Internal polarized gas targets: systematic studies on intensity and correlated effects

The work carried out during the PhD was dedicated to the study of high-density polarized gas targets used in high-energy physics. The thesis is related to the PAX experiment, which aims to produce a beam of polarized anti-protons, by means of spin-filtering with a polarized atomic target. In order to obtain the densities required by high-energy particle physic, gaseous targets are a combination of an Atomic Beam Source and a storage cell. The possibility to improve the various components of the ABS and the storage cell has been evaluated, through dedicated systematic studies, using the facilities available in “Spinlab” of Universit´a di Ferrara. The attenuation of a collimated beam passing through the rest gas of a vacuum system has been studied; different nozzle geometries have been tested (comparing the measured data with the data calculated by simulation programs); design and tests of an new kind of injection tube with internal fins (with the aim of decreasing the conductance of the storage cell without diminishing the acceptance and thus to increase the integrated target thickness). Estimation of the attenuation coefficients and total cross sections have been derived from the measurements of the attenuation of a hydrogen or deuterium beam. This quantities are important for projecting new ABS and to improve the existing ones. A favorable nozzle geometry (called “trumpet”) that increases the beam intensity has been derived from simulations and experimental tests. Tests on the injection tubes with fins did not give positive results when applied to the PAX storage cell geometry; however a azimuthal motion of the atoms of a focused beam emerged from the measurements, a motion that until now has been completely neglected

Phytoremediation opportunities with alimurgic species in metal-contaminated environments

Alimurgic species are edible wild plants growing spontaneously as invasive weeds in natural grassland and farmed fields. Growing interest in biodiversity conservation projects suggests deeper study of the multifunctional roles they can play in metal uptake for phytoremediation and their food safety when cultivated in polluted land. In this study, the responses of the tap-rooted perennial species Cichorium intybus L., Sonchus oleracerus L., Taraxacum officinaleWeb., Tragopogon porrifolius L. and Rumex acetosa L. were studied in artificially-highly Cd-Co-Cu-Pb-Zn-contaminated soil in a pot-scale trial, and those of T. officinale and R. acetosa in critical open environments (i.e., landfill, ditch sediments, and sides of highly-trafficked roads). Germination was not inhibited, and all species showed appreciable growth, despite considerable increases in tissue metal rates. Substantial growth impairments were observed in C. intybus, T. officinale and T. porrifolius; R. acetosa and S. oleracerus were only marginally affected. Zn was generally well translocated and reached a high leaf concentration, especially in T. officinale (~600 mg/kg dry weight, DW), a result which can be exploited for phytoremediation purposes. The elevated Cd translocation also suggested applications to phytoextraction, particularly with C. intybus, in which leaf Cd reached ~16 mg/kg DW. The generally high root retention of Pb and Cu may allow their phytostabilisation in the medium-term in no-tillage systems, together with significant reductions in metal leaching compared with bare soil. In open systems, critical soil Pb and Zn were associated with heavily trafficked roadsides, although this was only seldom reflected in shoot metal accumulation. It is concluded that a community of alimurgic species can serve to establish an efficient, long-lasting vegetation cover applied for phytoremediation and reduction of soil metal movements in degraded environments. However, their food use is not recommended, since leaf Cd and Pb may exceed EU safety thresholds

Profit Shifting by Debt Financing in Europe

This article aims at analyzing the link between subsidiaries’ capital structure and taxation in Europe. First we introduce a trade-off model, which studies a MNCs’ financial strategy and shows how debt policy allows multinational groups to shift profits from low-tax to high-tax jurisdictions. By letting the MNC choose both leverage and the percentage of profit shifting, we depart from the relevant literature which has mainly focused on the latter. Using the AMADEUS dataset we show that: i) subsidiaries’ leverage increases with the statutory tax rate, levied in the country where it operates; ii) this positive effect is lower, the higher the parent company tax rate is. Furthermore, an increase in the parent company’s tax rate is estimated to raise its subsidiaries’ leverage.capital structure, default, multinationals, profit shifting, taxation

Biostimulant Effects of Seed-Applied Sedaxane Fungicide: Morphological and Physiological Changes in Maize Seedlings

Most crops are routinely protected against seed-born and soil-borne fungal pathogens through seed-applied fungicides. The recently released succinate dehydrogenase inhibitor (SDHI), sedaxane\uae, is a broad-spectrum fungicide, used particularly to control Rhizoctonia spp., but also has documented growth-enhancement effects on wheat. This study investigates the potential biostimulant effects of sedaxane and related physiological changes in disease-free maize seedlings (3-leaf stage) at increasing application doses (25, 75 and 150 \u3bcg a.i. seed-1) under controlled sterilized conditions. We show sedaxane to have significant auxin-like and gibberellin-like effects, which effect marked morphological and physiological changes according to an approximate saturation dose-response model. Maximum benefits were attained at the intermediate dose, which significantly increased root length (+60%), area (+45%) and forks (+51%), and reduced root diameter as compared to untreated controls. Sedaxane enhanced leaf and root glutamine synthetase (GS) activity resulting in greater protein accumulation, particularly in the above-ground compartment, while glutamate synthase (GOGAT) activity remained almost unchanged. Sedaxane also improved leaf phenylalanine ammonia-lyase (PAL) activity, which may be responsible for the increase in shoot antioxidant activity (phenolic acids), mainly represented by p-coumaric and caffeic acids. We conclude that, in addition to its protective effect, sedaxane can facilitate root establishment and intensify nitrogen and phenylpropanoid metabolism in young maize plants, and may be beneficial in overcoming biotic and abiotic stresses in early growth stages

Biostimulant Effects of Seed-Applied Sedaxane Fungicide: Morphological and Physiological Changes in Maize Seedlings

Most crops are routinely protected against seed-born and soil-borne fungal pathogens through seed-applied fungicides. The recently released succinate dehydrogenase inhibitor (SDHI), sedaxane®, is a broad-spectrum fungicide, used particularly to control Rhizoctonia spp., but also has documented growth-enhancement effects on wheat. This study investigates the potential biostimulant effects of sedaxane and related physiological changes in disease-free maize seedlings (3-leaf stage) at increasing application doses (25, 75 and 150 μg a.i. seed-1) under controlled sterilized conditions. We show sedaxane to have significant auxin-like and gibberellin-like effects, which effect marked morphological and physiological changes according to an approximate saturation dose-response model. Maximum benefits were attained at the intermediate dose, which significantly increased root length (+60%), area (+45%) and forks (+51%), and reduced root diameter as compared to untreated controls. Sedaxane enhanced leaf and root glutamine synthetase (GS) activity resulting in greater protein accumulation, particularly in the above-ground compartment, while glutamate synthase (GOGAT) activity remained almost unchanged. Sedaxane also improved leaf phenylalanine ammonia-lyase (PAL) activity, which may be responsible for the increase in shoot antioxidant activity (phenolic acids), mainly represented by p-coumaric and caffeic acids. We conclude that, in addition to its protective effect, sedaxane can facilitate root establishment and intensify nitrogen and phenylpropanoid metabolism in young maize plants, and may be beneficial in overcoming biotic and abiotic stresses in early growth stages

Effects of field inoculation with VAM and bacteria consortia on root growth and nutrients uptake in common wheat

This study investigated the effects of a commercial biofertilizer containing the mycorrhizal fungus Rhizophagus irregularis and the diazotrophic N-fixing bacterium Azotobacter vinelandii on root and shoot growth, yield, and nutrient uptake in common wheat (Triticum aestivum L.) in order to improve the sustainable cultivation of this widespread crop. The trials were carried out in controlled conditions (rhizoboxes) and in open fields over two years to investigate the interaction between inoculation and three doses of nitrogen fertilization (160, 120 and 80 kg ha1) in a silty-loam soil of the Po Plain (NE Italy). In rhizoboxes, efficient root colonization by R. irregularis was observed at 50 days after sowing with seed inoculation, together with improved root tip density and branching (+~30% vs. controls), while the effects of post-emergence inoculation by soil and foliar spraying were not observable at plant sampling. In the open, field spraying at end tillering significantly increased the volumetric root length density (RLD, +22% vs. controls) and root area density (+18%) after about two months (flowering stage) in both years under medium and high N fertilization doses, but not at the lowest N dose. In absence of inoculation, RLD progressively decreased with increased N doses. Inoculation had a negligible effect on grain yield and N uptake, which followed a typical N dose-response model, while straw Zn, P, and K concentrations were seldom improved. It is concluded that medium-high N fertilization doses are required to achieve the target yield and standards of quality (protein contents) in wheat cultivation, while the use of this mixed VAM-PGPR biofertilizer appears to be a sustainable mean for minimizing the adverse effects of chemical N fertilizers on root expansion and for improving the uptake of low-mobility nutrients, which has potentially relevant environmental benefits

Potential of avifauna as a conservation tool for the Ivaí River Biodiversity Corridor / Potencial da avifauna como ferramenta de conservação do Corredor da Biodiversidade do Rio Ivaí

Os corredores ecológicos são instrumentos de gestão ambiental e territorial que visam conectar fragmentos de áreas naturais, permitindo o fluxo de genes e o movimento da biota, contribuindo para a distribuição de espécies e colonização de áreas degradadas. No Estado do Paraná, o ecossistema predominante é a Mata Atlântica, que apresenta valor ecológico comparável à Floresta Amazônica. Apesar de abrigarem uma fauna e flora ricas em espécies, a Mata Atlântica não teve a mesma atenção dedicada à Amazônia em relação à Amazônia, e a falta de ações de conservação é suprimida em cerca de 5% de sua cobertura original, que é organizada em fragmentos esparsos e desconectados. Apesar da criação do Corredor da Biodiversidade do Rio Ivaí, ainda há resistência na manutenção de áreas preservadas, principalmente por pequenos proprietários, uma vez que seriam inúteis para o plantio. Embora ainda exista uma grande diversidade de espécies animais nessa região, tornou-se necessário apresentar uma alternativa hábil para promover e valorizar a região, seu uso sustentável e desenvolvimento econômico. Nesse contexto, e considerando a importância de promover a educação ambiental com atividades de baixo impacto, a principal preocupação deste trabalho foi a disseminação da Observação de Aves, considerada um segmento do ecoturismo, que além de atuar como alternativa ao desenvolvimento econômico e sustentável, é capaz de promover a responsabilidade social e ambiental na região

Fontes de fósforo mineral e organomineral no estado nutricional e no crescimento inicial da cana-de-açúcar / Sources of mineral and organomineral phosphate in the nutrition status and initial growth of sugarcane

Avaliou-se os efeitos da adubação organomineral comparado ao mineral fosfatada no desenvolvimento inicial da cana-de-açúcar em casa de vegetação no Centro de Cana do IAC, em Ribeirão Preto - SP.  O ensaio foi conduzido em Delineamento Inteiramente Casualizado, em esquema fatorial 5x2, com 5 dose de P2O5 (20, 40, 80, 160 e 320 mg.dm-3) e duas fontes (mineral e organomineral), em 4 repetições. Foram utilizados vasos plásticos preenchidos com 20 kg de solo com baixo teor de P disponível. Tanto a fonte organomineral como a fonte mineral proporcionaram desenvolvimento inicial similar para a altura de plantas aos 150 dias após plantio, peso fresco e seco de raiz e parte aérea e número de perfilhos. As doses de 160 e 320 mg.dm-3 de P2O5, promoveram maior peso fresco e peso seco da parte aérea e a dose de  320 mg.dm-3 de P2O5 maior número de perfilhos aos 150 dias após plantio

Reconstruction of the late quaternary glacial geology on King George Island, South Shetland Islands: First steps of a geoscientific project

King George Island (Isla 25 de Mayo) is the largest one of the South Shetland Islands (SShI). This archipelago is located approximately 120 km NW of the Antarctic Peninsula, from which it is separated by the Bransfield Strait (Mar de la Flota). The SShI are located just south of the Antarctic Convergence Zone in a key location for investigating glacial and climatic fluctuations relative to both the Southern Hemisphere and the rest of Antarctica. The geomorphology and glacier geology of the SShI (Sugden and John 1973, Hall 2003 and 2007, Del Valle et al. 2007, Strelin 2010, Simms et al. 2011) constitutes a fragmentary record. Despite the deglaciation, inland ice free areas are scarce and are strongly affected by the thaw with the consequent destruction of previous geoforms. The few obtained radiocarbon ages on land exposures have poor stratigraphic control being necessary to consider the problems of pollution and the reservoir effect that affect them. Based on geochemical and sedimentological proxies and radiocarbon dating in sedimentary cores obtained from bays, some glaciers advances and warm periods have been inferred for the middle and late Holocene, among them are those corresponding to the Medieval Climate Optimum and the Little Ice Age (LIA) (Yoon et al. 2000 and 2004, Hass et al. 2010, Monien et al. 2011). It should be noted that for some glaciological reconstructions based on organic radiocarbon dating on marine sediments the ages are still questionable. Often it does not exist yet a clear criteria of correlation that allow to link between glaciterrestrial sediments and glacimarine ones. The study of the glacial, periglacial and coastal marine record of King George Island has a particular importance to enhance the knowledge of its paleoenvironmental evolution since the Marine Isotopic Stage 3 (MIS 3). There is no precision on the beginning and end of the Last Glacial Maximum (LGM), nor on the rhythm of the deglaciation post-LGM, known as Termination 1, both for coastal and marine areas, as well as offshore areas from King George Island. In the same way, it´s not known if there was a glacial advance linked with the Antarctic Cold Reversal clearly detectable in Antarctic ice cores or sediment deposits in southern Patagonian exposures (Strelin et al. this congress). The way in which the deglaciation continued during the early Holocene, the peak of the Holocene marine transgression (Strelin et al. this Congress), the later chronology of the Neoglacial advances, including the LIA, and the warmer periods that separate them are as well topics to deepen. The objective of this project is to study and date the geomorphological and glaciterrestrial evidences linked to the glacial history in the area of South Shetland Islands, since MIS 3, correlate them with bathymetric records and proxies from marine cores and discuss its link with other sectors of the Antarctic Peninsula, particularly with James Ross Islan