582 research outputs found

    Ultraviolet radiation and aerosol monitoring at Lampedusa, Italy

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    The measurements of UV spectral irradiance, ozone and aerosol load obtained with a double monochromator Brewer at the Station for Climate Observations of the National Agency for New Technology, Energy and Environment (ENEA) in Lampedusa, Italy, are presented. To derive the aerosol optical depth, the direct-sun measurements at the Brewer operational wavelengths (302.1, 306.3, 310.1, 313.5, 316.8 and 320.1 nm) were calibrated using the Langley method. A radiative transfer model was used to investigate the role of ozone and aerosols in modulating UV irradiance and to reproduce the measured UV spectra. The optical scattering and absorption properties of aerosols input to the model have been derived from measured size-distributions. The modelled and measured UV spectra are in agreement for different atmospheric conditions and allowed us to estimate the radiative impact of the aerosols for two case studies related to the PAUR II campaign held in 1999

    Lidar observations of the Planetary Boundary Layer above the city of Thessaloniki, Greece

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    Aerosol measurements have been performed in Greece since 1994, using a backscattering lidar system. The main scientific objective has been to evaluate the vertical structure of the Planetary Boundary Layer (PBL) in urban sites of Greece, using suspended aerosols as tracers of the atmospheric motion. The observations presented here were performed in early 1996, over the city of Thessaloniki in Northern Greece, close to the sea shore. The lidar system was operated under varying air pollution and meteorological conditions. The vertical profiles of the aerosol extinction and backscattering coefficients were retrieved from the lidar signal, using the Fernald-Klett inversion algorithm. Comparison between standard meteorological data from radiosondes and ground stations proves that lidar aerosol profiles can be successfully used to monitor the time variation in the layering of the lower troposphere

    Avaliação do Programa Reciclando Ando em instituições educacionais e comunidades vulneráveis de Montería-Colombia, na Responsabilidade Social Universitária. Estudo de caso /

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    El objetivo del artículo3 es establecer la incidencia de Reciclando Ando como iniciativa de proyección social liderada por el programa de Comunicación Social-Periodismo de la Universidad Pontificia Bolivariana Montería -UPB-, mediante una investigación evaluativa de corte cualitativo y un diseño de campo, no experimental-transversal. La muestra estuvo constituida por 19 gestores, 15 beneficiados y 3 actores/organizaciones participantes. El estudio se desarrolló en 3 fases: definición de políticas de proyección social y caracterización de Reciclando Ando, análisis del proceso desde la mirada de los gestores y análisis del proceso desde la apreciación de los beneficiarios

    The Role of Online vs Face-to-Face Learning Environments in Academic Engagement Profiles: A Comparative Study During and Post Lockdown

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    El presente trabajo tuvo como objetivo contrastar perfiles de Engagement en estudiantes universitarios colombianos en dos contextos educativos diferenciales, la educación en línea originada por el confinamiento, y el entorno de aula de manera presencial, con el fin de com-prender posibles diferencias entre los grupos. Para ello se evaluaron 742 estudiantes universi-tario, en dos contextos de enseñanza diferenciales, la educación en línea impuesta durante el confinamiento por COVID-19, y el entorno de aula presencial post confinamiento. La muestra estuvo conformada por estudiantes universitarios colombianos entre 18 y 25 años, de nivel socioeconómico medio y bajo. La aproximación metodológica fue en dos pasos, la primera una comparación pre y post test, la segunda a partir de un análisis de clústeres desde la cual se definieron cuatro perfiles clasificados de acuerdo con las puntuaciones de los y las participantes en la escala UWES–S (Student Academic Engagement Scale). En los resultados, las compara-ciones múltiples señalaron diferencias significativas en los niveles de vigor, absorción y entre los cuatro perfiles de Engagement: alto, medio, en proceso y bajo. Los resultados evidenciaron que el grupo de estudiantes con alto nivel estuvo integrado tanto por estudiantes en modalidad virtual como presencial. No obstante, los grupos compuestos por estudiantes con perfiles de bajos puntajes se conformaron por más estudiantes en la modalidad de estudios en línea, señalando un patrón donde la escolaridad virtual impuesta durante el confinamiento se asoció con menor motivación para aprender. En los análisis por sexo, las mujeres presentaron mayores niveles que los hombres en ambos contextos de enseñanza.The objective of this study was to contrast engagement profiles in Colombian university students in two distinct educational contexts, the online education promoted by the lockdown and the face-to-face classroom environment, in order to understand possible differences between the groups. For this purpose, 742 university students were evaluated in two educational contexts: the online education during the COVID-19 lockdown and the subsequent face-to-face classroom environment. The sample consisted of Colombian university students between 18 and 25 years old, of middle and low socioeconomic level. As to the methodological approach, a pre- and post-test comparison was done first, followed by a cluster analysis which allowed to define four profiles based on participants’ scores on the UWES-S scale (Student Academic Engagement Scale). Multiple comparisons showed significant differences in the levels of vigor, absorption, and among the four engagement profiles: high, medium, in process, and low. The results showed that the group of students with higher scores was composed of participants in both virtual and face-to-face modalities. However, the groups with lower scores were made up of students in the online modality mainly, indicating a pattern where virtual schooling imposed during lockdown was associated with lower motivation for learning. In the analyses by gender, females presented higher levels than males in both teaching contexts

    Management of risk of breast carcinoma in postmenopausal women.

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    Breast carcinoma is the most frequent tumor in the female population. Many factors can influence the risk of breast cancer; some of them, such as old age and breast cancer 1/2 (BRCA1/BRCA2) gene mutations, are associated with a fourfold increase in risk. A previous diagnosis of atypical ductal or lobular hyperplasia or having a first-degree relative with a carcinoma are factors associated with a two- to fourfold increase in risk. A relative risk between 1 and 2 is associated with longer exposure to endogenous hormones as a result of early menarche, late menopause and obesity, or with recent and prolonged use of hormone replacement therapy (HRT) or with behavioural factors such as high alcohol and fat intake. Is it possible to modify breast cancer risk in postmenopausal women? Risk factors related to lifestyle can be changed, even if it is not clear whether modifying these behavioural factors during the postmenopausal period will influence the overall breast cancer risk. For instance, the influence of exogenous hormones throughout life (both oral contraceptives and HRT) should be evaluated according to the individual risk-benefit ratio. The problem is even more complex for women who carry genetic mutations and for those who have close relatives with breast cancer, who may be candidates for risk reduction strategies. Prophylactic bilateral mastectomy is still controversial, but is frequently offered to or requested by this group of women and may be indicated in BRCA1/BRCA2 carriers. Chemoprevention with tamoxifen and with the new selective estrogen receptor modulators, namely raloxifene, is very promising and deserves a thorough discussion for all high-risk women
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