Very-high-energy gamma rays from a distant quasar: how transparent is the universe?

The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.     

Lévy walks evolve through interaction between movement and environmental complexity

Ecological theory predicts that animal movement is shaped by its efficiency of resource acquisition. Focusing solely on efficiency, however, ignores the fact that animal activity can affect resource availability and distribution. Here, we show that feedback between individual behavior and environmental complexity can explain movement strategies in mussels. Specifically, experiments show that mussels use a Lévy walk during the formation of spatially patterned beds, and models reveal that this Lévy movement accelerates pattern formation. The emergent patterning in mussel beds, in turn, improves individual fitness. These results suggest that Lévy walks evolved as a result of the selective advantage conferred by autonomously generated, emergent spatial patterns in mussel beds. Our results emphasize that an interaction between individual selection and habitat complexity shapes animal movement in natural systems.     

Molecular phylogeny and species identification of sardines

The DNA sequence diversity of Sardina pilchardus (Walbaum, 1792) and some closely related species of Clupeomorpha was investigated using the mitochondrial DNA gene encoding cytochrome b. The nucleotide sequences of complete and partial mtDNA cytochrome b were determined in numerous specimens. Sequence divergence between species and genera was evenly distributed in the cytochrome b gene but rather high compared to reports for other fish species. Phylogenetic analyses on complete cytochrome b were used to study the relationships among the considered species. S. pilchardus was easily differentiated, showing a genetic distance of 0.25 with respect to Clupeidae species and 0.26 with respect to the other species. A species-specific short fragment (<150 bp) was isolated by polymerase chain reaction (PCR) using primers designed for Clupeomorpha. A rapid and reliable PCR method using restriction fragment length polymorphism (RFLP) with two restriction enzymes (MnlI/HinfI) was optimized for unambiguous differentiation of S. pilchardus from the other species tested (raw and canned products).     

Oleosins of Arabidopsis thaliana: expression in Escherichia coli, purification, and functional properties

The interfacial behavior of oleosins, the most abundant proteins from seeds oil bodies, was investigated using the pendant drop method at water/oil interfaces and compared to the behavior of beta-casein and lysozyme, proteins with contrasted emulsifying properties. Recombined high (rS3) and low (rS4) molecular weight oleosins comprising N-terminal histidine tags were purified to electrophoretic homogeneity. rS3 decreased the interfacial tension at the oil/water interface better than rS4, oleosins being more efficient than beta-casein. Oleosins formed aggregates when spread on noncompressed phospholipid (PL) films at the air/water interface as observed using a Langmuir-Blodgett balance equipped with a Brewster angle microscope. Oleosin spread at the surface of a compressed PL monolayer (5-20 mN/m) did not aggregate. Pressure increased immediately and proportionally to the amount of protein spread on the monolayer. The results stress the capacity of oleosins to be inserted in oil and in PL monolayers, which is of particular relevancy to their potential uses as water/oil emulsifiers.     

Antimicrobial and antioxidant effects of milk protein-based film containing essential oils for the preservation of whole beef muscle

Milk protein-based edible films containing 1.0% (w/v) oregano, 1.0% (w/v) pimento, or 1.0% oregano-pimento (1:1) essential oils mix were applied on beef muscle slices to control the growth of pathogenic bacteria and increase the shelf life during storage at 4 degrees C. Meat and film were periodically tested during 7 days for microbial and biochemical analysis. The lipid oxidation potential of meat was evaluated by the determination of thiobarbituric reactive substances (TBARS). The availability of phenolic compounds from essential oils was evaluated by the determination of total phenolic compounds present in the films during storage. Antioxidant properties of films during storage were also evaluated following a modified procedure of the N,N-diethyl-p-phenylenediamine colorimetric method. Oregano-based films stabilized lipid oxidation in beef muscle samples, whereas pimento-based films presented the highest antioxidant activity. The application of bioactive films on meat surfaces containing 10(3) colony-forming units/cm2 of Escherichia coli O157:H7 or Pseudomonas spp. showed that film containing oregano was the most effective against both bacteria, whereas film containing pimento oils seems to be the least effective against these two bacteria. A 0.95 log reduction of Pseudomonas spp. level, as compared to samples without film, was observed at the end of storage in the presence of films containing oregano extracts. A 1.12 log reduction of E. coli O157:H7 level was noted in samples coated with oregano-based films.     

Effects of retirement on lifestyle in relation to changes in weight and waist circumference in Dutch men: a prospective study

OBJECTIVE: To study changes in lifestyle in relation to changes in body weight and waist circumference associated with occupational retirement in men. DESIGN: A prospective cohort study with 5 years of follow-up. At baseline and at follow-up, questionnaires were completed and body weight and waist circumference were measured. SETTING: The Doetinchem Cohort Study, consisting of inhabitants of Doetinchem, a town in a rural area of The Netherlands.Subjects: In total 288 healthy men aged 50-65 years at baseline, who either remained employed or retired over follow-up. RESULTS: The effect of retirement on changes in weight and waist circumference was dependent on type of former occupation. Increase in body weight and waist circumference was higher among men who retired from active jobs (0.42 kg year(-1) and 0.77 cm year(-1), respectively) than among men who retired from sedentary jobs (0.08 kg year(-1) and 0.23 cm year(-1), respectively). Weight gain and increase in waist circumference were associated with a decrease in fruit consumption and fibre density of the diet, with an increase in frequency of eating breakfast, and with a decrease in several physical activities, such as household activities, bicycling, walking and doing odd jobs. CONCLUSION: Retirement was associated with an increase in weight and waist circumference among those with former active jobs, but not among those with former sedentary jobs. Retirement may bring opportunities for healthy changes in diet and physical activity, which could be used in health promotion programmes.     

Effects of conservation education on reasons to conserve biological diversity

To examine factors that might influence how people subscribe to different reasons for conserving biological diversity, we modified Ehrenfeld's [American Scientist 64 (1976) 660] classic reasons for conserving species and habitats into consumption, tourism, medicine, science, education, environmental baselines, ecosystem services, intrinsic value, and added another, human cultural heritage. We then explored the opinions of undergraduates enrolled in a classic conservation biology course, or a people and conservation course, about these nine arguments, using a 27-statement questionnaire. By matching responses made before and after each course, we found that students, in general, became more committed to using most of Ehrenfeld's arguments but that this was highly contingent on which conservation course that they had taken. None became committed to the argument that linked wildlife conservation to human culture, however. Course and grade that students attained influenced the extent to which students were sympathetic to different arguments but gender had no effect. These findings show that the type of conservation knowledge imparted to students makes them differentially sympathetic to many of the arguments used to advocate wildlife conservation.     

Chickpea evolution has selected for contrasting phenological mechanisms among different habitats

Arguably the most important adaptive criterion in annual crops is appropriate phenology that minimizes exposure to climatic stresses and maximizes productivity in target environments. To date this has been achieved empirically by selecting among diverse genotypes in target locations. This approach is likely to become inadequate with pending climate change because selection is imposed on the outcome (flowering time) rather than the underlying mechanism (i.e. responses to daylength, ambient or vernalizing temperatures). In contrast to the cereals, in legumes the interaction between phenological mechanisms and environmental selection pressure is largely unknown. This paper addresses this shortcoming through photothermal modelling of chickpea germplasm from the world’s key production areas using a meta-analysis of multi-environment trials located from 49° N to 35° S. Germplasm origin had significant effects on temperature and daylength responsiveness, the former strongly correlated to vegetative phase temperatures at the collection or development site (r = 0.8). Accordingly, temperature responses increase from winter- to spring-sown Mediterranean and Australian material, and then to north, central & southern India. Germplasm origin also affects the relationship between photoperiod and temperature response. In Eastern Mediterranean material a strong negative relationship (r = −0.77) enables temperature insensitive genotypes to compensate through a strong photoperiod response. Clearly, chickpea evolution has selected for different phenological mechanisms across the habitat range. Given that under the anticipated global warming temperature sensitive cultivars will flower relatively earlier than those responding largely to photoperiod, it is important to exploit this diversity in developing better-adapted genotypes for future cropping environments.     

Massenauftreten der Kleinen FichtenblattwespePristiphora abietina (Christ) im Hausruck

Zusammenfassung Das Massenauftreten der Kleinen FichtenblattwespePristiphora abietina (Christ) in Hausruck (OÖ) stellt wegen der hohen Intensität wie auch wegen des hartnäckigen Ausdauerns ein ernsthaftes Problem für die Forstwirtschaft in dieser Region dar. Dies ist um so bemerkenswerter als die Höhenstufe des Hausrucks (über 700m NN) für Gradationen dieses Forstschädlings bisher als ungeeignet galt.Wesentliche ökologische Faktoren wie Klima, Austriebsverhalten der Fichten, Aktivitätsdynamik der Blattwespen und Artenspektrum, die gewöhnlich Massenvermehrungen dieses Schädlings stark beeinflussen, wurden auf vier Standorten mit sehr unterschiedlichen Schadauftreten untersucht.Geringe kleinklimatische Unterschiede zwischen den Standorten wirkten sich auf das Austriebsverhalten und die Aktivitätsdynamik der Wespen in gleicher Weise aus, so daß sich stets eine gute Koinzidenz zwischen der Eiablagebereitschaft der Wespen und dem Vorhandensein von geeigneten Fichtentrieben ergab. Das Artenspektrum der Fichten-Nematinen im Untersuchungsgebiet umfaßt 11 Arten und war mit quantitativen Verschiebungen auf allen Unterschungsflächen dasselbe.Die stark unterschiedliche Intensität des Schadauftretens auf den verschiedenen Standorten ist somit aufgrund klimatologischer und koinzidenzbedingter Umstände sowie durch unterschiedliche Artendominanz nicht erkläbar. Dieser Umstand und die besondere immissionsökologische Situation des Untersuchungsgebietes machen einen Einfluß von Schadstoffeinträgen auf die Epidemiologie vonPr. abietina sehr wahrscheinlich.

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The mass outbreak of the Small Spruce SawflyPristiphora abietina (Christ) in the Hausruck I. Ecological conditions at an untypical gradation site

The high intensity and long persistance of the mass outbreak of the Small Spruce SawflyPristiphora abietina (Christ) in the Hausruck (Upper Austria) is a serious problem for forestry in this region. That is remarkable inasmuch as the altitudinal zone of the Hausruck (more than 700 m above sea level) up to now has been thought to be inappropriate for gradations of the Small Spruce Sawfly. Important ecological factors (climatic conditions, flushing time of the spruces, activity dynamics of the sawflies, species composition of the Nematini feeding on Norway spruce), usually influencing gradations of this insect pest, have been investigated at four sites, located close together but differing widely in intensity of the attack.There was a good coincidence between the sawflies' readiness for oviposition and the appropriate stage of development of the sprouts at all sites. So doubtless these factors are not the cause for the striking differences in the degree of injury within the research area.

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Mit 8 Abbildungen und 3 Tabellen