7,032 research outputs found
I Feel Religion Comin\u27 On
https://digitalcommons.library.umaine.edu/mmb-vp/4222/thumbnail.jp
The Economics of Spruce Budworm Outbreaks in the Lake States: An Overview
Economic effects of spruce budworm outbreaks in the Lake States were examined. The recent outbreak caused spruce and fir mortality on 420 thousand ha (I.OS million acres) of commercial forest land in the Lake States. Two models of Lake States spruce-fir markets were developed. A Static Economic Model established the nature of the Lake States spruce-fir market and a Comparative Static Model examined changes brought about by spruce budworm outbreaks.
Outbreaks result in short-run supply shifts which probably decrease total revenue to stumpage owners but do not affect demand. The magnitude of long-run impacts were dependent on developing Lake States markets and forest management techniques. Further research is necessary on the value of short-run losses to stumpage owners so that the costs of forest management can be compared with outbreak losses. Long-run shifts in demand can be facilitated by attracting new industry to the area, developing new markets for the spruce-fir resource, and demonstrating that the spruce-fir resource can provide a continuous fiber source in the future.
These shifts would provide the price incentives that land managers require to undertake intensive forest management. Research on the development of new markets for the spruce-fir resource is needed. As markets develop, the long-run impacts become less severe. Technology transfer programs already exist to aid land managers in developing management strategies to increase yields of spruce-fir and minimize outbreak impact
Aeroelastic analysis of wings using the Euler equations with a deforming mesh
Modifications to the CFL3D three dimensional unsteady Euler/Navier-Stokes code for the aeroelastic analysis of wings are described. The modifications involve including a deforming mesh capability which can move the mesh to continuously conform to the instantaneous shape of the aeroelastically deforming wing, and including the structural equations of motion for their simultaneous time-integration with the governing flow equations. Calculations were performed using the Euler equations to verify the modifications to the code and as a first step toward aeroelastic analysis using the Navier-Stokes equations. Results are presented for the NACA 0012 airfoil and a 45 deg sweptback wing to demonstrate applications of CFL3D for generalized force computations and aeroelastic analysis. Comparisons are made with published Euler results for the NACA 0012 airfoil and with experimental flutter data for the 45 deg sweptback wing to assess the accuracy of the present capability. These comparisons show good agreement and, thus, the CFL3D code may be used with confidence for aeroelastic analysis of wings
Structural aspects of molecular recognition in the immune system. Part II: Pattern recognition receptors (IUPAC Technical Report)
The vertebrate immune system uses pattern recognition receptors (PRRs) to detect a large variety of molecular signatures (pathogen-associated molecular patterns, PAMPs) from a broad range of different invading pathogens. The PAMPs range in size from relatively small molecules, to others of intermediate size such as bacterial lipopolysaccharide, lipopeptides, and oligosaccharides, to macromolecules such as viral DNA, RNA, and pathogen-derived proteins such as flagellin. Underlying this functional diversity of PRRs is a surprisingly small number of structurally distinct protein folds that include leucine-rich repeats in Toll-like receptors (TLRs) and NOD-like receptors (NLRs), the DExH box helicase domain in RIG-like receptors (RLRs), and C-type lectin domains (CTLDs) in the C-type lectins. Following PAMP recognition by the PRRs, downstream signaling pathways activate the innate immune system to respond to invading pathogenic organisms. The resulting stimulatory response is also vital for a balanced adaptive immune response to the pathogen, mediated by circulating antibodies and/or cytotoxic T cells. However, an aberrant stimulation of the innate immune system can also lead to excessive inflammatory and toxic stress responses. Exciting opportunities are now arising for the design of small synthetic molecules that bind to PRRs and influence downstream signaling pathways. Such molecules can be useful tools to modulate immune responses, for example, as adjuvants to stimulate adaptive immune responses to a vaccine, or as therapeutic agents to dampen aberrant immune responses, such as inflammation. The design of agonists or antagonists of PRRs can now benefit from a surge in knowledge of the 3D structures of PRRs, many in complexes with their natural ligands. This review article describes recent progress in structural studies of PRRs (TLRs, NLRs, CTLs, and RLRs), which is required for an understanding of how they specifically recognize structurally diverse "foreign” PAMPs amongst a background of other "self” molecules, sometimes closely related in structure, that are present in the human bod
Reflection high-energy electron diffraction patterns of CrSi_2 films on (111) silicon
Highly oriented films of the semiconducting transition metal silicide, CrSi2, were grown on (111) silicon substrates, with the matching crystallographic faces being CrSi_2(001)/Si(111). Reflection high‐energy electron diffraction (RHEED) yielded symmetric patterns of sharp streaks. The expected streak spacings for different incident RHEED beam directions were calculated from the reciprocal net of the CrSi_2(001) face and shown to match the observed spacings. The predominant azimuthal orientation of the films was thus determined to be CrSi_2〈210〉∥Si〈110〉. This highly desirable heteroepitaxial relationship may be described with a common unit mesh of 51 Å^2 and a mismatch of −0.3%. RHEED also revealed the presence of limited film regions of a competing azimuthal orientation, CrSi_2〈110〉∥Si〈110〉. A new common unit mesh for this competing orientation is suggested; it possesses an area of 612 Å^2 and a mismatch of −1.2%
Attempted DNA extraction from a Rancho La Brea Columbian mammoth (Mammuthus columbi): prospects for ancient DNA from asphalt deposits.
Fossil-bearing asphalt deposits are an understudied and potentially significant source of ancient DNA. Previous attempts to extract DNA from skeletons preserved at the Rancho La Brea tar pits in Los Angeles, California, have proven unsuccessful, but it is unclear whether this is due to a lack of endogenous DNA, or if the problem is caused by asphalt-mediated inhibition. In an attempt to test these hypotheses, a recently recovered Columbian mammoth (Mammuthus columbi) skeleton with an unusual pattern of asphalt impregnation was studied. Ultimately, none of the bone samples tested successfully amplified M. columbi DNA. Our work suggests that reagents typically used to remove asphalt from ancient samples also inhibit DNA extraction. Ultimately, we conclude that the probability of recovering ancient DNA from fossils in asphalt deposits is strongly (perhaps fatally) hindered by the organic compounds that permeate the bones and that at the Rancho La Brea tar pits, environmental conditions might not have been ideal for the general preservation of genetic material
Clearing Up Rollo May’s Views of Transpersonal Psychology and Acknowledging May as an Early Supporter of Ecopsychology
This paper explores Rollo May’s 1992 reassessment of transpersonal psychology, in which he reverses
his 1986 and 1989 arguments against transpersonal psychology. Equally relevant, this paper shows
that May was actually interested in supporting what is now called ecopsychology. Schroll (following
Alan Drengson and Arne Naess) now refers to ecopsychology as transpersonal ecosophy. This paper
offers a thorough examination of several key concerns that May had regarding his reservations
toward accepting transpersonal psychology’s legitimacy, and includes May’s vigorous discussion with
Ken Wilber. Wilber’s discussion with Kirk Schneider’s 1987 and 1989 critique of transpersonal
psychology is also examined. Likewise Albert Ellis’ 1986 and 1989 rejection and misunderstanding
of transpersonal psychology is discussed
Synthesis and antimicrobial activity against Pseudomonas aeruginosa of macrocyclic β-hairpin peptidomimetic antibiotics containing N-methylated amino acids
Antimicrobial resistance among Gram-negative bacteria is a growing problem, fueled by the paucity of new antibiotics that target these microorganisms. One novel family of macrocyclic β-hairpin-shaped peptidomimetics was recently shown to act specifically against Pseudomonas spp. by a novel mechanism of action, targeting the outer membrane protein LptD, which mediates lipopolysaccharide transport to the cell surface during outer membrane biogenesis. Here we explore the mode of binding of one of these β-hairpin peptidomimetics to LptD in Pseudomonas aeruginosa, by examining the effects on antimicrobial activity following N-methylation of individual peptide bonds. An N-methyl scan of the cyclic peptide revealed that residues on both sides of the β-hairpin structure at a non-hydrogen bonding position likely mediate hydrogen-bonding interactions with the target LptD. Structural analyses by NMR spectroscopy further reinforce the conclusion that the folded β-hairpin structure of the peptidomimetic is critical for binding to the target LptD. Finally, new NMe analogues with potent activity have been identified, which opens new avenues for optimization in this family of antimicrobial peptides
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