Showing papers by "State University of Campinas published in 2001"

The Genome of the Natural Genetic Engineer Agrobacterium tumefaciens C58

Abstract: The 5.67-megabase genome of the plant pathogen Agrobacterium tumefaciens C58 consists of a circular chromosome, a linear chromosome, and two plasmids. Extensive orthology and nucleotide colinearity between the genomes of A. tumefaciens and the plant symbiont Sinorhizobium meliloti suggest a recent evolutionary divergence. Their similarities include metabolic, transport, and regulatory systems that promote survival in the highly competitive rhizosphere; differences are apparent in their genome structure and virulence gene complement. Availability of the A. tumefaciens sequence will facilitate investigations into the molecular basis of pathogenesis and the evolutionary divergence of pathogenic and symbiotic lifestyles.

Cyclohexane oxidation continues to be a challenge

Abstract: Many efforts have been made to develop new catalysts to oxidize cyclohexane under mild conditions. Herein, we review the most interesting systems for this process with different oxidants such as hydrogen peroxide, tert -butyl hydroperoxide and molecular oxygen. Using H 2 O 2 , Na-GeX has been shown to be a most stable and active catalyst. Mesoporous TS-1 and Ti-MCM-41 are also stable, but the use of other metals such as Cr, V, Fe and Mo leads to leaching of the metal. Homogeneous systems based on binuclear manganese(IV) complexes have also been shown to be interesting. When t -BuOOH is used, the active systems are those phthalocyanines based on Ru, Co and Cu and polyoxometalates of dinuclear ruthenium and palladium. Microporous metallosilicates containing different transition metals showed leaching of the metal during the reactions. Molecular oxygen can be used directly as an oxidant and decreases the leaching of active species in comparison to hydrogen peroxide and tert -butyl hydroperoxide. Metal aluminophosphates (metal: Mn, Fe, Co, Cu, Cr V) are active and relatively stable under such conditions. Mn-AlPO-36 yields directly adipic acid, but large amounts of carboxylic acids should be avoided, as they cause metal leaching from the catalysts. Rare earth exchanged zeolite Y also shows good selectivity and activity. In the last part of the review, novel alternative strategies for the production of cyclohexanol and cyclohexanone and the direct synthesis of adipic acid are discussed.

In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis

Abstract: Gomes BPFA, Ferraz CCR, Vianna ME, Berber VB, Teixeira FB, Souza-Filho FJ. In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis. International Endodontic Journal , 34 , 424‐428, 2001. Aim The aim of this study was to assess, in vitro , the effectiveness of several concentrations of NaOCl (0.5%, 1%, 2.5%, 4% and 5.25%) and two forms of chlorhexidine gluconate (gel and liquid) in three concentrations (0.2%, 1% and 2%) in the elimination of E. faecalis. Methodology A broth dilution test using 24-well cell culture plates was performed and the time taken for the irrigants to kill bacterial cells was recorded. Isolated 24 h colonies of pure cultures of E. faecalis grown on 10% sheep blood plus Brain Heart Infusion (BHI) agar plates were suspended in sterile 0.85% NaCl solution. The cell suspension was adjusted spectrophotometrically to match the turbidity of a McFarland 0.5 scale. One mL of each tested substance was placed on the bottom of wells of 24-well cell culture plates (Corning, NY), including the control group (sterile saline). Six wells were used for each time period and irrigant concentration. Two mL of the bacterial suspension were ultrasonically mixed for 10 s with the irrigants and placed in contact with them for 10, 30, and 45 s; 1, 3, 5, 10, 20, and 30 min; and 1 and 2 h. After each period of time, 1 mL from each well was transferred to tubes containing 2 mL of freshly prepared BHI + neutralizers in order to prevent a residual action of the irrigants. All tubes were incubated at 37 ° C for 7 days. The tubes considered to have positive growth were those which presented medium turbidity during the incubation period. Data were analysed statistically by the Kruskal‐ Wallis test, with the level of significance set at P < 0.05. Results All irrigants were effective in killing E. faecalis , but at different times. Chlorhexidine in the liquid form at all concentrations tested (0.2%, 1% and 2%) and NaOCl (5.25%) were the most effective irrigants. However, the time required by 0.2% chlorhexidine liquid and 2% chlorhexidine gel to promote negative cultures was only 30 s and 1 min, respectively. Conclusions Even though all tested irrigants possessed antibacterial activity, the time required to eliminate E. faecalis depended on the concentration and type of irrigant used.

Species functional redundancy, random extinctions and the stability of ecosystems

Abstract: Summary 1 The level of functional redundancy in natural communities is likely to modulate how ecosystem stability is affected by local species extinction. Thus, extinction should have no effect if all species have similar functions, but a major effect if each carries different functions. 2 We provide a probabilistic framework that, from any distribution of species number across functional groups, generates specific predictions of how functional groups are lost when species become randomly extinct within a given community. In particular, we predict how many species can go extinct before a community loses its first functional group, a useful index for conservation purposes. 3 We demonstrate that the probability of a whole functional group becoming extinct from a given community increases with the number of recognized functional groups (functional richness) but decreases with species richness and functional evenness (the distribution of species across functional groups). 4 Application of this framework to one published data set for a South American plant community suggested that, if local extinction is random, 75% of the species could be lost before the disappearance of the first functional group. 5 However, if redundancy is to be used to determine conservation priorities, the definition of functional groups must be carefully reviewed.

Granular Cu-Co alloys as interacting superparamagnets

Abstract: The anhysteretic magnetization of the granular metallic alloy ${\mathrm{Cu}}_{90}{\mathrm{Co}}_{10}$ is experimentally studied over a wide temperature range (2--700 K). The measurements definitely exclude that this alloy is a simple superparamagnet, even in the high-temperature limit, although some features of granular systems [such as the typical Langevin-like form of the anhysteretic magnetization curves $M(H)]$ are often taken as evidence of superparamagnetism. A phenomenological theory is proposed, explicitly considering that particle moments interact through long-ranged dipolar random forces, whose effect is pictured in terms of a temperature ${T}^{*},$ adding to the actual temperature T in the denominator of the Langevin function argument. This simple formula explains all features of the experimental $M(H)$ curves. The theory indicates that the actual magnetic moments on interacting Co particles are systematically larger than those obtained fitting the magnetic data to a conventional Langevin function. The ${\mathrm{Cu}}_{90}{\mathrm{Co}}_{10}$ granular alloy is therefore identified as an ``interacting superparamagnet'' ISP. The ISP regime appears as separating the high-temperature, conventional superparamagnetic phase from the low-temperature, blocked-particle regime. In this way, a magnetic-regime diagram can be drawn for each granular system. The competition between single-particle and collective blocking mechanisms is briefly analyzed. The proposed interpretation is thought to be applicable to other fine particle systems; its main features and intrinsic limits are discussed.

Alternative successional pathways in the Amazon Basin

Abstract: Summary 1 Successional pathways were evaluated in two Amazonian secondary forest communities with different land-use histories. Sites which had been clearcut without subsequent use were dominated after 6–10 years by the pioneer genus Cecropia (Moraceae), whereas those used for pasture before abandonment were dominated by the pioneer genus Vismia (Clusiaceae). 2 There were 58 plant families and 300 species identified in Cecropia stands but only 43 families and 147 species were identified in Vismia stands. There were 77 species in common (Sorensen similarity = 0.34). 3 Differences in species number and composition of recruiting individuals between stand types were significant and were a function of the dominant pioneer genus, stem density, distance from primary forest, and land-use history. Regeneration under Vismia canopy was dominated by small Vismia individuals (25% of plants < 2 cm basal diameter), whereas regeneration under Cecropia canopy was more diverse and did not include a single young Cecropia. 4 The number of regenerating plants in both secondary stand types dropped off sharply with distance (5, 25, 50, and 100 m) from primary forest, suggesting that seed dispersal was limiting plant recruitment. Species richness also declined with distance and could be explained by the decline in plant density. Species richness in Cecropia stands increased linearly with plant density, but in Vismia stands the richness increase with density was a decelerating function. 5 For the central Amazon, secondary succession involves a more rapid return of primary forest species if deforestation is not followed by use as pasture before abandonment.

Unwanted caesarean sections among public and private patients in Brazil: prospective study.

Abstract: Objective: To assess and compare the preferences of pregnant women in the public and private sector regarding delivery in Brazil Design: Face to face structured interviews with women who were interviewed early in pregnancy, about one month before the due date, and about one month post partum Setting: Four cities in Brazil Participants: 1612 pregnant women: 1093 public patients and 519 private patients Main outcome measures: Rates of delivery by caesarean section in public and private institutions; women9s preferences for delivery; timing of decision to perform caesarean section Results: 1136 women completed all three interviews; 476 women were lost to follow up (376 public patients and 100 private patients) Despite large differences in the rates of caesarean section in the two sectors (222/717 (31%) among public patients and 302/419 (72%) among private patients) there were no significant differences in preferences between the two groups In both antenatal interviews, 70-80% in both sectors said they would prefer to deliver vaginally In a large proportion of cases (237/502) caesarean delivery was decided on before admission: 48/207 (23%) in women in the public sector and 189/295 (64%) in women in the private sector Conclusions: The large difference in the rates of caesarean sections in women in the public and private sectors is due to more unwanted caesarean sections among private patients rather than to a difference in preferences for delivery High or rising rates of caesarean sections do not necessarily reflect demand for surgical delivery What is already known on this topic In Brazil, one quarter of all women deliver in the private sector The rate of caesarean deliveries in the private sector is extremely high (70%) and more than twice that in the public sector, where rates have recently fallen due to a new policy Previous studies in which women were interviewed after birth showed that a substantial proportion of private patients who have caesarean sections would have preferred normal delivery What this study adds In two antenatal interviews, preferences regarding type of delivery were nearly identical among public and private patients and strongly favoured vaginal births Contrary to popular belief, middle and upper class women in Brazil do not want to deliver by caesarean section

Exploring neutrino mixing with low energy superbeams

Abstract: Department of Physics Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397

A Spectral Conjugate Gradient Method for Unconstrained Optimization

Abstract: A family of scaled conjugate gradient algorithms for large-scale unconstrained minimization is defined. The Perry, the Polak—Ribiere and the Fletcher—Reeves formulae are compared using a spectral scaling derived from Raydan's spectral gradient optimization method. The best combination of formula, scaling and initial choice of step-length is compared against well known algorithms using a classical set of problems. An additional comparison involving an ill-conditioned estimation problem in Optics is presented.

Theory of magnetic anisotropy in III 1 − x Mn x V ferromagnets

Abstract: We present a theory of magnetic anisotropy in ${\mathrm{III}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{V}$-diluted magnetic semiconductors with carrier-induced ferromagnetism. The theory is based on four- and six-band envelope function models for the valence-band holes and a mean-field treatment of their exchange interactions with ${\mathrm{Mn}}^{++}$ ions. We find that easy-axis reorientations can occur as a function of temperature, carrier density p, and strain. The magnetic anisotropy in strain-free samples is predicted to have a ${p}^{5/3}$ hole-density dependence at small p, a ${p}^{\ensuremath{-}1}$ dependence at large p, and remarkably large values at intermediate densities. An explicit expression, valid at small p, is given for the uniaxial contribution to the magnetic anisotropy due to unrelaxed epitaxial growth lattice-matching strains. Results of our numerical simulations are in agreement with magnetic anisotropy measurements on samples with both compressive and tensile strains. We predict that decreasing the hole density in current samples will lower the ferromagnetic transition temperature, but will increase the magnetic anisotropy energy and the coercivity.

The effect of elapsed time following bleaching on enamel bond strength of resin composite.

Abstract: Recent studies have concluded that carbamide peroxide bleaching agents significantly affect the bond strength of composite to bleached enamel. This study evaluated the effects of bleaching regimen with different carbamide peroxide concentrations and post-treatment times on composite bond strength to enamel. Two hundred and four flat buccal and lingual enamel surfaces obtained from erupted sound third molars were randomly divided into 17 groups (n = 12). Sixteen experimental groups comprised the evaluation of four carbamide peroxide home bleaching agents (Opalescence 10%-20% and Whiteness 10%-16%) and four time intervals after bleaching (one day, one, two and three weeks). Specimens of control group were not submitted to bleaching and were stored in artificial saliva at 37 degrees C for 10 days. The specimens of experimental groups were exposed to one daily application of carbamide peroxide for six hours for 10 consecutive days. After each daily treatment and post-bleaching, the specimens were stored in artificial saliva solution. Bonds were formed with Scotchbond MP and Z-100 composite resin, and shear bond test was carried out 24 hours after adhesive-composite application. Two-way ANOVA showed that the bond strengths were significantly different (p < 0.05). For the first two weeks post-bleaching, the bond strengths of resin to enamel were low. After a lapse of three weeks, the bond strength returned to that of the untreated control group. Increased concentration did not prolong the time needed prior to bonding.

Algorithm 813: SPG—Software for Convex-Constrained Optimization

Abstract: Fortran 77 software implementing the SPG method is introduced. SPG is a nonmonotone projected gradient algorithm for solving large-scale convex-constrained optimization problems. It combines the classical projected gradient method with the spectral gradient choice of steplength and a nonmonotone line-search strategy. The user provides objective function and gradient values, and projections onto the feasible set. Some recent numerical tests are reported on very large location problems, indicating that SPG is substantially more efficient than existing general-purpose software on problems for which projections can be computed efficiently.

H/sub 2/ and H/sub /spl infin// robust filtering for convex bounded uncertain systems

Abstract: Investigates robust filtering design problems in H/sub 2/ and H/sub /spl infin// spaces for continuous-time systems subjected to parameter uncertainty belonging to a convex bounded-polyhedral domain. It is shown that, by a suitable change of variables, both designs can be converted into convex programming problems written in terms of linear matrix inequalities. The results generalize the ones available in the literature to date in several directions. First, all system matrices can be corrupted by parameter uncertainty and the admissible uncertainty may be structured. Then, assuming the order of the uncertain system is known, the optimal guaranteed performance H/sub 2/ and H/sub /spl infin// filters are proven to be of the same order as the order of the system. A numerical example illustrate the theoretical results.

Estado e políticas (públicas) sociais

Abstract: To better understand and assess the social public policies implemented by a government, one needs to comprehend the conception of State and social policies underlying these actions and intervention programs. In this field, different visions of society, State and educational policy yield different intervention projects. Focusing on the Marxist and neoliberal approaches of the topic, this text seeks to bring forward elements that contribute to understand this relationship.

Robust H/spl infin/ filter design for uncertain linear systems with multiple time-varying state delays

Abstract: The problem of robust H/spl infin/ filtering for continuous-time uncertain linear systems with multiple time-varying delays in the state variables is investigated. The uncertain parameters are supposed to belong to a given convex bounded polyhedral domain. The aim is to design a stable linear filter assuring asymptotic stability and a prescribed H/spl infin/ performance level for the filtering error system, irrespective of the uncertainties and the time delays. Sufficient conditions for the existence of such a filter are established in terms of linear matrix inequalities, which can be efficiently solved by means of powerful convex programming tools with global convergence assured. An example illustrates the proposed methodology.

Chromobacterium violaceum: a review of pharmacological and industiral perspectives.

Abstract: Violet-pigmented bacteria, which have been described since the end of the 19th century, are occasionally the causative agent of septicemia and sometimes cause fatal infection in human and animals. Bacteria, producing violet colonies due to the production of a nondiffus- ible pigment violacein, were classified as a redefined genus Chromobacterium. Chromobacte- rium violaceum is Gram-negative, and saprophyte from soil and water is normally considered nonpathogenic to human, but is an opportunistic pathogen of extreme virulence for human and animals. The biosynthesis and biological activities of violacein and the diverse effects of this pigment have been studied. Besides violacein, C. violaceum produces other antibiotics, such as aerocyanidin and aerocavin, which exhibit in vitro activity against both Gram-negative and Gram-positive bacteria. 3,6-Dihydroxyindoxazene and Y-TO678h exhibit a selective activity against Gram-negative bacteria. Arphamenine A and B, and FR901228, that enhanced immunoresponse, and potentiators of β-lactam antibiotics and chelators such as ferrioxamine exhibit important clinical potential applications. Lipopolysaccharides and polyhydroxyesters together with several enzymes appear as important metabolites with biotechnological applica- tions. Many of these metabolites were already studied at the genome level.

Seasonality of insect succession and pig carcass decomposition in a natural forest area in southeastern Brazil.

Abstract: In this study, successional patterns, relative abundance of larvae and adults of sarcosaprophagous insects, carcass decay, diversity and seasonality of species, and their potential as forensic indicators were studied. Four experiments were carried out in each season in a natural area of southeastern Brazil. Two pigs (Sus scrofa L.) were used in each experiment and were exposed to sunlight and shade, respectively. The Calliphoridae outnumbered the Sarcophagidae in specimens collected and reared from the carcasses. More insects were collected from carcasses exposed to the sun, while a larger number of specimens were reared from those in the shade. Temperature and rainfall influenced the stages of carcass decay and insect activity and abundance. Chrysomya albiceps was the most abundant species in all four experiments. The carcasses were used as a protein source and substratum for oviposition. The dark putrefaction and fermentation stages yielded more flies than the other stages. These results show that flies are important in carcass decay and are, therefore, also of forensic importance. Seven species can be considered valuable forensic indicators in Southeastern Brazil. However, only three species were useful as forensic indicators in wooded areas: P. intermutans, H. segmentaria, and H. semidiaphana.

Ten years of genetic fuzzy systems: current framework and new trends

Abstract: Although fuzzy systems demonstrated their ability to solve different kinds of problems in various applications, there is an increasing interest on augmenting them with learning capabilities. Two of the most successful approaches to hybridise fuzzy systems with adaptation methods have been made in the realm of soft computing: neuro-fuzzy systems and genetic fuzzy systems hybridise the approximate reasoning method of fuzzy systems with the learning capabilities of neural networks and evolutionary algorithms. The article focuses on genetic fuzzy systems, paying special attention to genetic fuzzy rule based systems, giving a brief overview of the field.

The libraries that made SUCEST

Abstract: A large-scale sequencing of sugarcane expressed sequence tags (ESTs) was carried out as a first step in depicting the genome of this important tropical crop. Twenty-six unidirectional cDNA libraries were constructed from a variety of tissues sampled from thirteen different sugarcane cultivars. A total of 291,689 cDNA clones were sequenced in their 5’ and 3’end regions. After trimming low-quality sequences and removing vector and ribosomal RNA sequences, 237,954 ESTs potentially derived from protein-encoding messenger RNA (mRNA) remained. The average insert size in all libraries was estimated to be 1,250bp with the insert length varying from 500 to 5,000 bp. Clustering the 237,954 sugarcane ESTs resulted in 43,141clusters, from which 38% had no matches with existing sequences in the public databases. Around 53% of the clusters were formed by ESTs expressed in at least two libraries while 47% of the clusters are formed by ESTs expressed in only one library. A global analysis of the ESTs indicated that around 33% contain cDNA clones with full-length insert.

Apical extrusion of debris and irrigants using two hand and three engine-driven instrumentation techniques.

Abstract: Aim To evaluate the weight of debris and irrigant volume extruded apically from extracted teeth in vitro after endodontic instrumentation using the balanced force technique, a hybrid hand instrumentation technique, and three engine-driven techniques utilizing nickel–titanium instruments (ProFile .04, Quantec 2000 and Pow-R). Methodology Five groups of 20 extracted human teeth with single canals were instrumented using one or other of five techniques: balanced force, hybrid, Quantec 2000, ProFile .04, or Pow-R. Debris extruded from the apical foramen during instrumentation were collected into preweighed 1.5 mL tubes. Following instrumentation, the volume of extruded irrigant fluid was determined by visual comparison to control centrifuge tubes filled with 0.25 mL increments of distilled water. The weight of dry extruded dentine debris was also established. Results Overall, the engine-driven techniques extruded less debris than the manual ones. However, there was no statistical difference between the balanced force technique and the engine-driven methods. The volume of irrigant extruded through the apex was directly associated with the weight of extruded debris, except within the ProFile group. The hybrid technique was associated with the greatest extrusion of both debris and irrigant. Conclusions Overall, the engine-driven nickel–titanium systems were associated with less apical extrusion.