223 research outputs found

    L'Osservatorio Geofisico di Lipari ed i 40 anni della Rete Sismica Permanente del Tirreno Meridionale

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    In 1966, the Istituto Internazionale di Vulcanologia (I.I.V.), gave the go ahead to the ambitious project of setting up a seismic network in the southern Tyrrhenian Sea, an area of extraordinary geophysical interest, which until then was not covered by seismic monitoring. At the time, there were single seismic stations on the rest of the italian peninsula. These were inside universities, public and private bodies and at the numerous observatories of the Istituto Nazionale di Geofisica (founded in 1936 by Antonino Lo Surdo and becoming independent of the Consiglio Nazionale delle Ricerche (C.N.R,. in 1945) and still used mechanical seismographs, with masses weighing from 80 up to 1300 Kg. On the Aeolian Islands instead, electromagnetic seismometers were employed from the start. The experimental network, planned in the Willmore laboratories at Edinburgh and tested in the Aeolian Islands over a two-year period, represented the starting point for the Permanent Seismic Network (PSN) of the Southern Tyrrhenian. After the experience of the Laboratorio Internazionale per le Ricerche Vulcanologiche (L.I.R.V. - C.N.R.), of the Istituto di Vulcanologia of the University of Catania, the independent I.I.V. - C.N.R., together with the observatory, was launched in 1969. In the course of the seventies, every island of the Aeolian archipelago, was equipped with at least a seismic station and the 3 sensor systems (triaxial systems) began to become widely used. In the eighties, the “Sismologia Eolie” project was started, aimed at a further develop and update the seismic net. With the wide use of magnetic tape recording, the instrumental data stored could be more readily transported on suitable drums to the main centre in Catania for analysis. Here, Research Units were established in order to prepare the way for enhanced interaction between technical staff and research groups. The instrumental geophysical investigations, progressively extended and in a permanente form to Eastern Sicily and particular around Etna. From the nineties, operations room in Catania was fully active, working 24/24, and ensuring the seismic and volcanic surveillance of Etna, Stromboli and Vulcano. The Geophysical Observatory of Lipari and the main centre of the Institute in Catania, were merged in 2001 into the new Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the network of the Aeolian Islands became an integral part of the Permanent Seismic Network (PSN) of Eastern Sicily and Southern Calabria. Special prominence will be given in the course of this historical reconstruction to the evolution of instrumental seismology, thanks to forty years of continuous input, indispensable for the understanding of the seismogenetic processes in the area, this still represents the chief undertaking of the geophysical observatory on Lipari, whose important scientific but also social role must be acknowledged in the growing interaction between research and civil protection

    Duodenal Leiomyosarcoma Mimicking a Pancreatic Pseudocyst

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    A case of duodenal leiomyosarcoma presenting as a cystic mass is reported. Amylase, tumour markers levels in the cyst fluid and radiological findings suggested an inflammatory pancreatic pseudocyst. Exploratory laparotomy and frozen section examination showed a smooth muscle tumour of the duodenum. Pancreatoduodenectomy with pylorus-preser vation was performed and the patient remained symptom-free at 8 months follow-up

    Large-scale lateral saturated soil hydraulic conductivity as a metric for the connectivity of subsurface flow paths at hillslope scale

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    Lateral saturated soil hydraulic conductivity, Ks,l, is the soil property governing subsurface water transfer in hillslopes, and the key parameter in many numerical models simulating hydrological processes at the hillslope and catchment scales. Likewise, the hydrological connectivity of the lateral flow paths plays a significant role in determining the rate of the subsurface flow at various spatial scales. This study investigates the relationship between Ks,l and hydrological connectivity at the hillslope spatial scale. Ks,l was determined by the subsurface flow rates intercepted by drains and water table depths observed in a well network. The hydrological connectivity was evaluated by the synchronicity among water table peaks, and between these and the peaks of the drained flow. Rainfall and soil moisture were used to investigate the influence of the transient hydrological soil condition on connectivity and Ks,l. As the synchronicity of the water table response between wells increased, the lag times between the peaks of water levels and those of the drained subsurface flow decreased. Moreover, the most synchronic water table rises determined the highest drainage rates. The relationships between Ks,l and water table depths were highly non-linear, with a sharp increase in the values for water table levels close to the soil surface. Estimated Ks,l values for the full saturated soil were in the order of thousands of mm h−1, suggesting the activation of macropores in the root zone. The Ks,l values determined at the peak of the drainage events were correlated with the indicators of synchronicity. The sum of cumulative rainfall and antecedent soil moisture was correlated with the connectivity indicators and Ks,l. We suggest that, for simulating realistic processes at the hillslope scale, the hydrological connectivity could be implicitly considered in hydrological modelling through an evaluation of Ks,l at the same spatial scale

    Advances in Ecohydrology for Water Resources Optimization in Arid and Semi-Arid Areas

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    Conserving water resources is a current challenge that will become increasingly urgent in future due to climate change. The arid and semi-arid areas of the globe are expected to be particularly affected by changes in water availability. Consequently, advances in ecohydrology sciences, i.e., the interplay between ecological and hydrological processes, are necessary to enhance the understanding of the critical zone, optimize water resources’ usage in arid and semi-arid areas, and mitigate climate change. This Special Issue (SI) collected 10 original contributions on sustainable land management and the optimization of water resources in fragile environments that are at elevated risk due to climate change. In this context, the topics mainly concern transpiration, evapotranspiration, groundwater recharge, deep percolation, and related issues. The collection of manuscripts presented in this SI represents knowledge of ecohydrology. It is expected that ecohydrology will have increasing applications in the future. Therefore, it is realistic to assume that efforts to increase environmental sustainability and socio-economic development, with water as a central theme, will have a greater chance of success

    A remote sensing and modeling integrated approach for constructing continuous time series of daily actual evapotranspiration

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    Satellite remote sensing-based surface energy balance (SEB) techniques have emerged as useful tools for quantifying spatialized actual evapotranspiration at various temporal and spatial scales. However, discontinuous data acquisitions and/or gaps in image acquisition due to cloud cover can limit the applicability of satellite remote sensing (RS) in agriculture water management where continuous time series of daily crop actual evapotranspiration (ETc act) are more valued. The aim of the research is to construct continuous time series of daily ETc act starting from temporal estimates of actual evapotranspiration obtained by SEB modelling (ETa eb) on Landsat-TM images. SEBAL model was integrated with the FAO 56 evaporation model, RS-retrieved vegetative biomass dynamics (by NDVI) and on-field measurements of soil moisture and potential evapotranspiration. The procedure was validated by an eddy covariance tower on a vineyard with partial soil coverage in the south of Sardinia Island, Italy. The integrated modeling approach showed a good reproduction of the time series dynamics of observed ETc act (R2 =0.71, MAE=0.54 mm d-1, RMSE=0.73 mm d-1). A daily and a cumulative monthly temporal analysis showed the importance of integrating parameters that capture changes in the soil-plant-atmosphere (SPA) continuum between Landsat acquisitions. The comparison with daily ETc act obtained by the referenced ET fraction (ETrF) method that considers only weather variability (by ETo) confirmed the lead of the proposed procedure in the spring/early summer periods when vegetation biomass changes and soil water evaporation have a significant weight in the ET process. The applied modelling approach was also robust in constructing the missing ETc act data under scenarios of limited cloud-free Landsat acquisitions. The presented integrated approach has a great potential for the near real time monitoring and scheduling of irrigation practices. Further testing of this approach with diverse dataset and the integration with the soil water modeling is to be analyzed in future work

    Spatio-temporal variation of surface soil hydraulic properties under different tillage and maize-based crop sequences in a Mediterranean area

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    Aims: The surface crust formed by the drop impact of rainfall and/or irrigation is a prevalent characteristic in many Mediterranean soils. However, the temporal variation of soil hydraulic properties induced by surface crust during the high-frequency irrigation has rarely been investigated. Methods: Beerkan infiltration tests in conjunction with the BEST method were used to investigate the effects of surface crusting on the spatio-temporal variation of saturated soil hydraulic conductivity (Ks, mm s−1), sorptivity (S, mm s−0.5), mean pore size (r, mm), number of effective pores per unit area (N, m−2) in Agramunt, NE Spain. Results: In response to autumn tillage, intensive tillage (IT) increased Ks and S due to higher r and N, but both declined after 60 days. Reduced tillage (RT), maintained comparable Ks and S values, despite having a lower N value. After the spring tillage, both IT and RT developed crusted layers, resulting in decreased Ks, S and N. Long-term no-tillage (NT) showed an increasing trend of Ks and S over time, except for the last sampling. Spatial variation (i.e., between the rows, B-row vs. within the row of crops, W-row) of Ks and S was found, and non-crusted soils (W-row) had consistently higher Ks and S than crusted soils (B-row). Conclusions: Conservation tillage i.e., RT and NT improve the surface soil structure and reduce the risk of crust development. Surface cover by crops may help to prevent crust formation within the row of crops, improving soil hydraulic conductivity

    Comparison of anti-transglutaminase ELISAs and an anti-endomysial antibody assay in the diagnosis of celiac disease: A prospective study

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    Background: Most studies of anti-transglutaminase (anti-tTG) assays have considered preselected groups of patients. This study compared the sensitivity, specificity, and predictive value of an immunofluorescence method for anti-endomysial antibodies (EmAs) and two anti-tTG ELISAs, one using guinea pig tTG (gp-tTG) and the other human tTG (h-tTG) as antigen, in consecutive patients investigated for suspected celiac disease (CD). Methods: We studied 207 consecutive patients (99 men, 108 women; age range, 17-84 years) who underwent intestinal biopsy for suspected CD. Patients presented with one or more of the following: weight loss, anemia, chronic diarrhea, abdominal pain, dyspepsia, alternating bowel habits, constipation, pain in the joints, and dermatitis. At entry to the study, an intestinal biopsy was performed and a serum sample was taken for IgA EmAs, anti-gp-tTG, and anti-h-tTG. Results: Intestinal histology showed that 24 patients had partial or total villous atrophy; in these patients the diagnosis of CD was confirmed by follow-up. The remaining 183 patients had villous/crypt ratios that were within our laboratory's reference values and were considered controls. Serum EmAs, anti-gp-tTG, and anti-h-tTG were positive in all 24 CD patients; in the control group, none were positive for serum EmAs, but 15 of 183 (8.2%) were positive for anti-gp-tTG, and 6 of 183 (3.3%) were positive for anti-h-tTG. Sensitivity was 100% for all assays, whereas specificity was 100% for the EmA, 92% for the anti-gp-tTG, and 97% for the anti-h-tTG assay. The negative predictive value was 100% for all assays; the positive predictive value was 100% for the EmA, 80% [95% confidence interval (CI), 65-95%] for the anti-h-tTG (P = 0.03 vs EmA) and 60% (95% CI, 44-76%) for the anti-gp-tTG assay (P = 0.0002 vs EmA). Areas (95% CIs) under the ROC curves were 0.987 (0.97-1.0) for anti-h-tTG and 0.965 (0.94-0.99) for anti-gp-tTG. Most of the patients testing false positive for anti-tTG had Crohn disease or chronic liver disease. Conclusions: Although both anti-tTG ELISAs showed optimum sensitivity, their lack of specificity yielded positive predictive values significantly lower than those for the EmA assay. © 2002 American Association for Clinical Chemistry

    La agricultura ecológica a largo plazo en plantaciones de cítricos permite la recuperación del carbono orgánico del suelo

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    [ES] Se ha demostrado que el manejo del suelo bajo agricultura ecológica puede aumentar el contenido de carbono orgánico en el suelo moderando el incremento de los gases de efecto invernadero, pero hasta la fecha las evaluaciones cuantitativas basadas en mediciones a largo plazo han sido escasas, especialmente bajo condiciones mediterráneas. En esta investigación se examinaron los cambios en el contenido de carbono orgánico como respuesta a la agricultura ecológica con cobertura vegetal en una plantación de cítricos en el área mediterránea, utilizando una base de datos de 21 años. El incremento de contenido de carbono orgánico en el suelo fue más evidente tras cinco años desde el cambio del manejo del suelo, sugiriendo que, para plantaciones de cítricos en ambientes mediterráneos, los estudios deberían tener una duración superior a cinco años. La sata de secuestro de carbono orgánico no cambió significativamente durante los 21 años de observaciones, con valores que oscilaron entre -1.10 Mg C ha-1 a-1 y 1.89 Mg C ha-1 a-1. Tras 21 años, un total de 61 t CO2 ha-1 fueron secuestradas en las áreas de acumulación de carbono en el suelo. Estos resultados demuestran que la agricultura ecológica es una estrategia efectiva para restaurar o incrementar los niveles de carbono orgánico en el suelo en los sistemas de cítricos mediterráneos.[EN] It has been shown that soil management under organic farming can enhance soil organic carbon, thereby mitigating atmospheric greenhouse gas increases, but until now quantitative evaluations based on long term experiments are scarce, especially under Mediterranean conditions. Changes in soil organic carbon (SOC) content were examined in response to organic management with cover crops in a Mediterranean citrus plantation using 21 years of survey data. Soil organic carbon increase was more apparent 5 years after a land management change suggesting that, for citrus plantations on Mediterranean conditions, studies should be longer than five years in duration. Soil organic carbon sequestration rate did not significantly change during the 21 years of observation, with values ranging from -1.10 Mg C ha(-1) y(-1) to 1.89 Mg C ha(-1) y(-1). After 21 years, 61 Mg CO2 ha(-1) were sequestered in long-lived soil C pools. These findings demonstrate that organic management is an effective strategy to restore or increase SOC content in Mediterranean citrus systems.This research was funded by the European Union Seventh Framework Program (FP7/2007-2013) under grant no. 603498 (RECARE Project) and the research projects GL2008-02879/BTE and LEDDRA 243857.Novara, A.; Pulido, M.; Rodrigo-Comino, J.; Di Prima, S.; Smith, P.; Gristina, L.; Giménez Morera, A.... (2019). Long-term organic farming on a citrus plantation results in soil organic carbon recovery. Cuadernos de Investigación Geográfica. 45(1):271-286. https://doi.org/10.18172/cig.3794S27128645
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