In studies on the partitioning of resources, one issue which has been largely neglected is the change in feeding habits based on the availability of food in the environment, an aspect which is dealt with here with regard to the ichthyofauna of a tropical stream. Feeding preference was analyzed for eight species of fish which consumed high percentages of aquatic insects, based on a collection of fish and invertebrates during both the dry season (June 2006) and the wet season (December 2006) and in two different stretches of the stream, one of which shaded by gallery forest (“closed area”) and the other just bordered by herbaceous vegetation (“open area”). Based on a quantitative analysis of the composition of the benthic fauna and the diet of the ichthyofauna, the electivity index was calculated in order to assess potential alterations in the feeding preferences in line with seasonal and spatial modifications to the structure of the habitat and the supply of food. The analysis of the abundance of aquatic insects in the environment showed a predominance of Ephemeroptera in all situations analyzed (areas and seasons), with this insect group being the food item preferred by the majority of fish. However, space-time variations were observed in prey selection by the ichthyofauna. The analysis of supply, consumption and preference demonstrated somewhat varied situations for the majority of species, with both high and low selectivity for items consumed in low and high percentages, with the preferred item varying both spatially and seasonally. The sole exception to this was Phalloceros harpagos, choosing Diptera-Chironomidae in all the situations analyzed.
In this paper geodesically corresponding metricsg and
on a manifoldM, dim ≥5, under the assumption that the tensorsR andS of the metricg satisfyR.R=Q(S, R), are considered. It is stated that the corresponding tensors
not necessarily must satisfy
. Certain relations between the curvatures ofg and
Authors:Denis N. Jumbam, Ryan A. Skilton, Andrew J. Parrott, Richard A. Bourne, and Martyn Poliakoff
This paper describes the next stage in our development of self-optimising reactors. We demonstrate that the same reaction can be optimised for a series of different criteria including yield, space–time yield, E factor and a weighted yield function (the product of space–time yield and yield). In different experiments, we achieved 97.6% yield, space–time yield of 42.9 kg/L/h and E factors of 1.4 and 3.3 (including CO2) and the weighted yield, which gave a promising balance between yield, E factor and space–time yield.
A high efficiency BGO detecting system coupled to a coolant pumping device was used to monitor on-line the 6.13 MeV high energy gamma-ray, which is emitted from the 7.1 s half-life of16N activated by16O(n, p) reaction in a nuclear reactor. The system has been demonstrated effectively to monitor the real-time reactor power level as well as the space-time neutron flux distribution in reactor coolant.
The signal processing of the experimental output produced by simultaneous injection of two liquids in a flow microcalorimeter
allows, besides the determination of the mixture energy, to obtain information about the mixture thermokinetics. Starting
from this information, a model of space-time behaviour of the mixture dissipation is proposed. The simulations carried out
explain that an increase of the injection flow produces an increase in the dissipation length which could be located out of
the detection zone.
The propagation of an ultra-short light pulse is studied in the framework of scalar diffraction theory. Light pulses are focused by different types of wavy parabolic surfaces. The temporal-spatial behavior of the two-dimensional wave field is computed in the vicinity of the focal plane. It is shown that the slightly perturbation from the perfect parabolic shape leads a space-time dispersion of the pulse in the neighborhood of the focus.
Authors:René Becker, Sebastiaan (Bas) A.M.W. van den Broek, Pieter J. Nieuwland, Kaspar Koch, and Floris P.J.T. Rutjes
To expand the knowledge base for fundamental organic reactions in continuous flow, the α-bromination of acetophenone was successfully transformed from a known batch procedure to a continuous flow process in 99 % yield through D-optimal optimisation and subsequent scale-up of the validated optimum. Using a preparative scale system, a space–time yield of 0.26 kg/m3/s (comparable literature batch reaction 0.24 kg/m3/s) was achieved under conditions suitable for laboratory and small-scale industrial application where high yield or purity is required, e.g., when expensive substrates are used.
Two types of connections exist between cosmology and geophysics: any fundamental law of physics is incomplete without reference to initial and boundary conditions. That is true both for laboratory physics and for any cosmological physics a fortiori. The new ideas in cosmology, relativity and unitary field theory, show strong connections between the laws of elementary particle physics and space-time structure of the Universe. These connections give us new insight into the old ideas of Eddington and Ertel among others about cosmology and atom physics. The initial conditions which are resulting from the evolution and from the hot original state of the Universe, are also very important for the history of the Earth. On the other hand, geophysical research into the history of the Earth gives us information about “self-experienced” cosmology and about the proper history of physical laws and constants.
In this paper, the idea of an objective scale axis enriching Nature with a new dimension is explicated and illustrated on
the problem of heat conduction. Physical description of Nature thus has to be formulated on individual scale levels parametrized
by points of the scale axis), space and time are intrinsic parameters of each level. A ‘global’space-time then becomes a useful
construction expressing a possibility of a scale-independent description. Consequently, the cases in which such a description
is not possible (e.g. the problem of thermal waves) might lead to a contradiction with the concept of a global space-time,
which may manifest itself by a presence of some fractal structures.