Stochastic stability for Markovian jump linear systems associated with a finite number of jump times

This paper deals with a stochastic stability concept for discrete-time Markovian jump linear systems. The random jump parameter is associated to changes between the system operation modes due to failures or repairs, which can be well described by an underlying finite-state Markov chain. In the model studied, a fixed number of failures or repairs is allowed, after which, the system is brought to a halt for maintenance or for replacement. The usual concepts of stochastic stability are related to pure infinite horizon problems, and are not appropriate in this scenario. A new stability concept is introduced, named stochastic tau-stability that is tailored to the present setting. Necessary and sufficient conditions to ensure the stochastic tau-stability are provided, and the almost sure stability concept associated with this class of processes is also addressed. The paper also develops equivalences among second order concepts that parallels the results for infinite horizon problems. (C) 2003 Elsevier B.V. All rights reserved.

Influence of processing parameters on nanomaterials synthesis efficiency by a carbothermal reduction process

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Application times, sources and doses of nitrogen on wheat cultivars under no till in the Cerrado region

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stroke in ancient times - a reinterpretation of Psalms 137 : 5,6

Stroke was probably first described in Psalms 136: 5-6 of the Catholic Bible, and Psalms 137:5-6 of the Evangelical Bible. Based on the Portuguese, Spanish, English, German, Dutch, Russian, Greek, and original Hebrew Bible, the significance of this Psalm is the invocation of a punishment, of which the final result would be a stroke of the left middle cerebral artery, causing motor aphasia and right hemiparesis.

Sexual harassment in Dentistry: prevalence in dental school

Objective: Sexual harassment is unlawful in all work and educational environments in most nations of the world. The goals of this study were to describe the sexual harassment prevalence and to evaluate the experiences and attitudes of undergraduate students in one dental school in Brazil. Material and Methods: An 18-item questionnaire was administered to 254 dental students with a completion rate of 82% (208). Students were requested to respond to questions about their background and academic level in dental school, their personal experiences with sexual harassment and their observation of someone else being sexually harassed. Bivariate statistical analyses were performed. Results: Fifteen percent of the students reported being sexually harassed by a patient, by a relative of a patient or by a professor. Male students had 3 times higher probability of being sexually harassed than female student [OR = 2.910 (1.113-7.611)]. Additionally, 25.4% of the students reported witnessing sexual harassment at the school environment. The majority of students did not feel professionally prepared to respond to unwanted sexual behaviors. Conclusion: These findings demonstrate that sexual harassment can occur in a dental school setting. There is a need for ongoing sexual harassment education programs for students and university staff. Increased knowledge of sexual harassment during graduation can better prepare dental professionals to respond to sexual harassment during their practice.

EFFECT of ULTRASONIC EXCITATION on THE MICROTENSILE BOND STRENGTH of GLASS IONOMER CEMENTS TO DENTIN AFTER DIFFERENT WATER STORAGE TIMES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of alternative photostimulable phosphor plates erasing times on subjective digital image quality

Objective: To evaluate the influence of alternative erasing times of DenOptix (R) (Dentsply/Gendex, Chicargo, IL) digital plates oil subjective image quality and the probability of double exposure image not Occurring.Methods: Human teeth were X-rayed with phosphor plates using tell different erasing times. Two observers evaluated the images for subjective Image quality (sharpness, brightness, contrast, enamel definition, dentin definition and dentin-enamal Junction definition) and for the presence or absence of double exposure image. Spearman's correlation analysis and ANOVA was performed to verify the existence ora linear association between the subjective image quality parameters and the alternative erasing times. A contingency table was constructed to evaluate the agreement among the observers, and a binominal logistic regression was performed to verify the correlation between the erasing time and the probability of double exposure image not occurring.Results: All 6 parameters or image quality were rated high by the examiners for the erasing times between 25 s and 130 s. The same erasing time range, from 25 to 130 s, was considered a safe erasing time interval, with no probability of a double exposure image Occurring.Conclusions: The alternative erasing times from 25 s to 130 s showed high quality and no probability of double image Occurrence. Thus, it is possible to reduce the operating time or the DenOptix (R) digital system Without jeopardizing the diagnostic task.Dentomaxillofacial Radiology (2010) 39, 23-27. doi: 10.1259/dmfr/49065239.

Flexural strength and hardness of reline and denture base acrylic resins after different exposure times of microwave disinfection

Objectives: To evaluate the effect of microwave disinfection on the flexural strength and Vickers hardness of 4 autopolymerized resins (Kooliner [K], Tokuso Rebase Fast [T], Ufi Gel Hard [U], and New Truliner [N]) and 1 denture base resin (Lucitone 550 [L]). Method and Materials: For each material, 48 specimens (64 x 10 x 3.3 mm) were made and divided into 6 equal groups (n = 8). In the control group, specimens were untreated. Before testing, specimens were immersed in 200 mL of distilled water and submitted to disinfection for 1 of the following irradiation times: 1, 2, 3, 4, or 5 minutes. The irradiation procedure was performed twice. The flexural strength was determined using a testing machine MTS-810 and measurements of Vickers hardness were made on Micromet 2100. The values were submitted to ANOVA and Tukey's test (P = .05). Results: The K material showed a significant increase (P = .0010) in flexural strength following 5 minutes of disinfection compared to control specimens. The flexural strength mean values of materials T, U, and N were not significantly affected (P > .05) by disinfection. Compared to the control group, the K material showed a significant increase in hardness (P < .001) following disinfection for 3, 4, and 5 minutes. For material U, disinfection for 4 and 5 minutes produced specimens with significantly increased hardness values (P < .001) compared to the control group. For material N, disinfection for 5 minutes resulted in significantly higher hardness values (P < .001) than the control group. Conclusion: Regardless of the irradiation time, the flexural strength and hardness of the materials evaluated were not detrimentally affected by microwave disinfection. (Quintessence Int 2008;39:833-840)

The influence of initial feeding on muscle development and growth in pacu Piaractus mesopotamicus larvae

The effects of different feeding schemes on pacu Piaractus mesopotamicus early development were evaluated with respect to growth, survival, muscle development, and differential gene expression of MyoD and myogenin. The pacu larvae (4 days post hatch-dph, 0.77 mg wet weight) were given six feeding treatments intentionally designed to cause variations in the larvae growth rate: (A) only artemia nauplii; (CD) only a commercial diet; (ED) only a semi-purified experimental diet; (ACD) and (AED) two treatments that involved weaning; and (S) starvation. Early weaning from artemia nauplii to the formulated diets (ACD and AED) affected growth and survival of the pacu larvae compared with the exclusive use of artemia (A). Starvation (S) and the commercial diet (CD) caused total mortality in pacu larvae at 18 dph. The experimental diet (ED) assured low fish survival and growth. The skeletal muscle morphology was not affected by the delay in somatic growth from early weaning onto the formulated diets. Three distinct muscle compartments were observed throughout the larval development in treatments A, ACD and AED: superficial, deep and intermediate, accompanied by muscle thickening. Severe undernourishment caused drastic differences in growth and in the morphology of the muscle fibers. Pacu larvae fed only formulated diets (CD and ED) showed muscle characteristics similar to the larvae in starvation (S) during the first 15 dph. At 27 and 35 dph, a slight increase in epaxial muscle mass was noted in larvae fed only the experimental diet (ED). At 35 dph, we observed a high frequency of fibers >= 40 mu m in the larvae that were weaned onto the formulated diets (ACD and AED), indicative of hypertrophy. In contrast, the larvae fed only artemia nauplii (A) displayed a larger number of fibers with diameters <= 20 mu m, which is indicative of hyperplasia. The expression of the MyoD and myogenin genes in pacu larvae at 35 dph was not affected by initial feeding (p>0.05). In conclusion, the formulated diets used impaired pacu larvae growth and survival; therefore, they were inadequate for pacu, at least at the times they were introduced. Artemia nauplii were the most adequate food source during first feeding of the pacu, and they produced bigger fish upon completion of the experiment. Moreover, the contribution of hyperplasia to the skeletal muscle growth appeared higher in fast- than in slow-growing pacu larvae. (C) 2011 Elsevier By. All rights reserved.

Copulation is necessary for the completion of a gonotrophic cycle in the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae)

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Completion of the Nucleotide Sequence of a Brazilian Isolate of Southern bean mosaic virus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ultrasonic versus high-speed cavity preparation: Analysis of increases in pulpal temperature and time to complete preparation

Statement of problem. The use of ultrasonic tips has become an alternative for cavity preparation. However, there are concerns about this type of device, particularly with respect to intrapulpal temperatures and cavity preparation time.Purpose. The purpose of this study was to analyze pulpal temperature increases generated by an ultrasonic cavity preparation with chemical vapor deposition (CVD) tips, in comparison to preparation with a high-speed handpiece with a diamond rotary cutting instrument. The time required to complete the cavity preparation with each system was also evaluated.Material and methods. Thermocouples were positioned in the pulp chamber of 20 extracted human third molars. Slot-type cavities (3 x 3 x 2 mm) were prepared on the buccal and the lingual surfaces of each tooth. The test groups were: high-speed cavity preparation with diamond rotary cutting instruments (n = 20) and ultrasonic cavity preparation with CVD points (n = 20). During cavity preparation, the increases In pulpal temperature, and the time required for the preparation, were recorded and analyzed by Student's t test for paired samples (alpha = .05).Results. The average pulpal temperature increases were 4.3 degrees C for the high-speed preparation and 3.8 degrees C for the ultrasonic preparation, which were statistically similar (P = .052). However, significant differences were found (P < .001) for the time expended (3.3 minutes for the high-speed bur and 13.77 minutes for the ultrasound device).Conclusions. The intrapulpal temperatures produced during cavity preparation by ultrasonic tips versus high-speed bur preparation were similar. However, the use of the ultrasonic device required 4 times longer for the completion of a cavity preparation.

Naturally light invisible axion and local Z(13)circle times Z(3) symmetries

We show that by imposing local Z(13)circle timesZ(3) symmetries in an SU(2)circle timesU(1) electroweak model we can implement an invisible axion in such a way that (i) the Peccei-Quinn symmetry is an automatic symmetry of the classical Lagrangian, and (ii) the axion is protected from semiclassical gravitational effects. In order to be able to implement such a large discrete symmetry, and at the same time allow a general mixing in each charge sector, we introduce right-handed neutrinos and enlarge the scalar sector of the model. The domain wall problem is briefly considered.

SU(5)circle times Z(13) grand unification model

We propose an SU(5) grand unified model with an invisible axion and the unification of the three coupling constants which is in agreement with the values, at M(Z), of alpha, alpha(s), and sin(2)theta(W). A discrete, anomalous, Z(13) symmetry implies that the Peccei-Quinn symmetry is an automatic symmetry of the classical Lagrangian protecting, at the same time, the invisible axion against possible semiclassical gravity effects. Although the unification scale is of the order of the Peccei-Quinn scale the proton is stabilized by the fact that in this model the standard model fields form the SU(5) multiplets completed by new exotic fields and, also, because it is protected by the Z(13) symmetry.

Spin 1 fields in Riemann-Cartan space-times via Duffin-Kemmer-Petiau theory

We consider massive spin 1 fields, in Riemann-Cartan space-times, described by Duffin-Kemmer-Petiau theory. We show that this approach induces a coupling between the spin 1 field and the space-time torsion which breaks the usual equivalence with the Proca theory, but that such equivalence is preserved in the context of the Teleparallel Equivalent of General Relativity.