Regulation of Returns to Transportation Agencies

An experiment on Cosmic rays performed by Carl D Anderson led to the accidental discovery of the positron in 1932. The discovery was a turning point in particle physics which led to numerous other theories and has been discussed by scientists all over the world. Anderson had photographed a 63 MeV, upward moving electron. The possible origin of such a positron has never before been discussed and is what this report will aim to explain. The report will include some evidence that the particle is in fact a positron as well as a discussion of the four main theories whose possibility and probability will be discussed; pion decay, muon decay, magnetic field bending and pair production. The report will also cover a historical background for Anderson’s experiment, as well as a theoretical background needed for the theories of the origin. The probability of discovering a positron with any of the theorized origins is extremely low and for some theories, even impossible.  År 1932 upptäckte Carl D. Anderson positronen under ett experiment utformat för att undersöka kosmisk strålning. Det var en vändpunkt inom partikelfysiken och har lagt grunden för många nya teorier och diskuterats av forskare över hela världen. Anderson hade fotograferat en 63 MeV positron som rörde sig uppåt. Ursprunget hos en sådan positron har aldrig blivit diskuterat och är vad denna rapport menar att förklara. Rapporten kommer innehålla bevis för att den fotograferade partikeln faktiskt är en positron men även de fyra teorier till uppkomsten av positronen vars möjlighet och sannolikhet kommer att diskuteras. Dessa teorier är; pionsönderfall, myonsönderfall, böjning i magnetfält och parproduktion. Rapporten kommer också att inkludera en historisk bakgrund till Andersons experiment men också en teoretisk bakgrund som grund till de olika teorier som kommer att diskuteras. Sannolikheten att upptäcka en positron med ursprung från de teorier vi diskuterat är extremt liten och för vissa teorier även omöjligt

Evaluating Conservation Effectiveness and Adaptation in Dynamic Landscapes

Rissman talks about evaluating conservation easement effectiveness requires interdisciplinary research that reaches beyond legal analysis to examine how easements influence human behaviors, which subsequently influence environmental conditions. Conservation easement effectiveness is not a fixed target, but is influenced over time by social and ecological landscape change. The promise of perpetuity is central to the appeal of conservation easements within the conservation movement

High Pressure X-ray Diffraction Study of MgMn2O4 Tetragonal Spinel

The phase stability of the MgMn2O4 spinel has been studied by means of high-pressure X-ray diffraction for pressures up to 30 GPa. Two samples with different inversion degrees have been considered. Both spinels undergo a phase transition towards an orthorhombic structure (CaMn2O4-type). For the more inverted sample the transition pressure is at least 1 GPa lower with respect to that of the less inverted spinel. Also the volume contraction, relative compressibility and density trends are different for the two samples. These variations have been explained according to differences in the cation distribution. and electronic properties of the samples.Comment: 12 pages; 4 Figures presented at the SRMS-

Spin Susceptibility and Superexchange Interaction in the Antiferromagnet CuO

Evidence for the quasi one-dimensional (1D) antiferromagnetism of CuO is presented in a framework of Heisenberg model. We have obtained an experimental absolute value of the paramagnetic spin susceptibility of CuO by subtracting the orbital susceptibility separately from the total susceptibility through the $^{63}$Cu NMR shift measurement, and compared directly with the theoretical predictions. The result is best described by a 1D $S=1/2$ antiferromagnetic Heisenberg (AFH) model, supporting the speculation invoked by earlier authors. We also present a semi-quantitative reason why CuO, seemingly of 3D structure, is unexpectedly a quasi 1D antiferromagnet.Comment: 7 pages including 4 tables and 9 figure

ARPES: A probe of electronic correlations

Angle-resolved photoemission spectroscopy (ARPES) is one of the most direct methods of studying the electronic structure of solids. By measuring the kinetic energy and angular distribution of the electrons photoemitted from a sample illuminated with sufficiently high-energy radiation, one can gain information on both the energy and momentum of the electrons propagating inside a material. This is of vital importance in elucidating the connection between electronic, magnetic, and chemical structure of solids, in particular for those complex systems which cannot be appropriately described within the independent-particle picture. Among the various classes of complex systems, of great interest are the transition metal oxides, which have been at the center stage in condensed matter physics for the last four decades. Following a general introduction to the topic, we will lay the theoretical basis needed to understand the pivotal role of ARPES in the study of such systems. After a brief overview on the state-of-the-art capabilities of the technique, we will review some of the most interesting and relevant case studies of the novel physics revealed by ARPES in 3d-, 4d- and 5d-based oxides.Comment: Chapter to appear in "Strongly Correlated Systems: Experimental Techniques", edited by A. Avella and F. Mancini, Springer Series in Solid-State Sciences (2013). A high-resolution version can be found at: http://www.phas.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Reviews/ARPES_Springer.pdf. arXiv admin note: text overlap with arXiv:cond-mat/0307085, arXiv:cond-mat/020850

Morphological effects on IR band profiles: Experimental spectroscopic analysis with application to observed spectra of oxygen-rich AGB stars

To trace the source of the unique 13, 19.5, and 28 $\mu$m emission features in the spectra of oxygen-rich circumstellar shells around AGB stars, we have compared dust extinction spectra obtained by aerosol measurements. We have measured the extinction spectra for 19 oxide powder samples of eight different types, such as Ti-compounds (TiO, TiO$_2$, Ti$_2$O$_3$, Ti$_3$O$_5$, Al$_2$TiO$_5$, CaTiO$_3$), $\alpha$-, $\gamma$-, $\chi$-$\delta$-$\kappa$-Al$_2$O$_3$, and MgAl$_2$O$_4$ in the infrared region (10 - 50 $\mu$m) paying special attention to the morphological (size, shape, and agglomeration) effects and the differences in crystal structure. Anatase (TiO$_2$) particles with rounded edges are the possible 13, 19.5 and 28 $\mu$m band carriers as the main contributor in the spectra of AGB stars, and spherically shaped nano-sized spinel and Al$_2$TiO$_5$ dust grains are possibly associated with the anatase, enhancing the prominence of the 13 $\mu$m feature and providing additional features at 28 $\mu$m. The extinction data sets obtained by the aerosol and CsI pellet measurements have been made available for public use at http://elbe.astro.uni-jena.deComment: 17 pages, 8 figures, Accepted 24 March 2009 for publication in A&

Стартовое устройство геохода. Требования к конструкции, результаты испытаний

В статье сформулированы требования к стартовому устройству геохода. Приведены некоторые результаты испытаний