Effects of Periodical Salinity Fluctuation on the Growth, Molting, Energy Homeostasis and Molting-Related Gene Expression of Litopenaeus vannamei

To determine the response of Litopenaeus vannamei to periodical salinity fluctuation, a 30-day experiment was conducted in laboratory. In this experiment, two salinity fluctuation amplitudes of 4(group S4) and 10(group S10) were designed. The constant salinity of 30(group S0) was used as the control. Levels of shrimp growth, molting frequency(MF), cellular energy status(ATP, ADP and AMP), as well as the expression of genes encoding molt-inhibiting hormone(MIH), crustacean hyperglycemic hormone(CHH), ecdysteroid-regulated protein(ERP), and energy-related AMP-activated protein kinase(AMPK) were determined. The results showed that periodical salinity fluctuation significantly influenced all indicators except MF which ranged from 13.3% in group S10 to15.4% in group S4. In comparison with shrimps cultured at the constant salinity of 30, those in group S4 showed a significant elevation in growth rate, food conversion efficiency, cellular energy status, ERP and MIH gene transcript abundance, and a significant reduction in CHH and AMPK transcript abundance(P < 0.05). However, salinity fluctuation of 10 only resulted in a significant variation in MIH and CHH gene expression when compared to the control(P < 0.05). According to our findings, L. vannamei may be highly capable of tolerating salinity fluctuation. When ambient salinity fluctuated at approx. 4, the increased MF and energy stores in organisms may aid to promoting shrimp growth.

Fluidization stability and periodic fluctuations in gas–solid separation fluidized bed using Geldart A dense medium

Gas–solid separation fluidized bed is a typical method for coal separation without water utilization.Geldart A particles is also considered as the ideal dense medium to strengthen separation efficiency.Fluidization stability reflects the bed pressure fluctuations and the distribution of bubble and emulsion phases,affecting the separation performance.And the main frequency of pressure fluctuations can directly reflect the degree of pressure fluctuations.Therefore,the detailed fluidization stability is analyzed combined the method of standard deviation of pressure fluctuations,power spectral density,etc.,for Geldart A particles.The results showed that maintaining an appropriate gas velocity resulted in an average bed pressure of around 2000 Pa.The main frequency is mainly concentrated around 1–1.5 Hz.Finally,a prediction model of the main frequency of pressure fluctuations is established,and the error can be controlled within±0.15.The investigation further proved the stable fluidization of Geldart A particles and provides a method for predicting the main frequency of pressure fluctuations in the gas–solid separation fluidized bed.

Don＇t Overlook GDP and Investment： An Analysis of China＇s Current Economic Trend

In this paper, we first examine various causes of China＇s unexpected low economic growth rate since the beginning of 2012. Particularly, we propose the possibility of one tendency masking the other tendency. That is, there is a tendency of neglecting and downplaying GDP while making fewer efforts to develop economy in some regions that oppose GDP worship and irrational pursuit of and competition for GDP,, which deserves our full attention. We further propose in this paper that the decline of China＇s potential economic growth rate should keep a gradual process and the government should favor consumption while not overlooking investment, given that a certain amount of moderate investment will remain the key impetus to China＇s economic growth over a certain period in the future.

Discussion on the paper “Analyzing short time series data from periodically fluctuating rodent populations by threshold models: A nearestblock bootstrap approach”

The authors are to be congratulated for an innovative paper in terms of both modelling methodology and subject matter significance. The analysis of short time series is known to be

Discussion on the paper “Analyzing short time series data from periodically fluctuating rodent populations by threshold models: A nearestblock bootstrap approach”

This is a very attractive article. It combines fascinating new methodology with a most interesting dataset, and a highly motivating presentation. However, despite the many

Continuous Commutation Failure Suppression Method Based on Self-adaptive Auto-disturbance Rejection Proportional-integral Controller for HVDC Transmission System

Once an asymmetrical fault occurs on the AC side of the receiving-end of a high-voltage direct current(HVDC)transmission system,the current reference will be affected by the control regulation on the DC inverter side and the commutation voltage asymmetry.In this case,the advance firing angle will fluctuate periodically,causing security threats to the system.If the fault cannot be cleared in time,the effect may be even more serious.However,the traditional proportional-integral(PI)controller cannot effectively suppress the periodic components in the input error signal,which is an important cause of continuous commutation failure.Thus,the system requires more time to recover from the fault.Motivated by this,a selfadaptive auto-disturbance rejection PI controller is proposed in this study.The controller has the advantages of fast response speed and strong anti-interference ability of the auto-disturbance rejection controller.On one hand,it can automatically adjust PI,and the parameters can maintain the system’s adaptive ability.On the other hand,the discretization process satisfies the computer simulation requirements.By applying the proposed controller to a system under constant current control and extinction angle control,the dynamic response speed can be improved and the robust performance of the system can be ensured when dealing with a wide range of perturbations.Finally,simulation results show that the proposed algorithm can effectively suppress the continuous commutation failure of DC transmission systems.

instanton quantum tunneling Jacobi elliptic functions Lamé functions

Under condition of four potential fields, equations of motion and fluctuations in imaginary time are utilized to analytically derive the basic and fluctuating periodic instantons. It is shown that the basic instantons satisfy the elliptic or simple pendulum equations and their solutions are Jacobi elliptic functions, and fluctuating periodic instantons satisfy the Lam′e equation and their solutions are Lame functions. These results indicate that there exists the common solution family for different potential fields which are called the super-symmetry family.