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Underwater object detection is a prerequisite for underwater robots to achieve autonomous operation and ocean exploration. However, poor imaging quality, harsh underwater environments and concealed underwater targets greatly aggravate the difficulty of underwater object detection. In order to reduce underwater background interference and improve underwater object perception, we propose a multi-dimensional, multi-functional and multi-level attention module (mDFLAM). The multi-dimensional strategy first enhances the robustness of attention application by collecting valuable information in different target dimensions. The multi-functional strategy further improves the flexibility of attention calibration by capturing the importance of channel semantic information and the dependence of spatial location information. The multi-level strategy finally enriches the diversity of attention perception by extracting the intrinsic information under different receptive fields. In pre-processing and post-processing stages, cross-splitting and cross-linking stimulate the synergistic calibration advantage of multi-dimensional and multi-functional attention by redistributing channel dimensions and restoring feature states. In the attention calibration stage, adaptive fusion stimulates the synergistic calibration advantage of multi-level attention by assigning learnable parameters. In order to meet the high-precision and real-time requirements for underwater object detection, we integrate the plug-and-play mDFLAM into YOLO detectors. The full-port embedding further strengthens the semantic information expression by improving the feature fusion quality between scales. In underwater detection tasks, ablation and comparison experiments demonstrate the rationality and effectiveness of our attention design. In other detection tasks, our work shows good robustness and generalization. [ABSTRACT FROM AUTHOR]

The principal aim of present study was to assess the therapeutic efficacy of bone morphogenetic protein-7 (BMP-7) induced differentiation of bone marrow mesenchymal stem cells (BMSCs) in a rat acute spinal cord injury (SCI) model. BMSCs were isolated from rats, and then divided into a control and a BMP-7 induction groups. The proliferation ability of BMSCs and glial cell markers were determined. Forty Sprague–Dawley (SD) rats were randomly divided into sham, SCI, BMSC, and BMP7 + BMSC groups (n = 10). Among these rats, the recovery of hind limb motor function, the pathological related markers, and motor evoked potentials (MEP) were identified. BMSCs differentiated into neuron-like cells after the introduction of exogenous BMP-7. Interestingly, the expression levels of MAP-2 and Nestin increased, whereas the expression level of GFAP decreased after the treatment with exogenous BMP-7. Furthermore, the Basso, Beattie, and Bresnahan (BBB) score reached 19.33 ± 0.58 in the BMP-7 + BMSC group at day 42. Nissl bodies in the model group were reduced compared to the sham group. After 42 days, in both the BMSC and BMP-7 + BMSC groups, the number of Nissl bodies increased. This is especially so for the number of Nissl bodies in the BMP-7 + BMSC group, which was more than that in the BMSC group. The expression of Tuj-1 and MBP in BMP-7 + BMSC group increased, whereas the expression of GFAP decreased. Moreover, the MEP waveform decreased significantly after surgery. Furthermore, the waveform was wider and the amplitude was higher in BMP-7 + BMSC group than that in BMSC group. BMP-7 promotes BMSC proliferation, induces the differentiation of BMSCsinto neuron-like cells, and inhibits the formation of glial scar. BMP-7 plays a confident role in the recovery of SCI rats. [ABSTRACT FROM AUTHOR]

Dark matter (DM) constitutes 85% of the matter in the Universe. However, its specific particle property is still unclear. The fundamentals of DM particles subject to gravitational interaction, and that the lepton excess in cosmic rays may originate from DM particles, inspired us to investigate DM particle properties beyond the standard model. We assume that a leptophilic SU(2) doublet exists in nature as the mediator connecting DM with visible leptons. Since general relativity is not renormalizable at the quantum level, it should be regarded as an effective field theory's leading order term. One species of the next-to-leading-order term should be operators linear to the Ricci scalar and containing scalar fields, such as the Higgs field, scalar DM, or the newly introduced SU(2) scalar doublet. These operators can cause DM annihilation through gravity portals. We analyzed constraints from the cosmic antiproton flux, DM relic abundance, cosmic positron flux, cosmic microwave background, and direct detection experiments. The result shows that there is a vast parameter space that is compatible with current experiments. DM with a mass of electroweak scale is only allowed to annihilate into leptons. We further show that the purely gravitational DM better explains the DArk Matter Particle Explorer cosmic lepton excess. Our work provides a promising mechanism for DM particles to connect with standard model particles. [ABSTRACT FROM AUTHOR]

Active regions (ARs) often possess an observed net electric current in a single magnetic polarity. We show that such “non-neutralized” currents can arise from a geometric projection effect when a twisted flux tube obliquely intersects the photosphere. To this end, we emulate surface maps of an emerging AR by sampling horizontal slices of a semi-torus flux tube at various heights. Although the tube has no net toroidal current, its poloidal current, when projected along the vertical direction, amounts to a significant non-neutralized component on the surface. If the tube emerges only partially as in realistic settings, the non-neutralized current will 1) develop as double ribbons near the sheared polarity inversion line, (2) positively correlate with the twist, and 3) reach its maximum before the magnetic flux. The projection effect may be important to the photospheric current distribution, in particular during the early stages of flux emergence. [ABSTRACT FROM AUTHOR]

Blackheart and soluble solids content (SSC) are critical parameters of pear for quality assessment and export trade guarantee. A non-destructive detection method was developed for measuring blackheart pear and SSC. Three discriminate analysis models, such as principal component analysis (PCA), correlation analysis and partial least square discriminate analysis (PLS-DA), were developed to identify black heart samples. Compared with PCA and correlation analysis, PLS-DA achieved the highest classification accuracy of 100% for identifying blackheart pears. Three sample sets of healthy samples, black heart ones, and their combination were applied to assess the performance of PLS model, and PLS model calibrated with healthy pears yielded better with root-mean-square errors of prediction 0.45°Brix. The overall results suggested that it was feasible to detect blackheart and SSC of pears simultaneously by online visible–NIR spectroscopy. [ABSTRACT FROM AUTHOR]

The quality of sunflower seed usually influences the load and product quality. The plumpness, expressing as the percent of the kernel and shell (%), is a crucial indicator reflecting the vigor of the sunflower seed. Investigations were carried out to measure the plumpness of intact sunflower seed by the use of terahertz (THz) transmittance imaging. The THz data of the worms, defects, and sound sunflower seeds were scanned using a THz time-domain transmittance imaging system. Followed THz imaging, the shell and kernel of the sample were separated carefully and recorded RGB images as the reference. Compared with the shell, the absorption coefficients and time domain signals of the kernel showed a significant difference in 0.5–2.0 THz. The characteristic images in 0.5–2.0 THz and control groups of 0.5–1.0, 1.0–1.5, and 1.5–2.0 THz were extracted, and the defects, kernel, and shell could be discriminated clearly in 0.5–2.0 THz. The models of the plumpness were developed between the THz and RGB images processed by the threshold segmentation. The determination coefficient and root mean square error of prediction (RMSEP) were 0.91 and 4% for an independent prediction set, respectively. The results suggested that use of THz transmittance imaging in measurement of plumpness of the intact sunflower seed was feasible. In addition, THz imaging provided a novel quality assessment solution for the coated samples. [ABSTRACT FROM AUTHOR]

Investigations were carried out to develop terahertz (THz) techniques combined with machine learning methods for rapidly measuring benzoic acid (BA) additive in wheat flour. The absorption coefficient had a significant characteristic peak at 1.94 THz, which usually varies with the increase of BA additive concentrations. Correlation analysis was initiated to choose a frequency pair of 1.94 and 1.86 THz that improved the predictive ability of multiple linear regressions (MLR) model. Then, quantitative determination models were modeled between BA concentrations and THz absorption coefficients using partial least square (PLS) regression and least square support vector machine (LS-SVM). Compared with MLR and PLS models, the LS-SVM model could be regarded as an effective tool for quality control of wheat flour with a correlation coefficient of prediction (Rp) of 0.994 and root mean square error of prediction (RMSEP) of 0.12%. The results suggest that combining THz spectroscopy with LS-SVM has the potential to quantitatively analyze BA additive in wheat flour. [ABSTRACT FROM AUTHOR]

Members of the WUSCHEL- related homeobox ( WOX) gene family encode plant-specific transcription factors that play key roles in controlling gene expression at all stages of plant development. In the present study, we isolated and characterized SpWOX13 (GenBank accession no. KJ713172), a member of the WOX gene family, from Stipa purpurea. Sequence and phylogenetic analyses showed that SpWOX13 belongs to an ancient clade of WOX genes. A subcellular localization analysis indicated that SpWOX13 localizes in the nucleus. The transcript levels of SpWOX13 were higher in young leaves and the vegetative apex than in other tissues of S. purpurea. Ectopic expression of SpWOX13 in Arabidopsis resulted in late flowering plants as these showed more rosette leaves. Histological analyses of the transgenic plants showed aberrant arrangements in the tunica cell layers of the shoot apical meristem. Scanning electron microscopy analyses revealed that the leaf pavement cells were larger in SpWOX13-overexpressing transgenic plants than in wild type. Our results suggest that SpWOX13 is involved in delaying and/or inhibiting cell differentiation. [ABSTRACT FROM AUTHOR]

The establishment of ad-abaxial polarity is an important characteristic of the development of lateral organs in plants. YABBY genes encode higher plant-specific nuclear proteins which play critical roles in promoting abaxial cell fate. IaYABBY2 ( IaYAB2, Genbank accession no. KF250432), isolated from Incarvillea arguta, is a member of YABBY gene family. Sequence characterization and phylogenetic analyses show that IaYABBY2 is a member of the YAB2 subfamily of Arabidopsis thaliana. Subcellular localization analysis indicates that IaYABBY2 is localized in the nucleus. Ectopic expression of IaYABBY2 in Arabidopsis plants resulted in the partial abaxialization of adaxial epidermises of leaves and sepals and development defect of florescence. The transgenic lines also showed higher level of anthocyanin content and photosynthesis capability after differential environment stress. These results indicate that the IaYABBY2 functions in the ad-abaxial polarity, development of shoot apical meristem, and environmental stress. [ABSTRACT FROM AUTHOR]

A novel and environmentally friendly heterogeneous catalyst has been prepared through the wet impregnation of copper(I) species onto the highly porous chitosan microspheres (CuI/PCMS). This novel CuI/PCMS heterogeneous catalyst with no additional ligands is much better than CuI homogeneous catalysts when applied in Heck reactions. Moreover, the reaction conditions are much milder than those for the similar copper catalysts mediated cross-coupling reactions reported in the literature. PCMS has been demonstrated not only the excellent solid support, but also have many unique functional groups to chelate the copper (I) species to enhance its catalytic activity. [ABSTRACT FROM AUTHOR]

In this paper, we study the approximation of the inversion of windowed Fourier transforms using Riemannian sums. We show that for certain window functions, the Riemannian sums are well defined on L(ℝ), 1 < p < ∞, and tend to the function to be reconstructed as the sampling density tends to infinity. [ABSTRACT FROM AUTHOR]

A novel multi-SOH functionalized ionic liquid is synthesized and a detailed account of its catalytic activities in acetalization and acetylation is given. The results showed that the ionic liquid is very efficient in the conventional acid-catalyzed reactions with good to excellent yields within a short reaction time. Operational simplicity, small amounts required, low cost of the catalyst, high yields, scalability and reusability are the key features of this methodology, which indicates the high potentialities of the novel ionic liquid to be used in environmentally friendly processes. [ABSTRACT FROM AUTHOR]

In this article, a finite element scheme for the family of time relaxation models, that represent a regularization of Navier-Stokes equations, is developed, analyzed and numerically tested. The proposed finite element scheme combines three ideas: (i) the use of an incompressible filter, for better consistency outside the periodic domains, (ii) a second order accurate linearization for the nonlinear term, that allows to solve only one linear system per time step, and (iii) a stabilization in time term that compliments well the linearization. A complete numerical analysis of the scheme, that includes the computability of its numerical solutions, its stability, and velocity error estimates, is given. This is followed by numerical experiments that confirm the theoretical convergence rates and show the advantage of the proposed scheme. [ABSTRACT FROM AUTHOR]

Marine object detection has become increasingly important in intelligent underwater robot. Because of color cast and blur in underwater images, features directly extracted from backbone networks usually lack interesting and discriminative characters, that affects performance on marine object detection. To this end, this paper proposes a novel refined marine object detector with attention-based spatial pyramid pooling networks and bidirectional feature fusion strategy to relieve the weakening of features and address marine object detection issues. Firstly, an attention-based spatial pyramid pooling network named as SA-SPPN is proposed to enrich interesting information and extend receptive field on original features extracted from backbone network. Based on enhanced multiple level features, the bidirectional feature fusion strategy is designed to fuse different level features and generate robust feature maps for detection. Specifically, the top-down connection could transfer semantic information from high-level features to enhance low-level features. The bottom-up pathway could extend resolution of high-level features. Furthermore, the cross-layer connections are integrated into both top-down passway and bottom-up passway to carry out multiple branch fusion. On bounding boxes regression phase, the distance-IoU loss is adopted to improve regression speed and accuracy. Finally, this paper conducts series experiments on underwater image datasets and URPC datasets to detect marine objects. The experimental results reveal that our approach could achieve impressive performance and reach 79.64% mAP on underwater image datasets, 79.31% mAP on URPC2019 datasets and 79.93% mAP on URPC2020 datasets, respectively. For standard object detection, the proposed algorithm also could realize notable performance and get 81.9% mAP on PASCAL VOC datasets. [ABSTRACT FROM AUTHOR]

The use of ceramic–metal laminated composites is an efficient way to improve the toughness of brittle ceramics. Uniform multilayered Al2O3–Ni laminated composites were prepared through a combined method of gel casting and hot pressing, which is less cumbersome than the traditional sequential lamination method. The wettability, diffusion and chemical reaction between Al2O3 and Ni were controlled through surface oxidation treatment of the Ni sheets. The results show that when the surface-oxidized Ni sheets were used, the microstructure of the Al2O3–Ni interface changed with the hot-pressing temperature. As the hot-pressing temperature was increased from 1150 to 1300 °C, a straight and clean interface formed, the interface became interlocked and, finally, a stable layer of NiAl2O4 formed at the interface. The interlocked microstructure was especially beneficial for interfacial bonding, and the plastic deformation of the Ni layers was restrained, thereby leading to slip steps rather than dimple formation on the fracture surfaces of the Ni layers. In addition, the toughening effects of plastic deformation and crack deflection in the Al2O3–Ni laminated composites were significant, which resulted in ductile fracture rather than brittle fracture. As a result, the Al2O3–Ni laminated composite that was prepared using the oxidized Ni sheets and the combined method of gel casting and hot pressing achieved a higher work of fracture than laminated composites that were prepared via other methods. [ABSTRACT FROM AUTHOR]

We study properties of waves of frequencies above the photospheric acoustic cut-off of ≈5.3 mHz, around four active regions, through spatial maps of their power estimated using data from the Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The wavelength channels 1600 Å and 1700 Å from AIA are now known to capture clear oscillation signals due to helioseismic p-modes as well as waves propagating up through to the chromosphere. Here we study in detail, in comparison with HMI Doppler data, properties of the power maps, especially the so-called “acoustic halos” seen around active regions, as a function of wave frequencies, inclination, and strength of magnetic field (derived from the vector-field observations by HMI), and observation height. We infer possible signatures of (magneto)acoustic wave refraction from the observation-height-dependent changes, and hence due to changing magnetic strength and geometry, in the dependences of power maps on the photospheric magnetic quantities. We discuss the implications for theories of p-mode absorption and mode conversions by the magnetic field. [ABSTRACT FROM AUTHOR]

The east–west component of the magnetic field, Bϕ, as observed in solar magnetograms containing quiet regions, is found to change its sign when the regions cross the central meridian. It is seen in both HMI/SDO and VSM/SOLIS full disk vector magnetograms. A mismatch between the calibrated line-of-sight and transverse fields is the reason for this hemispheric bias problem. Here mismatch means that one of the fields is either over-estimated or under-estimated. For HMI data, the transverse field is over-estimated. This mismatch is caused ultimately by a filling factor that is not precisely determined when unresolved structures are present. An updated inversion procedure for HMI observations, developed recently, is able to derive the filling factor with reasonable accuracy. The new data show that the hemispheric bias problem has been mitigated substantially. [ABSTRACT FROM AUTHOR]

Turnip is a member of the Brassica rapa species and is characterized by a swollen taproot that develops from the hypocotyl and part of the root. Gibberellins (GAs) are plant growth regulators involved in promoting cell elongation and play important roles in many aspects of plant growth and development. Interestingly, exogenous application of GA3 was found to significantly inhibit taproot formation in turnip. Moreover, endogenous GA contents decreased during the early developmental stages of taproot formation, suggesting that GA plays a negative role in taproot formation. We examined the anatomical structure of the taproot and found that lignification of the xylem cell wall was enhanced after treatment with GA3. Yeast two-hybrid assays suggested the occurrence of protein interactions between DELLAs and NACs in turnip. We also found that the expression of NAC-targeted genes involved in lignification of the secondary cell wall was significantly upregulated upon GA3 treatment. Taken together, these results supported the hypothesis that GA induced DELLA proteins degradation to release NAC proteins and induced xylem lignification, therefore inhibiting taproot formation, providing new insight into the molecular mechanism underlying turnip taproot formation. [ABSTRACT FROM AUTHOR]

The safety of milk powder is closely related to everyone's life. In the production of milk powder, it is often easy to mix in foreign bodies, such as light and thin plastic, insects, metals, and other foreign bodies. In this paper, THz spectroscopy is used to detect common foreign bodies in milk powder, such as polymer materials (i.e., PP, PVC, and PE), insects, and metal gaskets. The detection of foreign bodies in milk powder can be realized by using THz spectroscopy combined with random forest discrimination method, and the recognition accuracy rate reaches 100%. The accuracy rate also reaches 100% when the types of foreign bodies are distinguished, thus, successfully realizing the identification and qualitative discrimination of foreign bodies in milk powder. At the same time, THz imaging technology is used to detect milk powder with foreign bodies. The outline and the boundaries of foreign bodies in milk powder are clear in the imaging from 0.5 to 1.0 THz. Thus, the size and shape of foreign bodies in milk powder can be well distinguished. This experiment verifies the feasibility of qualitative detection of foreign bodies in milk powder by the combination of terahertz imaging and spectrum, and established a better random forest detection model, which proposes a solution to ensure the safety of milk powder. [ABSTRACT FROM AUTHOR]

Macro-porous alumina ceramics were prepared by the gel-casting method using sacrificial polystyrene spheres as the template. The resulted porous alumina ceramics have regularly arranged pores and high cell wall densities, which confer high mechanical strength to the porous ceramics. The highest compressive strength for a porous alumina ceramic, with a relative density of 30%, in this work is 28 MPa, which is at least 74% higher than that of previously reported porous alumina ceramics with the same porosity. The results show that the cell wall density, window size and cell size can be adjusted by controlling the sintering temperature, solid loading percentage of the alumina slurry and the size of the polystyrene spheres. With the increase in cell wall density and decrease in cell size and window size, the compressive strength of the porous alumina increases. Thus, a novel porous structure with high porosity and high strength can be made by this flexible method which is also suitable for making complicated shapes and large sizes. [ABSTRACT FROM AUTHOR]

Key message: SpERF1 acts as a positive regulator, contributing to drought stress tolerance in A. thaliana through activating DRE/CRT elements in the promoters of abiotic stress-responsive genes. Abstract: Stipa purpurea is an endemic perennial grass species in alpine arid and semi-arid meadows on the Qinghai-Xizang Plateau, which is highly tolerant against drought and cold. ERF transcription factors are known to regulate gene expression under abiotic and biotic treatments. Herein, we isolated a full-length ERF gene CDS from S. purpurea named SpERF1, which was induced by drought, cold, and jasmonic acid stresses. Subcellular localization revealed that SpERF1 is a nuclear protein, consistent with its roles as a transcription factor. Overexpression of SpERF1 enhanced drought tolerance of transgenic Arabidopsis thaliana via the activation of DRE/CRT elements in the promoters of abiotic stress-responsive genes. Furthermore, increased accumulation of proline indicated that SpERF1 might be involved in proline synthesis in the transgenic lines, allowing them to have a better buffering capacity and membrane protection under drought stress. This study indicated that SpERF1 might be an attractive target in the genetic engineering for improving stress tolerance in other crops. Moreover, SpERF1 protein function analysis increased our understanding of S. purpurea's ability to adapt to the adverse conditions of the Qinghai-Xizang Plateau. [ABSTRACT FROM AUTHOR]

The conventional transcatheter closure of patent ductus arteriosus (PDA) requires femoral artery puncture and angiography for duct anatomic and shunting estimation. If such estimation can be replaced by transthoracic echocardiography (TTE), the procedure will be further simplified, with fewer invasions. This study aimed to examine whether TTE can serve as an alternative to aorta angiography and as a major guidance for transcatheter duct closure. The study enrolled 298 consecutive patients (71 males and 227 females) with PDA. In the study, TTE with combined two-dimensional echocardiography (2DE) imaging and color-coded flow imaging (CDFI) was performed to measure the minimal shunting width (MSW) as the estimated minimal duct size for selection of an Amplatzer duct occluder (ADO) and to monitor the transcatheter duct closure intraprocedurally. The MSW was validated against the duct-stretched diameter (SDD), against the minimal waist diameter of the conical part of a released occluder measured by X-ray spot picture after successful duct closure (SDC), and against the size of the finally used ADO (SADO). Good correlation was found between MSW and SDD [SDD (mm) = 1.31 MSW; r = 0.89; p < 0.01] and between MSW and SADO [SADO (mm) = 1.71 MSW; r = 0.88; p < 0.01]. Of 296 patients who received occlusion using MSW as the reference for selection of the occluder, SDC was attained in 288 (97.3 %), 5 (1.7 %), and 2 (0.7 %) patients, respectively, at the first, second (1 ADO replacement), and third (2 ADO replacements) occluding attempt. Acute occluder dislodgement occurred in one patient (0.3 %). At the 12-month follow-up assessment, no major complications were found, and the total immediate or 12-month SDC was 99.7 %. Echocardiography as an alternative major guidance to angiography for transcatheter duct closure is technically feasible, and TTE guidance can further simplify the procedure, with fewer invasions and potential complications. [ABSTRACT FROM AUTHOR]

The Helioseismic and Magnetic Imager (HMI) began near-continuous full-disk solar measurements on 1 May 2010 from the Solar Dynamics Observatory (SDO). An automated processing pipeline keeps pace with observations to produce observable quantities, including the photospheric vector magnetic field, from sequences of filtergrams. The basic vector-field frame list cadence is 135 seconds, but to reduce noise the filtergrams are combined to derive data products every 720 seconds. The primary 720 s observables were released in mid-2010, including Stokes polarization parameters measured at six wavelengths, as well as intensity, Doppler velocity, and the line-of-sight magnetic field. More advanced products, including the full vector magnetic field, are now available. Automatically identified HMI Active Region Patches (HARPs) track the location and shape of magnetic regions throughout their lifetime. The vector field is computed using the Very Fast Inversion of the Stokes Vector (VFISV) code optimized for the HMI pipeline; the remaining 180 azimuth ambiguity is resolved with the Minimum Energy (ME0) code. The Milne-Eddington inversion is performed on all full-disk HMI observations. The disambiguation, until recently run only on HARP regions, is now implemented for the full disk. Vector and scalar quantities in the patches are used to derive active region indices potentially useful for forecasting; the data maps and indices are collected in the SHARP data series, hmi.sharp_720s. Definitive SHARP processing is completed only after the region rotates off the visible disk; quick-look products are produced in near real time. Patches are provided in both CCD and heliographic coordinates. HMI provides continuous coverage of the vector field, but has modest spatial, spectral, and temporal resolution. Coupled with limitations of the analysis and interpretation techniques, effects of the orbital velocity, and instrument performance, the resulting measurements have a certain dynamic range and sensitivity and are subject to systematic errors and uncertainties that are characterized in this report. [ABSTRACT FROM AUTHOR]

A portable near-infrared (NIR) device was developed to nondestructively predict Brix value in intact 'Gannan' navel oranges. This research focused on developing calibration models which were less disturbed by the challenges of portable applications. The spectra of 150 samples were collected in the wavelength range of 820-950 nm. Wavelet transformed (WT) was applied to compress the raw data for improving the optimization efficiency. Classical linear partial least squares regression and nonlinear least squares support vector regression (LSSVR) were applied to building calibration models. By comparison, both prediction precision and optimization efficiency of the compressed regression models were improved. The LSSVR models outperformed the PLS models with higher accuracy and lower error. LSSVR combined with WT compression (WT-LSSVR) produced the best correlation coefficient value ( r) and the root mean squared error of prediction of 0.918 and 0.321 Brix. Based on these results, WT-LSSVR is to be a promising method to improve precision and optimization efficiency of NIR spectral calibration models for Brix prediction in 'Gannan' navel oranges by the portable near-infrared device. [ABSTRACT FROM AUTHOR]