RESUMO Uma formulação recentemente desenvolvida para o problema de difusão anômala, a qual emprega um termo diferencial de quarta ordem, apresentou em determinadas situações observadas na literatura valores fisicamente irreais em sua solução. Neste trabalho é realizado um estudo do efeito coeficiente de difusão secundária visando contribuir para o entendimento do comportamento das soluções nessas situações. É implementada uma função para representar a variação da parcela sujeita a difusão primária e secundária, de acordo com a quantidade da propriedade em difusão. É apresentada a formulação para a solução desse novo modelo pelo Método de Diferenças Finitas. Os resultados obtidos são compatíveis com aqueles apresentados em trabalhos anteriores na literatura.

ABSTRACT A recent formulation for anomalous diffusion problems, which envolves a fourth-order differential term, has presented negative values in its solution for certain cases. This paper presents a study of the effect of secondary diffusion coefficient in order to contribute with the understanding of the solutions behavior in these situations. A function was implemented to represent the variation in the parcel subject to primary and secondary diffusion, according to the amount of the property in diffusion. The formulation for the solution of this new model by the Finite Difference Method is presented. The results obtained are compatible with those presented in previous works in the literature.

RESUMO Este artigo apresenta a metodologia para a solução de um problema de advecção e difusão bimodal unidimensional utilizando o Método de Diferenças Finitas. Além do termo de transporte advectivo e da difusão primária (que corresponde ao fluxo de Fick), a equação da difusão bimodal inclui um termo relativo à um fluxo secundário que é modelado por um termo diferencial de quarta ordem. O problema foi analisado para diferentes condições iniciais e de contorno, sendo os resultados compatíveis com os apresentados em trabalhos anteriores da literatura.

ABSTRACT This paper presents a methodology for the solution of a bimodal advection and diffusion problem using the Finite Differences Method. In addition to the advective transport term and primary diffusion (which corresponds to the Fick’s flux), the bimodal diffusion equation includes a term relative to a secondary flow that is modeled by a fourth order differential term. The problem was analyzed for different initial and boundary conditions and the results are compatible with those presented in previous studies in the literature.

Phloea subquadrata and Phloeophana longirostris are subsocial species that differ from each other in their host plants and degrees of aggregation. Until recently, only ten low-molecular weight compounds, a sesquiterpene, and dimers of (E)-4-oxo-2-hexenal had been reported from the contents of P. subquadrata glands. Here, the main goal was to distinguish the volatile compounds released by adult males, adult females and nymphs of the two species. The analyses revealed 103 compounds, of which 44 were exclusive to Phloeophana longirostris and 15 were exclusive to Phloea subquadrata. The data were analyzed by chemometric methods, which discriminated the phloeid species by developmental stage and sex. (E)-2-Hexenal, (E)-4-oxo-2-hexenal and (E)-2-octenal were found in both species. Adult individuals were characterized by the presence of methyl 2-methylbutanoate, (E)-2-hexenyl acetate and 2-hexenyl butanoate, and nymphs were characterized by 5-ethyl-2(3H)-furanone and (E)-2-octenal. There was chemical distinction between volatiles of adults and nymphs of the two species studied.

Bark bugs belonging to the family Phloeidae are known for their camouflage on tree trunks. The nymphs store in dorsal abdominal glands defensive secretions with a pungent odor mainly constituted of (E)-2-hexenal, (E)-2-octenal, and (E)-4-oxo-2-hexenal. The metathoracic glands of adults (male and female) store (E)-2-hexen-1-ol and (E)-2-hexenyl acetate, which are less irritating than their corresponding aldehydes. Additional compounds of m/z 224 were detected in the scent glands of these insects and were previously suggested to be dimers of the (E)-4-oxo-2-hexenal. Thus, the aim of this study was to elucidate the details of the chemical structure of the dimers found in the scent glands of Phloea subquadrata. These dimers were obtained by synthesis and were compared with the natural products, confirming the dimeric structures of the latter. These (E)-4-oxo-2-hexenal dimeric compounds are novel and have not been reported before.

Resumo Aves frugívoras são importantes dispersoras de sementes e influenciam no recrutamento de muitas espécies na floresta tropical. A eficiência dessa dispersão geralmente depende da qualidade do meio ambiente, das espécies de aves envolvidas, da riqueza e diversidade de recursos e de baixos níveis de impactos antrópicos. Neste estudo nós comparamos o número de avistamentos de jacuguaçus (Penelope obscura) por Km e seus movimentos em duas áreas na Serra do Japí, uma no entorno da base administrativa (Base) onde as aves receberam alimentos antropogênicos e outra em área pristina (DAE) sem fornecimento de alimentos humanos. Também comparamos a riqueza de sementes nativas nas fezes das aves que vivem nestas duas áreas. Embora a abundância de P. obscura tenha sido maior na Base, esses indivíduos deslocaram-se menos, dispersaram 80% menos espécies de plantas e consumiram 30% menos sementes do que os indivíduos do DAE. A rarefação indicou uma baixa riqueza na dieta frugívora das aves da Base quando comparada às populações do DAE. Concluímos que o fornecimento de alimentos humanos pode interferir no comportamento dessas aves e na riqueza de espécies de sementes nativas dispersadas.

Abstract Frugivorous birds are important seed dispersers and influence the recruitment of many plant species in the rainforest. The efficiency of this dispersal generally depends on environment quality, bird species, richness and diversity of resources, and low levels of anthropogenic disturbance. In this study, we compared the sighting number of dusky-legged guans (Penelope obscura) by km and their movement in two areas of Serra do Japi, one around the administrative base (Base) where birds received anthropogenic food and a pristine area (DAE) with no anthropogenic resource. We also compared the richness of native seeds in feces of birds living in these two areas. Although the abundance of P. obscura was higher in the Base, these individuals moved less, dispersed 80% fewer species of plants and consumed 30% fewer seeds than individuals from DAE. The rarefaction indicated a low richness in the frugivorous diet of birds from the Base when compared to the populations from DAE. We conclude that human food supply can interfere in the behavior of these birds and in the richness of native seeds dispersed.