As time goes by

A rather simple and non-technical exposition of our new approach to {\em Time, Quantum Physics, Black-Hole dynamics}, and {\em Cosmology}, based on non-critical string theory, is provided. A new fundamental principle, the {\em Procrustean Principle}, that catches the essence of our approach is postulated: the low-energy world is {\em unavoidably} an ``open" system due to the spontaneous truncation of the {\em delocalized, topological} string modes in continuous interaction with the low-lying-{\em localized} string modes. The origin of space-time, the expansion of the Universe, the entropy increase and accompanied irreversibility of time, as well as the collapse of the wavefunction are all very neatly tied together. Possible observable consequences include: quantum relaxation with time of the Universal, fundamental constants, like the velocity of light $c$ and the Planck constant $\hbar$ decreasing towards their asymptotic values, and the cosmological constant $\Lambda_C$ diminishing towards zero; possible violation of {\em CPT} invariance in the $K^0-\bar K^0$ system, possible apparent non-conservation of angular momentum, and possible loss of quantum coherence in SQUID-type experiments.Comment: CERN-TH.7260/94, 84 pages Latex (no figures

Meneco, a Topology-Based Gap-Filling Tool Applicable to Degraded Genome-Wide Metabolic Networks

International audienceIncreasing amounts of sequence data are becoming available for a wide range of non-model organisms. Investigating and modelling the metabolic behaviour of those organisms is highly relevant to understand their biology and ecology. As sequences are often incomplete and poorly annotated, draft networks of their metabolism largely suffer from incompleteness. Appropriate gap-filling methods to identify and add missing reactions are therefore required to address this issue. However, current tools rely on phenotypic or taxonomic information, or are very sensitive to the stoichiometric balance of metabolic reactions, especially concerning the co-factors. This type of information is often not available or at least prone to errors for newly-explored organisms. Here we introduce Meneco, a tool dedicated to the topological gap-filling of genome-scale draft metabolic networks. Meneco reformulates gap-filling as a qualitative combinatorial optimization problem, omitting constraints raised by the stoichiometry of a metabolic network considered in other methods, and solves this problem using Answer Set Programming. Run on several artificial test sets gathering 10,800 degraded Escherichia coli networks Meneco was able to efficiently identify essential reactions missing in networks at high degradation rates, outperforming the stoichiometry-based tools in scalability. To demonstrate the utility of Meneco we applied it to two case studies. Its application to recent metabolic networks reconstructed for the brown algal model Ectocarpus siliculosus and an associated bacterium Candidatus Phaeomarinobacter ectocarpi revealed several candidate metabolic pathways for algal-bacterial interactions. Then Meneco was used to reconstruct, from transcriptomic and metabolomic data, the first metabolic network for the microalga Euglena mutabilis. These two case studies show that Meneco is a versatile tool to complete draft genome-scale metabolic networks produced from heterogeneous data, and to suggest relevant reactions that explain the metabolic capacity of a biological system

Assessment of splenic function

Hyposplenic patients are at risk of overwhelming post-splenectomy infection (OPSI), which carries mortality of up to 70%. Therefore, preventive measures are warranted. However, patients with diminished splenic function are difficult to identify. In this review we discuss immunological, haematological and scintigraphic parameters that can be used to measure splenic function. IgM memory B cells are a potential parameter for assessing splenic function; however, more studies are necessary for its validation. Detection of Howell–Jolly bodies does not reflect splenic function accurately, whereas determining the percentage of pitted erythrocytes is a well-evaluated method and seems a good first-line investigation for assessing splenic function. When assessing spleen function, 99mTc-labelled, heat-altered, autologous erythrocyte scintigraphy with multimodality single photon emission computed tomography (SPECT)-CT technology is the best approach, as all facets of splenic function are evaluated. In conclusion, although scintigraphic methods are most reliable, they are not suitable for screening large populations. We therefore recommend using the percentage of pitted erythrocytes, albeit suboptimal, as a first-line investigation and subsequently confirming abnormal readings by means of scintigraphy. More studies evaluating the value of potentially new markers are needed

Efficiency and productivity assessment of public hospitals in Greece during the crisis period 2009–2012

Abstract Background This study is an initial effort to examine the dynamics of efficiency and productivity in Greek public hospitals during the first phase of the crisis 2009–2012. Data were collected by the Ministry of Health after several quality controls ensuring comparability and validity of hospital inputs and outputs. Productivity is estimated using the Malmquist Indicator, decomposing the estimated values into efficiency and technological change. Methods Hospital efficiency and productivity growth are calculated by bootstrapping the non-parametric Malmquist analysis. The advantage of this method is the estimation efficiency and productivity through the corresponding confidence intervals. Additionally, a Random-effects Tobit model is explored to investigate the impact of contextual factors on the magnitude of efficiency. Results Findings reveal substantial variations in hospital productivity over the period from 2009 to 2012. The economic crisis of 2009 had a negative impact in productivity. The average Malmquist Productivity Indicator (MPI) score is 0.72 with unity signifying stable production. Approximately 91% of the hospitals score lower than unity. Substantial increase is observed between 2010 and 2011, as indicated by the average MPI score which fluctuates to 1.52. Moreover, technology change scored more than unity in more than 75% of hospitals. The last period (2011–2012) has shown stabilization in the expansionary process of productivity. The main factors contributing to overall productivity gains are increases in occupancy rates, type and size of the hospital. Conclusions This paper attempts to offer insights in efficiency and productivity growth for public hospitals in Greece. The results suggest that the average hospital experienced substantial productivity growth between 2009 and 2012 as indicated by variations in MPI. Almost all of the productivity increase was due to technology change which could be explained by the concurrent managerial and financing healthcare reforms. Hospitals operating under decreasing returns to scale could achieve higher efficiency rates by reducing their capacity. However, certain social objectives should also be considered. Emphasis perhaps should be placed in utilizing and advancing managerial and organizational reforms, so that the benefits of technological improvements will have a continuing positive impact in the future