bluuebunny/crossref_metadata_2025 huggingface dataset:
Wrist Arthroscopy
Authors: RETTIG M. E. , AMADIO P. C.
Published: June 2005

We reviewed retrospectively a series of 128 consecutive patients who had wrist arthroscopy at our institution between January 1988 and July 1991. The aim of the procedure was to establish a diagnosis in 27 patients, to challenge a pre-operative diagnosis in 95 patients and to evaluate joint surfaces in six patients.

For the 27 patients with a previously unknown diagnosis, the diagnostic sensitivity was 67% and the specificity 100%. Arthrotomy or other intervention was avoided in 18. For the 95 patients with an established pre-operative diagnosis, arthrotomy was avoided in 45: in 26 the desired procedure could be done arthroscopically, and in 19 the diagnosis, as improved by arthroscopy, was felt not to require further treatment. Procedures performed arthroscopically included débridement of triangular fibrocartilage and inter-carpal ligament tears; lysis of adhesions, and synovectomy. In six patients, arthroscopy was performed to evaluate joint surfaces after fracture reduction or before ulnar shortening osteotomy. In none of the six was arthrotomy felt necessary after arthroscopy.

Wrist arthroscopy avoided the need for further surgery in 66 (52%) of our patients; arthrotomy was avoided in 69 (54%). In cases with significant carpal instability evident pre-operatively, arthroscopy was unlikely to avoid the need for open treatment.
CHANGING PATTERNS OF SOCIAL VARIATION IN STATURE IN POLAND: EFFECTS OF TRANSITION FROM A COMMAND ECONOMY TO THE FREE-MARKET SYSTEM?
Authors: BIELICKI T. , SZKLARSKA A. , KOZIEŁ S. , ULIJASZEK S. J.
Published: June 2005

The aim of this analysis was to examine the effects on stature in two nationally representative samples of Polish 19-year-old conscripts of maternal and paternal education level, and of degree of urbanization, before and after the economic transition of 1990. Data were from two national surveys of 19-year-old Polish conscripts: 27,236 in 1986 and 28,151 in 2001. In addition to taking height measurements, each subject was asked about the socioeconomic background of their families, including paternal and maternal education, and the name of the locality of residence. The net effect of each of these social factors on stature was determined using four-factor analysis of variance. The secular trend towards increased stature of Polish conscripts has slowed down from a rate 2·1 cm per decade across the period 1965–1986 to 1·5 cm per decade between 1986 and 2001. In both cohorts, mean statures increase with increasing size of locality of residence, paternal education and maternal education. The effect of each of these three social factors on conscript height is highly significant in both cohorts. However, the effect of maternal education has increased substantially while that of size of locality of residence and paternal education diminished between 1986 and 2001. These results imply that the influence of parental education on child growth cannot be due solely to a relationship between education and income, but is also perhaps a reflection of household financial management which benefits child health and growth by better educated parents, regardless of level of income. In addition they suggest that, irrespective of whether there are one or two breadwinners in the family, it is the mother, more so than the father, who is principally responsible for the extent to which such management best favours child health and growth. The asymmetry between the importance of maternal as against paternal education for child growth, clearly seen in the 1986 cohort, became more accentuated in 2001, after the abrupt transition from a command to a free-market economy in the early 1990s.
Island-specific preferences of tourists for environmental features: implications of climate change for tourism-dependent states
Authors: UYARRA MARIA C. , CÔTÉ ISABELLE M. , GILL JENNIFER A. , TINCH ROB R.T. , VINER DAVID , WATKINSON ANDREW R.
Published: June 2005

Climate change may affect important environmental components of holiday destinations, which might have repercussions for tourism-dependent economies. This study documents the importance of environmental attributes in determining the choice and holiday enjoyment of tourists visiting Bonaire and Barbados, two Caribbean islands with markedly different tourism markets and infrastructure. Three hundred and sixteen and 338 participants from Bonaire and Barbados, respectively, completed standardized questionnaires. Warm temperatures, clear waters and low health risks were the most important environmental features determining holiday destination choice. However, tourists in Bonaire thereafter prioritized marine wildlife attributes (i.e. coral and fish diversity and abundance) over other environmental features, whereas tourists in Barbados exhibited stronger preferences for terrestrial features, particularly beach characteristics. The willingness of tourists to revisit these islands was strongly linked to the state of the preferred environmental attributes. More than 80% of tourists in Bonaire and Barbados would be unwilling to return for the same holiday price in the event, respectively, of coral bleaching as a result of elevated sea surface temperatures and reduced beach area as a result of sea level rise. Climate change might have a significant impact on Caribbean tourism economy through alteration of environmental features important to destination selection. Island-specific management strategies, such as focusing resources on the protection of key marine or terrestrial features, may provide a means of reducing the environmental and economic impacts of climate change.
Long-term spatio-temporal dynamics of a hedgerow network landscape in Flanders, Belgium
Authors: DECKERS B. , KERSELAERS E. , GULINCK H. , MUYS B. , HERMY M.
Published: June 2005

Although the importance of hedgerows for sustainable agriculture and conservation of rural biodiversity is increasingly being recognized, obtaining insight into the spatial and temporal dynamics of hedgerow networks remains an important challenge for landscape ecologists, with the key factors driving changes in rural landscape structure especially deserving further attention. The present study analyses the long-term history of a hedgerow network landscape in Flanders, Belgium. A detailed reconstruction of the hedgerow network is made at five points in time, starting at the end of the 18th century until present, for 367 distinct 400 m×400 m samples. Whilst hedgerows were mainly concentrated around historical village centres and within valleys at the end of 18th century, the network expanded progressively during the 19th century. In the 20th century, the hedgerow network degraded strongly, with hedgerow density and connectivity declining and mesh-size heterogeneity and network fragmentation increasing, although the network recovered slightly during the 1990s. Different trajectories of change in hedgerow network structure were observed depending on landscape position, with both topography and village proximity significantly affecting hedgerow network dynamics. The present network structure was mainly governed by land use, with highly developed networks being predominantly associated with pasture. Three main conclusions arise from the results of this study. First, the role of land use and landscape position as basic factors steering hedgerow network dynamics at the landscape scale is demonstrated. Second, the long-term perspective of the study enabled insight into the poorly known expansion phase of hedgerow networks, linked mainly with the development of small-scale labour-intensive agriculture. Finally, the findings confirm the large-scale degradation of linear semi-natural habitats in European agricultural landscapes during most of the 20th century, and indicate that a pro-active rural policy can halt and even reverse this process.
Experimental airborne transmission ofSalmonellaAgona andSalmonellaTyphimurium in weaned pigs
Authors: OLIVEIRA C. J. B. , CARVALHO L. F. O. S. , GARCIA T. B.
Published: June 2005

This study tested the hypothesis of airborne transmission ofSalmonellaAgona (Trial I) andSalmonellaTyphimurium (Trial II) in weaned pigs. The trials were performed using stainless-steel/glass isolation cabinets connected by air ducts to permit an unidirectional airflow from cabinet 1 (two control pigs) to cabinet 3 (two sentinel pigs), passing through cabinet 2 (two inoculated pigs). Air samples, pooled faecal samples from the floor and rectal swabs were collected daily and assessed by culture and PCR. A fumigation chamber and rubber gloves coupled to the cabinets allowed sampling without opening the system. Trials I and II lasted 15 and 19 days respectively. The recovery ofS. Agona andS. Typhimurium and detection of seroconversion in sentinel pigs indicate that airborneSalmonellatransmission in weaned pigs over short distances is possible. Further studies on the role of aerosols in the epidemiology ofSalmonellain intensive pig production should be performed.
Quantum studies of hydrogen bonding in formic acid and water ice surface
Authors: Allouche A.
Published: June 2005

The structure and spectroscopy (electronic and vibrational) of formic acid (HCOOH) dimers and trimers are investigated by means of the hybrid (B3LYP) density-functional theory. Adsorption of single and dimer HCOOH on amorphous water ice surface is modeled using two different water clusters. Particular attention has been given to spectroscopic consequences. Several hypotheses on formic acid film growing on ice and incorporation of a single water molecule in the formic acid film are proposed.
Near-infrared optical-absorption behavior in high-beta nonlinear optical chromophore-polymer guest-host materials. II. Dye spacer length effects in an amorphous polycarbonate copolymer host
Authors: Barto Richard R. , Frank Curtis W. , Bedworth Peter V. , Ermer Susan , Taylor Rebecca E.
Published: June 2005

In the second of a three-part series, spectral absorption behavior of nonlinear optical (NLO) dyes incorporated into amorphous polycarbonate, comprised of a homologous series of dialkyl spacer groups extending from the midsection of the dye molecule, is characterized by UV-Vis and photothermal deflection spectroscopy. The dyes are structural analogs of the NLO dye FTC [2-(3-cyano-4-{2-[5-(2-{4-[ethyl-(2-methoxyethyl)amino]phenyl}vinyl)-3,4-diethylthiophen-2-yl]vinyl}-5,5-dimethyl-5H-furan-2-ylidene)malononitrile]. Previous Monte Carlo calculations [B. H. Robinson and L. R. Dalton, J. Phys. Chem. A 104, 4785 (2000)] predict a strong dependence of the macroscopic nonlinear optical susceptibility on the chromophore waist: length aspect ratio in electric-field-poled films arising from interactions between chromophores. It is expected that these interactions will play a role in the absorption characteristics of unpoled films, as well. The spacer groups range in length from diethyl to dihexyl, and each dye is studied over a wide range of concentrations. Among the four dyes studied, a universal dependence of near-IR loss on inhomogeneous broadening of the dye main absorption peak is found. The inhomogeneous width and its concentration dependence are seen to vary with spacer length in a manner characteristic of the near-IR loss-concentration slope at transmission wavelengths of 1.06 and 1.3μm, but not at 1.55μm. The lower wavelength loss behavior is assigned to purely Gaussian broadening, and is described by classical mixing thermodynamic quantities based on the Marcus theory of inhomogeneous broadening [R. A. Marcus, J. Chem. Phys. 43, 1261 (1965)], modeled as a convolution of dye-dye dipole broadening and dye-polymer van der Waals broadening. The Gaussian dipole interactions follow a Loring dipole-broadening description [R. F. Loring, J. Phys. Chem. 94, 513 (1990)] dominated by the excited-state dipole moment, and have a correlated homogeneous broadening contribution. The long-wavelength loss behavior has a non-Gaussian dye-dye dipole contribution which follows Kador’s broadening analysis [L. Kador, J. Chem. Phys. 95, 5574 (1991)], with a net broadening described by a convolution of this term with a Gaussian van der Waals interaction given by Obata et al. [M. Obata, S. Machida, and K. Horie, J. Polym. Sci. B 37, 2173 (1999)], with each term governed by the dye spacer length. A minimum in broadening and loss-concentration slope at a spacer length of four carbons per alkyl at all wavelengths has important consequences for practical waveguide devices, and is of higher aspect ratio than the spherical limit shown by Robinson and Dalton to minimize dipole interactions under a poling field.
Test of models for electron transport in laser produced plasmas
Authors: Colombant D. G. , Manheimer W. M. , Busquet M.
Published: June 2005

This paper examines five different models of electron thermal transport in laser produced spherical implosions. These are classical, classical with a flux limit f, delocalization, beam deposition model, and Fokker–Planck solutions. In small targets, the results are strongly dependent on f for flux limit models, with small f’s generating very steep temperature gradients. Delocalization models are characterized by large preheat in the center of the target. The beam deposition model agrees reasonably well with the Fokker–Planck simulation results. For large, high gain fusion targets, the delocalization model shows the gain substantially reduced by the preheat. However, flux limitation models show gain largely independent of f, with the beam deposition model also showing the same high gain.
The influence of potential softness on the transport coefficients of simple fluids
Authors: Heyes D. M. , Brańka A. C.
Published: June 2005

This study explores the effects of interaction softness on the transport properties of simple fluids. The transport coefficients of soft-sphere fluids in which the particles interact via the potential, ϕ(r)=ϵ(r∕σ)−n, with n in the range from 6 to 1152, have been calculated by molecular-dynamics computer simulation. The self-diffusion coefficient D shear viscosity ηs, bulk viscosity ηb, and thermal conductivity λ were computed over a wide packing fraction range. It was found that the Batschinski–Hildebrand expressions, in which D, ηs−1, ηb−1, and λ−1 are assumed to have a linear dependence on the molar volume, represent the data quite well for all n, although least well for the thermal conductivity. The density for which, on extrapolation, each of these quantities is zero, increases with the softness of the interaction (or ∼n−1), suggesting that the effective hard-sphere diameter decreases with increasing softness in the small n limit. This treatment leads to simple empirical formulas for the effect of density and n on the effective hard-sphere diameter and packing fraction (in an intermediate range) and the four transport coefficients of these fluids.
Mass transport phenomena during lithographic polymerization of nematic monomers monitored with interferometry
Authors: van der Zande Bianca M. I. , Steenbakkers Jan , Lub Johan , Leewis Christian M. , Broer Dirk J.
Published: June 2005

Photopolymerization of liquid-crystalline diacrylates is a versatile tool to make optical films for liquid-crystal display (LCD) enhancement. The constant drive towards LCD’s having an improved front-of-screen performance demands optical films with properties that can be adjusted on (sub) pixel level. Birefringent films made from liquid-crystalline diacrylates allow for the required adjustment of the optical property on (sub) pixel level. In this paper we report on the composition of the acrylate mixture that results in planarly aligned nematic films usable as optical retarder in transflective LCD’s as well as the mass transport phenomena that take place during heating of a mask-exposed birefringent film of liquid-crystalline diacrylates. The mass transport phenomena are studied by interferometry as a function of temperature and time. Upon heating a pronounced surface corrugation arises from the latent image formed during the mask exposure. The surface profile largely depends on lateral feature sizes. For 1×1-mm2 areas the exposed areas rise compared to the nonexposed areas, whereas the opposite is observed for 100×100-μm2 areas. Finally, the direction of the mass transport depends on the molecular orientation of the liquid-crystalline diacrylate. The protrusion formed by lengthwise diffusion is 1.7 times higher than that formed by sidewise diffusion.
Density-functional theory study of electric and magnetic properties of hexafluorobenzene in the vapor phase
Authors: Rizzo Antonio , Cappelli Chiara , Jansík Branislav , Jonsson Dan , Sałek Paweł , Coriani Sonia , Wilson David J. D. , Helgaker Trygve , Ågren Hans
Published: June 2005

A series of electric and magnetic properties of hexafluorobenzene have been calculated, including the electric dipole polarizability, magnetizability, electric quadrupole moment, and nonlinear mixed electric dipole-magnetic dipole-electric quadrupole hyperpolarizabilities needed to obtain estimates of the Kerr, Cotton-Mouton, Buckingham, Jones, and magnetoelectric birefringences in the vapor phase. Time-dependent density-functional theory was employed for the calculation of linear-, quadratic, and cubic response functions. A number of density functionals have been considered, along with Sadlej’s triple-ζ basis set and the augmented correlation-consistent polarized valence double zeta and augmented correlation-consistent polarized valence triple zeta basis sets. Comparisons have been made with experiment where possible. The analysis of results allows for an assessment of the capability of time-dependent density-functional theory for high-order electromagnetic properties of an electron-rich system such as hexafluorobenzene.
Optimized cleaning method for producing device quality InP(100) surfaces
Authors: Sun Yun , Liu Zhi , Machuca Francisco , Pianetta Piero , Spicer William E.
Published: June 2005

A very effective, two-step chemical etching method to produce clean InP(100) surfaces when combined with thermal annealing has been developed. The hydrogen peroxide∕sulfuric acid-based solutions, which are successfully used to clean GaAs(100) surfaces, leave a significant amount of residual oxide on the InP surface which cannot be removed by thermal annealing. Therefore, a second chemical etching step is needed to remove the oxide. We found that strong acid solutions with HCl or H2SO4 are able to remove the surface oxide and leave the InP surface passivated with elemental P which is, in turn, terminated with H. This yields a hydrophobic surface and allows for lower temperatures to be used during annealing. We also determined that the effectiveness of oxide removal is strongly dependent on the concentration of the acid. Surfaces cleaned by HF solutions were also studied and result in a hydrophilic surface with F-terminated surface In atoms. The chemical reactions leading to the differences in behavior between InP and GaAs are analyzed and the optimum cleaning method for InP is discussed.
Bright green electroluminescence from Tb3+ in silicon metal-oxide-semiconductor devices
Authors: Sun J. M. , Skorupa W. , Dekorsy T. , Helm M. , Rebohle L. , Gebel T.
Published: June 2005

Bright green electroluminescence with luminance up to 2800cd∕m2 is reported from indium-tin-oxide∕SiO2:Tb∕Si metal-oxide-semiconductor devices. The SiO2:Tb3+ gate oxide was prepared by thermal oxidation followed by Tb+ implantation. Electroluminescence and photoluminescence properties were studied with variations of the Tb3+ ion concentration and the annealing temperature. The optimized device shows a high external quantum efficiency of 16% and a luminous efficiency of 2.1lm∕W. The excitation processes of the strong green electroluminescence are attributed to the impact excitation of the Tb3+ luminescent centers by hot electrons and the subsequent crossrelaxation from D35 to D45 energy levels. Light-emitting devices with micrometer size fabricated by the standard metal-oxide-semiconductor technology are demonstrated.
Enhanced step coverage by oblique angle physical vapor deposition
Authors: Karabacak Tansel , Lu Toh-Ming
Published: June 2005

We present the use of an oblique angle physical vapor deposition (OAPVD) technique with substrate rotation to obtain conformal thin films with enhanced step coverage on patterned surfaces. We report the results of ruthenium (Ru) films sputter deposited on trench structures with aspect ratio ∼2 and show that OAPVD with an incidence angle less that 30° with respect to the substrate surface normal one can create a more conformal coating without overhangs and voids compared to that obtained by normal incidence deposition. A simple geometrical shadowing effect is presented to explain the results. The technique has the potential of extending the present PVD technique to future chip interconnect fabrication.
Recombinative plasma in electron runaway discharge
Authors: Kuznetsov Yu. K. , Galvão R. M. O. , Usuriaga O. C. , Krasheninnikov S. I. , Soboleva T. K. , Tsypin V. S. , Fonseca A. M. M. , Ruchko L. F. , Sanada E. K.
Published: June 2005

Cold recombinative plasma is the basic feature of the new regime of runaway discharges recently discovered in the Tokamak Chauffage Alfvén Brésilien tokamak [R. M. O. Galvão et al., Plasma Phys. Controlled Fusion 43, 1181 (2001)]. With low plasma temperature, the resistive plasma current and primary Dreicer process of runaway generation are strongly suppressed at the stationary phase of the discharge. In this case, the runaway avalanche, which has been recently recognized as a novel important mechanism for runaway electron generation in large tokamaks, such as International Thermonuclear Experimental Reactor, during disruptions, and for electric breakdown in matter, is the only mechanism responsible for toroidal current generation and can be easily observed. The measurement of plasma temperature by the usual methods is a difficult task in fully runaway discharges. In the present work, various indirect evidences for low-temperature recombinative plasma are presented. The direct observation of recombinative plasma is obtained as plasma detachment from the limiter. The model of cold recombinative plasma is also supported by measurements of plasma density and Hα emission radial profiles, analysis of time variations of these parameters due to the relaxation instability, estimations of plasma resistivity from voltage spikes, and energy and particle balance calculations.
Laser terahertz emission system to investigate hydrogen gas sensors
Authors: Kiwa Toshihiko , Tsukada Keiji , Suzuki Masato , Tonouchi Masayoshi , Migitaka Sonoko , Yokosawa Koichi
Published: June 2005

A laser terahertz emission system is proposed to investigate the catalytic metal/semiconductor interfaces of hydrogen sensors. Samples were fabricated by depositing a catalytic metal thin film on a semi-insulating silicon substrate. A femtosecond laser was used to radiate terahertz waves from the sample in a gas cell filled with a hydrogen and nitrogen gas mixture. The peak amplitude of the terahertz waves decreased with increasing hydrogen concentration. We also fabricated a metal-oxide-semiconductor field effect transistor hydrogen sensor, and compared its properties with the terahertz radiation properties. These results suggest that the laser terahertz emission system is a potential tool to investigate catalytic metal/semiconductor interfaces.
Preparation of tungsten oxide nanowires from sputter-deposited WCx films using an annealing/oxidation process
Authors: Wang Shui-Jinn , Chen Chao-Hsuing , Ko Rong-Ming , Kuo Yi-Cheng , Wong Chin-Hong , Wu Chien-Hung , Uang Kai-Ming , Chen Tron-Min , Liou Bor-Wen
Published: June 2005

The self-synthesis of tungsten oxide (W18O49) nanowires on sputter-deposited WCx films using a simple annealing/oxidization process was reported. It was found that thermal annealing of WCx films at 680°C for 30min in nitrogen followed by oxidation at 450°C for 30min in pure oxygen would yield dense and well-crystallized monoclinic W18O49 (010) nanowires with a typical length/diameter of about 0.15–0.2μm∕10–20nm. The formation of W18O49 nanowires is attributed to the nuclei of immature W2C nanowires experiencing a regrowth process, accompanied by carbon depletion and the oxidization of tungsten during the subsequent oxidization process.
Crystal Distortion in Magnetic Compounds
Authors: Kanamori Junjiro
Published: June 2005

The crystal distortion which arises from the Jahn-Teller effect is discussed in several examples. In the case of compounds containing Cu2+ or Mn3+ at octahedral sites, the lowest orbital level of these ions is doubly degenerate in the undistorted structure, and there is no spin-orbit coupling in this level. It is shown that, introducing a fictitious spin to specify the degenerate orbital states, we can discuss the problem by analogy with the magnetic problems. The “ferromagnetic” and “antiferromagnetic” distortions are discussed in detail. The transition from the distorted to the undistorted structure is of the first kind for the former and of the second kind for the latter. Higher approximations are discussed briefly. In compounds like FeO, CoO, and CuCr2O4, the lowest orbital level is triply degenerate, and the spin-orbit coupling is present in this level. In this case the distortion is dependent on the magnitude of the spin-orbit coupling relative to the strength of the Jahn-Teller effect term. The distortion at absolute zero temperature and its temperature dependence are discussed.
Magnetic Interactions and Distribution of Ions in the Garnets
Authors: Geller S.
Published: June 2005

Since the discovery of the magnetic yttrium and rare earth iron garnets, a systematic investigation has been made of interactions of magnetic ions and the distribution of both magnetic and non-magnetic ionsin the garnets. The results of substitution of the tetravalent tin for Fe3+ ion in yttrium-iron garnet (balanced by substitution of Ca2+ for Y3+ ions) have led to the development by Gilleo of a statistical interaction theory which accounts well for the spontaneous magnetizations and Curie temperatures of the system. This theory has been further strengthened by results from zirconium substituted yttrium-iron garnets and by its successful extension to substituted rare earth iron garnets.

In the course of our investigations, many new garnets have been discovered. Several of these have enabled us to observe directly interactions between magnetic ions in dodecahedral and octahedral sites, dodecahedral and tetrahedral sites, octahedral sites only and tetrahedral sites only. The work on the garnets has also already been adequately extensive to lead to the establishment of some rather simple rules pertaining to site preference of ions entering the garnets.
Resonance Experiments with Single Crystal Yttrium Iron Garnets in Pulsed Magnetic Fields
Authors: Stiglitz Martin R. , Morgenthaler Frederic R.
Published: June 2005

A crystal sphere of YIG was placed in either a doubly resonant transmission type coaxial cavity or into a nonresonant transmission line device and biased with a dc magnetic field. A low power microwave signal in the S band frequency range (cw or pulsed) was used to excite resonance. Current pulses of approximately 1 μsec duration and low duty cycle were sent through a low impedance coil that was wound around the cavity or transmission line respectively. These pulses induced pulsed magnetic fields of the order of 1000 gauss, which (vectorially) added to the existing dc field.

A microwave receiver, attached to the cavity output, detected weak oscillations at higher or lower frequencies. Shifts of 280 Mc have been obtained with the cavity, and shifts of 1280 Mc above and 530 Mc below the driving frequency have been obtained with the transmission type device.

The detected signal is associated with either the rise of the current pulse, or the decay, or two signals may appear simultaneously corresponding respectively to the rise and decay. This depends upon the angular relation of the dc field with respect to the cavity or transmission line.
Samarium Substitutions in Yttrium Iron Garnet
Authors: Cunningham J. Richard , Anderson Elmer E.
Published: June 2005

Polycrystalline garnets of the form (3 − x)Y2O3·xSm2O3·5Fe2O3 have been prepared where x was varied from 0 to 3 in six steps. Lattice constants were found to vary linearly from 12.374±0.005 A for yttrium irongarnet (x = 0) to 12.533±0.005 A for samarium iron garnet (x = 3). The theoretical x-ray densities were calculated and vary from 5.17 gms/cc for x = 0 to 6.22 gms/cc for x = 3. Magnetic moments were measured from 77° to 600°K. No magnetic compensation points were observed. The Curie temperature for these garnets is 570±10°K. Thermal magnetization curves for this series indicate that samarium substitution for yttrium produces very little change in the magnetization. The relative complex initial permeability was measured from dc to 2 kMc for several temperatures. The results of these measurements are discussed briefly.
Specific Heat of Some Rare Earth Iron Garnets and YIG at Low Temperatures
Authors: Meyer Horst , Harris A. B.
Published: June 2005

Heat capacity measurements of the iron garnets of Y, Gd, Er, Ho, and Yb between 1.4° and 20°K are presented. Below 5°K, the specific heat of YIG can be represented by the sum of a lattice term proportional to T3 and the spin-wave contribution 2.15 × 10−3T32 joules/mole-deg. This last term agrees satisfactorily with that calculated from a spin-wave analysis, in which the exchange interaction coefficients were those derived from Pauthenet's magnetization data. The results of the magnetic specific heat of the rare earth ions could be interpreted in terms of a Weiss molecular field acting on these ions. For Gd3+ and Yb3+, this field was found to be, respectively, about 3.0 × 105 and 1.5 × 105 oe below 20°K, in satisfactory agreement with that derived from Pauthenet's data.
On the Resolution of Brown's Paradox
Authors: Shtrikman S. , Treves D.
Published: June 2005

The possibility is examined that Brown's paradox results from the assumption that the shape of the crystal considered is ellipsoidal. It is argued that the large local demagnetizing fields developed near sharp corners of a uniformly magnetized crystal cause the appearance of closure domains, which serve as nuclei of reverse magnetization, thus lowering the coercive force. A tentative development of these domains upon the application of a reverse field is given.
Internal Structure of Bloch Walls
Authors: Shtrikman S. , Treves D.
Published: June 2005

The subdivision of a Bloch wall into a periodic structure of right- and left-hand walls observed by Williams and Goertz and by DeBlois and Graham is shown to be caused by the self-magnetostatic energy of the wall. The period of this structure is calculated by an approximate minimization of the energies involved. The results compare favorably with experimental evidence.
Magnetic Anisotropy and Magnetostriction of Ordered and Disordered Cobalt-Iron Alloys
Authors: Hall R. C.
Published: June 2005

The magnetic anisotropy and magnetostriction of single crystals of alloys between 25 weight % and 59 weight % cobalt in iron have been determined in the disordered and ordered states. The magnetostrictionis large and positive for all alloys in both states of order (up to 150×10−6 for λ100 and 40×10−6 for λ111). The magnetic anisotropy becomes zero near 41% Co for the disordered state. Ordering shifts the zero-anisotropy composition to about 50% Co.
Initial Susceptibility Spectra of Permalloy Films
Authors: Soohoo R. F.
Published: June 2005

The initial susceptibility of Permalloy films from 100 to 10000 Mc/sec is investigated theoretically and experimentally. The exact boundary value problem of a film placed in a rectangular cavity is solved. This result is compared with the simpler solution obtained by means of the Bethe-Schwinger perturbation formula. As may be expected, the exact solution reduces to that obtained from perturbation theory when the film thickness and the value of the initial susceptibility are sufficiently small. In a self-consistent way,we show that exchange effects can sometimes be neglected as far as initial susceptibility values are concerned.
Effects of Surface Irregularities on Single Crystal Resonance Parameters
Authors: Buffler C. R.
Published: June 2005

Measurements of ferromagnetic resonance line width, and anisotropy of line width of yttrium iron,garnet, and manganese zinc ferrite single crystals as a function of surface irregularities from 8 to 75 μ, and frequency from 2 to 16 kMc are presented. These measurements indicate that the frequency dependence of the line width and line width anisotropy in these materials for varying degrees of surface roughness can be interpreted with respect to spin wave scattering theories. In this case, the surface irregularities act as scattering centers for the uniform precession, causing a loss of energy into degenerate spin wave states with wavelengths corresponding to the size of the irregularities.
Direct-Current Measurements on Tape-Wound Cores
Authors: Barker R. C. , Brownell R. M.
Published: June 2005

This paper reports hysteresis-loop measurements made on tape-wound cores of commercial-grade grain-oriented 50Ni-50Fe material at very low domain wall velocities. The experimental equipment includes a low-output-impedance core driver, a low-drift electronic integrator, and a 30 in.× 30 in. X-Y recorder. The duration of a complete flux reversal can be varied between 5 seconds and 30 minutes. The rate-of-change of flux during a reversal can be held constant within 1%, so that variations in the ease of domain wall motion (which appear as Barkhausen discontinuities in conventional measurements) are constrained to appear as variations of magnetomotive force. The coarse structure of these variations is repeatable on successive measurements; the fine structure, for the most part is not.

In addition to showing these variations of mmf, the experimental arrangement displays minor loops in their correct locations with respect to the major loop. These measurements indicate that, under dc conditions, flux changes always begin at the inner circumference of the core, as predicted by a previously proposed model of flux change in polycrystalline tapes. Many other aspects of these minor-loop measurements can be explained by this model,which is currently being further developed.

On the basis of the model, the recorded variations in mmf can easily be used to find the variations in the energy required to move domain walls in various portions of the core, under conditions of constant rate-of-change of flux. (Under such conditions,the product of wall velocity and wall area is a constant.) The repeatability of the coarse variations indicates their dependence on local metallurgical variations within the core. The nonrepeatability of the fine variations probably indicates a randomness in the configuration of the domain walls as they pass through the same region on successive measurements.
Square Loop Properties of Copper-Manganese Ferrites
Authors: Weisz R. S. , Brown D. L.
Published: June 2005

A survey of magnetic properties for the system CuFe2O4-MnFe2O4-Mn3O4 is reported. Saturation flux density, Curie temperature, coercivity, hysteresis loop squareness, and switching constant were determined for 60 compositions. A large compositional area having square loop properties was found. Apparently, both divalent Cu and trivalent mu contribute to squareness. Switching constant was found to decrease markedly with increasing manganese content to a low in the neighborhood of 0.6 oe-μsec.

Coincident-current memory cores made from appropriate Cu-Mn ferrites have properties very similar to conventional Mg-Mn ferrites but at significantly lowered driving currents.
Flux Reversal by Noncoherent Rotation in Magnetic Films
Authors: Harte K. J.
Published: June 2005

A model of magnetization reversal in thin ferromagnetic films is proposed. The model is based on a small angular dispersion (∼3°) in the film plane of the axis of planar anisotropy. The dynamical effects of this dispersion are important when the switching field (Hs) is of the order of the anisotropy field, fall off rapidly with increasing Hs, and include a two- to threefold increase in the switching coefficient for bias field large enough to insure unidirectional rotation. In addition, it is shown that the transverse flux reaches its maximum before the longitudinal flux is one-half switched. These results are in reasonable agreement with experiment.
Influence of Nearby Conductors on Thin Film Switching
Authors: Eggenberger J. S.
Published: June 2005

The usual concept of a thin film or other open flux path magnetic element consists of the material itself closely encircled by drive and sense conductors. Strips of conductor of width approximately that of the element are attractive for several reasons, i.e., low resistance, low skin effect, and low line impedance. However,these strips, being closely coupled to the element, can severely influence its dynamic properties by means of induced eddy currents.

These conductors manifest themselves in three ways:

1. A slowing of the switching due to the air return flux path of the element passing through a conductorand being damped.

2. A dynamic distortion of the air return flux due to shielding effects.

3. A dynamic distortion of an applied field due to shielding effects.

All of these effects can be detrimental to the operation of the element. In this paper, approximate calculations are presented to show the extent of these effects. The geometry considered is that of a “conventional”flat thin film element, driven and sensed by strip transmission lines. Several drive and sense configurations are considered, and experimental evidence is presented in support of these calculations. Although the cases considered are somewhat arbitrary, the methods and many of the results are applicable to other cases of utilization of open flux path elements.
Preferred Orientation and Ordering in Evaporated Films of Fe, Ni, and Fe-Ni
Authors: Adamsky R. F.
Published: June 2005

Studies of the effect of evaporation angle on orientation tendencies have shown the effect to be insignificant for certain evaporation conditions. Thickness gradients and particle size variations are the major effects of variation of incidence angle in these experiments. Slight degrees of preferred orientation in the form of [111] fiber axes have been found for Fe, Ni, and permalloy films deposited on heated substrates. Annealing experiments have shown the presence of superlattice ordering in permalloy films held for short periods of time at 200°C.
Investigations into the Origin of Anisotropy in Oblique-Incidence Films
Authors: Cohen M. S. , Huber E. E. , Weiss G. P. , Smith D. O.
Published: June 2005

Experimental evidence is presented which shows that the magnetic anisotropy of oblique-incidence Permalloy and iron films is not caused by an inclined texture axis or anisotropic strain. Electron diffraction and microscopy have not yet revealed anisotropy in the crystalline microstructure of these films. These techniques have also thus far failed to reveal the existence of agglomeration of the crystallites into small groups having anisotropic geometric shapes. Magnetic anisotropy, on the other hand, was observed in Permalloy films deposited at normal incidence on non-magnetic metal films deposited at oblique incidence;this would suggest such an agglomeration mechanism. There is also some indication that oxygen may play a role in oblique-incidence magnetic anisotropy.
Magneto Structural Studies on Gadolinium-Iron Alloys
Authors: Vickery R. C. , Sexton W. C. , Novy V. , Kleber E. V.
Published: June 2005

Magnetic and constitutional data have been established for a series of alloys in the gadolinium-iron system, ranging from 2–98% Fe. Seven intermetallic compounds have been found and some correlation has been derived between their crystal structures and magnetic properties. The cubic Gd2Fe3 compound has been found to exhibit highest magnetization values of the intermetallics and comparison of data on the Gd-Co and Gd-Ni compounds suggests that presence of the 2:3 structure (not found in the Gd-Ni system) is necessary for the development of ferromagnetism in these systems.
Nucleation Experiments on Thin Magnetic MnBi Films
Authors: Mayer Ludwig
Published: June 2005

Experiments devised to provide information about the nucleation probability of ferromagnetic MnBi films are described. These experiments revealed that uniform magnetic MnBi films grow from only a few randomly distributed nucleation sites. Thus nucleation is of considerable importance in the preparation of magnetic MnBi films. Further studies aimed at controlling this nucleation behavior are therefore indicated. First experiments directed toward this goal showed that 100% nucleation occurs if the Mn-Bi layer which is to be transformed is deposited on an already formed magnetic MnBi film. The magnetic field of this pre-magnetized MnBi film substrate is the cause for the development of extremely large domains but the high efficiency of nucleation seems to stem simply from the direct contact with the already finished MnBi filmsubstrate.
Pulsed Ferrimagnetic Microwave Generator
Authors: Elliott B. J. , Schaug-pettersen T. , Shaw H. J.
Published: June 2005

The idea of making a solid-state generator using a ferrimagnetic material to convert energy from a pulsed dc magnetic field into microwave radiation has been studied by several workers. Recent theoretical studies have disclosed serious basic problems for such devices. This paper describes initial experiments on a device which avoids the principal difficulties. It uses an rf input signal together with a pulsed dc magnetic field to generate microwave pulses at a frequency higher than the input frequency. An input signal at 2.4 kMc/sec and a pulsed magnetic field of 150 gauss were used to generate a pulsed output signal at 2.8 kMc/sec.
Long-term cortical plasticity evoked by electric stimulation and acetylcholine applied to the auditory cortex
Authors: Ma Xiaofeng , Suga Nobuo
Published: June 2005

Auditory fear conditioning with tone bursts followed by electric leg stimulation activates neurons not only in the auditory and somatosensory systems but also in many other regions of the brain and elicits shifts in the best frequencies (BFs) of collicular and cortical neurons, i.e., reorganization of the frequency (co-chleotopic) maps in the inferior colliculus and auditory cortex (AC). What are the neural elements minimally necessary for evoking long-term cortical BF shifts? We found that: (
i
) both electric stimulation and acetylcholine applied to the AC evoke the long-term cortical BF shift as does the conditioning; (
ii
) both electric stimulation of the AC and acetylcholine applied to the inferior colliculus increase the short-term collicular BF shift evoked by the cortical electric stimulation but do not change it into long-term; and (
iii
) as this short-term collicular BF shift is blocked by atropine, the development of the long-term cortical BF shift becomes slow and small. Therefore, the most essential neural elements for evoking the long-term cortical BF shift are the AC, corticofugal feedback and the cholinergic nucleus. Our current data support the Gao–Suga model, which hypothesizes that the small short-term cortical BF shifts are evoked by tonal stimuli without the association of conditioned and unconditioned stimuli in the multisensory thalamic nuclei and that these BF shifts are augmented and changed into the large long-term BF shifts by cholinergic neurons.
Wnt-dependent regulation of inner ear morphogenesis is balanced by the opposing and supporting roles of Shh
Authors: Riccomagno Martin M. , Takada Shinji , Epstein Douglas J.
Published: June 2005

The inner ear is partitioned along its dorsal/ventral axis into vestibular and auditory organs, respectively. Gene expression studies suggest that this subdivision occurs within the otic vesicle, the tissue from which all inner ear structures are derived. While the specification of ventral otic fates is dependent on Shh secreted from the notochord, the nature of the signal responsible for dorsal otic development has not been described. In this study, we demonstrate that Wnt signaling is active in dorsal regions of the otic vesicle, where it functions to regulate the expression of genes (Dlx5/6andGbx2) necessary for vestibular morphogenesis. We further show that the source of Wnt impacting on dorsal otic development emanates from the dorsal hindbrain, and identify Wnt1 and Wnt3a as the specific ligands required for this function. The restriction of Wnt target genes to the dorsal otocyst is also influenced by Shh. Thus, a balance between Wnt and Shh signaling activities is key in distinguishing between vestibular and auditory cell types.
Guanosine triphosphate acts as a cofactor to promote assembly of initial P-element transposase–DNA synaptic complexes
Authors: Tang Mei , Cecconi Ciro , Kim Helen , Bustamante Carlos , Rio Donald C.
Published: June 2005

P transposable elements in Drosophila are members of a larger class of mobile elements that move using a cut-and-paste mechanism. P-element transposase uses guanosine triphosphate (GTP) as a cofactor for transposition. Here, we use atomic force microscopy (AFM) to visualize protein-DNA complexes formed during the initial stages of P-element transposition. These studies reveal that GTP acts to promote assembly of the first detectable noncovalent precleavage synaptic complex. This initial complex then randomly and independently cleaves each P-element end. These data show that GTP acts to promote protein-DNA assembly, and may explain why P-element excision often leads to unidirectional deletions.
p21WAF1/Cip1 is a negative transcriptional regulator of Wnt4 expression downstream of Notch1 activation
Authors: Devgan Vikram , Mammucari Cristina , Millar Sarah E. , Brisken Cathrin , Dotto G. Paolo
Published: June 2005

In keratinocytes, the cyclin/CDK inhibitor p21WAF1/Cip1 is a direct transcriptional target of Notch1 activation; loss of either the p21 or Notch1 genes expands stem cell populations and facilitates tumor development. The Notch1 tumor-suppressor function was associated with down-regulation of Wnt signaling. Here, we show that suppression of Wnt signaling by Notch1 activation is mediated, at least in part, by down-modulation of Wnts gene expression. p21 is a negative regulator of Wnts transcription downstream of Notch1 activation, independently of effects on the cell cycle. More specifically, expression of the Wnt4 gene is under negative control of endogenous p21 both in vitro and in vivo. p21 associates with the E2F-1 transcription factor at the Wnt4 promoter and causes curtailed recruitment of c-Myc and p300, and histone hypoacetylation at this promoter. Thus, p21 acts as a selective negative regulator of transcription and links the Notch and Wnt signaling pathways in keratinocyte growth control.
Individual Differences in Applicant Reactions: A Job‐Search Perspective
Authors: LaHuis David M.
Published: June 2005

This study used three variables from a self‐regulatory job‐search framework to investigate individual differences in the relationship between applicants' perceived procedural fairness of selection tests and job‐pursuit intentions. Employment commitment, job‐search self‐efficacy, and motivational control were hypothesized to moderate the procedural fairness – job‐pursuit intentions relationship while controlling for pretest attitudes and perceived performance. Applicants (N=291) for entry‐level clerical jobs with large federal agencies completed pretest and posttest surveys. Results suggested that only job‐search self‐efficacy and motivational control moderated the relationship between perceived procedural fairness and job‐pursuit intentions. The relationship was stronger for applicants with higher levels of job‐search self‐efficacy and lower levels of motivational control.