The effect of within-crop habitat manipulations on the conservation biological control of aphids in field-grown lettuce

Within-crop habitat manipulations have the potential to increase the biological control of pests in horticultural field crops. Wildflower strips have been shown to increase the abundance of natural enemies, but there is little evidence to date of an impact on pest populations. The aim of this study was to determine whether withincrop wildflower strips can increase the natural regulation of pests in horticultural field crops. Aphid numbers in plots of lettuce grown adjacent to wildflower strips were compared with those in plots grown in the absence of wildflowers. The presence of wildflower strips led to a decrease in aphid numbers on adjacent lettuce plants during June and July, but had less impact in August and September. The decrease in aphid numbers was greatest close to the wildflower strips and, the decrease in aphid numbers declined with increasing distance from the wildflower strips, with little effect at a distance of ten metres. The main natural enemies found in the crop were those that dispersed aerially, which is consistent with data from previous studies on cereal crops. Analysis and interpretation of natural enemy numbers was difficult due to low recovery of natural enemies, and the numbers appeared to follow changes in aphid abundance rather than being directly linked to the presence of wildflower strips. Cutting the wildflower strips, to remove floral resources, had no impact on the reduction in aphid numbers achieved during June and July, but decreased the effect of the wildflower strips during August and September. The results suggest that wildflower strips can lead to increased natural regulation of pest aphids in outdoor lettuce crops, but more research is required to determine how this is mediated by natural enemies and how the impact of wildflower strips on natural pest regulation changes during the growing season

Paisaje Vegetal y Espectro Ecológico de dos Municipios Navarros (España)

Tomando como referencia el trabajo de BRAUN BLANQUET y 0. DE BOLOS (1957) sobre el Valle del Ebro, se ha realizado un estudio del paisaje vegetal de Marcilla y Milagro, municipios situados en la Ribera de Navarra. Hemos reconocido comunidades vegetales pertenecientes a 14 clases fitosociológicas. Expresamos nuestros resultados mediante dos perfiles fitotopográficos y un espectro ecológico

Dynamic rotor mode in antiferromagnetic nanoparticles

We present experimental, numerical, and theoretical evidence for a new mode of antiferromagnetic dynamics in nanoparticles. Elastic neutron scattering experiments on 8 nm particles of hematite display a loss of diffraction intensity with temperature, the intensity vanishing around 150 K. However, the signal from inelastic neutron scattering remains above that temperature, indicating a magnetic system in constant motion. In addition, the precession frequency of the inelastic magnetic signal shows an increase above 100 K. Numerical Langevin simulations of spin dynamics reproduce all measured neutron data and reveal that thermally activated spin canting gives rise to a new type of coherent magnetic precession mode. This "rotor" mode can be seen as a high-temperature version of superparamagnetism and is driven by exchange interactions between the two magnetic sublattices. The frequency of the rotor mode behaves in fair agreement with a simple analytical model, based on a high temperature approximation of the generally accepted Hamiltonian of the system. The extracted model parameters, as the magnetic interaction and the axial anisotropy, are in excellent agreement with results from Mossbauer spectroscopy

Transcriptomic and epigenetic responses to short-term nutrient-exercise stress in humans

Abstract High fat feeding impairs skeletal muscle metabolic flexibility and induces insulin resistance, whereas exercise training exerts positive effects on substrate handling and improves insulin sensitivity. To identify the genomic mechanisms by which exercise ameliorates some of the deleterious effects of high fat feeding, we investigated the transcriptional and epigenetic response of human skeletal muscle to 9 days of a high-fat diet (HFD) alone (Sed-HFD) or in combination with resistance exercise (Ex-HFD), using genome-wide profiling of gene expression and DNA methylation. HFD markedly induced expression of immune and inflammatory genes, which was not attenuated by Ex. Conversely, Ex markedly remodelled expression of genes associated with muscle growth and structure. We detected marked DNA methylation changes following HFD alone and in combination with Ex. Among the genes that showed a significant association between DNA methylation and gene expression changes were PYGM, which was epigenetically regulated in both groups, and ANGPTL4, which was regulated only following Ex. In conclusion, while short-term Ex did not prevent a HFD-induced inflammatory response, it provoked a genomic response that may protect skeletal muscle from atrophy. These epigenetic adaptations provide mechanistic insight into the gene-specific regulation of inflammatory and metabolic processes in human skeletal muscle