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Bisimulation Relations Between Automata, Stochastic Differential Equations and Petri Nets
Mariken H.C. Everdij,Henk A.P. Blom
Electronic Proceedings in Theoretical Computer Science , 2010, DOI: 10.4204/eptcs.20.1
Abstract: Two formal stochastic models are said to be bisimilar if their solutions as a stochastic process are probabilistically equivalent. Bisimilarity between two stochastic model formalisms means that the strengths of one stochastic model formalism can be used by the other stochastic model formalism. The aim of this paper is to explain bisimilarity relations between stochastic hybrid automata, stochastic differential equations on hybrid space and stochastic hybrid Petri nets. These bisimilarity relations make it possible to combine the formal verification power of automata with the analysis power of stochastic differential equations and the compositional specification power of Petri nets. The relations and their combined strengths are illustrated for an air traffic example.
Neural Tube Defects, Folic Acid and Methylation
Apolline Imbard,Jean-Fran?ois Benoist,Henk J. Blom
International Journal of Environmental Research and Public Health , 2013, DOI: 10.3390/ijerph10094352
Abstract: Neural tube defects (NTDs) are common complex congenital malformations resulting from failure of the neural tube closure during embryogenesis. It is established that folic acid supplementation decreases the prevalence of NTDs, which has led to national public health policies regarding folic acid. To date, animal studies have not provided sufficient information to establish the metabolic and/or genomic mechanism(s) underlying human folic acid responsiveness in NTDs. However, several lines of evidence suggest that not only folates but also choline, B12 and methylation metabolisms are involved in NTDs. Decreased B12 vitamin and increased total choline or homocysteine in maternal blood have been shown to be associated with increased NTDs risk. Several polymorphisms of genes involved in these pathways have also been implicated in risk of development of NTDs. This raises the question whether supplementation with B12 vitamin, betaine or other methylation donors in addition to folic acid periconceptional supplementation will further reduce NTD risk. The objective of this article is to review the role of methylation metabolism in the onset of neural tube defects.
Interacting Multiple Model-Feedback Particle Filter for Stochastic Hybrid Systems
Tao Yang,Henk A. P. Blom,Prashant G. Mehta
Mathematics , 2013,
Abstract: In this paper, a novel feedback control-based particle filter algorithm for the continuous-time stochastic hybrid system estimation problem is presented. This particle filter is referred to as the interacting multiple model-feedback particle filter (IMM-FPF), and is based on the recently developed feedback particle filter. The IMM-FPF is comprised of a series of parallel FPFs, one for each discrete mode, and an exact filter recursion for the mode association probability. The proposed IMM-FPF represents a generalization of the Kalmanfilter based IMM algorithm to the general nonlinear filtering problem. The remarkable conclusion of this paper is that the IMM-FPF algorithm retains the innovation error-based feedback structure even for the nonlinear problem. The interaction/merging process is also handled via a control-based approach. The theoretical results are illustrated with the aid of a numerical example problem for a maneuvering target tracking application.
Ovarian Cyst Fluid of Serous Ovarian Tumors Contains Large Quantities of the Brain Amino Acid N-acetylaspartate
Eva Kolwijck,Ron A. Wevers,Udo F. Engelke,Jannes Woudenberg,Johan Bulten,Henk J. Blom,Leon F. A. G. Massuger
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010293
Abstract: In humans, N-acetyl L-aspartate (NAA) has not been detected in other tissues than the brain. The physiological function of NAA is yet undefined. Recently, it has been suggested that NAA may function as a molecular water pump, responsible for the removal of large amounts of water from the human brain. Ovarian tumors typically present as large cystic masses with considerable fluid accumulation.
No Effect of Folic Acid Supplementation on Global DNA Methylation in Men and Women with Moderately Elevated Homocysteine
Audrey Y. Jung, Yvo Smulders, Petra Verhoef, Frans J. Kok, Henk Blom, Robert M. Kok, Ellen Kampman, Jane Durga
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024976
Abstract: A global loss of cytosine methylation in DNA has been implicated in a wide range of diseases. There is growing evidence that modifications in DNA methylation can be brought about by altering the intake of methyl donors such as folate. We examined whether long-term daily supplementation with 0.8 mg of folic acid would increase global DNA methylation compared with placebo in individuals with elevated plasma homocysteine. We also investigated if these effects were modified by MTHFR C677T genotype. Two hundred sixteen participants out of 818 subjects who had participated in a randomized double-blind placebo-controlled trial were selected, pre-stratified on MTHFR C677T genotype and matched on age and smoking status. They were allocated to receive either folic acid (0.8 mg/d; n = 105) or placebo treatment (n = 111) for three years. Peripheral blood leukocyte DNA methylation and serum and erythrocyte folate were assessed. Global DNA methylation was measured using liquid chromatography-tandem mass spectrometry and expressed as a percentage of 5-methylcytosines versus the total number of cytosine. There was no difference in global DNA methylation between those randomized to folic acid and those in the placebo group (difference = 0.008, 95%CI = ?0.05,0.07, P = 0.79). There was also no difference between treatment groups when we stratified for MTHFR C677T genotype (CC, n = 76; CT, n = 70; TT, n = 70), baseline erythrocyte folate status or baseline DNA methylation levels. In moderately hyperhomocysteinemic men and women, long-term folic acid supplementation does not increase global DNA methylation in peripheral blood leukocytes. ClinicalTrials.gov NCT00110604
User Experience of ColdZyme Mouth Spray against Common Cold in Competitive Athletes  [PDF]
Ulf Blom, Ida Nelson
Open Journal of Respiratory Diseases (OJRD) , 2018, DOI: 10.4236/ojrd.2018.82002
ColdZyme Mouth Spray (ColdZyme) is intended to reduce the probability of catching a cold and/or can help shorten the duration of a cold, if used at an early stage of the infection, by forming a barrier on the pharyngeal mucous membrane. The user experience of ColdZyme on naturally occurring common cold infections was evaluated in competitive athletes training professionally or on an amateur level. Thirteen athletes completed weekly electronic surveys on occurrence of common colds, cold severity and user experience over the course of 3 months. The 13 participants reported in total 15 cold incidents with an average duration of 7.4 days. The average cold severity was 31.2 on a visual-analogue scale (VAS) ranging from 0 (mildest possible cold) to 100 (worst possible cold). The overall user satisfaction with ColdZyme was high. 81% of the reported colds were experienced to be milder and/or shorter than usual. None of the participants reported “No effect”. Out of the participants who reported absence of a cold in the previous week, 69% reported a positive answer to the question if ColdZyme had prevented them from catching a cold in the previous week. Conclusion: The present study evaluated prevention and alleviation of naturally occurring common cold in athletes, and demonstrated that ColdZyme may be an easy and practical way for competitive athletes to prevent or reduce infections of the common cold virus and corresponding unwanted absence from training and competition. Due to the lack of a comparator group, a placebo effect cannot be excluded.
New Dark Matter Generation Mechanism and Its Implications for the Cosmological Background  [PDF]
Henk Defloor
Journal of High Energy Physics, Gravitation and Cosmology (JHEPGC) , 2017, DOI: 10.4236/jhepgc.2017.34058
Abstract: A new concept has been proposed and elaborated to account for recent observations deviating from ΛCDM and ΛWDM. Using an intermediate energy conversion mechanism in the expanding universe and assuming three neutrino families with identical mass, a neutrino mass of \"\" eV/c2 has been found as well as a natural explanation for the difference in Hubble constant \"\" as measured by WMAP/Planck and obtained from LSS data. The value for the effective number of neutrinos \"\" at the time of decoupling is compatible with the Planck result. The age of the universe is slightly younger at \"\" Gyr. At late times, the closure parameter for the neutrino radiation \"\" drastically increases but still remains well below that of the baryons \"\" , among other energy contributions.
Plasma folate levels are associated with the lipoprotein profile: a retrospective database analysis
Alexander Semmler, Susanna Moskau, Andreas Grigull, Susan Farmand, Thomas Klockgether, Yvo Smulders, Henk Blom, Bernd Zur, Birgit Stoffel-Wagner, Michael Linnebank
Nutrition Journal , 2010, DOI: 10.1186/1475-2891-9-31
Abstract: In a retrospective single center approach, we analyzed the laboratory database (2003-2006) of the University Hospital Bonn, Germany, including 1743 individuals, in whom vitamin B12, folate and at least one lipoprotein parameter had been determined by linear multilogistic regression.Higher folate serum levels were associated with lower serum levels of low density lipoprotein cholesterol (LDL-C; Beta = -0.164; p < 0.001), higher levels of high density lipoprotein cholesterol (HDL-C; Beta = 0.094; p = 0.021 for trend) and a lower LDL-C-C/HDL-C-ratio (Beta = -0.210; p < 0.001). Using ANOVA, we additionally compared the individuals of the highest with those of the lowest quartile of folate. Individuals of the highest folate quartile had higher levels of HDL-C (1.42 ± 0.44 mmol/l vs. 1.26 ± 0.47 mmol/l; p = 0.005), lower levels of LDL-C (3.21 ± 1.04 mmol/l vs. 3.67 ± 1.10 mmol/l; p = 0.001) and a lower LDL-C/HDL-C- ratio (2.47 ± 1.18 vs. 3.77 ± 5.29; p = 0.002). Vitamin B12 was not associated with the lipoprotein profile.In our study sample, high folate levels were associated with a favorable lipoprotein profile. A reconfirmation of these results in a different study population with a well defined status of health, diet and medication is warranted.Increased homocysteine (Hcys) levels and altered plasma lipid levels are generally considered to be independent risk factors for the development of cardiovascular disease (CVD). However, lifestyle and nutrition may cause a coincidence of the homocysteine and lipoprotein status. Although of potential clinical and scientific relevance such a relationship is not generally acknowledged.Recent studies have already described an inverse relationship between folate and high-density lipoprotein cholesterol (HDL-C) levels and low folate levels have therefore been suggested to be a cardiovascular risk factor and that the subjects with lower folate levels should be recommended for dietary folic acid supplementation to HDL-C levels [1,2].Sev
The Effect of Nitrogen and Phosphorus Ratios and Electrical Conductivity on Plant Growth  [PDF]
Laura Wiser, Theo J. Blom
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.712150
Abstract: Environmental concerns surround the use of plant growth retardants (PGRs) for plant height control, and non-chemical alternatives to PGRs can be labor intensive and expensive. Macronutrient modification is a little-studied, yet potentially effective method of controlling plant height. A number of studies have suggested that phosphorus (P) limitation may restrict plant height. Anecdotal evidence also suggests that using nitrate (NO3-), rather than ammonium (NH4+), as the principal nitrogen (N) source may help control plant height. The primary objective of this study was to evaluate different ratios of NO3-/ NH4+, NO3-/P and NH4+/P as well as electrical conductivity (EC) on plant height and growth. This was tested in a hydroponic system using marigolds, sunflowers and tomatoes. Initially, different ratios were tested at an EC of 1.2 dS·m-1, followed by using the same ratios at four ECs (0.6, 1.2, 2.2 and 4.0 dS·m-1) as a second objective. Although ratios did, at times, limit plant height, responses were season and species dependent, suggesting that modifications in plant nutrition, at the ratios used in this study, may not effectively control plant height in hydroponic systems. More consistent, yet species specific, height control was achieved by increasing EC level.
"How to have healthy children": Responses to the falling birth rate in Norway, c. 1900-1940
Dynamis , 2008, DOI: 10.4321/S0211-95362008000100007
Abstract: this paper focuses on initiatives to improve infant health, as they developed in norway especially during the interwar period. falling birth rates were felt as a menace to the survival of the nation and specific initiatives were taken to oppose it. but crises engendered by the reduction in fertility strengthened opportunities for introducing policies to help the fewer children born survive and grow up to become healthy citizens. legislation supporting mothers started in 1892 increased in the interwar years including economic features. healthy mother and baby stations and hygienic clinics, aimed at controlling births were developed by voluntary organisations inspired from france and england respectively. a sterilization law (1934) paralleled some german policies.
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