From the type I string to M-theory: A continuous connection

Abstract By fibering the duality between the E8 × E8 heterotic string on T3 and M-theory on K3, we study heterotic duals of M-theory compactified on G2 orbifolds of the form T7/$$ {\mathbb{Z}}_2^3 $$ ℤ 2 3 . While the heterotic compactification space is straightforward, the description of the gauge bundle is subtle, involving the physics of point-like instantons on orbifold singularities. By comparing the gauge groups of the dual theories, we deduce behavior of a “half-G2” limit, which is the M-theory analog of the stable degeneration limit of F-theory. The heterotic backgrounds exhibit point-like instantons that are localized on pairs of orbifold loci, similar to the “gauge-locking” phenomenon seen in Hořava-Witten compactifications. In this way, the geometry of the G2 orbifold is translated to bundle data in the heterotic background. While the instanton configuration looks surprising from the perspective of the E8 × E8 heterotic string, it may be understood as T-dual Spin(32)/ℤ2 instantons along with winding shifts originating in a dual Type I compactification.

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Theory and phenomenology of type I strings and M-theory

Classical and Quantum Gravity ◽

10.1088/0264-9381/17/22/201 ◽

2000 ◽

Vol 17 (22) ◽

pp. R41-R116 ◽

Cited By ~ 86

Author(s):

Emilian Dudas

Keyword(s):

Type I ◽

M Theory

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The type I D-instanton and its M-theory origin

Journal of High Energy Physics ◽

10.1088/1126-6708/2000/08/004 ◽

2000 ◽

Vol 2000 (08) ◽

pp. 004-004 ◽

Cited By ~ 3

Author(s):

Tathagata Dasgupta ◽

Matthias R Gaberdiel ◽

Michael B Green

Keyword(s):

Type I ◽

M Theory

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ORBIFOLDS OF M-THEORY AND STRING THEORY

Modern Physics Letters A ◽

10.1142/s021773239600134x ◽

1996 ◽

Vol 11 (16) ◽

pp. 1339-1347 ◽

Cited By ~ 28

Author(s):

ASHOKE SEN

Keyword(s):

String Theory ◽

Type I ◽

Twisted Sector ◽

Duality Transformation ◽

M Theory

It is shown that many of the conjectured dualities involving orbifold compactification of M-theory follow from the known dualities involving M-theory and string theory in 10 dimensions, and the ansatz that orbifolding procedure commutes with the duality transformation. This ansatz also leads to a new duality conjecture, namely that M-theory compactified on T8/Z2 is dual to type I string theory on T7. In this case the “twisted sector states” in M-theory live on 16 membranes transverse to the internal manifold.

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Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067522 ◽

1970 ◽

Vol 28 ◽

pp. 106-107 ◽

Cited By ~ 1

Author(s):

Ronald S. Weinstein ◽

N. Scott McNutt

Keyword(s):

New Zealand ◽

General Hospital ◽

Massachusetts General Hospital ◽

Type I ◽

Type Ii ◽

Collaborative Effort ◽

Temperature And Pressure ◽

The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

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Two Distinct Types of Microfilaments in the Cytoplasm of Human Adenohypophysial Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073787 ◽

1973 ◽

Vol 31 ◽

pp. 668-669

Author(s):

E. Horvath ◽

K. Kovacs ◽

I. E. Stratmann ◽

C. Ezrin

Keyword(s):

Pituitary Tumors ◽

Average Diameter ◽

Anterior Lobe ◽

Uranyl Acetate ◽

Type I ◽

Breast Cancer Patients ◽

Human Pituitary ◽

Severe Diabetes ◽

Pituitary Glands ◽

Membrane Bound

Surgically removed human pituitary glands as well as pituitary tumors fixed in glutaraldehyde, postfixed in osmium tetroxide, embedded in epon resin, stained with uranyl acetate and lead citrate have been investigated by electron microscopy in order to correlate ultrastructure with functional activity. In the course of this study two distinct types of microfilaments have been identified in the cytoplasm of adenohypophysiocytes.Type I microfilaments (Fig. 1) were found in the cytoplasm of anterior lobe cells of five female subjects with disseminated mammary cancer and two patients with severe diabetes mellitus. The breast cancer patients were treated pre-operatively for various periods of time with different doses of oxysteroids. The microfilaments had an average diameter of JO A, formed parallel bundles, were scattered irregularly in the cytoplasm and were frequently located in the perikaryon. They were not membrane-bound and failed to show any periodicity.

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The diagnosis of metabolic storage disease in skin biopsies (a light-, electronmicroscopic, and analytical study)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084119 ◽

1978 ◽

Vol 36 (2) ◽

pp. 648-649

Author(s):

W. Jurecka ◽

W. Gebhart ◽

H. Lassmann

Keyword(s):

Storage Disease ◽

Hunter Syndrome ◽

Histochemical Demonstration ◽

Sweat Glands ◽

Type I ◽

Storage Material ◽

Scheie Syndrome ◽

Storage Products ◽

Skin Biopsies ◽

Type V

Diagnosis of metabolic storage disease can be established by the determination of enzymes or storage material in blood, urine, or several tissues or by clinical parameters. Identification of the accumulated storage products is possible by biochemical analysis of isolated material, by histochemical demonstration in sections, or by ultrastructural demonstration of typical inclusion bodies. In order to determine the significance of such inclusions in human skin biopsies several types of metabolic storage disease were investigated. The following results were obtained.In MPS type I (Pfaundler-Hurler-Syndrome), type II (Hunter-Syndrome), and type V (Ullrich-Scheie-Syndrome) mainly “empty” vacuoles were found in skin fibroblasts, in Schwann cells, keratinocytes and macrophages (Dorfmann and Matalon 1972). In addition, prominent vacuolisation was found in eccrine sweat glands. The storage material could be preserved in part by fixation with cetylpyridiniumchloride and was also present within fibroblasts grown in tissue culture.

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