Random matrix models for phase diagrams

in Reports on Progress in Physics (2011), 74

We describe a random matrix approach that can provide generic and readily soluble mean-field descriptions of the phase diagram for a variety of systems ranging from QCD to high-T_c materials. Instead of ... [more ▼]

We describe a random matrix approach that can provide generic and readily soluble mean-field descriptions of the phase diagram for a variety of systems ranging from QCD to high-T_c materials. Instead of working from specific models, phase diagrams are constructed by averaging over the ensemble of theories that possesses the relevant symmetries of the problem. Although approximate in nature, this approach has a number of advantages. First, it can be useful in distinguishing generic features from model-dependent details. Second, it can help in understanding the `minimal' number of symmetry constraints required to reproduce specific phase structures. Third, the robustness of predictions can be checked with respect to variations in the detailed description of the interactions. Finally, near critical points, random matrix models bear strong similarities to Ginsburg-Landau theories with the advantage of additional constraints inherited from the symmetries of the underlying interaction. These constraints can be helpful in ruling out certain topologies in the phase diagram. In this Key Issue, we illustrate the basic structure of random matrix models, discuss their strengths and weaknesses, and consider the kinds of system to which they can be applied. [less ▲]

Random mutagenesis defines a domain of Theiler's virus leader protein which is essential for antagonism of nucleocytoplasmic trafficking and of cytokine gene expression

in Journal of Virology (2009), 83(21), 223-232

Random subwindows and extremely randomized trees for image classification in cell biology

in BMC Cell Biology (2007), 8(Suppl. 1),

Background: With the improvements in biosensors and high-throughput image acquisition technologies, life science laboratories are able to perform an increasing number of experiments that involve the ... [more ▼]

Background: With the improvements in biosensors and high-throughput image acquisition technologies, life science laboratories are able to perform an increasing number of experiments that involve the generation of a large amount of images at different imaging modalities/scales. It stresses the need for computer vision methods that automate image classification tasks. Results: We illustrate the potential of our image classification method in cell biology by evaluating it on four datasets of images related to protein distributions or subcellular localizations, and red-blood cell shapes. Accuracy results are quite good without any specific pre-processing neither domain knowledge incorporation. The method is implemented in Java and available upon request for evaluation and research purpose. Conclusion: Our method is directly applicable to any image classification problems. We foresee the use of this automatic approach as a baseline method and first try on various biological image classification problems. [less ▲]

Random Subwindows and Randomized Trees for Image Retrieval, Classification, and Annotation

Poster (2007, July 22)

The random-incidence scattering coefficient of infinite periodic surfaces with rectangular and sine-shaped roughness profiles

Conference (2011, July 01)

A randomised double blinded placebo controlled study of spironolactone as adjunct to conventional congestive heart failure treatment in dogs: clinical, biochemical and neurohormonal parameters

in 16th ECVIM Meeting - Amsterdam - Nederland - Septembre 2006 (2006, September)

A randomised placebo controlled 12 week trial of budesonide and prednisolone in rheumatoid arthritis

in Annals of the Rheumatic Diseases (2004), 63(6), 688-695

Objectives: To compare budesonide, a locally acting glucocorticoid with minimal systemic exposure, with conventional glucocorticoid treatment and placebo in rheumatoid arthritis. Methods: A double blind ... [more ▼]

Objectives: To compare budesonide, a locally acting glucocorticoid with minimal systemic exposure, with conventional glucocorticoid treatment and placebo in rheumatoid arthritis. Methods: A double blind, randomised, controlled trial over 12 weeks in 143 patients with active rheumatoid arthritis, comparing budesonide 3 mg daily, budesonide 9 mg daily, prednisolone 7.5 mg daily, and placebo. Particular attention was paid to the pattern of clinical response and to changes in the four week period following discontinuation of treatment. Results: There were improvements in tender joint count and swollen joint count on budesonide 9 mg compared with placebo (28% for tender and 34% for swollen joint counts, p< 0.05). Prednisolone 7.5 mg gave similar results, while budesonide 3 mg was less effective. ACR20 response criteria were met by 25% of patients on placebo, 22% on budesonide 3 mg, 42% on budesonide 9 mg, and 56% on prednisolone 7.5 mg. A rapid and significant reduction in symptoms and signs in response to budesonide 9 mg and prednisolone 7.5 mg was evident by two weeks and maximal at eight weeks. There was no evidence that budesonide provided a different pattern of symptom control from prednisolone, or that symptoms became worse than placebo treatment levels after discontinuation of glucocorticoid treatment. Adverse effects attributable to glucocorticoids were equally common in all groups. Conclusions: The symptomatic benefits of budesonide 9 mg and prednisolone 7.5 mg are achieved within a short time of initiating treatment, are maintained for three months, and are not associated with any rebound in symptoms after stopping treatment. [less ▲]

A randomised, double-blinded, placebo-controlled, parallel study of vitamin D3 supplementation with different schemes based on multiples of 25,000 IU doses

in International Journal of Endocrinology (in press)

Vitamin D (VTD) treatment is recommended in patients presenting different causes of diseases. To treat these patients, physicians rely on the different available pharmaceutical forms present in their ... [more ▼]

Vitamin D (VTD) treatment is recommended in patients presenting different causes of diseases. To treat these patients, physicians rely on the different available pharmaceutical forms present in their country. Unfortunately, even in a given country, there is no consensus on the best way to treat the patients. In Belgium, VTD is mostly prescribed as ampoules containing 25,000 IU of VTD. In this randomised controlled study, we evaluated whether four therapeutic schemes using multiples of 25,000 IU of VTD according to basal vitamin D concentration were able to increase or maintain the 25(OH)D serum level above 30 ng/mL. We randomized 175 subjects who received the drug () or placebo (). Total duration of the study was 12 weeks. Doses ranged from 4167 to 1667 IU/day. Blood sampling was performed at baseline and each 4 visits. In the treated (placebo) subjects, mean 25(OH)D serum concentration was 18.7 (19.1) ng/mL at baseline and 31.5 (20.7) ng/mL at w-12. At the end of the study, 57.1% of the subjects treated with VTD presented 25(OH)D serum concentration ≥30 ng/mL, whereas 94.3% were ≥20 ng/mL. In conclusion, the doses administered were safe and increased or maintained the 25(OH)D concentration ≥20 ng/mL. However, concentrations ≥30 ng/mL were only achieved in 57.1% of the subjects. [less ▲]

Randomized controlled study of the influence of two low estrogen dose oral contraceptives containing gestodene or desogestrel on carbohydrate metabolism.

in Contraception (2002), 66(6), 411-5

This study compared the impact on carbohydrate metabolism of two combinedoral contraceptives (COCs). This open-label, single-center trial enrolled participants for a total of 15 cycles. Thirty-six women ... [more ▼]

This study compared the impact on carbohydrate metabolism of two combinedoral contraceptives (COCs). This open-label, single-center trial enrolled participants for a total of 15 cycles. Thirty-six women were randomized to receive either 20 microg ethinyl estradiol (EE) and 75 microg gestodene (GSD) or 20 microg ethinyl estradiol and 150 microg desogestrel (DSG) daily for 21 days out of 28. A glucose tolerance test was performed at baseline and cycles 6 and 13. The area under the curve (AUC) for glucose increased in both study groups. The change was statistically significant (p = 0.036) for the 20 EE/75 GSD group at cycle 6 versus baseline. Fasting blood glucose at cycle 13 was significantly (p < 0.01) higher for both treatment groups compared to baseline. No changes were found for fasting insulin and fasting C-peptide levels or for the AUCs of insulin or C-peptide. Both regimens were well tolerated. Gestodene and desogestrel in combination with 20-microg ethinyl estradiol induce similar changes in carbohydrate metabolism which are smaller than those described earlier for COCs containing higher estrogen doses or more androgenic progestins such as levonorgestrel. [less ▲]

A randomized double-blind placebo-controlled trial of thioctic acid in migraine prophylaxis

in Headache (2007), 47(1), 52-57

BACKGROUND: Impaired mitochondrial phosphorylation potential may play a role in migraine pathogenesis. Metabolic enhancers, such as riboflavin or coenzyme Q, are effective in migraine prophylaxis and ... [more ▼]

BACKGROUND: Impaired mitochondrial phosphorylation potential may play a role in migraine pathogenesis. Metabolic enhancers, such as riboflavin or coenzyme Q, are effective in migraine prophylaxis and quasi-devoid of adverse effects. Thioctic acid (-lipoic acid) is another substance known to enhance energy metabolism in mitochondria and to be beneficial in diabetic neuropathy. OBJECTIVE: After an open pilot study suggesting its therapeutic antimigraine potentials, we embarked therefore in a randomized controlled trial of thioctic acid (Thioctacid) in migraine prophylaxis steered by the Belgian Headache Society. METHODS: Five Belgian centers recruited 54 migraineurs (43 migraine without aura, 11 with aura; mean age 38 +/- 8 years; 7 males). After a 1-month single-blinded run-in period, 44 patients received either placebo (n = 18) or thioctic acid 600 mg p.o./day (n = 26) for 3 months. RESULTS: Statistical analysis was carried out on an intention-to-treat basis. Monthly attack frequency tended to be reduced between run-in and the 3rd month of treatment in the thioctic acid group compared to placebo (P= .06). The proportion of 50% responders was not significantly different between thioctic acid (30.8%) and placebo (27.8%). Within-group analyses showed a significant reduction of attack frequency (P= .005), headache days (P= .009), and headache severity (P= .03) in patients treated with thioctic acid for 3 months, while these outcome measures remained unchanged in the placebo group. No adverse effects were reported. For logistical reasons this trial was interrupted before the planned 80 patients were enrolled. CONCLUSION: Albeit underpowered, this study tends to indicate that thioctic acid may be beneficial in migraine prophylaxis. Before any firm conclusion can be drawn, however, a large multicenter trial is necessary. [less ▲]