Articles de revues sur le sujet « Back-of-the-envelope calculations »
Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Back-of-the-envelope calculations.
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Back-of-the-envelope calculations ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Denning, Peter J. « Back of the envelope ». Communications of the ACM 64, no 9 (septembre 2021) : 35–37. http://dx.doi.org/10.1145/3473612.
Texte intégral
2
Aspinall, R. J., J. A. Miller et J. Franklin. « Calculations on the back of a climate envelope : Addressing the geography of species distributions ». Proceedings of the National Academy of Sciences 106, no 16 (15 avril 2009) : E44. http://dx.doi.org/10.1073/pnas.0809891106.
Texte intégral
3
Arora, A., T. DebRoy et H. K. D. H. Bhadeshia. « Back-of-the-envelope calculations in friction stir welding – Velocities, peak temperature, torque, and hardness ». Acta Materialia 59, no 5 (mars 2011) : 2020–28. http://dx.doi.org/10.1016/j.actamat.2010.12.001.
Texte intégral
4
Löfgren, Karl-Gustaf. « A back of the envelope calculation method for calculations of the gains from genetic progress in forestry with some theoretical underpinning ». Ecological Modelling 92, no 2-3 (décembre 1996) : 245–52. http://dx.doi.org/10.1016/0304-3800(95)00174-3.
Texte intégral
5
Dessus, Sébastien, Santiago Herrera et Rafael de Hoyos. « The impact of food inflation on urban poverty and its monetary cost : some back-of-the-envelope calculations ». Agricultural Economics 39 (novembre 2008) : 417–29. http://dx.doi.org/10.1111/j.1574-0862.2008.00348.x.
Texte intégral
6
Davis, E. « Order of Magnitude Comparisons of Distance ». Journal of Artificial Intelligence Research 10 (1 janvier 1999) : 1–38. http://dx.doi.org/10.1613/jair.520.
Texte intégralRésumé :
Order of magnitude reasoning - reasoning by rough comparisons of the sizes of quantities - is often called `back of the envelope calculation', with the implication that the calculations are quick though approximate. This paper exhibits an interesting class of constraint sets in which order of magnitude reasoning is demonstrably fast. Specifically, we present a polynomial-time algorithm that can solve a set of constraints of the form `Points a and b are much closer together than points c and d.' We prove that this algorithm can be applied if `much closer together' is interpreted either as referring to an infinite difference in scale or as referring to a finite difference in scale, as long as the difference in scale is greater than the number of variables in the constraint set. We also prove that the first-order theory over such constraints is decidable.
7
Chang, Tom, Joshua Graff Zivin, Tal Gross et Matthew Neidell. « Particulate Pollution and the Productivity of Pear Packers ». American Economic Journal : Economic Policy 8, no 3 (1 août 2016) : 141–69. http://dx.doi.org/10.1257/pol.20150085.
Texte intégralRésumé :
We study the effect of outdoor air pollution on the productivity of indoor workers at a pear-packing factory. Increases in fine particulate matter (PM2.5), a pollutant that readily penetrates indoors, leads to significant decreases in productivity, with effects arising at levels below air quality standards. In contrast, pollutants that do not travel indoors, such as ozone, have little, if any, effect on productivity. This effect of outdoor pollution on indoor worker productivity suggests an overlooked consequence of pollution. Back-of-the-envelope calculations suggest the labor savings from nationwide reductions in PM2.5 generated a sizable fraction of total welfare benefits. (JEL D24, J24, L66, Q13, Q51, Q53)
8
Sanders, Nicholas J., et Alan I. Barreca. « Adaptation to Environmental Change : Agriculture and the Unexpected Incidence of the Acid Rain Program ». American Economic Journal : Economic Policy 14, no 1 (1 février 2022) : 373–401. http://dx.doi.org/10.1257/pol.20190060.
Texte intégralRésumé :
The Acid Rain Program (ARP) cut sulfur dioxide (SO2) emissions from power plants in the United States, with considerable benefits. We show this also reduced ambient sulfate levels, which lowered agriculture productivity through decreased soil sulfur. Using plant-level SO2 emissions and an atmospheric transport model, we estimate the relationship between airborne sulfate levels and yields for corn and soybeans. We estimate crop revenue losses for these two crops at around $1–$1.5 billion per year, with accompanying decreases in land value. Back-of-the-envelope calculations of the costs to replace lost sulfur suggest producer responses were limited and suboptimal. (JEL Q15, Q24, Q53, Q58)
9
Marcus, Michelle. « Going Beneath the Surface : Petroleum Pollution, Regulation, and Health ». American Economic Journal : Applied Economics 13, no 1 (1 janvier 2021) : 72–104. http://dx.doi.org/10.1257/app.20190130.
Texte intégralRésumé :
This paper quantifies the health impacts of petroleum leaks from underground storage tanks, the effectiveness of tank regulation, and the role of information as a policy tool in the same setting. Exposure to a leaking underground storage tank during gestation increases both the probability of low birthweight and preterm birth by 7–8 percent. Compliance with regulations requiring the adoption of preventative technologies mitigated the entire effect of leak exposure on low birthweight, and information increased avoidance and moving among highly educated mothers. Back-of-the-envelope calculations suggest the health benefits of preventative regulations exceed the upgrade cost to facilities. (JEL I12, K32, L71, L78, Q35, Q51, Q53)
10
Hungerman, Daniel M. « Substitution and Stigma : Evidence on Religious Markets from the Catholic Sex Abuse Scandal ». American Economic Journal : Economic Policy 5, no 3 (1 août 2013) : 227–53. http://dx.doi.org/10.1257/pol.5.3.227.
Texte intégralRésumé :
This paper considers substitution between charitable activities in the context of religious practice by examining the Catholic Church sex abuse scandal's impact on both Catholic and non-Catholic religiosity. I find a fall in the Catholic population compensated by increases in non-Catholic participation and nonaffiliation. Back-of-the-envelope calculations suggest the scandal generated about $3 billion dollars in donations to non-Catholic faiths. Those leaving Catholicism frequently chose dissimilar alternatives: Baptist churches gained significantly while the Episcopal Church did not. These results challenge several theories of religiosity and suggest that policies or shocks specific to one religious group could have effects on other groups. (JEL D64, Z12)
11
Ärlebäck, Jonas Bergman, et Lluís Albarracín. « FPAT—A Framework for Facilitating the Teaching and Learning of Using Fermi Problems Originating in Mathematics Education Research ». Physics Teacher 60, no 7 (octobre 2022) : 569–71. http://dx.doi.org/10.1119/5.0040017.
Texte intégralRésumé :
Enrico Fermi is remembered for his many contributions to theoretical and experimental physics, but from an educational point of view he also popularized the use of the kind of questions we now call “Fermi problems” (or “Fermi questions”). Fermi problems (FPs) are back-of-envelope problems that arose from the need to make order of magnitude calculations, and Fermi himself used them in his own research and physics classes. The procedure proposed by Fermi was to break the original problem down into simpler sub-problems, solve these by making reasonable estimates and educated guesses, and thereby reach a solution to the original question. In the literature, this way of working is known as the “Fermi (estimates) method.”
12
Zivin, Joshua Graff, Matthew Neidell et Wolfram Schlenker. « Water Quality Violations and Avoidance Behavior : Evidence from Bottled Water Consumption ». American Economic Review 101, no 3 (1 mai 2011) : 448–53. http://dx.doi.org/10.1257/aer.101.3.448.
Texte intégralRésumé :
We examine the impact of poor water quality on avoidance behavior by estimating the change in bottled water purchases in response to drinking water violations. Using data from a national grocery chain matched with water quality violations, we find an increase in bottled water sales of 22 percent from violations due to microorganisms and 17 percent from violations due to elements and chemicals. Back-of-the envelope calculations yield costs of avoidance behavior at roughly $60 million for all nationwide violations in 2005, which likely reflects a significant understatement of the total willingness to pay to eliminate violations.
13
Teltser, Keith F. « Do Kidney Exchanges Improve Patient Outcomes ? » American Economic Journal : Economic Policy 11, no 3 (1 août 2019) : 427–53. http://dx.doi.org/10.1257/pol.20170678.
Texte intégralRésumé :
In this paper, I estimate the number of additional transplants generated by kidney exchanges. To do this, I analyze substitution patterns between exchange transplants and other transplant outcomes. Exploiting variation in patients exposure to exchange activity across time and place, I find that 64 percent of exchange transplants represent new living donor transplants. Using the same approach, I find that an increase in the probability of receiving an exchange transplant reduces the probability of graft failure and reduces time spent waiting for a kidney. Back-of-the-envelope calculations suggest that each exchange transplant increases social welfare by $300,000 to $700,000. (JEL D47, I11, I12, I18)
14
Beraja, Martin, Erik Hurst et Juan Ospina. « The Aggregate Implications of Regional Business Cycles ». Econometrica 87, no 6 (2019) : 1789–833. http://dx.doi.org/10.3982/ecta14243.
Texte intégralRésumé :
Making inferences about aggregate business cycles from regional variation alone is difficult because of economic channels and shocks that differ between regional and aggregate economies. However, we argue that regional business cycles contain valuable information that can help discipline models of aggregate fluctuations. We begin by documenting a strong relationship across U.S. states between local employment and wage growth during the Great Recession. This relationship is much weaker in U.S. aggregates. Then, we present a methodology that combines such regional and aggregate data in order to estimate a medium‐scale New Keynesian DSGE model. We find that aggregate demand shocks were important drivers of aggregate employment during the Great Recession, but the wage stickiness necessary for them to account for the slow employment recovery and the modest fall in aggregate wages is inconsistent with the flexibility of wages we observe across U.S. states. Finally, we show that our methodology yields different conclusions about the causes of aggregate employment and wage dynamics between 2007 and 2014 than either estimating our model with aggregate data alone or performing back‐of‐the‐envelope calculations that directly extrapolate from well‐identified regional elasticities.
15
Beris, A. N., J. A. Tsamopoulos, R. C. Armstrong et R. A. Brown. « Creeping motion of a sphere through a Bingham plastic ». Journal of Fluid Mechanics 158 (septembre 1985) : 219–44. http://dx.doi.org/10.1017/s0022112085002622.
Texte intégralRésumé :
A solid sphere falling through a Bingham plastic moves in a small envelope of fluid with shape that depends on the yield stress. A finite-element/Newton method is presented for solving the free-boundary problem composed of the velocity and pressure fields and the yield surfaces for creeping flow. Besides the outer surface, solid occurs as caps at the front and back of the sphere because of the stagnation points in the flow. The accuracy of solutions is ascertained by mesh refinement and by calculation of the integrals corresponding to the maximum and minimum variational principles for the problem. Large differences from the Newtonian values in the flow pattern around the sphere and in the drag coefficient are predicted, depending on the dimensionless value of the critical yield stress Yg below which the material acts as a solid. The computed flow fields differ appreciably from Stokes’ solution. The sphere will fall only when Yg is below 0.143 For yield stresses near this value, a plastic boundary layer forms next to the sphere. Boundary-layer scalings give the correct forms of the dependence of the drag coefficient and mass-transfer coefficient on yield stress for values near the critical one. The Stokes limit of zero yield stress is singular in the sense that for any small value of Yg there is a region of the flow away from the sphere where the plastic portion of the viscosity is at least as important as the Newtonian part. Calculations For the approach of the flow field to the Stokes result are in good agreement with the scalings derived from the matched asymptotic expansion valid in this limit.
16
Hoffer, András, Aida Meiramova, Ádám Tóth, Beatrix Jancsek-Turóczi, Gyula Kiss, Ágnes Rostási, Erika Andrea Levei, Luminita Marmureanu, Attila Machon et András Gelencsér. « Assessment of the contribution of residential waste burning to ambient PM10 concentrations in Hungary and Romania ». Atmospheric Chemistry and Physics 24, no 3 (6 février 2024) : 1659–71. http://dx.doi.org/10.5194/acp-24-1659-2024.
Texte intégralRésumé :
Abstract. The illegal burning of solid waste in residential stoves is an existing practice, but until now it has been completely disregarded as an emission source of atmospheric pollutants in many developed countries, including those in eastern Europe. Various types of solid waste (plastics, treated wood, plyboards, tyre, rag) serve as an auxiliary fuel in many households, in particular during the heating season. In this work, for the first time ever in atmospheric pollution studies, specific tracer compounds identified previously in controlled test burnings of different waste types in the laboratory were detected and quantified in ambient PM10 samples collected in five Hungarian and four Romanian settlements. Using the identified tracers and their experimentally determined relative emission factors, the potential contribution of illegal waste burning emissions to ambient PM10 mass concentrations was assessed. Our findings implied that the burning of polyethylene terephthalate (PET)-containing waste (food and beverage packaging, clothes) was predominant at all the locations, especially in north-eastern Hungary and Romania. There is substantial evidence that the burning of scrap furniture is also common in big cities in Hungary and Romania. Back-of-the-envelope calculations based on the relative emission factors of individual tracers suggested that the contribution of solid waste burning particulate emissions to ambient PM10 mass concentrations may be as high as a few percent. This finding, when considering the extreme health hazards associated with particulate emissions from waste burning, is a matter of serious public health concern.
17
Lee, Franklin Langlang, Jaehong Park, Sushmit Goyal, Yousef Qaroush, Shihu Wang, Hong Yoon, Aravind Rammohan et Youngseon Shim. « Comparison of Machine Learning Methods towards Developing Interpretable Polyamide Property Prediction ». Polymers 13, no 21 (23 octobre 2021) : 3653. http://dx.doi.org/10.3390/polym13213653.
Texte intégralRésumé :
Polyamides are often used for their superior thermal, mechanical, and chemical properties. They form a diverse set of materials that have a large variation in properties between linear to aromatic compounds, which renders the traditional quantitative structure–property relationship (QSPR) challenging. We use extended connectivity fingerprints (ECFP) and traditional QSPR fingerprints to develop machine learning models to perform high fidelity prediction of glass transition temperature (Tg), melting temperature (Tm), density (ρ), and tensile modulus (E). The non-linear model using random forest is in general found to be more accurate than linear regression; however, using feature selection or regularization, the accuracy of linear models is shown to be improved significantly to become comparable to the more complex nonlinear algorithm. We find that none of the models or fingerprints were able to accurately predict the tensile modulus E, which we hypothesize is due to heterogeneity in data and data sources, as well as inherent challenges in measuring it. Finally, QSPR models revealed that the fraction of rotatable bonds, and the rotational degree of freedom affects polyamide properties most profoundly and can be used for back of the envelope calculations for a quick estimate of the polymer attributes (glass transition temperature, melting temperature, and density). These QSPR models, although having slightly lower prediction accuracy, show the most promise for the polymer chemist seeking to develop an intuition of ways to modify the chemistry to enhance specific attributes.
18
Torres, Mark A., Nils Moosdorf, Jens Hartmann, Jess F. Adkins et A. Joshua West. « Glacial weathering, sulfide oxidation, and global carbon cycle feedbacks ». Proceedings of the National Academy of Sciences 114, no 33 (31 juillet 2017) : 8716–21. http://dx.doi.org/10.1073/pnas.1702953114.
Texte intégralRésumé :
Connections between glaciation, chemical weathering, and the global carbon cycle could steer the evolution of global climate over geologic time, but even the directionality of feedbacks in this system remain to be resolved. Here, we assemble a compilation of hydrochemical data from glacierized catchments, use this data to evaluate the dominant chemical reactions associated with glacial weathering, and explore the implications for long-term geochemical cycles. Weathering yields from catchments in our compilation are higher than the global average, which results, in part, from higher runoff in glaciated catchments. Our analysis supports the theory that glacial weathering is characterized predominantly by weathering of trace sulfide and carbonate minerals. To evaluate the effects of glacial weathering on atmospheric pCO2, we use a solute mixing model to predict the ratio of alkalinity to dissolved inorganic carbon (DIC) generated by weathering reactions. Compared with nonglacial weathering, glacial weathering is more likely to yield alkalinity/DIC ratios less than 1, suggesting that enhanced sulfide oxidation as a result of glaciation may act as a source of CO2 to the atmosphere. Back-of-the-envelope calculations indicate that oxidative fluxes could change ocean–atmosphere CO2 equilibrium by 25 ppm or more over 10 ky. Over longer timescales, CO2 release could act as a negative feedback, limiting progress of glaciation, dependent on lithology and the concentration of atmospheric O2. Future work on glaciation–weathering–carbon cycle feedbacks should consider weathering of trace sulfide minerals in addition to silicate minerals.
19
Götz, Georg, Daniel Herold, Phil-Adrian Klotz et Jan Thomas Schäfer. « Efficiency in COVID-19 Vaccination Campaigns—A Comparison across Germany’s Federal States ». Vaccines 9, no 7 (14 juillet 2021) : 788. http://dx.doi.org/10.3390/vaccines9070788.
Texte intégralRésumé :
Vaccination programs are considered a central pillar of the efforts to stop COVID-19. However, vaccine doses are scarce and several organizational and logistical obstacles, such as the timing of and reserves for second shots and delivery failures, apparently slow down vaccination roll-outs in several countries. Moreover, it is an open question as to where vaccines are administered as efficiently as possible (vaccination centers, hospitals, doctor’s offices, pharmacists, etc.). The first aim of our study was to systematically evaluate the efficiency of a country’s vaccination campaign. The second aim was to analyze how the integration of doctors’ offices into a campaign that formerly relied only on vaccination centers affected the speed of that campaign. Using data on vaccine deliveries and vaccinations given in Germany, we find considerable differences across federal states in terms of efficiency, defined as the ability to administer the most vaccinations out of a given number of available doses. Back-of-the-envelope calculations for January to May 2021 show that vaccinations would have been 3.4–6.9% higher if all federal states had adopted a similar ratio between vaccinations given and vaccines stored, as the most efficient states did. This corresponds to 1.7–3.3% of Germany’s total population. In terms of our second research goal, we find evidence that the integration of doctors’ offices into the vaccination campaign significantly increased the ratio of vaccinations administered out of a given stock of vaccine doses. On average, there appears to be a structural break in this ratio after doctors’ offices were integrated into the vaccination campaign on 5 April 2021. On average, an additional 11.6 out of 100 available doses were administered each week compared to the period prior to that date. We conclude that there are considerable regional differences in the efficiency of the vaccination roll-out. Systematic efficiency analyses are one step to detecting inefficiencies and to identify best practices that can be adopted to eventually speed up the vaccination roll-out in a country.
20
Jenkin, Robin, et Cheng Zhao. « Radiometry and Photometry for Autonomous Vehicles and Machines - Fundamental Performance Limits ». Electronic Imaging 2021, no 17 (18 janvier 2021) : 211–1. http://dx.doi.org/10.2352/issn.2470-1173.2021.17.avm-211.
Texte intégralRésumé :
As autonomous vehicles and machines, such as self-driving cars, agricultural drones and industrial robots, become ubiquitous, there is an increasing need to understand the objective performance of cameras to support these functions. Images go beyond aesthetic and subjective roles as they assume increasing aspects of control, safety, and diagnostic capabilities. Radiometry and photometry are fundamental to describing the behavior of light and modeling the signal chain for imaging systems, and as such, are crucial for establishing objective behavior. As an engineer or scientist, having an intuitive feel for the magnitude of units and the physical behavior of components or systems in any field improves development capabilities and guards against rudimentary errors. Back-of-the-envelope estimations provide comparisons against which detailed calculations may be tested and will urge a developer to “try again” if the order of magnitude is off for example. They also provide a quick check for the feasibility of ideas, a “giggle” or “straight-face” test as it is sometimes known. This paper is a response to the observation of the authors that, amongst participants that are newly relying on the imaging field and existing image scientists alike, there is a general deficit of intuition around the units and order of magnitude of signals in typical cameras for autonomous vehicles and the conditions within which they operate. Further, there persists a number of misconceptions regarding general radiometric and photometric behavior. Confusion between the inverse square law as applied to illumination and consistency of image luminance versus distance is a common example. The authors detail radiometric and photometric model for an imaging system, using it to clarify vocabulary, units and behaviors. The model is then used to estimate the number of quanta expected in pixels for typical imaging systems for each of the patches of a MacBeth color checker under a wide variety of illumination conditions. These results form the basis to establish the fundamental limits of performance for passive camera systems based both solely on camera geometry and additionally considering typical quantum efficiencies available presently. Further a mental model is given which will quickly allow user to estimate numbers of photoelectrons in pixel.
21
Tam, Derrick Y., et Mario Gaudino. « Commentary : When the back of the envelope calculation just isn't good enough, use decision analysis modeling ». Journal of Thoracic and Cardiovascular Surgery 159, no 6 (juin 2020) : 2243–44. http://dx.doi.org/10.1016/j.jtcvs.2019.06.094.
Texte intégral
22
Slacalek, Jiri, Oreste Tristani et Giovanni L. Violante. « Household balance sheet channels of monetary policy : A back of the envelope calculation for the euro area ». Journal of Economic Dynamics and Control 115 (juin 2020) : 103879. http://dx.doi.org/10.1016/j.jedc.2020.103879.
Texte intégral
23
Lovejoy, S., D. Schertzer et A. F. Tuck. « Why anisotropic turbulence matters : another reply ». Atmospheric Chemistry and Physics Discussions 10, no 3 (23 mars 2010) : 7495–506. http://dx.doi.org/10.5194/acpd-10-7495-2010.
Texte intégralRésumé :
Abstract. We continue the debate on anisotropic but scaling turbulence and its effect on aircraft measurements of turbulence (cf. Lindborg et al., 2010a, b); hereafter LTNCG1, LTNCG2). We revisit the repeatedly presented back-of-the-envelope calculation and discuss wind statistics on real isobars. We then discuss theoretical and empirical evidence that a k−5/3 horizontal wind spectrum could extend out to planetary scales.
24
Luetticke, Ralph. « Comment on “The Household Channel of Monetary Policy in the Euro Area : A Back of the Envelope Calculation” ». Journal of Economic Dynamics and Control 115 (juin 2020) : 103880. http://dx.doi.org/10.1016/j.jedc.2020.103880.
Texte intégral
25
Zhou, Guang Zhu, Xu Wei et Chen Yu. « Study on Stressed Characteristic of Gridding Concrete Retaining Wall Used in Excavation of Soft-Soil Foundation Pit ». Advanced Materials Research 243-249 (mai 2011) : 2266–70. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2266.
Texte intégralRésumé :
As a new type of building envelope, Gcrw is mainly used for excavation of foundation pit. It can stand by itself without the help of bracing, especially in soft soil area. Its stressed characteristic hasn’t been known yet. By using advanced big finite element software Abaqus/Cae, a simulation was made on model of Gcrw under soil pressure when a foundation pit is dug, while the whole excavation is divided into three continuous independent excavation stages. The result shows that Gcrw is a rather good building envelope, Gcrw and soil in the gridding form an integral earth-retaining structure and keep balance under soil pressure before or behind the structure, and have little displacement in horizontal direction. It is like a gravity-type retaining wall in its entirety, but takes on an elastic characteristic. The soil pressure presents a linear change, but its value is less than the theoretical value of calculation. The front wall of Gcrw, like a sheet, is the main flexural construction element, which is subjected to the pressure from side wall of foundation pit and produce curve deformation. The back wall of Gcrw has little displacement and almost is built in the clay. The partition wall endures the effect of the tensile force, its horizontal deformation increases with the build-in depth’s increasing. The back wall and the partition wall play a very important role in dragging back the front wall, the role of them is similar to a pair of anchor tie. The soil in the gridding not only provides soil pressure, but also can fix the back wall, so it is seen as a part of Gcrw and in favor of the Gcrw’s anti-overturn.
26
CHO, SUNGJIN, JIHYE KAM et SOOHYUNG LEE. « EFFICIENT SUPPLY OF HUMAN CAPITAL : ROLE OF COLLEGE MAJOR ». Singapore Economic Review 63, no 05 (décembre 2018) : 1319–43. http://dx.doi.org/10.1142/s0217590817500047.
Texte intégralRésumé :
This study examines the extent to which changing the composition of college majors among working-age population may affect the supply of human capital or effective labor supply. We use the South Korean setting, in which the population is rapidly aging, but where, despite their high educational attainment, women and young adults are still weakly attached to the labor market. We find that engineering majors have an advantage in various outcomes such as likelihood of being in the labor force, being employed, obtaining long-term position, and earnings, while Humanities and Arts/Athletics majors show the worst outcomes. We then conduct a back-of-the-envelope calculation of the impact of the recently proposed policy change to increase the share of engineering majors by 10% starting in 2017. Our calculation suggests that the policy change may have a positive but small impact on labor market outcomes.
27
Balázs, Csaba. « Free Scalar Fields in Finite Volume Are Holographic ». Universe 5, no 12 (4 décembre 2019) : 223. http://dx.doi.org/10.3390/universe5120223.
Texte intégralRésumé :
This brief note presents a back-of-the-envelope calculation showing that the number of degrees of freedom of a free scalar field in expanding flat space equals the surface area of the Hubble volume in Planck units. The logic of the calculation is the following. The amount of energy in the Hubble volume scales with its linear size, consequently the volume can only contain a finite number of quantized field modes. Since the momentum of the lowest energy mode scales inversely with the linear size of the volume, the maximal number of such modes in the volume scales with its surface area. It is possible to show that when the number of field modes is saturated the modes are confined to the surface of the volume. Gravity only enters this calculation as a regulator, providing a finite volume that contains the field, the entire calculation is done in flat space. While this toy model is bound to be incomplete, it is potentially interesting because it reproduces the defining aspects of holography, and advocates a regularization of the quantum degrees of freedom based on Friedmann’s equation.
28
Cannonier, Colin, et Monica Galloway Burke. « The economic growth impact of tourism in Small Island Developing States—evidence from the Caribbean ». Tourism Economics 25, no 1 (7 août 2018) : 85–108. http://dx.doi.org/10.1177/1354816618792792.
Texte intégralRésumé :
Tourism’s contribution to economic output in the Caribbean exceeds that in other regions of the world. We use panel data over the period of three decades, focusing exclusively on Caribbean islands, to study the causal link between tourism and economic growth. The results show that tourism has a positive and statistically significant effect on real Gross Domestic Product growth. A 10% increase in tourism spending is found to increase economic growth from 0.3% to 1%, a finding that is consistent with similar studies. A simple back-of-the-envelope calculation suggests that the overall tourism multiplier is around 0.25 which is smaller than estimates from previous studies. These results have important implications for researchers, industry practitioners, and policymakers.
29
Jayachandran, Seema, et Rohini Pande. « Why Are Indian Children So Short ? The Role of Birth Order and Son Preference ». American Economic Review 107, no 9 (1 septembre 2017) : 2600–2629. http://dx.doi.org/10.1257/aer.20151282.
Texte intégralRésumé :
Child stunting in India exceeds that in poorer regions like sub-Saharan Africa. Data on over 168,000 children show that, relative to Africa, India's height disadvantage increases sharply with birth order. We posit that India's steep birth order gradient is due to favoritism toward eldest sons, which affects parents' fertility decisions and resource allocation across children. We show that, within India, the gradient is steeper for high-son-preference regions and religions. The gradient also varies with sibling gender as predicted. A back-of-the-envelope calculation suggests that India's steeper birth order gradient can explain over one-half of the India-Africa gap in average child height. (JEL C61, D72, D82, D83, K10, M11)
30
Schinkel, Maarten Pieter. « Effective Cartel Enforcement in Europe ». World Competition 30, Issue 4 (1 décembre 2007) : 539–72. http://dx.doi.org/10.54648/woco2007038.
Texte intégralRésumé :
The European Commission has made clear in a number of recent publications that undertakings that collude to fix prices or share markets should expect fines based on affected commerce, as well as private antitrust damage claims. Research on discovered cartels characterises a modern international cartel in terms of illegal gains, duration of the infringement and success on appeal. This article offers a back-of-the-envelope calculation into the net effective (expected) liability of a representative modern international cartel in Europe. To that end, the history of European cartel enforcement is surveyed in summary statistics. The exercise leads to the conclusion that the European Commission’s recent commitments to punishing cartels are likely to remain insufficient to deter collusion, unless European enforcement also produces a high (perceived) probability of discovery across the board. This calls for active cartel detection.
31
Van Hemert, Mieke. « Speculative promise as a driver in climate engineering research : The case of Paul Crutzen’s back-of-the-envelope calculation on solar dimming with sulfate aerosols ». Futures 92 (septembre 2017) : 80–89. http://dx.doi.org/10.1016/j.futures.2016.11.006.
Texte intégral
32
Chen, Zhiwei, Yuxue Ge, Jie Yuan et Yang Pei. « Gliding Footprint Calculation Method for Aircraft with Thrust Failure Based on Six-Degree-of-Freedom Flight Envelope and Back-Propagation Artificial Neural Network ». Aerospace 11, no 2 (16 février 2024) : 160. http://dx.doi.org/10.3390/aerospace11020160.
Texte intégralRésumé :
In hostile environments, engine damage is of particular concern since the engine is the only component to generate thrust that affects survivability. For an aircraft suffering thrust failure, the forced landing sites should be identified within the gliding footprint, which is the reachable region on the ground. This paper proposes two calculation methods to obtain the gliding footprint by finding a series of boundary points with maximum gliding distance around the aircraft. Method 1 models the thrust-failed aircraft with six-degree-of-freedom (6-DOF) flight dynamics and adopts a novel 6-DOF unpowered-flight envelope to characterize its maneuvering capabilities. Given the initial altitude when thrust failure occurs, Method 1 determines all feasible gliding distances around the aircraft based on the constructed 6-DOF flight envelope and selects the landing points of maximum gliding distances along different radial directions as the boundary points. Method 2 employs the Back-Propagation Artificial Neural Network (BP-ANN) to predict the boundary points. Using the well-trained BP-ANN, this method can estimate the maximum gliding distances with only the initial altitude and radial directions. Simulations are conducted to analyze these two methods. Compared with conventional methods using point-mass flight dynamics, Method 1 considers more flight constraints, and the gliding footprint area is reduced by 20.79%. These results are relatively conservative and can improve the safety threshold of forced landing sites. Method 2 can estimate the gliding footprints (encircled by the boundary points under the entire operational altitude and full radial direction) in real time, which reserves more response and action time for aircraft forced landing.
33
Horton, John J. « Buyer Uncertainty About Seller Capacity : Causes, Consequences, and a Partial Solution ». Management Science 65, no 8 (août 2019) : 3518–40. http://dx.doi.org/10.1287/mnsc.2018.3116.
Texte intégralRésumé :
Employers in an online labor market often pursue workers with little capacity to take on more work. The pursuit of low-capacity workers is consequential, as these workers are more likely to reject employer inquires, causing a reduction in the probability that a job opening is ultimately filled. In an attempt to shift more employer attention to workers with greater capacity, the market-designing platform examined in this paper introduced a new signaling feature into the market. It was effective, in that when a worker signaled having high capacity, he or she received more invitations from employers, rejected a smaller fraction of those invitations, quoted lower prices to do the work, and was more likely to be hired. A back-of-the-envelope calculation suggests the signaling feature alone could increase market surplus by as much as 6%, both by increasing the number of matches formed and by helping to allocate projects to workers with lower costs. This paper was accepted by Lorin Hitt, information systems.
34
Irfan, Muhammad, Michael P. Cameron et Gazi Hassan. « The Causal Impact of Solid Fuel Use on Mortality – A Cross- Country Panel Analysis ». International Journal of Energy Economics and Policy 13, no 1 (22 janvier 2023) : 144–53. http://dx.doi.org/10.32479/ijeep.13498.
Texte intégralRésumé :
Biomass consumption causes indoor air pollution which impairs health and environment. In this paper, we examine the causal relationship between biomass fuel consumption and measures of life expectancy and infant and child mortality. Using 13 years of cross-country panel data which covers 105 countries over the period 2000-2012, we applied fixed effect model and instrumental variable regression. We find that solid fuel combustion causes increase in infant and child mortality and decreases in male and female life expectancy. A back-of-the envelope calculation suggests that, if the solid fuel consumption gap between low-income and lower-middle income countries were reduced by 50 percent, infant and child mortality in the low-income countries decrease by 16.5 and 29.8 per thousand respectively, and life expectancy would increase by 1.0 and 1.5 years for males and females respectively. Our findings suggest that governments, particularly of developing countries, should focus efforts to reduce solid fuel use.
35
Cawkwell, Thomas, Ahmed Haris, Juan Manuel Gonzalez, Leon Kevin Rodrigues et Vladimir Shirokov. « A Methodology for Applying Skew in an Automotive Interior Permanent Magnet Rotor for Robust Electromagnetic and Noise, Vibration and Harshness Performance ». World Electric Vehicle Journal 14, no 12 (15 décembre 2023) : 350. http://dx.doi.org/10.3390/wevj14120350.
Texte intégralRésumé :
Interior permanent magnet (IPM) motors in traction applications often employ discrete rotor skewing constructions to reduce torsional excitations and back-EMF harmonics. Although skewing is very effective in reducing cogging torque, the impact on torque ripple is not well understood and can vary significantly over the operating envelope of a motor. Skewing also leads to the creation of a non-zero axial force that may compromise the bearing life if not considered. This paper introduces a holistic methodology for analyzing the effect of skewing, aiming to minimize torsional excitations, axial forces and back-EMF harmonics whilst mitigating the impact on performance and costs. Firstly, analytical models are employed for calculating cogging torque, torque ripple and axial forces. Then, 2D and 3D finite element analysis are used to incorporate the influence of non-linear material behavior. A detailed structural model of the powertrain is employed to calculate the radiated noise and identify key areas allowing a motor designer to reduce noise, vibration and harshness (NVH). A meticulous selection process for the skewing angle, the number of skew stacks and the orientation of skew stacks is developed, giving particular attention to the effect of the selected pattern on NVH in both forward and reverse rotating directions.
36
Hede, Thomas, Caroline Leck et Jonas Claesson. « Amplified Feedback Mechanism of the Forests-Aerosols-Climate System ». Journal of Climatology 2015 (9 avril 2015) : 1–11. http://dx.doi.org/10.1155/2015/262980.
Texte intégralRésumé :
Climate change very likely has effects on vegetation so that trees grow faster due to carbon dioxide fertilization (a higher partial pressure increases the rate of reactions with Rubisco during photosynthesis) and that trees can be established in new territories in a warmer climate. This has far-reaching significance for the climate system mainly due to a number of feedback mechanisms still under debate. By simulating the vegetation using the Lund-Potsdam-Jena guess dynamic vegetation model, a territory in northern Russia is studied during three different climate protocols assuming a doubling of carbon dioxide levels compared to the year 1975. A back of the envelope calculation is made for the subsequent increased levels of emissions of monoterpenes from spruce and pine forests. The results show that the emissions of monoterpenes at the most northern latitudes were estimated to increase with over 500% for a four-degree centigrade increase protocol. The effect on aerosol and cloud formation is discussed and the cloud optical thickness is estimated to increase more than 2%.
37
Sjöberg, Y., P. Marklund, R. Pettersson et S. W. Lyon. « Geophysical mapping of palsa peatland permafrost ». Cryosphere 9, no 2 (4 mars 2015) : 465–78. http://dx.doi.org/10.5194/tc-9-465-2015.
Texte intégralRésumé :
Abstract. Permafrost peatlands are hydrological and biogeochemical hotspots in the discontinuous permafrost zone. Non-intrusive geophysical methods offer a possibility to map current permafrost spatial distributions in these environments. In this study, we estimate the depths to the permafrost table and base across a peatland in northern Sweden, using ground penetrating radar and electrical resistivity tomography. Seasonal thaw frost tables (at ~0.5 m depth), taliks (2.1–6.7 m deep), and the permafrost base (at ~16 m depth) could be detected. Higher occurrences of taliks were discovered at locations with a lower relative height of permafrost landforms, which is indicative of lower ground ice content at these locations. These results highlight the added value of combining geophysical techniques for assessing spatial distributions of permafrost within the rapidly changing sporadic permafrost zone. For example, based on a back-of-the-envelope calculation for the site considered here, we estimated that the permafrost could thaw completely within the next 3 centuries. Thus there is a clear need to benchmark current permafrost distributions and characteristics, particularly in under studied regions of the pan-Arctic.
38
Mary, Sébastien. « How Much Does Economic Growth Contribute to Child Stunting Reductions ? » Economies 6, no 4 (9 octobre 2018) : 55. http://dx.doi.org/10.3390/economies6040055.
Texte intégralRésumé :
The role of economic growth in reducing child undernutrition remains an open and highly debated question that holds important implications for food security strategies. The empirical evidence has been quite contrasted, primarily in regard to the magnitude of the impacts. Yet, most studies have not (appropriately) accounted for the reverse causality between economic growth and child stunting. Using a dataset of 74 developing countries observed between 1984 and 2014, this paper develops a novel approach accounting for the reverse causal effect of stunting on GDP per capita and finds that the impacts of economic growth are much lower than estimated in most previous studies. A 10% increase in GDP per capita reduces child stunting prevalence by 2.7%. In other words, economic growth is modestly pro-poor. We also estimate that a percentage point increase in child stunting prevalence results in a 0.4% decrease in GDP per capita. A back-of-the-envelope calculation suggests that stunting costs on average about 13.5% of GDP per capita in developing countries.
39
ANDERSON, KYM, WILL MARTIN et ERNESTO VALENZUELA. « The relative importance of global agricultural subsidies and market access ». World Trade Review 5, no 3 (19 octobre 2006) : 357–76. http://dx.doi.org/10.1017/s1474745606002916.
Texte intégralRésumé :
The claim by global trade modelers that the potential contribution to global economic welfare of removing agricultural subsidies is less than one-tenth of that from removing agricultural tariffs puzzles many observers. To help explain that result, this paper first compares the OECD and model-based estimates of the extent of the producer distortions (leaving aside consumer distortions), and shows that 75% of total support is provided by market access barriers when account is taken of all forms of support to farmers and to agricultural processors globally, and only 19% to domestic farm subsidies. We then provide a back-of-the-envelope (BOTE) calculation of the welfare cost of those distortions. Assuming unitary supply and demand elasticities, that BOTE analysis suggests 86% of the welfare cost is due to tariffs and only 6% to domestic farm subsidies. When the higher costs associated with the greater variability of trade measures relative to domestic support are accounted for, the BOTE estimate of the latter's share falls to 4%. This is close to the 5% generated by the most commonly used global model (GTAP) and reported in the paper's final section.
40
Oudiz, Gilles. « European Policy Coordination : An Evaluation ». Recherches économiques de Louvain 51, no 3-4 (décembre 1985) : 301–39. http://dx.doi.org/10.1017/s0770451800082658.
Texte intégralRésumé :
According to the European Community Commission the present level of unemployment in Europe should not only last but worsen in the foreseeable future (see CCE 1984). By 1988 the overall unemployment rate in Europe should reach 11,4% if the « optimistic » assumptions retained for the labor supply are to be realized.These are of course average figures but on the whole they correctly reflect the extraordinary convergence of European deflationary policies. Given structural differences, which remain very limited when one compares them to the other Western economies, the European governments seem to have settled for the same macroeconomic strategies. Of course, they have chosen different timings. France, for example, has grown more than its partners in 1981-1982 but is now experiencing a prolonged recession. Whereas West Germany is doing better as far as GNP is concerned but grew very little in the early 80 s. On the whole however a back of the envelope calculation of « sacrifice ratios » for the leading European economies would yield quite similar results. All over Europe disinflation has been achieved at a high output cost and it is not clear that any country has really done better than its partners.
41
He, Guojun, Shaoda Wang et Bing Zhang. « Watering Down Environmental Regulation in China* ». Quarterly Journal of Economics 135, no 4 (22 juin 2020) : 2135–85. http://dx.doi.org/10.1093/qje/qjaa024.
Texte intégralRésumé :
Abstract This article estimates the effect of environmental regulation on firm productivity using a spatial regression discontinuity design implicit in China's water quality monitoring system. Because water quality readings are important for political evaluations and the monitoring stations only capture emissions from their upstream regions, local government officials are incentivized to enforce tighter environmental standards on firms immediately upstream of a monitoring station, rather than those immediately downstream. Exploiting this discontinuity in regulation stringency with novel firm-level geocoded emission and production data sets, we find that immediate upstream polluters face a more than 24% reduction in total factor productivity (TFP), and a more than 57% reduction in chemical oxygen demand emissions, as compared with their immediate downstream counterparts. We find that the discontinuity in TFP does not exist in nonpolluting industries, only emerged after the government explicitly linked political promotion to water quality readings, and was predominantly driven by prefectural cities with career-driven leaders. Linking the TFP estimate with the emission estimate, a back-of-the-envelope calculation indicates that China's water regulation efforts between 2000 and 2007 were associated with an economic cost of more than 800 billion Chinese yuan.
42
Bozarth, Lia, et Ceren Budak. « Market Forces : Quantifying the Role of Top Credible Ad Servers in the Fake News Ecosystem ». Proceedings of the International AAAI Conference on Web and Social Media 15 (22 mai 2021) : 83–94. http://dx.doi.org/10.1609/icwsm.v15i1.18043.
Texte intégralRésumé :
Larry Lessig argues that four modes regulate behavior in cyberspace: laws, markets, norms, and architecture. How can these four modes regulate the production and spread of fake news? In this paper, we focus on markets and empirically evaluate one particular market-based solution: top ad firms blacklisting fake news producers to eliminate their revenue sources. Our study reveals that fake and low-quality publishers demonstrate a higher tendency to serve more ads and to partner with risky ad servers than traditional news media with similar popularity and age. However, fake news publishers are still strongly reliant on credible ad servers. In fact, the top-10 credible ad servers alone account for 66.7% and 55.6% of fake and low-quality ad traffic respectively. Furthermore, our back-of-the-envelope calculation shows that, at the time of our data collection, the top-10 ad firms were receiving $985.7K to $1.15M monthly from web traffic on fake news sites, a negligible fraction of these firms' annual revenue. Overall, our findings suggest that having top ad firms blacklist known fake and low-quality publishers is a low-cost way to combat fake news.
43
Tatas, Konstantinos. « Performance Analysis of 2D and 3D Bufferless NoCs Using Markov Chain Models ». Technologies 10, no 1 (2 février 2022) : 27. http://dx.doi.org/10.3390/technologies10010027.
Texte intégralRésumé :
Performance analysis and design space exploration of bufferless Networks-on-Chip is done mainly through time-consuming cycle-accurate simulation, due to the chaotic nature of packet deflections, which have thus far prevented the development of an accurate analytical model. In order to raise the level of abstraction as well as capture the inherently probabilistic behavior of deflection routing, this paper presents a methodology for employing Markov chain models in the analysis of the behavior of bufferless Networks-on-Chip. A formal way of describing a bufferless NoC topology as a set of discrete-time Markov chains is presented. It is demonstrated that by combining this description with the network average distance, it is possible to obtain the expectation of the number of hops between any pair of nodes in the network as a function of the flit deflection probability. Comparisons between the proposed model and cycle-accurate simulation demonstrate the accuracy achieved by the model, with negligible computational cost. The useful range of the proposed model is quantified, demonstrating that it has an error of less than 10% for a significant proportion (between 33 and 75%) of the injection rate range below saturation. Finally, a simple equation for comparing mesh topologies with a “back-of-the-envelope” calculation is introduced.
44
Lin, Yaolin, Luqi Zhao, Xiaohong Liu, Wei Yang, Xiaoli Hao et Lin Tian. « Design Optimization of a Passive Building with Green Roof through Machine Learning and Group Intelligent Algorithm ». Buildings 11, no 5 (2 mai 2021) : 192. http://dx.doi.org/10.3390/buildings11050192.
Texte intégralRésumé :
This paper proposed an optimization method to minimize the building energy consumption and visual discomfort for a passive building in Shanghai, China. A total of 35 design parameters relating to building form, envelope properties, thermostat settings, and green roof configurations were considered. First, the Latin hypercube sampling method (LHSM) was used to generate a set of design samples, and the energy consumption and visual discomfort of the samples were obtained through computer simulation and calculation. Second, four machine learning prediction models, including stepwise linear regression (SLR), back-propagation neural networks (BPNN), support vector machine (SVM), and random forest (RF) models, were developed. It was found that the BPNN model performed the best, with average absolute relative errors of 3.27% and 1.25% for energy consumption and visual comfort, respectively. Third, six optimization algorithms were selected to couple with the BPNN models to find the optimal design solutions. The multi-objective ant lion optimization (MOALO) algorithm was found to be the best algorithm. Finally, optimization with different groups of design variables was conducted by using the MOALO algorithm with the associated outcomes being analyzed. Compared with the reference building, the optimal solutions helped reduce energy consumption up to 34.8% and improved visual discomfort up to 100%.
45
Coffman, Katherine Baldiga. « Evidence on Self-Stereotyping and the Contribution of Ideas * ». Quarterly Journal of Economics 129, no 4 (12 septembre 2014) : 1625–60. http://dx.doi.org/10.1093/qje/qju023.
Texte intégralRésumé :
Abstract We use a lab experiment to explore the factors that predict an individual’s decision to contribute her idea to a group. We find that contribution decisions depend on the interaction of gender and the gender stereotype associated with the decision-making domain: conditional on measured ability, individuals are less willing to contribute ideas in areas that are stereotypically outside of their gender’s domain. Importantly, these decisions are largely driven by self-assessments, rather than fear of discrimination. Individuals are less confident in gender-incongruent areas and are thus less willing to contribute their ideas. Because even very knowledgeable group members undercontribute in gender-incongruent categories, group performance suffers and, ex post, groups have difficulty recognizing who their most talented members are. Our results show that even in an environment where other group members show no bias, women in male-typed areas and men in female-typed areas may be less influential. An intervention that provides feedback about a woman’s (man’s) strength in a male-typed (female-typed) area does not significantly increase the probability that she contributes her ideas to the group. A back-of-the-envelope calculation reveals that a “lean in”–style policy that increases contribution by women would significantly improve group performance in male-typed domains.
46
Mary, Sebastien, Kyle Craven, Avraham Stoler et Sarah Shafiq. « Revisiting the Impact of Dams on Malaria and Agriculture ». Economies 11, no 7 (25 juin 2023) : 173. http://dx.doi.org/10.3390/economies11070173.
Texte intégralRésumé :
We estimate the effect of large dams on malaria incidence in India between 1975 and 1995. We combine instrumental variables approach with a panel model with unobserved common factors allowing us to fully capture the endogeneity of dam location and unobserved time-varying heterogeneity. Dams result in increased malaria incidence in districts where dams are located and in downstream areas. We find that the construction of a large dam increases a district’s annual malaria incidence by about 0.9 to 1.4 percent, and by about 1 to 1.5 percent in downstream districts. We also find that this malaria-increasing effect of dams persists over time. Our results imply that the construction of dams in malaria-sensitive areas should be coupled with direct interventions, such as the wide deployment of insecticide-treated nets or the roll-out of future vaccines. Furthermore, we examine the contribution of agricultural development to this malaria-increasing effect of dams. We find that dam construction benefits agriculture in the vicinity of dams, as well as in downstream areas. These positive effects are driven by increased irrigation and cultivation in the vicinity of dams, while they are driven by changes in cropping patterns in downstream areas, where the cultivation of high-yielding variety crops increases. Finally, a back-of-the-envelope calculation suggests that the agricultural production gains from dam construction dominate the economic losses resulting from increased malaria.
47
Mittmann, Nicole, Soo Jin Seung, Michael D. Hill, Stephen J. Phillips, Vladimir Hachinski, Robert Coté, Brian H. Buck et al. « Impact of Disability Status on Ischemic Stroke Costs in Canada in the First Year ». Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 39, no 6 (novembre 2012) : 793–800. http://dx.doi.org/10.1017/s0317167100015638.
Texte intégralRésumé :
Background:Longitudinal, patient-level data on resource use and costs after an ischemic stroke are lacking in Canada. The objectives of this analysis were to calculate costs for the first year post-stroke and determine the impact of disability on costs.Methodology:The Economic Burden of Ischemic Stroke (BURST) Study was a one-year prospective study with a cohort of ischemic stroke patients recruited at 12 Canadian stroke centres. Clinical history, disability, health preference and resource utilization information was collected at discharge, three months, six months and one year. Resources included direct medical costs (2009 CAN$) such as emergency services, hospitalizations, rehabilitation, physician services, diagnostics, medications, allied health professional services, homecare, medical/assistive devices, changes to residence and paid caregivers, as well as indirect costs. Results were stratified by disability measured at discharge using the modified Rankin Score (mRS): non-disabling stroke (mRS 0-2) and disabling stroke (mRS 3-5).Results:We enrolled 232 ischemic stroke patients (age 69.4 ± 15.4 years; 51.3% male) and 113 (48.7%) were disabled at hospital discharge. The average annual cost was $74,353; $107,883 for disabling strokes and $48,339 for non-disabling strokes.Conclusions:An average annual cost for ischemic stroke was calculated in which a disabling stroke was associated with a two-fold increase in costs compared to NDS. Costs during the hospitalization to three months phase were the highest contributor to the annual cost. A “back of the envelope” calculation using 38,000 stroke admissions and the average annual cost yields $2.8 billion as the burden of ischemic stroke.
48
Kreiseder, Fabian, et Moritz Mosenhauer. « Watching the Watchmen : Assessment-Biases in Waiting List Prioritization for the Delivery of Mental Health Services ». European Journal of Management Issues 30, no 1 (3 mars 2022) : 3–16. http://dx.doi.org/10.15421/192201.
Texte intégralRésumé :
Purpose: While the demand for mental health services increases, supply often stagnates. Providing treatment to those most in need is an important factor in its efficient distribution. We propose and conduct a statistical procedure for detecting rater-biases in patient prioritization tools.
Design / Method / Approach: We gather real-life data from 266 illness severity assessments in an Austrian publicly funded mental health service provider, including a rich set of covariates. To ensure robustness, we merge this data with determinants of mental health and assessment identified by previous research, such as weather or seasonal indicators.
Findings: We find statistically significant effects of rater-biases. These effects are robust to a large array of controls.
Practical Implications: A back-of-the-envelope calculation reveals that the identified rater effects can translate to large changes in the waiting times for patients. Misspecified treatment allocations may lead to worsened symptoms and potentially fatal outcomes.
Originality / Value: Although a growing literature focuses on patient prioritization tools, many articles study these in synthetic contexts using “vignettes”. In comparison, our study adds external validity by considering real-life treatments in the field.
Research Limitations / Future Research: This study can be used as a starting point for deeper, causally focused studies.
Disclaimer: In accordance with publisher policies and our ethical obligations as researchers, we report that one of the authors is employed at a company that may be affected by the research reported in the enclosed paper. We have disclosed those interests fully.
Paper type: Empirical
49
Klahr, Hubert, et Andreas Schreiber. « Linking the Origin of Asteroids to Planetesimal Formation in the Solar Nebula ». Proceedings of the International Astronomical Union 10, S318 (août 2015) : 1–8. http://dx.doi.org/10.1017/s1743921315010406.
Texte intégralRésumé :
AbstractThe asteroids (more precisely: objects of the main asteroid belt) and Kuiper Belt objects (more precisely: objects of the cold classical Kuiper Belt) are leftovers of the building material for our earth and all other planets in our solar system from more than 4.5 billion years ago. At the time of their formation those were typically 100 km large objects. They were called planetesimals, built up from icy and dusty grains. In our current paradigm of planet formation it was turbulent flows and metastable flow patterns, like zonal flows and vortices, that concentrated mm to cm sized icy dust grains in sufficient numbers that a streaming instability followed by a gravitational collapse of these particle clump was triggered. The entire picture is sometimes referred to as gravoturbulent formation of planetesimals. What was missing until recently, was a physically motivated prediction on the typical sizes at which planetesimals should form via this process. Our numerical simulations in the past had only shown a correlation between numerical resolution and planetesimal size and thus no answer was possible (Johansen et al.2011). But with the lastest series of simulations on JUQUEEN (Stephan & Doctor 2015), covering all the length scales down to the physical size of actual planetesimals, we were able to obtain values for the turbulent particle diffusion as a function of the particle load in the gas. Thus, we have all necessary data at hand to feed a 'back of the envelope' calculation that predicts the size of planetesimals as result of a competition between gravitational concentration and turbulent diffusion. Using the diffusion values obtained in the numerical simulations it predicts planetesimal sizes on the order of 100 km, which suprisingly coincides with the measured data from both asteroids (Bottke et al.2005) as well from Kuiper Belt objects (Nesvorny et al.2011).
50
Geballe, T. H. « Why We Don't Have a Room-Temperature Superconductor—Yet : 1991 MRS Fall Von Hippel Award Address ». MRS Bulletin 17, no 7 (juillet 1992) : 70–77. http://dx.doi.org/10.1557/s0883769400041683.
Texte intégralRésumé :
I would like to raise a question of interest to many of us here today: “Why have we not been able to find a room-temperature superconductor?” I have a scenario for why not that can be illustrated by projecting ahead 98 years. It is 2089, the tercentenary of the French Revolution. The revolt against science that started building up in the last decade of the 20th century has reached a crescendo and a revolutionary tribunal has erected a huge guillotine. Following in the tradition of Lavoisier's trial and execution, the presidents of the Materials Research Society, the American Chemical Society, and the American Physical Society have been found to be enemies of the people and have been sentenced to be guillotined. The president of the Materials Research Society steps up. In his final words, he says: “I have no regrets. We've supplied you with the pole vaults which have made possible a new world's record above 30 feet, we've given you automobile bumpers that prevent damage in crashes at 60 miles per hour, and we've given you tennis rackets that are big enough to allow you to cover from center court to the alley without having to take a step.” With that, he bravely puts his head on the block. Down crashes the knife but inexplicably it stops just before it reaches his neck. According to the rules he steps down a free man. Then the American Chemical Society president steps up and says: “I don't have any regrets either. We have given you body centered cubic diamond that makes it possible to build indestructible houses, we have given you disposable diapers that are biodegradable in 30 seconds, and we've reseeded the stratosphere with ozone. We have done our job.” She courageously puts her head on the block, and the guillotine comes down. Again it stops short and she walks away, a free woman. Then the president of the American Physical Society says: “I don't have any regrets either. We've circled the equator with our newest SSC and have given you the Higgs boson, we've given you light that you can squeeze until it hurts, and we've discovered over 100 theoretical models which should lead to room-temperature superconductors. We haven't given you any real ones because there aren't any—we've tested all the possibilities. But, by the way, while we've been standing here, I've done a back-of-the-envelope calculation and I've found out wha's wrong with this guillotine. If you give me a screwdriver I can fix it.”