Spontaneous Breaking of Classical PT Symmetry

The classical trajectories of the family of complex PT-symmetric Hamiltonians $H=p^2+x^2(ix)^\epsilon$ ($\epsilon\geq0$) form closed orbits. All such complex orbits that have been studied in the past are PT symmetric (left-right symmetric). The periods of these orbits exhibit an unusual dependence on the parameter $\epsilon$. There are regions in $\epsilon$ of smooth behavior interspersed with regions of rapid variation. It is demonstrated that the onset of rapid variation is associated with strange new kinds of classical trajectories that have never been seen previously. These rare kinds of trajectories are not PT symmetric and occur only for special rational values of $\epsilon$.Comment: 16 pages, 17 figures, accepted for publication in the Journal of Mathematical Physic

The Farmer-Labor Party In Minnesota Politics: 1918-1948

This dissertation is an examination of the Farmer-Labor Party in Minnesota politics between 1918 and 1948. This movement represented an exceptional chapter in Minnesota history, since the Farmer-Labor Party was the only sustained successful third party movement in the state. This study focuses on the origins of the movement and the reasons for its emergence, its main figures, the goals of the party, its continued electoral success from 1922 through 1936, its decline beginning in 1938, its merger with the Democratic Party of Minnesota in 1944, and finally the subsequent battle for control of this newly-merged DFL (Democratic Farmer-Labor) Party between Democrats led by Hubert H. Humphrey and the former Farmer-Laborites between 1946 and 1948. The study uses an extensive collection of primary and secondary sources relating to the Minnesota Farmer-Labor Party and other issues and political events within the timeframe in question. The conclusions of the investigation include the claim that the movement emerged chiefly because there was no viable political opposition to the dominant Republican Party in Minnesota during this period, and that the Farmer-Labor Party was a long-term movement comprised of a fractious coalition of urban-labor and rural-agrarian constituents held together by a series of leaders. The party’s emergence and rise to power in the early 1920s was fueled by a number of factors, however the creation and the continuing governance of the party and its association was initiated and administered by a Twin Cities-based urban-labor leadership (and as such, the movement was not merely another chapter of agrarian protest politics). This urban-labor leadership nucleus effectively absorbed the state’s Nonpartisan League by 1922, joined that movement with its own emerging third party urban-labor movement, and then transformed this new coalition into the Farmer-Labor Party. The party’s demise was caused by a number of factors which coalesced in the late 1930s, including the implementation of federal farm and labor policies under Franklin Roosevelt’s New Deal, corruption within the party, a decline in the party’s leadership, and increased factional conflict based on divisions of the rural-agrarian and urban-labor sectors of the party

Galaxy Zoo: Multimergers and the Millennium Simulation

We present a catalogue of 39 multiple mergers, found using the mergers catalogue of the Galaxy Zoo project for z <0.1, and compare them to corresponding semi-analytical galaxies from the Millennium Simulation. We estimate the (volume-limited) multimerger fraction of the local Universe using our sample and find it to be at least 2 orders of magnitude less than binary mergers - in good agreement with the simulations (especially the Munich group). We then investigate the properties of galaxies in binary mergers and multimergers (morphologies, colours, stellar masses and environment) and compare these results with those predicted by the semi-analytical galaxies. We find that multimergers favour galaxies with properties typical of elliptical morphologies and that this is in qualitative agreement with the models. Studies of multimergers thus provide an independent (and largely corroborating) test of the Millennium semi-analytical models.Peer reviewe

Classical Trajectories for Complex Hamiltonians

It has been found that complex non-Hermitian quantum-mechanical Hamiltonians may have entirely real spectra and generate unitary time evolution if they possess an unbroken \cP\cT symmetry. A well-studied class of such Hamiltonians is $H= p^2+x^2(ix)^\epsilon$ ($\epsilon\geq0$). This paper examines the underlying classical theory. Specifically, it explores the possible trajectories of a classical particle that is governed by this class of Hamiltonians. These trajectories exhibit an extraordinarily rich and elaborate structure that depends sensitively on the value of the parameter $\epsilon$ and on the initial conditions. A system for classifying complex orbits is presented.Comment: 24 pages, 34 figure

A Detailed Analogy of Network Simulators � NS1, NS2, NS3 and NS4

Networking is a field of Computer Science where the researchers are dependent on simulators and simulation as the devices used in networking are very costly and complex. It is not easily possible to establish a computer network in real world easily, also direct installation of network devices and cables is not feasible. A simulator is a low cost mechanism which can be used to deploy a network and implement protocols and test the feasibility of the network. NS aka Network Simulator is one such low cost tool, which is available as open source software to network designers. With time simulators have evolved and now Network simulators can simulate wireless networks and advanced mobile networks. The Network Simulator evolution took place with the methodologies and coding technologies. Medium level language like C++ was used in NS1 and later in NS2 we started using easy modeling language like OTCL and C++. In NS3 we can now do coding with more powerful language Python, it also has support for OTCL and C++. High level and advanced language like P4 is the recent one to be used in NS4. The network simulators are now more powerful and fast, as compared to earlier generations of simulators. This paper talks about these advancements that have taken place in the history of Network Simulators and future scopes of NS

A Change of Perspective: The Pre-Graduate Expectations versus Post-College Experiences of Theatre Arts Majors

University of Minnesota Ph.D. dissertation. 2018. Major: Organizational Leadership, Policy, and Development. Advisor: Darwin Hendel. 1 computer file (PDF); 272 pages.Though there has been a great deal of research on the transition into college, there has been relatively little research on the transition out of college. This is particularly true in relation to theatre arts majors. Though recent graduates face many challenges post-college, there has been minimal exploration done on how graduates experience discrepancies between their pre-graduate expectations formed in college versus their actual post-college experiences. This qualitative study sought to explore the post-college transition experiences of 20 recent theatre arts baccalaureates (12 males and 8 females) and the discrepancy between their pre-graduate expectations and post-college experiences based on Schlossberg’s Transition Theory (1984) as a conceptual model. This model posits the type of transition (non-event), and four coping resources (situation, support, self, and strategies) for managing individual transition experiences. The results of the study identified four primary themes which impacted the post-college experiences of the study participants: (a) Undergraduate Preparedness, (b) Career, Finances, and Other Factors, (c) Discrepancy between Pre-Graduate Expectations versus Post-College Experiences, and (d) Artist Identity. In addition, the results of the study revealed that each of the 20 participants encountered a discrepancy between their pre-graduate expectations versus post-college experiences. The results of the study provide support for adding a new dimension to Schlossberg’s Transition Theory model as it relates to a psychological response that occurs within an individual when they encounter a discrepancy between what they thought would happen after college and what actually occurred post-college. A micro-transition is the psychological “change of perspective” (COP) by an individual regarding the macro-transition experience that results from the realization of a discrepancy between expectations and actual experiences. Implications for this study address undergraduate programming, faculty preparation, and alumni and theater organizations to better prepare theatre arts baccalaureates for the transition to post-college life

Galaxy Zoo : Building the low-mass end of the red sequence with local post-starburst galaxies

We present a study of local post-starburst galaxies (PSGs) using the photometric and spectroscopic observations from the Sloan Digital Sky Survey and the results from the Galaxy Zoo project. We find that the majority of our local PSG population have neither early- nor late-type morphologies but occupy a well-defined space within the colour-stellar mass diagram, most notably, the low-mass end of the 'green valley' below the transition mass thought to be the mass division between low-mass star-forming galaxies and high-mass passively evolving bulge-dominated galaxies. Our analysis suggests that it is likely that local PSGs will quickly transform into 'red', low-mass early-type galaxies as the stellar morphologies of the 'green' PSGs largely resemble that of the early-type galaxies within the same mass range. We propose that the current population of PSGs represents a population of galaxies which is rapidly transitioning between the star-forming and the passively evolving phases. Subsequently, these PSGs will contribute towards the build-up of the low-mass end of the 'red sequence' once the current population of young stars fade and stars are no longer being formed. These results are consistent with the idea of 'downsizing' where the build-up of smaller galaxies occurs at later epochs.Peer reviewe

Galaxy Zoo 1 : Data Release of Morphological Classifications for nearly 900,000 galaxies

Morphology is a powerful indicator of a galaxy's dynamical and merger history. It is strongly correlated with many physical parameters, including mass, star formation history and the distribution of mass. The Galaxy Zoo project collected simple morphological classifications of nearly 900,000 galaxies drawn from the Sloan Digital Sky Survey, contributed by hundreds of thousands of volunteers. This large number of classifications allows us to exclude classifier error, and measure the influence of subtle biases inherent in morphological classification. This paper presents the data collected by the project, alongside measures of classification accuracy and bias. The data are now publicly available and full catalogues can be downloaded in electronic format from http://data.galaxyzoo.org.Comment: Accepted by MNRAS, 14 pages. Updated to match final version; problem with table 7 header fixed. Full tables available at http://data.galaxyzoo.or

Peculiar early-type galaxies in the SDSS Stripe82

We explore the properties of `peculiar' early-type galaxies (ETGs) in the local Universe, that show (faint) morphological signatures of recent interactions such as tidal tails, shells and dust lanes. Standard-depth (51s exposure) multi-colour galaxy images from the Sloan Digital Sky Survey (SDSS) are combined with the significantly (2 mags) deeper monochromatic images from the public SDSS Stripe82 to extract, through careful visual inspection, a robust sample of nearby, luminous ETGs, including a subset of ~70 peculiar systems. 18% of ETGs exhibit signs of disturbed morphologies (e.g. shells), while 7% show evidence of dust lanes and patches. The peculiar ETG population is found to preferentially inhabit low-density environments (outskirts of clusters, groups or the field). An analysis of optical emission-line ratios indicates that the fraction of peculiar ETGs that are Seyferts or LINERs (19.4%) is twice the corresponding values in their relaxed counterparts (10.1%). LINER-like emission is the dominant type of nebular activity in all ETG classes, plausibly driven by stellar photoionisation associated with recent star formation. An analysis of UV-optical colours indicates that, regardless of the luminosity range being considered, the fraction of peculiar ETGs that have experienced star formation in the last Gyr is a factor of ~1.5 higher than that in their relaxed counterparts. The spectro-photometric results strongly suggest that the interactions that produce the morphological peculiarities also induce low-level recent star formation which, based on the recent literature, are likely to contribute a few percent of the stellar mass over the last 1 Gyr. The catalogue of galaxies that forms the basis of this paper can be obtained at: http://www.mssl.ucl.ac.uk/~ska/stripe82/skaviraj_stripe82.dat or on request from the author.Comment: MNRAS in pres

Galaxy Zoo: Dust in Spirals

We investigate the effect of dust on spiral galaxies by measuring the inclination-dependence of optical colours for 24,276 well-resolved SDSS galaxies visually classified in Galaxy Zoo. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4 magnitudes for the ugri passbands. We split the sample into "bulgy" (early-type) and "disky" (late-type) spirals using the SDSS fracdeV (or f_DeV) parameter and show that the average face-on colour of "bulgy" spirals is redder than the average edge-on colour of "disky" spirals. This shows that the observed optical colour of a spiral galaxy is determined almost equally by the spiral type (via the bulge-disk ratio and stellar populations), and reddening due to dust. We find that both luminosity and spiral type affect the total amount of extinction, with "disky" spirals at M_r ~ -21.5 mags having the most reddening. This decrease of reddening for the most luminous spirals has not been observed before and may be related to their lower levels of recent star formation. We compare our results with the latest dust attenuation models of Tuffs et al. We find that the model reproduces the observed trends reasonably well but overpredicts the amount of u-band attenuation in edge-on galaxies. We end by discussing the effects of dust on large galaxy surveys and emphasize that these effects will become important as we push to higher precision measurements of galaxy properties and their clustering.Comment: MNRAS in press. 25 pages, 22 figures (including an abstract comparing GZ classifications with common automated methods for selecting disk/early type galaxies in SDSS data). v2 corrects typos found in proof