Beyond ecosystem modeling: A roadmap to community cyberinfrastructure for ecological data‐model integration

In an era of rapid global change, our ability to understand and predict Earth's natural systems is lagging behind our ability to monitor and measure changes in the biosphere. Bottlenecks to informing models with observations have reduced our capacity to fully exploit the growing volume and variety of available data. Here, we take a critical look at the information infrastructure that connects ecosystem modeling and measurement efforts, and propose a roadmap to community cyberinfrastructure development that can reduce the divisions between empirical research and modeling and accelerate the pace of discovery. A new era of data‐model integration requires investment in accessible, scalable, and transparent tools that integrate the expertise of the whole community, including both modelers and empiricists. This roadmap focuses on five key opportunities for community tools: the underlying foundations of community cyberinfrastructure; data ingest; calibration of models to data; model‐data benchmarking; and data assimilation and ecological forecasting. This community‐driven approach is a key to meeting the pressing needs of science and society in the 21st century.     

Elevated temperature and periodic water stress alter growth and quality of common milkweed (<Emphasis Type="Italic">Asclepias syriaca</Emphasis>) and monarch (<Emphasis Type="Italic">Danaus plexippus</Emphasis>) larval performance

In this study, we examined the independent and interactive effects of temperature and water availability on the growth and foliar traits of common milkweed (Asclepias syriaca) and performance of a specialist herbivore, larvae of the monarch butterfly (Danaus plexippus). Milkweed from multiple population sources collected across a latitudinal gradient in Wisconsin, USA, were grown under all combinations of ambient or elevated temperature and the presence or absence of periodic water stress. Elevated temperature marginally increased, while water stress decreased plant growth. Milkweed from more northerly latitudes experienced larger growth responses to elevated temperature and were more resistant to water stress, especially under higher temperatures. Elevated temperature and water stress also altered milkweed composite foliar trait profiles. Elevated temperature generally increased leaf nitrogen and structural compounds, and decreased leaf mass per area. Water stress also elevated foliar nitrogen, but reduced defensive traits. Monarch larvae performed well on milkweed under elevated temperature and water stress, but gained the most mass on plants exposed to both treatments in combination. Our findings suggest that milkweed populations from more northerly latitudes in the upper Midwest may benefit more from rising temperatures than those in southerly locations, but that these beneficial effects depend on water availability. Monarch larvae grew larger on plants from all experimental treatments relative to ambient condition controls, indicating that future changes in milkweed presence on the landscape will likely influence monarch populations more than the effects of future changes in plant quality on larval performance.     

Vegetation demographics in Earth System Models: A review of progress and priorities

Numerous current efforts seek to improve the representation of ecosystem ecology and vegetation demographic processes within Earth System Models (ESMs). These developments are widely viewed as an important step in developing greater realism in predictions of future ecosystem states and fluxes. Increased realism, however, leads to increased model complexity, with new features raising a suite of ecological questions that require empirical constraints. Here, we review the developments that permit the representation of plant demographics in ESMs, and identify issues raised by these developments that highlight important gaps in ecological understanding. These issues inevitably translate into uncertainty in model projections but also allow models to be applied to new processes and questions concerning the dynamics of real‐world ecosystems. We argue that stronger and more innovative connections to data, across the range of scales considered, are required to address these gaps in understanding. The development of first‐generation land surface models as a unifying framework for ecophysiological understanding stimulated much research into plant physiological traits and gas exchange. Constraining predictions at ecologically relevant spatial and temporal scales will require a similar investment of effort and intensified inter‐disciplinary communication.     

Optimal control of the chemotherapy of HIV

 Using an existing ordinary differential equation model which describes the interaction of the immune system with the human immunodeficiency virus (HIV), we introduce chemotherapy in an early treatment setting through a dynamic treatment and then solve for an optimal chemotherapy strategy. The control represents the percentage of effect the chemotherapy has on the viral production. Using an objective function based on a combination of maximizing benefit based on T cell counts and minimizing the systemic cost of chemotherapy (based on high drug dose/strength), we solve for the optimal control in the optimality system composed of four ordinary differential equations and four adjoint ordinary differential equations. Received 5 July 1995; received in revised form 3 June 1996     

Antiviral action of membranotropic compounds modified by adamantane and norbornene pharmacophores exerted on different HIV-1 strains

The anti-HIV activity of new membranotropic compounds, i.e. of the polycarboxylate matrix and of its derivatives modified by adamantane and norbonene, was studied in respect of HIV-1 strains, whose tropicity to coreceptors CCR5 and CXCR4 was different, as well as in respect of HIV-1 variants resistant to azidothymidine (AZT) in a continuous culture of human lymphoid cells (MT-4) and in mononuclear cells of peripheral blood from healthy donors. Testing of complex compounds in a culture of infected MT-4 human lymphoid cells showed an effective inhibition of viral reproduction of LAV.04 (CXCR4-tropic variant) and of HIV11(EVK) as well as AZT-resistant variants. The studied pharmacophores-modified compounds displayed, in infection of the primary culture of human mononuclear cells of the HIV-1 R5 and X4 strains, a notable antiviral activity with their HIV efficiency significantly exceeding the one of the original matrix.     

Childhood aggression, withdrawal and likeability, and the use of health care later: a longitudinal study

Background:

Literature suggests that early patterns of aggressive behaviour in both girls and boys are predictive of a variety of health risks in adulthood. However, longitudinal examination of the predictive links between childhood aggression, negative physical health outcomes in adulthood and overall use of health care has not been done. We looked at use of health care and a variety of physical health outcomes in adulthood to extend the current body of knowledge regarding the long-term negative sequelae of childhood aggression.

Methods:

Participants of the Concordia Longitudinal Risk Project were eligible for the current study if they had received medical care in the province of Quebec between 1992 and 2006, and if we were able to retrieve their medical and education records. Our primary outcome was use of the health care system, as determined using records from the Régie de l’assurance maladie du Québec and the Ministère de la santé et des services sociaux. Our controlled variables were socioeconomic status of the neighbourhood in which participants lived in 1986 and level of education. We used hierarchical multiple regression to explore the association between childhood behaviour and physical health in adulthood.

Results:

During the 15-year period studied, childhood agression corresponded to an increase in medical visits (8.1% per 1 standard deviation increase in agression), and injuries (10.7%) or lifestyle-related illnesses (44.2%), visits to specialists (6.2%) and visits to emergency departments (12.4%). We saw a positive relation between social withdrawal during childhood and government-funded visits to dentists. Peer-rated likeability during childhood showed negative relations with use of health care (overall), medical visits due to injuries and government-funded visits to dentists.

Interpretation:

Childhood aggression is a health risk that should be considered when designing interventions to improve public health and diminish the costs of medical services, particularly when considering interventions targeting children and families.Predicting the use of health services among adults is gaining importance in Canada and elsewhere. As health care budgets decrease and the Canadian population ages, it is important to identify and understand the predictors of poor health in adulthood, as well as the protective factors that could lead to fewer medical interventions being needed.A developing body of literature is beginning to show that, in addition to genetic and physiologic factors, personality and behaviour influence lifetime health trajectories and outcomes. There are several reasons to believe that aggressive behaviour, starting in childhood, may be a possible risk factor for a number of health problems and increased use of health services later in life. Childhood aggression has been shown to predict such health risks as not completing high school,¹ teen pregnancy and single motherhood,² poverty,^3,4 engaging in high-risk and/or unprotected sex,^5,6 and dangerous driving.^6,7Government medical records and data on the use of health services drawn from a prospective longitudinal study provide a unique opportunity to examine the role of early childhood behaviour as it relates to health outcomes in adulthood. Research from the Concordia Longitudinal Risk Project using these types of data has shown that childhood aggression is predictive of overall use of health services, medical visits due to injuries and medical visits due to lifestyle-related illnesses.^8–10 However, previous studies have only looked at a limited number of predictors of health and indicators of service use. Our goal was to extend previous research by including records on service use from a greater number of years in addition to a new predictor — the level of poverty of the neighbourhood in which participants spent their late adolescences and young adulthoods. This new predictor is an indicator of both socioeconomic status and the environmental influences that participants may have been exposed to during the early, formative years of their development as an adult. We included additional indicators of service use to better understand the relationship between childhood behaviour and subsequent use of health and medical services.We expected childhood aggression to increase the use of health services. Previous data from the Concordia Longitudinal Risk Project^9,10 and other studies^11–13 show that childhood aggression in girls was predictive of poorer gynecologic health (particularly in late adolescence and early adulthood) and an increased number of early pregnancies. Although the focus of our study was on physical health and use of services associated with childhood aggression, the inclusion of childhood social withdrawal and childhood likeability are strengths of the Concordia Project. The longitudinal sequelae of these childhood behavioural and social characteristics are less well-documented and have rarely been studied longitudinally in the context of physical health. We expected childhood social withdrawal and likeability to lead to less overall use of health care and to be protective, specifically against injuries and obstetric and gynecologic conditions.     

Leaf optical properties reflect variation in photosynthetic metabolism and its sensitivity to temperature

Researchers from a number of disciplines have long sought the ability to estimate the functional attributes of plant canopies, such as photosynthetic capacity, using remotely sensed data. To date, however, this goal has not been fully realized. In this study, fresh-leaf reflectance spectroscopy (λ=450-2500 nm) and a partial least-squares regression (PLSR) analysis were used to estimate key determinants of photosynthetic capacity-namely the maximum rates of RuBP carboxylation (V(cmax)) and regeneration (J(max))-measured with standard gas exchange techniques on leaves of trembling aspen and eastern cottonwood trees. The trees were grown across an array of glasshouse temperature regimes. The PLSR models yielded accurate and precise estimates of V(cmax) and J(max) within and across species and glasshouse temperatures. These predictions were developed using unique contributions from different spectral regions. Most of the wavelengths selected were correlated with known absorption features related to leaf water content, nitrogen concentration, internal structure, and/or photosynthetic enzymes. In a field application of our PLSR models, spectral reflectance data effectively captured the short-term temperature sensitivities of V(cmax) and J(max) in aspen foliage. These findings highlight a promising strategy for developing remote sensing methods to characterize dynamic, environmentally sensitive aspects of canopy photosynthetic metabolism at broad scales.     

Importance of Different Volatile Petroleum Hydrocarbon Fractions in Human Health Risk Assessment

Soil vapor data for benzene and four aliphatic and aromatic hydrocarbon fractions from five volatile petroleum hydrocarbon (VPH)-contaminated sites in western Canada were used together with the Canadian Council of Ministers of the Environment (CCME) Canada-Wide Standard for petroleum hydrocarbons to investigate the relative importance of benzene and the different fractions in human health risk assessment. VPH concentrations in soil vapor samples ranged from 4.0 to 4200?mg/m³, of which 0 to 4.6% was BTEX and 90 to 95% was hydrocarbons of the C_5–8 aliphatic fraction. VPH inhalation exposure by an adult receptor in a hypothetical, commercial building was modelled deterministically assuming 16- and 70 year occupational tenures. The magnitude of hazard quotients varied widely between sites, but their hydrocarbon fraction signatures were consistent, and characterized by higher hazard quotients in the C_5–8 and C_9–10 aliphatic and C_9–10 aromatic fractions relative to benzene and the TEX aromatic fraction. This work has shown that the C_5– and C_9–10 aliphatic fractions yield greater relative risk than the commonlyregulated TEX compounds, and that benzene becomes the primary chemical of potential concern only when an occupational tenure approaching 70 years is assumed.