Investigating the functional roles of occipital face area and lateral occipital cortex with transcranial magnetic stimulation

This thesis investigates the causal role of two extra-striate visual regions, the lateral occipital (LO) cortex and the occipital face area (OFA), in certain visual processes. Firstly, I examined whether these areas are causally implicated in the perception of bilateral visual symmetry. Despite the ubiquitous presence of this feature in the external world, the neural basis underlying its detection is not fully known. In Studies I and II,this issue was explored by disrupting the activity of LO and OFA with fMRI-guided transcranial magnetic stimulation (TMS) while participants discriminated between symmetric and nonsymmetric dot configurations and between perfectly symmetric and normal (i.e. somewhat non symmetric) faces. The results showed that rightOFA plays a causal role in detection of symmetry in both configurations of dots and faces whereas LO exclusively in the former, with the rightLO showing greater involvement relative to the homologous region in the left hemisphere. As symmetry is extracted in a holistic manner (i.e. through a parallel global analysis of the stimulusrather than via a serial point-by-point comparisonof the local elements), Study III examined whether rightOFA is involved, more generally, in visual detection based on holistic encoding and, if so, whether its role is restricted to faces or extends also to non-face stimuli. To examine this issue, rightOFA and rightLO were stimulated with fMRI-guided TMS meanwhile participants were asked to detect Mooney faces and non-face images, a class of stimuli which are known to be perceived through holistic processes. The results showed that rightOFA is causally involved in detection of both Mooney faces and objects. Taken together, this thesis sheds new light on the functions of LO and OFA in visual perception. Firstly, it demonstrates that both of these regions are causally involved in holistic processes, including detection of symmetry. Secondly, it is shownthat OFA s role in holistic processing extends to both face and non-face stimuli, suggesting that this region is not strictly face-selective.Tässä väitöskirjatyössä tutkitaan kahden myöhäisen näköaivokuoren alueen (lateral occipital cortex (LO) ja occipital face area (OFA)) kausaalista roolia tietyissä visuaalisissa prosesseissa. Ensiksi tutkittiin, osallistuvatko nämä alueet kausaalisesti bilateraalisen symmetrian havaitsemiseen. Huolimatta siitä, että symmetriaa on läsnä kaikkialla ympäröivässä maailmassa, sen havaitsemisen hermostollinen perusta ei ole vielä täysin tunnettu. Osatutkimuksissa I ja II asiaa tutkittiin häiritsemällä koehenkilöiden aivojen aktiivisuutta alueilla LO ja OFA fMRI-ohjatun trankraniaalisen magneettistimulaation (TMS) avulla, samalla kun he erottelivat symmetrisiä ja epäsymmetrisiä pistekuvioita sekä täysin symmetrisiä ja normaaleja (jonkin verran epäsymmetrisiä) kasvoja toisistaan. Tulokset osoittivat, että oikeanpuoleisella OFA:lla on kausaalinen rooli sekä pistekuvioiden että kasvojen symmetrian havaitsemisessa, kun taas LO:lla pelkästään edellisessä. Oikeanpuoleisen LO:n osallistumisen havaittiin olevan lisäksi voimakkaampaa suhteessa vastaavaan alueeseen vasemmassa aivopuoliskossa. Koska symmetria havaitaan holistisesti (havaitun ärsykkeen globaalin rinnakkaisen analyysin perusteella paikallisen piste pisteeltä vertailun sijaan), III osatyössä selvitettiin osallistuuko oikeanpuoleinen OFA yleisemmin visuaaliseen havaitsemiseen holistiseen enkoodaukseen perustuen, ja onko sen rooli rajoittunut pelkästään kasvoärsykkeisiin. Tämän tutkimiseksi oikeanpuoleista OFA:ta ja LO:ta stimuloitiin fMRI-ohjatulla TMS:lla koehenkilöiden tarkkaillessa n.k. Mooney kasvoja ja kuvia, joita molempia tiedetään prosessoitavan holistisesti. Tulokset osoittivat, että oikeanpuoleinen OFA osallistuu kausaalisesti sekä Mooney kasvojen että objektien tarkasteluun. Tämä väitöskirja laajentaa ymmärrystä LO ja OFA alueiden toiminnasta visuaalisessa havaitsemisessa. Ensiksi, se demonstroi, että molemmat näistä alueista osallistuvat kausaalisesti holistiseen prosessointiin, sisältäen myös symmetrian havaitsemisen. Toiseksi, työssä osoitetaan, että OFA:n rooli holistisessa prosessoinnissa käsittää sekä kasvo- että muut ärsykkeet, ehdottaen että alue ei ole tiukasti kasvoselektiivinen

Vapour - Liquid Equilibrium measurements of CO2 based mixtures: Experimental apparatus and testing procedures

At present, the accurate evaluation of the thermo-physical behaviour of multicomponent fluids represents a crucial element for studying and simulating low CO2 emission energy conversion technologies. In order to extend the range of application of the available thermodynamic models, an intense experimental research activity has been performed in recent years. The main purpose of this paper is to describe the experimental and modelling procedures applied by the authors to measure and to analyse data extracted from the Vapour-Liquid Equilibrium apparatus recently installed at LEAP laboratory. This test rig allows the characterization of mixture phase equilibrium properties on the basis of the static-analytical method, within the pressure and temperature ranges of 0-20 MPa and -60-200°C. Finally, the paper reports the most relevant features and the main guidelines for the instruments calibration procedures. © 2013 The Authors

Mujeres asalariadas en el cinturón frutihortícola marplatense. Trabajo, trabajadoras y hogares

El objetivo de este artículo es analizar la participación femenina asalariada en el mercado laboral frutihortícola del Partido de General Pueyrredón y su articulación con el trabajo doméstico teniendo en cuenta las características de los hogares de las trabajadoras. En este espacio productivo se constata el trabajo transitorio femenino en la actividad hortícola intensiva –que se practica a campo y bajo cubierta– y en cultivos frutícolas no tradicionales. Las mujeres participan en labores culturales básicas, fundamentalmente, en la cosecha y en la selección, acondicionamiento y empaque de frutas y verduras. Se explora cómo las mujeres despliegan distintas estrategias para compatibilizar el mundo laboral y el mundo familiar y cómo las responsabilidades en las tareas domésticas y de reproducción condicionan sus posibilidades de inserción laboral

Wage work for females in the fruit and vegetable belt of Mar del Plata

El objetivo de este artículo es caracterizar las formas de inserción laboral de mujeres, que aparecen como mano de obra transitoria, en el mercado de trabajo frutihortícola marplatense. El trabajo femenino asalariado está presente en la actividad hortícola que se practica a campo y bajo cubierta y en cultivos frutícolas no tradicionales. La investigación nos ha permitido indagar cómo y por qué estas mujeres se insertan en la actividad agrícola, identificar los procesos laborales específicos que requieren su fuerza de trabajo, así como las modalidades de remuneración y la complementación con otras actividades económicas. La perspectiva de género en el análisis de la participación laboral pone en juego múltiples dimensiones de las relaciones laborales. Desde este enfoque, se procura examinar la participación de las mujeres en las actividades remuneradas, explorando algunos de los rasgos que la configuran.The purpose of this paper is to characterize female job placements in the fruit and vegetable job market of Mar del Plata, in which women’s workforce appears as temporary. Wage work for females is very much present in both indoor and outdoor vegetable farming as well as in non-traditional fruit farming. Our research has enabled us to look into how and why these women enter the vegetable farming activity, as well as to identify the specific labor processes requiring their workforce, the modes of remuneration and the way this activity complements other economic activities. The gender perspective in labor participation analysis puts various work relations dimensions into play. With this approach, we try to examine women’s participation in wage earning activities, exploring some of its organizational features.Departamento de Geografí

Beta-diversity and stressor specific index reveal patterns of macroinvertebrate community response to sediment flushing

Abstract Anthropogenic increase of fine sediment loading is one of the main pressures for rivers worldwide. Particularly, Alpine streams are increasingly facing this issue due to sediment flushing operations from hydropower reservoirs, aimed at recovering storage for preserving electricity generation. Although Controlled Sediment Flushing Operations (CSFOs) are becoming increasingly frequent, ecological indicators to adequately assess and monitor their impact on the stream ecosystem have been poorly developed. In this work, we aimed to perform a screening of currently available biomonitoring tools to evaluate the CSFO effects on the riverine biota and adequately assess its recovery, starting from the recognition of the main ecological mechanisms triggered by the mentioned activities on benthic macroinvertebrate communities. We used two independent datasets concerning two reservoirs in the central Italian Alps to investigate the temporal effects of CSFOs repeated for four consecutive years (case-study I), and the impact of a single CSFO at a seasonal scale through a before/after-control/impact approach (case-study II). Initially, we quantified the CSFO impact on the richness and beta-diversity of macroinvertebrate communities by combining multivariate and univariate statistical techniques. Then, we compared the performance of the Siltation Index for LoTic EcoSystems (SILTES), recently developed for detecting siltation impact in Alpine streams, with that of the generic index currently adopted to assess the ecological status (sensu Water Framework Directive) of the Italian rivers, and of another sediment-specific index, but developed for a different bio-geographical area. The analysis of the two case-studies demonstrated that the nestedness (i.e. taxa loss) is the primary source of biological impairment caused by CSFOs. Moreover, we found that SILTES was more effective than the other indices because of its strong correlation with the nestedness, and since it properly discriminated impaired and pristine conditions, at both multi-annual and seasonal scale. In the first case-study, a threshold in the temporal trend of this index was detected, indicating a recovery within three months. In the second one, SILTES showed a recovery to pre-event seasonal values after nine months from the CSFO, due to larger and more persistent sediment deposition. This study demonstrates that SILTES could be adopted as a benchmark to improve the management of CSFOs from an ecological viewpoint. Our findings can be extended to the management of other sediment-related activities affecting mountainous streams worldwide, and, more generally, the adopted approach can be replicated for developing new ecological tools to manage other disturbances to river environments

Nonintegrating Lentiviral Vector-Based Vaccine Efficiently Induces Functional and Persistent CD8+ T Cell Responses in Mice

CD8+ T cells are an essential component of an effective host immune response to tumors and viral infections. Genetic immunization is particularly suitable for inducing CTL responses, because the encoded proteins enter the MHC class I processing pathway through either transgene expression or cross-presentation. In order to compare the efficiency and persistence of immune response induced by genetic vaccines, BALB/c mice were immunized either twice intramuscularly with DNA plasmid expressing a codon-optimized HIV-1 gp120 Envelope sequence together with murine GM-CSF sequence or with a single immunization using an integrase defective lentiviral vector (IDLV) expressing the same proteins. Results strongly indicated that the schedule based on IDLV vaccine was more efficient in inducing specific immune response, as evaluated three months after the last immunization by IFNγ ELISPOT in both splenocytes and bone marrow- (BM-) derived cells, chromium release assay in splenocytes, and antibody detection in sera. In addition, IDLV immunization induced high frequency of polyfunctional CD8+ T cells able to simultaneously produce IFNγ, TNFα, and IL2

Successful Immunization with a Single Injection of Non-integrating Lentiviral Vector

We evaluated the ability of an integrase (IN)-defective self-inactivating lentiviral vector (sinLV) for the delivery of human immunodeficiency virus-1 (HIV-1) envelope sequences in mice to elicit specific immune responses. BALB/c mice were immunized with a single intramuscular injection of the IN-defective sinLV expressing the codon optimized HIV-1 JR-FL gp120 sequence, and results were compared with those for the IN-competent counterpart. The IN-defective sinLV elicited specific and long-lasting immune responses, as evaluated up to 90 days from the immunization by enzyme-linked immunosorbent spot (ELISPOT) and intracellular staining (ICS) for interferon- γ (IFN- γ ) assays in both splenocytes and bone marrow (BM) cells, chromium release assay in splenocytes, and antibody detection in sera, without integration of the vector into the host genome. These data provide evidence that a single administration of an IN-defective sinLV elicits a significant immune response in the absence of vector integration and may be a safe and useful strategy for vaccine development

Quercetin Treatment Ameliorates Systemic Oxidative Stress in Cirrhotic Rats

Our aim was to investigate whether the antioxidant quercetin protects against liver injury and ameliorates the systemic oxidative stress in rats with common bile duct ligation. Secondary biliary cirrhosis was induced through 28 days of bile duct obstruction. Animals received quercetin (Q) after 14 days of obstruction. Groups of control (CO) and cirrhotic (CBDL) animals received a daily 50 mg/kg body weight i.p. injection of quercetin (CO + Q; CBDL + Q) or vehicle (CO; CBDL). Quercetin corrected the reduction in superoxide dismutase (SOD), catalase CAT, and glutathione peroxidase GPx activities and prevented the increase of thiobarbituric acid reactive substances (TBARS), aminotransferases, and alkaline phosphatase in cirrhotic animals. Quercetin administration also corrected the reduced total nitrate concentration in the liver and prevented liver fibrosis and necrosis. These effects suggest that quercetin might be a useful agent to preserve liver function and prevent systemic oxidative stress

A relevant long-term impact of the circulation of a potentially contaminated vaccine on the distribution of scrapie in Italy. Results from a retrospective cohort study

A sudden increase in the incidence of scrapie in Italy in 1997 was subsequently linked to the use of a potentially infected vaccine against contagious agalactia. The relative risk for the exposed farms ranged between 6 and 40. The aim of this study was to assess the long-term impact of exposure to the potentially scrapie-contaminated vaccine on the Italian classical scrapie epidemic. We carried out a retrospective cohort study, fitting mixed-effects Poisson regression models, dividing national geographic areas into exposure categories on the basis of the vaccine circulation levels. We took into account the sensitivity of the surveillance system applied in the different areas. The population attributable fraction (PAF) was used to assess the impact on the total population of farms associated with the effect of circulation of the vaccine. The provinces where the vaccine was more often sold were noted to have a higher level of disease when compared to those provinces where the vaccine was sold less often (incidence rate ratio [IRR]: 2.7; 95% confidence interval [CI]: 1.1-6.5). The population attributable fraction was high (68.4%). Standardization techniques allowed to account for the potential of geographical variability in the sensitivity of the Italian surveillance system. Although the number of the directly exposed farms was limited, an important long-term impact of the vaccine circulation could be quantified in terms of secondary outbreaks likely due to the exchange of animals from directly exposed flocks