bluuebunny/crossref_metadata_2025_split huggingface dataset:
Method of reduction of dimensionality in contact and friction mechanics: A linkage between micro and macro scales
Authors: Popov Valentin L. 
Published: March 2013

Abstract
Computer simulations have been an integral part of the technical development process for a long time now. Industrial tribology is one of the last fields in which computer simulations have, until now, played no significant role. This is primarily due to the fact that investigating tribological phenomena requires considering all spatial scales from the macroscopic shape of the contact system down to the micro-scales. In the present paper, we give an overview of the previous work on the so-called method of reduction of dimensionality (MRD), which in our opinion, gives a key for the linking of the micro- and macro-scales in tribological simulations.
MRD in contact mechanics is based on the mapping of some classes of three-dimensional contact problems onto one-dimensional contacts with elastic foundations. The equivalence of three-dimensional systems to those of one-dimension is valid for relations of the indentation depth and the contact force and in some cases for the contact area. For arbitrary bodies of revolution, MRD is exact and provides a sort of “pocket edition” of contact mechanics, giving the possibility of deriving any result of classical contact mechanics with or without adhesion in a very simple way.
A tangential contact problem with and without creep can also be mapped exactly to a one-dimensional system. It can be shown that the reduction method is applicable to contacts of linear visco-elastic bodies as well as to thermal effects in contacts. The method was further validated for randomly rough self-affine surfaces through comparison with direct 3D simulations.
MRD means a huge reduction of computational time for the simulation of contact and friction between rough surfaces accounting for complicated rheology and adhesion. In MRD, not only is the dimension of the space reduced from three to one, but the resulting degrees of freedom are independent (like normal modes in the theory of oscillations). Because of this independence, the method is predestinated for parallel calculation on graphic cards, which brings further acceleration. The method opens completely new possibilities in combining microscopic contact mechanics with the simulation of macroscopic system dynamics without determining the “law of friction” as an intermediate step.
Adhesive and corrosive wear at microscales in different vapor environments
Authors: Shen Sihan , Meng Yonggang 
Published: March 2013

Abstract
Adhesive and corrosive wear at microscales are quantitatively distinguished in lifetime tests of resonant bulk-fabricated silicon microelectromechanical systems (MEMS). By analyzing the oscillation decay characteristics in different vapor environments, we find that wear is dominated by asperity adhesion during the initial stages of rubbing in dry N2 or O2/N2 mixtures; in these situations the transient wear rate is inversely proportional to the wear depth. But in water or ethanol vapors, chemical reactions between the corrosive adsorbed layer and the silicon substrate limit the wear rate to a constant. These observations are consistent with atomic explanations. The differences between adhesive and corrosive wear explain the advantages offered by lubricating with alcohol vapors rather than using dry environments for tribo-MEMS devices. Compared to ethanol, the relatively poor anti-wear effect of water vapor is explained by aggressive and rapid tribo-reactions.
Spatial evolution of friction of a textured wafer surface
Authors: Xiao Huaping , Wang Ke , Fox Grant , Belin Michel , Fontaine Julien , Liang Hong 
Published: March 2013

Abstract
Mechanical failure of integrated circuits and micro-electro-mechanical systems (MEMS) demands new understanding of friction in small devices. In present research, we demonstrated an in situ approach to measure sliding friction of a patterned surface composing multi-materials and structures. The effects of materials and surface morphology on friction and electrical contact resistance were investigated. The material transfer at the interface of dissimilar materials was found to play dominating roles in friction. The current work provides important insights from the fundamentals of friction that benefit the design of new micro-devices.
Genome‐wide association study of the rate of cognitive decline in Alzheimer's disease
Authors: Sherva Richard , Tripodis Yorghos , Bennett David A. , Chibnik Lori B. , Crane Paul K. , de Jager Philip L. , Farrer Lindsay A. , Saykin Andrew J. , Shulman Joshua M. , Naj Adam , Green Robert C. ,   The GENAROAD Consortium, The Alzheimer's Disease Neuroimaging Initiative, and The Alzheimer's Disease Genetics Consortium
Published: March 2013

AbstractBackgroundSubstantial interindividual variability exists in the disease trajectories of Alzheimer's disease (AD) patients. Some decline rapidly whereas others decline slowly, and there are no known explanations for this variability. We describe the first genome‐wide association study to examine rate of cognitive decline in a sample of AD patients with longitudinal measures of cognition.MethodsThe discovery sample was 303 AD cases recruited in the Alzheimer's Disease Neuroimaging Initiative and the replication sample was 323 AD cases from the Religious Orders Study and Rush Memory and Aging Project. In the discovery sample, Alzheimer's Disease Assessment Scale–cognitive subscale responses were tested for association with genome‐wide single‐nucleotide polymorphism (SNP) data using linear regression. We tested the 65 most significant SNPs from the discovery sample for association in the replication sample.ResultsWe identified SNPs in the spondin 1 gene (SPON1), the minor alleles of which were significantly associated with a slower rate of decline (rs11023139, P = 7.0 × 10−11) in the discovery sample. A SPON1 SNP 5.5 kb upstream was associated with decline in the replication sample (rs11606345, P = .002).ConclusionSPON1 has not been previously associated with AD risk, but is plausibly related because the gene product binds to the amyloid precursor protein and inhibits its cleavage by β‐secretase. These data suggest that SPON1 may be associated with the differential rate of cognitive decline in AD.
Formation of epigenetic graphite inclusions in diamond crystals: experimental data
Authors: Nechaev D.V. , Khokhryakov A.F. 
Published: March 2013

Abstract
To elucidate the conditions of formation of epigenetic graphite inclusions in natural diamond, we carried out experiments on high-temperature treatment of natural and synthetic diamond crystals containing microinclusions. The crystal annealing was performed in the CO–CO2 atmosphere at 700–1100 °C and ambient pressure for 15 min to 4 h. The starting and annealed diamond crystals were examined by optical microscopy and Raman spectroscopy. It has been established that the microinclusions begin to change at 900 °C. A temperature increase to 1000 °C induces microcracks around the microinclusions and strong stress in the diamond matrix. The microinclusions turn black and opaque as a result of the formation of amorphous carbon at the diamond–inclusion interface. At 1100 °C, ordered graphite in the form of hexagonal and rounded plates is produced in the microcracks. A hypothesis is put forward that graphitization in natural diamond proceeds by the catalytic mechanism, whereas in synthetic diamond it is the result of pyrolysis of microinclusion hydrocarbons. The obtained data on the genesis of graphite microinclusions in diamond are used to evaluate the temperature of kimberlitic melt at the final stage of formation of diamond deposits.
Petrology and composition of rare-metal alkaline rocks in the South Gobi Desert, Mongolia
Authors: Vladykin N.V. 
Published: March 2013

Abstract
Earlier, a belt of alkali-granite plutons and a carbonatite province were discovered in the South Gobi Desert, Mongolia. The Lugingol pluton of pseudoleucitic syenites with carbonatites was assigned to the alkali-granite belt. However, new dating showed that it is 40 Myr younger than the Khan-Bogdo pluton and a large fault separates it from the alkali-granite belt. In the same part of the South Gobi Desert, a dike series of alkaline K-shonkinites with a rare-metal carbonatite vein was found by V.I. Kovalenko west of the Lugingol pluton, near Mt. Baruun Hasar Uula, and a dike series of alkali and nepheline syenites was found by us northeast of the Lugingol pluton. These data give grounds to distinguish an intrusive complex of K-alkaline shonkinites and leucitic syenites with Late Paleozoic REE-bearing carbonatites. Thus, three alkaline-rock complexes of different ages are distinguished in the South Gobi Desert. We present refined geological maps of these complexes. The plutons of all three complexes are deposits of trace elements (REE, Nb, Zr, Y, P). The chemical composition of the silicate rocks of the complex, rare-metal agpaitic pegmatites, and carbonatite and apatite rare-metal ores was considered in detail. Shonkinites from Mt. Baruun Hasar Uula and the Mountain Pass mine (United States) and their carbonatites, along with the Lugingol carbonatites, belong to a single association of K-alkaline rocks and carbonatites, as evidenced by their identical chemical, mineral, and geochemical rare-metal compositions. Rare-earth element patterns and spidergrams show similarities and differences between the rare-metal rocks of three complexes as well as paragenetic differences between their rare-metal minerals. A rare process is described—the amorphization of rare-metal minerals, related to their high-temperature crystallization in a medium with abnormal silica contents of the Khan-Bogdo pegmatites. The parental magmas of the alkali-carbonatite complexes were generated from the EM-2 contaminated mantle that had undergone recycling, whereas the parental magmas of the Khan-Bogdo agpaitic alkali granites were produced from depleted mantle.
Crystallization of loparite in alkaline fluid-magmatic systems (from experimental and mineralogical data)
Authors: Suk N.I. , Kotel’nikov A.R. , Viryus A.A. 
Published: March 2013

Abstract
We studied loparite-containing rocks (lujaurites, juvites, foyaite-juvites, etc.) sampled from a complex of differentiated rocks and, partly, from a complex of eudialytic lujaurites of the Lovozero alkaline massif. Zoned crystals of loparite (the zoning is due to variations in Ti, Nb, REE, Sr, and Th contents) were examined by microprobing. We also carried out experimental studies of loparite formation in complex silicate–salt systems including sodium carbonate, chloride, fluoride, or sulfate at 400–1200 °C and 1–2 kbar. They show that the composition of loparites depends on the physicochemical conditions of their formation (fluid composition) and that natural loparite can crystallize in a wide range of temperatures. The produced loparite crystals are zoned as a result of variations in Ti, Nb, La, Ce, Y, Ca, and Sr contents, which is probably related to the kinetic specifics of crystallization. Their zoning is similar to that of loparites of the Lovozero massif.
A physicochemical model for the formation of gas hydrates of different structural types in K-2 mud volcano (Kukui Canyon, Lake Baikal)
Authors: Manakov A.Yu. , Khlystov O.M. , Hachikubo A. , Ogienko A.G. 
Published: March 2013

Abstract
Earlier, the coexistence of spatially separated layers of gas hydrates of cubic structures I and II (CS-I, CS-II) in the bottom sediment cores from K-2 mud volcano (Kukui Canyon, Lake Baikal) was described. The layers of gas hydrates of different structural types were situated at different depths and overlain by the lacustrine sediments. Hydrate of CS-II contained 13–15 mol.% ethane, whereas CS-I hydrate contained only 3–4 mol.% ethane. We present a physicochemical model explaining the formation of such an unusual natural object. The model suggests that only CS-I hydrate was originally present at the sampling site. Some geologic event (tectonic shifts, landslide, etc.) stopped natural-gas emanation from the mud volcano or increased the heat flow in the hydrate pool. As a result, CS-I hydrate began to dissolve in interstitial water. We assume that the ethane-enriched CS-II hydrate is an intermediate product of the dissociation (dissolution) of CS-I hydrate.
UNDERSTANDING, GRASPING AND LUCK
Authors: Khalifa Kareem 
Published: March 2013

AbstractRecently, it has been debated as to whether understanding is a species of explanatory knowledge. Those who deny this claim frequently argue that understanding, unlike knowledge, can be lucky. In this paper I argue that current arguments do not support this alleged compatibility between understanding and epistemic luck. First, I argue that understanding requires reliable explanatory evaluation, yet the putative examples of lucky understanding underspecify the extent to which subjects possess this ability. In the course of defending this claim, I also provide a new account of the kind of ‘grasping’ taken to be central to understanding. Second, I show that putative examples of lucky understanding unwittingly deploy a kind of luck that is compatible with knowledge. Finally, appealing to a number of works on explanation and its attendant epistemology, I argue that alleged instances of lucky understanding that overcome these two obstacles will invariably violate certain norms of explanatory inquiry – our paradigmatic understanding-oriented practice. By contrast, knowledge of the same information is immune to these criticisms. Consequently, if understanding is environmentally lucky, it is always inferior to the understanding that a corresponding case of knowledge would provide.
Socio-demographic Profile of Older Adults with HIV/AIDS: Gender and Sexual Orientation Differences
Authors: Brennan David J. , Emlet Charles A. , Brennenstuhl Sarah , Rueda Sergio ,   OHTN Cohort Study Research Team and Staff
Published: March 2013

RÉSUMÉUtilisant des données recueillies par Ontario HIV Treatment Network Cohort Study (OCS), l’objectif principal de cette étude était de décrire les caractéristiques socio-demographiques d’un échantillon de personnes âgées (50 ans et plus) de l’Ontario (n = 1 129) vivant avec le VIH /SIDA. L’objectif secondaire était de comparer quatre sous-echantillons de PVVIH : les femmes (10,6%), les hommes heterosexuels (16,7%), les hommes homosexuels (65,8%), et les hommes bisexuels (6,9%). Ces groupes diffèrent d’une manière significative dans l’âge, l’éducation, le revenu, la nationalité, la race, et le temps passé atteints du VIH. En comparaison à d’autres groupes, les hommes gais et bisexuels (HGB) ont déclaré une stigmatisation plus baisse associée au VIH, et aussi à la stigmatisation sur la divulgation, à la stigmatisation associée à l’image negative de soi, et la stigmatisation associée aux attitudes publiques. HGB ont également signalé une meilleure qualité de vie en ce qui concerne la santé mentale, les scores plus baisses pour la dépression et des scores plus faibles pour l’ inadaptation face à la vie. Ces résultats suggèrent que les services pour les PVVIH plus âgées, y compris la formation sur le VIH pour les prestataires des services pour VIH et les gérontologues, peuvent avoir besoin de répondre aux besoins spécifiques de ces sous-populations.
Genetic characterization of sunflower breeding resources from Argentina: assessing diversity in key open-pollinated and composite populations
Authors: Moreno M. V. , Nishinakamasu V. , Loray M. A. , Alvarez D. , Gieco J. , Vicario A. , Hopp H. E. , Heinz R. A. , Paniego N. , Lia V. V. 
Published: March 2013

Open-pollinated (OPs) and composite populations (CPs) represent a valuable resource for sunflower breeding programmes. However, little is known about the levels and distribution of genetic variation within each of these populations. In this study, quantitative and qualitative traits along with molecular markers were used to evaluate 14 populations from the Instituto Nacional de Tecnología Agropecuaria (INTA) sunflower germplasm collection. These populations were chosen to represent historically important accessions that still play a central role within the INTA sunflower breeding programme due to their extensive variation in diverse agronomically important traits. Nine quantitative and eight qualitative agro-morphological descriptors were recorded and compared with those of a larger set of accessions representative of the phenotypic diversity of the sunflower collection. Molecular characterization was conducted on a total of 311 individuals using 16 microsatellite markers. Overall, the average gene diversity was 0.56 and the average number of alleles per locus was 6.25. No statistically significant differences in genetic diversity were detected between the OPs and CPs. Global estimates ofFSTrevealed very high levels of differentiation among accessions (FST= 0.413,P< 0.05). Population structure analyses were consistent with the observed levels of differentiation and identified two major groups. The results of this work show that high global diversity is preserved within the accessions analysed here. Additionally, this study provides a set of reliable and discriminant markers for the cost-effective molecular characterization of sunflower accessions, along with the guidelines for the delineation of sampling strategies for OPs and CPs, thus aiding the efficient management and exploitation of sunflower germplasm collections.
Controlling Circadian Rhythms by Dark-Pulse Perturbations in Arabidopsis thaliana
Authors: Fukuda Hirokazu , Murase Haruhiko , Tokuda Isao T. 
Published: March 2013

AbstractPlant circadian systems are composed of a large number of self-sustained cellular circadian oscillators. Although the light-dark signal in the natural environment is known to be the most powerful Zeitgeber for the entrainment of cellular oscillators, its effect is too strong to control the plant rhythm into various forms of synchrony. Here, we show that the application of pulse perturbations, i.e., short-term injections of darkness under constant light, provides a novel technique for controlling the synchronized behavior of plant rhythm in Arabidopsis thaliana. By destroying the synchronized cellular activities, circadian singularity was experimentally induced. The present technique is based upon the theory of phase oscillators, which does not require prior knowledge of the detailed dynamics of the plant system but only knowledge of its phase and amplitude responses to the pulse perturbation. Our approach can be applied to diverse problems of controlling biological rhythms in living systems.
Potential for genetic improvement of silkworm through molecular and transgenic approaches.
Authors: Zhao AiChun Zhao AiChun , Zhang Yang Zhang Yang , Long DingPei Long DingPei 
Published: March 2013

Abstract

The silkworm (
Bombyx mori
) makes a great contribution to agricultural development, but traditional breeding is constrained by limited natural genetic resources. Transgenic technologies bring a new opportunity for the genetic improvement of silkworm. This review focuses on the improvement of genetically modified silk, the production of recombinant proteins and resistance breeding by transgenic silkworms and new molecular approaches. The potential of using transgenic silkworm as a tool for producing biomaterials and as a bioreactor for producing recombinant proteins is also discussed.
Two structural components in CNGA3 support regulation of cone CNG channels by phosphoinositides
Authors: Dai Gucan , Peng Changhong , Liu Chunming , Varnum Michael D. 
Published: March 2013

Cyclic nucleotide-gated (CNG) channels in retinal photoreceptors play a crucial role in vertebrate phototransduction. The ligand sensitivity of photoreceptor CNG channels is adjusted during adaptation and in response to paracrine signals, but the mechanisms involved in channel regulation are only partly understood. Heteromeric cone CNGA3 (A3) + CNGB3 (B3) channels are inhibited by membrane phosphoinositides (PIPn), including phosphatidylinositol 3,4,5-triphosphate (PIP3) and phosphatidylinositol 4,5-bisphosphate (PIP2), demonstrating a decrease in apparent affinity for cyclic guanosine monophosphate (cGMP).
Unlike homomeric A1 or A2 channels, A3-only channels paradoxically did not show a decrease in apparent affinity for cGMP after PIPn application. However, PIPn induced an ∼2.5-fold increase in cAMP efficacy for A3 channels. The PIPn-dependent change in cAMP efficacy was abolished by mutations in the C-terminal region (R643Q/R646Q) or by truncation distal to the cyclic nucleotide-binding domain (613X). In addition, A3-613X unmasked a threefold decrease in apparent cGMP affinity with PIPn application to homomeric channels, and this effect was dependent on conserved arginines within the N-terminal region of A3. Together, these results indicate that regulation of A3 subunits by phosphoinositides exhibits two separable components, which depend on structural elements within the N- and C-terminal regions, respectively. Furthermore, both N and C regulatory modules in A3 supported PIPn regulation of heteromeric A3+B3 channels. B3 subunits were not sufficient to confer PIPn sensitivity to heteromeric channels formed with PIPn-insensitive A subunits. Finally, channels formed by mixtures of PIPn-insensitive A3 subunits, having complementary mutations in N- and/or C-terminal regions, restored PIPn regulation, implying that intersubunit N–C interactions help control the phosphoinositide sensitivity of cone CNG channels.
Older and younger workers: the equalling effects of health
Authors: Beck Vanessa , Quinn Martin 
Published: March 2013

PurposeThe purpose of this paper is to consider the statistical evidence on the effects that ill health has on labour market participation and opportunities for younger and older workers in the East Midlands (UK).Design/methodology/approachA statistical analysis of Labour Force Survey data was undertaken to demonstrate that health issues affect older and younger workers alike. This has an equalling effect on labour market opportunities, which should reduce any potential for intergenerational conflict within the workforce.FindingsAlthough health problems that limit activities and affect the amount and kind of work an individual can undertake increase with age, there are high levels of ill health of these kinds within all age groups, including the youngest workers.Research limitations/implicationsThe regional statistical analysis can only provide indications, and further research is required to differentiate which groups of younger and older workers suffer from which types of illnesses, as this has direct implications for their employment.Practical implicationsA more direct consideration of health in employment, education and training policy is required to enable the development of healthy and long‐term working lives that benefit individuals and the economy.Social implicationsThe consideration of the effects of health issues on the labour market should lead to a reconsideration of the rhetoric, and the reality of intergenerational conflict. There might be less reason for such competition than is generally perceived.Originality/valueThe paper considers intergenerational conflict in a labour market context and suggests that health issues have an equalising effect for the relative positions of older and younger workers.