Comparison of artificial and natural, new and reused, brackish water for the larviculture of the freshwater prawn Macrobrachium rosenbergii in a recirculating system

Differences in culture duration, metamorphosis rate and the productivity in hatchery culture of M. rosenbergii using a closed system with natural and artificial brackish water were evaluated. Reuse of brackish water in more than one hatchery cycle was also evaluated. Natural and artificial brackish water constituted the two tested treatments, which were distributed in four independent recirculating systems (tank and respective biofilter). Four batches of cultures were conducted and the 2nd and 4th reused the water from the 1st and 3rd, respectively. Mean duration of the hatchery period was 28 d in natural brackish water and 31 d in artificial brackish water. The metamorphosis rate and the average productivity for the natural brackish water treatment were 74% and 60 postlarvae/ L. respectively, and values obtained with artificial brackish water were 55% and 44 postlarvae/L. The successful hatchery culture of M. rosenbergii in this specific artificial brackish water suggests its potential use in enterprises located far from the coast. Brackish water can be used in two consecutive cultures without a negative effect on productivity.

Efeitos de diferentes doses de tenoxicam sobre a medula espinhal e as meninges. Estudo experimental em caes

Background and Objectives. The analgesic actions of nonsteroidal anti-inflammatory drugs (NSAID) result from the inhibition of the peripheral synthesis of prostaglandins. In spite of the emphasis on the peripheral action, several studies have shown the potential central action of such drugs. In rats, NSAID doses insufficient to block pain when systemically administered were effective when intrathecally injected. This effect could be mediated by interaction with descending serotoninergic ways together with neurotransmission modulation of glycine or N-methyl-D-aspartate receptors. Our goal was to study the effect of different tenoxican doses in the histology of dogs spinal cord and meninges. Methods. Thirty two dogs (7 to 17 kg) were randomly distributed in four groups: G1 - Control with distilled water (DW); G2 - 2 mg tenoxican diluted in DW; G3 - 4 mg tenoxican diluted in DW; G4 - 10 mg tenoxican diluted in DW in a constant volume of 1 ml. Anesthesia was induced with etomidate and fentanyl and dural puncture was performed with a 25G spinal needle in interspace L6-7. Animals were observed for 72 hours and subsequently euthanized by electrocution. Lumbar and sacral spinal cord segments were removed for further histologic examination. Results. All animals were clinically normal during the observation period and there has been no histologic alteration of the nervous system and meninges. Conclusions. In our experimental model intrathecal tenoxican doses up to 10 mg have not triggered nervous tissue or meningeal injuries in dogs.

Response of human pulps capped with a self-etching adhesive system

Objective: The aim of this study was to evaluate the human pulp response following direct pulp capping with a current self-etching bonding agent and calcium hydroxide (CH). Methods: Thirty-three sound human premolars had their pulp tissue mechanically exposed. Sterile distilled water was used to control the hemorrhage and exudation from the pulp exposure site. The pulps were capped with Clearfil Liner Bond 2 (CLB-2) or CH and the cavities were filled with a resin composite (Z-100) according to the manufacturer's instructions. After 5, 30 and 120-300 days, the teeth were extracted and processed for microscopic examination. Results: At short-term, CLB-2 elicited a mild to moderate inflammatory pulp response with dilated and congested blood vessels adjacent to pulp exposure site. With time, macrophages and giant cells engulfing globules and particulates of resinous material displaced into the pulp space were observed. This chronic inflammatory pulp response triggered by fragments of bonding agent displaced into the pulp space did not allow pulp repair interfering with the dentin bridging. On the other hand, pulps capped with CH exhibited an initial organization of elongated pulp cells underneath the coagulation necrosis. Pulp repair and complete dentin bridge formation was observed at long-term evaluation. Significance: The present study demonstrated that CH remains the pulp capping agent of choice for mechanically exposed human pulps. CLB-2 did not allow complete connective tissue repair adjacent to the pulp exposure site. Consequently, this bonding agent cannot be recommended for pulp therapy of sound human teeth. © 2001 Academy of Dental Materials. Published by Elsevier Science Ltd. All rights reserved.

Effect of cyclic compressive loading on the bond strength of an adhesive system to dentin after collagen removal

Purpose: The objective of this study was to verify the effect of cyclic compressive loading on the shear bond strength of an adhesive system following collagen removal. Materials and Methods: Sixty bovine teeth were divided into 4 groups based on the adhesive procedure used: groups 1 and 2 - etching with 35% phosphoric acid and application of the Single Bond adhesive system; groups 3 and 4 - after etching, a 10% sodium hypochlorite solution was applied for 1 min before the application of the adhesive. In all the specimens, a Z100 resin cylinder was built up over the bond area. Groups 2 and 4 were submitted to 500,000 cycles with a load of 100 N. Results: The mean values for the shear bond test (MPa) were: group 1: 7.37 ± 1.15; group 2: 5.72 ± 1.66; group 3: 5.95 ± 1.21; group 4: 3.66 ± 1.12. There was no difference between groups 1 and 2 (p > 0.01). Between groups 1 and 3, 2 and 4, and 3 and 4 there was a significant difference (p < 0.01). The majority of the specimens demonstrated an adhesive failure. Conclusion: The application of sodium hypochlorite on dentin decreased the values of shear bond strength, as did the load cycling in the group treated with sodium hypochlorite.

Investigation into the impact of embedded generators on distribution system performance using theorem of superposition

Since the 1980s, huge efforts have been made to utilise renewable energy sources to generate electric power. One of the interesting issues about embedded generators is the question of optimal placement and sizing of the embedded generators. This paper reports an investigation of impact of the integration of embedded generators on the overall performances of the distribution networks in the steady state, using theorem of superposition. Set of distribution system indices is proposed to observe performances of the distribution networks with embedded generators. Results obtained from the case study using IEEE test network are presented and discussed.

The effect of adhesive systems on the pullout strength of a fiberglass-reinforced composite post system in bovine teeth

Purpose: To evaluate the pullout strength of a glass fiber-reinforced composite post (glass FRC) cemented with three different adhesive systems and one resin cement. The null hypothesis was that pullout strengths yielded by the adhesive systems are similar. Materials and Methods: Thirty bovine teeth were selected. The size of the specimens was standardized at 16 mm by sectioning off the coronal portion and part of the root. The specimens were divided into three groups, according to the adhesive system, which were applied following the manufacturers' instructions: G1, ScotchBond Multi-Purpose Plus; G2, Single Bond; G3, Tyrian SPE/One-Step Plus. The glass FRCs (Reforpost) were etched with 37% H3PO4 for 1 min and silanized (Porcelain Primer). Thereafter, they were cemented with the dual resin cement En-Force. The specimens were stored for 24 h, attached to an adapted device, and submitted to the pullout test in a universal testing machine (1 mm/min). The data were submitted to the one-way ANOVA and Tukey's test (α = 0.05). Results: G1 (30.2 ± 5.8 Kgf) displayed the highest pullout strength (p < 0.001) when compared to G2 (18.6 ± 5.8 Kgf) and G3 (14.3 ± 5.8 Kgf), which were statistically similar. Analysis of the specimens revealed that all failures occurred between the adhesive system and the root dentin (pullout of the post cement), regardless of group. Conclusion: The multiple-bottle, total-etch adhesive system provided higher pullout strength of the glass FRC when compared to the single-bottle, total-etch, and single-step self-etching adhesive systems. The null hypothesis was rejected (p < 0.001).

Effect of rotary instrumentation and of the association of calcium hydroxide and chlorhexidine on the antisepsis of the root canal system in dogs

This study aimed at evaluating the antisepsis of the root canal system (RCS) and periapical region (PR) provided by rotary instrumentation associated with chlorhexidine + calcium hydroxide as intracanal medicament. Chronic periapical lesions were induced in 26 pre-molar roots in two dogs. After microbiological sampling, automatic instrumentation using the Profile system and irrigation with 5.25% sodium hypochlorite solution, with a final rinse of 14.3% EDTA followed by profuse irrigation with physiological saline were carried out in 18 root canals. After drying the canals, a paste based on calcium hydroxide associated with a 2% chlorhexidine digluconate solution was placed inside them. After 21 days, the medication was removed, leaving the root canals empty and coronally sealed. After 96 hours, a final microbiological sample was obtained, followed by histomicrobiological processing by the Brown & Brenn method. Eight untreated root canals represented the control group (C-G). Based on the Mann-Whitney test at a confidence level of 5% (p < 0.05), the procedures of antisepsis used offered significant efficacy (p < 0.05) resulting in 100.0% of the canals free of microorganisms. In the C-G, an elevated incidence of various microbial morphotypes was confirmed in all sites of the RCS, with the presence of microbial colonies in the periapical region. In contrast, the experimental group showed a similar pattern of infection in the RCS, although less intense and a reduced level of periapical infection (p < 0.05). It was concluded that adequate instrumentation followed by the application of calcium hydroxide + chlorhexidine offered significant elimination of microorganisms.

A Harris-Todaro agent-based model to rural-urban migration

The Harris-Todaro model of the rural-urban migration process is revisited under an agent-based approach. The migration of the workers is interpreted as a process of social learning by imitation, formalized by a computational model. By simulating this model, we observe a transitional dynamics with continuous growth of the urban fraction of overall population toward an equilibrium. Such an equilibrium is characterized by stabilization of rural-urban expected wages differential (generalized Harris-Todaro equilibrium condition), urban concentration and urban unemployment. These classic results obtained originally by Harris and Todaro are emergent properties of our model.

Chronological Monte Carlo-based assessment of distribution system reliability

Regulatory authorities in many countries, in order to maintain an acceptable balance between appropriate customer service qualities and costs, are introducing a performance-based regulation. These regulations impose penalties, and in some cases rewards, which introduce a component of financial risk to an electric power utility due to the uncertainty associated with preserving a specific level of system reliability. In Brazil, for instance, one of the reliability indices receiving special attention by the utilities is the Maximum Continuous Interruption Duration per customer (MCID). This paper describes a chronological Monte Carlo simulation approach to evaluate probability distributions of reliability indices, including the MCID, and the corresponding penalties. In order to get the desired efficiency, modern computational techniques are used for modeling (UML -Unified Modeling Language) as well as for programming (Object- Oriented Programming). Case studies on a simple distribution network and on real Brazilian distribution systems are presented and discussed. © Copyright KTH 2006.

Support on the remote interaction for augmented reality system

This article presents a support on the remote interaction for utilization in augmented reality systems based on ARToolkit. It utilizes the multicast communication in order to improve the scalability of distributed environment. This support may be utilized in production of specific applications pointed to distance education, training and entertainment. The validity of support happened with the implementation of a prototype and realization of tests for communication latency analysis and frames per second rate. © 2007 IEEE.

A multiagent architecture for supervisory and control system

Supervising and controlling the many processes involved in petroleum production is both dangerous and complex. Herein, we propose a multiagent supervisory and control system for handle continuous processes like those in chemical and petroleum industries In its architeture, there are agents responsible for managing data production and analysis, and also the production equipments. Fuzzy controllers were used as control agents. The application of a fuzzy control system to managing an off-shore installation for petroleum production onto a submarine separation process is described. © 2008 IEEE.

Microbial distribution in the root canal system after periapical lesion induction using different methods

The aim of this study was to evaluate the microbial distribution in the root canal system after periapical lesion induction in dogs' teeth using different methods. Fifty-two root canals were assigned to 4 groups (n=13). Groups I and II: root canals were exposed to the oral cavity for 180 days; groups III and IV: root canals were exposed for 7 days and then the coronal openings were sealed for 53 days. The root apices of groups I and III were perforated, while those of groups II and IV remained intact. After the experimental periods, the animals were euthanized and the anatomic pieces containing the roots were processed and stained with the Brown & Brenn method to assess the presence and distribution of microorganisms. The incidence of microorganisms at different sites of the roots and periapical lesions was analyzed statistically by the chi-square test at 5% significance level. All groups presented microorganisms in the entire root canal system. A larger number of microorganisms was observed on the root canal walls, apical delta and dentinal tubules (p<0.05), followed by cementum and cemental resorption areas. In spite of the different periods of exposure to the oral environment, the methods used for induction of periapical periodontitis yielded similar distribution of microorganisms in the root canal system.

Distributed generation impact evaluation using a multi-objective tabu search

Distribution networks paradigm is changing currently requiring improved methodologies and tools for network analysis and planning. A relevant issue is analyzing the impact of the Distributed Generation penetration in passive networks considering different operation scenarios. Studying DG optimal siting and sizing the planner can identify the network behavior in presence of DG. Many approaches for the optimal DG allocation problem successfully used multi-objective optimization techniques. So this paper contributes to the fundamental stage of multi-objective optimization of finding the Pareto optimal solutions set. It is proposed the application of a Multi-objective Tabu Search and it was verified a better performance comparing to the NSGA-II method. © 2009 IEEE.

Trolleybus power system for operation with AC or DC distribution networks

This paper presents the development and experimental analysis of a special input stage converter for a Trolleybus type vehicle allowing its operation in AC (two wires, single-phase) or DC distribution networks. The architecture of proposed input stage converter is composed by five interleaved boost rectifiers operating in discontinuous conduction mode. Furthermore, due to the power lines characteristics, the proposed input power structure can act as AC to DC or as DC to DC converter providing a proper DC output voltage range required to the DC bus. When operation is AC to DC, the converter is capable to provide high power factor with reduced harmonic distortion for the input current, complying with the restrictions imposed by IEC 61000-3-4 standard. Finally, the main experimental results are presented in order to verify the feasibility of the proposed converter, demonstrating the benefits and the possibility for AC feeding system for trolleybus type vehicle. © 2010 IEEE.

Morphology of collagen fibers and elastic system fibers in actinic cheilitis

Background: Actinic cheilitis (AC) is a premalignant condition intimately related to exposure of the lips to sun rays. Aim: The objective of this study was to evaluate the elastic and collagen fibers in the lamina propria of AC. The degree of epithelial atypia was correlated with the quantity of elastic and collagen fibers. Materials and Methods: Fifty-one cases were investigated. One slide was stained with hematoxylin-eosin for the evaluation of atypia, the second was stained with Weigert′s resorcin-fuchsin for the assessment of elastic fibers, and the third slide was stained with Mallory′s trichrome for the analysis of collagen fibers. Results: Ordinal logistic regression analysis revealed a significant correlation between the presence of atypia and collagen fibers (P<0.05). Conclusions: It was concluded that there seems to be a reduction in the quantity of collagen fibers in cases of moderate and severe atypia. No correlation was observed between the degradation of elastic system fibers and the grade of dysplasia.