1,358 research outputs found

    Resolving single molecule structures with Nitrogen-vacancy centers in diamond.

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    We present theoretical proposals for two-dimensional nuclear magnetic resonance spectroscopy protocols based on Nitrogen-vacancy (NV) centers in diamond that are strongly coupled to the target nuclei. Continuous microwave and radio-frequency driving fields together with magnetic field gradients achieve Hartmann-Hahn resonances between NV spin sensor and selected nuclei for control of nuclear spins and subsequent measurement of their polarization dynamics. The strong coupling between the NV sensor and the nuclei facilitates coherence control of nuclear spins and relaxes the requirement of nuclear spin polarization to achieve strong signals and therefore reduced measurement times. Additionally, we employ a singular value thresholding matrix completion algorithm to further reduce the amount of data required to permit the identification of key features in the spectra of strongly sub-sampled data. We illustrate the potential of this combined approach by applying the protocol to a shallowly implanted NV center addressing a small amino acid, alanine, to target specific hydrogen nuclei and to identify the corresponding peaks in their spectra

    Point-of-care testing for disasters: needs assessment, strategic planning, and future design.

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    Objective evidence-based national surveys serve as a first step in identifying suitable point-of-care device designs, effective test clusters, and environmental operating conditions. Preliminary survey results show the need for point-of-care testing (POCT) devices using test clusters that specifically detect pathogens found in disaster scenarios. Hurricane Katrina, the tsunami in southeast Asia, and the current influenza pandemic (H1N1, "swine flu") vividly illustrate lack of national and global preparedness. Gap analysis of current POCT devices versus survey results reveals how POCT needs can be fulfilled. Future thinking will help avoid the worst consequences of disasters on the horizon, such as extensively drug-resistant tuberculosis and pandemic influenzas. A global effort must be made to improve POC technologies to rapidly diagnose and treat patients to improve triaging, on-site decision making, and, ultimately, economic and medical outcomes

    Keyed Non-Parametric Hypothesis Tests

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    The recent popularity of machine learning calls for a deeper understanding of AI security. Amongst the numerous AI threats published so far, poisoning attacks currently attract considerable attention. In a poisoning attack the opponent partially tampers the dataset used for learning to mislead the classifier during the testing phase. This paper proposes a new protection strategy against poisoning attacks. The technique relies on a new primitive called keyed non-parametric hypothesis tests allowing to evaluate under adversarial conditions the training input's conformance with a previously learned distribution D\mathfrak{D}. To do so we use a secret key Îş\kappa unknown to the opponent. Keyed non-parametric hypothesis tests differs from classical tests in that the secrecy of Îş\kappa prevents the opponent from misleading the keyed test into concluding that a (significantly) tampered dataset belongs to D\mathfrak{D}.Comment: Paper published in NSS 201

    An elementary proof of uniqueness of the particle trajectories for solutions of a class of shear-thinning non-Newtonian 2D fluids

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    We prove some regularity results for a class of two dimensional non-Newtonian fluids. By applying results from [Dashti and Robinson, Nonlinearity, 22 (2009), 735-746] we can then show uniqueness of particle trajectories

    Point-Of-Care Testing Curriculum and Accreditation for Public Health—Enabling Preparedness, Response, and Higher Standards of Care at Points of Need

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    Objectives: To develop awareness of benefits of point-of-care testing (POCT) education in schools of public health, to identify learning objectives for teaching POCT, to enable public health professionals and emergency responders to perform evidence-based diagnosis and triage effectively and efficiently at points of need, and to better improve future standards of care for public health practice, including in limited-resource settings and crisis situations.Methods: We surveyed all U.S. schools of public health, colleges of public health, and public health schools accredited by the Council on Education in Public Health (CEPH). We included accredited public health programs, so that all states offering public health education were represented. We analyzed survey data, public health books, and board certification guidelines. We used PubMed to identify public health curriculum papers, and assessed 2019 CEPH accreditation requirements. We merged POCT knowledge bases to design a new curriculum for teaching public health students and practitioners the principles and practice of POCT.Results: Public health curricula, certification requirements, and textbooks generally do not include POCT instruction. Only one book, Global Point of Care: Strategies for Disasters, Emergencies, and Public Health Resilience, and one online course on public health preparedness address POCT and public health intervention issues. The topic, POC HIV/HCV ED testing, appeared in one course and POC diagnostics in local clinics, in another. Papers on public health curriculum have not incorporated POCT. No curriculum addresses POCT in isolation units during quarantine, despite evidence that recent Ebola virus disease cases in the U.S. and elsewhere proved unequivocally the need for POCT. The modular learning objectives identified in this paper were customized for public health students. Public health graduates can use boot camps, online credentialing, and self-study to acquire POCT skills.Conclusions: Enhancing accreditation requirements, academic training, board certification, and field experience will generate public health healthcare professionals who will rely upon evidence-based medical decision making at points of care, including during crises when time is of the essence. A POCT-enabled public health workforce can help prevent and stop outbreaks. Public health-based medical professionals urgently need the skills necessary to perform POCT and prepare America and other nations for threats portending significant adverse medical, economic, social, and cultural impact

    Development of a lightweight cryogenic insulating system Final report, 30 Jun. 1964 - 31 May 1966

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    Lightweight external panel insulation systems for thermal protection of cryogenic launch vehicle propellant tank

    Heavy ion action on single cells: Cellular inactivation capability of single accelerated heavy ions

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    Heavy ions (HZE-particles) constitute an important part of radiation in space. Although their number is small the high amount of energy transferred by individual particles may cause severe biological effects. Their investigation requires special techniques which were tested by experiments performed at the UNILAC at the GSI (Darmstadt). Diploid yeast was used which is a suitable eucaryotic test system because of its resistance to extreme conditions like dryness and vacuum. Cells were placed on nuclear track detector foils and exposed to ions of different atomic number and energy. To assess the action of one single ion on an individual cell, track parameters and the respective colony forming abilities (CFA) were determined with the help of computer aided image analysis. There is mounting evidence that not only the amount of energy deposited along the particle path, commonly given by the LET, is of importance but also the spatial problem of energy deposition at a submicroscopical scale. It is virtually impossible to investigate track structure effects in detail with whole cell populations and (globally applied) high particle fluences. It is, therefore, necessary to detect the action of simple ions in individual cells. The results show that the biological action depends on atomic number and specific energy of the impinging ions, which can be compared with model calculations of recent track structure models

    Evaluation of the London Measure of Unplanned Pregnancy in a United States population of women

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    Copyright @ 2012 Morof et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Objective: To evaluate the reliability and validity of the London Measure of Unplanned Pregnancy (a U.K.-developed measure of pregnancy intention), in English and Spanish translation, in a U.S. population of women. Methods: A psychometric evaluation study of the London Measure of Unplanned Pregnancy (LMUP), a six-item, self-completion paper measure was conducted with 346 women aged 15–45 who presented to San Francisco General Hospital for termination of pregnancy or antenatal care. Analyses of the two language versions were carried out separately. Reliability (internal consistency) was assessed using Cronbach’s alpha and item-total correlations. Test-retest reliability (stability) was assessed using weighted Kappa. Construct validity was assessed using principal components analysis and hypothesis testing. Results: Psychometric testing demonstrated that the LMUP was reliable and valid in both U.S. English (alpha = 0.78, all item-total correlations .0.20, weighted Kappa = 0.72, unidimensionality confirmed, hypotheses met) and Spanish translation (alpha = 0.84, all item-total correlations .0.20, weighted Kappa = 0.77, unidimensionality confirmed, hypotheses met). Conclusion: The LMUP was reliable and valid in U.S. English and Spanish translation and therefore may now be used with U.S. women.The study was funded by an anonymous donation
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