Exchange Leavitt path algebras and stable rank

We characterize those Leavitt path algebras which are exchange rings in terms of intrinsic properties of the graph and show that the values of the stable rank for these algebras are 1, 2 or ∞. Concrete criteria in terms of properties of the underlying graph are given for each case

Associations between sedentary time, physical activity and bone health among older people using compositional data analysis

Introduction : Aging is associated with a progressive decrease in bone mass (BM), and being physical active is one of the main strategies to combat this continuous loss. Nonetheless, because daily time is limited, time spent on each movement behavior is co-dependent. The aim of this study was to determine the relationship between BM and movement behaviors in elderly people using compositional data analysis. Methods : We analyzed 871 older people [395 men (76.9 +/- 5.3y) and 476 women (76.7 +/- 4.7y)]. Time spent in sedentary behavior (SB), light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA), was assessed using accelerometry. BM was determined by bone densitometry (DXA). The sample was divided according to sex and bone health indicators. Results : The combined effect of all movement behaviors (PA and SB) was significantly associated with whole body, leg and femoral region BM in the whole sample (p<0.05), with leg and pelvic BM (p<0.05) in men and, with whole body, arm and leg BM (p<0.05) in women. In men, arm and pelvic BM were negatively associated with SB and whole body, pelvic and leg BM were positively associated with MVPA (p<0.05). In women, whole body and leg BM were positively associated with SB. Arm and whole body BM were positively associated and leg BM was negatively associated with LPA and arm BM was negatively associated with MVPA (p<0.05). Women without bone fractures spent less time in SB and more in LPA and MVPA than the subgroup with bone fractures. Conclusion : We identified that the positive effect of MVPA relative to the other behaviors on bone mass is the strongest overall effect in men. Furthermore, women might decrease bone fracture risk through PA increase and SB reduction, despite the fact that no clear benefits of PA for bone mass were found

Generalized granuloma annulare after pneumococcal vaccination

Granuloma annulare may be caused by multiple triggers. Among these are vaccinations, which have been described as an infrequent cause of granuloma annulare. The authors report the first case of generalized granuloma annulare associated with pneumococcal vaccination in a 57-year-old woman, who presented cutaneous lesions 12 days after vaccination

Hidden clear cell acanthoma with uncommon dermoscopic findings

Dear Editor, A 73-year-old woman presented with less than a 1-year history of an erythematous, well-delimited and shiny lesion on her left buttock, near the gluteal fold. Dermoscopic examination showed dotted vessels arranged in a linear pattern involving the entire lesion. These vascular findings are also called metaphorically a ‘string of pearls’ pattern. Another vascular pattern observed on the periphery of the lesion is that of branched vessels with rounded endings. Surprisingly, dermoscopy also revealed multiple rosettes (also known as ‘four-clod dots’). Differential diagnoses included mainly clear cell acanthoma, irritated seborrheic keratosis, Bowen´s disease and eccrine poroma. The lesion was completely surgically removed and histopathologic examination revealed an epidermic lesion with marked psoriasiform hyperplasia, in which epidermal cells show clear cytoplasms (Fig. 3). These findings are consistent with the diagnosis of Clear Cell Acanthoma (CCA)..

La obra de Alfonso Fraile: una aproximación vivencial al concepto contemporáneo del espacio

Este artículo trata de hacer una aproximación a lo que consideramos fue el objetivo de la investigación pictórica de Alfonso Fraile —uno de los máximos representantes de la corriente Nueva Figuración— que consistió, en nuestra opinión, en la búsqueda de recursos para materializar la representación de un espacio fundamentado en la reflexión sobre la propia existencia , que cristaliza en una figuración de extrema subjetividad. Hacia 1986 surge en su obra el concepto de espacio vivencial, basado en la idea de que sólo existe espacio en la medida de que el hombre, que es espacial, lo despliega a su alrededor, creando así su propio entorno.This article attempts to approach what we consider was the purpose of the pictorial research of Alfonso Fraile (one of the most important New –Figuratives), which consisted, in our opinion, in the search for resources to materialise the representation of a space based on the reflection of one’s own existence, which crystallises in an extremely subjective figuration. Towards 1986, his work gives rise to the experiential space concept, based on the idea that space only exists in as much as man, who is spatial in nature, spreads it around him, thus creating his own background

El agua, el cloro y los seres vivos

El agua, el cloro y los seres vivos

Saturday night purpura: An uncommon presentation of exercise-induced vasculitis

Exercise-induced vasculitis (EIV) is a benign cutaneous vasculitis that affects healthy individuals. We report a case of EIV in a 15-year-old male patient with a striking clinical appearance triggered by a combination of prolonged standing and disco dancing in a warm environment. Pediatric dermatologists should be aware of this activity as a possible trigger of EIV, especially in teenagers

Integración del alumnado de NEE a las aulas ordinarias mediante la educación física.

La inclusión de alumnado del aula enclave al aula ordinaria, es un problema al que se enfrentan actualmente muchos centros escolares y que muchas veces se plantean de manera muy esporádica y por lo tanto no se logran los objetivos que se establecen. Es por ello, por lo que hemos querido dar una visión nueva de una actuación de integración a través de la educación física, mediante el uso de rutinas con pictogramas, trabajo de emociones, esquema corporal, etc. Por lo general, las características del alumnado de las aulas sobre las que queremos trabajar tienen un alto índice de sedentarismo a corto y largo plazo, y por lo tanto pretendemos y creemos necesario comenzar desde la escuela a concienciar de los beneficios que la actividad física les puede dar, permitiéndoles así ampliar sus conocimientos corporales y de disfrute.The special need`s classroom student’s might be included to other classroom, that is a real problem that schools must deal with so that many times they do not know how to approach it. That is why, we have given a new way to tackle it from the physical education area, with different resources, such us pictograms, emotions activities, knowledge of their bodies, etc. In general, the students from those classrooms suffer from overweight not only when they are child, but also when they grow up, therefore we are trying to raise awareness of the physical activity’s wellness till school, giving them the possibility to enjoying it

Flow invariants in the classification of Leavitt path algebras

We analyze in the context of Leavitt path algebras some graph operations introduced in the context of symbolic dynamics by Williams, Parry and Sullivan, and Franks. We show that these operations induce Morita equivalence of the corresponding Leavitt path algebras. As a consequence we obtain our two main results: the first gives sufficient conditions for which the Leavitt path algebras in a certain class are Morita equivalent, while the second gives sufficient conditions which yield isomorphisms. We discuss a possible approach to establishing whether or not these conditions are also in fact necessary. In the final section we present many additional operations on graphs which preserve Morita equivalence (resp. isomorphism) of the corresponding Leavitt path algebra