The Scaling Window of the 2-SAT Transition

We consider the random 2-satisfiability problem, in which each instance is a formula that is the conjunction of m clauses of the form (x or y), chosen uniformly at random from among all 2-clauses on n Boolean variables and their negations. As m and n tend to infinity in the ratio m/n --> alpha, the problem is known to have a phase transition at alpha_c = 1, below which the probability that the formula is satisfiable tends to one and above which it tends to zero. We determine the finite-size scaling about this transition, namely the scaling of the maximal window W(n,delta) = (alpha_-(n,delta),alpha_+(n,delta)) such that the probability of satisfiability is greater than 1-delta for alpha < alpha_- and is less than delta for alpha > alpha_+. We show that W(n,delta)=(1-Theta(n^{-1/3}),1+Theta(n^{-1/3})), where the constants implicit in Theta depend on delta. We also determine the rates at which the probability of satisfiability approaches one and zero at the boundaries of the window. Namely, for m=(1+epsilon)n, where epsilon may depend on n as long as |epsilon| is sufficiently small and |epsilon|*n^(1/3) is sufficiently large, we show that the probability of satisfiability decays like exp(-Theta(n*epsilon^3)) above the window, and goes to one like 1-Theta(1/(n*|epsilon|^3)) below the window. We prove these results by defining an order parameter for the transition and establishing its scaling behavior in n both inside and outside the window. Using this order parameter, we prove that the 2-SAT phase transition is continuous with an order parameter critical exponent of 1. We also determine the values of two other critical exponents, showing that the exponents of 2-SAT are identical to those of the random graph.Comment: 57 pages. This version updates some reference

Optimized Handover and Resource Management: An 802.21 Based Scheme to Optimize Handover and Resource Management in Hybrid Satellite-Terrestrial Networks

International audienceSatellite communications can provide fourth generation (4G) networks with large-scale coverage. However, their integration to 4G is challenging because satellite networks have not been designed with handover in mind. The setup of satellite links takes time, and so, handovers must be anticipated long before. This paper proposes a generic scheme based on the Institute of Electrical and Electronics Engineers 802.21 standard to optimize handover and resource management in hybrid satellite-terrestrial networks. Our solution, namely optimized handover and resource management (OHRM), uses the terrestrial interface to prepare handover, which greatly speeds up the establishment of the satellite link. We propose two mechanisms to minimize the waste of bandwidth due to wrong handover predictions. First, we leverage the support of 802.21 in the terrestrial access network to shorten the path of the signaling messages towards the satellite resource manager. Second, we cancel the restoration of the satellite resources when the terrestrial link rolls back. We use OHRM to interconnect a digital video broadcasting and a wireless 4G terrestrial network. However for the simulation tool, we use a WiMAX as the terrestrial technology to illustrate the schemes. The simulation results show that OHRM minimizes the handover delay and the signaling overhead in the terrestrial and satellite networks

Phototesting and photoprotection in LE

Photosensitivity and induction of skin lesions following UV radiation is a common problem of patients with cutaneous and systemic forms of lupus erythematosus. The detrimental effect of UV radiation to patients with lupus erythematosus was already recognized in the last century. Skin lesions can now be provoked under standardized conditions allowing the diagnosis and classification of patients with photosensitive disorders. The aim of this review is to give an overview on the history, test procedure and test results in patients with lupus erythematosus

Imaging-in-flow: digital holographic microscopy as a novel tool to detect and classify nanoplanktonic organisms

Traditional taxonomic identification of planktonic organisms is based on light microscopy, which is both time-consuming and tedious. In response, novel ways of automated (machine) identification, such as flow cytometry, have been investigated over the last two decades. To improve the taxonomic resolution of particle analysis, recent developments have focused on "imaging-in-flow," i.e., the ability to acquire microscopic images of planktonic cells in a flow-through mode. Imaging-in-flow systems are traditionally based on classical brightfield microscopy and are faced with a number of issues that decrease the classification performance and accuracy (e. g., projection variance of cells, migration of cells out of the focus plane). Here, we demonstrate that a combination of digital holographic microscopy (DHM) with imaging-in-flow can improve the detection and classification of planktonic organisms. In addition to light intensity information, DHM provides quantitative phase information, which generates an additional and independent set of features that can be used in classification algorithms. Moreover, the capability of digitally refocusing greatly increases the depth of field, enables a more accurate focusing of cells, and reduces the effects of position variance. Nanoplanktonic organisms similar in shape were successfully classified from images captured with an off-axis DHM with partial coherence. Textural features based on DHM phase information proved more efficient in separating the three tested phytoplankton species compared with shape-based features or textural features based on light intensity. An overall classification score of 92.4% demonstrates the potential of holographic-based imaging-in-flow for similar looking organisms in the nanoplankton range

Signal level comparison between TerraSAR-X and COSMO-SkyMed SAR Sensors

International audienceSoil and vegetation biophysical parameter retrieval using synthetic-aperture-radar images requires radiometrically well-calibrated sensors. In this letter, a comparison of signal levels between TerraSAR-X (TSX) and the COSMO-SkyMed (CSK) constellation (CSK1, CSK2, CSK3, and CSK4) was carried out in order to analyze the ability to use jointly all current X-band sensors. The analysis of the X-band signal over forest stands showed a stable signal (variation lower than 1 dB) over time for each of the studied sensors, but a significant difference was observed between the different X-band sensors. Differences between radar signals were higher in HH than in HV polarization. TSX and CSK4 showed similar backscatter signals, with signal level differences of 0.6 dB in HH and 1.4 dB in HV. The CSK3 signal was observed to be lower than those from TSX and CSK4 by about 2.1 dB and 1.5 dB in HH against 3.2 dB and 1.8 dB in HV, respectively. Moreover, CSK2 and CSK1 which showed slightly different backscatter signals (within 1.1 dB in HH and 1.9 dB in HV) had signal levels lower than those obtained from TSX (2.2-3.3 dB in HH and 3.2-5.1 dB in HV for about 29° incidence angle). These results show that it is currently difficult to use jointly the available X-band satellites (CSK and TSX) for estimating the biophysical parameters of soil or vegetation. This is due to the significant difference in the radar signal level between some of the analyzed satellites, which will cause a high overor underestimation of biophysical parameters

Qualité microbiologique des fromages artisanaux fabriqués au lait cru en Région wallonne

Microbiological quality of craft raw milk cheeses produced in Wallonia. The main objective of this study was to evaluatethe bacteriological quality of raw milk cheeses produced in the southern part of Belgium (Wallonia) and to compare withsamples coming from other European countries. Results from bacteriological analyses of 153 cheese samples have beencompared with regard to food microbial standards (92/46 EC Directive). It can be concluded from this work that 69% of thesamples may be considered as acceptable, while 31% showed coliforms and Staplylococcus aureus counts exceeding thestandard values. As far as pathogens were concerned, 0.7% and 7.2% of the samples have were found unsatifactory with thecriteria related to Salmonella and Listeria monocytogenes, respectively. Enterobacteriaceae contamination has also beenevaluated and demonstrated an average log count of about 3.78 cfu/g. Cheeses produced from ewe milk showed anoutstanding microbiological quality since all samples turned out to be acceptable regarding the S. aureus counts and devoidof Salmonella and L. monocytogenes contamination. Although no seasonal effect on the bacteriological quality could beobserved, the microbial quality decreased after the production stage, i.e. mainly during the storage and the distribution.Cheese made by small producers seems to be better than those originating from industrial enterprises. By comparing theseresults with those obtained on cheese samples produced in some other European countries, it appears that the mean qualitylevel of Walloon raw milk cheeses is quite satifactory

Repeated coronary artery occlusions during routine balloon angioplasty do not induce myocardial preconditioning in humans

AbstractObjectives.The purpose of the present study was to assess whether brief, repeated coronary artery occlusions during balloon angioplasty induce a myocardial ischemic protective effect.Background.In animals, brief coronary artery occlusions preceding a more prolonged occlusion result in reduced infarct size. Whether myocardial protection against ischemia could also occur in humans during angioplasty remains controversial.Methods.Thirteen patients with a proximal left anterior descending coronary artery stenosis with no angiographic collateral circulation underwent percutaneous transluminal coronary artery balloon angioplasty. Three 120-s balloon inflations separated by a 5-min equilibrium period were performed. For each inflation, intracoronary ST segment modifications, septal wall thickening (M-mode echocardiography), left ventricular pressures and time derivatives were measured at baseline and at 30, 60 a d 90 s after balloon inflation and 120 s after balloon deflation.Results.Intracoronary electrocardiographic analysis showed that the time course of the maximal ST segment elevation was identical at each inflation, as were wall motion changes assessed by the decrease in septal wall thickening. For the first and last inflations, peak positive dP/dt decreased significantly by 13 ± 9% (mean ± SD) and 14 ± 13%, whereas peak negative dP/dt increased by 23 ± 15% and 22 ± 10%, respectively (all p < 0.01 from baseline values). The relaxation time constant, tau, was altered similarity during the different inflations, from 44 ± 6 to 74 ± 13 ms and from 57 ± 13 to 77 ± 13 ms (all p < 0.001) for the first and last inflations, respectively. Left ventricular endiastolic pressure increased to the same level after each inflation. In contrast to other hemodynamic variables, tau and left ventricular end-diastolic pressure did not return to baseline values in between the inflations, which may be due to myocardial stunning.Conclusions.In patients with proximal left anterior descending coronary artery stenosis and no evidence of collateral circulation, brief periods of ischemia, such as those used during routine coronary balloon angioplasty, do not provide any protection against myocardial ischemia

Low percentage of clinically relevant pistachio nut and mango co-sensitisation in cashew nut sensitised children

Background: Cashew nut, pistachio nut and mango belong to the Anacardiaceae family and are botanically related. Therefore, cashew nut sensitised children are frequently advised to eliminate cashew nuts and pistachio nuts from their diet. The ‘Improvement of Diagnostic mEthods for ALlergy assessment (IDEAL trial number NTR3572) study showed that cashew nut sensitised children were co-sensitised to pistachio nut in 98% of cases and to mango in 21% of cases. The aim of this follow-up study to IDEAL is to assess the clinical relevance of co-sensitisation to pistachio nut and mango in cashew nut sensitised children. Methods: Children were recruited from the study: ‘Improvement of Diagnostic mEthods for ALlergy assessment (IDEAL trial number NTR3572). Inclusion criterion for the IDEAL study was sensitization to cashew nut as demonstrated by either SPT or sIgE, and a clinical history of reactions to cashew nuts or no previous (known) exposure. Sensitized children who were tolerant to cashew nuts were excluded. Inclusion criterion for this IDEAL follow-up study was co-sensitization to pistachio nut, regardless the result of the DBPCFC with cashew nut. In this follow-up study a double-blind placebo-controlled food challenge with pistachio nut and an open food challenge with mango were performed. Results: Twenty-nine children (mean age of 11.6 years, 62% male) were included. Pistachio nut sensitisation was clinically relevant in only 34% of cashew-sensitised children and only 31% of cashew challenge positive children. None of the children was challenge positive to mango. Conclusion: Although co-sensitisation between cashew nut and pistachio nut was observed in 98%, pistachio nut sensitisation was only clinically relevant in 34% of the children. Therefore, a challenge test with pistachio nut is recommended in children with cashew nut and pistachio nut sensitisation