Hawking Radiation in the Ghost Condensate is Non-Thermal

We consider a Schwarzschild black hole immersed in a ghost condensate background. It is shown that the Hawking radiation in the quanta of small perturbations around this background is highly suppressed- in particular it is not given by a thermal spectrum. This result is in accord with observations that such black holes can be used to violate the generalized second law of thermodynamics, and thus cannot have a standard entropy/area relation.Comment: 26 pages; v2: reference added, missing Christoffel symbols included in appendix, minor typos corrected in equations (39) and (50

Constructions of cinematic space : spatial practice at the intersection of film and theory

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Comparative Media Studies, 2005.Includes bibliographical references (p. 143-146).This thesis is an attempt to bring fresh insights to current understandings of cinematic space and the relationship between film, architecture, and the city. That attempt is situated in relation to recent work by Michael Hardt and Antonio Negri, Saskia Sassen, and others on the importance of the city in the current global framework, along with the growing body of literature on film, architecture, and urban space. Michel De Certeau's threefold critique of the city, set forth in The practices of Everyday Life, structures a comparative analysis of six primary films, aired as follows, with one air for each of three chapters-Jacques Tati's lay Time and Edward Yang's Yi Yi, Vittorio De Sica's Bicycle Thieves and Wang Xiaoshuai's Beijing Bicycle, and Franqois Truffaut's The 400 Blows and Mira Nair's Salaam Bombay!. Along with De Certeau's notions of satial ractice, walking rhetorics, and the pedestrian speech act, the philosophy of Gilles Deleuze-including work from the Cinema texts and A Thousand plateaus-is developed in relation to existent film theory on movement, time, and space.(cont.) The analysis operates as a kind of mediation between an active set of spatial theories-a mediation which uses traditional techniques of film analysis and critical theory to instigate a negotiation around the topic of (cinematic) space. That negotiation implies a common ground on which the film texts and theories are read against and in addition to one another, allowing each to contribute in its own right to the setting u of a series of terms-what I refer to as a "spatial grammar"-proper to both film and theory. The spatial grammar thus comprises a more abstract theoretical lane-a palimpsest on which resides a classic body of work on cinematic space (including Andre Bazin, Stephen Heath, and Kristin Thomson), and on which I layer the work of De Certeau, Deleuze, Fredric Jameson, and others.by Brian R. Jacobson.S.M

A Low-noise Micromachined Millimeter-Wave Heterodyne Mixer using Nb Superconducting Tunnel Junctions

A heterodyne mixer with a micromachined horn antenna and a superconductor-insulator-superconductor (SIS) tunnel junction as mixing element is tested in the W-band (75-115 GHz) frequency range. Micromachined integrated horn antennas consist of a dipole antenna suspended on a thin Si3N4 dielectric membrane inside a pyramidal cavity etched in silicon. The mixer performance is optimized by using a backing plane behind the dipole antenna to tune out the capacitance of the tunnel junction. The lowest receiver noise temperature of 30 +/- 3 K (without any correction) is measured at 106 GHz with a 3-dB bandwidth of 8 GHz. This sensitivity is comparable to the state-of-the-art waveguide and quasi-optical SIS receivers, showing the potential use of micromachined horn antennas in imaging arrays

Nitric acid scavenging by mineral and biomass burning aerosols

The abundance of gas phase nitric acid in the upper troposphere is overestimated by global chemistry-transport models, especially during the spring and summer seasons. Recent aircraft data obtained over the central US show that mineral aerosols were abundant in the upper troposphere during spring. Chemical reactions on mineral dust may provide an important sink for nitric acid. In regions where the mineral dust abundance is low in the upper troposphere similar HNO3 removal processes may occur on biomass burning aerosols. We propose that mineral and biomass burning aerosols may provide an important global sink for gas phase nitric acid, particularly during spring and summer when aerosol composition in the upper troposphere may be greatly affected by dust storms from east Asia or tropical biomass burning plumes

Economic Impact of the Cleantech Sector in the Austin-Round Rock-San Marcos MSA

Economic impact report for the clean technology sector in central Texas, commissioned by CleanTX and supported by the Austin Technology Incubator and Civic Analytics. The study finds that the cleantech sector in the Austin region directly employs nearly 20,000 individuals and contributes approximately $2.5 billion to the region's GDP. In addition, it projects cleantech employment from 2014-2020 to grow 11.24% in the Austin MSA, as compared with 9.3% growth in the sector over the same period at the state level, and 6.37% nationally. The report identifies seven specific technology areas which represent opportunities for growth: renewables; energy storage and "smart grid" technologies; smart cities and resilient infrastructure; autonomous vehicles and connected mobility; water management; recycling and waste management; and advanced manufacturing.IC2 Institut

High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey

The SkyMapper Southern Sky Survey is carrying out a search for the most metal-poor stars in the Galaxy. It identifies candidates by way of its unique filter set that allows for estimation of stellar atmospheric parameters. The set includes a narrow filter centered on the Ca II K 3933A line, enabling a robust estimate of stellar metallicity. Promising candidates are then confirmed with spectroscopy. We present the analysis of Magellan-MIKE high-resolution spectroscopy of 122 metal-poor stars found by SkyMapper in the first two years of commissioning observations. 41 stars have [Fe/H] <= -3.0. Nine have [Fe/H] <= -3.5, with three at [Fe/H] ~ -4. A 1D LTE abundance analysis of the elements Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, Ba and Eu shows these stars have [X/Fe] ratios typical of other halo stars. One star with low [X/Fe] [X/Fe values appears to be "Fe-enhanced," while another star has an extremely large [Sr/Ba] ratio: >2. Only one other star is known to have a comparable value. Seven stars are "CEMP-no" stars ([C/Fe] > 0.7, [Ba/Fe] < 0). 21 stars exhibit mild r-process element enhancements (0.3 <=[Eu/Fe] < 1.0), while four stars have [Eu/Fe] >= 1.0. These results demonstrate the ability to identify extremely metal-poor stars from SkyMapper photometry, pointing to increased sample sizes and a better characterization of the metal-poor tail of the halo metallicity distribution function in the future.Comment: Minor corrections to text, missing data added to Tables 3 and 4; updated to match published version. Complete tables included in sourc

High-Frequency (> 100 GHz) Electronic Devices

Contains reports on four research projects, the research facility and a list of publications.Defense Advanced Research Projects Agency Contract MDA972-90-C-0021National Aeronautics and Space Administration Grant NAG2-693National Science Foundation Grant ECS 91-0933

Utilization of HIV-1 envelope V3 to identify X4- and R5-specific Tat and LTR sequence signatures.

BACKGROUND: HIV-1 entry is a receptor-mediated process directed by the interaction of the viral envelope with the host cell CD4 molecule and one of two co-receptors, CCR5 or CXCR4. The amino acid sequence of the third variable (V3) loop of the HIV-1 envelope is highly predictive of co-receptor utilization preference during entry, and machine learning predictive algorithms have been developed to characterize sequences as CCR5-utilizing (R5) or CXCR4-utilizing (X4). It was hypothesized that while the V3 loop is predominantly responsible for determining co-receptor binding, additional components of the HIV-1 genome may contribute to overall viral tropism and display sequence signatures associated with co-receptor utilization. RESULTS: The accessory protein Tat and the HlV-1 long terminal repeat (LTR) were analyzed with respect to genetic diversity and compared by Jensen-Shannon divergence which resulted in a correlation with both mean genetic diversity as well as the absolute difference in genetic diversity between R5- and X4-genome specific trends. As expected, the V3 domain of the gp120 protein was enriched with statistically divergent positions. Statistically divergent positions were also identified in Tat amino acid sequences within the transactivation and TAR-binding domains, and in nucleotide positions throughout the LTR. We further analyzed LTR sequences for putative transcription factor binding sites using the JASPAR transcription factor binding profile database and found several putative differences in transcription factor binding sites between R5 and X4 HIV-1 genomes, specifically identifying the C/EBP sites I and II, and Sp site III to differ with respect to sequence configuration for R5 and X4 LTRs. CONCLUSION: These observations support the hypothesis that co-receptor utilization coincides with specific genetic signatures in HIV-1 Tat and the LTR, likely due to differing transcriptional regulatory mechanisms and selective pressures applied within specific cellular targets during the course of productive HIV-1 infection