1. I ntroduction 2. P artitioning of O2 and CO2 Exchange Across the Respiratory Surfaces 2.1. P rimitive Ray‐Finned Fishes (Actinopterygii) 2.2. L obe‐Finned Fishes (Sarcopterygii) 2.3. J awless Fishes (Agnatha) 3. B lood O2 Transport 3.1. G eneral Principles of Hb Function 3.2. F actors AVecting the ArterioVenous O2 DiVerence 3.3. S urvey of Extant Primitive Fishes 4. T ransport and Eliminatio...

Along with replication and mutability, living beings are set apart from the mineral background they inhabit by their metabolism—their ability to catalyse chemical reactions. Since Linus Pauling first proposed that these reactions are made pos­ sible by enzymes that recognize and bind tightly to their substrates at a crucial transi­ tion point [1], it has become increasingly clear that understan...

Mutual fund providers serve two principals with opposing interests: their owners, who want them to maximize profits, and their fund shareholders, who want them to maximize fund returns. I investigate what role is played by customer power and information, as well as by competition among fund providers in influencing the balance of power between these two opposing principals. Using a data set of ...

Novel artificial genetic systems with twelve bases instead of four. 1 Bacteria that can be programmed to take photographs 2 or form visible patterns. 3 Cells that can count the number of times they divide. 4 A live polio virus " created from scratch using mail-order segments of DNA and a viral genome map that is freely available on the Internet. " 5 These are some of the remarkable, and occasio...

study of fishes on aquatic ecosystems in many respects, including ecology, behavior, biology, conservation and management of water resources, exploitation of resources and training are important. so in the autumn 2011, the population structure of barilius mesopotamicus was studied. in this order, 69 samples of the mentioned fish from seimareh (34 samples), changoleh (20 samples) and siahgave (1...

Time to split A yeast cell can stand out from the crowd by hastening or delaying meiosis. A yeast master regulator protein helps cells determine when to enter meiosis, as Iftach Nachman, Aviv Regev, and Sharad Ramanathan (Harvard University, Cambridge, MA) report. Starvation spurs yeast to begin meiosis. But the process is complicated and irreversible, and cells that start too early or too late...