Analysis of top to bottom-kk shuffles

A deck of $n$ cards is shuffled by repeatedly moving the top card to one of the bottom $k_n$ positions uniformly at random. We give upper and lower bounds on the total variation mixing time for this shuffle as $k_n$ ranges from a constant to $n$. We also consider a symmetric variant of this shuffle in which at each step either the top card is randomly inserted into the bottom $k_n$ positions or a random card from the bottom $k_n$ positions is moved to the top. For this reversible shuffle we derive bounds on the $L^2$ mixing time. Finally, we transfer mixing time estimates for the above shuffles to the lazy top to bottom-$k$ walks that move with probability 1/2 at each step.Comment: Published at http://dx.doi.org/10.1214/10505160500000062 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Perceptions and Labor Market Outcomes of Immigrants in Australia after 9/11

I examine whether after the terrorist attacks of September 11, 2001 Muslim immigrants and immigrants who fit the Muslim Arab stereotype in Australia perceive a greater increase in religious and racial intolerance and discrimination compared to other immigrant groups. I also examine whether there is a differential change in their labor market outcomes. I find that after 9/11 there is a greater increase in the likelihood of Muslim men and of those who look like Muslims to report a lot of religious and racial intolerance and discrimination relative to other immigrants. Further, I do not find evidence that after 9/11 Muslims or their stereotypes show a differential change in the likelihood of looking for a new main job or of being employed. There is also no evidence of a differential change in hours worked or in wage incomes. This suggests that the Australian labor market did not react to attitudinal changes in society, at least in the immediate aftermath of 9/11.discrimination, immigrants, September 2001, 9/11

Strategic Alliances in the Global Airline Industry

Strategic alliances are common to any industry. Their presence is felt quite significantly in the airline industry. Starting in the US in 1978 deregulation of airline industry has since brought about sea changes in functioning of the industry. This paper attempts to understand the developments and strategic alliances that have occurred in the airline industry since deregulation. These strategic alliances exist in various forms and differ widely in scope and no consensus on classification was found. The advantages and disadvantages of strategic alliances with respect to the airline industry have been discussed. It is felt that the industry is getting increasingly concentrated. However, no conclusive remarks can be made about consumer welfare.

Design of Small Intramolecular Singlet Fission Chromophore: An Azaborine Candidate and General Small Size Effects

We report the first attempt to design small intramolecular singlet fission chromophores, with the aid of quantum chemistry and explicitly simulating the time evolution of state populations using quantum dynamics method. We start with three previously proposed azaborine-substituted intermolecular singlet fission chromophores. Through analyzing their frontier orbital amplitudes, we select a BN-substituted azulene as the building block. Covalently connecting two such monomers and tuning their relative configuration, we examine three dimers. One dimer is found to be an eminent candidate: the triplet-pair state is quickly formed within 1 ps, and the two triplets are ready to be disentangled. We elucidate the general small size effects in intramolecular singlet fission and focus on specific aspects which should be taken care of when manipulating the fission rate through steric hindrance

Learning theories reveal loss of pancreatic electrical connectivity in diabetes as an adaptive response

Cells of almost all solid tissues are connected with gap junctions which permit the direct transfer of ions and small molecules, integral to regulating coordinated function in the tissue. The pancreatic islets of Langerhans are responsible for secreting the hormone insulin in response to glucose stimulation. Gap junctions are the only electrical contacts between the beta-cells in the tissue of these excitable islets. It is generally believed that they are responsible for synchrony of the membrane voltage oscillations among beta-cells, and thereby pulsatility of insulin secretion. Most attempts to understand connectivity in islets are often interpreted, bottom-up, in terms of measurements of gap junctional conductance. This does not, however explain systematic changes, such as a diminished junctional conductance in type 2 diabetes. We attempt to address this deficit via the model presented here, which is a learning theory of gap junctional adaptation derived with analogy to neural systems. Here, gap junctions are modelled as bonds in a beta-cell network, that are altered according to homeostatic rules of plasticity. Our analysis reveals that it is nearly impossible to view gap junctions as homogeneous across a tissue. A modified view that accommodates heterogeneity of junction strengths in the islet can explain why, for example, a loss of gap junction conductance in diabetes is necessary for an increase in plasma insulin levels following hyperglycemia.Comment: 15 pages, 5 figures. To appear in PLoS One (2013