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Abrupt transfer of rainbow trout from freshwater to 65% seawater caused transient disturbances in extracellular fluid ionic composition, but homeostasis was reestablished 48 h posttransfer. Intestinal fluid chemistry revealed early onset of drinking and slightly delayed intestinal water absorption that coincided with initiation of NaC1 absorption and HC[O.sup.-.sub.3] secretion. Suggestive of involvement in osmoregulation, relative mRNA levels for vacuolar [H.sup.+]-ATPase (V-ATPase), [Na.sup.+]-[K.sup.+]-ATPase, [Na.sup.+]/[H.sup.+] exchanger 3 (NHE3), [Na.sup.+]-HC[O.sup.-.sub.3] cotransporter 1, and two carbonic anhydrase (CA) isoforms [a general cytosolic isoform trout cytoplasmic CA (tCAc) and an extracellular isoform trout membrane-bound CA type IV (tCAIV)], were increased transiently in the intestine following exposure to 65% seawater. Both tCAc and tCAIV proteins were localized to apical regions of the intestinal epithelium and exhibited elevated enzymatic activity after acclimation to 65% seawater. The V-ATPase was localized to both basolateral and apical regions and exhibited a 10-fold increase in enzymatic activity in fish acclimated to 65% seawater, suggesting a role in marine osmoregulation. The intestinal epithelium of rainbow trout acclimated to 65% seawater appears to be capable of both basolateral and apical [H.sup.+] extrusion, likely depending on osmoregulatory status and intestinal fluid chemistry. water absorption; HC[O.sup.-.sub.3] secretion; intestinal [H.sup.+] transport; tCAIV; tCAc

Speakers in this symposium presented examples of respiratory regulation that broadly illustrate principles of evolution from whole organ to genes. The swim bladder and lungs of aquatic and terrestrial organisms arose independently from a common primordial 'respiratory pharynx' but not from each other. Pathways of lung evolution are similar between crocodiles and birds but a low compliance of mammalian lung may have driven the development of the diaphragm to permit lung inflation during inspiration. To meet the high oxygen demands of flight, bird lungs have evolved separate gas exchange and pump components to achieve unidirectional ventilation and minimize dead space. The process of 'screening' (removal of oxygen from inspired air prior to entering the terminal units) reduces effective alveolar oxygen tension and potentially explains why nonathletic large mammals possess greater pulmonary diffusing capacities than required by their oxygen consumption. The 'primitive' central admixture of oxygenated and deoxygenated blood in the incompletely divided reptilian heart is actually co-regulated with other autonomic cardiopulmonary responses to provide flexible control of arterial oxygen tension independent of ventilation as well as a unique mechanism for adjusting metabolic rate. Some of the most ancient oxygen-sensing molecules, i.e., hypoxia-inducible factor-1alpha and erythropoietin, are up-regulated during mammalian lung development and growth under apparently normoxic conditions, suggesting functional evolution. Normal alveolarization requires pleiotropic growth factors acting via highly conserved cell-cell signal transduction, e.g., parathyroid hormone-related protein transducing at least partly through the Wingless/int pathway. The latter regulates morphogenesis from nematode to mammal. If there is commonality among these diverse respiratory processes, it is that all levels of organization, from molecular signaling to structure to function, co-evolve progressively, and optimize an existing gas-exchange framework.

Traditionally the process of respiration is divided into three phases: (1) cellular respiration, (2) transport of respiratory gases and (3) ventilation of the gas exchange organs (breathing). Thereby organisms assimilate chemical energy from the environment, and within their cells transfer it from molecule to molecule in a stepwise fashion. Although studied separately, these phases represent a continuum and cellular respiration in all life forms has much in common. Ironically, these respiratory foci have been artificially delineated by their own practitioners, who tend to publish in their own journals, and attend their own conferences. The goal of modern respiratory biology should be to understand biological connectivity and complexity by viewing an organism as a series of interconnecting systems from molecule to ecosystem. The future of science in general, and biology in particular, lies in disciplinary networking: combining the results of traditional disciplines to better understand the whole. Because of its universality, Respiratory Biology can best provide this bridge and improve interdisciplinary studies in biology generally. To this end, the First International Congress of Respiratory Biology was held from August 14 to 16, 2006, at Bonn, Germany. As evident from the success of this inaugural meeting, these are exciting times for Respiratory Biology. The explosion of 'X-omics' and systems biology, the powerful genetic approaches to disease treatment, and the long-standing and newly emerging questions in evolutionary biology and ecology; all portend a continuing role of respiratory biology as a key integrative discipline.

The formulation of the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD) Improvement Committee's applied air dispersion model is described. This is the first of two articles describing the model and its performance. Part I includes AERMOD's characterization of the boundary layer with computation of the Monin--Obukhov length, surface friction velocity, surface roughness length, sensible heat flux, convective scaling velocity, and both the shear- and convection-driven mixing heights. These parameters are used in conjunction with meteorological measurements to characterize the vertical structure of the wind, temperature, and turbulence. AERMOD's method for considering both the vertical inhomogeneity of the meteorological characteristics and the influence of terrain are explained. The model's concentration estimates are based on a steady-state plume approach with significant improvements over commonly applied regulatory dispersion models. Complex terrain influences are provided by combining a horizontal plume state and a terrain-following state. Dispersion algorithms are specified for convective and stable conditions, urban and rural areas, and in the influence of buildings and other structures. Part II goes on to describe the performance of AERMOD against 17 field study databases.

The performance of the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD) Improvement Committee's applied air dispersion model against 17 field study databases is described. AERMOD is a steady-state plume model with significant improvements over commonly applied regulatory models. The databases are characterized, and the performance measures are described. Emphasis is placed on statistics that demonstrate the model's abilities to reproduce the upper end of the concentration distribution. This is most important for applied regulatory modeling. The field measurements are characterized by fiat and complex terrain, urban and rural conditions, and elevated and surface releases with and without building wake effects. As is indicated by comparisons of modeled and observed concentration distributions, with few exceptions AERMOD's performance is superior to that of the other applied models tested. This is the second of two articles, with the first describing the model formulations.

The performance of the Complex Terrain Dispersion Model developed by the Environmental Protection Agency for plume simulations in complex topography is evaluated. SO2 field-study data obtained from a generating station with complex topography and having a specific area is employed in the study. The measurements are conducted on an hourly and daily basis under both stable and unstable conditions. Results indicate that further research is needed to accurately simulate lateral plume spread near complex terrain at convective conditions.

An advanced plume model developed by the Environmental Protection Agency for complex-terrain applications is presented. The Complex Terrain Dispersion Model consists of three independent components and is capable of analyzing the relation between measured meteorological data and pollutants by means of probability density functions. This model is radical departure from traditional steady-state models used in the simulation of plume behavior.

Pro-active, proficient and pro-people policies in environmental projects effectively communicate project goals, lead public opinion, build sound community relations, and curb negative public reaction. The confrontational and contrived philosophy of unilateral decisions and their subsequent defence evokes public skepticism, outrage, and resistance. Risk communication is successful when data are valid and technically accurate, community concerns are genuine, and key messages are pretested through peer-review and target-audience focus groups.