Prominent effect of soil network heterogeneity on microbial invasion

Using a network representation for real soil samples and mathematical models for microbial spread, we show that the structural heterogeneity of the soil habitat may have a very significant influence on the size of microbial invasions of the soil pore space. In particular, neglecting the soil structural heterogeneity may lead to a substantial underestimation of microbial invasion. Such effects are explained in terms of a crucial interplay between heterogeneity in microbial spread and heterogeneity in the topology of soil networks. The main influence of network topology on invasion is linked to the existence of long channels in soil networks that may act as bridges for transmission of microorganisms between distant parts of soil

Complexity and anisotropy in host morphology make populations safer against epidemic outbreaks

One of the challenges in epidemiology is to account for the complex morphological structure of hosts such as plant roots, crop fields, farms, cells, animal habitats and social networks, when the transmission of infection occurs between contiguous hosts. Morphological complexity brings an inherent heterogeneity in populations and affects the dynamics of pathogen spread in such systems. We have analysed the influence of realistically complex host morphology on the threshold for invasion and epidemic outbreak in an SIR (susceptible-infected-recovered) epidemiological model. We show that disorder expressed in the host morphology and anisotropy reduces the probability of epidemic outbreak and thus makes the system more resistant to epidemic outbreaks. We obtain general analytical estimates for minimally safe bounds for an invasion threshold and then illustrate their validity by considering an example of host data for branching hosts (salamander retinal ganglion cells). Several spatial arrangements of hosts with different degrees of heterogeneity have been considered in order to analyse separately the role of shape complexity and anisotropy in the host population. The estimates for invasion threshold are linked to morphological characteristics of the hosts that can be used for determining the threshold for invasion in practical applications.Comment: 21 pages, 8 figure

Nanoscale assembly of lanthanum silica with dense and porous interfacial structures

This work reports on the nanoscale assembly of hybrid lanthanum oxide and silica structures, which form patterns of interfacial dense and porous networks. It was found that increasing the molar ratio of lanthanum nitrate to tetraethyl orthosilicate (TEOS) in an acid catalysed sol-gel process alters the expected microporous metal oxide silica structure to a predominantly mesoporous structure above a critical lanthanum concentration. This change manifests itself by the formation of a lanthanum silicate phase, which results from the reaction of lanthanum oxide nanoparticles with the silica matrix. This process converts the microporous silica into the denser silicate phase. Above a lanthanum to silica ratio of 0.15, the combination of growth and microporous silica consumption results in the formation of nanoscale hybrid lanthanum oxides, with the inter-nano-domain spacing forming mesoporous volume. As the size of these nano-domains increases with concentration, so does the mesoporous volume. The absence of lanthanum hydroxide (La(OH)(3)) suggests the formation of La2O3 surrounded by lanthanum silicate

Microreactors for biodiesel synthesis: design, fabrication, and characterization

The present work describes microreactors for biodiesel continuous synthesis that have been designed, fabricated, characterized, and aimed at achieving a reproducible microfluidic device to compose a modular portable biodiesel production demonstration unit. A straightforward method is presented for the microfabrication and sealing of the microfluidic device that performs the role of a microreactor for biodiesel synthesis, built on a brass metal base and sealed with either a metal cover or a glass cover for easy microscopic observation of two-phase flow patterns. The microfluidic device contains a Υ-junction squared microchannel architecture with width and depth of 400 µm. Microchannels were engraved using a micromilling technique and sealed either by welding, with tin as an additional material, in the case of the all metal device, or by using an epoxy glue, which served as an adhesive to seal a metal−glass device. The quality of the metal-on-metal seal was examined using microscopic analysis of multiple cross sections of the device, whereas the quality of the metal-on-glass seal was analyzed via direct visual inspection of flows within the device using an optical microscope to verify the existence or absence of leaks. An experimental setup was then built to carry out biodiesel synthesis in the metal−metal microreactor, using soybean oil of food grade, absolute ethanol, and sodium hydroxide, NaOH, as a catalyst for the reaction. For a molar ratio ethanol/oil 20:1, a quantity of NaOH catalyst of 1.0 wt.% at a controlled temperature of 47.5°C, it was possible to achieve a yield of fatty acids ethyl esters of 87.2% with 98% of triglyceride converted, for a residence time of 10 min. The experimental analysis confirms the applicability potential of the designed microreactor in the synthesis proposed.Indisponível

Carotenoid analysis of Cassava genotypes roots (Manihot Esculenta Crantz) cultivated in Southern Brazil using chemometric tools

Manihot esculenta roots rich in -carotene are an important staple food for populations with risk of vitamin A deficiency. Cassava genotypes with high pro-vitamin A activity have been identified as a strategy to reduce the prevalence of deficiency of this vitamin, In this study, the metabolomics characterization focusing on the carotenoid composition of ten cassava genotypes cultivated in southern Brazil by UV-visible scanning spectrophotometry and reverse phase-high performance liquid chromatography was performed. The data set was used for the construction of a descriptive model by chemometric analysis. The genotypes of yellow roots were clustered by the higher concentrations of cis--carotene and lutein. Inversely, cream roots genotypes were grouped precisely due to their lower concentrations of these pigments, as samples rich in lycopene differed among the studied genotypes. The analytical approach (UV-Vis, HPLC, and chemometrics) used showed to be efficient for understanding the chemodiversity of cassava genotypes, allowing to classify them according to important features for human health and nutrition.(undefined

Calcificação da cartilagem tritícea: características radiográficas

A cartilagem tritícea (TC) é uma pequena cartilagem de formato oval localizada na borda lateral da membrana tireo-hioidea entre o corno maior do osso hioide e o corno superior da cartilagem tireoide. A função exata do TC é desconhecida; sugere-se que a TC é o local de inserção do músculo trireoglosso. Nas radiografias panorâmicas, a TC pode apresentar-se calcificada, posicionando-se inferiormente ao corno maior do osso hioide e adjacente à borda superior da vértebra C4. O principal diagnóstico diferencial da calcificação da TC é a presença de ateroma calcificado da carótida, o que requer investigações imagiológicas adicionais. Este relato descreve e discute três casos em que as calcificações da TC foram incidentalmente encontradas em radiografias panorâmicas.The triticeal cartilage (TC) is a tiny oval-shaped cartilage located at the lateral border of the thyrohyoid membrane between the hyoid bone greater horn and the thyroid cartilage superior horn. The exact function o TC is unknown; it has been proposed that TC was the site of the attachment for the triticeoglossus muscle. On panoramic radiographs, calcified TC may be observed in the soft tissues of the pharynx region, positioned inferior to the greater horn of the hyoid bone and adjacent to the superior border of the C4 vertebrae. The major concern of a calcified TC found incidentally in a routine radiographic examination is the differentiation between this alteration and other calcified tissue manifestations that require additional investigations, such as carotid calcified atheroma artery or other neck pathology such as foreign bodies. Thus, this report describes 3 cases in which TC calcifications were incidentally found in panoramic radiographs

Rationale and design of the Anal HPV, HIV and Aging (AHHA) study: Protocol for a prospective study of anal HPV infection and HSIL among men who have sex (MSM) or trans women living with and without HIV, ages 50 and older.

INTRODUCTION: More than half of people living with HIV in the US are 50+ years old. Despite the benefits of antiretroviral therapy, older individuals with HIV are at higher risk for illnesses than their HIV-negative counterparts. Anal cancer, anal high-grade squamous intraepithelial lesions (HSIL), and anal HPV-16 infection occur most frequently among men who have sex with men living with HIV (MSMLWH). Men aged 60+ are 3-fold more likely to be diagnosed with anal cancer compared with younger men. Despite the increasing risk of anal cancer with age and HIV, little is known about the relationships among aging, HPV infection, HSIL and HIV. METHODS AND ANALYSIS: The Anal HPV, HIV, and Aging (AHHA) Study is a two-stage project to evaluate the relationships among anal HPV infection, HSIL, HIV infection, and biomarkers of biological aging in MSM or trans women over the age of 50 years. Stage 1 will estimate the cross-sectional prevalence of both anal HPV infection and HSIL, based on outcomes of anal HPV DNA testing, and high-resolution anoscopy with biopsy. We will also study associations with study outcomes and serological biomarkers of inflammation (interleukin-6, C-reactive protein, D-dimer) and with the Veterans Aging Cohort Study Index and the Fried Frailty Phenotype using multivariable models. Participants living with HIV (n = 150) and HIV-negative participants (n = 150) will be enrolled. The 3-year Stage 2 longitudinal sample restricted to HSIL-negative and anal HPV-16 DNA-negative participants will estimate the 3-year incidence of both anal HSIL and anal HPV, stratified by HIV status through Cox proportional hazards regression. The effect of biomarkers of inflammation and markers of aging on study outcomes will be evaluated through multivariable repeated measures models stratified by HIV status. ETHICS AND DISSEMINATION: This protocol was approved by the University of California, San Francisco Institutional Review Board (IRB: 16-18966). Results will be disseminated through presentations at national/international scientific conferences and publication in peer-reviewed journals

SkyMapper Southern Survey: First Data Release (DR1)

We present the first data release (DR1) of the SkyMapper Southern Survey, a hemispheric survey carried out with the SkyMapper Telescope at Siding Spring Observatory in Australia. Here, we present the survey strategy, data processing, catalogue construction and database schema. The DR1 dataset includes over 66,000 images from the Shallow Survey component, covering an area of 17,200 deg$^2$ in all six SkyMapper passbands $uvgriz$, while the full area covered by any passband exceeds 20,000 deg$^2$. The catalogues contain over 285 million unique astrophysical objects, complete to roughly 18 mag in all bands. We compare our $griz$ point-source photometry with PanSTARRS1 DR1 and note an RMS scatter of 2%. The internal reproducibility of SkyMapper photometry is on the order of 1%. Astrometric precision is better than 0.2 arcsec based on comparison with Gaia DR1. We describe the end-user database, through which data are presented to the world community, and provide some illustrative science queries.Comment: 31 pages, 19 figures, 10 tables, PASA, accepte

Drought impact on forest carbon dynamics and fluxes in Amazonia

In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the absence of growth. We propose that weakened maintenance and defence investment may, in turn, cause the increase in post-drought tree mortality observed at our plots.Gordon and Betty Moore FoundationNatural Environment Research Council (NERC)EU FP7 Amazalert (282664) projectEU FP7GEOCARBON (283080) projectNational Council for Scientific and Technological Development (CNPq, Brazil)ARC - fellowship awardERC - Advanced Investigator AwardRoyal Society - Wolfson Research Merit AwardJackson FoundationJohn Fell Fun

Ensaio de coluna para percolação de contaminantes em misturas solo-bentonita visando alternativa de barreira mineral em região costeira

O presente trabalho traz um estudo experimental da condutividade hidráulica e da percolação de íons inorgânicos em colunas de mistura de solo arenoso fino laterítico de origem eólica litorânea (solo ARMAR) e bentonita. Para os ensaios de percolação em colunas foi projetado e construído um equipamento que atendeu satisfatoriamente sua função na avaliação da retenção de contaminantes. O equipamento dispõe de um distribuidor de ar comprimido que impulsiona a solução contaminante, acondicionada em um reservatório, para ser percolada nas células de percolação. Foram produzidas curvas de permeabilidade, pH, condutividade elétrica para a fase de testes de percolação. Encontrou-se uma mistura tecnicamente viável para justificar investimentos na sua aplicação em liners e barreiras minerais (solo ARMAR + 4% de bentonita), visto que os resultados de condutividade hidráulica e de sorção de íons são condizentes com a legislação específica da área