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.

OBJECTIVE: To assess the oral health status of community-dwelling adults aged 60 years and older from southern Brazil and to determine demographics, socioeconomic, behavioural and dental risk indicators. MATERIALS AND METHODS: This cross-sectional study used a multistage, probability sampling method to draw a representative sample of the metropolitan area of Porto Alegre, Brazil. A subsample of 217 subjects was included in this analysis. Oral mucosal lesions, dental caries, tooth loss and periodontal status (full-mouth, six sites per tooth exam) were assessed by calibrated examiners. RESULTS: Prevalence of edentulism was 39.5%, and mean tooth loss was 20.2 (SE = 0.6). Older individuals [Odds Ratio (OR) = 2.2], women (OR = 2.3), white people (OR = 5.9), individuals of lower socioeconomic status (OR = 5.6) and smokers (OR = 3.5) had higher likelihood of being edentulous. Approximately 36% of dentate individuals had caries and/or restoration affecting, in average, 5.0 teeth. Periodontitis affected 79% of subjects, and it was associated with older age (OR = 4.0), men (OR = 3.4) and large amounts of supragingival plaque (OR = 3.0). CONCLUSION: Poor oral health was observed in this elderly population from South Brazil. Sociodemographic disparities accounted for most of the burden of disease and treatment needs.

The statistical mechanical reformulation of weak turbulence theory for unmagnetized plasmas including fully electromagnetic effects was carried out by Yoon [Phys. Plasmas 13, 022302 (2006)]. However, the wave kinetic equation for the transverse wave ignores the nonlinear three-wave interaction that involves two transverse waves and a Langmuir wave, the incoherent analogue of the so-called Raman scattering process, which may account for the third and higher-harmonic plasma emissions. The present paper extends the previous formalism by including such a term.

Charged particle acceleration takes place ubiquitously in the Universe including the near-Earth heliospheric environment. Typical in situ spacecraft measurements made in the solar wind show that the charged particle velocity distribution contains energetic components with quasi scale-free power-law velocity dependence, f ∼ v − α , for high velocity range. In this Review a theory of quiet-time solar-wind electrons that contain a suprathermal component is discussed, in which these electrons are taken to be in dynamical equilibrium with Langmuir turbulence. This Review includes an overview of the Langmuir turbulence theory, as well as a discussion on asymptotic equilibrium solution of Langmuir turbulence/suprathermal electron system. Theoretical predictions of high-energy electron velocity power-law distribution index is then compared against the recent observations of the superhalo electron velocity distribution made by instruments onboard WIND and STEREO spacecraft. It is shown that the theoretical prediction of velocity power-law index is intermediate to the observed range.

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.

In a pair of recent papers (Ziebell et al 2008 Phys. Plasmas 15 032303, 2008 Plasma Phys. Control. Fusion 50 085011) it was shown, within the context of weak turbulence theory, that the Langmuir turbulence generated by the bump-in-tail instability does not lead to Langmuir condensation (or accumulation of wave energy and momentum in the long-wavelength regime) in two dimensions. The present analysis finds that it is important to include the spontaneous scattering off Langmuir turbulence of the electrons, which is ignored in the customary literature when compared with a similar process involving ions, in order to recover the condensation of Langmuir waves in two dimensions.