651 research outputs found

    Radiation effects on beta 10.6 of pure and europium doped KCl

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    Changes in the optical absorption coefficient as a result of X-ray and electron bombardment of pure KCl (monocrystalline and polycrystalline), and divalent europium doped polycrystalline KCl were determined. The optical absorption coefficients were measured by a constant heat flow calorimetric method. Both 300 KV X-irradiation and 2 MeV electron irradiation produced significant increases in beta 10.6, measured at room temperature. The X-irradiation of pure moncrystalline KCl increased beta 10.6 by 0.005/cm for a 113 MR dose. For an equivalent dose, 2 MeV electrons were found less efficient in changing beta 10.6. However, electron irradiation of pure and Eu-doped polycrystalline KCl produced marked increases in adsorption. Beta increased to over 0.25/cm in Eu-doped material for a 30 x 10 to the 14th power electrons/sq cm dose, a factor of 20 increase over unirradiated material. Moreover, bleaching the electron irradiated doped KCl with 649 m light produced and additional factor of 1.5 increase. These findings will be discussed in light of known defect-center properties in KCl

    Benjamin F. Smith Correspondence

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    Entry is a typed letter on Writers Press Association stationery from William J. Hartford to the Kennebec Public Library, presenting a booklet of an interview with Smith

    The Machine Speaks: Conversational AIs and the importance of effort to relationships of meaning

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    The focus of debates about conversational AIs (CAIs) has largely been on social and ethical concerns that arise when we speak to machines. What is gained and what is lost when we replace our human interlocutorsā€”including our human therapistsā€” with AIs? Here, we focus instead on a distinct and growing phenomenon: letting machines speak for us. What is at stake when we replace our own efforts at interpersonal engagement with CAIs? The purpose of these technologies is, in part, to remove effort. But effort also has enormous value, and in some cases even intrinsic value. This is true in many realms, but especially in interpersonal relationships. To make an effort for someone, irrespective of what that effort amounts to, often conveys value and meaning in itself. We elaborate on the meaning, worth and significance that may be lost when we relinquish effort in our interpersonal engagements, and also on the opportunities for self-understanding and growth that we may forsake

    Addiction, Autonomy, and the Internet: Some ethical considerations

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    Despite growing understanding of the addictive qualities of the internet, and rising concerns about the effects of excessive internet use on personal wellbeing and mental health, the corresponding ethical debate is still in its infancy, and many of the relevant philosophical and conceptual frameworks are underdeveloped. Our goal in this chapter is to explore some of this evolving terrain. While there are unique ethical considerations that pertain to the formalisation of a disorder related to excessive internet use, our ethical concerns (and indeed our mental health concerns) about whether certain technologies undermine wellbeing can and should be far broader than the debates about the appropriateness of particular diagnostic categories. In this chapter we introduce some of these wider debates with regards to persuasive digital technologiesā€” particularly those which aim to maximise use, or even to encourage compulsive engagementā€”as well as the difficulty in articulating the harms involved in excessive internet use, especially where such use has not led to functional impairment. Following these conversations we briefly consider some more practical ethical implications, including regulation of certain design features, concerns about growing socioeconomic inequality in online services, and whether there should be a ā€œright to disconnect.

    Origin of the Ļ• āˆ¼ Ā±9Ā° peaks in YBa2Cu3O7āˆ’Ī“ films grown on cubic zirconia substrates

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    The c-axis oriented YBa2Cu3O7āˆ’Ī“ films grown on (001) yttria-stabilized cubic zirconia (YSZ) substrates often contain domains whose in-plane alignment is rotated approximately 9Ā° from the cube-on-cube epitaxial relationship, in addition to the more commonly observed 0Ā° and 45Ā° in-plane rotations. We have investigated the origin of this āˆ¼9Ā° orientation using in situ electron diffraction during growth and ex situ 4-circle x-ray diffraction. Our results indicate that the āˆ¼9Ā° orientation provides the most favorable lattice match between the interfacial (110)-oriented BaZrO3 epitaxial reaction layer, which forms between YBa2Cu3O7āˆ’Ī“ and the YSZ substrate. If epitaxy occurs directly between YBa2Cu3O7āˆ’Ī“ and the YSZ substrate, i.e., before the BaZrO3 epitaxial reaction layer is formed, the 0Ā° and 45Ā° domains have the most favorable lattice match. However, growth conditions that favor the formation of the BaZrO3 reaction layer prior to the nucleation of YBa2Cu3O7āˆ’Ī“ lead to an increase in āˆ¼9Ā° domains. The observed phenomenon, which results from epitaxial alignment between the diagonal of a square surface net and the diagonal of a rectangular surface net, is a general method for producing in-plane misorientations, and has also been observed for the heteroepitaxial growth of other materials, including (Ba, K)BiO3/LaAlO3. The YBa2Cu3O7āˆ’Ī“/YSZ case involves epitaxial alignment between [111]BaZrO3 and [110]YSZ, resulting in an expected in-plane rotation of 11.3Ā° to 9.7Ā° for fully commensurate and for fully relaxed (110)BaZrO3 on (001)YSZ, respectivel

    Attentional Harms and Digital Inequalities

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    Recent years have seen growing public concern about the effects of persuasive digital technologies on public mental health and well-being. As the draws on our attention reach such staggering scales and as our ability to focus our attention on our own considered ends erodes ever further, the need to understand and articulate what is at stake has become pressing. In this ethical viewpoint, we explore the concept of attentional harms and emphasize their potential seriousness. We further argue that the acknowledgment of these harms has relevance for evolving debates on digital inequalities. An underdiscussed aspect of web-based inequality concerns the persuasions, and even the manipulations, that help to generate sustained attentional loss. These inequalities are poised to grow, and as they do, so will concerns about justice with regard to the psychological and self-regulatory burdens of web-based participation for different internet users. In line with calls for multidimensional approaches to digital inequalities, it is important to recognize these potential harms as well as to empower internet users against them even while expanding high-quality access

    DynGFN: Towards Bayesian Inference of Gene Regulatory Networks with GFlowNets

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    One of the grand challenges of cell biology is inferring the gene regulatory network (GRN) which describes interactions between genes and their products that control gene expression and cellular function. We can treat this as a causal discovery problem but with two non-standard challenges: (1) regulatory networks are inherently cyclic so we should not model a GRN as a directed acyclic graph (DAG), and (2) observations have significant measurement noise, so for typical sample sizes there will always be a large equivalence class of graphs that are likely given the data, and we want methods that capture this uncertainty. Existing methods either focus on challenge (1), identifying cyclic structure from dynamics, or on challenge (2) learning complex Bayesian posteriors over DAGs, but not both. In this paper we leverage the fact that it is possible to estimate the "velocity" of gene expression with RNA velocity techniques to develop an approach that addresses both challenges. Because we have access to velocity information, we can treat the Bayesian structure learning problem as a problem of sparse identification of a dynamical system, capturing cyclic feedback loops through time. Since our objective is to model uncertainty over discrete structures, we leverage Generative Flow Networks (GFlowNets) to estimate the posterior distribution over the combinatorial space of possible sparse dependencies. Our results indicate that our method learns posteriors that better encapsulate the distributions of cyclic structures compared to counterpart state-of-the-art Bayesian structure learning approaches

    Enhancement and Hyperresponsibility

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    We routinely take diminished capacity as diminishing moral responsibility (as in the case of immaturity, senility, or particular mental impairments). The prospect of enhanced capacity therefore poses immediate questions with regard to moral responsibility. Of particular interest are those capacities that might allow us to better avoid serious harms or wrongdoing. We can consider questions of responsibility with regards to enhancement at various removes. In the first instance: where such (safe and effective) interventions exist, do we have an obligation to undergo such enhancement? Secondly: once enhanced, would the ambit of our responsibility therefore increase? Some philosophers have argued that enhanced capacities potentially generate ā€œhyperresponsibility.ā€ Hyperresponsible people would be held to a different and higher moral standard than those of us with more ordinary human capacities, and are liable to be more blameworthy for wrongdoing than ordinary agents. This chapter discusses the implications of enhancement for three central views of responsibility, namely: capacity-based, control-based and revelation-based views. Debates around moral responsibility have primarily concerned diminished capacities; as such the prospect of enhancement introduces new terrainā€”and potentially new fault-lines and complexitiesā€”in which to interrogate our theoretical conceptions of the foundations (and limits) of moral responsibility

    Entitled to Love: Relationships, Commandability and Obligation

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    The notion of uncommandability has been central to how we perceive our emotional lives, and particularly romantic love. According to this notion: while we can control how we treat people, we have little control over how we feel about them. The argument from uncommandability is often evoked as a way of sidestepping moral obligations regarding our romantic emotions. One challenge to uncommandability is the potential to manipulate our emotions through psychopharmaceuticals. Much of the debate on so-called ā€œlove drugsā€ has concerned the permissibility and worth of these interventions. By comparison, less has been explored about their implications for moral obligation and responsibility. How might the emergence of these interventions change what can be emotionally demanded of us? We ultimately suggest that it is necessary to view the complex morality of our emotional lives through different evaluative paradigms: one concerning moral duty and obligation, where we have no claim to each otherā€™s romantic love irrespective of its commandability, and the other concerning the appropriateness of our reactive attitudes, where we are at times justified in feeling morally injured by another person on account of their failure to love us, regardless of whether they had control in the matter

    Dislocation constriction and cross-slip in Al and Ag: an ab initio study

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    A novel model based on the Peierls framework of dislocations is developed. The new theory can deal with a dislocation spreading at more than one slip planes. As an example, we study dislocation cross-slip and constriction process of two fcc metals, Al and Ag. The energetic parameters entering the model are determined from ab initio calculations. We find that the screw dislocation in Al can cross-slip spontaneously in contrast with that in Ag, which splits into partials and cannot cross-slip without first being constricted. The dislocation response to an external stress is examined in detail. We determine dislocation constriction energy and critical stress for cross-slip, and from the latter, we estimate the cross-slip energy barrier for the straight screw dislocations
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