bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectroscopic and quantum‐control aspects of ultrashort‐pulse synthesis through impulsive high‐order stimulated Raman scattering
Authors: Zheltikov A. M. 
Published: January 2005

AbstractThe spectroscopic and quantum‐control aspects of short‐pulse synthesis through the generation of multiple Stokes and anti‐Stokes sidebands in an impulsively pre‐excited Raman‐active medium are considered. The use of sequences of short laser pulses leading to a resonant excitation of Raman modes is shown to allow the generation of multiple Stokes and anti‐Stokes sidebands to be considerably enhanced, with the characteristic length of the spectral broadening of a probe pulse propagating in a Raman‐active medium pre‐excited by a sequence of short pulses being inversely proportional to the number of pulses in this sequence. Coherent four‐wave mixing techniques are shown to be a convenient tool for visualizing the result of impulsive preparation of a Raman‐active medium. The results of Raman spectroscopic studies are used to specify Raman‐active molecules with sufficiently short periods of Raman vibrations and high efficiencies of Raman scattering, which offer especially much promise for the generation of few‐cycle light pulses in Raman‐active media. Copyright © 2002 John Wiley & Sons, Ltd.
Micro‐Raman scattering in Nb2O5–TiO2 ceramics
Authors: Dobal P. S. , Dixit A. , Katiyar R. S. , Choosuwan H. , Guo R. , Bhalla A. S. 
Published: January 2005

AbstractSingle‐phase (Nb2O5)1−x(TiO2)x ceramics were prepared for x = 0.00, 0.05, 0.08 and 0.11 compositions using a solid‐state reaction technique. The effect of TiO2 substitution on the vibrational and phase transition behavior of Nb2O5 was studied using the micro‐Raman scattering technique and compared with similar results on Ta2O5. The external modes resulting from interaction among various polyhedra were observed and vibrational changes were studied in the temperature range −200 to 1100°C. An increase in structural disorder was reflected in the Raman spectra with increasing TiO2 content in both Nb2O5 and Ta2O5. Ta2O5 shows a phase transition at about 300°C . However, a low‐temperature phase transition was observed about 50°C from (Nb2O5)1−x(TiO2)x compositions. Copyright © 2002 John Wiley & Sons, Ltd.
Polarized infrared and Raman spectra of KGd(WO4)2 and their interpretation based on normal coordinate analysis
Authors: Macalik L. , Hanuza J. , Kaminskii A. A. 
Published: January 2005

AbstractThe direction of the transition dipole moments for the vibrations of the single WOW and double WOOW oxygen bridges in layered scheelite tungstates is derived from the Polarized infrared and Raman spectra of the KGd(WO4)2 single crystal. Their experimental values are compared with those obtained from the calculated atomic Cartesian displacements for the particular normal modes. The assignment of the IR and Raman bands to the respective molecular vibrations was obtained on the basis of the normal coordinate analysis and potential energy distribution. Copyright © 2002 John Wiley & Sons, Ltd.
Raman spectra and thermal transformations of ferrihydrite and schwertmannite
Authors: Mazzetti L. , Thistlethwaite P. J. 
Published: January 2005

AbstractRaman and infrared spectra of 2‐line and 6‐line ferrihydrite and schwertmannite were recorded. The spectra of the ferrihydrites are compatible with octahedrally coordinated Fe3+. The spectra of schwertmannite are consistent with Fe(O,OH)6 octahedra in some of which an OH− ion has been replaced by a SO42− ion which acts as a bridging bidentate ligand to two Fe3+ ions. The Raman spectra show that under heating by the He–Ne laser beam 2‐line ferrihydrite and schwertmannite transform to hematite via a maghemite intermediate, whereas 6‐line ferrihydrite transforms directly to hematite. The different thermal transformation behaviour of the two ferrihydrites accords with recent reports that the two forms are structurally different and suggests that it is the disordered component of 2‐line ferrihydrite that transforms to maghemite on heating. In the case of schwertmannite the loss on heating of SO42− ions in the form of SO3 and H2O entails the simultaneous loss of OH− ions and the conversion of some OH− ions to O2−. The loss and resulting rearrangement of ligands around those Fe3+ ions originally liganded by SO42− results in a fraction of Fe3+ achieving the tetrahedral coordination that is associated with maghemite. Copyright © 2002 John Wiley & Sons, Ltd.
Raman characterization of Ar+ ion‐implanted GaN
Authors: Boudart B. , Guhel Y. , Pesant J. C. , Dhamelincourt P. , Poisson M. A. 
Published: January 2005

AbstractAr+ ions were implanted at room temperature in n‐type hexagonal GaN for device isolation purpose. We performed electrical measurements and resonance Raman spectroscopy in order to monitor the electrical and structural changes of non‐annealed and annealed implanted GaN samples. On increasing the implantation dose from 3.4 × 1012 to 3.4 × 1014 ions cm−2, an increase in the electrical isolation and a decrease in the photoluminescence were observed. For a 1016 ions cm−2 dose, the implanted layer became conductive owing to a hopping mechanism and only the first‐order phonon lines remained observable. After annealing at 900 °C for 30 s, the implanted samples became conductive and the photoluminescence reappeared or increased compared with the non‐annealed samples at same implantation doses, except for the sample implanted at the highest dose, which became insulating. Copyright © 2002 John Wiley & Sons, Ltd.
The role of Government in the development of tourism in Kenya
Authors: Akama John S. 
Published: January 2005

AbstractThis study uses the case study of Kenya to analyse the role of government in the development of tourism in the Third World. Usually, government involvement in the development of tourism reflects on the uniqueness and peculiarity of the tourism industry. By its nature, the development and provision of tourism product involves diverse stakeholders and activities. In the diverse socio‐economic situation, it is usually the government that has the required social and political capacity and legitimacy to bring together and co‐ordinate the activities of diverse and different interest groups which are involved in the development of tourism and, also, establish the required level playing field. In this regard, as probably is the case in most less developed countries where tourism is a major socio‐economic activity, the Kenya Government has, over the years, played a crucial role in the development of the country's tourism industry. Particularly, during the exploratory stage of tourism development in Kenya, it was government involvement that helped lay the required groundwork and, as a consequence, jump‐started the rapid development of the country's tourism industry. However, in recent years, particularly in the 1990s, Kenya's tourism industry is confronted with serious problems including declining international visitor arrivals and decreasing tourism revenues. Ironically, the same government that played a crucial role, especially in the initial development of the country's tourism industry, is currently being blamed as being responsible for the industry's current poor performance. Thus, this study will also examine the underlying factors responsible for the current downturns in Kenya's tourism industry and how they relate to the role of government in the development of tourism. Copyright © 2002 John Wiley & Sons, Ltd.
Towards a classification of cultural tourists
Authors: McKercher Bob 
Published: January 2005

AbstractThis paper proposes a model to segment the cultural tourism market according to two dimensions: (i) the importance of cultural motives in the decision to visit a destination and (ii) depth of experience. The model is tested empirically using Hong Kong as a case study. The test identified five discrete cultural tourism market segments that exhibited substantially different behaviour. Copyright © 2002 John Wiley & Sons, Ltd.
Modes of e‐business innovation and structural disruptions in firm knowledge
Authors: Tiwana Amrit 
Published: January 2005

AbstractThis paper explores the linkages between knowledge integration strategy and the modes of innovation in architecturally destructive e‐business settings. Knowledge management (KM) is linked to the concepts of component and architectural knowledge in complex, global e‐business networks. Understanding the structural impact of incremental, radical, architectural, and modular innovations at the business model‐ and systems‐level on knowledge configurations can better guide KM strategy formulation. By delineating these linkages, this paper concludes with implications for managers of globalized teams and highlights open areas for future research. Copyright © 2002 John Wiley & Sons, Ltd.
Sustainability of livestock farming in the communal lands of Southern Namibia
Authors: Kuiper S. M. , Meadows M. E. 
Published: January 2005

AbstractThe impacts of livestock farming in southern Namibia's communal areas are investigated. Small stock farming is ubiquitous in this semiarid region, and provides many people with their only source of wealth and income. It is traditionally thought that livestock grazing negatively impacts on the vegetation resource. Using both interviews and interpretation of sequential aerial photographs, veld (a South African word descriptive of the general vegetation and soils within an area) resilience and changes in vegetation composition and cover were analysed. Results provide contrasting evidence. Resilience is illustrated by good plant regeneration after the 1999–2000 rainy season, an observation that provides support for a disequilibrium interpretation of the landscape, suggesting that productivity here is primarily event driven and not unduly impacted by grazing pressure. Additional, contradictory, results show that vegetation composition has indeed changed in the communal lands, from predominantly palatable perennials to unpalatable annuals. Localized areas of degradation are also evident. Using sequential aerial photography, comparison of land units under commercial tenure (1970) with the situation subsequent to incorporation into Namaland (1998) indicates an increase in bare soil from 6.3 to 11 per cent over the time period in question. This increase is attributed to, among other factors, increased pressure form livestock grazing. Although separating anthropogenic factors from other biophysical ones is difficult, it is argued that appropriate management practices should be employed that take into account both the veld's resilience and the observed localized degradation and species composition changes. Copyright © 2002 John Wiley & Sons, Ltd.
Carbon sequestration in dryland ecosystems of West Asia and North Africa
Authors: Lal R. 
Published: January 2005

AbstractThe West Asia–North Africa (WANA) region has a land area of 1.7 billion ha, and a population of 600 million. Desertification and soil degradation are severe problems in the region. The problem of drought stress is exacerbated by low and erratic rainfall and soils of limited available water holding capacity and soil organic carbon (SOC) content of less than 0.5 per cent. The SOC pool of most soils has been depleted by soil degradation and widespread use of subsistence and exploitative farming systems. The historic loss of a SOC pool for the soils of the WANA region may be 6–12 Pg compared with the global loss of 66–90 Pg. Assuming that 60 per cent of the historic loss can be resequestered, the total soil‐C sink capacity of the WANA region may be 3–7 Pg. This potential may be realized through adoption of measures to control desertification, restore degraded soils and ecosystems, and improve soil and crop management techniques that can enhance the SOC pool and improve soil quality. The strategies of soil‐C sequestration include integrated nutrient management (INM) and recycling, controlled grazing, and growing improved fodder species on rangeland. Improved technologies for cropland include use of INM and biofertilizers, appropriate tillage methods and residue management techniques, crop rotations and cover crops, and water and nutrient recycling technologies. Through adoption of such measures, the potential of soil‐C sequestration in the WANA region is 0.2–0.4 Pg C yr−1. Copyright © 2002 John Wiley & Sons, Ltd.
Rehabilitation of desurfaced soils by afforestation in La Plata County, Argentina
Authors: Giménez J. E. , Salerno M. I. , Hurtado M. A. 
Published: January 2005

AbstractRemoval of topsoil, mainly for making bricks, is one of the main causes of soil loss around large urban centres of the Humid Pampa, Argentina. In about 7 per cent of La Plata County, the 20–40 cm thick A‐horizon has been removed for that purpose. Most of the affected areas were originally prime farmland; however, with removal of the A‐horizon they became unsuitable for agriculture, including grazing, since the exposed Bt‐horizon is unsuited for plant growth due to its high clay content (45–65 per cent) and the low nutrient levels. Since trees survive better on poor soils than do agricultural crops, the possibility of afforestating desurfaced soils has been studied. Eucalyptus are one of the major species used in tree planting programmes aimed at reclaiming degraded soils since they are fast growing and can grow to commercial size in a wide range of soils and climatic conditions. The work reported here was done in a desurfaced Vertic Argiudoll and a similar non‐desurfaced soil (control). Three Eucalyptus species were tested, i.e. E. camaldulensis, E. viminalis and E. dunnii. Their height and diameter (dbh) growth were 47.9 to 75.8 per cent less and timber volume 86.5 to 98.5 per cent less on the desurfaced soil. E. camaldulensis grew best in all the parameters in the desurfaced soil. Although tree growth was poor, afforestation may be an alternative use for desurfaced soils where agriculture and livestock breeding are not possible. Copyright © 2002 John Wiley & Sons, Ltd.
Floodwater use and management strategies in valleys of southeast Spain
Authors: Hooke J. M. , Mant J. 
Published: January 2005

AbstractSoutheast Spain has a semiarid climate with highly variable rainfall from year to year. Global warming scenarios predict a decrease in rainfall in future and land‐use changes may also alter run‐off regimes. Water deficit has meant that various practices of floodwater farming have traditionally operated in valley floors. However, flash floods in the valley floors can also be dangerous and damaging. Many of the boqueras and other floodwater irrigation systems have been abandoned. The effects on the hydrological regime of the channel are calculated. These structures and water management practices could have an effect on the magnitude of low–moderate peak discharges, but are insignificant in high flows. Modern channel and flood management employs check dams, but these are frequently destroyed in moderate–high flows. Alternative strategies of channel management need to be sought and the use of vegetation cover to dissipate flood peaks and to reduce erosion may offer one possibility. Copyright © 2002 John Wiley & Sons, Ltd.
Determination of chemical agent optical clearing potential using in vitro human skin
Authors: Choi Bernard , Tsu Laura , Chen Eric , Ishak Teresa S. , Iskandar Sarah M. , Chess Samuel , Nelson J. Stuart 
Published: January 2005

AbstractBackground and Objectives:Optical clearing is a method that temporarily reduces the optical scattering of biological tissues.Study Design/Materials and Methods:To determine the optical clearing potential (OCP) of various chemical agents, we examined the change in reduced scattering coefficients of in vitro human skin after application directly to the dermal side.Results/Conclusions:We found that the mean agent OCP did not correlate with refractive index or osmolality. Lipophilic hyperosmotic agents had a mean OCP less than unity, indicating increased optical scattering. © 2005 Wiley‐Liss, Inc.
A Combination of Selective Light Reflection and Fluorescence Modulation in a Cholesteric Polymer Matrix
Authors: Medvedeva Dasha , Bobrovsky Alexey , Boiko Natalia , Shibaev Valery , Zavarzin Igor , Kalik Marina , Krayushkin Mikhail 
Published: January 2005

AbstractSummary: The phase behavior and optical properties of a cholesteric ternary copolymer, containing nematogenic phenylbenzoate, cholesteric, and photochromic diarylethene side groups, and its mixture with 2 wt.‐% fluorescent dopant were studied. The investigation of the kinetics of a photochemical opening‐cycle process of the photochromic groups in the cholesteric mixture proved the energy transfer from the fluorescent dopant to the photochromic diarylethene groups. It was shown that the fluorescence intensity of the fluorescent dopant could be controlled by the portion of the “closed” form of the diarylethene groups. During the photocyclization of the photochromic groups a “degeneration” of the selective light reflection of the cholesteric matrix is observed.Fluorescence‐resonance energy transfer makes possible the process of photosensitization of the back ring‐opening photoreaction of the photochromic diarylethene groups in the cholesteric polymer matrix.imageFluorescence‐resonance energy transfer makes possible the process of photosensitization of the back ring‐opening photoreaction of the photochromic diarylethene groups in the cholesteric polymer matrix.
60th Birthday of Prof. Dr. Dr. h.c. Heino Finkelmann
Authors: Mülhaupt Rolf 
Published: January 2005

AbstractThis section contains news of the macromolecular community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de. The editorial office decides which articles will be published.
Dynamic decision problem structuring
Authors: Corner James , Buchanan John , Henig Mordecai 
Published: January 2005

AbstractThis paper develops a conceptualization of decision problem structuring which synthesizes a number of models and approaches cited in the decision‐making literature in general and the multi‐criteria literature in particular. The approach advocates a dynamic interaction between criteria and alternatives as a decision‐maker understands his preferences and expands the set of alternatives. This approach endeavours to bridge the gap between prescriptive and descriptive decision problem structuring. It is prescriptive in its orientation, recommending an approach based on earlier prescriptive work. However, the approach is also validated empirically, based on the descriptive decision‐making literature and reported case studies of actual decision‐making. Copyright © 2001 John Wiley & Sons, Ltd.
Relative performance as a strategic commitment mechanism
Authors: Miller Nolan , Pazgal Amit 
Published: January 2005

AbstractCan managers' personality traits be of use to profit maximizing firm owners? We investigate the case where managers have a variety of attitudes toward relative performance that are indexed by their type. We consider two stage games where profit maximizing owners select managers in the first stage, and these managers, knowing each other's types, compete in a duopoly game in the second stage. The equilibria of various types of competition are derived and comparisons are made to the standard case where managers are profit maximizers. We show that managers' types can be used as a strategic commitment device that can increase firm profits in certain environments. Copyright © 2002 John Wiley & Sons, Ltd.
Strategic behavior in a service industry
Authors: Ilmakunnas Pekka 
Published: January 2005

AbstractA model of service duopoly is formulated, where the arrival of customers and their service time in the firm are stochastic. The firms first choose the service capacity, and given the capacity they then choose the price in a Bertrand competition. Capacity choices have a negative externality on the competitor, since increased capacity in one firm decreases its expected full price (price plus cost of waiting) and leads to a flow of customers from the other firm. If the firms choose capacities strategically, it is optimal to underinvest compared to the non‐strategic case, but this result may arise in different ways. By underinvesting the firms commit themselves to longer queues (lower quality) to relax price competition. Copyright © 2002 John Wiley & Sons, Ltd.
Lancaster's characteristics approach revisited: product selection using non‐parametric methods
Authors: Fernandez‐Castro Angel S. , Smith Peter C. 
Published: January 2005

AbstractIn consumer theory, the principles of Lancaster's characteristics approach and hedonic pricing appear to offer the most promising insight into choice when qualitative aspects are important. The paper reconciles these principles with the family of non‐parametric frontier estimation methods known as data envelopment analysis. It is shown that, with some straightforward adjustments, DEA is entirely consistent with the characteristics view of consumer choice found in the economics literature. In making Lancaster's ideas operational, the paper also addresses the theoretical concern voiced by Lancaster about combining indivisible products. The principles are illustrated with a case study involving the comparison of diesel cars. The paper concludes that the user will ultimately have to apply some judgement in choosing between competing efficient products. However, the analysis should help to restrict the number of products to be assessed to manageable proportions. Copyright © 2002 John Wiley & Sons, Ltd.
Homogenization of the linearized system of elasticity in anisotropic heterogeneous thin cylinders
Authors: Sili Ali 
Published: January 2005

AbstractThis paper is the second of the two announced in our Note (Sili A, [16]). It generalizes to the linearized system of elasticity the results of our previous work (Sili, 2000 [15]) on the heat equation. We study the asymptotic analysis, as ϵ tends to zero, of the solution uϵ of the linearized system of elasticity posed on a composite elastic cylindrical domain Ωϵ with radius ϵ and height L. The heterogeneities of the material are assumed to be periodic with a period ϵ along the cylinder axis and with a period ϵ2 along the sections of the cylinder. It is shown that the limit problem is a system in which appear two entities: the first one (u, v, w) corresponds to the reduction of dimension 3d–1d while the second one (û, v̂, ŵ) takes into account the homogenization process. Moreover, a corrector result is given. Copyright © 2002 John Wiley & Sons, Ltd.
On a boundary variational inequality of the second kind modelling a friction problem
Authors: Guediri Hocine 
Published: January 2005

AbstractA scalar contact problem with friction governed by the Yukawa equation is reduced to a boundary variational inequality. The presence of the non‐differentiable friction functional causes some difficulties when approximated. We present two methods to overcome this difficulty. The first one is a regularization leading to a non‐linear boundary variational equation, for which we propose an iterative procedure, whereas the second method is based on the boundary mixed variational formulation involving Lagrange multipliers. We propose Uzawa's algorithm to compute the saddle point of the corresponding boundary Lagrangian and investigate the discretization of various formulations by the boundary element Galerkin method. Convergence of the boundary element solution is proved and a convergence order is obtained. Copyright © 2002 John Wiley & Sons, Ltd.