693 research outputs found
Discrimination in a Rank Order Contest: Evidence from the NFL Draft
This paper examines discrimination in the NFL draft. The NFL is a favorable empirical setting to examine the role of skin
color because franchise selectors are required to make rank-order judgements of players based on noisy signals of future
productivity. Since wages are tightly related to the rank-order of the draft for the first four years of a playerâs career, even
if discrimination plays only a marginal role in selection, there could be a large discriminatory impact. We observe racial
differences in drafting. However, much of the variation is explained by Black and White players selecting into different
playing positions. Conditional upon a large set of control variables, including athletic performance at a marque selection
event (the NFL combine), we do not find robust evidence of racial discrimination in NFL drafting between 2000 and 2018.
However, we do find some evidence that Black players are disadvantaged relative to White players in later rounds of the draf
ELT HARMONI: Image Slicer Preliminary Design
Harmoni is the ELT's first light visible and near-infrared integral field
spectrograph. It will provide four different spatial scales, ranging from
coarse spaxels of 60 x 30 mas best suited for seeing limited observations, to 4
mas spaxels that Nyquist sample the diffraction limited point spread function
of the ELT at near-infrared wavelengths. Each spaxel scale may be combined with
eleven spectral settings, that provide a range of spectral resolving powers
from R 3500 to R 20000 and instantaneous wavelength coverage spanning the 0.47
- 2.45 {\mu}m wavelength range of the instrument. The consortium consists of
several institutes in Europe under leadership of Oxford University. Harmoni is
starting its Final Design Phase after a Preliminary Design Phase in November,
2017. The CRAL has the responsibility of the Integral Field Unit design linking
the Preoptics to the 4 Spectrographs. It is composed of a field splitter
associated with a relay system and an image slicer that create from a
rectangular Field of View a very long (540mm) output slit for each
spectrograph. In this paper, the preliminary design and performances of Harmoni
Image Slicer will be presented including image quality, pupil distortion and
slit geometry. It has been designed by CRAL for Harmoni PDR in November, 2017.
Special emphases will be put on straylight analysis and slice diffraction. The
optimisation of the manufacturing and slit geometry will also be reported.Comment: 13 pages, 19 figures, 4 tables, Submitted to SPIE Astronomical
Telescopes and Instrumentatio
A classification system for global wave energy resources based on multivariate clustering
Better understanding of the global wave climate is required to inform wave energy device design and large-scale deployment. Spatial variability in the global wave climate is analysed here to provide a range of characteristic design wave climates. K-means clustering was used to split the global wave resource into 6 classes in a device agnostic, data-driven method using data from the ECMWF ERA5 reanalysis product. Classification using two sets of input data were considered: a simple set (based on significant wave height and peak wave period) and a comprehensive set including a wide range of relevant wave climate parameters. Both classifications gave resource classes with similar characteristics; 55% of tested locations were assigned to the same class. Two classes were low energy, found in enclosed seas and sheltered regions. Two classes were moderate wave energy classes; one swell dominated and the other in areas with wave action often generated by more local storms. Of the two higher energy classes; one was more often found in the northern hemisphere and the other, most energetic, predominantly on the tips of continents in the southern hemisphere. These classes match existing regional understanding of resource. Consideration of publicly available device power matrices showed good performance was primarily realised for the two highest energy resource classes (25â30% of potential deployment locations); it is suggested that effort should focus on optimising devices for additional resource classes. The authors hypothesise that the low-risk, low variability, swell dominated moderate wave energy class would be most suitable for future exploitation
LOKASI ALOKASI BAHAN BAKU DAN MODA TRANSPORTASI PADA JARINGAN RANTAI PASOK MINYAK KAYU PUTIH DI KPH SURAKARTA
Tujuan dari penelitian ini adalah untuk mengidentifikasi kondisi rantai pasok kayu putih di wilayah KPH Surakarta, melakukan analisis kelayakan pembangunan tempat penyulingan daun kayu putih, dan membuat model lokasi alokasi berdasarkan total biaya minimal untuk rantai pasok kayu putih di KPH Surakarta. Identifikasi rantai pasok dilakukan dengan analisis rantai pasok menggunakan metode APO (Asian Productivity Organization). Analisis kelayakan investasi dilakukan dengan melakukan perhitungan Net Present Value, Break Event Point, Rate on Investment, Benefit Cost Ratio, dan Internal Rate of Return. Untuk model matematis yang dibuat digunakan model Mixed Integer Linear Programming dengan mempertimbangkan jumlah armada dan kapasitas moda transportasi yang dimiliki. Dari identifikasi rantai pasok dapat diketahui permasalahan yang menyebabkan rendahnya supply dari supplier sehingga demand minyak kayu putih tidak dapat dipenuhi. Dari analisis investasi yang dilakukan dipilih alternatif yang merupakan alternatif terbaik yaitu alternatif 2. Model matematis yang dibuat memperlihatkan besarnya penghematan yang dapat dilakukan perusahaan dengan penentuan alokasi yang tepat serta penambahan distillery baru. Dari hasil juga dapat ditentukan alokasi bahan baku pada tiap-tiap distillery dan KBM
Wave resource variability: Impacts on wave power supply over regional to international scales
The intermittent, irregular and variable nature of the wave energy resource has implications for the supply of wave-generated electricity into the grid; intermittency of renewable power may lead to frequency and voltage fluctuations in the transmission and distribution networks. This study analyses the wave resource over different spatial scales to investigate the potential impacts of the resource variability on the grid supply. It is found that the deployment of multiple wave energy sites results in a reduction in step changes in power, leading to an overall smoothing of the wave-generated electrical power
Building future scenarios using cognitive mapping
A participatory approach for developing future scenarios through cognitive maps as a visual representation of mental models is presented. Applying long-term future visioning techniques in a workshop setting has traditionally been a significant challenge for construction industry practitioners with a predominantly short-term, project-based approach to day-to-day operational responsibilities. Six future scenario cognitive maps are presented to illustrate the process. The maps were digitised from A1-sized papers using Decision Explorer software. Several key characteristics of the resulting cognitive maps and lessons learnt for the organisation of industry-based workshops are discussed. The main benefits are derived from the interaction between participants during the mapping process whereby future issues and their interconnectivities are discussed. Limitations of the findings and further work are presented
Exoplanet atmospheres Characterization Observatory payload short-wave infrared channel: EChO SWiR
EChO (Exoplanet atmospheres Characterization Observatory), a proposal for exoplanets exploration space mission, is considered the next step for planetary atmospheres characterization. It would be a dedicated observatory to uncover a large selected sample of planets spanning a wide range of masses (from gas giants to super-Earths) and orbital temperatures (from hot to habitable). All targets move around stars of spectral types F, G, K, and M. EChO would provide an unprecedented view of the atmospheres of planets in the solar neighbourhood. The consortium formed by various institutions of different countries proposed as ESA M3 an integrated spectrometer payload for EChO covering the wavelength interval 0.4 to 16 ”m. This instrument is subdivided into 4 channels: a visible channel, which includes a fine guidance system (FGS) and a VIS spectrometer, a near infrared channel (SWiR), a middle infrared channel (MWiR), and a long wave infrared module (LWiR). In addition, it contains a common set of optics spectrally dividing the wavelength coverage and injecting the combined light of parent stars and their exoplanets into the different channels. The proposed payload meets all of the key performance requirements detailed in the ESA call for proposals as well as all scientific goals. EChO payload is based on different spectrometers covering the spectral range mentioned above. Among them, SWiR spectrometer would work from 2.45 microns to 5.45 microns. In this paper, the optical and mechanical designs of the SWiR channel instrument are reported on
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TOI-431/HIP 26013: A super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet
We present the bright (Vmag = 9.12), multiplanet system TOI-431, characterized with photometry and radial velocities (RVs). We estimate the stellar rotation period to be 30.5 ± 0.7 d using archival photometry and RVs. Transiting Exoplanet Survey Satellite (TESS) objects of Interest (TOI)-431 b is a super-Earth with a period of 0.49 d, a radius of 1.28 ± 0.04 R, a mass of 3.07 ± 0.35 M, and a density of 8.0 ± 1.0 g cm-3; TOI-431 d is a sub-Neptune with a period of 12.46 d, a radius of 3.29 ± 0.09 R, a mass of 9.90+1.53-1.49 M, and a density of 1.36 ± 0.25 g cm-3. We find a third planet, TOI-431 c, in the High Accuracy Radial velocity Planet Searcher RV data, but it is not seen to transit in the TESS light curves. It has an Msin i of 2.83+0.41-0.34 M, and a period of 4.85 d. TOI-431 d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterization, while the super-Earth TOI-431 b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431 b is a prime TESS discovery for the study of rocky planet phase curves.Fil: Osborn, Ares. University of Warwick; Reino UnidoFil: Armstrong, David J. University of Warwick; Reino UnidoFil: Cale, Bryson. George Mason University; Estados UnidosFil: Brahm, Rafael. Universidad Adolfo Ibañez; Chile. Instituto de AstrofĂsica; ChileFil: Wittenmyer, Robert A. University Of Southern Queensland; AustraliaFil: Dai, Fei. Division Of Geological And Planetary Sciences; Estados UnidosFil: Crossfield, Ian J. M. University of Kansas; Estados UnidosFil: Bryant, Edward M. University of Warwick; Reino UnidoFil: Adibekyan, Vardan. Universidad de Porto; PortugalFil: Cloutier, Ryan. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Collins, Karen A. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Delgado Mena, E.. Universidad de Porto; PortugalFil: Fridlund, Malcolm. Leiden University; PaĂses Bajos. Chalmers University of Technology; SueciaFil: Hellier, Coel. Keele University; Reino UnidoFil: Howell, Steve B. NASA Ames Research Center; Estados UnidosFil: King, George W. University of Warwick; Reino UnidoFil: Lillo Box, Jorge. Consejo Superior de Investigaciones CientĂficas. Centro de AstrobiologĂa; EspañaFil: Otegi, Jon. Universidad de Ginebra; Suiza. Universitat Zurich; SuizaFil: Sousa, S.. Universidad de Porto; PortugalFil: Stassun, Keivan G. Vanderbilt University; Estados UnidosFil: Matthews, Elisabeth C. Universidad de Ginebra; Suiza. Massachusetts Institute of Technology; Estados UnidosFil: Ziegler, Carl. University of Toronto; CanadĂĄFil: Ricker, George. Massachusetts Institute of Technology; Estados UnidosFil: Vanderspek, Roland. Massachusetts Institute of Technology; Estados UnidosFil: Latham, David W. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Seager, S.. Massachusetts Institute of Technology; Estados UnidosFil: Winn, Joshua N.. University of Princeton; Estados UnidosFil: Jenkins, Jon M. NASA Ames Research Center; Estados UnidosFil: Acton, Jack S. University of Leicester; Reino UnidoFil: Addison, Brett C. University Of Southern Queensland; AustraliaFil: Diaz, Rodrigo Fernando. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de Ciencias FĂsicas. - Universidad Nacional de San MartĂn. Instituto de Ciencias FĂsicas; Argentin
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