Unveiling Palomar 2: The Most Obscure Globular Cluster in the Outer Halo

We present the first color-magnitude study for Palomar 2, a distant and heavily obscured globular cluster near the Galactic anticenter. Our (V,V-I) color-magnitude diagram (CMD), obtained with the UH8K camera at the CFHT, reaches V(lim) = 24 and clearly shows the principal sequences of the cluster, though with substantial overall foreground absorption and differential reddening. The CMD morphology shows a well populated red horizontal branch with a sparser extension to the blue, similar to clusters such as NGC 1261, 1851, or 6229 with metallicities near [Fe/H] = -1.3$. From an average of several indicators, we estimate the foreground reddening at E(B-V) = 1.24 +- 0.07 and obtain a true distance modulus (m-M)_0 = 17.1 +- 0.3$, placing it about 34 kpc from the Galactic center. We use starcounts of the bright stars to measure the core radius, half-mass radius, and central concentration of the cluster. Its integrated luminosity is M_V = -7.9, making it clearly brighter and more massive than most other clusters in the outer halo.Comment: 25 pages, aastex, with 8 postscript figures; accepted for publication in AJ, September 1997. Also available by e-mail from [email protected]. Please consult Harris directly for (big) postscript files of Figures 1a,b (the images of the cluster

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

Long-term and recent changes in sea level in the Falkland Islands

Mean sea level measurements made at Port Louis in the Falkland Islands in 1981-2, 1984 and 2009, together with values from the nearby permanent tide gauge at Port Stanley, have been compared to measurements made at Port Louis in 1842 by James Clark Ross. The long-term rate of change of sea level is estimated to have been +0.75 ± 0.35 mm/year between 1842 and the early 1980s, after correction for air pressure effects and for vertical land movement due to Glacial Isostatic Adjustment (GIA). The 2009 Port Louis data set is of particular importance due to the availability of simultaneous information from Port Stanley. The data set has been employed in two ways, by providing a short recent estimate of mean sea level itself, and by enabling the effective combination of measurements at the two sites. The rate of sea level rise observed since 1992, when the modern Stanley gauge was installed, has been larger at 2.51 ± 0.58 mm/year, after correction for air pressure and GIA. This rate compares to a value of 2.79 ± 0.42 mm/year obtained from satellite altimetry in the region over the same period. Such a relatively recent acceleration in the rate of sea level rise is consistent with findings from other locations in the southern hemisphere and globall

Correction to "Long-term and recent changes in sea level in the Falkland Islands"

In the paper “Long-term and recent changes in sea level in the Falkland Islands” by P. L. Woodworth et al. (Journal of Geophysical Research, 115, C09025, doi:10.1029/2010JC006113, 2010), in paragraph 47 we adopted a value of −0.52 mm/yr for the estimated rate of present-day sea level change in the Falkland Islands due to glacial isostatic adjustment (GIA). This value was used to remove the contributions of GIA to our measurements of historical and recent rates of sea level change. However, it was based on a misreading of the data file of Peltier [2004] on the Permanent Service for Mean Sea Level Web site (http://www.psmsl.org/train_and_info/geo_signals/gia/peltier). More reasonable values to apply to the observed changes since the mid-nineteenth century and in recent years would be −0.69 and −0.61 mm/yr respectively. Consequently, the long-term rate of sea level change between 1842 and the early 1980s, after correction for air pressure effects and for GIA, reported as +0.75 ± 0.35 mm/yr in paragraphs 1, 47, 55, and 61 should be +0.92 ± 0.35 mm/yr, the corresponding rate between 1842 and the midpoint of recent data of 1.06 ± 0.22 mm/yr in paragraphs 48 and 55 should be 1.23 ± 0.22 mm/yr, and the corresponding rate since 1992 reported as 2.51 ± 0.58 mm/yr in paragraphs 1 and 52 becomes 2.60 ± 0.58 mm/yr. The middle of paragraph 63 becomes “The Stanley data suggest that the rate of change of sea level in East Falkland since 1992 has been approximately 2.6 mm/yr, a rate supported by information from satellite altimetry.” These small GIA model corrections have no bearing on the main findings of our paper on the difference in the rates of sea level change between the historical (1842 to present-day) and recent (last 2 decades) epoch

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

Determination of Probiotic and/or Chlortetracycline Inclusion Effects on Nursery Pig Growth Performance

A total of 300 nursery pigs (DNA 200 × 400, Columbus, NE; initially 13.0 lb BW) were used in a 42-d study evaluating the effects of feeding chlortetracycline (CTC) in combination with probiotics on nursery pig performance. Probiotics are a class of antimicrobial alternatives designed to enhance growth performance and digestive tract health. Pigs were weaned at approximately 21 d of age and allotted to pens based on initial BW. Pigs were fed a common pelleted starter diet for 4 d and then weighed, and pens were allotted to 1 of 6 dietary treatments based on BW in a completely randomized design. The treatments were arranged in a 2 × 3 factorial with main effects of chlortetracycline (0 vs. CTC at 400 g/ton from d 0 to 42) and probiotic (0 vs. 1 lb/ton Bioplus 2B (Chr. Hansen USA, Inc., Milwaukee, WI)) vs. 1 lb/ton Poultry Star (Biomin America, Inc., San Antonio, TX). Experimental diets were fed in 2 phases (Phase 1: d 0 to 14 and Phase 2: d 14 to 42) and fed in meal form. On d 14 and 28, CTC was removed from the diet according to FDA regulations. For overall performance, there were no interactions (P \u3e 0.05) between added probiotics and CTC. However, pigs fed CTC had improved (P \u3c 0.001) ADG, ADFI, and overall BW compared with those fed diets without CTC. While adding Poultry Star to the diet increased (P \u3c 0.05) BW and ADFI on d 14, there were no consistent benefits of feeding either probiotic alone or in combination with CTC

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

Interactive effects of modified tall oil and fat source on growth performance and carcass characteristics of finishing barrows and gilts

A total of 144 pigs (initially 90 lb) was used to determine the interactive effects of fat source: none (NF), 6% choice white grease (CWG), or 6% poultry fat (PF); modified tall oil (MTO, 0 or .5%); and sex (barrows or gilts) on growth performance and carcass characteristics. Regardless of fat source, MTO improved belly firmness but did not influence growth performance. Gilts were leaner, had increased loin muscle area, and had softer bellies compared to barrows. Added fat decreased ADFI and improved F/G. Pigs fed PF had the best F/G, but the fattest carcasses and softest loins and bellies.; Swine Day, Manhattan, KS, November 18, 199