417 research outputs found

    Projection of two biphoton qutrits onto a maximally entangled state

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    Bell state measurements, in which two quantum bits are projected onto a maximally entangled state, are an essential component of quantum information science. We propose and experimentally demonstrate the projection of two quantum systems with three states (qutrits) onto a generalized maximally entangled state. Each qutrit is represented by the polarization of a pair of indistinguishable photons - a biphoton. The projection is a joint measurement on both biphotons using standard linear optics elements. This demonstration enables the realization of quantum information protocols with qutrits, such as teleportation and entanglement swapping.Comment: 4 pages, 3 figures, published versio

    Serostatus disclosure among adults with HIV in the era of HIV therapy

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    Serostatus disclosure is an important component of secondary HIV prevention with potential benefits for both the individual by experiencing increased social support and society by reducing HIV transmission risk behaviors. This cross-sectional study assessed disclosure patterns to sex partners, family members, and friends by sociodemographic and HIV-related factors among an urban, Midwestern U.S. HIV clinic population (n=809); a majority of whom were African American and male with a mean age of 41 years. Almost three quarters (n=596) of the sample was currently receiving HIV therapy, with 68% (n=404) successfully suppressing their HIV viral loads. Among sexually activity individuals, 97% reported disclosing their serostatus to sex partners. This high rate of disclosure to sex partners suggests that social desirability may play a role in this self-reported measure. Approximately half of the sample (n=359) disclosed to at least one family member and 60% (n=474) disclosed to at least one friend. Disclosing to family members occurred more often among participants who were unemployed and endorsed depressive disorder symptoms (p<0.05 for all). Disclosing to friends occurred more frequently among women, Caucasians and those who completed higher levels of education (p<0.001 for all). HIV disclosure and disease severity were unassociated. Given the chronic nature of HIV care, additional research is needed to develop interventions to facilitate timely disclosure of HIV serostatus

    Mathematical Modeling of a Bioluminescent E. Coli Based Biosensor

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    In this work we present a mathematical model for the bioreporter activity of&nbsp;an E. coli based bioluminescent bioreporter. This bioreporter is based on a genetically&nbsp;modified E. coli which harbors the recA promoter, a member of the bacterial SOS&nbsp;response, fused to the bacterial luminescence (lux) genes. This bioreporter responds&nbsp;to the presence of DNA damaging agents such as heavy metals, H2O2 and Nalidixic&nbsp;Acid (NA) that activate the SOS response. In our mathematical model we implemented&nbsp;basic physiological mechanisms such as: the penetration of the NA into the biosensor;&nbsp;gyrase enzyme inhibition by the NA; gyrase level regulation; creation of chromosomal&nbsp;DNA damage; DNA repair and release of ssDNA into the cytoplasm; SOS induction and&nbsp;chromosomal DNA repair; activation of lux genes by the fused recA promoter carried on&nbsp;a plasmidal DNA; transcription and translation of the luminescence responsible enzymes;&nbsp;luminescence cycle; energy molecules level regulation and the regulation of the O2&nbsp;consumption. The mathematical model was defined using a set of ordinary differential&nbsp;equations (ODE) and solved numerically. We simulated the system for different concentrations of NA in water for specific biosensors concentration, and under limited O2&nbsp;conditions. The simulated results were compared to experimental data and satisfactory&nbsp;matching was obtained. This manuscript presents a proof of concept showing that&nbsp;real biosensors can be modeled and simulated. This sets the ground to the next stage&nbsp;of implementing a comprehensive physiological model using experimentally extracted&nbsp;parameters. Following the completion of the next stage, it will be possible to construct&nbsp;a “Computer Aided Design” tool for the simulation of the genetically engineered&nbsp;biosensors. We define a term “bioCAD” for a Biological System Computer Aided Design.&nbsp;The specific bioCAD that is described here is aimed towards whole cell biosensors which&nbsp;are under investigation today for functional sensing. Usage of the bioCAD will improve&nbsp;the biosensors design process and boost their performance. It will also reduce Non&nbsp;Recurring Engineering (NRE) cost and time. Finally, using a parameterized solution&nbsp;will allow fair and quick evaluation of whole cell biosensors for various applications

    Local crystallographic texture and voiding in passivated copper interconnects

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    A correlation between local crystallographic texture and stress‐induced void formation in tantalum‐encapsulated, copper interconnects was revealed by electron backscattering diffraction studies in a scanning electron microscope. Lines exhibiting an overall stronger 〈111âŒȘ texture showed better resistance to void formation. Furthermore, grains adjacent to voids exhibited weaker 〈111âŒȘ texture than grains in unvoided regions of the same line. The locally weaker 〈111âŒȘ texture at voided locations suggests the presence of higher diffusivity, twist boundaries. This work, which represents the first characterization of local texture in stress voided, copper lines, helps to elucidate the relative importance of the thermodynamic and kinetic factors which govern void formation and growth. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70319/2/APPLAB-69-26-4017-1.pd

    Emerging technologies to measure neighborhood conditions in public health: Implications for interventions and next steps

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    Adverse neighborhood conditions play an important role beyond individual characteristics. There is increasing interest in identifying specific characteristics of the social and built environments adversely affecting health outcomes. Most research has assessed aspects of such exposures via self-reported instruments or census data. Potential threats in the local environment may be subject to short-term changes that can only be measured with more nimble technology. The advent of new technologies may offer new opportunities to obtain geospatial data about neighborhoods that may circumvent the limitations of traditional data sources. This overview describes the utility, validity and reliability of selected emerging technologies to measure neighborhood conditions for public health applications. It also describes next steps for future research and opportunities for interventions. The paper presents an overview of the literature on measurement of the built and social environment in public health (Google Street View, webcams, crowdsourcing, remote sensing, social media, unmanned aerial vehicles, and lifespace) and location-based interventions. Emerging technologies such as Google Street View, social media, drones, webcams, and crowdsourcing may serve as effective and inexpensive tools to measure the ever-changing environment. Georeferenced social media responses may help identify where to target intervention activities, but also to passively evaluate their effectiveness. Future studies should measure exposure across key time points during the life-course as part of the exposome paradigm and integrate various types of data sources to measure environmental contexts. By harnessing these technologies, public health research can not only monitor populations and the environment, but intervene using novel strategies to improve the public health

    Impact of internalized stigma on HIV prevention behaviors among HIV-infected individuals seeking HIV care in Kenya

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    In general, an initial diagnosis of HIV is likely to be correlated with the onset of HIV stigma. HIV-positive individuals are likely to internalize stigma, may suffer from psychosocial issues, or engage in maladaptive behaviors to cope with the diagnosis. Internalized stigma stems from fear of stigmatization also known as felt stigma. The current study examined the impact of HIV felt stigma on overall health and success of HIV prevention behaviors among 370 participants living with HIV and receiving care at an urban HIV clinic in Kenya. An 18-item instrument was cross culturally adapted to measure felt stigma. Descriptive and logistic regression analyses examined the data. Findings indicate that 25.9% (n=96) of participants who reported experiencing high levels of felt stigma related to other people's attitudes toward their condition, ostracizing, and a disruption of their personal life, were likely to not adhere to prescribed HIV medication and not disclose their HIV serostatus to one other person. Those who also experienced felt stigma related to a disruption of their personal lives while mediated by depression were likely to report poor overall health. Findings support having HIV clinics and interventions develop relevant HIV prevention strategies that focus on the emerging dimensions of felt stigma which can significantly impact disclosure of serostatus, medication adherence, and overall health

    On the Spectrum of Direct Gaugino Mediation

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    In direct gauge mediation, the gaugino masses are anomalously small, giving rise to a split SUSY spectrum. Here we investigate the superpartner spectrum in a minimal version of "direct gaugino mediation." We find that the sfermion masses are comparable to those of the gauginos - even in the hybrid gaugino-gauge mediation regime - if the messenger scale is sufficiently small.Comment: 21 pages, 4 figures; V2: refs. adde

    Auditable Compressed Storage

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    Outsourcing data to the cloud for personal use is becoming an everyday trend rather than an extreme scenario. The frequent outsourcing of data increases the possible attack window because users do not fully control their personal files. Typically, once there are established secure channels between two endpoints, communication is considered secure. However, in the cloud model the receiver–the cloud–cannot be fully trusted, either because it has been under adversarial control, or because it acts maliciously to increase its revenue by deleting infrequent accessed file blocks. One approach used by current literature to address the aforementioned security concerns is via Remote Data Integrity Checking (RDIC) protocols, whereby a data owner can challenge an untrusted cloud service provider (CSP) to prove faithful storage of its data. Current RDIC protocols assume that the original data format remains unchanged. However, users may wish to compress their data in order to enjoy less charges. In that case, current RDIC protocols become impractical because, each time compression happens on a file, the user has to run a new RDIC protocol. In this work we initiate the study for Auditable Compressed Storage (ACS). After defining the new model we instantiate two protocols for different widely used compression techniques: run length encoding and Huffman encoding. In contrast with conventional RDIC, our protocols allow a user to delegate the compression to the cloud in a provably secure way: The client can verify correctness of compression without having to download the entire uncompressed file and check it against the compressed one

    SegSlice: Towards a New Class of Secure Programming Primitives for Trustworthy Platforms

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    Abstract. The TPM is a fairly passive entity. As a result, it can be difficult to involve the TPM in measurements of software trustworthiness beyond simple load-time hashing of static program code. We suggest an approach to dynamic, runtime measurement of software trustworthiness properties as they relate to code-data owernship relationships. We outline a system, SegSlice, that actively involves the TPM in fine-grained labeling and measurement of code slices and the data that these slices operate on. SegSlice requires no changes to x86 hardware, and it relies on the relatively underused x86 segmentation mechanism to mediate access to data events.
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