62,145 research outputs found
q-Differential equations for q-classical polynomials and q-Jacobi-Stirling numbers
No full textWe introduce, characterise and provide a combinatorial interpretation for the so-called q-Jacobi–Stirling numbers.
This study is motivated by their key role in the (reciprocal) expansion of any power of a second order
q-differential operator having the q-classical polynomials as eigenfunctions in terms of other even order operators,
which we explicitly construct in this work. The results here obtained can be viewed as the q-version of
those given by Everitt et al. and by the first author, whilst the combinatorics of this new set of numbers is a
q-version of the Jacobi–Stirling numbers given by Gelineau and the second author
Ascopolyporus tibetensis F. M. Yu, Q. Zhao & T. Luangharn
No full text<i>Ascopolyporus tibetensis</i> F.M. Yu, Q. Zhao & T. Luangharn <p> <b>Host:</b> On the living stem of bamboo</p> <p> <b>Distribution:</b> China (Tibet)</p>Published as part of <i>Yu, Feng-Ming, Wei, De-Ping, Zhao, Qi, Tang, Song-Ming & Luangharn, Thatsanee, 2023, Ascopolyporus tibetensis (Cordycipitaceae, Hypocreales): a new species from Tibet, China, pp. 88-98 in Phytotaxa 592 (2)</i> on page 95, DOI: 10.11646/phytotaxa.592.2.2, <a href="http://zenodo.org/record/7840405">http://zenodo.org/record/7840405</a>
Tuber sinomacrosporum S. P. Wan, & F. Q. Yu 2023, sp. nov.
No full textTuber sinomacrosporum S. P. Wan, & F. Q. Yu, sp. nov. (FIGURE 2) MycoBank: 846502 Typification: CHINA. Yunnan Province, Dali City (25° 38′ N , 100° 68′ E), in humic soil under a pure Pinus forest, at about 2090 m, 26 December 2020, wsp1043-8, YNAU016 (GenBank ITS number = OK625303). Diagnosis: Tuber sinomacrosporum is characterized by the brownish-red ascoma, mostly 1(2)-spored asci, large and ellipsoid ascospores. Etymology: referring to a Chinese species have large spores. Description: Ascoma 2.2 × 1.35 cm in diam, oval-shaped or irregular, light brown, partial brown to brownishred when fresh, becoming brownish-red when dried, surface partially covered with yellow tomentose. Odor pleasant. Peridium 108.0–148.0 μm thick, one layer, prosenchymatous, composed of yellowish to transparent cells and interwoven hyphae, cells (1.0–)2.2–5.7(–7.8) × (1.0–)1.7–4.5(–5.4) μm, hyphae 1.3–2.8 μm in diam. Gleba solid, blackish at maturity, marbled with different whitish to greyish veins continuous with the peridium; composed of hyaline, interwoven, thin-walled hyphae, 0.7–2.4 μm broad at the septa, the cells subglobose to globose, 1.1–7.3(– 10.5) × 0.9–5.7(–8.6) μm. Asci 114.0–143.0(–158.0) × 86.0–117.0(–124.0) μm, ellipsoid, rarely pyriform or irregular, hyaline, sessile or with a short or tall stalk 7.5–49.0 μm, 1-spored, rarely 2-spored. Ascospores ellipsoid, sometimes oblong elliptical and broadly ellipsoid, hyaline when young, becoming brownish-red to brown at maturity; excluding alveolar ornamentation, in 1-spored asci (80.0–)89.0–105.0(–109.0) × (55.0–)61.0–76.0(–78.0) μm (Q = 1.32–1.53, Q m = 1.43 ± 0.08) (n = 120), in 2-spored (51.0–)55.0–78.0(–84.0) × (32.0–)37.0–55.0(–57.0) μm (Q = 1.25–1.65, Q m = 1.4 ± 0.16) (n = 30). Ornamented with alveolate reticulum, 2–6 μm deep, constituted of irregularly polygonal meshes, reticulum with 3–7 meshes along the spore length and 3–7 across. Distribution and habitat: Hypogeous, in soil under pure stand of Pinus forest in Yunnan Province, China. Known only from China.Published as part of Wan, Shan-Ping, Liu, Wei, Cui, Meng-Jin, Wang, Rui, Wang, Yu-Yun, Liu, Mei-Ju, Wang, Rui- Xue, Yu, Cheng-Jin & Yu, Fu-Qiang, 2023, Morphological and molecular evidence support a new truffle, Tuber sinomacrosporum, in Macrosporum group, pp. 283-291 in Phytotaxa 591 (4) on pages 286-288, DOI: 10.11646/phytotaxa.591.4.5, http://zenodo.org/record/783557
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Network Q
No full textA press release from Network Q announcing that they will begin featuring Brian McNaught, a gay columnist and author, for a monthly segment
Polinomios ortogonales respecto a medidas q-discretas. Aplicaciones
No full textLa Teoría de funciones especiales y, más concretamente, la Teoría de polinomios ortogonales constituyen unas de las fuentes más apreciadas por la cantidad de aplicaciones tanto en la matemática y como en la física con la que éstas aparecen relacionadas. Entre ellas se encuentran la teoría de números, el análisis numérico, la teoría de operadores, la teoría de representación de grupos y la mecánica cuántica, por citar algunas. En esta memoria se han desarrollado, dentro de la variedad de problemas que se pueden encontrar relacionados con dichas teorías, los siguientes problemas que están íntimamente vinculados con algunas de las áreas antes mencionadas: 1) Estudio del problema de factorización de la ecuación de Nikiforov y Uvarov y su aplicación a la construcción de distintos modelos de q- osciladores armónicos y sus correspondientes álgebras dinámicas. 2) Estudio y desarrollo de distintos aspectos de la teoría de polinomios ortogonales clásicos y semiclásicos en redes no uniformes. En particular el estudio de ciertas propiedades que permitan caracterizar a dichas familias. 3) Finalmente se estudian algunos ejemplos concretos de q-polinomios de especial interés como los q-polinomios de Racah y los q-polinomios de tipo Kral
Network Q
No full textA press release from Network Q announcing that they will begin featuring Brian McNaught, a gay columnist and author, for a monthly segment
Tobin's Q and Financial Policy
No full textRecent research in macroeconomics has emphasized the importance of linking the financial and real sectors and the need for working with optimizing models. Tobin’s Q model of investment would appear to provide a framework that can satisfy these two criteria. In contrast to the original presentation of the Q model, the formal development has not recognized that the firm actively participates in a number of financial markets; in this broader context, we show that Q is likely to be an uninformative and possibly misleading signal for investment expenditures . We then endeavor to turn this negative theoretical result to positive advantage in resolving a number of empirical problems with Q models, but the modifications dictated by the theory receive little support from the data.
Thermometry based on Whispering Gallery Mode resonators
No full textWhispering gallery (WG) mode resonators were studied since 1980s for precision clock oscillators and for cavity quantum electrodynamics studies. They are a kind of stable, high Q, microwave resonators where a symmetric dielectric medium, such as a cylinder or a disk, is suspended in the centre of a metal cavity. A coaxial cable or a waveguide are used to couple the EM field in the microwave region and thus to excite the system resonant frequencies. WG modes are resonant modes of higher-order azimuthal number (m) having most of the EM energy concentrated on the dielectric surface. Within the temperature range of -196 °C to 500 °C the most commonly used industrial thermometer is platinum resistance thermometer (PRT) with the uncertainties of 10 mK. The PRT offers high accuracy, low drift, a wide operating range; however, it is very sensitive to mechanical shock in handing and shipping. Besides, an AC resistance bridge which is typically required as a readout device for PRT is very expensive. Accordingly, there is a great need for a stability-improved, resistant to mechanical shock, potential lower uncertainty and cost-effective industrial thermometer. WGMR thermometer (WGMRT) is a new kind of thermometer which offers greater vibration immunity, improved stability, smaller uncertainty in temperature measurement and potential lower cost than platinum resistance thermometry. An innovative sapphire whispering gallery thermometer (SWGT) was first explored at the National Institute of Standards and Technology (NIST) in 2007 by Strouse [1] with the uncertainty less than 10 mK. Five WGMs with nominal resonant frequencies ranging from 14.4 GHz to 19.1 GHz and with Q-factors, respectively, ranging from 20,000 to 90,000 were measured within the temperature range of 0 °C to 100 °C. The accuracies of his WGMTs were in the range of ± 0.02 °C and ice point repeatability was better than 2 mK. The thesis reports the tests performed on several WGMR thermometers which have different shapes of crystals to evaluate their stability, resolution and repeatability in the temperature range of -40 °C to 85°C. Thermal cycle experimental results IV showed a Q in excess of 100000 for the mode with the highest azimuthal number, making it possible to achieve a potential temperature resolution of 0.1 mK. Besides, different specimens of crystals with the same nominal specification and reassemble for the same specimen were both tested to check the reproducibility of the thermometer. The birefringence of the sapphire was also studied to make an innovative thermometer. The ratios of two doublet frequencies are sensitive to the temperature-dependent birefringence of the crystal and relatively insensitive to surface contamination and changes in the shape of the cavity. Besides, it can have an external shape that closely approximates the shape of conventional platinum resistance thermometer
Codonopsis atriplicifolia Y. YU & Q. Wang, MW 2021, sp. nov.
No full text<i>Codonopsis atriplicifolia</i> Y. Yu & Q. Wang, sp. nov. Figs. 2A–F <p> <b>Type</b>:— CHINA. Sichuan, Baiyu, Chola mountains, rocky slope, 3300 m, 19 Jul 2020, <i>Y. Yu et al. DS02</i> (holotype: SZ barcode 02042692!; isotypes: SZ barcodes 02042693!, 02042694!, 02042695!).</p> <p>Roots carrot-shaped, slender, 5–20 cm long, 0.3–0.5 cm in diameter. Stems erect, 50–120 cm tall, simple or branched below, sparsely pubescent to subglabrous. Leaves subrosulate, alternate; petiole 0.5–4 cm long, subglabrous; leaf blade linear-lanceolate, 3–15 cm long, 0.5–1.5 cm broad, adaxially green, sparsely hispidulous, abaxially gray-green, sparsely hispid along veins, base cuneate, margin subentire to pinnatipartite, apex obtuse. Flowers often solitary and terminal on main stem and branches. Calyx tube adnate to whole hypanthium, semiglobose, 10-ribbed, subglabrous; calyx lobes narrowly deltoid, 0.4–0.8 cm long, 0.2–0.3 mm broad, glabrous, margin entire, sometimes sparsely serrate, apex acute; sinus between lobes broad and truncate. Corolla broadly campanulate, 1–2 cm long, 1.5–2 cm wide, lobed to near one third, red-purple with dark purple veins, and white on apex of corolla lobe, glabrous on both sides with sparsely hispidulous margin. Stamens glabrous; filaments 0.3–0.5 cm long, slightly dilated at base; anthers ca. 3 mm long. Capsule semiglobose below, conical above. Seeds unknown.</p> <p> <b>Etymology</b>:—From Latin, <i>atriplici-</i> ‘ <i>Atriplex</i> ’ + <i>folia</i> ‘leaf’. Meaning the species with leaves like those from the species of <i>Atriplex</i> Linnaeus (1753: 1052), which is a genus that belongs to the family Amaranthaceae. In order to facilitate communication among local scholars, we suggest a Chinese name: <b>bīnlíyè dǎngshēn</b> (滨※叶党参).</p> <p> <b>Phenology</b>:—Flowering from June to August; fruiting in September and October.</p> <p> <b>Habitat</b>:—Rocky slopes at an altitude of ca. 3300 m.</p> <p> <b>Distribution</b>:—Endemic to western Sichuan, China.</p>Published as part of <i>Zhou, Yu-Yang, Si, Yun-Hao, Zhang, Zhen, Wang, Qiang & Yu, Yan, 2021, Codonopsis atriplicifolia (Campanulaceae), a new species from western Sichuan, China, pp. 197-204 in Phytotaxa 512 (3)</i> on page 199, DOI: 10.11646/phytotaxa.512.3.7, <a href="http://zenodo.org/record/5305521">http://zenodo.org/record/5305521</a>
Interfacing q-AQUA with a Polarizable Force Field: The Best of Both Worlds
No full textPolarizable force fields are pervasive in the fieldsof computationalchemistry and biochemistry; however, their empirical or semiempiricalnature gives them both weaknesses and strengths. Here, we have developeda hybrid water potential, named q-AQUA-pol, by combining our recent ab initio q-AQUA potential with the TTM3-F water potential.The new potential demonstrates unprecedented accuracy ranging fromgas-phase clusters, e.g., the eight low-lying isomers of the waterhexamer, to the condensed phase, e.g., radial distribution functions,the self-diffusion coefficient, triplet OOO distribution, and thetemperature dependence of the density. This represents a significantadvancement in the field of polarizable machine learning potentialand computational modeling
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