compact electrostatic levitator for diffraction measurements with a two axis diffractometer and a laboratory x-ray source
Authors: Masaki Tadahiko , Ishikawa Takehiko , Paradis Paul-François , Yoda Shinichi , Okada Junpei T. , Watanabe Yasuhiro , Nanao Susumu , Ishikura Akiko , Higuchi Kensuke , Mizuno Akitoshi , Watanabe Masato , Kohara Shinji
Published: February 2007

A compact electrostatic levitator was developed for the structural analysis of high-temperature liquids by x-ray diffraction methods. The size of the levitator was 200mm in diameter and 200mm in height and can be set up on a two axis diffractometer with a laboratory x-ray source, which is very convenient in performing structural measurements of high-temperature liquids. In particular, since the laboratory x-ray source allows a great amount of user time, preliminary or challenging experiments can be performed with trial and error, which prepares and complements synchrotron x-ray experiments. The present small apparatus also provides the advantage of portability and facility of setting. To demonstrate the capability of this electrostatic levitator, the static structure factors of alumina and silicon samples in their liquid phases were successfully measured.
Photoionization in negative streamers: Fast computations and two propagation modes
Authors: Luque Alejandro , Ebert Ute , Montijn Carolynne , Hundsdorfer Willem
Published: February 2007

Streamer discharges play a central role in electric breakdown of matter in pulsed electric fields, both in nature and in technology. Reliable and fast computations of the minimal model for negative streamers in simple gases such as nitrogen have recently been developed. However, photoionization was not included; it is important in air and poses a major numerical challenge. The authors here introduce a fast and reliable method to include photoionization into our numerical scheme with adaptive grids, and they discuss its importance for negative streamers. In particular, they identify different propagation regimes where photoionization does or does not play a role.
Asymmetric transient enhanced intermixing in Pt/Ti
Authors: Süle P. , Menyhárd M. , Kótis L. , Lábár J. , Egelhoff W. F.
Published: February 2007

The ion-sputtering induced intermixing is studied by Monte Carlo transport of ions in matter (TRIM), molecular-dynamics (MD) simulations, and Auger electron spectroscopy depth profiling (AES-DP) analysis in Pt/Ti/Si substrate (Pt/Ti) and Ta/Ti/Pt/Si substrate (Ti/Pt) multilayers. Experimental evidence is found for the asymmetry of intermixing in Pt/Ti, and in Ti/Pt. In Ti/Pt we obtain a much weaker interdiffusion (broadening at the interface) than in Pt/Ti. The unexpected enhancement of the interdiffusion of the Pt atoms into the Ti substrate has also been demonstrated by simulations. We are able to capture the essential features of intermixing using TRIM and MD simulations for ion-beam sputtering and find reasonable values for interface broadening which can be compared with the experimental measurements. We explain the asymmetry of IM by the possible occurrence of transient enhanced diffusion in Pt/Ti which manifests in the exponential high diffusity tail of the AES concentration profile.
Influence of SiO2 dielectric preparation on interfacial trap density in pentacene-based organic thin-film transistors
Authors: Smith J. W. H. , Hill I. G.
Published: February 2007

Organic thin-film transistors were fabricated using SiO2 as the gate dielectric and pentacene as the active layer. Two dielectric preparation methods, solvent cleaning and oxygen plasma cleaning, were used prior to pentacene deposition. The threshold voltage shifts and hysteresis of the saturation transfer characteristics were studied for a large number of devices, and statistically significant differences were identified. The threshold voltage shift between off-to-on and on-to-off sweeps was 13.2±0.6 V for solvent cleaned devices, and 4.4±0.2 V for plasma cleaned devices. The improvement is attributed to the reduction in organic contamination at the semiconductor/dielectric interface following plasma cleaning, and a corresponding reduction in both hole and electron interfacial trapping states.
Effect of an error field on the stability of the resistive wall mode
Authors: Fitzpatrick Richard
Published: February 2007

A simple model of the resistive wall mode (RWM) in a rotating tokamak plasma subject to a static error field is constructed, and then used to investigate RWM stability in a DIII-D–like [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] plasma. An error field as small as 10 G (i.e., about 5×10−4 of the toroidal field) is found to significantly increase the critical plasma rotation frequency needed to stabilize the RWM. Such an error field also profoundly changes the nature of the RWM onset. At small error-field amplitudes, the RWM switches on gradually as the plasma rotation is gradually reduced. On the other hand, at large error-field amplitudes, there is a sudden collapse of the plasma rotation as the rotation frequency falls below some critical value. This collapse is associated with a very rapid switch-on of the RWM.
Controlled fabrication of nanopit patterns on a graphite surface using focused ion beams and oxidation
Authors: Ghaleh F. , Köster R. , Hövel H. , Bruchhaus L. , Bauerdick S. , Thiel J. , Jede R.
Published: February 2007

We produced nanopits on a highly oriented pyrolytic graphite substrate arranged in a given pattern with a combination of focused ion beam (FIB) irradiation and an oxidation process. The FIB irradiation was carried out using a dedicated FIB nanofabrication tool [J. Gierak et al., Appl. Phys. A: Mater. Sci. Process. A80, 187 (2005)]. After oxidation of the sample surface, defects produced by single ions were imaged as one monolayer deep nanopits with scanning tunneling microscopy. The penetration depth of the ions could be measured by oxidation of the defective volume produced on points irradiated with high ion doses. An array of well separated nanopits with a periodicity of 50nm could be produced.
Online system for temperature and accumulated dose control in plasma-based ion implantation
Authors: Roy F. , Abel G. , Terreault B. , Reguer A. , Meunier J.-L. , Bolduc M. , Ross G. G.
Published: February 2007

Surface treatment optimization requires the control of the ion dose and the workpiece temperature, two parameters that are not trivially measurable in plasma-based ion implantation. A temperature and ion fluence monitoring system has been developed and implemented in a plasma-based ion implanter. It is based on the measurement with a thermopile of the radiation emitted from the back face of a thin copper disk inserted in the stainless steel sample holder. Since the incident ions carry practically all the incident power, the measurement of the Cu disk temperature that increases during implantation can provide an evaluation of the ion fluence in real time. A model has been developed for the deconvolution of the temperature data and has been fitted to the temperature behavior during implantation. A good agreement between the total integrated doses, evaluated with Rutherford backscattering spectroscopy characterization, and the ion fluence calculated by means of this model has been obtained with a discrepancy less than 16%.
Enhanced dielectric and ferroelectric properties of Pb(Zr0.8Ti0.2)O3∕Pb(Zr0.2Ti0.8)O3 multilayered thin films prepared by rf magnetron sputtering
Authors: Wu J. G. , Xiao D. Q. , Zhu J. G. , Zhu J. L. , Tan J. Z. , Zhang Q. L.
Published: February 2007

The Pb(Zr1−xTix)O3 multilayered films consisting of Pb(Zr0.8Ti0.2)O3 and Pb(Zr0.2Ti0.8)O3 layers were deposited on LaNiO3(110)∕Pt∕Ti∕SiO2∕Si substrates by rf magnetron sputtering. All films comprise five periodicities, the layer thicknesses of rhombohedral (dR) and tetragonal (dT) phases in one periodicity are varied. The LaNiO3 buffer layer leads to the (101)∕(110) orientation of the films. The electrical properties of the films were investigated as a function of dR∕dT. The films with dR∕dT=1:2 possess enhanced dielectric and ferroelectric properties. The mechanism of the enhanced electrical properties was discussed, and it was found that the strain is also an important factor to affect electrical properties.
Excess densities and equimolar surfaces for spherical cavities in water
Authors: Floris Franca Maria
Published: February 2007

For hard spheres with a radius up to 10Å in TIP4P water under ambient conditions, the author studies how the excess number of molecules at the accessible surface depends on the radius of the cavity. Simulation results derived from excess volumes are discussed in terms of radial distribution functions (rdfs), which compare well with extended simple point charge and theoretical rdfs from the literature. The excess number of molecules at the accessible surface inserted in the expression which refers to an arbitrary dividing surface enables one to find the position of the equimolar surface. The surface tension corresponding to this dividing surface was obtained from values of the free energy of cavity formation. For radii in the range of the simulation data, its behavior with curvature is quite different from that usually shown in the literature. A model, which describes how the excess number of molecules at the accessible surface changes with the radius, is discussed in the large length limit by examining consistent rdfs described by a simple analytical form. The inclusion in the model of a logarithmic term has also been considered. Comparison with theoretical results from the literature shows a good agreement for a cavity with a radius of 20Å. For a radius of 100Å and beyond, the model predicts instead sharper density profiles. Such differences have a poor effect on the surface tension at the equimolar surface.
Relativistic and nonrelativistic solutions for diatomic molecules in the presence of double ring-shaped Kratzer potential
Authors: Durmus Aysen , Yasuk Fevziye
Published: February 2007

The authors investigate solutions of the three dimensional Klein-Gordon and Schrödinger equations in the presence of a new exactly solvable potential of V(r,θ)=−2De(re∕r−(1∕2)(re2∕r2))+b∕r2sin2θ+a∕r2cos2θ type, the so-called double ring-shaped Kratzer potential. For a diatomic molecule system in double ring-shaped Kratzer potential, the exact bound state energy eigenvalues and corresponding wave functions have been determined within the framework of the asymptotic iteration method. Bound state eigenfunction solutions used in applications related to molecular spectroscopy are obtained in terms of confluent hypergeometric function and Jacobi polynomial. This new formulation is tested by calculating the energies of rovibrational states of a number of diatomic molecules. Also, the author-prove that in the nonrelativistic limit c→∞, where c is the speed of light, solutions of the Klein-Gordon system converge to those of the Schrödinger system.
Testing the Elastic-Cities Concept within a Nonmetropolitan Environment: Evidence from British Columbia, Canada, 1971 to 2001
Authors: Meligrana John
Published: February 2007

In this study I tested the elastic-city hypothesis within a nonmetropolitan environment. Elastic cities are defined as employing aggressive annexation strategies that result in more effective planning control over the city-region, higher population increases, stronger tax bases, and healthier urban-regional economies than those of nonelastic cities. Principal component analysis was used to analyze and model the elasticity of British Columbia's approximately 100 municipal governments for a thirty-year period, 1971–2001. The findings do not completely support the correlation between a municipality's elastic boundary and growth or development. In fact, the picture is more complex than suggested by Rusk's elastic-cities concept. Annexing municipalities do not exhibit stronger population growth, newer dwellings, or economic development when compared with nonannexing municipalities. Annexation may be contributing to rural-urban sprawl rather than more-compact development patterns.
Muji, Materiality, and Mundane Geographies
Authors: Holloway Julian , Hones Sheila
Published: February 2007

This paper is based on the premise that mundanity is not so much a quality inherent in an object or event as an appearance or affordance generated at the intersection of object, subject, and location. Assuming that a single object will appear banal in one context and different in another, we focus our attention on cases in which a single object is encountered as both banal and different—visible and invisible at the same time, marked out by its ability to blend in. In this paper we explore the mundane and distinctive by reference to marketing and products of the Japan-based company Muji, and in particular through relating the two contrasting aspects of the Muji image to the different ways in which the objects are located in presentation-marketing contexts and in wear-use contexts. In order to explore the usefulness of this distinction between display space and use space we perform a tactical erasure of the commonsense distinction between the textual and the material, thereby enabling the collapsing together, into the single category of display space, of the textual spaces of Muji catalogues and the material spaces of Muji shop floors. The distinction between the en-masse presentation of new objects in highly controlled display spaces and the mundane wear and use of purchased objects in the various and variously encountered spaces of everyday life is explored through the hybrid display-use space of Muji show homes known as Muji-Infill. We conclude by proposing that this display-use distinction can be used strategically to articulate the way in which skilled consumers are able to encounter objects imaginatively and practically in two different contexts simultaneously. In other words, we speculate that, when skilled consumers encounter a superficially mundane Muji object in the literal and disorganised context of use space, they are able to recognise it as stylish and desirable in part by referring to an acquired understanding of the ways in which that object-in-use evokes a Muji marketing space of massed objects-on-display.
FXYD1 is an MeCP2 target gene overexpressed in the brains of Rett syndrome patients and Mecp2-null mice
Authors: Deng Vivianne , Matagne Valerie , Banine Fatima , Frerking Matthew , Ohliger Patricia , Budden Sarojini , Pevsner Jonathan , Dissen Gregory A. , Sherman Larry S. , Ojeda Sergio R.
Published: February 2007

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder linked to heterozygous de novo mutations in the MECP2 gene. MECP2 encodes methyl-CpG-binding protein 2 (MeCP2), which represses gene transcription by binding to 5-methylcytosine residues in symmetrically positioned CpG dinucleotides. Direct MeCP2 targets underlying RTT pathogenesis remain largely unknown. Here, we report that FXYD1, which encodes a transmembrane modulator of Na+,K+-ATPase activity, is elevated in frontal cortex (FC) neurons of RTT patients and Mecp2-null mice. Increasing neuronal FXDY1 expression is sufficient to reduce dendritic arborization and spine formation, hallmarks of RTT neuropathology. Mecp2-null mouse cortical neurons have diminished Na+,K+-ATPase activity, suggesting that aberrant FXYD1 expression contributes to abnormal neuronal activity in RTT. MeCP2 represses Fxyd1 transcription through direct interactions with sequences in the Fxyd1 promoter that are methylated in FC neurons. FXYD1 is therefore a MeCP2 target gene whose de-repression may directly contribute to RTT neuronal pathogenesis.
Rapid bioconcentration of steroids in the plasma of three‐spined sticklebackGasterosteus aculeatusexposed to waterborne testosterone and 17β‐oestradiol
Authors: Maunder R. J. , Matthiessen P. , Sumpter J. P. , Pottinger T. G.
Published: February 2007

The relationship over time between the concentrations of two steroids, singly and in combination, in a static exposure system and in the blood of three‐spined sticklebackGasterosteus aculeatus, held within the exposure system was investigated. Groups of three‐spined stickleback were exposed (nominally) to either 1000 ng l−117β‐oestradiol (E2), testosterone (T) or E2 and T in combination at the same concentrations for 6 days. Both water and fish were sampled at intervals and steroid concentrations in both compartments were determined. The plasma steroid time profile revealed a rapid bioconcentration within the first 6 h of exposure. The plasma steroid levels attained at this time point (20–90 ng ml−1) were up to 50‐fold (E2) and 200‐fold (T) greater than the actual levels of steroid measured in the exposure water, while levels in the blood of control fish did not exceed 4 ng ml−1. The substantial elevation of plasma steroid levels relative to the concentrations of steroid to which the fish were exposed in the ambient water gives scope for delivery of the steroids to target endocrine tissues at levels far in excess of what might be predicted on the basis of passive branchial uptake alone. These results are discussed in relation to endocrine disruption, and in particular the occurrence of effects in fish exposed to levels of endocrine active substances that are seemingly physiologically irrelevant.
The effectiveness of two common sampling methods for assessing imperilled freshwater fishes
Authors: Poos M. S. , Mandrak N. E. , McLaughlin R. L.
Published: February 2007

This study tested the hypothesis that the most common gear type used to sample fishes in wadeable systems, electrofishing, was more effective than another commonly used gear type, seining, for sampling fish species at risk. Five predictions were tested. At sites where species at risk were detected, (1) the probability of detecting the species at risk, (2) the probability of only one gear type detecting the species at risk and (3) the estimated catch per unit effort of the species at risk, was as high as, or higher, when using electrofishing than when using a seine. (4) The number of sample sites required to detect a species at risk within a watershed and (5) the number of subsections required to detect a species at risk within a site, were as low as, or lower, using electrofishing than the number required using a seine. Based on analyses of these measurements, electrofishing was a more effective gear type than seining for sampling fish species at risk, irrespective of the unit (presence or absence or catch per unit effort) or scale of measurement (watershed or site level). Dissolved oxygen, turbidity, specific conductivity and nitrate concentrations were measured at each site and did not account for the between gear differences. Selection of sampling gear can be a fundamental consideration for the assessment of fish species at risk, where, unlike common species, they may be particularly influenced by small population sizes, restricted geographic ranges and narrow habitat preferences. Resource managers must weigh differences in the risks of injury of fish species at risk against differences in the effectiveness of each gear type when deciding between gear types and the utility of the assessments they represent.
Relationship between fertilization success and the number of milt donors in rainbow smelt Osmerus mordax (Mitchell): implications for population growth rates
Authors: Purchase C. F. , Hasselman D. J. , Weir L. K.
Published: February 2007

A series of artificial fertilizations using rainbow smelt Osmerus mordax were conducted, each designed to assess the fertilization success of a female’s eggs with milt from one to five males. Mean egg fertilization success increased and variance in fertilization success decreased when more males contributed to a constant volume of milt. This may indicate the presence of an Allee effect. The results suggest that potential changes in egg fertilization success due to a decrease in the number of males, in addition to changes in egg production due to a decrease in the number of females, can affect estimates of maximum sustainable harvest rates, and recovery of depleted populations.
Role of habitat in mediating mortality during the post‐settlement transition phase of temperate marine fishes
Authors: Juanes F
Published: February 2007

The transition phase describes a distinct post‐settlement stage associated with the recruitment to benthic habitats by pelagic life stages. The habitat shift is often accompanied by feeding shifts and metamorphosis from larval to juvenile phases. Density‐dependent settlement, growth and mortality are often the major factors controlling recruitment success of this phase. Habitat use also becomes more pronounced after settlement. The role of habitat‐mediated post‐settlement mortality is elucidated by focusing on the early life history of Atlantic cod (Gadus morhua) and cunner (Tautogolabrus adspersus) in the north‐west Atlantic. In these species, settlement can occur over all bottom types, but habitat‐specific differences in post‐settlement mortality rates combined with size and priority at settlement effects on growth and survival determine recruitment and eventual year‐class strength. These results and those from other temperate marine fish species along with work on tropical reef species emphasize the generality of habitat‐based density‐dependent mortality during the transition phase and its potential for population regulation. These results have implications for fisheries management and can be used to outline a procedure to assist managers in identifying and managing essential transitional habitats including the potential role of marine protected areas in habitat conservation.