Interchange Slip-Running Reconnection and Sweeping SEP Beams

We present a new model to explain how particles (solar energetic particles; SEPs), accelerated at a reconnection site that is not magnetically connected to the Earth, could eventually propagate along the well-connected open flux tube. Our model is based on the results of a low-beta resistive magnetohydrodynamics simulation of a three-dimensional line-tied and initially current-free bipole, that is embedded in a non-uniform open potential field. The topology of this configuration is that of an asymmetric coronal null-point, with a closed fan surface and an open outer spine. When driven by slow photospheric shearing motions, field lines, initially fully anchored below the fan dome, reconnect at the null point, and jump to the open magnetic domain. This is the standard interchange mode as sketched and calculated in 2D. The key result in 3D is that, reconnected open field lines located in the vicinity of the outer spine, keep reconnecting continuously, across an open quasi-separatrix layer, as previously identified for non-open-null-point reconnection. The apparent slipping motion of these field lines leads to form an extended narrow magnetic flux tube at high altitude. Because of the slip-running reconnection, we conjecture that if energetic particles would be traveling through, or be accelerated inside, the diffusion region, they would be successively injected along continuously reconnecting field lines that are connected farther and farther from the spine. At the scale of the full Sun, owing to the super-radial expansion of field lines below 3 solar radii, such energetic particles could easily be injected in field lines slipping over significant distances, and could eventually reach the distant flux tube that is well-connected to the Earth

Aantal grondgebonden landbouwbedrijven kan alleen maar verder afnemen

Het aantal land- en tuinbouwbedrijven daalt al decennia lang. In 2002 waren er nog krap 90.000 bedrijven. Dat komt neer op een halvering sinds 1970. Die aanhoudende daling is een gevolg van het grote verschil tussen de (hoge) verkoopprijs van met namehet grondgebonden agrarische bedrijf en de (lage) waarde bij voortzetting van dat bedrijf als inkomensbron voor de ondernemer. Een analyse van het LE

Aantal grondgebonden landbouwbedrijven kan alleen verder dalen

Het aantal land- en tuinbouwbedrijven daalt al decennia lang. In 2003 zijn er, volgens voorlopige uitkomsten van de CBS- landbouwtelling, nog ruim 85.000 bedrijven. Die aanhoudende daling is onder meer een gevolg van het grote verschil tussen de verkoopprijs van het bedrijf en de waarde bij voortzetting van dat bedrijf als inkomensbron voor de ondernemer

Human enterobiasis in evolution: origin, specificity and transmission

The co-evolutionary pathway seems to be the most plausible hypothesis for the explanation of the origin of human pinworms. Of the two modes of transmission of oxyurids among humans which have been documented, the direct oral/anal route is also observed in other Primates and seems to have been favoured by selection. As indirect air-borne transmission has also been shown for human enterobiasis, the question of "How this alternative to the standard transmission method could have arisen" is examined. The results of comparative studies of prevalence of Enterobius in human coprolites, in villages of Neolithic age of the arid west of North America, show that a higher prevalence of pinworms is correlated with the lower total amount of air-exchange in caves relative to other structures. The air-borne route of transmission of pinworms among humans is interpreted as an innovation in the human/Enterobius pair. This mode of transfer could have been favoured during the time when humans changed their behaviour from a hunting-gathering to a more sedentary existence, initially associated with cave habitats

Analysis of Environmental Efficiency Variation

In this article, we develop and implement a methodology for analyzing the sources of variation in environmental efficiency across producers. We formulate a two-stage model. In the first stage, we use stochastic frontier analysis to estimate both technical and environmental efficiency. In the second stage, we again use stochastic frontier analysis to regress estimated environmental efficiency scores against a variety of technology, physical environment, and management variables. In this stage we estimate the impact of each explanatory variable on environmental efficiency, and we derive conditional estimates of environmental efficiency from the one-sided error component. We illustrate our methodology with an empirical application to a panel of Dutch dairy farms. We find evidence of relatively low levels of environmental efficiency, and we find that environmental efficiency can be improved through a number of policy options, including the provision of farmers with more insight into the nutrient balance of their farms. Copyright 2002, Oxford University Press.

The human beta-myosin heavy chain gene: Sequence diversity and functional characteristics of the protein

The {beta}-myosin heavy chain gene (MYH7) encodes the motor protein that drives myocardial contraction. It has been proven to be a disease gene for hypertrophic cardiomyopathy (HCM). We analyzed the DNA sequence variation of MYH7 (about 16 kb) of eight individuals: six patients with HCM and two healthy controls. The overall DNA sequence identity was up to 97.2% compared to Jaenicke and coworkers (Jaenicke et al. [1990] Genomics 8:194-206), while the corresponding amino acid sequences revealed 100% identity. In HCM patients, eleven nucleotide substitutions were identified but no causative disease mutation was found: six were detected in coding, four in intronic, and one in 5' regulatory regions. The average nucleotide diversity across this locus was 0.015% with an average of 0.02% in the coding and 0.012% in the noncoding sequence. Analysis of the kinetic behaviour of {beta}-MHC in the intact contractile structure of normal individuals and HCM patients revealed apparent rate constants of tension development ranging between 1.58 s-1 and 1.48 s-1