Hypothesis testing is not a straightforward matter in the fossil record and here, too interactions with biology can be extremely profitable. Quite simply, predictions regarding long-term consequences of processes observed in liv­ ing organisms can be tested directly using paleontological data if those liv­ ing organisms have an adequate fossil record, thus avoiding the pitfalls of extrapolative approaches. We hope to see a burgeoning of this interactive effort in the coming years. Framing and testing of hypotheses in paleon­ tological subjects inevitably raises the problem of inferring process from pattern, and the consideration and elimination of a broad range of rival hy­ is an essential procedure here. In a historical science such as potheses paleontology, the problem often arises that the events that are of most in­ terest are unique in the history of life. For example, replication of the metazoan radiation at the beginning of the Cambrian is not feasible. How­ ever, decomposition of such problems into component hypotheses may at least in part alleviate this difficulty. For example, hypotheses built upon the role of species packing might be tested by comparing evolutionary dy­ namics (both morphological and taxonomic) during another global diversi­ fication, such as the biotic rebound from the end-Permian extinction, which removed perhaps 95% of the marine species (see Valentine, this volume). The subject of extinction, and mass extinction in particular, has become important in both paleobiology and biology.

While the ability of animals to learn rhythms is an unquestionable fact, the underlying neurophysiological mechanisms are still no more than conjectures. This monograph explores the requirements of such mechanisms, reviews those previously proposed and postulates a new one based on a direct electric coding of stimulation frequencies. Experi­ mental support for the option taken is provided both at the single neuron and neural network levels. More specifically, the material presented divides naturally into four parts: a description of the experimental and theoretical framework where this work becomes meaningful (Chapter 2), a detailed specifica­ tion of the pacemaker neuron model proposed together with its valida­ tion through simulation (Chapter 3), an analytic study of the behavior of this model when submitted to rhythmic stimulation (Chapter 4) and a description of the neural network model proposed for learning, together with an analysis of the simulation results obtained when varying seve­ ral factors related to the connectivity, the intraneuronal parameters, the initial state and the stimulation conditions (Chapter 5). This work was initiated at the Computer and Information Science Depart­ ment of the University of Massachusetts, Amherst, and completed at the Institut de c Lber n e t Lca of the Universitat Politecnica de Catalunya, Barcelona. Computers at the latter place have adopted Catalan as their mother tongue and thus some computer-made figures in this monograph, specially those in Chapter 5, appear labeled in that tongue.

This volume addresses the question of time from the perspective of the time of nature. Its aim is to provide some insights about the nature of time on the basis of the different uses of the concept of time in natural sciences. Presenting a dialogue between philosophy and science, it features a collection of papers that investigate the representation, modeling and understanding of time as they appear in physics, biology, geology and paleontology. It asks questions such as: whether or not the notions of time in the various sciences are reducible to the same physical time, what status should be given to timescale differences, or what are the specific epistemic issues raised by past facts in natural sciences.

3 of the experience of the last few generations. The group of happily unexperienced events includes large bolide impacts with the Earth. The evidence for the occurrence of such impacts at intervals of some tens of millions of years is quite convincing, and Lyell stands admonished by Hamlet: "There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy. " The role of bolide impacts on the history of life during other portions of the Phanerozoic Eon is less clear (see Raup and Fischer, both this volume), and catastrophic changes unrelated to extraterrestrial processes may have been important (see Holser, this volume). Changes in the later Precambrian biota are still difficult to interpret, in part because the preservation of soft-bodied animals from this period of Earth history is so unusual (see Seilacher, this volume). During the past billion years or so, bolide impacts have exerted a significant effect on the Earth's surface and its inhabitants, but not on its interior. The 3800 Ma rocks at Isua in West Greenland are the oldest terrestrial rocks that are currently available for inspection (see Dymek, this volume). They contain abundant evidence for the operation of chemical and physical processes that are similar to those of the present day. This situation could not have prevailed during the entire 700 Ma preceding the formation of the Isua rocks.

Un romanzo imponente, nel suo spaccare a metà la storia dell'Europa del secondo Novecento per inserirvi dei personaggi che tutto sembrano fuorché inventati. Entriamo nella vicenda nel 1940, quando la Germania, quasi al culmine della sua espansione, raggiunge Parigi. Lì vive la famiglia Malot che, nonostante le spaventose difficoltà, mantiene attiva una scuola di ballo. Nicole Malot e Franz Kessel sono divisi dall'appartenenza ai due schieramenti politici opposti, ma lentamente si scoprono vicini e innamorati. Nel turbinìo degli eventi anche la figura di Joseph Steiner, ricchissimo ebreo, che sta cercando di salvare i suoi sette figli, deportati verso i campi di sterminio, offrendo in cambio della loro vita sette preziosi diamanti.

This book presents theories and techniques for perception of textures by computer. Texture is a homogeneous visual pattern that we perceive in surfaces of objects such as textiles, tree barks or stones. Texture analysis is one of the first important steps in computer vision since texture provides important cues to recognize real-world objects. A major part of the book is devoted to two-dimensional analysis of texture patterns by extracting statistical and structural features. It also deals with the shape-from-texture problem which addresses recovery of the three-dimensional surface shapes based on the geometry of projection of the surface texture to the image plane. Perception is still largely mysterious. Realizing a computer vision system that can work in the real world requires more research and ex­ periment. Capability of textural perception is a key component. We hope this book will contribute to the advancement of computer vision toward robust, useful systems. vVe would like to express our appreciation to Professor Takeo Kanade at Carnegie Mellon University for his encouragement and help in writing this book; to the members of Computer Vision Section at Electrotechni­ cal Laboratory for providing an excellent research environment; and to Carl W. Harris at Kluwer Academic Publishers for his help in preparing the manuscript.

Insects multiply. Destruction reigns. There is dismay, followed by outcry, and demands to Authority. Authority remembers its experts or appoints some: they ought to know. The experts advise a Cure. The Cure can be almost anything: holy water from Mecca, a Government Commis­ sion, a culture of bacteria, poison, prayers denunciatory or tactful, a new god, a trap, a Pied Piper. The Cures have only one thing in common: with a little patience they always work. They have never been known entirely to fail. Likewise they have never been known to prevent the next outbreak. For the cycle of abundance and scarcity has a rhythm of its own, and the Cures are applied just when the plague of insects is going to abate through its own loss of momentum. -Abridged, with insects in place of voles, from C. Elton, 1924, Voles, Mice and Lemmings, with permission of Oxford University Press This book is an enquiry into the "natural rhythms" of insect abundance in forested ecosystems and into the forces that give rise to these rhythms. Forests form unique environ­ ments for such studies because one can find them growing under relatively natural (pri­ meval) conditions as well as under the domination of human actions. Also, the slow growth and turnover rates of forested ecosystems enable us to investigate insect popula­ tion dynamics in a plant environment that remains relatively constant or changes only slowly, this in contrast to agricultural systems, where change is often drastic and frequent.

L'Avro Lancaster era un bombardiere pesante quadrimotore ad ala media progettato e costruito principalmente dall'azienda britannica Avro (A.V. Roe and Company).
Utilizzato dalla RAF a partire dal 1942, assieme all'Handley Page Halifax, fu il principale bombardiere strategico della RAF e delle altre forze aeree dei paesi del Commonwealth.
Venne utilizzato principalmente come bombardiere notturno.