Large amplitude pairing fluctuations in atomic nuclei

Pairing fluctuations are self-consistently incorporated on the same footing as the quadrupole deformations in present state of the art calculations including particle number and angular momentum conservation as well as configuration mixing. The approach is complemented by the use of the finite range density dependent Gogny force which, with a unique source for the particle-hole and particle-particle interactions, guarantees a self-consistent interplay in both channels. We have applied our formalism to study the role of the pairing degree of freedom in the description of the most relevant observables like spectra, transition probabilities, separation energies, etc. We find that the inclusion of pairing fluctuations mostly affects the description of excited states, depending on the excitation energy and the angular momentum. $E0$ transition probabilities experiment rather big changes while $E2$'s are less affected. Genuine pairing vibrations are thoroughly studied with the conclusion that deformations strongly inhibits their existence. These studies have been performed for a selection of nuclei: spherical, deformed and with different degree of collectivity.Comment: 23 pages, 23 Figures, To be published in Phys. Rev.

Self-fields in thin superconducting tapes: implications to the thickness effect in coated conductors

Most applications of superconductors, such as power transmission lines, motors, generators, and transformers, require long cables through which large currents circulate. Impressive progress has recently been achieved in the current-carrying capability in conductors based on high-temperature superconductors. Coated conductors are likely the best examples, consisting of very good quality thin layers of YBCO superconductor grown on top of a metallic tape with some intermediate layers. However, there is an important problem for achieving large currents: a large decrease in transport critical-current density Jc when increasing film thickness has been observed in coated conductors made by all available techniques. Here, we theoretically explain the nature and the ubiquitous presence of this so-called thickness effect by analyzing the self-field created by the transport currents in the superconductor, assuming a realistic field-dependent Jc. This knowledge can help finding new ways to improve transport current in thick superconducting films.Comment: 7 pages, 3 figure

Theoretical reflections on narrative in action research

Narrative is an important tool for developing and writing up action research experiences. Its power lies in the fact that narrative construction and narrative recounting are fundamental human communication practices. Narratives are also knowledge producing devices, since they make sense of personal experiences and share that sense-giving with others. However, the twinned duality of narrative knowing (sense-making) and narrative telling (communicating that sense) has often caused narrative as a methodological approach to be disregarded or misunderstood. Our objective is to reflect on how we can best use the narrative method in action research by paying due attention to these issues. In doing so, we consider ontologies, epistemologies and key characteristics. We argue that what has been seen as a weakness in the narrative method, its deep subjectivity, can actually be employed as an analytical strength in action research. We show how examining explanations of context, inherent in narrative processes, can provide rich insights into the meanings of phenomena

Theoretical reflections on narrative in action research.

Narrative is an important tool for developing and writing up action research experiences. Its power lies in the fact that narrative construction and narrative recounting are fundamental human communication practices. Narratives are also knowledge producing devices, since they make sense of personal experiences and share that sense-giving with others. However, the twinned duality of narrative knowing (sense-making) and narrative telling (communicating that sense) has often caused narrative as a methodological approach to be disregarded or misunderstood. Our objective is to reflect on how we can best use the narrative method in action research by paying due attention to these issues. In doing so, we consider ontologies, epistemologies and key characteristics. We argue that what has been seen as a weakness in the narrative method, its deep subjectivity, can actually be employed as an analytical strength in action research. We show how examining explanations of context, inherent in narrative processes, can provide rich insights into the meanings of phenomena

Cox process goodness-of-fit test. A Matlab file.

The Cox Process (CP) models many real phenomena dealing with counting data. Having observed sample paths of a counting process in a discrete set of time points and assuming that the phenomenon can be modeled by a Cox process or compound Cox process, an important task is to decide if those paths fit a given model. A goodnes-of-fit test to assess the coherence of the new observed data with the given Cox process has been proposed by the authors, taking into account if the process is parametrically known or it has to be estimated. This paper deals with a computational tool to support the test.FQM-307, FQM-246, MTM2010-2050

A Matlab tool for Cox Processes with truncated Gaussian mean

The truncated Gaussian distribution rises in many practical situations, the aim of this paper is to give some tools to solve common tasks within this kind of random variables. A modified maximum likelihood estimation of the parameters of the distribution from an observed data set is given, we also implement a goodness-of- t test for a theoretical truncated Gaussian distribution. Finally, if we assume that the mean of a Cox process at each instant of time is distributed as a truncated Gaussian distribution, we give the most probable value of the process at a given time point.FQM347, MTM2010-2050

SPITZER observations of the λ Orionis cluster. II. Disks around solar-type and low-mass stars

We present IRAC/MIPS Spitzer Space Telescope observations of the solar-type and the low-mass stellar population of the young (~5Myr) λ Orionis cluster. Combining optical and Two Micron All Sky Survey photometry, we identify 436 stars as probable members of the cluster. Given the distance (450 pc) and the age of the cluster, our sample ranges in mass from 2 M_⊙ to objects below the substellar limit. With the addition of the Spitzer mid-infrared data, we have identified 49 stars bearing disks in the stellar cluster. Using spectral energy distribution slopes, we place objects in several classes: non-excess stars (diskless), stars with optically thick disks, stars with “evolved disks” (with smaller excesses than optically thick disk systems), and “transitional disk” candidates (in which the inner disk is partially or fully cleared). The disk fraction depends on the stellar mass, ranging from ~6% for K-type stars (R_C − J 4). We confirm the dependence of disk fraction on stellar mass in this age range found in other studies. Regarding clustering levels, the overall fraction of disks in the λ Orionis cluster is similar to those reported in other stellar groups with ages normally quoted as ~5Myr

MMP-2 and sTNF-R1 variability in patients with essential hypertension: 1-year follow-up study

The aim of this study is to analyze MMP-2 and sTNF-R1 variability, potent predictors of cardiovascular events, in stable hypertensive patients during a 12-month followup. 234 asymptomatic patients (age 6 0 ± 1 3 , 136 male) out of 252 patients with essential hypertension were followed up. MMP-2 and sTNF-R1 were measured at baseline and after 12 months (stage I). To compare MMP-2 and sTNF-R1 levels over time interval, we used the statistical method of Bland-Altman. MMP-2 and sTNF-R1 reproducibility was good in our patients for the two intervals with a coefficient of reproducibility of 8.2% and 11.3%, respectively. The percentages of patients within 1.96 × standard deviation of the mean were 93.6% and 92.7%. An elevated coefficient of correlation was obtained for MMP-2, basal versus stage I