Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ～MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.     

Interleukin‐4‐Clicked Surfaces Drive M2 Macrophage Polarization

Driving macrophage (M?) polarization into the M2 phenotype provides potential against inflammatory diseases. Interleukin‐4 (IL‐4) promotes polarization into the M2‐M? phenotype, but its systemic use is constrained by dose‐limiting toxicity. Consequently, we developed IL‐4‐decorated surfaces aiming at sustained and localized activity. IL‐4 muteins were generated by genetic code expansion; Lys42 was replaced by unnatural amino acids (uAAs). Both muteins showed cell‐stimulation ability and binding affinity to IL4Rα similar to those of wt‐IL‐4. Copper‐catalyzed (CuAAC) and copper‐free strain‐promoted (SPAAC) 1,3‐dipolar azide–alkyne cycloadditions were used to site‐selectively anchor IL‐4 to agarose surfaces. These surfaces had sustained IL‐4 activity, as demonstrated by TF‐1 cell proliferation and M2, but not M1, polarization of M‐CSF‐generated human M?. The approach provides a blueprint for the engineering of cytokine‐activated surfaces profiled for sustained and spatially controlled activity.     

Individual differences in information-processing rate and amount: Implications for group differences in response latency.

Research on group differences in response latency often has as its goal the detection of Group ?×? Treatment interactions. However, accumulating evidence suggests that response latencies for different groups are often linearly related, leading to an increased likelihood of finding spurious overadditive interactions in which the slower group produces a larger treatment effect. The authors propose a rate-amount model that predicts linear relationships between individuals and that includes global processing parameters based on large-scale group differences in information processing. These global processing parameters may be used to linearly transform response latencies from different individuals to a common information-processing scale so that small-scale group differences in information processing may be isolated. The authors recommend linear regression and z-score transformations that may be used to augment traditional analyses of raw response latencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High Fluence Ion Irradiation of Thin Fullertte Films

Abstract

Thin fullerite films - partly covered with a thin Au layer -have been irradiated with 100 keV Arⁿ⁺ (n = 1, 6, and 12), 250 keV N⁺, and 30 keV Au⁺ ions up to high fluences, and subsequently analyzed by profilometry, Rutherford Backscattering Spectrometry (RBS), and Atomic Force Microscopy (AFM). Depending on the system, either an increase or a decrease of the film thickness after the irradiations was found, and the probing RBS α particles suffered sometimes an enhanced, and sometimes a reduced energy loss upon passage through the films. The comparison of profilometry and RBS results on uncovered and covered samples allows us to separate the different effects which influence the behavior of high-fluence irradiated fullerite samples clearly from each other. Such effects might be the incorporation of the projectile ions, density changes, phase changes, sputtering, and transport of neighbored unirradiated matter into the irradiated zone.

It is remarkable that ion irradiation of fullerite can lead as well to a densified material, with densities of about 2.1 g-cm^?3, as to a foam-like carbonaceous material with a density around 0.35 g-cm^?3 - depending on the type of projectile and its range. The latter case appears to be characteristic for high-fluence heavy noble gas implantation into fullerite. Fullerite sputtering was reconfirmed to decrease inversely with the fluence.     

XFEM modeling and homogenization of magnetoactive composites

This paper addresses the application of the extended finite element method (XFEM) to the modeling of two-dimensional coupled magneto-mechanical field problems. Continuum formulations of the stationary magnetic and the coupled magneto-mechanical boundary problem are outlined, and the corresponding weak forms are derived. The XFEM is applied to generate numerical models of a representative volume element, characterizing a magnetoactive composite material. Weak discontinuities occurring at material interfaces are modeled numerically by an enriched approximation of the primary field variables. In order to reduce the complexity of the representation of curved interfaces, an element local approach is proposed which allows an automated computation of the level set values. The composite’s effective behavior and its coupled magneto-mechanical response are computed numerically by a homogenization procedure. The scale transition process is based on the energy equivalence condition, which is satisfied by using periodic boundary conditions.     

Neuartige Sandwichverbunde – Herstellung,Umformverhalten, Fügen und Korrosionsverhalten

New Sandwichmaterials – Production, Forming, Joining and Corrosion Behaviour New sandwich structures with sheet metal of CrNi‐steel and core layer made of polypropylene were examined with regard to the processing and corrosion characteristics. Practicable solutions for bonding sandwich structures are represented with selected examples of bonding variants. Joining of the sandwich structures was carried out by laser welding and in form of hybrid junctions by adhesion and welding. It has to be taken into account that construction units are transformed before joining. The joint if possible does not lie in the transforming range if it is joined first. In the 3 roll bending test tubing elements up to a process‐bound diameter of 70 mm were manufactured. As expected the corrosion resistance is affected negatively by the oxide scale due to welding at the fusion lines. The characteristics of the basic material were regained after removing the oxide scale. A sensitization to intergranular corrosion was not detected. With correct subsequent treatment the finished sandwich structures are sufficient for the appropriate requirements.     

On-the-fly verification and optimization of DTA-properties for large Markov chains

We consider continuous-time Markov chains (CTMC) with very large or infinite state spaces which are, for instance, used to model biological processes or to evaluate the performance of computer and communication networks. We propose a numerical integration algorithm to approximate the probability that a process conforms to a specification that belongs to a subclass of deterministic timed automata (DTAs). We combat the state space explosion problem by using a dynamic state space that contains only the most relevant states. In this way we avoid an explicit construction of the state-transition graph of the composition of the DTA and the CTMC. We also show how to maximize the probability of acceptance of the DTA for parametric CTMCs and substantiate the usefulness of our approach with experimental results from biological case studies.     

Visual Word Recognition of Single-Syllable Words.

Speeded visual word naming and lexical decision performance are reported for 2,428 words for young adults and healthy older adults. Hierarchical regression techniques were used to investigate the unique predictive variance of phonological features in the onsets, lexical variables (e.g., measures of consistency, frequency, familiarity, neighborhood size, and length), and semantic variables (e.g.. imageahility and semantic connectivity). The influence of most variables was highly task dependent, with the results shedding light on recent empirical controversies in the available word recognition literature. Semantic-level variables accounted for unique variance in both speeded naming and lexical decision performance, level with the latter task producing the largest semantic-level effects. Discussion focuses on the utility of large-scale regression studies in providing a complementary approach to the standard factorial designs to investigate visual word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical competition and phonological encoding in young and older speakers.

The influence of age on word retrieval was investigated with a speeded picture naming study. Five hundred forty-one pictures were presented to young and older adults, and the influence of name agreement and name frequency was analyzed by multiple regression. The results showed that both name agreement and name frequency are significant predictors of picture naming performance in young and older adults. The results also suggest that older adults are more strongly influenced by name agreement than are young adults. These results indicate that competition during lexical selection may be a particularly age-sensitive stage in language production. (PsycINFO Database Record (c) 2010 APA, all rights reserved)