Hydrogen 2p--2s transition: signals from the epochs of recombination and reionization

We propose a method to study the epoch of reionization based on the possible observation of 2p--2s fine structure lines from the neutral hydrogen outside the cosmological H {\sc ii} regions enveloping QSOs and other ionizing sources in the reionization era. We show that for parameters typical of luminous sources observed at $z \simeq 6.3$ the strength of this signal, which is proportional to the H {\sc i} fraction, has a brightness temperature $\simeq 20 \mu K$ for a fully neutral medium. The fine structure line from this redshift is observable at $\nu \simeq 1 \rm GHz$ and we discuss prospects for the detection with several operational and future radio telescopes. We also compute the characteristics of this signal from the epoch of recombination: the peak brightness is expected to be $\simeq 100 \mu K$; this signal appears in the frequency range 5-10 MHz. The signal from the recombination era is nearly impossible to detect owing to the extreme brightness of the Galactic emission at these frequencies.Comment: 17 pages, 1 figure, to appear in Ap

Inside Money, Procyclical Leverage, and Banking Catastrophes

We explore a model of the interaction between banks and outside investors in which the ability of banks to issue inside money (short-term liabilities believed to be convertible into currency at par) can generate a collapse in asset prices and widespread bank insolvency. The banks and investors share a common belief about the future value of certain long-term assets, but they have different objective functions; changes to this common belief result in portfolio adjustments and trade. Positive belief shocks induce banks to buy risky assets from investors, and the banks finance those purchases by issuing new short-term liabilities. Negative belief shocks induce banks to sell assets in order to reduce their chance of insolvency to a tolerably low level, and they supply more assets at lower prices, which can result in multiple market-clearing prices. A sufficiently severe negative shock causes the set of equilibrium prices to contract (in a manner given by a cusp catastrophe), causing prices to plummet discontinuously and banks to become insolvent. Successive positive and negative shocks of equal magnitude do not cancel; rather, a banking catastrophe can occur even if beliefs simply return to their initial state. Capital requirements can prevent crises by curtailing the expansion of balance sheets when beliefs become more optimistic, but they can also force larger price declines. Emergency asset price supports can be understood as attempts by a central bank to coordinate expectations on an equilibrium with solvency.Comment: 31 pages, 10 figure

Arranged Marriages: An Inappropriate Fabrication

This paper explores what an inappropriate relationship is and the taxonomy scale used to evaluate different relationships, specifically, arranged marriages. Arranged marriage is a topic that is considered taboo depending on global location. It is more prevalent in Eastern nations such as India, China, Oriental countries, and the Middle East. However, Western influence plays a significant role on what is and is not acceptable, as societal norms differ from place to place. What is defined as normal by culture is what helps to define if a relationship is or is not viewed as inappropriate. This paper is designed to explore arranged marriages and determine, based upon a preexisting classification system, whether they are appropriate or inappropriate. When analyzed as a whole, arranged marriages do not seem to fit the categories or aspects that make a relationship inappropriate

Progress in preventing injuries: from international collaboration to local implementation

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Costs associated with road crashes in the WHO European Region

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Hydroboration of cyclic allenes with disiamylborane

It has been shown that 1,2-cyclononadiene and 1,2-cyclotridecadiene undergo 78 and 100% hydroboration respectively, with disiamylborane. 1,2-Cyclononadiene gave products which represented 83% attack of boron at the central carbon atom and 17% attack at the terminal carbon atom. 1,2-Cyclotridecadiene gave 62% central carbon attack and 38% terminal carbon attack. The reactivity and selectivity may be explained mainly in terms of steric effects on a four-centered transition state