Hunting in Ancient and Modern Amazonia: Rethinking Sustainability

We use a recently developed computerized modeling technique to explore the long-term impacts of indigenous Amazonian hunting in the past, present, and future. The model redefines sustainability in spatial and temporal terms, a major advance over the static "sustainability indices" currently used to study hunting in tropical forests. We validate the model's projections against actual field data from two sites in contemporary Amazonia and use the model to assess various management scenarios for the future of Manu National Park in Peru. We then apply the model to two archaeological contexts, show how its results may resolve long-standing enigmas regarding native food taboos and primate biogeography, and reflect on the ancient history and future of indigenous people in the Amazon.

Morphological characterization of the nasopalatine region in human fetuses and its association to pathologies

The nasopalatine region is composed of structures such as the vomeronasal organ and nasopalatine duct. The nasopalatine duct may provide the communication of the mouth to the nasal cavity in human fetuses and can be obliterated in an adult human. Knowledge on the development of the nasopalatine region and nasopalatine duct in humans is necessary for understanding the morphology and etiopathogenesis of lesions that occur in this region. Objective: The aim of the present study was to describe the morphological aspects of the nasopalatine region in human fetuses and correlate these aspects with the development of pathologies in this region. Material and Methods: Five human fetuses with no facial or palatine abnormalities were used for the acquisition of specimens from the nasopalatine region. After demineralization, the specimens were histologically processed. Histological cuts were stained with methylene blue to orient the cutting plane and hematoxylin-eosin for the descriptive histological analysis. Results: The age of the fetuses was 8.00, 8.25, 9.00 and 9.25 weeks, and it was not possible to determine the age in the last one. The incisive canal was observed in all specimens as an opening delimited laterally by the periosteum and connecting oral and nasal cavity. The nasopalatine duct is an epithelial structure with the greatest morphological variation, with either unilateral or bilateral occurrence and total patent, partial patent and islet forms. The vomeronasal organ is a bilateral epithelized structure located alongside the nasal septum above the incisive canal in all the fetuses. Conclusions: The incisive canal, nasopalatine duct and vomeronasal organ are distinct anatomic structures. The development of nasopalatine duct cysts may occur in all forms of the nasopalatine duct.

Seismites as a tool in the palaeoenvironmental reconstruction of fluvial deposits: The Cambrian Guarda Velha Formation, southern Brazil

Soft-sediment deformation (SSD) is widely described in the literature, but there is no clear consensus regarding its origin and significance. Existing models for SSD in fluvial sediments do not clearly demonstrate a relationship between the structures, preserved facies expression, and larger-scale depositional architecture. In this study several types of SSD structures are recorded in Cambrian fluvial deposits and these occur interbedded with undeformed strata throughout the entire stratigraphic interval. The random distribution of these features in relation to primary facies types and fluvial forms indicates that they have neither a direct nor indirect relationship with any depositional processes or bedform type. We propose that the relationship of SSD at the bed-set-scale to larger-scale depositional architecture, combined with tectono-stratigraphic analysis allows the determination of both short-term fluvial hydraulic conditions in ancient stream systems, such as the nature of the flow regime responsible for depositing ancient fluvial stream successions, and the long-term subsidence rates, in the form of mean recurrence interval of the seismic events responsible for triggering the generation of SSD in tectonically active basins. (c) 2012 Elsevier B.V. All rights reserved.

Carbon isotope fractionation during calcium carbonate precipitation induced by urease-catalysed hydrolysis of urea

Stable carbon isotopic fractionation during calcium carbonate precipitation induced by urease-catalysed hydrolysis of urea was experimentally investigated in artificial water at a constant temperature of 30 degrees C. Carbon isotope fractionation during urea hydrolysis follows a Rayleigh distillation trend characterized by a C-13-enrichment factor of -20 to -22 parts per thousand. CaCO3 precipitate is up to 17.9 parts per thousand C-13-depleted relative to the urea substrate (-48.9 +/- 0.07 parts per thousand). Initial CaCO3 precipitate forms close to isotopic equilibrium with dissolved inorganic carbon. Subsequent precipitation occurs at -2 to -3 parts per thousand offset from isotopic equilibrium, suggesting that the initial delta C-13 value of CaCO3 is reset through dissolution followed by reprecipitation with urease molecules playing a role in offsetting the delta C-13 value of CaCO3 from isotopic equilibrium. Potentially, this isotopic systematics may provide a tool for the diagnosis of ureolytically-formed carbonate cements used as sealing agent. Moreover, it may serve as a basis to develop a carbon isotope tool for the quantification of ureolytically-induced CO2 sequestration. Finally, it suggests carbon isotope disequilibrium as a hallmark of past enzymatic activity in ancient microbial carbonate formation. (C) 2012 Elsevier B.V. All rights reserved.

Combined oral contraceptives and increasing cardiovascular risk: thromboembolism and hypertension

Background: Hormonal contraceptive pills are the most used reversible method for familiar planning in Brazil. The combined pill, with synthetic analogs of estrogen and progestin, is employed by 25% of Brazilian female population. Its use provokes an increase of blood pressure levels, takes patient to a hipercoagulability state and predisposes her to thromboembolic events. Purposes: We aimed to describe mechanisms of hypercoagulability promoted by oral combined contraceptives, to analyze the relative risk of cardiovascular events within users and to list the most common circulatory pathologies in these patients. Methods: Three virtual medical databases were surveyed (Pubmed/Medline, BVS/LILACS and Scielo). Twelve studies were selected: clinical trials, case reports and articles of indexed medical periodic originally published in Portuguese and English about synthetic hormones, oral contraception, coagulation disorders and cardiovascular morbimortality. Results: Synthetic estrogen promotes an increase of some clotting factors' levels (VII, VIII, IX, X, XII, XIII and fibrinogen), such as a reduction of their inhibitors (S protein and antithrombin). Because of this, etinilestradiol is the component most related to venous thrombosis and ischemic diseases of brain and heart. It also improves the releasing of hepatic angiotensinogen, taking to a increase of blood pressure levels. Conclusions: The prescription of oral combined contraceptives needs criteria, notably due to adverse effects of etinilestradiol. It is recommended to avoid the administration of these drugs for patients elder than 35 year-old or with risk factors. For these patients, the use of progestagen-only pills seems to be safer.

An ancient founder mutation in PROKR2 impairs human reproduction

Congenital gonadotropin-releasing hormone (GnRH) deficiency manifests as absent or incomplete sexual maturation and infertility. Although the disease exhibits marked locus and allelic heterogeneity, with the causal mutations being both rare and private, one causal mutation in the prokineticin receptor, PROKR2 L173R, appears unusually prevalent among GnRH-deficient patients of diverse geographic and ethnic origins. To track the genetic ancestry of PROKR2 L173R, haplotype mapping was performed in 22 unrelated patients with GnRH deficiency carrying L173R and their 30 first-degree relatives. The mutations age was estimated using a haplotype-decay model. Thirteen subjects were informative and in all of them the mutation was present on the same approximate to 123 kb haplotype whose population frequency is 10. Thus, PROKR2 L173R represents a founder mutation whose age is estimated at approximately 9000 years. Inheritance of PROKR2 L173R-associated GnRH deficiency was complex with highly variable penetrance among carriers, influenced by additional mutations in the other PROKR2 allele (recessive inheritance) or another gene (digenicity). The paradoxical identification of an ancient founder mutation that impairs reproduction has intriguing implications for the inheritance mechanisms of PROKR2 L173R-associated GnRH deficiency and for the relevant processes of evolutionary selection, including potential selective advantages of mutation carriers in genes affecting reproduction.