168 research outputs found
Transport in quasi one-dimensional spin-1/2 systems
No full textWe present numerical results for the spin and thermal conductivity of
one-dimensional (1D) quantum spin systems. We contrast the properties of
integrable models such as the spin-1/2 XXZ chain against nonintegrable ones such as
frustrated and dimerized chains. The thermal conductivity of the XXZ chain
is ballistic at finite temperatures, while in the nonintegrable models, this quantity is argued
to vanish. For the case of frustrated and dimerized chains, we discuss
the
frequency dependence of the transport coefficients. Finally, we give an overview over related theoretical
work on intrinsic and extrinsic scattering mechanisms of quasi-1D spin systems
Origin, distribution and relevance of the CVM defect within the Holstein-Friesian population
No full textComplex Vertebral Malformations (CVM) was first reported in Denmark. After independent studies in The Netherlands proved that CVM is an autosomal recessive inherited disorder, it was officially decided to screen the Holstein population. In the meantime a direct DNA-based test has been developed and is used world-wide. Especially progeny of Ivanhoe Star and Bell in the Dutch and Danish populations are affected. To evaluate the frequency of CVM in the population, we have determined the number of CVM carriers in German sires. The analysis of a total of 957 sires showed that the frequency of CVM affected animals was 13.2%. The number was dependent on the date of birth and the usage of bull fathers. Depending on the calculated CVM frequency the possibility of a CVM-homozygote calf is between 0.3 to 0.45%. Although the distribution and frequency of CVM carriers is rather high, there have been no reports of CVM cases in the German Holstein population. Nevertheless the severity of the CVM defect should not be underestimated. However, since the defect gene seems to be linked to favourable performance genes its radical elimination may lead to their losses as well
Origin, distribution and relevance of the CVM defect within the Holstein-Friesian population
No full textComplex Vertebral Malformations (CVM) was first reported in Denmark. After independent studies in The Netherlands proved that CVM is an autosomal recessive inherited disorder, it was officially decided to screen the Holstein population. In the meantime a direct DNA-based test has been developed and is used world-wide. Especially progeny of Ivanhoe Star and Bell in the Dutch and Danish populations are affected. To evaluate the frequency of CVM in the population, we have determined the number of CVM carriers in German sires. The analysis of a total of 957 sires showed that the frequency of CVM affected animals was 13.2%. The number was dependent on the date of birth and the usage of bull fathers. Depending on the calculated CVM frequency the possibility of a CVM-homozygote calf is between 0.3 to 0.45%. Although the distribution and frequency of CVM carriers is rather high, there have been no reports of CVM cases in the German Holstein population. Nevertheless the severity of the CVM defect should not be underestimated. However, since the defect gene seems to be linked to favourable performance genes its radical elimination may lead to their losses as well
Comment on “Anomalous Thermal Conductivity of Frustrated Heisenberg Spin Chains and Ladders
No full textA Comment on the Letter by J.V. Alvarez and Claudius Gros, Phys. Rev. Lett. 89, 156603 (2002). The authors of the Letter offer a Reply. © 2004 The American Physical Society.Fil: Heidrich-Meisner, F.. Institut für Theoretische Physik; AlemaniaFil: Honecker, A.. Institut für Theoretische Physik; AlemaniaFil: Cabra, Daniel Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Centre National de la Recherche Scientifique. Laboratoire de Physique Et Chimie de I´environnement Et de I´espace; FranciaFil: Brenig, W.. Institut für Theoretische Physik; Alemani
Detection of classical and atypical/Nor98 scrapie by the paraffin-embedded tissue blot method
No full textThe paraffin-embedded tissue (PET) blot method was used to investigate sections of the central nervous system and lymphatic tissues from 24 cases of classical scrapie and 25 cases of atypical/Nor98 scrapie in sheep and four healthy control sheep. The PET blot detected deposits of PrP(Sc) in the brain tissue of all 49 sheep with scrapie but no PrP(Sc) labelling could be detected in the control sheep. By contrast, not all the atypical/Nor98 scrapie cases were detectable by immunohistochemistry. The high sensitivity of the PET blot method made it possible to observe that in some atypical/Nor98 cases, deposits of PrP(Sc) may be restricted to supratentorial brain structures and that the diagnosis may be missed when only testing the obex area, where deposits are common in classical scrapie, and the cerebellar structures, where deposits are considered to be common in atypical/Nor98 cases
Characterization and linkage mapping of 15 porcine STS markers to fine‐map chromosomal regions associated with hernia inguinalis/scrotalis
No full textTransport in dimerized and frustrated spin systems
No full textWe analyze the Drude weight for both spin and thermal transport of one-dimensional spin-12 systems by means of exact diagonalization at finite temperatures. While the Drude weights are non-zero for finite systems, we find indications of a vanishing of the Drude weights in the thermodynamic limit for non-integrable models implying normal transport behavior.Fil: Heidrich Meisner, F.. Technische Universitat Carolo Wilhelmina Zu Braunschweig.; AlemaniaFil: Honecker, A.. Technische Universitat Carolo Wilhelmina Zu Braunschweig.; AlemaniaFil: Cabra, Daniel Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Ecole Normale Supérieure de Lyon; FranciaFil: Brenig, W.. Technische Universitat Carolo Wilhelmina Zu Braunschweig.; Alemani
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