20 research outputs found
In Search of Possible Associations between Planetary Nebulae and Open Clusters
We consider the possibility of cluster membership for 13 planetary nebulae
that are located in close proximity to open clusters lying in their lines of
sight. The short lifetimes and low sample size of intermediate-mass planetary
nebulae with respect to nearby open clusters conspire to reduce the probability
of observing a true association. Not surprisingly, line of sight coincidences
almost certainly exist for 7 of the 13 cases considered. Additional studies are
advocated, however, for 6 planetary nebula/open cluster coincidences in which a
physical association is not excluded by the available evidence, namely M
1-80/Berkeley 57, NGC 2438/NGC 2437, NGC 2452/NGC 2453, VBRC 2 & NGC 2899/IC
2488, and HeFa 1/NGC 6067. A number of additional potential associations
between planetary nebulae and open clusters is tabulated for reference
purposes. It is noteworthy that the strongest cases involve planetary nebulae
lying in cluster coronae, a feature also found for short-period cluster
Cepheids, which are themselves potential progenitors of planetary nebulae.Comment: Accepted for publication in PASP (December 2007
Inequality, Fiscal Capacity and the Political Regime: Lessons from the Post-Communist Transition
Using panel data for twenty-seven post-communist economies between 1987-2003, we examine the nexus of relationships between inequality, fiscal capacity (defined as the ability to raise taxes efficiently) and the political regime. Investigating the impact of political reform we find that full political freedom is associated with lower levels of income inequality. Under more oligarchic (authoritarian) regimes, the level of inequality is conditioned by the stateâs fiscal capacity. Specifically, oligarchic regimes with more developed fiscal systems are able to defend the prevailing vested interests at a lower cost in terms of social injustice. This empirical finding is consistent with the model developed by Acemoglu (2006). We also find that transition countries undertaking early macroeconomic stabilisation now enjoy lower levels of inequality; we confirm that education fosters equality and the suggestion of Commander et al (1999) that larger countries are prone to higher levels of inequality.http://deepblue.lib.umich.edu/bitstream/2027.42/57211/1/wp831 .pd
The catalogue of structural and dynamical characteristics of 103 open star clusters and the firstresults of its investigation
Sodium Benzoate, a Metabolite of Cinnamon and a Food Additive, Upregulates Ciliary Neurotrophic Factor in Astrocytes and Oligodendrocytes
MS and excitotoxicity
In this section, it will be studied how excitotoxicity contributes to neurodegeneration in the context of multiple sclerosis (MS). MS has long been regarded as an autoimmune inflammatory disease targeting oligodendrocytes of the central nervous system (CNS). However, recent advancement in research questioned whether MS is merely an inflammatory disease despite pathological evidences of degeneration are clearly present. More recent findings further challenge the research focus of MS which previously thought oligodendrocytes as the main target, whereas current debate points towards pathology of MS being primarily dysfunctional glial interaction, i.e., astrocytes and microglia. Herein, a brief overview will be provided on how various aspects of excitotoxicity are evident in MS pathology and its possible roles between interactions of cells in the CNS that ultimately lead to neurodegeneration in inflammatory condition of MS.9 page(s