Searching for Signals of Dark Matter Decay

Dark matter is believed to make up approximately eighty-three percent of the matter in the universe. Despite its apparent abundance, it has not yet been directly detected, and it is not known what types of particles it is composed of. Efforts to understand what dark matter is made of and how it fits into the Standard Model of particle physics is currently an important and active area of research. In this paper we investigate a method of studying dark matter indirectly by using terrestrial neutrino telescopes to search for signs of dark matter decay. In particular, we study leptonically decaying dark matter and apply the results to models of spin-1/2, charge-asymmetric dark matter whose parameters have been fitted to describe the observed electron-positron flux seen at the PAMELA, H.E.S.S., and Fermi-LAT experiments

The Column Strength of Two Extruded Aluminum-Alloy H-Sections

Extruded aluminum-alloy members of various cross sections are used in aircraft as compression members either singly or as stiffeners for aluminum-alloy sheet. In order to design such members, it is necessary to know their column strength or, in the case of stiffeners, the value of the double modulus, which is best obtained for practical purposes from column tests. Column tests made on two extruded h-sections are described, and column formulas and formulas for the ratio of the double modulus to Young's modulus, based on the tests, are given

The Economic Incidence of the Interstate Commerce Act of 1887: A Theoretical and Empirical Analysis of the Short-haul Pricing Constraint

The public and private interest hypotheses permeate contemporary regulatory analyses. Both theories are used to explain the inception of the first major federal regulatory agency, the Interstate Commerce Commission (ICC). According to the public and private interest hypotheses, the regulations promulgated by the ICC benefited either railroads or shippers. This paper presents an alternative view consistent with the multiple interest theory of regulation. It is demonstrated that the major regulatory instrument of the ICC, the short-haul pricing constraint (SHPC), altered the equilibria of railroad markets in a way which benefitted the class of shippers (short-haul shippers) facing monopolistic railroad markets. The SHPC also benefitted some railroads by increasing the correspondence between unregulated, cooperative and regulated, noncooperative levels of long-haul shipments. The proposition that the ICC benefited short-haul shippers and railroads is supported by an empirical analysis of the effects of the inception of federal regulation and implementation of the SHPC on stock prices. The results of the paper indicate that the public and private interest interpretations of the ICC are neither contradictory nor complete, but instead are complementary. A theoretical and empirical analysis of the chief regulatory mechanism of the ICC provides this synthesis

Regulation and the Theory of Legislative Choice: The Interstate Commerce Act of 1887

This article concerns the economic incidence of the Interstate Commerce Act of 1887 (ICA). Our focus is the short-haul pricing constraint, a provision of the ICA that prohibited railroads from charging higher rates to isolated, primarily agrarian shippers than it charged to intercity shippers of similar commodities. Utilizing the event study methodology, we find that the impending passage of the ICA generated a distribution of abnormal returns to railroads and shipping firms that is consistent with the theoretical implications of our analysis of the short- haul pricing constraint (SHPC). However, early interpretations of the SHPC by the Interstate Commerce Commission reduced some of the abnormal returns to railroads in a manner that is inconsistent with the hypothesis that the short-haul pricing constraint was an important mechanism of early railroad regulation. The analysis does support a multiple-interest interpretation of the Interstate Commerce Act and has implications for the positive theory of regulation

Regulation and the theory of legislative choice: The Interstate Commerce Act of 1887

The economic effects of federal regulation cannot be explained from congressional institutions. Two factors determine the specific pattern. The first is how interests are represented in the Congress, especially in the relevant committees. Committees matter because their members can veto proposals made by others. The second factor is bicameralism. The need to build majority support in two chambers matters when interest groups are not distributed identically across both houses. Specific interests win in the legislative process because of their representation within the political institutions. We examine the first major regulatory agency, the Interstate Commerce Commission (ICC), founded in 1887. The inception of the ICC was not solely a cartel mechanism for the railroads (as the pure capture view asserts) nor solely a mechanism to correct market abuses by the railroads (as the public interest theory maintains). The ICC provided an benefits, some to railroads and some to nonrailroad interests, notably shorthaul shippers

Reversible Intercalation of Fluoride-Anion Receptor Complexes in Graphite

We have demonstrated a route to reversibly intercalate fluoride-anion receptor complexes in graphite via a nonaqueous electrochemical process. This approach may find application for a rechargeable lithium–fluoride dual-ion intercalating battery with high specific energy. The cell chemistry presented here uses graphite cathodes with LiF dissolved in a nonaqueous solvent through the aid of anion receptors. Cells have been demonstrated with reversible cathode specific capacity of approximately 80 mAh/g at discharge plateaus of upward of 4.8 V, with graphite staging of the intercalant observed via in situ synchrotron X-ray diffraction during charging. Electrochemical impedance spectroscopy and 11B nuclear magnetic resonance studies suggest that co-intercalation of the anion receptor with the fluoride occurs during charging, which likely limits the cathode specific capacity. The anion receptor type dictates the extent of graphite fluorination, and must be further optimized to realize high theoretical fluorination levels. To find these optimal anion receptors, we have designed an ab initio calculations-based scheme aimed at identifying receptors with favorable fluoride binding and release properties

Toward precision Fermi liquid theory in flatland

The ultra-cold and weakly-coupled Fermi gas in two spatial dimensions is studied in an effective field theory framework. Universal corrections to the energy density are computed to three orders in the interaction strength with special consideration given to the scale ambiguity associated with the non-trivial renormalization of the singular contact interactions. The isotropic superfluid gap is obtained to next-to-leading order, and nonuniversal contributions to the energy density due to effective range effects, p-wave interactions and three-body forces are computed. Results are compared with precise Monte Carlo simulations of the energy density and the contact in the weakly-coupled attractive and repulsive Fermi liquid regimes. In addition, the known all-orders sum of ladder and ring diagrams is compared with Monte Carlo simulations at weak coupling and beyond.Comment: 34 pages, 17 figure