Amphibian populations worldwide are currently in decline. One approach to preventing extinction of some of the affected species is to create assurance colonies. These sustainable captive populations might some day be used to reestablish wild populations. One issue with creating assurance colonies is successful breeding; often difficulties arise when attempting to breed exotic animals in captivity. Sexual conditioning, a form of Pavlovian conditioning, has been shown to improve breeding behavior. In this project the efficacy of sexual conditioning to improve breeding behavior in the dyeing dart frog (Dendrobates tinctorius) was tested. The frogs were trained with a stimulus that was either predictive of or independent of exposure to a member of the opposite sex. The group trained with the predictive stimulus showed shorter latencies to a variety of breeding behaviors and produced more eggs than the control groups. The sexual conditioning procedure also increased expression of various breeding behaviors allowing for careful examination of calls and visual signaling within this species.

Yes / Several contributions in answering granulation challenges including the use of computer simulation and well thought out experimental analyses are being researched. Using a twin screw granulator (TSG) by design of experiments (DoE), comparisons on 1) equipment similarities i.e., continuous and 2) shear forces, are made to previous literature on continuous equipment and a Cyclomix. This study proposes that equipment specific DoE, better explains the contribution of parameters than investigating an identified parameter from the experimental findings from a specific equipment. Granule strength and structure are presented together with the contribution of process parameters, speed, temperature, and binder content. Seeded structures are present in all but the Extrudomix. Longer residence times within the Cyclomix facilitates seeded structures. Granule crushing strengths are higher in TSG than all other continuous equipment. Optimum condition for the formation of stronger granules with least variation is around 65.4 °C. / The authors would like to acknowledge the support from the CCIP grant (Collaboration, Capacity and IP Development) fund from the University of Bradford for ordering cunsumables and equipment.

[pt] O liner é um elemento de extrema importância no processo construtivo de um aterro sanitário, pois funciona como uma barreira capaz de impedir a percolação de agentes contaminantes através do subsolo. Os liners ou camadas impermeabilizantes são geralmente construídos a partir de materiais que possuem baixa permeabilidade. A escolha de um material adequado, assim como o controle dos processos construtivos são indispensáveis para garantir um bom desempenho da camada impermeabilizante. O processo de compactação é de extrema importância neste tipo de obra geotécnica. Os ensaios de compactação realizados em laboratório têm como objetivo reproduzir as condições de campo, no entanto, em numerosos casos há diferenças importantes entre os mecanismos de compactação utilizados, na preparação do material antes do processo de densificação e nas características das amostras, o que gera como conseqüência discrepâncias nos valores de permeabilidade de campo com os de laboratório. O objetivo principal do presente estudo é avaliar experimentalmente a influência de dois mecanismos diferentes de compactação (dinâmico, com o Proctor Normal e estático, com o método de compactação por pisoteamento) nos valores de permeabilidade de um solo coluvionar e de um composto orgânico para seu eventual uso em um liner. Os ensaios foram realizados em corpos de prova com diferentes teores de umidade, preparados com solo coletado no campo Experimental II da PUC-Rio, com composto orgânico produzido a partir do processo de compostagem da grama do Aeroporto Internacional Galeão (RJ), e com misturas em diferentes proporções de ambos os materiais. / [en] The liner is one of the most important elements in a sanitary landfill project, since it works as a barrier capable to impede seepage of pollutant substances through the subsurface. This element is usually built with materials that have low permeability. The choice of the right material as well as the control and supervision of the constructive processes are fundamental to achieve a good liner performance. The compaction process is extremely important in this type of geotechnical impoundment. Laboratory compaction intends to reproduce the field conditions; however, in some cases, there happen to be important differences between the compaction mechanisms used, the preparation of the material before the densification process and the specimens characteristics, which cause discrepancies between the permeability values obtained in the field and the ones obtained in the laboratory. The main objective of this study is to evaluate experimentally the effect of two different compaction mechanisms (dynamic, with standard Proctor and static, with the kneading compaction method) in the hydraulic conductivity of a colluvionar soil and an organic compound for their eventual use in a liner. The tests were executed using specimens with different water contents, prepared with colluvionar soil extracted from the Experimental Field II at the PUC-Rio, with the organic compound, and with mixtures of both materials in different proportions.

Asphalt mixture compaction is an important procedure of asphalt mixture construction and can significantly affect the performance of asphalt pavement. Many laboratory compaction methods (or devices), have been developed to study the asphalt mixture compaction. Nevertheless, the whole process from the selection of aggregate to laboratory compaction is still time-consuming and requires significant human and material resources. In order to better understand asphalt mixture compaction, some researchers began to use finite element method (FEM) to study and analyze mixture compaction. However, FEM is a continuum approach and lacks the ability to take into account the slippage and interlocking of aggregates during compaction. Discrete Element Method (DEM) is a discontinuum analysis method, which can simulate the deformation process of joint systems or discrete particle assembly under quasi-static and dynamic condition. Therefore, it can overcome the shortcomings of FEM and is a more effective tool than FEM to simulate asphalt mixture compaction. In this study, an open source 3D DEM code implemented with the C++ programming language was modified and applied to simulate the compaction of hot-mix asphalt (HMA). A viscoelastic contact model was developed in the DEM code and was verified through comparison with well established analytical solutions. The input parameters of the newly developed contact model were obtained through nonlinear regression analysis of dynamic modulus test results. Two commonly used compaction methods (Superpave gyratory compaction and asphalt vibratory compaction) and one linear kneading compaction based on APA machine were simulated using the DEM code, and the DEM compaction models were verified through the comparison between the DEM predicted results and the laboratory measured test results. The air voids distribution within the asphalt specimens was also analyzed by post processing virtual DEM compaction digital specimens and the level of heterogeneity of the air void distribution within the specimens in the vertical and lateral directions was studied. The DEM simulation results in this study were in a relatively good agreement with the experimental data and previous research results, which demonstrates that the DEM is a feasible method to simulate asphalt mixture compaction under different loading conditions and, with further research, it could be a potentially helpful tool for asphalt mix design by reducing the number of physical compactions in the laboratory.