13,858 research outputs found
Two Non–*–Isomorphic *–Lie Algebra Structures on sl(2,R) and Their Physical Origins
No full textWe introduce two, Lie algebra isomorphic, real forms of ,
i.e. two real ∗–Lie algebras, denoted respectively and , such that their complexifications ( and are both isomorphic to as Lie algebras. Then we prove that cannot contain a real
∗–Lie sub–algebra ∗–isomorphic to and the same is true exchanging the indexes F and B. The meaning of the indexes B and F is explained in the last section where we show how (resp. can be realized in terms of Bosons (resp. Fermion) operators. These realizations are known in the literature
Flatness of the Commutator Map Over SLn
No full textAbstract Let be any field, and let be a positive integer. If we denote by the commutator morphism over , then is flat over the complement of the center of .Abstract Let be a positive integer. If we denote by the commutator morphism over \xi _{\textrm{SL}_n}\textrm{SL}_n$
The n-Dimensional Quadratic Heisenberg Algebra as a “Non–Commutative” sl(2,C)
No full textWe prove that the commutation relations among the generators
of the quadratic Heisenberg algebra of dimension , look like a kind of non-commutative extension of sl(2,C) (more precisely of its unique 1–
dimensional central extension), denoted and called the complex
n–dimensional quadratic Boson algebra. This non-commutativity has a dif-
ferent nature from the one considered in quantum groups. We prove the
exponentiability of these algebras (for any n) in the Fock representation. We
obtain the group multiplication law, in coordinates of the first and second
kind, for the quadratic Boson group and we show that, in the case of the
adjoint representation, these multiplication laws can be expressed in terms of
a generalization of the Jordan multiplication. We investigate the connections
between these two types of coordinates (disentangling formulas). From this
we deduce a new proof of the expression of the vacuum characteristic function
of homogeneous quadratic boson fields
Resonant indirect Fowler–Nordheim tunneling in Al0.8Ga0.2As barrier
No full textOscillatory current-voltage characteristics of n+-GaAs/semi-insulating Al0.8Ga0.2As/nGaAs heterojunction barriers (400 angstrom thick) grown by molecular beam epitaxy on n+-GaAs (100) substrates are observed at 4 K when the heterostructures are placed under the transverse uniaxial stress along [011] direction (perpendicular to current direction) above 4 kbar. We attribute these oscillations to the resonant indirect Fowler-Nordheim tunneling via [011] oriented transverse X valleys, where the change of wave vector is required for tunneling
Echinax baisha Lu & Li 2023
No full text<i>Echinax baisha</i> Lu & Li, 2023 (白沙NJu) <p>Figs 4–6, 13</p> <p> <i>Echinax baisha</i> Lu & Li, in Lu <i>et al.</i>, 2023: 22, figs 3A–C, 4A–B (♂).</p> <p> <b>Material examined:</b> <b>CHINA:</b> 1♂ (MHUB-ARA-2011-2), <i>Hainan Province</i>, Cangjiang County, Bawang Mountains 30.Ⅴ.2011, leg. F. Zhang. 1♀ (HBUARA#2022-123), <i>Hainan Province,</i> Cangjiang County, Bawang Mountains, Baishi Tan scenic spot (19.131058°N, 109.056163°E, 739 m), 14.VII.2022, leg. L. Zhang.</p> <p> <b>Diagnosis:</b> <i>E. baisha</i> is similar to <i>E. oxyopoides</i> and can be distinguished from it by: 1) the short, sickle-shaped embolus (<i>vs</i> long embolus in <i>E. oxyopoides</i>) (cf. Figs 6A–C, 13E with Figs 9A–C, 13A); 2) the slightly curved terminal part of embolus in retrolateral view (<i>vs</i> curved and C-shaped in <i>E. oxyopoides</i>) (cf. Fig. 13H with Fig. 13B); 3) posteriorly straight copulatory ducts (<i>vs</i> curved in <i>E. oxyopoides</i>) (cf. Fig. 6E with Fig. 9E).</p> <p> <b>Description.</b> <i>Male</i> (Figs 5A–B, 6A–C, 13E–F). For a detailed description see Lu <i>et al.</i>, 2023.</p> <p> <i>Female</i> (Fig. 5C–D). TL 5.83; CL 2.65, CW 2.03; AL 3.23, AW 1.64. Eye sizes and interdistances: AME 0.16, ALE 0.10, PME 0.12, PLE 0.14; AME–AME 0.06, AME–ALE 0.03, ALE–ALE 0.42, PME–PME 0.16, PME– PLE 0.05, PLE–PLE 0.55, ALE–PLE 0.04; MOA 0.24 long, anterior width 0.32, posterior width 0.36. Clypeal height 0.22. LL 0.12, LW 0.31. SL 1.04, SW 0.96. Measurements of legs: I 8.62 (2.60, 0.81, 2.08, 2.15, 0.98), II 8.34 (2.46, 0.82, 2.00, 2.14, 0.92), III 8.18 (2.32, 0.82, 1.88, 2.19, 0.97), IV 10.00 (2.77, 0.85, 2.31, 3.01, 1.06). Carapace creamy, surface smooth; with radial marks, black feathery setae covering markings and dark marginal bands. Endites creamy, apical margin brown. Labium light brown; sternum creamy. Legs creamy, with half ring ventrally. Abdomen oval, creamy, with brown marks and small dorsal scutum.</p> <p>Epigyne as in Fig. 6D–E. Copulatory openings situated laterally in epigastric plate, with arc-shaped edges (Fig. 6D). Copulatory ducts approximately long, longer than receptacle, C-shaped, anterior of copulatory ducts parallel to posterior (Fig. 6D–E). Spermathecae folded, with wrinkles, close to each other.</p> <p> <b>Distribution.</b> China (Hainan).</p>Published as part of <i>Zhang, Lu & Zhang, Feng, 2023, Review of the genus Echinax Deeleman-Reinhold, 2001 from China (Araneae: Corinnidae), pp. 39-56 in Zootaxa 5383 (1)</i> on page 43, DOI: 10.11646/zootaxa.5383.1.3, <a href="http://zenodo.org/record/10301580">http://zenodo.org/record/10301580</a>
CR1 Knops blood group alleles are not associated with severe malaria in the Gambia
No full textThe Knops blood group antigen erythrocyte polymorphisms have been associated with reduced falciparum malaria-based in vitro rosette formation (putative malaria virulence factor). Having previously identified single-nucleotide polymorphisms (SNPs) in the human complement receptor 1 (CR1/CD35) gene underlying the Knops antithetical antigens Sl1/Sl2 and McC(a)/McC(b), we have now performed genotype comparisons to test associations between these two molecular variants and severe malaria in West African children living in the Gambia. While SNPs associated with Sl:2 and McC(b+) were equally distributed among malaria-infected children with severe malaria and control children not infected with malaria parasites, high allele frequencies for Sl 2 (0.800, 1,365/1,706) and McC(b) (0.385, 658/1706) were observed. Further, when compared to the Sl 1/McC(a) allele observed in all populations, the African Sl 2/McC(b) allele appears to have evolved as a result of positive selection (modified Nei-Gojobori test Ka-Ks/s.e.=1.77, P-valu
Comparison of exercise electrocardiography, technetium-99m sestamibi single photon emission computed tomography, and dobutamine and dipyridamole echocardiography for detection of coronary artery disease in hypertensive women
No full textAbstract
To assess the performance of currently used stress tests for the detection of coronary artery disease (CAD) in a series of female hypertensive patients. We performed exercise electrocardiography (ECG), technetium-99m sestamibi (MIBI) single photon emission computed tomography, dobutamine and dipyridamole echocardiography, and coronary angiography in 76 hypertensive women. Of the 76 study patients, 31 (41%) had significant CAD. The sensitivity of exercise ECG (81%), MIBI scanning (90%), and dobutamine echocardiography (87%) was greater than that of dipyridamole echocardiography (61%). This finding resulted from the lower sensitivity of dipyridamole echocardiography in the detection of single-vessel CAD (47% vs 76%, 88%, and 82% for the other 3 methods). In contrast, the sensitivity of the 4 tests was similar in the detection of multivessel CAD. The specificity of exercise ECG (56%) and MIBI scanning (53%) was less than that of dobutamine (82%, both p <0.01) and dipyridamole (91%, both p <0.001) echocardiography. This finding related to the lower specificity of exercise ECG in patients with either left ventricular hypertrophy or ST-T abnormalities at rest compared to the specificity in patients without these disorders (33% vs 89%, p <0.01). A lower MIBI scan specificity was found only in patients with left ventricular hypertrophy (31% vs 66%, p <0.05). The overall accuracy of dobutamine echocardiography reached 84% compared to exercise ECG (66%, p <0.01), MIBI scan (68%, p <0.05), and dipyridamole echocardiography (79%, p <0.05). In conclusion, dobutamine echocardiography yielded satisfactory diagnostic accuracy for identifying CAD in hypertensive women. Although dipyridamole echocardiography had the greatest specificity, it might be limited in detecting mild CAD. Both exercise ECG and MIBI scanning had fare sensitivity; however, our findings limit the usefulness of these 2 tests in unselected patients.
Copyright 2010 Elsevier Inc. All rights reserved
Quantum and its irreducible representations
No full textWe define for real a unital -algebra
quantizing the universal enveloping
-algebra of . The -algebra
is realized as a -subalgebra of the
Drinfeld double of and its dual Hopf -algebra
, generated by the equatorial Podle\'s sphere coideal
-subalgebra of and
its associated orthogonal coideal -subalgebra . We then classify all the irreducible
-representations of .Comment: 22 pages; author accepted manuscrip
Soil Classification Mapping Using a Combination of Semi-Supervised Classification and Stacking Learning (SSC-SL)
No full textIn digital soil mapping, machine learning models have been widely applied. However, the accuracy of machine learning models can be limited by the use of a single model and a small number of soil samples. This study introduces a novel method, semi-supervised classification combined with stacking learning (SSC-SL), to enhance soil classification mapping in hilly and low-mountain areas of Northern Jurong City, Jiangsu Province, China. This study incorporated Gaofen-2 (GF-2) remote sensing imagery along with its associated remote sensing indices, the ALOS Digital Elevation Model (DEM) and their derived topographic factors, and soil parent material data in its modelling process. We first used three base learners, Ranger, Rpart, and XGBoost, to construct the SL model. In addition, we employed the fuzzy c-means clustering algorithm (FCM) to construct a clustering map. To fully leverage the information from a multitude of environmental variables, understand the distribution of data, and enhance the effectiveness of the classification, we selected unlabelled samples near the boundaries of the patches on the clustering map. The SSC-SL model demonstrated superior stability and performance, with optimal accuracy at a 0.9 confidence level, achieving an overall accuracy of 0.77 and a kappa coefficient of 0.73. These metrics exceeded those of the highest performing base learner (Ranger model) by 10.4% and 12.3%, respectively, and they outperformed the least effective base learner (Rpart model) by 27.3% and 32.9%. It notably improves the spatial distribution accuracy of soil types. Key environmental variables influencing soil type distribution include soil parent material (SPM), land use (LU), the multi-resolution valley bottom flatness index (MRVBF), and Elevation (Ele). In conclusion, the SSC-SL model offers a novel and effective approach for enhancing the predictive accuracy of soil classification mapping
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