Use of neural networks for tropospheric ozone time series approximation and forecasting ? a review

International audienceThe use of artificial neural networks in atmospheric science expands constantly. During the last years, many papers were published dealing with air pollution modeling. A number of papers deals with the time series approximation and forecasting of tropospheric ozone concentration. Neural networks have been found to outperform other statistical techniques like multiple regression etc. This paper reviews and discusses some practical aspects of the proposed neural network models applied to ozone concentration approximation and forecasting

Performance comparison of heating control strategies combining simulation and experimental results

Different heating system controllers for passive solar buildings are compared on two different buildings.The performance criterion combines energy performance and thermal comfort using the "costfunction" paradigm. The experimental facilities did not allow a direct experimental comparison by using two identical buildings. The controllers were implemented alternatively in one building and a performance comparison was obtained in two ways: first by identifying short periods that have similar driving variables (weather conditions and building occupancy) and comparing the experimental results obtained in both cases. The second method mixes experiments and simulation using a well-tuned model of the building and its occupants. This paper discusses the results obtained using the above methods and shows that both methods give consistent estimates of the difference between controllers, while the second method allows to extrapolate useful information from the limited data available

HOMOGENIZATION OF THE HELLENIC CLOUD COVER TIME SERIES - PRELIMINARY RESULTS

Cloud cover is an important meteorological parameter because it affects the ra- diative energy balance of the Earth and precipitation and plays a major role in the hydrological cycle. Impact of clouds on the radiative balance is twofold: cloud cover modifies the albedo of the Earth and the atmospheric long wave radiative exchange. Long records of cloud cover data are the result of human estimations made during the synoptic observation hours at each meteorological station. Currently the quantification of cloud cover has been automated due to the advent of modern remote sensing space (e.g. satellites) and ground sky monitoring techniques (e.g. sky cameras). All weather time series records may suffer from inhomogeneities; their use in climatology requires homogenization. In this work we attempt a preliminary homogenization of the cloud cover time series of the Hellenic National Weather Service (HNMS) network. Data come from 36 meteorological stations, and cover the period from 1975 to 2004. Raw data comprise (synoptic) hourly cloud cover observations which we subjected to quality control before producing daily and then monthly average cloud cover time series. For this homogenization exercise we used the HOMER software tool

HOMOGENIZATION OF THE HELLENIC CLOUD COVER TIME SERIES - PRELIMINARY RESULTS

Cloud cover is an important meteorological parameter because it affects the ra- diative energy balance of the Earth and precipitation and plays a major role in the hydrological cycle. Impact of clouds on the radiative balance is twofold: cloud cover modifies the albedo of the Earth and the atmospheric long wave radiative exchange. Long records of cloud cover data are the result of human estimations made during the synoptic observation hours at each meteorological station. Currently the quantification of cloud cover has been automated due to the advent of modern remote sensing space (e.g. satellites) and ground sky monitoring techniques (e.g. sky cameras). All weather time series records may suffer from inhomogeneities; their use in climatology requires homogenization. In this work we attempt a preliminary homogenization of the cloud cover time series of the Hellenic National Weather Service (HNMS) network. Data come from 36 meteorological stations, and cover the period from 1975 to 2004. Raw data comprise (synoptic) hourly cloud cover observations which we subjected to quality control before producing daily and then monthly average cloud cover time series. For this homogenization exercise we used the HOMER software tool

A combined approach involving ampelographic description, berry oenological traits and molecular analysis to study native grapevine varieties of Greece

A combined approach involving phenotypical characterization (ampelographic description and oenological traits) and molecular analysis was applied on 91 accessions of native Greek grape varieties plus 3 references, all conserved in the Ampelographic Collection of the Aristotle University of Thessaloniki. The accessions were described in accordance to 48 OIV descriptors. Their berry oenological traits were determined at maturity to detect a high juice sugar concentration in most of the assessed varieties, whereas the titratable acidity was found to be extremely low, particularly in the white accessions. Moreover, skin anthocyanin and phenolic content fluctuated from 0.09 to 39.4 mg∙g-1 f.w. and from 2.05 to 30.65 mg∙g-1 f.w. respectively, whereas seed phenolic content was in the range of 2.83 and 32.72 mg∙g-1 f.w. Finally, the discriminative SSR analysis confirmed the differences and similarities among the analyzed varieties as can be evinced from the phylogenetic analysis where close genetic relationship has been detected between 'Fokiano' and 'Armeletousa', 'Moschato Spinas' and 'Moschato Samou', 'Vilana' and 'Asprouda Patron', and 'Mouchtouri' and 'Mavro Spetson'. In all these occasions, the parts of each pair possess similar morphological characteristics

An Operational System For Monitoring Oil Spills In The Mediterranean Sea: The PROMED System

The primary objective of this work was the development of an operational system for early detection of oil-spills, monitoring of their evolution, and provision of support to responsible Public Authorities during cleanup operations, based on Remote Sensing and GIS technologies. In case of emergency, the principal characteristics of the oil spill are defined with the aid of a space-borne synthetic aperture radar (SAR). The transport, spreading and dispersion of the oil spill is subsequently simulated on the basis of wind forecasts of the area. The use of thematic maps of protected, fishing and urban areas, and regions of high tourism allows the better assessment of the impact of an oil spill on the areas to be affected in terms of environmental sensitivity. Finally, reports are generated notifying port authorities, the media, and local organizations to be potentially affected by the presence of the oil spill. The pilot site for testing the PROMED System in Greece is the island of Crete

Debatable results of surgery for lung cancer in a patient with long existing pulmonary metastases from differentiated thyroid carcinoma

Introduction: The appropriate following treatment in a patient with a new presented non-small cell lung cancer (NSCLC) and history of chronic lung metastases of thyroid origin has never been reported. In such cases, the presence of long­standing thyroid metastatic disease with proven “limited malignant potential” could be considered as a minor treatment problem justifying one’s the decision to focus on the primary lung carcinoma as the only serious threat for the patient’s life.Case report: We report the surgical treatment of a new presented NSCLC in a patient with chronic lung metastases of thyroid origin and we present all the diagnostic, staging and treatment problems.Conclusion: The therapeutic results of our surgical approach were not encouraging. This could be owed to our staging prob­lems of NSCLC and the well documented limited immunological response of such patients with multiple neoplasms

Concomitant Radiofrequency ??? Microwave Ablation and Atrial Septal Defect Repair

Atrial fibrillation (AF) is the most frequent form of atrial arrhythmias in adults with congenital heart disease. Some serious complications are related with the presence of AF after surgery. Because of the complexity and the risk of bleeding, the Maze III procedure has been largely replaced by alternative energy sources. A patient with multiple atrial septal defects (ASD) and AF underwent surgical closure with autologous pericardial patch and bipolar radiofrequency and microwave ablation