bluuebunny/crossref_metadata_2025 huggingface dataset:
Dielectric properties of fluorocarbon thin films deposited by radio frequency sputtering of polytetrafluoroethylene
Authors: Gonon P. , Sylvestre A.
Published: October 2002

We investigate the dielectric properties of fluorocarbon thin films deposited by radio-frequency magnetron sputtering of polytetrafluroethylene. The dielectric constant and the loss factor are studied as a function of frequency (0.1 Hz-1 MHz, infrared frequencies) and temperature (room temperature to 100 °C). The value of the dielectric constant is 1.8 at optical frequencies, and around 2.3 in the 0.1 Hz–1 MHz range. The background loss factor is around 0.8% in these samples. Two different polarization mechanisms are identified (β and γ relaxations). The γ process dominates the dielectric constant from 0.1 to 1 MHz. In this frequency range the dielectric constant decreases with temperature (about –4% from room temperature to 100 °C). Temperature dependence of the dielectric constant is well described by a simple Debye model (linear variation of the dielectric constant with 1/T). The γ relaxation is tentatively ascribed to C−F bonds (Nμ2=4×10−32 C2 m−1). The β relaxation has a loss peak located at very low frequencies (<0.1 Hz). It leads to an increase of loss below 10 Hz when temperature is increased above 75 °C. The high-frequency part of the β loss peak decreases as ω−0.35. Study of its temperature dependence leads to an activation energy of 0.66 eV.
Effects of orientation on the strength of the aluminum alloy 7010-T6 during shock loading: Experiment and simulation
Authors: Vignjevic R. , Bourne N. K. , Millett J. C. F. , De Vuyst T.
Published: October 2002

The shock response of the aluminum alloy 7010-T6, induced by the technique of plate impact, has been investigated as a function of orientation to the loading axis to the rolling direction. Measurements of the Hugoniot elastic limit (HEL) and spall strength show that the material is stronger in the longitudinal orientation than the short transverse, in keeping with the mechanical properties measured at quasistatic strain rates. Furthermore, a comparison of the HELs to the 0.2% proof stresses suggests that there is a degree of strain-rate sensitivity in the longitudinal orientation, whilst the short transverse appears strain-rate insensitive. Thus, there exists the possibility that strain-rate sensitivity itself is orientation dependent in this alloy. Comparison of the ratios of spall strength according to orientation, to the equivalent quasistatic yield strengths provides further evidence of this hypothesis. A simulation using finite-element modeling has shown that while the model can reproduce the dependency of the HEL on orientation, the degree of success with the spall strength has not been so great.
Determination of full set material constants of piezoceramics from phase velocities
Authors: Wang Haifeng , Cao Wenwu
Published: October 2002

The determination of elastic and piezoelectric constants by means of the resonance method is described in detail in the Institute of Electrical and Electronics Engineers Standards. However, in practice, it is not easy to obtain a self-consistent complete set of elastic and piezoelectric coefficients using the resonance method alone, since the geometric requirements are often too difficult to meet in some materials and property variation from sample to sample could be substantial. In this article, we report on a characterization scheme by regression of ultrasonic velocities in different directions. The method using the Levenberg-Marquardt algorithm is very stable. Only two samples are needed to determine the whole set of the material constants. The method has been applied to doped piezoceramic lead zirconate titanate and material constants obtained at the same frequency show excellent self-consistency.
Signatures of site-specific reaction of H2 on Cu(100)
Authors: Somers M. F. , McCormack D. A. , Kroes G. J. , Olsen R. A. , Baerends E. J. , Mowrey R. C.
Published: October 2002

Six-dimensional quantum dynamical calculations are presented for the reaction of (v,j) H2 on Cu(100), at normal incidence, for v=0–1 and j=0–5. The dynamical calculations employed a potential energy surface computed with density functional theory, using the generalized gradient approximation and a slab representation for the adsorbate-substrate system. The aim of the calculations was to establish signatures from which experiments could determine the dominant reaction site of H2 on the surface and the dependence of the reaction site on the initial rovibrational state of H2. Two types of signatures were found. First, we predict that, at energies near threshold, the reaction of (v=1) H2 is rotationally enhanced, because it takes place at the top site, which has an especially late barrier and a reaction path with a high curvature. On the other hand, we predict the reaction to be almost independent of j for (v=0) H2, which reacts at the bridge site. Second, we predict that, at collision energies slightly above threshold for which the reaction probabilities of the (v=0) and (v=1) states are comparable, the rotational quadrupole alignment of (v=1) reacting molecules should be larger than that of (v=0) reacting molecules, for j=1, 4, and 5. For (j=2) H2, the opposite should be true, and for (j=3) H2, the rotational quadrupole alignment should be approximately equal for (v=1) and (v=0) H2. These differences can all be explained by the difference in the predicted reaction site for (v=1) and (v=0) H2 (top and bridge) and by the differences in the anisotropy of the potential at the reaction barrier geometries associated with these sites. Our predictions can be tested in associative desorption experiments, using currently available experimental techniques.
Peptide conformational heterogeneity revealed from nonlinear vibrational spectroscopy and molecular-dynamics simulations
Authors: Woutersen Sander , Pfister Rolf , Hamm Peter , Mu Yuguang , Kosov Daniel S. , Stock Gerhard
Published: October 2002

Nonlinear time-resolved vibrational spectroscopy is used to compare spectral broadening of the amide I band of the small peptide trialanine with that of N-methylacetamide, a commonly used model system for the peptide bond. In contrast to N-methylacetamide, the amide I band of trialanine is significantly inhomogeneously broadened. Employing classical molecular-dynamics simulations combined with density-functional-theory calculations, the origin of the spectral inhomogeneity is investigated. While both systems exhibit similar hydrogen-bonding dynamics, it is found that the conformational dynamics of trialanine causes a significant additional spectral broadening. In particular, transitions between the poly(Gly)II and the αR conformations are identified as the main source of the additional spectral inhomogeneity of trialanine. The experimental and computational results suggest that trialanine adopts essentially two conformations: poly(Gly)II (80%) and αR (20%). The potential of the joint experimental and computational approach to explore conformational dynamics of peptides is discussed.
Magnetization reversal in GaMnAs layers studied by Kerr effect
Authors: Hrabovsky D. , Vanelle E. , Fert A. R. , Yee D. S. , Redoules J. P. , Sadowski J. , Kanski J. , Ilver L.
Published: October 2002

In this letter, magnetization reversal is investigated in (Ga,Mn)As thin films using the magneto-optical Kerr effect. A Stoner–Wohlfart model, modified to take into account the existence of magnetic reversal discontinuities associated with nucleation and propagation phenomena allows us to estimate most of the characteristic constants. These results demonstrate a reversal behavior analogous to that observed in metallic magnetic layers (coherent rotation followed by a nucleation propagation process). The dynamic study at T=20 K shows a strong increase of the coercivity with the increase of dH/dt. This effect is related to the random distribution of Mn magnetic ions in the lattice.
Statistical thermodynamics of lattice polymer fluid
Authors: Li Xiaoyi , Zhao Delu
Published: October 2002

We obtain the partition function and the complete thermodynamic description for pure polymer fluids on a lattice model. The analytical expressions of thermodynamic quantities are presented in the present theory. The interaction dependence of partition function is included in our theory, which induces the interaction and temperature dependence of entropy. The overall entropy of the system has three fundamentally different types of contributions, i.e., the translational entropy, the configurational entropy and the thermal correction entropy. The second type contributes the main part, while the temperature and interaction energy dependence of entropy emerges from the third type contribution that is absent in Flory–Huggins theory and lattice fluid (LF) theory. The equation of state for pure polymer fluid is obtained and the parameters in it are determined. With the introduction of large coordination number approximate to the present theory, the LF theory is recovered. Compared with LF theory and experimental data, it has been demonstrated that the present theory is capable of adequately describing thermodynamic quantities of pure polymer fluids.
New ideas for using contracted basis functions with a Lanczos eigensolver for computing vibrational spectra of molecules with four or more atoms
Authors: Wang Xiao-Gang , Carrington Tucker
Published: October 2002

We propose new methods for using contracted basis functions in conjunction with the Lanczos algorithm to calculate vibrational (or rovibrational) spectra. As basis functions we use products of eigenfunctions of reduced-dimension Hamiltonians obtained by freezing coordinates at equilibrium. The basis functions represent the desired wave functions well, yet are simple enough that matrix-vector products may be evaluated efficiently. The methods we suggest obviate the need to transform from the contracted to an original product basis each time a matrix-vector product is evaluated. For HOOH the most efficient of the methods we present is about an order of magnitude faster than a product basis Lanczos calculation.
Global fluid phase behavior in binary mixtures of rodlike and platelike molecules
Authors: Varga Szabolcs , Galindo Amparo , Jackson George
Published: October 2002

The phase behavior of a liquid-crystal forming model colloidal system containing hard rodlike and platelike particles is studied using the Parsons–Lee scaling [J. D. Parsons, Phys. Rev. A 19, 1225 (1979); S. D. Lee, J. Chem. Phys. 87, 4972 (1987)] of the Onsager theory. The rod and plate molecules are both modeled as hard cylinders. All of the mixtures considered correspond to cases in which the volume of the plate is orders of magnitude larger that the volume of the rod, so that an equivalence can be made where the plates are colloidal particles while the rods play the role of a depleting agent. A combined analysis of the isotropic–nematic bifurcation transition and spinodal demixing is carried out to determine the geometrical requirements for the stabilization of a demixing transition involving two isotropic phases. Global phase diagrams are presented in which the boundaries of isotropic phase demixing are indicated as functions of the molecular parameters. Using a parameter z which corresponds to the product of the rod and plate aspect ratios, it is shown that the isotropic phase is unstable relative to a demixed state for a wide range of molecular parameters of the constituting particles due to the large excluded volume associated with the mixing of the unlike particles. However, the stability analysis indicates that for certain aspect ratios, the isotropic–nematic phase equilibria always preempts the demixing of the isotropic phase, irrespective of the diameters of the particles. When isotropic–isotropic demixing is found, there is an upper bound at large size ratios (Asakura and Oosawa limit), and a lower bound at small size ratios (Onsager limit) beyond which the system exhibits a miscible isotropic phase. It is very gratifying to find both of these limits within a single theoretical framework. We test the validity of the stability analysis proposed by calculating a number of phase diagrams of the mixture for selected molecular parameters. As the hard rod particles promote an effective attractive interaction between the hard-plate colloidal particles, the isotropic–isotropic demixing usually takes place between two rod-rich fluids. As far as the isotropic–nematic transition is concerned, a stabilization as well as a destabilization of the nematic phase relative to the isotropic phase is seen for varying rod–plate size ratios. Moreover, isotropic–nematic azeotropes and re-entrant phenomena are also observed in most of the mixtures studied. We draw comparisons between the predicted regions of stability for isotropic demixing and recent experimental observations.
Performance analysis of lateral p–n junction laser-transistor
Authors: Ryzhii V. , Satou A. , Khmyrova I. , Ikegami T. , Kubota K. , Vaccaro P. O. , Zanardi Ocampo J. M. , Aida T.
Published: October 2002

We study the performance of a lateral p–n junction quantum-well edge-emitting laser-transistor with an extra gate contact. The incorporation of the gate contact provides an opportunity to control the threshold current and output optical power by the gate voltage. The application of negative gate voltages can lead to a substantial decrease in the threshold current. This is due to the confinement of the electrons injected into the p-type portion of the quantum well serving as the active region. Using the developed device model, we calculate the laser-transistor threshold and output characteristics. We also estimate the device cutoff modulation frequency associated with the gate recharging.
Frequency modulation response of a liquid-crystal electro-optic device doped with nanoparticles
Authors: Shiraishi Yukihide , Toshima Naoki , Maeda Kenji , Yoshikawa Hiroaki , Xu Jun , Kobayashi Shunsuke
Published: October 2002

Palladium nanoparticles covered with liquid-crystal molecules were prepared by UV irradiation of an alcohol solution of palladium(II) acetate in the presence of liquid-crystal molecules. The prepared Pd nanoparticles have an average diameter of 2.5 nm. A twisted nematic (TN) liquid-crystal device (LCD) was fabricated by doping with Pd nanoparticles covered with another kind of nematic liquid-crystal molecules. In this device the sign of the dielectric anisotropy (Δε) of the liquid-crystal molecules, which cover Pd nanoparticles, is opposite to that of nematic liquid-crystal molecules, which work as the host of the device (Δε>0). The TN-LCD cell fabricated in this research exhibits a frequency modulation response to an applied alternative voltage wave form.
Mechanical properties and interfacial characteristics of carbon-nanotube-reinforced epoxy thin films
Authors: Xu Xiaojing , Thwe Moe Moe , Shearwood Christopher , Liao Kin
Published: October 2002

Multiwalled carbon nanotubes (MWNT) reinforced epoxy composite thin films were prepared by a microfabrication process and their elastic modulus was determined using a shaft-loaded blister test and linear and nonlinear elasticity models. Compared to net resin thin films, a 20% increase in elastic modulus was seen when 0.1 wt % MWNTs were added, suggesting MWNT alignment by spin coating. Electron microscopic observations of the fracture surfaces suggested high interfacial shear stress between MWNTs and the epoxy matrix, a result supported by both molecular mechanics simulation and micromechanics calculations.
Low-threshold photonic crystal laser
Authors: Lončar Marko , Yoshie Tomoyuki , Scherer Axel , Gogna Pawan , Qiu Yueming
Published: October 2002

We have fabricated photonic crystal nanocavity lasers, based on a high-quality factor design that incorporates fractional edge dislocations. Lasers with InGaAsP quantum well active material emitting at 1550 nm were optically pumped with 10 ns pulses, and lased at threshold pumping powers below 220 μW, the lowest reported for quantum-well based photonic crystal lasers, to our knowledge. Polarization characteristics and lithographic tuning properties were found to be in excellent agreement with theoretical predictions.
Anomalies of the electronic heat capacity of thulium cuprates in the pseudogap phase region
Authors: Amitin E. B. , Zhdanov K. R. , Kameneva M. Yu. , Kovalevskaya Yu. A. , Kozeeva L. P. , Paukov I. E. , Blinov A. G.
Published: October 2002

Precision measurements of the heat capacity of thulium 1-2-3 cuprate with oxygen concentrations x=6.92 and x=6.7 are made in the temperature range 6–300 K. After the lattice components of the heat capacity of the samples are subtracted off, a comparison of the results makes it possible to determine the contribution to the heat capacity due to the formation of the pseudogap phase for the sample with x=6.7. The temperature dependence of this contribution has an anomaly near the boundary of the transition from the pseudogap phase to the normal metallic phase. The experimental results correlate with the theoretical ideas about the rearrangement of the electronic structure upon the transition of the system to the pseudogap phase region.
Atomic disorder in Heusler Co2MnGe measured by anomalous x-ray diffraction
Authors: Ravel B. , Cross J. O. , Raphael M. P. , Harris V. G. , Ramesh R. , Saraf L. V.
Published: October 2002

Heusler alloys Co2MnX, where X is Ge or Si, are predicted by the band theory to be a half-metallic ferromagnets, i.e., metals with all conduction electrons of the same spin state. To date, Heusler alloys have been measured with spin polarizations of 50%–60%, higher than Fe (∼40%), but not a true half metal. Structural defects involving site swapping between the Co and Mn sublattices have been proposed as a mechanism to diminish spin polarization. In this work, we present an anomalous x-ray diffraction measurement on Co2MnGe to determine antisite disorder in thin films with a high precision.
Microwire arrays with plasmonic response at microwave frequencies
Authors: Gay-Balmaz Philippe , Maccio Claudio , Martin Olivier J. F.
Published: October 2002

We study experimentally the response of three-dimensional arrays of microscopic wires. Very good agreement is found with previous theoretical work indicating that such a system can be considered as an effective plasmonic medium with a specific plasma frequency. The sample size threshold where this effective behavior appears is shown to be relatively small.
How to Proceed from Image and Discourse to Action: As Applied to the Flemish Diamond
Authors: Albrechts Louis
Published: October 2002

For several polynuclear urban areas (Randstad, Ruhr, Flemish Diamond), (loose) visions, images and planning discourses have been conceived. Nevertheless, one has to conclude that no or very few of these visions, images, discourses have led to actions. This paper explores some lines of thought to bridge the gap between idea and action in polynucleated urban areas. The focus is on the type of planning needed, the kind of issues that could be tackled and the institutions needed to initiate the necessary co-operation between stakeholders—public and private—playing a role in polynucleated urban areas. The Flemish Diamond is treated as a deliberate attempt to use a new type of strategic planning to tackle this polynucleated urban area in an integrated way. The approach is influenced by more general principles derived from planning literature, the authors' own professional experience and the specificity of one particular case: the Flemish Diamond. The paper focuses on the design of arenas (forums) in polynucleated urban areas, the selection of strategic issues and the support of the planning process.
The Tenure Imbalance in Spain: The Need for Social Housing Policy
Authors: Pareja Eastaway Montserrat , Varo Ignacio San Martin
Published: October 2002

Spain is usually chosen as an example of an unbalanced picture among tenures. The owner-occupied sector has been growing since the 1950s while the rental sector has become smaller. Surprisingly, other European countries are at present following the same pattern, but mostly we also see an important function for social housing. Taking into account that public housing, built by public developers, is almost negligible and that government housing policy programmes basically stimulate ownership, the 'social housing' concept lacks an adequate definition in Spanish housing policy. In this sense, the encouragement of the rental sector through public policy should provide an alternative for low-income families. Despite different cultural housing backgrounds, the emergence of a reliable rental sector in Spain appears to be the most promising strategy for solving current housing problems. The aim of the paper is twofold. On the one hand, it analyses the evolution of the rental sector through recent decades, stressing how different central government regulations have affected the tenure structure in Spain. On the other, it considers the rental sector as a potential instrument for authorities to meet the housing needs of low-income families. Housing policy still plays a crucial role in offering the opportunity for certain groups to access a suitable house. What can be called the 'European shift' to the market can cause irreparable damage to those families that have benefited from former, direct or indirect, public means.
On the Genesis of Social Rental Agencies in Belgium
Authors: De Decker Pascal
Published: October 2002

A combination of historical housing policy options together with the housing consequences of the economic crisis and the changes in household structure led to a major housing crisis in Belgium during the 1980s. Since the Belgian government, hampered by severe budget constraints and the paralysing consequences of restructuring, was not able to deal with these new problems, grassroots organisations took the lead in formulating solutions—hence the so-called new housing initiatives, social rental agencies (SRAs) being the most important ones. Today, less than 20 years later, these social rental agencies are institutionalised and cover a large part of the country. This paper elaborates on the birth and rise of the SRAs first by looking at the causes of the housing crisis and secondly by analysing the grassroots reactions.
Marketing Mardi Gras: Commodification, Spectacle and the Political Economy of Tourism in New Orleans
Authors: Gotham Kevin Fox
Published: October 2002

Recent urban scholarship on the rise of the tourism industry, place marketing and the transformation of cities into entertainment destinations has been dominated by four major themes: the primacy of `consumption' over 'production'; the eclipse of exchange-value by sign-value; the idea of autoreferential culture; and, the ascendancy of textual deconstruction and discursive analyses over political economy critiques of capitalism. This paper critically assesses the merits of these four themes using a case study of the Mardi Gras celebration in New Orleans. The analytical tools and categories of political economy are used to examine the rise and dominance of tourism in New Orleans, explore the consequences of this economic shift and identify the key actors and organised interests involved in marketing Mardi Gras. 'Marketing' is the use of sophisticated advertising techniques aimed at promoting fantasy, manipulating consumer needs, producing desirable tourist experiences and simulating images of place to attract capital and consumers. The paper points to the limitations of the 'cultural turn' and the 'linguistic turn' in urban studies and uses the concepts of commodification and spectacle as a theoretical basis for understanding the marketing of cities, the globalisation of local celebrations and the political economy of tourism.
A Comparative Institutional Evaluation of Public-Private Partnerships in Dutch Urban Land-use and Revitalisation Projects
Authors: Nijkamp Peter , van der Burch Marc , Vindigni Gabriella
Published: October 2002

In the spirit of the devolution of public policy, we have recently witnessed an increasing popularity of decentralised forms of decision-making in urban land-use policy, in which both local (or regional) authorities and the private sector play a more prominent joint role in the preparation and implementation of urban development projects. The paper describes the pathway to a more institutional multi-actor mode of urban land-use and revitalisation projects within the framework of deregulated land markets and maps out various relevant aspects of competitive land use. In particular, an attempt is made to identify the crucial `drivers' of this complex decision-making process in an urban context, against the background of revitalisation objectives for modern cities. The literature suggests, in particular, that the institutional constellation, the financial viability and the presence of spatial externalities may act as critical factors for public-private partnerships. This proposition is tested in the paper by means of a comparative study on nine carefully selected urban development projects—more specifically, nine types of public-private partnerships—in The Netherlands. After the design of a systematic database on these projects, a particular type of qualitative fuzzy classification analysis originating from artificial intelligence, known as rough set analysis, is deployed to assess and identify the most important factors that are responsible for successes and failures of recent development plans in Dutch cities. This approach allows us to pinpoint the most critical policy variables.
'Scan Globally; Reinvent Locally': Reflecting on the Origins of South Africa's Capital Housing Subsidy Policy
Authors: Gilbert Alan
Published: October 2002

Perhaps in an ideal world, governments would learn from the experiences of others. What has worked well or badly in one place can be repeated or avoided in another. Of course, one place is different from another so that modifications to any policy are usually necessary. When South Africa adopted its new housing policy in 1994, there was a lot of experience around. However, despite the efforts of powerful institutions like the World Bank, it chose to ignore much of that experience. Arguably, six years later, it is about to adopt some of the advice it previously rejected. The paper considers why South Africa ignored experience elsewhere and how it managed to avoid pressure from the World Bank to accept housing policies that it felt were inappropriate to its needs. The lesson of this experience is ambiguous. It shows that governments often have their own agenda and that medium-sized, middle-income countries have considerable influence in their negotiations with 'developmental' Washington. On the other hand, by adopting a set of macroeconomic policies which were in accord with current orthodoxy, and the reduced housing budget that this policy implied, perhaps South Africa merely showed that there are much more powerful hegemonic forces operating than the World Bank.
Fiscalisation of Land Use, Urban Growth Boundaries and Non-central Retail Sprawl in the Western United States
Authors: Wassmer Robert W.
Published: October 2002

Do the ways that local governments raise own-source revenue and/or use urban growth boundaries exert distinct influences on the occurrence of retail activity outside a metropolitan area's central places? This question is addressed in this paper through a regression analysis that also accounts for economic factors that provide clear reasons for retail activity to locate in non-central places. Results indicate that state-wide reliance by municipalities on some forms of own-source revenue exert significant positive influences on retail sales in non-central places in metropolitan areas in the western US. 'Excessive' retail decentralisation generated through this 'fiscalisation of land use' is presented within the widely discussed concept of 'urban sprawl'. The continuing presence of one form of urban growth boundary is also found to reduce retail decentralisation.
In Search of Permanent Homes: Singapore's House Churches and the Politics of Space
Authors: Kong Lily
Published: October 2002

This paper focuses on one category of the 'unofficially sacred'-namely, those secular spaces which are used for worship and, in particular, residential spaces which are turned into 'house churches'. Using the case study of a house church in Singapore, the paper examines issues about the politics of religion in urban landscapes in a secular and simultaneously multireligious state. Contrary and in addition to current wisdoms about the politics of religious space, it is argued that various politics are observed: a politics of inclusion; a politics of hybridisation and in-betweenness; a politics of appropriation and nationalisation; and a politics of impermanence and precarity. Through this analysis, the paper seeks to bring added conceptual perspectives to the notion of 'sacred space' within the context of modern, urban, secular settings.
Human alcoholism studies of genes identified through mouse quantitative trait locus analysis
Authors: Ehringer Marissa A. , Thompson Jessica , Conroy Otakuye , Goldman David , Smith Tom L. , Schuckit Marc A. , Sikela James M.
Published: October 2002

Coding region DNA sequence variants have been recently identified in several QTL candidate genes in a mouse model of differential sensitivity to alcohol [inbred long‐sleep (ILS) and inbred short‐sleep (ISS)]. This work has been extended into a human population characterized for their initial level of response to alcohol (LR). The coding region of one of the most promising of these candidate genes, zinc finger 133 (Znf133), has been sequenced completely in 50 individuals who participated in alcohol challenges at approximately age 20 and have been followed subsequently for the last 15 years. PCR products were obtained for the protein coding region of ZNF133 using human genomic DNA and directly sequenced using automated sequencers. Novel single nucleotide polymorphisms (SNPs) were detected by analyzing the sequence data using a suite of bioinformatics programs including Consed, Phred, Phrap and Polyphred. Five human SNPs were detected, two that correspond to amino acid changes in the protein, two that are silent DNA changes and one located in an intron. In this small sample, no significant association between any of the SNPs and alcohol diagnosis was detected. A follow‐up of these SNPs in a larger sample should allow a more definitive conclusion to be reached. Significantly, the data presented here demonstrate the feasibility of directly testing genes in human alcoholic populations that had been identified first by comparative DNA sequencing of candidate genes located within mouse alcohol‐related QTLs, even without detailed knowledge of the gene's function.
Acupuncture in the treatment of alcohol withdrawal symptoms: a randomized, placebo‐controlled inpatient study
Authors: Karst Matthias , Passie Torsten , Friedrich Steffen , Wiese Birgitt , Schneider Udo
Published: October 2002

Thirty‐four alcoholics were treated with acupuncture to the ear and the body in a randomized single‐blind placebo‐controlled design over 14 days. Orthodox points and placebo needles to orthodox points were used daily for a total of 10 treatments starting on the first day of admission as add‐on therapy to standard medication with carbamazepine. The primary outcome was the Clinical Institute Withdrawal Assessment (CIWA‐Ar‐scale) assessed on days 1‐6, 9 and 14. No initial differences were found regarding sociodemographic data, drinking history and alcohol‐related data, indicating successful randomization. Longitudinal analysis of the Clinical Institute Withdrawal Assessment (CIWA‐Ar‐scale) data showed that patients assigned to acupuncture had a general tendency towards better outcome results and significantly fewer withdrawal symptoms on day 14 (Wilcoxon‐W=177.500, Z=‐2.009, p = 0.045). No significant differences were found in the Beck Depression Inventory (BDI), State‐Trait Anxiety Inventory (STAI X1 and X2) and Eigenschaftswoerterliste (EWL S60). We conclude that acupuncture as an adjunctive treatment to carbamazepine medication shows promise for the treatment of alcohol withdrawal symptoms. Further investigation of this treatment modality appears to be warranted.
Does paradoxical sleep deprivation and cocaine induce penile erection and ejaculation in old rats?
Authors: Andersen Monica L. , Bignotto Magda , Machado Ricardo Borges , Tufik Sergio
Published: October 2002

A recent study has established that paradoxical sleep deprivation (PSD) and cocaine administration elicit genital reflexes (penile erection and ejaculation) in young rats. To discover whether the same effects occurred in old animals submitted to PSD, we administered cocaine (15 mg/kg) to young (3‐month) and old (22‐month) male rats after a 4‐day period of PSD or at the equivalent time‐point in control animals. We then evaluated erections and ejaculations. Sixty per cent of the old‐PSD group displayed erection, although ejaculation was not observed. Genital reflexes were absent in young and old control groups. We found that PSD reduced testosterone and increased progesterone levels in both young and old PSD groups. In conclusion, our results suggest that although genital reflexes usually decrease with age, testosterone levels alone cannot account for these changes. The interaction of PSD and cocaine probably enhances dopamine transmission in the brain and may elicit penile erection in old rats.
Adjuvant Chemotherapy Following Complete Resection of Soft Tissue Sarcoma in Adults: A Clinical Practice Guideline
Authors: Figueredo Alvaro , Bramwell Vivien H. C. , Bell Robert , Davis Aileen M. , Charette Manya L. , The members of the cancer care Ontario practice guidelines i
Published: October 2002

Purpose. To review the literature and make recommendations for the use of anthracycline‐based adjuvant chemotherapy in adult patients with soft tissue sarcoma (STS).

Patients. The recommendations apply to patients >15 years old with completely resected STS.

Methods. A systematic overview of the published literature was combined with a consensus process around the interpretation of the evidence in the context of conventional practice to develop an evidence‐based practice guideline.

Results. Four meta‐analyses and 17 randomized clinical trials comparing anthracycline‐based adjuvant chemotherapy versus observation were reviewed. The Sarcoma Meta‐Analysis Collaboration (SMAC) was the best analysis because it assessed individual patient data and had the longest follow‐up. The results of the SMAC meta‐analysis together with data from more recently published randomized trials, as well as our analysis of the toxicity and compliance data, are incorporated in this systematic review.

Discussion. It is reasonable to consider anthracycline‐based adjuvant chemotherapy in patients who have had removal of a sarcoma with features predicting a high likelihood of relapse (deep location, size >5 cm, high histological grade). Although the benefits of adjuvant chemotherapy are most apparent in patients with extremity sarcomas, patients with high‐risk tumours at other sites should also be considered for such therapy.
Molecular Approaches to Sarcoma Therapy
Authors: Olsen R. J. , Tarantolo S. R. , Hinrichs S. H.
Published: October 2002

Soft tissue sarcomas comprise a heterogeneous group of aggressive tumors that have a relatively poor prognosis. Although
conventional therapeutic regimens can effectively cytoreduce the overall tumor mass, they fail to consistently achieve a
curative outcome. Alternative gene‐based approaches that counteract the underlying neoplastic process by eliminating
the clonal aberrations that potentiate malignant behavior have been proposed. As compared to the accumulation of gene
alterations associated with epithelial carcinomas, sarcomas are frequently characterized by the unique presence of a single
chromosomal translocation in each histological subtype. Similar to the Philadelphia chromosome associated with CML,
these clonal abnormalities result in the fusion of two independent unrelated genes to generate a unique chimeric protein
that displays aberrant activity believed to initiate cellular transformation. Secondary gene mutations may provide an additional
growth advantage that further contributes to malignant progression. The recent clinical success of the tyrosine kinase
inhibitor, STI571, suggests that therapeutic approaches specifically directed against essential survival factors in sarcoma cells
may be effective. This review summarizes published approaches targeting a specific molecular mechanism associated with
sarcomagenesis. The strategy and significance of published translational studies in six distinct areas are presented. These
include: (1) the disruption of chimeric transcription factor activity; (2) inhibition of growth stimulatory post‐translational
modifications; (3) restoration of tumor suppressor function; (4) interference with angiogenesis; (5) induction of apoptotic
pathways; and (6) introduction of toxic gene products. The potential for improving outcomes in sarcoma patients and the
conceptual obstacles to be overcome are discussed.
Identification and Confirmation of a Module of Coexpressed Genes
Authors: Thompson H. Garrett R. , Harris Joseph W. , Wold Barbara J. , Quake Stephen R. , Brody James P.
Published: October 2002

We synthesize a large gene expression data set using dbEST and UniGene. We use guilt-by-association (GBA) to analyze this data set and identify coexpressed genes. One module, or group of genes, was found to be coexpressed mainly in tissue extracted from breast and ovarian cancers, but also found in tissue from lung cancers, brain cancers, and bone marrow. This module contains at least six members that are believed to be involved in either transcritional regulation (PDEF, H2AFO, NUCKS) or the ubiquitin proteasome pathway (PSMD7, SQSTM1, FLJ10111). We confirm these observations of coexpression by real-time RT–PCR analysis of mRNA extracted from four model breast epithelial cell lines.
Acoustic diffraction by a half-plane in a viscous fluid medium
Authors: Davis Anthony M. J. , Nagem Raymond J.
Published: October 2002

We consider the diffraction of a time-harmonic acoustic plane wave by a rigid half-plane in a viscous fluid medium. The linearized equations of viscous fluid flow and the no-slip condition on the half-plane are used to derive a pair of disjoint Wiener–Hopf equations for the fluid stresses and velocities. The Wiener–Hopf equations are solved in conjunction with a requirement that the stresses are integrable near the edge of the half-plane. Specific wave components of the scattered velocity field are given analytically. A Padé approximation to the Wiener–Hopf kernel function is used to derive numerical results that show the effect of viscosity on the velocity field in the immediate vicinity of the edge of the half-plane.
A functional equation for the specular reflection of rays
Authors: Le Bot A.
Published: October 2002

This paper aims to generalize the “radiosity method” when applied to specular reflection. Within the field of thermics, the radiosity method is also called the “standard procedure.” The integral equation for incident energy, which is usually derived for diffuse reflection, is replaced by a more appropriate functional equation. The latter is used to solve some specific problems and it is shown that all the classical features of specular reflection, for example, the existence of image sources, are embodied within this equation. This equation can be solved with the ray-tracing technique, despite the implemented mathematics being quite different. Several interesting features of the energy field are presented.
Geoacoustic inversion of ambient noise: A simple method
Authors: Harrison C. H. , Simons D. G.
Published: October 2002

The vertical directionality of ambient noise is strongly influenced by seabed reflections. Therefore, potentially, geoacoustic parameters can be inferred by inversion of the noise. In this approach, using vertical array measurements, the reflection loss is found directly by comparing the upward- with the downward-going noise. Theory suggests that this simple ratio is, in fact, the power reflection coefficient—potentially a function of angle and frequency. Modeling and parameter searching are minimized, and the method does not require a detailed knowledge of the noise source distribution. The approach can handle stratified environments and is believed to tolerate range dependence. Experimental data from five sites, four in the Mediterranean, one on the New Jersey Shelf, are described. Most of the Mediterranean sites had temporally varying noise directionality, yet yielded the same reflection properties, as one would hope. One site was visited in conditions of very low surface noise. This paper concentrates on an experimental demonstration of the feasibility of the method and data quality issues rather than automatic search techniques for geoacoustic parameters.
Automatic transformation of series expressions into loops
Authors: Waters Richard C.
Published: October 2002

The benefits of programming in a functional style are well known. In particular, algorithms that are expressed as compositions of functions operating on sequences/vectors/streams of data elements are easier to understand and modify than equivalent algorithms expressed as loops. Unfortunately, this kind of expression is not used anywhere near as often as it could be, for at least three reasons: (1) most programmers are less familiar with this kind of expression than with loops; (2) most programming languages provide poor support for this kind of expression; and (3) when support is provided, it is seldom effcient.

In any programming language, the second and third problems can be largely solved by introducing a data type called
series
, a comprehensive set of procedures operating on series, and a preprocessor (or compiler extension) that automatically converts most series expressions into efficient loops. A set of restrictions specifies which series expressions can be optimized. If programmers stay within the limits imposed, they are guaranteed of high efficiency at all times.

A common Lisp macro package supporting series has been in use for some time. A prototype demonnstrates that series can be straightforwardly supported in Pascal.
Cache behavior of combinator graph reduction
Authors: Koopman Philip J. , Lee Peter , Siewiorek Daniel P.
Published: October 2002

The results of cache-simulation experiments with an abstract machine for reducing combinator graphs are presented. The abstract machine, called TIGRE, exhibits reduction rates that, for similar kinds of combinator graphs on similar kinds of hardware, compare favorably with previously reported techniques. Furthermore, TIGRE maps easily and efficiently onto standard computer architectures, particularly those that allow a restricted form of self-modifying code. This provides some indication that the conventional "stored program" organization of computer systems is not necessarily an inappropriate one for functional programming language implementations.

This is not to say, however, that present day computer systems are well equipped to reduce combinator graphs. In particular, the behavior of the cache memory has a significant effect on performance. In order to study and quantify this effect, trace-driven cache simulations of a TIGRE graph reducer running on a reduced instruction-set computer are conducted. The results of these simulations are presented with the following hardware-cache parameters varied: cache size, block size, associativity, memory update policy, and write-allocation policy. To begin with, the cache organization of a commercially available system is used and then the performance sensitivity with respect to variations of each parameter are measured. From the results of the simulation study, a conclusion is made that combinator-graph reduction using TIGRE runs most efficiently when using a cache memory with an allocate-on-write-miss strategy, moderately large block size (preferably with subblock placement), and copy-back memory updates.
The CLP( ℛ ) language and system
Authors: Jaffar Joxan , Michaylov Spiro , Stuckey Peter J. , Yap Roland H. C.
Published: October 2002

The CLP( ℛ ) programming language is defined, its underlying philosophy and programming methodology are discussed, important implementation issues are explored in detail, and finally, a prototype interpreter is described.

CLP( ℛ ) is designed to be an instance of the Constraint Logic Programming Scheme, a family of rule-based constraint programming languages defined by Jaffar and Lassez. The domain of computation ℛ of this particular instance is the algebraic structure consisting of uninterpreted functors over real numbers. An important property of CLP( ℛ )is that the constraints are treated uniformly in the sense that they are used to specify the input parameters to a program, they are the only primitives used in the execution of a program, and they are used to describe the output of a program.

Implementation of a CLP language, and of CLP( ℛ ) in particular, raises new problems in the design of a constraint-solver. For example, the constraint solver must be
incremental
in the sense that solving additional constraints must not entail the resolving of old constraints. In our system, constraints are filtered through an inference engine, an engine/solver interface, an equation solver and an inequality solver. This sequence of modules reflects a classification and prioritization of the classes of constraints. Modules solving higher priority constraints are isolated from the complexities of modules solving lower priority constraints. This multiple-phase solving of constraints, together with a set of associated algorithms, gives rise to a practical system.
A methodology for implementing highly concurrent data objects
Authors: Herlihy Maurice
Published: October 2002

A
concurrent object
is a data structure shared by concurrent processes. Conventional techniques for implementing concurrent objects typically rely on
critical sections
; ensuring that only one process at a time can operate on the object. Nevertheless, critical sections are poorly suited for asynchronous systems: if one process is halted or delayed in a critical section, other, nonfaulty processes will be unable to progress. By contrast, a concurrent object implementation is
lock free
if it always guarantees that some process will complete an operation in a finite number of steps, and it is
wait free
if it guarantees that
each
process will complete an operation in a finite number of steps. This paper proposes a new methodology for constructing lock-free and wait-free implementations of concurrent objects. The object's representation and operations are written as stylized sequential programs, with no explicit synchronization. Each sequential operation is atutomatically transformed into a lock-free or wait-free operation using novel synchronization and memory management algorithms. These algorithms are presented for a multiple instruction/multiple data (MIMD) architecture in which
n
processes communicate by applying atomic
read, write, load_linked,
and
store_conditional
operations to a shared memory.
Suspension analyses for concurrent logic programs
Authors: Codish Michael , Falaschi Moreno , Marriott Kim
Published: October 2002

Concurrent logic languages specify reactive systems which consist of collections of communicating processes. The presence of unintended suspended computations is a common programming error which is difficult to detect using standard debugging and testing techniques. We develop a number of analyses, based on abstract interpretation, which succeed if a program is definitely suspension free. If an analysis fails, the program may, or may not, be suspension free. Examples demonstrate that the analyses are practically useful. They are conceptually simple and easy to justify because they are based directly on the transition system semantics of concurrent logic programs. A naive analysis must consider
all scheduling policies
. However, it is proven that for our analyses it suffices to consider only
one
scheduling policy, allowing for efficient implementation.