bluuebunny/crossref_metadata_2025 huggingface dataset:
An efficient real‐time method of analysis for non‐coherent fault trees
Authors: Remenyte‐Prescott Rasa , Andrews John D.
Published: August 2008

Fault tree analysis is commonly used to assess the reliability of potentially hazardous industrial systems. The type of logic is usually restricted to AND and OR gates, which makes the fault tree structure coherent. In non‐coherent structures not only components' failures but also components' working states contribute to the failure of the system. The qualitative and quantitative analyses of such fault trees can present additional difficulties when compared with the coherent versions. It is shown that the binary decision diagram (BDD) method can overcome some of the difficulties in the analysis of non‐coherent fault trees. This paper presents the conversion process of non‐coherent fault trees to BDDs. A fault tree is converted to a BDD that represents the system structure function (SFBDD). An SFBDD can then be used to quantify the system failure parameters but is not suitable for the qualitative analysis. Established methods, such as the meta‐products BDD method, the zero‐suppressed BDD (ZBDD) method and the labelled BDD (L‐BDD) method, require an additional BDD that contains all prime implicant sets. The process using some of the methods can be time consuming and is not very efficient. In addition, in real‐time applications the conversion process is less important and the requirement is to provide an efficient analysis. Recent uses of the BDD method are for real‐time system prognosis. In such situations as events happen, or failures occur, the prediction of mission success is updated and used in the decision‐making process. Both qualitative and quantitative assessments are required for the decision making. Under these conditions fast processing and small storage requirements are essential. Fast processing is a feature of the BDD method. It would be advantageous if a single BDD structure could be used for both the qualitative and quantitative analyses. Therefore, a new method, the ternary decision diagram (TDD) method, is presented in this paper, where a fault tree is converted to a TDD that allows both qualitative and quantitative analyses and no additional BDDs are required. The efficiency of the four methods is compared using an example fault tree library. Copyright © 2008 John Wiley & Sons, Ltd.
Discrete sets of many‐body Sturmians
Authors: Randazzo J. M. , Frapiccini A. L. , Colavecchia F. D. , Gasaneo G.
Published: August 2008

In this work, we present a method to obtain two‐particle Coulomb Sturmians Functions (CSF) with an expansion in a set of L2 basis functions. In the two‐body case, we recover the exact (discrete) spectrum of the CSFs for negative energies and a discretized approximation for positive ones. Besides, we make use of this method to analyze the two‐independent electron problem as a Generalized Sturmian problem. We propose a discretized version of the wave function in terms of the CSF states, and show that the problem reduces to find numerical coincidences between energy‐dependent eigencharges of the mutually independent one‐electron systems. This expansion methodology includes the continuum information which is lost in the sets used previously in the literature, and is complete when the size of the basis goes to infinity. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
New approach for the correction of Ab initio molecular force fields in cartesian coordinates
Authors: Kochikov I. V. , Kuramshina G. M. , Stepanova A. V.
Published: August 2008

This paper presents a scaling technique applicable to molecular force constants in Cartesian coordinates. In the course of spectroscopic and structural research, it is a common practice to achieve better correspondence between measured and calculated vibrational frequencies of a molecule by appropriate scaling of the force constant matrices obtained by quantum chemical methods. However, the existing scaling procedure requires introduction of the complete system of internal coordinates, which may be tedious and time‐consuming for complex molecules. Scaling scheme suggested in this paper is applied directly to Cartesian force constant matrices and thus does not require introduction of the internal coordinates. Practical implementation of the proposed approach is illustrated with the examples of simple molecules. The scheme allows imposing special constraints on the determined Cartesian scale factors, which may be used for obtaining scale factors possessing transferability properties. These properties are very important for vibrational spectra calculations of related compounds, especially for large biological molecules, associates and nanostructures. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Convergence of the binding energy of oxygen on Cu(100): A cautionary tale for computational chemists using periodic bound conditions
Authors: Bauschlicher Charles W.
Published: August 2008

The convergence of the binding energy of oxygen on Cu(100) as a function of the k‐points, energy cutoff for the inclusion of plane waves, surface model, and oxygen coverage is studied. Overall the convergence is good, with an accuracy of 0.1 eV obtained for an affordable level of treatment. Published 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Theoretical analysis of vibrational spectra and scaling‐factor of 2‐aryl‐1,3,4‐oxadiazole derivatives
Authors: Avci Davut , Atalay Yusuf
Published: August 2008

In this study, the direct molecular structure implementations for calculating vibrational spectra and scaling factors, and infrared intensities at both the Hartree–Fock (HF) and density functional (B3LYP) levels of theory with 6‐31G(d), 6‐311G(d), 6‐31++G(d,p), and 6‐311++G(d,p) basis sets are presented. Also, vibrational frequencies have been investigated as dependence on the choice of method and basis set. The parameters of molecular geometry and vibrational frequencies values of 2‐aryl‐1,3,4‐oxadiazoles 5a–g in the ground state have been calculated. Theoretical determination of vibrational frequencies is quite useful both in understanding the relationship between the molecular structures and scaling factor. The data of 2‐aryl‐1,3,4‐oxadiazoles 5a–g display significant electronic properties provide the basis for future design of efficient materials having the oxadiazole core and theoretical IR studies. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Investigations on spectroscopic properties of ND(X3Σ−) radical using coupled‐cluster theory in combination with the correlation‐consistent quintuple basis set augmented with diffuse functions
Authors: Shi De‐Heng , Yu Ben‐Hai , Zhang Jin‐Ping , Liu Yu‐Fang , Zhu Zheng‐He
Published: August 2008

The coupled‐cluster singles‐doubles‐approximate‐triples [CCSD(T)] theory in combination with the correlation‐consistent quintuple basis set augmented with diffuse functions (aug‐cc‐pV5Z) is used to investigate the spectroscopic properties of the ND(X3Σ−) radical. The adiabatic potential energy curve is calculated over the internuclear separation range from 0.06 to 2.47 nm and fitted to the analytic Murrell–Sorbie function, which is used to determine the spectroscopic parameters, ωeχe, αe, and Be. The present De, Re, ωe, ωeχe, αe, and Be values are of 3.57357 eV, 0.10367 nm, 2403.166 cm−1, 42.888 cm−1, 0.25344 cm−1, and 8.90867 cm−1, respectively, which are in excellent agreement with the available measurements. With the potential obtained at the UCCSD(T)/aug‐cc‐pV5Z level of theory, a total of 21 vibrational states is predicted when J = 0 by numerically solving the radial Schrödinger equation of nuclear motion. The complete vibrational levels, classical turning points, inertial rotation, and centrifugal distortion constants are reproduced for the ND(X3Σ−) radical when J = 0 for the first time, which are in good accord with the available RKR data. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Characterization of optical spectra of interacting systems: Application to oxide‐supported metal clusters
Authors: Huix‐Rotllant Miquel , Deka Ajanta , Matveev Alexei V. , Bosko Sergey I. , Moskaleva Lyudmila V. , Rösch Notker
Published: August 2008

We present a general strategy for interpreting optical spectra of interacting systems on the basis of linear‐response time‐dependent density functional theory (TDDFT) calculations. For this purpose, we combined a natural transition orbitals (NTO) analysis with a fragment molecular orbital (FMO) analysis. The NTO transformation allows one to identify leading contributions of particle‐hole excitations in the spectral bands, whereas the FMO analysis characterizes each pair in terms of (leading) contributions of the corresponding fragments. We applied this procedure to assign and characterize optical transitions of coinage metal dimers M2 (M = Cu, Ag, Au) adsorbed at regular oxygen sites of MgO(001) as well as at oxygen vacancies, Fs and F. The TDDFT calculations were carried out at the generalized‐gradient level on structures that had been obtained with cluster models embedded in an elastic polarizable environment. The combined NTO and FMO results allowed us to analyze the spectra both qualitatively and quantitatively. The qualitative results agree very well with a previous assignment carried out by our group (Bosko et al., J Phys Chem A, 2007, 111, 6870), whereas the present approach yields a straightforward and transparent quantitative characterization of the main spectral bands. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Mental health and its relationship to life events and family socio‐economic status among Chinese medical students in Guangxi Zhuang Autonomous Region
Authors: Ma Yingjiao , Goto Aya , Yasumura Seiji , Wu Qijun , Xu Jianguo
Published: August 2008

The aim of the study was to investigate the mental health status of Chinese medical students in response to dramatic changes in their society and to assess its relationship to life events and family socio‐economic status (SES). This was a cross‐sectional study of 568 second year medical students in Guangxi Zhuang Autonomous Region. They completed the Symptom Checklist‐90‐Revised (SCL‐90‐R) to assess their mental health status, Adolescent Self‐Rating Life Events Check List (ASLEC), family SES items and parental divorce. A total of 552 students (262 males and 290 females) completed the questionnaires. The means of six SCL‐90‐R scales were significantly lower than the previously reported data on Chinese university students. Scores on four subscales were significantly higher for male compared with female students. Multivariate regression analysis indicated that the occupation and education of the fathers of female students were significantly associated with the summary index of SCL‐90‐R (General Symptomatic Index or GSI) and also with ASLEC scores. For male students, only the relationship with ASLEC scores was statistically significant. Seven of 27 life events measured by the ASLEC were significantly associated with GSI for males, and nine events were associated with GSI for females. The events were related to family financial status, academic stress and interpersonal relationships for both genders. In conclusion, our data underscore the importance of considering family history in addition to academic stressors, interpersonal relationships and gender differences, in attempts to secure the psychological well‐being of Chinese medical students. Copyright © 2008 John Wiley & Sons, Ltd.
Characterization of aerosol particles at an industrial background site in Nairobi, Kenya
Authors: Gatari Michael J. , Boman Johan , Wagner Annemarie
Published: August 2008

Air pollutants from industrial and urban sources contain harmful elements and chemical compounds. This work presents a study on background industrial and urban aerosol particles in the city of Nairobi. Its main focus was the understanding of elemental, black carbon (BC) and particulate mass (PM) concentrations in the perspective of identifying their sources. Aerosol particles were collected on Teflon filters in two size fractions, a fine fraction of particles having an aerodynamic diameter (da) < 2.5 µm and a coarse fraction with particles between 2.5 and 10 µm. A photometer and an energy dispersive x‐ray fluorescence spectrometer were used to analyse BC and trace elements (Si, S, Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr and Pb), respectively. The sampled mass of the particulate matter was determined gravimetrically. The measured concentrations of the analysable species were dominated by BC, K and S in the fine fraction and Si, Ca and Fe in the coarse fraction. Principal component analysis and correlation evaluation of the fine fraction concentrations implicated industrial, vehicular and biomass‐burning emissions as the main sources of the measured elements. The average Pb concentration of 105 ng m−3 in the PM10 samples at the background industrial site was approximately 20% of the air quality guideline (AQG) recommended by World Health Organisation (WHO). Most of the measured elements exhibited higher concentrations than those measured in Francistown in Botswana, Dar es Salaam in Tanzania and Edinburgh in United Kingdom but less than those measured in Barcelona in Spain and from previous studies in Nairobi. Copyright © 2008 John Wiley & Sons, Ltd.
Elemental depth profile of faux bamboo paint in Forbidden City studied by synchrotron radiation confocal µ‐XRF
Authors: Wei Xiangjun , Lei Yong , Sun Tianxi , Lin Xiaoyan , Xu Qing , Chen Dongliang , Zou Yang , Jiang Zheng , Huang Yuying , Yu Xiaohan , Ding Xunliang , Xu Hongjie
Published: August 2008

A three‐dimensional (3D) analysis of micro x‐ray fluorescence (XRF), namely confocal µ‐XRF, has been constructed at 4W1B beamline of the Beijing synchrotron radiation facility (BSRF). A KB mirror is applied to focus the incident beam and a polycapillary half‐lens in front of the Si(Li) detector is used to limit the visual field of the detector. The faux bamboo paint in Emperor Qianlong's Lodge of Retirement in Forbidden City was analyzed nondestructively by this method. A stratified structure in the paint is disclosed and the results show that the painting was probably restored once in the past, following the same painting technique as originally used. Copyright © 2008 John Wiley & Sons, Ltd.
Composition determination for complex and transmitting samples in x‐ray quantitative analysis
Authors: Vasquez R. P.
Published: August 2008

In this work, quantitative analysis of x‐ray fluorescence measurements of transmitting samples with complex chemical composition is considered. A method is presented for analytical solution of sample composition including matrix effects, independent of sample thickness and requiring no standards. The method uses fundamental parameters and measured fluorescence signal intensities, and is applicable to transmission geometry measurements for which standard analyses are not applicable. Limitations of the analysis presented here are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Bead‐releasing agents used in the preparation of solid samples as beads for WD‐XRF measurement
Authors: Gazulla M. F. , Barba A. , Orduña M. , Rodrigo M.
Published: August 2008

This paper carries the results of an evaluation of various materials, which may be used to aid in the release of a fused bead from its mould during a wavelength‐dispersive x‐ray fluorescence (WD‐XRF) measurement.

The following bead‐releasing agents were studied: NaI, LiBr, NH4I, and LiI. Each was incorporated in different quantities, as a solid and/or in an aqueous solution, together with a flux, into samples of ceramic raw materials. Release agent interference in the WD‐XRF measurement was analysed, and the optimum quantity of release agent needed to obtain suitable beads for WD‐XRF measurement was determined.

The best results were obtained for LiI, which yielded reproducible beads without significant interference in the WD‐XRF measurement when a relatively small quantity (0.11 LiI g/bead) was used. Copyright © 2008 John Wiley & Sons, Ltd.
The Relevance of Rice
Authors: Zeigler Robert S. , Barclay Adam
Published: August 2008

Research into rice—the world’s most important food crop—is crucial for the development of technologies that will increase productivity for farmers who rely on rice for their livelihood. This is particularly the case throughout the developing countries of Asia and is also true for much of Latin America and, increasingly, Africa. The benefits of such increased productivity will flow through to rice-growing countries’ landless rural and urban poor, all of whom (1) are net consumers of rice and (2) spend a large proportion of their income on rice. Recent steep rises in the price of rice have amplified the need for investment in high-quality research targeted toward both the intensive irrigated rice-based systems (in which 75% of the world’s rice is grown and that must provide the rice for rapidly increasing urban populations) and the rainfed rice-based systems (many of which are characterized by unfavorable environments and extreme poverty).
Rapid and Differential Proliferation of the Ty3-Gypsy LTR Retrotransposon Atlantys in the Genus Oryza
Authors: Zuccolo Andrea , Ammiraju Jetty S. S. , Kim HyeRan , Sanyal Abhijit , Jackson Scott , Wing Rod A.
Published: August 2008

Here, we present the results of a comprehensive study of the distribution, evolution, heterogeneity, and phylogenetic relationships of the Ty3-Gypsy Atlantys long terminal repeat retrotransposable element family in Oryza. Atlantys element-related sequences make up a significant fraction of the genomes of species from the Officinalis complex as well as the Oryza ridleyi and O. granulata genomes. The proliferation of Atlantys elements, in many cases, took place after respective speciation events occurred. Most of the retrotranspositional events occurred within the last three million years. Atlantys is an ancient and ubiquitous component of the genus Oryza and has made significant contributions to genome size variation across the genus. Its structure is unusual when compared to other Ty3-Gypsy elements and its proliferation in the different Oryza species has been rapid and differential.
A note on constant geodesic curvature curves on surfaces
Authors: Sun Taoniu
Published: August 2008

In this paper we are concerned with the structure of curves on surfaces whose geodesic curvature is a large constant. We first discuss the relation between closed curves with large constant geodesic curvature and the critical points of Gauss curvature. Then, we consider the case where a curve with large constant geodesic curvature is immersed in a domain which does not contain any critical point of the Gauss curvature.

Dans cet article nous nous intéressons au comportement des courbes sur une surface, dont la courbure géodésique est une constante très grande. Dans un premier temps nous nous intéressons aux relations entre les courbes fermées dont la courbure géodésique est grande et les points critiques de la courbure de Gauss. Ensuite, nous nous intéressons au comportement asymptotique des courbes immergées dans un domaine de la surface qui ne contient aucun point critique de la courbure de Gauss.
Melatonin and roentgen irradiation‐induced acute radiation enteritis in Albino rats: An animal model
Authors: Hussein Mahmoud R. , Abu‐Dief Eman E. , Kamel Esam , El‐Ghait Amal T. Abou , Abdulwahed Saad Rezk , Ahmad Mohamed H.
Published: August 2008

Background: Roentgen irradiation can affect normal cells, especially the rapidly growing ones such as the mucosal epithelial cells of the small intestine. The small intestine is the most radiosensitive gastrointestinal organ and patients receiving radiotherapy directed to the abdomen or pelvis may develop radiation enteritis. Although roentgen rays are widely used for both imaging and therapeutic purposes, our knowledge about the morphological changes associated with radiation enteritis is lacking.

Hypothesis: This study tries to tests the hypothesis that “the intake of melatonin can minimize the morphological features of cell damage associated with radiation enteritis”.

Objectives and methods: We performed this investigation to test our hypothesis and to examine the possible radioprotective effects of melatonin in acute radiation enteritis. To achieve these goals, an animal model consisting of 60 Albino rats was established. The animals were divided into five groups: Group 1, non‐irradiated; Group 2, X‐ray irradiated (X‐ray irradiation, 8 Grays); Group 3, X‐ray irradiated‐pretreated with solvent (ethanol and phosphate buffered saline); Group 4, non‐irradiated‐group treated with melatonin, and Group 5, X‐ray irradiated‐pretreated with melatonin. The small intestines were evaluated for gross (macroscopic), histological, morphometric (light microscopy), and ultrastructural changes (transmission electron microscopy).

Results: We found morphological variations among the non‐irradiated‐group, X‐ray irradiated‐group and X‐ray irradiated‐intestines of the animals pretreated with melatonin. The development of acute radiation enteritis in X‐ray irradiated‐group (Groups 2 and 3) was associated with symptoms of enteritis (diarrhea and abdominal distention) and histological features of mucosal injury (mucosal ulceration, necrosis of the epithelial cells). There was a significant reduction of the morphometric parameters (villous count, villous height, crypt height and villous/crypt height ratio). Moreover, the ultrastructural features of cell damage were evident including: apoptosis, lack of parallel arrangement of the microvilli, loss of the covering glycocalyx, desquamation of the microvilli, vacuolation of the apical parts of the cells, dilatation of the rough endoplasmic reticulum, and damage of the mitochondrial cristae. In the non‐irradiated‐group and in X‐ray irradiated‐intestines of the animals pretreated with melatonin (Group 5), these changes were absent and the intestinal mucosal structure was preserved.

Conclusion: Administration of melatonin prior to irradiation can protect the intestine against X‐rays destructive effects, i.e. radiation enteritis. The clinical applications of these observations await further studies.
Detection of infectious prions in urine
Authors: Gonzalez-Romero Dennisse , Barria Marcelo A. , Leon Patricia , Morales Rodrigo , Soto Claudio
Published: August 2008

Prions are the infectious agents responsible for prion diseases, which appear to be composed exclusively by the misfolded prion protein (PrPSc). The mechanism of prion transmission is unknown. In this study, we attempted to detect prions in urine of experimentally infected animals. PrPSc was detected in ∼80% of the animals studied, whereas no false positives were observed among the control animals. Semi‐quantitative calculations suggest that PrPSc concentration in urine is around 10‐fold lower than in blood. Interestingly, PrPSc present in urine maintains its infectious properties. Our data indicate that low quantities of infectious prions are excreted in the urine. These findings suggest that urine is a possible source of prion transmission.
GENERATING SYSTEMS OF SUBGROUPS IN PSL(2,Γn)
Authors: Wang Xiantao , Yang Weiqi
Published: August 2008

It is proved in this paper that for any non-elementary subgroup $G$ of $\mathrm{PSL}(2,\sGa_n)$, which has no elliptic element, to be not strict, there is a minimal generating system of $G$ consisting of loxodromic elements, and that if $G$ is a non-elementary subgroup of $\mathrm{PSL}(2,\sGa_n)$ of which each loxodromic element is hyperbolic, then $G$ is conjugate to a subgroup of $\mathrm{PSL}(2,\mathbb{R})$.

AMS 2000 Mathematics subject classification: Primary 30F40. Secondary 20H10
FAMILIES OF SURFACES IN ℝ4
Authors: Bruce J. W. , Tari F.
Published: August 2008

We study the geometry of surfaces in $\mathbb{R}^4$ associated to contact with hyperplanes. We list all possible transitions that occur on the parabolic and so-called $A_3$-set, and analyse the configurations of the asymptotic curves and their bifurcations in generic one-parameter families.

AMS 2000 Mathematics subject classification: Primary 58C27. Secondary 53A05
ON THE EINSTEIN–KÄHLER METRIC AND THE HOLONOMY OF A LINE BUNDLE
Authors: Tsuboi Kenji
Published: August 2008

In this paper we give a relation between the Futaki invariant for a compact complex manifold $M$ and the holonomy of a determinant line bundle over a loop in the base space of any principal $G$-bundle, where $G$ is the identity component of the maximal compact subgroup of the complex Lie group consisting of all biholomorphic automorphisms of $M$. Using the property of the Futaki invariant, we show that the holonomy is an obstruction to the existence of the Einstein–Kähler metrics on $M$. Our main result is Theorem 2.1.

AMS 2000 Mathematics subject classification: Primary 32Q20. Secondary 58J28; 58J52
ZETA FUNCTIONS OF GROUPS: EULER PRODUCTS AND SOLUBLE GROUPS
Authors: du Sautoy Marcus
Published: August 2008

The well-behaved Sylow theory for soluble groups is exploited to prove an Euler product for zeta functions counting certain subgroups in pro-soluble groups. This generalizes a result of Grunewald, Segal and Smith for nilpotent groups.

AMS 2000 Mathematics subject classification: Primary 20F16; 11M99
SOFT C*-ALGEBRAS
Authors: Farsi Carla
Published: August 2008

In this paper we consider soft group and crossed product $C^*$-algebras. In particular we show that soft crossed product $C^*$-algebras are isomorphic to classical crossed product $C^*$-algebras. We also prove that large classes of soft $C^*$-algebras have stable rank equal to infinity.

AMS 2000 Mathematics subject classification: Primary 46L80; 46L55
A NOTE ON INTEGERS OF THE FORM 2n+cp
Authors: Sun Zhi-Wei , Yang Si-Man
Published: August 2008

In 1950 Erdös proved that if $x\equiv2\,036\,812\ (\mo5\,592\,405)$ and $x\equiv3\ (\mo62)$, then $x$ is not of the form $2^n+p$, where $n$ is a non-negative integer and $p$ is a prime. In this note we present a theorem on integers of the form $2^n+cp$, in particular we completely determine all those integers $c$ relatively prime to $5\,592\,405$ such that the residue class $2\,036\,812(\mo5\,592\,405)$ contains integers of the form $2^n+cp$.

AMS 2000 Mathematics subject classification: Primary 11P32. Secondary 11A07; 11B25; 11B75
THE SUBRING OF GROUP COHOMOLOGY CONSTRUCTED BY PERMUTATION REPRESENTATIONS
Authors: Green David J. , Leary Ian J. , Schuster Björn
Published: August 2008

Each permutation representation of a finite group $G$ can be used to pull cohomology classes back from a symmetric group to $G$. We study the ring generated by all classes that arise in this fashion, describing its variety in terms of the subgroup structure of $G$.

We also investigate the effect of restricting to special types of permutation representations, such as $\mathrm{GL}_n(\mathbb{F}_p)$ acting on flags of subspaces.

AMS 2000 Mathematics subject classification: Primary 20J06
Rheology of the gel formed in the California Mastitis Test
Authors: Verbeek C Johan R , Xia Stephen S , Whyte David
Published: August 2008

The California Mastitis Test has previously been adapted for use in an inline, cow-side sensor and relies on the fact that the viscosity of the gel formed during the test is proportional to the somatic cell concentration. In this paper, the use of capillary and rotational viscometry was compared in light of the expected rheology of the gel formed during the test. It was found that the gel is non-Newtonian, but the initial phase of viscosity increase was not due to shear dependence, but rather due to the gelation reaction. The maximum apparent viscosity of the gel was shear dependent while the time it took to reach the maximum was not truly shear dependent, but was rather dependent on the degree of mixing during gelation. This was confirmed by introducing a delay time prior to viscosity measurement, in both capillary and rotational viscometry. It was found that by mixing the reagent and infected milk, then delaying viscosity measurement for 30 s, shortened the time it took to reach maximum viscosity by more than 60 s. The maximum apparent viscosity, however, was unaffected. It was found that capillary viscometry worked well to correlate relative viscosity with somatic cell count, but that it was sensitive to the reagent concentration. It can therefore be deduced that the rheology of the gel is complicated not only by it being non-Newtonian, but also by the strong dependence on test conditions. These make designing a successful sensor much more challenging.
On heating milk, the dissociation of κ-casein from the casein micelles can precede interactions with the denatured whey proteins
Authors: Anema Skelte G
Published: August 2008

When κ-casein (κ-CN) was added to milk, and the milk was subsequently pH adjusted (pH 6·5−6·9) and heated (90°C/15 min), the serum contained considerably higher levels of denatured whey proteins than the milks without added κ-CN. When milk at pH 6·5−6·9 was heated at 90°C for different times, κ-CN was found in the serum in the early stages of heating and before significant levels of whey proteins were denatured. κ-CN reached its maximum level in the serum before the whey proteins were fully denatured. When milk at pH 6·5−6·9 was heated at 20−90°C for 15 min, κ-CN dissociated from the casein micelles at all temperatures, with the level in the serum increasing with the temperature and the pH at heating. κ-CN dissociated from the micelles at temperatures below those at which significant levels of the whey proteins were denatured. When taken together, the results from these experiments strongly indicate that the dissociation of κ-CN from the micelles can precede the interaction of the denatured whey proteins with κ-CN, and that there is a preferential interaction of the denatured whey proteins with serum-phase κ-CN.
Putting privatisation into practice: the case of Zambia Consolidated Copper Mines Limited
Authors: Craig John
Published: August 2008

During the 1990s, African governments sought to translate their commitment to privatise state enterprises into action. In doing so, they faced questions concerning the form in which these enterprises would be sold, to whom and on what terms. This paper examines the privatisation of Zambia Consolidated Copper Mines (ZCCM) between 1992 and 2000. It argues that the capacity of the Zambian government to determine the answers to these questions was constrained by a number of factors, of which the most important were the strategies pursued by potential purchasers, the demands of donors and the financial weakness of ZCCM itself.
Donors, dictators and democrats in Africa
Authors: Goldsmith Arthur A.
Published: August 2008

African countries are among those receiving the most foreign aid per capita. Many detractors blame that aid for encouraging dictatorship and undermining democracy. This article takes a contrary view. It analyses the relationship between the amount of development assistance given to sub-Saharan countries in the 1990s, and changes in their political systems. There is empirical evidence that arbitrary, unrepresentative government diminished in Africa. The data also suggest a positive, though small, correlation between development assistance and democratisation in the 1990s. The issue now facing many African countries is how to consolidate and extend these reforms on their own, with less external support.
European public opinion and aid to Africa: is there a link?
Authors: Rye Olsen Gorm
Published: August 2008

The current international debate on aid to Africa seems to assume that public opinion matters, i.e. it presupposes the existence of a ‘bottom-up’ relationship between public opinion and aid policy. This paper shows that it is rather the other way round. It is only possible to understand the relationship between decision-making on aid and public opinion as a ‘top-down’ relationship. The conclusion is supported by case studies of five European aid donors: France, the UK, Germany, Denmark and the European Union. The ‘missing link’ between opinion and policy-making is mainly to be explained by the high degree of centralisation of decision-making and the weak link between government and society in this particular policy field. On the other hand, opinion surveys show that there are strong popular sentiments in Europe in favour of ‘helping the poor’. Also, surveys indicate that European public opinion believes that emergency assistance basically is the rationale for development aid. The humanitarian attitudes in favour of ‘helping the poor’ find an outlet in the growing amount of emergency assistance going to Africa, thus leaving decision-making on development aid to the elite in a typical top-down way.
Rwanda's Imidugudu programme and earlier experiences with villagisation and resettlement in East Africa
Authors: van Leeuwen Mathijs
Published: August 2008

Despite earlier, negative experiences in East Africa, in early 1997 the government of Rwanda embarked on an ambitious programme for villagisation and resettlement. While the Rwanda authorities present the programme as entirely different from its predecessors, a review of those and of the implementation of villagisation and resettlement in Rwanda shows that this statement cannot hold. Nevertheless, the programme gets considerable support from international agencies. This article investigates how international agencies have accepted and upheld the ‘narrative of difference’ of the Rwandan authorities. It argues that, notwithstanding the claims of the government, lessons from the experiences with villagisation in Mozambique, Ethiopia and Tanzania are relevant for the Rwanda case and should be taken into account.
Relativistic electron heating in laser-produced plasmas
Authors: CAO LIHUA , CHANG TIEQIANG , CHANG WENWEI , YUE ZONGWU
Published: August 2008

Two-dimensional multi-timescale fully electromagnetic relativistic
particle simulation is used to investigate relativistic electron heating in laser-produced
plasmas. When laser pulses with peak intensities 1019 W cm−2 and
different durations (e.g. 118 fs and 442 fs) are incident on overdense plasma slabs with step-like density profiles, the dynamics of plasmas and Fourier frequency spectra from
our particle simulations demonstrate distinctly different properties in hot-electron
temperatures, absorption, relativistic electron heating, and so on. The particular
motions of the critical surfaces are discussed. From the two examples simulated in
this paper, it is concluded that the interactions between plasmas and laser pulses
with the same intensities and different durations are dominated by different mechanisms, which can lead to
dissimilar dynamics of plasmas, relativistic heating, and so on.
Evaluating the efficiency of radiofrequency heating in tokamaks: the impact of orbital
topology and poloidal inhomogeneity
Authors: VAN EESTER DIRK
Published: August 2008

Radiofrequency heating in toroidal geometry is described. Starting from
a general theory, expressions for the dielectric response and the radiofrequency
diffusion operator are obtained. The computationally most efficient simplified
expressions bear a close resemblance to the results of uniform plasma theory, but
differ from them in their interpretation. In cases where the simplified expressions do
not describe the physics faithfully, more general but computationally slower ones
are available. Rigorously accounting for the geometry and the wave field yields
fine structure that is commonly overlooked. Aside from causing the well-known
k∥-upshift or downshift impacting on the Doppler shift, the non-zero poloidal
magnetic field modifies the orbital topology and forces one to account for the poloidal
inhomogeneity of the static magnetic field. The expressions obtained restore
intuition on how an electric field interacts with a charged particle, but, in so doing, cast
doubt on the degree of realism of predictions of simplified models that do not
account for the constructive or destructive interference phenomena introduced by the
orbital topology non-uniformity. The expressions represent a numerical challenge,
but show the necessity for the detailed description: the ‘coarse-graining’
underlying simplified models yields a result that has the right order of magnitude for
interference related to crosstalk between resonances or multiple encounters with
a given resonance, but may be an order of magnitude wrong for predictions on
the combined effect of a poloidal mode spectrum. A Fokker–Planck code BATCH
(Bounce-Averaged Tool for Cyclotron Heating), relying on the expressions obtained,
is presented and some results are discussed.
Nonlinear interaction between a resonance-mode (k∥=0) wave and energetic plasma particles
Authors: SHKLYAR DAVID R.
Published: August 2008

Nonlinear resonant interaction between energetic particles and quasi-electrostatic wave propagating perpendicularly to the ambient magnetic field in a homogeneous plasma is studied in detail, with the main focus on the wave amplification or attenuation caused by resonant interaction. As for k∥ → 0, resonance velocity determined from linear resonance conditions tends to infinity, the interaction under discussion is a completely nonlinear phenomenon. While the wave amplitude may increase or decrease depending on the wave parameters and integral characteristics of the energetic particle distribution function, an essential wave amplification may occur when the wave frequency is close to a multiple of cyclotron harmonic, and when the transversal energy of resonant particles is large enough.
A Malay of Bugis Ancestry: Haji Ibrahim's Strategies of Survival
Authors: van der Putten Jan
Published: August 2008

The descendants of Bugis mercenary forces that liberated Riau from east Sumatran invaders became an integral part of the local Malay community by the mid-nineteenth century. At that time Raja Ali Haji and Haji Ibrahim, two Malay authors of Bugis descent, wrote various tracts to legitimise their presence in Riau and to facilitate Bugis integration into the Malay community, but may have led to continuing divisions along ethnic lines in later years.
Contesting Straits-Malayness: The Fact of Borneo
Authors: Collins James T.
Published: August 2008

Through a discussion of language use in Kalimantan Barat (Western Borneo) a better understanding of cultural and sociolinguistic phenomena that are relevant to any discussion of Malay identity can be achieved. In this complex setting, the colonial nomenclature of Malay and Dayak, though widely adopted by the people of Kalimantan, does not adequately represent the intricacy and the fluidity of social relationships and identities. Colonial knowledge matches neither the results of linguistic research nor what the Malays and Dayaks know about themselves, their languages and their identities.
Strengthening the Local in National Reform: A Cultural Approach to Political Change
Authors: Morrell Elizabeth
Published: August 2008

New Indonesian decentralisation policies have generated strong localisation movements which recall regional history. During the Soeharto years history was invoked as part of an homogenising nationalism. With recent changes in the city of Makassar that process is being reversed to strengthen local participation in redefined national structures.
Invasion, and short- and long-term survival of Babesia divergens (Phylum Apicomplexa) cultures in non-bovine sera and erythrocytes
Authors: ZINTL A. , WESTBROOK C. , MULCAHY G. , SKERRETT H. E. , GRAY J. S.
Published: August 2008

In order to explore the feasibility of producing a Babesia divergens live vaccine free of bovine material contaminants the parasite's ability to grow in human, sheep and horse erythrocytes and serum and serum-free medium was investigated. B. divergens was successfully maintained in bovine erythrocytes overlaid with serum-free HL-1 medium. Supplementation of the culture medium with bovine or sheep serum improved parasite growth (monitored by measuring parasitaemia and uptake of tritiated hypoxanthine) whereas horse and human sera reduced parasite growth. As assessed by Giemsa's stained and FITC-labelled blood smears, the parasite invaded all erythrocyte types. Polyparasitism was less common in sheep and horse erythrocytes than in bovine and human erythrocytes. Accole stages were observed in bovine, human and sheep but not in horse erythrocytes. Proliferation following invasion was higher in human but lower in horse and sheep erythrocytes compared with bovine erythrocytes. Long-term cultures of B. divergens reached similar peak parasitaemias in human, sheep and bovine erythrocytes. Attempts to establish long-term cultures in horse erythrocytes failed. These results suggest that B. divergens is not host specific at the level of host cell attachment and invasion. Instead, parasite survival appears to be decided once the organism has gained access into the cell.
The relationships between endotoxins, nitric oxide and inflammatory cytokines in blood and intestinal tissues in experimental Trypanosoma brucei brucei infections
Authors: NYAKUNDI J. N. , CRAWLEY B. , PENTREATH V. W.
Published: August 2008

Increased levels of circulating endotoxins are a feature of both human and experimental African trypanosomiasis. Studies with rats and mice have shown that these may originate from intestinal damage with altered permeability of the gut epithelium. Endotoxins are potent immunomodulatory substances which can initiate the production of a range of cytokines and mediators from different cell types. In rats infected with T.b. brucei we have examined possible associations of the endotoxin increases with increases in levels of TNF-α, IL-1β, IL-6, IFN-γ and nitric oxide (NO). Significant increases in each substance occurred at days 21 and 33 post-infection (p.i.). The increases in cytokines were highly correlated with the endotoxin levels (e.g. at day 21 p.i. the correlation–regression values were as follows: TNF-α, r = 0·9, P<0·01; IL-1β, r = 0·83, P<0·01; IL-6, r = 0·9, P<0·01; IFN-γ,

r = 0·7, P<0·01). There were also strong correlations between the

increased levels of several individual cytokines. Biopsies of chopped sections of small intestine tissues of rats showed a parallel production of cytokines, again with significant correlations with the circulating endotoxins. The production of NO and cytokines by the intestine may be associated with the increased transepithelial permeability which occurs during the infection.
The relationships between intestinal damage and circulating endotoxins in experimental Trypanosoma brucei brucei infections
Authors: NYAKUNDI J. N. , CRAWLEY B. , SMITH R. A. , PENTREATH V. W.
Published: August 2008

The involvement of intestinal damage in experimental African trypanosomiasis was investigated in rats infected with Trypanosoma brucei brucei by measuring the urinary excretion of the previously administered non-metabolizable sugar probes, D-mannitol and lactulose, and the flux of FITC-dextran across isolated, everted gut segments. There was increased urinary recovery and flux of the sugar probes across the intestine which were significant (P<0·05) and maximum at day 21 of the infection, but subsequently reduced, in the terminal stages of infection (day 33 p.i.). In the case of the everted sac studies the reductions were to less than 25% control values (P<0·001). Levels of circulating endotoxin were increased approximately 3-fold at day 21 p.i., 4-fold at day 33 p.i., compared to controls. At day 21 there was a significant correlation (r = 0·63, P<0·01) between the log endotoxin levels and the increased sugar excretion expressed as the lactulose/mannitol ratios. Histological studies showed damage to the villi, wall thinning and marked cellular infiltrations, which were very prominent in the proximal jejunum and duodenum. These results demonstrate that during trypanosome infections in rats, increased intestinal leakage and increased circulating endotoxins are significant pathological features.
A phylogenetic hypothesis for the distribution of two genotypes of the pig tapeworm Taenia solium worldwide
Authors: NAKAO M. , OKAMOTO M. , SAKO Y. , YAMASAKI H. , NAKAYA K. , ITO A.
Published: August 2008

Genetic polymorphism was determined among 13 isolates of Taenia solium from various regions using PCR-amplified sequences of 2 mitochondrial genes: cytochrome c oxidase subunit 1 and cytochrome b. The 2 phylogenies obtained were similar to each other regardless of the genes examined. The isolates from Asia (China, Thailand, Irian Jaya and India) formed a single cluster, whereas the isolates from Latin America (Mexico, Peru, Ecuador, Bolivia and Brazil) combined with those from Africa (Tanzania, Mozambique and Cameroon) to form an additional cluster. These results and historical data of swine domestication, distribution of pigs and colonization suggest that T. solium was introduced recently into Latin America and Africa from different regions of Europe during the colonial age, which started 500 years ago, and that the tapeworm of another origin independently spread in Asian countries.
Costs of resistance in insect-parasite and insect-parasitoid interactions
Authors: KRAAIJEVELD A. R. , FERRARI J. , GODFRAY H. C. J.
Published: August 2008

Most, if not all, organisms face attack by natural enemies and will be selected to evolve some form of defence. Resistance may have costs as well as its obvious benefits. These costs may be associated with actual defence or with the maintenance of the defensive machinery irrespective of whether a challenge occurs. In this paper, the evidence for costs of resistance in insect-parasite and insect-parasitoid systems is reviewed, with emphasis on two host-parasitoid systems, based onDrosophila melanogasterand pea aphids as hosts. Data from true insect-parasite systems mainly concern the costs of actual defence; evidence for the costs of standing defences is mostly circumstantial. In pea aphids, the costs of standing defences have so far proved elusive. Resistance amongst clones is not correlated with life-time fecundity, whether measured on good or poor quality plants. Successful defence by aD. melanogasterlarva results in a reduction in adult size and fecundity and an increased susceptibility to pupal parasitoids. Costs of standing defences are a reduction in larval competitive ability though these costs only become important when food is limited. It is concluded that costs of resistance can play a pivotal role in the evolutionary and population dynamic interactions between hosts and their parasites.
Variation and polymorphism in helminth parasites
Authors: MAIZELS R. M. , KURNIAWAN-ATMADJA A.
Published: August 2008

There are strong biological, evolutionary and immunological arguments for predicting extensive polymorphism among helminth parasites, but relatively little data and few instances from which the selective forces acting on parasite diversity can be discerned. The paucity of information on intraspecific variation stands in contrast to the fine detail with which helminth species have been delineated by morphological techniques, accentuating a trend towards considering laboratory strains as representative of a relatively invariant organism. However, in the fast-moving evolutionary race between host and parasite one would predict a monomorphic species would be driven to extinction. We review the arena of intraspecific variation for the major helminth parasites, ranging from biological properties such as host or vector preference, to biochemical and immunological characteristics, as well as molecular markers such as DNA sequence variants. These data are summarized, before focusing in more detail on polymorphisms within protein-coding genes of potential relevance to the host-parasite relationship, such as vaccine candidates. In particular, we discuss the available data on a number of major antigens from the filarial nematodeBrugia malayi. Information is currently too sparse to answer the question of whether there is antigenic variation in filariasis, but the indications are that proteins from the blood-borne microfilarial stage show significant intraspecific variability. Future work will define whether polymorphisms in these antigens may be driven by exposure to the host immune response or reflect some other facet of parasite biology.