Genomic history of coastal societies from eastern South America

Sambaqui (shellmound) societies are among the most intriguing archaeological phenomena in pre-colonial South America, extending from approximately 8,000 to 1,000 years before present (yr BP) across 3,000 km on the Atlantic coast. However, little is known about their connection to early Holocene hunter-gatherers, how this may have contributed to different historical pathways and the processes through which late Holocene ceramists came to rule the coast shortly before European contact. To contribute to our understanding of the population history of indigenous societies on the eastern coast of South America, we produced genome-wide data from 34 ancient individuals as early as 10,000 yr BP from four different regions in Brazil. Early Holocene hunter-gatherers were found to lack shared genetic drift among themselves and with later populations from eastern South America, suggesting that they derived from a common radiation and did not contribute substantially to later coastal groups. Our analyses show genetic heterogeneity among contemporaneous Sambaqui groups from the southeastern and southern Brazilian coast, contrary to the similarity expressed in the archaeological record. The complex history of intercultural contact between inland horticulturists and coastal populations becomes genetically evident during the final horizon of Sambaqui societies, from around 2,200 yr BP, corroborating evidence of cultural change.

Hypotrophic Roots of the Upper Central Incisors – a Proposed New Discrete Dental Trait

This paper describes a newly defined nonmetric trait in the human dentition, i.e., Hypotrophic Roots of the Upper Central Incisors (HRUCI). Teeth presenting HRUCI are characterized by abnormally short roots whose crowns exhibit no apparent morphological alterations. The trait was observed in six samples from collective funerary sites in the Iberian Peninsula dated from the Late Neolithic to the Chalcolithic period.

Unilateral absence of mandibular condyle in a Bronze Age male skeleton from Portugal

In 2009, a pit burial dated to the Bronze Age was excavated in Monte do Gato de Cima 3 (Portugal). The purpose of this paper is to describe the pathological absence of the left mandibular condyle noted in an adult male skeleton and to discuss possible diagnoses, including subcondylar fracture, cystic defect, congenital absence, condylar aplasia and mandibular condylysis. The most likely explanation for the pathological alteration is subcondylar fracture with non-union. Although the occurrence of non-union and slight osteoarthritic alterations in the left glenoid fossa were evident, this mandible was likely functional, as can be inferred from dental wear and muscle attachment sites. This trauma probably occurred before adult age when remodelling capacity is still high. Thus, bones and muscles adequately compensated for the trauma and only minor asymmetry developed. Consequently, this injury seems not to have greatly influenced masticatory functions. This is in accordance with clinical data, which demonstrate that, in growing patients, conservative treatment (non-surgical) results in good remodelling and patient recovery. In addition, in the few paleopathological cases published, the healing capacity of these types of mandibular fractures seems to be good, as can be inferred by evidence from the bone.

Stationary and dynamic critical behavior of the contact process on the Sierpinski carpet

We investigate the critical behavior of a stochastic lattice model describing a contact process in the Sierpinski carpet with fractal dimension d=log8/log3. We determine the threshold of the absorbing phase transition related to the transition between a statistically stationary active and the absorbing states. Finite-size scaling analysis is used to calculate the order parameter, order parameter fluctuations, correlation length, and their critical exponents. We report that all static critical exponents interpolate between the line of the regular Euclidean lattices values and are consistent with the hyperscaling relation. However, a short-time dynamics scaling analysis shows that the dynamical critical exponent Z governing the size dependence of the critical relaxation time is found to be larger then the literature values in Euclidean d=1 and d=2, suggesting a slower critical relaxation in scale-free lattices.

Aging and fluctuation-dissipation ratio in a nonequilibrium q-state lattice model

A generalized version of the nonequilibrium linear Glauber model with q states in d dimensions is introduced and analyzed. The model is fully symmetric, its dynamics being invariant under all permutations of the q states. Exact expressions for the two-time autocorrelation and response functions on a d-dimensional lattice are obtained. In the stationary regime, the fluctuation-dissipation theorem holds, while in the transient the aging is observed with the fluctuation-dissipation ratio leading to the value predicted for the linear Glauber model.

Time correlation function in systems with two coexisting biological species

We study a stochastic lattice model describing the dynamics of coexistence of two interacting biological species. The model comprehends the local processes of birth, death, and diffusion of individuals of each species and is grounded on interaction of the predator-prey type. The species coexistence can be of two types: With self-sustained coupled time oscillations of population densities and without oscillations. We perform numerical simulations of the model on a square lattice and analyze the temporal behavior of each species by computing the time correlation functions as well as the spectral densities. This analysis provides an appropriate characterization of the different types of coexistence. It is also used to examine linked population cycles in nature and in experiment.

Fluctuation-dissipation theorem and the linear Glauber model

We obtain exact expressions for the two-time autocorrelation and response functions of the -dimensional linear Glauber model. Although this linear model does not obey detailed balance in dimensions d > or = 2, we show that the usual form of the fluctuation-dissipation ratio still holds in the stationary regime. In the transient regime, we show the occurrence of aging, with a special limit of the fluctuation-dissipation ratio, x(infinity) = 1/2, for a quench at the critical point.

Nonequilibrium model for the contact process in an ensemble of constant particle number

We introduce and analyze numerically a nonequilibrium model with a conserved dynamics which is a realization of the contact process in an ensemble of constant particle number. The model possesses just one process in which particles jump around landing only on empty sites next to an existing particle. Particles are not allowed to land on a vacant site surrounded by empty sites. In contrast with the ordinary contact process, the present model does not have an absorbing state. In spite of lacking an absorbing state, the model displays properties that, in the thermodynamic limit, are identical to those of the ordinary contact process.

Universal behavior in an irreversible model with C(3v) symmetry

We analyze the critical behavior of a two-dimensional irreversible cellular automaton whose dynamic rules are invariant under the symmetry operations of the point group C3v. We study the dynamical phase transition that takes place in the model and obtain the static and short-time critical exponents by the use of Monte Carlo simulations. Our results indicate that the present model is in the same universality class as the three-state Potts model.

[A cost-benefit evaluation of prenatal diagnosis performed at a referral center with a population with a genetic or abnormality risk]

Prenatal diagnosis (PND) has assistencial, psychological and economical consequences; it is very important to evaluate cost effectiveness for the population. A prospective study was done (longitudinal and descriptive) on a population referred to Maternidade Dr. Alfredo da Costa, divided into two groups. Group one with PND performed on proper time and second group a PND procedure performed on a adequate time. The general characterization, indications for reference and consequences were evaluated. The conclusions are that the indications for reference were correct and the diagnosis was effective in 17% of patients. Social, economical levels and multiparity were the most important factors affecting adequate PND. However concerning the results, the termination of pregnancy was more performed on the group 1 and more abnormalities were seen on the newborns of group 2.