29 research outputs found
Typical dynamics of plane rational maps with equal degrees
Let be a rational map with
algebraic and topological degrees both equal to . Little is known in
general about the ergodic properties of such maps. We show here, however, that
for an open set of automorphisms , the
perturbed map admits exactly two ergodic measures of maximal entropy
, one of saddle and one of repelling type. Neither measure is supported
in an algebraic curve, and is `fully two dimensional' in the sense
that it does not preserve any singular holomorphic foliation. Absence of an
invariant foliation extends to all outside a countable union of algebraic
subsets. Finally, we illustrate all of our results in a more concrete
particular instance connected with a two dimensional version of the well-known
quadratic Chebyshev map.Comment: Many small changes in accord with referee comments and suggestion
High frequency of chlamydial co-infections in clinically healthy sheep flocks
<p>Abstract</p> <p>Background</p> <p>The epidemiological situation of ovine chlamydial infections in continental Europe, especially Germany is poorly characterised. Using the German state of Thuringia as a model example, the chlamydial sero- and antigen prevalence was estimated in thirty-two randomly selected sheep flocks with an average abortion rate lower than 1%. Seven vaccinated flocks were reviewed separately.</p> <p>Results</p> <p>A wide range of samples from 32 flocks were examined. Assumption of a seroprevalence of 10% (CI 95%) at flock level, revealed that 94% of the tested flocks were serologically positive with ongoing infection (i.e. animals with seroconversion) in nearly half (47%) of the flocks. On the basis of an estimated 25% antigen prevalence (CI 95%), PCR and DNA microarray testing, together with sequencing revealed the presence of chlamydiae in 78% of the flocks. The species most frequently found was <it>Chlamydophila (C</it>.) <it>abortus </it>(50%) followed by <it>C. pecorum </it>(47%) and <it>C. psittaci </it>genotype A (25%). Mixed infections occurred in 25% of the tested flocks. Samples obtained from the vaccinated flocks revealed the presence of <it>C. abortus </it>field samples in 4/7 flocks. <it>C. pecorum </it>was isolated from 2/7 flocks and the presence of seroconversion was determined in 3/7 flocks.</p> <p>Conclusions</p> <p>The results imply that chlamydial infections occur frequently in German sheep flocks, even in the absence of elevated abortion rates. The fact that <it>C. pecorum </it>and the potentially zoonotic <it>C. psittaci </it>were found alongside the classical abortifacient agent <it>C. abortus</it>, raise questions about the significance of this reservoir for animal and human health and underline the necessity for regular monitoring. Further studies are needed to identify the possible role of <it>C. psittaci </it>infections in sheep.</p
Phytosaurs
p. 57-96, [9] p. of plates (1 folded) : ill. ; 27 cm.Includes bibliographical references (p. 95-96)
Prevalence of Coxiella burnetii in clinically healthy German sheep flocks
<p>Abstract</p> <p>Background</p> <p>Current epidemiological data on the situation of <it>Coxiella (C.) burnetii </it>infections in sheep are missing, making risk assessment and the implementation of counteractive measures difficult. Using the German state of Thuringia as a model example, the estimated sero-, and antigen prevalence of <it>C. burnetii </it>(10% and 25%, respectively) was assessed at flock level in 39/252 randomly selected clinically healthy sheep flocks with more than 100 ewes and unknown abortion rate.</p> <p>Results</p> <p>The CHECKITâą Q-fever Test Kit identified 11 (28%) antibody positive herds, whereas real-time PCR revealed the presence of <it>C. burnetii </it>DNA in 2 (5%) of the flocks. Multiple-locus variable number of tandem repeats analysis of 9 isolates obtained from one flock revealed identical profiles. All isolates contained the plasmid QpH1.</p> <p>Conclusions</p> <p>The results demonstrate that <it>C. burnetii </it>is present in clinically inconspicuous sheep flocks and sporadic flare-ups do occur as the notifications to the German animal disease reporting system show. Although <it>C. burnetii </it>infections are not a primary veterinary concern due to the lack of significant clinical impact on animal health (with the exception of goats), the eminent zoonotic risk for humans should not be underestimated. Therefore, strategies combining the interests of public and veterinary public health should include monitoring of flocks, the identification and culling of shedders as well as the administration of protective vaccines.</p
Typical dynamics of plane rational maps with equal degrees
Let f:CP2âąCP2 be a rational map with algebraic and topological degrees both equal to dâ„2. Little is known in general about the ergodic properties of such maps. We show here, however, that for an open set of automorphisms T:CP2âCP2, the perturbed map Tâf admits exactly two ergodic measures of maximal entropy logd, one of saddle type and one of repelling type. Neither measure is supported in an algebraic curve, and fT is 'fully two dimensional' in the sense that it does not preserve any singular holomorphic foliation of CP2. In fact, absence of an invariant foliation extends to all T outside a countable union of algebraic subsets of Aut(P2). Finally, we illustrate all of our results in a more concrete particular instance connected with a two dimensional version of the well-known quadratic Chebyshev map
Is having a job a protective factor? Employment status and state of medical care as subjectively perceived by adults with CHD in Germany
Background: Most patients born with CHD nowadays reach adulthood, and thus quality of life, life situation, and state of medical care aspects are gaining importance in the current era. The present study aimed to investigate whether patients' assessment depends on their means of occupation. The findings are expected to be helpful in optimising care and for developing individual treatment plans. Methods: The present study was based on an online survey conducted in cooperation with patient organisations. Participants were recruited from the database of the German National Register for Congenital Heart Defects. In total, 1828 individuals (777 males, 1051 females) took part. Participants were asked to rate aspects such their state of health on a six-tier scale (1=worst specification). Response behaviour was measured against the background of occupational details. Results: Training for or pursuing a profession was found to be significantly associated with participants' rating of five of the six examined aspects (p<0.05). Sex seemed to play an important part in four of the six aspects. Conclusions: An optimal treatment plan for adults with CHD should always consider aspects such as sex and employment status. To work out such an optimal and individual treatment plan for each adult CHD patient, an objective tool to measure patients' actual CHD-specific knowledge precluding socially accepted response bias would be very useful