On the deuterium quadrupole coupling constant of H-doped Y---Ba---Cu---O systems

The ²H quadrupole coupling constant e²qQ/h and asymmetry parameter η were measured for deuterium-doped Y₂BaCuO₅ (green phase) where x=0.31 and 0.61 in H_xY₂BaCuO₅ and at temperatures of 180, 300 and 360 K. The values are e²qQ/h = 235 ± 20 kHz and η = 0.05 ± 0.05, independent of x and the temperature. These results, together with previously measured quadrupole coupling constants of other hydrogen-doped Y---Ba---Cu---O compounds, are correlated with IR stretching frequencies of these compounds and support the model that the hydrogen forms an O---H bond.     

Ultra-fast hybrid analog-digital computation with convenient simulation-language software

The succession of digital program steps in typical hybrid analog digital computer simulations is so similar to the stepwise solution of differential-equation systems that well-established continuoussystem-simulation languages, and especially interactive digital simulation systems, can serve as excellent hybridcomputer software with little modification. In particular, the block-diagram-oriented DARE II simulation language can control the ultra-fast LOCUST analog computer to produce unprecendented hybrid execution speed while still permitting quite simple programming. Examples include iterative optimization, computation of hybrid-computer Monte Carlo statistics, and digital two-variable function generation in a hybrid-computer loop.     

A Comparative Study of Several Feature Transformation and Learning Methods for Phoneme Classification

This paper examines the applicability of some learning techniques for speech recognition, more precisely, for the classification of phonemes represented by a particular segment model. The methods compared were the IB1 algorithm (TiMBL), ID3 tree learning (C4.5), oblique tree learning (OC1), artificial neural nets (ANN), and Gaussian mixture modeling (GMM), and, as a reference, a hidden Markov model (HMM) recognizer was also trained on the same corpus. Before feeding them into the learners, the segmental features were additionally transformed using either linear discriminant analysis (LDA), principal component analysis (PCA), or independent component analysis (ICA). Each learner was tested with each transformation in order to find the best combination. Furthermore, we experimented with several feature sets, such as filter-bank energies, mel-frequency cepstral coefficients (MFCC), and gravity centers. We found LDA helped all the learners, in several cases quite considerably. PCA was beneficial only for some of the algorithms, and ICA improved the results quite rarely and was bad for certain learning methods. From the learning viewpoint, ANN was the most effective and attained the same results independently of the transformation applied. GMM behaved worse, which shows the advantages of discriminative over generative learning. TiMBL produced reasonable results; C4.5 and OC1 could not compete, no matter what transformation was tried.     

High-speed block-diagram languages for microprocessors and minicomputers in instrumentation,control and simulation

Block-diagram languages implement instrumentation, control and simulation programs in terms of analog-computer-like block diagrams. Block-operators, which range from simple adders to complete real-time controllers and amplitude-distribution analyzers, are assembly-language macros, ROM subroutines or microprograms. Block-diagram languages are readily accepted by engineers, who need not learn assembly language and can still obtain essentially optimal execution speed on small machines. Block-diagram-programmed minicomputers can beat a CDC 6400 using FORTRAN, and microprocessor execution is much more efficient than PL/M. Machine independent block-diagram programs are sorted and cross-translated by optimizing translators, which eliminate redundant memory references. Efficient block-operator macros, subroutines or microprograms are written once and for all by computer specialists, but new operators can be added at will. This paper discusses an optimal minicomputer translator, an interactive microcomputer system using BASIC to generate and test block-diagram programs, hand-translation for small microprocessor programs and some applications.     

Host immune potentiation of drug responses to a murine mammary adenocarcinoma. II. Effect of melphalan therapy on the host immune system

The role of chemotherapy in influencing tumor-specific immunity to a mouse mammary adenocarcinoma was investigated. By studying different stages of tumor growth we were able to identify several factors important to drug-induced tumor regression: (1) antibody response, (2) delayed hypersensitivity, (3) sensitivity of tumor cells to immune attack and (4) tumor burden. The presence of tumor-specific delayed hypersensitivity and circulating antibody as well as specifically armed monocytes in the tumor mass characterize the T1699 adenocarcinoma. Successful chemotherapy had previously been shown to depend on prior establishment of the above immune responses. Treatment with alkylating agents was marked in all animals by abrogation of a humoral response to the tumor when drug was given early (day 7), and was associated with poor chemotherapeutic results. Later treatment (day 10) was associated with depression of antibody titers only in the minority of animals not responding to drug and prolongation of the delayed hypersensitivity response in all treated animals. Tumors recurring following initial drug-induced regression were marked by lack of delayed hypersensitivity in the host, lack of drug response and suppression of humoral immunity following treatment. Successive passage of cells from these resistant tumors led to decreasing sensitivity to chemotherapy despite established immunity on the part of the host. The selection of tumor cells resistant to immune destruction rather than drug resistance per se appeared to pay a role. Melphalan was thus able to affect both favorably and adversely the immune factors important to drug-induced regression.     

Hirsch-type indices for characterizing networks

Hirsch-type indices are devised for characterizing networks and network elements. Their actual use is demonstrated on scientometric examples, and the potential value of the concept on a practically unlimited range of networks is suggested.     

Two-dimensional characterization of spatially entangled photon pairs

We characterize the entanglement in position and momentum of photon pairs generated in type-II parametric down-conversion. Coincidence maps of the photon positions in the near-field and far-field planes are observed in two transverse dimensions using scanning fiber probes. We estimate the covariance matrix of an effective two-mode system and apply criteria for entanglement based on covariance matrices to certify space–momentum entanglement. The role of higher-order spatial modes for observing spatial entanglement between the two photons is discussed.