A new population of very high energy gamma-ray sources in the Milky Way

Very high energy gamma-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first sensitive survey of the inner part of the Milky Way with the High Energy Stereoscopic System (HESS) reveals a population of eight previously unknown firmly detected sources of very high energy gamma-rays. At least two have no known radio or x-ray counterpart and may be representative of a new class of "dark" nucleonic cosmic ray sources.     

A molecular dynamics simulation on the self-assembly of ABC triblock copolymers. 2. Effects of block sequence

The effect of block sequence on the self-assembly of ABC-type triblock copolymers in the ordered state is investigated using an isothermal-isobaric molecular dynamics simulation. The block sequence has an important effect on the morphology of ABC triblock copolymers. Different morphologies are observed depending on the block sequence as well as the block composition. The triblock copolymers with the volume fraction of 1:1:1 (f _A=f _B=f _C=0.33) show the three phase and four layered lamellar structures irrespective of the block sequence. The A₃₂B₁₆C₃₂ triblock copolymer withf _B=0.2 shows a morphology in which cylinders of midblock B are formed at the interface between A and C lamellae, whereas the morphology of triblock copolymer B₁₆C₃₂A₃₂ and C₃₂A₃₂B₁₆ show a cylindrical core-shell structure and a lamellar type morphology, respectively. The A₂₀B₄₀C₂₀ triblock copolymer with the block B as a major component shows a tricontinuous structure, whereas both B₄₀C₂₀A₂₀ and C₂₀A₂₀B₄₀ triblock copolymers exhibit the lamellar structures. When the block B has larger volume fraction withf _B=0.75, the matrix is composed of block B, and other two blocks A and C form spherical domains.     

In vitro antioxidant properties and phenolic composition of Salvia virgata Jacq. from Turkey

Antioxidant activities and phenolic compositions of the active fractions of Salvia virgata Jacq. (Lamiaceae) from Turkey were examined. The aerial part of S. virgata was extracted with different solvents in an order of increasing polarity such as hexane, ethyl acetate, methanol, and 50% aqueous methanol using a Soxhlet apparatus. Water extract was also prepared from S. virgata by reflux. All solvent fractions were investigated for their total phenolic contents, total flavonoids, flavonols, qualitative-quantitative compositions (by HPLC-PDA analysis), iron(III) reductive activities, free radical scavenging activities (using DPPH*), and effect upon linoleic acid peroxidation activities; also, the peroxidation level was determined by the TBA method. The results of activity tests given as IC50 values were estimated from nonlinear algorithm and compared with standards, viz., butylated hydroxytoluene, ascorbic acid, and gallic acid. Polar fractions were found to be more active for free radical activity whereas nonpolar fractions protected the peroxidation of linoleic acid. Rosmarinic acid was the most abundant component in the extracts, followed by caffeic acid and lutelin-7- O-glycoside.     

Reproductive performance of postpartum ewes treated with insulin or progesterone hormones in association with ram effect

The reproductive performance of postpartum Santa Inês (SI) and Morada Nova (MN) ewes treated with insulin or progesterone hormones in association with ram effect was evaluated. Ewes from SI (n = 69) and MN (n = 69) breeds were randomly allocated to three groups of each breed (T1—ram effect only; T2—ram effect + insulin; T3—ram effect + progesterone). Progesterone concentrations (ηg/ml; mean ± SD) before and after introduction of rams (n = 6) were 0.51 ± 0.22 and 3.78 ± 0.68 (T1), 0.65 ± 0.21 and 3.77 ± 0.78 (T2) and 0.52 ± 0.21 and 3.84 ± 0.84 (T3) in SI ewes and 0.74 ± 0.19 and 3.71 ± 0.56 (T1), 0.70 ± 0.21 and 3.79 ± 0.75 (T2) and 0.81 ± 0.14 and 3.87 ± 0.80 (T3) in MN ewes, respectively. Thus, lower progesterone concentrations were found before the introduction of rams (p < .05). After the introduction of rams, preovulatory peaks of LH (ηg/ml) occurred at 28 (T1), 44 (T2) and 48 (T3) hr in SI ewes and at 64 (T1), 40 (T2) and 44 (T3) hr in MN ewes. The mean number of ovulations was similar between groups (p > .05), was 1.3 ± 0.51 (T1), 1.5 ± 0.54 (T2) and 1.6 ± 0.51 (T3) in SI ewes and 1.3 ± 0.51 (T1), 1.6 ± 0.51 (T2) and 1.6 ± 0.51 (T3) in MN ewes. In conclusion, the ram effect alone is effective at inducing and synchronizing oestrus in sheep under postpartum anoestrus, irrespective of hormone treatments.     

Liming alters body size distribution in a community of epigeic spiders in birch forest (<Emphasis Type="Italic">Betula pendula</Emphasis> Roth)

Key message

Liming, an ameliorative method for acidified forest soils, affected the relative abundance of prey of ground-hunting spiders and consequently reduced densities of functionally similar species of these predators.

Context

Liming, an ameliorative method for acidified forest soils, may modify the structure of an arthropod community by altering the soil characteristics and/or the availability of food resources.

Aims

We investigated the effect of liming on the community structure of ground-hunting spiders in a birch forest.

Methods

We established six experimental birch stand plots. Each stand was exposed to one of three experimental treatments: control, 1.5 t/ha, or 3 t/ha of dolomitic limestone. We collected spiders using pitfall traps during 5 years. We characterized the community in terms of activity density, species richness, community-weighted mean body size, and functional diversity and evenness in body size. We further investigated the potential links through which the liming might affect spiders, namely soil characteristics, effect of liming on birch, and densities of potential prey.

Results

The commonly used dosage of 3 t/ha reduced densities of functionally similar species which led to the reduced functional evenness in body size and increased functional divergence in body size. Liming increased soil pH only slightly but decreased the densities of spiders’ preferred prey.

Conclusion

The liming affected the community of ground-hunting spiders, at least partially, through reduced densities of their preferred prey.