Table of contents

We review the field of high temperature cuprate superconductors, with emphasis on the nature of their electronic properties. After a general overview of experiment and theory, we concentrate on recent results obtained by angle resolved photoemission, inelastic neutron scattering, and optical conductivity, along with various proposed explanations for these results. We conclude by reviewing efforts which attempt to identify the energy savings involved in the formation of the superconducting ground state.

In this introduction to the burgeoning field of econophysics, we review the application of self-organized criticality to economics, the Cont–Bouchaud percolation model, multiple-strategy agent-based models of financial markets, the minority game, and log-periodic precursors to financial crashes.

Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational collapse characterized by the runaway growth of a central density peak that evolves towards a singularity. As long as collapse can occur, rotation and magnetic fields do not change this qualitative behaviour. The result is that a very small embryonic star or protostar forms and grows by accretion at a rate that is initially high but declines with time as the surrounding envelope is depleted. Rotation causes some of the remaining matter to form a disk around the protostar, but accretion from protostellar disks is not well understood and may be variable. Most, and possibly all, stars form in binary or multiple systems in which gravitational interactions can play a role in redistributing angular momentum and driving episodes of disk accretion. Variable accretion may account for some peculiarities of young stars such as flareups and jet production, and protostellar interactions in forming systems of stars will also have important implications for planet formation. The most massive stars form in the densest environments by processes that are not yet well understood but may include violent interactions and mergers. The formation of the most massive stars may have similarities to the formation and growth of massive black holes in very dense environments.

Venus is a planet that is similar to Earth in terms of some important planetary parameters (size, mass, position in the solar system, presence of atmosphere) and different in terms of other, equally important ones (absence of an intrinsic magnetic field, large atmospheric mass, carbon dioxide composition of the atmosphere, lack of water, very high surface pressure and temperature). The surface morphology of Venus is dominated by the signatures of basaltic volcanism and tectonic deformation. Other geological processes such as impact cratering, aeolian activity and gravity-driven down-slope mass movement, although active on the planet, are certainly of subordinate significance. Venusian volcanism resulted in the formation of vast regional plains, occupying most of the planet's surface, and in the building of numerous volcanic edifices. Venusian tectonic deformation was both compressional and extensional. Scales and, periodically, rates of Venusian volcanism and tectonism were comparable to those on Earth. But Venus shows no evidence of the global plate-tectonic style so dominant in the geology of Earth. The morphological record seen in the Magellan radar images of Venus extends back into geological history not earlier than about 0.5–1 billion years. It is represented by a sequence of units from highly tectonized tessera and densely fractured plains, whose compositional nature is unclear, through moderately deformed basaltic lava plains, and then to only locally deformed basaltic plains and edifices. In the beginning of the time period during which this sequence formed, the rates of volcanic and tectonic activity were significantly higher than in the subsequent time extending to the present. This change in volcanic and tectonic activity may correspond to a change in the convection style in the mantle of Venus.

Small-angle scattering (SAS) of x-rays and neutrons is a fundamental tool in the study of biological macromolecules. The major advantage of the method lies in its ability to provide structural information about partially or completely disordered systems. SAS allows one to study the structure of native particles in near physiological environments and to analyse structural changes in response to variations in external conditions.

In this review we concentrate on SAS studies of isotropic systems, in particular, solutions of biological macromolecules, an area where major progress has been achieved during the last decade. Solution scattering studies are especially important, given the challenge of the 'post-genomic' era with vast numbers of protein sequences becoming available. Numerous structural initiatives aim at large-scale expression and purification of proteins for subsequent structure determination using x-ray crystallography and NMR spectroscopy. Because of the requirement of good crystals for crystallography and the low molecular mass requirement of NMR, a significant fraction of proteins cannot be analysed using these two high-resolution methods. Progress in SAS instrumentation and novel analysis methods, which substantially improve the resolution and reliability of the structural models, makes the method an important complementary tool for these initiatives.

The review covers the basics of x-ray and neutron SAS, instrumentation, mathematical methods used in data analysis and major modelling techniques. Examples of applications of SAS to different types of biomolecules (proteins, nucleic acids, macromolecular complexes, polyelectrolytes) are presented. A brief account of the new opportunities offered by third and fourth generation synchrotron radiation sources (time-resolved studies, coherent scattering and single molecule scattering) is also given.

Specific chemical reactions take place in a cluster when it impinges on a solid surface. These intracluster processes ranging from vibrational excitation to atomic rearrangements are called 'cluster-impact' processes, the features of which change specifically with the collision energy and the cluster size. The specificity of the cluster-impact processes arises from impulsive energy transmission to specific modes of the cluster followed by rapid energy redistribution among other degrees of freedom, including those of the surface. In this review, citing several representative collision systems (cluster + surface), we explain the features of a cluster-impact process by dividing the collision energy into several energy ranges, in each of which a characteristic feature is manifested; high vibrational excitation of fullerenes in the lowest energy range, mechanical bond splitting of and a four-centre reaction between N₂ and O₂ in a higher energy range, etc.

In recent years, a number of factors have prompted change in the teaching of physics. These factors include: 1) results from physics education research, 2) technology as a teaching tool, 3) a decline in the number of students choosing physics as a major field of study, and 4) concerns about the physics content knowledge of different groups of students with particular career goals. These factors and the changes that have resulted are discussed, including a greater focus on conceptual understanding and the cognitive skills required to understand and apply physics concepts, interactive engagement methods, teaching physics in different contexts, and the use of technology.