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R Joosten

Publications and source records attributed to R Joosten.

At least 19 recordsLinked to original sources
PubMed2006

Genetic diversity analysis using lowly polymorphic dominant markers: the example of AFLP in pigs.

DNA markers are commonly used for large-scale evaluation of genetic diversity in farm animals, as a component of the management of animal genetic resources. AFLP markers are useful for such studies as they can be generated relatively simply; however, challenges in analysis arise from their dominant scoring and the low level of polymorphism of some markers. This paper describes the results obtained with a set of AFLP markers in a study of 59 pig breeds. AFLP fingerprints were generated using four primer combinations (PC), yielding a total of 148 marker loci, and average harmonic mean of breed sample size was 37.3. The average proportion of monomorphic populations was 63% (range across loci: 3%-98%). The moment-based method of Hill and Weir (2004, Mol Ecol 13:895-908) was applied to estimate gene frequencies, gene diversity (F(ST)), and Reynolds genetic distances. A highly significant average F(ST) of 0.11 was estimated, together with highly significant PC effects on gene diversity. The variance of F(ST) across loci also significantly exceeded the variance expected under the hypothesis of AFLP neutrality, strongly suggesting the sensitivity of AFLP to selection or other forces. Moment estimates were compared to estimates derived from the square root estimation of gene frequency, as currently applied for dominant markers, and the biases incurred in the latter method were evaluated. The paper discusses the hypotheses underlying the moment estimations and various issues relating to the biallelic, dominant, and lowly polymorphic nature of this set of AFLP markers and to their use as compared to microsatellites for measuring genetic diversity.

Animals↗
PubMed2006

Genetic diversity within and between European pig breeds using microsatellite markers.

An important prerequisite for a conservation programme is a comprehensive description of genetic diversity. The aim of this study was to use anonymous genetic markers to assess the between- and the within-population components of genetic diversity for European pig breeds at the scale of the whole continent using microsatellites. Fifty-eight European pig breeds and lines were analysed including local breeds, national varieties of international breeds and commercial lines. A sample of the Chinese Meishan breed was also included. Eleven additional breeds from a previous project were added for some analyses. Approximately 50 individuals per breed were genotyped for a maximum of 50 microsatellite loci. Substantial within-breed variability was observed, with the average expected heterozygosity and observed number of alleles per locus being 0.56 [range 0.43-0.68] and 4.5 respectively. Genotypic frequencies departed from Hardy-Weinberg expectations (P < 0.01) in 15 European populations, with an excess of homozygotes in 12 of them. The European breeds were on average genetically very distinct, with a Wright F(ST) index value of 0.21. The Neighbour-Joining tree drawn from the Reynolds distances among the breeds showed that the national varieties of major breeds and the commercial lines were mostly clustered around their breeds of reference (Duroc, Hampshire, Landrace, Large White and Piétrain). In contrast, local breeds, with the exception of the Iberian breeds, exhibited a star-like topology. The results are discussed in the light of various forces, which may have driven the recent evolution of European pig breeds. This study has consequences for the interpretation of biodiversity results and will be of importance for future conservation programmes.

Alleles↗
PubMed2006

Genetic diversity in European pigs utilizing amplified fragment length polymorphism markers.

The use of DNA markers to evaluate genetic diversity is an important component of the management of animal genetic resources. The Food and Agriculture Organisation of the United Nations (FAO) has published a list of recommended microsatellite markers for such studies; however, other markers are potential alternatives. This paper describes results obtained with a set of amplified fragment length polymorphism (AFLP) markers as part of a genetic diversity study of European pig breeds that also utilized microsatellite markers. Data from 148 AFLP markers genotyped across samples from 58 European and one Chinese breed were analysed. The results were compared with previous analyses of data from 50 microsatellite markers genotyped on the same animals. The AFLP markers had an average within-breed heterozygosity of 0.124 but there was wide variation, with individual markers being monomorphic in 3-98% of the populations. The biallelic and dominant nature of AFLP markers creates a challenge for their use in genetic diversity studies as each individual marker contains limited information and AFLPs only provide indirect estimates of the allelic frequencies that are needed to estimate genetic distances. Nonetheless, AFLP marker-based characterization of genetic distances was consistent with expectations based on breed and regional distributions and produced a similar pattern to that obtained with microsatellites. Thus, data from AFLP markers can be combined with microsatellite data for measuring genetic diversity.

Alleles↗
PubMed2005

First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering.

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

Journal Article↗
PubMed2005

Neutral-pion photoproduction off protons in the energy range 0.3 GeV<E(gamma)<3 GeV.

Single pi(0) photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of approximately 98% of 4pi. Differential cross sections dsigma/dOmega have been measured. Complicated structures in the angular distributions indicate a variety of different resonances being produced in the s channel intermediate state gammap-->N(*)(Delta(*))-->ppi(0). A combined analysis including the data presented in this letter along with other data sets reveals contributions from known resonances and evidence for a new resonance N(2070)D15.

Journal Article↗
PubMed2005

Photoproduction of eta mesons off protons for 0.75 GeV<E(gamma)<3 GeV.

Total and differential cross sections for the reaction p(gamma,eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S11 wave which has two poles in the energy region below 2 GeV. Eleven nucleon resonances are observed in their decay into peta. At medium energies we find evidence for a new resonance N(2070)D15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. At gamma energies above 1.5 GeV, a strong peak in the forward direction develops, signaling the exchange of vector mesons in the t channel.

Journal Article↗
PubMed2000

Measurement of excitation functions in the reactions 197Au(11C, xn)208-xAt using a radioactive 11C beam

A light-element radioactive ion-beam capability has been developed at the LBNL 88-Inch Cyclotron. The system is based on the coupled-cyclotrons method and utilizes short-lived species, e.g., 11C, 14O, 13N produced by (p,n) and (p,alpha) reactions at the LBNL Biomedical Isotope Facility Cyclotron. In a first experiment, 197Au(11C,xn)208-xAt excitation functions have been measured for energies ranging from the Coulomb barrier up to 110 MeV using a beam of 11C with intensities up to (1-2)x10(8) ions/sec on target. The results of this experiment are compared to measurements of 197Au(12C, xn)209-xAt excitation functions.

Journal Article↗
PubMed1981

Hyperosmolar nonketotic diabetic coma.

The authors report the case of a 12-year-old boy with hyperosmolar nonketotic diabetic coma. Pathogenetic aspects and the HLA genotype are discussed. To reduce the hyperglycaemia, a continuous intravenous infusion of regular insulin at a low rate was used. The too rapidly infused sodium-bicarbonate overloaded tha body with sodium and caused intracellular sodium accumulation with edema. This could explain the disorientation after regaining consciousness. Much more important than the sodium-bicarbonate infusion is an accurate rehydration regimen.

Bicarbonates↗
PubMed1980

[Hepatitis B infection of the newborn by its symptom-free mother].

A routine screening of the serum of pregnant women for the HBs antigen in the Aachn area revealed a frequency of 1,73% symptom free carrier mothers. This proportion is three times higher as the frequency of the HBs antigen in the normal population. The risk of a vertical transmission in children born to HBs antigen positive mothers is discussed as well as extended immunological diagnosis and prophylactic use of hyperimmunglobulin.

Adult↗
PubMed1980

[Hyper-immunoglobulin-prophylaxis and follow-up in vertical hepatitis B (author's transl)].

The vertical transmission of hepatitis-B virus from chronic HBsAg carrier mothers can cause acute even fatal hepatitis-B, or a chronic HBsAg carrier state in childhood. To prevent this vertical transmission, hepatitis-B- immunoglobulin (HB Ig) is applicated. Frequency and dosis-data are still confusing. Six children were passively immunized with HB Ig according to our schedule. Their serum was controlled for HBsAg and HBsAb with the RIA-method. None of these children became HBsAg positive.

Cesarean Section↗
PubMed1980

[The vertically transmitted hepatitis B (author's transl)].

The vertically transmitted hepatitis B in infancy, is not only due to an acute hepatitis B of the mother during pregnancy. We describe 9 cases of proven vertical transmitted hepatitis B, 2 of them with fatal outcome. 5 were delivered from chronic asymptomatic HBsAg positive mothers. We wish to emphasize again the importance of HBsAg screening in pregnancy and the prophylactic use of hyperimmune gamma-globulin in children born to HBsAg positive mothers.

Child, Preschool↗
PubMed1980

[Diabetic ketoacidosis in children. Effectivity of therapy with small doses of insulin applicated intravenously versus conventional therapy (author's transl)].

Since 1972, the treatment of diabetic coma, ketoacidotic or hyperosmolar, with regular infusions of low doses of insulin, is a well-established form of therapy. Pediatricians all over the world apply this regimen regularly since 1975. In contrast to this there is the regime of intravenous or intramuscular application of high doses of insulin. To control the effectivity of these two methods, we compared two approximately identical groups of patients and analysed 17 different parameters. The patients of the low dose insulin infusion regimen needed less insulin, potassium and bicarbonate and reached earlier a bloodglucose level of 300 mg/dl. They also had a rapid and uneventful restoration of their electrolyte metabolism. Hypoglycaemia did not occur. There was no significant hypokalaemia or hypernatraemia. In contrast to this, the conventionally treated group showed much more complications. The hospital stay and the daily requirement of insulin was significantly higher. We believe that the low dose infusion regimen of insulin is a safe and easy therapeutic method. It surely is an alternative way for treating diabetic coma.

Adolescent↗