PAC bounds of continuous Linear Parameter-Varying systems related to neural ODEs

We consider the problem of learning Neural Ordinary Differential Equations (neural ODEs) within the context of Linear Parameter-Varying (LPV) systems in continuous-time. LPV systems contain bilinear systems which are known to be universal approximators for non-linear systems. Moreover, a large class of neural ODEs can be embedded into LPV systems. As our main contribution we provide Probably Approximately Correct (PAC) bounds under stability for LPV systems related to neural ODEs. The resulting bounds have the advantage that they do not depend on the integration interval.Comment: 12 page

Gradient representations in ReLU networks as similarity functions

Feed-forward networks can be interpreted as mappings with linear decision surfaces at the level of the last layer. We investigate how the tangent space of the network can be exploited to refine the decision in case of ReLU (Rectified Linear Unit) activations. We show that a simple Riemannian metric parametrized on the parameters of the network forms a similarity function at least as good as the original network and we suggest a sparse metric to increase the similarity gap.Comment: Accepted at 29th ESANN 2021, 6-8 October 2021, Belgium, 7 pages, 1 figur

Alkalmazkodási stratégiák a vidék gazdaságában = Adaptational strategies in rural economy

A hároméves, különböző jellegű vidéki települések alkalmazkodási stratégiáinak feltérképezésére irányuló kutatásunk négy megyében zajlott: dolgoztunk munkanélküliség által erősen sújtott, perifériális helyzetben lévő mezőgazdasági-, valamint volt-ipari térségben, továbbá nagyvárosok vonzáskörzetében jobb helyzetben levő mezőgazdasági és vállalkozó faluban is. Négy településen (Szatmárcseke, Borsodnádasd, Derecske és Tarján) mélyfúrás jellegű kutatás zajlott; nagyszámban készültek interjúk, Borsodnádasdon és Szatmárcsekén egyetemi diákok segítségével kérdőíves felmérés is zajlott. Mikrotérségi szintű vizsgálat folyt Derecske környékén (5 település) és a szatmári Tiszaháton (13 település). Az OTKA kutatás keretében összesen 858 kérdőív, 180 db. interjú készült, ami mellett térségi és helyi statisztikákat, és egyéb forrásokat is gyűjtöttünk. Emellett az Alapítvány 2007-ben Kétvölgyön a résztvevőkutatók számára műhelyvitát rendezett, majd a Magyar Művelődési Intézettel közösen decemberben konferenciát szervezett "Fiatal kutatók Márkus István nyomdokain: falukutatók Borsodnádasdon" címmel, amin a kutatók mellett a Debreceni Egyetem és az ELTE is képviseltették magát. A három év alatt az öt kutató 22 konferencia előadást tartott a témában, 8 tanulmányt publikált, további 4 a jelenleg Borsodnádasdról készülő kötetben jelenik meg 2008-ban. A résztvevő kutatók mindegyike doktorjelölt, és dolgozatához felhasználja az OTKA kutatás eredményeit. | The three years long research was executed in four counties: we have worked in peripheral agricultural and collapsed industrial villages, which were distressed very much by unemployment. Besides we have done research also in agricultural and 'entrepreneur' areas near to bigger cities, which are in better situation. There were deep research and many interviews were made in four settlements (Szatmárcseke, Borsodnádasd, Derecske, Tarján); in Borsodnádasd and Szatmárcseke there were quantitative surveys too which were carried out with university students. In five settlements (around Derecske) and in the Szatmár Tiszahát (10 villages) there were micro-regional researches. During the OTKA project we have made 858 questionnaires and 210 interviews, besides regional and local statistics and other information were collected. In 2007 the Foundation organized a workshop for the participant researchers in Kétvölgy and in December with the Hungarian Culture Institute organized a conference with the title of "Young researchers in the wake of Márkus István: researchers in Borsodnádasd" when out of the researchers the Debrecen University and ELTE were also represented themselves. During the three years the five participant researchers had 22 presentations on the subject, 8 studies were published and 4 are under edition in a book of Borsodnádasd. Being the participant researchers Ph.D candidates, writing their thesis they will use the OTKA results

Reversal of Multidrug Resistance by Symmetrical Selenoesters in Colon Adenocarcinoma Cells

Recently, selenium containing derivatives have attracted more attention in medicinal chemistry. In the present work, the anticancer activity of symmetrical selenoesters was investigated by studying the reversal of efflux pump-related and apoptosis resistance in sensitive and resistant human colon adenocarcinoma cells expressing the ABCB1 protein. The combined effect of the compounds with doxorubicin was demonstrated with a checkerboard assay. The ABCB1 inhibitory and the apoptosis-inducing effects of the derivatives were measured with flow cytometry. Whole transcriptome sequencing was carried out on Illumina platform upon the treatment of resistant cells with the most potent derivatives. One ketone and three methyl ester selenoesters showed synergistic or weak synergistic interaction with doxorubicin, respectively. Ketone selenoesters were the most potent ABCB1 inhibitors and apoptosis inducers. Nitrile selenoesters could induce moderate early and late apoptotic processes that could be explained by their ABCB1 modulating properties. The transcriptome analysis revealed that symmetrical selenoesters may influence the redox state of the cells and interfere with metastasis formation. It can be assumed that these symmetrical selenocompounds possess toxic, DNA-damaging effects due to the presence of two selenium atoms in the molecule, which may be augmented by the presence of symmetrical groups

Population dynamics and genetic changes of Picea abies in the South Carpathians revealed by pollen and ancient DNA analyses

Background: Studies on allele length polymorphism designate several glacial refugia for Norway spruce (Picea abies) in the South Carpathian Mountains, but infer only limited expansion from these refugia after the last glaciation. To better understand the genetic dynamics of a South Carpathian spruce lineage, we compared ancient DNA from 10,700 and 11,000-year-old spruce pollen and macrofossils retrieved from Holocene lake sediment in the Retezat Mountains with DNA extracted from extant material from the same site. We used eight primer pairs that amplified short and variable regions of the spruce cpDNA. In addition, from the same lake sediment we obtained a 15,000-years-long pollen accumulation rate (PAR) record for spruce that helped us to infer changes in population size at this site. Results: We obtained successful amplifications for Norway spruce from 17 out of 462 pollen grains tested, while the macrofossil material provided 22 DNA sequences. Two fossil sequences were found to be unique to the ancient material. Population genetic statistics showed higher genetic diversity in the ancient individuals compared to the extant ones. Similarly, statistically significant Ks and Kst values showed a considerable level of differentiation between extant and ancient populations at the same loci. Lateglacial and Holocene PAR values suggested that population size of the ancient population was small, in the range of 1/10 or 1/5 of the extant population. PAR analysis also detected two periods of rapid population growths (from ca. 11,100 and 3900 calibrated years before present (cal yr BP)) and three bottlenecks (around 9180, 7200 and 2200 cal yr BP), likely triggered by climatic change and human impact. Conclusion: Our results suggest that the paternal lineages observed today in the Retezat Mountains persisted at this site at least since the early Holocene. Combination of the results from the genetic and the PAR analyses furthermore suggests that the higher level of genetic variation found in the ancient populations and the loss of ancient allele types detected in the extant individuals were likely due to the repeated bottlenecks during the Holocene. This study demonstrates how past population size changes inferred from PAR records can be efficiently used in combination with ancient DNA studies. The joint application of palaeoecological and population genetic analyses proved to be a powerful tool to understand the influence of past population demographic changes on the haplotype diversity and genetic composition of forest tree species

Az UV-B sugárzás hatása a kukorica fejlődésére = Effect of UV-B radiation on maize development

Az ózonréteg évtizedek óta tartó vékonyodása az UV-B sugárzás globális szinten történő megemelkedéséhez vezetett. Nemesítési programunkban ezért célul tűztük ki olyan beltenyésztett vonalak és hibridek nemesítését, melyek e negatív környezeti hatást jobban tolerálni tudják. Ugyanazon 10 eltérő tenyészidejű és különböző genetikai háttérbázissal rendelkező beltenyésztett vonalakat vizsgálva megállapítottuk, hogy a magasabb sugárzási szint a a kukorica leveleiben szignifikánsan magasabb össz-antocián termelést eredményezett. Mérési eredményeink igazolták, hogy vannak olyan anyagok, melyek antociántartalma eleve magas, így ezért a nagyobb UV-B sugárzásra kevésbé reagálnak, míg más típusok szignifikánsan magasabb össz-antocián termelésel reagálnak. A martonvásári levélmintáknál kipróbálásra került egy új, fluoreszcencia leképezési technikán alapuló módszer. Ennek segitségével a különböző stresszorok által okozott funkciócsökkenés képszerűen is megjelenithető. A speciális fitotron kamrában mértük a magasabb UV-B sugárzás fotoszintézisre gyakorolt hatását. Az itt kapott eredmények is igazolták egyes korai genotípusok érzékenységét, ami a netto fotoszintetikus aktivitásuk csökkenésében jelentkezett. Az antioxidáns enzimek aktivitásával kapcsolatos eredményeink is azt a megfigyelést támasztják alá, hogy ezek a korai, az UV-B sugárzásra érzékeny beltenyésztett vonalaknak a reaktív oxigénformákat elimináló képessége gyengébb, mint a későieké. | The ozone layer has become thinner in recent decades, leading to an increase in UV-B radiation on a global scale. One aim of our breeding programme is thus to develop inbred lines and hybrids capable of tolerating this negative environmental effect. Tests on ten inbred lines with diverse vegetation periods and genetic backgrounds revealed that a higher radiation level led to the production of a significantly higher quantity of total anthocyanin in maize leaves. The measurements proved that the initial anthocyanin content was higher in some genotypes, which thus had a milder response to higher UV-B radiation levels, while other types responded with a significant increase in total anthocyanin production. A new method based on the fluorescence imaging technique was tested on leaf samples taken in Martonvásár. This method allows the reduction in functioning ability caused by various stressors to be recorded before the damage is measurable by other means. The special phytotron chamber was used to determine the effect of higher UV-B radiation levels on photosynthesis. These measurements confirmed the sensitivity of certain early genotypes, revealed by a reduction in net photosynthetic activity. Measurements on the activity of antioxidant enzymes confirmed that early inbred lines sensitive to UV-B radiation were less able to eliminate reactive oxygen species than later genotypes

Iron(II)-cyclopentadienyl compounds are cytotoxic against colon adenocarcinoma cell lines: Ethylenebis(diphenylphosphane) vs. triphenylphosphane

Structure-activity studies aiming to understand the role of each coligand in the formulation of new metallodrugs is an important subject. In that frame, six new compounds with general formula [Fe(η5-C5H5)(dppe)(L)][CF3SO3] with L = benzonitriles (1–4) or carbon monoxide (5) and compound [Fe(η5 -C5H5)(CO)(PPh3)2][CF3SO3] (6) were synthesized and compared with three other previously reported compounds [Fe(η5-C5H5)(CO)(L)(PPh3)][CF3SO3]. We were particularly interested in assessing the effect of dppe vs. (PPh3 + CO) for this set of compounds. For that, all compounds were tested against two human colon adenocarcinoma cell lines, Colo205 and the refractile Colo320 (expressing ABCB1, an efflux pump causing multidrug resistance), showing IC50 values in the micromolar range. The presence of dppe in the compound’s coordination sphere over (PPh3 + CO) allows for more redox stable compounds showing higher cytotoxicity and selectivity, with improved cytotoxicity towards resistant cells that is not related to the inhibition of ABCB1. Further studies with GSH and H2O2 for selected compounds indicated that their antioxidant ability is not probably the main responsible for their cytotoxicity