Search results for "Processes"

Modelling Photoionisation in Isocytosine: Potential Formation of Longer‐Lived Excited State Cations in its Keto Form

2021

Abstract Studying the effects of UV and VUV radiation on non‐canonical DNA/RNA nucleobases allows us to compare how they release excess energy following absorption with respect to their canonical counterparts. This has attracted much research attention in recent years because of its likely influence on the origin of our genetic lexicon in prebiotic times. Here we present a CASSCF and XMS‐CASPT2 theoretical study of the photoionisation of non‐canonical pyrimidine nucleobase isocytosine in both its keto and enol tautomeric forms. We analyse their lowest energy cationic excited states including 2π+ , 2nO+ and 2nN+ and compare these to the corresponding electronic states in cytosine. Investigat…

Thaxtomin A-induced defense responses in Arabidopsis thaliana cells require an early Ca2+ influx

2008

International audience

Regional newspapers’ sourcing strategies: Changes in media-citation and self-citation from a longitudinal perspective

2018

In the light of profound transformation processes shaping news media markets during the last decade, in particular local and regional news markets are confronted with consolidation and concentration processes. As a result, newspaper organizations are required to adapt their organizational strategies and editorial routines to face these challenges. Among journalistic routines, the use of sources is a prime example for an analysis of changing patterns in news production. This article investigates regional newspaper’s use of self- and media-citations in a longitudinal design (1995, 2006, 2015). Based on a content analysis of German regional newspapers (N = 4713 articles), we illustrate changi…

Effect of the conversion of grassland to spring wheat field on the CO2 emission characteristics in Inner Mongolia, China

2007

Chinese grasslands have undergone great changes in land use in recent decades. Approximately 18.2% of the present arable land in China originated from the cultivation of grassland, but its impact on the carbon cycle has not been fully understood. This study wasconducted insitu for3yearstoassessthecomprehensive effects ofcultivationof temperatesteppe onsoilorganiccarbon(SOC) and soil respiration rates as well as ecosystem respiration. As compared with those in the Stipa baicalensis steppe, the SOC concentrations at depths of 0‐10 and 10‐20 cm in the spring wheat field were found to have decreased by 38.3 and 17.4% respectively from 29.5 and 21.9 g kg � 1 to 18.2 and 18.1 g kg � 1 after a cul…

Acoustic, perceptual and clinical studies of normal and dysphonic voice

1986

Voice research in Jyvaskyla during the last few years is reviewed. Some results from a number of studies are presented in terms of the variables investigated: background, clinical, perceptual and acoustic characteristics, and the relations between them. Acoustic studies of voice have been carried out by means of long-term average spectrum (LTAS) analysis.

2021

Abstract. Lignin oxidation products (LOPs) are widely used as vegetation proxies in climate archives, such as sediment and peat cores. The total LOP concentration, Σ 8, provides information on the abundance of vegetation, while the ratios C / V and S / V of the different LOP groups also provide information on the type of vegetation. Recently, LOP analysis has been successfully applied to speleothem archives. However, there are many open questions concerning the transport and microbial degradation of LOPs on their way from the soil into the cave system. These processes could potentially alter the original source-dependent LOP signals, in particular the C / V and S / V ratios, and thus compli…

New research in the methods and applications of sclerochronology

2017

Abstract Because the instrumental record is short and does not extend to periods before the initiation of significant human impacts, full understanding of the processes and dynamics involved in the modern phase of very rapid global change depends on the interpretation of high resolution and precisely dated proxy archives. The identification of very long-lived species of bivalve mollusc in the extratropical marine environment has been a crucial recent advance. These molluscs form patterns of periodic (usually annual) banding in their shells that are synchronous within populations, so that long (centennial and millennial) stacked chronologies can be built by crossdating from live collected to…

Succession et remplacements de communautés à brachiopodes en régime de sédimentation discontinue (Jurassique Moyen, Bourgogne, France)

1993

Abstract Sequence stratigraphy throws a new and seminal light on the fossil record and helps in determining the respective role played by external control (community replacement) and internal control (paleoecological succession) in the temporal “train” of marine benthic paleocommunities. Five brachiopod-dominated communities (C1–C5) are recognized and their temporal “train” described, during the uppermost Bathonian-lower Callovian interval in Burgundy. The first series (C1–C3) exhibits a trend interpreted as a paleoecological succession and the next two (C3–C4, C4–C5) as community replacements. Within the scope of sequence stratigraphy, the paleoecological succession comes at the end of a t…

Forms and Processes of Settlement Pressure on Natural Systems

2021

The process of urbanisation is considered one of the most significant anthropic alterations of the environmental framework, and the present study attempts to understand the spatial characteristics of urban growth and their impacts on envi- ronmental components in two metropolitan areas of Sicily. Such rapid and unplanned urbanisation in Sicily has increased during the last three decades causing severe pres- sure on various natural resources. In this situation, the level of fragmentation and isolation of natural areas risks becoming worse. The question assumes a particular relevance in those local territorial portions, such as some urban and periurban areas, presenting relevant conditions of…

An investigation of Facebook users' implicit associations between Facebook, sexual and prosocial behavior.

2018

Abstract Despite growing research on online social networking, implicit associations of Facebook users have been largely understudied. In Study 1, we used the Single-Target Implicit Association Test (ST-IAT; Karpinski and Steinman, 2006) in order to assess implicit associations between Facebook and two evolutionary relevant constructs: sexual and prosocial behavior. Additionally, we controlled for the role of participant's relationship status as a potential moderator of Facebook implicit associations. In Study 2, we extended these findings and explored the relationship between implicit and explicit associations towards Facebook. Across two studies, we found that Facebook is more strongly as…