2,312 research outputs found
Economic and environmental analysis of the introduction of legumes in livestock farming systems
Legumes in low input systems are becoming increasingly important. The socioeconomic implication of the adoption of novel legumes species has been assessed in sheep and dairy cattle grazing systems in Europe using a biological model which has been linked to linear programming models. In the economic sub-model, the mathematical programming models produce an economic evaluation of the legumes in a farming system context, emphasising the land allocation and the availability of nutrients during the different seasons of the production cycle. Then the paper evaluates the impact of adopting the legumes on the regional income and production. In the UK and Germany, the introduction of legumes results in sizeable gains for the farmers whereas in Italy and France the gains are smaller
Magnetic Control of Transmission and Helicity of Nano-Structured Optical Beams in Magnetoplasmonic Vortex Lenses
We theoretically investigate the generation of far-field propagating optical
beams with a desired orbital angular momentum by using an archetypical
magnetoplasmonic tip surrounded by a gold spiral slit. The use of a magnetic
material can lead to important implications once magneto-optical activity is
activated through the application of an external magnetic field. The physical
model and the numerical study presented here introduce the concept of
magnetically tunable plasmonic vortex lens, namely a magnetoplasmonic vortex
lens, which ensures a tunable selectivity in the polarization state of the
generated nanostructured beam. The presented system provides a promising
platform for a localized excitation of plasmonic vortices followed by their
beaming in the far-field with an active modulation of both light's
transmittance and helicity
Le couplage phosphore-phosphore dans l'adenosine di- et triphosphate
AbstractThe pH dependence of spin-spin coupling constants JP-O-P of ADP and ATP has been determined from the phosphorus NMR spectra at 0°. The variation curves have been interpreted as titration curves. These give different pK values. Comparison with the tripolyphosphate shows the existence of triphosphate chain structural deformation in the nucleotides
Exploring the effects of increasing underutilized crops on consumers’ diets: The case of millet in Uganda
Known in the literature as underutilized, neglected or orphan crops, these crops have been cited as having the potential to improve food and nutritional security. The literature also highlights however that consumers in developing countries are increasingly abandoning their traditional diets that these crops are part of, and are replacing them by western diets. In this context, the purpose of this paper is to investigate the consumption and nutritional implications of expanding the participation of underutilized crops in current diets. This was done using a modified version of the microeconomic consumer problem. This was augmented with a linear constraint using generalized rationing theory that can be found in the economics literature. The method was applied to the case study of the consumption of millet (finger millet, botanical name: Eleusine coracana) by rural, urban-poor and urban-affluent Ugandan socioeconomic groups. The results indicated that millet could contribute to improving the intake of macronutrients and of some micronutrients, though the overall picture is complex. However, under current preferences and given its demand inelasticity, to achieve a substantial increase in the quantity of millet in the diet will require a significant reduction of its price. Otherwise, the net impact on nutrition as measured by the mean adequacy ratio will be only slightly positive for rural and urban-poor households. Our findings indicate that supply-side initiatives aimed at increasing the productivity of underutilized crops (reducing crop price) are likely to produce disappointing results in restoring their importance unless accompanied by specific interventions to expand demand. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40100-021-00206-3
Effect of position on intracranial pressure and compliance: a cross-sectional study including 101 patients
OBJECTIVE: A better understanding of the effect of position on intracranial pressure (ICP) and compliance is important for the development of treatment strategies that can restore normal cerebrospinal fluid (CSF) dynamics. There is limited knowledge on the effect of position on intracranial compliance. In this cross-sectional study the authors tested the association of pulse amplitude (PA) with position and the day/night cycle. Additionally, they describe the postural ICP and PA changes of patients with “normal” ICP dynamics. METHODS: This single-center retrospective study included patients with suspected and/or confirmed CSF dynamics abnormalities who had been examined with elective 24-hour ICP monitoring between October 2017 and September 2019. Patients had been enrolled in a short exercise battery including four positions: supine, lumbar puncture position in the left lateral decubitus position, sitting, and standing. Each position was maintained for 2 minutes, and mean ICP and PA were calculated for each position. The 24-hour day and night median ICP and PA data were also collected. Linear regression models were used to test the correlation of PA with position and day/night cycle. All linear regressions were corrected for confounders. The postural ICP monitoring results of patients without obvious ICP dynamics abnormality were summarized. RESULTS: One hundred one patients (24 males and 77 females) with a mean age of 39 ± 13years (mean ± standard deviation) were included in the study. The adjusted linear regression models demonstrated a significant association of ICP with position and day/night cycle, with upright (sitting and standing) and day ICP values lower than supine and night ICP values. The adjusted linear regression model was also significant for the association of PA with position and day/night cycle, with upright and day PA values higher than supine and night PA results. These associations were confirmed for patients with and without shunts. Patients without clear ICP dynamics abnormality had tighter control of their postural ICP changes than the other patients; however, the difference among groups was not statistically significant. CONCLUSIONS: This is the largest study investigating the effect of postural changes on intracranial compliance. The results of this study suggest that PA, as well as ICP, is significantly associated with posture, increasing in upright positions compared to that while supine. Further studies will be needed to investigate the mechanism behind this association
Multi-line Stokes inversion for prominence magnetic-field diagnostics
We present test results on the simultaneous inversion of the Stokes profiles
of the He I lines at 587.6 nm (D_3) and 1083.0 nm in prominences (90-deg
scattering). We created datasets of synthetic Stokes profiles for the case of
quiescent prominences (B<200 G), assuming a conservative value of 10^-3 of the
peak intensity for the polarimetric sensitivity of the simulated observations.
In this work, we focus on the error analysis for the inference of the magnetic
field vector, under the usual assumption that the prominence can be assimilated
to a slab of finite optical thickness with uniform magnetic and thermodynamic
properties. We find that the simultaneous inversion of the two lines
significantly reduces the errors on the inference of the magnetic field vector,
with respect to the case of single-line inversion. These results provide a
solid justification for current and future instrumental efforts with multi-line
capabilities for the observations of solar prominences and filaments.Comment: 14 pages, 5 figures, 1 tabl
Open and / or laparoscopic surgical treatment of liver hydatic cysts
Hydatid disease is a severe parasitic disease with a widely ranging distribution. In the human being the liver is the most frequent organ affected. 1 The treatment should be individualized to the morphology, size, number and location of the cysts, that is why a variety of surgical operations have been advocated from complete resection like total pericystectomy or partial hepatectomy to laparoscopy to a minimally invasive procedures like percutaneous aspiration of cysts to conservative drug therapy. 3-4 This study compares laparoscopic versus open management of the hydatid cyst of liver the surgical approach to liver echinococcosis is still a controversial issue and shows our results of surgical treatment of liver hydatid cysts during a 3-years period
Uni-directional transport properties of a serpent billiard
We present a dynamical analysis of a classical billiard chain -- a channel
with parallel semi-circular walls, which can serve as a model for a bended
optical fiber. An interesting feature of this model is the fact that the phase
space separates into two disjoint invariant components corresponding to the
left and right uni-directional motions. Dynamics is decomposed into the jump
map -- a Poincare map between the two ends of a basic cell, and the time
function -- traveling time across a basic cell of a point on a surface of
section. The jump map has a mixed phase space where the relative sizes of the
regular and chaotic components depend on the width of the channel. For a
suitable value of this parameter we can have almost fully chaotic phase space.
We have studied numerically the Lyapunov exponents, time auto-correlation
functions and diffusion of particles along the chain. As a result of a
singularity of the time function we obtain marginally-normal diffusion after we
subtract the average drift. The last result is also supported by some
analytical arguments.Comment: 15 pages, 9 figure (19 .(e)ps files
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