44 research outputs found

    Thermal Resonance in Signal Transmission

    Get PDF
    We use temperature tuning to control signal propagation in simple one-dimensional arrays of masses connected by hard anharmonic springs and with no local potentials. In our numerical model a sustained signal is applied at one site of a chain immersed in a thermal environment and the signal-to-noise ratio is measured at each oscillator. We show that raising the temperature can lead to enhanced signal propagation along the chain, resulting in thermal resonance effects akin to the resonance observed in arrays of bistable systems.Comment: To appear in Phys. Rev.

    Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation

    Full text link
    The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas -- particle, nuclear and atomic is reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for EPJ

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

    Get PDF
    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Quantitative structure-activity relationships for the pre-steady-state inhibition of cholesterol esterase by 4-nitrophenyl-N-substituted carbamates

    No full text
    4-Nitrophenyl-N-substituted carbamates (1-6) are the pseudo-substrate inhibitors of porcine pancreatic cholesterol esterase. Thus, the first step of the inhibition (K-i step) is the formation of the enzyme-inhibitor tetrahedral adduct and the second step of the inhibition (k(e)) is the formation of the carbamyl enzyme. The formation of the enzyme-inhibitor tetrahedral adduct is further divided into two steps, the formation of the enzyme-inhibitor complex with the dissociation constant. Ks, at the first step and the formation of the enzyme-inhibitor tetrahedral adduct from the complex at the second step. The two-step mechanism for the formation of the enzyme-inhibitor tetrahedral adduct is confirmed by the pre-steady-state kinetics. The results of quantitative structure-activity relationships for the pre-steady-state inhibitions of cholesterol esterase by carbamates 1-6 indicate that values of -logK(S) and logk(2)/K-2 are correlated with the Taft substituent constant, sigma*, and the rho* values from these correlations are -0.33 and 0.1, respectively. The negative rho* value for the -logK(S)-sigma*-correlation indicates that the first step of the two-step formation of the enzyme-inhibitor tetrahedral adduct (Ks step) is the formation of the positive enzyme-inhibitor complex. The positive rho* value for the logk(2)/k(-2)-sigma*-correlation indicates that the enzyme-inhibitor tetrahedral adduct is more negative than the enzyme-inhibitor complex. Finally, the two-step mechanism for the formation of the enzyme-inhibitor tetrahedral adduct is proposed according to these results. Thus, the partially positive charge is developed at nitrogen of carbamates 1-6 in the enzyme-inhibitor complex probably due to the hydrogen bonding between the lone pair of nitrogen of carbamates 1-6 and the amide hydrogen of the oxyanion hole of the enzyme. The second step of the two-step formation of the enzyme-inhibitor tetrahedral adduct is the nucleophilic attack of the serine of the enzyme to the carbonyl group of carbamates 1-6 in the enzyme-inhibitor complex and develops the negative-charged oxygen in the adduct. (C) 2000 Elsevier Science Ltd. All rights reserved

    A Memory Interleaving and Interlacing Architecture for Deblocking Filter in H.264/AVC

    No full text
    In this paper, a memory interleaving and interlacing VLSI architecture for deblocking filter in H.264/AVC is proposed. Many literatures and the results of the chip implementation show that the memory organization dominates the hardware cost, the throughput rate, and the external memory bandwidth of the deblocking filter. Hence, we also discuss three different levels of the data-reuse scheme for deblocking filter in this paper. In order to increase the throughput, we propose the memory interleaving techniques to arrange data in the on-chip memory and access the data in both horizontal and vertical filters efficiently. We also utilize the hybrid schedule for 2-D processing order and the memory interlacing configuration to reduce the total on-chip memory size and to accomplish the Level B data-reuse scheme. According to proposed memory interleaving organization, memory interlacing configuration and hybrid schedule of the 2-D process order, our architecture only utilizes a half of the traditional memory size to boost the throughput and reduce the bus memory bandwidth(1)

    Molecular epidemiology of Mycobacterium abscessus infections in a subtropical chronic ventilatory setting

    No full text
    The aim of this study was to investigate the high level of pulmonary Mycobacterium abscessus infections and implement a surveillance programme among 43 ventilator-dependent patients, 15 with pulmonary M abscessus infections, in a hospital long-term respiratory care ward (RCW) in central Taiwan M. abscessus isolates were obtained from 35 patients in the RCW of hospital A, 6 patients in the RCWs of another three hospitals (B, C and D), and from 4 water sources in two of the hospitals (A and B). Strains were characterized by methods including hsp65 PCR-RFLP and PFGE. The patients were followed-up by chest X-ray for 1 year All clinical isolates were type I and II, and belonged to ten distinct clusters of PFGE patterns. Five clinical strains in two hospitals belonged to a single cluster, whilst four clinical strains in the other two hospitals belonged to a single unique cluster The strains from hospital A fell into nine clusters and were distinct from the strains isolated from the water supply. Patients infected with type I strains showed a significantly more rapid progression of disease. The number of different strains involved suggested either that there had been a polyclonal outbreak or that a high level of endemic infections was present in the RCW of hospital A This and the lack of homology between the clinical and environmental isolates from hospital A raised the possibility that pulmonary M abscessus infections may have been spread by the movement of patients between RCWs, a routine practice in Taiwan's integrated delivery syste

    Consumption of Groundwater as an Independent Risk Factor of Salmonella Choleraesuis Infection: A Case-Control Study in Taiwan

    No full text
    Infection with Salmonella enterica serovar Choleraesuis (S. Choleraesuis) in humans can be considered as an endemic disease in certain regions of Taiwan, and the number of cases has increased in recent years. The goal of the case-control study discussed in this article was to identify the possible demographic and environmental risk factors associated with S. Choleraesuis infection in Taiwan. During the period of December 2005 to March 2007, the case-control study was conducted in human patients with Salmonella infection from two medical centers. Structured questionnaires were applied to collect information of relevant risk factors after interviewing 13 culture-confirmed S. Choleraesuis cases and 84 controls with other Salmonella serotype infection. After evaluation by univariate and multivariate statistical models, the results suggested that consumption of groundwater could be an independent risk factor associated with S. Choleraesuis in Taiwan. Therefore, appropriate health education needs to be conducted especially in areas where groundwater is used
    corecore