206 research outputs found
A HT3 Platform for Rapid Prototyping and High Performance Reconfigurable Computing
FPGAs as reconfigurable devices play an important role in both rapid prototyping and high performance reconfigurable computing. Usually, FPGA vendors help the users with pre-designed cores, for instance for various communication protocols. However, this is only true for widely used protocols. In the use case described here, the target application may benefit from a tight integration of the FPGA in a computing system. Typical commodity protocols like PCI Express may not fulfill these demands. HyperTransport (HT), on the other hand, allows connecting directly and without intermediate bridges or protocol conversion to a processor interface. As a result, communication costs between the FPGA unit and both processor and main memory are minimal. In this paper we present an HT3 interface for Stratix IV based FPGAs, which allows for minimal latencies and high bandwidths between processor and device and main memory and device. Designs targeting a HT connection can now be prototyped in real world systems. Furthermore, this design can be leveraged for acceleration tasks, with the minimal communication costs allowing fine-grain work deployment and the use of cost-efficient main memory instead of size-limited and costly on-device memory
Dust Temperatures in the Infrared Space Observatory Atlas of Bright Spiral Galaxies
We examine far-infrared and submillimeter spectral energy distributions for
galaxies in the Infrared Space Observatory Atlas of Bright Spiral Galaxies. For
the 71 galaxies where we had complete 60-180 micron data, we fit blackbodies
with lambda^-1 emissivities and average temperatures of 31 K or lambda^-2
emissivities and average temperatures of 22 K. Except for high temperatures
determined in some early-type galaxies, the temperatures show no dependence on
any galaxy characteristic. For the 60-850 micron range in eight galaxies, we
fit blackbodies with lambda^-1, lambda-2, and lambda^-beta (with beta variable)
emissivities to the data. The best results were with the lambda^-beta
emissivities, where the temperatures were ~30 K and the emissivity coefficient
beta ranged from 0.9 to 1.9. These results produced gas to dust ratios that
ranged from 150 to 580, which were consistent with the ratio for the Milky Way
and which exhibited relatively little dispersion compared to fits with fixed
emissivities.Comment: AJ, 2003, in pres
Presentation of CMV immediate-early antigen to cytolytic T lymphocytes is selectively prevented by viral genes expressed in the early phase
The regulation of antigen processing and presentation to MHC class I-restricted cytolytic T lymphocytes was studied in cells infected with murine cytomegalovirus. Recognition by cytolytic T lymphocytes of the phosphoprotein pp89, the immunodominant viral antigen expressed in the immediate-early phase of infection, was selectively prevented during the subsequent expression of viral early genes. The surface expression of MHC class I glycoproteins and their capacity to present externally added pp89-derived antigenic peptides were not affected. Because recognition of several other antigens occurred during the early phase, a general failure in processing and presentation was excluded. Since neither rate of synthesis, amount, stability, nor nuclear transport of pp89 was modified, the failure in recognition indicates a selective interference with pp89 antigen processing and presentation
Involvement of Mhc Loci in immune responses that are not Ir-gene-controlled
Twenty-nine randomly chosen, soluble antigens, many of them highly complex, were used to immunize mice of two strains, C3H and B10.RIII. Lymphnode cells from the immunized mice were restimulated in vitro with the priming antigens and the proliferative response of the cells was determined. Both strains were responders to 28 of 29 antigens. Eight antigens were then used to immunize 11 congenic strains carrying different H-2 haplotypes, and the T-cell proliferative responses of these strains were determined. Again, all the strains responded to seven of the eight antigens. These experiments were then repeated, but this time -antibodies specific for the A (AA) or E (EE) molecules were added to the culture to block the in vitro responsiveness. In all but one of the responses, inhibition with both A-specific and E-specific antibodies was observed. The response to one antigen (Blastoinyces) was exceptional in that some strains were nonresponders to this antigen. Furthermore, the response in the responder strains was blocked with A-specific, but not with E-specific, antibodies. The study demonstrates that responses to antigens not controlled by Irr genes nevertheless require participation of class II Mhc molecules. In contrast to Ir gene-controlled responses involving either the A- or the E-molecule controlling loci (but never both), the responses not Ir-controlled involve participation of both A- and E-controlling loci. The lack of Ir-gene control is probably the result of complexity of the responses to multiple determinants. There is thus no principal difference between responses controlled and those not controlled by Ir genes: both types involve the recognition of the antigen, in the context of Mhc molecules
The Democratic Biopolitics of PrEP
PrEP (Pre-Exposure Prophylaxis) is a relatively new drug-based HIV prevention technique and an important means to lower the HIV risk of gay men who are especially vulnerable to HIV. From the perspective of biopolitics, PrEP inscribes itself in a larger trend of medicalization and the rise of pharmapower. This article reconstructs and evaluates contemporary literature on biopolitical theory as it applies to PrEP, by bringing it in a dialogue with a mapping of the political debate on PrEP. As PrEP changes sexual norms and subjectification, for example condom use and its meaning for gay subjectivity, it is highly contested. The article shows that the debate on PrEP can be best described with the concepts ‘sexual-somatic ethics’ and ‘democratic biopolitics’, which I develop based on the biopolitical approach of Nikolas Rose and Paul Rabinow. In contrast, interpretations of PrEP which are following governmentality studies or Italian Theory amount to either farfetched or trivial positions on PrEP, when seen in light of the political debate. Furthermore, the article is a contribution to the scholarship on gay subjectivity, highlighting how homophobia and homonormativity haunts gay sex even in liberal environments, and how PrEP can serve as an entry point for the destigmatization of gay sexuality and transformation of gay subjectivity. ‘Biopolitical democratization’ entails making explicit how medical technology and health care relates to sexual subjectification and ethics, to strengthen the voice of (potential) PrEP users in health politics, and to renegotiate the profit and power of Big Pharma
No cold dust within the supernova remnant Cassiopeia A
A large amount (about three solar masses) of cold (18 K) dust in the
prototypical type II supernova remnant Cassiopeia A was recently reported. It
was concluded that dust production in type II supernovae can explain how the
large quantities (10^8 solar masses) of dust observed in the most distant
quasars could have been produced within only 700 million years after the Big
Bang. Foreground clouds of interstellar material, however, complicate the
interpretation of the earlier submillimetre observations of Cas A. Here we
report far-infrared and molecular line observations that demonstrate that most
of the detected submillimetre emission originates from interstellar dust in a
molecular cloud complex located in the line of sight between the Earth and Cas
A, and is therefore not associated with the remnant. The argument that type II
supernovae produce copious amounts of dust is not supported by the case of Cas
A, which previously appeared to provide the best evidence for this possibility.Comment: 13 pages, 3 figure
The ISO-IRAS Faint Galaxy Survey
The ISO-IRAS Faint Galaxy Survey will obtain comprehensive
space- and ground-based observations of the most distant and luminous galaxies in the IRAS Faint Source Survey. ISO observations are obtained by filling short gaps in the ISO observing schedule with pairs of 11.5μm ISOCAM and 90μm ISOPHOT observations. As of the October 1997 date of this Conference, over 500 sources have been observed by ISO with an ISOCAM detection rate exceeding 803. Ground-based
spectrophotometry confirms that the IIFGS efficiently detects moderateredshift, strong emission line Luminous Infrared Galaxies. Spectrophotometry is currently available for 67 galaxies with 0.07 < z < 0. 7 and
L_(fir) > 10^(11) L_☉. The galaxies are comparable to nearby LIGs, showing HII/Liner excitation; about 10% exhibit strong AGN characteristics. As a part of this survey we will cover over 1.25 square degrees of
sky to an 11.5μm limit of approximately l.0mJy, allowing a sensitive estimate of the 11.5μm logN-logS Relationship. Preliminary ll.5μm source counts suggest substantial evolution in the mid-infrared galaxy population
First Results from the ISO‐IRAS Faint Galaxy Survey
We present the first results from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12 μm ISOCAM and 90 μm ISOPHOT observations. As of 1997 October, over 500 sources have been observed, with an ISOCAM detection rate over 80%, covering over 1.25 deg^2 of sky to an 11.5 μm point-source completeness limit of approximately 1.0 mJy (corresponding to a ~10 σ detection sensitivity). Observations are presented for nine sources detected by ISOPHOT and ISOCAM early in the survey for which we have ground-based G- and I-band images and optical spectroscopy. The ground-based data confirm that the IIFGS strategy efficiently detects moderate-redshift (z = 0.11-0.38 for this small sample) strong emission line galaxies with L_(60 μm) ≳ 10^(11) L_☉; one of our sample has L_(60 μm) > 10^(12) L_☉ (H_0 = 75 km s^(-1) Mpc^(-1), Ω = 1). The infrared-optical spectral energy distributions are comparable to those of nearby luminous infrared galaxies, which span the range from pure starburst (e.g., Arp 220) to infrared QSO (Mrk 231). Two of the systems show signs of strong interaction, and four show active galactic nucleus (AGN)-like excitation; one of the AGNs, F15390+6038, which shows a high excitation Seyfert 2 spectrum, has an unusually warm far- to mid-infrared color and may be an obscured QSO. The IIFGS sample is one of the largest and deepest samples of infrared-luminous galaxies available, promising to be a rich sample for studying infrared-luminous galaxies up to z ~ 1 and for understanding the evolution of infrared galaxies and the star formation rate in the universe
Genetic Determinism and the Innate-Acquired Distinction in Medicine
This article illustrates in which sense genetic determinism is still part of the contemporary interactionist consensus in medicine. Three dimensions of this consensus are discussed: kinds of causes, a continuum of traits ranging from monogenetic diseases to car accidents, and different kinds of determination due to different norms of reaction. On this basis, this article explicates in which sense the interactionist consensus presupposes the innate–acquired distinction. After a descriptive Part 1, Part 2 reviews why the innate–acquired distinction is under attack in contemporary philosophy of biology. Three arguments are then presented to provide a limited and pragmatic defense of the distinction: an epistemic, a conceptual, and a historical argument. If interpreted in a certain manner, and if the pragmatic goals of prevention and treatment (ideally specifying what medicine and health care is all about) are taken into account, then the innate–acquired distinction can be a useful epistemic tool. It can help, first, to understand that genetic determination does not mean fatalism, and, second, to maintain a system of checks and balances in the continuing nature–nurture debates
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