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1

Long-Term Unpredictable Foraging Conditions and Physiological Stress Response in Mountain Chickadees ( Poecile gambeli)  

Microsoft Academic Search

Birds respond to short-term deterioration in foraging conditions by increasing their plasma level of corticosterone but the physiological effects of long-term deterioration in food supplies are not well known. In resident passerine birds that winter in temperate climates, such as the mountain chickadee (Poecile gambeli), the food supply may be limited and unpredictable over long periods of time. Whether the

Vladimir V. Pravosudov; Alexander S. Kitaysky; John C. Wingfield; Nicola S. Clayton

2001-01-01

2

Environmental Conditions Environmental Conditions  

E-print Network

, developed complex life histories through time that responded to the subbasin's considerable variation in this habitat. Loss of grassland habitat greatly reduced such populations. Today subbasin habitat conditions/optimal) conditions in the year 2050, and examines what future conditions might be expected if no additional future

3

Long-term unpredictable foraging conditions and physiological stress response in mountain chickadees (Poecile gambeli).  

PubMed

Birds respond to short-term deterioration in foraging conditions by increasing their plasma level of corticosterone but the physiological effects of long-term deterioration in food supplies are not well known. In resident passerine birds that winter in temperate climates, such as the mountain chickadee (Poecile gambeli), the food supply may be limited and unpredictable over long periods of time. Whether the long-term limited and unpredictable food supply has an effect on (a) baseline levels of corticosterone and (b) the adrenocortical stress response to a standardized acute stress of handling and restraint in mountain chickadees was assessed. For a period of 94 days, one group of chickadees was maintained on limited and unpredictable food (food-restricted) and the other group was maintained on an ad libitum food supply. The food-restricted birds had significantly higher baseline levels of corticosterone than those maintained on ad libitum food. All birds responded to the acute stressor by an increasing secretion of corticosterone but there were no differences between the treatment groups in their stress response. There was a significant effect of sex on the stress response, with females reaching higher levels of corticosterone and responding at a faster rate than males. These results suggest that permanent resident birds wintering in harsh environments may have elevated levels of corticosterone on a long-term basis. Whereas other factors, such as day length and ambient temperature, may contribute to energetic hardship during the winter, the results showed that limited and unpredictable food alone can trigger significant changes in baseline levels of plasma corticosterone. The potential costs and benefits of long-term increased corticosterone levels in resident food-caching birds are discussed. PMID:11589632

Pravosudov, V V; Kitaysky, A S; Wingfield, J C; Clayton, N S

2001-09-01

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 reported.…

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

2011-01-01

5

Strategic foresight: how planning for the unpredictable can improve environmental decision-making.  

PubMed

Advanced warning of potential new opportunities and threats related to biodiversity allows decision-makers to act strategically to maximize benefits or minimize costs. Strategic foresight explores possible futures, their consequences for decisions, and the actions that promote more desirable futures. Foresight tools, such as horizon scanning and scenario planning, are increasingly used by governments and business for long-term strategic planning and capacity building. These tools are now being applied in ecology, although generally not as part of a comprehensive foresight strategy. We highlight several ways foresight could play a more significant role in environmental decisions by: monitoring existing problems, highlighting emerging threats, identifying promising new opportunities, testing the resilience of policies, and defining a research agenda. PMID:25097098

Cook, Carly N; Inayatullah, Sohail; Burgman, Mark A; Sutherland, William J; Wintle, Brendan A

2014-09-01

6

Environmental conditions and environmental testing  

Microsoft Academic Search

Equipment engineering features, such as construction and production technology are determining factors for the stability of telecommunications equipment. Internationally accepted IEC test methods are available for environmental testing, and now there are special standardized environmental classes and test programs according to the different classes for telecommunications equipment. Developed by ETSI EE1 and recommended for conformance testing. This coordination of the

G. Kovacs

1993-01-01

7

Strategies for Managing When Resources are Unpredictable.  

ERIC Educational Resources Information Center

The effect of unpredictable resources on organizational performance in higher education was examined, along with whether some management strategies are more successful under conditions of relative predictability or unpredictability. Perceptions of administrators about institutional resources and performance were studied, along with the effects of…

Chaffee, Ellen Earle; Krakower, Jack Y.

8

An Unpredictable Environment  

NSDL National Science Digital Library

In this video segment adapted from the International Institute for Sustainable Development, Inuit observers describe how their traditional understanding of weather patterns is being challenged by unpredictable weather behaviors.

Foundation, Wgbh E.

2009-02-25

9

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

PubMed

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

10

FUNDAMENTAL SOURCES OF UNPREDICTABILITY  

Microsoft Academic Search

Abstract: Of course, spontaneous symmetry breaking may give riseto some parameters and even to a choice of solutions, withprobabilities for the various alternatives. I shall deal with thatpossibility further on.)This second assumption is equivalent to stating that there is nonecessary fundamental unpredictability stemming from ignorance of theuniversal dynamical law.3) The density matrix (in the Schrsdinger picture) of the universenear the

Murray Gell-Mann

1996-01-01

11

Prepare for Unpredictable Spring Weather  

MedlinePLUS

... flooding. Whenever warm, moist air collides with cool, dry air, thunderstorms can occur. For much of the world, this happens in spring and summer. Because spring weather is so unpredictable, you may be unprepared when ...

12

Criticality and unpredictability in macroevolution  

Microsoft Academic Search

A recently presented model of large-scale evolution exhibiting self-organized criticality is explored from the dynamical point of view. It is shown that the system approaches the critical state in an anomalous way, with a dynamical exponent z=0. At the same time, the complexity of the interactions among species increases, leading to higher unpredictability. The dynamic evolution is able to generate

Ricard V. Soléand; Susanna C. Manrubia

1997-01-01

13

Unpredictable neonatal stress enhances adult anxiety and alters amygdala gene expression related to serotonin and GABA.  

PubMed

Anxiety-related disorders are among the most common psychiatric illnesses, thought to have both genetic and environmental causes. Early-life trauma, such as abuse from a caregiver, can be predictable or unpredictable, each resulting in increased prevalence and severity of a unique set of disorders. In this study, we examined the influence of early unpredictable trauma on both the behavioral expression of adult anxiety and gene expression within the amygdala. Neonatal rats were exposed to unpaired odor-shock conditioning for 5 days, which produces deficits in adult behavior and amygdala dysfunction. In adulthood, we used the Light/Dark box test to measure anxiety-related behaviors, measuring the latency to enter the lit area and quantified urination and defecation. The amygdala was then dissected and a microarray analysis was performed to examine changes in gene expression. Animals that had received early unpredictable trauma displayed significantly longer latencies to enter the lit area and more defecation and urination. The microarray analysis revealed over-represented genes related to learning and memory, synaptic transmission and trans-membrane transport. Gene ontology and pathway analysis identified highly represented disease states related to anxiety phenotypes, including social anxiety, obsessive-compulsive disorders, post-traumatic stress disorder and bipolar disorder. Addiction-related genes were also overrepresented in this analysis. Unpredictable shock during early development increased anxiety-like behaviors in adulthood with concomitant changes in genes related to neurotransmission, resulting in gene expression patterns similar to anxiety-related psychiatric disorders. PMID:24240029

Sarro, E C; Sullivan, R M; Barr, G

2014-01-31

14

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

NASA Technical Reports Server (NTRS)

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 large as -0.9 have been found between barometric pressure and maser frequency offset. Correlation between maser frequency offset and humidity was small compared to barometric pressure and unpredictable. Analysis of temperature data indicates that in the most current design, temperature does not significantly affect maser frequency offset.

Dragonette, Richard A.; Suter, Joseph J.

1992-01-01

15

Criticality and unpredictability in macroevolution  

NASA Astrophysics Data System (ADS)

A recently presented model of large-scale evolution exhibiting self-organized criticality is explored from the dynamical point of view. It is shown that the system approaches the critical state in an anomalous way, with a dynamical exponent z=0. At the same time, the complexity of the interactions among species increases, leading to higher unpredictability. The dynamic evolution is able to generate phylogenetic fractal trees with dimension close to the one obtained from real taxonomy. Some analytic results are presented and an interesting interpretation of the macroevolutionary process is suggested.

Soléand, Ricard V.; Manrubia, Susanna C.

1997-04-01

16

Immune activity, body condition and human-associated environmental impacts in a wild marine mammal.  

PubMed

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. PMID:23840603

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

2013-01-01

17

10 CFR 50.36b - Environmental conditions.  

Code of Federal Regulations, 2010 CFR

...obligations of the licensee in the environmental area, including, as appropriate...reporting and keeping records of environmental data, and any conditions...environment during operation and decommissioning. These conditions are...information contained in the environmental report or the...

2010-01-01

18

Simulating protein folding in different environmental conditions.  

PubMed

Molecular dynamics simulations have become an invaluable tool in investigating the dynamics of protein folding. However, most computational studies of protein folding assume dilute aqueous simulation conditions in order to reduce the complexity of the system under study and enhance the efficiency. Nowadays, it is evident that environmental conditions encountered in vivo (or even in vitro) play a major role in regulating the dynamics of protein folding especially when one considers the highly condensed environment in the cellular cytoplasm. In order to factor in these conditions, we can utilize the high efficiency of well-designed low resolution (coarse-grained) simulation models to reduce the complexity of these added protein-milieu interactions involving different time and length scales. The goal of this chapter is to describe some recently developed coarse-grained simulation techniques that are specifically designed to go beyond traditional aqueous solvent conditions. The chapter also gives the reader a flavor of the things that we can study using such "smart" low resolution models. PMID:24446362

Homouz, Dirar

2014-01-01

19

Schedule Unpredictability among Early Career Workers  

E-print Network

to current civilian employees in the wage and salaried workforce (N=3,739). We focus on respondents' main job1 Schedule Unpredictability among Early Career Workers in the US Labor Market: A National Snapshot1 labor market.2 This is the first time a measure of advance schedule notice has been included

Scherer, Norbert F.

20

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

21

Crops Models for Varying Environmental Conditions  

NASA Technical Reports Server (NTRS)

New variable environment Modified Energy Cascade (MEC) crop models were developed for all the Advanced Life Support (ALS) candidate crops and implemented in SIMULINK. The MEC models are based on the Volk, Bugbee, and Wheeler Energy Cascade (EC) model and are derived from more recent Top-Level Energy Cascade (TLEC) models. The MEC models simulate crop plant responses to day-to-day changes in photosynthetic photon flux, photoperiod, carbon dioxide level, temperature, and relative humidity. The original EC model allows changes in light energy but uses a less accurate linear approximation. The simulation outputs of the new MEC models for constant nominal environmental conditions are very similar to those of earlier EC models that use parameters produced by the TLEC models. There are a few differences. The new MEC models allow setting the time for seed emergence, have realistic exponential canopy growth, and have corrected harvest dates for potato and tomato. The new MEC models indicate that the maximum edible biomass per meter squared per day is produced at the maximum allowed carbon dioxide level, the nominal temperatures, and the maximum light input. Reducing the carbon dioxide level from the maximum to the minimum allowed in the model reduces crop production significantly. Increasing temperature decreases production more than it decreases the time to harvest, so productivity in edible biomass per meter squared per day is greater at nominal than maximum temperatures, The productivity in edible biomass per meter squared per day is greatest at the maximum light energy input allowed in the model, but the edible biomass produced per light energy input unit is lower than at nominal light levels. Reducing light levels increases light and power use efficiency. The MEC models suggest we can adjust the light energy day-to- day to accommodate power shortages or Lise excess power while monitoring and controlling edible biomass production.

Jones, Harry; Cavazzoni, James; Keas, Paul

2001-01-01

22

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

23

Lunar Polar Environmental Testing: Regolith Simulant Conditioning  

NASA Technical Reports Server (NTRS)

As ISRU system development approaches flight fidelity, there is a need to test hardware in relevant environments. Extensive laboratory and field testing have involved relevant soil (lunar regolith simulants), but the current design iterations necessitate relevant pressure and temperature conditions. Including significant quantities of lunar regolith simulant in a thermal vacuum chamber poses unique challenges. These include facility operational challenges (dust tolerant hardware) and difficulty maintaining a pre-prepared soil state during pump down (consolidation state, moisture retention).For ISRU purposes, the regolith at the lunar poles will be of most interest due to the elevated water content. To test at polar conditions, the regolith simulant must be doped with water to an appropriate percentage and then chilled to cryogenic temperatures while exposed to vacuum conditions. A 1m tall, 28cm diameter bin of simulant was developed for testing these simulant preparation and drilling operations. The bin itself was wrapped with liquid nitrogen cooling loops (100K) so that the simulant bed reached an average temperature of 140K at vacuum. Post-test sampling was used to determine desiccation of the bed due to vacuum exposure. Depth dependent moisture data is presented from frozen and thawed soil samples.Following simulant only evacuation tests, drill hardware was incorporated into the vacuum chamber to test auguring techniques in the frozen soil at thermal vacuum conditions. The focus of this testing was to produce cuttings piles for a newly developed spectrometer to evaluate. This instrument, which is part of the RESOLVE program science hardware, detects water signatures from surface regolith. The drill performance, behavior of simulant during drilling, and characteristics of the cuttings piles will be offered.

Kleinhenz, Julie Elise

2014-01-01

24

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...

25

Assessing United States hurricane damage under different environmental conditions  

E-print Network

Hurricane activity between 1979 and 2011 was studied to determine damage statistics under different environmental conditions. Hurricanes cause billions of dollars of damage every year in the United States, but damage ...

Maheras, Anastasia Francis

2012-01-01

26

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...

27

BENTHIC INDEX OF ENVIRONMENTAL CONDITION OF GULF OF MEXICO ESTUARIES  

EPA Science Inventory

An index was developed for estuarine macrobenthos in the Gulf of Mexico that discriminated between areas with degraded environmental conditions and areas with undegraded or reference conditions. est sites were identified as degraded or reference based on criteria for dissolved ox...

28

Facing the Unpredictable: Automated Adaption of IT Change Plans  

E-print Network

the continuity of the business. In order to tackle this problem, we propose a logically sound approach to adapt to changed management domains is unavoidable because the reliability and business continuityFacing the Unpredictable: Automated Adaption of IT Change Plans for Unpredictable Management

Kemper, Alfons

29

Behavioral and Environmental Conditions associated with Shark Attacks on Humans  

E-print Network

Behavioral and Environmental Conditions associated with Shark Attacks on Humans By Joshua J AND METHODS 4 2.1 DATABASE 4 2.2 SPATIAL AND TEMPORAL DISTRIBUTION OF SHARK ATTACKS 9 2.3 VICTIMS OF SHARK ATTACK 10 2.4 CHARACTERISTICS OF ATTACKING SHARKS 11 3.0 RESULTS 11 3.1 SPATIAL AND TEMPORAL DISTRIBUTION

Worm, Boris

30

Original article Non-uniformity of environmental conditions  

E-print Network

Original article Non-uniformity of environmental conditions in greenhouse lettuce production in greenhouse crops are often not uniform, this is rarely taken into account in research into the factors ou dues à l'effet de la compaction ont sans doute un rôle fondamental dans les problèmes de qualité

Paris-Sud XI, Université de

31

Leaving home ain't easy: non-local seed dispersal is only evolutionarily stable in highly unpredictable environments  

PubMed Central

It is widely understood that in the presence of asynchronous environmental variation, seeds disperse to escape disturbances, avoid crowding or colonize newly favourable habitat before a superior competitor can arrive. If seeds are dispersing for any of these reasons, it seems intuitive that they should travel far enough to reach conditions uncorrelated with their natal environment: why ‘escape in space’ only to land somewhere more or less like where they started? However, in this paper, I present a series of mathematical experiments which show that the evolutionarily stable mean dispersal distance remains well short of the spatial correlation length of the environmental variation, regardless of disturbance severity, coevolution with a superior competitor or the presence of a small fraction of seeds which travel well beyond the mean distance. Non-local dispersal arises only as part of a polymorphism that evolves when favourable conditions are fleeting. To the degree that non-local dispersal is a response to environmental variation, it appears to be a response to environmental unpredictability. PMID:20843844

Snyder, Robin E.

2011-01-01

32

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

33

Environmental Conditions for Space Flight Hardware: A Survey  

NASA Technical Reports Server (NTRS)

Interest in generalization of the physical environment experienced by NASA hardware from the natural Earth environment (on the launch pad), man-made environment on Earth (storage acceptance an d qualification testing), the launch environment, and the space environment, is ed to find commonality among our hardware in an effort to reduce cost and complexity. NASA is entering a period of increase in its number of planetary missions and it is important to understand how our qualification requirements will evolve with and track these new environments. Environmental conditions are described for NASA projects in several ways for the different periods of the mission life cycle. At the beginning, the mission manager defines survivability requirements based on the mission length, orbit, launch date, launch vehicle, and other factors . such as the use of reactor engines. Margins are then applied to these values (temperature extremes, vibration extremes, radiation tolerances, etc,) and a new set of conditions is generalized for design requirements. Mission assurance documents will then assign an additional margin for reliability, and a third set of values is provided for during testing. A fourth set of environmental condition values may evolve intermittently from heritage hardware that has been tested to a level beyond the actual mission requirement. These various sets of environment figures can make it quite confusing and difficult to capture common hardware environmental requirements. Environmental requirement information can be found in a wide variety of places. The most obvious is with the individual projects. We can easily get answers to questions about temperature extremes being used and radiation tolerance goals, but it is more difficult to map the answers to the process that created these requirements: for design, for qualification, and for actual environment with no margin applied. Not everyone assigned to a NASA project may have that kind of insight, as many have only the environmental requirement numbers needed to do their jobs but do not necessarily have a programmatic-level understanding of how all of the environmental requirements fit together.

Plante, Jeannette; Lee, Brandon

2005-01-01

34

Ecohydrology of managed ecosystems: Linking rainfall unpredictability, agronomic performance, and sustainable water use  

NASA Astrophysics Data System (ADS)

The field of ecohydrology, traditionally focusing on natural ecosystems, can offer the necessary quantitative tools to assess and compare the sustainability of agriculture across climates, soil types, crops, and irrigation strategies, including rainfall unpredictability. In particular, irrigation is one of the main strategies to enhance and stabilize agricultural productivity, but represents a cost in terms of often scarce water resources. Here, the sustainability of irrigated and rainfed agriculture is assessed by means of water productivity (defined as the ratio between yield and total supplied water), yields, water requirements, and their variability. These indicators are quantified using a probabilistic description of the soil water balance and crop development. Employing this framework, we interpret changes in water productivity as total water input is altered, in two staple crops (maize and wheat) grown under different soils, climates, and irrigation strategies. Climate change scenarios are explored by using the same approach and altering the rainfall statistics. For a given irrigation strategy, intermediate rainfall inputs leads to the highest variability in yield and irrigation water requirement - it is under these conditions that water management is most problematic. When considering the contrasting needs of limiting water requirements while ensuring adequate yields, micro-irrigation emerges as the most sustainable strategy at the field level, although consideration should be given to its profitability and long-term environmental implications.

Vico, Giulia; Porporato, Amilcare

2014-05-01

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

2010-05-01

36

Turboprop aircraft performance response to various environmental conditions  

NASA Astrophysics Data System (ADS)

This study evaluated aircraft and airfoil performance response to various environmental conditions. These conditions included clear air, warm rain, ice only, mixed phase and supercooled drops encountered during 19 separate flights. Supercooled droplets consisting of cloud, drizzle and rain sizes were the main focus of this study. Aircraft response was quantified by rates of change in aircraft rate-of-climb capability, lift and drag coefficients and lift over drag ratio. Airfoil degradation due to simulated ice shapes and drizzle ice roughness was measured in a wind tunnel for comparison. The aircraft performance parameters were compared to environmental hydrometeor parameters quantifying the environmental conditions. Results show that encounters with supercooled drizzle drops, or SCDD, resulted in maximum rates of performance degradation. These high rates of degradation forced the pilot to take evasive action within 5 minutes of entering these hazardous conditions. Encounters with supercooled cloud and rain sized drops resulted in minor to low rates of performance degradation whereas encounters with supercooled drops in low ice particle concentrations resulted in only minor rates of degradation. In addition, aircraft response to high ice particle concentrations and low liquid water, following an SCDD encounter, resulted in rapid performance recovery. The airfoil evaluations show similar results where the drizzle drop ice shape and simulated drizzle ice roughness resulted in the highest performance degradation. These evaluations also show that the most sensitive surface location is on the suction side between 6 and at least 11% of airfoil chord. Ice contaminations in this area are beyond the protective de-icing boots of most aircraft and lead to severe degradations in lift and drag characteristics. The results presented herein show a strong relationship between aircraft response and environmental parameters utilizing the larger drops in the hydrometeor distribution. The results suggest that the most severe icing is actually caused by drizzle sized drops as opposed to freezing rain. Furthermore, these results are similar to many twin-turboprop aircraft typically utilized by the commuter fleet.

Ashenden, Russell Allen

1997-10-01

37

Can environmental conditions experienced in early life influence future generations?  

PubMed Central

The consequences of early developmental conditions for performance in later life are now subjected to convergent interest from many different biological sub-disciplines. However, striking data, largely from the biomedical literature, show that environmental effects experienced even before conception can be transmissible to subsequent generations. Here, we review the growing evidence from natural systems for these cross-generational effects of early life conditions, showing that they can be generated by diverse environmental stressors, affect offspring in many ways and can be transmitted directly or indirectly by both parental lines for several generations. In doing so, we emphasize why early life might be so sensitive to the transmission of environmentally induced effects across generations. We also summarize recent theoretical advancements within the field of developmental plasticity, and discuss how parents might assemble different ‘internal’ and ‘external’ cues, even from the earliest stages of life, to instruct their investment decisions in offspring. In doing so, we provide a preliminary framework within the context of adaptive plasticity for understanding inter-generational phenomena that arise from early life conditions. PMID:24807254

Burton, Tim; Metcalfe, Neil B.

2014-01-01

38

Site fidelity in predictable and unpredictable habitats  

Microsoft Academic Search

Summary Site fidelity, the tendency to return to a previously occupied location, has been observed in numerous species belonging to at least three phyla. In this paper I develop a general model using dynamic programming to investigate conditions under which fidelity to a previously occupied territory will be advantageous. The results predict that site fidelity should be inversely related to

Paul V. Switzer

1993-01-01

39

On the unpredictability of individual quantum measurement outcomes  

E-print Network

We develop a general, non-probabilistic model of prediction which is suitable for assessing the (un)predictability of individual physical events. We use this model to provide, for the first time, a rigorous proof of the unpredictability of a class of individual quantum measurement outcomes, a well-known quantum attribute postulated or claimed for a long time. We prove that quantum indeterminism - formally modelled as value indefiniteness - is incompatible with the supposition of predictability: value indefinite observables are unpredictable. The proof makes essential use of a strengthened form of the Kochen-Specker theorem proven previously to identify value indefinite observables. As a result, quantum unpredictability, like the Kochen-Specker theorem, relies on three assumptions: compatibility with quantum mechanical predictions, non-contextuality, and the value definiteness of observables corresponding to the preparation basis of a quantum state. Finally, quantum unpredictability is used to prove that quantum randomness is "maximally incomputable", and to discuss a real model of hypercomputation whose computational power has yet to be determined. The paper ends with a further open problem.

Alastair A. Abbott; Cristian S. Calude; Karl Svozil

2014-03-11

40

Forecasting black holes in Abstract geometrical computation is highly unpredictable  

E-print Network

Forecasting black holes in Abstract geometrical computation is highly unpredictable J´er^ome Durand 2. Abstract. In Abstract geometrical computation for black hole compu- tation (MCU '04, LNCS 3354-like construction is used to provide an accumu- lation similar in effect to the black holes of the black hole model

Durand-Lose, Jérôme

41

Unpredictable Feeding Impairs Glucose Tolerance in Growing Lambs  

PubMed Central

Irregular eating is associated with insulin resistance and metabolic disease in adults but may affect young, growing children differently. We investigated the metabolic effects of unpredictable feeding in female juvenile lambs randomly assigned to receive, for six weeks, maintenance feed given twice daily in equal portions (Control Group, C; n?=?24) or the same weekly feed amount in aliquots of variable size at unpredictable times (Unpredictable Group, U; n?=?21). Intravenous glucose tolerance tests (IVGTT), insulin tolerance tests (ITT), and measurement of diurnal plasma cortisol concentrations were performed pre and post the dietary intervention. Groups were compared using t test and RM ANOVA. Weight gain was similar in both groups (C 18±2%; U 16±2% of initial body weight). Glucose area under the curve (AUC) was unchanged in C (AUC pre 818±34, post 801±33 mmol.min.l?1), but increased by 20% in U (pre 830±25, post 1010±19 mmol.min.l?1; p<0.0001), with an inadequate insulin response to glucose load (log(AUC insulin first 40 minutes) post intervention C 1.49±0.04 vs U 1.36±0.04 ng.min.ml?1; p?=?0.03). Insulin tolerance and diurnal variation of plasma cortisol concentrations were not different between groups. Unpredictable feeding impairs insulin response to glucose in growing lambs despite high quality food and normal weight gain. Irregular eating warrants investigation as a potentially remediable risk factor for disordered glucose metabolism. PMID:23613779

Jaquiery, Anne L.; Oliver, Mark H.; Landon-Lane, Nina; Matthews, Samuel J.; Harding, Jane E.; Bloomfield, Frank H.

2013-01-01

42

ELECTROCORTICAL ACTIVITY PRIOR TO UNPREDICTABLE STIMULI IN MEDITATORS AND NONMEDITATORS  

E-print Network

ELECTROCORTICAL ACTIVITY PRIOR TO UNPREDICTABLE STIMULI IN MEDITATORS AND NONMEDITATORS Dean I. Radin, PhD,1# Cassandra Vieten, PhD,1 Leena Michel,1 and Arnaud Delorme, PhD2 Advanced meditators meditators and eight matched controls by measuring 32 channels of EEG before, during, and after exposure

43

Regularizing Unpredictable Variation: The Roles of Adult and Child Learners  

E-print Network

Regularizing Unpredictable Variation: The Roles of Adult and Child Learners in Language Formation affects its learning. In the second experiment we compare adult and child learners exposed and Change Carla L. Hudson Kam Department of Psychology University of California, Berkeley Elissa L. Newport

DeAngelis, Gregory

44

Findings Brief: Unpredictable Demand and Low-Volume Hospitals.  

National Technical Information Service (NTIS)

This Findings Brief assesses the degree to which the annual number of patient discharges varies from year to year for low volume hospitals. To the extent that demand for inpatient services is unpredictable, it is hard for administrators to set budget and ...

K. Dalton, M. Holmes, R. Slifkin

2003-01-01

45

Handling unpredicted motion in industrial robot workcells using sensor networks  

Microsoft Academic Search

Purpose – Aims to show how sensor networks can be used to effectively allow industrial robots to handle unpredicted movements within their workcells. Design\\/methodology\\/approach – Presents the concept of using sensor networks, using off-the-shelf technologies, to sense in real time movements within the workcell, and to feed this information, in real time, to the industrial robot controller, to allow adaptation

Ian Walker; Adam Hoover; Yanfei Liu

2006-01-01

46

Long-term colonic hypersensitivity in adult rats induced by neonatal unpredictable vs predictable shock  

PubMed Central

Our goal was to examine the relationship between early life trauma and the development of visceral hypersensitivity in later life in irritable bowel syndrome (IBS). Rat pups underwent neonatal conditioning: (i) paired odour-shock, where odour is a predictable shock signal, (ii) unpaired odour-shock, where odour is an unpredictable shock signal or (iii) control odour-only with odour presentations and handling without shock. At maturity, colorectal sensitivity was measured as a visceromotor behavioural response. In adulthood, colorectal distension (CRD) induced a pressure-dependent increase in the number of abdominal muscle contractions all three experimental groups. However, compared to animals that had received control odour-only presentations in infancy, there was an attenuated response to CRD in animals previously exposed to neonatal predictable shock pups and an exaggerated response in the animals previously exposed to neonatal unpredictable shock. Adult responses to CRD were altered by infant experience with shock trauma. However, depending on the context of that early life trauma, there are major differences between the long-term effects of that early life trauma on colonic sensitivity compared to controls. These results strengthen the link between early life trauma and adult IBS, and suggest that unpredictable trauma is a critical factor for later life disorders. PMID:17727395

TYLER, K.; MORICEAU, S.; SULLIVAN, R. M.; MEERVELD, B. GREENWOOD-VAN

2007-01-01

47

K, U, and Th behavior in Martian environmental conditions  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

48

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

2013-03-01

49

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

50

Evaluating Microbial Indicators of Environmental Condition in Oregon Rivers  

NASA Astrophysics Data System (ADS)

Traditional bacterial indicators used in public health to assess water quality and the Biolog® system were evaluated to compare their response to biological, chemical, and physical habitat indicators of stream condition both within the state of Oregon and among ecoregion aggregates (Coast Range, Willamette Valley, Cascades, and eastern Oregon). Forty-three randomly selected Oregon river sites were sampled during the summer in 1997 and 1998. The public health indicators included heterotrophic plate counts (HPC), total coliforms (TC), fecal coliforms (FC) and Escherichia coli (EC). Statewide, HPC correlated strongly with physical habitat (elevation, riparian complexity, % canopy presence, and indices of agriculture, pavement, road, pasture, and total disturbance) and chemistry (pH, dissolved O2, specific conductance, acid-neutralizing capacity, dissolved organic carbon, total N, total P, SiO2, and SO4). FC and EC were significantly correlated generally with the river chemistry indicators. TC bacteria significantly correlated with riparian complexity, road disturbance, dissolved O2, and SiO2 and FC. Analyzing the sites by ecoregion, eastern Oregon was characterized by high HPC, FC, EC, nutrient loads, and indices of human disturbance, whereas the Cascades ecoregion had correspondingly low counts of these indicators. The Coast Range and Willamette Valley presented inconsistent indicator patterns that are more difficult to characterize. Attempts to distinguish between ecoregions with the Biolog system were not successful, nor did a statistical pattern emerge between the first five principle components and the other environmental indicators. Our research suggests that some traditional public health microbial indicators may be useful in measuring the environmental condition of lotic systems.

Pennington, Alan T.; Harding, Anna K.; Hendricks, Charles W.; Campbell, Heidi M. K.

2001-12-01

51

CLOUD-TO-GROUND LIGHTNING POLARITY AND ENVIRONMENTAL CONDITIONS OVER THE CENTRAL UNITED STATES  

E-print Network

THESIS CLOUD-TO-GROUND LIGHTNING POLARITY AND ENVIRONMENTAL CONDITIONS OVER THE CENTRAL UNITED SUPERVISION BY CHRISTINA KALB ENTITLED CLOUD-TO-GROUND LIGHTNING POLARITY AND ENVIRONMENTAL CONDITIONS OVER __________________________________________ Richard H. Johnson, Head #12;iii ABSTRACT CLOUD-TO-GROUND LIGHTNING POLARITY AND ENVIRONMENTAL CONDITIONS

Rutledge, Steven

52

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

53

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

Microsoft Academic Search

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

Christian Grillon; Anja Schmitz

2012-01-01

54

Biodegradation of a Light NAPL under Varying Soil Environmental Conditions  

NASA Astrophysics Data System (ADS)

To see the impact of different soil environmental conditions on LNAPL biodegradation, a series of batch, microcosm, column and 2-D tank experiments under controlled conditions have been planned. Microcosms along with batch experiments have been designed for five different moisture contents ranging from residual to saturated, and under varying temperature condition. The batches are being used for two saturated soils containing toluene. For the unsaturated cases, fifteen microcosms are designed to mimic natural conditions more closely. The microcosms consist of a transparent outer column and an air permeable, but watertight, inner tube comprised of toluene phobic material. The space between the outer column and the inner porous tube is filled with a soil having a particular moisture content with a known amount of toluene. The inner porous tube is filled with air at atmospheric pressure, providing sufficient oxygen for the degradation of considered light NAPL. A special sampling mechanism has been fabricated to enable airtight soil sampling. Four columns have been designed for studying the impact of water table fluctuation on the LNAPL fate and transport in variably-saturated soil. Water table in two columns will be static and remaining two will be subjected to a fluctuation. Finally a 2-D tank setup, made of a steel box and a glass cover, has been refurbished for bioremediation process of LNAPL from start to finish. The main body is constructed of one piece of 1.5 mm thick stainless steel formed into a box with inner dimensions of 200cm-long x 94cm-high x 4cm-deep. The front cover is made of glass wall having 19-mm thickness. The soil is going to be packed between the two walls. The groundwater will be flowing horizontally from left to right and the water table level in the tank will be controlled by two end chambers. The chambers are separated from the soil by a fine meshed stainless steel sheet. The spatial and the temporal distributions of the LNAPL and its concentration in water and air phase along with soil moisture content will be determined experimentally and also numerically. The results of these different scale experiments (microcosm to 2-D tank) can be used for upscaling the process of LNAPL degradation in vadose zone and will be relevant to fields such as bioremediation.

Yadav, B. K.; Hassanizadeh, S. M.; Kleingeld, P. J.

2009-12-01

55

Surface monitoring measurements of materials on environmental change conditions  

NASA Astrophysics Data System (ADS)

Climate Change is one of the most critical global challenges of our time and the burdened cultural heritage of Europe is particularly vulnerable to be left unprotected. Climate for Culture2 project exploits the damage impact of climate change on cultural heritage at regional scale. In this paper the progress of the study with in situ measurements and investigations at cultural heritage sites throughout Europe combined with laboratory simulations is described. Cultural works of art are susceptible to deterioration with environmental changes causing imperceptibly slow but steady accumulation of damaging effects directly impacted on structural integrity. Laser holographic interference method is employed to provide remote non destructive field-wise detection of the structural differences occurred as climate responses. The first results from climate simulation of South East Europe (Crete) are presented. A full study in regards to the four climate regions of Europe is foreseen to provide values for development of a precise and integrated model of thermographic building simulations for evaluation of impact of climate change. Development of a third generation user interface software optimised portable metrology system (DHSPI II) is designed to record in custom intervals the surface of materials witnessing reactions under simulated climatic conditions both onfield and in laboratory. The climate conditions refer to real data-loggers readings representing characteristic historical building in selected climate zones. New generation impact sensors termed Glass Sensors and Free Water Sensors are employed in the monitoring procedure to cross-correlate climate data with deformation data. In this paper results from the combined methodology are additionally presented.

Tornari, Vivi; Bernikola, Eirini; Bellendorf, Paul; Bertolin, Chiara; Camuffo, Dario; Kotova, Lola; Jacobs, Daniela; Zarnic, Roko; Rajcic, Vlatka; Leissner, Johanna

2013-05-01

56

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

57

Impact of Environmental Conditions on the Survival of Cryptosporidium and Giardia on Environmental Surfaces  

PubMed Central

The objective of this study was to find out the impact of environmental conditions on the survival of intestinal parasites on environmental surfaces commonly implicated in the transmission of these parasites. The study was performed by incubating Cryptosporidium and Giardia (oo)cysts on environmentally relevant surfaces such as brushed stainless steel, formica, ceramic, fabric, and skin. Parallel experiments were conducted using clean and soiled coupons incubated under three temperatures. The die-off coefficient rates (K) were calculated using first-order exponential formula. For both parasites, the fastest die-off was recorded on fabric, followed by ceramic, formica, skin, and steel. Die-off rates were directly correlated to the incubation temperatures and surface porosity. The presence of organic matter enhanced the survivability of the resting stages of test parasites. The decay rates calculated in this study can be used in models for public health decision-making process and highlights the mitigation role of hand hygiene agents in their prevention and control. PMID:25045350

Alum, Absar; Absar, Isra M.; Asaad, Hamas; Rubino, Joseph R.; Ijaz, M. Khalid

2014-01-01

58

Quorum-regulated biofilms enhance the development of conditionally viable, environmental Vibrio cholerae  

E-print Network

Quorum-regulated biofilms enhance the development of conditionally viable, environmental Vibrio that this process involves biofilm formation that is dependent on quorum sens- ing, a regulatory response and biofilm formation displayed altered CVEC formation in environmental waterfollowingintestinalinfections

Mekalanos, John

59

Effects of Environmental Conditions on an Urban Wetland's Methane Fluxes  

NASA Astrophysics Data System (ADS)

Methane emissions from wetlands are the largest natural source of uncertainty in the global methane (CH4) budget. Wetlands are highly productive ecosystems with a large carbon sequestration potential. While wetlands are a net sink for carbon dioxide, they also release methane, a potent greenhouse gas. To effectively develop wetland management techniques, it is important to properly calculate the carbon budget of wetlands by understand the driving factors of methane fluxes. We constructed an eddy flux covariance system in the Olentangy River Wetland Research Park, a series of created and restored wetland in Columbus Ohio. Through the use of high frequency open path infrared gas analyzer (IRGA) sensors, we have continuously monitored the methane fluxes associated with the wetland since May 2011. To account for the heterogeneous landscape surrounding the tower, a footprint analysis was used to isolate data originating from within the wetland. Continuous measurements of the meteorological and environmental conditions at the wetlands coinciding with the flux measurements allow the interactions between methane fluxes and the climate and ecological forcing to be studied. The wintertime daily cycle of methane peaks around midday indicating a typical diurnal pattern in cold months. In the summer, the peak shifts to earlier in the day and also includes a daily peak occurring at approximately 10 AM. We believe this peak is associated with the onset of photosynthesis in Typha latifolia flushing methane from the plant's air filled tissue. Correlations with methane fluxes include latent heat flux, soil temperature, and incoming radiation. The connection to radiation may be further evidence of plant activity as a driver of methane fluxes. Higher methane fluxes corresponding with higher soil temperature indicates that warmer days stimulate the methanogenic consortium. Further analysis will focus on separating the methane fluxes into emissions from different terrain types within the wetland.

Naor Azrieli, L.; Morin, T. H.; Bohrer, G.; Schafer, K. V.; Brooker, M.; Mitsch, W. J.

2013-12-01

60

Privatizing conditions of production: trade agreements as neoliberal environmental governance  

Microsoft Academic Search

Recent multilateral trade agreements are among the major manifestations of neoliberalism. They are also emerging as some of the most important sites of environmental governance in the 21st century. I argue here that these trade agreements, particularly the sweeping new protections they provide for investors, are redefining property rights and environmental governance in fundamental ways. I suggest that in addition

James McCarthy

2004-01-01

61

INTEGRATED ASSESSMENTS OF THE ENVIRONMENTAL CONDITION OF THE CHESAPEAKE BAY  

EPA Science Inventory

The Chesapeake Bay, the Nation's largest estuary, has experienced environmental degradation due to nutrient enrichment, contamination, loss of habitat, and over-harvesting of living resources. Resource managers need information on the extent of degradation to formulate restoratio...

62

Use of prey hotspots by an avian predator: purposeful unpredictability?  

PubMed

The use of space by predators in relation to their prey is a poorly understood aspect of predator-prey interactions. Classic theory suggests that predators should focus their efforts on areas of abundant prey, that is, prey hotspots, whereas game-theoretical models of predator and prey movement suggest that the distribution of predators should match that of their prey's resources. If, however, prey are spatially anchored to one location and these prey have particularly strong antipredator responses that make them difficult to capture with frequent attacks, then predators may be forced to adopt alternative movement strategies to hunt behaviorally responsive prey. We examined the movement patterns of bird-eating sharp-shinned hawks (Accipiter striatus) in an attempt to shed light on hotspot use by predators. Our results suggest that these hawks do not focus on prey hotspots such as bird feeders but instead maintain much spatial and temporal unpredictability in their movements. Hawks seldom revisited the same area, and the few frequently used areas were revisited in a manner consistent with unpredictable returns, giving prey little additional information about risk. PMID:17211809

Roth, Timothy C; Lima, Steven L

2007-02-01

63

[Melanin pigments of fungi under extreme environmental conditions (review)].  

PubMed

This review is dedicated to the research on the functions of melanin pigments in fungi. The participation of melanin pigments in protection from environmental factors is considered. Data on the biosynthetic pathways and types of melanin pigments in fungi are presented. PMID:25272728

Gessler, N N; Egorova, A S; Belozerskaia, T A

2014-01-01

64

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

65

EFFECT OF ENVIRONMENTAL CONDITIONS ON PRODUCTIVE AND PHYSIOLOGICAL RESPONSES IN GROWING RABBITS  

Microsoft Academic Search

Environmental conditions are important for the welf are of intensively-reared rabbits. The presence inside the cage of a piece of wood represents a for m of environmental enrichment, but also an alternative type of feeding. A trial was carried ou t to study the effect of lighting and type of feedi ng on the productive performance, bone conditions and pla

66

Chronic unpredictable mild stress combined with a high-fat diets aggravates atherosclerosis in rats  

PubMed Central

Background Depression and high-fat diet are both known as independent risk factors for atherosclerosis and other cardiovascular diseases, suggesting the interaction of psychological and physiological factors in the development of these diseases. The liver is a crucial organ that facilitate lipid metabolism especially in reverse cholesterol transport (RCT), while according to the theory of Traditional Chinese Medicine, depression as a kind of psychological stress has an influence on hepatic function. So there seem to be some links between depression and lipid metabolic disorders. Methods To investigate these links, we separately treated rats with chronic unpredictable mild stress (CMS) and/or a high-fat diet (HD) to evaluate the development of atherosclerosis and the expression of hepatic ABCG8, ABCG5, SR-BI, CYP7A1, LXR?, and LCAT which were associated with reverse cholesterol transport. Results This study provided evidence that high-fat diet greatly decreased these genes expression related to RCT while chronic stress alone tended to promote RCT. Chronic unpredictable mild stress combined with a high-fat diet attenuated RCT and aggravated atherogenesis. Conclusions These observations suggested that chronic psychological stress alone is virtually propitious to lipid metabolism, however when under a condition of high-fat diet, it deteriorated atherosclerotic plague and did harm to RCT. PMID:24885743

2014-01-01

67

AGE AND ENVIRONMENTAL CONDITIONS AFFECT RECRUITMENT IN GREATER SNOW GEESE  

Microsoft Academic Search

Recruitment is an important determinant of fitness and population growth rates, but few studies have examined the effect of environmental stochasticity on this life history trait. Furthermore, most studies have been unable to separate the influence of juvenile survival and age-specific breeding proportions on recruitment. We used a recently developed approach, based on capture-mark-recapture methods, in which local recruitment is

Eric T. Reed; Gilles Gauthier; Roger Pradel; Jean-Dominique Lebreton

2003-01-01

68

Equine influenza: a review of an unpredictable virus.  

PubMed

This review discusses some of the challenges still faced in the control of equine influenza virus H3N8 infection. A widespread outbreak of equine influenza in the United Kingdom during 2003 in vaccinated Thoroughbred racehorses challenged the current dogma on vaccine strain selection. Furthermore, several new developments in the first decade of the 21st century, including transmission to and establishment in dogs, a presumed influenza-associated encephalopathy in horses and an outbreak of equine influenza in Australia, serve as a reminder of the unpredictable nature of influenza viruses. The application of newly available techniques described in this review may further elucidate some of the viral factors that underlie recent events and provide the tools to better evaluate when vaccine strains should be updated. PMID:20685140

Daly, Janet M; MacRae, Shona; Newton, J Richard; Wattrang, Eva; Elton, Debra M

2011-07-01

69

The effects of adverse environmental conditions on workload  

E-print Network

in apparent good physical condition and volun- teered to participate. Each subject was requested to wear summer clo- thing to provide some uniformity for evaluating the effects of the en- vironmentt. Near visual acuity was a subject characteristic... in apparent good physical condition and volun- teered to participate. Each subject was requested to wear summer clo- thing to provide some uniformity for evaluating the effects of the en- vironmentt. Near visual acuity was a subject characteristic...

Martin, Ann Elizabeth

2012-06-07

70

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

2012-11-01

71

EFFECTS OF ENVIRONMENTAL CONDITIONS ON ISOPRENE EMISSION FROM LIVE OAK  

EPA Science Inventory

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 emission increases as the ambie...

72

Project 198740100 Assessment of Smolt Condition: Biological and Environmental Interactions  

E-print Network

for three water quality variables, which include temperature and changes in temperature, and average monthly-river survival/estuary * * * * * temperature * * precocity/residualism--control by growth and temperature, higher at production facilities ­ density, temperature, flow, water quality, feed enhancement, release condition

73

West Chesapeake Basin: Environmental Assessment of Stream Conditions.  

National Technical Information Service (NTIS)

The primary purpose of this report is to describe existing aquatic resource conditions in first, second, and third order non-tidal streams of the West Chesapeake basin during 1997. This document also serves as an update to a previous Maryland Department o...

D. T. Ostrowski, C. J. Millard, P. F. Kazyak, D. M. Boward

1999-01-01

74

Pocomoke River Basin. Environmental Assessment of Stream Conditions.  

National Technical Information Service (NTIS)

This report describes existing aquatic resource conditions during 1997 in first, second, and third-order non-tidal streams in the Pocomoke River basin in Maryland. The report also begins to assess water quality and habitat problems in the basin, as well a...

A. Lenert, C. J. Millard, P. F. Kazyak, D. M. Boward

1999-01-01

75

The community conditioning hypothesis and its application to environmental toxicology  

Microsoft Academic Search

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

Robin A. Matthews; Wayne G. Landis; Geoffrey B. Matthews

1996-01-01

76

Environmental conditions and fen vegetation in three lowland mires  

Microsoft Academic Search

The abiotic conditions and fen vegetation in three lowland mires were analysed. Two of these mires are in the Netherlands. They have deteriorated considerably as a result of human pressure. One mire complex is in Poland. Its hydrology is almost undisturbed. The variation in the water composition in the fens was associated with the variation in the amount of regional

M. C. Bootsma; M. J. Wassen

1996-01-01

77

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

78

Extinction conditions for isolated populations affected by environmental stochasticity.  

PubMed

We determine the critical patch size below which extinction occurs for populations living in one-dimensional habitats surrounded by completely hostile environments in the presence of environmental fluctuations. The population dynamics is reformulated in terms of a stochastic reaction-diffusion equation and is reduced to a deterministic equation that incorporates the systematic contributions of the noise. We obtain bifurcation diagrams and relations for the mean population density at the stationary state, the critical patch size, and the mean number of individuals in the habitat. The effect of the noise differs, depending on whether it affects the net growth rate or the intraspecific competition term. Fluctuations in the net growth rate decrease the critical patch size, whereas fluctuations in the competition term do not change the critical patch size. We compare our analytical results with numerical solutions of the stochastic partial differential equations and show that our procedure proves useful in dealing with reaction-diffusion equations with multiplicative noise. PMID:20219497

Méndez, Vicenç; Llopis, Isaac; Campos, Daniel; Horsthemke, Werner

2010-06-01

79

Vibration-based structural health monitoring using adaptive statistical method under varying environmental condition  

NASA Astrophysics Data System (ADS)

It is well known that the dynamic properties of a structure such as natural frequencies depend not only on damage but also on environmental condition (e.g., temperature). The variation in dynamic characteristics of a structure due to environmental condition may mask damage of the structure. Without taking the change of environmental condition into account, false-positive or false-negative damage diagnosis may occur so that structural health monitoring becomes unreliable. In order to address this problem, an approach to construct a regression model based on structural responses considering environmental factors has been usually used by many researchers. The key to success of this approach is the formulation between the input and output variables of the regression model to take into account the environmental variations. However, it is quite challenging to determine proper environmental variables and measurement locations in advance for fully representing the relationship between the structural responses and the environmental variations. One alternative (i.e., novelty detection) is to remove the variations caused by environmental factors from the structural responses by using multivariate statistical analysis (e.g., principal component analysis (PCA), factor analysis, etc.). The success of this method is deeply depending on the accuracy of the description of normal condition. Generally, there is no prior information on normal condition during data acquisition, so that the normal condition is determined by subjective perspective with human-intervention. The proposed method is a novel adaptive multivariate statistical analysis for monitoring of structural damage detection under environmental change. One advantage of this method is the ability of a generative learning to capture the intrinsic characteristics of the normal condition. The proposed method is tested on numerically simulated data for a range of noise in measurement under environmental variation. A comparative study with conventional methods (i.e., fixed reference scheme) demonstrates the superior performance of the proposed method for structural damage detection.

Jin, Seung-Seop; Jung, Hyung-Jo

2014-03-01

80

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

81

Community health nursing practices in contexts of poverty, uncertainty and unpredictability: a systematization of personal experiences.  

PubMed

Several years of professional nursing practices, while living in the poorest neighbourhoods in the outlying areas of Brazil's Amazon region, have led the author to develop a better understanding of marginalized populations. Providing care to people with leprosy and sex workers in riverside communities has taken place in conditions of uncertainty, insecurity, unpredictability and institutional violence. The question raised is how we can develop community health nursing practices in this context. A systematization of personal experiences based on popular education is used and analyzed as a way of learning by obtaining scientific knowledge through critical analysis of field practices. Ties of solidarity and belonging developed in informal, mutual-help action groups are promising avenues for research and the development of knowledge in health promotion, prevention and community care and a necessary contribution to national public health programmers. PMID:17934576

Laperrière, Hélène

2007-01-01

82

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...

83

A Four-day Workweek: a Policy for Improving Employment and Environmental Conditions in Europe  

E-print Network

Can working less lead to a healthier economy and better environmental conditions? Which factors should be taken into consideration when forming an answer to this question? In this article Nicholas Ashford and Giorgos Kallis ...

Ashford, Nicholas A.

84

Water Retention of Extremophiles and Martian Soil Simulants Under Close to Martian Environmental Conditions  

NASA Astrophysics Data System (ADS)

We report data about interaction of moisture with soil simulants and extremophiles under Martian environmental conditions contributing on atmosphere/surface modelling and on effects determining the water inventory of the upper soil layer of Mars.

Jänchen, J.; Bauermeister, A.; Feyh, N.; deVera, J.-P.

2012-05-01

85

Neglected Buildings, Damaged Health: A "Snapshot" of New York City Public School Environmental Conditions.  

ERIC Educational Resources Information Center

Survey results are presented from 65 parents, students over 12 years, teachers, and other school employees using 39 different schools about environmental conditions in New York City public schools. It shows the results of years of neglect of infrastructure for children and reveals disturbing new information about the environmental health of school…

Advocates for Children of New York, Inc., Long Island City.

86

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

87

Rift Valley Fever Outbreaks in Mauritania and Related Environmental Conditions  

PubMed Central

Four large outbreaks of Rift Valley Fever (RVF) occurred in Mauritania in 1998, 2003, 2010 and 2012 which caused lots of animal and several human deaths. We investigated rainfall and vegetation conditions that might have impacted on RVF transmission over the affected regions. Our results corroborate that RVF transmission generally occurs during the months of September and October in Mauritania, similarly to Senegal. The four outbreaks were preceded by a rainless period lasting at least a week followed by heavy precipitation that took place during the second half of the rainy season. First human infections were generally reported three to five weeks later. By bridging the gap between meteorological forecasting centers and veterinary services, an early warning system might be developed in Senegal and Mauritania to warn decision makers and health services about the upcoming RVF risk. PMID:24413703

Caminade, Cyril; Ndione, Jacques A.; Diallo, Mawlouth; MacLeod, Dave A.; Faye, Ousmane; Ba, Yamar; Dia, Ibrahima; Morse, Andrew P.

2014-01-01

88

Neurochemical and behavioral effects of chronic unpredictable stress.  

PubMed

Chronic stress can influence behaviors associated with medial prefrontal cortex (mPFC) function, such as cognition and emotion regulation. Dopamine in the mPFC is responsive to stress and modulates its behavioral effects. The current study tested whether exposure to 10 days of chronic unpredictable stress (CUS) altered the effects of acute elevation stress on dopamine release in the mPFC and on spatial recognition memory. Male rats previously exposed to CUS or nonstressed controls were tested behaviorally, underwent microdialysis to assess mPFC dopamine levels or underwent blood sampling for corticosterone analysis. Dopamine in the mPFC significantly increased in both groups during acute elevation stress compared with baseline levels, but the level was attenuated in CUS rats compared with controls. Control rats exposed to elevation stress immediately before the T-maze test showed impaired performance, whereas CUS rats did not. No group differences were observed in general motor activity or plasma corticosterone levels following elevation stress. The present results indicate that prior exposure to this CUS procedure reduced dopamine release in the mPFC during acute elevation stress and prevented the impairment of performance on a spatial recognition test following an acute stressor. These findings may contribute to an understanding of the complex behavioral consequences of stress. PMID:25003946

Matuszewich, Leslie; McFadden, Lisa M; Friedman, Ross D; Frye, Cheryl A

2014-09-01

89

Coping with Unpredictability: Dopaminergic and Neurotrophic Responses to Omission of Expected Reward in Atlantic Salmon (Salmo salar L.)  

PubMed Central

Comparative studies are imperative for understanding the evolution of adaptive neurobiological processes such as neural plasticity, cognition, and emotion. Previously we have reported that prolonged omission of expected rewards (OER, or ‘frustrative nonreward’) causes increased aggression in Atlantic salmon (Salmo salar). Here we report changes in brain monoaminergic activity and relative abundance of brain derived neurotrophic factor (BDNF) and dopamine receptor mRNA transcripts in the same paradigm. Groups of fish were initially conditioned to associate a flashing light with feeding. Subsequently, the expected food reward was delayed for 30 minutes during two out of three meals per day in the OER treatment, while the previously established routine was maintained in control groups. After 8 days there was no effect of OER on baseline brain stem serotonin (5-HT) or dopamine (DA) activity. Subsequent exposure to acute confinement stress led to increased plasma cortisol and elevated turnover of brain stem DA and 5-HT in all animals. The DA response was potentiated and DA receptor 1 (D1) mRNA abundance was reduced in the OER-exposed fish, indicating a sensitization of the DA system. In addition OER suppressed abundance of BDNF in the telencephalon of non-stressed fish. Regardless of OER treatment, a strong positive correlation between BDNF and D1 mRNA abundance was seen in non-stressed fish. This correlation was disrupted by acute stress, and replaced by a negative correlation between BDNF abundance and plasma cortisol concentration. These observations indicate a conserved link between DA, neurotrophin regulation, and corticosteroid-signaling pathways. The results also emphasize how fish models can be important tools in the study of neural plasticity and responsiveness to environmental unpredictability. PMID:24465595

Vindas, Marco A.; S?rensen, Christina; Johansen, Ida B.; Folkedal, Ole; Hoglund, Erik; Khan, Uniza W.; Stien, Lars H.; Kristiansen, Tore S.; Braastad, Bjarne O.; ?verli, ?yvind

2014-01-01

90

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. PMID:23847501

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

2013-01-01

91

Flexible DCP interface. [signal conditioning system for use with Kansas environmental sensors  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. A user of an ERTS data collection system must supply the sensors and signal conditioning interface. The electronic interface must be compatible with the NASA-furnished data collection platform (DCP). A universal signal conditioning system for use with a wide range of environmental sensors is described. The interface is environmentally and electronically compatible with the DCP and has operated satisfactorily for a complete winter wheat growing season in Kansas.

Kanemasu, E. T. (principal investigator); Schimmelpfenning, H.

1974-01-01

92

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

93

Eye Movements When Observing Predictable and Unpredictable Actions Gerben Rotman,1  

E-print Network

, they implement covert action plans that, in real time, match the action plans executed by the actor (for reviewEye Movements When Observing Predictable and Unpredictable Actions Gerben Rotman,1 Nikolaus F movements when observing predictable and unpredictable actions. J Neurophysiol 96: 1358­1369, 2006. First

Flanagan, Randy

94

Migration of birds as an indicator of broad-scale environmental condition.  

PubMed

The migration of Neotropical birds may provide a robust measure of changing environmental condition along the migratory route. I review previous work on assessing broad-scale stopover quality in the eastern United States and discuss how future research can aid regional environmental assessment. Scientists can quantify how environmental changes affect the migratory system, and then monitor for those effects on migrant abundance from year to year. The cyclical nature of migration provides a constant re-evaluation of habitat quality and spatial distribution by migrant birds. Avian monitoring programs can detect changes in migrant abundance. Migrating birds may thus provide a living sensor of environmental change, enabling broad-scale environmental assessments to detect and address habitat degradation early on, allowing local managers to prioritize restoration efforts accordingly. Understanding the environmental factors driving stopover selection, and how birds move between stopovers during migration, is an important first step. PMID:15141446

Tankersley, Roger D

2004-06-01

95

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

96

Molten-salt thermal energy storage in thermoclines under different environmental boundary conditions  

Microsoft Academic Search

Operation during the charge and discharge cycles of molten-salt thermoclines used for solar thermal energy storage depends strongly on the environmental boundary conditions to which the tanks are exposed. A comprehensive model which accounts for thermal transport in the molten-salt heat transfer fluid and the filler material in the tank is developed for exploring the effects of boundary conditions on

Zhen Yang; Suresh V. Garimella

2010-01-01

97

Effect of environmental conditions on the properties of fresh and hardened concrete  

Microsoft Academic Search

The effect of varying environmental conditions, at the time of casting on the properties of fresh and hardened concrete was evaluated. The influence of air temperature, wind velocity, and relative humidity on plastic shrinkage, compressive strength, pulse velocity and pore structure of concrete was investigated. Results indicate that exposure conditions at the time of casting significantly affect plastic shrinkage of

Abdullah A Almusallam

2001-01-01

98

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

2009-01-01

99

Multiscale Effects of Management, Environmental Conditions, and Land Use on Nitrate Leaching in Dairy Farms  

Microsoft Academic Search

Nitrate leaching in intensive grassland- and silage maize-based dairy farming systems on sandy soil is a main environmental concern. Here, statistical relationships are presented between management practices and environmental conditions and nitrate concentration in shallow groundwater (0.8 m depth) at farm, field, and point scales in the Netherlands, based on data collected in a participatory approach over a 7-yr period

J. Oenema; S. L. G. E. Burgers; J. Verloop; A. Hooijboer; L. Boumans; Berge ten H. F. M

2010-01-01

100

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. PMID:22748829

Kiyatkin, Eugene A.; Sharma, Hari S.

2013-01-01

101

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

102

Patinas developed in environmental burial conditions: the Neolithic steles of Reguers de Seró (Lleida, Spain)  

Microsoft Academic Search

Background, aim and scope  Weathering patinas in rocks are the result of interaction processes between rock surfaces and atmosphere, biosphere and soil.\\u000a Therefore, their textural and mineral composition is strongly related to environmental and bioactivity conditions. Whereas\\u000a the development of weathering patinas in atmospheric conditions is well documented (e.g. typical Mediterranean patina), only\\u000a very few studies focus on their formation in

Maite Garcia-Valles; Meritxell Aulinas; Joan B. López-Melción; Andreu Moya-Garra

2010-01-01

103

Environmental heterogeneity influences the reliability of secondary sexual traits as condition indicators.  

PubMed

Numerous studies have shown positive associations between ornaments and condition, as predicted by indicator models of sexual selection. However, this idea is continuously challenged by opposite results, which reveal our lack of full understanding of how sexual selection works. Environmental heterogeneity may explain such inconsistencies, but valid field tests of this idea are currently lacking. We first analysed the relationship between condition and ornament expression from nine populations over 7 years in a wild bird, the red grouse Lagopus lagopus scoticus. We then manipulated male aggressiveness at the population level by means of testosterone implants in a replicated field experiment. We found that the relationship between condition and ornamentation varied greatly between environments and became stronger when environmental conditions (ECs) were worse or when aggressiveness in the population was experimentally increased. Some ornaments may therefore reliably advertise a better condition only in adverse ECs. Considering environmental heterogeneity can help reconcile conflicting findings regarding the reliability of ornaments as indicators of condition and will help our understanding of sexual selection processes. PMID:22022806

Vergara, Pablo; Martinez-Padilla, J; Mougeot, F; Leckie, F; Redpath, S M

2012-01-01

104

The Universal Arrow of Time V-VI: (Part V) Unpredictable dynamics (Part VI) Future of artificial intelligence - Art, not Science: Practical Application of Unpredictable Systems  

E-print Network

The paper consists of the two independent papers:(Part V) We see that exact equations of quantum and classical mechanics describe ideal dynamics which is reversible and leads to Poincare's returns. Real equations of physics describing observable dynamics, for example, hydrodynamic equations of viscous fluid, are irreversible and exclude Poincare's returns to the initial state. Besides, these equations describe systems in terms of macroparameters or phase distribution functions of microparameters. For many systems introduction of macroparameters that allow exhaustive describing of dynamics of the system is impossible. Their dynamics becomes unpredictable in principle, sometimes even unpredictable by the probabilistic way. We will refer to dynamics describing such system as unpredictable dynamics. Dynamics of unpredictable systems is not described and not predicted by scientific methods. Thus, the science itself puts boundaries for its applicability. But such systems can intuitively "understand itself" and "predict" the behavior "of its own" or even "communicate with each other" at intuitive level. (Part VI) Perspective of the future of artificial intellect (AI) is considered. It is shown that AI development in the future will be closer rather to art than to science. Complex dissipative systems whose behavior cannot be understood completely in principle will be the basis of AI. Nevertheless, it will not be a barrier for their practical use.

Oleg Kupervasser

2011-07-07

105

Relation between Respiratory Sinus Arrythymia and Startle Response during Predictable and Unpredictable Threat  

PubMed Central

Research suggests that lower respiratory sinus arrhythmia (RSA) is associated with greater aversive responding. One physiological indicator of aversive responding is startle potentiation. While a few studies have demonstrated an inverse association between RSA and startle potentiation, no study to date has distinguished whether this relation is similar for predictable versus unpredictable aversive stimuli. This is an important distinction, given that degree of predictability has been shown to be an important determinant of aversive responding. The present study examined whether resting RSA was associated with startle eye blink responding during predictable and unpredictable threat of electric shock. Resting RSA was collected during a 6-minute seated baseline phase at the beginning of the experimental session. Participants then completed a computerized startle task in which predictable and unpredictable shocks were administered. Results indicated that lower resting RSA was associated with greater startle potentiation during unpredictable threat, but not during predictable threat. These findings are consistent with a growing body of literature suggesting that individual differences in RSA are associated with aversive responding, and extend previous work by suggesting that RSA may be more robustly associated with a heightened sensitivity to unpredictable threat. This pattern of results may have implications for the understanding of pathological anxiety given that individuals with anxiety disorders typically exhibit low RSA and heightened responding during unpredictable threat. PMID:23788825

Gorka, Stephanie M.; Nelson, Brady D.; Sarapas, Casey; Campbell, Miranda; Lewis, Gregory F.; Bishop, Jeffery R.; Porges, Stephen W.; Shankman, Stewart A.

2013-01-01

106

Applications of remote sensing for the evaluation of Adriatic Sea environmental conditions  

SciTech Connect

The paper shows the remote sensing activities that ENEA is carrying out for the evaluation of Adriatic Sea environmental conditions and their modifications over the last fifteen years. The activities were requested by the Italian Research Ministry to gain knowledge of the circulation model of the Adriatic Sea and to understand what caused algae blooms in some of the last years. The Adriatic Sea is a high environmental risk sea, because its depth is low and a strong pollutant charge is coming into the sea from the Po river and from many other rivers of the NE coast of Italy. Processing of satellite images has covered the period from 1980 up to now and has allowed the reconstruction of modifications of the environmental conditions of the sea. The paper shows the first results obtained by remote sensing images processing that will be utilized for the database of the Adriatic Sea.

Vitiello, F.; Borfecchia, F.; De Cecco, L.; Martini, S. [ENEA, Rome (Italy)

1997-08-01

107

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.

108

Validation and application of fossil DNA as a recorder of past marine ecosystems and environmental conditions  

Microsoft Academic Search

The majority of planktonic species, including those that are informative in the reconstructions of past marine environmental conditions, do not produce diagnostic features (e.g., cysts, spores, or lipid biomarkers) and would therefore escape identification from the fossil record using traditional paleoecological tools (microscopy or lipid biomarker geochemistry). However, several studies have recently demonstrated that fossil DNA of planktonic species can

A. C. Boere

2010-01-01

109

Vegetation and environmental conditions in recently restored wetlands in the prairie pothole region of the USA  

Microsoft Academic Search

How closely the vegetation of restored wetlands resembles that of comparable natural wetlands is a function of the probability of propagules of wetland species reaching reflooded wetlands and how similar environmental conditions in the restored wetland are those in the natural wetlands. Three years after reflooding, we examined the vegetation composition, water level fluctuations, soil organic carbon content, and soil

Susan M. Galatowitsch; Arnold G. van der Valk

1996-01-01

110

Modeling Effects of Relative Humidity, Moisture, and Extreme Environmental Conditions on Power Electronic Performance  

E-print Network

in the air are Absolute and Relative Humidity: Absolute Humidity is defined as the amount of water vaporModeling Effects of Relative Humidity, Moisture, and Extreme Environmental Conditions on Power Dept. Elect. &Comp. Eng Northeastern University Boston, MA 02115 lehman@ece.neu.edu Abstract

Lehman, Brad

111

Bacterivory of a mudflat nematode community under different1 environmental conditions2  

E-print Network

1 Bacterivory of a mudflat nematode community under different1 environmental conditions2 Pierre fauna. The trophic role of bacteria for a nematode community on the Brouage mudflat14 (Marennes of bacteria by nematodes. In order to assess simultaneously bacteria and algal21 assimilation rates, algal

Paris-Sud XI, Université de

112

Relationships between microbial community structure and soil environmental conditions in a recently burned system  

Microsoft Academic Search

Most wildfires, even the most severe, burn at mixed intensities across a landscape, depending on local fuel loads, fuel moistures, and wind strength and direction. This heterogeneous patchwork of fire effects can influence the patterns of above- and belowground biotic recovery through altered environmental conditions, nutrient availability, and biotic sources for microbial and vegetative re-colonization. We quantified the effects of

Sarah T. Hamman; Ingrid C. Burke; Mary E. Stromberger

2007-01-01

113

Recombinative Generalization: Relationships between Environmental Conditions and the Linguistic Repertoires of Language Learners.  

ERIC Educational Resources Information Center

Research on the environmental conditions promoting generative language learning is reviewed. Recombinative generalization is introduced as a principle of stimulus control that enables individuals to express and to comprehend novel utterances. Alternative matrix-training procedures should be considered in attempts to optimize the development of…

Goldstein, Howard

1983-01-01

114

Insects, diseases, animals and environmental conditions can all injure holly plants. Monitor your plants frequently,  

E-print Network

Insects, diseases, animals and environmental conditions can all injure holly plants. Monitor your disorders. Chewing Insects Holly leaf miners are chewing insects that feed on hollies, preferably American insects feed on plant roots. The two- banded Japanese weevil feeds in the daytime, but is easily

Liskiewicz, Maciej

115

The transactional psychobiological nature of cognitive appraisal during exercise in environmentally stressful conditions  

Microsoft Academic Search

Background and Purpose: Successful adaptation to the stress of physical exertion in adverse environmental conditions (heat, cold, high altitude) is of great concern when optimal performance within safe parameters is the goal. The perception of the psychophysical demands imposed by the stressful situation and the perceived capability to cope with these demands is a process that can dramatically alter the

Edmund O. Acevedo; Panteleimon Ekkekakis

2001-01-01

116

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

117

Positive and negative interactions between environmental conditions affecting Cercocarpus ledifolius seedling survival  

Microsoft Academic Search

We evaluated the balance between positive and negative effects of environmental conditions on first-year seedling survival of the tree Cercocarpus ledifolius during two summers, 1996 and 1997. The experimental design was fully crossed with two levels of water, with and without supplementation, two levels of herbivory, with and without protection, and three major microhabitats, open interspaces, under the canopy of

Inés Ibáñez; Eugene W. Schupp

2001-01-01

118

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. PMID:19350941

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

2013-01-01

119

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

120

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

121

Sleep deprivation impairs the extinction of cocaine-induced environmental conditioning in mice.  

PubMed

Persistence of a drug-environment conditioning induced by repeated psychostimulant treatment is thought to play a key role in the addictive cycle. In addition, sleep disorders are a common feature in patients with addictive disorders. Sleep deprivation shares similar neurobiological effects with psychostimulants. Therefore, we investigated whether sleep deprivation would impair the extinction of previously established conditioning between the drug effect and the environmental cues. Four cohorts of male adult mice underwent a behavioral sensitization procedure pairing drug (cocaine at 15mg/kg, i.p.) or saline with environment (open-field apparatus). The extinction of conditioned locomotion was evaluated after control (home-cage maintained) or sleep deprivation (gentle handling method for 6h) conditions. Sleep deprivation both postponed the initiation and impaired the completeness of extinction of the conditioned locomotion promoted by previous drug-environment conditioning in cocaine-sensitized animals. While the cocaine control group required 5 free-drug sessions of exposure to the open-field apparatus to complete extinction of conditioned locomotion, the cocaine pre-treated group that experienced sleep deprivation before each extinction session still significantly differed from its respective control group on Day 5 of extinction. The possibility that the sleep condition can influence the extinction of a long-lasting association between drug effects and environmental cues can represent new outcomes for clinically relevant phenomena. PMID:24836180

Berro, L F; Hollais, A W; Patti, C L; Fukushiro, D F; Mári-Kawamoto, E; Talhati, F; Costa, J M; Zanin, K A; Lopes-Silva, L B; Ceccon, L M; Santos, R; Procópio-Souza, R; Trombin, T F; Yokoyama, T S; Wuo-Silva, R; Tufik, S; Andersen, M L; Frussa-Filho, R

2014-09-01

122

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

123

Effect of environmental conditions on the fatty acid fingerprint of microbial communities  

NASA Astrophysics Data System (ADS)

Lipid biomarkers, especially phospholipids, are routinely used to characterize microbial community structure in environmental samples. Interpretations of these fingerprints mainly depend on rare results of pure cultures which were cultivated under standardized batch conditions. However, membrane lipids (e.g. phopholipid biomarker) build up the interface between microorganisms and their environment and consequently are prone to be adapted according to the environmental conditions. We cultivated several bacteria, isolated from soil (gram-positive and gram-negative) under various conditions e.g. C supply and temperature regimes. Effect of growth conditions on phospholipids fatty acid (PLFA) as well as neutral lipid fatty acids (NLFA) and glycolipid fatty acids (GLFA) was investigated by conventional method of extraction and derivatization, followed by assessments with gas chromatography mass spectrometry (GC-MS). In addition, phospholipids were measured as intact molecules by ultra high performance liquid chromatography - quadrupole - time of flight mass spectrometer (UHPLC-Q-ToF) to further assess the composition of headgroups with fatty acids residues and their response on changing environmental conditions. PLFA fingerprints revealed a strong effect of growth stage, C supply and temperature e.g. decrease of temperature increased the amount of branched and/or unsaturated fatty acids to maintain the membrane fluidity. This strongly changes the ratio of specific to unspecific fatty acids depending on environmental conditions. Therefore, amounts of specific fatty acids cannot be used to assess biomass of a functional microbial group in soil. Intracellular neutral lipids depended less on environmental conditions reflecting a more stable biomarker group but also showed less specific fatty acids then PLFA. Therefore, combination of several lipid classes is suggested as more powerful tool to assess amounts and functionality of environmental microbial communities. Further information was gained from the analysis of intact polar lipids. Ethanolamines and cholines were the most abundant head groups within bacteria and are mainly combined with one specific and one unspecific fatty acid. Reactions on changing environmental conditions occurred mainly by modifications of fatty acids and rarely by a change of the headgroup fingerprint. This approach thus enables to categorize a certain amount of formerly unspecific fatty acids towards a specific microbial group. Ecological understanding for the interface between surrounding environment and cellular metabolism could be deepened by investigating the intact compounds e.g. intact phospholipids of microbial membranes. However, data from further organisms as well as diverse microbial communities are needed to continue the databases of intact phospholipids. Further investigations of diverse microbial communities under changing environmental conditions have to follow these first studies to 1) assess the effects of soil environment on microbial membranes (e.g. associations in biofilms) and 2) assess the effect of interspecific microbial interactions on their membrane properties and lipid fingerprints. Thus, combination of various lipid biomarkers as well as their intact characterization enables a more detailed look into microbial community structure and their respond on environmental conditions, improves our understanding of microbial functioning in ecosystems and enables a more specific estimation of biomass of various microbial groups.

Biryukov, Mikhail; Dippold, Michaela; Kuzyakov, Yakov

2014-05-01

124

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

125

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

126

Insula response to unpredictable and predictable aversiveness in individuals with panic disorder and comorbid depression  

PubMed Central

Background Prior studies suggest that hyperactive insula responding to unpredictable aversiveness is a core feature of anxiety disorders. However, no study to date has investigated the neural correlates of unpredictable aversiveness in those with panic disorder (PD) with comorbid major depressive disorder (MDD). The aim of the current study was to examine group differences in neural responses to unpredictable and predictable aversiveness in 41 adults with either 1) current PD with comorbid MDD (PD-MDD), 2) current MDD with no lifetime diagnosis of an anxiety disorder (MDD-only), or 3) no lifetime diagnosis of psychopathology. All participants completed a functional magnetic resonance imaging (fMRI) scan while viewing temporally predictable or unpredictable negative or neutral images. Findings The results indicated that individuals with PD-MDD exhibited greater bilateral insula activation to unpredictable aversiveness compared with controls and individuals with MDD-only (who did not differ). There were no group differences in insula activation to predictable aversiveness. Conclusions These findings add to a growing literature highlighting the role of the insula in the pathophysiology of anxiety disorders. PMID:25337388

2014-01-01

127

Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean.  

PubMed

Concentrations and species of iodine isotopes ((127)I and (129)I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic (129)I in the Arctic Ocean and the Nordic Seas, concentrations of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on (129)I and (127)I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30° and 50°N. The results show iodate as the predominant species in the analyzed marine waters for both (127)I and (129)I. Despite the rather constant ratios of (127)I(-)/(127)IO3(-), the (129)I(-)/(129)IO3(-) values reveal variations that apparently response to sources, environmental conditions and residence time. These findings provide a new tracer approach that will strongly enhance the application of anthropogenic (129)I in ocean environments and impact on climate at the ocean boundary layer. PMID:24284916

He, Peng; Hou, Xiaolin; Aldahan, Ala; Possnert, Göran; Yi, Peng

2013-01-01

128

Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean  

PubMed Central

Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on 129I and 127I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30° and 50°N. The results show iodate as the predominant species in the analyzed marine waters for both 127I and 129I. Despite the rather constant ratios of 127I?/127IO3?, the 129I?/129IO3? values reveal variations that apparently response to sources, environmental conditions and residence time. These findings provide a new tracer approach that will strongly enhance the application of anthropogenic 129I in ocean environments and impact on climate at the ocean boundary layer. PMID:24284916

He, Peng; Hou, Xiaolin; Aldahan, Ala; Possnert, Goran; Yi, Peng

2013-01-01

129

Food web expansion and contraction in response to changing environmental conditions.  

PubMed

Macroscopic ecosystem properties, such as major material pathways and community biomass structure, underlie the ecosystem services on which humans rely. While ecologists have long sought to identify the determinants of the trophic height of food webs (food chain length), it is somewhat surprising how little research effort is invested in understanding changes among other food web properties across environmental conditions. Here we theoretically and empirically show how a suite of fundamental macroscopic food web structures respond, in concert, to changes in habitat accessibility using post-glacial lakes as model ecosystems. We argue that as resource accessibility increases in coupled food webs, food chain length contracts (that is, reduced predator trophic position), habitat coupling expands (that is, increasingly coupled macrohabitats) and biomass pyramid structure becomes more top heavy. Our results further support an emerging theoretical view of flexible food webs that provides a foundation for generally understanding ecosystem responses to changing environmental conditions. PMID:23033081

Tunney, Tyler D; McCann, Kevin S; Lester, Nigel P; Shuter, Brian J

2012-01-01

130

Dichromated pullulan diffraction gratings: influence of environmental conditions and storage time on their properties  

NASA Astrophysics Data System (ADS)

Investigations of the environmental stability of diffraction gratings, recorded in dichromated pullulan (DCP), are reported. Profile changes of DCP surface relief gratings, under high humidity conditions, were analyzed using an atomic force microscope. It was found that the profile was not altered, while the diffraction efficiency was preserved. The influence of storage life on the diffraction efficiency and surface profile of DCP gratings were also investigated. It was concluded that DCP gratings offer much better stability compared with the dichromated gelatin.

Savi? Ševi?, Svetlana; Panteli?, Dejan

2007-01-01

131

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

Microsoft Academic Search

STUDY OBJECTIVETo examine the association between exposure to environmental tobacco smoke (ETS) and demographic, lifestyle, occupational characteristics and self reported health conditions.DESIGNCross sectional study, using data from multiphasic health checkups between 1979 and 1985.SETTINGLarge health plan in Northern California, USA.PARTICIPANTS16 524 men aged 15–89 years and 26 197 women aged 15–105 years who never smoked.RESULTSSixty eight per cent of men

C Iribarren; G D Friedman; A L Klatsky; M D Eisner

2001-01-01

132

Dynamic polarization fluctuation characteristics of optical fiber submarine cables under various environmental conditions  

Microsoft Academic Search

Polarization fluctuation characteristics of optical-fiber submarine cable under 8000-m-deep sea environmental conditions, optical-fiber submarine cable coupling under periodic variable tension, and cable performance during and after installation, are presented. As a worst case, it is demonstrated that the maximum frequency spectrum of polarization fluctuation is less than 200 Hz under dynamic composite stress states. It is found that the polarization

Yoshinori Namihira; Yukio Horiuchi; Shiro Ryu; Kiyofumi Mochizuki; Hiroharu Wakabayashi

1988-01-01

133

Effect of environmental conditions on biological decolorization of textile dyestuff by C. versicolor  

Microsoft Academic Search

Effects of environmental conditions such as pH, media composition, carbon and nitrogen sources, TOC\\/N ratio, and dyestuff concentrations on decolorization of reactive phytalocyanin type textile dyestuff Everzol Turquoise Blue G by white rot fungi, Coriolus versicolor MUCL were investigated. pH = 4.5 and the media III were found to be the most suitable ones among the others tested. Compared to

Ilgi Karapinar Kapdan; Fikret Kargia; Geoffrey McMullan; Roger Marchant

2000-01-01

134

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. PMID:21676927

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

2011-01-01

135

Learning What to Eat: Studying Inter-relations Between Learning, Grouping, and Environmental Conditions in an Artificial World  

Microsoft Academic Search

In this paper we develop an artiflcial world model to investi- gate how environmental conditions afiect opportunities for learning. We model grouping entities that learn what to eat in a 2D environment. We study diet development and focus on the social consequences of individ- ual learning in relation to difierent environmental conditions. We flnd that homogeneous and patchy environments have

Daniel J. Van Der Post; Paulien Hogeweg

2004-01-01

136

Journal of Composites for Construction Effect of Dynamic Loading and Environmental Conditions on the Bond between CFRP  

E-print Network

on the Bond between CFRP and Steel: State-of-the-Art Review --Manuscript Draft-- Manuscript Number: Full Title: Effect of Dynamic Loading and Environmental Conditions on the Bond between CFRP and Steel: State, CFRP, dynamic loading, environmental conditions, steel structures Abstract: Effect of Dynamic Loading

137

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

138

Symbolic Dynamics and Unpredictability Defined by Right Adjointness  

NASA Astrophysics Data System (ADS)

It is shown that a category-theoretic definition of chaotic system applies not only to the Smale horseshoe, a prototypical example, but also to Conway's "Life." Symbolic dynamics of the "Dining Philosophers" relational system is computed. A category composed of stochastic matrices is defined and its elementary properties are studied. A categorical variant of symbolic dynamics is applied to a finite stochastic process. Using point-wise Kan extension formulas, conditions ensuring existence of certain representations between categories of dynamic systems are proved.

Wojtowicz, Ralph L.

2004-08-01

139

Effect of environmental deterioration on buildings: a condition assessment case study  

NASA Astrophysics Data System (ADS)

The deterioration of structures due to corrosion is probably the most significant factor for their damaging condition and the need for maintenance. Corrosion mechanisms depend on the environmental conditions and the geographic characteristics of the area. In this paper a condition assessment methodology is presented through an application on a deteriorated building in Cyprus. The methodology's starting point is the collection of information through Google Earth for classification of buildings in regions based on their environmental and geographic characteristics. Through this screening process, buildings in each defined region are selected for evaluation. The following steps of the methodology include testing on selected structural members for the estimation of the compression strength and the depth of carbonation. The results of the case study, are used from the responsible engineer to evaluate the current condition of the building regarding its structural integrity and the effect of corrosion. The testing data showed that the current building strength is lower than the code's requirements and that carbonation induced corrosion must be addressed to prevent further damage.

Christou, George; Tantele, Elia A.; Votsis, Renos A.

2014-08-01

140

Avian migrants adjust migration in response to environmental conditions en route.  

PubMed

The onset of migration in birds is assumed to be primarily under endogenous control in long-distance migrants. Recently, climate changes appear to have been driving a rapid change in breeding area arrival. However, little is known about the climatic factors affecting migratory birds during the migration cycle, or whether recently reported phenological changes are caused by plastic behavioural responses or evolutionary change. Here, we investigate how environmental conditions in the wintering areas as well as en route towards breeding areas affect timing of migration. Using data from 1984 to 2004 covering the entire migration period every year from observatories located in the Middle East and northern Europe, we show that passage of the Sahara Desert is delayed and correlated with improved conditions in the wintering areas. By contrast, migrants travel more rapidly through Europe, and adjust their breeding area arrival time in response to improved environmental conditions en route. Previous studies have reported opposing results from a different migration route through the Mediterranean region (Italy). We argue that the simplest explanation for different phenological patterns at different latitudes and between migratory routes appears to be phenotypic responses to spatial variability in conditions en route. PMID:18700199

Tøttrup, Anders P; Thorup, Kasper; Rainio, Kalle; Yosef, Reuven; Lehikoinen, Esa; Rahbek, Carsten

2008-12-23

141

The antidepressant effect of an antiulcer pentadecapeptide BPC 157 in Porsolt's test and chronic unpredictable stress in rats. A comparison with antidepressants.  

PubMed

Various antidepressants have antiulcer activity. Likewise, the models currently used in ulcers and depression disorders research have a considerable degree of similarity. Therefore, the possibility that depression disorders could be effectively influenced by a primary antiulcer agent with a cyto/organoprotective activity, such as the novel stomach pentadecapeptide BPC 157, was investigated in two rat depression assays. First, a forced swimming test (a Porsolt's procedure) was used. As a more severe procedure, chronic unpredictable stress (after 5 d of unpredictable stress protocol, once daily drug application during stress procedure, open field-immobility test assessment at fourth or sixth day of medication) was used. In a forced swimming test, a reduction of the immobility time in BPC 157 (10 microg, 10 ng x kg(-1) i.p.) treated rats corresponds to the activity of the 15 mg or 40 mg (i.p.) of conventional antidepressants, imipramine or nialamide, respectively, given according to the original Porsolt's protocol. In chronic unpredictable stress procedure, particular aggravation of experimental conditions markedly affected the conventional antidepressant activity, whereas BPC 157 effectiveness was continuously present. The effect of daily imipramine (30 mg) medication could be seen only after a more prolonged period, but not after a shorter period (i.e., 4-d protocol). In these conditions, no delay in the effectiveness was noted in BPC 157 medication and a reduction of the immobility of chronically stressed rats was noted after both 4 and 6 d of BPC 157 (10 microg, 10 ng) medication. PMID:10791689

Sikiric, P; Separovic, J; Buljat, G; Anic, T; Stancic-Rokotov, D; Mikus, D; Marovic, A; Prkacin, I; Duplancic, B; Zoricic, I; Aralica, G; Lovric-Bencic, M; Ziger, T; Perovic, D; Rotkvic, I; Mise, S; Hanzevacki, M; Hahn, V; Seiwerth, S; Turkovic, B; Grabarevic, Z; Petek, M; Rucman, R

2000-01-01

142

BILL E. KUNKLE INTERDISCIPLINARY BEEF SYMPOSIUM: Animal welfare concerns for cattle exposed to adverse environmental conditions.  

PubMed

Increasing awareness of animal welfare has become a priority in food production systems involving animals. Under normal working environments, production practices are constantly evaluated to maintain optimum levels of animal well-being. However, during periods of adverse weather, optimum conditions for animal comfort, as well as animal performance, are often compromised. In the Midwest and Great Plains states, the heat waves of 1995, 1999, 2006, 2009, 2010, and 2013 were particularly difficult on animals reared in confinement, with documented cattle losses approaching 5,000 head each year. Additionally, during the summer of 2011, nearly 15,000 head of cattle across 5 states were lost as a result of heat stress. During prolonged periods of heat stress, lower conceptions rates are observed in livestock. In addition, animals reared in confinement buildings are often compromised because of limitations in ventilation systems. Under the opposite environmental spectrum, the winters of 1992 to 1993, 1996 to 1997, 1997 to 1998, 2006 to 2007, and 2008 to 2009 caused hardship for livestock producers, particularly for those rearing animals in an outdoor environment. During the winters of 1996 to 1997 and 2008 to 2009 up to 50% of the newborn calves were lost in many areas, with over 75,000 head of cattle lost in the northern plains states. Late fall and early winter snowstorms in 1992, 1997, 2006, and 2013 resulted in the loss of over 25,000 head of cattle each year in the Great Plains region of the United States. Economic losses from reduced performance of cattle experiencing severe environmental stress likely exceed losses associated with livestock death by 5- to 10-fold. Use of alternative supplementation programs may need to be considered for livestock challenged by adverse environmental conditions. Use of additional water for consumption and cooling, shade, and/or alternative management strategies need to be considered to help livestock cope with heat stress. For animals reared outside during the winter, strategies that increase animal space and environmental buffers need to be employed to minimize effects of mud, wet conditions, and wind chill. The above-mentioned weather events suggest that there are ample opportunities for livestock producers to enhance animal welfare and minimize impact of environmental stress. Caretakers need a greater understanding of animal responses to weather challenges to help animals cope with adverse climatic conditions. PMID:25414102

Mader, T L

2014-12-01

143

Clothing insulation and temperature, layer and mass of clothing under comfortable environmental conditions.  

PubMed

This study was designed to investigate the relationship between the microclimate temperature and clothing insulation (Icl) under comfortable environmental conditions. In total, 20 subjects (13 women, 7 men) took part in this study. Four environmental temperatures were chosen: 14°C (to represent March/April), 25°C (May/June), 29°C (July/August), and 23°C (September/October). Wind speed (0.14ms-1) and humidity (45%) were held constant. Clothing microclimate temperatures were measured at the chest (Tchest) and on the interscapular region (Tscapular). Clothing temperature of the innermost layer (Tinnermost) was measured on this layer 30 mm above the centre of the left breast. Subjects were free to choose the clothing that offered them thermal comfort under each environmental condition. We found the following results. 1) All clothing factors except the number of lower clothing layers (Llower), showed differences between the different environmental conditions (P<0.05). The ranges of Tchest were 31.6 to 33.5°C and 32.2 to 33.4°C in Tscapular. The range of Tinnermost was 28.6 to 32.0°C. The range of the upper clothing layers (Lupper) and total clothing mass (Mtotal) was 1.1 to 3.2 layers and 473 to 1659 g respectively. The range of Icl was 0.78 to 2.10 clo. 2) Post hoc analyses showed that analysis of Tinnermost produced the same results as for that of Icl. Likewise, the analysis of Lupper produced the same result as the analysis of the number of total layers (Ltotal) within an outfit. 3) Air temperature (ta) had positive relationships with Tchest and Tscapular and with Tinnermost but had inverse correlations with Icl, Mtotal, Lupper and Ltotal. Tchest, Tscapular, and Tinnermost increased as ta rose. 4) Icl had inverse relationships with Tchest and Tinnermost, but positive relationships with Mtotal, Lupper and Ltotal. Icl could be estimated by Mtotal, Lupper, and Tscapular using a multivariate linear regression model. 5) Lupper had positive relationships with Icl and Mtotal, but Llower did not. Subjects hardly changed Llower under environmental comfort conditions between March and October. This indicates that each of the Tchest, Mtotal, and Lupper was a factor in predicting Icl. Tinnermost might also be a more influential factor than the clothing microclimate temperature. PMID:23816370

Kwon, JuYoun; Choi, Jeongwha

2013-01-01

144

Modeling territory attendance and preening behavior in a seabird colony as functions of environmental conditions.  

PubMed

In previous studies we developed a general compartmental methodology for modeling animal behavior and applied the methodology to marine birds and mammals. In this study we used the methodology to construct a system of two differential equations to model the dynamics of territory attendance and preening in a gull colony on Protection Island, Strait of Juan de Fuca, Washington. We found that colony occupancy was driven primarily by abiotic environmental conditions, including tide height, time of day, solar elevation, and wind speed over open water. For birds in the colony, preening behavior was driven to some extent by abiotic environmental conditions (including time of day, solar elevation, humidity, and wind speed on the colony), but apparently was driven primarily by local and/or biotic effects not included in the model. In terms of R(2) values, the model explained 65% and 37% of the variability in colony occupancy and preening data, respectively, as a function of these six abiotic environmental factors. PMID:22880615

Henson, Shandelle M; Galusha, Joseph G; Hayward, James L; Cushing, J M

2007-01-01

145

Useful model organisms, indicators, or both? Ground beetles (Coleoptera, Carabidae) reflecting environmental conditions  

PubMed Central

Abstract Classic studies have successfully linked single-species abundances, life-history traits, assemblage structures and biomass of carabid beetles to past and present, human-caused environmental impacts and variation in ‘natural’ conditions. This evidence has led many to suggest carabids to function as ‘indicators’ ? a term that bears multiple meanings. Here, a conservation-oriented definition for an indicator is used, carabid indicator potential from seven views is evaluated, and ways to proceed in indicator research are discussed. (1) Carabid species richness poorly indicates the richness and abundance of other taxa, which underlines the importance of using multiple taxa in environmental assessments. The ability of assemblage indices and specialist or functional-group abundances to reflect rare species and habitats should be examined in detail. (2) Experimental evidence suggests that carabids may potentially serve as keystone indicators. (3) Carabids are sensitive to human-altered abiotic conditions, such as pesticide use in agro-ecosystems and heavy metal contamination of soils. Carabids might thus reflect ecological sustainability and ‘ecosystem health’. (4) Carabid assemblages host abundant species characteristic of particular habitat types or successional stages, which makes them promising dominance indicators. (5) Carabids reflect variation in ‘natural’ conditions, but vegetation and structural features are more commonly adopted as condition indicators. Carabids nevertheless provide yet another, equally accurate, view on the structure of the environment. (6) Carabids may function as early-warning signalers, as suggested by recent studies linking climate and carabid distributions. (7) Carabids reflect natural and human-caused disturbances and management, but the usefulness of these responses for conservation purposes requires further research. In summary, European carabids appear useful model organisms and possibly indicators because they are diverse, taxonomically and ecologically well-known, efficiently reflect biotic and abiotic conditions, are relevant at multiple spatial scales, and are easy to collect in sufficiently large numbers to allow statistical analyses. The assumption that carabid responses would reflect rare environmental conditions or the responses of rare and threatened species ? crucial information for conservationists and managers ? has not yet been critically evaluated. Even if it holds, the usefulness will be context dependent: species and their populations vary, conditions vary, questions put forward vary, and assessment goals vary. PMID:21738418

Koivula, Matti J.

2011-01-01

146

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

147

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. PMID:21311768

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

2011-01-01

148

Hormonal Signal Amplification Mediates Environmental Conditions during Development and Controls an Irreversible Commitment to Adulthood  

PubMed Central

Many animals can choose between different developmental fates to maximize fitness. Despite the complexity of environmental cues and life history, different developmental fates are executed in a robust fashion. The nematode Caenorhabditis elegans serves as a powerful model to examine this phenomenon because it can adopt one of two developmental fates (adulthood or diapause) depending on environmental conditions. The steroid hormone dafachronic acid (DA) directs development to adulthood by regulating the transcriptional activity of the nuclear hormone receptor DAF-12. The known role of DA suggests that it may be the molecular mediator of environmental condition effects on the developmental fate decision, although the mechanism is yet unknown. We used a combination of physiological and molecular biology techniques to demonstrate that commitment to reproductive adult development occurs when DA levels, produced in the neuroendocrine XXX cells, exceed a threshold. Furthermore, imaging and cell ablation experiments demonstrate that the XXX cells act as a source of DA, which, upon commitment to adult development, is amplified and propagated in the epidermis in a DAF-12 dependent manner. This positive feedback loop increases DA levels and drives adult programs in the gonad and epidermis, thus conferring the irreversibility of the decision. We show that the positive feedback loop canalizes development by ensuring that sufficient amounts of DA are dispersed throughout the body and serves as a robust fate-locking mechanism to enforce an organism-wide binary decision, despite noisy and complex environmental cues. These mechanisms are not only relevant to C. elegans but may be extended to other hormonal-based decision-making mechanisms in insects and mammals. PMID:22505848

Schaedel, Oren N.; Gerisch, Birgit; Antebi, Adam; Sternberg, Paul W.

2012-01-01

149

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

150

[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

2005-01-01

151

Genomic sweep and potential genetic rescue during limiting environmental conditions in an isolated wolf population  

PubMed Central

Genetic rescue, in which the introduction of one or more unrelated individuals into an inbred population results in the reduction of detrimental genetic effects and an increase in one or more vital rates, is a potentially important management tool for mitigating adverse effects of inbreeding. We used molecular techniques to document the consequences of a male wolf (Canis lupus) that immigrated, on its own, across Lake Superior ice to the small, inbred wolf population in Isle Royale National Park. The immigrant's fitness so exceeded that of native wolves that within 2.5 generations, he was related to every individual in the population and his ancestry constituted 56 per cent of the population, resulting in a selective sweep of the total genome. In other words, all the male ancestry (50% of the total ancestry) descended from this immigrant, plus 6 per cent owing to the success of some of his inbred offspring. The immigration event occurred in an environment where space was limiting (i.e. packs occupied all available territories) and during a time when environmental conditions had deteriorated (i.e. wolves' prey declined). These conditions probably explain why the immigration event did not obviously improve the population's demography (e.g. increased population numbers or growth rate). Our results show that the beneficial effects of gene flow may be substantial and quickly manifest, short-lived under some circumstances, and how the demographic benefits of genetic rescue might be masked by environmental conditions. PMID:21450731

Adams, Jennifer R.; Vucetich, Leah M.; Hedrick, Philip W.; Peterson, Rolf O.; Vucetich, John A.

2011-01-01

152

Thermal Cyclic Behavior of Thermal and Environmental Barrier Coatings Investigated Under High-Heat-Flux Conditions  

NASA Technical Reports Server (NTRS)

Environmental barrier coatings (EBC's) have been developed to protect silicon-carbide- (SiC) based ceramic components in gas turbine engines from high-temperature environmental attack. With continuously increasing demands for significantly higher engine operating temperature, future EBC systems must be designed for both thermal and environmental protection of the engine components in combustion gases. In particular, the thermal barrier functions of EBC's become a necessity for reducing the engine-component thermal loads and chemical reaction rates, thus maintaining the required mechanical properties and durability of these components. Advances in the development of thermal and environmental barrier coatings (TBC's and EBC's, respectively) will directly impact the successful use of ceramic components in advanced engines. To develop high-performance coating systems, researchers must establish advanced test approaches. In this study, a laser high-heat-flux technique was employed to investigate the thermal cyclic behavior of TBC's and EBC's on SiC-reinforced SiC ceramic matrix composite substrates (SiC/SiC) under high thermal gradient and thermal cycling conditions. Because the laser heat flux test approach can monitor the coating's real-time thermal conductivity variations at high temperature, the coating thermal insulation performance, sintering, and delamination can all be obtained during thermal cycling tests. Plasma-sprayed yttria-stabilized zirconia (ZrO2-8 wt% Y2O3) thermal barrier and barium strontium aluminosilicate-based environmental barrier coatings (BSAS/BSAS+mullite/Si) on SiC/SiC ceramic matrix composites were investigated in this study. These coatings were laser tested in air under thermal gradients (the surface and interface temperatures were approximately 1482 and 1300 C, respectively). Some coating specimens were also subject to alternating furnace cycling (in a 90-percent water vapor environment at 1300 C) and laser thermal gradient cycling tests (in air), to investigate the water vapor effect. All cyclic tests were conducted using a 60-min hot-time temperature.

Zhu, Dongming; Lee, Kang N.; Miller, Robert A.

2002-01-01

153

Unpredictable chronic stress-induced reproductive suppression associated with the decrease of kisspeptin immunoreactivity in male mice.  

PubMed

Environmental stress affects various parts of mammals typically through the circulation of stress hormones. It has been identified as one of the possible reasons for male reproductive difficulties, but the complex mechanisms responsible for stress-induced reproductive suppression are poorly understood. Here, we examined the relationship between chronic environmental stress and hypothalamic kisspeptin, a recently discovered upstream regulator of the reproductive endocrine feedback system. We studied male mice under an unpredictable chronic stress procedure to replicate the situation of animals under chronic stress. Histological and immunohistochemical analyses were performed focusing on kisspeptin neurons in the arcuate hypothalamic nucleus (ARC) and DNA fragmented cells in seminiferous tubules. Although the ARC was not morphologically altered in either the stressed or non-stressed group, granular kisspeptin immunoreactivities decreased slightly in the stress group. In the testes of the stress group, several signs of testicular degeneration were observed, including increased numbers of ssDNA-positive cells per seminiferous tubule, thinning, vacuoled seminiferous epithelia and multinucleated giant cells. The decreases in kisspeptin in the stress group might be due to other hypothalamic peptides, such as corticotropin-releasing hormone and leptin, whose receptors are known to coexpress in the ARC. In addition, environmental stress directly and indirectly affects testicular function through stress hormones and gonadotropins. In summary, our findings enhance the understanding of stress-induced reproductive suppression possibly mediated by kisspeptin in the ARC. PMID:24871549

Hirano, Tetsushi; Kobayashi, Yoshihiro; Omotehara, Takuya; Tatsumi, Atsutoshi; Hashimoto, Rie; Umemura, Yuria; Nagahara, Daichi; Mantani, Youhei; Yokoyama, Toshifumi; Kitagawa, Hiroshi; Hoshi, Nobuhiko

2014-10-01

154

Unpredictable Chronic Stress-Induced Reproductive Suppression Associated with the Decrease of Kisspeptin Immunoreactivity in Male Mice  

PubMed Central

ABSTRACT Environmental stress affects various parts of mammals typically through the circulation of stress hormones. It has been identified as one of the possible reasons for male reproductive difficulties, but the complex mechanisms responsible for stress-induced reproductive suppression are poorly understood. Here, we examined the relationship between chronic environmental stress and hypothalamic kisspeptin, a recently discovered upstream regulator of the reproductive endocrine feedback system. We studied male mice under an unpredictable chronic stress procedure to replicate the situation of animals under chronic stress. Histological and immunohistochemical analyses were performed focusing on kisspeptin neurons in the arcuate hypothalamic nucleus (ARC) and DNA fragmented cells in seminiferous tubules. Although the ARC was not morphologically altered in either the stressed or non-stressed group, granular kisspeptin immunoreactivities decreased slightly in the stress group. In the testes of the stress group, several signs of testicular degeneration were observed, including increased numbers of ssDNA-positive cells per seminiferous tubule, thinning, vacuoled seminiferous epithelia and multinucleated giant cells. The decreases in kisspeptin in the stress group might be due to other hypothalamic peptides, such as corticotropin-releasing hormone and leptin, whose receptors are known to coexpress in the ARC. In addition, environmental stress directly and indirectly affects testicular function through stress hormones and gonadotropins. In summary, our findings enhance the understanding of stress-induced reproductive suppression possibly mediated by kisspeptin in the ARC. PMID:24871549

HIRANO, Tetsushi; KOBAYASHI, Yoshihiro; OMOTEHARA, Takuya; TATSUMI, Atsutoshi; HASHIMOTO, Rie; UMEMURA, Yuria; NAGAHARA, Daichi; MANTANI, Youhei; YOKOYAMA, Toshifumi; KITAGAWA, Hiroshi; HOSHI, Nobuhiko

2014-01-01

155

Responses of five Mediterranean halophytes to seasonal changes in environmental conditions  

PubMed Central

In their natural habitats, different mechanisms may contribute to the tolerance of halophytes to high soil salinity and other abiotic stresses, but their relative contribution and ecological relevance, for a given species, remain largely unknown. We studied the responses to changing environmental conditions of five halophytes (Sarcocornia fruticosa, Inula crithmoides, Plantago crassifolia, Juncus maritimus and J. acutus) in a Mediterranean salt marsh, from summer 2009 to autumn 2010. A principal component analysis was used to correlate soil and climatic data with changes in the plants' contents of chemical markers associated with stress responses: ions, osmolytes, malondialdehyde (MDA, a marker of oxidative stress) and antioxidant systems. Stress tolerance in S. fruticosa, I. crithmoides and P. crassifolia (all succulent dicots) seemed to depend mostly on the transport of ions to aerial parts and the biosynthesis of specific osmolytes, whereas both Juncus species (monocots) were able to avoid accumulation of toxic ions, maintaining relatively high K+/Na+ ratios. For the most salt-tolerant taxa (S. fruticosa and I. crithmoides), seasonal variations of Na+, Cl?, K+ and glycine betaine, their major osmolyte, did not correlate with environmental parameters associated with salt or water stress, suggesting that their tolerance mechanisms are constitutive and relatively independent of external conditions, although they could be mediated by changes in the subcellular compartmentalization of ions and compatible osmolytes. Proline levels were too low in all the species to possibly have any effect on osmotic adjustment. However—except for P. crassifolia—proline may play a role in stress tolerance based on its ‘osmoprotectant’ functions. No correlation was observed between the degree of environmental stress and the levels of MDA or enzymatic and non-enzymatic antioxidants, indicating that the investigated halophytes are not subjected to oxidative stress under natural conditions and do not, therefore, need to activate antioxidant defence mechanisms. PMID:25139768

Gil, Ricardo; Bautista, Inmaculada; Boscaiu, Monica; Lidón, Antonio; Wankhade, Shantanu; Sánchez, Héctor; Llinares, Josep; Vicente, Oscar

2014-01-01

156

Self-organized control of bipedal locomotion by neural oscillators in unpredictable environment  

Microsoft Academic Search

A new principle of sensorimotor control of legged locomotion in an unpredictable environment is proposed on the basis of neurophysiological knowledge and a theory of nonlinear dynamics. Stable and flexible locomotion is realized as a global limit cycle generated by a global entrainment between the rhythmic activities of a nervous system composed of coupled neural oscillators and the rhythmic movements

G. Taga; Y. Yamaguchi; H. Shimizu

1991-01-01

157

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

158

Influence of lairage environmental conditions and resting time on meat quality in pigs.  

PubMed

This study investigated the influence of lairage environmental conditions and resting time on pig carcasses and meat quality. The experimental material consisted of 1001 cross Pietrain-Duroc-Hampshire × Belgium-LR-LW pigs, held in lairage for either ?30 min (direct slaughter) or between 2-3 h under 12 °C/90% relative humidity (RH), 20 °C/80% or 90% RH and 35 °C/50% or 85% RH. Prior to arrival at the lairage plant they were transported for about 45-60 min and subjected to a fasting period of 36 h before loading. Unloading operation and the driving of pigs to the point of stunning were carried out according to the practices used in the plant (sticks and electrical goads were used). Batches of 20-30 mixed pigs were used in each trial, held at a stocking density of approximately 0.55 m(2)/pig (?100 Kg live weight). Lairage environmental conditions (LC), significantly affected almost all measurements, but not pH(1), in Semi-membranosus (SM) and Longissimus dorsi (LD) muscles and the carcass damage score. The influence of resting time (RT) was basically exerted on pH(u), deep ham temperature and in pH(1), of SM, the internal muscle reflectance being mostly unaffected. There were also significant batch (B) effects in a large range of parameters. Factors greatly interacted their influence on carcass and meat quality, denoting LC × B, LC × RT × B and LC × RT the most significant effects. RT × B only showed two low significant interactions for rigor value and pH(1), in SM, suggesting that, conversely to the lairage environmental conditions the influence of resting time is practically unaffected by the day of slaughter. The increase of lairage temperature decreased the frequency of normal carcasses, followed by an expressive higher incidence of PSE status. The influence of lairage relative humidity on the PSE/DFD muscle incidence depended on the associated temperature, but the most important detrimental effects were noticed in experiments carried out at 35 °C. In respect to lairage resting time, the influence on meat quality is strictly related to environmental conditions, mainly the temperature. Nevertheless, and excepting the assays at 35 °C/85% RH, direct slaughter of pigs (= 30 min in pens) generally produced less carcasses of normal quality than resting periods up to 2-3 h. PMID:22061307

Santos, C; Almeida, J M; Matias, E C; Fraqueza, M J; Roseiro, C; Sardina, L

1997-02-01

159

Stability of Middle East respiratory syndrome coronavirus (MERS-CoV) under different environmental conditions.  

PubMed

The stability of Middle East respiratory syndrome coronavirus (MERS-CoV) was determined at 20°C--40% relative humidity (RH); 30°C--30% RH and 30°C--80% RH. MERS-CoV was more stable at low temperature/low humidity conditions and could still be recovered after 48 hours. During aerosolisation of MERS-CoV, no decrease in stability was observed at 20°C--40% RH. These data suggest the potential of MERS-CoV to be transmitted via contact or fomite transmission due to prolonged environmental presence. PMID:24084338

van Doremalen, N; Bushmaker, T; Munster, V J

2013-01-01

160

Tick community composition in Midwestern US habitats in relation to sampling method and environmental conditions.  

PubMed

The ranges of many tick species are changing due to climate change and human alteration of the landscape. Understanding tick responses to environmental conditions and how sampling method influences measurement of tick communities will improve our assessment of human disease risk. We compared tick sampling by three collection methods (dragging, CO2 trapping and rodent surveys) in adjacent forested and grassland habitats in the lower Midwest, USA, and analyzed the relationship between tick abundance and microclimate conditions. The study areas were within the overlapping ranges of three tick species, which may provide conditions for pathogen exchange and spread into new vectors. Dermacentor variabilis (American dog tick) was found using all methods, Amblyomma americanum (lonestar tick) was found by dragging and CO2 trapping and Ixodes scapularis (blacklegged deer tick) was found only on rodents. Proportion of each species differed significantly among sampling methods. More ticks were found in forests compared to open habitats. Further, more ticks were collected by dragging and from rodents in hotter, drier conditions. Our results demonstrate that multiple sampling methodologies better measure the tick community and that microclimate conditions strongly influence the abundance and activity of individual tick species. PMID:24705853

Rynkiewicz, Evelyn C; Clay, Keith

2014-09-01

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. PMID:23162120

Rothstein, Steven J.

2013-01-01

162

Metabolic and Environmental Conditions Determine Nuclear Genomic Instability in Budding Yeast Lacking Mitochondrial DNA  

PubMed Central

Mitochondrial dysfunctions are an internal cause of nuclear genome instability. Because mitochondria are key regulators of cellular metabolism, we have investigated a potential link between external growth conditions and nuclear chromosome instability in cells with mitochondrial defects. Using Saccharomyces cerevisiae, we found that cells lacking mitochondrial DNA (rho0 cells) have a unique feature, with nuclear chromosome instability that occurs in nondividing cells and strongly fluctuates depending on the cellular environment. Calorie restriction, lower growth temperatures, growth at alkaline pH, antioxidants (NAC, Tiron), or presence of nearby wild-type cells all efficiently stabilize nuclear genomes of rho0 cells, whereas high glucose and ethanol boost instability. In contrast, other respiratory mutants that still possess mitochondrial DNA (RHO+) keep fairly constant instability rates under the same growth conditions, like wild-type or other RHO+ controls. Our data identify mitochondrial defects as an important driver of nuclear genome instability influenced by environmental factors. PMID:24374640

Dirick, Leon; Bendris, Walid; Loubiere, Vincent; Gostan, Thierry; Gueydon, Elisabeth; Schwob, Etienne

2014-01-01

163

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.

164

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

2014-01-01

165

The role of abiotic environmental conditions and herbivory in shaping bacterial community composition in floral nectar.  

PubMed

Identifying the processes that drive community assembly has long been a central theme in ecology. For microorganisms, a traditional prevailing hypothesis states that "everything is everywhere, but the environment selects". Although the bacterial community in floral nectar may be affected by both atmosphere (air-borne bacteria) and animals as dispersal vectors, the environmental and geographic factors that shape microbial communities in floral nectar are unknown. We studied culturable bacterial communities in Asphodelus aestivus floral nectar and in its typical herbivorous bug Capsodes infuscatus, along an aridity gradient. Bacteria were sampled from floral nectar and bugs at four sites, spanning a geographical range of 200 km from Mediterranean to semi-arid conditions, under open and bagged flower treatments. In agreement with the niche assembly hypothesis, the differences in bacterial community compositions were explained by differences in abiotic environmental conditions. These results suggest that microbial model systems are useful for addressing macro-ecological questions. In addition, similar bacterial communities were found in the nectar and on the surface of the bugs that were documented visiting the flowers. These similarities imply that floral nectar bacteria dispersal is shaped not only by air borne bacteria and nectar consumers as previously reported, but also by visiting vectors like the mirid bugs. PMID:24922317

Samuni-Blank, Michal; Izhaki, Ido; Laviad, Sivan; Bar-Massada, Avi; Gerchman, Yoram; Halpern, Malka

2014-01-01

166

Positive and negative interactions between environmental conditions affecting Cercocarpus ledifolius seedling survival.  

PubMed

We evaluated the balance between positive and negative effects of environmental conditions on first-year seedling survival of the tree Cercocarpus ledifolius during two summers, 1996 and 1997. The experimental design was fully crossed with two levels of water, with and without supplementation, two levels of herbivory, with and without protection, and three major microhabitats, open interspaces, under the canopy of Artemisia tridentata shrubs, and under the canopy of mature C. ledifolius trees. Effects of drought and herbivory on seedling survival depended on the year. Water supplementation and herbivory protection during the dry summer of 1996 (27.7 mm) generally increased seedling survival. Additionally, survival tended to be greatest beneath C. ledifolius canopies. More important ecologically were the significant interactions. In 1996, water supplementation increased survival more with than without herbivory protection. The three-way interaction, treatment-microhabitat combination, was most important; by far the greatest survival was in the water supplementation and herbivory protection in the tree microhabitat. During the wet summer of 1997 (158.5 mm), neither water supplementation, herbivory protection, nor microhabitat were significant as main effects. The water-supplemented and herbivory-protected treatment again combined to yield highest survival, but this time in open interspaces rather than beneath trees. Our study shows how the importance of individual limiting factors and the relative favorableness of particular microhabitats appear to change across years depending on environmental conditions. PMID:24577694

Ibáñez, I; Schupp, E W

2001-12-01

167

Environmental conditions and human drivers for changes to north Ethiopian mountain landscapes over 145 years.  

PubMed

As quantitative or spatially distributed studies of environmental change over truly long-term periods of more than 100 years are extremely rare, we re-photographed 361 landscapes that appear on historical photographs (1868-1994) within a 40,000 km(2) study area in northern Ethiopia. Visible evidence of environmental changes apparent from the paired photographs was analyzed using an expert rating system. The conditions of the woody vegetation, soil and water conservation structures and land management were worse in the earlier periods compared to their present conditions. The cover by indigenous trees is a notable exception: it peaked in the 1930s, declined afterwards and then achieved a second peak in the early 21st century. Particularly in areas with greater population densities, there has been a significant increase in woody vegetation and soil and water conservation structures over the course of the study period. We conclude that except for an apparent upward movement of the upper tree limit, the direct human impacts on the environment are overriding the effects of climate change in the north Ethiopian highlands and that the northern Ethiopian highlands are currently greener than at any other time in the last 145 years. PMID:24717722

Nyssen, Jan; Frankl, Amaury; Haile, Mitiku; Hurni, Hans; Descheemaeker, Katrien; Crummey, Donald; Ritler, Alfons; Portner, Brigitte; Nievergelt, Bernhard; Moeyersons, Jan; Munro, Neil; Deckers, Jozef; Billi, Paolo; Poesen, Jean

2014-07-01

168

Manipulating individual state during migration provides evidence for carry-over effects modulated by environmental conditions  

PubMed Central

Despite observational evidence of carry-over effects (COEs, events occurring in one season that produce residual effects on individuals the following seasons), to our knowledge no experimental studies have been carried out to explore how COEs might affect reproductive output. We simulated an environmental perturbation affecting spring-staging migrants to investigate COEs in greater snow geese (Anser caerulescens atlanticus). During three consecutive years, 2037 females captured during spring staging (approx. 3000 km south of their Arctic breeding grounds) were maintained in captivity (with or without access to food) for 0–4 days. Duration of captivity (but not food treatment) negatively affected reproductive success, probably through stress response. Reproductive success was reduced by 45–71% in 2 years, but not in a third year with unusually favourable breeding conditions. This unprecedented manipulation indicates that COEs can have a strong effect on individual reproductive success in long-distance migrants, but that this effect can be partly compensated for by good environmental conditions on the breeding ground. PMID:21865256

Legagneux, Pierre; Fast, Peter L. F.; Gauthier, Gilles; Bety, Joel

2012-01-01

169

Effects of environmental conditions on inducing charge structures of thunderstorms over Eastern India  

NASA Astrophysics Data System (ADS)

It is well known that environmental conditions like convective instability, aerosol loading, and availability of moisture content affect the polarity of charge structures of thunderstorms. The electrical characteristics of thunderstorms observed during the pre-monsoon season of year 2009, over Eastern India were studied to identify the effects of different environmental conditions on charge structures of thunderstorms occurring over this region. Electric field and Maxwell current data suggest that at least one of these thunderstorms had an inverted charge structure. Doppler RADAR, radiosonde, and Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth (AOD) data have been used to compare the microphysical and dynamical characteristics of these thunderstorms. The thermo dynamical structure observed by radiosonde during the day on which an inverted polarity thunderstorm was observed showed very high CAPE in the mixed-phase region compared to other thunderstorm days. Furthermore, the AOD peaked 1 day before this thunderstorm. The back trajectories of winds also suggest that the aerosols might have been transported from a desert region on that day. It has been proposed that the large ice nuclei concentration can produce dominant positive charge in the lower portion of the mixed-phase region by maintaining ice saturation.

Pawar, Sunil Dnyandeo; Gopalakrishnan, Venkatachalam; Murugavel, Palani; Sinkevich, Andrei; Lal, Deen Mani

2014-12-01

170

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

2011-04-01

171

Functional traits of selected mangrove species in Brazil as biological indicators of different environmental conditions.  

PubMed

Ecological studies on phenotypic plasticity illustrate the relevance of this phenomenon in nature. Conditions of biota reflect environmental changes, highlighting the adaptability of resident species that can be used as bioindicators of such changes. We report the morpho-anatomical plasticity of leaves of Avicennia schaueriana Stapf & Leechm. ex Moldenke, Laguncularia racemosa (L.) C.F.Gaertn. and Rhizophora mangle L., evaluated in three estuaries (Vitória bay, Santa Cruz and Itaúnas River; state of Espírito Santo, Brazil), considering five areas of mangrove ecosystems with diverse environmental issues. Two sampling sites are part of the Ecological Station Lameirão Island in Vitória bay, close to a harbor. A third sampling site in Cariacica (Vitória bay) is inside the Vitória harbor and also is influenced by domestic sewage. The fourth studied area (Santa Cruz) is part of Piraquê Mangrove Ecological Reservation, while the fifth (Itaúnas River) is a small mangrove, with sandy sediment and greater photosynthetically active radiation, also not strongly influenced by anthropic activity. Results pointed out the morpho-anatomical plasticity in studied species, showing that A. schaueriana and L. racemosa might be considered the most appropriate bioindicators to indicate different settings and environmental conditions. Particularly, the dry mass per leaf area (LMA) of A. schaueriana was the main biomarker measured. In our study, LMA of A. schaueriana was positively correlated with salinity (Spearman 0.71), Mn content (0.81) and pH (0.82) but negatively correlated with phosphorus content (-0.63). Thus, the evaluation of modification in LMA of A. schaueriana pointed out changes among five studied sites, suggesting its use to reflect changes in the environment, which could be also useful in the future to evaluate the climate change. PMID:24496023

Arrivabene, Hiulana Pereira; Souza, Iara; Có, Walter Luiz Oliveira; Rodella, Roberto Antônio; Wunderlin, Daniel Alberto; Milanez, Camilla Rozindo

2014-04-01

172

Fluctuating Asymmetry in elk Cervus elaphus Antlers is Unrelated to Environmental Conditions in the Greater Yellowstone Ecosystem  

Microsoft Academic Search

Fluctuating asymmetry (FA) is a measure of the deviation from perfect bilateral symmetry, and has been used across mammals as a reliable indicator of environmental stress during growth and development. Antler size and symmetry can be an indicator of individual fitness and social rank among ungulates such as the North American elk Cervus elaphus. When environmental conditions are favourable, ungulates

Scott L. Eggeman; Mark Hebblewhite; Julie Cunningham; Ken Hamlin

2009-01-01

173

The interplay between environmental conditions and allee effects during the recovery of stressed zooplankton communities.  

PubMed

Many important ecological phenomena depend on the success or failure of small introduced populations. Several factors are thought to influence the fate of small populations, including resource and habitat availability, dispersal levels, interspecific interactions, mate limitation, and demographic stochasticity. Recent field studies suggest that Allee effects resulting from mate limitation can prevent the reestablishment of sexual zooplankton species following a disturbance. In this study, we explore the interplay between Allee effects and local environmental conditions in determining the population growth and establishment of two acid-sensitive zooplankton species that have been impacted by regional anthropogenic acidification. We conducted a factorial design field experiment to test the impact of pH and initial organism densities on the per capita population growth (r) of the sexual copepod Epischura lacustris and the seasonally parthenogenetic cladoceran Daphnia mendotae. In addition, we conducted computer simulations using r values obtained from our experiments to determine the probability of extinction for small populations of acid-sensitive colonists that are in the process of colonizing recovering lakes. The results of our field experiment demonstrated that local environmental conditions can moderate the impacts of Allee effects for E. lacustris: Populations introduced at low densities had a significantly lower r at pH 6 than at pH 7. In contrast, r did not differ between pH 6 and 7 environments when E. lacustris populations were introduced at high densities. D. mendotae was affected by pH levels, but not by initial organism densities. Results from our population growth simulations indicated that E. lacustris populations introduced at low densities to pH 6 conditions had a higher probability of extinction than those introduced at low densities to a pH 7 environment. Our study indicates that environmental conditions and mate limitation can interact to determine the fate of small populations of sexually reproducing zooplankton species. If a more rapid recovery of acid-damaged zooplankton communities is desired, augmentation of dispersal levels may be needed during the early phases of pH recovery in order to increase the probability of establishment for mate-limited zooplankton species. PMID:22073650

Gray, Derek K; Arnott, Shelley E

2011-10-01

174

[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

2006-01-01

175

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

176

Alterations in phospholipidomic profile in the brain of mouse model of depression induced by chronic unpredictable stress.  

PubMed

Depression is a worldwide disability disease associated with high morbidity and has increased dramatically in the last few years. The differential diagnosis and the definition of an individualized therapy for depression are hampered by the absence of specific biomarkers. The aim of this study was to evaluate the phospholipidomic profile of the brain and myocardium in a mouse model of depression induced by chronic unpredictable stress (CUS). The lipidomic profile was evaluated by thin layer and liquid chromatography and mass spectrometry and lipid oxidation was estimated by FOX II assay. Antioxidant enzyme activity and the oxidized/reduced glutathione (GSH/GSSG) ratio were also evaluated. Results showed that chronic stress affects primarily the lipid profile of the brain, inducing an increase in lipid hydroperoxides, which was not detected in the myocardium. A significant decrease in phosphatidylinositol (PI) and in cardiolipin (CL) relative contents and also oxidation of CL and a significant increase of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were observed in the brain of mice after unpredictable chronic stress conditions. In the myocardium only an increase in PC content was observed. Nevertheless, both organs present a decreased GSH/GSSG ratio when compared to control groups, corroborating the occurrence of oxidative stress. The enzyme activities of catalase (CAT) and superoxide dismutase (SOD) were found to be decreased in the myocardium and increased in the brain, while glutathione reductase (GR) was decreased in the brain. Our results indicate that in a mouse model for studying depression induced by CUS, the modification of the expression of oxidative stress-related enzymes did not prevent lipid oxidation in organs, particularly in the brain. These observations suggest that depression has an impact on the brain lipidome and that further studies are needed to better understand lipids role in depression and to evaluate their potential as future biomarkers. PMID:24814727

Faria, R; Santana, M M; Aveleira, C A; Simões, C; Maciel, E; Melo, T; Santinha, D; Oliveira, M M; Peixoto, F; Domingues, P; Cavadas, C; Domingues, M R M

2014-07-25

177

Multiscale effects of management, environmental conditions, and land use on nitrate leaching in dairy farms.  

PubMed

Nitrate leaching in intensive grassland- and silage maize-based dairy farming systems on sandy soil is a main environmental concern. Here, statistical relationships are presented between management practices and environmental conditions and nitrate concentration in shallow groundwater (0.8 m depth) at farm, field, and point scales in The Netherlands, based on data collected in a participatory approach over a 7-yr period at one experimental and eight pilot commercial dairy farms on sandy soil. Farm milk production ranged from 10 to 24 Mg ha(-1). Soil and hydrological characteristics were derived from surveys and weather conditions from meteorological stations. Statistical analyses were performed with multiple regression models. Mean nitrate concentration at farm scale decreased from 79 mg L(-1) in 1999 to 63 in 2006, with average nitrate concentration in groundwater decreasing under grassland but increasing under maize land over the monitoring period. The effects of management practices on nitrate concentration varied with spatial scale. At farm scale, nitrogen surplus, grazing intensity, and the relative areas of grassland and maize land significantly contributed to explaining the variance in nitrate concentration in groundwater. Mean nitrate concentration was negatively correlated to the concentration of dissolved organic carbon in the shallow groundwater. At field scale, management practices and soil, hydrological, and climatic conditions significantly contributed to explaining the variance in nitrate concentration in groundwater under grassland and maize land. We conclude that, on these intensive dairy farms, additional measures are needed to comply with the European Union water quality standard in groundwater of 50 mg nitrate L(-1). The most promising measures are omitting fertilization of catch crops and reducing fertilization levels of first-year maize in the rotation. PMID:21284299

Oenema, Jouke; Burgers, Saskia; Verloop, Koos; Hooijboer, Arno; Boumans, Leo; ten Berge, Hein

2010-01-01

178

Major methodological constraints to the assessment of environmental status based on the condition of benthic communities  

NASA Astrophysics Data System (ADS)

The Marine Strategy Framework Directive (MSFD) was published in 2008 and requires Member States to take the necessary measures to achieve or maintain good environmental status in aquatic ecosystems by the year of 2020. The MSFD indicates 11 qualitative descriptors for environmental status assessment, including seafloor integrity, using the condition of the benthic community as an assessment indicator. Member States will have to define monitoring programs for each of the MSFD descriptors based on those indicators in order to understand which areas are in a Good Environmental Status and what measures need to be implemented to improve the status of areas that fail to achieve that major objective. Coastal and offshore marine waters are not frequently monitored in Portugal and assessment tools have only been developed very recently with the implementation of the Water Framework Directive (WFD). The lack of historical data and knowledge on the constraints of benthic indicators in coastal areas requires the development of specific studies addressing this issue. The major objective of the current study was to develop and test and experimental design to assess impacts of offshore projects. The experimental design consisted on the seasonal and interannual assessment of benthic invertebrate communities in the area of future implementation of the structures (impact) and two potential control areas 2 km from the impact area. Seasonal benthic samples were collected at nine random locations within the impact and control areas in two consecutive years. Metrics included in the Portuguese benthic assessment tool (P-BAT) were calculated since this multimetric tool was proposed for the assessment of the ecological status in Portuguese coastal areas under the WFD. Results indicated a high taxonomic richness in this coastal area and no significant differences were found between impact and control areas, indicating the feasibility of establishing adequate control areas in marine ecosystems. Nevertheless, significant differences were found between different seasons and different years, showing that the coastal benthic communities important temporal variations. Although those variations did not affect the status assessment based on metrics that considered the ratio between sensitive and tolerant taxa, diversity indices showed different classifications between seasons and years. These results indicate the need for a temporal stratification of the monitoring programs. That might be achieved by setting different thresholds for specific seasons or selecting specific monitoring seasons. It might also require a regular assessment of the environmental conditions that support the identification of outlier years, which monitoring results should be carefully considered.

Medeiros, João Paulo; Pinto, Vanessa; Sá, Erica; Silva, Gilda; Azeda, Carla; Pereira, Tadeu; Quintella, Bernardo; Raposo de Almeida, Pedro; Lino Costa, José; José Costa, Maria; Chainho, Paula

2014-05-01

179

Biosurfactant production under extreme environmental conditions by an efficient microbial consortium, ERCPPI-2.  

PubMed

The biosurfactant production potential of a new microbial consortium of Enterobacter cloacae and Pseudomonas sp. (ERCPPI-2) which was isolated from heavy crude oil-contaminated soil in the south of Iran, has been investigated under extreme environmental conditions. The isolated consortium produces a biosurfactant mixture with excessive oil spreading and emulsification properties. This consortium was able to grow and produce biosurfactant at temperatures up to 70 °C, pressures up to 6000 psia, salinities up to 15% (w/v), and in the pH range 4-10. Besides, the optimum biosurfactant production conditions were found to be 40 °C and 7.0 for the temperature and pH value, respectively. These conditions gave the best biosurfactant production of 1.74 g/1 when the cells were grown on a minimal salt medium containing 1.0% (w/v) olive oil, 1.0% (w/v) sodium nitrate supplemented with 1.39% (w/v) K(2)HPO(4) at 40 °C and 150 rpm after 48 h of incubation. The ERCPPI-2 could reduce surface and interfacial tensions to 31.7 and 0.65 mN/m from the original values of 58.3 and 16.9 mN/m, respectively. The isolated consortium produced biosurfactant using heavy crude oil as the sole source of carbon and emulsified the available heavy crude oil up to E(24)=83.4%. The results of the core holder flooding tests at simulated reservoir conditions demonstrated that the oil recovery efficiency due to the injection of the cell-free biosurfactant solution was 27.2%, and the bacterium injection reduced the final residual oil saturations to below 3% at optimum conditions. PMID:21345657

Darvishi, Parviz; Ayatollahi, Shahab; Mowla, Dariush; Niazi, Ali

2011-06-01

180

Studies on photodegradation of levomepromazine and olanzapine under simulated environmental conditions.  

PubMed

The present study discusses the influence of sunlight on the photostability of levomepromazine (LV) and olanzapine (OLA) hydrochlorides in river water. Four samples of water from different rivers were used in the research. In their course, it turned out that levomepromazine easily underwent photooxidation under simulated environmental conditions, resulting in the generation of its sulphoxide. Olanzapine, on the other hand, appeared to be more resistant to sunlight, as its photodecomposition proceeded slowly, and only one product of its decomposition was detected spectrophotometrically during the process. The photodegradation was analyzed in detail using principal component analysis (PCA) and multivariate curve resolution alternating least squares (MCR-ALS) chemometric methods, and the outcomes verified by HPLC and GC-MS analysis. It can be stated that the rates of the observed processes heavily depended on the chemical composition of the fresh water used in the experiments. PMID:22859061

Karpi?ska, Joanna; Sokó?, Aneta; Bernatowicz, Anna; Szul?cka, Aneta; Kotowska, Urszula

2012-10-01

181

Optimization of mechanical oil spill recovery equipment under variable environmental conditions  

NASA Astrophysics Data System (ADS)

Oil spills in marine environments may cause significant damage to marine and coastal ecosystems if not recovered quickly and efficiently. Although mechanical recovery is the most commonly used oil spill response technique, it can be very time consuming and expensive when employed at a large scale due, to its low recovery rates. The goal of this work was to optimize mechanical oil spill recovery for various environmental conditions by analyzing the recovery process and identifying parameters with the most significant impact on the recovery efficiency. As a result of this work, laboratory equipment and procedures tailored to the study of oil spill recovery at small scale were developed. A number of materials and surface patterns that can increase the adhesion skimmer recovery efficiency up to three times were identified and tested in a full scale oil spill recovery study.

Broje, Viktoria A.

182

Visible/near-infrared hyperspectral sensing of solids under controlled environmental conditions  

NASA Astrophysics Data System (ADS)

We describe the use of a wind tunnel for conducting controlled passive hyperspectral imaging experiments. In recent years, passive hyperspectral detection of solids, minerals and ores has emerged as a very useful technique, for example for classifying land types, mineral deposits, and agricultural practices. Such techniques are also 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 whereby certain environmental parameters can be controlled such as lighting, humidity, temperature, aerosol and obscurant burdens. By selecting the appropriate fore-optics and sample size, one can conduct meaningful experiments under controlled conditions at relatively low cost when compared to typical field deployments. 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, Bradley G.; Johnson, Timothy J.

2011-05-01

183

Food for thought: Conditions for discourse reflection in the light of environmental assessment  

SciTech Connect

People tend to take notice of what is happening around them selectively. Discourses-frames through which actors give meaning to aspects of the world-act as built-in filters that distinguish relevant from irrelevant data. Use of knowledge generated by environmental assessments (EAs) in decision-making may be understood from this perspective. Environmental knowledge that is inconsistent with dominant discourses runs the risk of being ignored. Discourses on the value of EA as a tool for decision-making may have a similar effect. Stimulating decision-makers and stakeholders to critically reflect on and reconsider their discourses in the light of EAs-also known as frame reflection or policy learning-may enhance the probability that these assessments and the knowledge that they generate impact upon decision-making. Up to now little has been written about how discourse reflection in the context of EA can be promoted. Valuable inputs are fragmented over different bodies of literature. In this paper we draw from these bodies to identify favourable conditions for discourse reflection.

Runhaar, Hens, E-mail: h.runhaar@geo.uu.n [Copernicus Institute for Sustainable Development and Innovation, Utrecht University, P.O. Box 80, 115, 3508 TC Utrecht (Netherlands); Runhaar, Piety R., E-mail: p.r.honnef-runhaar@gw.utwente.n [Organisational Psychology and Human Resource Development, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Oegema, Tammo, E-mail: tammo.oegema@imsa.n [IMSA Amsterdam, Prins Hendriklaan 15, 1075 AX Amsterdam (Netherlands)

2010-11-15

184

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

Microsoft Academic Search

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

Carol C Baskin; Jerry M Baskin; Edward W Chester

2004-01-01

185

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

186

Exertional Heat Illness and Environmental Conditions During a Single Football Season in the Southeast  

PubMed Central

Context: Recommendations for heat illness prevention provided by sports medicine associations do not always account for sex differences, specific age populations, regional environmental conditions, equipment worn during activity, or the athlete's size or preexisting level of fitness. Objective: To evaluate the rate of exertional heat illness (EHI) among collegiate football athletes and to monitor environmental conditions during American football practice for a 3-month period. Design: Epidemiologic study in which we reviewed the occurrence rates of EHI and wet bulb globe temperature readings during a 3-month period of American collegiate football practice sessions. Setting: Five universities in the southeastern region of the United States. Patients or Other Participants: Collegiate football players at the 5 universities. Main Outcome Measure(s): Wet bulb globe temperatures were recorded from August through October 2003, at the beginning, middle, and end of each practice session. The EHIs were identified and recorded, and athlete-exposures (AEs) were calculated. Results: A total of 139 EHIs and 33?196 AEs were reported (EHI rate = 4.19/1000 AEs). The highest incidence of EHIs was in August (88%, EHI rate = 8.95/1000 AEs) and consisted of 70% heat cramps (6.13/1000 AEs), 23% heat exhaustion (2.06/ 1000 AEs), and 7% heat syncope (0.58/1000 AEs). No cases of heat stroke or hyponatremia were identified. The highest risk of EHI occurred during the first 3 weeks of the study; mean wet bulb globe temperature declined significantly as the study continued ( P < .001). Temperatures in the final 5 weeks of the study were significantly cooler than in the first 5 weeks ( P < .05). Conclusions: Heat cramps were the most common EHI and occurred most often during the first 3 weeks of practice. Athletic trainers should take all necessary preventive measures to reduce the risk of EHI. PMID:17043703

Cooper, Earl R; Ferrara, Michael S; Broglio, Steven P

2006-01-01

187

Environmental conditions affect transcription of the pectinase genes of Erwinia chrysanthemi 3937.  

PubMed Central

To depolymerize plant pectin, the phytopathogenic enterobacterium Erwinia chrysanthemi produces a series of enzymes which include a pectin-methyl-esterase encoded by the pem gene and five isoenzymes of pectate lyases encoded by the five genes pelA, pelB, pelC, pelD, and pelE. We have constructed transcriptional fusions between the pectinase gene promoters and the uidA gene, encoding beta-glucuronidase, to study the regulation of these E. chrysanthemi pectinase genes individually. The transcription of the pectinase genes is dependent on many environmental conditions. All the fusions were induced by pectic catabolic products and responded, to different degrees, to growth phase, catabolite repression, temperature, and nitrogen starvation. Transcription of pelA, pelD, and pelE was also increased in anaerobic growth conditions. High osmolarity of the culture medium increased expression of pelE but decreased that of pelD; the other pectinase genes were not affected. The level of expression of each gene was different. Transcription of pelA was very low under all growth conditions. The expression of the pelB, pelC, and pem genes was intermediate. The pelE gene had a high basal level of expression. Expression of pelD was generally the most affected by changes in culture conditions and showed a low basal level but very high induced levels. These differences in the expression of the pectinase genes of E. chrysanthemi 3937 presumably reflect their role during infection of plants, because the degradation of pectic polymers of the plant cell walls is the main determinant of tissue maceration caused by soft rot erwiniae. PMID:1447147

Hugouvieux-Cotte-Pattat, N; Dominguez, H; Robert-Baudouy, J

1992-01-01

188

Energy policy for integrating the building environmental performance model of an air conditioned building in a subtropical climate  

Microsoft Academic Search

For an air conditioned building, the major electricity consumption is by the heating, and air conditioning (HVAC) system. As energy saving strategies may be in conflict with the criteria of indoor air quality and thermal comfort, a concept of the building environmental performance model (BEPM) has been developed to optimize energy consumption in HVAC systems without any deterioration of the

K. W. Mui

2006-01-01

189

Purdue AgronomyPurdue AgronomyCROP, SOIL, AND ENVIRONMENTAL SCIENCES Septic Systems in Flooded and Wet Soil Conditions  

E-print Network

and Wet Soil Conditions Brad Lee and Don Jones Department of Agronomy and Department of Agricultural Systems in Flooded and Wet Soil Conditions--HENV-10-W How to Prepare for a Flood If flooding appearsPurdue AgronomyPurdue AgronomyCROP, SOIL, AND ENVIRONMENTAL SCIENCES Septic Systems in Flooded

Holland, Jeffrey

190

Past trends and future scenarios for environmental conditions favoring the accumulation of paralytic shellfish toxins in Puget Sound shellfish  

Microsoft Academic Search

The risk of harmful algal blooms (HABs) of the dinoflagellate Alexandrium catenella in Puget Sound, Washington State, can be assessed by identifying and predicting climate and environmental conditions that are favorable for bloom development and the accumulation of paralytic shellfish toxins (PSTs) in shellfish. When these favorable conditions occur in combination, a harmful algal bloom window of opportunity (HAB-WOO) exists

Stephanie K. Moore; Nathan J. Mantua; Eric P. Salathé

2011-01-01

191

Migration path annotation: cross-continental study of migration-flight response to environmental conditions.  

PubMed

Understanding the movements of animals is pivotal for understanding their ecology and predicting their survival in the face of rapid global changes to climate, land use, and habitats, thus facilitating more effective habitat management. Migration by flying animals is an extreme form of movement that may be especially influenced by weather. With satellite telemetry studies, and the growing availability of information about the Earth's weather and land surface conditions, many data are collected that can advance our understanding about the mechanisms that shape migrations. We present the track annotation approach for movement data analysis using information about weather from the North American Reanalysis data set, a publicly available, regional, high-resolution model-observation hybrid product, and about topography, from a publicly available high-resolution digital elevation model (DEM). As a case study, we present the analysis of the response to environmental conditions in three contrasting populations of Turkey Vultures (Cathartes aura) across North America, tracked with a three-dimensional GPS-based sensor. Two populations in the east and west coasts of the United States responded similarly to weather, indicating use of both slope and thermal soaring. Continental-interior, "Plains populations," exhibited a different migratory pattern primarily indicative of thermal soaring. These differences help us understand the constraints and behaviors of soaring migrants. The track annotation approach allowed large-scale comparative study of movement in an important migratory species, and will enable similar studies at local to global scales. PMID:21939059

Mandel, James T; Bohrer, Gil; Winkler, David W; Barber, David R; Houston, C Stuart; Bildstein, Keith L

2011-09-01

192

The Effects of Varying Environmental Conditions on the Emission Spectra of Meteorites  

NASA Astrophysics Data System (ADS)

With NASA's OSIRIS-REx mission due to launch to asteroid 101955 Bennu (previously known as 1999 RQ36) in 2016, preparations are well underway [4]. Once there, the OTES (OSIRIS-Rex Thermal Emission Spectrometer) instrument will map the asteroid's surface to derive thermal and compositional properties [4], by comparing spectra to those of known samples measured in the laboratory. Previous studies have shown that samples can exhibit differen ces in emission spectra due to composition, grain size and the environmental conditions in which they are measured [3,5,7], however the magnitude of these variations for asteroidal material require more study. The aim of this work is to determine whether laboratory samples need to be measured in a thermal environment like that on the asteroid's surface for correct interpretation of returning data from OTES: to do this, the Lunar Environment Chamber in the Planetary Spectroscopy Facility at Oxford University [7] was used to simulate the expected conditions on Bennu while a selection of ground meteorite samples were measured.

Thomas, I. R.; Bowles, N. E.; Connolly, H. C.; Kilgore, M.; Lauretta, D. S.

2013-09-01

193

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

194

Cold-water coral growth under extreme environmental conditions, the Cape Lookout area, NW Atlantic  

NASA Astrophysics Data System (ADS)

The Cape Lookout cold-water coral area off the coast of North Carolina forms the shallowest and northernmost cold-water coral mound area on the Blake Plateau in the NW Atlantic. Cold-water coral habitats near Cape Lookout are occasionally bathed in the Gulf Stream, which is characterised by oligotrophic warm water and strong surface currents. Here, we present the first insights into the mound distribution and morphology, sedimentary environment and coral cover and near-bed environmental conditions as recorded by bottom landers from this coral area. The mounds occur between 320 and 550 m water depth and are characterised by high acoustic backscatter indicating the presence of hard structure. Three distinct mound morphologies were observed: (1) a mound with a flattened top at 320 m, (2) multi-summited mounds with a teardrop shape in the middle part of the area and (3) a single mound at 540 m water depth. Echosounder profiles show the presence of a strong reflector underneath all mound structures that forms the base of the mounds. This reflector cropped out at the downstream side of the single mound and consists of carbonate slabs. Video analysis revealed that all mounds are covered by Lophelia pertusa and that living colonies only occur close to the summits of the SSW side of the mounds, which is the side that faces the strongest currents. Off-mound areas were characterised by low backscatter and sediment ripples, indicating the presence of relatively strong bottom currents. Two bottom landers were deployed amidst the coral mounds between December 2009 and May 2010. Both landers recorded prominent events, characterised by large fluctuations in environmental conditions near the seabed as well as in the overlying water column. The period between December and April was characterised by several events of increasing temperature and salinity, coinciding with increased flow and near-bed acoustic backscatter. During these events temperature fluctuated by up to 9 °C within a day, which is the largest temperature variability as measured so far in a cold-water coral habitat. Warm events, related to Gulf Stream meanders, had the duration of roughly 1 week and the current during these events was directed to the NNE. The consequences of such events must be significant given the strong effects of temperature on the metabolism of cold-water corals. Furthermore, elevated acoustic backscatter values and high mass fluxes were also recorded during these events, indicating a second stressor that may affect the corals. The abrasive nature of sand in combination with strong currents might sand blast the corals. We conclude that cold-water corals near Cape Lookout live under extreme conditions that limit mound growth at present.

Mienis, F.; Duineveld, G. C. A.; Davies, A. J.; Lavaleye, M. M. S.; Ross, S. W.; Seim, H.; Bane, J.; van Haren, H.; Bergman, M. J. N.; de Haas, H.; Brooke, S.; van Weering, T. C. E.

2014-05-01

195

Exploring the relationship between vegetation spectra and eco-geo-environmental conditions in karst region, Southwest China.  

PubMed

Remote sensing of local environmental conditions is not accessible if substrates are covered with vegetation. This study explored the relationship between vegetation spectra and karst eco-geo-environmental conditions. Hyperspectral remote sensing techniques showed that there were significant differences between spectral features of vegetation mainly distributed in karst and non-karst regions, and combination of 1,300- to 2,500-nm reflectance and 400- to 680-nm first-derivative spectra could delineate karst and non-karst vegetation groups. Canonical correspondence analysis (CCA) successfully assessed to what extent the variation of vegetation spectral features can be explained by associated eco-geo-environmental variables, and it was found that soil moisture and calcium carbonate contents had the most significant effects on vegetation spectral features in karst region. Our study indicates that vegetation spectra is tightly linked to eco-geo-environmental conditions and CCA is an effective means of studying the relationship between vegetation spectral features and eco-geo-environmental variables. Employing a combination of spectral and spatial analysis, it is anticipated that hyperspectral imagery can be used in interpreting or mapping eco-geo-environmental conditions covered with vegetation in karst region. PMID:19089594

Yue, Yuemin; Wang, Kelin; Zhang, Bing; Chen, Zhengchao; Jiao, Quanjun; Liu, Bo; Chen, Hongsong

2010-01-01

196

Biofilm formation and exopolysaccharide (EPS) production by Cronobacter sakazakii depending on environmental conditions.  

PubMed

Biofilm matrices are formed largely of extracellular polymeric substance (EPS). This study was conducted to investigate biofilm formation and EPS production by Cronobacter sakazakii under various conditions (media, nutrition, and relative humidity (RH)) by quantification of EPS and cell populations, Field Emission Scanning Electron Microscope (FE-SEM), and colony observation. Various agar media conditions (TSA without dextrose (W/D), M9 minimum salt medium (MSM) agar, and M9 MSM agar with 3% glucose, 3% NaCl, 3% Tween 80, 3% sucrose, and adjusted to pH 5 with HCl) were prepared. C. sakazakii biofilm formed on the surface of stainless steel coupons (SSCs) immersed in TSB W/D and M9 MSM with or without 0, 1, 3, and 5% sucrose and subsequently exposed to various RH levels (23, 43, 68, 85, and 100%). EPS production by C. sakazakii on TSA W/D was significantly higher than that on other media after 1 and 2 days. However, C. sakazakii ATCC 12868 produced the highest levels of EPS (209.18 ± 16.13 and 207.22 ± 4.14 ?g/mL after 1 and 2 days, respectively) on M9 MSM agar with 3% sucrose. Regarding C. sakazakii ATCC 12868 biofilm formed on the surface of SSCs immersed in M9 MSM with 0, 1, 3, and 5% sucrose and subsequently exposed to various RHs, populations were significantly different among the various RHs and sucrose concentrations, and EPS production was significantly higher (4.69 mg/L) compared to other sucrose concentrations (0%:0.71 mg/L and 1%:0.98 mg/L), except for M9 MSM with 3% sucrose (2.97 mg/L) (P ? 0.05). From these results, biofilm formation and EPS production by C. sakazakii differed depending on the nutrient or environmental conditions provided to the cells. PMID:23498180

Jung, Jin-Ho; Choi, Na-Young; Lee, Sun-Young

2013-05-01

197

Relationships between Traumatic Symptoms and Environmental Damage Conditions among Children 8 Months after the 2011 Japan Earthquake and Tsunami  

PubMed Central

Background To evaluate relationships between traumatic symptoms and environmental damage conditions among children who survived the 2011 Great East Japan Earthquake and Tsunami. Methods The subjects were 12,524 children in kindergartens, elementary schools, and junior high schools in Ishinomaki City, Miyagi Prefecture, Japan. The Post Traumatic Stress Symptoms for Children 15 items (PTSSC-15), a self-completion questionnaire on traumatic symptoms, was distributed to the children and a questionnaire regarding environmental damage conditions affecting the children was distributed to their teachers. Of 12,524 questionnaires distributed, an effective response was obtained from 11,692 (93.3%). Results The PTSSC-15 score was significantly higher in females than in males among 4th to 6th grade students in elementary schools and among junior high school students. In terms of traumatic symptoms and environmental damage conditions, with the exception of kindergartners, children who had their houses damaged or experienced separation from family members had a significantly higher PTSSC-15 score than children who did not experience environmental damage. Except for kindergartners and 4th- to 6th-grade elementary school students, children who experienced evacuation had a significantly higher PTSSC-15 score. Conclusions This study demonstrated relationships between traumatic symptoms and environmental damage conditions in children who had suffered from the disaster. Factors examined in studying the relationship between environmental damage conditions and traumatic symptoms were gender, age, house damage, evacuation experience, and bereavement experience. It was critical not only to examine the traumatic symptoms of the children but also to collect accurate information about environmental damage conditions. PMID:23209817

Usami, Masahide; Iwadare, Yoshitaka; Kodaira, Masaki; Watanabe, Kyota; Aoki, Momoko; Katsumi, Chiaki; Matsuda, Kumi; Makino, Kazunori; Iijima, Sonoko; Harada, Maiko; Tanaka, Hiromi; Sasaki, Yoshinori; Tanaka, Tetsuya; Ushijima, Hirokage; Saito, Kazuhiko

2012-01-01

198

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. PMID:23891687

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

2013-01-01

199

Automated ambulatory assessment of cognitive performance, environmental conditions, and motor activity during military operations  

NASA Astrophysics Data System (ADS)

Until recently scientists had limited opportunities to study human cognitive performance in non-laboratory, fully ambulatory situations. Recently, advances in technology have made it possible to extend behavioral assessment to the field environment. One of the first devices to measure human behavior in the field was the wrist-worn actigraph. This device, now widely employed, can acquire minute-by-minute information on an individual"s level of motor activity. Actigraphs can, with reasonable accuracy, distinguish sleep from waking, the most critical and basic aspect of human behavior. However, rapid technologic advances have provided the opportunity to collect much more information from fully ambulatory humans. Our laboratory has developed a series of wrist-worn devices, which are not much larger then a watch, which can assess simple and choice reaction time, vigilance and memory. In addition, the devices can concurrently assess motor activity with much greater temporal resolution then the standard actigraph. Furthermore, they continuously monitor multiple environmental variables including temperature, humidity, sound and light. We have employed these monitors during training and simulated military operations to collect information that would typically be unavailable under such circumstances. In this paper we will describe various versions of the vigilance monitor and how each successive version extended the capabilities of the device. Samples of data from several studies are presented, included studies conducted in harsh field environments during simulated infantry assaults, a Marine Corps Officer training course and mechanized infantry (Stryker) operations. The monitors have been useful for documenting environmental conditions experienced by wearers, studying patterns of sleep and activity and examining the effects of nutritional manipulations on warfighter performance.

Lieberman, Harris R.; Kramer, F. Matthew; Montain, Scott J.; Niro, Philip; Young, Andrew J.

2005-05-01

200

Environmental conditions predict helminth prevalence in red foxes in Western Australia?  

PubMed Central

Red foxes (Vulpes vulpes) are the most common and widely distributed wild carnivore worldwide. These predators harbour a wide range of parasites, many of which may have important conservation, agricultural and zoonotic repercussions. This project investigated the occurrence of helminth parasites from the intestines of 147 red foxes across 14 sampling localities of southwest Western Australia. Helminth parasites were detected in 58% of fox intestines: Dipylidium caninum (27.7% of foxes), Uncinaria stenocephala (18.2%), Toxocara canis (14.9%), Spirometra erinaceieuropaei (5.4%), Toxascaris leonina (4.7%), Taenia serialis (1.4%), Taenia hydatigena (0.7%), unidentified Taenia spp. (4.1%), Brachylaima cribbi (0.7%), Plagiorchis maculosus (0.7%) and an Acanthocephalan; family Centrorhynchidae (2.1%). Importantly, two cestodes of agricultural significance, Echinococcus granulosus and Taenia ovis, were not detected in red foxes in this study, despite the presence of suitable intermediate hosts in the diets of these animals. Parasite richness varied from 1–3 species per host, with average parasite number varying from 1–39 worms (across all helminth species). Regression analyses indicated that the presence of four helminth parasites was related to various environmental factors. The presence of S. erinaceieuropaei (p < 0.001), T. leonina (p < 0.01) and U. stenocephala (p < 0.01) was positively associated with average relative humidity which may affect the longevity of infective stages in the environment. The presence of S. erinaceieuropaei and U. stenocephala (p < 0.001) was positively associated with 5-y-average minimum temperature which could reflect poor survival of infective stages through cold winter conditions. The presence of T. canis and U. stenocephala (p < 0.001) was positively associated with the percentage cover of native vegetation at each sampling location, which is likely to reflect transmission from native prey species acting as paratenic hosts. These data identify environmental factors affecting transmission and potential distribution of each parasite taxon, and provide important information increasing our understanding of the potential effects of environmental change on parasite ecology. PMID:24533331

Dybing, Narelle A.; Fleming, Patricia A.; Adams, Peter J.

2013-01-01

201

Environmental conditions predict helminth prevalence in red foxes in Western Australia.  

PubMed

Red foxes (Vulpes vulpes) are the most common and widely distributed wild carnivore worldwide. These predators harbour a wide range of parasites, many of which may have important conservation, agricultural and zoonotic repercussions. This project investigated the occurrence of helminth parasites from the intestines of 147 red foxes across 14 sampling localities of southwest Western Australia. Helminth parasites were detected in 58% of fox intestines: Dipylidium caninum (27.7% of foxes), Uncinaria stenocephala (18.2%), Toxocara canis (14.9%), Spirometra erinaceieuropaei (5.4%), Toxascaris leonina (4.7%), Taenia serialis (1.4%), Taenia hydatigena (0.7%), unidentified Taenia spp. (4.1%), Brachylaima cribbi (0.7%), Plagiorchis maculosus (0.7%) and an Acanthocephalan; family Centrorhynchidae (2.1%). Importantly, two cestodes of agricultural significance, Echinococcus granulosus and Taenia ovis, were not detected in red foxes in this study, despite the presence of suitable intermediate hosts in the diets of these animals. Parasite richness varied from 1-3 species per host, with average parasite number varying from 1-39 worms (across all helminth species). Regression analyses indicated that the presence of four helminth parasites was related to various environmental factors. The presence of S. erinaceieuropaei (p < 0.001), T. leonina (p < 0.01) and U. stenocephala (p < 0.01) was positively associated with average relative humidity which may affect the longevity of infective stages in the environment. The presence of S. erinaceieuropaei and U. stenocephala (p < 0.001) was positively associated with 5-y-average minimum temperature which could reflect poor survival of infective stages through cold winter conditions. The presence of T. canis and U. stenocephala (p < 0.001) was positively associated with the percentage cover of native vegetation at each sampling location, which is likely to reflect transmission from native prey species acting as paratenic hosts. These data identify environmental factors affecting transmission and potential distribution of each parasite taxon, and provide important information increasing our understanding of the potential effects of environmental change on parasite ecology. PMID:24533331

Dybing, Narelle A; Fleming, Patricia A; Adams, Peter J

2013-12-01

202

Holocene environmental conditions in South Georgia - a multi-proxy study on a coastal marine record  

NASA Astrophysics Data System (ADS)

The Holocene environmental history of the sub-Antarctic island of South Georgia so far has been reconstructed from lake sediments, peat records and geomorphological observations. The data available indicate a postglacial ice retreat, which reached the coastal areas around the early Holocene. Climate reconstructions for the Holocene, on the other hand, provide a more complex picture, which may partly result from the influence of local effects. We present preliminary results of a multi-proxy study on a sediment core recovered in early 2013 from a coastal marine inlet (Little Jason Lagoon) in Cumberland West Bay. The results include elemental data (high resolution XRF-scans, total organic carbon (TOC), nitrogen, and sulphur, lipid biomarkers, and macrofossil data. The sediment core comprises a c. 11m long sequence, which contains a complete record of postglacial sedimentation in the inlet. Its base is formed by a diamicton, indicating a former glaciation of the site, which is overlain by well-stratified sediments passing over into more massive muds in the upper past. A radiocarbon age from the organic-rich sediments above the diamicton provides a first estimate of 9700 14C years BP for a minimum age of ice retreat. We use the elemental data to infer changes in clastic input (e.g., K/Ti ratios), productivity (TOC) and water salinity (Cl counts) in the course of the Holocene. While Little Jason Lagoon has a connection to the sea today (sill depth c. 1 m), a decrease in Cl counts downcore points to fresher conditions in the early part of the record. This could be an indicator for changing relative sea level and/or changes in the amounts of freshwater inflow from the catchment. Macroscopic plant remains and lipid biomarkers (n-alkanes, n-fatty acids and sterols) provide information on the terrestrial vegetation in the catchment and its changes through time as well as on the influence of marine conditions in the lagoon. We suggest that the record from Little Jason Lagoon provides an important link between terrestrial and marine archives of Holocene environmental change in South Georgia.

Berg, Sonja; Jivcov, Sandra; Groten, Sonja; Viehberg, Finn; Rethemeyer, Janet; Melles, Martin

2014-05-01

203

Changes in mineral soil biogeochemical cycling and environmental conditions following tree harvest in the Northeast  

NASA Astrophysics Data System (ADS)

In the northeastern United States, reductions in carbon dioxide emissions have been attempted by using local wood as a renewable alternative to oil. Although woody biomass products are readily available, recent findings suggest that forest disturbance may cause release of carbon from the deeper mineral soil. Worldwide, deep soils sequester more than half of soil carbon, making it critical in the global carbon cycle; however, most studies on the effect of harvesting have focused on the organic soil horizon. Our research aimed to uncover changes in biogeochemistry and environmental conditions in deeper, mineral soil after clear cutting forests. We quantified post-harvest mineral soil carbon pools through a regional study. We utilized stands of different ages to measure the recovery of soil carbon over time since harvest. Stands included in this study were cut approximately 5, 12, 25, 50, or 120 ybp, in order to identify changes in soil carbon over time since harvest. We sampled harvested stands in six research or protected forests across New York, New Hampshire, Massachusetts, and Vermont. Soil samples were collected to a depth of 60 cm below the surface of the mineral soil using a gas-powered augur and 9.5 cm diameter drill bit. Soil samples were analyzed at Dartmouth College. In order to understand specific changes in mineral soil carbon dynamics following harvest, measurements of carbon fluxes, such as soil respiration and DOC transport were conducted at five different-aged stands at Bartlett Experimental Forest, NH. While parameters that may influence carbon storage—such as pH, clay content, tree cover and elevation— did not vary across the different-aged stands in each forest, carbon pools did vary over time. We found changes in carbon pools in at least three experimental forests across the northeast. At Bartlett Experimental Forest, we found a gradual decline in mineral soil carbon storage from between 85-87 Mg ha-1 in 120 year old and primary forest stands to a minimum of 53 Mg ha-1 in the 75 year old stand. In our carbon flux measurements, we observed higher DOC concentrations in lysimeter samples collected at 30 cm at 12 years after harvest. We have also documented consistently higher soil temperatures across summer months at 50 cm below the mineral soil in the recently clear-cut site at Bartlett Experimental Forest. These changes in biogeochemical and environmental conditions suggest that forest clearing does affect mineral soil, and our findings may help identify a mechanism to explain the observed carbon loss from soils in clear-cut forests.

Vario, C.; Friedland, A.

2012-12-01

204

Changes of Enzyme Activities and Compositions of Abnormal Fruiting Bodies Grown under Artificial Environmental Conditions in Pleurotus ostreatus  

PubMed Central

This study investigated the biochemical changes of abnormal fruiting bodies grown under artificial environmental conditions in P. ostreatus. Abnormal mushroom growth during cultivation damages the production of good quality mushroom. This study showed that different environmental conditions produced morphological changes in the fruiting bodies of P. ostreatus. The fruiting bodies with morphological changes were collected and examined for differences in biochemical properties, enzyme activities, and carbohydrates composition. The enzyme activities assay showed that glucanase and chitinase activities decreased when the temperature was below or above the optimum cultivation temperature for P. ostreatus. The biochemical compositions of the abnormal mushroom were significantly different from the normal fruiting bodies. It was suggested that the changes in the biochemical composition of abnormal mushroom were caused by the unfavorable environmental conditions during mushroom cultivation. PMID:24049471

Cho, Soo Muk; June, Chang Sung; Weon, Hang Yeon; Park, Jeong Sik; Choi, Sun Gyu; Cheong, Jong Chun; Sung, Jae Mo

2005-01-01

205

Environmental Conditioning of Skeletal Anomalies Typology and Frequency in Gilthead Seabream (Sparus aurata L., 1758) Juveniles  

PubMed Central

In this paper, 981 reared juveniles of gilthead seabream (Sparus aurata) were analysed, 721 of which were from a commercial hatchery located in Northern Italy (Venice, Italy) and 260 from the Hellenic Center for Marine Research (Crete, Greece). These individuals were from 4 different egg batches, for a total of 10 different lots. Each egg batch was split into two lots after hatching, and reared with two different methodologies: intensive and semi-intensive. All fish were subjected to processing for skeletal anomaly and meristic count analysis. The aims involved: (1) quantitatively and qualitatively analyzing whether differences in skeletal elements arise between siblings and, if so, what they are; (2) investigating if any skeletal bone tissue/ossification is specifically affected by changing environmental rearing conditions; and (3) contributing to the identification of the best practices for gilthead seabream larval rearing in order to lower the deformity rates, without selections. The results obtained in this study highlighted that: i) in all the semi-intensive lots, the bones having intramembranous ossification showed a consistently lower incidence of anomalies; ii) the same clear pattern was not observed in the skeletal elements whose ossification process requires a cartilaginous precursor. It is thus possible to ameliorate the morphological quality (by reducing the incidence of severe skeletal anomalies and the variability in meristic counts of dermal bones) of reared seabream juveniles by lowering the stocking densities (maximum 16 larvae/L) and increasing the volume of the hatchery rearing tanks (minimum 40 m3). Feeding larvae with a wide variety of live (wild) preys seems further to improve juvenile skeletal quality. Additionally, analysis of the morphological quality of juveniles reared under two different semi-intensive conditions, Mesocosm and Large Volumes, highlighted a somewhat greater capacity of Large Volumes to significantly augment the gap with siblings reared in intensive (conventional) modality. PMID:23409031

Prestinicola, Loredana; Boglione, Clara; Makridis, Pavlos; Spano, Attilio; Rimatori, Valentina; Palamara, Elisa; Scardi, Michele; Cataudella, Stefano

2013-01-01

206

Variation of saponin contents and physiological status in Quillaja saponaria under different environmental conditions.  

PubMed

Quillaja saponaria (Quillay), an evergreen tree found in Chile, is one of the main sources of saponins. Quillaja saponins have hypocholesterolaemic, anticarcinogenic, antioxidant and pesticidal properties, and are used as adjuvants for vaccines. Samples of Quillay growing at three zones in O'Higgins Region, Chile (Coastal, Central and Mountain zones) were analyzed for content of saponins and physiological status. The results revealed differences in the content of saponins depending on the zone of sample collection. The highest contents were found in samples from the Mountain zone, where the highest saponin contents were accompanied by the lowest foliar nitrogen contents, the highest antioxidant activity and the highest carotenoid contents. The results suggest a physiological and adaptive mechanism of saponins in plants to survive under unfavourable environmental conditions. The results have important implications for a theoretical basis for the design of a reasonable harvest, to avoid the cost of poor quality material, and also to provide a sustainable use and conservation of this important species. Further research on the effects of stress will improve our understanding of the saponins production and their physiological functions in plants, whereas they have generally been studied for their biological and chemical applications. PMID:24555275

Grandón, Angélica S; Espinosa, B Miguel; Ríos, Darcy L; Sánchez, O Manuel; Sáez, C Katia; Hernández, S Víctor; Becerra, A José

2013-12-01

207

Environmental conditions in near-wall plasmas generated by impact of energetic particle fluxes  

NASA Astrophysics Data System (ADS)

Directional flows of energetic ions produced by laser-exploded foils were used to investigate transient phenomena accompanying the plasma interaction with surfaces of solid targets (walls). In experiments carried out on the iodine laser system PALS, the formation of energetic plasma jets from burn-through foils of Al and Ta was optimized using the three-frame interferometry and applied to a design of alternate experimental configurations. The interaction of the directional plasma flows with secondary targets was studied via X-ray imaging, optical and high-resolution X-ray spectroscopy. The environmental conditions in near-wall plasmas created at surfaces of plasma-exposed solids, in particular the velocity distribution of impinging and back-scattered ions, were determined via analysis of the observed spatially-resolved spectra of Al Ly? and He? groups. The validity of the ion velocity gradients derived from the Doppler effect induced shifts and splitting of the spectral lines was supported by theoretical modeling based on a combination of hydrodynamic, atomic and collisional-radiative codes.

Renner, O.; Šmíd, M.; Burian, T.; Juha, L.; Krása, J.; Krouský, E.; Matulková, I.; Skála, J.; Velyhan, A.; Liska, R.; Velechovský, J.; Pisarczyk, T.; Chodukowski, T.; Larroche, O.; Ullschmied, J.

2013-09-01

208

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. PMID:23029242

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

2012-01-01

209

Interactions between clay portions with various contacts and subjected to specific environmental conditions  

NASA Astrophysics Data System (ADS)

So far clays have always been considered, both experimentally and theoretically, as ideally flat and under arbitrary orientations. The goal here is to shed light on the different cases of possible contact between portions of clay, which will be subject to peculiar conditions of temperature and pressure. To this end, molecular dynamics study has been performed to investigate the evolution of nonparallel hydrated Wyoming-type Na-montmorillonite. In the present work, we study two clay structures containing two then three nonparallel portions. The contact manners between each other are considered as point and/or edge. We show that under the effect of environmental constraints, the dihedral angle of the horizontal and inclined portions tend to shrink; at the same time, the clay layers of inclined portions have a tendency to rotate. Due to this rotation, the contact of point can be considered as the evolution of the contact of edge. With the presence of water, the layers of inclined clay portions turn in different ways. The temperature effect is negligible, but the pressure plays an important role on the behaviour of clay layers.

Zheng, Y.; Zaoui, A.; Pasteau, A.

2014-02-01

210

Environmental risk assessment of GE plants under low-exposure conditions.  

PubMed

The requirement for environmental risk assessment (ERA) of genetically engineered (GE) plants prior to large scale or commercial introduction into the environment is well established in national laws and regulations, as well as in international agreements. Since the first introductions of GE plants in commercial agriculture in the 1990s, a nearly universal paradigm has emerged for conducting these assessments based on a few guiding principles. These include the concept of case-by-case assessment, the use of comparative assessments, and a focus of the ERA on characteristics of the plant, the introduced trait, and the receiving environment as well as the intended use. In practice, however, ERAs for GE plants have frequently focused on achieving highly detailed characterizations of potential hazards at the expense of consideration of the relevant levels of exposure. This emphasis on exhaustive hazard characterization can lead to great difficulties when applied to ERA for GE plants under low-exposure conditions. This paper presents some relevant considerations for conducting an ERA for a GE plant in a low-exposure scenario in the context of the generalized ERA paradigm, building on discussions and case studies presented during a session at ISBGMO 12. PMID:24178711

Roberts, Andrew; Devos, Yann; Raybould, Alan; Bigelow, Patrick; Gray, Alan

2014-12-01

211

Dependence of Cumulus Anvil Radiative Properties on Environmental Conditions in the Tropical West Pacific  

NASA Technical Reports Server (NTRS)

Areally extensive, optically thick anvil clouds associated with mesoscale convective clusters dominate the shortwave cloud forcing in the tropics and provide longwave forcing comparable to that of thin cirrus. Changes in the cover and optical thickness of tropical anvils as climate warms can regulate the sign of cloud feedback. As a prelude to the study of MMCR data from the ARM TWP sites, we analyze ISCCP-derived radiative characteristics of anvils observed in the tropical west Pacific during the TOGA-COARE IOP. Anvils with radius greater than 100 km were identified and tracked from inception to decay using the Machado-Rossow algorithm. Corresponding environmental conditions just prior to the start of the convectove event were diagnosed using the Lin-Johnson objective analysis product. Small clusters (100-200 km radius) are observed to have a broad range of optical thicknesses (10-50), while intermediate optical thickness clusters are observed to range in size from 100 km to almost 1000 km. Large-size clusters appear to be favored by strong pre-storm large scale upward motion throughout the troposphere, moist low-to-midlevel relative humidities, environments with slightly higher CAPE than those for smaller clusters, and strong front-to-rear flow. Optically thick anvils are favored in situations of strong low-level moisture convergence and strong upper-level shear.

Ye, B.; DelGenio, A. D.

1999-01-01

212

Sensitivity of Latent Heating Profiles to Environmental Conditions: Implications for TRMM and Climate Research  

NASA Technical Reports Server (NTRS)

The Tropical Rainfall Measuring Mission (TRMM) as a part of NASA's Earth System Enterprise is the first mission dedicated to measuring tropical rainfall through microwave and visible sensors, and includes the first spaceborne rain radar. Tropical rainfall comprises two-thirds of global rainfall. It is also the primary distributor of heat through the atmosphere's circulation. It is this circulation that defines Earth's weather and climate. Understanding rainfall and its variability is crucial to understanding and predicting global climate change. Weather and climate models need an accurate assessment of the latent heating released as tropical rainfall occurs. Currently, cloud model-based algorithms are used to derive latent heating based on rainfall structure. Ultimately, these algorithms can be applied to actual data from TRMM. This study investigates key underlying assumptions used in developing the latent heating algorithms. For example, the standard algorithm is highly dependent on a system's rainfall amount and structure. It also depends on an a priori database of model-derived latent heating profiles based on the aforementioned rainfall characteristics. Unanswered questions remain concerning the sensitivity of latent heating profiles to environmental conditions (both thermodynamic and kinematic), regionality, and seasonality. This study investigates and quantifies such sensitivities and seeks to determine the optimal latent heating profile database based on the results. Ultimately, the study seeks to produce an optimized latent heating algorithm based not only on rainfall structure but also hydrometeor profiles.

Shepherd, J. Marshall; Einaudi, Franco (Technical Monitor)

2000-01-01

213

Cyclic Failure Mechanisms of Thermal and Environmental Barrier Coating Systems Under Thermal Gradient Test Conditions  

NASA Technical Reports Server (NTRS)

Plasma-sprayed ZrO2-8wt%Y2O3 and mullite+BSAS/Si multilayer thermal and environmental barrier coating (TBC-EBC) systems on SiC/SiC ceramic matrix composite (CMC) substrates were thermally cyclic tested under high thermal gradients using a laser high-heat-flux rig in conjunction with furnace exposure in water-vapor environments. Coating sintering and interface damage were assessed by monitoring the real-time thermal conductivity changes during the laser heat-flux tests and by examining the microstructural changes after exposure. Sintering kinetics of the coating systems were also independently characterized using a dilatometer. It was found that the coating failure involved both the time-temperature dependent sintering and the cycle frequency dependent cyclic fatigue processes. The water vapor environments not only facilitated the initial coating conductivity increases due to enhanced sintering and interface reaction, but also promoted later conductivity reductions due to the accelerated coating cracking and delamination. The failure mechanisms of the coating systems are also discussed based on the cyclic test results and are correlated to the sintering and thermal stress behavior under the thermal gradient test conditions.

Zhu, Dongming; Lee, Kang N.; Miller, Robert A.

2002-01-01

214

Ruggedizing infrared integrated Dewar-detector assemblies for harsh environmental conditions  

NASA Astrophysics Data System (ADS)

Cryogenically cooled infrared electro-optical payloads have to operate and survive frequent exposure to harsh vibrational and shock conditions typical of the modern battlefield. This necessitates the development of special approaches to ruggedizing their sensitive components. The ruggedization requirement holds true specifically for Integrated Dewar-Detector Assemblies (IDDA), where the infrared Focal Plane Array (FPA) is usually supported by a thin-walled cold finger enveloped by an evacuated tubular Dewar. Without sufficient ruggedization, harsh environmental vibration may give rise to structural resonance responses resulting in spoiled image quality and even mechanical fractures due to material fatigue. The authors present their approach for the ruggedization of the IDDA by attaching the FPA to a semi-rigid support extending from the dynamically damped Dewar envelope. A mathematical model relies on an experimentally evaluated set of frequency response functions for a reference system and a lumped model of a wideband dynamic absorber. By adding only 2% to the weight of the IDDA, the authors have managed to attenuate the relative deflection and absolute acceleration of the FPA by a factor of 3. The analytical predictions are in full agreement with experiment.

Veprik, Alexander; Ashush, Nataniel; Shlomovich, Baruch; Oppenhaim, Yaakov; Gridish, Yaakov; Kahanov, Ezra; Koifman, Alina; Tuito, Avi

2014-06-01

215

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. PMID:18287030

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

2008-01-01

216

Foundations of Nonlinear Dynamics or Real Dynamics, Ideal Dynamics, Unpredictable Dynamics and the "Schroedinger's Cat Paradox"  

E-print Network

The paper discusses the basic paradoxes of thermodynamics and quantum mechanics. The approaches to solution of these paradoxes are suggested. The first one relies on the influence of the external observer (environment), which disrupts the correlations in the system. The second one is based on the limits of self-knowledge of the system in case of both the external observer and the environment is included in the considered system. The concepts of Real Dynamics, Ideal Dynamics, and Unpredictable dynamics are introduced. The phenomenon of Life is contemplated from the point of view of these Dynamics.

Kupervasser Oleg

2005-08-18

217

Morphology of biogenic iron oxides records microbial physiology and environmental conditions: toward interpreting iron microfossils.  

PubMed

Despite the abundance of Fe and its significance in Earth history, there are no established robust biosignatures for Fe(II)-oxidizing micro-organisms. This limits our ability to piece together the history of Fe biogeochemical cycling and, in particular, to determine whether Fe(II)-oxidizers played a role in depositing ancient iron formations. A promising candidate for Fe(II)-oxidizer biosignatures is the distinctive morphology and texture of extracellular Fe(III)-oxyhydroxide stalks produced by mat-forming microaerophilic Fe(II)-oxidizing micro-organisms. To establish the stalk morphology as a biosignature, morphologic parameters must be quantified and linked to the microaerophilic Fe(II)-oxidizing metabolism and environmental conditions. Toward this end, we studied an extant model organism, the marine stalk-forming Fe(II)-oxidizing bacterium, Mariprofundus ferrooxydans PV-1. We grew cultures in flat glass microslide chambers, with FeS substrate, creating opposing oxygen/Fe(II) concentration gradients. We used solid-state voltammetric microelectrodes to measure chemical gradients in situ while using light microscopy to image microbial growth, motility, and mineral formation. In low-oxygen (2.7-28 ?m) zones of redox gradients, the bacteria converge into a narrow (100 ?m-1 mm) growth band. As cells oxidize Fe(II), they deposit Fe(III)-oxyhydroxide stalks in this band; the stalks orient directionally, elongating toward higher oxygen concentrations. M. ferrooxydans stalks display a narrow range of widths and uniquely biogenic branching patterns, which result from cell division. Together with filament composition, these features (width, branching, and directional orientation) form a physical record unique to microaerophilic Fe(II)-oxidizer physiology; therefore, stalk morphology is a biosignature, as well as an indicator of local oxygen concentration at the time of formation. Observations of filamentous Fe(III)-oxyhydroxide microfossils from a ~170 Ma marine Fe-Si hydrothermal deposit show that these morphological characteristics can be preserved in the microfossil record. This study demonstrates the potential of morphological biosignatures to reveal microbiology and environmental chemistry associated with geologic iron formation depositional processes. PMID:23790206

Krepski, S T; Emerson, D; Hredzak-Showalter, P L; Luther, G W; Chan, C S

2013-09-01

218

Comparison of the behavior of the three superconductors YBCO, Bi2212 and MgB 2 in different environmental conditions  

Microsoft Academic Search

Powders and electrophoretically produced coatings of YBa2Cu3O7?x (YBCO), Bi2Sr2CaCu2O8 (Bi-2212) and MgB2 superconductors were studied for their stability under different environmental conditions, such as UV radiation, various relative humidity conditions, salt spraying, temperature, water environment. It resulted that Bi-2212 is a stable compound, while YBCO is greatly affected by moisture and MgB2 is affected by increasing temperature. All three superconductors

R. Argyropoulou; M. Ochsenkühn-Petropoulou; C. Dounis; P. Karaboulis; A. Altzumailis; K. M. Ochsenkühn

2007-01-01

219

Fine-scale spatial variation in plant species richness and its relationship to environmental conditions in coastal marshlands  

USGS Publications Warehouse

Previous studies have shown that variations in environmental conditions play a major role in explaining variations in plant species richness at community and landscape scales. In this study, we considered the degree to which fine-scale spatial variations in richness could be related to fine-scale variations in abiotic and biotic factors. To examine spatial variation in richness, grids of 1 m(2) plots were laid out at five sites within a coastal riverine wetland landscape. At each site, a 5 x 7 array of plots was established adjacent to the river's edge with plots one meter apart. In addition to the estimation of species richness, environmental measurements included sediment salinity, plot microelevation, percent of plot recently disturbed, and estimated community biomass. Our analysis strategy was to combine the use of structural equation modeling (path modeling) with an assessment of spatial association. Mantel's tests revealed significant spatial autocorrelation in species richness at four of the five sites sampled, indicating that richness in a plot correlated with the richness of nearby plots. We subsequently considered the degree to which spatial autocorrelations in richness could be explained by spatial autocorrelations in environmental conditions. Once data were corrected for environmental correlations, spatial autocorrelation in residual species richness could not be detected at any site. Based on these results, we conclude that in this coastal wetland, there appears to be a fine-scale mapping of diversity to microgradients in environmental conditions.

Mancera, J.E.; Meche, G.C.; Cardona-Olarte, P.P.; Castaneda-Moya, E.; Chiasson, R.L.; Geddes, N.A.; Schile, L.M.; Wang, H.G.; Guntenspergen, G.R.; Grace, J.B.

2005-01-01

220

Surface studies of dry and solid lubricants under different environmental conditions  

NASA Astrophysics Data System (ADS)

Advanced lubrication schemes depend on the presence of specific solids at or the continuous delivery of a gas to the sliding interface to manage friction and wear, and are known to have a strong environmental dependence. An in-vacuo pin-on-disc tribometer was designed to allow controlled environmental testing of the solid lubricants in order to determine the role of atmospheric components on their frictional behavior. Solid lubrication testing of highly oriented pyrolytic graphite, MoS2-Sb2O 3-Au, and MoS2-Sb2O3-C films was carried out under environments of 760 Torr air (50% relative humidity), 150 Torr oxygen, 8 Torr water, 610 Torr nitrogen, and 10-7 Torr vacuum. Dry lubrication testing of the native oxide of silicon (100) surfaces was carried out under environments of 760 Torr air (50% relative humidity), 1 Torr pentanol, and 10-7 Torr vacuum. Pin-on-disc tribometry revealed a strong dependence of friction and wear as a function of sliding environment. MoS2-Sb2O3-Au and MoS2-Sb 2O3-C films were strongly affected by the presence of water molecules. Friction and wear were observed to increase in the presence of partial pressures of water when compared to vacuum, oxygen, and nitrogen environmental testing. Spectroscopic analysis of the MoS2-Sb2O 3-Au and MoS2-Sb2O3-C films showed a general trend of MoS2 expression at the surface of low friction wear tracks. However, high friction could not be directly linked to the expression of a specific species within the wear track. X-ray photoelectron spectroscopy of the tracks created under ambient and water environments yielding high friction showed no clear relationship between the two conditions, even though their frictional behavior was similar. As revealed by atomic force microscopy measurements, the microstructure of the wear tracks of MoS2-Sb2O3-Au films produced under vacuum were predominantly low friction MoS2. The vacuum wear tracks of MoS2-Sb2O3-C films showed a mixed microstructure with both low friction MoS2, and moderate friction C. Ambient wear tracks for MoS2-Sb2O 3-Au films contained a minor, higher friction constituent, identified as Au, in the presence of the major constituent, MoS2. Ambient wear tracks for MoS2-Sb2O3-C films were more complex, expressing a majority of higher friction Sb2O3 and graphite constituents, with a reduced fraction of MoS2. These micro-tribometry measurements correlated well with those made by the pin-on-disc tribometer and X-ray photoelectron spectroscopy characterization. Dry or vapor-phase lubrication methods employing 1-pentanol were effective in reducing the friction of silicon (100) compared to sliding under ambient or vacuum environments. A continuous supply of 1-pentanol served to lubricate silicon surfaces through the formation of a tribochemical film which was composed primarily of (CH2)x species. However, the presence of a tribofilm was not responsible for the lowered friction coefficient, but it did enable the extreme wear protection previously reported for this lubrication technique.

Dudder, Gregory James

221

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

222

Seeking Balance: The Importance of Environmental Conditions in Men and Women Faculty's Well-Being  

ERIC Educational Resources Information Center

Faculty retention is of increasing importance in the current economic climate. We examined the role of an institution's environmental conditions (e.g., climate, collegiality, and administration) in faculty well-being (i.e., job satisfaction, intent to leave, emotional and physical health). Women reported significantly lower well-being and a…

McCoy, Shannon K.; Newell, Ellen E.; Gardner, Susan K.

2013-01-01

223

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. PMID:24062464

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

2013-01-01

224

Quality of life in spite of an unpredictable future: the next of kin of patients with multiple sclerosis.  

PubMed

The aim of the study was to describe the quality of life of the next of kin of patients diagnosed as having multiple sclerosis (MS). Forty-four next of kin were interviewed and thereafter answered the Subjective Quality of Life questionnaire. The next of kin's quality of life emerged as good in terms of both external conditions and interpersonal relationships in both the interviews and the Subjective Quality of Life. In the interviews, most of the next of kin indicated a trusting and secure relationship with the cohabiting partner, but others described a strained situation with an unsatisfactory married/cohabiting life. There was worry about a worsening of the relationship in the future. In addition, the next of kin spoke of a decrease in freedom, self-actualization, and security, also of a more negative general mood and negative emotional experiences. The results of the questionnaire showed that a sense of engagement in life, having energy, self-actualization, self-assuredness, self-acceptance, security, and general mood were significantly correlated with quality of life as a whole. The study confirms that MS is a disease affecting the whole family, and the next of kin were living in uncertainty, facing an unpredictable future. The nurses could start family support groups and help the next of kin to look after their own health, giving advice on health-promoting behavior to make it possible for the person with MS to live at home even if the illness becomes worse. PMID:21207771

Liedström, Elisabeth; Isaksson, Ann-Kristin; Ahlström, Gerd

2010-12-01

225

Alternative splicing and nonsense-mediated decay of circadian clock genes under environmental stress conditions in Arabidopsis  

PubMed Central

Background The circadian clock enables living organisms to anticipate recurring daily and seasonal fluctuations in their growth habitats and synchronize their biology to the environmental cycle. The plant circadian clock consists of multiple transcription-translation feedback loops that are entrained by environmental signals, such as light and temperature. In recent years, alternative splicing emerges as an important molecular mechanism that modulates the clock function in plants. Several clock genes are known to undergo alternative splicing in response to changes in environmental conditions, suggesting that the clock function is intimately associated with environmental responses via the alternative splicing of the clock genes. However, the alternative splicing events of the clock genes have not been studied at the molecular level. Results We systematically examined whether major clock genes undergo alternative splicing under various environmental conditions in Arabidopsis. We also investigated the fates of the RNA splice variants of the clock genes. It was found that the clock genes, including EARLY FLOWERING 3 (ELF3) and ZEITLUPE (ZTL) that have not been studied in terms of alternative splicing, undergo extensive alternative splicing through diverse modes of splicing events, such as intron retention, exon skipping, and selection of alternative 5? splice site. Their alternative splicing patterns were differentially influenced by changes in photoperiod, temperature extremes, and salt stress. Notably, the RNA splice variants of TIMING OF CAB EXPRESSION 1 (TOC1) and ELF3 were degraded through the nonsense-mediated decay (NMD) pathway, whereas those of other clock genes were insensitive to NMD. Conclusion Taken together, our observations demonstrate that the major clock genes examined undergo extensive alternative splicing under various environmental conditions, suggesting that alternative splicing is a molecular scheme that underlies the linkage between the clock and environmental stress adaptation in plants. It is also envisioned that alternative splicing of the clock genes plays more complex roles than previously expected. PMID:24885185

2014-01-01

226

Ultrastructure of potato tubers formed in microgravity under controlled environmental conditions  

NASA Technical Reports Server (NTRS)

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.

Cook, Martha E.; Croxdale, Judith G.; Tibbitts, T. W. (Principal Investigator)

2003-01-01

227

Role of Environmental Conditions on the Fate and Transport of Engineered Nanomaterials in the Subsurface  

NASA Astrophysics Data System (ADS)

Industrial processes and consumer products based on nanotechnology are a fast-rising component of the current economy, predicted to be $1 trillion industry by 2015. As most of the industries are embracing nanotechnology in their production for novel properties and higher efficiency, nanomaterial-based products will capture the significant portion of the consumer market in near future. Hence, nanomaterial-based products will be ubiquitous and the byproducts of the production will be released in the environment, demanding the investigation of fate, transport and toxicity of these novel materials. Therefore, in this study the fate and transport of nanoparticles in aquatic environments have been investigated. Titanium dioxide (TiO2) has been used as model nanoparticles, as it is one of most widely used nanoparticles in consumer products and industry. The project was developed to identify the fundamental mechanisms involved in the transport of nano-TiO2 and the contribution of various environmental parameters including solution chemistry (pH, ionic strength, and ion valence), hydrodynamic effects, and the presence of natural organic matter (NOM) and bacteria. Extensive physicochemical characterization of the nanoparticles was conducted under various solution condition including electrokinetic characterization, hydrodynamic diameter, and stability of nanoparticles. Transport studies have been conducted in both macroscopic (packed-bed column) and microscopic (parallel plate flow cell) systems. The combination of these transport and characterization tools has demonstrated the critical role that pH, ionic strength and valence, NOM, bacteria, primary nanoparticle size and aggregation state play in the transport. Results from both transport systems, as well as bacterial and particle characterization will be presented, as well as the proposed transport and retention mechanisms observed.

Walker, S. L.; Chowdhury, I.

2011-12-01

228

Spatial structuring of an evolving life-history strategy under altered environmental conditions.  

PubMed

Human disturbances to ecosystems have created challenges to populations worldwide, forcing them to respond phenotypically in ways that increase their fitness under current conditions. One approach to examining population responses to disturbance in species with complex life histories is to study species that exhibit spatial patterns in their phenotypic response across populations or demes. In this study, we investigate a threatened population of fall chinook salmon (Oncorhynchus tshawytscha) in the Snake River of Idaho, in which a significant fraction of the juvenile population have been shown to exhibit a yearling out-migration strategy which had not previously been thought to exist. It has been suggested that dam-related environmental changes may have altered the selective pressures experienced by out-migrating fall chinook, driving evolution of a later and more selectively advantageous migration strategy. Using isotopic analysis of otoliths from returning adult spawners, we reconstructed the locations of individual fish at three major juvenile life stages to determine if the representation of the yearling life history was geographically structured within the population. We reconstructed juvenile locations for natal, rearing and overwintering life stages in each of the major spawning areas in the basin. Our results indicate that the yearling life-history strategy is predominantly represented within one of the main spawning regions, the Clearwater River, rather than being distributed throughout the basin. Previous studies have shown the Clearwater River to have cooler temperatures, later hatch dates, and later outmigration of juveniles, indicating a link between environment and expression of the yearling life history. Our data suggest that this new yearling life history may be disproportionally represented in returning adult spawners, indicating selection for this life history within the population. PMID:23423520

Hegg, Jens C; Kennedy, Brian P; Chittaro, Paul M; Zabel, Richard W

2013-08-01

229

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

230

Infrared Spectroscopy of Pollen Identifies Plant Species and Genus as Well as Environmental Conditions  

PubMed Central

Background It is imperative to have reliable and timely methodologies for analysis and monitoring of seed plants in order to determine climate-related plant processes. Moreover, impact of environment on plant fitness is predominantly based on studies of female functions, while the contribution of male gametophytes is mostly ignored due to missing data on pollen quality. We explored the use of infrared spectroscopy of pollen for an inexpensive and rapid characterization of plants. Methodology The study was based on measurement of pollen samples by two Fourier transform infrared techniques: single reflectance attenuated total reflectance and transmission measurement of sample pellets. The experimental set, with a total of 813 samples, included five pollination seasons and 300 different plant species belonging to all principal spermatophyte clades (conifers, monocotyledons, eudicots, and magnoliids). Results The spectroscopic-based methodology enables detection of phylogenetic variations, including the separation of confamiliar and congeneric species. Furthermore, the methodology enables measurement of phenotypic plasticity by the detection of inter-annual variations within the populations. The spectral differences related to environment and taxonomy are interpreted biochemically, specifically variations of pollen lipids, proteins, carbohydrates, and sporopollenins. The study shows large variations of absolute content of nutrients for congenital species pollinating in the same environmental conditions. Moreover, clear correlation between carbohydrate-to-protein ratio and pollination strategy has been detected. Infrared spectral database with respect to biochemical variation among the range of species, climate and biogeography will significantly improve comprehension of plant-environment interactions, including impact of global climate change on plant communities. PMID:24748390

Zimmermann, Boris; Kohler, Achim

2014-01-01

231

The ability of Clostridium bifermentans strains to lactic acid biosynthesis in various environmental conditions.  

PubMed

Clostridium bifermentans strains, isolated from a manure, were examinated for their ability to produce lactic acid from PY medium with glycerol under different pH conditions and when PY medium was supplemented with saccharides such as fructose, sorbitol, glucose, mannose, mannitol, maltose, xylose, raffinose, and arabinose. In the last test performed, the ability of investigated strains to produce lactic acid from mixed carbon source (glycerol plus saccharide) was checked. The strains of Cl. bifermentans, designated as CB 371, CB 374, and CB 376 grew and produced lactic acid on PY medium irrespective of pH and the carbon source used. The optimal lactic acid production on PY medium with glycerol was obtained at pH of 7.0 in case of CB 371 and 376 (19.63 g/L and 16.65 g/L, accordingly) and at pH 8.0 in case of CB 374 (13.88 g/L). The best productivity of lactic acid on PY media by CB 371, CB 374, and CB 376 (above 30 g/L) was observed when mannitol was used as a carbon source. The mixed carbon source did not increase productivity of lactic acid by Cl. bifermentans. The yield of lactic acid was approximately equal to the yield of lactic acid obtained on the medium with only glycerol and lower than in medium with only mannitol. Thus, from the environmental point of view it is more beneficial to use the medium with waste-type material only, such as glycerol. PMID:23503672

Leja, Katarzyna; Myszka, Kamila; Czaczyk, Katarzyna

2013-12-01

232

Incidence of exercise-induced asthma in adolescent athletes under different training and environmental conditions.  

PubMed

The aim of this study was to establish if there were differences in the incidence of exercise-induced bronchospasm between athletes in different sports, which take place under different environmental conditions such as open places, closed courses, and swimming pools with similar exercise intensity (football, basketball, water polo) using the free running test. The study included 90 adolescents (3 groups of 30) aged 14-18 years recruited from academies in northern Greece. All the participants were initially subjected to (a) a clinical examination and cardiorespiratory assessment by a physician and (b) free running test of a 6-minute duration and measurement with a microspirometer of the forced expiratory volume in 1 second (FEV?). Only the participants who had measured a decrease in FEV? ? 10% were reevaluated with the microspirometer during a training session. The examination of all the participants during the free running test showed that 22 athletes, that is, 9, 8, and 5 of football, basketball, and water polo athletes, respectively, demonstrated an FEV? ? 10 drop. Reevaluation of the 22 participants during training showed that 5 out 9 (55%) football athletes, 4 out of 8 basketball athletes (50%), and none of the 5 athletes of the water polo team displayed a drop of FEV? ? 10%. Despite the absence of any significant statistical differences between the 3 groups, the analysis of variances did show a trend of a lower incidence of EIA in the water polo athletes. It was found that a football or basketball game can induce EIA in young athletes but to a lesser degree than the free running test can induce. The water polo can be a safer sport even for participants with a medical history of asthma or allergies. PMID:21912293

Sidiropoulou, Maria P; Kokaridas, Dimitrios G; Giagazoglou, Paraskevi F; Karadonas, Michalis I; Fotiadou, Eleni G

2012-06-01

233

Cold-water coral growth under extreme environmental conditions, the Cape Lookout area, NW Atlantic  

NASA Astrophysics Data System (ADS)

The Cape Lookout cold-water coral area off the coast of North Carolina forms the shallowest and northernmost cold-water coral mound area on the Blake Plateau in the NW Atlantic. Cold-water coral habitats near Cape Lookout are occasionally bathed in the Gulf Stream, which is characterised by oligotrophic warm water and strong surface currents. Here, we present the first insights into the mound distribution and morphology, sedimentary environment and coral cover and near-bed environmental conditions as recorded by bottom landers from this coral area. The mounds occur between 320-550 m water depth and are characterised by high acoustic backscatter indicating the presence of hard structure. Three distinct mound morphologies were observed, (1) a mound with a flattened top at 320 m, (2) multi-summited mounds with a tear drop shape in the middle part of the area and (3) a single mound at 540 m water depth. Echosounder profiles show the presence of a strong reflector underneath all mound structures that forms the base of the mounds. This reflector cropped out at the downstream side of the single mound and consists of carbonate slabs. Video analysis revealed that all mounds are covered by Lophelia pertusa and that living colonies only occur close to the summits of the SSW side of the mounds, which is the side that faces the strongest currents. Off mound areas were characterised by low backscatter and sediment ripples, indicating the presence of relatively strong bottom currents. Two bottom landers were deployed amidst the coral mounds between December 2009 and May 2010. Both landers recorded prominent features near the seabed as well as in the overlying water column. The period between December and April was characterised by several events of increasing temperature and salinity, coinciding with increased flow and near-bed acoustic backscatter. During these events temperature fluctuated by up to 9 °C within a day, which is the largest temperature variability as measured so far in a cold-water coral habitat. Warm events, related to Gulf Stream meanders, had the duration of roughly one week and the current during these events was directed to the NNE. The consequences of such events must be significant given the strong effects of temperature on the metabolism of cold-water corals. Furthermore, elevated acoustic backscatter values and high mass fluxes were also recorded during these events, indicating a second stressor that may affect the corals. The abrasive nature of sand in combination with strong currents might sand blast the corals. We conclude that cold-water corals near Cape Lookout live under extreme conditions that limit mound growth at present.

Mienis, F.; Duineveld, G.; Davies, A. J.; Lavaleye, M. J. N.; Ross, S. W.; Seim, H.; Bane, J.; van Haren, H.; Bergman, M.; de Haas, H.; Brooke, S.; van Weering, T.

2013-12-01

234

Vaccinium myrtillus ameliorates unpredictable chronic mild stress induced depression: possible involvement of nitric oxide pathway.  

PubMed

Chronic unpredictable stressors can produce a situation similar to clinical depression and such animal models can be used for the preclinical evaluation of antidepressants. Nitric oxide, a secondary messenger molecule, has been implicated in neurotransmission, synaptic plasticity, learning, aggression and depression. Vaccinium myrtillus (bilberry) extract is a potent inhibitor of reactive oxygen/nitrogen species and cytokine production. The present study investigated the role of nitric oxide in the antidepressant action of Vaccinium myrtillus in unpredictable chronic mild stress-induced depression in mice. Animals were subjected to different stress paradigms daily for a period of 21 days to induce depressive-like behavior. Pretreatment with L-arginine significantly reversed the protective effect of bilberry (500 mg/kg) on chronic stress-induced behavioral (immobility period, sucrose preference) and biochemical (lipid peroxidation and nitrite levels; endogenous antioxidant activities) in stressed mice. Furthermore, L-NAME (10 mg/kg) pretreatment with a sub-effective dose of bilberry (250 mg/kg) significantly potentiated the protective effect of bilberry extract. The study revealed that modulation of the nitric oxide pathway might be involved in antidepressant-like effects of Vaccinium myrtillus in stressed mice. PMID:22488796

Kumar, Baldeep; Arora, Vipin; Kuhad, Anurag; Chopra, Kanwaljit

2012-04-01

235

Unpredictable chronic mild stress induced behavioral deficits: a comparative study in male and female rats.  

PubMed

Stress is an important precipitant factor for depression. Changes in various body systems that occur in depression are similar to those observed in response to stress. Chronic stress may alter behavioral, neurochemical and physiological responses to drug challenges and novel stressors. Unpredictable chronic mild stress (UCMS) also produces alteration in the serotonergic (5-HT; 5-hydroxytryptamine) neurotransmission. Unpredictable chronic mild stress (UCMS) could be used as an animal model of depression. Neurochemical and behavioral effects of UCMS can be reversed by antidepressant agents, suggesting an important role of serotonin. In rodents, UCMS can elicit depression-like symptoms. The objective of the present study was to evaluate and compare the behavioral deficits induced by chronic mild stress in male and female rats and finding out the vulnerability of the two groups. Male and female rats exposed to UCMS exhibited a significant decrease in cumulative food intake as well as in growth rate. Loco motor activity in home cage and open field was also decreased. Results may contribute to our understanding of the interaction between stress and behavioral functions have to depressive disorders. PMID:25015455

Farhan, Muhammad; Ikram, Huma; Kanwal, Sumera; Haleem, Darakhshan Jabeen

2014-07-01

236

Implementing unpredictability in feeding enrichment for Malayan sun bears (Helarctos malayanus).  

PubMed

Bears in the wild spend large proportions of time in foraging activities. In zoos their time budgets differ markedly from those of their wild counterparts. Feeding enrichment has been documented to increase foraging behavior and to reduce stereotypies. But in general these procedures have no long-term effects and result in habituation. As can be expected by the predictions of the optimal foraging theory, foraging activities are restricted as long as the availability of food is predictable. To quantify the effect of spatial unpredictability, three feeding methods have been designed to stimulate functional foraging behavior in captive Malayan sun bears in the long-term. In order to examine if habituation occurs, the most effective method was tested for 12 consecutive days. Activities of four adult sun bears at the Cologne Zoo were recorded by focal animal recording of foraging behaviors and time sampling of activities for a total of 360?hr. Implementing unpredictability significantly increased the time the bears spent foraging and led to a higher diversity of foraging behaviors. The effects lasted throughout the entire day and no habituation occurred in the course of 12 consecutive days. The study shows how functional species typical behavior in captive Malayan sun bears can be stimulated in the long-term by simulating natural characteristics of food availability. PMID:24402968

Schneider, Marion; Nogge, Gunther; Kolter, Lydia

2014-01-01

237

The relationship of Douglas-fir dwarf mistletoe (Arceuthobium douglasii) to environmental and stand conditions and plant communities in the southern Oregon Cascades.  

E-print Network

??This study examined the relationships between the frequency of occurrence and severity of Douglas-fir dwarf mistletoe (Arceuthobium douglasii Engelmann), environmental and stand conditions, and plant… (more)

Marshall, Katrina

1995-01-01

238

THE ROLE OF INDIVIDUAL VARIABILITY IN POPULATION DYNAMICS UNDER CHANGING ENVIRONMENTAL CONDITIONS  

EPA Science Inventory

Environmental variability can influence species distributions through changes in survival, fecundity, behavior, and metabolic activities. As worldwide coastal populations rise, the associated deforestation and development can increase both quantities and variability in runoff...

239

Session Title Sick about Climate Change: How Changing Environmental Conditions Impact Emerging  

E-print Network

Session Title Sick about Climate Change: How Changing documenting the significant impact of climate change on human and animal disease to climate change environmental impacts on pathogen persistence and the food web

Barnes, Elizabeth A.

240

Fatigue Crack Growth Analysis Under Spectrum Loading in Various Environmental Conditions  

NASA Astrophysics Data System (ADS)

The fatigue process consists, from the engineering point of view, of three stages: crack initiation, fatigue crack growth, and the final failure. It is also known that the fatigue process near notches and cracks is governed by local strains and stresses in the regions of maximum stress and strain concentrations. Therefore, the fatigue crack growth can be considered as a process of successive crack increments, and the fatigue crack initiation and subsequent growth can be modeled as one repetitive process. The assumptions mentioned above were used to derive a fatigue crack growth model based, called later as the UniGrow model, on the analysis of cyclic elastic-plastic stresses-strains near the crack tip. The fatigue crack growth rate was determined by simulating the cyclic stress-strain response in the material volume adjacent to the crack tip and calculating the accumulated fatigue damage in a manner similar to fatigue analysis of stationary notches. The fatigue crack growth driving force was derived on the basis of the stress and strain history at the crack tip and the Smith-Watson-Topper (SWT) fatigue damage parameter, D = ?max??/2. It was subsequently found that the fatigue crack growth was controlled by a two-parameter driving force in the form of a weighted product of the stress intensity range and the maximum stress intensity factor, ? K p K {max/1- p }. The effect of the internal (residual) stress induced by the reversed cyclic plasticity has been accounted for and therefore the two-parameter driving force made it possible to predict the effect of the mean stress including the influence of the applied compressive stress, tensile overloads, and variable amplitude spectrum loading. It allows estimating the fatigue life under variable amplitude loading without using crack closure concepts. Several experimental fatigue crack growth datasets obtained for the Al 7075 aluminum alloy were used for the verification of the proposed unified fatigue crack growth model. The method can be also used to predict fatigue crack growth under constant amplitude and spectrum loading in various environmental conditions such as vacuum, air, and corrosive environment providing that appropriate limited constant amplitude fatigue crack growth data obtained in the same environment are available. The proposed methodology is equally suitable for fatigue analysis of smooth, notched, and cracked components.

Mikheevskiy, S.; Glinka, G.; Lee, E.

2013-03-01

241

Interrelationships of fish and channel environmental conditions with aquatic macrophytes in an Argentine irrigation system  

Microsoft Academic Search

This study examines the relationships between fish, environmental variables and submerged macrophytes within the irrigation\\u000a system of the lower valley of the Río Colorado in southern Argentina. Using Canonical Correspondence Analysis (CCA), the strongest\\u000a environmental gradients detected were conductivity and carp ( Cyprinus carpi) biomass per unit area of channel cross-section.\\u000a These variables were positively associated with each other and

O. A. Fernández; K. J. Murphy; A. López cazorla; M. R. Sabbatini; M. A. Lazzari; J. C. J. Domaniewski; J. H. Irigoyen

1998-01-01

242

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. PMID:23629931

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

243

Household environmental conditions are associated with enteropathy and impaired growth in rural Bangladesh.  

PubMed

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. PMID:23629931

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

2013-07-01

244

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.

2014-02-01

245

Unpredictable chronic stress in juvenile or adult rats has opposite effects, respectively, promoting and impairing resilience.  

PubMed

We evaluated the effects of early maternal deprivation (MD; age 7-14 days) alone or in combination with unpredictable chronic stress (UCS; MDUN; 28-84 days) on anxiety and learning in 90 days old adult rats. We hypothesized that exposure to both stressors (MDUN) would be more detrimental than exposure to one or neither. Unexpectedly, adult rats from the MDUN group did not differ from control animals, whereas adult MD animals exhibited impaired avoidance learning. We next investigated the effect of juvenile-onset (30-90 days) versus adult-onset (60-90 days) stress on avoidance learning in adulthood (90 days). We found that adult-onset chronic stress impaired avoidance learning and memory whereas juvenile-onset stress did not. Thus, the results again indicate that juvenile exposure to UCS induces resilience rather than impairment. PMID:21682654

Ricon, T; Toth, E; Leshem, M; Braun, K; Richter-Levin, G

2012-01-01

246

[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

247

Trafficking of endoplasmic reticulum-retained recombinant proteins is unpredictable in Arabidopsis thaliana  

PubMed Central

A wide variety of recombinant proteins has been produced in the dicot model plant, Arabidopsis thaliana. Many of these proteins are targeted for secretion by means of an N-terminal endoplasmic reticulum (ER) signal peptide. In addition, they can also be designed for ER retention by adding a C-terminal H/KDEL-tag. Despite extensive knowledge of the protein trafficking pathways, the final protein destination, especially of such H/KDEL-tagged recombinant proteins, is unpredictable. In this respect, glycoproteins are ideal study objects. Microscopy experiments reveal their deposition pattern and characterization of their N-glycans aids in elucidating the trafficking. Here, we combine microscopy and N-glycosylation data generated in Arabidopsis leaves and seeds, and highlight the lack of a decent understanding of heterologous protein trafficking. PMID:25309564

De Meyer, Thomas; Depicker, Ann

2014-01-01

248

An Environmental Friendly and Cost Effective Way of Waste Heat Recovery from Split Air Conditioning System  

Microsoft Academic Search

This paper presents the research on the establishment of waste heat recovery device from split air conditioning system. So far, two types of research activities have been conducted to recover waste heat from split type air conditioning systems. For the first type of research the condenser of the air conditioning unit is replaced by copper tube, which is submerged in

M. M. Rahman; Chin Wai Meng; Adrian Ng

249

Movement unpredictability and temporal constraints affect the integration of muscle fatigue information into forward models.  

PubMed

When performing self-paced movements in a fatigued state, internal models can predict the mechanical effects of muscle fatigue. Yet, it is unclear if this is still true when movements are submitted to additional constraints. The purpose of the present study was to investigate the Central Nervous System's (CNS) capacity to integrate fatigue signals into forward models' prediction processes when the movement to perform is unpredictable and temporally constrained. Participants had to perform two different focal movements, depending on the random presentation of color word-color associations (Stroop-like task). They had to trigger fast arm extensions and flexions in a standing posture at the presentation of congruent and incongruent colors, respectively. These movements involve the implementation of predictive mechanisms of control, namely Anticipatory Postural Adjustments (APAs), which have been shown to depend on arm peak acceleration. APA timing and magnitude were measured using surface electromyography. The experimental task was performed before and after a fatiguing protocol involving the prime mover of the flexion movement. According to the assumption that APAs are constructed upstream from the primary motor cortex (M1), up to 1.4s before movement onset on the basis of the processing of the relevant contextual-sensory information, the Stroop-like task aimed to prevent participants from predicting the movement to perform and to reduce movement preparation time. While the fatigue protocol resulted in significant alterations of arm flexion peak accelerations, APAs were not modified post-fatigue as compared to control trials. It is proposed that with unpredictable and temporally constrained movements, the CNS cannot incorporate fatigue signals in internal models' prediction processes to reweight the motor information contained in the efference copy. It is also suggested that APA implementation is based on predictive processes occurring in internal models located upstream from M1. PMID:25086315

Monjo, F; Forestier, N

2014-09-26

250

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

PubMed Central

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 climate events can affect human activities in critical conjunctures that shape particular trajectories of social development. Here we report variable human responses to major environmental events in the Andes with a particular emphasis on the period from anno Domini 500–1500 on the desert north coast of Perú. We show that preindustrial agrarian societies implemented distinct forms of anticipatory response to environmental change and uncertainty. We conclude that innovations in production strategies and agricultural infrastructures in these indigenous societies reflect differential social response to both transient (El Niño–Southern Oscillation events) and protracted (desertification) environmental change. PMID:15024122

Dillehay, Tom D.; Kolata, Alan L.

2004-01-01

251

Numerical Study of the Indoor Environmental Conditions of a Large Athletic Hall Using the CFD Code PHOENICS  

Microsoft Academic Search

This study investigates, experimentally and numerically, the environmental conditions prevailing in a large mechanically ventilated\\u000a athletic hall, with the aid of the computational fluid dynamics code PHOENICS. The indoor space of the building was simulated\\u000a in the PHOENICS environment and the model results were validated against experimental data collected during a 10-day campaign\\u000a in the hall. The measurements included airflow

O. I. Stathopoulou; V. D. Assimakopoulos

2008-01-01

252

The negative effect of environmental geological conditions of some geo-archaeological sites of North Coast and Alexandria  

Microsoft Academic Search

Three geo-archaeological sites at the North Coast and Alexandria, namely, the Alexandria wall (El Shalalat Park site), Abu Soir temple, and Marina excavations, were investigated to determine the negative impact of a salty environmental condition. The monuments suffer from rock decay of different rates. The geo-archaeological sites were built mainly from oolitic limestone blocks (i.e., the Alexandria wall at the

Hani Ibrahim; Gamal Kamh

2005-01-01

253

Autofluorescence of atmospheric bioaerosols - Biological standard particles and the influence of environmental conditions  

NASA Astrophysics Data System (ADS)

Primary biological aerosol particles (PBAP) such as pollen, fungal spores, bacteria, biogenic polymers and debris from larger organisms are known to influence atmospheric chemistry and physics, the biosphere and public health. PBAP can account for up to ~30% of fine and up to ~70% of coarse particulate matter in urban, rural and pristine environment and are released with estimated emission rates of up to ~1000 Tg/a [1]. Continuous measurements of the abundance, variability and diversity of PBAP have been difficult until recently, however. The application of on-line instruments able to detect autofluorescence from biological particles in real-time has been a promising development for the measurement of PBAP concentrations and fluxes in different environments [2,3]. The detected fluorescent biological aerosol particles (FBAP) can be regarded as a subset of PBAP, although the exact relationship between PBAP and FBAP is still being investigated. Autofluorescence of FBAP is usually a superposition of fluorescence from a mixture of individual fluorescent molecules (fluorophores). Numerous biogenic fluorophores such as amino acids (e.g., tryptophan, tyrosine), coenzymes (e.g., NAD(P)H, riboflavin) and biopolymers (e.g., cellulose) emit fluorescent light due to heterocyclic aromatic rings or conjugated double bonds within their molecular structures. The tryptophan emission peak is a common feature of most bioparticles because the amino acid is a constituent of many proteins and peptides. The influence of the coenzymes NAD(P)H and riboflavin on the autofluorescence of bacteria can be regarded as an indicator for bacterial metabolism and has been utilized to discriminate between viable and non-viable organisms [4]. However, very little information is available about other essential biofluorophores in fungal spores and pollen. In order to better understand the autofluorescence behavior of FBAP, we have used fluorescence spectroscopy and fluorescence microscopy to analyze standard bioparticles (pollen, fungal spores, and bacteria) as well as atmospherically relevant chemical substances. We addressed the sensitivity and selectivity of autofluorescence based online techniques. Moreover, we investigated the influence of environmental conditions, such as relative humidity and oxidizing agents in the atmosphere, on the autofluorescence signature of standard bioparticles. Our results will support the molecular understanding and quantitative interpretation of data obtained by real-time FBAP instrumentation [5,6]. [1] Elbert, W., Taylor, P. E., Andreae, M. O., & Pöschl, U. (2007). Atmos. Chem. Phys., 7, 4569-4588. [2] Huffman, J. A., Treutlein, B., & Pöschl, U. (2010). Atmos. Chem. Phys., 10, 3215-3233. [3] Pöschl, U., et al. (2010). Science, 329, 1513-1516. [4] Lakowicz, J., Principles of fluorescence spectroscopy, Plenum publishers, New York, 1999. [5] Pöhlker, C., Huffman, J. A., & Pöschl, U., (2012). Atmos. Meas. Tech., 5, 37-71. [6] Pöhlker, C., Huffman, J. A., Förster J.-D., & Pöschl, U., (2012) in preparation.

Pöhlker, Christopher; Huffman, J. Alex; Förster, Jan-David; Pöschl, Ulrich

2013-04-01

254

Bacterial community composition associated with freshwater algae: species specificity vs. dependency on environmental conditions and source community.  

PubMed

We studied bacterial associations with the green alga Desmodesmus armatus and the diatom Stephanodiscus minutulus under changing environmental conditions and bacterial source communities, to evaluate whether bacteria-algae associations are species-specific or more generalized and determined by external factors. Axenic and xenic algae were incubated in situ with and without allelopathically active macrophytes, and in the laboratory with sterile and nonsterile lake water and an allelochemical, tannic acid (TA). Bacterial community composition (BCC) of algae-associated bacteria was analyzed by denaturing gradient gel electrophoresis (DGGE), nonmetric multidimensional scaling, cluster analyses, and sequencing of DGGE bands. BCC of xenic algal cultures of both species were not significantly affected by changes in their environment or bacterial source community, except in the case of TA additions. Species-specific interactions therefore appear to overrule the effects of environmental conditions and source communities. The BCC of xenic and axenic D. armatus cultures subjected to in situ bacterial colonization, however, had lower similarities (ca. 55%), indicating that bacterial precolonization is a strong factor for bacteria-algae associations irrespective of environmental conditions and source community. Our findings emphasize the ecological importance of species-specific bacteria-algae associations with important repercussions for other processes, such as the remineralization of nutrients, and organic matter dynamics. PMID:23030046

Eigemann, Falk; Hilt, Sabine; Salka, Ivette; Grossart, Hans-Peter

2013-03-01

255

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

256

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

E-print Network

tailings produced at the mill. However, pyrite is strongly oxidative and generates acid mine drainage, 2002). To limit acid mine drainage generation, mining companies must apply control strategies that aim and environmentally effective technique to decrease acid generation potential of mine tailings (Bois et al, 2004

Aubertin, Michel

257

Variation in gene expression of Andropogon gerardii in response to altered environmental conditions  

E-print Network

at multiple scales ­ from gene expression to morphology. Plants perceive and respond to their environment stress than in response to water stress. We also identified candidate genes that demonstrated to respond more rapidly to environmental change and stress. Moreover, because extensive genomic information

Kaufman, Glennis A.

258

ENVIRONMENTAL CONDITIONS IN NORTHERN GULF OF MEXICO COASTAL WATERS FOLLOWING HURRICANE KATRINA  

EPA Science Inventory

On the morning of August 29, 2005 Hurricane Katrina struck the coast of Louisiana, between New Orleans and Biloxi, Mississippi, as a strong category three hurricane on the Saffir-Simpson scale. The massive winds and flooding had the potential for a tremendous environmental impac...

259

Fuzzy Comfort and its Use in the Design of an Intelligent Coordinator of Fuzzy Controller-Agents for Environmental Conditions Control in Buildings  

Microsoft Academic Search

The theme of this paper is the design of an intelligent coordinator (IC) of fuzzy controller-agents (FCAs) to control indoor environmental conditions in buildings by using a 3-D fuzzy comfort set. The basic factors that participate in the control of indoor environmental conditions are the controllers and users' comfort requirements. Harmonization of these factors results in energy saving, and occupants'

Anastasios I. Dounis; Christos Caraiscos

260

Modeling the effects of environmental conditions on HT2 and T2 toxin accumulation in field oat grains.  

PubMed

Fusarium head blight (FHB) of wheat and barley has been extensively researched worldwide; in contrast, there is limited information on the effects of environmental conditions on Fusarium toxin accumulation in oat grains. More than 300 samples of oat grain from various regions of the United Kingdom from 2006 to 2008 were analyzed for mycotoxin contamination due to infection by Fusarium spp. HT2 and T2 toxins were the two most commonly detected, and their concentrations in individual samples were highly correlated. Hourly weather data were obtained from meteorological recording stations near most of the sampling sites. Statistical modeling was applied to both the original toxin (HT2 plus T2) data and the toxin data adjusted for oat cultivars and number of cereal crops in the previous four seasons. Accumulation of HT2 and T2 toxin was positively correlated with warm and wet conditions during early May and dry conditions thereafter. Using a collection of 51 environmental variables summarized over three lengths (10, 15, and 20 days) of time periods encompassing early May, late May, and early July, all-subsets regression showed that many models, consisting of three to six predictor variables, could be identified with similar explanatory strength for the effect of environmental conditions on toxin accumulation. Most important predictor variables were related to wet conditions during the early-May period, which was before anthesis. These results suggest that the predominant period for Fusarium langsethiae infection of oat is likely to be before rather than during anthesis, as for other head blight pathogens. These empirical models may be further improved by using quantified pathogen biomass within the grains and weather predictor variables summarized in relation to plant growth stages (instead of calendar times). PMID:23883158

Xu, Xiangming; Madden, Laurence V; Edwards, Simon G

2014-01-01

261

Wind environmental conditions in passages between two long narrow perpendicular buildings  

Microsoft Academic Search

This paper presents wind tunnel measurements of pedestrian wind conditions in passages between various configurations of two long narrow perpendicular buildings in open country exposure. The investigated parameters are passage width, building height and wind direction. The measurements were made along the passage centerline. The aim of the paper is to provide more insight in the pedestrian wind conditions in

BJE Blocken; T. Stathopoulos; J Carmeliet

2008-01-01

262

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

263

ENVIRONMENTAL CONDITIONS AND BREEDING EXPERIENCE AFFECT COSTS OF REPRODUCTION IN BLUE PETRELS  

Microsoft Academic Search

Abstract. Using data from a 17-year study of individually marked Blue Petrels, we examined how survival and breeding probability varied with experience and breeding status, and looked for costs of first reproduction, taking into account environmental and individual variability. Using multistate capture?recapture models,with four states (inexperienced non- breeders, first-time breeders, experienced breeders, and experienced nonbreeders), we found that first-time breeders,had,a

Christophe Barbraud; Henri Weimerskirch

2005-01-01

264

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

265

New approaches to study the relationship between stomatal conductance and environmental factors under Mediterranean climatic conditions  

NASA Astrophysics Data System (ADS)

The most frequently models used (Ball-Berry and Jarvis-type models) to estimate stomatal conductance (Gs) values have limitations when applied to plants growing in Mediterranean climate. To overcome these limitations, several statistical methodologies (Multiple Linear Regression, Neural Net Analysis (NNA)) were used to build models to predict Gs. However, all these models were unable to integrate the physiological response of plants to the overall limiting environmental parameters in our Mediterranean site especially during the summer drought. With this in mind, it is relevant to find alternative approaches which link Gs response to environmental limitations of plants. In this paper, we demonstrate that: (1) the different linear and nonlinear statistical approaches used significantly affect the weights of the environmental variables which are utilized in semi-empirical Gs models; (2) a tight relationship exists between summer values of Gs and the rate of accumulated precipitations ( ?) in the first 5 months of the year, thus allowing to predict Gs in a quantitative way; and (3) the latter is also related to different water-use strategies adopted by plants in response to drought stress in the summer period. Because ? is easily calculated, it is an interesting parameter for the Gs modelling addressed to understand many important aspects of the plant-environment interactions, such as water relations and pollutant uptake.

Vitale, Marcello; Anselmi, Silvia; Salvatori, Elisabetta; Manes, Fausto

266

Assessing the aggregation behaviour of iron oxide nanoparticles under relevant environmental conditions using a multi-method approach.  

PubMed

Iron nanoparticles are becoming increasingly popular for the treatment of contaminated soil and groundwater; however, their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Assessing their stability under environmental conditions is crucial for determining their environmental fate. A multi-method approach (including different size-measurement techniques and the DLVO theory) was used to thoroughly characterise the behaviour of iron oxide nanoparticles (Fe2O3NPs) under environmentally relevant conditions. Although recent studies have demonstrated the importance of using a multi-method approach when characterising nanoparticles, the majority of current studies continue to use a single-method approach. Under some soil conditions (i.e. pH 7, 10 mM NaCl and 2 mM CaCl2) and increasing particle concentration, Fe2O3NPs underwent extensive aggregation to form large aggregates (>1 ?m). Coating the nanoparticles with dissolved organic matter (DOM) was investigated as an alternative "green" solution to overcoming the aggregation issue instead of using the more commonly proposed polyelectrolytes. At high concentrations, DOM effectively covered the surface of the Fe2O3NPs, thereby conferring negative surface charge on the particles across a wide range of pH values. This provided electrostatic stabilisation and considerably reduced the particle aggregation effect. DOM-coated Fe2O3NPs also proved to be more stable under high ionic strength conditions. The presence of CaCl2, however, even at low concentrations, induced the aggregation of DOM-coated Fe2O3NPs, mainly via charge neutralisation and bridging. This has significant implications in regards to the reactivity and fate of these materials in the environment. PMID:23764608

Chekli, Laura; Phuntsho, Sherub; Roy, Maitreyee; Lombi, Enzo; Donner, Erica; Shon, Ho Kyong

2013-09-01

267

Changes in body composition during breeding: Reproductive strategies of three species of seabirds under poor environmental conditions.  

PubMed

Seabirds differ dramatically in life history traits and breeding strategies. For example, gulls have short incubation shifts (several hours) and high metabolic rates, auks have medium-length incubation shifts (12-24h) and high metabolic rates, and petrels have long incubation shifts (days) and low metabolic rates. How these different strategies affect the dynamics of body components is poorly known. We compared body, organ and lipid mass changes among three different seabirds (gull: black-legged kittiwake Rissa tridactyla; auk: thick-billed murre Uria lomvia; petrel: northern fulmar Fulmarus glacialis) at Prince Leopold Island, Nunavut, Canada during 2002 (a year with low reproductive success and poor chick growth across all three species). This study is among the first to compare mass and lipid dynamics among different species foraging in the same food web and at similar trophic levels during the same breeding season (same environmental conditions). In fulmars and murres, most of decreases in body mass reflected decreases in lipid mass while in kittiwakes the increase in body mass reflected an increase in lean mass, especially the muscle. The species with the longest fasting endurance (incubation shift length) had the highest percent body lipids during incubation (fulmars: 13.3%, murres: 7.3%, kittiwakes: 6.9%), the highest variability in body lipids, tended to regulate body mass primarily through lipid stores and tended to regulate exercise and digestive organs separately. In contrast, in the species with the highest metabolic rate, all organ systems were adjusted similarly and in relation to body mass, and in a similar manner between incubation (stress due to heavy ice conditions) and chick-rearing (lower stress due to ice-free conditions). In high metabolic rate species, we suggest that organ size varies in response to environmental stress. We conclude that the organ dynamics of seabirds are set by a combination of key life history traits (like incubation shift and metabolic rate) and environmental conditions. PMID:20888927

Jacobs, Shoshanah R; Edwards, Darryl B; Ringrose, Julian; Elliott, Kyle H; Weber, Jean-Michel; Gaston, Anthony J

2011-01-01

268

Fatty acid profiles of blood lipids in a population group in Tibet: correlations with diet and environmental conditions.  

PubMed

The aim of this study was to compare blood fatty acid profiles of two population groups: Italian and Tibetan, differing with regard to ethnic, life style and environmental aspects. Additionally the collection of two staple foods provided the opportunity to analyze typical Tibetan dishes. A new, simple, rapid, and substantially non invasive method for fatty acid (FA) analysis of blood lipids was applied to healthy Italian (n=14) and Tibetan (n=13) subjects. Blood drops obtained from the ear lobe of Tibetans or the fingertip of Italians were adsorbed by a special strip of paper and processed for fatty acid analysis. The fatty acid profiles of the two groups are different, and environmental factors, such as dietary fats and altitudes of Milan, Italy (a low altitude site), and Lhasa, Tibet (a high altitude site) appear to contribute to these differences. More specifically, in Ti-betans higher levels of monounsaturated fatty acids, including the 22 and 24 carbon molecules, were found. This appears to be derived mainly from locally consumed fats (mustard seed oil), and are associated with lower levels of total polyunsaturated fatty acids and higher levels of selected omega 3 fatty acids, when compared to the Italians. These relatively higher levels of monounsaturated fatty acids may also indicate means of adaptation to local prooxidant conditions. The observed differences in blood fatty acid profiles in Tibetans vs. Italians appear to result both from dietary factors and adaptation to local environmental conditions such as the high altitude of the Tibetan location. PMID:18364331

Risé, Patrizia; Marangoni, Franca; Martiello, Antonella; Colombo, Claudio; Manzoni, Cristina; Marconi, Claudio; Cattabeni, Flaminio; Galli, Claudio

2008-01-01

269

Comparison of 905 nm and 1550 nm semiconductor laser rangefinders' performance deterioration due to adverse environmental conditions  

NASA Astrophysics Data System (ADS)

Laser rangefinder performance (i.e., maximum range) is strongly affected by environment due to visibility-dependent laser attenuation in the atmosphere and target reflectivity variations induced by surface condition changes (dry vs. wet). Both factors have their unique spectral features which means that rangefinders operating at different wavelengths are affected by specific environmental changes in a different way. Current state of the art TOF (time of flight) semiconductor laser rangefinders are based mainly on two wavelengths: 905 nm and 1550 nm, which results from atmospheric transmission windows and availability of high power pulsed sources. The paper discusses the scope of maximum range degradation of hypothetical 0.9 ?m and 1.5 ?m rangefinders due to selected water-related environmental effects. Atmospheric extinction spectra were adapted from Standard Atmosphere Model and reflectance fingerprints of various materials have been measured. It is not the aim of the paper to determine in general which wavelength is superior for laser range finding, since a number of criteria could be considered, but to verify their susceptibility to adverse environmental conditions.

Wojtanowski, J.; Zygmunt, M.; Kaszczuk, M.; Mierczyk, Z.; Muzal, M.

2014-09-01

270

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

271

Environmentally \\  

Microsoft Academic Search

Summary A sustainable industrial growth will influence the cement and concrete industry in many respects as the construction industry has environmental impact due to high consumption of energy and other resources. One important issue is the use of environmental-friendly concrete (\\

Carola Edvardsen

272

Assessing learned associations between conditioned cocaine reward and environmental stimuli in the Wistar Kyoto rat.  

PubMed

Clinical studies demonstrate that anxiety disorders increase the risk of substance use disorder. However, few studies have directly assessed anxiety as a vulnerability factor in processing of rewarding stimuli. The Wistar–Kyoto (WKY) rat has been proposed as a model of anxiety vulnerability because it exhibits extreme behavioral inhibition in novel and social environments; yet, it displays paradoxical rapid active avoidance learning that is resistant to extinction. The present study was designed to characterize the acquisition and persistence of cocaine conditioned place preference (CPP) in WKY rats. In the first of a series of three experiments, adult male WKY and Sprague Dawley (SD) rats were given six pairings of cocaine (3, 5, 10, 15 mg/kg) or saline on alternating days. SD rats developed cocaine-induced CPP to each of the four doses of cocaine tested. In contrast, WKY rats demonstrated CPP when conditioned with 3, 5, and 10 mg/kg, but displayed no preference to the 15 mg/kg dose. Next, separate groups of rats were subject to an extended CPP paradigm, which included acquisition, extinction and reinstatement phases. Rats were conditioned with cocaine and saline on alternating days using either a 6/6 (as above) or 4/4 conditioning regimen. Both SD and WKY rats acquired a lasting CPP with the 6/6 conditioning regimen. Results from the 4/4 conditioning regimen show that SD, but not WKY, rats acquired CPP. Preference scores for SD rats during the cocaine primed reinstatement test were significantly different from pretest scores indicating reinstatement of CPP in this group. Paradoxically, WKY rats demonstrated a latent sensitization to the conditioned rewarding effects of cocaine during the drug-primed reinstatement test. Taken together, WKY rats appear to be more sensitive to high doses of cocaine and need more experience with the drug to acquire a preference than SD rats. PMID:22922075

Dennis, Torry S; Beck, Kevin D; Bobzean, Samara A Morris; Dougall, Angela Liegey; Perrotti, Linda I

2012-11-01

273

Evaluation of chemical conversion material (protective coating) exposed to space environmental conditions  

NASA Technical Reports Server (NTRS)

This report focuses on the development of an operational Rutherford backscattering spectrometry (RBS) system and shows the application of such a system on a space environmental test. Thin films of aluminum and tantalum were deposited on diamond substrates. These films were anodized and preexposure characterization spectra obtained using RBS and total hemispherical reflectance. The samples were exposed to energetic protons then postexposure characterization spectra was obtained using the same techniques. Conclusions based on the comparison of preexposure and postexposure spectra are presented. RBS comparison spectra show no change in the metal/metal oxide interface, while the comparison reflectance data indicate change. Explanations for this reflectance change are presented in this report.

Edwards, D. L.

1993-01-01

274

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

275

Results on the survival of cryptobiotic cyanobacteria samples after exposure to Mars-like environmental conditions  

NASA Astrophysics Data System (ADS)

Tests on cyanobacteria communities embedded in cryptobiotic crusts collected in hot and cold deserts on Earth were performed under Mars-like conditions. The simulations were realized as a survey, to find the best samples for future research. During the tests organisms have to resist Mars-like conditions such as atmospheric composition, pressure, variable humidity (saturated and dry conditions) and partly strong UV irradiation. Organisms were tested within their original habitat inside the crust. Nearly half of the cryptobiotic samples from various sites showed survival of a substantial part of their coexisting organisms. The survival in general depended more on the nature of the original habitat and type of the sample than on the different conditions they were exposed to. The best survival was observed in samples from United Arab Emirates (Jebel Ali, 25 km SW of Dubai town) and from Western Australia (near the South edge of Lake Barley), by taxa: Tolypothrix byssoidea, Gloeocapsopsis pleurocapsoides, Nostoc microscopicum, Leptolyngbya or Symploca sp. At both places in salty desert areas members of the Chenopodiaceae family dominated among the higher plants and in the cryptobiotic crust cyanobacterial taxa Tolypothrix was dominant. These organisms were all living in salty locations with dry conditions most of the year. Among them Tolypothrix, Gloeocapsopsis and Symploca sp. were tested in Mars simulation chambers for the first time. The results suggest that extremophiles should be tested with taken into account the context of their original microenvironment, and also the importance to analyse communities of microbes beside single organisms.

de Vera, J.-P.; Dulai, S.; Kereszturi, A.; Koncz, L.; Lorek, A.; Mohlmann, D.; Marschall, M.; Pocs, T.

2014-01-01

276

Variation of cyanobacteria with different environmental conditions in Nansi Lake, China.  

PubMed

Nansi Lake is located on the east line of the South-to-North Water Diversion Project in China. A comprehensive study was carried out to investigate the spatial and temporal distribution of cyanobacteria in the lake from June 2008 to May 2011 based on monthly sample monitoring from five stations. The effect of environmental factors on cyanobacterial abundance was also evaluated. The cyanobacterial community contained 15 genera and 23 species. The cyanobacterial abundance of each monitoring station ranged from 0 to 1.53 x 10(7) cells/L with an average of 1.45 x 10(6) cells/L, which accounted for 11.66% of the total phytoplankton abundance. The dominant species of cyanobacteria were Pseudanabaena (32.94%) and Merismopedia (19.85%), not the bloom-forming algae such as Microcystis and Anabaena. In addition, the cyanobacterial community structure and water quality variables changed substantially over the survey period. Redundancy analysis (RDA) suggested that temperature and phosphorus were important environmental factors that affected cyanobacteria. Temperature was the most important factor affecting cyanobacterial abundance. The effect of phosphorus on cyanobacterial abundance was more notable in warm periods than in periods with low temperature. PMID:23513680

Tian, Chang; Peil, Haiyan; Hu, Wenrong; Xie, Jun

2012-01-01

277

Transcriptional response of the model planctomycete Rhodopirellula baltica SH1T to changing environmental conditions  

PubMed Central

Background The marine model organism Rhodopirellula baltica SH1T was the first Planctomycete to have its genome completely sequenced. The genome analysis predicted a complex lifestyle and a variety of genetic opportunities to adapt to the marine environment. Its adaptation to environmental stressors was studied by transcriptional profiling using a whole genome microarray. Results Stress responses to salinity and temperature shifts were monitored in time series experiments. Chemostat cultures grown in mineral medium at 28°C were compared to cultures that were shifted to either elevated (37°C) or reduced (6°C) temperatures as well as high salinity (59.5‰) and observed over 300 min. Heat shock showed the induction of several known chaperone genes. Cold shock altered the expression of genes in lipid metabolism and stress proteins. High salinity resulted in the modulation of genes coding for compatible solutes, ion transporters and morphology. In summary, over 3000 of the 7325 genes were affected by temperature and/or salinity changes. Conclusion Transcriptional profiling confirmed that R. baltica is highly responsive to its environment. The distinct responses identified here have provided new insights into the complex adaptation machinery of this environmentally relevant marine bacterium. Our transcriptome study and previous proteome data suggest a set of genes of unknown functions that are most probably involved in the global stress response. This work lays the foundation for further bioinformatic and genetic studies which will lead to a comprehensive understanding of the biology of a marine Planctomycete. PMID:19725962

Wecker, Patricia; Klockow, Christine; Ellrott, Andreas; Quast, Christian; Langhammer, Philipp; Harder, Jens; Glockner, Frank Oliver

2009-01-01

278

The effects of early environmental conditions on the reproductive and somatic development of juvenile guinea pigs (Cavia aperea f. porcellus)  

PubMed Central

Little is known about the effects of the early environment on the development of non-seasonally reproducing species like the domestic guinea pig (Cavia aperea f. porcellus). Although guinea pigs reproduce throughout the year, there is evidence for environmental sensitivity of their reproductive physiology. To investigate the sensitivity of juvenile body weight and puberty to differences in the prenatal and early postnatal environment, subjects were exposed to either of two experimental conditions mimicking seasonal variation: a long photoperiod with 25 °C ambient temperature (“LD/25 °C”), or a short photoperiod with 15 °C (“SD/15 °C”). Mean body weight of F1-males from LD/25 °C-conditions was higher than that of SD/15 °C-males during the whole pubertal period, although the difference was significant only during the early growth phase. Testosterone concentrations also differed significantly between the two treatment groups, pointing to an earlier pubertal onset in LD/25 °C- than SD/15 °C-males. In F1-females, treatment effects on body weight or age at first estrus were absent. This indicates that the somatic and reproductive development is more sensitive to early photoperiod and temperature conditions in male than female guinea pigs, and that other environmental factors may also play a crucial role for reproductive maturation in this species. PMID:17977535

Bauer, Barbara; Womastek, Irene; Dittami, John; Huber, Susanne

2011-01-01

279

Robust vehicle detection under various environmental conditions using an infrared thermal camera and its application to road traffic flow monitoring.  

PubMed

We have already proposed a method for detecting vehicle positions and their movements (henceforth referred to as "our previous method") using thermal images taken with an infrared thermal camera. Our experiments have shown that our previous method detects vehicles robustly under four different environmental conditions which involve poor visibility conditions in snow and thick fog. Our previous method uses the windshield and its surroundings as the target of the Viola-Jones detector. Some experiments in winter show that the vehicle detection accuracy decreases because the temperatures of many windshields approximate those of the exterior of the windshields. In this paper, we propose a new vehicle detection method (henceforth referred to as "our new method"). Our new method detects vehicles based on tires' thermal energy reflection. We have done experiments using three series of thermal images for which the vehicle detection accuracies of our previous method are low. Our new method detects 1,417 vehicles (92.8%) out of 1,527 vehicles, and the number of false detection is 52 in total. Therefore, by combining our two methods, high vehicle detection accuracies are maintained under various environmental conditions. Finally, we apply the traffic information obtained by our two methods to traffic flow automatic monitoring, and show the effectiveness of our proposal. PMID:23774988

Iwasaki, Yoichiro; Misumi, Masato; Nakamiya, Toshiyuki

2013-01-01

280

Physiological responses of a rodent to heliox reveal constancy of evaporative water loss under perturbing environmental conditions.  

PubMed

Total evaporative water loss of endotherms is assumed to be determined essentially by biophysics, at least at temperatures below thermoneutrality, with evaporative water loss determined by the water vapor deficit between the animal and the ambient air. We present here evidence, based on the first measurements of evaporative water loss for a small mammal in heliox, that mammals may have a previously unappreciated ability to maintain acute constancy of total evaporative water loss under perturbing environmental conditions. Thermoregulatory responses of ash-grey mice (Pseudomys albocinereus) to heliox were as expected, with changes in metabolic rate, conductance, and respiratory ventilation consistent with maintaining constancy of body temperature under conditions of enhanced heat loss. However, evaporative water loss did not increase in heliox. This is despite our confirmation of the physical effect that heliox augments evaporation from nonliving surfaces, which should increase cutaneous water loss, and increases minute volume of live ash-grey mice in heliox to accommodate their elevated metabolic rate, which should increase respiratory water loss. Therefore, mice had not only a thermoregulatory but also a hygroregulatory response to heliox. We interpret these results as evidence that ash-grey mice can acutely control their evaporative water loss under perturbing environmental conditions and suggest that hygroregulation at and below thermoneutrality is an important aspect of the physiology of at least some small mammals. PMID:25163919

Cooper, Christine Elizabeth; Withers, Philip Carew

2014-10-15

281

Droplet-turbulence interactions in sprays exposed to supercritical environmental conditions  

NASA Technical Reports Server (NTRS)

The goal of this research was to experimentally characterize the behavior of droplets in vaporizing sprays under conditions typical of those encountered in high pressure combustion systems such as liquid fueled rocket engines. Of particular interest are measurements of droplet drag and lift, droplet dispersion, droplet heating, and droplet vaporization under both subcritical and supercritical conditions. A summary of the major accomplishments achieved during the period from June 1990 through June 1993, a brief description and status report on five research areas, which were directly or indirectly supported by this grant, and a list of publications and personnel associated with this research is included.

Santavicca, Domenic A.

1993-01-01

282

Intrinsic measurement bias on computed tomography scout view is unpredictable: Computed tomography pelvimetry using a phantom.  

PubMed

Our aim was to determine the degree of bias in CT scanogram measurements. We obtained standard lateral and anteroposterior (AP) pelvimetry scanograms of a phantom pelvis after placing ball bearings or aluminium rods to mark bony landmarks. Computed tomography pelvimetry was carried out at the manufacturer-recommended table height on two commercial CT scanners and at 10-mm increments up to 50 mm above and below this height. The AP inlet, AP outlet, interspinous distance and transverse diameters were each measured three times for each scanogram. The true measurements were obtained directly from the disassembled phantom. Bias was defined as the difference between the CT measurement and the true measurement. Observer error was negligible. The transverse diameter was overestimated at high table positions and underestimated at low table positions on both scanners (+6 to -10 mm). After correcting for geometric distortion, up to 6 mm bias was still present. The point at which no bias occurred was different for each scanner and did not correspond to the manufacturers' recommended table height. The outlet was overestimated on both scanners by up to 5 mm. The true inlet measurement was overestimated by 1.2 mm. The interspinous distance was minimally underestimated on both scanners. The measurements on CT scanogram were underestimated or overestimated in an inconsistent and unpredictable fashion, varying from one type of measurement to another and from CT scanner to CT scanner. This has implications for the accuracy and clinical utility of measurements obtained from a CT scanogram. PMID:16635030

Anderson, N G; Fenwick, J L; Wells, J E

2006-04-01

283

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

284

Note: A technique to capture and compose streak images of explosive events with unpredictable timing  

NASA Astrophysics Data System (ADS)

The authors describe a method to capture optical data and construct digitized streak images for analysis of high-speed phenomena with unpredictable timing by using a high-speed video camera and software routines. Advances in high-speed video camera technology have led to development of cameras with frame rates (1×106 frames per second) and spatial resolution (1280×800 pixels) suitable to capture fast phenomena, such as detonation in high explosives (?10 km s-1), on small enough scales to be convenient for laboratory experiments. Further, relatively long-duration recordings (?1 s) are maintained in a rolling buffer in volatile memory allowing the entire frame sequence to be recorded pretrigger, thus obviating the need for precisely located diagnostic triggers. The method described was used to capture the progression of luminous reaction during the deflagration-to-detonation transition of the HMX-based (octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine) plastic bonded explosive (PBX) formulation during cookoff.

Parker, Gary R.; Asay, Blaine W.; Dickson, Peter M.

2010-01-01

285

Note: A technique to capture and compose streak images of explosive events with unpredictable timing.  

PubMed

The authors describe a method to capture optical data and construct digitized streak images for analysis of high-speed phenomena with unpredictable timing by using a high-speed video camera and software routines. Advances in high-speed video camera technology have led to development of cameras with frame rates (1 x 10(6) frames per second) and spatial resolution (1280 x 800 pixels) suitable to capture fast phenomena, such as detonation in high explosives (< or = 10 km s(-1)), on small enough scales to be convenient for laboratory experiments. Further, relatively long-duration recordings (> or = 1 s) are maintained in a rolling buffer in volatile memory allowing the entire frame sequence to be recorded pretrigger, thus obviating the need for precisely located diagnostic triggers. The method described was used to capture the progression of luminous reaction during the deflagration-to-detonation transition of the HMX-based (octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine) plastic bonded explosive (PBX) formulation during cookoff. PMID:20113140

Parker, Gary R; Asay, Blaine W; Dickson, Peter M

2010-01-01

286

Persistent behavioral and neurochemical sensitization to an acute injection of methamphetamine following unpredictable stress.  

PubMed

Prior research in humans and animals suggest that exposure to chronic stress alters the response to drugs of abuse, increasing vulnerability to drug addiction. Chronic unpredictable stress (CUS) has been shown to augment the increase of dopamine in the striatum when challenged with high doses of methamphetamine immediately following stress exposure, however it is not known whether this neurochemical stress-sensitization continues after the cessation of the stressors or if behavioral sensitization is also present. Therefore, the current study examined the immediate and delayed effects of CUS on methamphetamine-induced behaviors and striatal dopamine levels. Male rats were exposed to 10 days of CUS and then tested in either an open field box to assess locomotion or underwent in vivo microdialysis to measure striatal dopamine levels immediately following CUS or after a 1-2 week delay. All rats exposed to CUS showed a potentiated locomotor response immediately following an acute injection of 7.5mg/kg methamphetamine compared to non-stressed control rats. Both groups of CUS rats also showed augmented dopamine release and rectal temperatures following methamphetamine with prolonged increases in the CUS rats tested after a delay. These results suggest that CUS increases the sensitivity of a rat to a single injection of methamphetamine and that the increased sensitivity persists for up to 2 weeks following the last stressor. PMID:25036423

Matuszewich, Leslie; Carter, Samantha; Anderson, Eden M; Friedman, Ross D; McFadden, Lisa M

2014-10-01

287

Environmental bias? Effects of housing conditions, laboratory environment and experimenter on behavioral tests.  

PubMed

Behavioral testing does not always yield similar results when replicated in different laboratories, and it usually remains unclear whether the variability in results is caused by different laboratory environments or different experimenters conducting the tests. In our study, we applied a systematic variation of housing conditions, laboratories and experimenters in order to test the influence of these variables on the outcome of behavioral tests. We wanted to know whether known effects of different housing conditions on behavior can be demonstrated regardless of the respective laboratory and experimenters. In this study, we compared the behavior of mice kept under enriched housing conditions with mice kept in unstructured cages regarding their exploratory, locomotor and anxiety-related behavior in the barrier test, in the open-field test and in the elevated plus-maze test. Experiments were conducted by six different persons in two different laboratories. In spite of an extensive protocol standardizing laboratory environment, animal maintenance and testing procedures, significant differences in absolute values between different laboratories as well as between different experimenters were noticed in the barrier test and in the elevated plus-maze test but not in the open-field test. However, with regard to the differences between enriched and unstructured housing conditions, overall consistent results were achieved by different experimenters in both laboratories. We conclude that the reliability of behavioral phenotyping is not challenged seriously by experimenter and laboratory environment as long as appropriate standardizations are met and suitable controls are involved. PMID:16436190

Lewejohann, L; Reinhard, C; Schrewe, A; Brandewiede, J; Haemisch, A; Görtz, N; Schachner, M; Sachser, N

2006-02-01

288

Challenges for Physical Characterization of Silver Nanoparticles Under Pristine and Environmentally Relevant Conditions  

EPA Science Inventory

The reported size distribution of silver nanoparticles (AgNPs) is strongly affected by the underlying measurement method, agglomeration state, and dispersion conditions. A selection of AgNP materials with vendor-reported diameters ranging from 1 nm to 100 nm, various size distrib...

289

Effects of environmental conditions on food consumption in female and male rats  

Microsoft Academic Search

The present experiment examined food and water consumption under different housing conditions in 20 female and 20 male Wistar rats. Food and water consumption were measured for 6 h a day following an 18-h same-sex crowded or individual housing period for each of 6 days. All subjects were individually housed during the 6-h measurement period and had access to food

Kelly J. Brown; Neil E. Grunberg

1996-01-01

290

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

291

Dehydration Kinetics of Pharmaceutical Hydrate: Effects of Environmental Conditions and Crystal Forms  

Microsoft Academic Search

The present study was conducted to investigate the influence of drying condition (atmospheric pressure with varying temperature, acetone vapor-induced environment, and vacuum pressure) on the dehydration kinetics of carbamazepine dihydrate. Samples were prepared in loose crystals and agglomerated forms. Increasing driving forces, that is, higher temperature (up to 60°C), low vacuum pressure (10 Torr), and the presence of acetone vapor pressure

Ji Yi Khoo; Daryl R. Williams; Jerry Y. Y. Heng

2010-01-01

292

The efficiency of cooperative banks: the impact of environmental economic conditions  

Microsoft Academic Search

This article analyses the cost and profit efficiencies of cooperative banks. Cooperative banks are small financial institutions providing financial services in several local geographical areas, and they play a fundamental role in various European banking systems. Even though these small financial institutions present a homogeneous business model, their performance is strongly influenced by the economic conditions of their local markets.

Francesca Battaglia; Vincenzo Farina; Franco Fiordelisi; Ornella Ricci

2010-01-01

293

Variability in the Environmental Factors Driving Evapotranspiration from a Grazed Rangeland during Severe Drought Conditions  

E-print Network

Severe Drought Conditions JOSEPH G. ALFIERI* AND PETER D. BLANKEN Department of Geography, University-half of the earth's terrestrial surface is susceptible to drought, which can have significant social, economic linking the land surface and atmosphere during drought. Using data collected during the International H2O

Blanken, Peter D.

294

ASSESSMENT OF FUNGAL GROWTH ON CEILING TILES UNDER ENVIRONMENTALLY CHARACTERIZED CONDITIONS  

EPA Science Inventory

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. he ability of fungi to grow on materials is well ...

295

Maternal sex effects and inbreeding depression under varied environmental conditions in gynodioecious Fragaria vesca subsp. bracteata  

PubMed Central

Background and Aims Gynodioecy (coexistence of females and hermaphrodites) is a sexual system that occurs in numerous flowering plant lineages. Thus, understanding the features that affect its maintenance has wide importance. Models predict that females must have a seed fitness advantage over hermaphrodites, and this may be achieved via seed quality or quantity. Females in a population of Fragaria vesca subsp. bracteata, a long-lived gynodioecious perennial, do not demonstrate a seed quantity advantage, so this study explored whether females produced better quality seed via maternal sex effects or avoidance of inbreeding depression (IBD). Methods Families of selfed and outcrossed seed were created using hermaphrodite mothers and families of outcrossed seed were created using female mothers. The effects of these pollination treatments were assessed under benign conditions early in life and under varied conditions later in life. To test for an effect of maternal sex, fitness components and traits associated with acclimation to variable environments of progeny of outbred hermaphrodites and females were compared. To test for expression of IBD, fitness parameters between inbred and outbred progeny of hermaphrodites were compared. Key Results Offspring of females were more likely to germinate in benign conditions and survive in harsh resource environments than outbred progeny of hermaphrodites. IBD was low across most life stages, and both the effect of maternal sex on progeny quality and the expression of IBD depended on both maternal family and resource condition of the progeny. Conclusions The effect of maternal sex and IBD on progeny quality depended on resource conditions, maternal lineage and progeny life stage. In conjunction with known lack of differences in seed quantity, the quality advantages and IBD observed here are still unlikely to be sufficient for maintenance of gynodioecy under nuclear inheritance of male sterility. PMID:23723257

Dalton, Rebecca M.; Koski, Matthew H.; Ashman, Tia-Lynn

2013-01-01

296

Section 3, Component 3: Control of Environmental Factors and Comorbid Conditions That Affect Asthma August 28, 2007  

E-print Network

Section 3, Component 3: Control of Environmental Factors and Comorbid Conditions That Affect Asthma THAT AFFECT ASTHMA K E Y P O I N T S : C O N T R O L O F E N V I R O N M E N T A L F A C T O R S A N D C O M O R B I D C O N D I T I O N S T H A T A F F E C T A S T H M A Exposure of patients who have asthma

Levin, Judith G.

297

High prevalence of campylobacter excretors among Liberian children related to environmental conditions.  

PubMed

Campylobacter was the bacterial pathogen most prevalent in 859 children, aged 6-59 months, examined in a house-to-house diarrhoea survey in two Liberian communities. 44.9% of the children from an urban slum and 28.4% from a rural area were excretors. Since the prevalence of diarrhoea was very high and consequently many convalescent carriers were found, it was not possible to evaluate the pathogenic role of campylobacter. The excretor rate increased with age and was significantly correlated to the use of supplementary feeding, inversely correlated to the quality of the water supply, and also associated with helminthic infestation. Results from re-examination of 172 children suggested a high intensity of transmission. The findings all indicate the existence of a heavy environmental contamination with campylobacter, probably of both human and animal faecal origin. PMID:3356221

Mølbak, K; Højlyng, N; Gaarslev, K

1988-04-01

298

Linking shoreline displacement to environmental conditions in the Wax Lake Delta, USA  

NASA Astrophysics Data System (ADS)

The dynamics of river deltas are not well-understood in part because of scarcity of historical data that document the growth or retreat of their channel networks, islands and shorelines. In particular, the mapping of deltaic shorelines is not trivial, however recent developments allow for their extraction from satellite and aerial imagery. Here, we present an analysis of environmental data and Landsat imagery of the Wax Lake Delta, a naturally-developing river delta in the shallow Atchafalaya Basin, Gulf of Mexico, USA. The image-based shoreline corresponds to the hydrodynamic shoreline, that is, the boundary of the subaerial and subaqueous portions of the delta, however, can be related to a morphodynamically-relevant shoreline by application of our method [Geleynse et al., 2012] to bathymetric-topographic data. Moreover, the effect of tides, river floods, wind, and vegetation cover on the extracted shorelines of the Wax Lake Delta can be identified.

Geleynse, N.; Hiatt, M. R.; Sangireddy, H.; Passalacqua, P.

2013-12-01

299

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

300

Methanogenesis control by employing various environmental stress conditions in two-chambered microbial fuel cells.  

PubMed

This study examines methanogen activity in microbial fuel cells when exposed to various environmental stresses, such as oxygen, low pH, low temperature, inhibitor (2-bromoethanesulfonate (BES)), and variations in external resistance. Controlling methanogenesis resulted in an increase in Coulombic efficiency (CE) because it was a major cause of electron loss. Methane was mainly produced from aceticlastic methanogenesis, rather than by syntrophic acetate oxidation, with Methanosarcinaceae being the primary contributor. Lowering the resistance from 600 to 50 Omega reduced the methanogenic electron loss by 24%; however, changing the temperature or pH level had little effect. A BES injection was the most potent strategy for the selective inhibition of methanogens without damaging exoelectrogens. The addition of 0.1-0.27 mM BES increased the CE from 35% to 70%. Oxygen stress successfully inhibited methanogens, while slightly suppressing the exoelectrogens, and is believed to be a practical option due to its low operating cost. PMID:20299209

Chae, Kyu-Jung; Choi, Mi-Jin; Kim, Kyoung-Yeol; Ajayi, F F; Park, Woosin; Kim, Chang-Won; Kim, In S

2010-07-01

301

Lifetime of Poly(triaryl amine) Based Organic Field Effect Transistors under Different Environmental Conditions  

NASA Astrophysics Data System (ADS)

Characterization of reliability and lifetime is a key issue on the way to commercialization of products based on organic electronics. Prediction of the lifetime requires the understanding of failure mechanisms and the circumstances leading to failure. In this work the stability of poly(triaryl amine) (PTAA) based organic field effect transistors (OFETs) on a poly(ethylene naphthalate) (PEN) substrate is investigated under environmental stressing. PTAA is known to form amorphous thin films after spin coating and to be air stable for extended periods of time. This inherent air stability makes it a good candidate for testing of environmental influences. The samples were electrically characterized regularly between storage cycles at 85 °C and 85 °C/85% relative humidity (RH). Samples stored under dry atmosphere and inert gas were used as reference. More than 1700 OFETs were produced in multiple batches and measured using an automated measurement system to collect statistically significant data. Circuit-relevant OFET parameters such as on- and off-current, mobility, threshold voltage and gate leakage current were extracted applying a thin film transistor (TFT) device model to the measured transfer and output curves. The threshold voltage is found to be the most sensitive parameter especially for the samples stored at 85 °C. The effect of storage under 85 °C/85%RH is observed to be comparably small. Fourier transform infrared (FT-IR) measurements of the aged OFET samples indicate a correlation between the shift of the electrical parameters and the appearance of carbonyl groups in the dielectric layer of the devices. Possible degradation mechanisms are discussed based on this observation.

Lau, Tobias; Lorenz, Enno; Koyuncu, Metin

2013-04-01

302

Challenges for physical characterization of silver nanoparticles under pristine and environmentally relevant conditions.  

PubMed

The reported size distribution of silver nanoparticles (AgNPs) is strongly affected by the underlying measurement method, agglomeration state, and dispersion conditions. A selection of AgNP materials with vendor-reported diameters ranging from 1 nm to 100 nm, various size distributions, and biocompatible capping agents including citrate, starch and polyvinylpyrrolidone were studied. AgNPs were diluted with either deionized water, moderately hard reconstituted water, or moderately hard reconstituted water containing natural organic matter. Rigorous physico-chemical characterization by consensus methods and protocols where available enables an understanding of how the underlying measurement method impacts the reported size measurements, which in turn provides a more complete understanding of the state (size, size distribution, agglomeration, etc.) of the AgNPs with respect to the dispersion conditions. An approach to developing routine screening is also presented. PMID:21416095

MacCuspie, Robert I; Rogers, Kim; Patra, Manomita; Suo, Zhiyong; Allen, Andrew J; Martin, Matthew N; Hackley, Vincent A

2011-05-01

303

Effect of Environmental Conditions on Growth of Alternaria alternata Causing Leaf Blight of Noni  

Microsoft Academic Search

Effect of different pH levels, temperature, light intensity and media were tested against the growth of A. alternata under in vitro conditions. The results of experiment indicated that the growth of A. alternata was maximum in pH range of 6.00- 6.50 and temperature range of 25 - 30°C. The exposure of the fungus to alternate cycles of 12 hour light

Manjunath Hubballi; Sevugapperumal Nakkeeran; Thiruvengadam Raguchander; Theerthagiri Anand; Ramasamy Samiyappan

2010-01-01

304

Effect of environmental conditions during heating on commercial spore strip performance.  

PubMed Central

Commercial biological indicator spore strips in glassine envelopes, produced by three manufacturers, were evaluated by fraction-negative procedures after being heated at 121.0 +/- 0.05 degrees C. Only one type of spore strip met the manufacturer's specifications. The strips of one manufacturer were further evaluated by fraction-negative and survivor curve-plate count procedures after being heated under several conditions (enclosed in glassine envelopes, in trypticase soy broth plus 0.0015% bromocresol purple, in Trypticase soy broth alone in Water for Injection, directly); Trypticase soy broth plus bromocresol purple and tryptic soy agar, respectively, were used as recovery media. The heating condition affected the D-value of the spore strip. Recovery procedures also had an effect; in all cases, the D-values obtained from the survivor curve tests were larger than those obtained from fraction-negative tests carried out under the same conditions. To determine if the differences in D-values between the two evaluation procedures were caused by the recovery media, we evaluated, by both methods, one type of spore strip heated directly and in glassine envelopes, using tryptic soy agar plus bromocresol purple and Trypticase soy broth plus 1.5% agar, respectively, as the recovery media. The survivor curve results showed that for both enclosed and unenclosed spore strips, there was a marked difference between the two recovery media; however, there was no difference when fraction-negative tests were used. PMID:7125646

Smith, G M; Kopelman, M; Jones, A; Pflug, I J

1982-01-01

305

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

PubMed

Casuarinas are very important plants for their various uses and survival in adverse sites or harsh environments. As nitrogen fixation, in symbiosis with Frankia, is an important factor for the survival of these plants under various conditions, the basis for selecting both effective and tolerant Frankia strains and Casuarina spp., are provided. Enhancement of the symbiotic relationship between Frankia and Casuarina, by mycorrhizal infection and other biofertilizing microorganisms such as Bacillus and Azospirillum, is reflected by superior plant growth. Casuarina leaf litter is also a great source for both inorganic and organic nutrients. Therefore, careful management of the top soil layer under Casuarina trees is very important. Litter decomposition ratio is affected by many physical chemical and biological factors including temperature, moisture conditions, lignin, and C-to-N and N-to-P ratios in addition to soil biota. In general, here the above relations are discussed and an alleviation model is presented for important disturbances of natural and human origin made in soil and environment, especially in the dry regions. In conclusion, we suggest how to optimize the nitrogen fixation and plant growth under the prevalent conditions. PMID:21448712

Sayed, W F

2011-01-01

306

Comparison of Environmental Conditions Between Offshore Sites in Europe and United States  

NASA Astrophysics Data System (ADS)

Siting of offshore wind turbines is dependent upon sound knowledge of met-ocean conditions. In addition to a sufficient description of the 3-D atmospheric wind field, a thorough analysis of the surface and sub-surface marine environment (that is, waves and currents) is also necessary to ensure a defensible choice of proper wind turbine and foundation infrastructure. Although hundreds of turbines of been deployed in the offshore waters of Europe, applying the characteristics of that environment to predict expected conditions in the U.S. (that is, the Atlantic, Gulf of Mexico, and Great Lakes marine environments) is at the very least inappropriate. For example, although northern European and U.S. offshore waters do experience similar intense extra-tropical cyclones responsible for high waves and wind, their frequency and local coastal morphology can produce vastly different wave and current responses. Furthermore, the U.S. east coast and Gulf of Mexico are subject to extreme wind and wave environments produced by tropical cyclones (i.e. hurricanes), storms that are notably absent from European waters. Here, we highlight the differences and similarities of met-ocean conditions for the offshore waters in Europe and the U.S. through a comparative analysis using historic observational and reanalysis data sets.

Freedman, J. M.; Filippelli, M. V.; Bailey, B. H.

2010-12-01

307

Physical demands of firefighter search and rescue in ambient environmental conditions.  

PubMed

This study investigated the physiological responses and limitations to a simulated search and rescue scenario in a high-rise building under ambient conditions. Sixteen firefighters performed the scenario under four conditions: standard duration breathing apparatus (SDBA) and 45 mm hose; extended duration breathing apparatus (EDBA) and 45 mm hose; SDBA and 70 mm hose; EDBA and 70 mm hose. Core temperature, skin temperature and heart rate were monitored. In four of 32 trials the casualty was rescued; the remainder of the trials were terminated for safety, high core temperature or shortage of air. Final core temperature and heart rate were higher in the EDBA (39.1 degrees C; 72% heart rate reserve (HRR)) than SDBA conditions (38.6 degrees C; 67%HRR). No differences were observed between hose sizes. The scenario proved too onerous to complete successfully in the majority of cases. Replacing SDBA with EDBA eliminates air supply as a limiting factor, but brings with it challenges of managing thermal strain. PMID:18568961

Richmond, V L; Rayson, M P; Wilkinson, D M; Carter, J M; Blacker, S D

2008-07-01

308

Degradation of methylene blue: optimization of operating condition through a statistical technique and environmental estimate of the treated wastewater.  

PubMed

FeO(x)-MoO(3)-P(2)O(5) (x=1 or 1.5) composite catalyst was prepared by solid reaction method and characterized by X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). Its catalytic activities on degradation of a heteropolyaromatic dye, methylene blue (MB), were also investigated under mild condition. In order to determine the optimum operating condition, the orthogonal experiments were devised. And the results revealed that initial concentration of MB was the key factor that affected the decoloration, while the catalysts dose has an insignificant effect. Environmental estimation was also done and the results showed that the treated wastewater have little influence on plant growth and could totally be applied to irrigation. PMID:17868986

Zhuo, Qiongfang; Ma, Hongzhu; Wang, Bo; Fan, Fang

2008-05-01

309

A commentary about the AMPHORA study: selected caveats, comments, and considerations about its conditions of diversity, uncertainty, and unpredictability.  

PubMed

This point-of-view commentary explores a selected range of issues relevant to alcoholic beverage drinking and nondrinking patterns documented by the AMPHORA European study which, with hind-sight, limits its generalizability, with fore-sight are generally inadequately considered and documented and, with ordinary insight, are not likely to affect the ongoing and future behaviors of policy making and sustaining stakeholders whatever their sources of influence and whatever the levels and quality of evidence-informed data, information, and derived knowledge. PMID:25014616

Einstein, S

2014-10-01

310

Abundance of Broad Bacterial Taxa in the Sargasso Sea Explained by Environmental Conditions but Not Water Mass  

PubMed Central

To explore the potential linkage between distribution of marine bacterioplankton groups, environmental conditions, and water mass, we investigated the factors determining the abundance of bacterial taxa across the hydrographically complex Subtropical Convergence Zone in the Sargasso Sea. Based on information from 16S rRNA gene clone libraries from various locations and two depths, abundances of the predominant taxa (eubacteria, Archaea, Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes, and the Roseobacter, SAR11, and SAR86 clades) were quantified by real-time PCR. In addition, the abundances of Synechococcus, Prochlorococcus, and picoalgae were determined by flow cytometry. Linear multiple-regression models determining the relative effects of eight environmental variables and of water mass explained 35 to 86% of the variation in abundance of the quantified taxa, even though only one to three variables were significantly related to any particular taxon's abundance. Most of the variation in abundance was explained by depth and chlorophyll a. The predominant phototrophs, Prochlorococcus and picoalgae, were negatively correlated with phosphate, whereas eubacteria, heterotrophic bacteria, and SAR86 were negatively correlated with nitrite. Water mass showed limited importance for explaining the abundance of the taxonomical groups (significant only for Roseobacter, explaining 14% of the variation). The results suggest the potential for predicting the abundance of broad bacterioplankton groups throughout the Sargasso Sea using only a few environmental parameters. PMID:24561593

Sjöstedt, Johanna; Martiny, Jennifer B. H.; Munk, Peter

2014-01-01

311

Environmental conditions during early life determine the consequences of inbreeding in Agrostemma githago (Caryophyllaceae).  

PubMed

In an inbred population, selection may reduce the frequency of deleterious recessive alleles through a process known as purging. Empirical studies suggest, however, that the efficacy of purging in natural populations is highly variable. This variation may be due, in part, to variation in the expression of inbreeding depression available for selection to act on. This experiment investigates the roles of life stage and early-life environment in determining the expression of inbreeding depression in Agrostemma githago. Four population-level crosses ('self', 'within', 'near' and 'far') were conducted on 20 maternal plants from a focal population. Siblings were planted into one of three early environmental treatments with varying stress levels. Within the focal population, evidence for purging of deleterious recessive alleles, as well as for variation in the expression of inbreeding depression across the life cycle was examined. In addition, the effect of early environment on the expression of inbreeding depression and the interaction with cross-type was measured. We find that deleterious recessive alleles have not been effectively purged from our focal population, the expression of inbreeding depression decreases over the course of the life cycle, and a stressful early environment reduces the variance in inbreeding depression expressed later in life, but does not consistently influence the relative fitness of inbred versus outcrossed individuals. PMID:23294449

Goodrich, S H; Beans, C M; Roach, D A

2013-03-01

312

Environmental Conditions in Water Storage Drums and Influences on Aedes aegypti inTrinidad, West Indies  

PubMed Central

Water storage drums are often a primary breeding site for Aedes aegypti in developing countries. Habitat characteristics can impact both adult and larval fitness and survival, which may potentially influence arbovirus transmission. Our objective was to compare fundamental environmental differences in water drums based on the presence or absence of larvae in Trinidad. Drums were categorized according to the larval status, and if the drum was constructed of steel or plastic. Water samples were analyzed for ammonium, nitrate, and soluble reactive phosphorus (SRP). Continuous surface water temperatures were also recorded. Nutrient concentrations were considerably lower than those reported for other container breeding mosquitoes. No nutrient measured differed in concentration between drums positive compared to those that were negative for the presence of Aedes aegypti larvae. Levels of SRP and ammonium in steel drums were significantly lower than in plastic water drums. Both maximum and minimum surface temperatures were significantly lower in drums positive for the presence of larvae than in drums without larvae. Water temperatures in March and May were warmer than during October sampling periods. Larval presence is likely dependent upon the interaction among multiple biotic and abiotic factors. Despite appearance, not all water storage drums are equally suitable for Aedes aegypti development. Exposing water storage drums to direct sunlight or increased heat may be used in conjunction with sealing containers to reduce production of Aedes aegypti when draining and chemical treatment are impractical. PMID:19539592

Hemme, Ryan R.; Tank, Jennifer L.; Chadee, Dave D.; Severson, David W.

2014-01-01

313

Galvanic protection distance of zinc coated steels under various environmental conditions  

SciTech Connect

Galvanic action between zinc and steel is an important property which 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 which 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. This paper reports the 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. [Cominco Product Technology Centre, Mississauga, Ontario (Canada)

1998-12-31

314

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

315

Acoustic noise in deep ice and environmental conditions at the South Pole  

E-print Network

To study the acoustic properties of the Antarctic ice the South Pole Acoustic Test Setup (SPATS) was installed in the upper part of drill holes for the IceCube neutrino observatory. An important parameter for the design of a future acoustic neutrino telescope is the acoustic background noise in the ice and its spatial and temporal variations. We study the absolute noise level depth profile from SPATS data and discuss systematic uncertainties. The measured noise is very stable over one year of data taking, and we estimate the absolute noise level to be acoustic neutrino detection projects in good weather conditions.

Timo Karg; for the IceCube Collaboration

2008-11-07

316

Biodegradation of aged diesel in diverse soil matrixes: impact of environmental conditions and bioavailability on microbial remediation capacity.  

PubMed

While bioremediation of total petroleum hydrocarbons (TPH) is in general a robust technique, heterogeneity in terms of contaminant and environmental characteristics can impact the extent of biodegradation. The current study investigates the implications of different soil matrix types (anthropogenic fill layer, peat, clay, and sand) and bioavailability on bioremediation of an aged diesel contamination from a heterogeneous site. In addition to an uncontaminated sample for each soil type, samples representing two levels of contamination (high and low) were also used; initial TPH concentrations varied between 1.6 and 26.6 g TPH/kg and bioavailability between 36 and 100 %. While significant biodegradation occurred during 100 days of incubation under biostimulating conditions (64.4-100 % remediation efficiency), low bioavailability restricted full biodegradation, yielding a residual TPH concentration. Respiration levels, as well as the abundance of alkB, encoding mono-oxygenases pivotal for hydrocarbon metabolism, were positively correlated with TPH degradation, demonstrating their usefulness as a proxy for hydrocarbon biodegradation. However, absolute respiration and alkB presence were dependent on soil matrix type, indicating the sensitivity of results to initial environmental conditions. Through investigating biodegradation potential across a heterogeneous site, this research illuminates the interplay between soil matrix type, bioavailability, and bioremediation and the implications of these parameters for the effectiveness of an in situ treatment. PMID:23242513

Sutton, Nora B; van Gaans, Pauline; Langenhoff, Alette A M; Maphosa, Farai; Smidt, Hauke; Grotenhuis, Tim; Rijnaarts, Huub H M

2013-07-01

317

Cytoprotective Effect of Short-Term Pretreatment with Proanthocyanidin on Human Gingival Fibroblasts Exposed to Harsh Environmental Conditions  

PubMed Central

Our previous study showed that exposing mouse fibroblasts to proanthocyanidin (PA) for only 1 min accelerated cell proliferation in a concentration-dependent manner. In this study, exposing human gingival fibroblasts (HGFs) to PA for 1 min similarly accelerated the proliferative response of the cells. Besides the accelerated proliferative response, PA showed a cytoprotective effect on HGFs exposed to harsh environmental conditions; short-term exposure of HGFs in the mitotic phase to pure water or physiological saline resulted in a lower recovery of viable cells. Pretreatment and concomitant treatment with PA improved the low recovery of cells exposed to pure water or physiological saline. In addition, HGFs exposed to PA for 1 min proliferated well even after being cultured in serum-free medium. In 100% confluent HGFs, being cultured in serum-free medium resulted in a high intracellular reactive oxygen species (ROS) level, but pretreatment with PA prevented the cells from increasing intracellular ROS. Thus, the results suggest that a short-term PA treatment exerts cytoprotective effects on HGFs exposed to harsh environmental conditions by improving the intracellular oxidative stress response. PMID:25405354

Kurauchi, Michiko; Niwano, Yoshimi; Shirato, Midori; Kanno, Taro; Nakamura, Keisuke; Egusa, Hiroshi; Sasaki, Keiichi

2014-01-01

318

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

2010-12-01

319

The unpredictability paradox: review of empirical comparisons of randomised and non-randomised clinical trials  

PubMed Central

Objective To summarise comparisons of randomised clinical trials and non-randomised clinical trials, trials with adequately concealed random allocation versus inadequately concealed random allocation, and high quality trials versus low quality trials where the effect of randomisation could not be separated from the effects of other methodological manoeuvres. Design Systematic review. Selection criteria Cohorts or meta-analyses of clinical trials that included an empirical assessment of the relation between randomisation and estimates of effect. Data sources Cochrane Review Methodology Database, Medline, SciSearch, bibliographies, hand searching of journals, personal communication with methodologists, and the reference lists of relevant articles. Main outcome measures Relation between randomisation and estimates of effect. Results Eleven studies that compared randomised controlled trials with non-randomised controlled trials (eight for evaluations of the same intervention and three across different interventions), two studies that compared trials with adequately concealed random allocation and inadequately concealed random allocation, and five studies that assessed the relation between quality scores and estimates of treatment effects, were identified. Failure to use random allocation and concealment of allocation were associated with relative increases in estimates of effects of 150% or more, relative decreases of up to 90%, inversion of the estimated effect and, in some cases, no difference. On average, failure to use randomisation or adequate concealment of allocation resulted in larger estimates of effect due to a poorer prognosis in non-randomly selected control groups compared with randomly selected control groups. Conclusions Failure to use adequately concealed random allocation can distort the apparent effects of care in either direction, causing the effects to seem either larger or smaller than they really are. The size of these distortions can be as large as or larger than the size of the effects that are to be detected. Key messagesEmpirical studies support using random allocation in clinical trials and ensuring that the allocation process is concealed—that is, that assignment is impervious to any influence by the people making the allocationThe effect of not using concealed random allocation can be as large or larger than the effects of worthwhile interventionsOn average, failure to use concealed random allocation results in overestimates of effect due to a poorer prognosis in non-randomly selected control groups compared with randomly selected control groups, but it can result in underestimates of effect, reverse the direction of effect, mask an effect, or give similar estimates of effectThe adequacy of allocation concealment may be a more sensitive measure of bias in clinical trials than scales used to assess the quality of clinical trialsIt is a paradox that the unpredictability of randomisation is the best protection against the unpredictability of the extent and direction of bias in clinical trials that are not properly randomised PMID:9794851

Kunz, Regina; Oxman, Andrew D

1998-01-01

320

Alternative life cycle strategies in the West African reed frog Hyperolius nitidulus : the answer to an unpredictable environment?  

Microsoft Academic Search

The West African reed frog Hyperolius nitidulus, mainly known for its extraordinary aestivation behaviour and physiology, is able to vary its reproductive strategy in response to environmental conditions. We found indirect as well as direct evidence for individuals not following the generally assumed one year-one generation life cycle including an extended aestivation phase during the dry season, but leading very

Kathrin P. Lampert; Eduard K. Linsenmair

2002-01-01

321

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

322

Control of environmental conditions at the lower boundary of field lysimeters  

NASA Astrophysics Data System (ADS)

Lysimeters are vessels containing disturbed or undisturbed soil, embedded completely in soil with its top even to the soil surface. At the bottom of lysimeters, the soil is cut off from the parent soil, and the lower boundary of lysimeters is usually exposed to atmospheric pressure. For this reason, soil water conditions may be different than of the surrounding soil. This may affect the soil-water conditions throughout the soil profile in comparison to the surrounding soil. To avoid this problem, lysimeters with a construction depth much more than the expected rooting depth should be used or a suction-controlled drainage system needs to be installed at the bottom of lysimeters. Not only the water flow but also the heat flow in the lysimeter is affected by the isolation of the soil and by the fact that the soil at the bottom of the lysimeter is cut off from the surrounding area. However, since now only a few studies have dealt with this issue. This is surprising because the soil thermal regime controls both growth and function of roots and shoots. Therefore, a new design for an automatic control of soil temperature at the lower boundary of large, undisturbed field lysimeters was developed. The objective of the intended talk is to present and evaluate the design and functionality of this new setup.

Schwärzel, Kai; Podlasly, Christian

2014-05-01

323

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

324

Organic-coated silver nanoparticles in biological and environmental conditions: fate, stability and toxicity.  

PubMed

This review paper presents the overview of processes involved in transformation of organic-coated silver nanoparticles (AgNPs) in biological systems and in the aquatic environment. The coating on AgNPs greatly influences the fate, stability, and toxicity of AgNPs in aqueous solutions, biological systems, and the environment. Several organic-coated AgNP systems are discussed to understand their stability and toxicity in biological media and natural water. Examples are presented to demonstrate how a transformation of organic-coated AgNPs in an aqueous solution is affected by the type of coating, pH, kind of electrolyte (mono- or divalent), ionic strength, organic ligands (inorganic and organic), organic matter (fulvic and humic acids), redox conditions (oxic and anoxic), and light. Results of cytotoxicity, genotoxicity, and ecotoxicity of coated AgNPs to food chain members (plants, bacteria, and aquatic and terrestrial organisms) are reviewed. Key factors contributing to toxicity are the size, shape, surface coating, surface charge, and conditions of silver ion release. AgNPs may directly damage the cell membranes, disrupt ATP production and DNA replication, alternate gene expressions, release toxic Ag(+) ion, and produce reactive oxygen species to oxidize biological components of the cell. A progress made on understanding the mechanism of organic-coated AgNP toxicity using different analytical techniques is presented. PMID:24406050

Sharma, Virender K; Siskova, Karolina M; Zboril, Radek; Gardea-Torresdey, Jorge L

2014-02-01

325

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

2009-03-01

326

Individual differences in impulsive and risky choice: effects of environmental rearing conditions.  

PubMed

The present experiment investigated early-rearing environment modulation of individual differences in impulsive and risky choice. Rats were reared in an isolated condition (IC; n=12), in which they lived alone without novel stimuli, or an enriched condition (EC; n=11), in which they lived among conspecifics with novel stimuli. The impulsive choice task involved choices between smaller-sooner (SS) versus larger-later (LL) rewards. The risky choice task involved choices between certain-smaller (C-S) versus uncertain-larger (U-L) rewards. Following choice testing, incentive motivation to work for food was measured using a progressive ratio task and correlated with choice behavior. HPLC analyses were conducted to determine how monoamine concentrations within the prefrontal cortex (PFC) and nucleus accumbens (NAC) related to behavior in different tasks. IC rats were more impulsive than EC rats, but they did not differ in risky choice behavior. However, choice behavior across tasks was significantly correlated (i.e., the more impulsive rats were also riskier). There were no group differences in monoamine levels, but noradrenergic and serotonergic concentrations were significantly correlated with impulsive and risky choice. Furthermore, serotonin and norepinephrine concentrations in the NAC significantly correlated with incentive motivation and the timing of the reward delays within the choice tasks. These results suggest a role for domain general processes in impulsive and risky choice and indicate the importance of the NAC and/or PFC in timing, reward processing, and choice behavior. PMID:24769268

Kirkpatrick, Kimberly; Marshall, Andrew T; Smith, Aaron P; Koci, Juraj; Park, Yoonseong

2014-08-01

327

Predictive physiological anticipation preceding seemingly unpredictable stimuli: a meta-analysis.  

PubMed

This meta-analysis of 26 reports published between 1978 and 2010 tests an unusual hypothesis: for stimuli of two or more types that are presented in an order designed to be unpredictable and that produce different post-stimulus physiological activity, the direction of pre-stimulus physiological activity reflects the direction of post-stimulus physiological activity, resulting in an unexplained anticipatory effect. The reports we examined used one of two paradigms: (1) randomly ordered presentations of arousing vs. neutral stimuli, or (2) guessing tasks with feedback (correct vs. incorrect). Dependent variables included: electrodermal activity, heart rate, blood volume, pupil dilation, electroencephalographic activity, and blood oxygenation level dependent (BOLD) activity. To avoid including data hand-picked from multiple different analyses, no post hoc experiments were considered. The results reveal a significant overall effect with a small effect size [fixed effect: overall ES?=?0.21, 95% CI?=?0.15-0.27, z?=?6.9, p??0.05) was conservatively calculated to be 87 reports. We explore alternative explanations and examine the potential linkage between this unexplained anticipatory activity and other results demonstrating meaningful pre-stimulus activity preceding behaviorally relevant events. We conclude that to further examine this currently unexplained anticipatory activity, multiple replications arising from different laboratories using the same methods are necessary. The cause of this anticipatory activity, which undoubtedly lies within the realm of natural physical processes (as opposed to supernatural or paranormal ones), remains to be determined. PMID:23109927

Mossbridge, Julia; Tressoldi, Patrizio; Utts, Jessica

2012-01-01

328

Predictive Physiological Anticipation Preceding Seemingly Unpredictable Stimuli: A Meta-Analysis  

PubMed Central

This meta-analysis of 26 reports published between 1978 and 2010 tests an unusual hypothesis: for stimuli of two or more types that are presented in an order designed to be unpredictable and that produce different post-stimulus physiological activity, the direction of pre-stimulus physiological activity reflects the direction of post-stimulus physiological activity, resulting in an unexplained anticipatory effect. The reports we examined used one of two paradigms: (1) randomly ordered presentations of arousing vs. neutral stimuli, or (2) guessing tasks with feedback (correct vs. incorrect). Dependent variables included: electrodermal activity, heart rate, blood volume, pupil dilation, electroencephalographic activity, and blood oxygenation level dependent (BOLD) activity. To avoid including data hand-picked from multiple different analyses, no post hoc experiments were considered. The results reveal a significant overall effect with a small effect size [fixed effect: overall ES?=?0.21, 95% CI?=?0.15–0.27, z?=?6.9, p??0.05) was conservatively calculated to be 87 reports. We explore alternative explanations and examine the potential linkage between this unexplained anticipatory activity and other results demonstrating meaningful pre-stimulus activity preceding behaviorally relevant events. We conclude that to further examine this currently unexplained anticipatory activity, multiple replications arising from different laboratories using the same methods are necessary. The cause of this anticipatory activity, which undoubtedly lies within the realm of natural physical processes (as opposed to supernatural or paranormal ones), remains to be determined. PMID:23109927

Mossbridge, Julia; Tressoldi, Patrizio; Utts, Jessica

2012-01-01

329

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. PMID:20664582

Wang, Wei; Sun, Dalong; Pan, Bin; Roberts, Christopher J; Sun, Xinglai; Hillard, Cecilia J; Liu, Qing-song

2010-01-01

330

Environmental effect on ABA concentration and water potential in olive leaves ( Olea europaea L. cv “Koroneiki”) under non-irrigated field conditions  

Microsoft Academic Search

How does the olive tree respond to environmental stress in the Mediterranean climate under non-irrigated field conditions with respect to leaf abscisic acid (ABA) concentrations and water status? To answer this question we determined simultaneously ABA concentration and water potential (?l) in olive leaves (Olea europaea L. cv “Koroneiki”) during three successive years and related them to environmental parameters. The

C. K. Kitsaki; J. B. Drossopoulos

2005-01-01

331

An explosive convective cloud system and its environmental conditions in MJO initiation observed during DYNAMO  

NASA Astrophysics Data System (ADS)

unusually large, explosive convective cloud system was observed over the equatorial Indian Ocean on 28 November 2011 during the DYNAMO (Dynamics of the Madden-Julian Oscillation (MJO)) field campaign. The significance of this mesoscale convective system (MCS) is its size and explosive development of cold cloud tops (-96°C) during the initiation of a strong MJO event. Observations from the DYNAMO show that the large MCS developed within a well-defined synoptic-scale cyclonic circulation associated with an equatorial low-pressure system with characteristics of a mixed Rossby-gravity wave that dominated the flow in the DYNAMO array. Prior to the development of the MCS, the equatorial flow was characterized by strong vertical wind shear with low-level westerlies and upper level easterlies. A region of decreased wind shear and enhanced upper level divergence emerged concurrently with the passage of the westward moving mixed Rossby-gravity wave-related low-pressure system and convective activity. In situ sounding observations suggest that widespread deep convection upstream of the large MCS may have contributed to the reduction of the upper level easterlies through vertical momentum transport and convective outflow. Both the reduction in vertical wind shear and enhanced low-level convergence induced by the equatorial low-pressure system created a favorable environment for the rapid development of the MCS. This study examines the development of the MCS and the associated synoptic-scale equatorial low-pressure system within the large-scale MJO circulation using in situ sounding observations from DYNAMO, which provide new insights into the interaction between convection and environmental flow during MJO initiation over the equatorial Indian Ocean.

Judt, Falko; Chen, Shuyi S.

2014-03-01

332

Environmental conditions and biotic interactions influence ecosystem structure and function in a drying stream  

USGS Publications Warehouse

Benthic consumers influence stream ecosystem structure and function, but these interactions depend on environmental context. We experimentally quantified the effects of central stoneroller minnows (Campostoma anomalum (Rafinesque) and Meek's crayfish (Orconectes meeki meeki (Faxon)) on benthic communities using electric exclusion quadrats in Little Mulberry Creek before (June) and during (August) seasonal stream drying. Unglazed ceramic tiles were deployed in June and August to measure periphyton and invertebrate abundance, and leafpack decomposition and primary production were also measured in August. Relationships between stoneroller and crayfish density and the size of consumer effects were evaluated with multiple linear regression models. Average chlorophyll a abundance was greater on exposed than exclusion tiles in August, but not in June. Sediment dry mass, periphyton ash-free dry mass (AFDM), and chironomid densities on tiles did not differ among treatments in either period. Leaf packs decayed faster in exposed than exclusion treatments (kexposed = 0.038 ?? 0.013, kexclusion = 0.007 ?? 0.002), but consumer effects were stronger in some pools than others. Leafpack invertebrate biomass and abundance and tile primary productivity did not differ among treatments. Consumer effects on chlorophyll a were related to crayfish and stoneroller density, and effects on chironomid density were related to stoneroller density. These results contrast with a previous exclusion experiment in Little Mulberry Creek that demonstrated strong consumer effects. The influence of stream drying on consumer effects appears to have been reduced by strong spates, underscoring the importance of conducting multi-year studies to determine the magnitude of variability in ecological interactions. ?? US Government: USGS 2010.

Ludlam, J.P.; Magoulick, D.D.

2010-01-01

333

Distribution of Recent Benthic Foraminifera and its Environmental Conditions of Karaikal, Central Coast of Tamil Nadu  

NASA Astrophysics Data System (ADS)

Foraminifera have been successful inhabitants of every aquatic environment from deep oceans to brackish water lagoons, estuaries and even rarely in freshwater streams, lakes etc. offshore region of Karaikal the present study has been taken up to enhance the existing knowledge on foraminifera of central coast of Tamil Nadu, India. Totally 21 sediment and water samples were collected from the offshore region. The depth of sample collection in offshore area ranges from 1.5 m to 12 m. Standard procedures adopted for the evaluation of different environmental parameters are incorporated. A total of 33 foraminiferal taxa belonging to 17 genera, 12 subfamilies, 14 superfamilies, and 4 suborders have been identified. In Karaikal , the mean size of the sediments on the foreshore ranges from 1.51 to 2.95 ? indicating the predominance of fine sediments (80-85%) with an admixture of medium-grained sands. Calcium carbonate content is generally found to be directly proportional to the population size in both the estuary and shelf area. It clearly indicates that due to the erosional activities whatever sediments deposited near the Arasalar river in that region are transported to the marine region and were drifted towards northern direction by longshore current, hence the deposition of carbonate in the sediments shows negative correlation. Due to strong high energy environment the current action is more in this region the juvinile forms of A. beccarri, A.tepida, A. dendata, E. crispum, P. calar, and P. nipponica only withstand and the other species are absent. The Correlation between Living vs Dead, Dead Vs Calcium carbonate, Salinity Vs living, Organic matter Vs Living, Organic matter Vs Carbonate content shows positive correlation for all the samples like LT, HT, Beach, River, and Offshore. Even though, all the ecological parameters having good correlation with foraminifera, but the distribution are very less in the study area. M.RAJA Dept.of.Geology University of Madras Chennai,Tamilnadu, INDIA.

Murugan, R.; Gandhi, S.

2013-05-01

334

Relationship between suicide and myocardial infarction with regard to changing physical environmental conditions  

NASA Astrophysics Data System (ADS)

In recent years, the possible association of changes in mortality from cardiovascular disease and myocardial infarction (MI) and deaths related to violence and the suicide rate has been repeatedly discussed. This study examined the relationship between cosmic physical changes (solar, geomagnetic and other space activity parameters) and changes in the total number of in-hospital and MI-related deaths and deaths from suicide to determine if a relationship exists between the distribution of total and MI-related deaths with suicide over time; some differences in the serotonergic mechanisms involved in the pathogenesis of MI and suicide were also taken into account. All suicides ( n=2359) registered in the State of Israel from 1981 to 1989 (108 months) were analysed and compared with the total number of deaths ( n=15601) and deaths from MI ( n=1573) in a large university hospital over 180 months (1974 1989). The following were the main features of the Results. (1) Monthly suicide rate was correlated with space proton flux ( r=0.42, P=0.0001) and with geomagnetic activity ( r=-0.22, P=0.03). (2) Total hospital and MI-related deaths were correlated with solar activity parameters ( r=0.35, P<0.001) and radiowave propagation ( r=0.52-0.44, P<0.001), an with proton flux ( r=-0.3 to -0.26, P<0.01). (3) Monthly suicide distribution over 108 months was correlated with MI ( r=-0.33, P=0.0005) and total hospital mortality ( r=-0.22, P=0.024). (4) Gender differences were prominent. We conclude that the monthly distributions of suicides and deaths from MI are adversely related to many environmental physical parameters and negatively correlated with each other.

Stoupel, Eliahu; Abramson, Eugeny; Sulkes, Jaqueline; Martfel, Joseph; Stein, Nechama; Handelman, Meir; Shimshoni, Michael; Zadka, Pnina; Gabbay, Uri

1995-12-01

335

Environmental conditions and characteristics of ice supersaturated regions from global field campaigns  

NASA Astrophysics Data System (ADS)

Cirrus clouds play important roles in the Earth's climate and weather and their influences extend from the global scale (~30% coverage of the Earth's surface) to the microscale (e.g., interactions with aerosols). Cirrus cloud formation occurs in ice supersaturated regions (ISSRs), where the relative humidity with respect to ice (RHi) is greater than 100%. Recent observations show that cirrus clouds have a very small (~1 km) horizontal median length, yet the origin of such small scale structure is not known. The magnitude of cirrus clouds' radiative forcing is greatly influenced by cloud properties such as the coverage, thickness, ice crystal number concentration and size distribution. The microscale structure of ISSRs is critical for the microphysical processes in cirrus clouds, since the local conditions of ISSRs (e.g. temperature and RHi) influence the properties of ice crystals and their interactions with aerosols. However, the spatial structure of ISSRs and its controlling factors are still unknown below the mesoscale. To this end, we analyzed the spatial structure and environments of ISSRs — the prerequisite stage of cirrus cloud formation — based on in situ, high resolution (1 Hz, ~230 m) aircraft observations from 87°N to 67°S from five different field campaigns that span the tropics, mid-latitudes, and polar regions: NSF START08, HIPPO 1-5, PREDICT, TORERO, and DC3 field campaigns. By analyzing a large number (>7000) of individual case studies of ice supersaturated regions, we reveal the patchy nature of ISSRs with their median lengths being very small (~ 1 km) regardless of the location. The patchiness of ISSRs is found to largely correlate with water vapor (H2O) spatial heterogeneities, while the correlations with temperature (T) and vertical velocity (w) heterogeneities are much less dominant. The large influence of H2O heterogeneities on ISSR patchiness not only happens in supersaturated conditions but also extends to subsaturated conditions. The dominance of H2O over the spatial relative humidity field holds from the microscale (~230 m) to the mesoscale (~120 km) over various ranges of temperature (205-302K), water vapor (2-39,000 ppmv) and pressure (133-1,014 hPa). These findings suggest that H2O heterogeneities play crucial roles in determining the RHi spatial heterogeneities even before ISSRs are formed. Neglecting H2O heterogeneities in simplified ISSR evolution schemes results in different ISSR structures than those observed, which in turn changes the predicted properties of cirrus clouds.

Zondlo, M. A.; Diao, M.; Zhang, Q.; DiGangi, J.; O'Brien, A.

2012-12-01

336

Formation of Martian Gullies by the Action of Liquid Water Flowing Under Current Martian Environmental Conditions  

NASA Technical Reports Server (NTRS)

Images from the Mars Orbiter Camera (MOC) on the Mars Global Surveyor (MGS) spacecraft show geologically young small-scale features resembling terrestrial water-carved gullies. An improved understanding of these features has the potential to reveal important information about the hydrological system on Mars, which is of general interest to the planetary science community as well as the field of astrobiology and the search for life on Mars. The young geologic age of these gullies is often thought to be a paradox because liquid water is unstable at the Martian surface. Current temperatures and pressures are generally below the triple point of water (273 K, 6.1 mbar) so that liquid water will spontaneously boil and/or freeze. We therefore examine the flow of water on Mars to determine what conditions are consistent with the observed features of the gullies.

Heldmann, J. L.; Toon, O. B.; Pollard, W. H.; Mellon, M. T.; Pitlick, J.; McKay, C. P.; Andersen, D. T.

2005-01-01

337

Effects of environmental conditions on xylose fermentation by recombinant Escherichia coli.  

PubMed Central

In batch fermentations, optimal conversion of xylose to ethanol by recombinant Escherichia coli was obtained under the following conditions: 30 to 37 degrees C, pH 6.4 to 6.8, 0.1 to 0.2 M potassium phosphate buffer, and xylose concentrations of 8% or less. A yield of 39.2 g of ethanol per liter (4.9% ethanol by volume) was observed with 80 g of xylose per liter, equivalent to 96% of the maximum theoretical yield. Maximal volumetric productivity was 0.7 g of ethanol per liter per h in batch fermentations and 30 g of ethanol per liter per h in concentrated cell suspensions (analogous to cell recycling). PMID:2407186

Ohta, K; Alterthum, F; Ingram, L O

1990-01-01

338

Cultural methods and environmental conditions affecting gray mold and its management in lisianthus.  

PubMed

Gray mold, caused by Botrytis cinerea, severely affects the base of the stems of lisianthus (Eustoma grandiflorum) plants as well as the cut stems left after flowers are harvested. This study examined infection of lisianthus plants by B. cinerea under laboratory and commercial greenhouse production conditions typical for Israel and evaluated cultural methods for manipulating disease development in commercial greenhouses. Although the lower nodes of lisianthus stems are typically infected, in this study, the inherent susceptibility of these nodes was less than that of nodes midway up the stem. Greater light intensity (4,860 lux) was associated with significantly more severe stem wounds than lower light intensities of 140 to 1,020 lux. Lower light intensity (140 lux) was associated with significantly more severe leaf infection. The development of gray mold along leaves toward the stem was slower at 26 degrees C than at 18 to 20 degrees C and was fastest at relative humidity (RH) levels close to saturation (>99%). B. cinerea infection developed in all stem wounds exposed to 65 to 99% RH and at temperatures of 12 to 29 degrees C. Infection severity in stem wounds (measured as lesion length) on whole plants was significantly less at 26 degrees C than at 18 or 22 degrees C, and was significantly higher at 99% RH compared with 70 to 85 and 85 to 95% RH. Severity of gray mold was the greatest at 15 to 22 degrees C and 85 to 99% RH. Under commercial greenhouse conditions, supplemental calcium (Ca(NO3)2) applied in fertigation or as a spray led to moderate yet significant reduction in disease severity. In addition, polyethylene soil cover and the use of buried drip irrigation instead of surface drip irrigation suppressed gray mold significantly on cut stems following harvest. Covering the soil with polyethylene also suppressed gray mold significantly as compared with the common practice of growing lisianthus in bare soil. PMID:19351252

Shpialter, Lena; David, Dalia Rav; Dori, Irit; Yermiahu, Uri; Pivonia, Shimon; Levite, Rahel; Elad, Yigal

2009-05-01

339

Fish otolith geochemistry, environmental conditions and human occupation at Lake Mungo, Australia  

NASA Astrophysics Data System (ADS)

Fish otoliths from the Willandra Lakes Region World Heritage Area (south-western New South Wales, Australia) have been analysed for oxygen isotopes and trace elements using in situ techniques, and dated by radiocarbon. The study focused on the lunettes of Lake Mungo, an overflow lake that only filled during flooding events and emptied by evaporation, and Lake Mulurulu, which was part of the running Willandra Creek system. Samples were collected from two different contexts: from hearths directly associated with human activity, and isolated surface finds. AMS radiocarbon dating constrains the human activity documented by five different hearths to a time span of less than 240 years around 19,350 cal. BP. These hearths were constructed in aeolian sediments with alternating clay and sand layers, indicative of fluctuating lake levels and occasional drying out. The geochemistry of the otoliths confirms this scenario, with shifts in Sr/Ca and Ba/Ca marking the entry of the fish into Lake Mungo several years before their death, and a subsequent increase in the ?18O by ˜4‰ indicating increasing evaporation of the lake. During sustained lake-full conditions there are considerably fewer traces of human presence. It seems that the evaporating Lake Mungo attracted people to harvest fish that might have become sluggish through oxygen starvation in an increasingly saline water body (easy prey hypothesis). In contrast, surface finds have a much wider range in radiocarbon age as a result of reworking, and do not necessarily indicate evaporative conditions, as shown by comparison with otoliths from upstream Lake Mulurulu.

Long, Kelsie; Stern, Nicola; Williams, Ian S.; Kinsley, Les; Wood, Rachel; Sporcic, Katarina; Smith, Tegan; Fallon, Stewart; Kokkonen, Harri; Moffat, Ian; Grün, Rainer

2014-03-01

340

Effects of environmental conditions on onset of xylem growth in Pinus sylvestris under drought.  

PubMed

We determined the 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 2007-10 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 sites, 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 site and 205 ± 36 DD at the dry-mesic site. Temperature sums calculated from spring equinox until onset of xylem growth showed somewhat less variability during the 4-year study period, amounting to 144 ± 10 and 137 ± 12 DD at the xeric and dry-mesic sites, 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 a dry inner Alpine climate, the results of this study revealed that (i) a daily minimum air temperature threshold for onset of xylem growth in the range 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. PMID:21593011

Swidrak, Irene; Gruber, Andreas; Kofler, Werner; Oberhuber, Walter

2011-05-01

341

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. PMID:21593011

Swidrak, Irene; Gruber, Andreas; Kofler, Werner; Oberhuber, Walter

2012-01-01

342

Marine cold seeps and their manifestations: geological control, biogeochemical criteria and environmental conditions  

NASA Astrophysics Data System (ADS)

Characteristics of cold seeps at different geologic settings are the subject of this review primarily based on results of the Research Consortium SFB 574. Criteria are drawn from examples on the erosive convergent margin off Costa Rica, the accretionary margin off Chile supplemented by examples from the transform margin of the Golf of Cadiz and the convergent Hikurangi margin off New Zealand. Others are from well-studied passive margins of the Black Sea, the Golf of Mexico, the eastern Mediterranean Sea and the South China Sea. Seeps at all settings transport water and dissolved compounds to the ocean through the seafloor by different forcing mechanism and from different depths of the submerged geosphere (10s of meters to 10s of km). The compounds sustain oasis-type ecosystems by providing bioactive reductants sulfide, methane and hydrogen. Hereby, the interaction between fluid composition, flux rates and biota results in a diagnostic hydrocarbon-metazoan-microbe-carbonate association; currently, well over 100 active sites are known. The single most important reaction is microbially mediated anaerobic oxidation of methane with secondary reactions involving S-biogeochemistry and carbonate mineral precipitation. Seep fluids and their seafloor manifestations provide clues as to source depth, fluid-sediment/rock interaction during ascent, lifetime and cyclicity of seepage events but less so on the magnitude of return flow. At erosive margins, Cl-depleted and B-enriched fluids from clay dehydration provide criteria for source depth and temperature. The upward material flow generates mud volcanoes at the seafloor above the projected location of dehydration at depth. At accretionary margins, fluids are derived from more shallow depths by compaction of sediments as they ride on the incoming oceanic plate; they are emitted through thrust faults. At highly sedimented margins, organic-rich and evaporite-containing strata (when present) determine the final fluid composition, by emitting characteristically gas hydrate-derived methane, brine-associated non-methane hydrocarbons or leached elements and their isotopes (Li, ?7Li, B, Ba) from host sediments. Smectite-illite transformation and associated Cl-depletion from release of interlayer water is a pervasive process at these margins. Rare earth element pattern in conjunction with redox-sensitive metals retained in seep carbonates indicate whether or not they precipitated in contact with oxic bottom water or suboxic fluids; clear environmental characterization, though, currently remains inconclusive. More deeply sourced fluids as in transform margins may be characterized by their 87Sr/86Sr ratios from interaction with oceanic crustal rocks below. Quantification of flow and reliable estimates of total volatile output from fore-arcs remain a challenge to seep research, as does understanding the role of geologically derived methane in the global methane cycle.

Suess, Erwin

2014-10-01

343

Seasonal variations in microbial populations and environmental conditions in an extreme acid mine drainage environment.  

PubMed

Microbial populations, their distributions, and their aquatic environments were studied over a year (1997) at an acid mine drainage (AMD) site at Iron Mountain, Calif. Populations were quantified by fluorescence in situ hybridizations with group-specific probes. Probes were used for the domains Eucarya, Bacteria, and Archaea and the two species most widely studied and implicated for their role in AMD production, Thiobacillus ferrooxidans and Leptospirillum ferrooxidans. Results show that microbial populations, in relative proportions and absolute numbers, vary spatially and seasonally and correlate with geochemical and physical conditions (pH, temperature, conductivity, and rainfall). Bacterial populations were in the highest proportion (>95%) in January. Conversely, archaeal populations were in the highest proportion in July and September ( approximately 50%) and were virtually absent in the winter. Bacterial and archaeal populations correlated with conductivity and rainfall. High concentrations of dissolved solids, as reflected by high conductivity values (up to 125 mS/cm), occurred in the summer and correlated with high archaeal populations and proportionally lower bacterial populations. Eukaryotes were not detected in January, when total microbial cell numbers were lowest (<10(5) cells/ml), but eukaryotes increased at low-pH sites ( approximately 0.5) during the remainder of the year. This correlated with decreasing water temperatures (50 to 30 degrees C; January to November) and increasing numbers of prokaryotes (10(8) to 10(9) cells/ml). T. ferrooxidans was in highest abundance (>30%) at moderate pHs and temperatures ( approximately 2.5 and 20 degrees C) in sites that were peripheral to primary acid-generating sites and lowest (0 to 5%) at low-pH sites (pH approximately 0.5) that were in contact with the ore body. L. ferrooxidans was more widely distributed with respect to geochemical conditions (pH = 0 to 3; 20 to 50 degrees C) but was more abundant at higher temperatures and lower pHs ( approximately 40 degrees C; pH approximately 0.5) than T. ferrooxidans. PMID:10427059

Edwards, K J; Gihring, T M; Banfield, J F

1999-08-01

344

Dose-dependent effects of caffeine on behavior and thermoregulation in a chronic unpredictable stress model of depression in rats  

Microsoft Academic Search

The effects of the non-selective adenosine A1\\/A2 receptor antagonist caffeine on behavior and thermoregulation in chronic unpredictable stress (CUS) model of depression was studied in Wistar rats. In the open field (OF) test, caffeine dose-dependently increased motor activity while decreased grooming and time spent in the corner. Five-week exposure to CUS procedure had the opposite effect in rats. Caffeine reversed

D. Pechlivanova; J. Tchekalarova; R. Nikolov; K. Yakimova

2010-01-01

345

An experimental study on the aggregation of TiO2 nanoparticles under environmentally relevant conditions.  

PubMed

The eventual future scenario of a release of nanomaterials into the environment makes it necessary to assess the risk involved in their use by studying their behavior in natural waters. NanoTiO2 is one of the most commonly employed nanomaterials. In the present work we studied the aggregation rates, aggregate size and aggregate morphology of NanoTiO2 under the presence of inert electrolytes, divalent cations, and these two combined with natural organic matter, in an effort to provide a comprehensive investigation of the phenomena of interaction of nanomaterials and natural waters and elucidate some of the conflicting information reported in the literature. The stability of nanoparticles could be explained in all cases, at least qualitatively, in terms of classical DLVO interactions (Electrical Double Layer, Van der Waals). Divalent cations were adsorbed to the surface of the nanoparticles, neutralizing the negative charge at pH values greater than the point of zero charge and inducing aggregation. Natural organic matter (NOM) adsorbed to the particles and made their zeta potential more negative, hence stabilizing them by lowering the pH of maximum aggregation. Divalent cations partially neutralized the adsorbed NOM, and at high concentrations aggregation was observed with Ca(2+) but not Mg(2+), suggesting the presence of specific Ca(2+)-NOM bridges. SEM images visually revealed a fractal-like morphology of the aggregates formed under unfavorable conditions. PMID:23579091

Romanello, Marina Belen; Fidalgo de Cortalezzi, Maria M

2013-08-01

346

Chromium (VI) remediation by a native strain: effect of environmental conditions and removal mechanisms involved.  

PubMed

A native bacterial strain with high capability for Cr (VI) removal was isolated from tannery sediments located in Elena (Córdoba Province, Argentina). The strain was characterized by amplification of 16S rRNA gene and identified as Serratia sp. C8. It was able to efficiently remove different Cr (VI) concentrations in a wide range of pHs and temperatures. The addition of different carbon sources as well as initial inoculum concentration were analyzed, demonstrating that Serratia sp. C8 could reduce 80 % of 20 mg/L Cr (VI) in a medium containing glucose 1 g/L, at pH 6-7 and 28 °C as optimal conditions, using 5 % inoculum concentration. The mechanisms involved in Cr (VI) removal were also evaluated. The strain was capable of biosorpting around 7.5-8.5 % of 20 mg/L Cr on its cell surface and to reduce Cr (VI). In addition, approximately a 54 and 46 % of total Cr was detected in the biomass and in the culture medium, respectively, and in the culture medium, Cr (III) was the predominant species. In conclusion, Serratia sp. C8 removed Cr (VI) and the mechanisms involved in decreasing order of contribution were as follows: reduction catalyzed by intracellular enzymes, accumulation into the cells, and biosorption to the microbial biomass. This strain could be a suitable microorganism for Cr (VI) bioremediation of tannery sediments and effluents or even for other environments contaminated with Cr. PMID:25023657

González, Paola S; Ambrosio, Laura F; Paisio, Cintia E; Talano, Melina A; Medina, María I; Agostini, Elizabeth

2014-12-01

347

Unique picoeukaryotic algal community under multiple environmental stress conditions in a shallow, alkaline pan.  

PubMed

Winter phytoplankton communities in the shallow alkaline pans of Hungary are frequently dominated by picoeukaryotes, sometimes in particularly high abundance. In winter 2012, the ice-covered alkaline Zab-szék pan was found to be extraordinarily rich in picoeukaryotic green algae (42-82 × 10(6) cells ml(-1)) despite the simultaneous presence of multiple stressors (low temperature and light intensity with high pH and salinity). The maximum photosynthetic rate of the picoeukaryote community was 1.4 ?g C ?g chlorophyll a (-1) h(-1) at 125 ?mol m(-2) s(-1). The assimilation rates compared with the available light intensity measured on the field show that the community was considerably light-limited. Estimated areal primary production was 180 mg C m(-2) d(-1). On the basis of the 18S rRNA gene analysis (cloning and DGGE), the community was phylogenetically heterogeneous with several previously undescribed chlorophyte lineages, which indicates the ability of picoeukaryotic communities to maintain high genetic diversity under extreme conditions. PMID:24281914

Pálffy, Károly; Felföldi, Tamás; Mentes, Anikó; Horváth, Hajnalka; Márialigeti, Károly; Boros, Emil; Vörös, Lajos; Somogyi, Boglárka

2014-01-01

348

Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions.  

PubMed

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 nonlinear 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 degrees C and 50 degrees 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. PMID:11594634

Fiala, D; Lomas, K J; Stohrer, M

2001-09-01

349

Reverse-engineering the Arabidopsis thaliana transcriptional network under changing environmental conditions  

PubMed Central

Background Understanding the molecular mechanisms plants have evolved to adapt their biological activities to a constantly changing environment is an intriguing question and one that requires a systems biology approach. Here we present a network analysis of genome-wide expression data combined with reverse-engineering network modeling to dissect the transcriptional control of Arabidopsis thaliana. The regulatory network is inferred by using an assembly of microarray data containing steady-state RNA expression levels from several growth conditions, developmental stages, biotic and abiotic stresses, and a variety of mutant genotypes. Results We show that the A. thaliana regulatory network has the characteristic properties of hierarchical networks. We successfully applied our quantitative network model to predict the full transcriptome of the plant for a set of microarray experiments not included in the training dataset. We also used our model to analyze the robustness in expression levels conferred by network motifs such as the coherent feed-forward loop. In addition, the meta-analysis presented here has allowed us to identify regulatory and robust genetic structures. Conclusions These data suggest that A. thaliana has evolved high connectivity in terms of transcriptional regulation among cellular functions involved in response and adaptation to changing environments, while gene networks constitutively expressed or less related to stress response are characterized by a lower connectivity. Taken together, these findings suggest conserved regulatory strategies that have been selected during the evolutionary history of this eukaryote. PMID:19754933

Carrera, Javier; Rodrigo, Guillermo; Jaramillo, Alfonso; Elena, Santiago F

2009-01-01

350

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

351

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

352

Efficiency of different sanitation methods on Listeria monocytogenes biofilms formed under various environmental conditions.  

PubMed

The resistance of Listeria monocytogenes biofilms formed under food processing conditions, against various sanitizing agents and disinfection procedures was evaluated in the present study. The first sanitation procedure included biofilm formation on stainless steel coupons (SS) placed in tryptic soy broth supplemented with 0.6% yeast extract (TSBYE) of various concentrations of NaCl (0.5, 7.5 and 9.5%) at different temperatures (5 and 20 °C). The biofilms formed were exposed to warm (60 °C) water for 20 min, or to peroxyacetic acid (2% PAA) for 1, 2, 3 and 6 min. Treatment with warm water caused no significant (P ? 0.05) reductions in the attached populations. Conversely, surviving bacteria on SS coupons decreased as the exposure time to 2% PAA increased and could not be detected by culture after 6 min of exposure. Biofilms formed at 20°C were more resistant to PAA than biofilms formed at 5 °C. Salt concentration in the growth medium had no marked impact on the resistance to PAA. The second sanitation procedure included biofilm formation of nonadapted (NA) and acid-adapted (AA) cells in TSBYE of pH 5.0 and 7.0 (i.e., NA-5.0, NA-7.0 and AA-5.0, AA-7.0) at 4 °C. Coupons bearing attached cells of L. monocytogenes were periodically exposed to chlorine (0.465% Cl(-)), quaternary ammonium compound (1% QAC) and 2% PAA. The resistance of attached cells to QAC, PAA and Cl(-) followed the order: AA-5.0>NA-7.0 ? AA-7.0>NA-5.0. The most effective sanitizer was QAC followed by PAA and Cl(-). The results can lead to the development of efficient sanitation strategies in order to eliminate L. monocytogenes from the processing environment. Furthermore, such results may explain the presence of L. monocytogenes after sanitation as a result of cell attachment history. PMID:21093085

Belessi, Charalambia-Eirini A; Gounadaki, Antonia S; Psomas, Antonios N; Skandamis, Panagiotis N

2011-03-01

353

Precision and accuracy of spectrophotometric pH measurements at environmental conditions in the Baltic Sea  

NASA Astrophysics Data System (ADS)

The increasing uptake of anthropogenic CO2 by the oceans has raised an interest in precise and accurate pH measurement in order to assess the impact on the marine CO2-system. Spectrophotometric pH measurements were refined during the last decade yielding a precision and accuracy that cannot be achieved with the conventional potentiometric method. However, until now the method was only tested in oceanic systems with a relative stable and high salinity and a small pH range. This paper describes the first application of such a pH measurement system at conditions in the Baltic Sea which is characterized by a wide salinity and pH range. The performance of the spectrophotometric system at pH values as low as 7.0 (“total” scale) and salinities between 0 and 35 was examined using TRIS-buffer solutions, certified reference materials, and tests of consistency with measurements of other parameters of the marine CO2 system. Using m-cresol purple as indicator dye and a spectrophotometric measurement system designed at Scripps Institution of Oceanography (B. Carter, A. Dickson), a precision better than ±0.001 and an accuracy between ±0.01 and ±0.02 was achieved within the observed pH and salinity ranges in the Baltic Sea. The influence of the indicator dye on the pH of the sample was determined theoretically and is presented as a pH correction term for the different alkalinity regimes in the Baltic Sea. Because of the encouraging tests, the ease of operation and the fact that the measurements refer to the internationally accepted “total” pH scale, it is recommended to use the spectrophotometric method also for pH monitoring and trend detection in the Baltic Sea.

Hammer, Karoline; Schneider, Bernd; Kuli?ski, Karol; Schulz-Bull, Detlef E.

2014-06-01

354

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. PMID:22737147

Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

2012-01-01

355

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

356

Physiology of Geobacter metallireducens under excess and limitation of electron donors. Part II. Mimicking environmental conditions during cultivation in retentostats.  

PubMed

The strict anaerobe Geobacter metallireducens was cultivated in retentostats under acetate and acetate plus benzoate limitation in the presence of Fe(III) citrate in order to investigate its physiology under close to natural conditions. Growth rates below 0.003h(-1) were achieved in the course of cultivation. A nano-liquid chromatography-tandem mass spectrometry-based proteomic approach (nano-LC-MS/MS) with subsequent label-free quantification was performed on proteins extracted from cells sampled at different time points during retentostat cultivation. Proteins detected at low (0.002h(-1)) and high (0.06h(-1)) growth rates were compared between corresponding growth conditions (acetate or acetate plus benzoate). Carbon limitation significantly increased the abundances of several catabolic proteins involved in the degradation of substrates not present in the medium (ethanol, butyrate, fatty acids, and aromatic compounds). Growth rate-specific physiology was reflected in the changed abundances of energy-, chemotaxis-, oxidative stress-, and transport-related proteins. Mimicking natural conditions by extremely slow bacterial growth allowed to show how G. metallireducens optimized its physiology in order to survive in its natural habitats, since it was prepared to consume several carbon sources simultaneously and to withstand various environmental stresses. PMID:24736031

Marozava, Sviatlana; Röling, Wilfred F M; Seifert, Jana; Küffner, Robert; von Bergen, Martin; Meckenstock, Rainer U

2014-06-01

357

Flavor of cold-hardy grapes: impact of berry maturity and environmental conditions.  

PubMed

Since the arrival on the market of high-quality cold-hardy grape varieties, northern winemaking has been developing tremendously in countries traditionally unsuited for grape and wine production. Cold-hardy grapes are mainly interspecific hybrids of Vitis vinifera with Vitis labrusca and Vitis riparia , making their chemical composition distinct from that of V. vinifera varieties traditionally used for winemaking and therefore limiting the use of current knowledge about V. vinifera varieties in the assessment of grape maturity. Consequently, to evaluate the flavor development of cold-hardy grapes in the province of Quebec, Canada, the ripening of Frontenac and Marquette berries in two vineyards located in the southwest (SW) and northeast (NE) areas of the province, starting at the beginning of veraison, was studied. Quality attributes, phenolic compounds, and aroma profiles showed significant changes during maturation. Although full maturity was reached for both Frontenac and Marquette in the SW vineyard (1380 accumulated growing degree days, based on 10 °C), the accumulation of 1035 growing degree days was not sufficient to fully ripen Frontenac and Marquette in the NE vineyard. Principal component analysis showed different ripening patterns for the two studied locations. The longer veraison in the SW vineyard resulted in higher quality attributes and higher flavor development for both Frontenac and Marquette. Under the colder conditions in the NE vineyard, metabolite accumulation was driven primarily by berry growth, and flavor development was limited. Besides growing degree days and technological parameters (total soluble solids, pH, titratable acidity), which provide significant guidelines for maturity assessment in cold climate, phenolic maturity may be followed by the accumulation of hydroxycinnamic esters and flavonoids, although the impact of these compound classes on quality remains to be determined in cold-climate wines. In both Frontenac and Marquette, aromatic maturity was best assessed using the ratio of cis-3-hexenol to trans-2-hexenal, which showed a constant decrease until maturity. Interestingly, a shift in C6 compound profile, illustrated by the progression of the sum of C6 compounds respectively produced from linoleic (C18:2; hexanal and 1-hexanol) and ?-linolenic (C18:3; trans-2-hexenol and cis-3-hexenol) acids occurred during ripening, with ?-linolenic acid (C18:3) degradation products decreasing in both varieties as maturation approached. At harvest, aroma profiles of both Frontenac and Marquette were dominated by C6 compounds (hexanal, trans-2-hexenal, 1-hexanol, cis-3-hexenol, and hexanoic acid), acetic acid, ?-damascenone, and 2-phenylethanol, with Marquette additionally showing significant levels of monoterpenes (linalool, geraniol, and ?-citral) and 1-octen-3-ol. PMID:24151907

Pedneault, Karine; Dorais, Martine; Angers, Paul

2013-11-01

358

Characterization of environmental conditions for microbial dolomite precipitation and early diagenesis: Brejo do Espinho, Rio de Janeiro, Brazil  

NASA Astrophysics Data System (ADS)

For more than 150 years, the mineral dolomite constituting sedimentary dolomite rocks has been considered to be mainly a replacement product of the calcium carbonate components comprising the original limestone, a process known as secondary replacement dolomitization. This interpretation has been based principally on petrographic observations, as well as the analysis of the sequence of mineralogic events that have occurred during early and late diagenesis with burial. Although numerous dolomite formations in the geologic record are composed of fine-grained crystals of micritic dolomite, an alternative process, primary precipitation, is often excluded because of the absence of visible or geochemical indicators that can be used to identify this process. Defining criteria to distinguish between these two dolomite-forming processes has been hindered by the rarity of modern dolomite forming milieus where the environmental variables promoting the growth of the mineral can be studied. Here, we present a study of Brejo do Espinho, a small coastal lagoon in Rio de Janeiro State, Brazil, located in a special climate regime where a well-defined seasonal cycle of wet and dry conditions occurs. Modern dolomite precipitation from the lagoonal waters under low-temperature hypersaline conditions is deemed to be associated with the activity of microbial organisms living in this restricted environment. To advance our understanding of the biomineralization process, we characterized the variations of the physico-chemical conditions in this environment and integrated these new data with the inventory of hydrologic isotopic studies from this unique coastal region. It was possible to distinguish the environmental conditions under which two remarkable dolomite facies, fine-grained mud and semi-lithified crust, formed. The crust displays the more positive ?18O value, which is interpreted as reflecting a period when the lagoon is nearly or completely desiccated and the oxygen-18 content of the saline water is highly enriched. The mineralogical studies of the crust show that the dolomite peloids are surrounded by dolomitic microspar cement, which is characteristic of exposure episodes. These observations support the hypothesis that the crust formed under more extreme arid conditions than the mud, which precipitates in equilibrium with less oxygen-18 enriched lagoon water. However, both mud and crust formed at relatively warm Earth surface temperatures, greater than 30oC, based on clumped isotope analysis. Because similar dolomite-forming environments may have been more widespread in ancient marine or lacustrine ecosystems, the well-controlled data set acquired during this study has important implications for calibrating the environmental conditions promoting primary dolomite precipitation and early diagenesis. Calibration of the annual water cycle in modern dolomite-forming environments provides important data to develop geochemical and macro/microscopic criteria to discern the origin of ancient dolomite and possibly distinguish between the two competing mechanisms for dolomite formation.

McKenzie, J. A.; Bahniuk, A. M.; Anjos, S. C.; Perri, E.; Vasconcelos, C.

2013-12-01

359

Higher Environmental Relative Moldiness Index Values Measured in Homes of Adults with Asthma, Rhinitis, or both Conditions  

PubMed Central

Higher values of the Environmental Relative Moldiness Index (ERMI), a DNA-based method for quantifying indoor molds, have been associated with asthma in children. In this study, settled dust samples were collected from the homes of adults with asthma, rhinitis, or both conditions (n=139 homes) in Northern California. The ERMI values for these samples were compared to those from dust collected in homes from the same geographic region randomly selected as part of the 2006 American Healthy Home Survey (n=44). The median ERMI value in homes of adult with airway disease (6) was significantly greater than median ERMI value (2) in the randomly selected homes (p<0.0001). In this study in northern California, the homes of adults with asthma had ERMI values consistent with a heavier burden of indoor mold than that measured in other homes from the same region. PMID:23419817

Blanc, Paul D.; Quinlan, Patricia J.; Katz, Patricia P.; Balmes, John R.; Trupin, Laura; Cisternas, Miriam G.; Wymer, Larry; Vesper, Stephen J.

2013-01-01

360

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

2012-09-01

361

Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony (Equus ferus caballus).  

PubMed

Recent results suggest that the wild ancestor of the horse, the Przewalski horse, exhibits signs of a hypometabolism. However, there are speculations that domestic animals lost the ability to reduce energy expenditure during food shortage and adverse environmental conditions. Therefore, we investigated physiological and behavioural strategies employed by a robust domesticated horse breed, the Shetland pony, over the course of a year under temperate conditions by measuring ambient temperature (T(a)), subcutaneous temperature (T(s)), locomotor activity (LA), lying time, resting heart rate, body mass and body condition score. Ten animals were kept on pasture in summer and in open stables in winter; further, in winter the animals were allocated into one control and one feed-restricted group of five animals each to simulate natural seasonal food shortage. The annual course of the mean daily T(s) of all horses showed distinct fluctuations from a mean of 35.6±0.5°C, with higher variations in summer than in winter. Diurnal amplitudes in T(s) were highest (P<0.001) in April (12.6°C) and lowest in January (4.0°C), with a nadir around dawn and a peak around mid-day. The feed-restricted group had a significantly lower daily T(s) compared with the control group on cold winter days, with T(a) values below 0°C. Mean annual heart rate and LA followed T(a) closely. Heart rate of the feed-restricted animals significantly decreased from a mean of 52.8±8.1 beats min(-1) in summer to 29±3.9 beats min(-1) in winter and differed from the control group (P<0.001). Mean daily LA was lowest at the end of winter (7000 activity impulses day(-1)) and highest in summer (25,000 activity impulses day(-1)). Our results show that Shetland ponies exhibit signs of a winter hypometabolism indicated by reduced heart rate and T(s). Thus, domesticated horses seem to have maintained the capacity for seasonal adaptation to environmental conditions by seasonal fluctuations in their metabolic rate. PMID:22399650

Brinkmann, Lea; Gerken, Martina; Riek, Alexander

2012-04-01

362

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. PMID:21687715

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

2011-01-01

363

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. PMID:20856882

Hauri, Claudine; Fabricius, Katharina E.; Schaffelke, Britta; Humphrey, Craig

2010-01-01

364

Chemical and physical environmental conditions underneath mat- and canopy-forming macroalgae, and their effects on understorey corals.  

PubMed

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. PMID:20856882

Hauri, Claudine; Fabricius, Katharina E; Schaffelke, Britta; Humphrey, Craig

2010-01-01

365

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.  PMID:24143258

Harrison, Xavier A.; Hodgson, David J.; Inger, Richard; Colhoun, Kendrew; Gudmundsson, Gudmundur A.; McElwaine, Graham; Tregenza, Tom; Bearhop, Stuart

2013-01-01

366

Exploring chemical variables in Ligustrum lucidum Ait. F. tricolor (rehd.) Rehd. in relation to air pollutants and environmental conditions  

SciTech Connect

A diagnostic study was done on Ligustrum lucidum Ait. f. tricolor (Rehd.) Rehd. in relation to atmospheric pollutants in Cordoba city, Argentina. The study area receives regional Pollutants and was categorized taking into account traffic level, industrial density, type of industry, location of the sample point in relation to the street corner, treeless condition, and topographic level. Dried weight/fresh weight ratio (DW/FW) and specific leaf area (SLA) were calculated, and concentrations of chlorophylls, carotenoids, total sulfur, soluble proteins, malondialdehyde (MDA), and hydroperoxy conjugated dienes (HPCD) were determined in leaf samples. Sulfur content correlates positively with traffic density and SLA correlates negatively with some combinations of the categorical variables; MDA correlates positively with topographic level and total protein concentration correlates negatively with treeless condition. On the basis of our results, traffic, location of trees, type of industry, situation of a tree with respect to others, and topographic level are the environmental variables to bear in mind when selecting analogous sampling points in a passive monitoring program. An approximation to predict tree injury may be obtained by measuring DW/FW ratio, proteins, pigments, HPCD, and MDA as they are responsible for the major variability of data.

Pignata, M.L.; Canas, M.S.; Carreras, H.A. [Universidad Nacional de Cordoba (Argentina)] [Universidad Nacional de Cordoba (Argentina); Orellana, L. [Universidad de Buenos Aires (Argentina)] [Universidad de Buenos Aires (Argentina)

1997-09-01

367

Cork stoppers as an effective sorbent for water treatment: the removal of mercury at environmentally relevant concentrations and conditions.  

PubMed

The technical feasibility of using stopper-derived cork as an effective biosorbent towards bivalent mercury at environmentally relevant concentrations and conditions was evaluated in this study. Only 25 mg/L of cork powder was able to achieve 94 % of mercury removal for an initial mercury concentration of 500 ?g/L. It was found that under the conditions tested, the efficiency of mercury removal expressed as equilibrium removal percentage does not depend on the amount of cork or its particle size, but is very sensitive to initial metal concentration, with higher removal efficiencies at higher initial concentrations. Ion exchange was identified as one of the mechanisms involved in the sorption of Hg onto cork in the absence of ionic competition. Under ionic competition, stopper-derived cork showed to be extremely effective and selective for mercury in binary mixtures, while in complex matrices like seawater, moderate inhibition of the sorption process was observed, attributed to a change in mercury speciation. The loadings achieved are similar to the majority of literature values found for other biosorbents and for other metals, suggesting that cork stoppers can be recycled as an effective biosorbent for water treatment. However, the most interesting result is that equilibrium data show a very rare behaviour, with the isotherm presenting an almost square convex shape to the concentration axis, with an infinite slope for an Hg concentration in solution around 25 ?g/L. PMID:24026204

Lopes, Cláudia B; Oliveira, Joana R; Rocha, Luciana S; Tavares, Daniela S; Silva, Carlos M; Silva, Susana P; Hartog, Niels; Duarte, Armando C; Pereira, E

2014-02-01

368

Long-term effects of warming and ocean acidification are modified by seasonal variation in species responses and environmental conditions  

PubMed Central

Warming of sea surface temperatures and alteration of ocean chemistry associated with anthropogenic increases in atmospheric carbon dioxide will have profound consequences for a broad range of species, but the potential for seasonal variation to modify species and ecosystem responses to these stressors has received little attention. Here, using the longest experiment to date (542 days), we investigate how the interactive effects of warming and ocean acidification affect the growth, behaviour and associated levels of ecosystem functioning (nutrient release) for a functionally important non-calcifying intertidal polychaete (Alitta virens) under seasonally changing conditions. We find that the effects of warming, ocean acidification and their interactions are not detectable in the short term, but manifest over time through changes in growth, bioturbation and bioirrigation behaviour that, in turn, affect nutrient generation. These changes are intimately linked to species responses to seasonal variations in environmental conditions (temperature and photoperiod) that, depending upon timing, can either exacerbate or buffer the long-term directional effects of climatic forcing. Taken together, our observations caution against over emphasizing the conclusions from short-term experiments and highlight the necessity to consider the temporal expression of complex system dynamics established over appropriate timescales when forecasting the likely ecological consequences of climatic forcing. PMID:23980249

Godbold, Jasmin A.; Solan, Martin

2013-01-01

369

Lilium spp. pollen in China (Liliaceae): Taxonomic and Phylogenetic Implications and Pollen Evolution Related to Environmental Conditions  

PubMed Central

Recent molecular and karyologic studies have significantly modified delimitation of Lilium. However, despite the importance of pollen evolution in the genus comprehensive studies with electron microscopy and evaluation of pollen evolution are lacking. Therefore, we studied pollen morphology in a sample of 65 individuals from 37 taxa covering all the sections distributed in the world, using scanning electron microscopy. Our collection of 49 individuals from 21 taxa covering all five sections in China was also included in the database. We found pollen tetrads in L. bakerianum. Based on present and previous studies, our results suggest that pollen from L. formosanum should be classified as a new type, Formosanum. Combined with morphological and molecular evidence, pollen sculpture patterns appear to reflect phylogenetic relationships and are useful for species or subsection delimitation. Based on a comprehensive survey and correlation with potential functional implications, we propose the following hypothesis: evolution of an exine sculpture shows pollen type trends from Martagon ? Callose ? Concolor ? Formosanum. The evolutionary trend regarding pollen sculpture and size could be related to selective pressure to adapt to environmental conditions. Pollen size and shape showed a significantly positive correlation with annual precipitation, and smaller pollen grains appear to adapt better in habitats with extreme conditions. Evolution trends in exine sculpture do not appear to be definitively correlated with pollen size and shape. PMID:24498208

Du, Yun-peng; Wei, Chi; Wang, Zhong-xuan; Li, Shuang; He, Heng-bin; Jia, Gui-xia

2014-01-01

370

Stable isotope signatures and element stoichiometry of Fucus vesiculosus as indicators for environmental conditions in the Kiel Bight, Baltic Sea  

NASA Astrophysics Data System (ADS)

In the frame of the BMBF project BIOACID II we aim for an understanding of the natural distribution and variation of isotopic composition and C-N-S stoichiometry in Fucus vesiculosus growing around the coast line of the Kiel fjord (part of the Kiel bight). Environmental conditions (aquatic chemistry, temperature, salinity) were monitored, too. Some changes in aquatic chemistry are related to stress factors like human activity (e.g., waste input) and further factors leading to specific changes in the composition of Fucus vesiculosus. Sampling was carried out at different stations at the west and east coast of the Kiel Fjord. For each sampling station the aquatic chemistry (TA, pH, salinity, d13C(DIC), main and trace elements and nutrients) as well as the composition of the Fucus organic tissues (stoichiometry and stable isotope composition of carbon, nitrogen) are analysed. The Fucus tissue was sampled in three size classes (small, medium, large). It is shown, that Fucus vesiculosus indicates clear differences in the N contents and stable isotopes between the west and the east site of the Kiel Fjord. Stable nitrogen isotope signatures in Fucus vesiculosus, are useful proxies to identify the influence factors in the Fucus habitat. From the data it is obtained that the influence of human activity (wastewater treatment plant, harbour), small stream and drainage channels, which flow from the near coastal area into the bight, leads to different Fucus vesiculosus compositions. In future work, it is intended to extend the investigation to trace element signatures to further estimate environmental impacts.

Winde, Vera; Mahler, Annika; Voss, Maren; Böttcher, Michael E.

2014-05-01

371

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

372

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

373

Surface adsorption, intracellular accumulation and compartmentalization of Pb(II) in batch-operated lagoons with Salvinia minima as affected by environmental conditions, EDTA and nutrients  

Microsoft Academic Search

The effects of environmental factors and nutrients on the various possible removal mechanisms (surface adsorption, intracellular\\u000a accumulation and precipitation to sediments) and partitioning of lead among various compartments (plant biomass, water column\\u000a and sediments) in Salvinia minima batch-operated lagoons, were evaluated. Surface adsorption was found to be the predominant mechanism for Pb(II) removal under\\u000a all environmental conditions tested in the

Eugenia J. Olguín; Gloria Sánchez-Galván; Teresa Pérez-Pérez; Arith Pérez-Orozco

2005-01-01

374

Effects of Varying Environmental Conditions on Biological Control of Fusarium Wilt of Tomato by Nonpathogenic Fusarium spp.  

PubMed

ABSTRACT The influence of varying environmental and cropping conditions including temperature, light, soil type, pathogen isolate and race, and cultivar of tomato on biological control of Fusarium wilt of tomato by isolates of nonpathogenic Fusarium oxysporum (CS-20 and CS-24) and F. solani (CS-1) was evaluated in greenhouse and growth chamber experiments. Liquid spore suspensions (10(6)/ml) of the biocontrol isolates were applied to soilless potting mix at the time of tomato seeding, and the seedlings were transplanted into pathogen-infested field soil 2 weeks later. Temperature regimes ranging from 22 to 32 degrees C significantly affected disease development and plant physiological parameters. Biocontrol isolate CS-20 significantly reduced disease at all temperature regimes tested, yielding reductions of disease incidence of 59 to 100% relative to pathogen control treatments. Isolates CS-24 and CS-1 reduced disease incidence in the greenhouse and at high temperatures, but were less effective at the optimum temperature for disease development (27 degrees C). Growing plants under shade (50% of full light) versus full light affected some plant growth parameters, but did not affect the efficacy of biocontrol of any of the three bio-control isolates. Isolate CS-20 effectively reduced disease incidence (56 to 79% reduction) in four different field soils varying in texture (sandy to clayey) and organic matter content (0 to 3.2%). Isolate CS-1 reduced disease in the sandy and loamy soils (49 to 66% reduction), but was not effective in a heavy clay soil. Both CS-1 and CS-20 were equally effective against all three races of the pathogen, as well as multiple isolates of each race (48 to 66% reduction in disease incidence). Both isolates, CS-1 and CS-20, were equally effective in reducing disease incidence (66 to 80% reduction) by pathogenic races 1, 2, and 3 on eight different tomato cultivars containing varying levels of inherent resistance to Fusarium wilt (susceptible, resistant to race 1, or resistant to races 1 and 2). These results demonstrate that both these Fusarium isolates, and particularly CS-20, can effectively reduce Fusarium wilt disease of tomato under a variety of environmental conditions and have potential for further development. PMID:18944240

Larkin, Robert P; Fravel, Deborah R

2002-11-01

375

Characterization of a novel carbonic anhydrase from freshwater pearl mussel Hyriopsis cumingii and the expression profile of its transcript in response to environmental conditions.  

PubMed

Gene encoding for ?-carbonic anhydrases (?-CAs) and their functions in fundamental metabolism and biomineralization are widely identified in mollusks. However, the transcriptional regulation of ?-CA genes in response to various environmental conditions remains unknown. In the present study, we characterized a cDNA encoding for an ?-CA (HcCA) from the freshwater pearl mussel Hyriopsis cumingii. The spatial and temporal expression patterns of HcCA indicate that this gene is mainly expressed in the mantle of juvenile mussels. The expression profile of HcCA under various environmental conditions reveals that the transcription of HcCA is significantly regulated by Ca(2+) concentration, water temperature, pH and air exposure. Our results suggest that HcCA is a crucial target gene by which the external environmental conditions affecting shell growth and pH homeostasis of H. cumingii. PMID:24853200

Ren, Gang; Wang, Yan; Qin, Jianguang; Tang, Jinyu; Zheng, Xiafei; Li, Youming

2014-08-01

376

Mid-Holocene inundation of the Lower Danube Valley - Lake sediments reflecting changing environmental conditions and human impact  

NASA Astrophysics Data System (ADS)

Geoarchaeological research has been conducted in the valley of the Lower Danube between Giurgiu and Oltenita to reconstruct changing environmental conditions and human impact during the Holocene with special focus on the Copper Age (5th millennium BC). Numerous settlement mounds indicate that settlements existed along the Lower Danube during this period, one of the most important being the tell of Pietrele in the study area. Our palaeoecological research concentrates on floodplain sediments covering the valley bottom, which is about 8 km wide. More than 160 sediment cores were taken and complemented by geoelectric measurements. A multi-proxy approach consisting of sedimentological and geochemical analyses as well as analysis of microfauna (ostracodes), pollen and macro remains has been applied. The chronological frame is based on AMS-14C and OSL-dating. The results indicate that after the deposition of sands and gravels by a braided river system, lake sediments accumulated covering nearly the whole valley bottom. While the sands were dated to LGM and Late Glacial the deposition of lake sediments occurred from mid to late Holocene. The inundation of the Lower Danube valley was possibly caused by the transgression of the Black Sea. Within the lake sediments several black layers, each with a characteristic geochemical composition, appear. Those marker layers indicate changing conditions or events during lake evolution. The lowermost dark layer can be attributed to the Copper Age settlement period. It can be presumed that the development of the distinctive layer was caused by an increase of eroded soil material and/or of nutrients originating from settlements and agriculture that were washed into the lake. The upper part of the sediment record indicates that branches of the Danube prograded into the lake, starting not earlier than 2000 years ago. An anabranching river system established. Only remnants of the vast palaeolake prevailed until they were drained in the 1960ies.

Nowacki, Dirk; Wunderlich, Jürgen

2013-04-01

377

Timing, Frequency and Environmental Conditions Associated with Mainstem–Tributary Movement by a Lowland River Fish, Golden Perch (Macquaria ambigua)  

PubMed Central

Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007–2011). Fish were tagged and released in autumn 2007–2009 in the mid-Murray (n?=?42) and lower Goulburn (n?=?37) rivers within 3–6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem–tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem–tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers. PMID:24788137

Koster, Wayne M.; Dawson, David R.; O’Mahony, Damien J.; Moloney, Paul D.; Crook, David A.

2014-01-01

378

Effects of Cd & Ni toxicity to Ceratophyllum demersum under environmentally relevant conditions in soft & hard water including a German lake.  

PubMed

Even essential trace elements are phytotoxic over a certain threshold. In this study, we investigated whether heavy metal concentrations were responsible for the nearly complete lack of submerged macrophytes in an oligotrophic lake in Germany. We cultivated the rootless aquatic model plant Ceratophyllum demersum under environmentally relevant conditions like sinusoidal light and temperature cycles and a low plant biomass to water volume ratio. Experiments lasted for six weeks and were analysed by detailed measurements of photosynthetic biophysics, pigment content and hydrogen peroxide production. We established that individually non-toxic cadmium (3 nM) and slightly toxic nickel (300 nM) concentrations became highly toxic when applied together in soft water, severely inhibiting photosynthetic light reactions. Toxicity was further enhanced by phosphate limitation (75 nM) in soft water as present in many freshwater habitats. In the investigated lake, however, high water hardness limited the toxicity of these metal concentrations, thus the inhibition of macrophytic growth in the lake must have additional reasons. The results showed that synergistic heavy metal toxicity may change ecosystems in many more cases than estimated so far. PMID:24096235

Andresen, Elisa; Opitz, Judith; Thomas, George; Stärk, Hans-Joachim; Dienemann, Holger; Jenemann, Kerstin; Dickinson, Bryan C; Küpper, Hendrik

2013-10-15

379

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. PMID:22081581

Al-Tebrineh, Jamal; Merrick, Chester; Ryan, David; Humpage, Andrew; Bowling, Lee

2012-01-01

380

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

2012-09-01

381

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

2012-01-01

382

Enhanced cytokine-induced mechanical hyperalgesia in skeletal muscle produced by a novel mechanism in rats exposed to unpredictable sound stress  

PubMed Central

Stress exacerbates both experimental and clinical pain, most well-characterized in irritable bowel and fibromyalgia syndromes. Since it has been hypothesized that cytokines play an etiopathogenic role in fibromyalgia and other chronic widespread pain conditions, we investigated the relationship between stress and cytokines in a model of stress-induced chronic somatic pain. A series of experiments were performed to evaluate the impact of stress on the hyperalgesia-induced by endotoxin (lipopolysaccharide, LPS) and the role of two proinflammatory cytokines, interleukin-6 (IL-6) and tumor necrosis ? (TNF?). Fourteen days after exposure to a 4-day protocol of unpredictable sound stress, the ability of systemic LPS (100 ?g/kg, i.p) to elicit cytokine-mediated mechanical hyperalgesia was measured in gastrocnemius muscle. LPS-induced hyperalgesia was significantly greater in stressed rats, but when rats were treated intrathecally with antisense oligodeoxynucleotide (ODN), to decrease either the gp130 subunit of the IL-6 receptor or the TNF? receptor, in nociceptors, skeletal muscle hyperalgesia in sound stressed, but not control, rats was prevented. These data suggest that chronic stress alters signaling in the primary afferent nociceptor for the hyperalgesia induced by endogenously produced pro-inflammatory cytokines. PMID:21419675

Dina, Olayinka A.; Levine, Jon D.; Green, Paul G.

2011-01-01

383

Epigallocatechin-3-Gallate Attenuates Impairment of Learning and Memory in Chronic Unpredictable Mild Stress-Treated Rats by Restoring Hippocampal Autophagic Flux  

PubMed Central

Epigallocatechin gallate (EGCG) is a major polyphenol in green tea with beneficial effects on the impairment in learning and memory. Autophagy is a cellular process that protects neurons from stressful conditions. The present study was designed to investigate whether EGCG can rescue chronic unpredictable mild stress (CUMS)-induced cognitive impairment in rats and whether its protective effect involves improvement of autophagic flux. As expected, our results showed that CUMS significantly impaired memory performance and inhibited autophagic flux as indicated by elevated LC3-II and p62 protein levels. At the same time, we observed an increased neuronal loss and activated mammalian target of rapamycin (mTOR)/p70 ribosomal protein S6 kinase (p70S6k) signaling in the CA1 regions. Interestingly, chronic treatment with EGCG (25 mg/kg, i.p.) significantly improved those behavioral alterations, attenuated histopathological abnormalities in hippocampal CA1 regions, reduced amyloid beta1–42 (A?1?42) levels, and restored autophagic flux. However, blocking autophagic flux with chloroquine, an inhibitor of autophagic flux, reversed these effects of EGCG. Taken together, these findings suggest that the impaired autophagy in CA1 regions of CUMS rats may contribute to learning and memory impairment. Therefore, we conclude that EGCG attenuation of CUMS-induced learning and memory impairment may be through rescuing autophagic flux. PMID:25393306

Tang, Ya-Ling; Zeng, Yang; Jing, Kai-Quan; Zheng, Xi-Long; Liao, Duan-Fang

2014-01-01

384

Experimental Demonstration of the Formation of Liquid Brines under Martian Polar Conditions in the Michigan Mars Environmental Chamber  

NASA Astrophysics Data System (ADS)

Liquid water is one of the necessary ingredients for the development of life as we know it. The behavior of various liquid states of H2O such as liquid brine, undercooled liquid interfacial water, subsurface melt water and ground water [1] needs to be understood in order to address the potential habitability of Mars for microbes and future human exploration. It has been shown thermodynamically that liquid brines can exist under Martian polar conditions [2, 3]. We have developed the Michigan Mars Environmental Chamber (MMEC) to simulate the entire range of Martian surface and shallow subsurface conditions with respect to temperature, pressure, relative humidity, solar radiation and soil wetness at equatorial and polar latitudes. Our experiments in the MMEC show that deliquescence of NaClO4, Mg(ClO4)2 and Ca(ClO4)2 occurs diurnally under the environmental conditions of the Phoenix landing site when these salts get in contact with water ice. Since Phoenix detected these salts and water ice at the landing site, including frost formation, it is extremely likely that deliquescence occurs at the Phoenix landing site. By layering NaClO4, Mg(ClO4)2 or Ca(ClO4)2 on top of a pure water ice slab at 800 Pa and 190 K and raising the temperature stepwise across the eutectic temperature of the perchlorate salts, we observe distinct changes in the Raman spectra of the samples when deliquescence occurs. When crossing the eutectic temperatures of NaClO4 (236 K), Mg(ClO4)2 (205 K) and Ca(ClO4)2 (199 K) [4, 5], the perchlorate band of the Raman spectrum shows a clear shift from 953 cm-1 to 936 cm-1. Furthermore, the appearance of a broad O-H vibrational stretching spectrum between 3244 cm-1 and 3580 cm-1 is another indicator of deliquescence. This process of deliquescence occurs on the order of seconds when the perchlorate salt is in contact with water ice. On the contrary, when the perchlorate salt is only subjected to water vapor in the Martian atmosphere, deliquescence was not observed within the Martian diurnal cycle. Th