bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupled response of the inner magnetosphere and ionosphere on 17 April 2002
Authors: Goldstein J. , Burch J. L. , Sandel B. R. , Mende S. B. , C:son Brandt P. , Hairston M. R.
Published: March 2005

We present an observational study of the global dynamics of the plasmasphere, aurora, ring current, and subauroral ionosphere on 17 April 2002 during a substorm. Global observations by the Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE) and in situ observations by DMSP F13 provide a comprehensive view of the coupled response of the inner magnetosphere and ionosphere. At 1900 UT a substorm onset initiated a sunward convective impulse, which caused a ring current injection. The motion of this impulse past the plasmasphere caused ripples to propagate along the plasmapause, eastward and westward from premidnight magnetic local time (MLT). The motion of the ripples agrees exceptionally well with the motion of the aurora and the ring current, implying strong coupling. The westward moving ripple (on the duskside) participated in a two‐phase plasmapause undulation effect. In the first phase (1915 UT to 1936 UT), a mild 0.4–0.5 RE bulge formed near 2000 MLT, probably caused by an E‐field induced by local reduction of the magnetic field by the ring current pressure increase. In the second phase (1936 UT to 2037 UT) this mild bulge was removed by a subauroral polarization stream (SAPS) westward flow that stripped away the outer 1 RE of the duskside plasmasphere. The SAPS effect was observed in the ionosphere by DMSP between about 1930 UT and 2000 UT and is evident in vector E‐fields inferred from plasmapause motion. All the observations of this event suggest strong coupling among the plasma populations of the magnetosphere‐ionosphere system. This event represents the first identification of the directly observed global plasmaspheric effects of a substorm‐driven impulse, the SAPS flow channel, and the ring‐current magnetic field reduction.
Significance of stress transfer in time‐dependent earthquake probability calculations
Authors: Parsons Tom
Published: March 2005

A sudden change in stress is seen to modify earthquake rates, but should it also revise earthquake probability? Data used to derive input parameters permit an array of forecasts; so how large a static stress change is required to cause a statistically significant earthquake probability change? To answer that question, effects of parameter and philosophical choices are examined through all phases of sample calculations. Drawing at random from distributions of recurrence‐aperiodicity pairs identifies many that recreate long paleoseismic and historic earthquake catalogs. Probability density functions built from the recurrence‐aperiodicity pairs give the range of possible earthquake forecasts under a point process renewal model. Consequences of choices made in stress transfer calculations, such as different slip models, fault rake, dip, and friction are tracked. For interactions among large faults, calculated peak stress changes may be localized, with most of the receiving fault area changed less than the mean. Thus, to avoid overstating probability change on segments, stress change values should be drawn from a distribution reflecting the spatial pattern rather than using the segment mean. Disparity resulting from interaction probability methodology is also examined. For a fault with a well‐understood earthquake history, a minimum stress change to stressing rate ratio of 10:1 to 20:1 is required to significantly skew probabilities with >80–85% confidence. That ratio must be closer to 50:1 to exceed 90–95% confidence levels. Thus revision to earthquake probability is achievable when a perturbing event is very close to the fault in question or the tectonic stressing rate is low.
Wavelet approach to improvement of gravity field–geoid modeling for Japan
Authors: Kuroishi Yuki , Keller Wolfgang
Published: March 2005

An improved gravimetric geoid model for Japan, JGEOID2004, on a grid of 1 × 1.5 minutes, was constructed by the one‐dimensional fast Fourier transform method with EGM96 as a foundation model. The model geoid heights in the nontidal system refer to the GRS80 ellipsoid aligned in the ITRF94 (epoch 1997.0). Newly acquired terrestrial gravity data supplemented the data gaps of the previous model, JGEOID2000. A “semidiscrete” wavelet analysis/reconstruction with two‐dimensional (2‐D) Halo wavelets were developed and successfully applied to a combination of marine gravity data and an altimetric gravity model, KMS02. The method is used to localize 2‐D signal components in the spatio‐frequency domain and to screen them as a locally adjustable band‐pass filter. Compared with 816 GPS/leveling benchmarks, JGEOID2004 showed significant improvement over JGEOID2000: the standard deviation of the differences from the best fit planes is reduced from 15.3 cm to 9.2 cm. Substantial localized errors, which are due to systematic errors of the marine gravity data as well as to data gaps on land and in the inland sea, were effectively removed.
Inversion tectonics during continental rifting: The Turkana Cenozoic rifted zone, northern Kenya
Authors: Le Gall B. , Vétel W. , Morley C. K.
Published: March 2005

Remote sensing data and revised seismic reflection profiles provide new insights about the origin of inverted deformation within Miocene‐Recent basins of the Turkana rift (northern Kenya) in the eastern branch of the East African rift system. Contractional structures are dominated by weakly inverted sets of fault blocks within <3.7 Myr old synrift series. Most of reverse extensional faults involve components of oblique‐slip, whereas associated hanging wall folds are characterized by large wavelength upright folding. The area of basin inversion is restricted to a 40 × 100 km elongated zone overlying a first‐order N140°E trending fault zone in the basement, referred to as the N'Doto transverse fault zone (NTFZ). In the proposed kinematic model, inversion tectonics is assigned to permutation of principal stress axes (σ1/σ2) in addition to the clockwise rotation of extension (from nearly N90°E to N130°E) during Pliocene. The transition from pure extension (Miocene) to a wrench faulting regime (Pliocene) first results in the development of T‐type fault networks within a dextrally reactivated shear zone (NTFZ). Inversion tectonics occurred later (<3.7 Ma) in response to a still rotated (∼20°) shortening axis (σ1) oriented N40°E that caused the oblique compression of earlier (NS to N20°E) extensional structures within the NTFZ. The origin of basin inversion and strain concentration in the Turkana rift is thus directly linked to a crustal weakness zone, transverse to the rift axis, and involving steep prerift anisotropies.
An analysis of hydraulic conductivity scale effects in granite (Full‐scale Engineered Barrier Experiment (FEBEX), Grimsel, Switzerland)
Authors: Martinez‐Landa Lurdes , Carrera Jesús
Published: March 2005

Different types of hydraulic tests (pulse, recovery, cross‐hole, and tunnel inflow measurements) have been performed in a low‐permeability fractured granite around the Full‐scale Engineered Barrier Experiment (FEBEX) gallery in Grimsel (Switzerland). We have interpreted the tests using conventional methods that treat the medium as a homogeneous one. Results display scale effects. Hydraulic conductivities increase, by orders of magnitude, with the volume of rock tested (from pulse to cross‐hole tests). The objective of our work is to show that this scale effect is apparent. It reflects the limitations of the equivalent hydraulic conductivity derived from the homogeneous model interpretation of the tests. For this purpose we built a three‐dimensional model for the joint interpretation of cross‐hole tests. The model represents explicitly the conductive fractures and treats the rest as an equivalent porous medium (matrix). Transmissivity values used in the model to represent fractures are consistent with those derived from cross‐hole tests and the few single‐hole tests at intervals intersecting fractures. On the other hand, matrix hydraulic conductivities are consistent with the remaining single‐hole, short‐time tests. This model can also be used to simulate observed heads and gallery inflows. In summary, the final model is consistent with all the relevant measurements, taken at different support scales. This provides some insight into the issue of scale effects, which has been a topic of debate in the literature. In summary, the majority of small‐scale tests are performed in matrix intervals. Thus any averaging of these values would suggest relatively small effective permeability. Yet large‐scale permeability of the rock is controlled by a few fractures, which provide high connectivity to the system but are intersected by few testing intervals. As a result, large‐scale permeability is qualitatively different and quantitatively larger than small‐scale permeability.
Magnetic structure of Nd3Co29Si4B10
Authors: Zhang Heng , Hofmann M. , Kennedy S. J. , Campbell S. J.
Published: March 2005

The crystal and magnetic structures of the quaternary rare-earth intermetallic compound Nd3Co29Si4B10 have been investigated by neutron diffraction (1.5 and 300K). Rietveld refinements demonstrate that Nd3Co29Si4B10 is isostructural with the Nd3Ni29Si4B10 tetragonal structure and that Nd3Co29Si4B10 has a canted magnetic structure below the ferromagnetic ordering temperature TC=200K. The refinement of the 1.5-K diffraction pattern leads to mean values for the magnetic moments of μCo∼0.4μB and μNd∼2μB at the 2b and 4d sites.
Elimination of defect-induced color instabilities in polymer light-emitting devices
Authors: Mauthner G. , Collon M. , List E. J. W. , Wenzl F. P. , Bouguettaya M. , Reynolds J. R.
Published: March 2005

We demonstrate that utilizing a blue light-emitting oligo(ethylene oxide)-grafted conjugated poly(p-phenylene) (PPP-OR11) as an active layer in a light-emitting electrochemical cell (LEC) preserves a color-stable blue light emission. This is in contrast to the polymer light-emitting diodes (PLEDs) constructed using the same emitting polymer without ionic species, which exhibits a rapid red shifting of the emission to a distinct green. We attribute the color shift to various degradation processes caused by oxidative degradation and aluminum deposition-induced defects in PPP-OR11. The analysis of the degradation processes in the PLEDs shows that the color stability in the LEC is caused by a controlled shift of the recombination zone from the defects including cathode∕polymer interface to an undoped intrinsic zone between the p- and n-type regions of the active layer in the LECs, which qualifies the LEC type devices as a cost-effective approach to the single layer color-stable blue emitting devices.
Angle-resolved mapping of the Fermi velocity in quasi-two-dimensional conductors and superconductors: Probing quasiparticles in nodal superconductors
Authors: Takahashi Susumu , Hill Stephen
Published: March 2005

We describe a technique which enables angle-resolved mapping of the in-plane Fermi velocity (vF) for a quasi-two-dimensional (Q2D) conductor. The method is based on a magnetic resonance effect in the ac conductivity for in-plane magnetic fields, which has recently been successfully applied to a Q2D organic conductor. In this article, we consider the possibility of using this method to probe the normal quasiparticles in nodal superconductors. We briefly explain the principle behind the conductivity resonance, and then present numerical simulations for the normal and superconducting states of a d-wave superconductor.
Half-metallic ferromagnetism in hypothetical wurtzite MBi (M=V, Cr, Mn)
Authors: Zhang Ming , Brück Ekkes , de Boer Frank R. , Wu Guangheng
Published: March 2005

A theoretical study based on a first-principles band-structure calculation is carried out for the hypothetical wurtzite (WZ) MBi (M=V, Cr, Mn). The lattice parameters a and c are determined to be 0.4524nm∕0.7384nm, 0.4496nm∕0.7352nm, and 0.4508nm∕0.7367nm for WZ VBi, CrBi, and MnBi, respectively. The total energy difference between wurtzite structure and NiAs phases are 0.95, 1.01, and 0.99 eV for VBi, CrBi, MnBi, respectively. WZ VBi and CrBi are found to be true half-metallic ferromagnets (HMFs) with the considerably wide half-metallic gap of 0.505 and 0.493 eV, but WZ MnBi is not HMF.
Media magnetization calculation using three-dimensional finite element method in perpendicular magnetic recording
Authors: Xia W.-X. , Yamada T. , Tani K. , Numazawa J. , Muraoka H. , Aoi H. , Nakamura Y.
Published: March 2005

The magnetic medium was included into the finite element method to analyze the recording mechanism of perpendicular magnetic recording. Interactions between the head and medium were accurately considered. The effects of media properties such as the anisotropy field dispersion, the easy axis distribution, and exchange coupling strength on the recording resolution were investigated using the developed program. It was found that reducing the dispersion of anisotropy fields was the most effective way to decrease both the transition width and track width.
Synthesis and complex magnetic susceptibility characterization of magnetic fluids in different liquid carriers
Authors: Ayala Valenzuela O. , Matutes Aquino J. , Betancourt Galindo R. , Rodríguez Fernández O. , Fannin P. C. , Giannitsis A. T.
Published: March 2005

Kerosene, isopar M, and mineral oil based magnetic fluids were prepared. The magnetite nanoparticles have spherical shapes and a mean diameter of 10.2±3.2nm. The complex magnetic susceptibility χ(ω)=χ′(ω)−iχ″(ω) of the magnetic fluids was measured using the transmission line technique applying dc magnetic fields over the range 0–1212Oe over the frequency range 70MHz–6GHz, where resonance and relaxation are present. The resonance frequency fres defined as the frequency at which χ′(ω) goes from positive to negative values ranges from 2.1to5.4GHz. The maximum frequency fmax defined as the frequency at which maximum absorption occurs in χ″(ω) ranges from 1.2to4.8GHz. Anisotropy fields values were also determined.
Permeation of particle through a four-helix-bundle model channel
Authors: Xue Bin , Su Yu , Wang Wei
Published: March 2005

By using molecular dynamics simulation, the dynamic behaviors of particle permeation through a four-helix-bundle model channel are studied. The interior cavity of the four-helix-bundle provides the “routes” for particle permeation. The main structural properties of the model channel are similar to those that appear in natural four-helix-bundle proteins. It is found that the interior structure of the model channel may greatly influence the permeation process. At the narrow necks of the model channel, the particle would be trapped during the permeation. There is a threshold value for the driving force. When the driving force is larger than this threshold value, the mean first permeation time decreases sharply and tends to be saturated. Increasing the temperature of either the model channel or the particle reservoir can also facilitate the permeation. Enhancing the interaction strength between the particle and monomer on the four-helix-bundle model chain will hinder the permeation. Hence, the electrical current which is induced by the particle permeation is a function of the driving force and temperature. It is found that this current increases monotonically as the strength of the driving force or the temperature increases, but decreases as the interaction strength between the particle and monomer increases. It is also found that the larger the friction coefficient, the slower the permeation is. In addition, the multiparticle (or multi-ion) permeation process is also studied. The permeation of multiparticle is usually quicker than that of the single particle. The permeation of particle through a five-helix-bundle shows similar properties as that through a four-helix-bundle.
A design technique to improve the performance of flux-reversal machines
Authors: Kim Tae Heoung , Lee Ju
Published: March 2005

Flux-reversal machine (FRM) is a doubly salient stator permanent magnet (PM) machine with flux linkage reversal in the stator concentrated windings. It can operate in both motoring and generating modes. In this paper, a design technique to improve the performance of FRM is proposed. The proposed techniques have a stator winding and a magnet arrangement method. The stator and rotor shapes of concave-type and a flux barrier are also proposed. According to the experimental results, it is shown that the proposed FRM has improved the performance.
Charge transfer in the Cl−CO cluster induced by core ionization
Authors: Kryzhevoi Nikolai V. , Dobrodey Nickolay V. , Cederbaum Lorenz S.
Published: March 2005

Ab initio calculations of core-ionization spectra of the anion-molecule Cl−CO cluster are performed. Particular attention is paid to the investigation of charge-transfer screening processes accompanying core ionization of the CO molecule in the cluster. The charge-transfer processes are very efficient and favored by the presence of a low-lying unoccupied π* orbital in CO capable of accepting an electron from Cl−. The O1s−1 and C1s−1 core-ionization spectra are calculated and compared. Both reveal a breakdown of the quasiparticle picture of core ionization caused by the charge-transfer processes. Remarkable differences between these two spectra are found which manifest themselves in distinct intensity distributions in the prominent low-energy spectral bands. The underlying reason for these differences is elucidated and linked with the preference of the π* orbital to localize mainly on carbon. Core-ionization spectra of anion-molecule clusters are very sensitive to the type of the molecule involved as the comparative analysis of the O1s−1 core-ionization spectra of the Cl−CO and Cl−H2O clusters show.
Atomic layer deposition of hafnium oxide on germanium substrates
Authors: Delabie Annelies , Puurunen Riikka L. , Brijs Bert , Caymax Matty , Conard Thierry , Onsia Bart , Richard Olivier , Vandervorst Wilfried , Zhao Chao , Heyns Marc M. , Meuris Marc , Viitanen Minna M. , Brongersma Hidde H. , de Ridder Marco , Goncharova Lyudmila V. , Garfunkel Eric , Gustafsson Torgny , Tsai Wilman
Published: March 2005

Germanium combined with high-κ dielectrics has recently been put forth by the semiconductor industry as potential replacement for planar silicon transistors, which are unlikely to accommodate the severe scaling requirements for sub-45-nm generations. Therefore, we have studied the atomic layer deposition (ALD) of HfO2 high-κ dielectric layers on HF-cleaned Ge substrates. In this contribution, we describe the HfO2 growth characteristics, HfO2 bulk properties, and Ge interface. Substrate-enhanced HfO2 growth occurs: the growth per cycle is larger in the first reaction cycles than the steady growth per cycle of 0.04nm. The enhanced growth goes together with island growth, indicating that more than a monolayer coverage of HfO2 is required for a closed film. A closed HfO2 layer is achieved after depositing 4–5HfO2 monolayers, corresponding to about 25 ALD reaction cycles. Cross-sectional transmission electron microscopy images show that HfO2 layers thinner than 3nm are amorphous as deposited, while local epitaxial crystallization has occurred in thicker HfO2 films. Other HfO2 bulk properties are similar for Ge and Si substrates. According to this physical characterization study, HfO2 can be used in Ge-based devices as a gate oxide with physical thickness scaled down to 1.6nm.
Transient interfacial tension and dilatational rheology of diffuse polymer-polymer interfaces
Authors: Peters Gerrit W. M. , Zdravkov Alexander N. , Meijer Han E. H.
Published: March 2005

We demonstrate the influence of molecular weight and molecular weight asymmetry across an interface on the transient behavior of the interfacial tension. The interfacial tension was measured as a function of time for a range of polymer combinations with a broad range of interfacial properties using a pendant/sessile drop apparatus. The results show that neglecting mutual solubility, assumed to be a reasonable approximation in many cases, very often does not sustain. Instead, a diffuse interface layer develops in time with a corresponding transient interfacial tension. Depending on the specific combination of polymers, the transient interfacial tension is found to increase or decrease with time. The results are interpreted in terms of a recently proposed model [Shi et al., Macromolecules 37, 1591 (2004)], giving relative characteristic diffusion time scales in terms of molecular weight, molecular weight distribution, and viscosities. However, the time scales obtained from this theoretical approach do not give a conclusive trend. Using oscillatory dilatational interfacial experiments the viscoelastic behavior of these diffusive interfaces is demonstrated. The time evolution of the interfacial tension and the dilatational elasticity show the same trend as predicted by the theory of diffuse interfaces, supporting the idea that the polymer combinations under consideration indeed form diffuse interfaces. The dilatational elasticity and the dilatational viscosity show a frequency dependency that is described qualitatively by a simple Fickian diffusion model and quantitatively by a Maxwell model. The characteristic diffusion times provided by the latter show that the systems with thick interfaces (tens of microseconds and more) can be considered as slower diffusive systems compared to the systems with thinner interfaces (a few micrometers in thickness and less) can be considered as fast diffusive systems.
Nonadiabatic dynamics in the CH3+HCl→CH4+Cl(PJ2) reaction
Authors: Retail Bertrand , Pearce Julie K. , Murray Craig , Orr-Ewing Andrew J.
Published: March 2005

Nonadiabatic dynamics in the title reaction have been investigated by 2+1 REMPI detection of the Cl(P3∕22) and Cl*(P1∕22) products. Reaction was initiated by photodissociation of CH3I at 266nm within a single expansion of a dilute mixture of CH3I and HCl in argon, giving a mean collision energy of 7800cm−1 in the center-of-mass frame. Significant production of Cl* was observed, with careful checks made to ensure that no additional photochemical or inelastic scattering sources of Cl* perturbed the measurements. The fraction of the total yield of Cl(PJ2) atoms formed in the J=12 level at this collision energy was 0.150±0.024, and must arise from nonadiabatic dynamics because the ground potential energy surface correlates to CH4+Cl(P3∕22) products.
Order-disorder nature of ferroelectric BaTi2O5
Authors: Hushur Anwar , Shigematsu Hirotake , Akishige Yukikuni , Kojima Seiji
Published: March 2005

Ferroelectric single crystals of BaTi2O5 have been studied in detail by Raman and high-resolution micro-Brillouin scattering with a focus on the central component of the relaxation mode over a wide temperature range (20–600°C). A relaxation mode has been clearly observed in these single crystals. The temperature dependences of the relaxation time and integrated intensity of the relaxation mode are well reproduced by the extended semiclassical tunneling model. The ferroelectric phase transition shows, at least near the vicinity of Tc, an order-disorder nature. Our results indicate that the spontaneous polarization mainly resulted from the dynamic disorder of the Ti ions in the octahedra along the polar b axis of BaTi2O5.
Soft-lithography-enabled fabrication of large numerical aperture refractive microlens array in hybrid SiO2–TiO2 sol-gel glass
Authors: Yuan X.-C. , Yu W. X. , He M. , Bu J. , Cheong W. C. , Niu H. B. , Peng X.
Published: March 2005

This paper describes a low-cost soft-lithography method for building large-numerical-aperture microlenses in hybrid sol-gel glass. The fabrication processes comprise three steps, namely fabrication of large numerical aperture microlens array in photoresist as a master, replication of the master in poly-dimethylsiloxane (PDMS) as elastomeric molds and reproduction of the PDMS replica onto the hybrid sol-gel glass as an end structure. Comparing with the direct UV fabrication in the photosensitive sol-gel glass, the proposed method provides a unique advantage in terms of fabrication freedom in shape and thickness of micro-optical elements in the sol-gel glass. This eliminates the difficulties in direct photolithography in sol-gel glass for arbitrary shapes and great thickness due to ever increasing demands.
Ab initio computation of the mean inner Coulomb potential of amorphous carbon structures
Authors: Schowalter M. , Titantah J. T. , Lamoen D. , Kruse P.
Published: March 2005

The mean inner Coulomb potential (MIP) of amorphous carbon structures was computed for slabs with mass densities between ρ=2.0g∕cm3 and ρ=3.5g∕cm3 by the full potential linearized augmented plane-wave (FLAPW) method. The amorphous carbon structures consisting of 64 carbon atoms were generated by a classical metropolis Monte Carlo procedure using the Tersoff potential for carbon. The MIP shows a linear dependence on the mass density. Values of the MIP of the amorphous carbon structures are compared with experimental values and with computed values for the MIP of graphite and diamond.
A Comparative Perspective on Urban Spatial Housing Market Structure: Some More Evidence of Local Sub-markets Based on a Neural Network Classification of Amsterdam
Authors: Kauko Tom
Published: March 2005

When analysing the spatial housing market structure of urban areas, a frequently arising question concerns the relevant criteria for housing market segmentation: is it the transaction price or related to other, socioeconomic, demographic and physical features of the location? In this study, two neural network techniques (SOM, LVQ, Kohonen) are used for identifying sub-markets within Amsterdam, The Netherlands. Because of the inductive nature of the modelling, any theory has to be understood in an open sense: generalising the principles of classification to another context to enable elaboration of institutionally sensitive housing market theory. These findings are therefore compared with earlier findings from another urban housing market-namely, Helsinki, Finland. The comparison shows that, while the price alone is an insufficient criterion for both markets, Amsterdam is more fragmented than Helsinki.
The Continuing 'Wind of Change' in the Balkans: Sources of Housing Inequality in Bulgaria
Authors: Vesselinov Elena
Published: March 2005

The research in this paper explores the institutional changes in the housing system during the period of market transition in Bulgaria, which follow suit with the greater societal transformations. The societal changes are linked theoretically with Polanyi's understanding of the transition from a non-market to a market society. His argument helps in establishing the institutional context of the macroeconomic changes in the past decade. The article then focuses on the changing sources of housing inequality. It is argued that there are two urban regimes of housing inequality: the regime of controlled uniformity during the period of socialism and the regime of primitive diversity during the period of market transition. The two regimes are produced mainly through the changing role of the state.
Social Labour, Employ ability and Social Exclusion: Pre-employment Training for Call Centre Work
Authors: Belt Vicki , Richardson Ranald
Published: March 2005

Recent years have seen the growth of pre-employment training initiatives focusing on developing generic skills amongst the long-term unemployed in an attempt to ensure their access to jobs in the service economy. This article is concerned with the effectiveness of such training, focusing specifically on initiatives designed to equip trainees with the generic skills required for call centre work. Drawing upon data gathered via case study research carried out in the North East of England, the article considers the extent to which the training schemes studied were successful in improving the employability of participants. In doing so, it contributes to current debates about the implications of economic restructuring for the nature of work, skills and labour market disadvantage.
Old Industrial Regions and Employability
Authors: Danson Mike
Published: March 2005

Inactivity has been growing across the developed world and is especially high in old industrial areas. A general move towards more flexible labour markets and the restructuring in these regions over the past quarter of a century have led to a change in the supply and demand conditions for employment. There is an increasing dependence on school and higher education qualifications and associated transferable skills and competencies, while the decline of traditional occupations has left many without jobs and facing multiple barriers to regaining employment. Often lacking demonstrable and accredited human capital and work experience, individuals with such employability problems have been concentrated in particular households and communities-polarising society. Policy interventions are required to address these obstacles and social exclusion, but central government appears reluctant to face the full direct costs of implementation. More radical innovative solutions are now being proposed at the metropolitan level.
Our Experience with Pediatric Epilepsy Surgery Focusing on Corpus Callosotomy and Hemispherotomy
Authors: Shimizu Hiroyuki
Published: March 2005

Summary:  Purpose: In pediatric patients with intractable epilepsy, surgical intervention should be considered in terms of seizure control and prevention of neuronal deterioration. We present our experience with pediatric epilepsy surgery, focusing on corpus callosotomy and hemispherotomy.

Methods: A total of 257 pediatric patients underwent epilepsy surgeries during the last decade in our clinic. The two most common surgical procedures were corpus callosotomy and hemispherotomy. The surgical outcomes of the patients undergoing these operations were analyzed with regard to seizure outcomes and surgical complications.

Results: Corpus callosotomy proved to be extremely effective in controlling drop attacks, especially when the callosum was totally sectioned. Postoperative improvement of psychomotor function also was noticeable in >70% of the cases. In patients who underwent hemispherotomy, the etiology of unilateral hemispheric lesions was closely related to surgical results, with cases of hemimegalencephaly having the worst seizure outcome and most frequent surgical complications. Incomplete section of the callosum, one of the most important causes of residual seizures, was found in three cases.

Conclusions: In pediatric epilepsy surgery, corpus callosotomy is very effective in abolishing drop attacks and improving postoperative psychomotor function. For hemispherotomy, cases of hemimegalencephaly had the worst seizure control and surgical complications. Incomplete section of the corpus callosum should be carefully evaluated as a cause of surgical failure.
Priority of Epilepsy Research in Asia
Authors: Jain Satish
Published: March 2005

Summary:  Epilepsy is the most common serious disorder of the brain, characterized by recurrent unprovoked seizures. It is estimated that there are ∼50 million people with epilepsy worldwide, the majority of which today are living in the developing countries. Many countries in the Asian Oceanian regions have large populations and limited resources. Most such countries do have a vast health‐care network with few centres of excellence that are comparable to the best in the world. The peculiar sociocultural milieu of this region provides a large population with epilepsy that can be used as a unique tool to conduct research into the basic processes, clinical aspects and psychosocial consequences of epilepsy. The Asian Oceanian region offers tremendous opportunities for research despite its limited resources. The clinicians and scientists need to be aware of the basic realities of the region and take full advantage of the situation to work for the benefit of humanity.
Disease‐limited distributions? Contrasts in the prevalence of avian malaria in shorebird species using marine and freshwater habitats
Authors: Mendes Luisa , Piersma Theunis , Lecoq Miguel , Spaans Bernard , E. Ricklefs Robert
Published: March 2005

Migratory shorebirds show strong dichotomies in habitat choice during both the breeding and nonbreeding season. Whereas High Arctic breeding species are restricted to coastal marine and saline habitats during the nonbreeding season, more southerly breeding species tend to use freshwater habitats away from coasts. It has been proposed that this co‐variation in habitat use is a consequence of a single axis of adaptation to pathogens and parasites, which are hypothesized to be relatively scarce in High Arctic, marine, and saline habitats and relatively common at lower latitudes and in freshwater habitats. Here we examine this contrast by comparing the prevalence of avian malaria infections in shorebirds occupying different habitats. We used a PCR‐based assay on 1319 individuals from 31 shorebird species sampled in the Arctic, in temperate Europe and in inland and marine habitats in West Africa. Infections mainly occurred in tropical wetlands, with the shorebirds in freshwater inland habitats having significantly higher prevalence of malaria than birds in marine coastal habitats. Infections were not found in birds migrating through Europe even though conspecifics did show infections in tropical Africa. Adults should resist infection better than juveniles, but showed higher malaria prevalence, suggesting that infection probability increases with cumulative exposure. We argue that exposure to vectors is the main factor explaining the habitat‐related differences in malaria prevalence.
Elephants in space and time
Authors: Cushman Samuel A , Chase Michael , Griffin Curtice
Published: March 2005

Autocorrelation in animal movements can be both a serious nuisance to analysis and a source of valuable information about the scale and patterns of animal behavior, depending on the question and the techniques employed. In this paper we present an approach to analyzing the patterns of autocorrelation in animal movements that provides a detailed picture of seasonal variability in the scale and patterns of movement. We used a combination of moving window Mantel correlograms, surface correlation and crosscorrelation analysis to investigate the scales and patterns of autocorrelation in the movements of three herds of elephants in northern Botswana. Patterns of autocorrelation of elephant movements were long‐range, temporally complicated, seasonally variable, and closely linked with the onset of rainfall events. Specifically, for the three elephant herds monitored there was often significant autocorrelation among locations up to lags of 30 days or more. During many seasonal periods there was no indication of decreasing autocorrelation with increasing time between locations. Over the course of the year, herds showed highly variable and complex patterns of autocorrelation, ranging from random use of temporary home ranges, periodic use of focal areas, and directional migration. Even though the patterns of autocorrelation were variable in time and quite complex, there were highly significant correlations among the autocorrelation patterns of the different herds, indicating that they exhibited similar patterns of movement through the year. These major patterns of autocorrelation seem to be related to patterns of rainfall. The strength of correlation in movement patterns of the different herds decreased markedly at the cessation of major rain events. Also, there was a strong crosscorrelation between strength of autocorrelation of movement and rainfall, peaking at time lags of between three and four weeks. Overall, these approaches provide a powerful way to explore the scales and patterns of autocorrelation of animal movements, and to explicitly link those patterns to temporally variable environmental attributes, such as rainfall or vegetation phenology.
North Atlantic climate variation influences survival in adult fulmars
Authors: Grosbois Vladimir , Thompson Paul M.
Published: March 2005

There is increasing evidence that large scale climate variation influences reproductive parameters of seabirds, but fewer studies have investigated possible effects on adult survival. Previous work has shown that climate variation reflected by the winter North Atlantic oscillation (WNAO) influences reproductive success in northern fulmars. Here, we use a 34 year long (1962–1995) individual‐based data set to investigate inter‐annual and inter‐individual variation in adult survival in this species. Breeding success in the previous and current seasons, and both the WNAO and one‐year lagged WNAO indexes, were considered as potential sources of inter‐annual variation in survival and recapture probabilities. Sex and an index of body size were considered as potential sources of inter‐individual variation in survival and recapture probabilities. Body size effects were not significant, but males and females differed in both their survival and recapture probabilities. Probability of recapture of females was positively correlated with breeding success in both the current and previous breeding seasons, whereas male recapture probabilities were correlated only with previous breeding success. Male and female survival decreased over the study period, suggesting that there had been a degradation of environmental conditions. This hypothesis was supported by the detection of a negative correlation between survival and the WNAO, which, in turn, showed a positive increase over this period. The negative correlation between female adult survival and WNAO did not result only from the long term behaviour of the two time series, but persisted for higher frequency fluctuations. In contrast, the correlation between male survival and WNAO seemed to result only from the long term behaviour of the two time series. Despite uncertainties over causal mechanisms, these findings add to the body of evidence that large scale climate variation could dramatically affect seabird population dynamics. Furthermore our results suggest that climate variation can differentially influence individuals with distinct phenotypic characteristics.
First year demography of the foundation species, Ascophyllum nodosum, and its community implications
Authors: Dudgeon Steve , Petraitis Peter S.
Published: March 2005

Long‐lived species of large size can play critical roles as ecosystem engineers but the demography of early life stages is poorly known for many such species. For example, the fucoid alga, Ascophyllum nodosum, serves as the foundation species for many sheltered rocky shore communities of the North Atlantic Ocean, yet its early demography is incompletely characterized. Here we provide data on age‐specific survivorship throughout the first year. We outplanted zygotes generated from artificial fertilizations and followed their survivorship under different conditions that tested the following hypotheses: (1) survivorship is inversely related to clearing size, (2) germlings survive better in clearings in conspecific stands than in clearings in mussel beds, (3) survivorship in microhabitat refugia (grooves of artificial surfaces) is greater than that on flat surfaces, and (4) protection from grazing and physical factors, like canopy sweeping and desiccation, enhances germling survival. Germlings were censused on days 2, 9, 13, 17, 64, 102, 127 and 399 following outplanting. Germling mortality was consistently higher on flats than in grooves of artificial surfaces, and was greatest within the first two days of life. Germlings protected by cages survived better during the day 0–2 interval, but after 2 days caging did not matter. Interval‐specific mortalities after day 2 showed that survivorship was inversely related to clearing size. The type of clearing, in conspecific stands or mussel beds, did not affect survivorship. Ascophyllum nodosum shows a strong type III survivorship curve with mortality during year 1 exceeding 99.9%. The poor survivorship of first year germlings accounts for the paucity of newly recruited juveniles often observed in mature stands of A. nodosum. The lack of juveniles and the scale dependent survivorship of germlings renders populations of A. nodosum, and the associated community that depends on it, vulnerable to large scale perturbations.
Identification of the immunodominant regions of the Em18 antigen and improved serodiagnostic specificity for alveolar echinococcosis
Authors: Jiang L. , Xu X.‐N. , Li X. , Xue H.‐C. , Feng Z.
Published: March 2005

The aim of this work was to identify the immunodominant regions of the Em18 antigen to improve the specificity in diagnosis of alveolar echinococcosis (AE). Two recombinant antigens ReEm18‐1 and ReEm18‐2, which have the same sequence except that nine amino acid residues are absent in ReEm18‐2, were tested by ELISA and Western Blot (WB) for their diagnostic efficiency. Serological evaluation of the two antigens demonstrated that the sensitivity of both antigens was 95·5% in ELISA and WB, and the specificity was 93·6% and 95·7% in ELISA, and 81·4% and 82·9% in WB, respectively. Five more expression clones (EmS1–EmS5), which contain different regions of the Em18 sequence, were constructed for defining the immunodominant regions of the antigen. Fourteen monoclonal antibodies (mAbs) against ReEm18‐2 antigen and the sera from different groups of patients were used to identify the epitope regions of the five antigen fragments. Results showed that the epitopes recognized by the mAbs are located in the N‐terminal third of the sequence, but the immunodominant area recognized by native serum antibodies may be located further downstream (C‐terminal) in the sequence. The nonspecific cross‐reactivity is due to epitopes present in the C‐terminal third of the sequence. The antigen fragments that contain the first two‐thirds of the sequence have the same sensitivity to AE sera as those of the ReEm18‐1 and ReEm18‐2 antigens, but removal of the C‐terminal third of the sequence improved the specificity of the assay from 93·6% to 99·3% (ELISA) and 81·4% to 90·7% (WB). We conclude that the necessary part of the ReEm18 antigen sequence for AE diagnosis is the N‐terminal half to two‐thirds of the entire sequence.
Echinococcus multilocularis metacestode extract triggers human basophils to release interleukin‐4
Authors: Aumüller E. , Schramm G. , Gronow A. , Brehm K. , Gibbs B. F. , Doenhoff M. J. , Haas H.
Published: March 2005

Infections with parasitic helminths are associated with a T helper 2 (Th2) immune response and IgE production. The underlying mechanism, however, is only partially understood. Recently we have isolated a protein from extracts of Schistosoma mansoni eggs that triggers human basophils from non‐sensitized donors to release interleukin‐4 (IL‐4), the key cytokine of a Th2 response. We called this protein IPSE (for IL‐4‐inducing principle from Schistosoma mansoni eggs). Supposing that IPSE‐like IL‐4‐inducing activities might be a general principle shared among different helminth species, we investigated extracts from the cestode E. multilocularis for its effect on human basophils. Our results showed that extracts from metacestodes of E. multilocularis cause basophil degranulation, as well as the secretion of histamine, IL‐4 and IL‐13, in a dose‐dependent manner. IgE stripping and resensitization of basophils indicated that the mechanism of IL‐4 induction requires the presence of IgE on the cells. Since analogous properties have been demonstrated earlier for IPSE, we think that S. mansoni and E. multilocularis may induce a Th2 response in their hosts via a related mechanism, namely, by the induction of IL‐4 release from basophils.
Micro‐geographical variation among male populations of the sandfly,Lutzomyia(Nyssomyia)intermedia, from an endemic area of American cutaneous leishmaniasis in the state of Rio de Janeiro, Brazil
Authors: Meneses C. R. V. , Cupolillo E. , Monteiro F. , Rangel E. F.
Published: March 2005

Abstract. The genetic relationships among maleLutzomyia(Nyssomyia)intermedia(Lutz & Neiva) (Diptera: Psychodidae) from three populations from the same endemic area of American cutaneous leishmaniasis (ACL) in the state of Rio de Janeiro, Brazil, were compared. The sandflies were collected in three ecologically different habitats: domestic, extra‐domestic and sylvatic over a total range of 800 m. Three molecular markers were employed to assess population variation. Based on MLEE markers, it could not be concluded that the three populations do not belong to the same gene pool (Fst = 0.005). No within‐population departure from Hardy–Weinberg equilibrium was detected (P < 0.05) and they presented the same level of gene variation. The number of migrants (Nm) indicated that at least 50 individuals per generation migrated between the three habitats. RAPD‐PCR markers revealed that, except for the primer five, all were polymorphic. Phenetic analysis of the genotypes showed the presence of two principal clusters corresponding to: (1) domestic plus extra‐domestic and (2) sylvatic. Unique genotypes were observed in each population. The sylvatic population was the most polymorphic, showing the largest number of genotypes and low level of similarity between them. Three mtDNA gene markers were studied by SSCP analysis. The most frequent haplotype for each marker ranged in frequency from 60 to 87% and individuals with unique haplotypes varied from 1 to 5%. Interestingly, the SSCP analysis showed a low level of polymorphism within populations. The disagreement between the different molecular markers observed and the hypothesis thatL. intermediacould be participating in the transmission cycle ofLeishmania(Viannia)braziliensisin environments ranging from the interior of human dwellings to the forest, are discussed.
A double‐blinded, placebo‐controlled trial of garlic as a mosquito repellant: a preliminary study
Authors: Rajan T. V. , Hein M. , Porte P. , Wikel S.
Published: March 2005

Abstract.  The hypothesis that the ingestion of garlic provides protection against bloodsucking pests such as mosquitoes was investigated using a randomized, double‐blinded, placebo‐controlled crossover study. Subjects were asked to consume either garlic (one visit) or a placebo (the other visit). They were then exposed to laboratory‐reared Aedes aegypti (Linnaeus) (Diptera: Culicidae). The numbers of mosquitoes that did not feed on the subjects, the number of mosquito bites, the weights of the mosquitoes after feeding and the amounts of blood ingested were determined. The data did not provide evidence of significant systemic mosquito repellence. A limitation of the study is that more prolonged ingestion of garlic may be needed to accomplish repellence.