Thisvolumecontainsacollectionofpapersbyinternationalexpertsingeoph- ical ?uid dynamics, based upon presentations at a colloquium held in memory of Pedro Ripa on the ?rst anniversary of his untimely death. They review or present recent developments in hydrodynamic stability theory, Hamiltonian ?uid mechanics,balanceddynamics, waves,vortices,generaloceanographyand the physical oceanography of the Gulf ofCalifornia; all of them subjects in which Professor Ripamadeimportant contributions. His work, but also his friendly spiritandkindnesswerehighly regardedandappreciatedby colleagues and students alike around the world. This book is a tribute to his scienti?c legacy and constitutes a valuable reference for researchers and graduate s- dents interested in geophysical and general ?uid mechanics. Earlyin his career asa physicaloceanographer,Pedro Ripa made two la- mark contributions to geophysical ?uid dynamics. In 1981, he showed that the conservation of the potential vorticity is related to the invariance of the eq- tions of motion under the symmetry transformationsof the labels that identify the ?uid particles. That is, potential vorticity conservation is a consequence, via Noether's theorem, of the particle re-labelling symmetry. Two years later he published a paper entitled "General stability conditions for zonal ?ows in a one-layer model on the beta-plane or the sphere", where he established nec- sary conditions for stability in the shallow water equations, nowadays known as "Ripa's Theorem. " This is one of the very few Arnol'd-like stability con- tions that goes beyond two-dimensional or quasi-geostrophic ?ow, and stands alongside other famous stability criteria in making the foundations of the ?eld.

Over the past two centuries Western culture has largely valorized a particular kind of "good" music--highly serious, wondrously deep, stylistically authentic, heroically created, and strikingly original--and, at the same time, has marginalized music that does not live up to those ideals. In Good Music, John J. Sheinbaum explores these traditional models for valuing music. By engaging examples such as Handel oratorios, Beethoven and Mahler symphonies, jazz improvisations, Bruce Springsteen, and prog rock, he argues that metaphors of perfection do justice to neither the perceived strengths nor the assumed weaknesses of the music in question. Instead, he proposes an alternative model of appreciation where abstract notions of virtue need not dictate our understanding. Good music can, with pride, be playful rather than serious, diverse rather than unified, engaging to both body and mind, in dialogue with manifold styles and genres, and collaborative to the core. We can widen the scope of what music we value and reconsider the conventional rituals surrounding it, while retaining the joys of making music, listening closely, and caring passionately.

Thisvolumecontainsacollectionofpapersbyinternationalexpertsingeoph- ical ?uid dynamics, based upon presentations at a colloquium held in memory of Pedro Ripa on the ?rst anniversary of his untimely death. They review or present recent developments in hydrodynamic stability theory, Hamiltonian ?uid mechanics, balanceddynamics, waves, vortices, generaloceanographyand the physical oceanography of the Gulf ofCalifornia; all of them subjects in which Professor Ripamadeimportant contributions. His work, but also his friendly spiritandkindnesswerehighly regardedandappreciatedby colleagues and students alike around the world. This book is a tribute to his scienti?c legacy and constitutes a valuable reference for researchers and graduate s- dents interested in geophysical and general ?uid mechanics. Earlyin his career asa physicaloceanographer, Pedro Ripa made two la- mark contributions to geophysical ?uid dynamics. In 1981, he showed that the conservation of the potential vorticity is related to the invariance of the eq- tions of motion under the symmetry transformationsof the labels that identify the ?uid particles. That is, potential vorticity conservation is a consequence, via Noether's theorem, of the particle re-labelling symmetry. Two years later he published a paper entitled "General stability conditions for zonal ?ows in a one-layer model on the beta-plane or the sphere," where he established nec- sary conditions for stability in the shallow water equations, nowadays known as "Ripa's Theorem. " This is one of the very few Arnol'd-like stability con- tions that goes beyond two-dimensional or quasi-geostrophic ?ow, and stands alongside other famous stability criteria in making the foundations of the ?eld.

Over the past two centuries Western culture has largely valorized a particular kind of "good" music--highly serious, wondrously deep, stylistically authentic, heroically created, and strikingly original--and, at the same time, has marginalized music that does not live up to those ideals. In Good Music, John J. Sheinbaum explores these traditional models for valuing music. By engaging examples such as Handel oratorios, Beethoven and Mahler symphonies, jazz improvisations, Bruce Springsteen, and prog rock, he argues that metaphors of perfection do justice to neither the perceived strengths nor the assumed weaknesses of the music in question. Instead, he proposes an alternative model of appreciation where abstract notions of virtue need not dictate our understanding. Good music can, with pride, be playful rather than serious, diverse rather than unified, engaging to both body and mind, in dialogue with manifold styles and genres, and collaborative to the core. We can widen the scope of what music we value and reconsider the conventional rituals surrounding it, while retaining the joys of making music, listening closely, and caring passionately.