An optical microcantilever with integrated grating coupler

[No abstract available

Nucleation of a sodium droplet on C60

We investigate theoretically the progressive coating of C60 by several sodium atoms. Density functional calculations using a nonlocal functional are performed for NaC60 and Na2C60 in various configurations. These data are used to construct an empirical atomistic model in order to treat larger sizes in a statistical and dynamical context. Fluctuating charges are incorporated to account for charge transfer between sodium and carbon atoms. By performing systematic global optimization in the size range 1<=n<=30, we find that Na_nC60 is homogeneously coated at small sizes, and that a growing droplet is formed above n=>8. The separate effects of single ionization and thermalization are also considered, as well as the changes due to a strong external electric field. The present results are discussed in the light of various experimental data.Comment: 17 pages, 10 figure

Cyclic voles and shrews and non-cyclic mice in a marginal grassland within European temperate forest

Cyclic population dynamics of small mammals are not restricted to the boreal and arctic zones of Eurasia and North America, but long-term data series from lower latitudes are still less common. We demonstrated here the presence of periodic oscillations in small mammal populations in eastern Poland using 22-year (1986–2007) trapping data from marginal meadow and river valley grasslands located in the extensive temperate woodland of Białowieża Primeval Forest. The two most common species inhabiting meadows and river valleys, root vole Microtus oeconomus and common shrew Sorex araneus, exhibited synchronous periodic changes, characterised by a 3-year time lag as indicated by an autocorrelation function. Moreover, the cycles of these two species were synchronous within both habitats. Population dynamics of the striped field mouse Apodemus agrarius was not cyclic. However, this species regularly reached maximum density 1 year before the synchronized peak of root voles and common shrews, which may suggest the existence of interspecific competition. Dynamics of all three species was dominated by direct density-dependent process, whereas delayed density dependent feedback was significant only in the root vole and common shrew. Climatic factors acting in winter and spring (affecting mainly survival and initial reproduction rates) were more important than those acting in summer and autumn and affected significantly only the common shrew. High temperatures in winter and spring had positive effects on autumn-to-autumn changes in abundance of this species, whereas deep snow in combination with high rainfall in spring negatively affected population increase rates in common shrew

The photophase light intensity does not affect the scotophase melatonin response in the domestic pig

Copyright © 2001 Elsevier Science B.V. All rights reserved.This study investigated the effects of the photophase light intensity on the scotophase melatonin response. Twelve, 8-month-old crossbred gilts were allocated to three groups of four and housed in temperature- and lighting-controlled climate rooms. The rooms had a light intensity of 40, 200 or 10,000 lx and a light-dark cycle of 12 L:12 D. The gilts were allowed to acclimatize to a new lighting regimen for 1 week before being sampled at 2h intervals for 24h. Following the sampling, pigs were transferred under a different light intensity, allowed to adjust for 1 week and sampled again. The procedure was repeated three times so that all the groups went through all three lighting regimens (light intensities). All the gilts exhibited a clear circadian serum melatonin rhythm under each lighting regimen with high melatonin concentrations occurring during the scotophase. There was no difference in the scotophase melatonin response in terms of mean concentrations or duration of increased melatonin levels within or between the groups under different lighting regimens. There was considerable inter-individual variation in the dark phase melatonin response but the individual profiles were consistent under the different lighting regimens. It is concluded that when a certain threshold light intensity (<40lx) is exceeded, the photophase light intensity has no effect on the scotophase melatonin response. These results imply that extremely high light intensities during the photophase would provide no additional benefits compared with normal comfortable light intensity, if artificial lighting programs were introduced to commercial piggeries in order to reduce seasonal effects on reproduction.Anssi Tast, Robert J. Love, Gareth Evans, Håkan Andersson, Olli A. T. Peltoniemi and David J. Kennawayhttp://www.elsevier.com/wps/find/journaldescription.cws_home/503300/description#descriptio

The pattern of melatonin secretion is rhythmic in the domestic pig and responds rapidly to changes in daylength

The aim of the study was to investigate the capability of pigs to respond to abrupt changes in lighting conditions by means of alterations in circadian melatonin profiles. Sixteen pre-pubertal crossbred male pigs weighing 40–45 kg were housed in individual pens in four temperature- and lighting-controlled climate rooms (four pigs per room). In two rooms there was a light–dark cycle of 16 L:8 D (Group A) and in two other rooms 8 L:16 D (Group B). Under both lighting regimens light intensity at pig eye-level was 220–240 lx during the light phase and less than 7 lx (red light) during the dark phase. The lighting regimens were changed after 2 wks to the opposite regimen and the change was repeated after a further 2 wks, so that animals ended up with the same light cycle with which they started. Blood was sampled at 2-hr intervals for 48 hr spanning each time of change in lighting. A further 24-hr sampling was performed at the end of the experiment (2 wks after the last change) in both groups and 1 wk after the change from short to long day lighting in Group A. On 83/86 occasions, pigs exhibited a clear circadian rhythm in plasma melatonin under both lighting regimens. Pigs responded immediately to the change from long to short day lighting by advancing melatonin secretion to the earlier lights-off time and some pigs were able to extend secretion to the delayed lights-on time. For short to long day changeover there was a small immediate response, with secretion pattern following the previously entrained endogenous rhythm to within 3 hr of the previous lights-on time. After 1 wk commencement of secretion was delayed by up to 2 hr, while after 2 wks some pigs were able to delay commencement of secretion until lights-off or to cease at lights-on. It is concluded that the domestic pig is able to commence adjustment to abrupt changes in photoperiod within a 1-wk acclimatization by altering circadian melatonin secretion. The present study suggests that it may be possible to use simplified lighting regimens instead of stepwise changing lighting programs in commercial piggeries to reduce the influence of season on production.Anssi Tast, Robert J. Love, Gareth Evans, Shevahn Telsfer, Roger Giles, Paul Nicholls, Athena Voultsios, David J. Kennawa