During the reproductive season Blue-black grassquit (Volatinia jacarina) males are found in clusters, wherein they exhibit a distinctive display that consists of repeated, vertical leaps while simultaneously producing a brief vocalization. The main objective of this study was to describe details of the species' reproductive behavior in a "Cerrado" area of central Brazil and compare these data with some studies carried out in other areas. The data obtained concerning different aspects of nesting, laying and hatching were generally similar to those obtained in previous studies in other areas. However, we found that the typical clutch size of two eggs per nest is lower, and egg and nestling mortality rates higher in our area than what has been reported elsewhere. Our results suggest that males differ in time expended with different activities according to their reproductive condition and also provide extensive parental care. We found that display execution rates peak in the early morning and in the late afternoon and are higher in the middle of the breeding season. We also found that there is an inverse relation between the height of the display leap and the height of the perch. Reprodução do tiziu no Brasil central Resumo Durante a estação reprodutiva, machos de tiziu (Volatinia jacarina) são encontrados agregados e apresentam uma exi-bição bastante conspícua, que consiste de saltos verticais associados a uma curta vocalização. Através de observações realizadas em uma área de Cerrado na região do Brasil central, este trabalho teve como objetivos detalhar alguns as-pectos da biologia reprodutiva de V. jacarina e comparar tais dados com os poucos trabalhos existentes sobre a espécie. Os dados obtidos neste estudo com relação aos diferentes aspectos da nidificação, postura e eclosão dos ovos se mos-traram semelhantes, em geral, àqueles encontrados em estudos anteriores, diferindo apenas com relação ao número de ovos por ninho (a maioria dos ninhos com apenas dois ovos) e às taxas de predação, que se mostraram mais elevadas. Os dados mostram ainda que machos variam com relação ao gasto de tempo com diferentes atividades de acordo com a condição reprodutiva e que os mesmos investem parentalmente. Foram encontradas ainda, que as taxas de execução de exibição são mais elevadas no início da manhã e no final da tarde, assim como também tem um pico no meio da estação reprodutiva. Encontramos também uma relação inversa entre a altura do salto da exibição e a altura do poleiro.

Blue-black Grassquits (Volatinia jacarina) are small, granivorous, Neotropical birds that are abundant in central Brazil. During the reproductive season, the socially monogamous males acquire a blue-black plumage and defend very small, clustered territories that resemble leks. They execute a conspicuous courtship display that consists of a leap, revealing white under-wing patches, synchronized with a vocalization. We collected data on the morphology and behavior of banded males and characteristics of their territories to determine how these factors may influence acquisition of mates and nesting. For a second group of birds in the area, we used microsatellite genotyping to test the breeding synchrony hypothesis, which predicts that tropical species that breed synchronously should exhibit high rates of extra-pair fertilization (EPF). We found that males that successfully formed a pair bond differed from unsuccessful males in their behavior, but not in morphological attributes or territory features. Successful males spent more time in their territories, executed displays for longer periods and at greater rates, and their display leaps were higher. These results point to the greater importance of behavior relative to other factors in the successful reproduction of Blue-black Grassquit males. In the second group of birds, EPFs occurred in 63% of 11 nests and involved 50% of the 20 chicks sampled. This exceptionally high incidence of EPF in the small sample analyzed occurred in diverse contexts, including intraspecific parasitism and quasi-parasitism, a rare type of maternity loss where the resident female is parasitized by other females that were fertilized by the resident male. A short and highly synchronized breeding season, clustered breeding in small territories, and granivorous habits may contribute to the high rates of EPF in this tropical species.

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This work presents a novel numerical scheme for the acceleration of the 2-D Transmission-Line Matrix method. The idea is the use of contmlled leaps in the lime step in order to achieve faster processing. The leaps are numerically stable and may result in significant CPU savings. In addition to the adjustable time step, the procedure becomes more efficient by using model reduction with Schur decomposition. The technique was validated by the calculation of a microwave filter and subsequent comparison to the normal TLM results.Index Terms -CAD tools, Numerical Techniques, ModelReduction. IN~RODIICTIONThe TLM method (Transmission-Line Matrix) is a numerical technique applied to the general solution of the Maxwell equations. The problem is usually solved in the time domain using transmission line network analogies. Thc method can solve complcx and arbitrary shaped problems. However, TLM is also hound hy the same limitations of other numerical techniques. For instance, if one uses TLM to perform a n electromagnetic analysis of microelectronic circuits, the method will show several drawbacks. In this particular case, due to the relationship of the spatial and temporal discretization, a TLM analysis of an integrated circuit system demands large amounts of memoq. Moreover, the solution will require several millions of time steps. As a result, a full electromagnetic simulation of such a system is often impractical. This work presents an improvement in the TLM method to overcome the problems shown above. The authors of this article would like to suggest the name Johns Super Node (TLM-JSN) for the technique. This is a tribute to the creator of this method, P. B. Johns et al. [I]. The new formulation allows significant CPU savings for simulations. The theory describing TLM-JSN and the model reduction technique (ROW arc shown in the next section. The final section shows some examples that are compared to [2]-[31. 11. THEORY The electromagnetic waves in the TLM method propagate through a mesh of transmission lines interconnected at the nodes [4]. This process is described as a function of an incident and reflected vologe waves, v' and V', respectively at the nodes. As demonstrated in [21, the algorithm may he expressed by the interactive resolution of: [VI; =[SI. [VI. Where [SI is the scattering matrix that refers to the mesh nodes, and [C] is the connection matrix that describes the network's topology. In (1) and (2). k and kcl indicate the discretized time step in which the incident and reflected voltages are calculated. The TLM-JSN uses a state equation formulation to relate the incident and the reflected voltages. In the JSN method, the problem is divided into outer and inner domains. The solution is based on the calculation of the extemal reflected voltage in the outer domain ,V'caused by the incident voltages in the inner domain ,nv' and the incident voltages from the extemal domain_V'. Therefore, ( I ) and (2) are formulated as an interactive sequence:(4)Where [SI and [C] are the same matrices as in (I) and(2). [TI is t...