Life path analysis: scaling indicates priming effects of social and habitat factors on dispersal distances

1. Movements of many animals along a life-path can be separated into repetitive ones within home ranges and transitions between home ranges. We sought relationships of social and environmental factors with initiation and distance of transition movements in 114 buzzards Buteo buteo that were marked as nestlings with long-life radio tags. 2. Ex-natal dispersal movements of 51 buzzards in autumn were longer than for 30 later in their first year and than 35 extra-natal movements between home ranges after leaving nest areas. In the second and third springs, distances moved from winter focal points by birds that paired were the same or less than for unpaired birds. No post-nuptial movement exceeded 2 km. 3. Initiation of early ex-natal dispersal was enhanced by presence of many sibs, but also by lack of worm-rich loam soils. Distances travelled were greatest for birds from small broods and with relatively little short grass-feeding habitat near the nest. Later movements were generally enhanced by the absence of loam soils and short grassland, especially with abundance of other buzzards and probable poor feeding habitats (heathland, long grass). 4. Buzzards tended to persist in their first autumn where arable land was abundant, but subsequently showed a strong tendency to move from this habitat. 5. Factors that acted most strongly in ½-km buffers round nests, or round subsequent focal points, usually promoted movement compared with factors acting at a larger scale. Strong relationships between movement distances and environmental characteristics in ½-km buffers, especially during early ex-natal dispersal, suggested that buzzards became primed by these factors to travel far. 6. Movements were also farthest for buzzards that had already moved far from their natal nests, perhaps reflecting genetic predisposition, long-term priming or poor habitat beyond the study area

Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters

Search for electroweak production of single top quarks in ppˉp\bar{p} collisions.

We present a search for electroweak production of single top quarks in the electron+jets and muon+jets decay channels. The measurements use ~90 pb^-1 of data from Run 1 of the Fermilab Tevatron collider, collected at 1.8 TeV with the DZero detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process ppbar->tb+X of 39 pb. The upper limit for the t-channel process ppbar->tqb+X is 58 pb. (arXiv

Hard Single Diffraction in pbarp Collisions at root-s = 630 and 1800 GeV

Using the D0 detector, we have studied events produced in proton-antiproton collisions that contain large forward regions with very little energy deposition (``rapidity gaps'') and concurrent jet production at center-of-mass energies of root-s = 630 and 1800 Gev. The fractions of forward and central jet events associated with such rapidity gaps are measured and compared to predictions from Monte Carlo models. For hard diffractive candidate events, we use the calorimeter to extract the fractional momentum loss of the scattered protons.Comment: 11 pages 4 figures. submitted to PR

The giant spiral galaxy M 101 - Radio observations of H II regions in external galaxies. II - Radio continuum emission from the H II regions and the nonthermal disc of M 101

Wetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe

The molecular epidemiology of tuberculosis in inner London

Peer reviewedFinal Accepted Versio

Tested method to minimize plutonium assay discrepancies between laboratories

Plutonium assay differences are frequently observed between laboratories exchanging plutonium dioxide powders. These differences are commonly the result of chemical changes and/or nonhomogeneities in sampled materials. The irregularities are often caused by moisture absorption during sampling, packaging, shipment, and storage of the materials. A method is proposed which eliminates the effects of chemical change in samples, particularly moisture absorption, and minimizes sampling error. A nondestructive thermal watts/gram test on every preweighed sampled and total dissolution of these samples for chemical assay are the primary features which make this method effective. Because this method minimizes the error related to exchange material, it is possible to design an interlaboratory exchange program which demonstrates the assay capabiliies of the participants. In an experiment performed to demonstrate the effectiveness of this method, three PuO/sub 2/ batches of varying isotopic composition were synthesized at Mound to be used in the exchange tess. Powder sample aliquots from each batch were weighed directly into their vials under controlled atmospheric conditions. Calorimetric heat measurements were made on each vial to test homogeneity and verify sample weight. Six vials of each batch were chemically assayed at Mound and six at NBL (New Brunswick Laboratory). Both laboratories chose controlled-potential coulometry as the chemical assay technique because of its demonstrated precision and accuracy. Total dissolution of preweighed exchange samples eliminated the need for laborious and usually futile heating to return the material to its original condition. The mean chemical assay values obtained by Mound and NBL agree to within 0.01% for each of the compositions tested. Testing of both chemical assay and calorimetric data revealed no sampling error throughout the experiment