Seeking Information Using Search Engines: The Impact of Negation on Judgments

We examine how online searches lead to judgment formation in two contexts where statements are negated differently. In one context, a statement (of the form “if P then Q”) is negated using “not” (as in “if P then not Q”), while in the other context, it is negated using a different term or phrase (as in “if P then R”). We show that online searches to find information about the validity of this statement generate different results in these contexts. Our findings contribute to extant work on online searches by suggesting that when individuals test the validity of a statement using search engines, their searches lead to categorically different results contingent on the search context. From a practical standpoint, we make recommendations to search engine developers and content providers so online searches generate more inclusive results

Improving the Quality of Knowledge Assets: Governance Mechanisms and Their Implications

Knowledge management initiatives are less likely to be successful if knowledge repositories do not provide high-quality knowledge assets. Two mechanisms employed by organizations to ensure knowledge quality are using experts to control or edit users’ contributions (such as in a refereed repository), and using a community of users to review, rate, or edit existing contributions (such as in a community-driven wiki). The goal of this paper is to explore these two mechanisms by drawing upon the concept of societal governance from sociology, identify the conditions under which they are preferable, and discuss their impact on how users contribute to and reuse information from knowledge repositories. Propositions are suggested and implications are discussed

Navigating Workload Compatibility Between a Recommender System and a NoSQL Database: An Interactive Tutorial

In this tutorial, the issue of compatibility between a big data storage technology and an analytic workload is explored using a fictitious streaming company as an example. The tutorial offers an interactive approach to help students understand the importance of considering workload compatibility when adopting new technologies. We provide instructors with two Jupyter Notebooks that analyze the compatibility, a detailed instructor guide on how to execute these notebooks, lessons learned, and appendices containing solutions and explanations. This tutorial provides a valuable resource for instructors teaching courses in database systems, big data, and analytic concepts, helping students develop practical skills to navigate the complexities of big data technologies effectively

Purchase Behaviors During Emergencies: Exploratory Analyses and Predictive Models

In this study, we distinguish between traditional emergency events (i.e., those that occur frequently) and novel emergency events (i.e., those that occur rarely in one’s lifetime). We examine consumers’ shopping behaviors during both types of emergency events. Using data from a U.S. supermarket chain, we answer three research questions. First, we conduct multiple cluster analyses and identify three distinct shopping behaviors during emergency events, namely strategic, routine, and stocking. Second, we examine how consumers change their shopping behaviors toward novel emergency events and find that majority of consumers continue to engage in routine shopping behaviors. Third, we examine how to predict shopping behaviors before emergency events and show that all three types of shopping behaviors can be predicted with reasonable levels of accuracy based on consumers’ spending before emergency events

The Black Hole in the Compact, High-dispersion Galaxy NGC 1271

Located in the Perseus cluster, NGC 1271 is an early-type galaxy with a small effective radius of 2.2 kpc and a large stellar velocity dispersion of 276 km/s for its K-band luminosity of 8.9x10^{10} L_sun. We present a mass measurement for the black hole in this compact, high-dispersion galaxy using observations from the integral field spectrograph NIFS on the Gemini North telescope assisted by laser guide star adaptive optics, large-scale integral field unit observations with PPAK at the Calar Alto Observatory, and Hubble Space Telescope WFC3 imaging observations. We are able to map out the stellar kinematics on small spatial scales, within the black hole sphere of influence, and on large scales that extend out to four times the galaxy's effective radius. We find that the galaxy is rapidly rotating and exhibits a sharp rise in the velocity dispersion. Through the use of orbit-based stellar dynamical models, we determine that the black hole has a mass of (3.0^{+1.0}_{-1.1}) x 10^9 M_sun and the H-band stellar mass-to-light ratio is 1.40^{+0.13}_{-0.11} M_sun/L_sun (1-sigma uncertainties). NGC 1271 occupies the sparsely-populated upper end of the black hole mass distribution, but is very different from the Brightest Cluster Galaxies (BCGs) and giant elliptical galaxies that are expected to host the most massive black holes. Interestingly, the black hole mass is an order of magnitude larger than expectations based on the galaxy's bulge luminosity, but is consistent with the mass predicted using the galaxy's bulge stellar velocity dispersion. More compact, high-dispersion galaxies need to be studied using high spatial resolution observations to securely determine black hole masses, as there could be systematic differences in the black hole scaling relations between these types of galaxies and the BCGs/giant ellipticals, thereby implying different pathways for black hole and galaxy growth.Comment: accepted for publication in Ap

Study of multi black hole and ring singularity apparent horizons

We study critical black hole separations for the formation of a common apparent horizon in systems of $N$ - black holes in a time symmetric configuration. We study in detail the aligned equal mass cases for $N=2,3,4,5$, and relate them to the unequal mass binary black hole case. We then study the apparent horizon of the time symmetric initial geometry of a ring singularity of different radii. The apparent horizon is used as indicative of the location of the event horizon in an effort to predict a critical ring radius that would generate an event horizon of toroidal topology. We found that a good estimate for this ring critical radius is $20/(3\pi) M$. We briefly discuss the connection of this two cases through a discrete black hole 'necklace' configuration.Comment: 31 pages, 21 figure

Duality invariance of non-anticommutative N=1/2 supersymmetric U(1) gauge theory

A parent action is introduced to formulate (S-) dual of non-anticommutative N=1\2 supersymmetric U(1) gauge theory. Partition function for parent action in phase space is utilized to establish the equivalence of partition functions of the theories which this parent action produces. Thus, duality invariance of non-anticommutative N=1\2 supersymmetric U(1) gauge theory follows. The results which we obtained are valid at tree level or equivalently at the first order in the nonanticommutativity parameter C_{\mu\nu}.Comment: 12 pages, some comments and references are added. To appear in JHE

A \u3cem\u3eChandra\u3c/em\u3e Survey of Supermassive Black Holes with Dynamical Mass Measurements

We present Chandra observations of 12 galaxies that contain supermassive black holes (SMBHs) with dynamical mass measurements. Each galaxy was observed for 30 ks and resulted in a total of 68 point-source detections in the target galaxies including SMBH sources, ultraluminous X-ray sources (ULXs), and extragalactic X-ray binaries. Based on our fits of the X-ray spectra, we report fluxes, luminosities, Eddington ratios, and slope of the power-law spectrum. Normalized to the Eddington luminosity, the 2-10 keV band X-ray luminosities of the SMBH sources range from 10-8 to 10-6, and the power-law slopes are centered at ~2 with a slight trend toward steeper (softer) slopes at smaller Eddington fractions, implying a change in the physical processes responsible for their emission at low accretion rates. We find 20 ULX candidates, of which 6 are likely (\u3e90% chance) to be true ULXs. The most promising ULX candidate has an isotropic luminosity in the 0.3-10 keV band of 1.0+0.6 - 0.3 × 1040 erg s-1

A \u3cem\u3eChandra\u3c/em\u3e Survey of Supermassive Black Holes with Dynamical Mass Measurements

We present Chandra observations of 12 galaxies that contain supermassive black holes (SMBHs) with dynamical mass measurements. Each galaxy was observed for 30 ks and resulted in a total of 68 point-source detections in the target galaxies including SMBH sources, ultraluminous X-ray sources (ULXs), and extragalactic X-ray binaries. Based on our fits of the X-ray spectra, we report fluxes, luminosities, Eddington ratios, and slope of the power-law spectrum. Normalized to the Eddington luminosity, the 2-10 keV band X-ray luminosities of the SMBH sources range from 10-8 to 10-6, and the power-law slopes are centered at ~2 with a slight trend toward steeper (softer) slopes at smaller Eddington fractions, implying a change in the physical processes responsible for their emission at low accretion rates. We find 20 ULX candidates, of which 6 are likely (\u3e90% chance) to be true ULXs. The most promising ULX candidate has an isotropic luminosity in the 0.3-10 keV band of 1.0+0.6 - 0.3 × 1040 erg s-1