Prospective assessment of mask versus frame fixation during Gamma Knife treatment for brain metastases.

PURPOSE: The newest generation of the Leksell Gamma Knife (GK) allows frame based as well as frameless treatment. We here report outcomes of a prospective non-randomized study on mask fixation (MF) versus frame fixation (FF) for GK treatment of brain metastases. METHODS: The decision for FF or MF was made on a case-by-case basis. Factors considered were patients' preference, proximity of critical structures, V12 and treatment time. Either stereotactic radiosurgery or fractionated stereotactic radiotherapy in up to 3 fractions was performed. For MF, a PTV margin of 1 mm was added. Follow-up included quarterly MRI scans. The primary outcome was local control. Secondary endpoints were progression-free survival (PFS), overall survival (OS) and the incidence of radionecrosis. RESULTS: A total of 197 lesions (169 FF and 28 MF) were treated in 76 patients (59 FF and 17 MF). 187 lesions were treated with SRS and 10 with FSRT. Median dose was 22 Gy in both groups and median follow-up was 9.3 months. There was a higher local failure rate (HR: 3.69; 95%CI: 1.13-12.0; p = 0.03) with 11 local failures in the FF and none in the MF cohort. No differences were observed between the groups for OS (median: n.r. vs. 16.9 months; HR:1.00; 95%CI: 0.41-2.46; p = 0.999) and PFS (median: 6.9 vs. 8.4 months; HR: 0.92; 95%CI: 0.47-1.79; p = 0.800). Three cases of radionecrosis occurred with FF but none with MF (p = 0.67). CONCLUSIONS: Gamma Knife treatment with MF does not result in worse outcome or increased rates of radionecrosis in this non-randomized study.

Integrating stable isotopes, parasite, and ring-reencounter data to quantify migratory connectivity-A case study with Barn Swallows breeding in Switzerland, Germany, Sweden, and Finland.

Ecosystems around the world are connected by seasonal migration. The migrant animals themselves are influenced by migratory connectivity through effects on the individual and the population level. Measuring migratory connectivity is notoriously difficult due to the simple requirement of data conveying information about the nonbreeding distribution of many individuals from several breeding populations. Explicit integration of data derived from different methods increases the precision and the reliability of parameter estimates. We combine ring-reencounter, stable isotope, and blood parasite data of Barn Swallows Hirundo rustica in a single integrated model to estimate migratory connectivity for three large scale breeding populations across a latitudinal gradient from Central Europe to Scandinavia. To this end, we integrated a non-Markovian multistate mark-recovery model for the ring-reencounter data with normal and binomial mixture models for the stable isotope and parasite data. The integration of different data sources within a mark-recapture modeling framework enables the most precise quantification of migratory connectivity on the given broad spatial scale. The results show that northern-breeding populations and Southern Africa as well as southern-breeding populations and Western-Central Africa are more strongly connected through Barn Swallow migration than central European breeding populations with any of the African wintering areas. The nonbreeding distribution of Barn Swallows from central European breeding populations seems to be a mixture of those populations breeding further north and south, indicating a migratory divide.

Earlier breeding, lower success: does the spatial scale of climatic conditions matter in a migratory passerine bird?

Following over 20 years of research on the climatic effects on biodiversity we now have strong evidence that climate change affects phenology, fitness, and distribution ranges of different taxa, including birds. Bird phenology likely responds to changes in local weather. It is also affected by climatic year-to-year variations on larger scales. Although such scale-related effects are common in ecology, most studies analyzing the effects of climate change were accomplished using climatic information on a single spatial scale. In this study, we aimed at determining the scale-dependent sensitivity of breeding phenology and success to climate change in a migratory passerine bird, the barn swallow (Hirundo rustica). For both annual broods, we investigated effects of local weather (local scale) and the North Atlantic Oscillation (NAO, large scale) on the timing of breeding and breeding success. Consistent with previous studies in migratory birds we found that barn swallows in Eastern Germany bred progressively earlier. At the same time, they showed reduced breeding success over time in response to recent climatic changes. Responses to climatic variation were observed on both local and large climatic scales, but they differed with respect to the ecological process considered. Specifically, we found that the timing of breeding was primarily influenced by large-scale NAO variations and to a lesser extent by local weather on the breeding grounds. Conversely, climatic conditions on the local scale affected breeding success, exclusively. The observed decrease in breeding success over years is likely a consequence of scale-related mismatches between climatic conditions during different breeding phases. This provides further evidence that a species' response of earlier breeding may not be enough to cope with climate change. Our results emphasize the importance of considering the response of ecological processes along different climatic scales in order to better understand the complexity of climate change effects on biodiversity.

Tits on the move: exploring the impact of environmental change on blue tit and great tit migration distance.

1. In response to warmer spring conditions in Central Europe many migratory bird species have shifted their timing of breeding. Environmental change has also led to warmer winters, shortening the distance between the breeding grounds of migratory birds and their overwintering areas. 2. Here, we show that in response to warmer winters, blue tits (Cyanistes caeruleus), but not great tits (Parus major), breeding in Germany decreased their migration distance between 1964 and 1996. Understanding this difference provides insight into possible constraints and selection pressures involved in how species respond to environmental change. Here, we focus on their breeding ecology. 3. In a nest box population in southern Germany, both species laid their first clutch earlier with increasing spring temperature, but over the study period (1974-1999) blue tits showed a significant and stronger advancement in laying date than great tits. For both species, selection for earlier breeding did not vary with environmental change, indicating that early laying pairs did not do better than later laying pairs as spring temperature increased. 4. Blue tits in the nest box population were single-brooded and existing hypotheses state that single-brooded species likely advance their laying date to match timing of reproduction with the advancing food peak in spring. We hypothesize that this might be one reason why blue tits adjusted their migration strategy as closer proximity to the breeding grounds in winter allows better prediction of the onset of spring. Ten per cent of great tits successfully produced second broods and their first clutch laying date is a compromise between first and second clutch laying date, which might be why great tits had not advanced their laying date nor altered their migration strategy.

Serologic evidence of West Nile virus infections in wild birds captured in Germany.

To assess the risk of acquiring a West Nile virus (WNV) infection in Germany, we investigated samples from migrating and from resident birds. Because of their stay in or migration through WNV-endemic regions, these birds are at risk to become infected with WNV. Blood samples from 3,399 birds, representing 87 bird species, were collected in Germany in 2000 and in 2002-2005. Overall, 53 birds belonging to 5 species had WNV-neutralizing antibodies. Fifty-nine birds belonging to 9 species were reactive by WNV immunofluorescence assay, and 8 birds had neutralizing antibodies against Usutu virus. Because of maternal antibody transfer via egg yolk, WNV-antibody titers in white stork nestlings were generally lower than those in adults. Despite a relatively high percentage of stork nestlings with antibodies, no viral genomes were detectable by polymerase chain reaction. In Germany, the prevalence of antibodies to WNV in migrating birds wintering in Africa or southern Europe is comparatively low.