A tail-like assembly at the portal vertex in intact herpes simplex type-1 virions

Herpes viruses are prevalent and well characterized human pathogens. Despite extensive study, much remains to be learned about the structure of the genome packaging and release machinery in the capsids of these large and complex double-stranded DNA viruses. However, such machinery is well characterized in tailed bacteriophage, which share a common evolutionary origin with herpesvirus. In tailed bacteriophage, the genome exits from the virus particle through a portal and is transferred into the host cell by a complex apparatus (i.e. the tail) located at the portal vertex. Here we use electron cryo-tomography of human herpes simplex type-1 (HSV-1) virions to reveal a previously unsuspected feature at the portal vertex, which extends across the HSV-1 tegument layer to form a connection between the capsid and the viral membrane. The location of this assembly suggests that it plays a role in genome release into the nucleus and is also important for virion architecture

Separable and non-separable multi-field inflation and large non-Gaussianity

In this paper we provide a general framework based on $\delta N$ formalism to estimate the cosmological observables pertaining to the cosmic microwave background radiation for non-separable potentials, and for generic \emph{end of inflation} boundary conditions. We provide analytical and numerical solutions to the relevant observables by decomposing the cosmological perturbations along the curvature and the isocurvature directions, \emph{instead of adiabatic and entropy directions}. We then study under what conditions large bi-spectrum and tri-spectrum can be generated through phase transition which ends inflation. In an illustrative example, we show that large $f_{NL}\sim {\cal O}(80)$ and $\tau_{NL}\sim {\cal O}(20000)$ can be obtained for the case of separable and non-separable inflationary potentials.Comment: 21 pages, 6 figure

Inflationary perturbation theory is geometrical optics in phase space

A pressing problem in comparing inflationary models with observation is the accurate calculation of correlation functions. One approach is to evolve them using ordinary differential equations ("transport equations"), analogous to the Schwinger-Dyson hierarchy of in-out quantum field theory. We extend this approach to the complete set of momentum space correlation functions. A formal solution can be obtained using raytracing techniques adapted from geometrical optics. We reformulate inflationary perturbation theory in this language, and show that raytracing reproduces the familiar "delta N" Taylor expansion. Our method produces ordinary differential equations which allow the Taylor coefficients to be computed efficiently. We use raytracing methods to express the gauge transformation between field fluctuations and the curvature perturbation, zeta, in geometrical terms. Using these results we give a compact expression for the nonlinear gauge-transform part of fNL in terms of the principal curvatures of uniform energy-density hypersurfaces in field space.Comment: 22 pages, plus bibliography and appendix. v2: minor changes, matches version published in JCA

Dijet resonances, widths and all that

The search for heavy resonances in the dijet channel is part of the on-going physics programme, both at the Tevatron and at the LHC. Lower limits have been placed on the masses of dijet resonances predicted in a wide variety of models. However, across experiments, the search strategy assumes that the effect of the new particles is well-approximated by on-shell production and subsequent decay into a pair of jets. We examine the impact of off-shell effects on such searches, particularly for strongly interacting resonances.Comment: Version published in JHE

Immunological responses in human papillomavirus 16 E6/E7-transgenic mice to E7 protein correlate with the presence of skin disease

The human papillomavirus (HPV) oncogenes, E6 and E7, are believed to contribute to the development of cervical cancers in women infected with certain HPV genotypes, most notably HPV-16 and HPV-18. Given their expression in tumor tissue, E6 and E7 have been implicated as potential tumor-specific antigens. We have examined an HPV-16 E6- and E7-transgenic mouse lineage for immune responses to these viral oncoproteins. Mice in this lineage express the HPV-16 E6 and E7 genes in their skin and eyes, and on aging, these mice frequently develop squamous cell carcinomas and lenticular tumors. Young transgenic mice, which had measurable E7 protein in the eye but not in the skin, were immunologically naive to E7 protein. They mounted an immune response to E7 on immunization comparable to that of nontransgenic controls, suggesting a lack of immune tolerance to this protein. Older line 19 mice, which are susceptible to skin disease associated with transcription of the E6 and E7 open reading frames, had measurable E7 protein in their skin. These older transgenic mice spontaneously developed antibody responses to endogenous E7 protein, particularly in association with skin disease. Also detected in older mice were delayed-type hypersensitivity responses to E7. These finding parallel the humoral immune response to E7 protein in patients with HPV-associated cervical cancer and suggest that line 19 mice may provide a model for studying the immunobiology of HPV-associated cancers

A dynamical model for correlated two-pion-exchange in the pion-nucleon interaction

A microscopic model for the $N\bar N\to\pi\pi$ process is presented in the meson exchange framework, which in the pseudophysical region agrees with available quasiempirical information. The scalar ($\sigma$) and vector ($\rho$) piece of correlated two--pion exchange in the pion--nucleon interaction is then derived via dispersion integrals over the unitarity cut. Inherent ambiguities in the method and implications for the description of pion--nucleon scattering data are discussed.Comment: 20 pages, 11 postscript figure

Multi-field inflation with random potentials: field dimension, feature scale and non-Gaussianity

We explore the super-horizon evolution of the two-point and three-point correlation functions of the primordial density perturbation in randomly-generated multi-field potentials. We use the Transport method to evolve perturbations and give full evolutionary histories for observables. Identifying the separate universe assumption as being analogous to a geometrical description of light rays, we give an expression for the width of the bundle, thereby allowing us to monitor evolution towards the adiabatic limit, as well as providing a useful means of understanding the behaviour in $f_NL$. Finally, viewing our random potential as a toy model of inflation in the string landscape, we build distributions for observables by evolving trajectories for a large number of realisations of the potential and comment on the prospects for testing such models. We find the distributions for observables to be insensitive to the number of fields over the range 2 to 6, but that these distributions are highly sensitive to the scale of features in the potential. Most sensitive to the scale of features is the spectral index, with more than an order of magnitude increase in the dispersion of predictions over the range of feature scales investigated. Least sensitive was the non-Gaussianity parameter $f_NL$, which was consistently small; we found no examples of realisations whose non-Gaussianity is capable of being observed by any planned experiment.Comment: 22 pages, 9 figure

Local non-Gaussianity from rapidly varying sound speeds

We study the effect of non-trivial sound speeds on local-type non-Gaussianity during multiple-field inflation. To this end, we consider a model of multiple-field DBI and use the deltaN formalism to track the super-horizon evolution of perturbations. By adopting a sum separable Hubble parameter we derive analytic expressions for the relevant quantities in the two-field case, valid beyond slow variation. We find that non-trivial sound speeds can, in principle, curve the trajectory in such a way that significant local-type non-Gaussianity is produced. Deviations from slow variation, such as rapidly varying sound speeds, enhance this effect. To illustrate our results we consider two-field inflation in the tip regions of two warped throats and find large local-type non-Gaussianity produced towards the end of the inflationary process.Comment: 30 pages, 7 figures; typos corrected, references added, accepted for publication in JCA