quarta-feira, 8 de dezembro de 2010

GM crops

Genetically modified (GM) foods are foods derived from genetically modified organisms.

GM foods were first put on the market in the early 1990s. Typically, genetically modified foods are transgenic plant products: soybean, corn, canola, and cotton seed oil. Animal products have also been developed, although as of July 2010 none are currently on the market. In 2006 a pig was controversially engineered to produce omega-3 fatty acids through the expression of a roundworm gene. Researchers have also developed a genetically-modified breed of pigs that are able to absorb plant phosphorus more efficiently, and as a consequence the phosphorus content of their manure is reduced by as much as 60%.
Critics have objected to GM foods on several grounds, including possible safety issues, ecological concerns, and economic concerns raised by the fact that these organisms are subject to intellectual property law.

Miguel Sousa nº 25 11ºB

http://en.wikipedia.org/wiki/Genetically_modified_food

Noise pollution



Noise pollution is a type of energy pollution in which distracting, irritating, or damaging sounds are freely audible. As with other forms of energy pollution (such as heat and light pollution), noise pollution contaminants are not physical particles, but rather waves that interfere with naturally-occurring waves of a similar type in the same environment.
In the narrowest sense, sounds are considered noise pollution if they adversely affect wildlife, human activity, or are capable of damaging physical structures on a regular, repeating basis. In the broadest sense of the term, a sound may be considered noise pollution if it disturbs any natural process or causes human harm, even if the sound does not occur on a regular basis.
The causes of noise pollution in general are obvious - construction sites, highway vehicle traffic, industrial companies, air traffic, rail traffic, fire workers and others. While many of these sources are unavoidable in daily life, the exposure to them can be kept to a minimum with a little personal effort.

The unwanted sound is called noise. This unwanted sound can damage physiological and psychological health. Noise pollution can cause annoyance and aggression, hypertension, high stress levels, tinnitus, hearing loss, sleep disturbances, and other harmful effects. Furthermore, stress and hypertension are the leading causes to health problems, whereas tinnitus can lead to forgetfulness, severe depression and at times panic attacks.
This type of pollution has become more significant due to technological and industrial developments. We have a duty to stop as fast as possible with this problem because, in the future, would have consequences even more disastrous.


  • Miguel Sousa nº25 11ºB

Opinion

We think that although genetically-modified foods have the potential to solve many of the world's hunger and malnutrition problems and being an important think at the economis point of view they have to many incovenients and dangers.
We can't be sure that they will not be harmful to our health and to the health of the future generations, as also to the species in which are done these genetic modifications and the problem is that, we will only know that at the generation of our grandsons and by that time, probably will be too late...bet we hope he wrong about his!
  • Ana Costa, Joana Gomes and Miguel Sousa
  • 11ºB