Structure and spatial distribution of Ge nanocrystals subjected to fast neutron irradiation

The influence of fast neutron irradiation on the structure and spatial distribution of Ge nanocrystals (NC) embedded in an amorphous SiO2 matrix has been studied. The investigation was conducted by means of laser Raman Scattering (RS), High Resolution Transmission Electron Microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). The irradiation of NC-Ge samples by a high dose of fast neutrons lead to a partial destruction of the nanocrystals. Full reconstruction of crystallinity was achieved after annealing the radiation damage at 800 deg. C, which resulted in full restoration of the RS spectrum. HR-TEM images show, however, that the spatial distributions of NC-Ge changed as a result of irradiation and annealing. A sharp decrease in NC distribution towards the SiO2 surface has been observed. This was accompanied by XPS detection of Ge oxides and elemental Ge within both the surface and subsurface region

Energy allocation trade-offs as a function of age in fungiid corals

To compete effectively, living organisms must adjust the allocation of available energy resources for growth, survival, maintenance, and reproduction throughout their life histories. Energy demands and allocations change throughout the life history of an organism, and understanding their energy allocation strategies requires determination of the relative age of individuals. As most scleractinian corals are colonial, the relationship between age and mass/size is complicated by colony fragmentation, partial mortality, and asexual reproduction. To overcome these limitations, solitary mushroom corals, Herpolitha limax from Okinawa, Japan and Fungia fungites from Okinawa and the Great Barrier Reef (GBR), Australia, were used to investigate how energy allocation between these fundamental processes varies as a function of age. Measurements of the relative growth, biochemical profiles, fecundity of individuals of different sizes, and the settlement success of their progeny have revealed physiological trade-offs between growth and reproduction, with increasing body mass ultimately leading to senescence. The importance of energy allocation for reproduction led us to examine the reproductive strategies and sex allocation in the two studied species. In the present study, the smallest individuals of both species studied were found to invest most of their energy in relative growth, showing higher lipid and carbohydrate content than the later stages. In medium-sized corals, this pattern was overturned in favour of reproduction, manifesting in terms of both the highest fecundity and settlement success of the resulting brooded larvae. Finally, a phase of apparent senescence was observed in the largest individuals, characterized by a decrease in most of the parameters measured. In addition, complex reproductive plasticity has been revealed in F. fungites in the GBR, with individual females releasing eggs, embryos, planulae, or a combination of these. These data provide the most direct estimates currently available for physiological, age-related trade-offs during the life history of a coral. The unusual reproductive characteristics of the GBR F. fungites indicate previously unknown layers of complexity in the reproductive biology of corals and have implications for their adaptive potential across a wide geographical scale

Anapole nanolasers for mode-locking and ultrafast pulse generation

Nanophotonics is a rapidly developing field of research with many suggestions for a design of nanoantennas, sensors and miniature metadevices. Despite many proposals for passive nanophotonic devices, the efficient coupling of light to nanoscale optical structures remains a major challenge. In this article, we propose a nanoscale laser based on a tightly confined anapole mode. By harnessing the non-radiating nature of the anapole state, we show how to engineer nanolasers based on InGaAs nanodisks as on-chip sources with unique optical properties. Leveraging on the near-field character of anapole modes, we demonstrate a spontaneously polarized nanolaser able to couple light into waveguide channels with four orders of magnitude intensity than classical nanolasers, as well as the generation of ultrafast (of 100 fs) pulses via spontaneous mode locking of several anapoles. Anapole nanolasers offer an attractive platform for monolithically integrated, silicon photonics sources for advanced and efficient nanoscale circuitry

Role of BMP, FGF, Calcium Signaling, and Zic Proteins in Vertebrate Neuroectodermal Differentiation

More than a decade has passed since Zic family zinc finger proteins were discovered to be transcription factors controlling neuroectodermal differentiation (neural induction) in Xenopus laevis embryos. Although BMP-signal blocking has been shown to be a major upregulator of Zic genes in neuroectodermal differentiation, recent studies have revealed that FGF signaling and intracellular calcium elevation are also involved in regulating the expression of Zic genes. Different regulatory mechanisms have been found for the Zic1 and Zic3 genes, raising the possibility that functional synergism between them partly accounts for the integration of BMP-signal blocking and FGF signaling in neuroectodermal differentiation. Furthermore, mammalian Zic1 and Zic3 have been found to be neural-cell-fate-inducing and pluripotency-maintaining factors, respectively, leading us to the intriguing question of whether the mechanism underlying amphibian neuroectodermal differentiation is applicable to mammals. Comprehensive understanding of the Zic family genes is therefore essential for the study of the neuroectodermal differentiation and stem cell biology

An Indo-Pacific coral spawning database.

The discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology

The Chlamydia psittaci Genome: A Comparative Analysis of Intracellular Pathogens

Chlamydiaceae are a family of obligate intracellular pathogens causing a wide range of diseases in animals and humans, and facing unique evolutionary constraints not encountered by free-living prokaryotes. To investigate genomic aspects of infection, virulence and host preference we have sequenced Chlamydia psittaci, the pathogenic agent of ornithosis.A comparison of the genome of the avian Chlamydia psittaci isolate 6BC with the genomes of other chlamydial species, C. trachomatis, C. muridarum, C. pneumoniae, C. abortus, C. felis and C. caviae, revealed a high level of sequence conservation and synteny across taxa, with the major exception of the human pathogen C. trachomatis. Important differences manifest in the polymorphic membrane protein family specific for the Chlamydiae and in the highly variable chlamydial plasticity zone. We identified a number of psittaci-specific polymorphic membrane proteins of the G family that may be related to differences in host-range and/or virulence as compared to closely related Chlamydiaceae. We calculated non-synonymous to synonymous substitution rate ratios for pairs of orthologous genes to identify putative targets of adaptive evolution and predicted type III secreted effector proteins.This study is the first detailed analysis of the Chlamydia psittaci genome sequence. It provides insights in the genome architecture of C. psittaci and proposes a number of novel candidate genes mostly of yet unknown function that may be important for pathogen-host interactions

A mRNA landscape of bovine embryos after standard and MAPK-inhibited culture conditions: a comparative analysis.

BACKGROUND: Genes and signalling pathways involved in pluripotency have been studied extensively in mouse and human pre-implantation embryos and embryonic stem (ES) cells. The unsuccessful attempts to generate ES cell lines from other species including cattle suggests that other genes and pathways are involved in maintaining pluripotency in these species. To investigate which genes are involved in bovine pluripotency, expression profiles were generated from morula, blastocyst, trophectoderm and inner cell mass (ICM) samples using microarray analysis. As MAPK inhibition can increase the NANOG/GATA6 ratio in the inner cell mass, additionally blastocysts were cultured in the presence of a MAPK inhibitor and changes in gene expression in the inner cell mass were analysed. RESULTS: Between morula and blastocyst 3,774 genes were differentially expressed and the largest differences were found in blastocyst up-regulated genes. Gene ontology (GO) analysis shows lipid metabolic process as the term most enriched with genes expressed at higher levels in blastocysts. Genes with higher expression levels in morulae were enriched in the RNA processing GO term. Of the 497 differentially expressed genes comparing ICM and TE, the expression of NANOG, SOX2 and POU5F1 was increased in the ICM confirming their evolutionary preserved role in pluripotency. Several genes implicated to be involved in differentiation or fate determination were also expressed at higher levels in the ICM. Genes expressed at higher levels in the ICM were enriched in the RNA splicing and regulation of gene expression GO term. Although NANOG expression was elevated upon MAPK inhibition, SOX2 and POU5F1 expression showed little increase. Expression of other genes in the MAPK pathway including DUSP4 and SPRY4, or influenced by MAPK inhibition such as IFNT, was down-regulated. CONCLUSION: The data obtained from the microarray studies provide further insight in gene expression during bovine embryonic development. They show an expression profile in pluripotent cells that indicates a pluripotent, epiblast-like state. The inability to culture ICM cells as stem cells in the presence of an inhibitor of MAPK activity together with the reported data indicates that MAPK inhibition alone is not sufficient to maintain a pluripotent character in bovine cells

An Indo-Pacifc coral spawning database

The discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology

Prevalencia de esofagitis eosinofílica: estudio multicéntrico en población pediátrica evaluada en 36 centros de gastroenterología de América Latina

Introducción y objetivo: La esofagitis eosinofílica es una enfermedad crónica, mediada inmunológicamente, descrita en series y publicaciones alrededor del mundo. En los últimos 20 años diversos estudios han intentado evaluar la incidencia y prevalencia de la enfermedad. El objetivo del presente trabajo es estimar la prevalencia de esofagitis eosinofílica en un grupo de niños atendidos en 36 centros de gastroenterología pediátrica de 10 países latinoamericanos. Materiales y métodos: A través de un protocolo multicéntrico, observacional y transversal se estimó la prevalencia de período de esofagitis eosinofílica entre los niños atendidos en consulta externa y sometidos a endoscopia superior diagnóstica por cualquier motivo en 36 centros de 10 países latinoamericanos durante un período de 3 meses. Resultados: Entre abril y junio de 2016 108 casos de esofagitis eosinofílica fueron evaluados. Asimismo, un promedio de 29,253 consultas ambulatorias y 4,152 endoscopias superiores de carácter diagnóstico fueron realizadas en los 36 centros participantes. La tasa de prevalencia de esofagitis eosinofílica en la población estudiada (n = 29,253) fue de 3,69 casos × 1,000 (IC 95%: 3.04 a 4.44) y entre los niños sometidos a endoscopia superior de rutina (n = 4,152) fue de 26 x 1,000 (IC 95%: 22.6 a 29.4). Conclusión: La tasa general de prevalencia de período de esofagitis eosinofílica en un grupo de niños evaluados en 36 centros latinoamericanos de gastroenterología pediátrica resultó de 3,69 × 1,000, y entre aquellos sometidos a endoscopia fue de 26 × 1,000. La prevalencia mostró una importante variabilidad entre los países y centros participantes. Este es el primer estudio de prevalencia de esofagitis eosinofílica pediátrica en Latinoamérica. Abstract: Introduction and objective: Eosinophilic esophagitis is a chronic, immune-mediated disease described in case series and publications worldwide. Over the past twenty years, the authors of different studies have attempted to evaluate its incidence and prevalence. The objetive of the present study was to estimate the prevalence of eosinophilic esophagitis in a group of children seen at 36 pediatric gastroenterology centers in ten Latin American countries. Materials and methods: A multicenter, observational, and cross-sectional study was conducted that estimated the period prevalence of eosinophilic esophagitis in children seen at outpatient consultation and that underwent diagnostic upper gastrointestinal endoscopy for any indication at 36 centers in 10 Latin American countries, within a 3-month time frame. Results: Between April and June 2016, 108 cases of eosinophilic esophagitis were evaluated. Likewise, an average of 29,253 outpatient consultations and 4,152 diagnostic upper gastrointestinal endoscopies were carried out at the 36 participating centers. The period prevalence of eosinophilic esophagitis in the population studied (n = 29,253) was 3.69 cases × 1,000 (95% CI: 3.04 to 4.44), and among the children that underwent routine upper gastrointestinal endoscopy (n = 4,152), it was 26 x 1,000 (95% CI: 22.6 to 29.4). Conclusions: The general period prevalence of eosinophilic esophagitis in a group of children evaluated at 36 Latin American pediatric gastroenterology centers was 3.69 × 1,000, and in the children that underwent endoscopy, it was 26 × 1,000. There was important prevalence variability between the participating countries and centers. The present analysis is the first study conducted on the prevalence of pediatric eosinophilic esophagitis in Latin America. Palabras clave: Esofagitis, Eosinofílica, Niños, Prevalencia, Latinoamérica, Keywords: Esophagitis, Eosinophilic, Children, Prevalence, Latin Americ

SEIS: Insight’s Seismic Experiment for Internal Structure of Mars

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars’ surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking’s Mars seismic monitoring by a factor of ∼ 2500 at 1 Hz and ∼ 200 000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars’ surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of Mw ∼ 3 at 40◦ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution