Modelling local winds over the Salento peninsula

A three-day mesoscale numerical simulation has been performed over the narrow Salento peninsula (south-eastern Italy) during summer conditions characterised by weak synoptic forcing. These atmospheric conditions favour the development of complex sea-breeze systems and convergence zones on the peninsula. The aim of this work is to investigate the ability of an atmospheric mesoscale model to reproduce the surface fields of meteorological variables in the presence of local-scale forcing and breeze circulations, which are fundamental in applications such as air pollution modelling and nowcasting. The modelled fields have been compared with available surface measurements and sodar data. Results indicate that the model can simulate the general mean wind field in a realistic way. The diurnal evolution of the wind is well reproduced and the maximum deviations mostly occur during the night, being associated with calm conditions. Statistical analysis indicates that the typical mean bias is found to be about 1 m s−1 for hourly averaged wind speed, less than 20° for wind direction and about 1°C for temperature. The root mean square error (rmse) varies from 1 to 3 m s−1 for wind speed, from 50° to 70° for wind direction, and is about 2.4°C for temperature. All the values of the numerical indexes are within ranges which are characteristic of those found for other state-of-the-art models applied to similar cases studies. Despite a good overall agreement between predictions and observations, some discrepancies were found in the individual profiles due both to the limited spatial representation of the local details and to the complex wind field which makes the space–time matching between the model and the observations quite critical. The structures of the thermal mixed layer and the breeze convergence zone are similar to numerical studies relative to more idealised conditions. Copyright © 2004 Royal Meteorological Societ

Effect of cytochalasin B on the induction of chromosome missegregation by colchicine at low concentrations in human lymphocytes

The aim of the present work was to investigate the possible interference of cytochalasin B (cyt B) with low concentration treatment with colchicine in the induction of chromosome/chromatid loss and micronuclei in human lymphocytes mitotically activated in vitro. Thus, cells from a single female donor were treated with colchicine (10 or 25 nM, from 24 h after PHA addition to fixation at 66 h) either in the presence or absence of cyt B. Single lagging chromosomes/chromatids were scored in bipolar ana-telophases and greater damage (disrupted and c-anaphases) was scored in cells at anaphase. Micronuclei were scored in the first 4000 nuclei observed in both cyt B-treated (in mononucleate and binucleate cells) and untreated cultures. With the same criterion, FISH analysis was performed on 2000 nuclei where chromosome 7 and 11 centromeric DNA probes were used in pairs. Our results showed that: (i) the frequency of laggards and of micronuclei increased with colchicine concentration but in the presence of cyt B there was a lower frequency of both (with a mean reduction of ~ 49%); (ii) FISH analysis showed a colchicine concentration-dependent increase in nuclei with three spots for chromosome 7; (iii) a colchicine concentration-dependent increase in tetraploid cells was observed. This increase was particularly remarkable (5-fold) in cells grown in the presence of cyt B compared with cyt B-untreated cells. The observed 'cyt B effects' can be explained if it is assumed that in cytokinesis-blocked cells there is a shorter distance between the poles. As a consequence: (i) laggards would be engulfed in the nearest daughter nucleus with a consequent lower induction of micronuclei; (ii) segregating sister chromatids in heavily impaired anaphases would not travel a sufficient distance to give rise to two daughter nuclei, leading to an increased frequency of polyploid nuclei

Neuromorphic decoding of spinal motor neuron behaviour during natural hand movements for a new generation of wearable neural interfaces

We propose a neuromorphic framework to process the activity of human spinal motor neurons for movement intention recognition. This framework is integrated into a non-invasive interface that decodes the activity of motor neurons innervating intrinsic and extrinsic hand muscles. One of the main limitations of current neural interfaces is that machine learning models cannot exploit the efficiency of the spike encoding operated by the nervous system. Spiking-based pattern recognition would detect the spatio-temporal sparse activity of a neuronal pool and lead to adaptive and compact implementations, eventually running locally in embedded systems. Emergent Spiking Neural Networks (SNN) have not yet been used for processing the activity of in-vivo human neurons. Here we developed a convolutional SNN to process a total of 467 spinal motor neurons whose activity was identified in 5 participants while executing 10 hand movements. The classification accuracy approached 0.95 ±0.14 for both isometric and non-isometric contractions. These results show for the first time the potential of highly accurate motion intent detection by combining non-invasive neural interfaces and SNN

Indirect mitotic nondisjunction in Vicia faba and Chinese hamster cells

The hypothesis of indirect mitotic nondisjunction was tested in plant and mammalian cells. This hypothesis states that micronuclei derived from lagging chromosomes or chromatids are able to perform DNA synthesis and undergo mitotic condensation synchronously with main nuclei. Hence, as chromosomes, they can be moved to spindle poles together with the chromosomes of the main nuclei during mitosis. In that way chromosomes "lost" as micronuclei can be reincorporated in the main nuclei. In order to test this, both Vicia faba meristematic cells and cells of a Chinese hamster line (Cl-1) were treated with low doses of colchicine. Mitotic anomalies, micronuclei and cells with a polyploid or aneuploid karyotype were scored at different fixation times. A detailed analysis was performed on single chromosome misdistributions, as well as on micronuclei and cells with aneuploid karyotypes derived from single chromosome misdistributions. Indirect mitotic nondisjunction was shown to play a primary role in the origin of aneuploid karyotypes in Vicia faba, but not in Cl-1 cells

A GIS BASED AIR QUALITY SYSTEM FOR THE APULIA REGION, SOUTHERN ITALY

Apulia region in the Southern Italy is frequently characterised by high photochemical pollution levels in the warm period and by high levels of PM10 and NO2 in the winter season. Emissions in the area derive essentially from urban, shipping and industrial activities. The main industrial activities are related to the iron and steel industry (one of the largest in Europe) on the western coast and to two coal power plants on the eastern coastline. A GIS based air quality system has been developed to support local authorities in air quality management for the region. The proposed modeling system is based on RAMS (Pielke et al., 1992) and CALMET (Scire et al., 2000) meteorological models and on CALPUFF (Scire et al., 2000)/ CALGRID (Yamartino et al., 1989) dispersion models. Diffuse emissions for the domain were obtained from the national CORINAIR data base (www.sinanet.apat.gov.it) and were preprocessed by a new-developed tool GEM-PP (Gis EMission Pre-Processor) based on open source GIS. Point sources emissions are obtained by local inventory. Meteorological and dispersion simulations were performed for the year 2005. Predictions have been compared with concentration data from the air quality monitoring network. Results evidence a good correlation between predictions and measurements for O3, NOx, SO2 with most of data in factor of two of the measurements for rural stations and a tendency to underestimate measured data in urban stations. Overall the model tends to underestimate CO measurements. The uncertainty of the predictions are analysed and discussed in terms of the emission calculations, dispersion modelling and monitoring site

Clastogenicity and aneuploidy in newborn and adult mice exposed to 50 Hz magnetic fields.

Purpose:?To detect possible clastogenic and aneugenic properties of a 50 Hz, 650 ?T magnetic field. Materials and methods:?The micronucleus test with CREST (Calcinosis, Raynaud's phenomenon, Esophageal dismotility, Sclerodactility, Telangectasia) antibody staining was performed on liver and peripheral blood sampled from newborn mice exposed to an ELF (Extremely Low Frequency) magnetic field during the whole intra-uterine life (21 days), and on bone marrow and peripheral blood sampled from adult mice exposed to the same magnetic field for the same period. Results:?Data obtained in newborn mice show a significant increase in micronuclei frequencies. In absolute terms, most of the induced micronuclei were CREST-negative (i.e., formed by a chromosome fragment). However, in relative terms, ELF exposure caused a two-fold increase in CREST-negative micronuclei and a four-fold increase in CREST-positive micronuclei (i.e., formed by a whole chromosome). No significant effect was recorded on exposed adults. Conclusions:?These findings suggest the need for investigation of aneugenic properties of ELF magnetic fields in order to establish a possible relationship to carcinogenesis

Status report of a systematic investigation on low-dose ionizing radiation effects in mammalian cells

In the last 15 years a growing interest in the biological effects induced by low doses of ionizing radiation has arisen in the scientific community, due to an increasing number of experimental evidences showing a plethora of non-linear effects occurring after low-dose irradiations. In particular, hyper-radiosensitivity and induced radioresistance (HRS/IRR) have been reported after exposure to low- and high-LET radiation, in human (normal and tumoural) and other mammalian cells in vitro. In this framework, Chinese hamster V79 cells, human primary fibroblasts (HFFF2) and murine embryonic fibroblasts (MEFs) were irradiated with broadbeams of protons in the dose range 0.1–5.0Gy and at 1 Gy/min dose-rate. Cellular response has been evaluated in terms of cell survival, micronuclei induction, chromosomal aberrations and telomere length alterations. For comparison purpose, the same end-points were studied after X/γ-rays irradiation

Objective climatology of cyclones in the Mediterranean region: a consensus view among methods with different system identification and tracking criteria

The Mediterranean storm track constitutes a well-defined branch of the North Hemisphere storm track and is characterised by small but intense features and frequent cyclogenesis. The goal of this study is to assess the level of consensus among cyclone detection and tracking methods (CDTMs), to identify robust features and to explore sources of disagreement. A set of 14 CDTMs has been applied for computing the climatology of cyclones crossing the Mediterranean region using the ERA-Interim dataset for the period 1979–2008 as common testbed. Results show large differences in actual cyclone numbers identified by different methods, but a good level of consensus on the interpretation of results regarding location, annual cycle and trends of cyclone tracks. Cyclogenesis areas such as the north-western Mediterranean, North Africa, north shore of the Levantine basin, as well as the seasonality of their maxima are robust features on which methods show a substantial agreement. Differences among methods are greatly reduced if cyclone numbers are transformed to a dimensionless index, which, in spite of disagreement on mean values and interannual variances of cyclone numbers, reveals a consensus on variability, sign and significance of trends. Further, excluding ‘weak’ and ‘slow’ cyclones from the computation of cyclone statistics improves the agreement among CDTMs. Results show significant negative trends of cyclone frequency in spring and positive trends in summer, whose contrasting effects compensate each other at annual scale, so that there is no significant long-term trend in total cyclone numbers in the Mediterranean basin in the 1979–2008 period