University of Wisconsin–Milwaukee

About: University of Wisconsin–Milwaukee is a education organization based out in Milwaukee, Wisconsin, United States. It is known for research contribution in the topics: Population & Gravitational wave. The organization has 11839 authors who have published 28034 publications receiving 936438 citations. The organization is also known as: UWM & University of Wisconsin-Milwaukee.

GLEAM: The GaLactic and Extragalactic All-sky MWA survey

Abstract: GLEAM, the GaLactic and Extragalactic All-sky MWA survey, is a survey of the entire radio sky south of declination +25 deg at frequencies between 72 and 231 MHz, made with the Murchison Widefield Array (MWA) using a drift scan method that makes efficient use of the MWA's very large field-of-view. We present the observation details, imaging strategies and theoretical sensitivity for GLEAM. The survey ran for two years, the first year using 40 kHz frequency resolution and 0.5 s time resolution; the second year using 10 kHz frequency resolution and 2 s time resolution. The resulting image resolution and sensitivity depends on observing frequency, sky pointing and image weighting scheme. At 154 MHz the image resolution is approximately 2.5 x 2.2/cos(DEC+26.7) arcmin with sensitivity to structures up to ~10 deg in angular size. We provide tables to calculate the expected thermal noise for GLEAM mosaics depending on pointing and frequency and discuss limitations to achieving theoretical noise in Stokes I images. We discuss challenges, and their solutions, that arise for GLEAM including ionospheric effects on source positions and linearly polarised emission, and the instrumental polarisation effects inherent to the MWA's primary beam.

Dynamical mass ejection from black hole-neutron star binaries

Abstract: We investigate properties of material ejected dynamically in the merger of black hole-neutron star binaries by numerical-relativity simulations. We systematically study the dependence of ejecta properties on the mass ratio of the binary, spin of the black hole, and equation of state of the neutron-star matter. Dynamical mass ejection is driven primarily by tidal torque, and the ejecta is much more anisotropic than that from binary neutron star mergers. In particular, the dynamical ejecta is concentrated around the orbital plane with a half opening angle of 10\ifmmode^\circ\else\textdegree\fi{}--20\ifmmode^\circ\else\textdegree\fi{} and often sweeps out only a half of the plane. The ejecta mass can be as large as $\ensuremath{\sim}0.1{M}_{\ensuremath{\bigodot}}$, and the velocity is subrelativistic with $\ensuremath{\sim}0.2--0.3c$ for typical cases. The ratio of the ejecta mass to the bound mass (disk and fallback components) is larger, and the ejecta velocity is larger, for larger values of the binary mass ratio, i.e., for larger values of the black-hole mass. The remnant black hole-disk system receives a kick velocity of $O(100)\text{ }\text{ }\mathrm{km}\text{ }{\mathrm{s}}^{\ensuremath{-}1}$ due to the ejecta linear momentum, and this easily dominates the kick velocity due to gravitational radiation. Structures of postmerger material, velocity distribution of the dynamical ejecta, fallback rates, and gravitational waves are also investigated. We also discuss the effect of ejecta anisotropy on electromagnetic counterparts, specifically a macronova/kilonova and synchrotron radio emission, developing analytic models.

A database encryption system with subkeys

Abstract: A new cryptosystem that is suitable for database encryption is presented. The system has the important property of having subkeys that allow the encryption and decryption of fields within a record. The system is based on the Chinese Remainder Theorem.

Nonperturbative effects of vacuum energy on the recent expansion of the universe

Abstract: We show that the vacuum energy of a free quantized field of very low mass can significantly alter the recent expansion of the universe. The effective action of the theory is obtained from a non-perturbative sum of scalar curvature terms in the propagator. We numerically investigate the semiclassical Einstein equations derived from it. As a result of non-perturbative quantum effects, the scalar curvature of the matter-dominated universe stops decreasing and approaches a constant value. The universe in our model evolves from an open matter-dominated epoch to a mildly inflating de Sitter expansion. The Hubble constant during the present de Sitter epoch, as well as the time at which the transition occurs from matter-dominated to de Sitter expansion, are determined by the mass of the field and by the present matter density. The model provides a theoretical explanation of the observed recent acceleration of the universe, and gives a good fit to data from high-redshift Type Ia supernovae, with a mass of about 10^{-33} eV, and a current ratio of matter density to critical density, Omega_0 <0.4 . The age of the universe then follows with no further free parameters in the theory, and turns out to be greater than 13 Gyr. The model is spatially open and consistent with the possibility of inflation in the very early universe. Furthermore, our model arises from the standard renormalizable theory of a free quantum field in curved spacetime, and does not require a cosmological constant or the associated fine-tuning.

Advertising to Bilingual Consumers: The Impact of Code-Switching on Persuasion

Abstract: Building on a sociolinguistic framework, our research explores the impact of code‐switching on the persuasiveness of marketing messages. Code‐switching refers to mixing languages within a sentence, a common practice among bilingual consumers. We investigate how responses to different types of code‐switched messages can provide insight into bilingual consumers’ persuasion processes. A pilot study reveals a code‐switching direction effect such that minority‐language slogans switching to the majority language result in greater persuasion than majority‐language slogans switching to the minority language. The effect is attributed to the salience of the code‐switched word in the slogan. Study 1 explores this code‐switching direction effect in more detail and shows that when associations toward the minority language are positive, the code‐switching direction effect is reversed.