M-theory, the signature theorem, and geometric invariants

The equations of motion and the Bianchi identity of the C-field in M-theory are encoded in terms of the signature operator. We then reformulate the topological part of the action in M-theory using the signature, which leads to connections to the geometry of the underlying manifold, including positive scalar curvature. This results in a variation on the miraculous cancellation formula of Alvarez-Gaum\'e and Witten in twelve dimensions and leads naturally to the Kreck-Stolz s-invariant in eleven dimensions. Hence M-theory detects diffeomorphism type of eleven-dimensional (and seven-dimensional) manifolds, and in the restriction to parallelizable manifolds classifies topological eleven-spheres. Furthermore, requiring the phase of the partition function to be anomaly-free imposes restrictions on allowed values of the s-invariant. Relating to string theory in ten dimensions amounts to viewing the bounding theory as a disk bundle, for which we study the corresponding phase in this formulation.Comment: 17 page

Quantum discontinuity between zero and infinitesimal graviton mass with a Lambda term

We show that the recently demonstrated absence of the usual discontinuity for massive spin 2 with a Lambda term is an artifact of the tree approximation, and that the discontinuity reappears at one loop.Comment: 8 pages, revtex 3.1, title changed (version to appear in Phys. Rev. Lett.

The Elliptic curves in gauge theory, string theory, and cohomology

Elliptic curves play a natural and important role in elliptic cohomology. In earlier work with I. Kriz, thes elliptic curves were interpreted physically in two ways: as corresponding to the intersection of M2 and M5 in the context of (the reduction of M-theory to) type IIA and as the elliptic fiber leading to F-theory for type IIB. In this paper we elaborate on the physical setting for various generalized cohomology theories, including elliptic cohomology, and we note that the above two seemingly unrelated descriptions can be unified using Sen's picture of the orientifold limit of F-theory compactification on K3, which unifies the Seiberg-Witten curve with the F-theory curve, and through which we naturally explain the constancy of the modulus that emerges from elliptic cohomology. This also clarifies the orbifolding performed in the previous work and justifies the appearance of the w_4 condition in the elliptic refinement of the mod 2 part of the partition function. We comment on the cohomology theory needed for the case when the modular parameter varies in the base of the elliptic fibration.Comment: 23 pages, typos corrected, minor clarification

Pattern of Presentation of Coronary Artery Disease in Hypertensive Patients

Background: Hypertension is a major risk factor for coronary artery disease (CAD) and left ventricular hypertrophy (LVH). Hypertensives have a threefold increase in cardiac death (due to either CAD or to cardiac failure).In Sudan hypertension complications were increasing in incidence and prevalence. Evaluating chest pain in hypertensive patients presents challenges because of left ventricular hypertrophy as a cause of chest pain besides CAD. There are limited data on different aspects of hypertensioncomplications.Objectives: To assess the CAD as a cause of chest pain, to see the pattern and severity of CAD and to find the correlation between ECG, ECHO and coronary angiography findings in hypertensive patientsMethodology: 135 known hypertensive patients presented with chest pain were assessed through ECG, ECHO and coronary angiography.Results: The participants’ ages ranged between 39 and 90 years, with mean age of 59 years .73.3% of them were found to have CAD. The left anterior descending (LAD) artery was the most involved one. Left main (LM) artery was the least involved. Electrocardiography (ECG) showed that LVH is found in more than 50%of patients with CAD. BMI was >25 in 41.5%. Percutaneous coronary intervention (PCI) was recommended in (31.4%), coronary artery bypass graft (CABG) in(21.6%). 33% and 25% of these consecutively have hypertension for 10 years or more.Conclusion: CAD is the main cause of chest pain in hypertensives. Aging, body mass index, duration and magnitude of hypertension and LVH have strong and frequent association with CAD

Magnetic Anisotropy of Co2+ as Signature of Intrinsic Ferromagnetism in ZnO:Co

We report on the magnetic properties of thoroughly characterized Zn1-xCoxO epitaxial thin films, with low Co concentration, x=0.003-0.005. Magnetic and EPR measurements, combined with crystal field theory, reveal that isolated Co2+ ions in ZnO possess a strong single ion anisotropy which leads to an "easy plane" ferromagnetic state when the ferromagnetic Co-Co interaction is considered. We suggest that the peculiarities of the magnetization process of this state can be viewed as a signature of intrinsic ferromagnetism in ZnO:Co materials.Comment: 4 pages, 4 figure

LIPID PEROXIDE LEVELS AND ANTIOXIDANT STATUS IN HEALTHY AND ALCOHOLIC HEPATITIS PATIENTS

Background: Alcohol remains the single most significant cause of liver disease throughout the Western world, responsible for between 40 and 80% of cases of cirrhosis in different countries. Material & Methods:The study was conducted in Department of Biochemistry, Santosh medical college & Hospital, Ghaziabad and Veer Chandra Singh Garhwali Govt. Institute of Medical Sciences & Research, 164 alcoholic hepatitis patients were subjected to detailed clinical examination and laboratory investigations and the results were compared with 82controls. Blood samples were collected for oxidative stress parameters. It was observed that there was a significant increase in activities of Catalase, SOD, MDA, GPX and GR activity in patients with alcoholic hepatitis when compared to controls. Results: Results of our study show higher oxygen free radical production, evidenced by elevated levels of MDA and decreased levels of Catalase, SOD, GPx, GR, and TAS activity, supporting the evidence of oxidative stress in alcoholic hepatitis patients. Decreased concentrations of antioxidant support the hypothesis that alcoholic hepatitis is an important causative factor in pathogenesis of lipid peroxidation. Conclusion: Theantioxidant defense mechanisms might be impaired in patients with alcoholic hepatitis. These findings also provide a theoretical basis for development of novel therapeutic strategies, such as antioxidant supplementation. Keywords: Alcoholic Hepatitis; Catalase; Glutathione Peroxidase; Glutathione Reductase; Malondialdehyde; Superoxide dismutase; Total antioxidant status

Principal infinity-bundles - General theory

The theory of principal bundles makes sense in any infinity-topos, such as that of topological, of smooth, or of otherwise geometric infinity-groupoids/infinity-stacks, and more generally in slices of these. It provides a natural geometric model for structured higher nonabelian cohomology and controls general fiber bundles in terms of associated bundles. For suitable choices of structure infinity-group G these G-principal infinity-bundles reproduce the theories of ordinary principal bundles, of bundle gerbes/principal 2-bundles and of bundle 2-gerbes and generalize these to their further higher and equivariant analogs. The induced associated infinity-bundles subsume the notions of gerbes and higher gerbes in the literature. We discuss here this general theory of principal infinity-bundles, intimately related to the axioms of Giraud, Toen-Vezzosi, Rezk and Lurie that characterize infinity-toposes. We show a natural equivalence between principal infinity-bundles and intrinsic nonabelian cocycles, implying the classification of principal infinity-bundles by nonabelian sheaf hyper-cohomology. We observe that the theory of geometric fiber infinity-bundles associated to principal infinity-bundles subsumes a theory of infinity-gerbes and of twisted infinity-bundles, with twists deriving from local coefficient infinity-bundles, which we define, relate to extensions of principal infinity-bundles and show to be classified by a corresponding notion of twisted cohomology, identified with the cohomology of a corresponding slice infinity-topos. In a companion article [NSSb] we discuss explicit presentations of this theory in categories of simplicial (pre)sheaves by hyper-Cech cohomology and by simplicial weakly-principal bundles; and in [NSSc] we discuss various examples and applications of the theory.Comment: 46 pages, published versio

LIPID PEROXIDE LEVELS AND ANTIOXIDANT STATUS IN HEALTHY AND ALCOHOLIC HEPATITIS PATIENTS

Background: Alcohol remains the single most significant cause of liver disease throughout the Western world, responsible for between 40 and 80% of cases of cirrhosis in different countries. Material & Methods:The study was conducted in Department of Biochemistry, Santosh medical college & Hospital, Ghaziabad and Veer Chandra Singh Garhwali Govt. Institute of Medical Sciences & Research, 164 alcoholic hepatitis patients were subjected to detailed clinical examination and laboratory investigations and the results were compared with 82controls. Blood samples were collected for oxidative stress parameters. It was observed that there was a significant increase in activities of Catalase, SOD, MDA, GPX and GR activity in patients with alcoholic hepatitis when compared to controls. Results: Results of our study show higher oxygen free radical production, evidenced by elevated levels of MDA and decreased levels of Catalase, SOD, GPx, GR, and TAS activity, supporting the evidence of oxidative stress in alcoholic hepatitis patients. Decreased concentrations of antioxidant support the hypothesis that alcoholic hepatitis is an important causative factor in pathogenesis of lipid peroxidation. Conclusion: Theantioxidant defense mechanisms might be impaired in patients with alcoholic hepatitis. These findings also provide a theoretical basis for development of novel therapeutic strategies, such as antioxidant supplementation. Keywords: Alcoholic Hepatitis; Catalase; Glutathione Peroxidase; Glutathione Reductase; Malondialdehyde; Superoxide dismutase; Total antioxidant status

Hypermatrix factors for string and membrane junctions

The adjoint representations of the Lie algebras of the classical groups SU(n), SO(n), and Sp(n) are, respectively, tensor, antisymmetric, and symmetric products of two vector spaces, and hence are matrix representations. We consider the analogous products of three vector spaces and study when they appear as summands in Lie algebra decompositions. The Z3-grading of the exceptional Lie algebras provide such summands and provides representations of classical groups on hypermatrices. The main natural application is a formal study of three-junctions of strings and membranes. Generalizations are also considered.Comment: 25 pages, 4 figures, presentation improved, minor correction

ZnO:Co Diluted Magnetic Semiconductor or Hybrid Nanostructure for Spintronics?

We have studied the influence of intrinsic and extrinsic defects in the magnetic and electrical transport properties of Co-doped ZnO thin films. X ray absorption measurements show that Co substitute Zn in the ZnO structure and it is in the 2+ oxidation state. Magnetization (M) measurements show that doped samples are mainly paramagnetic. From M vs. H loops measured at 5 K we found that the values of the orbital L and spin S numbers are between 1 and 1.3 for L and S = 3/2, in agreement with the representative values for isolated Co 2+. The obtained negative values of the Curie-Weiss temperatures indicate the existence of antiferromagnetic interactions between transition metal atoms.Comment: To be published in Journal of Materials Scienc