132 research outputs found
The Effects of Long Term Agricultural Production on Soil Microbial Diversity
Soil microorganisms are important facilitators of ecosystem functions including: crop and pesticide residue decomposition, carbon sequestration, Nitrogen (N) fixation and nutrient cycling. Therefore, the abundance and diversity of soil microorganisms may act as a buffer against stress and change, ensuring that soils remain productive. The Rotation ABC Long term soil experiment (LTSE) at Lethbridge, Alberta provides an opportunity to use modern molecular tools to study microbial dynamics in response to over a century of agricultural land management. My goals were to assess cumulative effects of N fertilizer and different cropping intensities (CI) on soil microbial community abundance and diversity, both in soils collected in 2012 and in the soils archived over 100 years of wheat production. Soil microbial community abundance and diversity of soils collected in 2012 were influenced by N fertilization and CI. Phospholipid fatty acid (PLFA) analysis of the 2012 soils revealed a positive relationship between N fertilizer application and CI on the total active biomass. Quantitative PCR analysis showed that N functional gene abundances were affected by significant interactions between N fertilizer and CI, and the abundances of denitrifier genes (nosZ and nirK) were also strongly influenced by higher levels of CI in the 2012 soils. A short term soil storage experiment indicated that storage time and fertilizer treatment (45 kg N ha-1, 20 kg P ha-1 vs. unfertilized) influenced the amount of DNA extracted. In addition, the results suggested that N and P fertilized soils had greater bacterial diversity than unfertilized soils. Through the use of 16S rRNA gene profiling with these soils the results suggested that bacterial diversity and richness was lowest in the oldest samples, implying a shift over decades of agricultural production. Soils collected after the introduction of N fertilizer displayed an increase in N function gene abundances, indicating an increase in N cycling potential. Overtime, the changes in agricultural land management led to increased plant and soil productivity, resulting in a positive relationship between years under agricultural land management and soil bacterial diversity and abundance.
Regulation of size and scale in vertebrate spinal cord development
All vertebrates have a spinal cord with dimensions and shape specific to their species. Yet how species‐specific organ size and shape are achieved is a fundamental unresolved question in biology. The formation and sculpting of organs begins during embryonic development. As it develops, the spinal cord extends in anterior–posterior direction in synchrony with the overall growth of the body. The dorsoventral (DV) and apicobasal lengths of the spinal cord neuroepithelium also change, while at the same time a characteristic pattern of neural progenitor subtypes along the DV axis is established and elaborated. At the basis of these changes in tissue size and shape are biophysical determinants, such as the change in cell number, cell size and shape, and anisotropic tissue growth. These processes are controlled by global tissue‐scale regulators, such as morphogen signaling gradients as well as mechanical forces. Current challenges in the field are to uncover how these tissue‐scale regulatory mechanisms are translated to the cellular and molecular level, and how regulation of distinct cellular processes gives rise to an overall defined size. Addressing these questions will help not only to achieve a better understanding of how size is controlled, but also of how tissue size is coordinated with the specification of pattern
The refined best-response correspondence in normal form games
Journal ArticleThis is the author's accepted version of Balkenborg, D., Hofbauer, J., & Kuzmics, C. (2015). The refined best-response correspondence in normal form games. International Journal of Game Theory, 44(1), 165-193. The final publication is available at Springer via http://dx.doi.org/10.1007/s00182-014-0424-zThis paper provides an in-depth study of the (most) refined best-response correspondence introduced by Balkenborg et al. (Theor Econ 8:165–192, 2013). An example demonstrates that this correspondence can be very different from the standard best-response correspondence. In two-player games, however, the refined bestresponse correspondence of a given game is the same as the best-response correspondence of a slightly modified game. The modified game is derived from the original game by reducing the payoff by a small amount for all pure strategies that are weakly inferior. Weakly inferior strategies, for two-player games, are pure strategies that are either weakly dominated or are equivalent to a proper mixture of pure strategies. Fixed points of the refined best-response correspondence are not equivalent to any known Nash equilibrium refinement. A class of simple communication games demonstrates the usefulness and intuitive appeal of the refined best-response correspondence
100 years of farming: long-term differences in cropping intensity and N fertilization impact soil microbial community structure
Non-Peer Reviewe
Signatures of the disk-jet coupling in the Broad-line Radio Quasar 4C+74.26
Here we explore the disk-jet connection in the broad-line radio quasar
4C+74.26, utilizing the results of the multiwavelength monitoring of the
source. The target is unique in that its radiative output at radio wavelengths
is dominated by a moderately-beamed nuclear jet, at optical frequencies by the
accretion disk, and in the hard X-ray range by the disk corona. Our analysis
reveals a correlation (local and global significance of 96\% and 98\%,
respectively) between the optical and radio bands, with the disk lagging behind
the jet by days. We discuss the possible explanation for this,
speculating that the observed disk and the jet flux changes are generated by
magnetic fluctuations originating within the innermost parts of a truncated
disk, and that the lag is related to a delayed radiative response of the disk
when compared with the propagation timescale of magnetic perturbations along
relativistic outflow. This scenario is supported by the re-analysis of the
NuSTAR data, modelled in terms of a relativistic reflection from the disk
illuminated by the coronal emission, which returns the inner disk radius
. We discuss the global energetics in
the system, arguing that while the accretion proceeds at the Eddington rate,
with the accretion-related bolometric luminosity erg s , the jet total kinetic energy
erg s, inferred from the dynamical
modelling of the giant radio lobes in the source, constitutes only a small
fraction of the available accretion power.Comment: 9 pages and 6 figures, ApJ accepte
C-Methylcalix[4]resorcinarene–1,4-bis(pyridin-3-yl)-2,3-diaza-1,3-butadiene (1/2)
In the title compound, 2C12H10N4·C32H32O8, the calixarene adopts a rctt conformation with dihedral angles of 138.40 (1) and 9.10 (1)° between the opposite rings. The dihedral angles between the rings of the pyridine derivative are 8.80 (1) and 9.20 (1)°. In the crystal, adjacent C-methylcalix[4]resorcinarene molecules are connected into columns parallel to [010] by O—H⋯O hydrogen bonds. O—H⋯N hydrogen bonds between the axial phenoxyl groups and bipyridine molecules link the columns into sheets parallel to (011), which are connected by O—H⋯N hydrogen bonds. Further O—H⋯N hydrogen bonds link the bipyridine and C-methylcalix[4]resorcinarene molecules, giving rise to a three-dimensional network
First results of the LARES 2 space experiment to test the general theory of relativity
The LAGEOS 3 (today LARES 2) space experiment was proposed in the eighties by
the Physics Department and by the Center of Space Research (CSR) of the
University of Texas (UT) at Austin and by the Italian Space Agency (ASI) to
test and accurately measure frame-dragging, with the strong support of John
Archibald Wheeler, director of the Center for Theoretical Physics of UT Austin.
Frame-dragging is an intriguing phenomenon predicted by Einstein's theory of
general relativity which has fundamental implications in high energy
astrophysics and in the generation of gravitational waves by spinning black
holes. LAGEOS 3 was reproposed in 2016 to the Italian Space Agency and to the
European Space Agency as a technologically much improved version of LAGEOS 3
under the name LARES 2 (LAres RElativity Satellite 2) and then successfully
launched in 2022 with the new launch vehicle VEGA C of ASI, ESA and AVIO.
Today, after almost forty years since the original proposal, we report the
first results of the LARES 2 space experiment to test general relativity. The
results are in complete agreement with the predictions of Einstein's
gravitational theory. Whereas previous results already confirmed the
frame-dragging prediction, the conceptual relative simplicity of the LARES 2
experiment with respect to the previous tests with the LARES and LAGEOS
satellites provides a significant advance in the field of tests of general
relativity.Comment: 11 page
PERFIL EPIDEMIOLÓGICO DOS PACIENTES POLITRAUMATIZADOS COM PNEUMONIA ASSOCIADA À VENTILAÇÃO MECÂNICA NA UNIDADE DE TERAPIA INTENSIVA DO HOSPITAL UNIVERSITÁRIO EVANGÉLICO DE CURITIBA
Abstract: Purpose: Demonstrate the epidemiological profile of polytrauma patients who developed ventilator-associated pneumonia in the intensive care unit of Evangélico University Hospital from Curitiba. Material and Method: Were assessed patients who developed ventilator-associated pneumonia in the period of March 2012 through September 2012. Were surveyed several factors that could influence the occurrence of the ventilator-associated pneumonia, such as gender, age, comorbidities, duration of mechanical ventilation and length of hospitalization. Results: Forty patients aged between 18 and 73 years, with 28 (70%) males and 12 (30%) female were evaluated in this study. The hospitalization of the patients in the ICU ranged from a minimum of 4 days to a maximum of 111 days with a mean of 19.1 days, the duration of mechanical ventilation ranged from 4 to 111 days with an average of 16 days. Conclusion: The epidemiological profile of polytrauma patients that develops ventilator-associated pneumonia in Evangélico University Hospital from Curitiba demon-strate that this kind of infection predominates in male patients with a mean age of 36 years, smokers, who already make use of mechanical ventilation for at least 16 days and also that infection begins on average in the sixth day following the patient intubation. Resumo: Objetivo: demonstrar o perfil epidemiológico dos pacientes politraumatizados que desenvolveram pneumonia associada à ventilação mecânica na unidade de terapia intensiva do Hospital Universitário Evangélico de Curitiba Materi-al e Método: Foram avaliados os pacientes que desenvolveram pneumonia associada à ventilação mecânica no período de março de 2012 até setembro de 2012, onde foram pesquisados fatores que poderiam influenciar na ocorrência da doença, como sexo, idade, presença de comorbidades, tempo de ventilação mecânica e tempo de internamento. Resultados: Foram avaliados 40 pacientes, com idades entre 18 e 73 anos, sendo 28 (70%) do sexo masculino e 12 (30%) do sexo feminino. O tempo de internação dos pacientes em UTI variou de um mínimo de 4 dias para um máximo de 111 dias, com média de 19,1 dias, o tempo de ventilação mecânica variou de 4 a 111 dias, com média de 16 dias. Conclusão: o perfil epidemiológico do paciente politraumatizado que desenvolve pneumonia associada a ventilação mecânica no Hospital Universitário Evangélico de Curitiba é de pacientes do sexo masculino, com idade média de 36 anos, tabagistas,que já fazem uso de ventilação mecânica por pelo menos 16 dias, sendo que a infecção se inicia em média no sexto dia após a intubação do paciente
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