Propriétés spectroscopiques de U4+ dans ThBr4

L'indexation de raies à zéro phonon du spectre d'absorption de ThBr4 : U4+ est discutée, compte tenu du spectre de vibration de la matrice et des spectres d'émission de ces monocristaux excites par laser

2-Hydr­oxy-5-nitro­benzaldehyde 2,4-dinitro­phenyl­hydrazone

In the title compound, C13H9N5O7, one of the nitro groups is twisted away from the attached benzene ring by 16.21 (8)°. The dihedral angle between the two benzene rings is 4.63 (1)°. The mol­ecular structure is stabilized by intra­molecular N—H⋯O and O—H⋯N hydrogen bonds which generate an S(6) ring motif. The mol­ecules pack as layers parallel to the ab plane; mol­ecules of adjacent layers are linked into chains along the [101] direction through N—H⋯O hydrogen bonds

Aid to conflict-affected countries : lessons for donors

The first section looks at the implications of conflict for aid effectiveness and selectivity. We argue that, while aid is generally effective in promoting growth and by implication reducing poverty, it is more effective in promoting growth in post-conflict countries. We then consider the implications of these findings for donor selectivity models and for assessment of donor performance in allocating development aid among recipient countries. We argue that, while further research on aid effectiveness in post-conflict scenarios is needed, existing selectivity models should be augmented with, inter alia, post-conflict variables, and donors should be evaluated on the basis, inter alia, of the share of their aid budgets allocated to countries experiencing post-conflict episodes. We also argue for aid delivered in the form of projects to countries with weak institutions in early post-conflict years. The second section focuses on policies for donors operating in conflict-affected countries. We set out five of the most important principles: (1) focus on broad-based recovery from war; (2) to achieve a broad-based recovery, get involved before the conflict ends; (3) focus on poverty, but avoid &lsquo;wish lists&rsquo;; (4) help to reduce insecurity so aid can contribute more effectively to growth and poverty reduction; and (5) in economic reform, focus on improving public expenditure management and revenue mobilisation. The third section concludes by emphasising the fact that there is no hard or fast dividing line between &lsquo;war&rsquo; and &lsquo;peace&rsquo; and that it may take many years for a society to become truly &lsquo;post&rsquo;-conflict&rsquo;. Donors, therefore, need to prepare for the long haul.<br /

Photoswitchable fluorescent diheteroarylethenes: substituent effects on photochromic and solvatochromic properties

Photoswitchable fluorescent diheteroarylethenes are promising candidates for applications in super-resolution molecular localization fluorescence microscopy thanks to their high quantum yields and fatigue-resistant photoswitching characteristics. We have studied the effect of varying substituents on the photophysical properties of six sulfone derivatives of diheteroarylethenes, which display fluorescence in one (closed form) of two thermally stable photochromic states. Electron-donating substituents displace the absorption and emission spectra towards the red without substantially affecting the fluorescence quantum yields. Furthermore, ethoxybromo, a very electron-donating substituent, stabilizes the excited state of the closed isomer to the extent of almost entirely inhibiting its cycloreversion. Multi-parameter Hammett correlations indicate a relationship between the emission maxima and electron-donating character, providing a useful tool in the design of future photochromic molecules. Most of the synthesized compounds exhibit small bathochromic shifts and shorter fluorescence lifetimes with an increase in solvent polarity. However, the ethoxybromo-substituted fluorescent photochrome is unique in its strong solvatochromic behaviour, constituting a photoactivatable (photochromic), fluorescent and highly solvatochromic small organic compound. The Catalán formalism identified solvent dipolarity as the principal basis of the solvatochromism, reflecting the highly polarized nature of this molecule.Fil: Gillanders, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Max Planck Institute for Biophysical Chemistry. Laboratory of Cellular Dynamics; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Giordano, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Max Planck Institute for Biophysical Chemistry. Laboratory of Cellular Dynamics; AlemaniaFil: Diaz, Sebastian Andres. Max Planck Institute for Biophysical Chemistry. Laboratory of Cellular Dynamics; AlemaniaFil: Jovin, Tomás. Max Planck Institute for Biophysical Chemistry. Laboratory of Cellular Dynamics; AlemaniaFil: Jares, Elizabeth Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentin

The impact of foreign direct investment, foreign aid and trade on poverty reduction : evidence from Sub-Saharan African countries

Abstract:Despite postulations on the effects of foreign direct investment (FDI), foreign aid, and trade on growth, empirical evidence from extant research has been mixed. The focus of recent research has shifted from the growth effects of these international flows to their poverty reduction effects. However, results have also been mixed. Most studies have examined the empirical evidence of these flows separately and have mostly conducted single country studies. In this study, we use data from twenty-nine countries in Sub-Saharan Africa between the period 1990–2017 to analyze the effects of FDI, trade, and foreign aid on poverty reduction in a single model using the Feasible Generalized Least Square (FGLS) technique. Our results show that FDI and foreign aid have a negative effect on poverty reduction in the countries studied. These results suggest that the level of FDI required to alleviate poverty has not been reached, and foreign aid have not been properly channeled. However, the results show that trade has a positive and significant impact on poverty reduction, especially in low-income countries. We conclude with policy recommendations

Donors, Aid and Taxation in Developing Countries: An Overview

Recent years have witnessed rapidly growing donor interest in tax issues in the developing world. This reflects a concern with revenue collection to finance public spending, but also recognition of the centrality of taxation to growth, redistribution and broader state-building and governance goals. Against this backdrop, this paper identifies a series of key issues that demand attention if donors are to improve the quality of their support for tax reform. The focus is not, primarily, on the technical design of tax interventions, but, instead, on seven ‘big picture’ considerations for the design of donor programmes: (a) supporting local leadership of reform efforts; (b) incorporating more systematic political economy analysis into the design and implementation of reform programmes; (c) designing tax reform programmes that seek to foster broader linkages between taxation, state-building and governance; (d) paying careful attention to the complexity of the relationship between aid and tax effort; (e) better designing tax-related conditionality, particularly by developing a more nuanced set of performance indicators; (f) ensuring the effective coordination of donor interventions; and (g) paying greater attention to the international policy context, and particularly the role of tax exemptions for donor projects, tax havens and tax evasion by multinational corporations (MNCs) in undermining developing country tax systems.DfI