Waves of larch budmoth outbreaks in the European alps

Spatially extended population models predict complex spatiotemporal patterns, such as spiral waves and spatial chaos, as a result of the reaction-diffusion dynamics that arise from trophic interactions. However, examples of such patterns in ecological systems are scarce. We develop a quantitative technique to demonstrate the existence of waves in Central European larch budmoth (Zeiraphera diniana Gn.) outbreaks. We show that these waves travel toward the northeast-east at 210 kilometers per year. A theoretical model involving a moth-enemy interaction predicts directional waves, but only if dispersal is directionally biased or habitat productivity varies across the landscape. Our study confirms that nonlinear ecological interactions can lead to complex spatial dynamics at a regional scale.     

Evidence for selective advantage of pathogenic FGFR2 mutations in the male germ line

Observed mutation rates in humans appear higher in male than female gametes and often increase with paternal age. This bias, usually attributed to the accumulation of replication errors or inefficient repair processes, has been difficult to study directly. Here, we describe a sensitive method to quantify substitutions at nucleotide 755 of the fibroblast growth factor receptor 2 (FGFR2) gene in sperm. Although substitution levels increase with age, we show that even high levels originate from infrequent mutational events. We propose that these FGFR2 mutations, although harmful to embryonic development, are paradoxically enriched because they confer a selective advantage to the spermatogonial cells in which they arise.     

Insects – a mistake in God's creation? Tharu farmers' perception and knowledge of insects: A case study of Gobardiha Village Development Committee, Dang-Deukhuri, Nepal

Recent trends in agriculturalresearch and development emphasize the need forfarmer participation. Participation not onlymeans farmers' physical presence but also theuse of their knowledge and expertise.Understanding potentials and drawbacks of theirlocal knowledge system is a prerequisite forconstructive collaboration between farmers,scientists, and extension services.An ethnoentomological study, conducted in aTharu village in Nepal, documents farmers'qualitative and quantitative knowledge as wellas perceptions of insects and pest management,insect nomenclature and classification, andissues related to insect recognition and localbeliefs. The study offers a basis to improvepest management programs in terms of efficacyand acceptance. It demonstrates, for instance,that a concept of pests and beneficials isvirtually missing in traditional farmingcommunities and that the Tharu folkclassification profoundly differs from thescientific classification, but is not radicallydifferent from other folk entomologicalsystems. Insects belong to the taxa calledkiraa consisting of arthropods andnon-arthropods that interact with humans. Theyare classified in several overlappinghierarchies where locomotion and human impactplay major roles while morphological criteriaare almost irrelevant. Recognition ofkiraa, however, is dominated by agriculturalaspects followed by physiological-behavioral,ecological, and human-directed features.Morphological criteria play a minor role. Innomenclature, however, the insects' physicalappearance is more important than otherfeatures. The study further shows that male andfemale farmers have different perceptions ofkiraa.The insect-related knowledge system of theTharu has prevented farmers from using modernpesticides in the past. In the course ofmodernization, however, some aspects of theirknowledge system could become obsolete andprove disadvantageous to their livelihood andagro-ecosystems.     

Odor cues during slow-wave sleep prompt declarative memory consolidation

Sleep facilitates memory consolidation. A widely held model assumes that this is because newly encoded memories undergo covert reactivation during sleep. We cued new memories in humans during sleep by presenting an odor that had been presented as context during prior learning, and so showed that reactivation indeed causes memory consolidation during sleep. Re-exposure to the odor during slow-wave sleep (SWS) improved the retention of hippocampus-dependent declarative memories but not of hippocampus-independent procedural memories. Odor re-exposure was ineffective during rapid eye movement sleep or wakefulness or when the odor had been omitted during prior learning. Concurring with these findings, functional magnetic resonance imaging revealed significant hippocampal activation in response to odor re-exposure during SWS.     

Protein quality and digestible energy of selected foods determined in balance trials with rats

Chemical analyses and balance trials with rats of 17 foods showed marked differences in protein quality. According to anin vitro procedure true protein digestibility was high (around 90%). The same was also the case for thein vivo values with the exception of two legumes, beans and chick peas, which were digested to a markedly lower degree when compared to thein vitro values. The assumed reason for this is discussed. Due to extensive differences in the amino acid composition of the 17 samples BV varied considerably with the lowest value (45.5) of rice-wheat gluten breakfast cereal. Energy digestibility was generally high. Amino acid digestibility determinedin vivo followed the pattern of the corresponding protein digestibility, although marked differences occurred from one amino acid to another in the same food.     

Effects of high temperature on the growth of European whitefish (Coregonus lavaretus L.)

The effect of three different temperatures on growth in a first progeny generation, hatchery reared, subarctic population of European whitefish (Coregonus lavaretus L.) were investigated. The whitefish (start weight 444 g, ±SD 125 g) were reared for 60 days at three constant temperatures; 15, 18 and 21°C and under ambient light regimes for 70°N latitude. The results showed that temperature had a significant influence on the growth of the fish with the highest increase in weight increment occurring at 18°C (mean final weight 656 g ± SD 151 g) compared with the growth of fish held at 15°C (mean final weight 591 g ± SD 143 g) and 21°C (mean final weight 505 g ± SD 121 g). The cumulative per cent mortality of the fish during the experimental period increased with increasing temperature, from 10% at 15°C to 30% at 21°C. The present study indicates that the optimal temperature for farming of European whitefish is somewhere between 15 and 18°C rather than between 18 and 21°C.     

PrPSc spreading patterns in the brain of sheep linked to different prion types

ABSTRACT: Scrapie in sheep and goats has been known for more than 250 years and belongs nowadays to the so-called prion diseases that also include e.g. bovine spongiform encephalopathy in cattle (BSE) and Creutzfeldt-Jakob disease in humans. According to the prion hypothesis, the pathological isoform (PrPSc) of the cellular prion protein (PrPc) comprises the essential, if not exclusive, component of the transmissible agent. Currently, two types of scrapie disease are known - classical and atypical/Nor98 scrapie. In the present study we examine 24 cases of classical and 25 cases of atypical/Nor98 scrapie with the sensitive PET blot method and validate the results with conventional immunohistochemistry. The sequential detection of PrPSc aggregates in the CNS of classical scrapie sheep implies that after neuroinvasion a spread from spinal cord and obex to the cerebellum, diencephalon and frontal cortex via the rostral brainstem takes place. We categorize the spread of PrPSc into four stages: the CNS entry stage, the brainstem stage, the cruciate sulcus stage and finally the basal ganglia stage. Such a sequential development of PrPSc was not detectable upon analysis of the present atypical/Nor98 scrapie cases. PrPSc distribution in one case of atypical/Nor98 scrapie in a presumably early disease phase suggests that the spread of PrPSc aggregates starts in the di- or telencephalon. In addition to the spontaneous generation of PrPSc, an uptake of the infectious agent into the brain, that bypasses the brainstem and starts its accumulation in the thalamus, needs to be taken into consideration for atypical/Nor98 scrapie.