THE HYDRAULICS OF NATURE-LIKE FISHWAYS

Nature-like fishway arrangements are commonly used because these structures imitate the characteristics of natural rivers and effectively allow fish to migrate past river sections blocked by hydraulic structures. In this paper, physical models were analyzed, and the velocity distributions of two different fishway structures (Types I and II) were compared. Results showed that the maximum mainstream velocity of the Type I structure was 5.3% lower than that of the Type II structure. However, the average mainstream velocity of the Type I structure was 21.1% greater than that of the Type II structure. The total per-cycle length of the mainstream path in the Type II structure was 2.1 times greater than that of the Type I structure, which indicated that the length of the mainstream path was somewhat proportional to the average velocity of the mainstream. When the flow rate was kept constant, increases in the velocity of the main flow associated with changes in the internal structure of the fishway decreased the average velocity of the main flow, while decreases in the total length of the flow path led to increases in the average velocity of the main flow. Due to frictional head loss along the fishway and local head loss, as well as the overlaps between these factors, the overall flow rate gradually decreased every cycle, despite periodic fluctuations

Housing Crises in Pakistan: Review of Population Growth and Deficiencies in Housing Laws and Policies

The advanced technologies in agricultural sector and rapid industrialization cause massive rural-urban migration in Pakistan. In 2011, the level of urbanization was 36.2, while there were 21.7 million houses in the country as against the population of 186 million. Pakistan is facing shortage of 9 million residential houses, which is growing with the ratio of 600,000 annually. Pakistan is still in its infancy when compared with other developing and developed countries. Although the country has plethora of laws and policies to strengthen the housing sector, yet there are still many legal loopholes and gapes in effective implementation. The present research will explore housing demand and supply gaps, laws and policies and status of their implementation in the country. The research also finds the weaknesses of laws and policies implementation for the improvement of housing sector in Pakistan and Present some remedial strategies to strengthen the housing secto

Evaluating the TRMM Multisatellite Precipitation Analysis for Extreme Precipitation and Streamflow in Ganjiang River Basin, China

Based on the observed precipitation data and TRMM (Tropical Rainfall Measuring Mission) 3B42 RTV7 and 3B42 V7 precipitation products from 2003 to 2010, the extreme precipitation and streamflow in the Ganjiang River basin were analyzed. The VIC hydrological model was used to simulate the streamflow driven by RTV7/V7 precipitation products in the Ganjiang River basin. The results show that (1) both of the RTV7 and V7 precipitation products have good applicability in precipitation estimation in the Ganjiang River basin and the correlation between the observed precipitation and RTV7 (V7) was as higher as 0.85 (0.86); (2) the RTV7/V7 precipitation products can well be used to simulate the streamflow by using the VIC hydrological model and the correlation between the observed streamflow and simulated streamflow driven by RTV7 (V7) products was as high as 0.86 (0.89); (3) the extreme precipitation varied greatly in the Ganjiang River basin and both of the RTV7 and V7 can capture the pattern of extreme precipitation in the Ganjiang River basin; however, higher extreme precipitation can be found in the northern Ganjiang River basin; (4) the extreme streamflow simulated driven by RTV7/V7 products agreed well with the observed extreme streamflow in the Ganjiang River basin. This study indicated that the TRMM 3B42 RTV7 and V7 products can be well used in the estimation of extreme precipitation and extreme streamflow

Evolutionary prisoner's dilemma game with dynamic preferential selection

We study a modified prisoner's dilemma game taking place on two-dimensional disordered square lattices. The players are pure strategists and can either cooperate or defect with their immediate neighbors. In the generations each player update its strategy by following one of the neighboring strategies with a probability dependent on the payoff difference. The neighbor selection obeys a dynamic preferential rule, i.e., the more frequently a neighbor's strategy was adopted by the focal player in the previous rounds, the larger probability it will be chosen to refer to in the subsequent rounds. It is found that cooperation is substantially promoted due to this simple selection mechanism. Corresponding analysis is provided by the investigations of the distribution of players' impact weights, persistence, and as well as correlation function.Comment: 7 pages, 5 figure