44 research outputs found
Functional richness outperforms taxonomic richness in predicting ecosystem functioning in natural phytoplankton communities
A Malom-Tisza holtág nyári rétegződési stabilitása és oxigénviszonyai 2007-2010-ben = Characteristics of the summer thermal stratification and the oxygen profile in the Malom-Tisza oxbow (2007-2010)
A Malom-Tisza holtág nyári vízoszlop stabilitását vizsgáltuk a termikus és oxigén viszonyok tükrében (2007-2010), különös hangsúlyt fektetve az epilimnion és hipolimnion évek közötti különbségeire. Vizsgálatainkkal igazoltuk, hogy a holtág stabilan rétegződik minden évben (dimiktikus). A holtág a 4 év során minden nyáron rendkívül stabilan rétegződött (RWCSmax = 479), mely minden esetben anoxikus hipolimnionnal párosult. A nyári rétegződés kialakulásában jelentős szerepe volt a (i) fetchhossznak, (ii) tavaszi időjárási körülményeknek, melyek meghatározzák a termoklin induló mélységét és a hipolimnion hőmérsékletét, (iii) a nyári időjárási körülményeknek, melyek befolyásolják az epilimnion évszakos, és napszakos hőmérséklet viszonyait. Ezen évek közötti különbségek tükröződhetnek rétegződő állóvizeink vízminősítésekor, mivel a vízoszlop stabilitás változása nagyban meghatározza a fitoplankton fajösszetételét, és azon keresztül annak minősítését
Az édesvízi medúza (Craspedacusta sowerbii Lankaster, 1880) magyarországi előfordulása | The freshwater jellyfish (Craspedacusta sowerbii Lankester, 1880) in Hungarian waters
An invasive hydromedusa species, the Craspedacusta sowerbii was found in three Hungarian
lakes. The individuals were seen in low density near the shore in two of the lakes and in the pelagical
region in the third one. As the species shows widespread distribution and it is also common in Europe,
this record was expected. In this article some features upon C. sowerbii occurrences are given with
mentioning of some unconfirmed records. Monitoring of Hungarian waters for C. sowerbii for the polip
form is suggested since the reasons of the alteration to meduse form is not well studied; furthermore
the polip form’s occurrence may be less variable
Functional diversity of phytoplankton highlights long-term gradual regime shift in the middle section of the Danube River due to global warming, human impacts and oligotrophication
Trait-based paradise – or only feeding the computer with biology?
We briefly discuss the relationship between the biological knowledge and the methodological issues related to traitbased ecological analyses. We provide illustrative examples and argue that the biological novelty of trait-based research is generally less than expected - while new information is mostly coming from data management and methodology
Bit-Table Based Biclustering and Frequent Closed Itemset Mining in High-Dimensional Binary Data
During the last decade various algorithms have been developed and proposed for discovering overlapping clusters in high-dimensional data. The two most prominent application fields in this research, proposed independently, are frequent itemset mining (developed for market basket data) and biclustering (applied to gene expression data analysis). The common limitation of both methodologies is the limited applicability for very large binary data sets. In this paper we propose a novel and efficient method to find both frequent closed itemsets and biclusters in high-dimensional binary data. The method is based on simple but very powerful matrix and vector multiplication approaches that ensure that all patterns can be discovered in a fast manner. The proposed algorithm has been implemented in the commonly used MATLAB environment and freely available for researchers