721 research outputs found
Agroforestry research and development in Hungary
PosterHungary is a traditionally agricultural country, therefore the „old” agroforestry technologies (windbreaks, shelter-belts, hedgerows, wooded pastures) had been applied in large scale in the past centuries. From the early nineties the positive trend of increasing area of protective forest belts first stopped, then reversed. The former area of forest belts (35 000 hectares) has decreased by 50% up to this time. The high ratio of “risky” territories demonstrates the strong need for the development of rural areas, by eg. the implementation of innovative agricultural technology able to increase social-economic sustainability.
Followed from the forest belt research project started in the ’60s and ran over the course of several decades, a new line of experiments has started some years ago in the UWH Faculty of Forestry with the aim to develop a modell for the design and construction of forest belts by the combination of digital modelling and field sampling with analytical methods. The examination and development of windbreaks and shelter belt system will be continued within the frame of a national project focused on climate – vegetation relationship.
In 2012 the UWH Cooperational Research Centre, together with local cooperatives and farmers have set the objective of integrating modern agroforestry technologies in their on-farm agricultural activity and establishing new experimental sites available for future research and demonstration purposes. This cooperation will also contribute to the „AGFORWARD” international research project on agroforestry.
In the Corvinus University of Budapest, Department of Ecological Farming and Sustainable Production Systems an R&D project on forest gardens started in 2010.
From this year agroforestry appears among the “determinative research and development subjects” of the Ministry of Rural Development. This development and the increasing number of research projects show agroforestry rising again in Hungary
Magnetization and susceptibility of ferrofluids
A second-order Taylor series expansion of the free energy functional provides
analytical expressions for the magnetic field dependence of the free energy and
of the magnetization of ferrofluids, here modelled by dipolar Yukawa
interaction potentials. The corresponding hard core dipolar Yukawa reference
fluid is studied within the framework of the mean spherical approximation. Our
findings for the magnetic and phase equilibrium properties are in quantitative
agreement with previously published and new Monte Carlo simulation data.Comment: 8 pages including 4 figure
Comparison of soil erosion dynamics under extensive and intensive cultivation based on basic soil parameters
The conservation of soil and its elemental feature, t
he soil fertility has not just national and
agricultural business interest, since the fertile soil is
an elemental part of the material turnover in the
environment. The soil erosion can reach huge spatial e
xtensions and starts with the most valuable part: the
upper, fertile layer. So, its research is crucial for
our future survival. Our studied area can be found
in
Gerézdpuszta at the Koppány
-valley of Hungary, which is a sensitive erosion area.
We sampled the upper 30
cm of soil layer in every 10 meters that resulted 32-32
point samples on the arable and on the grassland,
respectively. One sample was taken under the forest as r
eference. We analyzed the basic soil parameters:
CaCO
3
, pH, AL-P
2
O
5
, AL-K
2
O, Kuron’s higroscopicity, SOM and the particle size di
stribution was
determined. Besides, we examined the connection between
the given results from laboratory soil analyses and
the Munsell-type and Google Earth satellite image colors. O
ur results show the erosion dynamic on our
sample slope, and the main differences in basic soil paramet
ers between different intensities. The main
indicator of soil erosion dynamic were the CaCO
3
, the SOM, AL-P
2
O
5
and the particle size distribution,
where the SOM and CaCO
3
were correlate with the Munsell and Google Earth col
or also
The contact binary VW Cephei revisited: surface activity and period variation
Context. Despite the fact that VW Cephei is one of the well-studied contact
binaries in the literature, there is no fully consistent model available that
can explain every observed property of this system.
Aims. Our motivation is to obtain new spectra along with photometric
measurements, to analyze what kind of changes may have happened in the system
in the past two decades, and to propose new ideas for explaining them.
Methods. For the period analysis we determined 10 new times of minima from
our light curves, and constructed a new OC diagram of the system. Radial
velocities of the components were determined using the cross-correlation
technique. The light curves and radial velocities were modelled simultaneously
with the PHOEBE code. All observed spectra were compared to synthetic spectra
and equivalent widths of the H line were measured on their differences.
Results. We have re-determined the physical parameters of the system
according to our new light curve and spectral models. We confirm that the
primary component is more active than the secondary, and there is a correlation
between spottedness and the chromospheric activity. We propose that flip-flop
phenomenon occurring on the primary component could be a possible explanation
of the observed nature of the activity. To explain the period variation of VW
Cep, we test two previously suggested scenarios: presence of a fourth body in
the system, and the Applegate-mechanism caused by periodic magnetic activity.
We conclude that although none of these mechanisms can be ruled out entirely,
the available data suggest that mass transfer with a slowly decreasing rate
gives the most likely explanation for the period variation of VW Cep.Comment: 13 pages, 18 figures, 9 tables, accepted for publication in Astronomy
and Astrophysic
Phase transitions and ordering of confined dipolar fluids
We apply a modified mean-field density functional theory to determine the
phase behavior of Stockmayer fluids in slitlike pores formed by two walls with
identical substrate potentials. Based on the Carnahan-Starling equation of
state, a fundamental-measure theory is employed to incorporate the effects of
short-ranged hard sphere - like correlations while the long-ranged
contributions to the fluid interaction potential are treated perturbatively.
The liquid-vapor, ferromagnetic liquid - vapor, and ferromagnetic liquid -
isotropic liquid first-order phase separations are investigated. The local
orientational structure of the anisotropic and inhomogeneous ferromagnetic
liquid phase is also studied. We discuss how the phase diagrams are shifted and
distorted upon varying the pore width.Comment: 15 pages including 8 figure
Substructurability:The effect of interface location on a real-time dynamic substructuring test
A full-scale experimental test for large and complex structures is not always achievable. This can be due to many reasons, the most prominent one being the size limitations of the test. Real-time dynamic substructuring is a hybrid testing method where part of the system is modelled numerically and the rest of the system is kept as the physical test specimen. The numerical–physical parts are connected via actuators and sensors and the interface is controlled by advanced algorithms to ensure that the tested structure replicates the emulated system with sufficient accuracy. The main challenge in such a test is to overcome the dynamic effects of the actuator and associated controller, that inevitably introduce delay into the substructured system which, in turn, can destabilize the experiment. To date, most research concentrates on developing control strategies for stable recreation of the full system when the interface location is given a priori. Therefore, substructurability is mostly studied in terms of control. Here, we consider the interface location as a parameter and study its effect on the stability of the system in the presence of delay due to actuator dynamics and define substructurability as the system’s tolerance to delay in terms of the different interface locations. It is shown that the interface location has a major effect on the tolerable delays in an experiment and, therefore, careful selection of it is necessary
Activity of 50 Long-Period Comets Beyond 5.2 AU
Remote investigations of the ancient solar system matter has been
traditionally carried out through the observations of long-period (LP) comets
that are less affected by solar irradiation than the short-period counterparts
orbiting much closer to the Sun. Here we summarize the results of our
decade-long survey of the distant activity of LP comets. We found that the most
important separation in the dataset is based on the dynamical nature of the
objects. Dynamically new comets are characterized by a higher level of activity
on average: the most active new comets in our sample can be characterized by
afrho values >3--4 higher than that of our most active returning comets. New
comets develop more symmetric comae, suggesting a generally isotropic outflow.
Contrary to this, the coma of recurrent comets can be less symmetrical,
ocassionally exhibiting negative slope parameters, suggesting sudden variations
in matter production. The morphological appearance of the observed comets is
rather diverse. A surprisingly large fraction of the comets have long, teniouos
tails, but the presence of impressive tails does not show a clear correlation
with the brightness of the comets.Comment: 21 pages, 4 figures, accepted for publication in A
Peromyscus as a Mammalian Epigenetic Model
Deer mice (Peromyscus) offer an opportunity for studying the effects of natural genetic/epigenetic variation with several advantages over other mammalian models. These advantages include the ability to study natural genetic variation and behaviors not present in other models. Moreover, their life histories in diverse habitats are well studied. Peromyscus resources include genome sequencing in progress, a nascent genetic map, and >90,000 ESTs. Here we review epigenetic studies and relevant areas of research involving Peromyscus models. These include differences in epigenetic control between species and substance effects on behavior. We also present new data on the epigenetic effects of diet on coat-color using a Peromyscus model of agouti overexpression. We suggest that in terms of tying natural genetic variants with environmental effects in producing specific epigenetic effects, Peromyscus models have a great potential
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