A análise por injeção sequencial (SIA): vinte anos em uma perspectiva brasileira

The year of 2010 marks the 20th anniversary of the development of Sequential Injection Analysis (SIA) by Ruzicka and Marshall. Considered the second generation of the flow injection methods, this article briefly describes the history, the basic principles of the technique and reviews all papers developed by Brazilian scientists aiming the divulgation of this automation technique in Analytical Chemistry.

Utilização de métodos acústicos em estudos de dinâmica costeira: exemplo na desembocadura lagunar de cananéia

Em função de suas condições de interface entre águas doces e salinas, desembocaduras estuarinas e lagunares constituem sistemas geomorfológicos altamente complexos e dinâmicos. Como conseqüência da variabilidade espacial e temporal dos fluxos de maré, o leito responde com uma grande variabilidade nas características morfológicas e sedimentares. Neste sentido, é possível relacionar diretamente a circulação de fundo e o transporte sedimentar com as feições submersas geradas. Perfis de ecossondagem, sonar de varredura lateral e sísmica de alta resolução, executados na desembocadura lagunar de Cananéia, revelaram a existência de uma dinâmica de fundo extremamente complexa, caracterizada por marcas onduladas e ondas de areia de alturas métricas. As maiores ondas de areia, localizadas em uma depressão na desembocadura lagunar, apresentam inversão de polaridade em sua assimetria, com a presença de ondas simétricas de grande tamanho no ponto de inversão. Este padrão morfológico não apresenta variação temporal em escala anual, sugerindo a persistência de um padrão de fluxos sobre o leito. Esta dinâmica revela, também, a constância de fluxos convergentes que aparentemente independem das condições de maré enchente ou vazante. Os resultados permitiram o estabelecimento de um primeiro modelo qualitativo de circulação de fundo na área, com aplicações potenciais na navegação e estudos de proteção da costa.

Gross anatomical features of the oropharyngeal cavity of the ostrich (Struthio camelus)

Most descriptions of the ostrich oropharynx and oesophagus are superficial and supply little meaningful morphological data. The aim of this investigation is describe the ostrich oropharingeal cavity, in order to supply the deficiency of macroscopic data about this important animal. Five heads of 12 to 14-month-old ostriches of either sex were anatomically dissected to expose the oropharynx. The ostrich oropharynx was "bell-shaped" composed by the maxillary and mandibular ramphoteca. The roof and floor presented two distinct regions different in colour of the mucosa. The rostral region was pale pink contrasting to creamy-pink coloured caudal region. The median longitudinal ridge extended rostrally from the apex of the choana to the tip of the beak in the roof and it is clearly more prominent and rigid than the homolog in the floor that appeared thin and stretched rostrally, continuing caudally surrounding the tongue and the laryngeal mound eventually merging with the oesophageal mucosa. The floor was formed by the interramal region, tongue and laryngeal mound containing shield-shaped glottis. It can be concluded that the present study, in addition to confirming the basic features of the oropharynx previously described for the ostrich, clarified the contradictory information presented in the literature and also provided new, unreported morphological data, some of which may be important when studying nutrition and health in these birds.

Measurement of banana green life

Introduction. This protocol aims at measuring the storage life potential of banana fruit, and at determining the physiological age of fruit. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required laboratory materials and the five steps necessary for calculating the banana green life duration, which corresponds to the number of days between the fruit harvest and climacteric crisis. Results. The measurement of O-2 and CO2 concentrations allows one to detect the climacteric peak which marks the end of the banana green life.

Immunological Basis for the Gender Differences in Murine Paracoccidioides brasiliensis Infection

This study aimed to investigate the immunological mechanisms involved in the gender distinct incidence of paracoccidioidomycosis (pcm), an endemic systemic mycosis in Latin America, which is at least 10 times more frequent in men than in women. Then, we compared the immune response of male and female mice to Paracoccidioides brasiliensis infection, as well as the influence in the gender differences exerted by paracoccin, a P. brasiliensis component with carbohydrate recognition property. High production of Th1 cytokines and T-bet expression have been detected in the paracoccin stimulated cultures of spleen cells from infected female mice. In contrast, in similar experimental conditions, cells from infected males produced higher levels of the Th2 cytokines and expressed GATA-3. Macrophages from male and female mice when stimulated with paracoccin displayed similar phagocytic capability, while fungicidal activity was two times more efficiently performed by macrophages from female mice, a fact that was associated with 50% higher levels of nitric oxide production. In order to evaluate the role of sexual hormones in the observed gender distinction, we have utilized mice that have been submitted to gonadectomy followed by inverse hormonal reconstitution. Spleen cells derived from castrated males reconstituted with estradiol have produced higher levels of IFN-gamma (1291+/-15 pg/mL) and lower levels of IL-10 (494+/-38 pg/mL), than normal male in response to paracoccin stimulus. In contrast, spleen cells from castrated female mice that had been treated with testosterone produced more IL-10 (1284+/-36 pg/mL) and less IFN-gamma (587614 pg/mL) than cells from normal female. In conclusion, our results reveal that the sexual hormones had a profound effect on the biology of immune cells, and estradiol favours protective responses to P. brasiliensis infection. In addition, fungal components, such as paracoccin, may provide additional support to the gender dimorphic immunity that marks P. brasiliensis infection.

Observation of cooperative Mie scattering from an ultracold atomic cloud

Scattering of light at a distribution of scatterers is an intrinsically cooperative process, which means that the scattering rate and the angular distribution of the scattered light are essentially governed by bulk properties of the distribution, such as its size, shape, and density, although local disorder and density fluctuations may have an important impact on the cooperativity. Via measurements of the radiation pressure force exerted by a far-detuned laser beam on a very small and dense cloud of ultracold atoms, we are able to identify the respective roles of superradiant acceleration of the scattering rate and of Mie scattering in the cooperative process. They lead, respectively, to a suppression or an enhancement of the radiation pressure force. We observe a maximum in the radiation pressure force as a function of the phase shift induced in the incident laser beam by the cloud's refractive index. The maximum marks the borderline of the validity of the Rayleigh-Debye-Gans approximation from a regime, where Mie scattering is more complex. Our observations thus help to clarify the intricate relationship between Rayleigh scattering of light at a coarse-grained ensemble of individual scatterers and Mie scattering at the bulk density distribution.

Failure analysis of belt/roll tribological pair used for the production of eucalypt fiber panels

The premature failure of a large agglomeration machine used for the annual production of 360,000 m(3) of eucalypt fiber panels was investigated to identify the nucleation and growth mechanisms of cracking in PH stainless steel belts (126 m x 2.9 m x 3.0 mm). These belts are used to compress a cushion composed of eucalyptus fibers and glue, being the pressure transmitted from the pistons by the action of numerous case-hardening steel rolls. Examination of the belt working interfaces (belt/rolls and belt/eucalypt fibers) indicated that the main cracking was nucleated on the belt/roll interface and that there is a clear relationship between the crack nucleation and the presence of superficial irregularities, which were observed on the belt/roll working surface. Used rolls showed the presence of perimetric wear marks and 2 mu m silicon-rich encrusted particles (identified as silicon carbide). Lubricant residues contained the presence of helicoidal wires, which were originated by the release of the stainless steel cleaning brush bristles, and 15 mu m diameter metallic particles, which were generated by material detachment of the belt. The presence of foreign particles on the tribological interface contributed to an increase of the shear stresses at the surfaces and, consequently, the number of the contact fatigue crack nucleation sites in the belt/roll tribo-interface. The cracking was originated on the belt/roll interface of the stainless steel belt by a mixed rolling/slip contact fatigue mechanism, which promoted spalling and further nucleation and growth of conventional fatigue cracks. Finally, the system lubrication efficiency and the cleaning procedure should be optimised in order to increase the life expectancy of the belt. (c) 2006 Elsevier Ltd. All rights reserved.

Bending fatigue of stainless steel shear pins belonging to a hydroelectric plant

Coaracy Nunes was the first hydroelectric power plant in the Amazon region, being located in Araguari River, Amapa State, Brazil. The plant operates since 1976, presenting now a nominal capacity of 78 MW. The shear pins, which are installed in the turbine hydraulic arms to control the wicket gate and regulate the water flow into the turbine blades, suffered several breakdowns since 2004. These shear pins are made of an ASTM 410 stainless steel and were designed to break by a shear overload of 120 kN. Fractographic investigation of the pins, however, revealed two types of fracture topographies: a region of stable crack propagation area, with non-pronounced striation and secondary cracks; and a region of unstable propagation, featuring elongated dimples. These results indicated that the stable crack propagation occurred by fatigue (bidirectional bending), which was nucleated at machining marks under high nominal load. Finite element analysis was carried out using two loading conditions (pure shear and a combination of shear and bending) and the results indicated that the presence of a bending stress strongly increased the stress concentration factor (85% rise in the shear stress and 130% rise in the Von Mises stress). Misalignment during shear pins assembly associated with vibration might have promoted the premature failure of the shear by bending fatigue. (C) 2008 Elsevier Ltd. All rights reserved.

Cracking of 2.25Cr-1.0Mo steel tube/stationary tube-sheet weldment of a heat-exchanger

The premature failure of a horizontal heat-exchanger, which occurred after service exposure at 580 degrees C for 50,000 h, revealed the occurrence of extensive through-thickness cracking in approximately 40% of the tube/stationary tube-sheet welds. Additionally, the internal surface of the welded joint featured intensive secondary intergranular cracking (up to 250 mu m deep), preferential formation of a 150 mu m thick layer of (Fe, Cr)(3)O-4 and internal intergranular oxidation (40 mu m deep). The welded region also showed intense carbon pick-up and, as consequence, severe precipitation of intergranular M7C3 and M23C6 carbides. The fracture surface was composed of two distinct regions: a ""planar"" region of 250 mu m, formed due to the stable crack growth along by the intergranular oxidation; and a slant region with radial marks, formed by the fast crack growth along the network of intergranular carbides. The association of intergranular oxidation pre-cracks with microstructural embrittlement promoted the premature failure, which took place by an overload mechanism, probably due to the jamming of the floating tube-sheet during the maintenance halt (cooling operation). (C) 2007 Elsevier Ltd. All rights reserved.

Olfactory eavesdropping between two competing stingless bee species

Foragers can improve search efficiency, and ultimately fitness, by using social information: cues and signals produced by other animals that indicate food location or quality. Social information use has been well studied in predator-prey systems, but its functioning within a trophic level remains poorly understood. Eavesdropping, use of signals by unintended recipients, is of particular interest because eavesdroppers may exert selective pressure on signaling systems. We provide the most complete study to date of eavesdropping between two competing social insect species by determining the glandular source and composition of a recruitment pheromone, and by examining reciprocal heterospecific responses to this signal. We tested eavesdropping between Trigona hyalinata and Trigona spinipes, two stingless bee species that compete for floral resources, exhibit a clear dominance hierarchy and recruit nestmates to high-quality food sources via pheromone trails. Gas chromatography-mass spectrometry of T. hyalinata recruitment pheromone revealed six carboxylic esters, the most common of which is octyl octanoate, the major component of T. spinipes recruitment pheromone. We demonstrate heterospecific detection of recruitment pheromones, which can influence heterospecific and conspecific scout orientation. Unexpectedly, the dominant T. hyalinata avoided T. spinipes pheromone in preference tests, while the subordinate T. spinipes showed neither attraction to nor avoidance of T. hyalinata pheromone. We suggest that stingless bees may seek to avoid conflict through their eavesdropping behavior, incorporating expected costs associated with a choice into the decision-making process.

La Pointe Saint Mathieu, Brittany, France

The "Pointe Saint Mathieu" is one of the most westerly continental landmarks of France. The promontory is located at the entrance of the "Goulet de la Rade de Brest", that is the entrance channel of the harbour of Brest in Brittany (France). It marks also the Southern end of the "Chenal du Four" that is the main navigation channel between the islands of Ouessant, Molène and Béniquet, and Brittany. The "Chenal du Four" is reputed for its dangers. The tidal range is greater than 7 m in spring tides, and the mid-tide current may exceed 5 knots. The Saint Mathieu promontory is equipped with a lighthouse and a semaphore. The former is located in the ruins of an old monastery, founded during the 6th century AD by Saint Tanguy. The present ruins are the remnants of buildings from the 11th to 15th centuries. The first lighthouse was installed in 1689, although the monks of the monastery used to maintain a signal light since the 1250s. Completed in 1835, the present "Phare de la Pointe Saint-Mathieu" is 37 m high and it reaches 58.8 m above sea level During World War 2, the Pointe Saint Mathieu was defended by a series of concrete fortifications built by the Germans. Some were based upon some earlier French bunker systems, like the coastal battery at the Rospects which included 4 main gun bunkers (4*150 mm, or 2*150 mm & 2*105 mm), an observation bunker on the Western side close to sea, and several smaller structures. There was also the large Kéringar Blockhaus system, near Lochrist, located about 1 km inland and designed for 4 guns of 280 mm. Its command bunker remains a landmark along the main road. All this area was very-heavily bombed between 1943 and 1944, and particularly during the battle of Brest in August-September 1944 ("L'Enfer de Brest").

Liquid distribution as a means to describing the granule growth mechanism

Copper concentrate (chalcopyrite) was granulated in a rotating drum with a diameter of 0.3 m and a length of 0.2 m. Water was used as the binder and it was sprayed onto the powder bed with a nozzle. This material exhibited induction type behaviour, which was defined by Iveson and Litster [AIChE J. 44 (1998) 1510]. Induction type behaviour is characterized by the occurrence of an induction stage, during which the granules are gradually being compacted and little or no growth occurs. At the end of this induction stage, binder liquid is squeezed from the interior of the granules onto the granule surface and the granules are then surface-wet. This results in a rapid growth rate of the granules. Different types of experiments were conducted. The influence of the nozzle pressure and the distance from the nozzle to the powder bed on the growth behaviour of the granules as well as on the binder distribution was examined. The results of these experiments led to the postulation of a modified mechanism for induction type behaviour: it was found that after the binder was delivered, there were large granules containing a high amount of binder and small granules containing less binder. During the induction stage, the granules are compacted and binder liquid continuously appears at the surface of the large granules. These wet spots that are continuously being formed pick up the dry and small granules. When all the small granules have been picked up, further expulsion of binder liquid onto the granules' surface results in granules that remain surface-wet. This phenomenon marks the end of the induction stage and it coincides with the disappearance of the small granules. The hypothesis was tested by selectively removing the smaller granules during an experiment. As expected, this resulted in a shorter induction time.

Australia’s Lily Brayton: Performer and theatre artist

Recognition is the aim of this account of an artist who is now remembered largely for her beauty, her wide iconic fame achieved by mass distribution of her image via photography and postcards, and her professional association with a internationally prominent producer who was also her husband. It is however a historically situated study, confining itself to readings of the kind of theatrical, social and cultural work performed by Brayton's presence in a rapidly-modernising Australia during the period between Federation in 1901 and the first World War, which event marks a disjuncture in the patterns of entertainment and cultural discourse in the new nation. Pre-war Australian theatre and vaudeville managements competed vigorously to secure the most acclaimed artists, seeing it as a kind of service and duty to boost their country's prestige along with their own coffers. Meanwhile, local playwrights and producers promoted a burgeoning repertoire of Australian dramas and films which played alongside the imported products in a complex network of cultural codes and affects.

Formal performance appraisal interviews: Can they really be objective, and are they useful anyway?

This paper reports on a qualitative field study conducted in Australia which examined what is occurring in formal performance appraisal interviews in relation to their objectivity and resultant outcomes. Supervisors and subordinates who had recently been involved in performance appraisals were interviewed about their experiences of the process. Perceptions of the utility of, and satisfaction with the interview process were examined. Further, the effect of the relationship between the participants on objectivity was investigated. Results indicated that formal appraisal interviews were not perceived to be of great utility, and that the relationship of the participants influenced the interview.

The effect of organisational culture perceptions on the relationship between budgetary participation and managerial job-related outcomes

The impact of managers' perceptions of their organizational culture (OC) on the relationship between budgetary participation (BP) and managerial job-related outcomes, operationalized as managerial performance and job-related tension (JRT) is examined. Data supported predictions that increasing BP would lower JRT for managers perceiving a high emphasis on innovation within their OC, regardless of their perceptions of an emphasis on attention to detail. When managers perceived low innovation, however, their perception of level of attention to detail had a significant effect on the relationship between BP and JRT.