Trade and investment promotion between Asia-Pacific and Latin America: present position and future prospects

Includes bibliography

Expenditures, investment and financing for sustainable development in Trinidad and Tobago

Includes bibliography

Contrasting engineering effects of leaf-rolling caterpillars on a tropical mite community

Ecosystem engineers are organisms that change the physical structure of environments and provide habitats for other organisms. Lepidopteran caterpillars may act as ecosystem engineers by rolling leaves as shelters to complete metamorphosis. After being abandoned, these structures may provide shelter for other organisms. In this study, the influence of leaf-rolling caterpillars on tropical mite communities was reported. Expanded leaves and leaves rolled by larvae and also developed field experiments using leaves rolled manually with different shapes and sizes (i.e. different architectures) in different seasons were surveyed (dry and rainy). While the abundance and diversity of predatory mites were higher in rolled leaves, the abundance of phytophages decreased in these leaves. Species composition differed between rolled and expanded leaves. The structure of shelters affected the distribution of predatory mites, with higher abundances found on funnel-shaped leaves. Predatory mites only benefited from the rolled leaves in the dry season. This is the first study showing (i) the contrasting effects of ecosystem engineers on microarthropod communities, favouring some feeding guilds and inhibiting others; (ii) that the shape of rolled leaves has variable effects on mite communities; and (iii) that facilitation was temporally dependent, i.e. occurred only in the dry season. © 2013 The Royal Entomological Society.

Dynamics and coexistence in a system with intraguild mutualism

It is a tenet of ecological theory that two competing consumers cannot stably coexist on a single limiting resource in a homogeneous environment. Many mechanisms and processes have since been evoked and studied, empirically and theoretically, to explain species coexistence and the observed biological diversity. Facilitative interactions clearly have the potential to enhance coexistence. Yet, even though mutual facilitation between species of the same guild is widely documented empirically, the subject has received very little theoretical attention. Here, we study one form of intraguild mutualism in the simplest possibly community module of one resource and two consumers. We incorporate mutualism as enhanced consumption in the presence of the other consumers. We find that intraguild mutualism can (a) significantly enhance coexistence of consumers, (b) induce cyclic dynamics, and (c) give rise to a bi-stability (a 'joint' Allee effect) and potentially catastrophic collapse of both consumer species. © 2012 Elsevier B.V.

Mixing Eucalyptus and Acacia trees leads to fine root over-yielding and vertical segregation between species

The consequences of diversity on belowground processes are still poorly known in tropical forests. The distributions of very fine roots (diameter <1 mm) and fine roots (diameter <3 mm) were studied in a randomized block design close to the harvest age of fast-growing plantations. A replacement series was set up in Brazil with mono-specific Eucalyptus grandis (100E) and Acacia mangium (100A) stands and a mixture with the same stocking density and 50 % of each species (50A:50E). The total fine root (FR) biomass down to a depth of 2 m was about 27 % higher in 50A:50E than in 100A and 100E. Fine root over-yielding in 50A:50E resulted from a 72 % rise in E. grandis fine root biomass per tree relative to 100E, whereas A. mangium FR biomass per tree was 17 % lower than in 100A. Mixing A. mangium with E. grandis trees led to a drop in A. mangium FR biomass in the upper 50 cm of soil relative to 100A, partially balanced by a rise in deep soil layers. Our results highlight similarities in the effects of directional resources on leaf and FR distributions in the mixture, with A. mangium leaves below the E. grandis canopy and a low density of A. mangium fine roots in the resource-rich soil layers relative to monospecific stands. The vertical segregation of resource-absorbing organs did not lead to niche complementarity expected to increase the total biomass production. © 2012 Springer-Verlag Berlin Heidelberg.

Partitioning of net primary production in Eucalyptus and Acacia stands and in mixed-species plantations: Two case-studies in contrasting tropical environments

The introduction of nitrogen fixing species (NFS) in fast-growing tree plantations is an alternative option to reduce fertilizer inputs. However, the success of mixed-species plantations depends on the balance between positive interactions among species (resulting from facilitation and/or complementarity) and the negative effects of interspecific competition.Using a carbon budget approach and coupling measurements of standing biomass, aboveground litterfall and soil CO2 efflux, we assessed the influence of replacing half of eucalypt trees by Acacia mangium on total belowground carbon flux (TBCF), net primary production (NPP) and its partitioning between above- and belowground growth at two tropical sites in Brazil (Itatinga) and in Congo (Kissoko) exhibiting contrasting climates, edaphic conditions and wood productions.Annual soil CO2 efflux (FS) was significantly lower in the acacia monocultures than in eucalypt monocultures and mixed-species stands at both sites. Annual FS was significantly lower at Itatinga compared to Kissoko for all stands while TBCF was significantly lower in the eucalypt stands only. In the eucalypt monocultures we found a significantly lower aboveground NPP (ANPP) and wood production (wood NPP) at Kissoko compared to Itatinga that was almost fully balanced by a significantly higher belowground NPP (BNPP), leading to similar NPP. Similarly, acacia monocultures exhibited significantly higher ANPP and wood NPP at Itatinga than at Kissoko. The mixed-species stands exhibited a significantly lower wood NPP and ANPP than the eucalypt monocultures at the Brazilian site while NPP of the mixture was not significantly different than the average NPP of the two monocultures. At the Congolese site, NPP of the mixture was significantly higher than the average NPP of the two monocultures. NPP was similar in the mixed-species stand and the eucalypt monoculture with a significantly lower partitioning of NPP to belowground production, leading to a one third higher wood biomass at harvest in the mixed-species stand.A positive effect of growing eucalypts with the nitrogen fixing acacia trees on stand wood production occurred at Kissoko but not at Itatinga. Mixed-species plantations with NFS can be advocated at sites where the productive gains resulting from nitrogen fixation are not compromised by other resource limitations. © 2012 Elsevier B.V.

NMDA receptors in the lateral hypothalamus have an inhibitory influence on the tachycardiac response to acute restraint stress in rats

The aim of the present study was to investigate the role of the lateral hypothalamus (LH) and its local glutamatergic neurotransmission in the cardiovascular adjustments observed when rats are submitted to acute restraint stress. Bilateral microinjection of the nonspecific synaptic inhibitor CoCl2 (0.1 nmol in 100 nL) into the LH enhanced the heart rate (HR) increase evoked by restraint stress without affecting the blood pressure increase. Local microinjection of the selective N-methyl-d-aspartate (NMDA) glutamate receptor antagonist LY235959 (2 nmol in 100 nL) into the LH caused effects that were similar to those of CoCl2. No changes were observed in the restraint-related cardiovascular response after a local microinjection of the selective non-NMDA glutamatergic receptor antagonist NBQX (2 nmol in 100 nL) into the LH. Intravenous administration of the muscarinic cholinergic receptor antagonist homatropine methyl bromide (0.2 mg/kg), a quaternary ammonium drug that does not cross the blood-brain barrier, abolished the changes in cardiovascular responses to restraint stress following LH treatment with LY235959. In summary, our findings show that the LH plays an inhibitory role on the HR increase evoked by restraint stress. Present results also indicate that local NMDA glutamate receptors, through facilitation of cardiac parasympathetic activity, mediate the LH inhibitory influence on the cardiac response to acute restraint stress. The bilateral microinjection of the CoCl2 or LY235959 into the LH enhanced the HR increase evoked by restraint stress without affecting the blood pressure increase. Intravenous administration of the homatropine methyl bromide abolished the changes in cardiovascular responses to restraint stress following LH treatment with LY235959. These results suggest that such LH influence is mediated by local NMDA glutamate receptors and involves parasympathetic nervous activation. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Role of the bed nucleus of the stria terminalis in cardiovascular changes following chronic treatment with cocaine and testosterone: A role beyond drug seeking in addiction?

Neural plasticity has been observed in the bed nucleus of the stria terminalis (BNST) following exposure to both cocaine and androgenic-anabolic steroids. Here we investigated the involvement of the BNST on changes in cardiovascular function and baroreflex activity following either single or combined administration of cocaine and testosterone for 10 consecutive days in rats. Single administration of testosterone increased values of arterial pressure, evoked rest bradycardia and reduced baroreflex-mediated bradycardia. These effects of testosterone were not affected by BNST inactivation caused by local bilateral microinjections of the nonselective synaptic blocker CoCl2. The single administration of cocaine as well as the combined treatment with testosterone and cocaine increased both bradycardiac and tachycardiac responses of the baroreflex. Cocaine-evoked baroreflex changes were totally reversed after BNST inactivation. However, BNST inhibition in animals subjected to combined treatment with cocaine and testosterone reversed only the increase in reflex tachycardia, whereas facilitation of reflex bradycardia was not affected by local BNST treatment with CoCl2. In conclusion, the present study provides the first direct evidence that the BNST play a role in cardiovascular changes associated with drug abuse. Our findings suggest that alterations in cardiovascular function following subchronic exposure to cocaine are mediated by neural plasticity in the BNST. The single treatment with cocaine and the combined administration of testosterone and cocaine had similar effects on baroreflex activity, however the association with testosterone inhibited cocaine-induced changes in the BNST control of reflex bradycardia. Testosterone-induced cardiovascular changes seem to be independent of the BNST. © 2013 IBRO.

Population, social equity and changing production patterns

Includes bibliography

Efeito de um treinamento de FNP sobre variáveis biomecânicas em idosos caidores

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Contribuição diferencial de quatro famílias de aves dispersoras de sementes na recuperação de habitats florestais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Engenheiros dos ecossistemas em plantas: modificações arquiteturais de folhas por largatas de Lepidoptera influenciam a estrutura de comunidades de artrópodes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Uso do curativo bio-ativo em pacientes com feridas de origem multifatorial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Main trade trends, trade policy and integration in the greater Caribbean

Includes bibliography

Trajetória do ensino superior privado: o caso da Fundação Eurípedes

Pós-graduação em Educação - FFC