737 research outputs found

    Generalized Samuel Multiplicities of Monomial Ideals and Volumes

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    We describe conjecturally the generalized Samuel multiplicities c_0,...,c_{d-1} of a monomial ideal I subset K[x_1,...,x_d] in terms of its Newton polyhedron NP(I). More precisely, we conjecture that c_i equals the sum of the normalized (d-1)-volumes of pyramids over the projections of the (d-i-1)-dimensional compact faces of NP(I) along the infinite-directions of i-unbounded facets in which they are contained. For c_0 proofs are known (Guibert, Jeffries and Monta\uf1o) and for c_{d-1} a proof is given

    Efficient measurement-based quantum computing with continuous-variable systems

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    We present strictly efficient schemes for scalable measurement-based quantum computing using continuous-variable systems: These schemes are based on suitable non-Gaussian resource states, ones that can be prepared using interactions of light with matter systems or even purely optically. Merely Gaussian measurements such as optical homodyning as well as photon counting measurements are required, on individual sites. These schemes overcome limitations posed by Gaussian cluster states, which are known not to be universal for quantum computations of unbounded length, unless one is willing to scale the degree of squeezing with the total system size. We establish a framework derived from tensor networks and matrix product states with infinite physical dimension and finite auxiliary dimension general enough to provide a framework for such schemes. Since in the discussed schemes the logical encoding is finite-dimensional, tools of error correction are applicable. We also identify some further limitations for any continuous-variable computing scheme from which one can argue that no substantially easier ways of continuous-variable measurement-based computing than the presented one can exist.Comment: 13 pages, 3 figures, published versio

    Shared Responsibilities for Nuclear Disarmament: A Global Debate

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    Presents Sagan's 2009 paper calling for rethinking the balance of responsibilities and the relationship between articles in the Nuclear Non-Proliferation Treaty with seven response papers by international scholars about how to pursue nuclear disarmament

    Patient satisfaction, feasibility and reliability of satisfaction questionnaire among patients with pulmonary tuberculosis in urban Uganda: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>A comprehensive understanding of the barriers to and facilitators of poor tuberculosis (TB) treatment outcome is still lacking; posing a major obstacle to finding effective solutions. Assessment of patient satisfaction in TB programs would contribute to the understanding of gaps in healthcare delivery and the specific needs of individual patients. However, tools for assessing patient satisfaction are lacking.</p> <p>Objective</p> <p>To establish patient satisfaction, the feasibility and reliability of a questionnaire for healthcare service satisfaction and a questionnaire for satisfaction with information received about TB medicines among adult TB patients attending public and private program clinics in Kampala, Uganda.</p> <p>Methods</p> <p>In a cross-sectional study, we recruited 133 patients of known HIV status and confirmed pulmonary TB receiving care at the public and private hospitals in Kampala, Uganda. Participants were enrolled based on length of TB treatment as follows: starting therapy, completed two months of therapy, and completed eight months of therapy. A translated and standardized 13-item patient healthcare service satisfaction questionnaire (PS-13) and the Satisfaction with Information about Medicines Scale (SIMS) tool were administered by trained interviewers. Factor analysis was used to systematically group the PS-13 questionnaire into three factors of technical quality of care, responsiveness to patient preference, and management of patient preference satisfaction subscales. The SIMS tool was analyzed with two subscales of information about the action and usage of medication and the potential problems with medication.</p> <p>Results</p> <p>Of the 133 participants, 35% (46/133) were starting, 33% (44/133) had completed two months, and 32% (43/133) had completed eight months of TB therapy. The male to female and public to private hospital ratios in the study population were 1:1. The PS-13 and the SIMS tools were highly acceptable and easily administered. Both scales and the subscales demonstrated acceptable internal consistency with Cronbach's alpha above 0.70. Patients that were enrolled at the public hospital had relatively lower PS-13 satisfaction scores (0.48 (95% confidence interval (CI), 0.42 - 0.52)), (0.86 (95% CI, 0.81 - 0.90)) for technical quality of care and responsiveness to patient preferences, respectively compared to patients that were enrolled at the private hospital. For potential problems SIMS subscale, male patients that were recruited at the public hospital had relatively lower satisfaction scores (0.58 (95% CI, 0.40 - 0.86)) compared to female patients after adjusting for other factors. Similarly, patients that had completed eight months of TB treatment had relatively higher satisfaction scores (1.23 (95% CI, 1.06 - 1.44)) for action and usage SIMS subscale, and higher satisfaction scores (1.09 (95% CI, 1.03 - 1.16)) for management of patient preference (PS-13 satisfaction subscale) compared to patients that were starting treatment, respectively.</p> <p>Conclusion</p> <p>The study provides preliminary evidence that the PS-13 service satisfaction and the SIMS tools are reliable measures of patient satisfaction in TB programs. Satisfaction score findings suggest differences in patient satisfaction levels between public and private hospitals; between patients starting and those completing TB therapy.</p

    Feasibility, reliability and validity of health-related quality of life questionnaire among adult pulmonary tuberculosis patients in urban Uganda: cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Despite the availability of standard instruments for evaluating health-related quality life (HRQoL), the feasibility, reliability, and validity of such instruments among tuberculosis (TB) patients in different populations of sub-Saharan Africa where TB burden is of concern, is still lacking.</p> <p>Objective</p> <p>We established the feasibility, reliability, and validity of the Medical Outcomes Survey (MOS) in assessing HRQoL among patients with pulmonary tuberculosis in Kampala, Uganda.</p> <p>Methods</p> <p>In a cross-sectional study, 133 patients with known HIV status and confirmed pulmonary TB disease were recruited from one public and one private hospital. Participants were enrolled based on duration of TB treatment according to the following categories: starting therapy, two months of therapy, and eight completed months of therapy. A translated and culturally adapted standardized 35-item MOS instrument was administered by trained interviewers. The visual analogue scale (VAS) was used to cross-validate the MOS.</p> <p>Results</p> <p>The MOS instrument was highly acceptable and easily administered. All subscales of the MOS demonstrated acceptable internal consistency with Cronbach's alpha above 0.70 except for role function that had 0.65. Each dimension of the MOS was highly correlated with the dimension measured concurrently using the VAS providing evidence of validity. Construct validity demonstrated remarkable differences in the functioning status and well-being among TB patients at different stages of treatment, between patients attending public and private hospitals, and between men and women of older age. Patients who were enrolled from public hospital had significantly lower HRQoL scores (0.78 (95% confidence interval (CI); 0.64-0.95)) for perceived health but significantly higher HRQoL scores (1.15 (95% CI; 1.06-1.26)) for health distress relative to patients from private hospital. Patients who completed an 8 months course of TB therapy had significantly higher HRQoL scores for perceived health (1.93 (95% CI; 1.19-3.13)), health distress subscales (1.29 (95% CI; 1.04-1.59)) and mental health summary scores (1.27 (95% CI; 1.09-1.48)) relative to patients that were starting therapy in multivariable analysis. Completion of 8 months TB therapy among patients who were recruited from the public hospital was associated with a significant increase in HRQoL scores for quality of life subscale (1.26 (95% CI; 1.08-1.49)), physical health summary score (1.22 995% CI; 1.04-1.43)), and VAS (1.08 (95% CI; 1.01-1.15)) relative to patients who were recruited from the private hospital. Older men were significantly associated with lower HRQoL scores for physical health summary score (0.68 (95% CI; 0.49-0.95)) and VAS (0.87 (95% CI; 0.75-0.99)) relative to women of the same age group. No differences were seen between HIV positive and HIV negative patients.</p> <p>Conclusion</p> <p>The study provides evidence that the MOS instrument is valid, and reliably measures HRQoL among TB patients, and can be used in a wide variety of study populations. The HRQoL differed by hospital settings, by duration of TB therapy, and by gender in older age groups.</p

    Wie viel Arbeit macht die Aufzucht von Ökologischen Junghennen? Arbeitwirtschaftlicher Vergleich der konventionellen und ökologischen Aufzucht von Legehennen

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    Organic pullets are reared with daylight and are not beak-trimmed. Therefore, certain provisions are needed in order to prevent feather-pecking and cannibalism. Respec-tive guidelines are set by the German Organic Associations. It was the goal of this study to investigate whether the higher rearing standards are associated with an increased labour demand compared to conventional rearing systems. Using a ques-tionnaire, data from 32 hen-houses (10 conventional and 6 organic barn systems, 10 conventional and 6 organic aviary systems) about duration and number of working procedures were collected and exemplary models calculated. Total labour demand was between 2.36 and 7.37 worker`s hours/100 pullets. It did not differ between or-ganic and conventional rearing when comparing similar flock sizes, but were partly differently allocated to the different working procedures. On average, organic farms had smaller flocks, and there was a large influence of flock size on labour demand with small houses requiring most labour per hen. Also aviaries were more labour demanding than barn systems, but were usually associated with higher flock sizes. Our results indicate that improved pullet rearing that allows the birds to perform their natural behaviour more completely, does not necessarily cause higher labour re-quirements

    In Vitro Formation of Urinary Stones : Generation of Spherulites of Calcium Phosphate in Gel and Overgrowth with Calcium Oxalate Using a New Flow Model of Crystallization

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    Calcium phosphate (CaP) has been detected in the majority of urinary stones containing predominantly calcium oxalate (CaOx). Therefore, crystal phases of CaP might play an important role with respect to the formation of urinary calcium stones in general. Very often, CaP found in stones or tissue of human kidney occurs in the shape of small spherulites. In this paper, we report on a new flow model of crystallization (FMCG), which has been used to generate spherulites of CaP in a gel matrix of 1% agar-agar at 37°C from a supersaturated, metastable solution continuously flowing over the gel surface. Scanning electron microscopy (SEM), X-ray diffraction and microscopic Fourier transformed infrared spectroscopy (FTIR) revealed that the particles formed (diameter: up to 200 Οm) consisted of a poorly crystal-line core of carbonatoapatite which was partly surrounded by a well-crystallized shell of octacalcium phosphate (OCP) showing radially oriented sheet-like structures. Subsequently, CaOx was grown on these spherulites from a flow of a correspondingly supersaturated solution conducted over the gel matrix. It could be shown by SEM that growth of calcium oxalate monohydrate (COM) was characteristically induced by the OCP shell. Radial sheet-like forms of OCP were directly continued by COM showing a certain radial orientation. The model of crystallization in gel matrices applied here should be well-suited to simulate the process of urinary stone formation under in vitro conditions

    Fast quantum key distribution with decoy number states

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    We investigate the use of photon number states to identify eavesdropping attacks on quantum key distribution (QKD) schemes. The technique is based on the fact that different photon numbers traverse a channel with different transmittivity. We then describe two QKD schemes that utilize this method, one of which overcomes the upper limit on the key generation rate imposed by the dead time of detectors when using a heralded source of photons.Comment: 15 pages, 6 figures; Accepted to J. Mod. Op

    Analysing the learning pathways of students in a large flipped engineering course

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    Recent advancements in educational technologies (learning management systems, online discussion forums, peer-learning tools) coupled with new methods of course delivery (e.g. blended, flipped, MOOCs) provide significant opportunities for universities to deliver challenging, high quality, yet engaging curriculum for students. In this paper, we examine the variations and similarities of student's approaches to learning (learning pathways) by examining how well they performed in a large (N ~ 1000 student) first year engineering flipped classroom. The analysis focused on student's performance in their assessment (formative and summative) as well as their online interaction with a range of tools purposely built to support students through peer learning and acquisition of resources and expertise. Analysis using k-means clustering reveals that students do in fact adopt a variety of successful pathways through the course. The unique aspects of this work lie in the use of analytics algorithms that whilst perhaps routinely utilised in data mining, are not as well utilised in better understanding patterns (successful or otherwise) of student interactions within a technology enhanced active learning environment that integrates theory with engineering practice

    Simulations of Photon Detection in SiPM Number-Resolving Detectors

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    Number-resolving single photon detectors are essential for the implementation of numerous innovative quantum information schemes. While several number-discriminating techniques have been previously presented, the Silicon Photo-Multiplier (SiPM) detector is a promising candidate due its rather simple integration in optical setups. On the other hand, the photon statistics obtained with the SiPM detector suffer from inaccuracies due to inherent distortions which depend on the geometrical properties of the SiPM. We have simulated the detection process in a SiPM detector and studied these distortions. We use results from the simulation in order to interpret experimental data and study the limits in which available models prevail
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