Article submitted to journal

rspa.royalsocietypublishing.or

Constant net-time headway as key mechanism behind pedestrian flow dynamics

We show that keeping a constant lower limit on the net-time headway is the key mechanism behind the dynamics of pedestrian streams. There is a large variety in flow and speed as functions of density for empirical data of pedestrian streams, obtained from studies in different countries. The net-time headway however, stays approximately constant over all these different data sets. By using this fact, we demonstrate how the underlying dynamics of pedestrian crowds, naturally follows from local interactions. This means that there is no need to come up with an arbitrary fit function (with arbitrary fit parameters) as has traditionally been done. Further, by using not only the average density values, but the variance as well, we show how the recently reported stop-and-go waves [Helbing et al., Physical Review E, 75, 046109] emerge when local density variations take values exceeding a certain maximum global (average) density, which makes pedestrians stop.Comment: 7 pages, 7 figure

Fairness-Aware Ranking in Search & Recommendation Systems with Application to LinkedIn Talent Search

We present a framework for quantifying and mitigating algorithmic bias in mechanisms designed for ranking individuals, typically used as part of web-scale search and recommendation systems. We first propose complementary measures to quantify bias with respect to protected attributes such as gender and age. We then present algorithms for computing fairness-aware re-ranking of results. For a given search or recommendation task, our algorithms seek to achieve a desired distribution of top ranked results with respect to one or more protected attributes. We show that such a framework can be tailored to achieve fairness criteria such as equality of opportunity and demographic parity depending on the choice of the desired distribution. We evaluate the proposed algorithms via extensive simulations over different parameter choices, and study the effect of fairness-aware ranking on both bias and utility measures. We finally present the online A/B testing results from applying our framework towards representative ranking in LinkedIn Talent Search, and discuss the lessons learned in practice. Our approach resulted in tremendous improvement in the fairness metrics (nearly three fold increase in the number of search queries with representative results) without affecting the business metrics, which paved the way for deployment to 100% of LinkedIn Recruiter users worldwide. Ours is the first large-scale deployed framework for ensuring fairness in the hiring domain, with the potential positive impact for more than 630M LinkedIn members.Comment: This paper has been accepted for publication at ACM KDD 201

Determining the Influence of KemTRACE Cr and/or Micro-Aid on Growth Performance and Carcass Composition of Pigs Housed in a Commercial Environment

A study was conducted to determine the interactive effects of chromium propionate (KemTRACE Cr; Kemin Industries Inc., Des Moines, IA) and Micro-Aid (Yucca schidigera-based product; Distributors Processing Inc., Porterville, CA) on growth performance and carcass composition of finishing pigs housed in a commercial environment. There were a total of 1,188 pigs (PIC 337 × 1050; initial BW = 60.3 lb) with 27 pigs/ pen and 11 pens/treatment. Pigs were split by gender upon arrival at the facility, with 5 blocks of each gender and a final mixed sex gender block. Gender blocks were randomly allotted to groups of 4 pen locations within the barn. Diets were corn-soybean meal-dried distillers grains with solubles-based and were fed in 5 phases. All nutrients were formulated to meet or exceed NRC (2012) requirement estimates. Treatments were arranged as a 2 × 2 factorial with main effects of Cr (0 vs 200 ppb) or Micro-Aid (0 vs 62.5 ppm). There were no Cr × Micro-Aid interactions observed for growth or carcass measurements. Overall, ADG and F/G were not influenced by treatment. Adding Cr alone increased (P = 0.048) ADFI, and inclusion of Micro-Aid resulted in a marginally significant increase (P = 0.076) in ADFI. For carcass characteristics, HCW, loin depth, and percentage carcass yield were not influenced by treatment. Backfat depth tended to increase (P = 0.055) and lean percentage was decreased (P = 0.014) when Cr was added to diets. In summary, no synergistic effects were observed from feeding Cr and Micro-Aid in diets fed to finishing pigs housed in a commercial environment. Only marginal differences were observed from adding Cr or Micro-Aid with increased ADFI observed from feeding either. Finally, diets containing added Cr tended to be associated with carcasses having more backfat and less lean suggesting the increased ADFI was not utilized for increased muscle deposition

Influence of Chromium Dose and Feeding Regimen on Growth Performance and Carcass Composition of Pigs Housed in a Commercial Environment

A study was conducted to determine the effects of increasing chromium propionate (KemTRACE Cr; Kemin Industries Inc., Des Moines, IA) and feeding regimen on growth performance and carcass characteristics of finishing pigs housed in a commercial environment. There were a total of 1,206 pigs (PIC 337 × 1050; initial BW = 63.2 lb) with 27 pigs/pen and 9 pens/treatment. Pigs were split by gender upon arrival at the facility, with 4 blocks of each gender and a final mixed gender block. Gender blocks were randomly allotted to groups of 5 pen locations within the barn. Diets were corn-soybean meal-dried distillers grains with solubles-based and were fed in a 5-phase feeding program. Treatments were arranged as a 2 × 2 + 1 factorial with a control diet containing no added Cr, or diets containing either 100 or 200 ppb of Cr fed during the grower (dietary Phases 1 and 2; 63 to 138 lb BW) and/or finisher (dietary Phases 3, 4, and 5; 138 to 307 lb BW) periods. For growth performance, there was no effect of changing Cr supplementation between the growing and finishing periods. Therefore, only linear and quadratic effects of increasing Cr within growth period were considered using all treatments, as well as linear and quadratic effects of the 3 treatments fed increasing Cr for the full duration of the study. Increasing Cr during the grower period decreased (quadratic, P \u3c 0.001) ADG and worsened F/G. During the finisher period, increasing Cr tended (quadratic, P = 0.061) to improve F/G, with the best F/G observed in pigs fed 100 ppb. Overall, increasing Cr had no impact on ADG or ADFI; however, F/G was optimized (quadratic, P = 0.018) when pigs were fed 100 ppb of added Cr. Carcass characteristics were not influenced by added Cr level or Cr feeding regimen. In summary, increasing dietary Cr supplementation elicited minor changes in growth performance with the best F/G observed with 100 ppb of added Cr

Effects of different zinc oxide sources on weanling pig growth performance

A total of 192 pigs (initially 13.61b and 18 d of age) were used in a 27-d growth assay to determine the effects of different ZnO sources on weanling pig growth performance. The four experimental treatments consisted of a control diet or three diets containing Zn from ZnO from one of three different sources. For the entire trial, no differences occurred in growth performance of pigs fed the different ZnO sources; however, all sources increased ADG and ADFI compared to pigs fed the control diet. Economics and ingredient availability should dictate which ZnO source to use in weanling pig diets to promote growth.; Swine Day, Manhattan, KS, November 18, 199

Effects of Standardized Ileal Digestible Lysine Content in Low Crude Protein Diets on Finishing Pig Performance and Economics from 230 to 280 lb

The objective of this study was to estimate the nutritional requirement of standardized ileal digestible (SID) Lys on growth performance and economics of 230- to 280-lb finishing pigs housed in a commercial environment and fed diets not containing ractopamine HCl. A total of 1,101 gilts (PIC L327 × 1050, initially 233.4 lb BW) were used in a 28-d growth trial. Pens were blocked by BW and were randomly assigned to diets with 27 pigs per pen and 7 pens per treatment in a randomized complete block design. Diets were corn and soybean meal-based and fed in meal form, with dietary treatments consisting of: 0.52, 0.58, 0.64, 0.70, 0.76, or 0.82% SID lysine. Increasing SID Lys increased (linear, P \u3c 0.05) ADG and final BW, resulting in pigs fed 0.82% SID Lys having the greatest final BW. There was no difference in ADFI among pigs fed different SID Lys levels. Feed efficiency was improved (linear, P \u3c 0.05) with increasing SID Lys. In addition, there was an improvement (linear, P \u3c 0.05) in caloric efficiency on both a ME and NE basis with increasing SID Lys. Feed cost per pig increased (linear, P \u3c 0.05) as SID lysine level increased. However, there was no difference in feed cost/lb gain. Total revenue per pig increased (linear, P \u3c 0.05) while income over feed cost (IOFC) tended to increase (linear, P \u3c 0.07) as SID lysine level increased. Quadratic polynomial and broken-line linear models to maximize ADG resulted in similar fit and predicted the SID Lys level required to maximize ADG to be greater than 0.82 and at 0.685% SID Lys, QP vs. BLL, respectively. Using the QP model, 95% of the maximum growth was predicted to be at 0.675% SID Lys. The best F/G was achieved at greater than 0.82 and at 0.648% SID Lys for QP vs. BLL, respectively, with 95% of lowest F/G predicted at 0.638% SID Lys using the QP model. IOFC was maximized by the QP and BLL model at 0.754 and 0.640% SID Lys, respectively. In summary, the SID lysine requirement for optimal ADG, F/G, and IOFC of finishing pigs is at least 0.64% SID Lys

The Acclaim Programme in the South Atlantic and Southern Oceans

The ACCLAIM sea level network consists of six coastal tide gauge sites and approximately a dozen bottom pressure stations in the South Atlantic and Southern Oceans. Since 1985, an extensive dataset of regional sea level and bottom pressure measurements has been acquired. This dataset is being employed at POL in a number of scientific analyses and is available to any interested research worker through the World Ocean Circulation Experiment. In this paper, a review is given of the development and status of the ACCLAIM network and the technology installed at each site. Plans are presented for developments over the next 1-2 years