46,649 research outputs found
Letter from A. F. Potter to John H. Page
No full textLetter from A. F. Potter to John H. Page referring his request to build a railway to the District Forester at Albuquerque, New Mexico
Polly H. Carder Collection on George F. Root
No full textGeorge Frederick Root (1820-1895) was an American songwriter and music educator. He is perhaps best known for his song "The Battle Cry of Freedom," which was written and rose to popularity during the U.S. Civil War. The Polly H. Carder Collection on George F. Root contains original published scores and songbooks from the period 1852-1907 and photocopied scores collected by Polly H. Carder, author of the book George F. Root, Civil War Songwriter: A Biography. The collection also contains a short article, "The Last Days of George F. Root," written by Root's daughter, Clara Louise Burnham
Parallelogram Excision: An Algorithmic Approach for Excision Designs in High-Tension Skin Areas
No full textIntroduction: The excision of lesions that are not oriented along the skin tension lines may cause the surgeon to design extremely broad elliptical preoperative markings, with the intent to follow the tension lines as recommended for the best postoperative course and the best quality scars. The aim of this study is to describe and clinically apply a new surgical technique called the parallelogram excision technique, in which the traditional ellipse with a major axis parallel to the tension lines is converted into a parallelogram whose lesser sides are coincident with the local skin tension lines. This technique was specifically conceived for lesions whose major axis is non-coincident with skin tension lines, and the primary advantage is that it reduces the amount of healthy tissue excised. Methods: Preliminarily to this clinical study, a comparative geometrical analysis was conducted between various excision shapes and angles using Geometry Pad version 2.7.10 (Bytes Arithmetic LLC) and verifying the data obtained through AutoCAD 2D 2016 (Autodesk, San Rafael, CA, USA), with the purpose of optimizing the technique from a geometrical point of view. A comparison was performed between the theoretical traditional elliptical excision and the hypothetical parallelogram excision. A pilot proof of concept clinical study was performed to verify the validity of the excisional design proposed. The patients considered for parallelogram excision suffered from skin lesions with a diameter no greater than 4 cm and oriented 45 degrees to 60 degrees with respect to tension lines. In order to limit variability, patients' ages were between 40 and 80, and the selected areas were limbs, sternum and dorsum. Scar quality was assessed with the validated POSAS method at 6 months post-operation. Results: The geometrical analysis of the parallelogram's design showed that it allows a diminution of the excised healthy skin compared to the traditional ellipse. The clinical series included 16 patients, with a mean age of 63.5. Of these, nine patients were men and seven were women. Diagnoses included basal cell carcinoma in seven cases, dysplastic naevus in five patients, Bowen's disease in three individuals, and one case where a wider excision of a malignant melanoma was performed. Six-month follow up results showed: (1) an uneventful postoperative course; (2) good scar healing with an observer's POSAS median score of 16 and a patient's POSAS median score of 19; and (3) complete excision of lesions. Conclusions: When indicated, the parallelogram excision technique appears to be a good option for the excision and primary closure of skin lesions that are not parallel to skin tension lines, since it allows a reproducible and surgeon-friendly method of preoperative marking and implies a favorable use of the local tension, which determines good quality scars. The amount of healthy tissue removed is smaller compared to traditional elliptic excisions
Algebraic Representation of Social Capital Matrix
Get PDFThis paper proposes a mathematical model based on a Boolean algebra involving a 44 social capital matrix [Shah (2008)], that emerges through interaction within and across individuals, communities, institutions and state. The framework provides a coding system for the existence or otherwise of various categories of social interaction. The model illustrates that social interaction can be neatly described in a format that facilitates the interpretation of social intra- and interactions among the four types of players in generating economic activity.Social Capital (Matrix), Linear Space, Interactive Systems, Boolean Algebra
Algebraic Representation of Social Capital Matrix
Get PDFThis paper proposes a mathematical model based on a Boolean algebra involving a 4×4 social capital matrix [Shah (2008)], that emerges through interaction within and across individuals, communities, institutions and state. The framework provides a coding system for the existence or otherwise of various categories of social interaction. The model illustrates that social interaction can be neatly described in a format that facilitates the interpretation of social intra- and interactions among the four types of players in generating economic activity.Social Capital (Matrix), Linear Space, Interactive Systems, Boolean Algebra
A fiscal needs approach to equalization transfers in a decentralized federation
Get PDFThe author reviews the conceptual basis for fiscal equalization transfers, analyzes the theoretical implications for optimal design of equalization transfers, and suggests quantitative approaches for assessing the fiscal needs of subnational governments and determining their entitlement to transfers. The author illustrates proposed methods using data for local and provincial Canadian governments. The proposed methods could be useful tools, he says, for undertaking systematic objective reviews of aggregate and sectoral public spending in developing countries. The author argues that in a decentralized federation, fiscal inefficiencies and inequities arise because of subnational governments'differing levels of ability to provide comparable public services at comparable tax rates. Fiscal equalization transfers that reduce or eliminate differentials in net fiscal benefits create a rare instance in economics when considerations of equity and efficiency coincide. These transfers must allow for differences in the spending needs and revenues-raising abilities of the various subnational governments. The author argues for a two-tiered approach to equalization. The first tier would be a federal responsibility to equalize the burden of federal taxes. The second tier would be an interprovincial equalization fund to be administered by the Council of Provincial Finance Ministers. It would entail a comprehensive equalization system that takes into account provincial spending needs. The standard of equalization would be negotiated.Public Sector Economics&Finance,Banks&Banking Reform,Municipal Financial Management,National Governance,Environmental Economics&Policies
Development of the all-vanadium redox flow battery for energy storage: a review of technological, financial and policy aspects
Get PDFThe commercial development and current economic incentives associated with energy storage using redox flow batteries (RFBs) are summarised. The analysis is focused on the all-vanadium system, which is the most studied and widely commercialised RFB. The recent expiry of key patents relating to the electrochemistry of this battery has contributed to significant levels of commercialisation in, for example, Austria, China and Thailand, as well as pilot-scale developments in many countries. The potential benefits of increasing battery-based energy storage for electricity grid load levelling and MW-scale wind/solar photovoltaic-based power generation are now being realised at an increasing level. Commercial systems are being applied to distributed systems utilising kW-scale renewable energy flows. Factors limiting the uptake of all-vanadium (and other) redox flow batteries include a comparatively high overall internal costs of 0.10?kW?1?h?1. There is also a low-level utility scale acceptance of energy storage solutions and a general lack of battery-specific policy-led incentives, even though the environmental impact of RFBs coupled to renewable energy sources is favourable, especially in comparison to natural gas- and diesel-fuelled spinning reserves. Together with the technological and policy aspects associated with flow batteries, recent attempts to model redox flow batteries are considered. The issues that have been addressed using modelling together with the current and future requirements of modelling are outlined
A second order minimality condition for the Mumford-Shah functional
No full textA new necessary minimality condition for the Mumford-Shah functional is derived by means of second order variations. It is expressed in terms of a sign condition for a nonlocal quadratic form on H^1_0(\Gamma), \Gamma being a submanifold of the regular part of the discontinuity set of the critical point. Two equivalent formulations are provided: one in terms of the first eigenvalue of a suitable compact operator, the other involving a sort of nonlocal capacity of \Gamma. A sufficient condition for minimality is also deduced. Finally, an explicit example is discussed, where a complete characterization of the domains where the second variation is nonnegative can be given
Electron and positron scattering from 1,1-C₂H₂F₂
Get PDF1,1-difluoroethylene (1,1-C₂H₂F₂) molecules have been studied for the first time experimentally and theoretically by electron and positron impact. 0.4-1000 eV electron and 0.2-1000 eV positron impact total cross sections (TCSs) were measured using a retarding potential time-of-flight apparatus. In order to probe the resonances observed in the electron TCSs, a crossed-beam method was used to investigate vibrational excitation cross sections over the energy range of 1.3-49 eV and scattering angles 90 degrees and 120 degrees for the two loss energies 0.115 and 0.381 eV corresponding to the dominant C-H (ν₂ and ν₉) stretching and the combined C-F (ν₃) stretching and CH₂ (ν₁₁) rocking vibrations, respectively. Electron impact elastic integral cross sections are also reported for calculations carried out using the Schwinger multichannel method with pseudopotentials for the energy range from 0.5 to 50 eV in the static-exchange approximation and from 0.5 to 20 eV in the static-exchange plus polarization approximation. Resonance peaks observed centered at about 2.3, 6.5, and 16 eV in the TCSs have been shown to be mainly due to the vibrational and elastic channels, and assigned to the B₂, B₁, and A₁ symmetries, respectively. The pi* resonance peak at 1.8 eV in C₂H₄ is observed shifted to 2.3 eV in 1,1-C₂H₂F₂ and to 2.5 eV in C₂F₄; a phenomenon attributed to the decreasing C=C bond length from C₂H₄ to C₂F₄. For positron impact a conspicuous peak is observed below the positronium formation threshold at about 1 eV, and other less pronounced ones centered at about 5 and 20 eV.The work was supported in part by a Grant-in-Aid, the
Ministry of Education, Science, Technology, Sport and Culture,
Japan, the Japan Society for the Promotion of Science
JSPS, and the Japan Atomic Energy Research Institute
JAERI. One of the authors C.M. is also grateful to the
JSPS for financial support under Grant No. P04064. Another
author H.T. acknowledges Dr. T. Ozeki of the JAERI for
his encouragement and support during this work. This work
was also done under the International Atomic Energy Agency
IAEA project for three of the authors C.M., M.H., and
H.T.. Two of the authors M.H.F.B. and M.A.P.L. acknowledge
support from the Brazilian agency Conselho Nacional
de Desenvolvimento Científico e Tecnológico CNPq.
MHFB also acknowledges support from the Paraná state
agency Fundação Araucária and from FINEP ( under Project
No. CT-Infra 1)
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