Dijet rates with symmetric E_t cuts

We consider dijet production in the region where symmetric cuts on the transverse energy, $E_t$, are applied to the jets. In this region next-to--leading order calculations are unreliable and an all-order resummation of soft gluon effects is needed, which we carry out. Although, for illustrative purposes, we choose dijets produced in deep inelastic scattering, our general ideas apply additionally to dijets produced in photoproduction or $\gamma \gamma$ processes and should be relevant also to the study of prompt di-photon $E_t$ spectra in association with a recoiling jet, in hadron-hadron processesComment: 28 pages, 4 figure

PP-wave Black holes and The Matrix Model

We discuss the sizes of a black hole in the M theory pp-wave background, and how the transverse size can be reproduced in the matrix model.Comment: 12 pages, harvmac. v2: final version to be published in JHEP, refs. adde

Block-Spin Approach to Electron Correlations

We consider an expansion of the ground state wavefunction of quantum lattice many-body systems in a basis whose states are tensor products of block-spin wavefunctions. We demonstrate by applying the method to the antiferromagnetic spin-1/2 chain that by selecting the most important many-body states the technique affords a severe truncation of the Hilbert space while maintaining high accuracy.Comment: 17 pages, 3 Postscript figure

The resummation of inter-jet energy flow for gaps-between-jets processes at HERA

We calculate resummed perturbative predictions for gaps-between-jets processes and compare to HERA data. Our calculation of this non-global observable needs to include the effects of primary gluon emission (global logarithms) and secondary gluon emission (non-global logarithms) to be correct at the leading logarithm (LL) level. We include primary emission by calculating anomalous dimension matrices for the geometry of the specific event definitions and estimate the effect of non-global logarithms in the large $N_c$ limit. The resulting predictions for energy flow observables are consistent with experimental data.Comment: 31 pages, 4 figures, 2 table

Diffusion with rearranging traps

A model for diffusion on a cubic lattice with a random distribution of traps is developed. The traps are redistributed at certain time intervals. Such models are useful for describing systems showing dynamic disorder, such as ion-conducting polymers. In the present model the traps are infinite, unlike an earlier version with finite traps, this model has a percolation threshold. For the infinite trap version a simple analytical calculation is possible and the results agree qualitatively with simulation.Comment: Latex, five figure

Thermal Giant Graviton with Non-commutative Dipole Field

Using the type II near-extremal 3D-branes solution we apply the T-duality and smeared twist to construct the supergravity backgrounds which dual to the 4D finite temperature non-commutative dipole field theories. We first consider the zero-temperature system in which, depending on the property of dipole vectors it may be N=2, N=1 or N=0 theory. We investigate the rotating D3-brane configurations moving on the spactimes and show that, for the cases of N=2 and N =1 the rotating D3-brane could be blowed up to the stable spherical configuration which is called as giant graviton and has a less energy than the point-like graviton. The giant graviton configuration is stable only if its angular momentum was less than a critical value of $P_c$ which is an increasing function of the dipole strength. For the case of non-supersymmetric theory, however, the spherical configuration has a larger energy than the point-like graviton. We also find that the dipole field always render the dual giant graviton to be more stable than the point-like graviton. The relation of dual giant graviton energy with its angular momentum, which in the AdS/CFT correspondence being the operator anomalous dimension is obtained. We furthermore show that the temperature does not change the property of the giant graviton, while it will render the dual giant graviton to be unstable.Comment: Latex 20 pages, add comments about BPS bound below (3.8

Protein dynamics influence the enzymatic activity of phospholipase a/acyltransferases 3 and 4

Phospholipase A/acyltransferase 3 (PLAAT3) and PLAAT4 are enzymes involved in the synthesis of bioactive lipids. Despite sequential and structural similarities, the two enzymes differ in activity and specificity. The relation between the activity and dynamics of the N-terminal domains of PLAAT3 and PLAAT4 was studied. PLAAT3 has a much higher melting temperature and exhibits less nanosecond and millisecond dynamics in the active site, in particular in loop L2(B6), as shown by NMR spectroscopy and molecular dynamics calculations. Swapping the L2(B6) loops between the two PLAAT enzymes results in strongly increased phospholipase activity in PLAAT3 but no reduction in PLAAT4 activity, indicating that this loop contributes to the low activity of PLAAT3. The results show that, despite structural similarity, protein dynamics differ substantially between the PLAAT variants, which can help to explain the activity and specificity differences.Macromolecular BiochemistryMolecular Physiolog

New Supersymmetric String Compactifications

We describe a new class of supersymmetric string compactifications to 4d Minkowski space. These solutions involve type II strings propagating on (orientifolds of) non Calabi-Yau spaces in the presence of background NS and RR fluxes. The simplest examples have descriptions as cosets, generalizing the three-dimensional nilmanifold. They can also be thought of as twisted tori. We derive a formula for the (super)potential governing the light fields, which is generated by the fluxes and certain ``twists'' in the geometry. Detailed consideration of an example also gives strong evidence that in some cases, these exotic geometries are related by smooth transitions to standard Calabi-Yau or G2 compactifications of M-theory.Comment: 43 pages, harvmac bi

Comments on D-brane Interactions in PP-wave Backgrounds

We calculate the interaction potential between widely separated D-branes in PP-wave backgrounds in string theory as well as in low-energy supergravity. Timelike and spacelike orientations are qualitatively different but in both cases the effective brane tensions and RR charges take the same values as in Minkowski space in accordance with the expectations from the sigma model perturbation theory.Comment: Latex, 22 pages. Typos corrected and a reference added, final versio

Intimate partner violence in South Asian communities:Exploring the notion of 'shame' to promote understandings of migrant women's experiences

The notion of 'shame' is increasingly being recognized as a tool with some explanatory power to help promote understandings about a range of social problems. Through an exploration of migrant South Asian women's experiences of domestic violence and help-seeking practices, this article considers the relevance of the notion of shame as a unit of analysis to help contribute to the growing theoretical and empirical literature. This article sheds light on the meanings, events, processes and structures in the lives of migrant South Asian women respondents living in Hong Kong. Within the framework of the discussion on shame and intimate partner violence(IPV), the article also identifies the implications for social work practice