ALBERT

Notes: Voltage-modulated scanning force microscopy (Piezoresponse microscopy) is applied to investigate the domain structure in epitaxial PbZr0.2Ti0.8O3 ferroelectric thin films grown on (001) SrTiO3. By monitoring the vertical and lateral differential signals from the photodetector of the atomic force microscope it is possible to separate out and observe the out-of-plane and in-plane polarization vectors in the thin film individually. The relative orientation of the polarization vectors across a 90° domain wall is observed. Nucleation of new reversed 180° domains at the 90° domain wall is studied and its impact on the rotation of polarization within the a domain is analyzed as a function of reversal time. © 2002 American Institute of Physics.

Notes: In this letter, we report on the integration of epitaxial ferroelectric Pb(Zr, Ti)O3 (PZT) thin films on Si [100] substrates using a SrTiO3 (STO) template layer and a conducting perovskite (La0.5Sr0.5)CoO3 electrode. X-ray diffraction studies reveal both in-plane and out-of-plane alignment of the heterostructure. The epitaxial films show extremely high remnant polarization as well as piezoelectric d33 coefficients compared to textured and untextured polycrystalline films. © 2002 American Institute of Physics.

Notes: Juvenile Tilapia mossambica (Peters) are extremely tolerant of depth and can compensate to a depth increase of 0 to 33 m in a few minutes. As the fish grow they become less able to compensate to deep water. At a total length of 15–18.5 cm small adult male T. mossambica can compensate to 20 m whereas females can only compensate to 13 m. Large adults (20–25 cm) of both sexes compensated to 11.5 m (range 9.5–13 m). Adult fish require 4 to 7 days for maximum depth compensation at 22°C. Analysis of the oxygen content of the swimbladder indicated that this gas accounts for over half the gas in surface equilibrated fish. Oxygen secretion into the swimbladder appears to be the mechanism of equilibration at depth.

Notes: An epizootic in imported carp (Cyprinus carpio L.) was examined by bacteriological, viro-logical and histological methods. The microbiological investigations did not reveal the aetiology of the disease, but the histological description of the lesions is similar to that for carp erythrodermatitis ‘CE’.

Notes: The ability of adult Tilapia mossambica Peters to enter deep water was determined at 15, 22 and 30°C. At 30°C adults compensate to about 20m depth but at 15°C to only 7 m. Compensation is more rapid at high than at low temperatures. T. mossambica haemoglobin has a marked Root effect which is the same at 22 and 30°C. The oxygen affinity of the haemoglobin is higher at 15°C than at 30°C. There was no measurable difference in the rate of passive oxygen diffusion across the swimbladder wall in the temperature range 15–30°C. It is concluded that the ability to enter deeper water at higher temperatures is related to decreased oxygen affinity of the haemoglobin and higher rates of oxygen secretion and blood circulation.

Notes: Wild oat (Arena fatua L.) plants were dosed hydroponically with 14C-benzoylprop ethyl [ethyl N-benzoyl-N (3,4-dichlorophenyl)-2-aminopropionate] and were grown under different light and nutrient levels. Herbicide metabolism and growth inhibition in plant shoots were measured alter 3, 6, and 12 days. Plants under low light contained more benzoylprop acid due to increased de-esterification at 3 and 6 days, and decreased acid-conjugate formation at 12 days. When plants, were subjected to low nutrient levels, both metabolic reactions were slowed resulting in increased acid at 3 days, but not at 6 or 12 days. After 12 days, however, there was more growth inhibition at the low nutrient level. Growth correlated better to the amount (dpm) of acid-conjugate than to the amount of ester or acid in plant shoots. Acid concentration had the most influence on subsequent growth. It was concluded that although reduced light and nutrients result in higher levels of benzoylprop acid, increased benzoylprop ethyl efficacy is also due lo a reduced growth rate of the wild oat. This study supports observations that crop competition increases benzoylprop ethyl efficacy. Effets de la lumière et des niveaux des éléments nutritifs sur le métabolisme et l'effet inhibiteur sur la croissance du 14 C-benzoyl prop éthyle chez la folle avoine (Avena fatua L.)Des plantes de folle avoine (Avena fatua L.) en culture hydroponique ont été soumises à diverses doses de 14C-benzoylprop éthyle et à des niveaux différents d'éclairage et de nutrition. Le metabolisme de l'herbicide et l'inhibition de la croissance ont été measurés dans les jeunes pousses des plantes après 3.6 et 12 jours. Les plantes cultivées sous un faible eclairage contenaient plus d'acide benzoylprop dû a un accroissement de la dé-estérification á 3 et 6 jours et á une diminution de la formation du conjugué-acide á 12 jours. Lorsque les plantes ont été soumises à de bas niveaux de nutrition, les deux réactions métaboliques ont été ralenties, ce qui a provoqué un accroissement de l'acide à 3 jours, mais pus à 6 ou 12 jours. Toutefois, aprés 12 jours, l'inhibition de la croissance a été plus marquée au faible niveau de nutrition. La corrélation de la croissance a été meilleure avec le taux de conjugué-acide qu'avec celui d'esier ou d'acide dans les jeunes pouses des plantes. La concentration de l'acide a joué le rôle le plus important sur la croissance uliérieure. La conclusion est qu'en dépit du fait que la reduction de la lumiére et de la nutrition provoque de hauts niveaux d'acide benzoylprop. l'accroissement de l'efficacité du benzoylprop éthyl est également dû une reduction du taux de croissance de la folle avoinc. Cette étude rapporte des observations montrant que la compétition de la plante cultivée augmente l'efficacité du benzoylprop éthyle. Die Wirkung von Licht und Nährstoffversorgung auf den Abbau von 14 C-Benzoylprop-äthyl und auf die Wuchshemmung von Flughafer (Avena fatua L.)Flughaferpflanzen (Avena fatua L.) wurden über Wasserkultur mit 14C-Benzoylprop-äthyl [N-Benzoyl-N-(3,4-dichlorphenyl)-2-aminoproprionsäureäthylester] versorgt und bei unterschiedlicher Licht-und Nährstoffversorgung kultiviert. Es wurde der Herbizibabbau und die Wuchshemmung des Sprosses nach 3.6 und 12 Tagen gemesssen. Bei geringer Lichtintensität enthielten die Pflanzen am 3. und 6. Tag aufgrund verstärkter Verseifung mehr Benzoylprop-Säure, und am 12, Tag weniger Säure-Konjugat. Bei geringer Nährstoffversorgung Wurden beide Abbauprozesse verlangsamt, was eine Zunahme der Säure am 3. Tag, nicht aber am 6.und 12. Tag zur Folge hatte. Nach 12 Tagen war aber bei geringer Nährstoffver-sorgung die Wuchshemmung stärker. Die correlation zwischen Wachstum und Gehalt der Sprosse an Säure-Konjugat (dpm) war besser als mit dem Gehalt an Ester order Säure. Der Säurege-halt hatte die stäkste Wirkung auf das Wachstum. Aus den Ergebnissen wird geschlossen, dass obwohl eine reduzierte Licht- und Nährstoffversorgung höhere Gehalte an Benzoylprop-Säure bedingen, die Wirkung von Benzoylprop-äthyl auch durch das verminderte Wachstum des Flughafers bewirkt wird. Diese Untersuchungen unterstützen die Beobachtung, dass die Wirkung von Benzoylprop-äthyl durch die Konkurrenz der Kulturpflanzen verstärkt wird.