214 research outputs found
Sheep and Horse Grazing in a Large-Scale Protection Area and its Positive Impact on Chemical and Biological Soil Properties
This paper looks into the impact of free grazing by sheep and horses on the chemical and biological properties of soils in the partial protection zone of the Roztocze National Park. The study sampled three different types of pastureland in the area: pastures for sheep, horses and for combined grazing by sheep and horses. Compared to an ungrazed reference pasture, free grazing significantly stimulated the activity of enzymes which catalyze the transformation of organic matter (dehydrogenases, phosphatases and ureases) and it also positively influenced other chemical properties of the soils. Among the soils under free-grazing management, the pasture grazed to horses underwent the most advantageous changes in terms of the eco-chemical status of the soil
Model of Enterpreneurship and Social-cultural and Market Orientation of Small Business Owners in Poland
In the development of SMEs in Poland crucial meaning is legislation, steadily adapted to EU regulations, especially to the European Charter for Small Enterprises. Research conducted in Poland by many authors provide data for doing so, to confirm the hypothesis that among small businesses a vital role in shaping their work situation did not continue to play the market mechanisms and orientations, but mainly socio-cultural factors.W rozwoju MŚP w Polsce podstawowe znaczenie mają również uregulowania prawne, systematycznie dostosowywane do regulacji unijnych, zwłaszcza zaś do Europejskiej Karty Małych Przedsiębiorstw. Badania prowadzone w Polsce przez wielu autorów dostarczają danych ku temu, by potwierdzić tezę, że wśród drobnych przedsiębiorców decydującą rolę w kształtowaniu ich sytuacji pracy odgrywają nadal nie mechanizmy i orientacje rynkowe, ale przede wszystkim czynniki społeczno-kulturowe
Excitation of standing kink oscillations in coronal loops
In this work we review the efforts that have been done to study the
excitation of the standing fast kink body mode in coronal loops. We mainly
focus on the time-dependent problem, which is appropriate to describe flare or
CME induced kink oscillations. The analytical and numerical studies in slab and
cylindrical loop geometries are reviewed. We discuss the results from very
simple one-dimensional models to more realistic (but still simple) loop
configurations. We emphasise how the results of the initial value problem
complement the eigenmode calculations. The possible damping mechanisms of the
kink oscillations are also discussed
Predicting sexual problems in women: The relevance of sexual excitation and sexual inhibition
This is the post-print version of the article. The official published version can be obtained from the link below.Data from a non-clinical sample of 540 heterosexual women were used to examine the relationships between scores on the Sexual Excitation/Sexual Inhibition Inventory for Women (SESII-W) and ratings of current sexual problems, lifetime arousal difficulty, lifetime orgasm difficulty, and lifetime problems with low sexual interest. Multiple regression analyses also included several demographic/background variables as predictors: age, full-time employment, completed college, children in household, married, health ratings, importance of sex, and whether the woman was in a sexual relationship. The strongest statistical predictors of both current and lifetime sexual problems were the SESII-W inhibition factors Arousal Contingency and Concerns about Sexual Function. Demographic factors did not feature largely in any of the models predicting sexual problems even when statistically significant relationships were found. If future research supports the predictive utility of the SESII-W in identifying women who are more likely to experience sexual difficulties, these scales may be used as prognostic factors in treatment studies.This study was funded, in part, by a grant from the Lilly Centre for Women's Health
Magnonic crystals — prospective structures for shaping spin waves in nanoscale
We have investigated theoretically band structure of spin waves in magnonic crystals with periodicity in one(1D),
two- (2D) and three-dimensions (3D). We have solved Landau–Lifshitz equation with the use of plane
wave method, finite element method in frequency domain and micromagnetic simulations in time domain to find
the dynamics of spin waves and spectrum of their eigenmodes. The spin wave spectra were calculated in linear
approximation. In this paper we show usefulness of these methods in calculations of various types of spin waves.
We demonstrate the surface character of the Damon–Eshbach spin wave in 1D magnonic crystals and change of
its surface localization with the band number and wavenumber in the first Brillouin zone. The surface property
of the spin wave excitation is further exploited by covering plate of the magnonic crystal with conductor. The
band structure in 2D magnonic crystals is complex due to additional spatial inhomogeneity introduced by the
demagnetizing field. This modifies spin wave dispersion, makes the band structure of magnonic crystals strongly
dependent on shape of the inclusions and type of the lattice. The inhomogeneity of the internal magnetic field
becomes unimportant for magnonic crystals with small lattice constant, where exchange interactions dominate.
For 3D magnonic crystals, characterized by small lattice constant, wide magnonic band gap is found. We show
that the spatial distribution of different materials in magnonic crystals can be explored for tailored effective
damping of spin wave
Light-induced formation of dimeric LHCII
It emerges from numerous experiments that LHCII, the major photosynthetic antenna complex of plants, can appear not only in the trimeric or monomeric states but also as a dimer. We address the problem whether the dimeric form of the complex is just a simple intermediate element of the trimer–monomer transformation or if it can also be a physiologically relevant molecular organization form? Dimers of LHCII were analyzed with application of native electrophoresis, time-resolved fluorescence spectroscopy, and fluorescence correlation spectroscopy. The results reveal the appearance of two types of LHCII dimers: one formed by the dissociation of one monomer from the trimeric structure and the other formed by association of monomers into a distinctively different molecular organizational form, characterized by a high rate of chlorophyll excitation quenching. The hypothetical structure of such an energy quencher is proposed. The high light-induced LHCII dimerization is discussed as a potential element of the photoprotective response in plants
Numerical Simulations of Magnetoacoustic-Gravity Waves in the Solar Atmosphere
We investigate the excitation of magnetoacoustic-gravity waves generated from
localized pulses in the gas pressure as well as in vertical component of
velocity. These pulses are initially launched at the top of the solar
photosphere that is permeated by a weak magnetic field. We investigate three
different configurations of the background magnetic field lines: horizontal,
vertical and oblique to the gravitational force. We numerically model
magnetoacoustic-gravity waves by implementing a realistic (VAL-C) model of
solar temperature. We solve two-dimensional ideal magnetohydrodynamic equations
numerically with the use of the FLASH code to simulate the dynamics of the
lower solar atmosphere. The initial pulses result in shocks at higher
altitudes. Our numerical simulations reveal that a small-amplitude initial
pulse can produce magnetoacoustic-gravity waves, which are later reflected from
the transition region due to the large temperature gradient. The atmospheric
cavities in the lower solar atmosphere are found to be the ideal places that
may act as a resonator for various oscillations, including their trapping and
leakage into the higher atmosphere. Our numerical simulations successfully
model the excitation of such wave modes, their reflection and trapping, as well
as the associated plasma dynamics
The effect of flows on transverse oscillations of coronal loops
In this paper we study kink oscillations of coronal loops in the presence of flows. Using the thin-tube approximation we derive the general governing equation for kink oscillations of a loop with the density varying along the loop in the presence of flows. This equation remains valid even when the density and flow are time dependent. The derived equation is then used to study the effect of flows on eigenfrequencies of kink oscillations of coronal loops. The implication of the obtained results on coronal seismology is discussed
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