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Effects of Melatonin on Growth, Physiology and Gene Expression in Rice Seedlings Under Cadmium Stress
No full textMelatonin (MLT) is a hormonal substance found in many organisms and can improve plant stress resistance. In this study, the japonica rice variety Y32 and indica rice variety NJ6 were cultivated in hydroponics under different concentrations of CdCl2 at the two-leaf stage. The growth, physiological and biochemical responses of the seedlings and the expression of cadmium (Cd)-related genes under exogenous melatonin (MLT) treatment were assessed. The results indicated that Cd stress destroyed the dynamic balance between reactive oxygen species (ROS) production and removal, resulting in ROS accumulation, membrane lipid peroxidation, and impaired growth and development. Following the application of exogenous MLT to rice seedlings, increases in plant biomass including both underground and above-ground areas were observed. MLT also scavenged the inhibition of superoxide dismutase (SOD) and peroxidase (POD) in a concentration dependent manner in response to Cd stress. Catalase (CAT) activity and malondialdehyde (MDA) expression also decreased following MLT treatment. Amongst the six Cd-related genes assessed, five genes were down-regulated and one was up-regulated in response to MLT treatment. Taken together, these data demonstrate that MLT improves the resilience of rice seedlings at the biochemical, physiological, and molecular levels, and diminishes the damage caused by Cd stress
Influence of Plant Growth Promoting Rhizobacterial Inoculation on Wheat Productivity Under Soil Salinity Stress
No full textSoil salinity affects the growth and yield of crops. The stress of soil salinity on plants can be mitigated by inoculation of plant growth promoting bacteria (PGPR). The influence of PGPR inoculation on wheat (Triticum aestivum L.) crop productivity under salinity stress has not been properly addressed so far. Therefore, the present study was conducted to investigate the effects of various PGPR strains (W14, W10 and 6K; alone and combined) at several growth attributes of wheat plant under different soil salinity gradients (3, 6 and 9 dS m-1). The growth attributes of wheat (height, roots, shoots, spikes, grains quality, biological and economical yield, nutrients nitrogen, phosphorus and potassium in grains) were highly affected by salinity and decreased with increasing salinity level. The PGPR inoculation substantially promoted growth attributes of wheat and prominent results were observed in W14 × W10 × 6K treatment at all salinity levels. The results suggest that inoculation of PGPR is a potential strategy to mitigate salinity stress for improving wheat growth and yield
Dynamics of the Moving Ring Load Acting in the System “Hollow Cylinder + Surrounding Medium” with Inhomogeneous Initial Stresses
No full textThis paper studies the influence of the inhomogeneous initial stress state in the system consisting of a hollow cylinder and surrounding elastic medium on the dynamics of the moving ring load acting in the interior of the cylinder. It is assumed that in the initial state the system is compressed by uniformly distributed normal forces acting at infinity in the radial inward direction and as a result of this compression the inhomogeneous initial stresses appear in the system. After appearance of the initial stresses, the interior of the hollow cylinder is loaded by the moving ring load and so it is required to study the influence of the indicated inhomogeneous initial stresses on the dynamics of this moving load. This influence is studied with utilizing the so-called three-dimensional linearized theory of elastic waves in elastic bodies with initial stresses. For solution of the corresponding mathematical problems, the discrete-analytical solution method is employed and the approximate analytical solution of these equations is achieved. Numerical results obtained within this method and related to the influence of the inhomogeneous initial stresses on the critical velocity of the moving load and on the response of the interface stresses to this load are presented and discussed. In particular, it is established that the initial inhomogeneous initial stresses appearing as a result of the action of the aforementioned compressional forces cause to increase the values of the critical velocity of the moving load
Cryptanalysis and Improvement of a Chaotic Map-Control-Based and the Plain Image-Related Cryptosystem
No full textDue to the characteristics of chaotic systems, different cryptosystems based on chaos have been proposed to satisfy the security of multimedia data. A plain image-related chaotic algorithm is proposed by Luo et al. with high speed and efficiency. Security weaknesses of the cryptosystem are studied in this paper. It is found that the important secret key information is leaked because an important parameter can be obtained after an inverse operation in the last step of the cryptosystems without secret key. Meanwhile, the value zero is processed improperly in quantification algorithm. Based on the weaknesses, chosen plaintext attack on the cryptosystem is proposed, by which, an important parameter, equivalent to secret key, can be calculated with a specific chosen plain image. With the obtained parameter, the plain image of any ciphered image, encrypted by the cryptosystem, can be recovered. Then, an improvement is proposed to solve the problems after modifying the quantification algorithm. It is from the experiments that chosen plaintext attack is valid and improved algorithm possesses better performance
The Topology Sampling of H2SO4·NH3 with Meta-Dynamics Method
No full textThe configurations of molecular clusters have significant impacts on their growth into fine particles in atmosphere. In this paper, we explore the topology space of the structure of H2SO4·NH3 dimer with a novel sampling technique of meta-dynamics (MTD) method and ab initio molecular dynamics simulations. The simulations are carried out at the temperatures of both 50 K and 242 K, which represent the typical high and low latitudes of troposphere. The results show that, compared with only traditional MD simulations, the structure samplings are significantly accelerated with MTD method. Therefore, more isomers of the dimer are discovered within the same simulation time scale. In addition, the results show that MTD is more efficient for circumstances with high temperature
Deep Feature Fusion Model for Sentence Semantic Matching
No full textSentence semantic matching (SSM) is a fundamental research in solving natural language processing tasks such as question answering and machine translation. The latest SSM research benefits from deep learning techniques by incorporating attention mechanism to semantically match given sentences. However, how to fully capture the semantic context without losing significant features for sentence encoding is still a challenge. To address this challenge, we propose a deep feature fusion model and integrate it into the most popular deep learning architecture for sentence matching task. The integrated architecture mainly consists of embedding layer, deep feature fusion layer, matching layer and prediction layer. In addition, we also compare the commonly used loss function, and propose a novel hybrid loss function integrating MSE and cross entropy together, considering confidence interval and threshold setting to preserve the indistinguishable instances in training process. To evaluate our model performance, we experiment on two real world public data sets: LCQMC and Quora. The experiment results demonstrate that our model outperforms the most existing advanced deep learning models for sentence matching, benefited from our enhanced loss function and deep feature fusion model for capturing semantic context
Study of phylogenic relationships of some wild and crop species of Iranian <i>Crocus</i> by ITS nuclear loci
No full textITS (Internal Transcription Spacer of nuclear ribosomal DNA) regions method was applied to identify and
study the phylogenetic relationships existing between 41 individuals of Crocus, including 8 species collected in Iran (4
crop and 8 wild individuals) and 16 species (2 crop and 27 wild individuals) already registered in GenBank (NCBI).
PCR amplifications were performed using the primer designed on the nucleotide sequence of nuclear region (ITS).
A total of 12 sequences were obtained and registered in NCBI database. In particular, 4 of these sequences were not
already present in the scientific library. Nucleotide polymorphic sites were counted for ITS (N = 97). The results showed
that, the Cytosine base is the most abundant nucleotide. Relatively high conservation was observed in the ITS regions
of the populations (0.761). Each sample could be distinguished from the others in the phylogenic trees developed
based on the data obtained by ITS barcode genes. In general, ITS sequence indicating high resolution at the species
level is very suitable for phylogenetic studies in the Crocus family. Phylogenetic analysis demonstrated the genetic
relationship between crop saffron and wild Crocus species. According to the results of this study, the wild species of C.
cartwrightianus and C. oreocreticus were considered as the closest relatives of the saffron. The results of the study also
indicated that, the different ecotypes of C. sativus may have evolved through independent events probably due to the
geographic and environmental pressure
Circumferential variation in mechanical characteristics of porcine descending aorta
No full textArterial characterization of healthy descending thoracic aorta (DTA) is indispensable in determining stress
distributions across wall thickness and different regions that may be responsible for aorta inhomogeneous dilation,
rupture, and dissection when aneurysm occurs. Few studies have shown the inhomogeneity of DTA along the aorta
tree considering changes in circumferential direction. The present study aims to clarify the circumferential regional
characterization of DTA. Porcine DTA tissues were tested according to region and orientation using uniaxial tension.
For axial test, results show that the difference in circumferential direction was mainly in collagen fiber modulus, where
the anterior collagen fiber modulus was significantly lower than the posterior quadrant. For circumferential test, the
difference in circumferential direction was mainly in the recruitment parameter, where the circumferential stiffness is
significantly higher in the posterior region at physiological maximum stress. The proximal posterior quadrant and left
quadrant showed significantly lower axial collagen fiber stiffness than the right and anterior quadrants, which may be
a factor in aneurysm development. Furthermore, the constitutive parameters for similar detailed regions can be used
by biomedical engineers to investigate improved therapies and thoroughly understand the initial stage of aneurysm
development. The regional collagen fiber modulus can help improve our understanding of the mechanisms of arterial
dilation and aortic dissection
Stability Analysis of Transfer Alignment Filter Based on the μ Theory
Get PDFThe performance of the transfer alignment has great impact on inertial navigation systems. As the transfer alignment is generally implemented using a filter to compensate the errors, its accuracy, rapidity and anti-disturbance capability are key properties to evaluate the filtering process. In terms of the superiority in dealing with the noise, H∞ filtering has been used to improve the anti-disturbance capability of the transfer alignment. However, there is still a need to incorporate system uncertainty due to various dynamic conditions. Based on the structural value theory, a robustness stability analysis method has been proposed for the transfer alignment to evaluate the impact of uncertainty on the navigation system. The mathematical derivation has been elaborated in this paper, and the simulation has been carried out to verify the effectiveness of the algorithm
A Robust Image Watermarking Scheme Using Z-Transform, Discrete Wavelet Transform and Bidiagonal Singular Value Decomposition
Get PDFWatermarking is a widely used solution to the problems of authentication and copyright protection of digital media especially for images, videos, and audio data. Chaos is one of the emerging techniques adopted in image watermarking schemes due to its intrinsic cryptographic properties. This paper proposes a new chaotic hybrid watermarking method combining Discrete Wavelet Transform (DWT), Z-transform (ZT) and Bidiagonal Singular Value Decomposition (BSVD). The original image is decomposed into 3-level DWT, and then, ZT is applied on the HH3 and HL3 sub-bands. The watermark image is encrypted using Arnold Cat Map. BSVD for the watermark and transformed original image were computed, and the watermark was embedded by modifying singular values of the host image with the singular values of the watermark image. Robustness of the proposed scheme was examined using standard test images and assessed against common signal processing and geometric attacks. Experiments indicated that the proposed method is transparent and highly robust