Quantum evolution of scalar fields in Robertson-Walker space-time

We study the $\lambda \phi^4$ field theory in a flat Robertson-Walker space-time using the functional Sch\"odinger picture. We introduce a simple Gaussian approximation to analyze the time evolution of pure states and we establish the renormalizability of the approximation. We also show that the energy-momentum tensor in this approximation is finite once we consider the usual mass and coupling constant renormalizations.Comment: Revtex file, 19 pages, no figures. Compressed ps version available at http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-912.ps.Z or at ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-912.ps.

Phases of granular segregation in a binary mixture

We present results from an extensive experimental investigation into granular segregation of a shallow binary mixture in which particles are driven by frictional interactions with the surface of a vibrating horizontal tray. Three distinct phases of the mixture are established viz; binary gas (unsegregated), segregation liquid and segregation crystal. Their ranges of existence are mapped out as a function of the system's primary control parameters using a number of measures based on Voronoi tessellation. We study the associated transitions and show that segregation can be suppressed is the total filling fraction of the granular layer, $C$, is decreased below a critical value, $C_{c}$, or if the dimensionless acceleration of the driving, $\gamma$, is increased above a value $\gamma_{c}$.Comment: 12 pages, 12 figures, submitted to Phys. Rev.

Universal velocity distributions in an experimental granular fluid

We present experimental results on the velocity statistics of a uniformly heated granular fluid, in a quasi-2D configuration. We find the base state, as measured by the single particle velocity distribution $f(c)$, to be universal over a wide range of filling fractions and only weakly dependent on all other system parameters. There is a consistent overpopulation in the distribution's tails, which scale as $f\propto\exp(\mathrm{const.}\times c^{-3/2})$. More importantly, the high probability central region of $f(c)$, at low velocities, deviates from a Maxwell-Boltzmann by a second order Sonine polynomial with a single adjustable parameter, in agreement with recent theoretical analysis of inelastic hard spheres driven by a stochastic thermostat. To our knowledge, this is the first time that Sonine deviations have been measured in an experimental system.Comment: 13 pages, 15 figures, with minor corrections, submitted to Phys. Rev.

Willingness to pay for environmental quality: The effects of pro-environmental behavior, perceived behavior control, environmental activism, and educational level

Environmental quality is one of the major concerns in contemporary societies. The main goal of this research is to investigate citizens’ willingness to pay for environmental quality and whether this propensity differs in line with education level. Structural equation modeling is used to explore the associations between several constructs; specifically, a multigroup analysis is conducted to assess the invariance of two educational level segments. Results suggest that willingness to pay more for environmental quality is positively associated with perceived behavior control and environmental activism. Pro-environmental behavior does not impact willingness to pay for environmental quality but is positively related to perceived behavior control and environmental activism. The relationships between constructs hold true for both groups of education. Implications for public policy and marketing actions are addressed.info:eu-repo/semantics/publishedVersio

Men who suffered intimate partner violence: Impressions about existing public campaigns and recommendations for new ones

Over the last decades, the negative effects of intimate partner violence (IPV) directed at men in abusive different-sex and same-sex relationships have been increasingly investigated. Men who are the targets of IPV face many barriers to help-seeking, and to overcome them, public awareness campaigns have been developed. Women who experienced IPV have found campaigns targeting them to be harmful and misleading, and previous research suggests that following the principles of formative evaluation research may improve campaigns’ effectiveness and reduce unwanted negative effects. This article documents the theory-based formative evaluation research conducted with 14 men abused in different-sex and same-sex relationships for the creation of targeted campaigns. Through semi-structured interviews, men were asked about their overall knowledge of campaigns, their thoughts about specific pictorial IPV campaigns, and their suggestions for the development of new campaigns. Thematic analysis and a theoretically grounded coding scheme were used to analyze the content of the interviews with high inter-rater reliability. Overall, our results indicate that most men were not aware of campaigns in Portugal, and their impressions about the ones they recalled were mixed. Most men praised clear messages informing forms of violence, while some responded negatively to the inclusion of words such as “shame” and “victim”, and the depiction of bruises. They also considered that future campaigns targeting men should portray “real people” like them and provide information on self-efficacy, the efficacy of recommended responses, and threat susceptibility. Our findings are consistent with previous evidence with women who experienced IPV but also provide theoretically grounded novel contributions and highlight the importance of considering the population of interest’s insights when developing and testing new campaigns.info:eu-repo/semantics/publishedVersio

Element characterization of the vestigial shell of Octopus vulgaris Cuvier, 1797

The present study represents the first elemental distribution and composition characterization of the vestigial shell in Octopus vulgaris Cuvier, 1797. Ten specimens of O. vulgaris were collected monthly between January and July 2002, on the central coast of Portugal. Using nuclear microscopy, Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-ray Emission (PIXE) techniques, it was found that along vestigial shell transversal sections, the elemental concentrations were differential. Most striking were those of P, Ca, S, and Cl. At the core of the vestigial shell, high concentration levels of Ca and P were determined, declining towards the periphery. Also, trace concentrations of elements such as Fe, Cu and Zn were found to be higher in the external rings than the inner regions. Future complementary studies of vestigial shell chemical composition, as well as histology studies, are necessary to gain better understanding of the vestigial shell microstructure.Se presenta la primera caracterización de la distribución elemental y de la composición de la concha vestigial del pulpo Octopus vulgaris Cuvier, 1797. Diez muestras de O. vulgaris fueron recogidas mensualmente, entre enero y julio del 2002, en la costa central de Portugal. Utilizando microscopía electrónica, técnicas de espectrometría Rutherford de refracción (RBS) y emisión de rayos X inducida por partículas (PIXE), se pudieron encontrar, a lo largo de las secciones transversales de la concha vestigial, diferencias en las concentraciones elementales, en particular en las de P, Ca, S, y Cl. En el núcleo de la concha vestigial, se pudieron determinar altas concentraciones de Ca y P, que se iban reduciendo hacia la periferia. Asimismo, se encontraron microelementos, como el Fe, Cu y el Zn, a concentraciones que eran mayores en los anillos externos que en las regiones internas. Para una mejor comprensión de la microestructura de la concha vestigial, es necesario llevar a cabo estudios complementarios a éste, y también estudios histológicos.Instituto Español de Oceanografí

Evidence for entanglement at high temperatures in an engineered molecular magnet

The molecular compound [Fe$_{2}$($\mu_{2}$-oxo)(C$_{3}$H$_{4}$N$_{2}$)$_{6}$(C$_{2}$O$_{4}$)$_{2}$] was designed and synthesized for the first time and its structure was determined using single-crystal X-ray diffraction. The magnetic susceptibility of this compound was measured from 2 to 300 K. The analysis of the susceptibility data using protocols developed for other spin singlet ground-state systems indicates that the quantum entanglement would remain at temperatures up to 732 K, significantly above the highest entanglement temperature reported to date. The large gap between the ground state and the first-excited state (282 K) suggests that the spin system may be somewhat immune to decohering mechanisms. Our measurements strongly suggest that molecular magnets are promising candidate platforms for quantum information processing