Standard-Level Herbivory in an Old-Growth Conifer Forest Canopy

Herbivory is an important ecological process in forest canopies but is difficult to measure, especially for whole stands. We used the Wind River Canopy Crane in Washington State to access 101 randomly-located sample points throughout the forest canopy. This provided a relatively quick and convenient way to estimate herbivory for a whole stand. The overall level of herbivory was estimated at 1.6% of leaf area. The distribution was strongly skewed to the lower canopy where broad-leafed species experienced higher levels of herbivory. Herbivory averaged 0.3% in conifers and 13.5% in broad-leafed species. Fully half of the sample points had no detectable herbivory. Herbivory in this old-growth conifer forest is among the lowest levels published for forests around the globe and may reflect the general levels of herbivory in temperate coniferous forests during nonoutbreak conditions. Our whole-stand estimate is the first attempt at measuring herbivory for an entire forest stand in the Pacific Northwest

Shaped nozzles for cryogenic buffer gas beam sources

Cryogenic buffer gas beams are important sources of cold molecules. In this work we explore the use of a converging-diverging nozzle with a buffer-gas beam. We find that, under appropriate circumstances, the use of a nozzle can produce a beam with improved collimation, lower transverse temperatures, and higher fluxes per solid angle

Streaming Motions Towards the Supermassive Black Hole in NGC 1097

We have used GMOS-IFU and high resolution HST-ACS observations to map, in unprecedented detail, the gas velocity field and structure within the 0.7 kpc circumnuclear ring of the SBb LINER/Seyfert 1 galaxy NGC 1097. We find clear evidence of radial streaming motions associated with spiral structures leading to the unresolved (<3.5 parsecs) nucleus, which we interpret as part of the fueling chain by which gas is transported to the nuclear starburst and supermassive black hole.Comment: 4 pages, 3 figures using emulateapj. Accepted for publication in Astrophysical Journal Letters. Download high-resolution version from http://www.astro.uu.se/~kambiz/DOC/paper-N1097.pd

Field guide to the forested plant associations of the Mt. Baker-Snoqualmie National Forest

A classification of forest vegetation is presented for the Mt. Baker-snoqualmie Forest. It is based on the potential National vegetation and uses the plant association as the basic unit. The classification is based on 2464 sample plots distributed across the Forest from 1979 to 1990. Of these 1963 were in late successional stands over 150 years old. An additional 633 plots were taken in non-forest communities or undescribed plant associations. The hierarchical classification includes 4 forest series, 19 plant association groups, and 60 plant associations. Diagnostic keys are presented to aid in the identification of vegetation series and plant associations. Descriptions are presented for each series and association. Plant association descriptions include information about plant species occurrences, distribution, environment and soils, potential timber productivity, management considerations, and comparisons with similar plant associations. Key words: vegetation classification, climax plant communities, potential vegetation, plant association, vegetation series, forest ecology, forest environment, Cascade Mountains

Forested plant associations of the Olympic National Forest

A potential vegetation classification system is presented for the Olympic National Forest. It is based on a sample of 1046 Reconnaissance and 408 Intensive plots. The hierarchical classification includes sixvegetation series and 64 plant associations. Diagnostickeys are presented to aid in the identification of series and associations. Descriptions are presented for each series and association which are oriented toward the application of this classification for land management objectives. Association descriptions include information about plant species occurrences, including mosses and lichens, mammals, birds, insect pests and diseases. Most descriptions include information on timber productivity and soils. Background information is also presented on the ecology, geology, soils and history of the Olympic Mountains. Key words: vegetation classification, climax vegetation, climax plant communities, plant association, vegetation series, plant community ecology, forest ecology, mosses, lichens, birds, mammals, forest diseases, timber productivity, soil, Olympic Mountains

Studies of inactivation mechanism of non-enveloped icosahedral virus by a visible ultrashort pulsed laser

BACKGROUND: Low-power ultrashort pulsed (USP) lasers operating at wavelengths of 425 nm and near infrared region have been shown to effectively inactivate viruses such as human immunodeficiency virus (HIV), M13 bacteriophage, and murine cytomegalovirus (MCMV). It was shown previously that non-enveloped, helical viruses such as M13 bacteriophage, were inactivated by a USP laser through an impulsive stimulated Raman scattering (ISRS) process. Recently, enveloped virus like MCMV has been shown to be inactivated by a USP laser via protein aggregation induced by an ISRS process. However, the inactivation mechanism for a clinically important class of viruses – non-enveloped, icosahedral viruses remains unknown. RESULTS AND DISCUSSIONS: We have ruled out the following four possible inactivation mechanisms for non-enveloped, icosahedral viruses, namely, (1) inactivation due to ultraviolet C (UVC) photons produced by non-linear optical process of the intense, fundamental laser beam at 425 nm; (2) inactivation caused by thermal heating generated by the direct laser absorption/heating of the virion; (3) inactivation resulting from a one-photon absorption process via chromophores such as porphyrin molecules, or indicator dyes, potentially producing reactive oxygen or other species; (4) inactivation by the USP lasers in which the extremely intense laser pulse produces shock wave-like vibrations upon impact with the viral particle. We present data which support that the inactivation mechanism for non-enveloped, icosahedral viruses is the impulsive stimulated Raman scattering process. Real-time PCR experiments show that, within the amplicon size of 273 bp tested, there is no damage on the genome of MNV-1 caused by the USP laser irradiation. CONCLUSION: We conclude that our model non-enveloped virus, MNV-1, is inactivated by the ISRS process. These studies provide fundamental knowledge on photon-virus interactions on femtosecond time scales. From the analysis of the transmission electron microscope (TEM) images of viral particles before and after USP laser irradiation, the locations of weak structural links on the capsid of MNV-1 were revealed. This important information will greatly aid our understanding of the structure of non-enveloped, icosahedral viruses. We envision that this non-invasive, efficient viral eradication method will find applications in the disinfection of pharmaceuticals, biologicals and blood products in the near future

A Chandra X-ray Study of Cygnus A - II. The Nucleus

We report Chandra ACIS and quasi-simultaneous RXTE observations of the nearby, powerful radio galaxy Cygnus A, with the present paper focusing on the properties of the active nucleus. In the Chandra observation, the hard (> a few keV) X-ray emission is spatially unresolved with a size \approxlt 1 arcsec (1.5 kpc, H_0 = 50 km s^-1 Mpc^-1) and coincides with the radio and near infrared nuclei. In contrast, the soft (< 2 keV) emission exhibits a bi-polar nebulosity that aligns with the optical bi-polar continuum and emission-line structures and approximately with the radio jet. In particular, the soft X-ray emission corresponds very well with the [O III] \lambda 5007 and H\alpha + [N II] \lambda\lambda 6548, 6583 nebulosity imaged with HST. At the location of the nucleus there is only weak soft X-ray emission, an effect that may be intrinsic or result from a dust lane that crosses the nucleus perpendicular to the source axis. The spectra of the various X-ray components have been obtained by simultaneous fits to the 6 detectors. The compact nucleus is detected to 100 keV and is well described by a heavily absorbed power law spectrum with \Gamma_h = 1.52^{+0.12}_{-0.12} (similar to other narrow line radio galaxies) and equivalent hydrogen column N_H (nuc) = 2.0^{+0.1}_{-0.2} \times 10^{23} cm^-2. (Abstract truncated).Comment: To be published in the Astrophysical Journal, v564 January 1, 2002 issue; 34 pages, 11 figures (1 color

Electrostatic guiding of the methylidyne radical at cryogenic temperatures

We have produced a cryogenic buffer-gas cooled beam of the diatomic molecular radical CH (methylidyne). This molecule is of interest for studying cold chemical reactions and fundamental physics measurements. Its light mass and ground-state structure make it a promising candidate for electrostatic guiding and Stark deceleration, which allows for control over its kinetic energy. This control can facilitate studies of reactions with tuneable collision energies and trapping for precise spectroscopic studies. Here, we have demonstrated electrostatic guiding of CH with fluxes up to $10^9$ molecules per steradian per pulseComment: 10 pages, 10 figure

Pathogen reduction in human plasma using an ultrashort pulsed laser

Pathogen reduction is a viable approach to ensure the continued safety of the blood supply against emerging pathogens. However, the currently licensed pathogen reduction techniques are ineffective against non-enveloped viruses such as hepatitis A virus, and they introduce chemicals with concerns of side effects which prevent their widespread use. In this report, we demonstrate the inactivation of both enveloped and non-enveloped viruses in human plasma using a novel chemical-free method, a visible ultrashort pulsed laser. We found that laser treatment resulted in 2-log, 1-log, and 3-log reductions in human immunodeficiency virus, hepatitis A virus, and murine cytomegalovirus in human plasma, respectively. Laser-treated plasma showed ≥70% retention for most coagulation factors tested. Furthermore, laser treatment did not alter the structure of a model coagulation factor, fibrinogen. Ultrashort pulsed lasers are a promising new method for chemical-free, broad-spectrum pathogen reduction in human plasma