2,405 research outputs found
Establishment and Growth of Cherrybark Oak Seedlings Underplanted Beneath a Partial Overstory in a Minor Bottom of Southwestern Arkansas: First Year Results
-Advance regeneration is frequently inadequate to sufficiently restock the oak component of many bottomland stands, especially on productive sites with high levels of competition. We initiated a study near Beirne, AR to examine the effects of pre-plant control of Japanese honeysuckle Thunberg) and seedling quality on establishment success and vigor of oak reproduction beneath a partial canopy. Nine, 2-acre plots were delineated in the stand that was harvested a residual stocking level of 30 percent in the fall of 1996. Honeysuckle pre-plant control treatments randomly applied to the nine were an Escort application in the spring of 1997, an Escort application in the summer of 1997, and a control (no herbicide application). In 1998, 1-O cherrybark oak (Quercus pagoda Raf.) seedlings were planted at a 12 ft x 12 ft spacing in each treatment plot. One-half of each treatment plot received seedlings with four or more roots 0.04 in. diameter, while the other half of each plot received seedlings with fewer than four lateral roots 0.04 in. The spring application of Escort provided effective control against Japanese honeysuckle, thereby producing potentially promising conditions for oak seedling growth and development. First-year seedling survival and growth did not respond to honeysuckle control treatments. Survival was not related seedling quality, and first-year differences in seedling size were attributed to initial size differences in stock types
Modelling The Dipole Moment Function Of Carbon Monoxide Capable Of Predicting The Rotational Distribution In The 7-0 Band
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The rotational distributions of the intensities in the low-v vibrational bands are nearly insensitive to the specific forms of the PEFs and DMFs based on the experimental and/or \textit{ab initio} data. This is not the case for the higher overtone bands. We discuss the problem: Which properties should the model PEF and DMF possess in order to be capable of predicting the intensities of the yet unobserved lines? Arguments are presented that the Born-Oppenheimer PEF and DMF should possess some features following from their properties as functions of the inter-atomic separation as a complex variable. In particular, they must contain branch points associated with the crossings between the ground and excited electronic states. This approach implies that both functions are to be fitted simultaneously to the common data set including both the line positions and the intensities. However, such a problem is very difficult to solve. Here and in Ref. (1), in application to CO, we assume that the PEF is given (2), and we develop an irregular DMF form containing two branch points corresponding to the expected crossings in the complex plane near 0.4 and {2.2 \AA}. We compare it with an alternative regular function (1) and find that the rotational distribution in the vibrational 7-0 band predicted by the former is very stable with respect to small variations in the data base, as opposed to the regular DMF showing strong instability. The predicted intensities (see figure) are stronger than the HITRAN values calculated by Li et al. (3) with a combined empirical/spline-interpolated \textit{ab initio} DMF but are close to the ones calculated by us with the purely empirical DMF of Li et al. The irregular function is expected to provide for a reliable prediction of the ro-vibrational line intensities in the 7-0 band.
This work was performed in accordance with the state task, state registration No. AAAA-A19-119071190017-7.
(1) V. V. Meshkov, A. V. Stolyarov, A. Yu. Ermilov, E. S. Medvedev, V. G. Ushakov, I. E. Gordon, JQSRT (in preparation); (2) JQSRT 217 (2018 ) 262-273. (3) G. Li, I. E. Gordon, L. S. Rothman, Y. Tan, S.-M. Hu, S. Kassi, A. Campargue, E. S. Medvedev, Astrophys. J., Suppl. Ser. 216 (2015) 15
GELDART GROUP INDICATION FROM POWDER MEASUREMENTS WITH A ROTATING DRUM INSTRUMENT
Data have been collected with a GDR, for powders from each Geldart Group, over a rotation rates in the range 0-22 r.p.m.. Composite plots of avalanching frequency ,slumping rate and rotation rate, show that power spectral density for Groups D and B is qute different from that observed for Groups A and C
THE PHYSIOLOGICAL RESPONSE OF THE CIRCULATORY SYSTEM TO EXPERIMENTAL ALTERATIONS : II. THE EFFECT OF VARIATIONS IN TOTAL BLOOD VOLUME.
The pericardium presents a limiting or constricting action to acute dilatation of the heart. The diastolic pressure tends to approach the systolic pressure in a circulatory system distended with blood. The limiting action of the pericardium may be responsible for the small differences in the size of the heart noted by Meek and Eyster in their studies on the effect of plethora. The views concerning the function of the pericardium are divergent. That it may restrict the heart in cases of acute dilatation is shown in the above experiments. If the tension upon the pericardium be exerted over a prolonged period of time, as occurs in cases of pericardial effusion, the pericardium readily enlarges. If, however, the intrapericardial pressure should at any time equal the pressure in the venæ cavæ, blood would no longer enter the heart and the condition would become fatal. In recovery experiments, pericardiectomy was followed by no demonstrable effect upon the general health of the dog, upon the response to exercise, or upon the size of the heart (6)
Mechanism of long-range proton translocation along biological membranes
AbstractRecent experiments suggest that protons can travel along biological membranes up to tens of micrometers, but the mechanism of transport is unknown. To explain such a long-range proton translocation we describe a model that takes into account the coupled bulk diffusion that accompanies the migration of protons on the surface. We show that protons diffusing at or near the surface before equilibrating with the bulk desorb and re-adsorb at the surface thousands of times, giving rise to a power-law desorption kinetics. As a result, the decay of the surface protons occurs very slowly, allowing for establishing local gradient and local exchange, as was envisioned in the early local models of biological energy transduction
Theoretical and computational analysis of the membrane potential generated by cytochrome c oxidase upon single electron injection into the enzyme
AbstractWe have developed theory and the computational scheme for the analysis of the kinetics of the membrane potential generated by cytochrome c oxidase upon single electron injection into the enzyme. The theory allows one to connect the charge motions inside the enzyme to the membrane potential observed in the experiments by using data from the “dielectric topography” map of the enzyme that we have created. The developed theory is applied for the analysis of the potentiometric data recently reported by the Wikström group [I. Belevich, D.A. Bloch, N. Belevich, M. Wikström and M.I. Verkhovsky, Exploring the proton pump mechanism of cytochrome c oxidase in real time, Proc. Natl. Acad. Sci. U. S. A. 104 (2007) 2685–2690] on the O to E transition in Paracoccus denitrificans oxidase. Our analysis suggests, that the electron transfer to the binuclear center is coupled to a proton transfer (proton loading) to a group just “above” the binuclear center of the enzyme, from which the pumped proton is subsequently expelled by the chemical proton arriving to the binuclear center. The identity of the pump site could not be determined with certainty, but could be localized to the group of residues His326 (His291 in bovine), propionates of heme a3, Arg 473/474, and Trp164. The analysis also suggests that the dielectric distance from the P-side to Fe a is 0.4 or larger. The difficulties and pitfalls of quantitative interpretation of potentiometric data are discussed
High performance WR-1.5 corrugated horn based on stacked rings
We present the development and characterisation of a high frequency (500-750
GHz) corrugated horn based on stacked rings. A previous horn design, based on a
Winston profile, has been adapted for the purpose of this manufacturing process
without noticeable RF degradation. A subset of experimental results obtained
using a vector network analyser are presented and compared to the predicted
performance. These first results demonstrate that this technology is suitable
for most commercial applications and also astronomical receivers in need of
horn arrays at high frequencies.Comment: 9 page
The left ventricular outflow tract and carotid artery velocity time integrals
The left ventricular outflow tract velocity time integral (LVOT VTI) is commonly used in the intensive care unit as a measure of stroke volume (SV) and how the SV changes in response to an intervention; therefore, the LVOT VTI is used to guide intravenous fluid management. Various peripheral Doppler surrogates are proposed to infer the LVOT VTI (e.g., measures from the common carotid artery). A recently-described, novel method of insonation has an excellent ability to detect change in the LVOT VTI. This approach raises important facets of Doppler flow and insonation error, as well as the general principles at play when using a peripheral artery to infer changes from the left ventricle. Relating the VTI of a peripheral artery to the LVOT VTI was recently described mathematically and may help clinicians think about the Doppler relationship between central and peripheral flow
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