816 resultados para Descriptive representation
Resumo:
An algorithm, based on ‘vertex priority values’ has been proposed to uniquely sequence and represent connectivity matrix of chemical structures of cyclic/ acyclic functionalized achiral hydrocarbons and their derivatives. In this method ‘vertex priority values’ have been assigned in terms of atomic weights, subgraph lengths, loops, and heteroatom contents. Subsequently the terminal vertices have been considered upon completing the sequencing of the core vertices. This approach provides a multilayered connectivity graph, which can be put to use in comparing two or more structures or parts thereof for any given purpose. Furthermore the basic vertex connection tables generated here are useful in the computation of characteristic matrices/ topological indices, automorphism groups, and in storing, sorting and retrieving of chemical structures from databases.
Resumo:
In this paper, we investigate how a multilinear model can be used to represent human motion data. Based on technical modes (referring to degrees of freedom and number of frames) and natural modes that typically appear in the context of a motion capture session (referring to actor, style, and repetition), the motion data is encoded in form of a high-order tensor. This tensor is then reduced by using N-mode singular value decomposition. Our experiments show that the reduced model approximates the original motion better then previously introduced PCA-based approaches. Furthermore, we discuss how the tensor representation may be used as a valuable tool for the synthesis of new motions.
Resumo:
BACKGROUND There is weak evidence to support the benefit of periodontal maintenance therapy in preventing tooth loss. In addition, the effects of long-term periodontal treatment on general health are unclear. METHODS Patients who were compliant and partially compliant (15 to 25 years' follow-up) in private practice were observed for oral and systemic health changes. RESULTS A total of 219 patients who were compliant (91 males and 128 females) were observed for 19.1 (range 15 to 25; SD ± 2.8) years. Age at reassessment was 64.6 (range: 39 to 84; SD ± 9.0) years. A total of 145 patients were stable (0 to 3 teeth lost), 54 were downhill (4 to 6 teeth lost), and 21 patients extreme downhill (>6 teeth lost); 16 patients developed hypertension, 13 developed type 2 diabetes, and 15 suffered myocardial infarcts (MIs). A minority developed other systemic diseases. Risk factors for MI included overweight (odds ratio [OR]: 9.04; 95% confidence interval [CI]: 2.9 to 27.8; P = 0.000), family history with cardiovascular disease (OR: 3.10; 95% CI: 1.07 to 8.94; P = 0.029), type 1 diabetes at baseline (P = 0.02), and developing type 2 diabetes (OR: 7.9; 95% CI: 2.09 to 29.65; P = 0.000). A total of 25 patients who were partially compliant (17 males and eight females) were observed for 19 years. This group had a higher proportion of downhill and extreme downhill cases and MI. CONCLUSIONS Patients who left the maintenance program in a periodontal specialist practice in Norway had a higher rate of tooth loss than patients who were compliant. Patients who were compliant with maintenance in a specialist practice in Norway have a similar risk of developing type 2 diabetes as the general population. A rate of 0.0037 MIs per patient per year was recorded for this group. Due to the lack of external data, it is difficult to assess how this compares with patients who have periodontal disease and are untreated.
Resumo:
The African great lakes are of utmost importance for the local economy (fishing), as well as being essential to the survival of the local people. During the past decades, these lakes experienced fast changes in ecosystem structure and functioning, and their future evolution is a major concern. In this study, for the first time a set of one-dimensional lake models are evaluated for Lake Kivu (2.28°S; 28.98°E), East Africa. The unique limnology of this meromictic lake, with the importance of salinity and subsurface springs in a tropical high-altitude climate, presents a worthy challenge to the seven models involved in the Lake Model Intercomparison Project (LakeMIP). Meteorological observations from two automatic weather stations are used to drive the models, whereas a unique dataset, containing over 150 temperature profiles recorded since 2002, is used to assess the model’s performance. Simulations are performed over the freshwater layer only (60 m) and over the average lake depth (240 m), since salinity increases with depth below 60 m in Lake Kivu and some lake models do not account for the influence of salinity upon lake stratification. All models are able to reproduce the mixing seasonality in Lake Kivu, as well as the magnitude and seasonal cycle of the lake enthalpy change. Differences between the models can be ascribed to variations in the treatment of the radiative forcing and the computation of the turbulent heat fluxes. Fluctuations in wind velocity and solar radiation explain inter-annual variability of observed water column temperatures. The good agreement between the deep simulations and the observed meromictic stratification also shows that a subset of models is able to account for the salinity- and geothermal-induced effects upon deep-water stratification. Finally, based on the strengths and weaknesses discerned in this study, an informed choice of a one-dimensional lake model for a given research purpose becomes possible.