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A novel copper (II) probe based on pyridinium salt was designed and synthesized, and the structure was confirmed by NMR and high-resolution mass spectrometry (HRMS). The probe exhibits strong orange fluorescent emission, and shows high selectivity for copper (II) over other cations. It may qualitatively identify copper ions from many metal cations without the use of any instruments. The fluorescent intensity at 572 nm decreases linearly with copper (II) concentration in the range of 0–10 µM. A remarkable detection limit (0.045 µM) can be achieved. [ABSTRACT FROM AUTHOR]

Digital pathology workflows in toxicologic pathology rely on whole slide images (WSIs) from histopathology slides. Inconsistent color reproduction by WSI scanners of different models and from different manufacturers can result in different color representations and inter-scanner color variation in the WSIs. Although pathologists can accommodate a range of color variation during their evaluation of WSIs, color variability can degrade the performance of computational applications in digital pathology. In particular, color variability can compromise the generalization of artificial intelligence applications to large volumes of data from diverse sources. To address these challenges, we developed a process that includes two modules: (1) assessing the color reproducibility of our scanners and the color variation among them and (2) applying color correction to WSIs to minimize the color deviation and variation. Our process ensures consistent color reproduction across WSI scanners and enhances color homogeneity in WSIs, and its flexibility enables easy integration as a post-processing step following scanning by WSI scanners of different models and from different manufacturers. [ABSTRACT FROM AUTHOR]

Flowering phenology and clonal growth are known to affect resource and pollen availability, and therefore select for adaptive or constrained sex allocation strategies to some degree. However, the consequences of temporal sex allocation patterns for reproductive fitness across the flower, inflorescence, and genet levels have rarely been examined. Moreover, experimental tests of the underlying regulatory mechanisms are scarce. We examined the association of flowering phenology and inflorescence position with temporal sex allocation and reproductive success in the protandrous perennial clonal herb, Aconitum kusnezoffii, over four consecutive growing seasons by examining more than 39 000 flowers. We also conducted controlled experiments to test the effects of resource and pollen limitation on the female reproductive success of lateral inflorescences. We found that some male functions were positively correlated with flowering phenology, whereas female reproductive success was negatively correlated with flowering phenology and inflorescence position. Lateral inflorescences invested more in male function than terminal inflorescences and therefore yielded fewer and smaller seeds. Resource limitation may serve as the key mechanism underlying this differentiated pattern. Decreased female reproductive success was consistently observed at the flower and inflorescence levels as flowering occurred later in the growth season. Late‐blooming lateral inflorescences specialized in the male function, and their female reproductive success was constrained by early‐blooming terminal inflorescences. This might be the first attempt to systematically demonstrate sex allocation strategy differentiation in a protandrous plant species at the inflorescence level. In addition, our study provides empirical evidence of dichogamy selecting for specialized sex allocation strategies among inflorescences. [ABSTRACT FROM AUTHOR]

In sparse linear regression, the SLOPE estimator generalizes LASSO by penalizing different coordinates of the estimate according to their magnitudes. In this paper, we present a precise performance characterization of SLOPE under the i.i.d. Gaussian design. We focus on the asymptotic regime where the number of unknown parameters grows in proportion to the number of observations. Our asymptotic characterization enables us to derive the fundamental limits of SLOPE in both estimation and variable selection settings. We also provide a computationally feasible way to optimally design the regularizing sequences to reach the aforementioned fundamental limits. In both settings, we show that the optimal design problem can be formulated as certain infinite-dimensional convex optimization problems that have efficient and accurate finite-dimensional approximations. Numerical simulations verify all our asymptotic predictions. They demonstrate the superiority of our optimal regularizing sequences over other designs used in the existing literature. [ABSTRACT FROM AUTHOR]

A Ni-WS2 sintered electrode was used to prepare a coating on a CrNi3MoVA steel substrate by employing electrospark deposition technique. The nanomechanical and tribological properties of the coating were tested by using nanoindenter and tribometer, and the morphologies, composition and phase structure were obtained by utilizing scanning electron microscopy (SEM), energy dispersive X-ray spectrum (EDS) and X-ray diffraction(XRD). The results showed that the coating is even-distributed with nanostalline α-W strengthening phase dopants, and it has a strong metallurgical bonding with the substrate. The coating is composed of WS2, γ-Ni, α-W and Ni3S2 phases, and it exhibits outstanding tribological properties for its friction coefficient reduced about 79% and wear rate reduced about 96% in contrast to the CrNi3MoVA steel. [ABSTRACT FROM AUTHOR]

We study a spectral initialization method that serves a key role in recent work on estimating signals in non-convex settings. Previous analysis of this method focuses on the phase retrieval problem and provides only performance bounds. In this paper, we consider arbitrary generalized linear sensing models and present a precise asymptotic characterization of the performance of the method in the high-dimensional limit. Our analysis also reveals a phase transition phenomenon that depends on the ratio between the number of samples and the signal dimension. When the ratio is below a minimum threshold, the estimates given by the spectral method are no better than random guesses drawn from a uniform distribution on the hypersphere, thus carrying no information; above a maximum threshold, the estimates become increasingly aligned with the target signal. The computational complexity of the method, as measured by the spectral gap, is also markedly different in the two phases. Worked examples and numerical results are provided to illustrate and verify the analytical predictions. In particular, simulations show that our asymptotic formulas provide accurate predictions for the actual performance of the spectral method even at moderate signal dimensions. [ABSTRACT FROM AUTHOR]

Ecological restoration has become increasingly important in conservation. Yet, synthesized statistics are scarce with respect to essential characteristics of restoration activities. We surveyed restoration stakeholders in the U.S. states of Arizona and California to evaluate key attributes in restoration activities including ecosystems of focus, goals, size, cost, duration, and the prevalence of recommended restoration practices. We also examined how some of the attributes varied with size of restoration, ecosystem type, and state identity. While enhancing biodiversity and increasing plant cover were common goals in the two states, restoration in California also focused more on wildlife habitat re‐establishment and weed control. Restoration in Arizona was implemented more in arid/semiarid systems, larger in size, shorter in duration, used more passive restoration, spent more on equipment, and was less likely to source plants from native plant nurseries. Labor was the most expensive restoration component regardless of state identity and ecosystem type. Per unit area cost of restoration decreased with increasing size of restoration. Yet, the decline in this cost was more strongly explained by moving from mesic to arid/semiarid ecosystems. Duration of restoration projects increased with size of restoration and in more mesic ecosystems. Overall, restoration in mesic ecosystems, compared to arid/semiarid systems, was smaller in size, higher in cost, and longer in duration. These results confirmed that ecological and socio‐political conditions impact restoration goals and practice, with implications of how research can further support practitioners to achieve restoration success under practical constraints revealed by these results. [ABSTRACT FROM AUTHOR]

Soil-borne fungi influence coexistence of plant species in mesic environments, but much less is known about their effects on demographic processes relevant to coexistence in arid and semi-arid systems. We isolated 43 fungal strains that naturally colonize seeds of an invasive winter annual (Brassica tournefortii) in the Sonoran Desert, and evaluated the impact of 18 of them on seed germination and mortality of B. tournefortii and a co-occurring native annual (Plantago ovata) under simulated summer and winter temperatures. Fungi isolated from B. tournefortii seeds impacted germination and mortality of seeds of both plant species in vitro. Seed responses reflected host-specific effects by fungi, the degree of which differed significantly between the strains, and depended on the temperature. In the winter temperature, ten fungal strains increased or reduced seed germination, but substantial seed mortality due to fungi was not observed. Two strains increased germination of P. ovata more strongly than B. tournefortii. In the summer temperature, fungi induced both substantial seed germination and mortality, with ten strains demonstrating host-specificity. Under natural conditions, host-specific effects of fungi on seed germination may further differentiate plant species niche in germination response, with a potential of promoting coexistence. Both host-specific and non-host-specific effects of fungi on seed loss may induce polarizing effects on plant coexistence depending on the ecological context. The coexistence theory provides a clear framework to interpret these polarizing effects. Moreover, fungi pathogenic to both plant species could induce host-specific germination, which challenges the theoretical assumption of density-independent germination response. These implications from an in vitro study underscore the need to weave theoretical modeling, reductive empirical experiments, and natural observations to illuminate effects of soil-borne fungi on coexistence of annual plant species in variable desert environments. [ABSTRACT FROM AUTHOR]

Substantial progress has been made recently on developing provably accurate and efficient algorithms for low-rank matrix factorization via nonconvex optimization. While conventional wisdom often takes a dim view of nonconvex optimization algorithms due to their susceptibility to spurious local minima, simple iterative methods such as gradient descent have been remarkably successful in practice. The theoretical footings, however, had been largely lacking until recently. In this tutorial-style overview, we highlight the important role of statistical models in enabling efficient nonconvex optimization with performance guarantees. We review two contrasting approaches: (1) two-stage algorithms, which consist of a tailored initialization step followed by successive refinement; and (2) global landscape analysis and initialization-free algorithms. Several canonical matrix factorization problems are discussed, including but not limited to matrix sensing, phase retrieval, matrix completion, blind deconvolution, and robust principal component analysis. Special care is taken to illustrate the key technical insights underlying their analyses. This article serves as a testament that the integrated consideration of optimization and statistics leads to fruitful research findings. [ABSTRACT FROM AUTHOR]

Phylogenetically informed trait comparisons across entire communities show promise in advancing community ecology. We use this approach to better understand the composition of a community of winter annual plants with multiple decades of monitoring and detailed morphological, phenological and physiological measurements. Previous research on this system revealed a physiological trade‐off among dominant species that accurately predicts population and community dynamics. Here we expanded our investigation to 51 species, representing 96% of individual plants recorded over 30 years, and analysed trait relationships in the context of species abundance and phylogenetic relationships. We found that the functional‐trait trade‐off scales to the entire community, albeit with diminished strength. It is strongest for dominant species and weakens as progressively rarer species are included. The trade‐off has been consistently expressed over three decades of environmental change despite some turnover in the identity of dominant species. [ABSTRACT FROM AUTHOR]

Highlights • Sintered Nd-Fe-B strip casting flakes (SC) and waste sintered magnets (SM) show the approximate HD process, which accelerates with increasing pressure. • The surface activation process accelerates with increasing pressure, and almost disappears when the initial hydrogen pressure reaches to 6 MPa. • The hydrogen content of SM is lower than SC, and increases with increasing pressure. • For the SM, blasting power of HD process decreases with the increase of the initial hydrogen pressure. Abstract Hydrogen treatment technology is developed to recycle the waste Nd-Fe-B sintered magnets in the way of short route, low cost, and high efficiency. In present study, effect of hydrogen pressure on hydrogen decrepitation (HD) process of sintered Nd-Fe-B strip casting flakes (SC) and waste sintered magnets (SM) was systematically studied. Both SC and SM show the approximate HD process, which accelerates with increasing pressure. The surface activation process accelerates with increasing pressure, and almost disappears when the initial hydrogen pressure reaches to 6 MPa. The hydrogen content of SM is lower than SC, and increases with increasing pressure. For the SM, blasting power of HD process decreases with the increase of the initial hydrogen pressure. It provides beneficial reference for recycling waste Nd-Fe-B sintered magnets. [ABSTRACT FROM AUTHOR]

Abstract Digital image correlation (DIC) method has been widely used for measurement in high temperature environment, where speckle pattern that can withstand high temperature and maintain good stability is required. In this work we develop a simple method to fabricate speckle pattern for high temperature application. The curing temperature of the speckle is controlled under 350 °C to avoid potential damage to the substrate material. The speckle can resist temperature up to 1050 °C for minimum 0.5 h. Three point bending experiment was carried out at 700 °C to test the speckle. Results show that this high temperature speckle exhibits excellent adhesion to the substrate. This non-invasive speckle shows great potential for improving the measurement reliability at high temperature in engineering application. [ABSTRACT FROM AUTHOR]

In this paper, we studied the magnetic hardening mechanism of SmCo6.6Nb0.4 nanoflakes prepared by surfactant-assisted high energy ball milling. The hysteresis loop with the initial magnetization curve and the corresponding differential susceptibility curve of thermally demagnetized SmCo6.6Nb0.4 nanoflakes were studied. It is concluded that the magnetization reversal process of the specimen is determined by domain wall motion, i.e., the magnetic hardening mechanism of the magnetic powders is dominated by domain wall pinning. Moreover, the dependence of coercive field of the nanoflakes on the maximum applied field derived from minor hysteresis loops also confirms the pinning effect in the magnetization reversal. [ABSTRACT FROM AUTHOR]

Eryngium sparganophyllum is a perennial endemic to ciénegas in warm North American deserts. Only four populations remain, yet little scientific knowledge exists to guide its conservation. Based on a spatially balanced sampling design, we quantified plant density, individual size, and reproductive potential of two populations in the U.S. We also assessed conditions influencing germination in the lab. The population in a warmer climate had a larger population size, higher short-term population growth rate, hosted larger individuals, and showed a negative correlation between plant size and plant density. In both populations, plant density was positively correlated with shallow soil moisture and probability of flowering was positively correlated with plant size. Seeds only germinated in the spring, and responded to interactions between temperature, light exposure and population location. We hypothesize that 1) recruitment of E. sparganophyllum may be episodic, relying on a rare niche opportunity of reliable shallow soil moisture and low competition; and 2) adult survival of the species may be limited by interspecific density dependence and climatic extremes. The conservation of this species depends on ensuring high adult survival and promoting recruitment, which can be accomplished through actively protecting extant populations and exploring restoration and introduction possibilities. • One population in a warmer climate was larger and denser than the other. • Both population declined after a severe drought followed by a historic wet summer. • Seed germination occurs in the spring and is sensitive to temperature and light. • Recruitment may be episodic due to rare niche requirement. • Active ciénega management is necessary to encourage recruitment and adult survival. [ABSTRACT FROM AUTHOR]

Effect of homogenization of the chemical composition and crystal structure on the magnetocaloric effects have been studied for bulk Mn1.1Fe1.9P1.8Ge0.2 alloy prepared by mechanical alloying and subsequent spark plasma sintering method. After optimal homogenization treatment, the ferromagnetic impurity, Ge6Fe3Mn4 phase was completely eliminated from the alloy; furthermore, the crystal lattice constant of the MnFePGe main phase, which possesses a hexagonal Fe2P-type structure, varies obviously compared with that of the sintered sample. As a result, the Curie temperature, TC, of the alloy increases from 253 to 267.5 K and the maximum magnetic entropy change, /ΔSm/, also increases from 36.36 to 44.35 J /kg K under 3 T magnetic field. Furthermore, the thermal hysteresis of M-T curves around TC upon heating and cooling, a signature of a first-order magnetic phase transition, reduces from 15 K for as-sintered sample to 9 K for annealed sample. [ABSTRACT FROM AUTHOR]

The crystal structure and magnetic transition were studied for the bulk Mn1.1Fe0.9P0.8Ge0.2 compound prepared by a simple blending and subsequent spark plasma sintering route. X-ray diffraction analysis and refinement show that the compound crystallizes in the hexagonal Fe2P-type structure, in which the Mn atoms occupy all the 3g sites and some 3f sites, the Fe atoms occupy the rest of the 3f sites, and P and the Ge atoms randomly occupy the 2c and 1b sites. Magnetic measurement indicates that the Curie temperature TC is at 253 K and the thermal hysteresis of M-T curves at TC upon heating and cooling, a signature of a first-order magnetic phase transition, is about 15 K. The maximum magnetic entropy change of the compound reaches as high as 49.2 J/kg K in a field change from 0 to 5 T at 253 K, while the adiabatic temperature change of the compound reaches only 1.2 K in a field change from 0 to 1.5 T at the same temperature. [ABSTRACT FROM AUTHOR]

Nd–Fe–B nanoparticles have been obtained by using surfactant-assisted ball milling and subsequent size-selection technique. Structural analyses show that nanoparticles with two particle sizes around 10 and 100 nm were obtained. The partially amorphous Nd–Fe–B nanoparticles give their room-temperature coercivities around 0.1 and 1.5 kOe for the small and large nanoparticles, respectively. As the temperature decreases to 200 K, the coercive force of the large nanoparticles increases by 50% due to the enhancement of the magnetocrystalline anisotropy of the Nd2Fe14B phase in the particles. [ABSTRACT FROM AUTHOR]

Polarization curve and electrochemical impedance spectroscopy tests have been applied to investigate the corrosion kinetics for both spark plasma sintered (SPS) and conventional sintered Nd–Fe–B magnets in different electrolytes. Effect of microstructure modification on the chemical stability of the magnets was discussed. Both magnets exhibit evident passive behavior in alkaline electrolyte but are susceptible to corrosion in weak acid and saline electrolytes. SPS magnets are more corrosion resistant than conventional sintered magnets due to a remarkable microstructure modification formed in the SPS process. Further investigation shows that the unique microstructure in SPS magnets effectively restrains the aggressive intergranular corrosion which takes place along Nd-rich phases in conventional magnets. [ABSTRACT FROM AUTHOR]

Chemical coating, hot compaction, and hot deformation techniques have been applied to prepare bulk isotropic and anisotropic Nd2Fe14B/α-Fe nanocomposite magnets. The effect of α-Fe content on the structure and magnetic properties of the magnets were studied. For the isotropic magnets, the remanence (Br) increases as the α-Fe content increases, while the coercive force (Hci) drops simultaneously. For the anisotropic magnets, the Br rises first, peaking at 2 vol % of α-Fe content, then falls as the α-Fe content increases, and Hci drops significantly for all the α-Fe containing anisotropic magnets. Crystal structure analysis shows that only the magnets with no more than 2 vol % α-Fe exhibit strong c-axis crystal texture of Nd2Fe14B phase after deformation. Microstructure observation also shows that there are many Nd2Fe14B equiaxial grains even after hot deformation in the magnets with α-Fe more than 2 vol %. [ABSTRACT FROM AUTHOR]

Oxidation kinetics of Nd–Fe–B permanent magnets prepared by both spark plasma sintering (SPS) and conventional sintering techniques has been studied at elevated temperature in dry air environment. Compared with the conventional sintered magnet, the SPS magnet possesses much lower oxidation rate, which leads to less reduction of magnetic properties of the SPS magnet than that of the conventional sintered magnet. Microstructure observation shows that the SPS magnet possesses unique microstructure due to the special sintering mechanism of SPS technique. In detail, the grain size of the Nd2Fe14B main phase is fine and uniform, only a few Nd-rich phases form along the grain boundaries of Nd2Fe14B phase, while most of them agglomerate into triple junctions as small particles. Such microstructure modification restrains effectively the intergranular corrosion along Nd-rich phase in the SPS magnet. As a result, the SPS magnet possesses excellent corrosion resistance at elevated temperature. [ABSTRACT FROM AUTHOR]

A series of layer structural composite magnetic refrigerant materials with composition of (Gd5Si2Ge2)x(Gd)y(Gd5Si1.85Ge2.15)z was synthesized via spark plasma sintering technique. The adiabatic temperature change (ΔTad) of the composites and of the three individual components was measured directly from 245 to 315 K with a magnetic field change of 1.5 T using a homemade magnetocaloric effect measuring apparatus. For all composites with different x:y:z ratios, their resultant ΔTad uniformly peaks at 246, 276, and 296 K, respectively, corresponding to the magnetic transition temperature of the three components. In addition, proper x:y:z ratio can improve both the value and the constancy of ΔTad of the composite. Compared with the three components, the value of ΔTad of the composites exhibits a more constant tendency, which is more suitable for practical application in room temperature refrigeration, when compared to those of the three components. [ABSTRACT FROM AUTHOR]

The correlation between preparation conditions and microstructure as well as magnetic properties were studied for Sm(Co 0.665 Fe 0.25 Cu 0.06 Zr 0.025 ) 7 magnets. Increase of sintering temperature from 1468 to 1493 K promotes the amalgamation of small grains into big ones, resulting in an enlargement of average grain size from 10 to 25 μm and diffusion of Cu from inner grains to Cu-lean grain boundaries. As a result, the demagnetization curve squareness of the magnets improves substantially, leading to a remarkable enhancement of the maximum energy product from 21.3 to 27.1 MGOe. The coercivity of the magnets drops from 25.3 to 16.0 kOe at the same time, which was verified by the increase of the average domain width from 1.1 μm in small grains to 2.5 μm in big grains. It is therefore concluded that tuning of the preparation conditions causes a more homogeneous distribution of Cu, which is crucial for the improvement of magnetic properties. [ABSTRACT FROM AUTHOR]

Finding the sparse representation of a signal in an overcomplete dictionary has attracted a lot of attention over the past years. This paper studies ProSparse, a new polynomial complexity algorithm that solves the sparse representation problem when the underlying dictionary is the union of a Vandermonde matrix and a banded matrix. Unlike our previous work, which establishes deterministic (worst-case) sparsity bounds for ProSparse to succeed, this paper presents a probabilistic average-case analysis of the algorithm. Based on a generating-function approach, closed-form expressions for the exact success probabilities of ProSparse are given. The success probabilities are also analyzed in the high-dimensional regime. This asymptotic analysis characterizes a sharp phase transition phenomenon regarding the performance of the algorithm. [ABSTRACT FROM AUTHOR]

Microstructure modification induced giant coercivity enhancement from 950 to 1688 kA/m has been achieved in Sm(Co 0.665 Fe 0.25 Cu 0.06 Zr 0.025 ) 7 permanent magnets via Cu powders doping. Microstructure observation shows that in original magnet there are Cu-lean regions along the grain boundary area, where regular cellular structure does not form. After Cu powders doping, most Cu-lean regions disappear. Comparison of magnetic domain reversal between the original magnet and doped magnet indicates that reversed domain propagation was substantially restrained due to the elimination of the Cu-lean region. Moreover, the pinning field increases by 83.3% after Cu doping, having good agreement with coercivity enhancement. [ABSTRACT FROM AUTHOR]

Spark plasma sintering technique has been applied to synthesize composite Gdx(Gd5Si2Ge2)1-x (x=0.3, 0.5, and 0.7) with layer structure using high-purity gadolinium (Gd) metal and Gd5Si2Ge2 alloys. The magnetocaloric effect of the composites was studied by directly measuring adiabatic temperature change (ΔTad) with a magnetic-field change of 1.5 T using a homemade magnetocaloric effect measuring apparatus. With increasing x from 0.3 to 0.7, ΔTad peak temperature shifted from 286 to 293 K and the peak values of ΔTad slowly increased from 1.6 to 2.0 K at a magnetic-field change of 1.5 T. Meanwhile, the ΔTad peak of the composite broadened as Gd content was increased. For x=0.7, the composite showed a ΔTad ranging from 1.1 to 2.0 K at a magnetic-field change of 1.5 T in a temperature range of 260–300 K, which adapted to work as a room-temperature refrigerant. [ABSTRACT FROM AUTHOR]

The vertical sections of Fe-12%Cr-B-xAl-C system with different aluminum contents have been calculated by use of Thermo-Calc software and the influence of aluminum content on the phase regions and the parameters of eutectic point have been analyzed. Fe-12.0%Cr-1.0%B-2.0%Al-0.3%C and Fe-12.0%Cr-1.0%B-4.0%Al-0.3%C alloy were chosen to be studied by experiment. The phase transition temperatures were measured by differential scanning calorimetry and the microstructure and the phase type was detected by scanning electrone microscope-energy dispersive X-ray spectroscopy and X-ray diffraction. The results indicate that calculated phase diagrams agree well with the experimental results and further prove the thermodynamics database of Thermo-Calc software is reliable and it can be used to help design the alloy composition and heat treatment process. [ABSTRACT FROM AUTHOR]

In this paper, the recoil loops of SmCo6.6Nb0.4 nanoflakes prepared by the surfactant-assisted high energy ball milling (SA-HEBM) were systematically studied. The recoil loop openness was observed in both the aligned and non-aligned samples. Reversible and irreversible portions of the demagnetization process derived from the recoil loop were also investigated. For both the aligned and non-aligned samples, reversible portion (Δmrev) is too small to determine the coercivity. Irreversible portion (Δmirrev) shows similar tendency, i.e. increasing slowly at low reverse field and then growing up rapidly after a critical field (nucleation field Hno). The demagnetization process can be described as following: the reversible demagnetization is dominant when the applied reverse field is lower than 8 kOe, under which the irreversible nucleation also occurs. The reverse domain walls are pinned by the grain boundaries until the reverse field is larger than 8 kOe. With increasing field, the pinning effects are weakened and the rapid reversible demagnetization starts. Finally, the demagnetization process is accomplished. The values of AM in the Henkel plots are totally opposite for the aligned and non-aligned SmCo6.6Nb0.4 nanoflakes. [ABSTRACT FROM AUTHOR]

Sm1-xPrxCo5 (x=0-0.6) nanoflakes with CaCu5 structure were successfully prepared by surfactant-assisted high-energy ball milling (SAHEBM). The crystal structure and magnetic properties of Sm1-xPrxCo5 (x=0-0.6) nanoflakes were studied by X-ray diffraction and vibrating sample magnetometer. Effects of Pr addition on the structure, magnetic properties and coercivity mechanism of Sm1-xPrxCo5 nanoflakes were systematically investigated. XRD results show that all the nanoflakes have a hexagonal CaCu5-type (Sm, Pr)1Co5 main phase and the (Sm, Pr)2Co7 impurity phase, and all of the samples exhibit a strong (00l) texture after magnetic alignment. As the Pr content increases, remanence firstly increases, then slightly reduced, while anisotropy field (HA) and Hci of decrease monotonically. Maximum energy product [(BH)max] of the flakes increases first, peaks at 24.4 MGOe with Pr content of x = 0.4, then drops again. Magnetization behavior analysis indicate that the coercivity mechanism is mainly controlled by inhomogeneous domain wall pinning, and the pinning strength weakens with the increased Pr content, suggesting the great influence of HA on the coercivity of flakes. [ABSTRACT FROM AUTHOR]

Commercial NdFeB powders mixed with DyH x nanoparticles are hot pressed and hot deformed into anisotropic magnets by Spark Plasma Sintering (SPS). The hot deformed magnet exhibits strong c -axis crystallographic texture. The coercivity of the magnet doped with 1.0 wt% DyH x is increased by 66.7%, compared with the magnet without DyH x , while the remanence decreases only by 3%. TEM observation shows that there exists a continuous (Nd,Dy) 2 Fe 14 B layer between Nd-rich phase and NdFeB main phase. [ABSTRACT FROM AUTHOR]

In present study, the hysteresis loops and the magnetic reversal process of both the parallel and the perpendicular oriented Nd 2 Fe 14 B/Fe 65 Co 35 /Nd 2 Fe 14 B trilayers with different soft phase thicknesses were studied by the micro-magnetism finite element method. Analysis of magnetization vectors' evolution in demagnetization process indicates that the parallel and the perpendicular oriented trilayers exhibit different magnetic reversal behaviors. All the demagnetization curves of the perpendicular oriented trilayers exhibits “single phase” behavior, while noticeable kinks presents in the demagnetization curves of the parallel oriented trilayers with the soft phase thickness equal to or larger than 12 nm. Moreover, as the thickness of the soft phase increases, the remanence (Br) of the parallel and the perpendicular oriented trilayers increases first, peaks respectively at 1.90 and 1.93 T, respectively, and then decreases again. On the other hand, the coercivity ( μ 0 H c ) of the parallel and the perpendicular oriented trilayers drops monotonically with the increase of soft layers thickness. As a result, the optimal maximum energy product [(BH) max ] of the parallel and the perpendicular oriented trilayers are 630 kJ/m 3 and 592 kJ/m 3 , respectively. Deviation degree of orientation was simulated for the perpendicular oriented trilayers with Ls =10 nm. [ABSTRACT FROM AUTHOR]

The waste Nd–Fe–B sintered magnets up to 500 kg per batch were recycled to manufacture anisotropic sintered magnets by combination of hydrogen decrepitation (HD) and alloying technique. Magnetic properties and thermal stability of both the waste magnets and recycled magnets were investigated. The recycled magnet exhibits magnetic properties with remanence (B r ) of 12.38 kGs, coercivity (H ci ) of 24.89 kOe, and maximum energy product [(BH) max ] of 36.51 MGOe, respectively, which restores 99.20% of B r , 105.65% of H ci , and 98.65% of (BH) max of the waste magnets, respectively. The volume fraction of Nd-rich phase in the recycled magnets is about 10.1 vol.%, which is bigger than that of the waste magnets due to the additive of Nd 3 PrFe 14 B alloy containing more rare earth. The remanence temperature coefficient (α) and coercivity temperature coefficient (β) of the recycled magnets are −0.1155%/K and −0.5099%/K in the range of 288–423 K, respectively, which are comparative to those of the waste magnets. [ABSTRACT FROM AUTHOR]

Demagnetization curves of anisotropic nanocomposite MnBi/Co and MnBi/Fe 65 Co 35 permanent magnets were investigated by micro-magnetic finite element method. Effects of volume ratio, deviation degree of orientation and intrinsic magnetic properties of the soft magnetic phase on the magnetic properties of the magnets were investigated. From the viewpoint of practical applications, to meet the requirement of hardness parameters, ĸ = K /( μ 0 M S 2 ) 1/2 >1, the calculation maximum (BH)max of MnBi/Co and MnBi/Fe 65 Co 35 magnets are about 199 kJ/m 3 (V(Co)=22 vol%) and 196 kJ/m 3 (V(FeCo)=14 vol%), respectively, indicating their good potential in application. Compared with single phase MnBi magnet, the (BH) max of nanocomposite MnBi/Co and MnBi/Fe 65 Co 35 magnets increases by 66% and 63%, respectively. The remanence and coercivity of MnBi/Co nanocomposite magnets reduce as appearing a deviation degree of orientation, result of greatly decrease of the magnetic energy product. [ABSTRACT FROM AUTHOR]

Crystal structure and magnetic properties have been studied for bulk MnFePSi compounds prepared by the spark plasma sintering method. The effect of Si content on the crystal structure and the magnetic properties of the compounds were investigated. The MnFePSi compounds crystallize in a hexagonal Fe2P-type structure without obvious secondary phase. Magnetic measurements indicate that the compounds undergo a ferromagnetic to paramagnetic first-order transition near their Curie temperature ( TC) . With the increase in Si content, the TC rises from 343 to 381 K, while \Delta T\mathrm{ hys} decreases simultaneously from 27 to 15 K. For MnFeP0.5Si0.5 compound, the magnetic entropy change ( - \Delta SM) for a magnetic field change from 0 to 3 T is 12 J/kg \cdot \textK , demonstrating its good potential for practical application. [ABSTRACT FROM AUTHOR]

Our recent targeted sequencing study identified a missense single-nucleotide polymorphism rs72474224 (c. 324C>T) in GJB2. To investigate the correlation between rs72474224 (c. 324C>T) and subphenotypes of psoriasis, genotype data for rs72474224 (c. 324C>T, p. Val37Ile) was analyzed in 9946 cases and 9906 controls. The additive model provided the best fit for rs72474224 ( P = 7.34 × 10−9). The genotypic and allelic frequency distributions were associated with plaque psoriasis in case-only ( Pgenotype = 2.67 × 10−3, Pallele = 6.22 × 10−4) and subphenotype-control ( Pgenotype = 1.58 × 10−11, Pallele = 8.16 × 10−12) analyses. No other significant difference was found in case-only analyses. Rs72474224 in GJB2 is preferentially associated with plaque psoriasis in Chinese population and might contribute to the complexity of psoriasis clinical features. [ABSTRACT FROM AUTHOR]

Structure and magnetic properties were studied for Sm–Fe–N nanoparticles prepared by surfactant-aid high energy ball milling. Magnetic hardening mechanism of the particles was investigated by evaluating their initial magnetization curves. The particles with average size of 750 nm, 36.5 nm, and 9.4 nm exhibit high coercivity of 12.4, 18.7, and 7.5 kOe, respectively. As particle size decreases, the magnetization process switches from pinning to nucleation behavior, indicating that particle size plays a key role in determining the magnetic hardening mechanism of the nanoparticles. [ABSTRACT FROM AUTHOR]

Mutations in the LRRK2 gene represent the most common genetic cause of late onset Parkinson's disease. The physiological and pathological roles of LRRK2 are yet to be fully determined but evidence points towards LRRK2 mutations causing a gain in kinase function, impacting on neuronal maintenance, vesicular dynamics and neurotransmitter release. To explore the role of physiological levels of mutant LRRK2, we created knock-in (KI) mice harboring the most common LRRK2 mutation G2019S in their own genome. We have performed comprehensive dopaminergic, behavioral and neuropathological analyses in this model up to 24 months of age. We find elevated kinase activity in the brain of both heterozygous and homozygous mice. Although normal at 6 months, by 12 months of age, basal and pharmacologically induced extracellular release of dopamine is impaired in both heterozygous and homozygous mice, corroborating previous findings in transgenic models over-expressing mutant LRRK2. Via in vivo microdialysis measurement of basal and drug-evoked extracellular release of dopamine and its metabolites, our findings indicate that exocytotic release from the vesicular pool is impaired. Furthermore, profound mitochondrial abnormalities are evident in the striatum of older homozygous G2019S KI mice, which are consistent with mitochondrial fission arrest. We anticipate that this G2019S mouse line will be a useful pre-clinical model for further evaluation of early mechanistic events in LRRK2 pathogenesis and for second-hit approaches to model disease progression. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate absorption characteristics of zinc glycine chelate (Zn-Gly) by evaluating tissues zinc status and the expression of zinc transporters in rats. A total of 24 male rats were randomly allocated to three treatments and administered either saline or 35 mg Zn/kg body weight from zinc sulphate (ZnSO4) or Zn-Gly by feeding tube separately. Four rats per group were slaughtered and tissues were collected at 2 and 6 h after gavage respectively. Our data showed that Zn-Gly did more effectively in increasing (p < 0.05) serum zinc levels, and the activities of serum and liver alkaline phosphatase (ALP) and liver Cu/Zn superoxide dismutase (Cu/Zn SOD) at 2 and 6 h. By 2 h after the zinc load, the mRNA and protein abundance of intestinal metallothionein1 (MT1) and zinc transporter SLC30A1 (ZnT1) were higher (p < 0.05), and zinc transporter SLC39A4 (Zip4) lower (p < 0.05) in ZnSO4 compared to other groups. Zinc transporter SLC39A5 (Zip5) mRNA expression was not zinc responsive, but Zip5 protein abundance was remarkably (p < 0.05) increased in ZnSO4 2 h later. Overall, our results indicated that in short-term periods, Zn-Gly was more effective in improving body zinc status than ZnSO4, and ZnSO4 did more efficiently on the regulation of zinc transporters in small intestine. [ABSTRACT FROM AUTHOR]

Multiple scale-dependent ecological processes influence species distributions. Uncovering these drivers of dynamic range boundaries can provide fundamental ecological insights and vital knowledge for species management. We develop a transferable methodology that uses widely available data and tools to determine critical scales in range expansion and to infer dominating scale-dependent forces that influence spread. We divide a focal geographic region into different sized square cells, representing different spatial scales. We then used herbarium records to determine the species' occupancy of cells at each spatial scale. We calculated the growth in cell occupancy across scales to infer the scale dependent expansion rate. This is the first time such a 'box-counting' method is used to study range expansion. We coupled this multi-scale analysis with species distribution models to determine the range and spatial scales where suitable climate allows the species to spread, and where other factors may be influencing the expansion. We demonstrate our methodology by assessing the spread of invasive Sahara mustard in North America. We detect critical scales where its spread is limited (100-500 km) or unconstrained (5-50 km) by climatic variables. Using climate-based models to assess the similarity of climate envelopes in its native and invaded range, we find that the climate in the invaded range generally predicts the native distribution, suggesting that either there has been little local adaptation to climate occurring since introduction or the biological interaction experienced in the invaded range has not driven the species to occupy climatic conditions much different from its native range. Our novel method can be broadly utilized in other studies to generate critical insights into the scale dependency of different ecological drivers that influence the spread and distribution limits, as well as to help parameterizing predictions of future spread, and thus inform management decisions. [ABSTRACT FROM AUTHOR]

We consider the classical problem of finding the sparse representation of a signal in a pair of bases. When both bases are orthogonal, it is known that the sparse representation is unique when the sparsity K of the signal satisfies K<1/\mu ( {\boldsymbol {D}}) , where \mu ( {\boldsymbol {D}}) is the mutual coherence of the dictionary. Furthermore, the sparse representation can be obtained in polynomial time by basis pursuit (BP), when K<0.91/\mu ( \boldsymbol D) . Therefore, there is a gap between the unicity condition and the one required to use the polynomial-complexity BP formulation. For the case of general dictionaries, it is also well known that finding the sparse representation under the only constraint of unicity is NP-hard. In this paper, we introduce, for the case of Fourier and canonical bases, a polynomial complexity algorithm that finds all the possible K -sparse representations of a signal under the weaker condition that K<\sqrt 2 /\mu ( \boldsymbol D) . Consequently, when K<1/\mu ( \boldsymbol D) , the proposed algorithm solves the unique sparse representation problem for this structured dictionary in polynomial time. We further show that the same method can be extended to many other pairs of bases, one of which must have local atoms. Examples include the union of Fourier and local Fourier bases, the union of discrete cosine transform and canonical bases, and the union of random Gaussian and canonical bases. [ABSTRACT FROM PUBLISHER]

The effects of quenching temperature on microstructure and hardness of cast Fe-8Cr-2B alloy containing 0.3 wt% C, 2.0 wt% B, 8.0 wt% Cr, 0.6 wt% Si, and 0.8 wt% Mn were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Rockwell hardness and Vickers microhardness testers. The experimental results indicate that the as-cast microstructure of cast Fe-8Cr-2B alloy consists of M2B (M = Fe, Cr), M7(C, B)3, α-Fe, and γ-Fe. The dendritic matrix composed of lath martensite mixed with a small amount of retained austenite, and the netlike boride M2B distribute in the grain boundary. After quenching between 950 °C and 1100 °C, the netlike eutectic boride are broken up and a new phase-M23(C, B)6 which is distributed in the shape of sphere or short rod-like are precipitated from the matrix. Both the macrohardness and microhardness of specimens increase with the increasing quenching temperature. At about 1050 °C, the hardness reaches the maximum value. However, when the temperature exceeds 1050 °C, the hardness will decrease slightly. With the increase of tempering temperature, the hardness of cast Fe-8Cr-2B alloy quenching from 1050 °C decreases gradually and its impact toughness increases slightly. Crusher hammer made of cast Fe-8Cr-2B alloy quenching from 1050 °C and tempering from 300 °C has good application effect, and its service life improves by 150-180% than that of high manganese steel hammer. [ABSTRACT FROM AUTHOR]

In this paper, thermodynamics properties of a laser detector applied in 105 mm shrapnel with high rotation speed have been explored. In outer trajectory, aerodynamic heating usually generates because of viscosity, and this is strengthened by high rotation speed of the shrapnel. Thermal strain may occur, which will influence the overall power of the detector and shrapnel. The temperature has been computed by computational fluid dynamics method, and ANSYS Workbench has been applied to obtain thermal strain. In order to disclose the effect of rotation, comparison among simulation results in different conditions are carried out. It is figured out that the temperature increase does not exceed the limit of optical material (polymethyl methacrylate), so the function of laser detector and the power of shrapnel will not be affected. This paper demonstrates the feasibility of material choice of laser detector optical systems. It has important theoretical meaning and practical application value for the design of conventional ammunition laser detector. [ABSTRACT FROM AUTHOR]

We examined the morphological and physiological responses of Osmanthus fragrans 'Yingui' (Yin) and O. fragrans 'Jingui' (Jin) to different NaCl concentrations. NaCl concentrations significantly affected plant height and leaf mass per area. Total biomass decreased by 22.8-41.8% under moderate and high NaCl which inhibited O. fragrans growth. The ratio of root to shoot biomass in Yin was 44.3% higher than that in Jin at high NaCl concentrations which suggested that Yin possesses conservative resource acquisition strategies to resist salt stress. Compared to Yin, Jin showed higher net photosynthesis, stomatal conductance, and intercellular CO2 concentration under high NaCl treatment. Jin exhibited also relatively higher proline, soluble sugar, K+ content, and K+/Na+ under the treatments implying that acquisitive resource acquisition may be the main strategy for salt resistance in Jin. Our results demonstrated that Yin and Jin could be cultivated in saline land in a short time and the two cultivars respond to salinity by different morphological and physiological mechanisms. [ABSTRACT FROM AUTHOR]

The spectral theory of graphs provides a bridge between classical signal processing and the nascent field of graph signal processing. In this paper, a spectral graph analogy to Heisenberg's celebrated uncertainty principle is developed. Just as the classical result provides a tradeoff between signal localization in time and frequency, this result provides a fundamental tradeoff between a signal's localization on a graph and in its spectral domain. Using the eigenvectors of the graph Laplacian as a surrogate Fourier basis, quantitative definitions of graph and spectral “spreads” are given, and a complete characterization of the feasibility region of these two quantities is developed. In particular, the lower boundary of the region, referred to as the uncertainty curve, is shown to be achieved by eigenvectors associated with the smallest eigenvalues of an affine family of matrices. The convexity of the uncertainty curve allows it to be found to within \varepsilon by a fast approximation algorithm requiring \cal O(\varepsilon^-1/2) typically sparse eigenvalue evaluations. Closed-form expressions for the uncertainty curves for some special classes of graphs are derived, and an accurate analytical approximation for the expected uncertainty curve of Erdős-Rényi random graphs is developed. These theoretical results are validated by numerical experiments, which also reveal an intriguing connection between diffusion processes on graphs and the uncertainty bounds. [ABSTRACT FROM AUTHOR]

Abstract: Crystal structure, and thermal and magnetic properties have been studied for bulk MnFePSiGe compounds with different silicon contents prepared by the spark plasma sintering method. The MnFePSiGe compounds crystallize in a hexagonal Fe2P-type structure without obvious secondary phase. The compounds undergo a ferromagnetic to paramagnetic first-order transition near their Curie temperature (T C). With increase of Si content, both T C and magnetic entropy change (−ΔS M) of the compounds rise remarkably, while the thermal hysteresis (T hys) remains almost invariant. For MnFeP0.63Si0.26Ge0.11 compound, the T C and −ΔS M for a magnetic field change from 0 to 2T are 318K and 27.9J/KgK, respectively, and its phase transition entropy change (ΔS) obtained from DSC is 32.3J/KgK. [Copyright &y& Elsevier]

Abstract: This paper reports a Markov model based approach to systematically evaluating the proliferation resistance (PR) of nuclear energy systems (NESs). The focus of the study is on the development of the Markov models for a class of complex PR scenarios, i.e., mixed covert/overt strategy switching proliferation, for NESs with two modes of material flow, batch and continuous. In particular, a set of diversion and/or breakout scenarios and covert/overt misuse scenarios are studied in detail for an Example Sodium Fast Reactor (ESFR) system. Both probabilistic and deterministic PR measures are calculated using a software tool that implements the proposed approach and can be used to quantitatively compare proliferation resistant characteristics of different scenarios for a given NES, according to the computed PR measures. [Copyright &y& Elsevier]

The relationship between environmental productivity and the number of species [species richness-productivity relationship ( SRPR)] has been thoroughly studied, but the mechanisms responsible for its form are still largely unknown, possibly because the majority of studies have focused on evaluating the sole effect of a single hypothesis., We tested whether variation in species richness along a productivity gradient is due to variation in (i) the number of individuals, (ii) the number of species in the species pool or (iii) habitat heterogeneity., We measured species richness ( S), individual abundance ( N) and productivity ( P) estimated as standing biomass in different herbaceous communities in the Czech Republic at two spatial scales. Species pool ( Spool) was obtained from a database concerning individual habitats, and habitat heterogeneity ( H) was measured using the community dissimilarity index., The SRPR was scale-dependent: at the smaller spatial scale of individual plots, there was a significant curvilinearly negative relationship between S and P, whereas at the larger site scale it turned into a non-significant relationship., Species richness was significantly affected by a combined effect of N and Spool at the plot scale and by a combined effect of Spool and H at the site scale. None of these variables was sufficient to explain the SRPR by itself., Synthesis. Our findings indicate that there is no universal form of the species-productivity relationship, and the SRPR is driven by multiple scale-dependent mechanisms. It is important to consider the joint effect of different factors in explaining species richness patterns rather than to focus on the sole effect of productivity. [ABSTRACT FROM AUTHOR]

Abstract: Surfactant assist ball milling, chemical coating, and hot compaction techniques have been applied to prepare bulk anisotropic SmCo5/α-Fe nanocomposite permanent magnets. The effects of α-Fe content on the structure and magnetic properties of the magnets were studied. As the α-Fe content increases, the remanence of the magnets increases first, peaking at 5wt.% of α-Fe content, then falls as the α-Fe content increases, while the coercive force of the magnets drops simultaneously. Crystal structure analysis shows that all the magnets exhibit noticeable c-axis crystal texture of SmCo5 phase. The SmCo5/α-Fe magnet with 5wt.% α-Fe possesses M 2.3T of 78.68emu/g, Mr of 70.03emu/g, and Hci of 8.02kOe. [Copyright &y& Elsevier]

We study a new image sensor that is reminiscent of a traditional photographic film. Each pixel in the sensor has a binary response, giving only a 1-bit quantized measurement of the local light intensity. To analyze its performance, we formulate the oversampled binary sensing scheme as a parameter estimation problem based on quantized Poisson statistics. We show that, with a single-photon quantization threshold and large oversampling factors, the Cramér–Rao lower bound (CRLB) of the estimation variance approaches that of an ideal unquantized sensor, i.e., as if there were no quantization in the sensor measurements. Furthermore, the CRLB is shown to be asymptotically achievable by the maximum-likelihood estimator (MLE). By showing that the log-likelihood function of our problem is concave, we guarantee the global optimality of iterative algorithms in finding the MLE. Numerical results on both synthetic data and images taken by a prototype sensor verify our theoretical analysis and demonstrate the effectiveness of our image reconstruction algorithm. They also suggest the potential application of the oversampled binary sensing scheme in high dynamic range photography. [ABSTRACT FROM AUTHOR]

Inner suspension platform of a spherical robot undergoes dynamic oscillation process when the robot is rolling ahead, which significantly reduces stability and precision of the motion. To suppress these vibrations, this study considers an adaptive sliding mode control method for a spherical robot based on application of magnetorheological (MR) fluid actuator. After analyzing the mechanical structure of the spherical robot, a dynamic model describing its rolling motion is derived. Considering the uncertainty of the disturbances introduced by modeling error and outside perturbation, an adaptive scheme is proposed to estimate the dynamic disturbances. Sliding mode technology is applied to construct system controller characterized by robustness and parameter insensibility. Simulations are performed in order to verify the effectiveness of the proposed control methods. [ABSTRACT FROM AUTHOR]