Partially Dual variables in SU(2) Yang-Mills Theory

We propose a reformulation of SU(2) Yang-Mills theory in terms of new variables. These variables are appropriate for describing the theory in its infrared limit, and indicate that it admits knotlike configurations as stable solitons. As a consequence we arrive at a dual picture of the Yang-Mills theory where the short distance limit describes asymptotically free, massless point gluons and the large distance limit describes extended, massive knotlike solitons.Comment: 4 pages, revtex twocolum

Aspects of Electric and Magnetic Variables in SU(2) Yang-Mills Theory

We introduce a novel decomposition of the four dimensional SU(2) gauge field. This decomposition realizes explicitely a symmetry between electric and magnetic variables, suggesting a duality picture between the corresponding phases. It also indicates that at large distances the Yang-Mills theory involves a three component unit vector field, a massive Lorentz vector field, and a neutral scalar field that condenses which yields the mass scale. Our results are consistent with the proposal that the physical spectrum of the theory contains confining strings which are tied into stable knotted solitons.Comment: we have made substantial improvement

Crystal structure of the ZP-N domain of ZP3 reveals the core fold of animal egg coats

Species-specific recognition between the egg extracellular matrix (zona pellucida) and sperm is the first, crucial step of mammalian fertilization. Zona pellucida filament components ZP3 and ZP2 act as sperm receptors, and mice lacking either of the corresponding genes produce oocytes without a zona pellucida and are completely infertile. Like their counterparts in the vitelline envelope of non-mammalian eggs and many other secreted eukaryotic proteins, zona pellucida subunits polymerize using a 'zona pellucida (ZP) domain' module, whose conserved amino-terminal part (ZP-N) was suggested to constitute a domain of its own. No atomic structure has been reported for ZP domain proteins, and there is no structural information on any conserved vertebrate protein that is essential for fertilization and directly involved in egg-sperm binding. Here we describe the 2.3 ångström (A) resolution structure of the ZP-N fragment of mouse primary sperm receptor ZP3. The ZP-N fold defines a new immunoglobulin superfamily subtype with a beta-sheet extension characterized by an E' strand and an invariant tyrosine residue implicated in polymerization. The structure strongly supports the presence of ZP-N repeats within the N-terminal region of ZP2 and other vertebrate zona pellucida/vitelline envelope proteins, with implications for overall egg coat architecture, the post-fertilization block to polyspermy and speciation. Moreover, it provides an important framework for understanding human diseases caused by mutations in ZP domain proteins and developing new methods of non-hormonal contraception

An STM – SEM setup for characterizing photon and electron induced effects in single photovoltaic nanowires

Vertical arrays of semiconductor nanowires show great potential for material-efficient and high-performance solar cells. The characterization and correlation between material structure and properties of the individual nanowires are crucial for the continued performance improvement of such devices. In this work, we developed a method with a scanning tunneling microscope (STM) probe inside a scanning electron microscope (SEM) to enable the studies of single photovoltaic nanowires. The STM probe is used to contact individual nanowires in ensembles. We combine the STM-SEM with an in situ light emitting diode (LED) illumination source to study both the electrical and photovoltaic properties of vertical GaAs nanowires with radial p-i-n junctions. We also illustrate that the local charge separation ability within the nanowires can be studied by electron beam induced current (EBIC) measurements. The in situ SEM setup allows the correlation between properties and nanowire structure. The data show that the quality of the electrical contact to the semiconductor nanowire is crucial to be able to investigate the inherent properties of the nanowires. We have established a procedure to make high-quality ohmic contacts to the nanowires with the STM probe. We also show that the effect of mechanical strain on the electrical properties can be investigated by the STM-SEM setup

Statistical risk warnings in gambling

Gambling is considered a public health issue by many researchers, similarly to alcohol or obesity. Statistical risk warnings on gambling products can be considered a public health intervention that encourages safer gambling while preserving freedom of consumer choice. Statistical risk warnings may be useful to gamblers, given that net gambling losses are the primary driver of harm and that gambling products vary greatly in the degree to which they facilitate losses. However, there is some doubt as to whether statistical risk warnings are, in their current form, effective at reducing gambling harm. Here, we consider current applications and evidence, discuss product-specific issues around a range of gambling products and suggest future directions. Our primary recommendation is that current statistical risk warnings can be improved and also applied to a wider range of gambling products. Such an approach should help consumers to make more informed judgements and potentially encourage gambling operators to compete more directly on the relative ‘price’ of gambling products

Spin-Charge Separation, Conformal Covariance and the SU(2) Yang-Mills Theory

In the low energy domain of four-dimensional SU(2) Yang-Mills theory the spin and the charge of the gauge field can become separated from each other. The ensuing field variables describe the interacting dynamics between a version of the O(3) nonlinear $\sigma$-model and a nonlinear Grassmannian $\sigma$-model, both of which may support closed knotted strings as stable solitons. Lorentz transformations act projectively in the O(3) model which breaks global internal rotation symmetry and removes massless Goldstone bosons from the particle spectrum. The entire Yang-Mills Lagrangian can be recast into a generally covariant form with a conformally flat metric tensor. The result contains the Einstein-Hilbert Lagrangian together with a nonvanishing cosmological constant, and insinuates the presence of a novel dimensionfull parameter in the Yang-Mills theory.Comment: some misprints in equations correcte

Glueballs, closed fluxtubes and eta(1440)

The $eta_L(1410)$ component of the $\eta(1440)$ pseudoscalar has strong affinity for glue. But its mass is incompatible with lattice simulations that predict a much higher value for the $0^{-+}$ glueball. As a consequence it has been suggested that $\eta_L(1410)$ could signal physics beyond the Standard Model. Here we argue that if glueballs are closed gluonic fluxtubes then $\eta_L(1410)$ is a prime candidate for the $0^{-+}$ glueball. Furthermore, in the absence of parity violating terms its mass should be degenerate with that of the $0^{++}$ glueball. We also suggest that the decay properties of such glueballs could be employed as probes for extra dimensions.Comment: 11 page

Modelling the Spatial Dynamics of Culture Spreading in the Presence of Cultural Strongholds

Cultural competition has throughout our history shaped and reshaped the geography of boundaries between humans. Language and culture are intimately connected and linguists often use distinctive keywords to quantify the dynamics of information spreading in societies harbouring strong culture centres. One prominent example, which is addressed here, is Kyoto's historical impact on Japanese culture. We construct a first minimal model, based on shared properties of linguistic maps, to address the interplay between information flow and geography. In particular, we show that spreading of information over Japan in the pre-modern time can be described as a Eden growth process, with noise levels corresponding to coherent spatial patches of sizes given by a single days walk, and with patch-to-patch communication time comparable to the time between human generations.Comment: 5 pages, 4 figure

Limits to the muon flux from WIMP annihilation in the center of the Earth with the AMANDA detector

A search for nearly vertical up-going muon-neutrinos from neutralino annihilations in the center of the Earth has been performed with the AMANDA-B10 neutrino detector. The data sample collected in 130.1 days of live-time in 1997, ~10^9 events, has been analyzed for this search. No excess over the expected atmospheric neutrino background is oberved. An upper limit at 90% confidence level on the annihilation rate of neutralinos in the center of the Earth is obtained as a function of the neutralino mass in the range 100 GeV-5000 GeV, as well as the corresponding muon flux limit.Comment: 14 pages, 11 figures. Version accepted for publication in Physical Review