Gibbs states over the cone of discrete measures

We construct Gibbs perturbations of the Gamma process on \mathbbm{R}^d, which may be used in applications to model systems of densely distributed particles. First we propose a definition of Gibbs measures over the cone of discrete Radon measures on \mathbbm{R}^d and then analyze conditions for their existence. Our approach works also for general L\'evy processes instead of Gamma measures. To this end, we need only the assumption that the first two moments of the involved L\'evy intensity measures are finite. Also uniform moment estimates for the Gibbs distributions are obtained, which are essential for the construction of related diffusions. Moreover, we prove a Mecke type characterization for the Gamma measures on the cone and an FKG inequality for them.Comment: Keywords: Gamma process, Poisson point process, discrete Radon measures, Gibbs states, DLR equation, Mecke identity, FK

Faster computation of the Tate pairing

This paper proposes new explicit formulas for the doubling and addition step in Miller's algorithm to compute the Tate pairing. For Edwards curves the formulas come from a new way of seeing the arithmetic. We state the first geometric interpretation of the group law on Edwards curves by presenting the functions which arise in the addition and doubling. Computing the coefficients of the functions and the sum or double of the points is faster than with all previously proposed formulas for pairings on Edwards curves. They are even competitive with all published formulas for pairing computation on Weierstrass curves. We also speed up pairing computation on Weierstrass curves in Jacobian coordinates. Finally, we present several examples of pairing-friendly Edwards curves.Comment: 15 pages, 2 figures. Final version accepted for publication in Journal of Number Theor

Rumination in PTSD as well as in Traumatized and Non-Traumatized Depressed Patients: A Cross-Sectional Clinical Study

Background: Although rumination is a key process in the onset and maintenance of depressive symptoms and a powerful predictor of persistent posttraumatic stress disorder (PTSD), little is known about the differences and similarities of rumination in these conditions. Previous research has not always differentiated between rumination and intrusive images. Aims: We sought to systematically evaluate rumination and to gather more information about the content and associated emotions in three patient groups (PTSD, and depressed with and without trauma; n = 65). Furthermore, we examined the interaction between rumination and another predominant intrusive cognition, intrusive image. Method: A multi-method assessment for rumination, including a rumination questionnaire and a rumination log (kept for one week), was employed. Results: Rumination was found to be complex and composed of subcomponents that are similar across the diagnostic groups. Rumination rarely stopped intrusive images and it made the participants feel worse. There were, however, also important differences: in PTSD, rumination always or often triggered intrusive images and the traumatized individuals (PTSD and depressed with trauma) ruminated more than non-traumatized depressed patients. Conclusions: The results corroborate the assumption of rumination being a transdiagnostic process, with similarities but also with important differences across diagnostic groups. Moreover, the findings support recent research on the intricate relationship between different types of intrusive cognition

Sector coupling of renewable energy in an experimental setting: findings from a smart energy pilot project in Austria

The integration of previously unconnected sectors of the energy system is considered one of the most important strategies for reducing CO2 emissions. Many studies on technological innovations that deal with the transition to a sustainable energy system focus on innovation niches as a favorable environment within which new solutions can be tested and made ready for the market. This paper examines how protection in such a niche, in combination with organizational path dependency, supports the integration of renewable energy in residential buildings. The results presented are based on a case study on the integration of the electricity, heat, and gas sectors in a housing pilot project, in which local energy needs are met and electricity is fed into the grid in a flexible way. Our findings indicate that favorable conditions for inter-sectoral innovation can be achieved through niche protection, complemented by path dependency in organizational routines and culture.Die Integration von bisher nicht miteinander verbundenen Sektoren des Energiesystems gilt als eine der wichtigsten Strategien zur Reduktion von CO2-Emissionen. Viele Studien zu technischen Innovationen, die sich mit dem Übergang zu einem nachhaltigen Energiesystem befassen, konzentrieren sich auf Innovationsnischen als ein förderliches Umfeld, in dem neue Lösungen getestet und zur Marktreife gebracht werden können. Im vorliegenden Beitrag wird untersucht, wie der Schutz in einer solchen Nische in Kombination mit bestehenden Pfadabhängigkeiten die Integration erneuerbarer Energien bei Wohngebäuden begünstigt. Die Ergebnisse basieren auf einer Fallstudie zur Integration der Sektoren Strom, Wärme und Gas in einem Pilotprojekt, bei dem der lokale Energiebedarf gedeckt und flexibel Strom in das Netz einspeist wird. Unsere Ergebnisse deuten darauf hin, dass förderliche Bedingungen für intersektorale Innovation durch Schutz in der Nische, ergänzt durch Pfadabhängigkeit in Organisationsroutinen und Organisationskultur, gewährleistet werden können

Dark Stars: Improved Models and First Pulsation Results

We use the stellar evolution code MESA to study dark stars. Dark stars (DSs), which are powered by dark matter (DM) self-annihilation rather than by nuclear fusion, may be the first stars to form in the Universe. We compute stellar models for accreting DSs with masses up to 10^6 M_{sun}. The heating due to DM annihilation is self-consistently included, assuming extended adiabatic contraction of DM within the minihalos in which DSs form. We find remarkably good overall agreement with previous models, which assumed polytropic interiors. There are some differences in the details, with positive implications for observability. We found that, in the mass range of 10^4 -10^5 M_{sun}, our DSs are hotter by a factor of 1.5 than those in Freese et al.(2010), are smaller in radius by a factor of 0.6, denser by a factor of 3 - 4, and more luminous by a factor of 2. Our models also confirm previous results, according to which supermassive DSs are very well approximated by (n=3)-polytropes. We also perform a first study of dark star pulsations. Our DS models have pulsation modes with timescales ranging from less than a day to more than two years in their rest frames, at z ~ 15, depending on DM particle mass and overtone number. Such pulsations may someday be used to identify bright, cool objects uniquely as DSs; if properly calibrated, they might, in principle, also supply novel standard candles for cosmological studies.Comment: 17 pages; 11 figures; revised version; accepted by Ap

Reflective equilibrium is enough: against the need for preselecting considered judgements

Neste artigo focamo-nos num elemento controverso do método do equilíbrio reflexivo, nomeadamente a ideia de Rawls de que os compromissos que entram no processo justificatório deveriam ser pré-seleccionados ou filtrados: de acordo com Rawls, apenas os juízos bem ponderados deveriam ser levados em conta na filosofia moral. Os críticos deste processo de filtragem distribuem-se por dois campos: 1) Os críticos do equilíbrio reflexivo rejeitam o processo de filtragem rawlsiano por ser excessivamente fraco e procuram um que seja mais fiável e que constituiria um diferente método epistémico; 2) Os proponentes do equilíbrio reflexivo rejeitam o processo de filtragem Rawlsiano por ser excessivamente excludente. Nós defendemos o ER, em oposição aos seus críticos, argumentando que este método pode assegurar compromissos razoáveis sem estar dependente de um processo externo forte de filtragem. No entanto, alinhamo-nos com os proponentes críticos do equilíbrio reflexivo, defendendo que, sem este processo de filtragem fraco, o ER rawlsiano revela-se como mais plausível tanto como um método geral, como no contexto da filosofia moral.In this paper, we focus on one controversial element of the method of reflective equilibrium, namely Rawls’ idea that the commitments that enter the justificatory procedure should be pre-selected or filtered: According to him, only considered judgements should be taken into account in moral philosophy. There are two camps of critics of this filtering process: 1) Critics of reflective equilibrium: They reject the Rawlsian filtering process as too weak and seek a more reliable one, which would actually constitute a distinct epistemic method. 2) Proponents of reflective equilibrium: They reject the Rawlsian filtering process as too exclusionary. We defend RE against its critics, arguing that the method can secure reasonable commitments without depending on a strong external filtering process. However, we side with the critical proponents of reflective equilibrium and argue that without the Rawlsian weak filtering process, RE is more plausible both as a general method as well as in the context of moral philosophy

The relevance internet users assign to algorithmic-selection applications in everyday life

The rapidly growing academic and public attention to algorithmic-selection applications such as search engines and social media is indicative of their alleged great social relevance and impact on daily life in digital societies. To substantiate these claims, this paper investigates the hitherto little explored subjective relevance that Internet users assign to algorithmic-selection applications in everyday life. A representative online survey of Internet users comparatively reveals the relevance that users ascribe to algorithmic-selection applications and to their online and offline alternatives in five selected life domains: political and social orientation, entertainment, commercial transactions, socializing and health. The results show that people assign a relatively low relevance to algorithmic-selection applications compared to offline alternatives across the five life domains. The findings vary greatly by age and education. Altogether, such outcomes complement and qualify assessments of the social impact of algorithms that are primarily and often solely based on usage data and theoretical considerations

Using a Mixed IRT Model to Assess the Scale Usage in the Measurement of Job Satisfaction

This study investigated the adequacy of a rating scale with a large number of response categories that is often used in panel surveys for assessing diverse aspects of job satisfaction. An inappropriate scale usage is indicative of overstraining respondents and of diminished psychometric scale quality. The mixed Item Response Theory (IRT) approach for polytomous data allows exploring heterogeneous patterns of inappropriate scale usage in form of avoided categories and response styles. In this study, panel data of employees (n = 7036) on five aspects of job satisfaction measured on an 11-point rating scale within the “Household, Income and Labor Dynamics in Australia” (wave 2001) were analyzed. A three-class solution of the restricted mixed generalized partial credit model fit the data best. The results showed that in no class the 11-point scale was appropriately used but that the number of categories used was reduced in all three classes. Respondents of the large class (40%) appropriately differentiate between up to six categories. The two smaller classes (33 and 27%) avoid even more categories and show some kind of extreme response style. Furthermore, classes differ in socio-demographic and job- related factors. In conclusion, a two- to six-point scale without the middle point might be more adequate for assessing job satisfaction