436 research outputs found
Turbulence-generated proton-scale structures in the terrestrial magnetosheath
Recent results of numerical magnetohydrodynamic simulations suggest that in
collisionless space plasmas turbulence can spontaneously generate thin current
sheets. These coherent structures can partially explain intermittency and the
non-homogenous distribution of localized plasma heating in turbulence. In this
Letter Cluster multi-point observations are used to investigate the
distribution of magnetic field discontinuities and the associated small-scale
current sheets in the terrestrial magnetosheath downstream of a quasi-parallel
bow shock. It is shown experimentally, for the first time, that the strongest
turbulence generated current sheets occupy the long tails of probability
distribution functions (PDFs) associated with extremal values of magnetic field
partial derivatives. During the analyzed one hour long time interval, about a
hundred strong discontinuities, possibly proton-scale current sheets were
observed.Comment: 10 pages, 5 figures in The Astrophysical Journal Letters, Volume 819,
Number 1, 201
Multifractal structure of turbulence in the magnetospheric cusp
Magnetospheric cusps are regions which are characterized by highly turbulent plasma. We have used Polar magnetic field data to study the structure of turbulence in the cusp region. The wavelet transform modulus maxima method (WTMM) has been applied to estimate the scaling exponent of the partition function and singularity spectra. Their features are similar to those found in the nonlinear multifractal systems. We have found that the scaling exponent does not allow one to conclude which intermittency model fits the experiment better. However, the singularity spectra reveal that different models can be ascribed to turbulence observed under various IMF conditions. For northward IMF conditions the turbulence is consistent with the multifractal <i>p</i>-model of fully developed fluid turbulence. For southward IMF experimental data agree with the model of non-fully developed Kolmogorov-like fluid turbulence
Determining the verse of magnetic turbulent cascades in the Earth's magnetospheric cusp via transfer entropy analysis: preliminary results
International audienceThe inter-scale coupling in the dynamics of the magnetic field in the Earth's magnetospheric cusp is studied with the technique of transfer entropy. This is a non-linear data analysis technique conceived to determine which is the process that plays the role of the "dynamical driver" between two processes interacting. The time series of the magnetic field components measured along the trajectory of a spacecraft through the cusp are decomposed via continuous wavelets, so a time series of the square modulus of the wavelet coefficients may be associated to each scale ? considered. The coupling between to two nearby scales is studied, with the purpose of singling out turbulent cascade directions from large to small scales and viceversa. Preliminary physical conclusions are proposed
Caixa Geral de Depósitos (Portugal) and TechnoLogica (Bulgaria): analysing companies' Corporate Social Responsibility in two European countries
The studies in the area of Corporate Social Responsibility are very relevant to understand why companies are concerned with its implementation in the company. Besides, theoretical developments on this matter show that progressively companies are concerned about their performance on this subject and about reaching their objectives involving CSR. Corporate Social Responsibility should have self-regulating mechanisms through which the business would be monitored and companies should be ensure that law is guaranteed as far as ethical standards and international norms. According to the 2001 European Commission Green Paper, Social Responsibility conceptualization is associated with the idea of companies deciding, in a voluntary base, to contribute for a fair society and a cleaner environment. Caixa Geral de Depósitos (Portugal) and TechnoLogica (Bulgaria) are important companies concerned with the development of CSR activities and have some very interesting results in this area
Effect of foliar products on the inflorescence yield of lavender and essential oil
Received: January 25th, 2022 ; Accepted: May 1st, 2022 ; Published: May 23rd, 2022 ;
Correspondence: [email protected] topic of the effect of foliar fertilization on the productivity and oil content of
lavender is relevant, but not sufficiently studied. The present study aims to establish the effect of
foliar products on the growth, development and productivity of lavender. The field experiment
was carried out at the Agricultural University - Plovdiv with lavender of ‘Jubileina’ variety during
2019–2020. The following variants were included in the study: 1. Untreated control; 2. Treatment
with Fertileader Gold (FG) - 3 L ha-1; 3. Treatment with Fertiactyl Trium + Fertileader Vital
(FT + FVital) - 1.5 + 1.5 L ha-1; 4. Treatment with Fertileader Viti (FViti) - 3 L ha-1; 5. Treatment
with Fertileader Vital (FV) - 3 L ha-1; 6. Treatment with Fertileader Alpha (FA) - 3 L ha-1. Those
preparations are bio stimulants for foliar application. The treatments were made in two
consecutive lavender vegetation seasons. The first application was carried out in the second
growing season (2019) and the second in the next, third growing season (2020). The foliar
application of all tested products increased the photosynthetic activity, but it was better expressed
when using the plant nutrition products FV, FViti and FT + FVital. A positive effect was also
observed in the height and diameter of the bush, but during the third vegetation period. The
number of flowering stems increased by 62.9%; 59.4%; 53.3% and 8.4%, respectively, when
applying the fertilizers FG, FT + FVital, FViti and FV. The application of FG and FT + FVital
increased the yield of fresh inflorescences by 6.1% and 3.7%. The application of the different
products affected the oil yield in different ways; the application of FG, FT + FVital and FViti
increased it, while FV and FA decreased it by 27 kg ha-1 and 16 kg ha-1, respectively, for the first
vegetation and by 43.4 kg ha-1and 33.1 kg ha-1 for the second vegetation. The boron containing
products FG, FT + FVital and FViti led to a significant increase in the essential oil yield, while
the application of the foliar fertilizers FV and FA reduced it. Based on those results, the first three
products are recommended
Optical measurements of electrophoretic suspension kinetics
Electrophoretic deposition (EPD) was originally used for formation of coatings, e. g. in the automotive industry.
Recently EPD is successfully utili
zed for thin film preparation with an app
lication in the optics and electronics. This
paper investigates the process of the suspension formation and aggregation by ultraviolet and visible spectroscopy (UV-
VIS) spectroscopy and Dynamic Light Scattering (DLS) methods. The suspensions were formed by a precipitation of
solution of poly[2-methoxy-5-(3
′
,7
′
-dimethyloctyloxy)-1,4-phenylenevinylene]
in toluene using acetonitrile as a
precipitator. It could be concluded that the progressive suspension particle growth observed by DLS affects regularly
the first derivative of the UV-VIS spectra. By a comparison of the results obtained by both methods it could be seen that
UV-VIS spectroscopy combined with the
spline method could be successfully used
for an estimation of electrophoretic
suspensions
Kinetic Generation of Whistler Waves in the Turbulent Magnetosheath
The Earth's magnetosheath (MSH) is governed by numerous physical processes which shape the particle velocity distributions and contribute to the heating of the plasma. Among them are whistler waves which can interact with electrons. We investigate whistler waves detected in the quasi-parallel MSH by NASA's Magnetospheric Multiscale mission. We find that the whistler waves occur even in regions that are predicted stable to wave growth by electron temperature anisotropy. Whistlers are observed in ion-scale magnetic minima and are associated with electrons having butterfly-shaped pitch-angle distributions. We investigate in detail one example and, with the support of modeling by the linear numerical dispersion solver Waves in Homogeneous, Anisotropic, Multicomponent Plasmas, we demonstrate that the butterfly distribution is unstable to the observed whistler waves. We conclude that the observed waves are generated locally. The result emphasizes the importance of considering complete 3D particle distribution functions, and not only the temperature anisotropy, when studying plasma wave instabilities.Peer reviewe
IN VITRO ASSESMENT OF 0.2 % ZINC-HYALURONATE ACTIVITY AGAINST MICROORGANISMS ISOLATED FROM PATIENTS WITH DIFFICULT HEALING LEG ULCERS
ABSTRACT The development of wound infection and selection of resistant microorganisms is a significant problem in the proces
Restaging role of 18F-FDG-PET/CT in a patient with a Malignant Peripheral Nerve Sheath Tumor (MPNST) caused by neurofibromatosis – case report
Malignant Peripheral Nerve Sheath Tumors (MPNST) are a malignant disease that originates in the cells that cover and protect the peripheral nerves. They are a rare disease, accounting for 6% of soft tissue sarcomas. We present a patient with a malignant peripheral nerve sheath tumor on the left brachium with neurofibromatosis. The patient underwent whole body PET/CT for restaging after total extirpation of a tumor formation originated from n. musculocutaneous in 09.2017, an excision of a recurrent tumor formation in the proximal half of the brachium invading into m. biceps brachii in 12.2017, a performed MRI in 02.2018 - with data for multiple MPSNT in the area between the two previous operations - and subsequent definitive radiotherapy (boost) in the area of the tumor formation and 6 cycles of chemotherapy with Epirubicin. After restaging PET/CT scan of the whole body was performed, progression of the disease was defined - increased in size and activity subpleural lesion in the lower lobe of the right lung
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