1,267 research outputs found

    General Criterion for the existence of Supertube and BIon in Curved Target Space

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    The supertube and BIon spike solutions are examined in a general curved target space. The criteria for the existence of these solutions are explicitly derived. Also the equation which the general BIon solution should satisfy is derived.Comment: 12 pages, no figur

    Supercurves

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    The TST-dual of the general 1/4-supersymmetric D2-brane supertube is identified as a 1/4-supersymmetric IIA `supercurve': a string with arbitrary transverse displacement travelling at the speed of light. A simple proof is given of the classical upper bound on the angular momentum, which is also recovered as the semi-classical limit of a quantum bound. The classical bound is saturated by a `superhelix', while the quantum bound is saturated by a bosonic oscillator state in a unique SO(8) representation.Comment: 1+14 pages, LaTe

    Supersymmetric Dyonic Black Holes in Kaluza-Klein Theory

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    We study supersymmetric, four-dimensional (4-d), Abelian charged black holes (BH's) arising in (4+n)-d (1 \le n \le 7) Kaluza-Klein (KK) theories. Such solutions, which satisfy supersymmetric Killing spinor equations (formally satisfied for any n) and saturate the corresponding Bogomol'nyi bounds, can be obtained if and only if the isometry group of the internal space is broken down to the U(1)_E \times U(1)_M gauge group; they correspond to dyonic BH's with electric Q and magnetic P charges associated with {\it different} U(1) factors. The internal metric of such configurations is diagonal with (n-2) internal radii constant, while the remaining two radii (associated with the respective electric and magnetic U(1) gauge fields) and the 4-d part of the metric turn out to be independent of n, i.e., solutions are effectively those of supersymmetric 4-d BH's of 6-d KK theory. For Q \ne 0 and P \ne 0, 4-d space-time has a null singularity, finite temperature (T_H \propto 1 / \sqrt{|QP|}) and zero entropy. Special cases with either Q=0 or P=0 correspond to the supersymmetric 4-d BH's of 5-d KK theory, first derived by Gibbons and Perry, which have a naked singularity and infinite temperature.Comment: 36 pages TEX (1 Postscript figure available via anonymous ftp to dept.physics.upenn.edu:/pub/UPR-623-T), UPR-623-

    Solitons on Branes

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    We examine the possibility that gauge field configurations on stacks of parallel Dp branes support topological solitons. We give an exhaustive list of possible soliton charges for p<7. We also discuss how configurations carrying the soliton charges can be constructed from intersecting branes.Comment: 15 pages, 2 figures; v2: two references added, version to be published in Nucl.Phys.

    Looking forward: Strategies for inclusivity

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    This final chapter draws together the ways in which intersectionality occurs for a range of stakeholders regarding constructions of gender in community colleges and provides tactics for increasing equity.https://scholarworks.wm.edu/educationbookchapters/1032/thumbnail.jp

    Gauge Theories with Tensors from Branes and Orientifolds

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    We present brane constructions in Type IIA string theory for N=1 supersymmetric SO and Sp gauge theories with tensor representations using an orientifold 6-plane. One limit of these set-ups corresponds to N=2 theories previously constructed by Landsteiner and Lopez, while a different limit yields N=1 SO or Sp theories with a massless tensor and no superpotential. For the Sp-type orientifold projection comparison with the field theory moduli space leads us to postulate two new rules governing the stability of configurations of D-branes intersecting the orientifold. Lifting one of our configurations to M-theory by finding the corresponding curves, we re-derive the N=1 dualities for SO and Sp groups using semi-infinite D4 branes.Comment: Discussion on duality in U(N) with a symmetric or antisymmetric flavor added to Section 4. Typos fixe

    Chronic allergen challenge induces bronchial mast cell accumulation in BALB/c but not C57BL/6 mice and is independent of IL-9

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    As genetically engineered mutant mice deficient in single genes are usually generated on a C57BL/6 background, to study mast cell trafficking in mutant mice, we initially investigated whether mast cells accumulated in bronchi in C57BL/6 mice challenged with OVA allergen acutely or chronically for 1 to 3 months. The total number of bronchial mast cells were quantitated using toluidine blue staining in airways of different sizes, i.e. , small (<90 µm), medium (90–155 µm), or large (>150 µm) airways. Non-OVA challenged and acute OVA challenged mice (C57BL/6 and BALB/c) had no detectable bronchial mast cells. Chronic OVA challenge in BALB/c mice for 1 or 3 months induced a significant increase in the number of bronchial mast cells in small-, medium-, and large-sized airways but minimal change in the number of bronchial mast cells in C57BL/6 mice. Both BALB/c and C57BL/6 mice developed significant lung eosinophilia following acute or chronic OVA challenge. Studies of IL-9-deficient mice on a BALB/c background demonstrated a significant increase in the number of bronchial mast cells in IL-9-deficient mice suggesting that IL-9 was not required for the bronchial accumulation of mast cells. Overall, these studies demonstrate that the chronic OVA challenge protocol we have utilized in BALB/c mice provides a model to study the mechanism of bronchial mast cell accumulation and that bronchial mast cell accumulation in chronic OVA challenged mice is independent of IL-9 in this model

    A Case of Infantile Alexander Disease Accompanied by Infantile Spasms Diagnosed by DNA Analysis

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    Alexander disease (AD) is a rare leukodystrophy of the central nervous system of unknown etiology. AD is characterized by progressive failure of central myelination and the accumulation of Rosenthal fibers in astrocytes, and is inevitably lethal in nature. Symptomatically, AD is associated with leukoencephalopathy with macrocephaly, seizures, and psychomotor retardation in infants, and usually leads to death within the first decade. Its characteristic magnetic resonance imaging (MRI) findings have been described as demyelination predominantly in the frontal lobe. Moreover, dominant mutations in the GFAP gene, coding for glial fibrillary acidic protein (GFAP), a principal astrocytic intermediate filament protein, have been shown to lead to AD. The disease can now be detected by genetic diagnosis. We report the Korean case of an 8-month-old male patient with AD. He was clinically characterized due to the presence of psychomotor retardation, megalencephaly, spasticity, and recurrent seizures including infantile spasms which is a remarkable presentation. Demyelination in the frontal lobe and in a portion of the temporal lobe was demonstrated by brain MRI. Moreover, DNA analysis of peripheral blood showed the presence of a R239L mutation in the GFAP gene, involving the replacement of guanine with thymine

    Gender Differences in the Effect of Obesity on Chronic Diseases among the Elderly Koreans

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    The objective of this study is to investigate gender differences of obesity on major chronic diseases in elderly Korean males and females. This study applied a cross sectional design using the 2005 Korean National Health and Nutrition Examination Survey (KNHNES). We selected 508 elderly males and 830 elderly females who were 60 or more years old. Obesity was defined using Body Mass Index (BMI) (≥ 25) or Waist Circumference (WC) (≥ 90 for men and ≥ 85 for women). We applied a surveylogistic regression to determine gender differences in relation to the effect of obesity on eleven major chronic diseases. Using WC, 46.2% of females were obese compared to 34.3% for males. Similarly, using BMI, 42.2% of females were obese compared to 31.7% for males. While obese males and females had similar profiles for developing metabolic syndrome components including hypertension, dyslipidemia, and diabetes (odds ratios [ORs] were 1.8-2.6 for males and 1.7-2.5 for females), obese elderly females had additional risks for arthritis and urinary incontinence (ORs 1.5-1.8 for females) as well as higher prevalence for these diseases. A clearer understanding of gender differences in relation to the association between obesity and chronic diseases would be helpful for reducing the social burden of chronic diseases in the elderly
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