ENVIRONMENT

For many farmers in the United States, temperature rise and precipitation will not happen at the worst. Strengthening drought conditions affects corn and soybean crops throughout the Midwest, increasing concerns about food prices and future food prices. According to the US drought monitoring report, 88% of this year's maize crops and 77% of soybean crops are affected by the worst drought since 1988. The US Department of Agriculture (USDA) provides drought aid to 1,584 counties in 32 states. Warning of food price rise in 2013 due to reduced production of corn and soybean

The price of corn is now $ 9 per bushel, rising 50% from June. In addition, the price of soybeans recorded a record high of $ 17 per bushel, due to a decline in crop yield associated with drought. Rising prices may benefit farmers in the short term, but consumers will experience the impact of price increases in the form of more money on poultry, beef, pork and dairy products.

Almost half of domestic corn production is used as livestock feed, and now large-scale livestock producers are encouraging importing corn from Brazil. Most directly, poultry prices are expected to rise 5% to 5% due to faster animal growth and higher feed prices. The price of beef is expected to rise by 5% from 4% in November, but the growth rate is slow. This reflects longer term birth and growing demand for beef cattle.

In other words, each execution context has a lexical environment. This vocabulary environment contains variables and their associated values ​​and also includes references to those external environments. The vocabulary environment is either the global environment, the module environment (including the binding of the module's top declaration), or the function environment (the environment created by calling the function). Based on the above definition, we can see that the environment has access to its parent environment and that its parent environment can access its parent environment. This set of identifiers that each environment can access is called a "scope". Scopes can be nested in a hierarchical environmental chain called "scope chain".

Each function has an environment that gives the meaning of the variable in the function and an execution context that contains a reference to its parent environment. With reference to the parent environment, all internal variables in the parent scope are made available to all internal functions, whether internal functions are called outside the internal function or within the scope of creating them. Calling function test returns 45. This is the return value of the calling function bar (since foo returns bar). Even after the function foo returns, bar can access the free variable y. This is because bar refers to y through its external environment, this is the environment of foo. Since foo's environment can access the global environment, Bar can also access the global variable x. This is called "range chain lookup".