Floristic composition of the tree stratum of a semideciduous mesophytic forest in the municipality of Jahu, SP, Brazil

A floristic study was carried out in an area of semideciduous mesophytic forest, lied in the municipality of Jahu, São Paulo State, Brazil. Due to the fact of the forest be crossed by three small rivers, for the sampling process, the forest was divided in two sampling areas: Area I (under the influence of the rivers) and Area II (without this influence). Differences in the abundance of some species between the two sampling areas were observed.

The absolute configuration of 1-(3 ',4 '-dihydroxycinnamoyl)cyclopentane-2,3-diol from the Amazonian tree Chimarrhis turbinata

An antioxidant, 1-(3',4'-dihydroxycinnamoyl) cyclopentane-2,3-diol [ or ( E)-2,3-dihydroxycyclopentyl-3-(3',4'-dihydroxyphenyl) acrylate ( 1)], and two known trans- and cis-chlorogenic acid methyl esters were isolated from the ethanolic extract of the leaves of Chimarrhis turbinata. The relative configuration of 1 was determined by NMR and by comparison of the circular dichroic spectrum ( CD) with those of the enantiomers of synthetic 3', 4'-dimethoxycinnamoyl analogues. The absolute configuration of one of the synthetic enantiomers was determined using the CD exciton chirality method. This established the structure of naturally occurring 1 as (E)- 2,3-dihydroxycyclopentyl- 3-(3', 4'-dihydroxyphenyl) acrylate.

Evaporative water loss and oxygen uptake in two casque-headed tree frogs, Aparasphenodon brunoi and Corythomantis greeningi (Anura, Hylidae)

Evaporative water loss (EWL) and oxygen uptake ((V) over dot o(2)) was measured in two species of tree frogs with cranial co-ossification, Aparasphenodon brunoi and Corythomantis greeningi. Both species use their head to seal the entrance of bromeliads, tree holes or rocky crevices used as shelters. EWL was significantly reduced in sheltered individuals of both species as compared with those exposed nude to desiccation. EWL per unit area through the head surface was significantly lower than the body skin for A. brunoi but not for C., greeningi. EWL per unit surface area through C. greeningi body skin was about 50% that of A. brunoi, indicating a less permeable skin in the former species. The relationship between cranial coossification and EWL is discussed. ((V) over dot o(2)) in A. brunoi was comparable with other anurans of similar size, whereas in C. greeningi, it was lower than predicted from body mass. Moreover, ((V) over dot o(2)), in C. greeningi showed less sensitivity to temperature increase than in A. brunoi. C. greeningi occurs in a drier environment than A. brunoi, and this appears to be reflected in their EWL and ((V) over dot o(2)) characteristics. (C) 1997 Elsevier B.V.

Mineralogy and forms of potassium in red yellow latosol of a guava (Psidium guajava) tree orchard

A trial was conducted during 1994-95 to study the effect of potassium fertilization on a guava (Psidium guajava L.) culture for 3 years. The control plots (without K) showed fruit production and potassium exportation that did not agree with the levels obtained by chemical analysis of the soil. Physical, chemical, mineralogic and morphologic analyses were performed on the red yellow latosol to identify minerals able to supply potassium, with emphasis on the fact that guava trees have a considerably widespread root system. The results obtained confirmed the presence of minerals in this soil that can supply potassium to the trees through weathering. Feldspars were identified in the silt fraction and micas in the clay fraction by X-ray diffractometry. The determination of total potassium revealed that the silt fraction of the soil had the largest absolute amounts of potassium, followed by clay. However, in view of its greater content, clay was the fraction that contributed most to the total amounts of potassium detected.

Phytosociological study on the tree stratum of a semideciduous mesophytic forest in the municipality of Jau, SP, Brazil

Through the point-centered quarter method, a phytosociological study was carried out in an area of semideciduous mesophytic forest with 190 ha, in the municipality of Jahu,SP. Due to the fact of the forest be crossed by three small rivers, for the sampling process, the Total Area was divided in two sampling areas: the Area I (under the influence of the rivers) and the Area II (without this influence). Some differences between the two regions were observed.

EXTRAFLORAL NECTARIES IN THE TROPICAL TREE GUAREA-MACROPHYLLA (MELIACEAE)

This paper describes the anatomy and morphology of the complex nectary systems of the tropical tree Guarea macrophylla Vahl (Meliaceae) and presents the first record of extrafloral nectaries occurring on reproductive organs (fruits) of a member of the order Sapindales. The extrafloral nectaries of G. macrophylla occur on petioles, petiolules, the abaxial surface of all leaflets, leaf buds, and over the surface of fruits. All extrafloral nectaries are distinctly raised above the surface. Foraging ants collect extrafloral nectar on Guarea trees both day and night. We suggest that the presence of extrafloral nectaries might be a useful taxonomic character for the identification of Guarea species.

Multiobjective linear model for pre-feasibility design of cogeneration systems

This article deals with some methodologies for economic and technical evaluations of cogeneration projects proposed by several authors. A discussion on design philosophy applied to thermal power plants leads to the decision problem of a conflicting, multiobjective formulation that includes the most important parameters. This model is formulated to help decision makers and designers in choosing compromise values for included parameters. (C) 1997 Elsevier B.V. Ltd.

Floristic composition of the tree stratum of a semideciduous mesophytic forest in the municipality of Botucatu, São Paulo state

The floristic composition was studied in an area of semideciduous mesophytic forest, with 120 ha, in the municipality of Botucatu, SP, Brazil. This forest lies on the ascent of the Cuesta of Botucatu. Due to the heterogeneity of the relief, for the sampling process, the forest was divided in three regions: the upper one (comprising the strip of forest on the plateau), middle on (the forestal area lied on the ascent properly said) and the lower one (the strip of forest on the plain). The tree sampling regions showed some differences among them and this must be connected to the differences in the soil.

A REACHABILITY TREE FOR STATECHARTS AND ANALYSIS OF SOME PROPERTIES

Statecharts are an extension to finite state machines with capability for expressing hierarchical decomposition and parallelism. They also have a mechanism called history, to remember the last visit to a superstate. An algorithm to create a reachability tree for statecharts is presented. Also shown is how to use this tree to analyse dynamic properties of statecharts; reachability from any state configuration, usage of transitions, reinitiability, deadlocks, and valid sequence of events. Owing to its powerful notation, building a reachability tree for statecharts presents some difficulties, and we show how these problems were solved in the tree we propose.

Diversity and geographical distribution of phytoplasmas infecting China-tree in Argentina

Yellows diseases associated with phytoplasmas cause high mortality in China-tree (Melia azedarach) in Argentina, but there has been no previous large-scale survey to determine their diversity and geographical distribution. To assess the presence and identity of phytoplasmas affecting this species throughout the country, 425 samples of symptomatic trees collected at different geographic locations were analysed by a polymerase chain reaction (using universal and group-specific primers) and restriction fragment length polymorphism. Phytoplasmas belonging to 16SrIII-B group were detected at almost every location sampled, whereas 16SrXIII-C group phytoplasmas, reported for the first time in Argentina, were only found in two regions sharing similar agro-ecological characteristics (Northeast provinces and Tucuman). Double infections with 16SrIII-B and 16SrXIII-C group phytoplasmas were also recorded. Nucleotide sequencing of the 16S rDNA of three Argentinian 16SrXIII-C group phytoplasma isolates revealed high identity (99.6-99.3%) with the CbY1 isolate reported from Bolivia.

Amazonian tree mortality during the 1997 El Nino drought

In 1997, the Amazon Basin experienced an exceptionally severe El Nino drought. We assessed effects of this rare event on mortality rates of trees in intact rainforest based on data from permanent plots. Long-term (5- to 13-year) mortality rates averaged only 1.12% per year prior to the drought. During the drought year, annual mortality jumped to 1.91% but abruptly fell back to 1.23% in the year following El Nino. Trees dying during the drought dirt not differ significantly in site or species composition from those that died previously, and there was no detectable effect of soil texture on mortality rates. These results suggest that intact Amazonian rainforests are relatively resistant to severe El Nino events.

Phytosociological study of the tree stratum of a semideciduous mesophytic forest in the municipality of Botucatu, SP, Brazil

The phytosociological structure was studied in an area of semideciduous mesophytic forest lied on the ascent of the Cuesta of Botucatu. Once the relief of the area was very heterogeneous, the forest, for the sampling process, was divided in three sampling regions: the upper one (on the plateau), the middle one (on the ascent properly said) and the lower one (on the plain). Through the point-centered method, 1224 (408 in each region) trees were sampled. For this work, only the trees with shaft equal or higher than 1.30m high were considered. The three sampling regions showed some interesting differences in regard to the phytosociologic structure. Once there are differences among the soil of the three regions, the variations in the structure must be connected to the differences in the soil.

Evaluating distributed time-varying generation through a multiobjective index

In the last decade, distributed generation, with its various technologies, has increased its presence in the energy mix presenting distribution networks with challenges in terms of evaluating the technical impacts that require a wide range of network operational effects to be qualified and quantified. The inherent time-varying behavior of demand and distributed generation (particularly when renewable sources are used), need to be taken into account since considering critical scenarios of loading and generation may mask the impacts. One means of dealing with such complexity is through the use of indices that indicate the benefit or otherwise of connections at a given location and for a given horizon. This paper presents a multiobjective performance index for distribution networks with time-varying distributed generation which consider a number of technical issues. The approach has been applied to a medium voltage distribution network considering hourly demand and wind speeds. Results show that this proposal has a better response to the natural behavior of loads and generation than solely considering a single operation scenario.

A class of multiobjective control problems

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