Birds of the Oak Lake Field Station

A preliminary check-off list of avian species was compiled using regional field guides shortly after the establishment of the field station (Northern Plains Biological Field Station Committee 1987). While this list has been a useful reference, little observational data have been available to establish accuracy. Field observation data were collected to verify this checklist and establish a baseline inventory of resident and migratory avifauna for the station. Obse1vations were collected Janua1y 1994 through August 1996 during bird watching expeditions and research activities. In addition, formal bird counts were conducted at eight sites along 100 m transects of 30 m fixed width from 16 May to 23 June 23 1995. Birds were tallied, based upon sight and call, along each transect on twelve dates

Patterns in Avian Community Structure and Non-Point Source Disturbance Potential Along the Land-Water Interface of a Prairie Pothole Lake

This study was conducted to test the hypothesis that bird community structure varies significantly between areas which are prone versus not prone to disturbance within the land-water interface of a prairie lake. On-site assessment of land cover and a Geographic Information System (GIS) with coverages of slope, soil erodability, soil hydrologic group and drainages were used to delineate sites prone and not prone to non-point source disturbance. Habitat and community attributes were examined within these site classes during the summer of 1995. While habitat differences between classes (prone and not prone) were inconclusive, results of avian community analyses indicated that sites prone to disturbance had significantly higher average densities (69 individuals/ha vs. 56), species richness (10.9 vs. 8.1 species) and diversity (H’=2.05 vs. 1.72) than sites not prone to disturbance. These results are consistent with observations of other ecological communities exposed to intermediate levels of disturbance. Furthermore, these results suggest a relationship between GIS generated nonpoint source disturbance potential and ecological communities within the landwater interface

Infrared High-Resolution Spectroscopy of Post-AGB Circumstellar Disks. I. HR 4049 - The Winnowing Flow Observed?

High-resolution infrared spectroscopy in the 2.3-4.6 micron region is reported for the peculiar A supergiant, single-lined spectroscopic binary HR 4049. Lines from the CO fundamental and first overtone, OH fundamental, and several H2O vibration-rotation transitions have been observed in the near-infrared spectrum. The spectrum of HR 4049 appears principally in emission through the 3 and 4.6 micron region and in absorption in the 2 micron region. The 4.6 micron spectrum shows a rich 'forest' of emission lines. All the spectral lines observed in the 2.3-4.6 micron spectrum are shown to be circumbinary in origin. The presence of OH and H2O lines confirm the oxygen-rich nature of the circumbinary gas which is in contrast to the previously detected carbon-rich material. The emission and absorption line profiles show that the circumbinary gas is located in a thin, rotating layer near the dust disk. The properties of the dust and gas circumbinary disk and the spectroscopic orbit yield masses for the individual stars, M_AI~0.58 Msolar and M_MV~0.34 Msolar. Gas in the disk also has an outward flow with a velocity of $\gtrsim$ 1 km/s. The severe depletion of refractory elements but near-solar abundances of volatile elements observed in HR 4049 results from abundance winnowing. The separation of the volatiles from the grains in the disk and the subsequent accretion by the star are discussed. Contrary to prior reports, the HR 4049 carbon and oxygen isotopic abundances are typical AGB values: 12C/13C=6^{+9}_{-4} and 16O/17O>200.Comment: 42 pages, 14 figures, Accepted by Ap

Wetenschapswinkel Wageningen UR : 25 jaar! : jubileummagazine 25 jaar Wetenschapswinkel Wageningen University & Research Centre

Dertig jaar geleden hielden studenten vier weken lang het hoofdgebouw van de Landbouwhogeschool bezet. Ze wilden niet alleen onderzoek doen voor bedrijven. En niet alleen onderzoek om het onderzoek. Ze wilden probleemgericht onderwijs en onderzoek. De universiteit moest er ook zijn voor die groepen in de samenleving die geen toegang hadden tot de zegeningen van het wetenschappelijk onderzoek. Een groepje studenten en medewerkers van de hogeschool stak tijdens die bezetting de koppen bij elkaar om de voorloper van de Wetenschapswinkel in Wageningen op te richten. De Wetenschapswinkel wilde geen rapportjes opleveren die onderin de la zouden verdwijnen. We besteedden daarom veel tijd aan het vertalen van de vraag waar de ‘klant’ mee binnenkwam naar een onderzoeksvraag die de vragensteller werkelijk verder zou brengen. Nu 25 jaar later. Kennis is voor iedereen, via internet, vrij beschikbaar

Abelian Monopoles in SU(2) Lattice Gauge Theory as Physical Objects

By numerical calculations we show that the abelian monopole currents are locally correlated with the density of SU(2) lattice action. The correlations are larger by the order of magnitude in the maximal abelian projection than in the projections which correspond to the diagonalization of Polyakov line and to the diagonalization of the plaquette. These facts show that (at least) in the maximal abelian projection the monopoles are the physical objects, they carry the SU(2) action. The larger value of \beta, the larger the relative action carried by monopole. Calculations on the asymmetric lattice show that this correlation exists also in the deconfinement phase of gluodynamics.Comment: 6 pages, RevTeX, 3 figures, uses epsf.sty; to be published in Phys.Rev.Lett., replaced to match version accepted for publicatio

Optical spectrum of the post-AGB star HD56126 in the region 4010-8790 AA

We studied in detail the optical spectrum of the post-AGB star HD56126 (IRAS07134+1005). We use high resolution spectra (R=25000 and 60000) obtained with the echelle spectrographs of the 6-m telescope. About one and a half thousand absorptions of neutral atoms and ions, absorption bands of C_2, CN, and CH molecules, and interstellar bands (DIBs) are identified in the 4010 to 8790 AA wavelength region, and the depths and radial velocities of these spectral features are measured. Differences are revealed between the variations of the radial velocities measured from spectral features of different excitation. In addition to the well-known variability of the Halpha profile, we found variations in the profiles of a number of FeII, YII, and BaII lines. We also produce an atlas of the spectrum of HD56126 and its comparison staralpha Per. The full version of the atlas is available in electronic form from Web-address: http://www.sao.ru/hq/ssl/Atlas/Atlas.htmlComment: 42 pages, 6 figure

SolRgene: an online database to explore disease resistance genes in tuber-bearing Solanum species

Background The cultivated potato (Solanum tuberosum L.) is an important food crop, but highly susceptible to many pathogens. The major threat to potato production is the Irish famine pathogen Phytophthora infestans, which causes the devastating late blight disease. Potato breeding makes use of germplasm from wild relatives (wild germplasm) to introduce resistances into cultivated potato. The Solanum section Petota comprises tuber-bearing species that are potential donors of new disease resistance genes. The aim of this study was to explore Solanum section Petota for resistance genes and generate a widely accessible resource that is useful for studying and implementing disease resistance in potato. Description The SolRgene database contains data on resistance to P. infestans and presence of R genes and R gene homologues in Solanum section Petota. We have explored Solanum section Petota for resistance to late blight in high throughput disease tests under various laboratory conditions and in field trials. From resistant wild germplasm, segregating populations were generated and assessed for the presence of resistance genes. All these data have been entered into the SolRgene database. To facilitate genetic and resistance gene evolution studies, phylogenetic data of the entire SolRgene collection are included, as well as a tool for generating phylogenetic trees of selected groups of germplasm. Data from resistance gene allele-mining studies are incorporated, which enables detection of R gene homologs in related germplasm. Using these resources, various resistance genes have been detected and some of these have been cloned, whereas others are in the cloning pipeline. All this information is stored in the online SolRgene database, which allows users to query resistance data, sequences, passport data of the accessions, and phylogenic classifications. Conclusion Solanum section Petota forms the basis of the SolRgene database, which contains a collection of resistance data of an unprecedented size and precision. Complemented with R gene sequence data and phylogenetic tools, SolRgene can be considered the primary resource for information on R genes from potato and wild tuber-bearing relatives

Emergence of a 4D World from Causal Quantum Gravity

Causal Dynamical Triangulations in four dimensions provide a background-independent definition of the sum over geometries in nonperturbative quantum gravity, with a positive cosmological constant. We present evidence that a macroscopic four-dimensional world emerges from this theory dynamically.Comment: 11 pages, 3 figures; some short clarifying comments added; final version to appear in Phys. Rev. Let