2,201 research outputs found
Uniqueness of the electrostatic solution in Schwarzschild space
In this Brief Report we give the proof that the solution of any static test
charge distribution in Schwarzschild space is unique. In order to give the
proof we derive the first Green's identity written with p-forms on (pseudo)
Riemannian manifolds. Moreover, the proof of uniqueness can be shown for either
any purely electric or purely magnetic field configuration. The spacetime
geometry is not crucial for the proof.Comment: 3 pages, no figures, uses revtex4 style file
Pathological and histopatnotogical studies of the swimbladder of eels Anguilla anguitla infected by Angutlticpta crassus (Nemafoda: Dracuncuioidea)
The swimbladder lesions produced by Anguillicola crassus (Nematoda) infection, causing mass mortality among eels in Lake Balaton (Hungary) were studied by histological methods. In the initial phase of infection, no severe changes developed in the swimbladder wall despite the presence and intensive blood-sucking activity of worms that filled the lumen of the swimbladder. After disruption of the worms and primarily because of repeated reinfection by larvae, however, the wall of the swimblaader markedly thickened and showed degenerative, inflammatory and proliferative changes. Acute processes were characterized by epithelial hyperplasia and hyperaemia of the swimbladder wall. In cases of chronic swimbladder inflammation, oedema and hyperplasia of tissues of the tunica propria, submucosa and serosa could be observed, as well as granulomatoid infiltration by mononuclear cells and fibrinoid degeneration around the larvae
Selection of winter cereals for organic agriculture
Productivity in agriculture has more than tripled in developed countries since the 1950s. Beyond the success of plant breeding, the increased use of inorganic fertilizers, application of pesticides, and spread of irrigation also contributed to this success. However, impressive yield increases started to decline in the 1980s because of the lack of sustainability.
One of the most beneficial ways to increase sustainability is organic agriculture. In such systems the prerequisite of successful farming is the availability of crop genotypes that perform well. However, selection of winter cereals for sub-optimal growing conditions is still neglected, and the organic seed market also lacks of information on credibly tested varieties suitable for organic agriculture
Delineation of the Pannonian vegetation region
Phytogeographical regions have been set up traditionally on the basis of the flora. Several examples indicate that the potential natural vegetation is also suitable for this purpose although the flora- and vegetation-based boundaries do not necessarily overlap. We define a vegetation region as an area where the physical geographic features are rather uniform, and which consists of landscapes with floristically/structurally similar vegetation and/or their repetitive mosaics. In this paper, we delimited the boundaries of the Pannonian region based on the distribution of characteristic plant communities. The line runs most often on the border between Quercus cerris-Quercus petraea and Carpinus betulus/Fagus sylvatica dominated landscapes. We provided descriptions of the potential vegetation on both sides of the boundary. The region has an area of 167,012 km2. The region is either in direct contact with the neighboring regions (e.g., Western Carpathians), or is separated from them by transitional areas (towards the Eastern Alps), and character-poor areas with non-Pannonian, non-Alpine, non-Dinaric vegetation (in the southwest to the Western Balkan). Often, the boundary does not coincide with the boundary of the Pannonicum floristic province. We found that vegetation region boundaries can help reevaluate long-established floristic region boundaries. The boundary of the ’floristic Pannonian region’ also requires revision based on integrated distribution databases and statistical analyses. We argue that the method applied here is simple, repeatable and falsifiable. Our map provides an opportunity to the European Union to use a scientifically more sound biogeographical circumscription of the Pannonian region in her Natura 2000 and other programs
Economic necessity for developing the milk sector
The Merinos dominating in the Hungarian sheep industry and the profitability of sheep production
is not as high as would be necessary. Economic analysis was made to find out the possible break-even points.
According to the results, the increase of milk production might be the key to solve this problem, but some
conditions should be considered. Regarding the data presented the possible conclusions might be summarized
as follows: Enlarging the stock without improving the phenotypic background is not profitable. This method will
lead to a deadlock. The utilization of milk breeds under the present conditions could be realized: (i) if the costs of
changing the breeding animals could be covered from other sources, since national sources are not available;
(ii) if the attitude of the managers and employees of milk sheep farms could change; and (iii) if the price of milk
was reasonable and the state purchase prices could reach the average prices of the EU (1 Euro/litre)
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