Acute Triangulations of the Cuboctahedral Surface

In this paper we prove that the surface of the cuboctahedron can be triangulated into 8 non-obtuse triangles and 12 acute triangles. Furthermore, we show that both bounds are the best possible.Comment: 16 pages, 8 figures, presented on CGGA201

Rare decay B→XsννˉB \to X_{s} \nu \bar \nu in the two-Higgs-doublet model of type-III

In this paper, we calculated the new physics contribution to theoretically very clean rare decay $B\to X_{s} \nu \bar{\nu}$ in the general two-Higgs-doublet model (model III). Within the considered parameter space, we found that (a) the new physics contribution can provide one to two orders of enhancement to the branching ratio \calb(B\to X_s \nu \bar{\nu}) and can saturate the experimental bound on \calb(B \to X_s \nu \bar{\nu}) in some regions of the parameter space; (b) besides the CLEO data of $B \to X_s \gamma$, the ALEPH upper limit on \calb (B \to X_s \nu \bar{\nu}) also lead to further constraint on the size of the Yukawa coupling $\lambda_{tt}$: $\lambda_{tt}< 6.4$ for $\lambda_{bb}=2.7$ and \mhp=200 GeV.Comment: 10 pages, 3 figures in eps and 1 in ps, Latex fil

Hyperbolic Interaction Model For Hierarchical Multi-Label Classification

Different from the traditional classification tasks which assume mutual exclusion of labels, hierarchical multi-label classification (HMLC) aims to assign multiple labels to every instance with the labels organized under hierarchical relations. Besides the labels, since linguistic ontologies are intrinsic hierarchies, the conceptual relations between words can also form hierarchical structures. Thus it can be a challenge to learn mappings from word hierarchies to label hierarchies. We propose to model the word and label hierarchies by embedding them jointly in the hyperbolic space. The main reason is that the tree-likeness of the hyperbolic space matches the complexity of symbolic data with hierarchical structures. A new Hyperbolic Interaction Model (HyperIM) is designed to learn the label-aware document representations and make predictions for HMLC. Extensive experiments are conducted on three benchmark datasets. The results have demonstrated that the new model can realistically capture the complex data structures and further improve the performance for HMLC comparing with the state-of-the-art methods. To facilitate future research, our code is publicly available

The 2010 spring drought reduced primary productivity in southwestern China

Many parts of the world experience frequent and severe droughts. Summer drought can significantly reduce primary productivity and carbon sequestration capacity. The impacts of spring droughts, however, have received much less attention. A severe and sustained spring drought occurred in southwestern China in 2010. Here we examine the influence of this spring drought on the primary productivity of terrestrial ecosystems using data on climate, vegetation greenness and productivity. We first assess the spatial extent, duration and severity of the drought using precipitation data and the Palmer drought severity index. We then examine the impacts of the drought on terrestrial ecosystems using satellite data for the period 2000–2010. Our results show that the spring drought substantially reduced the enhanced vegetation index (EVI) and gross primary productivity (GPP) during spring 2010 (March–May). Both EVI and GPP also substantially declined in the summer and did not fully recover from the drought stress until August. The drought reduced regional annual GPP and net primary productivity (NPP) in 2010 by 65 and 46 Tg C yr−1, respectively. Both annual GPP and NPP in 2010 were the lowest over the period 2000–2010. The negative effects of the drought on annual primary productivity were partly offset by the remarkably high productivity in August and September caused by the exceptionally wet conditions in late summer and early fall and the farming practices adopted to mitigate drought effects. Our results show that, like summer droughts, spring droughts can also have significant impacts on vegetation productivity and terrestrial carbon cycling

Evaluation of extraction methods for recovery of fatty acids from marine products

The extraction efficiency of Soxhlet, acid hydrolysis and Bligh and Dyer were evaluated by using direct methylation on extracts and residues for calculating the mass balance of fatty acids for eight marine powders (fishmeals, krillmeals, cod filet, salmon filet and herring roe). The results show that Soxhlet gave lowest extracted fatty acid content, especially for the samples which contain a high amount of phospholipid. Acid hydrolysis and Bligh and Dyer extract gave comparable extracted fatty acid contents with direct methylation. The mass balance of fatty acids in extract and residue is close to 100% for the three extraction methods which indicate that fatty acid was not lost during the extraction procedures. The difference of extracted fatty acids is mainly due to the different extracting efficiency. The gravimetric lipid has limited correlation with total fatty acids, especially for Soxhlet. Analyses of the fatty acid profiles showed that the Soxhlet extracts were different from the others. Extracts from the acid hydrolysis and Bligh and Dyer methods had similar fatty acid profiles as the direct methylation method. The precision of fatty acid analysis by direct methylation method for marine powders were also validated. The coefficient of variation was 5.11% for solid samples and 1.21% for liquid sample

Contact characteristics of orthogonal face gear with spur involute pinion

The proposed mechanism of face gear shaping is applied to develop the mathematical model of face gears. Based on the developed mathematical model of the face gear, computer graph of the face gear set is created. Then, the transmission errors of the face gear pairs under various assembly errors are investigated based on the constraints theory of six-degree-of-freedom rigid body motion. The assembly errors are finally obtained by applying the TCA (tooth contact analysis) method. Also, the developed computer simulation programs quantitatively evaluate the influence of assembly errors including offset and angular position errors on the position of contact path and TE (transmission error) in a complete mesh cycle. Besides, the loaded tooth contact characteristics are investigated by using the FEM (finite element method) to study the stick-slip trajectories of the surfaces. The results are illustrated with numerical examples