مقالات

Acemoglu and Robinson have made an important contribution to the debate as to why similar-looking nations differ so greatly in their economic and political development. Through a broad multiplicity of historical examples, they show how institutional developments, sometimes based on very accidental circumstances, have had enormous consequences. The openness of a society, its willingness to permit creative destruction, and the rule of law appear to be decisive for economic development

As one of the most famous economists of the twentieth century, Paul Anthony Samuelson revolutionized many branches of economic theory. As a diligent student of his predecessors, he reconstructed their economic analyses in the mathematical idiom he pioneered. Out of Samuelson’s more than eighty articles, essays, and memoirs, the editors of this collection have selected seventeen. Twelve are mathematical reconstructions of some of the most famous work in the history of economic thought: work by David Hume, Francois Quesnay, Adam Smith, Karl Marx, and others. One is a methodological essay defending the Whig history that Samuelson was sometimes accused of promulgating; two deal with the achievements of Joseph Schumpeter and Denis Robertson; and two review theoretical developments of his own time
Keynesian economics and monopolistic competition. The collection provides reader  with a sense of the depth and breadth of Samuelson’s contributions to the study of the history of economics.

به طور کلی محیط زیست به همه محیط هایی که در آنها زندگی جریان دارد گفته می شود. مجموعه ای از عوامل فیزیکی خارجی و موجودات زنده که با هم در کنش هستند محیط زیست را تشکیل می دهند و بر رشد و نمو و رفتار موجودات تأثیر می گذارند. مشکل آلودگی محیط زیست امروز جهان، مشکل تنها یک کشور و یا یک قلمرو خاص نیست، بلکه مشکل کل جهان است که دربردارنده مسائل مختلفی از جمله آلودگی آب و هوا، گرم شدن کره زمین، بالا آمدن سطح آب دریاها، انهدام گونه های گیاهی و جانوری، فرسایش لایه ازن، تخریب جنگل ها، باران های اسیدی، آلودگی های صوتی و آزمایش های هسته ای است.
آغاز موج توجه عمومی به مسائل محیط زیستی طی دهه 1960 به وقوع پیوست و تمرکز عمده این توجهات بر آلودگی های صنعتی به واسطه رشد روز افزون اقتصادهای صنعتی بود. آلودگی، جریان ورود پسماندها و مواد زاید ناشی از فعالیت های اقتصادی به محیط زیست است. در واقع آلودگی ناشی از فرآیند تولید و مصرف است که در تبدیل عوامل تولید به محصول ایجاد می شود. طبیعت فقط تا حدودی قادر است بین ورودی و خروجی و پسماند تعادل ایجاد کند، به عبارت دیگر توان بازیافت طبیعت محدود است که این توان با افزایش دخالت انسان در طبیعت به میزان زیادی کاهش مییابد. مهمترین آلوده کننده های هوا شامل مونوکسید کربن، دیاکسید کربن، اکسیدهای گوگرد، ذرات معلق در هوا و ازن هستند.

“Economics is a study of mankind in the ordinary business of life.” So wrote Alfred Marshall, the great 19th-century economist, in his textbook, Principles of Economics. Although we have learned much about the economy since Marshall’s time, this definition of economics is as true today as it was in 1890, when the first edition of his text was published. Why should you, as a student at the beginning of the 21st century, embark on the study of economics? There are three reasons.
The first reason to study economics is that it will help you understand the world in which you live. There are many questions about the economy that might spark your curiosity. Why are apartments so hard to find in New York City? Why do airlines charge less for a round-trip ticket if the traveler stays over a Saturday night? Why is Johnny Depp paid so much to star in movies? Why are living standards so meager in many African countries? Why do some countries have high rates of inflation while others have stable prices? Why are jobs easy to find in some years and hard to find in others? These are just a few of the questions that a course in economics will help you answer.
The second reason to study economics is that it will make you a more astute participant in the economy. As you go about your life, you make many economic decisions. While you are a student, you decide how many years to stay in school. Once you take a job, you decide how much of your income to spend, how much to save, and how to invest your savings. Someday you may find yourself running a small business or a large corporation, and you will decide what prices to charge for your products. The insights developed in the coming chapters will give you a new perspective on how best to make these decisions. Studying economics will not by itself make you rich, but it will give you some tools that may help in that endeavor.