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