87 research outputs found
Wormholes and Flux Tubes in 5D Kaluza-Klein Theory
In this paper spherically symmetric solutions to 5D Kaluza-Klein theory, with
``electric'' and/or ``magnetic'' fields are investigated. It is shown that the
global structure of the spacetime depends on the relation between the
``electrical'' and ``magnetic'' Kaluza-Klein fields. For small ``magnetic''
field we find a wormhole-like solution. As the strength of the ``magnetic''
field is increased relative to the strength of the ``electrical'' field, the
wormhole-like solution evolves into a finite or infinite flux tube depending on
the strengths of the two fields. For the large ``electric'' field case we
conjecture that this solution can be considered as the mouth of a wormhole,
with the , and components of the metric acting as
the source of the exotic matter necessary for the formation of the wormhole's
mouth. For the large ``magnetic'' field case a 5D flux tube forms, which is
similar to the flux tube between two monopoles in Type-II superconductors, or
the hypothesized color field flux tube between two quarks in the QCD vacuum.Comment: 12 pages, 5 eps.figures, REVTEX, Discussion about null surfaces
ammended. References added. To be published in PR
Stabilization of internal spaces in multidimensional cosmology
Effective 4-dimensional theories are investigated which were obtained under
dimensional reduction of multidimensional cosmological models with a minimal
coupled scalar field as matter source. Conditions for the internal space
stabilization are considered and the possibility for inflation in the external
space is discussed. The electroweak as well as the Planck fundamental scale
approaches are investigated and compared with each other. It is shown that
there exists a rescaling for the effective cosmological constant as well as for
gravitational exciton masses in the different approaches.Comment: 12 pages, LaTeX2e, to appear in Phys.Rev.D, note adde
Nonlinear multidimensional cosmological models with form fields: stabilization of extra dimensions and the cosmological constant problem
We consider multidimensional gravitational models with a nonlinear scalar
curvature term and form fields in the action functional. In our scenario it is
assumed that the higher dimensional spacetime undergoes a spontaneous
compactification to a warped product manifold. Particular attention is paid to
models with quadratic scalar curvature terms and a Freund-Rubin-like ansatz for
solitonic form fields. It is shown that for certain parameter ranges the extra
dimensions are stabilized. In particular, stabilization is possible for any
sign of the internal space curvature, the bulk cosmological constant and of the
effective four-dimensional cosmological constant. Moreover, the effective
cosmological constant can satisfy the observable limit on the dark energy
density. Finally, we discuss the restrictions on the parameters of the
considered nonlinear models and how they follow from the connection between the
D-dimensional and the four-dimensional fundamental mass scales.Comment: 21 pages, LaTeX2e, minor changes, improved references, fonts include
Annexin A1 expression in a pooled breast cancer series: Association with tumor subtypes and prognosis
Background: Annexin A1 (ANXA1) is a protein related with the carcinogenesis process and metastasis formation in many tumors. However, little is known about the prognostic value of ANXA1 in breast cancer. The purpose of this study is to evaluate the association between ANXA1 expression, BRCA1/2 germline carriership, specific tumor subtypes and survival in breast cancer patients. Methods: Clinical-pathological information and follow-up data were collected from nine breast cancer studies from the Breast Cancer Association Consortium (BCAC) (n = 5,752) and from one study of familial breast cancer patients with BRCA1/2 mutations (n = 107). ANXA1 expression was scored based on the percentage of immunohistochemical staining in tumor cells. Survival analyses were performed using a multivariable Cox model. Results: The frequency of ANXA1 positive tumors was higher in familial breast cancer patients with BRCA1/2 mutations than in BCAC patients, with 48.6 % versus 12.4 %, respectively; P adj = 1.35; 95 % CI = 1.05-1.73), but the association weakened after 10 years (HRadj = 1.13; 95 % CI = 0.91-1.40). ANXA1 was a significant independent predictor of survival in HER2+ patients (10-years BCSS: HRadj = 1.70; 95 % CI = 1.17-2.45). Conclusions: ANXA1 is overexpressed in familial breast cancer patients with BRCA1/2 mutations and correlated with poor prognosis features: triple negative and poorly differentiated tumors. ANXA1 might be a biomarker candidate for breast cancer survival prediction in high risk groups such as HER2+ cases
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Track A Basic Science
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd
Managing highly flexible facilities: an essential complementary asset at risk
Purpose: Twenty first century problems are increasingly being addressed by multi technology solutions developed by regional entrepreneurial and intreprepreneurial innovators. However, they require an expensive new type of fabrication facility. Multiple technology production facilities (MTPF) have become the essential incubators for these innovations. This paper aims to focus on the issues. Design/methodology/approach: The authors address the lack of managerial understanding of how to express the value and operationally manage MTPF centers through the use of investigative case study methods for multiple firms in the study. Findings: Owing to the MTPF centers' novelty and outward similarity to high volume semiconductor fabrication (HVF) facilities, they are laden with ineffective operation and strategic management practices. Metrics are the standard for both operational and strategic management of HVF facilities, yet their application to this new type of center is proving ineffectual. Research limitations/implications: These new types of regional economic resources may be at risk. A new approach is needed. Practical implications: The authors develop an operational and strategic metrics management approach for MTPFs that are based on these facilities' unique nature and leverages both the HVF and R&D metrics knowledge base. Social implications: Innovations at the interface of micro technology, nanotechnology and semiconductor micro fabrication are poised to solve many of these problems and become a basis for job creation and prosperity. If a new management technique is not developed, then these harbingers of regional economic development will be closed. Originality/value: While there is an abundance of research on metrics for HVF, this is the first attempt to develop metrics for MTPF
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