Exit times in non-Markovian drifting continuous-time random-walk processes

By appealing to renewal theory we determine the equations that the mean exit time of a continuous-time random walk with drift satisfies both when the present coincides with a jump instant or when it does not. Particular attention is paid to the corrections ensuing from the non-Markovian nature of the process. We show that when drift and jumps have the same sign the relevant integral equations can be solved in closed form. The case when holding times have the classical Erlang distribution is considered in detail.

Self-expandable metal stents in the treatment of acute esophageal variceal bleeding.

Acute variceal bleeding (AVB) is a life-threatening complication in patients with cirrhosis. Hemostatic therapy of AVB includes early administration of vasoactive drugs that should be combined with endoscopic therapy, preferably banding ligation. However, failure to control bleeding or early rebleed within 5 days still occurs in 15-20% of patients with AVB. In these cases, a second endoscopic therapy may be attempted (mild bleeding in a hemodynamically stable patient) or we can use a balloon tamponade as a bridge to definitive derivative treatment (i.e., a transjugular intrahepatic portosystemic shunt). Esophageal balloon tamponade provides initial control in up to 80% of AVB, but it carries a high risk of major complications, especially in cases of long duration of tamponade (>24 h) and when tubes are inserted by inexperienced staff. Preliminary reports suggest that self-expandable covered esophageal metallic stents effectively control refractory AVB (i.e., ongoing bleeding despite pharmacological and endoscopic therapy or massive bleeding precluding endoscopic therapy) with a low incidence of complications. Thus, covered self-expanding metal stents may represent an alternative to the Sengstaken-Blakemore balloon for the temporary control of bleeding in treatment failures. Further studies are required to determine the role of this new device in AVB.

Author Rights vs Self-Archiving in Spanish Scientific Journals

The paper analyzes publishers" copyright policies and self-archiving conditions of Spanish scientific journals. Data are extracted from the directory DULCINEA that contains information of 1318 Spanish journals, of which 775 (61%) allow some form of self-archiving to be about 60% of the post-print version and allowing them 87% of the deposit of the version of record. In 72% of journals the deposit can be performed immediately after publication and in 16% after article acceptance. 72% of the journals are freely available without charge to the user this figure raises up to 86% if free access after an embargo is considered. Only 18% of the journals use Creative Commons licenses. The adoption of different open access journals model in Spain is favorable, however there is still a high percentage of journals (39%) that do not provide any information about authors and publishers rights and that difficult or inhibits reuse of published articles.

Gestión de la actividad no presencial y autoevaluación de competencias = Management of Student Learning Outside the Classroom and the Self-evaluation of Competences

Psychological Assessment is a core subject of Psychology studies, and of the university degree Human development, at the University of Girona and according to the University regulations, had 12 credits. Until the 2005-06 academic years, the student work conducted outside the classroom consisted of undertaking a psychological assessment that was written and handed in at the end of the course. From this the student obtained a qualification and a review if they applied for it In accordance with the European Credits for Higher Education, this subject was reduced to 9 credits, which is the equivalent of a total of 255 hours of in-class work and outside the classroom. In the 2006-07 academic year we created a guide to manage the student’s experiences outside the classroom, with the objective of encouraging the application of problem solving/critical thinking (Bloom, 1975), in line with the recommendations of the Catalonia Agency for University System Quality (2005). The guide includes: learning objectives, evaluation criterions, a description of activities, work week timetable for the whole course, programmed tutorials to review all steps of the psychological assessment process, and the use of a web-based virtual forum for the transfer of knowledge, analysis and constructive critiques of the assessment done by themselves and their colleagues

Persistent random walk model for transport trough thin slabs

We present a model for transport in multiply scattering media based on a three-dimensional generalization of the persistent random walk. The model assumes that photons move along directions that are parallel to the axes. Although this hypothesis is not realistic, it allows us to solve exactly the problem of multiple scattering propagation in a thin slab. Among other quantities, the transmission probability and the mean transmission time can be calculated exactly. Besides being completely solvable, the model could be used as a benchmark for approximation schemes to multiple light scattering.

p-Nitrobenzyloxycarbonyl (pNZ) as Temporary Na-Protecting Group for Mild Solid-Phase Peptide Synthesis. Avoiding Diketopiperazine and Aspartimide Formation

p-Nitrobenzyloxycarbonyl was used as temporary protecting group for the -amino function in solid-phase peptide synthesis. The corresponding derivatives are solids, easy to be synthesized, and perform well in the solid-phase mode. pNZ is removed in practical neutral conditions in the presence of catalytic amounts of acid. They are orthogonal with the most common protecting groups used in peptide chemistry. They are specially useful in combination with Fmoc chemistry to overcome those side reactions associated with the used of the piperidine such DKP and aspartiimide formation. The flexibility of pNZ can be very useful for the preparation of libraries of small organic molecules.

Finding and characterizing Partially Methylated Domains in human haematopoietic cells

DNA cytosine methylation has been demonstrated to be a central epigenetic modification that has essential roles in a myriad of cellular processes. Some examples of these include gene regulation, DNA-protein interactions, cellular differentiation, X-inactivation, maintenance of genome integrity by suppressing transposable elements and viruses, embryogenesis, genomic imprinting and tumourigenesis. This list is increasingly growing thanks to recent advances in genome-wide technologies, like Whole Genome Bisulfite Sequencing (WGBS-Seq). The development of this technology in research has allowed the identification of new features of the DNA methylation landscape that was not possible using previous technologies, like Partially Methylated Domains (PMDs). PMDs have been found in several cell lines, as well as in both healthy and cancer primary samples. They have been described as regions with high variability in methylation levels across individual CpG sites and intermediate methylation levels on average with respect to the genome. Here, we performed an extensive search of PMDs in a big dataset of different haematopoietic primary cells from both myeloid and lymphoid lineages. We found and characterized significant PMDs in plasma B cells, confirming that PMDs are a phenomenon that is restricted to certain differentiated cells. Additionally, we found loci aberrantly hypomethylated in a myeloma sample which overlapped with plasma B cell PMDs. Genome-wide comparison of the myeloma and plasma B cell sample revealed that this is probably also the case for other loci.