Enhancement of Superconductivity through Lattice Softening

The superconducting transition temperature of an iridium-yttrium eutectic is enhanced extraordinarily through lattice softening. This is shown by a drastically reduced Debye temperature.     

Rare-earth oxides of manganese and cobalt rival platinum for the treatment of carbon monoxide in auto exhaust

The perovskite-like compounds RE(1-X)Pb(5)MnO(3) and RECoO(3), where RE (rare earth) is lanthanum, praseodymium, or neodymium, are active catalysts for the oxidation of carbon monoxide. Crushed single crystals of these compounds compare favorably with commercial platinum catalysts in initial activity and lifetime. Therefore, these compounds are promising substitutes for platinum in devices for the catalytic treatment of auto exhaust.     

Superconducting phosphorus

Phosphorus, the element itself, becomes superconducting near 4.7 degrees K and at pressures exceeding 100 kilobars. This constitutes one of the four last missing links in the proof that superconductivity is normal behavior for every truly metallic sp element. The three remaining ones are arsenic, sulfur, and iodine.     

Rural economic development through local self-development strategies

During the 1980s many communities turned to grassroots activities to promote economic development, rather than relying on industrial recruitment strategies. We evaluate the characteristics of these projects, their benefits and costs, and obstacles they face in the development process. The data are drawn from a survey of more than one hundred communities in the United States. Self-development efforts do not appear to replace traditional rural economic development activities, but may complement them. Self-development activities produce a wide variety of jobs that are taken primarily by local residents. The cost and availability of credit are major obstacles for self-development projects. Although self-development strategies should not be considered the primary economic development strategy for most rural communities, they do enable communities to build a more viable local economy.     

Antimicrobial and Antibiofilm Activities of the Fungal Metabolites Isolated from the Marine Endophytes Epicoccum nigrum M13 and Alternaria alternata 13A

Epicotripeptin (1), a new cyclic tripeptide along with four known cyclic dipeptides (2–5) and one acetamide derivative (6) were isolated from seagrass-associated endophytic fungus Epicoccum nigrum M13 recovered from the Red Sea. Additionally, two new compounds, cyclodidepsipeptide phragamide A (7) and trioxobutanamide derivative phragamide B (8), together with eight known compounds (9–16), were isolated from plant-derived endophyte Alternaria alternata 13A collected from a saline lake of Wadi El Natrun depression in the Sahara Desert. The structures of the isolated compounds were determined based on the 1D and 2D NMR spectroscopic data, HRESIMS data, and a comparison with the reported literature. The absolute configurations of 1 and 7 were established by advanced Marfey’s and Mosher’s ester analyses. The antimicrobial screening indicated that seven of the tested compounds exhibited considerable (MIC range of 2.5–5 µg/mL) to moderate (10–20 µg/mL) antibacterial effect against the tested Gram-positive strains and moderate to weak (10–30 µg/mL) antibacterial effect against Gram-negative strains. Most of the compounds exhibited weak or no activity against the tested Gram-negative strains. On the other hand, four of the tested compounds showed considerable antibiofilm effects against biofilm forming Gram-positive and Gram-negative strains.     

Driving factors of temporal variation in agricultural soil respiration

Investigations of diurnal and seasonal variations in soil respiration support modeling of regional CO₂ budgets and therefore in estimating their potential contribution to greenhouse gases. This study quantifies temporal changes in soil respiration and their driving factors in grassland and arable soils located in Northern Germany. Field measurements at an arable site showed diurnal mean soil respiration rates between 67 and 99 mg CO₂ m^–2 h^–1 with a hysteresis effect following changes in mean soil temperatures. Field soil respiration peaked in April at 5767 mg CO₂ m^–2 day^–1, while values below 300 mg CO₂ m^–2 day^–1 were measured in wintertime. Laboratory incubations were carried out in dark open flow chambers at temperatures from 5°C to 40°C, with 5°C intervals, and soil moisture was controlled at 30%, 50%, and 70% of full water holding capacity. Respiration rates were higher in grassland soils than in arable soils when the incubating temperature exceeded 15°C. The respiration rate difference between them rose with increasing temperature. Monthly median values of incubated soil respiration rates ranged from 0 to 26.12 and 0 to 7.84 µg CO₂ g^–1 dry weight h^–1, respectively, in grassland and arable land. A shortage of available substrate leads to a temporal decline in soil respiration rates, as indicated by a decrease in dissolved organic carbon. Temporal Q₁₀ values decreased from about 4.0 to below 1.5 as temperatures increased in the field. Moreover, the results of our laboratory experiments confirmed that soil temperature is the main controlling factor for the Q₁₀ values. Within the temperature interval between 20°C and 30°C, Q₁₀ values were around 2 while the Q₁₀ values of arable soils were slightly lower compared to that of grassland soils. Thus, laboratory studies may underestimate temperature sensitivity of soil respiration, awareness for transforming laboratory data to field conditions must therefore be taken into account.     

Stoffkonzentrationen in bodenlösungen bei verschiedenen fruchtfolgen auf einem sandigen standort 2. mitteilung: Nitratverlagerung

In einem komplexen Feldversuch auf einem sandigen Standort wurde über einen Zeitraum von 5 Jahren in verschiedenen Fruchtfolgen die Wirkung unterschiedlicher Bodenbearbeitung und Mineral‐N‐Düngung auf die Nitratkonzentration in Bodenlösungen mit Hilfe einer Saugkerzenanlage untersucht. Die Nitratkonzentrationen in Bodenlösungen (60 cm Tiefe) wurden untersucht und die potentielle N‐Fracht auf der Grundlage der Nitratkonzentration im Bodenwasser und der klimatischen Wasserbilanz kalkuliert.

Die Nitratkonzentrationen in Bodenlösungen folgten einer ausgeprägten jahreszeitlichen Dynamik, mit Maxima in der Hauptsickerperiode und Minima in der Vegetationszeit, wobei die Wirkung der Prüffaktoren in folgender Reihenfolge abnahm: Mineral‐N‐Düngung > Fruchtfolge > Bodenbearbeitung.

In der Hauptsickerperiode wurde > 50% der jährlichen Sickerwassermenge und 36 . . . 94% der N‐Fracht ermittelt. Auf dem Untersuchungsstandort betrugen die maximalen N‐Frachten ca. 100 kg ha^?1a^?1.

Die N‐Frachten wurden durch die N‐Entzüge der verschiedenen Fruchtarten beeinflusst. Durch mineralische N‐Düngung stiegen die N‐Entzüge von Wintergetreide um 42 . . . 85% und von Silomais um 32 . . . 53%.