229 research outputs found
European differences in executive pay andcorporate governance
This paper examines the level and stmcture of executive pay across a sample of European economies in the mid- 1990s. Our results indicate that there are significant differences in executive pay across Europe which are explained in large part by the particular job position and Company size. However, after Controlling for these factors we find that country specific effects are important in executive pay determination. Our cross section results indicate that country effects on pay are not wholly eradicated by the effects of the internationalisation of capital and labour markets through factor price equalisation. The effects of different board structures on executive pay turns out to be ambiguous in our sample.Not Reviewe
Energy Starved Candidatus Pelagibacter Ubique Substitutes Light-Mediated ATP Production for Endogenous Carbon Respiration
Previous studies have demonstrated that Candidatus Pelagibacter ubique, a member of the SAR11 clade, constitutively expresses proteorhodopsin (PR) proteins that can function as light-dependent proton pumps. However, exposure to light did not significantly improve the growth rate or final cell densities of SAR11 isolates in a wide range of conditions. Thus, the ecophysiological role of PR in SAR11 remained unresolved. We investigated a range of cellular properties and here show that light causes dramatic changes in physiology and gene expression in Cand. P. ubique cells that are starved for carbon, but provides little or no advantage during active growth on organic carbon substrates. During logarithmic growth there was no difference in oxygen consumption by cells in light versus dark. Energy starved cells respired endogenous carbon in the dark, becoming spheres that approached the minimum predicted size for cells, and produced abundant pili. In the light, energy starved cells maintained size, ATP content, and higher substrate transport rates, and differentially expressed nearly 10% of their genome. These findings show that PR is a vital adaptation that supports Cand. P. ubique metabolism during carbon starvation, a condition that is likely to occur in the extreme conditions of ocean environments
3-methylhistidine as an Indicator for Protein Beakdown: An Experimental Model in Male Capra hircu
The role of the amino acid 3-methylhistidine as an indicator of protein breakdown and weight loss is often suggested. Despite existing information for other animal species, little is known about the actual levels of 3-methyhistidine in the serum of less studied domestic species such as the goat. We have evaluated the 3-methyhistidine serum concentrations in young Boer goat bucks subjected to two distinct feeding regimens: winter-grass hay with or without supplementation. Non-supplemented animals had a negative nitrogen balance and experienced weight loss throughout the experiment and significantly higher concentrations of 3-methyhistidine than supplemented animals that had a slight increase in live weight. This amino acid can be considered a valid indicator of protein breakdown and weight decrease in male goats. Serum 3-methylhistidine concentrations in adequately fed male goats were similar throughout the assay (20-40 μmol/l) whereas in weight-losing animals, concentrations of up to 170μmol/l can be expected.
Identification of candidate structured RNAs in the marine organism 'Candidatus Pelagibacter ubique'
<p>Abstract</p> <p>Background</p> <p>Metagenomic sequence data are proving to be a vast resource for the discovery of biological components. Yet analysis of this data to identify functional RNAs lags behind efforts to characterize protein diversity. The genome of '<it>Candidatus </it>Pelagibacter ubique' HTCC 1062 is the closest match for approximately 20% of marine metagenomic sequence reads. It is also small, contains little non-coding DNA, and has strikingly low GC content.</p> <p>Results</p> <p>To aid the discovery of RNA motifs within the marine metagenome we exploited the genomic properties of '<it>Cand</it>. P. ubique' by targeting our search to long intergenic regions (IGRs) with relatively high GC content. Analysis of known RNAs (rRNA, tRNA, riboswitches etc.) shows that structured RNAs are significantly enriched in such IGRs. To identify additional candidate structured RNAs, we examined other IGRs with similar characteristics from '<it>Cand</it>. P. ubique' using comparative genomics approaches in conjunction with marine metagenomic data. Employing this strategy, we discovered four candidate structured RNAs including a new riboswitch class as well as three additional likely <it>cis</it>-regulatory elements that precede genes encoding ribosomal proteins S2 and S12, and the cytoplasmic protein component of the signal recognition particle. We also describe four additional potential RNA motifs with few or no examples occurring outside the metagenomic data.</p> <p>Conclusion</p> <p>This work begins the process of identifying functional RNA motifs present in the metagenomic data and illustrates how existing completed genomes may be used to aid in this task.</p
Recent developments in the Dutch firm-size distribution
This study investigates the development of the firm-size distribution in the Netherlands using various measures. Data are used for the period 1978 through 1989 covering practically the entire Dutch private sector. The results show a general tendency towards smaller firm sizes in manufacturing industries until 1986, but indicate an opposite development after that year. This tendency towards larger firm sizes after 1986 is also encountered for non-manufacturing industries.
This study is part of a research program carried out at the Centre for Advanced Small Business Economics (CASBEC) of the Erasmus University Rotterdam. The authors are grateful to Jan van Dalen, Aad Kleijweg, Jeroen Potjes and Wim Verhoeven for helpful comments and Herman van Schaik for elaborating the original data files. The authors acknowledge a research grant from the Stichting KMO-fonds
Transcriptional and Translational Regulatory Responses to Iron Limitation in the Globally Distributed Marine Bacterium Candidatus Pelagibacter ubique
Iron is recognized as an important micronutrient that limits microbial plankton productivity over vast regions of the oceans. We investigated the gene expression responses of Candidatus Pelagibacter ubique cultures to iron limitation in natural seawater media supplemented with a siderophore to chelate iron. Microarray data indicated transcription of the periplasmic iron binding protein sfuC increased by 16-fold, and iron transporter subunits, iron-sulfur center assembly genes, and the putative ferroxidase rubrerythrin transcripts increased to a lesser extent. Quantitative peptide mass spectrometry revealed that sfuC protein abundance increased 27-fold, despite an average decrease of 59% across the global proteome. Thus, we propose sfuC as a marker gene for indicating iron limitation in marine metatranscriptomic and metaproteomic ecological surveys. The marked proteome reduction was not directly correlated to changes in the transcriptome, implicating post-transcriptional regulatory mechanisms as modulators of protein expression. Two RNA-binding proteins, CspE and CspL, correlated well with iron availability, suggesting that they may contribute to the observed differences between the transcriptome and proteome. We propose a model in which the RNA-binding activity of CspE and CspL selectively enables protein synthesis of the iron acquisition protein SfuC during transient growth-limiting episodes of iron scarcity
Serum progesterone as an indicator of cyclic activity in post-partum goat does
___________________________________________________________________________________ Abstract The aim of this trial was to assess post-partum ovarian activity of the does of two South African goat breeds from their serum progesterone concentrations. Between seven and 100 days post-partum, does from the Boer goat breed and an indigenous rural goat type were allocated to two nutritional treatments within breed. One group per breed received a concentrated diet in an intensive feeding programme. The other group per breed was subjected to a low level of nutrition through the grazing of the natural pasture in an extensive (veld) grazing system. Blood samples were collected weekly from five does per breed per treatment. Serum progesterone concentrations were determined using a Gamma Coat TM [128] progesterone radioimmunoassay kit (Sorin Diagnostics, France). Large variations in serum progesterone concentrations were recorded within and between breeds and nutritional regimens. Irrespective of breed, in the extensive groups subjected to the low level of nutrition, mean peak serum progesterone concentrations never exceeded 0.2 ng/mL. This suggests that throughout the experimental period, ovarian activity remained low in the extensive groups. It was concluded that nutritional regimen plays a significant role in ensuring high ovarian activities. Furthermore, the higher mean serum progesterone levels in the Boer goat indicate an earlier and higher oestrous activity, compared to the indigenous does. __________________________________________________________________________________
OC 8535 An overview of research ethics committees operating in lusophone african countries
Background: In 2017, a North-South partnership was created, to strengthen Bioethics Committees in African Lusophone African countries (LAC), by joining the forces of National and Institutional Research Ethics Committees (REC) and Universities in Angola, Cape Verde, Mozambique and Portugal. This study is part of an EDCTP2-funded project and aims to describe key RECs operating in LAC, its establishment dates and further characteristics. Methods: Document analysis and interviews with REC representatives of five LAC were conducted in April 2018. Legal documents were obtained through official national sources. Results: We identified four National Ethics Committees, created between 2000 and 2008 by ministerial or governmental decree; only S. Tomé e Principe does not have an established REC. In Angola, the National REC was created in 2000, and since 2007, seven Institutional Committees were implemented at faculty level. National REC in Cape Verde and Guinee-Bissau (CNES) are unique and were founded in 2007 and 2009 respectively. In Mozambique, National REC (CNBS) dates to 2002, and since 2011, 8 Institutional Committees were formed; they functioned as a network under the umbrella of CNBS. Most National REC have representatives from health professional associations, lawyers, civil society and religious communities and have regular meetings (usually monthly). The number of members ranges between 6 (CNES) and 13 (CNBS). In 2007, around 200 protocols were reviewed by CNBS and 29 by CNES. Most of the National REC members attended training activities in bioethics but at different levels. Conclusion: Few publications described REC operating in LAC; this study fills this gap by reporting historical and functional characteristics of RECs in five Lusophone African countries. Additional tools based on quantitative and qualitative approaches are being developed to assess more in-depth REC operational characteristics and to identify their needs in order to target training and capacity building initiatives underlying our project.publishersversionpublishe
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