bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of forest floor coverage on overland flow and soil erosion on hillslopes in Japanese cypress plantation forests
Authors: Miyata Shusuke , Kosugi Ken'ichirou , Gomi Takashi , Mizuyama Takahisa
Published: June 2009

We examined the effects of forest floor coverage on overland flow generation and soil erosion in mature Japanese cypress plantations with different coverage conditions: sparse understory and litter (uncovered plots), dense fern understory and litter (covered plots), and experimental removal of vegetative floor coverage on the covered plots (removal plots). We measured soil hydraulic properties and monitored overland flow and soil erosion in three replicated plots (approximately 1 × 2 m each) representing uncovered, covered, and removal conditions. Because of the strong water repellency of the surface soil, a substantial amount of overland flow occurred, even in covered plots. Nevertheless, the annual overland flow in covered plots was 37% of that in uncovered plots. Annual soil erosion in uncovered plots was 3.7 times greater than that in covered plots. Although overland flow in removal plots was similar to that in uncovered plots, soil erosion in the former was significantly greater than in the latter. These results suggest that differences in soil erodibility between the plots were essential determining factors of erosion and were no less important than floor coverage. We quantified the effects of floor coverage and soil erodibility independently and examined the relationship between coverage and erosion by applying an erosion model. In covered plots, floor coverage prevented 95% of soil detachment by raindrops, which was the dominant mechanism in reducing soil erosion, as compared with it inhibiting overland flow and resisting sediment transport. The soil erodibility of plots with ground cover was 4.5 times higher than that of uncovered plots. This implies that simply comparing plots with different coverage conditions is not sufficient for examining the effects of vegetation coverage on soil erosion.
Are tilt measurements useful in detecting tsunamigenic submarine landslides?
Authors: Brune Sascha , Babeyko Andrey Y. , Sobolev Stephan V.
Published: June 2009

Large submarine landslides can generate dangerous tsunamis. Because of their long‐period signal, detection of landslides by common seismological methods is difficult. Here we suggest a method of detecting submarine landslides by using an array of land‐based tiltmeters. The displacement of a large volume of sediments during landsliding produces a detectable elastic response of the lithosphere. We propose a technique to calculate this response and to invert for tsunami relevant parameters like slide location, volume, and velocity. We exemplify our method by applying it to the Storegga slide west of Norway and other tsunamigenic landslide events. The parameter which can be most robustly estimated from tiltmeter array measurements is the product of slide volume and its velocity (slide tsunamigenic potential). This parameter also controls the amplitude of the generated tsunami wave. The inversion accuracy of this parameter and the estimated tsunami height near the coast depends on the noise level of tiltmeter measurements, distance of the tiltmeters from the slide, and slide tsunamigenic potential itself. The tsunamigenic potential of the most dangerous slides like Storegga can be estimated well by tiltmeters at the coast if the effective noise level does not exceed 50 nrad.
Distribution of 127I and 129I in precipitation at high European latitudes
Authors: Aldahan A. , Persson S. , Possnert G. , Hou X. L.
Published: June 2009

We here present the most extensive data set on the distribution of 127I and 129I in precipitation (rain and snow) covering the period 2000–2006 and European latitudes 55°N–68°N. Our results indicate a wide variation in the concentrations and fluxes of the two isotopes associated with generally higher values at near coastal sites compared to the inland ones. Total wet‐related annual deposition of 127I and 129I on Sweden and Denmark is estimated at about 1.2 × 109 g and 60 g respectively. The average annual 129I wet deposition accounts for <1% and <0.05% of the total annual gaseous and liquid, respectively, discharges from the Sellafiled and La Hague Facilities. The 127I annual wet deposition represents <1% of the estimated global oceanic iodine flux. Air mass trajectories suggest that events of enhanced 129I in precipitation are closely related to southwesterly weather fronts from regions of elevated concentrations.
Coseismic surface‐ruptures and crustal deformations of the 2008 Wenchuan earthquake Mw7.9, China
Authors: Hao Ken Xiansheng , Si Hongjun , Fujiwara Hiroyuki , Ozawa Taku
Published: June 2009

The irregularly distributed surface fault‐ruptures of the Wenchuan earthquake spanned over 200 km along the Longmen Shan(LMS) fault zone. Through field investigations, we found over 10 coseismic surface‐ruptures, with maximum vertical displacements of approximately 6 m on the Yingxiu‐Beichuan fault and 2 m on the Guanxian‐Anxian fault; however, the entire fault rupture movement was still not clearly understood since high topographic areas were inaccessible. Thus, we used interferometric synthetic aperture radar (InSAR) satellite observations to capture whole coseismic surface‐ruptures and crustal deformations across the LMS faults. We created a novel bi‐fault‐slip model to invert fault‐slips using InSAR information which yielded that thrust fault‐slips were dominant at YingXiu, Houshenggou and Bajiaomiao in the near‐epicenter segment, while the dextral fault‐slips were dominant at Pingtong and Nanba along the northeast segment. The combination of field investigations and simulations suggested that the two coseismic fault zones ruptured with an irregular surface distribution accompanied by crustal deformations.
Observed dimming effect during a forest fire in the southeastern United States and the role of aerosols
Authors: Prabha Thara V. , Hoogenboom Gerrit
Published: June 2009

A surface dimming effect during a forest fire was observed in the incoming solar radiation measurements of the Georgia Automated Environmental Monitoring Network (AEMN). A combination of in situ AEMN and Moderate Resolution Imaging Spectroradiometer (MODIS) datasets were used to demonstrate the implications on the forecasts when aerosol radiative effects are not included in the Weather Research and Forecasting (WRF) model. The clear sky incoming radiative flux predicted by the model at the surface was overestimated when aerosol optical depths (AODs) exceeded 0.2, which in turn caused a positive temperature bias and a negative mixing ratio bias at the surface. These biases resulted from differences in the energy partitioning at the surface, where the main contribution was from enhanced sensible heat flux. The model atmosphere was also cooler and drier than the MODIS profiles, indicative of the aerosol induced warming below 6 km.
Rising Zinc: A Significant Cause of Ischemic Neuronal Death in the CA1 Region of Rat Hippocampus
Authors: Stork Christian J , Li Yang V
Published: June 2009

There is a rising intracellular Zn2+ transient during neuronal ischemic hypoxia (oxygen-glucose deprivation and reoxygenation, OGD/R). The results of our recent works suggest that the OGD/R-induced Zn2+ transient can readily be mistaken for a Ca2+ transient. The aim of this study was to examine the respective functions of Zn2+ and Ca2+ in OGD/R-induced neuronal injury. We showed that [Zn2+]i accumulation was consistently met with the induction of OGD/R-induced cell injury. Ca2+ accumulation induced with high [K+] (to open voltage-gated calcium channels) or ionomycin (a Ca2+ ionophore) caused a moderate neuronal injury that was reduced significantly by the application of the Zn2+ chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN). In comparison, Zn2+ accumulation, induced with the Zn2+ ionophore pyrithione, resulted in significantly greater injury. The application of nimodipine and MK801 was shown to attenuate neuronal injury only from a mild (10 mins) OGD insult. Neuronal injury from more severe (30 mins) OGD was not mitigated by the ion channel antagonists, whereas treatment with the Zn2+ chelator TPEN did afford significant protection from cell injury. These results indicate Zn2+-mediated damage to be of greater consequence than Ca2+-mediated damage, and collectively support the suggestion that Zn2+ accumulation may be a more significant causal factor of OGD/R-induced neuronal injury.
Clinical Implications of Cortical Microvasculature in Adult Moyamoya Disease
Authors: Czabanka Marcus , Peña-Tapia Pablo , Schubert Gerrit Alexander , Woitzik Johannes , Horn Peter , Schmiedek Peter , Vajkoczy Peter
Published: June 2009

We analyzed cortical microvascular parameters using intraoperative ICG (Indocyaninegreen)-Videoangiography in 13 patients with Moyamoya disease, and carried out correlative studies by comparing them with clinical parameters obtained by digital subtraction angiography, physical examination, and regional cerebral blood flow studies. Patients with reduced cerebrovascular reserve capacity were characterized by increased microvascular surface area (MVSA). In addition, MVSA correlated positively with arterial microvascular transit time. Asymptomatic patients were characterized by increased arterial microvascular transit time. We show that patients with a higher arteriogenic potential to alter cortical microvasculature are characterized by a more favorable hemodynamic situation and reduced clinical symptoms.
Culture-Induced Changes in Blood—Brain Barrier Transcriptome: Implications for Amino-Acid Transporters in vivo
Authors: Lyck Ruth , Ruderisch Nadine , Moll Anton G , Steiner Oliver , Cohen Clemens D , Engelhardt Britta , Makrides Victoria , Verrey Francois
Published: June 2009

Tight homeostatic control of brain amino acids (AA) depends on transport by solute carrier family proteins expressed by the blood—brain barrier (BBB) microvascular endothelial cells (BMEC). To characterize the mouse BMEC transcriptome and probe culture-induced changes, microarray analyses of platelet endothelial cell adhesion molecule-1-positive (PECAM1+) endothelial cells (ppMBMECs) were compared with primary MBMECs (pMBMEC) cultured in the presence or absence of glial cells and with b.End5 endothelioma cell line. Selected cell marker and AA transporter mRNA levels were further verified by reverse transcription real-time PCR. Regardless of glial coculture, expression of a large subset of genes was strongly altered by a brief culture step. This is consistent with the known dependence of BMECs on in vivo interactions to maintain physiologic functions, for example, tight barrier formation, and their consequent dedifferentiation in culture. Seven ( 4F2hc, Lat1, Taut, Snat3, Snat5, Xpct, and Cat1) of nine AA transporter mRNAs highly expressed in freshly isolated ppMBMECs were strongly downregulated for all cultures and two ( Snat2 and Eaat3) were variably regulated. In contrast, five AA transporter mRNAs with low expression in ppMBMECs, including y+ Lat2, xCT, and Snat1, were upregulated by culture. We hypothesized that the AA transporters highly expressed in ppMBMECs and downregulated in culture have a major in vivo function for BBB transendothelial transport.
Atomic Structures of Molecules Based on Additivity of Atomic and/or Ionic Radii
Authors: Heyrovska Raji , Narayan Sara
Published: June 2009

The authors have shown in recent years that interatomic and interionic distances are sums of the radii of the adjacent atoms and/or ions. Many examples will be provided and it will be shown how the experimental bond lengths agree with the radii sums. The examples include inorganic compounds like alkali halides, metal hydrides, graphene, etc., organic like aliphatic and aromatic compounds and biochemical like nucleic acids, amino acids, caffeine-related compounds and vitamins.
BrainGrab: Capturing Curator Expertise as Reusable Annotation Rules
Authors: Haft Daniel , Basu Malay , Richter Roland
Published: June 2009

Experienced biocurators can outperform automated systems on specific genes once they determine which pieces of evidence should drive annotation, and which annotations should be spread. The annotation logic may weigh both homology evidence (BLAST matches or HMM hits) and non-homology evidence (neighboring genes, metabolic context, taxonomic group). Unfortunately, the expertise developed to annotate each gene is short-lived, and is mostly lost if the logic driving the annotation is not captured. We report the development of BrainGrab, an interface added to the MANATEE manual annotation tool for prokaryotic genomes. The curator can specify evidence scenarios that should always lead to equivalent annotation for similar genes in similar contexts, and thus create new annotation rules while the expertise is fresh. No special knowledge of programming or protein family construction is required. BrainGrab rules can mix and match evidence types from the large array of existing protein family definitions such as Pfam families, sequence analyses such as SignalP, and contextual clues, that is, the same types of evidence already familiar to experienced biocurators. We have now created an infrastructure for collecting, distributing, interpreting, and applying BrainGrab rules for automated annotation. A rules interpreter combines queries of existing evidence with specified new searches to determine if a rule must fire. If so, the interpreter writes a new piece of rule-based evidence. Once deposited, BrainGrab/RuleBase evidence can provide automated annotation, pathway reconstruction, and even input data for other rules. We demonstrate the system with sets of rules for annotating proteins and pathways of siderophore biosynthesis in human pathogens, for annotating common fusion proteins, and for applying the proper nomenclature to bacterial ribosomal proteins. The chance to harness curatorial expertise for building rules creates a promising avenue for community contributions to improved annotation pipelines.
Laryngologist Leon Zamenhof—Brother of Dr. Esperanto
Authors: Wincewicz Andrzej , Sulkowska Mariola , Musiatowicz Marcin , Sulkowski Stanislaw
Published: June 2009

Purpose

To reconstruct the biography of the Polish otorhinolaryngologist Leon Zamenhof (1875–1934), a brother of Ludwik Zamenhof, who is famous for invention of the international language Esperanto.

Method

Biographical information was collected from pre-World War II resources.

Results

Zamenhof developed several important new forms of treatment to help the hearing impaired. Zamenhof was especially interested in the education of deaf children and the therapy necessary to facilitate their integration into society. His significant achievements were a phonetic method of therapy for the hearing impaired and an automatic device for ear insufflation that was considered indispensable in the management of pyorrhea. In addition, Zamenhof initiated various forms of social support among physicians within the medical community of Warsaw, Poland; made health care available to children with hearing impairments; and organized a Jewish school for deaf children. Zamenhof tried to change public attitudes toward deafness, working to promote the integration of the deaf into wider society. He also translated Polish literature into Esperanto.

Conclusions

With similar aims to his brother Ludwik, Leon Zamenhof strived to enhance and broaden communication among people who could not hear and to persuade people to change their attitudes about deafness.
A Selective Annotated Bibliography for Clinical Audiology (1988–2008): Reference Works
Authors: Ferrer-Vinent Susan T. , Ferrer-Vinent Ignacio J.
Published: June 2009

Purpose

This is the 1st in a series of 3 planned companion articles that present a selected, annotated, and indexed bibliography of clinical audiology publications from 1988 to 2008.

Method

Research and preparation of the bibliography were based on published guidelines, professional audiology experience, and professional librarian experience.

Results

This article presents reference works (dictionaries, encyclopedias, handbooks, and manuals). The future planned articles will cover other monographs, periodicals, and online resources.

Conclusions

Audiologists and librarians can use these lists as a guide when seeking clinical audiology literature.
Head Shake Computerized Dynamic Posturography in Peripheral Vestibular Lesions
Authors: Mishra Anupam , Davis Sherrie , Speers Rosemary , Shepard Neil T.
Published: June 2009

Purpose

To determine the sensitivity of a head shake modification to the Sensory Organization Test (SOT) of dynamic posturography in identifying (a) those patients with unilateral, peripheral vestibular hypofunction as indicated by caloric irrigation findings and (b) those patients who report that head movements provoke disruption in postural control.

Method

A prospective, single-blinded, random selection methodology was used with 91 patients stratified by the presence or absence of a significant caloric asymmetry and by the presence or absence of head movement provoked symptoms (independent variables). Postural control performance, as measured by EquiTest during the standard test and a head shake modification, served as the dependent variables.

Results

Receiver operating characteristic curves demonstrated only minor improvement in sensitivity (a) with the head shake modification for unilateral peripheral asymmetry and (b) for identification of those with complaints of head movement provoked imbalance.

Conclusions

The head shake modification to standard SOT increased the test sensitivity to identification of patients with unilateral, peripheral vestibular hypofunction and those with head movement provoked symptoms. However, this occurred with low specificity, resulting in no significant improvement in overall performance with this head shake protocol. Suggestions for further research to improve the performance of the head shake modification of SOT for clinical application are discussed.
Analysis of Distortion Product Otoacoustic Emission Spectra in Normal-Hearing Adults
Authors: Bhagat Shaum
Published: June 2009

Purpose

To evaluate the ability of distortion product otoacoustic emission (DPOAE) spectral characteristics to distinguish between ears with variable hearing sensitivity within the normal range.

Method

Distortion product grams (DP-grams) were acquired with primary tones decremented in 1/8-octave steps and primary-tone levels presented at 65 dB SPL (L1) and 45 dB SPL (L2) across an f2 frequency range of 842–7996 Hz from 22 normal-hearing adults (44 ears). Hearing thresholds of ears classified in Group A (
n
= 22) were better than ears classified in Group B (
n
= 22). Examined parameters of the DP-grams included spectral peak occurrence, peak height, peak width, and DPOAE levels. Analyses of variance were conducted to determine whether DP-gram parameters differed between Group A and Group B.

Results

For the low-resolution DP-grams examined in this study, no significant between-group differences in peak occurrence, peak height, and peak width were observed. DPOAE levels were significantly higher in ears classified in Group A compared with ears classified in Group B in individuals with symmetrical hearing.

Conclusions

Although spectral peaks are evident in DP-grams acquired with low resolution of the primary tones, DPOAE levels are more effective in distinguishing ears with greater hearing sensitivity from less sensitive ears.
Hearing Aid Outcomes for Listeners With High-Frequency Hearing Loss
Authors: Roup Christina M. , Noe Colleen M.
Published: June 2009

Purpose

To determine whether listeners with primarily high-frequency sensorineural hearing loss (HF SNHL) perceived benefit from amplification provided by completely-in-the-canal (CIC) hearing aids.

Method

The Hearing Handicap for the Elderly—Screening version, the Abbreviated Profile of Hearing Aid Benefit, and the Satisfaction With Amplification in Daily Life questionnaires were mailed to 2 groups of listeners (n= 79) who matched preset criteria, including threshold at 2000 Hz and use of CIC amplification. Sixty-seven percent (n= 53) of the questionnaires were returned and were divided into 2 groups. Group I (n= 26) consisted of listeners with normal hearing through 2000 Hz, and Group II (n= 27) consisted of listeners with normal hearing only through 1000 Hz.

Results

Results revealed that both groups perceived significant hearing handicap, hearing aid benefit, and hearing aid satisfaction. Differences between the 2 groups on the 3 measures, however, were not statistically significant.

Conclusions

Listeners with HF SNHL perceived benefit and satisfaction from amplification with CIC hearing aids. Individuals with SNHL limited to the high frequencies should be considered candidates for amplification.
Melting and thermodynamic properties of rare gas nanocrystals
Authors: Karasevskii A. I. , Lubashenko V. V.
Published: June 2009

A self-consistent statistical method [Phys. Rev. B 66, 054302 (2002)] is used to describe the thermodynamic properties of free rare gas nanocrystals, using thin plates as examples. It is shown that the influence of size on the thermodynamic properties of nanocrystals is due to size-dependent quantization of the vibration spectrum affecting the parameters of a statistical distribution function of atomic displacements and, thus, governing the size dependence of the average values of energetic contributions to the Gibbs free energy of the system. For Xe nanocrystals, we present calculated size dependences of the Debye temperature, heat capacity, interatomic distance, melting temperature, etc.
On the problem of observation of two-level tunneling states in supercooled liquids, glass-forming polymers, orientational glasses, and metallic glasses via configurational entropy
Authors: Kokshenev V. B.
Published: June 2009

From general perspectives, there is no conceptual gap between the structural and orientational glasses. Both kinds of glasses expose universal features during primary relaxation [Low Temp. Phys. 33, 617 (2007)]. However, in spite of much effort made to observe generic two-level systems (TLS) in polymers, organic liquids, and plastic crystals via thermodynamic measurements, no similarity unifying glass formers has been established. Re-analyzing a number of experimental studies, it is revealed that no renormalization conditions imposed on occupation numbers of structural units, relaxing to the glass state, were taken into consideration by the experimentalists. In this study, the effective-cluster approach is applied to configurational (excess liquid-over-solid) entropy measured in both supercooled liquids and crystals through the heat capacity. As the result, new relationships between the observable thermodynamic and dynamic characteristics are found for molecular liquids, polymers, and networks on the basis of data available in the literature. Thereby, new constraints of structure relaxation are shown to give strong evidence for the existence of TLS-type embryos of glassy structure in all studied glass formers.
Heat transfer in solid methyl alcohol
Authors: Korolyuk O. A. , Krivchikov A. I. , Sharapova I. V. , Romantsova O. O.
Published: June 2009

The thermal conductivity coefficient κ(T) is measured under equilibrium vapor pressure for two crystalline phases of pure methanol (orientationally ordered and orientationally disordered) at temperatures from 2K to the melting temperature Tm and also for a CH3OH+6.6% H2O glass from 2K to the glass transition temperature Tg and in the supercooled liquid from Tg to 120K. The dependence κ(T) is described approximately as a sum of two contributions: κI(T), describing heat transport by acoustic phonons, and κII(T)—by localized high-frequency excitations. The temperature dependences of the thermal conductivity of primary monoatomic alcohols CH3OH, C2H5OH, and C3H7OH in the glass state are compared. Different mechanisms of phonon scattering in the crystalline phases and glass are analyzed. The κII(T) contribution is calculated within the Cahill–Pohl model. There is an anomaly of the thermal conductivity of the glass state near Tg (a smeared minimum on the κ(T) curve).
Atomic bubbles in impurity-stabilized solid He4
Authors: Lebedev V. , Moroshkin P. , Weis A.
Published: June 2009

The optical absorption and fluorescence spectra of alkali atoms isolated in liquid and solid He matrices depend on specific macroscopic matrix properties, such as their molar volume and (anisotropic) elasticity constants, and provide thus information about the quantum matrix. We apply optical spectroscopy to investigate the properties of a recently discovered impurity-stabilized doped He4 solid that exists in equilibrium with pressurized superfluid helium close to the solidification∕melting point of pure helium. The difference between the local He density around the implanted atoms obtained in the present experiment and the average density measured earlier suggests that the impurity-stabilized solid He is in fact a porous structure filled with liquid helium.
The thermal conductivity jump at crystal-liquid phase transition in CHCl3, C6H6, and CCl4: the action of rotational molecular motion
Authors: Pursky I. O. , Konstantinov V. A. , Bulakh V. V.
Published: June 2009

The thermal conductivity of liquid CHCl3, C6H6, and CCl4 is measured by a steady-state method under saturated vapor pressure in the temperature regions corresponding to pre-crystallization temperatures. The experimental results obtained are used to investigate the isobaric thermal conductivity jump ΔΛp at the crystal-liquid phase transition in CHCl3, C6H6, and CCl4. The contributions of the phonon-phonon and phonon-rotational interaction to the total thermal resistance in solid and liquid state are specified using a modified method of reduced coordinates. The decrease in the thermal conductivity at the crystal-liquid phase transition, ΔΛp, is explained by a combined effect of variations in positional distribution of molecules and in the form of rotational molecular motion.
Zero-phonon emission bands of solid hydrogen at 6–12μm wavelength. An astrophysical phenomenon
Authors: Schaefer J.
Published: June 2009

Infrared emission bands in the wavelength range of 6–12μm observed in the ISO-SWS mission are assigned to rotational zero-phonon bands of solid parahydrogen by using Van Kranendonk’s approximate rigid-lattice method. This method is based on superposed electric quadrupole pair interactions and superposed quadrupole induced dipole moments of pairs in the hcp crystal. Accordingly, the approximate formalism uses zero-order H2 pair wave functions. Symmetry effects of the hcp crystal require preference of rotational pair transitions. The interaction potential of the pairs is confined to the electric quadrupole-quadrupole interaction. Zero-phonon emission bands of H2 pair transitions fitted to the spectrum contain at least one delocalized j=2 state initially and/or finally because of their significantly enhanced emission rates. They also yield the characteristic bandwidths which fit nicely to the widths of the observed features. The frequency positions of the seven pure parahydrogen pair transitions used, obtained from experimentally determined rotational solid hydrogen energy levels, are in perfect agreement with the observed features, whereas the three mixed ortho-parapair transitions need a presently unknown frequency correction, caused by the migration of the ortho-H2 molecules into the parahydrogen crystal prior to emission, the so-called initial excess binding energies. The astrophysical setup of the observed source is discussed in the end of the paper.
Pathways to metallic hydrogen
Authors: Silvera I. F. , Deemyad S.
Published: June 2009

The traditional pathway that researchers have used in the goal of producing atomic metallic hydrogen is to compress samples with megabar pressures at low temperature. A number of phases have been observed in solid hydrogen and its isotopes, but all are in the insulating phase. The results of experiment and theory for this pathway are reviewed. In recent years a new pathway has become the focus of this challenge of producing metallic hydrogen, namely a path along the melting line. It has been predicted that the hydrogen melt line will have a peak and with increasing pressure the melt line may descend to zero Kelvin so that high pressure metallic hydrogen may be a quantum liquid. Even at lower pressures hydrogen may melt from a molecular solid to an atomic liquid. Earlier attempts to observe the peak in the melting line were thwarted by diffusion of hydrogen into the pressure cell components and other problems. In the second part of this paper we present a detailed description of our recent successful demonstration of a peak in the melting line of hydrogen.
Metal pumps liquid uphill
Authors: Vorobyev A. Y. , Guo Chunlei
Published: June 2009

The behavior of liquids on a solid surface is determined by the surface wettability. In this work, by structuring metal surfaces with high-intensity femtosecond laser pulses, we engineer a unique surface pattern that dramatically modifies surface wetting properties. In a gravity-defying way, the treated metal surfaces make liquids sprint vertically uphill at an unprecedented speed of 1 cm/s. Furthermore, the surface structures we create here rapidly transport a significant amount of liquid against gravitation to an elevated point above the reservoir level, thus bringing this effect to potential real-life applications.
Amorphous polymeric nitrogen—toward an equation of state
Authors: Yakub L.
Published: June 2009

The thermodynamic properties of amorphous polymeric nytrogen are analyzed theoretically on the basis of a free-energy expansion. An approach allowing estimation of the Helmholtz free energy of the high-pressure disordered condensed phases of nitrogen is proposed. The approach is based on expansion of the excess entropy in interatomic correlations and is tested on existing Monte Carlo simulation data. Some specific problems arising on this path and their possible solutions are discussed.
Structure of nitrous oxide-carbon dioxide alloys
Authors: Solodovnik A. A.
Published: June 2009

The structure of N2O–CO2 solid mixtures is investigated by transmission electron diffraction over the entire range of their mutual concentrations. In the temperature range 5–65K the experimental data indicate no phase separation in these alloys. The average structure of the solutions belongs to the Pa3 symmetry. The behavior of the concentration dependence of the lattice parameter has a nonmonotonic character, displaying a sharp step, the positions of which on the concentration scale depend on the deposition temperature. A possible explanation of this phenomenon is suggested.
The influence of the disordered dipole subsystem on the thermal conductivity of solid CO at low temperatures
Authors: Sumarokov V. , Jeżowski A. , Stachowiak P.
Published: June 2009

The thermal conductivity of solid CO is investigated in the temperature range 1–20K. The experimental temperature dependence of thermal conductivity of solid CO is described using the time-relaxation method within the Debye model. The comparison of the experimental temperature dependences of the thermal conductivity of N2 and CO shows that in the case of CO there is an additional large phonon scattering at temperatures near the maximum. Analysis of the experimental data indicates that this scattering is caused by the frozen disordered dipole subsystem, similar to a dipole glass. The scattering is described by resonant phonon scattering on tunneling states and on low-energy quasi-harmonic oscillations within the soft potential model.
Complex modular structure of large-scale brain networks
Authors: Valencia M. , Pastor M. A. , Fernández-Seara M. A. , Artieda J. , Martinerie J. , Chavez M.
Published: June 2009

Modular structure is ubiquitous among real-world networks from related proteins to social groups. Here we analyze the modular organization of brain networks at a large scale (voxel level) extracted from functional magnetic resonance imaging signals. By using a random-walk-based method, we unveil the modularity of brain webs and show modules with a spatial distribution that matches anatomical structures with functional significance. The functional role of each node in the network is studied by analyzing its patterns of inter- and intramodular connections. Results suggest that the modular architecture constitutes the structural basis for the coexistence of functional integration of distant and specialized brain areas during normal brain activities at rest.
Temperature-dependent neutron diffraction study of phase separation at morphotropic phase boundary in (1−x)BiScO3–xPbTiO3
Authors: Kim Bongju , Tong P. , Kwon Daeyoung , Park J. M. S. , Kim Bog G.
Published: June 2009

We report the results of temperature-dependent neutron powder diffraction experiments on (1−x)BiScO3–xPbTiO3 (x=0.62, 0.64, and 0.66) within the morphotropic phase boundary. In all samples the monoclinic phase is found to coexist with the tetragonal phase below the ferroelectric transition temperature. The details of structural information demonstrate a delicate balance between the coexisting two phases for x=0.64. Such delicate balance is suggested to be sensitive to an external electric field, thus responsible for the enhanced electromechanical properties observed for x=0.64. Our result reveals that phase separation and the delicate balance between two phases are crucial to understand the unique properties at the morphotropic phase boundary in (1−x)BiScO3–xPbTiO3 ferroelectric systems.
Impact of floating dot distribution on memory characteristics of self-aligned dots-on-nanowire memory
Authors: Nakajima Anri , Fujiaki Tomo , Ezaki Tatsuya
Published: June 2009

A nanowire memory device with self-aligned Si nanoscale floating dots has been fabricated to overcome the tradeoff between retention time and programming speed. The dependence of memory characteristics on the dot number and distribution have been systematically analyzed experimentally and numerically to provide design guidelines for optimizing device performance. Distributing multiple floating dots in series along the channel with each dot covering the whole channel width is essential for better retention characteristics, while maintaining similar programming characteristics without increasing the operating voltage. The spacing between dots is also an important factor for optimizing device performance. Taking into account the compatibility of the fabrication process with that of the conventional flash-type nonvolatile memory, the self-aligned dots-on-nanowire memory with multiple floating dots distributed in series along a nanowire channel is the best structure for high-performance memory.
Second sound waves in orthodeuterium, parahydrogen quantum crystals and neon crystals
Authors: Khodusov V. D. , Blinkina A. A.
Published: June 2009

The possibility of second sound wave propagation in isotopic pure ideal single crystals of orthodeuterium, parahydrogen, and neon is studied. The same collision frequencies as those used in Callaway’s model to describe experimental data on thermal conductivity are used to find the region of existence of second-sound waves, which lies in the region of the maximum value of the thermal conductivity. The concentrations of the isotopes H1, D2, and Ne22 below which weakly damped second sound waves can exist are determined. It is important to take account of phonon scattering by the boundaries of the sample.
Nonlinear Wigner solid transport over superfluid helium under ac conditions
Authors: Monarkha Y. P. , Kono K.
Published: June 2009

Nonlinear transport properties of the two-dimensional Wigner solid of surface electrons on superfluid helium are studied for alternating current conditions. For time-averaged quantities like Fourier coefficients, the field–velocity characteristics are shown to be qualitatively different from those found in the dc theory. For a spatially uniform current a general solution for the field–velocity relationship is found which turns out to be strongly dependent on the current frequency. If the current frequency is much lower than the ripplon damping parameter, the Bragg–Cherenkov resonances which appear at high enough drift velocities acquire a distinctive saw-tooth shape with long right-side tails independent of small damping. For current frequencies which are close to or higher than the ripplon damping coefficient, the interference of ripplons excited at different time intervals results in a new oscillatory (in drift velocity) regime of Bragg–Cherenkov scattering.
Efficiency enhancement in seeded and self-amplified spontaneous emission free-electron lasers by means of a tapered wiggler
Authors: Freund H. P. , Miner W. H.
Published: June 2009

The enhancement of the efficiency in free-electron lasers (FELs) through the use of a tapered wiggler is well known. The physics of the tapered wiggler interaction has been studied in theory and simulation, and large efficiency enhancements have been observed in the laboratory in oscillators and seeded amplifiers. In this paper, we study the differences in the tapered wiggler interaction between seeded amplifiers and in FELs that start up from noise and grow to saturation in a single pass through the wiggler. This configuration is commonly referred to as self-amplified spontaneous emission (SASE). In comparison with seeded amplifiers, SASE FELs exhibit shot-to-shot fluctuations due to random phase noise in the electron bunches, and our purpose in this paper is to determine the effect of this phase noise on the tapered wiggler interaction. To this end, we study the interaction numerically using the MEDUSA simulation code for seeded and SASE FELs operating in the infrared regime. The results of the simulations indicate that the overall efficiencies of the seeded and SASE FELs are comparable for a uniform wiggler but that the output spectrum for the SASE FEL is much broader than for the seeded case. For a tapered wiggler, the efficiency enhancement in the SASE FEL is less than that found in the seeded example due to the broader excited spectrum that detunes the tapered wiggler interaction.
Analytical description of the metal-assisted growth of III–V nanowires: Axial and radial growths
Authors: Plante Martin C. , LaPierre Ray R.
Published: June 2009

The growth of III–V nanowires from metal seed particles is described in an analytical manner within the framework of a material conservation model. Direct impingement of growth species on the particle, coupled to their diffusion from the sidewall and the substrate surface, are considered in the derivation of expressions for the time evolution of both axial and radial growths. Two regimes are distinguished: the structure originally grows in a purely axial manner until its length exceeds the diffusion length of adatoms incoming from the substrate, at which point sidewall nucleation is triggered, resulting in a shell expanding radially in the lower part of the wire. Factors that take into account the nonunity probability of inclusion of group III adatoms in the axially growing crystal are introduced. Moreover, a step-mediated growth is included to describe the axial evolution of the shell. The numerical values of the various parameters were assessed by fitting the model to experimental data on the morphology evolution of molecular-beam-epitaxy-grown GaAs and InAs nanowires.
Effect of the transport current on microwave absorption by vortices in type-II superconductors
Authors: Shklovskiĭ V. A. , Bik Khop Dang Tkhi
Published: June 2009

The results of theoretical calculations of the current-voltage characteristics, absorbed power, and impedance of type-II superconductors in the anisotropic pinning model are presented.
Oscillations of an electron–hole pair condensate in excitonic traps
Authors: Bezuglyĭ A. I. , Shevchenko S. I.
Published: June 2009

A superfluid state can arise in bilayer systems as a result of pairing of spatially separated electrons and holes. In the limit of low electron–hole pair density the superfluid state can be described by a nonlinear dynamical equation. In the present paper a microscopic derivation of such an equation for the wave function of the electron–hole pair condensate in a strong magnetic field is presented. This equation is generalized to the cases where an electric field is applied to the system and where the composition of the semiconductor forming conducting layers varies in space. The solution of the dynamical equation gives the frequencies of the characteristic oscillations of the electron–hole pair condensate in excitonic traps produced by electric charge or variation of the composition of the semiconductor.
A theory of plasma oscillations in metallic nanoparticles
Authors: Jacak L. , Krasnyĭ Yu. P. , Chepok A. O.
Published: June 2009

Equations describing the behavior of plasma oscillations that can arise on the surface as well as inside metallic spherical nanoparticles are obtained in the random-phase approximation. The frequencies of all characteristic plasma oscillations arising on the surface and in the volume of a particle are determined. It is shown that the volume plasma oscillations can give rise to forced oscillations on the surface of a nanoparticle. The effect of plasma oscillations on the optical properties of a dielectric medium containing metallic nanoparticles is determined.
Relaxation channels and transfer of energy stored by pre-irradiated rare gas solids
Authors: Savchenko E. V. , Khyzhniy I. V. , Uyutnov S. A. , Gumenchuk G. B. , Ponomaryov A. N. , Bondybey V. E.
Published: June 2009

The processes of energy relaxation in rare gas solids pre-irradiated with an electron beam are discussed. The emission of exoelectrons and photons from rare gas solids is studied. Investigations are performed by a set of activation spectroscopy methods applied simultaneously to each sample. Photon-stimulated exoelectron emission from solid Ne is observed for the first time.
Low-temperature relaxation processes in a Cu–Nb nanostructured fiber composite
Authors: Vatazhuk E. N. , Pal-Val P. P. , Pal-Val L. N. , Natsik V. D. , Tikhonovsky M. A. , Kupriyanov A. A.
Published: June 2009

The elastic and dissipative properties of nanostructured superconducting fiber composites Cu–32 vol.% Nb at frequencies of the order of 70kHz are investigated in the temperature range 2–320K. The composites, prepared by the method of intensive plastic deformation, consist of a fragmented copper matrix uniformly filled with niobium fibers having diameters of 200–500nm. It is found that the acoustic properties of the composite are mainly determined by the properties of the copper matrix. Near 90K a relaxation peak of the internal friction is observed, with activational parameters close to those of the Bordoni peak in copper. Below 12K the temperature dependence of the dynamic Young’s modulus is described by the thermally activated relaxation of two-level systems in a highly disordered medium. The influence of high-temperature annealing on the observed effects is investigated.
Enhancement of the superconducting order parameter in the compound Dy0.8Y0.2Rh4B4 at the phase transition of its magnetic subsystem from the antiferromagnetic to the ferrimagnetic state
Authors: Dmitriev V. M. , Zaleski A. , Khlybov E. P. , Rybaltchenko L. F. , Khristenko E. V. , Ishchenko L. A. , Terekhov A. V.
Published: June 2009

The dependence of the superconducting order parameter Δ on magnetic field H in the compound Dy0.8Y0.2Rh4B4 is investigated experimentally for the first time at temperatures both above and below the antiferromagnet-ferrimagnet phase transition in the magnetic subsystem of the compound at TN≈2.7K. It is shown that this phase transition has a substantial influence on the charge subsystem of the superconductor and the parameter Δ. The parameter Δ turns out to be larger in the presence of the uncompensated magnetic moment of the ferrimagnetic state than in its absence in the antiferromagnetic state. In Dy0.8Y0.2Rh4B4 the charge and spin subsystems are substantially coupled, and the mechanism of superconducting pairing may be unconventional.
Electron doping of NbSe2
Authors: Eremenko V. V. , Ibulaev V. V. , Sirenko V. A. , Shvedun M. Yu. , Kulikov L. M. , Petrusenko Yu. T. , Borisenko V. M. , Astakhov A. N. , Barankov D. Yu.
Published: June 2009

The influence of fast-electron irradiation on the properties of the hexagonal modification of niobium diselenide, 2H–NbSe2, is investigated by the methods of x-ray and electron diffractometry. The observed changes in the diffractograms are explained by a redistribution of the electron density under irradiation, viz., an increase of the electron density in the planes with high packing density—the basal and prismatic planes {110}, {210}. The appearance of diffuse scattering of x rays and electrons at high doses of irradiation is attributed to growth of the electron density of the Fermi liquid.
Microcantilever array with embedded metal oxide semiconductor field effect transistor actuators for deflection control, deflection sensing, and high frequency oscillation
Authors: Chou Stanley S. , Kim Yun Young , Srivastava Arvind , Murphy Benjamin , Balogun Oluwaseyi , Tark Soo-Hyun , Shekhawat Gajendra , Dravid Vinayak P.
Published: June 2009

A batch fabricated microcantilever array with embedded metal oxide semiconductor field effect transistor (MOSFET) is demonstrated to behave as an actuator as well as a strain sensor. Actuation is made possible through MOSFET self-heating effect and metal-silicon bimaterial thermal expansion mismatch. Precise cantilever deflection is achieved with gate modulated saturation current. Controllable deflection and oscillation are demonstrated, with amplitude of 212 nm measured through laser interferometry near first resonant frequency. Higher amplitude is attainable through higher bias. Such in situ actuation and sensing promises to have applications ranging from nanolithography to microfluidic mixing, among others, which require precise and controllable nanoscale deflection.
Elastic relaxation in patterned and implanted strained silicon on insulator
Authors: Baudot S. , Andrieu F. , Rieutord F. , Eymery J.
Published: June 2009

Mechanical relaxations of strained silicon on insulator (sSOI) nanostructures are studied for the isolation and implantation processes used in transistor technology. Two model systems are quantitatively analyzed by grazing incidence x-ray diffraction: long etched sSOI lines of different widths and bidimensional (2D) sSi samples implanted by As/Xe ions with the same stripe geometry, the gate stack acting as an implantation mask. For sSOI lines, the strain of the initial 2D layer is conserved along the longer direction, i.e., the transport direction. Along the small direction, a large relaxation is observed especially for the smaller widths. This relaxation is almost complete for thicker samples (70 nm), whereas it is much more limited for thinner ones (10 nm). The tuning by etching/size selection of the sSOI initial biaxial stress into uniaxial stress along the transport direction should represent a great advantage for n-metal oxide semiconductor (n-MOS) devices in terms of mobility. Similar relaxation anisotropies have been observed for the implanted samples with 60 nm thickness. In this case, the relaxed small dimension of the area under the gate stack corresponds to the transport direction. This direct source/drain implantation step should therefore damage the performance of partially depleted sSOI n-MOS devices. However these relaxation phenomena should be advantageously used with new integration schemes.