In 1990 Venezuela started its Program for the Promotion of Researchers (PPI), in order to foster research in science and technology A partial evaluation of the effects of the program on scientific and technological activities can be carried out using data from the System for :the Promotion of Researchers Foundation Fund (SPI). A complete and definitive evaluation is not possible, due to the fact t

Methods for solving index 3 DAEs based on BDFs suffer a loss of accuracy when there is a change of step size or a change of order of the method. A layer of nonuniform convergence is observed in these cases, and O(1) errors may appear in the algebraic variables. From the viewpoint of error control, it is beneficial to allow smooth changes of step size, and since most codes based on BDFs are of vari

Standard ODE methods such as linear multistep methods encounter difficulties when applied to differential-algebraic equations (DAEs) of index greater than 1. In particular, previous results for index 2 DAEs have practically ruled out the use of all explicit methods and of implicit multistep methods other than backward difference formulas (BDFs) because of stability considerations. In this paper we

Fundamental studies on combustion in laminar, nonpremixed flames are often carried out using conserved scalar quantities. These conserved scalar quantities, represented here by mixture fraction, E, are used as independent variables in activation-energy asymptotic analysis and in rate-ratio asymptotic analysis. These analyses are carried out in the asymptotic limit of large Damköhler number, with c

The present paper provides an extensive literature review on water related health issues in Central Asia. Even though the per capita amount of available freshwater is substantial in all Central Asian states the uneven distribution in time and space creates problems for water availability. Due to this, the Central Asian economies are developing under increasing water deficiency. The degradation of

Diiron complexes bearing redox active diamine ligands have been studied as models of the active site of [FeFe]-hydrogenases. Heating [Fe2(CO)6(μ-edt)] (edt = 1,2-ethanedithiolate) with 2,2′-bipyridine (2,2′-bipy) or 1,10-phenanthroline (1,10-phen) in MeCN in the presence of Me3NO leads to the formation of [Fe2(CO)4(κ2-2,2′-bipy)(μ-edt)] (1-edt) and [Fe2(CO)4(κ2-1,10-phen)(μ-edt)] (2-edt), respecti

Purpose The purpose of this paper was to assess the magnitude of the impact of construction-related rework on selected project budgets and schedule in public building construction in Uganda. The magnitude of construction-related rework was the mean determined over construction contracts under a selected project and expressed as a percentage of the construction contract sum. Design/methodology/appr

A novel rhodium(iii) complex [RhIII(H2LtBu)Cl3] (1) (H2LtBu = 2,6-bis(5-tert-butyl-1H-pyrazol-3-yl)pyridine) containing a pincer type, tridentate nitrogen-donor chelate system was synthesized. Single crystal X-ray structure analysis revealed that 1 crystallizes in the orthorhombic space group Pbcn with a = 20.7982(6), b = 10.8952(4), c = 10.9832(4) Å, V = 2488.80(15) Å3, and eight molecules in the

The Mesozoic biotas of Scandinavia have been studied for nearly two centuries. However, the last 15 years have witnessed an explosive advance in research, most notably on the richly fossiliferous Triassic (Olenekian-Carnian) and Jurassic (Tithonian) Lagerstätten of the Norwegian Arctic Svalbard archipelago, Late Cretaceous (Campanian) Kristianstad Basin and Vomb Trough of Skåne in southern Sweden,

Colloidal quantum dots (QDs) have attracted interest as materials for opto-electronic applications, wherein their efficient energy use requires the understanding of carrier relaxation. In QDs capped by bifunctional thiols, used to attach the QDs to a surface, the relaxation is complicated by carrier traps. Using 2D spectroscopy at 77 K, we follow excitations in thiol-capped CdSe QDs with state spe

Climate change may affect bird populations both directly by changing the weather conditions, and indirectly through changes in the food chain. While both theoretical and empirical studies have shown climate change having drastic impacts on polar areas, its consequences on Arctic bird species are still poorly known. Here we investigated how weather and changes in predator-prey interactions affected