An Integrated Assessment of Archaeobotanical Recovery Methods in the Neotropical Rainforest of Northern Belize: Flotation and Dry Screening

This report presents results of a study examining the ancient use of plants at four Late Classic (CE 600-900) Maya rural farmsteads in northwestern Belize. Our research specifically targeted residential middens for macrobotanical recovery. Samples yielded the remains of more than a dozen plant families, representing some genera that do not currently grow in the area. These plants were used in the Late Classic, countering the idea that ancient botanical remains do not survive in Neotropical archaeological contexts. We also evaluated two macrobotanical sample processing methods vis-à-vis one another: flotation and dry screening. Our results indicate that flotation recovered 58% more seeds than dry screening, while dry screening yielded almost twice as much charcoal and other wood as flotation. The divergent quantities in the types of material recovered suggest a comprehensive macrobotanical recovery program should include the use of both processing methods

Role of transport performance on neuron cell morphology

The compartmental model is a basic tool for studying signal propagation in neurons, and, if the model parameters are adequately defined, it can also be of help in the study of electrical or fluid transport. Here we show that the input resistance, in different networks which simulate the passive properties of neurons, is the result of an interplay between the relevant conductances, morphology and size. These results suggest that neurons must grow in such a way that facilitates the current flow. We propose that power consumption is an important factor by which neurons attain their final morphological appearance.Comment: 9 pages with 3 figures, submitted to Neuroscience Letter

Quenched QCD at finite density

Simulations of quenched $QCD$ at relatively small but {\it nonzero} chemical potential $\mu$ on $32 \times 16^3$ lattices indicate that the nucleon screening mass decreases linearly as $\mu$ increases predicting a critical chemical potential of one third the nucleon mass, $m_N/3$, by extrapolation. The meson spectrum does not change as $\mu$ increases over the same range, from zero to $m_\pi/2$. Past studies of quenched lattice QCD have suggested that there is phase transition at $\mu = m_\pi/2$. We provide alternative explanations for these results, and find a number of technical reasons why standard lattice simulation techniques suffer from greatly enhanced fluctuations and finite size effects for $\mu$ ranging from $m_\pi/2$ to $m_N/3$. We find evidence for such problems in our simulations, and suggest that they can be surmounted by improved measurement techniques.Comment: 23 pages, Revte

Adaptive mesh refinement approach to construction of initial data for black hole collisions

The initial data for black hole collisions is constructed using a conformal-imaging approach and a new adaptive mesh refinement technique, a fully threaded tree (FTT). We developed a second-order accurate approach to the solution of the constraint equations on a non-uniformly refined high resolution Cartesian mesh including second-order accurate treatment of boundary conditions at the black hole throats. Results of test computations show convergence of the solution as the numerical resolution is increased. FTT-based mesh refinement reduces the required memory and computer time by several orders of magnitude compared to a uniform grid. This opens up the possibility of using Cartesian meshes for very high resolution simulations of black hole collisions.Comment: 13 pages, 11 figure

Systems-level analysis of age-related macular degeneration reveals global biomarkers and phenotype-specific functional networks

Abstract Background Age-related macular degeneration (AMD) is a leading cause of blindness that affects the central region of the retinal pigmented epithelium (RPE), choroid, and neural retina. Initially characterized by an accumulation of sub-RPE deposits, AMD leads to progressive retinal degeneration, and in advanced cases, irreversible vision loss. Although genetic analysis, animal models, and cell culture systems have yielded important insights into AMD, the molecular pathways underlying AMD's onset and progression remain poorly delineated. We sought to better understand the molecular underpinnings of this devastating disease by performing the first comparative transcriptome analysis of AMD and normal human donor eyes. Methods RPE-choroid and retina tissue samples were obtained from a common cohort of 31 normal, 26 AMD, and 11 potential pre-AMD human donor eyes. Transcriptome profiles were generated for macular and extramacular regions, and statistical and bioinformatic methods were employed to identify disease-associated gene signatures and functionally enriched protein association networks. Selected genes of high significance were validated using an independent donor cohort. Results We identified over 50 annotated genes enriched in cell-mediated immune responses that are globally over-expressed in RPE-choroid AMD phenotypes. Using a machine learning model and a second donor cohort, we show that the top 20 global genes are predictive of AMD clinical diagnosis. We also discovered functionally enriched gene sets in the RPE-choroid that delineate the advanced AMD phenotypes, neovascular AMD and geographic atrophy. Moreover, we identified a graded increase of transcript levels in the retina related to wound response, complement cascade, and neurogenesis that strongly correlates with decreased levels of phototransduction transcripts and increased AMD severity. Based on our findings, we assembled protein-protein interactomes that highlight functional networks likely to be involved in AMD pathogenesis. Conclusions We discovered new global biomarkers and gene expression signatures of AMD. These results are consistent with a model whereby cell-based inflammatory responses represent a central feature of AMD etiology, and depending on genetics, environment, or stochastic factors, may give rise to the advanced AMD phenotypes characterized by angiogenesis and/or cell death. Genes regulating these immunological activities, along with numerous other genes identified here, represent promising new targets for AMD-directed therapeutics and diagnostics. Please see related commentary: http://www.biomedcentral.com/1741-7015/10/21/abstrac

'Once there is life, there is hope' Ebola survivors' experiences, behaviours and attitudes in Sierra Leone, 2015.

BACKGROUND: In Sierra Leone, over 4000 individuals survived Ebola since the outbreak began in 2014. Because Ebola survivorship was largely unprecedented prior to this outbreak, little is known about survivor experiences during and post illness. METHODS: To assess survivors' experiences and attitudes related to Ebola, 28 in-depth interviews and short quantitative surveys with survivors from all four geographic regions of Sierra Leone were conducted in May 2015. RESULTS: Survivor experiences, emotions and attitudes changed over time as they moved from disease onset to treatment, discharge and life post-discharge. Survivors mentioned experiencing acute fear and depression when they fell ill. Only half reported positive experiences in holding centres but nearly all were positive about their treatment centre experiences. Survivor euphoria on discharge was followed by concerns about their financial situation and future. While all reported supportive attitudes from family members, about a third described discrimination and stigma from their communities. Over a third became unemployed, especially those previously engaged in petty trade. Survivor knowledge about sexual transmission risk reflected counselling messages. Many expressed altruistic motivations for abstinence or condom use. In addition, survivors were strongly motivated to help end Ebola and to improve the healthcare system. Key recommendations from survivors included improved counselling in holding centres and long-term government support for survivors, including opportunities for participation in Ebola response efforts. CONCLUSIONS: Survivors face myriad economic, social and health challenges. Addressing survivor concerns, including the discrimination they face, could facilitate their reintegration into communities and their contributions to future Ebola responses