Radio and plasma wave observations at Saturn from Cassini's approach and first orbit

We report data from the Cassini radio and plasma wave instrument during the approach and first orbit at Saturn. During the approach, radio emissions from Saturn showed that the radio rotation period is now 10 hours 45 minutes 45 +/- 36 seconds, about 6 minutes longer than measured by Voyager in 1980 to 1981. In addition, many intense impulsive radio signals were detected from Saturn lightning during the approach and first orbit. Some of these have been linked to storm systems observed by the Cassini imaging instrument. Within the magnetosphere, whistler-mode auroral hiss emissions were observed near the rings, suggesting that a strong electrodynamic interaction is occurring in or near the rings.     

Solution structure of the glucocorticoid receptor DNA-binding domain

The three-dimensional structure of the DNA-binding domain (DBD) of the glucocorticoid receptor has been determined by nuclear magnetic resonance spectroscopy and distance geometry. The structure of a 71-residue protein fragment containing two "zinc finger" domains is based on a large set of proton-proton distances derived from nuclear Overhauser enhancement spectra, hydrogen bonds in previously identified secondary structure elements, and coordination of two zinc atoms by conserved cysteine residues. The DBD is found to consist of a globular body from which the finger regions extend. A model of the dimeric complex between the DBD and the glucocorticoid response element is proposed. The model is consistent with previous results indicating that specific amino acid residues of the DBD are involved in protein-DNA and protein-protein interactions.     

Subdiffraction multicolor imaging of the nuclear periphery with 3D structured illumination microscopy

Fluorescence light microscopy allows multicolor visualization of cellular components with high specificity, but its utility has until recently been constrained by the intrinsic limit of spatial resolution. We applied three-dimensional structured illumination microscopy (3D-SIM) to circumvent this limit and to study the mammalian nucleus. By simultaneously imaging chromatin, nuclear lamina, and the nuclear pore complex (NPC), we observed several features that escape detection by conventional microscopy. We could resolve single NPCs that colocalized with channels in the lamin network and peripheral heterochromatin. We could differentially localize distinct NPC components and detect double-layered invaginations of the nuclear envelope in prophase as previously seen only by electron microscopy. Multicolor 3D-SIM opens new and facile possibilities to analyze subcellular structures beyond the diffraction limit of the emitted light.     

Reconstruction of Current Flow and Imaging of Current-Limiting Defects in Polycrystalline Superconducting Films

Magneto-optical imaging was used to visualize the inhomogeneous penetration of magnetic flux into polycrystalline TlBa2Ca2Cu3Ox films with high critical current densities, to reconstruct the local two-dimensional supercurrent flow patterns and to correlate inhomogeneities in this flow with the local crystallographic misorientation. The films have almost perfect c-axis alignment and considerable local a- and b-axis texture because the grains tend to form colonies with only slightly misaligned a and b axes. Current flows freely over these low-angle grain boundaries but is strongly reduced at intermittent colony boundaries of high misorientation. The local (<10-micrometer scale) critical current density Jc varies widely, being up to 10 times as great as the transport Jc (scale of approximately 1 millimeter), which itself varies by a factor of about 5 in different sections of the film. The combined experiments show that the magnitude of the transport Jc is largely determined by a few high-angle boundaries.     

Brassica sect.Brassica (Brassicaceae)

Summary An extensive crossing program including 10 wild taxa and 23 accessions representing 6 major cultivated forms and landraces of theBrassica oleracea group was carried out. Data for crossability, germination, viability, fertility inF ₁ andF ₂ were studied as well as the meiotic chromosomal pairing inF ₁ hybrids in some combinations. The fertility of hybrids between all cultivated forms and wild populations ofB. oleracea was high and it was concluded that all, including the Chinese endemicalboglabra form, belong to the same biological species. Among the other species,B. macrocarpa, B. montana, andB. rupestris had the lowest andB. cretica the highest fertility values in crosses with cultivated forms. The crossing data do not give any further information as to the genetic differentiation ofB. oleracea during the course of domestication. Introgression between wild and cultivated forms has probably occurred frequently. All members of theB. oleracea cytodeme belong to the primary and secondary gene pools of the 18 chromosomic crops and are as such of great importance for breeding purposes.     

Classification of apple scab resistance in two assortment orchards

The susceptibility to apple scab was evaluated in two assortment orchards in Southern Sweden, Alnarp (339 cultivars) and Balsgård (165). A scab index ranging from 0 to 4 was used and one assessment per tree was made annually from 1998 to 2000 on leaves. At Alnarp, the fruit scab was also evaluated. The over-all mean for the leaf scab index was highest at Alnarp (3.0) in 1999 when 55% of the cultivars were placed in fruit scab index 4, indicating severe scab infections. In 2000, the majority of the cultivars was grouped in classes 2 and 1. In 2000, 60.4% of the cultivars were placed in class 0, without any visible scab symptoms on the fruit. The leaf scab appeared to have a negative effect on fruit setting, since we found a lower number of cultivars bearing fruit when leaf scab index was high. The correlation between leaf and fruit scab was stronger during the first two years with high scab incidence. The most resistant cultivars or selections at Alnarp were Priscilla, Nova Easygro, Prima, Warner's King, Akane, Remo, Co-op 25, Liberty, McShay and Katinka. The over-all scab index mean at Balsgård was higher in 1998 (2.0) and 1999 (1.8) compared to 2000 (0.95). The best cultivars or selections at Balsgård were Co-op 22, Enterprise, McShay, Prima, Priscilla, William's Pride, Luke, Apelsinoe and Judeline.     

Effect of regeneration procedures on genetic diversity in Brassica napus and B. rapa as estimated by isozyme analysis

This investigation was conducted to assess changes in the genetic structure of two varieties of two species of annual Brassica. Seeds of B. napus cv. Topas and B. rapa Broccoletto were sent to nine research institutes in different geographical areas of Europe for regeneration. The multiplied material was sent back after one year of regeneration and analysed electrophoretically. The original populations of each species and their multiplied samples were stained for 12 different enzymes, of which 4 were found to be polymorphic (DIA, SKD, GPI and PER). It was possible to detect considerable differences in isozyme patterns in B. napus and allelic frequencies in B. rapa, both within and between populations. When the original population was compared with the regenerated samples, the Chi-square homogeneity test for all pairwise comparisons revealed distinctness with a 99% probability for B. napus and 95% probability for B. rapa with one or more of the enzyme systems examined. Furthermore, the average of gene diversity analysis (Nei, 1973) revealed that some regenerated populations have less while others have increased genetic variation compared with the original population. These observations indicated that the frequencies were non-random and considerable shifts in genetic diversity have occurred during multiplication. In addition, different regeneration procedures have caused the fixation of certain alleles.     

Modelling competitive anion adsorption on oxide minerals and an allophane-containing soil

Can surface complexation constants for anions, drawn from the literature for reference oxides, be combined to describe competitive adsorption in a spodic B horizon sample containing the important adsorbent minerals proto‐imogolite allophane and ferrihydrite? To answer this and to derive complexation constants for the corresponding reference oxides, a CD‐MUSIC model was used, with arsenate as the sorbing ion. To minimize the interference from competing organic substances, a sample containing little organic matter was used. To describe the adsorption of added arsenate correctly, it was found that competitive interactions from sulphate, silicic acid and phosphate had to be considered. In the model, the specific surface area of singly coordinated AlOH groups of allophane, the sulphate surface complexation constant on allophane, and the total concentration of reactive silicic acid were fitted. All other parameters were fixed using reference oxide values. The results indicated that arsenate, phosphate and silicic acid formed stronger surface complexes on ferrihydrite than on gibbsite or allophane, whereas the reverse was true for sulphate. I conclude that the approach used should provide significant qualitative information on the competitive adsorptive interactions in soils. However, the approach may be impractical for routine simulations and predictions. This is partly due to the uncertainty of the assumption that the properties of allophane and ferrihydrite in real soils can be approximated by those of gibbsite and ferrihydrite synthesized in the laboratory. Another difficulty is that the adsorption of arsenate and phosphate might not reach equilibrium within the limited time of most experiments.