CONTEXT: The Amur tiger and leopard, once roaming over the Eurasian continent, are now endangered and confined to the Sikhote-Alin Mountains, Russia—a landscape that has been increasingly fragmented ...due to human activities. The ultimate fate of these big cats depends on whether they can resettle in their previous main historical range in NE China. Recent sightings of these animals along the China–Russia border have aroused new hope, but direct evidence is lacking. OBJECTIVES: The main objectives of our study were (1) to determine the abundance and spatiotemporal patterns of tigers, leopards, and primary prey; (2) to investigate factors influencing the resettlement of the two big cats; and (3) to propose a landscape-scale conservation plan to secure the long-term sustainability of the Amur tiger and leopard. METHODS: We monitored the two felids, their prey, and human activities, with 380 camera-trap stations, for a total of 175,127 trap days and over an area of 6000 km² in NE China. We used the constraint line method to characterize cattle grazing and human influences on tigers, leopards, and their prey species. RESULTS: Our results show that, unexpectedly, at least 26 tigers and 42 leopards are present within China, which are confined primarily to a narrow area along the border with Russia. We have further identified that cattle grazing and human disturbances are the key hurdles to the dispersal of the tigers and leopards farther into China where suitable habitat is potentially available. CONCLUSIONS: Amur tigers and leopards are returning to China, indeed, but their long-term resettlement is not likely without active and timely conservation efforts on landscape and regional scales. To overcome the hurdles to the resettlement of tigers and leopards in China, we propose a “Tiger and Leopard Resettlement Program” that will engage the government, local communities, and researchers, so that the long-term sustainability of the Amur tigers and leopards can be ensured.
Abstract We report the phase-resolved spectral results of the first Galactic pulsating ultraluminous X-ray source (PULX) Swift J0243.6+6124, modeling its 2017–2018 outburst peak using data collected ...by the Hard X-ray Modulation Telescope (Insight-HXMT). The broad energy coverage of Insight-HXMT allows us to obtain a more accurate spectral continuum to reduce the coupling of broad iron line profiles with other components. We use three different continuum spectrum models but obtain similar iron line results. For the first time, we detect the pulse characteristics of the broad iron line in a PULX. The variation in the width and intensity of this iron line with σ ∼ 1.2–1.5 keV has a phase offset of about 0.25 from the pulse phase. We suggest that the uneven irradiation of the thick inner disk by the accretion column produces the modulated variation of the broad iron line. In addition, the nonpulsed narrow line is suggested to come from the outer disk region.
The Martian plasma environment contains a complex magnetic topology, with contributions from the interplanetary magnetic field (IMF) and crustal magnetic fields. The topology can control how plasma ...is exchanged between the solar wind and the Martian ionosphere. Here we use 7 years of suprathermal electron pitch angle distributions recorded by the Mars Global Surveyor (MGS) spacecraft to determine the topology at 2 am and 400 km on the Martian nightside as a function of geographic location and external drivers. Observations show that topology statistically varies with IMF direction, solar wind pressure, solar extreme ultraviolet (EUV) flux, and season. Changes in topology with IMF direction and season are consistent with changes in the likelihood of magnetic reconnection between individual crustal fields and the draped IMF. Changes in topology at a given location with solar wind pressure and solar EUV flux are consistent with reconfiguration of topological structures in the plasma environment.
Key Points
Magnetic topology on the nightside of Mars responds in systematic ways to external drivers
Changes in interplanetary magnetic field direction or in season are consistent with changes in topology via magnetic reconnection
Changes in solar wind ram pressure or in solar EUV flux are consistent with changes in the measured topology via reconfiguration
A modified single edge notch tension (SENT) specimen exposed to saline environment was used to investigate the stress corrosion cracking and corrosion fatigue cracking behavior of A7N01P‐T4 aluminum ...alloy. The crack propagation rate was determined, the microstructure, crack growth path, and the fracture surfaces of specimens were examined by optical microscopy (OM) and scanning electron microscopy (SEM). The results showed that the stress corrosion cracking rate of A7N01P‐T4 alloy in 3.5% NaCl was three orders lower than that of corrosion fatigue crack propagation rate. Mg and Zn segregation at the grain boundaries increased the stress corrosion crack susceptibility. The grain orientation had a significant effect on the crack propagation performance, and the high angle grain boundaries were susceptible to cracking. Hydrogen embrittlement was the primary cause of stress corrosion crack and corrosion fatigue crack propagation.
SCC and CFCP behavior of A7N01P‐T4 aluminum were investigated, the results show that Cl− promotes crack initiation and growth. Hydrogen embrittlement was the primary cause of crack propagation.
Charge exchange between highly charged ions and neutral atoms and molecules has been considered as one of the important mechanisms controlling soft X-ray emissions in many astrophysical objects and ...environments. However, for modeling charge exchange soft X-ray emission, the data of n- and l-resolved state-selective capture cross sections are often obtained by empirical and semiclassical theory calculations. With a newly built cold target recoil-ion momentum spectroscopy (COLTRIMS) apparatus, we perform a series of measurements of the charge exchange of Ne(8,9)+ ions with He and H2 for collision energy ranging from 1 to 24.75 keV/u. n-resolved state-selective capture cross sections are reported. By comparing the measured state-selective capture cross sections to those calculated by the multichannel Landau–Zener method (MCLZ), it is found that MCLZ calculations are in good agreement with the measurement for the dominant n capture for He target. Furthermore, by using nl-resolved cross sections calculated by MCLZ and applying l distributions commonly used in the astrophysical literature to experimentally derived n-resolved cross sections, we calculate the soft X-ray emissions in the charge exchange between 4 keV/u Ne8+ and He by considering the radiative cascade from the excited Ne7+ ions. Reasonable agreement is found in comparison to the measurement for even and separable models, and MCLZ calculations give results in a better agreement.
Near‐field enhanced bifunctional plasmonic‐magnetic (PM) nanostructures consisting of silica nanotubes with embedded solid nanomagnets and uniformly dual‐surface‐coated plasmonic Ag nanoparticles ...(NPs) are rationally synthesized. The solid embedded sections of nanotubes provide single‐molecule sensitivity with an enhancement factor up to 7.2 × 109 for surface‐enhanced Raman scattering (SERS). More than 2× SERS enhancement is observed from the hollow section compared to the solid section of the same nanotube. The substantial SERS enhancement on the hollow section is attributed to the dual‐sided coating of Ag NPs as well as the near‐field optical coupling of Ag NPs across the nanotube walls. Experimentation and modeling are carried out to understand the dependence of SERS enhancement on the NP sizes, junctions, and the near field effects. By tuning the aspect ratio of the embedded nanomagnets, the magnetic anisotropy of nanotubes can be readily controlled to be parallel or vertical to the long directions for nano‐manipulation. Leveraging the bifunctionality, a nanotube is magnetically maneuvered to a single living mammalian cell amidst many and its membrane composition is analyzed via SERS spectroscopy.
Unique near‐field enhanced plasmonic‐magnetic bifunctional nanotubes are fabricated and their plasmonic properties are investigated by both experimentation and theoretical modeling. By leveraging the bifunctionality, a nanotube can be precisely transported to a single living Chinese hamster ovary (CHO) cell amidst many and its membrane chemistry (lipid and protein) is revealed with surface‐enhanced Raman scattering (SERS) spectroscopy.
Abstract
Polymer composites are gradually replacing traditional metal materials in the fields of aviation, aerospace, automotive and medicine due to their corrosion resistance, light weight and high ...strength. Moulding technology and organization morphology of polymer composite are key elements affecting the quality of products and their application, so a vacuum hot pressing process for graphene
x
/poly(ether ketone ketone) (PEKK) (x = 0%, 2%, 3%, 4%, 5%, 6%) composite powders is explored with particularly designed moulding parameters to achieve high conductive properties and good mechanical properties in graphene/PEKK composite sheet with thickness of 1.25 mm and diameter of 80 mm. The vacuum environment ensures that the graphene is not oxidized by air during hot pressing molding, which is essential for achieving conductive property in the graphene/PEKK composite; The hot pressing temperature of each graphene/PEKK composite powder is higher than glass transition temperature but lower than melting temperature, which ensures the graphene/PEKK composite powders is fully compacted and then graphene is fully lapped in the composite sheet. In addition, the graphene/PEKK composite sheet shows conductive property when the graphene content increases to 3wt%, and then the conductivity of the composites increases and then decreases with a peak value at 5wt% with increasing graphene content. By comparing the mechanical properties and microstructure morphology of the graphene/PEKK composite sheets, it was obtained that graphene content has an obvious effect on the mechanical properties of the composites, e.g., the mechanical properties will be increased as the graphene content increasing when graphene content is more than 3%. The graphene distribution law of the composite material with different graphene contents is analysed using a scanning electron microscope (SEM).
This paper presents the nonlinear interval optimization (NIO) model to solve optimal power system dispatch (OPSD) with uncertain wind power integrated. In this model, not only the average of the ...dispatching objective, but its deviation are also taken into account. Therefore, the NIO model based on OPSD is formulated as a multi-objective optimization problem. An optimization algorithm, group search optimizer with multiple producers (GSOMP) is applied to obtain Pareto solutions, which show the tradeoff relationship between the average and deviation of the dispatching objective. Then, a decision-making method, the evidential reasoning (ER) approach, is applied to determine the final dispatch solution. Simulation results based on the modified IEEE 30-bus system prove the applicability and effectiveness of the NIO model to deal with the OPSD, considering the integration of the uncertain wind power.
To assess the safety of road vehicles running over a long span bridge in high wind, the knowledge of aerodynamic forces and moments on the vehicles is required. This could be obtained through wind ...tunnel investigations and expressed in terms of aerodynamic coefficients. However, very few investigations have been carried out to find aerodynamic coefficients of road vehicles on a bridge deck, compared with the aerodynamic coefficients of road vehicles on the ground. This paper therefore presents the results of wind tunnel tests carried out to determine aerodynamic coefficients of four types of road vehicles over a typical bridge deck. The aerodynamic coefficients of the same road vehicles on the ground are also presented to explore the effects of the bridge deck on aerodynamic coefficients. Different wind directions are taken into consideration to observe variations of aerodynamic coefficients with wind direction. Furthermore, the effects of vehicle position in different road lanes of the bridge deck are investigated. The test results show that the existence of bridge deck reduces side forces for all four types of vehicles remarkably but increases rolling moments to some extent. Such effects also vary with types of vehicles and lanes of the bridge deck where vehicles run.
Purpose
T4-binding globulin (TBG) is the main thyroid hormone (TH) transporter present in human serum. Inherited thyroxine-binding globulin (TBG) deficiency is caused by mutations in the
TBG
(
...SERPINA7
) gene, which is located on the X chromosome. This study was performed to report and evaluate coding region mutations in
TBG
gene for partial thyroxine-binding globulin deficiency.
Methods
A pedigree spanning four generations is described in this study. The proband is a female with partial TBG deficiency. All members of this pedigree underwent thyroid function tests, while Sanger sequencing was used to identify the
TBG
gene mutations. Bioinformatics databases were used to evaluate the deleterious effects of the mutation(s). Two hundred and seven unrelated individuals were used to evaluate the thyroid function of individuals with different
TBG
mutations. A one-way ANOVA was used to analyze the impact of the
TBG
mutations on thyroid function.
Results
TBG
gene sequencing results revealed that the proband had a novel mutation in codon 27 leading to alanine to valine substitution (p.A27V). This mutation was associated with lower serum T4 levels (
p
< 0.0001) when compared to the groups that did not carry the mutation. The previously reported p.L283F mutation was also found in the proband. The hemizygous p.L283F individuals presenting with lower T4 serum and TBG levels (
p
< 0.001) when compared to wildtype males and females. Both mutations were deleterious upon SIFT and PolyPhen-2 evaluation.
Conclusion
Associated with partial thyroxine-binding globulin deficiency, this study reports a novel p.A27V mutation in the
TBG
gene.
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