Active Galaxies and the Study of Black Hole Demographics

We discuss the critical importance of black hole mass indicators based on scaling relations in active galaxies. We highlight outstanding uncertainties in these methods and potential paths to substantial progress in the next decade.Comment: 4 pages, 1 figure, Invited review to appear in PAS

A solar water heater for remote communities

The RADG has been developing a solar water heater suitable for use in remote areas. The original inspiration for this project was to provide hot water for remote Aboriginal communities. It was felt that a regular and plentiful supply of hot water would encourage showering and laundering and hence improve personal hygiene. Electric, fuel burning and solar water heaters are currently used in some communities. Solar water heaters are attractive for remote areas because they stand alone i.e. they require no external fuel source. Wood has traditionally been used as a fuel by Aboriginal people, but in permanent communities the demand on this resource may have a large impact on the environment. Solar water heaters can help to reduce this demand

"Low-state" Black Hole Accretion in Nearby Galaxies

I summarize the main observational properties of low-luminosity AGNs in nearby galaxies to argue that they are the high-mass analogs of black hole X-ray binaries in the "low/hard" state. The principal characteristics of low-state AGNs can be accommodated with a scenario in which the central engine is comprised of three components: an optically thick, geometrically accretion disk with a truncated inner radius, a radiatively inefficient flow, and a compact jet.Comment: 8 pages. To appear in From X-ray Binaries to Quasars: Black Hole Accretion on All Mass Scales, ed. T. J. Maccarone, R. P. Fender, and L. C. Ho (Dordrecht: Kluwer

X-ray Properties of Intermediate-mass Black Holes in Active Galaxies. III. Spectral Energy Distribution and Possible Evidence for Intrinsically X-ray-weak AGNs

We present a systematic X-ray study, the third in a series, of 49 active galactic nuclei with intermediate-mass black holes (IMBH; ~10^5-10^6 M_sun) using Chandra observations. We detect 42 out of 49 targets with a 0.5-2 keV X-ray luminosity 10^41-10^43 erg/s. We perform spectral fitting for the 10 objects with enough counts (>200), and they are all well fit by a simple power-law model modified by Galactic absorption, with no sign of significant intrinsic absorption. While we cannot fit the X-ray spectral slope directly for the rest of the sample, we estimate it from the hardness ratio and find a range of photon indices consistent with those seen in more luminous and massive objects. The X-ray-to-optical spectral slope (alphaox) of our IMBH sample is systematically flatter than in active galaxies with more massive black holes, consistent with the well-known correlation between alphaox and UV luminosity. Thanks to the wide dynamic range of our sample, we find evidence that alphaox increases with decreasing M_BH as expected from accretion disk models, where the UV emission systematically decreases as M_BH decreases and the disk temperature increases. We also find a long tail toward low alphaox values. While some of these sources may be obscured, given the high L_bol/L_Eddington values in the sample, we argue that some may be intrinsically X-ray-weak, perhaps owing to a rare state that radiates very little coronal emission.Comment: 13 pages (double columns), 2 tables, 9 figures, ApJ accepte

Mobility and Saturation Velocity in Graphene on SiO2

We examine mobility and saturation velocity in graphene on SiO2 above room temperature (300-500 K) and at high fields (~1 V/um). Data are analyzed with practical models including gated carriers, thermal generation, "puddle" charge, and Joule heating. Both mobility and saturation velocity decrease with rising temperature above 300 K, and with rising carrier density above 2x10^12 cm^-2. Saturation velocity is >3x10^7 cm/s at low carrier density, and remains greater than in Si up to 1.2x10^13 cm^-2. Transport appears primarily limited by the SiO2 substrate, but results suggest intrinsic graphene saturation velocity could be more than twice that observed here

Triangle anomaly in Weyl semi-metals

Weyl semimetals possess massless chiral quasi-particles, and are thus affected by the triangle anomalies. We discuss the features of the chiral magnetic and chiral vortical effects specific to Weyl semimetals, and then propose three novel phenomena caused by the triangle anomalies in this material: 1) anomaly cooling; 2) charge transport by soliton waves as described by the Burgers' equation, and 3) the shift of the BKT phase transition of superfluid vortices coupled to Weyl fermions. In addition, we establish the conditions under which the chiral magnetic current exists in real materials.Comment: v3. Improved figures, minor changes in the text, 24 pages, 3 figure

FACTORS AFFECTING CONSUMER PREFERENCES FOR MAJOR FOOD MARKETS IN TAIWAN

The Food Industry Research and Development Institute conducted a nationwide survey of food consumption in Taiwan in 1999. A sample of 1200 consumers responded to a questionnaire, which asked whether there was a use/visit experience in the past year for each of six types of food markets: traditional vegetable market, supermarket, hypermarket, consumer cooperative, chain convenience store, and grocery store. Questions also asked which types of food markets consumers used most frequently for the purchase of fresh foods, planned purchases or occasional purchases of processed foods, and what factors influenced consumers to choose their most frequently used market. Nearly 84 percent of surveyed consumers have used/visited traditional vegetable markets in the past year, while 47 percent choose traditional markets as their most frequented marketplace for buying fresh food in Taiwan. Some 81 percent of surveyed consumers have used or visited a supermarket in past year, while 17.7 percent and 29.0 percent choose supermarkets as the most frequented marketplace for planned and occasional purchases of processed foods, respectively. We apply stepwise logistic regression to identify significant sociodemographic factors (such as gender, age, and others) which influence the choice of each of the six major types of food markets and to identify the promotional factors which positively or negatively influence consumers' preferences for the most often used market. Female consumers have almost four times higher odds of frequently using traditional vegetable markets in the past year. The unmarried, divorced/widowed, and/or those who had higher family monthly incomes demonstrate lower odds of frequently using traditional markets. For purchases of fresh foods, female respondents, older consumers, and/or those living in northern Taiwan have higher odds of choosing traditional vegetable markets as the most frequently used market, while occupation "chief," and those with higher levels of education have lower odds of choosing traditional markets. Price level influences consumers positively in choosing traditional vegetable markets, while products with mark registrations, such as GMP or CAS, negatively influence this choice. For planned purchases of processed foods, older consumers are more likely than others to choose traditional vegetable markets, and price level is also a positive influence for choosing these markets. For occasional purchases of processed foods, manual laborers and/or those living in northern Taiwan have higher odds of choosing traditional vegetable markets, while unmarried respondents have lower odds. Price level and products with nutrition labeling are positive promotional factors influencing consumers to choose traditional vegetable markets. For the other five market types, sociodemographic factors influence consumers' choices of markets differently in each case, but marketing factors also influence choices of which type of marketplace to use most frequently.Consumer/Household Economics,