525 research outputs found

    Systematic literature review: quality of life associated with insulin pump use in type 1 diabetes

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    WSTĘP. W niniejszej pracy przedstawiono systematyczny przegląd opublikowanej literatury w celu odpowiedzi na pytanie, czy ciągły podskórny wlew insuliny (CSII) poprawia jakość życia chorych na cukrzycę typu 1. MATERIAŁ I METODY. Przeszukano elektroniczne bazy danych oraz opublikowane wyniki badań, a po konsultacji z dwiema grupami ekspertów wybrano istotne prace, które opublikowano do lipca 2005 roku. Aby zidentyfikować doniesienia spełniające wybrane kryteria selekcji, zastosowano wieloetapowy proces wyboru, a następnie poddawano prace krytycznej ocenie. WYNIKI. Po analizie tytułów i streszczeń do dalszego etapu wybrano 84 potencjalnie odpowiednie prace opublikowane w wymienionym przedziale czasowym. Z tych doniesień wyodrębniono 28 pełnych artykułów, z których 17 spełniało kryteria włączenia do analizy. Z istniejących danych piśmiennictwa wynikają rozbieżne wnioski. Spośród 5 randomizowanych, kontrolowanych badań poddanych analizie z 3 wynikały niejednoznaczne wnioski, w 1 wskazywano na poprawę jakości życia, a w 1 nie dowiedziono korzyści dotyczących jakości życia. WNIOSKI. Wyniki badań przedstawiają sprzeczne wnioski dotyczące poprawy jakości życia chorych na cukrzycę typu 1 stosujących terapię CSII. Istniejące prace mają wady powodujące, że wnioskowanie co do jakości życia pacjentów stosujących terapię pompą insulinową jest trudne. Brakuje przekonujących dowodów, że korzyści ze stosowania CSII nie istnieją lub inaczej - niewłaściwa metodologia i niespójna analiza dotycząca jakości życia utrudniają ocenę tego zagadnienia. Brak udowodnionego korzystnego wpływu na jakość życia prawdopodobnie wiąże się z przedstawionymi uchybieniami w badaniach, a nie z faktem, że terapia polegająca na zastosowaniu pomp insulinowych nie koreluje z poprawą jakości życia chorych.AIM. To review systematically the published literature addressing whether continuous subcutaneous insulin infusion (CSII) provides any quality of life benefits to people with type 1 diabetes. METHODS. Electronic databases and published references were searched and a consultation with two professional groups was undertaken to identify re levant studies published up to July 2005. A multistep selection process was then undertaken to identify those articles which met the specific selection criteria, which were then critically reviewed. RESULTS. Eighty-four potential relevant articles were identified from examination of titles and abstracts published during the specified time frame. Of these, 28 articles were retrieved in full text, of which 17 fulfilled the specific criteria for inclusion. Mixed results emerged from existing literature. Of the five randomized controlled trials, three reported mixed results, with one study reporting quality of life benefits and one reporting no evidence of quality of life benefits. CONCLUSIONS. There is conflicting evidence reported in the various studies on the quality of life benefits of CSII in type 1 diabetes. Existing research is flawed, making a judgement about the quality of life benefits of insulin pump use difficult. There is no strong evidence against quality of life benefits associated with CSII or otherwise, with poor methodology and inconsistent assessment of quality of life clouding the issue. The lack of reported benefit is probably a function of this rather than pump therapy not offering any quality of life benefits

    Deciding Full Branching Time Logic by Program Transformation

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    We present a method based on logic program transformation, for verifying Computation Tree Logic (CTL*) properties of finite state reactive systems. The finite state systems and the CTL* properties we want to verify, are encoded as logic programs on infinite lists. Our verification method consists of two steps. In the first step we transform the logic program that encodes the given system and the given property, into a monadic ω -program, that is, a stratified program defining nullary or unary predicates on infinite lists. This transformation is performed by applying unfold/fold rules that preserve the perfect model of the initial program. In the second step we verify the property of interest by using a proof method for monadic ω-program

    Secure quantum key distribution using squeezed states

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    We prove the security of a quantum key distribution scheme based on transmission of squeezed quantum states of a harmonic oscillator. Our proof employs quantum error-correcting codes that encode a finite-dimensional quantum system in the infinite-dimensional Hilbert space of an oscillator, and protect against errors that shift the canonical variables p and q. If the noise in the quantum channel is weak, squeezing signal states by 2.51 dB (a squeeze factor e^r=1.34) is sufficient in principle to ensure the security of a protocol that is suitably enhanced by classical error correction and privacy amplification. Secure key distribution can be achieved over distances comparable to the attenuation length of the quantum channel.Comment: 19 pages, 3 figures, RevTeX and epsf, new section on channel losse

    Linear optics substituting scheme for multi-mode operations

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    We propose a scheme allowing a conditional implementation of suitably truncated general single- or multi-mode operators acting on states of traveling optical signal modes. The scheme solely relies on single-photon and coherent states and applies beam splitters and zero- and single-photon detections. The signal flow of the setup resembles that of a multi-mode quantum teleportation scheme thus allowing the individual signal modes to be spatially separated from each other. Some examples such as the realization of cross-Kerr nonlinearities, multi-mode mirrors, and the preparation of multi-photon entangled states are considered.Comment: 11 pages, 4 eps-figures, using revtex

    Mammalian sphingoid bases: Biophysical, physiological and pathological properties

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    Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules, and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease

    Continuous variable quantum cryptography

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    We propose a quantum cryptographic scheme in which small phase and amplitude modulations of CW light beams carry the key information. The presence of EPR type correlations provides the quantum protection.Comment: 8 pages, 3 figure

    Defining and identifying crop landraces

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    Awareness of the need for biodiversity conservation is now universally accepted, but most often recent conservation activities have focused on wild species. Crop species and the diversity between and within them has significant socioeconomic as well as heritage value. The bulk of genetic diversity in domesticated species is located in traditional varieties maintained by traditional farming systems. These traditional varieties, commonly referred to as landraces, are severely threatened by genetic extinction primarily due to their replacement by modern genetically uniform varieties. The conservation of landrace diversity has been hindered in part by the lack of an accepted definition to define the entity universally recognized as landraces. Without a definition it would be impossible to prepare an inventory and without an inventory changes in landrace constituency could not be recognized over time. Therefore, based on a literature review, workshop discussion and interviews with key informants, common characteristics of landraces were identified, such as: historical origin, high genetic diversity, local genetic adaptation, recognizable identity, lack of formal genetic improvement, and whether associated with traditional farming systems. However, although these characteristics are commonly present they are not always all present for any individual landrace; several crop-specific exceptions were noted relating to crop propagation method (sexual or asexual), breeding system (self-fertilized or cross-fertilized species), length of formal crop improvement, seed management (selection or random propagation) and use. This paper discusses the characteristics that generally constitute a landrace, reviews the exceptions to these characteristics and provides a working definition of a landrace. The working definition proposed is as follows: `a landrace is a dynamic population(s) of a cultivated plant that has historical origin, distinct identity and lacks formal crop improvement, as well as often being genetically diverse, locally adapted and associated with traditional farming systems

    Experimental Vacuum Squeezing in Rubidium Vapor via Self-Rotation

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    We report the generation of optical squeezed vacuum states by means of polarization self-rotation in rubidium vapor following a proposal by Matsko et al. [Phys. Rev. A 66, 043815 (2002)]. The experimental setup, involving in essence just a diode laser and a heated rubidium gas cell, is simple and easily scalable. A squeezing of 0.85+-0.05 dB was achieved

    Revisiting consistency conditions for quantum states of systems on closed timelike curves: an epistemic perspective

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    There has been considerable recent interest in the consequences of closed timelike curves (CTCs) for the dynamics of quantum mechanical systems. A vast majority of research into this area makes use of the dynamical equations developed by Deutsch, which were developed from a consistency condition that assumes that mixed quantum states uniquely describe the physical state of a system. We criticise this choice of consistency condition from an epistemic perspective, i.e., a perspective in which the quantum state represents a state of knowledge about a system. We demonstrate that directly applying Deutsch's condition when mixed states are treated as representing an observer's knowledge of a system can conceal time travel paradoxes from the observer, rather than resolving them. To shed further light on the appropriate dynamics for quantum systems traversing CTCs, we make use of a toy epistemic theory with a strictly classical ontology due to Spekkens and show that, in contrast to the results of Deutsch, many of the traditional paradoxical effects of time travel are present.Comment: 10 pages, 6 figures, comments welcome; v2 added references and clarified some points; v3 published versio

    Conditional linear-optical measurement schemes generate effective photon nonlinearities

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    We provide a general approach for the analysis of optical state evolution under conditional measurement schemes, and identify the necessary and sufficient conditions for such schemes to simulate unitary evolution on the freely propagating modes. If such unitary evolution holds, an effective photon nonlinearity can be identified. Our analysis extends to conditional measurement schemes more general than those based solely on linear optics.Comment: 16 pages, 2 figure
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