(1) extra-embryonic blood vessels ---blood island: at the middle of 3 rd week, wall of the yolk sac mesenchyma proliferate and form isolated cell clusters, the peripheral cell become flattened and differentiate into endothelial cell to from endothelial tube; central located cells are detached and develop into primitive blood cells(blood stem cell)

“Any subject can by taught effectively to any child at any stage of development

Substitutivity of Equivalence Let A,M and N be wffs and let AMN be the result of replacing M by N at zero or more occurrences (henceforth called designate occurrences) of M in A. 1. AMN is a wff. 2. If |= M ≡ N then |= A ≡ AMN

Linking Vowel to Vowel If our lips are round at the end of the first word, we insert a / / sound: We write it like this: too often who is so I do all We say it like this: toowoften whowis sowI dowall

Why use phonemic symbols? The alphabet which we use to write English has 26 letters but (British) English has 44 sounds. Inevitably, English spelling is not a reliable guide to pronunciation because Some letters have more than one sound Sometimes letters are not pronounced at all The same sound may be represented by different letters

Deployment and Geometry Maintenance Deployment and Geometry Maintenance  Deployable Membranes Used for solar arrays, sunshields, decoys Being researched for apertures starting at RF and eventually going to optical

Ionization and Conduction in a High-pressure Plasma A normal gas at T <3000K is a good electrical insulator, because there are almost no ∼ free electrons in it. For pressure

Suppose we want to move a satellite in a circular orbit to a position ∆ϑ apart in the same orbit, in a time ∆t (assumed to be several orbital times at least). The general approach is to transfer to a lower (for positive ∆ϑ ) or higher (for ∆ϑ < 0 ) nearby

The safe and reliable long-term disposal of solid waste residues is an important component of integrated waste management. Solid waste residues are waste components that are not recycled, that remain after processing at a materials recovery facility, or that remain after the recovery of conversion products and/or energy. Historically, solid waste has been placed in the soil in the earth's surface or deposited in the oceans. Although ocean dumping of municipal solid waste was officially abandoned in the United States in 1933, it is now argued that many of the wastes now placed in landfills or on land could be used

Chapter 2 Basic Analytical Tools 1. General Equilibrium Analysis一般均衡法 1) GEA means analyzing two or more than two related markets at the same time(eg. Export Market and Import Market, Goods Market and Factor Market) 2) We usually use the PPF and CICas the basic tools in the general equilibrium analysis of international trade