765 research outputs found
Movement ecology of the white seabream Diplodus sargus across its life cycle: a review
The white seabream Diplodus sargus (L., 1758) (Osteichthyes, Sparidae) is a littoral species living mainly in rocky habitats and distributed in the eastern Atlantic and the Mediterranean. This species is targeted by artisanal and recreational fisheries and presents a high commercial importance. Although classified by IUCN as a "least concern" species, it has been the object of marine ranching and restocking initiatives to counteract locally intense exploitation. Here, we review the current knowledge on the movement ecology of white seabream given the relevance of animal movement in ecological and behavioral studies and their potential application in management and conservation. The literature on this topic was analyzed in order to summarize the results of past research and to identify the gaps that still exist on the matter. We reviewed a total of 27 papers focusing on the movement ecology of white seabream, where acoustic telemetry (n = 12), underwater visual observation and traditional tagging (n = 6), genetic analysis (n = 6), and otolith microchemistry (n = 3) were used. While the first three methods were applied to juvenile and adult fish, the last one was also used with larvae, which have been the object of experimental trials to ascertain their swimming abilities. The largest amount of information on activity rhythms (diurnal with a few exceptions), movement patterns (short distances), homing (ability to come back to the capture site), site fidelity (high), and home range (< 200 ha on average and highly related with seabed morphology) were obtained through acoustic telemetry, whose main limitation is the minimum body size required for its application. The environmental variables found to affect movement patterns in this species are water temperature (which triggers spawning-based vertical movements), local sea conditions (which affect short-scale movements in juveniles), and the main seabed features (orientation and habitat type). The main gaps identified, which need more extensive research and some technological improvements, include the study of the effects of environmental variables on fish movements and further investigations on the movement patterns of juveniles.info:eu-repo/semantics/publishedVersio
Cytochrome P450 2E1 variable number tandem repeat polymorphisms and health risks: A genotype-phenotype study in cancers associated with drinking and/or smoking
Cytochrome P450 2E1 (CYP2E1) is one of the main enzymes involved in the oxidation of ethanol and in the transformation of a number of potentially dangerous compounds. It has various polymorphic sites, one of which is a variable number tandem repeat (VNTR) polymorphism previously described in the 5'-flanking region. The aim of this study was to investigate the genotype-phenotype association between CYP2E1 VNTR polymorphisms and risky health habits in healthy subjects and to analyze the associations between these polymorphisms with drinking- and/or smoking-related cancers. We analyzed 166 healthy subjects by genotyping for the CYP2E1 VNTR polymorphism associated with drinking and/or smoking habits by the more sensitive restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) method, using the NlaIV restriction enzyme. Sixty cases of pancreatic adenocarcinoma (PA) and 66 with hepatocellular carcinoma (HCC), were also genotyped. Statistical analysis was carried out to investigate the genotype-phenotype associations and to compare certain genotypes and cancer. We found 7 genotypes both in the healthy subjects and patients. The A1/A1 genotype was observed to be mainly associated with non-drinkers and -smokers (87.5 and 75.0%, respectively); moreover it was never found in the PA or HCC patients. Conversely, a weak association between A2/A3 with smokers (45.8%) and A4/A4 with drinkers (53.9%) was detected. In addition, the A4/A4 genotype was found to be significantly associated to PA [odds ratio (OR)=3.25; 95% confidence interval (CI) 1.21-7.50]. Our data demonstrate that certain CYP2E1 VNTR genotypes are associated with drinking and/or smoking habits; consequently, they may contribute either to the decreased or increased risk of developing drinking- and/or smoking-related cancers. In particular, we hypothesize that the A1/A1 VNTR genotype may have a protective role against drinking- and/or smoking-related cancers, and that A4/A4 may be a high-risk genotype during the early stages of cancer
Spatial distribution of demersal fishery resources, environmental factors and fishing activities in GSA 15 (Malta Island)
The FAO–MedSudMed Regional Project has promoted research on the improvement of knowledge on fishery ecosystems, with a view to the sustainable management of living marine resources in the central Mediterranean (Straits of Sicily). A pilot study focused on the waters around the Maltese Islands (GSA 15), with the aim of providing a comprehensive overview of the spatial distribution of the different life stages of exploitable demersal fishes in relation to the type and distribution of fishing, as well as to the oceanographic factors characteristic of the area of study. Critical zones for their role in the ecology of the main demersal fishery target species were investigated using species abundance data disaggregated by life stage. Spatial analysis and the application of GIS techniques allowed the identification of preferred habitats (e.g. nursery, feeding and spawning areas) for Merluccius merluccius, Mullus barbatus, Parapenaeus longirostris, Raja clavata and Raja miraletus. The impact of fishing on these species was assessed, particularly in terms of fish assemblages. The transport paths of early life stages were also hypothesized on the basis of oceanographic factors typical of the area. The results revealed that the spatial distribution of the main fishery resources overlaps the limits of the current GSAs. The analysis of oceanographic factors showed that some fishery resources are sustained by young individuals transported from adjacent GSAs. The results also demonstrated that the spatial distribution of the main demersal fishery resources in the Mediterranean GSA 15 straddle other GSAs, in particular as concerns nursery and spawning areas, indicating that some fishery resources are shared. This implies that harmonized fishery management should be applied over a larger area than is implied by the GSA concept. Finally, the study showed how data provided by different methods could be integrated to enhance the available scientific information in a data-limited situation.peer-reviewe
A methodology to reduce the computational effort in 3D-CFD simulations of plate-fin heat exchangers
The analysis of a plate-fin heat exchanger performance requires the evaluation of key parameters such as heat transfer and pressure drop. In this regard, computational Fluid Dynamics (CFD) can be proficiently adopted, at the design stage, to predict the performance of plate-fin heat exchangers. However, these last are often characterized by a complex geometry, such as in the case of plate exchangers with turbulators, leading to a huge computational effort, which often exceeds the available resources. In this study, a numerical methodology for the simulation of plate heat exchangers is proposed, to bypass the limits imposed by the computational cost. The methodology relies on the simulation of a minimal portion of the exchanger (two plates, one per fluid) characterized by periodic boundary conditions (that mimic the presence of several layers). The total heat exchanged is obtained simply multiplying the calculated heat transfer by the number of plate couples composing the device. Moreover, the two plates allow to calibrate porous media which are adopted to rebuild (in a simplified version) the two fluid circuits of the whole exchanger and obtain the overall pressure drop across the device for both the hot and cold fluids.
The proposed approach is validated against experimental data of an oil cooler for automotive application, that is a plate-fin heat exchanger characterized by the presence of turbulators. The numerical outcomes are compared to the experiments in terms of pressure drop and heat transfer for a wide range of volumetric flow rates. Particular attention is devoted to the mesh sensitivity and the adopted computational grid minimizes the number of cells (and, thus, the computational cost), without compromising the accuracy. Moreover, the Reynolds-Stress-Transport turbulence model is accurately selected among the most diffused ones, in order to properly match the test bench data.
The proposed methodology allows to reduce of nearly one order of magnitude the total number of cells required for the simulation of the heat exchanger performance. The heat transfer is predicted with high accuracy, i.e. error is always lower than 4%. As for the pressure loss, the deviation compared to the experiments increases up to nearly 15% (for one of the simulated conditions) but it is considered still acceptable
ALLELIC VARIANTS OF CYP2E1 GENE IN HEPATOCARCINOMA PATIENTS AND IN HEPATIC TUMOR CELL LINES
Background and Aims: Hepatic enzyme CYP2E1 is involved in the
metabolism of a number of exogenous and endogenous substances
(i.e. ethanol, drugs and chemical carcinogens). Being polymorphic,
CYP2E1 gene can give different xeno-metabolic capabilities in a
population and it is well known that inadequate or no enzymatic
deactivation of xenobiotics could induce an increased susceptibility
to disease and cancer. In particular, one of the 5 -flanking region
polymorphisms, able to differentiate CYP2E1 gene transcriptional
activity, is caused by the appearance/disappearance of RsaI and
PstI restriction sites, which generates two different alleles, namely
*C1(Rsa+/Pst−) and *C2(Rsa−/Pst+) respectively, reported to be in
complete linkage disequilibrium.
Methods: To confirm the existence of a correlation between some
particular CYP2E1 genotypes/haplotypes and hepatocarcinoma, we
determined CYP2E1 PstI/RsaI genotypes/haplotypes by RFLP-PCR in
a cohort of central western Sicily hepatocarcinoma patients and in
a population of healthy students from the same geographic area.
Results: In hepatocarcinoma patients, modal genotype association
was Rsa++/Pst−−, corresponding to CYP2E1 *C1/*C1 haplotype,
whereas the Rsa+−/Pst−+ association, equivalent to CYP2E1 *C1/*C2
haplotype, resulted to have the lowest frequency both in patients
and in controls. Moreover, both in patients and in controls, noncanonical
genotype associations were frequent and arose from
a no-linkage disequilibrium between the two polymorphic sites.
Other authors reported this finding as a rare occurrence. Thus,
from analysis of only one restriction site, Rsa++ genotype was
approximately 1.5-fold more frequent in patients than in controls,
and the non-canonical Rsa+− genotype was found relatively
frequent in patients. Moreover, HuH7 and HA22T transformed
hepatocarcinoma cell lines also showed the Rsa+− genotype.
Conclusions: These results suggest that the presence in CYP2E1
genotype of at least one allele with an Rsa I restriction site is
correlated with hepatocarcinoma. As this site is known a consensus
sequence for some specific CYP gene transcription factors, like
HNF-1, it may be supposed that a single nucleotide polymorphism
can alter the possibility of HNF-1 to bind CYP2E1 promoter. This
could determine a marked change in the transcriptional activity
of the gene, incompetence in xenobiotic metabolism or in toxic
substance deactivation and an increased susceptibility to neoplastic
diseases, such as hepatocarcinoma
Security Triage: An Industrial Case Study on the Effectiveness of a Lean Methodology to Identify Security Requirements
ABSTRACT Context: Poste Italiane is a large corporation offering integrated services in banking and savings, postal services, and mobile communication. Every year, it receives thousands of change requests for its ICT services. Applying to each and every request a security assessment "by the book" is simply not possible. Goal: We report the experience by Poste Italiane of a lean methodology to identify security requirements that can be inserted in the production cycle of a normal company. Method: The process is based on surveying the overall IT architectures (Security Survey) and then a lean dynamic process (Security Triage) to evaluate individual change requests, so that important changes get the attention they need, minor changes can be quickly implemented, and compliance and security obligations are met. Results: The empirical evaluation conducted for over an year at Poste Italiane shows that the process significantly reduces the time to identify security requirements at the pace of change.Conclusions: The Security Survey and Triage process should thus be embedded in a companyâȂŹs production cycle as mandatory step to manage change requests so that security initiatives are prioritized based on the relevance of the assets and of the business objectives of the company
Monitoraggio delle risorse ittiche e della pesca: indagine sugli spostamenti di specie marine di interesse commerciale e conservazionistico
Il monitoraggio degli spostamenti degli organismi marini è un importante strumento per la comprensione della biologia delle specie ma anche per la conservazione e la tutela degli stock intesi come risorsa. Nel caso dell'applicazione su specie che vivono all'interno di Aree Marine Protette, queste tecniche consentono di verificare l'efficacia della protezione. Questo studio riporta l'applicazione di tecniche di telemetria ultrasonica all'aragosta comune (P. elephas) nell'AMP di Isola delle Femmine. Gli individui catturati all'interno dell'AMP ed ivi rilasciati hanno mostrato uno spiccato homing ed un buon livello di fedeltà al sito. Lo studio inoltre è servito a denunciare lo stato attuale di scarsa protezione e suggerisce una riperimetrazione dei confini dell'AMP
Deliverable 1.1 review document on the management of marine areas with particular regard on concepts, objectives, frameworks and tools to implement, monitor, and evaluate spatially managed areas
The main objectives if this document were to review the existing information on spatial management of marine areas, identifying the relevant policy objectives, to identify parameters linked to the success or failure of the various Spatially Managed marine Areas (SMAs) regimes, to report on methods and tools used in monitoring and evaluation of the state of SMAs, and to identify gaps and weaknesses in the existing frameworks in relation to the implementation, monitoring, evaluation and management of SMAs. The document is naturally divided in two sections: Section 1 reviews the concepts, objectives, drivers, policy and management framework, and extraneous factors related to the design, implementation and evaluation of SMAs; Section 2 reviews the tools and methods to monitor and evaluate seabed habitats and marine populations.peer-reviewe
Piano di Lavoro Nazionale Raccolta Dati Alieutici 2017-2019 Rapporto tecnico annuale
Campionamento biologico delle specie demersali e dei piccoli pelagici (GSA16
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