2,544 research outputs found
Sunn Hemp as an Alternative Forage in the Texas High Plains Region
Forage production in the Texas High Plains, a semi-arid region, is critical to sustain the local cattle industry. However, the main source of water for irrigation is the highly depleted Ogallala Aquifer, making forage crop water productivity (CWP) of high importance. In this one-year study, three types of forages were cultivated under deficit irrigation treatments of 80% and 50% of full crop water use. The forages were: a non-brown midrib forage sorghum; a legume, sunn hemp; and a sorghum/sunn hemp mix. The experiment was conducted in Bushland, Texas in 2019. Treatment plots were arranged in a split plot design with four replications under a 6-span variable rate irrigation center pivot sprinkler. Above ground biomass samples were taken by hand from a 1 m2 quadrat in each of the 24 plots on Jul 23, Aug 6 for forage analysis, and on Aug 19 to assess biomass yield and CWP. Crude protein was significantly higher at the first and second cuttings in the sunn hemp monocrop, but not significantly different between irrigation levels. The final biomass yields and CWP were similar between the sorghum (23.6 Mg ha-1) and sorghum/sunn hemp (25.1 Mg ha-1) forages, irrespective of irrigation level. The sunn hemp monocrop produced significantly lower biomass (9.75 Mg ha-1), which reduced CWP
Global existence and asymptotic behaviour in the future for the Einstein-Vlasov system with positive cosmological constant
The behaviour of expanding cosmological models with collisionless matter and
a positive cosmological constant is analysed. It is shown that under the
assumption of plane or hyperbolic symmetry the area radius goes to infinity,
the spacetimes are future geodesically complete, and the expansion becomes
isotropic and exponential at late times. This proves a form of the cosmic no
hair theorem in this class of spacetimes
Plasmon Evolution and Charge-Density Wave Suppression in Potassium Intercalated Tantalum Diselenide
We have investigated the influence of potassium intercalation on the
formation of the charge-density wave (CDW) instability in 2H-tantalum
diselenide by means of Electron Energy-Loss Spectroscopy and density functional
theory. Our observations are consistent with a filling of the conduction band
as indicated by a substantial decrease of the plasma frequency in experiment
and theory. In addition, elastic scattering clearly points to a destruction of
the CDW upon intercalation as can be seen by a vanishing of the corresponding
superstructures. This is accompanied by a new superstructure, which can be
attributed to the intercalated potassium. Based on the behavior of the c-axis
upon intercalation we argue in favor of interlayer-sites for the alkali-metal
and that the lattice remains in the 2H-modification
Matrix-free calcium in isolated chromaffin vesicles
Isolated secretory vesicles from bovine adrenal medulla contain 80 nmol of Ca2+ and 25 nmol
of Mg2+ per milligram of protein. As determined with a Ca2+-selective electrode, a further accumulation
of about 160 nmol of Ca2+/mg of protein can be attained upon addition of the Ca2+ ionophore A23187.
During this process protons are released from the vesicles, in exchange for Ca2+ ions, as indicated by the
decrease of the pH in the incubation medium or the release of 9-aminoacridine previously taken up by the
vesicles. Intravesicular Mg2+ is not released from the vesicles by A23 187, as determined by atomic emission
spectroscopy. In the presence of N H Q , which causes the collapse of the secretory vesicle transmembrane
proton gradient (ApH), Ca2+ uptake decreases. Under these conditions A23 187-mediated influx of Ca2+
and efflux of H+ cease at Ca2+ concentrations of about 4 pM. Below this concentration Ca2+ is even released
from the vesicles. At the Ca2+ concentration at which no net flux of ions occurs the intravesicular matrix
free Ca2+ equals the extravesicular free Ca2+. In the absence of NH4C1 we determined an intravesicular
pH of 6.2. Under these conditions the Ca2+ influx ceases around 0.15 pM. From this value and the known
pH across the vesicular membrane an intravesicular matrix free Ca2+ concentration of about 24 pM was
calculated. This is within the same order of magnitude as the concentration of free Ca2+ in the vesicles
determined in the presence of NH4C1. Calculation of the total Ca2+ present in the secretory vesicles gives
an apparent intravesicular Ca2+ concentration of 40 mM, which is a factor of lo4 higher than the free
intravesicular concentration of Ca2+. It can be concluded, therefore, that the concentration gradient of free
Ca2+ across the secretory vesicle membrane in the intact chromaffin cells is probably small, which implies
that less energy is required to accumulate and maintain Ca2+ within the vesicles than was previously
anticipated
Empirical logic of finite automata: microstatements versus macrostatements
We compare the two approaches to the empirical logic of automata. The first,
called partition logic (logic of microstatements), refers to experiments on
individual automata. The second one, the logic of simulation (logic of
macrostatements), deals with ensembles of automata.Comment: late
On centralizer algebras for spin representations
We give a presentation of the centralizer algebras for tensor products of
spinor representations of quantum groups via generators and relations. In the
even-dimensional case, this can be described in terms of non-standard
q-deformations of orthogonal Lie algebras; in the odd-dimensional case only a
certain subalgebra will appear. In the classical case q = 1 the relations boil
down to Lie algebra relations
“In small places, close to home”: urban environmental impacts on child rights across four global cities
Urban environments influence child behaviours, exposures and experiences and may affect health, development, achievement and realization of fundamental human rights. We examined the status of eleven UN Convention on the Rights of the Child articles, in a multi-case study across four global cities. Within all study cities, children experienced unequal exposure to urban environmental risks and amenities. Many violations of child rights are related to car-based transportation systems and further challenged by pressures on urban systems from rapid population increases in the context of climate change. A child rights framework provides principles for a collective, multi-sectoral re-imagination of urban environments that support the human rights of all citizens
Childhood intermittent and persistent rhinitis prevalence and climate and vegetation: A global ecologic analysis
Background: The effect of climate change and its effects on vegetation growth, and consequently on rhinitis,are uncertain.Objective: To examine between- and within-country associations of climate measures and the normalizeddifference vegetation index with intermittent and persistent rhinitis symptoms in a global context.Methods: Questionnaire data from 6- to 7-year-olds and 13- to 14-year-olds were collected in phase 3 of theInternational Study of Asthma and Allergies in Childhood. Associations of intermittent (>1 symptom reportbut not for 2 consecutive months) and persistent (symptoms for -2 consecutive months) rhinitis symptomprevalences with temperature, precipitation, vapor pressure, and the normalized difference vegetation indexwere assessed in linear mixed-effects regression models adjusted for gross national income and populationdensity. The mean difference in prevalence per 100 children (with 95% confidence intervals [CIs]) perinterquartile range increase of exposure is reported.Results: The country-level intermittent symptom prevalence was associated with several country-levelclimatic measures, including the country-level mean monthly temperature (6.09-C; 95% CI, 2.06e10.11-C per 10.4-C), precipitation (3.10 mm; 95% CI, 0.46e5.73 mm; per 67.0 mm), and vapor pressure(6.21 hPa; 95% CI, 2.17e10.24 hPa; per 10.4 hPa) among 13- to 14-year-olds (222 center in 94 countries).The center-level persistent symptom prevalence was positively associated with several center-level climaticmeasures. Associations with climate were also found for the 6- to 7-year-olds (132 center in 57countries).Conclusion: Several between- and within-country spatial associations between climatic factors and intermittentand persistent rhinitis symptom prevalences were observed. These results provide suggestive evidencethat climate (and future changes in climate) may influence rhinitis symptom prevalence
Inductive localization accuracy of a passive 3-D coil in an Industry 4.0 environment
In this paper a localization system of a passive 3-D coil is
proposed and signal uncertainties due to the 3-D coil's arbitrary orientation
are analyzed. The 3-D coil is excited by an alternating primary magnetic
field. Geometrically distributed pick-up coils measure the 3-D coil's
secondary field. By means of a simulated look-up table that assigns expected
voltages from the pick-up coils to the positions of the 3-D coil, the
position of the 3-D coil is deduced by a least-squares approach. A basic
assumption is that the secondary field is invariant to the orientation of the
3-D coil. This allows a reduction of the computational effort for the look-up
table generation and the table search during the localization phase since for
each position the field distribution for only one orientation has to be
calculated. However, the assumption of invariance to rotation is only valid
for a dipole model. In this paper we investigate the localization error
introduced by this assumption when using 3-D coils with a geometric extent in
an inhomogeneous primary field. Optimized localization methods that decrease
the statistical error are proposed. The theoretical results are verified with
measurements conducted on a laboratory system.</p
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