A-optimal designs for an additive quadratic mixture model

Quadratic models are widely used in the analysis of experiments involving mixtures. This paper gives A-optimal designs for an additive quadratic mixture model for q ≥ 3 mixture components. It is proved that in these A-optimal designs, vertices of the simplex S q-1 are support points, and other support points shift gradually from barycentres of depth 1 to barycentres of depth 3 as q increases. A-optimal designs with minimal support are also discussed.published_or_final_versio

Domain freezing in potassium dihydrogen phosphate, triglycine sulfate, and CuAlZnNi

The temperature dependence of the dielectric constant and dissipation in potassium dihydrogen phosphate (KDP), its deuterated compound (DKDP), triglycine sulfate (TGS), and TGS doped with α-alanine (LATGS) has been studied at various frequencies. It is found that the relaxation time of domain freezing in KDP and DKDP in the kHz range can be described by the Vogel-Fulcher relation. Evidence of domain freezing in TGS is presented through an analysis of relaxation time related to domain walls and a comparison between TGS and LATGS. Studies of internal friction and compliance show preliminary evidence of domain freezing in CuAlZnNi alloy. A domain-freezing model is proposed based upon the collective pinning of randomly distributed pinning centers to domain walls. Some key experiments related to domain freezing, such as (1) the Vogel-Fulcher relation for relaxation time; (2) the size effect of domain freezing; (3) two kinds of relaxation in low- and high-frequency ranges, respectively; and (4) the dependence of TF on defect density and applied field, etc., are explained.published_or_final_versio

Optimal designs for an additive quadratic mixture model involving the amount of mixture

This paper is concerned with D- and A-optimal designs for a quadratic additive model for experiments with mixtures, in which the response depends not only on the relative proportions but also on the actual amounts of the mixture components. It is found that the origin and vertices of the simplex are support points of these optimal designs, and when the number of mixture components increases, other support points shift gradually from barycentres of depth 1 to barycentres of higher depths. It is shown that the D-optimal designs have high efficiency in terms of A-optimality, and vice versa.published_or_final_versio

Temperature dependent distinct coupling and dispersions of heavy- and light-hole excitonic polaritons in ZnO

Distinct coupling behavior of heavy- and light-hole excitonic polaritons in ZnO was unveiled by investigating the optical reflectance spectra of a high quality ZnO single crystal as a function of temperature both experimentally and theoretically. A resonance like coupling region was found at a temperature of around 50 K at which several relevant physical quantities such as the transverse exciton transition energy, polarizability, and damping parameters of the two kinds of excitonic polaritons were revealed to overturn. Calculated dispersions correctly reflect the nature of coupled photon and exciton and reproduce the spectral structures of the interacting polaritons. © 2012 American Institute of Physics.published_or_final_versio

Evolution of Wurtzite Structured GaAs Shells Around InAs Nanowire Cores

GaAs was radially deposited on InAs nanowires by metal–organic chemical vapor deposition and resultant nanowire heterostructures were characterized by detailed electron microscopy investigations. The GaAs shells have been grown in wurtzite structure, epitaxially on the wurtzite structured InAs nanowire cores. The fundamental reason of structural evolution in terms of material nucleation and interfacial structure is given

Immuno-targeting the multifunctional CD38 using nanobody

published_or_final_versio

Speed Partitioning for Indexing Moving Objects

Indexing moving objects has been extensively studied in the past decades. Moving objects, such as vehicles and mobile device users, usually exhibit some patterns on their velocities, which can be utilized for velocity-based partitioning to improve performance of the indexes. Existing velocity-based partitioning techniques rely on some kinds of heuristics rather than analytically calculate the optimal solution. In this paper, we propose a novel speed partitioning technique based on a formal analysis over speed values of the moving objects. We first show that speed partitioning will significantly reduce the search space expansion which has direct impacts on query performance of the indexes. Next we formulate the optimal speed partitioning problem based on search space expansion analysis and then compute the optimal solution using dynamic programming. We then build the partitioned indexing system where queries are duplicated and processed in each index partition. Extensive experiments demonstrate that our method dramatically improves the performance of indexes for moving objects and outperforms other state-of-the-art velocity-based partitioning approaches

Recent changes of water discharge and sediment load in the Yellow River basin, China

The Yellow River basin contributes approximately 6% of the sediment load from all river systems globally, and the annual runoff directly supports 12% of the Chinese population. As a result, describing and understanding recent variations of water discharge and sediment load under global change scenarios are of considerable importance. The present study considers the annual hydrologic series of the water discharge and sediment load of the Yellow River basin obtained from 15 gauging stations (10 mainstream, 5 tributaries). The Mann-Kendall test method was adopted to detect both gradual and abrupt change of hydrological series since the 1950s. With the exception of the area draining to the Upper Tangnaihai station, results indicate that both water discharge and sediment load have decreased significantly (p<0.05). The declining trend is greater with distance downstream, and drainage area has a significant positive effect on the rate of decline. It is suggested that the abrupt change of the water discharge from the late 1980s to the early 1990s arose from human extraction, and that the abrupt change in sediment load was linked to disturbance from reservoir construction.Geography, PhysicalGeosciences, MultidisciplinarySCI(E)43ARTICLE4541-5613

Digit-only sauropod pes trackways from China - evidence of swimming or a preservational phenomenon?

For more than 70 years unusual sauropod trackways have played a pivotal role in debates about the swimming ability of sauropods. Most claims that sauropods could swim have been based on manus-only or manus-dominated trackways. However none of these incomplete trackways has been entirely convincing, and most have proved to be taphonomic artifacts, either undertracks or the result of differential depth of penetration of manus and pes tracks, but otherwise showed the typical pattern of normal walking trackways. Here we report an assemblage of unusual sauropod tracks from the Lower Cretaceous Hekou Group of Gansu Province, northern China, characterized by the preservation of only the pes claw traces, that we interpret as having been left by walking, not buoyant or swimming, individuals. They are interpreted as the result of animals moving on a soft mud-silt substrate, projecting their claws deeply to register their traces on an underlying sand layer where they gained more grip during progression. Other sauropod walking trackways on the same surface with both pes and manus traces preserved, were probably left earlier on relatively firm substrates that predated the deposition of soft mud and silt . Presently, there is no convincing evidence of swimming sauropods from their trackways, which is not to say that sauropods did not swim at all

Significance of temperature and soil water content on soil respiration in three desert ecosystems in Northwest China

It is crucial to understand how abiotic factors influence soil respiration and to determine, in a quantitative manner, the site variation of abiotic regulators in desert ecosystems. In this study, soil respiration was measured using an automated CO2 efflux system (LI-COR 8100) in 2005 and 2006. Additionally, the effects of soil temperature, moisture and a short-term precipitation manipulation on the rate of soil respiration were examined in Haloxylon ammodendron, Anabasis aphylla and Halostachys caspica in three distinct desert ecosystems. The difference in soil respiration among sites was significant. Air temperature explained 35-65% of the seasonal changes in soil respiration when an exponential equation was used. The effect of temperature on soil respiration and temperature sensitivity was stronger at sites with higher soil moisture. Soil respiration was significantly positively correlated with soil moisture. Amounts of variation in soil respiration explained by temperature and gravimetric water content were 41-44% in H. ammodendron, 62-65% in A. aphylla and 67-84% in H. caspica sites. Artificial rainfall treatments of 5 mm, 2.5 mm and 0 mm (control) were conducted. Soil respiration increased in a small pulse following rainfall. Temperature dominantly influenced soil respiration and soil water content enhanced the response of respiration to temperature. (C) 2010 Elsevier Ltd. All rights reserved