Impact of cadmium on forage kale (Brassica oleracea var. viridis cv "Prover") after 3-,10- and 56-day exposure to a Cd-spiked field soil.

PubMed

Bernard, Fabien; Dumez, Sylvain; Lemière, Sébastien; Platel, Anne; Nesslany, Fabrice; Deram, Annabelle; Vandenbulcke, Franck; Cuny, Damien

2018-03-15

Cadmium (Cd) is a highly toxic element for living organisms and is widespread in metal-contaminated soils. As organisms which can grow up on these polluted areas, plants have some protection mechanisms against Cd issues. Among the plant kingdom, the Brassicaceae family includes species which are known to be able to tolerate and accumulate Cd in their tissues. In this study, Brassica oleracea var. viridis cv "Prover" was exposed to a range of artificially Cd-contaminated soils (from 2.5 up to 20 mg kg -1 ) during 3, 10, and 56 days and the effects on life traits, photosynthesis activity, antioxidant enzymatic activities were studied. Metal accumulation was quantified, as well as DNA damage, by means of the comet assay and immunodetection of 8-OHdG levels. Globally, B. oleracea was relatively tolerant to those Cd exposures. However, comet assay and detection of 8-OHdG revealed some DNA damage but which are not significant. According to metal accumulation analysis, B. oleracea var. viridis cv Prover could be a good candidate for alternative growing in contaminated areas.

Monitoring Strategies for REDD+: Integrating Field, Airborne, and Satellite Observations of Amazon Forests

NASA Technical Reports Server (NTRS)

Morton, Douglas; Souza, Carlos, Jr.; Souza, Carlos, Jr.; Keller, Michael

2012-01-01

Large-scale tropical forest monitoring efforts in support of REDD+ (Reducing Emissions from Deforestation and forest Degradation plus enhancing forest carbon stocks) confront a range of challenges. REDD+ activities typically have short reporting time scales, diverse data needs, and low tolerance for uncertainties. Meeting these challenges will require innovative use of remote sensing data, including integrating data at different spatial and temporal resolutions. The global scientific community is engaged in developing, evaluating, and applying new methods for regional to global scale forest monitoring. Pilot REDD+ activities are underway across the tropics with support from a range of national and international groups, including SilvaCarbon, an interagency effort to coordinate US expertise on forest monitoring and resource management. Early actions on REDD+ have exposed some of the inherent tradeoffs that arise from the use of incomplete or inaccurate data to quantify forest area changes and related carbon emissions. Here, we summarize recent advances in forest monitoring to identify and target the main sources of uncertainty in estimates of forest area changes, aboveground carbon stocks, and Amazon forest carbon emissions.

Marine ecosystem resilience during extreme deoxygenation: the Early Jurassic oceanic anoxic event.

PubMed

Caswell, Bryony A; Frid, Christopher L J

2017-01-01

Global warming during the Early Jurassic, and associated widespread ocean deoxygenation, was comparable in scale with the changes projected for the next century. This study quantifies the impact of severe global environmental change on the biological traits of marine communities that define the ecological roles and functions they deliver. We document centennial-millennial variability in the biological trait composition of Early Jurassic (Toarcian) seafloor communities and examine how this changed during the event using biological traits analysis. Environmental changes preceding the global oceanic anoxic event (OAE) produced an ecological shift leading to stressed benthic palaeocommunities with reduced resilience to the subsequent OAE. Changes in traits and ecological succession coincided with major environmental changes; and were of similar nature and magnitude to those in severely deoxygenated benthic communities today despite the very different timescales. Changes in community composition were linked to local redox conditions whereas changes in populations of opportunists were driven by primary productivity. Throughout most of the OAE substitutions by tolerant taxa conserved the trait composition and hence functioning, but periods of severe deoxygenation caused benthic defaunation that would have resulted in functional collapse. Following the OAE recovery was slow probably because the global nature of the event restricted opportunities for recruitment from outside the basin. Our findings suggest that future systems undergoing deoxygenation may initially show functional resilience, but severe global deoxygenation will impact traits and ecosystem functioning and, by limiting the species pool, will slow recovery rates.

Quantifying the Impact of Physical Activity on Stress Tolerance in College Students

ERIC Educational Resources Information Center

Bland, Helen W.; Melton, Bridget F.; Bigham, Lauren E.; Welle, Paul D.

2014-01-01

Problem: Stress experience by millennial college students can be crippling. While stress is a universal and unavoidable phenomenon for college students, the variance in ability to handle stress can be attributed to stress tolerance (Welle & Graf, 2011). Research is needed to identify effective tools that increase college students' ability to…

4. Carbon Changes in U.S. Forests

Treesearch

R.A. Birdsey; L.S. Heath

1995-01-01

Global concern about increasing atmospheric concentrations of greenhouse gases, particularly carbon dioxide (CO2), and the possible consequences of future climate changes, has generated interest in understanding and quantifying the role of terrestrial ecosystems in the global carbon cycle. Recent efforts to quantify the global carbon budget have...

Fault tolerant software modules for SIFT

NASA Technical Reports Server (NTRS)

Hecht, M.; Hecht, H.

1982-01-01

The implementation of software fault tolerance is investigated for critical modules of the Software Implemented Fault Tolerance (SIFT) operating system to support the computational and reliability requirements of advanced fly by wire transport aircraft. Fault tolerant designs generated for the error reported and global executive are examined. A description of the alternate routines, implementation requirements, and software validation are included.

IrrE, a Global Regulator of Extreme Radiation Resistance in Deinococcus radiodurans, Enhances Salt Tolerance in Escherichia coli and Brassica napus

PubMed Central

Zhou, Zhengfu; Yan, Yongliang; Zhang, Wei; Lu, Wei; Ping, Shuzhen; Dai, Qilin; Yuan, Menglong; Feng, Bin; Hou, Xiaoguang; Zhang, Ying; Ruiqiang; Liu, Tingting; Feng, Lu; Wang, Lei; Chen, Ming; Lin, Min

2009-01-01

Background Globally, about 20% of cultivated land is now affected by salinity. Salt tolerance is a trait of importance to all crops in saline soils. Previous efforts to improve salt tolerance in crop plants have met with only limited success. Bacteria of the genus Deinococcus are known for their ability to survive highly stressful conditions, and therefore possess a unique pool of genes conferring extreme resistance. In Deinococcus radiodurans, the irrE gene encodes a global regulator responsible for extreme radioresistance. Methodology/Principal Findings Using plate assays, we showed that IrrE protected E. coli cells against salt shock and other abiotic stresses such as oxidative, osmotic and thermal shocks. Comparative proteomic analysis revealed that IrrE functions as a switch to regulate different sets of proteins such as stress responsive proteins, protein kinases, glycerol-degrading enzymes, detoxification proteins, and growth-related proteins in E. coli. We also used quantitative RT-PCR to investigate expression of nine selected stress-responsive genes in transgenic and wild-type Brassica napus plants. Transgenic B. napus plants expressing the IrrE protein can tolerate 350 mM NaCl, a concentration that inhibits the growth of almost all crop plants. Conclusions Expression of IrrE, a global regulator for extreme radiation resistance in D. radiodurans, confers significantly enhanced salt tolerance in both E. coli and B. napus. We thus propose that the irrE gene might be used as a potentially promising transgene to improve abiotic stress tolerances in crop plants. PMID:19204796

Quantitative proteomic analysis of two different rice varieties reveals that drought tolerance is correlated with reduced abundance of photosynthetic machinery and increased abundance of ClpD1 protease.

PubMed

Wu, Yunqi; Mirzaei, Mehdi; Pascovici, Dana; Chick, Joel M; Atwell, Brian J; Haynes, Paul A

2016-06-30

Rice is the major staple food for more than half of world's population. As global climate changes, we are observing more floods, droughts and severe heat waves. Two rice cultivars with contrasting genetic backgrounds and levels of tolerance to drought, Nipponbare and IAC1131, were used in this study. Four-week-old seedlings of both cultivars were grown in large soil volumes and then exposed to moderate and extreme drought for 7days, followed by 3days of re-watering. Mature leaves were harvested from plants from each treatment for protein extraction and subsequent shotgun proteomic analysis, with validation of selected proteins by western blotting. Gene Ontology (GO) annotations of differentially expressed proteins provide insights into the metabolic pathways that are involved in drought stress resistance. Our data indicate that IAC1131 appears to be better able to cope with stressful conditions by upregulating a suite of stress and defence response related proteins. Nipponbare, in contrast, lacks the range of stress responses shown by the more stress tolerant variety, and responds to drought stress by initiating a partial shutdown of chlorophyll biosynthesis in an apparent attempt to preserve resources. In this study, two rice genotypes with contrasting drought tolerance were exposed to soil water deficits, and proteomic changes were observed in mature leaf laminae. Plants were well watered and then switched to conditions of either moderate drought or extreme drought followed by three days of recovery. Proteins were identified and quantified using both label-free and Tandem Mass Tag multiplexing approaches. Several biochemical pathways were significantly altered in response to water deficit. Most notably, the up-regulation of ClpD1 protease responded strongly in the drought-tolerant landrace; this protein is typically involved in heat and osmotic stress response. In contrast, porphyrin and chlorophyll biosynthesis pathways were down-regulated, indicating suppression of the photosynthetic machinery. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantifying edge significance on maintaining global connectivity

PubMed Central

Qian, Yuhua; Li, Yebin; Zhang, Min; Ma, Guoshuai; Lu, Furong

2017-01-01

Global connectivity is a quite important issue for networks. The failures of some key edges may lead to breakdown of the whole system. How to find them will provide a better understanding on system robustness. Based on topological information, we propose an approach named LE (link entropy) to quantify the edge significance on maintaining global connectivity. Then we compare the LE with the other six acknowledged indices on the edge significance: the edge betweenness centrality, degree product, bridgeness, diffusion importance, topological overlap and k-path edge centrality. Experimental results show that the LE approach outperforms in quantifying edge significance on maintaining global connectivity. PMID:28349923

How Will Copper Contamination Constrain Future Global Steel Recycling?

PubMed

Daehn, Katrin E; Cabrera Serrenho, André; Allwood, Julian M

2017-06-06

Copper in steel causes metallurgical problems, but is pervasive in end-of-life scrap and cannot currently be removed commercially once in the melt. Contamination can be managed to an extent by globally trading scrap for use in tolerant applications and dilution with primary iron sources. However, the viability of long-term strategies can only be evaluated with a complete characterization of copper in the global steel system and this is presented in this paper. The copper concentration of flows along the 2008 steel supply chain is estimated from a survey of literature data and compared with estimates of the maximum concentration that can be tolerated in steel products. Estimates of final steel demand and scrap supply by sector are taken from a global stock-saturation model to determine when the amount of copper in the steel cycle will exceed that which can be tolerated. Best estimates show that quantities of copper arising from conventional scrap preparation can be managed in the global steel system until 2050 assuming perfectly coordinated trade and extensive dilution, but this strategy will become increasingly impractical. Technical and policy interventions along the supply chain are presented to close product loops before this global constraint.

Do Self-Interested Schooling Selections Improve Society? A Review of the Evidence

ERIC Educational Resources Information Center

DeAngelis, Corey A.

2017-01-01

I review the literature that quantifies the effects of private school choice programs on three important civic outcomes for students in the United States: tolerance, civic engagement, and social order. Out of the 11 studies on private school choice that examine these civic outcomes, the impacts are null to positive for tolerance, null to positive…

[Transgenic rice breeding for abiotic stress tolerance--present and future].

PubMed

Zhao, Feng-Yun; Zhang, Hui

2007-01-01

Environmental stresses and the continuing deterioration of arable land, along with an explosive increase in world population, pose serious threats to global agricultural production and food security. Improving the tolerance of the major crop plants to abiotic stresses has been a main goal in agriculture for a long time. As rice is considered one of the major crops, the development of new cultivars with enhanced abiotic stress-tolerance will undoubtedly have an important effect on global food production. The transgenic approach offers an attractive alternative to conventional techniques for the genetic improvement of rice cultivars. In recent years, an array of stress-related genes has already been transferred to rice to improve its resistance against abiotic stresses. Many transgenic rice plants with enhanced abiotic stress-tolerance have been obtained. This article focuses on the progress in the study of abiotic stress tolerance in transgenic rice breeding.

Analysis of Gene Expression and Physiological Responses in Three Mexican Maize Landraces under Drought Stress and Recovery Irrigation

PubMed Central

Hayano-Kanashiro, Corina; Calderón-Vázquez, Carlos; Ibarra-Laclette, Enrique; Herrera-Estrella, Luis; Simpson, June

2009-01-01

Background Drought is one of the major constraints for plant productivity worldwide. Different mechanisms of drought-tolerance have been reported for several plant species including maize. However, the differences in global gene expression between drought-tolerant and susceptible genotypes and their relationship to physiological adaptations to drought are largely unknown. The study of the differences in global gene expression between tolerant and susceptible genotypes could provide important information to design more efficient breeding programs to produce maize varieties better adapted to water limiting conditions. Methodology/Principal Findings Changes in physiological responses and gene expression patterns were studied under drought stress and recovery in three Mexican maize landraces which included two drought tolerant (Cajete criollo and Michoacán 21) and one susceptible (85-2) genotypes. Photosynthesis, stomatal conductance, soil and leaf water potentials were monitored throughout the experiment and microarray analysis was carried out on transcripts obtained at 10 and 17 days following application of stress and after recovery irrigation. The two tolerant genotypes show more drastic changes in global gene expression which correlate with different physiological mechanisms of adaptation to drought. Differences in the kinetics and number of up- and down-regulated genes were observed between the tolerant and susceptible maize genotypes, as well as differences between the two tolerant genotypes. Interestingly, the most dramatic differences between the tolerant and susceptible genotypes were observed during recovery irrigation, suggesting that the tolerant genotypes activate mechanisms that allow more efficient recovery after a severe drought. Conclusions/Significance A correlation between levels of photosynthesis and transcription under stress was observed and differences in the number, type and expression levels of transcription factor families were also identified under drought and recovery between the three maize landraces. Gene expression analysis suggests that the drought tolerant landraces have a greater capacity to rapidly modulate more genes under drought and recovery in comparison to the susceptible landrace. Modulation of a greater number of differentially expressed genes of different TF gene families is an important characteristic of the tolerant genotypes. Finally, important differences were also noted between the tolerant landraces that underlie different mechanisms of achieving tolerance. PMID:19888455

Applying a Dynamic Stomatal Optimization to Predict Shifts in the Functional Composition of Tropical Forests Under Increased Drought And CO2

NASA Astrophysics Data System (ADS)

Bartlett, M. K.; Detto, M.; Pacala, S. W.

2017-12-01

The accurate prediction of tropical forest carbon fluxes is key to forecasting global climate, but forest responses to projected increases in CO2 and drought are highly uncertain. Here we present a dynamic optimization that derives the trajectory of stomatal conductance (gs) during drought, a key source of model uncertainty, from plant and soil water relations and the carbon economy of the plant hydraulic system. This optimization scheme is novel in two ways. First, by accounting for the ability of capacitance (i.e., the release of water from plant storage tissue; C) to buffer evaporative water loss and maintain gs during drought, this optimization captures both drought tolerant and avoidant hydraulic strategies. Second, by determining the optimal trajectory of plant and soil water potentials, this optimization quantifies species' impacts on the water available to competing plants. These advances allowed us to apply this optimization across the range of physiology trait values observed in tropical species to evaluate shifts in the competitively optimal trait values, or evolutionarily stable hydraulic strategy (ESS), under increased drought and CO2. Increasing the length of the dry season shifted the ESS towards more drought tolerant, rather than avoidant, trait values, and these shifts were larger for longer individual drought periods (i.e., more consecutive days without rainfall), even if the total time spent in drought was the same. Concurrently doubling the CO2 level reduced the magnitude of these shifts and slightly favored drought avoidant strategies under wet conditions. Overall, these analyses predicted that short, frequent droughts would allow elevated CO2 to shift the functional composition in tropical forests towards more drought avoidant species, while infrequent but long drought periods would shift the ESS to more drought tolerant trait values, despite increased CO2. Overall, these analyses quantified the impact of physiology traits on plant performance and competitive ability, and provide a mechanistic, trait-based approach to predict shifts in the functional composition of tropical forests under projected climatic conditions.

Human group formation in online guilds and offline gangs driven by a common team dynamic.

PubMed

Johnson, Neil F; Xu, Chen; Zhao, Zhenyuan; Ducheneaut, Nicolas; Yee, Nicholas; Tita, George; Hui, Pak Ming

2009-06-01

Quantifying human group dynamics represents a unique challenge. Unlike animals and other biological systems, humans form groups in both real (offline) and virtual (online) spaces-from potentially dangerous street gangs populated mostly by disaffected male youths to the massive global guilds in online role-playing games for which membership currently exceeds tens of millions of people from all possible backgrounds, age groups, and genders. We have compiled and analyzed data for these two seemingly unrelated offline and online human activities and have uncovered an unexpected quantitative link between them. Although their overall dynamics differ visibly, we find that a common team-based model can accurately reproduce the quantitative features of each simply by adjusting the average tolerance level and attribute range for each population. By contrast, we find no evidence to support a version of the model based on like-seeking-like (i.e., kinship or "homophily").

Time distortion associated with smartphone addiction: Identifying smartphone addiction via a mobile application (App).

PubMed

Lin, Yu-Hsuan; Lin, Yu-Cheng; Lee, Yang-Han; Lin, Po-Hsien; Lin, Sheng-Hsuan; Chang, Li-Ren; Tseng, Hsien-Wei; Yen, Liang-Yu; Yang, Cheryl C H; Kuo, Terry B J

2015-06-01

Global smartphone penetration has brought about unprecedented addictive behaviors. We report a proposed diagnostic criteria and the designing of a mobile application (App) to identify smartphone addiction. We used a novel empirical mode decomposition (EMD) to delineate the trend in smartphone use over one month. The daily use count and the trend of this frequency are associated with smartphone addiction. We quantify excessive use by daily use duration and frequency, as well as the relationship between the tolerance symptoms and the trend for the median duration of a use epoch. The psychiatrists' assisted self-reporting use time is significant lower than and the recorded total smartphone use time via the App and the degree of underestimation was positively correlated with actual smartphone use. Our study suggests the identification of smartphone addiction by diagnostic interview and via the App-generated parameters with EMD analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Human group formation in online guilds and offline gangs driven by a common team dynamic

NASA Astrophysics Data System (ADS)

Johnson, Neil F.; Xu, Chen; Zhao, Zhenyuan; Ducheneaut, Nicolas; Yee, Nicholas; Tita, George; Hui, Pak Ming

2009-06-01

Quantifying human group dynamics represents a unique challenge. Unlike animals and other biological systems, humans form groups in both real (offline) and virtual (online) spaces—from potentially dangerous street gangs populated mostly by disaffected male youths to the massive global guilds in online role-playing games for which membership currently exceeds tens of millions of people from all possible backgrounds, age groups, and genders. We have compiled and analyzed data for these two seemingly unrelated offline and online human activities and have uncovered an unexpected quantitative link between them. Although their overall dynamics differ visibly, we find that a common team-based model can accurately reproduce the quantitative features of each simply by adjusting the average tolerance level and attribute range for each population. By contrast, we find no evidence to support a version of the model based on like-seeking-like (i.e., kinship or “homophily”).

Adaptive backstepping fault-tolerant control for flexible spacecraft with unknown bounded disturbances and actuator failures.

PubMed

Jiang, Ye; Hu, Qinglei; Ma, Guangfu

2010-01-01

In this paper, a robust adaptive fault-tolerant control approach to attitude tracking of flexible spacecraft is proposed for use in situations when there are reaction wheel/actuator failures, persistent bounded disturbances and unknown inertia parameter uncertainties. The controller is designed based on an adaptive backstepping sliding mode control scheme, and a sufficient condition under which this control law can render the system semi-globally input-to-state stable is also provided such that the closed-loop system is robust with respect to any disturbance within a quantifiable restriction on the amplitude, as well as the set of initial conditions, if the control gains are designed appropriately. Moreover, in the design, the control law does not need a fault detection and isolation mechanism even if the failure time instants, patterns and values on actuator failures are also unknown for the designers, as motivated from a practical spacecraft control application. In addition to detailed derivations of the new controller design and a rigorous sketch of all the associated stability and attitude error convergence proofs, illustrative simulation results of an application to flexible spacecraft show that high precise attitude control and vibration suppression are successfully achieved using various scenarios of controlling effective failures. 2009. Published by Elsevier Ltd.

Global variation in thermal tolerances and vulnerability of endotherms to climate change

PubMed Central

Khaliq, Imran; Hof, Christian; Prinzinger, Roland; Böhning-Gaese, Katrin; Pfenninger, Markus

2014-01-01

The relationships among species' physiological capacities and the geographical variation of ambient climate are of key importance to understanding the distribution of life on the Earth. Furthermore, predictions of how species will respond to climate change will profit from the explicit consideration of their physiological tolerances. The climatic variability hypothesis, which predicts that climatic tolerances are broader in more variable climates, provides an analytical framework for studying these relationships between physiology and biogeography. However, direct empirical support for the hypothesis is mostly lacking for endotherms, and few studies have tried to integrate physiological data into assessments of species' climatic vulnerability at the global scale. Here, we test the climatic variability hypothesis for endotherms, with a comprehensive dataset on thermal tolerances derived from physiological experiments, and use these data to assess the vulnerability of species to projected climate change. We find the expected relationship between thermal tolerance and ambient climatic variability in birds, but not in mammals—a contrast possibly resulting from different adaptation strategies to ambient climate via behaviour, morphology or physiology. We show that currently most of the species are experiencing ambient temperatures well within their tolerance limits and that in the future many species may be able to tolerate projected temperature increases across significant proportions of their distributions. However, our findings also underline the high vulnerability of tropical regions to changes in temperature and other threats of anthropogenic global changes. Our study demonstrates that a better understanding of the interplay among species' physiology and the geography of climate change will advance assessments of species' vulnerability to climate change. PMID:25009066

Insects at low pressure: applications to artificial ecosystems and implications for global windborne distribution

NASA Technical Reports Server (NTRS)

Cockell, C.; Catling, D.; Waites, H.

1999-01-01

Insects have a number of potential roles in closed-loop life support systems. In this study we examined the tolerance of a range of insect orders and life stages to drops in atmospheric pressure using a terrestrial atmosphere. We found that all insects studied could tolerate pressures down to 100 mb. No effects on insect respiration were noted down to 500 mb. Pressure toleration was not dependent on body volume. Our studies demonstrate that insects are compatible with plants in low-pressure artificial and closed-loop ecosystems. The results also have implications for arthropod colonization and global distribution on Earth.

Selective labelling and eradication of antibiotic-tolerant bacterial populations in Pseudomonas aeruginosa biofilms

PubMed Central

Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang; Adav, Sunil S.; Salido, May Margarette; Liu, Yang; Givskov, Michael; Sze, Siu Kwan; Tolker-Nielsen, Tim; Yang, Liang

2016-01-01

Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a ‘last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates research avenues for designing more efficient treatments against biofilm-associated infections. PMID:26892159

Selective labelling and eradication of antibiotic-tolerant bacterial populations in Pseudomonas aeruginosa biofilms.

PubMed

Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang; Adav, Sunil S; Salido, May Margarette; Liu, Yang; Givskov, Michael; Sze, Siu Kwan; Tolker-Nielsen, Tim; Yang, Liang

2016-02-19

Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a 'last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates research avenues for designing more efficient treatments against biofilm-associated infections.

Breeding for plant heat tolerance at vegetative and reproductive stages.

PubMed

Driedonks, Nicky; Rieu, Ivo; Vriezen, Wim H

2016-06-01

Thermotolerant crop research. Global warming has become a serious worldwide threat. High temperature is a major environmental factor limiting crop productivity. Current adaptations to high temperature via alterations to technical and management systems are insufficient to sustain yield. For this reason, breeding for heat-tolerant crops is in high demand. This review provides an overview of the effects of high temperature on plant physiology, fertility and crop yield and discusses the strategies for breeding heat-tolerant cultivars. Generating thermotolerant crops seems to be a challenging task as heat sensitivity is highly variable across developmental stages and processes. In response to heat, plants trigger a cascade of events, switching on numerous genes. Although breeding has made substantial advances in developing heat-tolerant lines, the genetic basis and diversity of heat tolerance in plants remain largely unknown. The development of new varieties is expensive and time-consuming, and knowledge of heat tolerance mechanisms would aid the design of strategies to screen germplasm for heat tolerance traits. However, gains in heat tolerance are limited by the often narrow genetic diversity. Exploration and use of wild relatives and landraces in breeding can increase useful genetic diversity in current crops. Due to the complex nature of plant heat tolerance and its immediate global concern, it is essential to face this breeding challenge in a multidisciplinary holistic approach involving governmental agencies, private companies and academic institutions.

Improving furfural tolerance of Zymomonas mobilis by rewiring a sigma factor RpoD protein.

PubMed

Tan, Fu-Rong; Dai, Li-Chun; Wu, Bo; Qin, Han; Shui, Zong-Xia; Wang, Jing-Li; Zhu, Qi-Li; Hu, Qi-Chun; Ruan, Zhi-Yong; He, Ming-Xiong

2015-06-01

Furfural from lignocellulosic hydrolysates is the key inhibitor for bio-ethanol fermentation. In this study, we report a strategy of improving the furfural tolerance in Zymomonas mobilis on the transcriptional level by engineering its global transcription sigma factor (σ(70), RpoD) protein. Three furfural tolerance RpoD mutants (ZM4-MF1, ZM4-MF2, and ZM4-MF3) were identified from error-prone PCR libraries. The best furfural-tolerance strain ZM4-MF2 reached to the maximal cell density (OD600) about 2.0 after approximately 30 h, while control strain ZM4-rpoD reached its highest cell density of about 1.3 under the same conditions. ZM4-MF2 also consumed glucose faster and yield higher ethanol; expression levels and key Entner-Doudoroff (ED) pathway enzymatic activities were also compared to control strain under furfural stress condition. Our results suggest that global transcription machinery engineering could potentially be used to improve stress tolerance and ethanol production in Z. mobilis.

Water velocity tolerance in tadpoles of the foothill yellow-legged frog (Rana boylii): Swimming performance, growth, and survival

Treesearch

S. Kupferberg; A. Lind; V. Thill; S. Yarnell

2011-01-01

We explored the effects of large magnitude flow fluctuations in rivers with dams, commonly referred to as pulsed flows, on tadpoles of the lotic-breeding Foothill Yellow-legged Frog, Rana boylii. We quantified the velocity conditions in habitats occupied by tadpoles and then conducted experiments to assess the tolerance to values at the upper limit...

Global error estimation based on the tolerance proportionality for some adaptive Runge-Kutta codes

NASA Astrophysics Data System (ADS)

Calvo, M.; González-Pinto, S.; Montijano, J. I.

2008-09-01

Modern codes for the numerical solution of Initial Value Problems (IVPs) in ODEs are based in adaptive methods that, for a user supplied tolerance [delta], attempt to advance the integration selecting the size of each step so that some measure of the local error is [similar, equals][delta]. Although this policy does not ensure that the global errors are under the prescribed tolerance, after the early studies of Stetter [Considerations concerning a theory for ODE-solvers, in: R. Burlisch, R.D. Grigorieff, J. Schröder (Eds.), Numerical Treatment of Differential Equations, Proceedings of Oberwolfach, 1976, Lecture Notes in Mathematics, vol. 631, Springer, Berlin, 1978, pp. 188-200; Tolerance proportionality in ODE codes, in: R. März (Ed.), Proceedings of the Second Conference on Numerical Treatment of Ordinary Differential Equations, Humbold University, Berlin, 1980, pp. 109-123] and the extensions of Higham [Global error versus tolerance for explicit Runge-Kutta methods, IMA J. Numer. Anal. 11 (1991) 457-480; The tolerance proportionality of adaptive ODE solvers, J. Comput. Appl. Math. 45 (1993) 227-236; The reliability of standard local error control algorithms for initial value ordinary differential equations, in: Proceedings: The Quality of Numerical Software: Assessment and Enhancement, IFIP Series, Springer, Berlin, 1997], it has been proved that in many existing explicit Runge-Kutta codes the global errors behave asymptotically as some rational power of [delta]. This step-size policy, for a given IVP, determines at each grid point tn a new step-size hn+1=h(tn;[delta]) so that h(t;[delta]) is a continuous function of t. In this paper a study of the tolerance proportionality property under a discontinuous step-size policy that does not allow to change the size of the step if the step-size ratio between two consecutive steps is close to unity is carried out. This theory is applied to obtain global error estimations in a few problems that have been solved with the code Gauss2 [S. Gonzalez-Pinto, R. Rojas-Bello, Gauss2, a Fortran 90 code for second order initial value problems, ], based on an adaptive two stage Runge-Kutta-Gauss method with this discontinuous step-size policy.

Tolerance adaptation and precipitation changes complicate latitudinal patterns of climate change impacts.

PubMed

Bonebrake, Timothy C; Mastrandrea, Michael D

2010-07-13

Global patterns of biodiversity and comparisons between tropical and temperate ecosystems have pervaded ecology from its inception. However, the urgency in understanding these global patterns has been accentuated by the threat of rapid climate change. We apply an adaptive model of environmental tolerance evolution to global climate data and climate change model projections to examine the relative impacts of climate change on different regions of the globe. Our results project more adverse impacts of warming on tropical populations due to environmental tolerance adaptation to conditions of low interannual variability in temperature. When applied to present variability and future forecasts of precipitation data, the tolerance adaptation model found large reductions in fitness predicted for populations in high-latitude northern hemisphere regions, although some tropical regions had comparable reductions in fitness. We formulated an evolutionary regional climate change index (ERCCI) to additionally incorporate the predicted changes in the interannual variability of temperature and precipitation. Based on this index, we suggest that the magnitude of climate change impacts could be much more heterogeneous across latitude than previously thought. Specifically, tropical regions are likely to be just as affected as temperate regions and, in some regions under some circumstances, possibly more so.

Assessment of the salt tolerance and environmental biosafety of Eucalyptus camaldulensis harboring a mangrin transgene.

PubMed

Yu, Xiang; Kikuchi, Akira; Shimazaki, Takayoshi; Yamada, Akiyo; Ozeki, Yoshihiro; Matsunaga, Etsuko; Ebinuma, Hiroyasu; Watanabe, Kazuo N

2013-01-01

Increasing soil salinization of arable land has a major impact on the global ecosystem. One approach to increase the usable global forest area is to develop transgenic trees with higher tolerance to conditions of salt stress. An allene oxide cyclase homolog, mangrin, contains a core protein domain that enhances the salt tolerance of its host. We utilized this feature to develop improved salt-tolerant eucalyptus trees, by using transgenic Eucalyptus camaldulensis carrying the mangrin gene as a model. Since the Japanese government requires an environmental biosafety assessment for the surrounding biosphere, we performed experiments on trees grown in a special netted-house. This study examined the transgenic E. camaldulensis carrying the mangrin gene to assess the feasibility of using these transformants, and assessed their salt tolerance and environmental biosafety. We found that seven of 36 transgenic genotypes had significantly higher salt tolerance than non-transformants, and more importantly, that these plants had no significant impact on environmental biosafety. These results suggest that introduction of the mangrin gene may be one approach to safely enhance salt tolerance in genetically modified Eucalyptus species, and that the transformants have no apparent risks in terms of environmental biosafety. Thus, this study provides valuable information regarding the use of transgenic trees in situ.

Aperture tolerances for neutron-imaging systems in inertial confinement fusion.

PubMed

Ghilea, M C; Sangster, T C; Meyerhofer, D D; Lerche, R A; Disdier, L

2008-02-01

Neutron-imaging systems are being considered as an ignition diagnostic for the National Ignition Facility (NIF) [Hogan et al., Nucl. Fusion 41, 567 (2001)]. Given the importance of these systems, a neutron-imaging design tool is being used to quantify the effects of aperture fabrication and alignment tolerances on reconstructed neutron images for inertial confinement fusion. The simulations indicate that alignment tolerances of more than 1 mrad would introduce measurable features in a reconstructed image for both pinholes and penumbral aperture systems. These simulations further show that penumbral apertures are several times less sensitive to fabrication errors than pinhole apertures.

Enhanced fault-tolerant quantum computing in d-level systems.

PubMed

Campbell, Earl T

2014-12-05

Error-correcting codes protect quantum information and form the basis of fault-tolerant quantum computing. Leading proposals for fault-tolerant quantum computation require codes with an exceedingly rare property, a transversal non-Clifford gate. Codes with the desired property are presented for d-level qudit systems with prime d. The codes use n=d-1 qudits and can detect up to ∼d/3 errors. We quantify the performance of these codes for one approach to quantum computation known as magic-state distillation. Unlike prior work, we find performance is always enhanced by increasing d.

The effect of fasting and body reserves on cold tolerance in 2 pit-building insect predators.

PubMed

Scharf, Inon; Daniel, Alma; MacMillan, Heath Andrew; Katz, Noa

2017-06-01

Pit-building antlions and wormlions are 2 distantly-related insect species, whose larvae construct pits in loose soil to trap small arthropod prey. This convergent evolution of natural histories has led to additional similarities in their natural history and ecology, and thus, these 2 species encounter similar abiotic stress (such as periodic starvation) in their natural habitat. Here, we measured the cold tolerance of the 2 species and examined whether recent feeding or food deprivation, as well as body composition (body mass and lipid content) and condition (quantified as mass-to-size residuals) affect their cold tolerance. In contrast to other insects, in which food deprivation either enhanced or impaired cold tolerance, prolonged fasting had no effect on the cold tolerance of either species, which had similar cold tolerance. The 2 species differed, however, in how cold tolerance related to body mass and lipid content: although body mass was positively correlated with the wormlion cold tolerance, lipid content was a more reliable predictor of cold tolerance in the antlions. Cold tolerance also underwent greater change with ontogeny in wormlions than in antlions. We discuss possible reasons for this lack of effect of food deprivation on both species' cold tolerance, such as their high starvation tolerance (being sit-and-wait predators).

Global analysis of glycoproteins identifies markers of endotoxin tolerant monocytes and GPR84 as a modulator of TNFα expression.

PubMed

Müller, Mario M; Lehmann, Roland; Klassert, Tilman E; Reifenstein, Stella; Conrad, Theresia; Moore, Christoph; Kuhn, Anna; Behnert, Andrea; Guthke, Reinhard; Driesch, Dominik; Slevogt, Hortense

2017-04-12

Exposure of human monocytes to lipopolysaccharide (LPS) induces a temporary insensitivity to subsequent LPS challenges, a cellular state called endotoxin tolerance. In this study, we investigated the LPS-induced global glycoprotein expression changes of tolerant human monocytes and THP-1 cells to identify markers and glycoprotein targets capable to modulate the immunosuppressive state. Using hydrazide chemistry and LC-MS/MS analysis, we analyzed glycoprotein expression changes during a 48 h LPS time course. The cellular snapshots at different time points identified 1491 glycoproteins expressed by monocytes and THP-1 cells. Label-free quantitative analysis revealed transient or long-lasting LPS-induced expression changes of secreted or membrane-anchored glycoproteins derived from intracellular membrane coated organelles or from the plasma membrane. Monocytes and THP-1 cells demonstrated marked differences in glycoproteins differentially expressed in the tolerant state. Among the shared differentially expressed glycoproteins G protein-coupled receptor 84 (GPR84) was identified as being capable of modulating pro-inflammatory TNFα mRNA expression in the tolerant cell state when activated with its ligand Decanoic acid.

Final Project Report. Scalable fault tolerance runtime technology for petascale computers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnamoorthy, Sriram; Sadayappan, P

With the massive number of components comprising the forthcoming petascale computer systems, hardware failures will be routinely encountered during execution of large-scale applications. Due to the multidisciplinary, multiresolution, and multiscale nature of scientific problems that drive the demand for high end systems, applications place increasingly differing demands on the system resources: disk, network, memory, and CPU. In addition to MPI, future applications are expected to use advanced programming models such as those developed under the DARPA HPCS program as well as existing global address space programming models such as Global Arrays, UPC, and Co-Array Fortran. While there has been amore » considerable amount of work in fault tolerant MPI with a number of strategies and extensions for fault tolerance proposed, virtually none of advanced models proposed for emerging petascale systems is currently fault aware. To achieve fault tolerance, development of underlying runtime and OS technologies able to scale to petascale level is needed. This project has evaluated range of runtime techniques for fault tolerance for advanced programming models.« less

Imperfect construction of microclusters

NASA Astrophysics Data System (ADS)

Schneider, E.; Zhou, K.; Gilbert, G.; Weinstein, Y. S.

2014-01-01

Microclusters are the basic building blocks used to construct cluster states capable of supporting fault-tolerant quantum computation. In this paper, we explore the consequences of errors on microcluster construction using two error models. To quantify the effect of the errors we calculate the fidelity of the constructed microclusters and the fidelity with which two such microclusters can be fused together. Such simulations are vital for gauging the capability of an experimental system to achieve fault tolerance.

Spatial variability in plant species composition and peatland carbon exchange

NASA Astrophysics Data System (ADS)

Goud, E.; Moore, T. R.; Roulet, N. T.

2015-12-01

Plant species shifts in response to global change will have significant impacts on ecosystem carbon (C) exchange and storage arising from changes in hydrology. Spatial variation in peatland C fluxes have largely been attributed to the spatial distribution of microhabitats that arise from variation in surface topography and water table depth, but little is known about how plant species composition impacts peatland C cycling or how these impacts will be influenced by changing environmental conditions. We quantified the effect of species composition and environmental variables on carbon dioxide (CO2) and methane (CH4) fluxes over 2 years in a temperate peatland for four plant communities situated along a water table gradient from ombrotrophic bog to beaver pond. We hypothesized that (i) spatial heterogeneity in species composition would drive predictable spatial heterogeneity in C fluxes due to variation in plant traits and ecological tolerances, and (ii) increases in peat temperature would increase C fluxes. Species had different effects on C fluxes primarily due to differences in leaf traits. Differences in ecological tolerances among communities resulted in different rates of CO2 exchange in response to changes in water table depth. There was an overall reduction in ecosystem respiration (ER), gross primary productivity (GPP) and CH4 flux in response to colder peat temperatures in the second year, and the additive effects of a deeper water table in the bog margin and pond sites further reduced flux rates in these areas. These results demonstrate that different plant species can increase or decrease the flux of C into and out of peatlands based on differences in leaf traits and ecological tolerances, and that CO2 and CH4 fluxes are sensitive to changes in soil temperature, especially when coupled with changes in moisture availability.

Near infrared and Raman spectroscopy as Process Analytical Technology tools for the manufacturing of silicone-based drug reservoirs.

PubMed

Mantanus, J; Rozet, E; Van Butsele, K; De Bleye, C; Ceccato, A; Evrard, B; Hubert, Ph; Ziémons, E

2011-08-05

Using near infrared (NIR) and Raman spectroscopy as PAT tools, 3 critical quality attributes of a silicone-based drug reservoir were studied. First, the Active Pharmaceutical Ingredient (API) homogeneity in the reservoir was evaluated using Raman spectroscopy (mapping): the API distribution within the industrial drug reservoirs was found to be homogeneous while API aggregates were detected in laboratory scale samples manufactured with a non optimal mixing process. Second, the crosslinking process of the reservoirs was monitored at different temperatures with NIR spectroscopy. Conformity tests and Principal Component Analysis (PCA) were performed on the collected data to find out the relation between the temperature and the time necessary to reach the crosslinking endpoints. An agreement was found between the conformity test results and the PCA results. Compared to the conformity test method, PCA had the advantage to discriminate the heating effect from the crosslinking effect occurring together during the monitored process. Therefore the 2 approaches were found to be complementary. Third, based on the HPLC reference method, a NIR model able to quantify the API in the drug reservoir was developed and thoroughly validated. Partial Least Squares (PLS) regression on the calibration set was performed to build prediction models of which the ability to quantify accurately was tested with the external validation set. The 1.2% Root Mean Squared Error of Prediction (RMSEP) of the NIR model indicated the global accuracy of the model. The accuracy profile based on tolerance intervals was used to generate a complete validation report. The 95% tolerance interval calculated on the validation results indicated that each future result will have a relative error below ±5% with a probability of at least 95%. In conclusion, 3 critical quality attributes of silicone-based drug reservoirs were quickly and efficiently evaluated by NIR and Raman spectroscopy. Copyright © 2011 Elsevier B.V. All rights reserved.

Modelling Movement Energetics Using Global Positioning System Devices in Contact Team Sports: Limitations and Solutions.

PubMed

Gray, Adrian J; Shorter, Kathleen; Cummins, Cloe; Murphy, Aron; Waldron, Mark

2018-06-01

Quantifying the training and competition loads of players in contact team sports can be performed in a variety of ways, including kinematic, perceptual, heart rate or biochemical monitoring methods. Whilst these approaches provide data relevant for team sports practitioners and athletes, their application to a contact team sport setting can sometimes be challenging or illogical. Furthermore, these methods can generate large fragmented datasets, do not provide a single global measure of training load and cannot adequately quantify all key elements of performance in contact team sports. A previous attempt to address these limitations via the estimation of metabolic energy demand (global energy measurement) has been criticised for its inability to fully quantify the energetic costs of team sports, particularly during collisions. This is despite the seemingly unintentional misapplication of the model's principles to settings outside of its intended use. There are other hindrances to the application of such models, which are discussed herein, such as the data-handling procedures of Global Position System manufacturers and the unrealistic expectations of end users. Nevertheless, we propose an alternative energetic approach, based on Global Positioning System-derived data, to improve the assessment of mechanical load in contact team sports. We present a framework for the estimation of mechanical work performed during locomotor and contact events with the capacity to globally quantify the work done during training and matches.

Model-based synthesis of locally contingent responses to global market signals

NASA Astrophysics Data System (ADS)

Magliocca, N. R.

2015-12-01

Rural livelihoods and the land systems on which they depend are increasingly influenced by distant markets through economic globalization. Place-based analyses of land and livelihood system sustainability must then consider both proximate and distant influences on local decision-making. Thus, advancing land change theory in the context of economic globalization calls for a systematic understanding of the general processes as well as local contingencies shaping local responses to global signals. Synthesis of insights from place-based case studies of land and livelihood change is a path forward for developing such systematic knowledge. This paper introduces a model-based synthesis approach to investigating the influence of local socio-environmental and agent-level factors in mediating land-use and livelihood responses to changing global market signals. A generalized agent-based modeling framework is applied to six case-study sites that differ in environmental conditions, market access and influence, and livelihood settings. The largest modeled land conversions and livelihood transitions to market-oriented production occurred in sties with relatively productive agricultural land and/or with limited livelihood options. Experimental shifts in the distributions of agents' risk tolerances generally acted to attenuate or amplify responses to changes in global market signals. Importantly, however, responses of agents at different points in the risk tolerance distribution varied widely, with the wealth gap growing wider between agents with higher or lower risk tolerance. These results demonstrate model-based synthesis is a promising approach to overcome many of the challenges of current synthesis methods in land change science, and to identify generalized as well as locally contingent responses to global market signals.

B Cell Receptor Signaling-Based Index as a Biomarker for the Loss of Peripheral Immune Tolerance in Autoreactive B Cells in Rheumatoid Arthritis

PubMed Central

Lyubchenko, Taras; Zerbe, Gary O.

2014-01-01

This study examines the loss of peripherally induced B cell immune tolerance in Rheumatoid arthritis (RA) and establishes a novel signaling-based measure of activation in a subset of autoreactive B cells - the Induced tolerance status index (ITSI). Naturally occurring naïve autoreactive B cells can escape the “classical” tolerogenic mechanisms of clonal deletion and receptor editing, but remain peripherally tolerized through B cell receptor (BCR) signaling inhibition (postdevelopmental “receptor tuning” or anergy). ITSI is a statistical index that numerically determines the level of homology between activation patterns of BCR signaling intermediaries in B cells that are either tolerized or activated by auto antigen exposure, and thus quantifies the level of peripheral immune tolerance. The index is based on the logistic regression analysis of phosphorylation levels in a panel of BCR signaling proteins. Our results demonstrate a new approach to identifying autoreactive B cells based on their BCR signaling features. PMID:25057856

Citizen science identifies the effects of nitrogen deposition, climate and tree species on epiphytic lichens across the UK.

PubMed

Welden, N A; Wolseley, P A; Ashmore, M R

2018-01-01

A national citizen survey quantified the abundance of epiphytic lichens that are known to be either sensitive or tolerant to nitrogen (N) deposition. Records were collected across the UK from over 10,000 individual trees of 22 deciduous species. Mean abundance of tolerant and sensitive lichens was related to mean N deposition rates and climatic variables at a 5 km scale, and the response of lichens was compared on the three most common trees (Quercus, Fraxinus and Acer) and by assigning all 22 tree species to three bark pH groups. The abundance of N-sensitive lichens on trunks decreased with increasing total N deposition, while that of N-tolerant lichens increased. The abundance of N-sensitive lichens on trunks was reduced close to a busy road, while the abundance of N-tolerant lichens increased. The abundance of N-tolerant lichen species on trunks was lower on Quercus and other low bark pH species, but the abundance of N-sensitive lichens was similar on different tree species. Lichen abundance relationships with total N deposition did not differ between tree species or bark pH groups. The response of N-sensitive lichens to reduced nitrogen was greater than to oxidised N, and the response of N-tolerant lichens was greater to oxidised N than to reduced N. There were differences in the response of N-sensitive and N-tolerant lichens to rainfall, humidity and temperature. Relationships with N deposition and climatic variables were similar for lichen presence on twigs as for lichen abundance on trunks, but N-sensitive lichens increased, rather than decreased, on twigs of Quercus/low bark pH species. The results demonstrate the unique power of citizen science to detect and quantify the air pollution impacts over a wide geographical range, and specifically to contribute to understanding of lichen responses to different chemical forms of N deposition, local pollution sources and bark chemistry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Plant tolerance to high temperature in a changing environment: scientific fundamentals and production of heat stress-tolerant crops

PubMed Central

Bita, Craita E.; Gerats, Tom

2013-01-01

Global warming is predicted to have a general negative effect on plant growth due to the damaging effect of high temperatures on plant development. The increasing threat of climatological extremes including very high temperatures might lead to catastrophic loss of crop productivity and result in wide spread famine. In this review, we assess the impact of global climate change on the agricultural crop production. There is a differential effect of climate change both in terms of geographic location and the crops that will likely show the most extreme reductions in yield as a result of expected extreme fluctuations in temperature and global warming in general. High temperature stress has a wide range of effects on plants in terms of physiology, biochemistry and gene regulation pathways. However, strategies exist to crop improvement for heat stress tolerance. In this review, we present recent advances of research on all these levels of investigation and focus on potential leads that may help to understand more fully the mechanisms that make plants tolerant or susceptible to heat stress. Finally, we review possible procedures and methods which could lead to the generation of new varieties with sustainable yield production, in a world likely to be challenged both by increasing population, higher average temperatures and larger temperature fluctuations. PMID:23914193

Plant tolerance to high temperature in a changing environment: scientific fundamentals and production of heat stress-tolerant crops.

PubMed

Bita, Craita E; Gerats, Tom

2013-01-01

Global warming is predicted to have a general negative effect on plant growth due to the damaging effect of high temperatures on plant development. The increasing threat of climatological extremes including very high temperatures might lead to catastrophic loss of crop productivity and result in wide spread famine. In this review, we assess the impact of global climate change on the agricultural crop production. There is a differential effect of climate change both in terms of geographic location and the crops that will likely show the most extreme reductions in yield as a result of expected extreme fluctuations in temperature and global warming in general. High temperature stress has a wide range of effects on plants in terms of physiology, biochemistry and gene regulation pathways. However, strategies exist to crop improvement for heat stress tolerance. In this review, we present recent advances of research on all these levels of investigation and focus on potential leads that may help to understand more fully the mechanisms that make plants tolerant or susceptible to heat stress. Finally, we review possible procedures and methods which could lead to the generation of new varieties with sustainable yield production, in a world likely to be challenged both by increasing population, higher average temperatures and larger temperature fluctuations.

Expanding Horizons through Global Learning in Out-of-School Time

ERIC Educational Resources Information Center

Menten, Alexis

2011-01-01

The demands and opportunities of globalization involve not only America's economic competitiveness, but also national security, the need for tolerance in increasingly diverse communities, and a need to solve pressing social issues. To be successful, students need a comprehensive and integrated set of global learning experiences that help them…

Tolerance of Snakes to Hypergravity

NASA Technical Reports Server (NTRS)

Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.

1994-01-01

Sensitivity of carotid blood flow to +Gz (head-to-tail) acceleration was studied in six species of snakes hypothesized to show varied adaptive cardiovascular responses to gravity. Blood flow in the proximal carotid artery was measured in 15 snakes before, during and following stepwise increments of +0.25Gz force produced on a 2.4 m diameter centrifuge. During centrifugation each snake was confined to a straight position within an individually- fitted acrylic tube with the head facing the center of rotation. We measured the centrifugal force at the tail of the snake in order to quantify the maximum intensity of force gradient promoting antero-posterior pooling of blood. Tolerance to increased gravity was quantified as the acceleration force at which carotid blood flow ceased. This parameter varied according to the gravitational adaptation of species defined by their ecology and behavior. At the extremes, carotid blood flow decreased in response to increasing gravity and approached zero near +1Gz in aquatic and ground-dwelling species, whereas in climbing species carotid flow was maintained at forces in excess of +2Gz. Surprisingly, tolerant (arboreal) species withstood hypergravic forces of +2 to +3 G. for periods up to 1 h without cessation of carotid blood flow or apparent loss of consciousness. Data suggest that relatively tight skin of the tolerant species provides a natural antigravity suit which is of prime importance in counteracting Gz stress on blood circulation.

Quantifying tolerance indicator values for common stream fish species of the United States

USGS Publications Warehouse

Meador, M.R.; Carlisle, D.M.

2007-01-01

The classification of fish species tolerance to environmental disturbance is often used as a means to assess ecosystem conditions. Its use, however, may be problematic because the approach to tolerance classification is based on subjective judgment. We analyzed fish and physicochemical data from 773 stream sites collected as part of the U.S. Geological Survey's National Water-Quality Assessment Program to calculate tolerance indicator values for 10 physicochemical variables using weighted averaging. Tolerance indicator values (TIVs) for ammonia, chloride, dissolved oxygen, nitrite plus nitrate, pH, phosphorus, specific conductance, sulfate, suspended sediment, and water temperature were calculated for 105 common fish species of the United States. Tolerance indicator values for specific conductance and sulfate were correlated (rho = 0.87), and thus, fish species may be co-tolerant to these water-quality variables. We integrated TIVs for each species into an overall tolerance classification for comparisons with judgment-based tolerance classifications. Principal components analysis indicated that the distinction between tolerant and intolerant classifications was determined largely by tolerance to suspended sediment, specific conductance, chloride, and total phosphorus. Factors such as water temperature, dissolved oxygen, and pH may not be as important in distinguishing between tolerant and intolerant classifications, but may help to segregate species classified as moderate. Empirically derived tolerance classifications were 58.8% in agreement with judgment-derived tolerance classifications. Canonical discriminant analysis revealed that few TIVs, primarily chloride, could discriminate among judgment-derived tolerance classifications of tolerant, moderate, and intolerant. To our knowledge, this is the first empirically based understanding of fish species tolerance for stream fishes in the United States.

Probabilistic Assessment of Fracture Progression in Composite Structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Minnetyan, Levon; Mauget, Bertrand; Huang, Dade; Addi, Frank

1999-01-01

This report describes methods and corresponding computer codes that are used to evaluate progressive damage and fracture and to perform probabilistic assessment in built-up composite structures. Structural response is assessed probabilistically, during progressive fracture. The effects of design variable uncertainties on structural fracture progression are quantified. The fast probability integrator (FPI) is used to assess the response scatter in the composite structure at damage initiation. The sensitivity of the damage response to design variables is computed. The methods are general purpose and are applicable to stitched and unstitched composites in all types of structures and fracture processes starting from damage initiation to unstable propagation and to global structure collapse. The methods are demonstrated for a polymer matrix composite stiffened panel subjected to pressure. The results indicated that composite constituent properties, fabrication parameters, and respective uncertainties have a significant effect on structural durability and reliability. Design implications with regard to damage progression, damage tolerance, and reliability of composite structures are examined.

Phytosanitary irradiation and fresh fruit quality: Cultivar and maturity effects

USDA-ARS?s Scientific Manuscript database

Irradiation is an effective quarantine treatment for global trade of fresh produce. Variation in cultivars and maturity stages can impact the tolerance of fresh fruits to irradiation for the purposes of quarantine security. Tolerance thresholds for irradiated fruit are lacking for a large number of ...

Genome‐wide identification of tolerance mechanisms toward p‐coumaric acid in Pseudomonas putida

PubMed Central

Calero, Patricia; Jensen, Sheila I.; Bojanovič, Klara; Lennen, Rebecca M.; Koza, Anna

2017-01-01

Abstract The soil bacterium Pseudomonas putida KT2440 has gained increasing biotechnological interest due to its ability to tolerate different types of stress. Here, the tolerance of P. putida KT2440 toward eleven toxic chemical compounds was investigated. P. putida was found to be significantly more tolerant toward three of the eleven compounds when compared to Escherichia coli. Increased tolerance was for example found toward p‐coumaric acid, an interesting precursor for polymerization with a significant industrial relevance. The tolerance mechanism was therefore investigated using the genome‐wide approach, Tn‐seq. Libraries containing a large number of miniTn5‐Km transposon insertion mutants were grown in the presence and absence of p‐coumaric acid, and the enrichment or depletion of mutants was quantified by high‐throughput sequencing. Several genes, including the ABC transporter Ttg2ABC and the cytochrome c maturation system (ccm), were identified to play an important role in the tolerance toward p‐coumaric acid of this bacterium. Most of the identified genes were involved in membrane stability, suggesting that tolerance toward p‐coumaric acid is related to transport and membrane integrity. PMID:29131301

Quantification of Carbohydrates in Grape Tissues Using Capillary Zone Electrophoresis

PubMed Central

Zhao, Lu; Chanon, Ann M.; Chattopadhyay, Nabanita; Dami, Imed E.; Blakeslee, Joshua J.

2016-01-01

Soluble sugars play an important role in freezing tolerance in both herbaceous and woody plants, functioning in both the reduction of freezing-induced dehydration and the cryoprotection of cellular constituents. The quantification of soluble sugars in plant tissues is, therefore, essential in understanding freezing tolerance. While a number of analytical techniques and methods have been used to quantify sugars, most of these are expensive and time-consuming due to complex sample preparation procedures which require the derivatization of the carbohydrates being analyzed. Analysis of soluble sugars using capillary zone electrophoresis (CZE) under alkaline conditions with direct UV detection has previously been used to quantify simple sugars in fruit juices. However, it was unclear whether CZE-based methods could be successfully used to quantify the broader range of sugars present in complex plant extracts. Here, we present the development of an optimized CZE method capable of separating and quantifying mono-, di-, and tri-saccharides isolated from plant tissues. This optimized CZE method employs a column electrolyte buffer containing 130 mM NaOH, pH 13.0, creating a current of 185 μA when a separation voltage of 10 kV is employed. The optimized CZE method provides limits-of-detection (an average of 1.5 ng/μL) for individual carbohydrates comparable or superior to those obtained using gas chromatography–mass spectrometry, and allows resolution of non-structural sugars and cell wall components (structural sugars). The optimized CZE method was successfully used to quantify sugars from grape leaves and buds, and is a robust tool for the quantification of plant sugars found in vegetative and woody tissues. The increased analytical efficiency of this CZE method makes it ideal for use in high-throughput metabolomics studies designed to quantify plant sugars. PMID:27379118

Local and global evaluation for remote sensing image segmentation

NASA Astrophysics Data System (ADS)

Su, Tengfei; Zhang, Shengwei

2017-08-01

In object-based image analysis, how to produce accurate segmentation is usually a very important issue that needs to be solved before image classification or target recognition. The study for segmentation evaluation method is key to solving this issue. Almost all of the existent evaluation strategies only focus on the global performance assessment. However, these methods are ineffective for the situation that two segmentation results with very similar overall performance have very different local error distributions. To overcome this problem, this paper presents an approach that can both locally and globally quantify segmentation incorrectness. In doing so, region-overlapping metrics are utilized to quantify each reference geo-object's over and under-segmentation error. These quantified error values are used to produce segmentation error maps which have effective illustrative power to delineate local segmentation error patterns. The error values for all of the reference geo-objects are aggregated through using area-weighted summation, so that global indicators can be derived. An experiment using two scenes of very different high resolution images showed that the global evaluation part of the proposed approach was almost as effective as other two global evaluation methods, and the local part was a useful complement to comparing different segmentation results.

Global Metabolic Responses to Salt Stress in Fifteen Species

PubMed Central

Pollak, Georg R.; Kuehne, Andreas; Sauer, Uwe

2016-01-01

Cells constantly adapt to unpredictably changing extracellular solute concentrations. A cornerstone of the cellular osmotic stress response is the metabolic supply of energy and building blocks to mount appropriate defenses. Yet, the extent to which osmotic stress impinges on the metabolic network remains largely unknown. Moreover, it is mostly unclear which, if any, of the metabolic responses to osmotic stress are conserved among diverse organisms or confined to particular groups of species. Here we investigate the global metabolic responses of twelve bacteria, two yeasts and two human cell lines exposed to sustained hyperosmotic salt stress by measuring semiquantitative levels of hundreds of cellular metabolites using nontargeted metabolomics. Beyond the accumulation of osmoprotectants, we observed significant changes of numerous metabolites in all species. Global metabolic responses were predominantly species-specific, yet individual metabolites were characteristically affected depending on species’ taxonomy, natural habitat, envelope structure or salt tolerance. Exploiting the breadth of our dataset, the correlation of individual metabolite response magnitudes across all species implicated lower glycolysis, tricarboxylic acid cycle, branched-chain amino acid metabolism and heme biosynthesis to be generally important for salt tolerance. Thus, our findings place the global metabolic salt stress response into a phylogenetic context and provide insights into the cellular phenotype associated with salt tolerance. PMID:26848578

Suitable Environmental Ranges for Potential Coral Reef Habitats in the Tropical Ocean

PubMed Central

Guan, Yi; Hohn, Sönke; Merico, Agostino

2015-01-01

Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7—29.6 °C for temperature, 28.7—40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed. PMID:26030287

Suitable environmental ranges for potential coral reef habitats in the tropical ocean.

PubMed

Guan, Yi; Hohn, Sönke; Merico, Agostino

2015-01-01

Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7-29.6 °C for temperature, 28.7-40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed.

Climate tolerances and trait choices shape continental patterns of urban tree biodiversity

Treesearch

G. Darrel Jenerette; Lorraine W. Clarke; Meghan L. Avolio; Diane E. Pataki; Thomas W. Gillespie; Stephanie Pincetl; Dave J. Nowak; Lucy R. Hutyra; Melissa McHale; Joseph P. McFadden; Michael Alonzo

2016-01-01

Aim. We propose and test a climate tolerance and trait choice hypothesis of urban macroecological variation in which strong filtering associated with low winter temperatures restricts urban biodiversity while weak filtering associated with warmer temperatures and irrigation allows dispersal of species from a global source pool, thereby...

The evolution of environmental tolerance and range size: a comparison of geographically restricted and widespread Mimulus.

PubMed

Sheth, Seema N; Angert, Amy L

2014-10-01

The geographic ranges of closely related species can vary dramatically, yet we do not fully grasp the mechanisms underlying such variation. The niche breadth hypothesis posits that species that have evolved broad environmental tolerances can achieve larger geographic ranges than species with narrow environmental tolerances. In turn, plasticity and genetic variation in ecologically important traits and adaptation to environmentally variable areas can facilitate the evolution of broad environmental tolerance. We used five pairs of western North American monkeyflowers to experimentally test these ideas by quantifying performance across eight temperature regimes. In four species pairs, species with broader thermal tolerances had larger geographic ranges, supporting the niche breadth hypothesis. As predicted, species with broader thermal tolerances also had more within-population genetic variation in thermal reaction norms and experienced greater thermal variation across their geographic ranges than species with narrow thermal tolerances. Species with narrow thermal tolerance may be particularly vulnerable to changing climatic conditions due to lack of plasticity and insufficient genetic variation to respond to novel selection pressures. Conversely, species experiencing high variation in temperature across their ranges may be buffered against extinction due to climatic changes because they have evolved tolerance to a broad range of temperatures. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Salinity effects on behavioural response to hypoxia in the non-native Mayan cichlid Cichlasoma urophthalmus from Florida Everglades wetlands.

PubMed

Schofield, P J; Loftus, W F; Fontaine, J A

2009-04-01

This study quantified the hypoxia tolerance of the Mayan cichlid Cichlasoma urophthalmus over a range of salinities. The species was very tolerant of hypoxia, using aquatic surface respiration (ASR) and buccal bubble holding when oxygen tensions dropped to <20 mmHg (c. 1.0 mg l(-1)) and 6 mmHg, respectively. Salinity had little effect on the hypoxia tolerance of C. urophthalmus, except that bubble holding was more frequent at the higher salinities tested. Levels of aggression were greatest at the highest salinity. The ASR thresholds of C. urophthalmus were similar to native centrarchid sunfishes from the Everglades, however, aggression levels for C. uropthalmus were markedly higher.

Handbook of human engineering design data for reduced gravity conditions

NASA Technical Reports Server (NTRS)

Marton, T.; Rudek, F. P.; Miller, R. A.; Norman, D. G.

1971-01-01

A Handbook is presented for the use of engineers, designers, and human factors specialists during the developmental and detailed design phases of manned spacecraft programs. Detailed and diverse quantified data on man's capabilities and tolerances for survival and productive effort in the extraterrestrial environment are provided. Quantified data and information on the space environment as well as the characteristics of the vehicular or residential environment required to support man in outer space are also given.

Toleration and the Design of Norms.

PubMed

Floridi, Luciano

2015-10-01

One of the pressing challenges we face today-in a post-Westphalian order (emergence of the state as the modern, political information agent) and post-Bretton Woods world (emergence of non-state multiagent systems or MASs as "hyperhistorical" players in the global economy and politics)-is how to design the right kind of MAS that can take full advantage of the socio-economic and political progress made so far, while dealing successfully with the new global challenges that are undermining the best legacy of that very progress. This is the topic of the article. In it, I argue that (i) in order to design the right kind of MAS, we need to design the right kind of norms that constitute them; (ii) in order to design the right kind of constitutive norms, we need to identify and adopt the right kind of principles of normative design; (iii) toleration is one of those principles; (iv) unfortunately, its role as a foundation for the design of norms has been undermined by the "paradox of toleration"; (v) however, the paradox can be solved; (vi) so toleration can be re-instated as the right kind of foundational principle for the design of the right kind of norms that can constitute the right kind of MAS that can operate across cultures, societies and states, to help us to tackle the new global challenges facing us.

Coevolutionary network approach to cultural dynamics controlled by intolerance

NASA Astrophysics Data System (ADS)

Gracia-Lázaro, Carlos; Quijandría, Fernando; Hernández, Laura; Floría, Luis Mario; Moreno, Yamir

2011-12-01

Starting from Axelrod's model of cultural dissemination, we introduce a rewiring probability, enabling agents to cut the links with their unfriendly neighbors if their cultural similarity is below a tolerance parameter. For low values of tolerance, rewiring promotes the convergence to a frozen monocultural state. However, intermediate tolerance values prevent rewiring once the network is fragmented, resulting in a multicultural society even for values of initial cultural diversity in which the original Axelrod model reaches globalization.

Parameter-tolerant design of high contrast gratings

NASA Astrophysics Data System (ADS)

Chevallier, Christyves; Fressengeas, Nicolas; Jacquet, Joel; Almuneau, Guilhem; Laaroussi, Youness; Gauthier-Lafaye, Olivier; Cerutti, Laurent; Genty, Frédéric

2015-02-01

This work is devoted to the design of high contrast grating mirrors taking into account the technological constraints and tolerance of fabrication. First, a global optimization algorithm has been combined to a numerical analysis of grating structures (RCWA) to automatically design HCG mirrors. Then, the tolerances of the grating dimensions have been precisely studied to develop a robust optimization algorithm with which high contrast gratings, exhibiting not only a high efficiency but also large tolerance values, could be designed. Finally, several structures integrating previously designed HCGs has been simulated to validate and illustrate the interest of such gratings.

Avian thermoregulation in the heat: evaporative cooling in five Australian passerines reveals within-order biogeographic variation in heat tolerance.

PubMed

McKechnie, Andrew E; Gerson, Alexander R; McWhorter, Todd J; Smith, Eric Krabbe; Talbot, William A; Wolf, Blair O

2017-07-01

Evaporative heat loss pathways vary among avian orders, but the extent to which evaporative cooling capacity and heat tolerance vary within orders remains unclear. We quantified the upper limits to thermoregulation under extremely hot conditions in five Australian passerines: yellow-plumed honeyeater ( Lichenostomus ornatus ; ∼17 g), spiny-cheeked honeyeater ( Acanthagenys rufogularis ; ∼42 g), chestnut-crowned babbler ( Pomatostomus ruficeps ; ∼52 g), grey butcherbird ( Cracticus torquatus ; ∼86 g) and apostlebird ( Struthidea cinerea ; ∼118 g). At air temperatures ( T a ) exceeding body temperature ( T b ), all five species showed increases in T b to maximum values around 44-45°C, accompanied by rapid increases in resting metabolic rate above clearly defined upper critical limits of thermoneutrality and increases in evaporative water loss (EWL) to levels equivalent to 670-860% of baseline rates at thermoneutral T a Maximum cooling capacity, quantified as the fraction of metabolic heat production dissipated evaporatively, ranged from 1.20 to 2.17, consistent with the known range for passerines, and well below the corresponding ranges for columbids and caprimulgids. Heat tolerance limit (HTL, the maximum T a tolerated) scaled positively with body mass, varying from 46°C in yellow-plumed honeyeaters to 52°C in a single apostlebird, but was lower than that of three southern African ploceid passerines investigated previously. We argue this difference is functionally linked to a smaller scope for increases in EWL above baseline levels. Our data reiterate the reliance of passerines in general on respiratory evaporative heat loss via panting, but also reveal substantial within-order variation in heat tolerance and evaporative cooling capacity. © 2017. Published by The Company of Biologists Ltd.

Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics

NASA Astrophysics Data System (ADS)

Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

2015-12-01

Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.

Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics.

PubMed

Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

2015-12-22

Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.

Water, bound and mobile

EPA Science Inventory

Resolving the global transpiration flux is critical to constraining global carbon cycle models because carbon uptake by photosynthesis in terrestrial plants (Gross Primary Productivity, GPP) is directly related to water lost through transpiration. Quantifying GPP globally is cha...

Shifts in tree functional composition amplify the response of forest biomass to climate

NASA Astrophysics Data System (ADS)

Zhang, Tao; Niinemets, Ülo; Sheffield, Justin; Lichstein, Jeremy W.

2018-04-01

Forests have a key role in global ecosystems, hosting much of the world’s terrestrial biodiversity and acting as a net sink for atmospheric carbon. These and other ecosystem services that are provided by forests may be sensitive to climate change as well as climate variability on shorter time scales (for example, annual to decadal). Previous studies have documented responses of forest ecosystems to climate change and climate variability, including drought-induced increases in tree mortality rates. However, relationships between forest biomass, tree species composition and climate variability have not been quantified across a large region using systematically sampled data. Here we use systematic forest inventories from the 1980s and 2000s across the eastern USA to show that forest biomass responds to decadal-scale changes in water deficit, and that this biomass response is amplified by concurrent changes in community-mean drought tolerance, a functionally important aspect of tree species composition. The amplification of the direct effects of water stress on biomass occurs because water stress tends to induce a shift in tree species composition towards species that are more tolerant to drought but are slower growing. These results demonstrate concurrent changes in forest species composition and biomass carbon storage across a large, systematically sampled region, and highlight the potential for climate-induced changes in forest ecosystems across the world, resulting from both direct effects of climate on forest biomass and indirect effects mediated by shifts in species composition.

Shifts in tree functional composition amplify the response of forest biomass to climate.

PubMed

Zhang, Tao; Niinemets, Ülo; Sheffield, Justin; Lichstein, Jeremy W

2018-04-05

Forests have a key role in global ecosystems, hosting much of the world's terrestrial biodiversity and acting as a net sink for atmospheric carbon. These and other ecosystem services that are provided by forests may be sensitive to climate change as well as climate variability on shorter time scales (for example, annual to decadal). Previous studies have documented responses of forest ecosystems to climate change and climate variability, including drought-induced increases in tree mortality rates. However, relationships between forest biomass, tree species composition and climate variability have not been quantified across a large region using systematically sampled data. Here we use systematic forest inventories from the 1980s and 2000s across the eastern USA to show that forest biomass responds to decadal-scale changes in water deficit, and that this biomass response is amplified by concurrent changes in community-mean drought tolerance, a functionally important aspect of tree species composition. The amplification of the direct effects of water stress on biomass occurs because water stress tends to induce a shift in tree species composition towards species that are more tolerant to drought but are slower growing. These results demonstrate concurrent changes in forest species composition and biomass carbon storage across a large, systematically sampled region, and highlight the potential for climate-induced changes in forest ecosystems across the world, resulting from both direct effects of climate on forest biomass and indirect effects mediated by shifts in species composition.

How can we improve crop genotypes to increase stress resilience and productivity in a future climate? A new crop screening method based on productivity and resistance to abiotic stress

PubMed Central

Thiry, Arnauld A.; Chavez Dulanto, Perla N.; Reynolds, Matthew P.; Davies, William J.

2016-01-01

The need to accelerate the selection of crop genotypes that are both resistant to and productive under abiotic stress is enhanced by global warming and the increase in demand for food by a growing world population. In this paper, we propose a new method for evaluation of wheat genotypes in terms of their resilience to stress and their production capacity. The method quantifies the components of a new index related to yield under abiotic stress based on previously developed stress indices, namely the stress susceptibility index, the stress tolerance index, the mean production index, the geometric mean production index, and the tolerance index, which were created originally to evaluate drought adaptation. The method, based on a scoring scale, offers simple and easy visualization and identification of resilient, productive and/or contrasting genotypes according to grain yield. This new selection method could help breeders and researchers by defining clear and strong criteria to identify genotypes with high resilience and high productivity and provide a clear visualization of contrasts in terms of grain yield production under stress. It is also expected that this methodology will reduce the time required for first selection and the number of first-selected genotypes for further evaluation by breeders and provide a basis for appropriate comparisons of genotypes that would help reveal the biology behind high stress productivity of crops. PMID:27677299

Probabilistic structural analysis to quantify uncertainties associated with turbopump blades

NASA Technical Reports Server (NTRS)

Nagpal, Vinod K.; Rubinstein, Robert; Chamis, Christos C.

1988-01-01

A probabilistic study of turbopump blades has been in progress at NASA Lewis Research Center for over the last two years. The objectives of this study are to evaluate the effects of uncertainties in geometry and material properties on the structural response of the turbopump blades to evaluate the tolerance limits on the design. A methodology based on probabilistic approach was developed to quantify the effects of the random uncertainties. The results indicate that only the variations in geometry have significant effects.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katti, Amogh; Di Fatta, Giuseppe; Naughton III, Thomas J

Future extreme-scale high-performance computing systems will be required to work under frequent component failures. The MPI Forum's User Level Failure Mitigation proposal has introduced an operation, MPI_Comm_shrink, to synchronize the alive processes on the list of failed processes, so that applications can continue to execute even in the presence of failures by adopting algorithm-based fault tolerance techniques. This MPI_Comm_shrink operation requires a fault tolerant failure detection and consensus algorithm. This paper presents and compares two novel failure detection and consensus algorithms. The proposed algorithms are based on Gossip protocols and are inherently fault-tolerant and scalable. The proposed algorithms were implementedmore » and tested using the Extreme-scale Simulator. The results show that in both algorithms the number of Gossip cycles to achieve global consensus scales logarithmically with system size. The second algorithm also shows better scalability in terms of memory and network bandwidth usage and a perfect synchronization in achieving global consensus.« less

Adaptation to hot climate and strategies to alleviate heat stress in livestock production.

PubMed

Renaudeau, D; Collin, A; Yahav, S; de Basilio, V; Gourdine, J L; Collier, R J

2012-05-01

Despite many challenges faced by animal producers, including environmental problems, diseases, economic pressure, and feed availability, it is still predicted that animal production in developing countries will continue to sustain the future growth of the world's meat production. In these areas, livestock performance is generally lower than those obtained in Western Europe and North America. Although many factors can be involved, climatic factors are among the first and crucial limiting factors of the development of animal production in warm regions. In addition, global warming will further accentuate heat stress-related problems. The objective of this paper was to review the effective strategies to alleviate heat stress in the context of tropical livestock production systems. These strategies can be classified into three groups: those increasing feed intake or decreasing metabolic heat production, those enhancing heat-loss capacities, and those involving genetic selection for heat tolerance. Under heat stress, improved production should be possible through modifications of diet composition that either promotes a higher intake or compensates the low feed consumption. In addition, altering feeding management such as a change in feeding time and/or frequency, are efficient tools to avoid excessive heat load and improve survival rate, especially in poultry. Methods to enhance heat exchange between the environment and the animal and those changing the environment to prevent or limit heat stress can be used to improve performance under hot climatic conditions. Although differences in thermal tolerance exist between livestock species (ruminants > monogastrics), there are also large differences between breeds of a species and within each breed. Consequently, the opportunity may exist to improve thermal tolerance of the animals using genetic tools. However, further research is required to quantify the genetic antagonism between adaptation and production traits to evaluate the potential selection response. With the development of molecular biotechnologies, new opportunities are available to characterize gene expression and identify key cellular responses to heat stress. These new tools will enable scientists to improve the accuracy and the efficiency of selection for heat tolerance. Epigenetic regulation of gene expression and thermal imprinting of the genome could also be an efficient method to improve thermal tolerance. Such techniques (e.g. perinatal heat acclimation) are currently being experimented in chicken.

UNITED STATES DEPARTMENT OF TRANSPORTATION GLOBAL POSITIONING SYSTEM (GPS) ADJACENT BAND COMPATIBILITY ASSESSMENT

DOT National Transportation Integrated Search

2018-04-01

The goal of the U.S. Department of Transportation (DOT) Global Positioning System (GPS) Adjacent Band Compatibility Assessment is to evaluate the maximum transmitted power levels of adjacent band radiofrequency (RF) systems that can be tolerated by G...

The carbon footprint of global tourism

NASA Astrophysics Data System (ADS)

Lenzen, Manfred; Sun, Ya-Yen; Faturay, Futu; Ting, Yuan-Peng; Geschke, Arne; Malik, Arunima

2018-06-01

Tourism contributes significantly to global gross domestic product, and is forecast to grow at an annual 4%, thus outpacing many other economic sectors. However, global carbon emissions related to tourism are currently not well quantified. Here, we quantify tourism-related global carbon flows between 160 countries, and their carbon footprints under origin and destination accounting perspectives. We find that, between 2009 and 2013, tourism's global carbon footprint has increased from 3.9 to 4.5 GtCO2e, four times more than previously estimated, accounting for about 8% of global greenhouse gas emissions. Transport, shopping and food are significant contributors. The majority of this footprint is exerted by and in high-income countries. The rapid increase in tourism demand is effectively outstripping the decarbonization of tourism-related technology. We project that, due to its high carbon intensity and continuing growth, tourism will constitute a growing part of the world's greenhouse gas emissions.

Thermal tolerance and climate warming sensitivity in tropical snails.

PubMed

Marshall, David J; Rezende, Enrico L; Baharuddin, Nursalwa; Choi, Francis; Helmuth, Brian

2015-12-01

Tropical ectotherms are predicted to be especially vulnerable to climate change because their thermal tolerance limits generally lie close to current maximum air temperatures. This prediction derives primarily from studies on insects and lizards and remains untested for other taxa with contrasting ecologies. We studied the HCT (heat coma temperatures) and ULT (upper lethal temperatures) of 40 species of tropical eulittoral snails (Littorinidae and Neritidae) inhabiting exposed rocky shores and shaded mangrove forests in Oceania, Africa, Asia and North America. We also estimated extremes in animal body temperature at each site using a simple heat budget model and historical (20 years) air temperature and solar radiation data. Phylogenetic analyses suggest that HCT and ULT exhibit limited adaptive variation across habitats (mangroves vs. rocky shores) or geographic locations despite their contrasting thermal regimes. Instead, the elevated heat tolerance of these species (HCT = 44.5 ± 1.8°C and ULT = 52.1 ± 2.2°C) seems to reflect the extreme temperature variability of intertidal systems. Sensitivity to climate warming, which was quantified as the difference between HCT or ULT and maximum body temperature, differed greatly between snails from sunny (rocky shore; Thermal Safety Margin, TSM = -14.8 ± 3.3°C and -6.2 ± 4.4°C for HCT and ULT, respectively) and shaded (mangrove) habitats (TSM = 5.1 ± 3.6°C and 12.5 ± 3.6°C). Negative TSMs in rocky shore animals suggest that mortality is likely ameliorated during extreme climatic events by behavioral thermoregulation. Given the low variability in heat tolerance across species, habitat and geographic location account for most of the variation in TSM and may adequately predict the vulnerability to climate change. These findings caution against generalizations on the impact of global warming across ectothermic taxa and highlight how the consideration of nonmodel animals, ecological transitions, and behavioral responses may alter predictions of studies that ignore these biological details.

Disentangling Human Tolerance and Resistance Against HIV

PubMed Central

Regoes, Roland R.; McLaren, Paul J.; Battegay, Manuel; Bernasconi, Enos; Calmy, Alexandra; Günthard, Huldrych F.; Hoffmann, Matthias; Rauch, Andri; Telenti, Amalio; Fellay, Jacques

2014-01-01

In ecology, “disease tolerance” is defined as an evolutionary strategy of hosts against pathogens, characterized by reduced or absent pathogenesis despite high pathogen load. To our knowledge, tolerance has to date not been quantified and disentangled from host resistance to disease in any clinically relevant human infection. Using data from the Swiss HIV Cohort Study, we investigated if there is variation in tolerance to HIV in humans and if this variation is associated with polymorphisms in the human genome. In particular, we tested for associations between tolerance and alleles of the Human Leukocyte Antigen (HLA) genes, the CC chemokine receptor 5 (CCR5), the age at which individuals were infected, and their sex. We found that HLA-B alleles associated with better HIV control do not confer tolerance. The slower disease progression associated with these alleles can be fully attributed to the extent of viral load reduction in carriers. However, we observed that tolerance significantly varies across HLA-B genotypes with a relative standard deviation of 34%. Furthermore, we found that HLA-B homozygotes are less tolerant than heterozygotes. Lastly, tolerance was observed to decrease with age, resulting in a 1.7-fold difference in disease progression between 20 and 60-y-old individuals with the same viral load. Thus, disease tolerance is a feature of infection with HIV, and the identification of the mechanisms involved may pave the way to a better understanding of pathogenesis. PMID:25226169

Salinity effects on behavioural response to hypoxia in the non-native Mayan cichlid Cichlasoma urophthalmus from Florida Everglades wetlands

USGS Publications Warehouse

Schofield, P.J.; Loftus, W.F.; Fontaine, J.A.

2009-01-01

This study quantified the hypoxia tolerance of the Mayan cichlid Cichlasoma urophthalmus over a range of salinities. The species was very tolerant of hypoxia, using aquatic surface respiration (ASR) and buccal bubble holding when oxygen tensions dropped to <20 mmHg (c. 1??0 mg l-1) and 6 mmHg, respectively. Salinity had little effect on the hypoxia tolerance of C. urophthalmus, except that bubble holding was more frequent at the higher salinities tested. Levels of aggression were greatest at the highest salinity. The ASR thresholds of C. urophthalmus were similar to native centrarchid sunfishes from the Everglades, however, aggression levels for C. uropthalmus were markedly higher. ?? 2009 The Fisheries Society of the British Isles.

Probabilistic Evaluation of Blade Impact Damage

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Abumeri, G. H.

2003-01-01

The response to high velocity impact of a composite blade is probabilistically evaluated. The evaluation is focused on quantifying probabilistically the effects of uncertainties (scatter) in the variables that describe the impact, the blade make-up (geometry and material), the blade response (displacements, strains, stresses, frequencies), the blade residual strength after impact, and the blade damage tolerance. The results of probabilistic evaluations results are in terms of probability cumulative distribution functions and probabilistic sensitivities. Results show that the blade has relatively low damage tolerance at 0.999 probability of structural failure and substantial at 0.01 probability.

CORAL REEFS. Genomic determinants of coral heat tolerance across latitudes.

PubMed

Dixon, Groves B; Davies, Sarah W; Aglyamova, Galina A; Meyer, Eli; Bay, Line K; Matz, Mikhail V

2015-06-26

As global warming continues, reef-building corals could avoid local population declines through "genetic rescue" involving exchange of heat-tolerant genotypes across latitudes, but only if latitudinal variation in thermal tolerance is heritable. Here, we show an up-to-10-fold increase in odds of survival of coral larvae under heat stress when their parents come from a warmer lower-latitude location. Elevated thermal tolerance was associated with heritable differences in expression of oxidative, extracellular, transport, and mitochondrial functions that indicated a lack of prior stress. Moreover, two genomic regions strongly responded to selection for thermal tolerance in interlatitudinal crosses. These results demonstrate that variation in coral thermal tolerance across latitudes has a strong genetic basis and could serve as raw material for natural selection. Copyright © 2015, American Association for the Advancement of Science.

A review of financial instruments to pay for predator conservation and encourage human–carnivore coexistence

PubMed Central

Dickman, Amy J.; Macdonald, Ewan A.; Macdonald, David W.

2011-01-01

One of the greatest challenges in biodiversity conservation today is how to facilitate protection of species that are highly valued at a global scale but have little or even negative value at a local scale. Imperiled species such as large predators can impose significant economic costs at a local level, often in poverty-stricken rural areas where households are least able to tolerate such costs, and impede efforts of local people, especially traditional pastoralists, to escape from poverty. Furthermore, the costs and benefits involved in predator conservation often include diverse dimensions, which are hard to quantify and nearly impossible to reconcile with one another. The best chance of effective conservation relies upon translating the global value of carnivores into tangible local benefits large enough to drive conservation “on the ground.” Although human–carnivore coexistence involves significant noneconomic values, providing financial incentives to those affected negatively by carnivore presence is a common strategy for encouraging such coexistence, and this can also have important benefits in terms of reducing poverty. Here, we provide a critical overview of such financial instruments, which we term “payments to encourage coexistence”; assess the pitfalls and potentials of these methods, particularly compensation and insurance, revenue-sharing, and conservation payments; and discuss how existing strategies of payment to encourage coexistence could be combined to facilitate carnivore conservation and alleviate local poverty. PMID:21873181

A review of financial instruments to pay for predator conservation and encourage human-carnivore coexistence.

PubMed

Dickman, Amy J; Macdonald, Ewan A; Macdonald, David W

2011-08-23

One of the greatest challenges in biodiversity conservation today is how to facilitate protection of species that are highly valued at a global scale but have little or even negative value at a local scale. Imperiled species such as large predators can impose significant economic costs at a local level, often in poverty-stricken rural areas where households are least able to tolerate such costs, and impede efforts of local people, especially traditional pastoralists, to escape from poverty. Furthermore, the costs and benefits involved in predator conservation often include diverse dimensions, which are hard to quantify and nearly impossible to reconcile with one another. The best chance of effective conservation relies upon translating the global value of carnivores into tangible local benefits large enough to drive conservation "on the ground." Although human-carnivore coexistence involves significant noneconomic values, providing financial incentives to those affected negatively by carnivore presence is a common strategy for encouraging such coexistence, and this can also have important benefits in terms of reducing poverty. Here, we provide a critical overview of such financial instruments, which we term "payments to encourage coexistence"; assess the pitfalls and potentials of these methods, particularly compensation and insurance, revenue-sharing, and conservation payments; and discuss how existing strategies of payment to encourage coexistence could be combined to facilitate carnivore conservation and alleviate local poverty.

Heat-induced accumulation of protein synthesis elongation factor 1A indicates an important role in heat tolerance in potato

USDA-ARS?s Scientific Manuscript database

Heat stress substantially reduces crop productivity worldwide, and will become more severe due to global warming. Identification of proteins involved in heat stress response may help develop varieties for heat tolerance. Eukaryotic elongation factor 1A (eEF1A) is a cytosolic, multifunctional protei...

Quantifying the efficiency of photoprotection

PubMed Central

2017-01-01

A novel emerging technology for the assessment of the photoprotective ‘power’ of non-photochemical fluorescence quenching (NPQ) has been reviewed and its insightful outcomes are explained using several examples. The principles of the method are described in detail as well as the work undertaken for its justification. This pulse amplitude modulated chlorophyll fluorescence approach has been applied for the past 5 years to quantify the photoprotective effectiveness of the NPQ and the light tolerance in Arabidopsis plants grown under various light conditions, during ontogenetic development as well as in a range of mutants impaired in carotenoid and protein biosynthesis. The future applications of this approach for the assessment of crop plant light tolerance are outlined. The perspective of obtaining detailed information about how the extent of photoinhibition and photoprotection can affect plant development, growth and productivity is highlighted, including the potential for us to predict the influence of environmental elements on plant performance and yield of crops. The novel methodology can be used to build up comprehensive light tolerance databases for various current and emerging varieties of crops that are grown outdoors as well as in artificial light environments, in order to optimize for the best environmental conditions that enable high crop productivity. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’. PMID:28808106

Quantifying capital goods for biological treatment of organic waste.

PubMed

Brogaard, Line K; Petersen, Per H; Nielsen, Peter D; Christensen, Thomas H

2015-02-01

Materials and energy used for construction of anaerobic digestion (AD) and windrow composting plants were quantified in detail. The two technologies were quantified in collaboration with consultants and producers of the parts used to construct the plants. The composting plants were quantified based on the different sizes for the three different types of waste (garden and park waste, food waste and sludge from wastewater treatment) in amounts of 10,000 or 50,000 tonnes per year. The AD plant was quantified for a capacity of 80,000 tonnes per year. Concrete and steel for the tanks were the main materials for the AD plant. For the composting plants, gravel and concrete slabs for the pavement were used in large amounts. To frame the quantification, environmental impact assessments (EIAs) showed that the steel used for tanks at the AD plant and the concrete slabs at the composting plants made the highest contribution to Global Warming. The total impact on Global Warming from the capital goods compared to the operation reported in the literature on the AD plant showed an insignificant contribution of 1-2%. For the composting plants, the capital goods accounted for 10-22% of the total impact on Global Warming from composting. © The Author(s) 2015.

The Quantified Self (QS) Movement and Some Emerging Opportunities for the Educational Technology Field

ERIC Educational Resources Information Center

Lee, Victor R.

2013-01-01

The Quantified Self (QS) movement is a growing global effort to use new mobile and wearable technologies to automatically obtain personal data about everyday activities. The social and material infrastructure associated with the Quantified Self (QS) movement provides a number of ideas that educational technologists should consider incorporating…

An image-guided radiotherapy decision support framework incorporating a Bayesian network and visualization tool.

PubMed

Hargrave, Catriona; Deegan, Timothy; Bednarz, Tomasz; Poulsen, Michael; Harden, Fiona; Mengersen, Kerrie

2018-05-17

To describe a Bayesian network (BN) and complementary visualization tool that aim to support decision-making during online cone-beam computed tomography (CBCT)-based image-guided radiotherapy (IGRT) for prostate cancer patients. The BN was created to represent relationships between observed prostate, proximal seminal vesicle (PSV), bladder and rectum volume variations, an image feature alignment score (FAS TV _ OAR ), delivered dose, and treatment plan compliance (TPC). Variables influencing tumor volume (TV) targeting accuracy such as intrafraction motion, and contouring and couch shift errors were also represented. A score of overall TPC (FAS global ) and factors such as image quality were used to inform the BN output node providing advice about proceeding with treatment. The BN was quantified using conditional probabilities generated from published studies, FAS TV _ OAR /global modeling, and a survey of IGRT decision-making practices. A new IGRT visualization tool (IGRT REV ), in the form of Mollweide projection plots, was developed to provide a global summary of residual errors after online CBCT-planning CT registration. Sensitivity and scenario analyses were undertaken to evaluate the performance of the BN and the relative influence of the network variables on TPC and the decision to proceed with treatment. The IGRT REV plots were evaluated in conjunction with the BN scenario testing, using additional test data generated from retrospective CBCT-planning CT soft-tissue registrations for 13/36 patients whose data were used in the FAS TV _ OAR /global modeling. Modeling of the TV targeting errors resulted in a very low probability of corrected distances between the CBCT and planning CT prostate or PSV volumes being within their thresholds. Strength of influence evaluation with and without the BN TV targeting error nodes indicated that rectum- and bladder-related network variables had the highest relative importance. When the TV targeting error nodes were excluded from the BN, TPC was sensitive to observed PSV and rectum variations while the decision to treat was sensitive to observed prostate and PSV variations. When root nodes were set so the PSV and rectum variations exceeded thresholds, the probability of low TPC increased to 40%. Prostate and PSV variations exceeding thresholds increased the likelihood of repositioning or repeating patient preparation to 43%. Scenario testing using the test data from 13 patients, demonstrated two cases where the BN provided increased high TPC probabilities, despite some of the prostate and PSV volume variation metrics not being within tolerance. The IGRT REV tool was effective in highlighting and quantifying where TV and OAR variations occurred, supporting the BN recommendation to reposition the patient or repeat their bladder and bowel preparation. In another case, the IGRT REV tool was also effective in highlighting where PSV volume variation significantly exceeded tolerance when the BN had indicated to proceed with treatment. This study has demonstrated that both the BN and IGRT REV plots are effective tools for inclusion in a decision support system for online CBCT-based IGRT for prostate cancer patients. Alternate approaches to modeling TV targeting errors need to be explored as well as extension of the BN to support offline IGRT decisions related to adaptive radiotherapy. © 2018 American Association of Physicists in Medicine.

76 FR 18906 - Mancozeb; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-06

... from mancozeb and ETU in food as follows: i. Acute exposure. Quantitative acute dietary exposure and.... Cancer. EPA determines whether quantitative cancer exposure and risk assessments are appropriate for a... quantitative cancer risk assessment is appropriate, cancer risk may be quantified using a linear or nonlinear...

Pollution-induced tolerance to copper of nematode communities in the severely contaminated Restronguet Creek and adjacent estuaries, Cornwall, United Kingdom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Millward, R.N.; Grant, A.

2000-02-01

Pollution-induced community tolerance (PICT) has been proposed as an indicator of the deleterious effects of pollutants on communities in the field. Nematode assemblages were sampled at 10 estuarine sites that ranged from uncontaminated to grossly contaminated with metals. Relative tolerance of these assemblages to Cu was quantified using acute toxicity tests. There were large differences between sites in tolerance to Cu, and copper tolerance was strongly correlated with severity of contamination. Enhanced Cu tolerance occurred at two sites where Cu concentration in sediment was around 180 {micro}g/g but not at a third site, where Cu concentration was 214 {micro}g/g. Thismore » implies a threshold of effects on these nematode communities at {approximately}200 {micro}g/g Cu. Comparison with studies of nematode community composition in these same estuaries indicates that PICT is at least as sensitive as the best available ecological monitoring methods. It is, however, faster to carry out and requires much less taxonomic expertise. The PICT appears to be a sensitive indicator of ecological effects of pollution and has considerable promise as a monitoring tool.« less

The Use of Field and Mesocosm Experiments to Quantify Effects of Physical and Chemical Stressors in Mining-Contaminated Streams.

PubMed

Cadmus, Pete; Clements, William H; Williamson, Jacob L; Ranville, James F; Meyer, Joseph S; Gutiérrez Ginés, María Jesús

2016-07-19

Identifying causal relationships between acid mine drainage (AMD) and ecological responses in the field is challenging. In addition to the direct toxicological effects of elevated metals and reduced pH, mining activities influence aquatic organisms indirectly through physical alterations of habitat. The primary goal of this research was to quantify the relative importance of physical (metal-oxide deposition) and chemical (elevated metal concentrations) stressors on benthic macroinvertebrate communities. Mesocosm experiments conducted with natural assemblages of benthic macroinvertebrates established concentration-response relationships between metals and community structure. Field experiments quantified effects of metal-oxide contaminated substrate and showed significant differences in sensitivity among taxa. To predict the recovery of dominant taxa in the field, we integrated our measures of metal tolerance and substrate tolerance with estimates of drift propensity obtained from the literature. Our estimates of recovery were consistent with patterns observed at downstream recovery sites in the NFCC, which were dominated by caddisflies and baetid mayflies. We conclude that mesocosm and small-scale field experiments, particularly those conducted with natural communities, provide an ecologically realistic complement to laboratory toxicity tests. These experiments also control for the confounding variables associated with field-based approaches, thereby supporting causal relationships between AMD stressors and responses.

Natural genetic variation of freezing tolerance in Arabidopsis.

PubMed

Hannah, Matthew A; Wiese, Dana; Freund, Susanne; Fiehn, Oliver; Heyer, Arnd G; Hincha, Dirk K

2006-09-01

Low temperature is a primary determinant of plant growth and survival. Using accessions of Arabidopsis (Arabidopsis thaliana) originating from Scandinavia to the Cape Verde Islands, we show that freezing tolerance of natural accessions correlates with habitat winter temperatures, identifying low temperature as an important selective pressure for Arabidopsis. Combined metabolite and transcript profiling show that during cold exposure, global changes of transcripts, but not of metabolites, correlate with the ability of Arabidopsis to cold acclimate. There are, however, metabolites and transcripts, including several transcription factors, that correlate with freezing tolerance, indicating regulatory pathways that may be of primary importance for this trait. These data identify that enhanced freezing tolerance is associated with the down-regulation of photosynthesis and hormonal responses and the induction of flavonoid metabolism, provide evidence for naturally increased nonacclimated freezing tolerance due to the constitutive activation of the C-repeat binding factors pathway, and identify candidate transcriptional regulators that correlate with freezing tolerance.

Transcriptome analysis of hexaploid hulless oat in response to salinity stress

PubMed Central

Wu, Bin; Hu, Yani; Huo, Pengjie; Zhang, Qian; Chen, Xin; Zhang, Zongwen

2017-01-01

Background Oat is a cereal crop of global importance used for food, feed, and forage. Understanding salinity stress tolerance mechanisms in plants is an important step towards generating crop varieties that can cope with environmental stresses. To date, little is known about the salt tolerance of oat at the molecular level. To better understand the molecular mechanisms underlying salt tolerance in oat, we investigated the transcriptomes of control and salt-treated oat using RNA-Seq. Results Using Illumina HiSeq 4000 platform, we generated 72,291,032 and 356,891,432 reads from non-stressed control and salt-stressed oat, respectively. Assembly of 64 Gb raw sequence data yielded 128,414 putative unique transcripts with an average length of 1,189 bp. Analysis of the assembled unigenes from the salt stressed and control libraries indicated that about 65,000 unigenes were differentially expressed at different stages. Functional annotation showed that ABC transporters, plant hormone signal transduction, plant-pathogen interactions, starch and sucrose metabolism, arginine and proline metabolism, and other secondary metabolite pathways were enriched under salt stress. Based on the RPKM values of assembled unigenes, 24 differentially expressed genes under salt stress were selected for quantitative RT-PCR validation, which successfully confirmed the results of RNA-Seq. Furthermore, we identified 18,039 simple sequence repeats, which may help further elucidate salt tolerance mechanisms in oat. Conclusions Our global survey of transcriptome profiles of oat plants in response to salt stress provides useful insights into the molecular mechanisms underlying salt tolerance in this crop. These findings also represent a rich resource for further analysis of salt tolerance and for breeding oat with improved salt tolerance through the use of salt-related genes. PMID:28192458

Chlorophyll fluorescence emission as a reporter on cold tolerance in Arabidopsis thaliana accessions

PubMed Central

Mishra, Anamika; Höermiller, Imke I; Heyer, Arnd G; Nedbal, Ladislav

2011-01-01

Non-invasive, high-throughput screening methods are valuable tools in breeding for abiotic stress tolerance in plants. Optical signals such as chlorophyll fluorescence emission can be instrumental in developing new screening techniques. In order to examine the potential of chlorophyll fluorescence to reveal plant tolerance to low temperatures, we used a collection of nine Arabidopsis thaliana accessions and compared their fluorescence features with cold tolerance quantified by the well established electrolyte leakage method on detached leaves. We found that, during progressive cooling, the minimal chlorophyll fluorescence emission rose strongly and that this rise was highly dependent on the cold tolerance of the accessions. Maximum quantum yield of PSII photochemistry and steady state fluorescence normalized to minimal fluorescence were also highly correlated to the cold tolerance measured by the electrolyte leakage method. In order to further increase the capacity of the fluorescence detection to reveal the low temperature tolerance, we applied combinatorial imaging that employs plant classification based on multiple fluorescence features. We found that this method, by including the resolving power of several fluorescence features, can be well employed to detect cold tolerance already at mild sub-zero temperatures. Therefore, there is no need to freeze the screened plants to the largely damaging temperatures of around −15°C. This, together with the method's easy applicability, represents a major advantage of the fluorescence technique over the conventional electrolyte leakage method. PMID:21427532

The Challenges of Global Citizenship: Some Issues for Policy and Practice in Early Childhood

ERIC Educational Resources Information Center

Ebbeck, Marjory

2006-01-01

The recent rise in terrorism around the world has caused families, educators, and indeed everyone to consider again how to help young children grow up tolerant, accepting, and, above all, non-violent. Policies that support a tolerant, inclusive curriculum are essential if children are to survive in the years ahead. Curriculum policies must be…

Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics

PubMed Central

Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

2015-01-01

Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains. PMID:26691589

Skeletal records of community-level bleaching in Porites corals from Palau

NASA Astrophysics Data System (ADS)

Barkley, Hannah C.; Cohen, Anne L.

2016-12-01

Tropical Pacific sea surface temperature is projected to rise an additional 2-3 °C by the end of this century, driving an increase in the frequency and intensity of coral bleaching. With significant global coral reef cover already lost due to bleaching-induced mortality, efforts are underway to identify thermally tolerant coral communities that might survive projected warming. Massive, long-lived corals accrete skeletal bands of anomalously high density in response to episodes of thermal stress. These "stress bands" are potentially valuable proxies for thermal tolerance, but to date their application to questions of community bleaching history has been limited. Ecological surveys recorded bleaching of coral communities across the Palau archipelago during the 1998 and 2010 warm events. Between 2011 and 2015, we extracted skeletal cores from living Porites colonies at 10 sites spanning barrier reef and lagoon environments and quantified the proportion of stress bands present in each population during bleaching years. Across Palau, the prevalence of stress bands tracked the severity of thermal stress, with more stress bands occurring in 1998 (degree heating weeks = 13.57 °C-week) than during the less severe 2010 event (degree heating weeks = 4.86 °C-week). Stress band prevalence also varied by reef type, as more corals on the exposed barrier reef formed stress bands than did corals from sheltered lagoon environments. Comparison of Porites stress band prevalence with bleaching survey data revealed a strong correlation between percent community bleaching and the proportion of colonies with stress bands in each year. Conversely, annual calcification rates did not decline consistently during bleaching years nor did annually resolved calcification histories always track interannual variability in temperature. Our data suggest that stress bands in massive corals contain valuable information about spatial and temporal trends in coral reef bleaching and can aid in conservation efforts to identify temperature-tolerant coral reef communities.

A common-garden experiment to quantify evolutionary processes in copepods: the case of emamectin benzoate resistance in the parasitic sea louse Lepeophtheirus salmonis.

PubMed

Ljungfeldt, Lina Eva Robin; Espedal, Per Gunnar; Nilsen, Frank; Skern-Mauritzen, Mette; Glover, Kevin Alan

2014-05-19

The development of pesticide resistance represents a global challenge to food production. Specifically for the Atlantic salmon aquaculture industry, parasitic sea lice and their developing resistance to delousing chemicals is challenging production. In this study, seventeen full sibling families, established from three strains of Lepeophtheirus salmonis displaying differing backgrounds in emamectin benzoate (EB) tolerance were produced and quantitatively compared under a common-garden experimental design. Lice surviving to the preadult stage were then exposed to EB and finally identified through the application of DNA parentage testing. With the exception of two families (19 and 29%), survival from the infectious copepod to preadult stage was very similar among families (40-50%). In contrast, very large differences in survival following EB exposure were observed among the families (7.9-74%). Family survival post EB exposure was consistent with the EB tolerance characteristics of the strains from which they were established and no negative effect on infection success were detected in association with increased EB tolerance. Two of the lice families that displayed reduced sensitivity to EB were established from a commercial farm that had previously used this chemical. This demonstrates that resistant alleles were present on this farm even though the farm had not reported treatment failure. To our knowledge, this represents the first study where families of any multi-cellular parasite have been established and compared in performance under communal rearing conditions in a common-garden experiment. The system performed in a predictable manner and permitted, for the first time, elucidation of quantitative traits among sea lice families. While this experiment concentrated on, and provided a unique insight into EB sensitivity among lice families, the experimental design represents a novel methodology to experimentally address both resistance development and other evolutionary questions in parasitic copepods.

A common-garden experiment to quantify evolutionary processes in copepods: the case of emamectin benzoate resistance in the parasitic sea louse Lepeophtheirus salmonis

PubMed Central

2014-01-01

Background The development of pesticide resistance represents a global challenge to food production. Specifically for the Atlantic salmon aquaculture industry, parasitic sea lice and their developing resistance to delousing chemicals is challenging production. In this study, seventeen full sibling families, established from three strains of Lepeophtheirus salmonis displaying differing backgrounds in emamectin benzoate (EB) tolerance were produced and quantitatively compared under a common-garden experimental design. Lice surviving to the preadult stage were then exposed to EB and finally identified through the application of DNA parentage testing. Results With the exception of two families (19 and 29%), survival from the infectious copepod to preadult stage was very similar among families (40-50%). In contrast, very large differences in survival following EB exposure were observed among the families (7.9-74%). Family survival post EB exposure was consistent with the EB tolerance characteristics of the strains from which they were established and no negative effect on infection success were detected in association with increased EB tolerance. Two of the lice families that displayed reduced sensitivity to EB were established from a commercial farm that had previously used this chemical. This demonstrates that resistant alleles were present on this farm even though the farm had not reported treatment failure. Conclusions To our knowledge, this represents the first study where families of any multi-cellular parasite have been established and compared in performance under communal rearing conditions in a common-garden experiment. The system performed in a predictable manner and permitted, for the first time, elucidation of quantitative traits among sea lice families. While this experiment concentrated on, and provided a unique insight into EB sensitivity among lice families, the experimental design represents a novel methodology to experimentally address both resistance development and other evolutionary questions in parasitic copepods. PMID:24885085

Multicultural Religious Education in a Trinitarian Perspective

ERIC Educational Resources Information Center

Kim, Hyun-Sook

2012-01-01

Multiculturalism is now confronted with pressures of maintaining a balance between unity and diversity on the one hand and building a global civic culture aiming at civic equality, liberty, toleration, and recognition in a global, transnational community on the other hand. With these difficulties, this article attempts to provide a model of…

Genetic variation for tolerance to terminal heat stress in Dasypyrum villosum

USDA-ARS?s Scientific Manuscript database

Heat stress substantially reduces the grain yield and quality of wheat and poses a major challenge to sustain productivity due to global warming. Across wheat growing regions in the US and globally, wheat often experiences terminal heat stress during the post-flowering period. Dasypyrum villosum, a ...

Global Climate Change and NEPA: The Difficulty with Cumulative Impacts Analysis

DTIC Science & Technology

2008-05-18

This paper will provide a survey of the current requirements under the law for addressing global climate change in NEPA documents, along with various...methodologies for quantifying the potential global climate change impacts of federal actions subject to NEPA.

Cryptic species diversity reveals biogeographic support for the ‘mountain passes are higher in the tropics’ hypothesis

PubMed Central

Gill, B. A.; Kondratieff, B. C.; Casner, K. L.; Encalada, A. C.; Flecker, A. S.; Gannon, D. G.; Ghalambor, C. K.; Guayasamin, J. M.; Poff, N. L.; Simmons, M. P.; Thomas, S. A.; Zamudio, K. R.; Funk, W. C.

2016-01-01

The ‘mountain passes are higher in the tropics’ (MPHT) hypothesis posits that reduced climate variability at low latitudes should select for narrower thermal tolerances, lower dispersal and smaller elevational ranges compared with higher latitudes. These latitudinal differences could increase species richness at low latitudes, but that increase may be largely cryptic, because physiological and dispersal traits isolating populations might not correspond to morphological differences. Yet previous tests of the MPHT hypothesis have not addressed cryptic diversity. We use integrative taxonomy, combining morphology (6136 specimens) and DNA barcoding (1832 specimens) to compare the species richness, cryptic diversity and elevational ranges of mayflies (Ephemeroptera) in the Rocky Mountains (Colorado; approx. 40°N) and the Andes (Ecuador; approx. 0°). We find higher species richness and smaller elevational ranges in Ecuador than Colorado, but only after quantifying and accounting for cryptic diversity. The opposite pattern is found when comparing diversity based on morphology alone, underscoring the importance of uncovering cryptic species to understand global biodiversity patterns. PMID:27306051

Global Expression Profiling of Low Temperature Induced Genes in the Chilling Tolerant Japonica Rice Jumli Marshi

PubMed Central

Chawade, Aakash; Lindlöf, Angelica; Olsson, Björn; Olsson, Olof

2013-01-01

Low temperature is a key factor that limits growth and productivity of many important agronomical crops worldwide. Rice (Oryza sativa L.) is negatively affected already at temperatures below +10°C and is therefore denoted as chilling sensitive. However, chilling tolerant rice cultivars exist and can be commercially cultivated at altitudes up to 3,050 meters with temperatures reaching as low as +4°C. In this work, the global transcriptional response to cold stress (+4°C) was studied in the Nepalese highland variety Jumli Marshi (spp. japonica) and 4,636 genes were identified as significantly differentially expressed within 24 hours of cold stress. Comparison with previously published microarray data from one chilling tolerant and two sensitive rice cultivars identified 182 genes differentially expressed (DE) upon cold stress in all four rice cultivars and 511 genes DE only in the chilling tolerant rice. Promoter analysis of the 182 genes suggests a complex cross-talk between ABRE and CBF regulons. Promoter analysis of the 511 genes identified over-represented ABRE motifs but not DRE motifs, suggesting a role for ABA signaling in cold tolerance. Moreover, 2,101 genes were DE in Jumli Marshi alone. By chromosomal localization analysis, 473 of these cold responsive genes were located within 13 different QTLs previously identified as cold associated. PMID:24349120

Probabilistic structural analysis to quantify uncertainties associated with turbopump blades

NASA Technical Reports Server (NTRS)

Nagpal, Vinod K.; Rubinstein, Robert; Chamis, Christos C.

1987-01-01

A probabilistic study of turbopump blades has been in progress at NASA Lewis Research Center for over the last two years. The objectives of this study are to evaluate the effects of uncertainties in geometry and material properties on the structural response of the turbopump blades to evaluate the tolerance limits on the design. A methodology based on probabilistic approach has been developed to quantify the effects of the random uncertainties. The results of this study indicate that only the variations in geometry have significant effects.

Damage Tolerance and Reliability of Turbine Engine Components

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1999-01-01

A formal method is described to quantify structural damage tolerance and reliability in the presence of multitude of uncertainties in turbine engine components. The method is based at the materials behaviour level where primitive variables with their respective scatters are used to describe the behavior. Computational simulation is then used to propagate those uncertainties to the structural scale where damage tolerance and reliability are usually specified. Several sample cases are described to illustrate the effectiveness, versatility, and maturity of the method. Typical results from these methods demonstrate that the methods are mature and that they can be used for future strategic projections and planning to assure better, cheaper, faster, products for competitive advantages in world markets. These results also indicate that the methods are suitable for predicting remaining life in aging or deteriorating structures.

Damage Tolerance and Reliability of Turbine Engine Components

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1998-01-01

A formal method is described to quantify structural damage tolerance and reliability in the presence of multitude of uncertainties in turbine engine components. The method is based at the materials behavior level where primitive variables with their respective scatters are used to describe that behavior. Computational simulation is then used to propagate those uncertainties to the structural scale where damage tolerance and reliability are usually specified. Several sample cases are described to illustrate the effectiveness, versatility, and maturity of the method. Typical results from these methods demonstrate that the methods are mature and that they can be used for future strategic projections and planning to assure better, cheaper, faster products for competitive advantages in world markets. These results also indicate that the methods are suitable for predicting remaining life in aging or deteriorating structures.

A damage tolerance comparison of IM7/8551 and IM8G/8553 carbon/epoxy composites

NASA Technical Reports Server (NTRS)

Lance, D. G.; Nettles, A. T.

1991-01-01

A damage tolerance study of two new toughened carbon fiber/epoxy resin systems was undertaken as a continuation of ongoing work into screening new opposites for resistance to foreign object impact. This report is intended to be a supplement to NASA TP 3029 in which four new fiber/resin systems were tested for damage tolerance. Instrumented drop weight impact testing was used to inflict damage to 16-ply quasi-isotropic specimens. Instrumented output data and cross-sectional examinations of the damage zone were utilized to quantify the damage. It was found that the two fiber/resin systems tested in this study were much more impact resistant than an untoughened composite such as T300/934, but were not as impact resistant as other materials previously studied.

Global vegetation-fire pattern under different land use and climate conditions

NASA Astrophysics Data System (ADS)

Thonicke, K.; Poulter, B.; Heyder, U.; Gumpenberger, M.; Cramer, W.

2008-12-01

Fire is a process of global significance in the Earth System influencing vegetation dynamics, biogeochemical cycling and biophysical feedbacks. Naturally ignited wildfires have long history in the Earth System. Humans have been using fire to shape the landscape for their purposes for many millenia, sometimes influencing the status of the vegetation remarkably as for example in Mediterranean-type ecosystems. Processes and drivers describing fire danger, ignitions, fire spread and effects are relatively well-known for many fire-prone ecosystems. Modeling these has a long tradition in fire-affected regions to predict fire risk and behavior for fire-fighting purposes. On the other hand, the global vegetation community realized the importance of disturbances to be recognized in their global vegetation models with fire being globally most important and so-far best studied. First attempts to simulate fire globally considered a minimal set of drivers, whereas recent developments attempt to consider each fire process separately. The process-based fire model SPITFIRE (SPread and InTensity of FIRE) simulates these processes embedded in the LPJ DGVM. Uncertainties still arise from missing measurements for some parameters in less-studied fire regimes, or from broad PFT classifications which subsume different fire-ecological adaptations and tolerances. Some earth observation data sets as well as fire emission models help to evaluate seasonality and spatial distribution of simulated fire ignitions, area burnt and fire emissions within SPITFIRE. Deforestation fires are a major source of carbon released to the atmosphere in the tropics; in the Amazon basin it is the second-largest contributor to Brazils GHG emissions. How ongoing deforestation affects fire regimes, forest stability and biogeochemical cycling in the Amazon basin under present climate conditions will be presented. Relative importance of fire vs. climate and land use change is analyzed. Emissions resulting from wildfires, agricultural and woodfuel burning will be quantified and drivers identified. Future projections of climate and land use change are applied to the model to investigate joint effects on future changes in fire, deforestation and vegetation dynamics in the Amazon basin.

78 FR 46274 - Pyroxasulfone; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-31

... following a 4-week dermal exposure producing local inflammation and systemic effects of minimal to mild...- linear approach (i.e., Reference dose (RfD)) will adequately account for all chronic toxicity, including... and other relevant data. Cancer risk is quantified using a linear or nonlinear approach. If sufficient...

Impact of local and non-local sources of pollution on background US Ozone: synergy of a low-earth orbiting and geostationary sounder constellation

NASA Astrophysics Data System (ADS)

Bowman, K. W.; Lee, M.

2015-12-01

Dramatic changes in the global distribution of emissions over the last decade have fundamentally altered source-receptor pollution impacts. A new generation of low-earth orbiting (LEO) sounders complimented by geostationary sounders over North America, Europe, and Asia providing a unique opportunity to quantify the current and future trajectory of emissions and their impact on global pollution. We examine the potential of this constellation of air quality sounders to quantify the role of local and non-local sources of pollution on background ozone in the US. Based upon an adjoint sensitivity method, we quantify the role synoptic scale transport of non-US pollution on US background ozone over months representative of different source-receptor relationships. This analysis allows us distinguish emission trajectories from megacities, e.g. Beijing, or regions, e.g., western China, from natural trends on downwind ozone. We subsequently explore how a combination of LEO and GEO observations could help quantify the balance of local emissions against changes in distant sources . These results show how this unprecedented new international ozone observing system can monitor the changing structure of emissions and their impact on global pollution.

Global Fitness Profiling Identifies Arsenic and Cadmium Tolerance Mechanisms in Fission Yeast.

PubMed

Guo, Lan; Ganguly, Abantika; Sun, Lingling; Suo, Fang; Du, Li-Lin; Russell, Paul

2016-10-13

Heavy metals and metalloids such as cadmium [Cd(II)] and arsenic [As(III)] are widespread environmental toxicants responsible for multiple adverse health effects in humans. However, the molecular mechanisms underlying metal-induced cytotoxicity and carcinogenesis, as well as the detoxification and tolerance pathways, are incompletely understood. Here, we use global fitness profiling by barcode sequencing to quantitatively survey the Schizosaccharomyces pombe haploid deletome for genes that confer tolerance of cadmium or arsenic. We identified 106 genes required for cadmium resistance and 110 genes required for arsenic resistance, with a highly significant overlap of 36 genes. A subset of these 36 genes account for almost all proteins required for incorporating sulfur into the cysteine-rich glutathione and phytochelatin peptides that chelate cadmium and arsenic. A requirement for Mms19 is explained by its role in directing iron-sulfur cluster assembly into sulfite reductase as opposed to promoting DNA repair, as DNA damage response genes were not enriched among those required for cadmium or arsenic tolerance. Ubiquinone, siroheme, and pyridoxal 5'-phosphate biosynthesis were also identified as critical for Cd/As tolerance. Arsenic-specific pathways included prefoldin-mediated assembly of unfolded proteins and protein targeting to the peroxisome, whereas cadmium-specific pathways included plasma membrane and vacuolar transporters, as well as Spt-Ada-Gcn5-acetyltransferase (SAGA) transcriptional coactivator that controls expression of key genes required for cadmium tolerance. Notable differences are apparent with corresponding screens in the budding yeast Saccharomyces cerevisiae, underscoring the utility of analyzing toxic metal defense mechanisms in both organisms. Copyright © 2016 Guo et al.

Linking waterlogging tolerance with Mn²⁺ toxicity: a case study for barley.

PubMed

Huang, X; Shabala, S; Shabala, L; Rengel, Z; Wu, X; Zhang, G; Zhou, M

2015-01-01

Vast agricultural areas are affected by flooding, causing up to 80% yield reduction and resulting in multibillion dollar losses. Up to now, the focus of plant breeders was predominantly on detrimental effects of anoxia, while other (potentially equally important) traits were essentially neglected; one of these is soil elemental toxicity. Excess water triggers a progressive decrease in soil redox potential, thus increasing the concentration of Mn(2+) that can be toxic to plants if above a specific threshold. This work aimed to quantify the relative contribution of Mn(2+) toxicity to waterlogging stress tolerance, using barley as a case study. Twenty barley (Hordeum vulgare) genotypes contrasting in waterlogging stress tolerance were studied for their ability to cope with toxic (1 mm) amounts of Mn(2+) in the root rhizosphere. Under Mn(2+) toxicity, chlorophyll content of most waterlogging-tolerant genotypes (TX9425, Yerong, CPI-71284-48 and CM72) remained above 60% of the control value, whereas sensitive genotypes (Franklin and Naso Nijo) had 35% less chlorophyll than 35% of controls. Manganese concentration in leaves was not related to visual Mn(2+) toxicity symptoms, suggesting that various Mn(2+) tolerance mechanisms might operate in different tolerant genotypes, i.e. avoidance versus tissue tolerance. The overall significant (r = 0.60) correlation between tolerance to Mn(2+) toxicity and waterlogging in barley suggests that plant breeding for tolerance to waterlogging traits may be advanced by targeting mechanisms conferring tolerance to Mn(2+) toxicity, at least in this species. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Limited tolerance by insects to high temperatures across tropical elevational gradients and the implications of global warming for extinction.

PubMed

García-Robledo, Carlos; Kuprewicz, Erin K; Staines, Charles L; Erwin, Terry L; Kress, W John

2016-01-19

The critical thermal maximum (CTmax), the temperature at which motor control is lost in animals, has the potential to determine if species will tolerate global warming. For insects, tolerance to high temperatures decreases with latitude, suggesting that similar patterns may exist along elevational gradients as well. This study explored how CTmax varies among species and populations of a group of diverse tropical insect herbivores, the rolled-leaf beetles, across both broad and narrow elevational gradients. Data from 6,948 field observations and 8,700 museum specimens were used to map the elevational distributions of rolled-leaf beetles on two mountains in Costa Rica. CTmax was determined for 1,252 individual beetles representing all populations across the gradients. Initial morphological identifications suggested a total of 26 species with populations at different elevations displaying contrasting upper thermal limits. However, compared with morphological identifications, DNA barcodes (cytochrome oxidase I) revealed significant cryptic species diversity. DNA barcodes identified 42 species and haplotypes across 11 species complexes. These 42 species displayed much narrower elevational distributions and values of CTmax than the 26 morphologically defined species. In general, species found at middle elevations and on mountaintops are less tolerant to high temperatures than species restricted to lowland habitats. Species with broad elevational distributions display high CTmax throughout their ranges. We found no significant phylogenetic signal in CTmax, geography, or elevational range. The narrow variance in CTmax values for most rolled-leaf beetles, especially high-elevation species, suggests that the risk of extinction of insects may be substantial under some projected rates of global warming.

Limited tolerance by insects to high temperatures across tropical elevational gradients and the implications of global warming for extinction

PubMed Central

García-Robledo, Carlos; Kuprewicz, Erin K.; Staines, Charles L.; Erwin, Terry L.; Kress, W. John

2016-01-01

The critical thermal maximum (CTmax), the temperature at which motor control is lost in animals, has the potential to determine if species will tolerate global warming. For insects, tolerance to high temperatures decreases with latitude, suggesting that similar patterns may exist along elevational gradients as well. This study explored how CTmax varies among species and populations of a group of diverse tropical insect herbivores, the rolled-leaf beetles, across both broad and narrow elevational gradients. Data from 6,948 field observations and 8,700 museum specimens were used to map the elevational distributions of rolled-leaf beetles on two mountains in Costa Rica. CTmax was determined for 1,252 individual beetles representing all populations across the gradients. Initial morphological identifications suggested a total of 26 species with populations at different elevations displaying contrasting upper thermal limits. However, compared with morphological identifications, DNA barcodes (cytochrome oxidase I) revealed significant cryptic species diversity. DNA barcodes identified 42 species and haplotypes across 11 species complexes. These 42 species displayed much narrower elevational distributions and values of CTmax than the 26 morphologically defined species. In general, species found at middle elevations and on mountaintops are less tolerant to high temperatures than species restricted to lowland habitats. Species with broad elevational distributions display high CTmax throughout their ranges. We found no significant phylogenetic signal in CTmax, geography, or elevational range. The narrow variance in CTmax values for most rolled-leaf beetles, especially high-elevation species, suggests that the risk of extinction of insects may be substantial under some projected rates of global warming. PMID:26729867

Physiological constraints on organismal response to global warming: Mechanistic insights from clinally varying populations and implications for assessing endangerment.

PubMed

Bernardo, Joseph; Spotila, James R

2006-03-22

Recent syntheses indicate that global warming affects diverse biological processes, but also highlight the potential for some species to adapt behaviourally or evolutionarily to rapid climate change. Far less attention has addressed the alternative, that organisms lacking this ability may face extinction, a fate projected to befall one-quarter of global biodiversity. This conclusion is controversial, in part because there exist few mechanistic studies that show how climate change could precipitate extinction. We provide a concrete, mechanistic example of warming as a stressor of organisms that are closely adapted to cool climates from a comparative analysis of organismal tolerance among clinally varying populations along a natural thermal gradient. We found that two montane salamanders exhibit significant metabolic depression at temperatures within the natural thermal range experienced by low and middle elevation populations. Moreover, the magnitude of depression was inversely related to native elevation, suggesting that low elevation populations are already living near the limit of their physiological tolerances. If this finding generally applies to other montane specialists, the prognosis for biodiversity loss in typically diverse montane systems is sobering. We propose that indices of warming-induced stress tolerance may provide a critical new tool for quantitative assessments of endangerment due to anthropogenic climate change across diverse species.

SU-D-201-01: A Multi-Institutional Study Quantifying the Impact of Simulated Linear Accelerator VMAT Errors for Nasopharynx

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pogson, E; Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW; Ingham Institute for Applied Medical Research, Sydney, NSW

Purpose: To quantify the impact of differing magnitudes of simulated linear accelerator errors on the dose to the target volume and organs at risk for nasopharynx VMAT. Methods: Ten nasopharynx cancer patients were retrospectively replanned twice with one full arc VMAT by two institutions. Treatment uncertainties (gantry angle and collimator in degrees, MLC field size and MLC shifts in mm) were introduced into these plans at increments of 5,2,1,−1,−2 and −5. This was completed using an in-house Python script within Pinnacle3 and analysed using 3DVH and MatLab. The mean and maximum dose were calculated for the Planning Target Volume (PTV1),more » parotids, brainstem, and spinal cord and then compared to the original baseline plan. The D1cc was also calculated for the spinal cord and brainstem. Patient average results were compared across institutions. Results: Introduced gantry angle errors had the smallest effect of dose, no tolerances were exceeded for one institution, and the second institutions VMAT plans were only exceeded for gantry angle of ±5° affecting different sided parotids by 14–18%. PTV1, brainstem and spinal cord tolerances were exceeded for collimator angles of ±5 degrees, MLC shifts and MLC field sizes of ±1 and beyond, at the first institution. At the second institution, sensitivity to errors was marginally higher for some errors including the collimator error producing doses exceeding tolerances above ±2 degrees, and marginally lower with tolerances exceeded above MLC shifts of ±2. The largest differences occur with MLC field sizes, with both institutions reporting exceeded tolerances, for all introduced errors (±1 and beyond). Conclusion: The plan robustness for VMAT nasopharynx plans has been demonstrated. Gantry errors have the least impact on patient doses, however MLC field sizes exceed tolerances even with relatively low introduced errors and also produce the largest errors. This was consistent across both departments. The authors acknowledge funding support from the NSW Cancer Council.« less

Distributed asynchronous microprocessor architectures in fault tolerant integrated flight systems

NASA Technical Reports Server (NTRS)

Dunn, W. R.

1983-01-01

The paper discusses the implementation of fault tolerant digital flight control and navigation systems for rotorcraft application. It is shown that in implementing fault tolerance at the systems level using advanced LSI/VLSI technology, aircraft physical layout and flight systems requirements tend to define a system architecture of distributed, asynchronous microprocessors in which fault tolerance can be achieved locally through hardware redundancy and/or globally through application of analytical redundancy. The effects of asynchronism on the execution of dynamic flight software is discussed. It is shown that if the asynchronous microprocessors have knowledge of time, these errors can be significantly reduced through appropiate modifications of the flight software. Finally, the papear extends previous work to show that through the combined use of time referencing and stable flight algorithms, individual microprocessors can be configured to autonomously tolerate intermittent faults.

Tolerance and potential for adaptation of a Baltic Sea rockweed under predicted climate change conditions.

PubMed

Rugiu, Luca; Manninen, Iita; Rothäusler, Eva; Jormalainen, Veijo

2018-03-01

Climate change is threating species' persistence worldwide. To predict species responses to climate change we need information not just on their environmental tolerance but also on its adaptive potential. We tested how the foundation species of rocky littoral habitats, Fucus vesiculosus, responds to combined hyposalinity and warming projected to the Baltic Sea by 2070-2099. We quantified responses of replicated populations originating from the entrance, central, and marginal Baltic regions. Using replicated individuals, we tested for the presence of within-population tolerance variation. Future conditions hampered growth and survival of the central and marginal populations whereas the entrance populations fared well. Further, both the among- and within-population variation in responses to climate change indicated existence of genetic variation in tolerance. Such standing genetic variation provides the raw material necessary for adaptation to a changing environment, which may eventually ensure the persistence of the species in the inner Baltic Sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tolerance to heavy metals in filamentous fungi isolated from contaminated mining soils in the Zanjan Province, Iran.

PubMed

Mohammadian, Elham; Babai Ahari, Asadollah; Arzanlou, Mahdi; Oustan, Shahin; Khazaei, Sayyed Hossein

2017-10-01

In the present study the population of fungi inhabiting metal contaminated soil samples from lead-zinc mining area was investigated, and their tolerance and biosorption capacity towards Cd, Pb, Zn and Cu were evaluated. Fungal species, including Acremonium persicinum, Penicillium simplicissimum, Seimatosporium pistaciae, Trichoderma harzianum, Alternaria chlamydosporigena and Fusarium verticillioides were isolated. Fungal tolerance was determined by measuring of the "Minimum Inhibitory Concentration", after exposure to increasing concentrations of heavy metal chlorides. Among the test fungi, Trichoderma harzianum was the most tolerant against Cd, Pb and Cu. The Heavy metal content in the fungal biomass was quantified after combustion. The calculated total sorption of heavy metals showed that Acremonium persicinum and Penicillium simplicissimum had the highest accumulation of Zn and Cu, respectively. The data presented in this study should help to use the accumulation potential of some of those fungal species examined for bioremediation of contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phenotypic convergence in bacterial adaptive evolution to ethanol stress.

PubMed

Horinouchi, Takaaki; Suzuki, Shingo; Hirasawa, Takashi; Ono, Naoaki; Yomo, Tetsuya; Shimizu, Hiroshi; Furusawa, Chikara

2015-09-03

Bacterial cells have a remarkable ability to adapt to environmental changes, a phenomenon known as adaptive evolution. During adaptive evolution, phenotype and genotype dynamically changes; however, the relationship between these changes and associated constraints is yet to be fully elucidated. In this study, we analyzed phenotypic and genotypic changes in Escherichia coli cells during adaptive evolution to ethanol stress. Phenotypic changes were quantified by transcriptome and metabolome analyses and were similar among independently evolved ethanol tolerant populations, which indicate the existence of evolutionary constraints in the dynamics of adaptive evolution. Furthermore, the contribution of identified mutations in one of the tolerant strains was evaluated using site-directed mutagenesis. The result demonstrated that the introduction of all identified mutations cannot fully explain the observed tolerance in the tolerant strain. The results demonstrated that the convergence of adaptive phenotypic changes and diverse genotypic changes, which suggested that the phenotype-genotype mapping is complex. The integration of transcriptome and genome data provides a quantitative understanding of evolutionary constraints.

High day- and night-time temperatures affect grain growth dynamics in contrasting rice genotypes.

PubMed

Shi, Wanju; Yin, Xinyou; Struik, Paul C; Solis, Celymar; Xie, Fangming; Schmidt, Ralf C; Huang, Min; Zou, Yingbin; Ye, Changrong; Jagadish, S V Krishna

2017-11-02

Rice grain yield and quality are predicted to be highly vulnerable to global warming. Five genotypes including heat-tolerant and susceptible checks, a heat-tolerant near-isogenic line and two hybrids were exposed to control (31 °C/23 °C, day/night), high night-time temperature (HNT; 31 °C/30 °C), high day-time temperature (HDT; 38 °C/23 °C) and high day- and night-time temperature (HNDT; 38 °C/30 °C) treatments for 20 consecutive days during the grain-filling stage. Grain-filling dynamics, starch metabolism enzymes, temporal starch accumulation patterns and the process of chalk formation were quantified. Compensation between the rate and duration of grain filling minimized the impact of HNT, but irreversible impacts on seed-set, grain filling and ultimately grain weight were recorded with HDT and HNDT. Scanning electron microscopy demonstrated irregular and smaller starch granule formation affecting amyloplast build-up with HDT and HNDT, while a quicker but normal amylopast build-up was recorded with HNT. Our findings revealed temporal variation in the starch metabolism enzymes in all three stress treatments. Changes in the enzymatic activity did not derail starch accumulation under HNT when assimilates were sufficiently available, while both sucrose supply and the conversion of sucrose into starch were affected by HDT and HNDT. The findings indicate differential mechanisms leading to high day and high night temperature stress-induced loss in yield and quality. Additional genetic improvement is needed to sustain rice productivity and quality under future climates. © Society for Experimental Biology 2017.

Contaminant levels in Norwegian farmed Atlantic salmon (Salmo salar) in the 13-year period from 1999 to 2011.

PubMed

Nøstbakken, Ole Jakob; Hove, Helge T; Duinker, Arne; Lundebye, Anne-Katrine; Berntssen, Marc H G; Hannisdal, Rita; Lunestad, Bjørn Tore; Maage, Amund; Madsen, Lise; Torstensen, Bente E; Julshamn, Kåre

2015-01-01

Environmental pollutants such as dioxins and PCBs, heavy metals, and organochlorine pesticides are a global threat to food safety. In particular, the aquatic biota can bioaccumulate many of these contaminants potentially making seafood of concern for chronic exposure to humans. The main objective was to evaluate trends of contaminant levels in Norwegian farmed Atlantic salmon in light of the derived tolerable intakes. Through an EU-instigated surveillance programme, the Norwegian Food Safety Authority (NFSA) has between 1999 and 2011 collected more than 2300 samples of Norwegian farmed Atlantic salmon (Salmo salar) for contaminant analyses. The fillets of these fish were homogenised and analysed for dioxins, PCBs, heavy metals and organochlorine pesticides. The levels of the contaminants mercury, arsenic, dioxins, dioxin-like PCBs and DDT in Norwegian farmed salmon fillet have decreased during our period of analyses. The levels of cadmium, lead and several organochlorine pesticides were too close to the limit of quantification to calculate time trends. For PCB6 and quantifiable amounts of pesticides, except DDT, stable levels were observed. The contaminant levels in Norwegian farmed salmon have generally decreased between 1999 and 2011. Excluding other dietary sources, the levels of dioxins and dioxin-like PCBs in 2011 allowed consumption of up to 1.3kg salmon per week to reach the tolerable weekly intake. The group of contaminants which was the limiting factor for safe consumption of Norwegian farmed salmon, based on currently established TWI values, is the sum of dioxins and dioxin-like PCBs. Copyright © 2014. Published by Elsevier Ltd.

GIBBs: A new soil biology index to quantify beneficial bacteria in the soil

USDA-ARS?s Scientific Manuscript database

Microbial diversity has been linked to soil resilience and health but few microbial indices explicitly link diversity to function. Many of the thousands of bacteria species present in soils enhance plant nutrition, confer stress tolerance, and promote plant growth and productivity through specific m...

Reproductive sink of sweet corn in response to plant density and hybrid

USDA-ARS?s Scientific Manuscript database

Improvements in plant density tolerance have played an essential role in grain corn yield gains for ~80 years; however, plant density effects on sweet corn biomass allocation to the ear (the reproductive ‘sink’) is poorly quantified. Moreover, optimal plant densities for modern white-kernel shrunke...

MaizeGDB: Global support for maize research through open access information [abstract

USDA-ARS?s Scientific Manuscript database

MaizeGDB is the open-access global repository for maize genetic and genomic information – from single genes that determine nutritional quality to whole genome-scale data for complex traits including yield and drought tolerance. The data and tools at MaizeGDB enable researchers from Ethiopia to Ghan...

Global Issues in the Intermediate Classroom: Grades 5-8. Revised Edition.

ERIC Educational Resources Information Center

Johnson, Jacquelyn; And Others

Presenting concepts and information related to global issues at an early age is important in developing an understanding of and tolerance for other cultures. Seeing other peoples' commonalities can help break down the myths and stereotypes that form around groups who are perceived as "strange" and encourage open attitudes toward new…

Evolutionary potential of upper thermal tolerance: biogeographic patterns and expectations under climate change.

PubMed

Diamond, Sarah E

2017-02-01

How will organisms respond to climate change? The rapid changes in global climate are expected to impose strong directional selection on fitness-related traits. A major open question then is the potential for adaptive evolutionary change under these shifting climates. At the most basic level, evolutionary change requires the presence of heritable variation and natural selection. Because organismal tolerances of high temperature place an upper bound on responding to temperature change, there has been a surge of research effort on the evolutionary potential of upper thermal tolerance traits. Here, I review the available evidence on heritable variation in upper thermal tolerance traits, adopting a biogeographic perspective to understand how heritability of tolerance varies across space. Specifically, I use meta-analytical models to explore the relationship between upper thermal tolerance heritability and environmental variability in temperature. I also explore how variation in the methods used to obtain these thermal tolerance heritabilities influences the estimation of heritable variation in tolerance. I conclude by discussing the implications of a positive relationship between thermal tolerance heritability and environmental variability in temperature and how this might influence responses to future changes in climate. © 2016 New York Academy of Sciences.

Quantifying the Effects of Historical Land Cover Conversion Uncertainty on Global Carbon and Climate Estimates

NASA Astrophysics Data System (ADS)

Di Vittorio, A. V.; Mao, J.; Shi, X.; Chini, L.; Hurtt, G.; Collins, W. D.

2018-01-01

Previous studies have examined land use change as a driver of global change, but the translation of land use change into land cover conversion has been largely unconstrained. Here we quantify the effects of land cover conversion uncertainty on the global carbon and climate system using the integrated Earth System Model. Our experiments use identical land use change data and vary land cover conversions to quantify associated uncertainty in carbon and climate estimates. Land cover conversion uncertainty is large, constitutes a 5 ppmv range in estimated atmospheric CO2 in 2004, and generates carbon uncertainty that is equivalent to 80% of the net effects of CO2 and climate and 124% of the effects of nitrogen deposition during 1850-2004. Additionally, land cover uncertainty generates differences in local surface temperature of over 1°C. We conclude that future studies addressing land use, carbon, and climate need to constrain and reduce land cover conversion uncertainties.

Quantifying the Effects of Historical Land Cover Conversion Uncertainty on Global Carbon and Climate Estimates

DOE PAGES

Di Vittorio, A. V.; Mao, J.; Shi, X.; ...

2018-01-03

Previous studies have examined land use change as a driver of global change, but the translation of land use change into land cover conversion has been largely unconstrained. In this paper, we quantify the effects of land cover conversion uncertainty on the global carbon and climate system using the integrated Earth System Model. Our experiments use identical land use change data and vary land cover conversions to quantify associated uncertainty in carbon and climate estimates. Land cover conversion uncertainty is large, constitutes a 5 ppmv range in estimated atmospheric CO 2 in 2004, and generates carbon uncertainty that is equivalentmore » to 80% of the net effects of CO 2 and climate and 124% of the effects of nitrogen deposition during 1850–2004. Additionally, land cover uncertainty generates differences in local surface temperature of over 1°C. Finally, we conclude that future studies addressing land use, carbon, and climate need to constrain and reduce land cover conversion uncertainties.« less

Quantifying the Effects of Historical Land Cover Conversion Uncertainty on Global Carbon and Climate Estimates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Vittorio, A. V.; Mao, J.; Shi, X.

Previous studies have examined land use change as a driver of global change, but the translation of land use change into land cover conversion has been largely unconstrained. In this paper, we quantify the effects of land cover conversion uncertainty on the global carbon and climate system using the integrated Earth System Model. Our experiments use identical land use change data and vary land cover conversions to quantify associated uncertainty in carbon and climate estimates. Land cover conversion uncertainty is large, constitutes a 5 ppmv range in estimated atmospheric CO 2 in 2004, and generates carbon uncertainty that is equivalentmore » to 80% of the net effects of CO 2 and climate and 124% of the effects of nitrogen deposition during 1850–2004. Additionally, land cover uncertainty generates differences in local surface temperature of over 1°C. Finally, we conclude that future studies addressing land use, carbon, and climate need to constrain and reduce land cover conversion uncertainties.« less

Integrating metabolic performance, thermal tolerance, and plasticity enables for more accurate predictions on species vulnerability to acute and chronic effects of global warming.

PubMed

Magozzi, Sarah; Calosi, Piero

2015-01-01

Predicting species vulnerability to global warming requires a comprehensive, mechanistic understanding of sublethal and lethal thermal tolerances. To date, however, most studies investigating species physiological responses to increasing temperature have focused on the underlying physiological traits of either acute or chronic tolerance in isolation. Here we propose an integrative, synthetic approach including the investigation of multiple physiological traits (metabolic performance and thermal tolerance), and their plasticity, to provide more accurate and balanced predictions on species and assemblage vulnerability to both acute and chronic effects of global warming. We applied this approach to more accurately elucidate relative species vulnerability to warming within an assemblage of six caridean prawns occurring in the same geographic, hence macroclimatic, region, but living in different thermal habitats. Prawns were exposed to four incubation temperatures (10, 15, 20 and 25 °C) for 7 days, their metabolic rates and upper thermal limits were measured, and plasticity was calculated according to the concept of Reaction Norms, as well as Q10 for metabolism. Compared to species occupying narrower/more stable thermal niches, species inhabiting broader/more variable thermal environments (including the invasive Palaemon macrodactylus) are likely to be less vulnerable to extreme acute thermal events as a result of their higher upper thermal limits. Nevertheless, they may be at greater risk from chronic exposure to warming due to the greater metabolic costs they incur. Indeed, a trade-off between acute and chronic tolerance was apparent in the assemblage investigated. However, the invasive species P. macrodactylus represents an exception to this pattern, showing elevated thermal limits and plasticity of these limits, as well as a high metabolic control. In general, integrating multiple proxies for species physiological acute and chronic responses to increasing temperature helps providing more accurate predictions on species vulnerability to warming. © 2014 John Wiley & Sons Ltd.

Quantifying the causes of differences in tropospheric OH within global models

NASA Astrophysics Data System (ADS)

Nicely, Julie M.; Salawitch, Ross J.; Canty, Timothy; Anderson, Daniel C.; Arnold, Steve R.; Chipperfield, Martyn P.; Emmons, Louisa K.; Flemming, Johannes; Huijnen, Vincent; Kinnison, Douglas E.; Lamarque, Jean-François; Mao, Jingqiu; Monks, Sarah A.; Steenrod, Stephen D.; Tilmes, Simone; Turquety, Solene

2017-02-01

The hydroxyl radical (OH) is the primary daytime oxidant in the troposphere and provides the main loss mechanism for many pollutants and greenhouse gases, including methane (CH4). Global mean tropospheric OH differs by as much as 80% among various global models, for reasons that are not well understood. We use neural networks (NNs), trained using archived output from eight chemical transport models (CTMs) that participated in the Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols and Transport Model Intercomparison Project (POLMIP), to quantify the factors responsible for differences in tropospheric OH and resulting CH4 lifetime (τCH4) between these models. Annual average τCH4, for loss by OH only, ranges from 8.0 to 11.6 years for the eight POLMIP CTMs. The factors driving these differences were quantified by inputting 3-D chemical fields from one CTM into the trained NN of another CTM. Across all CTMs, the largest mean differences in τCH4 (ΔτCH4) result from variations in chemical mechanisms (ΔτCH4 = 0.46 years), the photolysis frequency (J) of O3 → O(1D) (0.31 years), local O3 (0.30 years), and CO (0.23 years). The ΔτCH4 due to CTM differences in NOx (NO + NO2) is relatively low (0.17 years), although large regional variation in OH between the CTMs is attributed to NOx. Differences in isoprene and J(NO2) have negligible overall effect on globally averaged tropospheric OH, although the extent of OH variations due to each factor depends on the model being examined. This study demonstrates that NNs can serve as a useful tool for quantifying why tropospheric OH varies between global models, provided that essential chemical fields are archived.

An ensemble-based dynamic Bayesian averaging approach for discharge simulations using multiple global precipitation products and hydrological models

NASA Astrophysics Data System (ADS)

Qi, Wei; Liu, Junguo; Yang, Hong; Sweetapple, Chris

2018-03-01

Global precipitation products are very important datasets in flow simulations, especially in poorly gauged regions. Uncertainties resulting from precipitation products, hydrological models and their combinations vary with time and data magnitude, and undermine their application to flow simulations. However, previous studies have not quantified these uncertainties individually and explicitly. This study developed an ensemble-based dynamic Bayesian averaging approach (e-Bay) for deterministic discharge simulations using multiple global precipitation products and hydrological models. In this approach, the joint probability of precipitation products and hydrological models being correct is quantified based on uncertainties in maximum and mean estimation, posterior probability is quantified as functions of the magnitude and timing of discharges, and the law of total probability is implemented to calculate expected discharges. Six global fine-resolution precipitation products and two hydrological models of different complexities are included in an illustrative application. e-Bay can effectively quantify uncertainties and therefore generate better deterministic discharges than traditional approaches (weighted average methods with equal and varying weights and maximum likelihood approach). The mean Nash-Sutcliffe Efficiency values of e-Bay are up to 0.97 and 0.85 in training and validation periods respectively, which are at least 0.06 and 0.13 higher than traditional approaches. In addition, with increased training data, assessment criteria values of e-Bay show smaller fluctuations than traditional approaches and its performance becomes outstanding. The proposed e-Bay approach bridges the gap between global precipitation products and their pragmatic applications to discharge simulations, and is beneficial to water resources management in ungauged or poorly gauged regions across the world.

Future Warming Increases Global Maize Yield Variability with Implications for Food Markets

NASA Astrophysics Data System (ADS)

Tigchelaar, M.; Battisti, D. S.; Naylor, R. L.; Ray, D. K.

2017-12-01

If current trends in population growth and dietary shifts continue, the world will need to produce about 70% more food by 2050, while earth's climate is rapidly changing. Rising temperatures in particular are projected to negatively impact agricultural production, as the world's staple crops perform poorly in extreme heat. Theoretical models suggest that as temperatures rise above plants' optimal temperature for performance, not only will mean yields decline rapidly, but the variability of yields will increase, even as interannual variations in climate remain unchanged. Here we use global datasets of maize production and climate variability combined with CMIP5 temperature projections to quantify how yield variability will change in major maize producing countries under 2°C and 4°C of global warming. Maize is the world's most produced crop, and is linked to other staple crops through substitution in consumption and production. We find that in warmer climates - absent any breeding gains in heat tolerance - the Coefficient of Variation (CV) of maize yields increases almost everywhere, to values much larger than present-day. This increase in CV is due both to an increase in the standard deviation of yields, and a decrease in mean yields. In locations where crop failures become the norm under high (4°C) warming (mostly in tropical, low-yield environments), the standard deviation of yields ultimately decreases. The probability that in any given year the most productive areas in the top three maize producing countries (United States, China, Brazil) have simultaneous production losses greater than 10% is virtually zero under present-day climate conditions, but increases to 12% under 2°C warming, and 89% under 4°C warming. This has major implications for global food markets and staple crop prices, affecting especially the 2.5 billion people that comprise the world's poor, who already spend the majority of their disposable income on food and are particularly vulnerable to agricultural price spikes.

Probabilistic modeling of condition-based maintenance strategies and quantification of its benefits for airliners

NASA Astrophysics Data System (ADS)

Pattabhiraman, Sriram

Airplane fuselage structures are designed with the concept of damage tolerance, wherein small damage are allowed to remain on the airplane, and damage that otherwise affect the safety of the structure are repaired. The damage critical to the safety of the fuselage are repaired by scheduling maintenance at pre-determined intervals. Scheduling maintenance is an interesting trade-off between damage tolerance and cost. Tolerance of larger damage would require less frequent maintenance and hence, a lower cost, to maintain a certain level of reliability. Alternatively, condition-based maintenance techniques have been developed using on-board sensors, which track damage continuously and request maintenance only when the damage size crosses a particular threshold. This effects a tolerance of larger damage than scheduled maintenance, leading to savings in cost. This work quantifies the savings of condition-based maintenance over scheduled maintenance. The work also quantifies converting the cost savings into weight savings. Structural health monitoring will need time to be able to establish itself as a stand-alone system for maintenance, due to concerns on its diagnosis accuracy and reliability. This work also investigates the effect of synchronizing structural health monitoring system with scheduled maintenance. This work uses on-board SHM equipment skip structural airframe maintenance (a subsect of scheduled maintenance), whenever deemed unnecessary while maintain a desired level of safety of structure. The work will also predict the necessary maintenance for a fleet of airplanes, based on the current damage status of the airplanes. The work also analyses the possibility of false alarm, wherein maintenance is being requested with no critical damage on the airplane. The work use SHM as a tool to identify lemons in a fleet of airplanes. Lemons are those airplanes that would warrant more maintenance trips than the average behavior of the fleet.

Quantifying global dust devil occurrence from meteorological analyses

PubMed Central

Jemmett-Smith, Bradley C; Marsham, John H; Knippertz, Peter; Gilkeson, Carl A

2015-01-01

Dust devils and nonrotating dusty plumes are effective uplift mechanisms for fine particles, but their contribution to the global dust budget is uncertain. By applying known bulk thermodynamic criteria to European Centre for Medium-Range Weather Forecasts (ECMWF) operational analyses, we provide the first global hourly climatology of potential dust devil and dusty plume (PDDP) occurrence. In agreement with observations, activity is highest from late morning into the afternoon. Combining PDDP frequencies with dust source maps and typical emission values gives the best estimate of global contributions of 3.4% (uncertainty 0.9–31%), 1 order of magnitude lower than the only estimate previously published. Total global hours of dust uplift by dry convection are ∼0.002% of the dust-lifting winds resolved by ECMWF, consistent with dry convection making a small contribution to global uplift. Reducing uncertainty requires better knowledge of factors controlling PDDP occurrence, source regions, and dust fluxes induced by dry convection. Key Points Global potential dust devil occurrence quantified from meteorological analyses Climatology shows realistic diurnal cycle and geographical distribution Best estimate of global contribution of 3.4% is 10 times smaller than the previous estimate PMID:26681815

Evaluating physiological responses of plants to salinity stress

PubMed Central

Negrão, S.; Schmöckel, S. M.; Tester, M.

2017-01-01

Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making it difficult to study in toto. Instead, it is more tractable to dissect the plant’s response into traits that are hypothesized to be involved in the overall tolerance of the plant to salinity. Scope and conclusions We discuss how to quantify the impact of salinity on different traits, such as relative growth rate, water relations, transpiration, transpiration use efficiency, ionic relations, photosynthesis, senescence, yield and yield components. We also suggest some guidelines to assist with the selection of appropriate experimental systems, imposition of salinity stress, and obtaining and analysing relevant physiological data using appropriate indices. We illustrate how these indices can be used to identify relationships amongst the proposed traits to identify which traits are the most important contributors to salinity tolerance. Salinity tolerance is complex and involves many genes, but progress has been made in studying the mechanisms underlying a plant’s response to salinity. Nevertheless, several previous studies on salinity tolerance could have benefited from improved experimental design. We hope that this paper will provide pertinent information to researchers on performing proficient assays and interpreting results from salinity tolerance experiments. PMID:27707746

Revisiting soil carbon and nitrogen sampling: quantitative pits versus rotary cores

USDA-ARS?s Scientific Manuscript database

Increasing atmospheric carbon dioxide and its feedbacks with global climate have sparked renewed interest in quantifying ecosystem carbon (C) budgets, including quantifying belowground pools. Belowground nutrient budgets require accurate estimates of soil mass, coarse fragment content, and nutrient ...

Etanercept in Alzheimer disease: A randomized, placebo-controlled, double-blind, phase 2 trial.

PubMed

Butchart, Joseph; Brook, Laura; Hopkins, Vivienne; Teeling, Jessica; Püntener, Ursula; Culliford, David; Sharples, Richard; Sharif, Saif; McFarlane, Brady; Raybould, Rachel; Thomas, Rhodri; Passmore, Peter; Perry, V Hugh; Holmes, Clive

2015-05-26

To determine whether the tumor necrosis factor α inhibitor etanercept is well tolerated and obtain preliminary data on its safety in Alzheimer disease dementia. In a double-blind study, patients with mild to moderate Alzheimer disease dementia were randomized (1:1) to subcutaneous etanercept (50 mg) once weekly or identical placebo over a 24-week period. Tolerability and safety of this medication was recorded including secondary outcomes of cognition, global function, behavior, and systemic cytokine levels at baseline, 12 weeks, 24 weeks, and following a 4-week washout period. This trial is registered with EudraCT (2009-013400-31) and ClinicalTrials.gov (NCT01068353). Forty-one participants (mean age 72.4 years; 61% men) were randomized to etanercept (n = 20) or placebo (n = 21). Etanercept was well tolerated; 90% of participants (18/20) completed the study compared with 71% (15/21) in the placebo group. Although infections were more common in the etanercept group, there were no serious adverse events or new safety concerns. While there were some interesting trends that favored etanercept, there were no statistically significant changes in cognition, behavior, or global function. This study showed that subcutaneous etanercept (50 mg/wk) was well tolerated in this small group of patients with Alzheimer disease dementia, but a larger more heterogeneous group needs to be tested before recommending its use for broader groups of patients. This study shows Class I evidence that weekly subcutaneous etanercept is well tolerated in Alzheimer disease dementia. © 2015 American Academy of Neurology.

Field evaluation of green and red leaf lettuce genotypes in the Imperial, San Joaquin, and Salinas Valleys of California for heat tolerance and extension of the growing seasons

USDA-ARS?s Scientific Manuscript database

Global warming poses serious threats and challenges to the production of leafy vegetables. Being a cool-season crop, lettuce is vulnerable to heat-stress. To adapt to climate change, this study was conducted to evaluate the performance of leaf lettuce genotypes for heat tolerance by growing them in ...

Comparative Phosphoproteomics Reveals an Important Role of MKK2 in Banana (Musa spp.) Cold Signal Network

PubMed Central

Gao, Jie; Zhang, Sheng; He, Wei-Di; Shao, Xiu-Hong; Li, Chun-Yu; Wei, Yue-Rong; Deng, Gui-Ming; Kuang, Rui-Bin; Hu, Chun-Hua; Yi, Gan-Jun; Yang, Qiao-Song

2017-01-01

Low temperature is one of the key environmental stresses, which greatly affects global banana production. However, little is known about the global phosphoproteomes in Musa spp. and their regulatory roles in response to cold stress. In this study, we conducted a comparative phosphoproteomic profiling of cold-sensitive Cavendish Banana and relatively cold tolerant Dajiao under cold stress. Phosphopeptide abundances of five phosphoproteins involved in MKK2 interaction network, including MKK2, HY5, CaSR, STN7 and kinesin-like protein, show a remarkable difference between Cavendish Banana and Dajiao in response to cold stress. Western blotting of MKK2 protein and its T31 phosphorylated peptide verified the phosphoproteomic results of increased T31 phosphopeptide abundance with decreased MKK2 abundance in Daojiao for a time course of cold stress. Meanwhile increased expression of MKK2 with no detectable T31 phosphorylation was found in Cavendish Banana. These results suggest that the MKK2 pathway in Dajiao, along with other cold-specific phosphoproteins, appears to be associated with the molecular mechanisms of high tolerance to cold stress in Dajiao. The results also provide new evidence that the signaling pathway of cellular MKK2 phosphorylation plays an important role in abiotic stress tolerance that likely serves as a universal plant cold tolerance mechanism. PMID:28106078

A Sister Group Contrast Using Untargeted Global Metabolomic Analysis Delineates the Biochemical Regulation Underlying Desiccation Tolerance in Sporobolus stapfianus[C][W][OA

PubMed Central

Oliver, Melvin J.; Guo, Lining; Alexander, Danny C.; Ryals, John A.; Wone, Bernard W.M.; Cushman, John C.

2011-01-01

Understanding how plants tolerate dehydration is a prerequisite for developing novel strategies for improving drought tolerance. The desiccation-tolerant (DT) Sporobolus stapfianus and the desiccation-sensitive (DS) Sporobolus pyramidalis formed a sister group contrast to reveal adaptive metabolic responses to dehydration using untargeted global metabolomic analysis. Young leaves from both grasses at full hydration or at 60% relative water content (RWC) and from S. stapfianus at lower RWCs were analyzed using liquid and gas chromatography linked to mass spectrometry or tandem mass spectrometry. Comparison of the two species in the fully hydrated state revealed intrinsic differences between the two metabolomes. S. stapfianus had higher concentrations of osmolytes, lower concentrations of metabolites associated with energy metabolism, and higher concentrations of nitrogen metabolites, suggesting that it is primed metabolically for dehydration stress. Further reduction of the leaf RWC to 60% instigated a metabolic shift in S. stapfianus toward the production of protective compounds, whereas S. pyramidalis responded differently. The metabolomes of S. stapfianus leaves below 40% RWC were strongly directed toward antioxidant production, nitrogen remobilization, ammonia detoxification, and soluble sugar production. Collectively, the metabolic profiles obtained uncovered a cascade of biochemical regulation strategies critical to the survival of S. stapfianus under desiccation. PMID:21467579

Breeding of ozone resistant rice: relevance, approaches and challenges.

PubMed

Frei, Michael

2015-02-01

Tropospheric ozone concentrations have been rising across Asia, and will continue to rise during the 21st century. Ozone affects rice yields through reductions in spikelet number, spikelet fertility, and grain size. Moreover, ozone leads to changes in rice grain and straw quality. Therefore the breeding of ozone tolerant rice varieties is warranted. The mapping of quantitative trait loci (QTL) using bi-parental populations identified several tolerance QTL mitigating symptom formation, grain yield losses, or the degradation of straw quality. A genome-wide association study (GWAS) demonstrated substantial natural genotypic variation in ozone tolerance in rice, and revealed that the genetic architecture of ozone tolerance in rice is dominated by multiple medium and small effect loci. Transgenic approaches targeting tolerance mechanisms such as antioxidant capacity are also discussed. It is concluded that the breeding of ozone tolerant rice can contribute substantially to the global food security, and is feasible using different breeding approaches. Copyright © 2014 Elsevier Ltd. All rights reserved.

The first step toward genetic selection for host tolerance to infectious pathogens: obtaining the tolerance phenotype through group estimates

PubMed Central

Doeschl-Wilson, Andrea B.; Villanueva, Beatriz; Kyriazakis, Ilias

2012-01-01

Reliable phenotypes are paramount for meaningful quantification of genetic variation and for estimating individual breeding values on which genetic selection is based. In this paper, we assert that genetic improvement of host tolerance to disease, although desirable, may be first of all handicapped by the ability to obtain unbiased tolerance estimates at a phenotypic level. In contrast to resistance, which can be inferred by appropriate measures of within host pathogen burden, tolerance is more difficult to quantify as it refers to change in performance with respect to changes in pathogen burden. For this reason, tolerance phenotypes have only been specified at the level of a group of individuals, where such phenotypes can be estimated using regression analysis. However, few stsudies have raised the potential bias in these estimates resulting from confounding effects between resistance and tolerance. Using a simulation approach, we demonstrate (i) how these group tolerance estimates depend on within group variation and co-variation in resistance, tolerance, and vigor (performance in a pathogen free environment); and (ii) how tolerance estimates are affected by changes in pathogen virulence over the time course of infection and by the timing of measurements. We found that in order to obtain reliable group tolerance estimates, it is important to account for individual variation in vigor, if present, and that all individuals are at the same stage of infection when measurements are taken. The latter requirement makes estimation of tolerance based on cross-sectional field data challenging, as individuals become infected at different time points and the individual onset of infection is unknown. Repeated individual measurements of within host pathogen burden and performance would not only be valuable for inferring the infection status of individuals in field conditions, but would also provide tolerance estimates that capture the entire time course of infection. PMID:23412990

Life-history strategies constrain invertebrate community tolerance to multiple stressors: A case study in the Ebro basin.

PubMed

Mondy, Cédric P; Muñoz, Isabel; Dolédec, Sylvain

2016-12-01

Multiple stressors constitute a serious threat to aquatic ecosystems, particularly in the Mediterranean region where water scarcity is likely to interact with other anthropogenic stressors. Biological traits potentially allow the unravelling of the effects of multiple stressors. However, thus far, trait-based approaches have failed to fully deliver on their promise and still lack strong predictive power when multiple stressors are present. We aimed to quantify specific community tolerances against six anthropogenic stressors and investigate the responses of the underlying macroinvertebrate biological traits and their combinations. We built and calibrated boosted regression tree models to predict community tolerances using multiple biological traits with a priori hypotheses regarding their individual responses to specific stressors. We analysed the combinations of traits underlying community tolerance and the effect of trait association on this tolerance. Our results validated the following three hypotheses: (i) the community tolerance models efficiently and robustly related trait combinations to stressor intensities and, to a lesser extent, to stressors related to the presence of dams and insecticides; (ii) the effects of traits on community tolerance not only depended on trait identity but also on the trait associations emerging at the community level from the co-occurrence of different traits in species; and (iii) the community tolerances and the underlying trait combinations were specific to the different stressors. This study takes a further step towards predictive tools in community ecology that consider combinations and associations of traits as the basis of stressor tolerance. Additionally, the community tolerance concept has potential application to help stream managers in the decision process regarding management options. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

The effects of changing climate on faunal depth distributions determine winners and losers.

PubMed

Brown, Alastair; Thatje, Sven

2015-01-01

Changing climate is predicted to impact all depths of the global oceans, yet projections of range shifts in marine faunal distributions in response to changing climate seldom evaluate potential shifts in depth distribution. Marine ectotherms' thermal tolerance is limited by their ability to maintain aerobic metabolism (oxygen- and capacity-limited tolerance), and is functionally associated with their hypoxia tolerance. Shallow-water (<200 m depth) marine invertebrates and fishes demonstrate limited tolerance of increasing hydrostatic pressure (pressure exerted by the overlying mass of water), and hyperbaric (increased pressure) tolerance is proposed to depend on the ability to maintain aerobic metabolism, too. Here, we report significant correlation between the hypoxia thresholds and the hyperbaric thresholds of taxonomic groups of shallow-water fauna, suggesting that pressure tolerance is indeed oxygen limited. Consequently, it appears that the combined effects of temperature, pressure and oxygen concentration constrain the fundamental ecological niches (FENs) of marine invertebrates and fishes. Including depth in a conceptual model of oxygen- and capacity-limited FENs' responses to ocean warming and deoxygenation confirms previous predictions made based solely on consideration of the latitudinal effects of ocean warming (e.g. Cheung et al., 2009), that polar taxa are most vulnerable to the effects of climate change, with Arctic fauna experiencing the greatest FEN contraction. In contrast, the inclusion of depth in the conceptual model reveals for the first time that temperate fauna as well as tropical fauna may experience substantial FEN expansion with ocean warming and deoxygenation, rather than FEN maintenance or contraction suggested by solely considering latitudinal range shifts. © 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Stress tolerance in plants via habitat-adapted symbiosis

USGS Publications Warehouse

Rodriguez, R.J.; Henson, J.; Van Volkenburgh, E.; Hoy, M.; Wright, L.; Beckwith, F.; Kim, Y.-O.; Redman, R.S.

2008-01-01

We demonstrate that native grass species from coastal and geothermal habitats require symbiotic fungal endophytes for salt and heat tolerance, respectively. Symbiotically conferred stress tolerance is a habitat-specific phenomenon with geothermal endophytes conferring heat but not salt tolerance, and coastal endophytes conferring salt but not heat tolerance. The same fungal species isolated from plants in habitats devoid of salt or heat stress did not confer these stress tolerances. Moreover, fungal endophytes from agricultural crops conferred disease resistance and not salt or heat tolerance. We define habitat-specific, symbiotically-conferred stress tolerance as habitat-adapted symbiosis and hypothesize that it is responsible for the establishment of plants in high-stress habitats. The agricultural, coastal and geothermal plant endophytes also colonized tomato (a model eudicot) and conferred disease, salt and heat tolerance, respectively. In addition, the coastal plant endophyte colonized rice (a model monocot) and conferred salt tolerance. These endophytes have a broad host range encompassing both monocots and eudicots. Interestingly, the endophytes also conferred drought tolerance to plants regardless of the habitat of origin. Abiotic stress tolerance correlated either with a decrease in water consumption or reactive oxygen sensitivity/generation but not to increased osmolyte production. The ability of fungal endophytes to confer stress tolerance to plants may provide a novel strategy for mitigating the impacts of global climate change on agricultural and native plant communities.The ISME Journal (2008) 2, 404-416; doi:10.1038/ismej.2007.106; published online 7 February 2008. ?? 2008 International Society for Microbial Ecology All rights reserved.

Alcohol levels do not accurately predict physical or mental impairment in ethanol-tolerant subjects: relevance to emergency medicine and dram shop laws.

PubMed

Roberts, James R; Dollard, Denis

2010-12-01

The human body and the central nervous system can develop tremendous tolerance to ethanol. Mental and physical dysfunctions from ethanol, in an alcohol-tolerant individual, do not consistently correlate with ethanol levels traditionally used to define intoxication, or even lethality, in a nontolerant subject. Attempting to relate observed signs of alcohol intoxication or impairment, or to evaluate sobriety, by quantifying blood alcohol levels can be misleading, if not impossible. We report a case demonstrating the disconnect between alcohol levels and generally assigned parameters of intoxication and impairment. In this case, an alcohol-tolerant man, with a serum ethanol level of 515 mg/dl, appeared neurologically intact and cognitively normal. This individual was without objective signs of impairment or intoxication by repeated evaluations by experienced emergency physicians. In alcohol-tolerant individuals, blood alcohol levels cannot always be predicted by and do not necessarily correlate with outward appearance, overt signs of intoxication, or physical examination. This phenomenon must be acknowledged when analyzing medical decision making in the emergency department or when evaluating the ability of bartenders and party hosts to identify intoxication in dram shop cases.

Global Persistent Attack: A Systems Architecture, Process Modeling, and Risk Analysis Approach

DTIC Science & Technology

2008-06-01

develop an analysis process for quantifying risk associated with the limitations presented by a fiscally constrained environment. The second step...previous independent analysis of each force structure provided information for quantifying risk associated with the given force presentations, the

Global Wind Map

ERIC Educational Resources Information Center

Journal of College Science Teaching, 2005

2005-01-01

This brief article describes a new global wind-power map that has quantified global wind power and may help planners place turbines in locations that can maximize power from the winds and provide widely available low-cost energy. The researchers report that their study can assist in locating wind farms in regions known for strong and consistent…

Quantifying Globalization in Social Work Research: A 10-Year Review of American Social Work Journals

ERIC Educational Resources Information Center

Agbényiga, DeBrenna L.; Huang, Lihua

2014-01-01

Measured by the prevalence of journal article contributions, geographic coverage, and international collaboration, this literature review found an increasing level of globalization with respect to American social work research and contribution to the social work profession from 2000-2009. Findings suggest changes are needed in global awareness and…

Contribution of bioaerosols to the global organic aerosol budget

NASA Astrophysics Data System (ADS)

Janssen, R.; Heald, C. L.

2017-12-01

Bioaerosols are ubiquitous in the atmosphere and may contribute significantly to cloud condensation and ice nuclei populations, and consequently to formation of clouds and precipitation. However, quantifying the contribution of bioaerosols to the global organic aerosol budget is a challenge, since bioaerosol sources are poorly constrained on the global scale. Previous global estimates of global primary biological aerosol particle (PBAP) emissions, including bacteria, fungal spores and pollen, range from 78-296 Tg/year. Over the past several years, size-resolved measurements of fluorescent biological aerosol particles have been made in tropical, temperate and boreal ecosystems. Besides, single particle mass spectroscopy has been used to quantify bioaerosol concentrations at various locations in the US. We use these observations to develop and evaluate a bioaerosol emission scheme that describes both the biological production of bioaerosols and the meteorological drivers of the emission of these particles into the atmosphere. Then, we implement this scheme in the GEOS-Chem global chemical transport model to estimate the emission, burden and lifetime of bioaerosols. Finally, we evaluate the contribution of bioaerosols to the total organic aerosol budget, which further consists of primary and secondary organic aerosol.

Development and Validation of a Multiplexed Protein Quantitation Assay for the Determination of Three Recombinant Proteins in Soybean Tissues by Liquid Chromatography with Tandem Mass Spectrometry.

PubMed

Hill, Ryan C; Oman, Trent J; Shan, Guomin; Schafer, Barry; Eble, Julie; Chen, Cynthia

2015-08-26

Currently, traditional immunochemistry technologies such as enzyme-linked immunosorbent assays (ELISA) are the predominant analytical tool used to measure levels of recombinant proteins expressed in genetically engineered (GE) plants. Recent advances in agricultural biotechnology have created a need to develop methods capable of selectively detecting and quantifying multiple proteins in complex matrices because of increasing numbers of transgenic proteins being coexpressed or "stacked" to achieve tolerance to multiple herbicides or to provide multiple modes of action for insect control. A multiplexing analytical method utilizing liquid chromatography with tandem mass spectrometry (LC-MS/MS) has been developed and validated to quantify three herbicide-tolerant proteins in soybean tissues: aryloxyalkanoate dioxygenase (AAD-12), 5-enol-pyruvylshikimate-3-phosphate synthase (2mEPSPS), and phosphinothricin acetyltransferase (PAT). Results from the validation showed high recovery and precision over multiple analysts and laboratories. Results from this method were comparable to those obtained with ELISA with respect to protein quantitation, and the described method was demonstrated to be suitable for multiplex quantitation of transgenic proteins in GE crops.

Forecasting an invasive species’ distribution with global distribution data, local data, and physiological information

USGS Publications Warehouse

Jarnevich, Catherine S.; Young, Nicholas E.; Talbert, Marian; Talbert, Colin

2018-01-01

Understanding invasive species distributions and potential invasions often requires broad‐scale information on the environmental tolerances of the species. Further, resource managers are often faced with knowing these broad‐scale relationships as well as nuanced environmental factors related to their landscape that influence where an invasive species occurs and potentially could occur. Using invasive buffelgrass (Cenchrus ciliaris), we developed global models and local models for Saguaro National Park, Arizona, USA, based on location records and literature on physiological tolerances to environmental factors to investigate whether environmental relationships of a species at a global scale are also important at local scales. In addition to correlative models with five commonly used algorithms, we also developed a model using a priori user‐defined relationships between occurrence and environmental characteristics based on a literature review. All correlative models at both scales performed well based on statistical evaluations. The user‐defined curves closely matched those produced by the correlative models, indicating that the correlative models may be capturing mechanisms driving the distribution of buffelgrass. Given climate projections for the region, both global and local models indicate that conditions at Saguaro National Park may become more suitable for buffelgrass. Combining global and local data with correlative models and physiological information provided a holistic approach to forecasting invasive species distributions.

Integrity of Cerebellar Fastigial Nucleus Intrinsic Neurons Is Critical for the Global Ischemic Preconditioning

PubMed Central

Regnier-Golanov, Angelique S.; Britz, Gavin W.

2017-01-01

Excitation of intrinsic neurons of cerebellar fastigial nucleus (FN) renders brain tolerant to local and global ischemia. This effect reaches a maximum 72 h after the stimulation and lasts over 10 days. Comparable neuroprotection is observed following sublethal global brain ischemia, a phenomenon known as preconditioning. We hypothesized that FN may participate in the mechanisms of ischemic preconditioning as a part of the intrinsic neuroprotective mechanism. To explore potential significance of FN neurons in brain ischemic tolerance we lesioned intrinsic FN neurons with excitotoxin ibotenic acid five days before exposure to 20 min four-vessel occlusion (4-VO) global ischemia while analyzing neuronal damage in Cornu Ammoni area 1 (CA1) hippocampal area one week later. In FN-lesioned animals, loss of CA1 cells was higher by 22% compared to control (phosphate buffered saline (PBS)-injected) animals. Moreover, lesion of FN neurons increased morbidity following global ischemia by 50%. Ablation of FN neurons also reversed salvaging effects of five-minute ischemic preconditioning on CA1 neurons and morbidity, while ablation of cerebellar dentate nucleus neurons did not change effect of ischemic preconditioning. We conclude that FN is an important part of intrinsic neuroprotective system, which participates in ischemic preconditioning and may participate in naturally occurring neuroprotection, such as “diving response”. PMID:28934119

Risk assessment of sleeping disorder breathing based on upper airway centerline evaluation

NASA Astrophysics Data System (ADS)

Alsufyani, Noura; Shen, Rui; Cheng, Irene; Major, Paul

2013-02-01

One of the most important breathing disorders in childhood is obstructive sleep apnea syndrome which affects 2-3% of children, and the reported failure rate of surgical treatment was as high as 54%. A possible reason in respiratory complications is having reduced dimensions of the upper airway which are further compressed when muscle tone is decreased during sleep. In this study, we use Cone-beam computed tomography (CBCT) to assess the location or cause of the airway obstruction. To date, all studies analyzing the upper airway in subjects with Sleeping Disorder Breathing were based on linear, area, or volumetric measurements, which are global computations and can easily ignore local significance. Skeletonization was initially introduced as a 3D modeling technique by which representative medial points of a model are extracted to generate centerlines for evaluations. Although centerlines have been commonly used in guiding surgical procedures, our novelty lies in comparing its geometric properties before and after surgeries. We apply 3D data refinement, registration and projection steps to quantify and localize the geometric deviation in target airway regions. Through cross validation with corresponding subjects' therapy data, we expect to quantify the tolerance threshold beyond which reduced dimensions of the upper airway are not clinically significant. The ultimate goal is to utilize this threshold to identify patients at risk of complications. Outcome from this research will also help establish a predictive model for training and to estimate treatment success based on airway measurements prior to intervention. Preliminary results demonstrate the feasibility of our approach.

Interocular suppression in amblyopia for global orientation processing.

PubMed

Zhou, Jiawei; Huang, Pi-Chun; Hess, Robert F

2013-04-22

We developed a dichoptic global orientation coherence paradigm to quantify interocular suppression in amblyopia. This task is biased towards ventral processing and allows comparison with two other techniques-global motion processing, which is more dorsally biased, and binocular phase combination, which most likely reflects striate function. We found a similar pattern for the relationship between coherence threshold and interocular contrast curves (thresholds vs. interocular contrast ratios or TvRs) in our new paradigm compared with those of the previous dichoptic global motion coherence paradigm. The effective contrast ratios at balance point (where the signals from the two eyes have equal weighting) in our new paradigm were larger than those of the dichoptic global motion coherence paradigm but less than those of the binocular phase combination paradigm. The measured effective contrast ratios in the three paradigms were also positively correlated with each other, with the two global coherence paradigms having the highest correlation. We concluded that: (a) The dichoptic global orientation coherence paradigm is effective in quantifying interocular suppression in amblyopia; and (b) Interocular suppression, while sharing a common suppression mechanism at the early stage in the pathway (e.g., striate cortex), may have additional extra-striate contributions that affect both dorsal and ventral streams differentially.

Directed combinatorial mutagenesis of Escherichia coli for complex phenotype engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Rongming; Liang, Liya; Garst, Andrew D.

Strain engineering for industrial production requires a targeted improvement of multiple complex traits, which range from pathway flux to tolerance to mixed sugar utilization. Here, we report the use of an iterative CRISPR EnAbled Trackable genome Engineering (iCREATE) method to engineer rapid glucose and xylose co-consumption and tolerance to hydrolysate inhibitors in E. coli. Deep mutagenesis libraries were rationally designed, constructed, and screened to target ~40,000 mutations across 30 genes. These libraries included global and high-level regulators that regulate global gene expression, transcription factors that play important roles in genome-level transcription, enzymes that function in the sugar transport system, NAD(P)Hmore » metabolism, and the aldehyde reduction system. Specific mutants that conferred increased growth in mixed sugars and hydrolysate tolerance conditions were isolated, confirmed, and evaluated for changes in genome-wide expression levels. As a result, we tested the strain with positive combinatorial mutations for 3-hydroxypropionic acid (3HP) production under high furfural and high acetate hydrolysate fermentation, which demonstrated a 7- and 8-fold increase in 3HP productivity relative to the parent strain, respectively.« less

Directed combinatorial mutagenesis of Escherichia coli for complex phenotype engineering

DOE PAGES

Liu, Rongming; Liang, Liya; Garst, Andrew D.; ...

2018-03-29

Strain engineering for industrial production requires a targeted improvement of multiple complex traits, which range from pathway flux to tolerance to mixed sugar utilization. Here, we report the use of an iterative CRISPR EnAbled Trackable genome Engineering (iCREATE) method to engineer rapid glucose and xylose co-consumption and tolerance to hydrolysate inhibitors in E. coli. Deep mutagenesis libraries were rationally designed, constructed, and screened to target ~40,000 mutations across 30 genes. These libraries included global and high-level regulators that regulate global gene expression, transcription factors that play important roles in genome-level transcription, enzymes that function in the sugar transport system, NAD(P)Hmore » metabolism, and the aldehyde reduction system. Specific mutants that conferred increased growth in mixed sugars and hydrolysate tolerance conditions were isolated, confirmed, and evaluated for changes in genome-wide expression levels. As a result, we tested the strain with positive combinatorial mutations for 3-hydroxypropionic acid (3HP) production under high furfural and high acetate hydrolysate fermentation, which demonstrated a 7- and 8-fold increase in 3HP productivity relative to the parent strain, respectively.« less

Global analysis of plasticity in turgor loss point, a key drought tolerance trait.

PubMed

Bartlett, Megan K; Zhang, Ya; Kreidler, Nissa; Sun, Shanwen; Ardy, Rico; Cao, Kunfang; Sack, Lawren

2014-12-01

Many species face increasing drought under climate change. Plasticity has been predicted to strongly influence species' drought responses, but broad patterns in plasticity have not been examined for key drought tolerance traits, including turgor loss or 'wilting' point (πtlp ). As soil dries, plants shift πtlp by accumulating solutes (i.e. 'osmotic adjustment'). We conducted the first global analysis of plasticity in Δπtlp and related traits for 283 wild and crop species in ecosystems worldwide. Δπtlp was widely prevalent but moderate (-0.44 MPa), accounting for 16% of post-drought πtlp. Thus, pre-drought πtlp was a considerably stronger predictor of post-drought πtlp across species of wild plants. For cultivars of certain crops Δπtlp accounted for major differences in post-drought πtlp. Climate was correlated with pre- and post-drought πtlp, but not Δπtlp. Thus, despite the wide prevalence of plasticity, πtlp measured in one season can reliably characterise most species' constitutive drought tolerances and distributions relative to water supply. © 2014 John Wiley & Sons Ltd/CNRS.

Global analysis of thermal tolerance and latitude in ectotherms

PubMed Central

Sunday, Jennifer M.; Bates, Amanda E.; Dulvy, Nicholas K.

2011-01-01

A tenet of macroecology is that physiological processes of organisms are linked to large-scale geographical patterns in environmental conditions. Species at higher latitudes experience greater seasonal temperature variation and are consequently predicted to withstand greater temperature extremes. We tested for relationships between breadths of thermal tolerance in ectothermic animals and the latitude of specimen location using all available data, while accounting for habitat, hemisphere, methodological differences and taxonomic affinity. We found that thermal tolerance breadths generally increase with latitude, and do so at a greater rate in the Northern Hemisphere. In terrestrial ectotherms, upper thermal limits vary little while lower thermal limits decrease with latitude. By contrast, marine species display a coherent poleward decrease in both upper and lower thermal limits. Our findings provide comprehensive global support for hypotheses generated from studies at smaller taxonomic subsets and geographical scales. Our results further indicate differences between terrestrial and marine ectotherms in how thermal physiology varies with latitude that may relate to the degree of temperature variability experienced on land and in the ocean. PMID:21106582

Heat Shock Proteins in Association with Heat Tolerance in Grasses

PubMed Central

Xu, Yan; Zhan, Chenyang; Huang, Bingru

2011-01-01

The grass family Poaceae includes annual species cultivated as major grain crops and perennial species cultivated as forage or turf grasses. Heat stress is a primary factor limiting growth and productivity of cool-season grass species and is becoming a more significant problem in the context of global warming. Plants have developed various mechanisms in heat-stress adaptation, including changes in protein metabolism such as the induction of heat shock proteins (HSPs). This paper summarizes the structure and function of major HSPs, recent research progress on the association of HSPs with grass tolerance to heat stress, and incorporation of HSPs in heat-tolerant grass breeding. PMID:22084689

Developing and testing a global-scale regression model to quantify mean annual streamflow

NASA Astrophysics Data System (ADS)

Barbarossa, Valerio; Huijbregts, Mark A. J.; Hendriks, A. Jan; Beusen, Arthur H. W.; Clavreul, Julie; King, Henry; Schipper, Aafke M.

2017-01-01

Quantifying mean annual flow of rivers (MAF) at ungauged sites is essential for assessments of global water supply, ecosystem integrity and water footprints. MAF can be quantified with spatially explicit process-based models, which might be overly time-consuming and data-intensive for this purpose, or with empirical regression models that predict MAF based on climate and catchment characteristics. Yet, regression models have mostly been developed at a regional scale and the extent to which they can be extrapolated to other regions is not known. In this study, we developed a global-scale regression model for MAF based on a dataset unprecedented in size, using observations of discharge and catchment characteristics from 1885 catchments worldwide, measuring between 2 and 106 km2. In addition, we compared the performance of the regression model with the predictive ability of the spatially explicit global hydrological model PCR-GLOBWB by comparing results from both models to independent measurements. We obtained a regression model explaining 89% of the variance in MAF based on catchment area and catchment averaged mean annual precipitation and air temperature, slope and elevation. The regression model performed better than PCR-GLOBWB for the prediction of MAF, as root-mean-square error (RMSE) values were lower (0.29-0.38 compared to 0.49-0.57) and the modified index of agreement (d) was higher (0.80-0.83 compared to 0.72-0.75). Our regression model can be applied globally to estimate MAF at any point of the river network, thus providing a feasible alternative to spatially explicit process-based global hydrological models.

Evolvement of Uniformity and Volatility in the Stressed Global Financial Village

PubMed Central

Kenett, Dror Y.; Raddant, Matthias; Lux, Thomas; Ben-Jacob, Eshel

2012-01-01

Background In the current era of strong worldwide market couplings the global financial village became highly prone to systemic collapses, events that can rapidly sweep throughout the entire village. Methodology/Principal Findings We present a new methodology to assess and quantify inter-market relations. The approach is based on the correlations between the market index, the index volatility, the market Index Cohesive Force and the meta-correlations (correlations between the intra-correlations.) We investigated the relations between six important world markets—U.S., U.K., Germany, Japan, China and India—from January 2000 until December 2010. We found that while the developed “western” markets (U.S., U.K., Germany) are highly correlated, the interdependencies between these markets and the developing “eastern” markets (India and China) are volatile and with noticeable maxima at times of global world events. The Japanese market switches “identity”—it switches between periods of high meta-correlations with the “western” markets and periods when it behaves more similarly to the “eastern” markets. Conclusions/Significance The methodological framework presented here provides a way to quantify the evolvement of interdependencies in the global market, evaluate a world financial network and quantify changes in the world inter market relations. Such changes can be used as precursors to the agitation of the global financial village. Hence, the new approach can help to develop a sensitive “financial seismograph” to detect early signs of global financial crises so they can be treated before they develop into worldwide events. PMID:22347444

Satellite assessment of increasing tree cover 1982-2016

NASA Astrophysics Data System (ADS)

Song, X. P.; Hansen, M.

2017-12-01

The Earth's vegetation has undergone dramatic changes as we enter the Anthropocene. Recent studies have quantified global forest cover dynamics and resulting biogeochemical and biophysical impacts to the climate for the post-2000 time period. However, long-term gradual changes in undisturbed forests are less well quantified. We mapped annual tree cover using satellite data and quantified tree cover change during 1982-2016. The dataset was produced by combining optical observations from multiple satellite sensors, including the Advanced Very High Resolution Radiometer, the Moderate Resolution Imaging Spectroradiometer, the Landsat Enhanced Thematic Mapper Plus and various very high spatial resolution sensors. Contrary to current understanding of forest area change, global tree cover increased by 7%. The overall net gain in tree cover is a result of net loss in the tropics overweighed by net gain in the subtropical, temperate and boreal zones. All mountain systems, regardless of climate domain, experienced increases in tree cover. Regional patterns of tree cover gain including eastern United States, eastern Europe and southern China, indicate profound influences of socioeconomic, political or land management changes in shaping long-term environmental change. Results provide the first comprehensive record of global tree cover dynamics over the past four decades and may be used to reduce uncertainties in the quantification of the global carbon cycle.

Damage Tolerance and Reliability of Turbine Engine Components

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1999-01-01

This report describes a formal method to quantify structural damage tolerance and reliability in the presence of a multitude of uncertainties in turbine engine components. The method is based at the material behavior level where primitive variables with their respective scatter ranges are used to describe behavior. Computational simulation is then used to propagate the uncertainties to the structural scale where damage tolerance and reliability are usually specified. Several sample cases are described to illustrate the effectiveness, versatility, and maturity of the method. Typical results from this method demonstrate that it is mature and that it can be used to probabilistically evaluate turbine engine structural components. It may be inferred from the results that the method is suitable for probabilistically predicting the remaining life in aging or deteriorating structures, for making strategic projections and plans, and for achieving better, cheaper, faster products that give competitive advantages in world markets.

On flaw tolerance of nacre: a theoretical study

PubMed Central

Shao, Yue; Zhao, Hong-Ping; Feng, Xi-Qiao

2014-01-01

As a natural composite, nacre has an elegant staggered ‘brick-and-mortar’ microstructure consisting of mineral platelets glued by organic macromolecules, which endows the material with superior mechanical properties to achieve its biological functions. In this paper, a microstructure-based crack-bridging model is employed to investigate how the strength of nacre is affected by pre-existing structural defects. Our analysis demonstrates that owing to its special microstructure and the toughening effect of platelets, nacre has a superior flaw-tolerance feature. The maximal crack size that does not evidently reduce the tensile strength of nacre is up to tens of micrometres, about three orders higher than that of pure aragonite. Through dimensional analysis, a non-dimensional parameter is proposed to quantify the flaw-tolerance ability of nacreous materials in a wide range of structural parameters. This study provides us some inspirations for optimal design of advanced biomimetic composites. PMID:24402917

An Air Revitalization Model (ARM) for Regenerative Life Support Systems (RLSS)

NASA Technical Reports Server (NTRS)

Hart, Maxwell M.

1990-01-01

The primary objective of the air revitalization model (ARM) is to determine the minimum buffer capacities that would be necessary for long duration space missions. Several observations are supported by the current configuration sizes: the baseline values for each gas and the day to day or month to month fluctuations that are allowed. The baseline values depend on the minimum safety tolerances and the quantities of life support consumables necessary to survive the worst case scenarios within those tolerances. Most, it not all, of these quantities can easily be determined by ARM once these tolerances are set. The day to day fluctuations also require a command decision. It is already apparent from the current configuration of ARM that the tighter these fluctuations are controlled, the more energy used, the more nonregenerable hydrazine consumed, and the larger the required capacities for the various gas generators. All of these relationships could clearly be quantified by one operational ARM.

Global Climate Change and the Mitigation Challenge

EPA Science Inventory

Book edited by Frank Princiotta titled Global Climate Change--The Technology Challenge Transparent modeling tools and the most recent literature are used, to quantify the challenge posed by climate change and potential technological remedies. The chapter examines forces driving ...

Buffered coscheduling for parallel programming and enhanced fault tolerance

DOEpatents

Petrini, Fabrizio [Los Alamos, NM; Feng, Wu-chun [Los Alamos, NM

2006-01-31

A computer implemented method schedules processor jobs on a network of parallel machine processors or distributed system processors. Control information communications generated by each process performed by each processor during a defined time interval is accumulated in buffers, where adjacent time intervals are separated by strobe intervals for a global exchange of control information. A global exchange of the control information communications at the end of each defined time interval is performed during an intervening strobe interval so that each processor is informed by all of the other processors of the number of incoming jobs to be received by each processor in a subsequent time interval. The buffered coscheduling method of this invention also enhances the fault tolerance of a network of parallel machine processors or distributed system processors

Effective tolerance based on resource reallocation is a virus-specific defence in Arabidopsis thaliana.

PubMed

Shukla, Aayushi; Pagán, Israel; García-Arenal, Fernando

2018-06-01

Plant viruses often harm their hosts, which have developed mechanisms to prevent or minimize the effects of virus infection. Resistance and tolerance are the two main plant defences to pathogens. Although resistance to plant viruses has been studied extensively, tolerance has received much less attention. Theory predicts that tolerance to low-virulent parasites would be achieved through resource reallocation from growth to reproduction, whereas tolerance to high-virulent parasites would be attained through shortening of the pre-reproductive period. We have shown previously that the tolerance of Arabidopsis thaliana to Cucumber mosaic virus (CMV), a relatively low-virulent virus in this host, accords to these predictions. However, whether other viruses trigger the same response, and how A. thaliana copes with highly virulent virus infections remains unexplored. To address these questions, we challenged six A. thaliana wild genotypes with five viruses with different genomic structures, life histories and transmission modes. In these plants, we quantified virus multiplication, virulence, and the effects of infection on plant growth and reproduction, and on the developmental schedule. Our results indicate that virus multiplication varies according to the virus × host genotype interaction. Conversely, effective tolerance is observed only on CMV infection, and is associated with resource reallocation from growth to reproduction. Tolerance to the other viruses is observed only in specific host-virus combinations and, at odds with theoretical predictions, is linked to longer pre-reproductive periods. These findings only partially agree with theoretical predictions, and contribute to a better understanding of pathogenic processes in plant-virus interactions. © 2017 BSPP AND JOHN WILEY & SONS LTD.

Salinity induced differential methylation patterns in contrasting cultivars of foxtail millet (Setaria italica L.).

PubMed

Pandey, Garima; Yadav, Chandra Bhan; Sahu, Pranav Pankaj; Muthamilarasan, Mehanathan; Prasad, Manoj

2017-05-01

Genome-wide methylation analysis of foxtail millet cultivars contrastingly differing in salinity tolerance revealed DNA demethylation events occurring in tolerant cultivar under salinity stress, eventually modulating the expression of stress-responsive genes. Reduced productivity and significant yield loss are the adverse effects of environmental conditions on physiological and biochemical pathways in crop plants. In this context, understanding the epigenetic machinery underlying the tolerance traits in a naturally stress tolerant crop is imperative. Foxtail millet (Setaria italica) is known for its better tolerance to abiotic stresses compared to other cereal crops. In the present study, methylation-sensitive amplified polymorphism (MSAP) technique was used to quantify the salt-induced methylation changes in two foxtail millet cultivars contrastingly differing in their tolerance levels to salt stress. The study highlighted that the DNA methylation level was significantly reduced in tolerant cultivar compared to sensitive cultivar. A total of 86 polymorphic MSAP fragments were identified, sequenced and functionally annotated. These fragments showed sequence similarity to several genes including ABC transporter, WRKY transcription factor, serine threonine-protein phosphatase, disease resistance, oxidoreductases, cell wall-related enzymes and retrotransposon and transposase like proteins, suggesting salt stress-induced methylation in these genes. Among these, four genes were chosen for expression profiling which showed differential expression pattern between both cultivars of foxtail millet. Altogether, the study infers that salinity stress induces genome-wide DNA demethylation, which in turn, modulates expression of corresponding genes.

Metabolomic approach for improving ethanol stress tolerance in Saccharomyces cerevisiae.

PubMed

Ohta, Erika; Nakayama, Yasumune; Mukai, Yukio; Bamba, Takeshi; Fukusaki, Eiichiro

2016-04-01

The budding yeast Saccharomyces cerevisiae is widely used for brewing and ethanol production. The ethanol sensitivity of yeast cells is still a serious problem during ethanol fermentation, and a variety of genetic approaches (e.g., random mutant screening under selective pressure of ethanol) have been developed to improve ethanol tolerance. In this study, we developed a strategy for improving ethanol tolerance of yeast cells based on metabolomics as a high-resolution quantitative phenotypic analysis. We performed gas chromatography-mass spectrometry analysis to identify and quantify 36 compounds on 14 mutant strains including knockout strains for transcription factor and metabolic enzyme genes. A strong relation between metabolome of these mutants and their ethanol tolerance was observed. Data mining of the metabolomic analysis showed that several compounds (such as trehalose, valine, inositol and proline) contributed highly to ethanol tolerance. Our approach successfully detected well-known ethanol stress related metabolites such as trehalose and proline thus, to further prove our strategy, we focused on valine and inositol as the most promising target metabolites in our study. Our results show that simultaneous deletion of LEU4 and LEU9 (leading to accumulation of valine) or INM1 and INM2 (leading to reduction of inositol) significantly enhanced ethanol tolerance. This study shows the potential of the metabolomic approach to identify target genes for strain improvement of S. cerevisiae with higher ethanol tolerance. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Understanding abiotic stress tolerance mechanisms in soybean: a comparative evaluation of soybean response to drought and flooding stress.

PubMed

Mutava, Raymond N; Prince, Silvas Jebakumar K; Syed, Naeem Hasan; Song, Li; Valliyodan, Babu; Chen, Wei; Nguyen, Henry T

2015-01-01

Many sources of drought and flooding tolerance have been identified in soybean, however underlying molecular and physiological mechanisms are poorly understood. Therefore, it is important to illuminate different plant responses to these abiotic stresses and understand the mechanisms that confer tolerance. Towards this goal we used four contrasting soybean (Glycine max) genotypes (PI 567690--drought tolerant, Pana--drought susceptible, PI 408105A--flooding tolerant, S99-2281--flooding susceptible) grown under greenhouse conditions and compared genotypic responses to drought and flooding at the physiological, biochemical, and cellular level. We also quantified these variations and tried to infer their role in drought and flooding tolerance in soybean. Our results revealed that different mechanisms contribute to reduction in net photosynthesis under drought and flooding stress. Under drought stress, ABA and stomatal conductance are responsible for reduced photosynthetic rate; while under flooding stress, accumulation of starch granules played a major role. Drought tolerant genotypes PI 567690 and PI 408105A had higher plastoglobule numbers than the susceptible Pana and S99-2281. Drought stress increased the number and size of plastoglobules in most of the genotypes pointing to a possible role in stress tolerance. Interestingly, there were seven fibrillin proteins localized within the plastoglobules that were up-regulated in the drought and flooding tolerant genotypes PI 567690 and PI 408105A, respectively, but down-regulated in the drought susceptible genotype Pana. These results suggest a potential role of Fibrillin proteins, FBN1a, 1b and 7a in soybean response to drought and flooding stress. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Open Source Tools for Assessment of Global Water Availability, Demands, and Scarcity

NASA Astrophysics Data System (ADS)

Li, X.; Vernon, C. R.; Hejazi, M. I.; Link, R. P.; Liu, Y.; Feng, L.; Huang, Z.; Liu, L.

2017-12-01

Water availability and water demands are essential factors for estimating water scarcity conditions. To reproduce historical observations and to quantify future changes in water availability and water demand, two open source tools have been developed by the JGCRI (Joint Global Change Research Institute): Xanthos and GCAM-STWD. Xanthos is a gridded global hydrologic model, designed to quantify and analyze water availability in 235 river basins. Xanthos uses a runoff generation and a river routing modules to simulate both historical and future estimates of total runoff and streamflows on a monthly time step at a spatial resolution of 0.5 degrees. GCAM-STWD is a spatiotemporal water disaggregation model used with the Global Change Assessment Model (GCAM) to spatially downscale global water demands for six major enduse sectors (irrigation, domestic, electricity generation, mining, and manufacturing) from the region scale to the scale of 0.5 degrees. GCAM-STWD then temporally downscales the gridded annual global water demands to monthly results. These two tools, written in Python, can be integrated to assess global, regional or basin-scale water scarcity or water stress. Both of the tools are extensible to ensure flexibility and promote contribution from researchers that utilize GCAM and study global water use and supply.

Contributions of groundwater pumping to global sea level rise: Continental-scale and interannual analysis

NASA Astrophysics Data System (ADS)

Yeh, P. J. F.; Chen, Y.; Lo, M. H.; Wada, Y.; Famiglietti, J. S.; Reager, J. T., II; Zhang, C.; Wu, R. J.

2017-12-01

Groundwater depletion (GWD) is an anthropogenic driver of changes in terrestrial water storage (TWS). Despite small in magnitudes comparing to most terrestrial hydrologic fluxes, it has important long-term contributions to global sea level rise (SLR). Past studies on the evaluation of the contributions from GWD to SLR were generally limited to a global-scale context and a long-term average perspective. This study examines the impacts of GWD on both terrestrial and atmospheric water balances and quantify the respective contribution to global sea level rise (SLR) using a global climate modelling approach. The annual contributions to global SLR from each continent during the modelling period 1900-1999 are quantified and compared. The contribution from each continent can be decomposed into a direct effect via the change in continental river discharges (R) and an indirect effect via the change in atmosphere water vapour convergence from ocean to land (C). An increase in R and a reduction in C would contribute positively to global SLR. The contribution due to GWD to SLR is compared with the contribution due to natural variability of TWS. Through this study, different dynamics and mechanisms responsible for the GWD contribution to SLR in different continents and time horizons can be identified for better understanding this globally significant environmental issue under warming climate.

Satellite Studies of Cirrus Clouds for Project Fire

NASA Technical Reports Server (NTRS)

1997-01-01

Examine global cloud climatologies for evidence of human caused changes in cloud cover and their effect on the Earth's heat budget through radiative processes. Quantify climatological changes in global cloud cover and estimate their effect on the Earth's heat budget. Improve our knowledge of global cloud cover and its changes through the merging of several satellite data sets.

A comparative framework for maneuverability and gust tolerance of aerial microsystems

NASA Astrophysics Data System (ADS)

Campbell, Renee

Aerial microsystems have the potential of navigating low-altitude, cluttered environments such as urban corridors and building interiors. Reliable systems require both agility and tolerance to gusts. While many platform designs are under development, no framework currently exists to quantitatively assess these inherent bare airframe characteristics which are independent of closed loop controllers. This research develops a method to quantify the maneuverability and gust tolerance of vehicles using reachability and disturbance sensitivity sets. The method is applied to a stable flybar helicopter and an unstable flybarless helicopter, whose state space models were formed through system identification. Model-based static H∞ controllers were also implemented on the vehicles and tested in the lab using fan-generated gusts. It is shown that the flybar restricts the bare airframe's ability to maneuver in translational velocity directions. As such, the flybarless helicopter proved more maneuverable and gust tolerant than the flybar helicopter. This approach was specifically applied here to compare stable and unstable helicopter platforms; however, the framework may be used to assess a broad range of aerial microsystems.

Nature of the chemical bond and prediction of radiation tolerance in pyrochlore and defect fluorite compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lumpkin, Gregory R.; Institute of Materials and Engineering Science, Australian Nuclear Science and Technology Organisation, Private Mail Bag 1, Menai, NSW 2234; Pruneda, Miguel

2007-04-15

The radiation tolerance of synthetic pyrochlore and defect fluorite compounds has been studied using ion irradiation. We show that the results can be quantified in terms of the critical temperature for amorphization, structural parameters, classical Pauling electronegativity difference, and disorder energies. Our results demonstrate that radiation tolerance is correlated with a change in the structure from pyrochlore to defect fluorite, a smaller unit cell dimension, and lower cation-anion disorder energy. Radiation tolerance is promoted by an increase in the Pauling cation-anion electronegativity difference or, in other words, an increase in the ionicity of the chemical bonds. A further analysis ofmore » the data indicates that, of the two possible cation sites in ideal pyrochlore, the smaller B-site cation appears to play the major role in bonding. This result is supported by ab initio calculations of the structure and bonding, showing a correlation between the Mulliken overlap populations of the B-site cation and the critical temperature. - Graphical abstract: Three-dimensional representation of the predicted critical amorphization temperature in pyrochlores.« less

Axelrod Model of Social Influence with Cultural Hybridization

NASA Astrophysics Data System (ADS)

Radillo-Díaz, Alejandro; Pérez, Luis A.; Del Castillo-Mussot, Marcelo

2012-10-01

Since cultural interactions between a pair of social agents involve changes in both individuals, we present simulations of a new model based on Axelrod's homogenization mechanism that includes hybridization or mixture of the agents' features. In this new hybridization model, once a cultural feature of a pair of agents has been chosen for the interaction, the average of the values for this feature is reassigned as the new value for both agents after interaction. Moreover, a parameter representing social tolerance is implemented in order to quantify whether agents are similar enough to engage in interaction, as well as to determine whether they belong to the same cluster of similar agents after the system has reached the frozen state. The transitions from a homogeneous state to a fragmented one decrease in abruptness as tolerance is increased. Additionally, the entropy associated to the system presents a maximum within the transition, the width of which increases as tolerance does. Moreover, a plateau was found inside the transition for a low-tolerance system of agents with only two cultural features.

Master of all trades: thermal acclimation and adaptation of cardiac function in a broadly distributed marine invasive species, the European green crab, Carcinus maenas.

PubMed

Tepolt, Carolyn K; Somero, George N

2014-04-01

As global warming accelerates, there is increasing concern about how ecosystems may change as a result of species loss and replacement. Here, we examined the thermal physiology of the European green crab (Carcinus maenas Linnaeus 1758), a globally invasive species, along three parallel thermal gradients in its native and invasive ranges. At each site, we assessed cardiac physiology to determine heat and cold tolerance and acclimatory plasticity. We found that, overall, the species is highly tolerant of both heat and cold, and that it survives higher temperatures than co-occurring native marine crustaceans. Further, we found that both heat and cold tolerance are plastic in response to short-term acclimation (18-31 days at either 5 or 25°C). Comparing patterns within ranges, we found latitudinal gradients in thermal tolerance in the native European range and in the invasive range in eastern North America. This pattern is strongest in the native range, and likely evolved there. Because of a complicated invasion history, the latitudinal pattern in the eastern North American invasive range may be due either to rapid adaptation post-invasion or to adaptive differences between the ancestral populations that founded the invasion. Overall, the broad thermal tolerance ranges of green crabs, which may facilitate invasion of novel habitats, derive from high inherent eurythermality and acclimatory plasticity and potentially adaptive differentiation among populations. The highly flexible physiology that results from these capacities may represent the hallmark of a successful invasive species, and may provide a model for success in a changing world.

Transcriptomic study to understand thermal adaptation in a high temperature-tolerant strain of Pyropia haitanensis

PubMed Central

Wang, Wenlei; Teng, Fei; Lin, Yinghui; Ji, Dehua; Xu, Yan; Chen, Changsheng

2018-01-01

Pyropia haitanensis, a high-yield commercial seaweed in China, is currently undergoing increasing levels of high-temperature stress due to gradual global warming. The mechanisms of plant responses to high temperature stress vary with not only plant type but also the degree and duration of high temperature. To understand the mechanism underlying thermal tolerance in P. haitanensis, gene expression and regulation in response to short- and long-term temperature stresses (SHS and LHS) was investigated by performing genome-wide high-throughput transcriptomic sequencing for a high temperature tolerant strain (HTT). A total of 14,164 differential expression genes were identified to be high temperature-responsive in at least one time point by high-temperature treatment, representing 41.10% of the total number of unigenes. The present data indicated a decrease in the photosynthetic and energy metabolic rates in HTT to reduce unnecessary energy consumption, which in turn facilitated in the rapid establishment of acclimatory homeostasis in its transcriptome during SHS. On the other hand, an increase in energy consumption and antioxidant substance activity was observed with LHS, which apparently facilitates in the development of resistance against severe oxidative stress. Meanwhile, ubiquitin-mediated proteolysis, brassinosteroids, and heat shock proteins also play a vital role in HTT. The effects of SHS and LHS on the mechanism of HTT to resist heat stress were relatively different. The findings may facilitate further studies on gene discovery and the molecular mechanisms underlying high-temperature tolerance in P. haitanensis, as well as allow improvement of breeding schemes for high temperature-tolerant macroalgae that can resist global warming. PMID:29694388

Transcriptomic study to understand thermal adaptation in a high temperature-tolerant strain of Pyropia haitanensis.

PubMed

Wang, Wenlei; Teng, Fei; Lin, Yinghui; Ji, Dehua; Xu, Yan; Chen, Changsheng; Xie, Chaotian

2018-01-01

Pyropia haitanensis, a high-yield commercial seaweed in China, is currently undergoing increasing levels of high-temperature stress due to gradual global warming. The mechanisms of plant responses to high temperature stress vary with not only plant type but also the degree and duration of high temperature. To understand the mechanism underlying thermal tolerance in P. haitanensis, gene expression and regulation in response to short- and long-term temperature stresses (SHS and LHS) was investigated by performing genome-wide high-throughput transcriptomic sequencing for a high temperature tolerant strain (HTT). A total of 14,164 differential expression genes were identified to be high temperature-responsive in at least one time point by high-temperature treatment, representing 41.10% of the total number of unigenes. The present data indicated a decrease in the photosynthetic and energy metabolic rates in HTT to reduce unnecessary energy consumption, which in turn facilitated in the rapid establishment of acclimatory homeostasis in its transcriptome during SHS. On the other hand, an increase in energy consumption and antioxidant substance activity was observed with LHS, which apparently facilitates in the development of resistance against severe oxidative stress. Meanwhile, ubiquitin-mediated proteolysis, brassinosteroids, and heat shock proteins also play a vital role in HTT. The effects of SHS and LHS on the mechanism of HTT to resist heat stress were relatively different. The findings may facilitate further studies on gene discovery and the molecular mechanisms underlying high-temperature tolerance in P. haitanensis, as well as allow improvement of breeding schemes for high temperature-tolerant macroalgae that can resist global warming.

Probabilistic attribution of individual unprecedented extreme events

NASA Astrophysics Data System (ADS)

Diffenbaugh, N. S.

2016-12-01

The last decade has seen a rapid increase in efforts to understand the influence of global warming on individual extreme climate events. Although trends in the distributions of climate observations have been thoroughly analyzed, rigorously quantifying the contribution of global-scale warming to individual events that are unprecedented in the observed record presents a particular challenge. This paper describes a method for leveraging observations and climate model ensembles to quantify the influence of historical global warming on the severity and probability of unprecedented events. This approach uses formal inferential techniques to quantify four metrics: (1) the contribution of the observed trend to the event magnitude, (2) the contribution of the observed trend to the event probability, (3) the probability of the observed trend in the current climate and a climate without human influence, and (4) the probability of the event magnitude in the current climate and a climate without human influence. Illustrative examples are presented, spanning a range of climate variables, timescales, and regions. These examples illustrate that global warming can influence the severity and probability of unprecedented extremes. In some cases - particularly high temperatures - this change is indicated by changes in the mean. However, changes in probability do not always arise from changes in the mean, suggesting that global warming can alter the frequency with which complex physical conditions co-occur. Because our framework is transparent and highly generalized, it can be readily applied to a range of climate events, regions, and levels of climate forcing.

Will the Antarctic tardigrade Acutuncus antarcticus be able to withstand environmental stresses related to global climate change?

PubMed

Giovannini, Ilaria; Altiero, Tiziana; Guidetti, Roberto; Rebecchi, Lorena

2018-02-20

Because conditions in continental Antarctica are highly selective and extremely hostile to life, its biota is depauperate, but well adapted to live in this region. Global climate change has the potential to impact continental Antarctic organisms because of increasing temperatures and ultraviolet radiation. This research evaluates how ongoing climate changes will affect Antarctic species, and whether Antarctic organisms will be able to adapt to the new environmental conditions. Tardigrades represent one of the main terrestrial components of Antarctic meiofauna; therefore, the pan-Antarctic tardigrade Acutuncus antarcticus was used as model to predict the fate of Antarctic meiofauna threatened by climate change. Acutuncus antarcticus individuals tolerate events of desiccation, increased temperature and UV radiation. Both hydrated and desiccated animals tolerate increases in UV radiation, even though the desiccated animals are more resistant. Nevertheless, the survivorship of hydrated and desiccated animals is negatively affected by the combination of temperature and UV radiation, with the hydrated animals being more tolerant than desiccated animals. Finally, UV radiation has a negative impact on the life history traits of successive generations of A. antarcticus , causing an increase in egg reabsorption and teratological events. In the long run, A. antarcticus could be at risk of population reductions or even extinction. Nevertheless, because the changes in global climate will proceed gradually and an overlapping of temperature and UV increase could be limited in time, A. antarcticus , as well as many other Antarctic organisms, could have the potential to overcome global warming stresses, and/or the time and capability to adapt to the new environmental conditions. © 2018. Published by The Company of Biologists Ltd.

Global gene expression analysis using RNA-seq uncovered a new role for SR1/CAMTA3 transcription factor in salt stress

PubMed Central

Prasad, Kasavajhala V. S. K.; Abdel-Hameed, Amira A. E.; Xing, Denghui; Reddy, Anireddy S. N.

2016-01-01

Abiotic and biotic stresses cause significant yield losses in all crops. Acquisition of stress tolerance in plants requires rapid reprogramming of gene expression. SR1/CAMTA3, a member of signal responsive transcription factors (TFs), functions both as a positive and a negative regulator of biotic stress responses and as a positive regulator of cold stress-induced gene expression. Using high throughput RNA-seq, we identified ~3000 SR1-regulated genes. Promoters of about 60% of the differentially expressed genes have a known DNA binding site for SR1, suggesting that they are likely direct targets. Gene ontology analysis of SR1-regulated genes confirmed previously known functions of SR1 and uncovered a potential role for this TF in salt stress. Our results showed that SR1 mutant is more tolerant to salt stress than the wild type and complemented line. Improved tolerance of sr1 seedlings to salt is accompanied with the induction of salt-responsive genes. Furthermore, ChIP-PCR results showed that SR1 binds to promoters of several salt-responsive genes. These results suggest that SR1 acts as a negative regulator of salt tolerance by directly repressing the expression of salt-responsive genes. Overall, this study identified SR1-regulated genes globally and uncovered a previously uncharacterized role for SR1 in salt stress response. PMID:27251464

Quantifying salinity-induced changes on estuarine benthic fauna: The potential implications of climate change

NASA Astrophysics Data System (ADS)

Little, S.; Wood, P. J.; Elliott, M.

2017-11-01

Coastal and estuarine systems worldwide are under threat from global climate change, with potential consequences including an increase in salinities and incursion of saltwater into areas currently subject to tidal and non-tidal freshwater regimes. It is commonly assumed that climate-driven increases in estuarine salinities and saline incursion will be directly reflected in an upstream shift in species distributions and patterns of community composition based on salinity tolerance. This study examined the responses of benthos to medium-term salinity changes in two macrotidal river-estuary systems in SE England to test whether these responses may be representative of climate-induced salinity changes over the long-term. The study reinforced the effect of salinity, related to tidal incursion, as the primary environmental driver of benthic species distribution and community composition. Salinity, however, acted within a hierarchy of factors followed by substratum type, with biotic competition and predator-prey relationships superimposed on these. The assumption that increasing salinities will be directly reflected in a shift in species distributions and patterns of community composition upstream over the long-term was shown to be over simplistic and not representative of a complex and highly variable system. Relative Sea Level Rise (RSLR) projections were predicted to increase estuarine salinities and saline incursion in the study estuaries, which together with projected reductions in river flow will have important consequences for estuarine structure and function, particularly in tidal limnetic zones, despite estuarine communities being pre-adapted to cope with fluctuating salinities. The study identified, however, that limnic-derived fauna inhabiting these zones may demonstrate greater tolerance to salinity change than is currently recognised, and may persist where salinity increases are gradual and zones unbounded.

Interocular suppression in children with deprivation amblyopia.

PubMed

Hamm, Lisa; Chen, Zidong; Li, Jinrong; Black, Joanna; Dai, Shuan; Yuan, Junpeng; Yu, Minbin; Thompson, Benjamin

2017-04-01

In patients with anisometropic or strabismic amblyopia, interocular suppression can be minimized by presenting high contrast stimulus elements to the amblyopic eye and lower contrast elements to the fellow eye. This suggests a structurally intact binocular visual system that is functionally suppressed. We investigated whether suppression can also be overcome by contrast balancing in children with deprivation amblyopia due to childhood cataracts. To quantify interocular contrast balance, contrast interference thresholds were measured using an established dichoptic global motion technique for 21 children with deprivation amblyopia, 14 with anisometropic or mixed strabismic/anisometropic amblyopia and 10 visually normal children (mean age mean=9.9years, range 5-16years). We found that interocular suppression could be overcome by contrast balancing in most children with deprivation amblyopia, at least intermittently, and all children with anisometropic or mixed anisometropic/strabismic amblyopia. However, children with deprivation amblyopia due to early unilateral or bilateral cataracts could tolerate only very low contrast levels to the stronger eye indicating strong suppression. Our results suggest that treatment options reliant on contrast balanced dichoptic presentation could be attempted in a subset of children with deprivation amblyopia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Review of recent transgenic studies on abiotic stress tolerance and future molecular breeding in potato.

PubMed

Kikuchi, Akira; Huynh, Huu Duc; Endo, Tsukasa; Watanabe, Kazuo

2015-03-01

Global warming has become a major issue within the last decade. Traditional breeding programs for potato have focused on increasing productivity and quality and disease resistance, thus, modern cultivars have limited tolerance of abiotic stresses. The introgression of abiotic stress tolerance into modern cultivars is essential work for the future. Recently, many studies have investigated abiotic stress using transgenic techniques. This manuscript focuses on the study of abiotic stress, in particular drought, salinity and low temperature, during this century. Dividing studies into these three stress categories for this review was difficult. Thus, based on the study title and the transgene property, transgenic studies were classified into five categories in this review; oxidative scavengers, transcriptional factors, and above three abiotic categories. The review focuses on studies that investigate confer of stress tolerance and the identification of responsible factors, including wild relatives. From a practical application perspective, further evaluation of transgenic potato with abiotic stress tolerance is required. Although potato plants, including wild species, have a large potential for abiotic stress tolerance, exploration of the factors responsible for conferring this tolerance is still developing. Molecular breeding, including genetic engineering and conventional breeding using DNA markers, is expected to develop in the future.

Quantifying the Causes of Differences in Tropospheric OH Within Global Models

NASA Technical Reports Server (NTRS)

Nicely, Julie M.; Salawitch, Ross J.; Canty, Timothy; Anderson, Daniel C.; Arnold, Steve R.; Chipperfield, Martyn P.; Emmons, Louisa K.; Flemming, Johannes; Huijnen, Vincent; Kinnison, Douglas E.;

Drought response in wheat: key genes and regulatory mechanisms controlling root system architecture and transpiration efficiency

NASA Astrophysics Data System (ADS)

Kulkarni, Manoj; Soolanayakanahally, Raju; Ogawa, Satoshi; Uga, Yusaku; Selvaraj, Michael G.; Kagale, Sateesh

2017-12-01

Abiotic stresses such as drought, heat, salinity and flooding threaten global food security. Crop genetic improvement with increased resilience to abiotic stresses is a critical component of crop breeding strategies. Wheat is an important cereal crop and a staple food source globally. Enhanced drought tolerance in wheat is critical for sustainable food production and global food security. Recent advances in drought tolerance research have uncovered many key genes and transcription regulators governing morpho-physiological traits. Genes controlling root architecture and stomatal development play an important role in soil moisture extraction and its retention, and therefore have been targets of molecular breeding strategies for improving drought tolerance. In this systematic review, we have summarized evidence of beneficial contributions of root and stomatal traits to plant adaptation to drought stress. Specifically, we discuss a few key genes such as DRO1 in rice and ERECTA in Arabidopsis and rice that were identified to be the enhancers of drought tolerance via regulation of root traits and transpiration efficiency. Additionally, we highlight several transcription factor families, such as ERF (ethylene response factors), DREB (dehydration responsive element binding), ZFP (zinc finger proteins), WRKY and MYB that were identified to be both positive and negative regulators of drought responses in wheat, rice, maize and/or Arabidopsis. The overall aim of this review was to provide an overview of candidate genes that have been tested as regulators of drought response in plants. The lack of a reference genome sequence for wheat and nontransgenic approaches for manipulation of gene functions in the past had impeded high-resolution interrogation of functional elements, including genes and QTLs, and their application in cultivar improvement. The recent developments in wheat genomics and reverse genetics, including the availability of a gold-standard reference genome sequence and advent genome editing technologies, are expected to aid in deciphering of the functional roles of genes and regulatory networks underlying adaptive phenological traits, and utilizing the outcomes of such studies in developing drought tolerance cultivars.

Drought Response in Wheat: Key Genes and Regulatory Mechanisms Controlling Root System Architecture and Transpiration Efficiency.

PubMed

Kulkarni, Manoj; Soolanayakanahally, Raju; Ogawa, Satoshi; Uga, Yusaku; Selvaraj, Michael G; Kagale, Sateesh

2017-01-01

Abiotic stresses such as, drought, heat, salinity, and flooding threaten global food security. Crop genetic improvement with increased resilience to abiotic stresses is a critical component of crop breeding strategies. Wheat is an important cereal crop and a staple food source globally. Enhanced drought tolerance in wheat is critical for sustainable food production and global food security. Recent advances in drought tolerance research have uncovered many key genes and transcription regulators governing morpho-physiological traits. Genes controlling root architecture and stomatal development play an important role in soil moisture extraction and its retention, and therefore have been targets of molecular breeding strategies for improving drought tolerance. In this systematic review, we have summarized evidence of beneficial contributions of root and stomatal traits to plant adaptation to drought stress. Specifically, we discuss a few key genes such as, DRO1 in rice and ERECTA in Arabidopsis and rice that were identified to be the enhancers of drought tolerance via regulation of root traits and transpiration efficiency. Additionally, we highlight several transcription factor families, such as, ERF (ethylene response factors), DREB (dehydration responsive element binding), ZFP (zinc finger proteins), WRKY, and MYB that were identified to be both positive and negative regulators of drought responses in wheat, rice, maize, and/or Arabidopsis. The overall aim of this review is to provide an overview of candidate genes that have been identified as regulators of drought response in plants. The lack of a reference genome sequence for wheat and non-transgenic approaches for manipulation of gene functions in wheat in the past had impeded high-resolution interrogation of functional elements, including genes and QTLs, and their application in cultivar improvement. The recent developments in wheat genomics and reverse genetics, including the availability of a gold-standard reference genome sequence and advent of genome editing technologies, are expected to aid in deciphering of the functional roles of genes and regulatory networks underlying adaptive phenological traits, and utilizing the outcomes of such studies in developing drought tolerant cultivars.

Observing System Evaluations Using GODAE Systems

DTIC Science & Technology

2009-09-01

DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release, distribution is unlimite 13. SUPPLEMENTARY NOTES 20091228151 14. ABSTRACT Global ocean...forecast systems, developed under the Global Ocean Data Assimilation Experiment (GODAE), are a powerful means of assessing the impact of different...components of the Global Ocean Observing System (GOOS). Using a range of analysis tools and approaches, GODAE systems are useful for quantifying the

Global assessment of ocean carbon export by combining satellite observations and food-web models

NASA Astrophysics Data System (ADS)

Siegel, D. A.; Buesseler, K. O.; Doney, S. C.; Sailley, S. F.; Behrenfeld, M. J.; Boyd, P. W.

2014-03-01

The export of organic carbon from the surface ocean by sinking particles is an important, yet highly uncertain, component of the global carbon cycle. Here we introduce a mechanistic assessment of the global ocean carbon export using satellite observations, including determinations of net primary production and the slope of the particle size spectrum, to drive a food-web model that estimates the production of sinking zooplankton feces and algal aggregates comprising the sinking particle flux at the base of the euphotic zone. The synthesis of observations and models reveals fundamentally different and ecologically consistent regional-scale patterns in export and export efficiency not found in previous global carbon export assessments. The model reproduces regional-scale particle export field observations and predicts a climatological mean global carbon export from the euphotic zone of 6 Pg C yr-1. Global export estimates show small variation (typically < 10%) to factor of 2 changes in model parameter values. The model is also robust to the choices of the satellite data products used and enables interannual changes to be quantified. The present synthesis of observations and models provides a path for quantifying the ocean's biological pump.

Comparing extraction rates of fossil fuel producers against global climate goals

NASA Astrophysics Data System (ADS)

Rekker, Saphira A. C.; O'Brien, Katherine R.; Humphrey, Jacquelyn E.; Pascale, Andrew C.

2018-06-01

Meeting global and national climate goals requires action and cooperation from a multitude of actors1,2. Current methods to define greenhouse gas emission targets for companies fail to acknowledge the unique influence of fossil fuel producers: combustion of reported fossil fuel reserves has the potential to push global warming above 2 °C by 2050, regardless of other efforts to mitigate climate change3. Here, we introduce a method to compare the extraction rates of individual fossil fuel producers against global climate targets, using two different approaches to quantify a burnable fossil fuel allowance (BFFA). BFFAs are calculated and compared with cumulative extraction since 2010 for the world's ten largest investor-owned companies and ten largest state-owned entities (SOEs), for oil and for gas, which together account for the majority of global oil and gas reserves and production. The results are strongly influenced by how BFFAs are quantified; allocating based on reserves favours SOEs over investor-owned companies, while allocating based on production would require most reduction to come from SOEs. Future research could refine the BFFA to account for equity, cost-effectiveness and emissions intensity.

Thermocouple Calibration and Accuracy in a Materials Testing Laboratory

NASA Technical Reports Server (NTRS)

Lerch, B. A.; Nathal, M. V.; Keller, D. J.

2002-01-01

A consolidation of information has been provided that can be used to define procedures for enhancing and maintaining accuracy in temperature measurements in materials testing laboratories. These studies were restricted to type R and K thermocouples (TCs) tested in air. Thermocouple accuracies, as influenced by calibration methods, thermocouple stability, and manufacturer's tolerances were all quantified in terms of statistical confidence intervals. By calibrating specific TCs the benefits in accuracy can be as great as 6 C or 5X better compared to relying on manufacturer's tolerances. The results emphasize strict reliance on the defined testing protocol and on the need to establish recalibration frequencies in order to maintain these levels of accuracy.

Conservatism of lizard thermal tolerances and body temperatures across evolutionary history and geography.

PubMed

Grigg, Joseph W; Buckley, Lauren B

2013-04-23

Species may exhibit similar thermal tolerances via either common ancestry or environmental filtering and local adaptation, if the species inhabit similar environments. We ask whether upper and lower thermal limits (critical thermal maxima and minima) and body temperatures are more strongly conserved across evolutionary history or geography for lizard populations distributed globally. We find that critical thermal maxima are highly conserved with location accounting for a higher proportion of the variation than phylogeny. Notably, thermal tolerance breadth is conserved across the phylogeny despite critical thermal minima showing little niche conservatism. Body temperatures observed during activity in the field show the greatest degree of conservatism, with phylogeny accounting for most of the variation. This suggests that propensities for thermoregulatory behaviour, which can buffer body temperatures from environmental variation, are similar within lineages. Phylogeny and geography constrain thermal tolerances similarly within continents, but variably within clades. Conservatism of thermal tolerances across lineages suggests that the potential for local adaptation to alleviate the impacts of climate change on lizards may be limited.

T Cells with Low Avidity for a Tissue-Restricted Antigen Routinely Evade Central and Peripheral Tolerance and Cause Autoimmunity

PubMed Central

Zehn, Dietmar; Bevan, Michael J.

2009-01-01

Summary T cells causing autoimmunity must escape tolerance. We observed that CD8+ T cells with high avidity for an antigen expressed in the pancreas, kidney, and thymic medulla were efficiently removed from a polyclonal repertoire by central and peripheral tolerance mechanisms. However, both mechanisms spared low-avidity T cells from elimination. Neither the introduction of activated, self-antigen-specific CD4+ helper T cells nor a global inflammatory stimulus were sufficient to activate the low-avidity CD8+ T cells and did not break tolerance. In contrast, challenge with a recombinant bacterium expressing the self antigen primed the low-avidity T cells, and the animals rapidly developed autoimmune diabetes. We suggest that whereas thymic and peripheral tolerance mechanisms remove cells that can be primed by endogenous amounts of self antigen, they do not guard against tissue destruction by low-avidity effector T cells, which have been primed by higher amounts of self antigen or by crossreactive antigens. PMID:16879996

ATG18 and FAB1 are involved in dehydration stress tolerance in Saccharomyces cerevisiae.

PubMed

López-Martínez, Gema; Margalef-Català, Mar; Salinas, Francisco; Liti, Gianni; Cordero-Otero, Ricardo

2015-01-01

Recently, different dehydration-based technologies have been evaluated for the purpose of cell and tissue preservation. Although some early results have been promising, they have not satisfied the requirements for large-scale applications. The long experience of using quantitative trait loci (QTLs) with the yeast Saccharomyces cerevisiae has proven to be a good model organism for studying the link between complex phenotypes and DNA variations. Here, we use QTL analysis as a tool for identifying the specific yeast traits involved in dehydration stress tolerance. Three hybrids obtained from stable haploids and sequenced in the Saccharomyces Genome Resequencing Project showed intermediate dehydration tolerance in most cases. The dehydration resistance trait of 96 segregants from each hybrid was quantified. A smooth, continuous distribution of the anhydrobiosis tolerance trait was found, suggesting that this trait is determined by multiple QTLs. Therefore, we carried out a QTL analysis to identify the determinants of this dehydration tolerance trait at the genomic level. Among the genes identified after reciprocal hemizygosity assays, RSM22, ATG18 and DBR1 had not been referenced in previous studies. We report new phenotypes for these genes using a previously validated test. Finally, our data illustrates the power of this approach in the investigation of the complex cell dehydration phenotype.

Genetic variation in heat-stress tolerance among South American Drosophila populations.

PubMed

Fallis, Lindsey C; Fanara, Juan Jose; Morgan, Theodore J

2011-10-01

Spatial or temporal differences in environmental variables, such as temperature, are ubiquitous in nature and impose stress on organisms. This is especially true for organisms that are isothermal with the environment, such as insects. Understanding the means by which insects respond to temperature and how they will react to novel changes in environmental temperature is important for understanding the adaptive capacity of populations and to predict future trajectories of evolutionary change. The organismal response to heat has been identified as an important environmental variable for insects that can dramatically influence life history characters and geographic range. In the current study we surveyed the amount of variation in heat tolerance among Drosophila melanogaster populations collected at diverse sites along a latitudinal gradient in Argentina (24°-38°S). This is the first study to quantify heat tolerance in South American populations and our work demonstrates that most of the populations surveyed have abundant within-population phenotypic variation, while still exhibiting significant variation among populations. The one exception was the most heat tolerant population that comes from a climate exhibiting the warmest annual mean temperature. All together our results suggest there is abundant genetic variation for heat-tolerance phenotypes within and among natural populations of Drosophila and this variation has likely been shaped by environmental temperature.

ATG18 and FAB1 Are Involved in Dehydration Stress Tolerance in Saccharomyces cerevisiae

PubMed Central

López-Martínez, Gema; Margalef-Català, Mar; Salinas, Francisco; Liti, Gianni; Cordero-Otero, Ricardo

2015-01-01

Recently, different dehydration-based technologies have been evaluated for the purpose of cell and tissue preservation. Although some early results have been promising, they have not satisfied the requirements for large-scale applications. The long experience of using quantitative trait loci (QTLs) with the yeast Saccharomyces cerevisiae has proven to be a good model organism for studying the link between complex phenotypes and DNA variations. Here, we use QTL analysis as a tool for identifying the specific yeast traits involved in dehydration stress tolerance. Three hybrids obtained from stable haploids and sequenced in the Saccharomyces Genome Resequencing Project showed intermediate dehydration tolerance in most cases. The dehydration resistance trait of 96 segregants from each hybrid was quantified. A smooth, continuous distribution of the anhydrobiosis tolerance trait was found, suggesting that this trait is determined by multiple QTLs. Therefore, we carried out a QTL analysis to identify the determinants of this dehydration tolerance trait at the genomic level. Among the genes identified after reciprocal hemizygosity assays, RSM22, ATG18 and DBR1 had not been referenced in previous studies. We report new phenotypes for these genes using a previously validated test. Finally, our data illustrates the power of this approach in the investigation of the complex cell dehydration phenotype. PMID:25803831

Limited potential for adaptation to climate change in a broadly distributed marine crustacean.

PubMed

Kelly, Morgan W; Sanford, Eric; Grosberg, Richard K

2012-01-22

The extent to which acclimation and genetic adaptation might buffer natural populations against climate change is largely unknown. Most models predicting biological responses to environmental change assume that species' climatic envelopes are homogeneous both in space and time. Although recent discussions have questioned this assumption, few empirical studies have characterized intraspecific patterns of genetic variation in traits directly related to environmental tolerance limits. We test the extent of such variation in the broadly distributed tidepool copepod Tigriopus californicus using laboratory rearing and selection experiments to quantify thermal tolerance and scope for adaptation in eight populations spanning more than 17° of latitude. Tigriopus californicus exhibit striking local adaptation to temperature, with less than 1 per cent of the total quantitative variance for thermal tolerance partitioned within populations. Moreover, heat-tolerant phenotypes observed in low-latitude populations cannot be achieved in high-latitude populations, either through acclimation or 10 generations of strong selection. Finally, in four populations there was no increase in thermal tolerance between generations 5 and 10 of selection, suggesting that standing variation had already been depleted. Thus, plasticity and adaptation appear to have limited capacity to buffer these isolated populations against further increases in temperature. Our results suggest that models assuming a uniform climatic envelope may greatly underestimate extinction risk in species with strong local adaptation.

Can We Use Regression Modeling to Quantify Mean Annual Streamflow at a Global-Scale?

NASA Astrophysics Data System (ADS)

Barbarossa, V.; Huijbregts, M. A. J.; Hendriks, J. A.; Beusen, A.; Clavreul, J.; King, H.; Schipper, A.

2016-12-01

Quantifying mean annual flow of rivers (MAF) at ungauged sites is essential for a number of applications, including assessments of global water supply, ecosystem integrity and water footprints. MAF can be quantified with spatially explicit process-based models, which might be overly time-consuming and data-intensive for this purpose, or with empirical regression models that predict MAF based on climate and catchment characteristics. Yet, regression models have mostly been developed at a regional scale and the extent to which they can be extrapolated to other regions is not known. In this study, we developed a global-scale regression model for MAF using observations of discharge and catchment characteristics from 1,885 catchments worldwide, ranging from 2 to 106 km2 in size. In addition, we compared the performance of the regression model with the predictive ability of the spatially explicit global hydrological model PCR-GLOBWB [van Beek et al., 2011] by comparing results from both models to independent measurements. We obtained a regression model explaining 89% of the variance in MAF based on catchment area, mean annual precipitation and air temperature, average slope and elevation. The regression model performed better than PCR-GLOBWB for the prediction of MAF, as root-mean-square error values were lower (0.29 - 0.38 compared to 0.49 - 0.57) and the modified index of agreement was higher (0.80 - 0.83 compared to 0.72 - 0.75). Our regression model can be applied globally at any point of the river network, provided that the input parameters are within the range of values employed in the calibration of the model. The performance is reduced for water scarce regions and further research should focus on improving such an aspect for regression-based global hydrological models.

Genetic diversity and classification of Oryza sativa with emphasis on Chinese rice germplasm

PubMed Central

Wang, C-H; Zheng, X-M; Xu, Q; Yuan, X-P; Huang, L; Zhou, H-F; Wei, X-H; Ge, S

2014-01-01

Despite extensive studies on cultivated rice, the genetic structure and subdivision of this crop remain unclear at both global and local scales. Using 84 nuclear simple sequence repeat markers, we genotyped a panel of 153 global rice cultivars covering all previously recognized groups and 826 cultivars representing the diversity of Chinese rice germplasm. On the basis of model-based grouping, neighbour-joining tree and principal coordinate analysis, we confirmed the widely accepted five major groups of rice cultivars (indica, aus, aromatic, temperate japonica and tropical japonica), and demonstrated that rayada rice was unique in genealogy and should be treated as a new (the sixth) major group of rice germplasm. With reference to the global classification of rice cultivars, we identified three major groups (indica, temperate japonica and tropical japonica) in Chinese rice germplasm and showed that Chinese temperate japonica contained higher diversity than that of global samples, whereas Chinese indica and tropical japonica maintained slightly lower diversity than that present in the global samples. Particularly, we observed that all seasonal, drought-tolerant and endosperm types occurred within each of three major groups of Chinese cultivars, which does not support previous claims that seasonal differentiation exists in Indica and drought-tolerant differentiation is present in Japonica. It is most likely that differentiation of cultivar types arose multiple times stemming from artificial selection for adaptation to local environments. PMID:24326293

Biodiversity Hotspots, Climate Change, and Agricultural Development: Global Limits of Adaptation

NASA Astrophysics Data System (ADS)

Schneider, U. A.; Rasche, L.; Schmid, E.; Habel, J. C.

2017-12-01

Terrestrial ecosystems are threatened by climate and land management change. These changes result from complex and heterogeneous interactions of human activities and natural processes. Here, we study the potential change in pristine area in 33 global biodiversity hotspots within this century under four climate projections (representative concentration pathways) and associated population and income developments (shared socio-economic pathways). A coupled modelling framework computes the regional net expansion of crop and pasture lands as result of changes in food production and consumption. We use a biophysical crop simulation model to quantify climate change impacts on agricultural productivity, water, and nutrient emissions for alternative crop management systems in more than 100 thousand agricultural land polygons (homogeneous response units) and for each climate projection. The crop simulation model depicts detailed soil, weather, and management information and operates with a daily time step. We use time series of livestock statistics to link livestock production to feed and pasture requirements. On the food consumption side, we estimate national demand shifts in all countries by processing population and income growth projections through econometrically estimated Engel curves. Finally, we use a global agricultural sector optimization model to quantify the net change in pristine area in all biodiversity hotspots under different adaptation options. These options include full-scale global implementation of i) crop yield maximizing management without additional irrigation, ii) crop yield maximizing management with additional irrigation, iii) food yield maximizing crop mix adjustments, iv) food supply maximizing trade flow adjustments, v) healthy diets, and vi) combinations of the individual options above. Results quantify the regional potentials and limits of major agricultural producer and consumer adaptation options for the preservation of pristine areas in biodiversity hotspots. Results also quantify the conflicts between food and water security, biodiversity protection, and climate change mitigation.

Global rainfall erosivity assessment based on high-temporal resolution rainfall records.

PubMed

Panagos, Panos; Borrelli, Pasquale; Meusburger, Katrin; Yu, Bofu; Klik, Andreas; Jae Lim, Kyoung; Yang, Jae E; Ni, Jinren; Miao, Chiyuan; Chattopadhyay, Nabansu; Sadeghi, Seyed Hamidreza; Hazbavi, Zeinab; Zabihi, Mohsen; Larionov, Gennady A; Krasnov, Sergey F; Gorobets, Andrey V; Levi, Yoav; Erpul, Gunay; Birkel, Christian; Hoyos, Natalia; Naipal, Victoria; Oliveira, Paulo Tarso S; Bonilla, Carlos A; Meddi, Mohamed; Nel, Werner; Al Dashti, Hassan; Boni, Martino; Diodato, Nazzareno; Van Oost, Kristof; Nearing, Mark; Ballabio, Cristiano

2017-06-23

The exposure of the Earth's surface to the energetic input of rainfall is one of the key factors controlling water erosion. While water erosion is identified as the most serious cause of soil degradation globally, global patterns of rainfall erosivity remain poorly quantified and estimates have large uncertainties. This hampers the implementation of effective soil degradation mitigation and restoration strategies. Quantifying rainfall erosivity is challenging as it requires high temporal resolution(<30 min) and high fidelity rainfall recordings. We present the results of an extensive global data collection effort whereby we estimated rainfall erosivity for 3,625 stations covering 63 countries. This first ever Global Rainfall Erosivity Database was used to develop a global erosivity map at 30 arc-seconds(~1 km) based on a Gaussian Process Regression(GPR). Globally, the mean rainfall erosivity was estimated to be 2,190 MJ mm ha -1 h -1 yr -1 , with the highest values in South America and the Caribbean countries, Central east Africa and South east Asia. The lowest values are mainly found in Canada, the Russian Federation, Northern Europe, Northern Africa and the Middle East. The tropical climate zone has the highest mean rainfall erosivity followed by the temperate whereas the lowest mean was estimated in the cold climate zone.

INTEGRATED INS/GPS NAVIGATION FROM A POPULAR PERSPECTIVE

DOT National Transportation Integrated Search

2002-02-13

Inertial navigation, blended with other navigation aids Global Positioning System (GPS) in particular, has gained significance due to enhanced navigation and inertial reference performance and dissimilarity for fault tolerance and anti-jamming. Relat...

Evaluating uncertainty in environmental life-cycle assessment. A case study comparing two insulation options for a Dutch one-family dwelling.

PubMed

Huijbregts, Mark A J; Gilijamse, Wim; Ragas, Ad M J; Reijnders, Lucas

2003-06-01

The evaluation of uncertainty is relatively new in environmental life-cycle assessment (LCA). It provides useful information to assess the reliability of LCA-based decisions and to guide future research toward reducing uncertainty. Most uncertainty studies in LCA quantify only one type of uncertainty, i.e., uncertainty due to input data (parameter uncertainty). However, LCA outcomes can also be uncertain due to normative choices (scenario uncertainty) and the mathematical models involved (model uncertainty). The present paper outlines a new methodology that quantifies parameter, scenario, and model uncertainty simultaneously in environmental life-cycle assessment. The procedure is illustrated in a case study that compares two insulation options for a Dutch one-family dwelling. Parameter uncertainty was quantified by means of Monte Carlo simulation. Scenario and model uncertainty were quantified by resampling different decision scenarios and model formulations, respectively. Although scenario and model uncertainty were not quantified comprehensively, the results indicate that both types of uncertainty influence the case study outcomes. This stresses the importance of quantifying parameter, scenario, and model uncertainty simultaneously. The two insulation options studied were found to have significantly different impact scores for global warming, stratospheric ozone depletion, and eutrophication. The thickest insulation option has the lowest impact on global warming and eutrophication, and the highest impact on stratospheric ozone depletion.

Global and Country-Level Fragility to Major Disruptions in Crop Production

NASA Astrophysics Data System (ADS)

Puma, M. J.; Wada, Y.; Chon, S. Y.; Cook, B. I.; Nordbotten, J. M.

2016-12-01

New food polices are needed to mitigate vulnerabilities in the global food system to unexpected and severe production losses. The starting point for developing such policies is the ability to quantify the potential range of food and economic losses associated with major food-production shocks. Although individual major shock events are unpredictable, it is possible to quantify the relative vulnerabilities of the global food system as a whole and of individual countries within the system to production shocks. Here we combine a scale for food disruptions, which links the magnitude for a production shock with the corresponding short-term food and economic losses for that event (analogous to the well-known Richter magnitude scale for earthquakes), with country-level food system metrics. We demonstrate the value of our approach using the recent El Niño event of 2015-2016. Ultimately, these metrics can be used as part of efforts to develop national and global level food policies to prepare for and mitigate possible food-supply disruptions.

Design of Composite Structures for Reliability and Damage Tolerance

NASA Technical Reports Server (NTRS)

Rais-Rohani, Masoud

1999-01-01

A summary of research conducted during the first year is presented. The research objectives were sought by conducting two tasks: (1) investigation of probabilistic design techniques for reliability-based design of composite sandwich panels, and (2) examination of strain energy density failure criterion in conjunction with response surface methodology for global-local design of damage tolerant helicopter fuselage structures. This report primarily discusses the efforts surrounding the first task and provides a discussion of some preliminary work involving the second task.

Study of Protein Phosphatase 2A (PP2A) Activity in LPS-Induced Tolerance Using Fluorescence-Based and Immunoprecipitation-Aided Methodology.

PubMed

Sun, Lei; Ii, Adlai L Pappy; Pham, Tiffany T; Shanley, Thomas P

2015-06-29

Protein phosphatase 2A (PP2A) is one of the most abundant intracellular serine/threonine (Ser/Thr) phosphatases accounting for 1% of the total cellular protein content. PP2A is comprised of a heterodimeric core enzyme and a substrate-specific regulatory subunit. Potentially, at least seventy different compositions of PP2A exist because of variable regulatory subunit binding that accounts for various activity modulating numerous cell functions. Due to the constitutive phosphatase activity present inside cells, a sensitive assay is required to detect the changes of PP2A activity under various experimental conditions. We optimized a fluorescence assay (DIFMU assay) by combining it with prior anti-PP2A immunoprecipitation to quantify PP2A-specific phosphatase activity. It is also known that prior exposure to lipopolysaccharides (LPS) induces "immune tolerance" of the cells to subsequent stimulation. Herein we report that PP2A activity is upregulated in tolerized peritoneal macrophages, corresponding to decreased TNF-α secretion upon second LPS stimulation. We further examined the role of PP2A in the tolerance effect by using PP2ACαl°xl°x;lyM-Cre conditional knockout macrophages. We found that PP2A phosphatase activity cannot be further increased by tolerance. TNF-α secretion from tolerized PP2ACαl°xl°x;lyM-Cre macrophages is higher than tolerized control macrophages. Furthermore, we showed that the increased TNF-α secretion may be due to an epigenetic transcriptionally active signature on the promoter of TNF-α gene rather than regulation of the NFκB/IκB signaling pathway. These results suggest a role for increased PP2A activity in the regulation of immune tolerance.

Variation in cassava germplasm for tolerance to post-harvest physiological deterioration.

PubMed

Venturini, M T; Santos, L R; Vildoso, C I A; Santos, V S; Oliveira, E J

2016-05-06

Tolerant varieties can effectively control post-harvest physiological deterioration (PPD) of cassava, although knowledge on the genetic variability and inheritance of this trait is needed. The objective of this study was to estimate genetic parameters and identify sources of tolerance to PPD and their stability in cassava accessions. Roots from 418 cassava accessions, grown in four independent experiments, were evaluated for PPD tolerance 0, 2, 5, and 10 days post-harvest. Data were transformed into area under the PPD-progress curve (AUP-PPD) to quantify tolerance. Genetic parameters, stability (Si), adaptability (Ai), and the joint analysis of stability and adaptability (Zi) were obtained via residual maximum likelihood (REML) and best linear unbiased prediction (BLUP) methods. Variance in the genotype (G) x environment (E) interaction and genotypic variance were important for PPD tolerance. Individual broad-sense heritability (hg(2)= 0.38 ± 0.04) and average heritability in accessions (hmg(2)= 0.52) showed high genetic control of PPD tolerance. Genotypic correlation of AUP-PPD in different experiments was of medium magnitude (ȓgA = 0.42), indicating significant G x E interaction. The predicted genotypic values o f G x E free of interaction (û + ĝi) showed high variation. Of the 30 accessions with high Zi, 19 were common to û + ĝi, Si, and Ai parameters. The genetic gain with selection of these 19 cassava accessions was -55.94, -466.86, -397.72, and -444.03% for û + ĝi, Si, Ai, and Zi, respectively, compared with the overall mean for each parameter. These results demonstrate the variability and potential of cassava germplasm to introduce PPD tolerance in commercial varieties.

Quantifying and Monetizing Potential Climate Change Policy Impacts on Terrestrial Ecosystem Carbon Storage and Wildfires in the United States

EPA Science Inventory

This paper quantifies and monetizes climate change impacts on carbon stored in terrestrial vegetation and wildfire incidence in the contiguous United States to assess the benefits of alternative mitigation policies. The MC-1 dynamic global vegetation model was used to develop int...

Hydrological modelling in forested systems | Science ...

EPA Pesticide Factsheets

This chapter provides a brief overview of forest hydrology modelling approaches for answering important global research and management questions. Many hundreds of hydrological models have been applied globally across multiple decades to represent and predict forest hydrological processes. The focus of this chapter is on process-based models and approaches, specifically 'forest hydrology models'; that is, physically based simulation tools that quantify compartments of the forest hydrological cycle. Physically based models can be considered those that describe the conservation of mass, momentum and/or energy. The purpose of this chapter is to provide a brief overview of forest hydrology modeling approaches for answering important global research and management questions. The focus of this chapter is on process-based models and approaches, specifically “forest hydrology models”, i.e., physically-based simulation tools that quantify compartments of the forest hydrological cycle.

Linking transcriptional responses to organismal tolerance reveals mechanisms of thermal sensitivity in a mesothermal endangered fish.

PubMed

Komoroske, Lisa M; Connon, Richard E; Jeffries, Ken M; Fangue, Nann A

2015-10-01

Forecasting species' responses to climate change requires understanding the underlying mechanisms governing environmental stress tolerance, including acclimation capacity and acute stress responses. Current knowledge of these physiological processes in aquatic ectotherms is largely drawn from eurythermal or extreme stenothermal species. Yet many species of conservation concern exhibit tolerance windows and acclimation capacities in between these extremes. We linked transcriptome profiles to organismal tolerance in a mesothermal endangered fish, the delta smelt (Hypomesus transpacificus), to quantify the cellular processes, sublethal thresholds and effects of thermal acclimation on acute stress responses. Delta smelt initiated rapid molecular changes in line with expectations of theoretical thermal limitation models, but also exhibited diminished capacity to modify the expression of some genes and cellular mechanisms key to coping with acute thermal stress found in eurytherms. Sublethal critical thresholds occurred 4-6 °C below their upper tolerance limits, and thermal acclimation shifted the onset of acute thermal stress and tolerance as predicted. However, we found evidence that delta smelt's limited thermal plasticity may be partially due to an inability of individuals to effectively make physiological adjustments to truly achieve new homoeostasis under heightened temperatures, resulting in chronic thermal stress. These findings provide insight into the physiological basis of the diverse patterns of thermal tolerances observed in nature. Moreover, understanding how underlying molecular mechanisms shape thermal acclimation capacity, acute stress responses and ultimately differential phenotypes contributes to a predictive framework to deduce species' responses in situ to changes in selective pressures due to climate change. © 2015 John Wiley & Sons Ltd.

Heat Tolerance Induction of the Indian Meal Moth (Lepidoptera: Pyralidae) Is Accompanied by Upregulation of Heat Shock Proteins and Polyols.

PubMed

Kim, Minhyun; Lee, Seunghee; Chun, Yong Shik; Na, Jahyun; Kwon, Hyeok; Kim, Wook; Kim, Yonggyun

2017-08-01

The Indian meal moth, Plodia interpunctella, causes massive damage to stored grains and processed foods. Heat treatment has been widely used to control insect pests infesting stored grains. However, heat treatment may result in unsatisfactory control owing to heat tolerance of target insects. This study quantified the heat tolerance and analyzed its induction in P. interpunctella. Susceptibility of P. interpunctella to different high temperatures was assessed in all developmental stages. Heat treatment at 44 °C for 1 h caused significant mortalities to all developmental stages, with late-instar larvae exhibiting the highest tolerance. However, the survivorship to heat treatment was significantly increased by pre-exposure to 37 °C for 30 min. The induction of heat tolerance was accompanied by upregulation of two heat shock proteins of Hsc70 and Hsp90. Trehalose and glycerol concentrations in the hemolymph also increased after pre-exposure to 37 °C for 30 min. RNA interference (RNAi) by specific double-stranded RNAs effectively suppressed the inducible expressions of both Hsc70 and Hsp90 in response to 37 °C for 30 min. Either RNAi of Hsc70 or Hsp90 significantly impaired the heat tolerance induction of P. interpunctella. These results suggest that the induction of heat tolerance in P. interpunctella involves the upregulation of these heat shock proteins and hemolymph polyol levels. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Opinion formation on multiplex scale-free networks

NASA Astrophysics Data System (ADS)

Nguyen, Vu Xuan; Xiao, Gaoxi; Xu, Xin-Jian; Li, Guoqi; Wang, Zhen

2018-01-01

Most individuals, if not all, live in various social networks. The formation of opinion systems is an outcome of social interactions and information propagation occurring in such networks. We study the opinion formation with a new rule of pairwise interactions in the novel version of the well-known Deffuant model on multiplex networks composed of two layers, each of which is a scale-free network. It is found that in a duplex network composed of two identical layers, the presence of the multiplexity helps either diminish or enhance opinion diversity depending on the relative magnitudes of tolerance ranges characterizing the degree of openness/tolerance on both layers: there is a steady separation between different regions of tolerance range values on two network layers where multiplexity plays two different roles, respectively. Additionally, the two critical tolerance ranges follow a one-sum rule; that is, each of the layers reaches a complete consensus only if the sum of the tolerance ranges on the two layers is greater than a constant approximately equaling 1, the double of the critical bound on a corresponding isolated network. A further investigation of the coupling between constituent layers quantified by a link overlap parameter reveals that as the layers are loosely coupled, the two opinion systems co-evolve independently, but when the inter-layer coupling is sufficiently strong, a monotonic behavior is observed: an increase in the tolerance range of a layer causes a decline in the opinion diversity on the other layer regardless of the magnitudes of tolerance ranges associated with the layers in question.

Climate and species functional traits influence maximum live tree stocking in the Lake States, USA

Treesearch

Mark J. Ducey; Christopher W. Woodall; Andrés Bravo-Oviedo

2017-01-01

Quantifying the density of live trees in forest stands and partitioning it between species or other stand components is critical for predicting forest dynamics and responses to management, as well as understanding the impacts of stand composition and structure on productivity. As plant traits such as shade tolerance have been proven to refine understanding of plant...

Needle parameter variation of mature black spruce families displaying a genetic x environment interaction in growth

Treesearch

John E. Major; Kurt H. Johnsen; Debby C. Barsi; Moira Campbell

2013-01-01

To examine soil moisture stress, light, and genetic effects on individual needle parameters and investigate total needle contribution to productivity, individual and total needle parameter variation were quantified in 32-year-old black spruce from five crown positions from four full-sib families studied previously for drought tolerance and differential productivity on...

Change in oak abundance in the eastern United States from 1980 to 2008

Treesearch

Songlin Fei; Ningning Kong; Kim C. Steiner; W. Keith Moser; Eric B. Steiner

2011-01-01

Although oaks (Quercus spp.) have historically dominated much of the forest land in eastern North America, a great deal of fragmentary and sometimes anecdotal evidence suggests that they have been yielding dominance in recent decades to other, typically more shade-tolerant species. Using FIA data, our work formally quantifies the change in oak abundance in the eastern...

Reboxetine for ADHD in children non-responders or with poor tolerance to methylphenidate: a prospective long-term open-label study.

PubMed

Quintero, Javier; López-Muñoz, Francisco; Alamo, Cecilio; Loro, Mercedes; García-Campos, Natalia

2010-11-01

Up to 30% of patients with attention-deficit hyperactivity disorder (ADHD) treated with psychostimulants discontinue the treatment because of intolerance or lack of therapeutic response. Therapeutic alternatives are needed for such patients. In the present case series, we study the effectiveness of reboxetine over a period of 6 months in a sample of 14 children diagnosed with ADHD according to DSM-IV-TR criteria, who had responded only partially or had presented poor tolerance to conventional treatment with methylphenidate. Clinical efficacy was evaluated through the application of the 18-item Attention-Deficit Hyperactivity Disorder Rating Scale (ADHD-RS-IV) and the Clinical Global Impressions-Global Improvement Scale (CGI-I). Percentages of responders (ADHD-RS ≥ 25%) and improvers (CGI-I absolute value < 4) were 90.9 and 72.7%, respectively. No serious side-effects were observed during treatment, the most frequent effects being headaches and insomnia. The initial findings of our study show that reboxetine may constitute an effective tool for long-term treatment of children with ADHD who present poor response or poor tolerance to initial treatment with methylphenidate.

Global-scale high-resolution ( 1 km) modelling of mean, maximum and minimum annual streamflow

NASA Astrophysics Data System (ADS)

Barbarossa, Valerio; Huijbregts, Mark; Hendriks, Jan; Beusen, Arthur; Clavreul, Julie; King, Henry; Schipper, Aafke

2017-04-01

Quantifying mean, maximum and minimum annual flow (AF) of rivers at ungauged sites is essential for a number of applications, including assessments of global water supply, ecosystem integrity and water footprints. AF metrics can be quantified with spatially explicit process-based models, which might be overly time-consuming and data-intensive for this purpose, or with empirical regression models that predict AF metrics based on climate and catchment characteristics. Yet, so far, regression models have mostly been developed at a regional scale and the extent to which they can be extrapolated to other regions is not known. We developed global-scale regression models that quantify mean, maximum and minimum AF as function of catchment area and catchment-averaged slope, elevation, and mean, maximum and minimum annual precipitation and air temperature. We then used these models to obtain global 30 arc-seconds (˜ 1 km) maps of mean, maximum and minimum AF for each year from 1960 through 2015, based on a newly developed hydrologically conditioned digital elevation model. We calibrated our regression models based on observations of discharge and catchment characteristics from about 4,000 catchments worldwide, ranging from 100 to 106 km2 in size, and validated them against independent measurements as well as the output of a number of process-based global hydrological models (GHMs). The variance explained by our regression models ranged up to 90% and the performance of the models compared well with the performance of existing GHMs. Yet, our AF maps provide a level of spatial detail that cannot yet be achieved by current GHMs.

Global charcoal mobilization from soils via dissolution and riverine transport to the oceans

Treesearch

Rudolf Jaffe; Yan Ding; Jutta Niggemann; Anssi V. Vahatalo; Aron Stubbins; Robert G. M. Spencer; John Campbell; Thorsten Dittmar

2013-01-01

Global biomass burning generates 40 million to 250 million tons of charcoal every year, part of which is preserved for millennia in soils and sediments. We have quantified dissolution products of charcoal in a wide range of rivers worldwide and show that globally, a major portion of the annual charcoal production is lost from soils via dissolution and subsequent...

Extremal entanglement and mixedness in continuous variable systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

2004-08-01

We investigate the relationship between mixedness and entanglement for Gaussian states of continuous variable systems. We introduce generalized entropies based on Schatten p norms to quantify the mixedness of a state and derive their explicit expressions in terms of symplectic spectra. We compare the hierarchies of mixedness provided by such measures with the one provided by the purity (defined as tr {rho}{sup 2} for the state {rho}) for generic n-mode states. We then review the analysis proving the existence of both maximally and minimally entangled states at given global and marginal purities, with the entanglement quantified by the logarithmic negativity.more » Based on these results, we extend such an analysis to generalized entropies, introducing and fully characterizing maximally and minimally entangled states for given global and local generalized entropies. We compare the different roles played by the purity and by the generalized p entropies in quantifying the entanglement and the mixedness of continuous variable systems. We introduce the concept of average logarithmic negativity, showing that it allows a reliable quantitative estimate of continuous variable entanglement by direct measurements of global and marginal generalized p entropies.« less

Implications of climate change for agricultural productivity in the early twenty-first century.

PubMed

Gornall, Jemma; Betts, Richard; Burke, Eleanor; Clark, Robin; Camp, Joanne; Willett, Kate; Wiltshire, Andrew

2010-09-27

This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO(2) rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified.

Implications of climate change for agricultural productivity in the early twenty-first century

PubMed Central

Gornall, Jemma; Betts, Richard; Burke, Eleanor; Clark, Robin; Camp, Joanne; Willett, Kate; Wiltshire, Andrew

2010-01-01

This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO2 rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified. PMID:20713397

Mechanisms of yeast stress tolerance and its manipulation for efficient fuel ethanol production.

PubMed

Zhao, X Q; Bai, F W

2009-10-12

Yeast strains of Saccharomyces cerevisiae have been extensively studied in recent years for fuel ethanol production, in which yeast cells are exposed to various stresses such as high temperature, ethanol inhibition, and osmotic pressure from product and substrate sugars as well as the inhibitory substances released from the pretreatment of lignocellulosic biomass. An in-depth understanding of the mechanism of yeast stress tolerance contributes to breeding more robust strains for ethanol production, especially under very high gravity conditions. Taking advantage of the "omics" technology, the stress response and defense mechanism of yeast cells during ethanol fermentation were further explored, and the newly emerged tools such as genome shuffling and global transcription machinery engineering have been applied to breed stress resistant yeast strains for ethanol production. In this review, the latest development of stress tolerance mechanisms was focused, and improvement of yeast stress tolerance by both random and rational tools was presented.

Evaluating and extending user-level fault tolerance in MPI applications

DOE PAGES

Laguna, Ignacio; Richards, David F.; Gamblin, Todd; ...

2016-01-11

The user-level failure mitigation (ULFM) interface has been proposed to provide fault-tolerant semantics in the Message Passing Interface (MPI). Previous work presented performance evaluations of ULFM; yet questions related to its programability and applicability, especially to non-trivial, bulk synchronous applications, remain unanswered. In this article, we present our experiences on using ULFM in a case study with a large, highly scalable, bulk synchronous molecular dynamics application to shed light on the advantages and difficulties of this interface to program fault-tolerant MPI applications. We found that, although ULFM is suitable for master–worker applications, it provides few benefits for more common bulkmore » synchronous MPI applications. Furthermore, to address these limitations, we introduce a new, simpler fault-tolerant interface for complex, bulk synchronous MPI programs with better applicability and support than ULFM for application-level recovery mechanisms, such as global rollback.« less

Benefits of tolerance in public goods games.

PubMed

Szolnoki, Attila; Chen, Xiaojie

2015-10-01

Leaving the joint enterprise when defection is unveiled is always a viable option to avoid being exploited. Although loner strategy helps the population not to be trapped into the tragedy of the commons state, it could offer only a modest income for nonparticipants. In this paper we demonstrate that showing some tolerance toward defectors could not only save cooperation in harsh environments but in fact results in a surprisingly high average payoff for group members in public goods games. Phase diagrams and the underlying spatial patterns reveal the high complexity of evolving states where cyclic dominant strategies or two-strategy alliances can characterize the final state of evolution. We identify microscopic mechanisms which are responsible for the superiority of global solutions containing tolerant players. This phenomenon is robust and can be observed both in well-mixed and in structured populations highlighting the importance of tolerance in our everyday life.

Ammonium and nitrate tolerance in lichens.

PubMed

Hauck, Markus

2010-05-01

Since lichens lack roots and take up water, solutes and gases over the entire thallus surface, these organisms respond more sensitively to changes in atmospheric purity than vascular plants. After centuries where effects of sulphur dioxide and acidity were in the focus of research on atmospheric chemistry and lichens, recently the globally increased levels of ammonia and nitrate increasingly affect lichen vegetation and gave rise to intense research on the tolerance of lichens to nitrogen pollution. The present paper discusses the main findings on the uptake of ammonia and nitrate in the lichen symbiosis and to the tolerance of lichens to eutrophication. Ammonia and nitrate are both efficiently taken up under ambient conditions. The tolerance to high nitrogen levels depends, among others, on the capability of the photobiont to provide sufficient amounts of carbon skeletons for ammonia assimilation. Lowly productive lichens are apparently predisposed to be sensitive to excess nitrogen. Copyright 2010 Elsevier Ltd. All rights reserved.

Salinized rivers: degraded systems or new habitats for salt-tolerant faunas?

PubMed Central

Buchwalter, David; Davis, Jenny

2016-01-01

Anthropogenic salinization of rivers is an emerging issue of global concern, with significant adverse effects on biodiversity and ecosystem functioning. Impacts of freshwater salinization on biota are strongly mediated by evolutionary history, as this is a major factor determining species physiological salinity tolerance. Freshwater insects dominate most flowing waters, and the common lotic insect orders Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies) are particularly salt-sensitive. Tolerances of existing taxa, rapid adaption, colonization by novel taxa (from naturally saline environments) and interactions between species will be key drivers of assemblages in saline lotic systems. Here we outline a conceptual framework predicting how communities may change in salinizing rivers. We envision that a relatively small number of taxa will be saline-tolerant and able to colonize salinized rivers (e.g. most naturally saline habitats are lentic; thus potential colonizers would need to adapt to lotic environments), leading to depauperate communities in these environments. PMID:26932680

A Randomized, Double-Blind, Placebo-Controlled Study to Investigate the Safety, Tolerability, and Pharmacokinetics of Single Enantiomer (+)-Mefloquine Compared with Racemic Mefloquine in Healthy Persons

PubMed Central

Tansley, Robert; Lotharius, Julie; Priestley, Anthony; Bull, Fiona; Duparc, Stephan; Möhrle, Jörg

2010-01-01

Racemic mefloquine is a highly effective antimalarial whose clinical utility has been compromised by its association with neuropsychiatric and gastrointestinal side effects. It is hypothesized that the cause of the side effects may reside in the (−) enantiomer. We sought to compare the safety, tolerability and pharmacokinetic profile of (+)-mefloquine with racemic mefloquine in a randomized, ascending-dose, double-blind, active and placebo-controlled, parallel cohort study in healthy male and female adult volunteers. Although differing in its manifestations, both study drugs displayed a substantially worse tolerability profile compared with placebo. The systemic clearance was slower for (−)-mefloquine than (+)-mefloquine. Thus, (+)-mefloquine has a different safety and tolerability profile compared with racemic mefloquine but its global safety profile is not superior and replacement of the currently used antimalarial drug with (+)-mefloquine is not warranted. PMID:21118921

Tolerance and UQ4SIM: Nimble Uncertainty Documentation and Analysis Software

NASA Technical Reports Server (NTRS)

Kleb, Bil

2008-01-01

Ultimately, scientific numerical models need quantified output uncertainties so that modeling can evolve to better match reality. Documenting model input uncertainties and variabilities is a necessary first step toward that goal. Without known input parameter uncertainties, model sensitivities are all one can determine, and without code verification, output uncertainties are simply not reliable. The basic premise of uncertainty markup is to craft a tolerance and tagging mini-language that offers a natural, unobtrusive presentation and does not depend on parsing each type of input file format. Each file is marked up with tolerances and optionally, associated tags that serve to label the parameters and their uncertainties. The evolution of such a language, often called a Domain Specific Language or DSL, is given in [1], but in final form it parallels tolerances specified on an engineering drawing, e.g., 1 +/- 0.5, 5 +/- 10%, 2 +/- 10 where % signifies percent and o signifies order of magnitude. Tags, necessary for error propagation, can be added by placing a quotation-mark-delimited tag after the tolerance, e.g., 0.7 +/- 20% 'T_effective'. In addition, tolerances might have different underlying distributions, e.g., Uniform, Normal, or Triangular, or the tolerances may merely be intervals due to lack of knowledge (uncertainty). Finally, to address pragmatic considerations such as older models that require specific number-field formats, C-style format specifiers can be appended to the tolerance like so, 1.35 +/- 10U_3.2f. As an example of use, consider figure 1, where a chemical reaction input file is has been marked up to include tolerances and tags per table 1. Not only does the technique provide a natural method of specifying tolerances, but it also servers as in situ documentation of model uncertainties. This tolerance language comes with a utility to strip the tolerances (and tags), to provide a path to the nominal model parameter file. And, as shown in [1], having the ability to quickly mark and identify model parameter uncertainties facilitates error propagation, which in turn yield output uncertainties.

Development of new impact functions for global risk caused by climate change

NASA Astrophysics Data System (ADS)

Miyazaki, C.

2014-12-01

The purpose of our study is to identify and quantify global-scale risks which can be caused by future climate change. In particular, we focus on the global-scale risks which have critical impacts to human environments. Use of impact functions is one of the common way to quantify global-scale risks. Output of impact function is climate impacts (e.g. economic damage by temperature increasing) and input can be global temperature increasing and/or socioeconomic condition (e.g. GDP). As the first step of study, we referred to AR5 WG II report (AR5, hereafter) and comprehensive inventories of climate change risks developed by Strategic R&D Area Project of the Environment Research and Technology Development Fund (ICA-RUS project). Then we extracted information which can be used to develop impact function from them. By following SPM/AR5, we focused on 11 sectors and extracted quantitative description on climate impacts from the AR5 and paper/reports cited in AR5. As a result, we identified about 40 risk items to focus as global-scale risks by climate change. Using the collected information, we tentatively made impact function on sea level rise and so on. In addition, we also extracted the impact functions used in Integrated Assessment Models (IAMs). The literature survey on IAM suggested the risk items considered in IAMs are limited. For instance, although FUND model provides detailed impact functions compared with most of other IAMs, its impact functions deal with only several sectors (e.g. agriculture, forestry, biodiversity, sea level rise, human health, energy demand and water resources). The survey on impact functions in IAMs also suggested impact function for abrupt climate change (so-called Tipping Element) is premature. Moreover, as example for quantifying health risk by our calculation, we also present the result on global-scale projection of the health burden attributable to childhood undernutrition (Ishida et al., 2014, ERL).

Becoming less tolerant with age: sugar maple, shade, and ontogeny.

PubMed

Sendall, Kerrie M; Lusk, Christopher H; Reich, Peter B

2015-12-01

Although shade tolerance is often assumed to be a fixed trait, recent work suggests ontogenetic changes in the light requirements of tree species. We determined the influence of gas exchange, biomass distribution, and self-shading on ontogenetic variation in the instantaneous aboveground carbon balance of Acer saccharum. We quantified the aboveground biomass distributions of 18 juveniles varying in height and growing in low light in a temperate forest understory in Minnesota, USA. Gas exchange rates of leaf and stem tissues were measured, and the crown architecture of each individual was quantified. The YPLANT program was used to estimate the self-shaded fraction of each crown and to model net leaf-level carbon gain. Leaf respiration and photosynthesis per gram of leaf tissue increased with plant size. In contrast, stem respiration rates per gram of stem tissue declined, reflecting a shift in the distribution of stem diameter sizes from smaller (with higher respiration) to larger diameter classes. However, these trends were outweighed by ontogenetic increases in self-shading (which reduces the net photosynthesis realized) and stem mass fraction (which increases the proportion of purely respiratory tissue) in terms of influence on net carbon exchange. As a result, net carbon gain per gram of aboveground plant tissue declined with increasing plant size, and the instantaneous aboveground light compensation point increased. When estimates of root respiration were included to model whole-plant carbon gain and light compensation points, relationships with plant size were even more pronounced. Our findings show how an interplay of gas exchange, self-shading, and biomass distribution shapes ontogenetic changes in shade tolerance.

Relationship between cold pressor pain-sensitivity and sleep quality in opioid-dependent males on methadone treatment

PubMed Central

Lee, Chee Siong; Tan, Soo Choon; Mohamad, Nasir; Lee, Yeong Yeh; Ismail, Rusli

2015-01-01

Aim. Poor sleep quality due to pain has been reported among opioid-dependent male patients on methadone maintenance therapy (MMT) but objective pain data are lacking. This study aimed to investigate the rate of pain-sensitivity using cold pressor test (CPT) and the relationship between pain-sensitivity and sleep quality in this population. Methods. A total of 168 male participants were included into the study. Objective pain-tolerance was evaluated at 0 h and at 24 h after the first CPT. Malay version of the Pittsburgh Sleep Quality Index (PSQI) and the subjective opiate withdrawal scale (SOWS) questionnaires were administered to evaluate the quality of sleep and withdrawal symptoms, respectively. Results. The mean age of study participants was 37.22 (SD 6.20) years old. Mean daily methadone dose was 76.64 (SD 37.63) mg/day, mean global PSQI score was 5.47 (SD 2.74) and mean averaged SOWS score was 5.43 (SD 6.91). The averaged pain-tolerance time ranged from 7 to 300 s with a mean time of 32.16 (SE 2.72) s, slightly below the cut-off score of 37.53 s. More specifically, 78.6% (n = 132) of participants were identified as pain-sensitive (averaged pain-tolerance time ≤37.53 s), and 36 (21.4%) participants were pain-tolerant (averaged pain-tolerance time >37.53 s). The pain-sensitive group reported poorer sleep quality with mean (SD) PSQI of 5.78 (2.80) compared with the pain-tolerant group with mean (SD) PSQI of 4.31 (2.18) (p = 0.005). With analysis of covariance, pain-sensitive group was found to have higher global PSQI scores (adjusted mean 5.76, 95% CI 5.29; 6.22) than pain-tolerant participants (adjusted mean 4.42, 95% CI 3.52; 5.32) (p = 0.010). Conclusions. Majority of opioid-dependent male patients on methadone treatment are pain-sensitive with CPT. Poor sleep quality is associated with cold pressor pain-sensitivity. Pain and sleep complaints in this male population should not be overlooked. PMID:25870765

Texture Analysis of Poly-Adenylated mRNA Staining Following Global Brain Ischemia and Reperfusion

PubMed Central

Szymanski, Jeffrey J.; Jamison, Jill T.; DeGracia, Donald J.

2011-01-01

Texture analysis provides a means to quantify complex changes in microscope images. We previously showed that cytoplasmic poly-adenylated mRNAs form mRNA granules in post-ischemic neurons and that these granules correlated with protein synthesis inhibition and hence cell death. Here we utilized the texture analysis software MaZda to quantify mRNA granules in photomicrographs of the pyramidal cell layer of rat hippocampal region CA3 around 1 hour of reperfusion after 10 min of normothermic global cerebral ischemia. At 1 hour reperfusion, we observed variations in the texture of mRNA granules amongst samples that were readily quantified by texture analysis. Individual sample variation was consistent with the interpretation that animal-to-animal variations in mRNA granules reflected the time-course of mRNA granule formation. We also used texture analysis to quantify the effect of cycloheximide, given either before or after brain ischemia, on mRNA granules. If administered before ischemia, cycloheximide inhibited mRNA granule formation, but if administered after ischemia did not prevent mRNA granulation, indicating mRNA granule formation is dependent on dissociation of polysomes. We conclude that texture analysis is an effective means for quantifying the complex morphological changes induced in neurons by brain ischemia and reperfusion. PMID:21477879

DOE Office of Scientific and Technical Information (OSTI.GOV)

St James, S; Bloch, C; Saini, J

Purpose: Proton pencil beam scanning is used clinically across the United States. There are no current guidelines on tolerances for daily QA specific to pencil beam scanning, specifically related to the individual spot properties (spot width). Using a stochastic method to determine tolerances has the potential to optimize tolerances on individual spots and decrease the number of false positive failures in daily QA. Individual and global spot tolerances were evaluated. Methods: As part of daily QA for proton pencil beam scanning, a field of 16 spots (corresponding to 8 energies) is measured using an array of ion chambers (Matrixx, IBA).more » Each individual spot is fit to two Gaussian functions (x,y). The spot width (σ) in × and y are recorded (32 parameters). Results from the daily QA were retrospectively analyzed for 100 days of data. The deviations of the spot widths were histogrammed and fit to a Gaussian function. The stochastic spot tolerance was taken to be the mean ± 3σ. Using these results, tolerances were developed and tested against known deviations in spot width. Results: The individual spot tolerances derived with the stochastic method decreased in 30/32 instances. Using the previous tolerances (± 20% width), the daily QA would have detected 0/20 days of the deviation. Using a tolerance of any 6 spots failing the stochastic tolerance, 18/20 days of the deviation would have been detected. Conclusion: Using a stochastic method we have been able to decrease daily tolerances on the spot widths for 30/32 spot widths measured. The stochastic tolerances can lead to detection of deviations that previously would have been picked up on monthly QA and missed by daily QA. This method could be easily extended for evaluation of other QA parameters in proton spot scanning.« less

QuantFusion: Novel Unified Methodology for Enhanced Coverage and Precision in Quantifying Global Proteomic Changes in Whole Tissues.

PubMed

Gunawardena, Harsha P; O'Brien, Jonathon; Wrobel, John A; Xie, Ling; Davies, Sherri R; Li, Shunqiang; Ellis, Matthew J; Qaqish, Bahjat F; Chen, Xian

2016-02-01

Single quantitative platforms such as label-based or label-free quantitation (LFQ) present compromises in accuracy, precision, protein sequence coverage, and speed of quantifiable proteomic measurements. To maximize the quantitative precision and the number of quantifiable proteins or the quantifiable coverage of tissue proteomes, we have developed a unified approach, termed QuantFusion, that combines the quantitative ratios of all peptides measured by both LFQ and label-based methodologies. Here, we demonstrate the use of QuantFusion in determining the proteins differentially expressed in a pair of patient-derived tumor xenografts (PDXs) representing two major breast cancer (BC) subtypes, basal and luminal. Label-based in-spectra quantitative peptides derived from amino acid-coded tagging (AACT, also known as SILAC) of a non-malignant mammary cell line were uniformly added to each xenograft with a constant predefined ratio, from which Ratio-of-Ratio estimates were obtained for the label-free peptides paired with AACT peptides in each PDX tumor. A mixed model statistical analysis was used to determine global differential protein expression by combining complementary quantifiable peptide ratios measured by LFQ and Ratio-of-Ratios, respectively. With minimum number of replicates required for obtaining the statistically significant ratios, QuantFusion uses the distinct mechanisms to "rescue" the missing data inherent to both LFQ and label-based quantitation. Combined quantifiable peptide data from both quantitative schemes increased the overall number of peptide level measurements and protein level estimates. In our analysis of the PDX tumor proteomes, QuantFusion increased the number of distinct peptide ratios by 65%, representing differentially expressed proteins between the BC subtypes. This quantifiable coverage improvement, in turn, not only increased the number of measurable protein fold-changes by 8% but also increased the average precision of quantitative estimates by 181% so that some BC subtypically expressed proteins were rescued by QuantFusion. Thus, incorporating data from multiple quantitative approaches while accounting for measurement variability at both the peptide and global protein levels make QuantFusion unique for obtaining increased coverage and quantitative precision for tissue proteomes. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Identification of Putative Transmembrane Proteins Involved in Salinity Tolerance in Chenopodium quinoa by Integrating Physiological Data, RNAseq, and SNP Analyses

PubMed Central

Schmöckel, Sandra M.; Lightfoot, Damien J.; Razali, Rozaimi; Tester, Mark; Jarvis, David E.

2017-01-01

Chenopodium quinoa (quinoa) is an emerging crop that produces nutritious grains with the potential to contribute to global food security. Quinoa can also grow on marginal lands, such as soils affected by high salinity. To identify candidate salt tolerance genes in the recently sequenced quinoa genome, we used a multifaceted approach integrating RNAseq analyses with comparative genomics and topology prediction. We identified 219 candidate genes by selecting those that were differentially expressed in response to salinity, were specific to or overrepresented in quinoa relative to other Amaranthaceae species, and had more than one predicted transmembrane domain. To determine whether these genes might underlie variation in salinity tolerance in quinoa and its close relatives, we compared the response to salinity stress in a panel of 21 Chenopodium accessions (14 C. quinoa, 5 C. berlandieri, and 2 C. hircinum). We found large variation in salinity tolerance, with one C. hircinum displaying the highest salinity tolerance. Using genome re-sequencing data from these accessions, we investigated single nucleotide polymorphisms and copy number variation (CNV) in the 219 candidate genes in accessions of contrasting salinity tolerance, and identified 15 genes that could contribute to the differences in salinity tolerance of these Chenopodium accessions. PMID:28680429

Reproductive stage physiological and transcriptional responses to salinity stress in reciprocal populations derived from tolerant (Horkuch) and susceptible (IR29) rice

NASA Astrophysics Data System (ADS)

Razzaque, Samsad; Haque, Taslima; Elias, Sabrina M.; Rahman, Md. Sazzadur; Biswas, Sudip; Schwartz, Scott; Ismail, Abdelbagi M.; Walia, Harkamal; Juenger, Thomas E.; Seraj, Zeba I.

2017-04-01

Global increase in salinity levels has made it imperative to identify novel sources of genetic variation for tolerance traits, especially in rice. The rice landrace Horkuch, endemic to the saline coastal area of Bangladesh, was used in this study as the source of tolerance in reciprocal crosses with the sensitive but high-yielding IR29 variety for discovering transcriptional variation associated with salt tolerance in the resulting populations. The cytoplasmic effect of the Horkuch background in leaves under stress showed functional enrichment for signal transduction, DNA-dependent regulation and transport activities. In roots the enrichment was for cell wall organization and macromolecule biosynthesis. In contrast, the cytoplasmic effect of IR29 showed upregulation of apoptosis and downregulation of phosphorylation across tissues relative to Horkuch. Differential gene expression in leaves of the sensitive population showed downregulation of GO processes like photosynthesis, ATP biosynthesis and ion transport. Roots of the tolerant plants conversely showed upregulation of GO terms like G-protein coupled receptor pathway, membrane potential and cation transport. Furthermore, genes involved in regulating membrane potentials were constitutively expressed only in the roots of tolerant individuals. Overall our work has developed genetic resources and elucidated the likely mechanisms associated with the tolerance response of the Horkuch genotype.

Engineering of global regulators and cell surface properties toward enhancing stress tolerance in Saccharomyces cerevisiae.

PubMed

Kuroda, Kouichi; Ueda, Mitsuyoshi

2017-12-01

Microbial cell factories are subject to various stresses, leading to the reductions of metabolic activity and bioproduction efficiency. Therefore, the development of stress-tolerant microorganisms is important for improving bio-production efficiency. Recently, modifications of cell surface properties and master regulators have been shown to be effective approaches for enhancing stress tolerance. The cell surface is an attractive target owing to its interactions with the environment and its role in transmitting environmental information. Cell surface engineering in yeast has enabled the convenient modification of cell surface properties. Displaying random peptide libraries and subsequent screening can successfully improve stress tolerance. Furthermore, master regulators including transcription factors are also promising target to be engineered because stress tolerance is determined by many cooperative factors and modification of master regulators can simultaneously affect the expression of multiple downstream genes. The key single amino acid mutations in transcription factors have been identified by analyzing tolerant yeasts that were isolated by adaptive evolution under stress conditions. This enabled the reconstruction of stress-tolerant yeast without burdening cells by introducing the identified mutations. Therefore, for the construction of stress-tolerant yeast from any strains, these two approaches are promising alternatives to conventional overexpression and deletion of stress-related genes. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Susceptibility and tolerance of rice crop to salt threat: Physiological and metabolic inspections

PubMed Central

Che Lah, Wan Afifudeen; Abd. Kadir, Nisrin; Mustaqim, Mohamad; Rahmat, Zaidah; Ahmad, Aziz; Ismail, Mohd Razi

2018-01-01

Salinity threat is estimated to reduce global rice production by 50%. Comprehensive analysis of the physiological and metabolite changes in rice plants from salinity stress (i.e. tolerant versus susceptible plants) is important to combat higher salinity conditions. In this study, we screened a total of 92 genotypes and selected the most salinity tolerant line (SS1-14) and most susceptible line (SS2-18) to conduct comparative physiological and metabolome inspections. We demonstrated that the tolerant line managed to maintain their water and chlorophyll content with lower incidence of sodium ion accumulation. We also examined the antioxidant activities of these lines: production of ascorbate peroxidase (APX) and catalase (CAT) were significantly higher in the sensitive line while superoxide dismutase (SOD) was higher in the tolerant line. Partial least squares discriminant analysis (PLS-DA) score plots show significantly different response for both lines after the exposure to salinity stress. In the tolerant line, there was an upregulation of non-polar metabolites and production of sucrose, GABA and acetic acid, suggesting an important role in salinity adaptation. In contrast, glutamine and putrescine were noticeably high in the susceptible rice. Coordination of different strategies in tolerant and susceptible lines show that they responded differently after exposure to salt stress. These findings can assist crop development in terms of developing tolerance mechanisms for rice crops. PMID:29489838

Generating high temperature tolerant transgenic plants: Achievements and challenges.

PubMed

Grover, Anil; Mittal, Dheeraj; Negi, Manisha; Lavania, Dhruv

2013-05-01

Production of plants tolerant to high temperature stress is of immense significance in the light of global warming and climate change. Plant cells respond to high temperature stress by re-programming their genetic machinery for survival and reproduction. High temperature tolerance in transgenic plants has largely been achieved either by over-expressing heat shock protein genes or by altering levels of heat shock factors that regulate expression of heat shock and non-heat shock genes. Apart from heat shock factors, over-expression of other trans-acting factors like DREB2A, bZIP28 and WRKY proteins has proven useful in imparting high temperature tolerance. Besides these, elevating the genetic levels of proteins involved in osmotic adjustment, reactive oxygen species removal, saturation of membrane-associated lipids, photosynthetic reactions, production of polyamines and protein biosynthesis process have yielded positive results in equipping transgenic plants with high temperature tolerance. Cyclic nucleotide gated calcium channel proteins that regulate calcium influxes across the cell membrane have recently been shown to be the key players in induction of high temperature tolerance. The involvement of calmodulins and kinases in activation of heat shock factors has been implicated as an important event in governing high temperature tolerance. Unfilled gaps limiting the production of high temperature tolerant transgenic plants for field level cultivation are discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Quantifying the underlying landscape and paths of cancer

PubMed Central

Li, Chunhe; Wang, Jin

2014-01-01

Cancer is a disease regulated by the underlying gene networks. The emergence of normal and cancer states as well as the transformation between them can be thought of as a result of the gene network interactions and associated changes. We developed a global potential landscape and path framework to quantify cancer and associated processes. We constructed a cancer gene regulatory network based on the experimental evidences and uncovered the underlying landscape. The resulting tristable landscape characterizes important biological states: normal, cancer and apoptosis. The landscape topography in terms of barrier heights between stable state attractors quantifies the global stability of the cancer network system. We propose two mechanisms of cancerization: one is by the changes of landscape topography through the changes in regulation strengths of the gene networks. The other is by the fluctuations that help the system to go over the critical barrier at fixed landscape topography. The kinetic paths from least action principle quantify the transition processes among normal state, cancer state and apoptosis state. The kinetic rates provide the quantification of transition speeds among normal, cancer and apoptosis attractors. By the global sensitivity analysis of the gene network parameters on the landscape topography, we uncovered some key gene regulations determining the transitions between cancer and normal states. This can be used to guide the design of new anti-cancer tactics, through cocktail strategy of targeting multiple key regulation links simultaneously, for preventing cancer occurrence or transforming the early cancer state back to normal state. PMID:25232051

Dynamic stability of passive dynamic walking on an irregular surface.

PubMed

Su, Jimmy Li-Shin; Dingwell, Jonathan B

2007-12-01

Falls that occur during walking are a significant health problem. One of the greatest impediments to solve this problem is that there is no single obviously "correct" way to quantify walking stability. While many people use variability as a proxy for stability, measures of variability do not quantify how the locomotor system responds to perturbations. The purpose of this study was to determine how changes in walking surface variability affect changes in both locomotor variability and stability. We modified an irreducibly simple model of walking to apply random perturbations that simulated walking over an irregular surface. Because the model's global basin of attraction remained fixed, increasing the amplitude of the applied perturbations directly increased the risk of falling in the model. We generated ten simulations of 300 consecutive strides of walking at each of six perturbation amplitudes ranging from zero (i.e., a smooth continuous surface) up to the maximum level the model could tolerate without falling over. Orbital stability defines how a system responds to small (i.e., "local") perturbations from one cycle to the next and was quantified by calculating the maximum Floquet multipliers for the model. Local stability defines how a system responds to similar perturbations in real time and was quantified by calculating short-term and long-term local exponential rates of divergence for the model. As perturbation amplitudes increased, no changes were seen in orbital stability (r(2)=2.43%; p=0.280) or long-term local instability (r(2)=1.0%; p=0.441). These measures essentially reflected the fact that the model never actually "fell" during any of our simulations. Conversely, the variability of the walker's kinematics increased exponentially (r(2)>or=99.6%; p<0.001) and short-term local instability increased linearly (r(2)=88.1%; p<0.001). These measures thus predicted the increased risk of falling exhibited by the model. For all simulated conditions, the walker remained orbitally stable, while exhibiting substantial local instability. This was because very small initial perturbations diverged away from the limit cycle, while larger initial perturbations converged toward the limit cycle. These results provide insight into how these different proposed measures of walking stability are related to each other and to risk of falling.

CoinCalc-A new R package for quantifying simultaneities of event series

NASA Astrophysics Data System (ADS)

Siegmund, Jonatan F.; Siegmund, Nicole; Donner, Reik V.

2017-01-01

We present the new R package CoinCalc for performing event coincidence analysis (ECA), a novel statistical method to quantify the simultaneity of events contained in two series of observations, either as simultaneous or lagged coincidences within a user-specific temporal tolerance window. The package also provides different analytical as well as surrogate-based significance tests (valid under different assumptions about the nature of the observed event series) as well as an intuitive visualization of the identified coincidences. We demonstrate the usage of CoinCalc based on two typical geoscientific example problems addressing the relationship between meteorological extremes and plant phenology as well as that between soil properties and land cover.

GLOBAL ASSESSMENT OF WASTEWATER IRRIGATION: UNDERSTANDING HEALTH RISKS AND CONTRIBUTIONS TO FOOD SECURITY USING AN ENVIRONMENTAL SYSTEMS APPROACH

EPA Science Inventory

This research will quantify the extent of de facto reuse of untreated wastewater at the global scale. Through the integration of multiple existing spatial data sources, this project will produce rigorous analyses assessing the relationship between wastewater irrigation, hea...

The Tolerability Profile of Clindamycin 1%/Benzoyl Peroxide 5% Gel vs. Adapalene 0.1%/Benzoyl Peroxide 2.5% Gel for Facial Acne

PubMed Central

Cirigliano, Marcela; Gwazdauskas, Jennifer A; Gonzalez, Pablo

2012-01-01

Objective: To compare the first two weeks of tolerability of clindamycin/benzoyl peroxide gel versus adapalene/benzoyl peroxide gel followed by six weeks of open-label clindamycin/benzoyl peroxide gel therapy in subjects with mild-to-moderate acne who participated in two eight-week, identically designed, clinical studies. Methods: Using a split-face method, patients received both clindamycin/benzoyl peroxide gel and adapalene/benzoyl peroxide gel once daily for two weeks (allocation to the right or left side of the face was randomized) in an investigator-blinded fashion. Patients then went on to receive a further six weeks of open-label, full-face clindamycin/benzoyl peroxide gel. The primary outcome was to compare signs and symptoms of tolerability during the first two weeks of treatment using an investigator-assessed 4-point rating scale. Secondary endpoints included assessment of acne severity (Investigator Static Global Assessment and lesion counts), quality of life, product acceptability/preference, and patient assessments of tolerability and safety. Results: Of the 76 subjects enrolled in the two studies, 72 completed them. Overall both products were well tolerated, but mean scores for erythema, dryness, and peeling were significantly higher with adapalene/benzoyl peroxide gel than with clindamycin/benzoyl peroxide gel at both Weeks 1 and 2 (p<0.03). Patients also rated clindamycin/benzoyl peroxide gel significantly more tolerable than adapalene/benzoyl peroxide gel for redness, dryness, burning, itching, and scaling at Weeks 1 and 2 (p 0.0073). Mean Investigator Static Global Assessment score improved with both products during the first two weeks of treatment and continued to show significant improvement versus baseline when treatment with clindamycin/benzoyl peroxide gel was continued for a further six weeks (p<0.001 at Week 8). Lesion counts improved throughout the study with significant reductions from baseline occurring at Weeks 5 and 8 (p<0.0001 for both time points for total lesion counts). Clindamycin/benzoyl peroxide gel and adapalene/benzoyl peroxide gel were well tolerated, with most adverse events of mild-to-moderate severity. Conclusion: Clindamycin/benzoyl peroxide gel had better tolerability with regard to erythema, dryness, and peeling than adapalene/benzoyl peroxide gel during the first two weeks of treatment. PMID:22808305

Respiratory control in aquatic insects dictates their vulnerability to global warming

PubMed Central

Verberk, Wilco C. E. P.; Bilton, David T.

2013-01-01

Forecasting species responses to climatic warming requires knowledge of how temperature impacts may be exacerbated by other environmental stressors, hypoxia being a principal example in aquatic systems. Both stressors could interact directly as temperature affects both oxygen bioavailability and ectotherm oxygen demand. Insufficient oxygen has been shown to limit thermal tolerance in several aquatic ectotherms, although, the generality of this mechanism has been challenged for tracheated arthropods. Comparing species pairs spanning four different insect orders, we demonstrate that oxygen can indeed limit thermal tolerance in tracheates. Species that were poor at regulating oxygen uptake were consistently more vulnerable to the synergistic effects of warming and hypoxia, demonstrating the importance of respiratory control in setting thermal tolerance limits. PMID:23925834

Respiratory control in aquatic insects dictates their vulnerability to global warming.

PubMed

Verberk, Wilco C E P; Bilton, David T

2013-10-23

Forecasting species responses to climatic warming requires knowledge of how temperature impacts may be exacerbated by other environmental stressors, hypoxia being a principal example in aquatic systems. Both stressors could interact directly as temperature affects both oxygen bioavailability and ectotherm oxygen demand. Insufficient oxygen has been shown to limit thermal tolerance in several aquatic ectotherms, although, the generality of this mechanism has been challenged for tracheated arthropods. Comparing species pairs spanning four different insect orders, we demonstrate that oxygen can indeed limit thermal tolerance in tracheates. Species that were poor at regulating oxygen uptake were consistently more vulnerable to the synergistic effects of warming and hypoxia, demonstrating the importance of respiratory control in setting thermal tolerance limits.

Engineering yeast transcription machinery for improved ethanol tolerance and production.

PubMed

Alper, Hal; Moxley, Joel; Nevoigt, Elke; Fink, Gerald R; Stephanopoulos, Gregory

2006-12-08

Global transcription machinery engineering (gTME) is an approach for reprogramming gene transcription to elicit cellular phenotypes important for technological applications. Here we show the application of gTME to Saccharomyces cerevisiae for improved glucose/ethanol tolerance, a key trait for many biofuels programs. Mutagenesis of the transcription factor Spt15p and selection led to dominant mutations that conferred increased tolerance and more efficient glucose conversion to ethanol. The desired phenotype results from the combined effect of three separate mutations in the SPT15 gene [serine substituted for phenylalanine (Phe(177)Ser) and, similarly, Tyr(195)His, and Lys(218)Arg]. Thus, gTME can provide a route to complex phenotypes that are not readily accessible by traditional methods.

Error and attack tolerance of complex networks

NASA Astrophysics Data System (ADS)

Albert, Réka; Jeong, Hawoong; Barabási, Albert-László

2000-07-01

Many complex systems display a surprising degree of tolerance against errors. For example, relatively simple organisms grow, persist and reproduce despite drastic pharmaceutical or environmental interventions, an error tolerance attributed to the robustness of the underlying metabolic network. Complex communication networks display a surprising degree of robustness: although key components regularly malfunction, local failures rarely lead to the loss of the global information-carrying ability of the network. The stability of these and other complex systems is often attributed to the redundant wiring of the functional web defined by the systems' components. Here we demonstrate that error tolerance is not shared by all redundant systems: it is displayed only by a class of inhomogeneously wired networks, called scale-free networks, which include the World-Wide Web, the Internet, social networks and cells. We find that such networks display an unexpected degree of robustness, the ability of their nodes to communicate being unaffected even by unrealistically high failure rates. However, error tolerance comes at a high price in that these networks are extremely vulnerable to attacks (that is, to the selection and removal of a few nodes that play a vital role in maintaining the network's connectivity). Such error tolerance and attack vulnerability are generic properties of communication networks.

Genetic markers for antioxidant capacity in a reef-building coral.

PubMed

Jin, Young K; Lundgren, Petra; Lutz, Adrian; Raina, Jean-Baptiste; Howells, Emily J; Paley, Allison S; Willis, Bette L; van Oppen, Madeleine J H

2016-05-01

The current lack of understanding of the genetic basis underlying environmental stress tolerance in reef-building corals impairs the development of new management approaches to confronting the global demise of coral reefs. On the Great Barrier Reef (GBR), an approximately 51% decline in coral cover occurred over the period 1985-2012. We conducted a gene-by-environment association analysis across 12° latitude on the GBR, as well as both in situ and laboratory genotype-by-phenotype association analyses. These analyses allowed us to identify alleles at two genetic loci that account for differences in environmental stress tolerance and antioxidant capacity in the common coral Acropora millepora. The effect size for antioxidant capacity was considerable and biologically relevant (32.5 and 14.6% for the two loci). Antioxidant capacity is a critical component of stress tolerance because a multitude of environmental stressors cause increased cellular levels of reactive oxygen species. Our findings provide the first step toward the development of novel coral reef management approaches, such as spatial mapping of stress tolerance for use in marine protected area design, identification of stress-tolerant colonies for assisted migration, and marker-assisted selective breeding to create more tolerant genotypes for restoration of denuded reefs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caridade, Marta; Graca, Luis; Ribeiro, Ruy M.

To maintain immunological balance the organism has to be tolerant to self while remaining competent to mount an effective immune response against third-party antigens. An important mechanism of this immune regulation involves the action of regulatory T-cell (Tregs). In this mini-review, we discuss some of the known and proposed mechanisms by which Tregs exert their influence in the context of immune regulation, and the contribution of mathematical modeling for these mechanistic studies. These models explore the mechanisms of action of regulatory T cells, and include hypotheses of multiple signals, delivered through simultaneous antigen-presenting cell (APC) conjugation; interaction of feedback loopsmore » between APC, Tregs, and effector cells; or production of specific cytokines that act on effector cells. As the field matures, and competing models are winnowed out, it is likely that we will be able to quantify how tolerance-inducing strategies, such as CD4-blockade, affect T-cell dynamics and what mechanisms explain the observed behavior of T-cell based tolerance.« less

Impacts of Larval Connectivity on Coral Heat Tolerance

NASA Astrophysics Data System (ADS)

Pinsky, M. L.; Kleypas, J. A.; Thompson, D. M.; Castruccio, F. S.; Curchitser, E. N.; Watson, J. R.

2016-02-01

The sensitivity of corals to elevated temperature depends on their acclimation and adaptation to the local maximum temperature regime. Through larval dispersal, however, coral populations can receive larvae from regions that are significantly warmer or colder. If these exogenous larvae carry genetic-based tolerances to colder or warmer temperatures, then the thermal sensitivity of the receiving population may be lower or higher, respectively. Using a high-resolution Regional Ocean Modeling System (ROMS) configuration for the Coral Triangle region, we quantify the potential role of connectivity in determining the thermal stress threshold (TST) of a typical broadcast spawner. The model results suggest that even with a pelagic larval dispersal period of only 10 days, many reefs receive larvae from reefs that are warmer or cooler than the local temperature, and that accounting for this connectivity improves bleaching predictions. This has important implications for conservation planning, because connectivity may allow some reefs to have an inherited heat tolerance that is higher or lower than would be predicted based on local conditions alone.

Human psychopharmacology of N,N-dimethyltryptamine.

PubMed

Strassman, R J

1996-01-01

We generated dose-response data for the endogenous and ultra-short-acting hallucinogen, N,N-dimethyltryptamine (DMT), in a cohort of experienced hallucinogen users, measuring multiple biological and psychological outcome measures. Subjective responses were quantified with a new rating scale, the HRS, which provided better resolution of dose effects than did the biological variables. A tolerance study then was performed, in which volunteers received four closely spaced hallucinogenic doses of DMT. Subjective responses demonstrated no tolerance, while biological measures were inconsistently reduced over the course of the sessions. Thus, DMT remains unique among classic hallucinogens in its inability to induce tolerance to its psychological effects. To assess the role of the 5-HT1A site in mediating DMT's effects, a pindolol pre-treatment study was performed. Pindolol significantly increased psychological responses to DMT, suggesting a buffering effect of 5-HT1A agonism on 5-HT2-mediated psychedelic effects. These data are opposite to those described in lower animal models of hallucinogens' mechanisms of action.

The Infeasibility of Quantifying the Reliability of Life-Critical Real-Time Software

NASA Technical Reports Server (NTRS)

Butler, Ricky W.; Finelli, George B.

1991-01-01

This paper affirms that the quantification of life-critical software reliability is infeasible using statistical methods whether applied to standard software or fault-tolerant software. The classical methods of estimating reliability are shown to lead to exhorbitant amounts of testing when applied to life-critical software. Reliability growth models are examined and also shown to be incapable of overcoming the need for excessive amounts of testing. The key assumption of software fault tolerance separately programmed versions fail independently is shown to be problematic. This assumption cannot be justified by experimentation in the ultrareliability region and subjective arguments in its favor are not sufficiently strong to justify it as an axiom. Also, the implications of the recent multiversion software experiments support this affirmation.

Decadal trends in global pelagic ocean chlorophyll: A new assessment integrating multiple satellites, in situ data, and models.

PubMed

Gregg, Watson W; Rousseaux, Cécile S

2014-09-01

Quantifying change in ocean biology using satellites is a major scientific objective. We document trends globally for the period 1998-2012 by integrating three diverse methodologies: ocean color data from multiple satellites, bias correction methods based on in situ data, and data assimilation to provide a consistent and complete global representation free of sampling biases. The results indicated no significant trend in global pelagic ocean chlorophyll over the 15 year data record. These results were consistent with previous findings that were based on the first 6 years and first 10 years of the SeaWiFS mission. However, all of the Northern Hemisphere basins (north of 10° latitude), as well as the Equatorial Indian basin, exhibited significant declines in chlorophyll. Trend maps showed the local trends and their change in percent per year. These trend maps were compared with several other previous efforts using only a single sensor (SeaWiFS) and more limited time series, showing remarkable consistency. These results suggested the present effort provides a path forward to quantifying global ocean trends using multiple satellite missions, which is essential if we are to understand the state, variability, and possible changes in the global oceans over longer time scales.

Variation in temperature tolerance among families of Atlantic salmon (Salmo salar) is associated with hypoxia tolerance, ventricle size and myoglobin level.

PubMed

Anttila, Katja; Dhillon, Rashpal S; Boulding, Elizabeth G; Farrell, Anthony P; Glebe, Brian D; Elliott, Jake A K; Wolters, William R; Schulte, Patricia M

2013-04-01

In fishes, performance failure at high temperature is thought to be due to a limitation on oxygen delivery (the theory of oxygen and capacity limited thermal tolerance, OCLTT), which suggests that thermal tolerance and hypoxia tolerance might be functionally associated. Here we examined variation in temperature and hypoxia tolerance among 41 families of Atlantic salmon (Salmo salar), which allowed us to evaluate the association between these two traits. Both temperature and hypoxia tolerance varied significantly among families and there was a significant positive correlation between critical maximum temperature (CTmax) and hypoxia tolerance, supporting the OCLTT concept. At the organ and cellular levels, we also discovered support for the OCLTT concept as relative ventricle mass (RVM) and cardiac myoglobin (Mb) levels both correlated positively with CTmax (R(2)=0.21, P<0.001 and R(2)=0.17, P=0.003, respectively). A large RVM has previously been shown to be associated with high cardiac output, which might facilitate tissue oxygen supply during elevated oxygen demand at high temperatures, while Mb facilitates the oxygen transfer from the blood to tissues, especially during hypoxia. The data presented here demonstrate for the first time that RVM and Mb are correlated with increased upper temperature tolerance in fish. High phenotypic variation between families and greater similarity among full- and half-siblings suggests that there is substantial standing genetic variation in thermal and hypoxia tolerance, which could respond to selection either in aquaculture or in response to anthropogenic stressors such as global climate change.

Understanding extreme sea levels for broad-scale coastal impact and adaptation analysis

NASA Astrophysics Data System (ADS)

Wahl, T.; Haigh, I. D.; Nicholls, R. J.; Arns, A.; Dangendorf, S.; Hinkel, J.; Slangen, A. B. A.

2017-07-01

One of the main consequences of mean sea level rise (SLR) on human settlements is an increase in flood risk due to an increase in the intensity and frequency of extreme sea levels (ESL). While substantial research efforts are directed towards quantifying projections and uncertainties of future global and regional SLR, corresponding uncertainties in contemporary ESL have not been assessed and projections are limited. Here we quantify, for the first time at global scale, the uncertainties in present-day ESL estimates, which have by default been ignored in broad-scale sea-level rise impact assessments to date. ESL uncertainties exceed those from global SLR projections and, assuming that we meet the Paris agreement goals, the projected SLR itself by the end of the century in many regions. Both uncertainties in SLR projections and ESL estimates need to be understood and combined to fully assess potential impacts and adaptation needs.

Creation of forest edges has a global impact on forest vertebrates

PubMed Central

Peres, CA; Banks-Leite, C; Wearn, OR; Marsh, CJ; Butchart, SHM; Arroyo-Rodríguez, V; Barlow, J; Cerezo, A; Cisneros, L; D’Cruze, N; Faria, D; Hadley, A; Harris, S; Klingbeil, BT; Kormann, U; Lens, L; Medina-Rangel, GF; Morante-Filho, JC; Olivier, P; Peters, SL; Pidgeon, A; Ribeiro, DB; Scherber, C; Schneider-Maunory, L; Struebig, M; Urbina-Cardona, N; Watling, JI; Willig, MR; Wood, EM; Ewers, RM

2017-01-01

Summary Forest edges influence more than half the world’s forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. We assembled an unmatched global dataset on species responses to fragmentation and developed a new statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1673 vertebrate species. We show that 85% of species’ abundances are affected, either positively or negatively, by forest edges. Forest core species, which were more likely to be listed as threatened by the IUCN, only reached peak abundances at sites farther than 200-400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale. PMID:29088701

A City and National Metric measuring Isolation from the Global Market for Food Security Assessment

NASA Technical Reports Server (NTRS)

Brown, Molly E.; Silver, Kirk Coleman; Rajagopalan, Krishnan

2013-01-01

The World Bank has invested in infrastructure in developing countries for decades. This investment aims to reduce the isolation of markets, reducing both seasonality and variability in food availability and food prices. Here we combine city market price data, global distance to port, and country infrastructure data to create a new Isolation Index for countries and cities around the world. Our index quantifies the isolation of a city from the global market. We demonstrate that an index built at the country level can be applied at a sub-national level to quantify city isolation. In doing so, we offer policy makers with an alternative metric to assess food insecurity. We compare our isolation index with other indices and economic data found in the literature.We show that our Index measures economic isolation regardless of economic stability using correlation and analysis

Using Space Lidar Observations to Decompose Longwave Cloud Radiative Effect Variations Over the Last Decade

NASA Astrophysics Data System (ADS)

Vaillant de Guélis, Thibault; Chepfer, Hélène; Noel, Vincent; Guzman, Rodrigo; Winker, David M.; Plougonven, Riwal

2017-12-01

Measurements of the longwave cloud radiative effect (LWCRE) at the top of the atmosphere assess the contribution of clouds to the Earth warming but do not quantify the cloud property variations that are responsible for the LWCRE variations. The CALIPSO space lidar observes directly the detailed profile of cloud, cloud opacity, and cloud cover. Here we use these observations to quantify the influence of cloud properties on the variations of the LWCRE observed between 2008 and 2015 in the tropics and at global scale. At global scale, the method proposed here gives good results except over the Southern Ocean. We find that the global LWCRE variations observed over ocean are mostly due to variations in the opaque cloud properties (82%); transparent cloud columns contributed 18%. Variation of opaque cloud cover is the first contributor to the LWCRE evolution (58%); opaque cloud temperature is the second contributor (28%).

Iron control on global productivity: an efficient inverse model of the ocean's coupled phosphate and iron cycles.

NASA Astrophysics Data System (ADS)

Pasquier, B.; Holzer, M.; Frants, M.

2016-02-01

We construct a data-constrained mechanistic inverse model of the ocean's coupled phosphorus and iron cycles. The nutrient cycling is embedded in a data-assimilated steady global circulation. Biological nutrient uptake is parameterized in terms of nutrient, light, and temperature limitations on growth for two classes of phytoplankton that are not transported explicitly. A matrix formulation of the discretized nutrient tracer equations allows for efficient numerical solutions, which facilitates the objective optimization of the key biogeochemical parameters. The optimization minimizes the misfit between the modelled and observed nutrient fields of the current climate. We systematically assess the nonlinear response of the biological pump to changes in the aeolian iron supply for a variety of scenarios. Specifically, Green-function techniques are employed to quantify in detail the pathways and timescales with which those perturbations are propagated throughout the world oceans, determining the global teleconnections that mediate the response of the global ocean ecosystem. We confirm previous findings from idealized studies that increased iron fertilization decreases biological production in the subtropical gyres and we quantify the counterintuitive and asymmetric response of global productivity to increases and decreases in the aeolian iron supply.

Review of economic and energy sector implications of adopting global climate change policies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novak, M.H.

1997-12-31

This paper summarizes a number of studies examining potential economic impacts of global climate change policies. Implications for the United States as a whole, the U.S. energy sector, the U.S. economy, businesses and consumers, and world economies are considered. Impact assessments are performed of U.S. carbon emissions, carbon taxes, and carbon restrictions by comparing estimates from various organizations. The following conclusions were made from the economic studies: (1) the economic cost of carbon abatement is expensive; (2) the cost of unilateral action is very expensive with little quantifiable evidence that global emissions are reduced; (3) multilateral actions of developed countriesmore » are also very expensive, but there is quantifiable evidence of global emissions reductions; and (4) global actions have only been theoretically addressed. Paralleling these findings, the energy analyses show that the U.S. is technologically unprepared to give up fossil fuels. As a result: (1) carbon is not stabilized without a high tax, (2) stabilization of carbon is elusive, (3) technology is the only long-term answer, and (4) targeted programs may be appropriate to force technology development. 8 tabs.« less

A global probabilistic tsunami hazard assessment from earthquake sources

USGS Publications Warehouse

Davies, Gareth; Griffin, Jonathan; Lovholt, Finn; Glimsdal, Sylfest; Harbitz, Carl; Thio, Hong Kie; Lorito, Stefano; Basili, Roberto; Selva, Jacopo; Geist, Eric L.; Baptista, Maria Ana

2017-01-01

Large tsunamis occur infrequently but have the capacity to cause enormous numbers of casualties, damage to the built environment and critical infrastructure, and economic losses. A sound understanding of tsunami hazard is required to underpin management of these risks, and while tsunami hazard assessments are typically conducted at regional or local scales, globally consistent assessments are required to support international disaster risk reduction efforts, and can serve as a reference for local and regional studies. This study presents a global-scale probabilistic tsunami hazard assessment (PTHA), extending previous global-scale assessments based largely on scenario analysis. Only earthquake sources are considered, as they represent about 80% of the recorded damaging tsunami events. Globally extensive estimates of tsunami run-up height are derived at various exceedance rates, and the associated uncertainties are quantified. Epistemic uncertainties in the exceedance rates of large earthquakes often lead to large uncertainties in tsunami run-up. Deviations between modelled tsunami run-up and event observations are quantified, and found to be larger than suggested in previous studies. Accounting for these deviations in PTHA is important, as it leads to a pronounced increase in predicted tsunami run-up for a given exceedance rate.

Modeling trade-offs between plant fiber and toxins: a framework for quantifying risks perceived by foraging herbivores.

PubMed

Camp, Meghan J; Shipley, Lisa A; Johnson, Timothy R; Forbey, Jennifer Sorensen; Rachlow, Janet L; Crowell, Miranda M

2015-12-01

When selecting habitats, herbivores must weigh multiple risks, such as predation, starvation, toxicity, and thermal stress, forcing them to make fitness trade-offs. Here, we applied the method of paired comparisons (PC) to investigate how herbivores make trade-offs between habitat features that influence selection of food patches. The method of PC measures utility and the inverse of utility, relative risk, and makes trade-offs and indifferences explicit by forcing animals to make choices between two patches with different types of risks. Using a series of paired-choice experiments to titrate the equivalence curve and find the marginal rate of substitution for one risk over the other, we evaluated how toxin-tolerant (pygmy rabbit Brachylagus idahoensis) and fiber-tolerant (mountain cottontail rabbit Sylviagus nuttallii) herbivores differed in their hypothesized perceived risk of fiber and toxins in food. Pygmy rabbits were willing to consume nearly five times more of the toxin 1,8-cineole in their diets to avoid consuming higher levels of fiber than were mountain cottontails. Fiber posed a greater relative risk for pygmy rabbits than cottontails and cineole a greater risk for cottontails than pygmy rabbits. Our flexible modeling approach can be used to (1) quantify how animals evaluate and trade off multiple habitat attributes when the benefits and risks are difficult to quantify, and (2) integrate diverse risks that influence fitness and habitat selection into a single index of habitat value. This index potentially could be applied to landscapes to predict habitat selection across several scales.

Inter-species protein trafficking endows dodder (Cuscuta pentagona) with a host-specific herbicide-tolerant trait.

PubMed

Jiang, Linjian; Qu, Feng; Li, Zhaohu; Doohan, Douglas

2013-06-01

· Besides photosynthates, dodder (Cuscuta spp.) acquires phloem-mobile proteins from host; however, whether this could mediate inter-species phenotype transfer was not demonstrated. Specifically, we test whether phosphinothricin acetyl transferase (PAT) that confers host plant glufosinate herbicide tolerance traffics and functions inter-specifically. · Dodder tendrils excised from hosts can grow in vitro for weeks or resume in vivo by parasitizing new hosts. The level of PAT in in vivo and in vitro dodder tendrils was quantified by enzyme-linked immunosorbent assay. The glufosinate sensitivity was examined by dipping the distal end of in vivo and in vitro tendrils, growing on or excised from LibertyLink (LL; PAT-transgenic and glufosinate tolerant) and conventional (CN; glufosinate sensitive) soybean hosts, into glufosinate solutions for 5 s. After in vitro tendrils excised from LL hosts reparasitized new CN and LL hosts, the PAT level and the glufosinate sensitivity were also examined. · When growing on LL host, dodder tolerated glufosinate and contained PAT at a level of 0.3% of that encountered in LL soybean leaf. After PAT was largely degraded in dodders, they became glufosinate sensitive. PAT mRNA was not detected by reverse transcription PCR in dodders. · In conclusion, the results indicated that PAT inter-species trafficking confers dodder glufosinate tolerance. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Bee genera, diversity and abundance in genetically modified canola fields.

PubMed

O'Brien, Colton; Arathi, H S

2018-01-02

Intensive agricultural practices resulting in large scale habitat loss ranks as the top contributing factors in the global bee decline. Growing Genetically Modified Herbicide Tolerant (GMHT) crops as large monocultures has resulted extensive applications of herbicides leading to the degradation of natural habitats surrounding farmlands. Herbicide tolerance trait is beneficial for crops such as Canola (Brassica napus) that are extremely vulnerable to weed competition. While the trait in itself does not harm pollinators, growing genetically modified herbicide tolerant cultivars indirectly contributes towards pollinator declines through habitat loss. Canola, a mass-flowering crop is highly attractive to bee pollinators and the extensive adoption of the herbicide tolerant trait has led to depletion of non-crop floral resources. Extensive use of herbicide in and near fields with herbicide tolerant cultivars systematically eliminates semi-natural habitats around agricultural fields which consist of non-crop flowering plants. Planting pollinator strips provides floral resources for bees after crop flowering. We document the bee genera in canola and the adjoining pollinator strip. The overlap in bee genera reinforces the importance of pollinator habitats in agricultural landscape.

Tolerance allocation for an electronic system using neural network/Monte Carlo approach

NASA Astrophysics Data System (ADS)

Al-Mohammed, Mohammed; Esteve, Daniel; Boucher, Jaque

2001-12-01

The intense global competition to produce quality products at a low cost has led many industrial nations to consider tolerances as a key factor to bring about cost as well as to remain competitive. In actually, Tolerance allocation stays widely applied on the Mechanic System. It is known that to study the tolerances in an electronic domain, Monte-Carlo method well be used. But the later method spends a long time. This paper reviews several methods (Worst-case, Statistical Method, Least Cost Allocation by Optimization methods) that can be used for treating the tolerancing problem for an Electronic System and explains their advantages and their limitations. Then, it proposes an efficient method based on the Neural Networks associated with Monte-Carlo method as basis data. The network is trained using the Error Back Propagation Algorithm to predict the individual part tolerances, minimizing the total cost of the system by a method of optimization. This proposed approach has been applied on Small-Signal Amplifier Circuit as an example. This method can be easily extended to a complex system of n-components.

Metabolic depression and the evolution of hypoxia tolerance in threespine stickleback, Gasterosteus aculeatus.

PubMed

Regan, Matthew D; Gill, Ivan S; Richards, Jeffrey G

2017-11-01

Anthropogenic increases in global temperature and agricultural runoff are increasing the prevalence of aquatic hypoxia throughout the world. We investigated the potential for a relatively rapid evolution of hypoxia tolerance using two isolated (for less than 11 000 years) populations of threespine stickleback: one from a lake that experiences long-term hypoxia (Alta Lake, British Columbia) and one from a lake that does not (Trout Lake, British Columbia). Loss-of-equilibrium (LOE) experiments revealed that the Alta Lake stickleback were significantly more tolerant of hypoxia than the Trout Lake stickleback, and calorimetry experiments revealed that the enhanced tolerance of Alta Lake stickleback may be associated with their ability to depress metabolic rate (as indicated by metabolic heat production) by 33% in hypoxia. The two populations showed little variation in their capacities for O 2 extraction and anaerobic metabolism. These results reveal that intraspecific variation in hypoxia tolerance can develop over relatively short geological timescales, as can metabolic rate depression, a complex biochemical response that may be favoured in long-term hypoxic environments. © 2017 The Author(s).

Species-specific photorespiratory rate, drought tolerance and isoprene emission rate in plants.

PubMed

Dani, K G Srikanta; Jamie, Ian M; Prentice, I Colin; Atwell, Brian J

2015-01-01

The effect of drought on plant isoprene emission varies tremendously across species and environments. It was recently shown that an increased ratio of photosynthetic electron transport rate (ETR) to net carbon assimilation rate (NAR) consistently supported increased emission under drought. In this commentary, we highlight some of the physiological aspects of drought tolerance that are central to the observed variability. We briefly discuss some of the issues that must be addressed in order to refine our understanding of plant isoprene emission response to drought and increasing global temperature.

FFA2 Contribution to Gestational Glucose Tolerance Is Not Disrupted by Antibiotics.

PubMed

Fuller, Miles; Li, Xiaoran; Fisch, Robert; Bughara, Moneb; Wicksteed, Barton; Kovatcheva-Datchary, Petia; Layden, Brian T

2016-01-01

During the insulin resistant phase of pregnancy, the mRNA expression of free fatty acid 2 receptor (Ffar2) is upregulated and as we recently reported, this receptor contributes to insulin secretion and pancreatic beta cell mass expansion in order to maintain normal glucose homeostasis during pregnancy. As impaired gestational glucose levels can affect metabolic health of offspring, we aimed to explore the role of maternal Ffar2 expression during pregnancy on the metabolic health of offspring and also the effects of antibiotics, which have been shown to disrupt gut microbiota fermentative activity (the source of the FFA2 ligands) on gestational glucose homeostasis. We found that maternal Ffar2 expression and impaired glucose tolerance during pregnancy had no effect on the growth rates, ad lib glucose and glucose tolerance in the offspring between 3 and 6 weeks of age. To disrupt short chain fatty acid production, we chronically treated WT mice and Ffar2-/- mice with broad range antibiotics and further compared their glucose tolerance prior to pregnancy and at gestational day 15, and also quantified cecum and plasma SCFAs. We found that during pregnancy antibiotic treatment reduced the levels of SCFAs in the cecum of the mice, but resulted in elevated levels of plasma SCFAs and altered concentrations of individual SCFAs. Along with these changes, gestational glucose tolerance in WT mice, but not Ffar2-/- mice improved while on antibiotics. Additional data showed that gestational glucose tolerance worsened in Ffar2-/- mice during a second pregnancy. Together, these results indicate that antibiotic treatment alone is inadequate to deplete plasma SCFA concentrations, and that modulation of gut microbiota by antibiotics does not disrupt the contribution of FFA2 to gestational glucose tolerance.

Identification of aerenchyma formation-related QTL in barley that can be effective in breeding for waterlogging tolerance.

PubMed

Zhang, Xuechen; Zhou, Gaofeng; Shabala, Sergey; Koutoulis, Anthony; Shabala, Lana; Johnson, Peter; Li, Chengdao; Zhou, Meixue

2016-06-01

Aerenchyma formation after 7 days of waterlogging in commercial potting mixture can be a reliable, fast, and widely utilized approach for the selection of waterlogging tolerant barley genotypes. One major QTL for aerenchyma formation after 7 days of waterlogging treatment was identified and the newly developed markers explained 44 % of the phenotypic variance. This QTL can now be effectively used in barley breeding programs. Waterlogging is one of the important limiting conditions for crop yield and productivity. The main feature of waterlogged soils is oxygen deprivation, due to slow gas diffusion in water. Decreased oxygen content in waterlogged soils leads to the oxygen deficiency in plant tissues, resulting in reduced energy availability for plants. Rapidly induced aerenchyma formation is critical to maintaining adequate oxygen supply and overall waterlogging tolerance in barley. In this study, we have proved that quantifying aerenchyma formation after 7 days of waterlogging in commercial potting mixture can be a reliable, fast, and widely utilised approach for the selection of waterlogging tolerant barley genotypes, which is supported by measurements of redox potential (an indicator of anaerobic conditions). This protocol was also used to identify quantitative trait loci (QTL) in a doubled haploid population of barley from the cross between Yerong (tolerant) and Franklin (sensitive) genotypes. The QTL for aerenchyma formation and root porosity were at the same location as the waterlogging tolerance QTL. Seven new markers were developed and added onto this region on chromosome 4H. One major QTL for aerenchyma formation after 7 days waterlogging treatment explained 44.0 % of the phenotypic variance. This successful QTL for aerenchyma formation can be effectively used in the marker assisted selection to improve waterlogging tolerance in barley.

Theoretical investigation on radiation tolerance of {{\\boldsymbol{M}}}_{{\\boldsymbol{n}}+1}{{\\boldsymbol{AX}}}_{{\\boldsymbol{n}}} phases

NASA Astrophysics Data System (ADS)

Yin, Ke-Di; Zhang, Xi-Tong; Huang, Qing; Xue, Jian-Ming

2017-06-01

Ternary {M}n+1{{AX}}n phases with layered hexagonal structures, as candidate materials used for next-generation nuclear reactors, have shown great potential in tolerating radiation damage due to their unique combination of ceramic and metallic properties. However, {M}n+1{{AX}}n materials behave differently in amorphization when exposed to energetic neutron and ion irradiations in experiment. We first analyze the irradiation tolerances of different {M}n+1{{AX}}n (MAX) phases in terms of electronic structure, including the density of states (DOS) and charge density map. Then a new method based on the Bader analysis with the first-principle calculation is used to estimate the stabilities of MAX phases under irradiation. Our calculations show that the substitution of Cr/V/Ta/Nb by Ti and Si/Ge/Ga by Al can increase the ionicities of the bonds, thus strengthening the radiation tolerance. It is also shown that there is no obvious difference in radiation tolerance between {M}n+1A{{{C}}}n and {M}n+1A{{{N}}}n due to the similar charge transfer values of C and N atoms. In addition, the improved radiation tolerance from Ti3AlC2 to Ti2AlC (Ti3AlC2 and Ti2AlC have the same chemical elements), can be understood in terms of the increased Al/TiC layer ratio. Criteria based on the quantified charge transfer can be further used to explore other {M}n+1{{AX}}n phases with respect to their radiation tolerance, playing a critical role in choosing appropriate MAX phases before they are subjected to irradiation in experimental test for future nuclear reactors. Project supported by the National Natural Science Foundation of China (Grant Nos. 91226202 and 91426304).

Stress tolerance of soil fungal communities from native Atlantic forests, reforestations, and a sand mining degraded area.

PubMed

Ferreira, Paulo C; Pupin, Breno; Rangel, Drauzio E N

2018-06-01

Microorganisms are essential to the functionality of the soil, particularly in organic matter decomposition and nutrient cycling, which regulate plant productivity and shape the soil structure. However, biotic and abiotic stresses greatly disrupt soil fungal communities and, thereby, disturb the ecosystem. This study quantified seasonal tolerances to UV-B radiation and heat of fungal communities, which could be cultured, found in soil from two native Atlantic forest fragments called F1 and F2, five reforested areas (RA) planted in 1994, 1997, 2004, 2007, and 2009 with native species of the Atlantic forest, and one sand mining degraded soil (SMDS). The cold activity of the soil fungal communities (FC) from the eight different areas was also studied. Higher tolerance to UV-B radiation and heat was found in the FC from the SMDS and the 2009RA, where the incidence of heat and UV radiation from sun was more intense, which caused selection for fungal taxa that were more UV-B and heat tolerant in those areas. Conversely, the FC from the native forests and older reforested sites were very susceptible to heat and UV-B radiation. The cold activity of the soil FC from different areas of the study showed an erratic pattern of responses among the sampling sites. Little difference in tolerance to UV-B radiation and heat was found among the FC of soil samples collected in different seasons; in general soil FC collected in winter were less tolerant to UV-B radiation, but not for heat. In conclusion, FC from SMDS soil that receive intense heat and UV radiation, as well as with low nutrient availability, were more tolerant to both UV-B radiation and heat. Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

The use of infrared thermal imaging as a non-destructive screening tool for identifying drought-tolerant lentil genotypes.

PubMed

Biju, Sajitha; Fuentes, Sigfredo; Gupta, Dorin

2018-06-01

Lentil (Lens culinaris, Medik.) is an important legume crop, which often experience drought stress especially at the flowering and grain filling phenological stages. The availability of efficient and robust screening tools based on relevant non-destructive quantifiable traits would facilitate research on crop improvement for drought tolerance. The objective of this study was to evaluate the drought tolerance of 37 lentil genotypes using infrared thermal imaging (IRTI), drought tolerance parameters and multivariate data analysis. Potted plants were kept in a completely randomized design in a growth chamber with five replicates. Plants were subjected to three different drought treatments: 100, 50 and 20% of field capacity at the onset of reproductive period. The relative drought stress tolerance was determined based on a set of morpho-physiological parameters including non-destructive measures based on IRTI, such as: canopy temperature (Tc), canopy temperature depression (CTD) and crop water stress index (CWSI) during the growing period and destructive measures at harvest, such as: dry root-shoot ratio (RS ratio), relative water content (RWC) and harvest index (HI). The drought tolerance indices used were drought susceptibility index (DSI) and drought tolerance efficiency (DTE). Results showed that drought stress treatments significantly reduced the RWC, HI, CTD and DSI, whereas, the values of Tc, CWSI, RS ratio and DTE significantly increased for all the genotypes. The cluster analysis from morpho-physiological parameters clustered genotypes in three distinctive groups as per the level of drought stress tolerance. The genotypes with higher values of RS ratio, RWC, HI, DTE and CTD and lower values of DSI, Tc and CWSI were identified as drought-tolerant genotypes. Based on this preliminary screening, the genotypes Digger, Cumra, Indianhead, ILL 5588, ILL 6002 and ILL 5582 were identified as promising drought-tolerant genotypes. It can be concluded that the IRTI analysis is a high-throughput constructive screening tool along with RS ratio, RWC, HI and other drought tolerance indices to define the drought stress tolerance variability within lentil plants. These results provide a foundation for future research directed at identifying powerful drought assessment traits using rapid and non-destructive techniques, such as IRTI along with the yield traits, and understanding the biochemical and molecular mechanisms underlying lentil tolerance to drought stress. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Global rainfall erosivity assessment based on high-temporal resolution rainfall records

USDA-ARS?s Scientific Manuscript database

Rainfall erosivity quantifies the climatic effect on water erosion. In the framework of the Universal Soil Loss Equation, rainfall erosivity, also known as the R-factor, is defined as the mean annual sum of event erosivity values. For a new global soil erosion assessment, also in the broad context...

Predicting coral bleaching in response to environmental stressors using 8 years of global-scale data.

PubMed

Yee, Susan Harrell; Barron, Mace G

2010-02-01

Coral reefs have experienced extensive mortality over the past few decades as a result of temperature-induced mass bleaching events. There is an increasing realization that other environmental factors, including water mixing, solar radiation, water depth, and water clarity, interact with temperature to either exacerbate bleaching or protect coral from mass bleaching. The relative contribution of these factors to variability in mass bleaching at a global scale has not been quantified, but can provide insights when making large-scale predictions of mass bleaching events. Using data from 708 bleaching surveys across the globe, a framework was developed to predict the probability of moderate or severe bleaching as a function of key environmental variables derived from global-scale remote-sensing data. The ability of models to explain spatial and temporal variability in mass bleaching events was quantified. Results indicated approximately 20% improved accuracy of predictions of bleaching when solar radiation and water mixing, in addition to elevated temperature, were incorporated into models, but predictive accuracy was variable among regions. Results provide insights into the effects of environmental parameters on bleaching at a global scale.

Hydroclimatic Controls over Global Variations in Phenology and Carbon Flux

NASA Technical Reports Server (NTRS)

Koster, Randal; Walker, G.; Thornton, Patti; Collatz, G. J.

2012-01-01

The connection between phenological and hydroclimatological variations are quantified through joint analyses of global NDVI, LAI, and precipitation datasets. The global distributions of both NDVI and LAI in the warm season are strongly controlled by three quantities: mean annual precipitation, the standard deviation of annual precipitation, and Budyko's index of dryness. Upon demonstrating that these same basic (if biased) relationships are produced by a dynamic vegetation model (the dynamic vegetation and carbon storage components of the NCAR Community Land Model version 4 combined with the water and energy balance framework of the Catchment Land Surface Model of the NASA Global Modeling and Assimilation Office), we use the model to perform a sensitivity study focusing on how phenology and carbon flux might respond to climatic change. The offline (decoupled from the atmosphere) simulations show us, for example, where on the globe a given small increment in precipitation mean or variability would have the greatest impact on carbon uptake. The analysis framework allows us in addition to quantify the degree to which climatic biases in a free-running GCM are manifested as biases in simulated phenology.

Hydroclimatic Controls over Global Variations in Phenology and Carbon Flux

NASA Astrophysics Data System (ADS)

Koster, R. D.; Walker, G.; Thornton, P. E.; Collatz, G. J.

2012-12-01

The connection between phenological and hydroclimatological variations are quantified through joint analyses of global NDVI, LAI, and precipitation datasets. The global distributions of both NDVI and LAI in the warm season are strongly controlled by three quantities: mean annual precipitation, the standard deviation of annual precipitation, and Budyko's index of dryness. Upon demonstrating that these same basic (if somewhat biased) relationships are produced by a dynamic vegetation model (the dynamic vegetation and carbon storage components of the NCAR Community Land Model version 4 combined with the water and energy balance framework of the Catchment Land Surface Model of the NASA Global Modeling and Assimilation Office), we use the model to perform a sensitivity study focusing on how phenology and carbon flux might respond to climatic change. The offline (decoupled from the atmosphere) simulations show us, for example, where on the globe a given small increment in precipitation mean or variability would have the greatest impact on carbon uptake. The analysis framework allows us in addition to quantify the degree to which climatic biases in a free-running GCM are manifested as biases in simulated phenology.

Plant Distribution Data Show Broader Climatic Limits than Expert-Based Climatic Tolerance Estimates

PubMed Central

Curtis, Caroline A.; Bradley, Bethany A.

2016-01-01

Background Although increasingly sophisticated environmental measures are being applied to species distributions models, the focus remains on using climatic data to provide estimates of habitat suitability. Climatic tolerance estimates based on expert knowledge are available for a wide range of plants via the USDA PLANTS database. We aim to test how climatic tolerance inferred from plant distribution records relates to tolerance estimated by experts. Further, we use this information to identify circumstances when species distributions are more likely to approximate climatic tolerance. Methods We compiled expert knowledge estimates of minimum and maximum precipitation and minimum temperature tolerance for over 1800 conservation plant species from the ‘plant characteristics’ information in the USDA PLANTS database. We derived climatic tolerance from distribution data downloaded from the Global Biodiversity and Information Facility (GBIF) and corresponding climate from WorldClim. We compared expert-derived climatic tolerance to empirical estimates to find the difference between their inferred climate niches (ΔCN), and tested whether ΔCN was influenced by growth form or range size. Results Climate niches calculated from distribution data were significantly broader than expert-based tolerance estimates (Mann-Whitney p values << 0.001). The average plant could tolerate 24 mm lower minimum precipitation, 14 mm higher maximum precipitation, and 7° C lower minimum temperatures based on distribution data relative to expert-based tolerance estimates. Species with larger ranges had greater ΔCN for minimum precipitation and minimum temperature. For maximum precipitation and minimum temperature, forbs and grasses tended to have larger ΔCN while grasses and trees had larger ΔCN for minimum precipitation. Conclusion Our results show that distribution data are consistently broader than USDA PLANTS experts’ knowledge and likely provide more robust estimates of climatic tolerance, especially for widespread forbs and grasses. These findings suggest that widely available expert-based climatic tolerance estimates underrepresent species’ fundamental niche and likely fail to capture the realized niche. PMID:27870859

Quantifying Water Stress Using Total Water Volumes and GRACE

NASA Astrophysics Data System (ADS)

Richey, A. S.; Famiglietti, J. S.; Druffel-Rodriguez, R.

2011-12-01

Water will follow oil as the next critical resource leading to unrest and uprisings globally. To better manage this threat, an improved understanding of the distribution of water stress is required today. This study builds upon previous efforts to characterize water stress by improving both the quantification of human water use and the definition of water availability. Current statistics on human water use are often outdated or inaccurately reported nationally, especially for groundwater. This study improves these estimates by defining human water use in two ways. First, we use NASA's Gravity Recovery and Climate Experiment (GRACE) to isolate the anthropogenic signal in water storage anomalies, which we equate to water use. Second, we quantify an ideal water demand by using average water requirements for the domestic, industrial, and agricultural water use sectors. Water availability has traditionally been limited to "renewable" water, which ignores large, stored water sources that humans use. We compare water stress estimates derived using either renewable water or the total volume of water globally. We use the best-available data to quantify total aquifer and surface water volumes, as compared to groundwater recharge and surface water runoff from land-surface models. The work presented here should provide a more realistic image of water stress by explicitly quantifying groundwater, defining water availability as total water supply, and using GRACE to more accurately quantify water use.

Recent Advances in Utilizing Transcription Factors to Improve Plant Abiotic Stress Tolerance by Transgenic Technology

PubMed Central

Wang, Hongyan; Wang, Honglei; Shao, Hongbo; Tang, Xiaoli

2016-01-01

Agricultural production and quality are adversely affected by various abiotic stresses worldwide and this will be exacerbated by the deterioration of global climate. To feed a growing world population, it is very urgent to breed stress-tolerant crops with higher yields and improved qualities against multiple environmental stresses. Since conventional breeding approaches had marginal success due to the complexity of stress tolerance traits, the transgenic approach is now being popularly used to breed stress-tolerant crops. So identifying and characterizing the critical genes involved in plant stress responses is an essential prerequisite for engineering stress-tolerant crops. Far beyond the manipulation of single functional gene, engineering certain regulatory genes has emerged as an effective strategy now for controlling the expression of many stress-responsive genes. Transcription factors (TFs) are good candidates for genetic engineering to breed stress-tolerant crop because of their role as master regulators of many stress-responsive genes. Many TFs belonging to families AP2/EREBP, MYB, WRKY, NAC, bZIP have been found to be involved in various abiotic stresses and some TF genes have also been engineered to improve stress tolerance in model and crop plants. In this review, we take five large families of TFs as examples and review the recent progress of TFs involved in plant abiotic stress responses and their potential utilization to improve multiple stress tolerance of crops in the field conditions. PMID:26904044

Xanthos

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-05-30

Xanthos is a Python package designed to quantify and analyze global water availability in history and in future at 0.5° × 0.5° spatial resolution and a monthly time step under a changing climate. Its performance was also tested through real applications. It is open-source, extendable and convenient to researchers who work on long-term climate data for studies of global water supply, and Global Change Assessment Model (GCAM). This package integrates inherent global gridded data maps, I/O modules, Water-Balance Model modules and diagnostics modules by user-defined configuration.

Transgenerational Adaptation of Arabidopsis to Stress Requires DNA Methylation and the Function of Dicer-Like Proteins

PubMed Central

Boyko, Alex; Blevins, Todd; Yao, Youli; Golubov, Andrey; Bilichak, Andriy; Ilnytskyy, Yaroslav; Hollander, Jens; Meins, Frederick; Kovalchuk, Igor

2010-01-01

Epigenetic states and certain environmental responses in mammals and seed plants can persist in the next sexual generation. These transgenerational effects have potential adaptative significance as well as medical and agronomic ramifications. Recent evidence suggests that some abiotic and biotic stress responses of plants are transgenerational. For example, viral infection of tobacco plants and exposure of Arabidopsis thaliana plants to UVC and flagellin can induce transgenerational increases in homologous recombination frequency (HRF). Here we show that exposure of Arabidopsis plants to stresses, including salt, UVC, cold, heat and flood, resulted in a higher HRF, increased global genome methylation, and higher tolerance to stress in the untreated progeny. This transgenerational effect did not, however, persist in successive generations. Treatment of the progeny of stressed plants with 5-azacytidine was shown to decrease global genomic methylation and enhance stress tolerance. Dicer-like (DCL) 2 and DCL3 encode Dicer activities important for small RNA-dependent gene silencing. Stress-induced HRF and DNA methylation were impaired in dcl2 and dcl3 deficiency mutants, while in dcl2 mutants, only stress-induced stress tolerance was impaired. Our results are consistent with the hypothesis that stress-induced transgenerational responses in Arabidopsis depend on altered DNA methylation and smRNA silencing pathways. PMID:20209086

Molecular and Evolutionary Mechanisms of Cuticular Wax for Plant Drought Tolerance.

PubMed

Xue, Dawei; Zhang, Xiaoqin; Lu, Xueli; Chen, Guang; Chen, Zhong-Hua

2017-01-01

Cuticular wax, the first protective layer of above ground tissues of many plant species, is a key evolutionary innovation in plants. Cuticular wax safeguards the evolution from certain green algae to flowering plants and the diversification of plant taxa during the eras of dry and adverse terrestrial living conditions and global climate changes. Cuticular wax plays significant roles in plant abiotic and biotic stress tolerance and has been implicated in defense mechanisms against excessive ultraviolet radiation, high temperature, bacterial and fungal pathogens, insects, high salinity, and low temperature. Drought, a major type of abiotic stress, poses huge threats to global food security and health of terrestrial ecosystem by limiting plant growth and crop productivity. The composition, biochemistry, structure, biosynthesis, and transport of plant cuticular wax have been reviewed extensively. However, the molecular and evolutionary mechanisms of cuticular wax in plants in response to drought stress are still lacking. In this review, we focus on potential mechanisms, from evolutionary, molecular, and physiological aspects, that control cuticular wax and its roles in plant drought tolerance. We also raise key research questions and propose important directions to be resolved in the future, leading to potential applications of cuticular wax for water use efficiency in agricultural and environmental sustainability.

Quantifying the topography of the intrinsic energy landscape of flexible biomolecular recognition

PubMed Central

Chu, Xiakun; Gan, Linfeng; Wang, Erkang; Wang, Jin

2013-01-01

Biomolecular functions are determined by their interactions with other molecules. Biomolecular recognition is often flexible and associated with large conformational changes involving both binding and folding. However, the global and physical understanding for the process is still challenging. Here, we quantified the intrinsic energy landscapes of flexible biomolecular recognition in terms of binding–folding dynamics for 15 homodimers by exploring the underlying density of states, using a structure-based model both with and without considering energetic roughness. By quantifying three individual effective intrinsic energy landscapes (one for interfacial binding, two for monomeric folding), the association mechanisms for flexible recognition of 15 homodimers can be classified into two-state cooperative “coupled binding–folding” and three-state noncooperative “folding prior to binding” scenarios. We found that the association mechanism of flexible biomolecular recognition relies on the interplay between the underlying effective intrinsic binding and folding energy landscapes. By quantifying the whole global intrinsic binding–folding energy landscapes, we found strong correlations between the landscape topography measure Λ (dimensionless ratio of energy gap versus roughness modulated by the configurational entropy) and the ratio of the thermodynamic stable temperature versus trapping temperature, as well as between Λ and binding kinetics. Therefore, the global energy landscape topography determines the binding–folding thermodynamics and kinetics, crucial for the feasibility and efficiency of realizing biomolecular function. We also found “U-shape” temperature-dependent kinetic behavior and a dynamical cross-over temperature for dividing exponential and nonexponential kinetics for two-state homodimers. Our study provides a unique way to bridge the gap between theory and experiments. PMID:23754431

User’s Guide and Metadata for the PICES Nonindigenous Species Information System

EPA Science Inventory

The database, the "PICES Nonindigenous Species Information System", was constucted to synthesize the global distributions, environmental tolerances, and natural history attributes of the nonindigenous species in the North Pacific and Hawaii. The User's Guide provides th...

Secure satellite communication using multi-photon tolerant quantum communication protocol

NASA Astrophysics Data System (ADS)

Darunkar, Bhagyashri; Punekar, Nikhil; Verma, Pramode K.

2015-09-01

This paper proposes and analyzes the potential of a multi-photon tolerant quantum communication protocol to secure satellite communication. For securing satellite communication, quantum cryptography is the only known unconditionally secure method. A number of recent experiments have shown feasibility of satellite-aided global quantum key distribution (QKD) using different methods such as: Use of entangled photon pairs, decoy state methods, and entanglement swapping. The use of single photon in these methods restricts the distance and speed over which quantum cryptography can be applied. Contemporary quantum cryptography protocols like the BB84 and its variants suffer from the limitation of reaching the distances of only Low Earth Orbit (LEO) at the data rates of few kilobits per second. This makes it impossible to develop a general satellite-based secure global communication network using the existing protocols. The method proposed in this paper allows secure communication at the heights of the Medium Earth Orbit (MEO) and Geosynchronous Earth Orbit (GEO) satellites. The benefits of the proposed method are two-fold: First it enables the realization of a secure global communication network based on satellites and second it provides unconditional security for satellite networks at GEO heights. The multi-photon approach discussed in this paper ameliorates the distance and speed issues associated with quantum cryptography through the use of contemporary laser communication (lasercom) devices. This approach can be seen as a step ahead towards global quantum communication.

Aluminum Toxicity-Induced Alterations of Leaf Proteome in Two Citrus Species Differing in Aluminum Tolerance.

PubMed

Li, Huan; Yang, Lin-Tong; Qi, Yi-Ping; Guo, Peng; Lu, Yi-Bin; Chen, Li-Song

2016-07-21

Seedlings of aluminum-tolerant 'Xuegan' (Citrus sinensis) and Al-intolerant 'sour pummelo' (Citrus grandis) were fertigated for 18 weeks with nutrient solution containing 0 and 1.2 mM AlCl₃·6H₂O. Al toxicity-induced inhibition of photosynthesis and the decrease of total soluble protein only occurred in C. grandis leaves, demonstrating that C. sinensis had higher Al tolerance than C. grandis. Using isobaric tags for relative and absolute quantification (iTRAQ), we obtained more Al toxicity-responsive proteins from C. sinensis than from C. grandis leaves, which might be responsible for the higher Al tolerance of C. sinensis. The following aspects might contribute to the Al tolerance of C. sinensis: (a) better maintenance of photosynthesis and energy balance via inducing photosynthesis and energy-related proteins; (b) less increased requirement for the detoxification of reactive oxygen species and other toxic compounds, such as aldehydes, and great improvement of the total ability of detoxification; and (c) upregulation of low-phosphorus-responsive proteins. Al toxicity-responsive proteins related to RNA regulation, protein metabolism, cellular transport and signal transduction might also play key roles in the higher Al tolerance of C. sinensis. We present the global picture of Al toxicity-induced alterations of protein profiles in citrus leaves, and identify some new Al toxicity-responsive proteins related to various biological processes. Our results provide some novel clues about plant Al tolerance.

Tempo and mode of the multiple origins of salinity tolerance in a water beetle lineage.

PubMed

Arribas, Paula; Andújar, Carmelo; Abellán, Pedro; Velasco, Josefa; Millán, Andrés; Ribera, Ignacio

2014-02-01

Salinity is one of the most important drivers of the distribution, abundance and diversity of organisms. Previous studies on the evolution of saline tolerance have been mainly centred on marine and terrestrial organisms, while lineages inhabiting inland waters remain largely unexplored. This is despite the fact that these systems include a much broader range of salinities, going from freshwater to more than six times the salinity of the sea (i.e. >200 g/L). Here, we study the pattern and timing of the evolution of the tolerance to salinity in an inland aquatic lineage of water beetles (Enochrus species of the subgenus Lumetus, family Hydrophilidae), with the general aim of understanding the mechanisms by which it was achieved. Using a time-calibrated phylogeny built from five mitochondrial and two nuclear genes and information about the salinity tolerance and geographical distribution of the species, we found that salinity tolerance appeared multiple times associated with periods of global aridification. We found evidence of some accelerated transitions from freshwater directly to high salinities, as reconstructed with extant lineages. This, together with the strong positive correlation found between salinity tolerance and aridity of the habitats in which species are found, suggests that tolerance to salinity may be based on a co-opted mechanism developed originally for drought resistance. © 2013 John Wiley & Sons Ltd.

Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima” and “Cucurbita moschata”) and Their Interspecific Inbred Line “Maxchata”

PubMed Central

Ara, Neelam; Nakkanong, Korakot; Lv, Wenhui; Yang, Jinghua; Hu, Zhongyuan; Zhang, Mingfang

2013-01-01

The elucidation of heat tolerance mechanisms is required to combat the challenges of global warming. This study aimed to determine the antioxidant enzyme responses to heat stress, at the enzymatic activity and gene expression levels, and to investigate the antioxidative alterations associated with heat tolerance in the stems and roots of squashes using three genotypes differing in heat tolerance. Plants of heat-tolerant “C. moschata”, thermolabile “C. maxima” and moderately heat-tolerant interspecific inbred line “Maxchata” genotypes were exposed to moderate (37 °C) and severe (42 °C) heat shocks. “C. moschata” exhibited comparatively little oxidative damage, with the lowest hydrogen peroxide (H2O2), superoxide (O2−) and malondialdehyde (MDA) contents in the roots compared to stems, followed by “Maxchata”. The enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) were found to be increased with heat stress in tolerant genotypes. The significant inductions of FeSOD, MnSOD, APX2, CAT1 and CAT3 isoforms in tolerant genotypes suggested their participation in heat tolerance. The differential isoform patterns of SOD, APX and CAT between stems and roots also indicated their tissue specificity. Furthermore, despite the sequence similarity of the studied antioxidant genes among “C. maxima” and “Maxchata”, most of these genes were highly induced under heat stress in “Maxchata”, which contributed to its heat tolerance. This phenomenon also indicated the involvement of other unknown genetic and/or epigenetic factors in controlling the expression of these antioxidant genes in squashes, which demands further exploration. PMID:24336062

The relationship between maximum tolerated light intensity and photoprotective energy dissipation in the photosynthetic antenna: chloroplast gains and losses

PubMed Central

Ruban, Alexander V.; Belgio, Erica

2014-01-01

The principle of quantifying the efficiency of protection of photosystem II (PSII) reaction centres against photoinhibition by non-photochemical energy dissipation (NPQ) has been recently introduced by Ruban & Murchie (2012 Biochim. Biophys. Acta 1817, 977–982 (doi:10.1016/j.bbabio.2012.03.026)). This is based upon the assessment of two key parameters: (i) the relationship between the PSII yield and NPQ, and (ii) the fraction of intact PSII reaction centres in the dark after illumination. In this paper, we have quantified the relationship between the amplitude of NPQ and the light intensity at which all PSII reaction centres remain intact for plants with different levels of PsbS protein, known to play a key role in the process. It was found that the same, nearly linear, relationship exists between the levels of the protective NPQ component (pNPQ) and the tolerated light intensity in all types of studied plants. This approach allowed for the quantification of the maximum tolerated light intensity, the light intensity at which all plant leaves become photoinhibited, the fraction of (most likely) unnecessary or ‘wasteful’ NPQ, and the fraction of photoinhibited PSII reaction centres under conditions of prolonged illumination by full sunlight. It was concluded that the governing factors in the photoprotection of PSII are the level and rate of protective pNPQ formation, which are often in discord with the amplitude of the conventional measure of photoprotection, the quickly reversible NPQ component, qE. Hence, we recommend pNPQ as a more informative and less ambiguous parameter than qE, as it reflects the effectiveness and limitations of the major photoprotective process of the photosynthetic membrane. PMID:24591709

Synthesis of [ 18F]arenes via the copper-mediated [ 18F]fluorination of boronic acids

DOE PAGES

Mossine, Andrew V.; Brooks, Allen F.; Makaravage, Katarina J.; ...

2015-11-14

Here, a copper-mediated radiofluorination of aryl- and vinylboronic acids with K 18F is described. This method exhibits high functional group tolerance and is effective for the radiofluorination of a range of electron-deficient, -neutral, and -rich aryl-, heteroaryl-, and vinylboronic acids. This method has been applied to the synthesis of [ 18F]FPEB, a PET radiotracer for quantifying metabotropic glutamate 5 receptors.

Synthesis of [ 18F]arenes via the copper-mediated [ 18F]fluorination of boronic acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mossine, Andrew V.; Brooks, Allen F.; Makaravage, Katarina J.

Here, a copper-mediated radiofluorination of aryl- and vinylboronic acids with K 18F is described. This method exhibits high functional group tolerance and is effective for the radiofluorination of a range of electron-deficient, -neutral, and -rich aryl-, heteroaryl-, and vinylboronic acids. This method has been applied to the synthesis of [ 18F]FPEB, a PET radiotracer for quantifying metabotropic glutamate 5 receptors.

Injection and injection-compression moulding replication capability for the production of polymer lab-on-a-chip with nano structures

NASA Astrophysics Data System (ADS)

Calaon, M.; Tosello, G.; Garnaes, J.; Hansen, H. N.

2017-10-01

The manufacturing precision and accuracy in the production of polymer lab-on-a-chip components with 100-130 nm deep nanochannels are evaluated using a metrological approach. Replication fidelity on corresponding process fingerprint test nanostructures over different substrates (nickel tool and polymer part) is quantified through traceable atomic force microscope measurements. Dimensions of injection moulded (IM) and injection-compression moulded (ICM) thermoplastic cyclic olefin copolymer nanofeatures are characterized depending on process parameters and four different features positions on a 30  ×  80 mm2 area. Replication capability of IM and ICM technologies are quantified and the products tolerance at the nanometre dimensional scale verified.

Induction of Multidrug Tolerance in Plasmodium falciparum by Extended Artemisinin Pressure

PubMed Central

Ménard, Sandie; Ben Haddou, Tanila; Ramadani, Arba Pramundita; Ariey, Frédéric; Iriart, Xavier; Beghain, Johann; Bouchier, Christiane; Witkowski, Benoit; Berry, Antoine; Mercereau-Puijalon, Odile

2015-01-01

Plasmodium falciparum resistance to artemisinin derivatives in Southeast Asia threatens global malaria control strategies. Whether delayed parasite clearance, which exposes larger parasite numbers to artemisinins for longer times, selects higher-grade resistance remains unexplored. We investigated whether long-lasting artemisinin pressure selects a novel multidrug-tolerance profile. Although 50% inhibitory concentrations for 10 antimalarial drugs tested were unchanged, drug-tolerant parasites showed higher recrudescence rates for endoperoxides, quinolones, and an antifolate, including partner drugs of recommended combination therapies, but remained susceptible to atovaquone. Moreover, the age range of intraerythrocytic stages able to resist artemisinin was extended to older ring forms and trophozoites. Multidrug tolerance results from drug-induced quiescence, which enables parasites to survive exposure to unrelated antimalarial drugs that inhibit a variety of metabolic pathways. This novel resistance pattern should be urgently monitored in the field because this pattern is not detected by current assays and represents a major threat to antimalarial drug policy. PMID:26401601

RNA sequencing of leaf tissues from two contrasting chickpea genotypes reveals mechanisms for drought tolerance.

PubMed

Badhan, Sapna; Kole, Pravas; Ball, Andrew; Mantri, Nitin

2018-06-13

Chickpea (Cicer arietinum L.) is the second most important winter crop which is consumed globally due to its high nutritional value. Chickpea as one of the leguminous crop is important in crop rotation with cereal crops like wheat and barley. The main constraints for chickpea production are abiotic stresses such as drought, salinity, and heat. Among these, drought is a major cause of the decline in chickpea production in worldwide. Studies conducted so far have provided a limited insight into different genetic pathways associated with drought tolerance/response. In this study, the leaf tissue from shoots apical meristem stage of drought tolerant (ICC8261) and drought sensitive (ICC283) genotypes were analysed using RNA sequencing to identify genes/pathways associated with drought tolerance/sensitivity in both genotypes. It was observed that genes related to ethylene response, MYB-related protein, xyloglucan endotransglycosylase, alkane hydroxylase MAH-like, BON-1 associated, peroxidase 3, cysteine-rich and transmembrane domain, vignain and mitochondrial uncoupling were specifically up-regulated in the tolerant genotype whereas, same genes were down-regulated in sensitive genotype. The crosstalk between the different hormones and transcriptional factors involved in drought tolerance and sensitivity in both genotypes make them great candidates for future research. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Application of a Resource Theory for Magic States to Fault-Tolerant Quantum Computing.

PubMed

Howard, Mark; Campbell, Earl

2017-03-03

Motivated by their necessity for most fault-tolerant quantum computation schemes, we formulate a resource theory for magic states. First, we show that robustness of magic is a well-behaved magic monotone that operationally quantifies the classical simulation overhead for a Gottesman-Knill-type scheme using ancillary magic states. Our framework subsequently finds immediate application in the task of synthesizing non-Clifford gates using magic states. When magic states are interspersed with Clifford gates, Pauli measurements, and stabilizer ancillas-the most general synthesis scenario-then the class of synthesizable unitaries is hard to characterize. Our techniques can place nontrivial lower bounds on the number of magic states required for implementing a given target unitary. Guided by these results, we have found new and optimal examples of such synthesis.

The limited and localized flow of fresh groundwater to the world's oceans

NASA Astrophysics Data System (ADS)

Luijendijk, E.; Gleeson, T. P.; Moosdorf, N.

2017-12-01

Submarine groundwater discharge, the flow of fresh or saline groundwater to oceans [Burnett et al., 2003], may be a significant contributor to the water and chemical budgets of the world's oceans [Taniguchi et al., 2002] potentially buffering ocean acidification with groundwater alkalinity and is arguably the most uncertain component of the global groundwater budget [Alley et al., 2002]. The fresh component of submarine groundwater discharge is critical due to its high solute and nutrient load, and has been quantified locally and but only roughly estimated globally using significant assumptions. Here we show that that fresh submarine groundwater discharge is an insignificant water contributor to global oceans (0.05% of the total input) but that the freshwater discharge may still be an important chemical and nutrient contributor especially around distinct hotspots. The first spatially-explicit, physically-based global estimate of fresh submarine groundwater discharge was derived by combining density-dependent numerical groundwater models and a geospatial analysis of global coastal watersheds to robustly simulate the partitioning of onshore and offshore groundwater discharge. Although fresh submarine groundwater discharge is an insignificant part of fresh coastal groundwater discharge, results are consistent with previous estimates of significant recirculated seawater discharging as groundwater as well as quantifying the significant near-shore terrestrial discharge, a flux that has so far been overlooked in global hydrological studies and that affects coastal water budgets, evapotranspiration and ecosystems.

Coordinated approaches to quantify long-term ecosystem dynamics in response to global change

Treesearch

Yiqi Luo; Jerry Melillo; Shuli Niu; Claus Beier; James S. Clark; Aime E.T. Classen; Eric Dividson; Jeffrey S. Dukes; R. Dave Evans; Christopher B. Field; Claudia I. Czimczik; Michael Keller; Bruce A. Kimball; Lara M. Kueppers; Richard J. Norby; Shannon L. Pelini; Elise Pendall; Edward Rastetter; Johan Six; Melinda Smith; Mark G. Tjoelker; Margaret S. Torn

2011-01-01

Many serious ecosystem consequences of climate change will take decades or even centuries to emerge. Long-term ecological responses to global change are strongly regulated by slow processes, such as changes in species composition, carbon dynamics in soil and by long-lived plants, and accumulation of nutrient capitals. Understanding and predicting these processes...

High School Students' Perceptions of How Major Global Environmental Effects Might Cause Skin Cancer.

ERIC Educational Resources Information Center

Boyes, Edward; Stanisstreet, Martin

1998-01-01

Quantifies beliefs of high school students about links between skin cancer and global environmental effects. Some students confused the action of heat rays with that of ultraviolet rays and also thought that raised temperatures are culpable. Only one in 10 held the scientifically correct model: that ozone depletion via higher penetration of…

Xanthos – A Global Hydrologic Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xinya; Vernon, Chris R.; Hejazi, Mohamad I.

Xanthos is an open-source hydrologic model, written in Python, designed to quantify and analyse global water availability. Xanthos simulates historical and future global water availability on a monthly time step at a spatial resolution of 0.5 geographic degrees. Xanthos was designed to be extensible and used by scientists that study global water supply and work with the Global Change Assessment Model (GCAM). Xanthos uses a user-defined configuration file to specify model inputs, outputs and parameters. Xanthos has been tested using actual global data sets and the model is able to provide historical observations and future estimates of renewable freshwater resourcesmore » in the form of total runoff.« less

Xanthos – A Global Hydrologic Model

DOE PAGES

Li, Xinya; Vernon, Chris R.; Hejazi, Mohamad I.; ...

2017-09-11

Xanthos is an open-source hydrologic model, written in Python, designed to quantify and analyse global water availability. Xanthos simulates historical and future global water availability on a monthly time step at a spatial resolution of 0.5 geographic degrees. Xanthos was designed to be extensible and used by scientists that study global water supply and work with the Global Change Assessment Model (GCAM). Xanthos uses a user-defined configuration file to specify model inputs, outputs and parameters. Xanthos has been tested using actual global data sets and the model is able to provide historical observations and future estimates of renewable freshwater resourcesmore » in the form of total runoff.« less

A relative quantitative Methylation-Sensitive Amplified Polymorphism (MSAP) method for the analysis of abiotic stress.

PubMed

Bednarek, Piotr T; Orłowska, Renata; Niedziela, Agnieszka

2017-04-21

We present a new methylation-sensitive amplified polymorphism (MSAP) approach for the evaluation of relative quantitative characteristics such as demethylation, de novo methylation, and preservation of methylation status of CCGG sequences, which are recognized by the isoschizomers HpaII and MspI. We applied the technique to analyze aluminum (Al)-tolerant and non-tolerant control and Al-stressed inbred triticale lines. The approach is based on detailed analysis of events affecting HpaII and MspI restriction sites in control and stressed samples, and takes advantage of molecular marker profiles generated by EcoRI/HpaII and EcoRI/MspI MSAP platforms. Five Al-tolerant and five non-tolerant triticale lines were exposed to aluminum stress using the physiologicaltest. Total genomic DNA was isolated from root tips of all tolerant and non-tolerant lines before and after Al stress following metAFLP and MSAP approaches. Based on codes reflecting events affecting cytosines within a given restriction site recognized by HpaII and MspI in control and stressed samples demethylation (DM), de novo methylation (DNM), preservation of methylated sites (MSP), and preservation of nonmethylatedsites (NMSP) were evaluated. MSAP profiles were used for Agglomerative hierarchicalclustering (AHC) based on Squared Euclidean distance and Ward's Agglomeration method whereas MSAP characteristics for ANOVA. Relative quantitative MSAP analysis revealed that both Al-tolerant and non-tolerant triticale lines subjected to Al stress underwent demethylation, with demethylation of CG predominating over CHG. The rate of de novo methylation in the CG context was ~3-fold lower than demethylation, whereas de novo methylation of CHG was observed only in Al-tolerant lines. Our relative quantitative MSAP approach, based on methylation events affecting cytosines within HpaII-MspI recognition sequences, was capable of quantifying de novo methylation, demethylation, methylation, and non-methylated status in control and stressed Al-tolerant and non-tolerant triticale inbred lines. The method could also be used to analyze methylation events affecting CG and CHG contexts, which were differentially methylated under Al stress. We cannot exclude that the methylation changes revealed among lines as well as between Al-tolerant and non-tolerant groups of lines were due to some experimental errors or that the number of lines was too small for ANOVA to prove the influence of Al stress. Nevertheless, we suspect that Al tolerance in triticale could be partly regulated by epigenetic factors acting at the level of DNA methylation. This method provides a valuable tool for studies of abiotic stresses in plants.

Resistance rather than tolerance explains survival of savannah honeybees (Apis mellifera scutellata) to infestation by the parasitic mite Varroa destructor.

PubMed

Strauss, Ursula; Dietemann, Vincent; Human, Hannelie; Crewe, Robin M; Pirk, Christian W W

2016-03-01

Varroa destructor is considered the most damaging parasite affecting honeybees (Apis mellifera L.). However, some honeybee populations such as the savannah honeybee (Apis mellifera scutellata) can survive mite infestation without treatment. It is unclear if survival is due to resistance mechanisms decreasing parasite reproduction or to tolerance mechanisms decreasing the detrimental effects of mites on the host. This study investigates both aspects by quantifying the reproductive output of V. destructor and its physiological costs at the individual host level. Costs measured were not consistently lower when compared with susceptible honeybee populations, indicating a lack of tolerance. In contrast, reproduction of V. destructor mites was distinctly lower than in susceptible populations. There was higher proportion of infertile individuals and the reproductive success of fertile mites was lower than measured to date, even in surviving populations. Our results suggest that survival of savannah honeybees is based on resistance rather than tolerance to this parasite. We identified traits that may be useful for breeding programmes aimed at increasing the survival of susceptible populations. African honeybees may have benefited from a lack of human interference, allowing natural selection to shape a population of honeybees that is more resistant to Varroa mite infestation.

More grain per drop of water: Screening rice genotype for physiological parameters of drought tolerance

NASA Astrophysics Data System (ADS)

Massanelli, J.; Meadows-McDonnell, M.; Konzelman, C.; Moon, J. B.; Kumar, A.; Thomas, J.; Pereira, A.; Naithani, K. J.

2016-12-01

Meeting agricultural water demands is becoming progressively difficult due to population growth and changes in climate. Breeding stress-resilient crops is a viable solution, as information about genetic variation and their role in stress tolerance is becoming available due to advancement in technology. In this study we screened eight diverse rice genotypes for photosynthetic capacity under greenhouse conditions. These include the Asian rice (Oryza sativa) genotypes, drought sensitive Nipponbare, and a transgenic line overexpressing the HYR gene in Nipponbare; six genotypes (Vandana, Bengal, Nagina-22, Glaberrima, Kaybonnet, Ai Chueh Ta Pai Ku) and an African rice O. glaberrima, all selected for varying levels of drought tolerance. We collected CO2 and light response curve data under well-watered and simulated drought conditions in greenhouse. From these curves we estimated photosynthesis model parameters, such as the maximum carboxylation rate (Vcmax), the maximum electron transport rate (Jmax), the maximum gross photosynthesis rate, daytime respiration (Rd), and quantum yield (f). Our results suggest that O. glaberrima and Nipponbare were the most sensitive to drought because Vcmax and Pgmax declined under drought conditions; other drought tolerant genotypes did not show significant changes in these model parameters. Our integrated approach, combining genetic information and photosynthesis modeling, shows promise to quantify drought response parameters and improve crop yield under drought stress conditions.

Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance.

PubMed

Singh, Dhananjaya P; Prabha, Ratna; Yandigeri, Mahesh S; Arora, Dilip K

2011-11-01

Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30 days. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirmation with LC-MS/MS showed consistent accumulation of phenolic acids (gallic, gentisic, caffeic, chlorogenic and ferulic acids), flavonoids (rutin and quercetin) and phytohormones (indole acetic acid and indole butyric acid) in rice leaves. Plant growth promotion (shoot, root length and biomass) was positively correlated with total protein and chlorophyll content of leaves. Enzyme activity of peroxidase and phenylalanine ammonia lyase and total phenolic content was fairly high in rice leaves inoculated with O. acuta and P. boryanum after 30 days. Differential systemic accumulation of phenylpropanoids in plant leaves led us to conclude that cyanobacterial inoculation correlates positively with plant growth promotion and stress tolerance in rice. Furthermore, the study helped in deciphering possible mechanisms underlying plant growth promotion and stress tolerance in rice following cyanobacterial inoculation and indicated the less explored avenue of cyanobacterial colonization in stress tolerance against abiotic stress.

Effect of anoxia on the electroretinogram of three anoxia-tolerant vertebrates.

PubMed

Stensløkken, Kåre-Olav; Milton, Sarah L; Lutz, Peter L; Sundin, Lena; Renshaw, Gillian M C; Stecyk, Jonathan A W; Nilsson, Göran E

2008-08-01

To survive anoxia, neural ATP levels have to be defended. Reducing electrical activity, which accounts for 50% or more of neural energy consumption, should be beneficial for anoxic survival. The retina is a hypoxia sensitive part of the central nervous system. Here, we quantify the in vivo retinal light response (electroretinogram; ERG) in three vertebrates that exhibit varying degrees of anoxia tolerance: freshwater turtle (Trachemys scripta), epaulette shark (Hemiscyllium ocellatum) and leopard frog (Rana pipiens). A virtually total suppression of ERG in anoxia, probably resulting in functional blindness, has previously been seen in the extremely anoxia-tolerant crucian carp (Carassius carassius). Surprisingly, the equally anoxia-tolerant turtle, which strongly depresses brain and whole-body metabolism during anoxia, exhibited a relatively modest anoxic reduction in ERG: the combined amplitude of turtle ERG waves was reduced by approximately 50% after 2 h. In contrast, the shark b-wave amplitude practically disappeared after 30 min of severe hypoxia, and the frog b-wave was decreased by approximately 75% after 40 min in anoxia. The specific A(1) adenosine receptor antagonist CPT significantly delayed the suppression of turtle ERG, while the hypoxic shark ERG was unaffected by the non-specific adenosine receptor antagonist aminophylline, suggesting adenosinergic involvement in turtle but not in shark.

Sensitive vs. tolerant Nitzschia palea (Kützing) W. Smith strains to atrazine: a biochemical perspective.

PubMed

Esteves, S M; Almeida, S F P; Gonçalves, S; Rimet, F; Bouchez, A; Figueira, E

2018-06-16

Organic contaminants, and herbicides in particular, represent a risk for aquatic ecosystems. The primary target of herbicides are producers, the base of food webs, but frequently they end up far from the application point affecting non-target species. Its presence can work as sub-lethal stimulus, which sort the genetic and phenotypic differences within a species. Intraspecific variation allows adaptation to changes in the environment but also to new niches due to variations in species' sensitivity and biochemical response to a certain chemical. A better understanding of these variations can lead to the development of improved strategies for ecosystem protection. This research aimed to compare a sensitive and a tolerant strain of the freshwater diatom Nitzschia palea to atrazine. Strains were exposed to three concentrations within their tolerance range, during 96 h. The activity of the antioxidant enzymes superoxide dismutase, catalase, glutathione-S-transferases and glutathione peroxidases was determined. In addition, chlorophylls a and c, carotenoids, reduced glutathione, proteins and lipid peroxidation were quantified. Both strains displayed different strategies to deal with atrazine toxicity: while the sensitive strain decreased the oxidative stress, increasing the activity of antioxidant enzymes such as superoxide dismutase, the tolerant strain invested in conjugation pathways and carotenoids' maintenance.

The influence of land-use change and landscape dynamics on the climate system: relevance to climate-change policy beyond the radiative effect of greenhouse gases.

PubMed

Pielke, Roger A; Marland, Gregg; Betts, Richard A; Chase, Thomas N; Eastman, Joseph L; Niles, John O; Niyogi, Dev Dutta S; Running, Steven W

2002-08-15

Our paper documents that land-use change impacts regional and global climate through the surface-energy budget, as well as through the carbon cycle. The surface-energy budget effects may be more important than the carbon-cycle effects. However, land-use impacts on climate cannot be adequately quantified with the usual metric of 'global warming potential'. A new metric is needed to quantify the human disturbance of the Earth's surface-energy budget. This 'regional climate change potential' could offer a new metric for developing a more inclusive climate protocol. This concept would also implicitly provide a mechanism to monitor potential local-scale environmental changes that could influence biodiversity.

The value and limitations of global air-sampling networks for improving our understanding trace gas behavior

NASA Astrophysics Data System (ADS)

Montzka, S. A.

2016-12-01

Measurements from global surface-based air sampling networks provide a fundamental understanding of how and why concentrations of long-lived trace gases are changing over time. Results from these networks are used to quantify trace-gas concentrations and their time-dependent changes on global and smaller scales, and thus provide a means to quantify emission rates, loss frequencies, and mixing processes. Substantial advances in measurement and sampling technologies and the ability of these programs to create and maintain reliable gas standards mean that spatial concentration gradients and time-dependent changes are often very reliably measured. The presence of multiple independent networks allows an assessment of this reliability. Furthermore, recent global `snap-shot' surveys (e.g., HIPPO and ATom) and ongoing atmospheric profiling programs help us assess the ability of surface-based data to describe concentration distributions throughout most of the atmosphere ( 80% of its mass). In this overview talk, I'll explore the usefulness and limitations of existing long-term, ongoing sampling network programs and their advantages and disadvantages for characterizing concentrations on global and regional scales, and how recent advances (and short-term sampling programs) help us assess the accuracy of the surface networks to provide estimates of source and sink magnitudes, and inter-annual variability in both.

Mangrove species' responses to winter air temperature extremes in China

USGS Publications Warehouse

Chen, Luzhen; Wang, Wenqing; Li, Qingshun Q.; Zhang, Yihui; Yang, Shengchang; Osland, Michael J.; Huang, Jinliang; Peng, Congjiao

2017-01-01

The global distribution and diversity of mangrove forests is greatly influenced by the frequency and intensity of winter air temperature extremes. However, our understanding of how different mangrove species respond to winter temperature extremes has been lacking because extreme freezing and chilling events are, by definition, relatively uncommon and also difficult to replicate experimentally. In this study, we investigated species-specific variation in mangrove responses to winter temperature extremes in China. In 10 sites that span a latitudinal gradient, we quantified species-specific damage and recovery following a chilling event, for mangrove species within and outside of their natural range (i.e., native and non-native species, respectively). To characterize plant stress, we measured tree defoliation and chlorophyll fluorescence approximately one month following the chilling event. To quantify recovery, we measured chlorophyll fluorescence approximately nine months after the chilling event. Our results show high variation in the geographic- and species-specific responses of mangroves to winter temperature extremes. While many species were sensitive to the chilling temperatures (e.g., Bruguiera sexangula and species in the Sonneratia and Rhizophora genera), the temperatures during this event were not cold enough to affect certain species (e.g., Kandelia obovata, Aegiceras corniculatum, Avicennia marina, and Bruguiera gymnorrhiza). As expected, non-native species were less tolerant of winter temperature extremes than native species. Interestingly, tidal inundation modulated the effects of chilling. In comparison with other temperature-controlled mangrove range limits across the world, the mangrove range limit in China is unique due to the combination of the following three factors: (1) Mangrove species diversity is comparatively high; (2) winter air temperature extremes, rather than means, are particularly intense and play an important ecological role; and (3) due to afforestation and restoration efforts, several species of non-native mangroves have been introduced beyond their natural range limits. Hence, from a global perspective, mangroves in China provide valuable opportunities to advance understanding of the effects of freezing and chilling temperatures on mangroves. Within the context of climate change, our findings provide a foundation for better understanding and preparing for mangrove species-specific responses to future changes in the duration and intensity of winter temperature extremes.

Preservative-free versus preserved latanoprost eye drops in patients with open-angle glaucoma or ocular hypertension.

PubMed

Aptel, Florent; Choudhry, Reena; Stalmans, Ingeborg

2016-08-01

This study compared the efficacy, safety, and pharmacokinetics of a preservative-free latanoprost formulation to an established, benzalkonium chloride (BAK) containing formulation for the treatment of open-angle glaucoma or ocular hypertension. This was a phase II, randomized, cross-over, investigator-masked, multi-center, pilot study (NCT01494753). A total of 30 untreated adult patients (aged ≥18 years) with primary open angle glaucoma, pseudo-exfoliative glaucoma, pigmentary glaucoma, or ocular hypertension received either preservative-free or preserved latanoprost once daily in both eyes for 6 weeks, before crossing over to receive the other treatment. Efficacy (intraocular pressure [IOP] at 8 am, midday, 4 pm and 8 pm, and global efficacy assessment by investigator), safety (adverse events, ocular symptoms and global tolerance, slit lamp examination, funduscopy, visual field examination, visual acuity, and heart rate), and pharmacokinetics were assessed at Days 0, 42, and 84. Both treatments resulted in a reduction in IOP that was similar for the preservative-free and the preserved formulation at all time points. Similarly, the overall diurnal reduction was similar in both groups (6.3 mmHg [27.9% reduction] and 6.4 mmHg [28.1% reduction] for preserved and preservative-free latanoprost, respectively). There were no differences in global efficacy assessment or in the safety and tolerance of each treatment. Systemic concentrations of latanoprost were very low; AUC0-30 and Cmax were lower and tmax was longer for preservative-free latanoprost. Preservative-free latanoprost showed similar efficacy at all time points compared to BAK preservative containing formulation, with no difference in tolerance, allowing progression to phase III clinical development.

Avocado and soybean extracts as active principles in the treatment of mild-to-moderate vulvar lichen sclerosus: results of efficacy and tolerability.

PubMed

Borghi, A; Corazza, M; Minghetti, S; Toni, G; Virgili, A

2015-06-01

Limited evidence is available on the effectiveness of treatments alternative to corticosteroids for vulvar lichen sclerosus (VLS). The present study aimed to assess the efficacy and tolerability of avocado and soybean extracts (ASE) as active principles of both a topical product and a nutritional supplement in the treatment of active mild-to-moderate VLS. Twenty-three patients were enrolled. Treatment consisted of a topical product containing ASE and other lenitive and anti-oxidant principles administered twice daily for 24 weeks, in association with a dietary supplement containing ASE, vitamin E and para-aminobenzoic acid for the first 12 weeks. The primary efficacy endpoint was the rate of patients achieving an improvement from baseline in global subjective score (GSS) and global objective score (GOS) of ≥ 75%. Secondary efficacy endpoint was the rate of patients achieving GSS50 and GOS50. Tertiary efficacy endpoint was the mean reduction in subjective and objective scores throughout the treatment. By the end of the 24-week treatment, 12 (70.5% of symptomatic patients) and 13 patients (72.2%) achieved an improvement of at least 75% in subjective and objective global scores, respectively; 100% and 88.9% reached GSS50 and GOS50, respectively. Mean symptom and sign scores decreased significantly after treatment. The treatment was well tolerated. Our results provide evidence that the topical and dietary supplements used in the study, which contain active principles exerting anti-inflammatory, anti-fibrotic, emollient and lenitive actions, are effective alternatives in the treatment of symptoms and signs of mild-to-moderate VLS. © 2014 European Academy of Dermatology and Venereology.

Fighting the Global War on Terror Tolerably: Augmenting the Global Counter Insurgency Strategy with Surrogates

DTIC Science & Technology

2007-03-27

186, 198 36 their cattle .114 It was left to the BATT to determine how to overcome these predicaments; from forgoing the element of surprise and...demonstrating the CAS to planning and executing what might be the first cattle drive to be conducted with CAS and artillery providing security. For all...demonstrated that the Firqat were not pawns of the British. The relegation of the Harkis to a constant subordinate role effectively castrated them in the

Integrating both interaction pathways between warming and pesticide exposure on upper thermal tolerance in high- and low-latitude populations of an aquatic insect.

PubMed

Op de Beeck, Lin; Verheyen, Julie; Stoks, Robby

2017-05-01

Global warming and chemical pollution are key anthropogenic stressors with the potential to interact. While warming can change the impact of pollutants and pollutants can change the sensitivity to warming, both interaction pathways have never been integrated in a single experiment. Therefore, we tested the effects of warming and multiple pesticide pulses (allowing accumulation) of chlorpyrifos on upper thermal tolerance (CTmax) and associated physiological traits related to aerobic/anaerobic energy production in the damselfly Ischnura elegans. To also assess the role of latitude-specific thermal adaptation in shaping the impact of warming and pesticide exposure on thermal tolerance, we exposed larvae from replicated high- and low-latitude populations to the pesticide in a common garden rearing experiment at 20 and 24 °C, the mean summer water temperatures at high and low latitudes. As expected, exposure to chlorpyrifos resulted in a lower CTmax. Yet, this pesticide effect on CTmax was lower at 24 °C compared to 20 °C because of a lower accumulation of chlorpyrifos in the medium at 24 °C. The effects on CTmax could partly be explained by reduction of the aerobic scope. Given that these effects did not differ between latitudes, gradual thermal evolution is not expected to counteract the negative effect of the pesticide on thermal tolerance. By for the first time integrating both interaction pathways we were not only able to provide support for both of them, but more importantly demonstrate that they can directly affect each other. Indeed, the warming-induced reduction in pesticide impact generated a lower pesticide-induced climate change sensitivity (in terms of decreased upper thermal tolerance). Our results indicate that, assuming no increase in pesticide input, global warming might reduce the negative effect of multiple pulse exposures to pesticides on sensitivity to elevated temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improving Ethanol Tolerance of Escherichia coli by Rewiring Its Global Regulator cAMP Receptor Protein (CRP)

PubMed Central

Yeow, Jianwei; Wang, Ivy; Zhang, Hongfang; Song, Hao; Jiang, Rongrong

2013-01-01

A major challenge in bioethanol fermentation is the low tolerance of the microbial host towards the end product bioethanol. Here we report to improve the ethanol tolerance of E. coli from the transcriptional level by engineering its global transcription factor cAMP receptor protein (CRP), which is known to regulate over 400 genes in E. coli. Three ethanol tolerant CRP mutants (E1– E3) were identified from error-prone PCR libraries. The best ethanol-tolerant strain E2 (M59T) had the growth rate of 0.08 h−1 in 62 g/L ethanol, higher than that of the control at 0.06 h−1. The M59T mutation was then integrated into the genome to create variant iE2. When exposed to 150 g/l ethanol, the survival of iE2 after 15 min was about 12%, while that of BW25113 was <0.01%. Quantitative real-time reverse transcription PCR analysis (RT-PCR) on 444 CRP-regulated genes using OpenArray® technology revealed that 203 genes were differentially expressed in iE2 in the absence of ethanol, whereas 92 displayed differential expression when facing ethanol stress. These genes belong to various functional groups, including central intermediary metabolism (aceE, acnA, sdhD, sucA), iron ion transport (entH, entD, fecA, fecB), and general stress response (osmY, rpoS). Six up-regulated and twelve down-regulated common genes were found in both iE2 and E2 under ethanol stress, whereas over one hundred common genes showed differential expression in the absence of ethanol. Based on the RT-PCR results, entA, marA or bhsA was knocked out in iE2 and the resulting strains became more sensitive towards ethanol. PMID:23469036

Summer dormancy, drought survival and functional resource acquisition strategies in California perennial grasses

PubMed Central

Balachowski, Jennifer A.; Bristiel, Pauline M.; Volaire, Florence A.

2016-01-01

Background and Aims Evidence suggests drought severity is increasing due to climate change, but strategies promoting severe drought survival in perennial grasses have been seldom explored. This is particularly true of summer dormancy, an adaptation common in summer-dry Mediterranean-type climates. In addition, though theory predicts superior drought survival results in lower potential productivity, studies rarely measure both drought survival and growth under optimal conditions. Methods Physiological and functional ecological approaches were integrated to quantify interspecific variation in foliar and root traits in a suite of eight California perennial grass species. In a glasshouse experiment, summer dormancy, foliar functional trait variation, and seasonal growth and phenology under non-limiting water conditions and dehydration tolerance under progressive drought were quantified. In a second glasshouse study, root functional traits were quantified under non-limiting water conditions in rhizotrons. Key Results Summer dormancy was associated with higher dehydration tolerance, and negatively associated with traits conferring dehydration avoidance. Species with greater summer dormancy were characterized by greater springtime productivity, earlier reproduction, and a shallow and fine root system, which are indicative of dehydration escape. Summer dormancy was associated with an acquisitive, competitive functional strategy in spring, and a conservative strategy in summer. Conclusions Both the escape and acquisitive springtime strategies observed in summer dormant perennial taxa are typically associated with annual grasses. California grasslands were once dominated by perennial species, but have been overtaken by non-native Mediterranean annual grasses, which are expected to be further favoured by climate change. Owing to functional similarity with these exotic annuals, it is suggested that native summer dormant taxa may play an important ecological role in the future of both natural and restored California grasslands. PMID:27325898

Baseline severity but not gender modulates quantified Crataegus extract effects in early heart failure--a pooled analysis of clinical trials.

PubMed

Eggeling, Thomas; Regitz-Zagrosek, Vera; Zimmermann, Andrea; Burkart, Martin

2011-11-15

The efficacy of quantified Crataegus extract in chronic heart failure (CHF) has been assessed in numerous clinical studies. The present pooled analysis evaluates the impact of baseline severity and gender on objective and patient-reported endpoints and associations between both types of outcomes in patients with early CHF. Available data from 687 individual patients treated with quantified Crataegus extract or placebo in ten studies were pooled. Treatment effects on physiologic outcome parameters and on symptoms were analysed for their association with baseline severity and gender. Changes in symptom scores were investigated with respect to their relation to physiologic outcome parameters. Results were compared with observations in a 3-year cohort study. Physiologic outcome parameters maximal workload (MWL), left ventricular ejection fraction (LVEF) and pressure-heart rate product increase (PHRPI) at 50 W ergometric exercise improved more in active treatment than in placebo patients. Magnitude of improvement was independent from baseline for LVEF but increased for MWL and PHRPI with baseline severity. Improvement of typical symptoms like reduced exercise tolerance, exertional dyspnea, weakness, fatigue, and palpitations improved more with active treatment and in patients with more severe symptoms. A weak association between improvements in MWL, PRHP, and symptoms could be demonstrated. Gender differences in treatment effects could be explained by baseline differences. Results of the pooled analysis are in agreement with observations in the cohort study. Crataegus extract treatment effects on physiologic outcomes and typical symptoms were modulated by baseline severity. Taking baseline differences into account, benefits were comparable in male and female patients with impaired exercise-tolerance in early chronic heart-failure. Copyright © 2011 Elsevier GmbH. All rights reserved.

Distinguishing the central drive to tremor in Parkinson's disease and essential tremor.

PubMed

Brittain, John-Stuart; Cagnan, Hayriye; Mehta, Arpan R; Saifee, Tabish A; Edwards, Mark J; Brown, Peter

2015-01-14

Parkinson's disease (PD) and essential tremor (ET) are the two most common movement disorders. Both have been associated with similar patterns of network activation leading to the suggestion that they may result from similar network dysfunction, specifically involving the cerebellum. Here, we demonstrate that parkinsonian tremors and ETs result from distinct patterns of interactions between neural oscillators. These patterns are reflected in the tremors' derived frequency tolerance, a novel measure readily attainable from bedside accelerometry. Frequency tolerance characterizes the temporal evolution of tremor by quantifying the range of frequencies over which the tremor may be considered stable. We found that patients with PD (N = 24) and ET (N = 21) were separable based on their frequency tolerance, with PD associated with a broad range of stable frequencies whereas ET displayed characteristics consistent with a more finely tuned oscillatory drive. Furthermore, tremor was selectively entrained by transcranial alternating current stimulation applied over cerebellum. Narrow frequency tolerances predicted stronger entrainment of tremor by stimulation, providing good evidence that the cerebellum plays an important role in pacing those tremors. The different patterns of frequency tolerance could be captured with a simple model based on a broadly coupled set of neural oscillators for PD, but a more finely tuned set of oscillators in ET. Together, these results reveal a potential organizational principle of the human motor system, whose disruption in PD and ET dictates how patients respond to empirical, and potentially therapeutic, interventions that interact with their underlying pathophysiology. Copyright © 2015 Brittain et al.

Heavy metal tolerance and removal potential in mixed-species biofilm.

PubMed

Grujić, Sandra; Vasić, Sava; Čomić, Ljiljana; Ostojić, Aleksandar; Radojević, Ivana

2017-08-01

The aim of the study was to examine heavy metal tolerance (Cd 2+ , Zn 2+ , Ni 2+ and Cu 2+ ) of single- and mixed-species biofilms (Rhodotorula mucilaginosa and Escherichia coli) and to determine metal removal efficiency (Cd 2+ , Zn 2+ , Ni 2+ , Cu 2+ , Pb 2+ and Hg 2+ ). Metal tolerance was quantified by crystal violet assay and results were confirmed by fluorescence microscopy. Metal removal efficiency was determined by batch biosorption assay. The tolerance of the mixed-species biofilm was higher than the single-species biofilms. Single- and mixed-species biofilms showed the highest sensitivity in the presence of Cu 2+ (E. coli-MIC 4 mg/ml, R. mucilaginosa-MIC 8 mg/ml, R. mucilaginosa/E. coli-MIC 64 mg/ml), while the highest tolerance was observed in the presence of Zn 2+ (E. coli-MIC 80 mg/ml, R. mucilaginosa-MIC 161 mg/ml, R. mucilaginosa-E. coli-MIC 322 mg/ml). The mixed-species biofilm exhibited better efficiency in removal of all tested metals than single-species biofilms. The highest efficiency in Cd 2+ removal was shown by the E. coli biofilm (94.85%) and R. mucilaginosa biofilm (97.85%), individually. The highest efficiency in Cu 2+ (99.88%), Zn 2+ (99.26%) and Pb 2+ (99.52%) removal was shown by the mixed-species biofilm. Metal removal efficiency was in the range of 81.56%-97.85% for the single- and 94.99%-99.88% for the mixed-species biofilm.

Distinguishing the Central Drive to Tremor in Parkinson's Disease and Essential Tremor

PubMed Central

Brittain, John-Stuart; Cagnan, Hayriye; Mehta, Arpan R.; Saifee, Tabish A.; Edwards, Mark J.

2015-01-01

Parkinson's disease (PD) and essential tremor (ET) are the two most common movement disorders. Both have been associated with similar patterns of network activation leading to the suggestion that they may result from similar network dysfunction, specifically involving the cerebellum. Here, we demonstrate that parkinsonian tremors and ETs result from distinct patterns of interactions between neural oscillators. These patterns are reflected in the tremors' derived frequency tolerance, a novel measure readily attainable from bedside accelerometry. Frequency tolerance characterizes the temporal evolution of tremor by quantifying the range of frequencies over which the tremor may be considered stable. We found that patients with PD (N = 24) and ET (N = 21) were separable based on their frequency tolerance, with PD associated with a broad range of stable frequencies whereas ET displayed characteristics consistent with a more finely tuned oscillatory drive. Furthermore, tremor was selectively entrained by transcranial alternating current stimulation applied over cerebellum. Narrow frequency tolerances predicted stronger entrainment of tremor by stimulation, providing good evidence that the cerebellum plays an important role in pacing those tremors. The different patterns of frequency tolerance could be captured with a simple model based on a broadly coupled set of neural oscillators for PD, but a more finely tuned set of oscillators in ET. Together, these results reveal a potential organizational principle of the human motor system, whose disruption in PD and ET dictates how patients respond to empirical, and potentially therapeutic, interventions that interact with their underlying pathophysiology. PMID:25589772

Expression of Finger Millet EcDehydrin7 in Transgenic Tobacco Confers Tolerance to Drought Stress.

PubMed

Singh, Rajiv Kumar; Singh, Vivek Kumar; Raghavendrarao, Sanagala; Phanindra, Mullapudi Lakshmi Venkata; Venkat Raman, K; Solanke, Amolkumar U; Kumar, Polumetla Ananda; Sharma, Tilak Raj

2015-09-01

One of the critical alarming constraints for agriculture is water scarcity. In the current scenario, global warming due to climate change and unpredictable rainfall, drought is going to be a master player and possess a big threat to stagnating gene pool of staple food crops. So it is necessary to understand the mechanisms that enable the plants to cope with drought stress. In this study, effort was made to prospect the role of EcDehydrin7 protein from normalized cDNA library of drought tolerance finger millet in transgenic tobacco. Biochemical and molecular analyses of T0 transgenic plants were done for stress tolerance. Leaf disc assay, seed germination test, dehydration assay, and chlorophyll estimation showed EcDehydrin7 protein directly link to drought tolerance. Northern and qRT PCR analyses shows relatively high expression of EcDehydrin7 protein compare to wild type. T0 transgenic lines EcDehydrin7(11) and EcDehydrin7(15) shows superior expression among all lines under study. In summary, all results suggest that EcDehydrin7 protein has a remarkable role in drought tolerance and may be used for sustainable crop breeding program in other food crops.

Quantitative trait loci mapping of heat tolerance in broccoli (Brassica oleracea var. italica) using genotyping-by-sequencing.

PubMed

Branham, Sandra E; Stansell, Zachary J; Couillard, David M; Farnham, Mark W

2017-03-01

Five quantitative trait loci and one epistatic interaction were associated with heat tolerance in a doubled haploid population of broccoli evaluated in three summer field trials. Predicted rising global temperatures due to climate change have generated a demand for crops that are resistant to yield and quality losses from heat stress. Broccoli (Brassica oleracea var. italica) is a cool weather crop with high temperatures during production decreasing both head quality and yield. Breeding for heat tolerance in broccoli has potential to both expand viable production areas and extend the growing season but breeding efficiency is constrained by limited genetic information. A doubled haploid (DH) broccoli population segregating for heat tolerance was evaluated for head quality in three summer fields in Charleston, SC, USA. Multiple quantitative trait loci (QTL) mapping of 1,423 single nucleotide polymorphisms developed through genotyping-by-sequencing identified five QTL and one positive epistatic interaction that explained 62.1% of variation in heat tolerance. The QTL identified here can be used to develop markers for marker-assisted selection and to increase our understanding of the molecular mechanisms underlying plant response to heat stress.

Creation of forest edges has a global impact on forest vertebrates.

PubMed

Pfeifer, M; Lefebvre, V; Peres, C A; Banks-Leite, C; Wearn, O R; Marsh, C J; Butchart, S H M; Arroyo-Rodríguez, V; Barlow, J; Cerezo, A; Cisneros, L; D'Cruze, N; Faria, D; Hadley, A; Harris, S M; Klingbeil, B T; Kormann, U; Lens, L; Medina-Rangel, G F; Morante-Filho, J C; Olivier, P; Peters, S L; Pidgeon, A; Ribeiro, D B; Scherber, C; Schneider-Maunoury, L; Struebig, M; Urbina-Cardona, N; Watling, J I; Willig, M R; Wood, E M; Ewers, R M

2017-11-09

Forest edges influence more than half of the world's forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1,673 vertebrate species. We show that the abundances of 85% of species are affected, either positively or negatively, by forest edges. Species that live in the centre of the forest (forest core), that were more likely to be listed as threatened by the International Union for Conservation of Nature (IUCN), reached peak abundances only at sites farther than 200-400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest-core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale.

Creation of forest edges has a global impact on forest vertebrates

NASA Astrophysics Data System (ADS)

Pfeifer, M.; Lefebvre, V.; Peres, C. A.; Banks-Leite, C.; Wearn, O. R.; Marsh, C. J.; Butchart, S. H. M.; Arroyo-Rodríguez, V.; Barlow, J.; Cerezo, A.; Cisneros, L.; D'Cruze, N.; Faria, D.; Hadley, A.; Harris, S. M.; Klingbeil, B. T.; Kormann, U.; Lens, L.; Medina-Rangel, G. F.; Morante-Filho, J. C.; Olivier, P.; Peters, S. L.; Pidgeon, A.; Ribeiro, D. B.; Scherber, C.; Schneider-Maunoury, L.; Struebig, M.; Urbina-Cardona, N.; Watling, J. I.; Willig, M. R.; Wood, E. M.; Ewers, R. M.

2017-11-01

Forest edges influence more than half of the world’s forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1,673 vertebrate species. We show that the abundances of 85% of species are affected, either positively or negatively, by forest edges. Species that live in the centre of the forest (forest core), that were more likely to be listed as threatened by the International Union for Conservation of Nature (IUCN), reached peak abundances only at sites farther than 200-400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest-core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale.

Phytochelatins play a key role in arsenic accumulation and tolerance in the aquatic macrophyte Wolffia globosa.

PubMed

Zhang, Xin; Uroic, M Kalle; Xie, Wan-Ying; Zhu, Yong-Guan; Chen, Bao-Dong; McGrath, Steve P; Feldmann, Jörg; Zhao, Fang-Jie

2012-06-01

The rootless duckweed Wolffia globosa can accumulate and tolerate relatively large amounts of arsenic (As); however, the underlying mechanisms were unknown. W. globosa was exposed to different concentrations of arsenate with or without l-buthionine sulphoximine (BSO), a specific inhibitor of γ-glutamylcysteine synthetase. Free thiol compounds and As(III)-thiol complexes were identified and quantified using HPLC - high resolution ICP-MS - accurate mass ESI-MS. Without BSO, 74% of the As accumulated in the duckweed was complexed with phytochelatins (PCs), with As(III)-PC(4) and As(III)-PC(3) being the main species. BSO was taken up by the duckweed and partly deaminated. The BSO treatment completely suppressed the synthesis of PCs and the formation of As(III)-PC complexes, and also inhibited the reduction of arsenate to arsenite. BSO markedly decreased both As accumulation and As tolerance in W. globosa. The results demonstrate an important role of PCs in detoxifying As and enabling As accumulation in W. globosa. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mechanisms Underlying CD4+ Treg Immune Regulation in the Adult: From Experiments to Models

DOE PAGES

Caridade, Marta; Graca, Luis; Ribeiro, Ruy M.

2013-11-18

To maintain immunological balance the organism has to be tolerant to self while remaining competent to mount an effective immune response against third-party antigens. An important mechanism of this immune regulation involves the action of regulatory T-cell (Tregs). In this mini-review, we discuss some of the known and proposed mechanisms by which Tregs exert their influence in the context of immune regulation, and the contribution of mathematical modeling for these mechanistic studies. These models explore the mechanisms of action of regulatory T cells, and include hypotheses of multiple signals, delivered through simultaneous antigen-presenting cell (APC) conjugation; interaction of feedback loopsmore » between APC, Tregs, and effector cells; or production of specific cytokines that act on effector cells. As the field matures, and competing models are winnowed out, it is likely that we will be able to quantify how tolerance-inducing strategies, such as CD4-blockade, affect T-cell dynamics and what mechanisms explain the observed behavior of T-cell based tolerance.« less

Assessment of the short-term safety and tolerability of a quantified 80 % ethanol extract from the stem bark of Nauclea pobeguinii (PR 259 CT1) in healthy volunteers: a clinical phase I study.

PubMed

Mesia, Kahunu; Cimanga, Kanyanga; Tona, Lutete; Mampunza, Ma Miezi; Ntamabyaliro, Nsengi; Muanda, Tsobo; Muyembe, Tamfum; Totté, Jozef; Mets, Tony; Pieters, Luc; Vlietinck, Arnold

2011-01-01

The aim of this study was to evaluate the short-term safety and tolerability of an antimalarial herbal medicinal product (PR 259 CT1) consisting of a quantified 80 % ethanol extract from the stem bark of Nauclea pobeguinii when given orally to healthy adult male volunteers. The amount of the major alkaloid strictosamide in the extract was determined by a validated HPLC method and was shown to be 5.6 %. The herbal preparation was formulated in a gelatine capsule form containing 500 mg of PCR 259 CT1. A sample of 15 healthy male volunteers, selected using the Lot Quality Assurance of Sampling (LQAS) method, was eligible for inclusion after fulfillment of the inclusion criteria and clinical examination by a physician. The volunteers were treated in an outpatient clinic with a drug regimen of two 500 mg capsules three times daily (each eight hours) for seven days, during meals. Safety and tolerability were monitored clinically, haematologically, biochemically and by electrocardiographic (ECG) examination at days 0, 1, 3, 7 and 14. Adverse effects were recorded by self-reporting of the participants or by detection of abnormalities in clinical examinations by a physician. The oral administration of PR 259 CT1 at high doses of 2 × 500 mg/capsule/day for 7 days was found to induce no significant changes in the concentration levels of all investigated haematological, biochemical, electrocardiogram and vital sign parameters and physical characteristics after 14 days of treatment compared to those seen in the baseline data. The concentration levels of all evaluated parameters were within the normal limits as reported in the literature. All adverse events noted were mild and self-resolving including increase of appetite (33 %), headache (20 %) and nausea (20 %). Other minor side effects were insomnia, somnolence and asthenia (7 %). Thus, PR 259 CT1 presented a significant safety and tolerability in healthy volunteers to allow its further development by starting a phase II clinical trial. © Georg Thieme Verlag KG Stuttgart · New York.

A randomized, double-blind study of the efficacy and tolerability of extended-release quetiapine fumarate (quetiapine XR) monotherapy in patients with major depressive disorder

PubMed Central

Wang, Gang; McIntyre, Alexander; Earley, Willie R; Raines, Shane R; Eriksson, Hans

2014-01-01

Objectives To evaluate the efficacy and tolerability of once-daily extended release quetiapine fumarate (quetiapine XR) monotherapy in patients with major depressive disorder (MDD). Patients and methods This was a 10-week (8-week active treatment/2-week post-treatment) randomized, double-blind, placebo- and active-controlled study (D1448C00004). Patients received quetiapine XR 150 mg/day, escitalopram 10 mg/day, or placebo; patients with an inadequate response (<20% improvement in Montgomery–Åsberg Depression Rating Scale [MADRS] total score) at week two received double-dose treatment. The primary end point was week eight change from randomization in MADRS total score. Secondary end points included MADRS response (≥50% improvement) and remission (score ≤8); Hamilton Rating Scale for Depression total and item 1; Hamilton Rating Scale for Anxiety total, psychic, and somatic; Clinical Global Impressions – Severity of Illness total; Pittsburgh Sleep Quality Index (PSQI) global; and Quality of Life Enjoyment and Satisfaction Questionnaire – Short Form percentage maximum total scores. Tolerability was assessed throughout. Results A total of 471 patients was randomized. No significant improvements in MADRS total score were observed at week eight (last observation carried forward) with either active treatment (quetiapine XR, −17.21 [P=0.174]; escitalopram, −16.73 [P=0.346]) versus placebo (−15.61). There were no significant differences in secondary end points versus placebo, with the exception of week-eight change in PSQI global score (quetiapine XR, −4.96 [P<0.01] versus placebo, −3.37). Mixed-model repeated-measures analysis of observed-case data suggested that the primary analysis may not be robust. Most commonly reported adverse events included dry mouth, somnolence, and dizziness for quetiapine XR, and headache and nausea for escitalopram. Conclusion In this study, neither quetiapine XR (150/300 mg/day) nor escitalopram (10/20 mg/day) showed significant separation from placebo. Both compounds have been shown previously to be effective in the treatment of MDD; possible reasons for this failed study are discussed. Quetiapine XR was generally well tolerated, with a profile similar to that reported previously. PMID:24511235

Characterization of genetic diversity of high temperature tolerance in sorghum

USDA-ARS?s Scientific Manuscript database

As global warming becomes inevitable, the sustainability of agricultural production in US and worldwide faces serious threat from extreme weather conditions, such as drought and elevated extreme temperatures (heat waves). Among cereal crops, sorghum is considered a versatile crop for semiarid area a...

Interactions of climate, socio-economics, and global mercury pollution in the North Water.

PubMed

Dietz, Rune; Mosbech, Anders; Flora, Janne; Eulaers, Igor

2018-04-01

Despite the remoteness of the North Water, Northwest Greenland, the local Inughuit population is affected by global anthropogenic pollution and climate change. Using a cross-disciplinary approach combining Mercury (Hg) analysis, catch information, and historical and anthropological perspectives, this article elucidates how the traditional diet is compromised by Hg pollution originating from lower latitudes. In a new approach we here show how the Inughuits in Avanersuaq are subject to high Hg exposure from the hunted traditional food, consisting of mainly marine seabirds and mammals. Violation of the provisional tolerably yearly intake of Hg, on average by a factor of 11 (range 7-15) over the last 20 years as well as the provisional tolerably monthly intake by a factor of 6 (range 2-16), raises health concerns. The surplus of Selenium (Se) in wildlife tissues including narwhals showed Se:Hg molar ratios of 1.5, 2.3, and 16.7 in muscle, liver, and mattak, respectively, likely to provide some protection against the high Hg exposure.

The core legion object model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, M.; Grimshaw, A.

1996-12-31

The Legion project at the University of Virginia is an architecture for designing and building system services that provide the illusion of a single virtual machine to users, a virtual machine that provides secure shared object and shared name spaces, application adjustable fault-tolerance, improved response time, and greater throughput. Legion targets wide area assemblies of workstations, supercomputers, and parallel supercomputers, Legion tackles problems not solved by existing workstation based parallel processing tools; the system will enable fault-tolerance, wide area parallel processing, inter-operability, heterogeneity, a single global name space, protection, security, efficient scheduling, and comprehensive resource management. This paper describes themore » core Legion object model, which specifies the composition and functionality of Legion`s core objects-those objects that cooperate to create, locate, manage, and remove objects in the Legion system. The object model facilitates a flexible extensible implementation, provides a single global name space, grants site autonomy to participating organizations, and scales to millions of sites and trillions of objects.« less

Dehydration induced transcriptomic responses in two Tibetan hulless barley (Hordeum vulgare var. nudum) accessions distinguished by drought tolerance.

PubMed

Liang, Junjun; Chen, Xin; Deng, Guangbing; Pan, Zhifen; Zhang, Haili; Li, Qiao; Yang, Kaijun; Long, Hai; Yu, Maoqun

2017-10-11

The harsh environment on the Qinghai-Tibetan Plateau gives Tibetan hulless barley (Hordeum vulgare var. nudum) great ability to resist adversities such as drought, salinity, and low temperature, and makes it a good subject for the analysis of drought tolerance mechanism. To elucidate the specific gene networks and pathways that contribute to its drought tolerance, and for identifying new candidate genes for breeding purposes, we performed a transcriptomic analysis using two accessions of Tibetan hulless barley, namely Z772 (drought-tolerant) and Z013 (drought-sensitive). There were more up-regulated genes of Z772 than Z013 under both mild (5439-VS-2604) and severe (7203-VS-3359) dehydration treatments. Under mild dehydration stress, the pathways exclusively enriched in drought-tolerance genotype Z772 included Protein processing in endoplasmic reticulum, tricarboxylic acid (TCA) cycle, Wax biosynthesis, and Spliceosome. Under severe dehydration stress, the pathways that were mainly enriched in Z772 included Carbon fixation in photosynthetic organisms, Pyruvate metabolism, Porphyrin and chlorophyll metabolism. The main differentially expressed genes (DEGs) in response to dehydration stress and genes whose expression was different between tolerant and sensitive genotypes were presented in this study, respectively. The candidate genes for drought tolerance were selected based on their expression patterns. The RNA-Seq data obtained in this study provided an initial overview on global gene expression patterns and networks that related to dehydration shock in Tibetan hulless barley. Furthermore, these data provided pathways and a targeted set of candidate genes that might be essential for deep analyzing the molecular mechanisms of plant tolerance to drought stress.

Grazing Incidence Optics for X-rays Interferometry

NASA Technical Reports Server (NTRS)

Shipley, Ann; Zissa, David; Cash, Webster; Joy, Marshall

1999-01-01

Grazing incidence mirror parameters and constraints for x-ray interferometry are described. We present interferometer system tolerances and ray trace results used to define mirror surface accuracy requirements. Mirror material, surface figure, roughness, and geometry are evaluated based on analysis results. We also discuss mirror mount design constraints, finite element analysis, environmental issues, and solutions. Challenges associated with quantifying high accuracy mirror surface quality are addressed and test results are compared with theoretical predictions.

Revealing the underlying drivers of disaster risk: a global analysis

NASA Astrophysics Data System (ADS)

Peduzzi, Pascal

2017-04-01

Disasters events are perfect examples of compound events. Disaster risk lies at the intersection of several independent components such as hazard, exposure and vulnerability. Understanding the weight of each component requires extensive standardisation. Here, I show how footprints of past disastrous events were generated using GIS modelling techniques and used for extracting population and economic exposures based on distribution models. Using past event losses, it was possible to identify and quantify a wide range of socio-politico-economic drivers associated with human vulnerability. The analysis was applied to about nine thousand individual past disastrous events covering earthquakes, floods and tropical cyclones. Using a multiple regression analysis on these individual events it was possible to quantify each risk component and assess how vulnerability is influenced by various hazard intensities. The results show that hazard intensity, exposure, poverty, governance as well as other underlying factors (e.g. remoteness) can explain the magnitude of past disasters. Analysis was also performed to highlight the role of future trends in population and climate change and how this may impacts exposure to tropical cyclones in the future. GIS models combined with statistical multiple regression analysis provided a powerful methodology to identify, quantify and model disaster risk taking into account its various components. The same methodology can be applied to various types of risk at local to global scale. This method was applied and developed for the Global Risk Analysis of the Global Assessment Report on Disaster Risk Reduction (GAR). It was first applied on mortality risk in GAR 2009 and GAR 2011. New models ranging from global assets exposure and global flood hazard models were also recently developed to improve the resolution of the risk analysis and applied through CAPRA software to provide probabilistic economic risk assessments such as Average Annual Losses (AAL) and Probable Maximum Losses (PML) in GAR 2013 and GAR 2015. In parallel similar methodologies were developed to highlitght the role of ecosystems for Climate Change Adaptation (CCA) and Disaster Risk Reduction (DRR). New developments may include slow hazards (such as e.g. soil degradation and droughts), natech hazards (by intersecting with georeferenced critical infrastructures) The various global hazard, exposure and risk models can be visualized and download through the PREVIEW Global Risk Data Platform.

Monthly land cover-specific evapotranspiration models derived from global eddy flux measurements and remote sensing data

Treesearch

Yuan Fang; Ge Sun; Peter Caldwell; Steven G. McNulty; Asko Noormets; Jean-Christophe Domec; John King; Zhiqiang Zhang; Xudong Zhang; Guanghui Lin; Guangsheng Zhou; Jingfeng Xiao; Jiquan Chen

2015-01-01

Evapotranspiration (ET) is arguably the most uncertain ecohydrologic variable for quantifying watershed water budgets. Although numerous ET and hydrological models exist, accurately predicting the effects of global change on water use and availability remains challenging because of model deficiency and/or a lack of input parameters. The objective of this study was to...

Youth, Skills Development, and Work in the Education for All Global Monitoring Report 2012: Learning from Asia or for Asia?

ERIC Educational Resources Information Center

King, Kenneth

2014-01-01

The article underlines the historic importance of the treatment of skills development, finally, by the Education for All Global Monitoring Report (GMR) team. Among the many challenges in its analysis are the multiple and overlapping meanings of the word skill, and the consequent difficulties of quantifying and monitoring efforts at skills…

Global Digital Image Mosaics of Mars: Assessment of Geodetic Accuracy

NASA Technical Reports Server (NTRS)

Kirk, R.; Archinal, B. A.; Lee, E. M.; Davies, M. E.; Colvin, T. R.; Duxbury, T. C.

2001-01-01

A revised global image mosaic of Mars (MDIM 2.0) was recently completed by USGS. Comparison with high-resolution gridded Mars Orbiter Laser Altimeter (MOLA) digital image mosaics will allow us to quantify its geodetic errors; linking the next MDIM to the MOLA data will help eliminate those errors. Additional information is contained in the original extended abstract.

Global mapping of ecosystem services and conservation priorities

PubMed Central

Naidoo, R.; Balmford, A.; Costanza, R.; Fisher, B.; Green, R. E.; Lehner, B.; Malcolm, T. R.; Ricketts, T. H.

2008-01-01

Global efforts to conserve biodiversity have the potential to deliver economic benefits to people (i.e., “ecosystem services”). However, regions for which conservation benefits both biodiversity and ecosystem services cannot be identified unless ecosystem services can be quantified and valued and their areas of production mapped. Here we review the theory, data, and analyses needed to produce such maps and find that data availability allows us to quantify imperfect global proxies for only four ecosystem services. Using this incomplete set as an illustration, we compare ecosystem service maps with the global distributions of conventional targets for biodiversity conservation. Our preliminary results show that regions selected to maximize biodiversity provide no more ecosystem services than regions chosen randomly. Furthermore, spatial concordance among different services, and between ecosystem services and established conservation priorities, varies widely. Despite this lack of general concordance, “win–win” areas—regions important for both ecosystem services and biodiversity—can be usefully identified, both among ecoregions and at finer scales within them. An ambitious interdisciplinary research effort is needed to move beyond these preliminary and illustrative analyses to fully assess synergies and trade-offs in conserving biodiversity and ecosystem services. PMID:18621701

Global self-esteem and method effects: competing factor structures, longitudinal invariance, and response styles in adolescents.

PubMed

Urbán, Róbert; Szigeti, Réka; Kökönyei, Gyöngyi; Demetrovics, Zsolt

2014-06-01

The Rosenberg Self-Esteem Scale (RSES) is a widely used measure for assessing self-esteem, but its factor structure is debated. Our goals were to compare 10 alternative models for the RSES and to quantify and predict the method effects. This sample involves two waves (N =2,513 9th-grade and 2,370 10th-grade students) from five waves of a school-based longitudinal study. The RSES was administered in each wave. The global self-esteem factor with two latent method factors yielded the best fit to the data. The global factor explained a large amount of the common variance (61% and 46%); however, a relatively large proportion of the common variance was attributed to the negative method factor (34 % and 41%), and a small proportion of the common variance was explained by the positive method factor (5% and 13%). We conceptualized the method effect as a response style and found that being a girl and having a higher number of depressive symptoms were associated with both low self-esteem and negative response style, as measured by the negative method factor. Our study supported the one global self-esteem construct and quantified the method effects in adolescents.

Global self-esteem and method effects: competing factor structures, longitudinal invariance and response styles in adolescents

PubMed Central

Urbán, Róbert; Szigeti, Réka; Kökönyei, Gyöngyi; Demetrovics, Zsolt

2013-01-01

The Rosenberg Self-Esteem Scale (RSES) is a widely used measure for assessing self-esteem, but its factor structure is debated. Our goals were to compare 10 alternative models for RSES; and to quantify and predict the method effects. This sample involves two waves (N=2513 ninth-grade and 2370 tenth-grade students) from five waves of a school-based longitudinal study. RSES was administered in each wave. The global self-esteem factor with two latent method factors yielded the best fit to the data. The global factor explained large amount of the common variance (61% and 46%); however, a relatively large proportion of the common variance was attributed to the negative method factor (34 % and 41%), and a small proportion of the common variance was explained by the positive method factor (5% and 13%). We conceptualized the method effect as a response style, and found that being a girl and having higher number of depressive symptoms were associated with both low self-esteem and negative response style measured by the negative method factor. Our study supported the one global self-esteem construct and quantified the method effects in adolescents. PMID:24061931

Mapping permeability over the surface of the Earth

USGS Publications Warehouse

Gleeson, T.; Smith, L.; Moosdorf, N.; Hartmann, J.; Durr, H.H.; Manning, A.H.; Van Beek, L. P. H.; Jellinek, A. Mark

2011-01-01

Permeability, the ease of fluid flow through porous rocks and soils, is a fundamental but often poorly quantified component in the analysis of regional-scale water fluxes. Permeability is difficult to quantify because it varies over more than 13 orders of magnitude and is heterogeneous and dependent on flow direction. Indeed, at the regional scale, maps of permeability only exist for soil to depths of 1-2 m. Here we use an extensive compilation of results from hydrogeologic models to show that regional-scale (>5 km) permeability of consolidated and unconsolidated geologic units below soil horizons (hydrolithologies) can be characterized in a statistically meaningful way. The representative permeabilities of these hydrolithologies are used to map the distribution of near-surface (on the order of 100 m depth) permeability globally and over North America. The distribution of each hydrolithology is generally scale independent. The near-surface mean permeability is of the order of ???5 ?? 10-14 m2. The results provide the first global picture of near-surface permeability and will be of particular value for evaluating global water resources and modeling the influence of climate-surface-subsurface interactions on global climate change. Copyright ?? 2011 by the American Geophysical Union.

Mapping permeability over the surface of the Earth

USGS Publications Warehouse

Gleeson, Tom; Smith, Leslie; Moosdorf, Nils; Hartmann, Jens; Durr, Hans H.; Manning, Andrew H.; van Beek, Ludovicus P. H.; Jellinek, A. Mark

2011-01-01

Permeability, the ease of fluid flow through porous rocks and soils, is a fundamental but often poorly quantified component in the analysis of regional-scale water fluxes. Permeability is difficult to quantify because it varies over more than 13 orders of magnitude and is heterogeneous and dependent on flow direction. Indeed, at the regional scale, maps of permeability only exist for soil to depths of 1-2 m. Here we use an extensive compilation of results from hydrogeologic models to show that regional-scale (>5 km) permeability of consolidated and unconsolidated geologic units below soil horizons (hydrolithologies) can be characterized in a statistically meaningful way. The representative permeabilities of these hydrolithologies are used to map the distribution of near-surface (on the order of 100 m depth) permeability globally and over North America. The distribution of each hydrolithology is generally scale independent. The near-surface mean permeability is of the order of -5 x 10-14 m2. The results provide the first global picture of near-surface permeability and will be of particular value for evaluating global water resources and modeling the influence of climate-surface-subsurface interactions on global climate change.

Global risk of deadly heat

NASA Astrophysics Data System (ADS)

Mora, Camilo; Dousset, Bénédicte; Caldwell, Iain R.; Powell, Farrah E.; Geronimo, Rollan C.; Bielecki, Coral R.; Counsell, Chelsie W. W.; Dietrich, Bonnie S.; Johnston, Emily T.; Louis, Leo V.; Lucas, Matthew P.; McKenzie, Marie M.; Shea, Alessandra G.; Tseng, Han; Giambelluca, Thomas W.; Leon, Lisa R.; Hawkins, Ed; Trauernicht, Clay

2017-07-01

Climate change can increase the risk of conditions that exceed human thermoregulatory capacity. Although numerous studies report increased mortality associated with extreme heat events, quantifying the global risk of heat-related mortality remains challenging due to a lack of comparable data on heat-related deaths. Here we conducted a global analysis of documented lethal heat events to identify the climatic conditions associated with human death and then quantified the current and projected occurrence of such deadly climatic conditions worldwide. We reviewed papers published between 1980 and 2014, and found 783 cases of excess human mortality associated with heat from 164 cities in 36 countries. Based on the climatic conditions of those lethal heat events, we identified a global threshold beyond which daily mean surface air temperature and relative humidity become deadly. Around 30% of the world's population is currently exposed to climatic conditions exceeding this deadly threshold for at least 20 days a year. By 2100, this percentage is projected to increase to ~48% under a scenario with drastic reductions of greenhouse gas emissions and ~74% under a scenario of growing emissions. An increasing threat to human life from excess heat now seems almost inevitable, but will be greatly aggravated if greenhouse gases are not considerably reduced.

Aluminum Toxicity-Induced Alterations of Leaf Proteome in Two Citrus Species Differing in Aluminum Tolerance

PubMed Central

Li, Huan; Yang, Lin-Tong; Qi, Yi-Ping; Guo, Peng; Lu, Yi-Bin; Chen, Li-Song

2016-01-01

Seedlings of aluminum-tolerant ‘Xuegan’ (Citrus sinensis) and Al-intolerant ‘sour pummelo’ (Citrus grandis) were fertigated for 18 weeks with nutrient solution containing 0 and 1.2 mM AlCl3·6H2O. Al toxicity-induced inhibition of photosynthesis and the decrease of total soluble protein only occurred in C. grandis leaves, demonstrating that C. sinensis had higher Al tolerance than C. grandis. Using isobaric tags for relative and absolute quantification (iTRAQ), we obtained more Al toxicity-responsive proteins from C. sinensis than from C. grandis leaves, which might be responsible for the higher Al tolerance of C. sinensis. The following aspects might contribute to the Al tolerance of C. sinensis: (a) better maintenance of photosynthesis and energy balance via inducing photosynthesis and energy-related proteins; (b) less increased requirement for the detoxification of reactive oxygen species and other toxic compounds, such as aldehydes, and great improvement of the total ability of detoxification; and (c) upregulation of low-phosphorus-responsive proteins. Al toxicity-responsive proteins related to RNA regulation, protein metabolism, cellular transport and signal transduction might also play key roles in the higher Al tolerance of C. sinensis. We present the global picture of Al toxicity-induced alterations of protein profiles in citrus leaves, and identify some new Al toxicity-responsive proteins related to various biological processes. Our results provide some novel clues about plant Al tolerance. PMID:27455238

Phosphoproteomics and Bioinformatics Analyses of Spinal Cord Proteins in Rats with Morphine Tolerance

PubMed Central

Liaw, Wen-Jinn; Tsao, Cheng-Ming; Huang, Go-Shine; Wu, Chin-Chen; Ho, Shung-Tai; Wang, Jhi-Joung; Tao, Yuan-Xiang; Shui, Hao-Ai

2014-01-01

Introduction Morphine is the most effective pain-relieving drug, but it can cause unwanted side effects. Direct neuraxial administration of morphine to spinal cord not only can provide effective, reliable pain relief but also can prevent the development of supraspinal side effects. However, repeated neuraxial administration of morphine may still lead to morphine tolerance. Methods To better understand the mechanism that causes morphine tolerance, we induced tolerance in rats at the spinal cord level by giving them twice-daily injections of morphine (20 µg/10 µL) for 4 days. We confirmed tolerance by measuring paw withdrawal latencies and maximal possible analgesic effect of morphine on day 5. We then carried out phosphoproteomic analysis to investigate the global phosphorylation of spinal proteins associated with morphine tolerance. Finally, pull-down assays were used to identify phosphorylated types and sites of 14-3-3 proteins, and bioinformatics was applied to predict biological networks impacted by the morphine-regulated proteins. Results Our proteomics data showed that repeated morphine treatment altered phosphorylation of 10 proteins in the spinal cord. Pull-down assays identified 2 serine/threonine phosphorylated sites in 14-3-3 proteins. Bioinformatics further revealed that morphine impacted on cytoskeletal reorganization, neuroplasticity, protein folding and modulation, signal transduction and biomolecular metabolism. Conclusions Repeated morphine administration may affect multiple biological networks by altering protein phosphorylation. These data may provide insight into the mechanism that underlies the development of morphine tolerance. PMID:24392096

Indices of benthic community tolerance in contaminated Great Lakes sediments: Relations with sediment contaminant concentrations, sediment toxicity, and the sediment quality triad

USGS Publications Warehouse

Wildhaber, M.L.; Schmitt, C.J.

1998-01-01

We evaluated the toxic-units model developed by Wildhaber and Schmitt (1996) as a predictor of indices of mean tolerance to pollution (i.e., Lenat, 1993; Hilsenhoff, 1987) and other benthic community indices from Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls – PCBs, polycyclic aromatic hydrocarbons – PAHs, pesticides, chlorinated dioxins, and metals). Sediment toxic units were defined as the ratio of the estimated pore-water concentration of a contaminant to its chronic toxicity as estimated by U.S. Environmental Protection Agency Ambient Water Quality Criteria (AWQC) or other applicable standard. The total hazard of a sediment to aquatic life was assessed by summing toxic units for all contaminants quantified. Among the benthic community metrics evaluated, total toxic units were most closely correlated with Lenat's (1993) and Hilsenhoff's (1987) indices of community tolerance (TL and TH, respectively); toxic units accounted for 42% TL and 53% TH of variability in community tolerance as measured by Ponar grabs. In contrast, taxonomic richness and Shannon-Wiener diversity were not correlated (P > 0.05) with toxic units. Substitution of order- or family-level identifications for lowest possible (mostly genus- or species-) level identifications in the calculation of TL and TH indices weakened the relationships with toxic units. Tolerance values based on order- and family-level identifications of benthos for artificial substrate samples were more strongly correlated with toxic units than tolerance values for benthos from Ponar grabs. The ability of the toxic-units model to predict the other two components (i.e., laboratory-measured sediment toxicity and benthic community composition) of the Sediment Quality Triad (SQT) may obviate the need for the SQT in some situations.

Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton▿

PubMed Central

Eriksson, K. M.; Clarke, A. K.; Franzen, L.-G.; Kuylenstierna, M.; Martinez, K.; Blanck, H.

2009-01-01

This study analyzes psbA gene sequences, predicted D1 protein sequences, species relative abundance, and pollution-induced community tolerance in marine periphyton communities exposed to the antifouling compound Irgarol 1051. The mechanism of action of Irgarol is the inhibition of photosynthetic electron transport at photosystem II by binding to the D1 protein. The metagenome of the communities was used to produce clone libraries containing fragments of the psbA gene encoding the D1 protein. Community tolerance was quantified with a short-term test for the inhibition of photosynthesis. The communities were established in a continuous flow of natural seawater through microcosms with or without added Irgarol. The selection pressure from Irgarol resulted in an altered species composition and an inducted community tolerance to Irgarol. Moreover, there was a very high diversity in the psbA gene sequences in the periphyton, and the composition of psbA and D1 fragments within the communities was dramatically altered by increased Irgarol exposure. Even though tolerance to this type of compound in land plants often depends on a single amino acid substitution (Ser264→Gly) in the D1 protein, this was not the case for marine periphyton species. Instead, the tolerance mechanism likely involves increased degradation of D1. When we compared sequences from low and high Irgarol exposure, differences in nonconserved amino acids were found only in the so-called PEST region of D1, which is involved in regulating its degradation. Our results suggest that environmental contamination with Irgarol has led to selection for high-turnover D1 proteins in marine periphyton communities at the west coast of Sweden. PMID:19088321

Derivation of mean dose tolerances for new fractionation schemes and treatment modalities

NASA Astrophysics Data System (ADS)

Perkó, Zoltán; Bortfeld, Thomas; Hong, Theodore; Wolfgang, John; Unkelbach, Jan

2018-02-01

Avoiding toxicities in radiotherapy requires the knowledge of tolerable organ doses. For new, experimental fractionation schemes (e.g. hypofractionation) these are typically derived from traditional schedules using the biologically effective dose (BED) model. In this report we investigate the difficulties of establishing mean dose tolerances that arise since the mean BED depends on the entire spatial dose distribution, rather than on the dose level alone. A formula has been derived to establish mean physical dose constraints such that they are mean BED equivalent to a reference treatment scheme. This formula constitutes a modified BED equation where the influence of the spatial dose distribution is summarized in a single parameter, the dose shape factor. To quantify effects we analyzed 24 liver cancer patients for whom both proton and photon IMRT treatment plans were available. The results show that the standard BED equation—neglecting the spatial dose distribution—can overestimate mean dose tolerances for hypofractionated treatments by up to 20%. The shape difference between photon and proton dose distributions can cause 30-40% differences in mean physical dose for plans having identical mean BEDs. Converting hypofractionated, 5/15-fraction proton doses to mean BED equivalent photon doses in traditional 35-fraction regimens resulted in up to 10 Gy higher doses than applying the standard BED formula. The dose shape effect should be accounted for to avoid overestimation of mean dose tolerances, particularly when estimating constraints for hypofractionated regimens. Additionally, tolerances established for one treatment modality cannot necessarily be applied to other modalities with drastically different dose distributions, such as proton therapy. Last, protons may only allow marginal (5-10%) dose escalation if a fraction-size adjusted organ mean dose is constraining instead of a physical dose.

Mapping Uncertainty Due to Missing Data in the Global Ocean Health Index.

PubMed

Frazier, Melanie; Longo, Catherine; Halpern, Benjamin S

2016-01-01

Indicators are increasingly used to measure environmental systems; however, they are often criticized for failing to measure and describe uncertainty. Uncertainty is particularly difficult to evaluate and communicate in the case of composite indicators which aggregate many indicators of ecosystem condition. One of the ongoing goals of the Ocean Health Index (OHI) has been to improve our approach to dealing with missing data, which is a major source of uncertainty. Here we: (1) quantify the potential influence of gapfilled data on index scores from the 2015 global OHI assessment; (2) develop effective methods of tracking, quantifying, and communicating this information; and (3) provide general guidance for implementing gapfilling procedures for existing and emerging indicators, including regional OHI assessments. For the overall OHI global index score, the percent contribution of gapfilled data was relatively small (18.5%); however, it varied substantially among regions and goals. In general, smaller territorial jurisdictions and the food provision and tourism and recreation goals required the most gapfilling. We found the best approach for managing gapfilled data was to mirror the general framework used to organize, calculate, and communicate the Index data and scores. Quantifying gapfilling provides a measure of the reliability of the scores for different regions and components of an indicator. Importantly, this information highlights the importance of the underlying datasets used to calculate composite indicators and can inform and incentivize future data collection.

A gas-tracer injection for evaluating the fate of methane in a coastal plain stream: Degassing versus in-stream oxidation

USGS Publications Warehouse

Heilweil, Victor M.; Solomon, D. Kip; Darrah, Thomas H.; Gilmore, Troy E.; Genereux, David P.

2016-01-01

Methane emissions from streams and rivers have recently been recognized as an important component of global greenhouse budgets. Stream methane is lost as evasion to the atmosphere or in-stream methane oxidation. Previous studies have quantified evasion and oxidation with point-scale measurements. In this study, dissolved gases (methane, krypton) were injected into a coastal plain stream in North Carolina to quantify stream CH4 losses at the watershed scale. Stream-reach modeling yielded gas transfer and oxidation rate constants of 3.2 ± 0.5 and 0.5 ± 1.5 d–1, respectively, indicating a ratio of about 6:1. The resulting evasion and oxidation rates of 2.9 mmol m–2 d–1 and 1,140 nmol L–1 d–1, respectively, lie within ranges of published values. Similarly, the gas transfer velocity (K600) of 2.1 m d–1 is consistent with other gas tracer studies. This study illustrates the utility of dissolved-gas tracers for evaluating stream methane fluxes. In contrast to point measurements, this approach provides a larger watershed-scale perspective. Further work is needed to quantify the magnitude of these fluxes under varying conditions (e.g., stream temperature, nutrient load, gradient, flow rate) at regional and global scales before reliable bottom-up estimates of methane evasion can be determined at global scales.

Global rates of marine sulfate reduction and implications for sub-sea-floor metabolic activities

NASA Astrophysics Data System (ADS)

Bowles, Marshall W.; Mogollón, José M.; Kasten, Sabine; Zabel, Matthias; Hinrichs, Kai-Uwe

2014-05-01

Sulfate reduction is a globally important redox process in marine sediments, yet global rates are poorly quantified. We developed an artificial neural network trained with 199 sulfate profiles, constrained with geomorphological and geochemical maps to estimate global sulfate-reduction rate distributions. Globally, 11.3 teramoles of sulfate are reduced yearly (~15% of previous estimates), accounting for the oxidation of 12 to 29% of the organic carbon flux to the sea floor. Combined with global cell distributions in marine sediments, these results indicate a strong contrast in sub-sea-floor prokaryote habitats: In continental margins, global cell numbers in sulfate-depleted sediment exceed those in the overlying sulfate-bearing sediment by one order of magnitude, whereas in the abyss, most life occurs in oxic and/or sulfate-reducing sediments.

Experimental assessment of factors mediating the naturalization of a globally invasive tree on sandy coastal plains: a case study from Brazil

PubMed Central

Zimmermann, Thalita G.; Andrade, Antonio C. S.; Richardson, David M.

2016-01-01

As all naturalized species are potential invaders, it is important to better understand the determinants of naturalization of alien plants. This study sought to identify traits that enable the alien tree Casuarina equisetifolia to overcome barriers to survival and reproductive and to become naturalized on sandy coastal plains. Restinga vegetation in Brazil was used as a model system to conceptualize and quantify key stressors (high temperature, solar radiation, drought and salinity) which can limit the initial establishment of the plants. Experiments were conducted to evaluate the effects of these environmental factors on seed persistence in the soil (field), germination (laboratory), survival, growth, phenotypic plasticity and phenotypic integration (greenhouse). Results show that the expected viability of the seeds in the soil was 50 months. Seeds germinated in a similar way in constant and alternating temperatures (20–40 °C), except at 40 °C. Low light, and water and salt stresses reduced germination, but seeds recovered germination when stress diminished. Young plants did not tolerate water stress (<2 % of soil moisture) or deep shade. Growth was greater in sunny than in shady conditions. Although a low degree of phenotypic plasticity is important in habitats with multiple stress factors, this species exhibited high germination plasticity, although young plants showed low plasticity. The positive effect of phenotypic integration on plastic expression in the shade shows that in stressful environments traits that show greater phenotypic plasticity values may have significant phenotypic correlations with other characters, which is an important factor in the evolutionary ecology of this invasive species. Long-term seed persistence in the soil, broad germination requirements (temperature and light conditions) and the capacity to survive in a wide range of light intensity favours its naturalization. However, C. equisetifolia did not tolerate water stress and deep shade, which limit its potential to become naturalized on sandy coastal plain. PMID:27339050

Emphysema on Thoracic CT and Exercise Ventilatory Inefficiency in Mild-to-Moderate COPD.

PubMed

Jones, Joshua H; Zelt, Joel T; Hirai, Daniel M; Diniz, Camilla V; Zaza, Aida; O'Donnell, Denis E; Neder, J Alberto

2017-04-01

There is growing evidence that emphysema on thoracic computed tomography (CT) is associated with poor exercise tolerance in COPD patients with only mild-to-moderate airflow obstruction. We hypothesized that an excessive ventilatory response to exercise (ventilatory inefficiency) would underlie these abnormalities. In a prospective study, 19 patients (FEV 1 = 82 ± 13%, 12 Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 1) and 26 controls underwent an incremental exercise test. Ventilatory inefficiency was assessed by the ventilation ([Formula: see text]E)/CO 2 output ([Formula: see text]CO 2 ) nadir. Pulmonary blood flow (PBF) in a submaximal test was calculated by inert gas rebreathing. Emphysema was quantified as % of attenuation areas below 950 HU. Patients typically presented with centrilobular emphysema (76.8 ± 10.1% of total emphysema) in the upper lobes (upper/total lung ratio = 0.82 ± 0.04). They had lower peak oxygen uptake ([Formula: see text]O 2 ), higher [Formula: see text]E/[Formula: see text]CO 2 nadir, and greater dyspnea scores than controls (p < 0.05). Lower peak [Formula: see text]O 2 and worse dyspnea were found in patients with higher [Formula: see text]E/[Formula: see text]CO 2 nadirs (≥30). Patients had blunted increases in PBF from rest to iso-[Formula: see text]O 2 exercise (p < 0.05). Higher [Formula: see text]E/[Formula: see text]CO 2 nadir in COPD was associated with emphysema severity (r = 0.63) which, in turn, was related to reduced lung diffusing capacity (r = -0.72) and blunted changes in PBF from rest to exercise (r = -0.69) (p < 0.01). Ventilation "wasted" in emphysematous areas is associated with impaired exercise ventilatory efficiency in mild-to-moderate COPD. Exercise ventilatory inefficiency links structure (emphysema) and function (D L CO) to a key clinical outcome (poor exercise tolerance) in COPD patients with only modest spirometric abnormalities.

Experimental assessment of factors mediating the naturalization of a globally invasive tree on sandy coastal plains: a case study from Brazil.

PubMed

Zimmermann, Thalita G; Andrade, Antonio C S; Richardson, David M

2016-01-01

As all naturalized species are potential invaders, it is important to better understand the determinants of naturalization of alien plants. This study sought to identify traits that enable the alien tree Casuarina equisetifolia to overcome barriers to survival and reproductive and to become naturalized on sandy coastal plains. Restinga vegetation in Brazil was used as a model system to conceptualize and quantify key stressors (high temperature, solar radiation, drought and salinity) which can limit the initial establishment of the plants. Experiments were conducted to evaluate the effects of these environmental factors on seed persistence in the soil (field), germination (laboratory), survival, growth, phenotypic plasticity and phenotypic integration (greenhouse). Results show that the expected viability of the seeds in the soil was 50 months. Seeds germinated in a similar way in constant and alternating temperatures (20-40 °C), except at 40 °C. Low light, and water and salt stresses reduced germination, but seeds recovered germination when stress diminished. Young plants did not tolerate water stress (<2 % of soil moisture) or deep shade. Growth was greater in sunny than in shady conditions. Although a low degree of phenotypic plasticity is important in habitats with multiple stress factors, this species exhibited high germination plasticity, although young plants showed low plasticity. The positive effect of phenotypic integration on plastic expression in the shade shows that in stressful environments traits that show greater phenotypic plasticity values may have significant phenotypic correlations with other characters, which is an important factor in the evolutionary ecology of this invasive species. Long-term seed persistence in the soil, broad germination requirements (temperature and light conditions) and the capacity to survive in a wide range of light intensity favours its naturalization. However, C. equisetifolia did not tolerate water stress and deep shade, which limit its potential to become naturalized on sandy coastal plain. Published by Oxford University Press on behalf of the Annals of Botany Company.

Interdependency of Reactive Oxygen Species generating and scavenging system in salt sensitive and salt tolerant cultivars of rice.

PubMed

Kaur, Navdeep; Dhawan, Manish; Sharma, Isha; Pati, Pratap Kumar

2016-06-10

Salinity stress is a major constrain in the global rice production and hence serious efforts are being undertaken towards deciphering its remedial strategies. The comparative analysis of differential response of salt sensitive and salt tolerant lines is a judicious approach to obtain essential clues towards understanding the acquisition of salinity tolerance in rice plants. However, adaptation to salt stress is a fairly complex process and operates through different mechanisms. Among various mechanisms involved, the reactive oxygen species mediated salinity tolerance is believed to be critical as it evokes cascade of responses related to stress tolerance. In this background, the present paper for the first time evaluates the ROS generating and the scavenging system in tandem in both salt sensitive and salt tolerant cultivars of rice for getting better insight into salinity stress adaptation. Comparative analysis of ROS indicates the higher level of hydrogen peroxide (H2O2) and lower level of superoxide ions (O(2-)) in the salt tolerant as compared to salt sensitive cultivars. Specific activity of ROS generating enzyme, NADPH oxidase was also found to be more in the tolerant cultivars. Further, activities of various enzymes involved in enzymatic and non enzymatic antioxidant defence system were mostly higher in tolerant cultivars. The transcript level analysis of antioxidant enzymes were in alignment with the enzymatic activity. Other stress markers like proline were observed to be higher in tolerant varieties whereas, the level of malondialdehyde (MDA) equivalents and chlorophyll content were estimated to be more in sensitive. The present study showed significant differences in the level of ROS production and antioxidant enzymes activities among sensitive and tolerant cultivars, suggesting their possible role in providing natural salt tolerance to selected cultivars of rice. Our study demonstrates that the cellular machinery for ROS production and scavenging system works in an interdependent manner to offer better salt stress adaptation in rice. The present work further highlights that the elevated level of H2O2 which is considered as a key determinant for conferring salt stress tolerance to rice might have originated through an alternative route of photocatalytic activity of chlorophyll.

Detecting the differences in responses of stomatal conductance to moisture stresses between deciduous shrubs and Artemisia subshrubs.

PubMed

Gao, Qiong; Yu, Mei; Zhou, Chan

2013-01-01

Shrubs and subshrubs can tolerate wider ranges of moisture stresses in both soil and air than other plant life forms, and thus represent greater nonlinearity and uncertainty in ecosystem physiology. The objectives of this paper are to model shrub/subshrub stomatal conductance by synthesizing the field leaf gas exchanges data of 24 species in China, in order to detect the differences between deciduous shrubs and Artemisia subshrubs in their responses of stomatal conductance to changes in the moisture stresses. We revised a model of stomatal conductance by incorporating the tradeoff between xylem hydraulic efficiency and cavitation loss risk. We then fit the model at the three hierarchical levels: global (pooling all data as a single group), three functional groups (deciduous non-legume shrubs, deciduous legume shrubs, and subshrubs in Artemisia genus), and individual observations (species × sites). Bayesian inference with Markov Chain Monte Carlo method was applied to obtain the model parameters at the three levels. We found that the model at the level of functional groups is a significant improvement over that at the global level, indicating the significant differences in the stomatal behavior among the three functional groups. The differences in tolerance and sensitivities to changes in moisture stresses are the most evident between the shrubs and the subshrubs: The two shrub groups can tolerate much higher soil water stress than the subshrubs. The analysis at the observation level is also a significant improvement over that at the functional group level, indicating great variations within each group. Our analysis offered a clue for the equivocal issue of shrub encroachment into grasslands: While the invasion by the shrubs may be irreversible, the dominance of subshrubs, due to their lower resistance and tolerance to moisture stresses, may be put down by appropriate grassland management.

Rasagiline for mild cognitive impairment in Parkinson's disease: A placebo-controlled trial.

PubMed

Weintraub, Daniel; Hauser, Robert A; Elm, Jordan J; Pagan, Fernando; Davis, Matthew D; Choudhry, Azhar

2016-05-01

This study's aims were to determine the efficacy and tolerability of rasagiline, a selective monoamine oxidase inhibitor B, for PD patients with mild cognitive impairment. Patients on stable dopaminergic therapy were randomized to adjunct rasagiline 1 mg/day or placebo in this 24-week, double-blind, placebo-controlled, multisite study. The primary endpoint was mean change from baseline to week 24 on the Scales for Outcomes of Parkinson's Disease-Cognition total score. Key secondary measures included changes in cognition, activities of daily living, motor scores, and Clinical Global Impression of Change, as well as safety and tolerability measures. Of the 170 patients randomized, 151 (88.2%) completed the study. Change in Scales for Outcomes of Parkinson's Disease-Cognition scores were not significantly different in the rasagiline and placebo groups (adjusted mean: 1.6 [standard error {SE} = 0.5] vs. 0.8 [SE = 0.5] points; LS means difference = 0.8; 95% confidence interval: -0.48, 2.05; P = 0.22). There were no between-group differences in change in the MoCA (p=0.84) or Penn Daily Activities Questionnaire (P = 0.48) scores or in the distribution of Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change modified for mild cognitive impairment (P = 0.1). Changes in motor (UPDRS part III; P = 0.02) and activities of daily living (UPDRS part II; P < 0.001) scores favored rasagiline. Rasagiline was well tolerated; the most common adverse events in both groups were falls and dizziness. Rasagiline treatment in PD patients with mild cognitive impairment was not associated with cognitive improvement. Rasagiline did not worsen cognition, improved motor symptoms and activities of daily living, and was well tolerated in elderly cognitively impaired patients. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

Systems biology-based approaches toward understanding drought tolerance in food crops.

PubMed

Jogaiah, Sudisha; Govind, Sharathchandra Ramsandra; Tran, Lam-Son Phan

2013-03-01

Economically important crops, such as maize, wheat, rice, barley, and other food crops are affected by even small changes in water potential at important growth stages. Developing a comprehensive understanding of host response to drought requires a global view of the complex mechanisms involved. Research on drought tolerance has generally been conducted using discipline-specific approaches. However, plant stress response is complex and interlinked to a point where discipline-specific approaches do not give a complete global analysis of all the interlinked mechanisms. Systems biology perspective is needed to understand genome-scale networks required for building long-lasting drought resistance. Network maps have been constructed by integrating multiple functional genomics data with both model plants, such as Arabidopsis thaliana, Lotus japonicus, and Medicago truncatula, and various food crops, such as rice and soybean. Useful functional genomics data have been obtained from genome-wide comparative transcriptome and proteome analyses of drought responses from different crops. This integrative approach used by many groups has led to identification of commonly regulated signaling pathways and genes following exposure to drought. Combination of functional genomics and systems biology is very useful for comparative analysis of other food crops and has the ability to develop stable food systems worldwide. In addition, studying desiccation tolerance in resurrection plants will unravel how combination of molecular genetic and metabolic processes interacts to produce a resurrection phenotype. Systems biology-based approaches have helped in understanding how these individual factors and mechanisms (biochemical, molecular, and metabolic) "interact" spatially and temporally. Signaling network maps of such interactions are needed that can be used to design better engineering strategies for improving drought tolerance of important crop species.

Global Adoption of Genetically Modified (GM) Crops: Challenges for the Public Sector.

PubMed

Huesing, Joseph E; Andres, David; Braverman, Michael P; Burns, Andrea; Felsot, Allan S; Harrigan, George G; Hellmich, Richard L; Reynolds, Alan; Shelton, Anthony M; Jansen van Rijssen, Wilna; Morris, E Jane; Eloff, Jacobus N

2016-01-20

Advances in biotechnology continue to drive the development of a wide range of insect-protected, herbicide-tolerant, stress-tolerant, and nutritionally enhanced genetically modified (GM) crops, yet societal and public policy considerations may slow their commercialization. Such restrictions may disproportionately affect developing countries, as well as smaller entrepreneurial and public sector initiatives. The 2014 IUPAC International Congress of Pesticide Chemistry (San Francisco, CA, USA; August 2014) included a symposium on "Challenges Associated with Global Adoption of Agricultural Biotechnology" to review current obstacles in promoting GM crops. Challenges identified by symposium presenters included (i) poor public understanding of GM technology and the need for enhanced communication strategies, (ii) nonharmonized and prescriptive regulatory requirements, and (iii) limited experience with regulations and product development within some public sector programs. The need for holistic resistance management programs to enable the most effective use of insect-protected crops was also a point of emphasis. This paper provides details on the symposium discussion and provides background information that can be used in support of further adoption of beneficial GM crops. Overall, it emphasizes that global adoption of modern agricultural biotechnology has not only provided benefits to growers and consumers but has great potential to provide solutions to an increasing global population and diminishing agricultural land. This potential will be realized by continued scientific innovation, harmonized regulatory systems, and broader communication of the benefits of the high-yielding, disease-resistant, and nutritionally enhanced crops attainable through modern biotechnology.

The genetic makeup of a global barnyard millet germplasm collection

USDA-ARS?s Scientific Manuscript database

Barnyard millet (Echinochloa spp.) is an important crop for many smallholder farmers in southern and eastern Asia. It is valued for its drought tolerance, rapid maturation, and superior nutritional qualities. Despite these characteristics there are almost no genetic or genomic resources for this cro...

The physiology of mangrove trees with changing climate

USGS Publications Warehouse

Lovelock, Catherine E.; Krauss, Ken W.; Osland, Michael J.; Reef, Ruth; Ball, Marilyn C.; Meinzer, Frederick C.; Niinemets, Ülo

2016-01-01

Mangrove forests grow on saline, periodically flooded soils of the tropical and subtropical coasts. The tree species that comprise the mangrove are halophytes that have suites of traits that confer differing levels of tolerance of salinity, aridity, inundation and extremes of temperature. Here we review how climate change and elevated levels of atmospheric CO2 will influence mangrove forests. Tolerance of salinity and inundation in mangroves is associated with the efficient use of water for photosynthetic carbon gain which unpins anticipated gains in productivity with increasing levels of CO2. We review evidence of increases in productivity with increasing CO2, finding that enhancements in growth appear to be similar to trees in non-mangrove habitats and that gains in productivity with elevated CO2 are likely due to changes in biomass allocation. High levels of trait plasticity are observed in some mangrove species, which potentially facilitates their responses to climate change. Trait plasticity is associated with broad tolerance of salinity, aridity, low temperatures and nutrient availability. Because low temperatures and aridity place strong limits on mangrove growth at the edge of their current distribution, increasing temperatures over time and changing rainfall patterns are likely to have an important influence on the distribution of mangroves. We provide a global analysis based on plant traits and IPCC scenarios of changing temperature and aridity that indicates substantial global potential for mangrove expansion.

Augmented design and analysis of computer experiments: a novel tolerance embedded global optimization approach applied to SWIR hyperspectral illumination design.

PubMed

Keresztes, Janos C; John Koshel, R; D'huys, Karlien; De Ketelaere, Bart; Audenaert, Jan; Goos, Peter; Saeys, Wouter

2016-12-26

A novel meta-heuristic approach for minimizing nonlinear constrained problems is proposed, which offers tolerance information during the search for the global optimum. The method is based on the concept of design and analysis of computer experiments combined with a novel two phase design augmentation (DACEDA), which models the entire merit space using a Gaussian process, with iteratively increased resolution around the optimum. The algorithm is introduced through a series of cases studies with increasing complexity for optimizing uniformity of a short-wave infrared (SWIR) hyperspectral imaging (HSI) illumination system (IS). The method is first demonstrated for a two-dimensional problem consisting of the positioning of analytical isotropic point sources. The method is further applied to two-dimensional (2D) and five-dimensional (5D) SWIR HSI IS versions using close- and far-field measured source models applied within the non-sequential ray-tracing software FRED, including inherent stochastic noise. The proposed method is compared to other heuristic approaches such as simplex and simulated annealing (SA). It is shown that DACEDA converges towards a minimum with 1 % improvement compared to simplex and SA, and more importantly requiring only half the number of simulations. Finally, a concurrent tolerance analysis is done within DACEDA for to the five-dimensional case such that further simulations are not required.

Global transcriptome analysis of Halolamina sp. to decipher the salt tolerance in extremely halophilic archaea.

PubMed

Kurt-Kızıldoğan, Aslıhan; Abanoz, Büşra; Okay, Sezer

2017-02-15

Extremely halophilic archaea survive in the hypersaline environments such as salt lakes or salt mines. Therefore, these microorganisms are good sources to investigate the molecular mechanisms underlying the tolerance to high salt concentrations. In this study, a global transcriptome analysis was conducted in an extremely halophilic archaeon, Halolamina sp. YKT1, isolated from a salt mine in Turkey. A comparative RNA-seq analysis was performed using YKT1 isolate grown either at 2.7M NaCl or 5.5M NaCl concentrations. A total of 2149 genes were predicted to be up-regulated and 1638 genes were down-regulated in the presence of 5.5M NaCl. The salt tolerance of Halolamina sp. YKT1 involves the up-regulation of genes related with membrane transporters, CRISPR-Cas systems, osmoprotectant solutes, oxidative stress proteins, and iron metabolism. On the other hand, the genes encoding the proteins involved in DNA replication, transcription, translation, mismatch and nucleotide excision repair were down-regulated. The RNA-seq data were verified for seven up-regulated genes as well as six down-regulated genes via qRT-PCR analysis. This comprehensive transcriptome analysis showed that the halophilic archaeon canalizes its energy towards keeping the intracellular osmotic balance minimizing the production of nucleic acids and peptides. Copyright © 2016 Elsevier B.V. All rights reserved.

Improvement of Lead Tolerance of Saccharomyces cerevisiae by Random Mutagenesis of Transcription Regulator SPT3.

PubMed

Zhu, Liying; Gao, Shan; Zhang, Hongman; Huang, He; Jiang, Ling

2018-01-01

Bioremediation of heavy metal pollution with biomaterials such as bacteria and fungi usually suffer from limitations because of microbial sensitivity to high concentration of heavy metals. Herein, we adopted a novel random mutagenesis technique called RAISE to manipulate the transcription regulator SPT3 of Saccharomyces cerevisiae to improve cell lead tolerance. The best strain Mutant VI was selected from the random mutagenesis libraries on account of the growth performance, with higher specific growth rate than the control strain (0.068 vs. 0.040 h -1 ) at lead concentration as high as 1.8 g/L. Combined with the transcriptome analysis of S. cerevisiae, expressing the SPT3 protein was performed to make better sense of the global regulatory effects of SPT3. The data analysis revealed that 57 of S. cerevisiae genes were induced and 113 genes were suppressed, ranging from those for trehalose synthesis, carbon metabolism, and nucleotide synthesis to lead resistance. Especially, the accumulation of intracellular trehalose in S. cerevisiae under certain conditions of stress is considered important to lead resistance. The above results represented that SPT3 was acted as global transcription regulator in the exponential phase of strain and accordingly improved heavy metal tolerance in the heterologous host S. cerevisiae. The present study provides a route to complex phenotypes that are not readily accessible by traditional methods.

SpxA1 Involved in Hydrogen Peroxide Production, Stress Tolerance and Endocarditis Virulence in Streptococcus sanguinis

PubMed Central

Chen, Lei; Ge, Xiuchun; Wang, Xiaojing; Patel, Jenishkumar R.; Xu, Ping

2012-01-01

Streptococcus sanguinis is one of the most common agents of infective endocarditis. Spx proteins are a group of global regulators that negatively or positively control global transcription initiation. In this study, we characterized the spxA1 gene in S. sanguinis SK36. The spxA1 null mutant displayed opaque colony morphology, reduced hydrogen peroxide (H2O2) production, and reduced antagonistic activity against Streptococcus mutans UA159 relative to the wild type strain. The ΔspxA1 mutant also demonstrated decreased tolerance to high temperature, acidic and oxidative stresses. Further analysis revealed that ΔspxA1 also exhibited a ∼5-fold reduction in competitiveness in an animal model of endocarditis. Microarray studies indicated that expression of several oxidative stress genes was downregulated in the ΔspxA1 mutant. The expression of spxB and nox was significantly decreased in the ΔspxA1 mutant compared with the wild type. These results indicate that spxA1 plays a major role in H2O2 production, stress tolerance and endocarditis virulence in S. sanguinis SK36. The second spx gene, spxA2, was also found in S. sanguinis SK36. The spxA2 null mutant was found to be defective for growth under normal conditions and showed sensitivity to high temperature, acidic and oxidative stresses. PMID:22768210

SpxA1 involved in hydrogen peroxide production, stress tolerance and endocarditis virulence in Streptococcus sanguinis.

PubMed

Chen, Lei; Ge, Xiuchun; Wang, Xiaojing; Patel, Jenishkumar R; Xu, Ping

2012-01-01

Streptococcus sanguinis is one of the most common agents of infective endocarditis. Spx proteins are a group of global regulators that negatively or positively control global transcription initiation. In this study, we characterized the spxA1 gene in S. sanguinis SK36. The spxA1 null mutant displayed opaque colony morphology, reduced hydrogen peroxide (H(2)O(2)) production, and reduced antagonistic activity against Streptococcus mutans UA159 relative to the wild type strain. The ΔspxA1 mutant also demonstrated decreased tolerance to high temperature, acidic and oxidative stresses. Further analysis revealed that ΔspxA1 also exhibited a ∼5-fold reduction in competitiveness in an animal model of endocarditis. Microarray studies indicated that expression of several oxidative stress genes was downregulated in the ΔspxA1 mutant. The expression of spxB and nox was significantly decreased in the ΔspxA1 mutant compared with the wild type. These results indicate that spxA1 plays a major role in H(2)O(2) production, stress tolerance and endocarditis virulence in S. sanguinis SK36. The second spx gene, spxA2, was also found in S. sanguinis SK36. The spxA2 null mutant was found to be defective for growth under normal conditions and showed sensitivity to high temperature, acidic and oxidative stresses.

Methyl-Donor and Cofactor Nutrient Intakes in the First 2–3 Years and Global DNA Methylation at Age 4: A Prospective Cohort Study

PubMed Central

Taylor, Rachael M.; Smith, Roger; Collins, Clare E.; Mossman, David; Wong-Brown, Michelle W.; Chan, Eng-Cheng; Evans, Tiffany-Jane; Attia, John R.; Smith, Tenele; Butler, Trent

2018-01-01

Background: During the early postnatal period, the impact of nutrition on DNA methylation has not been well studied in humans. The aim was to quantify the relationship between one-carbon metabolism nutrient intake during the first three years of life and global DNA methylation levels at four years. Design: Childhood dietary intake was assessed using infant feeding questionnaires, food frequency questionnaires, 4-day weighed food records and 24-h food records. The dietary records were used to estimate the intake of methionine, folate, vitamins B2, B6 and B12 and choline. The accumulative nutrient intake specific rank from three months to three years of age was used for analysis. Global DNA methylation (%5-methyl cytosines (%5-mC)) was measured in buccal cells at four years of age, using an enzyme-linked immunosorbent assay (ELISA) commercial kit. Linear regression models were used to quantify the statistical relationships. Results: Data were collected from 73 children recruited from the Women and their Children’s Health (WATCH) study. No association was found between one-carbon metabolism nutrient intake and global DNA methylation levels (P 0.05). Global DNA methylation levels in males were significantly higher than in females (median %5-mC: 1.82 vs. 1.03, males and females respectively, (P 0.05)). Conclusion: No association was found between the intake of one-carbon metabolism nutrients during the early postnatal period and global DNA methylation levels at age four years. Higher global DNA methylation levels in males warrants further investigation. PMID:29495543

Advanced Taste Sensors Based on Artificial Lipids with Global Selectivity to Basic Taste Qualities and High Correlation to Sensory Scores

PubMed Central

Kobayashi, Yoshikazu; Habara, Masaaki; Ikezazki, Hidekazu; Chen, Ronggang; Naito, Yoshinobu; Toko, Kiyoshi

2010-01-01

Effective R&D and strict quality control of a broad range of foods, beverages, and pharmaceutical products require objective taste evaluation. Advanced taste sensors using artificial-lipid membranes have been developed based on concepts of global selectivity and high correlation with human sensory score. These sensors respond similarly to similar basic tastes, which they quantify with high correlations to sensory score. Using these unique properties, these sensors can quantify the basic tastes of saltiness, sourness, bitterness, umami, astringency and richness without multivariate analysis or artificial neural networks. This review describes all aspects of these taste sensors based on artificial lipid, ranging from the response principle and optimal design methods to applications in the food, beverage, and pharmaceutical markets. PMID:22319306

Breeding approaches and genomics technologies to increase crop yield under low-temperature stress.

PubMed

Jha, Uday Chand; Bohra, Abhishek; Jha, Rintu

2017-01-01

Improved knowledge about plant cold stress tolerance offered by modern omics technologies will greatly inform future crop improvement strategies that aim to breed cultivars yielding substantially high under low-temperature conditions. Alarmingly rising temperature extremities present a substantial impediment to the projected target of 70% more food production by 2050. Low-temperature (LT) stress severely constrains crop production worldwide, thereby demanding an urgent yet sustainable solution. Considerable research progress has been achieved on this front. Here, we review the crucial cellular and metabolic alterations in plants that follow LT stress along with the signal transduction and the regulatory network describing the plant cold tolerance. The significance of plant genetic resources to expand the genetic base of breeding programmes with regard to cold tolerance is highlighted. Also, the genetic architecture of cold tolerance trait as elucidated by conventional QTL mapping and genome-wide association mapping is described. Further, global expression profiling techniques including RNA-Seq along with diverse omics platforms are briefly discussed to better understand the underlying mechanism and prioritize the candidate gene (s) for downstream applications. These latest additions to breeders' toolbox hold immense potential to support plant breeding schemes that seek development of LT-tolerant cultivars. High-yielding cultivars endowed with greater cold tolerance are urgently required to sustain the crop yield under conditions severely challenged by low-temperature.

The determinants of leaf turgor loss point and prediction of drought tolerance of species and biomes: a global meta-analysis.

PubMed

Bartlett, Megan K; Scoffoni, Christine; Sack, Lawren

2012-05-01

Increasing drought is one of the most critical challenges facing species and ecosystems worldwide, and improved theory and practices are needed for quantification of species tolerances. Leaf water potential at turgor loss, or wilting (π(tlp) ), is classically recognised as a major physiological determinant of plant water stress response. However, the cellular basis of π(tlp) and its importance for predicting ecological drought tolerance have been controversial. A meta-analysis of 317 species from 72 studies showed that π(tlp) was strongly correlated with water availability within and across biomes, indicating power for anticipating drought responses. We derived new equations giving both π(tlp) and relative water content at turgor loss point (RWC(tlp) ) as explicit functions of osmotic potential at full turgor (π(o) ) and bulk modulus of elasticity (ε). Sensitivity analyses and meta-analyses showed that π(o) is the major driver of π(tlp) . In contrast, ε plays no direct role in driving drought tolerance within or across species, but sclerophylly and elastic adjustments act to maintain RWC(tlp,) preventing cell dehydration, and additionally protect against nutrient, mechanical and herbivory stresses independent of drought tolerance. These findings clarify biogeographic trends and the underlying basis of drought tolerance parameters with applications in comparative assessments of species and ecosystems worldwide. © 2012 Blackwell Publishing Ltd/CNRS.

Linking regional stakeholder scenarios and shared socioeconomic pathways: Quantified West African food and climate futures in a global context.

PubMed

Palazzo, Amanda; Vervoort, Joost M; Mason-D'Croz, Daniel; Rutting, Lucas; Havlík, Petr; Islam, Shahnila; Bayala, Jules; Valin, Hugo; Kadi Kadi, Hamé Abdou; Thornton, Philip; Zougmore, Robert

2017-07-01

The climate change research community's shared socioeconomic pathways (SSPs) are a set of alternative global development scenarios focused on mitigation of and adaptation to climate change. To use these scenarios as a global context that is relevant for policy guidance at regional and national levels, they have to be connected to an exploration of drivers and challenges informed by regional expertise. In this paper, we present scenarios for West Africa developed by regional stakeholders and quantified using two global economic models, GLOBIOM and IMPACT, in interaction with stakeholder-generated narratives and scenario trends and SSP assumptions. We present this process as an example of linking comparable scenarios across levels to increase coherence with global contexts, while presenting insights about the future of agriculture and food security under a range of future drivers including climate change. In these scenarios, strong economic development increases food security and agricultural development. The latter increases crop and livestock productivity leading to an expansion of agricultural area within the region while reducing the land expansion burden elsewhere. In the context of a global economy, West Africa remains a large consumer and producer of a selection of commodities. However, the growth in population coupled with rising incomes leads to increases in the region's imports. For West Africa, climate change is projected to have negative effects on both crop yields and grassland productivity, and a lack of investment may exacerbate these effects. Linking multi-stakeholder regional scenarios to the global SSPs ensures scenarios that are regionally appropriate and useful for policy development as evidenced in the case study, while allowing for a critical link to global contexts.

Ozone Production in Global Tropospheric Models: Quantifying Errors due to Grid Resolution

NASA Astrophysics Data System (ADS)

Wild, O.; Prather, M. J.

2005-12-01

Ozone production in global chemical models is dependent on model resolution because ozone chemistry is inherently nonlinear, the timescales for chemical production are short, and precursors are artificially distributed over the spatial scale of the model grid. In this study we examine the sensitivity of ozone, its precursors, and its production to resolution by running a global chemical transport model at four different resolutions between T21 (5.6° × 5.6°) and T106 (1.1° × 1.1°) and by quantifying the errors in regional and global budgets. The sensitivity to vertical mixing through the parameterization of boundary layer turbulence is also examined. We find less ozone production in the boundary layer at higher resolution, consistent with slower chemical production in polluted emission regions and greater export of precursors. Agreement with ozonesonde and aircraft measurements made during the NASA TRACE-P campaign over the Western Pacific in spring 2001 is consistently better at higher resolution. We demonstrate that the numerical errors in transport processes at a given resolution converge geometrically for a tracer at successively higher resolutions. The convergence in ozone production on progressing from T21 to T42, T63 and T106 resolution is likewise monotonic but still indicates large errors at 120~km scales, suggesting that T106 resolution is still too coarse to resolve regional ozone production. Diagnosing the ozone production and precursor transport that follow a short pulse of emissions over East Asia in springtime allows us to quantify the impacts of resolution on both regional and global ozone. Production close to continental emission regions is overestimated by 27% at T21 resolution, by 13% at T42 resolution, and by 5% at T106 resolution, but subsequent ozone production in the free troposphere is less significantly affected.

Global tropospheric ozone modeling: Quantifying errors due to grid resolution

NASA Astrophysics Data System (ADS)

Wild, Oliver; Prather, Michael J.

2006-06-01

Ozone production in global chemical models is dependent on model resolution because ozone chemistry is inherently nonlinear, the timescales for chemical production are short, and precursors are artificially distributed over the spatial scale of the model grid. In this study we examine the sensitivity of ozone, its precursors, and its production to resolution by running a global chemical transport model at four different resolutions between T21 (5.6° × 5.6°) and T106 (1.1° × 1.1°) and by quantifying the errors in regional and global budgets. The sensitivity to vertical mixing through the parameterization of boundary layer turbulence is also examined. We find less ozone production in the boundary layer at higher resolution, consistent with slower chemical production in polluted emission regions and greater export of precursors. Agreement with ozonesonde and aircraft measurements made during the NASA TRACE-P campaign over the western Pacific in spring 2001 is consistently better at higher resolution. We demonstrate that the numerical errors in transport processes on a given resolution converge geometrically for a tracer at successively higher resolutions. The convergence in ozone production on progressing from T21 to T42, T63, and T106 resolution is likewise monotonic but indicates that there are still large errors at 120 km scales, suggesting that T106 resolution is too coarse to resolve regional ozone production. Diagnosing the ozone production and precursor transport that follow a short pulse of emissions over east Asia in springtime allows us to quantify the impacts of resolution on both regional and global ozone. Production close to continental emission regions is overestimated by 27% at T21 resolution, by 13% at T42 resolution, and by 5% at T106 resolution. However, subsequent ozone production in the free troposphere is not greatly affected. We find that the export of short-lived precursors such as NOx by convection is overestimated at coarse resolution.

Model estimates of net primary productivity, evaportranspiration, and water use efficiency in the terrestrial ecosystems of the southern United States

Treesearch

Hanqin Tian; Guangsheng Chen; Mingliang Liu; Chi Zhang; Ge Sun; Chaoqun Lu; Xiaofeng Xu; Wei Ren; Shufen Pan; Arthur Chappelka

2010-01-01

The effects of global change on ecosystem productivity and water resources in the southern United States (SUS), a traditionally ‘water-rich’ region and the ‘timber basket’ of the country, are not well quantified. We carried out several simulation experiments to quantify ecosystem net primary productivity (NPP), evapotranspiration (ET)...

Pre-damage biomass allocation and not invasiveness predicts tolerance to damage in seedlings of woody species in Hawaii.

PubMed

Lurie, Matthew H; Barton, Kasey E; Daehler, Curtis C

2017-12-01

Plant-herbivore interactions have been predicted to play a fundamental role in plant invasions, although support for this assertion from previous research is mixed. While plants may escape from specialist herbivores in their introduced ranges, herbivory from generalists is common. Tolerance traits may allow non-native plants to mitigate the negative consequences of generalist herbivory that they cannot avoid in their introduced range. Here we address whether tolerance to herbivory, quantified as survival and compensatory growth, is associated with plant invasion success in Hawaii and investigate traits that may enhance tolerance in seedlings, the life stage most susceptible to herbivory. In a greenhouse experiment, we measured seedling tolerance to simulated herbivory through mechanical damage (50% leaf removal) of 16 non-native woody plant species differing in invasion status (invasive vs. non-invasive). Seedlings were grown for 2 weeks following damage and analyzed for biomass to determine whether damaged plants could fully compensate for the lost leaf tissue. Over 99% of all seedlings survived defoliation. Although species varied significantly in their levels of compensation, there was no consistent difference between invasive and non-invasive species. Seedlings of 11 species undercompensated and remained substantially smaller than control seedlings 2 weeks after damage; four species were close to compensating, while one species overcompensated. Across species, compensation was positively associated with an increased investment in potential storage reserves, specifically cotyledons and roots, suggesting that these organs provide resources that help seedlings re-grow following damage. Our results add to a growing consensus that pre-damage growth patterns determine tolerance to damage, even in young seedlings which have relatively low biomass. The lack of higher tolerance in highly invasive species may suggest that invaders overcome herbivory barriers to invasion in other ways, such as resistance traits, or that herbivory does not play an important role in the seedling invasion dynamics of these woody species in Hawaii. © 2017 by the Ecological Society of America.

Modeling OPC complexity for design for manufacturability

NASA Astrophysics Data System (ADS)

Gupta, Puneet; Kahng, Andrew B.; Muddu, Swamy; Nakagawa, Sam; Park, Chul-Hong

2005-11-01

Increasing design complexity in sub-90nm designs results in increased mask complexity and cost. Resolution enhancement techniques (RET) such as assist feature addition, phase shifting (attenuated PSM) and aggressive optical proximity correction (OPC) help in preserving feature fidelity in silicon but increase mask complexity and cost. Data volume increase with rise in mask complexity is becoming prohibitive for manufacturing. Mask cost is determined by mask write time and mask inspection time, which are directly related to the complexity of features printed on the mask. Aggressive RET increase complexity by adding assist features and by modifying existing features. Passing design intent to OPC has been identified as a solution for reducing mask complexity and cost in several recent works. The goal of design-aware OPC is to relax OPC tolerances of layout features to minimize mask cost, without sacrificing parametric yield. To convey optimal OPC tolerances for manufacturing, design optimization should drive OPC tolerance optimization using models of mask cost for devices and wires. Design optimization should be aware of impact of OPC correction levels on mask cost and performance of the design. This work introduces mask cost characterization (MCC) that quantifies OPC complexity, measured in terms of fracture count of the mask, for different OPC tolerances. MCC with different OPC tolerances is a critical step in linking design and manufacturing. In this paper, we present a MCC methodology that provides models of fracture count of standard cells and wire patterns for use in design optimization. MCC cannot be performed by designers as they do not have access to foundry OPC recipes and RET tools. To build a fracture count model, we perform OPC and fracturing on a limited set of standard cells and wire configurations with all tolerance combinations. Separately, we identify the characteristics of the layout that impact fracture count. Based on the fracture count (FC) data from OPC and mask data preparation runs, we build models of FC as function of OPC tolerances and layout parameters.

Structural equation models to estimate risk of infection and tolerance to bovine mastitis.

PubMed

Detilleux, Johann; Theron, Léonard; Duprez, Jean-Noël; Reding, Edouard; Humblet, Marie-France; Planchon, Viviane; Delfosse, Camille; Bertozzi, Carlo; Mainil, Jacques; Hanzen, Christian

2013-03-06

One method to improve durably animal welfare is to select, as reproducers, animals with the highest ability to resist or tolerate infection. To do so, it is necessary to distinguish direct and indirect mechanisms of resistance and tolerance because selection on these traits is believed to have different epidemiological and evolutionary consequences. We propose structural equation models with latent variables (1) to quantify the latent risk of infection and to identify, among the many potential mediators of infection, the few ones that influence it significantly and (2) to estimate direct and indirect levels of tolerance of animals infected naturally with pathogens. We applied the method to two surveys of bovine mastitis in the Walloon region of Belgium, in which we recorded herd management practices, mastitis frequency, and results of bacteriological analyses of milk samples. Structural equation models suggested that, among more than 35 surveyed herd characteristics, only nine (age, addition of urea in the rations, treatment of subclinical mastitis, presence of dirty liner, cows with hyperkeratotic teats, machine stripping, pre- and post-milking teat disinfection, and housing of milking cows in cubicles) were directly and significantly related to a latent measure of bovine mastitis, and that treatment of subclinical mastitis was involved in the pathway between post-milking teat disinfection and latent mastitis. These models also allowed the separation of direct and indirect effects of bacterial infection on milk productivity. Results suggested that infected cows were tolerant but not resistant to mastitis pathogens. We revealed the advantages of structural equation models, compared to classical models, for dissecting measurements of resistance and tolerance to infectious diseases, here bovine mastitis. Using our method, we identified nine major risk factors that were directly associated with an increased risk of mastitis and suggested that cows were tolerant but not resistant to mastitis. Selection should aim at improved resistance to infection by mastitis pathogens, although further investigations are needed due to the limitations of the data used in this study.

Experimental Evolution of UV-C Radiation Tolerance: Emergence of Adaptive and Non-Adaptive Traits in Escherichia coli Under Differing Flux Regimes

NASA Astrophysics Data System (ADS)

Moffet, A.; Okansinski, A.; Sloan, C.; Grace, J. M.; Paulino-Lima, I. G.; Gentry, D.; Rothschild, L. J.; Camps, M.

2014-12-01

High-energy ultraviolet (UV-C) radiation is a significant challenge to life in environments such as high altitude areas, the early Earth, the Martian surface, and space. As UV-C exposure is both a selection pressure and a mutagen, adaptation dynamics in such environments include a high rate of change in both tolerance-related and non-tolerance-related genes, as well changes in linkages between the resulting traits. Determining the relationship between the intensity and duration of the UV-C exposure, mutation rate, and emergence of UV-C resistance will inform our understanding of both the emergence of radiation-related extremophily in natural environments and the optimal strategies for generating artificial extremophiles. In this study, we iteratively exposed an Escherichia colistrain to UV-C radiation of two different fluxes, 3.3 J/m^2/s for 6 seconds and 0.5 J/m^2/s for 40 seconds, with the same overall fluence of 20 J/m^2. After each iteration, cells from each exposure regime were assayed for increased UV-C tolerance as an adaptive trait. The exposed cells carried a plasmid bearing a TEM beta-lactamase gene, which in the absence of antibiotic treatment is a neutral reporter for mutagenesis. Sequencing of this gene allowed us to determine the baseline mutation frequency for each flux. As an additional readout for adaptation, the presence of extended-spectrum beta-lactamase mutations was tested by plating UV-exposed cultures in cefotaxime plates. We observed an increase of approximately one-million-fold in UV-C tolerance over seven iterations; no significant difference between the two fluxes was found. Future work will focus on identifying the genomic changes responsible for the change in UV-C tolerance; determining the mechanisms of the emerged UV-C tolerance; and performing competition experiments between the iteration strains to quantify fitness tradeoffs resulting from UV-C adaptation.

Active and passive heat stress similarly compromise tolerance to a simulated hemorrhagic challenge.

PubMed

Pearson, J; Lucas, R A I; Schlader, Z J; Zhao, J; Gagnon, D; Crandall, C G

2014-10-01

Passive heat stress increases core and skin temperatures and reduces tolerance to simulated hemorrhage (lower body negative pressure; LBNP). We tested whether exercise-induced heat stress reduces LBNP tolerance to a greater extent relative to passive heat stress, when skin and core temperatures are similar. Eight participants (6 males, 32 ± 7 yr, 176 ± 8 cm, 77.0 ± 9.8 kg) underwent LBNP to presyncope on three separate and randomized occasions: 1) passive heat stress, 2) exercise in a hot environment (40°C) where skin temperature was moderate (36°C, active 36), and 3) exercise in a hot environment (40°C) where skin temperature was matched relative to that achieved during passive heat stress (∼38°C, active 38). LBNP tolerance was quantified using the cumulative stress index (CSI). Before LBNP, increases in core temperature from baseline were not different between trials (1.18 ± 0.20°C; P > 0.05). Also before LBNP, mean skin temperature was similar between passive heat stress (38.2 ± 0.5°C) and active 38 (38.2 ± 0.8°C; P = 0.90) trials, whereas it was reduced in the active 36 trial (36.6 ± 0.5°C; P ≤ 0.05 compared with passive heat stress and active 38). LBNP tolerance was not different between passive heat stress and active 38 trials (383 ± 223 and 322 ± 178 CSI, respectively; P = 0.12), but both were similarly reduced relative to active 36 (516 ± 147 CSI, both P ≤ 0.05). LBNP tolerance is not different between heat stresses induced either passively or by exercise in a hot environment when skin temperatures are similarly elevated. However, LBNP tolerance is influenced by the magnitude of the elevation in skin temperature following exercise induced heat stress. Copyright © 2014 the American Physiological Society.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perko, Z; Bortfeld, T; Hong, T

Purpose: The safe use of radiotherapy requires the knowledge of tolerable organ doses. For experimental fractionation schemes (e.g. hypofractionation) these are typically extrapolated from traditional fractionation schedules using the Biologically Effective Dose (BED) model. This work demonstrates that using the mean dose in the standard BED equation may overestimate tolerances, potentially leading to unsafe treatments. Instead, extrapolation of mean dose tolerances should take the spatial dose distribution into account. Methods: A formula has been derived to extrapolate mean physical dose constraints such that they are mean BED equivalent. This formula constitutes a modified BED equation where the influence of themore » spatial dose distribution is summarized in a single parameter, the dose shape factor. To quantify effects we analyzed 14 liver cancer patients previously treated with proton therapy in 5 or 15 fractions, for whom also photon IMRT plans were available. Results: Our work has two main implications. First, in typical clinical plans the dose distribution can have significant effects. When mean dose tolerances are extrapolated from standard fractionation towards hypofractionation they can be overestimated by 10–15%. Second, the shape difference between photon and proton dose distributions can cause 30–40% differences in mean physical dose for plans having the same mean BED. The combined effect when extrapolating proton doses to mean BED equivalent photon doses in traditional 35 fraction regimens resulted in up to 7–8 Gy higher doses than when applying the standard BED formula. This can potentially lead to unsafe treatments (in 1 of the 14 analyzed plans the liver mean dose was above its 32 Gy tolerance). Conclusion: The shape effect should be accounted for to avoid unsafe overestimation of mean dose tolerances, particularly when estimating constraints for hypofractionated regimens. In addition, tolerances established for a given treatment modality cannot necessarily be applied to other modalities with drastically different dose distributions.« less

Quantifying the Value of Downscaled Climate Model Information for Adaptation Decisions: When is Downscaling a Smart Decision?

NASA Astrophysics Data System (ADS)

Terando, A. J.; Wootten, A.; Eaton, M. J.; Runge, M. C.; Littell, J. S.; Bryan, A. M.; Carter, S. L.

2015-12-01

Two types of decisions face society with respect to anthropogenic climate change: (1) whether to enact a global greenhouse gas abatement policy, and (2) how to adapt to the local consequences of current and future climatic changes. The practice of downscaling global climate models (GCMs) is often used to address (2) because GCMs do not resolve key features that will mediate global climate change at the local scale. In response, the development of downscaling techniques and models has accelerated to aid decision makers seeking adaptation guidance. However, quantifiable estimates of the value of information are difficult to obtain, particularly in decision contexts characterized by deep uncertainty and low system-controllability. Here we demonstrate a method to quantify the additional value that decision makers could expect if research investments are directed towards developing new downscaled climate projections. As a proof of concept we focus on a real-world management problem: whether to undertake assisted migration for an endangered tropical avian species. We also take advantage of recently published multivariate methods that account for three vexing issues in climate impacts modeling: maximizing climate model quality information, accounting for model dependence in ensembles of opportunity, and deriving probabilistic projections. We expand on these global methods by including regional (Caribbean Basin) and local (Puerto Rico) domains. In the local domain, we test whether a high resolution (2km) dynamically downscaled GCM reduces the multivariate error estimate compared to the original coarse-scale GCM. Initial tests show little difference between the downscaled and original GCM multivariate error. When propagated through to a species population model, the Value of Information analysis indicates that the expected utility that would accrue to the manager (and species) if this downscaling were completed may not justify the cost compared to alternative actions.

The effects of spatial heterogeneity and subsurface lateral transfer on evapotranspiration estimates in large scale Earth system models

NASA Astrophysics Data System (ADS)

Rouholahnejad, E.; Fan, Y.; Kirchner, J. W.; Miralles, D. G.

2017-12-01

Most Earth system models (ESM) average over considerable sub-grid heterogeneity in land surface properties, and overlook subsurface lateral flow. This could potentially bias evapotranspiration (ET) estimates and has implications for future temperature predictions, since overestimations in ET imply greater latent heat fluxes and potential underestimation of dry and warm conditions in the context of climate change. Here we quantify the bias in evaporation estimates that may arise from the fact that ESMs average over considerable heterogeneity in surface properties, and also neglect lateral transfer of water across the heterogeneous landscapes at global scale. We use a Budyko framework to express ET as a function of P and PET to derive simple sub-grid closure relations that quantify how spatial heterogeneity and lateral transfer could affect average ET as seen from the atmosphere. We show that averaging over sub-grid heterogeneity in P and PET, as typical Earth system models do, leads to overestimation of average ET. Our analysis at global scale shows that the effects of sub-grid heterogeneity will be most pronounced in steep mountainous areas where the topographic gradient is high and where P is inversely correlated with PET across the landscape. In addition, we use the Total Water Storage (TWS) anomaly estimates from the Gravity Recovery and Climate Experiment (GRACE) remote sensing product and assimilate it into the Global Land Evaporation Amsterdam Model (GLEAM) to correct for existing free drainage lower boundary condition in GLEAM and quantify whether, and how much, accounting for changes in terrestrial storage can improve the simulation of soil moisture and regional ET fluxes at global scale.

EEG slow waves in traumatic brain injury: Convergent findings in mouse and man

PubMed Central

Modarres, Mo; Kuzma, Nicholas N.; Kretzmer, Tracy; Pack, Allan I.; Lim, Miranda M.

2016-01-01

Objective Evidence from previous studies suggests that greater sleep pressure, in the form of EEG-based slow waves, accumulates in specific brain regions that are more active during prior waking experience. We sought to quantify the number and coherence of EEG slow waves in subjects with mild traumatic brain injury (mTBI). Methods We developed a method to automatically detect individual slow waves in each EEG channel, and validated this method using simulated EEG data. We then used this method to quantify EEG-based slow waves during sleep and wake states in both mouse and human subjects with mTBI. A modified coherence index that accounts for information from multiple channels was calculated as a measure of slow wave synchrony. Results Brain-injured mice showed significantly higher theta:alpha amplitude ratios and significantly more slow waves during spontaneous wakefulness and during prolonged sleep deprivation, compared to sham-injured control mice. Human subjects with mTBI showed significantly higher theta:beta amplitude ratios and significantly more EEG slow waves while awake compared to age-matched control subjects. We then quantified the global coherence index of slow waves across several EEG channels in human subjects. Individuals with mTBI showed significantly less EEG global coherence compared to control subjects while awake, but not during sleep. EEG global coherence was significantly correlated with severity of post-concussive symptoms (as assessed by the Neurobehavioral Symptom Inventory scale). Conclusion and implications Taken together, our data from both mouse and human studies suggest that EEG slow wave quantity and the global coherence index of slow waves may represent a sensitive marker for the diagnosis and prognosis of mTBI and post-concussive symptoms. PMID:28018987

EEG slow waves in traumatic brain injury: Convergent findings in mouse and man.

PubMed

Modarres, Mo; Kuzma, Nicholas N; Kretzmer, Tracy; Pack, Allan I; Lim, Miranda M

2016-07-01

Evidence from previous studies suggests that greater sleep pressure, in the form of EEG-based slow waves, accumulates in specific brain regions that are more active during prior waking experience. We sought to quantify the number and coherence of EEG slow waves in subjects with mild traumatic brain injury (mTBI). We developed a method to automatically detect individual slow waves in each EEG channel, and validated this method using simulated EEG data. We then used this method to quantify EEG-based slow waves during sleep and wake states in both mouse and human subjects with mTBI. A modified coherence index that accounts for information from multiple channels was calculated as a measure of slow wave synchrony. Brain-injured mice showed significantly higher theta:alpha amplitude ratios and significantly more slow waves during spontaneous wakefulness and during prolonged sleep deprivation, compared to sham-injured control mice. Human subjects with mTBI showed significantly higher theta:beta amplitude ratios and significantly more EEG slow waves while awake compared to age-matched control subjects. We then quantified the global coherence index of slow waves across several EEG channels in human subjects. Individuals with mTBI showed significantly less EEG global coherence compared to control subjects while awake, but not during sleep. EEG global coherence was significantly correlated with severity of post-concussive symptoms (as assessed by the Neurobehavioral Symptom Inventory scale). Taken together, our data from both mouse and human studies suggest that EEG slow wave quantity and the global coherence index of slow waves may represent a sensitive marker for the diagnosis and prognosis of mTBI and post-concussive symptoms.

Global Education as a Way of Reinforcing the Process by Which a Solidaritous and Just World is Built

NASA Astrophysics Data System (ADS)

Kaniewska, Małgorzata; Klimski, Marcin

2017-12-01

Global education is a part of civic education and upbringing that contributes to their scope through the better understanding of various phenomena and global interdependencies that it affords. It thus represents a response to globalisation processes that has as its goal the development of critical thinking skills in schoolchildren from an early age, with a view to stereotypes and prejudices being combated, human life and human dignity being shown values, and emphasis placed on equality, peace, tolerance, solidarity and equity. The paper considers the reasons for including axiological reflection in school education programmes encompassing matters that are global in nature. Also presented are methods by which to achieve postulates of global education at the primary-school teaching level, as well as the results of research into the level of knowledge on key aspects of this education that are present among primary-school teachers.

Comparative sensitivity and inhibitor tolerance of GlobalFiler® PCR Amplification and Investigator® 24plex QS kits for challenging samples.

PubMed

Elwick, Kyleen; Mayes, Carrie; Hughes-Stamm, Sheree

2018-05-01

In cases such as mass disasters or missing persons, human remains are challenging to identify as they may be fragmented, burnt, been buried, decomposed, and/or contain inhibitory substances. This study compares the performance of a relatively new STR kit in the US market (Investigator® 24plex QS kit; Qiagen) with the GlobalFiler® PCR Amplification kit (Thermo Fisher Scientific) when genotyping highly inhibited and low level DNA samples. In this study, DNA samples ranging from 1 ng to 7.8 pg were amplified to define the sensitivity of two systems. In addition, DNA (1 ng and 0.1 ng input amounts) was spiked with various concentrations of five inhibitors common to human remains (humic acid, melanin, hematin, collagen, calcium). Furthermore, bone (N = 5) and tissue samples from decomposed human remains (N = 6) were used as mock casework samples for comparative analysis with both STR kits. The data suggest that the GlobalFiler® kit may be slightly more sensitive than the Investigator® kit. On average STR profiles appeared to be more balanced and average peak heights were higher when using the GlobalFiler® kit. However, the data also show that the Investigator® kit may be more tolerant to common PCR inhibitors. While both STR kits showed a decrease in alleles as the inhibitor concentration increased, more complete profiles were obtained when the Investigator® kit was used. Of the 11 bone and decomposed tissue samples tested, 8 resulted in more complete and balanced STR profiles when amplified with the GlobalFiler® kit. Copyright © 2018 Elsevier B.V. All rights reserved.

Using Performance Tools to Support Experiments in HPC Resilience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naughton, III, Thomas J; Boehm, Swen; Engelmann, Christian

2014-01-01

The high performance computing (HPC) community is working to address fault tolerance and resilience concerns for current and future large scale computing platforms. This is driving enhancements in the programming environ- ments, specifically research on enhancing message passing libraries to support fault tolerant computing capabilities. The community has also recognized that tools for resilience experimentation are greatly lacking. However, we argue that there are several parallels between performance tools and resilience tools . As such, we believe the rich set of HPC performance-focused tools can be extended (repurposed) to benefit the resilience community. In this paper, we describe the initialmore » motivation to leverage standard HPC per- formance analysis techniques to aid in developing diagnostic tools to assist fault tolerance experiments for HPC applications. These diagnosis procedures help to provide context for the system when the errors (failures) occurred. We describe our initial work in leveraging an MPI performance trace tool to assist in provid- ing global context during fault injection experiments. Such tools will assist the HPC resilience community as they extend existing and new application codes to support fault tolerances.« less

Maximal oxygen consumption increases with temperature in the European eel (Anguilla anguilla) through increased heart rate and arteriovenous extraction.

PubMed

Claësson, Débora; Wang, Tobias; Malte, Hans

2016-01-01

Global warming results in increasing water temperature, which may represent a threat to aquatic ectotherms. The rising temperature affects ecology through physiology, by exerting a direct limiting effect on the individual. The mechanism controlling individual thermal tolerance is still elusive, but some evidence shows that the heart plays a central role, and that insufficient transport of oxygen to the respiring tissues may determine the thermal tolerance of animals. In this study, the influence of the heart in thermal limitation was investigated by measurements of aerobic scope in the European eel ( Anguilla anguilla ) together with measurements of cardiac output during rest and activity. Aerobic capacity was not limited by an acutely increased temperature in the European eel. Oxygen demand was met by an increase in heart rate and arteriovenous extraction. These findings suggest that thermal tolerance during exposure to acute temperature changes is not defined by oxygen transport capacity in the eel, and other mechanisms may play a central role in limiting thermal tolerance in these fish.

Increase in ethanol yield via elimination of lactate production in an ethanol-tolerant mutant of Clostridium thermocellum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biswas, Ranjita; Prabhu, Sandeep; Lynd, Lee R

2014-01-01

Large-scale production of lignocellulosic biofuel is a potential solution to sustainably meet global energy needs. One-step consolidated bioprocessing (CBP) is a potentially advantageous approach for the production of biofuels, but requires an organism capable of hydrolyzing biomass to sugars and fermenting the sugars to ethanol at commercially viable titers and yields. Clostridium thermocellum, a thermophilic anaerobe, can ferment cellulosic biomass to ethanol and organic acids, but low yield, low titer, and ethanol sensitivity remain barriers to industrial production. Here, we deleted the hypoxanthine phosphoribosyltransferase gene in ethanol tolerant strain of C. thermocellum adhE*(EA) in order to allow use of previouslymore » developed gene deletion tools, then deleted lactate dehydrogenase (ldh) to redirect carbon flux towards ethanol. Upon deletion of ldh, the adhE*(EA) ldh strain produced 30% more ethanol than wild type on minimal medium. The adhE*(EA) ldh strain retained tolerance to 5% v/v ethanol, resulting in an ethanol tolerant platform strain of C. thermocellum for future metabolic engineering efforts.« less

Toward an integrated monitoring framework to assess the effects of tropical forest degradation and recovery on carbon stocks and biodiversity

Treesearch

Mercedes M. C. Bustamante; Iris Roitman; T. Mitchell Aide; Ane Alencar; Liana O. Anderson; Luiz Aragao; Gregory P. Asner; Jos Barlow; Erika Berenguer; Jeffrey Chambers; Marcos H. Costa; Thierry Fanin; Laerte G. Ferreira; Joice Ferreira; Michael Keller; William E. Magnusson; Lucia Morales-Barquero; Douglas Morton; Jean P. H. B. Ometto; Michael Palace; Carlos A. Peres; Divino Silverio; Susan Trumbore; Ima C. G. Vieira

2015-01-01

Tropical forests harbor a significant portion of global biodiversity and are a critical component of the climate system. Reducing deforestation and forest degradation contributes to global climate-change mitigation efforts, yet emissions and removals from forest dynamics are still poorly quantified. We reviewed the main challenges to estimate changes in carbon stocks...

Global malaria connectivity through air travel.

PubMed

Huang, Zhuojie; Tatem, Andrew J

2013-08-02

Air travel has expanded at an unprecedented rate and continues to do so. Its effects have been seen on malaria in rates of imported cases, local outbreaks in non-endemic areas and the global spread of drug resistance. With elimination and global eradication back on the agenda, changing levels and compositions of imported malaria in malaria-free countries, and the threat of artemisinin resistance spreading from Southeast Asia, there is a need to better understand how the modern flow of air passengers connects each Plasmodium falciparum- and Plasmodium vivax-endemic region to the rest of the world. Recently constructed global P. falciparum and P.vivax malaria risk maps, along with data on flight schedules and modelled passenger flows across the air network, were combined to describe and quantify global malaria connectivity through air travel. Network analysis approaches were then utilized to describe and quantify the patterns that exist in passenger flows weighted by malaria prevalence. Finally, the connectivity within and to the Southeast Asia region where the threat of imported artemisinin resistance arising is highest, was examined to highlight risk routes for its spread. The analyses demonstrate the substantial connectivity that now exists between and from malaria-endemic regions through air travel. While the air network provides connections to previously isolated malarious regions, it is clear that great variations exist, with significant regional communities of airports connected by higher rates of flow standing out. The structures of these communities are often not geographically coherent, with historical, economic and cultural ties evident, and variations between P. falciparum and P. vivax clear. Moreover, results highlight how well connected the malaria-endemic areas of Africa are now to Southeast Asia, illustrating the many possible routes that artemisinin-resistant strains could take. The continuing growth in air travel is playing an important role in the global epidemiology of malaria, with the endemic world becoming increasingly connected to both malaria-free areas and other endemic regions. The research presented here provides an initial effort to quantify and analyse the connectivity that exists across the malaria-endemic world through air travel, and provide a basic assessment of the risks it results in for movement of infections.

Global malaria connectivity through air travel

PubMed Central

2013-01-01

Background Air travel has expanded at an unprecedented rate and continues to do so. Its effects have been seen on malaria in rates of imported cases, local outbreaks in non-endemic areas and the global spread of drug resistance. With elimination and global eradication back on the agenda, changing levels and compositions of imported malaria in malaria-free countries, and the threat of artemisinin resistance spreading from Southeast Asia, there is a need to better understand how the modern flow of air passengers connects each Plasmodium falciparum- and Plasmodium vivax-endemic region to the rest of the world. Methods Recently constructed global P. falciparum and P.vivax malaria risk maps, along with data on flight schedules and modelled passenger flows across the air network, were combined to describe and quantify global malaria connectivity through air travel. Network analysis approaches were then utilized to describe and quantify the patterns that exist in passenger flows weighted by malaria prevalence. Finally, the connectivity within and to the Southeast Asia region where the threat of imported artemisinin resistance arising is highest, was examined to highlight risk routes for its spread. Results The analyses demonstrate the substantial connectivity that now exists between and from malaria-endemic regions through air travel. While the air network provides connections to previously isolated malarious regions, it is clear that great variations exist, with significant regional communities of airports connected by higher rates of flow standing out. The structures of these communities are often not geographically coherent, with historical, economic and cultural ties evident, and variations between P. falciparum and P. vivax clear. Moreover, results highlight how well connected the malaria-endemic areas of Africa are now to Southeast Asia, illustrating the many possible routes that artemisinin-resistant strains could take. Discussion The continuing growth in air travel is playing an important role in the global epidemiology of malaria, with the endemic world becoming increasingly connected to both malaria-free areas and other endemic regions. The research presented here provides an initial effort to quantify and analyse the connectivity that exists across the malaria-endemic world through air travel, and provide a basic assessment of the risks it results in for movement of infections. PMID:23914776

Basal tolerance to heat and cold exposure of the spotted wing drosophila, Drosophila suzukii

PubMed Central

Enriquez, Thomas

2017-01-01

The spotted wing Drosophila, Drosophila suzukii, is a new pest in Europe and America which causes severe damages, mostly to stone fruit crops. Temperature and humidity are among the most important abiotic factors governing insect development and fitness. In many situations, temperature can become stressful thus compromising survival. The ability to cope with thermal stress depends on basal level of thermal tolerance. Basic knowledge on temperature-dependent mortality of D. suzukii is essential to facilitate management of this pest. The objective of the present study was to investigate D. suzukii basal cold and heat tolerance. Adults and pupae were subjected to six low temperatures (−5–7.5 °C) and seven high temperatures (30–37 °C) for various durations, and survival-time-temperature relationships were investigated. Data showed that males were globally more cold tolerant than females. At temperature above 5 °C, adult cold mortality became minor even after prolonged exposures (e.g., only 20% mortality after one month at 7.5 °C). Heat tolerance of males was lower than that of females at the highest tested temperatures (34, 35 and 37 °C). Pupae appeared much less cold tolerant than adults at all temperatures (e.g., Lt50 at 5° C: 4–5 d for adults vs. 21 h for pupae). Pupae were more heat tolerant than adults at the most extreme high temperatures (e.g., Lt50 at 37 °C: 30 min for adults vs. 4 h for pupae). The pupal thermal tolerance was further investigated under low vs. high humidity. Low relative humidity did not affect pupal cold survival, but it reduced survival under heat stress. Overall, this study shows that survival of D. suzukii under heat and cold conditions can vary with stress intensity, duration, humidity, sex and stage, and the methodological approach used here, which was based on thermal tolerance landscapes, provides a comprehensive description of D. suzukiithermal tolerance and limits. PMID:28348931

Genome-wide association mapping of canopy wilting in diverse soybean genotypes

USDA-ARS?s Scientific Manuscript database

Drought stress is a major global constraint for crop production, and slow canopy wilting has been shown to be a promising trait for improving drought tolerance. The objective of this study was to identify genetic loci associated with canopy wilting and confirm those loci with previously reported can...

Culturally-Based and Culturally-Biased Aspects of Knowing the Other

ERIC Educational Resources Information Center

Makarova, Elena A.; Makarova, Elena L.

2014-01-01

Interaction of cultures calls for cultural awareness development. Knowledge is a powerful weapon to overcome prejudices, stereotyping and xenophobia. To build cultural awareness and tolerance to the peculiarities of someone else's culture, global learners must learn how to determine the existence of differences between cultures and how to adapt…

The resurrection genome of Boea hygrometrica: A blueprint for survival of dehydration

USDA-ARS?s Scientific Manuscript database

The dicot, Boea hygrometrica, is an important plant model for the discovery of genes central to desiccation tolerance in plants; an essential trait in land plant evolution and the foundation for global agriculture. We used a vegetative clonal line to uncover the sequence and characterize the respons...

Evaluation of Breakthrough's "America 2049" Game

ERIC Educational Resources Information Center

Diamond, James; Brunner, Cornelia

2011-01-01

Breakthrough, a global human rights organization, produced "America 2049," an alternate-reality game set in a dystopian future in which the United States is on the verge of breaking apart because of an inability to tolerate diversity and promote human rights. During the 12-week game launch, players uncovered artifacts related to the…

Multilingual School Population: Ensuring School Belonging by Tolerating Multilingualism

ERIC Educational Resources Information Center

Van Der Wildt, Anouk; Van Avermaet, Piet; Van Houtte, Mieke

2017-01-01

Societies have become super-diverse due to migration and globalization. Many mainstream classroom teachers feel managing the linguistic variety children bring to school is challenging. This often leads to restrictive language policies. Research on multilingualism has given us insight into the multilingual realities of pupils, which allows us to…

METAL CONTENT OF DANDELION (TARAXACUM OFFICINALE) LEAVES IN RELATION TO SOIL CONTAMINATION AND AIRBORNE PARTICULATE MATTER. (R826602)

EPA Science Inventory

The global distribution of the common dandelion (Taraxacum officinale Weber, sensu lato; Asteraceae), along with its ability to tolerate a wide range of environmental conditions, make this `species' a particularly attractive candidate to evaluate for its ...

Investigating crosstalk between heat tolerance and redox status through suppressor screening of EMS mutagenized Arabidopsis monothioglutaredoxin GRXS17 mutants

USDA-ARS?s Scientific Manuscript database

Global environmental temperature changes threaten innumerable plant species. While various signaling networks regulate plant responses to heat stress (HS), the mechanisms unifying these diverse processes are largely unknown. The thioredoxin (Trx) and glutaredoxin (Grx) systems help control cellular ...

Proteome analysis of leaves of the desiccation-tolerant grass, Sporobolus stapfianus, in response to desiccation

USDA-ARS?s Scientific Manuscript database

Drought and its affects on agricultural production is a serious issue facing global efforts to increase food supplies and ensure food security for the growing world population. Understanding how plants respond to dehydration is an important prerequisite for developing strategies for crop improvement...

A Pedagogy for Global Understanding--Intercultural Dialogue: From Theory to Practice

ERIC Educational Resources Information Center

Dulabaum, Nina L.

2011-01-01

Given the current tensions and animosities between people of varying cultural and ethnic groups, intercultural dialogue, rooted in Europe's humanist tradition, offers a concrete strategy for fostering understanding, promoting tolerance and breaking down barriers based on stereotypes and xenophobic violence. As the world's population increases each…

Growth of Atlantic salmon, Salmo salar fed diets containing barley protein concentrate

USDA-ARS?s Scientific Manuscript database

Atlantic salmon (Salmo salar) is an important cultured carnivorous species that in the past has not tolerated high levels of most plant protein feed ingredients in the diet. In order to increase efficiency, sustainability and production to meet global demand, new sources of protein must be incorpo...

Distributed fault-tolerant time-varying formation control for high-order linear multi-agent systems with actuator failures.

PubMed

Hua, Yongzhao; Dong, Xiwang; Li, Qingdong; Ren, Zhang

2017-11-01

This paper investigates the fault-tolerant time-varying formation control problems for high-order linear multi-agent systems in the presence of actuator failures. Firstly, a fully distributed formation control protocol is presented to compensate for the influences of both bias fault and loss of effectiveness fault. Using the adaptive online updating strategies, no global knowledge about the communication topology is required and the bounds of actuator failures can be unknown. Then an algorithm is proposed to determine the control parameters of the fault-tolerant formation protocol, where the time-varying formation feasible conditions and an approach to expand the feasible formation set are given. Furthermore, the stability of the proposed algorithm is proven based on the Lyapunov-like theory. Finally, two simulation examples are given to demonstrate the effectiveness of the theoretical results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Drought-Responsive Mechanisms in Plant Leaves Revealed by Proteomics.

PubMed

Wang, Xiaoli; Cai, Xiaofeng; Xu, Chenxi; Wang, Quanhua; Dai, Shaojun

2016-10-18

Plant drought tolerance is a complex trait that requires a global view to understand its underlying mechanism. The proteomic aspects of plant drought response have been extensively investigated in model plants, crops and wood plants. In this review, we summarize recent proteomic studies on drought response in leaves to reveal the common and specialized drought-responsive mechanisms in different plants. Although drought-responsive proteins exhibit various patterns depending on plant species, genotypes and stress intensity, proteomic analyses show that dominant changes occurred in sensing and signal transduction, reactive oxygen species scavenging, osmotic regulation, gene expression, protein synthesis/turnover, cell structure modulation, as well as carbohydrate and energy metabolism. In combination with physiological and molecular results, proteomic studies in leaves have helped to discover some potential proteins and/or metabolic pathways for drought tolerance. These findings provide new clues for understanding the molecular basis of plant drought tolerance.

Drought-Responsive Mechanisms in Plant Leaves Revealed by Proteomics

PubMed Central

Wang, Xiaoli; Cai, Xiaofeng; Xu, Chenxi; Wang, Quanhua; Dai, Shaojun

2016-01-01

Plant drought tolerance is a complex trait that requires a global view to understand its underlying mechanism. The proteomic aspects of plant drought response have been extensively investigated in model plants, crops and wood plants. In this review, we summarize recent proteomic studies on drought response in leaves to reveal the common and specialized drought-responsive mechanisms in different plants. Although drought-responsive proteins exhibit various patterns depending on plant species, genotypes and stress intensity, proteomic analyses show that dominant changes occurred in sensing and signal transduction, reactive oxygen species scavenging, osmotic regulation, gene expression, protein synthesis/turnover, cell structure modulation, as well as carbohydrate and energy metabolism. In combination with physiological and molecular results, proteomic studies in leaves have helped to discover some potential proteins and/or metabolic pathways for drought tolerance. These findings provide new clues for understanding the molecular basis of plant drought tolerance. PMID:27763546

A comprehensive analysis of the IMRT dose delivery process using statistical process control (SPC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerard, Karine; Grandhaye, Jean-Pierre; Marchesi, Vincent

The aim of this study is to introduce tools to improve the security of each IMRT patient treatment by determining action levels for the dose delivery process. To achieve this, the patient-specific quality control results performed with an ionization chamber--and which characterize the dose delivery process--have been retrospectively analyzed using a method borrowed from industry: Statistical process control (SPC). The latter consisted in fulfilling four principal well-structured steps. The authors first quantified the short term variability of ionization chamber measurements regarding the clinical tolerances used in the cancer center ({+-}4% of deviation between the calculated and measured doses) by calculatingmore » a control process capability (C{sub pc}) index. The C{sub pc} index was found superior to 4, which implies that the observed variability of the dose delivery process is not biased by the short term variability of the measurement. Then, the authors demonstrated using a normality test that the quality control results could be approximated by a normal distribution with two parameters (mean and standard deviation). Finally, the authors used two complementary tools--control charts and performance indices--to thoroughly analyze the IMRT dose delivery process. Control charts aim at monitoring the process over time using statistical control limits to distinguish random (natural) variations from significant changes in the process, whereas performance indices aim at quantifying the ability of the process to produce data that are within the clinical tolerances, at a precise moment. The authors retrospectively showed that the analysis of three selected control charts (individual value, moving-range, and EWMA control charts) allowed efficient drift detection of the dose delivery process for prostate and head-and-neck treatments before the quality controls were outside the clinical tolerances. Therefore, when analyzed in real time, during quality controls, they should improve the security of treatments. They also showed that the dose delivery processes in the cancer center were in control for prostate and head-and-neck treatments. In parallel, long term process performance indices (P{sub p}, P{sub pk}, and P{sub pm}) have been analyzed. Their analysis helped defining which actions should be undertaken in order to improve the performance of the process. The prostate dose delivery process has been shown statistically capable (0.08% of the results is expected to be outside the clinical tolerances) contrary to the head-and-neck dose delivery process (5.76% of the results are expected to be outside the clinical tolerances).« less

A comprehensive analysis of the IMRT dose delivery process using statistical process control (SPC).

PubMed

Gérard, Karine; Grandhaye, Jean-Pierre; Marchesi, Vincent; Kafrouni, Hanna; Husson, François; Aletti, Pierre

2009-04-01

The aim of this study is to introduce tools to improve the security of each IMRT patient treatment by determining action levels for the dose delivery process. To achieve this, the patient-specific quality control results performed with an ionization chamber--and which characterize the dose delivery process--have been retrospectively analyzed using a method borrowed from industry: Statistical process control (SPC). The latter consisted in fulfilling four principal well-structured steps. The authors first quantified the short-term variability of ionization chamber measurements regarding the clinical tolerances used in the cancer center (+/- 4% of deviation between the calculated and measured doses) by calculating a control process capability (C(pc)) index. The C(pc) index was found superior to 4, which implies that the observed variability of the dose delivery process is not biased by the short-term variability of the measurement. Then, the authors demonstrated using a normality test that the quality control results could be approximated by a normal distribution with two parameters (mean and standard deviation). Finally, the authors used two complementary tools--control charts and performance indices--to thoroughly analyze the IMRT dose delivery process. Control charts aim at monitoring the process over time using statistical control limits to distinguish random (natural) variations from significant changes in the process, whereas performance indices aim at quantifying the ability of the process to produce data that are within the clinical tolerances, at a precise moment. The authors retrospectively showed that the analysis of three selected control charts (individual value, moving-range, and EWMA control charts) allowed efficient drift detection of the dose delivery process for prostate and head-and-neck treatments before the quality controls were outside the clinical tolerances. Therefore, when analyzed in real time, during quality controls, they should improve the security of treatments. They also showed that the dose delivery processes in the cancer center were in control for prostate and head-and-neck treatments. In parallel, long-term process performance indices (P(p), P(pk), and P(pm)) have been analyzed. Their analysis helped defining which actions should be undertaken in order to improve the performance of the process. The prostate dose delivery process has been shown statistically capable (0.08% of the results is expected to be outside the clinical tolerances) contrary to the head-and-neck dose delivery process (5.76% of the results are expected to be outside the clinical tolerances).

Comparative genomic and proteomic analyses of Clostridium acetobutylicum Rh8 and its parent strain DSM 1731 revealed new understandings on butanol tolerance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bao, Guanhui; University of Chinese Academy of Sciences, Beijing; Dong, Hongjun

Highlights: • Genomes of a butanol tolerant strain and its parent strain were deciphered. • Comparative genomic and proteomic was applied to understand butanol tolerance. • None differentially expressed proteins have mutations in its corresponding genes. • Mutations in ribosome might be responsible for the global difference of proteomics. - Abstract: Clostridium acetobutylicum strain Rh8 is a butanol-tolerant mutant which can tolerate up to 19 g/L butanol, 46% higher than that of its parent strain DSM 1731. We previously performed comparative cytoplasm- and membrane-proteomic analyses to understand the mechanism underlying the improved butanol tolerance of strain Rh8. In this work,more » we further extended this comparison to the genomic level. Compared with the genome of the parent strain DSM 1731, two insertion sites, four deletion sites, and 67 single nucleotide variations (SNVs) are distributed throughout the genome of strain Rh8. Among the 67 SNVs, 16 SNVs are located in the predicted promoters and intergenic regions; while 29 SNVs are located in the coding sequence, affecting a total of 21 proteins involved in transport, cell structure, DNA replication, and protein translation. The remaining 22 SNVs are located in the ribosomal genes, affecting a total of 12 rRNA genes in different operons. Analysis of previous comparative proteomic data indicated that none of the differentially expressed proteins have mutations in its corresponding genes. Rchange Algorithms analysis indicated that the mutations occurred in the ribosomal genes might change the ribosome RNA thermodynamic characteristics, thus affect the translation strength of these proteins. Take together, the improved butanol tolerance of C. acetobutylicum strain Rh8 might be acquired through regulating the translational process to achieve different expression strength of genes involved in butanol tolerance.« less

Is sexual reproduction of high-mountain plants endangered by heat?

PubMed

Ladinig, Ursula; Pramsohler, Manuel; Bauer, Ines; Zimmermann, Sonja; Neuner, Gilbert; Wagner, Johanna

2015-04-01

Strong solar irradiation in combination with still air and dry soil can cause prostrate high-mountain plants to heat up considerably and ultimately suffer heat damage. Such heat damage has been repeatedly shown for vegetative structures, but not for reproductive structures, which we expected to be particularly vulnerable to heat. Heat effects on cold-adapted plants may increase with rising global temperatures and the predicted increase in heat waves. We have tested the heat tolerance of reproductive versus vegetative shoots at different reproductive stages, comparing ten common plant species from different elevation belts in the European Alps. Plant samples were exposed to temperatures in 2-K steps of 30 min each between 42 and 56 °C. Heat damage was assessed by visual rating and vital staining. Reproductive shoots were on average 2.5 K less heat tolerant (LT50, i.e. the mean temperature causing 50 % heat damage, 47.2 °C) than vegetative shoots (mean LT50 49.7 °C). Initial heat injuries (mean LT10) were observed at 43-45 °C in heat-susceptible species and at 45-47 °C in more heat-tolerant species, in at least one reproductive stage. Generally, heat tolerance was significantly higher during fruiting than during the bud stages and anthesis. Prostrate species with acaulescent buds and flowers tolerated heat better than those with caulescent buds and flowers. Petals were the most heat-susceptible plant structure and mature pollen the most heat tolerant. Based on these data, heat tolerance of reproductive structures appears to be adapted to the prevailing maximum temperatures which the plants experience during different reproductive stages in their environment. During hot spells, however, heat tolerance thresholds may be exceeded. More frequent heat waves would decrease the reproductive output and, consequently, the competitiveness of heat-susceptible species.

Global optimization of multimode interference structure for ratiometric wavelength measurement

NASA Astrophysics Data System (ADS)

Wang, Qian; Farrell, Gerald; Hatta, Agus Muhamad

2007-07-01

The multimode interference structure is conventionally used as a splitter/combiner. In this paper, it is optimised as an edge filter for ratiometric wavelength measurement, which can be used in demodulation of fiber Bragg grating sensing. The global optimization algorithm-adaptive simulated annealing is introduced in the design of multimode interference structure including the length and width of the multimode waveguide section, and positions of the input and output waveguides. The designed structure shows a suitable spectral response for wavelength measurement and a good fabrication tolerance.

Impacts of Groundwater Pumping on Regional and Global Water Resources

NASA Technical Reports Server (NTRS)

Wada, Yoshihide

2016-01-01

Except frozen water in ice and glaciers (68%), groundwater is the world's largest distributed store of freshwater (30%), and has strategic importance to global food and water security. In this chapter, the most recent advances assessing human impact on regional and global groundwater resources are reviewed. This chapter critically evaluates the recently advanced modeling approaches quantifying the effect of groundwater pumping in regional and global groundwater resources and the evidence of feedback to the Earth system including sea-level rise associated with groundwater use. At last, critical challenges and opportunities are identified in the use of groundwater to adapt to growing food demand and uncertain climate.

Meta-Analysis of the Effect of Overexpression of Dehydration-Responsive Element Binding Family Genes on Temperature Stress Tolerance and Related Responses

PubMed Central

Dong, Chao; Ma, Yuanchun; Zheng, Dan; Wisniewski, Michael; Cheng, Zong-Ming

2018-01-01

Dehydration-responsive element binding proteins are transcription factors that play a critical role in plant response to temperature stress. Over-expression of DREB genes has been demonstrated to enhance temperature stress tolerance. A series of physiological and biochemical modifications occur in a complex and integrated way when plants respond to temperature stress, which makes it difficult to assess the mechanism underlying the DREB enhancement of stress tolerance. A meta-analysis was conducted of the effect of DREB overexpression on temperature stress tolerance and the various parameters modulated by overexpression that were statistically quantified in 75 published articles. The meta-analysis was conducted to identify the overall influence of DREB on stress-related parameters in transgenic plants, and to determine how different experimental variables affect the impact of DREB overexpression. Viewed across all the examined studies, 7 of the 8 measured plant parameters were significantly (p ≤ 0.05) modulated in DREB-transgenic plants when they were subjected to temperature stress, while 2 of the 8 parameters were significantly affected in non-stressed control plants. The measured parameters were modulated by 32% or more by various experimental variables. The modulating variables included, acclimated or non-acclimated, type of promoter, stress time and severity, source of the donor gene, and whether the donor and recipient were the same genus. These variables all had a significant effect on the observed impact of DREB overexpression. Further studies should be conducted under field conditions to better understand the role of DREB transcription factors in enhancing plant tolerance to temperature stress. PMID:29896212

Differentially delayed root proteome responses to salt stress in sugar cane varieties.

PubMed

Pacheco, Cinthya Mirella; Pestana-Calsa, Maria Clara; Gozzo, Fabio Cesar; Mansur Custodio Nogueira, Rejane Jurema; Menossi, Marcelo; Calsa, Tercilio

2013-12-06

Soil salinity is a limiting factor to sugar cane crop development, although in general plants present variable mechanisms of tolerance to salinity stress. The molecular basis underlying these mechanisms can be inferred by using proteomic analysis. Thus, the objective of this work was to identify differentially expressed proteins in sugar cane plants submitted to salinity stress. For that, a greenhouse experiment was established with four sugar cane varieties and two salt conditions, 0 mM (control) and 200 mM NaCl. Physiological and proteomics analyses were performed after 2 and 72 h of stress induction by salt. Distinct physiological responses to salinity stress were observed in the varieties and linked to tolerance mechanisms. In proteomic analysis, the roots soluble protein fraction was extracted, quantified, and analyzed through bidimensional electrophoresis. Gel images analyses were done computationally, where in each contrast only one variable was considered (salinity condition or variety). Differential spots were excised, digested by trypsin, and identified via mass spectrometry. The tolerant variety RB867515 showed the highest accumulation of proteins involved in growth, development, carbohydrate and energy metabolism, reactive oxygen species metabolization, protein protection, and membrane stabilization after 2 h of stress. On the other hand, the presence of these proteins in the sensitive variety was verified only in stress treatment after 72 h. These data indicate that these stress responses pathways play a role in the tolerance to salinity in sugar cane, and their effectiveness for phenotypical tolerance depends on early stress detection and activation of the coding genes expression.

Impact of exercise on diurnal and nocturnal markers of glycaemic variability and oxidative stress in obese individuals with type 2 diabetes or impaired glucose tolerance.

PubMed

Farabi, Sarah S; Carley, David W; Smith, Donald; Quinn, Lauretta

2015-09-01

We measured the effects of a single bout of exercise on diurnal and nocturnal oxidative stress and glycaemic variability in obese subjects with type 2 diabetes mellitus or impaired glucose tolerance versus obese healthy controls. Subjects (in random order) performed either a single 30-min bout of moderate-intensity exercise or remained sedentary for 30 min at two separate visits. To quantify glycaemic variability, standard deviation of glucose (measured by continuous glucose monitoring system) and continuous overlapping net glycaemic action of 1-h intervals (CONGA-1) were calculated for three 12-h intervals during each visit. Oxidative stress was measured by 15-isoprostane F(2t) levels in urine collections for matching 12-h intervals. Exercise reduced daytime glycaemic variability (ΔCONGA-1 = -12.62 ± 5.31 mg/dL, p = 0.04) and urinary isoprostanes (ΔCONGA-1 = -0.26 ± 0.12 ng/mg, p = 0.04) in the type 2 diabetes mellitus/impaired glucose tolerance group. Daytime exercise-induced change in urinary 15-isoprostane F(2t) was significantly correlated with both daytime standard deviation (r = 0.68, p = 0.03) and with subsequent overnight standard deviation (r = 0.73, p = 0.027) in the type 2 diabetes mellitus/impaired glucose tolerance group. Exercise significantly impacts the relationship between diurnal oxidative stress and nocturnal glycaemic variability in individuals with type 2 diabetes mellitus/impaired glucose tolerance. © The Author(s) 2015.

Identification of novel drought-tolerant-associated SNPs in common bean (Phaseolus vulgaris)

PubMed Central

Villordo-Pineda, Emiliano; González-Chavira, Mario M.; Giraldo-Carbajo, Patricia; Acosta-Gallegos, Jorge A.; Caballero-Pérez, Juan

2015-01-01

Common bean (Phaseolus vulgaris L.) is a leguminous in high demand for human nutrition and a very important agricultural product. Production of common bean is constrained by environmental stresses such as drought. Although conventional plant selection has been used to increase production yield and stress tolerance, drought tolerance selection based on phenotype is complicated by associated physiological, anatomical, cellular, biochemical, and molecular changes. These changes are modulated by differential gene expression. A common method to identify genes associated with phenotypes of interest is the characterization of Single Nucleotide Polymorphims (SNPs) to link them to specific functions. In this work, we selected two drought-tolerant parental lines from Mesoamerica, Pinto Villa, and Pinto Saltillo. The parental lines were used to generate a population of 282 families (F3:5) and characterized by 169 SNPs. We associated the segregation of the molecular markers in our population with phenotypes including flowering time, physiological maturity, reproductive period, plant, seed and total biomass, reuse index, seed yield, weight of 100 seeds, and harvest index in three cultivation cycles. We observed 83 SNPs with significant association (p < 0.0003 after Bonferroni correction) with our quantified phenotypes. Phenotypes most associated were days to flowering and seed biomass with 58 and 44 associated SNPs, respectively. Thirty-seven out of the 83 SNPs were annotated to a gene with a potential function related to drought tolerance or relevant molecular/biochemical functions. Some SNPs such as SNP28 and SNP128 are related to starch biosynthesis, a common osmotic protector; and SNP18 is related to proline biosynthesis, another well-known osmotic protector. PMID:26257755

Identification of novel drought-tolerant-associated SNPs in common bean (Phaseolus vulgaris).

PubMed

Villordo-Pineda, Emiliano; González-Chavira, Mario M; Giraldo-Carbajo, Patricia; Acosta-Gallegos, Jorge A; Caballero-Pérez, Juan

2015-01-01

Common bean (Phaseolus vulgaris L.) is a leguminous in high demand for human nutrition and a very important agricultural product. Production of common bean is constrained by environmental stresses such as drought. Although conventional plant selection has been used to increase production yield and stress tolerance, drought tolerance selection based on phenotype is complicated by associated physiological, anatomical, cellular, biochemical, and molecular changes. These changes are modulated by differential gene expression. A common method to identify genes associated with phenotypes of interest is the characterization of Single Nucleotide Polymorphims (SNPs) to link them to specific functions. In this work, we selected two drought-tolerant parental lines from Mesoamerica, Pinto Villa, and Pinto Saltillo. The parental lines were used to generate a population of 282 families (F3:5) and characterized by 169 SNPs. We associated the segregation of the molecular markers in our population with phenotypes including flowering time, physiological maturity, reproductive period, plant, seed and total biomass, reuse index, seed yield, weight of 100 seeds, and harvest index in three cultivation cycles. We observed 83 SNPs with significant association (p < 0.0003 after Bonferroni correction) with our quantified phenotypes. Phenotypes most associated were days to flowering and seed biomass with 58 and 44 associated SNPs, respectively. Thirty-seven out of the 83 SNPs were annotated to a gene with a potential function related to drought tolerance or relevant molecular/biochemical functions. Some SNPs such as SNP28 and SNP128 are related to starch biosynthesis, a common osmotic protector; and SNP18 is related to proline biosynthesis, another well-known osmotic protector.

A real-time Global Warming Index.

PubMed

Haustein, K; Allen, M R; Forster, P M; Otto, F E L; Mitchell, D M; Matthews, H D; Frame, D J

2017-11-13

We propose a simple real-time index of global human-induced warming and assess its robustness to uncertainties in climate forcing and short-term climate fluctuations. This index provides improved scientific context for temperature stabilisation targets and has the potential to decrease the volatility of climate policy. We quantify uncertainties arising from temperature observations, climate radiative forcings, internal variability and the model response. Our index and the associated rate of human-induced warming is compatible with a range of other more sophisticated methods to estimate the human contribution to observed global temperature change.

Human Land-Use Practices Lead to Global Long-Term Increases in Photosynthetic Capacity

NASA Technical Reports Server (NTRS)

Mueller, Thomas; Tucker, Compton J.; Dressler, Gunnar; Pinzon, Jorge E.; Leimgruber, Peter; Dubayah, Ralph O.; Hurtt, George C.; Boehning-Gaese, Katrin; Fagan, William F.

2014-01-01

Long-term trends in photosynthetic capacity measured with the satellite-derived Normalized Difference Vegetation Index (NDVI) are usually associated with climate change. Human impacts on the global land surface are typically not accounted for. Here, we provide the first global analysis quantifying the effect of the earth's human footprint on NDVI trends. Globally, more than 20% of the variability in NDVI trends was explained by anthropogenic factors such as land use, nitrogen fertilization, and irrigation. Intensely used land classes, such as villages, showed the greatest rates of increase in NDVI, more than twice than those of forests. These findings reveal that factors beyond climate influence global long-term trends in NDVI and suggest that global climate change models and analyses of primary productivity should incorporate land use effects.

Global charcoal mobilization from soils via dissolution and riverine transport to the oceans.

PubMed

Jaffé, Rudolf; Ding, Yan; Niggemann, Jutta; Vähätalo, Anssi V; Stubbins, Aron; Spencer, Robert G M; Campbell, John; Dittmar, Thorsten

2013-04-19

Global biomass burning generates 40 million to 250 million tons of charcoal every year, part of which is preserved for millennia in soils and sediments. We have quantified dissolution products of charcoal in a wide range of rivers worldwide and show that globally, a major portion of the annual charcoal production is lost from soils via dissolution and subsequent transport to the ocean. The global flux of soluble charcoal accounts to 26.5 ± 1.8 million tons per year, which is ~10% of the global riverine flux of dissolved organic carbon (DOC). We suggest that the mobilization of charcoal and DOC out of soils is mechanistically coupled. This study closes a major gap in the global charcoal budget and provides critical information in the context of geoengineering.

Measuring the impact of final demand on global production system based on Markov process

NASA Astrophysics Data System (ADS)

Xing, Lizhi; Guan, Jun; Wu, Shan

2018-07-01

Input-output table is a comprehensive and detailed in describing the national economic systems, consisting of supply and demand information among various industrial sectors. The complex network, a theory and method for measuring the structure of complex system, can depict the structural properties of social and economic systems, and reveal the complicated relationships between the inner hierarchies and the external macroeconomic functions. This paper tried to measure the globalization degree of industrial sectors on the global value chain. Firstly, it constructed inter-country input-output network models to reproduce the topological structure of global economic system. Secondly, it regarded the propagation of intermediate goods on the global value chain as Markov process and introduced counting first passage betweenness to quantify the added processing amount when globally final demand stimulates this production system. Thirdly, it analyzed the features of globalization at both global and country-sector level

Transcription Factors and Plants Response to Drought Stress: Current Understanding and Future Directions

PubMed Central

Joshi, Rohit; Wani, Shabir H.; Singh, Balwant; Bohra, Abhishek; Dar, Zahoor A.; Lone, Ajaz A.; Pareek, Ashwani; Singla-Pareek, Sneh L.

2016-01-01

Increasing vulnerability of plants to a variety of stresses such as drought, salt and extreme temperatures poses a global threat to sustained growth and productivity of major crops. Of these stresses, drought represents a considerable threat to plant growth and development. In view of this, developing staple food cultivars with improved drought tolerance emerges as the most sustainable solution toward improving crop productivity in a scenario of climate change. In parallel, unraveling the genetic architecture and the targeted identification of molecular networks using modern “OMICS” analyses, that can underpin drought tolerance mechanisms, is urgently required. Importantly, integrated studies intending to elucidate complex mechanisms can bridge the gap existing in our current knowledge about drought stress tolerance in plants. It is now well established that drought tolerance is regulated by several genes, including transcription factors (TFs) that enable plants to withstand unfavorable conditions, and these remain potential genomic candidates for their wide application in crop breeding. These TFs represent the key molecular switches orchestrating the regulation of plant developmental processes in response to a variety of stresses. The current review aims to offer a deeper understanding of TFs engaged in regulating plant’s response under drought stress and to devise potential strategies to improve plant tolerance against drought. PMID:27471513

Widespread range expansions shape latitudinal variation in insect thermal limits

NASA Astrophysics Data System (ADS)

Lancaster, Lesley T.

2016-06-01

Current anthropogenic impacts, including habitat modification and climate change, may contribute to a sixth mass extinction. To mitigate these impacts and slow further losses of biodiversity, we need to understand which species are most at risk and identify the factors contributing to current and future declines. Such information is often obtained through large-scale, comparative and biogeographic analysis of lineages or traits that are potentially sensitive to ongoing anthropogenic change--for instance to predict which regions are most susceptible to climate change-induced biodiversity loss. However, for this approach to be generally successful, the underlying causes of identified geographical trends need to be carefully considered. Here, I augment and reanalyse a global data set of insect thermal tolerances, evaluating the contribution of recent and contemporary range expansions to latitudinal variation in thermal niche breadth. Previous indications that high-latitude ectotherms exhibit broad thermal niches and high warming tolerances held only for species undergoing range expansions or invasions. In contrast, species with stable or declining geographic ranges exhibit latitudinally decreasing absolute thermal tolerances and no latitudinal variation in tolerance breadths. Thus, non-range-expanding species, particularly insular or endemic species, which are often of highest conservation priority, are unlikely to tolerate future climatic warming at high latitudes.

Effects of elevated temperature on coral reef fishes: loss of hypoxia tolerance and inability to acclimate.

PubMed

Nilsson, Göran E; Ostlund-Nilsson, Sara; Munday, Philip L

2010-08-01

Water temperature is expected to rise on coral reefs due to global warming. Here, we have examined if increased temperature reduces the hypoxia tolerance of coral reef fish (measured as critical [O(2)]), and if temperature acclimation in adults can change the resting rate of O(2) consumption and critical [O(2)]. Two common species from Lizard Island (Great Barrier Reef, Australia) were tested, Doederlein's cardinalfish (Ostorhinchus doederleini) and lemon damselfish (Pomacentrus moluccensis). In both species, a 3 degrees C rise in water temperature caused increased oxygen consumption and reduced hypoxia tolerance, changes that were not reduced by acclimation to the higher temperature for 7 to 22 days. Critical [O(2)] increased by 71% in the cardinalfish and by 23% in the damselfish at 32 degrees C compared to 29 degrees C. The higher oxygen needs are likely to reduce the aerobic scope, which could negatively affect the capacity for feeding, growth and reproduction. The reduced hypoxia tolerance may force the fishes out of their nocturnal shelters in the coral matrix, exposing them to predation. The consequences for population and species survival could be severe unless developmental phenotypic plasticity within generations or genetic adaptation between generations could produce individuals that are more tolerant to a warmer future. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Salinity tolerance and mycorrhizal responsiveness of native xeroriparian plants in semi-arid western USA

USGS Publications Warehouse

Beauchamp, Vanessa B.; Walz, C.; Shafroth, P.B.

2009-01-01

Restoration of salt-affected soils is a global concern. In the western United States, restoration of salinized land, particularly in river valleys, often involves control of Tamarix, an introduced species with high salinity tolerance. Revegetation of hydrologically disconnected floodplains and terraces after Tamarix removal is often difficult because of limited knowledge regarding the salinity tolerance of candidate native species for revegetation. Additionally, Tamarix appears to be non-mycorrhizal. Extended occupation of Tamarix may deplete arbuscular mycorrhizal fungi in the soil, further decreasing the success of revegetation efforts. To address these issues, we screened 42 species, races, or ecotypes native to southwestern U.S. for salinity tolerance and mycorrhizal responsiveness. As expected, the taxa tested showed a wide range of responses to salinity and mycorrhizal fungi. This variation also occurred between ecotypes or races of the same species, indicating that seed collected from high-salinity reference systems is likely better adapted to harsh conditions than seed originating from less saline environments. All species tested had a positive or neutral response to mycorrhizal inoculation. We found no clear evidence that mycorrhizae increased salinity tolerance, but some species were so dependent on mycorrhizal fungi that they grew poorly at all salinity levels in pasteurized soil. ?? 2009 Elsevier B.V.

The effect of landscape complexity and microclimate on the thermal tolerance of a pest insect.

PubMed

Alford, Lucy; Tougeron, Kévin; Pierre, Jean-Sébastien; Burel, Françoise; van Baaren, Joan

2017-03-21

Landscape changes are known to exacerbate the impacts of climate change. As such, understanding the combined effect of climate and landscape on agroecosystems is vital if we are to maintain the function of agroecosystems. This study aimed to elucidate the effects of agricultural landscape complexity on the microclimate and thermal tolerance of an aphid pest to better understand how landscape and climate may interact to affect the thermal tolerance of pest species within the context of global climate change. Meteorological data were measured at the landscape level, and cereal aphids (Sitobion avenae, Metopolophium dirhodum and Rhopalosiphum padi) sampled, from contrasting landscapes (simple and complex) in winter 2013/2014 and spring 2014 in cereal fields of Brittany, France. Aphids were returned to the laboratory and the effect of landscape of origin on aphid cold tolerance (as determined by CT min ) was investigated. Results revealed that local landscape complexity significantly affected microclimate, with simple homogenous landscapes being on average warmer, but with greater temperature variation. Landscape complexity was shown to impact aphid cold tolerance, with aphids from complex landscapes being more cold tolerant than those from simple landscapes in both winter and spring, but with differences among species. This study highlights that future changes to land use could have implications for the thermal tolerance and adaptability of insects. Furthermore, not all insect species respond in a similar way to microhabitat and microclimate, which could disrupt important predator-prey relationships and the ecosystem service they provide. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Crayfish Impact Desert River Ecosystem Function and Litter-Dwelling Invertebrate Communities through Association with Novel Detrital Resources

PubMed Central

Moody, Eric K.; Sabo, John L.

2013-01-01

Shifts in plant species distributions due to global change are increasing the availability of novel resources in a variety of ecosystems worldwide. In semiarid riparian areas, hydric pioneer tree species are being replaced by drought-tolerant plant species as water availability decreases. Additionally, introduced omnivorous crayfish, which feed upon primary producers, allochthonous detritus, and benthic invertebrates, can impact communities at multiple levels through both direct and indirect effects mediated by drought-tolerant plants. We tested the impact of both virile crayfish (Orconectes virilis) and litter type on benthic invertebrates and the effect of crayfish on detrital resources across a gradient of riparian vegetation drought-tolerance using field cages with leaf litter bags in the San Pedro River in Southeastern Arizona. Virile crayfish increased breakdown rate of novel drought-tolerant saltcedar (Tamarix ramosissima), but did not impact breakdown of drought-tolerant seepwillow (Baccharis salicifolia) or hydric Fremont cottonwood (Populus fremontii) and Gooding's willow (Salix goodingii). Effects on invertebrate diversity were observed at the litter bag scale, but no effects were found at the cage scale. Crayfish decreased alpha diversity of colonizing macroinvertebrates, but did not affect beta diversity. In contrast, the drought-tolerant litter treatment decreased beta diversity relative to hydric litter. As drought-tolerant species become more abundant in riparian zones, their litter will become a larger component of the organic matter budget of desert streams which may serve to homogenize the litter-dwelling community and support elevated populations of virile crayfish. Through impacts at multiple trophic levels, crayfish have a significant effect on desert stream ecosystems. PMID:23667600

Heat or cold priming-induced cross-tolerance to abiotic stresses in plants: key regulators and possible mechanisms.

PubMed

Hossain, Mohammad Anwar; Li, Zhong-Guang; Hoque, Tahsina Sharmin; Burritt, David J; Fujita, Masayuki; Munné-Bosch, Sergi

2018-01-01

Plants growing under field conditions are constantly exposed, either simultaneously or sequentially, to more than one abiotic stress factor. Plants have evolved sophisticated sensory systems to perceive a number of stress signals that allow them to activate the most adequate response to grow and survive in a given environment. Recently, cross-stress tolerance (i.e. tolerance to a second, strong stress after a different type of mild primary stress) has gained attention as a potential means of producing stress-resistant crops to aid with global food security. Heat or cold priming-induced cross-tolerance is very common in plants and often results from the synergistic co-activation of multiple stress signalling pathways, which involve reactive nitrogen species (RNS), reactive oxygen species (ROS), reactive carbonyl species (RCS), plant hormones and transcription factors. Recent studies have shown that the signalling functions of ROS, RNS and RCS, most particularly hydrogen peroxide, nitric oxide (NO) and methylglyoxal (MG), provide resistance to abiotic stresses and underpin cross-stress tolerance in plants by modulating the expression of genes as well as the post-translational modification of proteins. The current review highlights the key regulators and mechanisms underlying heat or cold priming-induced cross-stress tolerance in plants, with a focus on ROS, MG and NO signalling, as well as on the role of antioxidant and glyoxalase systems, osmolytes, heat-shock proteins (HSPs) and hormones. Our aim is also to provide a comprehensive idea on the topic for researchers using heat or cold priming-induced cross-tolerance as a mechanism to improve crop yields under multiple abiotic stresses.

The GED4GEM project: development of a Global Exposure Database for the Global Earthquake Model initiative

USGS Publications Warehouse

Gamba, P.; Cavalca, D.; Jaiswal, K.S.; Huyck, C.; Crowley, H.

2012-01-01

In order to quantify earthquake risk of any selected region or a country of the world within the Global Earthquake Model (GEM) framework (www.globalquakemodel.org/), a systematic compilation of building inventory and population exposure is indispensable. Through the consortium of leading institutions and by engaging the domain-experts from multiple countries, the GED4GEM project has been working towards the development of a first comprehensive publicly available Global Exposure Database (GED). This geospatial exposure database will eventually facilitate global earthquake risk and loss estimation through GEM’s OpenQuake platform. This paper provides an overview of the GED concepts, aims, datasets, and inference methodology, as well as the current implementation scheme, status and way forward.

Quantification of habitat fragmentation reveals extinction risk in terrestrial mammals

PubMed Central

Crooks, Kevin R.; Burdett, Christopher L.; Theobald, David M.; King, Sarah R. B.; Rondinini, Carlo; Boitani, Luigi

2017-01-01

Although habitat fragmentation is often assumed to be a primary driver of extinction, global patterns of fragmentation and its relationship to extinction risk have not been consistently quantified for any major animal taxon. We developed high-resolution habitat fragmentation models and used phylogenetic comparative methods to quantify the effects of habitat fragmentation on the world’s terrestrial mammals, including 4,018 species across 26 taxonomic Orders. Results demonstrate that species with more fragmentation are at greater risk of extinction, even after accounting for the effects of key macroecological predictors, such as body size and geographic range size. Species with higher fragmentation had smaller ranges and a lower proportion of high-suitability habitat within their range, and most high-suitability habitat occurred outside of protected areas, further elevating extinction risk. Our models provide a quantitative evaluation of extinction risk assessments for species, allow for identification of emerging threats in species not classified as threatened, and provide maps of global hotspots of fragmentation for the world’s terrestrial mammals. Quantification of habitat fragmentation will help guide threat assessment and strategic priorities for global mammal conservation. PMID:28673992

Satellite data based method for general survey of forest insect disturbance in British Columbia

NASA Astrophysics Data System (ADS)

Ranson, J.; Montesano, P.

2008-12-01

Regional forest disturbances caused by insects are important to monitor and quantify because of their influence on local ecosystems and the global carbon cycle. Local damage to forest trees disrupts food supplies and shelter for a variety of organisms. Changes in the global carbon budget, its sources and its sinks affect the way the earth functions as a whole, and has an impact on global climate. Furthermore, the ability to detect nascent outbreaks and monitor the spread of regional infestations helps managers mitigate the damage done by catastrophic insect outbreaks. While detection is needed at a fine scale to support local mitigation efforts, detection at a broad regional scale is important for carbon flux modeling on the landscape scale, and needed to direct the local efforts. This paper presents a method for routinely detecting insect damage to coniferous forests using MODIS vegetation indices, thermal anomalies and land cover. The technique is validated using insect outbreak maps and accounts for fire disturbance effects. The range of damage detected may be used to interpret and quantify possible forest damage by insects.

Quantifying Climate Feedbacks from Abrupt Changes in High-Latitude Trace-Gas Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlosser, Courtney Adam; Walter-Anthony, Katey; Zhuang, Qianlai

2013-04-26

Our overall goal was to quantify the potential for threshold changes in natural emission rates of trace gases, particularly methane and carbon dioxide, from pan-arctic terrestrial systems under the spectrum of anthropogenically forced climate warming, and the extent to which these emissions provide a strong feedback mechanism to global climate warming. This goal is motivated under the premise that polar amplification of global climate warming will induce widespread thaw and degradation of the permafrost, and would thus cause substantial changes in the extent of wetlands and lakes, especially thermokarst (thaw) lakes, over the Arctic. Through a coordinated effort of fieldmore » measurements, model development, and numerical experimentation with an integrated assessment model framework, we have investigated the following hypothesis: There exists a climate-warming threshold beyond which permafrost degradation becomes widespread and thus instigates strong and/or sharp increases in methane emissions (via thermokarst lakes and wetland expansion). These would outweigh any increased uptake of carbon (e.g. from peatlands) and would result in a strong, positive feedback to global climate warming.« less

Quantification of habitat fragmentation reveals extinction risk in terrestrial mammals.

PubMed

Crooks, Kevin R; Burdett, Christopher L; Theobald, David M; King, Sarah R B; Di Marco, Moreno; Rondinini, Carlo; Boitani, Luigi

2017-07-18

Although habitat fragmentation is often assumed to be a primary driver of extinction, global patterns of fragmentation and its relationship to extinction risk have not been consistently quantified for any major animal taxon. We developed high-resolution habitat fragmentation models and used phylogenetic comparative methods to quantify the effects of habitat fragmentation on the world's terrestrial mammals, including 4,018 species across 26 taxonomic Orders. Results demonstrate that species with more fragmentation are at greater risk of extinction, even after accounting for the effects of key macroecological predictors, such as body size and geographic range size. Species with higher fragmentation had smaller ranges and a lower proportion of high-suitability habitat within their range, and most high-suitability habitat occurred outside of protected areas, further elevating extinction risk. Our models provide a quantitative evaluation of extinction risk assessments for species, allow for identification of emerging threats in species not classified as threatened, and provide maps of global hotspots of fragmentation for the world's terrestrial mammals. Quantification of habitat fragmentation will help guide threat assessment and strategic priorities for global mammal conservation.

Quantifying Biodiversity Losses Due to Human Consumption: A Global-Scale Footprint Analysis.

PubMed

Wilting, Harry C; Schipper, Aafke M; Bakkenes, Michel; Meijer, Johan R; Huijbregts, Mark A J

2017-03-21

It is increasingly recognized that human consumption leads to considerable losses of biodiversity. This study is the first to systematically quantify these losses in relation to land use and greenhouse gas (GHG) emissions associated with the production and consumption of (inter)nationally traded goods and services by presenting consumption-based biodiversity losses, in short biodiversity footprint, for 45 countries and world regions globally. Our results showed that (i) the biodiversity loss per citizen shows large variations among countries, with higher values when per-capita income increases; (ii) the share of biodiversity losses due to GHG emissions in the biodiversity footprint increases with income; (iii) food consumption is the most important driver of biodiversity loss in most of the countries and regions, with a global average of 40%; (iv) more than 50% of the biodiversity loss associated with consumption in developed economies occurs outside their territorial boundaries; and (v) the biodiversity footprint per dollar consumed is lower for wealthier countries. The insights provided by our analysis might support policymakers in developing adequate responses to avert further losses of biodiversity when population and incomes increase. Both the mitigation of GHG emissions and land use related reduction options in production and consumption should be considered in strategies to protect global biodiversity.

Quantified carbon input for maintaining existing soil organic carbon stocks in global wheat systems

NASA Astrophysics Data System (ADS)

Wang, G.

2017-12-01

Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1°× 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha-1 yr-1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.

Quantifying and modeling long-range cross correlations in multiple time series with applications to world stock indices

NASA Astrophysics Data System (ADS)

Wang, Duan; Podobnik, Boris; Horvatić, Davor; Stanley, H. Eugene

2011-04-01

We propose a modified time lag random matrix theory in order to study time-lag cross correlations in multiple time series. We apply the method to 48 world indices, one for each of 48 different countries. We find long-range power-law cross correlations in the absolute values of returns that quantify risk, and find that they decay much more slowly than cross correlations between the returns. The magnitude of the cross correlations constitutes “bad news” for international investment managers who may believe that risk is reduced by diversifying across countries. We find that when a market shock is transmitted around the world, the risk decays very slowly. We explain these time-lag cross correlations by introducing a global factor model (GFM) in which all index returns fluctuate in response to a single global factor. For each pair of individual time series of returns, the cross correlations between returns (or magnitudes) can be modeled with the autocorrelations of the global factor returns (or magnitudes). We estimate the global factor using principal component analysis, which minimizes the variance of the residuals after removing the global trend. Using random matrix theory, a significant fraction of the world index cross correlations can be explained by the global factor, which supports the utility of the GFM. We demonstrate applications of the GFM in forecasting risks at the world level, and in finding uncorrelated individual indices. We find ten indices that are practically uncorrelated with the global factor and with the remainder of the world indices, which is relevant information for world managers in reducing their portfolio risk. Finally, we argue that this general method can be applied to a wide range of phenomena in which time series are measured, ranging from seismology and physiology to atmospheric geophysics.

Quantifying and modeling long-range cross correlations in multiple time series with applications to world stock indices.

PubMed

Wang, Duan; Podobnik, Boris; Horvatić, Davor; Stanley, H Eugene

2011-04-01

We propose a modified time lag random matrix theory in order to study time-lag cross correlations in multiple time series. We apply the method to 48 world indices, one for each of 48 different countries. We find long-range power-law cross correlations in the absolute values of returns that quantify risk, and find that they decay much more slowly than cross correlations between the returns. The magnitude of the cross correlations constitutes "bad news" for international investment managers who may believe that risk is reduced by diversifying across countries. We find that when a market shock is transmitted around the world, the risk decays very slowly. We explain these time-lag cross correlations by introducing a global factor model (GFM) in which all index returns fluctuate in response to a single global factor. For each pair of individual time series of returns, the cross correlations between returns (or magnitudes) can be modeled with the autocorrelations of the global factor returns (or magnitudes). We estimate the global factor using principal component analysis, which minimizes the variance of the residuals after removing the global trend. Using random matrix theory, a significant fraction of the world index cross correlations can be explained by the global factor, which supports the utility of the GFM. We demonstrate applications of the GFM in forecasting risks at the world level, and in finding uncorrelated individual indices. We find ten indices that are practically uncorrelated with the global factor and with the remainder of the world indices, which is relevant information for world managers in reducing their portfolio risk. Finally, we argue that this general method can be applied to a wide range of phenomena in which time series are measured, ranging from seismology and physiology to atmospheric geophysics.

Probabilistic Physics-Based Risk Tools Used to Analyze the International Space Station Electrical Power System Output

NASA Technical Reports Server (NTRS)

Patel, Bhogila M.; Hoge, Peter A.; Nagpal, Vinod K.; Hojnicki, Jeffrey S.; Rusick, Jeffrey J.

2004-01-01

This paper describes the methods employed to apply probabilistic modeling techniques to the International Space Station (ISS) power system. These techniques were used to quantify the probabilistic variation in the power output, also called the response variable, due to variations (uncertainties) associated with knowledge of the influencing factors called the random variables. These uncertainties can be due to unknown environmental conditions, variation in the performance of electrical power system components or sensor tolerances. Uncertainties in these variables, cause corresponding variations in the power output, but the magnitude of that effect varies with the ISS operating conditions, e.g. whether or not the solar panels are actively tracking the sun. Therefore, it is important to quantify the influence of these uncertainties on the power output for optimizing the power available for experiments.

The micro-mechanics of strength, durability and damage tolerance in composites: new insights from high resolution computed tomography

NASA Astrophysics Data System (ADS)

Spearing, S. Mark; Sinclair, Ian

2016-07-01

Recent work, led by the authors, on impact damage resistance, particle toughening and tensile fibre failure is reviewed in order to illustrate the use of high-resolution X-ray tomography to observe and quantify damage mechanisms in carbon fibre composite laminates. Using synchrotron and micro-focus X-ray sources resolutions of less than 1 μm have been routinely achieved. This enables individual broken fibres and the micromechanisms of particle toughening to be observed and quantified. The data for fibre failure, cluster formation and overall tensile strength are compared with model predictions. This allows strategies for future model development to be identified. The overall implications for using such high-resolution 3-D measurements to inform a “data-rich mechanics” approach to materials evaluation and modeling is discussed.

Quantifying the magnitude of torque physiotherapists apply when stretching the hamstring muscles of people with spinal cord injury.

PubMed

Harvey, Lisa A; McQuade, Lea; Hawthorne, Scott; Byak, Adrian

2003-07-01

To quantify the magnitude of stretch that physiotherapists apply to the hamstring muscles of people with spinal cord injury (SCI). Repeated-measures design. SCI unit in Australia. Fifteen individuals with motor complete paraplegia or tetraplegia. Twelve physiotherapists manually administered a stretch to the hamstring muscles of each subject. The stretch was applied by flexing the hip with the knee extended. Applied hip flexor torque. Therapists applied median hip flexor torques of between 30 and 68Nm, although some torques were as large as 121Nm. The stretch applied by different therapists to any 1 subject varied as much as 40-fold. There is a large range of stretch torques provided by physiotherapists to patients with SCI. Some therapists provide stretch torques well in excess of those tolerated by individuals with intact sensation.

Understanding the Mechanism of Thermotolerance Distinct From Heat Shock Response Through Proteomic Analysis of Industrial Strains of Saccharomyces cerevisiae*

PubMed Central

Shui, Wenqing; Xiong, Yun; Xiao, Weidi; Qi, Xianni; Zhang, Yong; Lin, Yuping; Guo, Yufeng; Zhang, Zhidan; Wang, Qinhong; Ma, Yanhe

2015-01-01

Saccharomyces cerevisiae has been intensively studied in responses to different environmental stresses such as heat shock through global omic analysis. However, the S. cerevisiae industrial strains with superior thermotolerance have not been explored in any proteomic studies for elucidating the tolerance mechanism. Recently a new diploid strain was obtained through evolutionary engineering of a parental industrial strain, and it exhibited even higher resistance to prolonged thermal stress. Herein, we performed iTRAQ-based quantitative proteomic analysis on both the parental and evolved industrial strains to further understand the mechanism of thermotolerant adaptation. Out of ∼2600 quantifiable proteins from biological quadruplicates, 193 and 204 proteins were differentially regulated in the parental and evolved strains respectively during heat-stressed growth. The proteomic response of the industrial strains cultivated under prolonged thermal stress turned out to be substantially different from that of the laboratory strain exposed to sudden heat shock. Further analysis of transcription factors underlying the proteomic perturbation also indicated the distinct regulatory mechanism of thermotolerance. Finally, a cochaperone Mdj1 and a metabolic enzyme Adh1 were selected to investigate their roles in mediating heat-stressed growth and ethanol production of yeasts. Our proteomic characterization of the industrial strain led to comprehensive understanding of the molecular basis of thermotolerance, which would facilitate future improvement in the industrially important trait of S. cerevisiae by rational engineering. PMID:25926660

Effect of Global ATGL Knockout on Murine Fasting Glucose Kinetics.

PubMed

Coelho, Margarida; Nunes, Patricia; Mendes, Vera M; Manadas, Bruno; Heerschap, Arend; Jones, John G

2015-01-01

Mice deficient in adipose triglyceride lipase (ATGL(-/-)) present elevated ectopic lipid levels but are paradoxically glucose-tolerant. Measurement of endogenous glucose production (EGP) and Cori cycle activity provide insights into the maintenance of glycemic control in these animals. These parameters were determined in 7 wild-type (ATGL(+/-)) and 6 ATGL(-/-) mice by a primed-infusion of [U-(13)C6]glucose followed by LC-MS/MS targeted mass-isotopomer analysis of blood glucose. EGP was quantified by isotope dilution of [U-(13)C6]glucose while Cori cycling was estimated by analysis of glucose triose (13)C-isotopomers. Fasting plasma free fatty-acids were significantly lower in ATGL(-/-) versus control mice (0.43 ± 0.05 mM versus 0.73 ± 0.11 mM, P < 0.05). Six-hour fasting EGP rates were identical for both ATGL(-/-) and control mice (79 ± 11 versus 71 ± 7 μmol/kg/min, resp.). Peripheral glucose metabolism was dominated by Cori cycling (80 ± 2% and 82 ± 7% of glucose disposal for ATGL(-/-) and control mice, resp.) indicating that peripheral glucose oxidation was not significantly upregulated in ATGL(-/-) mice under these conditions. The glucose (13)C-isotopomer distributions in both ATGL(-/-) and control mice were consistent with extensive hepatic pyruvate recycling. This suggests that gluconeogenic outflow from the Krebs cycle was also well compensated in ATGL(-/-) mice.

Tip clearance effects on loads and performances of semi-open impeller centrifugal pumps at different specific speeds

NASA Astrophysics Data System (ADS)

Boitel, G.; Fedala, D.; Myon, N.

2016-11-01

Relevant industrial standards or customer's specifications could strictly forbid any device adjusting the axial rotor/stator position, so that tip clearance between semi-open impeller and casing might become a result of the pump machining tolerances and assembling process, leading to big tip clearance variations compared to its nominal value. Consequently, large disparities of global performances (head, power, efficiency) and axial loads are observed with high risk of both specifications noncompliance and bearing damages. This work aims at quantifying these variations by taking into account tip clearance value and pump specific speed. Computational Fluid Dynamics is used to investigate this phenomenon by means of steady simulations led on a semi-open centrifugal pump numerical model including secondary flows, based on a k-omega SST turbulence model. Four different specific speed pump sizes are simulated (from 8 to 50, SI units), with three tip clearances for each size on a wide flow range (from 40% to 120% of the best efficiency point). The numerical results clearly show that head, power and efficiency increase as the tip clearance decreases for the whole flow range. This effect is more significant when the specific speed is low. Meanwhile, the resulting axial thrust on the impeller is very sensitive to the tip clearance and can even lead to direction inversion.

Noncorticosteroid Combination Shampoo versus 1% Ketoconazole Shampoo for the Management of Mild-to-Moderate Seborrheic Dermatitis of the Scalp: Results from a Randomized, Investigator-Single-Blind Trial Using Clinical and Trichoscopic Evaluation

PubMed Central

Dall'Oglio, Federica; Lacarrubba, Francesco; Verzì, Anna Elisa; Micali, Giuseppe

2016-01-01

Purpose The aim of this study was to assess the efficacy and tolerability of a combination noncorticosteroid, antiinflammatory/antifungal shampoo versus 1% ketoconazole shampoo in the treatment of mild-to-moderate scalp seborrheic dermatitis (SD). Procedures Twenty patients were randomized to using the combination shampoo (group A, 10 patients) or the 1% ketoconazole shampoo (group B, 10 patients) 3 times a week every other day for 8 weeks. Efficacy was evaluated by measuring the degree of scaling and pruritus by clinical and trichoscopic examination using a 4-point scale. Additionally, a physician global assessment (PGA) was assessed at the end of the study. Results At 4 weeks, there was a significant reduction of scaling from baseline for both groups, while pruritus showed a significant reduction only for group A. After 8 weeks, there was a significant reduction of scaling and pruritus for both groups. PGA showed a complete response in 90% of the cases in both groups. Conclusions The results of our study demonstrate that the combination noncorticosteroid, antiinflammatory/antifungal shampoo represents an alternative approach to standard topical treatment for scalp SD. A noncorticosteroid shampoo may be equally safe and effective as ketoconazole shampoo for scalp SD, and trichoscopy provides accurate and reliable quantifiable data to assist in therapeutic monitoring. PMID:27171495

Noncorticosteroid Combination Shampoo versus 1% Ketoconazole Shampoo for the Management of Mild-to-Moderate Seborrheic Dermatitis of the Scalp: Results from a Randomized, Investigator-Single-Blind Trial Using Clinical and Trichoscopic Evaluation.

PubMed

Dall'Oglio, Federica; Lacarrubba, Francesco; Verzì, Anna Elisa; Micali, Giuseppe

2016-02-01

The aim of this study was to assess the efficacy and tolerability of a combination noncorticosteroid, antiinflammatory/antifungal shampoo versus 1% ketoconazole shampoo in the treatment of mild-to-moderate scalp seborrheic dermatitis (SD). Twenty patients were randomized to using the combination shampoo (group A, 10 patients) or the 1% ketoconazole shampoo (group B, 10 patients) 3 times a week every other day for 8 weeks. Efficacy was evaluated by measuring the degree of scaling and pruritus by clinical and trichoscopic examination using a 4-point scale. Additionally, a physician global assessment (PGA) was assessed at the end of the study. At 4 weeks, there was a significant reduction of scaling from baseline for both groups, while pruritus showed a significant reduction only for group A. After 8 weeks, there was a significant reduction of scaling and pruritus for both groups. PGA showed a complete response in 90% of the cases in both groups. The results of our study demonstrate that the combination noncorticosteroid, antiinflammatory/antifungal shampoo represents an alternative approach to standard topical treatment for scalp SD. A noncorticosteroid shampoo may be equally safe and effective as ketoconazole shampoo for scalp SD, and trichoscopy provides accurate and reliable quantifiable data to assist in therapeutic monitoring.

Demonstration of qubit operations below a rigorous fault tolerance threshold with gate set tomography

DOE PAGES

Blume-Kohout, Robin; Gamble, John King; Nielsen, Erik; ...

2017-02-15

Quantum information processors promise fast algorithms for problems inaccessible to classical computers. But since qubits are noisy and error-prone, they will depend on fault-tolerant quantum error correction (FTQEC) to compute reliably. Quantum error correction can protect against general noise if—and only if—the error in each physical qubit operation is smaller than a certain threshold. The threshold for general errors is quantified by their diamond norm. Until now, qubits have been assessed primarily by randomized benchmarking, which reports a different error rate that is not sensitive to all errors, and cannot be compared directly to diamond norm thresholds. Finally, we usemore » gate set tomography to completely characterize operations on a trapped-Yb +-ion qubit and demonstrate with greater than 95% confidence that they satisfy a rigorous threshold for FTQEC (diamond norm ≤6.7 × 10 -4).« less

5 MeV Proton irradiation effects on 200 GHz silicon-germanium heterojunction bipolar transistors

NASA Astrophysics Data System (ADS)

Gnana Prakash, A. P.; Hegde, Vinayakprasanna N.; Pradeep, T. M.; Pushpa, N.; Bajpai, P. K.; Patel, S. P.; Trivedi, Tarkeshwar; Cressler, J. D.

2017-12-01

The total dose effects of 5 MeV proton and Co-60 gamma irradiation in the dose range from 1 to 100 Mrad on advanced 200 GHz Silicon-Germanium heterojunction bipolar transistors (SiGe HBTs) are investigated. The SRIM simulation study was conducted to understand the energy loss of 5 MeV proton ions in SiGe HBT structure. Pre- and post-radiation DC figure of merits such as forward- and inverse-mode Gummel characteristics, excess base current, DC current gain and output characteristics were used to quantify the radiation tolerance of the devices. The results show that the proton creates a significant amount of damages in the surface and bulk of the transistor when compared with gamma irradiation. The SiGe HBTs shows robust ionizing radiation tolerance even up to a total dose of 100 Mrad for both radiations.

Probabilistic Methods for Structural Design and Reliability

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Whitlow, Woodrow, Jr. (Technical Monitor)

2002-01-01

This report describes a formal method to quantify structural damage tolerance and reliability in the presence of a multitude of uncertainties in turbine engine components. The method is based at the material behavior level where primitive variables with their respective scatter ranges are used to describe behavior. Computational simulation is then used to propagate the uncertainties to the structural scale where damage tolerance and reliability are usually specified. Several sample cases are described to illustrate the effectiveness, versatility, and maturity of the method. Typical results from this method demonstrate, that it is mature and that it can be used to probabilistically evaluate turbine engine structural components. It may be inferred from the results that the method is suitable for probabilistically predicting the remaining life in aging or in deteriorating structures, for making strategic projections and plans, and for achieving better, cheaper, faster products that give competitive advantages in world markets.

Lethal thermal maxima for age-0 pallid and shovelnose sturgeon: Implications for shallow water habitat restoration

USGS Publications Warehouse

Deslauriers, David; Heironimus, Laura B.; Chipps, Steven R.

2016-01-01

We evaluated temperature tolerance in age-0 pallid and shovelnose sturgeon (Scaphirhynchus albus and Scaphirhynchus platorynchus), two species that occur sympatrically in the Missouri and Mississippi Rivers. Fish (0.04–18 g) were acclimated to water temperatures of 13, 18 or 24 °C to quantify temperatures associated with lethal thermal maxima (LTM). The results show that no difference in thermal tolerance existed between the two sturgeon species, but that LTM was significantly related to body mass and acclimation temperature. Multiple linear regression analysis was used to estimate LTM, and outputs from the model were compared with water temperatures measured in the shallow water habitat (SWH) of the Missouri River. Observed SWH temperatures were not found to yield LTM conditions. The model developed here is to serve as a general guideline in the development of future SWH.

Mapping mutational effects along the evolutionary landscape of HIV envelope

PubMed Central

Hilton, Sarah K; Overbaugh, Julie

2018-01-01

The immediate evolutionary space accessible to HIV is largely determined by how single amino acid mutations affect fitness. These mutational effects can shift as the virus evolves. However, the prevalence of such shifts in mutational effects remains unclear. Here, we quantify the effects on viral growth of all amino acid mutations to two HIV envelope (Env) proteins that differ at >100 residues. Most mutations similarly affect both Envs, but the amino acid preferences of a minority of sites have clearly shifted. These shifted sites usually prefer a specific amino acid in one Env, but tolerate many amino acids in the other. Surprisingly, shifts are only slightly enriched at sites that have substituted between the Envs—and many occur at residues that do not even contact substitutions. Therefore, long-range epistasis can unpredictably shift Env’s mutational tolerance during HIV evolution, although the amino acid preferences of most sites are conserved between moderately diverged viral strains. PMID:29590010

Demonstration of qubit operations below a rigorous fault tolerance threshold with gate set tomography

PubMed Central

Blume-Kohout, Robin; Gamble, John King; Nielsen, Erik; Rudinger, Kenneth; Mizrahi, Jonathan; Fortier, Kevin; Maunz, Peter

2017-01-01

Quantum information processors promise fast algorithms for problems inaccessible to classical computers. But since qubits are noisy and error-prone, they will depend on fault-tolerant quantum error correction (FTQEC) to compute reliably. Quantum error correction can protect against general noise if—and only if—the error in each physical qubit operation is smaller than a certain threshold. The threshold for general errors is quantified by their diamond norm. Until now, qubits have been assessed primarily by randomized benchmarking, which reports a different error rate that is not sensitive to all errors, and cannot be compared directly to diamond norm thresholds. Here we use gate set tomography to completely characterize operations on a trapped-Yb+-ion qubit and demonstrate with greater than 95% confidence that they satisfy a rigorous threshold for FTQEC (diamond norm ≤6.7 × 10−4). PMID:28198466

Statistical analysis of QC data and estimation of fuel rod behaviour

NASA Astrophysics Data System (ADS)

Heins, L.; Groβ, H.; Nissen, K.; Wunderlich, F.

1991-02-01

The behaviour of fuel rods while in reactor is influenced by many parameters. As far as fabrication is concerned, fuel pellet diameter and density, and inner cladding diameter are important examples. Statistical analyses of quality control data show a scatter of these parameters within the specified tolerances. At present it is common practice to use a combination of superimposed unfavorable tolerance limits (worst case dataset) in fuel rod design calculations. Distributions are not considered. The results obtained in this way are very conservative but the degree of conservatism is difficult to quantify. Probabilistic calculations based on distributions allow the replacement of the worst case dataset by a dataset leading to results with known, defined conservatism. This is achieved by response surface methods and Monte Carlo calculations on the basis of statistical distributions of the important input parameters. The procedure is illustrated by means of two examples.

Mining the human gut microbiome for novel stress resistance genes

PubMed Central

Culligan, Eamonn P.; Marchesi, Julian R.; Hill, Colin; Sleator, Roy D.

2012-01-01

With the rapid advances in sequencing technologies in recent years, the human genome is now considered incomplete without the complementing microbiome, which outnumbers human genes by a factor of one hundred. The human microbiome, and more specifically the gut microbiome, has received considerable attention and research efforts over the past decade. Many studies have identified and quantified “who is there?,” while others have determined some of their functional capacity, or “what are they doing?” In a recent study, we identified novel salt-tolerance loci from the human gut microbiome using combined functional metagenomic and bioinformatics based approaches. Herein, we discuss the identified loci, their role in salt-tolerance and their importance in the context of the gut environment. We also consider the utility and power of functional metagenomics for mining such environments for novel genes and proteins, as well as the implications and possible applications for future research. PMID:22688726

Demonstration of qubit operations below a rigorous fault tolerance threshold with gate set tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blume-Kohout, Robin; Gamble, John King; Nielsen, Erik

Quantum information processors promise fast algorithms for problems inaccessible to classical computers. But since qubits are noisy and error-prone, they will depend on fault-tolerant quantum error correction (FTQEC) to compute reliably. Quantum error correction can protect against general noise if—and only if—the error in each physical qubit operation is smaller than a certain threshold. The threshold for general errors is quantified by their diamond norm. Until now, qubits have been assessed primarily by randomized benchmarking, which reports a different error rate that is not sensitive to all errors, and cannot be compared directly to diamond norm thresholds. Finally, we usemore » gate set tomography to completely characterize operations on a trapped-Yb +-ion qubit and demonstrate with greater than 95% confidence that they satisfy a rigorous threshold for FTQEC (diamond norm ≤6.7 × 10 -4).« less

Shifts in functional traits elevate risk of fire-driven tree dieback in tropical savanna and forest biomes.

PubMed

Pellegrini, Adam F A; Franco, Augusto C; Hoffmann, William A

2016-03-01

Numerous predictions indicate rising CO2 will accelerate the expansion of forests into savannas. Although encroaching forests can sequester carbon over the short term, increased fires and drought-fire interactions could offset carbon gains, which may be amplified by the shift toward forest plant communities more susceptible to fire-driven dieback. We quantify how bark thickness determines the ability of individual tree species to tolerate fire and subsequently determine the fire sensitivity of ecosystem carbon across 180 plots in savannas and forests throughout the 2.2-million km(2) Cerrado region in Brazil. We find that not accounting for variation in bark thickness across tree species underestimated carbon losses in forests by ~50%, totaling 0.22 PgC across the Cerrado region. The lower bark thicknesses of plant species in forests decreased fire tolerance to such an extent that a third of carbon gains during forest encroachment may be at risk of dieback if burned. These results illustrate that consideration of trait-based differences in fire tolerance is critical for determining the climate-carbon-fire feedback in tropical savanna and forest biomes. © 2015 John Wiley & Sons Ltd.

Necessity of early-stage verticalization in patients with brain and spinal cord injuries: Preliminary study.

PubMed

Daunoraviciene, Kristina; Adomaviciene, Ausra; Svirskis, Donatas; Griškevičius, Julius; Juocevicius, Alvydas

2018-05-18

Integration of the verticalization robot, Erigo, with functional electric stimulation and passive leg movements in the postacute rehabilitation of neurological patients could reduce the risk of secondary complications and improve functional outcomes (i.e. orthostatic hypotension, postural control and walking ability). The aim of this study was to estimate and quantify changes in the postacute stage, mainly related to heart rate and blood pressure in functional recovery, postural parameters, walking ability and psychoemotional reactions, during training using the verticalization robot Erigo. Six patients [three suffering from a stroke (ST) and three with spinal cord injuries (SCI)] participated in 10 sessions of physical therapy with the verticalization robot during primary inpatient rehabilitation. Functional state changes were assessed using clinical tests before and after the treatment, and the loading tolerance during Erigo training was noted. In early rehabilitation, Erigo training was safe and effective at improving orthostatic tolerance, posture and positive emotional reactions in both the ST and SCI patients (P< 0.05). In addition, advanced technologies were more effective at boosting the orthostatic tolerance in SCI patients, while they were more effective at increasing the dynamic balance and walking ability in ST patients (P< 0.05).

INSPECTION SHOP: PLAN TO PROVIDE UNCERTAINTY ANALYSIS WITH MEASUREMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nederbragt, W W

The LLNL inspection shop is chartered to make dimensional measurements of components for critical programmatic experiments. These measurements ensure that components are within tolerance and provide geometric details that can be used to further refine simulations. For these measurements to be useful, they must be significantly more accurate than the tolerances that are being checked. For example, if a part has a specified dimension of 100 millimeters and a tolerance of 1 millimeter, then the precision and/or accuracy of the measurement should be less than 1 millimeter. Using the ''10-to-1 gaugemaker's rule of thumb'', the desired precision of the measurementmore » should be less than 100 micrometers. Currently, the process for associating measurement uncertainty with data is not standardized, nor is the uncertainty based on a thorough uncertainty analysis. The goal of this project is to begin providing measurement uncertainty statements with critical measurements performed in the inspection shop. To accomplish this task, comprehensive knowledge about the underlying sources of uncertainty for measurement instruments need to be understood and quantified. Moreover, measurements of elemental uncertainties for each physical source need to be combined in a meaningful way to obtain an overall measurement uncertainty.« less

Quantitative nondestructive evaluation of materials and structures

NASA Technical Reports Server (NTRS)

Smith, Barry T.

1991-01-01

An experimental investigation was undertaken to quantify damage tolerance and resistance in composite materials impacted using the drop-weight method. Tests were conducted on laminates of several different carbon-fiber composite systems, such as epoxies, modified epoxies, and amorphous and semicrystalline thermoplastics. Impacted composite specimens were examined using destructive and non-destructive techniques to establish the characteristic damage states. Specifically, optical microscopy, ultrasonic, and scanning electron microscopy techniques were used to identify impact induced damage mechanisms. Damage propagation during post impact compression was also studied.

Pilot clinical trial of a robot-aided neuro-rehabilitation workstation with stroke patients

NASA Astrophysics Data System (ADS)

Krebs, Hermano I.; Hogan, Neville; Aisen, Mindy L.; Volpe, Bruce T.

1996-12-01

This paper summarizes our efforts to apply robotics and automation technology to assist, enhance, quantify, and document neuro-rehabilitation. It reviews a pilot clinical trial involving twenty stroke patients with a prototype robot-aided rehabilitation facility developed at MIT and tested at Burke Rehabilitation Hospital. In particular, we present a few results: (a) on the patient's tolerance of the procedure, (b) whether peripheral manipulation of the impaired limb influences brain recovery, (c) on the development of a robot-aided assessment procedure.

Phenological cues drive an apparent trade-off between freezing tolerance and growth in the family Salicaceae.

PubMed

Savage, Jessica A; Cavender-Bares, Jeannine

2013-08-01

With increasing concern about the ecological consequences of global climate change, there has been renewed interest in understanding the processes that determine species range limits. We tested a long-hypothesized trade-off between freezing tolerance and growth rate that is often used to explain species range limits. We grew 24 willow and poplar species (family Salicaceae) collected from across North America in a greenhouse common garden under two climate treatments. Maximum entropy models were used to describe species distributions and to estimate species-specific climate parameters. A range of traits related to freezing tolerance, including senescence, budburst, and susceptibility to different temperature minima during and after acclimation were measured. As predicted, species from colder climates exhibited higher freezing tolerance and slower growth rates than species from warmer climates under certain environmental conditions. However, the average relative growth rate (millimeters per meter per day) of northern species markedly increased when a subset of species was grown under a long summer day length (20.5 h), indicating that genetically based day-length cues are required for growth regulation in these species. We conclude that the observed relationship between freezing tolerance and growth rate is not driven by differences in species' intrinsic growth capacity but by differences in the environmental cues that trigger growth. We propose that the coordinated evolution of freezing tolerance and growth phenology could be important in circumscribing willow and poplar range limits and may have important implications for species' current and future distributions.

Achromobacter denitrificans Strain YD35 Pyruvate Dehydrogenase Controls NADH Production To Allow Tolerance to Extremely High Nitrite Levels

PubMed Central

Doi, Yuki; Shimizu, Motoyuki; Fujita, Tomoya; Nakamura, Akira; Takizawa, Noboru

2014-01-01

We identified the extremely nitrite-tolerant bacterium Achromobacter denitrificans YD35 that can grow in complex medium containing 100 mM nitrite (NO2−) under aerobic conditions. Nitrite induced global proteomic changes and upregulated tricarboxylate (TCA) cycle enzymes as well as antioxidant proteins in YD35. Transposon mutagenesis generated NO2−-hypersensitive mutants of YD35 that had mutations at genes for aconitate hydratase and α-ketoglutarate dehydrogenase in the TCA cycle and a pyruvate dehydrogenase (Pdh) E1 component, indicating the importance of TCA cycle metabolism to NO2− tolerance. A mutant in which the pdh gene cluster was disrupted (Δpdh mutant) could not grow in the presence of 100 mM NO2−. Nitrite decreased the cellular NADH/NAD+ ratio and the cellular ATP level. These defects were more severe in the Δpdh mutant, indicating that Pdh contributes to upregulating cellular NADH and ATP and NO2−-tolerant growth. Exogenous acetate, which generates acetyl coenzyme A and then is metabolized by the TCA cycle, compensated for these defects caused by disruption of the pdh gene cluster and those caused by NO2−. These findings demonstrate a link between NO2− tolerance and pyruvate/acetate metabolism through the TCA cycle. The TCA cycle mechanism in YD35 enhances NADH production, and we consider that this contributes to a novel NO2−-tolerating mechanism in this strain. PMID:24413603

Diversity, Super-Diversity, and Monolingual Language Ideology in the United States: Tolerance or Intolerance?

ERIC Educational Resources Information Center

Wiley, Terrence G.

2014-01-01

Each new demographic shift and economic or social change bring seemingly new issues into popular and political focus--questions, debates, and policies about the role of language in education and society and the recent claims that transnational migrations and globalization are resulting in unprecedented forms of ethnolinguisic…

Decreased CO2 availability and inactivation of Rubisco limit photosynthesis in cotton plants under heat and drought stress in the field

USDA-ARS?s Scientific Manuscript database

Heat and drought stresses are often coincident and constitute major factors limiting global crop yields. Selection of cultivars with superior tolerance to these stresses under production environments will facilitate efforts to improve yield and water use efficiencies in a climatically changing world...

Sustaining the future of plant breeding: The critical role of the USDA-ARS National Plant Germplasm System

USDA-ARS?s Scientific Manuscript database

Plant breeders require genetic diversity in their breeding programs to develop cultivars that are productive, nutritious, tolerant of biotic and abiotic stresses, and make efficient use of water and fertilizer. The USDA-ARS National Plant Germplasm System (NPGS) is a major source for global plant ge...

A Role Model in Light of Values: Mahatma Gandhi

ERIC Educational Resources Information Center

Dündar, Hakan; Erdogan, Erdi; Hareket, Erdem

2016-01-01

The non-violent, tolerant, pacifistic and humanistic manner of Mahatma Gandhi is a globally recognized fact. UNESCO's foundation of Mahatma Gandhi Institute of Education for Peace and Sustainable Development is one of the best examples that support this fact. In this study, it is aimed to present "Mahatma Gandhi", who is globally…

Simulation of Fault Tolerance in a Hypercube Arrangement of Discrete Processors.

DTIC Science & Technology

1987-12-01

Geometric Properties .................... 22 Binary Properties ....................... 26 Intel Hypercube Hardware Arrangement ... 28 IV. Cube-Connected... Properties of the CCC..............35 CCC Redundancy............................... 38 iii 6L V. Re-Configurable Cube-Connected Cycles ....... 40 Global...o........ 74 iv List of Figures Page Figure 1: Hypercubes of Different Dimensions ......... 21 Figure 2: Hypercube Properties

Quantitative trait loci mapping of heat tolerance in broccoli (Brassica oleracea var. italica) using genotyping-by-sequencing

USDA-ARS?s Scientific Manuscript database

Predicted rising global temperatures due to climate change have generated a demand for crops that are resistant to yield and quality losses from heat stress. Broccoli (Brassica oleracea var. italica) is a cool weather crop with high temperatures during production decreasing both head quality and yie...

Joint University Program for Air Transportation Research, 1985

NASA Technical Reports Server (NTRS)

Morrell, Frederick R. (Compiler)

1987-01-01

Air transportation research being carried on at the Massachusetts Institute of Technology, Princeton University, and Ohio University is discussed. Global Positioning System experiments, Loran-C monitoring, inertial navigation, the optimization of aircraft trajectories through severe microbursts, fault tolerant flight control systems, and expert systems for air traffic control are among the topics covered.

FACTORS CONTROLLING ZOSTERA MARINA L. GROWTH IN THE EASTERN AND WESTERN PACIFIC OCEAN: COMPARISONS BETWEEN SOUTH KOREA AND OREGON, USA

EPA Science Inventory

Zostera marina distribution is circum-global and tolerates a wide range of environmental conditions. Consequently, it is likely that populations have adapted to local environmental conditions of light, temperature and nutrient supply. We compared Z. marina growth dynamics over a ...

Transcriptome profiling and expression analyses of genes critical to wheat adaptation to low temperature

USDA-ARS?s Scientific Manuscript database

Background: To identify the genes involved in the development of low temperature (LT) tolerance in hexaploid wheat, we examined the global changes in expression in response to cold of the 55,052 potentially unique genes represented in the Affymetrix Wheat Genome microarray. We compared the expressi...

Global/local methods for probabilistic structural analysis

NASA Technical Reports Server (NTRS)

Millwater, H. R.; Wu, Y.-T.

1993-01-01

A probabilistic global/local method is proposed to reduce the computational requirements of probabilistic structural analysis. A coarser global model is used for most of the computations with a local more refined model used only at key probabilistic conditions. The global model is used to establish the cumulative distribution function (cdf) and the Most Probable Point (MPP). The local model then uses the predicted MPP to adjust the cdf value. The global/local method is used within the advanced mean value probabilistic algorithm. The local model can be more refined with respect to the g1obal model in terms of finer mesh, smaller time step, tighter tolerances, etc. and can be used with linear or nonlinear models. The basis for this approach is described in terms of the correlation between the global and local models which can be estimated from the global and local MPPs. A numerical example is presented using the NESSUS probabilistic structural analysis program with the finite element method used for the structural modeling. The results clearly indicate a significant computer savings with minimal loss in accuracy.

Global/local methods for probabilistic structural analysis

NASA Astrophysics Data System (ADS)

Millwater, H. R.; Wu, Y.-T.

1993-04-01

A probabilistic global/local method is proposed to reduce the computational requirements of probabilistic structural analysis. A coarser global model is used for most of the computations with a local more refined model used only at key probabilistic conditions. The global model is used to establish the cumulative distribution function (cdf) and the Most Probable Point (MPP). The local model then uses the predicted MPP to adjust the cdf value. The global/local method is used within the advanced mean value probabilistic algorithm. The local model can be more refined with respect to the g1obal model in terms of finer mesh, smaller time step, tighter tolerances, etc. and can be used with linear or nonlinear models. The basis for this approach is described in terms of the correlation between the global and local models which can be estimated from the global and local MPPs. A numerical example is presented using the NESSUS probabilistic structural analysis program with the finite element method used for the structural modeling. The results clearly indicate a significant computer savings with minimal loss in accuracy.

GlobTherm, a global database on thermal tolerances for aquatic and terrestrial organisms.

PubMed

Bennett, Joanne M; Calosi, Piero; Clusella-Trullas, Susana; Martínez, Brezo; Sunday, Jennifer; Algar, Adam C; Araújo, Miguel B; Hawkins, Bradford A; Keith, Sally; Kühn, Ingolf; Rahbek, Carsten; Rodríguez, Laura; Singer, Alexander; Villalobos, Fabricio; Ángel Olalla-Tárraga, Miguel; Morales-Castilla, Ignacio

2018-03-13

How climate affects species distributions is a longstanding question receiving renewed interest owing to the need to predict the impacts of global warming on biodiversity. Is climate change forcing species to live near their critical thermal limits? Are these limits likely to change through natural selection? These and other important questions can be addressed with models relating geographical distributions of species with climate data, but inferences made with these models are highly contingent on non-climatic factors such as biotic interactions. Improved understanding of climate change effects on species will require extensive analysis of thermal physiological traits, but such data are both scarce and scattered. To overcome current limitations, we created the GlobTherm database. The database contains experimentally derived species' thermal tolerance data currently comprising over 2,000 species of terrestrial, freshwater, intertidal and marine multicellular algae, plants, fungi, and animals. The GlobTherm database will be maintained and curated by iDiv with the aim to keep expanding it, and enable further investigations on the effects of climate on the distribution of life on Earth.

A New Local Bipolar Autoassociative Memory Based on External Inputs of Discrete Recurrent Neural Networks With Time Delay.

PubMed

Zhou, Caigen; Zeng, Xiaoqin; Luo, Chaomin; Zhang, Huaguang

In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.

Differential Modulation of Photosynthesis, Signaling, and Transcriptional Regulation between Tolerant and Sensitive Tomato Genotypes under Cold Stress

PubMed Central

Zhang, Junhong; Wang, Taotao; Li, Hanxia; Zhang, Yuyang; Yu, Chuying; Ye, Zhibiao

2012-01-01

The wild species Solanum habrochaites is more cold tolerant than the cultivated tomato (S. lycopersicum). To explore the mechanisms underlying cold tolerance of S. habrochaites, seedlings of S. habrochaites LA1777 introgression lines (ILs), as well as the two parents, were evaluated under low temperature (4°C). The IL LA3969 and its donor parent LA1777 were found to be more cold tolerant than the recurrent parent S. lycopersicum LA4024. The differences in physiology and global gene expression between cold-tolerant (LA1777 and LA3969) and -sensitive (LA4024) genotypes under cold stress were further investigated. Comparative transcriptome analysis identified 1613, 1456, and 1523 cold-responsive genes in LA1777, LA3969, and LA4024, respectively. Gene ontology (GO) term enrichment analysis revealed that more GO biological process terms were significantly enriched among the up-regulated genes in the two tolerant genotypes, whereas more biological processes were significantly repressed by cold stress in the sensitive one. A total of 92 genes with significant differential expression between tolerant and sensitive genotypes under cold stress were identified. Among these, many stress-related GO terms were significantly enriched, such as ‘response to stimulus’ and ‘response to stress’. Moreover, GO terms ‘response to hormone stimulus’, ‘response to reactive oxygen species (ROS)’, and ‘calcium-mediated signaling’ were also overrepresented. Several transcripts involved in hormone or ROS homeostasis were also differentially expressed. ROS, hormones, and calcium as signaling molecules may play important roles in regulating gene expression in response to cold stress. Moreover, the expression of various transcription factors, post-translational proteins, metabolic enzymes, and photosynthesis-related genes was also specifically modulated. These specific modifications may play pivotal roles in conferring cold tolerance in tomato. These results not only provide new insights into the molecular mechanisms of cold tolerance in tomato, but also provide potential candidate genes for genetic improvement. PMID:23226384

Serum lipid profiles, total tract nutrient digestibility, and gastrointestinal tolerance by dogs of α-cyclodextrin.

PubMed

Guevara, M A; Bauer, L L; Garleb, K A; Fahey, G C; de Godoy, M R C

2015-05-01

The objectives were to quantify gastrointestinal tolerance, total tract nutrient digestibility, and serum lipid profiles of dogs as affected by α-cyclodextrin (ACD) supplementation and to validate the accuracy of fat analyses techniques using novel ACD-fat complexes. The ACD was hydrolyzed and free sugars and hydrolyzed monosaccharides were quantified using high performance liquid chromatography. Known amount of fats were complexed with ACD, and fat content of complexes were determined using the ether extraction and acid-hydrolyzed fat methods. Nine mixed-breed hounds were used in a crossover design with 3 periods of 10 d each, including 6 d for diet adaptation and 4 d for fecal collection. Dogs were fed twice daily a diet with poultry byproduct meal and brewer's rice as the main ingredients, and chromic oxide (0.2%) was included as a digestion marker. Dogs were supplemented with either 0, 3, or 6 g of ACD diluted in 15 mL of water twice per day for a total of 0, 6, and 12 g ACD per day. The ACD had a very low free sugar concentration and, once hydrolyzed, released only glucose, as expected. Average daily food intake, fecal output (DM basis), and fecal scores were not significantly different among treatments. Body weight and condition score and serum triglycerides and cholesterol concentrations remained unaltered throughout the duration of the experiment. Dry matter, OM, and fat digestibility coefficients were lower (P < 0.05) for both treatment groups compared to the control. The acid-hydrolyzed fat method was valid to measure fat that was bound to ACD. Intake of ACD lowered fat digestibility somewhat but not to the extent previously reported, without affecting serum lipid concentrations or outcomes related to tolerance. Therefore, ACD supplementation resulted in a small decrease in fat digestibility, but ACD supplementation might have potential in modifying serum lipid profiles.

Drought stress limits the geographic ranges of two tree species via different physiological mechanisms.

PubMed

Anderegg, Leander D L; HilleRisLambers, Janneke

2016-03-01

Range shifts are among the most ubiquitous ecological responses to anthropogenic climate change and have large consequences for ecosystems. Unfortunately, the ecophysiological forces that constrain range boundaries are poorly understood, making it difficult to mechanistically project range shifts. To explore the physiological mechanisms by which drought stress controls dry range boundaries in trees, we quantified elevational variation in drought tolerance and in drought avoidance-related functional traits of a widespread gymnosperm (ponderosa pine - Pinus ponderosa) and angiosperm (trembling aspen - Populus tremuloides) tree species in the southwestern USA. Specifically, we quantified tree-to-tree variation in growth, water stress (predawn and midday xylem tension), drought avoidance traits (branch conductivity, leaf/needle size, tree height, leaf area-to-sapwood area ratio), and drought tolerance traits (xylem resistance to embolism, hydraulic safety margin, wood density) at the range margins and range center of each species. Although water stress increased and growth declined strongly at lower range margins of both species, ponderosa pine and aspen showed contrasting patterns of clinal trait variation. Trembling aspen increased its drought tolerance at its dry range edge by growing stronger but more carbon dense branch and leaf tissues, implying an increased cost of growth at its range boundary. By contrast, ponderosa pine showed little elevational variation in drought-related traits but avoided drought stress at low elevations by limiting transpiration through stomatal closure, such that its dry range boundary is associated with limited carbon assimilation even in average climatic conditions. Thus, the same climatic factor (drought) may drive range boundaries through different physiological mechanisms - a result that has important implications for process-based modeling approaches to tree biogeography. Further, we show that comparing intraspecific patterns of trait variation across ranges, something rarely done in a range-limit context, helps elucidate a mechanistic understanding of range constraints. © 2015 John Wiley & Sons Ltd.

Safety and tolerability of vortioxetine (15 and 20 mg) in patients with major depressive disorder: results of an open-label, flexible-dose, 52-week extension study.

PubMed

Jacobsen, Paula L; Harper, Linda; Chrones, Lambros; Chan, Serena; Mahableshwarkar, Atul R

2015-09-01

Vortioxetine is approved for the treatment of adults with major depressive disorder. This open-label extension (OLE) study evaluated the safety and tolerability of vortioxetine in the long-term treatment of major depressive disorder patients, as well as evaluated its effectiveness using measures of depression, anxiety, and overall functioning. This was a 52-week, flexible-dose, OLE study in patients who completed one of three randomized, double-blind, placebo-controlled, 8-week vortioxetine trials. All patients were switched to 10 mg/day vortioxetine for week 1, then adjusted between 15 and 20 mg for the remainder of the study, but not downtitrated below 15 mg. Safety and tolerability were assessed on the basis of treatment-emergent adverse events (TEAEs), vital signs, laboratory values, physical examination, and the Columbia-Suicide Severity Rating Scale. Efficacy measures included the Montgomery-Åsberg Depression Rating Scale, the Hamilton Anxiety Scale, the Clinical Global Impression Scale-Severity of Illness, and the Sheehan Disability Scale. Of the 1075 patients enrolled, 1073 received at least one dose of vortioxetine and 538 (50.0%) completed the study. A total of 537 patients withdrew early, with 115 (10.7% of the original study population) withdrawing because of TEAEs. Long-term treatment with vortioxetine was well tolerated; the most common TEAEs (≥10%) were nausea and headache. Laboratory values, vital signs, and physical examinations revealed no trends of clinical concern. The mean Montgomery-Åsberg Depression Rating Scale total score was 19.9 at the start of the extension study and 9.0 after 52 weeks of treatment (observed cases). Similar improvements were observed with the Hamilton Anxiety Scale (Δ-4.2), the Clinical Global Impression Scale-Severity of Illness (Δ-1.2), and the Sheehan Disability Scale (Δ-4.7) total scores after 52 weeks of treatment (observed case). In this 52-week, flexible-dose OLE study, 15 and 20 mg vortioxetine were safe and well tolerated. After entry into this study, patients continued to show improvement in depression and anxiety symptoms, as well as overall functioning, throughout the treatment period.