QUES: Most fatty acids are non-essential, meaning the body can produce them as needed, generally from other fatty acids and always by expending energy to do so. However, in humans, at least two fatty acids are essential and must be included in the diet. An appropriate balance of essential fatty acidsomega-3 and omega-6 fatty acidsseems also important for health, although definitive experimental demonstration has been elusive. Both of these "omega" long-chain polyunsaturated fatty acids are substrates for a class of eicosanoids known as prostaglandins, which have roles throughout the human body. They are hormones, in some respects. The omega-3 eicosapentaenoic acid (EPA), which can be made in the human body from the omega-3 essential fatty acid alpha-linolenic acid (ALA), or taken in through marine food sources, serves as a building block for series 3 prostaglandins (e.g., weakly inflammatory PGE3). The omega-6 dihomo-gamma-linolenic acid (DGLA) serves as a building block for series 1 prostaglandins (e.g. anti-inflammatory PGE1), whereas arachidonic acid (AA) serves as a building block for series 2 prostaglandins (e.g. pro-inflammatory PGE 2). Both DGLA and AA can be made from the omega-6 linoleic acid (LA) in the human body, or can be taken in directly through food. An appropriately balanced intake of omega-3 and omega-6 partly determines the relative production of different prostaglandins, which is one reason why a balance between omega-3 and omega-6 is believed important for cardiovascular health. In industrialized societies, people typically consume large amounts of processed vegetable oils, which have reduced amounts of the essential fatty acids along with too much of omega-6 fatty acids relative to omega-3 fatty acids.

At least how many fatty acids are essential to the human health and have to be consumed rather than produced by the body?
What is the answer?
ANS: two
QUES: Han Chinese farmers were resettled from north China by the Qing to the area along the Liao River in order to restore the land to cultivation. Wasteland was reclaimed by Han Chinese squatters in addition to other Han who rented land from Manchu landlords. Despite officially prohibiting Han Chinese settlement on the Manchu and Mongol lands, by the 18th century the Qing decided to settle Han refugees from northern China who were suffering from famine, floods, and drought into Manchuria and Inner Mongolia so that Han Chinese farmed 500,000 hectares in Manchuria and tens of thousands of hectares in Inner Mongolia by the 1780s. Qianlong allowed Han Chinese peasants suffering from drought to move into Manchuria despite him issuing edicts in favor of banning them from 17401776. Chinese tenant farmers rented or even claimed title to land from the "imperial estates" and Manchu Bannerlands in the area. Besides moving into the Liao area in southern Manchuria, the path linking Jinzhou, Fengtian, Tieling, Changchun, Hulun, and Ningguta was settled by Han Chinese during the Qianlong Emperor's rule, and Han Chinese were the majority in urban areas of Manchuria by 1800. To increase the Imperial Treasury's revenue, the Qing sold formerly Manchu only lands along the Sungari to Han Chinese at the beginning of the Daoguang Emperor's reign, and Han Chinese filled up most of Manchuria's towns by the 1840s according to Abbe Huc.

Who was the emperor in the later half of the 18th century?
What is the answer?
ANS: Qianlong
QUES: During this period Boston flourished culturally as well, admired for its rarefied literary life and generous artistic patronage, with members of old Boston familieseventually dubbed Boston Brahminscoming to be regarded as the nation's social and cultural elites.

Who came to be known as the nation's social elites?
What is the answer?
ANS:
Boston Brahmins