The Cryogenic Dark Matter Search (CDMS) experiment employs ultra-cold solid-state detectors to search for rare events resulting from WIMP-nucleus scattering. An innovative detector packaging and ...readout system has been developed to meet the unusual combination of requirements for: low temperature, low radioactivity, low energy threshold, and large channel count. Features include use of materials with low radioactivity such as multi-layer KAPTON laminates for circuit boards; immunity to microphonic noise via a vacuum coaxial wiring design, manufacturability, and modularity.
The detector readout design had to accommodate various electronic components which have to be operated in close proximity to the detector as well maintaining separate individual temperatures (ranging from 600
mK to 150
K) in order to achieve optimal noise performance. The paper will describe the general electrical, thermal, and mechanical designs of the CDMS readout system, as well as presenting the theoretical and measured performance of the detector readout channels.
The pattern of loss of heterozygosity (LOH) on chromosome 17 in human breast cancer is complicated and shows many different regions of loss. In an attempt to narrow down the relevant regions of LOH ...on chromosome 17, we have studied the deletion pattern and its association with clinical parameters in 1280 breast carcinoma-venous blood lymphocyte pairs. In total, 42 different chromosome 17 loci were investigated, and between 25 and 625 cases were analyzed at each locus. The frequency of LOH observed on the p arm was much higher than that observed on the q arm. The opposite effect was observed in 52 ovarian cancer cases investigated, with less LOH on 17p than on 17q. Patterns of loss consistent with interstitial and terminal deletions, as well as loss of either the p or q arm or monosomy 17 were observed. To determine whether loss at particular loci may be associated with biological features of breast tumors, clinical data including age of onset, family history of breast cancer, tumor histopathology, tumor size, estrogen receptor (ER) status, and occurrence of lymph node or distant metastases were collected for each case. Overall, large-sized, ER-negative, lymph node-positive ductal tumors showed the highest frequencies of LOH, with ER-negative and ductal tumors showing LOH for markers along the majority of the chromosome. Eight regions of chromosome 17 appear to be associated with human breast cancer, two on 17p and six on 17q. These regions were not necessarily in the areas exhibiting the highest frequencies of LOH but were defined by interstitial and terminal deletions in multiple independent cases. Seven of these regions showed statistically significant differences in LOH associated with clinical parameters. These data strongly suggest that loci on chromosome 17 may determine aspects of tumor presentation and disease behavior in human breast cancer and pinpoint candidate tumor suppressor gene loci.
Tumor necrosis factor (TNF) exerts its biologic activity via two distinct membrane receptors, TNF receptor type 1 (p55TNFR) and TNF receptor type 2 (p75TNFR). Whereas the p55TNFR gene is rather ...constitutively expressed, transcription of p75TNFR is strongly modulated by a number of stimulatory agents. Experimental evidence suggested the involvement of p75TNFR in endothelial cell activation. Therefore, we have tested the transcriptional activity of p75TNFR under conditions of hypoxia and reoxygenation. Northern blot analysis revealed that p75TNFR mRNA is upregulated in NIH3T3 cells under hypoxia and reoxygenation. This observation directly originates from transcriptional activation of the p75TNFR gene, as shown by reporter gene analysis. Cotransfection experiments clearly showed that the transcriptional induction of the p75TNFR gene is independent of the hypoxia-induced factors, HIF-1alpha and HIF-2alpha. Using deletion mutants of the 5'-flanking region of the p75TNFR gene, we were able to identify a putative DNA binding site for the transcription factor nuclear factor-interleukin-6 (NF-IL-6) to be responsible for the transcriptional upregulation of the p75TNFR gene under conditions of hypoxia and reoxygenation.
The Radio Frequency Spectrometer (RFS) is a two‐channel digital receiver and spectrometer, which will make remote sensing observations of radio waves and in situ measurements of electrostatic and ...electromagnetic fluctuations in the solar wind. A part of the FIELDS suite for Solar Probe Plus (SPP), the RFS is optimized for measurements in the inner heliosphere, where solar radio bursts are more intense and the plasma frequency is higher compared to previous measurements at distances of 1 AU or greater. The inputs to the RFS receiver are the four electric antennas mounted near the front of the SPP spacecraft and a single axis of the SPP search coil magnetometer (SCM). Each RFS channel selects a monopole or dipole antenna input, or the SCM input, via multiplexers. The primary data products from the RFS are autospectra and cross spectra from the selected inputs. The spectra are calculated using a polyphase filter bank, which enables the measurement of low amplitude signals of interest in the presence of high‐amplitude narrowband noise generated by spacecraft systems. We discuss the science signals of interest driving the RFS measurement objectives, describe the RFS analog design and digital signal processing, and show examples of current performance.
Plain Language Summary
Solar Probe Plus (SPP) is a NASA mission which will travel much closer to the Sun than any previous spacecraft. The FIELDS experiment on SPP is composed of sensors (antennas and magnetometers) and receivers which will measure the electric and magnetic fields in this unexplored region. This paper describes the Radio Frequency Spectrometer (RFS), a receiver which will measure radio waves up to 19.2 MHz. We describe the types of radio signal sources present in interplanetary space close to the Sun, show how the design of the RFS makes it possible to measure these sources, and demonstrate the current performance of the receiver.
Key Points
The RFS is a newly designed receiver and spectrometer for Solar Probe Plus
The RFS provides the FIELDS suite with high‐frequency measurements of radio bursts and quasi‐thermal noise
The RFS is optimized for flexible operations and minimal use of resources
Los Alamos National Laboratory has a long history of developing and fielding high explosive pulsed power (HEPP) components and systems. In recent years, the Ranchero flux compression generator (FCG ...or generator) has been modified for improved high current performance, and a new helical flux compression generator (HFCG), the MK-X, has been designed to provide higher initial flux for Ranchero FCGs than can be achieved with the existing capacitor bank at Los Alamos HEPP test facilities. Integrating these two FCGs into a system is the focus of current development, and the first full system test has been performed. The system consists of a MK-X coupled efficiently to an R43S6 FCG with an exploratory pulse forming network (PFN) connecting the FCGs to the load. "R43S6" has become the shorthand designation for a Ranchero module with a 43 cm coaxial section and a Swooped output using a 6 inch diameter coaxial high explosive charge. The goal is to deliver ~50 MA to physics loads on microsecond time scales, and the following material illuminates the design philosophy and summarizes the outcome of the discussions and tests. Analysis of test data is still in progress, and a preliminary synopsis of results is given. Details of our PFN work are given by Gianakon 1 in this conference.
A Neural Basis for General Intelligence Duncan, John; Seitz, Rüdiger J.; Kolodny, Jonathan ...
Science (American Association for the Advancement of Science),
07/2000, Letnik:
289, Številka:
5478
Journal Article
Recenzirano
Odprti dostop
Universal positive correlations between different cognitive tests motivate the concept of "general intelligence" or Spearman's g. Here the neural basis for g is investigated by means of positron ...emission tomography. Spatial, verbal, and perceptuo-motor tasks with high-g involvement are compared with matched low-g control tasks. In contrast to the common view that g reflects a broad sample of major cognitive functions, high-g tasks do not show diffuse recruitment of multiple brain regions. Instead they are associated with selective recruitment of lateral frontal cortex in one or both hemispheres. Despite very different task content in the three high-g-low-g contrasts, lateral frontal recruitment is markedly similar in each case. Many previous experiments have shown these same frontal regions to be recruited by a broad range of different cognitive demands. The results suggest that "general intelligence" derives from a specific frontal system important in the control of diverse forms of behavior.
We present the completed KMOS3D survey, an integral field spectroscopic survey of 739 \(\mathrm{log}({M}_{\star }/{M}_{\odot })\gt 9\) galaxies at 0.6 < z < 2.7 using the K-band Multi Object ...Spectrograph (KMOS) at the Very Large Telescope. The KMOS3D survey provides a population-wide census of kinematics, star formation, outflows, and nebular gas conditions both on and off the star-forming galaxy main sequence through the spatially resolved and integrated properties of Hα, N ii, and S ii emission lines. We detect Hα emission for 91% of galaxies on the main sequence of star formation and 79% overall. The depth of the survey has allowed us to detect galaxies with star formation rates below 1 M ⊙ yr−1, as well as to resolve 81% of detected galaxies with ≥3 resolution elements along the kinematic major axis. The detection fraction of Hα is a strong function of both color and offset from the main sequence, with the detected and nondetected samples exhibiting different spectral energy distribution shapes. Comparison of Hα and UV+IR star formation rates reveal that dust attenuation corrections may be underestimated by 0.5 dex at the highest masses (\(\mathrm{log}({M}_{\star }/{M}_{\odot })\gt 10.5\)). We confirm our first year results of a high rotation-dominated fraction (monotonic velocity gradient and v rot/\({\sigma }_{0}\gt \sqrt{3.36}\)) of 77% for the full KMOS3D sample. The rotation-dominated fraction is a function of both stellar mass and redshift, with the strongest evolution measured over the redshift range of the survey for galaxies with \(\mathrm{log}({M}_{\star }/{M}_{\odot })\lt 10.5\). With this paper, we include a final data release of all 739 observed objects (http://www.mpe.mpg.de/ir/KMOS3D).
We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23 million Upsilon(4S)-->B-anti-B decays ...collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events where one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta=0.34 +/- 0.20 (stat) +/- 0.05 (syst).
Piwi-interacting RNAs (piRNAs) silence transposons in animal germ cells. piRNAs are thought to derive from long transcripts spanning transposon-rich genomic loci and to direct an autoamplification ...loop in which an antisense piRNA, bound to Aubergine or Piwi protein, triggers production of a sense piRNA bound to the PIWI protein Argonaute3 (Ago3). In turn, the new piRNA is envisioned to produce a second antisense piRNA. Here, we describe strong loss-of-function mutations in
ago3, allowing a direct genetic test of this model. We find that Ago3 acts to amplify piRNA pools and to enforce on them an antisense bias, increasing the number of piRNAs that can act to silence transposons. We also detect a second, Ago3-independent piRNA pathway centered on Piwi. Transposons targeted by this second pathway often reside in the
flamenco locus, which is expressed in somatic ovarian follicle cells, suggesting a role for piRNAs beyond the germline.
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