Are Forest Fires Predictable?

Dynamic mean field theory is applied to the problem of forest fires. The starting point is the Monte Carlo simulation in a lattice of million cells. The statistics of the clusters is obtained by means of the Hoshen--Kopelman algorithm. We get the map $p_n\to p_{n+1}$, where $p_n$ is the probability of finding a tree in a cell, and $n$ is the discrete time. We demonstrate that the time evolution of $p$ is chaotic. The arguments are provided by the calculation of the bifurcation diagram and the Lyapunov exponent. The bifurcation diagram reveals several windows of stability, including periodic orbits of length three, five and seven. For smaller lattices, the results of the iteration are in qualitative agreement with the statistics of the forest fires in Canada in years 1970--2000.Comment: 13 pages, 13 figure

Before the neolithization: Causes of mesolithic diversity in the Southern Balkans

The Balkans, particularly southern and central, were sparsely populated in the Mesolithic and the occupation networks in that period were discontinous and highly diversified, contrasting with the density and homogeneity of the Early Neolithic. The aim of this paper is to describe the environmental conditions of the Mesolithic sites in relation to Early Holocene climatic fluctuations and to discuss the causes of specificity and diversity of culture and behaviour at this period. Some general trends are observable in the adaptation to Early Holocene environments (trends in faunal exploitation; for ex. shift from high ranked large game to low ranked small animals) but also particular adaptations to local conditions (technological changes due to difficulties in access to better quality lithic raw materials, adaptations to coastal or to terrestrial resources reflecting the unique features of site use, etc). The diversity of the Mesolithic is also reflected in cultural taxonomy: in some sequences continuity of the Balkan Epigravettian techno-morphological tradition can be seen as opposed, in other sequences, to highly isolated groups with technology and tool morphology adapted to local raw materials and specific activities. The Balkan Mesolithic was not completely cut-off from the Western Mediterranean techno-morphological influences (particularly in Southern Greece) and from the Anatolian lithic traditions (seen only in the Northern Aegean). A more intensive network of marine contacts is confirmed by obsidian circulation in the Aegean Basin

Linear Band Pottery Culture (LBK) lithic industry from Apc

The general inventory of the chipped stone artefacts coming from the LBK features at Apc indicates that a specific, small scale, local lithic production was conducted on-site. Majority of used raw materials are limnoquartzites (nearly 70%) originating mainly from the Mátra and Cserhát Mountains. The use of rather poor quality local raw materials influenced the technique of working raw materials, which was employed throughout the period of the functioning of LBK settlements at Apc. As a consequence, most tools were made on flakes. At the same time, as early as the oldest phase a limited supply of blade blanks and blade tools, produced elsewhere, was used. The ground stone artefacts and fragments included lower and upper grinding stones, plaquettes with polished surfaces, hammerstones, grinders/pounders. The raw materials used in the ground stone industry are either local (quartz, conglomerate, sandstone) or mesolocal (gabbro, basalt) coming from river alluvia or from the hills at the Hungarian—Slovakian border. Andesites, probably from the Mátra Mountains, occur in small quantities. Thus, the raw materials exploited at Apc demonstrate contacts with eastern region, however the site is the easternmost LBK settlement. | Az apci lelőhely VK-objektumaiból származó pattintottkő-leletek általános összetétele arra vall, hogy a telepen speciális, kis léptékű, helyi kőeszköz-előállítás folyt. Legnagyobb mennyiségben (közel 70%) limnokvarcitokat használtak fel nyersanyagként, amelyek a Mátra és a Cserhát hegységből származtak. A többnyire gyenge minőségű nyersanyagok felhasználása befolyásolta a feldolgozási technikákat is, amelyek nem változtak az apci VK-telep teljes fennállása alatt. Ennek következtében az eszközök nagyrészt szilánkon készültek. Ugyanakkor már a telep életének legkorábbi fázisától kezdve használtak egy kevés pengét és pengeeszközt is, amelyeket máshonnan szereztek be. A csiszolt eszközök és szerszámkövek között találunk alsó és felső őrlőköveket, csiszolt felületű kőlapokat, ütőköveket és mozsártörőket, valamint azok töredékeit. Az ebben az iparban felhasznált nyersanyagok vagy helyiek (kvarc, konglomerátum, homokkő), vagy regionálisak (gabbró, bazalt), amelyek folyóüledékekből vagy a magyar—szlovák határnál lévő hegyekből származhatnak. Kis mennyiségben előfordul andezit is, valószínűleg a Mátrából. Így hát az Apcon felhasznált kőnyersanyagok keleti területekkel mutatnak kapcsolatot, holott a lelőhely a nyugati VK legkeletibb települése

Delving into the reducing effects of the GABAB positive allosteric modulator, KK-92A, on alcohol-related behaviors in rats

Recent studies have demonstrated the ability of the positive allosteric modulator (PAM) of the GABAB receptor (GABAB PAM), KK-92A, to suppress operant alcohol self-administration and reinstatement of alcohol seeking in selectively bred Sardinian alcohol-preferring (sP) rats. The present study was designed to scrutinize the suppressing effects of KK-92A on alcohol-related behaviors; to this end, four separate experiments were conducted to address just as many new research questions, some of which bear translational value. Experiment 1 found that 7-day treatment with KK-92A (0, 5, 10, and 20 mg/kg, intraperitoneally [i.p.]) effectively reduced alcohol intake in male sP rats exposed to the home-cage 2-bottle "alcohol (10% v/v) vs. water" choice regimen with 1 hour/day limited access, extending to excessive alcohol drinking the ability of KK-92A to suppress operant alcohol self-administration. Experiment 2 demonstrated that the ability of KK-92A to reduce lever-responding for alcohol was maintained also after acute, intragastric treatment (0, 20, and 40 mg/kg) in female sP rats trained to lever-respond for 15% (v/v) alcohol under the fixed ratio 5 schedule of reinforcement. In Experiment 3, acutely administered KK-92A (0, 5, 10, and 20 mg/kg, i.p.) dampened alcohol-seeking behavior in female sP rats exposed to a single session under the extinction responding schedule. Experiment 4 used a taste reactivity test to demonstrate that acute treatment with KK-92A (0 and 20 mg/kg, i.p.) did not alter either hedonic or aversive reactions to a 15% (v/v) alcohol solution in male sP rats, ruling out that KK-92A-induced reduction of alcohol drinking and self-administration could be due to alterations in alcohol palatability. Together, these results enhance the behavioral pharmacological profile of KK-92A and further strengthen the notion that GABAB PAMs may represent a novel class of ligands with therapeutic potential for treating alcohol use disorder

Excavation along the easternmost frontier of the LBK in NE-Hungary at Apc-Berekalja I (2008–2009)

The topographical position and size of the site, the number of detected houses, the presence of the early phase make the Apc-Berekalja I settlement one of the most significant sites of the LBK in Hungary. The ongoing processing of the excavation data provided already some very important observations. The geoarchaeological results demonstrated the presence of the in situ soil of the Neolithic period and effects of floods on the settlement. The study of the chipped and ground stone material coming from the Neolithic features revealed no conspicuous changes in the lithic industry of the settlement from the pre-Notenkopf to Želiezovce phases of the LBK. Lithic raw materials came exclusively from territories to the east of the site, which is an evidence of the isolation of the LBK groups that inhabited Apc. | Földrajzi helyzete, a lelőhely mérete, a megfigyelt házak száma és a korai fázis megléte alapján Apc-Berekalja I. az egyik legjelentősebb magyarországi VK-település. Az ásatási adatok még folyamatban lévő feldolgozása során közlésre méltó eredmények születtek. A geoarcheológiai vizsgálatok kimutatták egy neolitikus korú talaj in situ meglétét, valamint a települést sújtó áradásokat. A neolitikus korú objektumokból származó pattintott és szerszámkövek a település fennállása alatt a kőipar lényegi változatlanságáról tanúskodnak a VK korai időszakától a zselízi fázisáig. A településen élők a kőnyersanyagokat kizárólag a keletre eső területekről szerezték be, ami az itt lakó csoport izoláltságát igazolja

Evolution and environment of the eastern linear pottery culture: A case study in the site of Polgár-Piócási-Dűlő

A salvage excavation preceding a major investment project was conducted in 2006–2007, during which associated settlement features of a Middle Neolithic, Eastern Linear Pottery Culture (Alföld Linearbandkeramik – ALBK) were uncovered in an area called Piócási-dűlő on the eastern outskirts of Polgár. The features of the ALBK settlement date from two periods. The cluster of multi-functional pits yielding a rich assortment of finds, the handful of post-holes and an unusual ritual well found in the southern part of the investigated area formed one unit from the earliest phase of the Middle Neolithic (ALBK I). The settlement’s other occupation can be assigned to the late phase of the Middle Neolithic (ALBK IV). Five houseplans representing the remains of timber-framed buildings outlined a distinct area with three multi-functional pits. Associated with the above features were 8 burials. The preliminary archaeobotanical results from Polgár–Piócási-dűlő are based on the plant material found within the sediments of 11 archaeological structures, which mainly represent pits and a welI. It can be stated that the natural environment offered habitats in which oak trees dominated in the local vegetation, forming floodplain forests and wooded steppes. They also provided food in the form of fruits and formed an optimal habitat for domestic animals. Arable fields were probably also established in the vicinity of the settlements, suggested by findings of macroscopic plant remains that represented cultivated species. In both settlement phases lithic production activities are manifested both by the local on-site lithic production and – most importantly – by the presence of imported, mainly mesolocal, raw materials that point to contacts with deposit areas, or off-site preliminary working of obsidian and limnoquartzites. The kit of harvesting tools and a large number of grinding stones – especially in the younger phase – for the preparation of plant food suggest a major role of plant cultivation

Proofreading of pre-40S ribosome maturation by a translation initiation factor and 60S subunits

In the final steps of yeast ribosome synthesis, immature translation-incompetent pre-40S particles that contain 20S pre-rRNA are converted to the mature translation-competent subunits containing the 18S rRNA. An assay for 20S pre-rRNA cleavage in purified pre-40S particles showed that cleavage by the PIN domain endonuclease Nob1 was strongly stimulated by the GTPase activity of the cytoplasmic translation initiation factor eIF5b/Fun12. Cleavage of the 20S pre-rRNA was also inhibited in vivo and in vitro by blocking binding of Fun12 to the 25S rRNA through specific methylation of its binding site. Cleavage competent pre-40S particles stably associate with Fun12 and form 80S complexes with 60S ribosomal subunits. We propose that recruitment of 60S subunits promotes GTP-hydrolysis by Fun12, leading to structural rearrangements within the pre-40S particle that bring Nob1 and the pre-rRNA cleavage site together

Genome-Scale Analysis of Translation Elongation with a Ribosome Flow Model

We describe the first large scale analysis of gene translation that is based on a model that takes into account the physical and dynamical nature of this process. The Ribosomal Flow Model (RFM) predicts fundamental features of the translation process, including translation rates, protein abundance levels, ribosomal densities and the relation between all these variables, better than alternative (‘non-physical’) approaches. In addition, we show that the RFM can be used for accurate inference of various other quantities including genes' initiation rates and translation costs. These quantities could not be inferred by previous predictors. We find that increasing the number of available ribosomes (or equivalently the initiation rate) increases the genomic translation rate and the mean ribosome density only up to a certain point, beyond which both saturate. Strikingly, assuming that the translation system is tuned to work at the pre-saturation point maximizes the predictive power of the model with respect to experimental data. This result suggests that in all organisms that were analyzed (from bacteria to Human), the global initiation rate is optimized to attain the pre-saturation point. The fact that similar results were not observed for heterologous genes indicates that this feature is under selection. Remarkably, the gap between the performance of the RFM and alternative predictors is strikingly large in the case of heterologous genes, testifying to the model's promising biotechnological value in predicting the abundance of heterologous proteins before expressing them in the desired host