bluuebunny/crossref_metadata_2025 huggingface dataset:
Methane dissociation on Ni(111): The effects of lattice motion and relaxation on reactivity
Authors: Nave Sven , Jackson Bret
Published: December 2007

The effects of lattice motion and relaxation on the dissociative adsorption of methane on a Ni(111) surface are explored. Electronic structure methods based on the density functional theory are used to compute the potential energy surface for this reaction. It is found that, in the transition state and product regions, there are forces causing the Ni atom over which the molecule dissociates to move out of the surface. In order to examine the extent to which the lattice might pucker during this reaction, high dimensional fully quantum scattering calculations are carried out. It is found that a significant amount of lattice puckering can occur, even at large collision energies, lowering the barrier to reaction and increasing the dissociative sticking probability. This is shown to be in contrast to the predictions of the surface oscillator model. While we observe similar puckering forces for this reaction on Pt(111), our calculations suggest that the puckering on this surface will be considerably less due to the larger metal atom mass. The “laser off” reactivities of CD3H on Ni(111) are computed, and it is demonstrated that there can be significant contributions to the reactivity from vibrationally excited molecules, particularly at lower collision energies, or when a large nozzle temperature is required to attain the necessary collision energy for reaction. Comparisons are made with recent experiments with regard to the variation of reactivity with collision energy, vibrational state, and surface temperature.
Effect of ferromagnetic properties in Al-doped Zn1−xCoxO nanowires synthesized by water-assistance reactive vapor deposition
Authors: Liao L. , Lu H. B. , Zhang L. , Shuai M. , Li J. C. , Liu C. , Fu D. J. , Ren F.
Published: December 2007

The Zn1−xCoxO and Al-doped Zn1−xCoxO nanowires have been synthesized by the water-assistance reactive vapor deposition method. No Co precipitates appeared in the both kinds of ZnO nanowires according to the results observed by high-resolution transmission electron microscope, x-ray diffraction, and electron energy-loss spectroscopy, revealing that the magnetism of the ZnO nanowires was independent of the Co precipitates. The Al-doped Zn1−xCoxO nanowires show much stronger ferromagnetism than Zn1−xCoxO nanowires in the temperature range of 4–350 K. It is believed that the ferromagnetism in Zn1−xCoxO nanowires could be enhanced by Al doping to introduce donor carriers. Moreover, a multiple mechanism for the ferromagnetism of Al-doped Zn1−xCoxO nanowires is discussed.
Consideration of the relationship between Kepler and cyclotron dynamics leading to prediction of a nonmagnetohydrodynamic gravity-driven Hamiltonian dynamo
Authors: Bellan P. M.
Published: December 2007

Conservation of canonical angular momentum shows that charged particles are typically constrained to stay within a poloidal Larmor radius of a poloidal magnetic flux surface. However, more detailed consideration shows that particles with a critical charge-to-mass ratio can have zero canonical angular momentum and thus can be both immune from centrifugal force and not constrained to stay in the vicinity of a specific flux surface. Suitably charged dust grains can have zero canonical angular momentum and in the presence of a gravitational field will spiral inwards across poloidal magnetic surfaces toward the central object and accumulate. This accumulation results in a gravitationally-driven dynamo, i.e., a mechanism for converting gravitational potential energy into a batterylike electric power source.
A TE21 second-harmonic gyrotron backward-wave oscillator with slotted structure
Authors: Chen N. C. , Yu C. F. , Chang T. H.
Published: December 2007

Second-harmonic gyrotron backward-wave oscillator (gyro-BWO) with a reduced magnetic field strength is a tunable source in the millimeter wave regime, but it has long been impeded by the severe mode competition as a result of low efficiency and narrow bandwidth. This study employs a slotted structure functioning as a mode selective circuit to suppress the lower order transverse modes. In addition, a two-step tapered waveguide is adopted to stabilize the higher-order transverse modes and axial modes. Some important characteristics of the slotted gyro-BWO will be analyzed and discussed. As a calculated result, the interaction efficiency is improved and the stable tuning range is broadened. A stable, Ka-band, slotted second-harmonic gyro-BWO is capable of producing an efficiency of 23% with a 3dB tuning bandwidth of 9% at 5A and 100kV.
Origin of the open circuit voltage of donor-acceptor solar cells: Do polaronic energy levels play a role?
Authors: Cravino Antonio
Published: December 2007

This letter analyzes the influence of the energy of the highest-energy occupied molecular orbital (HOMO) and the single occupied molecular orbital (SOMO) (i.e., the low-energy polaronic level) of different electron donors (D) on the open circuit voltage (VOC) value delivered by bilayer and bulk-heterojunction solar cells containing fullerenes as acceptor (A). The analysis further confirms that the VOC of these devices scales with the energy difference between the HOMO of the D and the lowest-energy unoccupied molecular orbital of the A. As observed, a better relationship is obtained if the SOMO energy of the D—extracted from photoinduced absorption spectra—is considered.
Metal induced hydrogen effusion from amorphous silicon
Authors: Ohmi Hiromasa , Yasutake Kiyoshi , Hamaoka Yoshinori , Kakiuchi Hiroaki
Published: December 2007

Hydrogen effusion from hydrogenated amorphous silicon (a-Si:H) films, induced by various metal layers (Al, Ni, Cu, Ge, Cr, Au, Ag, Fe, and Sn), has been studied by temperature programed desorption spectroscopy. Significant reduction of the effusion temperature is observed in the presence of Cr, Ni, or Al on the a-Si:H film. Al has the strongest catalytic effect on hydrogen effusion from a-Si:H; H2 effusion is intensive, even at a temperature of 150°C, when the Al layer thickness is larger than 40nm. The strong catalytic effect of Al is considered to be related to the large diffusion constant of Al in a-Si:H.
Dynamics of small dust clouds trapped in a magnetized anodic plasma
Authors: Pilch Iris , Piel Alexander , Trottenberg Thomas , Koepke Mark E.
Published: December 2007

Small dust clouds, which are confined in an anodic plasma, are studied with respect to their structure and their response to modulation of the anode bias. The dust cloud is displaced from the center of the discharge by a process similar to the void mechanism in radio-frequency discharges under microgravity. The top layers of the dust cloud are in a crystalline state and the cloud performs a slow rotation about the magnetic field direction. For modulation frequencies below 15Hz, a sloshing and stretching motion in the confining potential well is found. Spontaneously excited dust density waves are observed when the dust cloud exceeds a minimum size. The waves are characterized by sickle-shaped wave fronts. No standing waves were found. The wave dispersion shows an influence of the boundedness of the system in terms of a frequency cutoff.
Glass tube of high dielectric constant and low dielectric loss for external electrode fluorescent lamps
Authors: Cho Guangsup , Shin Myeong-Ju , Jeong Jong-Mun , Kim Jung-Hyun , Hong Byoung-Hee , Koo Je-Huan , Kim YunKi , Choi Eun-Ha , Fechner Joerg , Letz Martin , Ott Franz
Published: December 2007

A glass tube of aluminosilicate glass, with high dielectric constant K∼6.0 and low dielectric loss tan δ∼8.0×10−4, was investigated for the external electrode fluorescent lamps (EEFLs) of a dielectric barrier discharge. Compared with conventional EEFLs made out of borosilicate glass tubes with K∼(4.9−5.3) and tan δ∼(2.3−2.4)×10−3, the efficiency of the aluminosilicate EEFL increases by 15%−25% even at high luminance above 20 000 cd/m2 and the pinhole stability of the aluminosilicate EEFL also improves remarkably. In a soda-lime glass EEFL with a high dielectric loss tan δ∼7.0×10−3, the luminance and pinhole stability deteriorate even with a high dielectric constant K∼7.2 at room temperature, because the value of tan δ escalates as the temperature on the external electrode increases due to the dielectric heat dissipation.
Enhancement of Seebeck coefficient for SrO(SrTiO3)2 by Sm substitution: Crystal symmetry restoration of distorted TiO6 octahedra
Authors: Wang Yifeng , Lee Kyu Hyoung , Hyuga Hideki , Kita Hideki , Inaba Katsuhiko , Ohta Hiromichi , Koumoto Kunihito
Published: December 2007

We found that Sm3+ substitution in SrO(SrTiO3)2 is effective in improving the Seebeck coefficient (S). The ∣S∣ value increases notably with temperature, benefiting from an enhancement of the density of states (DOS) effective mass md* from ∼3m0 (300K)to∼7.5m0 (1000K), due to an improvement of the local symmetry of TiO6 octahedra, enhancing the degeneracy in the Ti 3d orbitals, which form the conduction band (CB), and also to an accompanying lattice expansion, which gives rise to a higher DOS at the bottom of the CB and, consequently, a larger md*.
Spectroscopic studies on manganese thiophosphate intercalated with cesium ions
Authors: Silipigni L. , Acacia N. , Quattrone T. , De Luca G. , Monsù Scolaro L. , Salvato G.
Published: December 2007

Cesium ions have been intercalated by ion exchange into layered manganese thiophosphate to produce Cs2xMn1−xPS3. Investigations have been conducted by x-ray diffraction analysis, IR absorption spectroscopy, x-ray photoemission spectroscopy (XPS), and dielectric spectroscopy. The XPS spectra, recorded at room temperature and at the Mn, P, and S 2p, Mn 3p, and Cs 3d and 4d core-level regions, indicate that no charge transfer occurs from guest species (Cs+) to pure host lattice (MnPS3). The presence of shake-up satellites at the Mn 2p and 3p core levels suggests that the cesium intercalation does not alter the nature of the Mn–S bond which is mostly ionic. Dielectric measurements, carried out between 260 and 375K and in the 20Hz–1MHz frequency range, classify Cs2xMn1−xPS3 as hopping charge carrier systems. The nature of such carriers can be hypothesized on the basis of both the intercalation process by cationic substitution and the comparison with the observed dielectric response of the pure MnPS3.
A method for applying a large persistent in-plane biaxial stress to influence the perpendicular magnetic anisotropy of magnetic thin films
Authors: Hamann Jorge Enrique , Mohanan Senthilnathan , Herr Ulrich
Published: December 2007

We describe a method of applying large persistent biaxial in-plane tensile stress to thin films by loading a Ta substrate with hydrogen. Using this technique, we studied the influence of biaxial stress on the effective perpendicular magnetic anisotropy (Keff) of Ni and Co50Fe50 thin films. The Keff of Ni increases by 40% whereas for Co50Fe50 it decreases by 15% with respect to that of zero stress state upon applying biaxial stresses of 1.24 and 1.79GPa, respectively. The results are analyzed using a simple model including shape and magnetoelastic anisotropy contributions. The influence of the saturation magnetization and the mechanical properties of the thin films on the maximum achievable relative change of Keff is discussed.
Calorimetric detection of the conical terahertz radiation from femtosecond laser filaments in air
Authors: Houard Aurélien , Liu Yi , Mysyrowicz André , Leriche Bernadette
Published: December 2007

The spectral distribution of the conical terahertz emission from a femtosecond laser filament in air is measured with a bolometric detector and a set of filters, confirming that the main part of the emission lies between 0.5 and 3THz. The efficiency of this terahertz emission is compared with that obtained in air via four wave mixing of femtosecond laser pulses at ω and 2ω in the presence of a plasma.
Microstructure and squareness factor: A quantitative correlation in (Nd, Pr)FeB sintered magnets
Authors: Périgo E. A. , Takiishi H. , Motta C. C. , Faria R. N.
Published: December 2007

A quantitative correlation between the microstructure and squareness factor of R16Fe76B8 (R=Nd or Pr) sintered magnets is proposed. The expression was derived based on the micrographs of 19 magnets, making a total of more than 11 000 grains analyzed. This expression is independent of the determination of the sample’s magnetic properties. Magnet processing conditions were used to modify the microstructure and, hence, the squareness factor. Six microstructural parameters—grain size, grain elongation, grain roundness, and their respective standard deviations—were quantified using an image analyzer software program. The squareness factor was higher for magnets with a microstructure showing rounder grains and a sharp size distribution. A comparison of the squareness factor obtained by the proposed expression with that calculated from the demagnetization curve showed a fairly good agreement. Some disparities were also found and are discussed herein.
Evidence for capping-layer effects on the morphology and plasmon excitation of Ag nanoparticles
Authors: Lantiat D. , Babonneau D. , Camelio S. , Pailloux F. , Denanot M.-F.
Published: December 2007

The structure and optical response of Ag nanoparticles capped with dielectric BN, Al2O3, and Y2O3 layers have been studied. The morphological evolution of the nanoparticles has been investigated in detail by high-angle annular dark-field (HAADF) imaging in a scanning transmission electron microscope and by optical transmittance measurements and simulations of surface-plasmon resonances. We show that the quantitative analysis of plane-view HAADF images enables the average morphology of individual embedded nanoparticles to be revealed. It thus provides a simple method to investigate capping-layer effects, which are demonstrated to be characterized by a substantial reduction of the aspect ratio of the nanoparticles and have been evidenced to strongly depend on the nature of the cap as well as on the size of the nanoparticles. These results suggest that both the morphological and optical properties of noble metal nanoparticles can be tuned by using capping-layer effects and by choosing capping materials with appropriate physicochemical and electronic properties.
Investigation of stress-induced (100) platelet formation and surface exfoliation in plasma hydrogenated Si
Authors: Di Zengfeng , Wang Yongqiang , Nastasi Michael , Rossi Francois , Lee Jung-Kun , Shao Lin , Thompson Phillip E.
Published: December 2007

We have studied the mechanisms underlying stress-induced platelet formation during plasma hydrogenation. The stress is purposely introduced by a buried SiGe stained layer in a Si substrate. During plasma hydrogenation, diffusing H is trapped in the region of the SiGe layer and H platelets are formed. The platelet orientation is controlled by the in-plane compressive stress, which favors nucleation and growth of platelets in the plane of stress and parallel to the substrate surface, and ultimately leads to controlled fracture along the SiGe layer. Also, the Si∕SiGe∕Si structure is found to be more efficient in utilizing H for platelet formation and growth compared to H ion implanted Si because there are fewer defects to trap H (e.g., VnHm and InHm); therefore, the total H dose needed for layer exfoliation is greatly reduced.
Second and third order nonlinear optical properties of microrod ZnO films deposited on sapphire substrates by thermal oxidation of metallic zinc
Authors: Kulyk B. , Essaidi Z. , Luc J. , Sofiani Z. , Boudebs G. , Sahraoui B. , Kapustianyk V. , Turko B.
Published: December 2007

We report the preparation of microcrystalline ZnO thin films on sapphire substrates using a simple method based on the thermal evaporation of metallic Zn in vacuum with further annealing process. The aim of annealing in the oxygen atmosphere in the range of 800–850°C was to obtain the high quality ZnO films. The surface morphology was studied by scanning electron microscopy and atomic force microscopy. The polycrystalline films with ZnO microrods at different stages of their growth were investigated. Second and third harmonic generation measurements were performed by means of the rotational Maker fringe technique using Nd:YAG laser at 1064nm in picosecond regime. The obtained values of second and third order nonlinear susceptibilities were found to be high enough for the potential applications of the investigated materials in the optical switching devices based on refractive index changes.
Ion beam formation in a low-pressure geometrically expanding argon plasma
Authors: Corr C. S. , Zanger J. , Boswell R. W. , Charles C.
Published: December 2007

Supersonic ion beam formation has been observed in a geometrically expanding low-pressure inductively coupled argon plasma. It is found that the ion beam is only observed below 3mTorr and only when the discharge is operated in inductive mode. The geometrical expansion of the plasma induces density and potential gradients leading to the ion beam formation. The ion beam energy increases with decreasing source tube radius. The results show that ion beam formation can be achieved by geometrical expansion alone and that the ion beam energy depends on the ratio of the cross-sectional area of the source and expansion region.
AlN avalanche photodetectors
Authors: Dahal R. , Al Tahtamouni T. M. , Lin J. Y. , Jiang H. X.
Published: December 2007

Deep ultraviolet (DUV) avalanche photodetectors (APDs) based on an AlN∕n-SiC Schottky diode structure have been demonstrated. The device with a mesa diameter of ∼100μm exhibits a gain of 1200 at a reverse bias voltage of −250V or a field of about 3MV∕cm. The cut-off and peak responsivity wavelengths of these APDs were 210 and 200nm, respectively. This is the highest optical gain and shortest cut-off wavelength achieved for III-nitride based DUV APDs. It was also observed that the reverse breakdown voltage increases with decreasing device size, which suggests that the device performance is limited by the presence of dislocations. The breakdown voltage for dislocation-free AlN was deduced to be about 4.1MV∕cm. The present results further demonstrate the potential of AlN as an active DUV material for future optoelectronic device applications.
Polymer-metal waveguides characterization by Fourier plane leakage radiation microscopy
Authors: Massenot S. , Grandidier J. , Bouhelier A. , Colas des Francs G. , Markey L. , Weeber J.-C. , Dereux A. , Renger J. , Gonzàlez M. U. , Quidant R.
Published: December 2007

The guiding properties of polymer waveguides on a thin gold film are investigated in the optical regime. The details of propagation in the waveguides are studied simultaneously in the object and Fourier planes, providing direct measurement of both the real and imaginary parts of the effective index of the guided mode. A fair agreement between theoretical analysis provided by the differential method and experimental leakage radiation microscopy data is shown. All these tools bring valuable information for designing and understanding such devices.
Versatile waveguide-coupled optofluidic devices based on liquid core optical ring resonators
Authors: White Ian M. , Gohring John , Sun Yuze , Yang Gilmo , Lacey Scott , Fan Xudong
Published: December 2007

A versatile waveguide-coupled optofluidic device using the liquid core optical ring resonator (LCORR) that can be operated with liquid of any refractive index (RI) is theoretically analyzed and experimentally demonstrated. The results confirm the confinement of resonant modes for all sample RIs, and reveal that confined modes in a high-RI core are excited by an external waveguide by resonant tunneling through the LCORR wall. It is further found that a thin wall must be used for effective interaction between the core mode and the waveguide. The results have important applications in optofluidic devices, including sensors, microfluidic lasers, and nonlinear optics.
Study of stress in a shallow-trench-isolated Si structure using polarized confocal near-UV Raman microscopy of its cross section
Authors: Poborchii Vladimir , Tada Tetsuya , Kanayama Toshihiko
Published: December 2007

Stress in shallow-trench-isolated structures with 250-nm-wide Si stripes was examined by 364nm excitation confocal Raman microscopy. Using objective lenses with the experimentally measured ∼150nm spatial resolution, we studied polarized Raman spectra from the section perpendicular to the stripes. Detection of two optical phonons enabled us to analyze orientation and intensity of local stress quantitatively. Uniaxial [001] compressive stress was found in the Si substrate under both the trench and the stripe, while the stress in the stripe was uniaxial [110] perpendicular to the stripe.
Choices versus Choice Sets: A Commuting Spectrum Method for Representing Job — Housing Possibilities
Authors: Yang Jiawen , Ferreira Joseph
Published: December 2007

Conclusions in empirical studies of commuting and urban spatial structure depend on the selection of measures for the job-housing relationship. In order to help to develop urban growth strategies based on coherent empirical results, this paper presents a ‘commuting spectrum’ approach as an alternative to existing job–housing relationship measures. With this approach, two hypothetical and extreme commuting possibilities are conceptualized as measures for job–housing relationship and location-choice sets. Simulation in a stylized region and empirical results for Boston and Atlanta indicate that the proposed method can track local and regional aspects of job – housing relationship changes. The revealed association between commuting length and the job–housing relationship is consistent from the perspectives of neighborhood-level comparison, multiyear comparison, and interregion comparison.
Cut-off Models for the ‘Go-Home’ Decision of Pedestrians in Shopping Streets
Authors: Zhu Wei , Timmermans Harry
Published: December 2007

Many behavioral and nonbehavioral models have been proposed to model pedestrian behavior. Among these, pedestrians' decision processes have not been explicitly modeled. Utility-maximizing models have been prominently used, but these models may be misspecified owing to their unrealistic assumptions. As an alternative, this paper proposes cut-off models based on the satisficing heuristic founded in bounded rationality theory. The go-home decision of pedestrians in Wang Fujing Street, Beijing, is taken as an example. Results of a multinomial logit model and three cut-off models with increasing complexity are compared. The results show that the cut-off models can fit the data equally as well as the multinomial logit model, suggesting that satisficing heuristics not only have theoretical advantages but also statistical power. Introducing a decision engagement module before the satisficing decision module significantly improves the cut-off model and supports the hypothesis of a hierarchical decision process.
MALE NORMS AND FEMALE ADJUSTMENTS: THE INFLUENCE OF CARE CREDITS ON GENDER PENSION GAPS IN FRANCE AND GERMANY
Authors: Frericks Patricia , Maier Robert , de Graaf Willibrord
Published: December 2007

European pension systems are in the process of change. A general development is the retrenchment of public schemes. In combination with the aim of individualizing pension entitlements, it is crucial that the pension situation of women, and of mothers in particular, be improved. Some European countries attempt to reduce the gender pension gaps with child care credits. This paper takes a closer look at the French and German systems. Can adjustments to the pension norm, in terms of different allowances for child care as introduced in both countries, balance gender pension gaps? Following the logic of the individual factors, the duration of insurance and the level of paid contributions, the main factors are analysed to evaluate the efficiency of care credits. Within the complexity of pension-related factors, adjustments to the originally male pension norms have very ambiguous effects, and they are insufficient to de-gender pension gaps.
PERSISTENT POVERTY: PORTUGAL AND THE SOUTHERN EUROPEAN WELFARE REGIME
Authors: Ferreira Leonor Vasconcelos
Published: December 2007

This article aims to assess the extent to which social policies address current and persistent poverty in southern European Union countries in general and Portugal in particular. The southern European welfare regime, which includes Greece, Italy, Portugal and Spain, has been seen as less developed and less generous in covering social risks. Additionally, the southern European welfare regime presents several inefficiencies that make social policies much less successful in tackling current and persistent poverty. In spite of having recently followed a common path of welfare reforms, southern European countries are far from achieving substantial results in poverty reduction in recent years. Possible explanations of enduring poverty may rest on cultural and institutional factors such as less state accountability in the context where a prominent role in welfare provision rests on families, high levels of tolerance of inequality and poverty, and, in broader terms, in attitudes toward inequality and poverty embedded in social and political practices. In this framework, the case of Portugal is further developed and contrasted with others countries in southern Europe.
THE STATE AND SOCIAL SERVICES IN BRITAIN, FRANCE AND GERMANY SINCE THE 1980s
Authors: Bahle Thomas
Published: December 2007

The article studies the development of social services in Britain, France and Germany since the 1980s. In this period services grew strongly and were extended to large population groups, although the welfare state was in crisis. Moreover, the power of the state was enhanced. The share of public service provision declined somewhat, but this was more than balanced by increased public funding and intensified state control of delivery. The paper argues that the rise of social services does not signal a ‘new’ welfare state. Rather, the belated expansion of social services compared to other areas is explained by the fact that services have become crucial for the economy and the labour market only recently. Since this was the case, they have followed the classical path of welfare state expansion.
FREE TO MOVE?: THE ACCEPTANCE OF FREE MOVEMENT OF LABOUR AND NON DISCRIMINATION AMONG CITIZENS OF EUROPE
Authors: Gerhards Jürgen
Published: December 2007

The article first describes how the European Union has replaced the idea of nationally bounded freedom to move, settle, and work with the idea of free movement for all Europeans and the notion of non-discrimination. The second section gives an analysis of the extent to which citizens of different European countries support the idea of non-discrimination between nationals and European foreigners. The empirical basis for our analysis is the ‘European Values Study’. The descriptive findings show that the idea of non-discrimination is not supported by the majority of the European citizens, and that there are substantial differences between the countries. In the third section, we explain these differences by referring, among other factors, to the level of modernization of a country, the value orientation of the respondent, the level of education of the respondent, and the unemployment rate.
GENDER, CULTURE AND NON-FINANCIAL EMPLOYMENT COMMITMENT IN GREAT BRITAIN AND SWEDEN
Authors: Hult Carl
Published: December 2007

The main question this paper seeks to tackle is whether men and women, as some argue, commit themselves to employment differently or for different reasons. The focus is thus on the mechanisms behind non-financial employment commitment (such as the possible effect of family situation, occupational position, and of different work-related preferences and experiences). The question is comparatively investigated in Sweden and Great Britain, where, in spite of many similarities, the existence of different societal/cultural contexts with relevance for gender and work has been suggested. The results in this paper suggest that the most important motivator for non-financial employment commitment is interesting work, which was found to have a positive effect both as a work goal and as experienced in the workplace. Although women and men in both countries displayed quite similar patterns, some country and gender differences appeared in the way occupational position and degree of education relate to this type of commitment. Higher occupational position and education where more clearly related to higher degrees of commitment for British women than for British men, while the Swedish gender pattern was reversed. In the concluding discussion, possible explanations and implications are discussed, and avenues for further research are suggested.
Vendor‐supplied usage data for electronic resources: a survey of academic libraries
Authors: BAKER Gayle , READ Eleanor J.
Published: December 2007

A survey was sent to research libraries in the United States and Canada to learn about the level of effort involved in working with vendors' usage reports, how the data are used, and which data are most useful to librarians in managing electronic resources. Ninety‐two responses were received and analyzed. Lack of standards and inconsistencies in the usage data were identified as issues in effectively preparing the data for further analysis. In fact, the results showed that more time was spent acquiring, reformatting, and manipulating the data than on actually analyzing them. The number of full‐text downloads was specified as the most useful statistic for assessing the use of electronic resources.
What do society and association members really want?
Authors: WALTHAM Mary
Published: December 2007

Discussion among professional and learned society staff about what their members really want now ranges across such a broad spectrum of services that it is often difficult to focus on the question. That said, the responses tend to be relatively simple. They often take the form of folk wisdom, proverbs handed down from one generation to the next that are not so much inaccurate as sometimes unhelpful. Members are variously described as joining to receive the journal, to attend the meetings, to get cheaper insurance, to pay lower page charges, and so on. This article goes beyond the proverbs, by looking at real evidence and emerging trends in society membership and publications. The aim is to support pragmatic decision‐making by society and association publishers in a world where membership ‘to get the journal’ is no longer necessarily the norm.
Choosing a publishing partner: advice for societies and associations
Authors: WARE Mark
Published: December 2007

For societies and associations seeking a publishing partner, the healthy competition between publishers means that the deals on offer have never been better. The problem for the society is distinguishing a good short‐term deal (say, an attractive financial offer) from the partnership that will actually be in the better long‐term interests of the journal. This article, based on the author's experience as a publisher‐turned‐consultant advising societies, offers a framework for selecting a partner based on a careful analysis of what the society needs from its publisher in the long term. Underlying the performance of the best publisher partners are a good understanding of the needs of societies and their journals; a strong service orientation; and an ability to plan strategically for each journal on the basis of facts and data.
Integrating research articles and supporting data in crystallography
Authors: STRICKLAND Peter R. , McMAHON Brian , HELLIWELL John R.
Published: December 2007

The development by a scientific learned society of data description and exchange standards has revolutionized the publication of journal articles in crystallography. Data validation has become an essential element in peer review. Submission, review, and handling of articles are carried out faster, more efficiently, and more consistently. The full data to support a scientific model are made available to the reader, allowing molecular structures to be visualized and analysed. The journals provide a much more complete account of the scientific record, in a model that should appeal to other data‐rich scientific disciplines.
For a few dollars more: a future for scholarly books in Australia?
Authors: DERRICOURT Robin
Published: December 2007

Australia's universities have seen significant growth in government research funding, with more to come, but this is not reflected in the output of research monograph publications; structural barriers stand between creation and dissemination of research. This is especially a problem for those working on Australian topics. The author has proposed a new model for funding scholarly publishing in Australia, which may well be applicable to other countries: just a small proportion of the funds committed by the Australian government to research inputs could ensure the publication of research outputs. This would deliver major gains in impact and productivity for government, universities, and individual academics alike.
Minimal bounded index subgroup for dependent theories
Authors: Shelah Saharon
Published: December 2007

For a dependent theory

T
T

, in

C

T

{\mathfrak {C}}_{T}

for every type definable group

G
G

, the intersection of type definable subgroups with bounded index is a type definable subgroup with bounded index.
A sharp bound for the Stein-Wainger oscillatory integral
Authors: Parissis Ioannis
Published: December 2007

Let

P

d

\mathcal {P}_d

denote the space of all real polynomials of degree at most

d
d

. It is an old result of Stein and Wainger that
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="sup Underscript upper P element-of script upper P Subscript d Baseline Endscripts StartAbsoluteValue p period v period integral Underscript double-struck upper R Endscripts e Superscript i upper P left-parenthesis t right-parenthesis Baseline StartFraction d t Over t EndFraction EndAbsoluteValue less-than-or-equal-to upper C Subscript d">

sup

P
∈

P

d

|

p
.
v
.

∫

R

e

i
P
(
t
)

d
t

t

|

≤

C
d

\sup _ {P\in \mathcal {P}_d} \bigg |p.v.\int _{\mathbb {R}} {e^{iP(t)}\frac {dt}{t}} \bigg |\leq C_d

\]
for some constant

C
d

C_d

depending only on

d
d

. On the other hand, Carbery, Wainger and Wright claim that the true order of magnitude of the above principal value integral is

log
⁡
d

\log d

. We prove that
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="sup Underscript upper P element-of script upper P Subscript d Baseline Endscripts StartAbsoluteValue p period v period integral Underscript double-struck upper R Endscripts e Superscript i upper P left-parenthesis t right-parenthesis Baseline StartFraction d t Over t EndFraction EndAbsoluteValue tilde log d period">

sup

P
∈

P

d

|

p
.
v
.

∫

R

e

i
P
(
t
)

d
t

t

|

∼
log
⁡

d

.

\sup _ {P\in \mathcal {P}_d}\bigg |p.v. \int _{\mathbb {R}}{e^{iP(t)}\frac {dt}{t}}\bigg |\sim \log {d}.

\]
Core of ideals of Noetherian local rings
Authors: Wang Hsin-Ju
Published: December 2007

The core of an ideal is the intersection of all its reductions. In 2005, Polini and Ulrich explicitly described the core as a colon ideal of a power of a single reduction and a power of

I
I

for a broader class of ideals, where

I
I

is an ideal in a local Cohen-Macaulay ring. In this paper, we show that if

I
I

is an ideal of analytic spread

1
1

in a Noetherian local ring with infinite residue field, then with some mild conditions on

I
I

, we have
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="c o r e left-parenthesis upper I right-parenthesis superset-of-or-equal-to upper J left-parenthesis upper J Superscript n Baseline colon upper I Superscript n Baseline right-parenthesis equals upper I left-parenthesis upper J Superscript n Baseline colon upper I Superscript n Baseline right-parenthesis equals left-parenthesis upper J Superscript n plus 1 Baseline colon upper I Superscript n Baseline right-parenthesis intersection upper I">

core
⁡
(
I
)
⊇
J
(

J
n

:

I
n

)
=
I
(

J
n

:

I
n

)
=
(

J

n
+
1

:

I
n

)
∩
I

\operatorname {core} (I)\supseteq J(J^n: I^n)=I(J^n: I^n)=(J^{n+1}: I^n)\cap I

for any minimal reduction

J
J

of

I
I

and for

n
≫
0

n\gg 0

.
Wavelet multipliers on 𝐿^{𝑝}(ℝⁿ)
Authors: Liu Yu , Mohammed Alip , Wong M.
Published: December 2007

We give results on the boundedness and compactness of wavelet multipliers on

L
p

(

R

n

)
,

1
≤
p
≤
∞

L^p(\mathbb {R}^n),\,1\leq p\leq \infty

.
Constructing units in product systems
Authors: Liebscher Volkmar , Skeide Michael
Published: December 2007

We prove a criterion that allows us to construct units in product systems of correspondences with prescribed infinitesimal characterizations. This criterion summarizes proofs of known results and new applications. It also frees the hypotheses from the assumption that the units are contained in a product system of time ordered Fock modules.
Self-similarity in viscous Boussinesq equations
Authors: Karch Grzegorz , Prioux Nicolas
Published: December 2007

We study the existence and the asymptotic stability as the time variable escapes to infinity of self-similar solutions to the viscous Boussinesq equations posed in the whole three dimensional space.
All-time Morse decompositions of linear nonautonomous dynamical systems
Authors: Rasmussen Martin
Published: December 2007

Morse decompositions provide inside information about the global asymptotic behavior of dynamical systems on compact metric spaces. Recently, the existence of Morse decompositions for nonautonomous dynamical systems was proved by restricting attention to the past or the future of the system, but in general, such a construction is not realizable for the entire time. In this article, it is shown that all-time Morse decompositions can be defined for linear systems on the projective space. Moreover, the dynamical properties are discussed and an analogue to the Theorem of Selgrade is proved.
Characterizations of Disjointness preserving operators on vector-valued function spaces
Authors: Jeang Jyh-Shyang , Lin Ying-Fen
Published: December 2007

We characterize compact and completely continuous disjointness preserving linear operators on vector-valued continuous functions as follows: a disjointness preserving operator

T
:

C
0

(
X
,
E
)
→

C
0

(
Y
,
F
)

T : C_0(X, E) \to C_0(Y, F)

is compact (resp. completely continuous) if and only if
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="StartLayout 1st Row upper T f equals sigma-summation Underscript n Endscripts delta Subscript x Sub Subscript n Subscript Baseline circled-times h Subscript n Baseline left-parenthesis f right-parenthesis for all f element-of upper C 0 left-parenthesis upper X comma upper E right-parenthesis comma EndLayout">

T
f
=

∑
n

δ

x
n

⊗

h
n

(
f
)

for all 
f
∈

C
0

(
X
,
E
)
,

\begin{align*} Tf = \sum _n \delta _{x_n} \otimes h_n (f) \quad \text {for all } f \in C_0(X,E), \end{align*}

where

h
n

:
Y
→
B
(
E
,
F
)

h_n : Y \to B(E,F)

is continuous and vanishes at infinity in the uniform (resp. strong) operator topology, and

h
n

(
y
)

h_n(y)

is compact (resp. 

h
n

h_n

is uniformly completely continuous).
Fixed points and stability in neutral differential equations with variable delays
Authors: Jin Chuhua , Luo Jiaowan
Published: December 2007

In this paper we consider a linear scalar neutral delay differential equation with variable delays and give some new conditions to ensure that the zero solution is asymptotically stable by means of fixed point theory. These conditions do not require the boundedness of delays, nor do they ask for a fixed sign on the coefficient functions. An asymptotic stability theorem with a necessary and sufficient condition is proved. The results of Burton, Raffoul, and Zhang are improved and generalized.
Pseudocompact totally dense subgroups
Authors: Dikranjan Dikran , Bruno Anna
Published: December 2007

It was shown by Dikranjan and Shakhmatov in 1992 that if a compact abelian group

K
K

admits a proper totally dense pseudocompact subgroup, then

K
K

cannot have a torsion closed

G
δ

G_\delta

-subgroup; moreover this condition was shown to be also sufficient under LH. We prove in ZFC that this condition actually ensures the existence of a proper totally dense subgroup

H
H

of

K
K

that contains an

ω
\omega

-bounded dense subgroup of

K
K

(such an

H
H

is necessarily pseudocompact). This answers two questions posed by Dikranjan and Shakhmatov (Proc. Amer. Math. Soc. 114 (1992), 1119–1129).
Manifolds: Hausdorffness versus homogeneity
Authors: Baillif Mathieu , Gabard Alexandre
Published: December 2007

We analyze the relationship between Hausdorffness and homogeneity in the frame of manifolds not confined to be Hausdorff. We exhibit examples of homogeneous non-Hausdorff manifolds and prove that a Lindelöf homogeneous manifold is Hausdorff.
Embeddings of locally finite metric spaces into Banach spaces
Authors: Baudier F. , Lancien G.
Published: December 2007

We show that if

X
X

is a Banach space without cotype, then every locally finite metric space embeds metrically into

X
X

.
Convex solids with planar midsurfaces
Authors: Soltan Valeriu
Published: December 2007

We show that the boundary of annn-dimensional closed convex setB⊂RnB \subset \mathbb {R}^n, possibly unbounded, is a convex quadric surface if and only if the middle points of every family of parallel chords ofBBlie in a hyperplane. To prove this statement, we show that the boundary ofBBis a convex quadric surface if and only if there is a pointp∈intBp \in \mathrm {int}\,Bsuch that all sections ofbdB\mathrm {bd}\,Bby 2-dimensional planes throughppare convex quadric curves. Generalizations of these statements that involve boundedly polyhedral sets are given.
Large groups and their periodic quotients
Authors: Olshanskii A. , Osin D.
Published: December 2007

We first give a short group theoretic proof of the following result of Lackenby. If

G
G

is a large group,

H
H

is a finite index subgroup of

G
G

admitting an epimorphism onto a non-cyclic free group, and

g
1

,
…
,

g
k

g_1, \ldots , g_k

are elements of

H
H

, then the quotient of

G
G

by the normal subgroup generated by

g
1
n

,
…
,

g
k
n

g_1^n, \ldots , g_k^n

is large for all but finitely many

n
∈

Z

n\in \mathbb Z

. In the second part of this note we use similar methods to show that for every infinite sequence of primes

(

p
1

,

p
2

,
…
)

(p_1, p_2, \ldots )

, there exists an infinite finitely generated periodic group

Q
Q

with descending normal series

Q
=

Q
0

⊳

Q
1

⊳
…

Q=Q_0\rhd Q_1\rhd \ldots

, such that

⋂
i

Q
i

=
{
1
}

\bigcap _i Q_i=\{ 1\}

and

Q

i
−
1

/

Q
i

Q_{i-1}/Q_i

is either trivial or abelian of exponent

p
i

p_i

.
A note on equilibrium points of Green’s function
Authors: Solynin Alexander
Published: December 2007

We answer a question raised by Ahmet Sebbar and Thérèse Falliero (2007) by showing that for every finitely connected planar domain

Ω
\Omega

there exists a compact subset

K
⊂
Ω

K\subset \Omega

, independent of

w
w

, containing all critical points of Green’s function

G
(
z
,
w
)

G(z,w)

of

Ω
\Omega

with pole at

w
∈
Ω

w\in \Omega

.
Homeomorphisms of the 3-sphere that preserve a Heegaard splitting of genus two
Authors: Cho Sangbum
Published: December 2007

Let

H

2

{\mathcal H_2}

be the group of isotopy classes of orientation-preserving homeomorphisms of

S

3

\mathbb S^3

that preserve a Heegaard splitting of genus two. In this paper, we construct a tree in the barycentric subdivision of the disk complex of a handlebody of the splitting to obtain a finite presentation of

H

2

{\mathcal H_2}

.
Rainbow decompositions
Authors: Yuster Raphael
Published: December 2007

A rainbow coloring of a graph is a coloring of the edges with distinct colors. We prove the following extension of Wilson’s Theorem. For every integer

k
k

there exists an

n
0

=

n
0

(
k
)

n_0=n_0(k)

so that for all

n
>

n
0

n > n_0

, if
\[

n
mod
k
(
k
−
1
)
∈
{
1
,
k
}
,

n \bmod k(k-1) \in \{1,k\},

\]
then every properly edge-colored

K
n

K_n

contains

(

n
2

)

/

(

k
2

)

\binom {n}{2}/\binom {k}{2}

pairwise edge-disjoint rainbow copies of

K
k

K_k

. Our proof uses, as a main ingredient, a double application of the probabilistic method.
The best constant in a weighted Hardy-Littlewood-Sobolev inequality
Authors: Chen Wenxiong , Li Congming
Published: December 2007

We prove the uniqueness for the solutions of the singular nonlinear PDE system:
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="StartLayout 1st Row with Label left-parenthesis 1 right-parenthesis EndLabel StartLayout Enlarged left-brace 1st Row minus delta left-parenthesis StartAbsoluteValue x EndAbsoluteValue Superscript alpha Baseline u left-parenthesis x right-parenthesis right-parenthesis equals StartFraction v Superscript q Baseline left-parenthesis x right-parenthesis Over StartAbsoluteValue x EndAbsoluteValue Superscript beta Baseline EndFraction comma 2nd Row minus delta left-parenthesis StartAbsoluteValue x EndAbsoluteValue Superscript beta Baseline v left-parenthesis x right-parenthesis right-parenthesis equals StartFraction u Superscript p Baseline left-parenthesis x right-parenthesis Over StartAbsoluteValue x EndAbsoluteValue Superscript alpha Baseline EndFraction period EndLayout EndLayout">

(1)

{

−
δ
(

|

x

|

α

u
(
x
)
)
=

v
q

(
x
)

|

x

|

β

,

−
δ
(

|

x

|

β

v
(
x
)
)
=

u
p

(
x
)

|

x

|

α

.

\begin{equation}\tag {1} \begin {cases} - \delta ( |x|^{\alpha } u(x) ) = \dfrac {v^q (x)}{|x|^{\beta }} ,\\ - \delta ( |x|^{\beta } v(x) ) = \dfrac {u^p (x)}{|x|^{\alpha }}. \end{cases} \end{equation}

In the special case when

α
=
β

\alpha = \beta

and

p
=
q

p = q

, we classify all the solutions and thus obtain the best constant in the corresponding weighted Hardy-Littlewood-Sobolev inequality.
On the ground state energy of the translation invariant Pauli-Fierz model
Authors: Barbaroux Jean-Marie , Chen Thomas , Vougalter Vitali , Vugalter Semjon
Published: December 2007

In this note, we determine the ground state energy of the translation invariant Pauli-Fierz model to subleading order

O
(

α
3

)

O(\alpha ^3)

with respect to powers of the finestructure constant

α
\alpha

and prove rigorous error bounds of order

O
(

α

4

)

O(\alpha ^{4})

. A main objective of our argument is its brevity.
On the 𝐶^{∞} wave-front set of traces of CR functions on maximally real submanifolds
Authors: Adwan Z. , Hoepfner G.
Published: December 2007

We prove that, in a locally integrable structure, the

C

∞

C^{\infty }

wave-front set of the trace of a CR function at a point

p
p

in a totally real submanifold of maximal dimension is independent of the maximally real submanifold passing through the point

p
p

.
On the combinatorics of crystal graphs, II. The crystal commutor
Authors: Lenart Cristian
Published: December 2007

We present an explicit combinatorial realization of the commutor in the category of crystals which was first studied by Henriques and Kamnitzer. Our realization is based on certain local moves defined by van Leeuwen.
Hypersurfaces whose tangent geodesics do not cover the ambient space
Authors: Mendonça Sérgio , Mirandola Heudson
Published: December 2007

Let

x
:

Σ
n

→

M

n
+
1

x:\Sigma ^n\rightarrow M^{n+1}

be an immersion of an

n
n

-dimensional connected manifold

Σ
\Sigma

in an

(
n
+
1
)

(n+1)

-dimensional connected complete Riemannian manifold

M
M

without conjugate points. Assume that the union of geodesics tangent to

x
x

does not cover

M
M

. Under these hypotheses we have two results. The first one states that

M
M

is simply connected provided that the universal covering of

Σ
\Sigma

is compact. The second result says that if

x
x

is a proper embedding and

M
M

is simply connected, then

x
(
Σ
)

x(\Sigma )

is a normal graph over an open subset of a geodesic sphere. Furthermore, there exists an open star-shaped set

A
⊂
M

A\subset M

such that

A
¯

\bar A

is a manifold with the boundary

x
(
Σ
)

x(\Sigma )

.