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  • Author: Haitao Li x
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Abstract

How to reduce the hardware cost and high power consumption of RF link of communication device is the key problem to be solved for multi-transmitting antenna and multi-receiving antenna system (MIMO). Always choose the best antennas connection a limited number of RF circuits, which is called antenna selection technology (AS), are a perfect solution to the problem, Assuming that the spatial range of the antenna meets the requirements of signal multiplexing and based on the maximum capacity criterion of the selected MIMO system, the manuscript proposes a low computational complexity (CC) and high performance joint transmitting and receiving antenna selection technique (JTRAS). Starting from the traditional capacity formula and the full matrix of MIMO channel, we utilize a simplified channel capacity expression through repeatedly iterating to delete a row and a column of the equivalent decrement channel matrix, which is to remove a pair of transmitting and receiving antennas. Based on the decreasing JTRAS (DJTRAS) algorithm, the capacity results of simulating calculation indicate that its median capacity overtakes other ones, such as optimum selection (OS), AS based on Frobenius 2 norm (NBS), and concise joint AS criterion (CJAS) etc., and the novel DJTRAS scheme can significantly reduce computational complexity (CC) compared to the exhaustive search method with maximum capacity, which defined as optimal algorithm in the curve graphs. This new technology of the AS is particularly suited to large number of selected antennas, such as Lt ≥ NT/2,Lr ≥ NR/2.

Quantified Analyses of Aggression Pattern in a Captive Population of Musk Deer (Moschus Sifanicus)

Alpine musk deer (Moschus sifanicus) are endangered as a result of habitat degradation and loss and centuries of widespread poaching. Consequently, musk deer farming was introduced as a measure to not only protect musk deer but also to provide a means for sustainable musk supply. An increased understanding of the social structure of captive populations is essential for both successful farming and improved welfare of individuals. This study recorded agonistic interactions between captive individuals at Xinglongshan Musk Deer Farm (XMDF), northwest China. The relationship between aggressive interactions and the individual's age and gender and opponent health was analysed. From our observations we found that stable social hierarchies developed within both captive male and gender-mixed musk deer groups. There was no significant correlation found between only age of individual and their status in the social hierarchy, and it was thus concluded, as social rank was not determined singularly by age, that a combination of other factors, such as experience and origin of the individual, better explain rank orders. Three forms of aggressive behaviour were expressed between males, in which threatening (56.38%±7.28%) was significantly more frequent than attacking (17.86%±5.94%) and displacing behaviours (25.78%±3.66%). There was no attacking behaviour observed in interactions initiated by males towards females, however displacing (70.85%±4.15%) was more common than threatening (29.15%±4.15%). Conflict-initiating male deer demonstrated more attacking and threatening behaviour towards male opponents than to female ones, however the differences were statistically insignificant. These results can be implemented into musk deer farming management practices through 1) rotating individuals within an enclosure on a frequent basis; 2) removing males from female enclosures after successful mating and 3) enclosing males in single sex enclosures. Furthermore, in order to improve musk deer farming and captive musk deer welfare, management systems should be kept relatively consistent in order to assist in establishing the stable social hierarchy patterns in captive populations.

Abstract

For the ultra-low frequency signals or adjacent Nyquist frequency signals, which exist in the vibration engineering domain, the traditional DTFT-based algorithm shows serious bias for phase difference measurement. It is indicated that the spectrum leakage and negative frequency contribution are the essential causes of the bias. In order to improve the phase difference measurement accuracy of the DTFT-based algorithm, two new sliding DTFT algorithms for phase difference measurement based on a new kind of windows are proposed, respectively. Firstly, the new kind of windows developed by convolving conventional rectangular windows is introduced, which obtains a stronger inhibition of spectrum leakage. Then, with negative frequency contribution considered, two new formulas for phase difference calculation under the new kind of windows are derived in detail. Finally, the idea of sliding recursive is proposed to decrease the computational load. The proposed algorithms are easy to be realized and have a higher accuracy than the traditional DTFT-based algorithm. Simulations and engineering applications verified the feasibility and effectiveness of the proposed algorithms.

Abstract

Signal processing precision of Coriolis mass flowmeters affects the measurement accuracy directly. To improve the measurement accuracy of Coriolis mass flowmeters, a phase and frequency matching-based signal processing method for Coriolis mass flowmeters is proposed. Estimated phase difference is obtained by means of frequency estimation, 90° phase shift, generating reference signals and cross-correlation. Simulated results demonstrate that the proposed method has better phase difference estimation and anti-interference performance than the Hilbert transform method, cross-correlation method, data extension-based correlation method, and quadrature delay estimator. Measurement results of Coriolis mass flowmeters verify the effectiveness and superiority of the proposed method in practice.

Abstract

Objective To observe the application of continuous renal replacement therapy (CRRT) and heparin anticoagulation in patients with HFRS, and to explore a more suitable anticoagulant strategy.

Methods Eighty-five severe-type patients (severe group) and 71 critical-type patients (critical group) were enrolled in this study. The frequency of CRRT was compared between the two groups; the frequency of CRRT treated with and without heparin anticoagulation and the frequency of hemorrhage and channel blood clotting induced by the two anticoagulant strategies were observed.

Results The frequency of CRRT in the critical group was higher than that in the severe group (P < 0.001). The frequency of CRRT initiated during the overlapping phases in the critical group was significantly higher than that of the severe group (P = 0.032). The total times of CRRT was 103, and 70 of them were treated with heparin anticoagulation. The frequencies of hemorrhage induced by heparin anticoagulation and no heparinization were 16 and 0, respectively, and the frequencies of channel blood clotting were 2 and 4, respectively.

Conclusions CRRT has been used extensively in the critical-type patients with HFRS. The heparin anticoagulation and no anticoagulant strategies should be used more rationally in patients treated with CRRT, according to the clinical characteristics of the disease.

Impact of Transitory Hyperprolactinemia on Clinical Outcome of In Vitro Fertilization and Embryo Transfer

This study aimed to evaluate the impact of serum prolactin concentration at the day of human chorionic gonadotropin (HCG) administration on the clinical outcome of in vitro fertilization and embryo transfer (IVF-ET). A total of 184 patients receiving the IVF-ET/ICSI-ET from October 2005 to March 2008 were retrospectively analyzed. Subjects were divided into four groups according to the serum prolactin concentration [<30 ng/mL (A), 30-60 ng/mL (B), 60-90 ng/mL (C), ≥90 ng/mL (D)] on the day of HCG administration during controlled ovarian stimulation (COS). In the Groups A, B, C and D, the implantation rate was 11.76%, 19.71%, 12.72% and 2.22%, respectively, and the pregnancy rate (PR) was 25.00%, 42.70%, 27.30% and 5.88%, respectively. The implantation rate and PR in the Group D were markedly lower than those in the remaining groups (P=0.011 and 0.009). During the COS, the serum prolactin concentration was dramatically elevated when compared with the baseline level leading to transient hyperprolactinemia. In addition, the implantation rate and pregnancy rate were significantly markedly decreased when the serum prolactin concentration was remarkably increased (≥90 ng/mL). To improve the clinical pregnancy rate of IVF-ET, close monitoring and appropriate intervention are needed for patients with an abnormal prolactin level during the COS.

Abstract

This article reports two asymptomatic cases of SARS-CoV-2 infection. Both cases came from Hubei Province. One was a 63-year-old male and the other was a 29-year-old female. Both were diagnosed with SARS-CoV-2 infection during the screening of high-risk personnel from the affected areas. During the 14-day isolation medical observation, they had no symptoms, their blood lymphocyte count and lung CT examinations were normal. An asymptomatic infection had been diagnosed, however, it was not “asymptomatic infection” state in incubation period. Due to the timely and effective isolation measures taken for the two cases, no other persons have been infected by them. Therefore, effective control of the source of infection, cutting off the route of transmission, and protecting vulnerable populations are currently effective measures to prevent the spread of coronavirus infected disease.