Os Sistemas Apícolas e a Agricultura Familiar: um estudo de caso sobre a Cooperativa de Apicultores de Canguçu (COOMELCA), município de Canguçu, RS.

Dissertação (Mestrado) - Programa de Pós-Graduação em Sistemas de Produção Agrícola Familiar. Faculdade de Agronomia Eliseu Maciel. Universidade Federal de Pelotas, Pelotas, 2017. Orientador: Antônio Jorge Amaral Bezerra, Co-orientador: Luis Fernando Wolff, CPACT

Design, Implementation and Evaluation of PsyWeb, a Learning Environment in a Problem Based Learning Curriculum.

In this article we describe the design and implementation of PsyWeb, a rich learning environment for the new problem based study in Psychology at Erasmus University Rotterdam Experiences are reported for the first five (of eight) courses of the first year of the new study. Students opinions have been collected as part of a survey at the end of each course. Results indicate that students are positive about PsyWeb. The overall appreciation shows a slight increase over time. Starting with the second course, usage of PsyWeb has been logged. Usage has been quantified in terms of the number of unique IP-addresses per day. Using this measure we assume that PsyWeb has a student reach between 25% and 100% per day. Usage shows a slight increase over the courses. The implementation of a series of additions to PsyWeb has been planned for the next year

Random tree growth by vertex splitting

We study a model of growing planar tree graphs where in each time step we separate the tree into two components by splitting a vertex and then connect the two pieces by inserting a new link between the daughter vertices. This model generalises the preferential attachment model and Ford's $\alpha$-model for phylogenetic trees. We develop a mean field theory for the vertex degree distribution, prove that the mean field theory is exact in some special cases and check that it agrees with numerical simulations in general. We calculate various correlation functions and show that the intrinsic Hausdorff dimension can vary from one to infinity, depending on the parameters of the model.Comment: 47 page

Storage of correlated patterns in a perceptron

We calculate the storage capacity of a perceptron for correlated gaussian patterns. We find that the storage capacity $\alpha_c$ can be less than 2 if similar patterns are mapped onto different outputs and vice versa. As long as the patterns are in general position we obtain, in contrast to previous works, that $\alpha_c \geq 1$ in agreement with Cover's theorem. Numerical simulations confirm the results.Comment: 9 pages LaTeX ioplppt style, figures included using eps

Fijnstofemissie uit stallen: (groot)ouderdieren van vleeskuikens = Dust emission from animal houses: broiler breeders

In this study emissions of fine dust (PM10 and PM2.5) from houses for broiler breeders were determined. In addition, emissions of ammonia, greenhouse gases and odour were determine

Herschel Survey of Galactic OH+, H2O+, and H3O+: Probing the Molecular Hydrogen Fraction and Cosmic-Ray Ionization Rate

In diffuse interstellar clouds the chemistry that leads to the formation of the oxygen bearing ions OH+, H2O+, and H3O+ begins with the ionization of atomic hydrogen by cosmic rays, and continues through subsequent hydrogen abstraction reactions involving H2. Given these reaction pathways, the observed abundances of these molecules are useful in constraining both the total cosmic-ray ionization rate of atomic hydrogen (zeta_H) and molecular hydrogen fraction, f(H2). We present observations targeting transitions of OH+, H2O+, and H3O+ made with the Herschel Space Observatory along 20 Galactic sight lines toward bright submillimeter continuum sources. Both OH+ and H2O+ are detected in absorption in multiple velocity components along every sight line, but H3O+ is only detected along 7 sight lines. From the molecular abundances we compute f(H2) in multiple distinct components along each line of sight, and find a Gaussian distribution with mean and standard deviation 0.042+-0.018. This confirms previous findings that OH+ and H2O+ primarily reside in gas with low H2 fractions. We also infer zeta_H throughout our sample, and find a log-normal distribution with mean log(zeta_H)=-15.75, (zeta_H=1.78x10^-16 s^-1), and standard deviation 0.29 for gas within the Galactic disk, but outside of the Galactic center. This is in good agreement with the mean and distribution of cosmic-ray ionization rates previously inferred from H3+ observations. Ionization rates in the Galactic center tend to be 10--100 times larger than found in the Galactic disk, also in accord with prior studies.Comment: 76 pages, 25 figures, 6 tables; accepted for publication in Ap