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Ecosystem modeling, a pillar of the systems ecology paradigm (SEP), addresses questions such as, how much carbon and nitrogen are cycled within ecological sites, landscapes, or indeed the earth system? Or how are human activities modifying these flows? Modeling, when coupled with field and laboratory studies, represents the essence of the SEP in that they embody accumulated knowledge and generate hypotheses to test understanding of ecosystem processes and behavior. Initially, ecosystem models were primarily used to improve our understanding about how biophysical aspects of ecosystems operate. However, current ecosystem models are widely used to make accurate predictions about how large-scale phenomena such as climate change and management practices impact ecosystem dynamics and assess potential effects of these changes on economic activity and policy making. In sum, ecosystem models embedded in the SEP remain our best mechanism to integrate diverse types of knowledge regarding how the earth system functions and to make quantitative predictions that can be confronted with observations of reality. Modeling efforts discussed are the Century ecosystem model, DayCent ecosystem model, Grassland Ecosystem Model ELM, food web models, Savanna model, agent-based and coupled systems modeling, and Bayesian modeling.
The systems ecology paradigm (SEP) emerged in the late 1960s at a time when societies throughout the world were beginning to recognize that our environment and natural resources were being threatened by their activities. Management practices in rangelands, forests, agricultural lands, wetlands, and waterways were inadequate to meet the challenges of deteriorating environments, many of which were caused by the practices themselves. Scientists recognized an immediate need was developing a knowledge base about how ecosystems function. That effort took nearly two decades (1980s) and concluded with the acceptance that humans were components of ecosystems, not just controllers and manipulators of lands and waters. While ecosystem science was being developed, management options based on ecosystem science were shifting dramatically toward practices supporting sustainability, resilience, ecosystem services, biodiversity, and local to global interconnections of ecosystems. Emerging from the new knowledge about how ecosystems function and the application of the systems ecology approach was the collaboration of scientists, managers, decision-makers, and stakeholders locally and globally. Today’s concepts of ecosystem management and related ideas, such as sustainable agriculture, ecosystem health and restoration, consequences of and adaptation to climate change, and many other important local to global challenges are a direct result of the SEP.
Fundamental knowledge about the processes that control the functioning of the biophysical workings of ecosystems has expanded exponentially since the late 1960s. Scientists, then, had only primitive knowledge about C, N, P, S, and H2O cycles; plant, animal, and soil microbial interactions and dynamics; and land, atmosphere, and water interactions. With the advent of systems ecology paradigm (SEP) and the explosion of technologies supporting field and laboratory research, scientists throughout the world were able to assemble the knowledge base known today as ecosystem science. This chapter describes, through the eyes of scientists associated with the Natural Resource Ecology Laboratory (NREL) at Colorado State University (CSU), the evolution of the SEP in discovering how biophysical systems at small scales (ecological sites, landscapes) function as systems. The NREL and CSU are epicenters of the development of ecosystem science. Later, that knowledge, including humans as components of ecosystems, has been applied to small regions, regions, and the globe. Many research results that have formed the foundation for ecosystem science and management of natural resources, terrestrial environments, and its waters are described in this chapter. Throughout are direct and implicit references to the vital collaborations with the global network of ecosystem scientists.
Emerging from the warehouse of knowledge about terrestrial ecosystem functioning and the application of the systems ecology paradigm, exemplified by the power of simulation modeling, tremendous strides have been made linking the interactions of the land, atmosphere, and water locally to globally. Through integration of ecosystem, atmospheric, soil, and more recently social science interactions, plausible scenarios and even reasonable predictions are now possible about the outcomes of human activities. The applications of that knowledge to the effects of changing climates, human-caused nitrogen enrichment of ecosystems, and altered UV-B radiation represent challenges addressed in this chapter. The primary linkages addressed are through the C, N, S, and H2O cycles, and UV-B radiation. Carbon dioxide exchanges between land and the atmosphere, N additions and losses to and from lands and waters, early studies of SO2 in grassland ecosystem, and the effects of UV-B radiation on ecosystems have been mainstays of research described in this chapter. This research knowledge has been used in international and national climate assessments, for example the IPCC, US National Climate Assessment, and Paris Climate Accord. Likewise, the knowledge has been used to develop concepts and technologies related to sustainable agriculture, C sequestration, and food security.
The Minnesota Center for Twin and Family Research (MCTFR) comprises multiple longitudinal, community-representative investigations of twin and adoptive families that focus on psychological adjustment, personality, cognitive ability and brain function, with a special emphasis on substance use and related psychopathology. The MCTFR includes the Minnesota Twin Registry (MTR), a cohort of twins who have completed assessments in middle and older adulthood; the Minnesota Twin Family Study (MTFS) of twins assessed from childhood and adolescence into middle adulthood; the Enrichment Study (ES) of twins oversampled for high risk for substance-use disorders assessed from childhood into young adulthood; the Adolescent Brain (AdBrain) study, a neuroimaging study of adolescent twins; and the Siblings Interaction and Behavior Study (SIBS), a study of adoptive and nonadoptive families assessed from adolescence into young adulthood. Here we provide a brief overview of key features of these established studies and describe new MCTFR investigations that follow up and expand upon existing studies or recruit and assess new samples, including the MTR Study of Relationships, Personality, and Health (MTR-RPH); the Colorado-Minnesota (COMN) Marijuana Study; the Adolescent Brain Cognitive Development (ABCD) study; the Colorado Online Twins (CoTwins) study and the Children of Twins (CoT) study.
A new deep level transient spectroscopy (DLTS) technique is described, called half-width at variable intensity analysis. This method utilizes the width and normalized intensity of a DLTS signal to determine the activation energy and capture cross section of the trap that generated the signal via a variable, kO. This constant relates the carrier emission rates giving rise to the differential capacitance signal associated with a given trap at two different temperatures: the temperature at which the maximum differential capacitance is detected, and an arbitrary temperature at which some nonzero differential capacitance signal is detected. The extracted activation energy of the detected trap center is used along with the position of the peak maximum to extract the capture cross section of the trap center.
Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88) presented a critique of our recently published paper in Cell Reports entitled ‘Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets’ (Lam et al., Cell Reports, Vol. 21, 2017, 2597–2613). Specifically, Hill offered several interrelated comments suggesting potential problems with our use of a new analytic method called Multi-Trait Analysis of GWAS (MTAG) (Turley et al., Nature Genetics, Vol. 50, 2018, 229–237). In this brief article, we respond to each of these concerns. Using empirical data, we conclude that our MTAG results do not suffer from ‘inflation in the FDR [false discovery rate]’, as suggested by Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88), and are not ‘more relevant to the genetic contributions to education than they are to the genetic contributions to intelligence’.
An internationally approved and globally used classification scheme for the diagnosis of CHD has long been sought. The International Paediatric and Congenital Cardiac Code (IPCCC), which was produced and has been maintained by the International Society for Nomenclature of Paediatric and Congenital Heart Disease (the International Nomenclature Society), is used widely, but has spawned many “short list” versions that differ in content depending on the user. Thus, efforts to have a uniform identification of patients with CHD using a single up-to-date and coordinated nomenclature system continue to be thwarted, even if a common nomenclature has been used as a basis for composing various “short lists”. In an attempt to solve this problem, the International Nomenclature Society has linked its efforts with those of the World Health Organization to obtain a globally accepted nomenclature tree for CHD within the 11th iteration of the International Classification of Diseases (ICD-11). The International Nomenclature Society has submitted a hierarchical nomenclature tree for CHD to the World Health Organization that is expected to serve increasingly as the “short list” for all communities interested in coding for congenital cardiology. This article reviews the history of the International Classification of Diseases and of the IPCCC, and outlines the process used in developing the ICD-11 congenital cardiac disease diagnostic list and the definitions for each term on the list. An overview of the content of the congenital heart anomaly section of the Foundation Component of ICD-11, published herein in its entirety, is also included. Future plans for the International Nomenclature Society include linking again with the World Health Organization to tackle procedural nomenclature as it relates to cardiac malformations. By doing so, the Society will continue its role in standardising nomenclature for CHD across the globe, thereby promoting research and better outcomes for fetuses, children, and adults with congenital heart anomalies.
The Yellow Chat Epthianura crocea is comprised of three disjunct subspecies. Subspecies E. c. macgregori (Capricorn Yellow Chat) is listed as Critically Endangered under the EPBC Act and has a distribution that also appears to be disjunct, with a limited geographic area of less than 7,000 ha. Some populations are threatened by rapid industrial development, and it is important for conservation of the subspecies to determine the extent to which the putative populations are connected. We used 14 microsatellite markers to measure genetic diversity and to determine the extent of gene flow between two disjunct populations at the northern and southern extremes of the subspecies’ range. No significant differences in genetic diversity (number of alleles and heterozygosity) were observed, but clear population structuring was apparent, with obvious differentiation between the northern and southern populations. The most likely explanation for reduced gene flow between the two populations is either the development of a geographic barrier as a consequence of shrinkage of the marine plains associated with the rise in sea levels following the last glacial maxima, or reduced connectivity across the largely unsuitable pasture and forest habitat that now separates the two populations, exacerbated by declining population size and fewer potential emigrants. Regardless of the mechanism, restricted gene flow between these two populations has important consequences for their ongoing conservation. The relative isolation of the smaller southern groups (the Fitzroy River delta and Curtis Island) from the much larger northern group (both sides of the Broad Sound) makes the southern population more vulnerable to local extinction. Conservation efforts should focus on nature refuge agreements with land owners agreeing to maintain favourable grazing management practices in perpetuity, particularly in the northern area where most chats occur. Supplemental exchanges of individuals from northern and southern populations should be explored as a way of increasing genetic diversity and reducing inbreeding.
Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990–1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
To determine whether antimicrobial-impregnated textiles decrease the acquisition of pathogens by healthcare provider (HCP) clothing.
We completed a 3-arm randomized controlled trial to test the efficacy of 2 types of antimicrobial-impregnated clothing compared to standard HCP clothing. Cultures were obtained from each nurse participant, the healthcare environment, and patients during each shift. The primary outcome was the change in total contamination on nurse scrubs, measured as the sum of colony-forming units (CFU) of bacteria.
PARTICIPANTS AND SETTING
Nurses working in medical and surgical ICUs in a 936-bed tertiary-care hospital.
Nurse subjects wore standard cotton-polyester surgical scrubs (control), scrubs that contained a complex element compound with a silver-alloy embedded in its fibers (Scrub 1), or scrubs impregnated with an organosilane-based quaternary ammonium and a hydrophobic fluoroacrylate copolymer emulsion (Scrub 2). Nurse participants were blinded to scrub type and randomly participated in all 3 arms during 3 consecutive 12-hour shifts in the intensive care unit.
In total, 40 nurses were enrolled and completed 3 shifts. Analyses of 2,919 cultures from the environment and 2,185 from HCP clothing showed that scrub type was not associated with a change in HCP clothing contamination (P=.70). Mean difference estimates were 0.118 for the Scrub 1 arm (95% confidence interval [CI], −0.206 to 0.441; P=.48) and 0.009 for the Scrub 2 rm (95% CI, −0.323 to 0.342; P=.96) compared to the control. HCP became newly contaminated with important pathogens during 19 of the 120 shifts (16%).
Antimicrobial-impregnated scrubs were not effective at reducing HCP contamination. However, the environment is an important source of HCP clothing contamination.
The study aim was to establish and quantify suicide risk following acute admissions for all major physical illnesses, for confirmatory purposes, from two independent information sources from different countries.
Record linkage of inpatient and death certificate data for 11 004 389 acute admissions for physical illnesses in England and 713 496 in Wales. The main outcome measure was standardised mortality ratios (SMRs) for suicide at 1 year following discharge from hospital.
There were 1781 suicides within 1 year of discharge in England (SMR = 1.7; 95% = 1.6–1.8) and 131 in Wales (SMR = 2.0; 1.7–2.3). Of 48 major physical illnesses that were associated with at least eight suicides in either country, there was high consistent suicide mortality (significant SMR >3) in both countries for constipation (SMR = 4.1 in England, 7.5 in Wales), gastritis (4.4 and 4.9) and upper gastrointestinal bleeding (3.4 and 4.5). There was high suicide mortality in one country for alcoholic liver disease, other liver disease and chronic pancreatitis; for epilepsy and Parkinson's disease; for diabetes, hypoglycaemia and hypo-osmolality & hyponatraemia; and for pneumonia, back pain and urinary tract infections.
There is little or no increased suicide mortality following acute admissions for most physical illnesses. Much of the increased suicide mortality relates to gastrointestinal disorders that are often alcohol related or specific chronic conditions, which may be linked to side effects from certain therapeutic medications. Acute hospital admissions for physical illnesses may therefore provide an opportunity for targeted suicide prevention among people with certain conditions, particularly alcohol related disorders.
Because individuals develop dementia as a manifestation of neurodegenerative or neurovascular disorder, there is a need to develop reliable approaches to their identification. We are undertaking an observational study (Ontario Neurodegenerative Disease Research Initiative [ONDRI]) that includes genomics, neuroimaging, and assessments of cognition as well as language, speech, gait, retinal imaging, and eye tracking. Disorders studied include Alzheimer’s disease, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson’s disease, and vascular cognitive impairment. Data from ONDRI will be collected into the Brain-CODE database to facilitate correlative analysis. ONDRI will provide a repertoire of endophenotyped individuals that will be a unique, publicly available resource.
Previous research has established that parental marital discord is associated with higher levels of offspring externalizing behaviors, but it is unclear how parental relationship functioning is associated with the genetic and environmental variance on a factor of externalizing problems. Thus, the current study assessed how parental marital discord moderates genetic and environmental variance on offspring externalizing problems at two different ages: childhood and late adolescence. That is, the magnitude of genetic and environmental influences on offspring externalizing at ages 11 and 17 was examined as a function of parental marital discord. Consistent with a diathesis–stress model of psychopathology, it was hypothesized that with increasing marital discord, genetic influences on externalizing would be more pronounced. Rather, results indicated that for the 11-year-old sample, nonshared environmental influences were greater when parental marital discord was low, and comparatively, shared environmental influences contributed more to the variance in externalizing problems when parental marital discord was high. No moderation was found for the 17-year-old cohort. In contrast to studies that do not find an effect of the shared environment, these results provide evidence that the common rearing environment has an impact on externalizing problems in preadolescent children.
Giant ragweed has been increasing as a major weed of row crops in the last
30 yr, but quantitative data regarding its pattern and mechanisms of spread
in crop fields are lacking. To address this gap, we conducted a Web-based
survey of certified crop advisors in the U.S. Corn Belt and Ontario, Canada.
Participants were asked questions regarding giant ragweed and crop
production practices for the county of their choice. Responses were mapped
and correlation analyses were conducted among the responses to determine
factors associated with giant ragweed populations. Respondents rated giant
ragweed as the most or one of the most difficult weeds to manage in 45% of
421 U.S. counties responding, and 57% of responding counties reported giant
ragweed populations with herbicide resistance to acetolactate synthase
inhibitors, glyphosate, or both herbicides. Results suggest that giant
ragweed is increasing in crop fields outward from the east-central U.S. Corn
Belt in most directions. Crop production practices associated with giant
ragweed populations included minimum tillage, continuous soybean, and
multiple-application herbicide programs; ecological factors included giant
ragweed presence in noncrop edge habitats, early and prolonged emergence,
and presence of the seed-burying common earthworm in crop fields. Managing
giant ragweed in noncrop areas could reduce giant ragweed migration from
noncrop habitats into crop fields and slow its spread. Where giant ragweed
is already established in crop fields, including a more diverse combination
of crop species, tillage practices, and herbicide sites of action will be
critical to reduce populations, disrupt emergence patterns, and select
against herbicide-resistant giant ragweed genotypes. Incorporation of a
cereal grain into the crop rotation may help suppress early giant ragweed
emergence and provide chemical or mechanical control options for
late-emerging giant ragweed.
A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.