High-spatial-resolution passive microwave sounding systems

During this period the emphasis was on the following: (1) further design, construction, and testing of the improved 54-GHz portion of the 54-118 GHz microwave temperature sounder (MTS) aircraft radiometer system in preparation for ER-2 observations in July 1991; and (2) final analysis and documentation of procedures for detecting and analyzing thermal waves in our 118-GHz MTS imagery. In addition, we have new unpublished measurements of dry-air attenuation at frequencies of 54 to 66 GHz and over a temperature range of 280K to 326K; these measurements should enable us to improve further our atmospheric transmittance models. It was further noted that the proposed SSMIS conical-scanning microwave spectrometer on the military DMSP Block 5D-3 spacecraft designed to measure stratospheric and mesospheric temperature profiles will be observing the Zeeman-split oxygen lines with sufficient spectral resolution that the changing Doppler shifts with view angle will substantially degrade the potential system performance unless remedied; this was briefly studied and documented

Speeding up Cylindrical Algebraic Decomposition by Gr\"obner Bases

Gr\"obner Bases and Cylindrical Algebraic Decomposition are generally thought of as two, rather different, methods of looking at systems of equations and, in the case of Cylindrical Algebraic Decomposition, inequalities. However, even for a mixed system of equalities and inequalities, it is possible to apply Gr\"obner bases to the (conjoined) equalities before invoking CAD. We see that this is, quite often but not always, a beneficial preconditioning of the CAD problem. It is also possible to precondition the (conjoined) inequalities with respect to the equalities, and this can also be useful in many cases.Comment: To appear in Proc. CICM 2012, LNCS 736

Adiabatic and non-adiabatic phonon dispersion in a Wannier function approach

We develop a first-principles scheme to calculate adiabatic and non-adiabatic phonon frequencies in the full Brillouin zone. The method relies on the variational properties of a force-constants functional with respect to the first-order perturbation of the electronic charge density and on the localization of the deformation potential in the Wannier function basis. This allows for calculation of phonon dispersion curves free from convergence issues related to Brillouin zone sampling. In addition our approach justify the use of the static screened potential in the calculation of the phonon linewidth due to decay in electron-hole pairs. We apply the method to the calculation of the phonon dispersion and electron-phonon coupling in MgB$_2$ and CaC$_6$. In both compounds we demonstrate the occurrence of several Kohn anomalies, absent in previous calculations, that are manifest only after careful electron and phonon momentum integration. In MgB$_2$, the presence of Kohn anomalies on the E$_{2g}$ branches improves the agreement with measured phonon spectra and affects the position of the main peak in the Eliashberg function. In CaC$_6$ we show that the non-adiabatic effects on in-plane carbon vibrations are not localized at zone center but are sizable throughout the full Brillouin zone. Our method opens new perspectives in large-scale first-principles calculations of dynamical properties and electron-phonon interaction.Comment: 18 pages, 8 figure

A new method based on noise counting to monitor the frontend electronics of the LHCb muon detector

A new method has been developed to check the correct behaviour of the frontend electronics of the LHCb muon detector. This method is based on the measurement of the electronic noise rate at different thresholds of the frontend discriminator. The method was used to choose the optimal discriminator thresholds. A procedure based on this method was implemented in the detector control system and allowed the detection of a small percentage of frontend channels which had deteriorated. A Monte Carlo simulation has been performed to check the validity of the method

Menopausal Status Dependence of the Timing of Breast Cancer Recurrence after Surgical Removal of the Primary Tumour

Introduction: Information on the metastasis process in breast cancer patients undergoing primary tumour removal may be extracted from an analysis of the timing of clinical recurrence. Methods: The hazard rate for local-regional and/or distant recurrence as the first event during the first 4 years after surgery was studied in 1173 patients undergoing mastectomy alone as primary treatment for operable breast cancer. Subset analyses were performed according to tumour size, axillary nodal status and menopausal status. Results: A sharp two-peaked hazard function was observed for node-positive pre-menopausal patients, whereas results from node-positive post-menopausal women always displayed a single broad peak. The first narrow peak among pre-menopausal women showed a very steep rise to a maximum about 8–10 months after mastectomy. The second peak was considerably broader, reaching its maximum at 28–30 months. Post-menopausal patients displayed a wide, nearly symmetrical peak with maximum risk at about 18–20 months. Peaks displayed increasing height with increasing axillary lymph node involvement. No multi-peaked pattern was evident for either pre-menopausal or post-menopausal node-negative patients; however, this finding should be considered cautiously because of the limited number of events. Tumour size influenced recurrence risk but not its timing. Findings resulting from the different subsets of patients were remarkably coherent and each observed peak maintained the same position on the time axis in all analysed subsets. Conclusions: The risk of early recurrence for node positive patients is dependent on menopausal status. The amount of axillary nodal involvement and the tumour size modulate the risk value at any given time. For pre-menopausal node-positive patients, the abrupt increase of the first narrow peak of the recurrence risk suggests a triggering event that synchronises early risk. We suggest that this event is the surgical removal of the primary tumour. The later, broader, more symmetrical risk peaks indicate that some features of the corresponding metastatic development may present stochastic traits. A metastasis development model incorporating tumour dormancy in specific micro-metastatic phases, stochastic transitions between them and sudden acceleration of the metastatic process by surgery can explain these risk dynamics

Effect of a multidisciplinary treatment program on eating behavior in overweight and obese preschool children

Background: The effects of multidisciplinary treatment programs on eating behavior in overweight preschoolaged children are largely unknown. We evaluated a multidisciplinary intervention program on eating behavior in 3- to 5-year-old overweight children, comparing them with children given standard treatment. We also assessed the parental eating behavior changes and investigated associations between parents and children. Methods: We randomized 75 children to a multidisciplinary intervention or to a standard care program. During a 16-week period, children and parents in the multidisciplinary group were given dietary advice, physical activity sessions and, for parents only, psychological counseling. Children and parents in the standard group visited a pediatrician 3 times and were given information on a healthy lifestyle. At baseline, after 16 weeks, and after 12 months, children were measured and parents completed the Dutch Child Eating Behavior Questionnaire (DEBQ-C) for their children and the DEBQ for themselves. Results: At the three time points, 70 (93.3%), 57 (91.9%), and 42 (73.7%) DEBQ-Cs were analyzed. We found no differences in the changes in eating behavior between the two groups over time. In both groups, there was a significant increase in restrained eating behavior present at 16 weeks, however, this was no longer present at 12 months. We found no associations between changes in eating behavior between the children and their parents. Conclusions: A multidisciplinary obesity intervention program in preschool-aged children induced more restrained eating behavior between baseline and 16 weeks. However, there was no difference with the children in the standard care group

Selection and characterization of a promoter for expression of single-copy recombinant genes in Gram-positive bacteria

BACKGROUND: In the past ten years there has been a growing interest in engineering Gram-positive bacteria for biotechnological applications, including vaccine delivery and production of recombinant proteins. Usually, bacteria are manipulated using plasmid expression vectors. The major limitation of this approach is due to the fact that recombinant plasmids are often lost from the bacterial culture upon removal of antibiotic selection. We have developed a genetic system based on suicide vectors on conjugative transposons allowing stable integration of recombinant DNA into the chromosome of transformable and non-transformable Gram-positive bacteria. RESULTS: The aim of this work was to select a strong chromosomal promoter from Streptococcus gordonii to improve this genetic system making it suitable for expression of single-copy recombinant genes. To achieve this task, a promoterless gene encoding a chloramphenicol acetyltransferase (cat), was randomly integrated into the S. gordonii chromosome and transformants were selected for chloramphenicol resistance. Three out of eighteen chloramphenicol resistant transformants selected exhibited 100% stability of the phenotype and only one of them, GP215, carried the cat gene integrated as a single copy. A DNA fragment of 600 base pairs exhibiting promoter activity was isolated from GP215 and sequenced. The 5' end of its corresponding mRNA was determined by primer extention analysis and the putative -10 and a -35 regions were identified. To study the possibility of using this promoter (PP) for single copy heterologous gene expression, we created transcriptional fusions of PP with genes encoding surface recombinant proteins in a vector capable of integrating into the conjugative transposon Tn916. Surface recombinant proteins whose expression was controlled by the PP promoter were detected in Tn916-containing strains of S. gordonii and Bacillus subtilis after single copy chromosomal integration of the recombinant insertion vectors into the resident Tn916. The surface recombinant protein synthesized under the control of PP was also detected in Enterococcus faecalis after conjugal transfer of a recombinant Tn916 containing the transcriptional fusion. CONCLUSION: We isolated and characterized a S. gordonii chromosomal promoter. We demonstrated that this promoter can be used to direct expression of heterologous genes in different Gram-positive bacteria, when integrated in a single copy into the chromosome

Magnetic breakdown in a normal-metal - superconductor proximity sandwich

We study the magnetic response of a clean normal-metal slab of finite thickness in proximity with a bulk superconductor. We determine its free energy and identify two (meta-)stable states, a diamagnetic one where the applied field is effectively screened, and a second state, where the field penetrates the normal-metal layer. We present a complete characterization of the first order transition between the two states which occurs at the breakdown field, including its spinodals, the jump in the magnetization, and the latent heat. The bistable regime terminates at a critical temperature above which the sharp transition is replaced by a continuous cross-over. We compare the theory with experiments on normal-superconducting cylinders.Comment: 7 pages Revtex, 3 Postscript figures, needs psfig.te

Freezing transition of the vortex liquid in anisotropic superconductors

We study the solid-liquid transition of a model of pancake vortices in laminar superconductors using a density functional theory of freezing. The physical properties of the system along the melting line are discussed in detail. We show that there is a very good agreement with experimental data in the shape and position of the first order transition in the phase diagram and in the magnitude and temperature dependence of the magnetic induction jump at the transition. We analyze the validity of the Lindemann melting criterion and the Hansen-Verlet freezing criterion. Both criteria are shown to be good to predict the phase diagram in the region where a first order phase transition is experimentally observed.Comment: 9 pages, 10 figure