Specific questions in wildlife research and surveillance require safe and efficient capture, handling and anaesthesia protocols to enable sampling and transmitter placement in free-ranging individuals. For wild felids, various protocols are available, but detailed reports for European wildcats ( Felis silvestris ) are scarce. In particular, tools for anaesthesia monitoring under field conditions and reference values for heart rate, respiratory rate, oxygen saturation and body temperature are missing. In the present study, European wildcats were caught in box traps before being released into catch bags for manual restraint. Inside the bags, ketamine-xylazine anaesthesia was applied via intramuscular injection, adjusted to the animal’s body weight. During anaesthesia, samples were taken, and vital variables were monitored continuously. Haematology and blood chemistry parameters were obtained, along with serological markers for antibodies against feline immunodeficiency virus (FIV), feline coronavirus and antigens of feline leukaemia virus (FeLV). In total, 29 wildcats were captured, of which 21 were examined and marked with passive integrated transponders. Twelve wildcats were collared with GPS transmitters. Handling time under anaesthesia averaged 30 min (range 26–35 min). Heart rate ranged between 76 and 170 beats/min and respiratory rate between 20 and 52 breaths/min. Relative arterial oxygen saturation stayed mainly between 93 and 99%, and rectal temperature ranged between 36.2 and 40.2 °C. Further, FeLV antibodies were detected in 2/21 samples. The applied protocol facilitated safe and sufficient examination, sampling and transmitter placement, as well as the establishment of haematological and blood chemical values in free-ranging European wildcats for the first time.

Humans have transformed most landscapes across the globe, forcing other species to adapt in order to persist in increasingly anthropogenic landscapes. Wide-ranging solitary species, such as wild felids, struggle particularly in such landscapes. Conservation planning and management for their long-term persistence critically depends on understanding what determine survival and what are the main mortality risks. We carried out the first study on annual survival and cause-specific mortality of the European wildcat with a large and unique dataset of 211 tracked individuals from 22 study areas across Europe. Furthermore, we tested the effect of environmental and human disturbance variables on the survival probability. Our results show that mortalities were mainly human-caused, with roadkill and poaching representing 57% and 22% of the total annual mortality, respectively. The annual survival probability of wildcat was 0.92 (95% CI = 0.87-0.98) for females and 0.84 (95% CI = 0.75-0.94) for males. Road density strongly impacted wildcat annual survival, whereby an increase in the mad density of motorways and primary roads by 1 km/km(2) in wildcat home-ranges increased mortality risk ninefold. Low-traffic roads, such as secondary and tertiary roads, did not significantly affect wildcat's annual survival. Our results deliver key input parameters for population viability analyses, provide planning-relevant information to maintain subcritical road densities in key wildcat habitats, and identify conditions under which wildcat-proof fences and wildlife crossing structures should be installed to decrease wildcat mortality.

Background and purposeProton radiotherapy offers the potential to reduce normal tissue toxicity. However, clinical safety margins, range uncertainties, and varying relative biological effectiveness (RBE) may result in a critical dose in tumor-surrounding normal tissue. To assess potential adverse effects in preclinical studies, image-guided proton mouse brain irradiation and analysis of DNA damage repair was established.Material and methodsWe designed and characterized a setup to shape proton beams with 7 mm range in water and 3 mm in diameter and commissioned a Monte Carlo model for in vivo dose simulation. Cone-beam computed tomography and orthogonal X-ray imaging were used to delineate the right hippocampus and position the mice. The brains of three C3H/HeNRj mice were irradiated with 8 Gy and excised 30 min later. Initial DNA double-strand breaks were visualized by staining brain sections for cell nuclei and γH2AX. Imaged sections were analyzed with an automated and validated processing pipeline to provide a quantitative, spatially resolved radiation damage indicator.ResultsThe analyzed DNA damage pattern clearly visualized the radiation effect in the mouse brains and could be mapped to the simulated dose distribution. The proton beam passed the right hippocampus and stopped in the central brain region for all evaluated mice.ConclusionWe established image-guided proton irradiation of mouse brains. The clinically oriented workflow facilitates (back-) translational studies. Geometric accuracy, detailed Monte Carlo dose simulations, and cell-based assessment enable a biologically and spatially resolved analysis of radiation response and RBE.

PurposeTo determine the volume recombination at high dose‐per‐pulse in liquid ionization chambers (LIC) and to ascertain whether existing calculation methods verified in air‐filled chambers may be used to calculate a correction factor.MethodsTwo LICs, one filled with 2,2,4‐trimethylpentane (isooctane) the other with tetramethylsilane (TMS), were irradiated in a pulsed, 20 MeV electron beam. Via reference measurements with a Faraday cup, the saturation correction for volume recombination was determined for dose‐per‐pulse values ranging from about 5 mGy to 1 Gy for both chambers at a pulse duration of 693 ns. In addition, the isooctane chamber was irradiated with pulses of varying duration, ranging from 5 ps to 10 ms, at a dose‐per‐pulse of about 76.5 mGy. The dose‐per‐pulse‐dependent measurements were compared to calculations based on Boag's models (with and without a free electron fraction), the two‐dose‐rate method, and a numerical calculation. The pulse duration dependent measurements were compared only to a numerical calculation that iteratively calculates the charge transport and loss in a 1D model of an ionization chamber.ResultsIn TMS only Boag's model with a free electron fraction and the numerical calculation are in good agreement with the experimental data. However, in isooctane, good agreement is observed between the experimental data, the numerical calculation as well as the two‐dose‐rate method, and Boag's model including a free electron fraction. Only Boag's model without a free electron fraction shows a good agreement with lesser extend. Furthermore, the pulse duration‐dependent data for isooctane are well described by the numerical model.ConclusionWith isooctane as an active medium, a LIC could be directly used in a field with high dose‐per‐pulse utilizing the well‐established two‐dose‐rate method to correct the volume recombination. In addition, pulsed fields with variable pulse duration are easily modeled for this medium using a numerical calculation. Other media, as exemplified by the TMS‐filled chamber, might require additional considerations, such as including a fraction of free electrons in the consideration of volume recombination.

In order to describe the volume recombination in a pulsed radiation field of high dose-per-pulse this study presents a numerical solution of a 1D transport model of the liberated charges in a plane-parallel ionization chamber. In addition, measurements were performed on an Advanced Markus ionization chamber in a pulsed electron beam to obtain suitable data to test the calculation. The experiment used radiation pulses of 4 μs duration and variable dose-per-pulse values up to about 1 Gy, as well as pulses of variable duration up to 308 [Formula: see text] at constant dose-per-pulse values between 85 mGy and 400 mGy. Those experimental data were compared to the developed numerical model and existing descriptions of volume recombination. At low collection voltages the observed dose-per-pulse dependence of volume recombination can be approximated by the existing theory using effective parameters. However, at high collection voltages large discrepancies are observed. The developed numerical model shows much better agreement with the observations and is able to replicate the observed behavior over the entire range of dose-per-pulse values and collection voltages. Using the developed numerical model, the differences between observation and existing theory are shown to be the result of a large fraction of the charge being collected as free electrons and the resultant distortion of the electric field inside the chamber. Furthermore, the numerical solution is able to calculate recombination losses for arbitrary pulse durations in good agreement with the experimental data, an aspect not covered by current theory. Overall, the presented numerical solution of the charge transport model should provide a more flexible tool to describe volume recombination for high dose-per-pulse values as well as for arbitrary pulse durations and repetition rates.

Only few ten radiotherapy facilities worldwide provide ion beams, in spite of their physical advantage of better achievable tumor conformity of the dose compared to conventional photon beams. Since, mainly the large size and high costs hinder their wider spread, great efforts are ongoing to develop more compact ion therapy facilities. One promising approach for smaller facilities is the acceleration of ions on micrometre scale by high intensity lasers. Laser accelerators deliver pulsed beams with a low pulse repetition rate, but a high number of ions per pulse, broad energy spectra and high divergences. A clinical use of a laser based ion beam facility requires not only a laser accelerator providing beams of therapeutic quality, but also new approaches for beam transport, dosimetric control and tumor conformal dose delivery procedure together with the knowledge of the radiobiological effectiveness of laser-driven beams. Over the last decade research was mainly focused on protons and progress was achieved in all important challenges. Although currently the maximum proton energy is not yet high enough for patient irradiation, suggestions and solutions have been reported for compact beam transport and dose delivery procedures, respectively, as well as for precise dosimetric control. Radiobiological in vitro and in vivo studies show no indications of an altered biological effectiveness of laser-driven beams. Laser based facilities will hardly improve the availability of ion beams for patient treatment in the next decade. Nevertheless, there are possibilities for a need of laser based therapy facilities in future.

Radiation therapy is an important modality in cancer treatment. Compact electron linear accelerators are widely used to provide electron and photon beams with a maximum energy of about 20 MeV for tumor irradiation. Heavy charged particles (protons and heavier ions) due to their superior dose profile over photons and electrons, provide higher tumor dose conformity and healthy tissue sparing. But due to high costs and huge size of existing facilities, ion therapy is limited to few, large centers only.

The European wildcat (Felis silvestris silvestris) is a threatened and elusive species that was previously considered to be forest-bound in central Europe. For the first time, we caught and radio-collared wildcats outside heavily forested habitats to investigate their habitat utilization pattern. We used a generalized linear modelling framework to test our hypotheses that sex and season influence habitat selection in addition to habitat variables. Our results reveal a gender difference in habitat selection: Females were more restricted to areal shelter habitats and avoided the areas near roads more than did males. Males used more linear shelter habitats such as watercourses or hedges and avoided the proximity to settlements more than did females. The probability of wildcat occurrence far from shelter habitats was higher in summer than in winter, probably due to high coverage and shelter provided by crops. The same pattern applied to the proximity to roads. We concluded that shelter habitats are one of the key factors for the occurrence of wildcats in agriculturally dominated landscapes. We recommend a management strategy that enhances structural heterogeneity in the agricultural landscape by conserving small-scale structures such as copses, hedges and wide field margins. Other species, such as the gray-partridge (Perdix perdix) and the common quail (Coturnix corturnix), can also benefit from these habitat recommendations. Additionally, this management strategy simultaneously creates habitat connectivity.

The European wildcat, Felis silvestris silvestris, serves as a prominent target species for the reconnection of central European forest habitats. Monitoring of this species, however, appears difficult due to its elusive behaviour and the ease of confusion with domestic cats. Recently, evidence for multiple wildcat occurrences outside its known distribution has accumulated in several areas across Central Europe, questioning the validity of available distribution data for this species. Our aim was to assess the fine-scale distribution and genetic status of the wildcat in its central European distribution range. We compiled and analysed genetic samples from roadkills and hundreds of recent hair-trapping surveys and applied phylogenetic and genetic clustering methods to discriminate wild and domestic cats and identify population subdivision. 2220 individuals were confirmed as either wildcat (n = 1792) or domestic cat (n = 342), and the remaining 86 (3.9 %) were identified as hybrids between the two. Remarkably, genetic distinction of domestic cats, wildcats and their hybrids was only possible when taking into account the presence of two highly distinct genetic lineages of wildcats, with a suture zone in central Germany. 44 % of the individual wildcats where sampled outside the previously published distribution. Our analyses confirm a relatively continuous spatial presence of wildcats across large parts of the study area in contrast to previous analyses indicating a highly fragmented distribution. Our results suggest that wildcat conservation and management should take advantage of the higher than previously assumed dispersal potential of wildcats, which may use wildlife corridors very efficiently.

In current clinical radiotherapy electron, photon and ion beams are delivered (quasi-) continuously with typical dose-rates of a few Gy/min. Recent developments in dose delivery like IMRT and respiratory-gated treatment as well as accelerator techniques like flattening filter free Linacs and laser-based particle accelerators are driven towards intermittent irradiation with higher dose rates. Compared to continuous dose delivery these new techniques differ not only in dose rate, but also in the temporal sequence of pulse delivery, i.e. pulse lengths and pulse intervals. Previous studies on the influence of high dose rates were focussed on single pulse electron exposure and vary in energy, pulse duration and cell line; the impact of intermittent irradiation was rarely investigated. In the present work, the influence of dose rates of up to 1012 Gy/min and of intermittent irradiation with pulse lengths and pulse intervals in the range of seconds were studied. The radiation source ELBE (Electron Linac for beams with high Brilliance and low Emittance) was used to mimic intermittent irradiation with asymmetric split-doses, separated by pulse intervals in the range of 10 ms to 90 s, and the quasi-continuous electron beam of a clinical LINAC. Using the HNSCC line SQ20B the impact of pulse structure was analyzed by clonogenic survival assay. Moreover, the LINAC-like electron beam and electron pulses with pulse dose rates of up to 1012 Gy/min were used to measure the kinetics of g-H2AX/53BP1 foci disappearance up to 24 h after treatment as a surrogate marker for DNA double-strand break complexity in the normal human breast epithelial cell line 184A1. In general, the radiation response was found to be independent from electron pulse structure for the two endpoints under investigation. These results reveal that ultra-high pulse dose rates of 1012 Gy/min and pulse intervals of 10 ms to 90 s between two pulses have no significant influence on the radiobiological effectiveness of megavoltage electrons.

Aim: Proton beams by their advantageous dose profile over conventional photon and electron beams may provide higher dose conformity and better healthy tissue sparing. But due to high costs and huge size of existing facilities, proton therapy is limited to few centers. A novel proton acceleration, on µm scale by ultra-intense lasers, promises compact accelerators and beam delivery systems. Unlike conventional proton beams, laser-accelerated proton (LAP) beam is characterized by short ultra-intense pulses with peak dose rates exceeding conventional values by ∼9 orders of magnitude but low repetition rate, broad energy spread and large divergence. They require completely new techniques of beam transport, dose delivery and quality assurance along with radiobiological characterization.

Pulsed radiation fields, characterized by microsecond pulse duration and correspondingly high pulse dose rates, are increasingly used in therapeutic, diagnostic and research applications. Yet, dose rate meters which are used to monitor radiation protection areas or to inspect radiation shielding are mostly designed, characterized and tested for continuous fields and show severe deficiencies in highly pulsed fields. Despite general awareness of the problem, knowledge of the specific limitations of individual instruments is very limited, complicating reliable measurements. We present here the results of testing three commercial dose rate meters, the RamION ionization chamber, the LB 1236-H proportional counter and the 6150AD-b scintillation counter, for their response in pulsed radiation fields of varied pulse dose and duration. Of these three the RamION proved reliable, operating in a pulsed radiation field within its specifications, while the other two instruments were only able to measure very limited pulse doses and pulse dose rates reliably.

Detailed information on resting site requirements of the endangered European wildcat (Felis silvestris silvestris, Schreber, 1777) is so far not well documented. Previous investigations on the ecology of wildcats listed only the used requisites for day time resting itself but did not analyse the direct surroundings of a requisite or the demands imposed by wildcats on their resting site, even though adequate resting sites are an important issue in wildlife conservation. In 2005, between late April and end of October, we conducted an investigation on the diurnal resting sites of three male radio-tracked wildcats followed by environmental mapping in the lower Harz Mountains (Saxony-Anhalt, Germany). The analysis of resting sites was carried out on three spatial scales: the requisite (specific object that was used for resting e.g. root plate, hunting hide) in the center; the microhabitat (quality of the surrounding of the requisite in 2m radius); and the resting site (quality of the surrounding of the requisite in 25m radius). Resting requisites were mostly situated on ground level and deadwood structures were often used. Microhabitats were dominated by a herb layer >50cm in height. A generalised linear model (GLM) showed that the observed wildcats preferred resting sites in shelter structures near forest edges. The selection of resting sites was not strongly affected by man-made structures like roads or villages. Our results emphasise the importance of shelter structures, in particular deadwood structures for wildcat conservation. Therefore, we recommend a forest management strategy which enhances structural heterogeneity by (natural) gap dynamic and with a high amount of deadwood, such as crowns or brushwood.