The baryon halo of the milky way: A fossil record of its formation

Astronomers believe that the baryon (stellar) halo of the Milky Way retains a fossil imprint of how it was formed. But a vast literature shows that the struggle to interpret the observations within a consistent framework continues. The evidence indicates that the halo has built up through a process of accretion and merging over billions of years, which is still going on at a low level. Future satellite missions to derive three-dimensional space motions and heavy element (metal) abundances for a billion stars will disentangle the existing web and elucidate how galaxies like our own came into existence.     

The dark halo of the milky Way

Most of the matter in the Milky Way is invisible to astronomers. Precise numbers are elusive, but it appears that the dark component is 20 times as massive as the visible disk of stars and gas. This dark matter is distributed in space differently than the stars, forming a vast, diffuse halo, more spherical than disklike, which occupies more than 1000 times the volume of the disk of stars. The composition of this dark halo is unknown, but it may comprise a mixture of ancient, degenerate dwarf stars and exotic, hypothetical elementary particles.     

传统农类专业发展新出路:与县域经济对接

分析传统农类专业在当前所遇到的困境与问题，在此基础上，论证了农类专业与县域经济对接的必要性与可行性，进而归纳了实践中两者对接的几种基本途径，为传统农类专业改造与改革提供一种理论思路。     

生态园林观及其实施发展途径

本文在综合前人有关生态园林论述的基础上，对发展的生态园林内涵作了进一步的补充和分析探讨，并认为要发展生态园林不仅要加深理论认识，更重要的是应该发展一些生态方法在园林中的应用，促进生态园林观的真正实施和发展。本文提出应用长期规划、整体控制下的景观规划和动态规划等生态规划的方法，并提出应用风险-效益综合预评价的方法来进行设计方案的多方案选优决策。     

新农村建设的有效途径——由两地新农村建设理事会引发的思考

本文报道了含山县林头镇陈墩村及望江县高土镇农口村上湾组的两个新农村建设理事会的运作情况,在赞许这一新生事物的同时,分析了它存在的问题,并提出了对其科学定位,加强管理及引导的对策和建议。     

探索发挥大学生自我教育作用的新途径

提高大学生自我意识水平,积极发挥自我教育作用,就是坚持以学生为主体,充分调动学生的内在积极性和主动性,发挥学生的聪明才智和各种潜能,通过大学生自我教育的作用,实现思想转化和行为控制.而高校德育教育传统模式的弊端之一,就是忽视学生自我教育的积极作用,"我说你听"是我们沿用几十年的做法,也是我们习惯了的做法.在新形势面前,要想保证高校德育工作发挥其应有的职能,切实提高德育工作的实效性,必须转变观念,提高对学生自我教育重要性和必要性的认识,积极探索新途径,充分发挥大学生自我教育的重要作用.     

蟹爪兰的新式嫁接和造型

蟹爪兰传统嫁接方法单一且成活率低,新式嫁接采用仙人掌茎节的侧面和正面选择有刺座的部位,以刺座为中心进行嫁接和造型,提高了嫁接成活率,获得了较好的效果.     

Lipid research. Possible new way to lower cholesterol

Clinicians may soon be able to mount a multipronged attack against cholesterol, the artery-clogging lipid whose buildup in the body is a major contributor to heart attacks and other cardiovascular diseases. In work reported on page 1524, a team has pinpointed a biological master switch in mice that controls three pathways that work together to both rid the body of excess cholesterol and prevent its absorption from the intestine. The work suggests a new mechanism for reducing cholesterol, for example, with drugs that turn up the activity of the master switch, a protein known as the retinoid X receptor.     

A new way to keep immune cells in check

To avoid being attacked by the immune system, normal cells carry proteins on their surfaces that mark them as "self." Until now, researchers have identified only one type of self marker: so-called class I major histocompatibility complex proteins. Now, on page 2051, a team reports that macrophages, the immune system's scavenger cells, recognize a different inhibitory signal--a protein called CD47. The findings also shed light on the role of CD47, a surface protein present on basically every cell type--and long a molecule in search of a function.