Obstructions to embeddability into hyperquadrics and explicit examples

We give series of explicit examples of Levi-nondegenerate real-analytic hypersurfaces in complex spaces that are not transversally holomorphically embeddable into hyperquadrics of any dimension. For this, we construct invariants attached to a given hypersurface that serve as obstructions to embeddability. We further study the embeddability problem for real-analytic submanifolds of higher codimension and answer a question by Forstneri\v{c}.Comment: Revised version, appendix and references adde

Properties of a beam splitter entangler with Gaussian input states

An explicit formula is given for the quantity of entanglement in the output state of a beam splitter, given the squeezed vacuum states input in each mode.Comment: To appear in Phys. Rev.

Improved effective mobility extraction in MOSFETs

The standard method of extracting carrier effective mobility from electrical measurements on MOSFETs is reviewed and the assumptions implicit in this method are discussed. A novel technique is suggested that corrects for the difference in drain bias during IV and CV measurements. It is further shown that the lateral field and diffusion corrections, which are both commonly neglected, in fact cancel. The effectiveness of the proposed technique is demonstrated by application to data measured on a quasi-planar SOI finFET at 300 K and 4 K

Symmetry Constraints and the Electronic Structures of a Quantum Dot with Thirteen Electrons

The symmetry constraints imposing on the quantum states of a dot with 13 electrons has been investigated. Based on this study, the favorable structures (FSs) of each state has been identified. Numerical calculations have been performed to inspect the role played by the FSs. It was found that, if a first-state has a remarkably competitive FS, this FS would be pursued and the state would be crystal-like and have a specific core-ring structure associated with the FS. The magic numbers are found to be closely related to the FSs.Comment: 13 pages, 5 figure

Supersymmetric CP Violation in B→Xsl+l−B \to X_s l^+ l^- in Minimal Supergravity Model

Direct CP asymmetries and the CP violating normal polarization of lepton in inclusive decay B \to X_s l^+ l^- are investigated in minimal supergravity model with CP violating phases. The contributions coming from exchanging neutral Higgs bosons are included. It is shown that the direct CP violation in branching ratio, A_{CP}^1, is of {\cal{O}}(10^{-3}) for l=e, \mu, \tau. The CP violating normal polarization for l=\mu can reach 0.5 percent when tan\beta is large (say, 36). For l=\tau and in the case of large \tan\beta, the direct CP violation in backward-forward asymmetry, A_{CP}^2, can reach one percent, the normal polarization of \tau can be as large as a few percent, and both are sensitive to the two CP violating phases, \phi_\mu and \phi_{A_0}, and consequently it could be possible to observe them (in particular, the normal polarization of \tau) in the future B factories.Comment: 14 pages, latex, 5 figure

Alcohol Exposure Induces Nucleolar Stress and Apoptosis in Mouse Neural Stem Cells and Late-Term Fetal Brain

Prenatal alcohol exposure (PAE) is a leading cause of neurodevelopmental disability through its induction of neuronal growth dysfunction through incompletely understood mechanisms. Ribosome biogenesis regulates cell cycle progression through p53 and the nucleolar cell stress response. Whether those processes are targeted by alcohol is unknown. Pregnant C57BL/6J mice received 3 g alcohol/kg daily at E8.5–E17.5. Transcriptome sequencing was performed on the E17.5 fetal cortex. Additionally, primary neural stem cells (NSCs) were isolated from the E14.5 cerebral cortex and exposed to alcohol to evaluate nucleolar stress and p53/MDM2 signaling. Alcohol suppressed KEGG pathways involving ribosome biogenesis (rRNA synthesis/processing and ribosomal proteins) and genes that are mechanistic in ribosomopathies (Polr1d, Rpl11; Rpl35; Nhp2); this was accompanied by nucleolar dissolution and p53 stabilization. In primary NSCs, alcohol reduced rRNA synthesis, caused nucleolar loss, suppressed proliferation, stabilized nuclear p53, and caused apoptosis that was prevented by dominant-negative p53 and MDM2 overexpression. Alcohol’s actions were dose-dependent and rapid, and rRNA synthesis was suppressed between 30 and 60 min following alcohol exposure. The alcohol-mediated deficits in ribosomal protein expression were correlated with fetal brain weight reductions. This is the first report describing that pharmacologically relevant alcohol levels suppress ribosome biogenesis, induce nucleolar stress in neuronal populations, and involve the ribosomal/MDM2/p53 pathway to cause growth arrest and apoptosis. This represents a novel mechanism of alcohol-mediated neuronal damage

Re-envisioning the pedestrian interface

Thesis (S.M. in Architecture Studies)--Massachusetts Institute of Technology, Dept. of Architecture, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 89-91).The thesis begins with an interest in the diversity and ambiguity of open spaces in a consumption oriented society: Hong Kong. The hustle and bustle of informal markets, together with the traditional pedestrian streets that ow from the mountains down to the waterfront are typical examples of such open spaces. However, these multifunctional spaces are being eliminated now, with the domination of megamalls. This phenomenon gives rise to a conflict between the usurpation of open space by commercialism and citizens' needs for daily use of it. The thesis aims to reintegrate the original diversity and ambiguity into current open spaces of Hong Kong. The author addressed this problem by researching the contemporary and historical making and use of open spaces within the evolution of Hong Kong's economic structure. By diagraming a spectrum of shopping spaces with such characteristics, the thesis proposes an interior urbanism, an alternative pedestrian interface, that not only extends the commercial core to its waterfront, but also provides a new playground for dynamic civic life. As an architectural device, the interface facilitates the movement of people from a subway station to a ferry terminal. Within this process, the interface creates "moments" with a juxtaposition of four types of commercial programs- informal markets, street retail stores, mall stores, and luxury flagships- and a view of the harbor. In such moments, both locals and tourists have an unique city experience that belongs only to Hong Kong.by Peng Huang.S.M.in Architecture Studie

Financial impacts of and financing methods for high-speed rail in Portugal

Thesis (S.M. in Transportation)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 178-188).High-speed rail (HSR) becomes a very hot topic recently when all Portugal, the United Stated, China, Japan, Spain, etc. are ambitious in building their HSR systems. Although HSR is expected to shrink the temporal distance between cities, reshape the travel patterns of people toward environment friendly ones, create an image effect for the country building it, promote regional economics, etc., HSR is more capital intensive than other transportation projects in both unit cost (the cost per lane km) and total cost. Due to its high costs and public or private budget constraints, HSR may have significant financial impacts on other transportation investments. And it is important to lower the costs of HSR building and explore more funding opportunities to make HSR investments more financially viable. This research aims to understand the financial impacts of HSR investments and to explore financing methods for them. Firstly, this research examines the crowding out effect of HSR investments on other transportation investments-whether financing HSR makes the funds for other transportation projects less available due to public or private budget constraints. In addition, this research compares HSR financing with the financing of other transportation projects to figure out the uniqueness of HSR financing. Finally, this research explores innovative financing methods and identifies megaregion revenues to make HSR investments more financially viable. We find that HSR investments crowd out other transportation investments based on the worldwide experience. In the end, we propose the use of monoline wrapped bonds and the establishment of Portuguese infrastructure bank to lower the financial costs of Portuguese HSR investments. And we recommend the use of value capture mechanisms to capture the megaregion economic benefits of HSR and gain additional revenues for Portuguese HSR investments.by Teng Huang.S.M.in Transportatio

Towards an information technology infrastructure cost model

Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2007.Includes bibliographical references (leaves 66-67).Ever since the introduction of the Internet in 1994, one of the defining characteristics of the global economy, particularly in the US, is a dramatic increase in expenditures on Information Technology. While this trend is expected to continue, a major issue for companies of all sizes is the manner in which precise forecasting of future IT cost may be undertaken. The present thesis investigates the possibility that a set of the essential deterministic cost drivers with varying weighted factors may prove capable of estimating total IT infrastructure costs. An online questionnaire was developed for this purpose, and was used to survey senior IT leadership teams. The data collected from this survey was then computed with Analytical Hierarchy Process (AHP) to illustrate the relative importance of different cost drivers. The study revealed three primary findings. First, that a set of essential deterministic cost drivers with varying weighted factors could be used as a general tool for estimating the total cost of IT infrastructure. Second, these different sectors prioritize cost drivers differently from each other. In the Financial Services sector, for instance, the security of the IT network was reported to be of greater importance than the service call response time. In the Technology sector, however, the opposite was true. Third, numerous correlations were found to exist within each cost driver category defined. The correlated nature of these cost parameters may mean that a more parsimonious model may be more predictive of total IT infrastructure costs. It is hoped that these findings may be of benefit to a variety of large and small commercial and government entities, which may be able to use the predictive cost drivers to help eliminate problems related to inaccurate IT cost estimates.(cont.) It is believed that the cost model proposed may be applicable across a variety of economic sectors. In this thesis, its applicability is demonstrated within the 3 financial services and technology sectors. Future research may be useful in evaluating the model further, by increasing the sample size, and by testing the reliability and validity of the cost model within additional economic sectors.by Ken Huang.S.M