Improving photon-hadron discrimination based on cosmic ray surface detector data

The search for photons at EeV energies and beyond has considerable astrophysical interest and will remain one of the key challenges for ultra-high energy cosmic ray (UHECR) observatories in the near future. Several upper limits to the photon flux have been established since no photon has been unambiguously observed up to now. An improvement in the reconstruction efficiency of the photon showers and/or better discrimination tools are needed to improve these limits apart from an increase in statistics. Following this direction, we analyze in this work the ability of the surface parameter Sb, originally proposed for hadron discrimination, for photon search. Semi-analytical and numerical studies are performed in order to optimize Sb for the discrimination of photons from a proton background in the energy range from 10^18.5 to 10^19.6 eV. Although not shown explicitly, the same analysis has been performed for Fe nuclei and the corresponding results are discussed when appropriate. The effects of different array geometries and the underestimation of the muon component in the shower simulations are analyzed, as well as the Sb dependence on primary energy and zenith angle.Comment: 9 pages, 19 Figures. Accepted in Astroparticle Physics on May 31th, 201

Servitization strategies from customers’ perspective: the moderating role of co-creation

© 2018, Emerald Publishing Limited. Purpose: This paper aims to investigate the moderating role of co-creation in the implementation of servitization strategies in the pharmaceutical industry in a business-to-business (B-to-B) context. More specifically, this investigation explores the impact of different levels of services (base, intermediate and advanced) on servitization and on performance by using co-creation as a moderating factor. Design/methodology/approach: A research framework was developed and empirically tested in the pharmaceutical sector. Data collection was conducted through the online distribution of questionnaires. The final sample included 219 pharmacy stores, and the data were analysed using structural equation modelling. Findings: Main findings suggest that when the level of co-creation of the design of services is high, there are significant effects of servitization on firm performance. The moderating effect of co-creation is illustrated in regard to intermediate and advanced services, but results referring to the impact of intermediate services on servitization appear non-significant with a low degree of co-creation. No significant effects could be found for the impact of base services on performance and servitization for both high and low degrees of co-creation. Findings show an impact of advanced services on performance through the mediating effect of servitization when the degree of co-creation is high. Originality/value: Most research concerning servitization has been done from the perspective of manufacturers and service providers. This study adds value to the literature because it was designed from a customer’s perspective. Moreover, it contributes towards the conceptualization of the servitization research strategy and business models in a B2B context. This is accomplished through the investigation of the moderating effect of co-creation on the impact of the different levels of services on servitization and on performance

Interfollicular epidermal stem cells: boosting and rescuing from adult skin

Publicado na série "Methods in Molecular Biology", vol. 989 (2013), ISSN 1064-3745Epidermal stem cells isolation struggle remains, mainly due to the yet essential requirement of well-defined approaches and markers. The herein proposed methodology integrates an assemblage of strategies to accomplish the enrichment of the interfollicular epidermal stem cells multipotent fraction and their subsequent separation from the remaining primary human keratinocytes culture. Those include rapid adherence of freshly isolated human keratinocytes to collagen type IV through the β 1-integrin ligand and Rho- Associated Protein Kinase Inhibitor Y- 27632 administration to the cultures, followed by an immunomagnetic separation to obtain populations based in the combined CD49f bri /CD71 dim expression. Flow cytometry is the supporting method to analyze the effect of the treatments over the expression rate of early epidermal markers keratins19/5/14 and in correlation to CD49f bri /CD71 dim subpopulations. The stepby- step methodology herein described indulges the boosting and consecutive puri fi cation and separation of interfollicular epidermal stem cells from human keratinocytes cultures.(undefined

Experiência no curso de estudantes de 1º ano – um estudo no âmbito das tutorias de acompanhamento na Universidade de Évora

O presente estudo pretende conhecer a experiência no curso de estudantes de 1º ano que ingressaram na Universidade de Évora no final do 1º semestre. Estudos realizados sobre a percepção dos estudantes relativa ao contexto de aprendizagem no ensino superior indicam forte relação com as abordagens à aprendizagem e apresentam forte relevância para a compreensão da forma como os estudantes acedem ao conhecimento e para a definição de processos de aprendizagem de elevada qualidade (Entwistle, 2009; Chaleta & Entwistle, 2011). Os dados foram obtidos através da aplicação do CEQP (Ramsden, 2005; 2006; Chaleta et al, 2012) com 565 estudantes de diferentes cursos e áreas científicas. Os resultados indicaram que a experiência no curso é positiva para o conjunto dos estudantes havendo necessidade de observar com mais atenção as questões relacionadas com a avaliação. A grande maioria dos estudantes revela também satisfação com o curso que frequenta. Palavras-Chave: Experiência no Curso; Tutorias de Acompanhamento; CEQP; Ensino Superior. Abstract This study examine the experience in the course of the 1st year students who entered at the University of Évora. Studies on the perception of students on the learning environment in higher education indicate a strong relationship with the approaches to learning and have strong relevance to the understanding how students access the knowledge and the definition of high quality learning processes (Entwistle, 2009; Chaleta & Entwistle, 2011). The data were obtained by applying the CEQP (Ramsden, 2005, 2006; Chaleta et al, 2012) with 565 students from different courses and scientific areas. The results indicated that the course experience is positive for all the students but we need to look more closely at the issues related to assessment. The vast majority of students also reveals satisfaction with the course who attends Keywords: Course Experience; Mentor Monitoring; CEQP; Higher Education

Using LDGM Codes and Sparse Syndromes to Achieve Digital Signatures

In this paper, we address the problem of achieving efficient code-based digital signatures with small public keys. The solution we propose exploits sparse syndromes and randomly designed low-density generator matrix codes. Based on our evaluations, the proposed scheme is able to outperform existing solutions, permitting to achieve considerable security levels with very small public keys.Comment: 16 pages. The final publication is available at springerlink.co

An in vivo permeability test protocol using iohexol to reduce and refine the use of laboratory rats in intestinal damage assessment

Assessment of intestinal damage in laboratory rats with experimentally-induced enteropathies is usually carried out by collecting and morphological interpreting tissue samples obtained surgically, endoscopically or at necropsy. Alternatively, changes in the gut mucosa may be less invasively evaluated with intestinal permeability (IP) tests. In contrast to human and veterinary patients, IP test protocols in laboratory rats have been highly variable, which may account for the limited use of this approach by investigators when evaluating intestinal damage. The objective of this study was to establish a refined IP test protocol using iohexol in rats that is able to differentiate between healthy rats and individuals with enteropathies. Iohexol was administered by oral gavage to twenty-eight Sprague-Dawley rats, before and after the induction of inflammatory bowel disease (IBD) with dextran sulphate sodium (DSS). Urine was cumulatively recovered during 24 h, and the presence of iohexol was measured by high-performance liquid chromatography with ultraviolet detection. The median percentage (and interquartile range) of administered iohexol in urine of healthy rats was 0.54% (0.3

Selective cell recruitment and spatially controlled cell attachment on instructive chitosan surfaces functionalized with antibodies

Bioactive constructs to guide cellular mobilization and function have been proposed as an approach for a new generation of biomaterials in functional tissue engineering. Adult mesenchymal stem cells have been widely used as a source for cell based therapeutic strategies, namely tissue engineering. This is a heterogeneous cell population containing many subpopulations with distinct regenerative capacity. Thus, one of the issues for the effective clinical use of stem cells in tissue engineering is the isolation of a highly purified, expandable specific subpopulation of stem cells. Antibody functionalized biomaterials could be promising candidates to isolate and recruit specific cell types. Here we propose a new concept of instructive biomaterials that are able to recruit and purify specific cell types from a mixed cell population. This biomimetic concept uses a target-specific chitosan substrate to capture specific adipose derived stem cells. Specific antibodies were covalently immobilized onto chitosan membranes using bis[sulfosuccinimidyl] suberate (BS3). Quartz crystal microbalance (QCM) was used to monitor antibody immobilization/adsorption onto the chitosan films. Specific antibodies covalently immobilized kept their bioactivity and captured specific cell types from a mixed cell population. Microcontact printing allowed to covalently immobilize antibodies in patterns and simultaneously a spatial control in cell attachmentThe authors acknowledge the Portuguese Foundation for Science and Technology (FCT) for the fellowships SFRH/BD/61390/2009 (C.A.C) and SFRH/BPD/45206/2008 (A.M.F), and also to the International Max-Planck-Research School (C.A.C) for the financial support. We are grateful to Hospital da Prelada for the donations. This work was carried out under the scope of the EU 7th Framework Programme (FP7/2007-2013) under grant agreement no. NMP4-SL-2009-229292 (Find&Bind)

Stochastics theory of log-periodic patterns

We introduce an analytical model based on birth-death clustering processes to help understanding the empirical log-periodic corrections to power-law scaling and the finite-time singularity as reported in several domains including rupture, earthquakes, world population and financial systems. In our stochastics theory log-periodicities are a consequence of transient clusters induced by an entropy-like term that may reflect the amount of cooperative information carried by the state of a large system of different species. The clustering completion rates for the system are assumed to be given by a simple linear death process. The singularity at t_{o} is derived in terms of birth-death clustering coefficients.Comment: LaTeX, 1 ps figure - To appear J. Phys. A: Math & Ge