bluuebunny/crossref_metadata_2025 huggingface dataset:
‘COLONIAL’ EXPERTS, LOCAL INTERLOCUTORS, INFORMANTS AND THE MAKING OF AN ARCHIVE ON THE ‘TRANSVAAL NDEBELE’, 1930–1989
Authors: LEKGOATHI SEKIBAKIBA PETER
Published: April 2009

The perspectives of African informants and researchers profoundly shaped the writings of government ethnologist Dr. Nicholas Jacobus van Warmelo who not only collected information from local African informants but also relied on African researchers who wrote manuscripts in the vernacular that would constitute part of his archive. This study explores the process of producing knowledge on the ‘Transvaal Ndebele’, and provides an analysis of Van Warmelo's texts and of his researchers' manuscripts. By looking at the role of local interlocutors, I make a case for African agency in shaping the ‘colonial’ expert's conceptions of Ndebele identity. This article provides an account of the co-production of cultural knowledge. Van Warmelo was employed by the South African Native Affairs Department to identify and fix ‘tribes’, a highly political enterprise, and in the process generated an archive. His work was as much appropriated by the apartheid state for social engineering as by Ndebele interlocutors involved in contemporary struggles over chieftainship.
THE CHANGING POLITICS OF SLAVE HERITAGE IN THE WESTERN CAPE, SOUTH AFRICA
Authors: WORDEN NIGEL
Published: April 2009

Changes that have taken place in the ways in which the slave past has been remembered and commemorated in the Western Cape region of South Africa provide insight into the politics of identity in this locality. During most of the twentieth century, public awareness of slave heritage was well buried, but the ending of apartheid provided a new impetus to acknowledge and memorialize the slave past. This engagement in public history has been a vexed process, reflecting contested concepts of knowledge and the use of heritage as both a resource and a weapon in contemporary South African identity struggles.
THE DEVELOPMENT OF KWAME NKRUMAH'S POLITICAL THOUGHT IN EXILE, 1966–1972
Authors: BINEY AMA
Published: April 2009

The focus of this article is an examination of the evolution of Nkrumah's political thought during the last years of his life. There is a discernible radicalization as Nkrumah's intellectual thought developed between 1966 and 1972. He had clearly abandoned the constitutional path to independence and begun to adopt revolutionary armed struggle as the only solution to Africa's myriad problems of capitalism, neo-colonialism and imperialism. The unfolding social and political struggles in Vietnam and Latin America and the unrest in America's black cities impacted profoundly on his thinking. The coup d'état which deposed Nkrumah on 24 February 1966 forced him into exile in neighbouring Guinea-Conakry. It therefore provides the political background against which Nkrumah's intellectual thinking unfolded.
The fluid trampoline: droplets bouncing on a soap film
Authors: GILET TRISTAN , BUSH JOHN W. M.
Published: April 2009

We present the results of a combined experimental and theoretical investigation of droplets falling onto a horizontal soap film. Both static and vertically vibrated soap films are considered. In the static case, a variety of behaviours were observed, including bouncing, crossing and partial coalescence. A quasi-static description of the soap film shape yields a force–displacement relation that provides excellent agreement with experiment, and allows us to model the film as a nonlinear spring. This approach yields an accurate criterion for the transition between droplet bouncing and crossing. Moreover, it allows us to rationalize the observed constancy of the contact time and scaling for the coefficient of restitution in the bouncing states. On the vibrating film, a variety of bouncing behaviours were observed, including simple and complex periodic states, multi-periodicity and chaos. A simple theoretical model is developed that captures the essential physics of the bouncing process, reproducing all observed bouncing states. The model enables us to rationalize the observed coexistence of multiple periodic bouncing states by considering the dependence of the energy transferred to the droplet on the phase of impact. Quantitative agreement between model and experiment is deduced for simple periodic modes, and qualitative agreement for more complex periodic and chaotic bouncing states. Analytical solutions are deduced in the limit of weak forcing and dissipation, yielding insight into the contact time and periodicity of the bouncing states.
Linear and nonlinear processes in two-dimensional mixing layer dynamics and sound radiation
Authors: CHEUNG LAWRENCE C. , LELE SANJIVA K.
Published: April 2009

In this study, we consider the effects of linear and nonlinear instability waves on the near-field dynamics and aeroacoustics of two-dimensional laminar compressible mixing layers. Through a combination of direct computations, linear and nonlinear stability calculations, we demonstrate the significant role of nonlinear mechanisms in accurately describing the behaviour of instability waves. In turn, these processes have a major impact on sound generation mechanisms such as Mach wave radiation and vortex pairing sound. Our simulations show that the mean flow correction, which is required in order to accurately describe the dynamics of large-scale vortical structures, is intrinsically tied to the nonlinear modal interactions and accurate prediction of saturation amplitudes of instability waves. In addition, nonlinear interactions are largely responsible for the excitation and development of higher harmonics in the flow which contribute to the acoustic radiation. Two flow regimes are considered: In supersonic shear layers, where the far-field sound is determined by the instability wave solution at sufficiently high Mach numbers, it is shown that these nonlinear effects directly impact the Mach wave radiation. In subsonic shear layers, correctly capturing the near-field vortical structures and the interactions of the subharmonic and fundamental modes become critical due to the vortex pairing sound generation process. In this regime, a method is proposed to combine the instability wave solution with the Lilley–Goldstein acoustic analogy in order to predict far-field sound.
Clusters of sedimenting high-Reynolds-number particles
Authors: DANIEL W. BRENT , ECKE ROBERT E. , SUBRAMANIAN G. , KOCH DONALD L.
Published: April 2009

We report experiments wherein groups of particles were allowed to sediment in an otherwise quiescent fluid contained in a large tank. The Reynolds number of the particles, defined as Re = aU/ν, ranged from 93 to 425; here, a is the radius of the spherical particle, U its settling velocity and ν the kinematic viscosity of the fluid. The characteristic size of a cluster, in a plane transverse to gravity, was measured by a ‘cluster variance’(〈r2t〉); the latter is defined as the mean square of the transverse coordinates of all constituent particles, averaged over a series of runs. The cluster variance, when plotted as a function of time, exhibited two regimes. There was a quadratic growth in the variance at short times(〈r2t〉 ∝ t2), while for long times, the cluster variance exhibited a slower sublinear growth with 〈r2t〉 ∝ t0.67. A theory, based on isotropic repulsive hydrodynamic interactions between particles, predicts the cluster variance to grow as t2/3 in the limit of long times. The theoretical framework was originally proposed to describe the long-time self-similar evolution of dilute clusters in the limit Re ≪ 1 Subramanian & Koch (J. Fluid Mech., vol. 603, 2008, p. 63), when the probability of wake-mediated interactions between particles remains asymptotically small; the latter requirement is satisfied for homogeneous spherical clusters larger than a critical radius, and is evidently satisfied for planar clusters oriented transversely to gravity. The isotropy of the interactions therefore stems from the isotropy, at large distances, of the disturbance velocity field produced by a single sedimenting particle outside its wake(which contains the compensating inflow to satisfy mass conservation). Herein, the theory is extended to large Re using an empirical correlation for the drag on a sedimenting particle. This allows one to predict, as a function of Re, the numerical prefactors in the expressions for the cluster variance of both spherical and planar clusters; the predictions for the growth exponent remain unchanged. The agreement between the theoretical and experimental growth exponents supports the hypothesis of a self-similar expansion at long times. The prefactor determined from the experimental observations is found to lie between the theoretical predictions for planar and spherical clusters.
Effects of diode current on high power microwave generation in a vircator
Authors: LIU GUOZHI , HUANG WENHUA , SHAO HAO , QIU SHI , WANG HONGJUN , LIU JINGYUE , WANG FENG , YANG ZHANFENG , QIAO YONGZHI
Published: April 2009

An experiment of a virtual cathode oscillator (vircator) built on the low impedance intense electron beam accelerator Flash II is reported. A novel spectrum diagnosis method—a circulating dispersion line—is proposed. A thin oil layer coated graphite cathode is introduced in the experiment to decrease the delay time of the explosive emission process and obtain a homogeneous electron beam emission for improving the high-power microwave (HPM) generation efficiency. The effect of diode current on HPM generation in the vircator system is discussed. The HPM pulse width has a strong connection with the diode current waveform. For most shots, corresponding to the time that microwave emission starts, there is an inflection point in the diode current pulse. Compared with the case that no microwave is generated, the diode current increases more slowly following the inflection point. HPM generation terminates when the beam current reaches the self-pinching critical current of the diode.
Radial characterization of wave magnetic field components during helicon discharge in a small aspect ratio torus
Authors: PAUL MANASH KUMAR , BORA DHIRAJ
Published: April 2009

Wave magnetic field components are measured across the radius (−10 cm ≤ r ≤ 10 cm) for a low-pressure (0.3 mbar) helicon discharge, in a toroidal vacuum chamber of small aspect ratio. Radial variation of the wave magnetic field components, measured during the helicon mode of the discharge, exhibit strong poloidal asymmetry which contribute significantly to the wave-induced helicity. The rise in the magnitude of the radial electric field with radiofrequency power, observed during discharge mode transition, supports better radial confinement of the plasma during the helicon mode of the discharge. The strong dependence of the plasma current on the helicon mode of the discharge has been observed during the present experimental study.
Food and feeding habits ofCaranx crysosfrom the Gulf of Gabès (Tunisia)
Authors: Sley Ayda , Jarboui Othman , Ghorbel Mohamed , Bouain Abderrahmen
Published: April 2009

The diet of blue runnerCaranx crysos(Carangidae) in the Gulf of Gabès (Tunisia, Mediterranean) is described from analysis of stomach contents (N = 1668 fish). The majority of samples were obtained from commercial purse seine and gill-net catches. The index of vacuity (%VI) was relatively high (58.7%) and differed significantly across months. Blue runner is an opportunistic predator that consumes mostly pelagic organisms, with benthic prey representing only a small proportion of the diet. The diet was quantified using the frequency of occurrence (%F), numerical abundance (%N), weight (%W) and the index of relative importance (IRI and %IRI) for each prey taxa.

The most important prey categories were teleosts (%IRI = 83.4) and crustaceans (%IRI = 16.6), with molluscs only observed occasionally (%IRI < 0.1). Fish were also the dominant food items in both terms of weight (89.60%) and frequency of occurrence (82.44%). In terms of numerical abundance, crustaceans were the most abundant prey (78.07%). Ontogenetic and seasonal differences in the diet were observed, although there was no difference between the diets of males and females.
Fecundity of Nephrops norvegicus from the Irish Sea
Authors: McQuaid N. , Briggs R.P. , Roberts D.
Published: April 2009

Potential fecundity, number of oocytes in the mature ovary, and realized fecundity, number of eggs extruded and attached to the pleopods of female Nephrops, caught at the start of the incubation period were estimated for females from the eastern and western Irish Sea grounds. Potential fecundity was found to differ significantly between eastern and western Irish Sea stocks, while realized fecundity did not differ between areas. Inter-year comparison of realized fecundity, and effective fecundity (the number of mature eggs on the pleopods of females at the end of the incubation period) in the western Irish Sea stocks revealed no significant variation over time. Egg loss during the transition from oocytes in the ovary to mature eggs increased with female size, ranging from 40% at 25 mm carapace length (CL) to 65% at 40 mm CL. No relationship was found between egg diameter or volume and female size.
Summer distribution of fish larvae in northern Aegean Sea
Authors: Tsikliras Athanassios C. , Koutrakis Emmanuil T. , Sylaios Georgios K. , Kallianiotis Argyris A.
Published: April 2009

Larval fish and hydrographic data were collected in Kavala Gulf (northern Aegean Sea) across a fine scale grid of 17 stations in two surveys, carried out in the beginning of July 2002 and 2003. Despite the different taxonomic resolution and excluding the unidentified larvae, 22 taxa were caught in 2002 and 27 in 2003. Seventeen taxa were present in both years' collections. A total of 833 larvae were collected during the two samplings. The adults of several larvae caught, although sometimes at very low concentrations, are species with high commercial value or represent a major proportion of the captured production of the northern Aegean Sea. The larvae of European anchovy (Engraulis encrasicolus) were most abundant in both years followed by the brown comber (Serranus hepatus), the gobies (Gobius sp.) and, only for 2003, round sardinella (Sardinella aurita). Maximum anchovy larval densities reached 4145/10 m2 and 13852/10 m2 in the 2002 and 2003 surveys, respectively. The spatial extent of anchovy larvae was also high as they were collected at 12 stations in 2002 and at 15 in 2003. Besides water circulation, the spatial distribution of fish larvae was largely influenced by temperature, salinity and dissolved oxygen.
Toxocariasis/cysticercosis seroprevalence in a long-term rural settlement, São Paulo, Brazil
Authors: PRESTES-CARNEIRO L. E. , SOUZA D. H. P. , MORENO G. C. , TROIANI C. , SANTARÉM V. , ZAGO S. C. S. , MIGUEL N. A. , FREITAS S. B. Z. , FARIA R. , MARTINI L. , RUBINSKY-ELEFANT G. , IHA A. , VAZ A. J.
Published: April 2009

Seroprevalence ofToxocaraandTaenia soliumand risk factors for infection with these parasites were explored in a long-term rural settlement in São Paulo state, Brazil. An ELISA for the detection of anti-ToxocaraIgG and IgE and anti-T. soliumcysticerci was standardized usingToxocaraexcretory-secretory antigens (TES) obtained from the cultured second-stage larvae ofT. canisand by vesicular fluid antigen fromTaenia crassiceps cysticerci(VF). For cysticercosis, the reactive ELISA samples were assayed by Western blot using 18 kDa and 14 kDa proteins purified from VF. Out of 182 subjects, 25 (13·7%) presented anti-ToxocaraIgG and a positive correlation between total IgE and the reactive index of specific anti-TES IgE (P=0·0265) was found amongst the subjects found seropositive for anti-ToxocaraIgG. In these individuals 38·0% showed ocular manifestations. The frequency of anti-T. soliumcysticerci confirmed by Western blot was 0·6%. Seropositivity forToxocarawas correlated with low educational levels and the owning of dogs. Embryonated eggs ofToxocaraspp. were found in 43·3% of the analysed areas.
Reduction of parasite levels in blood improves pregnancy outcome during experimentalTrypanosoma cruziinfection
Authors: SOLANA M. E. , ALBA SOTO C. D. , FERNÁNDEZ M. C. , PONCINI C. V. , POSTAN M. , GONZÁLEZ CAPPA S. M.
Published: April 2009

Infection with a myotropicTrypanosoma cruziclone induces maternal fertility failure. In the current work, we evaluated whether reduction of maternal parasitaemia before mating has beneficial effects on pregnancy outcome. Female mice were subjected to benznidazole (Bz) treatment after infection. On day 30 of therapy, mating was assessed and pregnancy outcome was determined on day 14 of gestation. Fetal resorptions diminished inT. cruzi-infected Bz-treated mice compared withT. cruzi-infected untreated mice. This was in agreement with the reduction in the blood/solid tissue parasite load and with the percentage of necrotic foci in placental samples fromT. cruzi-infected Bz-treated females. To study eventual changes in the immune homeostasis ofT. cruzi-infected Bz-treated mice, activation of the immune system was evaluated at the end of Bz therapy and before mating. We found specific IgG1reduction resulting in a predominance of specific IgG2a, reduced numbers of CD69+CD4+cells and diminished frequency and numbers of CD44+T cells. Concanavalin A-stimulated splenocytes fromT. cruzi-infected Bz-treated mice produced higher amounts of IFN-γ thanT. cruzi-infected untreated mice. These results indicate that reduction of maternal parasite load improves pregnancy outcome. These findings correlate with a favourable modulation of the immune response.
The evolution of the knowledge of cat and dog coccidia
Authors: DUBEY J. P.
Published: April 2009

Before the discovery ofToxoplasma gondiias a coccidium of the cat in 1970, cat and dog coccidia were classified in the genusIsosporaand considered of little clinical or zoonotic significance. Since 1970, several new (Hammondiasp.,Neosporasp.) and previously described species, includingSarcocystis, Besnoitia, andCryptosporidiumhave been found as coccidians of cats and dogs with clinical and zoonotic significance. In the present paper I review salient features of the evolution of cat and dog coccidia.
Echinococcus,GiardiaandCryptosporidium: observational studies challenging accepted dogma
Authors: THOMPSON R. C. A.
Published: April 2009

The development ofin vitroculture systems that allow the maintenance, and support the development ofEchinococcus,GiardiaandCryptosporidiumin the laboratory have had a significant impact on their biology and taxonomy and the epidemiology of infections they cause. This short retrospective review demonstrates how radical shifts in our understanding have occurred as a result of being able to grow these organisms in culture, and how molecular tools have helped in the interpretation of such research that often reflects the observations of earlier workers.
SERIAL STRUCTURES IN ROBERTO GERHARD'S FIRST AND SECOND SYMPHONIES
Authors: Sproston Darren
Published: April 2009

Roberto Gerhard described the problem of structure in the following manner:

My favourite simile is the experience of flying. Imagine yourself sitting next to the pilot of a glider aircraft. Your first problem is that of getting airborne. So it is, metaphorically speaking, with musical form. Your second problem is to keep airborne, how to take advantage of every condition that may confront you in the air, currents, countercurrents, air pockets and so forth; how to navigate your craft and set a course. Your third problem, when in sight of your destination, is (naturally) how to come down.

Believe me the hazards of the take off and the landing are conspicuous in musical form too. If you have been watching your pilot all the time, you will have realised how his skill, his reflexes, his compass-readings, his judgement of hazards and chance happenings combine instant by instant and result in choice, in doing this rather than that. In short you have been witnessing an activity which consists of a chain of decisions taken in full course of the operation. That, I submit, applies exactly to musical form. A chain of decisions, subserving an overall design and steering a course of action. Naturally they ought to be the right decisions every time, or things may go wrong. If you have to bale out or crash land the thing is not considered to be quite as successful.
The Alberta hip and knee replacement project: A model for health technology assessment based on comparative effectiveness of clinical pathways
Authors: Gooch Katherine L. , Smith Douglas , Wasylak Tracy , Faris Peter D. , Marshall Deborah A. , Khong Hoa , Hibbert Julie E. , Parker Robyn D. , Zernicke Ronald F. , Beaupre Lauren , Pearce Tim , Johnston D. W. C. , Frank Cyril B.
Published: April 2009

Background:The Alberta Hip and Knee Replacement Project developed a new evidence-based clinical pathway (NCP) for total hip (THR) and knee (TKR) replacement. The aim was to facilitate the delivery of services in a timely and cost-effective manner while achieving the highest quality of care for the patient across the full continuum of care from patient referral to an orthopedic surgeon through surgery, recovery, and rehabilitation. The purpose of this article is to provide an overview of the study design, rationale, and execution of this project as a model for health technology assessment based on comparative effectiveness of alternative clinical pathways.

Methods:A pragmatic randomized controlled trial study design was used to evaluate the NCP compared with the standard of care (SOC) for these procedures. The pragmatic study design was selected as a rigorous approach to produce high quality evidence suitable for informing decisions between relevant interventions in real clinical practice. The NCP was evaluated in three of the nine regional health authorities (RHAs) in Alberta with dedicated central intake clinics offering multidisciplinary care teams, constituting 80 percent of THR and TKR surgeries performed annually in Alberta. Patients were identified in the offices of twenty orthopedic surgeons who routinely performed THR or TKR surgeries. Evaluation outcome measures were based on the six dimensions of the Alberta Quality Matrix for Health (AQMH): acceptability, accessibility, appropriateness, effectiveness, efficiency and safety. Data were collected prospectively through patient self-completed questionnaires at baseline and 3 and 12 months after surgery, ambulatory and inpatient chart reviews, and electronic administrative data.

Results:The trial design was successful in establishing similar groups for rigorous evaluation. Of the 4,985 patients invited to participate, 69 percent of patients consented. A total of 3,434 patients were randomized: 1,712 to SOC and 1,722 to the NCP. The baseline characteristics of patients in the two study arms, including demographics, comorbidity as measured by CDS and exposure to pain medications, and health-related quality of life, as measured by Western Ontario and McMaster Universities Osteoarthritis Index and Short Form-36, were similar.

Conclusions:The Alberta Hip and Knee Replacement Project demonstrates the feasibility and advantages of applying a pragmatic randomized controlled trial to ascertain comparative effectiveness. This is a model for health technology assessment that incorporates how clinical pathways can be effectively evaluated.
Health technology assessment: A comprehensive framework for evidence-based recommendations in Ontario
Authors: Johnson Ana P. , Sikich Nancy J. , Evans Gerald , Evans William , Giacomini Mita , Glendining Murray , Krahn Murray , Levin Les , Oh Paul , Perera Charmaine
Published: April 2009

Objectives:This study describes the development of a framework for health technology decisions, for Ontario Health Technology Advisory Committee (OHTAC) in Ontario, Canada.

Methods:OHTAC convened a “Decision Determinants Sub-Committee” in January 2007, which undertook a systematic literature review and conducted key informant interviews to develop an explicit decision-making framework.

Results:The “Decision Determinants Sub-Committee” offered recommendations about decision criteria, and the process by which decisions are made. Decision criteria include (i) overall clinical benefit, (ii) consistency with societal and ethical values, (iii) value for money, and (iv) feasibility of adoption into the health system. The decision process should be transparent and fair and should use a deliberative process in delivering recommendations.

Conclusions:This methodology is currently being pilot tested in a live environment: OHTAC. It will be evaluated and revised according to its feasibility, acceptability, and perceived usefulness.
Cost-effectiveness of human papillomavirus vaccination in Belgium: Do not forget about cervical cancer screening
Authors: Thiry Nancy , De Laet Chris , Hulstaert Frank , Neyt Mattias , Huybrechts Michel , Cleemput Irina
Published: April 2009

Objectives:The cost-effectiveness of adding a human papillomavirus (HPV) vaccination program in 12-year-old females to the recommended cervical cancer screening in Belgium is examined. Moreover, the health and economic consequences of a potential decline in screening uptake after initiation of a HPV vaccination program are investigated.

Methods:A static Markov model is developed to estimate the direct effect of vaccination on precancerous lesions and cervical cancers.

Results:Vaccination is estimated to avoid 20 percent of the cervical cancers occurring in a 12-year-old girls' cohort and to cost €32,665 per quality-adjusted life-year (QALY) gained (95 percent credibility interval [CrI]: €17,447 to €68,078), assuming a booster injection after 10 years, a limited duration of protection and discounting costs and effects at 3 percent and 1.5 percent, respectively. Assuming lifelong protection, HPV vaccination is estimated to cost €14,382 (95 percent CrI: €9,238 to €25,644) per QALY gained, while avoiding 50 percent of the cervical cancer cases. In the base-case, a 10 percent reduction in screening compliance after vaccination obliterates the effect of vaccination on cervical cancer cases avoided, whereas further declines in the level of screening compliance even turned out to be detrimental for the cohort's health, inducing a mean loss in QALYs and life-year gained compared with the situation prevaccination.

Conclusions:An HPV vaccination program should only be considered if the level of screening after vaccination can be maintained.
Hölder-differentiability of Gibbs distribution functions
Authors: KESSEBÖHMER MARC , STRATMANN BERND O.
Published: April 2009

In this paper we give non-trivial applications of the thermodynamic formalism to the theory of distribution functions of Gibbs measures (devil's staircases) supported on limit sets of finitely generated conformal iterated function systems in ℝ. For a large class of these Gibbs states we determine the Hausdorff dimension of the set of points at which the distribution function of these measures is not α-Hölder-differentiable. The obtained results give significant extensions of recent work by Darst, Dekking, Falconer, Li, Morris and Xiao. In particular, our results clearly show that the results of these authors have their natural home within the thermodynamic formalism.
Ethical Rules and Codes of Honor Related to Museum Activities: A Complementary Support to the Private International Law Approach Concerning the Circulation of Cultural Property
Authors: Frigo Manlio
Published: April 2009

The role of ethical rules and codes of conduct in the field of art law and international protection of cultural property, together with the adoption of the relevant international conventions, has constantly increased in the last decades. This article considers the main codes of conduct drafted by international organizations as well as international, national, public, and private institutions, federations, and associations. The focus is on their influence on international trade as instruments of art market regulation. Specific attention is paid to the interaction with the private international law approach and to a survey of both direct and indirect effects of these rules on the international circulation of cultural property.
Hodge cycles on Kuga fiber varieties
Authors: Lee Min Ho
Published: April 2009

We determine the dimension of the space of Hodge cycles for the generic fibers of the Kuga fiber varieties associated to certain quaternion algebras.
On indecomposable decompositions of CS-modules
Authors: Dung Nguyen V.
Published: April 2009

It is shown that, over any ring R, the direct sum M = ⊕i∈IMi of uniform right R-modules Mi with local endomorphism rings is a CS-module if and only if every uniform submodule of M is essential in a direct summand of M and there does not exist an infinite sequence of non-isomorphic monomorphisms , with distinct in ∈ I. As a consequence, any CS-module which is a direct sum of submodules with local endomorphism rings has the exchange property.
Universal and proximately universal limits
Authors: Čerin Zvonko , Sanjurjo Jóse M. R.
Published: April 2009

We present sufficient conditions on an approximate mapping F: X → Y of approximate inverse systems in order that the limit f: X → Y of F is a universal map in the sense of Holsztyński. A similar theorem holds for a more restrictive concept of a proximately universal map introduced recently by the second author. We get as corollaries some sufficient conditions on an approximate inverse system implying that the its limit has the (proximate) fixed point property. In particular, every chainable compact Hausdorif space has the proximate fixed point property.
Hilbert C*-modules and conditional expectations on crossed products
Authors: Khoshkam Mahmood
Published: April 2009

In this paper, we study the structure of certain conditional expectation on crossed product C*-algebra. In particular, we prove that the index of a conditional expectation E: B → A is finite if and only if the index of the induced expectation from B ⋊ G onto A ⋊ G is finite where G is a discrete group acting on B.
Measurable Hilbert sheaves
Authors: Wendt Michael A.
Published: April 2009

We describe measurable Hilbert sheaves as Hilbert space objects in a sheaf category constructed from a measure space. These are quite useful for the interpretation of the direct integral of Hilbert spaces as an indexed functor. We set up a framework to put this and similar constructions of operator theory on an indexed categorical footing.
Exponentially bounded positive-definite functions on a commutative hypergroup
Authors: Bloom Walter R. , Ressel Paul
Published: April 2009

In this paper we make use of semigroup methods on the space of compactly supported measures to obtain a Bochner representation for α-bounded positive-definite functions on a commutative hypergroup.
On the vanishing problem of string classes
Authors: Kuribayashi Katsuhiko
Published: April 2009

The ordinary string class is an obstruction to lift the structure group LSpin(n) of a loop group bundle LQ → LM to the universal central extension of LSpin(n) by the circle. The vanishing problem of the ordinary string class and generalized string classes are considered from the viewpoint of the ring structure of the cohomology H*(M; R).
An extension theorem for integral representations
Authors: Knapp Wolfgang , Schmid Peter
Published: April 2009

By a fundamental theorem of Brauer every irreducible character of a finite groupGcan be written in the field Q(εm) ofmth roots of unity wheremis the exponent ofG. Is it always possible to find a matrix representation over its ring Z[εm] of integers? In the present paper it is shown that this holds true provided it is valid for the quasisimple groups. The reduction to such groups relies on a useful extension theorem for integral representations. Iwasawa theory on class groups of cyclotomic fields gives evidence that the answer is at least affirmative when the exponent is replaced by the order, and provides for a general qualitative result.
Some characterizations of partial exchangeability
Authors: Ivanoff B. G. , Weber N. C.
Published: April 2009

Kallenberg [2] introduced the concept of F-exchangeable sequences of random variables and produced some characterizations of F-exchangeability in terms of stopping times. In this paper ways of extending the concept of F-exchangeability to doubly indexed arrays of random variables are explored and some characterizations obtained for row and column exchangebale arrays, weakly exchangeable arrays and separately exchangeable continuous processes.
Homogeneous solutions of the generalized heat equation
Authors: Kochneff E.
Published: April 2009

We discuss expansions of solutions of the generalized heat equation which have a singularity at zero in terms of two sequences of homogeneous solutions.
Varieties of distributive lattices with unary operations I
Authors: Priestley H. A.
Published: April 2009

A unified study is undertaken of finitely generated varieties HSP () of distributive lattices with unary operations, extending work of Cornish. The generating algebra () is assusmed to be of the form (P; ∧, ∨, 0, 1, {fμ}), where eachfμis an endomorphism or dual endomorphism of (P; ∧, ∨, 0, 1), and the Priestly dual of this lattice is an ordered semigroup N whose elements act by left multiplication to give the maps dual to the operationsfμ. Duality theory is fully developed within this framework, into which fit many varieties arising in algebraic logic. Conditions on N are given for the natural and Priestley dualities for HSP () to be essentially the same, so that,inter alia, coproducts in HSP () are enriched D-coproducts.
Locally finite affine complete varieties
Authors: Kaarli Kalle
Published: April 2009

The main results of the paper are the following: 1. Every locally finite affine complete variety admits a near unanimity term; 2. A locally finite congruence distributive variety is affine complete if and only if all its algebras with no proper subalgebras are affine complete and the variety is generated by one of such algebras. The first of these results sharpens a result of McKenzie asserting that all locally finite affine complete varieties are congruence distributive. The second one generalizes the result by Kaarli and Pixley that characterizes arithmetical affine complete varieties.
Compactness theorems for critical metrics of the Weyl functional on compact Kähler surfaces
Authors: Chang Shun-Cheng
Published: April 2009

In this note, we propose an extension of the compactness property for Kähler-Einstein metrics to critical metrics of Weyl functional on compact Kähler surfaces.
On generalized theta series liftings
Authors: Lee Min Ho
Published: April 2009

We generalize dual reductive pairs by using reductive groups that are not necessarily subgroups of symplectic groups and construct the corresponding theta-series liftings for certain types of automorphic forms. We also discuss connections of such generalized theta-series liftings with families of abelian varieties parametrized by an arithmetic variety.
Certain extensions and factorizations of α-complete homomorphisms in archimedean lattice-ordered groups
Authors: Hager Anthony W. , Kizanis Ann
Published: April 2009

As a consequence of general principles, we add to the array of ‘hulls’ in the category Arch (of archimedean ℓ-groups with ℓ-homomorphisms) and in its non-full subcategory W (whose objects have distinguished weak order unit, whose morphisms preserve the unit). The following discussion refers to either Arch or W. Let α be an infinite cardinal number or ∞, let Homα; denote the class of α-complete homomorphisms, and let R be a full epireflective subcategory with reflections denoted rG: G → rG. Then for each G, there is rαG ∈ Homα (G, R) such that for each ϕ ∈ Homα (G, R), there is unique with . Moreover if every rG is an essential embedding, then, for every α and every G, rαG = rG, and every Homα. If and R consists of all epicomplete objects, then every Homw1. For α = ∞, and for any R, every Hom∞.
Lattice embeddings of abelian prime power groups
Authors: Schmidt Roland
Published: April 2009

We solve the following problem which was posed by Barnes in 1962. For which abelian groups G and H of the same prime power order is it possible to embed the subgroup lattice of G in that of H? It follows from Barnes' results and a theorem of Herrmann and Huhn that if there exists such an embedding and G contains three independent elements of order p2, then G and H are isomorphic. This reduces the problem to the case that G is the direct product of cyclic p-groups only two of which have order larger than p. We determine all groups H for which the desired embedding exists.
Construction of mixed automorphic forms
Authors: Choie Youngju
Published: April 2009

It has been known that mixed automorphic forms arise naturally as holomorphic forms on elliptic varieties and that they include classical automorphic forms as a special case. In this paper, we show how to construct mixed automorphic forms of type (k, l) from elliptic modular forms to give nontrivial examples of mixed automorphic forms.
A new proof of the Macdonald identities for An−1
Authors: Cooper Shaun
Published: April 2009

A new, elementary proof of the Macdonald identities for An−1 using induction on n is given. Specifically, the Macdonald identity for An is deduced by multiplying the Macdonald identity for An−1 and n Jacobi triple product identities together.
The orders of nonsingular derivations
Authors: Shalev Aner
Published: April 2009

Nonsingular derivations of modular Lie algebras which have finite multiplicative order play a role in the coclass theory for pro-pgroups and Lie algebras. We study the orders of nonsingular derivations of finite-dimensional non-nilpotent Lie algebras of characteristicp> 0. The methods are essentially number-theoretic.

1991Mathematics subject classification (Amer. Math. Soc): primary 17B50; secondary 12E20.
Second order Dehn functions and HNN-extensions
Authors: Wang X. , Pride S. J.
Published: April 2009

In previous work [2] calculations of subquadratic second order Dehn functions for various groups were carried out. In this paper we obtain estimates for upper and lower bounds of second order Dehn functions ofHNN-extensions, and use these to exhibit an infinite number of different superquadratic second order Dehn functions. At the end of the paper several open questions concerning second order Dehn functions of groups are discussed.
The depth of centres of maps on dendrites
Authors: Kato Hisao
Published: April 2009

Xiong proved that if f: I → I is any map of the unit interval I, then the depth of the centre of f is at most 2, and Ye proved that for any map f: T → T of a finite tree T, the depth of the centre of f is at most 3. It is natural to ask whether the result can be dendrites. In this note, we show that there is dendrite D such that for any countable ordinal number λ there is a map f: D →D such that the depth of centre of f is λ. As a corollary, we show that for any countable ordinal number λ there is a map (respectively a homeomorphism) f of a 2-dimensional ball B2 (respectively a 3-dimensional ball B3) such that the depth of centre of f is λ.
Oscillations of higher order neutral differential equations
Authors: Yan Jurang
Published: April 2009

Some new oscillation criteria for higher order neutral functional differential equations of the form n is even, are established.
Generalized functions associated with self-adjoint operators
Authors: Shangping Liu
Published: April 2009

In this paper, from several commutative self-adjoint operators on a Hilbert space, we define a class of spaces of fundamental functions and generalized functions, which are characterized completely by selfadjoint operators. Specially, using the common eigenvectors of these self-adjoint operators, we give the general form of expansion in series of generalized functions
Medial idempotent groupoids III
Authors: Cho Jung R. , Dudek Józef
Published: April 2009

As a sequel to the previous two papers of the second author, we investigate the structure of medial idempotent groupoids byPn-sequences. To complete the series of research, this paper has theree purposes. First, we summarize some results in the previous papers so that this paper can cover the materials presented there. Secondly, using earlier results, we prove a few theorems which show the importance of the medial law in controlling the growth ofPn-sequences of groupoids. Finally, we state some problems and conjectures raised during the series of research.
On Rosenbloom's fixed-point theorem and related results
Authors: Fang Mingliang , Yuan Wenjun
Published: April 2009

In this paper, we improve the Rosenbloom's fixed-point theorem and prove a related normality criterion. We also consider the corresponding unicity theorem for transcendental entire functions.
On the convergence of a sequence of completely positive maps to the identity
Authors: Elliott George A.
Published: April 2009

It is shown that a sequence of completely positive linear maps on a W*-algebra that converges pointwise in norm to the identity converges uniformly.
On families of Cauchy transforms and BMOA
Authors: Muhanna Yusuf Abu , Yallaoui El-Bachir
Published: April 2009

In this paper we prove a number of results on Cauchy transforms of generalized type given by Borel measures supported on the class of analytic functions mapping the unit disc into the unit disk. We also give a BMOA characterization using these families.
Rationality of the generalized binomial coefficients for a multiplicity free action
Authors: Benson Chal , Ratcliff Gail
Published: April 2009

LetVbe a finite dimensional Hermitian vector space andKbe a compact Lie subgroup ofU(V) for which th representation ofKonC[V] is multiplicity free. One obtains a canonical basis {pα} for the spaceC[VR]kofK-invariant polynomials on VRand also a basis {q's. The polynomialpα's yields the homogeneous component of highest degree inqα. The coefficient that express theqα's in terms of thepβ's are the generalized binomial coeffficients of Yan. The main result in this paper shows tht these numbers are rational.
Some Properties on Isologism of Groups
Authors: Moghaddam Mohammad Reza R. , Salemkar Ali Reza
Published: April 2009

In this paper a necessary and sufficient condition will be given for groups to be ν-isologic, with respect to a given variety of groups ν. Its is also shown that every ν-isologism family of a group contains a ν-Hopfian group. Finally we show that ifGis in the variety ν, then every ν-covering group ofGis a Hopfian group.
Locally Convex Spaces with Toeplitz Decompositions
Authors: Paúl Pedro J. , Sáez Carmen , Virués Juan M.
Published: April 2009

A Toeplitz decomposition of a locally convez spaceEinto subspaces (Ek) with continuous projections (Pk) is a decomposition of everyx ∈ Easx = ΣkPkxwhere ordinary summability has been replaced by summability with respect to an infinite and row-finite matrix. We extend to the setting of Toeplitz decompositions a number of results about the locally convex structure of a space with a Schauder decomposition. Namely, we give some necessary or sufficient conditions for being reflexive, a Montel space or a Schwartz space. Roughly speaking, each of these locally convex properties is linked to a property of the convergence of the decomposition. We apply these results to study some structural questions in projective tensor products and spaces with Cesàro bases.
On the Connectedness of the Real Part of Moduli Spaces of Vector Bundles on Real Algebraic Surfaces
Authors: Ballico Edoardo
Published: April 2009

Let X be a smooth projective surface with q(X) = 0 defined over R and M(X;r;c1;c2;H) the moduli space of H-stable rank r vector bundles on X with Chern classes c1 and c2. Assume either r = 3 and X(R) connected or r = 3 and X(R) =ø or r=2 and X(R) = ø. We prove that quite often M is connected.
An Lp Version of the Hardy Theorem for Motion Groups
Authors: Eguchi Masaaki , Koizumi Shin , Kimahara Keisaku
Published: April 2009

We describe a generalization of the Hardy theorem on the motion group. We prove that for some weight functions νω growing very rapidly and a measurable function f, the finiteness of the Lp-norm of vf and the Lq-norm of ωf implies f=0 (almost everywhere).
Hyperbolic Groups are Hyperhopfian
Authors: Daverman Robert J.
Published: April 2009

The main result indicates that every finitely generated, residually finite, torsion-free, cohopfian group having on free Abelian subgroup of rank two is hyperhopfian. The argument relies on earlier work and ideas of Hirshon. As a corollary, fundamental groups of all closed hyperbolic manifolds are hyperhopfian.
Multiplicative isogeny estimates
Authors: Masser David
Published: April 2009

The theory of isogeny estimates for Abelian varieties provides ‘additive bounds’ of the form ‘d is at most B’ for the degrees d of certain isogenies. We investigate whether these can be improved to ‘multiplicative bounds’ of the form ‘d divides B’. We find that in general the answer is no (Theorem 1), but that sometimes the answer is yes (Theorem 2). Further we apply the affirmative result to the study of exceptional primes ℒ in connexion with modular Galois representations coming from elliptic curves: we prove that the additive bounds for ℒ of Masser and Wüstholz (1993) can be improved to multiplicative bounds (Theorem 3).
On the absence of cohomological finiteness in wreath products
Authors: Baumslag Gilbert , Bridson Martin R. , Gruenberg Karl W.
Published: April 2009

The wreath product W = A ≀ T, where A ≠ 1, is of type F P2 if and only if T is finite and A is of type F P2.
Products of spherical derivatives and normal functions
Authors: Huaihui Chen , Lappan Peter
Published: April 2009

Chen and Gu [1] have given some results relating to normal families, and, in this paper, we give versions of these results valid for normal functions. In the process, we improve some of our previous results involving products of certain spherical derivatives as they relate to normal functions. Some examples are given to show the sharpness of our results.
On strings of consecutive integers with no large prime factors
Authors: Balog Antal , Wooley Trevor D.
Published: April 2009

We investigate conditions which ensure that systems of binomial polynomials with integer coefficients are simultaneously free of large prime factors. In particular, for each positive number ε, we show that there are infinitely many strings of consecutive integers of size about n, free of prime factors exceeding nε, with the length of the strings tending to infinity with speed log log log log n.
Direct products of automatic semigroups
Authors: Campbell C. M. , Robertson E. F. , Ruškuc N. , Thomas R. M.
Published: April 2009

It is known that the direct product of two automatic groups is automatic. The notion of automaticity bas been extended to semigroups, and this for groups has been generalized to automatic monoids. However, the direct product of two automatic semigroups need not be finitely generated and hence not automatic.

Robertson, Ruškuc and Wiegold have determined necessary and sufficient conditions for the direct product of two finitely generated semigroups to be finitely generated. Building on this, we prove the following. Let S and T be automatic semigroups; if S and T are infinite, then S × T is automatic if and only if S2 = S and T2 = T; if S is finite and T is infinite, then S × T is automatic if and only if S2 = S. As a consequence, we have that, if S and T are automatic semigroups, then S × T is automatic if and only if S × T is finitely generated.
Associativity of the regular semidirect product of existence varieties
Authors: Billhardt Bernd , Szendrei Mária B.
Published: April 2009

The associativity of the regular semidirect product of existence varieties introduced by Jones and Trotter was proved under certain condition by Reilly and Zhang. Here we estabilsh associativity in many new cases. Moreover, we prove that the regular semidirect product is right distributive with respect to the join operation. In particular, both associativity and right distriutivity yiel within the varieties of completely simple semigroups. Analogous results are obtainedj for e-pseudovarieties of finite regular semigroups.