Showing papers by "Université du Québec à Montréal published in 2017"

Structure and Function of the Human Insula.

Abstract: The insular cortex, or "Island of Reil," is hidden deep within the lateral sulcus of the brain. Subdivisions within the insula have been identified on the basis of cytoarchitectonics, sulcal landmarks, and connectivity. Depending on the parcellation technique used, the insula can be divided into anywhere between 2 and 13 distinct subdivisions. The insula subserves a wide variety of functions in humans ranging from sensory and affective processing to high-level cognition. Here, we provide a concise summary of known structural and functional features of the human insular cortex with a focus on lesion case studies and recent neuroimaging evidence for considerable functional heterogeneity of this brain region.

Persistent effects of pre-Columbian plant domestication on Amazonian forest composition

Abstract: The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.

Synthesis and characterization of sulfophenyl-functionalized reduced graphene oxide sheets

Abstract: We report the modification of graphene oxide (GO) by thermal reduction to obtain reduced graphene oxide (RGO) and subsequent modification by sulfophenyl groups as well as the characterization of these materials by thermogravimetric analysis coupled with mass spectroscopy (TGA-MS) The chemical modification of RGO was carried out by the spontaneous reaction of RGO with in situ generated sulfophenyl diazonium ions The three different types of materials were also characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) The characteristic absorption band at 1034 and 1160 cm−1 in the FTIR spectrum of the sulfophenyl-modified RGO (SRGO), as well as Raman spectroscopy and TGA-MS data indicated that sulfophenyl groups were successfully grafted on RGO The presence of organic molecules at the SRGO surface was also demonstrated by elemental analysis, transmission electron microscopy, energy dispersive X-ray spectroscopy and XPS TGA data and elemental analysis results showed that the loading of sulfophenyl groups was about 12 wt% and UV-visible-near IR spectroscopy confirms the slight increase of the optical band gap of RGO after covalent grafting of sulfophenyl groups on its surface

Optimal Financial Knowledge and Wealth Inequality.

Abstract: We show that financial knowledge is a key determinant of wealth inequality in a stochastic life cycle model with endogenous financial knowledge accumulation, where financial knowledge enables individuals to better allocate lifetime resources in a world of uncertainty and imperfect insurance. Moreover, because of how the US social insurance system works, better-educated individuals have most to gain from investing in financial knowledge. Our parsimonious specification generates substantial wealth inequality relative to a one-asset saving model and one in which returns on wealth depend on portfolio composition alone. We estimate that 30–40 percent of retirement wealth inequality is accounted for by financial knowledge.

Spatial complementarity in tree crowns explains overyielding in species mixtures

Abstract: Deciphering the mechanisms that link biodiversity with ecosystem functions is critical to understanding the consequences of changes in biodiversity. The hypothesis that complementarity and selection effects drive relationships between biodiversity and ecosystem functions is well accepted, and an approach to statistically untangle the relative importance of these effects has been widely applied. In contrast, empirical demonstrations of the biological mechanisms that underlie these relationships remain rare. Here, on the basis of a field experiment with young trees, we provide evidence that one form of complementarity in plant communities-complementarity among crowns in canopy space-is a mechanism, related to light interception and use, that links biodiversity with ecosystem productivity. Stem biomass overyielding increased sharply in mixtures with greater crown complementarity. Inherent differences among species in crown architecture led to greater crown complementarity in functionally diverse species mixtures. Intraspecific variation, specifically neighbourhood-driven plasticity in crowns, further modified spatial complementarity and strengthened the positive relationship with overyielding-crown plasticity and inherent interspecific differences contributed near equally in explaining patterns of overyielding. We posit that crown complementarity is an important mechanism that may contribute to diversity-enhanced productivity in forests.

Leaf bacterial diversity mediates plant diversity and ecosystem function relationships

Abstract: Research on biodiversity and ecosystem functioning has demonstrated links between plant diversity and ecosystem functions such as productivity At other trophic levels, the plant microbiome has been shown to influence host plant fitness and function, and host-associated microbes have been proposed to influence ecosystem function through their role in defining the extended phenotype of host organisms However, the importance of the plant microbiome for ecosystem function has not been quantified in the context of the known importance of plant diversity and traits Here, using a tree biodiversity-ecosystem functioning experiment, we provide strong support for the hypothesis that leaf bacterial diversity is positively linked to ecosystem productivity, even after accounting for the role of plant diversity Our results also show that host species identity, functional identity and functional diversity are the main determinants of leaf bacterial community structure and diversity Our study provides evidence of a positive correlation between plant-associated microbial diversity and terrestrial ecosystem productivity, and a new mechanism by which models of biodiversity-ecosystem functioning relationships can be improved

Corpus Use in Language Learning: A Meta-Analysis.

Abstract: This study applied systematic meta-analytic procedures to summarize findings from experimental and quasi-experimental investigations into the effectiveness of using the tools and techniques of corpus linguistics for second language learning or use, here referred to as data-driven learning (DDL). Analysis of 64 separate studies representing 88 unique samples reporting sufficient data indicated that DDL approaches result in large overall effects for both control/experimental group comparisons (d = 0.95) and for pre/posttest designs (d = 1.50). Further investigation of moderator variables revealed that small effect sizes were generally tied to small sample sizes. Research has barely begun in some key areas, and durability/transfer of learning through delayed posttesting remains an area in need of further investigation. Although DDL research demonstrably improved over the period investigated, further changes in practice and reporting are recommended.

Biodiversity and ecosystem functioning relations in European forests depend on environmental context

Abstract: The importance of biodiversity in supporting ecosystem functioning is generally well accepted. However, most evidence comes from small-scale studies, and scaling-up patterns of biodiversity-ecosystem functioning (B-EF) remains challenging, in part because the importance of environmental factors in shaping B-EF relations is poorly understood. Using a forest research platform in which 26 ecosystem functions were measured along gradients of tree species richness in six regions across Europe, we investigated the extent and the potential drivers of context dependency of B-EF relations. Despite considerable variation in species richness effects across the continent, we found a tendency for stronger B-EF relations in drier climates as well as in areas with longer growing seasons and more functionally diverse tree species. The importance of water availability in driving context dependency suggests that as water limitation increases under climate change, biodiversity may become even more important to support high levels of functioning in European forests.

Climate, soil and plant functional types as drivers of global fine-root trait variation

Abstract: 1.Ecosystem functioning relies heavily on belowground processes, which are largely regulated by plant fine-roots and their functional traits. However, our knowledge of fine-root trait distribution relies to date on local- and regional-scale studies with limited numbers of species, growth forms and environmental variation. 2.We compiled a worldwide fine-root trait dataset, featuring 1115 species from contrasting climatic areas, phylogeny and growth forms to test a series of hypotheses pertaining to the influence of plant functional types, soil and climate variables, and the degree of manipulation of plant growing conditions on species fine-root trait variation. Most particularly, we tested the competing hypotheses that fine-root traits typical of faster return on investment would be most strongly associated with conditions of limiting versus favourable soil resource availability. We accounted for both data source and species phylogenetic relatedness. 3.We demonstrate that (1) Climate conditions promoting soil fertility relate negatively to fine-root traits favouring fast soil resource acquisition, with a particularly strong positive effect of temperature on fine-root diameter and negative effect on specific root length (SRL), and a negative effect of rainfall on root nitrogen concentration; (2) Soil bulk density strongly influences species fine-root morphology, by favouring thicker, denser fine-roots; (3) Fine-roots from herbaceous species are on average finer and have higher SRL than those of woody species, and N2-fixing capacity positively relates to root nitrogen; (4) Plants growing in pots have higher SRL than those grown in the field. 4.Synthesis. This study reveals both the large variation in fine-root traits encountered globally and the relevance of several key plant functional types and soil and climate variables for explaining a substantial part of this variation. Climate, particularly temperature, and plant functional types were the two strongest predictors of fine-root trait variation. High trait variation occurred at local scales, suggesting that wide-ranging belowground resource economics strategies are viable within most climatic areas and soil conditions.

Towards a universal model for carbon dioxide uptake by plants.

Abstract: Gross primary production (GPP)-the uptake of carbon dioxide (CO2) by leaves, and its conversion to sugars by photosynthesis-is the basis for life on land. Earth System Models (ESMs) incorporating the interactions of land ecosystems and climate are used to predict the future of the terrestrial sink for anthropogenic CO21 . ESMs require accurate representation of GPP. However, current ESMs disagree on how GPP responds to environmental variations 1,2 , suggesting a need for a more robust theoretical framework for modelling 3,4 . Here, we focus on a key quantity for GPP, the ratio of leaf internal to external CO2 (χ). χ is tightly regulated and depends on environmental conditions, but is represented empirically and incompletely in today's models. We show that a simple evolutionary optimality hypothesis 5,6 predicts specific quantitative dependencies of χ on temperature, vapour pressure deficit and elevation; and that these same dependencies emerge from an independent analysis of empirical χ values, derived from a worldwide dataset of >3,500 leaf stable carbon isotope measurements. A single global equation embodying these relationships then unifies the empirical light-use efficiency model 7 with the standard model of C3 photosynthesis 8 , and successfully predicts GPP measured at eddy-covariance flux sites. This success is notable given the equation's simplicity and broad applicability across biomes and plant functional types. It provides a theoretical underpinning for the analysis of plant functional coordination across species and emergent properties of ecosystems, and a potential basis for the reformulation of the controls of GPP in next-generation ESMs.

Perspective—A Guideline for Reporting Performance Metrics with Electrochemical Capacitors: From Electrode Materials to Full Devices

Abstract: Over the past decade, interest in electrochemical capacitors as an energy-storage technology has increased enormously, spurring the development and evaluation of a large number of new materials and device configurations. This perspective article aims to propose guidelines by which new materials and devices should be evaluated, and how resulting data should be reported with respect to critical metrics such as capacitance, energy and power.

The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project

Abstract: The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

Linked sustainability challenges and trade-offs among fisheries, aquaculture and agriculture.

Abstract: Fisheries and aquaculture make a crucial contribution to global food security, nutrition and livelihoods. However, the UN Sustainable Development Goals separate marine and terrestrial food production sectors and ecosystems. To sustainably meet increasing global demands for fish, the interlinkages among goals within and across fisheries, aquaculture and agriculture sectors must be recognized and addressed along with their changing nature. Here, we assess and highlight development challenges for fisheries-dependent countries based on analyses of interactions and trade-offs between goals focusing on food, biodiversity and climate change. We demonstrate that some countries are likely to face double jeopardies in both fisheries and agriculture sectors under climate change. The strategies to mitigate these risks will be context-dependent, and will need to directly address the trade-offs among Sustainable Development Goals, such as halting biodiversity loss and reducing poverty. Countries with low adaptive capacity but increasing demand for food require greater support and capacity building to transition towards reconciling trade-offs. Necessary actions are context-dependent and include effective governance, improved management and conservation, maximizing societal and environmental benefits from trade, increased equitability of distribution and innovation in food production, including continued development of low input and low impact aquaculture.

Effects of three global change drivers on terrestrial C:N:P stoichiometry: a global synthesis.

Abstract: Over the last few decades there has been an increasing number of controlled-manipulative experiments to investigate how plants and soils might respond to global change. These experiments typically examined the effects of each of three global change drivers (i.e. nitrogen (N) deposition, warming, and elevated CO2) on primary productivity and on the biogeochemistry of carbon (C), N and phosphorus (P) across different terrestrial ecosystems. Here we capitalize on this large amount of information by performing a comprehensive meta-analysis (>2000 case studies worldwide) to address how C:N:P stoichiometry of plants, soils and soil microbial biomass might respond to individual vs. combined effects of the three global change drivers. Our results show that (1) individual effects of N addition and elevated CO2 on C:N:P stoichiometry are stronger than warming, (2) combined effects of pairs of global change drivers (e.g., N addition + elevated CO2, warming + elevated CO2) on C:N:P stoichiometry were generally weaker than the individual effects of each of these drivers, (3) additive interactions (i.e. when combined effects are equal to or no significantly different from the sum of individual effects) were more common than synergistic or antagonistic interactions, (4) C:N:P stoichiometry of soil and soil microbial biomass shows high homeostasis under global change manipulations, and (5) C:N:P responses to global change are strongly affected by ecosystem type, local climate and experimental conditions. Our study is one of the first to compare individual vs. combined effects of the three global change drivers on terrestrial C:N:P ratios using a large set of data. To further improve our understanding of how ecosystems might respond to future global change, long-term ecosystem-scale studies testing multifactor effects on plants and soils are urgently required across different world regions. This article is protected by copyright. All rights reserved.

Hybrid MMSE Precoding and Combining Designs for mmWave Multiuser Systems

Abstract: Hybrid analog/digital precoding architectures are a low-complexity alternative for fully digital precoding in millimeter-wave (mmWave) MIMO wireless systems This is motivated by the reduction in the number of radio frequency and mixed signal hardware components Hybrid precoding involves a combination of analog and digital processing that enables both beamforming and spatial multiplexing gains in mmWave systems This paper develops hybrid analog/digital precoding and combining designs for mmWave multiuser systems, based on the mean-squared error (MSE) criteria In the first design with the analog combiners being determined at the users, the proposed hybrid minimum MSE (MMSE) precoder is realized by minimizing the sum-MSE of the data streams intended for the users In the second design, both the hybrid precoder and combiners are jointly designed in an iterative manner to minimize a weighted sum-MSE cost function By leveraging the sparse structure of mmWave channels, the MMSE precoding/combining design problems are then formulated as sparse reconstruction problems An orthogonal matching pursuit-based algorithm is then developed to determine the MMSE precoder and combiners Simulation results show the performance advantages of the proposed precoding/combining designs in various system settings

Why phylogenies do not always predict ecological differences

Abstract: The merger of phylogenies with ecology has given rise to the field of “community phylogenetics” predicated on the assumption that ecological differences among species can be estimated from phylogenetic relationships (the phylogenetic distance/ecological difference, PDED, hypothesis). A number of studies have failed to find strong support for this assumption, thus challenging the utility of phylogenetic approaches. This gap might highlight the fact that the PDED relationship is not useful for community assembly, but it is difficult to know because the lack of a relationship might also be due to a number of biological or methodological reasons, including inappropriate phylogenies, skewed distributions of phylogenetic distances, the lack of consideration of models of trait evolution, or the absence of sufficient niche space in experimental and observational venues. Each of these limitations, separately or combined, may confound recent experimental or observational results that examine relationships between phylogenetic distance and ecological differences. Notably, common evolutionary models can support alternative conclusions about the relationship between evolutionary distances and ecological differences than typically assumed and can change interpretations of community-based phylogenetic analyses. Here we review a number of issues that may lead to confounded effects in community phylogenetic analyses. In light of these potential pitfalls, we provide a number of guidelines for researchers to follow and stress that they need to address methodological shortcomings before concluding that ecological differences are unrelated to phylogenetic distances. This article is protected by copyright. All rights reserved.

Past and future carbon sequestration benefits of China’s grain for green program

Abstract: Carbon sequestration through ecological restoration programs is an increasingly important option to reduce the rise of atmospheric carbon dioxide concentration China’s Grain for Green Program (GGP) is likely the largest centrally organized land-use change program in human history and yet its carbon sequestration benefit has yet to be systematically assessed Here we used seven empirical/statistical equations of forest biomass carbon sequestration and five soil carbon change models to estimate the total and decadal carbon sequestration potentials of the GGP during 1999–2050, including changes in four carbon pools: aboveground biomass, roots, forest floor and soil organic carbon The results showed that the total carbon stock in the GGP-affected areas was 682 Tg C in 2010 and the accumulative carbon sink estimates induced by the GGP would be 1697, 2635, 3438 and 4115 Tg C for 2020, 2030, 2040 and 2050, respectively Overall, the carbon sequestration capacity of the GGP can offset about 3%–5% of China’s annual carbon emissions (calculated using 2010 emissions) and about 1% of the global carbon emissions Afforestation by the GGP contributed about 25% of biomass carbon sinks in global carbon sequestration in 2000–2010 The results suggest that large-scale ecological restoration programs such as afforestation and reforestation could help to enhance global carbon sinks, which may shed new light on the carbon sequestration benefits of such programs in China and also in other regions

Global wetland contribution to 2000–2012 atmospheric methane growth rate dynamics

Abstract: Increasing atmospheric methane (CH4) concentrations have contributed to approximately 20% of anthropogenic climate change. Despite the importance of CH4 as a greenhouse gas, its atmospheric growth rate and dynamics over the past two decades, which include a stabilization period (1999–2006), followed by renewed growth starting in 2007, remain poorly understood. We provide an updated estimate of CH4 emissions from wetlands, the largest natural global CH4 source, for 2000–2012 using an ensemble of biogeochemical models constrained with remote sensing surface inundation and inventory-based wetland area data. Between 2000–2012, boreal wetland CH4 emissions increased by 1.2 Tg yr−1 (−0.2–3.5 Tg yr−1), tropical emissions decreased by 0.9 Tg yr−1 (−3.2−1.1 Tg yr−1), yet globally, emissions remained unchanged at 184 ± 22 Tg yr−1. Changing air temperature was responsible for increasing high-latitude emissions whereas declines in low-latitude wetland area decreased tropical emissions; both dynamics are consistent with features of predicted centennial-scale climate change impacts on wetland CH4 emissions. Despite uncertainties in wetland area mapping, our study shows that global wetland CH4 emissions have not contributed significantly to the period of renewed atmospheric CH4 growth, and is consistent with findings from studies that indicate some combination of increasing fossil fuel and agriculture-related CH4 emissions, and a decrease in the atmospheric oxidative sink.

Influence of multiple global change drivers on terrestrial carbon storage: additive effects are common

Abstract: The interactive effects of multiple global change drivers on terrestrial carbon (C) storage remain poorly understood. Here, we synthesise data from 633 published studies to show how the interactive effects of multiple drivers are generally additive (i.e. not differing from the sum of their individual effects) rather than synergistic or antagonistic. We further show that (1) elevated CO2 , warming, N addition, P addition and increased rainfall, all exerted positive individual effects on plant C pools at both single-plant and plant-community levels; (2) plant C pool responses to individual or combined effects of multiple drivers are seldom scale-dependent (i.e. not differing from single-plant to plant-community levels) and (3) soil and microbial biomass C pools are significantly less sensitive than plant C pools to individual or combined effects. We provide a quantitative basis for integrating additive effects of multiple global change drivers into future assessments of the C storage ability of terrestrial ecosystems.

Cross continental increase in methane ebullition under climate change

Abstract: Methane (CH4) strongly contributes to observed global warming. As natural CH4 emissions mainly originate from wet ecosystems, it is important to unravel how climate change may affect these emissions. This is especially true for ebullition (bubble flux from sediments), a pathway that has long been underestimated but generally dominates emissions. Here we show a remarkably strong relationship between CH4 ebullition and temperature across a wide range of freshwater ecosystems on different continents using multi-seasonal CH4 ebullition data from the literature. As these temperature–ebullition relationships may have been affected by seasonal variation in organic matter availability, we also conducted a controlled year-round mesocosm experiment. Here 4 °C warming led to 51% higher total annual CH4 ebullition, while diffusion was not affected. Our combined findings suggest that global warming will strongly enhance freshwater CH4 emissions through a disproportional increase in ebullition (6–20% per 1 °C increase), contributing to global warming.

The servant leadership advantage: When perceiving low differentiation in leader-member relationship quality influences team cohesion, team task performance and service OCB

Abstract: How does servant leaders' unique ability to place each follower's needs above their own influence relationships between followers and impact their collective performance? In a study that integrates principles of servant leadership with the social comparison theoretical framework, we tested a group-level model to examine how servant leadership induces low perceived differentiation in leader-member relationship quality (perceived LMX differentiation) within a group, which strengthens team cohesion and in turn positively influences team task performance and service-oriented organizational citizenship behaviors (service OCB). Our sample comprised 229 employees nested in 67 work teams. Structural equation modeling results indicate that servant leadership significantly predicts low perceived LMX differentiation; perceived LMX differentiation is strongly related to team cohesion such that the lower the perceived differentiation, the stronger the team's cohesiveness. And, team cohesion is also strongly related to both the team's task performance and service OCB. Perceived LMX differentiation and team cohesion mediate the effect of servant leadership on both team task performance and service OCB.

Visible‐Light‐Initiated Manganese Catalysis for C−H Alkylation of Heteroarenes: Applications and Mechanistic Studies

Abstract: A visible-light-driven Minisci protocol that employs an inexpensive earth-abundant metal catalyst, decacarbonyldimanganese Mn2 (CO)10 , to generate alkyl radicals from alkyl iodides has been developed. This Minisci protocol is compatible with a wide array of sensitive functional groups, including oxetanes, sugar moieties, azetidines, tert-butyl carbamates (Boc-group), cyclobutanes, and spirocycles. The robustness of this protocol is demonstrated on the late-stage functionalization of complex nitrogen-containing drugs. Photophysical and DFT studies indicate a light-initiated chain reaction mechanism propagated by . Mn(CO)5 . The rate-limiting step is the iodine abstraction from an alkyl iodide by . Mn(CO)5 .

Obsessive Passion: A Compensatory Response to Unsatisfied Needs

Abstract: The present research investigated the role of two sources of psychological need satisfaction (inside and outside a passionate activity) as determinants of harmonious (HP) and obsessive (OP) passion. Four studies were carried out with different samples of young and middle-aged adults (e.g., athletes, musicians; total N = 648). Different research designs (cross-sectional, mixed, longitudinal) were also used. Results showed that only a rigid engagement in a passionate activity (OP) was predicted by low levels of need satisfaction outside the passionate activity (in an important life context or in life in general), whereas both OP and a more favorable and balanced type of passion, HP were positively predicted by need satisfaction inside the passionate activity. Further, OP led to negative outcomes, and HP predicted positive outcomes. These results suggest that OP may represent a form of compensatory striving for psychological need satisfaction. It appears important to consider two distinct sources of need satisfaction, inside and outside the passionate activity, when investigating determinants of optimal and less optimal forms of activity engagement.

Financial Literacy and Retirement Planning in Canada

Abstract: In this paper, we draw on internationally comparable survey evidence on financial literacy and retirement planning in Canada to investigate how financially literate Canadians are and how financial literacy is linked to retirement planning. We find that 42% of respondents are able to correctly answer three simple questions measuring knowledge of interest compounding, inflation, and risk diversification. This is consistent with evidence from other countries, and Canadians perform relatively well in comparison with Americans but worse than individuals in other countries, such as Germany. Among Canadian respondents, the young and the old, women, minorities, and those with lower educational attainment do worse, a pattern that has been consistently found in other countries as well. Retirement planning is strongly associated with financial literacy; those who responded correctly to all three financial literacy questions are 10 percentage points more likely to have retirement savings.

A conceptual model of mathematical reasoning for school mathematics

Abstract: The development of students’ mathematical reasoning (MR) is a goal of several curricula and an essential element of the culture of the mathematics education research community. But what mathematical reasoning consists of is not always clear; it is generally assumed that everyone has a sense of what it is. Wanting to clarify the elements of MR, this research project aimed to qualify it from a theoretical perspective, with an elaboration that would not only indicate its ways of being thought about and espoused but also serve as a tool for reflection and thereby contribute to the further evolution of the cultures of the teaching and research communities in mathematics education. To achieve such an elaboration, a literature search based on anasynthesis (Legendre, 2005) was undertaken. From the analysis of the mathematics education research literature on MR and taking a commognitive perspective (Sfard, 2008), the synthesis that was carried out led to conceptualizing a model of mathematical reasoning. This model, which is herein described, is constituted of two main aspects: a structural aspect and a process aspect, both of which are needed to capture the central characteristics of MR.

Interventions for obtaining and maintaining employment in adults with severe mental illness, a network meta‐analysis

Abstract: Background People with severe mental illness show high rates of unemployment and work disability, however, they often have a desire to participate in employment. People with severe mental illness used to be placed in sheltered employment or were enrolled in prevocational training to facilitate transition to a competitive job. Now, there are also interventions focusing on rapid search for a competitive job, with ongoing support to keep the job, known as supported employment. Recently, there has been a growing interest in combining supported employment with other prevocational or psychiatric interventions. Objectives To assess the comparative effectiveness of various types of vocational rehabilitation interventions and to rank these interventions according to their effectiveness to facilitate competitive employment in adults with severe mental illness. Search methods In November 2016 we searched CENTRAL, MEDLINE, Embase, PsychINFO, and CINAHL, and reference lists of articles for randomised controlled trials and systematic reviews. We identified systematic reviews from which to extract randomised controlled trials. Selection criteria We included randomised controlled trials and cluster-randomised controlled trials evaluating the effect of interventions on obtaining competitive employment for adults with severe mental illness. We included trials with competitive employment outcomes. The main intervention groups were prevocational training programmes, transitional employment interventions, supported employment, supported employment augmented with other specific interventions, and psychiatric care only. Data collection and analysis Two authors independently identified trials, performed data extraction, including adverse events, and assessed trial quality. We performed direct meta-analyses and a network meta-analysis including measurements of the surface under the cumulative ranking curve (SUCRA). We assessed the quality of the evidence for outcomes within the network meta-analysis according to GRADE. Main results We included 48 randomised controlled trials involving 8743 participants. Of these, 30 studied supported employment, 13 augmented supported employment, 17 prevocational training, and 6 transitional employment. Psychiatric care only was the control condition in 13 studies. Direct comparison meta-analysis of obtaining competitive employment We could include 18 trials with short-term follow-up in a direct meta-analysis (N = 2291) of the following comparisons. Supported employment was more effective than prevocational training (RR 2.52, 95% CI 1.21 to 5.24) and transitional employment (RR 3.49, 95% CI 1.77 to 6.89) and prevocational training was more effective than psychiatric care only (RR 8.96, 95% CI 1.77 to 45.51) in obtaining competitive employment. For the long-term follow-up direct meta-analysis, we could include 22 trials (N = 5233). Augmented supported employment (RR 4.32, 95% CI 1.49 to 12.48), supported employment (RR 1.51, 95% CI 1.36 to 1.68) and prevocational training (RR 2.19, 95% CI 1.07 to 4.46) were more effective than psychiatric care only. Augmented supported employment was more effective than supported employment (RR 1.94, 95% CI 1.03 to 3.65), transitional employment (RR 2.45, 95% CI 1.69 to 3.55) and prevocational training (RR 5.42, 95% CI 1.08 to 27.11). Supported employment was more effective than transitional employment (RR 3.28, 95% CI 2.13 to 5.04) and prevocational training (RR 2.31, 95% CI 1.85 to 2.89). Network meta-analysis of obtaining competitive employment We could include 22 trials with long-term follow-up in a network meta-analysis. Augmented supported employment was the most effective intervention versus psychiatric care only in obtaining competitive employment (RR 3.81, 95% CI 1.99 to 7.31, SUCRA 98.5, moderate-quality evidence), followed by supported employment (RR 2.72 95% CI 1.55 to 4.76; SUCRA 76.5, low-quality evidence). Prevocational training (RR 1.26, 95% CI 0.73 to 2.19; SUCRA 40.3, very low-quality evidence) and transitional employment were not considerably different from psychiatric care only (RR 1.00,95% CI 0.51 to 1.96; SUCRA 17.2, low-quality evidence) in achieving competitive employment, but prevocational training stood out in the SUCRA value and rank. Augmented supported employment was slightly better than supported employment, but not significantly (RR 1.40, 95% CI 0.92 to 2.14). The SUCRA value and mean rank were higher for augmented supported employment. The results of the network meta-analysis of the intervention subgroups favoured augmented supported employment interventions, but also cognitive training. However, supported employment augmented with symptom-related skills training showed the best results (RR compared to psychiatric care only 3.61 with 95% CI 1.03 to 12.63, SUCRA 80.3). We graded the quality of the evidence of the network ranking as very low because of potential risk of bias in the included studies, inconsistency and publication bias. Direct meta-analysis of maintaining competitive employment Based on the direct meta-analysis of the short-term follow-up of maintaining employment, supported employment was more effective than: psychiatric care only, transitional employment, prevocational training, and augmented supported employment. In the long-term follow-up direct meta-analysis, augmented supported employment was more effective than prevocational training (MD 22.79 weeks, 95% CI 15.96 to 29.62) and supported employment (MD 10.09, 95% CI 0.32 to 19.85) in maintaining competitive employment. Participants receiving supported employment worked more weeks than those receiving transitional employment (MD 17.36, 95% CI 11.53 to 23.18) or prevocational training (MD 11.56, 95% CI 5.99 to 17.13). We did not find differences between interventions in the risk of dropouts or hospital admissions. Authors' conclusions Supported employment and augmented supported employment were the most effective interventions for people with severe mental illness in terms of obtaining and maintaining employment, based on both the direct comparison analysis and the network meta-analysis, without increasing the risk of adverse events. These results are based on moderate- to low-quality evidence, meaning that future studies with lower risk of bias could change these results. Augmented supported employment may be slightly more effective compared to supported employment alone. However, this difference was small, based on the direct comparison analysis, and further decreased with the network meta-analysis meaning that this difference should be interpreted cautiously. More studies on maintaining competitive employment are needed to get a better understanding of whether the costs and efforts are worthwhile in the long term for both the individual and society.