bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastic-Plastic Finite-Element Analyses of Compression Precracking and Its Influence on Subsequent Fatigue-Crack Growth
Authors: Yamada Y. , Newman J. C. , Newman J. C. 
Published: October 2008

Abstract
Compression precracking has been used in a renewed effort to generate fatigue-crack growth rates in the threshold and near-threshold regimes, as an alternative to the traditional load-reduction procedure. But concerns have been expressed on the influence of tensile residual stresses resulting from compressive yielding at the crack-starter notch. This paper uses elastic-plastic, finite-element analyses to study the influence of the tensile residual stresses induced by compression precracking on simulated crack growth under constant-amplitude loading. High-fidelity finite-element models (60 000 to 160 000 DOF) using two-dimensional plane-stress analyses were used to model plastic yielding during compressive loading and simulated fatigue-crack growth through the tensile residual-stress field. The finite-element code was ZIP2D and the course mesh had an element size of 2 μm. A refined mesh had an element size four times smaller (0.5 μm) than the course mesh. Fatigue-crack growth and crack-closure effects were simulated over a wide range in stress ratios (R=0 to 0.8) and load levels, after compression precracking. The crack-tip-opening displacement (CTOD) concept was used to judge the extent of the influence on the tensile residual stresses and the stabilization of the crack-opening loads. It was found that the tensile residual stress field decayed as the crack grew under cyclic loading. Once the crack had reached one compressive plastic-zone size, the tensile residual-stress field had dissipated. However, the stabilization of the crack-opening loads and merging of the CTOD values with and without compression precracking was found to be about 1.5 to 2 times the compressive plastic-zone size at R=0 loading. The effects dissipated at smaller distances from the notch tip for the higher stress ratios. The present results have validated the crack-extension criterion that had been proposed for use in the compressive precracking threshold test method, beyond which, cracks are growing under constant-amplitude (steady-state) behavior.
Percent Shear Area Determination in Charpy Impact Testing
Authors: Manahan M. P. , McCowan C. N. , Manahan M. P. 
Published: October 2008

Abstract
The Charpy test is used throughout the world in a wide range of industries because of its low cost and the fact that notching and dynamic loading produces a crack tip stress field that is conservative for many applications. As a result of its widespread use, there is a compelling motivation to extract as much data as possible from the Charpy test. In a Charpy impact test, three key measurements are typically made: total absorbed energy, lateral expansion, and percent shear fracture area. At present, the measurements of absorbed energy and lateral expansion are quantitative and well defined, but the methods used by most laboratories in the measurement of percent shear are qualitative at best. This is ironic for a 100–year-old test because, as discussed in this paper, it can be reasonably argued that percent shear is the most fundamental and physically meaningful of the three Charpy parameters for brittle fracture characterization. Digital image analysis for shear fracture area is shown to have low uncertainty and be both repeatable and easy to use on a routine basis. Recommendations for changes to the ASTM E23 standard are provided.
Optimization of the Heat Treatment of a 17-4 PH Stainless Steel by Dilatometric Technique
Authors: Gerosa R. , Rivolta B. , Sala A. 
Published: October 2008

Abstract
The precipitation-hardening steels are generally required when high mechanical performances at high temperatures are requested both statically and dynamically. The requested combination of mechanical strength and toughness is achieved by means of an age-hardening treatment which can be carried out at different temperatures and times. Aging 17-4 PH (precipitation-hardening) in the temperature range of 480–620°C results in a precipitation hardening due to the formation of a submicroscopic, copper-rich phase. In the technical literature, the investigation of the phase transformation and the age-hardening behavior of the steel has been carried out at different stages of aging by different techniques, such as transmission electron microscopy studies and x-ray diffraction of the precipitates together with optical and scanning electron microscope analysis of the microstructure. In this paper an alternative method based on dilatometric experiments is proposed to study the kinetics of the age hardening of the steel. The experiments have been carried out at different temperatures on quenched samples and the transformation of the structure during aging has been continuously followed up to 8 h. For a better investigation of the data obtained from the dilatometric analysis, mechanical tests, notch impact tests, and microstructural analysis have been carried out at different and selected parameters of the aging.
Isolation and Characterization of Pluripotent Human Spermatogonial Stem Cell-Derived Cells
Authors: Kossack Nina , Meneses Juanito , Shefi Shai , Nguyen Ha Nam , Chavez Shawn , Nicholas Cory , Gromoll Joerg , Turek Paul J. , Reijo-Pera Renee A. 
Published: October 2008

Abstract
Several reports have documented the derivation of pluripotent cells (multipotent germline stem cells) from spermatogonial stem cells obtained from the adult mouse testis. These spermatogonia-derived stem cells express embryonic stem cell markers and differentiate to the three primary germ layers, as well as the germline. Data indicate that derivation may involve reprogramming of endogenous spermatogonia in culture. Here, we report the derivation of human multipotent germline stem cells (hMGSCs) from a testis biopsy. The cells express distinct markers of pluripotency, form embryoid bodies that contain derivatives of all three germ layers, maintain a normal XY karyotype, are hypomethylated at the H19 locus, and express high levels of telomerase. Teratoma assays indicate the presence of human cells 8 weeks post-transplantation but limited teratoma formation. Thus, these data suggest the potential to derive pluripotent cells from human testis biopsies but indicate a need for novel strategies to optimize hMGSC culture conditions and reprogramming.
Gli2 Is a Novel Regulator of Sox2 Expression in Telencephalic Neuroepithelial Cells
Authors: Takanaga Hiromi , Tsuchida-Straeten Nobuko , Nishide Kenji , Watanabe Akira , Aburatani Hiroyuki , Kondo Toru 
Published: October 2008

Abstract
Multipotential neural stem cells (NSCs) in the central nervous system (CNS) proliferate indefinitely and give rise to neurons, astrocytes, and oligodendrocytes. As NSCs hold promise for CNS regeneration, it is important to understand how their proliferation and differentiation are controlled. We show here that the expression of sox2 gene, which is essential for the maintenance of NSCs, is regulated by the Gli2 transcription factor, a downstream mediator of sonic hedgehog (Shh) signaling: Gli2 binds to an enhancer that is vital for sox2 expression in telencephalic neuroepithelial (NE) cells, which consist of NSCs and neural precursor cells. Overexpression of a truncated form of Gli2 (Gli2ΔC) or Gli2-specific short hairpin RNA (Gli2 shRNA) in NE cells in vivo and in vitro inhibits cell proliferation and the expression of Sox2 and other NSC markers, including Hes1, Hes5, Notch1, CD133, and Bmi1. It also induces premature neuronal differentiation in the developing NE cells. In addition, we show evidence that Sox2 expression decreases significantly in the developing neuroepithelium of Gli2-deficient mice. Finally, we demonstrate that coexpression of Gli2ΔC and Sox2 can rescue the expression of Hes5 and prevent premature neuronal differentiation in NE cells but cannot rescue its proliferation. Thus these data reveal a novel transcriptional cascade, involving Gli2 → Sox2 → Hes5, which maintains the undifferentiated state of telencephalic NE cells.
Petrologic diversity of Plio-Quaternary post-subduction volcanism in northwestern Mexico: An example from Isla San Esteban, Gulf of California
Authors: Calmus Thierry , Pallares Carlos , Maury René C. , Bellon Hervé , Pérez-Segura Efrén , Aguillón-Robles Alfredo , Carreño Ana-Luisa , Bourgois Jacques , Cotten Joseph , Benoit Mathieu 
Published: October 2008

AbstractDuring the Plio-Quaternary, numerous volcanic centres of contrasted compositions were emplaced in the Baja California Peninsula and adjacent Gulf of California. The 43 km2 Isla San Esteban (28o 42 N and 112o 34’ W), located in the central part of the gulf near the Pliocene extinct spreading centre of Lower Tiburón basin, is mostly made of andesitic, dacitic and rhyolitic subaerial lava flows, domes, and pyroclastic deposits. A new geological sketch map of the island is presented, as well as new K-Ar ages ranging from 4.5 to 2.5 Ma. Isla San Esteban lavas belong to two nearly contemporaneous magmatic series emplaced within an extensional tectonic framework related to the continental breakoff followed by the progressive oceanization along the Gulf of California. The first one is medium-K calc-alkaline, and its magmas evolved from basaltic andesites to rhyolites by fractionation of plagioclase, pyroxenes, titanomagnetite and apatite. The second one includes genuine adakites, and dacites derived from them through separation of plagioclase plus amphibole. We propose that these adakites originated from the partial melting of oceanic crust slivers, incorporated to the subcontinental lithospheric mantle during the Late Miocene opening of a slab window followed by the detachment of the deep part of the Farallon slab. The high thermal flux linked to the opening of the Gulf would have triggered their melting, as well as that of the subduction-modified mantle, which represents the likely source of the associated calc-alkaline lavas.
Treatment of Diabetes in Long-Term Care Facilities: A Primary Care Approach
Authors: Johnson Eric L. , Brosseau James D. , Soule Matt , Kolberg Jon 
Published: October 2008

IN BRIEFThe epidemic of type 2 diabetes now affects 190 million people globally,with numbers continuing to grow. In long-term care facilities, ∼ 25% of residents have diabetes, a great majority with type 2 diabetes. Appropriate guidelines and medication use are examined for members of this population,accounting for their unique needs and comorbidities.
La situation linguistique en Casamance et Guinée-Bissau.
Authors: Kihm Alain 
Published: October 2008

A. Kihm—Linguistic Situation in Casamance and Guine-Bissau.
A sketch of the different social positions of Portuguese Creole in Senegal—where it is not a lingua franca but rather the language of one specifie group—and Guine-Bissau where its situation is far closer to that of 'classical' creoles and pidgins. The second part deals with the theoretical and practical problems encountered in the author's attempt to write a modem linguistic description of Kriyol.
Situations urbaines et pratiques sociales en Afrique.
Authors: Gibbal Jean-Marie , Le Bris Emile , Marie Alain , Osmont Annick , Salem Gérard 
Published: October 2008

J.-M. Gibbal, E. Le Bris, A. Marie, A. Osmont, G. Salkm—Urban Situations and Social Practices in Africa.
Editorial presentation of the second special issue of CEA on African towns (not on 'the African town'). In this issue the methodological accent is put on microanalyses concerned mainly with small social groups and qualitative rather than quantitative descriptions of social practices and processes, resulting into three principal themes: strategies of insertion into the urban milieu;'informal' economie actions; a provisional and partial attempt towards a wider synthesis on social stratification processes.
Change and Consciousness in Urban Africa : African Workers in Transition
Authors: Gutkind Peter C. 
Published: October 2008

P. C. W. Gutkind—Changement et conscientisation en Afrique urbaine : les travailleurs africains en transition.
Pourquoi et comment les travailleurs des villes africaines prennent-ils conscience de leur position de classe ? Le développement d'une classe ouvrière urbaine est lié à des circonstances politiques et économiques spécifiques, coloniales et post-coloniales, concernant la main-d'œuvre, ainsi qu'à l'inégale pénétration du capitalisme. De telles conditions déterminent à la fois la conscience politique de classe et l'action — ou l'inaction — de la classe ouvrière, qui vont du soutien aux relations de clientèle au réformisme ou à la recherche militante de transformations radicales. Celle-ci, notamment, est fonction du niveau d'éducation et des efforts syndicaux autant que d'une réaction à l'exploitation et à la répression. Comment cette prise de conscience politique va-t-elle se développer ? Alors que son évolution vers la radica-lisation, c'est-à-dire la lutte de classe, est lente et ambiguë, les travailleurs urbains et ruraux ont à faire face à ces questions : qui sont les ennemis — et les alliés —- de classe ? Quelles alliances rechercher ? « Que faire ? » Comment réagir à l'exploitation ? La conscience de classe doit rejeter le chauvinisme ethnique (mais non la conscience d'une tradition culturelle) et la concurrence, dans la mesure où cette conscience s'enracine dans le contexte historique du changement des modes de production, de l'appropriation des ressources, et de la solidarité d'un mouvement syndical militant. Le tout relève de la question plus générale de savoir quel genre de système de classes existe déjà en Afrique et dans le reste du tiers monde.
Peste et société urbaine à Dakar : l'épidémie de 1914.
Authors: M'Bokolo Elikia 
Published: October 2008

E. M'Bokolo — The Plague and Urban Society in Dakar: The 1914 Epidemie.
Despite outbreaks occurring in various coastal cities since the turn of the century, the authorities in Dakar were taken by surprise when the plague reached the city in 1914. The epidemie lasted for one year and spread into the hinterland despite the attempts to cordon the urban area as soon as the disease had been identified. The sanitary precautions imposed by the administration were generally opposed by the African population, partly because they ran against the grain of beliefs and customs, partly because they looked (and often actually were) discriminatory. The news of the war in Europe also contributed to this negative attitude which impeded the action of the medical service.
Paludisme et variations climatiques saisonnières en savane soudanienne d'Afrique de l'Ouest.
Authors: Delmont Jean 
Published: October 2008

J. Delmont — Malaria and Seasonal Climate Variations in the Sudanic Savannah of West Africa.
Malarial infection rates in the West African savannah follow the yearly hygrométrie cycle which reaches its peak during the rainy season when conditions for the reproduction of Anophèles mosquitoes are met. The variations are far more important than in forest areas where the hygrométrie index is more or less constant.
L'économie politique du royaume abron du Gyaman
Authors: Terray Emmanuel 
Published: October 2008

E. Terray — Political Economy of the Brong Kingdom of Gyaman.
The Brong State secures its necessary resources in various ways: a relatively light tribute levied on peasant communities to which is added the more substantial return from judicial fines. The bulk of the State income results from the surplus labour (Mehrarbeit) of the king's and chiefs' slaves. State expenditures corne under four main headings: ostentatious spending, religious expenses, military outlay and the tribute paid to the Ashanti. There is no specialized 'financial' service. By abolishing slavery and proscribing fines the colonial administration dealt the death blow to the whole structure.
Formation d'États et formation d'une ethnie : le cas des Anyi-Ndenye
Authors: Perrot Claude-Hélène 
Published: October 2008

C.-H. Perrot — State Formation and Formation of an Ethnie Group: The Case of the Ndenye Anyi.
As far as 1887 today's Ndenye community was populated by a congeries of refugees of Nzema, Denkyera and Akan origin organised into small independent States. Yet from 1896 on Ndenye is considered, both by colonial authorities and by its own people, as a single polity and ethnie group. The ethnie consciousness is expressed in the traditions of origin which present as the kingdom's founder Ano Asema, the Anyi king of Aowin, without taking into account the actual hetero-geneity which obtained formerly. The eventual prominence of the Ndenye Anyi is bound to the accumulation of gold and dependents over two centuries. The political organisation was mainly borrowed from the Akan, but with 'son's stools' created for chiefs' sons (not sister's sons) who became heads of new patrilineage. Hence the diminishing importance of kin relationships (no real clan structure) which are superseded by political bonds on a territorial and residential basis. Group consciousness is expressed through royal rites with the participation of ail lineages without any discrimination based upon the date of their incorporation.
L'histoire et la question de l'État. Une lecture de : Les Anyi-Ndenye et le pouvoir au XVIIIe et XIXe siècles, de Claude-Hélène Perrot
Authors: Vidal Claudine 
Published: October 2008

C. Vidal — History and the Problem of the State.
A theoretical and philosophical reflexion on the nature and essence of the State, based upon a comparison between the Anyi (from materials in C.-H. Perrot D. Lit. thesis) and the Rwanda.
The Political Economy of Climatic Hazards : A Village Perspective on Drought and Peasant Economy in a Semi-Arid Région of West Africa.
Authors: Watts Michael John 
Published: October 2008

M. J. Watts - Économie politique des accidents climatiques: perspective villageoise sur la sécheresse et l'économie paysanne dans une région semi-aride d'Afrique occidentale.
A partir d'une analyse des conséquences sociales de la récente sécheresse en pays hausa, une critique de l'approche purement géographique de l'étude des accidents climatiques et de leurs effets sur les sociétés qui en sont victimes. Même la description en termes d'écologie sociale, d'adaptation collective aux contraintes du milieu physique, doit être replacée dans le contexte plus général du système de reproduction de la société en cause. Dans le cas d'espèce étudié, la vulnérabilité des sociétés paysannes hausa résulte du conflit entre deux modes de production, le passage d'un mode précapitaliste local à un mode capitaliste global. L'accident climatique n'est pas « naturel » : s'il agit comme détonateur d'une crise, celle-ci est, en fait, le résultat d'une incapacité du système socio-économique à répondre aux conditions écologiques.
De l' « indigène » à l' « informel », 1955-1982
Authors: Le Pape Marc 
Published: October 2008

M. Le Pape - From 'Native' to 'Informal', 1955-1982.
Studies of Third World urban economies have progressively evolved toward a bipolar distribution: on the one hand, an attempt to identify everywhere the empirical characteristics of a single generai System, the 'informai sector'; on the other hand, an explicitation of the various shapes of particular Systems. Unlike those authors who insist upon antinomies, we are undertaking the historicisation of'informai' objects and notions.
Conflict, Accommodation, and Transformation : The Effect of Islam on Music of the Vai Secret Societies.
Authors: Monts Lester P. 
Published: October 2008

L. P. Monts — Conflit, accommodation et transformation : effet de l'islam sur la musique des sociétés secrètes vaï.
Les associations 6éli et sàndè étaient au centre de la vie sociale vaï et les changements extrinsèques affectant leur structure ont eu un impact significatif sur la musique accompagnant leurs rites et cérémonies. Au début du prosélytisme manding chez les Vaï, l'islam et les sociétés secrètes coexistaient harmonieusement. Toutefois, l'attitude des musulmans à l'égard du rôle de ces sociétés s'est transformée. En conséquence, le 6éli est quasiment inexistant dans certaines régions, tandis qu'une version musulmane du sàndè, appelée môlï sàndè, a fait son apparition récemment. Les matériaux recueillis indiquent que l'assimilation d'idéologies musulmanes a conduit ces associations à des stratégies d'adaptation dans le domaine de la musique, des danses et des masques — stratégies discutées ici à la lumière de l'évolution des Vaï vers une conversion totale à l'islam.
Génies, ancêtres, voisins. Quelques aspects de la relation à la terre chez les Ciranba (Goin) du Burkina-Faso
Authors: Dacher Michèle 
Published: October 2008

M. Dacher—Genii, Ancestors, Neighbours: Aspects ofthe Relation to Earth among the Cirarjba (Goin) (Burkina-Faso).
The Cirarjba (French: "Goin") of south-west Burkina-Faso, 50 000 strong, are an acephalous group of agriculturalists with a bilineal kinship System. They are organized in autonomous villages with the priest of the agrarian cuit as their highest authority. This priest is defined as a direct agnatic descendent of the first human settler, the one who drew a landright covenant with the first real occupant, that is the local génie. However, the actual institution is fully coincident with the assert-ed principle only insofar as the social equilibrium is maintained. The analysis of a succession crisis sheds light upon the Cirarjba's relation to their land and upon their concept of headmanship as well as upon disturbing factors such as conditions of local group settlement, relationships between said groups, population pressure and soil fertility, and opportunities of new means of subsistence.
Le cercueil dans la valise : l'Afrique et l'avenir des Européens dans les romans de Doris Lessing
Authors: Adams Adrian 
Published: October 2008

A. Adams—A Casket in the Wallet. Africa and the White People's Future in the Novels of Doris Lessing.
First part of a comparative analysis of the theme of race relations, past, present and, even more, future in the works of two renown South African women novelists. For Doris Lessing, the only way out of quiet desperation also leads out of this, our, world, also out of literary realism into a kind of philosophie science-fiction.
Corporatisme et colonialisme : approche du cas mozambicain, 1933-1979. II. Crise et survivance du corporatisme colonial, 1960-1979.
Authors: Cahen Michel 
Published: October 2008

M. Cahen —Corporatism and Colonialism: An Approach of Mocambique's Case, 1933-1979. II. Crisis and Survival of Colonial Corporatism, 1960-1979.
The.first part of this paper (CEA 92) described the birth and difncult development of 'colonial corporatism' from 1933 to i960. The second part analyses the evolution of labour, management and State corporative structures since 1960 and the abolition of the Natives' statute and the Native Labour code in 1961-1962. Questions: did economie changes and political and military necessities resuit into an opening of corporative structures to Africans? into awider social basis for these structures? a transformation of the gremios into classical management unions ? In spite of a real administrative strengthening, ' colonial corporatism' never succeeded to overcome its contradictions: it was never more than a projection of metropolitan laws without any dynamics of its own. Thus it collapsed after independence without being able to afford a transition toward classical forms of trade unions. Thus the notion of 'colonial fascism' must be rejected insofar as the colonial Society, oppressive by itself, did not, in contradistinction to metropolitan capitalism, need to rely on fascist structures.
Autour d'al-Hājj Umar Taal. Guerre sainte et Tijaniyya en Afrique de l'Ouest.
Authors: Schmitz Jean 
Published: October 2008

J. Schmitz — On and about Al-Hajj Umar Taal: Holy War and the Tijaniyya in West Africa.
Modem research on West African Islam has shown the importance of local Arabie scholarship in the genesis of political movements centering on legal or legitimate jihad. A synthetic survey of several recent books on the Tijaniyya brotherhood and its leading family, the Taal, sheds a meaningful light upon the dynamics of the political/scholarly network up to and over the colonial period.