225 research outputs found
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
The morphology of human rod ERGs obtained by silent substitution stimulation
YesPurpose To record transient ERGs from the lightadapted
human retina using silent substitution stimuli
which selectively reflect the activity of rod photoreceptors.
We aim to describe the morphology of these
waveforms and examine how they are affected by the
use of less selective stimuli and by retinal pathology.
Methods Rod-isolating stimuli with square-wave
temporal profiles (250/250 ms onset/offset) were
presented using a 4 primary LED ganzfeld stimulator.
Experiment 1: ERGs were recorded using a rodisolating
stimulus (63 ph Td, rod contrast,
Crod = 0.25) from a group (n = 20) of normal
trichromatic observers. Experiment 2: Rod ERGs
were recorded from a group (n = 5) using a rodisolating
stimulus (Crod = 0.25) which varied in
retinal illuminance from 40 to 10,000 ph Td. Experiment
3: ERGs were elicited using 2 kinds of nonisolating
stimuli; (1) broadband and (2) rod-isolating
stimuli which contained varying degrees of L- and
M-cone excitation. Experiment 4: Rod ERGs were
recorded from two patient groups with rod monochromacy
(n = 3) and CSNB (type 1; n = 2).
Results The rod-isolated ERGs elicited from normal
subjects had a waveform with a positive onset
component followed by a negative offset. Response
amplitude was maximal at retinal illuminances\100
ph Td and was virtually abolished at 400 ph Td. The
use of non-selective stimuli altered the ERG waveform
eliciting more photopic-like ERG responses. Rod
ERGs recorded from rod monochromats had similar
features to those recorded from normal trichromats, in
contrast to those recorded from participants with
CSNB which had an electronegative appearance.
Conclusions Our results demonstrate that ERGs
elicited by silent substitution stimuli can selectively
reflect the operation of rod photoreceptors in the
normal, light-adapted human retina.Deutsche Forschungsgemeinschaft (DFG) (KR1317/13-1) and Bundesministerium für Bildung und Forschung (BMBF) (01DN14009) provided financial support for JK
The Presidency and the Executive Branch in Latin America: What We Know and What We Need to Know
The presidential politics literature depicts presidents either as all- powerful actors or figureheads and seeks to explain outcomes accordingly. Th e president and the executive branch are nonetheless usually treated as black boxes, particularly i n developing countries, even though the presidency has evolved into an extremely complex branch of government. While these developments have been studied in the U nited States, far less i s known in other countries, particularly in Latin America, where presi dential systems have been considered the source of all goods and evils. To help close the knowledge gap and explore differences in policymaking characteristics not only between Latin America and the US but also across Latin American countries, this paper s ummarizes the vast literature on the organization and resources of the Executive Branch in the Americas and sets a research agenda for the study of Latin American presidencies.Fil: Bonvecchi, Alejandro. Universidad Torcuato Di Tella. Departamento de Ciencia PolÃtica y Estudios Internacionales; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Scartascini, Juan Carlos. Banco Interamericano de Desarrollo; Estados Unido
The Politics of Federalism in Argentina: Implications for Governance and Accountability
Ecologically Appropriate Xenobiotics Induce Cytochrome P450s in Apis mellifera
BACKGROUND: Honey bees are exposed to phytochemicals through the nectar, pollen and propolis consumed to sustain the colony. They may also encounter mycotoxins produced by Aspergillus fungi infesting pollen in beebread. Moreover, bees are exposed to agricultural pesticides, particularly in-hive acaricides used against the parasite Varroa destructor. They cope with these and other xenobiotics primarily through enzymatic detoxificative processes, but the regulation of detoxificative enzymes in honey bees remains largely unexplored. METHODOLOGY/PRINCIPAL FINDINGS: We used several approaches to ascertain effects of dietary toxins on bee susceptibility to synthetic and natural xenobiotics, including the acaricide tau-fluvalinate, the agricultural pesticide imidacloprid, and the naturally occurring mycotoxin aflatoxin. We administered potential inducers of cytochrome P450 enzymes, the principal biochemical system for Phase 1 detoxification in insects, to investigate how detoxification is regulated. The drug phenobarbital induces P450s in many insects, yet feeding bees with phenobarbital had no effect on the toxicity of tau-fluvalinate, a pesticide known to be detoxified by bee P450s. Similarly, no P450 induction, as measured by tau-fluvalinate tolerance, occurred in bees fed xanthotoxin, salicylic acid, or indole-3-carbinol, all of which induce P450s in other insects. Only quercetin, a common pollen and honey constituent, reduced tau-fluvalinate toxicity. In microarray comparisons no change in detoxificative gene expression was detected in phenobarbital-treated bees. However, northern blot analyses of guts of bees fed extracts of honey, pollen and propolis showed elevated expression of three CYP6AS P450 genes. Diet did not influence tau-fluvalinate or imidacloprid toxicity in bioassays; however, aflatoxin toxicity was higher in bees consuming sucrose or high-fructose corn syrup than in bees consuming honey. CONCLUSIONS/SIGNIFICANCE: These results suggest that regulation of honey bee P450s is tuned to chemicals occurring naturally in the hive environment and that, in terms of toxicological capacity, a diet of sugar is not equivalent to a diet of honey
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