3,714 research outputs found

    Jet shapes in ep collisions at HERA

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    New measurements of the jet shape in ep collisions at HERA using the k_T-cluster jet algorithm are presented.Comment: 7 pages, 3 figures; plenary talk given at the 3rd UK Phenomenology Workshop on HERA Physics, Durham, UK, September 199

    Seedling vigor variation among 80 recombinant chromosome substitution lines (RCSL) of barley (Hordeum vulgare)

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    del Pozo, A (del Pozo, Alejandro). Univ Talca, Fac Ciencias Agr, Talca, Chile.Seedling vigor of 80 recombinant chromosome substitution lines (RCSL) of barley (Hordeum vulgare). Cien. Inv. Agr. 38 (1): 137-147. The seedling vigor of 80 barley recombinant chromosome substitution lines (RCSLs) was measured for selecting high seedling vigor genotypes. The RCSLs were derived from a cross between H. vulgare subsp. spontaneum and H. vulgare subsp. vulgare 'Harrington'. The work was carried out under greenhouse conditions during the summer of 2008. The experimental design was an alpha lattice with 3 replicates. In each replicate, 40 plants were established, distributed in eight polyethylene pots containing sand as substrate, which were fertilized an irrigated. The emergence of seedlings, number of leaves and shoots, dry matter of leaves, shoots and roots and leaf area of fully expanded leaves were measured. In addition, growth indices were calculated: emergence rate, leaf appearance rate, relative leaf expansion rate, relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and the allometric coefficient (K) between root and shoot thy matter. All calculated indices varied significantly among genotypes (P <= 0.05) and some RCSLs showed better early vigor associated traits than 'Harrington'. The dry matter accumulation 30 DAS (when the experiment ended) was significant and positively correlated with the RGR (r=0.61; P <= 0.05) and NAR (r=0.41; P <= 0.05). The K coefficient was negatively correlated with NAR (r=-0.40, P <= 0.05). The genotypes with the greatest seminal vigor were the RCSLs 45, 92, 112 and 'Harrington', whereas the RCSLs 5, 19,47 and 121 presented the lowest seminal vigor

    QCD

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    We discuss QCD studies that will be possible at LEP2. We examine both experimental and theoretical aspects of jets, fragmentation functions, multiplicities and particle spectra.Comment: 44 pages, Latex, epsfig, 18 figures, to appear on the Report of the Workshop on Physics at LEP2, CERN 96-01, vol. 1, 199

    Preparation of the catalyst support from the oil-shale processing by-product

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    5-methylresorcinol and the technical mixture of oil-shale phenolic compounds were applied for carbon aerogel preparation. Gels, which were prepared via base catalyzed polymerization were dried under supercritical conditions and subsequent pyrolysis of obtained dry aerogels led to carbon aerogels. Activation of carbon aerogel with CO2 and H2O was performed and porosity and the specific surface area of activated carbon aerogels were studied. Langmuir specific surface areas of well over 2000 m2/g were achieved and microporosity of carbon aerogel samples was tuneable ranging from below 50% until over 85%. Impregnation with the complex [Pd(C4HF6O)2] was carried out in supercritical CO2 using H2 for a quick reduction of Pd(II) to Pd(0). Eventually, highly porous material decorated with nanoparticles of black palladium was obtained having a homogeneous metal distribution

    Respuestas en desarrollo del ajo a la temperatura y el fotoper\uedodo

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    Bulb initiation and maturity of four Chilean clones of garlic ( Allium sativum L.) were studied in controlled and field conditions in order to assess temperature and photoperiod requirements of selected clones. The effect of cold storage temperature prior to planting and photoperiod on bulb initiation was assessed in two clones of garlic. In one experiment bulbs were stored at 4, 7, 10, 13 and 16\ub0C for 20, 40 or 60 days, and planted in pots in a heated greenhouse with a 14 h photoperiod. In a second experiment bulbs of the same clones were stored at 4 and 10\ub0C, and room temperature (&gt;13\ub0C) for 30 days, and later grown in a heated greenhouse with 8, 10, 12, 14 or 16 h of photoperiod. In the field, days from emergence to bulb initiation and to maturity were evaluated in 13 clones planted on six sequential planting dates. Percentage of bulbing increased and the number of days from emergence to bulb initiation decreased, as storage temperature decreased and duration of storage increased. Plants of studied clones did not form bulbs with photoperiods of 8, 10 or 12 h with any storage temperature. All plants of both clones formed bulbs when photoperiod was over 14 h and storage temperature was 4 or 7\ub0C. A reduction on the period emergence-bulb initiation was observed as planting date was delayed from April to September.Se estudi\uf3 la bulbificaci\uf3n y maduraci\uf3n de clones de ajo ( Allium sativum L.) chilenos bajo condiciones controladas y de campo a fin de determinar los requerimientos de temperatura y fotoper\uedodo de los clones seleccionados. Se estim\uf3 el efecto del almacenaje en fr\uedo previo a la plantaci\uf3n y del fotoper\uedodo en la bulbificaci\uf3n de dos clones de ajo. En un experimento se almacenaron bulbos a 4, 7, 10, 13 y 16\ub0C por 20, 40 \uf3 60 d\uedas, y se plantaron en macetas en invernadero calefaccionado, con 14 h de fotoper\uedodo. En un segundo experimento se almacenaron bulbos de los mismos clones a 4 y 10\ub0C y temperatura ambiente (&gt;13\ub0C) durante 30 d\uedas, y luego se hicieron crecer en invernadero calefaccionado con fotoper\uedodos de 8, 10, 12, 14 \uf3 16 h. En el campo, se evaluaron los d\uedas desde emergencia a inicio de bulbificaci\uf3n y a madurez en 13 clones plantados en seis fechas consecutivas. El porcentaje de bulbificaci\uf3n aument\uf3 y el n\ufamero de d\uedas desde emergencia a bulbificaci\uf3n disminuy\uf3 a medida que la temperatura de almacenaje disminuy\uf3 y el tiempo de almacenaje aument\uf3. Las plantas de los clones estudiados no formaron bulbos con fotoper\uedodos de 8, 10 \uf3 12 h, con cualquier temperatura de almacenaje. Todas las plantas de ambos clones formaron bulbos cuando el fotoper\uedodo estuvo sobre 14 h y la temperatura de almacenaje fue 4 \uf3 7\ub0C. Se observ\uf3 una reducci\uf3n en el per\uedodo emergencia - inicio de bulbificaci\uf3n, a medida que la fecha de plantaci\uf3n se atras\uf3 desde abril a septiembre

    Fracture energy of coarse recycled aggregate concrete using the wedge splitting test method: influence of water-reducing admixtures

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    The aim of this study is to evaluate the effect of the replacement levels of coarse natural aggregates with recycled aggregates and water-reducing admixtures on the fracture energy of concrete. Four mixes with 0, 20, 50 and 100% replacement ratios are produced per concrete family: without admixture, with plasticizer and with superplasticizer. The experimental fracture energy is tested using the wedge splitting test method on notched specimens at 28 days. The results prove that the incorporation of up to 20% coarse recycled aggregates led to improved energy absorption capacity of concrete mixes with water-reducing admixtures, reaching 1.5% for concrete with normal plasticizer and 7.0% for concrete with superplasticizer. Furthermore, the compressive strength, slump, and fresh density are tested in order to evaluate the effect of water-reducing admixtures on recycled aggregate concrete with different ratios of coarse natural aggregate replacement, allowing to conclude that the use of plasticizers and superplasticizers improves the behaviour of recycled aggregate concrete for all these properties

    Oil shale phenol-derived aerogels as supports for palladium nanoparticles

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    Palladium hexafluoroacetylacetonate [Pd(C4HF6O)2], which is both soluble and easily reducible in supercritical carbon dioxide, was used to impregnate the porous structure of carbon aerogels based on phenolic compounds from oil shale processing water. Metallic nanoparticles uniformly distributed on the surface of the carbon matrix enable it to be used as a catalyst. Through the study of various pyrolysis programs and physical activation with CO2 and H2O in the carbon aerogel preparation process, significant increases in the BET specific surface area of the carbon supports (achieving values of over 1600 m2/g) were achieved, and the possibility of tailoring the porosity of the samples (microporosity ranging from 40% up to over 90%) was realized

    Evolution of occupational asthma: Does cessation of exposure really improve prognosis?

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    SummaryAimTo assess the evolution of occupational asthma (OA) depending on whether the patient avoids or continues with exposure to the offending agent.MethodsStudy in patients diagnosed with OA using a specific inhalation challenge. Patients underwent the following examinations on the same day: clinical interview, physical examination, forced spirometry, methacholine test and determination of total IgE. Clinical improvement, deterioration or no change were defined according to the changes seen on the GINA severity scale at the time of diagnosis.ResultsOf the 73 patients finally included, 55 had totally ended exposure and 18 continued to be exposed at work. Clinical improvement was observed in 47% of those who had terminated exposure and in 22% of those who remained exposed; clinical deterioration was observed in 14% and 17% respectively (p = 0.805). Logistical regression analysis, including the type of agent and the persistence or avoidance of exposure among the variables, did not show any predictive factors of clinical evolution. Similarly, the changes in FEV1 and in bronchial hyperresponsiveness were not associated with the avoidance or continuation of exposure to the causative agent.ConclusionsAvoiding exposure to the causative agent in patients with OA does not seem to improve prognosis in this disease. Despite these findings, there is insufficient evidence to recommend a change in current management guidelines

    Frailty is associated with objectively assessed sedentary behaviour patterns in older adults: Evidence from the Toledo Study for Healthy Aging (TSHA)

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    Objective: The aim of this study was to examine the association of sedentary behaviour patterns with frailty in older people. Setting: Clinical setting. Design: Cross-sectional, observational study. Participants and measurements: A triaxial accelerometer was used in a subsample from the Toledo Study for Healthy Aging (519 participants, 67–97 years) to assess several sedentary behaviour patterns including sedentary time per day, the number and duration (min) of breaks in sedentary time per day, and the proportion of the day spent in sedentary bouts of 10 minutes or more. Frailty was assessed using the Frailty Trait Scale (FTS). Regression analysis was used to ascertain the associations between sedentary behaviour patterns and frailty. Results: Sedentary time per day and the proportion of the day spent in sedentary bouts of 10 minutes or more, were positively associated with frailty in the study sample. Conversely, the time spent in breaks in sedentary time was negatively associated with frailty. Conclusion: In summary, breaking up sedentary time and time spent in sedentary behaviour are associated with frailty in older people

    The pharmaceutical compounding: acquisition of competences by PBL and out of class strategie

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    La formulación magistral, una de las actividades profesionales más representativas del farmacéutico, consiste en la elaboración, de acuerdo con una prescripción médica, de un medicamento personalizado, adaptado a un paciente concreto, en un compromiso profesional de solucionar un problema de salud específico. La amplia oferta de medicamentos industriales ha reducido considerablemente esta actividad, que a pesar de todo, debe considerarse una herramienta de futuro en sintonía con la tendencia personalizadora actual de la medicina y las necesidades del paciente. Los conocimientos y competencias requeridas para dicha actividad profesional se introducen actualmente en la carrera de Farmacia mediante una asignatura optativa. En el presente trabajo se presenta el planteamiento metodológico diseñado por el Grupo de Innovación Docente de Tecnología Farmacéutica (GIDTF) y el grupo e-Galenica, ambos de la Universidad de Barcelona, para esta asignatura. Dicha metodología esta basada en el Aprendizaje Basado en Problemas (ABP) incluyendo tutorías y prácticas de campo, apoyada en estrategias no presenciales como foro de debate, recursos on-line, cuestionarios y tareas de autoevaluación a través de la plataforma Moodle del Campus Virtual de la UB. Se evalúan asimismo los resultados académicos y las respuestas de los estudiantes a las encuestas realizadas en relación al sistema de impartición de la asignatura.The pharmaceutical compounding, one of the most representative professional activities of pharmacists, involves the preparation of an individualized medicine tailored to a specific patient in a professional commitment to solve a specific health problem, according to a prescription. The wide range of industrial medicine has significantly reduced this activity, which nevertheless should be considered a tool of the future in line with the current trend of personalizing medicine and patient needs. The knowledge and competences required for this professional activity are introduced to the students of Pharmacy through an optional subject. In this paper we present the methodological approach developed for this subject by the Teaching Innovation Group of Pharmaceutical Technology (GIDTF) and e-Galenica group, both from the University of Barcelona. This methodology is based on Problem-Based Learning (PBL) including tutorials and practices in other centres, supported by out of class strategies as discussion forum, online resources, self-assessment questionnaires and work through the platform Moodle of Virtual Campus UB. The academic performance and student responses to surveys in relation to the didactic methodology are also assessed
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