General practitioner reported incidence of Lyme carditis in the Netherlands.

BACKGROUND: Between 1994 and 2009, incidence rates of general practitioner (GP) consultations for tick bites and erythema migrans, the most common early manifestation of Lyme borreliosis, have increased substantially in the Netherlands. The current article aims to estimate and validate the incidence of GP-reported Lyme carditis in the Netherlands. METHODS: We sent a questionnaire to all GPs in the Netherlands on clinical diagnoses of Lyme borreliosis in 2009 and 2010. To validate and adjust the obtained incidence rate, medical records of cases of Lyme carditis reported by GPs in this incidence survey were reviewed and categorised according to likelihood of the diagnosis of Lyme carditis. RESULTS: Lyme carditis occurred in 0.2 % of all patients with GP-reported Lyme borreliosis. The adjusted annual incidence was six GP-reported cases of Lyme carditis per 10 million inhabitants, i.e. approximately ten cases per year in 2009 and 2010. CONCLUSIONS: We report the first incidence estimate for Lyme carditis in the Netherlands, validated by a systematic review of the medical records. Although Lyme carditis is an uncommon manifestation of Lyme borreliosis, physicians need to be aware of this diagnosis, in particular in countries where the incidence of Lyme borreliosis has increased during the past decades.

Effect of a triaxial nuclear shape on proton tunneling: the decay and structure of 145Tm.

Gamma rays deexciting states in the proton emitter 145Tm were observed using the recoil-decay tagging method. The 145Tm ground-state rotational band was found to exhibit the properties expected for an h{11/2} proton decoupled band. In addition, coincidences between protons feeding the 2{+} state in 144Er and the 2{+}-->0{+} gamma-ray transition were detected, the first measurement of this kind, leading to a more precise value for the 2{+} excitation energy of 329(1) keV. Calculations with the particle-rotor model and the core quasiparticle coupling model indicate that the properties of the pi{11/2} band and the proton-decay rates in 145Tm are consistent with the presence of triaxiality with an asymmetry parameter gamma approximately 20 degrees .

Isospin symmetry of odd-odd mirror nuclei: identification of excited states in N=Z-2 48Mn.

Excited states have been observed in the N=Z-2 odd-odd nucleus 48Mn for the first time. Through comparison with the structure of 48V, a first high-spin study of an odd-odd mirror pair has been achieved. Differences between the T=1 analogue states in this pair have been interpreted in terms of Coulomb effects, with the aid of shell-model calculations in the full pf valence space. Unlike other mirror pairs, the energy differences have been interpreted almost entirely as due to a monopole effect associated with smooth changes in radius (or deformation) as a function of angular momentum. In addition, the large energy shift between analogue negative-parity states is interpreted in terms of the electromagnetic spin-orbit interaction in nuclei.

K isomers in 254No: probing single-particle energies and pairing strengths in the heaviest nuclei.

We have identified two isomers in 254No, built on two- and four-quasiparticle excitations, with quantum numbers K pi = 8- and (14+), as well as a low-energy 2-quasiparticle Kpi = 3+ state. The occurrence of isomers establishes that K is a good quantum number and therefore that the nucleus has an axial prolate shape. The 2-quasiparticle states probe the energies of the proton levels that govern the stability of superheavy nuclei, test 2-quasiparticle energies from theory, and thereby check their predictions of magic gaps.

Structure of the odd-A, shell-stabilized nucleus 253/102No.

In-beam gamma-ray spectroscopic measurements have been made on 253/102No. A single rotational band was identified up to a probable spin of 39/2planck, which is assigned to the 7/2(+)[624] Nilsson configuration. The bandhead energy and the moment of inertia provide discriminating tests of contemporary models of the heaviest nuclei. Novel methods were required to interpret the sparse data set associated with cross sections of around 50 nb. These methods included comparisons of experimental and simulated spectra, as well as testing for evidence of a rotational band in the gammagamma matrix.

Ground state proton radioactivity from 121Pr: when was this exotic nuclear decay mode first discovered?

Ground-state proton radioactivity has been identified from 121Pr. A transition with a proton energy of E(p)=882(10) keV [Q(p)=900(10) keV] and half-life t(1/2)=10(+6)(-3) ms has been observed and is assigned to the decay of a highly prolate deformed 3/2(+) or 3/2(-) Nilsson state. The present result is found to be incompatible with a previously reported observation of ground-state proton radioactivity from 121Pr, which would have represented the discovery of this phenomenon.

Uptake of radionuclides by vegetation at a High Arctic location.

Radionuclide levels in vegetation from a High Arctic location were studied and compared to in situ soil concentrations. Levels of the anthropogenic radionuclide 137Cs and the natural radionuclides 40K, 238U, 226Ra and 232Th are discussed and transfer factor (TF) values and aggregated transfer (Tag) values are calculated for vascular plants. Levels of 137Cs in vegetation generally followed the order mosses > lichen > vascular plants. The uptake of 137Cs in vascular plants showed an inverse relationship with the uptake of 40K, with 137Cs TF and Tag values generally higher than 40K TF and Tag values. 40K activity concentrations in all vegetation showed little correlation to associated soil concentrations, while the uptake of 238U, 226Ra and 232Th by vascular and non-vascular plants was generally low.

S17(0) determined from the Coulomb breakup of 83 MeV /nucleon 8B.

A kinematically complete measurement was made of the Coulomb dissociation of 8B nuclei on a Pb target at 83 MeV/nucleon. The cross section was measured at low relative energies in order to infer the astrophysical S factor for the 7Be(p,gamma)8B reaction. A first-order perturbation theory analysis including E1, E2, and M1 transitions was employed to extract the E1 strength relevant to neutrino-producing reactions in the solar interior. By fitting the measured cross section from E(rel) = 130 to 400 keV, we find S17(0) = 17.8(+1.4)(-1.2) eV b.

Rotational bands in the proton emitter (141)Ho.

Rotational bands feeding the ground state and the isomeric state in the proton emitter (141)Ho were observed using the recoil-decay tagging method. This constitutes direct evidence that (141)Ho is deformed. A quadrupole deformation of beta(2) = 0.25(4) was deduced for the ground state from the extracted dynamic moment of inertia. Based on observed band crossings and signature splittings the 7/2(-)[523] and 1/2(+)[411] configurations were proposed for the ground state and the isomeric state, respectively. Comparison with particle-rotor calculations for beta(2) = 0.25 indicates, however, that (141)Ho may have significant hexadecapole deformation and could be triaxial in the 7/2(-)[523] ground state.

Uptake and tissue distribution of dietary and aqueous cadmium by carp (Cyprinus carpio).

The aim of this study was to assess whether contaminated prey can be a major source of Cd for fish. For this purpose, the uptake and tissue distribution of dietary and aqueous cadmium by the carp (Cyprinus carpio) was studied. The fish were exposed to either Cd-contaminated food or Cd-contaminated water for 4 weeks in laboratory experiments. When exposed to contaminated food, the fish were kept in clean water and fed contaminated chironomid larvae, equilibrated with 99 micrograms Cd. liter-1. During exposure to contaminated water (nominal 100 micrograms Cd. liter-1; actual 80 micrograms Cd. liter-1) the fish were fed uncontaminated food. The Cd accumulation in the tissues of fish fed contaminated larvae was, in decreasing order, gut > kidney > liver = gill > muscle. In the water experiment this order was gut > gill > kidney > liver > muscle. In almost all tissues the Cd uptake was similar for both routes; only the gill had accumulated more Cd from Cd-contaminated water than from Cd-contaminated food. Considering the ongoing discussion of the importance of Cd transfer from contaminated food to predators, these findings suggest that uptake of Cd from Cd-contaminated prey by fish plays an important role in contaminated waters.

Tolerance induction and life cycle changes in cadmium-exposed Chironomus riparius (Diptera) during consecutive generations.

Cultures of Chironomus riparius were exposed to cadmium during nine consecutive generations to determine whether cadmium tolerance could be induced. Selection for cadmium tolerance was assumed to influence the population dynamics of this species. Therefore, the responses and interactions of different population parameters (such as mortality, growth, and reproduction) were studied during the selection process. Exposure to cadmium during consecutive generations caused increasing effects on some life cycle parameters compared to a one-generation experiment. Tolerance to cadmium increased during exposure to 54.2 nM Cd and the tolerant population seemed to be stimulated by low cadmium concentrations (based on an acute growth experiment). Despite this tolerance development, mortality among cadmium-exposed tolerant chironomids remained high. These experiments illustrated that changes of the life cycle and tolerance can be expected as soon as single-generation NOEC values are exceeded, and in addition that "safe concentrations" based on a one-generation toxicity experiment could well underestimate the potential effects of a toxicant on midge populations.

Chronic toxicity of cadmium to Chironomus riparius (Diptera: Chironomidae) at different food levels.

The interacting effects of cadmium toxicity and food limitation on the midge, Chironomus riparius, were studied during chronic exposure in laboratory experiments. If the food was supplied ad libitum, both larval developmental time and mortality of the larvae were negatively affected by cadmium concentrations of 2.0-16.2 micrograms/L. The number of eggs deposited per female and the mean life span of the imagines were not affected by cadmium. Integration of these separate effects into a population growth rate showed a clear reduction with increasing cadmium concentrations. Food limitation of unexposed larvae at high population density reduced fitness, judged on all parameters studied and consequently reduced the population growth rate (up to 85%). The effects on larvae, which were exposed to both cadmium and food limitation, differed considerably from the response to the individual stress factors. Exposure to cadmium increased mortality among food-limited first and second instar larvae. Consequently, the amount of food available for each surviving larva increased. At the two lowest concentrations studied (2.0 and 5.6 micrograms Cd/L), these indirect positive effects of cadmium overruled the direct negative effects and caused an increase of the fitness of the food-limited exposed larvae compared to the food-limited, unexposed controls. At a concentration of 16.2 micrograms Cd/L, the negative effects of cadmium on food-limited midges balanced the positive effects of reduced food limitation. At this concentration, the population growth rate did not differ significantly from the food-limited control any more. It is concluded that the indirect positive effects of cadmium on food limitation could eliminate negative, direct effects of low cadmium concentrations on food-limited chironomid populations.

Short-term effects of metals on the filtration rate of the zebra mussel Dreissena polymorpha.

In order to study the short-term ecotoxicity of metals to the freshwater mussel Dreissena polymorpha, the effects of Cu, Zn and Cd on the filtration rate of this mussel were determined in laboratory experiments. Filtration rate was chosen as the endpoint, because it is a sensitive sublethal parameter compared to mortality and it is an important parameter given the ecological role D. polymorpha fulfills. The filtration rate was calculated from the decrease in algal concentration, fed to mussels in aquaria, containing different metal concentrations. The EC50 for Cu (41 microg litre(-1)) was lower than for Cd (388 microg litre(-1)) and Zn (1350 microg litre(-1)). The NOEC(accumulation) for the essential metal Zn was higher than for the essential metal Cu. Cadmium, a non-essential metal, was accumulated at all elevated water concentrations, so the NOEC(accumulation) was the concentration in the control water (<0.2 microg litre(-1)). All (no) effect concentrations found in this study were above the quality criteria set for metal concentrations in Dutch surface water, suggesting that the zebra mussel is sufficiently protected by these quality criteria.

Chronic ecotoxicity of copper and cadmium to the zebra mussel Dreissena polymorpha.

In order to evaluate ecological consequences of the long-term presence of metals in aquatic ecosystems, we investigated the filtration rate and survival of zebra mussels (Dreissena polymorpha) during chronic exposure to Cu and Cd. The filtration rate was measured once a week in laboratory experiments lasting 9-11 weeks. The lowest Cu concentration tested (13 micrograms/L) did not affect the filtration rate and survival of D. polymorpha, but the lowest Cd concentration (9 micrograms/L) did affect the filtration rate, but had no effect on survival. The EC50 for Cd decreased markedly from 388 micrograms/L to 27 micrograms/L when the exposure time was lengthened from 48 hours to 10 weeks. The largest decrease in EC50 for Cd was observed during the first week of exposure. In contrast, the EC50 for Cu did not decrease with increasing exposure time (chronic EC50: 43 micrograms/L). Since the chronic LC50 for Cd was 130 micrograms/L, the filtration rate appeared to be a far more sensitive endpoint for ecotoxicological laboratory experiments than mortality. D. polymorpha was capable of regulating the body concentration of the essential metal Cu at low concentrations in the water (13 micrograms/L). Cd was accumulated at every Cd concentration in the water, suggesting that Cd could not be regulated by D. polymorpha. It is concluded that the relation between short-term and long-term ecotoxicity was different for each metal and could not be predicted from the results of the short-term experiments.

Trace metals in a littoral foodweb: concentrations in organisms, sediment and water.

Cadmium, lead, zinc and copper concentrations were determined in 15 species of freshwater macro-invertebrates collected from a littoral foodweb. Indications of a biomagnification process, in which predators had a higher concentration than their prey, were only found in the case of zinc. Organisms with copper as an essential component of their haemolymph, such as Crustacaea, Gastropoda and Bivalvia, contained higher concentrations of that metal than other species. Another important factor in the determination of trace metal concentrations, apart from physiological equipment, was body weight, resulting in higher concentrations in smaller, and lower concentrations in larger, organisms. This seemed to be the case within populations of single species, as well as in different species of deposit feeders. Furthermore, feeding habit, proximity to the sediment and physico-chemical factors appeared to be determining factors for trace metal concentrations in macro-invertebrates. The results of this study are related to ecotoxicological theories which explain the causes of pollutant residues in organisms. It is concluded that various explanations for the differences in pollutant residues, e.g. trophic level, feeding habit, body weight, association with the substrate, physiological equipment and abiotic factors, are valid.

Bioturbation by cyprinid fish affecting the food availability for predatory water mites.

Field observations suggested that benthivorous fish, causing bioturbation, are able to effect the food availability for predacious water mites feeding on bottom dwelling chironomid larvae. This hypothesis was tested in the laboratory. In an undisturbed situation the predation rate exercised by the water mites on the tube dwelling chironomid Cladotanytarsus mancus was very low. However, when the sediment was disturbed, the predation rate increased substantially. The relevance of this for the field situation is discussed.