The Prediction Error Method (PEM) is related to an optimization problem built on input/output data collected from the system to be identified. It is often hard to find the global solution of this optimization problem because the corresponding objective function presents local minima and/or the search space is constrained to a nonconvex set. The shape of the cost function, and hence the difficulty in solving the optimization problem, depends directly on the experimental conditions, more specifically on the spectrum of the input/output data collected from the system. Therefore, it seems plausible to improve the convergence to the global minimum by properly choosing the spectrum of the input; in this paper, we address this problem. We present a condition for convergence to the global minimum of the cost function and propose its inclusion in the input design. We present the application of the proposed approach to case studies where the algorithms tend to get trapped in nonglobal minima.

The South America southern coast exhibits many outcrops with abundant shell beds, from the Pleistocene through the Recent. How much biological information is preserved within these shell beds? Or, what is the actual probability a living community has to leave a fossil record corresponding to these shell deposits? Although ecological and biogeographical aspects might had been pointed, considering these temporal scales, up to the moment there is no taphonomically-oriented studies available. Quantitative comparisons between living (LAs), death (DAs) and fossil assemblages (FAs) are important not only in strictly taphonomic studies, but have grown a leading tool for conservation paleobiology analysis. Comparing LAs, DAs and FAs from estuaries and lagoons in the Rio Grande do Sul Coastal Plain makes possible to quantitatively understand the nature and quantity of biological information preserved in fossil associations in Holocene lagoon facies. As already noted by several authors, spatial scale parts the analysis, but we detected that the FAs reflects live ones, rather than dead ones, as previously not realized. The results herein obtained illustrates that species present in DA are not as good preserved in recent (Holocene) fossil record as originally thought. Strictly lagoon species are most prone to leave fossil record. The authors consider that the fidelity pattern here observed for estuarine mollusks to be driven by (i) high temporal and spatial variability in the LAs, (ii) spatial mixing in the DA and (iii) differential preservation of shells, due to long residence times in the taphonomically active zone. © 2013 by the Sociedade Brasileira de Paleontologia.

The South America southern coast exhibits many outcrops with abundant shell beds, from the Pleistocene through the Recent. How much biological information is preserved within these shell beds? Or, what is the actual probability a living community has to leave a fossil record corresponding to these shell deposits? Although ecological and biogeographical aspects might had been pointed, considering these temporal scales, up to the moment there is no taphonomically-oriented studies available. Quantitative comparisons between living (LAs), death (DAs) and fossil assemblages (FAs) are important not only in strictly taphonomic studies, but have grown a leading tool for conservation paleobiology analysis. Comparing LAs, DAs and FAs from estuaries and lagoons in the Rio Grande do Sul Coastal Plain makes possible to quantitatively understand the nature and quantity of biological information preserved in fossil associations in Holocene lagoon facies. As already noted by several authors, spatial scale parts the analysis, but we detected that the FAs refl ects live ones, rather than dead ones, as previously not realized. The results herein obtained illustrates that species present in DA are not as good preserved in recent (Holocene) fossil record as originally thought. Strictly lagoon species are most prone to leave fossil record. The authors consider that the fi delity pattern here observed for estuarine mollusks to be driven by (i) high temporal and spatial variability in the LAs, (ii) spatial mixing in the DA and (iii) differential preservation of shells, due to long residence times in the taphonomically active zone.

Molluscan shell accumulations (shell beds) are very common in shallow marine and estuarine environments in South America and also on the continental shelf between Argentina and southern Brazil. The development of these shell beds is restricted to the Quaternary, and can provide a great opportunity for taphonomic studies, which are rare in this geographic location. This study investigates the influence of environmental processes on the destruction of biological remains in a subtropical lagoonal setting by describing the taphonomic signatures occurring in the mollusk shells from the Tramandaí Lagoon, northeastern Rio Grande do Sul State, Brazil. This lagoon system originated during the regressive phase that followed a transgressive maximum at 6.0-6.5 ka BP. The taphonomic variables (fragmentation, margin modification, surface alteration, hinge fine scale alteration and corrosion degree) and their damage states were recorded for 1000 shells of Erodona mactroides. The shells were recovered from two outcrops 8 km apart. 14 C-AMS dating were performed on the shells of E. mactroides from those outcrops, which yielded similar ages (from 1060 to 1490 cal yrs BP). The ages would indicate that the Tramandaí Lagoon occupied a larger area and must have been subjected to very rapid progradation towards its present position. Several taphonomic variables, such as fragmentation, surface alteration, and corrasion extent and oxidation, presented significant differences (p {\textless} 0.01) between the two outcrops. This may be due to some natural variation of the estuarine and lagoonal environments or differences within the taphonomically active zone (TAZ). Dissolution seems to be a leading taphonomic agent in lagoonal environments. The shells from the two outcrops are within the TAZ and, due to intense dissolution, they will most likely leave no geological record. © 2013 Elsevier Ltd and INQUA.

The purpose of the present paper was to describe the range of lesions histologically diagnosed in an oral pathology laboratory in southern Brazil. A retrospective study of 8,168 specimen analyses recorded between 1995 and 2004 was conducted. The records were retrieved from the Oral Pathology Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, RS, Brazil. A total of 6,831 valid cases (83.63%) were examined. Of these, inflammatory lesions were the most common occurrences (n = 4,320; 63.24%). Benign and malignant tumors accounted for 7.66% (n = 523) and 1.9% (n = 130) of the occurrences, respectively. Significant associations were observed between nonneoplastic proliferative disorders and benign mesenchymal tumors in females, and between squamous cell carcinoma and leukoplakia in males. Most diagnoses were benign in nature and had an inflammatory etiology. The association of some demographic characteristics with the occurrence of lesions suggests that these characteristics should be considered in performing differential diagnoses.

OBJECTIVES: To compare the subgingival microbiological outcomes of azithromycin or placebo as adjuncts to scaling and root planing (SRP) in the treatment of aggressive periodontitis (AgP), and to secondarily evaluate the microbiological effect of supragingival scaling in AgP patients. METHODS: Twenty-four AgP subjects 13-26 years of age received a 15-day programme of supragingival scaling (SC) and were then randomly assigned to SRP with systemic azithromycin or placebo. Subgingival samples were taken with sterile paper points at baseline, 15 days after SC, and at 3, 6 and 12 months following SRP. Microbiological analysis was performed by the checkerboard DNA-DNA hybridization. RESULTS: Changes in bacterial levels from baseline to 15 days after SC were similar in the 2 groups. When subjects were analysed as a single group, significant reductions after SC were observed for Actinomyces gerencseriae, Capnocytophaga ochracea, and Treponema denticola. During the 12-month follow-up, levels of most of the bacteria decreased in both groups in a similar pattern. For instance, Actinomyces israelli, Veillonella parvula, Streptococcus gordonii, C. ochracea, Eikenella corrodens, Eubacterium nodatum, Fusobacterium periodonticum and Fusobacterium nucleatum ssp. polymorphum decreased significantly within the groups. CONCLUSIONS: Azithromycin was ineffective in lowering the subgingival levels of important putative periodontal pathogens in young AgP subjects compared to placebo. CLINICAL SIGNIFICANCE: Scaling and root planing with adjunctive systemic azithromycin provides little additional benefit compared to placebo in reductions of major subgingival periodontal pathogens.

AIM: The aim of this 5-years longitudinal study was to investigate the pattern and rate of periodontal attachment loss (PAL) progression in an urban population in South Brazil. METHODS: In 2001, a multistage probability sampling strategy was used to derive a representative sample of 1,465 dentate individuals from Porto Alegre, Brazil. Five years later, 697 dentate individuals (294M/403F, mean age: 37.9 +/- 13.3) were available for follow-up. PAL was assessed by calibrated examiners using a full-mouth protocol. Estimates of proximal PAL progression and standard errors (SE) are reported. RESULTS: Fifty-six per cent (SE: 1.9) and 36% (SE: 1.8) of subjects showed PAL progression >/=3 mm affecting >/=2 and >/=4 teeth respectively. PAL progression >/=3 mm was mostly localized affecting 3.8 (SE: 0.2) teeth and 5.7 (SE: 0.3) sites. Annual PAL progression was, on average, 0.3 mm (SE: 0.01). Significant differences in PAL progression were observed according to age, gender, race and socioeconomic status. PAL progression increased with age reaching the highest progression rate in the 40-49 years cohort, and then decreased in older age groups. PAL progression was consistently higher among males and non-Whites than females and whites. CONCLUSION: A large proportion of this urban Brazilian sample was affected by PAL progression underscoring the need for health promotion initiatives aiming at preventing progression of destructive periodontal disease.

PURPOSE: To compare the 12-month radiographic outcomes following the use of azithromycin or placebo as adjuncts to non-surgical periodontal treatment of AgP. METHODS: 17 aggressive periodontitis (AgP) subjects 13-26 years old were randomly assigned to receive scaling and root planing (SRP) with systemic azithromycin or placebo. Standardized radiographs were taken at baseline and 12 months postoperatively. Recall visits consisting of oral prophylaxis and oral hygiene instructions were performed during the 12 months. Digital image subtraction analysis and linear bone measurements were conducted by a blinded and calibrated examiner. Student t-tests were used for within and between-groups comparisons. ANCOVA was applied for between-group comparisons of changes in linear bone level adjusting for baseline values. RESULTS: There were significant gains in linear bone levels in the azithromycin (0.55 +/- 0.10 mm) and placebo (0.42 +/- 0.07 mm) groups between the baseline and 12-month postoperative visits. There were also significant gains in bone density in the two treatment groups. No significant differences were observed between the two treatments in the amount of linear bone gain or bone density during the follow-up period. The use of azithromycin as an adjunct to SRP in the treatment of AgP did not result in significant radiographic bone level changes compared to placebo.