The polarized electron beam for the SLAC Linear Collider

The SLAC Linear Collider has been colliding a polarized electron beam with an unpolarized positron beam at the Z^0 resonance for the SLD experiment since 1992. An electron beam polarization of close to 80% has been achieved for the experiment at luminosities up to 8x10^29 cm^-2 s^-1. This is the world's first and only linear collider, and is a successful prototype for the next generation of high energy electron linear colliders. This paper discusses polarized beam operation for the SLC, and includes aspects of the polarized source, spin transport and polarimetry. Presented at the 12th International Symposium on High Energy Spin Physics held at Amsterdam, The Netherlands September 10-14, 1996.Comment: 6 pages, 3 .eps figures, LATE

Electroweak Results from the SLD Experiment

We present an overview of the electroweak physics program of the SLD experiment at the Stanford Linear Accelerator Center (SLAC). A data sample of 550K Z0 decays has been collected. This experiment utilizes a highly polarized electron beam, a small interaction volume, and a very precise pixel vertex detector. We present a preliminary result for the weak mixing angle, sin2(thetaw)=0.23110 +- 0.00029. We also present a preliminary result for the parity violating parameter, A_b = 0.898 +- 0.029. These measurements are used to test for physics beyond the Standard Model.Comment: 9 pages, 7 figure

The Effects of Burst Activity on Soft Gamma Repeater Pulse Properties and Persistent Emission

Soft Gamma Repeaters (SGRs) undergo changes in their pulse properties and persistent emission during episodes of intense burst activity. SGR 1900+14 has undergone large flux increases following recent burst activity. Both SGR 1900+14 and SGR 1806-20 have shown significant changes in their pulse profile and spin-down rates during the last several years. The pulse profile changes are linked with the burst activity whereas the torque variations are not directly correlated with the bursts. Here, we review the observed dynamics of the pulsed and persistent emission of SGR 1900+14 and SGR 1806-20 during burst active episodes and discuss what implications these results have for the burst emission mechanism, the magnetic field dynamics of magnetars, the nature of the torque variability, and SGRs in general.Comment: 9 pages, Woods Hole 2001 GRB and SGR Conferenc

Powerplexer

An electrical power distribution system is described for use in providing different dc voltage levels. A circuit is supplied with DC voltage levels and commutates pulses for timed intervals onto a pair of distribution wires. The circuit is driven by a command generator which places pulses on the wires in a timed sequence. The pair of wires extend to voltage strippers connected to the various loads. The voltage strippers each respond to the pulse dc levels on the pair of wires and form different output voltages communicated to each load

The EEC-Mexican Agreement: Time for Reevaluation?

This Note argues that the EEC and Mexico should modify their current agreement. Part I examines the terms of the EEC-Mexican Agreement. Part II discusses the changing economic factors in the EEC and Mexico that dictate the need for a new agreement. Part III suggests modification of the EEC-Mexican Agreement to enhance the economic relationship between the EEC and Mexico. The Note concludes that the EEC, the second largest trading bloc in the world, should offer Mexico greater cooperation to enable Mexico to expand its non-petroleum exports and thereby modernize its industrial capacity. A new agreement with specific provisions designed to attain these goals would further the economic objectives not only of Mexico, but of the EEC as well

Computing the period of an Ehrhart quasi-polynomial

If P is a rational polytope in R^d, then i_P(t):=#(tP\cap Z^d) is a quasi-polynomial in t, called the Ehrhart quasi-polynomial of P. A period of i_P(t) is D(P), the smallest positive integer D such that D*P has integral vertices. Often, D(P) is the minimum period of i_P(t), but, in several interesting examples, the minimum period is smaller. We prove that, for fixed d, there is a polynomial time algorithm which, given a rational polytope P in R^d and an integer n, decides whether n is a period of i_P(t). In particular, there is a polynomial time algorithm to decide whether i_P(t) is a polynomial. We conjecture that, for fixed d, there is a polynomial time algorithm to compute the minimum period of i_P(t). The tools we use are rational generating functions.Comment: 15 page

Bibliographic Control of Serial Publications

An important problem with serials is bibliographic control. What good does it do for libraries to select, acquire, record, catalog, and bind large holdings of serial publications if the contents of those serials remain a mystery to all except the few who have the opportunity to examine selected journals of continuing personal interest and have discovered some magic way of retaining the gist of the contents? Bibliographic control is the indexing and abstracting of the contents or guts of what is included in the serials. It is this control, provided by secondary publishing services, which this article will discuss. Just as there are problems with serials in general, there are some easily identifiable problems connected with their bibliographic control including: volume, overlap, costs, elements and methods, and a few other miscellaneous considerations. Some history of bibliographic control will also put the current problems in a helpful perspective. Hereafter "bibliographic control" will be designated by the term "abstracting and indexing," one of these alone, or the shorter "a & i." (I do distinguish between abstracting and indexing and believe that they are not in order of importance and difficulty.) Although a & i do provide bibliographic control, this paper will not discuss cataloging, tables of contents, back-of-the-book indexes, year-end indexes, cumulative indexes, lists of advertisers, or bibliographies. If there is to be control, there must always be indexing. Abstracting is a short cut, a convenience, and perhaps a bibliographic luxury which may be now, or is fast becoming, too rich, in light of other factors to be discussed, for library blood and for the users of libraries especially for the users of indexes who may not depend upon the library interface. Abstracting, though, provides a desirable control, and one which will continue to be advocated.published or submitted for publicatio

Reactions of Generation Y to Luxury Hotel Twitter Promotions

Social media refers to the means of interactions among people in which they create, share, and exchange information and ideas in virtual communities and networks (Merriam-Webster, 2013). Social media marketing refers to the process of gaining website traffic or attention through social media sites (Evans, 2008). In today’s society, social media refers mainly to websites including (but not limited to) Facebook, Twitter, LinkedIn, and Google+. The most popular and fastest growing of these social media venues is Twitter. Twitter was founded in 2006 by Jack Dorsey, Evan Williams, and Biz Stone. Since 2006, almost 200 million users across the globe have joined the site; over 140 million tweets are “tweeted” daily (Picard, 2011). Twitter took advantage of a niche in the market, allowing 140 characters to express an idea or emotion. Twitter has changed the media world as a news source, tweeting real-time information from stories that arise (Picard, 2011). In the lodging industry, methods of social media to promote hotels are becoming more popular. Twitter, in particular, has emerged as a “moment of truth” for a hotel, demonstrating how instantly and tactfully hotels react to the thoughts and opinions of former, current, and potential guests. Studies have also suggested that “online social life mirrors offline relationships in many ways” (Moore, p. 440). Therefore, Twitter accounts should be viewed as an extension of the hospitality business, in particular lodging, echoing the relationship a customer would feel upon arrival to the hotel. Hotel marketing teams have reached “great success by driving demand to hotels through increased online advertising and web optimization” (Chipkin, 2013). This has increased overall customer views of the hotel without affecting the rate strategy of the property or brand. Twitter presence could, potentially, help a patron decide between two hotels, “If a promotion, experience or package is unique, it definitely works to generate bookings and helps put you first in a consumer’s mind when they are choosing between two or three hotels,” says Rachel Harrison of Hyatt Andaz (Chipkin, 2013). Hotel companies worldwide are investing in their social media networks. Certain hotels (i.e. W Barcelona) are even hiring social media and marketing managers whose responsibilities include instant Twitter feedback (Appendix 1). The purpose behind this investment is to maximize these social media accounts, creating feedback from all potential guests, allowing them to react to both positive and negative word of mouth. Social media managers have recently encountered an opportunity; Generation Y is becoming a target demographic. As Generation Y enters the workforce and begins a career, the exposure to hotel brands and types will increase. Luxury hotel stays are becoming more financially reachable to these Generation Y guests because of their career advancements (Fields, 2013). This study will serve to evaluate the added benefits from the adoption of social media channels, particularly Twitter