Showing papers by "Université du Québec à Montréal published in 2009"

Lakes and reservoirs as regulators of carbon cycling and climate

Abstract: We explore the role of lakes in carbon cycling and global climate, examine the mechanisms influencing carbon pools and transformations in lakes, and discuss how the metabolism of carbon in the inland waters is likely to change in response to climate. Furthermore, we project changes as global climate change in the abundance and spatial distribution of lakes in the biosphere, and we revise the estimate for the global extent of carbon transformation in inland waters. This synthesis demonstrates that the global annual emissions of carbon dioxide from inland waters to the atmosphere are similar in magnitude to the carbon dioxide uptake by the oceans and that the global burial of organic carbon in inland water sediments exceeds organic carbon sequestration on the ocean floor. The role of inland waters in global carbon cycling and climate forcing may be changed by human activities, including construction of impoundments, which accumulate large amounts of carbon in sediments and emit large amounts of methane to the atmosphere. Methane emissions are also expected from lakes on melting permafrost. The synthesis presented here indicates that (1) inland waters constitute a significant component of the global carbon cycle, (2) their contribution to this cycle has significantly changed as a result of human activities, and (3) they will continue to change in response to future climate change causing decreased as well as increased abundance of lakes as well as increases in the number of aquatic impoundments.

Constraints on the magnitude and patterns of ocean cooling at the Last Glacial Maximum

Abstract: Observation-based reconstructions of sea surface temperature from relatively stable periods in the past, such as the Last Glacial Maximum, represent an important means of constraining climate sensitivity and evaluating model simulations1. The first quantitative global reconstruction of sea surface temperatures during the Last Glacial Maximum was developed by the Climate Long-Range Investigation, Mapping and Prediction (CLIMAP) project in the 1970s and 1980s (refs 2, 3). Since that time, several shortcomings of that earlier effort have become apparent4. Here we present an updated synthesis of sea surface temperatures during the Last Glacial Maximum, rigorously defined as the period between 23 and 19 thousand years before present, from the Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface (MARGO) project5. We integrate microfossil and geochemical reconstructions of surface temperatures and include assessments of the reliability of individual records. Our reconstruction reveals the presence of large longitudinal gradients in sea surface temperature in all of the ocean basins, in contrast to the simulations of the Last Glacial Maximum climate available at present6, 7.

Toward Information Infrastructure Studies: Ways of Knowing in a Networked Environment

Abstract: This article presents Information Infrastructure Studies, a research area that takes up some core issues in digital information and organization research. Infrastructure Studies simultaneously addresses the technical, social, and organizational aspects of the development, usage, and maintenance of infrastructures in local communities as well as global arenas. While infrastructure is understood as a broad category referring to a variety of pervasive, enabling network resources such as railroad lines, plumbing and pipes, electrical power plants and wires, this article focuses on information infrastructure, such as computational services and help desks, or federating activities such as scientific data repositories and archives spanning the multiple disciplines needed to address such issues as climate warming and the biodiversity crisis. These are elements associated with the internet and, frequently today, associated with cyberinfrastructure or e-science endeavors. We argue that a theoretical understanding of infrastructure provides the context for needed dialogue between design, use, and sustainability of internet-based infrastructure services. This article outlines a research area and outlines overarching themes of Infrastructure Studies. Part one of the paper presents definitions for infrastructure and cyberinfrastructure, reviewing salient previous work. Part two portrays key ideas from infrastructure studies (knowledge work, social and political values, new forms of sociality, etc.). In closing, the character of the field today is considered.

On the Development of Harmonious and Obsessive Passion : The Role of Autonomy Support, Activity Specialization, and Identification With the Activity

Abstract: Recent research (Vallerand et al., 2003) has supported the existence of two types of passion for activities: a harmonious and an obsessive passion. The purpose of this investigation was to study the processes likely to lead to the development of passion. Three studies using correlational and short-term longitudinal designs with varied populations ranging from beginners to experts reveal that identification with the activity, activity specialization, parents' activity valuation, and autonomy support predict the development of passion. Furthermore, results show that children and teenagers whose environment supports their autonomy are more likely to develop a harmonious passion than an obsessive one. Conversely, children and teenagers who highly value activity specialization, who rely heavily on their activity for self-definition, and whose parents highly value the activity are more likely to develop an obsessive passion.

Comparing Bibliometric Statistics Obtained from the Web of Science and Scopus

Abstract: For more than 40 years, the Institute for Scientific Information (ISI, now part of Thomson Reuters) produced the only available bibliographic databases from which bibliometricians could compile large-scale bibliometric indicators. ISI's citation indexes, now regrouped under the Web of Science (WoS), were the major sources of bibliometric data until 2004, when Scopus was launched by the publisher Reed Elsevier. For those who perform bibliometric analyses and comparisons of countries or institutions, the existence of these two major databases raises the important question of the comparability and stability of statistics obtained from different data sources. This paper uses macro-level bibliometric indicators to compare results obtained from the WoS and Scopus. It shows that the correlations between the measures obtained with both databases for the number of papers and the number of citations received by countries, as well as for their ranks, are extremely high (R2 > .99). There is also a very high correlation when countries' papers are broken down by field. The paper thus provides evidence that indicators of scientific production and citations at the country level are stable and largely independent of the database.

Antitumour activity of ANG1005, a conjugate between paclitaxel and the new brain delivery vector Angiopep-2.

Abstract: Regina A, Demeule M, Che C, Lavallee I, Poirier J, Gabathuler R, Beliveau R, Castaigne JP. BACKGROUND AND PURPOSE : Paclitaxel is highly efficacious in the treatment of breast, head and neck, non-small cell lung cancers and ovarian carcinoma. For malignant gliomas, paclitaxel is prevented from reaching its target by the presence of the efflux pump P-glycoprotein (P-gp) at the blood-brain barrier. We investigated the utilization of a new drug delivery system to increase brain delivery of (...)

Comparing bibliometric statistics obtained from the Web of Science and Scopus

Abstract: For more than 40 years, the Institute for Scientific Information (ISI, now part of Thomson Reuters) produced the only available bibliographic databases from which bibliometricians could compile large-scale bibliometric indicators. ISI's citation indexes, now regrouped under the Web of Science (WoS), were the major sources of bibliometric data until 2004, when Scopus was launched by the publisher Reed Elsevier. For those who perform bibliometric analyses and comparisons of countries or institutions, the existence of these two major databases raises the important question of the comparability and stability of statistics obtained from different data sources. This paper uses macrolevel bibliometric indicators to compare results obtained from the WoS and Scopus. It shows that the correlations between the measures obtained with both databases for the number of papers and the number of citations received by countries, as well as for their ranks, are extremely high (R2 a .99). There is also a very high correlation when countries' papers are broken down by field. The paper thus provides evidence that indicators of scientific production and citations at the country level are stable and largely independent of the database. © 2009 Wiley Periodicals, Inc.

Forest management is driving the eastern North American boreal forest outside its natural range of variability

Abstract: Fire is fundamental to the natural dynamics of the North American boreal forest. It is therefore often suggested that the impacts of anthropogenic disturbances (eg logging) on a managed landscape are attenuated if the patterns and processes created by these events resemble those of natural disturbances (eg fire). To provide forest management guidelines, we investigate the long-term variability in the mean fire interval (MFI) of a boreal landscape in eastern North America, as reconstructed from lacustrine (lake-associated) sedimentary charcoal. We translate the natural variability in MFI into a range of landscape age structures, using a simple modeling approach. Although using the array of possible forest age structures provides managers with some flexibility, an assessment of the current state of the landscape suggests that logging has already caused a shift in the age-class distribution toward a stronger representation of young stands with a concurrent decrease in old-growth stands. Logging is indeed quickly forcing the studied landscape outside of its long-term natural range of variability, implying that substantial changes in management practices are required, if we collectively decide to maintain these fundamental attributes of the boreal forest.

Intelligent Freight Transportation Systems : Assessment and the Contribution of Operations Research

Abstract: While it is certainly too early to make a definitive assessment of the effectiveness of Intelligent Transportation Systems (ITS), it is not to take stock of what has been achieved and to think about what could be achieved in the near future. In our opinion, ITS developments have been up to now largely hardware-driven and have led to the introduction of many sophisticated technologies in the transportation arena, while the development of the software component of ITS, models and decision-support systems in particular, is lagging behind. To reach the full potential of ITS, one must thus address the challenge of making the most intelligent usage possible of the hardware that is being deployed and the huge wealth of data it provides. We believe that transportation planning and management disciplines, operations research in particular, have a key role to play with respect to this challenge. The paper focuses on Freight ITS: Commercial Vehicle Operations and Advanced Fleet Management Systems, City Logistics, and electronic business. The paper reviews main issues, technological challenges, and achievements, and illustrates how the introduction of better operations research-based decision-support software could very significantly improve the ultimate performance of Freight ITS.

Natural Language Understanding

Abstract: I focus on three characteristics of natural language understanding systems that incorporate the properties that make humans able to understand language naturally. The first characteristic of such systems is that they handle recursion. A second property of these systems is that they process abstract hierarchical structures, and they are not limited to the processing of strings of characters or keywords. A third characteristic is that they connect physical forms and interpretations.

History of the journal impact factor: contingencies and consequences

Abstract: This paper examines the genesis of journal impact measures and how their evolution culminated in the journal impact factor (JIF) produced by the Institute for Scientific Information. The paper shows how the various building blocks of the dominant JIF (published in the Journal Citation Report - JCR) came into being. The paper argues that these building blocks were all constructed fairly arbitrarily or for different purposes than those that govern the contemporary use of the JIF. The results are a faulty method, widely open to manipulation by journal editors and misuse by uncritical parties. The discussion examines some solution offered to the bibliometrics and scientific communities considering the wide use of this indicator at present.

Joint seismic, geodynamic and mineral physical constraints on three-dimensional mantle heterogeneity: Implications for the relative importance of thermal versus compositional heterogeneity

Abstract: SUMMARY The joint interpretation of seismic and geodynamic data requires mineral physical parameters linking seismic velocity to density perturbations in the Earth’s mantle. The most common approach is to link velocity and density through relative scaling or conversion factors: R ρ/s = dlnρ/dlnV S. However, the range of possible R ρ/s values remains large even when only considering thermal effects. We directly test the validity of several proposed depthdependent conversion profiles developed from mineral physics studies for thermally-varying properties of mantle materials. The tests are conducted by simultaneously inverting shear wave traveltime data and a diverse suite of convection-related constraints interpreted with viscous-flow response functions of the mantle. These geodynamic constraints are represented by surface spherical harmonic basis functions (up to harmonic degree 16) and they consist of the global free-air gravity field, tectonic plate divergences, dynamic surface topography and the excess ellipticity of the core-mantle boundary (CMB). The tests yield an optimum 1-D thermal R ρ/s profile that is generally compatible with all considered data, with the exception of the dynamic surface topography that is most sensitive to the shallow upper mantle. This result is not surprising given that cratonic roots are known to be compositionally-distinct from the surrounding ambient mantle. Moreover, it is expected that the temperature-dependence of the thermal R ρ/s in the upper mantle is significant due to the temperature-dependence of seismic attenuation or Q. Therefore, a simple 1-D density–velocity relationship is insufficient. To address this problem, we obtained independent estimates of the first-order correction factors to the selected R ρ/s profile within the cratonic roots and in the ambient (thermal) upper mantle. These correction factors, defined as ∂R ρ/s/∂lnV S, are highly negative within the cratons signifying considerable compositional buoyancy. This result confirms that the negative buoyancy associated with the low temperatures in the cratons is significantly counteracted by the composition-induced positive buoyancy resulting in near-neutral buoyancy of the cratonic roots. Within the ambient upper mantle, the correction factors are found to be positive which is consistent with the expected behaviour of the R ρ/s relationship in thermally-varying upper-mantle material. We obtain a significantly greater reconciliation of the global gravity anomalies and dynamic surface topography when applying these laterally-varying corrections compared to a simple 1-D R ρ/s relationship. Inversion for a fully 3-D R ρ/s relationship reveals secondary effects including additional compositional variation within the cratonic roots and the deep-mantle superplume structures. We estimate the relative magnitude of the thermal and compositional (non-thermal) contributions to mantle density anomalies and conclude that thermal effects dominate shear wave and density heterogeneity throughout the non-cratonic mantle. We also demonstrate the potential pitfalls of scaling a purely seismically-derived model to obtain density rather than performing a true joint inversion to obtain velocity and density simultaneously.

Male personality, life‐history strategies and reproductive success in a promiscuous mammal

Abstract: Recent theoretical work suggests that personality is a component of life history, but links between personality and either age-dependent reproductive success or life-history strategy are yet to be established. Using quantitative genetic analyses on a long-term pedigree we estimated indices of boldness and docility for 105 bighorn sheep rams (Ovis canadensis), born between 1983 and 1999, and compared these indices to their reproductive history from 2 years of age until death. Docility and boldness were highly heritable and negatively genetically correlated. Docile and bold rams survived longer than indocile and shy rams. Docility and boldness had a weak negative effect on reproductive success early in life, but a strong positive effect on older rams. Our findings highlight an important role of personality on reproductive success and suggest that personality could be an important component of life-history strategy.

Prevalence of childhood sexual abuse and timing of disclosure in a representative sample of adults from Quebec.

Abstract: Objective: Our study sought to explore patterns of disclosure of child sexual abuse (CSA) in a sample of adult men and women. Method: A telephone survey conducted with a representative sample of adults (n = 804) from Quebec assessed the prevalence of CSA and disclosure patterns. Analyses were carried out to determine whether disclosure groups differed in terms of psychological distress and symptoms of posttraumatic stress, and a logistic regression was used to examine factors associated with prompt disclosure. Results: Prevalence of CSA was 22.1% for women and 9.7% for men. About 1 survivor out of 5 had never disclosed the abuse, with men more likely not to have told anyone, than women. Only 21.2% of adults reported prompt disclosure (within a month of the first abusive event), while 57.5% delayed disclosure (more than 5 years after the first episode). CSA victims who never disclosed the abuse and those who delayed disclosure were more likely to obtain scores of psychological distress and posttraumatic stress achieving clinical levels, compared with adults without a history of CSA. In the multivariate analysis, experiencing CSA involving a perpetrator outside the immediate family and being female were factors independently associated with prompt disclosure. Conclusion: A significant number of adult women and men reported experiencing CSA, and most victims attested to either not disclosing or significantly delaying abuse disclosure. Language: en

Codes and Automata

Abstract: Preface 1. Preliminaries 2. Codes 3. Prefix codes 4. Automata 5. Deciphering delay 6. Bifix codes 7. Circular codes 8. Factorizations of free monoids 9. Unambiguous monoids of relations 10. Synchronization 11. Groups of codes 12. Factorizations of cyclic groups 13. Densities 14. Polynomials of finite codes Solutions of exercises Appendix: Research problems References Index of notation Index.

Passion Does Make a Difference in People's Lives: A Look at Well-Being in Passionate and Non-Passionate Individuals

Abstract: The purpose of the present research was to examine the differences in well-being between passionate and non-passionate individuals of various age groups. The results of two studies (total n = 885) provided support for the hypothesis that being harmoniously passionate for an activity contributes significantly to both hedonic and eudaimonic well-being, while being obsessively passionate for an activity or having no passion at all does not contribute to well-being. Furthermore, results from Study 2 showed that only harmoniously passionate people experienced an increase in subjective vitality over a 1-year period compared to obsessively passionate and non-passionate people who did not differ from each other. These results also held true after controlling for the effect of age and gender. It would thus appear that passion does make a difference in people's lives, as long as such passion is harmonious in nature.

Fear avoidance and self-efficacy in relation to pain and sexual impairment in women with provoked vestibulodynia.

Abstract: Background Provoked vestibulodynia is believed to be the most frequent cause of vulvodynia in women of childbearing age, with prevalence rates of up to 12% in the general population. Despite this high prevalence and the fact that vestibulodynia impacts negatively on quality of life, in particular sexual functioning, there has been a paucity of sound research to elucidate the condition's etiology. More specifically, few studies have focused on the role of psychologic factors in the experience of vulvo-vaginal pain and associated sexual impairment. Objectives The present study aimed to determine the extent to which fear avoidance variables (catastrophizing, anxiety, fear of pain, hypervigilance) and self-efficacy differentially influenced changes in levels of induced and intercourse pain and also associated sexual dysfunction in these women. Methods Data were obtained from 75 vestibulodynia participants who completed a gynecologic examination, structured interview, and standardized questionnaires. Results The results of regression analyses revealed that higher catastrophizing, fear of pain, and hypervigilance in addition to lower self-efficacy together accounted for 15% of the variation in increased intercourse pain intensity. Among these, only catastrophizing contributed unique variance to intercourse pain. Results also showed that higher state anxiety and fear of pain (escape/avoidance) and also lower self-efficacy explained 22% of the variation in women's sexual impairment. However, only self-efficacy was found to be an independent correlate of sexual impairment. Conclusion Findings support a theoretical model of vestibulodynia as a pain disorder influenced among others by cognitive and affective factors.

Studying the relationship between low back pain and working postures among those who stand and those who sit most of the working day.

Abstract: A relationship between low back pain (LBP) and prolonged standing or prolonged sitting at work has not been clearly shown, despite its biological plausibility. Because sitting and standing postures vary as to duration and freedom to alternate postures, and standing postures vary as to mobility, associations between specific working postures and LBP were explored using multiple logistic regression. Associations between work factors and self-reported LBP during the previous 12 months that interfered with usual activities were examined among 4493 standing workers and 3237 sitting workers interviewed in the 1998 Quebec Health and Social Survey; 24.5% reported significant LBP. Since the same conditions can correspond to different physiological demands for sitting compared with standing workers, analyses were performed separately for the two groups. Standing without freedom to sit was associated with LBP. Different occupational physical and psychosocial factors were associated with LBP in sitting compared with standing populations.

Face gender and emotion expression: are angry women more like men?

Abstract: Certain features of facial appearance perceptually resemble expressive cues related to facial displays of emotion. We hypothesized that because expressive markers of anger (such as lowered eyebrows) overlap with perceptual markers of male sex, perceivers would identify androgynous angry faces as more likely to be a man than a woman (Study 1) and would be slower to classify an angry woman as a woman than an angry man as a man (Study 2). Conversely, we hypothesized that because perceptual features of fear (raised eyebrows) and happiness (a rounded smiling face) overlap with female sex markers, perceivers would be more likely to identify an androgynous face showing these emotions as a woman than as a man (Study 1) and would be slower to identify happy and fearful men as men than happy and fearful women as women (Study 2). The results of the two studies showed that happiness and fear expressions bias sex discrimination toward the female, whereas anger expressions bias sex perception toward the male.

Nitrogen dynamics at the sediment–water interface in shallow, sub-tropical Florida Bay: why denitrification efficiency may decrease with increased eutrophication

Abstract: Nitrogen (N) dynamics at the sediment–water interface were examined in four regions of Florida Bay to provide mechanistic information on the fate and effects of increased N inputs to shallow, subtropical, coastal environments Dissimilatory nitrate (NO3 −) reduction to ammonium (DNRA) was hypothesized to be a significant mechanism retaining bioreactive N in this warm, saline coastal ecosystem Nitrogen dynamics, phosphorus (P) fluxes, and sediment oxygen demand (SOD) were measured in north-central (Rankin Key; eutrophic), north-eastern (Duck Key; high N to P seston ratios), north-western (Murray Key; low N to P ratios), and central (Rabbit Key; typical central site) Florida Bay in August 2004, January 2005, and November 2006 Site water was passed over intact sediment cores, and changes in oxygen (O2), phosphate (o-PO4 3−), ammonium (NH4 +), NO3 −, nitrite (NO2 −), and N2 concentrations were measured, without and with addition of excess 15NO3 − or 15NH4 + to inflow water These incubations provided estimates of SOD, nutrient fluxes, N2 production, and potential DNRA rates Denitrification rates were lowest in summer, when SOD was highest DNRA rates and NH4 + fluxes were high in summer at the eutrophic Rankin site, when denitrification rates were low and almost no N2 came from added 15NO3 − Highest 15NH4 + accumulation, resulting from DNRA, occurred at Rabbit Key during a picocyanobacteria bloom in November 15NH4 + accumulation rates among the stations correlated with SOD in August and January, but not in November during the algal bloom These mechanistic results help explain why bioreactive N supply rates are sometimes high in Florida Bay and why denitrification efficiency may decrease with increased NO3 − inputs in sub-tropical coastal environments

A closer look at the relationship between affective commitment to supervisors and organizations and turnover

Abstract: We examined the relationships of affective organizational commitment and affective commitment to supervisors with turnover intentions and actual turnover, using three independent samples of employees. In Sample I (N = I72) and Sample 2 (N = I86), affective organizational commitment and affective commitment to supervisors were found to exert independent negative effects on turnover intentions. Moreover, in both samples, affective commitment to supervisors was more strongly related to turnover intentions when affective organizational commitment was low. In Sample 3 (N = 431), affective commitment to supervisors was the single significant predictor of actual turnover and interacted with affective organizational commitment such that its effect was stronger when affective organizational commitment was low. The implications of these findings for the understanding of the commitment―turnover relationship are discussed.