bluuebunny/crossref_metadata_2025 huggingface dataset:
Silicon Nanoparticle Formation in Si+-Implanted Thermal Oxide Films and Visible Photoluminescence Behavior
Authors: Shimizu-Iwayama Tsutomu , Nakao Setsuo , Saitoh Kazuo
Published: March 2014

We have investigated optical properties and microstructures of Si+-implanted thermal oxide films grown on crystalline Si wafer, as-implanted and after subsequent annealing. We found two types of visible luminescence bands similar to those of silica glasses: one peaked around 2.0 eV, observed in as-implanted specimens and annealed completely at about 600 °C, and the other peaked around 1.7 eV, observed only after heating specimens to about 1100 °C, the temperature at which Si segregates from SiO
x
. Though the shapes of these luminescence spectra are quite different from those having been observed in Si+-implanted silica glasses caused by interferences, the origins of these bands are the same as in silica glasses. Moreover, the direct evidence for the formation of nanometer-sized Si crystals in amorphous silicon dioxide matrix after annealing at 1100 °C is presented by high-resolution transmission electron microscopy.
Photoluminescence from Silicon Quantum Crystallites: Core and Surface States
Authors: Kanemitsu Yoshihiko , Uto Hiroshi , Matsumoto Takahiro
Published: March 2014

We report nonlinear luminescence properties of oxidized silicon nanociystallites and porous silicon. Under intense laser pulse illumination, two photoluminescence (PL) bands are clearly observed: a fast-decay blue-green PL band and a slow-decay red PL band. Spectroscopic analysis suggests that the slow-decay red PL is caused by the hoppinglimited recombination process in the surface localized state of the nanociystallite, while the blue-green PL is caused by the band-edge emission from the core state of the nanociystallite.
Surface Structural Relaxation of Silica Glasses
Authors: Tomozawa Minoru , Peng Yih-Lih , Agarwal Anand
Published: March 2014

The surface of a glass is expected to have structure and properties different from those of the bulk. The structural state of the silica glass surface is important in determining a variety of silica properties, such as the mechanical and chemical properties of optical fibers and the electrical and optical properties of thin silica films. In general, the structural state of a glass changes with time through the relaxation process. Our results indicate that the surface relaxation takes place much more rapidly than the bulk relaxation. Furthermore, unlike the bulk relaxation, the surface relaxation was promoted by water vapor and an applied tensile stress. It is suggested that the surface structural relaxation promoted by water vapor and tensile stress may be a mechanism of the mechanical fatigue of silica glasses. Two different modes of surface relaxation appear to exist under a constant external condition.
One Photon and Two Photon Process in Photo-Decomposition of Germanium Oxygen Deficient Centres
Authors: Dong L. , Bagratashvili V. N. , Tsypina S. I. , Zavorotny Y. S. , Rybaltovskii A. O. , Chernov P. V. , Alimpiev S. S. , Simanovskii Y. O.
Published: March 2014

UV photon-induced transformation of germanium oxygen deficient centres (GODC) in germanium-doped silica glass have been studied using photocurrent measurements, absorption and fluorescence bleaching. It has been identified that the photocurrent are generated via a two photon effect. Evidence have been found suggesting that the UV photon-induced destruction of GODCs is achieved via two reaction pathways, a single photon pathway and a two photon pathway. The process is discussed.
Aspects of Resonant Enhancement of Nonlinear Optical Properties in Silica
Authors: Haus Joseph W.
Published: March 2014

This paper briefly reports two approaches toward improving the nonlinear response of glassy materials. Recent results demonstrate that the use of local-field resonance or Bragg interference effects provide improved figures of merit.
Light Scattering Studies on the Glass Transition and the Structure in Silica Glass
Authors: Saito K. , Kakiuchida H. , Ikushima A. J.
Published: March 2014

Peculiar properties in silica glass were investigated by the light scattering measurements. It was shown that the glass transition temperature can well be determined by measuring temperature dependence of the light scattering intensity. Relations between the glass transition temperature, the fictive temperature, cooling rate, and viscosity were clarified in low and high OH-containing silica glasses, and the effect of OH ions on the slow dynamics was revealed. On the processes of supercooled liquid\leftrightarrowsliquid, the light scattering intensity was found to change drastically at a melting temperature of cristobalite. This result strongly suggests that medium-range order structures, microcrystallites, exist in silica glass.
Reliability and Environmental Stability of Polymer based Solid State Optical Switches
Authors: Donckers Marc C. J. M. , Jr. Thomas A. Tumolillo, , Dobbelaere Peter M. C. De , Flipse Marinus C. , DIemeer Mart B. J. , Zhu Ning , Lipscomb George F.
Published: March 2014

The development of reliable and environmentally stable photonic space switches based on the BeamBoxáTM Solid State Optical Switch technology is described. The realization of a robust temperature stable (-40°C to 75°C) fiber pigtail attachment joint is presented.
Erasing Process of Thermally Poled Optical Nonlinearities in Silica Glasses with KrF Excimer Laser Pulses
Authors: Kameyama Akihiro , Kurosawa Kou , Yokotani Atsushi
Published: March 2014

We observed a second-order optical nonlinearily of χ33
(2)=Q.30 pm/V in a fused silica glass poled under the condition of static electric field of 4 kV/mm at 260°C. The nonlinearity layer localized in the surface region contacted on the positive electrode during poling in a thickness comparable with or thinner than the interaction length of 22 µm. Even though a nonlinearity phase formation was not observed in synthetic silica glass under the same condition, the poling induced a nonlinearity of 0.24 pm/V by exposing the sample to X-ray radiation before poling. We also observed that 248-nm pulses as low as 10 mJ/cm2 from a KrF excimer laser erased the nonlinearity.
Luminescence Properties of Cerium (III) in Silica Glass Prepared by the Sol-Gel Process
Authors: Sekine Nobuhiro , Ueda Tetsuya , Matsui Kazunori
Published: March 2014

The absorption spectra for Ce-doped sols from tetramethoxysilane showed that most Ce3+ existed as [Ce(OH2)9]+. The luminescence of Ce3+ exhibited a peak around 360 nm for aqueous solutions and sols, indicating that the emissive species is [Ce(OH2)8]3+ mainly produced from photodissociation of [Ce(OH2)9]3+. The absorption and emission spectra for xerogels aged 6 month were virtually the same as those of solutions, meaning that the same phenomenon occurs for xerogels. Longer wavelength emission was also observed, particularly for basic xerogels, possibly due to Ce3+ associated with Ce4+.
Photosensitive Thin Films: Manipulation of Defects Through Synthesis Control
Authors: Simmons-Potter Kelly , Jr. Barrett Potter, , Sinclair Michael
Published: March 2014

Multi-functional, integrated optical devices are the foundation for technologies commanding a significant high-tech market share. Areas such as telecommunications, remote sensing, biomedical applications, information processing and data storage benefit from devices based on the patterning of refractive index modulations. Current synthesis techniques used to achieve the desired device structures typically involve multi-step processing, relying on complex chemical and/or mechanical procedures. We have demonstrated the ability to produce highly photosensitive germanosilicate thin films using a novel sputtering approach which enables us to obtain the largest reported Δn in as-synthesized materials. In addition, control of processing environment has allowed us to engineer not only the magnitude of the optical response of the films but also the sign of the induced index change. We have developed a defect model to describe the effects observed and have demonstrated proof-of-principle devices in our waveguides.
Josephson Effect and Radiation Detection
Authors: Pagano Sergio
Published: March 2014

Josephson junctions are considered as possible candidates for fast nuclear particle detection. The mechanisms of interaction between ionizing particles and Josephson junctions are briefly discussed. Three examples of possible implementations of fast Josephson detectors are discussed in some details.
Review of Series-Connected Superconducting Tunnel Junction Detectors and Their Future Perspectives
Authors: Kurakado Masahiko
Published: March 2014

Series-connected superconducting tunnel junctions have high potentialities as radiation detectors with ultra-high energy resolutions, high count-rates, and high detection efficiencies. Series-junction detectors consisting of multiple series-junctions can detect incident positions of radiations. The position information, e.g., resolution of 35 µm in a region of 3.2 mm2, improves the energy resolution of the detectors. A series-junction detector has shown much splendid characteristics: two order fewer tail signals, no double peaks, no phonon signals lower than peak, higher linearity of signal height to radiation energy, and much higher absorption efficiency, when compared with superconducting single-junction detectors. Series-junction detectors will be utilized to measure high energy radiations as well as low energy X rays. In the present paper, our studies on series-junction detectors are reviewed and future perspectives of the detectors are presented.
Quantitative Evaluation of the Quantum Efficiency of a Superconducting Tunnel Junction with the Multiple Scattering Process Model of Primary Photoelectrons
Authors: Ukibe Masahiro , Kishimoto Maki , Katagiri Masaki , Kurakado Masahiko , Nakamura Tatsuya , Nakazawa Masaharu
Published: March 2014

The electron multiple scattering process of primary photoelectrons generated absorbed X-rays was studied so as to developed a clear model of a signal producing process of a STJ, and the intrinsic peak efficiency P
1 of the STJ was calculated as a function of X-ray energy. X-rays of 5 to 18 keV were measured by a 178 µm×178 µm Nb/Al-AlO2/Al/Nb superconducting tunnel junction with a Nb-electrode, 200nm thickness and the P
1 agreed well with the measured one in X-ray energy range of 5 to 12 keV.
Injection-Detection Experiments to Study Diffusion Processes in Nb film using a Three Terminal in-plane Superconducting Double-Tunnel Junctions
Authors: Parlato Loredana , Ammendola Giuseppe , Peluso Giuseppe , Pepe Giovanni Piero , Esposito Emanuela , Nakagawa Hiroshi , Akoh Hiroshi , Takada Susumu
Published: March 2014

Superconducting Tunnel Junctions are promising devices in next generation nuclear and optical detectors. Unfortunately, a number of relaxation processes in the number of initially produced excitations degrades the performances of such devices. In order to investigate the role of charge loss mechanisms in Nb and/or at the Nb/Si interface we have fabricated three terminal in-plane double tunnel junctions, in which quasi-particles are injected into a Nb common strip and detected at different distances by tunnel junctions. The detection efficiency η decreases of about one order of magnitude from T=4.2K to T=1.2K for any injector-detector distance. The presence of charge trapping centers, activated at low temperatures, can qualitatively explain such a result. The estimation of the quasi-particle diffusion constant D=28±5 cm2/s at T=1.2 K is in agreement with other similar values reported in literature.
Annual variations in westward auroral electrojet and substorm occurrence rate during solar cycle 23
Authors: Guo Jianpeng , Pulkkinen T. I. , Tanskanen E. I. , Feng Xueshang , Emery Barbara A. , Liu Huixin , Liu Chaoxu , Zhong Dingkun
Published: March 2014

The International Monitor for Auroral Geomagnetic Effects network magnetic measurements during the period 1995–2009 are used to characterize the annual variations in the westward electrojet. The results suggest that the annual variations in different local time sectors are quite different due to the different sources. In the MLT sector 2200–0100, the annual variations with maxima in winter suggest they are caused by the combined effects of the convective electric field and the conductivity associated with particle precipitation. Furthermore, the conductivity seems to play a more important role in the MLT sector ∼2200–2320, while the convective electric field appears to be more important in the MLT sector ∼2320–0100. In the MLT sector 0300–0600, the annual variations with maxima in summer suggest they are caused by solar EUV conductivity effect and the equinoctial effect. The solar EUV conductivity effect works by increasing ionospheric conductivity and enhancing the westward electrojet in summer, while the equinoctial effect works by decreasing solar wind‐magnetosphere coupling efficiency and weakening the westward electrojet in winter. In the MLT sector 0100–0300, the annual variations are relatively weak and can be attributed to the combined effects of annual variations caused by all the previously mentioned effects. In addition, we find that a significant annual variation in substorm occurrence rate, mainly occurring in the premidnight region, is quite similar to that in the westward electrojet. We suggest that elevated solar wind driving during the winter months contributes to higher substorm occurrence in winter in the Northern Hemisphere.
Seismic constraints of the formation process on the back‐arc basin in the southeastern Japan Sea
Authors: Sato Takeshi , No Tetsuo , Kodaira Shuichi , Takahashi Narumi , Kaneda Yoshiyuki
Published: March 2014

To clarify the formation process of the back‐arc basin in the Japan Sea, which is located next to the northwestern Pacific, a seismic survey using ocean bottom seismographs and an air gun array was undertaken in areas from the northern Yamato Basin to the coast of the northeastern Japan Island Arc off Awa‐shima Island. The crust beneath the northern Yamato Basin off Awa‐shima Island is approximately 16 km thick. The upper and lower crusts are, respectively, about 5 km thick with a steep velocity gradient and about 10 km thick with a gentle velocity gradient. In the basin, there are very few units with P wave velocity of 5.4–6.0 km/s, corresponding to the continental upper crust. The crustal structure of the northern Yamato Basin has characteristics of thicker oceanic crust. The high‐velocity lowermost crust in the northern Yamato Basin with 7.2–7.4 km/s might show melt formed by a slightly high mantle temperature during the opening of the basin. However, the crust beneath the areas from the Sado Ridge to the coast, which is approximately 25–26 km thick, is slightly thinner than that of the continental crust and island arc crust. The crustal structure beneath this area is inferred to be a rifted continental and/or a rifted island arc crust.
Frictional response to velocity steps and 1‐D fault nucleation under a state evolution law with stressing‐rate dependence
Authors: Bhattacharya P. , Rubin A. M.
Published: March 2014

A new state evolution law has recently been proposed by Nagata et al. (2012) that includes a dependence upon stressing rate through a laboratory derived proportionality constant c. It has been claimed that this law, while retaining the time‐dependent healing of the Dieterich (or Aging) law, can also match the symmetric response of the Ruina (or Slip) law to velocity step tests. We show through analytical approximations and numerical results that the new law transitions between the responses of the traditional Aging and Slip laws in velocity step‐up/step‐down experiments when the value of c is tuned properly. Particularly, for c=0, the response is pure Aging, while for finite, nonzero c one observes Slip law type behavior for small velocity jumps but Aging law type response for larger jumps. The magnitude of the velocity jump required to see this transition between aging and slip behaviors increases as c increases. In the limit of c≫1 the response becomes purely Slip law type for all geologically plausible velocity jumps. We also present results from detailed analytical and numerical studies of the mechanism of rupture nucleation on 1‐D faults under this new state evolution law to demonstrate that the style of nucleation can also be made to switch from Aging‐type (expanding cracks) to Slip‐type (slip pulses) by adjusting the value of c as indicated by the velocity step results.
How do consumers infer corporate social responsibility? The role of organisation size
Authors: Green Todd , Peloza John
Published: March 2014

Consumers are generally supportive of firms that engage in corporate social responsibility (CSR) activities. However, consumers are also largely unaware of CSR activities of firms and often use available information to infer CSR. The current study utilises in‐depth consumer interviews to explore the influence of firm size on consumer perceptions of both CSR and corporate socially irresponsible behaviour through the lens of attribution theory. We identify two key emerging antecedents – consumer trust and expectations for CSR engagement – that are influenced by organisation size and ultimately distinguish the types of attributions consumers hold towards CSR and corporate socially irresponsible behaviour. Specifically, consumers have greater levels of trust and significantly lower expectations for CSR engagement for small firms. Conversely, a lack of trust exists amongst consumers towards large firms along with greater expectations for CSR engagement. Although the interview findings generally suggest that small firms benefit from CSR engagement because of positive attributions that consumers hold, we also identify opportunities for large firms to develop positive attributions amongst consumers. Further, we find that consumers are often willing to accept socially irresponsible behaviour by small firms whereas showing very little tolerance for similar transgressions by large firms. Copyright © 2014 John Wiley & Sons, Ltd.
Fuzzy Modeling of the Permeate Flux Decline during Microfiltration of Starch Suspensions
Authors: Ikonić Bojana B. , Takači Aleksandar A. , Zavargo Zoltan Z. , Šereš Zita N. , Šaranović Žana V. , Ikonić Predrag M.
Published: March 2014

Flux declines versus time during cross‐flow microfiltration of wheat starch suspensions were modeled using fuzzy logic systems under different conditions of transmembrane pressure, flow rate, and suspension concentration. Fuzzy modeling is one of the most efficient methods for empirical modeling, especially for non‐linear systems, and does not require any prior knowledge about the process. The influence of the process parameters on the dynamic behavior of the permeate flux was determined by comparing the permeate flux decline versus the volume curves, considering a constant value of the volumetric concentration factor during batch cross‐flow filtration. At the transient stages of the filtration process, the permeate flux was shown to be strongly dependent on all process parameters, within the examined range.
Impact of Surfactant Chemistry on Bubble Column Systems
Authors: McClure Dale D. , Deligny Julien , Kavanagh John M. , Fletcher David F. , Barton Geoffrey W.
Published: March 2014

The impact of surfactant addition on the overall holdup, drag coefficient, and bubble size distribution (BSD) in a bubble column operating at industrially relevant superficial velocities was analyzed. A range of surfactants was examined, including alcohols, sugars, and antifoaming agents. It was ascertained that the effect of a surfactant on the holdup and BSD could be related to the chemical structure of the compound, specifically its hydrophilic/hydrophobic nature as characterized by the octanol/water partition coefficient. Addition of 2‐propanol to an air/water system induces a behavior similar to the fermentation media used in aerobic bioprocesses, meaning that such a system can be applied as a meaningful physical analogue in pilot‐scale experimentation.
A new multiobjective procedure for solving nonconvex environmental/economic power dispatch
Authors: Morsali Roozbeh , Mohammadi Mohsen , Maleksaeedi Iman , Ghadimi Noradin
Published: March 2014

In this article, an improved multiobjective chaotic interactive honey bee mating optimization (CIHBMO) is proposed to find the feasible optimal solution of the environmental/economic power dispatch problem with considering operational constraints of the generators. The three conflicting and noncommensurable: fuel cost, pollutant emissions, and system loss, should be minimized simultaneously while satisfying certain system constraints. To achieve a good design with different solutions in a multiobjective optimization problem, Pareto dominance concept is used to generate and sort the dominated and nondominated solutions. Also, fuzzy set theory is used to extract the best compromise solution. The propose method has been individually examined and applied to the standard Institute of Electrical and Electronics Engineers (IEEE) 30‐bus six generator, IEEE 180‐bus 14 generator and 40 generating unit (with valve point effect) test systems. The computational results reveal that the multiobjective CIHBMO algorithm has excellent convergence characteristics and is superior to other multiobjective optimization algorithms. Also, the result shows its great potential in handling the multiobjective problems in power systems. © 2014 Wiley Periodicals, Inc. Complexity 20: 47–62, 2014
Ultimate bound sets of a hyperchaotic system and its application in chaos synchronization
Authors: Nik Hassan Saberi , Effati Sohrab , Saberi‐Nadjafi JAFAR
Published: March 2014

In this article, we investigate globally exponentially attractive sets and chaos synchronization for a hyperchaotic system, namely, Lorenz–Stenflo system. For this system, two ellipsoidal globally exponentially attractive sets are derived based on generalized Lyapunov function theory and the extremum principle of function. Furthermore, we propose linear feedback control with a one, two, three, and four inputs to realize globally exponential synchronization of two four‐dimesional hyperchaotic systems using inequality techniques. Numerical simulations are presented to show the effectiveness of the proposed synchronization scheme. © 2014 Wiley Periodicals, Inc. Complexity 20: 30–44, 2015
Dissonance‐based prevention of eating disorder risk factors in middle school girls: Results from two pilot trials
Authors: Rohde Paul , Auslander Beth A. , Shaw Heather , Raineri Kate M. , Gau Jeff M. , Stice Eric
Published: March 2014

Objective

Although several eating disorder prevention programs reduce eating disorder risk factors and symptoms for female high school and college students, few efficacious prevention programs exist for female middle school students, despite the fact that body image and eating disturbances often emerge then. Two pilot trials evaluated a new dissonance‐based eating disorder prevention program for middle school girls with body image concerns.

Method

Female middle school students with body dissatisfaction from two sites [Study 1: N = 81, M age = 12.1, standard deviation (SD) = 0.9; Study 2: N = 52, M age = 12.5, SD = 0.8] were randomized to a dissonance intervention (MS Body Project) or educational brochure control; Study 2 included a 3‐month follow‐up.

Results

Intervention participants showed significant post‐test reductions in only one of the six variables with both Studies 1 and 2 (i.e., pressure to be thin and negative affect, respectively), though post‐test effect sizes suggested medium reductions in eating disorder risk factors and symptoms (Study 1: M d = .40; Study 2: M d = .65); reductions at 3‐month follow‐up in Study 2 were not evident (M d = .19).

Conclusions

Results suggest that this new middle school version of the Body Project is producing medium magnitude reductions in eating disorder risk factors at post‐test but that effects are showing limited persistence. Continued refinement and evaluation of this intervention appears warranted to develop more effective prevention programs for this age group. © 2014 Wiley Periodicals, Inc. (Int J Eat Disord 2014; 47:483–494)
Detection of Cells State‐of‐Health in PEM Fuel Cell Stack Using EIS Measurements Coupled with Multiphysics Modeling
Authors: Chevalier S. , Auvity B. , Olivier J. C. , Josset C. , Trichet D. , Machmoum M.
Published: March 2014

This paper presents a pseudo 2D multiphysics A.C. and D.C. model that has been successfully used with Electrochemical impedance spectroscopy (EIS) measurements to detect cells state‐of‐health in a PEMFC stack. The model is able to reproduce the gas concentration oscillations that develop along the cell channel while doing EIS measurements. This feature makes it possible to explicitly take into account the air stoichiometry effects on cells state‐of health. The model being both static and harmonic, the identification of model parameters is based on static cell data (current and voltage) and on measured cells impedance spectra. The cells state‐of‐health is presented in terms of repartition of losses due to four limiting phenomena: the membrane ionic resistance, the mass and charge transport limitations in the electrode, the mass transport limitations through GDLs and along the cell channels and the kinetic irreversibilities. When coupled with pressure drop measurements across the stack, it has been possible to prove that flooding conditions for the stack leads to inhomogeneous cells state‐of‐health: on one hand, most of the cells get flooded while, on the other hand, some of them remain in the nominal conditions.
Impact of arbuscular mycorrhizal fungi on the growth and expression of gene encoding stress protein – metallothionein BnMT2 in the non‐host crop Brassica napus L.
Authors: Dąbrowska Grażyna , Baum Christel , Trejgell Alina , Hrynkiewicz Katarzyna
Published: March 2014

Arbuscular mycorrhizal (AM) fungi are an important component of the soil biota in most agroecosystems, and their association can directly or indirectly affect the diversity of soil microorganisms, nutrient cycling, and growth of host plants. Since not all crops are symbiotic, we hypothesized that the presence of AM fungi can: (1) inhibit the growth of non‐host plants by resulting in biotic stress, or (2) promote their growth indirectly by increased nutrient mobilization. These hypotheses were tested in the present study on the non‐mycorrhizal crop canola (Brassica napus L.) in the presence and absence of other autochthonous soil microorganisms. The soil was inoculated with a mixture of AM fungi (Acaulospora longula, Glomus geosporum, G. mosseae, Scutellospora calospora) and as a control, a non‐inoculated soil was used. The impact of inoculation on plant growth (biomass production, nutrient concentrations) and expression of the stress protein metallothionein gene BnMT2 was investigated in the shoots. B. napus L. did not form mycorrhizal associations on its roots, but its growth was promoted after inoculation with AM fungi. In the soil with autochthonic microorganisms, growth inhibition after inoculation was observed compared to the control. The concentrations of N, P, K, and S in the shoot were always significantly increased after inoculation with AM fungi. However, this was partly combined with reduced growth and thereby decreased total uptake of nutrients. Expression of BnMT2 in the leaves was increased after inoculation with AM spores at the soil devoid of indigenous microorganisms, but decreased in their presence. The expression of stress proteins (BnMT2) significantly increased with increasing length and biomass of shoots.

In conclusion, the inhibition of the non‐host plant B. napus L. following inoculation with AM fungi was confirmed, however, only in combination with autochthonous microorganisms. Growth promotion of B. napus L. in the presence of AM fungi in the absence of autochthonous soil microorganisms suggest that plant growth depression in the presence of AM fungi was based on interactive effects of AM fungi with the autochthonous microorganisms in the soil rather than on a direct impact of the AM fungi.
High temperature corrosion beneath nitrate melts
Authors: Spiegel M. , Mentz J.
Published: March 2014

Different alloys from ferritic‐martensitic, austenitic, and nickel‐based were exposed beneath a 60%NaNO3–40%KNO3 eutectic mixture in air for 500 h at 600 °C in order to estimate the corrosion loss of the different classes of alloys and to evaluate the corrosion mechanism. Investigations were carried out by metallography, SEM with EDX, and microprobe analysis. Ferritic‐martensitic materials (P 92) show a significant mass gain compared to austenitic material (304 HCu) and nickel‐based alloys. In particular Alloy 617 B suffers from pitting corrosion comparable to sulfate induced hot corrosion. The occurrence of internal nitridation is not clear and has to be evaluated.
Density functional theory studies of Si36H36 and C36H36 nanocages
Authors: Li Jun , Bai Hongcun , Yuan Nini , Wu Yuhua , Ma Yujia , Xue Ping , Ji Yongqiang
Published: March 2014

This work presents systematic studies of the possible classical structures of Si36H36 and C36H36 nanocages using density functional theory calculations. The computed structures, relative stabilities, and electronic properties of these silicon‐ and carbon‐based hydrides are investigated and compared. The results indicate that none of the Si36H36 or C36H36 nanocages exhibit a perfect spherical shape. Hydrogenated nanocages with higher number of adjacent pentagons are more stable and this observation is contrary to the trend of bare fullerenes. The hydrogenated small cages are energetically more favorable than large ones according to the obtained binding energies. Moreover, the energy levels, distributions, and irreducible representations of the frontier orbital for Si36H36 and C36H36 nanocages are also explored. Obvious localizations within the inner space of nanocages are detected for the lowest unoccupied molecular orbital of C36H36. © 2014 Wiley Periodicals, Inc.
A high‐capacity and low‐distortion 3D polygonal mesh steganography using surfacelet transform
Authors: Kaveh Hadi , Moin Mohammad‐Shahram
Published: March 2014

Steganography is the science and art of communicating secret data in an appropriate multimedia cover. Steganography's ultimate concerns are undetectability, robustness, and capacity of data hiding. Three‐dimensional (3D) meshes have been used more and more in industrial, medical, and entertainment applications during the last decades. In this paper, a high‐capacity and very‐low‐distortion 3D mesh steganography scheme based on novel directional N‐dimensional surfacelet transform is proposed. Experimental results show that the cover model distortion is very low. This novel approach can provide a much higher hiding capacity and lower distortion than existing approaches in the transform domain, at the same time, observing the main steganographic factors on 3D models. Copyright © 2014 John Wiley & Sons, Ltd.
Kaolin‐induced ventriculomegaly at weaning produces long‐term learning, memory, and motor deficits in rats
Authors: Williams Michael T. , Braun Amanda A. , Amos‐Kroohs Robyn M. , McAllister James P. , Lindquist Diana M. , Mangano Francesco T. , Vorhees Charles V. , Yuan Weihong
Published: March 2014

Ventriculomegaly occurs when there is imbalance between creation and absorption of cerebrospinal fluid (CSF); even when treated, long‐term behavioral changes occur. Kaolin injection in the cisterna magna of rats produces an obstruction of CSF outflow and models one type of hydrocephalus. Previous research with this model shows that neonatal onset has mixed effects on Morris water maze (MWM) and motoric performance; we hypothesized that this might be because the severity of ventricular enlargement was not taken into consideration. In the present experiment, rats were injected with kaolin or saline on postnatal day (P)21 and analyzed in subgroups based on Evan's ratios (ERs) of the severity of ventricular enlargement at the end of testing to create 4 subgroups from least to most severe: ER0.4–0.5, ER0.51–0.6, ER0.61–0.7, and ER0.71–0.82, respectively. Locomotor activity (dry land and swimming), acoustic startle with prepulse inhibition (PPI), and MWM performance were tested starting on P28 (122 cm maze) and again on P42 (244 cm maze). Kaolin‐treated animals weighed significantly less than controls at all times. Differences in locomotor activity were seen at P42 but not P28. On P28 there was an increase in PPI for all but the least severe kaolin‐treated group, but no difference at P42 compared with controls. In the MWM at P28, all kaolin‐treated groups had longer path lengths than controls, but comparable swim speeds. With the exception of the least severe group, probe trial performance was worse in the kaolin‐treated animals. On P42, only the most severely affected kaolin‐treated group showed deficits compared with control animals. This group showed no MWM learning and no memory for the platform position during probe trial testing. Swim speed was unaffected, indicating motor deficits were not responsible for impaired learning and memory. These findings indicate that kaolin‐induced ventriculomegaly in rats interferes with cognition regardless of the final enlargement of the cerebral ventricles, but final size critically determines whether lasting locomotor, learning, and memory impairments occur.
Changes in Lumbar Disk Morphology Associated With Prolonged Sitting Assessed by Magnetic Resonance Imaging
Authors: Billy Gregory G. , Lemieux Susan K. , Chow Mosuk X.
Published: March 2014

Objective

To determine what if any changes occur to the lumbar disks in the spine after prolonged sitting with and without intermittent breaks during a 4‐hour period.

Design

A prospective observational study.

Setting

An academic outpatient clinic.

Methods

The measurement of lumbar disk changes was performed with 12 subjects after an analysis of a mid sagittal lumbar magnetic resonance image, which measured lumbar disk height and disk diameter. Scanning and analysis were done over a 2‐day period: day 1 at the start of the work day and 4 hours later after continuous sitting; at the start of work day 2 and after four hours after a change in position and stretching protocol every 15 minutes.

Results

For this study, we first evaluated each level of the lumbar spine for any changes after prolonged sitting for 4 hours over the 2 days. Multiple comparisons bias was eliminated by a Bonferroni correction to limit the overall experiment‐wise error rate to .05. The comparison was conducted by using a paired t‐test when the normality condition was satisfied and by using a Wilcoxon signed rank test when normality was not satisfied. To test for normality, a Shapiro‐Wilk test was used. We found that, for disk height, L4‐5 was significantly decreased at the end of the sitting for day 1 but not for day 2. There were no significant height changes for the other lumbar disks. In addition, for disk diameter, there were no significant differences present for any of the disks.

Conclusions

Analysis of the data shows that the greatest change in disk height is at the L4‐5 level after prolonged sitting without intermittent breaks. The other levels did not show a significant change in their height. The findings also showed that the L4‐5 height changes were not significant with brief positional changes every 15 minutes. Fewer changes in disk height may correlate with an improvement in low back pain and disability.
Disaster Management Among Dental Graduates in a Private Dental Institution in India: A Pilot Study
Authors: Chhabra Kumar Gaurav , Rajesh Guru Raghavendran , Shetty Preetha J. , Prasad Kakarla V V , Chhabra Chaya , Muddapur Mahadevayya
Published: March 2014

Objective

To obtain insights into disaster management among dental graduates in a dental institute in India.

Methods

A total of 103 of 104 house surgeons in Shri Dharmasthala Manjunatheswar College of Dental Sciences and Hospital, Dharwad, participated in the main study (response rate = 99.04%). Their knowledge, attitude, and behavior regarding disaster management were assessed by use of a survey questionnaire. Information was also collected regarding age, gender, religion, and residence.

Results

Mean knowledge, attitude, and behavior scores toward disaster management were 45.46%, 79.53%, and 37.70%, respectively. A significant relationship was observed between knowledge and attitude scores (r= 0.248,P= .012). No significant differences were found in knowledge, attitude, and behavior by gender, religion, and residence. Religion was a significant predictor of knowledge scores (χ2= 10.108,P= .006).

Conclusions

Respondents had favorable attitudes toward disaster management, but their knowledge and behavior required considerable improvement. Knowledge of the respondents was significantly associated with their attitude. This pilot study highlights the need for curriculum changes in dental education in India and further nationwide study. (Disaster Med Public Health Preparedness. 2014;0:1-7)
Algorithms for collision-free navigation of mobile robots in complex cluttered environments: a survey
Authors: Hoy Michael , Matveev Alexey S. , Savkin Andrey V.
Published: March 2014

We review a range of techniques related to navigation of unmanned vehicles through unknown environments with obstacles, especially those that rigorously ensure collision avoidance (given certain assumptions about the system). This topic continues to be an active area of research, and we highlight some directions in which available approaches may be improved. The paper discusses models of the sensors and vehicle kinematics, assumptions about the environment, and performance criteria. Methods applicable to stationary obstacles, moving obstacles and multiple vehicles scenarios are all reviewed. In preference to global approaches based on full knowledge of the environment, particular attention is given to reactive methods based on local sensory data, with a special focus on recently proposed navigation laws based on model predictive and sliding mode control.
Mathematical tidal model of the Tay Estuary
Authors: Williams D. J. A. , Nassehi V.
Published: March 2014

Synopsis

A one-dimensional mathematical model based on an implicit finite difference scheme is used to predict tidal levels and discharges throughout the Tay Estuary. The model accounts for the transformation of the tidal level curve along the estuary and predicts a maximum tidal range near Flisk. There is a measure of agreement between computed velocities and observed data in the upper reaches of the estuary.
The bracken problem in the Highlands and Islands
Authors: MacLeod A.
Published: March 2014

Synopsis

The only serious attempt to quantify the area of bracken in Scotland took place in 1957. At that time the Department of Agriculture for Scotland, through the medium of the June Agricultural Census, asked farmers to assess the area of bracken on each holding.

The survey produced a figure of 187,500 ha of bracken-infested land throughout Scotland, of which some 50% was found in the Central, North and West Highland counties of Perth, Inverness and Argyll. One quarter (46,875 ha) of the Scottish total was located on the mainland and islands of Argyll.

Distribution is governed to a great extent by the soil type, exposure and rainfall, with the free-draining slopes of brown soil on the lower hill faces and glen sides providing the ideal habitat for the plant. The poorly drained acid peat as found over much of the Highland areas is an unsuitable medium for bracken growth but thin peat overlying mineral soil may be subject to bracken encroachment.

The crux of the problem lies in the imbalance of brown soils to peat land.

The limited areas of the mineral soils, which are located on the accessible lower slopes, have a marked potential for improved grazing and, by virtue of better drainage, are capable of more complete utilisation in an intensive stocking system.

Bracken control and subsequent grass sward establishment can form the key to greatly increased levels of productivity. This is illustrated by detailed reference to one farm in Argyll where over the past five years an attempt has been made to operate the Hill Farming Research Organization (H.F.R.O.) concept of a Two Pasture System.
Cytology ofBetula albaL. complex
Authors: Brown I. R. , Williams D. A.
Published: March 2014

Synopsis

The morphological variation between and within species ofBetulahas resulted in taxonomic confusion which chromosome studies have been aimed at reducing. The paper briefly reviews the general situation and summarizes recent work at Aberdeen.

Betulaforms a polyploid series with chromosome numbers ranging from 2n = 28 to 2n = 84. The native British arborescent birchesB. pendulaandB. pubescensEhrh. have respectively 2n = 28 and 2n = 56 chromosomes. Meiosis is essentially regular but many phenomena occur which may account for the production of gametes with non-haploid chromosome numbers. Variation in somatic chromosome number within the leaf tissues of both species is common and trees have been identified whose modal chromosome counts lie between 28 and 56. Some of these trees are of hybrid origin while others may aneuploidB. pubescens. The former types are sterile while the latter cross freely amongst themselves and with 2n = 28 and 2n=56 trees.
Meat production
Authors: Lawrie Ralston
Published: March 2014

Synopsis

Much of the land surface of Scotland is suitable only for grazing ruminants, but, however inefficient in comparison with plants, these represent the sole feasible means of converting sparse vegetation into an organoleptically desirable and highly nutritious commodity.

The efficiency of meat production could be increased by hormonal enhancement of fertility and growth in cattle and sheep and by various advances in meat science whereby abattoir operations could be greatly accelerated. The latter could involve electrical killing and muscular stimulation, hot deboning and selective conditioning of portions of the carcase. Modernization of abattoir operations would facilitate the economic recovery and upgrading of underutilized animal protein of intrinsically high biological value.

An increase in the preservation of meat and meat products by low doses of ionizing radiation in combination with chilling and by freezing can be envisaged.

Irrespective of current controversies on diet, the nutritive excellence of meat is utterly factual. There are thus both reasons and opportunities for further development of Scottish meat production by ruminants.
Epilogue: recommendations of the Workshop Session
Authors: McCave I.N.
Published: March 2014

Following the presentation of research papers, a group of invited participants examined the opportunities for further research in the Rockall Channel area. The chairman suggested that fundamental oceanographic problems which were well displayed in the area should be the focus of attention rather than regional studies for their own sake. It is indeed fortunate that a region so close to home ports should show many features whose examination would lead to general advances in oceanography. The area has an important slope current on its east side and influx of Norwegian Sea Overflow along the west. These produce differing sedimentary signatures. The downward flux of energy and rapid flux of particles are perhaps responsible for seasonality shown in reproduction of benthos. The continental margin shows significant upwelling and high organic productivity
The SOTEAG programme of monitoring in Sullom Voe
Authors: Foxton P.
Published: March 2014

Synopsis

The Shetland Oil Terminal Environmental Advisory Group (SOTEAG) has initiated a programme of environmental monitoring in Sullom Voe, which is funded by the Sullom Voe Association Ltd (S.V.A.Ltd). Its aim is to provide a continuing check on the effectiveness of the regulatory measures in operation at the terminal by providing early warning of harmful environmental effects due to the anticipated low-level, continuous discharge of predominantly oily water effluents and occasional accidental spills. In designing a programme the limitations of available methods for monitoring the biota so as to detect the effects of chronic pollution have been recognised. The programme adopts an integrated approach based on regular quantitative surveys of selected key marine habitats or biota, including rocky shore, soft shore, salt marsh and benthos associated with a programme to monitor levels of hydrocarbons and heavy metals in sediments and the tissues of selected target organisms. The network of sites and sampling stations has been planned to measure gradients of effect over a wide area having the terminal as its focus and primary source of effluent. The programme also includes projects to monitor atmospheric pollution (SO2) and ornithological monitoring. A flexible approach has been adopted and the programme will be modified in the light of experience and circumstances. Results are reported on annually to SOTEAG's Monitoring Committee which oversees the programme and interprets the results for submission to SOTEAG and then to S.V.A. Ltd.
The benthic ecology of Sullom Voe
Authors: Pearson T. H. , Eleftheriou A.
Published: March 2014

Synopsis

The topographic and sedimentary characteristics of the Voe are briefly described and used to define the distribution of epifaunal and macro- and meio-infaunal communities throughout the Voe. The structural complexity of the communities, their interdependence on one or a group of dominant species, and their trophic relationships are emphasized. Changing distributions with depth and in time are examined in detail, particularly in relation to the intermittently eutrophic conditions occurring in the inner basin of the Voe.
Asymmetric cell division and differentiation; fern spore germination as a model. II. Ultrastructural studies
Authors: Bassel Alix R.
Published: March 2014

Synopsis

The germination of Onoclea spores is a model system with many advantages for the study of asymmetric cell division and cellular differentiation. Our results suggest that both microtubules and a lipophilic site are important in the nuclear migration to one end of the spore prior to asymmetric cell division. A metalbinding region containing pore-like structures in the proximal face of the spore coat may be a source of the inherent polarity of the spore. The pattern of endogenous metal binding during germination has been characterised using a sulphide-silver stain. Metal-binding sites are described in a differentiating system in which polarity is imposed externally using polarised red light. The possibility of a role of ion gradients in determining the direction of nuclear migration is discussed.
Observations on the ecology of hybridisation in the clubmosses (Lycopodiaceae)
Authors: Øllgaard Benjamin
Published: March 2014

Synopsis

Ecological conditions for intergametophytic mating and interspecific hybridisation in the clubmosses are discussed. Several features, including the number of recorded hybrids, records of gametophyte population densities, and conditions for movement of the male gamete in the soil, indicate that intergametophytic mating in Lycopodium is not especially impeded by the subterranean habitat, as has been commonly assumed. The evidence from one site indicates highly effective spore dispersal, and a greater ecological tolerance than expected for the species involved. Two cases are discussed in which hybrids have been formed between ecologically and/or taxonomically very different parent species, in the absence of one parent sporophyte, or with one of the parent species sporophyte poorly adapted to the hybrid habitat. The protected, relatively uniform, subterranean gametophyte habitat is thought to account for successful gametophyte growth and hybridisation between species of widely different sporophyte ecology.
The surface fauna of Xenopus skin
Authors: Tinsley R. C. , Whitear M.
Published: March 2014

Synopsis

Regular moulting can prevent colonisation of the skin surface by epibionts, although some invading organisms are sufficiently mobile to overcome this protective device. Bacteria and sessile protozoans settle on the surface of the claws of Xenopus, where the keratinised cells are not shed as regularly as on the skin. Alternatively, parasites may inhabit the orifices, which also are not affected by moulting.