Follow the leader : on the relationship between leadership and scholarly impact in international collaborations

National contributions to science are influenced by a number of factors, including economic capacity, national scientific priorities, science policy, and institutional settings and cultures. Nations do not have equal opportunities to access the global scientific market, and therefore, often seek out international partners with complementary resources and expertise. This study aims at investigating national collaboration strategies, with a focus on research leadership—measured through corresponding authorship—and its relationship with scientific impact. Results show that countries with higher R&D investments are more scientifically independent, and confirm that international collaboration is positively related to citation impact. However, leadership in international collaboration is inversely related with a countries’ share of international collaboration and there is a very little relationship between citation impact and international leadership. For instance, most countries—and particularly those that have fewer resources—have higher scientific impact when they are not leading. This suggests that, despite increasing global participation in science, most international collaborations are asymmetrical, and that the research system remains structured around a few dominate nations

Fluid Evolution in the Patricia Zn-Pb-Ag vein deposit (Paguanta, NE Chile): fluid inclusion assemblages and laser ablation ICP-MS evidence

The Patricia Zn-Pb-Ag ore deposit represents the first known example of economic mineralization in the northern part of the Andean late Eocene – Oligocene metallogenic belt in Chile. The hydrothermal evolution has been deduced based on detailed mineralogy, fluid inclusion petrography, microthermometry and laser ablation ICP-MS analysis. We present microthermometric data for fluid inclusion assemblages (FIAs) in co-genetic ore and gangue minerals through the different mineralization stages. In the pre-ore stage, early quartzhosted FIAs indicate high salinity values (22 to 6 wt.% NaCl) with homogenization temperatures from 270 to 205ºC. During the base metal and silver stage, a drop in temperature from 250 to 140 ºC and salinity less than 10 wt.% NaCl is related to the main ore precipitation. Primary FIAs in the post-ore stage indicate temperature up to 245ºC and low salinity (4 to 3 wt.% NaCl). The LAICP- MS analyses of fluid inclusions show that the metal content in the base metal stage is significantly higher than in the pre-ore and post-ore stages. This study documents the existence of different fluid pulses characterized by cooling and low salinity conditions favourable for the main ore deposition during the base metal and silver stage. The ore mineralogy and the associated hydrothermal alteration define the Patricia ore as an intermediate-sulfidation epithermal deposit with low-sulfidation events.This research was funded by the Spanish research project CGL-2010-17668.Peer reviewe

An empirical review of the different variants of the Probabilistic Affinity Index as applied to scientific collaboration

Responsible indicators are crucial for research assessment and monitoring. Transparency and accuracy of indicators are required to make research assessment fair and ensure reproducibility. However, sometimes it is difficult to conduct or replicate studies based on indicators due to the lack of transparency in conceptualization and operationalization. In this paper, we review the different variants of the Probabilistic Affinity Index (PAI), considering both the conceptual and empirical underpinnings. We begin with a review of the historical development of the indicator and the different alternatives proposed. To demonstrate the utility of the indicator, we demonstrate the application of PAI to identifying preferred partners in scientific collaboration. A streamlined procedure is provided, to demonstrate the variations and appropriate calculations. We then compare the results of implementation for five specific countries involved in international scientific collaboration. Despite the different proposals on its calculation, we do not observe large differences between the PAI variants, particularly with respect to country size. As with any indicator, the selection of a particular variant is dependent on the research question. To facilitate appropriate use, we provide recommendations for the use of the indicator given specific contexts.Comment: 35 pages, 3 figures, 5 table

Cyclin-Dependent Kinase-Like Function Is Shared by the Beta- and Gamma- Subset of the Conserved Herpesvirus Protein Kinases

The UL97 protein of human cytomegalovirus (HCMV, or HHV-5 (human herpesvirus 5)), is a kinase that phosphorylates the cellular retinoblastoma (Rb) tumor suppressor and lamin A/C proteins that are also substrates of cellular cyclin-dependent kinases (Cdks). A functional complementation assay has further shown that UL97 has authentic Cdk-like activity. The other seven human herpesviruses each encode a kinase with sequence and positional homology to UL97. These UL97-homologous proteins have been termed the conserved herpesvirus protein kinases (CHPKs) to distinguish them from other human herpesvirus-encoded kinases. To determine if the Cdk-like activities of UL97 were shared by all of the CHPKs, we individually expressed epitope-tagged alleles of each protein in human Saos-2 cells to test for Rb phosphorylation, human U-2 OS cells to monitor nuclear lamina disruption and lamin A phosphorylation, or S. cerevisiae cdc28-13 mutant cells to directly assay for Cdk function. We found that the ability to phosphorylate Rb and lamin A, and to disrupt the nuclear lamina, was shared by all CHPKs from the beta- and gamma-herpesvirus families, but not by their alpha-herpesvirus homologs. Similarly, all but one of the beta and gamma CHPKs displayed bona fide Cdk activity in S. cerevisiae, while the alpha proteins did not. Thus, we have identified novel virally-encoded Cdk-like kinases, a nomenclature we abbreviate as v-Cdks. Interestingly, we found that other, non-Cdk-related activities reported for UL97 (dispersion of promyelocytic leukemia protein nuclear bodies (PML-NBs) and disruption of cytoplasmic or nuclear aggresomes) showed weak conservation among the CHPKs that, in general, did not segregate to specific viral families. Therefore, the genomic and evolutionary conservation of these kinases has not been fully maintained at the functional level. Our data indicate that these related kinases, some of which are targets of approved or developmental antiviral drugs, are likely to serve both overlapping and non-overlapping functions during viral infections

The LHC Logging Service : Handling terabytes of on-line data

Based on previous experience with LEP, a long-term data logging service for the LHC was developed and put in place in 2003, several years before beam operation. The scope of the logging service covers the evolution over time of data acquisitions on accelerator equipment and beam related parameters. The intention is to keep all this time-series data on-line for the lifetime of LHC, allowing easy data comparisons with previous years. The LHC hardware commissioning has used this service extensively prior to the first beams in 2008 and even more so in 2009. Current data writing rates exceed 15TB/year and continue to increase. The high data volumes and throughput rates, in writing as well as in reading, require special arrangements on data organization and data access methods

Bis(1-tosyl-2-pyrrol­yl)ethyne

The title mol­ecule, C24H20N2O4S2, has crystallographic inversion symmetry with a triple-bond distance of 1.206 (2) Å. The alkyne is not quite linear, with a C—C C angle of 175.78 (16)°. The planar pyrrole rings are parallel but offset from coplanarity by 0.318 (1) Å. The conformation of the sulfonyl group with respect to the pyrrole ring is such that an O atom is nearly eclipsed with this ring, having an O—S—N—C torsion angle of 3.48 (11)°. C—H⋯O inter­actions [C⋯O 3.278 (2) Å, 136° about H] between pyrrole H and sulfonyl O atoms lead to the formation of ladder-like chains