Absorção de molibdênio pela cana de açúcar variedade Co 419, em função da idade

In this paper the authors describe the results obtained from the determination of molybdenum in sugar cane plant, grown in soils and climate prevailing in Piracicaba, State of São Paulo, Brazil. The molybdenum was determined in samples cut monthly from the 8th to 14th month, from an experiment consisting of 6 plots, 3 fertilized and 3 unfertilized. The fertilized treatment received 40 kg N (ammonium sulfate) 100 kg P2O3, (superphosphate) and 40 kg K2O (potassium chloride) per hectare, just before planting. Molybdenum was determined by thiocyanate-stannous chloride method, using carbon tetrachloride-butyl alcohol misture, for extrating the colored complex. The results obtained show a parallelism in the absorption of molybdenum by the plants of both treatments. The concentration of molybdenum in the stalks have a tendency to decrease, where as it kept more or less constant in leaves, with a exception in the 14° month when it rised probable because of a migration of molybdenum of the stalks to the leaves. The total amount molybdenum taken up was higher with the fertilized plot due its greater mass prodution.

Experiments in square lattice with a common treatment in all blocks

This paper deals with a generalization of square lattice designs, with k² treatments in blocks of k + 1 plots, the extra plot in each block receiving a standard treatment, the same for all blocks. The new design leads to lower variances for contrasts between adjusted treatment means

Efeitos de reguladores de crescimento nas características organográficas e na produtividade do morangueiro 'Sequóia'

Este estudo teve por objetivo verificar a possibilidade de se melhorar a produção de pseudofrutos de morangueiro 'Sequóia' e de promover alterações morfológicas nas plantas tratadas com fitoreguladores. O experimento instalado no campo e delineado em blocos casualizados, constou de 5 tratamentos e 4 blocos, com 12 plantas por parcela. Além do controle, foram testados os reguladores vegetais ácido giberélico (GA3) e ácido naftalenoacético NAA e os bioestimulantes Ergostim e Atonik. A dose total foi de 30ppm, parcelada em 3 aplicações, a intervalos semanais, iniciadas após o inicio do florescimento. Não houve diferenças significativas entre o controle e os demais tratamentos quanto aos parâmetros organográficos estudados, embora a conformação das plantas tratadas com GA3 tenha sido alterada. A análise dos dados de produção não revelaram diferenças significativas entre o controle e os tratamentos, apesar do número de morangos produzidos pelo GA3 e pelo controle tenha sido superior ao dos demais. O peso, o comprimento e o diâmetro dos pseudofrutos não foram alterados pelos tratamentos. Foi utilizado o modelo estatístico "split-plot", a fim de detectar a interação entre os tratamentos e as épocas de produção. As épocas de produção interferiram no número e tamanho de morangos nos diferentes tratamentos. Atonik induziu mo rangos com teores mais elevados de açúcares solúveis em relação ao controle e ao Ergostim.

Abundância de microartrópodes do solo em fragmentos de mata com araucária no sul do Brasil

The abundance of soil microarthropods from seven fragments of Araucaria Forest, Muitos Capões, Rio Grande do Sul, Brazil, was compared. The size of the fragments ranged from 0.25 ha to 35 ha, the two largest fragments are situated within the Aracuri Ecological Station and the remaining five are situated in a cattle ranching farm. In June 2000, three plots (10 m x 10 m) were established in the central area of each patch, and three soil cores (7 cm diameter x 6 cm deep) were taken per plot. The abundance of microarthropods in the upper six centimeters (soil + litter) varied between 63209 and 102704 ind.m-2, with oribatid mites (Acari, Cryptostigmata) being dominant in all fragments (between 46.9 % and 61.3 % of total individuals). Most microarthropod groups presented a decrease in abundance with decreasing fragment area, with a statistically significant difference between smaller and larger fragments. The proportion of oribatids also decreased with decreasing fragment area. The results suggest that the growing fragmentation process of Araucaria forests in southern Brazil, associated to a tendency for reducing the size of remnant fragments, can affect the abundance of soil microarthropods, and therefore, the quality and health of this ecosystem.

Diversity and habitat preference of medium and large-sized mammals in an urban forest fragment of southwestern Amazon

We assessed the species composition and abundance of medium and large-sized mammals in an urban forest fragment in the Brazilian Amazon, and recorded the preference of some species for particular phytophysiognomies. We placed nine transects with 20 sand plots each in three phytophysiognomies: open rainforest with a dominance of bamboos (OFB), open rainforest with palm trees (OFP), and dense rainforest (DF). We calculated species abundance as the number of records/plot.day, in a total of 2,700 plots.day. We recorded twelve mammal species; Sylvilagus brasiliensis (Linnaeus, 1758) and Dasyprocta fuliginosa (Wagler, 1831) were the most abundant. The results differed among phytophysiognomies: DF presented the highest mammal diversity, whereas the species composition of OFP was less similar than that of other phytophysiognomies. Rodents showed higher preference for OFP and Sylvilagus brasiliensis was more abundant in OFB. The study area showed high species richness, with the occurrence of mesopredators, but there was a predominance of common species adaptable to disturbed environments, which reflects the severe isolation degree of the forest fragment and the hunting pressure that is still present.

Stochastic dominance and absolute risk aversion

In this paper we propose the infimum of the Arrow-Pratt index of absolute risk aversion as a measure of global risk aversion of a utility function. We then show that, for any given arbitrary pair of distributions, there exists a threshold level of global risk aversion such that all increasing concave utility functions with at least as much global risk aversion would rank the two distributions in the same way. Furthermore, this threshold level is sharp in the sense that, for any lower level of global risk aversion, we can find two utility functions in this class yielding opposite preference relations for the two distributions.

Efeito de alguns curares naturais e da d-Tubocurarina retardando o tempo de coagulação e o tempo de protombina do sangue humano

In this paper the author points out to a old question of about 200 years ago in wich two kinds of opinions were discussed. BANCROFT and FONTANA in one hand atributes for the Indian arrow poison (curare) the propriety of uncoagulate the blood, and C. BEBNAHDJ, B. RODRIGUES and others made an contradictory opinion upon this subject. In our experiments, we utilized 4 curares samples from indians who lives near the Brazilian border at Colombia, the famous Ticunas poison, and the alkaloid d-Tubocurarine. These poisons were added in form of emulsion in saline to the blood and blood plasma in order to perform two kinds of experiments. In one serie of experiments we observed the effect of curare on human blood coagulation time according to LEE-WHITE technic puting 0.5 ml of the various poisons emulsions previously into the tube. By this method, we have found that the emulsion containing 0.1 g of the poison in 10 ml saline was the most effective (Table II), therefore we used this curare emulsion concentration in the other serie of experiments, in which we tested the action of these venoms on the human blood plasma prothrombins time, (Quick Technic) adding 0.1 ml of the saline poison emulsion to each 0.1 ml of human blood plasma. Results from these experiments can be seen on Table II. These experiments we have tried on one sample of human blood plasma plus the differents curares samples; and in another opportunity four samples of human blood plasma were tried with the curare from Ticunas indians (the most effective in this respect). Results from these experiments may be seen on Table III. All the poison tried in our experiments was previously tested on toads legs (B. crucifer) to verify his curares action. All times obtained with the experiments above, show highly significant results (P<001) when compared with the blood and blood plasma mixed with in the same volume of saline. Our results, point out that BANCROFT and FONTANA views upon the effect of curare on blood clothing time were correct. Curares enhance the blood clothing time "in vitro". But, in other hand, the work in that matter by NESI (6), and TISTHOUND (7) showing that d-Tubocurarine had no significant effect on blood clothing time of man and dogs "in vivo", made possible to conclude that the observations of C. BERNARD, B. RODRIGUES and others were also true. These discordance of opinions, we believe, may result as BANCROFT and FONTANA researches, were wade "in vitro" whereas C. Bernard, B. Rodrigues and others performed their experiments "in vivo".

Validation of an analytical method for nitrous oxide (N2O) laughing gas by headspace gas chromatography coupled to mass spectrometry (HS-GC-MS): Forensic application to a lethal intoxication.

Drug abuse is a widespread problem affecting both teenagers and adults. Nitrous oxide is becoming increasingly popular as an inhalation drug, causing harmful neurological and hematological effects. Some gas chromatography-mass spectrometry (GC-MS) methods for nitrous oxide measurement have been previously described. The main drawbacks of these methods include a lack of sensitivity for forensic applications; including an inability to quantitatively determine the concentration of gas present. The following study provides a validated method using HS-GC-MS which incorporates hydrogen sulfide as a suitable internal standard allowing the quantification of nitrous oxide. Upon analysis, sample and internal standard have similar retention times and are eluted quickly from the molecular sieve 5Å PLOT capillary column and the Porabond Q column therefore providing rapid data collection whilst preserving well defined peaks. After validation, the method has been applied to a real case of N2O intoxication indicating concentrations in a mono-intoxication.

Gestió forestal de masses d'arboç (Arbutus unedo) en regeneració després de foc al terme municipal d'Esparreguera

Els incendis forestals són una pertorbació amb un paper decisiu en l’estructura i dinàmica dels ecosistemes mediterranis. La majoria de les seves espècies vegetals presenten mecanismes de resposta al foc, com la germinació de llavors i la rebrotada d’individus cremats. Les masses forestals regenerades a partir de rebrots assoleixen densitats massa altes i una baixa producció, i, per tant, és fonamental dur a terme una gestió mitjançant tractaments silvícoles. El principal objectiu d’aquest projecte és quantificar l’efecte de la selecció de rebrots i la selecció de rebrots més la desbrossada sobre el creixement de l’Arbutus unedo. S’han estudiat 12 parcel—les en regeneració després dels incendis de 1985, 1986 i 1994 al terme municipal d’Esparreguera. Els resultats mostren que els dos tractaments afavoreixen de la mateixa manera el creixement dels peus d’Arbutus unedo, a causa de la disminució de la competència intraespecífica i interespecífica. La desbrossada (a nivell de parcel—la, no d’individu), no obstant, provoca un increment probablement perjudicial de l’alçada dels rebrots, per la major disponibilitat de llum. Per tal de proposar un model de gestió forestal, s’ha realitzat una anàlisi multicriterial dels diferents escenaris, on s’han considerat altres criteris, com són el model de combustible, la possibilitat de pastura i el cost econòmic. L’alternativa preferida en els boscos d’Arbutus unedo és la selecció de rebrots i la desbrossada.

How reliable is the monitoring of permanent vegetation plots? A test with multiple observers

Questions: A multiple plot design was developed for permanent vegetation plots. How reliable are the different methods used in this design and which changes can we measure? Location: Alpine meadows (2430 m a.s.l.) in the Swiss Alps. Methods: Four inventories were obtained from 40 m(2) plots: four subplots (0.4 m(2)) with a list of species, two 10m transects with the point method (50 points on each), one subplot (4 m2) with a list of species and visual cover estimates as a percentage and the complete plot (40 m(2)) with a list of species and visual estimates in classes. This design was tested by five to seven experienced botanists in three plots. Results: Whatever the sampling size, only 45-63% of the species were seen by all the observers. However, the majority of the overlooked species had cover < 0.1%. Pairs of observers overlooked 10-20% less species than single observers. The point method was the best method for cover estimate, but it took much longer than visual cover estimates, and 100 points allowed for the monitoring of only a very limited number of species. The visual estimate as a percentage was more precise than classes. Working in pairs did not improve the estimates, but one botanist repeating the survey is more reliable than a succession of different observers. Conclusion: Lists of species are insufficient for monitoring. It is necessary to add cover estimates to allow for subsequent interpretations in spite of the overlooked species. The choice of the method depends on the available resources: the point method is time consuming but gives precise data for a limited number of species, while visual estimates are quick but allow for recording only large changes in cover. Constant pairs of observers improve the reliability of the records.

Note on a theorem of Bousfield and Friedlander

We examine the proof of a classical localization theorem of Bousfield and Friedlander and we remove the assumption that the underlying model category be right proper. The key to the argument is a lemma about factoring in morphisms in the arrow category of a model category.

Revealed cardinal preference

I prove that as long as we allow the marginal utility for money (lambda) to vary between purchases (similarly to the budget) then the quasi-linear and the ordinal budget-constrained models rationalize the same data. However, we know that lambda is approximately constant. I provide a simple constructive proof for the necessary and sufficient condition for the constant lambda rationalization, which I argue should replace the Generalized Axiom of Revealed Preference in empirical studies of consumer behavior. 'Go Cardinals!' It is the minimal requirement of any scientifi c theory that it is consistent with the data it is trying to explain. In the case of (Hicksian) consumer theory it was revealed preference -introduced by Samuelson (1938,1948) - that provided an empirical test to satisfy this need. At that time most of economic reasoning was done in terms of a competitive general equilibrium, a concept abstract enough so that it can be built on the ordinal preferences over baskets of goods - even if the extremely specialized ones of Arrow and Debreu. However, starting in the sixties, economics has moved beyond the 'invisible hand' explanation of how -even competitive- markets operate. A seemingly unavoidable step of this 'revolution' was that ever since, most economic research has been carried out in a partial equilibrium context. Now, the partial equilibrium approach does not mean that the rest of the markets are ignored, rather that they are held constant. In other words, there is a special commodity -call it money - that reflects the trade-offs of moving purchasing power across markets. As a result, the basic building block of consumer behavior in partial equilibrium is no longer the consumer's preferences over goods, rather her valuation of them, in terms of money. This new paradigm necessitates a new theory of revealed preference.

Contracting over Prices

We defi ne a solution concept, perfectly contracted equilibrium, for an intertemporal exchange economy where agents are simultaneously price takers in spot commodity markets while engaging in non-Walrasian contracting over future prices. In a setting with subjective uncertainty over future prices, we show that perfectly contracted equi- librium outcomes are a subset of Pareto optimal allocations. It is a robust possibility for perfectly contracted equilibrium outcomes to di er from Arrow-Debreu equilibrium outcomes. We show that both centralized banking and retrading with bilateral contracting can lead to perfectly contracted equilibria.

Chemical genetic analysis of cdc2p : new insights into the regulation of cytokinesis in "Schizosaccharomyces pombe"

RÉSUMÉ La protéine kinase cyciine-cdc2p (Cdk) joue un rôle fondamental dans la progression du cycle cellulaire dans la levure de fission Schizosaccharomyces pombe. Nous avons étudié le rôle de cdc2p dans la régulation de la cascade de septation ou SIN (septation initiation network) en mitose et en méiose. Le SIN contrôle l'initiation de la cytokinèse à la fin de la mitose, et est supposé être négativement régulé par cdc2p. Nous avons mutagénéisé le site actif de cdc2p afin qu'il puisse lier un analogue de l'ATP (PP1) qui agit comme inhibiteur. Cet analogue ne peut pas lier la kinase de type sauvage. Cette approche dite «chemical genetics» permet une meilleure résolution temporelle comparée à l'approche classique utilisant les mutants sensibles à une température élevée. Nous avons montré que ce mutant cdc2-as (analogue sensitive) est fonctionnel et que, in vitro, l'activité kinase est inhibée en présence de l'analogue. Les cellules portant cette mutation, contrairement aux cellules de type sauvage s'arrêtent de manière irréversible soit en G2 soit en G1 et G2, suivant la concentration de l'inhibiteur. L'inactivation de cdc2p-as dans des cellules arrêtées en métaphase conduit au recrutement asymétrique des protéines du SIN sur le pôle du fuseau mitotique et au recrutement des composants du SIN, ainsi que de la ß-(1,3)glucan synthase à l'anneau contractile. De plus, nos résultats montrent que l'orthologue de la phosphatase cdc14p dans S. pombe, fip1p/clp1p, joue un rôle dans la régulation de la localisation des protéines du SIN suite à l'inactivation de cdc2p. Finalement, l'activité de cdc2p est requise pour maintenir la polo-like kinase plo1p sur les pôles du fuseau mitotique dans les premiers stages de la mitose. C'est pourquoi nous concluons que l'inactivation de cdc2p est suffisante pour activer le SIN et promouvoir la cytokinèse. Dans une étude séparée, nous avons caractérisé des potentiellement nouveaux composants ou régulateurs du SIN qui ont été isolés dans deux criblages génétiques visant à isoler des mutants atténuants la signalisation du SIN. Summary : The cyclin dependent protein kinase (Cdk) cdc2p plays a central role in the cell cycle progression of fission yeast Schizosaccharomyces pombe. We have studied the role of cdc2p in regulating the septation initiation network (SIN) in mitosis and meiosis. The SIN regulates the initiation of cytokinesis at the end of mitosis and is thought to be inhibited by cdc2p. We have mutated the active site of cdc2p to permit binding of an inhibitory ATP analogue (PP1), which is unable to bind unmodified kinases. This "chemical genetic" approach provides a much higher temporal resolution than it can be achieved with classical temperature-sensitive mutants. We demonstrate that cdc2-as (analogue sensitive) is functional and that addition of PP1 inhibits cdc2p kinase activity in vitro. Cells carrying the cdc2-as allele, but not cdc2+, undergo reversible cell cycle arrest following addition of PP1 either in G2, or at both major commitment points in the cell cycle (G1 and G2), depending upon the concentration of PP1. Inactivation of cdc2p-as in cells arrested in early mitosis promotes both the asymmetric recruitment of SIN proteins to the spindle pole bodies (SPBs), and the recruitment of the most downstream SIN components and ß-(1,3)-glucan synthase to the contractile ring. Furthermore, our results indicate that the S. pombe orthologue of Cdc14p, flp1p/clp1p, plays a role in regulating the relocalisation of SIN proteins following inactivation of cdc2p, and that cdc2p activity is required to retain the polo like kinase plot p on the SPBs in early mitosis. Thus, we conclude that inactivation of cdc2p is sufficient to activate the SIN and to promote cytokinesis. In a separate study, we have initially characterised potential novel components or regulators of the SIN pathway identified by two genetic screens for mutants attenuating SIN signaling.