1,797 research outputs found

    Photographic quantification of water quality in mixing zones

    Get PDF
    A method was developed to quantitatively delineate waste concentrations throughout waste effluent mixing zones on the basis of densitometric measurements extracted from aerial photography. A mixing zone is the extent of a receiving water body ultilized to dilute a waste discharge to a concentration characteristic of a totally mixed condition. Simultaneously-acquired color infrared photography and suspended solids water samples were used to quantitatively delineate the mixing zone resulting from the discharge of a paper mill effluent. Digital scanning microdensitometer data was used to estimate and delineate suspended solids concentrations on the basis of a semi-empirical model. Photographic photometry, when predicated on a limited amount of ground sampling, can measure and delineate mixing zone waste distributions in more detail then conventional surface measuring techniques. The method has direct application to: (1) the establishment of definite and rational water quality guidelines; (2) the development of sampling and surveillance programs for use by governmental and private agencies; and (3) the development of design and location criteria for industrial and municipal waste effluent outfalls

    Artificial Pruning in Coniferous Plantations

    Get PDF
    The pruning practices here outlined should be applicable on the thousands of acres of coniferous plantations which have been established in southern New England and portions of New York, New Jersey, and Pennsylvania having similar forest conditions

    Growing of White Pine on the Yale Forest near Keene, New Hampshire

    Get PDF

    Evaluation of the application of ERTS-1 data to the regional land use planning process

    Get PDF
    The author has identified the following significant results. Employing simple and economical extraction methods, ERTS can provide valuable data to the planners at the state or regional level with a frequency never before possible. Interactive computer methods of working directly with ERTS digital information show much promise for providing land use information at a more specific level, since the data format production rate of ERTS justifies improved methods of analysis

    Moment tensor inversion of perforation shots using distributed acoustic sensing

    Full text link
    Distributed acoustic sensing (DAS) fibers have enabled various geophysical applications in unconventional reservoirs. Combined with perforation shots, a DAS fiber can record valuable guided waves that propagate in the reservoir formation and carry information about its properties. However, the representation of perforation shots as seismic sources, needed to conduct quantitative analysis, remains unknown. We model such sources using a superposition of three mechanisms for which we derive the moment tensor representation. Using field DAS data recorded in the same well where the perforations are located, we establish a workflow to invert the resolvable components of the total moment tensor for 100 different perforation shots. By scrutinizing the inversion results, we conjecture that the moment tensor can indicate how effectively a perforation shot creates micro-cracks in the surrounding rock. Furthermore, our inverted moment tensors form the basis for a subsequent elastic full-waveform inversion.Comment: This work has been submitted for publication in Geophysics under the reference GEO-2023-004

    The medical student

    Full text link
    The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

    Pulmonary vasoconstrictor action of KCNQ potassium channel blockers

    Get PDF
    KCNQ channels have been widely studied in the nervous system, heart and inner ear, where they have important physiological functions. Recent reports indicate that KCNQ channels may also be expressed in portal vein where they are suggested to influence spontaneous contractile activity. The biophysical properties of K+ currents mediated by KCNQ channels resemble a current underlying the resting K+ conductance and resting potential of pulmonary artery smooth muscle cells. We therefore investigated a possible role of KCNQ channels in regulating the function of pulmonary arteries by determining the ability of the selective KCNQ channel blockers, linopirdine and XE991, to promote pulmonary vasoconstriction. Linopirdine and XE991 both contracted rat and mouse pulmonary arteries but had little effect on mesenteric arteries. In each case the maximum contraction was almost as large as the response to 50 mM K+. Linopirdine had an EC50 of around 1 μM and XE991 was almost 10-fold more potent. Neither removal of the endothelium nor exposure to phentolamine or α,β-methylene ATP, to block α1-adrenoceptors or P2X receptors, respectively, affected the contraction. Contraction was abolished in Ca2+-free solution and in the presence of 1 μM nifedipine or 10 μM levcromakalim

    Dvoretzky type theorems for multivariate polynomials and sections of convex bodies

    Full text link
    In this paper we prove the Gromov--Milman conjecture (the Dvoretzky type theorem) for homogeneous polynomials on Rn\mathbb R^n, and improve bounds on the number n(d,k)n(d,k) in the analogous conjecture for odd degrees dd (this case is known as the Birch theorem) and complex polynomials. We also consider a stronger conjecture on the homogeneous polynomial fields in the canonical bundle over real and complex Grassmannians. This conjecture is much stronger and false in general, but it is proved in the cases of d=2d=2 (for kk's of certain type), odd dd, and the complex Grassmannian (for odd and even dd and any kk). Corollaries for the John ellipsoid of projections or sections of a convex body are deduced from the case d=2d=2 of the polynomial field conjecture

    Multiple solutions to a magnetic nonlinear Choquard equation

    Full text link
    We consider the stationary nonlinear magnetic Choquard equation [(-\mathrm{i}\nabla+A(x))^{2}u+V(x)u=(\frac{1}{|x|^{\alpha}}\ast |u|^{p}) |u|^{p-2}u,\quad x\in\mathbb{R}^{N}%] where A A\ is a real valued vector potential, VV is a real valued scalar potential,, N≥3N\geq3, α∈(0,N)\alpha\in(0,N) and 2−(α/N)<p<(2N−α)/(N−2)2-(\alpha/N) <p<(2N-\alpha)/(N-2). \ We assume that both AA and VV are compatible with the action of some group GG of linear isometries of RN\mathbb{R}^{N}. We establish the existence of multiple complex valued solutions to this equation which satisfy the symmetry condition u(gx)=τ(g)u(x)   for allg∈G,x∈RN, u(gx)=\tau(g)u(x)\text{\ \ \ for all}g\in G,\text{}x\in\mathbb{R}^{N}, where τ:G→S1\tau:G\rightarrow\mathbb{S}^{1} is a given group homomorphism into the unit complex numbers.Comment: To appear on ZAM
    • …
    corecore