where X ( t ) represents the equity curve of the trading system or fund. The maximum drawdown MDD is the most widespread risk measure among money managers and hedge funds. It is often preferred over some of the other risk measures because of the tight relationship between large drawdowns and fund redemptions. Also, a large drawdown can even indicate the start of a deterioration of an otherwise ...

Between 5 and 6 million years ago, during the so-called Messinian salinity crisis, the Mediterranean basin became a giant salt repository. The possibility of abrupt and kilometre-scale sea-level changes during this extreme event is debated. Messinian evaporites could signify either deep- or shallow-marine deposits, and ubiquitous erosional surfaces could indicate either subaerial or submarine f...

[1] Seasonal cycles of atmospheric CO2 and d O-CO2 at high northern latitudes have the potential to serve as indicators of ecological change in response to climate changes. Effective interpretation of these observations requires an understanding of how different species and ecosystems contribute to biosphere-atmosphere exchange. Here we examined the effect of postfire stand age in boreal forest...

To protect the security of energy supplies, China is building a national strategic petroleum reserve (SPR). Here we present a dynamic programming model to determine the optimal drawdown strategies for SPR under various scenarios, focusing on minimizing cost. In a natural disaster scenario, the optimal strategy is rapid drawdown of ~10% of the reserve to stabilize oil prices and ease supply shor...

The impact of ground water pumping on nearby streams is often estimated using analytic models of the interconnected stream-aquifer system. A common assumption of these models is that the pumped aquifer is underlain by an impermeable formation. A new semianalytic solution for drawdown and stream depletion has been developed that does not require this assumption. This solution shows that pumping-...

The Latrobe Valley has an extensive monitoring network to measure the environmental impacts of mining and power generation operations. Regional groundwater and topographic survey data have been recorded for over 40 years. This data is used to calibrate mathematical models for the prediction of groundwater drawdown and subsidence. The concept of artificially recharging aquifers through re-inject...

An iron enrichment experiment (Subarctic Ecosystem Response to Iron Enrichment Study), SERIES was carried out at Ocean Station Papa (50°N, 145°W) in the subarctic Northeast Pacific Ocean in July 2002, in order to observe the physiological, ecological and biogeochemical responses to a release from iron stress in these high-nitrate, low-chlorophyll (HNLC) waters. The patch was created by injectin...

Alterations to water management practices, in response a growing demand maximize energy production from renewable sources, threaten exacerbate anticipated future shortages caused by severe drought episodes, brought on climate change. Across Scotland, many highly managed systems are inhabited some of the last remaining reproductively viable populations freshwater pearl mussel, Margaritifera marg...

The Colorado River Basin is experiencing a significant drought that began in 2000. As water supplies are projected to continue declining, managers concerned with the ongoing treatability of Lake Mead water, which provides 90% source for Las Vegas Valley, and crucial link downstream water. drinking intake currently draws high-quality, low-turbidity water; however, turbidity increase. This study ...

Abstract Water resources management in high-stress regions is a large-scale problem affecting food and water security. Therefore, modern irrigation systems such as sprinklers, subsurface, drip irrigations are applied to manage the shortage of Nile delta. Because increase population rate climate change, freshwater supplies significantly limited must be efficiently managed. Consequently, Egypt pl...