1,885 research outputs found

    Mixed Statistics on 01-Fillings of Moon Polyominoes

    Get PDF
    We establish a stronger symmetry between the numbers of northeast and southeast chains in the context of 01-fillings of moon polyominoes. Let \M be a moon polyomino with nn rows and mm columns. Consider all the 01-fillings of \M in which every row has at most one 1. We introduce four mixed statistics with respect to a bipartition of rows or columns of \M. More precisely, let S{1,2,...,n}S \subseteq \{1,2,..., n\} and R(S)\mathcal{R}(S) be the union of rows whose indices are in SS. For any filling MM, the top-mixed (resp. bottom-mixed) statistic α(S;M)\alpha(S; M) (resp. β(S;M)\beta(S; M)) is the sum of the number of northeast chains whose top (resp. bottom) cell is in R(S)\mathcal{R}(S), together with the number of southeast chains whose top (resp. bottom) cell is in the complement of R(S)\mathcal{R}(S). Similarly, we define the left-mixed and right-mixed statistics γ(T;M)\gamma(T; M) and δ(T;M)\delta(T; M), where TT is a subset of the column index set {1,2,...,m}\{1,2,..., m\}. Let λ(A;M)\lambda(A; M) be any of these four statistics α(S;M)\alpha(S; M), β(S;M)\beta(S; M), γ(T;M)\gamma(T; M) and δ(T;M)\delta(T; M), we show that the joint distribution of the pair (λ(A;M),λ(Aˉ;M))(\lambda(A; M), \lambda(\bar A; M)) is symmetric and independent of the subsets S,TS, T. In particular, the pair of statistics (λ(A;M),λ(Aˉ;M))(\lambda(A;M), \lambda(\bar A; M)) is equidistributed with (\se(M),\ne(M)), where \se(M) and (M)\ne(M) are the numbers of southeast chains and northeast chains of MM, respectively.Comment: 20 pages, 6 figure

    Predicting speech fluency and naming abilities in aphasic patients

    Get PDF
    There is a need to identify biomarkers that predict degree of chronic speech fluency/language impairment and potential for improvement after stroke. We previously showed that the Arcuate Fasciculus lesion load (AF-LL), a combined variable of lesion site and size, predicted speech fluency in patients with chronic aphasia. In the current study, we compared lesion loads of such a structural map (i.e., AF-LL) with those of a functional map [i.e., the functional gray matter lesion load (fGM-LL)] in their ability to predict speech fluency and naming performance in a large group of patients. The fGM map was constructed from functional brain images acquired during an overt speaking task in a group of healthy elderly controls. The AF map was reconstructed from high-resolution diffusion tensor images also from a group of healthy elderly controls. In addition to these two canonical maps, a combined AF-fGM map was derived from summing fGM and AF maps. Each canonical map was overlaid with individual lesion masks of 50 chronic aphasic patients with varying degrees of impairment in speech production and fluency to calculate a functional and structural lesion load value for each patient, and to regress these values with measures of speech fluency and naming. We found that both AF-LL and fGM-LL independently predicted speech fluency and naming ability; however, AF lesion load explained most of the variance for both measures. The combined AF-fGM lesion load did not have a higher predictability than either AF-LL or fGM-LL alone. Clustering and classification methods confirmed that AF lesion load was best at stratifying patients into severe and non-severe outcome groups with 96% accuracy for speech fluency and 90% accuracy for naming. An AF-LL of greater than 4 cc was the critical threshold that determined poor fluency and naming outcomes, and constitutes the severe outcome group. Thus, surrogate markers of impairments have the potential to predict outcomes and can be used as a stratifier in experimental studies

    Estimation of functional sparsity in nonparametric varying coefficient models for longitudinal data analysis

    Get PDF
    We study the simultaneous domain selection problem for varying coefficient models as a functional regression model for longitudinal data with many covariates. The domain selection problem in functional regression mostly appears under the functional linear regression with scalar response, but there is no direct correspondence to functional response models with many covariates. We reformulate the problem as nonparametric function estimation under the notion of functional sparsity. Sparsity is the recurrent theme that encapsulates interpretability in the face of regression with multiple inputs, and the problem of sparse estimation is well understood in the parametric setting as variable selection. For nonparametric models, interpretability not only concerns the number of covariates involved but also the functional form of the estimates, and so the sparsity consideration is much more complex. To distinguish the types of sparsity in nonparametric models, we call the former global sparsity and the latter local sparsity, which constitute functional sparsity. Most existing methods focus on directly extending the framework of parametric sparsity for linear models to nonparametric function estimation to address one or the other, but not both. We develop a penalized estimation procedure that simultaneously addresses both types of sparsity in a unified framework. We establish asymptotic properties of estimation consistency and sparsistency of the proposed method. Our method is illustrated in simulation study and real data analysis, and is shown to outperform the existing methods in identifying both local sparsity and global sparsity

    In Vitro and ex Vivo Inhibitory Effects of L-and D-Enantiomers of NG Nitro Arginine on Endothelium-Dependent Relaxation of Rat Aorta1

    Get PDF
    ABSTRACT ABBREVIATIONS: Arg, argmnmne;NO, nitric oxide; NMMA, N#{176}-monomethyl-arginmne;NAME, N#{176}-nitro-L-argininemethyl ester; L-NlO, N-iminoethyl-Lomithine; NNA, N#{176}-nitro-arginmne; i.-NM, N#{176}-ammno-L-arginine; ACh, acetyicholine; SNP, sodium nitroprusside; PHE, phenylephrine; MAP, mean arterial pressure; EDRF, endothelium-derived relaxing factor

    What Makes Theatrical Performances Successful in China's Tourism Industry?

    Get PDF
    This study aims to explore the factors affecting the success of a popular tourist product, namely, theatrical performance, within the context of China's tourism industry and develop a model based on previously successful productions. Using qualitative software, 22 Chinese-language articles on theatrical performances are analyzed to generate a list of success factors, classified as internal and external. The internal factors are storyline and performing, market positioning and marketing strategy, investment and financial support, operation and management, performing team, outdoor venue, indoor/outdoor stage supporting facilities, continuous improvement, and production team. The external factors are collaboration between cultural industries and local tourism, government support, privatization, and social and cultural effect. This study also provides suggestions for the future development of theatrical performances in China

    Dirac quasiparticles in the mixed state

    Full text link
    Energies and wave functions are calculated for d-wave quasiparticles in the mixed state using the formalism of Franz and Tesanovic for the low-lying energy levels. The accuracy of the plane-wave expansion is explored by comparing approximate to exact results for a simplified one-dimensional problem, and the convergence of the plane- wave expansion to the two-dimensional case is studied. The results are used to calculate the low-energy tunneling density of states and the low-temperature specific heat, and these theoretical results are compared to semiclassical treatments and to the available data. Implications for the muon spin resonance measurements of vortex core size are also discussed.Comment: 13 pages, 15 figures, RevTeX. References corrected. A factor of 2 in the results has been corrected, and the conclusions have been update

    Factors associated with grade 1 hypertension: implications for hypertension care based on the Dietary Approaches to Stop Hypertension (DASH) in primary care settings

    Get PDF
    Background: A Reference Framework for Hypertension Care was recently developed by Hong Kong government to emphasise the importance of primary care for subjects with high blood pressure (BP). The Dietary Approaches to Stop Hypertension (DASH) interventional regime was recommended for patients aged 40–70 years with grade 1 hypertension (having systolic BP of 140-159 mmHg and/or diastolic BP of 90-99 mmHg). This study explored factors associated with grade 1 hypertension among subjects screened in primary care settings. Methods: The study sample consisted of community dwellers (N = 10,693) enrolled in a primary care programme in which participants overall had similar characteristics when compared to the Hong Kong population census. Invitation phone calls were given by trained researchers to a randomly selected subjects (N = 2,673, [50% of total subjects aged 40–70 years]) between January and June 2013. BP and body mass index (BMI) were measured by trained clinical professionals according to a standard protocol. Interviewer-administered survey questionnaires were used to collect self-report information on socio-demographics, family history, and lifestyle characteristics. Multiple logistic regression analysis was performed to explore factors associated with grade 1 hypertension. Adjusted odds ratios (aORs) were estimated with 95% confidence intervals (CI). Results A total of 679 out of 2,673 subjects agreed to participate in the screening and completed the baseline assessment (100% completion rate), among which, 320 subjects (47.1%, [320/679]) were grade 1 hypertensive. Unhealthy diet (aOR = 2.19, 95%CI 1.04-4.62), irregular meals (aOR = 1.47, 95%CI 1.11-1.95), BMI >27.5 kg/m2 (aOR = 1.87, 95%CI 1.53-2.27), duration of cigarette smoking (aOR = 1.83 per year), increased daily cigarette consumption (aOR = 1.59 per pack [20 cigarettes per pack]), duration of alcohol drinking (aOR = 1.65 per year), and higher frequency of weekly binge drinking (aOR = 1.87 per occasion) were independently associated with grade 1 hypertension. The increase in the number of risk factors combined significantly correlated with higher predicted probability of grade 1 hypertension. Conclusions: Dietary-intake factors were significantly associated with grade 1 hypertension, echoing the recommendation in the Reference Framework on incorporating dietary-related intervention based on the DASH approach for hypertension care in primary care settings. The association between aggregate risk factors and grade 1 hypertension should also be taken into consideration in long-term preventive strategy

    Reinforcement Learning Tutor Better Supported Lower Performers in a Math Task

    Full text link
    Resource limitations make it hard to provide all students with one of the most effective educational interventions: personalized instruction. Reinforcement learning could be a key tool to reduce the development cost and improve the effectiveness of, intelligent tutoring software that aims to provide the right support, at the right time, to a student. Here we illustrate that deep reinforcement learning can be used to provide adaptive pedagogical support to students learning about the concept of volume in a narrative storyline software. Using explainable artificial intelligence tools, we also extracted interpretable insights about the pedagogical policy learned, and we demonstrate that the resulting policy had similar performance in a different student population. Most importantly, in both studies the reinforcement-learning narrative system had the largest benefit for those students with the lowest initial pretest scores, suggesting the opportunity for AI to adapt and provide support for those most in need.Comment: 23 pages. Under revie

    Mixed Statistics on 01-Fillings of Moon Polyominoes

    Full text link
    corecore