Study of the influence of simultaneous variation of magnetic material microstructural features on domain wall dynamics

The magnetic Barkhausen noise (MBN) is a phenomenon sensitive to several kinds of magnetic material microstructure changes, as well as to variations in material plastic deformation and stress. This fact stimulates the development of MBN-based non-destructive testing (NDT) techniques for analyzing magnetic materials, being the proposition of such a method, the main objective of the present study. The behavior of the MBN signal envelope, under simultaneous variations of carbon content and plastic deformation, is explained by the domain wall dynamics. Additionally, a non-destructive parameter for the characterization of each of these factors is proposed and validated through the experimental results. (C) 2010 Elsevier B.V. All rights reserved.

Modeling the kinetics of the coalescence of water droplets in crude oil emulsions subject to an electric field, with the cellular automata technique

In this study, the concept of cellular automata is applied in an innovative way to simulate the separation of phases in a water/oil emulsion. The velocity of the water droplets is calculated by the balance of forces acting on a pair of droplets in a group, and cellular automata is used to simulate the whole group of droplets. Thus, it is possible to solve the problem stochastically and to show the sequence of collisions of droplets and coalescence phenomena. This methodology enables the calculation of the amount of water that can be separated from the emulsion under different operating conditions, thus enabling the process to be optimized. Comparisons between the results obtained from the developed model and the operational performance of an actual desalting unit are carried out. The accuracy observed shows that the developed model is a good representation of the actual process. (C) 2010 Published by Elsevier Ltd.

Scheduling in a two-machine flowshop for the minimization of the mean absolute deviation from a common due date

This paper addresses the minimization of the mean absolute deviation from a common due date in a two-machine flowshop scheduling problem. We present heuristics that use an algorithm, based on proposed properties, which obtains an optimal schedule fora given job sequence. A new set of benchmark problems is presented with the purpose of evaluating the heuristics. Computational experiments show that the developed heuristics outperform results found in the literature for problems up to 500 jobs. (C) 2007 Elsevier Ltd. All rights reserved.

Understanding the strategies of late-movers in International Manufacturing

This paper analyzes the internationalization of new multinationals from emerging countries. It also focuses on Production`s role in firm internationalization, a subject seldom addressed because the discipline of International Manufacturing is still embryonic, while International Business tends to overlook production. The authors integrate International Business and International Manufacturing concepts and frameworks in order to analyze new multinationals from emerging countries, using the empirical evidence of a survey plus case studies of Brazilian multinationals for understanding late-movers` strategies and competences, with emphasis on production. (C) 2009 Elsevier B.V. All rights reserved.

Self-organized criticality and the predictability of human behavior

The behavior of normal individuals and psychiatric patients vary in a similar way following power laws. The presence of identical patterns of behavioral variation occurring in individuals with different levels of activity is suggestive of self-similarity phenomena. Based on these findings, we propose that the human behavior in social context can constitute a system exhibiting self-organized criticality (SOC). The introduction of SOC concept in psychological theories can help to approach the question of behavior predictability by taking into consideration their intrinsic stochastic character. Also, the ceteris paribus generalizations characteristic of psychological laws can be seen as a consequence of individual level description of a more complex collective phenomena. Although limited, this study suggests that, if an adequate level of description is adopted, the complexity of human behavior can be more easily approached and their individual and social components can be more realistically modeled. (C) 2009 Elsevier Ltd. All rights reserved.

The choice of the best among the shortest routes in transparent optical networks

This work introduces the problem of the best choice among M combinations of the shortest paths for dynamic provisioning of lightpaths in all-optical networks. To solve this problem in an optimized way (shortest path and load balance), a new fixed routing algorithm, named Best among the Shortest Routes (BSR), is proposed. The BSR`s performance is compared in terms of blocking probability and network utilization with Dijkstra`s shortest path algorithm and others algorithms proposed in the literature. The evaluated scenarios include several representative topologies for all-optical networking and different wavelength conversion architectures. For all studied scenarios, BSR achieved superior performance. (C) 2010 Elsevier B.V. All rights reserved.

Long-term aging of fiber-cement corrugated sheets - The effect of carbonation, leaching and acid rain

This paper studies the performance of fiber-cement corrugated sheets exposed to long-term weathering, exploring the effect of different environments on fiber-cement degradation. Fiber-cement corrugated sheets that had been exposed to weathering, and in place for more than 30-years, were collected from two different Brazilian cities (Sao Paulo and Criciuma). Mechanical properties (MOR, MOE and fracture toughness) were tested on samples removed from the corrugated sheets. Microstructure was evaluated by X-ray diffraction, SEM with EDS analysis, MIP and TG. The results show that the 37-year-old asbestos-cement corrugated sheets from Sao Paulo presented similar characteristics to those of the non-aged asbestos-cement readily available on the market place. Conversely, deterioration of the asbestos-cement from the industrial area of Criciuma is related to acidic attack, along with carbonation and leaching as a consequence of continued exposition to acid rain during several decades. This process resulted in higher porosity and lower mechanical strength, revealing that leaching mechanisms can have important effect on the performance of thin fiber-cement sheets. (c) 2007 Elsevier Ltd. All rights reserved.

The role of seasonality on the inhibitory effect of Brazilian green propolis on the oxidative metabolism of neutrophils

The reactive oxygen species (ROS) produced by neutrophils are involved in the pathogenesis of several diseases, for which the intake of antioxidants could benefit patients either as a prophylactic or therapeutic treatment. Propolis is among the known antioxidants, and its chemical composition may vary under the influence of seasonality, which may interfere in its biological properties. This work evaluates the role of seasonality on the production of some important compounds of propolis samples produced monthly from November 2001 through October 2002 as well as the effect of these samples on the oxidative metabolism of stimulated neutrophils, by using both luminol and lucigenin to produce chemiluminescence (CLlum and CLluc, respectively). The cytotoxicity of the most active extracts to neutrophils was also investigated. The inhibitory effect of the propolis samples varied significantly during the studied period for both assays (3.4 +/- 1.1 to 16.0 +/- 1.1 mu g/mL for CLlum and 6.2 +/- 2.0 to 30.0 +/- 5.0 mu g/mL for CLluc), which was also observed in the quantitative profile of the main analyzed compounds (aromadendrin-4`-methyl ether, artepillin C, and baccharin). This effect started to become more prominent during the fall and, among all the studied extracts, the one obtained in May displayed the highest inhibitory effect on CL production (3.4 +/- 1.1 mu g/mL for alum and 6.2 +/- 2.0 mu g/mL for CLluc). The HPLC qualitative profiles of the extracts of propolis samples were quite similar, but there was a huge variation in terms of quantitative profile. It seems that aromadendrin-4`-methyl ether and baccharin play an essential role in the antioxidant activity, while artepillin C is not very important for this effect. The extracts presenting the highest antioxidant activity were produced in May, June, and August, and they did not display cytotoxicity at 25 mu g/mL; quercetin, used as control, was not toxic to neutrophils at 8.5 mu g/mL (C) 2010 Elsevier B.V. All rights reserved.

The effects of dietary supplementation of methionine on genomic stability and p53 gene promoter methylation in rats

Methionine is a component of one-carbon metabolism and a precursor of S-adenosylmethionine (SAM), the methyl donor for DNA methylation. When methionine intake is high, an increase of S-adenosylmethionine (SAM) is expected. DNA methyltransferases convert SAM to S-adenosylhomocysteine (SAH). A high intracellular SAH concentration could inhibit the activity of DNA methyltransferases. Therefore, high methionine ingestion could induce DNA damage and change the methylation pattern of tumor suppressor genes. This study investigated the genotoxicity of a methionine-supplemented diet. It also investigated the diet`s effects on glutathione levels, SAM and SAH concentrations and the gene methylation pattern of p53. Wistar rats received either a methionine-supplemented diet (2% methionine) or a control diet (0.3% methionine) for six weeks. The methionine-supplemented diet was neither genotoxic nor antigenotoxic to kidney cells, as assessed by the comet assay. However, the methionine-supplemented diet restored the renal glutathione depletion induced by doxorubicin. This fact may be explained by the transsulfuration pathway, which converts methionine to glutathione in the kidney. Methionine supplementation increased the renal concentration of SAH without changing the SAM/SAH ratio. This unchanged profile was also observed for DNA methylation at the promoter region of the p53 gene. Further studies are necessary to elucidate this diet`s effects on genomic stability and DNA methylation. (C) 2011 Elsevier ay. All rights reserved.

Chetoneura shennonggongensis, a new species of cave-dwelling Keroplatini from China (Diptera : Keroplatidae), with a discussion of the position of Chetoneura

Chetoneura shennonggongensis Amorim & Niu, sp. n., inhabiting caves in East China, is described based on the adult male and female, plus larva. Chetoneura Colless, previously associated with Orfelia and known from a single species from caves in Malaysia, is formally transferred to the Keroplatini. This is the first description of the larva and of the general biology of the genus. The larva of this new species is suspended in a roughly horizontal hammock of silken threads amidst mucous coated snare threads from the roof of caves, but is not bioluminescent as some species of other genera in Keroplatidae ( e. g., Arachnocampa, Keroplatus, and Orfelia). A key to separate both species of the genus is provided. The position of the genus within the Keroplatini is considered. Chetoneura is considered to be closely related to a clade containing Heteropterna and Ctenoceridion.

The look of royalty: visual and odour signals of reproductive status in a paper wasp

Reproductive conflicts within animal societies occur when all females can potentially reproduce. In social insects, these conflicts are regulated largely by behaviour and chemical signalling. There is evidence that presence of signals, which provide direct information about the quality of the reproductive females would increase the fitness of all parties. In this study, we present an association between visual and chemical signals in the paper wasp Polistes satan. Our results showed that in nest-founding phase colonies, variation of visual signals is linked to relative fertility, while chemical signals are related to dominance status. In addition, experiments revealed that higher hierarchical positions were occupied by subordinates with distinct proportions of cuticular hydrocarbons and distinct visual marks. Therefore, these wasps present cues that convey reliable information of their reproductive status.

Regulation by the exogenous polyamine spermidine of Na,K-ATPase activity from the gills of the euryhaline swimming crab Callinectes danae (Brachyura, Portunidae)

Euryhaline crustaceans rarely hyporegulates and employ the driving force of the Na,K-ATPase, located at the basal surface of the gill epithelium, to maintain their hemolymph osmolality within a range compatible with cell function during hyper-regulation. Since polyamine levels increase during the adaptation of crustaceans to hyperosmotic media, we investigate the effect of exogenous polyamines on Na,K-ATPase activity in the posterior gills of Callinectes danae, a euryhaline swimming crab. Polyamine inhibition was dependent on cation concentration, charge and size in the following order: spermine > spermidine > putrescine. Spermidine affected K-0.5 values for Na+ with minor alterations in K-0.5 values for K+ and N-H-4(+), causing a decrease in maximal velocities under saturating Na+, K+ and NH4+ concentrations. Phosphorylation measurements in the presence of 20 mu M ATP revealed that the Na,K-ATPase possesses a high affinity site for this substrate. In the presence of 10 mM Na+, both spermidine and spermine inhibited formation of the phosphoenzyme; however, in the presence of 100 mM Na+, the addition of these polyamines allowed accumulation of the phosphoenzyme. The polyamines inhibited pumping activity, both by competing with Na+ at the Na+-binding site, and by inhibiting enzyme dephosphorylation. These findings suggest that polyamine-induced inhibition of Na,K-ATPase activity may be physiologically relevant during migration to fully marine environments. (c) 2008 Elsevier Inc. All rights reserved.

Potential of Amaranthus cruentus BRS Alegria in the production of flour, starch and protein concentrate: chemical, thermal and rheological characterization

BACKGROUND: Amaranth is a little-known culture in Brazilian agriculture. Amaranthus cruentus BRS Alegria was the first cultivar recommended by Embrapa for the soil of the Brazilian scrubland. In order to evaluate the potential of this species in the production of flour, starch and protein concentrates, the latter products were obtained from A. cruentus BRS Alegria seeds, characterized and compared with the products obtained from the A. caudatus species cultivated in its soil of origin. RESULTS: The seeds of A. cruentus BRS Alegria furnished high-purity starch and flour with significant content of starch, proteins, and lipids. The starch and flour of this species presented higher gelatinization temperatures and formed stronger gels upon cooling compared with those obtained from the A. caudatus species. This is due to their greater amylose content and a difference in the composition of the more important fatty acids, such as stearic, oleic and linoleic acids, which indicates that they have greater heat stability. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and differential scanning calorimetry revealed the presence of albumins, globulins, glutelins and prolamins in the protein concentrate, which was obtained as a byproduct of starch production. CONCLUSION: Amaranthus cruentus BRS Alegria has potential application in the production of flour, starch and protein concentrates, with interesting characteristics for use as food ingredients. (C) 2010 Society of Chemical Industry

Brood production increases when artificial heating is provided to colonies of stingless bees

Although stingless bees are capable of maintaining their nest temperature within certain limits, brood production of several species declines or even completely stops during periods of low ambient temperature. In the present study, we investigated whether the brood production of the meliponine species Nannotrigona testaceicornis can be artificially increased through heating the colonies during the cold season. For this, we monitored the rate of brood cell production of seven hives in intervals of 24 hours under two different experimental conditions: 1. without; and 2. with heating. Each treatment (first with and subsequently without heating) lasted for nine consecutive days. The ambient temperature (TA) during both experimental periods was very similar (TA(WITH) = 16.1 degrees C; TA(WITHOUT) = 16.3 degrees C). On average, the colonies built 3.6 brood cells per day without and 15.8 brood cells per day with artificial heating (Wilcoxon Rank Sum test: T = 10, Z = 4, P < 0.001). In both treatments, the rate of brood cell production increased with increasing environmental temperature (Spearman Rank Correlation: R(WITH) = 0.71, P = 0.02; R(WITHOUT) = 0.66, P = 0.05). We concluded that artificial heating during cold periods increased the brood cell production in N. testaceicornis Our results indicate that the use of heaters for stingless bee hives during periods of low ambient temperature may be helpful for stingless beekeeping.

Immunohistochemistry and polymerase chain reaction on paraffin-embedded material improve the diagnosis of cutaneous leishmaniasis in the Amazon region

Background Recently, there has been an increase in the incidence of cutaneous leishmaniasis (CL), which represents an important health problem. This increase may be related to the epidemiologic expansion of the infective agent and the increase in tourism in tropical areas. The difficulty in clinical diagnosis, mainly in areas in which CL is not the first consideration of local physicians, has intensified efforts to describe diagnostic tests, which should be specific, sensitive, and practical. Amongst the new tests described are those including nucleic acid amplification (polymerase chain reaction, PCR) and immunohistochemistry (IHC). Methods In this study, we evaluated the sensitivity of a PCR based on small subunit (SSU) ribosomal DNA, in comparison with IHC using Leishmania spp. antibodies, in biopsies embedded in paraffin. Result The results indicated a total sensitivity of 96% (90.9% with PCR and 68.8% with IHC), showing the possibility of using paraffin-embedded biopsies to diagnose CL. Conclusion We propose the use of the two tests together as a routine protocol for diagnosis. This would require the provision of local medical services to perform molecular biology techniques and adequate Leishmania antibodies.