Functional Breadth Research Articles

Molecular analysis and bioinformatic characterization of cooper, zinc-superoxide dismutase (Cu/Zn-sod) gene of Caiman latirostris.

Superoxide dismutase (SOD) is an antioxidant enzyme that acts as a component of first-line defense system against reactive oxygen species (ROS). Copper/Zinc superoxide dismutase (Cu/Zn-SOD) is one of the isoforms of SOD enzyme and is sensitive to the exposure of different environmental factors, in different species and tissues. Caiman latirostris is one of the two crocodilian species living in Argentina and no information is available on the molecular and biochemical characteristics of the Cu/Zn-sod gene in this species. In the present work, we reported the presence of the Cu/Zn-sod gene in C. latirostris, the nucleotide and amino acid sequences, the modelled protein structure, evolutionary distance among species and tissue specific expression patterns. Cu/Zn-sod gene was 620bp open reading frame in length and encoded 178 amino acids. The nucleotide sequences of C. latirostris shared high similarity with the Cu/Zn-sod genes of other crocodilian species, so it showed to be highly conserved. PCR analysis showed that Cu/Zn-sod gene was expressed in all the tissues examined (liver, gonads, spleen, heart, and whole blood), suggesting a constitutively expressed gene in these tissues. This study allows further investigation into the structure-activity relationship and the mechanism of action of Cu/Zn-SOD, besides exploring the functional breadth and possible alteration factors, including xenobiotics.

Understanding managerial ambidexterity: a people–situation interaction approach

PurposeIt is increasingly recognised that managers play a central role in organisational ambidexterity. While some scholars have recently begun to explain the nature and antecedents of ambidextrous behaviour among managers, much remains to be learned about the micro-foundations of this behaviour. Adopting a people–situation interaction approach, this paper investigates the antecedents to managerial ambidexterity from both situational and individual difference considerations.Design/methodology/approachThis study adopts a quantitative approach using a combination of survey and archival data from 305 managers.FindingsThe results indicate that learning goal orientation is positively related with managerial ambidexterity, whereas there is no significant relationship between functional experience breadth and managerial ambidexterity. In testing moderation effects, discretionary slack is found to positively moderate the association between learning goal orientation and ambidexterity and between functional experiences and ambidexterity.Practical implicationsThis paper provides suggestions on employees selection and training, along with organisational support, in enacting managerial ambidexterity.Originality/valueGuided by individual difference theory, this paper adds value to one’s understanding of the antecedents to managerial ambidexterity. It contributes to the ambidexterity literature from the micro-foundation perspective.

Modulation of solute diffusivity in brain tissue as a novel mechanism of transcranial direct current stimulation (tDCS)

The breadth of brain disorders and functions reported responsive to transcranial direct current stimulation (tDCS) suggests a generalizable mechanism of action. Prior efforts characterized its cellular targets including neuron, glia and endothelial cells. We propose tDCS also modulates the substance transport in brain tissue. High resolution multiphoton microscopy imaged the spread across rat brain tissue of fluorescently-labeled solutes injected through the carotid artery after tDCS. The effective solute diffusion coefficient of brain tissue (Deff) was determined from the spatio-temporal solute concentration profiles using an unsteady diffusion transport model. 5–10 min post 20 min–1 mA tDCS, Deff increased by ~ 10% for a small solute, sodium fluorescein, and ~ 120% for larger solutes, BSA and Dex-70k. All increases in Deff returned to the control level 25–30 min post tDCS. A mathematical model for Deff in the extracelluar space (ECS) further predicts that this dose of tDCS increases Deff by transiently enhancing the brain ECS gap spacing by ~ 1.5-fold and accordingly reducing the extracellular matrix density. The cascades leading ECS modulation and its impact on excitability, synaptic function, plasticity, and brain clearance require further study. Modulation of solute diffusivity and ECS could explain diverse outcomes of tDCS and suggest novel therapeutic strategies.

Approaches to Investigating the Protein Interactome of PTEN

The tumor suppressor phosphatase and tensin homologue (PTEN) is a redox-sensitive dual specificity phosphatase with an essential role in the negative regulation of the PI3K-AKT signaling pathway, affecting metabolic and cell survival processes. PTEN is commonly mutated in cancer, and dysregulation in the metabolism of PIP3 is implicated in other diseases such as diabetes. PTEN interactors are responsible for some functional roles of PTEN beyond the negative regulation of the PI3K pathway and are thus of great importance in cell biology. Both high-data content proteomics-based approaches and low-data content PPI approaches have been used to investigate the interactome of PTEN and elucidate further functions of PTEN. While low-data content approaches rely on co-immunoprecipitation and Western blotting, and as such require previously generated hypotheses, high-data content approaches such as affinity pull-down proteomic assays or the yeast 2-hybrid system are hypothesis generating. This review provides an overview of the PTEN interactome, including redox effects, and critically appraises the methods and results of high-data content investigations into the global interactome of PTEN. The biological significance of findings from recent studies is discussed and illustrates the breadth of cellular functions of PTEN that can be discovered by these approaches.

Gene Dispensability in Escherichia coli Grown in Thirty Different Carbon Environments.

Central metabolism is a topic that has been studied for decades, and yet, this process is still not fully understood in Escherichia coli, perhaps the most amenable and well-studied model organism in biology. To further our understanding, we used a high-throughput method to measure the growth kinetics of each of 3,796 E. coli single-gene deletion mutants in 30 different carbon sources. In total, there were 342 genes (9.01%) encompassing a breadth of biological functions that showed a growth phenotype on at least 1 carbon source, demonstrating that carbon metabolism is closely linked to a large number of processes in the cell. We identified 74 genes that showed low growth in 90% of conditions, defining a set of genes which are essential in nutrient-limited media, regardless of the carbon source. The data are compiled into a Web application, Carbon Phenotype Explorer (CarPE), to facilitate easy visualization of growth curves for each mutant strain in each carbon source. Our experimental data matched closely with the predictions from the EcoCyc metabolic model which uses flux balance analysis to predict growth phenotypes. From our comparisons to the model, we found that, unexpectedly, phosphoenolpyruvate carboxylase (ppc) was required for robust growth in most carbon sources other than most trichloroacetic acid (TCA) cycle intermediates. We also identified 51 poorly annotated genes that showed a low growth phenotype in at least 1 carbon source, which allowed us to form hypotheses about the functions of these genes. From this list, we further characterized the ydhC gene and demonstrated its role in adenosine efflux.IMPORTANCE While there has been much study of bacterial gene dispensability, there is a lack of comprehensive genome-scale examinations of the impact of gene deletion on growth in different carbon sources. In this context, a lot can be learned from such experiments in the model microbe Escherichia coli where much is already understood and there are existing tools for the investigation of carbon metabolism and physiology (1). Gene deletion studies have practical potential in the field of antibiotic drug discovery where there is emerging interest in bacterial central metabolism as a target for new antibiotics (2). Furthermore, some carbon utilization pathways have been shown to be critical for initiating and maintaining infection for certain pathogens and sites of infection (3-5). Here, with the use of high-throughput solid medium phenotyping methods, we have generated kinetic growth measurements for 3,796 genes under 30 different carbon source conditions. This data set provides a foundation for research that will improve our understanding of genes with unknown function, aid in predicting potential antibiotic targets, validate and advance metabolic models, and help to develop our understanding of E. coli metabolism.

Ecosystem Functioning of Great Salt Lake Wetlands

Like many wetlands worldwide, Great Salt Lake (GSL) wetlands have been declining. Yet, little is known about the ecosystem functions provided by the different GSL wetland plant species. This knowledge gap hinders predictions of the effects of species loss and restoration practices on ecosystem functioning. To better understand how the loss of different habitat types affects the provisioning of ecosystem functions, we quantified eight functions and multifunctionality (the support of multiple functions simultaneously) across seven dominant GSL wetland habitat types. Habitats varied greatly in their capacity to perform functions. However, no single habitat type supported all eight functions even at 20% of the maximum value for each individual function. We found that native plants Typha latifolia and Schoenoplectus acutus and invasive Phragmites australis had the highest levels of multifunctionality. Although these three species were able to support more functions, we found that a diversity of habitats are required to maintain the breadth of ecosystem functions examined. This study supports the idea that habitat heterogeneity is critical in supporting a multifunctional environment, and that habitat homogenization may cause a reduction in functioning provided by GSL wetlands.

Soil Microbial Community and Litter Quality Controls on Decomposition Across a Tropical Forest Disturbance Gradient

Industrial logging and agricultural expansion are driving rapid transformations of tropical ecosystems, modifying patterns in above-ground plant and below-ground microbial communities. However, the extent to which these changes in biodiversity drive modifications of ecosystem process rates such as leaf litter decomposition is poorly understood. To determine the relative effects of changes to the chemical quality of litter and shifts in microbial decomposers on leaf litter decomposition rates, we performed a controlled, reciprocal transplant, litter decomposition experiment across a tropical land-use disturbance gradient. Litter mixtures and soils were collected from old growth forest, moderately logged forest, heavily logged forest, and oil palm plantation in Sabah, Malaysia, and combined in a fully crossed, factorial microcosm experiment maintained under controlled environmental conditions. We found that whilst litter quality was the most important predictor of litter mass loss, soil origin was also significant, explaining between 5.17 and 15.43% of total variation. Microbial decomposer communities from old growth forest had greater functional breadth relative to those from logged forests and oil palm plantation as all litter types decomposed faster when combined with old growth soil. The most chemically recalcitrant litter (lowest N, highest lignin, lignin:N, and C:N ratio) from moderate logged forest decomposed faster when combined with its “home” soil (Home-Field Advantage) whilst the most labile litter from oil palm decomposed slowest when combined with its “home” soil. This was correlated with lower total soil microbial biomass. Taken together, these findings demonstrate that whilst litter quality regulated rates of litter decomposition across the disturbance gradient, soil microbial decomposer communities were functionally dissimilar between land uses and explained a significant proportion of variation. The impact of disturbance on soil, including microbial community structure, should be considered alongside changes to plant communities when assessing effects on crucial ecosystem processes such as decomposition.

Heterosubtypic human antibody response to influenza H7N9 in survivors of natural infection

Abstract H7N9 avian influenza virus causes severe infections in humans after cross-species transmission from bird reservoirs. Previous studies revealed that infection with H7N9 elicits a heterosubtypic polyclonal antibody (Ab) response between H7 and H3 or H1 hemagglutinins (HAs) in humans. However, relatively little is known about the functional activity, targeted epitopes, and breadth of reactivity of human monoclonal Abs (mAbs) against H7N9. In this study, we isolated 18 H7-reactive mAbs from survivors of natural H7N9 infection. The majority (14 of 18) of H7-reactive mAbs within the panel possessed neutralizing activity, mediated by inhibition of attachment or egress of the virus. Binding analysis of the isolated mAbs against fourteen influenza virus HAs representing group 1 and 2 revealed cross-reactivity for diverse strains within the H7 subtype and an extended response to H15 HA. Seven identified cross-reactive mAbs targeted the HA head domain, including neutralizing and non-neutralizing mAbs. Two neutralizing mAbs that are specific to the HA stem region revealed heterosubtypic reactivity against H7, H15 and H3 HAs. Further analysis identified the epitopes for heterosubtypic mAbs. This study provides insights into the basis for heterosubtypic antibody responses against H7N9 in human infection survivors and may inform efforts to incorporate novel epitope targets in broadly protective influenza vaccines.

Identification of Particles in Exhaled Air Using Mass Spectrometry

Bronchiolitis obliterans syndrome (BOS) as a form of chronic lung allograft dysfunction is a limiting factor to the survival of lung transplant recipients. Detection and monitoring of chronic rejection is hampered by a lack of clinically available markers. Particles in exhaled air (PExA) is proposed as a noninvasive means of potentially identifying and observing BOS patients. This pilot study aims to capture the range of exhaled particles expected in human samples and identify possible candidate markers. The PExA device collects exhaled air using a two-way valve that allows subjects to inhale filtered air and exhale air into a reservoir from which an optical particle counter counts and sizes entering particles. Particles are collected according to their inertia and those above a threshold impact onto a plate, collecting onto a membrane of polytetrafluoroethylene. Total accumulated mass can be measured by the PExA device. Samples were obtained from two healthy subjects (1 combined 600 ng sample and 200 ng from each) and from five patients with lung pathology (1 grouped sample of 600 ng from three patients and 200 ng samples from two unique patients). The samples were analyzed via liquid chromatography-mass spectrometry on an Orbitrap Fusion Lumos mass spectrometer coupled to an easy-nLC1200 liquid chromatography system. The fifty most abundant proteins identified by mass spectrometry represented a breadth of biological function and a variety of localizations. Ten could be traced to immunological system processes and included a number of immunoglobulin constant regions. Sixteen of these most abundant proteins could be found in the extracellular region. A number are components of the plasma, including serotransferrin and annexin proteins. Fifteen proteins were found in greater abundance in the healthy subjects compared to patients while two (haptoglobin and gasdermin-A) were notable for a lower abundance in the patients. The PExA device presents as a novel method for non-invasive analysis of lung transplant patients with the potential to monitor developing chronic rejection. This pilot study characterizes the range of proteins identified from samples across subjects and serves as a basis for the exploration of markers in chronic rejection patients. This work establishes a method for the ongoing effort to use PExA to identify and monitor BOS in lung transplant recipients.

The Cajal Body in Plant-Virus Interactions.

Cajal bodies (CBs) are nuclear membraneless bodies composed of proteins and RNA. Although it is known that CBs play a role in RNA metabolism and the formation of functional ribonucleoprotein (RNP) particles, the whole breadth of CB functions is far from being fully elucidated. In this short review, we will summarize and discuss the growing body of evidence pointing to an involvement of this subnuclear compartment in plant-virus interactions.

DEAD-Box Helicases: Sensors, Regulators, and Effectors for Antiviral Defense.

DEAD-box helicases are a large family of conserved RNA-binding proteins that belong to the broader group of cellular DExD/H helicases. Members of the DEAD-box helicase family have roles throughout cellular RNA metabolism from biogenesis to decay. Moreover, there is emerging evidence that cellular RNA helicases, including DEAD-box helicases, play roles in the recognition of foreign nucleic acids and the modulation of viral infection. As intracellular parasites, viruses must evade detection by innate immune sensing mechanisms and degradation by cellular machinery while also manipulating host cell processes to facilitate replication. The ability of DEAD-box helicases to recognize RNA in a sequence-independent manner, as well as the breadth of cellular functions carried out by members of this family, lead them to influence innate recognition and viral infections in multiple ways. Indeed, DEAD-box helicases have been shown to contribute to intracellular immune sensing, act as antiviral effectors, and even to be coopted by viruses to promote their replication. However, our understanding of the mechanisms underlying these interactions, as well as the cellular roles of DEAD-box helicases themselves, is limited in many cases. We will discuss the diverse roles that members of the DEAD-box helicase family play during viral infections.

Endothelial cells and organ function: applications and implications of understanding unique and reciprocal remodelling.

The microvasculature is a heterogeneous, dynamic and versatile component of the systemic circulation, with a unique ability to locally self‐regulate and to respond to organ demand and environmental stimuli. Endothelial cells from different organs display considerable variation, but it is currently unclear to what extent functional properties of organ‐specific endothelial cells are intrinsic, acquired and/or reprogrammable. Vascular function is a fundamental pillar of homeostasis, and dysfunction results in systemic consequences for the organism. Additionally, vascular failure can occur downstream of organ disease or environmental stress, often driving an exacerbation of symptoms and pathologies originally independent of the local circulation. The understanding of the molecular mechanisms underlying endothelial physiology and metabolism holds the promise to inform and improve diagnosis, prognosis and treatment options for a myriad of conditions as unrelated as cancer, neurodegeneration or pulmonary hypertension, and likely everything in between, if we consider that also treatments for such conditions are primarily distributed via the bloodstream. However, studying endothelial function has its challenges: the origin, isolation, culture conditions and preconditioning stimuli make this an extremely variable cell type to study and difficult to source. Animal models exist but are neither trivial to generate, nor necessarily adequately translatable to human disease. In this article, we aim to illustrate the breadth of microvascular functions in different environments, highlighting current and pioneering studies that have advanced our insight into the importance of the integrity of this tissue, as well as the limitations posed by its heterogeneity and plasticity.

Analysis of the commercialization from the Enem by the three schools better ranked in 2015 from the city of São Paulo.

This work discusses the use of the ENEM ranking by a group of private schools in the city of São Paulo for commercial purposes and explcity through the data obtained from Instituto Nacional de Estudos e Pesquisas Educacionais Anísio Teixeira (INEP), how the families are led to look for these schools because of the disclosure of results with criteria and deficit of information, starting an "intellectual auction" for the search for scholarships to attend high school. It is well-known that the students' dispute between private schools in São Paulo has been fierce over the years and the transitions made by them tend to happen at the end of the last grade of Elementary School II (9th Year), so, after having done all training in an institution, in the final portion of their preparation, students tend to look for specialized entrance schools and better ranked in the ENEM. We observed that these elements end up distorting the real breadth of the school function that starts to adopt measures to keep its students and just prepare for the entrance exam.

Niche breadth and species richness: Correlation strength, scale and mechanisms

AbstractAimIt is often assumed that species in richer sites are more specialized, but empirical studies show conflicting results. In the present study, we quantify the correlation between community‐level niche breadth and richness. We contrast three mechanisms for gradients in niche breadth: climate, community assembly and nested interactions. First, the climatic stability within the tropics enables species to specialize, resulting in high richness. Under this scenario, we predict stronger richness–niche breadth correlations over larger latitudinal extents and when using environmental niche breadth measures (e.g., habitat). Second, in species‐rich areas, biotic interactions drive species to specialize. This may yield richness–niche breadth correlations regardless of the latitudinal extent and the type of niche breadth measure examined, whether environmental or functional (e.g., diet). Third, increased richness intensifies interactions between extreme specialists and generalists. Here, we predict stronger richness–niche breadth correlations when using functional niche breadth measures.LocationGlobal.Time period1973–2018.Major taxa studiedMany taxa.MethodsWe conducted a meta‐analysis, with the effect size estimated as the correlation between richness and community‐averaged niche breadth extracted from each study. We also examined how these correlations depend on the niche breadth measure used (environmental or functional), scale (grain and latitudinal extent), ecosystem and taxa.ResultsWe found a strong negative correlation between richness and niche breadth, and overall, a non‐significant correlation between latitude and niche breadth. The richness–niche breadth correlation was independent of the niche breadth measure used (environmental or functional). Scale, ecosystem and taxa had little effect on the strength of the correlation.Main conclusionsWe confirm that species in richer sites, but not necessarily in the tropics, are more specialized. This finding is not dependent on scale or on the type of niche breadth measure used. These results suggest that high richness drives community‐level specialization, and thus community assembly is likely to be the major driver of niche breadth rather than climatic gradients shaping both niche breadth and richness.

Interdomain communication suppressing high intrinsic ATPase activity of Sse1 is essential for its co-disaggregase activity with Ssa1.

In eukaryotes, Hsp110s are unambiguous cognates of the Hsp70 chaperones, in primary sequence, domain organization, and structure. Hsp110s function as nucleotide exchange factors (NEFs) for the Hsp70s although their apparent loss of Hsp70-like chaperone activity, nature of interdomain communication, and breadth of domain functions are still puzzling. Here, by combining single-molecule FRET, small angle X-ray scattering measurements (SAXS), and MD simulation, we show that yeast Hsp110, Sse1 lacks canonical Hsp70-like interdomain allostery. However, the protein exhibits unique noncanonical conformational changes within its domains. Sse1 maintains an open-lid substrate-binding domain (SBD) in close contact with its nucleotide-binding domain (NBD), irrespective of its ATP hydrolysis status. To further appreciate such ATP-hydrolysis-independent exhaustive interaction between two domains of Hsp110s, NBD-SBD chimera was constructed between Hsp110 (Sse1) and Hsp70 (Ssa1). In Sse1/Ssa1 chimera, we observed undocking of two domains leading to complete loss of NEF activity of Sse1. Interestingly, chimeric proteins exhibited significantly enhanced ATPase rate of Sse1-NBD compared to wild-type protein, implying that intrinsic ATPase activity of the protein remains mostly repressed. Apart from repressing the high ATPase activity of its NBD, interactions between two domains confer thermal stability to Sse1 and play critical role in the (co)chaperoning function of Sse1 in Ssa1-mediated disaggregation activity. Altogether, Sse1 exhibits a unique interdomain interaction, which is essential for its NEF activity, suppression of high intrinsic ATPase activity, co-chaperoning activity in disaggregase machinery, and stability of the protein.

Molecular Origins of Functional Diversity in Benzylisoquinoline Alkaloid Methyltransferases.

O- and N-methylations are ubiquitous and recurring features in the biosynthesis of many specialized metabolites. Accordingly, the methyltransferase (MT) enzymes catalyzing these modifications are directly responsible for a substantial fraction of the vast chemodiversity observed in plants. Enabled by DNA sequencing and synthesizing technologies, recent studies have revealed and experimentally validated the trajectories of molecular evolution through which MTs, such as those biosynthesizing caffeine, emerge and shape plant chemistry. Despite these advances, the evolutionary origins of many other alkaloid MTs are still unclear. Focusing on benzylisoquinoline alkaloid (BIA)-producing plants such as opium poppy, we review the functional breadth of BIA N- and O-MT enzymes and their relationship with the chemical diversity of their host species. Drawing on recent structural studies, we discuss newfound insight regarding the molecular determinants of BIA MT function and highlight key hypotheses to be tested. We explore what is known and suspected concerning the evolutionary histories of BIA MTs and show that substantial advances in this domain are within reach. This new knowledge is expected to greatly enhance our conceptual understanding of the evolutionary origins of specialized metabolism.

Therapeutic Potential of Targeting ß-Arrestin.

ß-arrestins are multifunctional proteins that modulate heptahelical 7 transmembrane receptors, also known as G protein-coupled receptors (GPCRs), a superfamily of receptors that regulate most physiological processes. ß-arrestin modulation of GPCR function includes termination of G protein-dependent signaling, initiation of ß-arrestin-dependent signaling, receptor trafficking to degradative or recycling pathways, receptor transactivation, transcriptional regulation, and localization of second messenger regulators. The pleiotropic influence ß-arrestins exert on these receptors regulates a breadth of physiological functions, and additionally, ß-arrestins are involved in the pathophysiology of numerous and wide-ranging diseases, making them prime therapeutic targets. In this review, we briefly describe the mechanisms by which ß-arrestins regulate GPCR signaling, including the functional cellular mechanisms modulated by ß-arrestins and relate this to observed pathophysiological responses associated with ß-arrestins. We focus on the role for ß-arrestins in transducing cell signaling; a pathway that is complementary to the classical G protein-coupling pathway. The existence of these GPCR dual signaling pathways offers an immense therapeutic opportunity through selective targeting of one signaling pathway over the other. Finally, we will consider several mechanisms by which the potential of dual signaling pathway regulation can be harnessed and the implications for improved disease treatments.

Delayed diagnosis of multiple sclerosis in males: may account for and dispel common understandings of different MS 'types'.

Multiple sclerosis (MS) is a long-term neurodegenerative condition that affects functioning of the central nervous system, and estimates of its prevalence range from 1–2.5 million people diagnosed worldwide.1,2 Just as the central nervous system mediates a breadth of bodily functions, MS can manifest in varied ways, often leading to confusion as to whether ill-health is caused by MS or something else. MS trajectories vary between individuals, and different MS ‘types’ are commonly used to describe patterns. Relapsing remitting MS (RRMS) refers to short-term exacerbations (relapses) and recovery (remission); secondary progressive MS (SPMS) develops after RRMS and describes long-term permanent neurodegeneration. Primary progressive MS (PPMS) also refers to long-term permanent neurodegeneration, but without a relapsing remitting stage preceding it.3 Although these different MS ‘types’ are commonly referred to within professional and lay circles, individuals’ trajectories do not always fit comfortably into their descriptions,4 no biomarkers have been identified to distinguish between them,5 and they are not recognised as subtypes in the World Health Organization’s International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10).6 Internationally MS appears to be more prevalent in females than males1,7 and the difference in ratio seems to be rising,8 except in the case of PPMS, where those diagnosed are more likely to be male and older.9 Previous research indicates no clear cause for apparent sex …

Influence of input and parameter uncertainty on the prediction of catchment-scale groundwater travel time distributions

Abstract. Groundwater travel time distributions (TTDs) provide a robust description of the subsurface mixing behavior and hydrological response of a subsurface system. Lagrangian particle tracking is often used to derive the groundwater TTDs. The reliability of this approach is subjected to the uncertainty of external forcings, internal hydraulic properties, and the interplay between them. Here, we evaluate the uncertainty of catchment groundwater TTDs in an agricultural catchment using a 3-D groundwater model with an overall focus on revealing the relationship between external forcing, internal hydraulic properties, and TTD predictions. Eight recharge realizations are sampled from a high-resolution dataset of land surface fluxes and states. Calibration-constrained hydraulic conductivity fields (Ks fields) are stochastically generated using the null-space Monte Carlo (NSMC) method for each recharge realization. The random walk particle tracking (RWPT) method is used to track the pathways of particles and compute travel times. Moreover, an analytical model under the random sampling (RS) assumption is fit against the numerical solutions, serving as a reference for the mixing behavior of the model domain. The StorAge Selection (SAS) function is used to interpret the results in terms of quantifying the systematic preference for discharging young/old water. The simulation results reveal the primary effect of recharge on the predicted mean travel time (MTT). The different realizations of calibration-constrained Ks fields moderately magnify or attenuate the predicted MTTs. The analytical model does not properly replicate the numerical solution, and it underestimates the mean travel time. Simulated SAS functions indicate an overall preference for young water for all realizations. The spatial pattern of recharge controls the shape and breadth of simulated TTDs and SAS functions by changing the spatial distribution of particles' pathways. In conclusion, overlooking the spatial nonuniformity and uncertainty of input (forcing) will result in biased travel time predictions. We also highlight the worth of reliable observations in reducing predictive uncertainty and the good interpretability of SAS functions in terms of understanding catchment transport processes.

Lean-Agile FM-BIM: a demonstrated approach

PurposeThis paper aims to respond to the high cost of facility management-enabled building information model (FM-BIM) creation and maintenance, a significant and under-researched barrier to adoption for existing buildings. The resultant approach focuses on only value-adding content (“Lean”) developed flexibly and iteratively in collaboration with end-users (“Agile”).Design/methodology/approachFive case studies were developed for university and hospital buildings in collaboration with end-users, guided by the process presented. These informed the refinement of a robust and flexible approach to increase BIM functionality with minimal geometry, focusing instead on the development of specific parameters to map semantic information necessary for each desired FM use.FindingsThe resulting BIM provided a breadth of model functionality with minimal modeling effort: 15 hours average implementation time per supported FM use. This low level of effort was achieved by limiting geometry to where it is necessary for the FM use implementation. Instead, the model incorporated the majority of geometry by reference and focused on semantic and topological parameters to house FM information.Research limitations/implicationsThis study provides the basis for a new ontology structure focused on defining the rules for hosting asset management data (host entity, parameter type and characteristics) to reduce the reliance on complex geometric model development.Practical implicationsBy prioritizing highly beneficial applications, early investment is minimized, providing quick returns at low risk, demonstrating the value of FM-BIM to end-users.Originality/valueThe Lean-Agile approach addresses the known research gap of low-effort, flexible approaches to FM-BIM model creation and maintenance and its effectiveness is analyzed through five case studies.