Cashing in on Caching: An Architecture for Time-Bounded Knowledge-Based Problem Solving

Knowledge-based computing, in general, suffers from an inherent open-endedness that precludes its application in time-bounded domains where an answer must be computed within a stipulated time limit. We examine a two-way improvement of the shortcomings: a knowledge representation scheme that provides easy access to relevant knowledge and thereby reduces search time, and a reasoning scheme that is algorithmic in nature and thus makes computational requirements meaningfully estimable.In this work, we offer a cache-based architecture that is capable of both storing knowledge in different formats (e.g. rules, cases), and invoking an appropriate reasoning scheme to fit the available computing time. The cache helps in retrieving the most relevant pieces of knowledge (not only exact matches) required for solving a given problem. This cache relies on a reasoning tactic, knowledge interpolation, that can generate a solution from two near-matches in an algorithmic way, to generate time-bounded solutions. We illustrate the design of such a cache for solving resource allocation problems in the domain of shortwave radio transmission and evaluate its performance in observing imposed temporal bounds.     

Transport and Magnetic AC Losses in Ag/Tl-1223 Tape and the Effect of Mechanical Damage

In this paper we present the results of AC loss measurements on silver clad monocore tapes of Tl-1223 prepared by the powder-in-tube method. Losses arising from an external AC magnetic field are compared with those generated by AC transport currents (self-field losses). Critical current densities are derived from magnetic loss data and compared with those measured by the four point transport method. It was found that mechanically induced stresses (introduced by bending) only have a significant effect on the transport losses, via the critical current degradation. Such changes are not seen in measured magnetic losses, which are independent of mechanical stress, and remain unchanged, at least in the stress range used in our experiment.     

Blocking the PCNA/NKp44 Checkpoint to Stimulate NK Cell Responses to Multiple Myeloma

Simple SummaryMembrane-associated PCNA is expressed on the surface of human MM cell lines and primary MM cells. Mab 14-25-9 interacts with membrane-associated PCNA and blocks its binding to NK-expressed NKp44, thus activating NK function. We showed that mAb 14-25-9 can serve as an immune checkpoint blocker, enhancing the function of NK cells on target human MM cell lines and primary cells.AbstractMultiple Myeloma (MM) is a devastating malignancy that evades immune destruction using multiple mechanisms. The NKp44 receptor interacts with PCNA (Proliferating Cell Nuclear Antigen) and may inhibit NK cells’ functions. Here we studied in vitro the expression and function of PCNA on MM cells. First, we show that PCNA is present on the cell membrane of five out of six MM cell lines, using novel anti-PCNA mAb developed to recognize membrane-associated PCNA. Next, we stained primary bone marrow (BM) mononuclear cells from MM patients and showed significant staining of membrane-associated PCNA in the fraction of CD38⁺CD138⁺ BM cells that contain the MM cells. Importantly, blocking of the membrane PCNA on MM cells enhanced the activity of NK cells, including IFN-γ-secretion and degranulation. Our results highlight the possible blocking of the NKp44-PCNA immune checkpoint by the mAb 14-25-9 antibody to enhance NK cell responses against MM, providing a novel treatment option.     

Tuning in to psychological change: Linguistic markers of psychological traits and emotions over time in popular U.S. song lyrics.

American culture is filled with cultural products. Yet few studies have investigated how changes in cultural products correspond to changes in psychological traits and emotions. The current research fills this gap by testing the hypothesis that one cultural product—word use in popular song lyrics—changes over time in harmony with cultural changes in individualistic traits. Linguistic analyses of the most popular songs from 1980–2007 demonstrated changes in word use that mirror psychological change. Over time, use of words related to self-focus and antisocial behavior increased, whereas words related to other-focus, social interactions, and positive emotion decreased. These findings offer novel evidence regarding the need to investigate how changes in the tangible artifacts of the sociocultural environment can provide a window into understanding cultural changes in psychological processes. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Neurocognitive signs in prodromal Huntington disease.

Objective: PREDICT-HD is a large-scale international study of people with the Huntington disease (HD) CAG-repeat expansion who are not yet diagnosed with HD. The objective of this study was to determine the stage in the HD prodrome at which cognitive differences from CAG-normal controls can be reliably detected. Method: For each of 738 HD CAG-expanded participants, we computed estimated years to clinical diagnosis and probability of diagnosis in 5 years based on age and CAG-repeat expansion number (Langbehn, Brinkman, Falush, Paulsen, & Hayden, 2004). We then stratified the sample into groups: NEAR, estimated to be ≤9 years; MID, between 9 and 15 years; and FAR, ≥15 years. The control sample included 168 CAG-normal participants. Nineteen cognitive tasks were used to assess attention, working memory, psychomotor functions, episodic memory, language, recognition of facial emotion, sensory–perceptual functions, and executive functions. Results: Compared with the controls, the NEAR group showed significantly poorer performance on nearly all of the cognitive tests and the MID group on about half of the cognitive tests (p = .05, Cohen's d NEAR as large as ?1.17, MID as large as ?0.61). One test even revealed significantly poorer performance in the FAR group (Cohen's d = ?0.26). Individual tasks accounted for 0.2% to 9.7% of the variance in estimated proximity to diagnosis. Overall, the cognitive battery accounted for 34% of the variance; in comparison, the Unified Huntington's Disease Rating Scale motor score accounted for 11.7%. Conclusions: Neurocognitive tests are robust clinical indicators of the disease process prior to reaching criteria for motor diagnosis of HD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Non-starch polysaccharides of canola meal: Quantification,digestibility in poultry and potential benefit of dietary enzyme supplementation

The non-starch polysaccharide (NSP) content as determined by gas chromatography (component neutral sugars) and colorimetry (uronic acids) was shown to be 16–22% in ten different samples of defatted canola (low glucosinolate rapeseed) seed. The non-cellulosic components of NSP accounted for 13–16% of the meal and on average consisted of arabinose (33%), xylose (13%), galactose (13%), glucose (5%), mannose (3%), rhamnose (2%), fucose (2%) and uronic acids (30%). Yellow-seeded and brown-seeded samples of canola contained similar contents of total dietary fibre although the composition of the fibre components tended to differ with the former showing a low content of lignin and associated polyphenols and a high content of NSP as compared with the latter type. NDF values tended to be lower for yellow-seeded than for brown-seeded canola due to the relatively high content of NSP in neutral detergent solubles of yellow-seeded canola. An initial balance study with laying hens showed low (<3%) digestibility of the polysaccharide components, and further studies were conducted with a commercial enzyme preparation (SP249, Novo Laboratories Ltd, Lachine, Quebec) to enhance the in-vivo hydrolysis of the NSP fraction of the meal. Laying hens were fed a semipurified diet containing 40% commercial canola meal with and without enzyme (1%). NSP digestibility was increased to 37% by the enzyme supplementation.     

Breakdown probabilities for thin heterostructure avalanche photodiodes

The recurrence theory for the breakdown probability in avalanche photodiodes (APDs) is generalized to heterostructure APDs that may have multiple multiplication layers. The generalization addresses layer-boundary effects such as the initial energy of injected carriers as well as the layer-dependent profile of the dead space in the multiplication region. Reducing the width of the multiplication layer serves to both downshift and sharpen the breakdown probability curve as a function of the applied reverse-bias voltage. In structures where the injected carriers have an initial energy that is comparable to the ionization threshold energy, the transition from linear mode to Geiger-mode is more abrupt than in structures in which such initial energy is negligible. The theory is applied to two recently fabricated Al/sub 0.6/Ga/sub 0.4/As-GaAs heterostructure APDs and to other homostructure thin GaAs APDs and the predictions of the breakdown-voltage thresholds are verified.     

Automatic quantification of changes in bone in serial MR images of joints

Recent innovations in drug therapies have made it highly desirable to obtain sensitive biomarkers of disease progression that can be used to quantify the performance of candidate disease modifying drugs. In order to measure potential image-based biomarkers of disease progression in an experimental model of rheumatoid arthritis (RA), we present two different methods to automatically quantify changes in a bone in in-vivo serial magnetic resonance (MR) images from the model. Both methods are based on rigid and nonrigid image registration to perform the analysis. The first method uses segmentation propagation to delineate a bone from the serial MR images giving a global measure of temporal changes in bone volume. The second method uses rigid body registration to determine intensity change within a bone, and then maps these into a reference coordinate system using nonrigid registration. This gives a local measure of temporal changes in bone lesion volume. We detected significant temporal changes in local bone lesion volume in five out of eight identified candidate bone lesion regions, and significant difference in local bone lesion volume between male and female subjects in three out of eight candidate bone lesion regions. But the global bone volume was found to be fluctuating over time. Finally, we compare our findings with histology of the subjects and the manual segmentation of bone lesions.     

Highly Efficient Rapid Annealing of Thin Polar Polymer Film Ferroelectric Devices at Sub‐Glass Transition Temperature

An unexpected rapid anneal of electrically active defects in an ultrathin (15.5 nm) polar polyimide film at and below glass transition temperature (T_g) is reported. The polar polymer is the gate dielectric of a thin‐film‐transistor. Gate leakage current density (J_g) through the polymer initially increases with temperature, as expected, but decreases rapidly at T_g ? 60 °C. After ≈2 min at T_g, the leakage is reduced by nearly three orders of magnitude. A concomitant observation is that the drain current (I_d)–gate voltage (V_g) hysteresis decreases with temperature, reaching zero at nearly the same temperature at which J_g collapses. As J_g drops further, the drain current hysteresis increases again but in the opposite direction. This combination strongly supports the interpretation of rapid defect annealing.     

A 2-GHz clocked AlGaAs/GaAs HBT byte-slice datapath chip

A byte-slice datapath for exploring multi-chip RISC processor development in AlGaAs-GaAs heterojunction bipolar transistor (HBT) technology has been designed, fabricated and tested. The circuits are implemented using differential current-mode logic (CML) and emitter-coupled logic (ECL) with signal swings of 250 mV. Each datapath chip contains a single slice, including an 8-bit by 32-word single-port register file with a 230-ps read access time, and an 8-bit carry-select adder with a 140-ps select path and a 380-ps ripple-carry path. Each unpackaged die was tested using an at-speed boundary scan test scheme. The register file and adder carry chain are also implemented in a special test chip for accurate performance characterization of these critical circuits