54 research outputs found
Biochemical and physiological adjustments in common bermudagrass (Cynodon dactylon [L.] Pers.) and tall fescue (Festuca arundinacea Schreb.) under low temperature stress
Low temperature is a restrictive factor for turfgrass growth and development in temperate regions. A study was conducted with the purpose of examining the physiological and antioxidant response of two turf species, Festuca arundinacea Schreb. ‘Starlett’ and Cynodon dactylon [L.] Pers. ‘California Origin’ to cold stress in a growth chamber at the College of Agriculture, Shiraz University. Five temperatures (25, 15, 7.5, 0 and -7.5°C) in four replicates were examined in a completely randomized design experiment. It was revealed that under low temperature stress, soluble sugar contents, proline, malondialdehyde (MDA) and hydrogen peroxide (H2O2) were increased in both turfgrasses. Antioxidant enzyme activity, particularly catalase (CAT, EC 1.11.1.6) and superoxide dismutase (SOD, EC 1.15.1.1), was increased as a result of temperature reduction from 25°C to 0°C. Tall fescue is thought to be better adapted to cold stress than common bermudagrass due to higher soluble sugar contents, proline, malondialdehyde and antioxidant enzyme activity. The results show that scavenging enzymes have a direct effect in cold season tolerance of turfgrass and improve the defense mechanism of plants, but their exact role merits further investigation
Deep Learning for Detection and Localization of B-Lines in Lung Ultrasound
Lung ultrasound (LUS) is an important imaging modality used by emergency
physicians to assess pulmonary congestion at the patient bedside. B-line
artifacts in LUS videos are key findings associated with pulmonary congestion.
Not only can the interpretation of LUS be challenging for novice operators, but
visual quantification of B-lines remains subject to observer variability. In
this work, we investigate the strengths and weaknesses of multiple deep
learning approaches for automated B-line detection and localization in LUS
videos. We curate and publish, BEDLUS, a new ultrasound dataset comprising
1,419 videos from 113 patients with a total of 15,755 expert-annotated B-lines.
Based on this dataset, we present a benchmark of established deep learning
methods applied to the task of B-line detection. To pave the way for
interpretable quantification of B-lines, we propose a novel "single-point"
approach to B-line localization using only the point of origin. Our results
show that (a) the area under the receiver operating characteristic curve ranges
from 0.864 to 0.955 for the benchmarked detection methods, (b) within this
range, the best performance is achieved by models that leverage multiple
successive frames as input, and (c) the proposed single-point approach for
B-line localization reaches an F1-score of 0.65, performing on par with the
inter-observer agreement. The dataset and developed methods can facilitate
further biomedical research on automated interpretation of lung ultrasound with
the potential to expand the clinical utility.Comment: 10 pages, 4 figure
The Scales Project, a cross-national dataset on the interpretation of thermal perception scales
Thermal discomfort is one of the main triggers for occupants' interactions with components of the built environment such as adjustments of thermostats and/or opening windows and strongly related to the energy use in buildings. Understanding causes for thermal (dis-)comfort is crucial for design and operation of any type of building. The assessment of human thermal perception through rating scales, for example in post-occupancy studies, has been applied for several decades; however, long-existing assumptions related to these rating scales had been questioned by several researchers. The aim of this study was to gain deeper knowledge on contextual influences on the interpretation of thermal perception scales and their verbal anchors by survey participants. A questionnaire was designed and consequently applied in 21 language versions. These surveys were conducted in 57 cities in 30 countries resulting in a dataset containing responses from 8225 participants. The database offers potential for further analysis in the areas of building design and operation, psycho-physical relationships between human perception and the built environment, and linguistic analyses
Evaluating assumptions of scales for subjective assessment of thermal environments – Do laypersons perceive them the way, we researchers believe?
People's subjective response to any thermal environment is commonly investigated by using rating scales describing the degree of thermal sensation, comfort, and acceptability. Subsequent analyses of results collected in this way rely on the assumption that specific distances between verbal anchors placed on the scale exist and that relationships between verbal anchors from different dimensions that are assessed (e.g. thermal sensation and comfort) do not change. Another inherent assumption is that such scales are independent of the context in which they are used (climate zone, season, etc.). Despite their use worldwide, there is indication that contextual differences influence the way the scales are perceived and therefore question the reliability of the scales’ interpretation. To address this issue, a large international collaborative questionnaire study was conducted in 26 countries, using 21 different languages, which led to a dataset of 8225 questionnaires. Results, analysed by means of robust statistical techniques, revealed that only a subset of the responses are in accordance with the mentioned assumptions. Significant differences appeared between groups of participants in their perception of the scales, both in relation to distances of the anchors and relationships between scales. It was also found that respondents’ interpretations of scales changed with contextual factors, such as climate, season, and language. These findings highlight the need to carefully consider context-dependent factors in interpreting and reporting results from thermal comfort studies or post-occupancy evaluations, as well as to revisit the use of rating scales and the analysis methods used in thermal comfort studies to improve their reliability
The Scales Project, a cross-national dataset on the interpretation of thermal perception scales
Thermal discomfort is one of the main triggers for occupants’ interactions with components of the built environment such as adjustments of thermostats and/or opening windows and strongly related to the energy use in buildings. Understanding causes for thermal (dis-)comfort is crucial for design and operation of any type of building. The assessment of human thermal perception through rating scales, for example in post-occupancy studies, has been applied for several decades; however, long-existing assumptions related to these rating scales had been questioned by several researchers. The aim of this study was to gain deeper knowledge on contextual influences on the interpretation of thermal perception scales and their verbal anchors by survey participants. A questionnaire was designed and consequently applied in 21 language versions. These surveys were conducted in 57 cities in 30 countries resulting in a dataset containing responses from 8225 participants. The database offers potential for further analysis in the areas of building design and operation, psycho-physical relationships between human perception and the built environment, and linguistic analyses
The global decline of cheetah Acinonyx jubatus and what it means for conservation
Establishing and maintaining protected areas (PAs) are key tools for biodiversity conservation. However, this approach is insufficient for many species, particularly those that are wide-ranging and sparse. The cheetah Acinonyx jubatus exemplifies such a species and faces extreme challenges to its survival. Here, we show that the global population is estimated at ∼7,100 individuals and confined to 9% of its historical distributional range. However, the majority of current range (77%) occurs outside of PAs, where the species faces multiple threats. Scenario modeling shows that, where growth rates are suppressed outside PAs, extinction rates increase rapidly as the proportion of population protected declines. Sensitivity analysis shows that growth rates within PAs have to be high if they are to compensate for declines outside. Susceptibility of cheetah to rapid decline is evidenced by recent rapid contraction in range, supporting an uplisting of the International Union for the Conservation of Nature (IUCN) Red List threat assessment to endangered. Our results are applicable to other protection-reliant species, which may be subject to systematic underestimation of threat when there is insufficient information outside PAs. Ultimately, conserving many of these species necessitates a paradigm shift in conservation toward a holistic approach that incentivizes protection and promotes sustainable human–wildlife coexistence across large multiple-use landscapes
Waterborne hyperbranched alkyd-acrylic resin obtained by miniemulsion polymerization
Abstract Four waterborne hyperbranched alkyd-acrylic resins (HBRAA) were synthesized by miniemulsion polymerization from a hyperbranched alkyd resin (HBR), methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA), by using benzoyl peroxide (BPO) and ammonium persulfate (AP) as initiators. The reaction between HBR and acrylic monomers was evidenced by differential scanning calorimetric (DSC), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The conversion percentage, glass transition temperature (Tg), content of acrylic polymer (determined by soxhlet extraction) and molecular weight increased with the content of acrylic monomers used in the synthesis. The main structure formed during the synthesis was the HBRAA. The analysis by dynamic light scattering (DLS) showed that the particle size distribution of HBRAA2, HBRAA3 and HBRAA4 resins were mainly monomodal. The film properties (gloss, flexibility, adhesion and drying time) of the HBRAA were good
Cold Tolerance and Antioxidant Response of Poa Pratensis and Paspalum vaginatum
A limiting factor for prodution of turf grasses in temperate regions is their low level of cold tolerance. In order to elucidate the cold tolerance, physiological and biochemical responses of two turf species, this study was conducted at a controlled environment greenhouse of Faculty of Agriculture in Shiraz University, Shiraz, Iran by a factorial experiment in completely randomized design with three replicates. Factors consisted of two turf species including Kentucky bluegrass (Poa pratensis) and seashore paspalum (Paspalum vaginatum) and four temperatures: 25, 15, 5 and -5 °C. Data analysis revealed that decreased temperature resulted in significant increases in proline, soluble sugars contents and activity of peroxidase, ascorbate peroxidase, catalase and superoxide dismutase enzymes, although seashore paspalum indicated a significant drop in antioxidant enzymes activity at cold stress of -5 °C. Furthermore, decreased temperature brought about a significant decline in visual quality, chlorophyll, starch and relative water content. Seashore paspalum exhibited a greater deterioration in visual quality, chlorophyll and relative water content at -5 °C compared to Kentucky bluegrass. The results showed that Kentucky bluegrass withstood cold stress with a better and more efficient defensive mechanism in comparison with seashore paspalum, thus it is considered more tolerant to cold stress and could, potentially, be used in temperate regions
The critically endangered Asiatic cheetah Acinonyx jubatus venaticus in Iran: a review of recent distribution, and conservation status
Considerable effort has been put into conservation of the critically endangered Asiatic cheetah Acinonyx jubatus venaticus in Iran during the past few decades, and a thorough review of the species’ status, demography, range and conservation is provided here. We collated a large dataset of all verified occurrence data, photographic records and mortality cases since 1980 throughout the species’ range in Iran. Currently, the cheetah is distributed throughout the arid landscapes of the eastern half of Iran, but the limits of its current and past range as well as population trends are uncertain. Surveys of nearly 40 different areas resulted in 18 localities with confirmed presence of cheetahs in recent years. Camera trapping has been an effective tool to provide evidence of presence and status of cheetahs, revealing the species’ extremely low density and long inter-reserve movements. Together with photographic records, a total of 82 different cheetahs were detected during the 2000s in Iran. Protection status in most areas has been elevated by the Iran government. Asiatic cheetahs are highly vulnerable to extinction, mainly due to causalities mediated by herder persecution, poaching and road collisions as well as prey and habitat loss. Some efforts have been made to address these threats, but range expansion in recent years is a result of greater survey effort, rather than population recovery. We suggest that, despite conservation investment of the last 15 years, the species remains critically endangered on the verge of extinction
The critically endangered Asiatic cheetah Acinonyx jubatus venaticus in Iran: a review of recent distribution, and conservation status
Considerable effort has been put into conservation of the critically endangered Asiatic cheetah Acinonyx jubatus venaticus in Iran during the past few decades, and a thorough review of the species’ status, demography, range and conservation is provided here. We collated a large dataset of all verified occurrence data, photographic records and mortality cases since 1980 throughout the species’ range in Iran. Currently, the cheetah is distributed throughout the arid landscapes of the eastern half of Iran, but the limits of its current and past range as well as population trends are uncertain. Surveys of nearly 40 different areas resulted in 18 localities with confirmed presence of cheetahs in recent years. Camera trapping has been an effective tool to provide evidence of presence and status of cheetahs, revealing the species’ extremely low density and long inter-reserve movements. Together with photographic records, a total of 82 different cheetahs were detected during the 2000s in Iran. Protection status in most areas has been elevated by the Iran government. Asiatic cheetahs are highly vulnerable to extinction, mainly due to causalities mediated by herder persecution, poaching and road collisions as well as prey and habitat loss. Some efforts have been made to address these threats, but range expansion in recent years is a result of greater survey effort, rather than population recovery. We suggest that, despite conservation investment of the last 15 years, the species remains critically endangered on the verge of extinction
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