Current-driven atomic waterwheels

A current induces forces on atoms inside the conductor that carries it. It is now possible to compute these forces from scratch, and to perform dynamical simulations of the atomic motion under current. One reason for this interest is that current can be a destructive force—it can cause atoms to migrate, resulting in damage and in the eventual failure of the conductor. But one can also ask, can current be made to do useful work on atoms? In particular, can an atomic-scale motor be driven by electrical current as it can be by other mechanisms. For this to be possible, the current-induced forces on a suitable rotor must be non-conservative, so that net work can be done per revolution. Here we show that current-induced forces in atomic wires are not conservative and that they can be used, in principle, to drive an atomic-scale waterwheel.

The massive neutron star or low-mass black hole in 2S 0921-630

We report on the optical spectroscopy of the eclipsing halo low-mass X-ray binary 2S 0921-630, which reveals the absorption-line radial velocity curve of the K0 III secondary star with a semiamplitude K-2=92.89+/-3.84 km s(-1), a systemic velocity gamma=34.9+/-3.3 km s(-1), and an orbital period P-orb of 9.0035+/-0.0029 days (1 sigma). Given the quality of the data, we find no evidence for the effects of X-ray irradiation. Using the previously determined rotational broadening of the mass donor and applying conservative limits on the orbital inclination, we constrain the compact object mass to be 2.0-4.3 M-circle dot (1 sigma), ruling out a canonical neutron star at the 99% level. Since the nature of the compact object is unclear, this mass range implies that the compact object is either a low-mass black hole with a mass slightly higher than the maximum possible neutron star mass (2.9 M-circle dot) or a massive neutron star. If the compact object is a black hole, it confirms the prediction of the existence of low-mass black holes, while if the object is a massive neutron star, its high mass severely constrains the equation of state of nuclear matter.

El idiotismo de la sociedad tradicionalista tecnificada de principios de siglo XX en Colombia: La crítica de Luis Vidales a través de "Suenan timbres"

En este artículo tratamos, por medio de Suenan timbres de Luis Vidales, el idiotismo de la sociedad tradicionalista tecnificada de principios de siglo XX en Colombia. Estudio que realizamos desde el concepto de idiotismo de Vidales, en estrecha relación con el de cultura de viñeta de Rafael Gutiérrez Girardot, para plantear la burla del poeta a la sociedad capitalista, que cuestiona la presencia de la Iglesia católica y la política conservadora en todos los estadios de la vida nacional.

Doppler cooling of gallium atoms: 2. Simulation in complex multilevel systems

This paper derives a general procedure for the numerical solution of the Lindblad equations that govern the coherences arising from multicoloured light interacting with a multilevel system. A systematic approach to finding the conservative and dissipative terms is derived and applied to the laser cooling of p-block elements. An improved numerical method is developed to solve the time-dependent master equation and results are presented for transient cooling processes. The method is significantly more robust, efficient and accurate than the standard method and can be applied to a broad range of atomic and molecular systems. Radiation pressure forces and the formation of dynamic dark states are studied in the gallium isotope 66Ga.

Fabricating Economic Development

Much of the literature, regardless of academic discipline, presents the publication of Economic Development in 1958 as analogous to a"big bang" event in the creation of modern Ireland. However, such a "big bang" perspective misrepresents the sophistication of economic debates prior to Whitaker's report as well as distorting the interpretation of subsequent developments. This paper reappraises Irish economic thinking before and after the publication of Economic Development. It is argued that an economically "liberal" approach to Keynesianism, such as that favoured by T. K. Whitaker and George O'Brien, lost out in the 1960s to a more interventionist approach: only later did a more liberal approach to macroeconomic policy triumph. The rival approaches to academic economics were in turn linked to wider debates on the influence of religious authorities on Irish higher education. Academic economists were particularly concerned with preserving their intellectual independence and how a shift to planning would keep decisions on resource allocation out of the reach of conservative political and religious leaders.

Dilemmatic human-animal boundaries in Britain and Romania: Post-materialist and materialist dehumanization

Theories of dehumanization generally assume a single clear-cut, value-free and non-dilemmatic boundary between the categories 'human' and 'animal'. The present study highlights the relevance of dilemmas involved in drawing that boundary. In six focus groups carried out in Romania and Britain, 42 participants were challenged to think about dilemmas pertaining to animal and human life. Four themes were identified: rational autonomy, sentience, speciesism and maintaining materialist and post-materialist values. Sentience made animals resemble humans, while humans' rational autonomy made them distinctive. Speciesism underlay the human participants' prioritization of their own interests over those of animals, and a conservative consensus that the existing social system could not change supported this speciesism when it was challenged. Romanian participants appealed to Romania's lack of modernity and British participants to Britain's modernity to justify such conservatism. The findings suggest that the human-animal boundary is not essentialized; rather it seems that such boundary is constructed in a dilemmatic and post hoc way. Implications for theories of dehumanization are discussed.

Covenanter Politics: Evangelicalism, Political Liberalism and Ulster Presbyterians, 1798-1914

Historians of Ireland have devoted considerable attention to the Presbyterian origins of modern Irish republicanism in the 1790s and their overwhelming support for the Union with Great Britain in the 1880s. On the one hand, it has been argued that conservative politics came to dominate nineteenth-century Presbyterianism in the form of Henry Cooke who combined conservative evangelical religion with support for the established order. On the other hand, historians have long acknowledged the continued importance of liberal and radical impulses amongst Presbyterians. Few historians of the nineteenth century have attempted to bring these two stories together and to describe the relationship between the religion and politics of Presbyterians along the lines suggested by scholars of Presbyterian radicalism in the last quarter of the eighteenth century. This article argues that a distinctive form of Presbyterian evangelicalism developed in the nineteenth century that sought to bring the denomination back to the theological and spiritual priorities of seventeenth-century Scottish and Irish Presbyterianism. By doing so, it encouraged many Presbyterians to get involved in movements for reform and liberal politics. Supporters of ‘Covenanter Politics’ utilised their denominational principles and traditions as the basis for political involvement and as a rhetoric of opposition to Anglican privilege and Catholic tyranny. These could be the prime cause of Presbyterian opposition to the infringement of their rights, such as the marriage controversy and the Disruption of the Church of Scotland in the early 1840s, and they could also be employed as a language of opposition in response to broader social and political developments, such as the demands for land reform stimulated by the agricultural depression that accompanied the Famine. Despite their opposition to ascendancy, however, the Covenanter Politics of Presbyterian Liberals predisposed them towards pan-protestant unionism against the threat of ‘Rome Rule’.

Secularism and Religion in Nineteenth-Century Germany: The Rise of the Fourth Confession

Negotiating the boundaries of the secular and of the religious is a core aspect of modern experience. In mid-nineteenth-century Germany, secularism emerged to oppose church establishment, conservative orthodoxy, and national division between Catholics, Protestants, and Jews. Yet, as historian Todd H. Weir argues in this provocative book, early secularism was not the opposite of religion. It developed in the rationalist dissent of Free Religion and, even as secularism took more atheistic forms in Freethought and Monism, it was subject to the forces of the confessional system it sought to dismantle. Similar to its religious competitors, it elaborated a clear worldview, sustained social milieus, and was integrated into the political system. Secularism was, in many ways, Germany's fourth confession. While challenging assumptions about the causes and course of the Kulturkampf and modern antisemitism, this study casts new light on the history of popular science, radical politics, and social reform.

A 7000 yr perspective on volcanic ash clouds affecting northern Europe

The ash cloud resulting from the 2010 eruption of Eyjafjöll caused severe disruption to air travel across Europe but as a geological event, it is not unprecedented. Analysis of peat and lake sediments from northern Europe has revealed the presence of microscopic layers of Icelandic volcanic ash (tephra). These sedimentary records, together with historical records of Holocene ash falls, demonstrate that Icelandic volcanoes have generated substantial ash clouds that reached northern Europe many times. Here we present the first comprehensive compilation of sedimentary and historical records of ash-fall events in northern Europe, spanning the last 7000 years. Within this period ten tephra layers have been identified in the Faroe Islands, 14 in Great Britain, 11 in Germany, 38 in Scandinavia and 33 in Ireland. Seven ash fall events have been historically documented prior to the Eyjafjöll 2010 event. Ash fall events appear to be more frequent in the last 1500 years, but it is unclear whether this reflects a true increase in eruption frequency or dispersal, or is an artefact of the records themselves or the way they have been generated. In the last 1,000 years, volcanic ash clouds reached Northern Europe with a mean return interval of 53 ± 8 years (the range of return intervals is between 6 and 112 years). Modelling using the ash records for the last millennium indicates that for any 10 year period there is a 17% probability of tephra fallout event in Northern Europe. These values must be considered as conservative estimates due to the nature of tephra capture and preservation in the sedimentary record.

A concept analysis of renal supportive care: the changing world of nephrology

Title. A concept analysis of renal supportive care: the changing world of nephrology

Aim. This paper is a report of a concept analysis of renal supportive care.

Background. Approximately 1.5 million people worldwide are kept alive by renal dialysis. As services are required to support patients who decide not to start or to withdraw from dialysis, the term renal supportive care is emerging. Being similar to the terms palliative care, end-of-life care, terminal care and conservative management, there is a need for conceptual clarity.

Method. Rodgers' evolutionary method was used as the organizing framework for this concept analysis. Data were collected from a review of CINAHL, Medline, PsycINFO, British Nursing Index, International Bibliography of the Social Sciences and ASSIA (1806-2006) using, 'renal' and 'supportive care' as keywords. All articles with an abstract were considered. The World Wide Web was also searched in English utilizing the phrase 'renal supportive care'.

Results. Five attributes of renal supportive care were identified: available from diagnosis to death with an emphasis on honesty regarding prognosis and impact of disease; interdisciplinary approach to care; restorative care; family and carer support and effective, lucid communication to ensure informed choice and clear lines of decision-making.

Conclusion. Renal supportive care is a dynamic and emerging concept relevant, but not limited to, the end phase of life. It suggests a central philosophy underpinning renal service development that allows patients, carers and the multidisciplinary team time to work together to realize complex goals. It has relevance for the renal community and is likely to be integrated increasingly into everyday nephrology practice.

Nonconservative current-induced forces: A physical interpretation

We give a physical interpretation of the recently demonstrated non-conservative nature of interatomic forces in current-carrying nanostructures. We start from the analytical expression for the curl of these forces, and evaluate it for a point defect in a current-carrying system. We obtain a general definition of the capacity of electrical current flow to exert a non-conservative force, and thus do net work around closed paths, by a formal non-invasive test procedure. Second, we show that the gain in atomic kinetic energy in time, generated by non-conservative current-induced forces, is equivalent to the uncompensated stimulated emission of directional phonons. This connection with electron-phonon interactions quantifies explicitly the intuitive notion that non-conservative forces work by angular momentum transfer.

Web crippling behaviour of cold-formed steel channel sections with offset web holes subjected to interior-two-flange loading

Cold-formed steel sections are often used as wall studs or floor joists; such sections often include web holes for ease of installation of the services. Cold-formed steel design codes, however, do not consider the effect of such web holes. In this paper, a combination of experimental tests and non-linear elasto-plastic finite element analyses are used to investigate the effect of such holes on web crippling under interior-two-flange (ITF) loading conditions; the cases of both flange fastened and flange unfastened are considered. A good agreement between the experimental tests and finite element analyses was obtained. The finite element model was then used for the purposes of a parametric study on the effect of different sizes and position of holes in the web. It was demonstrated that the main factors influencing the web crippling strength are the ratio of the hole depth to the depth of the web, and the ratio of the distance from the edge of the bearing to the flat depth of web. Design recommendations in the form of web crippling strength reduction factors are proposed, that are conservative to both the experimental and finite element results.

Comparative tracing experiments to investigate epikarst structural and compositional heterogeneity

Comparative tracer testing may be used to evaluate the vulnerability of groundwater to specific contaminants by comparing reactive tracer response to that of a simultaneously injected non-reactive “conservative” substance. Conversely, knowledge of tracer reaction with specific materials permits information about subsurface heterogeneity to be inferred. A series of tests completed in the vadose zone overlying a limestone aquifer employed a cocktail of particles along with reactive and non-reactive solute tracers to investigate transport rates between the ground surface and monitoring points approximately 10 m below ground. Short pulse tests revealed both solutes and particulate contaminants could travel at rates of over 10 m/h. Comparison of particle (microorganisms) and non-reactive solute tracer breakthrough revealed that particle tracers experience pore exclusion resulting in higher peak relative concentrations which arrive earlier than those of the solute. Prolonged tracer injection during subsequent experiments confirmed the response observed and illustrated that over 40 % of flow paths between injection and monitoring points were inaccessible to particles, but could allow solutes to pass through them. Similarly, the difference in response between various reactive tracers demonstrated tracers reached monitoring points via multiple flow paths and suggests geochemical heterogeneity plays an important role in influencing tracer behaviour. The results of this investigation highlight the complexity of water flow through the epikarst and the vulnerability of groundwater in karst aquifers to contamination when soil cover is thin to absent.

Cold-formed steel sections with web openings subjected to web crippling under two-flange loading conditions - Part II: Parametric study and proposed design equations

A parametric study of cold-formed steel sections with web openings subjected to web crippling was undertaken using finite element analysis, to investigate the effects of web holes and cross-section sizes on the web crippling strengths of channel sections subjected to web crippling under both interior-two-flange (ITF) and end-two-flange (ETF) loading conditions. In both loading conditions, the hole was centred beneath the bearing plate. It was demonstrated that the main factors influencing the web crippling strength are the ratio of the hole depth to the flat depth of the web, and the ratio of the length of bearing plates to the flat depth of the web. In this paper, design recommendations in the form of web crippling strength reduction factors are proposed, that are conservative to both the experimental and finite element results.