Efeito do fator cavitário na resistência adesiva à dentina de um sistema restaurador à base de silorano

O objetivo deste estudo foi avaliar o efeito do fator C na resistência adesiva à dentina humana de um compósito à base de silorano, comparando-o com um compósito à base de metacrilato. Foram utilizados 40 molares humanos hígidos. Em metade da amostra foi realizado um preparo do tipo Classe I, com dimensões de 4x4 mm e 2 mm de profundidade, enquanto na outra metade foi realizado um preparo virtual (flat) com auxílio de uma matriz de teflon branco, com as mesmas dimensões da cavidade (4x4x2 mm), apoiada na superfície de dentina exposta. Cada grupo foi divido em dois, de acordo com o sistema restaurador: Sistema Adesivo P90 e resina Filtek P90; Adper Scotchbond Multiuso e resina Filtek Z350 XT (3M ESPE). Após a aplicação do sistema adesivo segundo as especificações do fabricante, as cavidades (real e virtual) foram preenchidas com as resinas (Z350 XT e P90) em dois incrementos. Foi realizada a fotoativação de cada incremento durante 25s. Após uma semana, as coroas foram seccionadas, obtendo-se espécimes constituídos de resina/dente na forma de um paralelepípedo (palitos). Estes palitos foram utilizados para o teste de microtração (Emic), onde a resistência adesiva na unidade MPa foi calculada. Os resultados foram avaliados estatisticamente pelo teste de análise de variância ANOVA One-Way (p = 0,05), e pelo teste de múltiplas comparações Student Newman Keuls. Foi observada uma diferença estatística entre a resina P90 (flat= 16,137,7 MPa e Cavidade= 16,759,0 MPa) e a Z350 XT (flat= 25,8211,6 MPa e Cavidade=24,4713,5 MPa), independentemente do tipo de cavidade restaurada. E não foi possível observar diferença estatística entre os tipos de cavidades (real ou virtual) restauradas com a mesma resina. Através dos testes realizados, foi possível concluir que: o fator C não afetou a resistência adesiva dos dois sistemas restauradores utilizados, e o tipo de sistema restaurador afeta a resistência adesiva, sendo que o sistema à base de silorano apresenta resultados inferiores ao de metacrilato.

High-resolution natural recording systems: intercomparisons of the response to interannual climatic variability [abstract]

The goal of this work is to examine the properties of recording mechanisms which are common to continuously recording high-resolution natural systems in which climatic signals are imprinted and preserved as proxy records. These systems produce seasonal structures as an indirect response to climatic variability over the annual cycle. We compare the proxy records from four different high-resolution systems: the Quelccaya ice cap of the Peruvian Andes; composite tree ring growth from southern California and the southwestern United States; and the marine varve sedimentation systems in the Santa Barbara basin (off California, United States) and in the Gulf of California, Mexico. An important focus of this work is to indicate how the interannual climatic signal is recorded in a variety of different natural systems with vastly different recording mechanisms and widely separated in space. These high-resolution records are the products of natural processes which should be comparable, to some degree, to human-engineered systems developed to transmit and record physical quantities. We therefore present a simple analogy of a data recording system as a heuristic model to provide some unifying concepts with which we may better understand the formation of the records. This analogy assumes special significance when we consider that natural proxy records are the principal means to extend our knowledge of climatic variability into the past, beyond the limits of instrumentally recorded data.

Plankton indicators and ocean observing systems: support to the marine ecosystem state assessment

Ecological indicators are used extensively as tools to manage environmental resources. In the oceans, indicators of plankton can be measured using a variety of observing systems including: mooring stations, ships, autonomous floats and ocean colour remote sensing. Given the broad range of temporal and spatial sampling resolutions of these different observing systems, as well as discrepancies in measurements obtained from different sensors, the estimation and interpretation of plankton indicators can present significant challenges. To provide support to the assessment of the state of the marine ecosystem, we propose a suite of plankton indicators and subsequently classify them in an ecological framework that characterizes key attributes of the ecosystem. We present two case studies dealing with plankton indicators of biomass, size structure and phenology, estimated using the most spatially extensive and longest in situ and remote-sensing observations. Discussion of these studies illustrates how some of the challenges in estimating and interpreting plankton indicators may be addressed by using for example relative measurement thresholds, interpolation procedures and delineation of biogeochemical provinces. We demonstrate that one of the benefits attained, when analyzing a suite of plankton indicators classified in an ecological framework, is the elucidation of non-trivial changes in composition, structure and functioning of the marine ecosystem.

Androgens and Mating Systems in Fish: Intra- and Inter-specific Analysis

One of the predictions of the ‘challenge hypothesis’ (Wingfield et al., 1990) is that androgen patterns during the breeding season should vary among species according to the parenting and mating system. Here we assess this prediction of the challenge hypothesis both at the intra- and at the inter-specific level. To test the hypothesis at the inter-specific level, a literature survey on published androgen pat- terns from teleost fish with different mating systems was carried out. The results confirm the predicted effect of mating system on andro- gen levels. To test the hypothesis at an intra-specific level, a species with flexible reproductive strategies (i.e. monogamy vs. polygyny), the Saint Peter’s fish was studied. Polygynous males had higher 11- ketotestosterone levels. However, males implanted with methyl-tes- tosterone did not became polygynous and the variation of the ten- dency to desert their pair mates was better explained by the repro- ductive state of the female partner. This result stresses the point that the effects of behaviour on hormones cannot be considered without respect to the social context.

Detection of quasi-periodic processes in complex systems: how do we quantitatively describe their properties?

It has been shown that in reality at least two general scenarios of data structuring are possible: (a) a self-similar (SS) scenario when the measured data form an SS structure and (b) a quasi-periodic (QP) scenario when the repeated (strongly correlated) data form random sequences that are almost periodic with respect to each other. In the second case it becomes possible to describe their behavior and express a part of their randomness quantitatively in terms of the deterministic amplitude–frequency response belonging to the generalized Prony spectrum. This possibility allows us to re-examine the conventional concept of measurements and opens a new way for the description of a wide set of different data. In particular, it concerns different complex systems when the ‘best-fit’ model pretending to be the description of the data measured is absent but the barest necessity of description of these data in terms of the reduced number of quantitative parameters exists. The possibilities of the proposed approach and detection algorithm of the QP processes were demonstrated on actual data: spectroscopic data recorded for pure water and acoustic data for a test hole. The suggested methodology allows revising the accepted classification of different incommensurable and self-affine spatial structures and finding accurate interpretation of the generalized Prony spectroscopy that includes the Fourier spectroscopy as a partial case.

Comparative study about heating systems for pultrusion process

Different heating systems have been used in pultrusion, where the most widely used heaters are planar resistances. The primary objective of this study was to develop an improved heating system and compare its performance with that of a system with planar resistances. In this study, thermography was used to better understand the temperature profile along the die. Finite element analysis was performed to determine the amount of energy consumed by the heating systems. Improvements were made to the die to test the new heating system, and it was found that the new system reduced the setup time and energy consumption by approximately 57%.

Studies on vibrio spp. in juveniles of penaeus indicus in culture systems

The present study is carried out to understand (i) the incidence and occurrence of species of Vibrio in different culture systems in and around Cochin, (ii) characteristics of vibrios isolates, their ecology including growth response to various hydrological parameters, sensitivity to about 40 antibiotics, and (iii) role of physico-chemical parameters in pathogenicity of vibrios, etc. and the results emerged from the investigations are important and encouraging for better understanding of the 'vibriosis' in the culture systems to develop remedial measures to control diseases. The Thesis begins with an “Introduction” followed by “A review of literature” on diseases of penaeid shrimps with particular reference to 'vibriosis' and “Material and methods” which details with the methods and procedures followed in the experiments and analyses of data. This Thesis consists of three chapters. Chapter Ideals with the incidence and ecology of Vibrio spp. in water, sediment and in juveniles of the Indian white prawn Penaeus indicus in the culture systems. In Chapter 2, characteristics of vibrio isolates including growth response to various levels oftemperature, salinity and pl 1, sensitivity to 40 antibiotics and minimal inhibitory concentration tests are detailed.e out-breaks. The Chapter 3 discusses the role of physico-chemical parameters in the incidence, seasonal abundance of Vibrio spp. and in 'vibriosis'. A summary of the whole work and list of references are also included at the end. This study gives a detailed information regarding the incidence and ecology of vibrios in the culture systems. their characteristics and pathogenicity

Studies on the effect of randoniness on the synchronization of coupled systems and on the dynamics of intermittently driven systems

It has been shown recently that systems driven with random pulses show the signature of chaos ,even without non linear dynamics.This shows that the relation between randomness and chaos is much closer than it was understood earlier .The effect of random perturbations on synchronization can be also different. In some cases identical random perturbations acting on two different chaotic systems induce synchronizations. However most commonly ,the effect of random fluctuations on the synchronizations of chaotic system is to destroy synchronization. This thesis deals with the effect of random fluctuations with its associated characteristic timescales on chaos and synchronization. The author tries to unearth yet another manifestation of randomness on chaos and sychroniztion. This thesis is organized into six chapters.

Nitrogen budgets for three cropping systems fertilised with cattle manure

A field plot experiment was set up on a sandy loam soil of SW England in order to determine the efficiency of nitrogen use from different cattle manures. The manure treatments were low and high dry matter cattle slurries and one farmyard manure applied at a target rate of 200 kg total Nha(-1) year(-1), and an untreated control. There were three different cropping systems: ryegrass/clover mixture, maize/rye and maize/bare soil, which were evaluated during 1998/99 and 1999/00. Measurements were made of N losses, N uptake and herbage DM yields. Result showed that manure type had a significant effect on N utilisation only for maize. N balances were negative in maize (approximately -247 to -10 kg N) compared to grass (approximately 5-158 kg N). Agronomic management was more important than manure type in influencing N losses, where soil cultivation appeared to be a key factor when comparing maize and grass systems. (C) 2004 Elsevier Ltd. All rights reserved.

Comparing rice production systems: A challenge for agronomic research and for the dissemination of knowledge-intensive farming practices

This article is a commentary on several research studies conducted on the prospects for aerobic rice production systems that aim at reducing the demand for irrigation water which in certain major rice producing areas of the world is becoming increasingly scarce. The research studies considered, as reported in published articles mainly under the aegis of the International Rice Research Institute (IRRI), have a narrow scope in that they test only 3 or 4 rice varieties under different soil moisture treatments obtained with controlled irrigation, but with other agronomic factors of production held as constant. Consequently, these studies do not permit an assessment of the interactions among agronomic factors that will be of critical significance to the performance of any production system. Varying the production factor of "water" will seriously affect also the levels of the other factors required to optimise the performance of a production system. The major weakness in the studies analysed in this article originates from not taking account of the interactions between experimental and non-experimental factors involved in the comparisons between different production systems. This applies to the experimental field design used for the research studies as well as to the subsequent statistical analyses of the results. The existence of such interactions is a serious complicating element that makes meaningful comparisons between different crop production systems difficult. Consequently, the data and conclusions drawn from such research readily become biased towards proposing standardised solutions for possible introduction to farmers through a linear technology transfer process. Yet, the variability and diversity encountered in the real-world farming environment demand more flexible solutions and approaches in the dissemination of knowledge-intensive production practices through "experiential learning" types of processes, such as those employed by farmer field schools. This article illustrates, based on expertise of the 'system of rice intensification' (SRI), that several cost-effective and environment-friendly agronomic solutions to reduce the demand for irrigation water, other than the asserted need for the introduction of new cultivars, are feasible. Further, these agronomic Solutions can offer immediate benefits of reduced water requirements and increased net returns that Would be readily accessible to a wide range of rice producers, particularly the resource poor smallholders. (C) 2009 Elsevier B.V. All rights reserved.

Diverse signalling by different chemokines through the chemokine receptor CCR5

We have investigated the signalling properties of the chemokine receptor, CCR5, using several assays for agonism: stimulation of changes in intracellular Ca2+ or CCR5 internalisation in CHO cells expressing CCR5 or stimulation of [S-35]GTP gamma S binding in membranes of CHO cells expressing CCR5. Four isoforms of the chemokine CCL3 with different amino termini (CCL3, CCL3(2-70), CCL3(5-70), CCL3L1) were tested in these assays in order to probe structure/activity relationships. Each isoform exhibited agonism. The pattern of agonism (potency, maximal effect) was different in the three assays, although the rank order was the same with CCL3L1 being the most potent and efficacious. The data show that the amino terminus of the chemokine is important for signalling. A proline at position 2 (CCL3L1) provides for high potency and efficacy but the isoform with a serine at position 2 (CCL3(2-70)) is as efficacious in some assays showing that the proline is not the only determinant of high efficacy. We also increased the sensitivity of CCR5 signalling by treating cells with sodium butyrate, thus increasing the receptor/G protein ratio. This allowed the detection of a change in intracellular Ca2+ after treatment with CCL7 and Met-RANTES showing that these ligands possess measurable but low efficacy. This study therefore shows that sodium butyrate treatment increases the sensitivity of signalling assays and enables the detection of efficacy in ligands previously considered as antagonists. The use of different assay systems, therefore, provides different estimates of efficacy for some ligands at this receptor. (c) 2006 Elsevier Inc. All rights reserved.

The air distribution index as an indicator for energy consumption and performance of ventilation systems

This paper deals with the energy consumption and the evaluation of the performance of air supply systems for a ventilated room involving high- and low-level supplies. The energy performance assessment is based on the airflow rate, which is related to the fan power consumption by achieving the same environmental quality performance for each case. Four different ventilation systems are considered: wall displacement ventilation, confluent jets ventilation, impinging jet ventilation and a high level mixing ventilation system. The ventilation performance of these systems will be examined by means of achieving the same Air Distribution Index (ADI) for different cases. The widely used high-level supplies require much more fan power than those for low-level supplies for achieving the same value of ADI. In addition, the supply velocity, hence the supply dynamic pressure, for a high-level supply is much larger than for low-level supplies. This further increases the power consumption for high-level supply systems. The paper considers these factors and attempts to provide some guidelines on the difference in the energy consumption associated with high and low level air supply systems. This will be useful information for designers and to the authors' knowledge there is a lack of information available in the literature on this area of room air distribution. The energy performance of the above-mentioned ventilation systems has been evaluated on the basis of the fan power consumed which is related to the airflow rate required to provide equivalent indoor environment. The Air Distribution Index (ADI) is used to evaluate the indoor environment produced in the room by the ventilation strategy being used. The results reveal that mixing ventilation requires the highest fan power and the confluent jets ventilation needs the lowest fan power in order to achieve nearly the same value of ADI.

Diverse signalling by different chemokines through the chemokine receptor CCR5

We have investigated the signalling properties of the chemokine receptor, CCR5, using several assays for agonism: stimulation of changes in intracellular Ca(2+) or CCR5 internalisation in CHO cells expressing CCR5 or stimulation of [(35)S]GTPgammaS binding in membranes of CHO cells expressing CCR5. Four isoforms of the chemokine CCL3 with different amino termini (CCL3, CCL3(2-70), CCL3(5-70), CCL3L1) were tested in these assays in order to probe structure/activity relationships. Each isoform exhibited agonism. The pattern of agonism (potency, maximal effect) was different in the three assays, although the rank order was the same with CCL3L1 being the most potent and efficacious. The data show that the amino terminus of the chemokine is important for signalling. A proline at position 2 (CCL3L1) provides for high potency and efficacy but the isoform with a serine at position 2 (CCL3(2-70)) is as efficacious in some assays showing that the proline is not the only determinant of high efficacy. We also increased the sensitivity of CCR5 signalling by treating cells with sodium butyrate, thus increasing the receptor/G protein ratio. This allowed the detection of a change in intracellular Ca(2+) after treatment with CCL7 and Met-RANTES showing that these ligands possess measurable but low efficacy. This study therefore shows that sodium butyrate treatment increases the sensitivity of signalling assays and enables the detection of efficacy in ligands previously considered as antagonists. The use of different assay systems, therefore, provides different estimates of efficacy for some ligands at this receptor.

Assessing pragmatic interoperability of information systems from a semiotic perspective

Most of studies on interoperability of systems integration focus on technical and semantic levels, but hardly extend investigations on pragmatic level. Our past work has addressed pragmatic interoperability, which is concerned with the relationship between signs and the potential behaviour and intention of responsible agents. We also define the pragmatic interoperability as a level concerning with the aggregation and optimisation of various business processes for achieving intended purposes of different information systems. This paper, as the extension of our previous research, is to propose an assessment method for measuring pragmatic interoperability of information systems. We firstly propose interoperability analysis framework, which is based on the concept of semiosis. We then develop pragmatic interoperability assessment process from two dimensions including six aspects (informal, formal, technical, substantive, communication, and control). We finally illustrate the assessment process in an example.

Should system dynamics be described as a 'hard' or 'deterministic' systems approach?

This paper explores the criticism that system dynamics is a ‘hard’ or ‘deterministic’ systems approach. This criticism is seen to have four interpretations and each is addressed from the perspectives of social theory and systems science. Firstly, system dynamics is shown to offer not prophecies but Popperian predictions. Secondly, it is shown to involve the view that system structure only partially, not fully, determines human behaviour. Thirdly, the field's assumptions are shown not to constitute a grand content theory—though its structural theory and its attachment to the notion of causality in social systems are acknowledged. Finally, system dynamics is shown to be significantly different from systems engineering. The paper concludes that such confusions have arisen partially because of limited communication at the theoretical level from within the system dynamics community but also because of imperfect command of the available literature on the part of external commentators. Improved communication on theoretical issues is encouraged, though it is observed that system dynamics will continue to justify its assumptions primarily from the point of view of practical problem solving. The answer to the question in the paper's title is therefore: on balance, no.