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Testing for unit roots in bounded time series
No full textMany key economic and financial series are bounded either by construction or through policy controls. Conventional unit root tests are potentially unreliable in the presence of bounds, since they tend to over-reject the null hypothesis of a unit root, even asymptotically. So far, very little work has been undertaken to develop unit root tests which can be applied to bounded time series. In this paper we address this gap in the literature by proposing unit root tests which are valid in the presence of bounds. We present new augmented Dickey–Fuller type tests as well as new versions of the modified ‘M’ tests developed by Ng and Perron [Ng, S., Perron, P., 2001. LAG length selection and the construction of unit root tests with good size and power. Econometrica 69, 1519–1554] and demonstrate how these tests, combined with a simulation-based method to retrieve the relevant critical values, make it possible to control size asymptotically. A Monte Carlo study suggests that the proposed tests perform well in finite samples. Moreover, the tests outperform the Phillips–Perron type tests originally proposed in Cavaliere [Cavaliere, G., 2005. Limited time series with a unit root. Econometric Theory 21, 907–945]. An illustrative application to U.S. interest rate data is provide
A simplified way to manufacture high-Q microfiber coil resonators by controlling the input/output coupling
No full textThe dependence of the Q-factor of the microfiber coil resonator on different input/output couplings is investigated and compared. A method of slowly varying input/output coupling is presented to considerably simplify the fabrication of high-Q resonators
The existence of -tree-connected -factors using -factors and -tree-connected -factors
No full textLet be a graph and let , , and be three positive
integer-valued functions on with . Tokuda, Xu, and Wang (2003)
showed that if contains a -factor and a spanning -tree, then
also contains a connected -factor. In this note, we develop their
result to a tree-connected version by proving that if contains a
-factor and an -tree-connected -factor, then also
contains an -tree-connected -factor, provided that . In
addition, we show that allows to be nonnegative.Comment: This paper is an improved version of a removed part of the paper
arXiv:1702.0620
PLATE 77. A, B, F, G. Chelae, holotypes. C. Pronotum, lateral view. D, E. Heads, holotypes. A in <strong>Dryinidae of the Oriental region (Hymenoptera: Chrysidoidea)</strong>
No full textPLATE 77. A, B, F, G. Chelae, holotypes. C. Pronotum, lateral view. D, E. Heads, holotypes. A. Dryinus choui (from Olmi 1993b). B. D. exilis (from Olmi 1984). C. D. expolitus, female from Ryukyu (from Mita, 2009b). D, G. D. fulvus (from Olmi 1984). E. D. hainanensis (from Olmi 1987a). F. D. expolitus (from Xu et al. 2007). Scale bar 0.27 mm for A, 0.29 mm for B, 0.35 mm for F and G.Published as part of Xu, Zaifu, Olmi, Massimo & He, Junhua, 2013, Dryinidae of the Oriental region (Hymenoptera: Chrysidoidea), pp. 1-460 in Zootaxa 3614 (1) on page 269, DOI: 10.11646/zootaxa.3614.1.1, http://zenodo.org/record/527837
Supported ultrafine ruthenium oxides with specific capacitance up to 1099 F g(-1) for a supercapacitor
No full textReducing the particle size is a straightforward way to increase the specific surface area of ruthenium oxide, which usually translates to the high specific capacitance for a supercapacitor. Herein, we report a facile strategy to fabricate ultrafine ruthenium oxides supported on various carbon-based substrates (carbon powders, carbon nanotubes, or reduced graphene oxides) as excellent electrode materials for a supercapacitor. The novelty of this work lies in its synthetic approach, which involves an aqueous synthesis of ruthenium nanoclusters under the control of pH value, and an air oxidation-based conversion process. In particular, owing to their ultrafine particle size, the as-prepared carbon-, carbon nanotube-, or reduced graphene oxide-supported ruthenium oxides exhibit specific capacitance as high as 879.1 F g(-1), 966.8 F g(-1) and 1099.6 F g(-1), respectively, for a supercapacitor at a current density of 0.5 A g(-1). The specific capacitance maintains 98.4% (for carbon supports), 98.0% (for carbon nanotube supports) and 98.4% (for reduced graphene oxide supports) at current density of 1 A g(-1) with good cycling stability. The remarkable simplicity and environmental friendliness of this synthesis may provide a liable quantity production route to produce ruthenium oxides as highly efficient electrode materials for a supercapacitor. (C) 2016 Elsevier Ltd. All rights reserved
PLATE 45. A–C, F, G. Male genitalia. D, E. Chelae. A in Dryinidae of the Oriental region (Hymenoptera: Chrysidoidea)
No full textPLATE 45. A–C, F, G. Male genitalia. D, E. Chelae. A. Anteon songyangense, holotype (from Xu et al. 1998). B. A. songyangense from China. C. A. striolaforceps from China. D. A. spenceri (from Olmi 1991). E. A. subdignum, holotype (from Olmi 1992a). F. A. sulawesianum, holotype (from Olmi 1991). G. A. sulawesianum from China. Scale bar 0.22 mm for A and B, 0.18 mm for C and D, 0.15 mm for E, 0.13 mm for F and G.Published as part of <i>Xu, Zaifu, Olmi, Massimo & He, Junhua, 2013, Dryinidae of the Oriental region (Hymenoptera: Chrysidoidea), pp. 1-460 in Zootaxa 3614 (1)</i> on page 171, DOI: 10.11646/zootaxa.3614.1.1, <a href="http://zenodo.org/record/5278372">http://zenodo.org/record/5278372</a>
Cryptomya (Venatomya) sinensis Xu 1987
No full textCryptomya (Venatomya) sinensis (Xu, 1987) Figure 5 A–F Tugonia sinensis Xu, 1987: 438, 441, fig. 1 b—Bernard et al., 1993: 107; Xu, 1997: 230; Lutaenko & Xu, 2008: 52, text-fig. 6 D; Xu & Zhang, 2008: 257, fig. 814; Xu, 2008: 589. Cryptomya (Venatomya) sinensis (Xu, 1987) — Huber, 2010: 766. Material examined. MBM 300741 (no. 84 M- 185) (Holotype) (1 articutate shell), Huian, Fujian Province, China, on July 17 th, 1984. Distribution and habitat. Recent. East China Sea, Yellow Sea, China. Type locality. Huian, Fujian Province, China. Habitat unknown. Diagnosis. Length to 20 mm; shell laterally slightly compressed, thin and fragile; umbo prominent, situated slightly posterior, prosogyrate; sculpture of commarginal growth lines on anterior and anterorcentral shell, and radial ribs posterocentral to posterior, becoming more pronounced towards the posterior; posterior area lacking radial ribs; chondrophore in left valve shallow; pallial sinus shallow and broad, extending slightly beyond the posterior adductor scar; pallial line thin or obscure. Remarks. The shell of this species is slightly compressed and its posterior end is not attenuated as is typical of Tugonia. Our present placement with Cryptomya (Venatomya) coincides with Huber (2010: 766); however, we do not agree with his synonymization with C. (V.) elliptica. Based on our examinations of type specimens of C. (V.) sinensis and material of C. (V.) elliptica, the shell of C. (V.) elliptica is much more compressed than that of C. (V.) sinensis. Comparing shells of similar size, C. (V.) sinensis (MBM 300741, Length = 19.0 mm) is much more fragile, the sculpture stronger, and the umbo much larger and more tumid than in C. (V.) elliptica (MBM 136090, Length = 18.8 mm) (Fig. 5 G).Published as part of Zhang, Jun-Long, Xu, Feng-Shan & Liu, Rui-Yu, 2012, The Myidae (Mollusca, Bivalvia) from Chinese waters with description of a new species, pp. 39-60 in Zootaxa 3383 on page 49, DOI: 10.5281/zenodo.28173
Braiding structures on formal Poisson groups and classical solutions of the QYBE
No full textIf g is a quasitriangular Lie bialgebra, the formal Poisson group F[[g^*]] can be given a braiding structure. This was achieved by Weinstein and Xu using purely geometrical means, and independently by the authors by means of quantum groups. In this paper we compare these two approaches. First, we show that the braidings they produce share several similar properties (in particular, the construction is functorial); secondly, in the simplest case (G = SL_2) they do coincide. The question then rises of whether they are always the same this is positively answered in a separate paper
Figure 2 from: Xu Z, Tian J, Rapanarivo SHJV, Letsara R, Rakotonasolo RA, Onjalalaina GE, Hu G-W, Wang Q-F (2020) Hydrostachys flabellifera (Hydrostachyaceae), a new species from Madagascar. PhytoKeys 167: 45-56. https://doi.org/10.3897/phytokeys.167.58538
No full textFigure 2 Hydrostachys flabellifera G.W. Hu, Zhun Xu & Q.F. Wang A habit B emergences on rachis, cross-section C, D emergences E dorsal view of male bract F ventral view of male bract G top view of stamen
Adiabatic submicrometric tapers for optical tweezers
No full textAdiabatic tips have been manufactured from optical fibres and used as efficient optical tweezers. Trapping powers in the order of 10 mW have been used for 1 mm particles in water
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