Open Access Subvention Fund Articles

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50-kHz-rate 2D imaging of temperature and H2O concentration at the exhaust plane of a J85 engine using hyperspectral tomography
Ma, Lin; Li, Xuesong; Sanders, Scott T.; Caswell, Andrew W.; Roy, Sukesh; Plemmons, David H.; Gord, James R. (Optical Society of America, 2013-01-01)
This paper describes a novel laser diagnostic and its demonstration in a practical aero-propulsion engine (General Electric J85). The diagnostic technique, named hyperspectral tomography (HT), enables simultaneous 2-dimensional (2D) imaging of temperature and water-vapor concentration at 225 spatial grid points with a temporal response up to 50 kHz. To our knowledge, this is the first time that such sensing capabilities have been reported. This paper introduces the principles of the HT techniques, reports its operation and application in a J85 engine, and discusses its perspective for the study of high-speed reactive flows. (C) 2013 Optical Society of America
A 7-week-old male Golden Retriever with extreme leukocytosis: A case report
Bingham, Emily; Conner, Bobbi; Stern, Jere; Vitalo, Amber; Schaer, Michael (Wiley, 2020-09-27)
Although neoplasia should be a top concern for extreme leukocytosis in dogs, infectious causes must also be considered to avoid delays in treatment or undue recommendations for humane euthanasia. Blood film review is of paramount importance.
Abrogation of atypical neurogenesis and vascular-derived EphA4 prevents repeated mild TBI-induced learning and memory impairments
Greer, Kisha; Gudenschwager-Basso, Erwin K.; Kelly, Colin; Cash, Alison; Kowalski, Elizabeth A.; Cerna, Steven; Ocampo, Collin Tanchanco; Wang, Xia; Theus, Michelle H. (2020-09-21)
Brain injury resulting from repeated mild traumatic insult is associated with cognitive dysfunction and other chronic co-morbidities. The current study tested the effects of aberrant neurogenesis in a mouse model of repeated mild traumatic brain injury (rmTBI). Using Barnes Maze analysis, we found a significant reduction in spatial learning and memory at 24 days post-rmTBI compared to repeated sham (rSham) injury. Cell fate analysis showed a greater number of BrdU-labeled cells which co-expressed Prox-1 in the DG of rmTBI-injured mice which coincided with enhanced cFos expression for neuronal activity. We then selectively ablated dividing neural progenitor cells using a 7-day continuous infusion of Ara-C prior to rSham or rmTBI. This resulted in attenuation of cFos and BrdU-labeled cell changes and prevented associated learning and memory deficits. We further showed this phenotype was ameliorated in EphA4f.(/f)/Tie2-Cre knockout compared to EphA4f.(/f) wild type mice, which coincided with altered mRNA transcript levels of MCP-1, Cx43 and TGF beta. These findings demonstrate that cognitive decline is associated with an increased presence of immature neurons and gene expression changes in the DG following rmTBI. Our data also suggests that vascular EphA4-mediated neurogenic remodeling adversely affects learning and memory behavior in response to repeated insult.
Accession-Level Differentiation of Urushiol Levels, and Identification of Cardanols in Nascent Emerged Poison Ivy Seedlings
Lott, Aneirin A.; Baklajian, Emily R.; Dickinson, Christopher C.; Collakova, Eva; Jelesko, John G. (MDPI, 2019-11-20)
Poison ivy (Toxicodendron radicans (L.) Kuntze) shows accession-level differentiation in a variety of morphometric traits, suggesting local adaptation. To investigate whether the presumed defense compound urushiol also demonstrates accession-level accumulation differences, in vitro nascent germinated poison ivy seedlings from geographically isolated populations were germinated in vitro and then assayed for known urushiol congener accumulation levels. Significant accession-level differences in the accumulation levels of total C15- and C17-, total C15-, total C17-, specific C15 congeners, and specific C17 congeners of urushiol were identified. In addition, hereto novel C15- and C17-urushiol isomers were identified as well. Cardanols are assumed to be the penultimate metabolites giving rise to urushiols, but this assumption was not previously empirically validated. C15-cardanol congeners and isomers corresponding to expected substrates needed to produce the observed C15-urushiol congeners and isomers were identified in the same poison ivy seedling extracts. Total C15-cardanol and C15-cardanol congeners also showed significant accession-level differences. Based on the observed C15-cardanol congeners in poison ivy, the penultimate step in urushiol biosynthesis was proposed to be a cardanol-specific hydroxylase activity.
Acyl-Homoserine Lactone Recognition and Response Hindering the Quorum-Sensing Regulator EsaR
Schu, Daniel J.; Scruggs, Jessica M.; Geissenger, Jared S.; Michel, Katherine G.; Stevens, Ann M. (Public Library of Science, 2014-09-19)
During quorum sensing in the plant pathogen Pantoea stewartii subsp. stewartii, EsaI, an acyl-homoserine lactone (AHL) synthase, and the transcription factor EsaR coordinately control capsular polysaccharide production. The capsule is expressed only at high cell density when AHL levels are high, leading to inactivation of EsaR. In lieu of detailed structural information, the precise mechanism whereby EsaR recognizes AHL and is hindered by it, in a response opposite to that of most other LuxR homologues, remains unresolved. Hence, a random mutagenesis genetic approach was designed to isolate EsaR* variants that are immune to the effects of AHL. Error-prone PCR was used to generate the desired mutants, which were subsequently screened for their ability to repress transcription in the presence of AHL. Following sequencing, site-directed mutagenesis was used to generate all possible mutations of interest as single, rather than multiple amino acid substitutions. Eight individual amino acids playing a critical role in the AHL-insensitive phenotype have been identified. The ability of EsaR* variants to bind AHL and the effect of individual substitutions on the overall conformation of the protein were examined through in vitro assays. Six EsaR* variants had a decreased ability to bind AHL. Fluorescence anisotropy was used to examine the relative DNA binding affinity of the final two EsaR* variants, which retained some AHL binding capability but remained unresponsive to it, perhaps due to an inability of the N-terminal domain to transduce information to the C-terminal domain.
Adaptive constraints at the range edge of a widespread and expanding invasive plant
Fletcher, Rebecca A.; Atwater, Daniel Z.; Haak, David C.; Bagavathiannan, Muthukumar; DiTommaso, Antonio; Lehnhoff, Erik; Paterson, Andrew H.; Auckland, Susan; Govindasamy, Prabhu; Lemke, Cornelia; Morris, Edward; Rainville, Lisa; Barney, Jacob N. (Oxford University Press, 2023-11-05)
Identifying the factors that facilitate and limit invasive species' range expansion has both practical and theoretical importance, especially at the range edges. Here, we used reciprocal common garden experiments spanning the North/South and East/West range that include the North American core, intermediate and range edges of the globally invasive plant, Johnsongrass (Sorghum halepense) to investigate the interplay of climate, biotic interactions (i.e. competition) and patterns of adaptation. Our results suggest that the rapid range expansion of Johnsongrass into diverse environments across wide geographies occurred largely without local adaptation, but that further range expansion may be restricted by a fitness trade-off that limits population growth at the range edge. Interestingly, plant competition strongly dampened Johnsongrass growth but did not change the rank order performance of populations within a garden, though this varied among gardens (climates). Our findings highlight the importance of including the range edge when studying the range dynamics of invasive species, especially as we try to understand how invasive species will respond to accelerating global changes.
Adaptive radiation along a deeply conserved genetic line of least resistance in Anolis lizards
McGlothlin, Joel W.; Kobiela, Megan E.; Wright, Helen V.; Mahler, Luke D.; Kolbe, Jason K.; Losos, Jonathan B.; Brodie, Edmund D. III (Wiley, 2018)
On microevolutionary timescales, adaptive evolution depends upon both natural selection and the underlying genetic architecture of traits under selection, which may constrain evolutionary outcomes. Whether such genetic constraints shape phenotypic diversity over macroevolutionary timescales is more controversial, however. One key prediction is that genetic constraints should bias the early stages of species divergence along “genetic lines of least resistance” defined by the genetic (co)variance matrix, G. This bias is expected to erode over time as species means and G matrices diverge, allowing phenotypes to evolve away from the major axis of variation. We tested for evidence of this signal in West Indian Anolis lizards, an iconic example of adaptive radiation. We found that the major axis of morphological evolution was well aligned with a major axis of genetic variance shared by all species despite separation times of 20–40 million years, suggesting that divergence occurred along a conserved genetic line of least resistance. Further, this signal persisted even as G itself evolved, apparently because the largest evolutionary changes in G were themselves aligned with the line of genetic least resistance. Our results demonstrate that the signature of genetic constraint may persist over much longer timescales than previously appreciated, even in the presence of evolving genetic architecture. This pattern may have arisen either because pervasive constraints have biased the course of adaptive evolution or because the G matrix itself has been shaped by selection to conform to the adaptive landscape.
Addressing Malnutrition and Food Insecurity with Breadfruit in a Rural, Developing Country: A Case Study and Lessons Learned in Thomassique, Haiti
Klyver, John; Haugen, Inga; Schulz, Logan; LaPais, Wiscard-Kardin; Saint-Fleur, Charles; Starke, S. J.; Piersaint, Jason; Rizzo, Anael; Sarazen, Kyra (2021-09)
Haiti’s Central Plateau region suffers from significant malnutrition, economic hardship, and a crisis level of food insecurity. Already the poorest country in the Western Hemisphere in terms of GDP per capita, Haiti has pervasively high malnutrition rates, but the Central Plateau region is one of its most severely affected areas. One in five children of the Central Plateau suffers from malnutrition, and the region exhibits a 30% rate of child stunting (the highest in the country). Our US-based team affiliated with Klinik Sen Jozèf, a well-known and community-respected medical clinic in the Central Plateau city of Thomassique, partnered with local Haitian leadership and Trees That Feed Foundation to introduce the agricultural tree product called breadfruit (Artocarpus altilis) and an innovative development model to the area with the goal of combating local malnutrition. Breadfruit is highly valued in Thomassique and its surrounding villages, yet there are few local sources for it. A Haitian agronomist was hired to produce breadfruit saplings from trees donated to the clinic by Trees That Feed, and these saplings were then distributed among local farmers and community health committees. The agronomist provided appropriate crop training for breadfruit in conjunction with the sapling distribution. Four years into the program, the outcomes have been noteworthy enough to warrant sharing the process here. This article addresses the lessons learned during implementation of this program in an effort to assist others looking to introduce models or crops in a similar manner for similar purposes. While engaged in a literature review, we found very little written about how to plan and implement a program like ours, despite its potential for positively impacting the health and economic wellbeing of communities in developing nations. Our experience is particularly significant in light of the COVID-19 pandemic, as the United Nations World Food Programme projected the number of people affected by food insecurity to nearly double to 265 million worldwide by the end of 2020 as a result of it.
Adhesive Bonding Performance of Thermally Modified Yellow Poplar
Masoumi, Abasali; Balma, Francisco Xavier Zambrano; Bond, Brian H. (2023-10-16)
Thermal modification of wood changes its chemical, physical, and structural properties, which may affect adhesive bondline quality and bonding performance. This research compared the effect of thermal modification on the adhesive bonding performance of poplar (Liriodendron tulipifera) wood. Samples were prepared from thermally modified and unmodified yellow poplar using one-component polyurethane (PUR) and polyvinyl acetate (PVA), as they are adhesives used in wood products. Microscopic properties of the bondlines were investigated to understand shear performance and durability. Adhesive line thickness, penetration, shear strength, and moisture durability were measured, and failure modes were recorded. Thermal modification negatively affected the wood and adhesive interaction by reducing penetration (31.2% in PUR and 29% in PVA), therefore creating a thicker adhesive line (70% in PUR and 2% in PVA) and consequently causing a significant reduction in the shear strength of both adhesive types (27% in PUR and 36% in PVA) compared with non-modified specimens. The PUR adhesive had higher shear strength than PVA by 2.7% in non-modified and 14% in thermally modified wood.
Adjust your own oxygen mask before helping those around you: an autoethnography of participatory research
Steketee, Abby M.; Archibald, Thomas G.; Harden, Samantha M. (2020-09-03)
Background There is a need to unpack the empirical, practical, and personal challenges within participatory approaches advocated to optimize implementation. The unpredictable, chaotic nature of participatory approaches complicates application of implementation theories, methods, and strategies which do not address researchers’ situatedness within participatory processes. As an implementation scientist, addressing one’s own situatedness through critical reflection is important to unearth how conscious and unconscious approaches, including ontological and epistemological underpinnings, influence the participatory context, process, and outcomes. Therefore, the aim of this exploratory work is to investigate the heretofore blind spot toward the lived experience of implementation researchers within the participatory process. Methods We developed an integrated research-practice partnership (IRPP) to inform the implementation of a gestational weight gain (GWG) control program. Within this IRPP, one investigator conducted a 12-month autoethnography. Data collection and triangulation included field notes, cultural artifacts, and systematic timeline tracking. Data analysis included ethnographic-theoretical dialogue and restorying to synthesize key events and epiphanies into a narrative. Results Analysis revealed the unpredicted evolution of the GWG program into a maternal health fair and three themes within the researchers’ lived experience: (1) permeable work boundaries, (2) individual and collective blind spots toward the ontological and epistemological underpinnings of implementation paradigms, and (3) maladaptive behaviors seemingly reinforced by the research culture. These themes contributed to the chaos of implementation and to researchers’ experience of inadequate recovery from cognitive, emotional, and practical demands. These themes also demonstrated the importance of contextual factors, subjectivity, and value-based judgments within implementation research. Conclusion Building on extant qualitative research guidelines, we suggest that researchers anchor their approach to implementation in reflexivity, intentionally and iteratively reflecting on their own situatedness. Through this autoethnography, we have elucidated several strategies based on critical reflection including examining philosophical underpinnings of research, adopting restorative practices that align with one’s values, and embracing personal presence as a foundation of scientific productivity. Within the predominant (post-) positivism paradigms, autoethnography may be criticized as unscientifically subjective or self-indulgent. However, this work demonstrates that autoethnography is a vehicle for third-person observation and first-person critical reflection that is transformative in understanding and optimizing implementation contexts, processes, and outcomes.
Adrenocortical Challenge Response and Genomic Analyses in Scottish Terriers With Increased Alkaline Phosphate Activity
Zimmerman, Kurt L.; Panciera, David L.; Hoeschele, Ina; Monroe, William E.; Todd, S. Michelle; Werre, Stephen R.; LeRoith, Tanya; Fecteau, Kellie; Lake, Bathilda B. (Frontiers, 2018-10-09)
Scottish terriers (ST) frequently have increased serum alkaline phosphatase (ALP) of the steroid isoform. Many of these also have high serum concentrations of adrenal sex steroids. The study’s objective was to determine the cause of increased sex steroids in ST with increased ALP. Adrenal gland suppression and stimulation were compared by low dose dexamethasone (LDDS), human chorionic gonadotropin (HCG) and adrenocorticotropic hormone (ACTH) response tests. Resting plasma pituitary hormones were measured. Steroidogenesis-related mRNA expression was evaluated in six ST with increased ALP, eight dogs of other breeds with pituitary-dependent hyperadrenocorticism (HAC), and seven normal dogs. The genome-wide association of single nucleotide polymorphisms (SNP) with ALP activity was evaluated in 168 ST. ALP (reference interval 8–70 U/L) was high in all ST (1,054 U/L) and HAC (985 U/L) dogs. All HAC dogs and 2/8 ST had increased cortisol post-ACTH administration. All ST and 2/7 Normal dogs had increased sex steroids post-ACTH. ST and Normal dogs had similar post-challenge adrenal steroid profiles following LDDS and HCG. Surprisingly, mRNA of hydroxysteroid 17-beta dehydrogenase 2 (HSD17B2) was lower in ST and Normal dogs than HAC. HSD17B2 facilities metabolism of sex steroids. A SNP region was identified on chromosome 5 in proximity to HSD17B2 that correlated with increased serum ALP. ST in this study with increased ALP had a normal pituitary-adrenal axis in relationship to glucocorticoids and luteinizing hormone.We speculate the identified SNP and HSD17B2 gene may have a role in the pathogenesis of elevated sex steroids and ALP in ST.
Adult piping plover habitat selection varies by behavior
Robinson, Samantha; Bellman, Henrietta; Walker, Katie; Catlin, Daniel; Karpanty, Sarah M.; Ritter, Shannon; Fraser, James (Wiley Periodicals LLC, 2021-12)
Piping plovers (Charadrius melodus, “plover”) are beach-nesting shorebirds that occupy their breeding range from about April to August. When plovers arrive on the breeding grounds, they select and defend territories, lay and incubate eggs, and tend to precocial broods; additionally, adults can return to a non-breeding stage after final nest failure or after chicks have fledged or died. We hypothesized that habitat selection would differ among these phases of the breeding cycle because the needs of the birds differ among them. We monitored plovers on Fire Island and Westhampton Island, New York, during 2016– 2018, recording individual locations of adult birds. We used resource selection functions to determine whether breeding stage (pre-breeding, nesting, brooding, post-breeding), breeding status (breeding, nonbreeding), or instantaneous behavior class (parental [incubating, brooding, and accompanying chicks], non-parental [all other behaviors]) best explained relationships with landscape characteristics known to be important to breeding plovers. Differences in habitat selection between adults exhibiting parental behaviors and non-parental behaviors had the greatest support in our model set. Compared with non-parental plovers, plovers displaying parental behavior selected areas closer to bay intertidal habitats and with proportionally more dry sand in the surrounding landscape than other habitat types. Non-parental plovers avoided areas with more dry sand and did not select for or against bay intertidal habitats. Additionally, non-parental plovers avoided development and higher elevation areas more than parental plovers, although both exhibited avoidance of these features. The total amount of suitable habitat ranged from 100.14 ha to 151.07 ha. In each year, there was more suitable habitat for parental plovers (129.57–151.07 ha) than non-parental plovers (100.14–108.83 ha). Due to these differences, when improving, creating, and protecting plover habitat, managers should consider habitat needs of both behavioral classes. Habitat management for nesting and brooding plovers should focus on maintaining vegetation-free sand and access to foraging habitat, and habitat management for non-parental plovers should focus on flat, low-elevation foraging habitats, particularly areas further from development.
Advances in Behavioral Remote Data Collection in the Home Setting: Assessing the Mother-Infant Relationship and Infant's Adaptive Behavior via Virtual Visits
Shin, Eunkyung; Smith, Cynthia L.; Howell, Brittany R. (Frontiers, 2021-10-01)
Psychological science is struggling with moving forward in the midst of the COVID-19 pandemic, especially due to the halting of behavioral data collection in the laboratory. Safety barriers to assessing psychological behavior in person increased the need for remote data collection in natural settings. In response to these challenges, researchers, including our team, have utilized this time to advance remote behavioral methodology. In this article, we provide an overview of our group’s strategies for remote data collection methodology and examples from our research in collecting behavioral data in the context of psychological functioning. Then, we describe the design and development of our strategies for remote data collection of mother-infant interactions, with the goal being to assess maternal sensitivity and intrusiveness, as well as infants’ adaptive behaviors in several developmental domains. During these virtual visits over Zoom, mother-infant dyads watched a book-reading video and were asked to participate in peek-a-boo, toy play, and toy removal tasks. After the behavioral tasks, a semi-structured interview (Vineland Adaptive Behavior Scale – VABS III) was conducted to assess the infant’s adaptive behavior in communication, socialization, daily living skills, and motor domains. We delineate the specific strategies we applied to integrate laboratory tasks and a semi-structured interview into remote data collection in home settings with mothers and infants. We also elaborate on issues encountered during remote data collection and how we resolved these challenges. Lastly, to inform protocols for future remote data collection, we address considerations and recommendations, as well as benefits and future directions for behavioral researchers in developmental psychology research.
Advances in Nutrition Science and Integrative Physiology: Insights From Controlled Feeding Studies
Davy, Kevin P.; Davy, Brenda M. (Frontiers, 2019-10-29)
Nutrition science is a highly impactful but contentious area of biomedical science. Establishing cause and effect relationships between the nutrients and/or diets we consume and the avoidance of or risk of disease is extremely challenging. As such, evidence-based nutrition is best served by considering the totality of evidence across multiple study types including nutritional epidemiological studies, randomized controlled trials of behavioral interventions, and controlled feeding studies. The purpose of the present review is to provide an overview for those conducting research outside of clinical nutrition on how controlled feeding studies can be used to gain insight into integrative physiology/metabolism as well as to inform dietary guidelines. We discuss the rationale, basic elements, and complexities of conducting controlled feeding studies and provide examples of contributions of controlled feeding studies to advances in nutrition science and integrative physiology. Our goal is to provide a resource for those wishing to leverage the experimental advantage provided by controlled feeding studies in their own research programs.
Aerial high-throughput phenotyping of peanut leaf area index and lateral growth
Sarkar, Sayantan; Cazenave, Alexandre-Brice; Oakes, Joseph C.; McCall, David S.; Thomason, Wade E.; Abbott, A. Lynn; Balota, Maria (Springer Nature, 2021-11-04)
Leaf area index (LAI) is the ratio of the total one-sided leaf area to the ground area, whereas lateral growth (LG) is the measure of canopy expansion. They are indicators for light capture, plant growth, and yield. Although LAI and LG can be directly measured, this is time consuming. Healthy leaves absorb in the blue and red, and reflect in the green regions of the electromagnetic spectrum. Aerial high-throughput phenotyping (HTP) may enable rapid acquisition of LAI and LG from leaf reflectance in these regions. In this paper, we report novel models to estimate peanut (Arachis hypogaea L.) LAI and LG from vegetation indices (VIs) derived relatively fast and inexpensively from the red, green, and blue (RGB) leaf reflectance collected with an unmanned aerial vehicle (UAV). In addition, we evaluate the models’ suitability to identify phenotypic variation for LAI and LG and predict pod yield from early season estimated LAI and LG. The study included 18 peanut genotypes for model training in 2017, and 8 genotypes for model validation in 2019. The VIs included the blue green index (BGI), red-green ratio (RGR), normalized plant pigment ratio (NPPR), normalized green red difference index (NGRDI), normalized chlorophyll pigment index (NCPI), and plant pigment ratio (PPR). The models used multiple linear and artificial neural network (ANN) regression, and their predictive accuracy ranged from 84 to 97%, depending on the VIs combinations used in the models. The results concluded that the new models were time- and cost-effective for estimation of LAI and LG, and accessible for use in phenotypic selection of peanuts with desirable LAI, LG and pod yield.
Aesthetics of Otherness: Representation of #migrantcaravan and #caravanamigrante on Instagram
Rosa, Fernanda R.; Soto-Vasquez, Arthur D. (Sage, 2022-01)
This article examines the representation of the migrant caravan on Instagram showing how an aesthetics of otherness has prevailed in this representation. Aesthetics of otherness is the result of the interaction between platform users' selections and platform affordances that creates a gap between the marginalized other and the user. Based on a qualitative content analysis of posts with the hashtags #caravanamigrante and #migrantcaravan, this research reveals that the two hashtags form parallel, although not alike, communicative spaces where migrant caravan representation is mostly mediated by professionals and organizations interested in promoting their own work and not by the migrants themselves. Despite this trend, users posting with #caravanamigrante were less likely to hijack the intent of the public, more likely to reference reasons for migration, and overall less likely to employ the aesthetics of otherness, which point to the possibility of circumventing the role of the platform in shaping the representation of marginalized people and social justice movements.
Age, but Not Sex, Modulates Foxp3 Expression in the Rat Brain across Development
Taylor, Makenzlie R.; Roby, Clinton R.; Elziny, Soad; Duricy, Erin; Taylor, Tina M.; Bowers, J. Michael (Elsevier, 2020)
The interconnectivity between brain development and the immune system has become an area of interest for many neuroscientists. However, to date, a limited number of known immune mediators of the peripheral nervous system (PNS) have been found to influence the development of the central nervous system (CNS). FOXP3 is a well-established mediator of regulatory T-cells in the PNS. However, the expression pattern of FOXP3 in the CNS and the PNS throughout development is unknown. To fill this void, we have characterized, in several brain regions, the developmental profile of Foxp3 for both sexes using rats. We found different patterns of Foxp3 in the CNS and PNS. In the CNS, we found Foxp3 was ubiquitously expressed, with the levels of Foxp3 varying by brain region. We also found both Foxp3 mRNA and protein levels peak during embryonic development and then steadily decrease with a peak increase during adulthood. In adulthood, the protein but not mRNA increases to the equivalent levels found at the embryonic stage of life. In the PNS, Foxp3 protein levels were low embryonically and increased steadily over the life of the animal with maximal levels reached in adulthood. Patterns observed for both the PNS and CNS were similar in males and females across all developmental timepoints. Our novel findings have implications for understanding how the neural immune system impacts neurodevelopmental disorders such as autism and schizophrenia.
Age-related strength loss affects non-stepping balance recovery
Koushyar, Hoda; Bieryla, Kathleen A.; Nussbaum, Maury A.; Madigan, Michael L. (Public Library of Science, 2019-01-18)
Aging is associated with a higher risk of falls, and an impaired ability to recover balance after a postural perturbation is an important contributing factor. In turn, this impaired recovery ability likely stems from age-related decrements in lower limb strength. The purpose of this study was to investigate the effects of age-related strength loss on non-stepping balance recovery capability after a perturbation while standing, without constraining movements to the ankle as in prior reports. Two experiments were conducted. In the first, five young adults (ages 20–30) and six community-dwelling older adults (ages 70–80) recovered their balance, without stepping, from a backward displacement of a support surface. Balance recovery capability was quantified as the maximal backward platform displacement that a subject could withstand without stepping. The maximal platform displacement was 27% smaller among the older group (11.8±2.1 cm) vs. the young group (16.2±2.6 cm). In the second experiment, forward dynamic simulations of a two-segment, rigid-body model were used to investigate the effects of manipulating strength in the hip extensors/flexors and ankle plantar flexors/dorsiflexors. In these, typical age-related reductions in strength were included. The model predicted lower maximal platform displacements with age-related reductions only in plantar flexion and hip flexion strength. These findings support the previously reported age-related loss of balance recovery ability, and an important role for plantar flexor strength in this ability. © 2019 Koushyar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Aggregated responses of human mobility to severe winter storms: An empirical study
Wang, Yan; Wang, Qi; Taylor, John E. (PLOS, 2017-12-07)
Increasing frequency of extreme winter storms has resulted in costly damages and a disruptive impact on the northeastern United States. It is important to understand human mobility patterns during such storms for disaster preparation and relief operations. We investigated the effects of severe winter storms on human mobility during a 2015 blizzard using 2.69 million Twitter geolocations. We found that displacements of different trip distances and radii of gyration of individuals' mobility were perturbed significantly. We further explored the characteristics of perturbed mobility during the storm, and demonstrated that individuals' recurrent mobility does not have a higher degree of similarity with their perturbed mobility, when comparing with its similarity to non-perturbed mobility. These empirical findings on human mobility impacted by severe winter storms have potential long-term implications on emergency response planning and the development of strategies to improve resilience in severe winter storms.
Air Quality in Southeast Brazil during COVID-19 Lockdown: A Combined Satellite and Ground-Based Data Analysis
Brandao, Rayssa; Foroutan, Hosein (MDPI, 2021-05-01)
With the current COVID-19 pandemic being spread all over the world, lockdown measures are being implemented, making air pollution levels go down in several countries. In this context, the air quality changes in the highly populated and trafficked Brazilian states of São Paulo (SP) and Rio de Janeiro (RJ) were addressed using a combination of satellite and ground-based daily data analysis. We explored nitrogen dioxide (NO2) and fine particulate matter (PM2.5) daily levels for the month of May from 2015–2020. Daily measurements of NO2 column concentrations from the Ozone Monitoring Instrument (OMI) aboard NASA’s Aura satellite were analyzed and decreases of 42% and 49.6% were found for SP and RJ, respectively, during the year 2020 compared to the 2015–2019 average. Besides NO2 column retrievals, ground-based data measured by the Brazilian States Environmental Institutions were analyzed and correlated with satellite retrievals. Correlation coefficients between year-to-year changes in satellite column and ground-based concentrations were 77% and 53% in SP and RJ, respectively. Ground-based data showed 13.3% and 18.8% decrease in NO2 levels for SP and RJ, respectively, in 2020 compared to 2019. In SP, no significant change in PM2.5 was observed in 2020 compared to 2019. To further isolate the effect of emissions reduction due to the lockdown, meteorological data and number of wildfire hotspots were analyzed. NO2 concentrations showed negative and positive correlations with wind speed and temperature, respectively. PM2.5 concentration distributions suggested an influence by the wildfires in the southeast region of the country. Synergistic analyses of satellite retrievals, surface level concentrations, and weather data provide a more complete picture of changes to pollutant levels.

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