134,126 research outputs found
Difference based Ridge and Liu type Estimators in Semiparametric Regression Models
No full textWe consider a difference based ridge regression estimator and a Liu type estimator of the regression parameters in the partial linear semiparametric regression model, y = Xβ + f + ε. Both estimators are analysed and compared in the sense of mean-squared error. We consider the case of independent errors with equal variance and give conditions under which the proposed estimators are superior to the unbiased difference based estimation technique. We extend the results to account for heteroscedasticity and autocovariance in the error terms. Finally, we illustrate the performance of these estimators with an application to the determinants of electricity consumption in Germany.Difference based estimator; Differencing estimator, Differencing matrix, Liu estimator, Liu type estimator, Multicollinearity, Ridge regression estimator, Semiparametric model
ECHOES OF DECLASSIFIED INTELLIGENCE SATELLITE PHOTOGRAPHS: THEIR ROLE AND APPLICATION IN THE RESEARCH AND PRESERVATION OF CHINA’S BUILT VERNACULAR HERITAGE
No full textVernacular architecture is constructed spontaneously and used by ordinary people, and they have been subject to constant modifications by changes in ownership, functions, and constructions according to people’s living demands. In the last two decades, many cases which were constructed in the traditional way and survived China’s overwhelming urbanization process have been listed in the preservation list with the increasing interest in cultural heritage. Regarding this type of heritage that is a result of multiple modifications, many restorations aim to recover the changed architecture to traditional formal integrity. Due to the rarity of detailed written or image references, some restorations become a kind of “creation” and fall into the cliché of stylistic restoration, which is posing an artificial risk to their historical values. Facing this difficulty, the authors turn to an important historical record - the DISP (declassified intelligence satellite photographs): since 1995, the US has declassified three batches of satellite photographs that were taken from the 1960s to the 1980s, before China’s great change in Reform and Opening Up, almost covering all of China. These photographs are an important historical photographic record of the territory as well as the vernacular architecture scattered on it. This paper uses two cases to illustrate the important role of these photographs in China’s built vernacular heritage: both as a reference to restoration and as a valuable source for historical research. The authors also discuss the prospect and limitations of this source
Intercalation of polypyrrole into graphite oxide
No full textIn this paper we report on the insertion of polypyrrole into layered graphite oxide. This was achieved by using the exfoliating and re-stacking properties of the host. The resulting intercalated product was characterized by powder X-ray diffraction, FT-IR spectroscopy, thermogravimetric analysis and scanning electron microscopy. (c) 2006 Elsevier B.V. All rights reserved.PT: J; CR: *ACS, 1996, ACS SYM SER, P622 BISSESSUR R, 2001, CHEM COMMUN 0907, P1598 BISSESSUR R, 2003, J MATER CHEM, V13, P44 BISSESSUR R, 2004, J MATER SCI, V39, P119 CASSAGNEAU T, 1998, ADV MATER, V10, P877 CASSAGNEAU T, 2000, LANGMUIR, V16, P7318 DING RF, 2003, POLYM DEGRAD STABIL, V81, P473 HUMMERS WS, 1958, J AM CHEM SOC, V80, P1339 KANATZIDIS MG, 1993, CHEM MATER, V5, P595 KOVTYUKHOVA NI, 1999, CHEM MATER, V11, P771 LIU ZH, 2002, LANGMUIR, V18, P4926 MATSUO Y, 1997, CARBON, V35, P113 MATSUO Y, 1998, CHEM MATER, V10, P2266 MATSUO Y, 2002, J MATER CHEM, V12, P1592 NAKAJIMA T, 1988, CARBON, V26, P357 WANG L, 1995, CHEM MATER, V7, P1753 WU CG, 1989, POLYM MATER SCI ENG, V61, P969 XIAO M, 2002, POLYMER, V43, P2245 XIAO P, 2000, CARBON, V38, P623; NR: 19; TC: 0; J9: SYNTHET METAL; PG: 5; GA: 093UXSource type: Electronic(1
Asymptotic stability analysis of nonlinear stochastic semi-Markov jump systems
No full textIn this article, three different types of stochastic asymptotic stability for nonlinear stochastic semi-Markov jump systems (SSMJS) are investigated. Novel sufficient conditions for pth (p>0) \left(p>0\right) -moment asymptotic stability, almost sure asymptotic stability and stochastic asymptotic stability in the large are obtained. It is remarkable that the obtained results in the latter case cover the results in existing literature. Finally, two examples are presented to confirm the validity of the obtained theoretical results
Thermonuclear 19F(p, α0)16O reaction rate
No full textThe thermonuclear 19F(p, α0)16O reaction rate in the temperature region 0.007-10 GK has been derived by re-evaluating the available experimental data, together with the low-energy theoretical R-matrix extrapolations. Our new rate deviates by up to about 30% compared to the previous results, although all rates are consistent within the uncertainties. At very low temperature (e.g. 0.01 GK) our reaction rate is about 20% lower than the most recently published rate, because of a difference in the low energy extrapolated S-factor and a more accurate estimate of the reduced mass used in the calculation of the reaction rate. At temperatures above ∼1 GK, our rate is lower, for instance, by about 20% around 1.75 GK, because we have re-evaluated the previous data (Isoya et al., Nucl. Phys. 7, 116 (1958)) in a meticulous way. The present interpretation is supported by the direct experimental data. The uncertainties of the present evaluated rate are estimated to be about 20% in the temperature region below 0.2 GK, and are mainly caused by the lack of low-energy experimental data and the large uncertainties in the existing data. Asymptotic giant branch (AGB) stars evolve at temperatures below 0.2 GK, where the 19F(p, α0)16O reaction may play a very important role. However, the current accuracy of the reaction rate is insufficient to help to describe, in a careful way, the fluorine over-abundances observed in AGB stars. Precise cross section (or S factor) data in the low energy region are therefore needed for astrophysical nucleosynthesis studies
Necessary and sufficient conditions for moment stability of positive Markov jump linear systems
No full textThis paper focuses on the problems of stability for positive Markov jump linear systems (PMJLSs) and its application to nonlinear Markov jump stochastic systems (MJSSs). First, we provide sufficient and necessary conditions for p -moment exponential stability of PMJLS. Then, based on the proposed results on p-moment exponential stability of PMJLS, we obtain explicit stability criteria for nonlinear MJSSs. Finally, two numerical examples are presented to confirm the validity of the obtained theoretical results.(c) 2022 Elsevier Ltd. All rights reserved
At most single-bend embeddings of cubic graphs
No full textThis paper provides the complete proof of the fact that any planar cubic graph is at most single-bend embeddable except for the tetrahedron. An O(n) amortized time algorithm for drawing an at most single-bend embedding of a cubic graph is also presented, where n is the number of vertices of the graph. Furthermore, it is proved that the minimum of the total number of bends in an at most single-bend embedding of a cubic graph of order n is less than or equal to 0.5 n+1. This result is the best possible. © 1994 Editorial Committee of Applied Mathematics-A Journal of Chinese Universities
Ammonia and Methane Emission Factors from Cattle Operations Expressed as Losses of Dietary Nutrients or Energy
No full textCitation: Liu, Z.; Liu, Y.; Murphy, J.P.; Maghirang, R. Ammonia and Methane Emission Factors from Cattle Operations Expressed as Losses of Dietary Nutrients or Energy. Agriculture 2017, 7, 16.The objective of this study was to conduct a systematic review of published literature on ammonia (NH3) and enteric methane (CH4) emissions from beef and dairy cattle operations to obtain statistically representative emission factors based on dietary intakes of nutrients or energy, and to identify major causes of emission variations. NH3emissions from lagoon or other manure storage facilities were not included in this review. The NH3 and CH4 emission rates, expressed as a percentage losses of dietary nutrients or energy, demonstrated much less variation compared with emission rates expressed in g/animal/day. Air temperature and dietary crude protein (CP) content were identified as two major factors that can affect NH3 emission rates in addition to farm type. Feed digestibility and energy intake were identified as two major factors that can affect CH4 emission rates expressed as a percentage losses of dietary energy. Generally, increasing productivity and feed efficiency represented the greatest opportunity for mitigating NH3 or CH4 emissions per unit of livestock product. Expressing CH4loss on a digestible energy basis rather than a gross energy intake basis can better represent the large variation among diets and the effects of varying dietary emission mitigation strategies
Illustrations of <i>Beilschmiedia turbinata</i> Bing Liu & Y. Yang showing morphological details.
No full text<p>A, seedling; B, Flowering branch; C, flower; D, flower (front part removed); E, the first whorl perianth lobe; F, the second whorl perianth lobe; G. the first whorl stamen (adaxial view); H, the second whorl stamen (adaxial view); I, the third whorl stamen (abaxial view); J, the fourth whorl staminode (abaxial view); K, pistil showing the pubescent ovary; L, terminal bud; M, venation pattern (abaxial view); N, fruiting branch in the second year; O, a young fruit in the first year (Drawn by Y. B. Sun, A from <i>Bing Liu 1184</i>, B–M from <i>Bing Liu 1442</i>, N–O from <i>Bing Liu 1185, PE</i>).</p
Lithium extraction from shale gas flowback and produced water using H1.33Mn1.67O4 adsorbent
No full textThe rapid growth of demand for lithium, especially in lithium batteries calls for an increase in the supply of lithium resources. We synthesized H1.33Mn1.67O4 adsorbent by solid-phase reaction method to recover lithium for the first time from shale gas flowback and produced water (SGFPW) in the Sichuan Basin, China. Na2CO3 precipitation pre-treatment was employed to improve the adsorption capacity and selectivity of lithium. The adsorption capacity of lithium in the pre-treated water (P-SGFPW) was 16.24 mg/g higher than that in SGFPW (13.27 mg/g), and the partition coefficient of Li+ increased from 731.58 to 1073.58 mL/g after precipitation. After four cycles of adsorption and desorption, the adsorption capacity of lithium was stable and showed only a slight decrease equal to 3.53% and 5.35% in P-SGFPW and SGFPW, respectively. H1.33Mn1.67O4 is a promising adsorbent for lithium extraction from SGFPW, and precipitation before adsorption can improve its performance significantly
- …
