Study of ground state properties of halo nuclei via quasi-free scattering reactions

The main goal of this work was the analysis and interpretation of experimental data obtained for the reaction (p,pn) of the one neutron halo nucleus 15C on a proton target. The measurement, performed at the GSI laboratory, was part of an experimental campaign (Experiment S393) of the R3B collaboration and the first step towards the measurement of fully exclusive reaction cross sections on exotic nuclei. The so-called halo nuclei are of high interest as they consist of bound nuclei characterized by one or more valence nucleons orbiting at larger distances from a core. These are novel quantum systems appearing at the limits of the dripline. Furthermore, halo nuclei are characterized by low separation energies, resulting in very narrow momentum distributions of the core in nucleon knockout reactions at relativistic energies. One neutron-halo nucleus of particularly high interest is 15C, which has a neutron separation energy of Sn = 1.218 MeV. Ground state and spectroscopic information have been extracted experimentally from Coulomb dissociation studies resulting in a consistent picture with a dominant (14C(0+) x 2s1/2) configuration. Momentum distributions of the core extracted from single neutron knockout reactions exhibited a width of 67 MeV/c, consistent with larger separation energy and the same dominant configuration. However, calculations failed to reproduce the tail of the measured momentum distributions. The momentum distributions are inclusive measurements and thus it is desirable to measure exclusive observables which incorporate more physics information. The Faddeev/AGS formalism is a non-relativistic three-body multiple scattering framework that treats equally all opening channels (elastic, breakup and transfer) and has been used to assess the validity of approximations considered in traditional scattering frameworks. This has highlighted that traditional reaction approaches may not be adequate to study the nuclei under consideration. It was also successfully applied to the study of reactions involving halo nuclei as well as light/medium nuclear systems. The 15C case, due to its dominant ground state configuration of 14C core in its ground state and a s-wave valence neutron (14C(0+) x 2s1/2), constitutes a very suitable case to apply the Fadeev/AGS reaction formalism to the study of the 15C

A EDUCAÇÃO AMBIENTAL COMO FERRAMENTA DO AGRONEGÓCIO PARA DIVULGAREM SUAS ATIVIDADES NO CONESUL

O artigo argumenta sobre a importância de se fazer uma reflexão sobre a educação ambiental desenvolvida pelas empresas e entidades representativas do agronegócio, uma vez que é necessário, considerar os objetivos das mesmas como sendo de interesse em divulgarem uma imagem de empresa sustentável, geradora de emprego, renda e de comprometimento com as questões sociais. No entanto, a histórica desigualdade na propriedade da terra no Conesul, imprime em seus conflitos indicadores negativos na distribuição de renda, riqueza. Diante do exposto, entende-se que deve estar inserido nos debates um viés crítico e transformador. Sendo assim, sustentamos teoricamente o assunto sobre o tema para que sirva de apoio aos dados empíricos de uma tese de doutorado

Avaliação in vitro da atividade de seis drogas antimicrobianas contra Neisseria gonorrhoeae

Use of antimicrobials for the treatment of gonorrhea started in 1930 with the utilization of sulfonamides. With the years other drugs were used for its treatment such as penicillin, tetracycline, spectinomycin, and others. Although highly specific in the beginning, these drugs, with time did not show anymore the expected therapeutic results because of aspects of chromosomal and plasmid-mediated resistance. The purpose of this study was to evaluate the susceptibility of Neisseria gonorrhoeae strains to six drugs used for its treatment (penicillin, tetracycline, cefoxitin, thiamphenicol, spectinomycin and ofloxacin) by the determination of minimal inhibitory concentrations of these drugs. We concluded that drugs, such as cefoxitin, thiamphenicol and spectinomycin still are excellent pharmacological agents for the treatment of gonorrhea. Penicillin, although still efficient, needs more attention regarding its use, as well as ofloxacin, because of the emergence of resistant strains. Tetracycline and its derivatives should be strongly contraindicated for the treatment of gonorrhea.A utilização de antimicrobianos no tratamento da gonorréia iniciou-se em 1930 com a utilização das sulfonamidas. No decorrer dos anos outras drogas passaram a ser utilizadas em seu tratamento como a penicilina, tetraciclina, espectinomicina e outras. Embora altamente eficazes no início, essas drogas, ao longo do tempo, passaram a não mais apresentar o resultado terapêutico esperado em virtude do aparecimento de quadros de resistência cromossômica e plasmidial. Este trabalho teve por objetivo avaliar a sensibilidade de cepas de Neisseria gonorrhoeae a seis drogas utilizadas no seu tratamento (penicilina, tetraciclina, cefoxitina, tianfenicol, espectinomicina e ofloxacina) através da concentração inibitória mínima. Concluimos que drogas como a cefoxitina, o tianfenicol e a espectinomicina ainda constituem excelentes fármacos para o tratamento da gonorréia. A penicilina, embora ainda eficaz, enseja maiores cuidados na sua utilização, assim como a ofloxacina, frente ao surgimento de cepas resistentes e, a tetraciclina e seus derivados deve ser sobremaneira contra-indicada no tratamento da gonorréia

Towards a natural classification : the taxonomy and evolution of Xanthorrhoea

The ability to increase the filler content of paper without significantly sacrificing its mechanical strength is of high interest for papermakers. In this work, three samples of ground calcium carbonate (GCC), differing in size and in brightness, modified with silica via the sol-gel method, were used as fillers in papermaking. Handsheets were produced using a eucalyptus kraft pulp furnish and with a filler amount near 20%. It was found that not only were the strength properties of the handsheets produced with the modified GCCs always significantly better than those obtained with the unmodified GCCs (e.g., the tensile index exhibited improvements of 16 to 20%), but bulk also was increased (by 7 to 13%). Some decreases in the light scattering and opacity values were noted when using the modified GCC, but the brightness was roughly the same. The enhanced fiber-to-filler bonding may be attributed to the hydrogen bonding between the cellulosic fibers and the hydroxyl groups of the silica coating the calcium carbonate particles

Nutrient recovery from swine waste and protein biomass production using duckweed ponds (Landoltia punctata): Southern Brazil

Artigo publicado em: IWA - Water Sciencie et TechnologyBrazil is one of the most important countries in pork production worldwide, ranking third. This activity has an important role in the national economic scenario. However, the fast growth of this activity has caused major environmental impacts, especially in developing countries. The large amount of nitrogen and phosphorus compounds found in pig manure has caused ecological imbalances, with eutrophication of major river basins in the producing regions. Moreover, much of the pig production in developing countries occurs on small farms, and therefore causes diffuse pollution. Therefore, duckweed pond have been successfully used in the swine waste polishing, generating further a biomass with high protein content. The present study evaluated the efficiency of two full scale duckweed ponds for the polishing of a small pig farm effluent, biomass yield and crude protein (CP) content. Duckweed pond series received the effluent from a biodigester-storage pond, with a flow rate of 1 m3/day (chemical oxygen demand rate ¼ 186 kg/ha day) produced by 300 animals. After 1 year a great improvement of effluent quality was observed, with removal of 96% of total Kjeldahl nitrogen (TKN) and 89% of total phosphorus (TP), on average. Nitrogen removal rate is one of the highest ever found (4.4 g TKN/m2 day). Also, the dissolved oxygen rose from 0.0 to 3.0 mg/L. The two ponds produced together over 13 tons of fresh biomass (90.5% moisture), with 35% of CP content, which represents a productivity of 24 tonsCP/ha year. Due to the high rate of nutrient removal, and also the high protein biomass production, duckweed ponds revealed, under the presented conditions, a great potential for the polishing and valorization of swine waste. Nevertheless, this technology should be better exploited to improve the sustainability of small pig farms in order to minimize the impacts of this activity on the environment