863 research outputs found
Progress on Complex Langevin simulations of a finite density matrix model for QCD
We study the Stephanov model, which is an RMT model for QCD at finite
density, using the Complex Langevin algorithm. Naive implementation of the
algorithm shows convergence towards the phase quenched or quenched theory
rather than to intended theory with dynamical quarks. A detailed analysis of
this issue and a potential resolution of the failure of this algorithm are
discussed. We study the effect of gauge cooling on the Dirac eigenvalue
distribution and time evolution of the norm for various cooling norms, which
were specifically designed to remove the pathologies of the complex Langevin
evolution. The cooling is further supplemented with a shifted representation
for the random matrices. Unfortunately, none of these modifications generate a
substantial improvement on the complex Langevin evolution and the final results
still do not agree with the analytical predictions.Comment: 8 pages, 7 figures, Proceedings of the 35th International Symposium
on Lattice Field Theory, Granada, Spai
Diagrammatic Monte Carlo study of the acoustic and the BEC polaron
We consider two large polaron systems that are described by a Fr\"{o}hlich
type of Hamiltonian, namely the Bose-Einstein condensate (BEC) polaron in the
continuum and the acoustic polaron in a solid. We present ground-state energies
of these two systems calculated with the Diagrammatic Monte Carlo (DiagMC)
method and with a Feynman all-coupling approach. The DiagMC method evaluates up
to very high order a diagrammatic series for the polaron Green's function. The
Feynman all-coupling approach is a variational method that has been used for a
wide range of polaronic problems. For the acoustic and BEC polaron both methods
provide remarkably similar non-renormalized ground-state energies that are
obtained after introducing a finite momentum cutoff. For the renormalized
ground-state energies of the BEC polaron, there are relatively large
discrepancies between the DiagMC and the Feynman predictions. These differences
can be attributed to the renormalization procedure for the contact interaction.Comment: 9 pages, 10 figure
Strategies To Reconstruct 3d Coffea Arabica L. Plant Structure
Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Accurate model of structural elements is necessary to model the foliage and fruit distributions in cultivated plants, both of them being key parameters for yield prediction. However, the level of details in architectural data collection could vary, simplifying the data collection when plants get older and because of the high time cost required. In the present study, we aimed at reconstructing and analyzing plant structure, berry distributions and yield in Coffea arabica (Arabica coffee), by using both detailed or partial morphological information and probabilistic functions. Different datasets of coffee plant architectures were available with different levels of detail depending on the tree age. Three scales of decomposition-plant, axes and metamers were used reconstruct the plant architectures. CoffePlant3D, a software which integrates a series of mathematical, computational and statistical methods organized in three newly developed modules, AmostraCafe3D, VirtualCafe3D and Cafe3D, was developed to accurately reconstruct coffee plants in 3D, whatever the level of details available. The number of metamers of the 2nd order axes was shown to be linearly proportional to that of the orthotropic trunk, and the number of berries per metamer was modeled as a Gaussian function within a specific zone along the plagiotropic axes. This ratio of metamer emission rhythm between the orthotropic trunk and plagiotropic axes represents the pillar of botanical events in the C. arabica development and was central in our modeling approach, especially to reconstruct missing data. The methodology proposed for reconstructing coffee plants under the CoffePlant3D was satisfactorily validated across dataset available and could be performed for any other Arabica coffee variety.5Brazilian Consorcio Pesquisa Cafe [02.09.20.008.00.03, 02.13.02.042.00.03]CNPq [381241/2014-9]Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq
Glucose-Induced O2 Consumption Activates Hypoxia Inducible Factors 1 and 2 in Rat Insulin-Secreting Pancreatic Beta-Cells
Glucose increases the expression of glycolytic enzymes and other hypoxia-response genes in pancreatic beta-cells. Here, we tested whether this effect results from the activation of Hypoxia-Inducible-factors (HIF) 1 and 2 in a hypoxia-dependent manner
Agrobacterium species bacteraemia, Switzerland, 2008 to 2019: A molecular epidemiological study
BACKGROUND: Agrobacterium spp. are infrequent agents of bloodstream infections linked to healthcare-associated outbreaks. However, it is unclear if outbreaks also occur across larger geographic areas. Triggered by two local clusters from putative point sources, our aim was to detect potential additional clusters in Switzerland.
METHODS: We performed a nationwide descriptive study of cases in Switzerland based on a prospective surveillance system (Swiss Centre for Antibiotic Resistance, anresis.ch), from 2008 to 2019. We identified patients with Agrobacterium spp. isolated from blood cultures and used a survey to collect clinical-epidemiological information and susceptibility testing results. We performed whole genome sequencing (WGS) of available clinical isolates and determined their relatedness by single nucleotide polymorphism (SNP) variant calling analysis.
RESULTS: We identified a total of 36 cases of Agrobacterium spp. from blood samples over 10 years. Beyond previously known local clusters, no new ones were identified. WGS-based typing was performed on 22 available isolates and showed no clonal relationships between newly identified isolates or to those from the known clusters, with all isolates outside these clusters being at least 50 SNPs apart.
CONCLUSION AND RELEVANCE: Agrobacterium spp. bacteraemia is infrequently detected and, given that it may be healthcare-associated and stem from a point source, occurrence of multiple episodes should entail an outbreak investigation. With the help of the national antimicrobial resistance surveillance system we identified multiple clinical cases of this rare pathogen but found no evidence by WGS that suggested a nation-wide outbreak
Agrobacterium species bacteraemia, Switzerland, 2008 to 2019: a molecular epidemiological study.
BACKGROUND
Agrobacterium spp. are infrequent agents of bloodstream infections linked to healthcare-associated outbreaks. However, it is unclear if outbreaks also occur across larger geographic areas. Triggered by two local clusters from putative point sources, our aim was to detect potential additional clusters in Switzerland.
METHODS
We performed a nationwide descriptive study of cases in Switzerland based on a prospective surveillance system (Swiss Centre for Antibiotic Resistance, anresis.ch), from 2008 to 2019. We identified patients with Agrobacterium spp. isolated from blood cultures and used a survey to collect clinical-epidemiological information and susceptibility testing results. We performed whole genome sequencing (WGS) of available clinical isolates and determined their relatedness by single nucleotide polymorphism (SNP) variant calling analysis.
RESULTS
We identified a total of 36 cases of Agrobacterium spp. from blood samples over 10Â years. Beyond previously known local clusters, no new ones were identified. WGS-based typing was performed on 22 available isolates and showed no clonal relationships between newly identified isolates or to those from the known clusters, with all isolates outside these clusters being at least 50 SNPs apart.
CONCLUSION AND RELEVANCE
Agrobacterium spp. bacteraemia is infrequently detected and, given that it may be healthcare-associated and stem from a point source, occurrence of multiple episodes should entail an outbreak investigation. With the help of the national antimicrobial resistance surveillance system we identified multiple clinical cases of this rare pathogen but found no evidence by WGS that suggested a nation-wide outbreak
Epidemiology of subsequent bloodstream infections in the ICU
Abstract Subsequent bloodstream infections (sBSI) occur with a delay after removal of the intravascular catheter (IVC) whose tip revealed microbial growth. Here we describe the epidemiology of sBSI in the intensive care setting. Serratia marcescens, Staphylococcus aureus, Pseudomonas aeruginosa, and yeast were the pathogens most frequently associated with sBSI. In contrast, Enterococci were rarely found in sBSI
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