Ultraviolet radiation and aerosol monitoring at Lampedusa, Italy

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

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

Horizontal and vertical structure of the Eyjafjallajökull ash cloud over the UK: a comparison of airborne lidar observations and simulations

During April and May 2010 the ash cloud from the eruption of the Icelandic volcano Eyjafjallajökull caused widespread disruption to aviation over northern Europe. The location and impact of the eruption led to a wealth of observations of the ash cloud were being obtained which can be used to assess modelling of the long range transport of ash in the troposphere. The UK FAAM (Facility for Airborne Atmospheric Measurements) BAe-146-301 research aircraft overflew the ash cloud on a number of days during May. The aircraft carries a downward looking lidar which detected the ash layer through the backscatter of the laser light. In this study ash concentrations derived from the lidar are compared with simulations of the ash cloud made with NAME (Numerical Atmospheric-dispersion Modelling Environment), a general purpose atmospheric transport and dispersion model. The simulated ash clouds are compared to the lidar data to determine how well NAME simulates the horizontal and vertical structure of the ash clouds. Comparison between the ash concentrations derived from the lidar and those from NAME is used to define the fraction of ash emitted in the eruption that is transported over long distances compared to the total emission of tephra. In making these comparisons possible position errors in the simulated ash clouds are identified and accounted for. The ash layers seen by the lidar considered in this study were thin, with typical depths of 550–750 m. The vertical structure of the ash cloud simulated by NAME was generally consistent with the observed ash layers, although the layers in the simulated ash clouds that are identified with observed ash layers are about twice the depth of the observed layers. The structure of the simulated ash clouds were sensitive to the profile of ash emissions that was assumed. In terms of horizontal and vertical structure the best results were obtained by assuming that the emission occurred at the top of the eruption plume, consistent with the observed structure of eruption plumes. However, early in the period when the intensity of the eruption was low, assuming that the emission of ash was uniform with height gives better guidance on the horizontal and vertical structure of the ash cloud. Comparison of the lidar concentrations with those from NAME show that 2–5% of the total mass erupted by the volcano remained in the ash cloud over the United Kingdom

Volcanic ash layer depth: processes and mechanisms

The long duration of the 2010 Eyjafjallajökull eruption provided a unique opportunity to measure a widely dispersed volcanic ash cloud. Layers of volcanic ash were observed by the European Aerosol Research Lidar Network with a mean depth of 1.2 km and standard deviation of 0.9 km. In this paper we evaluate the ability of the Met Office's Numerical Atmospheric-dispersion Modelling Environment (NAME) to simulate the observed ash layers and examine the processes controlling their depth. NAME simulates distal ash layer depths exceptionally well with a mean depth of 1.2 km and standard deviation of 0.7 km. The dominant process determining the depth of ash layers over Europe is the balance between the vertical wind shear (which acts to reduce the depth of the ash layers) and vertical turbulent mixing (which acts to deepen the layers). Interestingly, differential sedimentation of ash particles and the volcano vertical emission profile play relatively minor roles

Unexpected vertical structure of the Saharan Air Layer and giant dust particles during AER-D

The Saharan Air Layer (SAL) in the summertime eastern Atlantic is typically well mixed and 3-4 km deep, overlying the marine boundary layer (MBL). In this paper, we show experimental evidence that at times a very different structure can be observed. During the AERosol properties - Dust (AER-D) airborne campaign in August 2015, the typical structure described above was observed most of the time, and was associated with a moderate dust content yielding an aerosol optical depth (AOD) of 0.3-0.4 at 355 nm. In an intense event, however, an unprecedented vertical structure was observed close to the eastern boundary of the basin, displaying an uneven vertical distribution and a very large AOD (1.5-2), with most of the dust in a much lower level than usual (0.3-2 km). Estimated dust concentrations and column loadings for all flights during the campaign spanned 300-5500 and 0.8-7.5 g m−2, respectively. The shortwave direct radiative impact of the intense dust event has been evaluated to be as large as −260±30 and −120±15 W m−2 at the surface and top of atmosphere (TOA), respectively. We also report the correlation of this event with anomalous lightning activity in the Canary Islands. In all cases, our measurements detected a broad distribution of aerosol sizes, ranging from ∼0.1 to ∼80 µm (diameter), thus highlighting the presence of giant particles. Giant dust particles were also found in the MBL. We note that most aerosol models may miss the giant particles due to the fact that they use size bins up to 10-25 µm. The unusual vertical structure and the giant particles may have implications for dust transport over the Atlantic during intense events and may affect the estimate of dust deposited to the ocean. We believe that future campaigns could focus more on events with high aerosol load and that instrumentation capable of detecting giant particles will be key to dust observations in this part of the world

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

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

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.

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