Az alagút bejárata és a hazai agrárstratégia kritikus kérdései

Megállapítható, hogy a tanácskozáson résztvevÅ‘k véleménye a fundamentális kérdésekben közel esik egymáshoz, bár vannak még különbségek, fÅ‘leg a javasolt megoldásokban. Ez – az elmúlt két évtizedet figyelembe véve – mindenképpen haladásnak tekinthetÅ‘. Elmondható, hogy a komoly gondok és problémák összefogásra serkentik a közösségeket. Mindenki érzi, hogy a jelentÅ‘s agrártradíciókkal rendelke¬zÅ‘ hazai élelmiszer-gazdaság a jelenlegi pályán maradva alapanyag-termelÅ‘ agrár¬bérmunkás országgá válhat, elvesztve versenyképességének maradékát is, teljesen kiszolgáltatva, míg az ágazat jövedelemtermelése – jó esetben is – csak a túlélésre elegendÅ‘. Elmondható, hogy még nem látható a „fény az alagút végénâ€, de már formá¬lódik, hogy hol is van az az alagút, amin végig kellene haladni. Avita, illetve a mosta-nában napvilágot látott elemzések megmutatták az alagút bejáratát, az MTAAgrár¬tudományok Osztályának szervezésében létrejövÅ‘ stratégiának kellene megmutatni azt, hogy hogyan lehet ezen az alagúton a legkevesebb veszteséggel, a legnagyobb nyereséggel, a leggyorsabban átjutni úgy, hogy a hozott döntések eredményeként egy olyan magyarországi mezÅ‘- és élelmiszer-gazdaság jöjjön létre, amilyet a rendszer¬változás után megálmodtak. ----------------------------------------- It was found that the views of the participants attending the discussion were similar about fundamental issues, although there are still differences, especially with respect to the proposed solutions. Considering the last two decades, this can be seen as progress. Serious problems and troubles stimulate cooperation within the communities. Everyone feels that if we stay on the current track, Hungarian food economy, with its long traditions in agriculture, can be reduced to a mere producer of raw materials, losing even the vestiges of its competitive edge. It would become extremely vulnerable and the revenues of the sector would only be sufficient for survival, at best. We cannot yet see the light at the end of the tunnel, but the entrance of said tunnel is becoming visible. The debate and the recently published analyses outlined the entrance of the tunnel. The strategy to be arranged by the Agricultural Sciences Department of the Hungarian Academy of Sciences should show how we could cross this tunnel in the fastest manner, with the least loss and greatest gain, so that the decisions made now lead to the emergence of an agriculture and food economy which was dreamt after the change of the political system in Hungary.stratégia, agrár- és élelmiszer-gazdaság, termelÅ‘k, döntéshozók, strategy, agricultural and food economy, producers, decision-makers, Agricultural and Food Policy,

Erdőgazdálkodási javaslatok a nagygombák funkcionális és faji sokféleségének megőrzésére = Conservation of macrofungal biodiversity in managed forests - recommendations for management

Az alábbi tanulmány az erdei nagygombaközösségek sokféleségét befolyásoló erdőgazdálkodási gyakorlatok hatásait foglalja össze. A nagygombák erdőgazdálkodási szempontból fontos funkcionális csoportjainak (a fán élők, a mikorrhizaképzők és az avarbontók) ismertetése után számba vesszük azok erdei életközösségekben betöltött ökológiai szerepeit. Külön részletezve a hazai nagygombaközösségek számára előnyös és hátrányos következményeiket, kitérünk a hagyományos (vágásos) erdőgazdálkodási gyakorlat során előnyben részesített fafajok, faállomány-szerkezetek, a hátrahagyott holtfakészlet, a kitermelt faanyag közelítési, előkészítési és mozgatási módjainak, illetve az erdészeti beavatkozások időpontjainak, valamint térbeli és időbeli kiterjedtségének hatásaira. Olyan alternatív, a gombaközösségek és a különböző, hagyományos erdőgazdálkodási üzemmódok szempontjából egyaránt felvázolt gazdálkodási lehetőségeket is bemutatunk, amik a természetes bolygatási rendszert tükrözik, de a gyakorlatban is könnyen kivitelezhetők, és elősegítik az erdei nagygombaközösségek sokféleségének hatékony, tartamos védelmét. | In this chapter, the effects of forest management practices on macrofungal biodiversity are discussed. The fundamental role of wood-inhabiting, mycorrhizal and terricolous saprotrophic macrofungi in forest ecosystems and the mechanisms by which they function are reviewed; macrofungal guilds with considerable importance for forest management are listed. The positive and negative effects of the traditional (mainly shelterwood) Hungarian silviculture practices to macrofungal biodiversity are detailed separately. Special considerations were taken as for the effects of the preferred tree taxa, stand structure, dead wood properties, logging, skidding and log preparation characteristics, as well as the spatio-temporal severity and timing of management practices. In both the macrofungal and the silvicultural points of view, alternative forest management practices that are achievable in practice, but mimic the natural disturbance regime are listed to promote a sustainable conservation for macrofungal biodiversity

Runaway Positrons in Fusion Plasmas

Runaway positrons can be produced in the presence of runaway electron avalanches in magnetized plasmas. In this Letter, we determine the positron distribution, the fraction of runaway positrons, and the parametric dependences of their synchrotron radiation spectrum. We show that the maximum production occurs around γe≃30, where γe is the Lorentz factor of the fast electrons. For an avalanching positron distribution typical of tokamak plasmas, the maximum of the synchrotron radiation spectrum should be around a micron. The radiated power and spectrum shape are sensitive to the plasma parameters. Apart from its intrinsic interest, detection of radiation from positrons could be a diagnostic tool to understand the properties of the medium they propagate through

Predicting Concentration Fluctuations of Locally Emitted Air Pollutants in Urban-like Geometry Using Deep Learning

The accurate quantification of concentration fluctuations is crucial when evaluating the exposure to toxic, infectious, reactive, flammable, or explosive substances, as well as for the estimation of odor nuisance. However, in the field of Computational Fluid Dynamics (CFD), the industry currently relies predominantly on steady-state RANS turbulence models for simulating near-field pollutant dispersion, which are only capable of producing the time-averaged concentration field. This paper presents a regression relationship for calculating the standard deviation of the local concentration based on the mean concentration and the downstream distance from a point source, over a city-like surface, in the case of the wind direction perpendicular to the streets. The desired peak values and other statistical characteristics can be predicted by assuming a gamma distribution which is fitted based on the average and standard deviation. To obtain the regression function, a deep neural network model was used. The model was trained using time-resolved concentration data obtained from wind tunnel experiments. The validation results show that the concentration fluctuations predicted by the DNN-based model are in satisfactory agreement with the measurement data in terms of the skewness, the kurtosis, the median, and the peak concentrations. Furthermore, the present paper suggests a workflow for estimating the concentration fluctuations based on RANS CFD results, as well as recommendations for generating further training data for specific applications

Energetic electron transport in the presence of magnetic perturbations in magnetically confined plasmas

The transport of energetic electrons is sensitive to magnetic perturbations. By using 3D numerical simulation of test particle drift orbits we show that the transport of untrapped electrons through an open region with magnetic perturbations cannot be described by a diffusive process. Based on our test particle simulations, we propose a model that leads to an exponential loss of particles.Comment: Accepted for publication in Journal of Plasma Physics (Energetic Electrons special issue

Multiplicity Dependence in the Non-Extensive Hadronization Model Calculated by the HIJING++ Framework

The non-extensive statistical description of the identified final state particles measured in high energy collisions is well-known by its wide range of applicability. However, there are many open questions that need to be answered, including but not limited to, the question of the observed mass scaling of massive hadrons or the size and multiplicity dependence of the model parameters. This latter is especially relevant, since currently the amount of available experimental data with high multiplicity at small systems is very limited. This contribution has two main goals: On the one hand we provide a status report of the ongoing tuning of the soon-to-be-released HIJING++ Monte Carlo event generator. On the other hand, the role of multiplicity dependence of the parameters in the non-extensive hadronization model is investigated with HIJING++ calculations. We present cross-check comparisons of HIJING++ with existing experimental data to verify its validity in our range of interest as well as calculations at high-multiplicity regions where we have insufficient experimental data.Comment: This paper is based on the talk at the 18th Zim\'anyi School, Budapest, Hungary, 3-7 December 201

Differences in high p_t meson production between CERN SPS and RHIC heavy ion collisions

In this talk we present a perturbative QCD improved parton model calculation for light meson production in high energy heavy ion collisions. In order to describe the experimental data properly, one needs to augment the standard pQCD model by the transverse momentum distribution of partons ("intrinsic k_T"). Proton-nucleus data indicate the presence of nuclear shadowing and multiscattering effects. Further corrections are needed in nucleus-nucleus collisions to explain the observed reduction of the cross section. We introduce the idea of proton dissociation and compare our calculations with the SPS and RHIC experimental data.Comment: Talk presented by G. Papp at Zakopane 2001 School, Zakopane, 2001 June; 10 pages with 3 EPS figure