6D Dyonic String With Active Hyperscalars

We derive the necessary and sufficient conditions for the existence of a Killing spinor in N=(1,0) gauge supergravity in six dimensions coupled to a single tensor multiplet, vector multiplets and hypermultiplets. These are shown to imply most of the field equations and the remaining ones are determined. In this framework, we find a novel 1/8 supersymmetric dyonic string solution with nonvanishing hypermultiplet scalars. The activated scalars parametrize a 4 dimensional submanifold of a quaternionic hyperbolic ball. We employ an identity map between this submanifold and the internal space transverse to the string worldsheet. The internal space forms a 4 dimensional analog of the Gell-Mann-Zwiebach tear-drop which is noncompact with finite volume. While the electric charge carried by the dyonic string is arbitrary, the magnetic charge is fixed in Planckian units, and hence necessarily non-vanishing. The source term needed to balance a delta function type singularity at the origin is determined. The solution is also shown to have 1/4 supersymmetric AdS_3 x S^3 near horizon limit where the radii are proportional to the electric charge.Comment: 28 pages, latex, minor corrections mad

Biochemical Oscillations and Cellular Rhythms: The Molecular Bases of Periodic and Chaotic Behavior

the threads of complexity in chemical systems. The promise of this new activity is particularly rich for macromolecules (including biologically relevant macromolecules), in which opportunities for the existence of many different molecular conformations, each with different properties, are high. At the core of chemical interest in complexity are the two fundamental problems concerning life, that is, trying to understand (i) how collections of molecules can give rise to the varieties of behaviors that characterize cells and organisms and (ii) how individual molecules might have originally assembled into collections that had the characteristics of life (energy dissipation, self-replication, and adaptation). Whether the understanding of complexity at the molecular level will reveal important elements of the structure of life is unclear. We do not know if it is conceptually possible to connect molecular-level processes to organismic behavior deterministically. Certainly, knowing everything about the electronic properties of Si and the operating characteristics of transistors tells very little about the higher level characteristics of computers. Fortunately, there is also the inverse opportunity: learning from biological complexity as a method of stimulating new chemistry. With this opportunity, there is great reason for optimism. Biological systems display such a large number of remarkable capabilities (and capabilities that are so clearly complex) that their analysis will unquestionably be a rich source of models for new areas of chemistry. ANNs are one example of a successful transfer of information about a complex biological system to nonbiological applications. ANNs were developed, in part, as a tool with which to model the brain. To what extent current ANNs do so is a continuing subject of discussion, but the effort to make the connection between ANNs and brains (and to learn from the brain) has unquestionably expanded the capabilities of computation. In this same sense, biology (and perhaps also complex materials) offers examples of complex systems that show types of behavior that are now uncommon in molecular chemistry. One of the opportunities in fundamental chemical research is to learn from biology and to use what is learned to design nonbiological systems that dissipate energy, replicate, and adapt. Whether such systems would model life is moot; they would unquestionably be very interesting and probably very important

Harnessing the social: state, crisis and (big) society

The paper analyses the UK government’s plans to create a social investment market. The Big Society as political economy is understood as a response to three aspects of a multi-faceted, global crisis: a crisis of capital accumulation; a crisis of social reproduction; and, a fiscal crisis of the state. While the neoliberal state is retreating from the sphere of social reproduction, further off-loading the costs of social reproduction onto the unwaged realms of the home and the community, it is simultaneously engaging in efforts to enable this terrain of social reproduction to be harnessed for profit. Key to this process are specific government policies, the creation of new financial institutions and instruments and the introduction of the metric of ‘social value’. Policies ostensibly aimed at resolving the crisis in ways that empower local communities, actually foster further financialisation and a deepening of capitalist disciplinary logics into the social fabric

PYTHIA 6.4 Physics and Manual

The PYTHIA program can be used to generate high-energy-physics `events', i.e. sets of outgoing particles produced in the interactions between two incoming particles. The objective is to provide as accurate as possible a representation of event properties in a wide range of reactions, within and beyond the Standard Model, with emphasis on those where strong interactions play a role, directly or indirectly, and therefore multihadronic final states are produced. The physics is then not understood well enough to give an exact description; instead the program has to be based on a combination of analytical results and various QCD-based models. This physics input is summarized here, for areas such as hard subprocesses, initial- and final-state parton showers, underlying events and beam remnants, fragmentation and decays, and much more. Furthermore, extensive information is provided on all program elements: subroutines and functions, switches and parameters, and particle and process data. This should allow the user to tailor the generation task to the topics of interest.Comment: 576 pages, no figures, uses JHEP3.cls. The code and further information may be found on the PYTHIA web page: http://www.thep.lu.se/~torbjorn/Pythia.html Changes in version 2: Mistakenly deleted section heading for "Physics Processes" reinserted, affecting section numbering. Minor updates to take into account referee comments and new colour reconnection option

Cambridge Monographs in Experimental Biology

and the magnitude of FCT. Because active torque is proportional to n 2 and passive torque to n, the ratio of active to passive torque increases as n increases (Eq. 5), even while both quantities increase individuallẏ The increase in the ratio indicates an enhanced capability for active maneuvers and active stabilization, whereas the increase in FCT adds to passive stability. Thus, increasing wingbeat frequency enhances both maneuverability and stability. Hummingbirds provide an interesting example; males typically have greater wingbeat frequencies (21) and smaller body sizes as compared to females of the same species, potentially conferring a benefit in maneuverability and therefore an advantage in display flights (22) as well as greater stability when experiencing an external perturbation. These benefits are not without cost, because increasing wingbeat frequency increases the inertial and profile power requirements of flapping flight. Finally, the success of our FCT model in predicting yaw deceleration dynamics implies that passive damping may be important to flight control in flying animals across a wide range of body sizes. For example, if a steadily flapping animal experiences a brief perturbation in midstroke, by the time it is prepared to execute a corrective wingbeat, FCT will have eroded much of the effect of the perturbation, regardless of the wingbeat frequency employed by the animal. Thus, FCT provides open loop stability for some aspects of animal flight, reducing its neuromuscular and neurosensory requirements. These are not eliminated, because FCT results in asymmetric forces from symmetric flapping, implying that the animal's muscles must generate asymmetric forces and suggesting neural regulation to enforce symmetry. Furthermore, FCT does not address all the stability problems faced by flying animals. This study is limited to yaw dynamics in hovering or slow-speed flight; FCT is likely to be influential in fast forward flight, but no data are available to test such predictions. More important, a full description of body dynamics involves many factors beyond FCT and includes modes such as pitching and longitudinal dynamics known to be inherently unstable in open loop conditions (23, 24) and subject to active control (25, 26). Finally, yaw damping due to FCT is a feature of flapping flight that is not found in human-made fixed-wing or rotary-wing flyers and may lead to improvements in the stability and maneuverability of biomimetic micro-air vehicles. 11. S. P. Sane, J. Exp. Biol. 206, 4191 (2003). 12. J. R. Usherwood, C. P. Ellington, J. Exp. Biol. 205, 1565 Synonymous mutations do not alter the encoded protein, but they can influence gene expression. To investigate how, we engineered a synthetic library of 154 genes that varied randomly at synonymous sites, but all encoded the same green fluorescent protein (GFP). When expressed in Escherichia coli, GFP protein levels varied 250-fold across the library. GFP messenger RNA (mRNA) levels, mRNA degradation patterns, and bacterial growth rates also varied, but codon bias did not correlate with gene expression. Rather, the stability of mRNA folding near the ribosomal binding site explained more than half the variation in protein levels. In our analysis, mRNA folding and associated rates of translation initiation play a predominant role in shaping expression levels of individual genes, whereas codon bias influences global translation efficiency and cellular fitness. T he theory of codon bias posits that preferred codons correlate with the abundances of iso-accepting tRNAs (1, 2) and thereby increase translational efficiency (3) and accuracy (4). Recent experiments have revealed other effects of silent mutations (5-7). We synthesized a library of green fluorescent protein (GFP) genes that varied randomly in their codon usage, but encoded the same amino acid sequence (8). By placing these constructs in identical regulatory contexts and measuring their expression, we isolated the effects of synonymous variation on gene expression. The GFP gene consists of 240 codons. For 226 of these codons, we introduced random silent mutations in the third base position, while keeping the first and second positions constant We expressed the GFP genes in E. coli using a T7-promoter vector, and we quantified expression by spectrofluorometry. Fluorescence levels varied 250-fold across the library, and they were highly reproducible for each GFP construct (Spearman r = 0.98 between biological replicates)