677 research outputs found
Characterization of a mixed-signal ASIC Communicatons Signal Processor for cordless telephones
This thesis describes the measurement procedures employed to effectively characterize the Lucent Technologies Communications Signal Processor (CSP1009). The Results of these measurements are presented and discussed. This study was conducted on the first prototype to be manufactured. The CSP1009 is the analog baseband integrated circuit chip in a three-chip system designed for use in 900 MHz cordless telephones. Itwas fabricated using a 0.3” CMOS process. The CSP1009 contains several amplifiers including a programmable gain amplifier (PGA), a telephone line driver amplifier and speaker driver amplifier. In addition, it contains a charge pump for use in a phase lock loop circuit, a bandgap reference, an analog to digital converter (ADC) and a digital to analog converter (DAC). The amplifiers were characterized by measuring three quantities; gain, power supply rejection ratio, and total harmonic distortion (THD). The Output current of the charge pump was measured. The voltage of the bandgap reference was measured at different temperatures. The current consumption of the individual modules was also measured. All of these measurements were taken over process variations and over changes in the power supply voltage. The programmable gain amplifiers have gains ranging from OdB to 44dB, PSRR of approximately 50dB, andTHD less than 0.2%. The reference voltage of 1 VDC is derived from the bandgap voltage reference. The charge pump output current is programmable and ranges from 100”A to 1600”A. The total current consumption of the CSP1009, under loaded conditions, was approximately 7mA. Most of the modules on the first prototype of theCSP1009 performed adequately. However, a few anomalies were found. These include aIVDAC offset, low charge pump current, PGA feed-through, and the frequency response of the double sampling circuit rolled off at a lower frequency than expected
'To prepare white excellent...': reconstructions investigating the influence of washing, grinding and decanting of stack-process lead white on pigment composition and particle size
Plasma composition in a sigmoidal anemone active region
Using spectra obtained by the EIS instrument onboard Hinode, we present a
detailed spatially resolved abundance map of an active region (AR)-coronal hole
(CH) complex that covers an area of 359 arcsec x 485 arcsec. The abundance map
provides first ionization potential (FIP) bias levels in various coronal
structures within the large EIS field of view. Overall, FIP bias in the small,
relatively young AR is 2-3. This modest FIP bias is a consequence of the AR
age, its weak heating, and its partial reconnection with the surrounding CH.
Plasma with a coronal composition is concentrated at AR loop footpoints, close
to where fractionation is believed to take place in the chromosphere. In the
AR, we found a moderate positive correlation of FIP bias with nonthermal
velocity and magnetic flux density, both of which are also strongest at the AR
loop footpoints. Pathways of slightly enhanced FIP bias are traced along some
of the loops connecting opposite polarities within the AR. We interpret the
traces of enhanced FIP bias along these loops to be the beginning of
fractionated plasma mixing in the loops. Low FIP bias in a sigmoidal channel
above the AR's main polarity inversion line where ongoing flux cancellation is
taking place, provides new evidence of a bald patch magnetic topology of a
sigmoid/flux rope configfiuration.Comment: For on-line animation, see
http://www.mssl.ucl.ac.uk/~db2/fip_intensity.gif. Accepted by Ap
Recommended from our members
Taphonomy After the Fact: Violence and Ritual in Room 33 at Chaco and Room 178 at Aztec
Chaco Canyonâs Room 33 (excavated by George Pepper) and Aztec Ruins room 178 (excavated by Earl Morris) are recognized for their rich taphonomic context. These two mortuary features reveal a great deal of information about ritualized behavior. Researchers such as Akins and Palkovich have provided partial analyses of the Chaco skeletal material in the 1980s. The reanalysis of those remains considers the Chaco burials in relation to those at Aztec and analyzes their meaning through a thorough analysis of the grave goods, archaeological records, and ethnohistorical documents to provide a better understanding of these elaborate and unique mortuary rooms. Specifically, this study focuses on signatures of identity, biological, cultural, and socioeconomic. Biological identity markers include age, sex, and stature. Cultural identity includes mortuary context, graves goods, and site layout. Socioeconomic identity, which is the hardest to reconstruct is evidenced by the frequency and distribution of trauma related to exposure to violence, changes to anatomy related to unequal amounts of labor, and susceptibility to diseases over time. The result of looking at all these factors is that it is possible to reconstruct identity, such as Burial 3672 in Room 33. This male is especially intriguing because the burial shows evidence of extensive perimortem fractures on the cranium suggesting a violent death, and yet this is a very high status individual based on the stature and isotopic analysis as well as the grave offerings he was interred with. These kinds of taphonomic and mortuary features are explored
Solving Defender-Attacker-Defender Models for Infrastructure Defense
In Operations Research, Computing, and Homeland Defense, R.K. Wood and R.F. Dell, editors, INFORMS, Hanover, MD, pp. 28-49.The article of record as published may be located at http://dx.doi.org10.1287/ics.2011.0047This paper (a) describes a defender-attacker-defender sequential game model (DAD) to plan defenses for an infrastructure system that will enhance that system's resilience against attacks for an intelligent adversary, (b) describes a realistic formulation of DAD for defending a transportation network, (c) develops a decomposition algorithm for solving this instance of DAD and others, and (d) demonstrates the solution of a small transportation-network example. A DAD model generally evaluates system operation through the solution of an optimization model, and the decomposition algorithm developed here requires only that this system-operation model be continuous and convex. For example, our transportation-network example incorporates a congestion model with a (convex) nonlinear objective function and linear constraints
Sex differences in psychosocial predictors of depressive mood upon entry into a cardiac rehabilitation program
Coronal magnetic reconnection driven by CME expansion -- the 2011 June 7 event
Coronal mass ejections (CMEs) erupt and expand in a magnetically structured
solar corona. Various indirect observational pieces of evidence have shown that
the magnetic field of CMEs reconnects with surrounding magnetic fields,
forming, e.g., dimming regions distant from the CME source regions. Analyzing
Solar Dynamics Observatory (SDO) observations of the eruption from AR 11226 on
2011 June 7, we present the first direct evidence of coronal magnetic
reconnection between the fields of two adjacent ARs during a CME. The
observations are presented jointly with a data-constrained numerical
simulation, demonstrating the formation/intensification of current sheets along
a hyperbolic flux tube (HFT) at the interface between the CME and the
neighbouring AR 11227. Reconnection resulted in the formation of new magnetic
connections between the erupting magnetic structure from AR 11226 and the
neighboring active region AR 11227 about 200 Mm from the eruption site. The
onset of reconnection first becomes apparent in the SDO/AIA images when
filament plasma, originally contained within the erupting flux rope, is
re-directed towards remote areas in AR 11227, tracing the change of large-scale
magnetic connectivity. The location of the coronal reconnection region becomes
bright and directly observable at SDO/AIA wavelengths, owing to the presence of
down-flowing cool, dense (10^{10} cm^{-3}) filament plasma in its vicinity. The
high-density plasma around the reconnection region is heated to coronal
temperatures, presumably by slow-mode shocks and Coulomb collisions. These
results provide the first direct observational evidence that CMEs reconnect
with surrounding magnetic structures, leading to a large-scale re-configuration
of the coronal magnetic field.Comment: 12 pages, 12 figure
Roadblock: Improved annotations do not necessarily translate into new functional insights
The advent of cost-effective high-throughput nucleotide sequencing means that information about the transcriptome is accruing at an exponential rate, rapidly refining our understanding of the diversity of gene products. It is important that these findings are readily accessible to the wider scientific community to maximise their impact. However, there are multiple barriers to their efficient dissemination and their translation into functional insights. Here, we outline how the status quo can result in information becoming siloed and/or ambiguous, using the CACNA1C gene, which encodes a voltage-gated calcium channel, as an example. We highlight three areas that pose potential barriers to effective information transfer and offer suggestions as to how these may be addressed: firstly, a lack of clarity about the strength of the evidence for individual transcripts in current annotations; secondly, limitations to the transfer of information between nucleotide and protein databases; thirdly, challenges relating to the nomenclature used for transcriptional events and RNA modifications, both for genomic researchers and the wider scientific community
Logics of Finite Hankel Rank
We discuss the Feferman-Vaught Theorem in the setting of abstract model
theory for finite structures. We look at sum-like and product-like binary
operations on finite structures and their Hankel matrices. We show the
connection between Hankel matrices and the Feferman-Vaught Theorem. The largest
logic known to satisfy a Feferman-Vaught Theorem for product-like operations is
CFOL, first order logic with modular counting quantifiers. For sum-like
operations it is CMSOL, the corresponding monadic second order logic. We
discuss whether there are maximal logics satisfying Feferman-Vaught Theorems
for finite structures.Comment: Appeared in YuriFest 2015, held in honor of Yuri Gurevich's 75th
birthday. The final publication is available at Springer via
http://dx.doi.org/10.1007/978-3-319-23534-9_1
Recognition of host Clr-b by the inhibitory NKR-P1B receptor provides a basis for missing-self recognition
The interaction between natural killer (NK) cell inhibitory receptors and their cognate ligands constitutes a key mechanism by which healthy tissues are protected from NK cell-mediated lysis. However, self-ligand recognition remains poorly understood within the prototypical NKR-P1 receptor family. Here we report the structure of the inhibitory NKR-P1B receptor bound to its cognate host ligand, Clr-b. NKR-P1B and Clr-b interact via a head-to-head docking mode through an interface that includes a large array of polar interactions. NKR-P1B:Clr-b recognition is extremely sensitive to mutations at the heterodimeric interface, with most mutations severely impacting both Clr-b binding and NKR-P1B receptor function to implicate a low affinity interaction. Within the structure, two NKR-P1B:Clr-b complexes are cross-linked by a non-classic NKR-P1B homodimer, and the disruption of homodimer formation abrogates Clr-b recognition. These data provide an insight into a fundamental missing-self recognition system and suggest an avidity-based mechanism underpins NKR-P1B receptor function
- âŠ