154 research outputs found

    UHMWPE/SBA-15 nanocomposites synthesized by in situ polymerization

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    Different nanocomposites have been attained by in situ polymerization based on ultra-high molecular weight polyethylene (UHMWPE) and mesoporous SBA-15, this silica being used for immobilization of the FI catalyst bis [N-(3-tert-butylsalicylidene)-2,3,4,5,6-pentafluoroanilinato] titanium (IV) dichloride and as filler as well. Two distinct approaches have been selected for supporting the FI catalyst on the SBA-15 prior polymerization. A study on polymerization activity of this catalyst has been performed under homogenous conditions and upon heterogenization. A study of the effect of presence of mesoporous particles and of the immobilization method is also carried out. Moreover, the thermal characterization, phase transitions and mechanical response of some pristine UHMWPEs and UHMWPE/SBA-15 materials have been carried out. Relationships with variations on molar mass, impregnation method of catalyst and final SBA-15 content have been established

    Mentalidad inquisitorial y jesuitas: el enfrentamiento entre el Cardenal Silíceo y la Compañía de Jesús.

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    The Influence Of Atmospherics In Consumer Research Data Collection

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    This study investigates the effects of ambient atmosphere on market research survey response quality, following approaches in the retail atmospherics literature.  Participants completed a survey task and reported their affect states in a between subjects factorial experiment which manipulated ambient music, lighting and aroma conditions. Structural equation methods were used to test for effects of atmospheric factors on response quality and respondent affect. Findings suggest that ambient atmosphere may contribute to cognitive enrichment up to a point where it becomes distracting. At that point, ambient cues appear to interfere with cognitive processing. Survey response quality may be compromised through reduced positive affect, increased fatigue, or boredom, but the influence mechanism is different between males and females. The importance of stimulus manipulations is stressed and the effects of specific stimulus are provided to help researchers understand the impact toward response quality. Marketing researchers from both the academic and managerial community may be able to improve survey response quality by managing environmental conditions to enhance survey experience

    Los Elementos Floristicos de la Formacion Siripaca (Grupo Ambo, Bolivia) y su Contexto Bioestratigrafico

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    The fossil flora of the Siripaca Formation (Ambo Group, Copacabana Peninsula, Bolivia) was originally characterized by two endemic taxa: Nothorhacopteris kellaybelenensis and Triphyllopteris boliviana. Other taxa of this flora were recently collected and are described here: Paulophyton sommeri, Diplothmema bodenbenderi and Sphenopteridium intermedium. The biostratigraphic value of all the fossil plants described for the Siripaca Formation is here analysed considering these new elements and their presence in other Gondwana floras. We propose a late Visean to earliest Serpukhovian (latest Early Carboniferous) age for the flora in the Siripaca Formation. The biochrons of these elements within South America are also proposed.      

    Polymorphic organization of constitutive heterochromatin in Equus asinus (2n = 62) chromosome 1

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    In the karyotype of Equus asinus (domestic donkey, 2n = 62), non-centromeric heterochromatic bands have been described in subcentromeric and telomeric positions. In particular, chromosome 1 is characterised by heterochromatic bands in the proximal region of the long arm and in the short arm; it has been shown that these regions are polymorphic in size. Here we investigated the variation in the intensity and distribution of fluorescence signals observed on donkey chromosome 1 after in situ hybridization with two DNA probes containing fragments from the two major equine satellite DNA families. Our results show that, in Equus asinus chromosome 1, the amount and distribution of large clusters of satellite DNA can define at least nine polymorphic variants of the constitutive heterochromatin that cannot be detected by C-banding alone

    A theoretical model for the development of a diagnosis-based clinical decision rule for the management of patients with spinal pain

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    The provocative lumbar facet joint

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    Low back pain is the most common pain symptom experienced by American adults and is the second most common reason for primary care physician visits. There are many structures in the lumbar spine that can serve as pain generators and often the etiology of low back pain is multifactorial. However, the facet joint has been increasingly recognized as an important cause of low back pain. Facet joint pain can be diagnosed with local anesthetic blocks of the medial branches or of the facet joints themselves. Subsequent radiofrequency lesioning of the medial branches can provide more long-term pain relief. Despite some of the pitfalls associated with facet joint blocks, they have been shown to be valid, safe, and reliable as a diagnostic tool. Medial branch denervation has shown some promise for the sustained control of lumbar facet joint-mediated pain, but at this time, there is insufficient evidence that it is a wholly efficacious treatment option. Developing a universal algorithm for evaluating facet joint-mediated pain and standard procedural techniques may facilitate the performance of larger outcome studies. This review article provides an overview of the anatomy, pathophysiology, diagnosis, and treatment of facet joint-mediated pain
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