Gravitational form factors and transverse spin sum rule in a light front quark-diquark model in AdS/QCD

The gravitational form factors are related to the matrix elements of the energy-momentum tensor $T^{\mu\nu}$. Using the light front wave functions of the scalar quark-diquark model for nucleon predicted by the soft-wall AdS/QCD, we calculate the flavor dependent $A(Q^2)$, $B(Q^2)$ and $\bar{C}(Q^2)$ form factors. We also present all the matrix element of the energy-momentum tensor in a transversely polarized state. Further, we evaluate the matrix element of Pauli-Lubanski operator in this model and show that the intrinsic spin sum rule involves the form factor $\bar{C}$. The longitudinal momentum densities in the transverse impact parameter space are also discussed for both unpolarized and transversely polarized nucleons.Comment: 28 pages, 7 figure

Sivers and cos⁡2ϕ\cos 2\phi Asymmetries in Semi-inclusive Deep Inelastic Scattering in Light-front Holographic Model

The spin asymmetries in SIDIS associated with $T$-odd TMDs are presented in a light-front quark-diquark model of a proton. To incorporate the effects of the final state interaction, the light front wave functions are modified to have a phase factor which is essential to have Sivers or Boer-Mulders functions. The Sivers and Boer-Mulder asymmetries are compared with HERMES and COMPASS data.Comment: 24 pages, 09 figure

Fast-Track Abdominal Aortic Aneurysm Repair

The open repair of abdominal aortic aneurysm (AAA) continues to evolve with incorporation of less invasive methods for surgical exposure and the use of patient care pathways for shorter hospital stays. In a consecutive series of 30 patients with infrarenal AAA, a fast-track hospital care pathway was implemented that included the following: AAA exposure via a limited (10-15 cm) retroperitoneal incision, use of self-retaining retractor and special vascular clamps/instruments, and prosthetic graft endoaneurysmorrhaphy. Excellent anatomic exposure for graft implantation was achieved with an average operative time of 175 minutes. Use of oral metoclopromide and patient-controlled epidural analgesia resulted in patient ambulation and oral diet on postoperative day 1. Average length of hospital stay was 3.6 days (range: 3-7 days), and no patient required readmission for AAA repair-related or gastrointestinal problems. One patient died (30-day mortality rate of 3.3%) caused by delayed recognition of a splenic injury, and 1 patient sustained an intraoperative ureter injury that was repaired and stented. Although stent-graft exclusion for AAA repair has become popular, the major advantages of endovascular therapy, such as shorter ICU and hospital stays, earlier dietary feeding, and reduction in postoperative morbidity, can also be achieved by using minimal incision exposure for AAA interposition grafting combined with traditional hand-sewn vascular anastomoses. Fast-track AAA repair is applicable to the majority of patients with infrarenal AAAs, and vascular surgeons can easily master the technique of limited incision retroperitoneal exposure. This approach avoids the concerns of endovascular stent-graft durability and the mandatory vascular imaging follow-up to identify endoleak development and AAA enlargement

Evaluation of the role of sigma B in Mycobacterium smegmatis

The alternate sigma factor, sigB, is known to play a crucial role in maintaining the stationary phase in mycobacteria. In this communication, we have studied the proteomics of Mycobacterium smegmatis mc2155 and its two derivatives, one of which has a disrupted sigB gene and the other, PMVSigB, which contains a multicopy plasmid containing sigB. We have identified by two-dimensional gel analyses, several proteins that are over-expressed in PMVSigB compared to mc2155. These proteins are either stress proteins or participate actively in different metabolic pathways of the organisms. On the other hand, when sigB deleted mycobacteria were grown until the stationary phase and its two-dimensional protein profile was compared to that of mc2155, few DNA binding proteins were found to be up-regulated. We have shown recently that upon over-expressing sigB, the cell surface glycopeptidolipids of M. smegmatis are hyperglycosylated, a situation similar to what was observed for nutritionally starved bacteria. Gene expression profile through quantitative PCR presented here identified a Rhamnosyltransferase responsible for this hyperglycosylation

A Numerical Experiment in DLCQ: Microcausality, Continuum Limit and all that

Issues related with microcausality violation and continuum limit in the context of (1+1) dimensional scalar field theory in discretized light-cone quantization (DLCQ) are addressed in parallel with discretized equal time quantization (DETQ) and the fact that Lorentz invariance and microcausality are restored if one can take the continuum limit properly is emphasized. In the free case, it is shown with numerical evidence that the continuum results can be reproduced from DLCQ results for the Pauli-Jordan function and the real part of Feynman propagator. The contributions coming from $k^+$ near zero region in these cases are found to be very small in contrast to the common belief that $k^+=0$ is an accumulation point. In the interacting case, aspects related to the continuum limit of DLCQ results in perturbation theory are discussed.Comment: Minor changes in the text, accepted for publication in Phys. Letts.