Avaliação da qualidade de calcários agrícolas através do PRNT

Agricultural limestones of various PRNT (Relative Power of Total Neutralization) values, calculated considering the relative efficiency of their granulometric fractions, were used in a comparative study. A number of 22 limestone samples were collected ; 12 from different mills from the municipalities of Rio Claro, Piracicaba and Tietê and 10 selected to obtain a desired range of granulometric and chemical composition in the lot. The results indicate that PRNT formulas currently used in Brazil may be underestimating limestone efficiency. The proposed new formula can be taken as a more reliable index for agricultural purposes.Foram comparados os valores do PRNT de calcários agrícolas, empregando fórmulas que se baseiam em diferentes valores de eficiência relativa das frações granulométricas que compõem esses materiais. Foram utilizadas 22 amostras de calcários, sendo 12 de Rio Claro, Piracicaba e Tietê, Estado de São Paulo e as demais especialmente escolhidas visando variação nas composições granulométrica e química. Os resultados sugerem que as fórmulas de PRNT que têm sido utilizadas no Brasil , devem estar substimando a eficiência desses produtos , além de carecerem de um respaldo experimental mais convincente. A nova fórmula proposta pode ser mais confiável, apesar de estar também sujeita a várias críticas

Eficiência relativa de diferentes frações granulometricas de calcários na neutralização da acidez dos solos, avaliada em laboratório

Two sedimentar and two metamorphic limestone, separated in the sieves n°s (ABNT) 5-10, 10-30, 30-50, and 50-60 were incubated with three types of soils. The neutralizing efficiency was evaluated by pH variation. The results showed that their efficiency is independent of the geological nature of limestone but is dependent of soil type. The following efficiency value is suggested for each size fraction: larges than size 10 is 0%, size 10-30 is 35%, sizes 30-50 is 75% and smaller than size 50 is 100%.As frações granulométricas retidas nas peneiras n°s (ABNT) 5-10, 10-30, 30-50, e 50-60 de quatro calcários, sendo dois sedimentares e dois metamórficos, foram incubadas durante 160 dias com três tipos de solos, em condições de laboratório. A eficiência das frações na neutralização da acidez dos solos foi avaliada pela variação do pH. Os resultados permitiram concluir que a referida eficiência independe da natureza geológica do calcário mas depende do tipo de solo, sendo decrescente na seguinte ordem: LVd, LEd e LEm. Apesar da legislação atual normatizar as características físicas dos calcários, bem como os seus graus de eficiência, a presente pesquisa sugere novos valores para a eficiência relativa das diferentes frações granulometricas de calcários: fração maior do que 10:0%, de 30:35%; de 30-50:75% e menor que 50:100%

Las garrapatas de Uruguay : especies, hospedadores, distribución e importancia sanitaria

Se presenta una actualización de las especies de garrapatas de Uruguay. La lista comprende 31 especies que se clasificaron en las siguientes categorías: residentes (15 especies); probablemente residentes (3 especies); accidentales (1 especie); a confirmar (4 especies); diagnóstico erróneo (6 especies) y mención incorrecta (2 especies). Se indica la nueva posición sistemática de algunas especies, así como las sinonimias más relevantes, hospedadoras y distribución de las mismas en el país. Entre las especies de importancia sanitaria, Boophilus microplus continúa siendo la única especie con repercusión en la ganadería de nuestro país, en tanto que, con respecto a la salud humana, se ha detectado que Amblyomma triste es la especie de mayor importancia. Esta es la única especie incriminada en la transmisión de rickettsias al humano en Uruguay. Otras especies como Ornithodoros talaje, Ixodes pararicinus y Rhipicephalus sanguineys se identificaron como vectores potenciales de enfermedades para los animales y los humanos en Uruguay. Factores tales como el ingreso de animales portadores de microorganismos transmisibles por esas especies de garrapatas, cambios ecológicos y climáticos, y la colonización humana de ciertas áreas del país, pueden favorecer que tal riesgo potencial se transforme en real.The Iist of Uruguay tick species is actualized. The 31 Iisted specis were cIassified in the following categories: residents (15 species), probably residents (3) accidentals (1), to confirm (4), erroneous diagnosis (6), and mistaken records (2 species). The new systematic status of some species is clarified, and the more outstanding synonymies, the host and the geographical distribution within Uruguay are indicated. As regards the sanitary impact, Boophilu microplus is still the only species with economic significance to livestock whereas for human health Amblyomma triste is the most important species because is the only one involved with rickettsia's transmission in our country. Several other species, such a Ornithodoros talaje, lxodes pararicinus and Rhipicephalus sanguineus were identified as potential vector of diseases to animal and human. Factor as the introduction of transmissible microorganisms with carrier animals, ecological and climatic change and the human colonization of certain zone of the country, may occasione that this risk becomes a reality.EEA RafaelaFil: Venzal, José Manuel. Universidad de la República. CENUR Litoral Norte-Salto. Facultad de Veterinaria. Departamento de Parasitología; UruguayFil: Castro, Oscar. Universidad de la República. Facultad de Veterinaria. Departamento de Parasitología Veterinaria; UruguayFil: Cabrera, P.A. Universidad de la República. Facultad de Veterinaria. Departamento de Parasitología Veterinaria; UruguayFil: Souza, C.G. de. Universidad de la República. Facultad de Veterinaria. Departamento de Parasitología Veterinaria; UruguayFil: Guglielmone, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentin

Theory of Disordered Itinerant Ferromagnets I: Metallic Phase

A comprehensive theory for electronic transport in itinerant ferromagnets is developed. We first show that the Q-field theory used previously to describe a disordered Fermi liquid also has a saddle-point solution that describes a ferromagnet in a disordered Stoner approximation. We calculate transport coefficients and thermodynamic susceptibilities by expanding about the saddle point to Gaussian order. At this level, the theory generalizes previous RPA-type theories by including quenched disorder. We then study soft-mode effects in the ferromagnetic state in a one-loop approximation. In three-dimensions, we find that the spin waves induce a square-root frequency dependence of the conductivity, but not of the density of states, that is qualitatively the same as the usual weak-localization effect induced by the diffusive soft modes. In contrast to the weak-localization anomaly, this effect persists also at nonzero temperatures. In two-dimensions, however, the spin waves do not lead to a logarithmic frequency dependence. This explains experimental observations in thin ferromagnetic films, and it provides a basis for the construction of a simple effective field theory for the transition from a ferromagnetic metal to a ferromagnetic insulator.Comment: 15pp., REVTeX, 2 eps figs, final version as publishe

Perception of COVID-19 pandemic restrictions on dental researchers

Background/objectives: Historical evidence shows a gender-based disproportionate effect of pandemics across different populations. In 2020, the coronavirus disease 2019 (COVID-19) pandemic began spreading its devastating effects worldwide. The goal of the present study was to investigate the effect of the COVID-19 pandemic on research productivity, work-life arrangements, and mental health of dental professionals worldwide with focus on gender differences. Methods: A 38-item survey, concerning demographics, career stage, employer support, family structure, mental health, and relationships, was distributed to 7692 active members of the International Association for Dental Research. Bivariate associations between independent variables and the primary outcome variable were tested using Spearman's correlation test. A logistic regression model was used to assess the simultaneous, independent associations between each variable and researcher productivity. Results: A total of 722 responses were obtained, indicating a 9.4% response rate. Higher productivity was reported by male respondents (p = 0.021), and by those in senior career stages (p = 0.001). Institutional support was associated with higher productivity (p < 0.0001). Lower productivity was reported by younger researchers (p = 0.003). Remote work negatively affected productivity (p < 0.0001) and female respondents reported working more hours, regardless of work location (p = 0.004). Poor mental health was associated with low productivity (p < 0.0001). Conclusions: Our results showed that the COVID-19 pandemic significantly affected dental professionals’ perceived productivity and mental health around the globe. Younger individuals and women were disproportionally affected, and institutional support had a significant influence to mitigate effects of the pandemic for dental researchers