With increasing fishing pressures having brought several stocks to the brink of collapse, there is a need for developing efficient harvesting methods that account for factors beyond merely yield or profit. We consider the dynamics and management of a stage-structured fish stock. Our work is based on a consumer-resource model which De Roos et al. (in Theor. Popul. Biol. 73, 47-62, 2008) have der...

In this paper we study bifurcations in predator-prey systems with seasonal prey harvesting. First, when the seasonal harvesting reduces to constant yield, it is shown that various kinds of bifurcations, including saddle-node bifurcation, degenerate Hopf bifurcation, and Bogdanov– Takens bifurcation (i.e., cusp bifurcation of codimension 2), occur in the model as parameters vary. The existence o...

In this article, we study a ratiodependent predator-prey system where predator population is subjected to harvesting with MichaelisMenten type harvesting rate. We study the existence of heteroclinic bifurcations in an exploited predatorprey system by using Melnikov’s method. Our simulation results also show that the system may exhibit monostability, bistability and tristability depending on the...

Technical aspects of composite arterial grafting with double skeleton-ized internal thoracic arteries. Bilateral skeleton-ised internal thoracic artery graftings in off-pump coronary artery bypass: early result of Y versus in situ grafts. results of coronary grafting using ultrasonically skeletonized internal thoracic arteries. We read with great interest the recent review from Dr. Ali and cowo...

A comparison of 14 currently applicable wood harvesting systems was assessed with respect to ergonomic point of view. For this purpose, the research method, based on the Hodges-Lehmann rule and the integrated work-severity rate of single machinery, was developed for ergonomic evaluation of cut-to-length, tree-length and full-tree harvesting systems. Altogether, about 130 different parameters of...

Energy harvesting, which offers a never-ending energy supply, has emerged as a prominent technology to prolong the lifetime and reduce costs for the battery-powered wireless sensor networks. However, how to improve the energy efficiency while guaranteeing the quality of service (QoS) for energy harvesting based wireless sensor networks is still an open problem. In this paper, we develop statist...

BACKGROUND The saphenous vein is an important conduit for coronary artery bypass grafting. Wound complications from traditional open vein harvesting occur often. Minimally invasive endoscopic saphenous vein harvesting may decrease wound complications. Vein quality may be an issue with endoscopic harvesting. METHODS We reviewed 568 patients who had bypass grafting and saphenous vein harvesting...

We analyse the effect of harvesting in a resource dependent age structured population model, deriving the conditions for the existence of a stable steady state as a function of fertility coefficients, harvesting mortality and carrying capacity of the resources. Under the effect of proportional harvest, we give a sufficient condition for a population to extinguish, and we show that the magnitude...

Energy is everywhere in the environment surrounding us i.e. it is available in the form of thermal energy, light (solar) energy, wind energy, and mechanical energy etc. However, the energy from these sources is often found in such minute quantities that it cannot supply adequate power for any viable purpose. In fact, it has not been possible to capture such energy sufficiently to perform any us...

forest cover is one of the most effective factors in reducing flooding in northern iran, so that in recent years the destruction, land use changing and uncontrolled harvesting of forest areas, has greatly increased the number and magnitude of floods. so far, there have been few studies on forest hydrology in iran, particularly the northern hyrcanian forests. this study examines the impact of a ...