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The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune system in defending the body relies on a dynamic regulatory communications network consisting of millions and millions of cells. Organized into sets and subsets, these cells pass information back and forth like clouds of bees swarming around a hive. The result is a sensitive system of checks and balances that produces an immune response that is prompt, appropriate, effective and self-limiting. At the heart of the immune system is the ability to distinguish between self and non-self. When immune defenders encounter cells or organisms carrying foreign or non-self molecules, the immune troops move quickly to eliminate the invaders. Virtually every body cell carries distinctive molecules that identify it as self. The body’’s immune defenses do not normally attack tissues that carry a self marker. Rather, immune cells and other body cells coexist peaceably in a state known as self-tolerance. When a normally functioning immune system attacks a non-self molecule, the system has the ability to remember the specifics of the foreign body. Upon subsequent encounters with the same species of molecules, the immune system reacts accordingly. With the possible exception of antibodies passed during lactation ( 哺乳期 ), this so-called immune system memory is not inherited. Despite the occurrence of a virus in your family, your immune system must learn from experience with the many millions of distinctive non-self molecules in the sea of microbes in which we live. Learning necessitates producing the appropriate molecules and cells to match up with and counteract each non-self invader. Any substance capable of stimulating an immune response is called an antigen. Tissues or cells from another individual (except an identical twin, whose cells carry identical self-markers ) act as antigens; because the immune system recognizes transplanted tissues as foreign, it rejects them. The body will even reject nourishing proteins unless they are first broken down by the digestive system into their primary, non-antigenic building blocks. An antigen announces its foreignness by means of intricate and characteristic shapes called epitopes( 抗原决定基), which stick out from its surface. Most antigens, even the simplest microbes, carry several different kinds of epitopes on their surface, some may even carry several hundred. Some epitopes will be more effective than others at stimulating an immune response. Only in abnormal situations does the immune system wrongly identify self as non-self and execute a misdirected immune attack. The result can be so-called autoimmune disease. The painful side effects of these diseases are caused by a person’’s immune system actually attacking itself The main idea of the text may be generalized as
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某民用建筑砌体承重结构，底层承重墙厚240mm，上部结构荷载效应：Fk=200kN/m。地质土层为：地面下-0.600m内为填土，重度γ=17.6kN/m3；其下为黏土层，比较厚，重度γ=18.9kN/m3；-1.00m处为地下水位。基础埋深取0.8m，经修正后的地基持力层承载力特征值fa=178kPa。设计该基础(初步拟定基础方案为刚性条形基础)。 如果采用素混凝土基础，可选用的方案有( )。
In a world where bad news has become everyday news, people are turning to an ancient technique to deal with stress: meditation. At meditation centers, prayer groups and yoga studios around the United States, more and more are finding peace of mind by being quiet: Some use meditation to help deal with life changes; others, to process the painful reality of political and social unrest around the world of the type that has been experienced more recently. Stress from the September 11 terrorist attacks is "probably about 70 percent" of the reason one Chicago man started meditating and practicing yoga with his new wife. He became so emotionally affected that he realized he needed help in managing his stress. The yoga classes he takes begin and end with meditation. This "quiet time" helps him feel a lot more relaxed and gives him more breath control. The fact is,though ,that he is not alone. Across the country, many are turning to more meditative exercise as they seek both psychological and physiological relief. In addition to helping people work out their stress, these classes bring people together, in the same way that religious services or other community activities have done in the past. Different schools of meditation teach particular techniques, but they share a common basis―focusing attention on something your mind can return to if you are distracted. This may be the rhythm of breathing, an object such as a candle flame loving kindness, or a repetitive movement, as in walking or t’’ai chi (taiji). Regardless of the specific technique or mode that is followed, meditation has well-documented benefits. Medical research indicates that it causes a sharp decrease in metabolic activity, reduced muscle tension, slower breathing, and a shift from faster brainwaves to slower waves. It also reduces high blood pressure. Practitioners are convinced that meditation is good for health because it relaxes the body. For ages, meditation has been a core practice of many groups meeting in their communal or religious centers. However, let’’s not forget that this is the twenty-first century. So, for those people who are too shy or busy to go to the nearest meditation center, there are Internet sites that offer online guided meditation. One has a variety of meditations from various religious traditions. At another, Jesuit priests post meditations and readings from the Scriptures every day, and at still another, Buddhist and Hindu practitioners include music and visuals to accompany their offerings. These websites allow anyone with a computer access to meditation at any time. The fact is that whether online, at Yoga classes, or at local spiritual centers, more people are turning to the practice of meditation. The author acclaims the benefits of meditation as
The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune system in defending the body relies on a dynamic regulatory communications network consisting of millions and millions of cells. Organized into sets and subsets, these cells pass information back and forth like clouds of bees swarming around a hive. The result is a sensitive system of checks and balances that produces an immune response that is prompt, appropriate, effective and self-limiting. At the heart of the immune system is the ability to distinguish between self and non-self. When immune defenders encounter cells or organisms carrying foreign or non-self molecules, the immune troops move quickly to eliminate the invaders. Virtually every body cell carries distinctive molecules that identify it as self. The body’’s immune defenses do not normally attack tissues that carry a self marker. Rather, immune cells and other body cells coexist peaceably in a state known as self-tolerance. When a normally functioning immune system attacks a non-self molecule, the system has the ability to remember the specifics of the foreign body. Upon subsequent encounters with the same species of molecules, the immune system reacts accordingly. With the possible exception of antibodies passed during lactation ( 哺乳期 ), this so-called immune system memory is not inherited. Despite the occurrence of a virus in your family, your immune system must learn from experience with the many millions of distinctive non-self molecules in the sea of microbes in which we live. Learning necessitates producing the appropriate molecules and cells to match up with and counteract each non-self invader. Any substance capable of stimulating an immune response is called an antigen. Tissues or cells from another individual (except an identical twin, whose cells carry identical self-markers ) act as antigens; because the immune system recognizes transplanted tissues as foreign, it rejects them. The body will even reject nourishing proteins unless they are first broken down by the digestive system into their primary, non-antigenic building blocks. An antigen announces its foreignness by means of intricate and characteristic shapes called epitopes( 抗原决定基), which stick out from its surface. Most antigens, even the simplest microbes, carry several different kinds of epitopes on their surface, some may even carry several hundred. Some epitopes will be more effective than others at stimulating an immune response. Only in abnormal situations does the immune system wrongly identify self as non-self and execute a misdirected immune attack. The result can be so-called autoimmune disease. The painful side effects of these diseases are caused by a person’’s immune system actually attacking itself We know from the text that the immune system
某民用建筑砌体承重结构，底层承重墙厚240mm，上部结构荷载效应：Fk=200kN/m。地质土层为：地面下-0.600m内为填土，重度γ=17.6kN/m3；其下为黏土层，比较厚，重度γ=18.9kN/m3；-1.00m处为地下水位。基础埋深取0.8m，经修正后的地基持力层承载力特征值fa=178kPa。设计该基础(初步拟定基础方案为刚性条形基础)。 墙体下砖放脚，合适的做法有( )。
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