Dirac neutrinos and anomaly-free discrete gauge symmetries

Relying on Dirac neutrinos allows an infinity of anomaly-free discrete gauge symmetries to be imposed on the Supersymmetric Standard Model, some of which are GUT-compatible.Comment: 24 pages, minor changes, existence of flipped discrete gauge symmetries is pointed ou

What is the Discrete Gauge Symmetry of the MSSM?

We systematically study the extension of the Supersymmetric Standard Model (SSM) by an anomaly-free discrete gauge symmetry Z_N. We extend the work of Ibanez and Ross with N=2,3 to arbitrary values of N. As new fundamental symmetries, we find four Z_6, nine Z_9 and nine Z_18. We then place three phenomenological demands upon the low-energy effective SSM: (i) the presence of the mu-term in the superpotential, (ii) baryon-number conservation upto dimension-five operators, and (iii) the presence of the see-saw neutrino mass term LHLH. We are then left with only two anomaly-free discrete gauge symmetries: baryon-triality, B_3, and a new Z_6, which we call proton-hexality, P_6. Unlike B_3, P_6 prohibits the dimension-four lepton-number violating operators. This we propose as the discrete gauge symmetry of the Minimal SSM, instead of R-parity.Comment: Typo in item 2 below Eq.(6.9) corrected (wrong factor of "3"); 27 pages, 5 table

Emerging technologies in microguidance and control

Employing recent advances in microfabrication, the Charles Stark Draper Laboratory has developed inertial guidance instruments of very small size and low cost. Microfabrication employs the batch processing techniques of solid state electronics, such as photolithography, diffusion, and etching, to carve mechanical parts. Within a few years, microfabricated gyroscopes should perform in the 10 to 100 deg/h range. Microfabricated accelerometers have demonstrated performance in the 50 to 500 microgravity range. These instruments will result in not only the redesign of conventional military products, but also new applications that could not exist without small, inexpensive sensors and computing. Draper's microfabricated accelerometers and gyroscopes will be described and test results summarized. Associated electronics and control issues will also be addressed. Gimballed, vibrating gyroscopes and force rebalance accelerometers constructed from bulk silicon, polysilicon surface-machined tuning fork gyroscopes, and quartz resonant accelerometers and gyroscopes are examined. Draper is pursuing several types of devices for the following reasons: to address wide ranges of performance, to realize construction in a flat pack, and to lessen the risks associated with emerging technologies

Cosmological perturbations of a perfect fluid and noncommutative variables

We describe the linear cosmological perturbations of a perfect fluid at the level of an action, providing thus an alternative to the standard approach based only on the equations of motion. This action is suited not only to perfect fluids with a barotropic equation of state, but also to those for which the pressure depends on two thermodynamical variables. By quantizing the system we find that (1) some perturbation fields exhibit a noncommutativity quite analogous to the one observed for a charged particle moving in a strong magnetic field, (2) local curvature and pressure perturbations cannot be measured simultaneously, (3) ghosts appear if the null energy condition is violated.Comment: 4 pages, uses RevTeX. Title modified, references and comments added

The role of urinary kininogen in the regulation of kinin generation

The role of urinary kininogen in the regulation of kinin generation. The kallikrein-kininogen-kinin system has been postulated to play a role in the regulation of blood pressure and modulation of renal salt and water transport. The activity of this system has usually been determined by measurements of urinary kallikrein excretion. However, urinary kallikrein rarely correlates with simultaneously measured urinary kinins. To further evaluate the factors influencing urinary kinin excretion, we evaluated the role of urinary kininogen in this system. Urines were analyzed from normal subjects and individuals with untreated essential hypertension and end-stage renal disease. Intact urinary kininogen was significantly correlated with urinary kinins in normal subjects (r = 0.65, P = 0.003) and essential hypertensives (r = 0.52, P = 0.026). In both essential hypertension and end-stage renal disease, urinary kinins were significantly decreased (8.00 ± 1.93, 0.90 ± 0.18, P < 0.05, respectively) compared to controls (23.73 ± 5.20). In essential hypertensives, the reduction in urinary kinins was paralleled by a reduction in intact kininogen with a normal excretion of kallikrein. In end-stage renal disease, the reduction in kinins was paralleled by a reduction in kallikrein with a normal excretion of intact kininogen. This data suggests that kininogen may be an important determinant of urinary kinin excretion in various disease states

Canonical Quantization of the Electromagnetic Field on the Kerr Background

We investigate the canonical quantization of the electromagnetic field on the Kerr background. We give new expressions for the expectation value of the electromagnetic stress-energy tensor in various vacua states and give a physical interpretation of the separate terms appearing in them. We numerically calculate the luminosity in these states. We also study the form of the renormalized stress-energy tensor close to the horizon when the electromagnetic field is in the past Boulware state.Comment: 27 zipped, postscript figure file

Current prospects and challenges for epilepsy gene therapy

This review addresses the state of gene therapy research for the treatment of epilepsy. Preclinical studies have demonstrated the anti-seizure efficacy of viral vector-based gene transfer through the use of a variety of strategies – from modulating classic neurotransmitter systems to targeting or overexpressing of neuropeptide receptors in seizure-specific brain regions. While these studies provide substantive proof of principle for viral vector gene therapy, future studies must address the challenges of vector immunity, cellular specificity and effective global delivery. As these issues are resolved, viral vector gene therapy should significantly impact the treatment of intractable epilepsy

Glycated AAV Vectors: Chemical Redirection of Viral Tissue Tropism

A chemical approach for selective masking of arginine residues on viral capsids, featuring an exogenous glycation reaction has been developed. Reaction of adeno-associated viral (AAV) capsids with the α-dicarbonyl compound, methylglyoxal resulted in formation of arginine adducts. Specifically, surface exposed guanidinium side chains were modified into charge neutral hydroimidazolones, thereby disrupting a continuous cluster of basic amino acid residues implicated in heparan sulfate binding. Consequent loss in heparin binding ability and decrease in infectivity were observed. Strikingly, glycated AAV retained ability to infect neurons in the mouse brain and were redirected from liver to skeletal and cardiac muscle following systemic administration in mice. Further, glycated AAV displayed altered antigenicity demonstrating potential for evading antibody neutralization. Generation of unnatural amino acid side chains through capsid glycation might serve as an orthogonal strategy to engineer AAV vectors displaying novel tissue tropisms for gene therapy applications

The Triple-Alpha Process and the Anthropically Allowed Values of the Weak Scale

In multiple-universe models, the constants of nature may have different values in different universes. Agrawal, Barr, Donoghue and Seckel have pointed out that the Higgs mass parameter, as the only dimensionful parameter of the standard model, is of particular interest. By considering a range of values of this parameter, they showed that the Higgs vacuum expectation value must have a magnitude less than 5.0 times its observed value, in order for complex elements, and thus life, to form. In this report, we look at the effects of the Higgs mass parameter on the triple-alpha process in stars. This process, which is greatly enhanced by a resonance in Carbon-12, is responsible for virtually all of the carbon production in the universe. We find that the Higgs vacuum expectation value must have a magnitude greater than 0.90 times its observed value in order for an appreciable amount of carbon to form, thus significantly narrowing the allowed region of Agrawal et al.Comment: 9 pages, 1 figur