3,348 research outputs found
Globalization, Growth, Inequality and Poverty in Africa: A Macroeconomic Perspective
The last two decades has witnessed an increase in globalizing influences affecting most countries, Africa included. These influences have arisen partly as a result of domestic and international policies, such as trade policies, and partly as a result of general globalizing impulses, such as technological developments and enhanced communications. The single overarching objective of this paper is to outline the macro evidence on the extent to which globalization is taking place and poverty is reducing in Africa, and to consider this to both characteristics of the region (i.e., within the region) and relative to other global regions. It draws on some of the most recent evidence about the globalizing processes in various forms so as to try to determine the speed and extent of globalization in Africa. This helps to put into proper perspective the impact of globalization on poverty and inequality. It is essentially a partial and descriptive approach, at best indicative of associations, and stops short of attempting to identify, empirically, channels of influence and causal relationships.globalization, inequality, poverty, Sub-Saharan Africa
Determinants of Income Inequality and its Effects on Economic Growth: Evidence from African Countries
Income distribution, Income inequality, Economic growth
Aid Effort and its Determinants
determinants of aid efforts, generosity, ODA, DAC, donors, G7
Carbon Capture and Storage: Wishful Thinking or a Meaningful Part of the Climate Change Solution
In the lead-up to the climate change negotiations that are scheduled to take place in Copenhagen towards the end of 2009, pursuant to the United Nations Framework Convention on Climate Change, and in order to reach agreement on a post-Kyoto Protocol international climate change regime, many countries around the globe are considering the options available to them to reduce greenhouse gas (GHG) emissions in a manner that will minimize the cost impacts to economies already battered from the onslaught of the 2008 global financial crisis. In addition to confronting a markedly changed geopolitical landscape including the election of a new administration in the United States under the Democrats and President Barack Obama, the ongoing military confrontation between Hamas and the Israelis in Gaza, an outbreak of terrorist attacks in Mumbai, and Iran drawing ever closer to the possible development of nuclear weapons, the international community is facing what is predicted by some to be the most severe and prolonged economic downturn since the 1930s and the Great Depression. The collapse of the banking systems in several countries triggered in part by the sub-prime [*422] mortgage crisis in the United States has inevitably led to a credit crisis around the globe as job layoffs are expected to climb throughout 2009 and into 2010.
The impact of these events on the ability of the international community to address the climate change challenges that lie ahead is fraught with uncertainty and the reluctance of the world's major coal producers to abandon or curtail an industry of vital economic importance in terms of both jobs and exports, has elevated carbon capture and storage (CCS) to increasing levels of importance in the consideration of available energy options. It remains to be seen whether the attention and investment dollars presently committed to the development of CCS technologies around the globe is warranted. This paper will endeavor to outline how CCS is currently viewed by Australia and the European Union as part of their respective energy strategies
Double white dwarf mergers and elemental surface abundances in extreme helium and R Coronae Borealis stars
The surface abundances of extreme helium (EHe) and R Coronae Borealis (RCB)
stars are discussed in terms of the merger of a carbon-oxygen white dwarf with
a helium white dwarf. The model is expressed as a linear mixture of the
individual layers of both constituent white dwarfs, taking account of the
specific evolution of each star. In developing this recipe from previous
versions, particular attention has been given to the inter-shell abundances of
the asymptotic giant branch star which evolved to become the carbon-oxygen
white dwarf. Thus the surface composition of the merged star is estimated as a
function of the initial mass and metallicity of its progenitor. The question of
whether additional nucleosynthesis occurs during the white dwarf merger has
been examined.
The high observed abundances of carbon and oxygen must either originate by
dredge-up from the core of the carbon-oxygen white dwarf during a cold merger
or be generated directly by alpha-burning during a hot merger. The presence of
large quantities of O18 may be consistent with both scenarios, since a
significant O18 pocket develops at the carbon/helium boundary in a number of
our post-AGB models.
The production of fluorine, neon and phosphorus in the AGB intershell
produces n overabundance at the surface of the merged stars, but generally not
in sufficient quantity. However, the evidence for an AGB origin for these
elements points to progenitor stars with initial masses in the range 1.9 - 3
solar masses.
There is not yet sufficient information to discriminate the origin (fossil or
prompt) of all the abundance anomalies observed in EHe and RCB stars. Further
work is required on argon and s-process elements in the AGB intershell, and on
the predicted yields of all elements from a hot merger.Comment: 20 pages, 8 figures, 3 tables, MNRAS in pres
Association of drusen deposition with choroidal intercapillary pillars in the aging human eye
PURPOSE. To determine the pattern of drusen accumulation with age and to investigate the initial sites of deposition and their relationship to choroidal capillaries in human donor eyes from the eye bank of Moorfields Eye Hospital.METHODS. Wholemounted, hydrated preparations of the choriocapillaris and Bruch's membrane from donor eyes ranging from 42 to 95 years, with or without retinal pigment epithelium (RPE), were examined by conventional and confocal microscopy. Drusen were visualized by their autofluorescence.RESULTS. In all age groups studied autofluorescent drusen were present at the equator but were not found centrally where the vascular architecture is different, being tubular rather than a honeycomb pattern. Autofluorescing drusen were strongly associated with the lateral walls of the choriocapillaris (an area commonly known as the intercapillary pillars of the choriocapillaris (P = 0.028; Wilcoxon signed ranks test). Nonfluorescing drusen were occasionally seen centrally, but were not easily identified, and because of their large size, their localization with respect to capillary walls was not possible.CONCLUSIONS. These results strongly support the notion that autofluorescent drusen are not randomly distributed and have a specific spatial relationship to choroidal vessel walls. That equatorial drusen fluoresce, whereas central drusen do not, suggests that they may have different chemical compositions at the two sites and possibly different significance in age-related macular disease
Optical monitoring of retinal respiration in real time: 670 nm light increases the redox state of mitochondria
Mitochondria play a key role in ageing and disease. Their membrane potentials and ATP production decline with age and this is associated with progressive inflammation, cell loss and death. Here we use broadband Near-Infrared Spectroscopy (NIRS) to non-invasively measure in-vivo changes in aged retinal mitochondrial respiration following exposure to 670 nm, which improves mitochondrial performance and reduces inflammation. Low power NIR light was shone into the eye via a fibre optic and the reflection monitored to measure signature changes in the oxidation of cytochrome c oxidase (COX) in complex IV of the electron transport chain. Changes in retinal haemodynamics and oxygenation were also recorded simultaneously with COX by measuring changes in oxygenated and deoxygenated haemoglobin (Δ[HbO2] and Δ[HHb]). Retinae of aged rats exposed to 670 nm for 5 mins showed consistent progressive increases in oxidation of COX 5 mins post exposure. This remained significantly greater than baseline for up to 2 h. This was not seen when retinae were exposed to 420 nm light of the same power or when no light was applied. 670 nm exposure significantly increased total haemoglobin concentration (Δ[HbT] = Δ[HbO2] +Δ[HHb]) but not haemoglobin difference (Δ[HbDiff] = Δ[HbO2] -Δ[HHb]). There were no changes in blood metrics in association with 420 nm light or when no light exposure was given. Hence, brief 670 nm exposure that is associated with reduced inflammation has a significant positive impact on the redox state of COX in aged retinae. The relative redox state of retinal COX may provide a valuable biomarker in ageing and macular degeneration where declining mitochondrial function is implicated
Tunable Integrated-Optics Nanoscaled Devices Based on Magnetic Photonic Crystals
Magnetooptical properties of magnetic photonic crystals have been
investigated in the view of their possible applications for the modern
integrated-optics devices. A "transfer matrices" formalism was expanded for the
case of oblique light incidence on the periodic nanoscaled magnetic
multilayered systems. Several new effects such as the Faraday effect dependence
on the incidence angle and the tunability of the bandgap defect modes spectral
location by external magnetic fields were found. Several possibilities of
one-dimensional magnetic photonic crystals applications for the optical devices
are discussed. Initial steps towards the practical implementation of the
proposed devices are reported.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Motion Planning for Simple Two-Wheeled Robots
This paper considers various simple ways of navigating in a 2-dimensianal territory with a two-wheeled robot of a type typical in educational robotics. We determine shortest paths under various modes of operation and compare
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