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Showing papers by "York University published in 2005"


Journal ArticleDOI
Takashi Matsumoto1, Jianzhong Wu1, Hiroyuki Kanamori1, Yuichi Katayose1  +262 moreInstitutions (25)
11 Aug 2005-Nature
TL;DR: A map-based, finished quality sequence that covers 95% of the 389 Mb rice genome, including virtually all of the euchromatin and two complete centromeres, and finds evidence for widespread and recurrent gene transfer from the organelles to the nuclear chromosomes.
Abstract: Rice, one of the world's most important food plants, has important syntenic relationships with the other cereal species and is a model plant for the grasses. Here we present a map-based, finished quality sequence that covers 95% of the 389 Mb genome, including virtually all of the euchromatin and two complete centromeres. A total of 37,544 non-transposable-element-related protein-coding genes were identified, of which 71% had a putative homologue in Arabidopsis. In a reciprocal analysis, 90% of the Arabidopsis proteins had a putative homologue in the predicted rice proteome. Twenty-nine per cent of the 37,544 predicted genes appear in clustered gene families. The number and classes of transposable elements found in the rice genome are consistent with the expansion of syntenic regions in the maize and sorghum genomes. We find evidence for widespread and recurrent gene transfer from the organelles to the nuclear chromosomes. The map-based sequence has proven useful for the identification of genes underlying agronomic traits. The additional single-nucleotide polymorphisms and simple sequence repeats identified in our study should accelerate improvements in rice production.

3,423 citations


Proceedings Article
05 Dec 2005
TL;DR: A model of bottom-up overt attention is proposed based on the principle of maximizing information sampled from a scene and is achieved in a neural circuit, which is demonstrated as having close ties with the circuitry existent in die primate visual cortex.
Abstract: A model of bottom-up overt attention is proposed based on the principle of maximizing information sampled from a scene. The proposed operation is based on Shannon's self-information measure and is achieved in a neural circuit, which is demonstrated as having close ties with the circuitry existent in die primate visual cortex. It is further shown that the proposed salicney measure may be extended to address issues that currently elude explanation in the domain of saliency based models. Results on natural images are compared with experimental eye tracking data revealing the efficacy of the model in predicting the deployment of overt attention as compared with existing efforts.

1,201 citations


Journal ArticleDOI
TL;DR: In this article, the authors examined how managers' perceptions of different types of stakeholder influences in the Canadian forestry industry affect the types of sustainability practices that their firms adopt and found that the industry and its stakeholders have moved beyond a focus on early stages of sustainability performance such as pollution control and eco-efficiency.
Abstract: We examined how managers' perceptions of different types of stakeholder influences in the Canadian forestry industry affect the types of sustainability practices that their firms adopt. Both influences involving withholding of resources by social and ecological stakeholders and those involving directed usage of resources from economic stakeholders were found to drive such practices. We found that the industry and its stakeholders have moved beyond a focus on early stages of sustainability performance such as pollution control and eco-efficiency. However, more advanced practices, such as those involving the redefinition of business and industrial ecosystems where firms locate in a region so that they can exchange and utilize wastes generated by other firms, are in their infancy. Stakeholders and firms in the industry are focused on the intermediate sustainability phases involving recirculation of materials and redesign of processes including sustainable harvesting of lumber. Copyright © 2004 John Wiley & Sons, Ltd.

1,145 citations


Reference EntryDOI
15 Oct 2005
TL;DR: In this paper, the authors discuss MCPs that can be used to investigate simple pairwise differences between treatment group means, as well as complex comparisons (i.e., nonpairwise comparisons) between treatment groups means.
Abstract: Multiple comparison procedures (MCPs) are frequently adopted by applied researchers to locate specific differences between treatment groups. That is, omnibus test statistics, such as the analysis of variance F test, can only signify that effects are present, not which specific groups differ from one another (when there are more than two groups). In our paper, we discuss MCPs that can be used to investigate simple pairwise differences between treatment group means, as well as MCPs that can be used to examine complex comparisons (i.e., nonpairwise comparisons) between treatment group means. In particular, we discuss simultaneous as well as stepwise MCPs, emphasizing procedures that can be utilized when the derivational assumptions of the classical procedures of normality and variance homogeneity do not hold. Keywords: pairwise and complex comparisons; simultaneous and stepwise procedures; Type I error rates; robust procedures

923 citations


Journal ArticleDOI
Naomi Adelson1
TL;DR: Health disparities are indicators of a relative disproportionate burden of disease on a particular population as mentioned in this paper, i.e., those indicators that a particular group of individuals have a higher burden of ill health and social suffering.
Abstract: Health disparities are, first and foremost, those indicators of a relative disproportionate burden of disease on a particular population. Health inequities point to the underlying causes of the disparities, many if not most of which sit largely outside of the typically constituted domain of “health”. The literature reviewed for this synthesis document indicates that time and again health disparities are directly and indirectly associated with social, economic, cultural and political inequities; the end result of which is a disproportionate burden of ill health and social suffering upon the Aboriginal populations of Canada. In analyses of health disparities, it is as important to navigate the interstices between the person and the wider social and historical contexts as it is to pay attention to the individual effects of inequity. Research and policy must address the contemporary realities of Aboriginal health and well-being, including the individual and community-based effects of health disparities and the direct and indirect sources of those disparities.

826 citations


Posted Content
TL;DR: In this paper, the authors extend the model-free implied volatility to asset price processes with jumps and develop a simple method for implementing it using observed option prices, and perform a direct test of the informational efficiency of the option market using the model free implied volatility.
Abstract: Britten-Jones and Neuberger (2000) derived a model-free implied volatility under the diffusion assumption. In this article, we extend their model-free implied volatility to asset price processes with jumps and develop a simple method for implementing it using observed option prices. In addition, we perform a direct test of the informational efficiency of the option market using the model-free implied volatility. Our results from the Standard & Poor’s 500 index (SPX) options suggest that the model-free implied volatility subsumes all information contained in the Black-Scholes (B-S) implied volatility and past realized volatility and is a more efficient forecast for future realized volatility.

825 citations


Journal ArticleDOI
TL;DR: The Atmospheric Chemistry Experiment (ACE) is a Canadian satellite mission for remote sensing of the Earth's atmosphere that was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003.
Abstract: SCISAT-1, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003. The primary ACE instrument is a high spectral resolution (0.02 cm-1) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 μm (750-4400 cm-1). The satellite also features a dual spectrophotometer known as MAESTRO with wavelength coverage of 285-1030 nm and spectral resolution of 1-2 nm. A pair of filtered CMOS detector arrays records images of the Sun at 0.525 and 1.02 μm. Working primarily in solar occultation, the satellite provides altitude profile information (typically 10-100 km) for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest, as well as atmospheric extinction profiles over the latitudes 85°N to 85°S. This paper presents a mission overview and some of the first scientific results. Copyright 2005 by the American Geophysical Union.

807 citations


Journal ArticleDOI
TL;DR: The Third Data Release of the Sloan Digital Sky Survey (SDSS) as mentioned in this paper contains data taken up through 2003 June, including imaging data in five bands over 5282 deg2, photometric and astrometric catalogs of the 141 million objects detected in these imaging data, and spectra of 528,640 objects selected over 4188 deg2.
Abstract: This paper describes the Third Data Release of the Sloan Digital Sky Survey (SDSS). This release, containing data taken up through 2003 June, includes imaging data in five bands over 5282 deg2, photometric and astrometric catalogs of the 141 million objects detected in these imaging data, and spectra of 528,640 objects selected over 4188 deg2. The pipelines analyzing both images and spectroscopy are unchanged from those used in our Second Data Release.

734 citations


Journal ArticleDOI
TL;DR: In this article, the authors extend the model-free implied volatility to asset price processes with jumps and develop a simple method for implementing it using observed option prices, and perform a direct test of the informational efficiency of the option market using the model free implied volatility.
Abstract: Britten-Jones and Neuberger (2000) derived a model-free implied volatility under the diffusion assumption. In this article, we extend their model-free implied volatility to asset price processes with jumps and develop a simple method for implementing it using observed option prices. In addition, we perform a direct test of the informational efficiency of the option market using the model-free implied volatility. Our results from the Standard & Poor's 500 index (SPX) options suggest that the model-free implied volatility subsumes all information contained in the Black--Scholes (B--S) implied volatility and past realized volatility and is a more efficient forecast for future realized volatility. Copyright 2005, Oxford University Press.

712 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigate the extent to which the Palomar-Green (PG) Bright Quasar Survey (BQS) is complete and representative of the general quasar population by comparing with imaging and spectroscopy from the Sloan Digital Sky Survey.
Abstract: We investigate the extent to which the Palomar-Green (PG) Bright Quasar Survey (BQS) is complete and representative of the general quasar population by comparing with imaging and spectroscopy from the Sloan Digital Sky Survey. A comparison of SDSS and PG photometry of both stars and quasars reveals the need to apply a color and magnitude recalibration to the PG data. Using the SDSS photometric catalog, we define the PG's parent sample of objects that are not main-sequence stars and simulate the selection of objects from this parent sample using the PG photometric criteria and errors. This simulation shows that the effective U-B cut in the PG survey is U-B 0.5 are inherently rare in bright surveys in any case). We find no evidence for any other systematic incompleteness when comparing the distributions in color, redshift, and FIRST radio properties of the BQS and a BQS-like subsample of the SDSS quasar sample. However, the application of a bright magnitude limit biases the BQS toward the inclusion of objects which are blue in g-i, in particular compared to the full range of g-i colors found among the i-band limited SDSS quasars, and even at i-band magnitudes comparable to those of the BQS objects.

643 citations



Journal ArticleDOI
TL;DR: In this article, a Li-Cor 1800-12 Integrating Sphere coupled with a 200 Am diameter single mode fiber to an Ocean Optics model USB2000 spectrometer was used for measuring the optical properties of reflectance and transmittance with a subsample of 605 leaves.

Journal ArticleDOI
TL;DR: Recent progress in assembling the tree of eukaryotes is reviewed, describing the major evidence for each supergroup, and where gaps in the authors' knowledge remain.
Abstract: Recent advances in resolving the tree of eukaryotes are converging on a model composed of a few large hypothetical 'supergroups', each comprising a diversity of primarily microbial eukaryotes (protists, or protozoa and algae). The process of resolving the tree involves the synthesis of many kinds of data, including single-gene trees, multigene analyses, and other kinds of molecular and structural characters. Here, we review the recent progress in assembling the tree of eukaryotes, describing the major evidence for each supergroup, and where gaps in our knowledge remain. We also consider other factors emerging from phylogenetic analyses and comparative genomics, in particular lateral gene transfer, and whether such factors confound our understanding of the eukaryotic tree.

Journal ArticleDOI
TL;DR: In goldfish, nutritional status can modify the expression of mRNAs encoding a number of orexigenic peptides, which provides further evidence for their roles as appetite regulators: (1) brain mRNA expression of CCK, CART, tachykinins, galanin, ghrelin, and NPY undergo peri-prandial variations; and (2) fasting increases the brain RNA expression of NPY, AgRP, and gh Relin as well as serum

Journal ArticleDOI
TL;DR: This article focused on a representative sample from 200 teacher candidates' responses to Peggy McIntosh's article, "White Privilege: unpacking the invisible knapsack" and explored several strategies that teacher candidates employed to avoid addressing whiteness and its attendant privileges in Canadian society.
Abstract: This qualitative study focuses on a representative sample from 200 teacher candidates' responses to Peggy McIntosh's article, ‘White privilege: unpacking the invisible knapsack’. The notion and understanding of whiteness and white privilege were explored revealing several strategies that teacher candidates employed to avoid addressing whiteness and its attendant privileges in Canadian society. We analyse three primary strategies that the teacher candidates employed: ideological incongruence, liberalist notions of individualism and meritocracy, and the negation of white capital. Some implications of this study are that teacher education must help candidates understand their own racial identity formation and provide the learning space to work with the range of emotions and feelings of indignation that evolve from an exposure to white privilege and the ‘myth of meritocracy’.

Journal ArticleDOI
TL;DR: The results showed a general increment in reading ability for all the bilingual children but a larger advantage for children learning two alphabetic systems, which depends on the relation between the two languages and writing systems.
Abstract: Four groups of children in first grade were compared on early literacy tasks. Children in three of the groups were bilingual, each group representing a different combination of language and writing system, and children in the fourth group were monolingual speakers of English. All the bilingual children used both languages daily and were learning to read in both languages. The children solved decoding and phonological awareness tasks, and the bilinguals completed all tasks in both languages. Initial differences between the groups in factors that contribute to early literacy were controlled in an analysis of covariance, and the results showed a general increment in reading ability for all the bilingual children but a larger advantage for children learning two alphabetic systems. Similarly, bilinguals transferred literacy skills across languages only when both languages were written in the same system. Therefore, the extent of the bilingual facilitation for early reading depends on the relation between the t...

Journal ArticleDOI
TL;DR: Standard scoring of the BFNE may not be optimal for patients with social anxiety disorder, and confirmatory factor analysis indicated a 2-factor solution to be more appropriate.
Abstract: The Brief Fear of Negative Evaluation Scale (BFNE; M. R. Leary, 1983a) is often used to assess fear of negative evaluation, the core feature of social anxiety disorder. However, few studies have examined its psychometric properties in large samples of socially anxious patients. Although the BFNE yields a single total score, confirmatory factor analysis indicated a 2-factor solution to be more appropriate, with the 1st factor consisting of all straightforwardly worded items (BFNE-S) and the 2nd of all reverse-scored items (BFNE-R). Support was obtained for the convergent and discriminant validity of the BFNE and BFNE-S, but not the BFNE-R. These results suggest that standard scoring of the BFNE may not be optimal for patients with social anxiety disorder.

Journal ArticleDOI
TL;DR: This article found a statistically significant, negative correlation between temperature and returns across the whole range of temperature and found that lower temperature can lead to aggression, while higher temperature could lead to both apathy and aggression.
Abstract: This study investigates whether stock market returns are related to temperature. Research in psychology has shown that temperature significantly affects mood, and mood changes in turn cause behavioral changes. Evidence suggests that lower temperature can lead to aggression, while higher temperature can lead to both apathy and aggression. Aggression could result in more risk-taking while apathy could impede risk-taking. We therefore expect lower temperature to be related to higher stock returns and higher temperature to be related to higher or lower stock returns, depending on the trade-off between the two competing effects. We examine many stock markets world-wide and find a statistically significant, negative correlation between temperature and returns across the whole range of temperature. Apathy dominates aggression when temperature is high. The observed negative correlation is robust to alternative tests and retains its statistical significance after controlling for various known anomalies.

Journal ArticleDOI
TL;DR: This paper examined the link between sexual orientation and adjustment in a community sample of 97 sexual minority (gay male, lesbian, bisexual, and questioning) high school students, taking into account their experiences of peer victimization and social support within peer and family contexts.
Abstract: The present study examined the link between sexual orientation and adjustment in a community sample of 97 sexual minority (gay male, lesbian, bisexual, and questioning) high school students, taking into account their experiences of peer victimization and social support within peer and family contexts. Adolescents were identified in a large-scale survey study conducted at 5 high schools. They were matched to a comparison sample of their heterosexual peers. Sexual minority adolescents reported more externalizing behaviors and depression symptoms than heterosexual youth. Compared to their heterosexual peers, sexual minority youth reported more sexual harassment, more bullying, less closeness with their mothers, and less companionship with their best friends. There were no significant differences between gay male, lesbian, bisexual, and questioning adolescents. Overall, both victimization and social support mediated the link between sexual orientation and psychosocial symptoms. Among sexual minority youth, the link between social support and externalizing was mediated by experiences of peer victimization. These findings highlight the contextual risk and protective factors associated with non-heterosexual sexual orientation in accounting for the emotional and behavioral problems in this population.

Journal ArticleDOI
TL;DR: It is proposed that the core tasks of PSFs raise unusual strategic and organizational challenges, the resolution of which affects organizational performance, and that PSF managers face a choice in designing structures between the retention and motivation of the professional workforce and transferring knowledge from partners to other professionals.
Abstract: Growing interest in knowledge as a competitive asset suggests the benefit of studying professional service firms (PSFs). These firms are highly successful examples of organizations whose ability to manage knowledge is critical to their success. Furthermore, they are worthy of study because they constitute a significant sector of the economy, whether measured by their size, numbers, or influence. Despite their significance, little is known of the determinants of their performance. This paper proposes that the core tasks of PSFs raise unusual strategic and organizational challenges, the resolution of which affects organizational performance. We elaborate the effects of reputation and diversification and contrast them to theory for goods-producing industries. We also hypothesize that PSF managers face a choice in designing structures between the retention and motivation of the professional workforce and transferring knowledge from partners to other professionals. These predictions are tested and supported by data from the largest 100 U.S. accounting firms for the period 1991-2000. The paper thus contributes to a theory of professional service firm management.

Proceedings Article
30 Aug 2005
TL;DR: A new external algorithm, LESS, is introduced that combines the best features of the initial algorithms proposed for maximals, based on divide-and-conquer, and it is proved its average-case running time is O(kn).
Abstract: Finding the maximals in a collection of vectors is relevant to many applications. The maximal set is related to the convex hull---and hence, linear optimization---and nearest neighbors. The maximal vector problem has resurfaced with the advent of skyline queries for relational databases and skyline algorithms that are external and relationally well behaved.The initial algorithms proposed for maximals are based on divide-and-conquer. These established good average and worst case asymptotic running times, showing it to be O(n) average-case. where n is the number of vectors. However, they are not amenable to externalizing. We prove, furthermore, that their performance is quite bad with respect to the dimensionality, k, of the problem. We demonstrate that the more recent external skyline algorithms are actually better behaved, although they do not have as good an apparent asymptotic complexity. We introduce a new external algorithm, LESS, that combines the best features of these. experimentally evaluate its effectiveness and improvement over the field, and prove its average-case running time is O(kn).

Journal ArticleDOI
TL;DR: Results suggest that PINK1 reduces the basal neuronal pro-apoptotic activity and protects neurons from staurosporine-induced apoptosis, and loss of this protective function may underlie the degeneration of nigral dopaminergic neurons in patients with Pink1 mutations.

Journal ArticleDOI
TL;DR: The present study used magneto-encephalography (MEG) to determine the neural correlates of the bilingual advantage previously reported for behavioral measures in conflict tasks, and found that the management of two language systems led to systematic changes in frontal executive functions.

Journal ArticleDOI
01 Oct 2005-Pain
TL;DR: Psychometric analyses suggested that the NRS was the preferred pain intensity scale, which had low error rates, and higher face, convergent, divergent and criterion validity than the other scales, which were not age‐related.
Abstract: The psychometric properties of pain intensity scales for the assessment of postoperative pain across the adult lifespan have not been reported. The objective of this study was to compare the feasibility and validity of the Numeric Rating Scale (NRS), Verbal Descriptor Scale (VDS), and Visual Analog Scale (horizontal (VAS-H) and vertical (VAS-V) line orientation) for the assessment of pain intensity in younger and older surgical patients. At 24h following surgery, 504 patients, who were receiving i.v. morphine via patient-controlled analgesia, completed the pain intensity measures and the McGill Pain Questionnaire (MPQ) in a randomized order. They were asked which scale was easiest to complete, the most accurate measure, and which they would most prefer to complete in the future, as an index of face validity. The amount of opioid self-administered was recorded. Age differences in postoperative pain intensity were not found. However, elderly patients obtained lower MPQ scores and self-administered less morphine than younger people. Psychometric analyses suggested that the NRS was the preferred pain intensity scale. It had low error rates, and higher face, convergent, divergent and criterion validity than the other scales. Most importantly, its properties were not age-related. The VDS also had a favourable profile with low error rates and good face, convergent and criterion validity. Finally, difficulties with VAS use among the elderly were identified, including high rates of unscorable data and low face validity. Its use with elderly postoperative patients should be discouraged.

Journal ArticleDOI
TL;DR: The authors found that bilingual children perform better than comparable monolinguals on tasks requiring control of attention to inhibit misleading information. But bilingual children did not perform better in early childhood, adulthood, and later adulthood.
Abstract: Previous research has shown that bilingual children perform better than comparable monolinguals on tasks requiring control of attention to inhibit misleading information The present paper reports a series of studies that traces this processing difference into adulthood and eventually aging The task used in all groups, from children to older adults, is the Simon task, a measure of stimulus-response incompatibility The results showed that bilinguals performed better than monolinguals in early childhood, adulthood, and later adulthood There was no difference in performance between monolinguals and bilinguals who were young adults, specifically university undergraduates Our interpretation is that performance is at its peak efficiency for that group and bilingualism offers no further boost The results are discussed in terms of the effect of bilingualism on control of attention and inhibition through the lifespan

Journal ArticleDOI
TL;DR: Direct evidence is provided for a representation in which individual faces are encoded by their direction and distance from a prototypical face, and the same neural population responds to faces falling along single identity axes within this space.
Abstract: fMRI (functional magnetic resonance imaging) studies on humans have shown a cortical area, the fusiform face area, that is specialized for face processing. An important question is how faces are represented within this area. This study provides direct evidence for a representation in which individual faces are encoded by their direction (facial identity) and distance (distinctiveness) from a prototypical (mean) face. When facial geometry (head shape, hair line, internal feature size and placement) was varied, the fMRI signal increased with increasing distance from the mean face. Furthermore, adaptation of the fMRI signal showed that the same neural population responds to faces falling along single identity axes within this space.

Book
15 Aug 2005
TL;DR: In this paper, the authors examine the fundamental issues of competitiveness and market power in the context of globalization and argue that the current climate of globalization signals the end of the nation-state as an effective manager of national economic policy.
Abstract: Countries are looking for ways to compete and increase their share of exports; this has led to the lowering of national borders and greater co-dependence. To many, this climate of globalization signals the end of the nation-state as an effective manager of national economic policy. In "States Against Markets" the contributors challenge this perceived threat to the nation-state. They examine the fundamental issues of competitiveness and market power. Some topics covered include a discussion of whether or not globalization is really a novel development, an assessment of the success of globalization as a means of convergence and uniformity across nations, an update on the Hayek vs. Keynes debate, an analysis of how all parties involved can maximize the benefits of globalization and an appraisal of the nation-state.

Journal ArticleDOI
TL;DR: Cognitive tasks and concepts are used increasingly in schizophrenia science and treatment and chronic stress, genes, brain disturbances, task structure, gender, and sociocultural background may all enhance the sensitivity of cognitive performance to schizophrenia.
Abstract: Cognitive tasks and concepts are used increasingly in schizophrenia science and treatment. Recent meta-analyses show that across a spectrum of research domains only cognitive measures distinguish a majority of schizophrenia patients from healthy people. Average effect sizes derived from common clinical tests of attention, memory, language, and reasoning are twice as large as those obtained in structural magnetic resonance imaging and positron emission tomography studies. Chronic stress, genes, brain disturbances, task structure, gender, and sociocultural background may all enhance the sensitivity of cognitive performance to schizophrenia. At the same time, disease heterogeneity and the presence of endophenotypes and subtypes within the patient population may place upper limits on the strength of any specific cognitive finding. Schizophrenia is a complex biobehavioral disorder that manifests itself primarily in cognition.

Posted Content
TL;DR: Investigating environment and strategic adaptations 12 years after Tan and Litschert examined these issues found that organizational environment and firm strategic adaptations have co-evolved over time and firms founded since 1990 are more proactive and innovative than firms that had existed in the previous stage.
Abstract: Economic reform in China has attracted growing attention from around the world owing to its significance for theory and practice. What has been largely missing in the literature is the temporal dimension, i.e., the changes over time in key variables such as organizational environment, firm strategic adaptations, and the performance implications. In this study, we investigate environment and strategic adaptations 12 years after Tan and Litschert examined these issues in 1990. Following a staged model, the study found that (1) organizational environment and firm strategic adaptations have co-evolved over time, (2) a new configuration has emerged and is related to improved performance, and (3) such a relationship is moderated by the stage during transition in which firms were founded. Specifically, firms founded since 1990 are more proactive and innovative than firms that had existed in the previous stage.

Journal ArticleDOI
TL;DR: In this paper, the authors found that the heterogeneous loss of glyoxal in the atmosphere is at least as important as gas phase loss mechanisms, including photolysis and reaction with hydroxyl radicals.
Abstract: from 1.05 � 10 � 11 to 23.1 � 10 � 11 mg particle � 1 min � 1 in the presence of � 5 ppb glyoxal. Uptake coefficients (g) of glyoxal varied from 8.0 � 10 � 4 to 7.3 � 10 � 3 with a median g =2 .9� 10 � 3 , observed for (NH4)2SO4 seed aerosols at 55% relative humidity. Increased g values were related to increased particle acidity, indicating that acid catalysis played a role in the heterogeneous mechanism. Experiments conducted at very low relative humidity, with the potential to be highly acidic, resulted in very low reactive uptake. These uptake coefficients indicated that the heterogeneous loss of glyoxal in the atmosphere is at least as important as gas phase loss mechanisms, including photolysis and reaction with hydroxyl radicals. Glyoxal lifetime due to heterogeneous reactions under typical ambient conditions was estimated to be thet = 5–287 min. In rural and remote areas the glyoxal uptake can lead to 5–257 ng m � 3 of secondary organic aerosols in 8 hours, consistent with recent ambient measurements.