1,044 research outputs found

    Theory of noise suppression in {\Lambda}-type quantum memories by means of a cavity

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    Quantum memories, capable of storing single photons or other quantum states of light, to be retrieved on-demand, offer a route to large-scale quantum information processing with light. A promising class of memories is based on far-off-resonant Raman absorption in ensembles of Λ\Lambda-type atoms. However at room temperature these systems exhibit unwanted four-wave mixing, which is prohibitive for applications at the single-photon level. Here we show how this noise can be suppressed by placing the storage medium inside a moderate-finesse optical cavity, thereby removing the main roadblock hindering this approach to quantum memory.Comment: 10 pages, 3 figures. This paper provides the theoretical background to our recent experimental demonstration of noise suppression in a cavity-enhanced Raman-type memory ( arXiv:1510.04625 ). See also the related paper arXiv:1511.05448, which describes numerical modelling of an atom-filled cavity. Comments welcom

    Comparison of Ion Balance and Nitrogen Metabolism in Old and Young Leaves of Alkali-Stressed Rice Plants

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    BACKGROUND: Alkali stress is an important agricultural contaminant and has complex effects on plant metabolism. The aim of this study was to investigate whether the alkali stress has different effects on the growth, ion balance, and nitrogen metabolism in old and young leaves of rice plants, and to compare functions of both organs in alkali tolerance. METHODOLOGY/PRINCIPAL FINDINGS: The results showed that alkali stress only produced a small effect on the growth of young leaves, whereas strongly damaged old leaves. Rice protected young leaves from ion harm via the large accumulation of Na(+) and Cl(-) in old leaves. The up-regulation of OsHKT1;1, OsAKT1, OsHAK1, OsHAK7, OsHAK10 and OsHAK16 may contribute to the larger accumulation of Na(+) in old leaves under alkali stress. Alkali stress mightily reduced the NO(3)(-) contents in both organs. As old leaf cells have larger vacuole, under alkali stress these scarce NO(3)(-) was principally stored in old leaves. Accordingly, the expression of OsNRT1;1 and OsNRT1;2 in old leaves was up-regulated by alkali stress, revealing that the two genes might contribute to the accumulation of NO(3)(-) in old leaves. NO(3)(-) deficiency in young leaves under alkali stress might induce the reduction in OsNR1 expression and the subsequent lacking of NH(4)(+), which might be main reason for the larger down-regulation of OsFd-GOGAT and OsGS2 in young leaves. CONCLUSIONS/SIGNIFICANCE: Our results strongly indicated that, during adaptation of rice to alkali stress, young and old leaves have distinct mechanisms of ion balance and nitrogen metabolism regulation. We propose that the comparative studies of young and old tissues may be important for abiotic stress tolerance research

    Posthumous Medical Data Donation: The Case for a Legal Framework

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    This article explores the options for establishing a legal framework for posthumous medical data donation (PMDD). This concept has not been discussed in legal scholarship to date at all. The paper is, therefore, a first legal study of PMDD, aiming to address the gap and shed light on the most significant legal issues that could affect this concept. The paper starts by looking at the protection of the deceased’s health records and medical data, finding that this protection in law is more extensive than the general protection of the deceased’s personal data, or the protection of post-mortem privacy as a concept. The paper then investigates key issues around ownership and succession of personal data, including medical and health-related data, and how these could affect PMDD and its legal framework. The author then goes on to explore some parallels with organ donation to determine whether there are some lessons to be learned from this comparable regulatory framework. The paper concludes with the discussion around the need for a Code for posthumous medical data donation developed by the Digital Ethics Lab at the Oxford Internet Institute, and a more formal regime that would enable and facilitate this practice. Here, the author proposes key law reforms in the area of data protection and governance related to PMDD. These reforms would include amendments to the general data protection ideally, to ensure harmonisation and consistency across the EU, as well as between the general and sector-specific data protection laws and policies. These changes would contribute to legal and regulatory clarity and would help implement this important and valuable practice, which aims to facilitate research and advances in medical treatments and care

    Dramatic pain relief and resolution of bone inflammation following pamidronate in 9 pediatric patients with persistent chronic recurrent multifocal osteomyelitis (CRMO)

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    <p>Abstract</p> <p>Background</p> <p>Chronic recurrent multifocal osteomyelitis (CRMO) is an inflammatory, non-infectious osteopathy that affects predominantly patients ≀ 18 years of age. There is no uniformly effective treatment. Our objective is to describe clinical, magnetic resonance imaging (MRI), and bone resorption response to intravenous pamidronate in pediatric CRMO.</p> <p>Methods</p> <p>We report our prospectively documented experience with all CRMO patients treated with pamidronate between 2003 and 2008 at a tertiary pediatric centre. Pamidronate was administered as intravenous cycles. The dose of pamidronate varied among subjects but was given as monthly to every 3 monthly cycles depending on the distance the patient lived from the infusion center. Maximum cumulative dose was ≀ 11.5 mg/kg/year. Pamidronate treatment was continued until resolution of MRI documented bone inflammation. Visual analog scale for pain (VAS) and bone resorption marker urine N-telopeptide/urine creatinine (uNTX/uCr) were measured at baseline, preceding each subsequent pamidronate treatment, at final follow-up, and/or at time of MRI confirmed CRMO flare. MRI of the affected site(s) was obtained at baseline, preceding every 2<sup>nd </sup>treatment, and with suspected CRMO recurrence.</p> <p>Results</p> <p>Nine patients (5 F: 4 M) were treated, with a median (range) age at treatment of 12.9 (4.5–16.3) years, and median (range) duration of symptoms of 18 (6–36) months. VAS decreased from 10/10 to 0–3/10 by the end of first 3–day treatment for all patients. The mean (range) time to complete MRI resolution of bone inflammation was 6.0 (2–12) months. The mean (confidence interval (CI)) baseline uNTX/uCr was 738.83 (CI 464.25, 1013.42)nmol/mmol/creatinine and the mean (CI) decrease from baseline to pamidronate discontinuation was 522.17 (CI 299.77, 744.56)nmol/mmol/creatinine. Median (range) of follow-up was 31.4 (24–54) months. Four patients had MRI confirmed CRMO recurrence, which responded to one pamidronate re-treatment. The mean (range) uNTX/uCr change as a monthly rate from the time of pamidronate discontinuation to flare was 9.41 (1.38–19.85)nmol/mmol/creatinine compared to -29.88 (-96.83–2.01)nmol/mmol/creatinine for patients who did not flare by the time of final follow-up.</p> <p>Conclusion</p> <p>Pamidronate resulted in resolution of pain and MRI documented inflammation in all patients. No patient flared while his/her uNTX/uCr remained suppressed. We propose that pamidronate is an effective second-line therapy in persistent CRMO.</p

    Mannitol transport and mannitol dehydrogenase activities are coordinated in olea europaea under salt and osmotic stresses

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    This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Plant and Cell Physiology following peer review. The definitive publisher-authenticated version is available online at http://pcp.oxfordjournals.org/cgi/content/abstract/pcr121? ijkey=6orgUM5fkIjedYn&keytype=refThe intracellular accumulation of organic compatible solutes functioning as osmoprotectants, such as polyols, is an important response mechanism of several plants to drought and salinity. In Olea europaea a mannitol transport system (OeMaT1) was previously characterised as a key player in plant response to salinity. In the present study, heterotrophic sink models, such as olive cell suspensions and fruit tissues, and source leaves were used for analytical, biochemical and molecular studies. The kinetic parameters of mannitol dehydrogenase (MTD) determined in mannitol-growing cells, at 25 °C and pH 9.0, were as follows: Km, 54.5 mM mannitol and Vmax, 0.47 Όmol h-1 mg-1 protein. The corresponding cDNA was cloned and named OeMTD1. OeMTD1 expression was correlated with MTD activity, OeMaT1 expression and carrier-mediated mannitol transport, in mannitol- and sucrose-growing cells. Furthermore, sucrosegrowing cells displayed only residual OeMTD activity, even though high levels of OeMTD1 transcription were observed. There is evidence OeMTD is regulated at both transcriptional and post-transcriptional levels. MTD activity and OeMTD1 expression were repressed after Na+, K+ and PEG treatments, both in mannitol- and sucrose-growing cells. In contrast, salt and drought significantly increased mannitol transport activity and OeMaT1 expression. Altogether, these studies support that olive tree copes with salinity and drought by coordinating mannitol transport with intracellular metabolism.This work was supported by the Portuguese Foundation for Science and Technology (FCT) (research project ref. PTDC/AGR-ALI/100636/2008; to A. Conde, grant ref. SFRH/BD/47699/2008; to C. Conde, grant ref. SFRH/BPD/34998/2007; to P. Silvagrant ref. SFRH/BD/13460/2003)

    Metabolomics demonstrates divergent responses of two Eucalyptus species to water stress

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    Past studies of water stress in Eucalyptus spp. generally highlighted the role of fewer than five “important” metabolites, whereas recent metabolomic studies on other genera have shown tens of compounds are affected. There are currently no metabolite profiling data for responses of stress-tolerant species to water stress. We used GC–MS metabolite profiling to examine the response of leaf metabolites to a long (2 month) and severe (ιpredawn < −2 MPa) water stress in two species of the perennial tree genus Eucalyptus (the mesic Eucalyptus pauciflora and the semi-arid Eucalyptus dumosa). Polar metabolites in leaves were analysed by GC–MS and inorganic ions by capillary electrophoresis. Pressure–volume curves and metabolite measurements showed that water stress led to more negative osmotic potential and increased total osmotically active solutes in leaves of both species. Water stress affected around 30–40% of measured metabolites in E. dumosa and 10–15% in E. pauciflora. There were many metabolites that were affected in E. dumosa but not E. pauciflora, and some that had opposite responses in the two species. For example, in E. dumosa there were increases in five acyclic sugar alcohols and four low-abundance carbohydrates that were unaffected by water stress in E. pauciflora. Re-watering increased osmotic potential and decreased total osmotically active solutes in E. pauciflora, whereas in E. dumosa re-watering led to further decreases in osmotic potential and increases in total osmotically active solutes. This experiment has added several extra dimensions to previous targeted analyses of water stress responses in Eucalyptus, and highlights that even species that are closely related (e.g. congeners) may respond differently to water stress and re-waterin

    Success evaluation factors in construction project management : some evidence from medium and large portuguese companies

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    The construction industry plays a very important role in the Portuguese economy. In 2009, it was among the top five economic sectors, representing 13% of total employment. Nevertheless, project failures are still frequent mainly due to inadequate management practices and to the intrinsic characteristics of projects of the construction industry. Even though Portuguese construction has improved in recent years, cost and schedule overruns, low productivity and final product quality problems are still common. In this context, project management is a crucial tool for improving construction operations and for the overall success of projects. The aim of this article is to contribute to the discussion on success evaluation factors in a field where little has been written – the construction industry. Through a survey of 40 medium and large Portuguese companies several factors were identified which are currently considered in the evaluation of project success, as found in the literature review. The results show that the traditional factors, often referred to as the “Atkinson elements triangle” (cost, time and quality), are still the most relevant for evaluating the success of a project, but others, such as customer involvement and acceptance, have gained importance in recent years
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