Travailleurs étrangers et travail irrégulier en Italie: évidences sur la base de la régularisation de 2002

Objectif de ce travail est de montrer en quelle mesure la régularisation 2002 reproduit une géographie spécifique de l’insertion des immigrés dans l’économie souterraine au niveau local. Notamment, en utilisant les données des étrangers régularisés par province de présentation des demandes on cherchera à mettre en évidence l’homogénéité ou hétérogénéité des différentes régions du pays par rapport à la typologie de régularisation et aux caractéristiques socioprofessionnelles des régularisés. De plus, on montrera l’existence de liens entre l’emploi de travailleurs étrangers en condition d’irrégularité et certaines caractéristiques des marchés du travail et des systèmes productifs locaux. On se servira de cartogrammes et de technique statistiques telles que l’analyse factorielle et cluster et la régression linéaire multiple

Rich Information in the Acoustic Signals from Feeding and Grazing in Ruminants

Because of their impact on productivity and the environment, feeding behaviour, ingestion and rumination are critical to understand intake in grazing ruminants. Many systems, mainly mechanical, have been developed to measure ingestive behaviour. However, these systems have problems, including mechanical failure and the inability to distinguish between the complex jaw movements of prehension and ingestion (Laca et al., 1994). The sounds generated by these behaviours are rich in information that holds potential not only to distinguish and count behaviours, but also identify aspects of the nature of the foods ingested

The Sound of Chewing

Acoustic biotelemetry has been proposed as a way to count ingestive bites and chews of grazing animals. Recent work has indicated the possibility that detailed analysis of \u27sounds of chewing\u27 contains information about other characteristics of the ingestive process that can be used to study grazing behaviour of free ranging animals (Laca & Wallis DeVries, 2000), or to monitor stall-fed animals in more detail

Evaluation of Cytotoxicity and Genotoxicity of Acacia aroma Leaf Extracts

Acacia aroma, native plant from San Luis, Argentina, is commonly used as antiseptic and for healing of wounds. The present study was conducted to investigate the in vitro cytotoxicity and genotoxicity of hot aqueous extract (HAE) and ethanolic extract (EE) of A. aroma. The cytotoxic activity was assayed by neutral red uptake assay on Vero cell. Cell treatment with a range from 100 to 5000 g/mL of HAE and EE showed that 500 g/mL and 100 g/mL were the maximum noncytotoxic concentrations, respectively. The CC50 was 658 g/mL for EE and 1020 g/mL for HAE. The genotoxicity was tested by the single-cell gel electrophoresis comet assay. The results obtained in the evaluation of DNA cellular damage exposed to varied concentrations of the HAE showed no significant genotoxic effect at range of 1–20 mg/mL. The EE at 20 mg/mL showed moderate genotoxic effect related to the increase of the DNA percentage contained in tail of the comet; DNA was classified in category 2. At concentrations below 5 mg/mL, the results of cytotoxicity and genotoxicity of aqueous and ethanolic extracts of Acacia aroma guarantee the safety at cell and genomic level. However further studies are needed for longer periods including animal models to confirm the findings.Fil: Mattana, Claudia Maricel. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Cangiano, Maria de Los Angeles. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alcaraz, María Luciana. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sosa, A.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Escobar, Franco Matias. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sabini, C.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Sabini, Liliana Ines. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Laciar, Analia Liliana. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentin

Resource heterogeneity and foraging behaviour of cattle across spatial scales

BackgroundUnderstanding the mechanisms that influence grazing selectivity in patchy environments is vital to promote sustainable production and conservation of cultivated and natural grasslands. To better understand how patch size and spatial dynamics influence selectivity in cattle, we examined grazing selectivity under 9 different treatments by offering alfalfa and fescue in patches of 3 sizes spaced with 1, 4, and 8 m between patches along an alley. We hypothesized that (1) selectivity is driven by preference for the forage species that maximizes forage intake over feeding scales ranging from single bites to patches along grazing paths, (2) that increasing patch size enhances selectivity for the preferred species, and that (3) increasing distances between patches restricts selectivity because of the aggregation of scale-specific behaviours across foraging scales.ResultsCows preferred and selected alfalfa, the species that yielded greater short-term intake rates (P < 0.0001) and greater daily intake potential. Selectivity was not affected by patch arrangement, but it was scale dependent. Selectivity tended to emerge at the scale of feeding stations and became strongly significant at the bite scale, because of differences in bite mass between plant species. Greater distance between patches resulted in longer patch residence time and faster speed of travel but lower overall intake rate, consistent with maximization of intake rate. Larger patches resulted in greater residence time and higher intake rate.ConclusionWe conclude that patch size and spacing affect components of intake rate and, to a lesser extent, the selectivity of livestock at lower hierarchies of the grazing process, particularly by enticing livestock to make more even use of the available species as patches are spaced further apart. Thus, modifications in the spatial pattern of plant patches along with reductions in the temporal and spatial allocation of grazing may offer opportunities to improve uniformity of grazing by livestock and help sustain biodiversity and stability of plant communities

Antimicrobial Activity against Escherichia coli of Cu-Ni Nanoalloy and Combination of Ag Nanoparticles, Obtained by Different Method

Escherichia coli, is a pathogenic bacterium that causes serious infections, whose therapeutic treatment is threatened by the emergence of multiple resistance to conventional antibiotics. In recent years, metal nanoparticles (NPs) have been studied for their antimicrobial capacity and their possible applications as an alternative to antibiotics against different pathogens. NPs also vary in synthesis techniques; either by chemical, physical and biological methods. The objective of this work was to study the possible antimicrobial capacity of Cu-Ni nanoalloys obtained by a method called citrate-gel. The antimicrobial capacity of the NPs mentioned above was evaluated in vitro by the agar diffusion method. Most of the NPs evaluated showed antibacterial activity against the strain of E. coli studied. When combining chemical and biological NP, synergistic effects are observed with an increase in antibacterial activity in some cases. We can conclude that NPs derived from chemical and biological synthesis could be used as antimicrobials against E. coli and when these are combined, antibacterial effects increase. In the future, these applications of nanomaterials could be used as an alternative to the use of antibiotics against infections that have limited treatmentsFil: Fernandez, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Illanez, Yamila A.. Universidad Nacional de San Luis. Facultad de Ingeniería y Ciencias Agropecuarias; ArgentinaFil: Fernandez, Gastón. Universidad Catolica de Cuyo - Sede San Luis; ArgentinaFil: Esquivel, Marcelo Ricardo Oscar. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional del Comahue; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cangiano, Maria de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; Argentin