713 research outputs found
Preparation of cellulose acetate with acetic acid
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1936.by Edward H. Taubman.B.S
What Is Left of Listener Standing? The D.C. Circuit\u27s Continuing Flirtation with a Dying Doctrine
Generating continuous variable quantum codewords in the near-field atomic lithography
Recently, D. Gottesman et al. [Phys. Rev. A 64, 012310 (2001)] showed how to
encode a qubit into a continuous variable quantum system. This encoding was
realized by using non-normalizable quantum codewords, which therefore can only
be approximated in any real physical setup. Here we show how a neutral atom,
falling through an optical cavity and interacting with a single mode of the
intracavity electromagnetic field, can be used to safely encode a qubit into
its external degrees of freedom. In fact, the localization induced by a
homodyne detection of the cavity field is able to project the near-field atomic
motional state into an approximate quantum codeword. The performance of this
encoding process is then analyzed by evaluating the intrinsic errors induced in
the recovery process by the approximated form of the generated codeword.Comment: 9 pages, 5 figure
Squashed States of Light: Theory and Applications to Quantum Spectroscopy
Using a feedback loop it is possible to reduce the fluctuations in one
quadrature of an in-loop field without increasing the fluctuations in the
other. This effect has been known for a long time, and has recently been called
``squashing'' [B.C. Buchler et al., Optics Letters {\bf 24}, 259 (1999)], as
opposed to the ``squeezing'' of a free field in which the conjugate
fluctuations are increased. In this paper I present a general theory of
squashing, including simultaneous squashing of both quadratures and
simultaneous squeezing and squashing. I show that a two-level atom coupled to
the in-loop light feels the effect of the fluctuations as calculated by the
theory. In the ideal limit of light squeezed in one quadrature and squashed in
the other, the atomic decay can be completely suppressed.Comment: 8 pages plus one figure. Submitted to JEOS-B for Dan Walls Special
Issu
Experiments with Lasers and Frequency Doublers
Solid state laser sources, such as diode-pumped Nd:YAG lasers, have given us CW laser light of high power with unprecedented stability and low noise performance. In these lasers most of the technical sources of noise can be eliminated allowing them to be operated close to the theoretical noise limit set by the quantum properties of light. The next step of reducing the noise below the standard limit is known as squeezing. We present experimental progress in generating reliably squeezed light using the process of frequency doubling. We emphasize the long term stability that makes this a truly practical source of squeezed light. Our experimental results match noise spectra calculated with our recently developed models of coupled systems which include the noise generated inside the laser and its interaction with the frequency doubler. We conclude with some observations on evaluating quadrature squeezed states of light
Porphyromonas gingivalis suppresses adaptive immunity in periodontitis, atherosclerosis and Alzheimer’s disease
Porphyromonas gingivalis, a keystone pathogen in chronic periodontitis, has been found to associate with remote body organ inflammatory pathologies including atherosclerosis and Alzheimer’s disease (AD). Although P. gingivalis has a plethora of virulence factors, much of its pathogenicity is surprisingly related to the overall immunosuppression of the host. This review focuses on P. gingivalis aiding suppression of the host’s adaptive immune system involving manipulation of cellular immunological responses specifically T- and B-cells in periodontitis and related conditions. In periodontitis this bacterium inhibits the synthesis of IL-2 and increases humoral responses. This reduces inflammatory responses related to T- and B-cell activation, and subsequent IFN-ɤ secretion by a subset of T cells. The T cells further suppresses upregulation of programmed cell death-1 (PD-1)-receptor on CD+-cells and its ligand PD-L1 on CD11b+- subset of T-cells. IL-2 down-regulates immune response-regulated genes, induces a cytokine pattern in which the Th17 lineage is favored thereby modulating the Th17/ T-regulatory cell (Treg) imbalance. The suppression of IFN-ɤ stimulated release of interferon-inducible protein-10 (IP-10) chemokine ligands [ITAC (CXCL11) and Mig (CXCL9)] by P. gingivalis capsular serotypes, triggers distinct T-cell responses, and contributes to local immune evasion by release of its outer membrane vesicles. In atherosclerosis P. gingivalis reduces Tregs and transforming growth factor beta-1 (TGF-1) and causes imbalance in the Th17 lineage of the Treg population. In Alzheimer’s disease P. gingivalis may affect the blood-brain barrier permeability, and inhibit local IFN-ɤ response by preventing entry of immune cells into the brain. The scarcity of adaptive immune cells in Alzheimer’s disease neuropathology implies P. gingivalis infection of the brain likely causes impaired clearance of insoluble amyloid and induces immunosuppression. By the effective manipulation of the armory of adaptive immune suppression through a plethora of virulence factors P. gingivalis may act as a keystone organism in periodontitis and in related systemic diseases and other remote body inflammatory pathologies
What The Oregon Health Study Can Tell Us About Expanding Medicaid
The recently enacted Patient Protection and Affordable Care Act includes a major expansion of Medicaid to low-income adults in 2014. This paper describes the Oregon Health Study, a randomized controlled trial that will be able to shed some light on the likely effects of such expansions. In 2008, Oregon randomly drew names from a waiting list for its previously closed public insurance program. Our analysis of enrollment into this program found that people who signed up for the waiting list and enrolled in the Oregon Medicaid program were likely to have worse health than those who did not. However, actual enrollment was fairly low, partly because many applicants did not meet eligibility standards.United States. Dept. of Health and Human Services. Office of the Assistant Secretary for Planning and EvaluationCalifornia HealthCare FoundationJohn D. and Catherine T. MacArthur FoundationNational Institute on AgingRobert Wood Johnson FoundationAlfred P. Sloan FoundationUnited States. Social Security Administratio
Globalisation, neo-liberalism and vocational learning: the case of English further education colleges
Further education (FE) has traditionally been a rather unspectacular activity. Lacking the visibility of schools or the prestige of universities, for the vast majority of its existence FE has had a relatively low profile on the margins of English education. Over recent years this situation has altered significantly and further education has undergone profound change. This paper argues that a combination of related factors – neo-liberalism, globalisation, and dominant discourses of the knowledge economy – has acted in synergy to transform FE into a highly performative and marketised sector. Against this backdrop, further education has been assigned a particular role based upon certain narrow and instrumental understandings of skill, employment and economic competitiveness. The paper argues that, although it has always been predominantly working class in nature, FE is now, more than ever, positioned firmly at the lower end of the institutional hierarchy in the highly class-stratified terrain of English education
On robustness against JPEG2000: a performance evaluation of wavelet-based watermarking techniques
With the emergence of new scalable coding standards, such as JPEG2000, multimedia is stored as scalable coded bit streams that may be adapted to cater network, device and usage preferences in multimedia usage chains providing universal multimedia access. These adaptations include quality, resolution, frame rate and region of interest scalability and achieved by discarding least significant parts of the bit stream according to the scalability criteria. Such content adaptations may also affect the content protection data, such as watermarks, hidden in the original content. Many wavelet-based robust watermarking techniques robust to such JPEG2000 compression attacks are proposed in the literature. In this paper, we have categorized and evaluated the robustness of such wavelet-based image watermarking techniques against JPEG2000 compression, in terms of algorithmic choices, wavelet kernel selection, subband selection, or watermark selection using a new modular framework. As most of the algorithms use a different set of parametric combination, this analysis is particularly useful to understand the effect of various parameters on the robustness under a common platform and helpful to design any such new algorithm. The analysis also considers the imperceptibility performance of the watermark embedding, as robustness and imperceptibility are two main watermarking properties, complementary to each other
Employment Testing and Incentives to Learn
Employment tests predict job performance because they measure or are correlated with a large set of malleable developed abilities which are causally related to productivity. Our economy currently under-rewards the achievements that are measured by these tests. Consequently, economic incentives to study hard in high school are minimal and this absence of incentives has contributed to the low levels of achievement in math and science. The paper concludes with a discussion of ways in which employment tests can strengthen incentives to learn
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