228 research outputs found
Spatial Patterns of Iron- and Methane-Oxidizing Bacterial Communities in an Irregularly Flooded, Riparian Wetland
Iron- and methane-cycling are important processes in wetlands with one connected to plant growth and the other to greenhouse gas emission, respectively. In contrast to acidic habitats, there is scarce information on the ecology of microbes oxidizing ferrous iron at circumneutral pH. The latter is mainly due to the lack of isolated representatives and molecular detection techniques. Recently, we developed PCR–DGGE and qPCR assays to detect and enumerate Gallionella-related neutrophilic iron-oxidizers (Ga-FeOB) enabling the assessment of controlling physical as well as biological factors in various ecosystems. In this study, we investigated the spatial distribution of Ga-FeOB in co-occurrence with methane-oxidizing bacteria (MOB) in a riparian wetland. Soil samples were collected at different spatial scales (ranging from meters to centimeters) representing a hydrological gradient. The diversity of Ga-FeOB was assessed using PCR–DGGE and the abundance of both Ga-FeOB and MOB by qPCR. Geostatistical methods were applied to visualize the spatial distribution of both groups. Spatial distribution as well as abundance of Ga-FeOB and MOB was clearly correlated to the hydrological gradient as expressed in moisture content of the soil. Ga-FeOB outnumbered the MOB subgroups suggesting their competitiveness or the prevalence of Fe2+ over CH4 oxidation in this floodplain
Implementing Surveillance and Outbreak Response Management and Analysis System (SORMAS) for Public Health in West Africa-Lessons Learnt and Future Direction
Electromagnetic transitions in an effective chiral Lagrangian with the eta-prime and light vector mesons
We consider the chiral Lagrangian with a nonet of Goldstone bosons and a
nonet of light vector mesons. The mixing between the pseudoscalar mesons eta
and eta-prime is taken into account. A novel counting scheme is suggested that
is based on hadrogenesis, which conjectures a mass gap in the meson spectrum of
QCD in the limit of a large number of colors. Such a mass gap would justify to
consider the vector mesons and the eta-prime meson as light degrees of freedom.
The complete leading order Lagrangian is constructed and discussed. As a first
application it is tested against electromagnetic transitions of light vector
mesons to pseudoscalar mesons. Our parameters are determined by the
experimental data on photon decays of the omega, phi and eta-prime meson. In
terms of such parameters we predict the corresponding decays into virtual
photons with either dielectrons or dimuons in the final state.Comment: 17 pages, extended discussion on mixin
Understanding Animal Group-Size Distributions
One of the most striking aspects of animal groups is their remarkable variation in size, both within and between species. While a number of mechanistic models have been proposed to explain this variation, there are few comprehensive datasets against which these models have been tested. In particular, we only vaguely understand how environmental factors and behavioral activities affect group-size distributions. Here we use observations of House sparrows (Passer domesticus) to investigate the factors determining group-size distribution. Over a wide range of conditions, we observed that animal group sizes followed a single parameter distribution known as the logarithmic distribution. This single parameter is the mean group size experienced by a randomly chosen individual (including the individual itself). For sparrows, the experienced mean group size, and hence the distribution, was affected by four factors: morning temperature, place, behavior and the degree of food spillage. Our results further indicate that the sparrows regulate the mean group size they experience, either by groups splitting more or merging less when local densities are high. We suggest that the mean experienced group size provides a simple but general tool for assessing the ecology and evolution of grouping
Protective role of chaperone-mediated autophagy against atherosclerosis
Chaperone-mediated autophagy (CMA) contributes to regulation of energy homeostasis by timely degradation of enzymes involved in glucose and lipid metabolism. Here, we report reduced CMA activity in vascular smooth muscle cells and macrophages in murine and human arteries in response to atherosclerotic challenges. We show that in vivo genetic blockage of CMA worsens atherosclerotic pathology through both systemic and cell-autonomous changes in vascular smooth muscle cells and macrophages, the two main cell types involved in atherogenesis. CMA deficiency promotes dedifferentiation of vascular smooth muscle cells and a proinflammatory state in macrophages. Conversely, a genetic mouse model with up-regulated CMA shows lower vulnerability to proatherosclerotic challenges. We propose that CMA could be an attractive therapeutic target against cardiovascular diseases
Оценка фискальной иллюзии при налогообложении доходов физических лиц
Фискальная иллюзия сама по себе не является негативным явлением, она всего лишь следствие осуществляемой фискальной политики государства. Тем не менее, фискальная иллюзия нарушает представление экономических агентов о масштабах государственного влияния в перераспределении своих доходов и тем самым способствует принятию ими не самых эффективных экономических решений.Фіскальна ілюзія сама по собі не є негативним явищем, вона всього лише слідство здійснюваної фіскальної політики держави. Проте, фіскальна ілюзія порушує уявлення економічних агентів про масштаби державного впливу в перерозподілі своїх доходів і тим самим сприяє ухваленню ними не найефективніших економічних рішень
Integrated quantum photonic sensor based on Hong-Ou-Mandel interference
Photonic-crystal-based integrated optical systems have been used for a broad range of sensing applications with great success. This has been motivated by several advantages such as high sensitivity, miniaturization, remote sensing, selectivity and stability. Many photonic crystal sensors have been proposed with various fabrication designs that result in improved optical properties. In parallel, integrated optical systems are being pursued as a platform for photonic quantum information processing using linear optics and Fock states. Here we propose a novel integrated Fock state optical sensor architecture that can be used for force, refractive index and possibly local temperature detection. In this scheme, two coupled cavities behave as an “effective beam splitter”. The sensor works based on fourth order interference (the Hong-Ou-Mandel effect) and requires a sequence of single photon pulses and consequently has low pulse power. Changes in the parameter to be measured induce variations in the effective beam splitter reflectivity and result in changes to the visibility of interference. We demonstrate this generic scheme in coupled L3 photonic crystal cavities as an example and find that this system, which only relies on photon coincidence detection and does not need any spectral resolution, can estimate forces as small as 10^−7 Newtons and can measure one part per million change in refractive index using a very low input power of 10−10W. Thus linear optical quantum photonic architectures can achieve comparable sensor performance to semiclassical devices
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
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