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1. Privacy-Preserving Distributed Zeroth-Order Optimization

Author

Gratton, C., Venkategowda, N. K. D., Arablouei, R., and Werner, S.

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

We develop a privacy-preserving distributed algorithm to minimize a regularized empirical risk function when the first-order information is not available and data is distributed over a multi-agent network. We employ a zeroth-order method to minimize the associated augmented Lagrangian function in the primal domain using the alternating direction method of multipliers (ADMM). We show that the proposed algorithm, named distributed zeroth-order ADMM (D-ZOA), has intrinsic privacy-preserving properties. Unlike the existing privacy-preserving methods based on the ADMM where the primal or the dual variables are perturbed with noise, the inherent randomness due to the use of a zeroth-order method endows D-ZOA with intrinsic differential privacy. By analyzing the perturbation of the primal variable, we show that the privacy leakage of the proposed D-ZOA algorithm is bounded. In addition, we employ the moments accountant method to show that the total privacy leakage grows sublinearly with the number of ADMM iterations. D-ZOA outperforms the existing differentially private approaches in terms of accuracy while yielding the same privacy guarantee. We prove that D-ZOA converges to the optimal solution at a rate of $\mathcal{O}(1/M)$ where $M$ is the number of ADMM iterations. The convergence analysis also reveals a practically important trade-off between privacy and accuracy. Simulation results verify the desirable privacy-preserving properties of D-ZOA and its superiority over a state-of-the-art algorithm as well as its network-wide convergence to the optimal solution.

Published
2020

2. Reducing Native Ant Abundance Decreases Predation Rates in Midwestern Grasslands.

Author

Wills, Bd, Kim, Tn, Fox, Af, Gratton, C, and Landis, Da

Subjects
Lasius neoniger, diversity, natural enemies, predation services, prey suppression, Animals, Ants, Grassland, Insecta, Ovum, Predatory Behavior, Lasius neoniger, Zoology, Entomology
Abstract

Diverse and robust predator communities are important for effective prey suppression in natural and managed communities. Ants are ubiquitous components of terrestrial systems but their contributions to natural prey suppression is relatively understudied in temperate regions. Growing evidence suggests that ants can play a significant role in the removal of insect prey within grasslands, but their impact is difficult to separate from that of nonant predators. To test how ants may contribute to prey suppression in grasslands, we used poison baits (with physical exclosures) to selectively reduce the ant population in common garden settings, then tracked ant and nonant ground predator abundance and diversity, and removal of sentinel egg prey for 7 wk. We found that poison baits reduced ant abundance without a significant negative impact on abundance of nonant ground predators, and that a reduction in ant abundance decreased the proportion of sentinel prey eggs removed. Even a modest decrease (~20%) in abundance of several ant species, including the numerically dominant Lasius neoniger Emery (Hymenoptera: Formicidae), significantly reduced sentinel prey removal rates. Our results suggest that ants disproportionately contribute to ground-based predation of arthropod prey in grasslands. Changes in the amount of grasslands on the landscape and its management may have important implications for ant prevalence and natural prey suppression services in agricultural landscapes.

Published
2019

9. When forewarned is not forearmed: The paradoxical effect of single warnings attached to repeated fake news

Author

Gagnon-St-Pierre É, Markovits H, and Gratton C

Subjects
History, business.industry, Internet privacy, Fake news, business
Abstract

The fight against misinformation on social media and the internet in general has gained tremendous attention in the recent years. One way of combatting this has been to attach warnings tags about verified content. In this paper, we report two studies that examine the potential effects of a single warning tag in a context where the gist of a False claim is often repeated without the tag, which, given the reality of the way that information is transmitted, can be said to be an ecologically realistic model. Study 1 showed that the placement of the tag makes no difference, while a simple tag produces higher levels of belief than a tag with explanatory details. Remarkably, the simple tag produces a large increase in belief in the False claim. Study 2 showed that enhancing the distinctive character of a tag by adding irrelevant information to it produces a relative increase in believability equivalent to that obtained by making the claim graphically more distinctive. However, repeating a simple tag more often reduces this effect. These results indicate that the effects of warning tags are a combination of adding to the distinctiveness of the memory trace of the False claim (which makes this more believable by increasing fluency) and the semantic content of the tag (which reduces belief).

Published
2020

13. A global synthesis reveals biodiversity-mediated benefits for crop production

Author

Dainese, M., Martin, E. A., Aizen, Marcelo A., Albrecht, M., Bartomeus, I., Bommarco, R., Carvalheiro, L. G., Chaplin-Kramer, R., Gagic, V., Garibaldi, Lucas A., Ghazoul, J., Grab, H., Jonsson, M., Karp, D. S., Kennedy, Cristina M., Kleijn, D., Kremen, C., Landis, D. A., Letourneau, D. K., Marini, Lorenzo, Poveda, K., Rader, R., Smith, H. G., Tscharntke, T., Andersson, G. K. S., Badenhausser, I., Baensch, S., Bezerra, A. D. M., Bianchi, F. J. J. A., Boreux, V., Bretagnolle, V., Caballero-López, Berta, Cavigliasso, P., Cetkovic, Aleksandar, Chacoff, Natacha P., Classen, A., Cusser, S., Da Silva E Silva, F. D., Arjen De Groot, G., Dudenhöffer, J. H., Ekroos, J., Fijen, T., Franck, P., Freitas, B. M., Garratt, M. P. D., Gratton, C., Hipólito, J., Holzschuh, A., Hunt, L., Zaragoza-Trello, C., Dainese, M., Martin, E. A., Aizen, Marcelo A., Albrecht, M., Bartomeus, I., Bommarco, R., Carvalheiro, L. G., Chaplin-Kramer, R., Gagic, V., Garibaldi, Lucas A., Ghazoul, J., Grab, H., Jonsson, M., Karp, D. S., Kennedy, Cristina M., Kleijn, D., Kremen, C., Landis, D. A., Letourneau, D. K., Marini, Lorenzo, Poveda, K., Rader, R., Smith, H. G., Tscharntke, T., Andersson, G. K. S., Badenhausser, I., Baensch, S., Bezerra, A. D. M., Bianchi, F. J. J. A., Boreux, V., Bretagnolle, V., Caballero-López, Berta, Cavigliasso, P., Cetkovic, Aleksandar, Chacoff, Natacha P., Classen, A., Cusser, S., Da Silva E Silva, F. D., Arjen De Groot, G., Dudenhöffer, J. H., Ekroos, J., Fijen, T., Franck, P., Freitas, B. M., Garratt, M. P. D., Gratton, C., Hipólito, J., Holzschuh, A., Hunt, L., and Zaragoza-Trello, C.

Abstract

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.

Published
2019

14. Authorship profiling without using topical information : Notebook for PAN at CLEF 2018

Author

Karlgren, Jussi, Esposito, L., Gratton, C., Kanerva, P., Karlgren, Jussi, Esposito, L., Gratton, C., and Kanerva, P.

Abstract

This paper describes an experiment made for the PAN 2018 shared task on author profiling. The task is to distinguish female from male authors of microblog posts published on Twitter using no extraneous information except what is in the posts; this experiment focusses on using non-topical information from the posts, rather than gender differences in referential content., QC 20180905

Published
2018

15. Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

Author

Karp, DS, Chaplin-Kramer, R, Meehan, TD, Martin, EA, DeClerck, F, Grab, H, Gratton, C, Hunt, L, Larsen, AE, Martinez-Salinas, A, O'Rourke, ME, Rusch, A, Poveda, K, Jonsson, M, Rosenheim, JA, Schellhorn, NA, Tscharntke, T, Wratten, SD, Zhang, W, Iverson, AL, Adler, LS, Albrecht, M, Alignier, A, Angelella, GM, Anjum, MZ, Avelino, J, Batary, P, Baveco, JM, Bianchi, FJJA, Birkhofer, K, Bohnenblust, EW, Bommarco, R, Brewer, MJ, Caballero-Lopez, B, Carriere, Y, Carvalheiro, LG, Cayuela, L, Centrella, M, Cetkovic, A, Henri, DC, Chabert, A, Costamagna, AC, De la Mora, A, de Kraker, J, Desneux, N, Diehl, E, Diekoetter, T, Dormann, CF, Eckberg, JO, Entling, MH, Fiedler, D, Franck, P, van Veen, FJF, Frank, T, Gagic, V, Garratt, MPD, Getachew, A, Gonthier, DJ, Goodell, PB, Graziosi, I, Groves, RL, Gurr, GM, Hajian-Forooshani, Z, Heimpel, GE, Herrmann, JD, Huseth, AS, Inclan, DJ, Ingrao, AJ, Iv, P, Jacot, K, Johnson, GA, Jones, L, Kaiser, M, Kaser, JM, Keasar, T, Kim, TN, Kishinevsky, M, Landis, DA, Lavandero, B, Lavigne, C, Le Ralec, A, Lemessa, D, Letourneau, DK, Liere, H, Lu, Y, Lubin, Y, Luttermoser, T, Maas, B, Mace, K, Madeira, F, Mader, V, Cortesero, AM, Marini, L, Martinez, E, Martinson, HM, Menozzi, P, Mitchell, MGE, Miyashita, T, Molina, GAR, Molina-Montenegro, MA, O'Neal, ME, Opatovsky, I, Ortiz-Martinez, S, Nash, M, Ostman, O, Ouin, A, Pak, D, Paredes, D, Parsa, S, Parry, H, Perez-Alvarez, R, Perovic, DJ, Peterson, JA, Petit, S, Philpott, SM, Plantegenest, M, Plecas, M, Pluess, T, Pons, X, Potts, SG, Pywell, RF, Ragsdale, DW, Rand, TA, Raymond, L, Ricci, B, Sargent, C, Sarthou, J-P, Saulais, J, Schackermann, J, Schmidt, NP, Schneider, G, Schuepp, C, Sivakoff, FS, Smith, HG, Whitney, KS, Stutz, S, Szendrei, Z, Takada, MB, Taki, H, Tamburini, G, Thomson, LJ, Tricault, Y, Tsafack, N, Tschumi, M, Valantin-Morison, M, Mai, VT, van der Werf, W, Vierling, KT, Werling, BP, Wickens, JB, Wickens, VJ, Woodcock, BA, Wyckhuys, K, Xiao, H, Yasuda, M, Yoshioka, A, Zou, Y, Karp, DS, Chaplin-Kramer, R, Meehan, TD, Martin, EA, DeClerck, F, Grab, H, Gratton, C, Hunt, L, Larsen, AE, Martinez-Salinas, A, O'Rourke, ME, Rusch, A, Poveda, K, Jonsson, M, Rosenheim, JA, Schellhorn, NA, Tscharntke, T, Wratten, SD, Zhang, W, Iverson, AL, Adler, LS, Albrecht, M, Alignier, A, Angelella, GM, Anjum, MZ, Avelino, J, Batary, P, Baveco, JM, Bianchi, FJJA, Birkhofer, K, Bohnenblust, EW, Bommarco, R, Brewer, MJ, Caballero-Lopez, B, Carriere, Y, Carvalheiro, LG, Cayuela, L, Centrella, M, Cetkovic, A, Henri, DC, Chabert, A, Costamagna, AC, De la Mora, A, de Kraker, J, Desneux, N, Diehl, E, Diekoetter, T, Dormann, CF, Eckberg, JO, Entling, MH, Fiedler, D, Franck, P, van Veen, FJF, Frank, T, Gagic, V, Garratt, MPD, Getachew, A, Gonthier, DJ, Goodell, PB, Graziosi, I, Groves, RL, Gurr, GM, Hajian-Forooshani, Z, Heimpel, GE, Herrmann, JD, Huseth, AS, Inclan, DJ, Ingrao, AJ, Iv, P, Jacot, K, Johnson, GA, Jones, L, Kaiser, M, Kaser, JM, Keasar, T, Kim, TN, Kishinevsky, M, Landis, DA, Lavandero, B, Lavigne, C, Le Ralec, A, Lemessa, D, Letourneau, DK, Liere, H, Lu, Y, Lubin, Y, Luttermoser, T, Maas, B, Mace, K, Madeira, F, Mader, V, Cortesero, AM, Marini, L, Martinez, E, Martinson, HM, Menozzi, P, Mitchell, MGE, Miyashita, T, Molina, GAR, Molina-Montenegro, MA, O'Neal, ME, Opatovsky, I, Ortiz-Martinez, S, Nash, M, Ostman, O, Ouin, A, Pak, D, Paredes, D, Parsa, S, Parry, H, Perez-Alvarez, R, Perovic, DJ, Peterson, JA, Petit, S, Philpott, SM, Plantegenest, M, Plecas, M, Pluess, T, Pons, X, Potts, SG, Pywell, RF, Ragsdale, DW, Rand, TA, Raymond, L, Ricci, B, Sargent, C, Sarthou, J-P, Saulais, J, Schackermann, J, Schmidt, NP, Schneider, G, Schuepp, C, Sivakoff, FS, Smith, HG, Whitney, KS, Stutz, S, Szendrei, Z, Takada, MB, Taki, H, Tamburini, G, Thomson, LJ, Tricault, Y, Tsafack, N, Tschumi, M, Valantin-Morison, M, Mai, VT, van der Werf, W, Vierling, KT, Werling, BP, Wickens, JB, Wickens, VJ, Woodcock, BA, Wyckhuys, K, Xiao, H, Yasuda, M, Yoshioka, A, and Zou, Y

Abstract

The idea that noncrop habitat enhances pest control and represents a win-win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win-win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.

Published
2018

16. Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

Author

National Science Foundation (US), Karp, D.S., Chaplin-Kramer, R., Meehan, T. D., Martin, E. A., DeClerck, F., Grab, H., Gratton, C., Hunt, L., Larsen, A. E., Martínez-Salinas, A., O'Rourke, M. E., Rusch, A., Poveda, K., Jonsson, M., Rosenheim, J. A., Schellhorn, N. A., Tscharntke, T., Wratten, S. D., Zhang, W., Iverson, A. L., Adler, L. S., Albrecht, M., Alignier, A., Angelella, G. M., Anjum, M. Z., Avelino, J., Batáry, P., Baveco, J. M., Bianchi, F.J.J.A., Birkhofer, K., Bohnenblust, E. W., Bommarco, R., Brewer, M. J., Caballero-López, Berta, Carrière, Y., Carvalheiro, L.G., Cayuela, Luis, Centrella, M., Cetkovic, Aleksandar, Henri, D. C., Chabert, A., Costamagna, A. C., De la Mora, A., Kraker, Joop de, Desneux, N., Diehl, E., Diekötter, T., Dormann, C. F., Eckberg, J. O., Madeira, F., Paredes, Daniel, Pons, Xavier, National Science Foundation (US), Karp, D.S., Chaplin-Kramer, R., Meehan, T. D., Martin, E. A., DeClerck, F., Grab, H., Gratton, C., Hunt, L., Larsen, A. E., Martínez-Salinas, A., O'Rourke, M. E., Rusch, A., Poveda, K., Jonsson, M., Rosenheim, J. A., Schellhorn, N. A., Tscharntke, T., Wratten, S. D., Zhang, W., Iverson, A. L., Adler, L. S., Albrecht, M., Alignier, A., Angelella, G. M., Anjum, M. Z., Avelino, J., Batáry, P., Baveco, J. M., Bianchi, F.J.J.A., Birkhofer, K., Bohnenblust, E. W., Bommarco, R., Brewer, M. J., Caballero-López, Berta, Carrière, Y., Carvalheiro, L.G., Cayuela, Luis, Centrella, M., Cetkovic, Aleksandar, Henri, D. C., Chabert, A., Costamagna, A. C., De la Mora, A., Kraker, Joop de, Desneux, N., Diehl, E., Diekötter, T., Dormann, C. F., Eckberg, J. O., Madeira, F., Paredes, Daniel, and Pons, Xavier

Abstract

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.

Published
2018

18. Cholinergic, But Not Dopaminergic or Noradrenergic, Enhancement Sharpens Visual Spatial Perception in Humans

Author

Gratton, C., Yousef, S., Aarts, E., D'Esposito, M., Silver, M.A., Gratton, C., Yousef, S., Aarts, E., D'Esposito, M., and Silver, M.A.

Abstract

Contains fulltext : 180499.pdf (publisher's version ) (Open Access), The neuromodulator acetylcholine modulates spatial integration in visual cortex by altering the balance of inputs that generate neuronal receptive fields. These cholinergic effects may provide a neurobiological mechanism underlying the modulation of visual representations by visual spatial attention. However, the consequences of cholinergic enhancement on visuospatial perception in humans are unknown. We conducted two experiments to test whether enhancing cholinergic signaling selectively alters perceptual measures of visuospatial interactions in human subjects. In Experiment 1, a double-blind placebo-controlled pharmacology study, we measured how flanking distractors influenced detection of a small contrast decrement of a peripheral target, as a function of target-flanker distance. We found that cholinergic enhancement with the cholinesterase inhibitor donepezil improved target detection, and modeling suggested that this was mainly due to a narrowing of the extent of facilitatory perceptual spatial interactions. In Experiment 2, we tested whether these effects were selective to the cholinergic system or would also be observed following enhancements of related neuromodulators dopamine or norepinephrine. Unlike cholinergic enhancement, dopamine (bromocriptine) and norepinephrine (guanfacine) manipulations did not improve performance or systematically alter the spatial profile of perceptual interactions between targets and distractors. These findings reveal mechanisms by which cholinergic signaling influences visual spatial interactions in perception and improves processing of a visual target among distractors, effects that are notably similar to those of spatial selective attention.

Published
2017

20. Canadian Surgery Forum 2019: Montreal, Que. Sept. 5–7, 2019.

Author

Huynh, C., Wong-Chong, N., Vourtzoumis, P., Lim, S., Marini, W., Johal, G., Strickland, M., Madani, A., Clement, E., Lee, A., Ericson, A., Gratton, C., Ryan, J., Clements, T., Kim, M., Ball, C., Widder, S., DeGirolamo, D., Hwang, D., and Kleiman, A.

Subjects
INTRA-abdominal infections, SURGERY, MEDICAL students, MEDICAL care
Published
2019
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22. Bird communities in future bioenergy landscapes of the Upper Midwest

Author

Gratton, C., Meehan, T. D., and Hurlbert, A. H.

Abstract

Mandates for biofuel and renewable electricity are creating incentives for biomass production in agricultural landscapes of the Upper Midwest. Different bioenergy crops are expected to vary in their effects on biodiversity and ecosystem services. Here, we use data from the North American Breeding Bird Survey to forecast the impact of potential bioenergy crops on avian species richness and the number of bird species of conservation concern in Midwestern landscapes. Our analysis suggests that expanded production of annual bioenergy crops (e.g., corn and soybeans) on marginal land will lead to declines in avian richness between 7% and 65% across 20% of the region, and will make managing at-risk species more challenging. In contrast, replacement of annual with diverse perennial bioenergy crops (e.g., mixed grasses and forbs) is expected to bring increases in avian richness between 12% and 207% across 20% of the region, and possibly aid the recovery of several species of conservation concern.

Published
2010
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23. Great Britain

Author

Gratton, C and Veal, AJ

Published
2005

26. International Comparisons of Sports participation in European Countries: an Update of the COMPASS Project

Author

Gratton, C, Rowe, N, Veal, AJ, Gratton, C, Rowe, N, and Veal, AJ

Abstract

© 2011, Copyright 2011 Taylor and Francis Group LLC. This paper looks back to an international comparative study of sports participation in seven European countries that was carried out in the late 1990s, COMPASS 1999. The original COMPASS study used data from the 1995-1997 period. This paper reviews the COMPASS framework and results, considers what new evidence is available to update the original COMPASS results, and considers what changes would be needed to the COMPASS approach if a new comparative study were undertaken today. Finally, the paper attempts to find explanations for the European pattern of sports participation revealed.

Published
2011

47. Urine screening with the MS-2

Author

Hoban, D J, Koss, J C, Gratton, C A, and Ronald, A R

Abstract

A study was undertaken to evaluate the effectiveness of the MS-2 (Abbott Laboratories, Dallas, Tex.) in screening urine specimens in a large clinical laboratory. A total of 15,319 urine specimens (9,954 midstream specimens and 5,365 catheter specimens) were evaluated with the MS-2 and by a surface streak procedure. The study was conducted in two phases, differing in that phase II urine specimens were evaluated in the MS-2 by using a program software update (03.01). For midstream urine specimens, MS-2 detection rates in phases I and II were, respectively, 94.5 and 94.3% at a plate count of greater than 10(5) CFU/ml, 74.4 and 65.3% at plate counts of 5 X 10(4) to 1 X 10(5) CFU/ml, 55.0 and 52.4% at plate counts of 1 X 10(4) to 5 X 10(4) CFU/ml, 31.2 and 20.5% at plate counts of 10(3) to 10(4) CFU/ml, and 15.7 and 6.4% at plate counts of less than 10(3) CFU/ml. For catheter urine specimens, the MS-2 detection rates in phases I and II were, respectively, 95.4 and 96.8% at plate counts greater than 10(5) CFU/ml, 74.4 and 85.7% at plate counts of 5 X 10(4) to 1 X 10(5) CFU/ml, 50.0 and 44.4% at plate counts 10(4) to 5 X 10(4) CFU/ml, 25.6 and 14.9% at plate counts of 10(3) to 10(4) CFU/ml, and 14.7 and 5.2% at plate counts less than 10(3) CFU/ml.

Published
1983
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