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

Cooling of Quark Stars in the Color Superconductive Phase: Effect of Photons from Glueball decay

The cooling history of a quark star in the color superconductive phase is investigated. Here we specifically focus on the 2-flavour color (2SC) phase where novel process of photon generation via glueball (GLB) decay have been already investigated (Ouyed & Sannino 2001). The picture we present here can in principle be generalized to quark stars entering a superconductive phase where similar photon generation mechanisms are at play. As much as 10^{45}-10^{47} erg of energy is provided by the GLB decay in the 2SC phase. The generated photons slowly diffuse out of the quark star keeping it hot and radiating as a black-body (with possibly a Wien spectrum in gamma-rays) for millions of years. We discuss hot radio-quiet isolated neutron stars in our picture (such as RX J185635-3754 and RX J0720.4-3125) and argue that their nearly blackbody spectra (with a few broad features) and their remarkably tiny hydrogen atmosphere are indications that these might be quark stars in the color superconductive phase where some sort of photon generation mechanism (reminiscent of the GLB decay) has taken place. Fits to observed data of cooling compact stars favor models with superconductive gaps of Delta_2SC = 15-35 MeV and densities rho_2SC=(2.5-3.0)rho_N (rho_N being the nuclear matter saturation density) for quark matter in the 2SC phase. If correct, our model combined with more observations of isolated compact stars could provide vital information to studies of quark matter and its exotic phases.Comment: 7 journal pages, 4 figures, accepted for publication in MNRAS (more discussions on photon cooling versus neutrino cooling before and after pairing of quarks

Evaluating the Efficacy of a Novel Phytase Source

A total of 350 nursery pigs (PIC 1050 barrows, initially 33.2 lb and 49 d of age) were used in a 21-d study to determine the aP release curve for a novel phytase product (Microtech 5,000, VTR Bio-tech Co., Guangdong, China). Pigs were randomly allotted to pens at arrival to the facility, and on d 0 of the trial pens were allotted to 1 of 7 treatments in a randomized complete block design. There were 5 pigs per pen and 10 pens per treatment. Pigs were fed corn-soybean meal-based diets formulated to 1.25% SID lysine. A single batch of the basal diet (0.12% aP) was manufactured and subsequently divided and used as the major ingredient in experimental diet manufacturing. Experimental diets were formulated to contain increasing available P supplied by either an inorganic source (0.12%, 0.18%, and 0.24% aP from monocalcium P) or from increased phytase (250, 500, 750, 1000 FTU/kg). Diets were analyzed for phytase using the AOAC method, and analyzed concentrations were lower than formulated. Diets formulated to contain 250, 500, 750 and 1000 FTU/kg had analyzed concentrations of 155, 335, 465, and 780 FTU/kg, respectively. On d 21, one pig per pen was euthanized and fibulas were collected to determine bone ash weight and percentage bone ash. From d 0 to 21, increasing P from inorganic P or increasing phytase resulted in increased (linear, P \u3c 0.01) ADG, improved (quadratic, P \u3c 0.02) F/G, and heavier (linear P \u3c 0.01) ending BW. Bone ash weight and percentage bone ash were increased (linear, P \u3c 0.01) with increasing inorganic P and increasing phytase. Response criteria, which remained in the linear portion of the quadratic phytase curve (ADG, bone ash weight, and percentage bone ash), were used to calculate aP release curves. When analyzed phytase values and percentage bone ash are used as the response variable, aP release percentage for up to 780 FTU/kg of Microtech 5,000 phytase can be predicted by the equation (y = 0.000002766761x - 0.000000002225x2 - 0.000201841391), where x is the phytase concentration in the diet (FTU/kg)

Vitamin and Trace Minerals: A Survey of Current Feeding Regimens

Swine producers and nutritionists representing production systems across the United States were surveyed about added vitamin and trace mineral concentrations in swine diets used from March to August of 2014. Respondents were asked to provide the vitamin and trace mineral premix specifications and inclusion rates to calculate complete diet added vitamin and trace mineral concentrations. Weight ranges associated with feeding phases also were collected. In total, 18 production systems representing approximately 2.3 million sows (~40% of the U.S. sow herd) participated in the survey. Data were compiled into relatively consistent weight ranges across all participating producers. There were three nursery phases (Phase 1, weaning to 15 lb; Phase 2, 15 to 25 lb; and Phase 3, 25 to 50 lb), four finishing phases (early, 50 to 120 lb; mid, 120 to 220 lb; late, 220 lb to Market; and late with ractopamine HCl, 220 lb to Market), and four breeding herd diets (gilt development, gestation, lactation, and boar). Results were compiled and pooled to determine descriptive statistics on the supplementation rates. Descriptive statistics used included: average, weighted average (determined by size of operation), standard deviation, median, minimum, maximum, 25th percentile (lowest quartile), and 75th percentile (highest quartile). Within each dietary phase, the nutrients of interest were: vitamins A, D, E, and K; thiamin; riboflavin; niacin; pantothenic acid; pyridoxine; biotin; folic acid; vitamin B12; choline; betaine; vitamin C; carnitine; Cu; I; Fe; Mn; Se; Zn; Co; and Cr. Average supplementation rates for vitamins and trace minerals within each phase of production were compared to the requirement estimates reported in the NRC (2012). Results indicated tremendous variation in supplementation rates, but most vitamins and trace minerals were included at levels above the requirement estimates reported in the NRC (2012). Along with vitamin and trace mineral supplementation rates, respondents were asked about sources of specific nutrients used in premixes. The most distinguishable differences among sources within this survey were associated with the vitamin D3 from a cross-linked vitamin A/D3 beadlet, use of natural (d-α-tocopherol) vitamin E, and the use of organic trace minerals (Cu, Mn, Se, and Zn). Ultimately, evaluating current supplementation practices can be used to develop future experimental designs to test vitamin and trace mineral supplementation practices

Using Meta-analyses to Generate Alternative Prediction Equations for the Space Requirements of Finishing Pigs

Data from existing literature examining the influence of floor space allowance on the growth of finishing pigs were used to develop prediction equations for ADG, ADFI, and G:F. Two sets of databases were used. The first database included information from studies examining the influence of floor space allowance. The second database included the aforementioned literature, along with papers examining the impact of floor space after pigs were removed from the pen (topping). The first database included 27, 25, and 25 papers for ADG, ADFI, and G:F, respectively. The second database included 30, 28, and 28 papers for ADG, ADFI, and G:F, respectively. The predictor variables tested were floor space (m2/pig), k (floor space, m2/final BW, kg0.67), initial BW (kg), final BW (kg), feeder space (pigs per feeder hole), water space (pigs per waterer), group size (pigs per pen), gender, floor type, and study length (d). A mixed linear model approach was used for model development, and floor space treatments within each experiment were the experimental units. Evaluations of models with significant terms were conducted using the Bayesian Information Criterion (BIC). The optimum equations to predict finishing ADG, ADFI, and G:F for the first database were: ADG, g =395.57+(15,727 × k)-(221,705 × k2)-(3.6478 × Initial BW, kg)+(2.209 × Final BW, kg)+(67.6294 × k × Initial BW, kg) ADFI, g =802.07+(20,121× k)-(301,210 × k2)-(1.5985 × Initial BW, kg)+(11.8907 × Final BW, kg )+(159.79 × k × Initial BW, kg) G:F =Predicted ADG/Predicted ADFI The optimum equations to predict ADG, ADFI, and G:F for the second database were: ADG, g =337.57+(16,468 × k)-(237,350 × k2)-(3.1209 × Initial BW, kg)+(2.569 × Final BW, kg)+(71.6918 × k × Initial BW, kg) ADFI, g = 833.41+(24,785 × k)-(388,998 × k2)-(3.0027 × Initial BW, kg)+(11.246 × Final BW, kg)+(187.61 × k × Initial BW, kg) G:F =Predicted ADG/Predicted ADFI All multi-term models reduced the BIC values compared to individual term models. Data from 3 separate experiments examining the effects of floor space allowance on growth performance were used to evaluate the accuracy of the prediction equations herein and also previously developed prediction equations (Kornegay and Notter, 1984; Powell et al., 1993; and Gonyou et al., 2006). Predicted values from equations reported herein improved model evaluation statistics compared to Kornegay and Notter (1984), and Powell (1993), and were comparable to predicted values by Gonyou et al. (2006), with improved root mean square error calculations that suggest more accurate predictions of growth rate. Between the equations developed from the databases, those from the second database more accurately predict growth performance at heavier BW ranges as well as the growth performance of finishing pigs remaining in a pen after pigs are removed

Evaluating the Effects of Maternal Vitamin D Supplementation on the Subsequent Growth Performance and Carcass Characteristics of a Subsample Population of Growing Pigs

A subsample of 448 growing pigs (PIC 327 × 1050), or approximately 50% of pigs weaned from sows fed varying dietary vitamin D regimens, were used in a split-plot design to determine the influence of maternal and nursery vitamin D regimens on growth performance. Sows were previously administered diets containing vitamin D as either: 1) low vitamin D3 (363 IU/lb); 2) medium vitamin D3 (907 IU/lb); 3) high vitamin D3 (4,354 IU/lb); or 4) 23 μg 25(OH)D3/lb (Hy-D, DSM Nutritional Products Inc, Parsippany, NJ) as described by Flohr et al. (20153) throughout gestation and lactation. A total of 52 total litters from 2 consecutive weaning groups were represented in the subsample population for growth performance. Once weaned, pigs were allotted to pens in the nursery based on previously administered maternal vitamin D regimens, then pens were randomly assigned to 1 of 2 nursery vitamin D regimens (907 IU of vitamin D3/lb, or 23 μg 25(OH)D3/lb). Pigs remained on nursery vitamin D regimens for 35 d, then they were provided common growing and finishing diets until market. One pig per pen was bled at weaning and on d 17, 35, and 70 post-weaning to determine growing pig serum vitamin metabolites. At weaning, pig BW was increased (quadratic, P = 0.001) with increased maternal vitamin D3 supplementation. This was because pigs from sows fed the medium concentration of vitamin D3 were heavier at weaning compared to pigs from sows fed the low or high concentration of vitamin D3. Overall from d 0 to 35 in the nursery, pigs from sows fed increasing vitamin D3 had increased (quadratic, P \u3c 0.003) ADG and ADFI, but F/G was similar regardless of maternal Vitamin D regimen. Pigs from sows fed the low concentration of vitamin D3 had poorer (P \u3c 0.002) ADG and final nursery BW compared to those from sows fed 25(OH)D3. Throughout finishing (d 35 post-weaning until market), ADG was increased (quadratic, P = 0.005) and ADFI tended to increase (quadratic, P = 0.055) with increasing maternal vitamin D3 supplementation because pigs from sows fed the medium concentration of vitamin D3 had greater ADG and numerically greater ADFI compared to pigs from sows fed the low or high concentration of vitamin D3. Average daily gain of pigs from sows fed the low concentration of vitamin D3 was lower (P \u3c 0.004) compared to those from sows fed 25(OH)D3. Carcass data were also collected from 734 pigs (approximately 65% of pigs weaned from sows administered vitamin D regimens) from 3 out of the 4 weaning groups used for the experiment. At marketing, live BW and HCW were heavier (P \u3c 0.030) for pigs from sows fed 25(OH)D3 compared to pigs from sows fed the high concentration of vitamin D3. Also, percentage carcass yield increased (quadratic, P = 0.003) with increasing maternal vitamin D3 supplementation. Loin depth (linear P = 0.047) and BF (quadratic, P = 0.031) were both decreased with increasing vitamin D3 supplementation. Overall, it appears that vitamin D3 and 25(OH)D3, whether through maternal supplementation or through the diet, are useful sources of vitamin D to increase serum 25(OH)D3 concentrations in growing pigs. Additionally, 25(OH)D3 (in the nursery diet) can increase serum 25(OH)D3 of nursery pigs more than feeding the same international unit equivalency of vitamin D3. Pigs from sows fed the medium concentration of vitamin D3 performed better after weaning compared to pigs from sows fed the low or high concentrations of vitamin D3; however, this difference may have been confounded with the variance in weaning weight associated with the subsample population used for the growth portion of the study. Also, it is perceived that pigs from sows fed 25(OH)D3 had increased live weight and HCW compared to pigs from sows fed the high concentration of vitamin D3

Evaluating the Impact of Maternal Vitamin D Supplementation on Sow Performance, Serum Vitamin Metabolites, Neonatal Muscle and Bone Characteristics, and Subsequent Pre-weaning Pig Performance

A total of 56 gestating sows (PIC 1050; 35-d post-insemination) were used in a 30-d trial to determine the serum 25(OH)D3 response to increasing concentrations of vitamins D3. At initiation, sows were randomly allotted to 1 of 7 dietary vitamin D3 treatments (91, 363, 726, 1,451, 2,903, 5,806, or 11,612 IU of vitamin D3/lb of complete diet) with 8 sows per treatment. All sows were fed 5.5 lb daily at 0800. Increasing vitamin D3 increased (quadratic; P \u3c 0.001) serum 25(OH)D3 with the response depicted by the following prediction equation: Serum 25(OH)D3, ng/mL = 35.1746 + (0.002353 × dietary vitamin D3, IU/d) - (0.0000000156 × dietary vitamin D3, IU/d2) In Exp. 2, 112 sows and their litters were used to determine the effects of supplemented vitamin D on sow performance, subsequent pre-weaning pig performance, neonatal pig bone and muscle characteristics, and serum vitamin metabolites. Sows were allotted to 1 of 4 dietary regimens: 1) low vitamin D3 (363 IU/lb); 2) medium vitamin D3 (907 IU/lb); 3) high vitamin D3 (4,354 IU/lb); or 4) 23 μg 25(OH)D3/lb (Hy-D, DSM Nutritional Products Inc, Parsippany, NJ), which were fed throughout gestation and lactation. There were 25 to 27 sows per treatment. Overall, increasing maternal vitamin D3 increased (linear, P = 0.001) serum 25 (OH)D3 of sows on d 100 of gestation, at farrowing, and at weaning. Also increasing vitamin D3 in diets fed to sows increased piglet serum 25(OH)D3 at birth (linear, P = 0.001) and weaning (quadratic, P = 0.033). Sows fed 25(OH)D3 had greater (P \u3c 0.001) serum 25(OH)D3 concentrations on d 100 of gestation, at farrowing, and at weaning compared to sows fed the low or medium concentration of vitamin D3; however, they were reduced (P \u3c 0.004) compared to the serum 25(OH)D3 concentrations of sows fed the high concentration of vitamin D3 on the same collection days. Piglets from sows fed 25(OH)D3 had greater serum 25(OH)D3 compared to piglets from sows fed the low and medium concentration of vitamin D3; however, at weaning, serum 25(OH)D3 concentrations were only greater compared to the low concentration of vitamin D3. Also, piglets from sows fed the high concentration of vitamin D had greater (P = 0.011) serum 25(OH)D3 concentration at birth and at weaning, compared to piglets from sows fed 25(OH)D3. Maternal performance, litter characteristics, neonatal bone ash content, and neonatal muscle fiber characteristics were largely unaffected by the maternal vitamin D regimen. Overall, vitamin D3 and 25(OH)D3 both appear to be useful at increasing serum 25(OH) D3 concentrations, but more vitamin D3 (on an IU basis) is needed to achieve similar serum 25(OH)D3 responses compared to feeding 25(OH)D3. Interestingly, sows fed 25(OH)D3 in lactation had less vitamin D transport to the pig than sows fed medium and high concentrations of vitamin D3 suggesting that vitamin D3 is still a more useful metabolite for milk transfer of the vitamin. Due to the lack of impact of maternal vitamin D regimen on sow or pre-weaned pig performance, and neonatal muscle characteristics, more research examining the impact of vitamin D on immune function and novel biological processes is needed to assess the value of vitamin D supplementation strategies in pigs

Application of Alternative Floor Space Prediction Equations using Microsoft Excel®

The following information is related to the use of a spreadsheet tool designed to estimate the growth rate of finishing pigs provided varying floor space allowances. The spreadsheet is broken into four sections: 1) the adjustment observation section, 2) the estimate input section, 3) the database range information, and 4) the predicted performance output. Sections 1 and 2 allow users to input information to adjust the prediction equations to specific herd growth rates as well as information needed to calculate the growth rate estimates for different floor space allowances. This tool allows producers to utilize the prediction equations without having to convert standard to metric units and provides a simple output that is easy to evaluate and use as compared to the more complex prediction equations themselves. Three examples are included to show users the possible value of the spreadsheet tool. It is important for users to understand the potential pitfalls associated with inputting information into the spreadsheet and formatting “flags” that warn users of potential problems in the input information

Foreword and Supplemental Information, Swine Day

It is with great pleasure that we present the 2016 Swine Industry Day Report of Progress. This report contains updates and summaries of applied and basic research conducted at Kansas State University during the past year. We hope that the information will be of benefit as we attempt to meet the needs of the Kansas swine industry