Generating perfect fluid spheres in general relativity

Ever since Karl Schwarzschild's 1916 discovery of the spacetime geometry describing the interior of a particular idealized general relativistic star -- a static spherically symmetric blob of fluid with position-independent density -- the general relativity community has continued to devote considerable time and energy to understanding the general-relativistic static perfect fluid sphere. Over the last 90 years a tangle of specific perfect fluid spheres has been discovered, with most of these specific examples seemingly independent from each other. To bring some order to this collection, in this article we develop several new transformation theorems that map perfect fluid spheres into perfect fluid spheres. These transformation theorems sometimes lead to unexpected connections between previously known perfect fluid spheres, sometimes lead to new previously unknown perfect fluid spheres, and in general can be used to develop a systematic way of classifying the set of all perfect fluid spheres.Comment: 18 pages, 4 tables, 4 figure

“BECAUSE WE HAVE CHOSEN A LIFE OF PEACE”: A QUANTITATIVE AND QUALITATIVE STUDY OF VEGAN FOOD NARRATIVES

Restaurants, grocery stores, fast food chains, and companies all over the United States introduce the consumer to more vegan products, dishes, and services than ever before. The rise of veganism therefore offers a rhetorical platform that should be studied. This dissertation discusses the rhetoric of veganism by analyzing food narratives of vegans through a critical intersectional lens and consists of three research stages. The first research stage investigates the narratology of Glenn Scott Lacey’s documentary, Vegan: Everyday Stories(2016). In particular, this rhetorical analysis focuses on the evaluative belief system of vegan storytelling by applying narrative and ideological criticism. The second research stage considers quantitative data collected from an online survey that combined questions on food and attitudes about social justice engagement. The results of a path analysis illustrate the multi-layered nature of veganism and what motivates vegans to challenge their food habits. The third and last research stage shares qualitative data derived from Skype interviews conducted with vegans who took the previously mentioned survey. These interviews offer qualitative data that illustrate how the shared value of knowledge/education plays a vital role in becoming vegan, and how an intersectional lens can, when employed critically, enrich veganism as a social justice movement through a storied activism. Finally, the project comments on how the studying of food narratives can refine the vegan movement since storied activism can lead to a better understanding of overlapping oppressions

Integrirano planiranje opskrbe električnom energijom, plinom i toplinskom energijom u općini

This paper presents the results of a case study to investigate different alternatives for the energy supply to a municipality on the western coast of Norway. The following alternatives for energy supply are modelled and analysed: i) a district heating system with three different heat centrals, ii) a natural gas distribution system and iii) a low temperature distribution system. The case study is performed with the optimization model "eTransport" developed for the planning of local energy systems where several alternative energy carriers and technologies are considered simultaneously. The model minimizes the total energy system cost of meeting the demands of electricity, heating, cooling and gas within a geographical area over a given planning horizon. The model uses a detailed network representation of infrastructures to consider investments in distributed central stations, components, cables and pipelines. The object function includes investments, operating and environmental costs.Ovaj članak prezentira rezultate analize slučaja koja istražuje razne alternative za opskrbu energije jedne općine na zapadnoj obali Norveške. Sljedeće alternative za opskrbu energije su modelirane i analizirane: i) Područno grijanje s tri različite toplane ii) Distribucijski sustav za prirodni plin iii) Niskotemperaturni distribucijski sustav. Analiza slučaja je napravljena pomoću optimizacijskog modela „eTransport“ razvijenog za planiranje lokalnih energetskih sustava s primjenom raznih nosioca energije i tehnologija. Model minimizira cijenu sustava koji zadovoljava potrebu za električnom i toplinskom energijom, hlađenjem i plinom u nekom geografskom području za vrijeme planiranja. Model koristi detaljnu reprezentaciju mrežne infrastrukture da uzme u obzir investiciju u toplane, komponente, troškove okoliša i operativne troškove

Aufbau und Steuerung von Dienstleistungsmarken : die Markenpersönlichkeit als Differenzierungspotenzial und Ausgangspunkt einer Vertrauensbeziehung zwischen Dienstleistungsmarke und Kunde

Mit zunehmender Bedeutung starker Marken für die Wettbewerbsfähigkeit und den Markterfolg von Dienstleistungsunternehmen widmet sich auch die Marketing-Forschung verstärkt dem Aufbau und der Wirkung von Dienstleistungsmarken. Aufgrund der inhärenten Merkmale von Dienstleistungen können starke Marken Vertrauen generieren und bieten darüber hinaus ein Differenzierungspotenzial mittels intangibler, symbolischer Attribute. Bislang existieren in diesem Forschungsbereich vor allem konzeptionelle Arbeiten sowie einige qualitative Studien, in denen Dienstleistungsmarken aus der Perspektive von Managern untersucht werden. Demgegenüber finden sich nur wenige quantitative empirische Forschungsbeiträge, die sich mit der kundenseitigen Wirkung von Dienstleistungsmarken befassen. Ziel der vorliegenden Studie ist es daher, den Einfluss verschiedener Marketing Instrumente auf die Markenpersönlichkeit als Differenzierungspotenzial und Ausgangspunkt einer Vertrauensbeziehung zwischen Dienstleistungsmarke und Kunde zu untersuchen. Zu diesem Zweck wurden Urlaubs- und Geschäftsreisende zur Wahrnehmung von internationalen Fluglinien befragt. Mittels Strukturgleichungsmodell werden die hypothetischen Wirkungszusammenhänge zwischen Marketingvariablen wie Mitarbeiterqualität, Dienstleistungsqualität, Printwerbung und Country-of-Origin-Image mit einzelnen Markenpersönlichkeitsdimensionen, dem Vertrauen in die Marke und der Einstellung gegenüber der Marke überprüft. Dabei zeigt sich, dass Vertrauen in eine Dienstleistungsmarke durch drei Markenpersönlichkeitsdimensionen (Verlässlichkeit, Natürlichkeit und Temperament) erzeugt wird, während die Dimension Attraktivität lediglich zur Differenzierung der Markenpersönlichkeit beitragen kann. Die vorliegende Studie liefert zudem empirische Bestätigung für viele Thesen bestehender Forschungsarbeiten. So wird einerseits belegt, dass Mitarbeiter eine Schlüsselrolle beim Aufbau von Dienstleistungsmarken übernehmen. Eine anschließende Varianzanalyse beweist, dass persönliche Erfahrungen mit dem Dienstleistungsanbieter tatsächlich effektiver für das Markenmanagement sind, als Mundpropaganda oder werbliche Kommunikation

Expression in Escherichia coli of a cloned DNA sequence encoding the pre-S2 region of hepatitis B virus

A DNA sequence encoding the entire pre-S2 region (amino acids 120-174; serotype ayw) of human hepatitis B virus envelope protein has been inserted into the lacZ gene of the plasmid pSKS105 yielding a recombinant, pWS3. Lac+ colonies of the Escherichia coli M182 (lacIOPZYA), isolated after transformation with pWS3, produced a pre-S2 peptide-ß-galactosidase fusion protein. This fusion protein, which comprised as much as 3% of the total bacterial protein, was purified to >90% homogeneity by affinity chromatography on p-aminophenyl-ß-D-thiogalactoside-Sepharose. It is immunoprecipitable with rabbit antibodies to a synthetic peptide corresponding to amino acids 120-145 of the pre-S2 region of serotype adw [pre-S(120-145)] or with antibodies to hepatitis B virus. pre-S(120-145) completely blocked the binding of either antibody to the pre-S2 peptide-ß-galactosidase fusion protein. These results indicate that there are antigenic determinants on the fusion protein that are closely related to, if not identical to, determinants on synthetic pre-S(120-145) and on pre-S2 sequences of native hepatitis B virus particles. Thus, bacteria transformed with pWS3 can provide an abundant source of pre-S2-ß-galactosidase fusion protein, which may prove useful either as a diagnostic reagent possessing marker enzyme activity suitable for ELISA tests or as an immunogen with potential to contribute to active prophylaxis of hepatitis B

Solution generating theorems for perfect fluid spheres

The first static spherically symmetric perfect fluid solution with constant density was found by Schwarzschild in 1918. Generically, perfect fluid spheres are interesting because they are first approximations to any attempt at building a realistic model for a general relativistic star. Over the past 90 years a confusing tangle of specific perfect fluid spheres has been discovered, with most of these examples seemingly independent from each other. To bring some order to this collection, we develop several new transformation theorems that map perfect fluid spheres into perfect fluid spheres. These transformation theorems sometimes lead to unexpected connections between previously known perfect fluid spheres, sometimes lead to new previously unknown perfect fluid spheres, and in general can be used to develop a systematic way of classifying the set of all perfect fluid spheres. In addition, we develop new ``solution generating'' theorems for the TOV, whereby any given solution can be ``deformed'' to a new solution. Because these TOV-based theorems work directly in terms of the pressure profile and density profile it is relatively easy to impose regularity conditions at the centre of the fluid sphere.Comment: 8 pages, no figures, to appear in the proceedings of the NEB XII Conference (Recent Developments in Gravity), 29 June - 2 July, 2006, Napflio, Greec