Acid rain and… the facts
www.acidrain.org.ca / Oxford Children´s Encyclopedia
What causes acid rain?
Acid rain is caused by air pollution. When fossil fuels such as coal and oil are burned, two gases, sulphur dioxide and nitrogen oxide, are released into the atmosphere. These two pollutants eventually react with the moisture in the air. When this polluted mixture falls onto the ground, it is called acid rain.
Rain measuring between 0 and 5 on the pH scale, is acidic therefore called ACID RAIN
Acid rain is harmful to the environment. It is hard to control because it may be blown by the wind, falling thousands of kilometers from where it was first formed. For example, much of the acid rain in Canada is caused by smoke from factories and power‐stations in the USA. The acid rain in Scandinavia may come from Britain.
What are the effects of acid rain?
Acid rain has many different effects. It has killed fish in the lakes of North America, Scandinavia, Scotland, and Wales. Vast areas of forest in northern and central Europe are dying because of it, while in many European cities statues and stone buildings are being eaten away by the acid. Acid rain corrodes metalwork such as steel bridges and railings; it also attacks some types of concrete. Even the water that we drink is slowly being polluted by acid rain.
What are the effects on trees and soil?
One of the most serious impacts of acid precipitation is on forests and soils. Great damage is done when sulphuric acid falls onto the earth as rain. Nutrients present in the soils are washed away. Aluminium also present in the soils is freed and this toxic element can be absorbed by the roots of trees. Thus, the trees starve to death because they have been deprived of their vital nutrients such as calcium and magnesium.
Acid rain is one of the most serious environmental problems of our time. It is a global problems that is gradually affecting our world.
How does acid rain effect lakes?
Lakes that have been acidified cannot support the same variety of life as healthy lakes. As a lake becomes more acidic, various types of fish disappear. Other effects of acidified lakes on fish include: decreased growth, inability to regulate their own body chemistry, reduced egg deposition, deformities in young fish and increased susceptibility to naturally occurring diseases.
Clean rain usually has a pH of 5.6. It is slightly acidic because of carbon dioxide which is naturally present in the atmosphere. Vinegar, by comparison, is very acidic and has a pH of 3.
What is pH?
This is a measure of how acidic or alkaline a substance is. (See a pH scale below). The initials pH stand for Potential of Hydrogen. Acids have pH values under 7, and alkalis have pH values over 7. If a substance has a pH value of 7. It is neutral‐neither acidic or alkaline.
Because the pH scale is logarithmic, a difference of one pH unit represents a tenfold, or ten times change. For example, the acidity of a sample with a pH of 5 is ten times greater than that of a sample with a pH of 6. A difference of 2 units, from 6 to 4, would mean that the acidity in one hundred times greater, and so on.
Acid rain does NOT cause
Acid rain and… the facts
www.acidrain.org.ca / Oxford Children´s Encyclopedia
What causes acid rain?
Acid rain is caused by air pollution. When fossil fuels such as coal and oil are burned, two gases, sulphur dioxide and nitrogen oxide, are released into the atmosphere. These two pollutants eventually react with the moisture in the air. When this polluted mixture falls onto the ground, it is called acid rain.
Rain measuring between 0 and 5 on the pH scale, is acidic therefore called ACID RAIN
Acid rain is harmful to the environment. It is hard to control because it may be blown by the wind, falling thousands of kilometers from where it was first formed. For example, much of the acid rain in Canada is caused by smoke from factories and power‐stations in the USA. The acid rain in Scandinavia may come from Britain.
What are the effects of acid rain?
Acid rain has many different effects. It has killed fish in the lakes of North America, Scandinavia, Scotland, and Wales. Vast areas of forest in northern and central Europe are dying because of it, while in many European cities statues and stone buildings are being eaten away by the acid. Acid rain corrodes metalwork such as steel bridges and railings; it also attacks some types of concrete. Even the water that we drink is slowly being polluted by acid rain.
What are the effects on trees and soil?
One of the most serious impacts of acid precipitation is on forests and soils. Great damage is done when sulphuric acid falls onto the earth as rain. Nutrients present in the soils are washed away. Aluminium also present in the soils is freed and this toxic element can be absorbed by the roots of trees. Thus, the trees starve to death because they have been deprived of their vital nutrients such as calcium and magnesium.
Acid rain is one of the most serious environmental problems of our time. It is a global problems that is gradually affecting our world.
How does acid rain effect lakes?
Lakes that have been acidified cannot support the same variety of life as healthy lakes. As a lake becomes more acidic, various types of fish disappear. Other effects of acidified lakes on fish include: decreased growth, inability to regulate their own body chemistry, reduced egg deposition, deformities in young fish and increased susceptibility to naturally occurring diseases.
Clean rain usually has a pH of 5.6. It is slightly acidic because of carbon dioxide which is naturally present in the atmosphere. Vinegar, by comparison, is very acidic and has a pH of 3.
What is pH?
This is a measure of how acidic or alkaline a substance is. (See a pH scale below). The initials pH stand for Potential of Hydrogen. Acids have pH values under 7, and alkalis have pH values over 7. If a substance has a pH value of 7. It is neutral‐neither acidic or alkaline.
Because the pH scale is logarithmic, a difference of one pH unit represents a tenfold, or ten times change. For example, the acidity of a sample with a pH of 5 is ten times greater than that of a sample with a pH of 6. A difference of 2 units, from 6 to 4, would mean that the acidity in one hundred times greater, and so on.
It is true that clean rain
1. The ECOWAS COMMISSION has allocated own funds towards the cost of the Supply, Deployment & Installation of Network Equipment at the ECOWAS Commission Headquarters Data Centre, Abuja.
2. The ECOWAS Commission therefore invites sealed bids for the Supply, Deployment & Installation of Network Equipment at the ECOWAS Commission Headquarters Data Centre, Abuja described above in one lot.
3. The Bidding Document can be obtained at the Procurement Division, Directorate of General Administration, ECOWAS Commission, Plot 101, Yakubu Gowon Crescent, Asokoro District, Abuja, Nigeria, upon submission of a written request and payment of three hundred US Dollars (US$300.00) by Cash or Bank Draft made in favour of ECOWAS Commission, Abuja.
4. For Bidders outside Nigeria, the Bidding Document can be mailed to interested Bidders upon payment (by Transfer) of non‐refundable fee of US$300.00 to the Commission (transfer charges born by the bidder). (Account Details available on request.)
5. Interested Bidders may obtain further information at the address below, during office hours: Monday to Friday from 9.00am (8.00am GMT+1) to 4.00pm (3.00pm GMT+1), ECOWAS Commission, Directorate of General Administration, Procurement Division, 1st Floor, Plot 101, Yakubu Gowon Crescent, Asokoro District, PMB 401 Abuja Nigeria.
E‐mail: [email protected]
6. Bids shall be valid for a period of 120 (days) after Bid Opening and must be accompanied by a bid security of US$20,000.00 (Bank Guarantee or Insurance Bond).
7. Bids shall be delivered in sealed envelope and deposited in the ECOWAS Tender Box located Office of the Executive Assistant of Commissioner of Administration & Finance, fifth (5th) floor of the ECOWAS Commission Building, 101, Yakubu Gowon Crescent Asokoro District, P. M. B. 401, Abuja, Nigeria on or before November 7, 2013 at 11.30am (10.30am GMT+1) and clearly marked “International Competitive Bidding for the Production of ECOWAS Biometric Laissez Passer and Supply of Equipment” Do Not Open, Except in Presence of the Committee.
8. Bids will be opened in the presence of the bidders who wish to attend on November 7, 2013 at 12.00 noon (11.00am GMT+1), Room 523, Ecowas Commission, Abuja, Nigeria.
(The Economist, September 4th, 2013. Page 86. Adaptado.)
The ECOWAS Commission is inviting bids for a(an)
The sentence “incidental bycatch” means that this kind of catch WASN`T:
Procedural programming has been around since the
inception of computers and programming. Object–oriented
paradigms arrived a little later — in the late 1950s to early 1960s
— which means over 50 years of object–oriented problem solving.
Still, many developers lack a full understanding of the thought
process in developing object–oriented software and therefore can't
take advantage of its concepts. I'm happy to see that this book, The
Object–Oriented Thought Process, has taken this fairly old
perspective and given it full attention and renewed interest.
Not having read the previous editions, I'm not familiar
with the changes represented in this fourth edition. Author Matt
Weisfeld is a professor who understands these important concepts
and the level of knowledge and process required for readers and
students to grasp what they need to know. The examples in the book
are concise, clear, and easy to follow. Additionally, the book makes
good use of white space, lists, pictures, and diagrams to make the
content easier to follow and scan quickly.
Weisfeld has organized the concepts to build on each
other, ensuring that students understand one concept well before
moving to the next. On the other hand, readers who already
understand the fundamentals can go directly to object–oriented
thought processes for particular programming paradigms, such as
Web services or client–server applications.
The book is language–neutral. Its examples are in C#, but
a supplementary website offers example code in other languages. If
your language isn't fairly represented, don't be deterred from
acquiring this book because object–oriented concepts and semantics
are mostly universal — just the particular implementation might
vary due to the language.
Each chapter contains UML and example code to better
understand the concepts and see how they're implemented. The last
chapter introduces design patterns but without going into great
detail about how to use them. This lets the inexperienced reader
know that design patterns would be the next step in the path to
developing good code.
Overall, I can recommend this book to code developers,
designers, and testers — to anyone with an interest in proper
software development semantics. It's available in a digital format
that serves as a useful ready reference.
Scott Brookhart. Thinking about objects.
Internet:
Considering the book review above, judge the following items.
It can be infered from the text that the author of the book is a
famous computer programmer.
In the fragments of the text: “they may lose the desire to master whatever task you are asking them to do” (lines 12-13) and “then you have to do more than just present lessons in the app” (lines 18-19), the verb forms in bold express the ideas, respectively, of
One of the roles the WTO plays is that of an arbitrator that will hear the cases of countries arguing about trade.
If industrial property laws did not exist, it is likely that there would be less interest in and money for research and development of new technology.
“... provide opportunities for learners to participate in open-ended meaningful interaction
through language learning tasks, assuming that a preoccupation with meaning making will
ultimately lead to L2 mastery”.
(Kumaravadivelu 1994, p. 29).
To achieve such goal a teacher should introduce
“The linguists and applied linguists who had such a profound influence on the development
of several varieties of communicative language teaching (CLT) were dissatisfied with
pedagogical approaches which treated language a set of morpho-syntactic rules rather
than as a richer system of communication involving many kinds of competence other than
purely syntactic”
(Lightbown 2000, p. 435)
As developers of CLT, these linguists and applied linguists wanted to
16
Ten are the principles that teachers should follow in instructed second language
acquisition (Ellis 2008). One of such principles stated that “instruction needs to ensure that
learners focus predominantly on meaning”.
According to Ellis (2008), perhaps the best way to achieve such principle is to teach
following a ___________ approach.
