Production of Beryllium and Boron by Spallation in Supernova Ejecta

The abundances of beryllium and boron have been measured in halo stars of metallicities as low as [Fe/H] =-3. The observations show that the ratios Be/Fe and B/Fe are independent of metallicity and approximately equal to their solar values over the entire range of observed metallicity. These observations are in contradiction with the predictions of simple models of beryllium and boron production by spallation in the interstellar medium of a well mixed galaxy. We propose that beryllium and boron are produced by spallation in the ejecta of type II supernovae. In our picture, protons and alpha particles are accelerated early in the supernova event and irradiate the heavy elements in the ejecta long before the ejecta mixes with the interstellar medium. We follow the propagation of the accelerated particles with a Monte-Carlo code and find that the energy per spallation reaction is about 5 GeV for a variety of initial particle spectra and ejecta compositions. Reproducing the observed Be/Fe and B/Fe ratios requires roughly 3 times 10^{47} ergs of accelerated protons and alphas. This is much less than the 10^{51} ergs available in a supernova explosion.Comment: 5 pages, Latex, to be published in the 4th Compton Symposium Conference Proceedin

A systematic review of neuroprotective strategies after cardiac arrest: from bench to bedside (Part I - Protection via specific pathways).

Neurocognitive deficits are a major source of morbidity in survivors of cardiac arrest. Treatment options that could be implemented either during cardiopulmonary resuscitation or after return of spontaneous circulation to improve these neurological deficits are limited. We conducted a literature review of treatment protocols designed to evaluate neurologic outcome and survival following cardiac arrest with associated global cerebral ischemia. The search was limited to investigational therapies that were utilized to treat global cerebral ischemia associated with cardiac arrest. In this review we discuss potential mechanisms of neurologic protection following cardiac arrest including actions of several medical gases such as xenon, argon, and nitric oxide. The 3 included mechanisms are: 1. Modulation of neuronal cell death; 2. Alteration of oxygen free radicals; and 3. Improving cerebral hemodynamics. Only a few approaches have been evaluated in limited fashion in cardiac arrest patients and results show inconclusive neuroprotective effects. Future research focusing on combined neuroprotective strategies that target multiple pathways are compelling in the setting of global brain ischemia resulting from cardiac arrest

A Theoretical Analysis of Thermal Radiation from Neutron Stars

As soon as it was realized that the direct URCA process is allowed by many modern nuclear equation of state, an analysis of its effect on the cooling of neutron stars was undertaken. A primary study showed that the occurrence of the direct URCA process makes the surface temperature of a neutron star suddenly drop by almost an order of magnitude when the cold wave from the core reaches the surface when the star is a few years old. The results of this study are published in Page and Applegate. As a work in progress, we are presently extending the above work. Improved expressions for the effect of nucleon pairing on the neutrino emissivity and specific heat are now available, and we have incorporated them in a recalculation of rate of the direct URCA process

Carryless Arithmetic Mod 10

We investigate what arithmetic would look like if carry digits into other digit position were ignored, so that 9 + 4 = 3, 5 + 5 = 0, 9 X 4 = 6, 5 X 4 = 0, and so on. For example, the primes are now 21, 23, 25, 27, 29, 41, 43, 45, 47, ... .Comment: 7 pages. To the memory of Martin Gardner (October 21, 1914 -- May 22, 2010). Revised version (with a number of small improvements), July 7 201

Teacher Attrition in Charter Schools

This study focuses on the reasons why teachers are leaving charter schools. It is based on analyses of data collected in surveys of charter school employees from around the country from 1997-2006. The authors found that while overall attrition rates fluctuate from year to year and state to state, as many as one in four charter school teachers leave each year- approximately double the traditional public school rate of 11 percent. Moreover, attrition among new teachers in charter schools is close to 40 percent annually. The authors contend that high attrition, "consumes resources of schools, impedes schools' efforts to build professional learning communities and positive, stable school cultures," and recommend that supporters of charters schools focus efforts on reducing teacher attrition

ALTA OR NLTA: WHAT'S IN THE NAME? LAND TENURE DILEMMA AND THE FIJI SUGAR INDUSTRY

Since 1997, the agricultural leases on Native land, issued under the 1976 Agricultural and Landlord Tenants Act (ALTA), began to expire. The sugar industry is the main commodity export earner for Fiji, directly contributing about 22% of the national GDP and supporting over 25% of the country's active labor force. Fiji exports 80% of its sugar production, earning on average of $250-300 million in foreign exchange annually. Several options have been suggested, including: non-renewal of leases, with the land reverting to Fijian owners; renewal of ALTA but with land rents pegged to the gross value of production instead of the unimproved capital value; sharecropping and contract wage arrangements; and abolishment of lease arrangement under ALTA with leases to be issued under an institutional arrangement guided by the Native Lands Trust Act (NLTA). The land tenure system adopted will have a significant impact not only on the efficiency of the sugar cane sector but also on Fiji's ability to meet its international obligations of sugar exports. This paper explores the land tenure dilemma facing Fiji today. It assesses the economic implications of the various forms of land lease system proposed. This analysis is carried out in terms of efficiency, equity, and risk sharing in the current preferential market access environment and under possible future world market conditions. Suggestions are made on institutional arrangements that could enhance efficiency in resource use and encourage sharing of production risks that arise due to variability in factor prices and climatic conditions as well as sugar prices.Land tenure -- Government policy -- Fiji, Landlord and tenant -- Law and legislation -- Fiji, Land tenure -- Economic aspects -- Fiji, Agricultural laws and legislation -- Fiji, Leases -- Fiji, Sugar trade -- Fiji, Sugarcane industry -- Economic aspects -- Fiji, Fiji. Agricultural and Landlord Tenants Act (1976), Crop Production/Industries, Land Economics/Use,

Whose Decline? Which Academic Libraries are “Deserted” in Terms of Reference Transactions?

Permission for inclusion in IUPUI ScholarWorks granted by Reference and User Services Association (RUSA), June 2010. Further reproduction prohibited without permission. [BREAK] Publisher: American Library Association [BREAK] This item submitted to IUPUI ScholarWorks as part of the OASIS Project.This study examines reference transaction quantities reported through the Academic Library Survey of the National Center for Educational Statistics to explore whether, and the extent to which, academic libraries are seeing a decline: the beginnings of a "deserted library." Data from 2002 and 2004 shows a decline in reference transactions per week on a per-library basis and on a per-student basis, but this decline differs by the type of institution (Carnegie Class). Librarians at master's institutions have actually seen an increase in the numbers of questions per librarian. ARL institutions' patterns differ from those of other universities, which calls into question using ARL experiences as indicative of the wider academic universe

On Asymmetric Coverings and Covering Numbers

An asymmetric covering D(n,R) is a collection of special subsets S of an n-set such that every subset T of the n-set is contained in at least one special S with |S| - |T| <= R. In this paper we compute the smallest size of any D(n,1) for n <= 8. We also investigate ``continuous'' and ``banded'' versions of the problem. The latter involves the classical covering numbers C(n,k,k-1), and we determine the following new values: C(10,5,4) = 51, C(11,7,6,) =84, C(12,8,7) = 126, C(13,9,8)= 185 and C(14,10,9) = 259. We also find the number of nonisomorphic minimal covering designs in several cases.Comment: 11 page