271 research outputs found
25 years of tillage effects on wheat production in a continuous cropping system
Non-Peer ReviewedHeat stress occurs often in wheat on the Canadian Prairies especially during grain growth (from anthesis to maturity), which has a markedly negative impact on yield (McCaig 1997). Under no-till management (NT), surface residue and stubble act as insulation and impede the exchange rate of thermal energy between the soil and the atmosphere, and the superior soil moisture of NT compared to conventional tillage (CT) can buffer the extremes in daily soil temperatures. It is, therefore, possible that the cooling effect of NT could alleviate the root heat stress of wheat. Under a continuous wheat cropping system on a Thin Black Chernozemic clay loam in central Alberta, Wang et al (2007) found that the near-surface soil temperature of NT was
lower than that of CT throughout the growing season, which reduced the risk of root heat stress and benefited grain yield and biomass. The objective of this study was to investigate whether a similar effect of NT is present in southwestern Saskatchewan
Structure of even-even nuclei using a mapped collective Hamiltonian and the D1S Gogny interaction
A systematic study of low energy nuclear structure at normal deformation is
carried out using the Hartree-Fock-Bogoliubov theory extended by the Generator
Coordinate Method and mapped onto a 5-dimensional collective quadrupole
Hamiltonian. Results obtained with the Gogny D1S interaction are presented from
dripline to dripline for even-even nuclei with proton numbers Z=10 to Z=110 and
neutron numbers N less than 200. The properties calculated for the ground
states are their charge radii, 2-particle separation energies, correlation
energies, and the intrinsic quadrupole shape parameters. For the excited
spectroscopy, the observables calculated are the excitation energies and
quadrupole as well as monopole transition matrix elements. We examine in this
work the yrast levels up to J=6, the lowest excited 0^+ states, and the two
next yrare 2^+ states. The theory is applicable to more than 90% of the nuclei
which have tabulated measurements. The data set of the calculated properties of
1712 even-even nuclei, including spectroscopic properties for 1693 of them, are
provided in CEA website and EPAPS repository with this article \cite{epaps}.Comment: 51 pages with 26 Figures and 4 internal tables; this version is
accepted by Physical Review
An Exact Chiral Amorphous Spin Liquid
Topological insulator phases of non-interacting particles have been
generalized from periodic crystals to amorphous lattices, which raises the
question whether topologically ordered quantum many-body phases may similarly
exist in amorphous systems? Here we construct a soluble chiral amorphous
quantum spin liquid by extending the Kitaev honeycomb model to random lattices
with fixed coordination number three. The model retains its exact solubility
but the presence of plaquettes with an odd number of sides leads to a
spontaneous breaking of time reversal symmetry. We unearth a rich phase diagram
displaying Abelian as well as a non-Abelian quantum spin liquid phases with a
remarkably simple ground state flux pattern. Furthermore, we show that the
system undergoes a finite-temperature phase transition to a conducting thermal
metal state and discuss possible experimental realisations.Comment: 5 pages, 3 figure
Microscopic Observation Drug Susceptibility Assay for Rapid Diagnosis of Lymph Node Tuberculosis and Detection of Drug Resistance.
In this study, 132 patients with lymphadenopathy were investigated. Fifty-two (39.4%) were diagnosed with tuberculosis (TB). The microscopic observation drug susceptibility (MODS) assay provided rapid (13 days), accurate diagnosis (sensitivity, 65.4%) and reliable drug susceptibility testing (DST). Despite its lower sensitivity than that of other methods, its faster results and simultaneous DST are advantageous in resource-poor settings, supporting the incorporation of MODS into diagnostic algorithms for extrapulmonary TB
Linear Responses in Time-dependent Hartree-Fock-Bogoliubov Method with Gogny Interaction
A numerical method to integrate the time-dependent Hartree-Fock Bogoliubov
(TDHFB) equations with Gogny interaction is proposed. The feasibility of the
TDHFB code is illustrated by the conservation of the energy, particle numbers,
and center-of-mass in the small amplitude vibrations of oxygen 20. The TDHFB
code is applied to the isoscalar quadrupole and/or isovector dipole vibrations
in the linear (small amplitude) region in oxygen isotopes (masses A = 18,20,22
and 24), titanium isotopes (A = 44,50,52 and 54), neon isotope (A = 26), and
magnesium isotopes (A = 24 and 34). The isoscalar quadrupole and isovector
dipole strength functions are calculated from the expectation values of the
isoscalar quadrupole and isovector dipole moments.Comment: 10 pages, 13 figure
Spin-orbit splitting and the tensor component of the Skyrme interaction
We study the role of the tensor term of the Skyrme effective interactions on
the spin-orbit splittings in the N=82 isotones and Z=50 isotopes. The different
role of the triplet-even and triplet-odd tensor forces is pointed out by
analyzing the spin-orbit splittings in these nuclei. The experimental isospin
dependence of these splittings cannot be described by Hartree-Fock calculations
employing the usual Skyrme parametrizations, but is very well accounted for
when the tensor interaction is introduced. The capability of the Skyrme forces
to reproduce binding energies and charge radii in heavy nuclei is not destroyed
by the introduction of the tensor term. Finally, we also discuss the effect of
the tensor force on the centroid of the Gamow-Teller states.Comment: Submitted to Phys. Lett.
Seizures, cysticercosis and rural-to-urban migration: the PERU MIGRANT study.
OBJECTIVES: To examine the prevalence of seizures, epilepsy and seropositivity to cysticercosis in rural villagers (cysticercosis-endemic setting), rural-to-urban migrants into a non-endemic urban shanty town and urban inhabitants of the same non-endemic shanty town. METHODS: Three Peruvian populations (n = 985) originally recruited into a study about chronic diseases and migration were studied. These groups included rural inhabitants from an endemic region (n = 200), long-term rural-to-urban migrants (n = 589) and individuals living in the same urban setting (n = 196). Seizure disorders were detected by a survey, and a neurologist examined positive respondents. Serum samples from 981/985 individuals were processed for cysticercosis antibodies on immunoblot. RESULTS: Epilepsy prevalence (per 1000 people) was 15.3 in the urban group, 35.6 in migrants and 25 in rural inhabitants. A gradient in cysticercosis antibody seroprevalence was observed: urban 2%, migrant 13.5% and rural group 18% (P < 0.05). A similarly increasing pattern of higher seroprevalence was observed among migrants by age at migration. In rural villagers, there was strong evidence of an association between positive serology and having seizures (P = 0.011) but such an association was not observed in long-term migrants or in urban residents. In the entire study population, compared with seronegative participants, those with strong antibody reactions (≥ 4 antibody bands) were more likely to have epilepsy (P < 0.001). CONCLUSIONS: It is not only international migration that affects cysticercosis endemicity; internal migration can also affect patterns of endemicity within an endemic country. The neurological consequences of cysticercosis infection likely outlast the antibody response for years after rural-to-urban migration
Human Colon Microbiota Transform Polycyclic Aromatic Hydrocarbons to Estrogenic Metabolites
Ingestion is an important exposure route for polycyclic aromatic hydrocarbons (PAHs) to enter the human body. Although the formation of hazardous PAH metabolites by human biotransformation enzymes is well documented, nothing is known about the PAH transformation potency of human intestinal microbiota. Using a gastrointestinal simulator, we show that human intestinal microbiota can also bioactivate PAHs, more in particular to estrogenic metabolites. PAH compounds are not estrogenic, and indeed, stomach and small intestine digestions of 62.5 nmol naphthalene, phenanthrene, pyrene, and benzo(a)pyrene showed no estrogenic effects in the human estrogen receptor bioassay. In contrast, colon digests of these PAH compounds displayed estrogenicity, equivalent to 0.31, 2.14, 2.70, and 1.48 nmol 17α-ethynylestradiol (EE2), respectively. Inactivating the colon microbiota eliminated these estrogenic effects. Liquid chromatography–mass spectrometry analysis confirmed the microbial PAH transformation by the detection of PAH metabolites 1-hydroxypyrene and 7-hydroxybenzo(a)pyrene in colon digests of pyrene and benzo(a)pyrene. Furthermore, we show that colon digests of a PAH-contaminated soil (simulated ingestion dose of 5 g/day) displayed estrogenic activity equivalent to 0.58 nmol EE2, whereas stomach or small intestine digests did not. Although the matrix in which PAHs are ingested may result in lower exposure concentrations in the gut, our results imply that the PAH bioactivation potency of colon microbiota is not eliminated by the presence of soil. Moreover, because PAH toxicity is also linked to estrogenicity of the compounds, the PAH bioactivation potency of colon microbiota suggests that current risk assessment may underestimate the risk from ingested PAHs
Dynamics of Cough Frequency in Adults Undergoing Treatment for Pulmonary Tuberculosis.
Background: Cough is the major determinant of tuberculosis transmission. Despite this, there is a paucity of information regarding characteristics of cough frequency throughout the day and in response to tuberculosis therapy. Here we evaluate the circadian cycle of cough, cough frequency risk factors, and the impact of appropriate treatment on cough and bacillary load. Methods: We prospectively evaluated human immunodeficiency virus-negative adults (n = 64) with a new diagnosis of culture-proven, drug-susceptible pulmonary tuberculosis immediately prior to treatment and repeatedly until treatment day 62. At each time point, participant cough was recorded (n = 670) and analyzed using the Cayetano Cough Monitor. Consecutive coughs at least 2 seconds apart were counted as separate cough episodes. Sputum samples (n = 426) were tested with microscopic-observation drug susceptibility broth culture, and in culture-positive samples (n = 252), the time to culture positivity was used to estimate bacillary load. Results: The highest cough frequency occurred from 1 pm to 2 pm, and the lowest from 1 am to 2 am (2.4 vs 1.1 cough episodes/hour, respectively). Cough frequency was higher among participants who had higher sputum bacillary load (P < .01). Pretreatment median cough episodes/hour was 2.3 (interquartile range [IQR], 1.2-4.1), which at 14 treatment days decreased to 0.48 (IQR, 0.0-1.4) and at the end of the study decreased to 0.18 (IQR, 0.0-0.59) (both reductions P < .001). By 14 treatment days, the probability of culture conversion was 29% (95% confidence interval, 19%-41%). Conclusions: Coughs were most frequent during daytime. Two weeks of appropriate treatment significantly reduced cough frequency and resulted in one-third of participants achieving culture conversion. Thus, treatment by 2 weeks considerably diminishes, but does not eliminate, the potential for airborne tuberculosis transmission
A review of the MSCA ITN ECOSTORE - Novel complex metal hydrides for efficient and compact storage of renewable energy as hydrogen and electricity
Hydrogen as an energy carrier is very versatile in energy storage applications. Developments in novel, sustainable technologies towards a CO2-free society are needed and the exploration of all-solid-state batteries (ASSBs) as well as solid-state hydrogen storage applications based on metal hydrides can provide solutions for such technologies. However, there are still many technical challenges for both hydrogen storage material and ASSBs related to designing low-cost materials with low-environmental impact. The current materials considered for all-solid-state batteries should have high conductivities for Na+, Mg2+ and Ca2+, while Al3+-based compounds are often marginalised due to the lack of suitable electrode and electrolyte materials. In hydrogen storage materials, the sluggish kinetic behaviour of solid-state hydride materials is one of the key constraints that limit their practical uses. Therefore, it is necessary to overcome the kinetic issues of hydride materials before discussing and considering them on the system level. This review summarizes the achievements of the Marie Skłodowska-Curie Actions (MSCA) innovative training network (ITN) ECOSTORE, the aim of which was the investigation of different aspects of (complex) metal hydride materials. Advances in battery and hydrogen storage materials for the efficient and compact storage of renewable energy production are discussed
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