58 research outputs found
The Complex Investigation of the Stone Artefacts from Vatya-Earthworks of Fejér County. Part I.
Transforming Traditions of Material Culture : Spatial and temporal patterns in pottery style, production and use during the second half of the 6th millennium cal BC in south-eastern Transdanubia and beyond
International audienceOne of the most salient traits of a major milestone in European history, the shift to a Neolithic life-style in Central Europe and the associated social changes, was the emergence of pottery production. The main goal of the research project described here is the study of Neolithic pottery production from a complex perspec- tive and the addressing of the associated distinctive social activity types and potential range of meanings during the period from the late Starčevo to the appearance of the Lengyel culture (5500–4900 cal BC). The springboard for our project was the series of intensely investigated sites in southern Transdanubia, a region that acted as a contact zone between the Neolithic communities of Central Europe and the northern Balkans, and thus played a key role in the neolithisation of Central Europe. The research findings from this region are complemented and compared with the data from various sites along the Danube. Aside from our academic colleagues, our research results can be of interest to the broader public too, and our reconstruc- tions of various artefacts and the documentation of our archaeological experiments can be later used as illustrations to museum exhibits. The expected results can be fitted into the broad picture outlined by other research conducted on these sites and offer an exceptionally detailed picture of how the region’s settlements developed during the second half of the 6th millennium BC
The AtCRK5 Protein Kinase Is Required to Maintain the ROS NO Balance Affecting the PIN2-Mediated Root Gravitropic Response in Arabidopsis
The Arabidopsis AtCRK5 protein kinase is involved in the establishment of the proper auxin gradient in many developmental processes. Among others, the Atcrk5-1 mutant was reported to exhibit a delayed gravitropic response via compromised PIN2-mediated auxin transport at the root tip. Here, we report that this phenotype correlates with lower superoxide anion (O-2(center dot-)) and hydrogen peroxide (H2O2) levels but a higher nitric oxide (NO) content in the mutant root tips in comparison to the wild type (AtCol-0). The oxidative stress inducer paraquat (PQ) triggering formation of O-2(center dot-) (and consequently, H2O2) was able to rescue the gravitropic response of Atcrk5-1 roots. The direct application of H2O2 had the same effect. Under gravistimulation, correct auxin distribution was restored (at least partially) by PQ or H2O2 treatment in the mutant root tips. In agreement, the redistribution of the PIN2 auxin efflux carrier was similar in the gravistimulated PQ-treated mutant and untreated wild type roots. It was also found that PQ-treatment decreased the endogenous NO level at the root tip to normal levels. Furthermore, the mutant phenotype could be reverted by direct manipulation of the endogenous NO level using an NO scavenger (cPTIO). The potential involvement of AtCRK5 protein kinase in the control of auxin-ROS-NO-PIN2-auxin regulatory loop is discussed
129I and 247Cm in meteorites constrain the last astrophysical source of solar r-process elements
Meteoritic analysis demonstrates that radioactive nuclei heavier than iron were present in the early Solar System. Among them, I and Cm both have a rapid neutron-capture process ( process) origin and decay on the same timescale ( 15.6 Myr). We show that the I/Cm abundance ratio in the early Solar System (438184) is immune to galactic evolution uncertainties and represents the first direct observational constraint for the properties of the last -process event that polluted the pre-solar nebula. We investigate the physical conditions of this event using nucleosynthesis calculations and demonstrate that moderately neutron-rich ejecta can produce the observed ratio. We conclude that a dominant contribution by exceedingly neutron-rich ejecta is highly disfavoured
129I and 247Cm in meteorites constrain the last astrophysical source of solar r-process elements
Változó tradíciók. A kerámiastílus, -előállítás és -használat tér- és időbeli mintázatai a Kr. e. 6. évezred második felében a Délkelet-Dunántúlon és a környező régiókban
International audienc
Organic residues in archaeology - the highs and lows of recent research
YesThe analysis of organic residues from archaeological materials has become increasingly important to our understanding of ancient diet, trade and technology. Residues from diverse contexts have been retrieved and analysed from the remains of food, medicine and cosmetics to hafting material on stone arrowheads, pitch and tar from shipwrecks, and ancient manure from soils. Research has brought many advances in our understanding of archaeological, organic residues over the past two decades. Some have enabled very specific and detailed interpretations of materials preserved in the archaeological record. However there are still areas where we know very little, like the mechanisms at work during the formation and preservation of residues, and areas where each advance produces more questions rather than answers, as in the identification of degraded fats. This chapter will discuss some of the significant achievements in the field over the past decade and the ongoing challenges for research in this area.Full text was made available in the Repository on 15th Oct 2015, at the end of the publisher's embargo period
Spontaneous doping of the basal plane of MoS2 single layers through oxygen substitution under ambient conditions
The chemical inertness of the defect-free basal plane confers environmental
stability to MoS2 single-layers, but it also limits their chemical versatility
and catalytic activity. The stability of the pristine MoS2 basal plane against
oxidation under ambient conditions is a widely accepted assumption in the
interpretation of various studies and applications. However, single-atom level
structural investigations reported here reveal that oxygen atoms spontaneously
incorporate into the basal plane of MoS2 single layers during ambient exposure.
Our scanning tunneling microscopy investigations reveal a slow oxygen
substitution reaction, upon which individual sulfur atoms are one by one
replaced by oxygen, giving rise to solid solution type 2D MoS2-xOx crystals. O
substitution sites present all over the basal plane act as single-atomic active
reaction centers, substantially increasing the catalytic activity of the entire
MoS2 basal plane for the electrochemical H2 evolution reaction.Comment: 6 pages, 5 figure
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