Statistisch onderzoek naar de samenhang tussen het weer, de grasproductie en de melkaanvoer

A study was made by calculating correlation and regression coefficients, and by rising frequency diagrams of the relation between the weather factors temperature (mean daily temp. taken from observations at 8,14 and 19 hours), cloudiness and number of days with at least I mm precipitation, and the production of grass (first cut in June) and the milk supply during June-September.Independent of soil and the differences in climatic circumstances, a reliable positive correlation was found between the grass production and the number of days with precipitation and cloudiness during the period 1 May-10 June. In this period there was a negative correlation with temperature. From data obtained from the western part of the Netherlands a reliable positive correlation was found with temperature during the winter.The milk supply during June-September was positively correlated with number of days with precipitation and cloudiness in the months July and August. The correlation with temperature in these months was negative.Reliable correlations were found in May in districts where grazing in the weeks before mowing caused risk. The correlations with cloudiness and precipitation were positive, while those with temperature were negative.Otherwise the correlations in May were unimportant as was expected.<p/

Invariant Classification and Limits of Maximally Superintegrable Systems in 3D

The invariant classification of superintegrable systems is reviewed and utilized to construct singular limits between the systems. It is shown, by construction, that all superintegrable systems on conformally flat, 3D complex Riemannian manifolds can be obtained from singular limits of a generic system on the sphere. By using the invariant classification, the limits are geometrically motivated in terms of transformations of roots of the classifying polynomials

A Statistical Approach to The Life Cycle Analysis of Cumulus Clouds Selected in A Virtual Reality Environment

In this study, a new method is developed to investigate the entire life cycle of shallow cumuli in large eddy simulations. Although trained observers have no problem in distinguishing the different life stages of a cloud, this process proves difficult to automate, because cloud-splitting and cloud-merging events complicate the distinction between a single system divided in several cloudy parts and two independent systems that collided. Because the human perception is well equipped to capture and to make sense of these time-dependent three-dimensional features, a combination of automated constraints and human inspection in a three-dimensional virtual reality environment is used to select clouds that are exemplary in their behavior throughout their entire life span. Three specific cases (ARM, BOMEX, and BOMEX without large-scale forcings) are analyzed in this way, and the considerable number of selected clouds warrants reliable statistics of cloud properties conditioned on the phase in their life cycle. The most dominant feature in this statistical life cycle analysis is the pulsating growth that is present throughout the entire lifetime of the cloud, independent of the case and of the large-scale forcings. The pulses are a self-sustained phenomenon, driven by a balance between buoyancy and horizontal convergence of dry air. The convective inhibition just above the cloud base plays a crucial role as a barrier for the cloud to overcome in its infancy stage, and as a buffer region later on, ensuring a steady supply of buoyancy into the cloud

General relativistic Sagnac formula revised

The Sagnac effect is a time or phase shift observed between two beams of light traveling in opposite directions in a rotating interferometer. We show that the standard description of this effect within the framework of general relativity misses the effect of deflection of light due to rotational inertial forces. We derive the necessary modification and demonstrate it through a detailed analysis of the square Sagnac interferometer rotating about its symmetry axis in Minkowski space-time. The role of the time shift in a Sagnac interferometer in the synchronization procedure of remote clocks as well as its analogy with the Aharanov-Bohm effect are revised.Comment: 11 pages, 3 figure