Added-mass force on elliptic airfoils

2021 ◽  
Vol 926 ◽  
Author(s):  
Eric J. Limacher
Keyword(s):  
Cross Sections ◽  
Added Mass ◽  
Mass Force ◽  
Widespread Application ◽  
Force Magnitude ◽  
Small Pitch ◽  
History Of ◽  
The Difference ◽  
Three Degree Of Freedom ◽  
Special Case

Herein, exact algebraic expressions for the non-circulatory (added-mass) forces on elliptic airfoils are derived for any two-dimensional motion – including simultaneous rectilinear acceleration and rotation – embedded in a steady free-stream flow. Despite the lengthy history of the added-mass concept and its widespread application to cylinders of various cross-sections, such closed-form expressions for elliptic cylinders, in terms of kinematic and geometric parameters alone, have remained absent from the literature until now. Inspection of the derived equations reveals that for pure pitching about a point on the chord-line, increasing thickness always decreases the added-mass force magnitude. For any given motion of the chord-line, the difference in force between thick and thin airfoils is proportional to the square of the thickness, although this difference may be positive or negative for the general three-degree-of-freedom case. In the special case of zero thickness and small pitch angles, Theodorsen's added-mass lift force on rigid thin airfoils is recovered; for large pitch angles, an exact generalization of Theodorsen's expression, applicable to the chord-normal direction, is given.

The propagation and identification of ARMA demand under simple exponential smoothing: forecasting expertise and information sharing

2020 ◽  
Vol 31 (3) ◽  
pp. 307-344
Author(s):  
Meng-Chen Hsieh ◽  
Avi Giloni ◽  
Clifford Hurvich
Keyword(s):  
Forecast Error ◽  
Moving Average ◽  
Arma Model ◽  
Exponential Smoothing ◽  
Autoregressive Moving Average ◽  
Demand Shocks ◽  
History Of ◽  
Simple Exponential Smoothing ◽  
The Difference ◽  
Special Case

Abstract It is common for firms to forecast stationary demand using simple exponential smoothing (SES) due to the ease of computation and understanding of the methodology. We consider a retailer who observes autoregressive moving average (ARMA) demand but for the sake of convenience, uses the widely available SES method to forecast its demand. This creates a potential disconnect between the true mechanism generating demand and the forecasting methodology. We show that the supplier, given a sufficiently long history of the retailer’s orders, is always able to recover the retailer’s true shocks, and in addition is able to infer the true ARMA model generating the retailer’s demand process if the retailer shares its exponential smoothing parameter. We further prove that under these assumptions, the supplier is then able to infer the retailer’s demand as well. Thus, the supplier is in possession of expertise that would benefit the retailer. However, as a result of the supplier sharing its forecasting expertise, we demonstrate that the demand the supplier will face can have a smaller or larger mean squared forecast error than when the retailer uses the suboptimal SES forecast. In addition, we show that if the supplier provides its forecasting expertise to the retailer, there may be value in the retailer sharing its demand with the supplier. We also perform a simulation study for a special case of an AR(1) demand process and demonstrate that as the sample size of data increases, the difference of mean squared errors between the supplier’s estimations of the retailer’s demand shocks and the retailer’s true demand shocks converges to zero.

Harsdörffers Geschirr

2019 ◽  
Vol 10 (1) ◽  
pp. 23-37
Author(s):  
Natalie Binczek
Keyword(s):  
Design History ◽  
History Of ◽  
The Difference

Der deutsche Barockdichter Georg Philipp Harsdörffer skizziert eine Theorie der Emblematik, die vor allem dessen Anwendungsvielfalt hervorhebt. Er hebt dabei besonders den Unterschied zwischen buchinterner und buchexterner Verwendung auf, indem er sich nicht nur für die Aufnahme der Embleme in Büchern, sondern auch auf Geschirr und Tapeten ausspricht. Der Beitrag liest Harsdörffers extensive Überlegungen nicht nur als Beiträge zur Theorie und Geschichte der Embleme als ›Sinn-Bilder‹, sondern auch als Beitrag zur Designgeschichte. German Baroque poet Georg Philipp Harsdörffer delineates a theory of emblematics that clearly sets itself apart from other contemporary theories, especially by its versatility. In particular, the author negates the difference between internal and external usage of emblems in books not only by promoting the incorporation of emblems into printed works but also by supporting their depiction on dishes and tapestries. This article strives to read Harsdörffer’s extensive thoughts on the matter of emblems not simply as another work on the theory and history of emblematics but rather as a contribution to design history as well

Immunotheraphy in Allergic Diseases

2018 ◽  
Vol 24 (11) ◽  
pp. 1174-1194
Author(s):  
Albert Roger ◽  
Maria Basagana ◽  
Aina Teniente-Serra ◽  
Nathalie Depreux ◽  
Yanina Jurgens ◽  
...  
Keyword(s):  
Specific Immunotherapy ◽  
Allergic Diseases ◽  
Specific Ige ◽  
World Population ◽  
Allergen Specific Immunotherapy ◽  
Routes Of Administration ◽  
Disease Modifying Therapy ◽  
History Of ◽  
Ige Mediated ◽  
Special Case

The prevalence of allergic diseases is increasing worldwide. It is estimated that more than 30% of the world population is now affected by one or more allergic conditions and a high proportion of this increase is in young people. The diagnosis of allergy is dependent on a history of symptoms on exposure to an allergen together with the detection of allergen-specific IgE. Accurate diagnosis of allergies opens up therapeutic options. Allergen specific immunotherapy is the only successful disease-modifying therapy for IgE-mediated allergic diseases. New therapeutic strategies have been developed or are currently under clinical trials. Besides new routes of administration, new types of allergens are being developed. The use of adjuvants may amplify the immune response towards tolerance to the antigens. In this review, we analyze different antigen-specific immunotherapies according to administration route, type of antigens and adjuvants, and we address the special case of food allergy.

Introduction

2017 ◽  
Author(s):  
Simon Kirchin
Keyword(s):  
Hilary Putnam ◽  
Bernard Williams ◽  
General Methodology ◽  
Thick Concepts ◽  
History Of ◽  
Philippa Foot ◽  
The Difference

This chapter introduces the distinction between thin and thick concepts and then performs a number of functions. First, two major accounts of thick concepts—separationism and nonseparationism—are introduced and, in doing so, a novel account of evaluation is indicated. Second, each chapter is outlined as is the general methodology, followed, third, by a brief history of the discussion of thick concepts, referencing Philippa Foot, Hilary Putnam, Gilbert Ryle, and Bernard Williams among others. Fourth, a number of relevant contrasts are introduced, such as the fact–value distinction and the difference between concepts, properties, and terms. Lastly, some interesting and relevant questions are raised that, unfortunately, have to be left aside.

The Early History of Financial Economics, 1478–1776. By Geoffrey Poitras. Cheltenham and Northampton: Edward Elgar, 2000. Pp. x, 522.

2002 ◽  
Vol 62 (1) ◽  
pp. 268-269
Author(s):  
Larry Neal
Keyword(s):  
Economic History ◽  
Financial Analysis ◽  
Adam Smith ◽  
Economic Thought ◽  
Financial History ◽  
X 522 ◽  
History Of ◽  
The Difference ◽  
Wealth Of Nations ◽  
Simon Fraser University

Economic historians usually have to explain to their economist colleagues the difference between economic history, which focuses on facts, and history of economic thought, which focuses on ideas. Our colleagues in finance departments, typically fascinated by episodes in financial history treated by economic historians, are bound to be disappointed in the lack of attention given to the development of ideas in finance by historians of economic thought. Geoffrey Poitras, a professor of finance at Simon Fraser University, makes a valiant effort to remedy these oversights in his collection of vignettes that highlight the sophistication of financial instruments and analysts of financial markets well before the time of Adam Smith. Starting in 1478 with the publication of the Treviso Arithmetic, a typical textbook of commercial arithmetic for Italian merchants, and ending with brief snippets from the Wealth of Nations, Poitras treats the reader to a fascinating potpourri of excerpts from various manuals, brief biographies of pioneers in financial analysis, and historical discursions on foreign-exchange and stock markets.

scholarly journals Reproducibility and Instruction Following in the Shop Floor Laboratory Work: The Case of a TMS Experiment

2021 ◽  
pp. 016224392110323
Author(s):  
Kristina Popova
Keyword(s):  
Measurement Procedure ◽  
Shop Floor ◽  
Experimental Uncertainty ◽  
Local Measurement ◽  
Replication Crisis ◽  
History Of ◽  
Per Se ◽  
The Difference ◽  
Methodological Guidelines ◽  
Local Procedure

The article addresses the production of reproducibility as a topic that has become acutely relevant in the recent discussions on the replication crisis in science. It brings the ethnomethodological stance on reproducibility into the discussions, claiming that reproducibility is necessarily produced locally, on the shop floor, with methodological guidelines serving as references to already established practices rather than their origins. The article refers to this argument empirically, analyzing how a group of novice neuroscientists performs a series of measurements in a transcranial magnetic stimulation experiment. Based on ethnography and video analysis, the article traces a history of the local measurement procedure invented by the researchers in order to overcome the experimental uncertainty. The article aims to demonstrate (1) how reproducibility of the local procedure is achieved in the shop floor work of the practitioners and (2) how the procedure becomes normalized and questioned as incorrect in the course of experimental practice. It concludes that the difference between guidelines and practical actions is not problematic per se; what may be problematic is that researchers can be engaged in different working projects described by the same instruction.

Streptococcus pluranimalium meningoencephalitis in a horse

2021 ◽  
pp. 104063872110234
Author(s):  
Dah-Jiun Fu ◽  
Akhilesh Ramachandran ◽  
Craig Miller
Keyword(s):  
Ribosomal Rna ◽  
Cross Sections ◽  
Nucleotide Sequencing ◽  
Formalin Fixed Paraffin ◽  
Quarter Horse ◽  
Formalin Fixed Paraffin Embedded ◽  
History Of ◽  
The Brain ◽  
Gram Positive Cocci ◽  
Formalin Fixed

A 3-y-old, female Quarter Horse with a history of acute neurologic signs was found dead and was submitted for postmortem examination. Areas of petechial and ecchymotic hemorrhage were present on cross-sections of the cerebrum, cerebellum, and brainstem. Histologic examination of the brain revealed severe, purulent meningoencephalitis and vasculitis with a myriad of intralesional gram-positive cocci. Streptococcus pluranimalium was identified from formalin-fixed, paraffin-embedded tissue obtained from sites with active lesions by PCR and nucleotide sequencing of bacterial 16S ribosomal RNA. S. pluranimalium should be considered as a cause of meningoencephalitis in a horse.

Incidence of postural headache after lumbar puncture requiring epidural blood patch: Effects of needle caliber; 2-year experience

2021 ◽  
pp. 197140092110006
Author(s):  
Warren Chang ◽  
Ajla Kadribegic ◽  
Kate Denham ◽  
Matthew Kulzer ◽  
Tyson Tragon ◽  
...  
Keyword(s):  
Risk Factors ◽  
Lumbar Puncture ◽  
Conservative Management ◽  
Epidural Blood Patch ◽  
Female Gender ◽  
Regional Hospital ◽  
Younger Age ◽  
Blood Patch ◽  
History Of ◽  
The Difference

Purpose A common complication of lumbar puncture (LP) is postural headaches. Epidural blood patches are recommended if patients fail conservative management. Owing to a perceived increase in the number of post-lumbar puncture headaches (PLPHs) requiring epidural blood patches at a regional hospital in our network, the decision was made to switch from 20 to 22 gauge needles for routine diagnostic LPs. Materials and methods Patients presenting for LP and myelography at one network regional hospital were included in the study. The patients were contacted by nursing staff 3 days post-procedure; those patients who still had postural headaches after conservative management and received epidural blood patches were considered positive cases. In total, 292 patients were included; 134 underwent LP with 20-gauge needles (53 male, 81 female, average age 57.7) and 158 underwent LP with 22-gauge needles (79 male, 79 female, average age 54.6). Results Of 134 patients undergoing LP with 20-gauge needles, 15 (11%) had PLPH requiring epidural blood patch (11 female, 3 male, average age 38). Of 158 patients undergoing LP with 22-gauge needles, only 5 (3%) required epidural blood patches (all female, average age 43). The difference was statistically significant ( p < 0.01). Risk factors for PLPH included female gender, younger age, lower body mass index, history of prior PLPH and history of headaches. Conclusion Switching from 20-gauge to 22-gauge needles significantly decreased the incidence of PLPH requiring epidural blood patch. Narrower gauge or non-cutting needles should be considered in patients with risk factors for PLPH, allowing for CSF requirements.

scholarly journals Detection of New Translocation in Infant Twins with Concordant ALL and Discordant Outcome

2020 ◽  
Vol 13 (1) ◽  
pp. 9-14
Author(s):  
Golamreza Bahoush ◽  
Maryam Vafapour ◽  
Roxana Kariminejad
Keyword(s):  
Gene Rearrangement ◽  
Cytogenetic Study ◽  
Lymphoblastic Leukemia ◽  
Monozygotic Twins ◽  
Protective Role ◽  
Genetic Studies ◽  
Cytogenetic Testing ◽  
The Difference ◽  
Special Case ◽  
Mll Gene Rearrangement

About 2–5% of acute lymphoblastic leukemia (ALL) cases in pediatric patients are infants with an unfavorable prognosis because of high relapse probability. Early detection of the disease is, therefore, very important. Despite the fact that leukemia in twins occurs rarely, more attention has been paid to it in genetic studies. In the present study, through cytogenetic testing, a special case of concordant ALL in monozygotic twins was presented with different outcomes. In spite of an acceptable initial consequence to medical treatment in twins, in another brother (Twin B), early relapse was observed. In the cytogenetic study, both twins expressed t (4; 11) (q21; q23) while twin A expressed t (2; 7) (p10; q10). No cases have previously reported this mutation. Whether this translocation has a protective role for leukemia with mixed-lineage leukemia (MLL) gene rearrangement is still unclear. The difference in the translocation identified in the identical twins is also subject to further investigations.

scholarly journals A Variance Gamma model for Rugby Union matches

2020 ◽  
Vol 17 (1) ◽  
pp. 67-75
Author(s):  
John Fry ◽  
Oliver Smart ◽  
Jean-Philippe Serbera ◽  
Bernhard Klar
Keyword(s):  
Three Dimensional ◽  
Rugby Union ◽  
Three Dimensional Model ◽  
Gamma Model ◽  
Variance Gamma ◽  
Poisson Models ◽  
History Of ◽  
Bonus Points ◽  
Variance Gamma Model ◽  
Special Case

Abstract Amid much recent interest we discuss a Variance Gamma model for Rugby Union matches (applications to other sports are possible). Our model emerges as a special case of the recently introduced Gamma Difference distribution though there is a rich history of applied work using the Variance Gamma distribution – particularly in finance. Restricting to this special case adds analytical tractability and computational ease. Our three-dimensional model extends classical two-dimensional Poisson models for soccer. Analytical results are obtained for match outcomes, total score and the awarding of bonus points. Model calibration is demonstrated using historical results, bookmakers’ data and tournament simulations.

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