Amazonian Dark Earths: a case study in the Central Amazon

This investigation derives from research conducted over several years and contributes to the understanding of the differential occupational dynamics and use of space in pre-Colonial Amazonia. The goal of this study is to use traditional chemical and physical soil analytical methods to understand the archaeological site formation processes in the study area. Many of the sites in Amazonia have terra preta and terra mulata anthropogenic soils, that is, soils that are highly fertile and resilient, with elevated concentrations of pottery, charcoal, burials, and lithic and faunal remains. Because these soils have high pH values, the organic materials are well preserved for a tropical forest context. Testing a hypothesis about the use of these soils for food production during the pre-Colonial period was the main goal of this geoarchaeological research; the chronologies of occupation as well the size, shape and permanence of the villages during the pre-Colonial period are also included. The results show that the last occupational group - associated with the Guarita subtradition that occupied the site around 900 AD - discovered the fertile properties of these soils and reorganized them in order to improve their crop production. The evidence for this conclusion comes from chemical and physical analysis of the soils, which revealed a greater concentration of carbon (C) in the surface stratum of the site, while the amount of phosphorus (P) decreases with depth in that stratum. Moreover, a great and rapid spread of terra preta in the site surface corroborates these findings. Therefore, I deduce that a population around 900 AD introduced a different way to use the land; they farmed larger field areas for food production, decreasing the amount of P in the soil, because it was available for plants, but not of C, because carbon is mainly concentrated in black charcoal and is thus not available for plants. Slash-and-burn agriculture was the human action responsible for generating the black charcoal, and was used to increase soil fertility during crop production. The apparent change in land-use by the last group that occupied the site is related to the Amazon Polychromic Tradition (APT) that is associated with the Tupi expansion

Ventricular tachycardia originating from the left coronary aortic sinus

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Methylation status of Vitamin D receptor gene promoter in benign and malignant adrenal tumors

We previously showed a decreased expression of vitamin D receptor (VDR) mRNA/protein in a small group of adrenocortical carcinoma (ACC) tissues, suggesting the loss of a protective role of VDR against malignant cell growth in this cancer type. Downregulation of VDR gene expression may result from epigenetics events, that is, methylation of cytosine nucleotide of CpG islands in VDR gene promoter. We analyzed methylation of CpG sites in the VDR gene promoter in normal adrenals and adrenocortical tumor samples. Methylation of CpG-rich 5' regions was assessed by bisulfite sequencing PCR using bisulfite-treated DNA from archival microdissected paraffin-embedded adrenocortical tissues. Three normal adrenals and 23 various adrenocortical tumor samples (15 adenomas and 8 carcinomas) were studied. Methylation in the promoter region of VDR gene was found in 3/8 ACCs, while no VDR gene methylation was observed in normal adrenals and adrenocortical adenomas. VDR mRNA and protein levels were lower in ACCs than in benign tumors, and VDR immunostaining was weak or negative in ACCs, including all 3 methylated tissue samples. The association between VDR gene promoter methylation and reduced VDR gene expression is not a rare event in ACC, suggesting that VDR epigenetic inactivation may have a role in adrenocortical carcinogenesi

Calcium signaling in neurogenesis: regulation of proliferation, differentiation and migration of neural stem cells

The calcium ion (Ca2+) is a highly versatile and ubiquitous signaling messenger in all cell types. Signal transduction occurs through changes in the cytosolic Ca2+ concentration after the opening of Ca2+ channels in the plasma membrane (PM) and endoplasmic reticulum (ER). The difference in Ca2+ concentration between the extracellular space and the cytosol is large, around 10,000 fold, creating a steep gradient that causes Ca2+ to rapidly flow into the cell. Signaling via Ca2+ is fundamental for triggering numerous vital processes in the cell, ranging from fertilization to cell death. Calcium signaling is also critical for regulating neurogenesis in various ways, some of which have been explored in this work. Proliferation of neural progenitors is dependent on spontaneous Ca2+ activity that occurs in small-scale networks. Ca2+ activity is correlated with electrical activity both in vitro and in vivo and depends on connexin 43 gap junction and PM channels. Differentiation of neural progenitors is also regulated by Ca2+ signaling. We have found that T α1h voltage-dependent Ca2+ channels promote spontaneous Ca2+ activity and direct the differentiation of human neuroepithelial stem cells towards neurons, depending on caspase-3 enzymatic activity. These results were confirmed with T α1h knockout mice that showed a decreased number of neurons in the dorsal cortex. Neuronal migration also depends on Ca2+ signaling. We demonstrated that glial derived neurotrophic factor (GDNF) stimulates a Ca2+ response through the activation of the receptor tyrosine kinase (RET). The subsequent downstream signaling cascade includes phospholipase Cγ, which binds to RET Tyr1015. Mutating RET at Tyr1015 inhibits neuronal progenitor migration towards the cortical plate. We also showed that neurogenesis was altered by the addition of non-cytotoxic concentrations of polychlorinated biphenyls that disrupt spontaneous Ca2+ activity. Polychlorinated biphenyls are common food contaminants. In addition, methyl mercury, another food contaminant, disrupts neuronal differentiation in the opposite direction. Altogether, these data demonstrate the huge impact of Ca2+ signaling on the development of the embryonic brain. To conclude, we have analyzed Ca2+ signaling during three critical steps of neurogenesis: proliferation, differentiation, and migration. All of these processes are known to be dependent on Ca2+. A deeper understanding of how Ca2+ regulates such different physiological processes is crucial for the field of regenerative medicine, in which control of the expansion and differentiation of neural stem cells can increase the production of neuronal cells in vitro for use in cell replacement therapies

Is the Theatre a Zombie? On the Successful Failures of Émile Zola

AbstractNaturalist theatre, in its late-nineteenth-century incarnation, and particularly in the work of Émile Zola, is often seen as advancing a physicalist view of the mind, where all mind states can be reduced to brain states. The novels and the plays do not uniformly or unambiguously support this analysis, so is the theory or the practice wrong? Physicalism is an idea that has had a recent renaissance, helped by the discoveries of neuroscience. Nevertheless I express some caution about the claims made for the eradication of free will. A range of thought experiments in the philosophy of mind have cast doubt on physicalism, culminating in David Chalmers’s much-debated zombie argument. I argue that zombies and their analogues represented deep social anxieties in the late nineteenth century, and make repeated appearances in Naturalism. The essay goes on to suggest that Naturalism should be considered to have conducted thought experiments, rather than just to have attempted to embody the theory on stage. Turning to John Searle’s ‘Chinese Room’ thought experiment, I suggest that theatre-making itself may be a kind of thought experiment model of the mind.</jats:p

Listeria monocytogenes and Ready-to-Eat Meats: Tackling a Wicked Problem using Grounded Theory

Background: Listeria monocytogenes and ready-to-eat meats have garnered considerable attention in Canada over the past decade as a result of foodborne outbreaks and product recalls that continue to transpire. A number of factors suggest that ready-to-eat meats and Listeria monocytogenes are a wicked problem. They include (among others) the number of stakeholders involved in the processing, distribution and inspection of ready-to-eat meats in Ontario, the ubiquitous and hardy nature of the organism and the challenges associated with eliminating it from ready-to-eat meat products and processing environments. Since Ontario public health units play an integral part in the inspection of ready-to-eat meats in the province, it is important to determine their current role in the wicked problem in order to identify possible solutions for change. Purpose: The purposes of the study were: (1) to determine how Ontario public health units address the wicked problem of Listeria monocytogenes and ready-to-eat meats in their food safety inspection programs using the provincial regulatory framework in addition to the use of research, knowledge translation and innovation; and (2) to develop a theory that identifies gaps (if any) in public health unit inspection practices, provincial legislation or food safety research that serves to generate recommendations to reduce incidence of listeriosis resulting from consumption of RTE meat products. Methodology: The research design used the principles of grounded theory to lead the interview and survey methodology and subsequent data analyses. The study was completed in three phases. Interviews were conducted in the first 2 phases of the study while a survey was conducted in the last phase. Interviews were conducted with public health unit ‘food safety leads’ that met pre-determined eligibility criteria. Following methods used in previous studies,interview data were analyzed in 4 stages of theory development using a grounded theory approach. Through substantive coding and constant comparative methods, core categories were identified in each of the study phases. As a result, theoretical saturation was reached leading to the process of theoretical coding and the emergence of the study theory. Results: In total, 27 public health units of 36 participated in the study. Eleven public health units participated in the first 2 phases of the interviews while 25 public health units (for a total of 45 participants) participated in the survey. The study core category, 'reactive and regulatory practice' evolved from the results of the interviews and survey. As a result, it was determined that: (1) the Ontario provincial regulatory framework including the Food Premises Regulation is almost exclusively responsible for directing food safety inspection practices in food premises; (2) food safety inspection and investigation activities associated with listeriosis outbreaks are the focus of Listeria monocytogenes and ready-to-eat meat research; and (3) innovation and knowledge translation are not currently influenced by inspection practice as a result of the food safety framework which does not require or encourage it. Using the processes of theoretical integration and theoretical coding, the following theory emerged from the data analyses; Ontario public health units manage ready-to-eat meats and Listeria monocytogenes through general population and reactive regulatory processes that focus on local-level, end-product, hazard reduction strategies for established risks in inspected food premises. Strengths and Limitations: The study had several strengths including being the first of its kind to associate ready-to-eat meats and Listeria monocytogenes as a part of a wicked problem. It was also the first study to use grounded theory to illuminate the function and role of Ontario public health units in managing Listeria monocytogenes and ready-to-eat meats. There are a number of limitations to the study including the study sample size, participant inclusion process through provincial public health unit senior management, the generalizability of study results, and method of interviews conducted with participants. Implications: The results of the study have implications for public health researchers and policy/regulatory makers in the province of Ontario. It stresses improved management of Listeria monocytogenes and ready-to-eat meats in food premises using a proactive approach. Conclusions: Using a grounded theory approach, this study demonstrated that Ontario public health units manage ready-to-eat meats and Listeria monocytogenes through reactive and regulatory food safety inspection practices. Survey and interview results indicate that study participants aspire for evidence-based regulatory and program amendments that will allow for proactive and targeted microbial risk-reduction activities at the local level that focus on vulnerable populations. The study substantiates that amendments to the Ontario Food Safety program and in particular, the Food Premises Regulation are necessary