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

Identification and validation of reference genes for quantitative RT-PCR normalization in wheat

<p>Abstract</p> <p>Background</p> <p>Usually the reference genes used in gene expression analysis have been chosen for their known or suspected housekeeping roles, however the variation observed in most of them hinders their effective use. The assessed lack of validated reference genes emphasizes the importance of a systematic study for their identification. For selecting candidate reference genes we have developed a simple <it>in silico </it>method based on the data publicly available in the wheat databases Unigene and TIGR.</p> <p>Results</p> <p>The expression stability of 32 genes was assessed by qRT-PCR using a set of cDNAs from 24 different plant samples, which included different tissues, developmental stages and temperature stresses. The selected sequences included 12 well-known HKGs representing different functional classes and 20 genes novel with reference to the normalization issue. The expression stability of the 32 candidate genes was tested by the computer programs geNorm and NormFinder using five different data-sets. Some discrepancies were detected in the ranking of the candidate reference genes, but there was substantial agreement between the groups of genes with the most and least stable expression. Three new identified reference genes appear more effective than the well-known and frequently used HKGs to normalize gene expression in wheat. Finally, the expression study of a gene encoding a PDI-like protein showed that its correct evaluation relies on the adoption of suitable normalization genes and can be negatively affected by the use of traditional HKGs with unstable expression, such as actin and α-tubulin.</p> <p>Conclusion</p> <p>The present research represents the first wide screening aimed to the identification of reference genes and of the corresponding primer pairs specifically designed for gene expression studies in wheat, in particular for qRT-PCR analyses. Several of the new identified reference genes outperformed the traditional HKGs in terms of expression stability under all the tested conditions. The new reference genes will enable more accurate normalization and quantification of gene expression in wheat and will be helpful for designing primer pairs targeting orthologous genes in other plant species.</p

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

The PDI (Protein Disulfide Isomerase) gene family in wheat.

The PDI (Protein Disulfide Isomerase) gene family includes several members whose products are responsible for diversified metabolic functions. PDI and PDI-like proteins differ for number and position of thioredoxin-like (TRX-like) active (a type) and inactive (b type) domains, for presence/absence of other domains and of the KDEL signal of retention in the endoplasmic reticulum (ER). The phylogenetic analysis of typical PDI and PDI-like protein sequences resolved them into 10 groups (1), 5 of them (I-V) had 2 TRX-like active domains, whereas the remaining ones owned only a single TRX-like active domain (VI-VIII, QSOX and APRL). In particular, QRX and APRL were not included in this study due to their putative non-isomerase enzymatic activities encoded by an additional domain. The aim of the present research was the study of the complexity and diversity of the PDI gene family in wheat, with particular focus on the genes encoding PDIlike proteins structurally similar to TaPDIL1-1 (group I), the first identified and best characterized member of the PDI family, also named typical PDI. The most important function of typical PDI is the formation and isomerization of disulfide bonds during protein folding, which are accomplished by its two active TRX-like sites sharing the characteristic tetrapeptide –CGHC-. Several studies of molecular characterization, expression analysis and cell localisation in rice and maize have suggested the involvement of typical PDI in the assembly and deposition of storage proteins in these species (2, 3, 4). The characterization and chromosome location of the three homoeologous gene sequences encoding typical PDI and of their promoter sequences have been reported previously (5)

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

Relationship between the D genome of hexaploid wheats (AABBDD) and Ae. squarrosa as deduced by seed storage proteins and molecular marker analyses

The electrophoretical analyses of seed storage protein components from the gliadin and glutenin fractions in T. aeslivum ssp. vulgare, compaction, sphaerococcum, macha, vavilovii, and spelta have revealed limited variation at the tightly linked coding loci Gli-D1/Glu-D3, and Glu-D1, located respectively on the short and long arm of chromosome ID, and at the GH-D2 locus, positioned on the short arm of chromosome 6D. Much higher variation was observed, for the same protein components, in the wild diploid Ae. squarrosa, the D genome donor of the aestivum group. Genetic variation in the same wheat subspecies and in Ae. squarrosa has also been evaluated by Southern hybridization of genomic DNAs, which were digested with several restriction enzymes, and hybridized with cloned sequences of genes coding for seed storage proteins. The much higher degree of variation observed for the seed storage protein genes of Ae. squarrosa, in comparison with the variation exhibited by the proteins encoded by the D genome chromosomes of hexaploid wheats, supports the hypothesis that a limited number of crosses gave rise to hexaploid wheats of the aestivum group