36 resultados para Latex spheres
Resumo:
In this paper we define the structural information content of graphs as their corresponding graph entropy. This definition is based on local vertex functionals obtained by calculating-spheres via the algorithm of Dijkstra. We prove that the graph entropy and, hence, the local vertex functionals can be computed with polynomial time complexity enabling the application of our measure for large graphs. In this paper we present numerical results for the graph entropy of chemical graphs and discuss resulting properties. (C) 2007 Elsevier Ltd. All rights reserved.
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Introduction: The laboratory mouse is a powerful tool in cardiovascular research. In this report, we describe a method for a reproducible mouse myocardial infarction model that would allow subsequent comparative and quantitative studies on molecular and pathophysiological variables. Methods: (A) The distribution of the major coronary arteries including the septal artery in the left ventricle of the C57BL/6J mice (n=20) was mapped by perfusion of latex dye or fluorescent beads through the aorta. (B) The territory of myocardial infarction after the ligation of the most proximal aspect of the left anterior descending (LAD) coronary artery was quantified. (C) The consistency in the histological changes parallel to the infarction at different time points was analyzed. Results: (A) The coronary artery tree of the mouse is different from human and, particularly, in regard to the blood supply of the septum. (B) Contrary to previous belief, the septal coronary artery in the mouse is variable in origin. (C) A constant ligation of the LAD immediately below the left auricular level ensures a statistically significant reproducible infarct size. (D) The ischemic changes can be monitored at a histological level in a way similar to what is described in the human. Conclusion: We illustrate a method for maximal reproducibility of experimental acute myocardial infarction in the mouse model, due to a consistent loss of perfusion in the lower half of the left ventricle. This will allow the study of molecular and physiological variables in a controlled and quantifiable experimental model environment. (C) 2004 Elsevier Inc. All rights reserved.
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Inclusion is increasingly understood as an educational reform that responds to the diversity of all learners, challenging the marginalization, exclusion and underachievement which may result from all forms of ‘difference’. Leadership for inclusion is conceptualized here as driving a constant struggle to create shared meanings of inclusion and to build collaborative practice, an effort that needs to be rooted in critical practice lest it risk replicating existing patterns of disadvantage. In response to calls for further research that challenge how school leaders conceptualize inclusion and for research that investigates how leaders enact their understandings of inclusion, this paper aims to increase our understanding of the extent to which leadership vision can map onto a school’s culture and of the organizational conditions in schools that drive responses to diversity. We investigate the enactment of leadership for inclusion in the troubled context of Northern Ireland by looking at two schools that primarily aim to integrate Catholic and Protestant children but which are also sites for a range of other dimensions of student ‘difference’ to come together. Whilst the two schools express differing visions of the integration of Catholics and Protestants, leadership vision of inclusion is enacted by members of the school community with a consensus around this vision brought about by formal and informal aspects of school culture. Multiple and intersecting spheres of difference stimulate a concerted educational response in both schools but integration remains the primary focus. In this divided society, religious diversity poses a significant challenge to inclusion and further support is required from leaders to enable teachers to break through cultural restraints.
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By investigating the social dynamics of home in one of the enduring communities of Cairo, this paper reveals the way ordinary people construct and consume their private and public domains on a daily basis. It reveals what is central and what is marginal in the cognitive idea of home. This paper adopts an interdisciplinary strategy of investigation, utilizing sociological and anthropological data to read and visit spatial practices in the home. Building on historical as well as contemporary accounts of residents and families, the concept of home is envisioned as a spectrum of social spheres that is liberated from the physical determinants of space, hence revealing a new domain of part-time spaces and dynamic spatiality. The emergent idea of home intertwines work, domesticity, recreation and hospitality in interplay of space-activity-time relationships. Homes of old Cairo have proved to be responsive to continuous change, and have evolved dynamic forms of the temporal settings required for accommodation of emerging home-based professional activities such as hospitality, home-workers, and care-homes.
Resumo:
Particulate colloids often occur together with proteins in sewage-impacted water. Using Bovine Serum Albumin (BSA) as a surrogate for protein in sewage, column experiments investigating the capacity of iron-oxide coated sands to remove latex microspheres from water revealed that microsphere attenuation mechanisms depended on antecedent BSA coverage. Dual pulse experiment (DPE) results suggested that where all BSA was adsorbed, subsequent multiple pore volume microsphere breakthrough curves reflected progressively reduced colloid deposition rates with increasing adsorbed BSA content. Modelling colloid responses suggested adsorption of 1 µg BSA generated the same response as blockage by between 7.1x108 and 2.3x109 deposited microspheres. By contrast, microsphere responses in DPEs where BSA coverage of the deposition sites approached/ reached saturation revealed the coated sand maintained a finite capacity to attenuate microspheres, even when incapable of further BSA adsorption. Subsequent microsphere breakthrough curves demonstrated the matrix’s colloid attenuation capacity progressively increased with continued microsphere deposition. Experimental findings suggested BSA adsorption on the sand surface approaching/ reaching saturation generated attractive deposition sites for colloids, which became progressively more attractive with further colloid deposition (filter ripening). Results demonstrate that adsorption of a single type of protein may either enhance or inhibit colloid mobility in saturated porous media.
Resumo:
We present a mechanism for cooling atoms by a laser beam reflected from a single mirror. The cooling relies on the dipole force and thus in principle applies to arbitrary refractive particles including atoms, molecules, or dielectric spheres. Friction and equilibrium temperatures are derived by an analytic perturbative approach. Finally, semiclassical Monte-Carlo simulations are performed to validate the analytic results.
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Proteins and humic acids are common constituents of waste water. Latex colloids (colloids) acted as surrogates for microorganisms in multiple pulse dynamic column experiments (MPEs) that permitted colloid mobility to be quantified before and after the injection of either BSA (a protein), or Suwannee River humic acid (SRHA).
At low OM coverage colloid breakthrough curves demonstrated both BSA and SRHA reduced colloid deposition rates, but did not affect colloid irreversible deposition mechanisms. By contrast, high levels of SRHA surface coverage not only further reduced the matrix’s ability to attenuate colloids, but also resulted in reversible adsorption of a significant fraction of colloids deposited. Modelling of colloid responses using random sequential adsorption modelling suggested that 1 microgram of SRHA had the same effect as the deposition of 5.90±0.14 x109 colloids; the model suggested that adsorption of the same mass of BSA was equivalent to the deposition of between 7.1x108 and 2.3x109 colloids.
Colloid responses in MPEs where BSA coverage of colloid deposition sites approached saturation demonstrated the sand matrix remained capable of adsorbing colloids. However, in contrast to responses observed in MPEs at low surface coverage, continued colloid injection showed that the sand’s attenuation capacity increased with time, i.e. colloid concentrations declined as more were deposited (filter ripening).
Importance: Study results highlight the contrasting responses that may arise due to the interactions between colloids and OM in porous media. Results not only underscore that colloids can interact differently with various forms of deposited OM, but also that a single type of OM may generate dramatically different responses depending on the degree of surface coverage. The MPE method provides a means of quantifying the influence of OM on microorganism mobility in porous media such as filter beds, which may be used for either drinking water treatment or waste water treatment. In the wider environment study findings have potential to allow more confident predictions of the mobility of sewage derived pathogens discharging to groundwater.
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Localized plasmon resonances of spherical nanovoid arrays strongly enhance solar cell performance by a factor of 3.5 in external quantum efficiency at plasmonic resonances, and a four-fold enhancement in overall power conversion efficiency. Large area substrates of silver nanovoids are electrochemically templated through self-assembled colloidal spheres and organic solar cells fabricated on top. Our design represents a new class of plasmonic photovoltaic enhancement: that of localized plasmon-enhanced absorption within nanovoid structures. Angularly-resolved spectra demonstrate strong localized Mie plasmon modes within the nanovoids. Theoretical modelling shows varied spatial dependence of light intensity within the void region suggesting a first possible route towards Third Generation plasmonic photovoltaics. (C) 2011 Optical Society of America
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Studies on terrorism have traditionally focused on non-state actors who direct violence against liberal states. These studies also tend to focus on political motivations and, therefore, have neglected the economic functions of terrorism. This article challenges the divorce of the political and economic spheres by highlighting how states can use terrorism to realise interconnected political and economic goals. To demonstrate this, we take the case of the paramilitary demobilisation process in Colombia and show how it relates to the US-Colombian free trade agreement. We argue that the demobilisation process fulfils a dual role. First, the process aims to improve the image of the Colombian government required to pass the controversial free trade agreement through US Congress to protect large amounts of US investment in the country. Second, the demobilisation process serves to mask clear continuities in paramilitary terror that serve mutually supportive political and economic functions for US investment in Colombia.
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The relationship between class and intergenerational solidarities in the public and private spheres calls for further conceptual and theoretical development. This article discusses the findings from the first wave of a qualitative longitudinal study entitled Changing Generations, conducted in Ireland in 2011–2012, comprising 100 in-depth interviews with men and women across the age and socioeconomic spectrums. Constructivist grounded theory analysis of the data gives rise to the following postulates: (1) intergenerational solidarity at the family level is strongly contoured by socioeconomic status (SES); (2) intergenerational solidarity evolves as family generations observe each others’ practices and adjust their expectations accordingly; (3) intergenerational solidarity within families is also shaped by the public sphere (the welfare state) that generates varying expectations and levels of solidarity regarding State supports for different age groups, again largely dependent on SES; (4) the liberal welfare state context, especially at a time of economic crisis, enhances the significance of intergenerational solidarity within families. We conclude by calling for research that is attuned to age/generation, gender and class, and how these operate across the family and societal levels.
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The mechanical behavior of microfibrilar composites (MFC), consisting of a matrix of high-density polyethylene (HDPE) and reinforcement of polyamide 6 (PA6) fibrils, with and without compatibilization, was studied. The composites were produced by conventional processing techniques with various shape and arrangement of the PA6 reinforcing entities: long, unidirectional, or crossed bundles of fibrils (UDP and CPC, respectively), middle-length, randomly oriented bristles (MRB), or non-oriented micrometric PA6 spheres (NOM). The tensile, flexural, and impact properties of the MFC materials (UDP, CPC, and MRB) were determined as a function of the PA6 reinforcement shape, alignment and content, and compared with those of NOM, the non-fibrous composite. It was concluded that the in-situ MFC materials based on HDPE/PA6 blends display improvements in the mechanical behavior when compared with the neat HDPE matrix, e.g., up to 33% for the Young modulus, up to 119% for the ultimate tensile strength, and up to 80% for the flexural stiffness. Copyright © 2011 Society of Plastics Engineers.
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Individualism continues to have a notable impact on social work. The personalisation of services and the individualisation of care are just two examples of this societal trend. While helping service users to articulate their aspirations for a better future, individualism, if taken too far, undermines the social aspects of life. In response to this concern, this paper argues that social work must appreciate the interplay between the individual and the collective spheres, and its impact on identity formation, in order to enhance human well-being. To give substance to this argument, Jenkins's model of social identity is appropriated and augmented to take account of four interlinked, yet distinct, orders of experience, namely the individual, interactional, institutional and societal orders. This reworked conceptualisation is then considered in terms of its implications for social work practice.
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Although the international obligations and institutional frameworks for disaster response are not yet settled, as evidenced by the International Law Commission’s work on the protection of persons in the event of disasters and the on-going promotion of disaster laws by the Red Cross Movement; the diverse source and nature of such initiatives suggests that the international community is engaged in a process of norm creation, elaboration and interpretation reflecting a desire for legal clarity in humanitarian operations. Situated within the framework of transnational law, this paper argues that an acquis humanitaire, based on the principle of humanity, encapsulates the evolving body of law and practice specifically relating to the protection of persons in times of humanitarian crisis in both armed conflicts and natural or human-made disasters. Reflecting the non-traditional, non-statist, dynamic and normative basis of transnational legal process, as elaborated by Harold Koh, the constant flow of ideas and principles between the national, regional and international spheres provides an analytical framework for the on-going transnational dialogues on the social, political and legal internalization of humanitarian norms. Drawing on the internalization of humanitarian norms within the United Kingdom, this paper concludes that as the international community examines the codification of a universal legal framework for the protection of persons in the event of disasters it is necessary to understand the transnational process of interpretation and internalization of humanitarian norms, and how this may vary across different regions and countries.
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Silks are protein-based fibers made by arthropods for a variety of task-specific applications. In this article, we review the key features of silk proteins. This article initially focuses on the structure and function of silk proteins produced naturally by silkworms and spiders, followed by the biological and technical processing of silk proteins into a variety of morphologies (including capsules, fibers, films, foams, gels and spheres). Finally, we highlight the potential applications of silk-based materials.
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Social work in the United Kingdom remains embroiled in concerns about child protection error. The serious injury or death of vulnerable children continues to evince much consternation in the public and private spheres. Governmental responses to these concerns invariably draw on technocratic solutions involving more procedures, case management systems, information technology and bureaucratic regulation. Such solutions flow from an implicit use of instrumental rationality based on a ‘means-end’ logic. While bringing an important perspective to the problem of child protection error, instrumental rationality has been overused limiting discretion and other modes of rational inquiry. This paper argues that the social work profession should apply an enlarged form of rationality comprising not only the instrumental-rational mode but also the critical-rational, affective-rational and communicative-rational forms. It is suggested that this combined, conceptual arsenal of rational inquiry leads to a gestalt which has been termed the holistic-rational perspective. It is also argued that embracing a more rounded perspective such as this might offer greater opportunities for reducing child protection error.