Möglichkeiten zur Förderung und zum Einsatz von Nützlingen an Stadtbäumen     

Barbara Jäckel  Hartmut Balder  Kristina Hasselmann 《Gesunde Pflanzen》2002,54(7):218-226

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Beziehungen zwischen Standort, Ern?hrungszustand und Wuchsleistung von Kiefernaufforstungen im Mittelmeergebiet     

W. Laatsch 《Forstwissenschaftliches Centralblatt》1967,86(2):69-81

Ohne Zusammenfassung  相似文献   

Die Entstehung von Lawinenbahnen im Hochlagenwald     

W. Laatsch 《European Journal of Forest Research》1977,96(1):89-93

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Wirksubstanzen der Pflanzenschutz- und Schädlingsbekämpfungsmittel     

Werner Perkow  Hartmut Ploss 《Journal of pest science》1996,69(1):10-10

Ohne Zusammenfassung  相似文献   

Typen der Massenverlagerung in den Alpen und ihre Klassifikation     

W. Laatsch  W. Grottenthaler 《European Journal of Forest Research》1972,91(1):309-339

Ohne Zusammenfassung  相似文献   

Zum 70. Geburtstag von Gustav A. Krau?     

W. Laatsch 《Forstwissenschaftliches Centralblatt》1958,77(3-4):124-125

Ohne Zusammenfassung  相似文献   

III. Buchbesprechungen     

E. Rohmeder  W. Laatsch  Mägdefrau  Huber  A. Bernhart  K. Rubner  Schwenke und H. Wiedemann 《Forstwissenschaftliches Centralblatt》1965,84(5-6):194-200

Ohne Zusammenfassung  相似文献   

Climate-forced variability of ocean hypoxia     

Deutsch C  Brix H  Ito T  Frenzel H  Thompson L 《Science (New York, N.Y.)》2011,333(6040):336-339

Oxygen (O(2)) is a critical constraint on marine ecosystems. As oceanic O(2) falls to hypoxic concentrations, habitability for aerobic organisms decreases rapidly. We show that the spatial extent of hypoxia is highly sensitive to small changes in the ocean's O(2) content, with maximum responses at suboxic concentrations where anaerobic metabolisms predominate. In model-based reconstructions of historical oxygen changes, the world's largest suboxic zone, in the Pacific Ocean, varies in size by a factor of 2. This is attributable to climate-driven changes in the depth of the tropical and subtropical thermocline that have multiplicative effects on respiration rates in low-O(2) water. The same mechanism yields even larger fluctuations in the rate of nitrogen removal by denitrification, creating a link between decadal climate oscillations and the nutrient limitation of marine photosynthesis.  相似文献   

Quantum spin hall insulator state in HgTe quantum wells   总被引：1，自引：0，他引：1  

König M  Wiedmann S  Brüne C  Roth A  Buhmann H  Molenkamp LW  Qi XL  Zhang SC 《Science (New York, N.Y.)》2007,318(5851):766-770

Recent theory predicted that the quantum spin Hall effect, a fundamentally new quantum state of matter that exists at zero external magnetic field, may be realized in HgTe/(Hg,Cd)Te quantum wells. We fabricated such sample structures with low density and high mobility in which we could tune, through an external gate voltage, the carrier conduction from n-type to p-type, passing through an insulating regime. For thin quantum wells with well width d < 6.3 nanometers, the insulating regime showed the conventional behavior of vanishingly small conductance at low temperature. However, for thicker quantum wells (d > 6.3 nanometers), the nominally insulating regime showed a plateau of residual conductance close to 2e(2)/h, where e is the electron charge and h is Planck's constant. The residual conductance was independent of the sample width, indicating that it is caused by edge states. Furthermore, the residual conductance was destroyed by a small external magnetic field. The quantum phase transition at the critical thickness, d = 6.3 nanometers, was also independently determined from the magnetic field-induced insulator-to-metal transition. These observations provide experimental evidence of the quantum spin Hall effect.  相似文献   

Isolation, characterization and antifungal activity of major constituents of the Himalayan lichen Parmelia reticulata Tayl     

Goel M  Dureja P  Rani A  Uniyal PL  Laatsch H 《Journal of agricultural and food chemistry》2011,59(6):2299-2307

Antifungal activity of hexane, ethyl acetate and methanol extracts of Parmelia reticulata was evaluated against soilborne pathogenic fungi, namely, Sclerotium rolfsii, Rhizoctonia solani, R. bataticola, Fusarium udum, Pythium aphanidermatum and P. debaryanum by poisoned food technique. Maximum antifungal activity was exhibited by hexane and ethyl acetate extracts against most of the test pathogens. Secondary metabolites, namely, (±)-isousnic acid, (±)-protolichesterinic acid, atranorin, evernyl, ethyl hematommate, ethyl orsellinate, methyl hematommate (3-formyl-2,4-dihydroxy-6-methylbenzoic acid methyl ester), 2-hydroxy-4-methoxy-3,6-dimethylbenzoic acid, 1-hydroxy-3,6-dimethoxy-8-methyl-xanthen-9-one, baeomycesic acid and salazinic acid, were isolated from the above extracts and identified by 1H NMR, 13C NMR and mass spectroscopic methods. When these metabolites were tested for antifungal activity against test pathogens, maximum antifungal activity was exhibited by (±)-protolichesterinic acid against R. solani (ED50=23.09 μg mL(-1)) and P. debaryanum (ED50=16.07 μg mL(-1)) and by atranorin against S. rolfsii (ED50=39.70 μg mL(-1)). The antifungal activity of protolichesterinic acid was found to be comparable to that of hexaconazole, a commercial fungicide.  相似文献