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1

Unpredictability and Context Conditioning: Does the Nature of the US Matter?  

PubMed

Using a conditioned suppression task, we examined the minimal conditions to establish context conditioning as induced by unpredictability of an unconditioned stimulus (US). We investigated whether a biologically significant US is necessary to produce such context conditioning effects. In this between-subjects experiment, we manipulated the nature of the US and US-unpredictability. In the Paired condition, the conditioned stimulus (CS) was always followed by the US, whereas in the Unpaired condition, the CS and the US were presented explicitly unpaired, that is, the CS was never followed by the US. Half of the participants received an aversive, biologically significant human scream, and the other half received a more neutral, biologically non-significant sound as US. Results show more contextual suppression in the Unpaired condition than in the Paired condition. We conclude that in an expectancy-based conditioning task, US-unpredictability, but not a biologically potent US, is crucial to establish context conditioning. PMID:23866242

Meulders, Ann; Boddez, Yannick; Vansteenwegen, Debora; Baeyens, Frank

2013-01-01

2

An animal model of anhedonia: attenuation of sucrose consumption and place preference conditioning by chronic unpredictable mild stress  

Microsoft Academic Search

Chronic exposure to very mild unpredictable stress has previously been found to depress the consumption of, and preference for, highly palatable sweet solutions. The present study used the place conditioning procedure to investigate whether these effects result from a decreased sensitivity to reward. Rats were subjected to chronic mild unpredictable stress for a total of 4 weeks. During weeks 3

Mariusz Papp; Paul Willner; Richard Muscat

1991-01-01

3

A New Tool for Assessing Context Conditioning Induced by US-Unpredictability in Humans: The Martians Task Restyled  

ERIC Educational Resources Information Center

Unpredictability of an unconditioned stimulus (US) typically produces context conditioning in animals and humans. We modified the Martians task--a computer game measuring learning of Pavlovian associations through conditioned suppression--for assessing context conditioning in humans. One between-subjects and one within-subjects study are reported.…

Meulders, Ann; Vervliet, Bram; Vansteenwegen, Debora; Hermans, Dirk; Baeyens, Frank

2011-01-01

4

A New Tool for Assessing Context Conditioning Induced by US-Unpredictability in Humans: The Martians Task Restyled  

ERIC Educational Resources Information Center

|Unpredictability of an unconditioned stimulus (US) typically produces context conditioning in animals and humans. We modified the Martians task--a computer game measuring learning of Pavlovian associations through conditioned suppression--for assessing context conditioning in humans. One between-subjects and one within-subjects study are…

Meulders, Ann; Vervliet, Bram; Vansteenwegen, Debora; Hermans, Dirk; Baeyens, Frank

2011-01-01

5

Intestinal pseudo-obstruction: An uncommon condition with heterogeneous etiology and unpredictable outcome  

PubMed Central

Intestinal pseudo-obstruction (IPO) either acute or chronic is a condition including features of intestinal ileus in absence of mechanical obstruction. Our paper presents such a rare case of idiopathic IPO in a 53-year-old male patient with recurrent episodes of pseudo-obstruction, which were successfully resolved by anticholinesterase agents, motilin agonists or colonic decompression. However, the patient finally underwent total colectomy. Huge colonic dilatation was identified intraoperatively, while histology showed a neuropathic variant of chronic intestinal pseudo-obstruction. Etiologic mechanisms and current therapeutic methods are reviewed in this paper, which concludes that IPO is a condition in which conservative treatment usually fails. Total colectomy with ileoanal pouch may be the only solution in these situations.

Georgescu, Eugen Florin; Vasile, Ion; Ionescu, Reanina

2008-01-01

6

The interplay of conditional NCAM-knockout and chronic unpredictable stress leads to increased aggression in mice.  

PubMed

Abstract The neural cell adhesion molecule (NCAM) is a key regulator of brain plasticity. Substantial evidence indicates that NCAM is down-regulated by exposure to sustained stress and chronic stress seems to lead to increased aggression. In addition, constitutional NCAM deletion in mice has been shown to lead to increased intermale aggression and altered emotionality Forebrain-specific postnatal NCAM knockout was previously shown to impair cognitive function, particularly when animals were exposed to subchronic stress, but the effects on emotional and social behavior remain unclear. In this study, we investigated the potential interplay of a forebrain-specific postnatal NCAM deletion and exposure to different lengths of repeated stress (i.e. subchronic: 14 days; chronic: 29 days) on aggressive and emotional behavior. Our results show that postnatal deletion of NCAM in the forebrain leads to increased aggression and altered emotionality depending on the duration of stress, whereas conditional NCAM knockout has no basal impact on these behaviors. These findings support the involvement of NCAM in the regulation of emotional and aggressive behaviors, suggesting that diminished NCAM expression might be a critical vulnerability factor for the development of these behavioral alterations under repeated exposure to stress. PMID:24010949

Kohl, Christine; Riccio, Orbicia; Grosse, Jocelyn; Zanoletti, Olivia; Fournier, Céline; Klampfl, Stefanie M; Schmidt, Mathias V; Sandi, Carmen

2013-11-01

7

Azerbaijan: environmental conditions and outlook.  

PubMed

The author describes present environmental conditions in Azerbaijan in relation to the Soviet legacy and measures taken since independence. Environmental projects have been financed largely by international organizations and foreign companies. The most serious problems are contaminants in the Caspian Sea; air, water, and soil pollution in Sumgait; illegal fishing; poor quality of drinking water; cutting of forests for fuel and pasture; overgrazing; and soil erosion and salinization. Progress in developing an environmental conscience, necessary for sustained protection of the environment, will depend most importantly on environmental education, growth of democratic institutions and attitudes that encourage both governmental and citizen responsibility for the environment, and economic development that produces a substantial middle class. Positive advances include a Constitution and laws that require protection of the environment, and individuals who speak out for environmental care. Negative factors include poverty and the present government's low priority for environmental protection. PMID:12956597

Shelton, Napier

2003-06-01

8

Increasing the independent responding of autistic children with unpredictable supervision.  

PubMed Central

We investigated the role of predictable versus unpredictable supervision on the independent task responding of three autistic children. In a predictable supervision condition, the therapist was present in the setting for a regular period of time and then was absent for the remainder of the session. In an unpredictable supervision condition, the therapist's presence was scheduled on a random, intermittent, and unpredictable basis throughout the session. The multiple baseline analysis showed that the unpredictable supervision produced much higher levels of on-task responding during the therapist's absence for all three children. Analysis of work completed during the therapist's absence also favored the unpredictable supervision condition. The results are discussed in relation to the literature on generalization and educational practice.

Dunlap, G; Johnson, J

1985-01-01

9

Interpreting the concept of joint unpredictability of asset returns: A distance approach  

NASA Astrophysics Data System (ADS)

This paper discusses the joint unpredictability of asset returns on two markets. It provides a necessary condition for joint unpredictability in term of distance between information sets. We conclude that the joint unpredictability requires a condition very strong and so, in this sense, it represents a “singularity”. The result should give a theoretical support to the empirical evidence in favor of the predictability of the returns.

Focker, Fulvia; Triacca, Umberto

2006-09-01

10

Immune Activity, Body Condition and Human-Associated Environmental Impacts in a Wild Marine Mammal  

PubMed Central

Within individuals, immunity may compete with other life history traits for resources, such as energy and protein, and the damage caused by immunopathology can sometimes outweigh the protective benefits that immune responses confer. However, our understanding of the costs of immunity in the wild and how they relate to the myriad energetic demands on free-ranging organisms is limited. The endangered Galapagos sea lion (Zalophus wollebaeki) is threatened simultaneously by disease from domestic animals and rapid changes in food availability driven by unpredictable environmental variation. We made use of this unique ecology to investigate the relationship between changes in immune activity and changes in body condition. We found that during the first three months of life, changes in antibody concentration were negatively correlated with changes in mass per unit length, skinfold thickness and serum albumin concentration, but only in a sea lion colony exposed to anthropogenic environmental impacts. It has previously been shown that changes in antibody concentration during early Galapagos sea lion development were higher in a colony exposed to anthropogenic environmental impacts than in a control colony. This study allows for the possibility that these relatively large changes in antibody concentration are associated with negative impacts on fitness through an effect on body condition. Our findings suggest that energy availability and the degree of plasticity in immune investment may influence disease risk in natural populations synergistically, through a trade-off between investment in immunity and resistance to starvation. The relative benefits of such investments may change quickly and unpredictably, which allows for the possibility that individuals fine-tune their investment strategies in response to changes in environmental conditions. In addition, our results suggest that anthropogenic environmental impacts may impose subtle energetic costs on individuals, which could contribute to population declines, especially in times of energy shortage.

Brock, Patrick M.; Hall, Ailsa J.; Goodman, Simon J.; Cruz, Marilyn; Acevedo-Whitehouse, Karina

2013-01-01

11

Prepare for Unpredictable Spring Weather  

MedlinePLUS

... CDC Features Current Features Breast Cancer Awareness Childhood Obesity Falls Prevention FoodCORE Got Mice? Know Hepatitis B ... 18, 2013 Content source: National Center for Environmental Health, Division of Environmental Hazards and Health Effects Page maintained by: Office of ...

12

Unpredictable Certainty. Information Infrastructure through 2000.  

National Technical Information Service (NTIS)

The authors have available an impressive array of information technology. They can transmit literature, movies, music, and talk. Government, businesses, and individuals are eager to go on-line to buy, sell, teach, learn, and more. The Unpredictable Certai...

1996-01-01

13

Cross-taxon congruence and environmental conditions  

PubMed Central

Background Diversity patterns of different taxa typically covary in space, a phenomenon called cross-taxon congruence. This pattern has been explained by the effect of one taxon diversity on taxon diversity, shared biogeographic histories of different taxa, and/or common responses to environmental conditions. A meta-analysis of the association between environment and diversity patterns found that in 83 out of 85 studies, more than 60% of the spatial variability in species richness was related to variables representing energy, water or their interaction. The role of the environment determining taxa diversity patterns leads us to hypothesize that this would explain the observed cross-taxon congruence. However, recent analyses reported the persistence of cross-taxon congruence when environmental effect was statistically removed. Here we evaluate this hypothesis, analyzing the cross-taxon congruence between birds and mammals in the Brazilian Cerrado, and assess the environmental role on the spatial covariation in diversity patterns. Results We found a positive association between avian and mammal richness and a positive latitudinal trend for both groups in the Brazilian Cerrado. Regression analyses indicated an effect of latitude, PET, and mean temperature over both biological groups. In addition, we show that NDVI was only associated with avian diversity; while the annual relative humidity, was only correlated with mammal diversity. We determined the environmental effects on diversity in a path analysis that accounted for 73% and 76% of the spatial variation in avian and mammal richness. However, an association between avian and mammal diversity remains significant. Indeed, the importance of this link between bird and mammal diversity was also supported by a significant association between birds and mammal spatial autoregressive model residuals. Conclusion Our study corroborates the main role of environmental conditions on diversity patterns, but suggests that other important mechanisms, which have not been properly evaluated, are involved in the observed cross-taxon congruence. The approaches introduced here indicate that the prevalence of a significant association among taxa, after considering the environmental determinant, could indicate both the need to incorporate additional processes (e.g. biogeographic and evolutionary history or trophic interactions) and/or the existence of a shared trend in detection biases among taxa and regions.

2010-01-01

14

Eliminating Unpredictable Variation through Iterated Learning  

ERIC Educational Resources Information Center

|Human languages may be shaped not only by the (individual psychological) processes of language acquisition, but also by population-level processes arising from repeated language learning and use. One prevalent feature of natural languages is that they avoid unpredictable variation. The current work explores whether linguistic predictability might…

Smith, Kenny; Wonnacott, Elizabeth

2010-01-01

15

78 FR 7850 - Sixty First Meeting: RTCA Special Committee 135, Environmental Conditions and Test Procedures for...  

Federal Register 2010, 2011, 2012, 2013

...Special Committee 135, Environmental Conditions and Test Procedures for...Special Committee 135, Environmental Conditions and Test Procedures for...Special Committee 135, Environmental Conditions and Test Procedures...

2013-02-04

16

77 FR 56253 - 60th Meeting: RTCA Special Committee 135, Environmental Conditions and Test Procedures for...  

Federal Register 2010, 2011, 2012, 2013

...Special Committee 135, Environmental Conditions and Test Procedures for...Special Committee 135, Environmental Conditions and Test Procedures for...Special Committee 135, Environmental Conditions and Test Procedures...

2012-09-12

17

Increase your fraud auditing effectiveness by being unpredictable!  

Microsoft Academic Search

Purpose – To identify how auditors can incorporate unpredictability into their audit plan in order to comply with both US and international auditing standards on the prevention and detection of fraud. Design\\/methodology\\/approach – Review of auditing standards, fraud cases, and other audit literature. Findings – A cost-benefit model for evaluating unpredictability and 17 specific ways that auditors can incorporate unpredictability.

Thomas E. McKee

2006-01-01

18

Anxious Responses to Predictable and Unpredictable Aversive Events  

Microsoft Academic Search

Anxiety induced by 2 types of predictable and unpredictable aversive stimuli, an unpleasant shock or a less aversive airblast to the larynx, were investigated in a between-group design. Participants anticipated predictable (signaled) or unpredictable (not signaled) aversive events, or no aversive event. Unpredictable, relative to predictable, contexts potentiated the startle reflex in the shock group but not in the airblast

Christian Grillon; Johanna P. Baas; Shmuel Lissek; Kathryn Smith; Jean Milstein

2004-01-01

19

Beyond Cumulative Risk: Distinguishing Harshness and Unpredictability as Determinants of Parenting and Early Life History Strategy  

ERIC Educational Resources Information Center

|Drawing on life history theory, Ellis and associates' (2009) recent across- and within-species analysis of ecological effects on reproductive development highlighted two fundamental dimensions of environmental variation and influence: harshness and unpredictability. To evaluate the unique contributions of these factors, the authors of present…

Belsky, Jay; Schlomer, Gabriel L.; Ellis, Bruce J.

2012-01-01

20

Conditional Probability Analysis: A Statistical Tool for Environmental Analysis.  

EPA Science Inventory

The use and application of environmental conditional probability analysis (CPA) is relatively recent. The first presentation using CPA was made in 2002 at the New England Association of Environmental Biologists Annual Meeting in Newport. Rhode Island. CPA has been used since the...

21

Effect of environmental conditions on the mechanical properties and ...  

Treesearch

Jul 21, 2013... before and after exposure to various environmental conditions for 60 days. ... deterioration of mechanical properties than those in high humidity or freezing ... Keywords: thermoplastic resin, polycaprolactone, wood flour, ...

22

ENVIRONMENTALLY FRIENDLIER ORGANIC TRANSFORMATIONS ON MINERAL SUPPORTS UNDER NONTRADITIONAL CONDITIONS  

EPA Science Inventory

Synthetic organic reactions performed under non-traditional conditions are gaining popularity primarily to circumvent the growing environmental concerns. A solvent-free approach that involves microwave (MW) exposure of neat reactants (undiluted) either in presence of a catalyst o...

23

Overview of environmental and hydrogeologic conditions at King Salmon, Alaska  

USGS Publications Warehouse

The Federal Aviation Administration is conducting preliminary environmental assessments at most of its present or former facilities in Alaska. Information about environmental conditions at King Salmon, Alaska are presented in this report. This report gives an overview of the geology, hydro- logy, and climate of the King Salmon area and describes general geohydrologic conditions. A thick alluvial aquifer underlies King Salmon and both ground water and surface water are plentiful in the area.

Waythomas, C. F.

1994-01-01

24

IR detector dewar and cooler assemblies for stringent environmental conditions  

NASA Astrophysics Data System (ADS)

Environmental conditions (thermal, vibrations and shocks) are key performance and reliability factors for designing IR detectors. To address these constraints Sofradir has developed specific concepts to make the IR detector more robust in stringent environmental conditions. This paper describes these design concepts that involve both the IRFPA (IR Focal Plane Array) and the cryogenics part, as well as the level of robustness that is achieved.

Molina, Marianne; Breniere, Xavier; Tribolet, Philippe

2007-05-01

25

Environmental conditions favoring ice pellet aggregation  

NASA Astrophysics Data System (ADS)

Winter precipitation is an important issue for many countries because of its common occurrence and its potential for destructive consequences. However, correct prediction of the precipitation type when temperatures are near 0 °C is often difficult because many different types can occur. These different precipitation types can occur alone, in close succession, or in combination. This study examines one aspect of this overall issue, the ability of ice pellets to form aggregates through collisions with supercooled drops and the consequent reduction of freezing raindrops at the surface. This issue was examined using a bin model (initiated with a Marshall-Palmer precipitation size distribution) to model the collisions between ice pellets and supercooled rain drops as they fall through a refreezing layer to the surface. Under certain conditions, collisions aloft resulting in ice pellet aggregates can significantly reduce the number of supercooled drops that reach the surface. For example, a reduction of supercooled drop precipitation rate of 56% is achieved in an initial overall precipitation rate of 25 mm/h and this in turn leads to 40% of the ice pellets at the surface being aggregated particles. Lower precipitation rates and a higher proportion of particles that contain ice at the top of the layer lead to a smaller reduction in precipitation rates but not necessarily a smaller fraction of aggregation. These findings imply that the likelihood of ice pellet aggregation must be accounted for in order to predict freezing rain intensity.

Carmichael, H. E.; Stewart, R. E.; Henson, W.; Thériault, J. M.

2011-09-01

26

Environmental Enteropathy: Critical implications of a poorly understood condition  

PubMed Central

Environmental enteropathy (also called tropical enteropathy) is a subclinical condition caused by constant fecal-oral contamination and resulting in blunting of intestinal villi and intestinal inflammation. Although these histological changes were discovered decades ago, the clinical impact of environmental enteropathy is just starting to be recognized. The failure of nutritional interventions and oral vaccines in the developing world may be attributed to environmental enteropathy, as the intestinal absorptive and immunologic functions are significantly deranged. Here we review the existing literature and examine potential mechanisms of pathogenesis for this poorly understood condition.

Korpe, Poonum S.; Petri, William A.

2012-01-01

27

Evolution, stress, and sensitive periods: the influence of unpredictability in early versus late childhood on sex and risky behavior.  

PubMed

According to a recent evolutionary life history model of development proposed by Ellis, Figueredo, Brumbach, and Schlomer (2009), growing up in harsh versus unpredictable environments should have unique effects on life history strategies in adulthood. Using data from the Minnesota Longitudinal Study of Risk and Adaptation, we tested how harshness and unpredictability experienced in early childhood (age 0-5) versus in later childhood (age 6-16) uniquely predicted sexual and risky behavior at age 23. Findings showed that the strongest predictor of both sexual and risky behavior was an unpredictable environment between ages 0 and 5. Individuals exposed to more unpredictable, rapidly changing environments during the first 5 years of life displayed a faster life history strategy at age 23 by having more sexual partners, engaging in more aggressive and delinquent behaviors, and being more likely to be associated with criminal activities. In contrast, exposure to either harsh environments or experiencing unpredictability in later childhood (age 6-16) was, for the most part, not significantly related to these outcomes at age 23. Viewed together, these findings show that unpredictable rather than merely harsh childhood environments exert unique effects on risky behavior later in life consistent with a faster life history strategy. The findings also suggest that there is a developmentally sensitive period for assessing environmental unpredictability during the first 5 years of life. PMID:22329381

Simpson, Jeffry A; Griskevicius, Vladas; Kuo, Sally I-Chun; Sung, Sooyeon; Collins, W Andrew

2012-02-13

28

Preexposure to (un)predictable shock modulates discriminative fear learning between cue and context: an investigation of the interaction between fear and anxiety.  

PubMed

It has been suggested that prior experiences with unpredictable/uncontrollable stressors facilitate subsequent fear learning and the development of anxiety disorders. However, animal research documents that preexposure to unpredictable stressors (USs) impede later fear conditioning with that US. These differential predictions were tested in a human experimental model of clinical anxiety. One (US-only) group was preexposed to unpredictable shocks, a second (Unpaired) group received explicitly unpaired presentations of a neutral shape and the shock, and a third (Paired) group received paired shape-shock presentations. Next, all groups received training with a novel shape, using the same shock (50% reinforcement). Fear responding was assessed through startle modulation and online shock-expectancy ratings. Results showed retarded fear learning in the unpredictable groups compared to the predictable group. We argue that prior experiences of unpredictability may still contribute to the development of clinical anxiety, by impeding adaptive fear learning and perpetuating the perception of unpredictability/uncontrollability. PMID:22349708

Meulders, Ann; Vervliet, Bram; Fonteyne, Riet; Baeyens, Frank; Hermans, Dirk; Vansteenwegen, Debora

2012-02-17

29

Effect of Space Environmental Conditions on Mechanical Properties of CFRP.  

National Technical Information Service (NTIS)

The effect of space environmental conditions on mechanical properties of CFRP was examined by two methodes: i.e. electron-beam radiation test and thermal-vacuum test. The electron-beam radiation test showed no change in the mechanical properties of CFRP i...

K. Sonoda

1984-01-01

30

Long-term sensitization and environmental conditioning in terrestrial snails  

Microsoft Academic Search

The hypothesis that a long-term increase of behavioural responses in snails (over a period of days) might be due to environmental conditioning was examined. Training consisted of delivering electric shocks non-contingently with test stimuli twice per day for 5 days to freely moving snails on a ball floating in water. After training, a significant difference in amplitude of a withdrawal

P. Balaban; N. Bravarenko

1993-01-01

31

Extracellular Factors of Bacterial Adaptation to Unfavorable Environmental Conditions  

Microsoft Academic Search

Data on extracellular compounds of bacteria involved in their adaptation to unfavorable environmental conditions are reviewed, including high or low temperatures, growth-inhibiting or bactericidal concentrations of toxic substances (oxidants, phenols, and heavy metals) and antibiotics, deviation of pH values from optimum levels, and salinity of the medium. Chemically, the compounds identified belong to diverse types (proteins, hydrocarbons, organic acids, nucleotides,

Yu. A. Nikolaev

2004-01-01

32

Effects of Harsh and Unpredictable Environments in Adolescence on Development of Life History Strategies  

PubMed Central

The National Longitudinal Study of Adolescent Health data were used to test predictions from life history theory. We hypothesized that (1) in young adulthood an emerging life history strategy would exist as a common factor underlying many life history traits (e.g., health, relationship stability, economic success), (2) both environmental harshness and unpredictability would account for unique variance in expression of adolescent and young adult life history strategies, and (3) adolescent life history traits would predict young adult life history strategy. These predictions were supported. The current findings suggest that the environmental parameters of harshness and unpredictability have concurrent effects on life history development in adolescence, as well as longitudinal effects into young adulthood. In addition, life history traits appear to be stable across developmental time from adolescence into young adulthood.

Figueredo, Aurelio Jose; Ellis, Bruce J.

2010-01-01

33

Measuring anxious responses to predictable and unpredictable threat in children and adolescents  

PubMed Central

Research has highlighted the need for new methods to assess emotions in children on multiple levels in order to gain better insight into the complex processes of emotional development. The startle reflex is a unique translational tool that has been utilized to study physiological processes during fear and anxiety in rodents and in human subjects. However, it has been challenging to implement developmentally-appropriate startle experiments in children. This paper describes a procedure that uses predictable and unpredictable aversive events to distinguish between phasic fear and sustained anxiety in children and adolescents. We investigated anxious responses, as measured with the startle reflex, in youth (N = 36, mean age[range] = 12.63 [7–17]) across three conditions: no aversive events (N), predictable aversive events (P), and unpredictable aversive events (U). Short-duration cues were presented several times in each condition. Aversive events were signaled by the cues in P, but were presented randomly in U. Participants showed fear-potentiated startle to the threat cue in P. Startle responses were also elevated between cues in U compared to N, suggesting that unpredictable aversive events can evoke a sustained state of anxiety in youth. This latter effect was influenced by sex, being greater in girls compared to boys. These findings indicate the feasibility of this experimental induction of the startle reflex in response to predictable and unpredictable events in children and adolescents, enabling future research on inter-individual differences in fear and anxiety and their development in youth.

Schmitz, Anja; Merikangas, Kathleen; Swendsen, Haruka; Cui, Lihong; Heaton, Leanne; Grillon, Christian

2011-01-01

34

The behavior of Kevlar fibers under environmental-stress conditions  

NASA Astrophysics Data System (ADS)

There are a myriad of mechanisms by which polymers can degrade and fail. It is therefore important to understand the physical mechanics, chemistry, their interactions, and kinetics. This pursuit becomes more than just "academic" because these mechanisms might just change with service conditions (i.e. environment and loading). If one does not understand these processes from the molecular to macroscopic scale it would be exceedingly difficult to gain information from accelerated testing because the mechanisms just might change from one condition to another. The purpose of this study was to probe these processes on scales ranging from molecular to macroscopic in environmental stress conditions. This study reports the results of environmental-stress degradation of Kevlar 49 fibers. The environmental agent of focus was the ubiquitous air pollutant complex NOsb{x}. Other materials and environments were investigated to a lesser extent for purposes of comparison. Mechanical property (i.e., short-term strength, modulus, and creep lifetime) degradation was examined using single fiber, yarn, and epoxy coated yarn (composite) specimens under environmental-stress conditions. Optical and scanning electron microscopes were employed to examine and compare the appearance of fracture features resulting from the various testing conditions. Atomic force microscopy augmented these studies with detailed topographical mappings and measures of the fracture surface frictional and modulus properties. Molecular processes (i.e., chain scission and other mechanical-chemical reactions) were probed by measures of changes in viscosity average molecular weight and the infrared spectra. It was demonstrated that environmental-stress degradation effects do occur in the Kevlar-NOsb{x} gas system. Strength decay in environmentally exposed unloaded fibers was demonstrated and a synergistic response in creep reduced fiber lifetimes by three orders of magnitude at moderate loadings. That is to say, the combination of creep load and environment attack was greater than the sum of their individual contributions when measured separately. Microscopy showed a relatively unchanged taxonomy of fracture features over the range of environmental-stress testing conditions employed. Molecular scale probes failed to evidence occurrence of macroscopically homogeneous chain scission, but localized chain scission mechanisms could not be dismissed. The failure mechanism was dominated by fibrillation and plastic slippage on a morphological level. The mechanism of NOx enhanced degradation was postulated as a plasticizing effect in the interfibrillar lower molecular weight phase.

Perry, Mark Charles

35

Effects of delta9-tetrahydrocannabinol on reward and anxiety in rats exposed to chronic unpredictable stress.  

PubMed

Although cannabis derivatives produce clear subjective motivational responses in humans leading to drug-seeking behaviour, the reinforcing attributes of these subjective effects are difficult to define in experimental animals. The aim of this study was to examine how exposure to chronic unpredictable stress (CUS) will affect reward function and anxiety after acute administration of Delta(9)-tetrahydrocannabinol (Delta(9)-THC) in rats. Male rats were exposed to either 10 days of CUS or no stressor. Alterations in brain reward function were assessed with the intracranial self-stimulation (ICSS) paradigm, and anxiety responses were measured with the elevated plus maze. CUS did not affect baseline brain stimulation reward thresholds. Delta(9)-THC did not exhibit reinforcing actions in the ICSS paradigm neither in nonstressed nor in stressed animals. More importantly, in nonstressed animals, both the low and the high dose of Delta(9)-THC exerted anxiolytic-like effects. In stressed animals, however, only the high dose of THC induced an anxiolytic-like response, whereas the low dose induced anxiogenic effects. The present results provide clear evidence for an anxiolytic effect of Delta(9)-THC both in stressed and in nonstressed animals, and indicate that environmental conditions, such as stressful experiences, do not alter the behavioural effects of Delta( 9)-THC in the ICSS paradigm. PMID:19406854

Fokos, S; Panagis, G

2009-04-30

36

The Retrospective Family Unpredictability Scale: Reliability and Validity  

Microsoft Academic Search

Family unpredictability or inconsistency may be responsible, in part, for the detrimental outcomes associated with parental\\u000a divorce, parental alcoholism, and family poverty. We assessed behavior patterns and regulatory systems in one’s family of\\u000a origin for the purposes of developing the Retrospective Family Unpredictability Scale (Retro-FUS). In the first study (N = 416, 89% Caucasian, 59% female), confirmatory factor analysis indicated a six-factor

Lisa Thomson Ross; Jennifer A. McDuff

2008-01-01

37

Protection of chemolithoautotrophic bacteria exposed to simulated Mars environmental conditions  

NASA Astrophysics Data System (ADS)

Current surface conditions (strong oxidative atmosphere, UV radiation, low temperatures and xeric conditions) on Mars are considered extremely challenging for life. The question is whether there are any features on Mars that could exert a protective effect against the sterilizing conditions detected on its surface. Potential habitability in the subsurface would increase if the overlaying material played a protective role. With the aim of evaluating this possibility we studied the viability of two microorganisms under different conditions in a Mars simulation chamber. An acidophilic chemolithotroph isolated from Río Tinto belonging to the Acidithiobacillus genus and Deinococcus radiodurans, a radiation resistant microorganism, were exposed to simulated Mars conditions under the protection of a layer of ferric oxides and hydroxides, a Mars regolith analogue. Samples of these microorganisms were exposed to UV radiation in Mars atmospheric conditions at different time intervals under the protection of 2 and 5 mm layers of oxidized iron minerals. Viability was evaluated by inoculation on fresh media and characterization of their growth cultures. Here we report the survival capability of both bacteria to simulated Mars environmental conditions.

Gómez, Felipe; Mateo-Martí, Eva; Prieto-Ballesteros, Olga; Martín-Gago, Jose; Amils, Ricardo

2010-10-01

38

Overview of environmental and hydrogeologic conditions at Dillingham, Alaska  

USGS Publications Warehouse

The remote city of Dillingham is at the northern end of Bristol Bay in southwestern Alaska. The hydrology of the area is strongly affected by the mild maritime climate and local geologic conditions. Dillingham residents obtain drinking water from both deep and shallow aquifers composed of gravels and sands and separated by layers of clay underlying the community. Alternative sources of drinking water are limited to the development of new wells because surface-water sources are of inadequate quantity or quality or are located at too great a distance from the population. The Federal Aviation Administration owns or operates airway support facilities in Dillingham and wishes to consider the severity of contamination and the current environmental setting when they evaluate options for compliance with environmental regulations at their facilities. This report describes the climate. vegetation, geology, soils, ground-water and surface-water hydrology, and flood potential of the areas surrounding the Federal Aviation Administration facilities near Dillingham.

Palcsak, Betty B.; Dorava, Joseph M.

1994-01-01

39

Thermomechanical characterization of environmentally conditioned shape memory polymer using nanoindentation  

NASA Astrophysics Data System (ADS)

Shape memory polymers (SMPs) are an emerging class of active polymers that have dual-shape capability, and are therefore candidate materials for multifunctional reconfigurable structures (i.e., morphing structures). However, the SMPs have not been fully tested to work in relevant environments (variable activation temperature, fuel and water swell, UV radiation, etc.) required for Air Force missions. In this study, epoxy-based SMPs were conditioned separately in simulated service environments designed to be reflective of anticipated performance requirements, namely, (1) exposure to UV radiation for 125 cycles, (2) immersion in jet-oil at ambient temperature, (3) immersion in jet-oil at 49°C, and (4) immersion in water at 49°C. The novel high-temperature indentation method was used to evaluate the mechanical properties and shape recovery ability of the conditioned SMPs. Results show that environmentally conditioned SMPs exhibit higher moduli in comparison to an unconditioned one. During free recovery, the indentation impressions of all SMPs disappeared as temperature reached above Tg, indicating that the material's ability to regain shape remains relatively unchanged with conditioning.

Fulcher, J. T.; Lu, Y. C.; Tandon, G. P.; Foster, D. C.

2010-03-01

40

Optimal size of storage for recovery after unpredictable disturbances  

Microsoft Academic Search

Terrestrial plants often live in environments in which above-ground photosynthetic organs (production parts) are suddenly removed by unpredictable disturbances, such as fire, frost, desiccation, pathogen attack, breakage by wind and trampling, or herbivory by insects and mammals. We study the optimal growth schedule for a plant having a below-ground storage organ that is used for recovery (or regrowth) of photosynthetic

YOH Iwasa; TAKUYA Kubo

1997-01-01

41

Unpredictable and Uncontrollable Events: A New Perspective on Experimental Neurosis  

ERIC Educational Resources Information Center

|Recent work has shown that unpredictable and/or uncontrollable events can produce a variety of cognitive, affective, and somatic disturbances to the organism. These disturbances are compared to and found to be quite similar to the symptoms of the classic cases of experimental neurosis described by Pavlov, Gantt, Liddell, Masserman, and Wolpe.…

Kihlstrom, John F.; Mineka, Susan

1978-01-01

42

Somatosensory control of precision grip during unpredictable pulling loads  

Microsoft Academic Search

In the previous paper regarding the somatosensory control of the human precision grip, we concluded that the elicited automatic grip force adjustments are graded by the amplitude of the imposed loads when restraining an ‘active’ object subjected to unpredictable pulling forces (Johansson et al. 1992a). Using the same subjects and apparatus, the present study examines the capacity to respond to

Roland S. Johansson; Charlotte Häger; Ronald Riso

1992-01-01

43

Environmental factors affecting indole metabolism under anaerobic conditions.  

PubMed Central

The influence of physiological and environmental factors on the accumulation of oxindole during anaerobic indole metabolism was investigated by high-performance liquid chromatography. Under methanogenic conditions, indole was temporarily converted to oxindole in stoichiometric amounts in media inoculated with three freshwater sediments and an organic soil. In media inoculated with methanogenic sewage sludge, the modest amounts of oxindole detected at 35 degrees C reached higher concentrations and persisted longer when the incubation temperature was decreased from 35 to 15 degrees C. Also, decreasing the concentration of sewage sludge used as an inoculum from 50 to 1% caused an increase in the accumulation of oxindole from 10 to 75% of the indole added. Under denitrifying conditions, regardless of the concentration or source of the inoculum, oxindole appeared in trace amounts but did not accumulate during indole metabolism. In addition, denitrifying consortia which previously metabolized indole degraded oxindole with no lag period. Our data suggest that oxindole accumulation under methanogenic, but not under denitrifying conditions is caused by differences between relative rates of oxindole production and destruction.

Madsen, E L; Francis, A J; Bollag, J M

1988-01-01

44

The community conditioning hypothesis and its application to environmental toxicology  

SciTech Connect

In this paper the authors present the community conditions hypothesis, ecological communities retain information bout events in their history. This hypothesis, which was derived from the concept of nonequilibrium community ecology, was developed as a framework for understanding the persistence of dose-related responses in multispecies toxicity tests. The authors present data from three standardized aquatic microcosm (SAM) toxicity tests using the water-soluble fractions from turbine fuels (Jet-A, JP-4, and JP-8). In all three tests, the toxicants depressed the Daphnia populations for several weeks, which resulted in algal blooms in the dosed microcosms due to lower predation rates. These effects were short-lived, and by the second and third months of the experiments, the Daphnia populations appeared to have recovered. However, multivariate analysis of the data released dose/response differences that reappeared during the later part of the tests, often due to differences in other consumers (rotifers, ostracods, ciliates), or algae that are not normally consumed (filamentous green algae and bluegreen algae). The findings are consistent with ecological theories that describe communities as the unique production of their etiologies. The implications of this to environmental toxicology are that almost all environmental events leave lasting effects, whether or not they have observed them.

Matthews, R.A.; Landis, W.G.; Matthews, G.B. [Western Washington Univ. Bellingham, WA (United States)

1996-04-01

45

Effects of environmental conditions on latex degradation in aquatic systems.  

PubMed

Following use polymer materials may be released to the natural environment distributed to various environmental compartments and may undergo a variety of mechanical and chemical weathering processes. This study characterised the degradation of a latex polymer of different thicknesses under a range of environmental conditions in outdoor microcosms. Samples were immersed in either demineralised water, artificial freshwater and marine water media and exposed for a period of 200-250 days with exposure starting at different times of the year. Effects of pH, agitation and the exclusion of light on degradation were also studied. At the end of the exposure period, recovery of polymer material ? 1.6 ?m ranged from a low of 22.04% (± 16.35, for the freshwater treatment at pH5.5) to a high of 97.73% (± 0.38, for the exclusion of light treatment). The disappearance of the bulk material corresponded to an increase in nanoparticles and dissolved organic material in the test media. Modelled degradation kinetics were characterised by multi-phasic degradation patterns and the results indicated degradation rate is affected by light intensity and polymer thickness. Mass balance analysis indicates that losses of volatile materials to the air compartment may also be occurring. PMID:23384646

Lambert, Scott; Sinclair, Chris J; Bradley, Emma L; Boxall, Alistair B A

2013-02-04

46

K, U, and Th behavior in Martian environmental conditions  

NASA Astrophysics Data System (ADS)

The possibility of K, U, and Th content determination from orbit and in situ allows consideration of those elements as geochemical indicators in the planetary studies. In the case of Mars the unambiguous interpretations of such data in terms of igneous rocks are remarkably constrained by the widespread rock alteration and the existence of exogenic deposits. Besides, the terrestrial experience indicates that K, U, and Th contents could be used as indicators of environmental geochemical processes. Thus the determination of K, U, and Th contents in the Martian surface materials could provide the indirect data on the conditions of some exogenic geological processes. The speculations on the K, U, and Th behavior in the Martian environments show that aeolian and aqueous processes leads to the preferential accumulation of K, U, and Th in fine dust material. The separation of K, U, and Th on Mars is smaller in scale to that on Earth.

Zolotov, M. Yu.; Krot, T. V.; Moroz, L. V.

1993-03-01

47

Changes in phosphorus smoke chemistry with environmental conditions  

SciTech Connect

Physical and chemical characteristics of two phosphorus aerosols were measured under a limited number of environmental conditions. The exposures and measurements were performed in a wind tunnel under various humidities, wind speeds and, to a limited extent, aerosol ages. Temperature, another important environmental variable that may influence the chemical form of the aerosols, was not studied in this research program. Steady-state aerosols generated by combustion of red phosphorus/butyl rubber (RP/BR) and white phosphorus (WP) were suspended in a closed-loop wind tunnel to simulate the continuous-generation of these obscurants at Army field training sites. Measured aerosol characteristics were found to differ significantly from characteristics predicted by simple phosphoric acid models previously thought to represent the chemical form of the suspended particles. As many as 28 individual phosphorus species were detected in aerosol samples. The distribution of linear and cyclic phosphorus species in the sampled aerosol was observed to vary significantly for changes in both aerosol age (0 to 60 min) and relative humidity (<5% to 90%). Hydrolysis toward phosphate occurred as the aerosol aged, and the rate of change was slower for higher humidities. More high-order phosphorus species appeared to be formed during aerosol generation at low relative humidities than at high humidity, as revealed by measurements near the combustion zone. Steady-state aerosols showed decreasing conversion to phosphate with increasing humidity. The highly speciated aerosols hydrolyzed to phosphate in less than 18 hr after deposition onto dry surfaces. Other aerosol characteristics such as mass concentration, water and phosphorus content of the particles, and particle size distribution were also measured.

McFadden, K.M.; Ligotke, M.W.; Garland, T.R.; Van Voris, P.; Schirmer, R.E.

1985-09-01

48

Seed germination ecology of the summer annual Cyperus squarrosus in an unpredictable mudflat habitat  

NASA Astrophysics Data System (ADS)

The purpose of our study was to better understand seed germination ecology of the summer annual sedge Cyperus squarrosus, which grows in various habitats, including mudflats and shallow soil over limestone bedrock (rock outcrops), where timing of the period favorable for germination and completion of the life cycle is unpredictable. Over a 28.5-month period, temperature and light:dark requirements for germination were determined at monthly intervals for seeds collected from mudflats and buried under flooded and under nonflooded conditions at natural temperature regimes. Data on dormancy and germination were compared to those published for seeds collected from plants growing on rock outcrops. Under both flooded and nonflooded conditions, seeds from mudflats exhibited an annual conditional dormancy/nondormancy cycle, similar to those from rock outcrops buried under nonflooded conditions. Seeds from mudflats germinated to higher percentages at mid-summer temperatures (35/20 °C) in mid-summer than those from rock outcrops. On the other hand, seeds from rock outcrops germinated to higher percentages at March temperatures (15/6 °C) in March than those from mudflats. Thus, seeds could germinate on mudflats any time from April through September if dewatering occurred, and they could germinate on rock outcrops any time from March through June and in September if soil moisture was nonlimiting; in both habitats light would be required for germination. Since seeds on mudflats may be flooded for several consecutive years, mudflats are more unpredictable than rock outcrops. Ability of seeds from mudflats to germinate to high percentages in light at 35/20 °C throughout the summer and those from rock outcrops not to do so may be related to the greater unpredictability of the mudflat. Each year for 11 years, seeds germinated in mudflat soil samples kept in a nonheated greenhouse, reaching a total of 22526 ± 1401 (mean ± S.E.) seeds m -2; thus, the species has the potential to form a large long-lived persistent soil seed bank.

Baskin, Carol C.; Baskin, Jerry M.; Chester, Edward W.

2004-07-01

49

Age at menarche: the influence of environmental conditions  

NASA Astrophysics Data System (ADS)

Age at menarche was studied by the recollection method in two groups of Causasian Jewish high school girls, inhabitants of two towns in Israel, Safad and Elat. The two towns differ mainly in climatic conditions. The age at menarche was found to be significantly lower ( P<0.02) in the hot town of Elat than in the temperate town of Safad: 13.30±1.21 and 13.58±0.9 years, respectively (mean ±SD). A significant association was found between the age at menarche and the town in which the girls lived. Accordingly, in the hot town of Elat, the percentage of girls who had their first menstrual cycle by the age of 12 years and earlier, was more than double that of the girls in Safad (17.9% and 7.1%, respectively). It is concluded that the environmental temperature, with or without any possible interaction of humidity, is probably responsible for the tendency for an earlier onset of menarche in girls living in the hot town of Elat.

Saar, E.; Shalev, C.; Dalal, I.; Sod-Moriah, U. A.

1988-03-01

50

Environmental and Geometrical Conditions to Sustain Crevice Corrosion in Alloy 22.  

National Technical Information Service (NTIS)

Alloy 22 (N06022) is highly resistant to localized corrosion. Under aggressive environmental conditions Alloy 22 may be susceptible to crevice corrosion in hot chloride (Cl-) solutions. The objective of the present work was to explore the environmental an...

R. M. Carranza M. A. Rodriguez R. B. Rebak

2006-01-01

51

OVERALL MASS TRANSFER COEFFICIENT FOR POLLUTANT EMISSIONS FROM SMALL WATER POOLS UNDER SIMULATED INDOOR ENVIRONMENTAL CONDITIONS  

EPA Science Inventory

Small chamber tests were conducted to experimentally determine the overall mass transfer coefficient for pollutant emissions from still water under simulated indoor-residential or occupational-environmental conditions. Fourteen tests were conducted in small environmental chambers...

52

Effects of simulated environmental conditions on glucocorticoid metabolite measurements in white-tailed deer feces  

Microsoft Academic Search

Environmental conditions may influence fecal glucocorticoid metabolite measurements if feces cannot be collected immediately after deposition. To evaluate the influence of environmental conditions on fecal glucocorticoid metabolite concentrations, we exposed fresh fecal samples to 1 of 5 simulated conditions: (1) room temperature (22°C), (2) high heat (38°C), (3) alternating high heat and room temperature cycle, (4) alternating freezing (?20°C) and

Brian E Washburn; Joshua J Millspaugh

2002-01-01

53

International Intercomparison of Environmental Dosimeters under Field and Laboratory Conditions.  

National Technical Information Service (NTIS)

Based on the results of a pilot study at ORNL in 1973, a more comprehensive international intercomparison of integrating dosimeters for the assessment of external penetrating environmental radiation fields was carried out. Forty-one laboratories from elev...

T. F. Gesell G. de Planque Burke K. Becker

1975-01-01

54

Adoption of Pest Management Strategies Under Varying Environmental Conditions.  

National Technical Information Service (NTIS)

The report analyzes several policy instruments designed to induce adoption of chemical-reducing pest management strategies. A model of technology choice is developed that shows how pest losses depend on environmental and resource characteristics as well a...

M. F. Caswell R. A. Shoemaker

1993-01-01

55

Assessing fear and anxiety in humans using the threat of predictable and unpredictable aversive events (the NPU-threat test)  

PubMed Central

The threat of predictable and unpredictable aversive events was developed to assess short-duration (fear) and long-duration (anxiety) aversive states in humans. A typical experiment consists of three conditions: a safe condition (neutral (N)), during which participants are safe from aversive stimuli, and two threat conditions—one in which aversive events are administered predictably (P) (i.e., signaled by a threat cue), and one in which aversive stimuli are administered unpredictably (U). During the so-called NPU -threat test, ongoing change in aversive states is measured with the startle reflex. The NPU -threat test has been validated in pharmacological and clinical studies and can be implemented in children and adults. Similar procedures have been applied in animal models, making the NPU -threat test an ideal tool for translational research. The procedure is relatively short (35 min), simple to implement and generates consistent results with large effect sizes.

Schmitz, Anja; Grillon, Christian

2012-01-01

56

Investigation of the Effect of Music and Noise on a Prolonged Intellectual Task with Environmental Conditioning.  

National Technical Information Service (NTIS)

The purpose of the research was to investigate the effect of music and noise on a prolonged intellectual task with environmental conditioning. A group of 46 subjects were administered algebra tests under nine treatment conditions consisting of two types o...

W. H. Nuckols

1969-01-01

57

Early growth conditions, phenotypic development and environmental change  

Microsoft Academic Search

Phenotypic development is the result of a complex interplay involving the organism's own genetic make-up and the environment it experiences during development. The latter encompasses not just the current environment, but also indirect, and sometimes lagged, components that result from environmental effects on its parents that are transmitted to their developing offspring in various ways and at various stages. These

Pat Monaghan

2007-01-01

58

Overview of environmental and hydrogeologic conditions at Saint Marys, Alaska  

USGS Publications Warehouse

The Federal Aviation Administration (FAA) owns or operates airway support facilities near Saint Marys along the Yukon River in west-central Alaska. The FAA is evaluating the severity of environmental contamination and options for remediation of environmental contamination at their facilities. Saint Marys is on a flood plain near the continence of the Yukon and Andreafsky Rivers and has long cold winters and short summers. Residents obtain their drinking water from an infiltration gallery fed by a creek near the village. Surface spills and disposal of hazardous materials combined with potential flooding may affect the quality of the surface and ground water. Alternative drinking-water sources are available, but would likely cost more than existing supplies to develop.

Nakanishi, Allan S.; Dorava, Joseph M.

1994-01-01

59

Effectiveness of Dry Eye Therapy Under Conditions of Environmental Stress  

PubMed Central

Purpose: Dry eye is often characterized by increased tear evaporation due to poor tear film quality, especially of the lipid component of the tear film. Using an environmental chamber to induce environmental stress, this study compared the effect of three lubricant eye drops on various aspects of tear physiology in a crossover design (evaporation was the principal outcome measure). Methods: Three eye drop formulas were tested: 0.5% carmellose sodium (Drop C), 0.5% carmellose sodium with added lipid (Drop C-L) and 1.0% glycerine with added lipid (Drop G-L). Nineteen control and 18?dry eye subjects used each product for 2 weeks, three times per day, in a random order, with a minimum 1-week washout between treatment periods. Tear evaporation, break up time, osmolarity, tear structure (by interferometry) and patient symptoms were assessed with the subjects adapted for 10?min in an environmental chamber controlled at 20% relative humidity and 22?°C. The treatment effects were analyzed using general linear model repeated measures analyses of variance. Results: In dry eye subjects, evaporation, break up time, osmolarity and symptoms improved for all formulas (p?environmental chamber in showing the difference in performance between dry eye treatments.

Madden, Louise C.; Simmons, Peter A.

2013-01-01

60

Common lung conditions: environmental pollutants and lung disease.  

PubMed

Exposure to environmental pollutants can have short- and long-term effects on lung health. Sources of air pollution include gases (eg, carbon monoxide, ozone) and particulate matter (eg, soot, dust). In the United States, the Environmental Protection Agency regulates air pollution. Elevated ozone concentrations are associated with increases in lung-related hospitalizations and mortality. Elevated particulate matter pollution increases the risk of cardiopulmonary and lung cancer mortality. Occupations with high exposures to pollutants (eg, heavy construction work, truck driving, auto mechanics) pose higher risk of chronic obstructive lung disease. Some industrial settings (eg, agriculture, sawmills, meat packing plants) also are associated with higher risks from pollutants. The Environmental Protection Agency issues an air quality index for cities and regions in the United States. The upper levels on the index are associated with increases in asthma-related emergency department visits and hospitalizations. Damp and moldy housing might make asthma symptoms worse; individuals from lower socioeconomic groups who live in lower quality housing are particularly at risk. Other household exposures that can have negative effects on lung health include radon, nanoparticles, and biomass fuels. PMID:23767420

Delzell, John E

2013-06-01

61

Silkwood vs. Kerr-McGee Corporation: unpredicted fallout  

SciTech Connect

The Silkwood suit is extolled as important precedent because it arguably gives states and private citizens acting as jurors the right to establish de facto nuclear regulatory policy. The Court's rationale in allowing punitive damages based on state tort law principles to be awarded against a private nuclear developer for injuries caused by the release of hazardous radioactive material from its plant is inconsistent with that used in a case involving Pacific Gas and Electric the year before. The author reviews the doctrine of preemption, discusses the legal and factural setting of the Silkwood case, and concludes that the Court could have provided a test similar to that invoked in labor law disputes to determine the available exceptions to total federal preemption of nuclear safety. Without such a test, the results of future litigation over nuclear safety concerns are unpredictable.

Silvestrini, L.V.F.

1985-01-01

62

Chaotic Stochasticity: A Ubiquitous Source of Unpredictability in Epidemics  

NASA Astrophysics Data System (ADS)

We address the question of whether or not childhood epidemics such as measles and chickenpox are chaotic, and argue that the best explanation of the observed unpredictability is that it is a manifestation of what we call chaotic stochasticity. Such chaos is driven and made permanent by the fluctuations from the mean field encountered in epidemics, or by extrinsic stochastic noise, and is dependent upon the existence of chaotic repellors in the mean field dynamics. Its existence is also a consequence of the near extinctions in the epidemic. For such systems, chaotic stochasticity is likely to be far more ubiquitous than the presence of deterministic chaotic attractors. It is likely to be a common phenomenon in biological dynamics.

Rand, D. A.; Wilson, H. B.

1991-11-01

63

Effects of Environmental Conditions on Isoprene Emission from Live Oak.  

National Technical Information Service (NTIS)

Live-oak plants (Quercus virginia) were subjected to various levels of CO2, water stress or photosynthetic photon flux density to test the hypothesis that isoprene biosynthesis occurred only under conditions of restricted CO2 availability. Isoprene emissi...

D. T. Tingey R. Evans M. Gumpertz

1981-01-01

64

Properties of Bacillus anthracis spores prepared under various environmental conditions  

Microsoft Academic Search

Bacillus anthracis makes highly stable, heat-resistant spores which remain viable for decades. Effect of various stress conditions on sporulation\\u000a in B. anthracis was studied in nutrient-deprived and sporulation medium adjusted to various pH and temperatures. The results revealed that\\u000a sporulation efficiency was dependent on conditions prevailing during sporulation. Sporulation occurred earlier in culture\\u000a sporulating at alkaline pH or in PBS

Renu B. Baweja; Mohd S. Zaman; Abid R. Mattoo; Kirti Sharma; Vishwas Tripathi; Anita Aggarwal; Gyanendra P. Dubey; Raj K. Kurupati; Munia Ganguli; N. K. Chaudhury; Somdutta Sen; Taposh K. Das; Wasudev N. Gade; Yogendra Singh

2008-01-01

65

Enhanced biodegradation of methoxychlor in soil under sequential environmental conditions.  

PubMed Central

Ring-U-[14C]methoxychlor [1,1-bis(p-methoxyphenyl)-2,2,2-trichloroethane] was incubated in soil under aerobic and anaerobic conditions. Primary degradation of methoxychlor occurred under anaerobic conditions, but not under aerobic conditions, after 3 months of incubation. Analysis of soil extracts, using gas chromatography, demonstrated that only 10% of the compound remained at initial concentrations of 10 and 100 ppm (wt/wt) of methoxychlor. Evidence is presented that a dechlorination reaction was responsible for primary degradation of methoxychlor. Analysis of soils treated with 100 ppm of methoxychlor in the presence of 2% HgCl2 showed that 100% of the compound remained after 3 months, indicating that degradation in the unpoisoned flasks was biologically mediated. Methanogenic organisms, however, are probably not involved, as strong inhibition of methane production was observed in all soils treated with methoxychlor. During the 3-month incubation period, little or no evaluation of 14CO2 or 14CH4 occurred under either aerobic or anaerobic conditions. Cometabolic processes may be responsible for the extensive molecular changes which occurred with methoxychlor because the rate of its disappearance from soil was observed to level off after exhaustion of soil organic matter. After this incubation period, soils previously incubated under anaerobic conditions were converted to aerobic conditions. The rates of 14CO2 evolution from soils exposed to anaerobic and aerobic sequences of environments ranged from 10- to 70-fold greater than that observed for soils exposed solely to an aerobic environment.

Fogel, S; Lancione, R L; Sewall, A E

1982-01-01

66

Environmental conditions affect spatial genetic structures and dispersal patterns in a solitary rodent.  

PubMed

The study of the spatial distribution of relatives in a population under contrasted environmental conditions provides critical insights into the flexibility of dispersal behaviour and the role of environmental conditions in shaping population relatedness and social structure. Yet few studies have evaluated the effects of fluctuating environmental conditions on relatedness structure of solitary species in the wild. The aim of this study was to determine the impact of interannual variations in environmental conditions on the spatial distribution of relatives [spatial genetic structure (SGS)] and dispersal patterns of a wild population of eastern chipmunks (Tamias striatus), a solitary rodent of North America. Eastern chipmunks depend on the seed of masting trees for reproduction and survival. Here, we combined the analysis of the SGS of adults with direct estimates of juvenile dispersal distance during six contrasted years with different dispersal seasons, population sizes and seed production. We found that environmental conditions influences the dispersal distances of juveniles and that male juveniles dispersed farther than females. The extent of the SGS of adult females varied between years and matched the variation in environmental conditions. In contrast, the SGS of males did not vary between years. We also found a difference in SGS between males and females that was consistent with male-biased dispersal. This study suggests that both the dispersal behaviour and the relatedness structure in a population of a solitary species can be relatively labile and change according to environmental conditions. PMID:23017101

Messier, Gabrielle Dubuc; Garant, Dany; Bergeron, Patrick; Réale, Denis

2012-09-27

67

Overview of environmental and hydrogeologic conditions at Moses Point, Alaska  

USGS Publications Warehouse

The Federal Aviation Administration facility at Moses Point is located at the mouth of the Kwiniuk River on the Seward Peninsula in northwestern Alaska. This area has long cold winters and short summers which affect the hydrology of the area. The Federal Aviation Administration owns or operates airport support facilities at the Moses Point site and wishes to consider the subsistence lifestyles of area residents and the quality of the current environment when evaluating options for remediation of environmental contamination at their facilities. Currently no operating wells are in the area, but the vulnerability of the aquifer and other alternative water supplies are being evaluated because the Federal Aviation Administration has a potential liability for the storage and use of hazardous materials in the area.

Dorava, J. M.; Ayres, R. P.; Sisco, W. C.

1994-01-01

68

Overview of environmental and hydrogeologic conditions at Tanana, Alaska  

USGS Publications Warehouse

The remote Native village of Tanana along the Yukon River in west-central Alaska has long cold winters and short summers. The Federal Aviation Administration owns or operates airway support facilities near Tanana and wishes to consider the subsistence lifestyle of the residents and the quality of the current environment when evaluating the severity of environmental contamination at these facilities. Tanana is located on the flood plain of the Yukon River and obtains its drinking water from a shallow aquifer located in thick alluvium underlying the village. Surface spills and disposal of hazardous materials combined with annual flooding of the Yukon River may affect the quality of the ground water. Alternative drinking-water sources are available, but may cost more than existing supplies.

Nakanishi, Allan S.; Dorava, Joseph M.

1994-01-01

69

Overview of environmental and hydrogeologic conditions at Galena, Alaska  

USGS Publications Warehouse

The remote Native village of Galena along the Yukon River in west-central Alaska has long cold winters and short summers that affects the hydrology of the area. The Federal Aviation Administration owns or operates airport support facilities in Galena and wishes to consider the subsistence lifestyle of the residents and the quality of the current environment when evaluating options for remediation of environmental contamination at these facilities. Galena is located on the flood plain of the Yukon River and obtains its drinking water from a shallow aquifer located in the thick alluvium underlying the village. Surface spills and disposal of hazardous materials combined with annual flooding of the Yukon River may affect the quality of the ground water. Alternative drinking-water sources are available but at significantly greater cost than existing supplies.

Nakanishi, Allan S.; Dorava, Joseph M.

1994-01-01

70

Overview of environmental and hydrogeologic conditions at Fort Yukon, Alaska  

USGS Publications Warehouse

The village of Fort Yukon along the Yukon River in east-central Alaska has long cold winters and short summers. The Federal Aviation Administration operates and supports some airport facilities in Fort Yukon and is evaluating the severity of environmental contamination and options for remediation of such contamination at their facilites. Fort Yukon is located on the flood plain of the Yukon River and obtains its drinking water from a shallow aquifer located in the thick alluvium underlying the village. Surface spills and disposal of hazardous materials combined with annual flooding of the Yukon River may affect the quality of the ground water. Alternative drinking-water sources are available from local surface-water bodies or from presently unidentified confined aquifers.

Nakanishi, Allan S.; Dorava, Joseph M.

1994-01-01

71

Environmental conditioning in the control of macrophage thrombospondin-1 production  

PubMed Central

Thrombospondin-1 (TSP-1) is a multifunctional protein which is secreted into the extracellular matrix during inflammation, where it modulates numerous components of the immune infiltrate. Macrophages are a source of TSP-1, which they produce in response to TLR4 mediated signals. Their production of TSP-1 is regulated by environmental signals that establish a threshold for the level of protein secretion that can be induced by LPS stimulation. Th1 and Th2 cytokines raise this threshold which leads to less TSP-1 production, while signals that promote the generation of regulatory macrophages lower it. TSP-1 plays no direct role in the regulation of its own secretion. In vivo in uveitis, in the presence of TLR-4 ligands, TSP-1 is initially produced by recruited macrophages but this decreases in the presence of inflammatory cytokines. The adaptive immune system therefore plays a dominant role in regulating TSP-1 production in the target organ during acute inflammation.

Fordham, Jezrom B.; Hua, Jing; Morwood, Sarah R.; Schewitz-Bowers, Lauren P.; Copland, David A.; Dick, Andrew D.; Nicholson, Lindsay B.

2012-01-01

72

Environmental overview and hydrogeologic conditions at Aniak, Alaska  

USGS Publications Warehouse

The remote Native village of Aniak, on the flood plain of the Kuskokwim River in southwestern Alaska, has long cold winters and short summers that affect both the hydrology of the area and the lifestyle of the residents. Aniak obtains its drinking water from a shallow aquifer in the thick alluvium underlying the village. Surface spills and disposal of hazardous materials combined with annual flooding of the Kuskokwim River may affect the quality of the ground water. Alternative drinking water sources are available but at significantly greater cost than existing supplies. The Federal Aviation Administration (FAA) owns or operates airport support facilities in Aniak. The subsistence lifestyle of the villagers and the quality of the current environment must be taken into consideration when the FAA evaluates options for remediation of environmental contamination at these facilities. This report describes the ground- and surface-water hydrology, geology, climate, vegetation, soils, and flood potential of the areas surrounding the FAA sites.

Dorava, J. M.

1994-01-01

73

Coping with an unpredictable and stressful environment: the life history and metabolic response to variable food and host availability in a polyphagous tephritid fly.  

PubMed

The way energy resources are used under variable environmental conditions lies at the heart of our understanding of resource management and opportunism in many organisms. Here we sought to determine how a time-limited, synovigenic and polyphagous insect with a high reproductive-potential (Anastrephaludens), copes behaviourally and metabolically with environmental unpredictability represented by constant and variable regimes of host availability and variation in food quality. We hypothesized that an adaptive response to a windfall of nutritious food would be the rapid accumulation of energy metabolites (whole body lipids, glycogen and proteins) in the female. We also studied patterns of oogenesis as an indicator of egg-reabsorption under stressful environmental conditions. As predicted, patterns of energy metabolites were mainly driven by the quality and temporal pattern of food availability. In contrast, patterns of host availability had a lower impact upon metabolites. When given constant access to high quality nutrients, after an initial increase early in life, whole body lipids and glycogen were regulated downward to a steady-state level and somatic protein levels did not vary. In contrast, when food uncertainty was introduced, whole body lipid, glycogen and protein oscillated sharply with peaks associated with pulses of high-quality food. Production of eggs was highest when offered continuous access to hosts and high quality food. Importantly, females fully recovered their reproductive capacity when fruit became available following a period of host deprivation. With no evidence of egg resorption and high levels of egg dumping, it appears that egg dumping may favour the continuous production of eggs such that the female's reproductive tissues are ready to respond to rapid changes in the availability of hosts. Our results exemplify the capacity of insects to maximize reproduction under variable and stressful environmental conditions. PMID:21855550

Aluja, Martín; Birke, Andrea; Guillén, Larissa; Díaz-Fleischer, Francisco; Nestel, David

2011-08-09

74

Environmental conditions in high mountain lakes containing toxic benthic cyanobacteria  

Microsoft Academic Search

In glacial lakes on an alpine pasture in Switzerland, benthic cyanobacteria produced microcystin, a cyclic hepatotoxic heptapeptide.\\u000a The cyanobacteria formed dense mats on sediments and submerged stones. The mats consisted mainly of Oscillatoria limosa, Phormidium\\u000a konstantinosum (= Oscillatoria tenuis) and Tychonema granulatum (= Oscillatoria granulata). In order to characterize the ecological\\u000a conditions of these cyanobacteria, nutrient concentrations were determined, and

Konstanze Mez; Kurt Hanselmann; Hans Rudolf Preisig

1998-01-01

75

Bandwidth and unpredictability properties of semiconductor ring lasers with chaotic optical injection  

NASA Astrophysics Data System (ADS)

The bandwidth and unpredictability properties of chaotic semiconductor ring lasers (SRLs) are numerically investigated. The SRL is brought to chaotic behaviors by utilizing chaotic optical injection from a master laser with optical feedback. The bandwidth and unpredictability degree of chaotic signal are examined for parameter regions of injection strength and frequency detuning. The chaos unpredictability degree is evaluated quantitatively by permutation entropy (PE). It is shown that, chaos can be obtained in large parameter regions, and simultaneous enhancement of bandwidth and unpredictability degree could be achieved for proper injection parameters. Such results are important for carrying out chaos-based communications and fast random number generations (RNGs).

Li, Nianqiang; Pan, Wei; Xiang, Shuiying; Yan, Lianshan; Luo, Bin; Zou, Xihua; Zhang, Liyue

2013-12-01

76

Overview of environmental and hydrogeologic conditions at Barrow, Alaska  

USGS Publications Warehouse

To assist the Federal Aviation Administration (FAA) in evaluating the potential effects of environmental contamination at their facility in Barrow, Alaska, a general assessment was made of the hydrologic system is the vicinity of the installation. The City of Barrow is located approximately 16 kilometers southwest of Point Barrow, the northernmost point in Alaska, and therefore lies within the region of continuous permafrost. Migration of surface or shallow- subsurface chemical releases in this environ- ment would be largely restricted by near-surface permafrost to surface water and the upper, suprapermafrost zone of the subsurface. In the arctic climate and tundra terrain of the Barrow area, this shallow environment has a limited capacity to attenuate the effects of either physical disturbances or chemical contamination and is therefore highly susceptible to degradation. Esatkuat Lagoon, the present drink- ing water supply for the City of Barrow, is located approximately 2 kilometers from the FAA facility. This lagoon is the only practical source of drinking water available to the City of Barrow because alternative sources of water in the area are (1) frozen throughout most of the year, (2) insufficient in volume, (3) of poor quality, or (4) too costly to develop and distribute.

McCarthy, K. A.

1994-01-01

77

Using a Physical Education Environmental Survey to Identify Areas of Concern and Improve Conditions  

ERIC Educational Resources Information Center

School environmental conditions can impact learning in physical educational classes. It is important for schools to control environmental health hazards, not only to promote a conducive school learning environment, but to also reduce associated health risks. To help physical education leaders determine the quality of physical education facilities…

Hill, Grant; Hulbert, George

2007-01-01

78

Civic Responsibility and the Environment: Linking Local Conditions to Community Environmental Activeness  

Microsoft Academic Search

In this article, we examine the extent to which variations in local social, economic, and spatial conditions might account for variation in community environmental activeness across 208 communities falling within nonmetropolitan areas in Mississippi. We use GIS technology to identify community boundaries, and use key informant and census data to measure community attributes. The findings indicate that community environmental activeness

DOMENICO PARISI; MICHAEL TAQUINO; STEVEN MICHAEL GRICE; DUANE A. GILL

2004-01-01

79

Using a Physical Education Environmental Survey to Identify Areas of Concern and Improve Conditions  

ERIC Educational Resources Information Center

|School environmental conditions can impact learning in physical educational classes. It is important for schools to control environmental health hazards, not only to promote a conducive school learning environment, but to also reduce associated health risks. To help physical education leaders determine the quality of physical education facilities…

Hill, Grant; Hulbert, George

2007-01-01

80

Multivariable environmental conditions promote photosynthetic adaptation potential in Arabidopsis thaliana.  

PubMed

Most of our knowledge on the regulation of photosynthesis originates from studies performed in highly controlled laboratory conditions. However, in their natural habitats plants are simultaneously subjected to a broad range of abiotic and biotic stimuli which influence photosynthetic efficiency; hence there is an emerging need to examine the process of photosynthesis under multivariable field conditions in order to elucidate the mechanisms that underlie its regulation. Such knowledge has potential for providing novel targets that would improve both crop yield and performance. In the present study we compared laboratory- and field-grown Arabidopsis thaliana plants in terms of photosynthetic efficiency in modulated light intensities and CO2 concentrations. We show here that the field-acclimated plants display highly efficient photosynthesis and are more tolerant to variable light intensities and CO2 concentrations than their laboratory-grown counterparts. We also demonstrate that some structural rearrangements of LHCII and PSII, together with altered pigments composition and stomatal density, are responsible for the differences in assimilation and photochemistry. Furthermore, we employ a transcript profiling approach to explain the genetic mechanisms underlying these adaptations and suggest that they are mainly induced by the high and fluctuating light intensities which occur in the natural environment. PMID:23287000

Wituszy?ska, Weronika; Ga??zka, Kamila; Rusaczonek, Anna; Vanderauwera, Sandy; Van Breusegem, Frank; Karpi?ski, Stanis?aw

2013-01-01

81

ENVIRONMENTALLY FRIENDLIER ORGANIC TRANSFORMATIONS ON MINERAL SUPPORTS UNDER NON-TRADITIONAL CONDITIONS  

EPA Science Inventory

Synthetic organic reactions performed under non-traditional conditions are gaining popularity primarily to circumvent the growing environmental concerns. A solvent-free approach that involves microwave (MW) exposure of neat reactants (undiluted) either in presence of a catalyst o...

82

76 FR 22161 - Fifty Seventh Meeting: RTCA Special Committee 135, Environmental Conditions and Test Procedures...  

Federal Register 2010, 2011, 2012, 2013

...Approval of Summary from Fifty-Sixth Meeting (RTCA Paper No. 224-110/SC 135-683). Review Approved Revised SC135 TOR (Terms of Reference)-- Environmental Conditions and Test Procedures for Airborne Equipment-- (RTCA Paper No....

2011-04-20

83

76 FR 59481 - Fifty Eighth Meeting: RTCA Special Committee 135, Environmental Conditions and Test Procedures...  

Federal Register 2010, 2011, 2012, 2013

...Approval of Summary from Fifty-Seventh Meeting (RTCA Paper No. 166-11/SC 135-685). Review Approved Revised SC135 TOR (Terms of Reference)-- Environmental Conditions and Test Procedures for Airborne Equipment-- (RTCA Paper No....

2011-09-26

84

ENVIRONMENTAL INFLUENCES ON THE RELEASE OF OPHIOSPHAERELLA AGROSTIS ASCOSPORES UNDER CONTROLLED AND FIELD CONDITIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ophiosphaerella agrostis, the causal agent of dead spot of creeping bentgrass (Agrostis stolonifera), can produce prodigious numbers of pseudothecia and ascospores throughout the summer. The environmental conditions and seasonal timings associated with O. agrostis ascospore release are unknown. The...

85

Estimating environmental conditions of carbonate crystal fan formation  

NASA Astrophysics Data System (ADS)

The sedimentary record reveals that the large-scale aspects of carbonate deposition have remained unchanged over > 3.4 Ga of Earth History. This reflects long term commonalities in the sources of DIC and alkalinity to seawater and the processes that generate and fill accommodation in sedimentary basins. Despite this stability, the record also reveals important first order changes in the nature of carbonate precipitation through time; this is documented in the decreasing abundance of sea floor carbonate precipitation. For example, carbonate crystal fans (large bladed crystals formed at the sediment-water interface, thought to be originally composed of aragonite) have a distinct distribution in time. They are common on Archean and Paleoproterozoic carbonate platforms and become rare by Neoproterozoic time, only reappearing during several unusual intervals (e.g. P-T mass extinction) in Phanerozoic basins. This has been interpreted as evidence for a decline in carbonate saturation through time. This pattern of distribution presents a fundamental problem. Despite being bathed in waters that are strongly supersaturated, direct precipitation of carbonate-bearing minerals on the sea floor is exceedingly rare in modern shallow tropical ocean basins. In order to examine this problem we examined processes controlling both the chemistry and physics of the sediment-water interface that could promote precipitation. Using a mathematical model to depict the influence of organic delivery and different microbial respiratory metabolisms on the carbonate chemistry within the shallow sediments, two non-unique chemical conditions emerge that indicate precipitation can be thermodynamically favorable on the seafloor from seawater with similar chemistry to today’s oceans. In agreement with modern porewater data, our results suggest that an important component inhibiting seafloor cementation is aerobic respiration in the shallow sediments. In addition to the chemical conditions of the interface, physical processes including high sedimentation rate, burrowing and seafloor agitation have the possibility of disrupting precipitation. We test hypotheses arising from our model results using geological observations of successions bearing crystal fans from the middle Ediacaran Rainstorm Member of the Johnnie Formation, Basin and Range, USA, and the Late Paleoproterozoic Rifle Formation, NW Territories Canada. By examining the accessory sediments associated with the cements from two specific examples from the record, quiescent periods with low background sedimentation rates emerge as important catalysts for growth. The accessory sediments associated with both examples are distinct from the surrounding sediments suggesting favorable conditions were not ever-present. Our analysis also shows that it is unlikely that all crystal fans result from a unique set of circumstances, rather there are several possible geobiological mechanisms that led to their deposition.

Bergmann, K. D.; Fischer, W. W.

2010-12-01

86

EVALUATION OF WASTE PACKAGE EXTERNAL ENVIRONMENTAL CONDITION STUDY  

SciTech Connect

The U. S. Department of Energy (DOE) is studying Yucca Mountain as the possible site for a permanent underground repository for disposal of spent nuclear fuel (SNF) and other high-level waste (HLW). The emplacement of high-level radioactive waste in Yucca Mountain will release a large amount of heat into the rock above and below the repository. Due to this heat, the rock temperature will rise, and then decrease when the production of decay heat falls below the rate at which heat escapes from the hot zone. In addition to raising the rock temperature, the heat will vaporize water, which will condense in cooler regions. The condensate water may drain back toward the emplacement drifts or it may ''shed'' through the pillars between emplacement drifts. Other effects, such as coupled chemical and mechanical processes, may influence the movement of water above, within, and below the emplacement drifts. This study examined near field environmental parameters that could have an effect on the waste package, including temperature, humidity, seepage rate, pH of seepage, chemistry (dissolved salts/minerals) of seepage, composition of drift atmosphere, colloids, and biota. This report is a Type I analysis performed in support of the development of System Description Documents (SDDs). A Type I analysis is a quantitative or qualitative analysis that may fulfill any of a variety of purposes associated with the Monitored Geologic Repository (MGR), other than providing direct analytical support for design output documents. A Type I analysis may establish design input, as defined in the ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998). This study establishes a technical basis for emplacement drift (i.e. at the waste package surface) environment criteria to be considered in the development of the waste package design. The information will support development of several SDDs and resolve emplacement drift external environment questions in the criteria of those documents. This study supports the following System Description Documents (SDDs): Uncanistered SNF Disposal Container, Canistered SNF Disposal Container, DHLW Disposal Container, DOE Waste Forms Disposal Container, Non-Fuel Components Disposal Container, Naval SNF Disposal Container and Ex-Container Systems development. Minimum and maximum bounding values for the parameters described in the scope of this study are established to support environment criteria development for those systems.

E. N. Lindner and E. F. Dembowski

1998-07-23

87

Long-term changes in cognitive bias and coping response as a result of chronic unpredictable stress during adolescence  

PubMed Central

Animals that experience adverse events in early life often have life-long changes to their physiology and behavior. Long-term effects of stress during early life have been studied extensively, but less attention has been given to the consequences of negative experiences solely during the adolescent phase. Adolescence is a particularly sensitive period of life when regulation of the glucocorticoid “stress” hormone response matures and specific regions in the brain undergo considerable change. Aversive experiences during this time might, therefore, be expected to generate long-term consequences for the adult phenotype. Here we investigated the long-term effects of exposure to chronic unpredictable stress during adolescence on adult decision-making, coping response, cognitive bias, and exploratory behavior in rats. Rats exposed to chronic unpredictable stress (e.g., isolation, crowding, cage tilt) were compared to control animals that were maintained in standard, predictable conditions throughout development. Unpredictable stress during adolescence resulted in a suite of long-term behavioral and cognitive changes including a negative cognitive bias [F(1, 12) = 5.000, P < 0.05], altered coping response [T(1, 14) = 2.216, P = 0.04], and accelerated decision-making [T(1, 14) = 3.245, P = 0.01]. Exposure to chronic stress during adolescence also caused a short-term increase in boldness behaviors; in a novel object test 15 days after the last stressor, animals exposed to chronic unpredictable stress had decreased latencies to leave a familiar shelter and approach a novel object [T(1, 14) = 2.240, P = 0.04; T(1, 14) = 2.419, P = 0.03, respectively]. The results showed that stress during adolescence has long-term impacts on behavior and cognition that affect the interpretation of ambiguous stimuli, behavioral response to adverse events, and how animals make decisions.

Chaby, Lauren E.; Cavigelli, Sonia A.; White, Amanda; Wang, Kayllie; Braithwaite, Victoria A.

2013-01-01

88

Wada basins and qualitative unpredictability in ecological models: a graphical interpretation  

Microsoft Academic Search

The capability of ecological models to make precise predictions was questioned with the discovery of chaos. Here it is shown that an alternative form of unpredictability is associated with some nonlinear models. The notion of a Wada basin, in which three or more basins share complexly interdigitated boundaries, represents this new form of unpredictability. It signifies that a single point

John Vandermeer

2004-01-01

89

The effect of unpredicted visual feedback on activation in the secondary somatosensory cortex during movement execution  

PubMed Central

Background A mechanism that monitors the congruence between sensory inputs and motor outputs is necessary to control voluntary movement. The representation of limb position is constantly updated on the basis of somatosensory and visual information and efference copy from motor areas. However, the cortical mechanism underlying detection of limb position using somatosensory and visual information has not been elucidated. This study investigated the influence of visual feedback on information processing in somatosensory areas during movement execution using magnetoencephalography. We used an experimental condition in which the visual information was incongruent despite the motor execution and somatosensory feedback being congruent. Subjects performed self-paced bimanual movements of both thumbs, either symmetric or asymmetric, under normal visual and mirrored conditions. The mirror condition provided a visual feedback by showing a reflection of the subject’s right hand in place of the left hand. Therefore, in the Asymmetric task of the Mirror condition, subjects saw symmetric movements despite performing asymmetric movements. Results Activation in the primary somatosensory area (SI) revealed inhibition of neural activity and that in the secondary somatosensory area (SII) showed enhancement with voluntary movement. In addition, the SII contralateral to the side of stimulation was significantly enhanced in the Asymmetric task of the Mirror condition, which provided non-veridical visual feedback. Conclusions These results suggested that visual information influenced the neuronal activity concerning sensorimotor interaction in the SII during motor execution. The SII contributes to the detection of unpredicted visual feedback of movement execution.

2012-01-01

90

Effects of Environmental and Social Conditions on Homosexual Pairing in the Japanese Beetle (Popillia japonica Newman)  

Microsoft Academic Search

Homosexual pairing between males occurs under natural conditions in a wide variety of taxa, including many insect species, but few studies have investigated how environmental and social conditions affect same-sex pairing in insects. We investigated factors affecting homosexual pairing in male Japanese beetles (Popillia japonica Newman) in the field and in the laboratory. Specifically, we investigated how time of day,

Paul V. Switzer; Patrick S. Forsythe; Kara Escajeda; Kipp C. Kruse

2004-01-01

91

Fractography analysis and fatigue of thermoplastic composite laminates at different environmental conditions  

Microsoft Academic Search

This paper is concerned with the understanding of the relationship between fatigue resistance and environmental conditioning by the fractographic analysis of the fracture surfaces. It assesses the fracture mode of fatigue tested laminates, carried out at different temperatures: ?55°C, +20°C and +80°C, and under two moisture contents, dry and 75% of saturated condition. It is verified that temperature is the

L. A. L. Franco; M. L. A. Graça; F. S. Silva

2008-01-01

92

Regulation of free corticosterone and CBG capacity under different environmental conditions in altricial nestlings.  

PubMed

The concentration of circulating glucocorticoids is regulated in response to environmental and endogenous conditions. Total circulating corticosterone, the main glucocorticoid in birds, consists of a fraction which is bound to corticosterone-binding globulins (CBG) and a free fraction. There is increasing evidence that the environment modulates free corticosterone levels through varying the concentration of CBG, but experimental evidence is lacking. To test the hypothesis that the regulation of chronic stress in response to endogenous and environmental conditions involves variation in both corticosterone release and CBG capacity, we performed an experiment with barn owl (Tyto alba) nestlings in two different years with pronounced differences in environmental conditions and in nestlings experimentally fed ad libitum. In half of the individuals we implanted a corticosterone-releasing pellet to artificially increase corticosterone levels and in the other half we implanted a placebo pellet. We then repeatedly collected blood samples to measure the change in total and free corticosterone levels as well as CBG capacity. The increase in circulating total corticosterone after artificial corticosterone administration varied with environmental conditions and with the food regime of the nestlings. The highest total corticosterone levels were found in nestlings growing up in poor environmental conditions and the lowest in ad libitum fed nestlings. CBG was highest in the year with poor environmental conditions, so that, contrary to total corticosterone, free corticosterone levels were low under poor environmental conditions. When nestlings were fed ad libitum total corticosterone, CBG and free corticosterone did not increase when administering corticosterone. These results suggest that depending on the individual history an animal experienced during development the HPA-axis is regulated differently. PMID:19467233

Almasi, Bettina; Roulin, Alexandre; Jenni-Eiermann, Susanne; Breuner, Creagh W; Jenni, Lukas

2009-05-23

93

Sex-biased maternal investment in voles: importance of environmental conditions.  

PubMed Central

Adaptive bias in sex allocation is traditionally proposed to be related to the condition of mothers as well as to the unequal fitness values of produced sexes. A positive relationship between mother condition and investment into male offspring is often predicted. This relationship was also recently found to depend on environmental conditions. We studied these causalities experimentally using a design where winter food supply was manipulated in eight outdoor-enclosed populations of field voles Microtus agrestis. At the beginning of the breeding season in spring, food-supplemented mothers seemed to be in a similar condition, measured as body mass, head width, body condition index and parasite load (blood parasite Trypanosoma), to non-supplemented mothers. Food supplements affected neither the litter size, the reproductive effort of mothers, nor the litter sex ratios at birth. However, food supplementation significantly increased the birth size of male offspring and improved their condition, as indicated by reduced parasite loads (intestinal Eimeria). Interestingly, mothers in good body condition produced larger male offspring only when environmental conditions were improved by food supplements. Although the adaptiveness of variation in mammalian sex ratios is still questionable, our study indicates that mothers in good condition bias their investment towards male offspring, but only when environmental conditions are favourable.

Koskela, Esa; Huitu, Otso; Koivula, Minna; Korpimaki, Erkki; Mappes, Tapio

2004-01-01

94

GidA expression in Salmonella is modulated under certain environmental conditions.  

PubMed

Glucose-inhibited division (GidA) protein is widely distributed in nature, and is highly conserved among bacteria and eukarya. In our previous study, a gidA mutant was attenuated in both in vitro and in vivo models of Salmonella infection. Furthermore, deletion of gidA resulted in a marked reduction in the expression of many virulence genes and proteins, suggesting a role for GidA in the regulation of Salmonella virulence. In this study, the effect of different environmental conditions (glucose, EDTA, and pH 5) on GidA expression in Salmonella was examined. Transcriptional analysis using real-time RT-PCR and a ?-galactosidase assay, displayed no differences in gidA transcription and promoter activity in different environmental conditions. Conversely, semiquantitative Western blot analysis revealed a significant increase in the GidA expression in Salmonella when grown under different environmental conditions. Salmonella in vitro virulence assays showed an increased virulence potential in the environmental conditions correlating to the increase in GidA expression. Together, our data indicate that GidA expression is modulated under different environmental conditions which correlate to increased Salmonella in vitro virulence. PMID:23579313

Rehl, Jaclyn M; Shippy, Daniel C; Eakley, Nicholas M; Brevik, Megan D; Sand, Jordan M; Cook, Mark E; Fadl, Amin A

2013-04-12

95

Competition between microcystin- and non-microcystin-producing Planktothrix agardhii (cyanobacteria) strains under different environmental conditions.  

PubMed

The factors that control the production of microcystins (hepatotoxins) during cyanobacterial blooms, and the function of these metabolites remain largely unknown. In an attempt to provide answers to these questions, we compared the fitness of microcystin (MC)-producing and non-MC-producing Planktothrix agardhii strains under various experimental conditions. More specifically, we investigated the effects of temperature, light intensity and nitrate concentrations on several MC-producing and non-MC-producing strains in monoculture and competition experiments. In the monoculture experiments, no significant difference in cell growth rates was found for any of the environmental conditions tested. On the other hand, at the end of the competition experiments, we found that when the environmental conditions limited cell growth, MC-producing strains were clearly winning out over the non-MC-producing ones. This suggested that, under growth-limiting conditions, the benefits of producing MC outweigh the cost. Moreover, the reverse was found under non-growth-limiting conditions, suggesting that under environmental conditions that favour cyanobacterial growth, the cost of MC production must outweigh its benefits. These findings suggest that environmental factors may have an indirect effect on the MC production rate, and on the selection of MC-producing and non-MC-producing strains, via their direct impact on both the cell growth rate and the cell densities in the cultures. Several hypotheses have been advanced concerning the possible function of MCs, but none of them seems to be supported by our data. PMID:18759740

Briand, Enora; Yéprémian, Claude; Humbert, Jean-François; Quiblier, Catherine

2008-08-28

96

Environmental conditions modulate the switch among different states of the hydrophobin Vmh2 from Pleurotus ostreatus.  

PubMed

Fungal hydrophobins are amphipathic, highly surface-active, and self-assembling proteins. The class I hydrophobin Vmh2 from the basidiomycete fungus Pleurotus ostreatus seems to be the most hydrophobic hydrophobin characterized so far. Structural and functional properties of the protein as a function of the environmental conditions have been determined. At least three distinct phenomena can occur, being modulated by the environmental conditions: (1) when the pH increases or in the presence of Ca(2+) ions, an assembled state, ?-sheet rich, is formed; (2) when the solvent polarity increases, the protein shows an increased tendency to reach hydrophobic/hydrophilic interfaces, with no detectable conformational change; and (3) when a reversible conformational change and reversible aggregation occur at high temperature. Modulation of the Vmh2 conformational/aggregation features by changing the environmental conditions can be very useful in view of the potential protein applications. PMID:22292968

Longobardi, Sara; Picone, Delia; Ercole, Carmine; Spadaccini, Roberta; De Stefano, Luca; Rea, Ilaria; Giardina, Paola

2012-02-21

97

Application of Whole Genome Expression Analysis to Assess Bacterial Responses to Environmental Conditions  

NASA Astrophysics Data System (ADS)

Bacterial responses to environmental signals are multifactorial and are coupled to changes in gene expression. An understanding of bacterial responses to environmental conditions is possible using microarray expression analysis. In this study, the utility of microarrays for examining changes in gene expression in Escherichia coli under different environmental conditions was assessed. RNA was isolated, hybridized to Affymetrix E. coli Genome 2.0 chips and analyzed using Affymetrix GCOS and Genespring software. Major limiting factors were obtaining enough quality RNA (107-108 cells to get 10?g RNA)and accounting for differences in growth rates under different conditions. Stabilization of RNA prior to isolation and taking extreme precautions while handling RNA were crucial. In addition, use of this method in ecological studies is limited by availability and cost of commercial arrays; choice of primers for cDNA synthesis, reproducibility, complexity of results generated and need to validate findings. This method may be more widely applicable with the development of better approaches for RNA recovery from environmental samples and increased number of available strain-specific arrays. Diligent experimental design and verification of results with real-time PCR or northern blots is needed. Overall, there is a great potential for use of this technology to discover mechanisms underlying organisms' responses to environmental conditions.

Vukanti, R. V.; Mintz, E. M.; Leff, L. G.

2005-05-01

98

ENVIRONMENTAL CONDITIONS MODULATE NEUROTOXIC EFFECTS OF PSYCHOMOTOR STIMULANT DRUGS OF ABUSE  

PubMed Central

Psychomotor stimulants such as methamphetamine (METH), amphetamine, and 3,4-Metylenedioxymethamphetamine (MDMA or ecstasy) are potent addictive drugs. While it is known that their abuse could result in adverse health complications, including neurotoxicity, both the environmental conditions and activity states associated with their intake could strongly enhance drug toxicity, often resulting in life-threatening health complications. In this review we analyze results of animal experiments that suggest that even moderate increases in environmental temperatures and physiological activation, the conditions typical of human raves parties, dramatically potentiate brain hyperthermic effects of METH and MDMA. We demonstrate that METH also induces breakdown of the blood-brain barrier (BBB), acute glial activation, brain edema, and structural abnormalities of various subtypes of brain cells; these effects are also strongly enhanced when the drug is used at moderately warm environmental conditions. We consider the mechanisms underlying environmental modulation of acute drug neurotoxicity and focus on the role of brain temperature, a critical homeostatic parameter that could be affected by metabolism-enhancing drugs and environmental conditions and affect neural activity and functions.

Kiyatkin, Eugene A.; Sharma, Hari S.

2013-01-01

99

Environmental conditions modulate neurotoxic effects of psychomotor stimulant drugs of abuse.  

PubMed

Psychomotor stimulants such as methamphetamine (METH), amphetamine, and 3,4-metylenedioxymethamphetamine (MDMA or ecstasy) are potent addictive drugs. While it is known that their abuse could result in adverse health complications, including neurotoxicity, both the environmental conditions and activity states associated with their intake could strongly enhance drug toxicity, often resulting in life-threatening health complications. In this review, we analyze results of animal experiments that suggest that even moderate increases in environmental temperatures and physiological activation, the conditions typical of human raves parties, dramatically potentiate brain hyperthermic effects of METH and MDMA. We demonstrate that METH also induces breakdown of the blood-brain barrier, acute glial activation, brain edema, and structural abnormalities of various subtypes of brain cells; these effects are also strongly enhanced when the drug is used at moderately warm environmental conditions. We consider the mechanisms underlying environmental modulation of acute drug neurotoxicity and focus on the role of brain temperature, a critical homeostatic parameter that could be affected by metabolism-enhancing drugs and environmental conditions and affect neural activity and functions. PMID:22748829

Kiyatkin, Eugene A; Sharma, Hari Shanker

2012-01-01

100

The consequences of adolescent chronic unpredictable stress exposure on brain and behavior.  

PubMed

There is increasing evidence for adolescence as a time period vulnerable to environmental perturbations such as stress. What is unclear is the persistent nature of the effects of stress and how specific these effects are to the type of stressor. In this review, we describe the effects of chronic, unpredictable stress (CUS) exposure during adolescence on adult behavior and brain morphology and function in animal models. We provide evidence for adolescence as a critical window for the effects of physical CUS that persist into adulthood, with ramifications for morphological development, associated hippocampal-dependent tasks, and anxiety- and depressive-like behaviors. The results of this investigation are contrasted against those of social CUS stress exposure from the same time period that show reversible and, in the case of responses to drugs of abuse, potentially protective effects in adulthood. Finally, we discuss potential underlying mechanisms for these morphological and behavioral findings. It is our aim that the research highlighted in this review will aid in our understanding of the role of stress in adolescent mental health and development. This article is part of a Special Issue entitled: Stress, Emotional Behavior and the Endocannabinoid System. PMID:23000538

Hollis, F; Isgor, C; Kabbaj, M

2012-09-20

101

Changes in Environmental Conditions During Dreissena Colonization of a Monitoring Station in Eastern Lake Erie  

Microsoft Academic Search

Effects of colonization and subsequent population density increases of Dreissena have been monitored annually at a site in eastern Lake Erie near the Niagara River. Striking changes in environmental conditions coincided with build-up of the Dreissena population from 1989 to 1992. A peak mean population density of 320,000 individuals\\/m2 was observed in July 1991. Changes in conditions between 1988 and

E. Todd Howell; Christopher H. Marvin; Robert W. Bilyea; Peter B. Kauss; Keith Somers

1996-01-01

102

Solar Powered air conditioning as a solution to reduce environmental pollution in Tunisia  

Microsoft Academic Search

In Tunisia, during the summer, the demand for electricity greatly increases because of the extensive use of air-conditioning systems. This is a source of major problems in the country’s electricity supply and contributes to an increase of CO2 emissions causing the environmental pollution and global warming. On the other hand, vapor compression air conditioning systems have impacts on stratospheric ozone

Moncef Balghouthi; Mohamed Hachemi Chahbani; Amenallah Guizani

2005-01-01

103

A benthic index of environmental condition of Gulf of Mexico estuaries  

Microsoft Academic Search

An index was developed for estuarine macrobenthos in the Gulf of Mexico that discriminated between areas with degraded environmental\\u000a conditions and areas with undegraded or reference conditions. Test sites were identified as degraded or reference based on\\u000a criteria for dissolved oxygen levels, sediment toxicity tests, and sediment contamination. Discriminant analysis was used\\u000a to identify a suite of measures of benthic

Virginia D. Engle; J. Kevin Summers; Gary R. Gaston

1994-01-01

104

Environmental consequences of impact cratering events as a function of ambient conditions on Earth.  

PubMed

The end of the Mesozoic Era is defined by a dramatic floral and faunal turnover that has been linked with the Chicxulub impact event, thus leading to the realization that impact cratering can affect both the geologic and biologic evolution of Earth. However, the environmental consequences of an impact event and any subsequent biological effects rely on several factors, including the ambient environmental conditions and the extant ecosystem structures at the time of impact. Some of the severest environmental perturbations of the Chicxulub impact event would not have been significant in some periods of Earth history. Consequently, the environmental and biological effects of an impact event must be evaluated in the context in which it occurs. PMID:12809133

Kring, David A

2003-01-01

105

Variability in appetite of turbot, Scophthalmus maximus under intensive rearing conditions: the role of environmental factors  

Microsoft Academic Search

The aim of this investigation was to identify the environmental parameters responsible for variation in the food demand of turbot held under normal intensive farming conditions on a commercial fish farm (Société France Turbot, Noirmoutier Island, France). The study was carried out on turbot held in 4 turbot growing ponds, from 20 April to 2 October 1996 and fish was

R Mallekh; J. P Lagardère; M. L Bégout Anras; J. Y Lafaye

1998-01-01

106

Enhancing Environmental Appraisal Effectiveness: Towards an Understanding of Internal Context Conditions in Organisational Learning  

Microsoft Academic Search

Part of a wider comparative European research project on developing the learning potential of appraisal in spatial planning in the UK, Germany and Italy, this paper aims to explore whether context conditions can facilitate internal organisational reforms and changes, trigger appraisal effectiveness, and facilitate organisational learning. The discussion comprises a synthesis of the environmental appraisal and organisational learning literatures and

Paola Gazzola; Urmila Jha-Thakur; Sue Kidd; Deborah Peel; Thomas Fischer

2011-01-01

107

The influence of environmental conditions on aspects of the time budgests of breeding ospreys  

Microsoft Academic Search

Ospreys (Pandion haliaetus) were observed for 350 h in 1975 in southeastern Virginia. Other studies have demonstrated that weather can have an effect on aspects of osprey foraging behavior (e.g., frequency of diving), but for the environmental conditions observed in this study, weather and other variables did not appear to limit the ability of ospreys to feed their young.

Christopher H. Stinson

1978-01-01

108

40 CFR 86.161-00 - Air conditioning environmental test facility ambient requirements.  

Code of Federal Regulations, 2010 CFR

...environmental exhaust emission test cell size is width 20 feet...and height 10 feet. (2) Test cells with smaller size dimensions...shown that all of the ambient test condition performance requirements...heat load are: (A) Metal halide; (B) Quartz halogen...

2010-07-01

109

Assessment of environmental conditions of Nan-Shih stream in Taiwan  

Microsoft Academic Search

Restoration is a complex endeavor requiring the understanding of the degrading environment before applying any improvement measure. Environmental and ecological data in Nan-Shih stream were investigated in this study to assess its stream condition. Based on the data collected, the Index of Biotic Integrity (IBI index) which takes fish species as the major target, the Family-level Biotic Index (FBI) aquatic

Tung-Jer Hu; Hsiao-Wen Wang; Hong-Yuan Lee

2007-01-01

110

Regulation of free corticosterone and CBG capacity under different environmental conditions in altricial nestlings  

Microsoft Academic Search

The concentration of circulating glucocorticoids is regulated in response to environmental and endogenous conditions. Total circulating corticosterone, the main glucocorticoid in birds, consists of a fraction which is bound to corticosterone-binding globulins (CBG) and a free fraction. There is increasing evidence that the environment modulates free corticosterone levels through varying the concentration of CBG, but experimental evidence is lacking. To

Bettina Almasi; Alexandre Roulin; Susanne Jenni-Eiermann; Creagh W. Breuner; Lukas Jenni

2009-01-01

111

A correlational analysis of the effects of changing environmental conditions on the NR atomic hydrogen maser  

Microsoft Academic Search

An extensive statistical analysis has been undertaken to determine if a correlation exists between changes in an NR atomic hydrogen maser's frequency offset and changes in environmental conditions. Correlation analyses have been performed comparing barometric pressure, humidity, and temperature with maser frequency offset as a function of time for periods ranging from 5.5 to 17 days. Semipartial correlation coefficients as

Richard A. Dragonette; Joseph J. Suter

1992-01-01

112

Influence of environmental conditions on late-summer cyanobacterial abundance in Saginaw Bay, Lake Huron  

Microsoft Academic Search

The relationships among environmental conditions and phytoplankton assemblages were characterized during late summer (2003-2005) in Saginaw Bay, Lake Huron. Differences among sampling stations, arising primarily from spatial disparities in water-column optical properties and nutrient availability, were evident. Cyanobacteria and diatoms dominated phytoplankton assemblages, with the greatest total chlorophyll a concentrations occurring at the innermost portions of the Bay. Microcystis abundance

D. F. Millie; G. L. Fahnenstiel; J. Dyble; R. Pigg; R. Rediske; D. M. Klarer; R. W. Litaker; P. A. Tester

2008-01-01

113

Environmental Control System Installer/Servicer (Residential Air Conditioning Mechanic). V-TECS Guide.  

ERIC Educational Resources Information Center

|This guide provides job relevant tasks, performance objectives, performance guides, resources, learning activitites, evaluation standards, and achievement testing in the occupation of environmental control system installer/servicer (residential air conditioning mechanic). It is designed to be used with any chosen teaching method. The course…

Meyer, Calvin F.; Benson, Robert T.

114

Postfire environmental conditions influence the spatial pattern of regeneration for Pinus ponderosa  

Microsoft Academic Search

Regeneration of ponderosa pine after fire depends on the patterns of seed availability and the environmental conditions that define safe sites for seedling establishment. A transect approach was applied in 2002 to determine the spatial distribution of regeneration from unburned to burned areas within the landscape impacted by the Jasper Fire of 2000 in the Black Hills of South Dakota

V. H. Bonnet; A. W. Schoettle; W. D. Shepperd

2005-01-01

115

Influence of Environmental Conditions on Methanogenic Compositions in Anaerobic Biogas Reactors  

Microsoft Academic Search

The influence of environmental parameters on the diversity of methanogenic communities in 15 full-scale biogas plants operating under different conditions with either manure or sludge as feedstock was studied. Fluorescence in situ hybridization was used to identify dominant methanogenic members of the Archaea in the reactor samples; enriched and pure cultures were used to support the in situ identification. Dominance

Dimitar Karakashev; Damien J. Batstone; Irini Angelidaki

2005-01-01

116

Dietary CDP-Choline Supplementation Prevents Memory Impairment Caused by Impoverished Environmental Conditions in Rats  

ERIC Educational Resources Information Center

The authors previously showed that dietary cytidine (5')-diphosphocholine (CDP-choline) supplementation could protect against the development of memory deficits in aging rats. In the present study, younger rats exposed to impoverished environmental conditions and manifesting hippocampal-dependent memory impairments similar to those observed in the…

Teather, Lisa A.; Wurtman, Richard J.

2005-01-01

117

Effects of environmental conditions to which nails are exposed on DNA analysis of them  

Microsoft Academic Search

To investigate the feasibility of DNA analysis of nails taken from human remains after environmental exposure, we tested the quantity and quality of DNA that could be recovered from nails exposed to various conditions. We first investigated whether there is an inter- or intra-subject difference in the DNA content of nails using nails obtained from 333 volunteers. DNA content did

Akinori Nakanishi; Fumio Moriya; Yoshiaki Hashimoto

2003-01-01

118

Engineered nanomaterial transformation under oxidative environmental conditions: development of an in vitro biomimetic assay.  

PubMed

Once released into the environment, engineered nanomaterials may be transformed by microbially mediated redox processes altering their toxicity and fate. Little information currently exists on engineered nanomaterial transformation under environmentally relevant conditions. Here, we report the development of an in vitro biomimetic assay for investigation of nanomaterial transformation under simulated oxidative environmental conditions. The assay is based on the extracellular hydroquinone-driven Fenton's reaction used by lignolytic fungi. We demonstrate the utility of the assay using CdSe(core)/ZnS(shell) quantum dots (QDs) functionalized with poly(ethylene glycol). QD transformation was assessed by UV-visible spectroscopy, inductively coupled plasma-optical emission spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). QDs were readily degraded under simulated oxidative environmental conditions: the ZnS shell eroded and cadmium was released from the QD core. TEM, electron diffraction analysis, and EDX of transformed QDs revealed formation of amorphous Se aggregates. The biomimetic hydroquinone-driven Fenton's reaction degraded QDs to a larger extent than did H202 and classical Fenton's reagent (H2O2 + Fe2+). This assay provides a new method to characterize transformations of nanoscale materials expected to occur under oxidative environmental conditions. PMID:19350941

Metz, Kevin M; Mangham, Andrew N; Bierman, Matthew J; Jin, Song; Hamers, Robert J; Pedersen, Joel A

2009-03-01

119

Engineered nanomaterial transformation under oxidative environmental conditions: Development of an in vitro biomimetic assay  

PubMed Central

Once released into the environment, engineered nanomaterials may be transformed by microbially mediated redox processes altering their toxicity and fate. Little information currently exists on engineered nanomaterial transformation under environmentally relevant conditions. Here, we report the development of an in vitro biomimetic assay for investigation of nanomaterial transformation under simulated oxidative environmental conditions. The assay is based on the extracellular hydroquinone-driven Fenton’s reaction used by lignolytic fungi. We demonstrate the utility of the assay using CdSecore/ZnSshell quantum dots (QDs) functionalized with poly(ethylene glycol). QD transformation was assessed by UV-Visible spectroscopy, inductively-coupled plasma-optical emission spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), and energy dispersive x-ray spectroscopy (EDX). QDs were readily degraded under simulated oxidative environmental conditions: the ZnS shell eroded and cadmium was released from the QD core. TEM, electron diffraction analysis and EDX of transformed QDs revealed formation of amorphous Se aggregates. The biomimetic hydroquinone-driven Fenton’s reaction degraded QDs to a larger extent than did H2O2 and classical Fenton’s reagent (H2O2 + Fe2+). This assay provides a new method to characterize transformations of nanoscale materials expected to occur under oxidative environmental conditions.

Metz, Kevin M.; Mangham, Andrew N.; Bierman, Matthew J.; Jin, Song; Hamers, Robert J.; Pedersen, Joel A.

2013-01-01

120

Effect of Environmental Temperature on Conditioning in the New-born Poikilothermic Rat  

Microsoft Academic Search

IN the rat a period of poikilothermy exists for approximately the first seventeen days of life1-2. In this phase of the development action potentials and nerve conduction rate decrease with the lowering of the environmental temperature3. Temperature may change, therefore, the ability of the new-born rat to learn the conditioned leg withdrawal to a vibrotactile stimulus.

D. F. Caldwell; R. Brand; J. Werboff

1962-01-01

121

Examples of landscape indicators for assessing environmental conditions and problems in urban and suburban areas  

USGS Publications Warehouse

Geo-indicators can help to assess environmental conditions in city urban and suburban areas. Those indicators should be meaningful for understanding environmental changes. From examples of Spanish and American cities, geo-indicators for assessing environmental conditions and changes in urban and suburban areas are proposed. The paper explore two types of geo-indicators. The first type presents general information that can be used to indicate the presence of a broad array of geologic conditions, either favouring or limiting various kinds of uses of the land. The second type of geo-indicator is the one most commonly used, and as a group most easily understood; these are site and problem specific and they are generally used after a problem is identified. Among them, watershed processes, seismicity and physiographic diversity are explained in more detail. A second dimension that is considered when discussing geo-indicators is the issue of scale. Broad scale investigations, covering extensive areas are only efficient at cataloguing general conditions common to much of the area or some outstanding feature within the area. This type of information is best used for policy type decisions. Detailed scale investigations can provide information about local conditions, but are not efficient at cataloguing vast areas. Information gathered at the detailed level is necessary for project design and construction.

Martin-Duque, J. F.; Godfrey, A.; Diez, A.; Cleaves, E.; Pedraza, J.; Sanz, M. A.; Carrasco, R. M.; Bodoque, J.

2002-01-01

122

Assessment of the environmental conditions of the Sarno river basin (south Italy): a stream sediment approach.  

PubMed

The Sarno river basin covers an area of 500 km(2) collecting the waters of Solofrana and Cavaiola tributaries. Originally it manly represents a source of livelihood for inhabitants by fishing and transporting goods; currently, the Sarno river, still partially used for irrigation, is affected by an extreme environmental degradation as a result of uncontrolled outflow of industrial waste. Within the framework of a wider geochemical prospecting project aiming at characterizing the whole territory of the Campania region, 89 stream sediment samples with a sampling density of 1 sample per 5 km(2) were collected in the river basin and analyzed by means of inductively coupled plasma-mass spectrometry in order to assess the environmental conditions at a regional scale. A GIS-aided technique, based on both the actual distribution of potentially harmful elements and their regional background values, was used to generate the maps of the contamination factors and of the contamination degrees for As, Cd, Cr, Cu, Hg, Pb and Zn. Furthermore, a factor analysis was performed to assess the nature and the extent of contamination sources for the river sediments. Results showed that the Sarno river basin could be divided in two "environmental status" units: one, low contaminated, corresponding to the hilly and mountain areas, and the second, from moderately to very highly contaminated, corresponding to the economically developed areas of the valley floor characterized by a high population density. This work was developed within a project that aims to investigate the relationships between environmental pollution and human health by analyzing environmental media (stream sediments, water, soil and vegetation) together with human hair of resident population. In this context, the spatial correlation between the extremely compromised environmental conditions of developed areas and the incidence rate of liver cancer in the same area was also explored posing the need of a careful costs/benefits analysis to assess whether the deterioration of the environment, that could adversely affect the conditions of public health, is worth the economic development. PMID:23053925

Albanese, Stefano; Iavazzo, Pietro; Adamo, Paola; Lima, Annamaria; De Vivo, Benedetto

2012-09-28

123

A new insight into the contribution of environmental conditions to tropical cyclone activities  

NASA Astrophysics Data System (ADS)

The changes of tropical cyclone (TC) activities in response to influencing environmental conditions have been paid more and more attention to in recent years. The potential contributions of single and multivariate environmental variables to annual TC frequency and intensity from 1970 to 2009 are investigated in this study. Instead of using correlation coefficient that assumes a set of samples satisfying the normal distribution, a quantitative measurement is formulated based on the information theory. The results show that dynamic environmental variables play an important role in variations of TC activities over the western North Pacific, North Atlantic, and eastern Pacific. These dynamic factors include wind shear between 850 and 200 hPa and 850-hPa relative vorticity. However, the effects of thermal factors on TC activities are distinct over different basins. The thermal environmental variables only have significant contributions to TC frequency and intensity over the eastern Pacific as well as to TC frequency over the North Atlantic. It is found that the primary factors influencing TC activities are indeed not the same over different basins because of the differences in atmospheric conditions and their changes across different areas. The effects of dynamic variables should be considered more in the regions such as the western North Pacific where the thermal conditions are always satisfied.

Wang, Yuan; Song, Jinjie; Wu, Rongsheng

2013-06-01

124

Behavior of stressed and unstressed 304L specimens in tuff repository environmental conditions  

SciTech Connect

This paper presents preliminary results of an investigation of the behavior of candidate barrier material for high-level nuclear waste storage, Type 304L stainless steel, in tuff repository environmental conditions. Tuff is a densely welded, devitrified, igneous rock common to the proposed repository site at Yucca Mountain, Nevada. The results discussed include: irradiation corrosion tests, U-bend irradiation corrosion tests, slow strain rate tests, and bent beam stress corrosion tests. Results indicate that Type 304L stainless steel shows excellent resistance to general, localized, and stress corrosion under the environmental and microstructural conditions tested so far. The environmental test conditions are 50 to 100{sup 0}C J-13 well water (non-saline, near neutral pH, and oxic in nature) and saturated steam at 100{sup 0}C. Microstructural conditions include solution annealed and long furnace heat treatments to provoke a sensitized structure. However, this particular type of stainless steel may be susceptible to long-term, low-temperature sensitization because of the combination of expected time at elevated temperature and residual stress in the container after emplacement in the repository. Other grades of austenitic stainless steels are reported to be more resistant to low-temperature sensitization. Future work will therefore include more extensive testing of these grades. 15 references, 5 figures, 7 tables.

Juhas, M.C.; McCright, R.D.; Garrison, R.E.

1984-11-01

125

Environmental conditions associated with bat white-nose syndrome in the north-eastern United States  

USGS Publications Warehouse

2. By 2010, the fungus G. destructans was detected in new areas of North America far from the area it was first observed, as well as in eight European bat species in different countries, yet mortality was not observed in many of these new areas of North America or in any part of Europe. This could be because of the differences in the fungus, rates of disease progression and/or in life-history or physiological traits of the affected bat species between different regions. Infection of bats by G. destructans without associated mortality might also suggest that certain environmental conditions might have to co-occur with fungal infection to cause mortality. 3. We tested the environmental conditions hypothesis using Maxent to map and model landscape surface conditions associated with WNS mortality. This approach was unique in that we modelled possible requisite environmental conditions for disease mortality and not simply the presence of the causative agent. 4. The top predictors of WNS mortality were land use/land cover types, mean air temperature of wettest quarter, elevation, frequency of precipitation and annual temperature range. Model results suggest that WNS mortality is most likely to occur in landscapes that are higher in elevation and topographically heterogeneous, drier and colder during winter, and more seasonally variable than surrounding landscapes. 5. Synthesis and applications. This study mapped the most likely environmental surface conditions associated with bat mortality owing to WNS in the north-eastern United Sates; maps can be used for selection of priority monitoring sites. Our results provide a starting point from which to investigate and predict the potential spread and population impacts of this catastrophic emerging disease.

Flory, Abigail R.; Kumar, Sunil; Stohlgren, Thomas J.; Cryan, Paul M.

2012-01-01

126

Environmental conditions and transcriptional regulation in Escherichia coli: a physiological integrative approach.  

PubMed

Bacteria develop a number of devices for sensing, responding, and adapting to different environmental conditions. Understanding within a genomic perspective how the transcriptional machinery of bacteria is modulated, as a response for changing conditions, is a major challenge for biologists. Knowledge of which genes are turned on or turned off under specific conditions is essential for our understanding of cell behavior. In this study we describe how the information pertaining to gene expression and associated growth conditions (even with very little knowledge of the associated regulatory mechanisms) is gathered from the literature and incorporated into RegulonDB, a database on transcriptional regulation and operon organization in E. coli. The link between growth conditions, signal transduction, and transcriptional regulation is modeled in the database in a simple format that highlights biological relevant information. As far as we know, there is no other database that explicitly clarifies the effect of environmental conditions on gene transcription. We discuss how this knowledge constitutes a benchmark that will impact future research aimed at integration of regulatory responses in the cell; for instance, analysis of microarrays, predicting culture behavior in biotechnological processes, and comprehension of dynamics of regulatory networks. This integrated knowledge will contribute to the future goal of modeling the behavior of E. coli as an entire cell. The RegulonDB database can be accessed on the web at the URL: http://www.cifn.unam.mx/Computational_Biology/regulondb/. PMID:14708114

Martínez-Antonio, Agustino; Salgado, Heladia; Gama-Castro, Socorro; Gutiérrez-Ríos, Rosa María; Jiménez-Jacinto, Verónica; Collado-Vides, Julio

2003-12-30

127

[Comparative analysis of the physical status of students living under different conditions of environmental pollution].  

PubMed

The physical status was comparatively studied in students living under different conditions of environmental pollution. The anthropometric and some physiometric (vital capacity) parameters were established to be lower in students from polluted areas than in those from relatively pure ones. The students from polluted areas were observed to have higher hemodynamic parameters (heart rate, stroke volume, cardiac output). The results of the study improve and supplement knowledge of the physical development of the students living in the areas with varying environmental pollution levels and reflect the morphofunctional status that is an indicator in the evaluation of the body's functional tension, which may suggest the suppressing action of environmental pollution on the students' body. PMID:20873272

Musalimova, R S; Valiakhmetov, R M

128

Wada Basins and Unpredictability in Hamiltonian and Dissipative Systems  

NASA Astrophysics Data System (ADS)

Prediction is one of the fundamental goals of science. When prediction is lost, it can be thought that one of the foundations of science is shattered. The notion of a chaotic system and the sensitive dependence on initial conditions implies a certain lack of prediction on the time evolution along an orbit. However we do not speak here about this temporal prediction, but about an extreme dependence on the initial conditions that fractal structures in phase space impose, and that obstructs the prediction of the final state of the system.

Aguirre, Jacobo; Vallejo, Juan Carlos; Sanjuan, Miguel A. F.

129

Variability in oxidative degradation of charcoal: Influence of production conditions and environmental exposure  

NASA Astrophysics Data System (ADS)

Charcoal is a key component of the Black Carbon (BC) continuum, where BC is characterized as a recalcitrant, fire-derived, polyaromatic material. Charcoal is an important source of palaeoenvironmental data, and of great interest as a potential carbon sink, due to its high apparent environmental stability. However, at least some forms of charcoal are clearly susceptible to environmental alteration and degradation over relatively short timescales. Although these processes have importance for the role of charcoal in global biogeochemistry, they remain poorly understood. Here we present results of an investigation into the susceptibility of a range of charcoal samples to oxidative degradation in acidified potassium dichromate. The study examines both freshly-produced charcoal, and charcoal exposed to environmental conditions for up to 50,000 years. We compare the proportion of carbon present in different forms between the samples, specifically with respect to the relative chemical resistance of these forms. This was undertaken in order to improve understanding of the post-depositional diagenetic changes affecting charcoal within environmental deposits. A wide range in chemical compositions are apparent both within and between the sample groups. In freshly-produced charcoal, material produced at 300 °C contains carbon with more labile forms than charcoal produced at ?400 °C, signifying a key chemical change over the 300-400 °C temperature range. Charcoal exposed to environmental depositional conditions is frequently composed of a highly carboxylated aromatic structure and contains a range of carbon fractions of varying oxidative resistance. These findings suggest that a significant number of the environmental charcoals have undergone post-depositional diagenetic alteration. Further, the data highlight the potential for the use of controlled progressive oxidative degradation as a method to characterize chemical differences between individual charcoal samples.

Ascough, P. L.; Bird, M. I.; Francis, S. M.; Thornton, B.; Midwood, A. J.; Scott, A. C.; Apperley, D.

2011-05-01

130

Genetic, environmental and maternal effects on magpie nestling-fitness traits under different nutritional conditions: a new experimental approach  

Microsoft Academic Search

Rearing full siblings under different environmental conditions allows partitioning of the total phenotypic variance of a trait into its genetic and environmental components. This, in natural bird populations, is usually achieved by cross-fostering experimental designs. We estimated genetic and environmental components of nestling-fitness traits using an alternative experimental approach in a magpie (Pica pica) population. Two broods of full siblings

Liesbeth De Neve; Juan José Soler; Tomás Pérez-Contreras; Manuel Soler

131

Relating coral species traits to environmental conditions in the Jakarta Bay\\/Pulau Seribu reef system, Indonesia  

Microsoft Academic Search

A key question in ecology is how biological traits of species determine their locations within an ecosystem. Identifying associations between species traits and environmental variables can help us to understand the causes of disturbance and predict whether species with given traits will persist under changing environmental conditions. To this end corals and environmental variables were sampled in 20 patch reefs

P. G. Rachello-Dolmen; D. F. R. Cleary

2007-01-01

132

The hidden function of photosynthesis: a sensing system for environmental conditions that regulates plant acclimation responses.  

PubMed

Plants convert light energy from the sun into chemical energy by photosynthesis. Since they are sessile, they have to deal with a wide range of conditions in their immediate environment. Many abiotic and biotic parameters exhibit considerable fluctuations which can have detrimental effects especially on the efficiency of photosynthetic light harvesting. During evolution, plants, therefore, evolved a number of acclimation processes which help them to adapt photosynthesis to such environmental changes. This includes protective mechanisms such as excess energy dissipation and processes supporting energy redistribution, e.g. state transitions or photosystem stoichiometry adjustment. Intriguingly, all these responses are triggered by photosynthesis itself via the interplay of its light reaction and the Calvin-Benson cycle with the residing environmental condition. Thus, besides its primary function in harnessing and converting light energy, photosynthesis acts as a sensing system for environmental changes that controls molecular acclimation responses which adapt the photosynthetic function to the environmental change. Important signalling parameters directly or indirectly affected by the environment are the pH gradient across the thylakoid membrane and the redox states of components of the photosynthetic electron transport chain and/or electron end acceptors coupled to it. Recent advances demonstrate that these signals control post-translational modifications of the photosynthetic protein complexes and also affect plastid and nuclear gene expression machineries as well as metabolic pathways providing a regulatory framework for an integrated response of the plant to the environment at all cellular levels. PMID:22441589

Pfannschmidt, Thomas; Yang, Chunhong

2012-03-23

133

DURABILITY OF GFRP RODS, LAMINATES, AND SANDWICH PANELS SUBJECTED TO VARIOUS ENVIRONMENTAL CONDITIONING  

Microsoft Academic Search

This paper outlines the performance of glass fiber-reinforced polymeric (GFRP) materials subjected to various environmental conditioning. The study is performed in conjunction with the construction of one bridge using FRP-reinforced concrete panels and three bridges using GFRP sandwich panels. GFRP rods utilizing a urethane-modified vinyl ester resin and GFRP laminates and sandwich panels utilizing an isophthalic polyester resin were subjected

Danielle K. Stone; Daniel Koenigsfeld; John Myers; Antonio Nanni

134

Effect of Environmental Conditions on the Fluoride Sensitivity of Acid Production by S. sanguis NCTC 7865  

Microsoft Academic Search

Growth and environmental conditions affected the fluoride (F) sensitivity of acid production by Streptococcus sanguis NCTC 7865. Cells grown glucose-limited in a chemostat were generally more sensitive than those harvested from cultures in which there was an excess of glucose (amino acid-limited). There was no consistent relationship between the growth rate of cells and their F sensitivity. Slower-growing cells (mean

P. D. Marsh; A. S. McDermid; C. W. Keevil; D. C. Ellwood

1985-01-01

135

Influence of harsh environmental conditions on CFRP-aluminum single lap joints  

Microsoft Academic Search

Purpose – The objective of this paper is to investigate the influence of harsh environmental conditions on the fundamental failure mechanisms of carbon fiber reinforced plastic (CFRP)-aluminum single lap single-bolted joints under tensile loading. Design\\/methodology\\/approach – CFRP-aluminum single lap joints were aged under extremely hot (60°C), hot and humid (60°C, 95%RH), and freezing cold (?51°C) environments and tensile-tested to measure

Luis Breziner; Parsaoran Hutapea

2008-01-01

136

Inclusion of local environmental conditions alters high-latitude vegetation change predictions based on bioclimatic models  

Microsoft Academic Search

Current predictions of how species will respond to climate change are typically based on coarse-grained climate surfaces utilizing\\u000a bioclimate envelope modelling. However, the suitability of environmental conditions for a given species might result from\\u000a a variety of factors including some unrelated to climate. To address this issue, we investigated whether the inclusion of\\u000a topographical and soil information in bioclimatic envelope

Henna Sormunen; Risto Virtanen; Miska Luoto

2011-01-01

137

Behavior of stressed and unstressed 304L specimens in tuff repository environmental conditions  

Microsoft Academic Search

This paper presents preliminary results of an investigation of the behavior of candidate barrier material for high-level nuclear waste storage, Type 304L stainless steel, in tuff repository environmental conditions. Tuff is a densely welded, devitrified, igneous rock common to the proposed repository site at Yucca Mountain, Nevada. The results discussed include: irradiation corrosion tests, U-bend irradiation corrosion tests, slow strain

M. C. Juhas; R. D. McCright; R. E. Garrison

1984-01-01

138

Biodegradation of agro-industrial orange waste under solid state fermentation and natural environmental conditions  

Microsoft Academic Search

Evaluation of the possibility of the re-use of agro-industrial orange peel and pulp wastes under solid state fermentation and natural environmental condition as a source of enzymes production (? & ? amylase, cellulase, pectinase(s), lipase(s), esterase(s) and peroxidase(s)) the physiological enzymes of lysis and total protein. Different microorganisms such as fungi, bacteria and yeast which were charged of waste analyse

Shahera H. Attyia; Sanaa M. Ashour

139

Interactions of NADP-Reducing Enzymes Across Varying Environmental Conditions: A Model of Biological Complexity  

PubMed Central

Interactions across biological networks are often quantified under a single set of conditions; however, cellular behaviors are dynamic and interactions can be expected to change in response to molecular context and environment. To determine the consistency of network interactions, we examined the enzyme network responsible for the reduction of nicotinamide adenine dinucleotide phosphate (NADP) to NADPH across three different conditions: oxidative stress, starvation, and desiccation. Synthetic, activity-variant alleles were used in Drosophila melanogaster for glucose-6-phosphate dehydrogenase (G6pd), cytosolic isocitrate dehydrogenase (Idh), and cytosolic malic enzyme (Men) along with seven different genetic backgrounds to lend biological relevance to the data. The responses of the NADP-reducing enzymes and two downstream phenotypes (lipid and glycogen concentration) were compared between the control and stress conditions. In general, responses in NADP-reducing enzymes were greater under conditions of oxidative stress, likely due to an increased demand for NADPH. Interactions between the enzymes were altered by environmental stress in directions and magnitudes that are consistent with differential contributions of the different enzymes to the NADPH pool: the contributions of G6PD and IDH seem to be accentuated by oxidative stress, and MEN by starvation. Overall, we find that biological network interactions are strongly influenced by environmental conditions, underscoring the importance of examining networks as dynamic entities.

Rzezniczak, Teresa Z.; Merritt, Thomas J. S.

2012-01-01

140

A Cuvette Design for Measurement of Ethylene Production and Carbon Dioxide Exchange by Intact Shoots under Controlled Environmental Conditions 1  

PubMed Central

A cuvette is described for simultaneous measurement of ethylene production and CO2 fixation by intact shoots under controlled environmental conditions. This design overcomes potential problems associated with closed systems conventionally used for studies on ethylene production, allowing accurate determination of rates of ethylene production in plants exposed to different environmental conditions.

Bassi, Pawan K.; Spencer, Mary S.

1979-01-01

141

Digestible Lysine Requirements of Male Broilers From 14 to 28 Days of Age Subjected to Different Environmental Conditions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Dietary amino acid requirements are influenced by environmental conditions. Two experiments examined growth responses of Ross × Ross TP 16 male broilers fed diets varying in digestible (dig) Lys concentrations from 14 to 28 d of age under different environmental conditions. Experiment 1 was conduc...

142

Unpredictable elbow joint perturbation during reaching results in multijoint motor equivalence  

PubMed Central

Motor equivalence expresses the idea that movement components reorganize in the face of perturbations to preserve the value of important performance variables, such as the hand's position in reaching. A formal method is introduced to evaluate this concept quantitatively: changes in joint configuration due to unpredictable elbow perturbation lead to a smaller change in performance variables than expected given the magnitude of joint configuration change. This study investigated whether motor equivalence was present during the entire movement trajectory and how magnitude of motor equivalence was affected by constraints imposed by two different target types. Subjects pointed to spherical and cylindrical targets both with and without an elbow joint perturbation produced by a low- or high-stiffness elastic band. Subjects' view of their arm was blocked in the initial position, and the perturbation condition was randomized to avoid prediction of the perturbation or its magnitude. A modification of the uncontrolled manifold method variance analysis was used to investigate how changes in joint configuration on perturbed vs. nonperturbed trials (joint deviation vector) affected the hand's position or orientation. Evidence for motor equivalence induced by the perturbation was present from the reach onset and increased with the strength of the perturbation after 40% of the reach, becoming more prominent as the reach progressed. Hand orientation was stabilized more strongly by motor equivalent changes in joint configuration than was three-dimensional position regardless of the target condition. Results are consistent with a recent model of neural control that allows for flexible patterns of joint coordination while resisting joint configuration deviations in directions that affect salient performance variables. The observations also fit a general scheme of synergic control with referent configurations defined across different levels of the motor hierarchy.

Mattos, D. J. S.; Latash, M. L.; Park, E.; Kuhl, J.

2011-01-01

143

Response of mosquitofish (Gambusia affinis) populations to seasonally unpredictable perturbations  

SciTech Connect

Many questions remain unresolved about the linkages between life history attributes of fishes and the tactics that these organisms employ in response to environmental uncertainty. Such questions include (1). If a perturbation affects the entire ecosystem, what are the consequences for a given population of fish (2) What tactics can a fish employ to increase its chances of leaving offspring (3) Do fish respond differently to such perturbations depending on the season (4) How do these changes relate to the overall resilience of the population The research reported here was designed to address such questions. Mosquito fish (Gambusia affinis) populations in thirteen experimental ponds at Oak Ridge National Laboratory were sampled ten times between June 1988, and July 1989 in response to a series of chemical disturbances. During each sampling period the population size and total biomass of Gambusia in each pond was estimated using photographs and a length weight regression. Size-frequency histograms were used to examine seasonal and dose-related changes in population structure. Lipid content and reproductive allotment were measured for a series of fish from each pond on all dates to explore the energy allocation patterns at the individual. 106 refs., 38 figs., 16 tabs.

Horn, M.J.; Stewart, A.J.

1990-07-01

144

Chaos and unpredictability in evolutionary dynamics in discrete time.  

PubMed

A discrete-time version of the replicator equation for two-strategy games is studied. The stationary properties differ from those of continuous time for sufficiently large values of the parameters, where periodic and chaotic behavior replace the usual fixed-point population solutions. We observe the familiar period-doubling and chaotic-band-splitting attractor cascades of unimodal maps but in some cases more elaborate variations appear due to bimodality. Also unphysical stationary solutions can have unusual physical implications, such as the uncertainty of the final population caused by sensitivity to initial conditions and fractality of attractor preimage manifolds. PMID:21838406

Vilone, Daniele; Robledo, Alberto; Sánchez, Angel

2011-07-12

145

Unpredictable saccharin reinforcement enhances locomotor responding to amphetamine  

PubMed Central

Drug-naïve, non-deprived rats were trained to lever press for saccharin under fixed-ratio (FR) or variable-ratio (VR) schedules of reinforcement. Rats trained on the VR schedule in which saccharin reinforcement was not predicted by a fixed number of lever presses subsequently showed an enhanced locomotor response to a threshold amphetamine challenge injection (0.5 mg/kg IP) administered two weeks following the last saccharin session. This finding suggests that chronic exposure to gambling-like conditions of uncertain reinforcement can induce neuroadaptations in brain reward systems that are similar to those produced by repeated psychostimulant exposure and may lead to the development of addictive behaviors.

Singer, B. F.; Scott-Railton, J.; Vezina, P.

2011-01-01

146

Remodeling of Bacterial RNA Polymerase Supramolecular Complex in Response to Environmental Conditions  

SciTech Connect

Directed binding of RNA polymerase to distinct promoter elements controls transcription and promotes adaptive responses to changing environmental conditions. To identify proteins that modulate transcription, we have expressed a tagged alpha-subunit of RNA polymerase in Shewanella oneidensis under controlled growth conditions, isolated the protein complex using newly developed multiuse affinity probes, and used LC-MS/MS to identify proteins in the complex. Complementary fluorescence correlation spectroscopy measurements were used to determine the average size of the RNA polymerase complex in cellular lysates. We find that RNA polymerase exists as a large supramolecular complex with an apparent mass in excess of 1.4 MDa, whose protein composition substantially changes in response to growth conditions. Enzymes that copurify with RNA polymerase include those associated with tRNA processing, nucleotide metabolism, and energy biosynthesis, which we propose to be necessary for optimal transcriptional rates.

Verma, Seema; Xiong, Yijia; Mayer, M. Uljana; Squier, Thomas C.

2007-03-20

147

Coriander essential oil composition from two genotypes grown in different environmental conditions.  

PubMed

The objective was to study the essential oil composition of coriander fruits in plants growing in environments differing in soil conditions and weediness level. Factorial field experiments were conducted in two locations from the Rolling Pampas, Argentina, and two coriander landraces (European and Argentinean) were tested under two levels of nitrogen fertilization and weediness. Data were evaluated with uni- and multivariate techniques. The variation in the oil composition was related to the relative proportion of the constituents and not to the presence/absence of a particular component. Weather conditions in 1997 favored linalool and camphor in both landraces. Location, fertilization, and weediness also affected the chemical profile. The European landrace showed a more stable concentration of the major components than the Argentinean landrace. These results, which show the relationships between some environmental conditions and the essential oil composition, are useful in the development of innovative strategies aimed to improve oil composition and to manage crop pests. PMID:11982413

Gil, Alejandra; De La Fuente, Elba B; Lenardis, Adriana E; López Pereira, Mónica; Suárez, Susana A; Bandoni, Arnaldo; Van Baren, Catalina; Di Leo Lira, Paola; Ghersa, Claudio M

2002-05-01

148

Laboratory emissivity measurements of the plagioclase solid solution series under varying environmental conditions  

NASA Astrophysics Data System (ADS)

New laboratory thermal infrared emissivity measurements of the plagioclase solid solution series over the 1700 ˜ 400 cm-1 (6-25 ?m) spectral range are presented. Thermal infrared (TIR) spectral changes for fine-particulate samples (0-25 ?m) are characterized for the first time under different laboratory environmental conditions: ambient (terrestrial-like), half-vacuum (Mars-like), vacuum, and vacuum with cooled chamber (lunar-like). Under all environmental conditions the Christiansen Feature (CF) is observed to vary in a systematic way with Na-rich end-member (albite) having a CF position at the highest wave number (shortest wavelength) and the Ca-rich end-member (anorthite) having a CF position with the lowest wave number (longest wavelength). As pressure decreases to <10-3 mbar four observations are made: (1) the CF position shifts to higher wave numbers, (2) the spectral contrast of the CF increases relative to the RB, (3) the spectral contrast of the RB in the ˜1200-900 spectral range decreases while the spectral contrast of the RB in the ˜800-400 spectral range either increases or remains the same and (4) the TF disappears. A relationship between the wavelength position of the CF measured under simulated lunar conditions and plagioclase composition (An#) is developed. Although its exact form may evolve with additional data, this linear relationship should be applied to current and future TIR data sets of the Moon. Our new spectral measurements demonstrate how sensitive thermal infrared emissivity spectra of plagioclase feldspars are to the environmental conditions under which they are measured and provide important constraints for interpreting current and future thermal infrared data sets.

Donaldson Hanna, K. L.; Thomas, I. R.; Bowles, N. E.; Greenhagen, B. T.; Pieters, C. M.; Mustard, J. F.; Jackson, C. R. M.; Wyatt, M. B.

2012-11-01

149

The effect of environmentally relevant conditions on PVP stabilised gold nanoparticles.  

PubMed

Nanoparticles are a major product from the nanotechnology industry and have been shown to have a potentially large environmental exposure and hazard. In this study, sterically stabilised polyvinyl pyrrolidone (PVP) 7 nm gold nanoparticles (NPs) were produced and characterised as prepared by surface plasmon resonance (SPR), size and aggregation, morphology and surface charge. Changes in these properties with changes in environmentally relevant conditions (pH, ionic strength, Ca concentration and fulvic acid presence) were quantified. These sterically stabilised NPs showed no aggregation with changes in pH or inorganic ions, even under high (0.1 M) Ca concentrations. In addition, the presence of fulvic acid resulted in no observable changes in SPR, size, aggregation or surface chemistry, suggesting limited interaction between the PVP stabilised nanoparticles and fulvic acid. Due to the lack of aggregation and interaction, these NPs are expected to be highly mobile and potentially bioavailable in the environment. PMID:22967928

Hitchman, Adam; Smith, Gregory H Sambrook; Ju-Nam, Yon; Sterling, Mark; Lead, Jamie R

2012-09-08

150

Environmental conditions influence the plant functional diversity effect on potential denitrification.  

PubMed

Global biodiversity loss has prompted research on the relationship between species diversity and ecosystem functioning. Few studies have examined how plant diversity impacts belowground processes; even fewer have examined how varying resource levels can influence the effect of plant diversity on microbial activity. In a field experiment in a restored wetland, we examined the role of plant trait diversity (or functional diversity, (FD)) and its interactions with natural levels of variability of soil properties, on a microbial process, denitrification potential (DNP). We demonstrated that FD significantly affected microbial DNP through its interactions with soil conditions; increasing FD led to increased DNP but mainly at higher levels of soil resources. Our results suggest that the effect of species diversity on ecosystem functioning may depend on environmental factors such as resource availability. Future biodiversity experiments should examine how natural levels of environmental variability impact the importance of biodiversity to ecosystem functioning. PMID:21311768

Sutton-Grier, Ariana E; Wright, Justin P; McGill, Bonnie M; Richardson, Curtis

2011-02-02

151

Environmental Conditions Influence the Plant Functional Diversity Effect on Potential Denitrification  

PubMed Central

Global biodiversity loss has prompted research on the relationship between species diversity and ecosystem functioning. Few studies have examined how plant diversity impacts belowground processes; even fewer have examined how varying resource levels can influence the effect of plant diversity on microbial activity. In a field experiment in a restored wetland, we examined the role of plant trait diversity (or functional diversity, (FD)) and its interactions with natural levels of variability of soil properties, on a microbial process, denitrification potential (DNP). We demonstrated that FD significantly affected microbial DNP through its interactions with soil conditions; increasing FD led to increased DNP but mainly at higher levels of soil resources. Our results suggest that the effect of species diversity on ecosystem functioning may depend on environmental factors such as resource availability. Future biodiversity experiments should examine how natural levels of environmental variability impact the importance of biodiversity to ecosystem functioning.

Sutton-Grier, Ariana E.; Wright, Justin P.; McGill, Bonnie M.; Richardson, Curtis

2011-01-01

152

Interaction between host genotype and environmental conditions affects bacterial density in Wolbachia symbiosis.  

PubMed

Regulation of microbial population density is a necessity in stable symbiotic interactions. In Wolbachia symbiosis, both bacterial and host genotypes are involved in density regulation, but environmental factors may also affect bacterial population density. Here, we studied the interaction between three strains of Wolbachia in two divergent homozygous lines of the wasp Leptopilina heterotoma at two different temperatures. Wolbachia density varied between the two host genotypes at only one temperature. Moreover, at this temperature, reciprocal-cross F1 insects displayed identical Wolbachia densities, which were intermediate between the densities in the two parental lines. While these findings confirm that the host genotype plays an important role in Wolbachia density, they also highlight its interaction with environmental conditions, making possible the evolution of local adaptations for the regulation of Wolbachia density. PMID:17251124

Mouton, Laurence; Henri, Hélène; Charif, Delphine; Boulétreau, Michel; Vavre, Fabrice

2007-04-22

153

Copepod population in Vellar estuary, Parangipettai coast in relation to environmental conditions.  

PubMed

Distribution and abundance of copepods were studied in relation to environmental conditions at two different ecosystems viz: Neritic (Bay of Bengal) and estuarine (Vellar estuary) of Parangipettai coast from September, 1998 toAugust, 2000. Over the study period, total 85 species of copepods were reported. Among these, the calanoid copepods constituted the major component with 63.52% followed by cyclopoids (29.41%) and harpacticoids (7.05%). The copepods population density was found to be high (2, 53,000 org l(-1)) in estuarine water, while the species diversity was higher (5.47) in neritic water. The observed spatio-temporal variations in the population density and species diversity of copepods were more related to the environmental state of respective study area. PMID:23741792

Santhanam, P; Perumal, P; Ananth, S; Devi, A Shenbaga

2012-11-01

154

Effects of unpredictable stimulation on pain and nociception across the cardiac cycle.  

PubMed

Previous research has demonstrated that the nociceptive flexion reflex (NFR) and pain-related evoked potentials are reduced in amplitude when elicited during the middle of the cardiac cycle. Despite these findings, suggesting a baroreceptor mechanism of antinociception during systole, pain intensity ratings reported in these studies were not modulated across the cardiac cycle. This discrepancy between the neurophysiological correlates of pain and its subjective experience was the focus of the current study that used a mixed block design to assess the effects of natural arterial baroreceptor activity on both the NFR and pain intensity and unpleasantness reports. Specifically, electrocutaneous stimuli were randomly delivered to the sural nerve at one of five intensities (50% pain threshold, 75% pain threshold, pain threshold, midway between pain threshold and pain tolerance, pain tolerance) at five intervals (0, 150, 300, 450, and 600ms) after the R-wave of the electrocardiogram. Under painful stimulation, intensity and unpleasantness varied in a quadratic manner across the cardiac cycle; pain was highest at R+300ms and lowest at R+0 and R+600ms. Under non-painful stimulation, ratings declined linearly as the cycle progressed. Finally, nociceptive responses did not differ among the R-wave to stimulation intervals for both painful and non-painful intensities. The observed phasic modulation of pain may be explained by a central nervous system alarm/defence reaction triggered by the unpredictability of the potentially damaging stimulation. The absence of systolic attenuation of nociceptive responding is compatible with previous evidence that baroreceptor modulation of the NFR is abolished under conditions of heightened arousal. PMID:19766395

Martins, Amadeu Quelhas; Ring, Christopher; McIntyre, David; Edwards, Louisa; Martin, Una

2009-09-18

155

Environmental Influences on the Release of Ophiosphaerella agrostis Ascospores Under Controlled and Field Conditions.  

PubMed

ABSTRACT Ophiosphaerella agrostis, the causal agent of dead spot of creeping bentgrass (Agrostis stolonifera), can produce prodigious numbers of pseudothecia and ascospores throughout the summer. The environmental conditions and seasonal timings associated with O. agrostis ascospore release are unknown. The objectives of this research were to (i) determine the influence of light and relative humidity on ascospore release in a controlled environment, (ii) document the seasonal and daily discharge patterns of ascospores in the field, and (iii) elucidate environmental conditions that promote ascospore release under field conditions. In a growth chamber, a sharp decrease (100 to approximately 50%; 25 degrees C) in relative humidity resulted in a rapid (1- to 3-h) discharge of ascospores, regardless of whether pseudothecia were incubated in constant light or dark. In the field, daily ascospore release increased between 1900 and 2300 h and again between 0700 and 1000 h local time. The release of ascospores occurred primarily during the early morning hours when relative humidity was decreasing and the canopy began to dry, or during evening hours when relative humidity was low and dew began to form. Few ascospores were released between 1100 and 1800 h when the bentgrass canopy was dry. The release of ascospores also was triggered by precipitation. Of the ascospores collected during precipitation events, 87% occurred within 10 h of the beginning of each event. PMID:18943368

Kaminski, John E; Dernoeden, Peter H; O'Neill, Nichole R

2005-11-01

156

[Fluorescence parameters of chlorophyll in leaves of caules plants in different environmental conditions].  

PubMed

The functional state of medicinal plants of Convallaria majalis L., Vaccinium vitis-idaeae L., Arctostaphylos uva-ursi L. in connection with heavy metal accumulation in their leaves under man impact was studied by the pulse-amplitude-modulation (PAM) fluorometric method. The relative yield of variable fluorescence (F(v)/F(m)), induction of fluorescence of chlorophyll, and fluorescence quenching processes in leaves at different distances from the local Kirov-Sovetsk, Kirov-Omutninsk road in Kirov region were analyzed. Changes in biophysical characteristics with the increasing content of heavy metals in leaves were demonstrated. The most informative characteristic is F(v)/F(m). Its value correlates with the activity of the photosynthetic apparatus and reflects the potential effeciency of photosynthesis. The better are the environmental conditions of plant growth, the higher is the F(v)/F(m) ratio and the lower is its average statistical deviation. Fluorescence induction curves do not always vary in shape under our ecological conditions, indicating relatively favorable conditions at places of plant growth investigated. The rate of the environmental pollution in the investigated region is not critical, since the content of heavy metal in leaves does not change considerably with the distance from the road. PMID:16358792

Iakovleva, O V; Talipova, E V; Kukarskikh, G P; Krendeleeva, T E; Rubin, A B

157

Evaluating GIS for establishing and monitoring environmental conditions of oil fields  

SciTech Connect

Good management of an oil field and compliance with ever-increasing environmental regulations is enhanced by technologies that improve a company`s understanding of field/production facilities and environmental conditions that have occurred to both through time. In Nigeria, Kazakhstan, Indonesia, and offshore Cabinda, remote sensing, computer-aided drafting (CAD) and Global Positioning System (GPF) technologies have effectively been used by Chevron to provide accurate maps of facilities and to better understand environmental conditions. Together these proven technologies have provided a solid and cost-effective base for planning field operation, verifying well and seismic locations, and locating sampling sites. The end product of these technologies is often locations, and locating sampling sites. The end product of these technologies is often cartographic-quality hardcopy images and maps for use in the office and field. Chevron has been evaluating the capability of Geographical Information System (GIS) technology to integrate images, maps, and tabular data into a useful database that can help managers and workers better evaluate conditions in an oil field, plan new facilities, and monitor/predict trends (for example, of air emissions, groundwater, soil chemistry, subsidence, etc.). Remote sensing, CAD (if formatted properly), and GPS data can be integrated to establish the spatial or cartographic base of the GIS. A major obstacle to establishing a sophisticated GIS for an overseas operation is the initial cost of data collection and conversion from legacy data base management systems and hardcopy to appropriate digital format. However, Chevron routinely uses GIS for oil spill modeling and is now using GIS in the field for integrating GPS data with field observations and programs.

Pfeil, R.W.; Ellis, J.W. [Chevron Overseas Petroleum Inc., San Ramon, CA (United States)

1995-04-01

158

Canine dirofilariosis under specific environmental conditions of the Eastern Slovak Lowland.  

PubMed

The aim of the present study was to collect data from Eastern Slovak Lowland, southern Slovakia, to assess risk of the spread of canine dirofilariosis. Climate and environmental conditions in the Eastern Slovak Lowland are ideally suitable for the occurrence of vector-borne diseases. In the past, an endemic locality of dangerous mosquito transmitted malaria was found in this area. Today, another zoonotic parasitic disease threatens--dirofilariosis. The results of the first detailed study revealed a 34.44% prevalence in dogs harbouring dirofilariae. D. repens was diagnosed in all infected specimen, with 2 individuals being co-infected also with D. immitis. PMID:22462446

Iglódyová, Adriana; Miterpáková, Martina; Hurníková, Zuzana; Antolová, Daniela; Dubinský, Pavol; Letková, Valéria

2012-03-23

159

Small Scale Solar Cooling Unit in Climate Conditions of Latvia: Environmental and Economical Aspects  

NASA Astrophysics Data System (ADS)

The paper contributes to the analyses from the environmental and economical point of view of small scale solar cooling system in climate conditions of Latvia. Cost analyses show that buildings with a higher cooling load and full load hours have lower costs. For high internal gains, cooling costs are around 1,7 €/kWh and 2,5 €/kWh for buildings with lower internal gains. Despite the fact that solar cooling systems have significant potential to reduce CO2 emissions due to a reduction of electricity consumption, the economic feasibility and attractiveness of solar cooling system is still low.

Jaunzems, Dzintars; Veidenbergs, Ivars

2010-01-01

160

Oxidative stress in limpets exposed to different environmental conditions in the Beagle Channel.  

PubMed

The aim of this work was to study the oxidative profile of digestive glands of two limpets species (Nacella (Patinigera) magellanica and Nacella (Patinigera) deaurata) exposed to different environmental conditions. The intertidal population of N. (P.) magellanica is subjected to a wide variety of stresses not experienced by N. (P.) deaurata. Although a typical electron paramagnetic resonance (EPR) spectrum of ascorbyl radical in digestive gland from both limpets was observed, neither ascorbyl radical content nor the ascorbyl radical content/ascorbate content ratio was significantly different, suggesting that the difference in the environmental conditions did not appear to be responsible for developing alterations in the oxidative status of both organisms at the hydrophilic level (e.g. cytosol). Lipid peroxidation in the digestive glands was estimated, both as the content of thiobarbituric acid reactive substances (TBARS) and as the content of lipid radicals assessed by EPR, in both organisms. TBARS and lipid radical content were 34.8 and 36.5%, respectively, lower in N. (P.) magellanica as compared to N. (P.) deaurata. On the other hand, total iron content and the rate of generation of superoxide anion were 47.9 and 51.4%, respectively, lower in N. (P.) magellanica as compared to N. (P.) deaurata. The activity of catalase and superoxide dismutase (SOD) was 35.3 and 128.6% higher in N. (P.) magellanica as compared to N. (P.) deaurata, respectively. No significant differences were determined between the digestive glands of both molluscs regarding the content of total thiols. alpha-Tocopherol and beta-carotene content were significantly lower in N. (P.) magellanica as compared to N. (P.) deaurata. A distinctive EPR signal for the adduct Fe--MGD--NO (g = 2.03 and a(N) = 12.5 G) was detected in the homogenates of digestive glands of both limpets. A significant difference in the content of the Fe-MGD-NO adduct in digestive glands from N. (P.) magellanica and N. (P.) deaurata (491 +/- 137 and 839 +/- 63 pmol/g FW, respectively) was observed. Taken as a whole, the data presented here indicated that coping with environmental stressing conditions requires a complex adjustment of the physiological metabolic pathways to ensure survival by minimizing intracellular damage. It is likely that N. (P.) magellanica has a particular evolutionary adaptation to extreme environmental conditions by keeping iron content low and antioxidant activities high. PMID:15312715

Malanga, Gabriela; Estevez, Maria Susana; Calvo, Jorge; Puntarulo, Susana

2004-09-20

161

Physiological and genetic analysis of Arabidopsis thaliana anthocyanin biosynthesis mutants under chronic adverse environmental conditions  

PubMed Central

Anthocyanin production is a characteristic response of flowering plants to unfavourable environmental conditions. The potential roles of flavonoids and anthocyanins in plant growth were investigated by growing Arabidopsis thaliana anthocyanin production mutants (transparent testa) under limiting nitrogen and high light conditions. Inability to produce kaempferol or subsequent intermediate compounds by some transparent testa lines was correlated with less biomass accumulation in mature plants compared with wild-type control plants under all growth conditions tested. However, under both limiting nitrogen and high light chronic stress conditions, mutant lines defective in later steps of the anthocyanin production pathway produced the same or more biomass than wild-type plants. No difference in senescence between transparent testa and wild-type plants was found using chlorophyll catabolism and SAG12 expression measurements, and no mutants were impaired in the ability to remobilize nutrients from the vegetative to reproductive tissues. Moreover, the absence of anthocyanin and/or upstream flavonoids does not affect the ability of plants to respond to limiting nitrogen by reducing photosynthetic capacity. These results support a role for kaempferol and quercetin accumulation in normal plant growth and development. Further, the absence of anthocyanins has no effect on plant growth under the chronic stress conditions tested.

Rothstein, Steven J.

2013-01-01

162

Differential effects of chronic unpredictable stress on hippocampal CB1 receptors in male and female rats  

Microsoft Academic Search

Chronic unpredictable mild stress (CMS), an animal model of depression, downregulates hippocampal CB1 receptors in adult male rats. Given that endocannabinoids are implicated in modulating stress and anxiety and that women are vulnerable to stress-related disorders, we tested the effects of CMS on both female and male rats. Gonadectomized (gndx) and gonadally intact male and female rats were exposed to

Christian G. Reich; Michael E. Taylor; Margaret M. McCarthy

2009-01-01

163

Reduction in preference for saccharin by repeated unpredictable stress in mice and its prevention by imipramine  

Microsoft Academic Search

The present study set out to establish the chronic mild stress (CMS) animal model of depression in male CD-1 mice, a commonly used mouse strain. Mice were exposed to a series of mild stressors (e.g. soiled bedding, paired housing, cage tilt, white noise) presented in a continuous unpredictable fashion. Intermittently, CMS was discontinued and the mice were presented with both

Andrew Harkin; Diarmaid D. Houlihan; John P. Kelly

2002-01-01

164

Reported physical symptoms elicited by unpredictable events and the Type A coronary-prone behavior pattern  

Microsoft Academic Search

Hypothesized that unpredictable aversive events are causally linked to physical symptom reporting and that the Type A coronary-prone behavior pattern affects symptom reporting, such that Type A individuals fail to report symptoms when they expect to continue working on a task as compared to when they believe they have completed it. In the present study, 120 Type A and Type

Gerdi Weidner; Karen A. Matthews

1978-01-01

165

Reduction of sucrose preference by chronic unpredictable mild stress, and its restoration by a tricyclic antidepressant  

Microsoft Academic Search

Rats exposed chronically (5–9 weeks) to a variety of mild unpredictable stressors showed a reduced consumption of and preference for saccharin or sucrose solutions. Preference deficits took at least 2 weeks to develop and were maintained for more than 2 weeks after termination of the stress regime. Sucrose preference was unaffected by 1 week of treatment with the tricyclic antidepressant

P. Willner; A. Towell; D. Sampson; S. Sophokleous; R. Muscat

1987-01-01

166

Alcohol Selectively Reduces Anxiety but Not Fear: Startle Response During Unpredictable Versus Predictable Threat  

Microsoft Academic Search

Recent theory and empirical research have suggested that fear and anxiety are distinct processes with separable neurobiological substrates. Furthermore, a laboratory procedure has been developed to manipulate fear versus anxiety independently via administration of predictable or unpredictable electric shock, respectively. Benzodiazepines appear to selectively reduce anxiety but not fear in this procedure. The primary aim of this experiment was to

Christine A. Moberg; John J. Curtin

2009-01-01

167

Uncontrollability and Unpredictability in Post-Traumatic Stress Disorder: An Animal Model  

Microsoft Academic Search

The disturbances observed in animals subjected to unpredictable and uncontrollable aversive events resemble post-traumatic stress disorder (PTSD) symptoms and thus may constitute an animal model of this disorder. It is argued that the similarity between animals' symptoms and those of trauma victims may reflect common etiological factors. Relevant experiments in which animals exhibit generalized fear and arousal, discrete fear of

Edna B. Foa; Richard Zinbarg; Barbara Olasov Rothbaum

1992-01-01

168

Qualitative research in marketing : Road-map for a wilderness of complexityand unpredictability  

Microsoft Academic Search

Purpose – To discuss and analyse three themes in qualitative research in marketing which are objects of both frustration and confusion: analysis and interpretation; theory generation; and a quest for scientific pluralism and individual researcher lifestyles. Design\\/methodology\\/approach – Underpinning the discussion is that complexity, ambiguity, fuzziness, chaos, change, uncertainty and unpredictability are characteristics of a market economy; that qualitative and

Evert Gummesson

2005-01-01

169

A Sampling-Based Motion Planning Approach to Maintain Visibility of Unpredictable Targets  

Microsoft Academic Search

This paper deals with the surveillance problem of computing the motions of one or more robot observers in order to maintain visibility of one or several moving targets. The targets are assumed to move unpredictably, and the distribution of obstacles in the workspace is assumed to be known in advance. Our algorithm computes a motion strategy by maximizing the shortest

Rafael Murrieta-cid; Benjamín Tovar; Seth Hutchinson

2005-01-01

170

Modulation of tropical convective systems by environmental conditions as observed from multiple satellite measurements  

NASA Astrophysics Data System (ADS)

During the Indoex experiment, a specific effort was done in LMD, France, for collecting the satellite data relevant to the region and period, and put them in a well conditioned data base. Meteosat-5 was moved by EUMETSAT over the Indian Ocean, and is the leading satellite for the studies presented here. METEOSAT allows the study and tracking of the convective systems and events, as well as estimation of the upper tropospheric humidity. Other satellite information on the water vapour in the atmosphere or precipitation come from microwave instruments as SSM/I or the instruments of TRMM. Concerning the radiative budget components, ScaRaB on the Russian satellite RESURS was providing outgoing radiative fluxes. All this information is combined here in order to study the fluctuations of convection at different time space scales and its relationship to environmental conditions such as humidity, sea surface temperature,…

Desbois, Michel; Roca, Remy; Viollier, Michel; Rao, Kusuma G.; Monge, Jean-Louis

2003-04-01

171

The first "space" vegetables have been grown in the "SVET" greenhouse using controlled environmental conditions  

NASA Astrophysics Data System (ADS)

The paper describes the "SVET" project—a new generation of space greenhouse with small dimensions. Through the use of a minicomputer, "SVET" is fully capable of automatically operating and controlling environmental systems for higher plant growth. A number of preliminary studies have shown the radish and cabbage to be potentially important crops for CELSS (Closed Environmental Life Support System). The "SVET" space greenhouse was mounted on the "CRYSTAL" technological module docked to the Mir orbital space station on 10 June 1990. Soviet cosmonauts Balandin and Solovyov started the first experiments with the greenhouse on 15 June 1990. Preliminary results of seed cultivation over an initial 54-day period in "SVET" are presented. Morphometrical characteristics of plants brought back to Earth are given. Alteration in plant characteristics, such as growth and developmental changes, or morphological contents were noted. A crop of radish plants was harvested under microgravity conditions. Characteristics of plant environmental control parameters and an estimation of functional properties of control and regulation systems of the "SVET" greenhouse in space flight as received via telemetry data is reported.

Ivanova, T. N.; Bercovich, Yu. A.; Mashinskiy, A. L.; Meleshko, G. I.

172

The first "space" vegetables have been grown in the "SVET" greenhouse using controlled environmental conditions.  

PubMed

The paper describes the "SVET" project--a new generation of space greenhouse with small dimensions. Through the use of a minicomputer, "SVET" is fully capable of automatically operating and controlling environmental systems for higher plant growth. A number of preliminary studies have shown the radish and cabbage to be potentially important crops for CELSS (Closed Environmental Life Support System). The "SVET" space greenhouse was mounted on the "CRYSTAL" technological module docked to the Mir orbital space station on 10 June 1990. Soviet cosmonauts Balandin and Solovyov started the first experiments with the greenhouse on 15 June 1990. Preliminary results of seed cultivation over an initial 54-day period in "SVET" are presented. Morphometrical characteristics of plants brought back to Earth are given. Alteration in plant characteristics, such as growth and developmental changes, or morphological contents were noted. A crop of radish plants was harvested under microgravity conditions. Characteristics of plant environmental control parameters and an estimation of functional properties of control and regulation systems of the "SVET" greenhouse in space flight as received via telemetry data is reported. PMID:11541646

Ivanova, T N; Bercovich YuA; Mashinskiy, A L; Meleshko, G I

1993-08-01

173

Using magnetically responsive tea waste to remove lead in waters under environmentally relevant conditions.  

PubMed

We report the use of a simple yet highly effective magnetite-waste tea composite to remove lead(II) (Pb(2+)) ions from water. Magnetite-waste tea composites were dispersed in four different types of water-deionized (DI), artificial rainwater, artificial groundwater and artificial freshwater-that mimic actual environmental conditions. The water samples had varying initial concentrations (0.16-5.55 ppm) of Pb(2+) ions and were mixed with the magnetite-waste tea composite for at least 24 hours to allow adsorption of the Pb(2+) ions to reach equilibrium. The magnetite-waste tea composites were stable in all the water samples for at least 3 months and could be easily removed from the aqueous media via the use of permanent magnets. We detected no significant leaching of iron (Fe) ions into the water from the magnetite-waste tea composites. The percentage of Pb adsorbed onto the magnetite-waste tea composite ranged from ?70% to 100%; the composites were as effective as activated carbon (AC) in removing the Pb(2+) ions from water, depending on the initial Pb concentration. Our prepared magnetite-waste tea composites show promise as a green, inexpensive and highly effective sorbent for removal of Pb in water under environmentally realistic conditions. PMID:23818955

Yeo, Siang Yee; Choi, Siwon; Dien, Vivian; Sow-Peh, Yoke Keow; Qi, Genggeng; Hatton, T Alan; Doyle, Patrick S; Thio, Beng Joo Reginald

2013-06-20

174

Environmental conditions associated with lesions in introduced free-ranging sheep in Hawai‘i  

USGS Publications Warehouse

Wildlife species which have been translocated between temperate and tropical regions of the world provide unique opportunities to understand how disease processes may be affected by environmental conditions. European mouflon sheep (Ovis gmelini musimon) from the Mediterranean Islands were introduced to the Hawaiian Islands for sport hunting beginning in 1954 and were subsequently hybridized with feral domestic sheep (O. aries), which had been introduced in 1793. Three isolated mouflon populations have become established in the Hawaiian Islands but diseases in these populations have been little studied. The objective of this study was to evaluate and compare gross and histologic lesions in respiratory, renal, and hepatic systems of free-ranging sheep in two isolated volcanic environments on Hawai‘i Island. Tissue and fecal samples were collected in conjunction with population reductions during February 2011. We found gross or histologic evidence of lungworm infection in 44/49 sheep from Mauna Loa which were exposed to gaseous emissions from K?lauea Volcano. In contrast, only 7/50 sheep from Mauna Kea had lesions consistent with lungworm, but Mauna Kea sheep had significantly more upper respiratory tract inflammation and hyperplasia consistent with chronic antigenic stimulation, possibly associated with exposure to fine airborne particulates during extended drought conditions. We hypothesize that gasses from K?lauea Volcano contributed to severity of respiratory disease principally associated with chronic lungworm infections at Mauna Loa; however, there were numerous other potentially confounding environmental factors and interactions that merit further investigation.

Powers, Jenny G.; Duncan, Colleen G.; Spraker, Terry R.; Schuler, Bridget A.; Hess, Steven C.; Faford, Jonathan K. J.; Sin, Hans

2013-01-01

175

Environmental and Geometrical Conditions to Sustain Crevice Corrosion in Alloy 22  

SciTech Connect

Alloy 22 (N06022) is highly resistant to localized corrosion. Under aggressive environmental conditions Alloy 22 may be susceptible to crevice corrosion in hot chloride (Cl{sup -}) solutions. The objective of the present work was to explore the environmental and geometrical conditions for crevice corrosion to occur. Electrochemical tests were performed using PCA and prismatic mill annealed Alloy 22 specimens in chloride solutions. Crevice corrosion current density was found to be a function of applied potential. i{sub CREV} values ranged from 40 {micro}A/cm{sup 2} to 20 mA/cm{sup 2}. Such low values of current density explained the absence of pitting corrosion in Alloy 22 at any potential. Decreasing of the effective diffusion distance in a propagating crevice is thought to cause crevice corrosion stifling or repassivation after long anodic polarization. Crevice corrosion breakdown potential is expected to decrease with potential scan rate, approaching repassivation potential for low scan rates. The lowest corrosion potential of Alloy 22 in hydrochloric acid solutions at which active corrosion exists was proposed as the lowest possible repassivation potential for crevice corrosion.

Carranza, R M; Rodr?guez, M A; Rebak, R B

2006-11-10

176

Impacts of environmental conditions on the sorption of volatile organic compounds onto tire powder.  

PubMed

A series of batch tests were performed and the impacts of environmental conditions and phase change on the sorption of volatile organic compounds (VOCs) were investigated. Benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene were selected as target VOCs. Sorption of VOCs onto tire powder was well demonstrated by a linear-partitioning model. Water-tire partition coefficients of VOCs (not tested in this study) could be estimated using a logarithmic relationship between observed water-tire partition coefficients and octanol-water partition coefficients of the VOCs tested. The target VOCs did not seem to compete with other VOCs significantly when sorbed onto the tire powder for the range of concentrations tested. The influence of environmental conditions, such as pH and ionic strength also did not seem to be significant. Water-tire partition coefficients of benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene decreased as the sorbent dosage increased. However, they showed stable values when the sorbent dosage was greater than 10 g/L. Air-tire partition coefficient could be extrapolated from Henry's law constants and water-tire partition coefficient of VOCs. PMID:17889437

Oh, Dong I; Nam, Kyongphile; Park, Jae W; Khim, Jee H; Kim, Yong K; Kim, Jae Y

2007-08-22

177

The transcriptomic responses of the eastern oyster, Crassostrea virginica, to environmental conditions.  

PubMed

Understanding the mechanisms by which organisms adapt to environmental conditions is a fundamental question for ecology and evolution. In this study, we evaluate changes in gene expression of a marine mollusc, the eastern oyster Crassostrea virginica, associated with the physico-chemical conditions and the levels of metals and other contaminants in their environment. The results indicate that transcript signatures can effectively disentangle the complex interactive gene expression responses to the environment and are also capable of disentangling the complex dynamic effects of environmental factors on gene expression. In this context, the mapping of environment to gene and gene to environment is reciprocal and mutually reinforcing. In general, the response of transcripts to the environment is driven by major factors known to affect oyster physiology such as temperature, pH, salinity, and dissolved oxygen, with pollutant levels playing a relatively small role, at least within the range of concentrations found in the studied oyster habitats. Further, the two environmental factors that dominate these effects (temperature and pH) interact in a dynamic and nonlinear fashion to impact gene expression. Transcriptomic data obtained in our study provide insights into the mechanisms of physiological responses to temperature and pH in oysters that are consistent with the known effects of these factors on physiological functions of ectotherms and indicate important linkages between transcriptomics and physiological outcomes. Should these linkages hold in further studies and in other organisms, they may provide a novel integrated approach for assessing the impacts of climate change, ocean acidification and anthropogenic contaminants on aquatic organisms via relatively inexpensive microarray platforms. PMID:21426432

Chapman, Robert W; Mancia, Annalaura; Beal, Marion; Veloso, Artur; Rathburn, Charles; Blair, Anne; Holland, A F; Warr, G W; Didinato, Guy; Sokolova, Inna M; Wirth, Edward F; Duffy, Edward; Sanger, Denise

2011-02-24

178

Definition of testing procedures to check performance of ZnO surge arresters in different environmental conditions.  

National Technical Information Service (NTIS)

The performance of surge arresters under different environmental conditions involves three main aspects: the strength of the external insulation; heating of the internal active part of the surge arrester associated with voltage unbalance along the arreste...

A. Bargigia M. de Nigris A. Pigini A. Sironi

1992-01-01

179

Environmental Monitoring and Assessment Program; Surface Waters: Field Operations and Methods Manual for Measuring the Ecological Condition of Wadeable Streams.  

National Technical Information Service (NTIS)

This document describes procedures for collecting data, samples, and information about biotic assemblages, environmental measures, or attributes of indicators of stream ecosystem condition. As such, it represents one of the tools developed by the Environm...

D. J. Klemm D. V. Peck J. M. Lazorchak

1998-01-01

180

Use of Indicator Species as a Means of Assessing the Environmental Condition of the Weeks Bay National Estuarine Reserve.  

National Technical Information Service (NTIS)

This project evaluated the environmental condition of the marsh/estuarine habitat of the Weeks Bay National Estuarine Reserve by characterizing the specific major habitat type and its animal associates and by assessing the occurrence and abundance of pre-...

J. J. Dindo K. R. Marion

1987-01-01

181

Assessing income-wise household environmental conditions and disease profile in urban areas: Study of an Indian city  

Microsoft Academic Search

The main objectives of the present study are: (i) to assess the income-wise household environmental conditions of the sampled\\u000a households in Aligarh city, (ii) to examine income-wise disease profile of the population, (iii) to assess the relationship\\u000a between income and four most occurring diseases, (iv) draw out inter-relationship between income, non-ideal household environmental\\u000a conditions and environment related diseases. The quality

Atiqur Rahman

2006-01-01

182

[Retrospective analysis of influence of environmental conditions on growth parameters of White Sea edible mussels Mytilus edulis].  

PubMed

Retrospective analysis of influence of environmental conditions on growth parameters of White Sea edible mussels Mytilus edulis has been done by measurements of successive annual rings on shell surface. Analysis by non-linear criterion and Bertalanffy's growth equation allows to deduce that the best environmental condition for edible mussels growth was in 1999 (population from Kastyan island region) and in 2001 (population of Malaya Pir-guba region). The worst one was in 1998 for both populations. PMID:17168474

Zotin, A A; Ozerniuk, N D

183

Environmental conditions and phosphorus removal in Florida lakes and wetlands inhabited by Hydrilla verticillata (Royle): implications for invasive species management  

Microsoft Academic Search

Hydrilla verticillata is considered the most problematic aquatic plant in the United States. In south Florida, Hydrilla dominance has also been documented in treatment wetlands. This paper characterizes (1) environmental conditions which favor\\u000a Hydrilla growth and (2) understand its nutrient removal capability. Despite its occurrence over a wide range of environmental conditions,\\u000a Hydrilla abundance increased with increasing pH, alkalinity, total

Binhe Gu

2006-01-01

184

Sudden changes in environmental conditions do not increase invasion risk in grassland  

NASA Astrophysics Data System (ADS)

After direct habitat transformation, biological invasions are considered to be the second most important threat to biodiversity. A better understanding of the factors affecting invasion success in new areas is crucial, and may provide insight into potential control actions. We hypothesized that invasion risk increases in habitats undergoing a sudden change in the disturbance regime or environmental conditions. For testing this assumption we initiated a seed sowing experiment while introducing two novel treatments, mowing twice and fertilizer application, in two grassland sites (one dryer and one mesic) in Romania. The seeds of two invasive species, Solidago canadensis and Rudbeckia laciniata, and two resident natives of similar seed sizes, life-forms and strategies were sowed in treated and control plots, and seed germination, seedling establishment and growth were followed during four months. Contrary to our expectations, there was no difference in the treatment effects on seed germination and seedling establishment between species, while there was on seedling vigour of the larger seeded species in the dryer grassland site, where the native had a higher performance especially in increased nutrient conditions. Indifferently from applied treatments, invasive species had greater cumulative germination in the mesic site, while natives were far more successful in seedling establishment in the drier site. At the same time, seed size was found to be a very important factor explaining germination and establishment success, with large seeded species outperforming small seeded species in any circumstances. Our results call the attention upon management interventions in mesic, productive grassland sites opening colonization windows for the recruitment of those invasive species of which ecological requirements correspond to local environmental conditions.

Ruprecht, Eszter; Fenesi, Annamária; Nijs, Ivan

2013-02-01

185

Effects of simulated environmental conditions on glucocorticoid metabolite measurements in white-tailed deer feces.  

PubMed

Environmental conditions may influence fecal glucocorticoid metabolite measurements if feces cannot be collected immediately after deposition. To evaluate the influence of environmental conditions on fecal glucocorticoid metabolite concentrations, we exposed fresh fecal samples to 1 of 5 simulated conditions: (1) room temperature (22 degrees C), (2) high heat (38 degrees C), (3) alternating high heat and room temperature cycle, (4) alternating freezing (-20 degrees C) and room temperature cycle, and (5) simulated rainfall (0.85 cm every other day at 22 degrees C) for 7 days. We collected fresh white-tailed deer (Odocoileus virginianus) feces at various times pre- and post-adrenocorticotropin injection to provide samples with initially low (n=5), medium (n=5), and high (n=5) glucocorticoid concentrations. Feces were mixed thoroughly and then allocated into five 10-g samples. Also, a 5-g sub-sample was taken from each fecal mass prior to treatment and stored at -20 degrees C until assayed. We subsampled from all treatments once every 24-h for 7 days. Fecal samples were assayed using [125I]corticosterone radioimmunoassay kits. Fecal glucocorticoid metabolites in all three groups in the simulated rainfall treatment and the low group in the alternating freezing and room temperature treatment increased significantly over the 7-day period. We believe increased microbial metabolism of fecal glucocorticoids may partly explain these results. Other biochemical processes (e.g., cleavage of conjugate side groups from hormone metabolites by non-microbial action or release of glucocorticoids from lipid micelles) may also have increased fecal glucocorticoid measurements. Our findings suggest that fecal samples exposed to rainfall for one week may artificially inflate fecal glucocorticoid measurements. Thus, researchers should recognize the potential bias when collecting fecal samples exposed to rainfall. Non-fresh samples may prove useful when care is taken to address the elevation in immunoreactive glucocorticoid concentrations. PMID:12225762

Washburn, Brian E; Millspaugh, Joshua J

2002-07-01

186

Evolution, Stress, and Sensitive Periods: The Influence of Unpredictability in Early Versus Late Childhood on Sex and Risky Behavior  

Microsoft Academic Search

According to a recent evolutionary life history model of development proposed by Ellis, Figueredo, Brumbach, and Schlomer (2009), growing up in harsh versus unpredictable environments should have unique effects on life history strategies in adulthood. Using data from the Minnesota Longitudinal Study of Risk and Adaptation, we tested how harshness and unpredictability experienced in early childhood (age 0–5) versus in

Jeffry A. Simpson; Vladas Griskevicius; Sally I-Chun Kuo; Sooyeon Sung; W. Andrew Collins

2012-01-01

187

A role for anterior thalamic nuclei in affective cognition: interaction with environmental conditions.  

PubMed

Damage to anterior thalamic nuclei (ATN) is a well-known cause of diencephalic pathology that produces a range of cognitive deficits reminiscent of a hippocampal syndrome. Anatomical connections of the ATN also extend to cerebral areas that support affective cognition. Enriched environments promote recovery of declarative/relational memory after ATN lesions and are known to downregulate emotional behaviors. Hence, the performance of standard-housed and enriched ATN rats in a range of behavioral tasks engaging affective cognition was compared. ATN rats exhibited reduced anxiety responses in the elevated plus maze, increased activity and reduced corticosterone responses when exploring an open field, and delayed acquisition of a conditioned contextual fear response. ATN rats also exhibited reduced c-Fos and phosphorylated cAMP response element-binding protein (pCREB) immunoreactivity in the hippocampal formation and the amygdala after completion of the contextual fear test. Marked c-Fos hypoactivity and reduced pCREB levels were also evident in the granular retrosplenial cortex and, to a lesser extent, in the anterior cingulate cortex. Unlike standard-housed ATN rats, enriched ATN rats expressed virtually no fear of the conditioned context. These results show that the ATN regulate affective cognition and that damage to this region may produce markedly different behavioral effects as a function of environmental housing conditions. PMID:23436341

Dupire, Alexandra; Kant, Patricia; Mons, Nicole; Marchand, Alain R; Coutureau, Etienne; Dalrymple-Alford, John; Wolff, Mathieu

2013-02-25

188

Antecedent growth conditions alter retention of environmental Escherichia coli isolates in transiently wetted porous media.  

PubMed

The physical transport of Escherichia coli in terrestrial environments may require control to prevent its dissemination from potential high-density sources, such as confined animal feedlot operations. Biobarriers, wherein convective flows carrying pathogens pass through a porous matrix with high retentive capacity, may present one such approach. Eight environmental E. coli isolates were selected to conduct operational retention tests (ORT) with potential biobarrier materials Pyrax or dolomite, or silica glass as control. The conditions in the ORT were chosen to simulate conditioning by manure solutes, a pulse application of a bacterial load followed by rainfall infiltration, and natural drainage. Removal was limited, and likely caused by the relatively high velocities during drainage, and the conditioning of otherwise favorable adhesion sites. Flagella-mediated motility showed the strongest correlation to biobarrier retention. Significant variability was observed across the E. coli isolates, but consistently higher retention was observed for cells with external versus intestinal pregrowth histories. E. coli O157:H7 was retained the least with all examined matrices, while E. coli K-12 displayed moderate retention and may not serve as representative model strain. Pyrax is a good candidate biobarrier material given its superior removal ability across the tested E. coli strains. PMID:19174909

Yang, Hsiao-Hui; Morrow, Jayne B; Grasso, Domenico; Vinopal, Robert T; Dechesne, Arnaud; Smets, Barth F

2008-12-15

189

Raman spectroscopy of a single living cell in environmentally stressed conditions  

NASA Astrophysics Data System (ADS)

Living cells initiate a stress response in order to survive environmentally stressful conditions. We monitored changes in the Raman spectra of an optically trapped Saccharomyces cerevisiae yeast cell under normal and hyperosmotic stress conditions. When the yeast cells were challenged with a high concentration of glucose so as to exert hyperosmotic stress, it was shown that two chemical substances - glycerol and ethanol - could be monitored in real time in a single cell. The volume of the detection area of our confocal microspectrometer is approximately 1 fL. The average quantities of detected glycerol and ethanol are about 300 attomol and 700 attomol respectively. This amounts to the detection of approximately 108 glycerol molecules and 4 X 108 ethanol molecules after 36 min of hyper osmotic stress. Besides this, we also optically trapped a single yeast cell for up to three hours under normal conditions and monitored the changes in the Raman spectra during the lag phase of its growth and the G1 phase of its cell cycle. During the lag phase the cell synthesises new proteins and the observed behavior of the peaks corresponding to these proteins as well as those of RNA served as a sensitive indicator of the adaptation of the cell to its changed environment. The changes observed in the Raman spectra of a trapped yeast cell in the late G1 phase or the beginning of S phase corresponded to the growth of a bud.

Singh, Gajendra P.; Creely, Caitriona; Volpe, Giovanni; Grotsch, Helga; Petrov, Dmitri

2005-08-01

190

Imprint of past and present environmental conditions on microbiology and biogeochemistry of coastal Quaternary sediments  

NASA Astrophysics Data System (ADS)

To date, North Sea tidal-flat sediments have been intensively studied down to a depth of 5 m below seafloor (mbsf). However, little is known about the biogeochemistry, microbial abundance, and activity of sulfate reducers as well as methanogens in deeper layers. In this study, two 20 m-long cores were retrieved from the tidal-flat area of Spiekeroog Island, NW Germany. The drill sites were selected with a close distance of 900 m allowing to compare two depositional settings: first, a paleo-channel filled with Holocene sediments and second, a mainly Pleistocene sedimentary succession. Analyzing these cores, we wanted to test to which degree the paleo-environmental imprint is superimposed by present processes. In general, the numbers of bacterial 16S rRNA genes are one to two orders of magnitude higher than those of Archaea. The abundances of key genes for sulfate reduction and methanogenesis (dsrA and mcrA) correspond to the sulfate and methane profiles. A co-variance of these key genes at sulfate-methane interfaces and enhanced ex situ AOM rates suggest that anaerobic oxidation of methane may occur in these layers. Microbial and biogeochemical profiles are vertically stretched relative to 5 m-deep cores from shallower sediments in the same study area, but still appear compressed compared to deep sea sediments. Our interdisciplinary analysis shows that the microbial abundances and metabolic rates are elevated in the Holocene compared to Pleistocene sediments. However, this is mainly due to present environmental conditions such as pore water flow and organic matter availability. The paleo-environmental imprint is still visible but superimposed by these processes.

Beck, M.; Riedel, T.; Graue, J.; Köster, J.; Kowalski, N.; Wu, C. S.; Wegener, G.; Lipsewers, Y.; Freund, H.; Böttcher, M. E.; Brumsack, H.-J.; Cypionka, H.; Rullkötter, J.; Engelen, B.

2011-01-01

191

Effect of reproductive modes and environmental heterogeneity in the population dynamics of a geographically widespread clonal desert cactus  

Microsoft Academic Search

The dynamics of plant populations in arid environments are largely affected by the unpredictable environmental conditions\\u000a and are fine-tuned by biotic factors, such as modes of recruitment. A single species must cope with both spatial and temporal\\u000a heterogeneity that trigger pulses of sexual and clonal establishment throughout its distributional range. We studied two populations\\u000a of the clonal, purple prickly pear

María C. Mandujano; Jordan Golubov; Laura F. Huenneke

2007-01-01

192

Effect of modified weather and environmental conditions on the regional ozone load  

NASA Astrophysics Data System (ADS)

Near-surface ozone plays an important role in the formation of the photochemical air pollution and affects both vegetation and human health. Recently, it has also been shown that the indirect radiative forcing of climate change through ozone effecting on the land carbon sink could be an important factor and can induce a positive feedback for global warming. This impact study examines the connections between the possible changes of atmospheric and environmental properties due to the regional climate change and the tropospheric ozone load on different vegetations over Central European region. For this purpose, concentration and flux-based ozone metrics with their spatial and seasonal variability were estimated under different weather and environmental conditions. Simulations were performed with a sophisticated deposition model using different regional climate scenarios with a special emphasis on the possible modifications of the obscured factors of the ozone deposition (water vapour pressure, soil water deficit, etc.). Additionally, different stress-function parameterizations ant their effect on the results were also analysed.

Komjáthy, E.; Mészáros, R.; Lagzi, I.

2010-09-01

193

Evaluation of uncertainties in loadings on offshore structures due to extreme environmental conditions  

SciTech Connect

This paper summarizes results from a Canadian Standards Association (CSA) sponsored study of the uncertainties associated with extreme (1,000 to 10,0000-yr return periods) environmental loadings acting on offshore structures (Bea, 1991). The evaluations of the loadings addressed loading effects that resulted from dynamic and nonlinear interactions of the structures. Loading uncertainties were organized and characterized in two categories: (1) inherent randomness (aleotory uncertainty), and (2) analytical variability (epistemic uncertainty). The study addressed the global ultimate limit state performance of three structures designed according to the provisions on the draft CSA guidelines (1989a, 1989b) for offshore structures: (1) a concrete Gravity Base Structure (GBS) located off the East coast of Canada (Hibernia), (2) a steel pile template located on the Scotian Shelf off Sable Island, and (3) a caisson retained island located in the Mackenzie Delta area of the Beaufort Sea (Amuligak). The results of this study indicate that, based on presently available information and data, it is often not possible to develop unambiguous characterizations of uncertainties. The different technical communities that background environmental conditions and forces (storms, earthquakes, ice) recognize and integrate these uncertainties into loading characterizations in different ways.

Bea, R.G. (Univ. of California, Berkeley, CA (United States). Dept. of Civil Engineering)

1993-11-01

194

Evidence for the role of environmental agents in the initiation or progression of autoimmune conditions.  

PubMed Central

The concordance of autoimmune disease among identical twins is virtually always less than 50% and often in the 25-40% range. This observation, as well as epidemic clustering of some autoimmune diseases following xenobiotic exposure, reinforces the thesis that autoimmune disease is secondary to both genetic and environmental factors. Because nonliving agents do not have genomes, disease characteristics involving nonliving xenobiotics are primarily secondary to host phenotype and function. In addition, because of individual genetic susceptibilities based not only on major histocompatibility complex differences but also on differences in toxin metabolism, lifestyles, and exposure rates, individuals will react differently to the same chemicals. With these comments in mind it is important to note that there have been associations of a number of xenobiotics with human autoimmune disease, including mercury, iodine, vinyl chloride, canavanine, organic solvents, silica, l-tryptophan, particulates, ultraviolet radiation, and ozone. In addition, there is discussion in the literature that raises the possibility that xenobiotics may also exacerbate an existing autoimmune disease. In this article we discuss these issues and, in particular, the evidence for the role of environmental agents in the initiation or progression of autoimmune conditions. With the worldwide deterioration of the environment, this is a particularly important subject for human health.

Powell, J J; Van de Water, J; Gershwin, M E

1999-01-01

195

Changes in fatty acid and hydrocarbon composition of zooplankton assemblages related to environmental conditions  

SciTech Connect

Changes in zooplankton fatty acid and hydrocarbon patterns are described in relation to changes in environmental conditions and species composition. The regulation of zooplankton abundance by sea nettle-ctenophore interaction was examined in a small Rhode Island coastal pond. Sea nettles were nettles were able to eliminate ctenophores from the pond and subsequently zooplankton abundance increased. During one increase in zooplankton abundance, it was found that polyunsaturated fatty acids decreased while monounsaturated fatty acids increased. It was concluded that this shift in biochemical pattern was due to food limitation. In addition, zooplankton fatty acids were used in multivariate discriminant analysis to classify whether zooplankton were from coastal or estuarine environments. Zooplankton from coastal environments were characterized by higher monounsaturate fatty acids. Zooplankton hydrocarbon composition was affected by species composition and by pollution inputs. The presence of Calanus finmarchicus was detected by increased levels of pristane.

Lambert, R.M.

1989-01-01

196

Revegetation processes and environmental conditions in abandoned peat production fields in Estonia  

NASA Astrophysics Data System (ADS)

As a result of peat extraction, peat production has been finished in Estonia at different times in 154 peat production areas and 9,500 ha (~1% of peatlands) are abandoned, although the peat reserves are not exhausted yet; besides, several areas are not properly recultivated. In addition 12,000 ha of fens (oligotrophic peat layers) are drained and used as grasslands. If the abandoned and non-recultivated peat production areas are not vegetated, their CO2 emission is considerable and peat mineralises in such areas. The aim of the study was to find out specific ecological and geological factors, which affect recovering of peatlands and influence the recultivation. During the revision the amount and quality of the remained reserves, as well as the state of water regime, drainage network and revegetation was assessed in all 154 abandoned peat production areas. The study showed that the state of them is very variable. Some of them are covered with forest, prevailingly with birches at former drainage ditches, later supplemented by pine trees. In the others predominate grasses among plants, and various species of moss (Cladonia rei, Bryum caespiticum, Sphagnum ripariuma, Sphagnum squarrosum) occur as well. Besides, some abandoned areas are completely overgrown with cotton grass. Open abandoned peat areas, which are not covered by vegetation, are much rarer. We found out, that water regime among the factors plays most important role. Moreover abandoned peat production fields, where the environmental conditions have changed - are appropriate for growth of several moss species, which cannot inhabit the areas already occupied by other species. The most interesting discovers were: second growing site of Polia elongata in West-Estonia and Ephemerum serratum, last found in Estonia in the middle of the 19th century, was identified in central Estonia. Also Campylopus introflexus, what was unknown in Estonia. However, the changes in environmental conditions influence the peat layers structure and technical characteristics of organic soils that affect the vegetation of peatlands.

Orru, M.; Orru, H.

2009-04-01

197

Explorative Multifactor Approach for Investigating Global Survival Mechanisms of Campylobacter jejuni under Environmental Conditions  

PubMed Central

Explorative approaches such as DNA microarray experiments are becoming increasingly important in microbial research. Despite these major technical advancements, approaches to study multifactor experiments are still lacking. We have addressed this problem by using rotation testing and a novel multivariate analysis of variance (MANOVA) approach (50-50 MANOVA) to investigate interacting experimental factors in a complex experimental design. Furthermore, a new rotation testing based method was introduced to calculate false-discovery rates for each response. This novel analytical concept was used to investigate global survival mechanisms in the environment of the major food-borne pathogen C. jejuni. We simulated nongrowth environmental conditions by investigating combinations of the factors temperature (5 and 25°C) and oxygen tension (anaerobic, microaerobic, and aerobic). Data were generated with DNA microarrays for information about gene expression patterns and Fourier transform infrared (FT-IR) spectroscopy to study global macromolecular changes in the cell. Microarray analyses showed that most genes were either unchanged or down regulated compared to the reference (day 0) for the conditions tested and that the 25°C anaerobic condition gave the most distinct expression pattern with the fewest genes expressed. The few up-regulated genes were generally stress related and/or related to the cell envelope. We found, using FT-IR spectroscopy, that the amount of polysaccharides and oligosaccharides increased under the nongrowth survival conditions. Potential mechanisms for survival could be to down regulate most functions to save energy and to produce polysaccharides and oligosaccharides for protection against harsh environments. Basic knowledge about the survival mechanisms is of fundamental importance in preventing transmission of this bacterium through the food chain.

Moen, Birgitte; Oust, Astrid; Langsrud, ?yvind; Dorrell, Nick; Marsden, Gemma L.; Hinds, Jason; Kohler, Achim; Wren, Brendan W.; Rudi, Knut

2005-01-01

198

Stability of Metabolic Correlations under Changing Environmental Conditions in Escherichia coli - A Systems Approach  

PubMed Central

Background Biological systems adapt to changing environments by reorganizing their cellular and physiological program with metabolites representing one important response level. Different stresses lead to both conserved and specific responses on the metabolite level which should be reflected in the underlying metabolic network. Methodology/Principal Findings Starting from experimental data obtained by a GC-MS based high-throughput metabolic profiling technology we here develop an approach that: (1) extracts network representations from metabolic condition-dependent data by using pairwise correlations, (2) determines the sets of stable and condition-dependent correlations based on a combination of statistical significance and homogeneity tests, and (3) can identify metabolites related to the stress response, which goes beyond simple observations about the changes of metabolic concentrations. The approach was tested with Escherichia coli as a model organism observed under four different environmental stress conditions (cold stress, heat stress, oxidative stress, lactose diauxie) and control unperturbed conditions. By constructing the stable network component, which displays a scale free topology and small-world characteristics, we demonstrated that: (1) metabolite hubs in this reconstructed correlation networks are significantly enriched for those contained in biochemical networks such as EcoCyc, (2) particular components of the stable network are enriched for functionally related biochemical pathways, and (3) independently of the response scale, based on their importance in the reorganization of the correlation network a set of metabolites can be identified which represent hypothetical candidates for adjusting to a stress-specific response. Conclusions/Significance Network-based tools allowed the identification of stress-dependent and general metabolic correlation networks. This correlation-network-based approach does not rely on major changes in concentration to identify metabolites important for stress adaptation, but rather on the changes in network properties with respect to metabolites. This should represent a useful complementary technique in addition to more classical approaches.

Nikoloski, Zoran; Selbig, Joachim; Nikiforova, Victoria; Catchpole, Gareth; Willmitzer, Lothar

2009-01-01

199

Male-killing endosymbionts: influence of environmental conditions on persistence of host metapopulation  

PubMed Central

Background Male killing endosymbionts manipulate their arthropod host reproduction by only allowing female embryos to develop into infected females and killing all male offspring. Because of the reproductive manipulation, we expect them to have an effect on the evolution of host dispersal rates. In addition, male killing endosymbionts are expected to approach fixation when fitness of infected individuals is larger than that of uninfected ones and when transmission from mother to offspring is nearly perfect. They then vanish as the host population crashes. High observed infection rates and among-population variation in natural systems can consequently not be explained if defense mechanisms are absent and when transmission efficiency is perfect. Results By simulating the host-endosymbiont dynamics in an individual-based metapopulation model we show that male killing endosymbionts increase host dispersal rates. No fitness compensations were built into the model for male killing endosymbionts, but they spread as a group beneficial trait. Host and parasite populations face extinction under panmictic conditions, i.e. conditions that favor the evolution of high dispersal in hosts. On the other hand, deterministic 'curing' (only parasite goes extinct) can occur under conditions of low dispersal, e.g. under low environmental stochasticity and high dispersal mortality. However, high and stable infection rates can be maintained in metapopulations over a considerable spectrum of conditions favoring intermediate levels of dispersal in the host. Conclusion Male killing endosymbionts without explicit fitness compensation spread as a group selected trait into a metapopulation. Emergent feedbacks through increased evolutionary stable dispersal rates provide an alternative explanation for both, the high male-killing endosymbiont infection rates and the high among-population variation in local infection rates reported for some natural systems.

2008-01-01

200

Separating predictable and unpredictable work to manage interruptions and promote safe and effective work flow.  

PubMed

Predictable and unpredictable patient care tasks compete for caregiver time and attention, making it difficult for patient care staff to reliably and consistently meet patient needs. We have piloted a redesigned care model that separates the work of patient care technicians based on task predictability and creates role specificity. This care model shows promise in improving the ability of staff to reliably complete tasks in a more consistent and timely manner. PMID:22036831

Kowinsky, Amy M; Shovel, Judith; McLaughlin, Maribeth; Vertacnik, Lisa; Greenhouse, Pamela K; Martin, Susan Christie; Minnier, Tamra E

201

From Unpredictability to Indistinguishability: A Simple Construction of PseudoRandom Functions from MACs (Extended Abstract)  

Microsoft Academic Search

This paper studies the relationship between unpredictable functions (which formalize the concept of a MAC) and pseudo-random functions. We show an efficient transformation of the former to\\u000a the latter using a unique application of the Goldreich-Levin hard-core bit (taking the inner-product with a random vector\\u000a r): While in most applications of the GL-bit the random vector r may be public,

Moni Naor; Omer Reingold

1998-01-01

202

Evaluating Security Properties of Architectures in Unpredictable Environments: A Case for Cloud  

Microsoft Academic Search

The continuous evolution and unpredictability underlying service-based systems leads to difficulties in making exact QoS claims about the dependability of architectures interfacing with them. Hence, there is a growing need for new methods to evaluate the dependability of architectures inter- facing with such environments. This paper presents a method for evaluating the security quality attribute of architectures in service-based systems.

Funmilade Faniyi; Rami Bahsoon; Andy Evans; Rick Kazman

2011-01-01

203

Choice of optimal oviposition sites by Hoplobatrachus occipitalis (Anura: Ranidae) in an unpredictable and patchy environment  

Microsoft Academic Search

The rock pools on the river bank of the Como National Park (West Africa) provide a very diverse and unpredictable environment\\u000a for anuran larval development. Because rock pools differ considerably in biotic and abiotic parameters, it should be adaptive\\u000a for reproducing anurans to choose the most suitable oviposition sites. During the beginning of each rainy season (March to\\u000a May), from

M. Spieler; K. E. Linsenmair

1997-01-01

204

Effects of Local Environmental-Conditions on Nestling Growth in the Great Tit Parus-Major L  

Microsoft Academic Search

Daily weight increments of nestling Great Tits are expressed as ratios of observed increment divided by the increment expected under favourable conditions. We used this ratio to examine the effects of local environmental conditions on nestling growth. We demonstrate a positive relationship between nestling growth and food availability at that time and location. This relationship is stronger with the maximum

L. F. Keller; A. J. Van Noordwijk

1994-01-01

205

Rate constants and mechanisms for the crystallization of Al nano-goethite under environmentally relevant conditions  

NASA Astrophysics Data System (ADS)

Mobile inorganic and organic nanocolloidal particles originate-from and interact-with bulk solid phases in soil and sediment environments, and as such, they contribute to the dynamic properties of environmental systems. In particular, ferrihydrite and (nano)goethite are the most abundant of nanocolloidal Fe oxy(hydr)oxides in these environments. We therefore investigated the ferrihydrite to goethite phase transformation using experimental reaction conditions that mimicked environmental conditions where the formation of nanocolloidal Fe oxy(hydr)oxides may occur: slow titration of dilute solutions to pH 5 at 25 °C with and without 2 mol% Al. Subsequently, the rate constants from 54-d nano-goethite aging/crystallization experiments at 50 °C were determined using aliquots pulled for vibrational spectroscopy (including multivariate curve resolution, MCR, analyses of infrared spectra) and synchrotron-based X-ray diffraction (XRD). We also present a mechanistic model that accounts for the nano-goethite crystallization observed by the aforementioned techniques, and particle structural characteristics observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). In contrast to the common assumption that metastable ferrihydrite precipitates first, before it transforms to goethite, the presence of characteristic infrared bands in freshly synthesized nanoparticle suspensions indicate goethite can precipitate directly from solution under environmentally relevant conditions: low Fe concentration, ambient temperature, and pH maintained at 5. However, the presence of 2 mol% Al prevented direct goethite precipitation. Rate constants obtained by fitting the contributions from the MCR-derived goethite-like component to the OH-stretching region were (7.4 ± 1.1) × 10-7 s-1 for 0% Al and (4.2 ± 0.4) × 10-7 s-1 for 2 mol% Al suspensions. Rate constants derived from intensities of OH-bending infrared vibrations (795 and 895 cm-1) showed similar values, within error, for both 0 and 2 mol% Al nanoparticle suspensions. Thus, the presence of 2 mol% Al decreased the rate constants determined from analyses of infrared OH-stretching and OH-bending vibrations by 43-57%. We postulate that dissolution re-precipitation reactions are accelerated in aggregate microenvironments by locally increased supersaturation, yielding the dominant mechanism for transformation of ferrihydrite to goethite and goethite crystal growth when bulk ion concentrations are low. Although we did observe growth of a population of prismatic goethite single crystals by TEM, there was more substantial growth of a population of polycrystalline goethite needles that appeared to retain some defects from a preceding aggregation step that we detected with DLS. Since the presence of Al hinders the dissolution of ferrihydrite, it too reduces the rate of crystallization to goethite and its crystal growth. As exemplified in this nano-particle crystallization study, the combination of advanced spectral-curve-resolution algorithms and sensitive and quantitative infrared sampling techniques opens future opportunities for the quantification of mineral phase dynamics in nanocolloidal suspensions, which is important for many aspects of environmental studies.

Bazilevskaya, Ekaterina; Archibald, Douglas D.; Martínez, Carmen Enid

2012-07-01

206

Ten-year variability in fluxes, meteorology, and environmental conditions at a Colorado subalpine forest site  

NASA Astrophysics Data System (ADS)

Changing meteorological and environmental conditions affect fluxes; model analysis has shown that environmental variability directly accounts for about half the interannual variability in net ecosystem exchange (NEE) of CO2 whereas the other 50% is due to biotic responses to these changing variables (Richardson et al. 2007). In our study, ten years (1998-2008) of turbulent flux measurements of heat, water vapor, and CO2 at the Niwot Ridge AmeriFlux site (Monson et al. 2002) are examined with respect to meteorological conditions (atmospheric temperature, stability, precipitation, and cloudiness) as well as changes in environmental conditions, such as snow depth and soil moisture. The typical yearly cycle and an estimate of the magnitude of year-to-year variability in the diurnal fluxes and other variables for a high-elevation subalpine forest ecosystem are presented. Wintertime ecosystem respiration has an average 30-min NEE of 0.62 ?mol m-2 s-1 with an interannual range between 0.5-1 ?mol m-2 s-1. Uptake of CO2 in late summer has an average NEE of -0.71 ?mol m-2 s-1 with an interannual range between -0.1 to -1.5 ?mol m-2 s-1. Previous studies at the Niwot Ridge AmeriFlux site have described the importance of photosynthetic photon flux density (PPFD) (Monson et al. 2002) and also growing season length (Hu et al. 2009) on NEE. Water isotope ratios analyzed by Hu et al. (2009) have shown that trees at the site primarily rely on water from snowmelt to sustain them throughout the summer; combining this result with the SIPNET model, Hu et al. conclude that there is a limited connection between summer precipitation and the cumulative annual gross primary production (GPP). We have tested this conclusion more explicitly by examining the response of NEE to specific precipitation events and the effect of extended dry periods on the diel cycle of the fluxes, CO2 mole fraction, sap flow, and other meteorological and soil variables. Additionally, we examine the connection between seasonal changes in NEE to changes in CO2 mole fraction measured with a tunable diode laser at the site (Schaeffer et al. 2008). References: Hu, J., et al., 2009: Longer growing seasons lead to less carbon sequestration by a subalpine forest. Global Change Biology, doi:10.1111/j.1365-2486.2009.01967.x Monson, R. K., et al., 2002: Carbon sequestration in a high-elevation, subalpine forest. Global Change Biology, 8, 459-478. Richardson, A.D., et al., 2007: Environmental variation is directly responsible for short- but not long-term variation in forest-atmosphere carbon exchange. Global Change Biology, 13, 788-803. Schaeffer, S.M., et al., 2008: Long-term field performance of a tunable diode laser absorption spectrometer for analysis of carbon isotopes of CO2 in forest air. Atmospheric Chemistry and Physics, 8, 5263-5277.

Burns, S. P.; Turnipseed, A.; Bowling, D. R.; Hu, J.; Monson, R. K.

2009-12-01

207

[Significance of motivation balance for a choice of dog's behavior under conditions of environmental uncertainty].  

PubMed

Two experimental models with a choice between two reinforcements were used for assessment of individual typological features of dogs. In the first model dogs were given the choice of homogeneous food reinforcements: between less valuable constantly delivered reinforcement and more valuable reinforcement but delivered with low probabilities. In the second model the dogs had the choice of heterogeneous reinforcements: between performing alimentary and defensive reactions. Under conditions of rise of uncertainty owing to a decrease in probability of getting the valuable food, two dogs continued to prefer the valuable reinforcement, while the third animal gradually shifted its behavior from the choice of a highly valuable but infrequent reward to a less valuable but easily achieved reinforcement. Under condition of choice between the valuable food reinforcement and avoidance of electrocutaneous stimulation, the first two dogs preferred food, whereas the third animal which had been previously oriented to the choice of the low-valuable constant reinforcement, steadily preferred the avoidance behavior. The data obtained are consistent with the hypothesis according to which the individual typological characteristics of animals's (human's) behavior substantially depend on two parameters: extent of environmental uncertainty and subjective features of reinforcement assessment. PMID:17642372

Chilingarian, L I; Grigor'ian, G A

208

Controlled particle removal from surfaces by electrodynamic methods for terrestrial, lunar, and Martian environmental conditions  

NASA Astrophysics Data System (ADS)

An Electrodynamic Dust Shield to remove already deposited micron-size particles from surfaces and to prevent the accumulation of such particles on surfaces has been developed. In addition to terrestrial application, our NASA laboratory is adapting this technology for the dusty and harsh environments of the Moon and Mars. The Apollo missions to the moon showed that lunar dust can hamper astronaut surface activities due to its ability to cling to most surfaces. NASA's Mars exploration landers and rovers have also shown that the problem is equally hard if not harder on Mars. In this paper, we show that an appropriate design can prevent the electrostatic breakdown at the low Martian atmospheric pressures. We are also able to show that uncharged dust can be lifted and removed from surfaces under simulated Martian environmental conditions. This technology has many potential benefits for removing dust from visors, viewports and many other surfaces as well as from solar arrays. We have also been able to develop a version of the electrodynamic dust shield working under hard vacuum conditions. This version should work well on the moon. We present data on the design and optimization of both types of dust shields as well substantial data on the clearing factors for transparent dust shields designed to protect solar panels for Martian exploration.

Calle, C. I.; Mazumder, M. K.; Immer, C. D.; Buhler, C. R.; Clements, J. S.; Lundeen, P.; Chen, A.; Mantovani, J. G.

2008-12-01

209

A nanofluidic device for single molecule studies with in situ control of environmental solution conditions.  

PubMed

We report an approach to study the in situ conformational response of single biomolecules such as DNA to a change in environmental solution conditions. These conditions are, for example, the composition of the buffer or the presence of protein. For this purpose, we designed and fabricated a nanofluidic device featuring two arrays of parallel nanochannels in a perpendicular configuration. The cross-sections of the channels are rectangular with a diameter down to 175 nm. These lab-on-a-chip devices were made of polydimethylsiloxane (PDMS) cast on a high quality master stamp, obtained by proton beam writing and UV lithography. Biomolecules can be inserted into the device through the array of channels in one direction, whereas the buffer can be exchanged through the intersecting array of channels in the other direction. A buffer exchange time inside the grid of nanochannels of less than one second was measured by monitoring the conductivity of salt solutions. The exchange time of a protein was typically a few seconds, as determined by imaging the influx of fluorescence labelled protamine. We demonstrate the functionality of the device by investigating the compaction of DNA by protamine and the unpacking of pre-compacted DNA through an increase in the concentration of salt. PMID:23674166

Zhang, Ce; Jiang, Kai; Liu, Fan; Doyle, Patrick S; van Kan, Jeroen A; van der Maarel, Johan R C

2013-07-21

210

Correlating bilayer tablet delamination tendencies to micro-environmental thermodynamic conditions during pan coating.  

PubMed

Abstract Objective: The objective of this study was to determine the impact that the micro-environment, as measured by PyroButton data loggers, experienced by tablets during the pan coating unit operation had on the layer adhesion of bilayer tablets in open storage conditions. Materials and methods: A full factorial design of experiments (DOE) with three center points was conducted to study the impact of final tablet hardness, film coating spray rate and film coating exhaust temperature on the delamination tendencies of bilayer tablets. PyroButton data loggers were placed (fixed) at various locations in a pan coater and were also allowed to freely move with the tablet bed to measure the micro-environmental temperature and humidity conditions of the tablet bed. Results: The variance in the measured micro-environment via PyroButton data loggers accounted for 75% of the variance in the delamination tendencies of bilayer tablets on storage (R(2?)=?0.75). A survival analysis suggested that tablet hardness and coating spray rate significantly impacted the delamination tendencies of the bilayer tablets under open storage conditions. The coating exhaust temperature did not show good correlation with the tablets' propensity to crack indicating that it was not representative of the coating micro-environment. Models created using data obtained from the PyroButton data loggers outperformed models created using primary DOE factors in the prediction of bilayer tablet strength, especially upon equipment or scale transfers. Conclusion: The coating micro-environment experienced by tablets during the pan coating unit operation significantly impacts the strength of the bilayer interface of tablets on storage. PMID:23638984

Zacour, Brian M; Pandey, Preetanshu; Subramanian, Ganeshkumar; Gao, Julia Z; Nikfar, Faranak

2013-05-01

211

Effects of nutritional and environmental conditions on Salmonella sp. biofilm formation.  

PubMed

Biofilm formation on food industry surfaces has important health and economic consequences, since they can serve as a potential source of contamination for food products, which may lead to food spoilage or transmission of diseases. Salmonella sp. is one of the most important foodborne pathogens and several studies have led to the discovery that these bacteria are capable of adhering and forming biofilms on different surfaces. The attachment of bacterial cells is affected by several factors, including the medium in which they are grown, motility, growth phase of the cells, type and properties of the inert material, presence of organic material, temperature, pH, contact time, and so on. This investigation focused on the study and quantification of the effects of temperature (20 to 40 °C), pH (4.5 to 7.5), and medium composition (0.5 to 2.5 g/L of peptone) on biofilm formation by Salmonella sp. on stainless steel through surface response modeling. Results highlighted that the target strain was able to adhere on stainless steel, under all the conditions tested. To assess potential differences, the aptitude to biofilm formation (ABF), defined as the time necessary to start adhesion on the surface, was calculated by using the Gompertz equation. This parameter was modeled through a stepwise regression procedure and experimental conditions resulting in the greater ABF were growth in poor media (1.0 to 1.5 g/L of peptone), incubation temperature of about 30 °C, pH close to 6.0. Practical Application: The importance of this work lies in its extension of our knowledge about the effect of different environmental conditions on Salmonella adherence to stainless steel food-processing equipment, as a better understanding of biofilms may provide valuable pathways for the prevention of biofilm formation. PMID:21535687

Speranza, Barbara; Corbo, Maria Rosaria; Sinigaglia, Milena

2010-12-08

212

Scale-specific determinants of a mixed beech and oak seedling–sapling bank under different environmental and biotic conditions  

Microsoft Academic Search

The persistence of seedlings in the forest understorey is of major importance for the maintenance and regeneration of canopy\\u000a trees in several forested ecosystems. In the present study, we examine the small-scale spatial pattern of a mixed beech and\\u000a oak seedling–sapling bank in two areas of an unmanaged temperate deciduous forest with different environmental conditions.\\u000a We used environmental, biotic and

Antonio Gazol; Ricardo Ibáñez

2010-01-01

213

Environmental conditions influence egg color of reed warblers Acrocephalus scirpaceus and their parasite, the common cuckoo Cuculus canorus  

Microsoft Academic Search

The outer layer of the eggshell in birds is in many cases covered by pigments that are assumed to be genetically determined\\u000a traits with a negligible environmental component. To test the hypothesis that spring environmental conditions (i.e., temperature\\u000a and rainfall) may affect bird egg pigmentation, we measured by spectrophotometry and photography egg coloration and spottiness\\u000a on reed warbler (Acrocephalus scirpaceus

Jesús M. Avilés; Bård G. Stokke; Arne Moksnes; Eivin Røskaft; Anders P. Møller

2007-01-01

214

33 CFR 148.710 - What environmental conditions must be satisfied?  

Code of Federal Regulations, 2013 CFR

...technology to prevent or minimize adverse impacts on the marine environment (33 U.S.C...in the preparation of a single detailed environmental impact statement or environmental assessment for all timely applications covering a...

2013-07-01

215

Environmental Market Conditions and Business Opportunities in Key Latin American Countries. Business Focus Series.  

National Technical Information Service (NTIS)

Environmental markets and U.S. business opportunities in six Latin American countries -- Argentina, Brazil, Chile, Colombia, Mexico, and Venezuela -- are reviewed in the report. Specific issues covered include environmental policy, the current and prospec...

1993-01-01

216

EMAP AND OTHER TOOLS FOR MEASURING BIODIVERSITY HABITAT CONDITIONS AND ENVIRONMENTAL TRENDS  

EPA Science Inventory

Several research efforts that will contribute to assessment and monitoring of neotropical migratory birds are described, including: ) the use of neotropical migrants in the Environmental Monitoring and Assessment Program (EMAP) as potential indicators of general environmental con...

217

Developmental programming: Cumulative effects of increased pre-hatching corticosterone levels and post-hatching unpredictable food availability on physiology and behaviour in adulthood?  

PubMed Central

Prolonged exposure to stress during development can have long-term detrimental effects on health and wellbeing. However, the environmental matching hypothesis proposes that developmental stress programs physiology and behaviour in an adaptive way that can enhance fitness if early environments match those experienced later in life. Most research has focused on the harmful effects that stress during a single period in early life may exert in adulthood. In this study, we tested the potential additive and beneficial effects that stress experienced during both pre- and post-hatching development may have on adult physiology and behaviour. Japanese quail experienced different stress-related treatments across two developmental life stages: pre-hatching corticosterone (CORT) injection, post-hatching unpredictable food availability, both pre- and post-hatching treatments, or control. In adulthood, we determined quails' acute stress response, neophobia and novel environment exploration. The pre-hatching CORT treatment resulted in attenuated physiological responses to an acute stressor, increased activity levels and exploration in a novel environment. Post-hatching unpredictable food availability decreased adults' latency to feed. Furthermore, there were cumulative effects of these treatments across the two developmental stages: quail subjected to both pre- and post-hatching treatments were the most explorative and risk-taking of all treatment groups. Such responses to novel environments could enhance survival in unpredictable environments in later life. Our data also suggest that these behavioural responses may have been mediated by long-term physiological programming of the adrenocortical stress response, creating phenotypes that could exhibit fitness-enhancing behaviours in a changing environment.

Zimmer, Cedric; Boogert, Neeltje J.; Spencer, Karen A.

2013-01-01

218

Developmental programming: Cumulative effects of increased pre-hatching corticosterone levels and post-hatching unpredictable food availability on physiology and behaviour in adulthood.  

PubMed

Prolonged exposure to stress during development can have long-term detrimental effects on health and wellbeing. However, the environmental matching hypothesis proposes that developmental stress programs physiology and behaviour in an adaptive way that can enhance fitness if early environments match those experienced later in life. Most research has focused on the harmful effects that stress during a single period in early life may exert in adulthood. In this study, we tested the potential additive and beneficial effects that stress experienced during both pre- and post-hatching development may have on adult physiology and behaviour. Japanese quail experienced different stress-related treatments across two developmental life stages: pre-hatching corticosterone (CORT) injection, post-hatching unpredictable food availability, both pre- and post-hatching treatments, or control. In adulthood, we determined quails' acute stress response, neophobia and novel environment exploration. The pre-hatching CORT treatment resulted in attenuated physiological responses to an acute stressor, increased activity levels and exploration in a novel environment. Post-hatching unpredictable food availability decreased adults' latency to feed. Furthermore, there were cumulative effects of these treatments across the two developmental stages: quail subjected to both pre- and post-hatching treatments were the most explorative and risk-taking of all treatment groups. Such responses to novel environments could enhance survival in unpredictable environments in later life. Our data also suggest that these behavioural responses may have been mediated by long-term physiological programming of the adrenocortical stress response, creating phenotypes that could exhibit fitness-enhancing behaviours in a changing environment. PMID:23891687

Zimmer, Cédric; Boogert, Neeltje J; Spencer, Karen A

2013-07-26

219

Exposure to environmental tobacco smoke: association with personal characteristics and self reported health conditions  

PubMed Central

STUDY OBJECTIVE—To examine the association between exposure to environmental tobacco smoke (ETS) and demographic, lifestyle, occupational characteristics and self reported health conditions.?DESIGN—Cross sectional study, using data from multiphasic health checkups between 1979 and 1985.?SETTING—Large health plan in Northern California, USA.?PARTICIPANTS—16 524 men aged 15-89 years and 26 197 women aged 15-105 years who never smoked.?RESULTS—Sixty eight per cent of men and 64 per cent of women reported any current ETS exposure (at home, in small spaces other than home or in large indoor areas). The exposure time from all three sources of ETS exposure correlated negatively with age. Men and women reporting high level ETS exposure were more likely to be black and never married or separated/divorced, to have no college or partial college education, to consume three alcoholic drink/day or more and to report exposure to several occupational hazards. Consistent independent relations across sexes were found between any current exposure to ETS and a positive history of hay fever/asthma (odds ratio (OR)=1.22 in men, 1.14 in women), hearing loss (OR=1.30 in men, 1.27 in women), severe headache (OR=1.22 in men, 1.17 in women), and cold/flu symptoms (OR=1.52 in men, 1.57 in women). Any current ETS exposure was also associated with chronic cough (OR=1.22) in men and with heart disease (OR=1.10) in women. Self reported stroke was inversely associated with any current ETS exposure in men (OR=0.27). No associations were noted for cancer or tumour and for migraine.?CONCLUSION—ETS exposure correlated with several personal characteristics potentially associated with adverse health outcomes. Although the study design precluded causal inference, ETS exposure was associated with several self reported acute and chronic medical conditions.???Keywords: environmental tobacco smoke; smoking

Iribarren, C; Friedman, G; Klatsky, A; Eisner, M

2001-01-01

220

Effect of environmental conditions on the spectroscopic signature of DNT in sand  

NASA Astrophysics Data System (ADS)

Landmines have been a part of war technology for many years. As a result of the continued and indiscriminate use in approximately 90 countries landmines pose a severe and ever growing problem and a daily risk. Raman Spectroscopy is capable of providing rich information about the molecular structure of the sample and pinpoint detection of many chemicals, both of organic and inorganic nature. The presence of landmines in soils can be detected by Raman Spectroscopy sensing in a Point Detection modality, using characteristic vibrational signals of each explosive present in landmines. Detection of 2,4-DNT in sand and studies on how the vibrational signatures of 2,4-DNT is modified by interacting with soil particles and environmental conditions is reported. Raman Microspectrometers equipped with 514 nm and 785 nm laser excitation lines were used. The work focused in how the spectroscopic signatures of DNT in contact with Ottawa Sand are affected by the presence of humidity, pH, temperature, UV light and reaction times. Samples of mixtures of sand/2,4-DNT were analyzed by Raman Spectroscopy at 10, 50 and 100% water content and temperatures in range of 40-80 °C. Mixtures were also analyzed at different pH: 4, 7 and 10 and under ultraviolet light at 254 nm. Raman spectra were taken as a function of time in an interval from 24 to 336 hours (two weeks). Characteristic signals of 2,4-DNT were analyzed in different ranges 100-3800 cm-1, 600-1200 cm-1, 300-1700 cm-1 and 2800-3500 cm-1. The effect of these variables was measured during 45 consecutive days. It was confirmed that the decrease of characteristic vibrational signatures of 2,4-DNT can be attributed to increase of the degradation of 2,4-DNT by the simulated environmental conditions. Spectroscopic characterization of degradation products, both in contact with sand as well as airborne is under way. These results will make possible the development of highly sensitive sensors for detection of explosives materials and correlated with their degradation products in landmines.

Blanco, Alejandro; Mina, Nairmen; Castro, Miguel E.; Castillo-Chara, Jairo; Hernandez-Rivera, Samuel P.

2005-06-01

221

Simulation of the environmental climate conditions on martian surface and its effect on Deinococcus radiodurans  

NASA Astrophysics Data System (ADS)

The resistance of terrestrial microorganisms under the thermo-physical conditions of Mars (diurnal temperature variations, UV climate, atmospheric pressure and gas composition) at mid-latitudes was studied for the understanding and assessment of potential life processes on Mars. In order to accomplish a targeted search for life on other planets, e.g. Mars, it is necessary to know the limiting physical and chemical parameters of terrestrial life. Therefore the polyextremophile bacterium Deinococcus radiodurans was chosen as test organism for these investigations. For the simulation studies at the Planetary and Space Simulation Facilities (PSI) at DLR, Cologne, Germany, conditions that are present during the southern summer at latitude of 60° on Mars were applied. We could simulate several environmental parameters of Mars in one single experiment: vacuum/low pressure, anoxic atmosphere and diurnal cycles in temperature and relative humidity, energy-rich ultraviolet (UV) radiation as well as shielding by different martian soil analogue materials. These parameters have been applied both single and in different combinations in laboratory experiments. Astonishingly the diurnal Mars-like cycles in temperature and relative humidity affected the viability of D. radiodurans cells quite severely. But the martian UV climate turned out to be the most deleterious factor, though D. radiodurans is red-pigmented due to carotenoids incorporated in its cell wall, which have been assigned not only a possible role as free radical scavenger but also as a UV-protectant. An additional UV-protection was accomplished by mixing the bacteria with nano-sized hematite.

de La Vega, U. Pogoda; Rettberg, P.; Reitz, G.

222

Influence of Environmental Conditions on Methanogenic Compositions in Anaerobic Biogas Reactors  

PubMed Central

The influence of environmental parameters on the diversity of methanogenic communities in 15 full-scale biogas plants operating under different conditions with either manure or sludge as feedstock was studied. Fluorescence in situ hybridization was used to identify dominant methanogenic members of the Archaea in the reactor samples; enriched and pure cultures were used to support the in situ identification. Dominance could be identified by a positive response by more than 90% of the total members of the Archaea to a specific group- or order-level probe. There was a clear dichotomy between the manure digesters and the sludge digesters. The manure digesters contained high levels of ammonia and of volatile fatty acids (VFA) and were dominated by members of the Methanosarcinaceae, while the sludge digesters contained low levels of ammonia and of VFA and were dominated by members of the Methanosaetaceae. The methanogenic diversity was greater in reactors operating under mesophilic temperatures. The impact of the original inoculum used for the reactor start-up was also investigated by assessment of the present population in the reactor. The inoculum population appeared to have no influence on the eventual population.

Karakashev, Dimitar; Batstone, Damien J.; Angelidaki, Irini

2005-01-01

223

Natal dispersal driven by environmental conditions interacting across the annual cycle of a migratory songbird  

PubMed Central

Natal dispersal, the process through which immature individuals permanently depart their natal area in search of new sites, is integral to the ecology and evolution of animals. Insights about the underlying causes of natal dispersal arise mainly from research on species whose short dispersal distances or restricted distributions make them relatively easy to track. However, for small migratory animals, the causes of natal dispersal remain poorly understood because individuals are nearly impossible to track by using conventional mark–recapture approaches. Using stable-hydrogen isotope ratios in feathers of American redstarts (Setophaga ruticilla) captured as immature birds and again as adults, we show that habitat use during the first tropical nonbreeding season appears to interact with latitudinal gradients in spring phenology on the temperate breeding grounds to influence the distance traveled on the initial spring migration and the direction of natal dispersal. In contrast, adult redstarts showed considerable site fidelity between breeding seasons, indicating that environmental conditions did not affect dispersal patterns after the first breeding attempt. Our findings suggest that habitat occupancy during the first nonbreeding season helps determine the latitude at which this species of Neotropical–Nearctic migratory bird breeds throughout its life and emphasize the need to understand how events throughout the annual cycle interact to shape fundamental biological processes.

Studds, Colin E.; Kyser, T. Kurt; Marra, Peter P.

2008-01-01

224

Modelling stream-fish functional traits in reference conditions: regional and local environmental correlates.  

PubMed

Identifying the environmental gradients that control the functional structure of biological assemblages in reference conditions is fundamental to help river management and predict the consequences of anthropogenic stressors. Fish metrics (density of ecological guilds, and species richness) from 117 least disturbed stream reaches in several western Iberia river basins were modelled with generalized linear models in order to investigate the importance of regional- and local-scale abiotic gradients to variation in functional structure of fish assemblages. Functional patterns were primarily associated with regional features, such as catchment elevation and slope, rainfall, and drainage area. Spatial variations of fish guilds were thus associated with broad geographic gradients, showing (1) pronounced latitudinal patterns, affected mainly by climatic factors and topography, or (2) at the basin level, strong upstream-downstream patterns related to stream position in the longitudinal gradient. Maximum native species richness was observed in midsize streams in accordance with the river continuum concept. The findings of our study emphasized the need to use a multi-scale approach in order to fully assess the factors that govern the functional organization of biotic assemblages in 'natural' streams, as well as to improve biomonitoring and restoration of fluvial ecosystems. PMID:23029242

Oliveira, João M; Segurado, Pedro; Santos, José M; Teixeira, Amílcar; Ferreira, Maria T; Cortes, Rui V

2012-09-24

225

Effects of environmental conditions on the release of phosphorus from biochar.  

PubMed

Biochar, the byproduct from fast pyrolysis of waste biomass, is widely used as a soil conditioner. The phosphorus in biochar is not only a P source for plant growth, but also an important factor caused the eutrophication of water. Here, the effects of environmental conditions on the release of different P species from biochar in a biochar-water system were investigated. About 2.2mgg(-1) P in the form of inorganic orthophosphate and pyrophosphate was released from a raw biochar (contained 4.7mg Pg(-1)) at initial pH of 9.0 in the initial 8h. The release of orthophosphate was significantly enhanced from 0.64 to 1.35mgg(-1) by the coexisting anions of Cl(-), NO3(-) or SO4(2-) due to the effect of ion exchange competition, while the release of pyrophosphate (P2O7(4-)) was not influenced by the introduction of anions which might be attributed to the formation of stable complexes. The introduction of Hoagland nutrient solution led to the decrease in release of P due to the formation of precipitates between dissolved P and excessive Ca(2+) and Mg(2+). PMID:23958443

Qian, Tingting; Zhang, Xuesong; Hu, Jianyang; Jiang, Hong

2013-08-16

226

Non-coding RNAs in marine Synechococcus and their regulation under environmentally relevant stress conditions.  

PubMed

Regulatory small RNAs (sRNAs) have crucial roles in the adaptive responses of bacteria to changes in the environment. Thus far, potential regulatory RNAs have been studied mainly in marine picocyanobacteria in genetically intractable Prochlorococcus, rendering their molecular analysis difficult. Synechococcus sp. WH7803 is a model cyanobacterium, representative of the picocyanobacteria from the mesotrophic areas of the ocean. Similar to the closely related Prochlorococcus it possesses a relatively streamlined genome and a small number of genes, but is genetically tractable. Here, a comparative genome analysis was performed for this and four additional marine Synechococcus to identify the suite of possible sRNAs and other RNA elements. Based on the prediction and on complementary microarray profiling, we have identified several known as well as 32 novel sRNAs. Some sRNAs overlap adjacent coding regions, for instance for the central photosynthetic gene psbA. Several of these novel sRNAs responded specifically to environmentally relevant stress conditions. Among them are six sRNAs changing their accumulation level under cold stress, six responding to high light and two to iron limitation. Target predictions suggested genes encoding components of the light-harvesting apparatus as targets of sRNAs originating from genomic islands and that one of the iron-regulated sRNAs might be a functional homolog of RyhB. These data suggest that marine Synechococcus mount adaptive responses to these different stresses involving regulatory sRNAs. PMID:22258101

Gierga, Gregor; Voss, Björn; Hess, Wolfgang R

2012-01-19

227

Non-coding RNAs in marine Synechococcus and their regulation under environmentally relevant stress conditions  

PubMed Central

Regulatory small RNAs (sRNAs) have crucial roles in the adaptive responses of bacteria to changes in the environment. Thus far, potential regulatory RNAs have been studied mainly in marine picocyanobacteria in genetically intractable Prochlorococcus, rendering their molecular analysis difficult. Synechococcus sp. WH7803 is a model cyanobacterium, representative of the picocyanobacteria from the mesotrophic areas of the ocean. Similar to the closely related Prochlorococcus it possesses a relatively streamlined genome and a small number of genes, but is genetically tractable. Here, a comparative genome analysis was performed for this and four additional marine Synechococcus to identify the suite of possible sRNAs and other RNA elements. Based on the prediction and on complementary microarray profiling, we have identified several known as well as 32 novel sRNAs. Some sRNAs overlap adjacent coding regions, for instance for the central photosynthetic gene psbA. Several of these novel sRNAs responded specifically to environmentally relevant stress conditions. Among them are six sRNAs changing their accumulation level under cold stress, six responding to high light and two to iron limitation. Target predictions suggested genes encoding components of the light-harvesting apparatus as targets of sRNAs originating from genomic islands and that one of the iron-regulated sRNAs might be a functional homolog of RyhB. These data suggest that marine Synechococcus mount adaptive responses to these different stresses involving regulatory sRNAs.

Gierga, Gregor; Voss, Bjorn; Hess, Wolfgang R

2012-01-01

228

Modelling Stream-Fish Functional Traits in Reference Conditions: Regional and Local Environmental Correlates  

PubMed Central

Identifying the environmental gradients that control the functional structure of biological assemblages in reference conditions is fundamental to help river management and predict the consequences of anthropogenic stressors. Fish metrics (density of ecological guilds, and species richness) from 117 least disturbed stream reaches in several western Iberia river basins were modelled with generalized linear models in order to investigate the importance of regional- and local-scale abiotic gradients to variation in functional structure of fish assemblages. Functional patterns were primarily associated with regional features, such as catchment elevation and slope, rainfall, and drainage area. Spatial variations of fish guilds were thus associated with broad geographic gradients, showing (1) pronounced latitudinal patterns, affected mainly by climatic factors and topography, or (2) at the basin level, strong upstream-downstream patterns related to stream position in the longitudinal gradient. Maximum native species richness was observed in midsize streams in accordance with the river continuum concept. The findings of our study emphasized the need to use a multi-scale approach in order to fully assess the factors that govern the functional organization of biotic assemblages in ‘natural’ streams, as well as to improve biomonitoring and restoration of fluvial ecosystems.

Oliveira, Joao M.; Segurado, Pedro; Santos, Jose M.; Teixeira, Amilcar; Ferreira, Maria T.; Cortes, Rui V.

2012-01-01

229

Effect of Plant Species and Environmental Conditions on Ice Nucleation Activity of Pseudomonas syringae on Leaves  

PubMed Central

Selected plant species and environmental conditions were investigated for their influences on expression of ice nucleation activity by 15 Pseudomonas syringae strains grown on plants in constant-temperature growth chamber studies. Ice nucleation frequencies (INFs), the fraction of cells that expressed ice nucleation at ?5 or ?9°C, of individual strains varied greatly, both on plants and in culture. This suggests that the probability of frost injury, which is proportional to the number of ice nuclei on leaf surfaces, is strongly determined by the particular bacterial strains that are present on a leaf surface. The INFs of strains were generally higher when they were grown on plants than when they were grown in culture. In addition, INFs in culture did not correlate closely with INFs on plants, suggesting that frost injury prediction should be based on INF measurements of cells grown on plants rather than in culture. The relative INFs of individual strains varied with plant host and environment. However, none of seven plant species tested optimized the INFs of all 15 strains. Similarly, incubation for 48 h at near 100% relative humidity with short photoperiods did not always decrease the INF when compared with a 72 h, 40% relative humidity, long-photoperiod incubation. Pathogenic strains on susceptible hosts were not associated with higher or lower INFs relative to their INFs on nonsusceptible plant species. The ice nucleation activity of individual bacterial strains on plants therefore appears to be controlled by complex and interacting factors such as strain genotype, environment, and host plant species.

O'Brien, R. Douglas; Lindow, Steven E.

1988-01-01

230

Fish communities and related environmental conditions of the lower Boise River, southwestern Idaho, 1974-2004  

USGS Publications Warehouse

Within the last century, the lower Boise River has been transformed from a meandering, braided, gravel-bed river that supported large runs of salmon to a channelized, regulated, urban river that provides flood control and irrigation water to more than 1,200 square miles of land. An understanding of the current status of the river's fish communities and related environmental conditions is important to support the ongoing management of the Boise River. Therefore, fish community data from the U.S. Geological Survey and the Idaho Department of Fish and Game collected since 1974 were analyzed to describe the status of fish communities in the lower Boise River. Each set of data was collected to address different study objectives, but is combined here to provide an overall distribution of fish in the lower Boise River over the last 30 years. Twenty-two species of fish in 7 families have been identified in the lower Boise River-3 salmonidae, trout and whitefish; 2 cottidae, sculpins; 3 catostomidae, suckers; 7 cyprinidae, minnows; 4 centrarchidae, sunfish; 2 ictaluridae, catfish; and 1 cobitidae, loach. Analysis of fish community data using an Index of Biotic Integrity (IBI) for Northwest rivers shows a decrease in the biotic integrity in a downstream direction, with the lowest IBI near the mouth of the Boise River. The number of tolerant and introduced fish were greater in the lower reaches of the river. Changes in land use, habitat, and water quality, as well as regulated streamflow have affected the lower Boise River fish community. IBI scores were negatively correlated with maximum instantaneous water temperature, specific conductance, and suspended sediment; as well as the basin land-use metrics, area of developed land, impervious surface area, and the number of major diversions upstream of a site. Fish communities in the upstream reaches were dominated by piscivorous fish, whereas the downstream reaches were dominated by tolerant, omnivorous fish. The percentage of sculpin in the river decreased in a downstream direction, and sculpin disappear completely at sites downstream of Glenwood Bridge. The sculpin population increased downstream of the Lander wastewater-treatment facility within the last decade, possibly as a result of improved wastewater treatment. The condition of the mountain whitefish (Prosopium williamsoni) throughout the lower Boise River was good and was similar both to the condition of mountain whitefish from least-disturbed rivers in southern Idaho and to the North American standard weight for mountain whitefish.

MacCoy, Dorene E.

2006-01-01

231

Feasibility of fiber Bragg grating and long-period fiber grating sensors under different environmental conditions.  

PubMed

This paper presents the feasibility of utilizing fiber Bragg grating (FBG) and long-period fiber grating (LPFG) sensors for nondestructive evaluation (NDE) of infrastructures using Portland cement concretes and asphalt mixtures for temperature, strain, and liquid-level monitoring. The use of hybrid FBG and LPFG sensors is aimed at utilizing the advantages of two kinds of fiber grating to implement NDE for monitoring strains or displacements, temperatures, and water-levels of infrastructures such as bridges, pavements, or reservoirs for under different environmental conditions. Temperature fluctuation and stability tests were examined using FBG and LPFG sensors bonded on the surface of asphalt and concrete specimens. Random walk coefficient (RWC) and bias stability (BS) were used for the first time to indicate the stability performance of fiber grating sensors. The random walk coefficients of temperature variations between FBG (or LPFG) sensor and a thermocouple were found in the range of -0.7499 °C/ [square root]h to -1.3548 °C/ [square root]h. In addition, the bias stability for temperature variations, during the fluctuation and stability tests with FBG (or LPFG) sensors were within the range of 0.01 °C/h with a 15-18 h time cluster to 0.09 °C/h with a 3-4 h time cluster. This shows that the performance of FBG or LPFG sensors is comparable with that of conventional high-resolution thermocouple sensors under rugged conditions. The strain measurement for infrastructure materials was conducted using a packaged FBG sensor bonded on the surface of an asphalt specimen under indirect tensile loading conditions. A finite element modeling (FEM) was applied to compare experimental results of indirect tensile FBG strain measurements. For a comparative analysis between experiment and simulation, the FEM numerical results agreed with those from FBG strain measurements. The results of the liquid-level sensing tests show the LPFG-based sensor could discriminate five stationary liquid-levels and exhibits at least 1,050-mm liquid-level measurement capacity. Thus, the hybrid FBG and LPFG sensors reported here could benefit the NDE development and applications for infrastructure health monitoring such as strain, temperature and liquid-level measurements. PMID:22163460

Wang, Jian-Neng; Tang, Jaw-Luen

2010-11-10

232

Feasibility of Fiber Bragg Grating and Long-Period Fiber Grating Sensors under Different Environmental Conditions  

PubMed Central

This paper presents the feasibility of utilizing fiber Bragg grating (FBG) and long-period fiber grating (LPFG) sensors for nondestructive evaluation (NDE) of infrastructures using Portland cement concretes and asphalt mixtures for temperature, strain, and liquid-level monitoring. The use of hybrid FBG and LPFG sensors is aimed at utilizing the advantages of two kinds of fiber grating to implement NDE for monitoring strains or displacements, temperatures, and water-levels of infrastructures such as bridges, pavements, or reservoirs for under different environmental conditions. Temperature fluctuation and stability tests were examined using FBG and LPFG sensors bonded on the surface of asphalt and concrete specimens. Random walk coefficient (RWC) and bias stability (BS) were used for the first time to indicate the stability performance of fiber grating sensors. The random walk coefficients of temperature variations between FBG (or LPFG) sensor and a thermocouple were found in the range of ?0.7499 °C/ h to ?1.3548 °C/ h. In addition, the bias stability for temperature variations, during the fluctuation and stability tests with FBG (or LPFG) sensors were within the range of 0.01 °C/h with a 15–18 h time cluster to 0.09 °C/h with a 3–4 h time cluster. This shows that the performance of FBG or LPFG sensors is comparable with that of conventional high-resolution thermocouple sensors under rugged conditions. The strain measurement for infrastructure materials was conducted using a packaged FBG sensor bonded on the surface of an asphalt specimen under indirect tensile loading conditions. A finite element modeling (FEM) was applied to compare experimental results of indirect tensile FBG strain measurements. For a comparative analysis between experiment and simulation, the FEM numerical results agreed with those from FBG strain measurements. The results of the liquid-level sensing tests show the LPFG-based sensor could discriminate five stationary liquid-levels and exhibits at least 1,050-mm liquid-level measurement capacity. Thus, the hybrid FBG and LPFG sensors reported here could benefit the NDE development and applications for infrastructure health monitoring such as strain, temperature and liquid-level measurements.

Wang, Jian-Neng; Tang, Jaw-Luen

2010-01-01

233

Modulation of nociceptive and acoustic startle responses to an unpredictable threat in men and women  

PubMed Central

The present study examined whether a moderately aversive abdominal threat would lead to greater enhancement in affect and pain-related defensive responding as indexed by the acoustic startle (ASR) and nociceptive flexion (NFR) reflex in women compared to men. We also predicted sex differences in threat-related autonomic arousal measured by skin conductance responses (SCR) to acoustic startle and noxious sural nerve stimulation. Unpredictable threat was manipulated by alternating 30 s safe (‘no abdominal stimulation will be given’) and threat (‘abdominal stimulation may occur at anytime’) periods. The experiment consisted of two blocks, each containing 4 safe and 4 threat periods in which the ASR or NFR was randomly probed 9-21 s following period onset. Unpredicatable abdominal threat potentiated both ASR and NFR responses compared to periods signaling safety. SCRs to acoustic startle probes and noxious sural nerve stimulation were also significantly elevated during the threat versus safe periods. No sex differences in ASR or startle-evoked SCRs emerged. However, nociceptive responding was moderated by sex; females showed significant increases in NFR magnitudes across both safe and threat periods compared to males. Females also showed greater threat potentiated SCRs to sural nerve stimulation than males. Our findings indicate that both affect and pain-related defense and arousal systems are strongly influenced by threat of an aversive, unpredictable event, a situation associated with anticipatory anxiety. Females compared to males, showed greater nociceptive responding and pain modulation when exposed to an unpredictable threatening context, whereas affect-driven ASR responses showed no such sex differentiation.

Hubbard, Catherine S.; Ornitz, Edward; Gaspar, John X.; Smith, Suzanne; Amin, Jennifer; Labus, Jennifer S.; Kilpatrick, Lisa A.; Rhudy, Jamie L.; Mayer, Emeran A.; Naliboff, Bruce D.

2011-01-01

234

Effect of Surface Finishing Materials on the Moisture Conditions in Concrete: Vapor and Water Permeability of Finishing Materials Under Changing Environmental Conditions  

Microsoft Academic Search

Permeability to vapor and water among other performances required for finishing materials is dealt with in this study. The relative moisture content of concrete coated\\/covered with a finishing material was experimentally investigated while changing the environmental conditions including temperature, relative humidity, and rainfall. An organic paint (water-based urethane), organic synthetic resin emulsion-type film coating (film coating E), and inorganic porcelain

Dong-Woo Ryu

235

Fragmentation and unpredictability of early-life experience in mental disorders.  

PubMed

Maternal sensory signals in early life play a crucial role in programming the structure and function of the developing brain, promoting vulnerability or resilience to emotional and cognitive disorders. In rodent models of early-life stress, fragmentation and unpredictability of maternally derived sensory signals provoke persistent cognitive and emotional dysfunction in offspring. Similar variability and inconsistency of maternal signals during both gestation and early postnatal human life may influence development of emotional and cognitive functions, including those that underlie later depression and anxiety. PMID:22885631

Baram, Tallie Z; Davis, Elysia P; Obenaus, Andre; Sandman, Curt A; Small, Steven L; Solodkin, Ana; Stern, Hal

2012-09-01

236

Experimental study of inequality and unpredictability in an artificial cultural market.  

PubMed

Hit songs, books, and movies are many times more successful than average, suggesting that "the best" alternatives are qualitatively different from "the rest"; yet experts routinely fail to predict which products will succeed. We investigated this paradox experimentally, by creating an artificial "music market" in which 14,341 participants downloaded previously unknown songs either with or without knowledge of previous participants' choices. Increasing the strength of social influence increased both inequality and unpredictability of success. Success was also only partly determined by quality: The best songs rarely did poorly, and the worst rarely did well, but any other result was possible. PMID:16469928

Salganik, Matthew J; Dodds, Peter Sheridan; Watts, Duncan J

2006-02-10

237

Chloroform in indoor swimming-pool air: monitoring and modeling coupled with the effects of environmental conditions and occupant activities.  

PubMed

Human exposure to chloroform in indoor swimming pools has been recognized as a potential health concern. Although environmental monitoring is a useful technique to investigate chloroform concentrations in indoor swimming-pool air, in practice, the interpretations of measured data would inevitably run into difficulties due to the complex interactions among the numerous variables, including environmental conditions and occupant activities. Considering of the relevant variables of environmental conditions and occupant activities, a mathematical model was first proposed to predict the chloroform concentration in indoor swimming-pool air. The developed model provides a straightforward, conceptually simple way to predict the indoor air chloroform concentration by calculating the mass flux, J, and the Péclet number, Pe, and by using a heuristic value of the indoor airflow recycle ratio, R. The good agreement between model simulation and measured data demonstrates the feasibility of using the presented model for indoor air quality management, operational guidelines and health-related risk assessment. PMID:19577784

Hsu, H T; Chen, M J; Lin, C H; Chou, W S; Chen, J H

2009-05-29

238

Effects of Individual Pre-Fledging Traits and Environmental Conditions on Return Patterns in Juvenile King Penguins  

Microsoft Academic Search

Despite the importance of early life stages in individuals' life history and population dynamics, very few studies have focused on the constraints to which these juvenile traits are subjected. Based on 10 years of automatic monitoring of over 2500 individuals, we present the first study on the effects of environmental conditions and individual pre-fledging traits on the post-fledging return of

Claire Saraux; Vincent A. Viblanc; Nicolas Hanuise; Yvon Le Maho; Céline Le Bohec

2011-01-01

239

Lubricity effect of carbon dioxide used as an environmentally friendly refrigerant in air-conditioning and refrigeration compressors  

Microsoft Academic Search

Environmental concerns have increased the interest in alternative natural refrigerants for air-conditioning and refrigeration compressors. Carbon dioxide (CO2) or R744 is an attractive candidate to replace harmful hydrofluorocarbon refrigerants, which will need to be replaced in the near future due to their high global warming potential. In this paper the tribological behavior of gray cast iron in the presence of

Emerson Escobar Nunez; Kyriaki Polychronopoulou; Andreas A. Polycarpou

2010-01-01

240

Life history interactions with environmental conditions in a host–parasite relationship and the parasite's mode of transmission  

Microsoft Academic Search

The microsporidian parasite Edhazardia aedis is capable of vertical or horizontal transmission among individuals of its host, the mosquito Aedes aegypti, and either mode of transmission may follow the other. We show that following the horizontal infection of host larvae, the parasite's subsequent mode of transmission largely depends on host life history traits and their responses to different environmental conditions.

Philip Agnew; Jacob C. Koella

1999-01-01

241

Effects of Environmental Conditions during Stream, Estuary, and Ocean Residency on Chinook Salmon Return Rates in the Skagit River, Washington  

Microsoft Academic Search

We predicted 22 years of return rates for wild Chinook salmon Oncorhynchus tshawytscha as a function of environmental conditions experienced during residency in freshwater, tidal delta, bay, and ocean habitats as well as as an indicator of density dependence (based on egg production) across life stages. The best predictors of return rate included the magnitude of floods experienced during incubation,

Correigh M. Greene; David W. Jensen; George R. Pess; E. Ashley Steel; Eric Beamer

2005-01-01

242

Evaluation of two-diode-model of a solar panel in a wide range of environmental conditions  

Microsoft Academic Search

In this article, a standard and comprehensive two-diode model of a solar cell is first fully described, and a solar panel model based on this model is developed. A measurement system is designed and implemented to evaluate the validity of the developed model. This measurement system is capable of extracting the electrical behaviour of solar panels in different environmental conditions.

Mohsen Taherbaneh; A. H. Rezaie; H. Ghafoorifard; K. Rahimi; M. B. Menhaj; J. M. Milimonfared

2011-01-01

243

Molecular evolution of the hyperthermophilic archaea of the Pyrococcus genus: analysis of adaptation to different environmental conditions  

Microsoft Academic Search

BACKGROUND: Prokaryotic microorganisms are able to survive and proliferate in severe environmental conditions. The increasing number of complete sequences of prokaryotic genomes has provided the basis for studying the molecular mechanisms of their adaptation at the genomic level. We apply here a computer-based approach to compare the genomes and proteomes from P. furiosus, P. horikoshii, and P. abyssi to identify

Konstantin V. Gunbin; Dmitry A. Afonnikov; Nikolay A. Kolchanov

2009-01-01

244

Potential energy savings and environmental impacts of energy efficiency standards for vapor compression central air conditioning units in China  

Microsoft Academic Search

Owing to the rapid development of economy and the stable improvement of people's living standard, central air conditioning units are broadly used in China. This not only consumes large energy, but also results in adverse energy-related environmental issues. Energy efficiency standards are accepted effective policy tools to reduce energy consumption and pollutant emissions. Recently, China issued two national energy efficiency

Wei Lu

2007-01-01

245

Assessing environmental conditions of the Río Champotón (México) using diverse indices and biomarkers in the fish Astyanax aeneus (Günther, 1860)  

Microsoft Academic Search

The upper reaches of the Río Champotón in southwestern Mexico are largely unknown to science. This river is sustaining anthropogenic and natural disturbances by deforestation, substitution of natural vegetation, and agricultural non-point source pollution. Furthermore, hurricanes provoke flooding of these areas, exposing the aquatic biota to pollutants. Several approaches were used to assess the effects of environmental conditions along the

Patricia Trujillo-Jiménez; J. Elías Sedeño-Díaz; J. A. Camargo; Eugenia López-López

2011-01-01

246

Essential Oil of Satureja montana, L. ssp. montana. Composition and Yields of Plants Grown Under Different Environmental Conditions  

Microsoft Academic Search

The yield and composition of essential oils of Satureja montana L. ssp. montana plants growing naturally in a calcareous, rocky and arid area were determined and compared with those that were transplanted and grown in environmental conditions different in altitude, light intensity and soil moisture.During the two years of experimentation the plants, which were found to be of the carvacrol

Anna Rita Bilia; Pierluigi Cioni; Ivano Morelli; Claudio Coppi; Angelo Lippi; Paolo E. Tomei

1992-01-01

247

Weeks Island brine diffuser site study: baseline conditions and environmental assessment technical report  

SciTech Connect

This technical report presents the results of a study conducted at two alternative brine diffuser sites (A and B) proposed for the Weeks Island salt dome, together with an analysis of the potential physical, chemical, and biological effects of brine disposal for this area of the Gulf of Mexico. Brine would result from either the leaching of salt domes to form or enlarge oil storage caverns, or the subsequent use of these caverns for crude oil storage in the Strategic Petroleum Reserve (SPR) program. Brine leached from the Weeks Island salt dome would be transported through a pipeline which would extend from the salt dome either 27 nautical miles (32 statute miles) for Site A, or 41 nautical miles (47 statute miles) for Site B, into Gulf waters. The brine would be discharged at these sites through an offshore diffuser at a sustained peak rate of 39 ft/sup 3//sec. The disposal of large quantities of brine in the Gulf could have a significant impact on the biology and water quality of the area. Physical and chemical measurements of the marine environment at Sites A and B were taken between September 1977 and July 1978 to correlate the existing environmental conditions with the estimated physical extent of tthe brine discharge as predicted by the MIT model (US Dept. of Commerce, 1977a). Measurements of wind, tide, waves, currents, and stratification (water column structure) were also obtained since the diffusion and dispersion of the brine plume are a function of the local circulation regime. These data were used to calculate both near- and far-field concentrations of brine, and may also be used in the design criteria for diffuser port configuration and verification of the plume model. Biological samples were taken to characterize the sites and to predict potential areas of impact with regard to the discharge. This sampling focused on benthic organisms and demersal fish. (DMC)

None

1980-12-12

248

Ultrastructure of potato tubers formed in microgravity under controlled environmental conditions.  

PubMed

Previous spaceflight reports attribute changes in plant ultrastructure to microgravity, but it was thought that the changes might result from growth in uncontrolled environments during spaceflight. To test this possibility, potato explants were examined (a leaf, axillary bud, and small stem segment) grown in the ASTROCULTURETM plant growth unit, which provided a controlled environment. During the 16 d flight of space shuttle Columbia (STS-73), the axillary bud of each explant developed into a mature tuber. Upon return to Earth, tuber slices were examined by transmission electron microscopy. Results showed that the cell ultrastructure of flight-grown tubers could not be distinguished from that of tuber cells grown in the same growth unit on the ground. No differences were observed in cellular features such as protein crystals, plastids with starch grains, mitochondria, rough ER, or plasmodesmata. Cell wall structure, including underlying microtubules, was typical of ground-grown plants. Because cell walls of tubers formed in space were not required to provide support against the force due to gravity, it was hypothesized that these walls might exhibit differences in wall components as compared with walls formed in Earth-grown tubers. Wall components were immunolocalized at the TEM level using monoclonal antibodies JIM 5 and JIM 7, which recognize epitopes of pectins, molecules thought to contribute to wall rigidity and cell adhesion. No difference in presence, abundance or distribution of these pectin epitopes was seen between space- and Earth-grown tubers. This evidence indicates that for the parameters studied, microgravity does not affect the cellular structure of plants grown under controlled environmental conditions. PMID:12867548

Cook, Martha E; Croxdale, Judith G

2003-07-16

249

Relations between introduced fish and environmental conditions at large geographic scales  

USGS Publications Warehouse

Data collected from 20 major river basins between 1993 and 1995 as part of the US Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) Program were analyzed to assess patterns in introduced and native fish species richness and abundance relative to watershed characteristics and stream physicochemistry. Sites (N = 157) were divided into three regions-northeast, southeast, and west- to account for major longitudinal differences in precipitation/runoff and latitudinal limits of glaciation that affect zoogeographic patterns in fish communities. Common carp (Cyprinus carpio) and largemouth bass (Micropterus salmoides) were the most frequently collected introduced fish species across all river basins combined. Based on the percentage of introduced fish species, the fish communities most altered by the presence of introduced fish occurred in the western and northeastern parts of the US. Native fish species richness was not an indicator of introduced fish species richness for any of the three regions. However, in the west, introduced fish species richness was an indicator of total fish species richness and the abundance of introduced fish was negatively related to native fish species richness. Some relations between introduced fish species and environmental conditions were common between regions. Increased introduced fish species richness was related to increased population density in the northeast and southeast; increased total nitrogen in the northeast and west; and increased total phosphorous and water temperature in the southeast and west. These results suggest that introduced fish species tend to be associated with disturbance at large geographic scales, though specific relations may vary regionally. ?? 2003 Elsevier Science Ltd. All rights reserved.

Meador, M. R.; Brown, L. R.; Short, T.

2003-01-01

250

Conditional switching: a new variety of regression with many potential environmental applications.  

PubMed Central

We introduce a new form of regression that has many applications to environmental studies. For a sequence composed of key variates with prototypic value chi, this form differs from the estimation of a location parameter-based curve, mu(chi), a scale parameter-based curve, sigma(chi), or other currently used types of regression. Instead of estimating a curve location, scale, or alpha-quantile parameter, it assumes that there are two or more population subgroups; for example, consisting of unsensitized and sensitized individuals, respectively. Although within each subgroup the relationships mu(chi) or sigma(chi) may or may not be horizontal, these relationships are not deemed to be of primary importance. Instead, the mixing parameter P that indexes the proportions of the two subgroups is treated as being related to the key variate value chi. In the sense that its goal is the estimation of a proportion, the new procedure resembles logit regression. But, in terms of the continuous spectrum of values attained by the response variate, the means used to attain its goal are dissimilar from those of logit regression. Specifically, group membership is not known directly but is determined from a proxy continuous variate whose values overlap between groups. Examples are given with simulated and natural data where this new form of regression is applied. We believe that conditional switching regression is a particularly valuable research tool when chemical level chi of an induced asthma attack or birthweight chi measured in a study of the biomarker cotinine's effect on pregnancy outcomes determines whether an attack or a negative outcome occurs.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure C-1. Figure C-1. Figure C-1. Figure C-1. Figure C-1. Figure C-1. Figure D-1. Figure D-2.

Tarter, M E; Lock, M D; Ray, R M

1995-01-01

251

Amoxicillin-degradation products formed under controlled environmental conditions: identification and determination in the aquatic environment.  

PubMed

Amoxicillin (AMX) is a widely used penicillin-type antibiotic whose presence in the environment has been widely investigated, despite its rapid hydrolysis to various degradation products (DPs). In this work, the formation of AMX DPs was studied in various aqueous solutions containing 100?gmL(-1) AMX. Three phosphate buffer solutions, at pH 5, pH 7 and pH 8, and a fourth buffer solution at pH 7 with the addition of the bivalent ions Mg(2+)and Ca(2) as chelating agents, were examined under controlled environmental conditions. In addition, two solutions from natural sources were examined secondary effluents and tap water. The obtained DPs were identified by their MS/MS, UV and NMR spectra (obtained from pure compounds isolated by preparative HPLC) as: AMX penicilloic acid (ADP1/2), AMX penilloic acid (ADP4/5) and phenol hydroxypyrazine (ADP6). Two additional detected DPs AMX 2',5'-diketopiperazine (ADP8/9), and AMX-S-oxide (ADP3) were reported and discussed in our previous publications. These DPs were then detected in secondary effluent and groundwater from a well located beneath agricultural fields continuously irrigated with secondary effluent. Concentrations in the secondary effluent were: ADP1/2, several micrograms per liter; ADP4/5, 0.15?gL(-1), and ADP8/9, 0.5?gL(-1). ADP6 were detected but not quantified. In the groundwater, only ADP8/9 was detected, at a concentration of 0.03?gL(-1). The detection and quantification of DPs of other investigated drugs is recommended as an integral part of any study, method or technique dealing with pharmaceutical residues in aquatic environments. PMID:23466086

Gozlan, Igal; Rotstein, Adi; Avisar, Dror

2013-03-07

252

Growth conditions and environmental factors impact aerosolization but not virulence of Francisella tularensis infection in mice  

PubMed Central

In refining methodology to develop a mouse model for inhalation of Francisella tularensis, it was noted that both relative humidity and growth media impacted the aerosol concentration of the live vaccine strain (LVS) of F. tularensis. A relative humidity of less than 55% had a negative impact on the spray factor, the ratio between the concentration of LVS in the aerosol and the nebulizer. The spray factor was significantly higher for LVS grown in brain heart infusion (BHI) broth than LVS grown in Mueller–Hinton broth (MHb) or Chamberlain's chemically defined medium (CCDM). The variability between aerosol exposures was also considerably less with BHI. LVS grown in BHI survived desiccation far longer than MHb-grown or CCDM-grown LVS (~70% at 20 min for BHI compared to <50% for MHb and CCDM). Removal of the capsule by hypertonic treatment impacted the spray factor for CCDM-grown LVS or MHb-grown LVS but not BHI-grown LVS, suggesting the choice of culture media altered the adherence of the capsule to the cell membrane. The choice of growth media did not impact the LD50 of LVS but the LD99 of BHI-grown LVS was 1 log lower than that for MHb-grown LVS or CCDM-grown LVS. Splenomegaly was prominent in mice that succumbed to MHb- and BHI-grown LVS but not CCDM-grown LVS. Environmental factors and growth conditions should be evaluated when developing new animal models for aerosol infection, particularly for vegetative bacterial pathogens.

Faith, Seth A.; Smith, Le'Kneitah P.; Swatland, Angela S.; Reed, Douglas S.

2012-01-01

253

Quantification of vapor intrusion pathways into a slab-on-ground building under varying environmental conditions.  

PubMed

Potential hydrocarbon-vapor intrusion pathways into a building through a concrete slab-on-ground were investigated and quantified under a variety of environmental conditions to elucidate the potential mechanisms for indoor air contamination. Vapor discharge from the uncovered open ground soil adjacent to the building and subsequent advection into the building was unlikely due to the low soil-gas concentrations at the edge of the building as a result of aerobic biodegradation of hydrocarbon vapors. When the building's interior was under ambient pressure, a flux of vapors into the building due to molecular diffusion of vapors through the building's concrete slab (cyclohexane 11 and methylcyclohexane 31 mg m(-2) concrete slab day(-1)) and short-term (up to 8 h) cyclical pressure-driven advection of vapors through an artificial crack (cyclohexane 4.2 x 10(3) and methylcyclohexane 1.2 x 10(4) mg m(-2) cracks day(-1)) was observed. The average subslab vapor concentration under the center of the building was 25,000 microg L(-1). Based on the measured building's interiorvapor concentrations and the building's air exchange rate of 0.66 h(-1), diffusion of vapors through the concrete slab was the dominantvapor intrusion pathway and cyclical pressure exchanges resulted in a near zero advective flux. When the building's interior was under a reduced pressure (-12 Pa), advective transport through cracks or gaps in the concrete slab (cyclohexane 340 and methylcyclohexane 1100 mg m(-2) cracks day(-1)) was the dominant vapor intrusion pathway. PMID:19244997

Patterson, Bradley M; Davis, Greg B

2009-02-01

254

Safety conditioning technology for mining region's environmental system based on Catastrophe Theory  

Microsoft Academic Search

The safety of mining region's environmental system is a basic prerequisite of the sustainable development of mining region's economy and society. The maintenance of mining region's environmental system safety by taking effective measures has great significance for mining regions in China function as residential community. One of the major problems facing mining region's sustainable development is how to keep the

Dachao Zhang

2011-01-01

255

Long-term human response to uncertain environmental conditions in the Andes  

Microsoft Academic Search

Human interaction with the physical environment has increasingly transformed Earth-system processes. Reciprocally, climate anomalies and other processes of environmental change of natural and anthropogenic origin have been affecting, and often disrupting, societies throughout history. Transient impact events, despite their brevity, can have significant long-term impact on society, particularly if they occur in the context of ongoing, protracted environmental change. Major

Tom D. Dillehay; Alan L. Kolata

2004-01-01

256

Inheritable Effect of Unpredictable Maternal Separation on Behavioral Responses in Mice  

PubMed Central

The long-term impact of early stress on behavior and emotions is well documented in humans, and can be modeled in experimental animals. In mice, maternal separation during early postnatal development induces poor and disorganized maternal care, and results in behavioral deficits that persist through adulthood. Here, we examined the long-term effect of unpredictable maternal separation combined with maternal stress on behavior and its transmissibility. We report that unpredictable maternal separation from birth to postnatal day 14 in C57Bl/6J mice has mild behavioral effects in the animals when adult, but that its combination with maternal stress exacerbates this effect. Further, the behavioral deficits are transmitted to the following generation through females, an effect that is independent of maternal care and is not affected by cross-fostering. The combined manipulation does not alter basic components of the hypothalamic–pituitary–adrenal axis but decreases the expression of the corticotropin releasing factor receptor 2 (CRFR2) in several nuclei of the amygdala and the hypothalamus in the brain of maternal-separated females. These results suggest a non-genomic mode of transmission of the impact of early stress in mice.

Weiss, Isabelle C.; Franklin, Tamara B.; Vizi, Sandor; Mansuy, Isabelle M.

2011-01-01

257

Achieving compliance with environmental health-related land use planning conditions in Hong Kong: perspectives from traditional motivation theories.  

PubMed

Environmental health-related land use planning conditions can enhance the environment in Hong Kong. Previous research by others has shown, however, that a lack of compliance with planning conditions often occurs. And as no direct enforcement of planning conditions exists in Hong Kong, it is of interest to understand possible ways in which to increase the motivation of land developers and property owners to comply with planning conditions. The author looked at motivation from the perspective of three traditional motivation theories: Theory X, Theory Y, and incentive theory. While the majority of this article focuses on the enforcement and the legal tests in land use planning conditions, it also presents the results of the first study of the motivations behind Hong Kong land developers to comply with land use planning conditions. PMID:19908435

Man, Rita Li Yi

2009-11-01

258

Short-term synaptic plasticity in the deterministic Tsodyks-Markram model leads to unpredictable network dynamics  

PubMed Central

Short-term synaptic plasticity strongly affects the neural dynamics of cortical networks. The Tsodyks and Markram (TM) model for short-term synaptic plasticity accurately accounts for a wide range of physiological responses at different types of cortical synapses. Here, we report a route to chaotic behavior via a Shilnikov homoclinic bifurcation that dynamically organizes some of the responses in the TM model. In particular, the presence of such a homoclinic bifurcation strongly affects the shape of the trajectories in the phase space and induces highly irregular transient dynamics; indeed, in the vicinity of the Shilnikov homoclinic bifurcation, the number of population spikes and their precise timing are unpredictable and highly sensitive to the initial conditions. Such an irregular deterministic dynamics has its counterpart in stochastic/network versions of the TM model: The existence of the Shilnikov homoclinic bifurcation generates complex and irregular spiking patterns and—acting as a sort of springboard—facilitates transitions between the down-state and unstable periodic orbits. The interplay between the (deterministic) homoclinic bifurcation and stochastic effects may give rise to some of the complex dynamics observed in neural systems.

Cortes, Jesus M.; Desroches, Mathieu; Rodrigues, Serafim; Veltz, Romain; Munoz, Miguel A.; Sejnowski, Terrence J.

2013-01-01

259

Effects of Environmental Conditions on Activity, Feeding, and Body Weight in Male and Female Adolescent Rats.  

National Technical Information Service (NTIS)

Excessive body weight, particularly in children, is a growing concern in the United States and around the world. Body weight is affected by feeding behavior and physical activity. Environmental factors affect feeding behaviors and physical activity; there...

J. L. Tomchesson

2006-01-01

260

40 CFR 86.1312-2007 - Filter stabilization and microbalance workstation environmental conditions, microbalance...  

Code of Federal Regulations, 2013 CFR

40 Protection of Environment 20 2013-07-01 2013-07-01...86.1312-2007 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... (i) The filter stabilization environment shall be maintained at 22 °C...

2013-07-01

261

The effects of stimulus preexposure on taste-mediated environmental conditioning: Potentiation and overshadowing  

Microsoft Academic Search

On four occasions, Holtzman rats drank saccharin in a distinctive environment prior to lithium-induced toxicosis. Preconditioning\\u000a exposure to saccharin either in the home cage or in the distinctive environment interfered significantly with the establishment\\u000a of an environmental aversion. Animals preexposed to the experimental environment, however, showed environmental aversions\\u000a substantially stronger than those in animals preexposed to saccharin and only slightly

Michael R. Best; Cynthia L. Meachum

1986-01-01

262

Impact of nitrogen and environmental conditions on corn as detected by hyperspectral reflectance  

Microsoft Academic Search

Indices derived from hyperspectral reflectance spectra have the potential to be used as indicators of environmental stress in crops. This study uses canopy-scale, ground-based measurements of hyperspectral reflectance to demonstrate the temporal patterns in corn development under imposed fertility (N rate) and environmental (water availability) stresses. In 1998, two large areas in a 30-ha corn (Zea mays, L.) field near

Ian B. Strachan; Elizabeth Pattey; Johanne B. Boisvert

2002-01-01

263

Household Environmental Conditions Are Associated with Enteropathy and Impaired Growth in Rural Bangladesh  

PubMed Central

We assessed the relationship of fecal environmental contamination and environmental enteropathy. We compared markers of environmental enteropathy, parasite burden, and growth in 119 Bangladeshi children (? 48 months of age) across rural Bangladesh living in different levels of household environmental cleanliness defined by objective indicators of water quality and sanitary and hand-washing infrastructure. Adjusted for potential confounding characteristics, children from clean households had 0.54 SDs (95% confidence interval [CI] = 0.06, 1.01) higher height-for-age z scores (HAZs), 0.32 SDs (95% CI = ?0.72, 0.08) lower lactulose:mannitol (L:M) ratios in urine, and 0.24 SDs (95% CI = ?0.63, 0.16) lower immunoglobulin G endotoxin core antibody (IgG EndoCAb) titers than children from contaminated households. After adjusting for age and sex, a 1-unit increase in the ln L:M was associated with a 0.33 SDs decrease in HAZ (95% CI = ?0.62, ?0.05). These results are consistent with the hypothesis that environmental contamination causes growth faltering mediated through environmental enteropathy.

Lin, Audrie; Arnold, Benjamin F.; Afreen, Sadia; Goto, Rie; Huda, Tarique Mohammad Nurul; Haque, Rashidul; Raqib, Rubhana; Unicomb, Leanne; Ahmed, Tahmeed; Colford, John M.; Luby, Stephen P.

2013-01-01

264

Sensitivity of modelled channel network formation to environmental conditions and initial bathymetry  

NASA Astrophysics Data System (ADS)

Estuaries show a variety of distinctive geomorphic features that reflect differences in environmental conditions, such as geological constraints, hydrodynamic forcing (e.g. tidal range, wave climate), sediment loads from the catchment, and the presence and types of both vegetation and benthic organisms. These differences yield varying patterns of sediment erosion/deposition and consequently determine the current shape of the estuary and its future evolution. Understanding how estuarine systems evolve as a function of both natural and anthropogenic drivers is still a main research topic in coastal science. Both the short- and long-term evolution of estuaries are affected by the dynamics related to tidal channel networks. Channel networks often exhibit complex morphological patterns and their initial formation is not entirely understood. Also, the subsequent evolution of channel networks can be accompanied by the development of tidal flats which provide ecologically important habitats. Despite their importance, observations of channel network formation involve large spatial and temporal scales so that detailed studies have rarely been reported. Recently, modelling approaches have been developed to study the long-term evolution of tidal basins and the associated formation of channel patterns. A model has been developed to simulate the formation of channel networks and tidal flats as a result of the interactions between hydrodynamics, sediment transport, and bed elevation change. Simulations were undertaken using idealised initial bathymetries. Flow velocities are computed using an open source numerical model (ELCOM; Estuary and Lake Computer Model) that solves the unsteady Reynolds-averaged Navier-Stokes equations for incompressible flow using the hydrostatic assumption. The computed flow velocities drive sediment transport, which is calculated using formulas widely adopted in sediment transport studies. Gradients in sediment transport rate yield morphological change which feed back into the hydrodynamic part of the model, thus coupling the different subsystems of the morphodynamic feedback loop. Hydrodynamic conditions are assumed to remain constant unless significant changes in the morphology have occurred. This allows us to reduce numerical effort and facilitates the execution of long-term simulations. Modelling results indicate that the morphodynamic interactions can cause channel initiation and potentially give rise to channel pattern development. A sensitivity analysis is performed to show that the sediment grain size and tidal range mainly affect the timescale over which channel initiation occurs. We also varied the initial depth of the basin to assess the influence of initial bathymetry on morphological change. Channels start to form rapidly in the case of a shallow basin. When the basin is deeper, the bathymetry evolves differently in a remarkable way. While channels develop in the upper part of the basin, a flood-tidal delta forms simultaneously just landward of the inlet. Eventually, this flood delta channelizes and a complete tidal channel network develops. Additional simulations also indicate that effects related to climate change (i.e. sea level rise) highly affect the overall morphological evolution of tidal environments.

van Maanen, Barend; Coco, Giovanni; Bryan, Karin

2010-05-01

265

Thermo-mechanical response of poly(methyl methacrylate) (PMMA) large volumes exposed to time-dependent environmental conditions  

NASA Astrophysics Data System (ADS)

Low thermal conductivity and elevated absorbance of large bulky volumes of poly(methyl methacrylate) (PMMA) exposed to moderately aggressive environmental conditions may cooperate to determine critical mechanical conditions, kindling unexpected high thermal stresses values which lead the material to failure. From the engineering point of view, this can be explained as the result of two concomitant phenomena which activate a cascade of events: very sharp thermal gradients engendered by transient thermal processes induced by cyclic environmental conditions, combined with significant bulk heat generation due to the high thermal inertia of massive PMMA volumes, in turn aggravating the steepness of the thermal gradients, may in fact ingenerate severe stress regimes, potentially undermining the structural stability of the material. Moving from these considerations, the present study is aimed to investigate possible rupture of PMMA blocks experiencing heating processes as a consequence of their exposure to outdoor cyclic environmental conditions. The problem is approached by means of both rigorous analytical arguments and the Finite Element based numerical methods, finally exploiting the theoretical outcomes to formulate a hypothesis which might explain the still unclear phenomenon of the sudden breaking of the PMMA structure, named Huge Wine Glass and designed by the world famous Japanese architect Toyo Ito, which occurred in Pescara (Italy) in 2009.

Fraldi, M.; Esposito, L.; Perrella, G.; Cutolo, A.

2013-09-01

266

conditions  

Microsoft Academic Search

Real-time scheduling is both based on a broad theoretical background and available through a multitude of tools and infrastructures. The central input parameters to this discipline are the demand for execution time and the real- time conditions given as deadlines or periods. The former has attracted a lot of research efforts, mainly in the scope of worst case execution time

Dieter Z

267

Versatility of soil column experiments to study biodegradation of halogenated compounds under environmental conditions  

Microsoft Academic Search

Soil column experiments were performed to obtain insight in the different biological and physico-chemical processes affecting biodegradation of halogenated compounds under natural conditions in a water infiltration site. Lower chlorinated aromatic compounds could be degraded under aerobic conditions, whereas highly chlorinated compounds and chlorinated aliphatic compounds were mainly transformed under anaerobic conditions. Microorganisms which derive energy from reductive dechlorination were

Jan Roelof van der Meer; Tom N. P. Bosma; Wil P. Bruin; Hauke Harms; Christof Holliger; Huub H. M. Rijnaarts; Marijke E. Tros; Gosse Schraa; Alexander J. B. Zehnder

1992-01-01

268

Chasin' choppers: using unpredictable trajectories to test theories of object interception.  

PubMed

Three theories of the informational basis for object interception strategies were tested in an experiment where participants pursued toy helicopters. Helicopters were used as targets because their unpredictable trajectories have different effects on the optical variables that have been proposed as the basis of object interception, providing a basis for determining the variables that best explain this behavior. Participants pursued helicopters while the positions of both pursuer and helicopter were continuously monitored. Using models to predict the observed optical trajectories of the helicopter and ground positions of the pursuer, optical acceleration was eliminated as a basis of object interception. A model based on control of optical velocity (COV) provided the best match to pursuer ground movements, while one based on segments of linear optical trajectories (SLOT) provided the best match to the observed optical trajectories. We describe suggestions for further research to distinguish the COV and SLOT models. PMID:23864264

Shaffer, Dennis M; Marken, Richard S; Dolgov, Igor; Maynor, Andrew B

2013-10-01

269

Unpredictable endocrinology of the menopause transition: clinical, diagnostic and management implications.  

PubMed

The approach to menopause can be divided into the early (E) and late (L) menopausal transitions (MT) on the basis of menstrual irregularity (EMT) and subsequent observation of at least one episode of 60 or more days amenorrhoea (LMT). In total, 40-60% of cycles in the LMT are anovulatory, often with low oestradiol (E2) and high follicle-stimulating hormone concentrations. The ovulatory cycles have variable endocrine characteristics, none of which is specific to EMT or LMT. Hormonal measurements of FSH and E2 are thus of little diagnostic value because of their unpredictable variability. Symptoms during the transitions may result from high or low E2 and can often be satisfactorily managed with low-dose oral contraceptives, which suppress pituitary-ovarian function. PMID:22120939

Burger, Henry G

2011-11-25

270

[Comment on Earthquake precursors: Banished forever?] Comment: Unpredictability of earthquakes-Truth or fiction?  

NASA Astrophysics Data System (ADS)

I was delighted to read Alexander Gusev's opinions on what he calls the “unpredictability paradigm” of earthquakes (Eos, February 10, 1998, p. 71). I always enjoy hearing from a good friend in the pages of Eos. I immediately looked up “paradigm” in my Oxford Dictionary and found this: paradigm n 1) set of all the different forms of a word: verb paradigms. 2) Type of something; pattern; model: a paradigm for others to copy.I wonder whether Sasha Gusev actually believes that branding earthquake prediction a “proven nonscience” [Geller, 1997] is a paradigm for others to copy. As for me, I choose to refrain from climbing on board this particular bandwagon for the following reasons.

Lomnitz, Cinna

271

Primary Mesenteric Smooth Muscle Tumor: An Entity with Unpredictable Biologic Behavior  

PubMed Central

Smooth muscle tumors of the mesentery are rare lesions with unpredictable, usually malignant, biologic behavior irrespective of their histologic appearance. Such case is presented here. We present a case of a large smooth muscle tumor located in the mesentery of a 48 years old patient. The histopathologic features of the surgically excised tumor were that of a benign-appearing smooth muscle tumor, either a primary mesenteric smooth muscle tumor of unknown biologic behavior or a parasitic leiomyoma. The patient was discharged 4 days after from the hospital without any early postoperative complication. Close followup was further decided. Nine months after her primary therapy, our patient is alive and with no evidence of recurrent disease. Increased awareness must be considered for large mesenteric smooth muscle tumors, because even when they present indolent histologic features, they usually behave aggressively.

Kalogiannidis, Ioannis; Stavrakis, Thomas; Amplianitis, Ioannis; Grammenou, Sophia; Mavromatidis, Georgios; Rousso, David

2013-01-01

272

Conditions  

Microsoft Academic Search

A shallow, RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine)- contaminated aquifer at Naval Submarine Base Bangor has been characterized as predominantly manganese-reducing, anoxic with local pockets of oxic conditions. The potential contribution of microbial RDX degradation to localized decreases observed in aquifer RDX concentrations was assessed in sediment microcosms amended with (U- 14 C) RDX. Greater than 85% mineralization of 14 C-RDX to 14 CO2

Paul M. Bradley; Richard S. Dinicola

273

Environmental and Resource Costs Under Water Scarcity Conditions: An Estimation in the Context of the European Water Framework Directive  

Microsoft Academic Search

The European Water Framework Directive (WFD) requires the good ecological status of surface water bodies, which implies the\\u000a improvement of both their physicochemical condition, as well as their flow and continuity. The WFD prescribes the assessment\\u000a of environmental and resource costs and benefits associated with implementing these improvements. The recent literature focuses\\u000a almost exclusively on the assessment of the economic

Julia Martin-Ortega; Giacomo Giannoccaro; Julio Berbel

2011-01-01

274

Comparison between algae-based and duckweed-based wastewater treatment: differences in environmental conditions and nitrogen transformations  

Microsoft Academic Search

In laboratory-scale batch experiments, duckweed (Limna gibba)-based and algae-based wastewater containers have been monitored over 15 days in two experiments with different initial total nitrogen concentrations of 50 (experiment 1) and 100 mg-N\\/L (experiment 2). Clear differences in environmental conditions were observed. High dissolved oxygen (DO) concentrations were observed in the algae-based ,compared to duckweed-based, containers. In the algae-based containers

O. R. Zimmo; R. Al; Sa' ed; H. Gijzen

275

The influence of environmental conditions on the seasonal variation of Microcystis cell density and microcystins concentration in San Francisco Estuary  

Microsoft Academic Search

A bloom of the cyanobacteria Microcystis\\u000a aeruginosa was sampled over the summer and fall in order to determine if the spatial and temporal patterns in cell density, chlorophyll\\u000a a (chl a) concentration, total microcystins concentration, and percent microcystins composition varied with environmental conditions\\u000a in San Francisco Estuary. It was hypothesized that the seasonal variation in Microcystis cell density and microcystin

P. W. Lehman; G. Boyer; M. Satchwell; S. Waller

2008-01-01

276

The Peroxisomal Ascorbate–Glutathione Pathway: Molecular Identification and Insights into Its Essential Role Under Environmental Stress Conditions  

Microsoft Academic Search

\\u000a Peroxisomes are unique organelles with intricate biochemical machinery­ involved in oxidative stress management and signaling.\\u000a Peroxisomal metabolism is characterized by its plasticity because the organelle’s enzyme composition varies depending on the\\u000a cell type, stage of development, and environmental conditions. The present chapter reviews recent progress in understanding\\u000a the metabolism of reactive oxygen species (ROS) in plant peroxisomes. The ascorbate–glutathione (AsA–GSH)

Sigrun Reumann; Francisco J. Corpas

277

Method and system for calculating the spatial-temporal effects of climate and other environmental conditions on animals  

US Patent & Trademark Office Database

The present invention is a system and method for accurately calculating the spatial-temporal effects of a variety of environmental conditions on animal individual, population and community dynamics, given the animal's temperature-dependent behaviors, morphology and physiology, by running integrated microclimate and animal models to calculate the discretionary energy and water available to the animal and its activity time. The methodology requires relatively few, easily measured data to perform the calculations. The microclimate model translates a set of climate and other environmental conditions into a set of microclimate conditions experienced by an animal, given a set of the animal's characteristics. The animal model uses the microclimate conditions data and the set of animal characteristics data to solve for several animal conditions. Further calculations and several display options are available to a user, including spatial-temporal analyses. The method is implemented by use of a client-server system employing a graphical user interface, and a programming structure that allows for use of the methodology with personal computers, despite the large sizes of the databases that must be accessed. The method may also be implemented on individual computers.

2006-12-26

278

Distribution, abundance, and diversity of stream fishes under variable environmental conditions  

Microsoft Academic Search

The effects of stream size and flow regime on spatial and temporal variability of stream fish distribution, abundance, and diversity patterns were investigated. Assemblage variability and species richness were each significantly associated with a complex environmental gradient contrasting smaller, hydrologically variable stream localities with larger localities characterized by more stable flow regimes. Assemblages showing the least variability were the most

Christopher M. Taylor; Thomas L. Holder; Riccardo A. Fiorillo; Lance R. Williams; R. Brent Thomas

2006-01-01

279

Strong clustering of underdense regions and the environmental dependence of clustering from Gaussian initial conditions  

Microsoft Academic Search

We discuss two slightly counterintuitive findings about the environmental dependence of clustering in the Sloan Digital Sky Survey. First, we find that the relation between clustering strength and density is not monotonic: galaxies in the densest regions are more strongly clustered than are galaxies in regions of moderate overdensity; galaxies in moderate overdensities are more strongly clustered than are those

Ummi Abbas; Ravi K. Sheth

2007-01-01

280

Environmental Supports to Improve Outcomes in Schizophrenia and other Conditions with Cognitive Impairment  

Microsoft Academic Search

The reliability and cross-cultural validity of the Allen Cognitive Levels assessment will be discussed. We will describe the work of Claudia Allen as it applies to the development of Cognitive Adaptation Training (CAT) a psychosocial treatment that uses environmental supports to cue and sequence adaptive behavior in the home environment and improve functional outcomes in patients with schizophrenia. CAT interventions

Dawn I. Velligan

281

Cultural and environmental factors governing tomato production: Local food production under elevated temperature conditions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Long-term fresh tomato (Solanum lycopersicum L.) production data was used to estimate cultural and environmental impacts on marketable tomato yields in eastern Oklahoma. Quantifying the interactive effects of planting date and growing season duration and the effects of cumulative heat units and heat...

282

Climate Change in China from 1880 to 1998 and its Impact on the Environmental Condition  

Microsoft Academic Search

The global mean surface air temperature (SAT) or the Northern Hemisphere mean SAT has increased since the late nineteenth century, but the mean precipitation around the world has not formed a definite tendency to increase. A lot of studies showed that different climate and environmental changes during the past 100 years over various regions in the world were experienced. The

Weihong Qian; Yafen Zhu

2001-01-01

283

Summary Report on Environmental Conditions at 13 European Man Made Mineral Fibre Plants.  

National Technical Information Service (NTIS)

A series of environmental surveys was carried out at 13 European Man Made Mineral Fibre Production Plants on behalf of the Joint European Medical Research Board. The principle aim of these surveys was to determine the airborne fibre concentrations and fib...

J. Ottery J. Cherrie J. Dodgson G. Harrison

1982-01-01

284

EFFECTS OF COAL MINING TO THE ENVIRONMENTAL CONDITIONS OF THE EAST BORSOD BASIN  

Microsoft Academic Search

To the NE of Miskolc city in the hilly foreground (East-Borsod coal basin) of the Bükk Mountains made up mainly of Miocene molasse sediments, Ottnangian-Karpathian brown coal deposits have been under exploitation for almost 200 years (Fig. 1). Therefore we tried to estimate the spatial extent of surface subsidence induced by headings and to measure environmental effects of the waste

L. SÜT?; M. KOZÁK; Z. PÜSPÖKI

285

The Normandy field study on juvenile osteochondral conditions: conclusions regarding the influence of genetics, environmental conditions and management, and the effect on performance.  

PubMed

Juvenile osteochondral conditions (JOCC) have a major impact on the equine industry and include many musculoskeletal disorders of the young horse, of which osteochondrosis (OC) is the most prominent. The Breeding, Osteochondral Status and Athletic Career (BOSAC) project is the first large, comprehensive, longitudinal field study on the subject conducted in three breeds of performance horses (Thoroughbreds, Standardbred Trotters and Warmbloods) that were monitored in their natural environment where they were reared under common field conditions. The BOSAC study used a radiographic protocol designed for field use coupled to an internally validated severity scoring system, providing weighted radiographic findings as the primary outcome measure. The natural courses of various JOCC appear to differ, according to the joint and condition involved. Genetically, there were also large differences with moderate heritabilities in the tarsocrural and metacarpophalangeal/metatarsophalangeal joints and virtually no heritability for femoropatellar OC. There was a strong influence of exercise history (as an environmental condition) on the manifestation and natural course of JOCC. In the younger age class (<6months) lack of exercise or irregular exercise had a negative effect, as had exposure to excessive exercise. In the yearling category, (exercise-associated) intrinsic trauma seemed to be the most important negative factor. In terms of later function, the association of a poor radiographic score with poorer performance in racing Trotters could be demonstrated. PMID:23639367

van Weeren, P René; Denoix, Jean-Marie

2013-04-29

286

How strategic dynamics complicate the framing of alternatives in strategic environmental assessment: the case of the Danish natural gas planning  

Microsoft Academic Search

Unpredictable and complex developments challenge the application of strategic environmental assessment (SEA), for example, in terms of timing, prediction and relevance of assessments. In particular, multi-actor and unstructured strategic-level decision-making processes often seem to be characterised by unpredictable and complex changes. Despite the apparent implications, explorative investigations about how unpredictability influences SEA application in practice are rare. This article aims

Ivar Lyhne

2012-01-01

287

Pyrite Flotation With Xanthate Under Alkaline Conditions — Application to Environmental Desulfurisation  

Microsoft Academic Search

The extensive literature on sulfide flotation indicates that pyrite poorly floats under alkaline condition. Xanthate concentration has a positive effect on pyrite flotation, but above a pH of 11, pyrite seems to be strongly depressed, independently of the concentration in xanthate. In this investigation, aeration and xanthate concentration effects were studied for pyrite flotation conditioned at pH 11 with lime.

R Mermillod-Blondin; M Kongolo; P de Donato; M Benzaazoua; O Barrès; B Bussière; M Aubertin

288

The influence of environmental conditions on polysaccharide formation by Ganoderma lucidum in submerged cultures  

Microsoft Academic Search

The effects of environmental parameters on polysaccharide formation by Ganoderma lucidum were investigated in submerged cultures. The optimal temperature and pH was 30–35°C and 4–4·5, respectively, in a glucose-ammonium chloride medium and polysaccharide concentration reached 1·6 mg\\/ml. Agitation and aeration influenced the formation and secretion of polysaccharide. The optimal rotating speed was 150 rpm in 7-day flask cultures, while the

Fan-Chiang Yang; Chun-Bun Liau

1998-01-01

289

Short-haul aviation – under what conditions is it more environmentally benign than the alternatives?  

Microsoft Academic Search

Short-haul aviation is faced with important challenges to its future: airport congestion and security delays reducing its time-competitiveness, steadily increasing fuel price and the likely imposition of carbon taxes eating into its margins. Increasingly, short-haul aviation is demonised by environmental activists and some politicians. However many question whether the alternatives are better, similar or worse, from the point of view

Roger Kemp

2009-01-01

290

Community Structure and Environmental Conditions in Florida Shallow Lakes Dominated by Submerged Aquatic Vegetation  

Microsoft Academic Search

Florida inland waters are dominated by shallow lakes, many of which support the growth of submerged aquatic vegetation (SAV). We examined the species composition and selected environmental variables of SAV-dominated lakes using data from the Florida LAKEWATCH program. Our analysis revealed eight genera with approximately 15 species of SAV among these shallow lakes, which range in size from <2–2,300 ha.

Binhe Gu; Mark V. Hoyer

2005-01-01

291

Behavioural responses of some rocky shore fish exposed to adverse environmental conditions  

Microsoft Academic Search

The behavioural responses of three littoral teleosts, Lipophrys (=Blennus) pholis, Taurulus (= Cottus) bubalis and Ciliata mustella to changing environmental pO2, salinity, temperature, pH and pCO2 were investigated.Both L. pholis and T. bubalis emerge from seawater and climb onto land at low oxygen tensions but only L. pholis is very mobile once out of water; the values inducing emergence are

J. Davenport; A. D. Woolmington

1981-01-01

292

Environmental and Genetic Variation of Soybean Tocopherol Content Under Brazilian Growing Conditions  

Microsoft Academic Search

Information about the chemical composition of soybean cultivars (cvs) and environmental impact on their composition is important\\u000a for processors and exporters to meet the demand of niche markets. Tocopherol composition (?, ?, ?, ?, and total), was analyzed\\u000a in seeds of 89 Brazilian soybean cultivars grown under fertile soil in Ponta Grossa, Paraná state, Brazil, in 2001. A large\\u000a range

Mercedes Concórdia Carrão-Panizzi; Sevim Z. Erhan

2007-01-01

293

Introducing a conditional 'Willingness to Pay' index as a quantifier for environmental impact assessment  

NASA Astrophysics Data System (ADS)

The optimal concentration Copt of a pollutant in the environment can be determined as an equilibrium point in the trade off between (i) environmental cost, due to impact on man/ecosystem/economy, and (ii) economic cost for environmental protection, as it can be expressed by Pigouvian tax. These two conflict variables are internalized within the same techno-economic objective function of total cost, which is minimized. In this work, the first conflict variable is represented by a Willingness To Pay (WTP) index. A methodology is developed for the estimation of this index by using fuzzy sets to count for uncertainty. Implementation of this methodology is presented, concerning odor pollution of air round an olive pomace oil mill. The ASTM E544-99 (2004) 'Standard Practice for Referencing Suprathreshold Odor Intensity' has been modified to serve as a basis for testing, while a network of the quality standards, required for the realization/application of this 'Practice', is also presented. Last, sensitivity analysis of Copt as regards the impact of (i) the increase of environmental information/sensitization and (ii) the decrease of interest rate reveals a shifting of Copt to lower and higher values, respectively; certain positive and negative implications (i.e., shifting of Copt to lower and higher values, respectively) caused by socio-economic parameters are also discussed.

Batzias, Fragiskos; Kopsidas, Odysseas

2012-12-01

294

Homogenization of Environmental Condition and Benthic Communities in Restored Streams of the North Carolina Piedmont.  

NASA Astrophysics Data System (ADS)

Stream ecosystems, as described through benthic communities and twenty environmental variables, exhibited decreased variances and reduced ordinal dimensionality in restored streams when compared to associated upstream reaches in this upstream-downstream investigation of stream restoration in the North Carolina Piedmont. Through paired t-tests of the environmental variables and several descriptions of community structure and function, the variance for restored stream reaches was lower than the upstream reaches for 70% of environmental characteristics, for 75% of Functional Feeding and Habitat Groups, and for all of the community descriptions, including the Q statistic, Shannon Index, Simpson Index, EPT taxa richness, and NCBI. Further, Nonmetric Multidimensional Scaling of the sites best expressed the upstream reaches on three axes, while the restored stream reaches required only one axis to effectively describe variation in the benthic communities. These results suggest that simplification of the biota may occur following steam restoration activities, indicating the biological losses associated with early recovery in these streams. While the science of stream restoration has advanced since the early construction and implementation at these sites, the consequential homogenization demonstrated by these biotic and abiotic stream corridor features emphasizes the importance of a concentrated effort to re-establish heterogeneity in restoration designs.

Tullos, D. D.; Penrose, D. L.; Jennings, G. D.; Wentworth, T. R.

2005-05-01

295

Analysis of the Salmonella typhimurium Proteome through Environmental Response toward Infectious Conditions  

SciTech Connect

Salmonella enterica serovar Typhimurium (aka, S. typhimurium) is a facultative intracellular pathogen that causes ~40,000 reported cases of acute gastroenteritis and diarrhea a year in the United States. To develop a deeper understanding of the infectious state of S. typhimurium, liquid chromatography-mass spectrometry-based “bottom-up” proteomics was used to globally analyze the proteins present under specific growth conditions. Salmonella typhimurium LT2 strain cells were grown in contrasting culture conditions that mimicked both natural free-living conditions and an infectious state, i.e., logarithm phase, stationary phase and Mg-depleted medium growth. Initial comparisons of the LT2 strain protein abundances among cell culture conditions indicate that the majority of proteins do not change significantly. Not unexpectedly, cells grown in Mg-depleted medium conditions had a higher abundance of Mg2+ transport proteins than found in other growth conditions. A second more virulent Salmonella typhimurium strain (14028) was also studied with these growth conditions and used to directly compare to the LT2 strain. The strain comparison offers a unique opportunity to compare and contrast observations in these closely related bacteria. One particular protein family, propanediol utilization proteins, was drastically more abundant in the 14028 strain than in the LT2 strain, and may be a contributor to increased pathogenicity in the 14028 strain.

Adkins, Joshua N.; Mottaz, Heather M.; Norbeck, Angela D.; Gustin, Jean K.; Rue, Joanne; Clauss, Therese RW; Purvine, Samuel O.; Rodland, Karin D.; Heffron, Fred; Smith, Richard D.

2006-08-01

296

Germination and Growth of a Vegetable Exposed to Very Severe Environmental Conditions Experimentally Induced by High Voltage  

NASA Astrophysics Data System (ADS)

Ultra-high-voltage (UHV) transmission power lines are required in order to reduce transmission energy losses, and to transfer more power across long distances. However, the ecological and biological influence of UHV lines has not been documented well. Possible influences of UHV lines are: electro-magnetic field, ozone, NOx, and ion shower. The purpose of this study was to obtain information on the germination and growth of Raphanus sativus L.cv. Kaiware-daikon exposed to an experimental environment in which all the above influences at very severe intensity levels were working simultaneously. Several environmental conditions severer than those predicted for future UHV lines were set up, using a high voltage at 60 Hz. The germination and growth of this plant were suppressed under the experimental conditions used, the suppression being greater the severer the conditions. When the electric field is strong, corona discharge occurs at the tip of the plant.

Aoki, Takashi; Ikezawa, Shunjiro

1982-09-01

297

Productivity and Indoor Environmental Conditions Research: An Annotated Bibliography for Facility Engineers.  

National Technical Information Service (NTIS)

Since the energy crisis in the mid-1970s to the renewed interest in reducing the nation's energy consumption, conservation strategies often have been employed with little regard to their impact on the occupants of the affected buildings. Austere condition...

D. B. Lister E. M. Jenicek P. F. Preissner

1998-01-01

298

Assessment of Fungal Growth on Ceiling Tiles under Environmentally Characterized Conditions.  

National Technical Information Service (NTIS)

The paper discusses investigation of the impact of the building environment on the ability of building materials to support microbial growth, using static chambers with defined relative humidity, temperature, and light conditions. The ability of fungi to ...

K. Foarde P. Dulaney E. Cole D. VanOsdell D. Ensor

1993-01-01

299

Toxicity of Pentachlorophenol to Aquatic Organisms under Naturally Varying and Controlled Environmental Conditions.  

National Technical Information Service (NTIS)

The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty-one acute toxicity tests were...

S. F. Hedtke C. W. West K. N. Allen T. J. Norberg-King D. I. Mount

1986-01-01

300

Optimized Maximum Power Point Tracker for Fast-Changing Environmental Conditions  

Microsoft Academic Search

This paper presents a high-performance maximum power point tracker (MPPT) optimized for fast cloudy conditions, e.g., rapidly changing irradiation on the photovoltaic panels. The rapidly changing conditions are tracked by an optimized hill-climbing MPPT method called dP-P&O. This algorithm separates the effects of the irradiation change from the effect of the tracker's perturbation and uses this information to optimize the

Dezso Sera; Remus Teodorescu; Jochen Hantschel; Michael Knoll

2008-01-01

301

Total environmental warming impact (TEWI) calculations for alternative automative air-conditioning systems  

Microsoft Academic Search

The Montreal Protocol phase-out of chlorofluorocarbons (CFCs) has required manufacturers to develop refrigeration and air-conditioning systems that use refrigerants that can not damage stratospheric ozone. Most refrigeration industries have adapted their designs to use hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFC) refrigerants; new automobile air- conditioning systems use HFC-134a. These industries are now being affected by scientific investigations of greenhouse warming and

J. R. Sand; S. K. Fischer

1997-01-01

302

Visible/Near-Infrared Hyperspectral Sensing of Solids under Controlled Environmental Conditions  

SciTech Connect

We describe the use of a wind tunnel for conducting controlled passive hyperspectral imaging experiments. Passive techniques are potentially useful for detecting explosives, solid-phase chemicals and other materials of interest from a distance so as to provide operator safety. The Pacific Northwest National Laboratory operates a wind tunnel facility that can generate and circulate artificial atmospheres to control lighting, humidity, temperature, aerosol burdens, and obscurants. We will present recent results describing optimized sensing of solids over tens of meters distance using both visible and near-infrared cameras, as well as the effects of certain environmental parameters on data retrieval.

Bernacki, Bruce E.; Anheier, Norman C.; Mendoza, Albert; Fritz, Brad G.; Johnson, Timothy J.

2011-06-01

303

Immunization and facilitation produced by predictable and controllable aversive events alternating with different duration unpredictable and uncontrollable aversive events  

Microsoft Academic Search

This investigation examined whether immunization to learned helplessness is more effective through predictable and controllable events alternating with inescapable and unpredictable events of different duration, than through experiences with only controllable and predictable events. Prior experience with intermittent success resulted in greater immunization than experience with consistent success. Forty?two male Wistar rats were distributed at random to one of the

Francisco Vicente; Pilar Ferrándiz

2006-01-01

304

Keep looking ahead? Redirection of visual fixation does not always occur during an unpredictable obstacle avoidance task  

Microsoft Academic Search

Visual information about the environment, especially fixation of key objects such as obstacles, is critical for safe locomotion. However, in unpredictable situations where an obstacle suddenly appears it is not known whether central vision of the obstacle and\\/or landing area is required or if peripheral vision is sufficient. We examined whether there is a re-direction of visual fixation from an

Daniel S. Marigold; Vivian Weerdesteyn; Aftab E. Patla; Jacques Duysens

2007-01-01

305

Effect of chronic unpredictable mild stress on brain–pancreas relative protein in rat brain and pancreas  

Microsoft Academic Search

Brain–pancreas relative protein (BPRP) is a novel protein whose biological function remains unknown. Here, we report a possible role of BPRP in male rats exposed to chronic unpredictable mild stress (CUMS) to induce depression for 3 weeks. Compared to unstressed rats, those exposed to CUMS showed significantly less weight gain with age, decreased consumption of (and preference for) sucrose without

Yan-Hua Lin; Ai-Hua Liu; Ying Xu; Lu Tie; He-Ming Yu; Xue-Jun Li

2005-01-01

306

Efficacy of antiseptics and disinfectants on clinical and environmental yeast isolates in planktonic and biofilm conditions.  

PubMed

The aim of this study was to evaluate the efficacy of five antiseptics, three surface disinfectants and UV radiation against a wide range of clinical and environmental yeast isolates. Their efficacy against pure cultures, yeast mixtures and biofilms (prepared by culturing yeasts in Sabouraud broth containing a final concentration of 8% glucose) was tested. Three clinical isolates of Candida albicans, Cryptococcus neoformans and Rhodotorula rubra, and two environmental isolates of Candida albicans and Cryptococcus uniguttulatus were selected. For seven out of eight biocides tested (Betadine, Dermacide, Chlorhexidine, Dosisepsine, hydrogen peroxide, sodium hypochlorite, 70% alcohol, 0.5% Ecodiol) and for UV radiation, susceptibility did not differ according to genus, species or origin. Hydrogen peroxide, 0.25% Ecodiol and UV radiation were ineffective against the five isolates tested. On pure planktonic cultures, and, to a lesser extent, on free-living yeast mixtures, the other products were active and were then tested against biofilms: eight out of nine biocides were ineffective. Chlorhexidine at 0.5% was the only fungicidal agent on pure cultures, yeast mixtures and biofilms. The importance of the test method, including agent concentration, is discussed. PMID:15358824

Théraud, M; Bédouin, Y; Guiguen, C; Gangneux, J-P

2004-10-01

307

Sunna 535-nm photo-fluorescent film dosimeter response to different environmental conditions  

NASA Astrophysics Data System (ADS)

Evaluations on the influence of environmental variabilities on the red fluorescence component of the Sunna Model ? photo-fluorescent dosimeterTM have previously been reported. This present paper describes the environmental effects on the response of the green fluorescence component of the same dosimeter, which is manufactured using the injection molding technique. The results presented include temperature, relative humidity, and light influences both during and after irradiation. The green fluorescence signal shows a significant dependence on irradiation temperature below room temperature at 1%/°C. Above room temperature (approximately 24-60°C), the irradiation temperature effect varies from -0.1%/°C to 1.0%/°C, depending on the absorbed dose level. For facilities with irradiation temperatures between 30°C and 60°C and absorbed dose levels above 10kGy, irradiation temperature effects are minimal. Light-effects results indicate that the dosimeter is influenced by ultraviolet and blue wavelengths during irradiation as well as during the post-irradiation stabilization period (approximately 22h), requiring the use of light-tight packaging. Results also show that the dosimeter exhibits negligible effects from ambient moisture during and after irradiation when in the range of 33-95% relative humidity.

Murphy, M. K.; Kovács, A.; McLaughlin, W. L.; Miller, S. D.; Puhl, J. M.

2003-12-01

308

Urban Tree Species Show the Same Hydraulic Response to Vapor Pressure Deficit across Varying Tree Size and Environmental Conditions  

PubMed Central

Background The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations. Methodology/Principal Findings We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP). The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1) the influence of tree species and size on transpiration, and 2) the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH) and tree canopy transpiration amount (Ec) was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between Gc at VPD?=?1 kPa (Gcref) and the Gc sensitivity to VPD (?dGc/dlnVPD) across studied species as well as under contrasting soil water and Rs conditions in the urban area. Conclusions/Significance We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of Gcref.

Chen, Lixin; Zhang, Zhiqiang; Ewers, Brent E.

2012-01-01

309

Histone tail acetylation in brain occurs in an unpredictable fashion after death.  

PubMed

Histone acetylation plays a role in the regulation of gene transcription. Yet it is not known whether post-mortem brain tissue is suitable for the analysis of histone acetylation. To examine this question, nucleosomes were isolated from frontal cortex of nine subjects which were obtained at short times after death and immediately frozen at -80°C or maintained at room temperature from 3 h up to 50 h after death and then frozen at -80°C to mimic variable post-mortem delay in tissue processing as currently occurs in normal practice. Chromatin immunoprecipitation assays were performed for two lysine residues, H3K9ac and H3K27ac. Four gene loci were amplified by SyBrGreen PCR: Adenosine A(2A) receptor, UCHL1, ?-synuclein and ?-globin. Results showed variability in the histone acetylation level along the post-mortem times and an increase in the acetylation level at an unpredictable time from one case to another and from one gene to another within the first 24 h of post-mortem delay. Similar results were found with three rat brains used to exclude the effects of agonal state and to normalize the start-point as real time zero. Therefore, the present observations show that human post-mortem brain is probably not suitable for comparative studies of histone acetylation. PMID:21922206

Barrachina, Marta; Moreno, Jesús; Villar-Menéndez, Izaskun; Juvés, Salvador; Ferrer, Isidre

2011-09-16

310

Disease and thermal acclimation in a more variable and unpredictable climate  

NASA Astrophysics Data System (ADS)

Global climate change is shifting the distribution of infectious diseases of humans and wildlife with potential adverse consequences for disease control. As well as increasing mean temperatures, climate change is expected to increase climate variability, making climate less predictable. However, few empirical or theoretical studies have considered the effects of climate variability or predictability on disease, despite it being likely that hosts and parasites will have differential responses to climatic shifts. Here we present a theoretical framework for how temperature variation and its predictability influence disease risk by affecting host and parasite acclimation responses. Laboratory experiments conducted in 80 independent incubators, and field data on disease-associated frog declines in Latin America, support the framework and provide evidence that unpredictable temperature fluctuations, on both monthly and diurnal timescales, decrease frog resistance to the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Furthermore, the pattern of temperature-dependent growth of the fungus on frogs was opposite to the pattern of growth in culture, emphasizing the importance of accounting for the host-parasite interaction when predicting climate-dependent disease dynamics. If similar acclimation responses influence other host-parasite systems, as seems likely, then present models, which generally ignore small-scale temporal variability in climate, might provide poor predictions for climate effects on disease.

Raffel, Thomas R.; Romansic, John M.; Halstead, Neal T.; McMahon, Taegan A.; Venesky, Matthew D.; Rohr, Jason R.

2013-02-01

311

Antidepressant-like effect of flaxseed secoisolariciresinol diglycoside in ovariectomized mice subjected to unpredictable chronic stress.  

PubMed

Secoisolariciresinol diglycoside (SDG), a predominant lignan in flaxseed, has antioxidant activity as a dietary supplement. The purpose of the present study was to investigate the antidepressant-like effect and the possible mechanism of flaxseed SDG when the ovariectomized mice were exposed to the unpredictable chronic mild stress procedure. Chronic stress induced the increases in immobility time in mouse model of despair tests, but administration with SDG (80 and 160 mg/kg, p.o.) for 21 days inhibited these behavioral changes caused by stress in both forced swimming and tail suspension tests. These doses that affected the immobile response did not affect locomotor activity. Moreover, the changes in the serum corticosterone and adrenocorticotropic hormone (ACTH) levels were also measured to explore the SDG-associated regulation of hypothalamus-pituitary-adrenals (HPA) axis. The results indicated that the chronic stress-induced increases in the serum corticosterone and ACTH were reversed by treatment with high doses of SDG. Chronic treatment with SDG also affected the body weight of mice and IL-6, IL1? levels in the frontal cortex. In addition, chronic stress procedure induced a decrease in brain-derived neurotrophic factor (BDNF) expression in the frontal cortex of mice; while treatment with SDG reversed this reduction of BDNF. All these results provide compelling evidence that the behavioral effects of flaxseed SDG in the ovariectomized mice might be related to their modulating effects on the neuroendocrine-immune network and neurotrophin factor expression. PMID:23263992

Ma, Xing; Wang, Rui; Zhao, Xin; Zhang, Chong; Sun, Jiao; Li, Jianxin; Zhang, Lu; Shao, Tuo; Ruan, Lina; Chen, Liang; Xu, Ying; Pan, Jianchun

2012-12-22

312

Adaptive Bloom Filter: A Space-Efficient Counting Algorithm for Unpredictable Network Traffic  

NASA Astrophysics Data System (ADS)

The Bloom Filter (BF), a space-and-time-efficient hashcoding method, is used as one of the fundamental modules in several network processing algorithms and applications such as route lookups, cache hits, packet classification, per-flow state management or network monitoring. BF is a simple space-efficient randomized data structure used to represent a data set in order to support membership queries. However, BF generates false positives, and cannot count the number of distinct elements. A counting Bloom Filter (CBF) can count the number of distinct elements, but CBF needs more space than BF. We propose an alternative data structure of CBF, and we called this structure an Adaptive Bloom Filter (ABF). Although ABF uses the same-sized bit-vector used in BF, the number of hash functions employed by ABF is dynamically changed to record the number of appearances of a each key element. Considering the hash collisions, the multiplicity of a each key element on ABF can be estimated from the number of hash functions used to decode the membership of the each key element. Although ABF can realize the same functionality as CBF, ABF requires the same memory size as BF. We describe the construction of ABF and IABF (Improved ABF), and provide a mathematical analysis and simulation using Zipf's distribution. Finally, we show that ABF can be used for an unpredictable data set such as real network traffic.

Matsumoto, Yoshihide; Hazeyama, Hiroaki; Kadobayashi, Youki

313

The role of genotypic diversity in determining grassland community structure under constant environmental conditions  

Microsoft Academic Search

Summary 1. A recent experiment varied the genetic diversity of model grassland communities under standardized soil and management conditions and at constant initial species diversity. After 5 years' growth, genetically diverse communities retained more species diversity and became more similar in species composition than genetically impover- ished communities. 2. Here we present the results of further investigation within this experimental

RAJ WHITLOCK; J. PHILIP GRIME; ROSEMARY BOOTH; TERRY BURKE

2007-01-01

314

INTERACTIONS AMONG ENVIRONMENTAL STRESS, BODY CONDITION, NUTRITIONAL STATUS, AND DOMINANCE IN GREAT TITS  

Microsoft Academic Search

We studied body condition and feather growth rate in Great Tits (Parus major) in relation to dominance in two localities during late autumn and early winter. The two lo- calities differed in elevation, ambient temperature, and arthropod availability. We supple- mented the two study areas with food (husked peanuts) throughout the study period. The percentage of time tits spent at

M. CARRASCAL; JUAN CARLOS SENAR; INGRID MOZETICH; FRANSEC URIBE; JORDI DOMENECH

315

Creep-rupture life of Douglas-fir under cyclic environmental conditions  

Microsoft Academic Search

Small beams of Douglas-fir were subjected to constant loads and the time to failure was investigated while the specimens were subjected to cyclicly varying conditions of relative humidity and temperature. At a given load level, periodic variations in environment led to significant reductions in the average time to failure. The extent ofthis reduction was primarily related to the range in

Arno P. Schniewind

1967-01-01

316

Correlation between Environmental Conditions and the Distribution of Mosses Exposed to Urban Air Pollutants  

Microsoft Academic Search

Moss surveys have several advantages over conventional depositionmonitoring based on precipitation, and allow the study of regional differences and temporal trends of airborne pollution. The purposes of this study were to: (i) describe the moss species growing in one of the largest industrial cities in Asia, (ii) document edaphic and atmospheric conditions at each site, (iii) collect materials and data

Joohyoung Lee; Perry Johnson-Green; Eun Ju Lee

2004-01-01

317

Test of Dynamic Properties in Different Environmental Conditions with Different Occupant Weight  

Microsoft Academic Search

This paper deals with accelerated aging of different vehicle segment foams such as high and low density passenger cars and truck cushions. These different segments have different durability, density, firmness, and thickness requirements in many cases. This paper explores the difference in vehicle environment, accelerated aging conditions, and the numbers of fatigue cycles, then provides experimental methods to determine complete

James T. McEvoy; Terry McRoberts; Ryoko Yamasaki

2004-01-01

318

Emissions and environmental impacts from air-conditioning and refrigeration systems  

Microsoft Academic Search

The impacts of air conditioning and refrigeration systems on stratospheric ozone are primarily linked to release of ozone-depleting refrigerants. Their contributions to global warming stem both from release of refrigerants and from emission of greenhouse gases (GHGs) for associated energy use. Because the energy-related component has a significantly higher warming impact, phaseout of hydrofluorocarbon (HFC) refrigerants with less efficient options

James M. Calm

2002-01-01

319

Superior performance of African runners in warm humid but not in cool environmental conditions.  

PubMed

The purpose of this study was to examine the running performances and associated thermoregulatory responses of African and Caucasian runners in cool and warm conditions. On two separate occasions, 12 (n = 6 African, n = 6 Caucasian) well-trained men ran on a motorized treadmill at 70% of peak treadmill running velocity for 30 min followed by an 8-km self-paced performance run (PR) in cool (15 degrees C) or warm (35 degrees C) humid (60% relative humidity) conditions. Time to complete the PR in the cool condition was not different between groups ( approximately 27 min) but was significantly longer in warm conditions for Caucasian (33.0 +/- 1.6 min) vs. African (29.7 +/- 2.3 min, P < 0.01) runners. Rectal temperatures were not different between groups but were higher during warm compared with cool conditions. During the 8-km PR, sweat rates for Africans (25.3 +/- 2.3 ml/min) were lower compared with Caucasians (32.2 +/- 4.1 ml/min; P < 0.01). Relative rates of heat production were less for Africans than Caucasians in the heat. The finding that African runners ran faster only in the heat despite similar thermoregulatory responses as Caucasian runners suggests that the larger Caucasians reduce their running speed to ensure an optimal rate of heat storage without developing dangerous hyperthermia. According to this model, the superior running performance in the heat of these African runners can be partly attributed to their smaller size and hence their capacity to run faster in the heat while storing heat at the same rate as heavier Caucasian runners. PMID:12949014

Marino, Frank E; Lambert, Mike I; Noakes, Timothy D

2003-08-29

320

Overview of environmental and hydrogeologic conditions at McGrath, Alaska  

USGS Publications Warehouse

The remote village of McGrath along the Kuskokwim River in southwestern Alaska has long cold winters and short summers. The village is located on the flood plain of the Kuskokwim River and obtains drinking water for its 533 residents from the Kuskokwim River. Surface spills and disposal of hazardous materials combined with frequent flooding of the Kuskokwim River could affect the quality of the drinking water. Alternative drinking-water sources are available but at greater cost than existing supplies. The Federal Aviation Administration (FAA) owns or operates airport support facilities in McGrath and wishes to consider the subsistence lifestyle of the residents and the quality of the current environ- ment when evaluating options for remediation of environmental contamination at their facilities. This report describes the history, socioeconomics, physical setting, ground- and surface-water hydrology, geology, climate, vegetation, soils, and flood potential of the areas surrounding the FAA facilities near McGrath.

Dorava, J. M.

1994-01-01

321

Assessing the environmental impact of biobleaching: effects of the operational conditions.  

PubMed

The environmental impact of enzyme bleaching stages applied to oxygen-delignified eucalypt kraft pulp was assessed via the chemical oxygen demand (COD), color, absorbance spectrum, residual enzyme activity and Microtox toxicity of the effluents from a laccase-HBT (1-hydoxybenzotriazole) treatment. The influence of the laccase and HBT doses, and reaction time, on these effluent properties was also examined. The laccase dose was found to be the individual variable most strongly affecting COD, whereas the oxidized form of HBT was the main source of increased color and toxicity in the effluents. Moreover, it inactivated the enzyme. Oxidation of the mediator was very fast and essentially dependent on the laccase dose. Using the laccase-mediator treatment after a xylanase stage improved pulp properties without affecting effluent properties. This result holds great promise with a view to the industrial implementation of biobleaching sequences involving the two enzymes in the future. PMID:22079687

Valls, Cristina; Quintana, Elisabet; Roncero, M Blanca

2011-10-20

322

Analysis of the Salmonella typhimurium Proteome through Environmental Response toward Infectious Conditions  

Microsoft Academic Search

Salmonella enterica serovar Typhimurium (aka, S. typhimurium) is a facultative intracellular pathogen that causes ~40,000 reported cases of acute gastroenteritis and diarrhea a year in the United States. To develop a deeper understanding of the infectious state of S. typhimurium, liquid chromatography-mass spectrometry-based âbottom-up❠proteomics was used to globally analyze the proteins present under specific growth conditions. Salmonella typhimurium LT2

Joshua N. Adkins; Heather M. Mottaz; Angela D. Norbeck; Jean K. Gustin; Joanne Rue; Therese R. W. Clauss; Samuel O. Purvine; Karin D. Rodland; Fred Heffron; Richard D. Smith

2006-01-01

323

Improving Casuarina growth and symbiosis with Frankia under different soil and environmental conditions—review  

Microsoft Academic Search

Casuarinas are very important plants for their various uses and survival in adverse sites or harsh environments. As nitrogen\\u000a fixation, in symbiosis with Frankia, is an important factor for the survival of these plants under various conditions, the basis for selecting both effective\\u000a and tolerant Frankia strains and Casuarina spp., are provided. Enhancement of the symbiotic relationship between Frankia and

W. F. Sayed

2011-01-01

324

Microbial Diversity During Cellulose Decomposition in Different Forest Stands: I. Microbial Communities and Environmental Conditions  

Microsoft Academic Search

We studied the effect of forest tree species on a community of decomposers that colonize cellulose strips. Both fungal and\\u000a bacterial communities were targeted in a native forest dominated by beech and oak and 30-year-old beech and spruce plantations,\\u000a growing in similar ecological conditions in the Breuil-Chenue experimental forest site in Morvan (France). Microbial ingrowths\\u000a from the 3rd to 10th

Ariana Kubartová; Judicaël Moukoumi; Thierry Béguiristain; Jacques Ranger; Jacques Berthelin

2007-01-01

325

Simulation of the environmental climate conditions on martian surface and its effect on Deinococcus radiodurans  

Microsoft Academic Search

The resistance of terrestrial microorganisms under the thermo-physical conditions of Mars (diurnal temperature variations, UV climate, atmospheric pressure and gas composition) at mid-latitudes was studied for the understanding and assessment of potential life processes on Mars. In order to accomplish a targeted search for life on other planets, e.g. Mars, it is necessary to know the limiting physical and chemical

U. Pogoda de la Vega; P. Rettberg; G. Reitz

2007-01-01

326

[Fundamentals of socio-hygienic monitoring of environmental conditions for students of higher education schools].  

PubMed

Socioeconomic transformations and the poor environment of an industrial megalopolis negatively affected quality of life and morbidity rates in students (n = 2160). Academic intensity contributed to an increase in overall morbidity and morbidity from nervous system involvement. The regional sociohygienic monitoring of high-school training conditions within the framework of the surveillance system substantiates programs to prevent worse health and life quality in high school students. PMID:22712322

Blinova, E G; Kuchma, V R

327

Monitoring and Prevention of Anemia Relying on Nutrition and Environmental Conditions in Sports  

PubMed Central

Conflict of interest: none declared. Introduction Anemia is a blood disorder characterized by abnormally low levels of healthy red blood cells or reduced hemoglobin, the iron-bearing protein in red blood cells that delivers oxygen to tissues throughout the body. The most common symptoms of this disorder are fatigue, weakness and, in extreme cases, shortness of breath or palpitations, or you may have no symptoms at all. Sports anemia is a term loosely applied to a least three different conditions: hemodilution, iron deficiency anemia and foot-strike anemia. Not exclusive to athletes, iron deficiency anemia occurs most often among women who may lose more iron each month when they menstruate than they take in. Material and Methods Therefore, we examined its effect on the physical condition of female athletes. Several years (since 2010th until 2012th), we studied how anemia among girls (pioneers, juniors and seniors categories) that are involved in sports (women’s soccer, volleyball and handball) in Rasina’s district (Serbia), affecting their physical fitness. When their trainers approach to us, complaining that they have players who are great, so extraordinary talents, but by no means able to withstand more than twenty minutes in the game, we suggest them to perform laboratory tests. It was tested 134th female athletes. Results and Discussion Anemia was observed in 43. (9. pioneers, 19. juniors and 15. seniors). So, laboratory results showed that in these girls anemia causes poor sport condition. After that, the girls enhanced nutrition. Their diet consisted of iron supplements and vitamins. Altitude training was organized for them, also. After all these treatments, condition significantly improved. It was first time that trainers in Rasina’s district realizing significance of laboratory tests.

Sacirovic, Selim; Asotic, Jasminka; Maksimovic, Radmila; Radevic, Borislav; Muric, Benin; Mekic, Hasim; Biocanin, Rade

2013-01-01

328

Effects of Cool and Hot Humid Environmental Conditions on Neuroendocrine Responses of Horses to Treadmill Exercise  

Microsoft Academic Search

To determine the effects of exercise, high heat and humidity and acclimation on plasma adrenaline, noradrenaline, ?-endorphin and cortisol concentrations, five horses performed a competition exercise test (CET; designed to simulate the speed and endurance test of a three-day event) in cool dry (CD) (20°C\\/40% RH) and hot humid (30°C\\/80% RH) conditions before (pre-acclimation) and after (post-acclimation) a 15 day

R. J. Williams; D. J. Marlin; N. Smith; R. C. Harris; W. Haresign; M. C. Davies Morel

2002-01-01

329

Carbon residence times obtained from labelled ryegrass decomposition in soils under contrasting environmental conditions  

Microsoft Academic Search

The rate of decomposition of ryegrass in New Zealand soils was studied. Six soils from contrasting New Zealand environments were amended with 14C-labelled ryegrass (Lolium hybridum Hausskn), which was allowed to decompose in micro-lysimeters under field conditions for 2 yr. Periodically, the micro-lysimeters were destructively sampled, and the amount of 14C remaining in the soil and the fraction of 14C

A. Parshotam; S. Saggar; P. L. Searle; B. K. Daly; G. P. Sparling; R. L. Parfitt

2000-01-01

330

Effect of environmental conditions on observed, modeled, and assimilated sea ice motion errors  

NASA Astrophysics Data System (ADS)

Previous evaluations of ice motion have primarily consisted of comparisons with in situ observations and general sensitivity studies with wind speed and direction. An assimilation framework allows the quality of ice motions to be studied as an explicit function of model and model forcing parameters. Here we investigate the effects of local conditions on remotely sensed, modeled, and assimilated motions. We use local conditions, as given by the ice model, to examine ice motion errors based on (1) proximity to the coast, (2) ice thickness, and (3) wind-forcing. In comparison with buoy observations, both modeled and remotely sensed ice motions have lowest errors in moderately thick ice, in low winds, and away from coastal regions. Wind speed plays the largest role in the errors, and higher winds speeds lead to substantially higher motion error standard deviation. However, higher wind speeds also increase the correlation of modeled and remotely sensed motions with buoy observations. An optimal interpolation assimilation methodology, which led to substantial improvements in ice motion quality on a regional and seasonal basis, was employed in this study. Assimilation improved the quality of the ice motions (lower error, higher correlation) throughout most ranges of wind speed and ice thickness and both near the coast and in the central ice pack. This study suggests that adjusting assimilation weights based on local model conditions could efficiently yield even higher quality assimilated motion fields.

Meier, Walter N.; Maslanik, James A.

2003-05-01

331

Environmental conditions in the Donggi Cona lake catchment, NE Tibetan Plateau, based on factor analysis of geochemical data  

NASA Astrophysics Data System (ADS)

We present a methodological approach for the characterization of spatial variations of environmental and transport conditions based on geochemical data. We analyzed the geochemical characteristics of terrestrial sediments on an alluvial fan and adjacent areas in the eastern part of the Donggi Cona catchment. The geochemical characteristics of the sediment samples were measured using X-ray fluorescence spectroscopy. A factor model based on nine elements (Sr, Rb, Zn, Fe, Mn, V, Ti, Ca and K) gave the best results using factor analysis. Our results show that factor analysis of geochemical data can explain spatial variations in the catchment, even within a relatively small area with more or less constant climatological conditions.The four most important factors of our model explain 68.4% of the total variance within the dataset. The four factors represent a carbonate, weathering and two redox condition signals, respectively. The spatial distribution of factor loadings points to regions with specific environmental conditions. These regions show a certain carbonate input or production (factor 1), specific weathering rates (factor 2) or specific redox conditions (factors 3 and 4). The factor loadings of the first and second factor are used to reclassify the data into four groups, being dune, loess, lake and fluvial gravel sediments. This reclassification confirms or improves the prior field classification in 70% of all cases. For 23% of the samples, the model gave a different interpretation. The factor loadings in these cases represent the origin of the material rather than its present sediment type, thereby giving valuable information about sediment provenance. Since the third and fourth factor seem more dependent on location, they do not differentiate between different sediment types.Multivariate statistics of the geochemistry of terrestrial sediments (i) allows the subdivision of samples into different sediment types, (ii) indicates dominant regions for weathering, carbonate production and manganese washout and (iii) gives suggestions about the provenance of the sediments. This is the first detailed study of geochemical parameters on the Tibetan Plateau not focusing on lake cores, resulting in a spatial characterization of the local geochemistry. This gives insight in the sediment transport connections between the catchment and the lake, illustrating the value of terrestrial sediments as additional indicator of environmental variations.

IJmker, Janneke; Stauch, Georg; Hartmann, Kai; Diekmann, Bernhard; Dietze, Elisabeth; Opitz, Stephan; Wünnemann, Bernd; Lehmkuhl, Frank

2012-01-01

332

The effect of environmental conditions on expression of Bacteroides fragilis and Bacteroides thetaiotaomicron C10 protease genes  

PubMed Central

Background Bacteroides fragilis and Bacteroides thetaiotaomicron are members of the normal human intestinal microbiota. However, both organisms are capable of causing opportunistic infections, during which the environmental conditions to which the bacteria are exposed change dramatically. To further explore their potential for contributing to infection, we have characterized the expression in B. thetaiotaomicron of four homologues of the gene encoding the C10 cysteine protease SpeB, a potent extracellular virulence factor produced by Streptococcus pyogenes. Results We identified a paralogous set of genes (btp genes) in the B. thetaiotaomicron genome, that were related to C10 protease genes we recently identified in B. fragilis. Similar to C10 proteases found in B. fragilis, three of the B. thetaiotaomicron homologues were transcriptionally coupled to genes encoding small proteins that are similar in structural architecture to Staphostatins, protease inhibitors associated with Staphopains in Staphylococcus aureus. The expression of genes for these C10 proteases in both B. fragilis and B. thetaiotaomicron was found to be regulated by environmental stimuli, in particular by exposure to oxygen, which may be important for their contribution to the development of opportunistic infections. Conclusions Genes encoding C10 proteases are increasingly identified in operons which also contain genes encoding proteins homologous to protease inhibitors. The Bacteroides C10 protease gene expression levels are responsive to different environmental stimuli suggesting they may have distinct roles in the bacterial-host interaction.

2012-01-01

333

A comparison of modern and fossil ostracods from Frasassi Cave system (northeastern Apennines, Italy) to infer past environmental conditions  

NASA Astrophysics Data System (ADS)

Cave water and sediments from an extensive sulfidic, chemioautotrophic subterranean ecosystem in the hypogenic karst complex of Frasassi (northeastern Apennines of Italy) was analysed for modern and fossil ostracode assemblages. 22 extant and 16 extinct ostracode species make of this continental sulphidic ecosystem one of the richest worldwide. Both modern and fossil assemblages show the expected pattern of species diversity after the simulation procedure for taxonomic distinctness, which indicates no major extinction events since the Pleistocene. Extant species display patchy distribution according to habitat heterogeneity within the sulphidic environment. Fossil assemblages from a 3 m thick fluvial deposit trapped near the entrance of the Caverna del Carbone (CDC) at about 30 m above present river level, and a fine sand deposit resting at about the same elevation in Sala Duecento (SDS) within the Grotta Grande del Vento preliminarily dated with OSL at 111±17 ka are being investigated. The former deposit has yet to be dated but it represents probably a normal stratigraphic succession spanning a few tens of kyr, which was deposited when the cave entrance was at the reach of fluvial flooding, potentially recording the transition from the last interglacial Riss-Würm to the glacial Würm. Sediment samples from the SDS site yielded an ostracode assemblage represented by 12 species with a d18O signature of -5‰ and a well-diversified palinoflora assemblage indicating a transitional condition between steppe and temperate forest. The top sediment from the CDC site is characterized by a less diversified ostracode assemblage represented by 8 species, d18O of -3‰, and a poorly diversified palinoflora dominated by herbaceous plants and lesser pines, indicating a colder environment in the early stage of the last glacial. Additional information on the geometric morphometry approach of B-splines method applied to extant and fossil specimens of the hypogean Mixtacandona ostracode was used to identify microevolutionary patterns and environmentally cued variation. Analyses indicate the presence of one morphotype of a new species A of the group Mixtacandona riongessa, and three distinctive morphotypes of a species B of the group M. laisi-chappuisi occurring in stratigraphically distinct fluvial-cave sediments. Apparent difference in the disparity level between these species could be associated with their survival in different environmental conditions. Species A is found nowadays living exclusively in sulphidic cave waters, and was present in the system since at least the end of the last interglacial. The extraordinary high taxonomic and morphological diversity of ostracods reflects in situ evolutionary processes that have occurred under the cumulative effect of high environmental energy availability of subterranean sulphidic ecosystems, heterogeneous environmental conditions, and spatial and temporal isolation.

Iepure, S.; Namiotko, T.; Montanari, A.; Brugiapaglia, E.; Mainiero, M.; Mariani, S.; Fiebig, M.

2012-04-01

334

Environmental contamination with Mycobacterium avium subspecies paratuberculosis within and around a dairy barn under experimental conditions.  

PubMed

To establish environmental contamination in and around a dairy barn, cows shedding Mycobacterium avium ssp. paratuberculosis (MAP) were housed in a freestall barn. Fecal samples were collected 15 times at 3-wk intervals, and samples of all animals were cultured by using the Trek Diagnostic Systems culture system (Cleveland, OH) to quantify levels of MAP shedding. In parallel, air and floor dust samples were collected inside and outside the experimental farm and analyzed by IS900 real-time PCR for the presence of MAP DNA. Inside the barn, MAP was detected with equal frequency in samples directly contaminated with feces compared with air dust samples above animal level and in dust samples of the corridor. Dust samples collected within the barn were positive more frequently than outside samples, with exception of the outside sample from the farmer's doormat. The risk of MAP exposure was distributed evenly within the dairy barn. Additionally, footwear should be considered as a high-risk fomite for dispersion of dust-related MAP outside the barn. Prevention of MAP exposure in youngstock may require housing of youngstock in separate barns as an additional management measure. PMID:22939786

Eisenberg, S W F; Nielen, M; Hoeboer, J; Rutten, V; Heederik, D; Koets, A P

2012-08-29

335

Kinetics of copper accumulation in Lessonia nigrescens (Phaeophyceae) under conditions of environmental oxidative stress.  

PubMed

Juvenile individuals of the brown kelp Lessonia nigrescens were exposed to a coastal environment chronically impacted by copper mine wastes and currently displaying more than 250 nM of total dissolved copper. The kinetic of copper accumulation in the intra and extracellular compartments was determined and correlated to the oxidative burst resulting from copper-mediated oxidative stress. Accumulation involved an initial adsorption onto the outer cell wall followed by a slower uptake into the cells. A linear pattern of copper uptake over time was found during the first 52 h of exposure, and a steady state was reached at 76 h. The resulting oxidative stress was found to be inefficiently attenuated, and the intracellular level of copper remained sufficiently high to determine a persistently higher than normal level of reactive oxygen species (ROS). Thus, our results strongly suggest that, in L. nigrescens, copper needs to reach an intracellular threshold before oxidative burst develops. Furthermore, it was found that the high ROS levels generated by copper accumulation within the cells persists after the oxidative burst has ceased, suggesting a limited capacity of the algal tissue to buffer the increases of ROS caused by the environmental copper levels. PMID:16737743

Andrade, Santiago; Contreras, Loretto; Moffett, James W; Correa, Juan A

2006-05-01

336

Variations of vessel diameter and ?13C in false rings of Arbutus unedo L. reflect different environmental conditions.  

PubMed

Woody species in Mediterranean ecosystems form intra-annual density fluctuations (IADFs) in tree rings in response to changes in environmental conditions, especially water availability. Dendrochronology, quantitative wood anatomy and high-resolution isotopic analysis (using a laser ablation technique) were used to characterize IADFs in Arbutus unedo shrubs grown on two sites with different water availability on the island of Elba (Italy). Our findings show that IADF characterization can provide information about the relationship between environmental factors and tree growth at the seasonal level. At the more xeric site, IADFs mainly located in the early and middle parts of the annual ring, showed a decrease in vessel size and an increase in ?(13) C as a result of drought deficit. Opposite trends were found at the more mesic site, with IADFs located at the end of the ring and associated with a lower ?(13) C. Moreover, at the first site, IADFs are induced by drought deficit, while at the second site IADFs are linked with the regrowth in the last part of the growing season triggered by favourable wet conditions. This combined approach is a promising way for dating problematic wood samples and interpreting the phenomena that trigger the formation of IADFs in the Mediterranean environment. PMID:20840507

Battipaglia, Giovanna; De Micco, Veronica; Brand, Willi A; Linke, Petra; Aronne, Giovanna; Saurer, Matthias; Cherubini, Paolo

2010-09-14

337

[The environmental conditions of the Kavkazskie Mineralnye Vody (Caucasian Mineral Waters) health resort region, methods for their monitoring and improvement].  

PubMed

This paper describes the unique environmental conditions of the Kavkazskie Mineralnye Vody (Caucasian Mineral Waters) health resort region with special reference to its paramount importance for the national interests of Russia. It is emphasized, however, that the environmental conditions in the region under consideration are far from being satisfactory. In connection with this, the authors point out to the necessity of expanding areas of protective forest stands and prohibition of the implementation of new building projects in the frontal mountain sanitary zones; they draw special attention to the potential danger of degradation of mineral water springs under the influence of changes in the distribution of vertical hydraulic gradients in the upper part of the lithosphere leading to the deterioration of their composition and the contamination of ground and surface waters with municipal and domestic effluents. Special attention is given to the harm and impermissibility of illegal extraction of mineral waters from producing wells. An original method for water quality control and estimation of the optimal production rate is proposed. The authors hypothesize the possible causes behind the discontinuation of mud formation at the Tambukan deposits and substantiate the necessity of using the resource-saving technologies for processing raw materials and urgent measures to eliminate the factors responsible for desalination and pollution of this mineral mud lake. It is concluded that strict state control should be exercised in the region by means of the introduction of the multilevel automated information system for round-the-clock environmental monitoring. The authors believe that only joint efforts of scientists, legislative and executive authorities can preserve Kavkazskie Mineralnye Vody health resort region for the future generations. PMID:23210368

Evseeva, M M; Rud', N Iu; Pershin, I M

338

Galvanic protection distance of zinc-coated steels under various environmental conditions  

SciTech Connect

Galvanic action between zinc and steel is an important property that contributes to the high corrosion resistance of zinc-coated steels. Quantitative knowledge of the galvanic throwing power (i.e., the area of the steel surface that is not covered with zinc but is galvanically protected by the coating in the surrounding area) is of practical importance to the effective application of zinc-coated steel products. The present investigation reported results of a study of the galvanic protection distance determined for the steel/zinc galvanic couple under various laboratory and field conditions.

Zhang, X.G.

2000-02-01

339

Biological and Environmental Initial Conditions Shape the Trajectories of Cognitive and Social-Emotional Development across the First Years of Life  

ERIC Educational Resources Information Center

|Human development is thought to evolve from the dynamic interchange of biological dispositions and environmental provisions; yet the effects of specific biological and environmental birth conditions on the trajectories of cognitive and social-emotional growth have rarely been studied. We observed 126 children at six time-points from birth to 5…

Feldman, Ruth; Eidelman, Arthur I.

2009-01-01

340

Quantifying volatile organic compounds in porous media: effects of sampling method attributes, contaminant characteristics and environmental conditions.  

PubMed

Understanding how sampling methods can impact the accuracy of volatile organic compound (VOC) measurements in samples of soil and subsurface porous media is often critical to sound decision making during characterization and remediation of VOC contaminated sites. In this study, the accuracy of VOC measurements was investigated using an experimental apparatus packed with sandy porous media and contaminated with known levels of VOCs, which could be sampled using different methods under variable, but controlled, conditions. Five sampling methods were examined representing different degrees of porous media disaggregation and duration of atmospheric exposure (MDE) that can occur during sample acquisition and preservation in the field. Three pervasive VOCs were studied (1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene) at low and high concentration levels. Five porous media temperatures were examined ranging from 5 to 80 degrees C to represent ambient or thermal remediation conditions and two water saturation levels were used to mimic vadose zone and groundwater zone conditions. The results of this research demonstrated that sampling method attributes can impact the accuracy of VOC measurements in porous media by causing negative bias in VOC concentration data ranging from near 0 to 90% or more. The magnitude of the negative bias is dependent on the attributes of the sampling method used (i.e., level of MDE) and interactions with key contaminant properties and environmental conditions (i.e., VOC KH, porous media temperature, water saturation level). PMID:19475967

Oesterreich, Ryan C; Siegrist, Robert L

2009-04-15

341

Validation and adjustment of the mathematical prediction model for human sweat rate responses to outdoor environmental conditions.  

PubMed

Under outdoor conditions this model was over estimating sweat loss response in shaded (low solar radiation) environments, and underestimating the response when solar radiation was high (open field areas). The present study was conducted in order to adjust the model to be applicable under outdoor environmental conditions. Four groups of fit acclimated subjects participated in the study. They were exposed to three climatic conditions (30 degrees, 65% rh; 31 degrees C, 40% rh; and 40 degrees C, 20% rh) and three levels of metabolic rate (100, 300 and 450 W) in shaded and sunny areas while wearing shorts, cotton fatigues (BDUs) or protective garments. The original predictive equation for sweat loss was adjusted for the outdoor conditions by evaluating separately the radiative heat exchange, short-wave absorption in the body and long-wave emission from the body to the atmosphere and integrating them in the required evaporation component (Ereq) of the model, as follows: Hr = 1.5SL0.6/I(T) (watt) H1 = 0.047Me.th/I(T) (watt), where SL is solar radiation (W.m-2), Me.th is the Stephan Boltzman constant, and I(T) is the effective clothing insulation coefficient. This adjustment revealed a high correlation between the measured and expected values of sweat loss (r = 0.99, p < 0.0001). PMID:7737107

Shapiro, Y; Moran, D; Epstein, Y; Stroschein, L; Pandolf, K B

1995-05-01

342

Transcriptional Response of Desulfovibrio vulgaris Hildenborough to Oxidative Stress Mimicking Environmental Conditions  

SciTech Connect

Sulphate-reducing bacteria are anaerobes readily found in oxic-anoxic interfaces. Multiple defence pathways against oxidative conditions were identified in these organisms and proposed to be differentially expressed under different concentrations of oxygen, contributing to their ability to survive oxic conditions. In this study, Desulfovibrio vulgaris Hildenborough cells were exposed to the highest concentration of oxygen that sulphate-reducing bacteria are likely to encounter in natural habitats, and the global transcriptomic response was determined. 307 genes were responsive, with cellular roles in energy metabolism, protein fate, cell envelope and regulatory functions, including multiple genes encoding heat shock proteins, peptidases and proteins with heat shock promoters. Of the oxygen reducing mechanisms of D. vulgaris only the periplasmic hydrogen-dependent mechanism is up-regulated, involving the [NiFeSe]hydrogenase, formate dehydrogenase(s) and the Hmc membrane complex. The oxidative defence response concentrates on damage repair by metal-free enzymes. These data, together with the down regulation of the Fur operon, which restricts the availability of iron, and the lack of response of the PerR operon, suggest that a major effect of this oxygen stress is the inactivation and/or degradation of multiple metalloproteins present in D. vulgaris as a consequence of oxidative damage to their metal clusters.

Pereira, Patricia M.; He, Qiang; Xavier, Antonio V.; Zhou, Jizhong; Pereira, Ines A.C.; Louro, Ricardo O.

2008-03-12

343

Effects of wearing compression garments on thermoregulation during simulated team sport activity in temperate environmental conditions.  

PubMed

Anecdotal evidence suggests compression garments (CGs) are being worn underneath normal playing attire during team sports. Wearing CGs as a baselayer could possibly increase heat storage, and so this field study investigated the effects of wearing CGs, comprising knee-length shorts and short-sleeved top underneath normal match-day attire (COMP), versus normal match-day attire alone (NORM) on thermoregulation during simulated team sport activity. Ten match-fit field hockey players twice performed 4x15min exercise bouts consisting of repeated cycles of intermittent, varied-intensity 20m shuttle running (Loughborough intermittent shuttle test), once in COMP and once in NORM. Testing was conducted in an indoor gymnasium (ambient conditions: approximately 17 degrees C, approximately 60% relative humidity). Participants acted as their own controls. Heart rate (HR), 15m sprint time, ratings of perceived exertion (RPE), blood lactate concentration, sweat rate and body core temperature (T(core)) were similar between trials (p>0.05). Mean skin temperature (T(skin)) was significantly higher in COMP than NORM (p<0.05). Overall, CGs worn as a baselayer during simulated team sport exercise in temperate ambient conditions had no thermoregulatory benefits nor any detrimental effects on T(core), physiological performance or dehydration. However, the higher T(skin) may affect individual preference for wearing CGs as an undergarment during team sports. PMID:18078787

Houghton, Laurence A; Dawson, Brian; Maloney, Shane K

2007-12-19

344

Impact of environmental conditions on the marine natural product bryostatin 1.  

PubMed

Marine Natural Products (MNPs), such as bryostatin 1, are exposed to a range of physical and chemical conditions through the life cycle of the host organism. These include exposure to sunlight, oxidizing and reducing agents, cation binding, and adsorption to reactive metal oxide surfaces. Using Fourier Transform-Ion Cyclotron Resonance (FT-ICR), Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS), UV/Vis absorbance spectroscopy, and molecular modeling, we studied the impact of UV light, TiO2, I2, and reaction with FeCl3 on the structure of bryostatin 1. Our results demonstrate that natural conditions transform bryostatin to a number of structures, including one with a molar mass of 806 Da, which we have previously identified in the sediment collected from the Gulf of Mexico. To date, at least 20 different structures of bryostatin have been reported in the literature. This work suggests that these variations may be products of the chemical environment in which the bryozoa Bugula neritina resides and are not the result of genetic variations within Bugula. PMID:16835096

Manning, Thomas J; Rhodes, Emily; Land, Michael; Parkman, Render; Sumner, Brandy; Lam, Tukiet T; Marshall, Alan G; Phillips, Dennis

2006-05-20

345

The effect of technetium-99 and environmental conditions on soybean physiology  

SciTech Connect

Technetium-99 is considered a long-term risk of nuclear energy because it has a long half-life, mass 99 is produced at a high yield during nuclear fission, and Tc-99 is taken up readily by aquatic and terrestrial organisms. Plants are an important intermediate of Tc-99 food chain transfer to animals and humans. The present study investigated adenosine triphosphate (ATP), photosynthesis and structural responses of intact soybean seedlings [Glycine max (L.) Merr. cv. Williams] to micromolar amounts of Tc-99 under different ambient light levels. Adenosine triphosphate was measured directly in primary leaf extract after 6 d of exposure to Tc at varying concentrations (up to 5 {mu}M Tc-99). The results indicated that under full light conditions (320 {mu}mol photon m{sup {minus}2}s{sup {minus}1}), soy bean primary leaves contained nanomolar concentrations of ATP almost twice as high as for untreated plants. With a reduction of light intensity by 50%, primary leaf pertechnetate uptake and leaf ATP content were reduced regardless of Tc-99 exposure levels. Gas exchange measurements with a Li-Cor 6200 Portable Photosynthesis system indicated a significant decline of photosynthetic rate and a higher internal CO{sub 2} accumulation under full light conditions, while stomatal conductance decreased as a function of Tc-99 concentration. Several possible mechanisms of Tc interaction with chloroplast ultrastructure are proposed. A hypothesis related to the metabolic behavior of Tc in higher plants is presented. 34 refs., 6 figs.

Degenkolb, S.J.; Neel, J.W.; Papin, P.J. [Scripps Clinic and Research Foundation, La Jolla, CA (United States)

1994-11-01

346

Chronic unpredictable stress augments +3,4-methylenedioxymethamphetamine-induced monoamine depletions: the role of corticosterone.  

PubMed

Exposure to stress alters the behavioral and neurochemical effects of drugs of abuse. However, it is unknown if chronic stress can affect the serotonergic depletions induced by the psychostimulant drug 3,4-methylenedioxymethamphetamine (MDMA). Rats were exposed to 10 days of chronic unpredictable stress (CUS) which resulted in the predicted elevation of basal plasma corticosterone concentrations. On the 11th day, rats received four challenge doses of MDMA (5 mg/kg every 2 h, i.p.) or saline. Five days later, rats were killed and serotonin (5-HT) and dopamine content were measured in the striatum, hippocampus, and frontal cortex. MDMA produced greater depletions of 5-HT in all three brain regions of rats pre-exposed to CUS compared to rats not exposed to CUS. CUS-exposed rats also had an augmented acute hyperthermic response but a similar increase in plasma corticosterone after challenge injections of MDMA compared with non-stressed rats similarly challenged with MDMA. Moreover, CUS-exposed rats exhibited an MDMA-induced depletion of striatal dopamine that was absent in non-stressed rats that received MDMA. To investigate the role of corticosterone in these effects, the corticosterone synthesis inhibitor, metyrapone (50 mg/kg i.p.), was administered prior to each stressor on each of the 10 days of CUS. Metyrapone blocked the chronic stress-induced elevation in basal plasma corticosterone, prevented the enhancement of MDMA-induced hyperthermia, and blocked the enhanced depletions of 5-HT and dopamine in CUS-exposed rats, but had no effect on the acute MDMA-induced increases in plasma corticosterone. These findings suggest that CUS alone can increase the basal level of corticosterone that in turn, plays an important role in enhancing the sensitivity of both 5-HT and dopamine terminals to the hyperthermic and monoamine depleting effects of MDMA without altering the acute corticosterone response to an MDMA challenge. PMID:19409219

Johnson, B N; Yamamoto, B K

2009-02-03

347

Strain differences in sucrose preference and in the consequences of unpredictable chronic mild stress.  

PubMed

Effects of unpredictable chronic mild stress (UCMS) on anhedonic-like behaviour, physical state, body weight, learning and memory were investigated in three strains of mice. These strains were chosen among 11 strains that were tested in a first experiment for their sucrose consumption and preference for sucrose solutions of different concentrations. In the second experiment, groups of mice of the CBA/H, C57BL/6 and DBA/2 strains were submitted to 7 weeks of UCMS. Measures of the sucrose consumption, the evaluation of the physical state and the measurement of body weight were weekly assessed. Following 4-week period of UCMS, sub-groups of stressed and non-stressed mice were submitted to the spontaneous alternation test in the Y-maze, and then to the water-maze test for spatial learning and memory. UCMS induced a significant decrease of the sucrose consumption in CBA/H and in C57BL/6 but not in DBA/2 mice. The UCMS effect on sucrose intake in CBA/H mice was associated with a body weight loss and a physical state degradation. Spatial learning in a water maze was not disturbed by UCMS, however, a long-term memory impairment was observed in CBA/H stressed mice during a probe test. In the Y-maze, UCMS did not modify spontaneous alternation. These results show both an anhedonic-like and an amnesic effect of UCMS in CBA/H mice. They also reveal a difference of sensitivity to UCMS according to the strain of mice. PMID:15325787

Pothion, Stéphanie; Bizot, Jean-Charles; Trovero, Fabrice; Belzung, Catherine

2004-11-01

348

Deficiency in Endocannabinoid Signaling in the Nucleus Accumbens Induced by Chronic Unpredictable Stress  

PubMed Central

The nucleus accumbens (NAc) is a critical component of the reward circuitry, and dysfunction of the NAc may account for anhedonia and other symptoms of depression. Here, we investigated whether alterations in endocannabinoid (eCB) signaling in the NAc contribute to depression-like behaviors induced by chronic unpredictable stress (CUS) in mice. We compared three types of eCB/CB1 receptor-mediated synaptic plasticity in slices prepared from the NAc core of control and stress-exposed mice: depolarization-induced suppression of excitation, long-term depression, and the depression of field excitatory postsynaptic potentials (fEPSPs) induced by group I metabotropic glutamate receptor agonist DHPG. CUS (5–6-week exposure to stressors), but not sub-CUS (1 week exposure to stressors), induces depression-like behaviors and impairs these forms of eCB/CB1 receptor-mediated plasticity examined in the NAc core. Neither sub-CUS nor CUS altered the tissue contents of the eCBs, anandamide and 2-arachidonoylglycerol in the striatum. However, exposure to CUS, but not to sub-CUS, attenuated the depression of fEPSPs induced by the CB1 receptor agonist WIN 55?212-2. CUS exposure reduced the maximal effect without affecting the EC50 of WIN 55?212-2 to induce fEPSP depression. Thus, impaired CB1 receptor function could account for CUS-induced deficiency in eCB signaling in the NAc. Both CUS-induced deficiency in eCB signaling and depression-like behaviors were reversed by in vivo administration of antidepressant fluoxetine. These results suggest that downregulation of eCB signaling in the NAc occurs after CUS and contributes to the pathophysiology of depression.

Wang, Wei; Sun, Dalong; Pan, Bin; Roberts, Christopher J; Sun, Xinglai; Hillard, Cecilia J; Liu, Qing-song

2010-01-01

349

Paraheliotropism in Robinia pseudoacacia L.: an efficient strategy to optimise photosynthetic performance under natural environmental conditions.  

PubMed

We assessed the contribution of leaf movements to PSII photoprotection against high light and temperature in Robinia pseudoacacia. Gas exchange and chlorophyll a fluorescence measurements were performed during the day at 10:00, 12:00, 15:00 and 18:00 hours on leaves where paraheliotropic movements were restrained (restrained leaves, RL) and on control unrestrained leaves (UL). RL showed a strong decrease of net photosynthesis (A(n)), stomatal conductance (g(sH2O)), quantum yield of electron transport (PhiPSII), percentage of photosynthesis inhibited by O2 (IPO) and photochemical quenching (q(P)) in the course of the day, whereas, a significant increase in C(i)/C(a) and NPQ was observed. Contrary to RL, UL had higher photosynthetic performance that was maintained at elevated levels throughout the day. In the late afternoon, A(n), g(sH2O), PhiPSII and q(P) of RL showed a tendency to recovery, as compared to 15:00 hours, even if the values remained lower than those measured at 10:00 hours and in UL. In addition, contrary to UL, no recovery was found in F(v)/F(m) at the end of the study period in RL. Data presented suggest that in R. pseudoacacia, leaf movements, by reducing light interception, represent an efficient, fast and reversible strategy to overcome environmental stresses such as high light and temperature. Moreover, paraheliotropism was able to protect photosystems, avoiding photoinhibitory damage, leading to a carbon gain for the plant. PMID:18304193

Arena, C; Vitale, L; De Santo, A Virzo

2008-03-01

350

Effects of cool and hot humid environmental conditions on neuroendocrine responses of horses to treadmill exercise.  

PubMed

To determine the effects of exercise, high heat and humidity and acclimation on plasma adrenaline, noradrenaline, beta-endorphin and cortisol concentrations, five horses performed a competition exercise test (CET; designed to simulate the speed and endurance test of a three-day event) in cool dry (CD) (20 degrees C/40% RH) and hot humid (30 degrees C/80% RH) conditions before (pre-acclimation) and after (post-acclimation) a 15 day period of humid heat acclimation. Plasma adrenaline and noradrenaline concentrations pre-acclimation were significantly increased compared with exercise in the CD trial at the end of Phases C (P<0.05) and D (P<0.05 and P<0.01, respectively) and at 2 min recovery (P<0.01), with adrenaline concentrations still elevated after 5 min of recovery (P<0.001). Plasma beta-endorphin concentrations were increased at the end of Phases C (P<0.05) and X (P<0.01) and at 5 and 30 min recovery (P<0.05) in the pre-acclimation session. Plasma cortisol concentrations were elevated after the initial warm up period pre-acclimation (P<0.01) and at the end of Phase C (P<0.05), compared with the CD trial. A 15 day period of acclimation significantly increased plasma adrenaline concentrations at 2 min recovery (P<0.001) and plasma cortisol concentration at the end of Phase B (P<0.01) compared with pre-acclimation. Acclimation did not significantly influence noradrenaline or beta-endorphin responses to exercise, although there was a trend for plasma beta-endorphin to be lower at the end of Phases C and X and after 30 min recovery compared with pre-acclimation. Plasma adrenaline, noradrenaline, beta-endorphin and cortisol concentrations were increased by exercise in cool dry conditions and were further increased by the same exercise in hot humid conditions. Exercise responses post-acclimation suggest that adrenaline and noradrenaline may play a role in the adaptation of horses to thermal stress and that changes in plasma beta-endorphin concentrations could be used as a sensitive indicator of thermal tolerance before and after acclimation. The use of plasma cortisol as a specific indicator of heat stress and thermal tolerance before or after acclimation in exercising horses appears limited. PMID:12359485

Williams, R J; Marlin, D J; Smith, N; Harris, R C; Haresign, W; Davies Morel, M C

2002-07-01

351

Peroxisomal Monodehydroascorbate Reductase. Genomic Clone Characterization and Functional Analysis under Environmental Stress Conditions1  

PubMed Central

In plant cells, ascorbate is a major antioxidant that is involved in the ascorbate-glutathione cycle. Monodehydroascorbate reductase (MDAR) is the enzymatic component of this cycle involved in the regeneration of reduced ascorbate. The identification of the intron-exon organization and the promoter region of the pea (Pisum sativum) MDAR 1 gene was achieved in pea leaves using the method of walking polymerase chain reaction on genomic DNA. The nuclear gene of MDAR 1 comprises nine exons and eight introns, giving a total length of 3,770 bp. The sequence of 544 bp upstream of the initiation codon, which contains the promoter and 5? untranslated region, and 190 bp downstream of the stop codon were also determined. The presence of different regulatory motifs in the promoter region of the gene might indicate distinct responses to various conditions. The expression analysis in different plant organs by northern blots showed that fruits had the highest level of MDAR. Confocal laser scanning microscopy analysis of pea leaves transformed with Agrobacterium tumefaciens having the binary vectors pGD, which contain the autofluorescent proteins enhanced green fluorescent protein and enhanced yellow fluorescent protein with the full-length cDNA for MDAR 1 and catalase, indicated that the MDAR 1 encoded the peroxisomal isoform. The functional analysis of MDAR by activity and protein expression was studied in pea plants grown under eight stress conditions, including continuous light, high light intensity, continuous dark, mechanical wounding, low and high temperature, cadmium, and the herbicide 2,4-dichlorophenoxyacetic acid. This functional analysis is representative of all the MDAR isoforms present in the different cell compartments. Results obtained showed a significant induction by high light intensity and cadmium. On the other hand, expression studies, performed by semiquantitative reverse transcription-polymerase chain reaction demonstrated differential expression patterns of peroxisomal MDAR 1 transcripts in pea plants grown under the mentioned stress conditions. These findings show that the peroxisomal MDAR 1 has a differential regulation that could be indicative of its specific function in peroxisomes. All these biochemical and molecular data represent a significant step to understand the specific physiological role of each MDAR isoenzyme and its participation in the antioxidant mechanisms of plant cells.

Leterrier, Marina; Corpas, Francisco J.; Barroso, Juan B.; Sandalio, Luisa M.; del Rio, Luis A.

2005-01-01

352

Comparative scuffing performance and chemical analysis of metallic surfaces for air-conditioning compressors in the presence of environmentally friendly CO 2 refrigerant  

Microsoft Academic Search

Carbon dioxide (CO2) has received significant interest as an alternative refrigerant for air-conditioning compressors due to its environmental benefits. These environmental benefits include zero ozone depletion potential and minimal global warming potential compared to commonly used hydrochlorofluorocarbon and hydrofluorocarbon refrigerants. This study presents results for three typical metallic tribopairs commonly found in air conditioning compressors, namely, Al390-T6, gray cast iron,

Emerson Escobar Nunez; Nicholaos G. Demas; Kyriaki Polychronopoulou; Andreas A. Polycarpou

2010-01-01

353

[Developmental periods and adaptation of parthenites of Eurytrema pancreaticum (Dicrocoeliidae, Trematoda) to environmental conditions].  

PubMed

Data are given on the developmental periods of parthenites of E. pancreaticum (Janson, 1889) from the Far East of the USSR. The growth and formation of parthenites were found to take place from May to October and to coincide with the active period of the intermediate host's life cycle. With the decrease of autumn temperatures to 8 degrees the growth of parthenites slows down and ceases completely in October. The pause in the development of parthenites from October to April causes longer developmental periods of parthenites as compared to those in the regions of tropical and subtropical climate. Under laboratory conditions at a temperature of 8 to 22 degrees the development of parthenites proceeds without any intervals within 6.5 months. PMID:1018937

Dvoriadkin, V A

354

Aquatic environmental conditions in Chickamauga Reservoir during operation of Sequoyah Nuclear Plant: Fourth annual report, 1984  

SciTech Connect

The Tennessee Valley Authority has conducted water quality and biological monitoring in Chickamauga Reservoir from 1980 through 1984 as required by the National Pollutant Discharge Elimination System Permit for Sequoyah Nuclear Plant (SQN). Evaluation of 1984 operational monitoring data, comparison of these data to previous operational and preoperational data, and recommendations for continuation or discontinuation of each type of study are presented in this report. Plant operations, which were limited during the initial period of operational monitoring (1980 and 1981) because of plant testing, increased in 1982 and probably reflected ''normal'' conditions in 1983 and 1984. Comparisons of aquatic parameters upstream and downstream of SQN showed numerous differences among stations and/or over time. Most of these differences were considered unimportant or thought to be associated with factors other than SQN. Therefore, it is recommended that the following be discontinued: benthic macroinvertebrate community studies; mollusk bioaccumulation studies; fish impingement studies; fish gill net studies; and fish creel studies. Plankton studies should continue.

Bruggink, D.J.; Buchanan, J.P.; Dycus, D.L.; Murray, S.A.; Ostrowski, P. Jr.; Smith, A.O.; Swor, C.T.; Tomljanovich, D.A.; Wade, D.C.; Webb, D.H.

1985-06-01

355

Monitoring of the environmental conditions inside the dome of the 4m Blanco Telescope at CTIO  

NASA Astrophysics Data System (ADS)

Between February and April 2009 a number of ultrasonic anemometers, temperature probes and dust sensors were operated inside the CTIO Blanco telescope dome. These sensors were distributed in a way that temperature and 3 dimensional wind speeds were monitored along the line of sight of the telescope. During telescope operations, occasional seeing measurements were obtained using the Mosaic CCD imager and the CTIO site monitoring MASS-DIMM system. In addition, also a Lunar Scintillometer (LuSci) was operated over the course of a few nights inside the dome. We describe the instrumental setup and first preliminary results on the linkage of the atmospheric conditions inside the dome to the overall image quality.

Els, S. G.; Abbott, T. M. C.; Bustos, E. B.; Seguel, J.; Walker, D. E.; Berdja, A.; Riddle, R.; Schöck, M.; Skidmore, W.; Travouillon, T.

2010-07-01

356

Phytoplankton summer bloom dynamics in the Bahía Blanca Estuary in relation to changing environmental conditions  

NASA Astrophysics Data System (ADS)

We examined austral summer phytoplankton data (December-March) that cover the years 1978-2008 and compared with physico-chemical and meteorological variations in the Bahía Blanca Estuary, Argentina. During the years 1978-1982, 1992-1993 and 2006-2008, counts of phytoplankton abundance showed an increase in recent summers; from a mean value of 12×103 cells L-1 in 1978 to 2239×103 cells L-1 in 2008, while the chlorophyll concentration remained relatively constant (8.5±2.5 ?g L-1, CV=27%) over the continuous time series (1978-2008). The rise in the ratio ‘cell abundance: chlorophyll concentration’ was linked to modifications in species composition, from dominance of phytoflagellates (10-20 ?m) and relatively large diatoms (e.g., Cyclotella striata 25-38 ?m, Paralia sulcata 15-70 ?m, Cerataulina pelagica 18-30 ?m, Thalassiosra hendeyi 27-52 ?m) towards the dominance of the small (5-15 ?m) centric diatom Thalassiosira minima, which reached >80% of the total phytoplankton abundance in summers 2006-2008. The Bahía Blanca Estuary has undergone climate modifications and increasing anthropogenic disturbances during the last three decades. In the early 1990s, regional climatic conditions revealed a significant shift. Additionally, dredging activities were initiated to allow the traffic of large ships, rising the levels of suspended sediments, and the invasive copepod Eurytemora americana was introduced via ballast waters into the estuary and has displaced the dominance of the native copepod Acartia tonsa towards summer periods. The examination of physico-chemical conditions of the estuary showed a trend to increase in the minima of water temperature and higher water turbidity, dissolved phosphate, nitrite and nitrate concentrations in the pelagic environment in recent summers. We discuss the potential effects of these changes and trophic interactions on the structure and composition of the phytoplankton summer blooms in this temperate and eutrophic estuary in the Southwestern Atlantic.

Guinder, Valeria A.; Popovich, Cecilia A.; Molinero, Juan Carlos; Marcovecchio, Jorge

2013-01-01

357

Crassulacean Acid Metabolism in the Succulent C4 Dicot, Portulaca oleracea L Under Natural Environmental Conditions 1  

PubMed Central

Crassulacean acid metabolism (CAM) was examined under natural environmental conditions in the succulent C4 dicot Portulaca oleracea L. Two groups of plants were monitored; one was watered daily (well watered), while the other received water once every 3 to 4 weeks to produce a ? of ?8 bars (drought stressed). Gas exchange, transpiration rate, and titratable acidity were measured for 24-hour periods during the growing season. CAM activity was greatest in drought-stressed plants during late August which had 13 hour days and day/night temperatures of 35/15°C. Under these conditions net CO2 uptake occurred slowly throughout the night. Diurnal fluctuations of titratable acidity took place in both leaves and stems with amplitudes of 17 and 47 microequivalents per gram fresh weight, respectively. Transpiration data indicated greater opening of stomata during the night than the day. CAM was less pronounced in drought-stressed P. oleracea plants in July and September; neither dark CO2 uptake nor positive carbon balance occurred during the July measurements. In contrast, well-watered plants appeared to rely on C4 photosynthesis throughout the season, although some acid fluctuations occurred in stems of these plants during September. To determine the fate of the CO2 assimilated at night in drought-stressed Portulaca plants, exposure to 14CO2 during the night followed by 9 hours of ambient air in the light. Malate was the predominant compound labeled during the night, with some citrate and aspartate. No 14CO2 release was detected during the following day and by midafternoon the majority of the label was found in the insoluble fraction (predominantly starch). These results substantiate our earlier work with growth-chamber-grown plants and show that limited CAM activity can occur in the succulent C4 dicot Portulaca oleracea L. under certain natural environmental conditions.

Koch, Karen E.; Kennedy, Robert A.

1982-01-01

358

Effects of environmental conditions on onset of xylem growth in Pinus sylvestris under drought  

PubMed Central

Summary We determined influence of environmental factors (air and soil temperature, precipitation, photoperiod) on onset of xylem growth in Scots pine (Pinus sylvestris L.) within a dry inner Alpine valley (750 m a.s.l., Tyrol, Austria) by repeatedly sampling micro-cores throughout 2007-2010 at two sites (xeric and dry-mesic) at the start of the growing season. Temperature sums were calculated in degree-days (DD) ? 5 °C from 1 January and 20 March, i.e. spring equinox, to account for photoperiodic control of release from winter dormancy. Threshold temperatures at which xylogenesis had a 0.5 probability of being active were calculated by logistic regression. Onset of xylem growth, which was not significantly different between the xeric and dry-mesic site, ranged from mid-April in 2007 to early May in 2008. Among most study years statistically significant differences (P < 0.05) in onset of xylem growth were detected. Mean air temperature sums calculated from 1 January until onset of xylem growth were 230 ± 44 DD (mean ± standard deviation) at the xeric and 205 ± 36 DD at the dry-mesic site. Temperature sums calculated from spring equinox until onset of xylem growth showed quite less variability during the four year study period amounting to 144 ± 10 and 137 ± 12 DD at the xeric and dry-mesic site, respectively. At both sites xylem growth was active when daily minimum, mean and maximum air temperatures were 5.3, 10.1 and 16.2 °C, respectively. Soil temperature thresholds and DD until onset of xylem growth differed significantly between sites indicating minor importance of root-zone temperature for onset of xylem growth. Although spring precipitation is known to limit radial growth in P. sylvestris exposed to dry inner Alpine climate, results of this study revealed that (i) a daily minimum air temperature threshold for onset of xylem growth in the range of 5-6 °C exists and (ii) air temperature sum rather than precipitation or soil temperature triggers start of xylem growth. Based on these findings we suggest that drought stress forces P. sylvestris to draw upon water reserves in the stem for enlargement of first tracheids after cambial resumption in spring.

Swidrak, Irene; Gruber, Andreas; Kofler, Werner; Oberhuber, Walter

2012-01-01

359

Fish assemblage structure and relations with environmental conditions in a Rocky Mountain watershed  

USGS Publications Warehouse

Fish and habitat were sampled from 110 reaches in the Salt River basin (Idaho and Wyoming) during 1996 and 1997 to assess patterns in fish assemblage structure across a Rocky Mountain watershed. We identified four distinct fish assemblages using cluster analysis: (1) allopatric cutthroat trout (Oncorhynchus clarki (Richardson, 1836)); (2) cutthroat trout - brook trout (Salvelinus fontinalis (Mitchell, 1814)) - Paiute sculpin (Cottus beldingi Eigenmann and Eigenmann, 1891); (3) cutthroat trout - brown trout (Salmo trutta L., 1758) - mottled sculpin (Cottus bairdi Girard, 1850); and (4) Cyprinidae-Catostomidae. The distribution of fish assemblages was explained by thermal characteristics, stream geomorphology, and local habitat features. Reaches with allopatric cutthroat trout and the cutthroat trout - brook trout - Paiute sculpin assemblage were located in high-elevation, high-gradient streams. The other two fish assemblages were generally located in low-elevation streams. Associations between habitat gradients, locations of reaches in the watershed, and occurrence of species were further examined using canonical correspondence analysis. The results suggest that stream geomorphology, thermal conditions, and local habitat characteristics influence fish assemblage structure across a Rocky Mountain watershed, and they provide information on the ecology of individual species that can guide conservation activities. ?? 2004 NRC Canada.

Quist, M. C.; Hubert, W. A.; Isaak, D. J.

2004-01-01

360

Growth kinetics and energetics of a deep-sea hyperthermophilic methanogen under varying environmental conditions.  

PubMed

A hyperthermophilic deep-sea methanogen, Methanocaldococcus strain JH146, was isolated from 26°C hydrothermal fluid at Axial Volcano to model high temperature methanogenesis in the subseafloor. Emphasis was placed on defining growth kinetics, cell yields and growth energy demand (GE) across a range of conditions. The organism uses H2 and CO2 as its sole carbon and energy sources. At various temperatures, pHs, and chlorinities, its growth rates and cell yields co-varied while GE remained uniform at 1.69?×?10(-11) J cell(-1?)s(-1)?±?0.68?×?10(-11) J cell(-1?)s(-1) (s.d., n?=?23). An exception was at superoptimal growth temperatures where GE increased to 7.25?×?10(-11) J cell(-1?)s(-1) presumably due to heat shock. GE also increased from 5.1?×?10(-12) J cell(-1?)s(-1) to 7.61?×?10(-11) J cell(-1?)s(-1) as NH4 (+) concentrations decreased from 9.4?mM to 0.14?mM. JH146 did not fix N2 or assimilate NO3 (-), lacked the N2-fixing (cluster II) nifH gene, and became nitrogen limited below 0.14?mM NH4Cl. Nitrogen availability may impact growth in situ since ammonia concentrations at Axial Volcano are

Ver Eecke, Helene C; Akerman, Nancy H; Huber, Julie A; Butterfield, David A; Holden, James F

2013-05-06

361

Characteristics of a Microcystin-Degrading Bacterium under Alkaline Environmental Conditions  

PubMed Central

The pH of the water associated with toxic blooms of cyanobacteria is typically in the alkaline range; however, previously only microcystin-degrading bacteria growing in neutral pH conditions have been isolated. Therefore, we sought to isolate and characterize an alkali-tolerant microcystin-degrading bacterium from a water bloom using microcystin-LR. Analysis of the 16S rRNA gene sequence revealed that the isolated bacterium belonged to the genus Sphingopyxis, and the strain was named C-1. Sphingopyxis sp. C-1 can grow; at pH 11.0; however, the optimum pH for growth was pH 7.0. The microcystin degradation activity of the bacterium was the greatest between pH 6.52 and pH 8.45 but was also detected at pH 10.0. The mlrA homolog encoding the microcystin-degrading enzyme in the C-1 strain was conserved. We concluded that alkali-tolerant microcystin-degrading bacterium played a key role in triggering the rapid degradation of microcystin, leading to the disappearance of toxic water blooms in aquatic environments.

Okano, Kunihiro; Shimizu, Kazuya; Kawauchi, Yukio; Maseda, Hideaki; Utsumi, Motoo; Zhang, Zhenya; Neilan, Brett A.; Sugiura, Norio

2009-01-01

362

Temporal dynamics of circulating persistent organic pollutants in a fasting seabird under different environmental conditions.  

PubMed

Temporal dynamics of persistent organic pollutants (POPs) were examined in fasting common eider (Somateria mollissima) females in one subarctic (68° N; over 5 years) and one high arctic colony (78° N; 3 years). Blood concentrations of polychlorinated biphenyl (PCB)-153; 1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE), and hexachlorobenzene (HCB) were measured twice each season in eider females (total n = 162) during incubation (at day 5 and day 20). The mean wet weight concentrations of PCB-153 were ~3-5 times higher in the subarctic colony, whereas p,p'-DDE and HCB concentrations tended to be higher in high arctic than in subarctic eiders late in the incubation period. All POPs increased during incubation fast, but the relative increase in mean concentration varied more among years in high arctic than in subarctic eiders. In the high arctic, both lipid-metabolism and the increase in circulating POP concentrations were highest in the year when the mean ambient temperature was lowest. Moreover, females with low body condition and high lipid metabolism (body mass loss) had stronger increase in circulating concentrations of p,p'-DDE and HCB; the effect size being within the same order of magnitude in the two colonies. Hence, since eiders at high latitudes metabolized relatively more lipids, they experienced higher exposure of p,p'-DDE and HCB over the incubation period than birds inhabiting the more benign subarctic region. PMID:22938172

Bustnes, Jan Ove; Moe, Børge; Hanssen, Sveinn Are; Herzke, Dorte; Fenstad, Anette A; Nordstad, Tore; Borgå, Katrine; Gabrielsen, Geir W

2012-08-31

363

The impact of exceptionally warm summer inflow events on the environmental conditions in the Bornholm Basin  

NASA Astrophysics Data System (ADS)

In late summer 2002 and 2003, exceptionally warm inflow events of saline water were observed in the Baltic. These warm saline waters were embedded in the halocline of the Bornholm Basin and caused a strong anomaly of the seasonal temperature cycle. The temperature in October 2002 was the highest ever observed in the halocline of the Bornholm Basin. Although the oxygen content of the inflowing water was only about 1.5 ml l- 1 at the Darss Sill, it caused a moderate ventilation of the halocline in the Bornholm Basin. On the way through the Arkona Basin, the entrainment of ambient water increased the oxygen content of the inflowing saline water masses. Warm summer inflows were rare events in the last 50 years, but their frequency has increased since 1990. This is likely caused by climate change. The analysis of a 50-year time series of hydrographic parameters reveals significant changes of the thermal regime around the year 1988. The winter surface and intermediate water temperatures of the Bornholm Basin increased by about 1 °C. Also, the duration of warm water in the surface layer was prolonged after 1988. A high correlation between the minimum intermediate winter water temperatures and the NAO winter index was found. Since temperature is a key parameter for many biological processes various responses of the ecosystem to the change in hydrographic conditions could be expected. Possible biological implications of the warm inflow events for the ecosystem are discussed.

Mohrholz, Volker; Dutz, Jörg; Kraus, Gerd

2006-05-01

364

Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions  

NASA Astrophysics Data System (ADS)

A mathematical model for predicting human thermal and regulatory responses in cold, cool, neutral, warm, and hot environments has been developed and validated. The multi-segmental passive system, which models the dynamic heat transport within the body and the heat exchange between body parts and the environment, is discussed elsewhere. This paper is concerned with the development of the active system, which simulates the regulatory responses of shivering, sweating, and peripheral vasomotion of unacclimatised subjects. Following a comprehensive literature review, 26 independent experiments were selected that were designed to provoke each of these responses in different circumstances. Regression analysis revealed that skin and head core temperature affect regulatory responses in a non-linear fashion. A further signal, i.e. the rate of change of the mean skin temperature weighted by the skin temperature error signal, was identified as governing the dynamics of thermoregulatory processes in the cold. Verification and validation work was carried out using experimental data obtained from 90 exposures covering a range of steady and transient ambient temperatures between 5°C and 50°C and exercise intensities between 46 W/m2 and 600 W/m2. Good general agreement with measured data was obtained for regulatory responses, internal temperatures, and the mean and local skin temperatures of unacclimatised humans for the whole spectrum of climatic conditions and for different activity levels.

Fiala, D.; Lomas, K. J.; Stohrer, M.

365

Characteristics of a Microcystin-Degrading Bacterium under Alkaline Environmental Conditions.  

PubMed

The pH of the water associated with toxic blooms of cyanobacteria is typically in the alkaline range; however, previously only microcystin-degrading bacteria growing in neutral pH conditions have been isolated. Therefore, we sought to isolate and characterize an alkali-tolerant microcystin-degrading bacterium from a water bloom using microcystin-LR. Analysis of the 16S rRNA gene sequence revealed that the isolated bacterium belonged to the genus Sphingopyxis, and the strain was named C-1. Sphingopyxis sp. C-1 can grow; at pH 11.0; however, the optimum pH for growth was pH 7.0. The microcystin degradation activity of the bacterium was the greatest between pH 6.52 and pH 8.45 but was also detected at pH 10.0. The mlrA homolog encoding the microcystin-degrading enzyme in the C-1 strain was conserved. We concluded that alkali-tolerant microcystin-degrading bacterium played a key role in triggering the rapid degradation of microcystin, leading to the disappearance of toxic water blooms in aquatic environments. PMID:20224628

Okano, Kunihiro; Shimizu, Kazuya; Kawauchi, Yukio; Maseda, Hideaki; Utsumi, Motoo; Zhang, Zhenya; Neilan, Brett A; Sugiura, Norio

2010-02-22

366

Study on corrosion behaviors of sintered Nd-Fe-B magnets in different environmental conditions  

SciTech Connect

Nd-Fe-B magnets have outstanding magnetic properties, but their corrosion resistance is poor because the rare-earth-rich phases in them are easily oxidized. In this article, we report an investigation of the corrosion behaviors of sintered Nd-Fe-B magnets with varied compositions in different corrosion conditions. The weight losses of the magnets after corrosion testing were measured after brushing off the corrosion products. The magnetic flux losses of the magnets were measured using a fluxmeter. A scanning electron microscope equipped with an energy dispersive x-ray analysis system was employed to observe the corrosion morphology. It was found that the humid-heat resistance of the magnets was obviously improved by partially substituting Dy for Nd and adding minor Co. The corrosion products and morphologies of Nd-Fe-B magnets for the autoclave test were different from those for the constant humid-heat test. The corrosion rates of the magnets for the former were much slower than for the latter; this is probably because the high-pressure steam led to an oxygen-deficient atmosphere, and the liquid film on the surface of the magnet specimens hindered the diffusion of oxygen into the bulk for the autoclave test.

Li, J. J.; Li, A. H.; Zhu, M. G.; Pan, W.; Li, W.

2011-04-01

367

Influence of construction on hydrogeological and environmental conditions in the karst region, eastern Herzegovina, Yugoslavia  

NASA Astrophysics Data System (ADS)

The region of eastern Herzegovina and Dubrovnik coastal belt is one of the hydrogeologically and hydrologically most interesting regions of Yugoslavia karst. The main water course in the region is the Trebišnjica river, the largest sinking river in Europe. All the poljes in the catchment area are temporary flooded, hydrologically separated, and closed karst entities. Enormous quantities of available water are not evenly disturbed neither in the time nor in the space. The Trebišnjica Hydrosystem project uses the basic concept of total water regime organization and its multipurpose utilization. With the construction of seven dams, six artificial reservoirs, six tunnels (with total length, 57 km), and four canals (with total length 74 km) the natural regime of surface and underground waters has been completely changed. As a consequence of water regime disturbance, a lot of changes have been observed in the catchment area: changes in the karst aquifers; local changes of climate conditions; eolic erosion effect; influence on the karst underground and littoral belt; influence on the springs yield; influence on adjacent catchment area; pollution of karst aquifers and influence of storage reservoirs on seismicity—induced seismicity. This article presents influences observed after the first stage of hydrosystem construction.

Milanovi?, Petar

1990-01-01

368

The influence of population dynamics and environmental conditions on salmon re-colonization after large-scale distrubance  

NASA Astrophysics Data System (ADS)

The transition from dispersal into unoccupied habitat to the establishment of a self-sustaining new population depends on the dynamics of the source and recipient populations, and the environmental conditions that facilitate or hinder exchange and successful reproduction. We used population growth rate, inter-annual variability estimates, habitat condition and size, hydrologic data, and an estimated dispersal effect to determine when colonizing pink salmon (Oncorhynchus gorbuscha) populations became self-sustaining after a long-term migration blockage (Hell’s Gate) was mitigated in the Fraser River, British Columbia, Canada. We used pink salmon spawning data from 1947 to 1987 in 66 streams to define populations, population growth rates, and the level of dispersal to newly accessible habitats. We also quantified the distance from source populations, the amount of newly accessible habitat, and determined whether stream flow conditions impeded fish passage at Hell’s Gate. Population dynamics models fit to observed data indicated that the combination of an initially large source population in the Fraser River below Hell’s Gate, high intrinsic growth rates linked to favorable climate-driven conditions, a constant supply of dispersers, and large amounts of newly available habitat resulted in the development of self-sustaining pink salmon populations in the Fraser River upstream of the historic barrier. Self-sustaining populations were developed within years of barrier removal and have continued to help expand the overall population of Fraser River pink salmon. However, not all locations had the same productivity and the magnitude of exchange among them was partly mediated by river conditions that permit or impede passage. Both re-colonized abundance levels were reduced and population spatial structure shifted relative to historic population abundance and spatial structure estimates.

Pess, G. R.; Hilborn, R.; Kloehn, K.; Quinn, T.

2010-12-01

369

Seasonal changes in condition and biochemical composition of the scallop Pecten maximus L. from suspended culture in the Ria de Arousa (Galicia, N.W. Spain) in relation to environmental conditions  

Microsoft Academic Search

Seasonal changes in condition and biochemical composition of striated adductor muscle, digestive gland and female gonad of raft cultured Pecten maximus L. in the Ria de Arousa (Galicia, N.W. Spain) were studied over 16 months in relation to environmental conditions and reproductive events. Pecten maximus in the Ria de Arousa showed a clear cycle of energy storage and utilisation. Between

A. J. Pazos; G. Román; C. P. Acosta; M. Abad; J. L. Sánchez

1997-01-01

370

Investigation of Techniques to Improve Continuous Air Monitors Under Conditions of High Dust Loading in Environmental Settings  

SciTech Connect

A number of DOE facilities, such as the Los Alamos National Laboratory (LANL) and the Waste Isolation Pilot Plant (WIPP), use alpha-particle environmental continuous air monitors (ECAMs) to monitor air for unwanted releases of radioactive aerosols containing such materials as plutonium and uranium. High sensitivity, ease of operation, and lack of false alarms are all important for ECAMs. The object of the project was to conduct investigations to improve operation of ECAMs, particularly under conditions where a lot of nonradioactive dust may be deposited on the filters (conditions of high dust loading). The presence of such dust may increase the frequency with which filters must be changed and can lead to an increased incidence of false alarms due to deteriorated energy resolution and response specificity to the radionuclides of interest. A major finding of the investigation, not previously documented, was that under many conditions thick layers of underlying nonradioactive dust do not decrease energy resolution and specificity for target radionuclides if the radioactive aerosol arrives as a sudden thin burst deposit, as commonly occurs in the early-warning alarm mode. As a result, operators of ECAMs may not need to change filters as often as previously thought and have data upon which to base more reliable operating procedures.

Suilou Huang; Stephen D. Schery; John C. Rodgers

2002-07-23

371

A standardized approach for estimating the permeability of plastic films to soil fumigants under various field and environmental conditions.  

PubMed

Minimizing atmospheric emissions of soil fumigants is critical for protecting human and environmental health. Covering the soil surface with a plastic tarp is a common approach to restrict fumigant emissions. The mass transfer of the fumigant vapors through the tarp is often the rate-limiting factor in fumigant emissions. An approach for standardizing measurements of film permeability is proposed that is based on determining the resistance (R) of films to diffusion of fumigants. Using this approach, values were determined for more than 200 film-chemical combinations under a range of temperature, relative humidity, and film handling conditions. Resistance to diffusion was specific for each fumigant/film combination, with the largest range of values observed for the fumigant chloropicrin. For each fumigant, decreased with increasing temperature. Changes in film permeability due to increases in temperature or field installation were generally less than a factor of five. For one film, values determined under conditions of very high relative humidity (approximately 100%) were at least 100 times lower than when humidity was very low (approximately 2%). This approach simplifies the selection of appropriate films for soil fumigation by providing rapid, reproducible, and precise measurements of their permeability to specific fumigants and application conditions. PMID:21869499

Papiernik, Sharon K; Yates, Scott R; Chellemi, Daniel O

372

Establishing Baseline environmental Conditions for the Proposed Yucca Mountain Repository, Nevada, U.S.A.  

SciTech Connect

Research is underway to develop baseline site conditions and design monitoring programs for assurance to offsite residents and for performance confirmation for the proposed Yucca Mountain (YM) high-level waste repository in Nevada. This includes evaluation of existing and potential impacts on the proposed ''land withdrawal'' for the repository. A significant portion of the proposed land withdrawal includes areas now managed as part of the Nevada Test Site (NTS), and there is both contamination and land disturbance associated with past NTS activities. Establishing baseline conditions for the land withdrawal is important to distinguish potential impacts from repository operations from those resulting from previous activities, including some that took place from activities outside the land withdrawal. Among existing contamination is mixed fission products associated with the Nuclear Rocket Testing Program on the NTS in the 1960s. Some of these sites are being remediated as part of a federal facility agreement between the U.S. Department of Energy and the State of Nevada. However, even where radionuclides exist at levels below regulatory concern, characterizing them may be desirable if they are above background. In addition, Forty Mile Wash, the major drainage on the east side of YM, may be transporting radionuclides created from Plowshare project nuclear cratering experiments on Buckboard Mesa on the NTS. Although contaminant levels are not anticipated to present a risk, the point at which Forty Mile Wash leaves the proposed land withdrawal would be the closest point for an offsite receptor to YM. In addition, there is existing land disturbance (not necessarily associated with contamination) on both the NTS, as well as the portions of the proposed land withdrawal currently managed by the U.S. Bureau of Land Management and the U.S. Air Force. To establish a land disturbance baseline, high resolution multispectral satellite imagery collected in 2004 as well as hyperspectral imagery is being analyzed. Spectral and textural classification algorithms are being used to separate disturbed features such as paths, jeep trails, and building structures from background features. Disturbance features will be incorporated into a geographic information system. Follow-on activities will include examining areas of disturbance on the ground to characterize them and determine their origin. A longer term issue is the potential for radionuclide transport in groundwater from past areas of underground nuclear testing on the NTS (particularly Pahute Mesa) to areas where releases from YM could occur. To better address this, groundwater advective pathways are being traced from the proposed repository environment toward upgradient areas on the NTS. The Death Valley Regional Flow System model (issued in 2004 by the U.S. Geological Survey), which incorporates both YM and the NTS, is being used as the framework for the modeling. It is further enhanced with information from the YM Site Scale model and YM- and NTS-defined hydrogeologic units. Simulated pathways that intersect nuclear testing areas will identify regions on the NTS where potentially contaminated groundwater may originate and the routes for its potential migration toward YM.

D.S. Shafer; K.F. Pohlmann; C.E. Russell; D. Hovey-Spencer; M. Ye

2004-12-21

373

Effect of calibration and environmental condition on the performance of direct-reading organic vapor monitors.  

PubMed

The performance of three MIRAN SapphIRe Portable Infrared Ambient Air Analyzers and three Century Portable Toxic Vapor Analyzers equipped with photoionization (PID) and flame ionization (FID) detectors was compared with charcoal tube sampling. Relationships were investigated using two different calibration methods at four cyclohexane concentrations, three temperatures, and four relative humidities. For the first method, the TVA monitors were calibrated with a single concentration of methane for the FID, and isobutylene for the PID. The SapphIRe monitors were zeroed and the monitor's manufacturer-supplied library was used. For the second method, a five-point cyclohexane calibration curve was created for each monitor. Comparison of the monitor results of each calibration method (pooled data) indicated a significant difference between methods (t-test, p < 0.001), The SapphIRe group had results closer to the charcoal tubes with the second calibration method, while the PID and FID monitor groups performed better using the first calibration method. The PID monitor group's performance was affected only at the 90% relative humidity (RH) condition. Using the first method, the monitor readings were compared with the charcoal tube average using mixed linear model analyses of variance (ANOVAs) and regression. The ANOVA results showed there was a statistically significant difference among readings from all monitor types (p <0.0001). The regression results demonstrated that the SapphIRe (r² = 0.97) and FID (r² = 0.92) monitor groups correlated well with the charcoal tubes. The PID monitor group had a similar correlation when 90% RH was excluded (r² = 0.94) but had a weaker correlation when it was included (r² = 0.58). The operator should take care when using these monitors at high concentrations and the PID monitors at high humidities, consider the variability between units of the same monitor, and conduct performance verification of the monitor being used. PMID:23016630

Coffey, Christopher; LeBouf, Ryan; Lee, Larry; Slaven, James; Martin, Stephen

2012-01-01

374

Photodegradation of selected herbicides in various natural waters and soils under environmental conditions.  

PubMed

The photochemical degradation of herbicides belonging to different chemical groups has been investigated in different types of natural waters (ground, river, lake, marine) and distilled water as well as in soils with different texture and composition. Studied herbicides and chemical groups included atrazine, propazine, and prometryne (s-triazines); propachlor and propanil (acetanilides); and molinate (thiocarbamate). The degradation kinetics were monitored under natural conditions of sunlight and temperature. Photodegradation experiments were performed in May through July 1998 at low concentrations in water samples (2-10 mg/L) and soil samples (5-20 mg/kg), which are close to usual field dosage. The photodegradation rates of all studied herbicides in different natural waters followed a pseudo-first order kinetics. The half-lives of the selected herbicides varied from 26 to 73 calendar days in waters and from 12 to 40 d in soil surfaces, showing that the degradation process depends on the constitution of the irradiated media. The presence of humic substances in the lake, river, and marine water samples reduces degradation rates in comparison with the distilled and ground water. On the contrary, the degradation in soil is accelerated as the percentage of organic matter increases. Generally, the photodegradation process in soil is faster than in water. The major photodegradation products identified by using gas chromatography-mass spectrometry (GC-MS) techniques were the hydroxy and dealkylated derivatives for s-triazines, the dechlorinated and hydroxy derivative for the anilides, and the keto-derivative for the thiocarbamate, indicating a similar mode of degradation for each chemical category. PMID:11215643

Konstantinou, I K; Zarkadis, A K; Albanis, T A

375

Impact of Environmental Conditions on the Form and Function of Candida albicans Biofilms.  

PubMed

Candida albicans, like other pathogens, can form complex biofilms on a variety of substrates. However, as the number of studies of gene regulation, architecture, and pathogenic traits of C. albicans biofilms has increased, so have differences in results. This suggests that depending upon the conditions employed, biofilms may vary widely, thus hampering attempts at a uniform description. Gene expression studies suggest that this may be the case. To explore this hypothesis further, we compared the architectures and traits of biofilms formed in RPMI 1640 and Spider media at 37°C in air. Biofilms formed by a/? cells in the two media differed to various degrees in cellular architecture, matrix deposition, penetrability by leukocytes, fluconazole susceptibility, and the facilitation of mating. Similar comparisons of a/a cells in the two media, however, were made difficult given that in air, although a/a cells form traditional biofilms in RPMI medium, they form polylayers composed primarily of yeast cells in Spider medium. These polylayers lack an upper hyphal/matrix region, are readily penetrated by leukocytes, are highly fluconazole susceptible, and do not facilitate mating. If, however, air is replaced with 20% CO2, a/a cells make a biofilm in Spider medium similar architecturally to that of a/? cells, which facilitates mating. A second, more cursory comparison is made between the disparate cellular architectures of a/a biofilms formed in air in RPMI and Lee's media. The results demonstrate that C. albicans forms very different types of biofilms depending upon the composition of the medium, level of CO2 in the atmosphere, and configuration of the MTL locus. PMID:23954841

Daniels, Karla J; Park, Yang-Nim; Srikantha, Thyagarajan; Pujol, Claude; Soll, David R

2013-08-16

376

Laboratory Test Methods to Determine the Degradation of Plastics in Marine Environmental Conditions  

PubMed Central

In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9?months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break?=??66% in 2?years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236?days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment.

Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

2012-01-01

377

Laboratory test methods to determine the degradation of plastics in marine environmental conditions.  

PubMed

In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9?months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break?=?-66% in 2?years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236?days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment. PMID:22737147

Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

2012-06-21

378

Impact of environmental conditions on the suitability of microconstituents as markers for determining nutrient loading from reclaimed water.  

PubMed

Nitrogen and phosphorous loading into waterways from designated beneficial uses of reclaimed water is a growing concern in many parts of the United States. Numerous studies have documented that organic microconstituents present in the reclaimed water can be utilized as indicators of its influence on surface water bodies. However, little to no information is available on the environmental attenuation of these microconstituents relative to the nutrients, which is a critical component in determining the effectiveness or limitations of those markers as a tool for elucidating their origins. In this study, the stability of selected markers (sucralose, carbamazepine, gadolinium anomaly, iohexol, and atenolol) was evaluated through bench-scale studies designed to simulate environmental conditions associated with biodegradation, adsorption, and photolysis. The primary pathway for nitrogen reduction was biodegradation (greater than 99%) while the highest phosphorous removal was due to adsorption (30-80%). Soils with low organic content were selected for this study. Sucralose was the most recalcitrant microconstituent in the environment with less than 15% removal by adsorption, biodegradation, or photolysis. Iohexol was too susceptible to photolysis (90% removal), and atenolol was susceptible to biodegradation (60-80% removal). Gd anomaly was fairly stable (less than 30% removal) in the environment. Carbamazepine was another efficacious marker for wastewater, but was susceptible (50% removal) to photolysis. Of the selected microconstituents, only atenolol showed any similarity with the attenuation observed for nitrate and none of the microconstituents showed any similarity with the attenuation observed for phosphorus. PMID:24054084

Badruzzaman, Mohammad; Oppenheimer, Joan A; Jacangelo, Joseph G

2013-08-21

379

Joint investigation of working conditions, environmental and system performance at recycling centres--development of instruments and their usage.  

PubMed

Recycling is a new and developing industry, which has only been researched to a limited extent. This article describes the development and use of instruments for data collection within a multidisciplinary research programme "Recycling centres in Sweden - working conditions, environmental and system performance". The overall purpose of the programme was to form a basis for improving the function of recycling centres with respect to these three perspectives and the disciplines of: ergonomics, safety, external environment, and production systems. A total of 10 instruments were developed for collecting data from employees, managers and visitors at recycling centres, including one instrument for observing visitors. Validation tests were performed in several steps. This, along with the quality of the collected data, and experience from the data collection, showed that the instruments and methodology used were valid and suitable for their purpose. PMID:19660737

Engkvist, I-L; Eklund, J; Krook, J; Björkman, M; Sundin, E; Svensson, R; Eklund, M

2009-08-05

380

Differential distribution of serotonin receptor subtypes in BNST(ALG) neurons: modulation by unpredictable shock stress.  

PubMed

The bed nucleus of the stria terminalis (BNST) plays a critical role in regulating the behavioral response to stress. Stressors that activate the BNST also activate serotonergic (5-HT) systems. Hence, maladaptive changes of 5-HT receptor expression may contribute to stress-induced anxiety disorders. The BNST contains three neuronal types, Type I-III neurons. However, little is known about 5-HT receptor subtypes mRNA expression in these neurons, or whether it can be modulated by stress. Whole-cell patch clamp recording from Type I-III neurons was used in conjunction with single cell reverse transcriptase polymerase chain reaction (RT-PCR) to characterize 5-HT receptor mRNA expression, and examine the effects of stress on this expression. We report that Type I neurons expressed mRNA transcripts predominantly for 5-HT(1A) and 5-HT(7) receptors. Type II neurons expressed transcripts for every 5-HT receptor except the 5-HT(2C) receptor. Type II neurons were divided into three sub-populations: Type IIA in which transcripts for 5-HT(3) and 5-HT(7) receptors predominate, Type IIB that mainly express 5-HT(1B) and 5-HT(4) receptor transcripts, and Type IIC in which transcripts for 5-HT(1A) and 5-HT(2A) receptors predominate. Type III neurons were also subdivided into two sub-populations; one that predominantly expressed transcripts for 5-HT(1A), 5-HT(1B) and 5-HT(2A) receptors, and another that mainly expressed transcripts for 5-HT(2C) receptor. Unpredictable shock stress (USS) caused a long-lasting increase in anxiety-like behavior, and a concomitant decrease in 5-HT(1A) transcript expression in Type I-III neurons, as well as an up-regulation of a transcriptional repressor of 5-HT(1A) gene expression, deformed epidermal autoregulatory factor 1 (Deaf-1). Significantly USS decreased 5-HT(1A) protein level, and increased the level of Deaf-1. USS also increased 5-HT(1B) transcript expression in Type III neurons, as well as 5-HT(7) expression in Type I and II neurons. These data suggest that cell type-specific disruption of 5-HT receptor expression in BNST(ALG) neurons may contribute to stress-induced anxiety disorders. PMID:22922122

Hazra, R; Guo, J D; Dabrowska, J; Rainnie, D G

2012-08-23

381

Deposition of Cryptosporidium parvum oocysts in porous media: a synthesis of attachment efficiencies measured under varying environmental conditions.  

PubMed

An extensive set of column experiments was performed with freshly harvested Cryptosporidium parvum oocysts to evaluate the effects of solution chemistry, surface coatings, interactions with other suspended particles, and pore fluid velocity on the fate and transport of this widely occurring waterborne pathogen in sandy porous media. We synthesized our data set with a comprehensive literature survey of similar experiments, to compute attachment (collision) efficiencies (?) used in colloid filtration theory (CFT) using three models for the single collector efficiency (?) across a wide range of experimental conditions. Most prior experiments have observed the transport of surface-treated, sterile C. parvum oocyst in porous media. Our column data confirm for freshly harvested oocysts that the presence of iron coatings on the sand medium and the presence of suspended illite clay drastically enhance oocyst deposition. Increasing ionic strength and decreasing pH also systematically enhance the attachment efficiency. Attachment efficiency decreases only at a very high ionic strength, most likely as a result of steric repulsion and possibly other changes in oocyst surface properties. Attachment efficiencies vary with fluid flow rate but without showing specific trends. We found that the computed attachment efficiency across all reported experiments could be reliably estimated using a regression model based on parameters related to ionic strength and pH. The regression model performed better with the Nelson-Ginn ? model and Tufenkji-Elimelech ? model than with the Rajagopalan-Tien ? model. When CFT is used in environmental assessments, the proposed regression model provides a practical estimator for attachment efficiencies of C. parvum oocyst deposition in porous media for a variety of environmental conditions unfavorable to attachment. PMID:22861686

Park, Yeonjeong; Atwill, E Robert; Hou, Lingling; Packman, Aaron I; Harter, Thomas

2012-08-21

382

Temporal variation of nonstructural carbohydrates in montane conifers: similarities and differences among developmental stages, species and environmental conditions.  

PubMed

Nonstructural carbohydrates (NSCs) are commonly used to assess the balance of carbon sources and sinks in plants. A notable application of this approach has been tests of hypotheses on carbon limitations of trees at their upper altitudinal limits, near the alpine. How NSCs vary in time is not well known in conifers during their critical seedling stage, despite the importance of knowing the temporal variations of NSCs to use snapshot measurements of NSCs to assess carbon balance. We measured NSCs in needles, separately as soluble sugars and starch; (1) over diurnal periods in seedlings of Pseudotsuga menziesii (Mirb.) Franco (a timberline species that does not occur up to treeline), (2) throughout the growth season in the seedlings of P. menziesii and Abies lasiocarpa (Hook.) Nutt. (a species that does occur up to treeline) growing along an elevation gradient in the timberline ecotone and furthermore (3) compared seedlings and co-occurring adults to assess variation with developmental stage. We also compared NSCs in seedlings grown under field or laboratory conditions to separate environmental from intrinsic factors affecting NSCs during early emergence. Diurnal variations in NSCs were minimal, especially when compared to seasonal variation, and were detectable mainly in relatively small midday maxima of soluble sugar concentrations. Seasonal patterns of NSCs were generally (and surprisingly) similar among field and laboratory seedlings and adults. Seasonal patterns of NSCs were dominated by progressive increases in soluble sugars until winter, and by early-season peaks in starch. Nonetheless, notable differences were detectable among ages, species and environmental conditions in (1) the timing and extent of the early-season maxima of starch and (2) the extent of the late-season maxima of soluble sugars. These differences in NSCs likely correspond with ecophysiologically relevant differences in carbon balance that could affect growth and survival of trees growing in the timberline ecotone. PMID:19203971

Bansal, Sheel; Germino, Matthew J

2009-01-28

383

Effects of Individual Pre-Fledging Traits and Environmental Conditions on Return Patterns in Juvenile King Penguins  

PubMed Central

Despite the importance of early life stages in individuals' life history and population dynamics, very few studies have focused on the constraints to which these juvenile traits are subjected. Based on 10 years of automatic monitoring of over 2500 individuals, we present the first study on the effects of environmental conditions and individual pre-fledging traits on the post-fledging return of non-banded king penguins to their natal colony. Juvenile king penguins returned exclusively within one of the three austral summers following their departure. A key finding is that return rates (range 68–87%) were much higher than previously assumed for this species, importantly meaning that juvenile survival is very close to that of adults. Such high figures suggest little juvenile dispersal, and selection occurring mostly prior to fledging in king penguins. Pre-fledging conditions had a strong quadratic impact on juvenile return rates. As expected, cohorts reared under very unfavourable years (as inferred by the breeding success of the colony) exhibited low return rates but surprisingly, so did those fledged under very favourable conditions. Juvenile sojourns away from the colony were shorter under warm conditions and subsequent return rates higher, suggesting a positive effect of climate warming. The longer the post-fledging trip (1, 2 or 3 years), the earlier in the summer birds returned to their natal colony and the longer they stayed before leaving for the winter journey. The presence of juveniles in the colony was more than twice the duration required for moulting purposes, yet none attempted breeding in the year of their first return. Juvenile presence in the colony may be important for acquiring knowledge on the social and physical colonial environment and may play an important part in the learning process of mating behaviour. Further studies are required to investigate its potential implications on other life-history traits such as recruitment age.

Saraux, Claire; Viblanc, Vincent A.; Hanuise, Nicolas; Le Maho, Yvon; Le Bohec, Celine

2011-01-01

384

Chemical and Physical Environmental Conditions Underneath Mat- and Canopy-Forming Macroalgae, and Their Effects on Understorey Corals  

PubMed Central

Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m?2 dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading). The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation.

Hauri, Claudine; Fabricius, Katharina E.; Schaffelke, Britta; Humphrey, Craig

2010-01-01

385

Changes in lipid composition of copepods and Euphausia superba associated with diet and environmental conditions in the marginal ice zone, Bellingshausen Sea, Antarctica  

Microsoft Academic Search

The effect of varying diet and environmental conditions at the Marginal Ice Zone (MIZ) on the fatty acid and hydrocarbon compositions of five species of copepod and krill, Euphausia superba, was investigated. Zooplankton at the MIZ experienced a range of conditions, from a low algal biomass (mainly flagellates) under pack-ice to a spring bloom dominated by diatoms in the open

G. C Cripps; H. J Hill

1998-01-01

386

Building environmental performance model for variable air volume systems in air-conditioned high-rise buildings in sub-tropical climates  

Microsoft Academic Search

As Hong Kong's economy prospered in the 1950s, air-conditioning became the norm as part of the building services designs for office buildings. Unfortunately, Cantonese speakers translated the term 'air conditioning system' into something which literally meant 'cold air system'. The concept of indoor environmental quality (IEQ) was never properly rooted in the minds of users. Since the energy crisis of

Kwok Wai Mui

2002-01-01

387

Influence of Variable Environmental Conditions on Presence and Concentration of Energetic Chemicals Near Soil Surface in the Vadoze Zone  

NASA Astrophysics Data System (ADS)

Many explosive-related compounds (ERCs) are found near the soil-atmospheric surface in sites containing buried explosive devices, such as landmines and unexploded ordnance, detonation-residual, and munitions residues from explosive manufacturing facilities. Accurate assessment of the fate and transport processes is essential for predicting their movement to the surface, groundwater, or any other important environmental compartment. The transport processes controlling the direction and magnitude of the movement, and chemical and physical processes controlling the fate of the chemicals vary with environmental conditions. This research addresses the effect of variable rainfall, evaporation, temperature, and solar radiation on fate and transport of 2,4,6-Trinitrotoluene (TNT), 2,4-Dinitrotoluene (DNT), and other related chemicals in partially saturated soil. Experiments have been conducted in a laboratory-scale 3D SoilBed placed inside an environmental chamber equipped with rainfall and solar radiation simulators, and temperature control settings. The SoilBed was packed with a sandy soil. Experiments have been conducted by burying a TNT/DNT source, simulating a landmine, and applying different rainfall and light radiation cycles while monitoring DNT, TNT, and other related ERCs solute concentrations temporally and spatially within the SoilBed. Experiments include different source characteristics, rainfall intensities, temperatures, and radiation cycles to evaluate their effect on the detection and movement of ERC in soils in both aqueous and vapor phases. Temporal and spatial data has been analyzed comparatively and quantitatively. Comparative analysis was developed using surfer®- and voxler®-generated images and 3D visualization models applying spatial interpolation and masking methods. Single and multi-variable statistical analysis has been employed to determine the most important factors affecting the fate, transport and detection of ERC near soil-atmospheric surfaces. Results show that rainfall, radiation, and temperature variations influence the presence, transport, and concentrations of TNT and DNT near the soil surface. Higher concentrations are observed near the end of rainfall events, both in the aqueous and gaseous phases. Higher rainfall intensity results in higher presence and concentrations. Lower TNT and DNT concentrations than their solubility limit indicate rate-limited mass transfer, dissolution limitations, and dilution processes. Radiation events and higher atmospheric temperatures result in greater presence and concentrations of DNT and TNT, indicating influence of these factors on fate and transport processes. TNT degradation by-products measured mostly in the upper segments of the SoilBed, suggest degradation processes resulting from radiation-induced conditions near the soil-atmospheric surface. Although the ERC source consists of equal mass of TNT and DNT, greater detection density and concentrations are observed for DNT. A generalized linear mixed statistical model has been applied to quantify the effect of environmental conditions on ERC detection and concentrations. The statistical analysis indicates that rainfall events and related water contents are the most influential factors affecting the presence and concentrations of ERCs in the aqueous and gaseous phase. Solar radiation, and related heat flux, is the second most influential parameter. Although atmospheric temperature influence the presence and concentration of ERCs in soils, it is the least influential parameter.

Anaya, A. A.; Padilla, I. Y.

2008-12-01

388

Environmental Conditions during Breeding Modify the Strength of Mass-Dependent Carry-Over Effects in a Migratory Bird.  

PubMed

In many animals, processes occurring in one season carry over to influence reproductive success and survival in future seasons. The strength of such carry-over effects is unlikely to be uniform across years, yet our understanding of the processes that are capable of modifying their strength remains limited. Here we show that female light-bellied Brent geese with higher body mass prior to spring migration successfully reared more offspring during breeding, but only in years where environmental conditions during breeding were favourable. In years of bad weather during breeding, all birds suffered reduced reproductive output irrespective of pre-migration mass. Our results suggest that the magnitude of reproductive benefits gained by maximising body stores to fuel breeding fluctuates markedly among years in concert with conditions during the breeding season, as does the degree to which carry-over effects are capable of driving variance in reproductive success among individuals. Therefore while carry-over effects have considerable power to drive fitness asymmetries among individuals, our ability to interpret these effects in terms of their implications for population dynamics is dependent on knowledge of fitness determinants occurring in subsequent seasons.  PMID:24143258

Harrison, Xavier A; Hodgson, David J; Inger, Richard; Colhoun, Kendrew; Gudmundsson, Gudmundur A; McElwaine, Graham; Tregenza, Tom; Bearhop, Stuart

2013-10-15

389

Environmental Conditions during Breeding Modify the Strength of Mass-Dependent Carry-Over Effects in a Migratory Bird  

PubMed Central

In many animals, processes occurring in one season carry over to influence reproductive success and survival in future seasons. The strength of such carry-over effects is unlikely to be uniform across years, yet our understanding of the processes that are capable of modifying their strength remains limited. Here we show that female light-bellied Brent geese with higher body mass prior to spring migration successfully reared more offspring during breeding, but only in years where environmental conditions during breeding were favourable. In years of bad weather during breeding, all birds suffered reduced reproductive output irrespective of pre-migration mass. Our results suggest that the magnitude of reproductive benefits gained by maximising body stores to fuel breeding fluctuates markedly among years in concert with conditions during the breeding season, as does the degree to which carry-over effects are capable of driving variance in reproductive success among individuals. Therefore while carry-over effects have considerable power to drive fitness asymmetries among individuals, our ability to interpret these effects in terms of their implications for population dynamics is dependent on knowledge of fitness determinants occurring in subsequent seasons. 

Harrison, Xavier A.; Hodgson, David J.; Inger, Richard; Colhoun, Kendrew; Gudmundsson, Gudmundur A.; McElwaine, Graham; Tregenza, Tom; Bearhop, Stuart

2013-01-01

390

The first "space" vegetables have been grown in the "SVET" greenhouse by means of controlled environmental conditions.  

PubMed

The paper describes the project "SVET"--the creating of a small dimensions space greenhouse of new generation. By means of minicomputer, "SVET" is full-automatic operating and controlling environmental conditions system in the higher plants growth unit. A number of studies have selected the radish and cabbage vegetables as a potentially important crop for CELSS (short term cycle of vegetation). The "SVET" space greenhouse has been mounted on the "CRYSTAL" technological module which docked to the "MIR" orbital space station on June 10, 1990. Soviet cosmonauts Balandin and Solovyov started the first experiments with the greenhouse on June 15, 1990. The preliminary results of the seeds cultivation for the first 54-days period in "SVET" are presented. Morphometrical characteristics of the plants, brought back to the Earth are given. The vegetation peculiarities, such as the plants growth and the development slowing-down, or the dry substance contents raising are noted. For the first time, the root crop of radish plants at microgravity conditions, are produced. Characteristics of controlled plants' environment parameters and an estimation of functional properties of control and regulation systems of the "SVET" greenhouse in space flight according to telemetry data is given. PMID:11541047

Ivanova, T N; Bercovich YuA; Mashinskiy, A L; Meleshko, G I

1992-04-01

391

Impact of environmental housing conditions on the emotional responses of mice deficient for nociceptin/orphanin FQ peptide precursor gene.  

PubMed

Nociceptin/orphanin FQ (N/OFQ) is a newly discovered neuropeptide that has been implicated in the neurobiological regulation of the behavioral responses to stress and fear. To investigate the role of this peptide in the expression of stress/anxiety-related behaviors in mice, a gene targeting approach to disrupt N/OFQ in the pre-proN/OFQ gene was used. The impact of environmental housing conditions (single and social housing) was assessed on N/OFQ-knockout male and female mice in different experimental paradigms known to trigger distinctive types of stress and anxiety states. Neurological examination of homozygous mutant adult animals indicated that basic neurological functions (vision, audition, olfaction, tactile and pain sensitivity, motor performances) were normal. When housed individually, N/OFQ-knockout animals displayed responses similar to control animals in behavioral tests of emotional reactivity (behavioral despair, locomotor activity, light-dark preference, and acoustic startle tests). In contrast, increased emotional responses were detected when individually housed mice were crowded together (five per cage) under conditions of competitive access to food, water, space, and social contacts. Under those conditions, male mice deficient for N/OFQ developed greater home-cage aggression and increased fear/anxiety-like behaviors in the light-dark and acoustic startle tests, when compared to their wild-type littermates. Group-housed female mutants also showed higher level of anxiety in the acoustic startle test, but needed additional restrain stress to express detectable levels of anxiety in the light-dark test. These data indicate a clear environment-induced rise in fear reactions of N/OFQ-knockout mice. They further suggest that N/OFQ system is essential for development of adequate coping strategies to acute and chronic stress. PMID:12946601

Ouagazzal, A-M; Moreau, J-L; Pauly-Evers, M; Jenck, F

2003-09-15

392

Near-bed environmental conditions influencing cold-water coral growth on Viosca Knoll, Gulf of Mexico  

NASA Astrophysics Data System (ADS)

During recent decades research has shown that cold-water coral (CWC) ecosystems are widely distributed on the margins of the Atlantic Ocean, representing the most species rich ecosystems in the upper bathyal zone. On the European continental margin and the continental slope from North Carolina to Florida, CWCs have formed large reef and mound structures. Presently detailed studies on the environmental constraints in CWC areas are limited to the NE Atlantic. This is the first study showing long-term environmental variability in a CWC habitat in the West Atlantic. The most extensive CWC area known in the Gulf of Mexico is found on the Viosca Knoll (480 m), located in the vicinity of the Mississippi River. This source dominates sedimentation patterns, discharging large amounts of sediments and dispersing organic matter and nutrients. In the coral area, CTD transects were made and benthic landers were deployed for a period of 12 months to identify near-bed environmental conditions, seasonal variability and the forcing mechanisms of particle supply. The importance of studying the functioning of deep water ecosystems was underpinned by the recent Deepwater Horizon oil spill, which might pose a risk for the CWC ecosystems. CTD transects showed an oxygen minimum zone at the depth of the corals. Long term deployments of landers revealed intra-annual temperature (6.5-11.6 °C) and salinity fluctuations, which co-vary during the year. Food supply appears not to be driven by surface processes due to low fluorescence (except for two periods in April and June), but an indirect mechanism of transport may be a 24 hour diel vertical migration of zooplankton. The average current speed in the area varies at around 8 cms-1, whilst peak current speeds were recorded up to 38 cms-1. East-west currents are strongest in the area corresponding with flow along isobaths. During westward flow, the amount of particles in the water column increases, while during eastward flow clearer water is transported to the area. Sediment trap samples show a similar pattern and high mass fluxes are found, varying between 1.1-4.5 gm-2day-1. High mass fluxes and turbidity values can be related to an increased input of material coming from the Mississippi River. The environmental conditions on Viosca Knoll resemble those recorded in CWC areas on the European margin. Even though oxygen values are low and high mass fluxes were recorded, the CWC ecosystem thrives at present. The proximity of the area to the Mississippi River may benefit the corals by increasing the food supply. Migration of zooplankton and episodes of fresh particle supply from surface water form the mechanisms of food delivery, influencing CWC growth. Subsequently baffling of particles between the coral framework likely increases lateral extension and reef growth.

Mienis, F.; Duineveld, G.; Davies, A. J.; Weering, T. V.; Ross, S.; Roberts, M.; Seim, H.

2010-12-01

393

Women, but not men, report increasingly more pain during repeated (un)predictable painful electrocutaneous stimulation: Evidence for mediation by fear of pain.  

PubMed

An abundance of animal research suggests that fear inhibits pain whereas anxiety increases it. Human studies on this topic are more scarce, and the existing evidence seems rather inconsistent. Therefore, we aimed to investigate the divergent effects of both negative emotional states-that is, pain-related fear and anxiety on pain sensitivity and unpleasantness. Possible sex-related differences were also under investigation, as well as the potential mediational role of fear of movement-related pain on the differences in pain intensity and unpleasantness between both sexes. We employed a voluntary joystick movement paradigm using movements as conditioned stimuli (CSs) and a painful electrocutaneous stimulus as the unconditioned stimulus. Healthy participants received predictable shocks in one condition and unpredictable shocks in another condition. The former procedure is known to induce fear of movement-related pain to the CS+ movement (movement consistently followed by pain), whereas the latter procedure induces (contextual) pain-related anxiety. Results showed that fear of movement-related pain indeed resulted in decreased pain intensity/unpleasantness ratings, while pain-related anxiety led to increased pain intensity/unpleasantness reports. Further, the anticipated sex difference was modulated by time. That is, women gradually reported more pain/unpleasantness, whereas men do not show such a sensitization effect. Moreover, this sex-specific sensitization is partially mediated by (conditioned) fear of movement-related pain. Women also report increasingly more fear of pain over conditioning blocks, while men do not. These results might be interesting in the light of the overrepresentation of women in a number of clinical pain conditions as well as anxiety disorders. PMID:22401700

Meulders, Ann; Vansteenwegen, Debora; Vlaeyen, Johan W S

2012-03-07

394

A holistic evaluation of risks in coastal regions under changing climatic, environmental and socioeconomic conditions: the Theseus Decision Support System.  

NASA Astrophysics Data System (ADS)

There is a general acceptance that global changes associated with natural hazards and socioeconomic processes are occurring at a faster pace than ever, with deep implications in terms of risk exposure and environmental impact. The capacity of coastal areas to adapt and react to these changes will be a key factor in the future preservation of life standards and represents a great challenge for politicians, scientists and professionals at any level. Within the large scope of Theseus Project (EU 7th Framework Program), one of the main objectives is to design a tool to help decision makers in defining optimal strategies to minimize risks within a certain city or coastal area in a three-fold sense: economic losses, human damages and environmental impacts. The resulting software, the Theseus-DSS, links the most relevant physical processes (waves, sea-levels, hard and soft structures, coastal erosion and inland flooding) with the potential impact zones (marine and inland), considering their functions (ecosystems) and uses (economic units), and the dependence of this functions and uses upon the prevailing physical conditions. The new software tries to fill a gap among the existing tools, based on the following pillars: • Seamless integration of disciplines: physics, engineering, ecology, social sciences and economy. • Intermediate spatial scales (1- 10 km) and medium-to- long time spans (1-10 years). • Decision-making based on a balance between deterministic models and expert, discussion-based assumptions. The user of the Theseus-DSS will be able either to check the consequences of predefined scenarios at a particular study site, or to create user-defined scenarios, run them and compare the results with other scenarios. The results are expressed, locally and at an aggregate level, in the three aforementioned dimensions: economic losses (€/year), mean annual expected live losses (persons/year) and impact on habitats (null, low, medium and high).

Losada, I. J.; Garcia Alonso, E.; Mendez, F. J.; Zanuttigh, B.; Nicholls, R. J.; Thompson, R.; Vanderlinden, J. P.; Fernandez, F.; Ondiviela, B.; Diaz-Simal, P.; Bagli, S.

2012-04-01

395

Mitigation potential of horizontal ground coupled heat pumps for current and future climatic conditions: UK environmental modelling and monitoring studies  

NASA Astrophysics Data System (ADS)

An increased uptake of alternative low or non-CO2 emitting energy sources is one of the key priorities for policy makers to mitigate the effects of environmental change. Relatively little work has been undertaken on the mitigation potential of Ground Coupled Heat Pumps (GCHPs) despite the fact that a GCHP could significantly reduce CO2 emissions from heating systems. It is predicted that under climate change the most probable scenario is for UK temperatures to increase and for winter rainfall to become more abundant; the latter is likely to cause a general rise in groundwater levels. Summer rainfall may reduce considerably, while vegetation type and density may change. Furthermore, recent studies underline the likelihood of an increase in the number of heat waves. Under such a scenario, GCHPs will increasingly be used for cooling as well as heating. These factors will affect long-term performance of horizontal GCHP systems and hence their economic viability and mitigation potential during their life span ( 50 years). The seasonal temperature differences encountered in soil are harnessed by GCHPs to provide heating in the winter and cooling in the summer. The performance of a GCHP system will depend on technical factors (heat exchanger (HE) type, length, depth, and spacing of pipes), but also it will be determined to a large extent by interactions between the below-ground parts of the system and the environment (atmospheric conditions, vegetation and soil characteristics). Depending on the balance between extraction and rejection of heat from and to the ground, the soil temperature in the neighbourhood of the HE may fall or rise. The GROMIT project (GROund coupled heat pumps MITigation potential), funded by the Natural Environment Research Council (UK), is a multi-disciplinary research project, in collaboration with EarthEnergy Ltd., which aims to quantify the CO2 mitigation potential of horizontal GCHPs. It considers changing environmental conditions and combines model predictions of soil moisture content and soil temperature with measurements at different GCHP locations over the UK. The combined effect of environment dynamics and horizontal GCHP technical properties on long-term GCHP performance will be assessed using a detailed land surface model (JULES: Joint UK Land Environment Simulator, Meteorological Office, UK) with additional equations embedded describing the interaction between GCHP heat exchangers and the surrounding soil. However, a number of key soil physical processes are currently not incorporated in JULES, such as groundwater flow, which, especially in lowland areas, can have an important effect on the heat flow between soil and HE. Furthermore, the interaction between HE and soil may also cause soil vapour and moisture fluxes. These will affect soil thermal conductivity and hence heat flow between the HE and the surrounding soil, which will in turn influence system performance. The project will address these issues. We propose to drive an improved version of JULES (with equations to simulate GCHP exchange embedded), with long-term gridded (1 km) atmospheric, soil and vegetation data (reflecting current and future environmental conditions) to reliably assess the mitigation potential of GCHPs over the entire domain of the UK, where uptake of GCHPs has been low traditionally. In this way we can identify areas that are most suitable for the installation of GCHPs. Only then recommendations can be made to local and regional governments, for example, on how to improve the mitigation potential in less suitable areas by adjusting GCHP configurations or design.

García González, Raquel; Verhoef, Anne; Vidale, Pier Luigi; Gan, Guohui; Wu, Yupeng; Hughes, Andrew; Mansour, Majdi; Blyth, Eleanor; Finch, Jon; Main, Bruce

2010-05-01

396

Scope and Methods of Environmental Testing of Double-Base Propellant Rocket Motors: Choice of Conditions and Interpretation of Results.  

National Technical Information Service (NTIS)

Environmental testing problems are considered, primarily from the standpoint of the propellant chemist. Environments are defined and the significant aspects of motor design and possible failure modes considered. Preliminary tests, and environmental tests ...

J. Gooding

1973-01-01

397

Environmental conditions, rather than season, determine torpor use and temperature selection in large mouse-eared bats (Myotis myotis).  

PubMed

We tested whether food availability, thermal environment and time of year affect torpor use and temperature selection in the large mouse-eared bat (Myotis myotis) in summer and winter. Food-deprived bats were torpid longer than bats offered food ad libitum. Bats placed in a gradient of low (0 degrees C-25 degrees C) ambient temperatures (T(a)) spent more time in torpor than bats in a gradient of high (7 degrees C-43 degrees C) T(a)'s. However, we did not observe seasonal variations in the use of torpor. Moreover, even when food deprived in winter, bats never entered prolonged torpor at T(a)'s characteristic of their natural hibernation. Instead, bats preferred shallow torpor at relatively high T(a), but they always maintained a difference between body and ambient temperatures of less than 2 degrees C. Calculations based on respirometric measurements of metabolic rate showed that food deprived bats spent less energy per unit of time in torpor than fed individuals, even when they entered torpor at higher T(a)'s. We conclude that T(a) likely serves as a signal of food availability and daily torpor is apparently an adaptation to unpredictable changes in food availability, such as its decrease in summer or its increase in winter. Thus, we interpret hibernation to be a second step in the evolution of heterothermy in bats, which allows survival in seasonal environments. PMID:16891137

Wojciechowski, Micha? S; Jefimow, Ma?gorzata; Tegowska, Eugenia

2006-06-29

398

Emissions of volatile organic compounds from Quercus ilex L. measured by Proton Transfer Reaction Mass Spectrometry under different environmental conditions  

NASA Astrophysics Data System (ADS)

Volatile organic compound (VOC) emissions of the Mediterranean holm oak (Quercus ilex L.) were investigated using a fast Proton Transfer Reaction Mass Spectrometry (PTR-MS) instrument for analysis. This technique is able to measure compounds with a proton affinity higher than water with a high time resolution of 1 s per compound. Hence nearly all VOCs can be detected on-line. We could clearly identify the emission of methanol, acetaldehyde, ethanol, acetone, acetic acid, isoprene, monoterpenes, toluene, and C10-benzenes. Some other species could be tentatively denominated. Among these are the masses 67 (cyclo pentadiene), mass 71 (tentatively attributed to methyl vinyl ketone (MVK) and metacrolein (MACR)), 73 (attributed to methyl ethyl ketone (MEK)), 85 (C6H12 or hexanol), and 95 (vinylfuran or phenol). The emissions of all these compounds (identified as well as nonidentified) together represent 99% of all masses detected and account for a carbon loss of 0.7-2.9% of the net photosynthesis. Of special interest was a change in the emission behavior under changing environmental conditions such as flooding or fast light/dark changes. Flooding of the root system caused an increase of several VOCs between 60 and 2000%, dominated by the emission of ethanol and acetaldehyde, which can be explained by the well described production of ethanol under anoxic conditions of the root system and the recently described subsequent transport and partial oxidation to acetaldehyde within the green leaves. However, ethanol emissions were dominant. Additionally, bursts of acetaldehyde with lower ethanol emission were also found under fast light/dark changes. These bursts are not understood.

Holzinger, R.; Sandoval-Soto, L.; Rottenberger, S.; Crutzen, P. J.; Kesselmeier, J.

2000-08-01

399

Hold time, strain rate and environmental effects on near eutectic Sn-Pb under conditions of thermomechanical fatigue  

SciTech Connect

We present results that correlate microstructure and mechanical evolution to variations of deformation rate, hold time and environmental effects on the thermomechanical fatigue (TMF) behavior of 60Sn-40Pb solder. The results are used to define valid conditions for performing accelerated TMF tests. TMF tests at deformation rates of 5.6{times}10{sup {minus}4}s{sup {minus}1}, 2.8{times}10{sup {minus}4}s{sup {minus}1} and 2.1{times}10{sup {minus}4}s{sup {minus}1} were performed. Deformation rates greater than 2.8{times}10{sup {minus}4}s{sup {minus}1} result in fewer cycles to failure. At low deformation rates, the microstructure heterogeneously coarsens at cell boundaries. At higher rates, the deformation mechanism changes, and heterogeneous coarsening occurs at a strain concentration in the joint, independent of the microstructure. TMF tests with hold times of 0, 3 and 6 min. at the temperature extremes were performed. At hold times 3 min. or longer the damage at cell boundaries is annealed, resulting in heterogeneous coarsening. With no hold times the TMF life was greatly enhanced as a result of limited coarsening. The effect of the oxygen environment was explored. The TMF life in the presence of oxygen was found to be extended. Valid acceleration conditions for a TMF test of solder are: a deformation rate of 2.8{times}10{sup {minus}4}s{sup {minus}1} or lower, with hold times of 3 mn. or longer.

Frear, D.R.; Jones, W.B.; Sorensen, N.R.

1992-01-01

400

Hold time, strain rate and environmental effects on near eutectic Sn-Pb under conditions of thermomechanical fatigue  

SciTech Connect

We present results that correlate microstructure and mechanical evolution to variations of deformation rate, hold time and environmental effects on the thermomechanical fatigue (TMF) behavior of 60Sn-40Pb solder. The results are used to define valid conditions for performing accelerated TMF tests. TMF tests at deformation rates of 5.6{times}10{sup {minus}4}s{sup {minus}1}, 2.8{times}10{sup {minus}4}s{sup {minus}1} and 2.1{times}10{sup {minus}4}s{sup {minus}1} were performed. Deformation rates greater than 2.8{times}10{sup {minus}4}s{sup {minus}1} result in fewer cycles to failure. At low deformation rates, the microstructure heterogeneously coarsens at cell boundaries. At higher rates, the deformation mechanism changes, and heterogeneous coarsening occurs at a strain concentration in the joint, independent of the microstructure. TMF tests with hold times of 0, 3 and 6 min. at the temperature extremes were performed. At hold times 3 min. or longer the damage at cell boundaries is annealed, resulting in heterogeneous coarsening. With no hold times the TMF life was greatly enhanced as a result of limited coarsening. The effect of the oxygen environment was explored. The TMF life in the presence of oxygen was found to be extended. Valid acceleration conditions for a TMF test of solder are: a deformation rate of 2.8{times}10{sup {minus}4}s{sup {minus}1} or lower, with hold times of 3 mn. or longer.

Frear, D.R.; Jones, W.B.; Sorensen, N.R.

1992-04-01

401

Difference in keratinase activity of dermatophytes at different environmental conditions is an attribute of adaptation to parasitism.  

PubMed

Dermatophytes are a group of morphologically and physiologically related moulds, which cause well-defined infection called dermatophytosis. The enzymatic ability of fungi to decompose keratin has long been interpreted as a key innovation in the evolution of animal dermatology. In the present study, keratinase activity profile among Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis and Microsporum gypseum isolated on keratin substrates such as human hair, human nail and chicken feather at variable environmental conditions of temperature, pH and metal ions was elucidated. All the above-mentioned fungal strains were isolated from soil using To-KA-Va baiting technique and keratinolytic activity was measured spectrophotometrically. In the temperature range of 30-40 °C and slightly alkaline pH (7.0-8.0), Trichophyton produced the highest activity of keratinase. It can be presumed that high enzyme production of Trichophyton species at normal body temperature range and pH could be an attribute for obligate anthropization in some dermatophytes. PMID:22032519

Sharma, Anima; Chandra, Subhash; Sharma, Meenakshi

2011-10-27

402

Community Composition, Toxigenicity, and Environmental Conditions during a Cyanobacterial Bloom Occurring along 1,100 Kilometers of the Murray River  

PubMed Central

A cyanobacterial bloom impacted over 1,100 km of the Murray River, Australia, and its tributaries in 2009. Physicochemical conditions in the river were optimal to support a bloom at the time. The data suggest that at least three blooms occurred concurrently in different sections of the river, with each having a different community composition and associated cyanotoxin profile. Microscopic and genetic analyses suggested the presence of potentially toxic Anabaena circinalis, Microcystis flos-aquae, and Cylindrospermopsis raciborskii at many locations. Low concentrations of saxitoxins and cylindrospermopsin were detected in Anabaena and Cylindrospermopsis populations. A multiplex quantitative PCR was used, employing novel oligonucleotide primers and fluorescent TaqMan probes, to examine bloom toxigenicity. This single reaction method identified the presence of the major cyanotoxin-producing species present in these environmental samples and also quantified the various toxin biosynthesis genes. A large number of cells present throughout the bloom were not potential toxin producers or were present in numbers below the limit of detection of the assay and therefore not an immediate health risk. Potential toxin-producing cells, possessing the cylindrospermopsin biosynthesis gene (cyrA), predominated early in the bloom, while those possessing the saxitoxin biosynthesis gene (sxtA) were more common toward its decline. In this study, the concentrations of cyanotoxins measured via enzyme-linked immunosorbent assay (ELISA) correlated positively with the respective toxin gene copy numbers, indicating that the molecular method may be used as a proxy for bloom risk assessment.

Al-Tebrineh, Jamal; Merrick, Chester; Ryan, David; Humpage, Andrew; Bowling, Lee

2012-01-01

403

Serotonin transporter gene polymorphism (5-HTTLPR), environmental conditions, and developing negative emotionality and fear in early childhood.  

PubMed

Studies on neural and behavioral correlates of the serotonin transporter gene polymorphism (5-HTTLPR) strongly suggested interaction effects between the 5-HTTLPR genotype and environmental conditions on infant emotionality development. However, empirical studies that involve human infants are rare. The present study thus analyzed the interaction of the 5-HTTLPR genotype with the quality of maternal parenting behavior on the development of negative emotionality and fear in infancy. In a sample of 69 healthy firstborn infants, negative emotionality and fear were assessed at 4, 8, and 12 months using a multi-method approach. The quality of previous parenting has been operationalized as the quality of the mother-infant attachment relationship measured by the strange situation procedure at 18 months. Corresponding to hypotheses, to their caregiver insecurely attached infants who were homozygous for the s-variant of the 5-HTTLPR genotype developed a high level of negative emotionality and fear. The results thus are in line with the experimental results in the non-human primate model and point to a more pronounced susceptibility of s/s carrying infants to early rearing experiences. PMID:19137235

Pauli-Pott, Ursula; Friedel, Susann; Friedl, Susann; Hinney, Anke; Hebebrand, Johannes

2009-01-10

404

Evaluating open-path FTIR spectrometer data using different quantification methods, libraries, and background spectra obtained under varying environmental conditions  

NASA Astrophysics Data System (ADS)

This paper discussed studies performed in a 35 foot outdoor Teflon exposure chamber in Pittsboro, North Carolina. The purpose of this research was to evaluate open-path FTIR data and compare it to a reference method varying several parameters: the method used for quantification, the library used for quantification, and backgrounds representing varying environmental conditions. The reference method used was GC- FID. The chemical evaluated was toluene over the concentration range of 5-30 ppm. Two different quantification methods were used in this analysis: traditional peak area method and interactive subtraction. All quantification was done manually. Two different libraries were used for quantification: the Hanst library (137 ppm-m toluene) and the EPA library (249 ppm-m) toluene. Several concentration data files were analyzed with the original background and then with subsequent backgrounds obtained from that same day. The subsequent backgrounds contained varying amounts of water vapor. The effect on quantification was evaluated. For concentrations of 20 ppm and below there was no significant difference between the peak area and subtraction method. However, for concentrations greater than 20 ppm, the difference between the two methods increased up to 20%. The difference between the EPA and Hanst libraries was statistically insignificant below 25 ppm. At concentrations greater than 15 ppm, the two libraries deviated and the difference ranged from 5% to 10% with the EPA results being higher. Water vapor was found to drastically impact the quantification. The magnitude of the effect varied between quantification methods and libraries.

Tomasko, Maria S.; Todd, Lori A.

1995-05-01

405

Community composition, toxigenicity, and environmental conditions during a cyanobacterial bloom occurring along 1,100 kilometers of the Murray River.  

PubMed

A cyanobacterial bloom impacted over 1,100 km of the Murray River, Australia, and its tributaries in 2009. Physicochemical conditions in the river were optimal to support a bloom at the time. The data suggest that at least three blooms occurred concurrently in different sections of the river, with each having a different community composition and associated cyanotoxin profile. Microscopic and genetic analyses suggested the presence of potentially toxic Anabaena circinalis, Microcystis flos-aquae, and Cylindrospermopsis raciborskii at many locations. Low concentrations of saxitoxins and cylindrospermopsin were detected in Anabaena and Cylindrospermopsis populations. A multiplex quantitative PCR was used, employing novel oligonucleotide primers and fluorescent TaqMan probes, to examine bloom toxigenicity. This single reaction method identified the presence of the major cyanotoxin-producing species present in these environmental samples and also quantified the various toxin biosynthesis genes. A large number of cells present throughout the bloom were not potential toxin producers or were present in numbers below the limit of detection of the assay and therefore not an immediate health risk. Potential toxin-producing cells, possessing the cylindrospermopsin biosynthesis gene (cyrA), predominated early in the bloom, while those possessing the saxitoxin biosynthesis gene (sxtA) were more common toward its decline. In this study, the concentrations of cyanotoxins measured via enzyme-linked immunosorbent assay (ELISA) correlated positively with the respective toxin gene copy numbers, indicating that the molecular method may be used as a proxy for bloom risk assessment. PMID:22081581

Al-Tebrineh, Jamal; Merrick, Chester; Ryan, David; Humpage, Andrew; Bowling, Lee; Neilan, Brett A

2011-11-11

406

Spatial distribution and biodiversity of macrofauna in the southeast of the Caspian Sea, Gorgan Bay in relation to environmental conditions  

NASA Astrophysics Data System (ADS)

Spatial distribution and biodiversity of macrofauna in the Gorgan Bay, southeast of the Caspian Sea, were studied at fifteen stations in June 2010. Also, depth, temperature, salinity, dissolved oxygen, total organic matter content and sediment particle size were measured in each station. A total 3,356 individuals belonged to eight families and ten species were identified. Polychaeta were numerically dominated groups and Streblospio gynobranchiata, was constant and dominant species with 60.28% of total individuals but Bivalvia with four species had highest species number, though the density of them were low. The maximum density (4,500 ind/m2) was obtained at station 1 while the minimum (411 ind/m2) was observed at station 6. There was not significant correlation between the density of macrofauna with all environmental conditions. In total, six feeding group were considered but surface deposit feeder and deposit feeder were dominant in all stations. The maximum mean species number, diversity, richness, and evenness were obtained, 6.33, 1.46, 1.38 and 0.87, respectively. Based on the M-AMBI and the AMBI classification it seems that bentic environment in Gorgan Bay was not bad but the results of Shannon-Wiener, Margalef and Simpson indices the results were vice versa. In general, the values of the mentioned indices decreased from the western to the eastern part of the bay. Furthermore, the nonmetric multidimensional scaling (nMDS) showed that the structure of the macrofaunal assemblages was divides to six groups.

Taheri, Mehrshad; Foshtomi, Maryam Yazdani; Noranian, Majid; Mira, Seyed Sahab

2012-06-01

407

Late Weichselian and Holocene environmental conditions in Sassenfjorden and Tempelfjorden, Spitsbergen, inferred from multi-proxy analyses  

NASA Astrophysics Data System (ADS)

Multi-proxy analyses including hydrographical, geochemical, foraminferal, lithological and geophysical data from the two fjords Sassenfjorden and Tempelfjorden provide information about modern sedimentary