The poultry red mite (PRM), Dermanyssus gallinae, is one of the most detrimental ectoparasite on poultry farms worldwide. The blood fed on birds provides the mites with nutrition and energy for their activities, development and reproduction. In the evaluation of the efficacy of novel drugs or vaccines against PRMs, their effects on blood digestion are generally used as a key parameter. The blood digestion of haematophagous arthropods (including D. gallinae) is usually assessed by weighing; however, this method shows some limitations. The main objective of the present study was to develop a scoring method that can quickly and visually evaluate the blood digestion status of PRMs. A 0–4 point scoring criterion was established to describe the blood digestion status of D. gallinae based on the changes in appearance in the intestinal tract of PRMs during the blood digestion process. There was a good consistency between the results obtained by the blood digestion scoring and the weighing, indicating the reliability of this new method. The results obtained from volunteers were consistent with the results from researchers with low coefficient of variation, indicating that the scoring method has good practicability. The applicability of the scoring method was confirmed in an efficacy study, where it was found that doramectin could significantly inhibit the blood digestion of PRMs, lowering the blood digestion score.
Inlet pipes of the centrifugal pump are generally bent to fit in the limited installation space, which can cause inflow distortions for two sides of the double-suction impeller. This study aimed to understand the effect of primary geometric parameters of inlet pipes, including corner angle, straight pipe length downstream of elbow, and turning radius, on pump performance and pressure fluctuations. The pump head, efficiency, and pressure fluctuations were measured for six kinds of inlet pipes in the experiment. Unsteady numerical simulations were performed to understand the flow mechanisms. Results indicate that the bending of inlet pipes is a significant reason for the loss of pump head and efficiency. The penalty on pump performance is augmented by the increase in corner angle, decrease in turning radius, and installation of a short straight pipe downstream of the elbow. Pump efficiency could be maximally reduced by 6.58% with a large corner angle and a small turning radius. The bending of inlet pipes induces pressure imbalance for the two sides of the impeller and increases low-frequency disturbance in the suction chamber, which are responsible for the performance loss. Numerical results reveal that the low-frequency disturbance is caused by the vortex formed in the suction chamber, and the accompanying secondary vortex aggravates the pressure fluctuation synchronously. Parametric studies conclude that the corner angle should be minimized to reduce the penalty on pump performance and pressure fluctuations, and a long straight pipe downstream of the elbow can be installed to decrease vibration for the pump with bent inlet pipes.
To alleviate the data collection latency problem in mobile WSNs, we shorten the data collection path by visiting a minimal set of points in the network, which we call the Stop Point Set (SPS). A point selection method named pathpoints identification method has been proposed recently, which plays the same role as our SPS calculating method. However, as a clustering based method, it may not scale well when the WSN is large. Furthermore, there exists some uncertainty in its clustering implementation. In this paper, we compare the path-points identification method with our stop point selection method, and verifies our prediction about its scalability and uncertainty. We also proposed one feasible modification to improve its performance. Our work is evaluated by comprehensive simulations. The results show that our stop point selection method outperforms the path-points identification method both in terms of the size of resulting SPS and the length of data collection path.
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