429 research outputs found
Ergodic channel capacity of PPM-coded optical MIMO communications under combined effects
The ergodic channel capacity of wireless optical multiple-input multiple-output (MIMO) system with pulse position modulation (PPM) is investigated. The combined effects of atmospheric turbulence, atmospheric attenuation, pointing error and channel spatial correlation are taken into consideration. The expression of ergodic channel capacity is derived, and is further performed by Wilkinson approximation method for simplicity. The simulation results indicated that the strong spatial correlation has the greatest influence on the ergodic channel capacity, followed by pointing errors and atmospheric turbulence. Moreover, the ergodic channel capacity growth brought by space diversity only performs well under independent and weakly correlated channels. Properly increasing the size and spacing of the receiving apertures is an effective means of effectively increasing the ergodic channel capacity
Ergodic channel capacity of PPM-coded optical MIMO communications under combined effects
The ergodic channel capacity of wireless optical multiple-input multiple-output (MIMO) system with pulse position modulation (PPM) is investigated. The combined effects of atmospheric turbulence, atmospheric attenuation, pointing error and channel spatial correlation are taken into consideration. The expression of ergodic channel capacity is derived, and is further performed by Wilkinson approximation method for simplicity. The simulation results indicated that the strong spatial correlation has the greatest influence on the ergodic channel capacity, followed by pointing errors and atmospheric turbulence. Moreover, the ergodic channel capacity growth brought by space diversity only performs well under independent and weakly correlated channels. Properly increasing the size and spacing of the receiving apertures is an effective means of effectively increasing the ergodic channel capacity
Anticonvulsant and sedative effect of Fufang Changniu pills and probable mechanism of action in mice
Purpose: To investigate the anticonvulsant and sedative effects of Fufang Changniu Pills (FCP) and its probable mechanism of action in mice.Methods: The water decoction of FCP was prepared and the main constituents were determined by high performance liquid chromatography (HPLC). The anticonvulsant activities of FCP were evaluated by maximal electroshock (MES) and pentylenetetrazole (PTZ)-induced seizures in mice. Pentobarbital sodium-induced sleeping time and locomotor activity measurements were performed to evaluate the sedative effects of FCP in mice. Finally, PTZ-induced chronic seizures were established, and expressions of gamma-aminobutyric acid A receptor (GABA-A) and glutamic acid decarboxylase 65 (GAD65) in the brains of the mice were assayed by western blot in order to explore the probable mechanisms of action of the drug.Results: Gallic acid, liquiritin, cinnamyl alcohol, cinnamic acid and glycyrrhizic acid were detected in FCP decoction. FCP (50, 100 and 200 mg/kg) showed significant anticonvulsant and sedative effects on epileptic mice induced by MES (p < 0.05) and PTZ (p < 0.05). Moreover, pentobarbital sodium-induced sleeping time and locomotor activity tests showed that FCP possesses sedative effect (p < 0.05). Western blot data indicate that FCP significantly up-regulated GABA-A and GAD 65 in the brains of chronic epileptic rats (p < 0.05).Conclusion: FCP has significant anticonvulsant and sedative effects, and the mechanism of its action may be related to the up-regulation of GABA-A and GAD 65 in mice brain.Keywords: Epilepsy, Fufang Changniu pills, Anticonvulsant, Sedative effect, Gamma-aminobutyric acid, Glutamate dehydrogenas
Relationship between Extraversion and Employeesâ Innovative Behavior and Moderating Effect of Organizational Innovative Climate
This paper aims to clarify the relationship between extraversion and employeesâ innovative and disclose the
moderating effect of organizational innovative climate on that relationship. To this end, 300 employees were selected from various enterprises in three Chinese cities, and subjected to a questionnaire survey based on the five factor model (FFM) and 5-point Likert scale. Through statistical regressions, the author explored the effects of extraversion and organizational innovative climate have on employeesâ innovative behavior. Then, the organizational innovative climate was divided into five dimensions, and the feature activation theory was implemented to reveal the moderating effect of each dimension on relationship between extraversion and employeesâ innovation. Through the above analysis, it is concluded that extraversion has a positive effect on employeesâ innovative behavior; the five dimensions of organizational innovative climate all exert a positive effect on employeesâ innovative behavior; the resource support in organizational innovative climate has a moderating effect on the relationship between extraversion and employeesâ innovation. The research findings shed new light on the improvement of organizational innovative and the construction of an innovative country
Diversified pattern of the human colorectal cancer microbiome
BACKGROUND: The aim of this study is to expand existing knowledge about the CRC-associated microbiome among Han Chinese, and to further discover the variation pattern of the human CRC microbiome across all population. FINDINGS: Using pyrosequencing-based molecular monitoring of bacterial 16S rRNA gene from eight tumor/normal tissue pairs of eight Chinese CRC patients, we analyzed and characterized the basic features of the CRC-associated microbiome. Firstly, we discovered an increasing diversity among tumor-associated bacterial communities. Secondly, in 50% of Chinese CRC patients, we found a significant increase of Roseburia (P = 0.017), and a concurrent decrease of both Microbacterium (P = 0.009) and Anoxybacillus (P = 0.009) in tumor tissue. CONCLUSIONS: We discovered a novel CRC microbiome pattern in Chinese. Both the over-represented Roseburia bacteria at tumor sites and the over-represented Microbacterium and Anoxybacillus bacteria away from tumor sites were both closely related in Chinese CRC patients. Across several populations reported in this study and previously, we observed both common and distinctive patterns of human CRC microbiomeâs association with a high-risk of CRC
Effect of space flight factors on alfalfa seeds
To explore the effect of space flight factors on the early development of alfalfa seedling, dry seeds were placed onboard a satellite for a 15-day flight. After retrieval, the ultra structure of seed coat and the chemical content of seed were tested, followed by tests for germinate ability, seedling growth, and mitotic and chromosome aberrations. Results showed that space flight factors have both positive and negative effects on alfalfa seeds. Positive effects include: (1) A 6.2% increase in germinate potential and (2) an 80% decrease in the number of hard seed in flight seeds. Meanwhile, negative effects included a decrease of 3.0 and 33.2% in the index of germination and vigor of flight seeds, respectively, which may be partly due to the inhibition of cell mitotic (26% less than ground control) and root growth (29.0% less than ground control) after the space flight. Moreover, the DNA and Ca2+ content of alfalfa seeds increased after the space flight, while the reserve energy content of alfalfa seeds, such as saccharine and fatty acid, decreased after the space flight. Conclusively, space flight factors accelerate the germination process of alfalfa seeds but restrain the root from growing due to chromosomal damage and abnormal mitosis induced by cosmic radiation.Key words: Alfalfa, space flight factors, germination, chromosome aberration
Cavity-Enhanced Linear Dichroism in a van der Waals Antiferromagnet
Optical birefringence is a fundamental optical property of crystals widely
used for filtering and beam splitting of photons. Birefringent crystals
concurrently possess the property of linear dichroism (LD) that allows
asymmetric propagation or attenuation of light with two different
polarizations. This property of LD has been widely studied from small molecules
to polymers and crystals but has rarely been engineered per will. Here, we use
the newly discovered spin-charge coupling in van der Waals antiferromagnetic
(AFM) insulator FePS3 to induce large in-plane optical anisotropy and
consequently LD. We report that the LD in this AFM insulator is tunable both
spectrally and magnitude-wise as a function of cavity coupling. We demonstrate
near-unity LD in the visible-near infrared range in cavity-coupled FePS3
crystals and derive its dispersion as a function of cavity length and FePS3
thickness. Our results hold wide implications for use of cavity tuned LD as a
diagnostic probe for strongly correlated quantum materials as well as opens new
opportunities for miniaturized, on-chip beam-splitters and tunable filters.Comment: 14 pages, 5 figure
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