The desire to extend the Hubble Diagram to higher redshifts than the range of current Type 1a Supernovae observations has prompted investigation into spectral correlations in gamma-ray bursts (GBRs), in the hope that standard candle-like properties can be identified. In this paper, we discuss the potential of these new 'cosmic rulers' and highlight their limitations by investigating the constra...

We measure the length of the baryon acoustic oscillation (BAO) feature, and the expansion rate of the recent Universe, from low-redshift data only, almost model independently. We make only the following minimal assumptions: homogeneity and isotropy, a metric theory of gravity, a smooth expansion history, and the existence of standard candles (supernovæ) and a standard BAO ruler. The rest is det...

One of the obstacles to democratic development is the reluctance of political leaders to leave office. This paper argues that alongside democratic constraints and accountability, leaders’ career concerns — specifically, the possibility of post-tenure careers — is an important factor behind their rotation in office. While literature exists about leaders’ exit and fate, we lack a systematic under...

Many experimental factors and uncontrollable factors may introduce errors in the distance measurement by continuous wave electron paramagnetic resonance. To deal with this problem, several C60 nitroxide diradical adducts with rigid structure and definite molecular dimension were used as distance calibration rulers. Based on the improvement of distance calculation program via adding simulation p...

We examine the impact of political and criminal accountability on economic growth. Governments seek to maximize their own consumption by extracting rents that are costly to growth. When citizens are able to depose politicians through elections, governments are tightly controlled. The rents politicians are able to extract increase in the length of their term. The effect of the threshold of crimi...

Rulers of weakly institutionalized states constantly fear coup attempts. The risk of coups may lead rulers to exclude certain ethnic groups from power—despite creating incentives for excluded groups to rebel against the government. But under what conditions do leaders perceive strong threats? Focusing on post-independence SubSaharan Africa, this paper argues that leaders of countries containing...

old province sogdiana, comprising two major city states- samarkand and bukhara which had  ancient civilization and brilliant cultural heritage, was the most important province  of transoxian. achaemenids, seleucids, kushaniyan, hayateleh, turks and sasanians rule in this region at a time. at the interval between fall of the sassanid (652 a.d) and conquest of transoxiana by muslim (second half o...