Sympathetic cooling route to Bose-Einstein condensate and Fermi-liquid mixtures

We discuss a sympathetic cooling strategy that can successfully mitigate fermion-hole heating in a dilute atomic Fermi-Bose mixture and access the temperature regime in which the fermions behave as a Fermi liquid. We introduce an energy-based formalism to describe the temperature dynamics with which we study a specific and promising mixture composed of 6Li and 87Rb. Analyzing the harmonically trapped mixture, we find that the favourable features of this mixture are further enhanced by using different trapping frequencies for the two species.Comment: 4 pages, 2 figure

Effecten van verwijderen vruchtmummies : blackrot in appel

Blackrot is een schimmelaantasting bij appels die recent in Nederland ontdekt is en afkomstig lijkt uit zuiderlijke landen. De schimmel overwintert onder meer op vruchtmummies en komt dan vooral voor op appelrassen die hun mummies lang vasthouden zoals Elstar. In een driejarig onderzoek is het effect van het verwijderen van de mummies als infectiebron op de aantasting bestudeerd. De resultaten zijn veelbelovend. Zo'n 60-90 procent afname van het aantal aangetaste appels bij de oogst

Dutch (organic) agriculture, carbon sequestration and energy production

Carbon sequestration in soils is often mentioned in the discussions about climate changes. In this paper the opportunities for carbon sequestration in Dutch agriculture are discussed at farm and national level. Farm internal carbon sources are already completely used in livestock farming. The effect under arable conditions is limited in time and very limited compared to national CO2 emission. External sources are scarce. Energy production out of crop residues and manure via biogas installations is possible but the overall impact is again very limited. The effect of this biogas pathway on soil organic matter quantity and quality is not yet known. Organic arable farmers do already have a higher soil organic matter content than conventional farmers, partly due to external carbon sources. This puts them in a leading position. The disadvantage is that it is more difficult for them to do a next step in increasing soil organic matte

Kali-vinasse tegen ascosporen vorming in conference blad : verslag van een éénjarig experiment

In a one year experiment under orchard conditions in an organic Conference orchard, a single treatment with 500 l/ha beetroot Vinasse was tested as a means to reduce the formation of ascospores in the over wintering leaves. Vinasse was applied with an orchard sprayer at the beginning of the leaf-fall period, diluted 1;1 with water. Directly after the completion of the leaf-fall large amounts of leaves were gathered in the orchard to be over wintered in wire mesh cages on the open ground. The fine wire mesh did not allow large earthworms to come in and take away the leaves. When ascospores were ripe in spring, samples were taken from these cages for the detection of ascospores. This was done using a water bath method after an incubation period in the laboratory. Vinasse applied in this way did not lead as expected to a reduction of the potential ascospore discharge but, on the contrary to an increase in ascospore discharge of 45%. This result differs from results in earlier trials. A satisfying explanation could not be found thus far. For the time being the leaf fall treatment with Vinasse against scab should be advised against

Degenerate fermion gas heating by hole creation

Loss processes that remove particles from an atom trap leave holes behind in the single particle distribution if the trapped gas is a degenerate fermion system. The appearance of holes increases the temperature and we show that the heating is (i) significant if the initial temperature is well below the Fermi temperature $T_{F}$, and (ii) increases the temperature to $T \geq T_{F}/4$ after half of the system's lifetime, regardless of the initial temperature. The hole heating has important consequences for the prospect of observing Cooper-pairing in atom traps.Comment: to be published in PR

The nucleon-sigma coupling constant in QCD Sum Rules

The external-field QCD Sum Rules method is used to evaluate the coupling constant of the light isoscalar-scalar meson (``$\sigma$'' or \epsilon) to the nucleon. The contributions that come from the excited nucleon states and the response of the continuum threshold to the external field are calculated. The obtained value of the coupling constant is compatible with the large value required in one-boson exchange potential models of the two-nucleon interaction.Comment: 11 pages, 4 figure

Phase separation of Bose-Einstein condensates

The zero-temperature system of two dilute overlapping Bose-Einstein condensates is unstable against long wavelength excitations if the interaction strength between the distinguishable bosons exceeds the geometric mean of the like-boson interaction strengths. If the condensates attract each other, the instability is similar to the instability of the negative scattering length condensates. If the condensates repel, they separate spatially into condensates of equal pressure. We estimate the boundary size, surface tension and energy of the phase separated condensate system and we discuss the implications for double condensates in atomic traps.Comment: 11 pages, 1 figur