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The Quality Assessment of Non-Integer-Hour Data in GPS Broadcast Ephemerides and Its Impact on the Accuracy of Real-Time Kinematic Positioning Over the South China Sea
No full textAbnormal effects in GPS broadcast ephemerides can have a significant effect on real-time navigation and positioning solutions that use the orbit and clock error data provided by GPS broadcast ephemerides. This paper describes three types of non-integer-hour navigation data in GPS broadcast ephemeris data. Compared with GPST integer hour data, we find that there are two types of data blocks for non-integer-hour navigation containing gross errors with different levels of precision, which is reflected in the user range accuracy (URA) of the broadcast ephemeris. These gross errors can cause large deviations when using the GPS broadcast ephemeris for orbit calculation and lead to a decrease in the kinematic positioning accuracy. An improved weighting method which is based on the consistency relationship between the URA value and the orbital precision is proposed to improve the positioning accuracy by controlling the effect of gross errors in the broadcast ephemerides. The correction algorithm proposed in this paper was applied to real-time kinematic positioning with shipborne GPS data over the South China Sea. The results showed that the proposed positioning algorithm can effectively reduce the effects of gross errors in the broadcast ephemeris, and significantly improve the accuracy of the navigation and positioning
Effect of Recycling Cycles on the Mechanical and Damping Properties of Short Alfa Fibre Reinforced Polypropylene Composite
No full textThis paper aims at studying the effect of recycling on the static and dynamic properties of short alfa fibre reinforced polypropylene. For this purpose, alfa fibres reinforced composites were elaborated by an injection moulding process and were subjected to different mechanical recycling cycles. Then, non-recycled and recycled materials were subjected to static tests and Dynamic Mechanical Analysis (DMA) to evaluate the effect of recycling on their behaviour. Besides, the effects of alkali and salt water treatments on the static and dynamic properties of the alfa composite were also investigated. The obtained results show that tensile and flexural properties of alfa fibres reinforced composites decrease during recycling cycles. Moreover, the recycling induces a drop in the storage modulus and enhances the loss factor of these composites. The composites with alfa fibre especially the alkali treated composite show the same resistance to recycling as composites with hemp fibres. Further, SEM observations indicate a decrease in the fibres dimension with the recycling cycles, especially for alfa fibres, which can explain the decrease in the properties of the alfa composite during recycling operations
Prenatal exposure to the fluoride containing psychiatric drug fluoxetine and anti-oxidative alterations in the neonatal rat brain
No full textFluoride is a key ingredient of many psychiatric drugs like fluoxetine (Prozac®, Fluoxetine®). Pregnant women
frequently use this drug as they suffer from depression and anxiety disorders during this period. Fluoxetine is able to
reach the fetus through the placenta and passes to the newborn through milk. In the present study, female Wistar rats
were treated with 5, 10, and 20 mg/L fluoxetine (containing 94% fluorides) from pregnancy day 10 to day 20. After
delivery, the levels of the enzymatic antioxidants in the brain of their offspring at postnatal day 2 were measured. The
results showed that, in all fluoxetine exposed groups compared with the control group, there was a significant decrease
(P P >
0.05) in the activity of malondialdehyde and creatine kinase. The results suggest that fluoxetine may be a developmental
neurotoxicant due to presence of fluoride hence must be used carefully during pregnancy
Trace Elements in the Soil-Plant Systems of Copper Mine Areas-A Case Study From Murgul Copper Mine From the Black Sea Region of Turkey
No full textThis study presents a case study on the heavy metal analysis of soil and plant samples around the Murgul copper mine, one of the first and most important mining areas in Turkey. An attempt has been made to investigate the status of trace elements like Al3+, Fe2+, Cu2+, Zn2+, Pb2+, Ni2+, Co2+ and Cd2+ in soils and plants. The sampling localities were taken from 500 m, 600 m, and 1000 m altitudes around the factory and at 1400 m in the forest zone. The aboveground parts and foliage ash of Silene compacta, Tussilago farfara, Smilax excelsa, Rhododendron ponticum, R. luteum, and herbal mix were analysed. The results of analysis have revealed the minimum and maximum concentrations measured in the plants as follows; aluminium (20-8985 mg kg-1), cadmium (0.0-0.5 mg kg-1), cobalt (0.0-5.5 mg kg-1), copper (0.0-347.5 mg kg-1), iron (25-9320 mg kg-1), lead (2-51 mg kg-1), nickel (1.5-16.5 mg kg-1), and zinc (13.0-221.0 mg kg-1). In the soil the concentrations of aluminium, cadmium, cobalt, copper, iron, lead, nickel, and zinc vary between 33-457, 0.0-0.0, 0.0-0.4, 0.1-88.7, 14-50, 0.3-4.1, 0.2-0.8, and 4.0-20.3 mg kg-1 respectively. These findings enlighten the fact that copper is generally toxic in the soils as well as plants. Silene compacta has been recorded as a high copper accumulator, behaving as a healthy plant on the polluted sites of the area alongside the Murgul creek (especially at 600 m). This study stresses the fact that it is imperative to assess and monitor the levels of heavy metals in the environment due to anthropogenic activities, including mining, for evaluation of human exposure and for sustainable environment
Cloning and characterization of 66 kDa streptavidin-binding peptides (SBP) of <i>Pisum sativum</i> L. embryo specific to var. Alaska
No full textThe aim of the current research was to clone and to characterize the partial 66 kDa streptavidin-binding
peptide (SBP) found in the germinated embryos of Pisum sativum L. var. Alaska. The pea (P. sativum var. Alaska)
embryos possess prominent 66 kDa SBPs that gradually disappeared after few hours of germination in germinated
embryos, but not in the cotyledons. The total RNA was isolated from embryos of P. sativum but could not be isolated
from the cotyledons. The partial nucleotides sequences of 66 kDa SBPs of embryonic stalk (P. sativum var. Alaska) were
cloned and identified using pMOSBlue vector. 66 kDa (SBP) gene from the embryos of P. sativum var. Alaska possesses
327 bp having an open reading frame (ORF) region in a part of the gene that encoded for 108 amino acids. Alignment
showed similarity among 66 kDa SBPs P. sativum var. Alaska, with P. sativum seed biotinylated protein (SBP65) and P. sativum sbp65a mRNA with DNA distance matrix between 0.0094 to 1.2676. MALDI-TOF mass spectrometry analysis
of 66 kDa (SBP) proteins showed it had similar short peptides to 19 proteins found in different organisms, especially Convicilin precursor, and the seed biotinylated protein in P. sativum. The alignment results of both nucleotide sequences
and amino acid residues either from cloning or MALDI-TOF-MS showed differences with related species, especially P. sativum. No mRNA was found in the cotyledons during seeds germination, which means no metabolic activities and
this part may act only as food reservoirs for growing newly embryos
Geek Talents: Who are the Top Experts on GitHub and Stack Overflow?
No full textIn the field of Computer Science, software developers need to use a wide array of social collaborative platforms for learning and cooperating. The most popular ones are GitHub and Stack Overflow. Existing platforms only support search queries to extract relevant repository information from GitHub, or questions and answers from Stack Overflow. This ignores the valuable coder-related part-who are the top experts (geek talents) in a specific area? This information is important to companies, open source projects, and to those who want to learn from an expert role model. Thus, how to find the right developers is quite a crucial yet challenging problem. Most of the current works mainly focus on recommending experts in a particular software engineering task and ignore the relationship between developers within different projects. In this paper, we propose a novel technique that automatically identifies geek talents from GitHub, Stack Overflow, and across both communities. The results show that our work performs well at recommending proper developers in diverse areas
Comprehensive Analysis of Secure Data Aggregation Scheme for Industrial Wireless Sensor Network
No full textAs an Industrial Wireless Sensor Network (IWSN) is usually deployed in a harsh or unattended environment, the privacy security of data aggregation is facing more and more challenges. Currently, the data aggregation protocols mainly focus on improving the efficiency of data transmitting and aggregating, alternately, the aim at enhancing the security of data. The performances of the secure data aggregation protocols are the trade-off of several metrics, which involves the transmission/fusion, the energy efficiency and the security in Wireless Sensor Network (WSN). Unfortunately, there is no paper in systematic analysis about the performance of the secure data aggregation protocols whether in IWSN or in WSN. In consideration of IWSN, we firstly review the security requirements and techniques in WSN data aggregation in this paper. Then, we give a holistic overview of the classical secure data aggregation protocols, which are divided into three categories: hop-by-hop encrypted data aggregation, end-to-end encrypted data aggregation and unencrypted secure data aggregation. Along this way, combining with the characteristics of industrial applications, we analyze the pros and cons of the existing security schemes in each category qualitatively, and realize that the security and the energy efficiency are suitable for IWSN. Finally, we make the conclusion about the techniques and approach in these categories, and highlight the future research directions of privacy preserving data aggregation in IWSN
A Novel Robust Watermarking Algorithm for Encrypted Medical Image Based on DTCWT-DCT and Chaotic Map
No full textIn order to solve the problem of patient information security protection in medical images, whilst also taking into consideration the unchangeable particularity of medical images to the lesion area and the need for medical images themselves to be protected, a novel robust watermarking algorithm for encrypted medical images based on dual-tree complex wavelet transform and discrete cosine transform (DTCWT-DCT) and chaotic map is proposed in this paper. First, DTCWT-DCT transformation was performed on medical images, and dot product was per-formed in relation to the transformation matrix and logistic map. Inverse transformation was undertaken to obtain encrypted medical images. Then, in the low-frequency part of the DTCWT-DCT transformation coefficient of the encrypted medical image, a set of 32 bits visual feature vectors that can effectively resist geometric attacks are found to be the feature vector of the encrypted medical image by using perceptual hashing. After that, different logistic initial values and growth parameters were set to encrypt the watermark, and zero-watermark technology was used to embed and extract the encrypted medical images by combining cryptography and third-party concepts. The proposed watermarking algorithm does not change the region of interest of medical images thus it does not affect the judgment of doctors. Additionally, the security of the algorithm is enhanced by using chaotic mapping, which is sensitive to the initial value in order to encrypt the medical image and the watermark. The simulation results show that the pro-posed algorithm has good homomorphism, which can not only protect the original medical image and the watermark information, but can also embed and extract the watermark directly in the encrypted image, eliminating the potential risk of decrypting the embedded watermark and extracting watermark. Compared with the recent related research, the proposed algorithm solves the contradiction between robustness and invisibility of the watermarking algorithm for encrypted medical images, and it has good results against both conventional attacks and geometric attacks. Under geometric attacks in particular, the proposed algorithm performs much better than existing algorithms
Association between preterm birth risk and polymorphism and expression of the DNA repair genes <i>OGG1</i> and <i>APE1</i> in Saudi women
No full textGenomic instability and mutations caused by increases in oxidative stress during pregnancy
can damage the fetoplacental unit and can upshot preterm birth. Oxidative damage to DNA may possibly
be involved in etiology of preterm birth (PTB) which can be repaired by DNA repair gene. In the present
study, we assessed the association of base excision repair gene family by analyzing the association of
single nucleotide polymorphisms and genes expression in 8-oxoguanine glycosylase-1 (OGG1) and
apurinic-apyrimidinic endonuclease 1 (APE1) genes with risk of preterm birth in Saudi women. We
analyzed genotypes of four single nucleotide polymorphisms (SNPs) (rs1052133, rs293795, rs2072668 and
rs2075747) in OGG1 gene and three SNPs (rs1130409, rs3136814, and rs3136817) in APE1 gene using
TaqMan Genotyping assay kits in 50 pairs of preterm cases and individually matched controls. Also, gene
expression level was explored by RT-PCR in 10 pairs of preterm placental tissues and individually matched
normal placental tissues. Two OGG1 SNP, rs1052133 (OR=0.497; c2=1.11; p=0.292) and rs2072668
(OR=0.408; c2=1.90; p=0.167) and one APE1 SNP rs3136817 (OR=0.458; c2=0.40; p=0.527) showed nonsignificant protective effect against PTB development. The expression of both genes under study was
found lower in the PTB patients. Genotype and allele frequencies of both gene SNPs did not show any
association with the risk of preterm delivery in Saudi women (P˃0.05). However, synthesis and release of
OGG1 and APE1 proteins decreased in preterm placental tissues compared to term delivery reflects the
probability of being one of the mechanisms leading to preterm birth
Suspension state promotes extravasation of breast tumor cells by increasing integrin β1 expression
No full textMechanical microenvironment can strongly affect the metastatic efficiency of circulating
tumor cells. However, the effect of suspension state on their extravasation and the mechanisms involved
are still unclear. To explore the influence of suspension state on extravasation (including adhesion,
spreading and transendothelial migration) of breast tumor cells and its relevant molecular mechanism,
MDA-MB-231 cells were cultured on poly (2-hydroxyethyl methacrylate) coated 6-well plates to minic
the suspension state. Suspension state promoted adhesion, spreading and transendothelial migration
of MDA-MB-231 cells to EAhy926 endothelial cells (ECs) monolayer under both the static condition
and 0.5 dyne/cm2
flow shear stress (FSS). The number of cells adhered to ECs monolayer reached 2.15
(static condition, 3 d) and 1.67 (FSS, 3 d) times, and the number of migration reached 10.60 times,
respectively, as compared to that in adhesion state. Moreover, MDA-MB-231 cells knockdown of
integrin β1 provoked poor adhesion and transendothelial migration, as compared with MDA-MB-231
cells. But it made no difference in cell spreading. Our results implied the increasing expression of
integrin β1 induced by suspension culture promoted the adhesion and transendothelial migration of
MDA-MB-231 cells, but had no significant influence on their spreading