Varying constants, black holes, and quantum gravity

International Nuclear Information System (INIS)

Carlip, S.

2003-01-01

Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain 'constants' vary in time. Assuming fixed black hole mass and the standard form of the Bekenstein-Hawking entropy, Davies, Davis and Lineweaver have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that with these assumptions, similar considerations severely constrain 'varying speed of light' models, unless we are prepared to abandon cherished assumptions about quantum gravity. Relaxation of these assumptions permits sensible theories of quantum gravity with ''varying constants,'' but also eliminates the thermodynamic constraints, though the black hole mass spectrum may still provide some restrictions on the range of allowable models

Infusing considerations of trophic dependencies into species distribution modelling.

Science.gov (United States)

Trainor, Anne M; Schmitz, Oswald J

2014-12-01

Community ecology involves studying the interdependence of species with each other and their environment to predict their geographical distribution and abundance. Modern species distribution analyses characterise species-environment dependency well, but offer only crude approximations of species interdependency. Typically, the dependency between focal species and other species is characterised using other species' point occurrences as spatial covariates to constrain the focal species' predicted range. This implicitly assumes that the strength of interdependency is homogeneous across space, which is not generally supported by analyses of species interactions. This discrepancy has an important bearing on the accuracy of inferences about habitat suitability for species. We introduce a framework that integrates principles from consumer-resource analyses, resource selection theory and species distribution modelling to enhance quantitative prediction of species geographical distributions. We show how to apply the framework using a case study of lynx and snowshoe hare interactions with each other and their environment. The analysis shows how the framework offers a spatially refined understanding of species distribution that is sensitive to nuances in biophysical attributes of the environment that determine the location and strength of species interactions. © 2014 John Wiley & Sons Ltd/CNRS.

Deficit in community species richness as explained by area and isolation of sites

DEFF Research Database (Denmark)

Bruun, Hans Henrik

2000-01-01

The potential community species richness was predicted for 85 patches of seminatural grassland in an agricultural landscape in Denmark. The basis of the prediction was a very large dataset on the vegetation, soil pH and topography in Danish grasslands and related communities. Species were inserte......, community richness deficit, varied considerably among patches. Community richness deficit exhibited a negative relationship with patch area, and for small patches a positive relationship with patch isolation....

Species Identification and Design Value Estimation of Wooden Members in Covered Bridges

Science.gov (United States)

Alex C. Wiedenhoeft; David E. Kretschmann

2014-01-01

Covered timber bridges are historic structures with unique aesthetic value. To preserve this value and maintain bridges in service, robust evaluation of their performance and safety is necessary. The strength of the timber found in covered bridges can vary considerably, not only because of age and condition, but also because of species and grade. For the practicing...

76 FR 515 - Endangered and Threatened Species, Designation of Critical Habitat for Southern Distinct...

Science.gov (United States)

2011-01-05

... populations spawning west of Cook Inlet, Alaska). In the portion of the species' range that lies south of the... Life History and Maturation Eulachon eggs can vary considerably in size but typically are approximately...). Eggs are enclosed in a double membrane; after fertilization in the water, the outer membrane breaks and...

Multivariate time-varying volatility modeling using probabilistic fuzzy systems

NARCIS (Netherlands)

Basturk, N.; Almeida, R.J.; Golan, R.; Kaymak, U.

2016-01-01

Methods to accurately analyze financial risk have drawn considerable attention in financial institutions. One difficulty in financial risk analysis is the fact that banks and other financial institutions invest in several assets which show time-varying volatilities and hence time-varying financial

Quantifying in situ phenotypic variability in the hydraulic properties of four tree species across their distribution range in Europe

NARCIS (Netherlands)

González-Muñoz, N.; Sterck, F.; Torres-Ruiz, J.M.; Petit, G.; Cochard, H.; Arx, von G.; Lintunen, A.; Caldeira, M.C.; Capdeville, G.; Copini, P.; Gebauer, R.; Grönlund, L.; Hölttä, T.; Lobo-do-Vale, R.; Peltoniemi, M.; Stritih, A.; Urban, J.; Delzon, S.

2018-01-01

Many studies have reported that hydraulic properties vary considerably between tree species, but little is known about their intraspecific variation and, therefore, their capacity to adapt to a warmer and drier climate. Here, we quantify phenotypic divergence and clinal variation for embolism

Benchmarking novel approaches for modelling species range dynamics.

Science.gov (United States)

Zurell, Damaris; Thuiller, Wilfried; Pagel, Jörn; Cabral, Juliano S; Münkemüller, Tamara; Gravel, Dominique; Dullinger, Stefan; Normand, Signe; Schiffers, Katja H; Moore, Kara A; Zimmermann, Niklaus E

2016-08-01

Increasing biodiversity loss due to climate change is one of the most vital challenges of the 21st century. To anticipate and mitigate biodiversity loss, models are needed that reliably project species' range dynamics and extinction risks. Recently, several new approaches to model range dynamics have been developed to supplement correlative species distribution models (SDMs), but applications clearly lag behind model development. Indeed, no comparative analysis has been performed to evaluate their performance. Here, we build on process-based, simulated data for benchmarking five range (dynamic) models of varying complexity including classical SDMs, SDMs coupled with simple dispersal or more complex population dynamic models (SDM hybrids), and a hierarchical Bayesian process-based dynamic range model (DRM). We specifically test the effects of demographic and community processes on model predictive performance. Under current climate, DRMs performed best, although only marginally. Under climate change, predictive performance varied considerably, with no clear winners. Yet, all range dynamic models improved predictions under climate change substantially compared to purely correlative SDMs, and the population dynamic models also predicted reasonable extinction risks for most scenarios. When benchmarking data were simulated with more complex demographic and community processes, simple SDM hybrids including only dispersal often proved most reliable. Finally, we found that structural decisions during model building can have great impact on model accuracy, but prior system knowledge on important processes can reduce these uncertainties considerably. Our results reassure the clear merit in using dynamic approaches for modelling species' response to climate change but also emphasize several needs for further model and data improvement. We propose and discuss perspectives for improving range projections through combination of multiple models and for making these approaches

Characteristics of organic acids in the fruit of different pumpkin species.

Science.gov (United States)

Nawirska-Olszańska, Agnieszka; Biesiada, Anita; Sokół-Łętowska, Anna; Kucharska, Alicja Z

2014-04-01

The aim of the research was to determine the composition of organic acids in fruit of different cultivars of three pumpkin species. The amount of acids immediately after fruit harvest and after 3 months of storage was compared. The content of organic acids in the examined pumpkin cultivars was assayed using the method of high performance liquid chromatography (HPLC). Three organic acids (citric acid, malic acid, and fumaric acid) were identified in the cultivars, whose content considerably varied depending on a cultivar. Three-month storage resulted in decreased content of the acids in the case of cultivars belonging to Cucurbita maxima and Cucurbita pepo species, while a slight increase was recorded for Cucurbita moschata species. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Plants, birds and butterflies: short-term responses of species communities to climate warming vary by taxon and with altitude.

Science.gov (United States)

Roth, Tobias; Plattner, Matthias; Amrhein, Valentin

2014-01-01

As a consequence of climate warming, species usually shift their distribution towards higher latitudes or altitudes. Yet, it is unclear how different taxonomic groups may respond to climate warming over larger altitudinal ranges. Here, we used data from the national biodiversity monitoring program of Switzerland, collected over an altitudinal range of 2500 m. Within the short period of eight years (2003-2010), we found significant shifts in communities of vascular plants, butterflies and birds. At low altitudes, communities of all species groups changed towards warm-dwelling species, corresponding to an average uphill shift of 8 m, 38 m and 42 m in plant, butterfly and bird communities, respectively. However, rates of community changes decreased with altitude in plants and butterflies, while bird communities changed towards warm-dwelling species at all altitudes. We found no decrease in community variation with respect to temperature niches of species, suggesting that climate warming has not led to more homogenous communities. The different community changes depending on altitude could not be explained by different changes of air temperatures, since during the 16 years between 1995 and 2010, summer temperatures in Switzerland rose by about 0.07°C per year at all altitudes. We discuss that land-use changes or increased disturbances may have prevented alpine plant and butterfly communities from changing towards warm-dwelling species. However, the findings are also consistent with the hypothesis that unlike birds, many alpine plant species in a warming climate could find suitable habitats within just a few metres, due to the highly varied surface of alpine landscapes. Our results may thus support the idea that for plants and butterflies and on a short temporal scale, alpine landscapes are safer places than lowlands in a warming world.

Time-varying BRDFs.

Science.gov (United States)

Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

2007-01-01

The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

Eimeria species occurrence varies between geographic regions and poultry production systems and may influence parasite genetic diversity.

Science.gov (United States)

Chengat Prakashbabu, B; Thenmozhi, V; Limon, G; Kundu, K; Kumar, S; Garg, R; Clark, E L; Srinivasa Rao, A S R; Raj, D G; Raman, M; Banerjee, P S; Tomley, F M; Guitian, J; Blake, D P

2017-01-15

Coccidiosis is one of the biggest challenges faced by the global poultry industry. Recent studies have highlighted the ubiquitous distribution of all Eimeria species which can cause this disease in chickens, but intriguingly revealed a regional divide in genetic diversity and population structure for at least one species, Eimeria tenella. The drivers associated with such distinct geographic variation are unclear, but may impact on the occurrence and extent of resistance to anticoccidial drugs and future subunit vaccines. India is one of the largest poultry producers in the world and includes a transition between E. tenella populations defined by high and low genetic diversity. The aim of this study was to identify risk factors associated with the prevalence of Eimeria species defined by high and low pathogenicity in northern and southern states of India, and seek to understand factors which vary between the regions as possible drivers for differential genetic variation. Faecal samples and data relating to farm characteristics and management were collected from 107 farms from northern India and 133 farms from southern India. Faecal samples were analysed using microscopy and PCR to identify Eimeria occurrence. Multiple correspondence analysis was applied to transform correlated putative risk factors into a smaller number of synthetic uncorrelated factors. Hierarchical cluster analysis was used to identify poultry farm typologies, revealing three distinct clusters in the studied regions. The association between clusters and presence of Eimeria species was assessed by logistic regression. The study found that large-scale broiler farms in the north were at greatest risk of harbouring any Eimeria species and a larger proportion of such farms were positive for E. necatrix, the most pathogenic species. Comparison revealed a more even distribution for E. tenella across production systems in south India, but with a lower overall occurrence. Such a polarised region- and

Transfer Factors of Nuclides for Five Fish Species Inhabiting the Sea near the Yonggwang Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Lim, Kwangmuk; Choi, Yongho; Jun, In; Kim, Byungho; Keum, Dongkwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-05-15

The IAEA is going to publish a handbook of the TF values of various radionuclides for a number of plant and animal species. However, it is recommended that they be used in case there is no site-specific data. This is because TF values can vary considerably with wild-life species and environmental conditions. Therefore, it is necessary to urgently establish our own database of wild-life transfer factors for use in the wild-life dose assessment probably in the near future. In the present study, TF values of various radionuclides were investigated for several marine fish species living around the Younggwang NPP. It was done by measuring the concentrations of stable isotopes in fish and seawater samples. TF values of 21 nuclides were measured for five fish species inhabiting the sea near the Younggwang NPP. They showed considerable variations with the nuclides and fish species. Determination of TF values needs to be extended to various kinds of domestic wild lives so as to establish an input data file for a Korean assessment model such as K-BIOTA.

Angular distribution of species in pulsed laser deposition of LaxCa1-xMnO3

Science.gov (United States)

Ojeda-G-P, Alejandro; Schneider, Christof W.; Döbeli, Max; Lippert, Thomas; Wokaun, Alexander

2015-05-01

The angular distribution of species from a La0.4Ca0.6MnO3 target irradiated with a 248 nm nanosecond pulsed laser was investigated by Rutherford backscattering spectrometry for four different Ar pressures. The film thickness angular distribution was also analyzed using profilometry. Depending on the background gas pressure, the target to substrate distance, and the angular location the film thickness and composition varies considerably. In particular the film composition could vary by up to 17% with respect to the composition of the target material.

Do non-native plant species affect the shape of productivity-diversity relationships?

Science.gov (United States)

Drake, J.M.; Cleland, E.E.; Horner-Devine, M. C.; Fleishman, E.; Bowles, C.; Smith, M.D.; Carney, K.; Emery, S.; Gramling, J.; Vandermast, D.B.; Grace, J.B.

2008-01-01

The relationship between ecosystem processes and species richness is an active area of research and speculation. Both theoretical and experimental studies have been conducted in numerous ecosystems. One finding of these studies is that the shape of the relationship between productivity and species richness varies considerably among ecosystems and at different spatial scales, though little is known about the relative importance of physical and biological mechanisms causing this variation. Moreover, despite widespread concern about changes in species' global distributions, it remains unclear if and how such large-scale changes may affect this relationship. We present a new conceptual model of how invasive species might modulate relationships between primary production and species richness. We tested this model using long-term data on relationships between aboveground net primary production and species richness in six North American terrestrial ecosystems. We show that primary production and abundance of non-native species are both significant predictors of species richness, though we fail to detect effects of invasion extent on the shapes of the relationship between species richness and primary production.

Plant Mating Systems Often Vary Widely Among Populations

Directory of Open Access Journals (Sweden)

Michael R. Whitehead

2018-04-01

Full Text Available Most flowering plants are hermaphroditic, yet the proportion of seeds fertilized by self and outcross pollen varies widely among species, ranging from predominant self-fertilization to exclusive outcrossing. A population's rate of outcrossing has important evolutionary outcomes as it influences genetic structure, effective population size, and offspring fitness. Because most mating system studies have quantified outcrossing rates for just one or two populations, past reviews of mating system diversity have not been able to characterize the extent of variation among populations. Here we present a new database of more than 30 years of mating system studies that report outcrossing rates for three or more populations per species. This survey, which includes 741 populations from 105 species, illustrates substantial and prevalent among-population variation in the mating system. Intermediate outcrossing rates (mixed mating are common; 63% of species had at least one mixed mating population. The variance among populations and within species was not significantly correlated with pollination mode or phylogeny. Our review underscores the need for studies exploring variation in the relative influence of ecological and genetic factors on the mating system, and how this varies among populations. We conclude that estimates of outcrossing rates from single populations are often highly unreliable indicators of the mating system of an entire species.

[Theological moral considerations of advance directives].

Science.gov (United States)

Virt, G

1997-01-01

The forms for advanced directives vary considerably in respect to content and wording. This article intends to develop ethical criteria for such texts, from the moraltheological point of view, also considering the social context.

Important variations in parvalbumin content in common fish species: a factor possibly contributing to variable allergenicity.

Science.gov (United States)

Kuehn, A; Scheuermann, T; Hilger, C; Hentges, F

2010-01-01

Although 95% of fish-allergic patients are sensitized to the major fish allergen parvalbumin, clinical reactions to different fish species vary considerably in symptoms, intensity and frequency in allergic subjects. This study aimed at the quantification of parvalbumin levels in salmon, trout, cod, carp, mackerel, herring, redfish and tuna. Fish muscle extracts were separated by SDS-PAGE and parvalbumin content was estimated by densitometric band quantification. Individual antisera were raised in BALB/c mice against parvalbumins purified from seven fish species. Parvalbumin content was quantified in fish (raw/processed) and skin prick test (SPT) solutions by ELISA using the corresponding anti-serum for detection and the purified parvalbumins as standards. Using SDS-PAGE scanning, parvalbumin contents were 2 mg for cod, carp, redfish and herring. Using ELISA, parvalbumin content ranged from 2.5 mg per gram raw muscle for carp, herring and redfish. The parvalbumin content of processed samples (cooked/commercial) was 20-60% lower. Allergen content in SPT samples ranged from 20 to 70 μg parvalbumin/ml of extract. No parvalbumin was found in tuna SPT solution. The parvalbumin content of most commonly consumed fish species varies considerably. Differences range from severalfold to one hundredfold. This has to be taken into account when designing food challenge tests and advising fish-allergic patients. Copyright © 2010 S. Karger AG, Basel.

Fusariotoxins in Avian Species: Toxicokinetics, Metabolism and Persistence in Tissues

Directory of Open Access Journals (Sweden)

Philippe Guerre

2015-06-01

Full Text Available Fusariotoxins are mycotoxins produced by different species of the genus Fusarium whose occurrence and toxicity vary considerably. Despite the fact avian species are highly exposed to fusariotoxins, the avian species are considered as resistant to their toxic effects, partly because of low absorption and rapid elimination, thereby reducing the risk of persistence of residues in tissues destined for human consumption. This review focuses on the main fusariotoxins deoxynivalenol, T-2 and HT-2 toxins, zearalenone and fumonisin B1 and B2. The key parameters used in the toxicokinetic studies are presented along with the factors responsible for their variations. Then, each toxin is analyzed separately. Results of studies conducted with radiolabelled toxins are compared with the more recent data obtained with HPLC/MS-MS detection. The metabolic pathways of deoxynivalenol, T-2 toxin, and zearalenone are described, with attention paid to the differences among the avian species. Although no metabolite of fumonisins has been reported in avian species, some differences in toxicokinetics have been observed. All the data reviewed suggest that the toxicokinetics of fusariotoxins in avian species differs from those in mammals, and that variations among the avian species themselves should be assessed.

Consideration of species differences in developing novel molecules as cognition enhancers.

Science.gov (United States)

Young, Jared W; Jentsch, J David; Bussey, Timothy J; Wallace, Tanya L; Hutcheson, Daniel M

2013-11-01

The NIH-funded CNTRICS initiative has coordinated efforts to promote the vertical translation of novel procognitive molecules from testing in mice, rats and non-human primates, to clinical efficacy in patients with schizophrenia. CNTRICS highlighted improving construct validation of tasks across species to increase the likelihood that the translation of a candidate molecule to humans will be successful. Other aspects of cross-species behaviors remain important however. This review describes cognitive tasks utilized across species, providing examples of differences and similarities of innate behavior between species, as well as convergent construct and predictive validity. Tests of attention, olfactory discrimination, reversal learning, and paired associate learning are discussed. Moreover, information on the practical implication of species differences in drug development research is also provided. The issues covered here will aid in task development and utilization across species as well as reinforcing the positive role preclinical research can have in developing procognitive treatments for psychiatric disorders. Copyright © 2012 Elsevier Ltd. All rights reserved.

Time-varying value of electric energy efficiency

Energy Technology Data Exchange (ETDEWEB)

Mims, Natalie A.; Eckman, Tom; Goldman, Charles

2017-06-30

Electric energy efficiency resources save energy and may reduce peak demand. Historically, quantification of energy efficiency benefits has largely focused on the economic value of energy savings during the first year and lifetime of the installed measures. Due in part to the lack of publicly available research on end-use load shapes (i.e., the hourly or seasonal timing of electricity savings) and energy savings shapes, consideration of the impact of energy efficiency on peak demand reduction (i.e., capacity savings) has been more limited. End-use load research and the hourly valuation of efficiency savings are used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity and demand response planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service. This study reviews existing literature on the time-varying value of energy efficiency savings, provides examples in four geographically diverse locations of how consideration of the time-varying value of efficiency savings impacts the calculation of power system benefits, and identifies future research needs to enhance the consideration of the time-varying value of energy efficiency in cost-effectiveness screening analysis. Findings from this study include: -The time-varying value of individual energy efficiency measures varies across the locations studied because of the physical and operational characteristics of the individual utility system (e.g., summer or winter peaking, load factor, reserve margin) as well as the time periods during which savings from measures occur. -Across the four locations studied, some of the largest capacity benefits from energy efficiency are derived from the deferral of transmission and distribution system infrastructure upgrades. However, the deferred cost of such upgrades also exhibited the greatest range

Zonadhesin D3-Polypeptides Vary among Species but Are Similar in Equus Species Capable of Interbreeding1

OpenAIRE

Tardif, Steve; Brady, Heidi A.; Breazeale, Kelly R.; Bi, Ming; Thompson, Leslie D.; Bruemmer, Jason E.; Bailey, Laura B.; Hardy, Daniel M.

2009-01-01

Zonadhesin is a rapidly evolving protein in the sperm acrosome that confers species specificity to sperm-zona pellucida adhesion. Though structural variation in zonadhesin likely contributes to its species-specific function, the protein has not previously been characterized in organisms capable of interbreeding. Here we compared properties of zonadhesin in several animals, including the horse (Equus caballus), donkey (E. asinus), and Grevy's zebra (E. grevyi) to determine if variation in zona...

Symbiotic effectiveness of rhizobial mutualists varies in interactions with native Australian legume genera.

Directory of Open Access Journals (Sweden)

Peter H Thrall

Full Text Available BACKGROUND AND OBJECTIVES: Interactions between plants and beneficial soil organisms (e.g. rhizobial bacteria, mycorrhizal fungi are models for investigating the ecological impacts of such associations in plant communities, and the evolution and maintenance of variation in mutualisms (e.g. host specificity and the level of benefits provided. With relatively few exceptions, variation in symbiotic effectiveness across wild host species is largely unexplored. METHODS: We evaluated these associations using representatives of several legume genera which commonly co-occur in natural ecosystems in south-eastern Australia and an extensive set of rhizobial strains isolated from these hosts. These strains had been previously assigned to specific phylotypes on the basis of molecular analyses. In the first of two inoculation experiments, the growth responses of each host species was evaluated with rhizobial strains isolated from that species. The second experiment assessed performance across genera and the extent of host specificity using a subset of these strains. RESULTS: While host growth responses to their own (sympatric isolates varied considerably, rhizobial phylotype was a significant predictor of symbiotic performance, indicating that bacterial species designations on the basis of molecular markers have ecological importance. Hosts responded in qualitatively different ways to sympatric and allopatric strains of rhizobia, ranging from species with a clear preference for their own strains, to those that were broad generalists, through to species that grew significantly better with allopatric strains. CONCLUSION: Theory has focused on trade-offs between the provision of benefits and symbiont competitive ability that might explain the persistence of less beneficial strains. However, differences in performance among co-occurring host species could also drive such patterns. Our results thus highlight the likely importance of plant community structure in

Effect of intra- and interspecific competition on the performance of native and invasive species of Impatiens under varying levels of shade and moisture.

Science.gov (United States)

Skálová, Hana; Jarošík, Vojtěch; Dvořáčková, Śárka; Pyšek, Petr

2013-01-01

Many alien plants are thought to be invasive because of unique traits and greater phenotypic plasticity relative to resident species. However, many studies of invasive species are unable to quantify the importance of particular traits and phenotypic plasticity in conferring invasive behavior because traits used in comparative studies are often measured in a single environment and by using plants from a single population. To obtain a deeper insight into the role of environmental factors, local differences and competition in plant invasions, we compared species of Impatiens (Balsaminaceae) of different origin and invasion status that occur in central Europe: native I. noli-tangere and three alien species (highly invasive I. glandulifera, less invasive I. parviflora and potentially invasive I. capensis). In two experiments we harvested late-stage reproductive plants to estimate performance. The first experiment quantified how populations differed in performance under varying light and moisture levels in the absence of competition. The second experiment quantified performance across these environments in the presence of intra- and inter-specific competition. The highly invasive I. glandulifera was the strongest competitor, was the tallest and produced the greatest biomass. Small size and high plasticity were characteristic for I. parviflora. This species appeared to be the second strongest competitor, especially under low soil moisture. The performance of I. capensis was within the range of the other Impatiens species studied, but sometimes limited by alien competitors. Our results suggest that invasion success within the genus Impatiens depends on the ability to grow large under a range of environmental conditions, including competition. The invasive species also exhibited greater phenotypic plasticity across environmental conditions than the native species. Finally, the decreased performance of the native I. noli-tangere in competition with other species studied

Effect of intra- and interspecific competition on the performance of native and invasive species of Impatiens under varying levels of shade and moisture.

Directory of Open Access Journals (Sweden)

Hana Skálová

Full Text Available Many alien plants are thought to be invasive because of unique traits and greater phenotypic plasticity relative to resident species. However, many studies of invasive species are unable to quantify the importance of particular traits and phenotypic plasticity in conferring invasive behavior because traits used in comparative studies are often measured in a single environment and by using plants from a single population. To obtain a deeper insight into the role of environmental factors, local differences and competition in plant invasions, we compared species of Impatiens (Balsaminaceae of different origin and invasion status that occur in central Europe: native I. noli-tangere and three alien species (highly invasive I. glandulifera, less invasive I. parviflora and potentially invasive I. capensis. In two experiments we harvested late-stage reproductive plants to estimate performance. The first experiment quantified how populations differed in performance under varying light and moisture levels in the absence of competition. The second experiment quantified performance across these environments in the presence of intra- and inter-specific competition. The highly invasive I. glandulifera was the strongest competitor, was the tallest and produced the greatest biomass. Small size and high plasticity were characteristic for I. parviflora. This species appeared to be the second strongest competitor, especially under low soil moisture. The performance of I. capensis was within the range of the other Impatiens species studied, but sometimes limited by alien competitors. Our results suggest that invasion success within the genus Impatiens depends on the ability to grow large under a range of environmental conditions, including competition. The invasive species also exhibited greater phenotypic plasticity across environmental conditions than the native species. Finally, the decreased performance of the native I. noli-tangere in competition with other

Habitat Modeling of Alien Plant Species at Varying Levels of Occupancy

Directory of Open Access Journals (Sweden)

Jennifer A. Brown

2012-09-01

Full Text Available Distribution models of invasive plants are very useful tools for conservation management. There are challenges in modeling expanding populations, especially in a dynamic environment, and when data are limited. In this paper, predictive habitat models were assessed for three invasive plant species, at differing levels of occurrence, using two different habitat modeling techniques: logistic regression and maximum entropy. The influence of disturbance, spatial and temporal heterogeneity, and other landscape characteristics is assessed by creating regional level models based on occurrence records from the USDA Forest Service’s Forest Inventory and Analysis database. Logistic regression and maximum entropy models were assessed independently. Ensemble models were developed to combine the predictions of the two analysis approaches to obtain a more robust prediction estimate. All species had strong models with Area Under the receiver operator Curve (AUC of >0.75. The species with the highest occurrence, Ligustrum spp., had the greatest agreement between the models (93%. Lolium arundinaceum had the most disagreement between models at 33% and the lowest AUC values. Overall, the strength of integrative modeling in assessing and understanding habitat modeling was demonstrated.

Angular distribution of species in pulsed laser deposition of La{sub x}Ca{sub 1−x}MnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Ojeda-G-P, Alejandro [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen-PSI (Switzerland); Schneider, Christof W., E-mail: christof.schneider@psi.ch [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen-PSI (Switzerland); Döbeli, Max [Ion Beam Physics, ETH Zurich, CH-8093 Zurich (Switzerland); Lippert, Thomas; Wokaun, Alexander [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen-PSI (Switzerland)

2015-05-01

Highlights: • The angular distribution of species was analyzed for different pressures. • Results show a non-congruent transfer of composition from target to substrate. • Film thickness and composition show different angular distributions. - Abstract: The angular distribution of species from a La{sub 0.4}Ca{sub 0.6}MnO{sub 3} target irradiated with a 248 nm nanosecond pulsed laser was investigated by Rutherford backscattering spectrometry for four different Ar pressures. The film thickness angular distribution was also analyzed using profilometry. Depending on the background gas pressure, the target to substrate distance, and the angular location the film thickness and composition varies considerably. In particular the film composition could vary by up to 17% with respect to the composition of the target material.

Insufficient Chilling Effects Vary among Boreal Tree Species and Chilling Duration

Directory of Open Access Journals (Sweden)

Rongzhou Man

2017-08-01

Full Text Available Insufficient chilling resulting from rising winter temperatures associated with climate warming has been an area of particular interest in boreal and temperate regions where a period of cool temperatures in fall and winter is required to break plant dormancy. In this study, we examined the budburst and growth of trembling aspen (Populus tremuloides Michx., balsam poplar (Populus balsamifera L., white birch (Betula papyrifera Marsh., black spruce (Picea mariana (Mill. B.S.P., white spruce (Picea glauca (Moench Voss, jack pine (Pinus banksiana Lamb., and lodgepole pine (Pinus contorta Dougl. ex. Loud. seedlings subjected to typical northern Ontario, Canada, spring conditions in climate chambers after different exposures to natural chilling. Results indicate that chilling requirements (cumulative weighted chilling hours differed substantially among the seven species, ranging from 300 to 500 h for spruce seedlings to more than 1100 h for trembling aspen and lodgepole pine. Only spruce seedlings had fulfilled their chilling requirements before December 31, whereas the other species continued chilling well into March and April. Species with lower chilling requirements needed more heat accumulation for budburst and vice versa. Insufficient chilling delayed budburst but only extremely restricted chilling hours (<400 resulted in abnormal budburst and growth, including reduced needle and shoot expansion, early budburst in lower crowns, and erratic budburst on lower stems and roots. Effects, however, depended on both the species’ chilling requirements and the chilling–heat relationship. Among the seven tree species examined, trembling aspen is most likely to be affected by reduced chilling accumulation possible under future climate scenarios, followed by balsam poplar, white birch, lodgepole pine, and jack pine. Black and white spruce are least likely to be affected by changes in chilling hours.

Volitional components of consciousness vary across wakefulness, dreaming and lucid dreaming

NARCIS (Netherlands)

Dresler, M.; Eibl, L.; Fischer, C.F.; Wehrle, R.; Spoormaker, V.I.; Steiger, A.; Czisch, M.; Pawlowski, M.

2014-01-01

Consciousness is a multifaceted concept; its different aspects vary across species, vigilance states, or health conditions. While basal aspects of consciousness like perceptions and emotions are present in many states and species, higher-order aspects like reflective or volitional capabilities seem

Aquatic macrophyte community varies in urban reservoirs with different degrees of eutrophication

Directory of Open Access Journals (Sweden)

Suelen Cristina Alves da Silva

2014-06-01

Full Text Available AIM: Investigate spatial and temporal variation in the aquatic macrophyte community in four urban reservoirs located in Curitiba metropolitan region, Brazil. We tested the hypothesis that aquatic macrophyte community differ among reservoirs with different degrees of eutrophication. METHODS: The reservoirs selected ranged from oligotrophic/mesotrophic to eutrophic. Sampling occurred in October 2011, January 2012 and June 2012. Twelve aquatic macrophytes stands were sampled at each reservoir. Species were identified and the relative abundance of aquatic macrophytes was estimated. Differences among reservoirs and over sampling periods were analyzed: i through two‑way ANOVAs considering the stand extent (m and the stand biodiversity - species richness, evenness, Shannon-Wiener index and beta diversity (species variation along the aquatic macrophyte stand; and ii through PERMANOVA considering species composition. Indicator species that were characteristic for each reservoir were also identified. RESULTS: The aquatic macrophyte stand extent varied among reservoirs and over sampling periods. Species richness showed only temporal variation. On the other hand, evenness and Shannon-Wiener index varied only among reservoirs. The beta diversity of macrophyte stands did not vary among reservoirs or over time, meaning that species variability among aquatic macrophyte stands was independent of the stand extent and reservoir eutrophication. Community composition depended on the reservoir and sampling period. CONCLUSIONS: Our results support our initial expectation that reservoirs of different degrees of eutrophication have different aquatic macrophyte communities. As a consequence, each reservoir had particular indicator species. Therefore, monitoring and management efforts must be offered for each reservoir individually.

Considerations on the biochemical composition of some freshwater zooplankton species.

Directory of Open Access Journals (Sweden)

Nicoletta RICCARDI

1999-02-01

Full Text Available The mean elemental (C, H, N and biochemical composition (lipids, carbohydrates and proteins of some abundant crustacean zooplankton species of Italian insubric lakes has been estimated by the analysis of samples collected at different seasons from various environments (Lake Maggiore, Lake Varese, Lake Comabbio, Lake Monate. From each sample an adequate number of specimens of each abundant species was sorted and analyzed by a CHN elemental analyzer. The percentage of lipids, carbohydrates and proteins and the calorific content were calculated from the elemental composition according to Gnaiger & Bitterlich (1984. Inter- and intraspecific variability of biochemical composition was quite high, while elemental composition and calorific content were less variable. An estimate of the mean elemental and biochemical composition of each species was obtained by pooling the data. These mean values have been used to estimate the pools of elements and compounds in the crustacean zooplankton of Lake Comabbio to provide an example of the importance of a multiple approach in zooplankton studies.

Dynamics of Mixed- Candida Species Biofilms in Response to Antifungals.

Science.gov (United States)

Vipulanandan, G; Herrera, M; Wiederhold, N P; Li, X; Mintz, J; Wickes, B L; Kadosh, D

2018-01-01

Oral infections caused by Candida species, the most commonly isolated human fungal pathogen, are frequently associated with biofilms. Although Candida albicans is the predominant organism found in patients with oral thrush, a biofilm infection, there is an increasing incidence of oral colonization and infections caused by non- albicans Candida species, including C. glabrata, C. dubliniensis, and C. tropicalis, which are frequently more resistant to antifungal treatment. While single-species Candida biofilms have been well studied, considerably less is known about the dynamics of mixed- Candida species biofilms and how these dynamics are altered by antifungal treatment. To address these questions, we developed a quantitative polymerase chain reaction-based approach to determine the precise species composition of mixed- Candida species biofilms formed by clinical isolates and laboratory strains in the presence and absence of clinically relevant concentrations of 3 commonly used antifungals: fluconazole, caspofungin, and amphotericin B. In monospecies biofilms, fluconazole exposure favored growth of C. glabrata and C. tropicalis, while caspofungin generally favored significant growth of all species to a varying degree. Fluconazole was not effective against preformed mixed- Candida species biofilms while amphotericin B was potent. As a general trend, in mixed- Candida species biofilms, C. albicans lost dominance in the presence of antifungals. Interestingly, presence in mixed versus monospecies biofilms reduced susceptibility to amphotericin B for C. tropicalis and C. glabrata. Overall, our data suggest that antifungal treatment favors the growth of specific non- albicans Candida species in mixed- Candida species biofilms.

Some considerations on robotics for environmental friendliness

International Nuclear Information System (INIS)

Pin, F.G.

1993-01-01

This paper presents a series of considerations regarding the use and potential of robotic devices for supporting humans in a variety of tasks, while maintaining, if not improving, environmental friendliness. One of the main considerations brought forward here relates to the type of human-support functions which the robots are, or will be, expected to perform, and from this, a clear differentiation appears between robots designed to replace humans in environments that were engineered in the past for best human functionality, and robots designed to take functions in the future, in environments which could be better engineered for large-scale human-robot synergy. Other considerations discussed involve the ''life-cycle'' cleanliness of robotic systems, including the materials needs for their construction, their operation, their disposal and, more importantly, their energy consumption which will impact the cycle of natural resources utilization. These considerations are discussed using a variety of possible robotic systems applications in contexts varied as manufacturing, energy recovery and production, emergency situations handling, traffic improvement, waste management, agriculture, and space exploration. In all these applications, the operation costs and complexity of the robots seem to vary in inverse proportion to the amount of engineering that is feasible to make the task environment more robot-friendly, but with no seemingly direct impact on the potential for environmental friendliness of the robots

Some considerations on robotics for environmental friendliness

Energy Technology Data Exchange (ETDEWEB)

Pin, F.G.

1993-12-01

This paper presents a series of considerations regarding the use and potential of robotic devices for supporting humans in a variety of tasks, while maintaining, if not improving, environmental friendliness. One of the main considerations brought forward here relates to the type of human-support functions which the robots are, or will be, expected to perform, and from this, a clear differentiation appears between robots designed to replace humans in environments that were engineered in the past for best human functionality, and robots designed to take functions in the future, in environments which could be better engineered for large-scale human-robot synergy. Other considerations discussed involve the ``life-cycle`` cleanliness of robotic systems, including the materials needs for their construction, their operation, their disposal and, more importantly, their energy consumption which will impact the cycle of natural resources utilization. These considerations are discussed using a variety of possible robotic systems applications in contexts varied as manufacturing, energy recovery and production, emergency situations handling, traffic improvement, waste management, agriculture, and space exploration. In all these applications, the operation costs and complexity of the robots seem to vary in inverse proportion to the amount of engineering that is feasible to make the task environment more robot-friendly, but with no seemingly direct impact on the potential for environmental friendliness of the robots.

Lichen Persistence and Recovery in Response to Varied Volcanic Disturbances

Science.gov (United States)

Nelson, P.; Wheeler, T. B.

2015-12-01

Volcanic eruptions produce many ecological disturbances that structure vegetation. While lichens are sensitive to disturbances, little is known about their responses to volcanic disturbances, except for colonization of lava. We examined lichen community responses through time to different disturbances produced by the May 1, 2008 eruption of Volcan Chaiten in south-central Chile. Pre-eruption vegetation near the volcano was old-growth Valdivian temperate rainforest dominated by closed-canopy Nothofagus sp... In 2012, we installed thirteen 1-acre plots across volcanic disturbance zones on which a time-constrained search was done for all macrolichen species, each of which was assigned an approximate log10 categorical abundance. We also installed a 0.2 m2 quadrat on two representative trees per plot for repeat photography of lichen cover. We remeasured at least one plot per disturbance zone in 2014 and re-photographed tree quadrats in 2013 and 2014. We then analyzed species composition and abundance differences among disturbance zones. In 2012, the blast (pyroclastic density flow), scorch (standing scorched forest at the edge of the blast) and deep tephra (>10 cm) zones had the lowest lichen species richness (5-13 species), followed by reference (unimpacted) and shallow (lichen species since 2012 while the light tephra and reference were essentially unchanged. Gravel rain, gravel rain + pumice and flooded forest plots all had about the same number of species in 2014 as 2012. Lichen colonization and growth in tree quadrats varied widely, from very little colonization in the blast to prolific colonization in the gravel rain + pumice zone. Lichen's varied responses to different volcanic disturbances were attributable to varying degrees of mortality and subsequent availability of substrate, quantity of light and removal of competitors. While sensitive to disturbance, lichens are apparently resilient to and can quickly recolonize after a variety of large, violent volcanic

Analysing how plants in coastal wetlands respond to varying tidal regimes throughout their life cycles.

Science.gov (United States)

Xie, Tian; Cui, Baoshan; Li, Shanze

2017-10-15

Important to conserve plant species in coastal wetlands throughout their life cycle. All life stages in these habitats are exposed to varying tidal cycles. It is necessary to investigate all life stages as to how they respond to varying tidal regimes. We examine three wetlands containing populations of an endangered halophyte species, each subjected to different tidal regimes: (1). wetlands completely closed to tidal cycles; (2). wetlands directly exposed to tidal cycles (3). wetlands exposed to a partially closed tidal regime. Our results showed that the most threatened stage varied between wetlands subjected to these varying tidal regimes. We hypothesis that populations of this species have adapted to these different tidal regimes. Such information is useful in developing management options for coastal wetlands and modifying future barriers restricting tidal flushing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oribatid communities and heavy metal bioaccumulation in selected species associated with lichens in a heavily contaminated habitat.

Science.gov (United States)

Skubała, Piotr; Rola, Kaja; Osyczka, Piotr

2016-05-01

The study examines oribatid communities and heavy metal bioaccumulation in selected species associated with different microhabitats of a post-smelting dump, i.e. three lichen species of Cladonia with various growth forms and the slag substrate. The abundance of oribatids collected from the substrate was significantly lower than observed in lichen thalli. The morphology and chemical properties of lichens, and to some extent varying concentrations of heavy metals in thalli, are probably responsible for significant differences in oribatid communities inhabiting different Cladonia species. Some oribatids demonstrate the ability to accumulate zinc and cadmium with unusual efficiency, whereas lead is the most effectively regulated element by all species. A positive correlation was found between Zn content in all studied oribatids and their microhabitats. Oribatids exploring different food resources, i.e. fungivorous and non-fungivorous grazers, show considerable differences in bioconcentrations of certain elements.

Plant trait-species abundance relationships vary with environmental properties in subtropical forests in eastern china.

Directory of Open Access Journals (Sweden)

En-Rong Yan

Full Text Available Understanding how plant trait-species abundance relationships change with a range of single and multivariate environmental properties is crucial for explaining species abundance and rarity. In this study, the abundance of 94 woody plant species was examined and related to 15 plant leaf and wood traits at both local and landscape scales involving 31 plots in subtropical forests in eastern China. Further, plant trait-species abundance relationships were related to a range of single and multivariate (PCA axes environmental properties such as air humidity, soil moisture content, soil temperature, soil pH, and soil organic matter, nitrogen (N and phosphorus (P contents. At the landscape scale, plant maximum height, and twig and stem wood densities were positively correlated, whereas mean leaf area (MLA, leaf N concentration (LN, and total leaf area per twig size (TLA were negatively correlated with species abundance. At the plot scale, plant maximum height, leaf and twig dry matter contents, twig and stem wood densities were positively correlated, but MLA, specific leaf area, LN, leaf P concentration and TLA were negatively correlated with species abundance. Plant trait-species abundance relationships shifted over the range of seven single environmental properties and along multivariate environmental axes in a similar way. In conclusion, strong relationships between plant traits and species abundance existed among and within communities. Significant shifts in plant trait-species abundance relationships in a range of environmental properties suggest strong environmental filtering processes that influence species abundance and rarity in the studied subtropical forests.

Global Stability of Polytopic Linear Time-Varying Dynamic Systems under Time-Varying Point Delays and Impulsive Controls

Directory of Open Access Journals (Sweden)

M. de la Sen

2010-01-01

Full Text Available This paper investigates the stability properties of a class of dynamic linear systems possessing several linear time-invariant parameterizations (or configurations which conform a linear time-varying polytopic dynamic system with a finite number of time-varying time-differentiable point delays. The parameterizations may be timevarying and with bounded discontinuities and they can be subject to mixed regular plus impulsive controls within a sequence of time instants of zero measure. The polytopic parameterization for the dynamics associated with each delay is specific, so that (q+1 polytopic parameterizations are considered for a system with q delays being also subject to delay-free dynamics. The considered general dynamic system includes, as particular cases, a wide class of switched linear systems whose individual parameterizations are timeinvariant which are governed by a switching rule. However, the dynamic system under consideration is viewed as much more general since it is time-varying with timevarying delays and the bounded discontinuous changes of active parameterizations are generated by impulsive controls in the dynamics and, at the same time, there is not a prescribed set of candidate potential parameterizations.

Taxonomic considerations in listing subspecies under the U.S. Endangered Species Act.

Science.gov (United States)

Haig, Susan M; Beever, Erik A; Chambers, Steven M; Draheim, Hope M; Dugger, Bruce D; Dunham, Susie; Elliott-Smith, Elise; Fontaine, Joseph B; Kesler, Dylan C; Knaus, Brian J; Lopes, Iara F; Loschl, Pete; Mullins, Thomas D; Sheffield, Lisa M

2006-12-01

The U.S. Endangered Species Act (ESA) allows listing of subspecies and other groupings below the rank of species. This provides the U.S. Fish and Wildlife Service and the National Marine Fisheries Service with a means to target the most critical unit in need of conservation. Although roughly one-quarter of listed taxa are subspecies, these management agencies are hindered by uncertainties about taxonomic standards during listing or delisting activities. In a review of taxonomic publications and societies, we found few subspecies lists and none that stated standardized criteria for determining subspecific taxa. Lack of criteria is attributed to a centuries-old debate over species and subspecies concepts. Nevertheless, the critical need to resolve this debate for ESA listings led us to propose that minimal biological criteria to define disjunct subspecies (legally or taxonomically) should include the discreteness and significance criteria of distinct population segments (as defined under the ESA). Our subspecies criteria are in stark contrast to that proposed by supporters of the phylogenetic species concept and provide a clear distinction between species and subspecies. Efforts to eliminate or reduce ambiguity associated with subspecies-level classifications will assist with ESA listing decisions. Thus, we urge professional taxonomic societies to publish and periodically update peer-reviewed species and subspecies lists. This effort must be paralleled throughout the world for efficient taxonomic conservation to take place.

A Keystone Ant Species Provides Robust Biological Control of the Coffee Berry Borer Under Varying Pest Densities.

Science.gov (United States)

Morris, Jonathan R; Vandermeer, John; Perfecto, Ivette

2015-01-01

Species' functional traits are an important part of the ecological complexity that determines the provisioning of ecosystem services. In biological pest control, predator response to pest density variation is a dynamic trait that impacts the provision of this service in agroecosystems. When pest populations fluctuate, farmers relying on biocontrol services need to know how natural enemies respond to these changes. Here we test the effect of variation in coffee berry borer (CBB) density on the biocontrol efficiency of a keystone ant species (Azteca sericeasur) in a coffee agroecosystem. We performed exclosure experiments to measure the infestation rate of CBB released on coffee branches in the presence and absence of ants at four different CBB density levels. We measured infestation rate as the number of CBB bored into fruits after 24 hours, quantified biocontrol efficiency (BCE) as the proportion of infesting CBB removed by ants, and estimated functional response from ant attack rates, measured as the difference in CBB infestation between branches. Infestation rates of CBB on branches with ants were significantly lower (71%-82%) than on those without ants across all density levels. Additionally, biocontrol efficiency was generally high and did not significantly vary across pest density treatments. Furthermore, ant attack rates increased linearly with increasing CBB density, suggesting a Type I functional response. These results demonstrate that ants can provide robust biological control of CBB, despite variation in pest density, and that the response of predators to pest density variation is an important factor in the provision of biocontrol services. Considering how natural enemies respond to changes in pest densities will allow for more accurate biocontrol predictions and better-informed management of this ecosystem service in agroecosystems.

Biotechnological production of caffeic acid derivatives from cell and organ cultures of Echinacea species.

Science.gov (United States)

Murthy, Hosakatte Niranjana; Kim, Yun-Soo; Park, So-Young; Paek, Kee-Yoeup

2014-09-01

Caffeic acid derivatives (CADs) are a group of bioactive compounds which are produced in Echinacea species especially Echinacea purpurea, Echinacea angustifolia, and Echinacea pallida. Echinacea is a popular herbal medicine used in the treatment of common cold and it is also a prominent dietary supplement used throughout the world. Caffeic acid, chlorogenic acid (5-O-caffeoylquinic acid), caftaric acid (2-O-caffeoyltartaric acid), cichoric acid (2, 3-O-dicaffeoyltartaric acid), cynarin, and echinacoside are some of the important CADs which have varied pharmacological activities. The concentrations of these bioactive compounds are species specific and also they vary considerably with the cultivated Echinacea species due to geographical location, stage of development, time of harvest, and growth conditions. Due to these reasons, plant cell and organ cultures have become attractive alternative for the production of biomass and caffeic acid derivatives. Adventitious and hairy roots have been induced in E. pupurea and E. angustifolia, and suspension cultures have been established from flask to bioreactor scale for the production of biomass and CADs. Tremendous progress has been made in this area; various bioprocess methods and strategies have been developed for constant high-quality productivity of biomass and secondary products. This review is aimed to discuss biotechnological methods and approaches employed for the sustainable production of CADs.

Seasonal variation of assemblage and feeding guild structure of fish species in a boreal tidal basin

Science.gov (United States)

Kellnreitner, Florian; Pockberger, Moritz; Asmus, Harald

2012-08-01

Species composition, abundance, feeding relationships and guild structure of the fish assemblage in the Sylt-Rømø bight, a tidal basin in the northern Wadden Sea, were investigated to show seasonal differences and the importance of functional groups in this area. The tidal flats and in shallow subtidal areas were sampled using a beach seine and a bottom trawl net was used for deeper subtidal areas and tidal gullies. Species richness of fish was highest in summer where 26 species were caught, while the lowest richness was recorded in winter (17 species). Clear differences in species richness and abundance were found between shallow areas and deeper parts of the bight. Clupea harengus and Ammodytes tobianus were the most abundant species in deeper areas, while Pomatoschistus microps and Pomatoschistus minutus dominated shallower waters. Gut contents of 27 fish species were identified and the guild structure analyzed by UPGMA clustering of niche overlaps. Calanoid copepods (19.9%), Crangon crangon (18.2%) and mysid shrimps (8.4%) were the most abundant prey items of all fish species combined. Seven feeding guilds were present in the fall and winter, and eight and six in spring and summer, respectively. Fish feeding on calanoid copepods and C. crangon were present year round, whereas the occurrence of other guilds varied between seasons. Species composition of prey changed through seasons and, for some fish species, even the feeding mode itself varied with season. Most noticeable, 11 fish species changed guilds between seasons. We found a convergence in summer towards abundant prey items, whereas in winter diet overlap was lower. This is the first investigation of guild structure of almost all fish species present in a Wadden Sea area, and shows that consideration of seasonal differences is essential when determining feeding relationships of fish in temperate areas.

Attitudes as Object-Evaluation Associations of Varying Strength

OpenAIRE

Fazio, Russell H.

2007-01-01

Historical developments regarding the attitude concept are reviewed, and set the stage for consideration of a theoretical perspective that views attitude, not as a hypothetical construct, but as evaluative knowledge. A model of attitudes as object-evaluation associations of varying strength is summarized, along with research supporting the model’s contention that at least some attitudes are represented in memory and activated automatically upon the individual’s encountering the attitude objec...

Risk adjusted receding horizon control of constrained linear parameter varying systems

NARCIS (Netherlands)

Sznaier, M.; Lagoa, C.; Stoorvogel, Antonie Arij; Li, X.

2005-01-01

In the past few years, control of Linear Parameter Varying Systems (LPV) has been the object of considerable attention, as a way of formalizing the intuitively appealing idea of gain scheduling control for nonlinear systems. However, currently available LPV techniques are both computationally

Hierarchical demographic approaches for assessing invasion dynamics of non-indigenous species: An example using northern snakehead (Channa argus)

Science.gov (United States)

Jiao, Y.; Lapointe, N.W.R.; Angermeier, P.L.; Murphy, B.R.

2009-01-01

Models of species' demographic features are commonly used to understand population dynamics and inform management tactics. Hierarchical demographic models are ideal for the assessment of non-indigenous species because our knowledge of non-indigenous populations is usually limited, data on demographic traits often come from a species' native range, these traits vary among populations, and traits are likely to vary considerably over time as species adapt to new environments. Hierarchical models readily incorporate this spatiotemporal variation in species' demographic traits by representing demographic parameters as multi-level hierarchies. As is done for traditional non-hierarchical matrix models, sensitivity and elasticity analyses are used to evaluate the contributions of different life stages and parameters to estimates of population growth rate. We applied a hierarchical model to northern snakehead (Channa argus), a fish currently invading the eastern United States. We used a Monte Carlo approach to simulate uncertainties in the sensitivity and elasticity analyses and to project future population persistence under selected management tactics. We gathered key biological information on northern snakehead natural mortality, maturity and recruitment in its native Asian environment. We compared the model performance with and without hierarchy of parameters. Our results suggest that ignoring the hierarchy of parameters in demographic models may result in poor estimates of population size and growth and may lead to erroneous management advice. In our case, the hierarchy used multi-level distributions to simulate the heterogeneity of demographic parameters across different locations or situations. The probability that the northern snakehead population will increase and harm the native fauna is considerable. Our elasticity and prognostic analyses showed that intensive control efforts immediately prior to spawning and/or juvenile-dispersal periods would be more effective

Flexible time-varying filter banks

Science.gov (United States)

Tuncer, Temel E.; Nguyen, Truong Q.

1993-09-01

Linear phase maximally flat FIR Butterworth filter approximations are discussed and a new filter design method is introduced. This variable cutoff filter design method uses the cosine modulated versions of a prototype filter. The design procedure is simple and different variants of this procedure can be used to obtain close to optimum linear phase filters. Using this method, flexible time-varying filter banks with good reconstruction error are introduced. These types of oversampled filter banks have small magnitude error which can be easily controlled by the appropriate choice of modulation frequency. This error can be further decreased by magnitude equalization without increasing the computational complexity considerably. Two dimensional design examples are also given.

Part 8. Deployment considerations

International Nuclear Information System (INIS)

Dance, K.D.; Chang, Y.I.; Daly, T.A.

1980-01-01

This report addresses considerations of fast breeder reactor development and deployment from a national perspective. Nations vary greatly in their expertise and interest relative to nuclear power, and hence a single set of steps to be taken by a nation in decision-making on breeder development and deployment cannot be presented. The approach taken in this report is to present discussions on key factors influencing the breeder development and deployment decisions, especially in non-breeder nations, by drawing upon historical perspectives of the Light Water Reactor for comparison

Does enemy damage vary across the range of exotic plant species? Evidence from two coastal dune plant species in eastern Australia.

Science.gov (United States)

Tabassum, Samiya; Leishman, Michelle R

2018-02-01

Release from natural enemies is often cited as a key factor for understanding the success of invasive plant species in novel environments. However, with time invasive species will accumulate native enemies in their invaded range, with factors such as spread distance from the site of introduction, climate and leaf-level traits potentially affecting enemy acquisition rates. However, the influence of such factors is difficult to assess without examining enemy attack across the entire species' range. We tested the significance of factors associated with range expansion (distance from source population and maximum population density), climatic variables (annual temperature and rainfall) and leaf-level traits [specific leaf area (SLA) and foliar nitrogen concentration] in explaining variation in enemy damage across multiple populations of two coastal invasive plants (Gladiolus gueinzii Kunze and Hydrocotyle bonariensis Lam.) along their entire introduced distribution in eastern Australia. We found that for H. bonariensis, amount of foliar damage increased with distance from source population. In contrast, for G. gueinzii, probability and amount of foliar damage decreased with decreasing temperature and increasing rainfall, respectively. Our results show that patterns of enemy attack across species' ranges are complex and cannot be generalised between species or even range edges.

Spectral Data Captures Important Variability Between and Among Species and Functional Types

Science.gov (United States)

Townsend, P. A.; Serbin, S. P.; Kingdon, C.; Singh, A.; Couture, J. J.; Gamon, J. A.

2013-12-01

Narrowband spectral data in the visible, near and shortwave infrared (400-2500 nm) are being used increasingly in plant ecology to characterize the biochemical, physiological and water status of vegetation, as well as community composition. In particular, spectroscopic data have recently received considerable attention for their capacity to discriminate plants according to functional properties or 'optical types.' Such measurements can be acquired from airborne/satellite remote sensing imagery or field spectrometers and are commonly used to directly estimate or infer properties important to photosynthesis, carbon and water fluxes, nutrient dynamics, phenology, and disturbance. Spectral data therefore represent proxies for measurements that are otherwise time consuming or expensive to make, and - more importantly - provide the opportunity to characterize the spatial and temporal variability of taxonomic or functional groups. We have found that spectral variation within species and functional types can in fact exceed the variation between types. As such, we recommend that the traditional quantification of characteristics defining species and/or functional types must be modified to include the range of variability in those properties. We provide four examples of the importance of spectral data for describing within-species/functional type variation. First, within temperate forests, the spectral properties of foliage vary considerably with canopy position. This variability is strongly related to differences in specific leaf area between shade- and sun-lit leaves, and the resulting differences among leaves in strategies for light harvesting, photosynthesis, and leaf longevity. These results point to the need to better characterize leaf optical properties throughout a canopy, rather than basing the characterization of ecosystem functioning on only the sunlit portion of the canopy crown. Second, we show considerable differences in optical properties of foliage from

Model analysis of the chemical conversion of exhaust species in the expanding plumes of subsonic aircraft

Energy Technology Data Exchange (ETDEWEB)

Moellhoff, M.; Hendricks, J.; Lippert, E.; Petry, H. [Koeln Univ. (Germany). Inst. fuer Geophysik und Meteorologie; Sausen, R. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

1997-12-31

A box model and two different one-dimensional models are used to investigate the chemical conversion of exhaust species in the dispersing plume of a subsonic aircraft flying at cruise altitude. The effect of varying daytime of release as well as the impact of changing dispersion time is studied with special respect to the aircraft induced O{sub 3} production. Effective emission amounts for consideration in mesoscale and global models are calculated. Simulations with modified photolysis rates are performed to show the sensitivity of the photochemistry to the occurrence of cirrus clouds. (author) 8 refs.

Model analysis of the chemical conversion of exhaust species in the expanding plumes of subsonic aircraft

Energy Technology Data Exchange (ETDEWEB)

Moellhoff, M; Hendricks, J; Lippert, E; Petry, H [Koeln Univ. (Germany). Inst. fuer Geophysik und Meteorologie; Sausen, R [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

1998-12-31

A box model and two different one-dimensional models are used to investigate the chemical conversion of exhaust species in the dispersing plume of a subsonic aircraft flying at cruise altitude. The effect of varying daytime of release as well as the impact of changing dispersion time is studied with special respect to the aircraft induced O{sub 3} production. Effective emission amounts for consideration in mesoscale and global models are calculated. Simulations with modified photolysis rates are performed to show the sensitivity of the photochemistry to the occurrence of cirrus clouds. (author) 8 refs.

Studies on the aroma of different species and strains of Pleurotus measured by GC/MS, sensory analysis and electronic nose

OpenAIRE

Renata Zawirska-Wojtasiak; Marek Siwulski; Sylwia Mildner-Szkudlarz; Erwin Wąsowicz

2009-01-01

The aroma of several strains of Pleurotus ostreatus, Pleurotus citrinopileatus and Pleurotus djamor was studied by GC/MS. Three main mushrooms aroma constituents: 3-octanol, 3-octanone and 1-octen-3-ol were taken into account for quantitative measurements. The highest amount of 1-octen-3-ol was recorded in P. ostreatus, while considerably lower amounts in P. citrinopileatus. Sensory profile analysis as well as the electronic nose also varied between the three species of Pleurotus. Chiral gas ...

Metal concentrations in demersal fish species from Santa Maria Bay, Baja California Sur, Mexico (Pacific coast).

Science.gov (United States)

Jonathan, M P; Aurioles-Gamboa, David; Villegas, Lorena Elizabeth Campos; Bohórquez-Herrera, Jimena; Hernández-Camacho, Claudia J; Sujitha, S B

2015-10-15

Concentrations of 11 trace metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, As, Hg) in 40 fish species from Santa Maria Bay, Baja California Sur, Mexico, the strategically important area for marine mammals and organisms were analyzed. Based on their concentrations the ranking of metals Fe>Zn>Ni>Cr>Mn>Pb>Cu>Co>As>Cd>Hg suggests that organism size, metabolism and feeding habits are correlated with metal concentrations. Local geological formations affect the concentrations of different metals in the aquatic environment and are subsequently transferred to fishes. The correlation analysis suggests that metabolism and nurturing habits impact the concentration of metals. Concentrations of Fe and Mn appear to be influenced by scavenging and absorption processes, which vary by species. The considerable variability in the metal concentrations obtained in different species underscores the importance of regular monitoring. Copyright © 2015 Elsevier Ltd. All rights reserved.

Species rarity: definition, causes, and classification

Science.gov (United States)

Curtis H. Flather; Carolyn Hull Sieg

2007-01-01

In virtually all ecological communities around the world, most species are represented by few individuals, and most individuals come from only a few of the most common species. Why this distribution of species abundances is so regularly observed among different taxonomic sets in geographically diverse systems is a question that has received considerable theoretical and...

VariVis: a visualisation toolkit for variation databases

Directory of Open Access Journals (Sweden)

Smith Timothy D

2008-04-01

Full Text Available Abstract Background With the completion of the Human Genome Project and recent advancements in mutation detection technologies, the volume of data available on genetic variations has risen considerably. These data are stored in online variation databases and provide important clues to the cause of diseases and potential side effects or resistance to drugs. However, the data presentation techniques employed by most of these databases make them difficult to use and understand. Results Here we present a visualisation toolkit that can be employed by online variation databases to generate graphical models of gene sequence with corresponding variations and their consequences. The VariVis software package can run on any web server capable of executing Perl CGI scripts and can interface with numerous Database Management Systems and "flat-file" data files. VariVis produces two easily understandable graphical depictions of any gene sequence and matches these with variant data. While developed with the goal of improving the utility of human variation databases, the VariVis package can be used in any variation database to enhance utilisation of, and access to, critical information.

Incorporating Context Dependency of Species Interactions in Species Distribution Models.

Science.gov (United States)

Lany, Nina K; Zarnetske, Phoebe L; Gouhier, Tarik C; Menge, Bruce A

2017-07-01

Species distribution models typically use correlative approaches that characterize the species-environment relationship using occurrence or abundance data for a single species. However, species distributions are determined by both abiotic conditions and biotic interactions with other species in the community. Therefore, climate change is expected to impact species through direct effects on their physiology and indirect effects propagated through their resources, predators, competitors, or mutualists. Furthermore, the sign and strength of species interactions can change according to abiotic conditions, resulting in context-dependent species interactions that may change across space or with climate change. Here, we incorporated the context dependency of species interactions into a dynamic species distribution model. We developed a multi-species model that uses a time-series of observational survey data to evaluate how abiotic conditions and species interactions affect the dynamics of three rocky intertidal species. The model further distinguishes between the direct effects of abiotic conditions on abundance and the indirect effects propagated through interactions with other species. We apply the model to keystone predation by the sea star Pisaster ochraceus on the mussel Mytilus californianus and the barnacle Balanus glandula in the rocky intertidal zone of the Pacific coast, USA. Our method indicated that biotic interactions between P. ochraceus and B. glandula affected B. glandula dynamics across >1000 km of coastline. Consistent with patterns from keystone predation, the growth rate of B. glandula varied according to the abundance of P. ochraceus in the previous year. The data and the model did not indicate that the strength of keystone predation by P. ochraceus varied with a mean annual upwelling index. Balanus glandula cover increased following years with high phytoplankton abundance measured as mean annual chlorophyll-a. M. californianus exhibited the same

Biodiversity hotspots house most undiscovered plant species.

Science.gov (United States)

Joppa, Lucas N; Roberts, David L; Myers, Norman; Pimm, Stuart L

2011-08-09

For most organisms, the number of described species considerably underestimates how many exist. This is itself a problem and causes secondary complications given present high rates of species extinction. Known numbers of flowering plants form the basis of biodiversity "hotspots"--places where high levels of endemism and habitat loss coincide to produce high extinction rates. How different would conservation priorities be if the catalog were complete? Approximately 15% more species of flowering plant are likely still undiscovered. They are almost certainly rare, and depending on where they live, suffer high risks of extinction from habitat loss and global climate disruption. By using a model that incorporates taxonomic effort over time, regions predicted to contain large numbers of undiscovered species are already conservation priorities. Our results leave global conservation priorities more or less intact, but suggest considerably higher levels of species imperilment than previously acknowledged.

Nitrogen-Utilization by Plant-Species from Acid Heathland Soils .2. Growth and Shoot/Root Partitioning of No3- Assimilation at Constant Low Ph and Varying No3-/Nh4+ Ratio

NARCIS (Netherlands)

Troelstra, S.R.; Wagenaar, R.; Smant, W.

1995-01-01

The growth of four heathland species, two grasses (D. flexuosa, M. caerulea) and two dwarf shrubs (C. vulgaris, E. tetralix), was tested in solution culture at pH 4.0 with 2 mol m(-3) N, varying the NO3-/NH4+ ratio up to 40% nitrate. In addition, measurements of NRA, plant chemical composition, and

Growth strategies of tropical tree species: disentangling light and size effects.

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Nadja Rüger

Full Text Available An understanding of the drivers of tree growth at the species level is required to predict likely changes of carbon stocks and biodiversity when environmental conditions change. Especially in species-rich tropical forests, it is largely unknown how species differ in their response of growth to resource availability and individual size. We use a hierarchical bayesian approach to quantify the impact of light availability and tree diameter on growth of 274 woody species in a 50-ha long-term forest census plot in Barro Colorado Island, Panama. Light reaching each individual tree was estimated from yearly vertical censuses of canopy density. The hierarchical bayesian approach allowed accounting for different sources of error, such as negative growth observations, and including rare species correctly weighted by their abundance. All species grew faster at higher light. Exponents of a power function relating growth to light were mostly between 0 and 1. This indicates that nearly all species exhibit a decelerating increase of growth with light. In contrast, estimated growth rates at standardized conditions (5 cm dbh, 5% light varied over a 9-fold range and reflect strong growth-strategy differentiation between the species. As a consequence, growth rankings of the species at low (2% and high light (20% were highly correlated. Rare species tended to grow faster and showed a greater sensitivity to light than abundant species. Overall, tree size was less important for growth than light and about half the species were predicted to grow faster in diameter when bigger or smaller, respectively. Together light availability and tree diameter only explained on average 12% of the variation in growth rates. Thus, other factors such as soil characteristics, herbivory, or pathogens may contribute considerably to shaping tree growth in the tropics.

Mode of action human relevance (species concordance) framework: Evolution of the Bradford Hill considerations and comparative analysis of weight of evidence

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Meek, M E (Bette); Palermo, Christine M; Bachman, Ammie N; North, Colin M; Jeffrey Lewis, R

2014-01-01

The mode of action human relevance (MOA/HR) framework increases transparency in systematically considering data on MOA for end (adverse) effects and their relevance to humans. This framework continues to evolve as experience increases in its application. Though the MOA/HR framework is not designed to address the question of “how much information is enough” to support a hypothesized MOA in animals or its relevance to humans, its organizing construct has potential value in considering relative weight of evidence (WOE) among different cases and hypothesized MOA(s). This context is explored based on MOA analyses in published assessments to illustrate the relative extent of supporting data and their implications for dose–response analysis and involved comparisons for chemical assessments on trichloropropane, and carbon tetrachloride with several hypothesized MOA(s) for cancer. The WOE for each hypothesized MOA was summarized in narrative tables based on comparison and contrast of the extent and nature of the supporting database versus potentially inconsistent or missing information. The comparison was based on evolved Bradford Hill considerations rank ordered to reflect their relative contribution to WOE determinations of MOA taking into account increasing experience in their application internationally. This clarification of considerations for WOE determinations as a basis for comparative analysis is anticipated to contribute to increasing consistency in the application of MOA/HR analysis and potentially, transparency in separating science judgment from public policy considerations in regulatory risk assessment. Copyright © 2014. The Authors. Journal of Applied Toxicology Published by John Wiley & Sons Ltd. The potential value of the mode of action (MOA)/human relevance (species concordance) framework in considering relative weight of evidence (WOE) amongst different cases and hypothesized MOA(s) is explored based on the content of several published assessments

Seabird species vary in behavioural response to drone census.

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Brisson-Curadeau, Émile; Bird, David; Burke, Chantelle; Fifield, David A; Pace, Paul; Sherley, Richard B; Elliott, Kyle H

2017-12-20

Unmanned aerial vehicles (UAVs) provide an opportunity to rapidly census wildlife in remote areas while removing some of the hazards. However, wildlife may respond negatively to the UAVs, thereby skewing counts. We surveyed four species of Arctic cliff-nesting seabirds (glaucous gull Larus hyperboreus, Iceland gull Larus glaucoides, common murre Uria aalge and thick-billed murre Uria lomvia) using a UAV and compared censusing techniques to ground photography. An average of 8.5% of murres flew off in response to the UAV, but >99% of those birds were non-breeders. We were unable to detect any impact of the UAV on breeding success of murres, except at a site where aerial predators were abundant and several birds lost their eggs to predators following UAV flights. Furthermore, we found little evidence for habituation by murres to the UAV. Most gulls flew off in response to the UAV, but returned to the nest within five minutes. Counts of gull nests and adults were similar between UAV and ground photography, however the UAV detected up to 52.4% more chicks because chicks were camouflaged and invisible to ground observers. UAVs provide a less hazardous and potentially more accurate method for surveying wildlife. We provide some simple recommendations for their use.

Incorporating evolutionary insights to improve ecotoxicology for freshwater species

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Brady, Steven P.; Richardson, Jonathan L.; Kunz, Bethany K.

2017-01-01

Ecotoxicological studies have provided extensive insights into the lethal and sublethal effects of environmental contaminants. These insights are critical for environmental regulatory frameworks, which rely on knowledge of toxicity for developing policies to manage contaminants. While varied approaches have been applied to ecotoxicological questions, perspectives related to the evolutionary history of focal species or populations have received little consideration. Here, we evaluate chloride toxicity from the perspectives of both macroevolution and contemporary evolution. First, by mapping chloride toxicity values derived from the literature onto a phylogeny of macroinvertebrates, fish, and amphibians, we tested whether macroevolutionary relationships across species and taxa are predictive of chloride tolerance. Next, we conducted chloride exposure tests for two amphibian species to assess whether potential contemporary evolutionary change associated with environmental chloride contamination influences chloride tolerance across local populations. We show that explicitly evaluating both macroevolution and contemporary evolution can provide important and even qualitatively different insights from those obtained via traditional ecotoxicological studies. While macroevolutionary perspectives can help forecast toxicological end points for species with untested sensitivities, contemporary evolutionary perspectives demonstrate the need to consider the environmental context of exposed populations when measuring toxicity. Accounting for divergence among populations of interest can provide more accurate and relevant information related to the sensitivity of populations that may be evolving in response to selection from contaminant exposure. Our data show that approaches accounting for and specifically examining variation among natural populations should become standard practice in ecotoxicology.

Estimating Effects of Species Interactions on Populations of Endangered Species.

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Roth, Tobias; Bühler, Christoph; Amrhein, Valentin

2016-04-01

Global change causes community composition to change considerably through time, with ever-new combinations of interacting species. To study the consequences of newly established species interactions, one available source of data could be observational surveys from biodiversity monitoring. However, approaches using observational data would need to account for niche differences between species and for imperfect detection of individuals. To estimate population sizes of interacting species, we extended N-mixture models that were developed to estimate true population sizes in single species. Simulations revealed that our model is able to disentangle direct effects of dominant on subordinate species from indirect effects of dominant species on detection probability of subordinate species. For illustration, we applied our model to data from a Swiss amphibian monitoring program and showed that sizes of expanding water frog populations were negatively related to population sizes of endangered yellow-bellied toads and common midwife toads and partly of natterjack toads. Unlike other studies that analyzed presence and absence of species, our model suggests that the spread of water frogs in Central Europe is one of the reasons for the decline of endangered toad species. Thus, studying population impacts of dominant species on population sizes of endangered species using data from biodiversity monitoring programs should help to inform conservation policy and to decide whether competing species should be subject to population management.

Intraspecific variability and reaction norms of forest understory plant species traits

Science.gov (United States)

Burton, Julia I.; Perakis, Steven; McKenzie, Sean C.; Lawrence, Caitlin E.; Puettmann, Klaus J.

2017-01-01

Trait-based models of ecological communities typically assume intraspecific variation in functional traits is not important, though such variation can change species trait rankings along gradients in resources and environmental conditions, and thus influence community structure and function.We examined the degree of intraspecific relative to interspecific variation, and reaction norms of 11 functional traits for 57 forest understory plant species, including: intrinsic water-use efficiency (iWUE), Δ15N, 5 leaf traits, 2 stem traits and 2 root traits along gradients in light, nitrogen, moisture and understory cover.Our results indicate that interspecific trait variation exceeded intraspecific variation by at least 50% for most, but not all traits. Intraspecific variation in Δ15N, iWUE, leaf nitrogen content and root traits was high (47-70%) compared with most leaf traits and stem traits (13-38%).Δ15N varied primarily along gradients in abiotic conditions, while light and understory cover were relatively less important. iWUE was related primarily to light transmission, reflecting increases in photosynthesis relative to stomatal conductance. Leaf traits varied mainly as a function of light availability, with some reaction norms depending on understory cover. Plant height increased with understory cover, while stem specific density was related primarily to light. Resources, environmental conditions and understory cover did not contribute strongly to the observed variation in root traits.Gradients in resources, environmental conditions and competition all appear to control intraspecific variability in most traits to some extent. However, our results suggest that species cross-over (i.e., trait rank reversals) along the gradients measured here are generally not a concern.Intraspecific variability in understory plant species traits can be considerable. However, trait data collected under a narrow range of environmental conditions appears sufficient to establish species

Harbour porpoise distribution can vary at small spatiotemporal scales in energetic habitats

Science.gov (United States)

Benjamins, Steven; van Geel, Nienke; Hastie, Gordon; Elliott, Jim; Wilson, Ben

2017-07-01

Marine habitat heterogeneity underpins species distribution and can be generated through interactions between physical and biological drivers at multiple spatiotemporal scales. Passive acoustic monitoring (PAM) is used worldwide to study potential impacts of marine industrial activities on cetaceans, but understanding of animals' site use at small spatiotemporal scales (marine renewable energy development (MRED) sites was investigated by deploying dense arrays of C-POD passive acoustic detectors at a wave energy test site (the European Marine Energy Centre [Billia Croo, Orkney]) and by a minor tidal-stream site (Scarba [Inner Hebrides]). Respective arrays consisted of 7 and 11 moorings containing two C-PODs each and were deployed for up to 55 days. Minimum inter-mooring distances varied between 300-600 m. All C-POD data were analysed at a temporal resolution of whole minutes, with each minute classified as 1 or 0 on the basis of presence/absence of porpoise click trains (Porpoise-Positive Minutes/PPMs). Porpoise detection rates were analysed using Generalised Additive Models (GAMs) with Generalised Estimation Equations (GEEs). Although there were many porpoise detections (wave test site: N=3,432; tidal-stream site: N=17,366), daily detection rates varied significantly within both arrays. Within the wave site array (<1 km diameter), average daily detection rates varied from 4.3 to 14.8 PPMs/day. Within the tidal-stream array (<2 km diameter), average daily detection rates varied from 10.3 to 49.7 PPMs/day. GAM-GEE model results for individual moorings within both arrays indicated linkages between porpoise presence and small-scale heterogeneity among different environmental covariates (e.g., tidal phase, time of day). Porpoise detection rates varied considerably but with coherent patterns between moorings only several hundred metres apart and within hours. These patterns presumably have ecological relevance. These results indicate that, in energetically active and

Isolation and identification of oedogonium species and strains for biomass applications.

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Rebecca J Lawton

Full Text Available Freshwater macroalgae from the genus Oedogonium have recently been targeted for biomass applications; however, strains of Oedogonium for domestication have not yet been identified. Therefore, the objective of this study was to compare the performance of isolates of Oedogonium collected from multiple geographic locations under varying environmental conditions. We collected and identified wild-type isolates of Oedogonium from three geographic locations in Eastern Australia, then measured the growth of these isolates under a range of temperature treatments corresponding to ambient conditions in each geographic location. Our sampling identified 11 isolates of Oedogonium that could be successfully maintained under culture conditions. It was not possible to identify most isolates to species level using DNA barcoding techniques or taxonomic keys. However, there were considerable genetic and morphological differences between isolates, strongly supporting each being an identifiable species. Specific growth rates of species were high (>26% day-1 under 7 of the 9 temperature treatments (average tested temperature range: 20.9-27.7°C. However, the variable growth rates of species under lower temperature treatments demonstrated that some were better able to tolerate lower temperatures. There was evidence for local adaptation under lower temperature treatments (winter conditions, but not under higher temperature treatments (summer conditions. The high growth rates we recorded across multiple temperature treatments for the majority of species confirm the suitability of this diverse genus for biomass applications and the domestication of Oedogonium.

A re-consideration of the taxonomic status of Nebria lacustris Casey (Coleoptera, Carabidae, Nebriini based on multiple datasets – a single species or a species complex?

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David Kavanaugh

2011-11-01

Full Text Available This study gathered evidence from principal component analysis (PCA of morphometric data and molecular analyses of nucleotide sequence data for four nuclear genes (28S, TpI, CAD1, and Wg and two mitochondrial genes (COI and 16S, using parsimony, maximum likelihood, and Bayesian methods. This evidence was combined with morphological and chorological data to re-evaluate the taxonomic status of Nebria lacustris Casey sensu lato. PCA demonstrated that both body size and one conspicuous aspect of pronotal shape vary simultaneously with elevation, latitude, and longitude and served to distinguish populations from the southern Appalachian highlands, south of the French Broad, from all other populations. Molecular analyses revealed surprisingly low overall genetic diversity within N. lacustris sensu lato, with only 0.39% of 4605 bp varied in the concatenated dataset. Evaluation of patterns observed in morphological and genetic variation and distribution led to the following taxonomic conclusions: (1 Nebria lacustris Casey and Nebria bellorum Kavanaugh should be considered distinct species, which is a NEW STATUS for N. bellorum. (2 No other distinct taxonomic subunits could be distinguished with the evidence at hand, but samples from northeastern Iowa, in part of the region known as the “Driftless Zone”, have unique genetic markers for two genes that hint at descent from a local population surviving at least the last glacial advance. (3 No morphometric or molecular evidence supports taxonomic distinction between lowland populations on the shores of Lake Champlain and upland populations in the adjacent Green Mountains of Vermont, despite evident size and pronotal shape differences between many of their members.

Reproductive Impacts of Endocrine-Disrupting Chemicals on Wildlife Species: Implications for Conservation of Endangered Species.

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Tubbs, Christopher W; McDonough, Caitlin E

2018-02-15

Wildlife have proven valuable to our understanding of the potential effects of endocrine-disrupting chemicals (EDCs) on human health by contributing considerably to our understanding of the mechanisms and consequences of EDC exposure. But the threats EDCs present to populations of wildlife species themselves are significant, particularly for endangered species whose existence is vulnerable to any reproductive perturbation. However, few studies address the threats EDCs pose to endangered species owing to challenges associated with their study. Here, we highlight those barriers and review the available literature concerning EDC effects on endangered species. Drawing from other investigations into nonthreatened wildlife species, we highlight opportunities for new approaches to advance our understanding and potentially mitigate the effects of EDCs on endangered species to enhance their fertility.

Trends in breeding phenology across ten decades show varying adjustments to environmental changes in four wader species

DEFF Research Database (Denmark)

Meltofte, Hans; Amstrup, Ole; Petersen, Troels Leuenhagen

2018-01-01

Capsule: During 1928–2016, initiation of egg-laying advanced in two wader species, remained unchanged in one, and was delayed in one species. The changes across years and variation among species can be explained by climatic variables and differences in migratory strategies. Aims: To document...... possible changes in initiation of egg-laying in common Danish wader species since the early part of the 20th century and seek possible correlations between egg-laying, timing of arrival and environmental factors. Methods: Annual records of the first eggs and chicks found on the scientific reserve...... of Tipperne in western Denmark 1928–2016 were analysed using linear regression to determine patterns in timing of egg-laying, pre-breeding length and influence of climate factors. Results: Two short/medium-distance migrant wader species, Northern Lapwing Vanellus vanellus and Common Redshank Tringa totanus...

Relative tolerance of a range of Australian native plant species and lettuce to copper, zinc, cadmium, and lead.

Science.gov (United States)

Lamb, Dane T; Ming, Hui; Megharaj, Mallavarapu; Naidu, Ravi

2010-10-01

The tolerance of wild flora to heavy-metal exposure has received very little research. In this study, the tolerance of four native tree species, four native grass species, and lettuce to copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) was investigated in a root-elongation study using Petri dishes. The results of these studies show a diverse range of responses to Cu, Zn, Cd, and Pb amongst the tested plant species. Toxicity among metals decreased in the following order: Cd ~ Cu > Pb > Zn. Metal concentrations resulting in a 50% reduction in growth (EC(50)) varied considerably, ranging from (microM) 30 (Dichanthium sericeum) to >2000 (Acacia spp.) for Cu; from 260 (Lactuca sativa) to 2000 (Acacia spp.) for Zn; from 27 (L. sativa) to 940 (Acacia holosericea) for Cd; and from 180 (L. sativa) to >1000 (Acacia spp.) for Pb. Sensitive native plant species identified included D. sericeum, Casuarina cunninghamiana, and Austrodanthonia caespitosa. However, L. sativa (lettuce) was also among the most sensitive to all four metals. Acacia species showed a high tolerance to metal exposure, suggesting that the Acacia genus shows potential for use in contaminated-site revegetation.

Variation in biofouling on different species of Indian timbers

Digital Repository Service at National Institute of Oceanography (India)

Raveendran, T.V.; Wagh, A.B.

Biofouling on twenty species of wood exposed in waters of Mormugao Harbour, Goa, India have been presented. Macrofouling biomass varied from species to species. Maximum biomass was recorded on Artocarpus chaplasha (4 kg/m2) and minimum on Hopea...

Three new species of tiger beetles and new data on Cicindelina species from Angola (Coleoptera: Carabidae: Cicindelinae).

Science.gov (United States)

Serrano, Artur R M; Capela, Rúben A; Oesterle, Andreas

2015-10-15

Three new species of tiger beetles, two of the genus Trichotaenia Rivalier, 1957 and one of the genus Cylindera Westwood, 1831, subgenus Ifasina Jeannel, 1946 are described from Angola. An annotated list of species of Cicindelina sampled in this country is provided also. Records for three species previously unknow from Angola are given: Ophryodera smrzi Werner, 2005, Lophyra clatharta (Dejean, 1825) and Lophyra sumlini Cassola, 1976. Some considerations on the distribution and general ecology of these beetles in Angola are also presented. Further, two dichotomic keys are made available for the identification of Trichotaenia species with marked shoulders and Cylindera (Ifasina) species of western and southwestern Africa, respectively.

Neurally mediated airway constriction in human and other species: a comparative study using precision-cut lung slices (PCLS.

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Marco Schlepütz

Full Text Available The peripheral airway innervation of the lower respiratory tract of mammals is not completely functionally characterized. Recently, we have shown in rats that precision-cut lung slices (PCLS respond to electric field stimulation (EFS and provide a useful model to study neural airway responses in distal airways. Since airway responses are known to exhibit considerable species differences, here we examined the neural responses of PCLS prepared from mice, rats, guinea pigs, sheep, marmosets and humans. Peripheral neurons were activated either by EFS or by capsaicin. Bronchoconstriction in response to identical EFS conditions varied between species in magnitude. Frequency response curves did reveal further species-dependent differences of nerve activation in PCLS. Atropine antagonized the EFS-induced bronchoconstriction in human, guinea pig, sheep, rat and marmoset PCLS, showing cholinergic responses. Capsaicin (10 µM caused bronchoconstriction in human (4 from 7 and guinea pig lungs only, indicating excitatory non-adrenergic non-cholinergic responses (eNANC. However, this effect was notably smaller in human responder (30 ± 7.1% than in guinea pig (79 ± 5.1% PCLS. The transient receptor potential (TRP channel blockers SKF96365 and ruthenium red antagonized airway contractions after exposure to EFS or capsaicin in guinea pigs. In conclusion, the different species show distinct patterns of nerve-mediated bronchoconstriction. In the most common experimental animals, i.e. in mice and rats, these responses differ considerably from those in humans. On the other hand, guinea pig and marmoset monkey mimic human responses well and may thus serve as clinically relevant models to study neural airway responses.

Vibration condition monitoring of planetary gearbox under varying external load

Energy Technology Data Exchange (ETDEWEB)

Bartelmus, W.; Zimroz, R. [Wroclaw University of Technology, Wroclaw (Poland)

2009-01-15

The paper shows that for condition monitoring of planetary gearboxes it is important to identify the external varying load condition. In the paper, systematic consideration has been taken of the influence of many factors on the vibration signals generated by a system in which a planetary gearbox is included. These considerations give the basis for vibration signal interpretation, development of the means of condition monitoring, and for the scenario of the degradation of the planetary gearbox. Real measured vibration signals obtained in the industrial environment are processed. The signals are recorded during normal operation of the diagnosed objects, namely planetary gearboxes, which are a part of the driving system used in a bucket wheel excavator, used in lignite mines. It has been found that the most important factor of the proper planetary gearbox condition is connected with perturbation of arm rotation, where an arm rotation gives rise to a specific vibration signal whose properties are depicted by a short-time Fourier transform (STFT) and Wigner-Ville distribution presented as a time-frequency map. The paper gives evidence that there are two dominant low-frequency causes that influence vibration signal modulation, i.e. the varying load, which comes from the nature of the bucket wheel digging process, and the arm/carrier rotation. These two causes determine the condition of the planetary gearboxes considered.

Spatially-explicit estimation of geographical representation in large-scale species distribution datasets.

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Kalwij, Jesse M; Robertson, Mark P; Ronk, Argo; Zobel, Martin; Pärtel, Meelis

2014-01-01

Much ecological research relies on existing multispecies distribution datasets. Such datasets, however, can vary considerably in quality, extent, resolution or taxonomic coverage. We provide a framework for a spatially-explicit evaluation of geographical representation within large-scale species distribution datasets, using the comparison of an occurrence atlas with a range atlas dataset as a working example. Specifically, we compared occurrence maps for 3773 taxa from the widely-used Atlas Florae Europaeae (AFE) with digitised range maps for 2049 taxa of the lesser-known Atlas of North European Vascular Plants. We calculated the level of agreement at a 50-km spatial resolution using average latitudinal and longitudinal species range, and area of occupancy. Agreement in species distribution was calculated and mapped using Jaccard similarity index and a reduced major axis (RMA) regression analysis of species richness between the entire atlases (5221 taxa in total) and between co-occurring species (601 taxa). We found no difference in distribution ranges or in the area of occupancy frequency distribution, indicating that atlases were sufficiently overlapping for a valid comparison. The similarity index map showed high levels of agreement for central, western, and northern Europe. The RMA regression confirmed that geographical representation of AFE was low in areas with a sparse data recording history (e.g., Russia, Belarus and the Ukraine). For co-occurring species in south-eastern Europe, however, the Atlas of North European Vascular Plants showed remarkably higher richness estimations. Geographical representation of atlas data can be much more heterogeneous than often assumed. Level of agreement between datasets can be used to evaluate geographical representation within datasets. Merging atlases into a single dataset is worthwhile in spite of methodological differences, and helps to fill gaps in our knowledge of species distribution ranges. Species distribution

Anistropically varying conductivity in irreversible electroporation simulations.

Science.gov (United States)

Labarbera, Nicholas; Drapaca, Corina

2017-11-01

One recent area of cancer research is irreversible electroporation (IRE). Irreversible electroporation is a minimally invasive procedure where needle electrodes are inserted into the body to ablate tumor cells with electricity. The aim of this paper is to propose a mathematical model that incorporates a tissue's conductivity increasing more in the direction of the electrical field as this has been shown to occur in experiments. It was necessary to mathematically derive a valid form of the conductivity tensor such that it is dependent on the electrical field direction and can be easily implemented into numerical software. The derivation of a conductivity tensor that can take arbitrary functions for the conductivity in the directions tangent and normal to the electrical field is the main contribution of this paper. Numerical simulations were performed for isotropic-varying and anisotropic-varying conductivities to evaluate the importance of including the electrical field's direction in the formulation for conductivity. By starting from previously published experimental results, this paper derived a general formulation for an anistropic-varying tensor for implementation into irreversible electroporation modeling software. The anistropic-varying tensor formulation allows the conductivity to take into consideration both electrical field direction and magnitude, as opposed to previous published works that only took into account electrical field magnitude. The anisotropic formulation predicts roughly a five percent decrease in ablation size for the monopolar simulation and approximately a ten percent decrease in ablation size for the bipolar simulations. This is a positive result as previously reported results found the isotropic formulation to overpredict ablation size for both monopolar and bipolar simulations. Furthermore, it was also reported that the isotropic formulation overpredicts the ablation size more for the bipolar case than the monopolar case. Thus, our

Phylogeography in Nassarius mud snails: Complex patterns in congeneric species.

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Chuanliang Pu

Full Text Available One major goal for phylogeographical studies is to elucidate respective roles of multiple evolutionary and ecological forces that shape the current distribution patterns. In marine and coastal ecosystems, it has been generated a common realization that species with enormous population size and pelagic larval stages can disperse across broad geographical scales, leading to weak or even no phylogeographical structure across large geographical scales. However, the violation of such realization has been frequently reported, and it remains largely unexplored on mechanisms responsible for various phylogeographical patterns observed in different species at varied geographical scales. Here, we used a species-rich genus Nassarius to assess and compare phylogeographical patterns in congeneric species, and discuss causes and consequences underlying varied phylogeographical patterns. Interestingly, we observed complex phylogeographical patterns both within single species and across multiple species, and multiple analyses showed varied levels of genetic heterogeneity among sites within and across species. Available evidence suggests that related species with similar biological characteristics may not be necessary to result in consistent phylogeographical patterns. Multiple factors, including larval ecology, interactions between dispersal and natural selection, and human activity-mediated dispersal, can partially explain the complex patterns observed in this study. Deep investigations should be performed on these factors, particularly their respective roles in determining evolutionary/ecological processes to form phylogeographical patterns in species with high dispersal capacities in marine and coastal ecosystems.

Photosynthetic responses of C3 and C4 species to seasonal water variability and competition.

Science.gov (United States)

Niu, Shuli; Yuan, Zhiyou; Zhang, Yanfang; Liu, Weixing; Zhang, Lei; Huang, Jianhui; Wan, Shiqiang

2005-11-01

This study examined the impacts of seasonal water variability and interspecific competition on the photosynthetic characteristics of a C3 (Leymus chinensis) and a C4 (Chloris virgata) grass species. Plants received the same amount of water but in three seasonal patterns, i.e. the one-peak model (more water in the summer than in the spring and autumn), the two-peak model (more water in the spring and autumn than in the summer), and the average model (water evenly distributed over the growing season). The effects of water variability on the photosynthetic characteristics of the C3 and C4 species were dependent on season. There were significant differences in the photosynthetic characteristics of the C4 species in the summer and the C3 species in the autumn among the three water treatments. Interspecific competition exerted negative impacts on the C3 species in August and September but had no effects on the C4 species in any of the four measuring dates. The relative competitive capability of the two species was not altered by water availability. The assimilation rate, the maximum quantum yield of net CO2 assimilation, and the maximum rate of carboxylation of the C3 species were 13-56%, 5-11%, and 11-48% greater, respectively, in a monoculture than in a mixture in August and September. The results demonstrated that the photosynthetic characteristics of the C3 and C4 species were affected by water availability, but the effects varied considerably with season.

Current Practices in Global/International Advanced Pharmacy Practice Experiences: Preceptor and Student Considerations.

Science.gov (United States)

Dornblaser, Emily K; Ratka, Anna; Gleason, Shaun E; Ombengi, David N; Tofade, Toyin; Wigle, Patricia R; Zapantis, Antonia; Ryan, Melody; Connor, Sharon; Jonkman, Lauren J; Ochs, Leslie; Jungnickel, Paul W; Abrons, Jeanine P; Alsharif, Naser Z

2016-04-25

The objective of this article is to describe the key areas of consideration for global/international advanced pharmacy practice experience (G/I APPE) preceptors, students and learning objectives. At the 2013 Annual Meeting of the American Association of Colleges of Pharmacy (AACP), the GPE SIG prepared and presented an initial report on the G/IAPPE initiatives. Round table discussions were conducted at the 2014 AACP Annual Meeting to document GPE SIG member input on key areas in the report. Literature search of PubMed, Google Scholar and EMBASE with keywords was conducted to expand this report. In this paper, considerations related to preceptors and students and learning outcomes are described. Preceptors for G/I APPEs may vary based on the learning outcomes of the experience. Student learning outcomes for G/I APPEs may vary based on the type of experiential site. Recommendations and future directions for development of G/IAPPEs are presented. Development of a successful G/I APPE requires significant planning and consideration of appropriate qualifications for preceptors and students.

Ethical considerations for field research on fishes

Directory of Open Access Journals (Sweden)

Rhett H. Bennett

2016-12-01

Full Text Available Collection of data from animals for research purposes can negatively impact target or by-catch species if suitable animal ethics practices are not followed. This study aimed to assess the ethical requirements of peer-reviewed scientific journals that publish primary literature on fishes, and review the ethical considerations and animal care guidelines of national and international documents on the ethical treatment of animals for research, to provide an overview of the general ethical considerations for field research on fishes. A review of 250 peer-reviewed, ISI-rated journals publishing primary research on fishes revealed that nearly half (46% had no mention of ethics, treatment of animals or ethical requirements for publication in their author guidelines or publication policies. However, 18% of the journals reviewed identify a specific set of ethical guidelines to be followed before publishing research involving animals. Ethical considerations for investigators undertaking field research on fishes, common to most animal care policies, legislation and guiding documents, include adhering to relevant legislation, minimising sample sizes, reducing or mitigating pain and distress, employing the most appropriate and least invasive techniques and accurately reporting methods and findings. This information will provide potential investigators with a useful starting point for designing and conducting ethical field research. Application of ethical best practices in field sampling studies will improve the welfare of study animals and the conservation of rare and endangered species. Conservation implications: This article provides a list of ethical considerations for designing and conducting field research on fishes. By reviewing sampling techniques and processes that are frequently used in field research on fishes and by highlighting the potential negative impacts of these sampling techniques, this article is intended to assist researchers in planning

Artkunskap och intresse för arter hos blivande lärare för grundskolan. "Student teachers’ knowledge of and interest in species"

Directory of Open Access Journals (Sweden)

Irmeli Palmberg

2012-12-01

Full Text Available According to recent research, the knowledge of species, interest in nature, and nature experiences arethe factors that best promote interest in and understanding of environmental issues and sustainable life style. However, during the past 20 years the knowledge of species has decreased alarmingly among pupils, but also among their teachers. The aim of this study is to make a survey of student teachers’ level of knowledge of species and of factors that have influenced their interest in and capacity for identifying species. Totally 335 student teachers were tested through a species identification test, a questionnaire, and completing interviews. Pupils in grades 7 and 9 and adults were used as reference groups. Student teachers had very varying levels of knowledge of species. Most of them, however, considered it useful to know the most common species of plants and animals in their local environment. The student teachers who had nature-related hobbies as well as practical nature studies in their education, had a considerably better level of knowledge than the others. More than 25 % of the student teachers, however, had a lower level of knowledge (of species than the average pupils ingrades 7 and 9.

Drought tolerance of tropical tree species : functional traits, trade-offs and species distribution

NARCIS (Netherlands)

Markesteijn, L.

2010-01-01

KEY-WORDS:
Bolivia, drought tolerance, shade tolerance, functional traits, trade-offs, ecophysiology, species distribution
Tropical forests occur under rainfall regimes that vary greatly in the rainfall pattern and frequency and intensity of drought. Consequently water availability is

Absorption of some mineral salts by root system of different woody species and accumulation over a whole vegetative cycle (1963)

International Nuclear Information System (INIS)

Gagnaire, J.; Gerard, J.M.

1963-01-01

The concentration power of plant tissues and the translocation speed of mineral salts are considerably varying with the absorbed salt, the botanical species, the considered tissue and the part of the vegetative cycle. In Grenoble, with Picea excelsa, the 'true dormancy' is short (half-november, end of december). It is accompanied by a pre-dormancy period (October, half-november) and a post dormancy period (January, february, march). In vegetative period, Picea excelsa leaves are less concentrating mineral salt than Acer campestris leaves (coefficient 2 for calcium - 3 for phosphates) and Populus nigra leaves (coefficient 3 for calcium, coefficient 5 for phosphates). (author) [fr

Species-area relationships are controlled by species traits.

Science.gov (United States)

Franzén, Markus; Schweiger, Oliver; Betzholtz, Per-Eric

2012-01-01

The species-area relationship (SAR) is one of the most thoroughly investigated empirical relationships in ecology. Two theories have been proposed to explain SARs: classical island biogeography theory and niche theory. Classical island biogeography theory considers the processes of persistence, extinction, and colonization, whereas niche theory focuses on species requirements, such as habitat and resource use. Recent studies have called for the unification of these two theories to better explain the underlying mechanisms that generates SARs. In this context, species traits that can be related to each theory seem promising. Here we analyzed the SARs of butterfly and moth assemblages on islands differing in size and isolation. We tested whether species traits modify the SAR and the response to isolation. In addition to the expected overall effects on the area, traits related to each of the two theories increased the model fit, from 69% up to 90%. Steeper slopes have been shown to have a particularly higher sensitivity to area, which was indicated by species with restricted range (slope = 0.82), narrow dietary niche (slope= 0.59), low abundance (slope= 0.52), and low reproductive potential (slope = 0.51). We concluded that considering species traits by analyzing SARs yields considerable potential for unifying island biogeography theory and niche theory, and that the systematic and predictable effects observed when considering traits can help to guide conservation and management actions.

To sing or not to sing: seasonal changes in singing vary with personality in wild great tits

NARCIS (Netherlands)

Naguib, M.; van Rooij, E.P.; Snijders, L.; van Oers, K.

Expression of sexually selected signals in many species varies over time of day and season. A key model system to study this variation in signal expression is birdsong. Yet, despite good ecological understanding of why song varies across time of day and season, much of the individual variation

Role of functionally dominant species in varying environmental regimes: evidence for the performance-enhancing effect of biodiversity.

Science.gov (United States)

Langenheder, Silke; Bulling, Mark T; Prosser, James I; Solan, Martin

2012-07-30

Theory suggests that biodiversity can act as a buffer against disturbances and environmental variability via two major mechanisms: Firstly, a stabilising effect by decreasing the temporal variance in ecosystem functioning due to compensatory processes; and secondly, a performance enhancing effect by raising the level of community response through the selection of better performing species. Empirical evidence for the stabilizing effect of biodiversity is readily available, whereas experimental confirmation of the performance-enhancing effect of biodiversity is sparse. Here, we test the effect of different environmental regimes (constant versus fluctuating temperature) on bacterial biodiversity-ecosystem functioning relations. We show that positive effects of species richness on ecosystem functioning are enhanced by stronger temperature fluctuations due to the increased performance of individual species. Our results provide evidence for the performance enhancing effect and suggest that selection towards functionally dominant species is likely to benefit the maintenance of ecosystem functioning under more variable conditions.

Risk assessment considerations with regard to the potential impacts of pesticides on endangered species.

Science.gov (United States)

Brain, Richard A; Teed, R Scott; Bang, JiSu; Thorbek, Pernille; Perine, Jeff; Peranginangin, Natalia; Kim, Myoungwoo; Valenti, Ted; Chen, Wenlin; Breton, Roger L; Rodney, Sara I; Moore, Dwayne R J

2015-01-01

Simple, deterministic screening-level assessments that are highly conservative by design facilitate a rapid initial screening to determine whether a pesticide active ingredient has the potential to adversely affect threatened or endangered species. If a worst-case estimate of pesticide exposure is below a very conservative effects metric (e.g., the no observed effects concentration of the most sensitive tested surrogate species) then the potential risks are considered de minimis and unlikely to jeopardize the existence of a threatened or endangered species. Thus by design, such compounded layers of conservatism are intended to minimize potential Type II errors (failure to reject a false null hypothesis of de minimus risk), but correspondingly increase Type I errors (falsely reject a null hypothesis of de minimus risk). Because of the conservatism inherent in screening-level risk assessments, higher-tier scientific information and analyses that provide additional environmental realism can be applied in cases where a potential risk has been identified. This information includes community-level effects data, environmental fate and exposure data, monitoring data, geospatial location and proximity data, species biology data, and probabilistic exposure and population models. Given that the definition of "risk" includes likelihood and magnitude of effect, higher-tier risk assessments should use probabilistic techniques that more accurately and realistically characterize risk. Moreover, where possible and appropriate, risk assessments should focus on effects at the population and community levels of organization rather than the more traditional focus on the organism level. This document provides a review of some types of higher-tier data and assessment refinements available to more accurately and realistically evaluate potential risks of pesticide use to threatened and endangered species. © 2014 SETAC.

Fluctuating interaction network and time-varying stability of a natural fish community

Science.gov (United States)

Ushio, Masayuki; Hsieh, Chih-Hao; Masuda, Reiji; Deyle, Ethan R.; Ye, Hao; Chang, Chun-Wei; Sugihara, George; Kondoh, Michio

2018-02-01

Ecological theory suggests that large-scale patterns such as community stability can be influenced by changes in interspecific interactions that arise from the behavioural and/or physiological responses of individual species varying over time. Although this theory has experimental support, evidence from natural ecosystems is lacking owing to the challenges of tracking rapid changes in interspecific interactions (known to occur on timescales much shorter than a generation time) and then identifying the effect of such changes on large-scale community dynamics. Here, using tools for analysing nonlinear time series and a 12-year-long dataset of fortnightly collected observations on a natural marine fish community in Maizuru Bay, Japan, we show that short-term changes in interaction networks influence overall community dynamics. Among the 15 dominant species, we identify 14 interspecific interactions to construct a dynamic interaction network. We show that the strengths, and even types, of interactions change with time; we also develop a time-varying stability measure based on local Lyapunov stability for attractor dynamics in non-equilibrium nonlinear systems. We use this dynamic stability measure to examine the link between the time-varying interaction network and community stability. We find seasonal patterns in dynamic stability for this fish community that broadly support expectations of current ecological theory. Specifically, the dominance of weak interactions and higher species diversity during summer months are associated with higher dynamic stability and smaller population fluctuations. We suggest that interspecific interactions, community network structure and community stability are dynamic properties, and that linking fluctuating interaction networks to community-level dynamic properties is key to understanding the maintenance of ecological communities in nature.

Power quality improvement in highly varying loads using thyristor-switched capacitor

Energy Technology Data Exchange (ETDEWEB)

Poshtan, M. [Petroleum Inst., Abu Dhabi (United Arab Emirates). Dept. of Electrical Engineering; Mokhtari, H.; Esmaeili, A. [Sharif Univ. of Technology, Tehran (Iran, Islamic Republic of). Dept. of Electrical Engineering

2007-07-01

Ordinary contactor-based-capacitor (CBC) banks may not be able to response quickly enough in highly varying electrical loads such as welding machines or arc furnace loads. Thyristor-switched capacitor (TSC) banks are therefore used to compensate for reactive power of highly varying loads. In this paper, the performance of a TSC was compared to CBC banks. The 2 systems, were also compared in terms of energy saving in transmission systems. Simulations carried out using PSCAD/EMTDC software showed that there was a considerable difference in the performance of the 2 systems. The shortcomings of existing CBC systems include slow response of mechanical switching systems; problem of switching more than one bank into the system; and, voltage/current transients during on-off switching. 3 refs., 6 tabs., 14 figs.

Effects of varying laser trimming geometries on thin film\\ud resistors

OpenAIRE

Alafogianni, Maria; Birkett, Martin; Penlington, Roger

2017-01-01

Purpose - This paper studies the effects of varying laser trim patterns on several performance parameters of thin film resistors such as the temperature coefficient of resistance (TCR) and target resistance value.\\ud \\ud Design/methodology/approach - The benefits and limitations of basic trim patterns are taken into consideration and the plunge cut, double plunge cut and the curved L-cut were selected to be modelled and tested experimentally. A computer simulation of the laser trim patterns h...

Multiscale perspectives of species richness in East Africa

NARCIS (Netherlands)

Said, M.

2003-01-01

This dissertation describes and analyses animal species richness in East Africa from a multi-scale perspective. We studied diversity patterns at sub-continental, national and sub-national level. The study demonstrated that species diversity patterns were scale-dependent. Diversity patterns varied

Epigenetic considerations in aquaculture

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Mackenzie R. Gavery

2017-12-01

Full Text Available Epigenetics has attracted considerable attention with respect to its potential value in many areas of agricultural production, particularly under conditions where the environment can be manipulated or natural variation exists. Here we introduce key concepts and definitions of epigenetic mechanisms, including DNA methylation, histone modifications and non-coding RNA, review the current understanding of epigenetics in both fish and shellfish, and propose key areas of aquaculture where epigenetics could be applied. The first key area is environmental manipulation, where the intention is to induce an ‘epigenetic memory’ either within or between generations to produce a desired phenotype. The second key area is epigenetic selection, which, alone or combined with genetic selection, may increase the reliability of producing animals with desired phenotypes. Based on aspects of life history and husbandry practices in aquaculture species, the application of epigenetic knowledge could significantly affect the productivity and sustainability of aquaculture practices. Conversely, clarifying the role of epigenetic mechanisms in aquaculture species may upend traditional assumptions about selection practices. Ultimately, there are still many unanswered questions regarding how epigenetic mechanisms might be leveraged in aquaculture.

Mycorrhizal association of some agroforestry tree species in two ...

African Journals Online (AJOL)

Mycorrhizal colonization of different agroforestry tree species in two social forestry nurseries was investigated. Percentage of Arbuscular mycorrhizal (AM) infection, number of resting spores and AM fungi species varies both in tree species as well as in two different nurseries. This variation is attributed to various factors such ...

Role of functionally dominant species in varying environmental regimes: evidence for the performance-enhancing effect of biodiversity

Directory of Open Access Journals (Sweden)

Langenheder Silke

2012-07-01

Full Text Available Abstract Background Theory suggests that biodiversity can act as a buffer against disturbances and environmental variability via two major mechanisms: Firstly, a stabilising effect by decreasing the temporal variance in ecosystem functioning due to compensatory processes; and secondly, a performance enhancing effect by raising the level of community response through the selection of better performing species. Empirical evidence for the stabilizing effect of biodiversity is readily available, whereas experimental confirmation of the performance-enhancing effect of biodiversity is sparse. Results Here, we test the effect of different environmental regimes (constant versus fluctuating temperature on bacterial biodiversity-ecosystem functioning relations. We show that positive effects of species richness on ecosystem functioning are enhanced by stronger temperature fluctuations due to the increased performance of individual species. Conclusions Our results provide evidence for the performance enhancing effect and suggest that selection towards functionally dominant species is likely to benefit the maintenance of ecosystem functioning under more variable conditions.

UV Screening in Native and Non-native Plant Species in the Tropical Alpine: Implications for Climate Change-Driven Migration of Species to Higher Elevations

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Paul W. Barnes

2017-08-01

Full Text Available Ongoing changes in Earth’s climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV-B (280–315 nm radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8 and non-native (mean = 5.8%; n = 11 species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees were represented solely by native species whereas herbaceous growth forms (grasses and forbs were dominated by non-native species. Along an elevation gradient spanning 2600–3800 m, TUV A was variable (mean range = 6.0–11.2% and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3% and did not vary with elevation in the native

Ethical and Animal Welfare Considerations in Relation to Species Selection for Animal Experimentation

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John Webster

2014-12-01

Full Text Available Ethical principles governing the conduct of experiments with animals are reviewed, especially those relating to the choice of species. Legislation requires that the potential harm to animals arising from any procedure should be assessed in advance and justified in terms of its possible benefit to society. Potential harms may arise both from the procedures and the quality of the animals’ lifetime experience. The conventional approach to species selection is to use animals with the “lowest degree of neurophysiological sensitivity”. However; this concept should be applied with extreme caution in the light of new knowledge. The capacity to experience pain may be similar in mammals, birds and fish. The capacity to suffer from fear is governed more by sentience than cognitive ability, so it cannot be assumed that rodents or farm animals suffer less than dogs or primates. I suggest that it is unethical to base the choice of species for animal experimentation simply on the basis that it will cause less distress within society. A set of responsibilities is outlined for each category of moral agent. These include regulators, operators directly concerned with the conduct of scientific experiments and toxicology trials, veterinarians and animal care staff; and society at large.

Ethical and Animal Welfare Considerations in Relation to Species Selection for Animal Experimentation.

Science.gov (United States)

Webster, John

2014-12-03

Ethical principles governing the conduct of experiments with animals are reviewed, especially those relating to the choice of species. Legislation requires that the potential harm to animals arising from any procedure should be assessed in advance and justified in terms of its possible benefit to society. Potential harms may arise both from the procedures and the quality of the animals' lifetime experience. The conventional approach to species selection is to use animals with the "lowest degree of neurophysiological sensitivity". However; this concept should be applied with extreme caution in the light of new knowledge. The capacity to experience pain may be similar in mammals, birds and fish. The capacity to suffer from fear is governed more by sentience than cognitive ability, so it cannot be assumed that rodents or farm animals suffer less than dogs or primates. I suggest that it is unethical to base the choice of species for animal experimentation simply on the basis that it will cause less distress within society. A set of responsibilities is outlined for each category of moral agent. These include regulators, operators directly concerned with the conduct of scientific experiments and toxicology trials, veterinarians and animal care staff; and society at large.

Reproductive characterization of interspecific hybrids among Capsicum species

Directory of Open Access Journals (Sweden)

Carlos Eduardo da Silva Monteiro

2011-01-01

Full Text Available The objective of this study was the reproductive characterization of Capsicum accessions as well as of interspecifichybrids, based on pollen viability. Hybrids were obtained between Capsicum species. Pollen viability was high in most accessions,indicating that meiosis is normal, resulting in viable pollen grains. The pollen viability of species C. pubescens was the lowest (27%. The interspecific hybrids had varying degrees of pollen viability, from fertile combinations (C. chinense x C. frutescens and C.annuum x C. baccatum to male sterile combinations. Pollen viability also varied within the hybrid combination according toaccessions used in the cross. Results indicate that male sterility is one of the incompatibility barriers among Capsicum species sincehybrids can be established, but may be male sterile.

Applications, dosimetry and biological interactions of static and time-varying magnetic fields

International Nuclear Information System (INIS)

Tenforde, T.S.

1988-08-01

The primary topics of this presentation include: (1) the applications of magnetic fields in research, industry, and medical technologies; (2) mechanisms of interaction of static and time-varying magnetic fields with living systems; (3) human health effects of exposure to static and time-varying magnetic fields in occupational, medical, and residential settings; and (4) recent advances in the dosimetry of extremely-low-frequency electromagnetic fields. The discussion of these topics is centered about two issues of considerable contemporary interest: (1) potential health effects of the fields used in magnetic resonance imaging and in vivo spectroscopy, and (2) the controversial issue of whether exposure to extremely-low-frequency (ELF) electromagnetic fields in the home and workplace leads to an elevated risk of cancer. 11 refs

Chemical composition and digestibility of some browse plant species collected from Algerian arid rangelands

Energy Technology Data Exchange (ETDEWEB)

Boufennara, S.; Lopez, S.; Boussebouna, H.; Bodas, R.; Bouazza, L.

2012-11-01

Many wild browse and bush species are undervalued mainly because of insufficient knowledge about their potential feeding value. The objective was to evaluate some nutritional attributes of various Algerian browse and shub species (Atriplex halimus, Artemisia campestris, Artemisia herba-alba, Astragalus gombiformis, Calobota saharae, Retama raetam, Stipagrostis pungens, Lygeum spartum and Stipa tenacissima). Chemical composition, phenols and tannins concentration, in vitro digestibility, in vitro gas production kinetics and in vitro bio-assay for assessment of tannins using buffered rumen fluid, and in situ disappearence of the edible parts of the plants (leaves, thin twigs and flowers) were determined. In general, protein content in dicotyledon species was always greater than in monocotyledon grasses, these showing higher neutral and acid detergent fibre and lower lignin contents than dicots. The tannin concentrations varied considerably between species, but in general the plants investigated in this study had low tannin contents (except for Artemisia spp. and S. tenacissima). Monocots showed lower in vitro and in situ digestibilities, fermentation rate, cumulative gas production and extent of degradation than dicot species. The plants were clustered by principal components analysis in two groups: poor-quality grasses and the most digestible dicot species. Chemical composition (neutral detergent fibre and protein) and digestibility were the main influential variables determining the ranking. In conclusion, A. halimus, A. campestris, A. herba-alba and A. gombiformis can be considered of greater nutritional value than the highly fibrous and low digestible grasses (S. pungens, L. spartum and S. tenacissima) that should be considered emergency roughages. (Author) 46 refs.

Leaf gas exchange characteristics of three neotropical mangrove species in response to varying hydroperiod

Science.gov (United States)

Krauss, Ken W.; Twilley, Robert R.; Doyle, Thomas W.; Gardiner, Emile S.

2006-01-01

We determined how different hydroperiods affected leaf gas exchange characteristics of greenhouse-grown seedlings (2002) and saplings (2003) of the mangrove species Avicennia germinans (L.) Stearn., Laguncularia racemosa (L.) Gaertn. f., and Rhizophora mangle L. Hydroperiod treatments included no flooding (unflooded), intermittent flooding (intermittent), and permanent flooding (flooded). Plants in the intermittent treatment were measured under both flooded and drained states and compared separately. In the greenhouse study, plants of all species maintained different leaf areas in the contrasting hydroperiods during both years. Assimilation–light response curves indicated that the different hydroperiods had little effect on leaf gas exchange characteristics in either seedlings or saplings. However, short-term intermittent flooding for between 6 and 22 days caused a 20% reduction in maximum leaf-level carbon assimilation rate, a 51% lower light requirement to attain 50% of maximum assimilation, and a 38% higher demand from dark respiration. Although interspecific differences were evident for nearly all measured parameters in both years, there was little consistency in ranking of the interspecific responses. Species by hydroperiod interactions were significant only for sapling leaf area. In a field study, R. mangle saplings along the Shark River in the Everglades National Park either demonstrated no significant effect or slight enhancement of carbon assimilation and water-use efficiency while flooded. We obtained little evidence that contrasting hydroperiods affect leaf gas exchange characteristics of mangrove seedlings or saplings over long time intervals; however, intermittent flooding may cause short-term depressions in leaf gas exchange. The resilience of mangrove systems to flooding, as demonstrated in the permanently flooded treatments, will likely promote photosynthetic and morphological adjustment to slight hydroperiod shifts in many settings..

Strains of bacterial species induce a greatly varied acute adaptive immune response: The contribution of the accessory genome.

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Uri Sela

2018-01-01

Full Text Available A fundamental question in human susceptibility to bacterial infections is to what extent variability is a function of differences in the pathogen species or in individual humans. To focus on the pathogen species, we compared in the same individual the human adaptive T and B cell immune response to multiple strains of two major human pathogens, Staphylococcus aureus and Streptococcus pyogenes. We found wide variability in the acute adaptive immune response induced by various strains of a species, with a unique combination of activation within the two arms of the adaptive response. Further, this was also accompanied by a dramatic difference in the intensity of the specific protective T helper (Th response. Importantly, the same immune response differences induced by the individual strains were maintained across multiple healthy human donors. A comparison of isogenic phage KO strains, demonstrated that of the pangenome, prophages were the major contributor to inter-strain immune heterogeneity, as the T cell response to the remaining "core genome" was noticeably blunted. Therefore, these findings extend and modify the notion of an adaptive response to a pathogenic bacterium, by implying that the adaptive immune response signature of a bacterial species should be defined either per strain or alternatively to the species' 'core genome', common to all of its strains. Further, our results demonstrate that the acquired immune response variation is as wide among different strains within a single pathogenic species as it is among different humans, and therefore may explain in part the clinical heterogeneity observed in patients infected with the same species.

Acclimation responses to temperature vary with vertical stratification: implications for vulnerability of soil-dwelling species to extreme temperature events.

Science.gov (United States)

van Dooremalen, Coby; Berg, Matty P; Ellers, Jacintha

2013-03-01

The occurrence of summer heat waves is predicted to increase in amplitude and frequency in the near future, but the consequences of such extreme events are largely unknown, especially for belowground organisms. Soil organisms usually exhibit strong vertical stratification, resulting in more frequent exposure to extreme temperatures for surface-dwelling species than for soil-dwelling species. Therefore soil-dwelling species are expected to have poor acclimation responses to cope with temperature changes. We used five species of surface-dwelling and four species of soil-dwelling Collembola that habituate different depths in the soil. We tested for differences in tolerance to extreme temperatures after acclimation to warm and cold conditions. We also tested for differences in acclimation of the underlying physiology by looking at changes in membrane lipid composition. Chill coma recovery time, heat knockdown time and fatty acid profiles were determined after 1 week of acclimation to either 5 or 20 °C. Our results showed that surface-dwelling Collembola better maintained increased heat tolerance across acclimation temperatures, but no such response was found for cold tolerance. Concordantly, four of the five surface-dwelling Collembola showed up to fourfold changes in relative abundance of fatty acids after 1 week of acclimation, whereas none of the soil-dwelling species showed a significant adjustment in fatty acid composition. Strong physiological responses to temperature fluctuations may have become redundant in soil-dwelling species due to the relative thermal stability of their subterranean habitat. Based on the results of the four species studied, we expect that unless soil-dwelling species can temporarily retreat to avoid extreme temperatures, the predicted increase in heat waves under climatic change renders these soil-dwelling species more vulnerable to extinction than species with better physiological capabilities. Being able to act under a larger thermal

Tropical anurans mature early and die young: Evidence from eight Afromontane Hyperolius species and a meta-analysis.

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Ulrich Sinsch

Full Text Available Age- and size-related life-history traits of anuran amphibians are thought to vary systematically with latitude and altitude. Because the available data base is strongly biased towards temperate-zone species, we provide new estimates on eight afrotropical Reed Frog species. A meta-analysis of the demographic traits in 44 tropical anuran species aims to test for the predicted clinal variation and to contrast results with variation detected in temperate-zone species. The small-sized reed frogs reach sexual maturity during the first or second year of life, but longevity does not exceed three to four years. Latitudinal effects on demographic life-history traits are not detectable in tropical anurans, and altitudinal effects are limited to a slight size reduction at higher elevations. Common features of anuran life-history in the tropics are early sexual maturation at small size and low longevity resulting in low lifetime fecundity. This pattern contrasts with that found in temperate-zone anurans which mature later at larger size and grow considerably older yielding greater lifetime fecundity than in the tropics. Latitudinal and altitudinal contraction of the yearly activity period shape the evolution of life-history traits in the temperate region, while trait variation in the tropics seems to be driven by distinct, not yet identified selective forces.

Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species

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Catherine J. Collier

2017-08-01

Full Text Available Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri. To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum (Topt for gross photosynthesis of Z. muelleri, which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The Topt for photosynthesis of the tropical species, H. uninervis and C. serrulata, was considerably higher (35°C on average. This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature (Topt varied by 1°C in C. serrulata and 2°C in H. uninervis, and the variation did not follow changes in ambient water temperature. The Topt for gross photosynthesis were higher than Topt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C and H. uninervis (33°C, but remained unchanged at 35°C in C. serrulata. Both estimated plant net productivity and Topt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The

Analysis on Passivity for Uncertain Neural Networks with Time-Varying Delays

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O. M. Kwon

2014-01-01

Full Text Available The problem of passivity analysis for neural networks with time-varying delays and parameter uncertainties is considered. By the consideration of newly constructed Lyapunov-Krasovskii functionals, improved sufficient conditions to guarantee the passivity of the concerned networks are proposed with the framework of linear matrix inequalities (LMIs, which can be solved easily by various efficient convex optimization algorithms. The enhancement of the feasible region of the proposed criteria is shown via two numerical examples by the comparison of maximum allowable delay bounds.

Species conservation and natural variation among populations [Chapter 5

Science.gov (United States)

Leonard F. Ruggiero; Michael K. Schwartz; Keith B. Aubry; Charles J. Krebs; Amanda Stanley; Steven W. Buskirk

2000-01-01

In conservation planning, the importance of natural variation is often given inadequate consideration. However, ignoring the implications of variation within species may result in conservation strategies that jeopardize, rather than conserve, target species (see Grieg 1979; Turcek 1951; Storfer 1999). Natural variation in the traits of individuals and populations is...

76 FR 34746 - Species Proposals for Consideration at the Sixteenth Regular Meeting of the Conference of the...

Science.gov (United States)

2011-06-14

... recommendations on animal and plant species that should be considered as candidates for U.S. proposals to amend... to regulate international trade in certain animal and plant species that are now, or potentially may become, threatened with extinction. These species are listed in the Appendices to CITES, which are...

Fatty Acid Compositions of Six Wild Edible Mushroom Species

Science.gov (United States)

Günç Ergönül, Pelin; Akata, Ilgaz; Kalyoncu, Fatih; Ergönül, Bülent

2013-01-01

The fatty acids of six wild edible mushroom species (Boletus reticulatus, Flammulina velutipes var. velutipes, Lactarius salmonicolor, Pleurotus ostreatus, Polyporus squamosus, and Russula anthracina) collected from different regions from Anatolia were determined. The fatty acids were identified and quantified by gas chromatography and studied using fruit bodies. Fatty acid composition varied among species. The dominant fatty acid in fruit bodies of all mushrooms was cis-linoleic acid (18 : 2). Percentage of cis-linoleic acid in species varied from 22.39% to 65.29%. The other major fatty acids were, respectively, cis-oleic, palmitic, and stearic acids. Fatty acids analysis of the mushrooms showed that the unsaturated fatty acids were at higher concentrations than saturated fatty acids. PMID:23844377

Fatty Acid Compositions of Six Wild Edible Mushroom Species

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Pelin Günç Ergönül

2013-01-01

Full Text Available The fatty acids of six wild edible mushroom species (Boletus reticulatus, Flammulina velutipes var. velutipes, Lactarius salmonicolor, Pleurotus ostreatus, Polyporus squamosus, and Russula anthracina collected from different regions from Anatolia were determined. The fatty acids were identified and quantified by gas chromatography and studied using fruit bodies. Fatty acid composition varied among species. The dominant fatty acid in fruit bodies of all mushrooms was cis-linoleic acid (18 : 2. Percentage of cis-linoleic acid in species varied from 22.39% to 65.29%. The other major fatty acids were, respectively, cis-oleic, palmitic, and stearic acids. Fatty acids analysis of the mushrooms showed that the unsaturated fatty acids were at higher concentrations than saturated fatty acids.

Genetic factors affecting sexual reproduction in toxigenic Fusarium species

NARCIS (Netherlands)

Hornok, L.; Waalwijk, C.; Leslie, J.F.

2007-01-01

Mycotoxin producing capability greatly varies within species. In theory, the major source of this variability is meiotic recombination. However, a number of important toxigenic species have no known sexual stage and, therefore, the origin of the intraspecific diversity in these fungi is poorly

Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

Science.gov (United States)

Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

2003-01-01

The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

Enantioselective Separation of 4,8-DHT and Phytotoxicity of the Enantiomers on Various Plant Species.

Science.gov (United States)

Yang, Li; Ma, Xiao-Yan; Ruan, Xiao; Jiang, De-An; Pan, Cun-De; Wang, Qiang

2016-04-22

As a candidate for bioherbicide, 4,8-dihydroxy-1-tetralone (4,8-DHT) was isolated from Caryospora callicarpa epicarp and its two enantiomers, S-(+)-isosclerone and R-(-)-regiolone, were separated by chiral high-performance liquid chromatography (HPLC) on a Chiralcel OD column with chiral stationary phase (CSP)-coated cellulose-tris(3,5-dimethylphenylcarbamate). Then, the phytotoxicity of 4,8-DHT and its enantiomers toward the seeds germination and seedling growth of the five tested plant species, including lettuce (Latuca sativa), radish (Raphanus sativus), cucumber (Cucumis sativus), onion (Allium cepa), and wheat (Triticum aestivum), were investigated and the results indicated a hormesis at low concentration of 4,8-DHT and its enantiomers, but a retardant effect at high concentration. Between the two enantiomers of 4,8-DHT, the S-(+)-isosclerone was more toxic to seeds germination and seedling growth of the five tested plant species than the R-(-)-regiolone, and also the phytotoxicity of S-(+)-isosclerone varied with different plants. For example, S-(+)-isosclerone was the most active to seedling growth of lettuce, indicating that S-(+)-isosclerone had specific effects on different organisms. Thus, all of the chirality and concentration of 4,8-DHT, as well as the affected plant species, need to be taken into consideration in the development and utilization of 4,8-DHT.

An Ethnobotanical Survey on Fuel Wood and Timber plant Species ...

African Journals Online (AJOL)

Yomi

2011-12-19

Dec 19, 2011 ... 3Department of Botany, Post Graduate College Abbottabad, Pakistan. Accepted 17 March, 2011. A survey was conducted to explore the fuel wood species and timber producing species of Kaghan valleys, Pakistan. Consumption pattern and impact on the forest resources were also taken into consideration.

Do varying aquatic plant species affect phytoplankton and crustacean responses to a nitrogen-permethrin mixture?

Science.gov (United States)

Hydraulically connected wetland microcosms vegetated with either Typha latifolia or Myriophyllum aquaticum were amended with an NH4NO3 and permethrin mixture to assess the effectiveness of both plant species in mitigating ecological effects of the pollutant mixture on phytoplankton (as chlorophyll a...

Non-random species loss in bacterial communities reduces antifungal volatile production

NARCIS (Netherlands)

Hol, G.; Garbeva, P.; Hordijk, C.; Hundscheid, M.P.J.; Klein Gunnewiek, P.J.A.; Agtmaal, van M.; Boer, de W.

2015-01-01

The contribution of low-abundance microbial species to soil ecosystems is easily overlooked because there is considerable overlap between metabolic abilities (functional redundancy) of dominant and subordinate microbial species. Here we studied how loss of less abundant soil bacteria affected the

New chloroplast microsatellite markers suitable for assessing genetic diversity of Lolium perenne and other related grass species.

Science.gov (United States)

Diekmann, Kerstin; Hodkinson, Trevor R; Barth, Susanne

2012-11-01

Lolium perenne (perennial ryegrass) is the most important forage grass species of temperate regions. We have previously released the chloroplast genome sequence of L. perenne 'Cashel'. Here nine chloroplast microsatellite markers are published, which were designed based on knowledge about genetically variable regions within the L. perenne chloroplast genome. These markers were successfully used for characterizing the genetic diversity in Lolium and different grass species. Chloroplast genomes of 14 Poaceae taxa were screened for mononucleotide microsatellite repeat regions and primers designed for their amplification from nine loci. The potential of these markers to assess genetic diversity was evaluated on a set of 16 Irish and 15 European L. perenne ecotypes, nine L. perenne cultivars, other Lolium taxa and other grass species. All analysed Poaceae chloroplast genomes contained more than 200 mononucleotide repeats (chloroplast simple sequence repeats, cpSSRs) of at least 7 bp in length, concentrated mainly in the large single copy region of the genome. Nucleotide composition varied considerably among subfamilies (with Pooideae biased towards poly A repeats). The nine new markers distinguish L. perenne from all non-Lolium taxa. TeaCpSSR28 was able to distinguish between all Lolium species and Lolium multiflorum due to an elongation of an A(8) mononucleotide repeat in L. multiflorum. TeaCpSSR31 detected a considerable degree of microsatellite length variation and single nucleotide polymorphism. TeaCpSSR27 revealed variation within some L. perenne accessions due to a 44-bp indel and was hence readily detected by simple agarose gel electrophoresis. Smaller insertion/deletion events or single nucleotide polymorphisms detected by these new markers could be visualized by polyacrylamide gel electrophoresis or DNA sequencing, respectively. The new markers are a valuable tool for plant breeding companies, seed testing agencies and the wider scientific community due to

Pseudomonas putida and Pseudomonas fluorescens Species Group Recovery from Human Homes Varies Seasonally and by Environment.

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Susanna K Remold

Full Text Available By shedding light on variation in time as well as in space, long-term biogeographic studies can help us define organisms' distribution patterns and understand their underlying drivers. Here we examine distributions of Pseudomonas in and around 15 human homes, focusing on the P. putida and P. fluorescens species groups. We describe recovery from 10,941 samples collected during up to 8 visits per home, occurring on average 2.6 times per year. We collected a mean of 141 samples per visit, from sites in most rooms of the house, from the surrounding yards, and from human and pet occupants. We recovered Pseudomonas in 9.7% of samples, with the majority of isolates being from the P. putida and P. fluorescens species groups (approximately 62% and 23% of Pseudomonas samples recovered respectively. Although representatives of both groups were recovered from every season, every house, and every type of environment sampled, recovery was highly variable across houses and samplings. Whereas recovery of P. putida group was higher in summer and fall than in winter and spring, P. fluorescens group isolates were most often recovered in spring. P. putida group recovery from soils was substantially higher than its recovery from all other environment types, while higher P. fluorescens group recovery from soils than from other sites was much less pronounced. Both species groups were recovered from skin and upper respiratory tract samples from healthy humans and pets, although this occurred infrequently. This study indicates that even species that are able to survive under a broad range of conditions can be rare and variable in their distributions in space and in time. For such groups, determining patterns and causes of stochastic and seasonal variability may be more important for understanding the processes driving their biogeography than the identity of the types of environments in which they can be found.

Macromorphological and micromorphological studies of four selected passiflora species in peninsular malaysia

International Nuclear Information System (INIS)

Veeramohan, R.; Haron, N.W.

2015-01-01

Taxonomic studies of four selected Passiflora species; Passiflora edulis Sims (Passion fruit), Passiflora coccinea Aubl. (Scarlet passion flower), Passiflora foetida L. (Stinking passion flower) and Passiflora incarnata L. (Fragrant passion flower) were carried out to distinguish their morphological characteristics. Macromorphological characters on the leaves, flowers and fruits of all four Passiflora species were observed under a binocular microscope and they varied characteristically in terms of colour, texture and shape of flowers, leaves and fruits. Jeol JSM-7500F Scanning Electron Microscope was used to observe the micromorphological characters such as stomata, trichomes, and leaf surface indumentum of each Passiflora species. Micromorphologically, each species varied in types and sizes of stomata, epidermal. (author)

Do parasitic trematode cercariae demonstrate a preference for susceptible host species?

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Brittany F Sears

Full Text Available Many parasites are motile and exhibit behavioural preferences for certain host species. Because hosts can vary in their susceptibility to infections, parasites might benefit from preferentially detecting and infecting the most susceptible host, but this mechanistic hypothesis for host-choice has rarely been tested. We evaluated whether cercariae (larval trematode parasites prefer the most susceptible host species by simultaneously presenting cercariae with four species of tadpole hosts. Cercariae consistently preferred hosts in the following order: Anaxyrus ( = Bufo terrestris (southern toad, Hyla squirella (squirrel tree frog, Lithobates ( = Rana sphenocephala (southern leopard frog, and Osteopilus septentrionalis (Cuban tree frog. These host species varied in susceptibility to cercariae in an order similar to their attractiveness with a correlation that approached significance. Host attractiveness to parasites also varied consistently and significantly among individuals within a host species. If heritable, this individual-level host variation would represent the raw material upon which selection could act, which could promote a Red Queen "arms race" between host cues and parasite detection of those cues. If, in general, motile parasites prefer to infect the most susceptible host species, this phenomenon could explain aggregated distributions of parasites among hosts and contribute to parasite transmission rates and the evolution of virulence. Parasite preferences for hosts belie the common assumption of disease models that parasites seek and infect hosts at random.

Early establishment of trees at the alpine treeline: idiosyncratic species responses to temperature-moisture interactions.

Science.gov (United States)

Loranger, Hannah; Zotz, Gerhard; Bader, Maaike Y

2016-01-01

On a global scale, temperature is the main determinant of arctic and alpine treeline position. However on a local scale, treeline form and position vary considerably due to other climatic factors, tree species ecology and life-stage-dependent responses. For treelines to advance poleward or uphill, the first steps are germination and seedling establishment. These earliest life stages may be major bottlenecks for treeline tree populations and will depend differently on climatic conditions than adult trees. We investigated the effect of soil temperature and moisture on germination and early seedling survival in a field experiment in the French Alps near the local treeline (2100 m a.s.l.) using passive temperature manipulations and two watering regimes. Five European treeline tree species were studied: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata and Sorbus aucuparia In addition, we monitored the germination response of three of these species to low temperatures under controlled conditions in growth chambers. The early establishment of these trees at the alpine treeline was limited either by temperature or by moisture, the sensitivity to one factor often depending on the intensity of the other. The results showed that the relative importance of the two factors and the direction of the effects are highly species-specific, while both factors tend to have consistent effects on both germination and early seedling survival within each species. We show that temperature and water availability are both important contributors to establishment patterns of treeline trees and hence to species-specific forms and positions of alpine treelines. The observed idiosyncratic species responses highlight the need for studies including several species and life-stages to create predictive power concerning future treeline dynamics. © The Authors 2016. Published by Oxford University Press on behalf of the Annals of Botany Company.

Phenology of selected herbaceous species of northern Wisconsin deciduous forests and forest roads

International Nuclear Information System (INIS)

Zavitkovski, J.

1977-01-01

Vegetative and reproductive phenophases were observed from 1970 to 1974 on 30 native and 8 introduced herbaceous species growing under deciduous forests and on an abandoned logging road in the Enterprise Radiation Forest in northern Wisconsin. Forest herbs started growing in the same order each year, but logging-road herbs varied. Growth initiation was more variable in the early-starting than in the late-starting species. In most years logging-road herbs started growth a few days earlier than forest herbs. Initiation of flowering of the 38 species was bimodal, culminating around mid-May for forest species and around mid-July for logging-road species. In general, the annual start of flowering varied less than the start of vegetative growth. Duration of flowering of most species was variable, however. Seed ripening times varied strikingly among species, ranging from 11 days for Taraxacum officinale to 101 days for Iris versicolor. Seeds of forest herbs took longer to ripen than those of logging-road species. On the basis of growth initiation of the 6 earliest species, spring arrival in 1970 to 1974 differed by 26 days and appeared to be related to snow disappearance. The growing season of most species paralleled cumulative current-year (May--July) and last-year (August--September) precipitation. Multiple regression analyses between precipitation and average length of growing season explained 87 percent of the total variation for forest herbs and 69 percent of that for logging-road herbs

Endogenous time-varying risk aversion and asset returns.

Science.gov (United States)

Berardi, Michele

2016-01-01

Stylized facts about statistical properties for short horizon returns in financial markets have been identified in the literature, but a satisfactory understanding for their manifestation is yet to be achieved. In this work, we show that a simple asset pricing model with representative agent is able to generate time series of returns that replicate such stylized facts if the risk aversion coefficient is allowed to change endogenously over time in response to unexpected excess returns under evolutionary forces. The same model, under constant risk aversion, would instead generate returns that are essentially Gaussian. We conclude that an endogenous time-varying risk aversion represents a very parsimonious way to make the model match real data on key statistical properties, and therefore deserves careful consideration from economists and practitioners alike.

An Ethnobotanical Survey on Fuel Wood and Timber plant Species ...

African Journals Online (AJOL)

A survey was conducted to explore the fuel wood species and timber producing species of Kaghan valleys, Pakistan. Consumption pattern and impact on the forest resources were also taken into consideration. A questionnaire was used as a survey instrument to obtain desired data. For this study, 10 villages were randomly ...

Determining species expansion and extinction possibilities using probabilistic and graphical models

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Chaturvedi Rajesh

2015-03-01

Full Text Available Survival of plant species is governed by a number of functions. The participation of each function in species survival and the impact of the contrary behaviour of the species vary from function to function. The probability of extinction of species varies in all such scenarios and has to be calculated separately. Secondly, species follow different patterns of dispersal and localisation at different stages of occupancy state of the site, therefore, the scenarios of competition for resources with climatic shifts leading to deterioration and loss of biodiversity resulting in extinction needs to be studied. Furthermore, most possible deviations of species from climax community states needs to be calculated before species become extinct due to sudden environmental disruption. Globally, various types of anthropogenic disturbances threaten the diversity of biological systems. The impact of these anthropogenic activities needs to be analysed to identify extinction patterns with respect to these activities. All the analyses mentioned above have been tried to be achieved through probabilistic or graphical models in this study.

Methylation of inorganic arsenic in different mammalian species and population groups.

Science.gov (United States)

Vahter, M

1999-01-01

Thousands of people in different parts of the world are exposed to arsenic via drinking water or contaminated soil or food. The high general toxic of arsenic has been known for centuries, and research during the last decades has shown that arsenic is a potent human carcinogen. However, most experimental cancer studies have failed to demonstrate carcinogenicity in experimental animals, indicating marked variation in sensitivity towards arsenic toxicity between species. It has also been suggested that there is a variation in susceptibility among human individuals. One reason for such variability in toxic response may be variation in metabolism. Inorganic arsenic is methylated in humans as well as animals and micro-organisms, but there are considerable differences between species and individuals. In many, but not all, mammalian species, inorganic arsenic is methylated to methylarsonic acid (MMA) and dimethylarsinic acid (DMA), which are more rapidly excreted in urine than is the inorganic arsenic, especially the trivalent form (AsIII, arsenite) which is highly reactive with tissue components. Absorbed arsenate (AsV) is reduced to trivalent arsenic (AsIII) before the methyl groups are attached. It has been estimated that as much as 50-70% of absorbed AsV is rapidly reduced to AsIII, a reaction which seems to be common for most species. In most experimental animal species, DMA is the main metabolite excreted in urine. Compared to human subjects, very little MMA is produced. However, the rate of methylation varies considerably between species, and several species, e.g. the marmoset monkey and the chimpanzee have been shown not to methylate inorganic arsenic at all. In addition, the marmoset monkey accumulates arsenic in the liver. The rat, on the other hand, has an efficient methylation of arsenic but the formed DMA is to a large extent accumulated in the red blood cells. As a result, the rat shows a low rate of excretion of arsenic. In both human subjects and rodents

Toxicity of pentachlorophenol to aquatic organisms under naturally varying and controlled environmental conditions

Energy Technology Data Exchange (ETDEWEB)

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

1986-06-01

The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty-one acute toxicity tests were conducted, with LC50 values ranging from 85 micrograms/L for the white sucker Catastomus commersoni during the summer to greater than 7770 micrograms/L for the isopod Asellus racovitzai during the winter. The effect of PCP on growth and/or reproduction was determined for seven species. The most sensitive chronically exposed organisms were the cladoceran Ceriodaphnia reticulata and the snail Physa gyrina. The greatest variation in toxicity was due to species sensitivity. Within a given, season there was as much as a 40-fold difference in LC50 values between species. For any one species, the maximum variation in LC50 between seasons was approximately 14-fold. There were also substantial differences in acute-chronic relationships, with acute/chronic ratios ranging from greater than 37 for C. reticulata to 1 for Simocephalus vetulus. It is suggested that the composition of the aquatic community should be the most important consideration in estimating the potential environmental effects of PCP.

Pollinator effectiveness varies with experimental shifts in flowering time.

Science.gov (United States)

Rafferty, Nicole E; Ives, Anthony R

2012-04-01

The earlier flowering times exhibited by many plant species are a conspicuous sign of climate change. Altered phenologies have caused concern that species could suffer population declines if they flower at times when effective pollinators are unavailable. For two perennial wildflowers, Tradescantia ohiensis and Asclepias incarnata, we used an experimental approach to explore how changing phenology affects the taxonomic composition of the pollinator assemblage and the effectiveness of individual pollinator taxa. After finding in the previous year that fruit set varied with flowering time, we manipulated flowering onset in greenhouses, placed plants in the field over the span of five weeks, and measured pollinator effectiveness as the number of seeds produced after a single visit to a flower. The average effectiveness of pollinators and the expected rates of pollination success were lower for plants of both species flowering earlier than for plants flowering at historical times, suggesting there could be reproductive costs to earlier flowering. Whereas for A. incarnata, differences in average seed set among weeks were due primarily to changes in the composition of the pollinator assemblage, the differences for T. ohiensis were driven by the combined effects of compositional changes and increases over time in the effectiveness of some pollinator taxa. Both species face the possibility of temporal mismatch between the availability of the most effective pollinators and the onset of flowering, and changes in the effectiveness of individual pollinator taxa through time may add an unexpected element to the reproductive consequences of such mismatches.

Inhibitory effects of antimicrobial agents against Fusarium species.

Science.gov (United States)

Kawakami, Hideaki; Inuzuka, Hiroko; Hori, Nobuhide; Takahashi, Nobumichi; Ishida, Kyoko; Mochizuki, Kiyofumi; Ohkusu, Kiyofumi; Muraosa, Yasunori; Watanabe, Akira; Kamei, Katsuhiko

2015-08-01

We investigated the inhibitory effects of antibacterial, biocidal, and antifungal agents against Fusarium spp. Seven Fusarium spp: four F. falciforme (Fusarium solani species complex), one Fusarium spp, one Fusarium spp. (Fusarium incarnatum-equiseti species complex), and one F. napiforme (Gibberella fujikuroi species complex), isolated from eyes with fungal keratitis were used in this study. Their susceptibility to antibacterial agents: flomoxef, imipenem, gatifloxacin, levofloxacin, moxifloxacin, gentamicin, tobramycin, and Tobracin® (contained 3,000 μg/ml of tobramycin and 25 μg/ml of benzalkonium chloride (BAK), a biocidal agent: BAK, and antifungal agents: amphotericin B, pimaricin (natamycin), fluconazole, itraconazole, miconazole, voriconazole, and micafungin, was determined by broth microdilution tests. The half-maximal inhibitory concentration (IC50), 100% inhibitory concentration (IC100), and minimum inhibitory concentration (MIC) against the Fusarium isolates were determined. BAK had the highest activity against the Fusarium spp. except for the antifungal agents. Three fluoroquinolones and two aminoglycosides had inhibitory effects against the Fusarium spp. at relatively high concentrations. Tobracin® had a higher inhibitory effect against Fusarium spp. than tobramycin alone. Amphotericin B had the highest inhibitory effect against the Fusarium spp, although it had different degrees of activity against each isolate. Our findings showed that fluoroquinolones, aminoglycosides, and BAK had some degree of inhibitory effect against the seven Fusarium isolates, although these agents had considerably lower effect than amphotericin B. However, the inhibitory effects of amphotericin B against the Fusarium spp. varied for the different isolates. Further studies for more effective medications against Fusarium, such as different combinations of antibacterial, biocidal, and antifungal agents are needed. © The Author 2015. Published by Oxford University Press on

Landscape forest cover and edge effects on songbird nest predation vary by nest predator

Science.gov (United States)

W. Andrew Cox; Frank R. III Thompson; John. Faaborg

2012-01-01

Rates of nest predation for birds vary between and within species across multiple spatial scales, but we have a poor understanding of which predators drive such patterns. We video-monitored nests and identified predators at 120 nests of the Acadian Flycatcher (Empidonax virescens) and the Indigo Bunting (Passerina cyanea) at eight...

[Regenerative morphological traits in a woody species community in Tumbesian tropical dry forest].

Science.gov (United States)

Romero-Saritama, José Miguel; Pérez-Rúuz, César

2016-06-01

The study of functional morphological traits enables us to know fundamental aspects of the dynamics of plant communities in local and global habitats. Regenerative morphological traits play an important role in defining plant history and ecological behavior. Seed and fruit characteristics determine to a large extent the patterns for dispersal, germination, establishment and seedling recruitment a given species exhibits on its natural habitat. Despite their prominent role, seed and fruit traits have been poorly studied at the community level of woody plant species in neo-tropical dry forests. In the present study we aimed at i) evaluate the functional role of morphological traits of seeds, fruits and embryo in woody plant species; ii) determine which are the morphological patterns present in seeds collected from the community of woody species that occur in neo-tropical dry forests; and iii) compare woody plant species seed mass values comparatively between neo-tropical dry and tropical forests. To do so, mature seeds were collected from 79 plant species that occur in the Tumbesian forest of Southwest Ecuador. The studied species included the 42 and 37 most representative tree and shrubbery species of the Tumbesian forest respectively. A total of 18 morphological traits (seven quantitative and 11 qualitative) were measured and evaluated in the seeds, fruits and embryos of the selected species, and we compared the seeds mass with other forest types. Our results showed a huge heterogeneity among traits values in the studied species. Seed mass, volume and number were the traits that vary the most at the community level, i.e. seed length ranged from 1.3 to 39 mm, and seed width from 0.6 to 25 mm. Only six embryo types were found among the 79 plant species. In 40 % of the cases, fully developed inverted embryos with large and thick cotyledons to store considerable amount of nutrients were recorded. We concluded that highly variable and functionally complementary

Breeding sites and species association of the main Bluetongue and Schmallenberg virus vectors, the Culicoides species (Diptera: Ceratopogonidae), in northern Europe

OpenAIRE

Zimmer, Jean-Yves; Losson, Bertrand; Saegerman, Claude; Haubruge, Eric; Francis, Frédéric

2013-01-01

Several species of Culicoides (Diptera: Ceratopogonidae) biting midges are biological vectors of bluetongue virus (BTV) and, as recently discovered, Schmallenberg virus (SBV) in northern Europe. Since their recent emergence in this part of the continent, these diseases that affect domestic and wild ruminants have caused considerable economic losses to the sheep and cattle industries. The substrates that are suitable for larval development of the main vector species are still relatively unknow...

Deriving field-based species sensitivity distributions (f-SSDs) from stacked species distribution models (S-SDMs).

Science.gov (United States)

Schipper, Aafke M; Posthuma, Leo; de Zwart, Dick; Huijbregts, Mark A J

2014-12-16

Quantitative relationships between species richness and single environmental factors, also called species sensitivity distributions (SSDs), are helpful to understand and predict biodiversity patterns, identify environmental management options and set environmental quality standards. However, species richness is typically dependent on a variety of environmental factors, implying that it is not straightforward to quantify SSDs from field monitoring data. Here, we present a novel and flexible approach to solve this, based on the method of stacked species distribution modeling. First, a species distribution model (SDM) is established for each species, describing its probability of occurrence in relation to multiple environmental factors. Next, the predictions of the SDMs are stacked along the gradient of each environmental factor with the remaining environmental factors at fixed levels. By varying those fixed levels, our approach can be used to investigate how field-based SSDs for a given environmental factor change in relation to changing confounding influences, including for example optimal, typical, or extreme environmental conditions. This provides an asset in the evaluation of potential management measures to reach good ecological status.

Nest-niche differentiation in two sympatric columbid species from a Mediterranean Tetraclinis woodland: Considerations for forest management

Science.gov (United States)

Hanane, Saâd; Yassin, Mohamed

2017-01-01

Studies of niche partitioning among Columbid species have mainly addressed food habits and foraging activities, while partitioning in relation to nest-niche differentiation has been little studied. Here we investigate whether two sympatric columbid species-Woodpigeon (Columba palumbus) and Turtle dove (Streptopelia turtur)-occupy similar niches. A total of 74 nests were monitored: 37 nests for each species. The study, conducted in June 2016, attempted to determine the factors that may play a role in nest-niche differentiation among the two sympatric columbid species in a Moroccan Thuya (Tetraclinis articulata) forest. We used Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) to test the relevance of nest placement, proximity of food resources, forest edge and human presence variables in the nest distribution of the two species. The results show substantial niche segregation in the T. articulata nest-trees selected by Woodpigeons and Turtle doves, with selection depending primarily on the tree size and nest height. Observed nest-niche partitioning may diminish the potential for competition between these species and enhance opportunities for their coexistence. Management policies and practices aimed at ensuring the presence of mixed-sized class of Thuya trees must be prioritized. We recommend additional studies designed to: (1) reproduce the same experimental approach on other Mediterranean Thuya forests to improve our understanding of the effects of different levels of anthropogenic disturbance on the breeding behaviour of these two game species; (2) better understand the spatio-temporal dynamics of Woodpigeon and Turtle dove coexistence in the region; and (3) better identify the spatio-temporal extent of the effect of forest management on Woodpigeon and Turtle dove site occupancy.

Alcohol in Moderation, Cardioprotection and Neuroprotection: Epidemiological Considerations and Mechanistic Studies

OpenAIRE

Collins, Michael A.; Neafsey, Edward J.; Mukamal, Kenneth J.; Gray, Mary O.; Parks, Dale A.; Das, Dipak K.; Korthuis, Ronald J.

2008-01-01

In contrast to many years of important research and clinical attention to the pathological effects of alcohol (ethanol) abuse, the past several decades have seen the publication of a number of peer-reviewed studies indicating beneficial effects of light-moderate, non-binge consumption of varied alcoholic beverages, as well as experimental demonstrations that moderate alcohol exposure can initiate typically cytoprotective mechanisms. A considerable body of epidemiology associates moderate alco...

On the myths of indicator species: issues and further consideration in the use of static concepts for ecological applications.

Directory of Open Access Journals (Sweden)

Michael L Zettler

Full Text Available The use of static indicator species, in which species are expected to have a similar sensitivity or tolerance to either natural or human-induced stressors, does not account for possible shifts in tolerance along natural environmental gradients and between biogeographic regions. Their indicative value may therefore be considered at least questionable. In this paper we demonstrate how species responses (i.e. abundance to changes in sediment grain size and organic matter (OM alter along a salinity gradient and conclude with a plea for prudency when interpreting static indicator-based quality indices. Six model species (three polychaetes, one amphipod and two bivalves from the North Sea, Baltic Sea and the Mediterranean Sea region were selected. Our study demonstrated that there were no generic relationships between environment and biota and half of the studied species showed different responses in different seas. Consequently, the following points have to be carefully considered when applying static indicator-based quality indices: (1 species tolerances and preferences may change along environmental gradients and between different biogeographic regions, (2 as environment modifies species autecology, there is a need to adjust indicator species lists along major environmental gradients and (3 there is a risk of including sibling or cryptic species in calculating the index value of a species.

intra-species variation of the properties of gum exudates from Acacia

African Journals Online (AJOL)

a

The results show that significant inter-species variation of the properties of the gum exudates from the two species exist, whereas only some parameters show significant intra-species variation. The specific optical rotations of the gum exudates have been found to vary from ---43.2o to ---52o for Acacia senegal var. senegal ...

The effect of juvenile hormone on Polistes wasp fertility varies with cooperative behavior.

Science.gov (United States)

Tibbetts, Elizabeth A; Sheehan, Michael J

2012-04-01

Social insects provide good models for studying how and why the mechanisms that underlie reproduction vary, as there is dramatic reproductive plasticity within and between species. Here, we test how the effect of juvenile hormone (JH) on fertility covaries with cooperative behavior in workers and nest-founding queens in the primitively eusocial wasp Polistes metricus. P. metricus foundresses and workers appear morphologically similar and both are capable of reproduction, though there is variation in the extent of social cooperation and the probability of reproduction across castes. Do the endocrine mechanisms that mediate reproduction co-vary with cooperative behavior? We found dramatic differences in the effect of JH on fertility across castes. In non-cooperative nest-founding queens, all individuals responded to JH by increasing their fertility. However, in cooperative workers, the effect of JH on fertility varies with body weight; large workers increase their fertility in response to JH while small workers do not. The variation in JH response may be an adaptation to facilitate resource allocation based on the probability of independent reproduction. This work contrasts with previous studies in closely related Polistes dominulus paper wasps, in which both foundresses and workers form cooperative associations and both castes show similar, condition-dependent JH response. The variation in JH responsiveness within and between species suggests that endocrine responsiveness and the factors influencing caste differentiation are surprisingly evolutionarily labile. Copyright © 2012 Elsevier Inc. All rights reserved.

Phytochemistry and Pharmacology of Berberis Species

Science.gov (United States)

Mokhber-Dezfuli, Najmeh; Saeidnia, Soodabeh; Gohari, Ahmad Reza; Kurepaz-Mahmoodabadi, Mahdieh

2014-01-01

The genus Berberis (Berberidaceae) includes about 500 species worldwide, some of which are widely cultivated in the north-eastern regions of Iran. This genus consists of spiny deciduous evergreen shrubs, characterized by yellow wood and flowers. The cultivation of seedless barberry in South Khorasan goes back to two hundred years ago. Medicinal properties for all parts of these plants have been reported, including: Antimicrobial, antiemetic, antipyretic, antioxidant, anti-inflammatory, anti-arrhythmic, sedative, anti-cholinergic, cholagogic, anti-leishmaniasis, and anti-malaria. The main compounds found in various species of Berberis, are berberine and berbamine. Phytochemical analysis of various species of this genus revealed the presence of alkaloids, tannins, phenolic compounds, sterols and triterpenes. Although there are some review articles on Berberis vulgaris (as the most applied species), there is no review on the phytochemical and pharmacological activities of other well-known species of the genus Berberis. For this reason, the present review mainly focused on the diverse secondary metabolites of various species of this genus and the considerable pharmacological and biological activities together with a concise story of the botany and cultivation. PMID:24600191

Average niche breadths of species in lake macrophyte communities respond to ecological gradients variably in four regions on two continents.

Science.gov (United States)

Alahuhta, Janne; Virtala, Antti; Hjort, Jan; Ecke, Frauke; Johnson, Lucinda B; Sass, Laura; Heino, Jani

2017-05-01

Different species' niche breadths in relation to ecological gradients are infrequently examined within the same study and, moreover, species niche breadths have rarely been averaged to account for variation in entire ecological communities. We investigated how average environmental niche breadths (climate, water quality and climate-water quality niches) in aquatic macrophyte communities are related to ecological gradients (latitude, longitude, altitude, species richness and lake area) among four distinct regions (Finland, Sweden and US states of Minnesota and Wisconsin) on two continents. We found that correlations between the three different measures of average niche breadths and ecological gradients varied considerably among the study regions, with average climate and average water quality niche breadth models often showing opposite trends. However, consistent patterns were also found, such as widening of average climate niche breadths and narrowing of average water quality niche breadths of aquatic macrophytes along increasing latitudinal and altitudinal gradients. This result suggests that macrophyte species are generalists in relation to temperature variations at higher latitudes and altitudes, whereas species in southern, lowland lakes are more specialised. In contrast, aquatic macrophytes growing in more southern nutrient-rich lakes were generalists in relation to water quality, while specialist species are adapted to low-productivity conditions and are found in highland lakes. Our results emphasise that species niche breadths should not be studied using only coarse-scale data of species distributions and corresponding environmental conditions, but that investigations on different kinds of niche breadths (e.g., climate vs. local niches) also require finer resolution data at broad spatial extents.

Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species.

Science.gov (United States)

Collier, Catherine J; Ow, Yan X; Langlois, Lucas; Uthicke, Sven; Johansson, Charlotte L; O'Brien, Katherine R; Hrebien, Victoria; Adams, Matthew P

2017-01-01

Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km) in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant) occurs, for three seagrass species ( Cymodocea serrulata, Halodule uninervis , and Zostera muelleri ). To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum ( T opt ) for gross photosynthesis of Z. muelleri , which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The T opt for photosynthesis of the tropical species, H. uninervis and C. serrulata , was considerably higher (35°C on average). This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature ( T opt varied by 1°C in C. serrulata and 2°C in H. uninervis , and the variation did not follow changes in ambient water temperature). The T opt for gross photosynthesis were higher than T opt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C) and H. uninervis ( 33°C), but remained unchanged at 35°C in C. serrulata . Both estimated plant net productivity and T opt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The

Oral bioaccessibility of toxic and essential elements in raw and cooked commercial seafood species available in European markets

NARCIS (Netherlands)

Alves, Ricardo N.; Maulvault, Ana L.; Barbosa, Vera L.; Fernandez-Tejedor, Margarita; Tediosi, Alice; Kotterman, Michiel; Heuvel, van den Fredericus H.M.; Robbens, Johan; Fernandes, José O.; Romme Rasmussen, Rie; Sloth, Jens J.; Marques, António

2017-01-01

The oral bioaccessibility of several essential and toxic elements was investigated in raw and cooked commercially available seafood species from European markets. Bioaccessibility varied between seafood species and elements. Methylmercury bioaccessibility varied between 10 (octopus) and 60%

Adaptation of C4 Bioenergy Crop Species to Various Environments within the Southern Great Plains of USA

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Sumin Kim

2017-01-01

Full Text Available As highly productive perennial grasses are evaluated as bioenergy feedstocks, a major consideration is biomass yield stability. Two experiments were conducted to examine some aspects of yield stability for two biofuel species: switchgrass (Panicum vigratum L. and Miscanthus x giganteus (Mxg. Biomass yields of these species were evaluated under various environmental conditions across the Southern Great Plains (SGP, including some sites with low soil fertility. In the first experiment, measured yields of four switchgrass ecotypes and Mxg varied among locations. Overall, plants showed optimal growth performance in study sites close to their geographical origins. Lowland switchgrass ecotypes and Mxg yields simulated by the ALMANAC model showed reasonable agreement with the measured yields across all study locations, while the simulated yields of upland switchgrass ecotypes were overestimated in northern locations. In the second experiment, examination of different N fertilizer rates revealed switchgrass yield increases over the range of 0, 80, or 160 kg N ha−1 year−1, while Mxg only showed yield increases between the low and medium N rates. This provides useful insights to crop management of two biofuel species and to enhance the predictive accuracy of process-based models, which are critical for developing bioenergy market systems in the SGP.

Coleoptera species of forensic importance from Brazil: an updated list

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Lúcia Massutti de Almeida

2015-12-01

Full Text Available ABSTRACT A list of the Coleoptera of importance from Brazil, based on published records was compiled. The checklist contains 345 species of 16 families allocated to 16 states of the country. In addition, three species of two families are registered for the first time. The fauna of Coleoptera of forensic importance is still not entirely known and future collection efforts and taxonomic reviews could increase the number of known species considerably in the near future.

Site and plant species are important determinants of the Methylobacterium community composition in the plant phyllosphere.

Science.gov (United States)

Knief, Claudia; Ramette, Alban; Frances, Lisa; Alonso-Blanco, Carlos; Vorholt, Julia A

2010-06-01

The plant phyllosphere constitutes a habitat for numerous microorganisms; among them are members of the genus Methylobacterium. Owing to the ubiquitous occurrence of methylobacteria on plant leaves, they represent a suitable target for studying plant colonization patterns. The influence of the factor site, host plant species, time and the presence of other phyllosphere bacteria on Methylobacterium community composition and population size were evaluated in this study. Leaf samples were collected from Arabidopsis thaliana or Medicago truncatula plants and from the surrounding plant species at several sites. The abundance of cultivable Methylobacterium clearly correlated with the abundance of other phyllosphere bacteria, suggesting that methylobacteria constitute a considerable and rather stable fraction of the phyllosphere microbiota under varying environmental conditions. Automated ribosomal intergenic spacer analysis (ARISA) was applied to characterize the Methylobacterium community composition and showed the presence of similar communities on A. thaliana plants at most sites in 2 consecutive years of sampling. A substantial part of the observed variation in the community composition was explained by site and plant species, especially in the case of the plants collected at the Arabidopsis sites (50%). The dominating ARISA peaks that were detected on A. thaliana plants were found on other plant species grown at the same site, whereas some different peaks were detected on A. thaliana plants from other sites. This indicates that site-specific factors had a stronger impact on the Methylobacterium community composition than did plant-specific factors and that the Methylobacterium-plant association is not highly host plant species specific.

Some safety considerations of liquid lithium as a fusion breeder material

International Nuclear Information System (INIS)

Jeppson, D.W.; Muhlestein, L.D.

1986-01-01

Test results and conclusions are presented for the reaction of steam with a high temperature lithium pool and for the reaction of high temperature lithium spray with a nitrogen atmosphere. The reactions are characterized and evaluated in regard to the potential for mobilization of radioactive species associated with the liquid breeder under postulated fusion reactor accident conditions. These evaluations include measured lithium temperature responses, atmosphere temperature and pressure responses, gas consumption and generation, aerosol quantities and particle size characterization, and potentially radioactive species releases. Conclusions are made as to the consequences of these safety considerations for the use of lithium as a fusion reactor breeder material

Employer Requirements to Work during Emergency Responses: Key Ethics Considerations.

Science.gov (United States)

Rutkow, Lainie; Taylor, Holly A; Powell, Tia

2017-03-01

Local health departments and their employees are at the forefront of emergency preparedness and response. Yet, recent studies have found that some local public health workers are unwilling to report to work in a variety of disaster scenarios. This can greatly compromise a response, as many local health departments need "all hands on deck" to effectively meet increased demands. To address these concerns, local health departments have employed varied policy strategies to ensure that employees do report to work. After describing different approaches taken by local health departments throughout the United States, we briefly identify and explore key ethics considerations that arise for local health departments when employees are required to report to work for emergency responses. We then discuss how these ethics considerations may inform local health department practices intended to promote a robust emergency response.

Enantioselective Separation of 4,8-DHT and Phytotoxicity of the Enantiomers on Various Plant Species

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Li Yang

2016-04-01

Full Text Available As a candidate for bioherbicide, 4,8-dihydroxy-1-tetralone (4,8-DHT was isolated from Caryospora callicarpa epicarp and its two enantiomers, S-(+-isosclerone and R-(−-regiolone, were separated by chiral high-performance liquid chromatography (HPLC on a Chiralcel OD column with chiral stationary phase (CSP-coated cellulose-tris(3,5-dimethylphenylcarbamate. Then, the phytotoxicity of 4,8-DHT and its enantiomers toward the seeds germination and seedling growth of the five tested plant species, including lettuce (Latuca sativa, radish (Raphanus sativus, cucumber (Cucumis sativus, onion (Allium cepa, and wheat (Triticum aestivum, were investigated and the results indicated a hormesis at low concentration of 4,8-DHT and its enantiomers, but a retardant effect at high concentration. Between the two enantiomers of 4,8-DHT, the S-(+-isosclerone was more toxic to seeds germination and seedling growth of the five tested plant species than the R-(−-regiolone, and also the phytotoxicity of S-(+-isosclerone varied with different plants. For example, S-(+-isosclerone was the most active to seedling growth of lettuce, indicating that S-(+-isosclerone had specific effects on different organisms. Thus, all of the chirality and concentration of 4,8-DHT, as well as the affected plant species, need to be taken into consideration in the development and utilization of 4,8-DHT.

Phylogeny of Fomitopsis pinicola: A species complex

Science.gov (United States)

John Haight; Gary A. Laursen; Jessie A. Glaeser; D. Lee. Taylor

2016-01-01

Fungal species with a broad distribution may exhibit considerable genetic variation over their geographic ranges. Variation may develop among populations based on geographic isolation, lack of migration, and genetic drift, though this genetic variation may not always be evident when examining phenotypic characters. Fomitopsis pinicola is an...

Predicting patterns of vulnerability to climate change in near coastal species using an algorithm-based risk assessment framework

Science.gov (United States)

Near-coastal (0-200 depth) ecosystems and species are under threat from increasing temperatures, ocean acidification, and sea level rise. However, species vary in their vulnerability to specific climatic changes and climate impacts will vary geographically. For management to resp...

Tasmanian tigers and polar bears: The documentary moving image and (species loss

Directory of Open Access Journals (Sweden)

Belinda Smaill

2015-04-01

Full Text Available In this essay I explore how two divergent examples of the nonfiction moving image can be understood in relation to the problem of representing species loss. The species that provide the platform for this consideration are the thylacine, better known as the Tasmanian tiger, and the polar bear. They represent the two contingencies of species loss: endangerment and extinction. My analysis is structured around moving images from the 1930s of the last known thylacine and the very different example of Arctic Tale (Adam Ravetch, Sarah Robertson, 2007, a ‘Disneyfied’ film that dramatises climate change and its impact on the polar bear. Species loss is frequently perceived in a humanist sense, reflecting how we ‘imagine ourselves’ or anthropocentric charactersations of non-human others. I offer a close analysis of the two films, examining the problem of representing extinction through a consideration of the play of absence and presence, vitality and extinguishment, that characterises both the ontology of cinema and narratives about species loss.

Prioritization of Wood Species Utilized for Furniture Making in ...

African Journals Online (AJOL)

The preference for wood species varied among the three cities and among the three scales of furniture factories. However, Mansonia altissima was most preferred in the three cities with rates of 99.0%, 97.4% and 97.7% in Lagos, Ibadan and Benin respectively. 39 wood species were compiled from the lists of the three cities ...

Clutch size in populations and species of cnemidophorines (Squamata: Teiidae on the eastern coast of Brazil

Directory of Open Access Journals (Sweden)

VANDERLAINE A. MENEZES

2014-06-01

Full Text Available We analyzed some reproductive aspects of 16 coastal populations, belonging to five lizard species (A. ocellifera, A. abaetensis, A. nativo, A. littoralis and C. lacertoides from different restinga habitats along the eastern coast of Brazil. This study aimed to evaluate to what extent the reproductive aspects vary geographically and among species. For each female, we recorded the number of vitellogenic follicles, size and color of the largest follicle, presence and size of corpora lutea, and number and size of oviductal eggs. Clutch size of almost all coastal populations/species of Ameivula had little variation and most clutches were composed of two eggs. There was a significant relationship between female size and the mean clutch size when females from different species were pooled. Mean egg volume, among species, varied from 420 to 655 mm3. Relative clutch mass varied from 0.129 to 0.159 and did not differ significantly among species. We concluded that the five coastal species studied (four bisexuals and one parthenogenetic had similar reproductive characteristics. Most of them presented multiple clutches, low clutch size and low relative clutch mass, similar to other species in the genus and to unisexual and bisexual species of the Teiidae family.

Species richness alone does not predict cultural ecosystem service value

Science.gov (United States)

Graves, Rose A.; Pearson, Scott M.; Turner, Monica G.

2017-01-01

Many biodiversity-ecosystem services studies omit cultural ecosystem services (CES) or use species richness as a proxy and assume that more species confer greater CES value. We studied wildflower viewing, a key biodiversity-based CES in amenity-based landscapes, in Southern Appalachian Mountain forests and asked (i) How do aesthetic preferences for wildflower communities vary with components of biodiversity, including species richness?; (ii) How do aesthetic preferences for wildflower communities vary across psychographic groups?; and (iii) How well does species richness perform as an indicator of CES value compared with revealed social preferences for wildflower communities? Public forest visitors (n = 293) were surveyed during the summer of 2015 and asked to choose among images of wildflower communities in which flower species richness, flower abundance, species evenness, color diversity, and presence of charismatic species had been digitally manipulated. Aesthetic preferences among images were unrelated to species richness but increased with more abundant flowers, greater species evenness, and greater color diversity. Aesthetic preferences were consistent across psychographic groups and unaffected by knowledge of local flora or value placed on wildflower viewing. When actual wildflower communities (n = 54) were ranked based on empirically measured flower species richness or wildflower viewing utility based on multinomial logit models of revealed preferences, rankings were broadly similar. However, designation of hotspots (CES values above the median) based on species richness alone missed 27% of wildflower viewing utility hotspots. Thus, conservation priorities for sustaining CES should incorporate social preferences and consider multiple dimensions of biodiversity that underpin CES supply. PMID:28320953

Sex ratio of five species of pelagic copepods from Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Saraswathy, M.; Santhakumari, V.

Sex ratio in five species from south and southeast coast of India varied remarkably. Five species were selected for the present investigation. Range in the percentage of males was from 8 to 121 in @iUndinula vulgaris@@ (Dana), 16-425 in @i...

Progress on MEVVA source VARIS at GSI

Science.gov (United States)

Adonin, A.; Hollinger, R.

2018-05-01

For the last few years, the development of the VARIS (vacuum arc ion source) was concentrated on several aspects. One of them was the production of high current ion beams of heavy metals such as Au, Pb, and Bi. The requested ion charge state for these ion species is 4+. This is quite challenging to produce in vacuum arc driven sources for reasonable beam pulse length (>120 µs) due to the physical properties of these elements. However, the situation can be dramatically improved by using the composite materials or alloys with enhanced physical properties of the cathodes. Another aspect is an increase of the beam brilliance for intense U4+ beams by the optimization of the geometry of the extraction system. A new 7-hole triode extraction system allows an increase of the extraction voltage from 30 kV to 40 kV and also reduces the outer aperture of the extracted ion beam. Thus, a record beam brilliance for the U4+ beam in front of the RFQ (Radio-Frequency Quadrupole) has been achieved, exceeding the RFQ space charge limit for an ion current of 15 mA. Several new projectiles in the middle-heavy region have been successfully developed from VARIS to fulfill the requirements of the future FAIR (Facility for Antiproton and Ion Research) programs. An influence of an auxiliary gas on the production performance of certain ion charge states as well as on operation stability has been investigated. The optimization of the ion source parameters for a maximum production efficiency and highest particle current in front of the RFQ has been performed. The next important aspect of the development will be the increase of the operation repetition rate of VARIS for all elements especially for uranium to 2.7 Hz in order to provide the maximum availability of high current ion beams for future FAIR experiments.

Species-specific considerations in using the fish embryo test as an alternative to identify endocrine disruption.

Science.gov (United States)

Schiller, Viktoria; Zhang, Xiaowei; Hecker, Markus; Schäfers, Christoph; Fischer, Rainer; Fenske, Martina

2014-10-01

A number of regulations have been implemented that aim to control the release of potentially adverse endocrine disrupters into the aquatic environment based on evidence from laboratory studies. Currently, such studies rely on testing approaches with adult fish because reliable alternatives have not been validated so far. Fish embryo tests have been proposed as such an alternative, and here we compared two species (medaka and zebrafish) to determine their suitability for the assessment of substances with estrogenic and anti-androgenic activity. Changes in gene expression (in here the phrase gene expression is used synonymously to gene transcription, although it is acknowledged that gene expression is additionally regulated, e.g., by translation and protein stability) patterns between the two species were compared in short term embryo exposure tests (medaka: 7-day post fertilization [dpf]; zebrafish: 48 and 96h post fertilization [hpf]) by using relative quantitative real-time RT-PCR. The tested genes were related to the hypothalamic-gonadal-axis and early steroidogenesis. Test chemicals included 17α-ethinylestradiol and flutamide as estrogenic and anti-androgenic reference compounds, respectively, as well as five additional substances with endocrine activities, namely bisphenol A, genistein, prochloraz, linuron and propanil. Estrogenic responses were comparable in 7-dpf medaka and 48/96-hpf zebrafish embryos and included transcriptional upregulation of aromatase b, vitellogenin 1 as well as steroidogenic genes, suggesting that both species reliably detected exposure to estrogenic compounds. However, anti-androgenic responses differed between the two species, with each species providing specific information concerning the mechanism of anti-androgenic disruption in fish embryos. Although small but significant changes in the expression of selected genes was observed in 48-hpf zebrafish embryos, exposure prolonged to 96hpf was necessary to obtain a response indicative

Performance improvement of ERP-based brain-computer interface via varied geometric patterns.

Science.gov (United States)

Ma, Zheng; Qiu, Tianshuang

2017-12-01

Recently, many studies have been focusing on optimizing the stimulus of an event-related potential (ERP)-based brain-computer interface (BCI). However, little is known about the effectiveness when increasing the stimulus unpredictability. We investigated a new stimulus type of varied geometric pattern where both complexity and unpredictability of the stimulus are increased. The proposed and classical paradigms were compared in within-subject experiments with 16 healthy participants. Results showed that the BCI performance was significantly improved for the proposed paradigm, with an average online written symbol rate increasing by 138% comparing with that of the classical paradigm. Amplitudes of primary ERP components, such as N1, P2a, P2b, N2, were also found to be significantly enhanced with the proposed paradigm. In this paper, a novel ERP BCI paradigm with a new stimulus type of varied geometric pattern is proposed. By jointly increasing the complexity and unpredictability of the stimulus, the performance of an ERP BCI could be considerably improved.

Seasonal species interactions minimize the impact of species turnover on the likelihood of community persistence.

Science.gov (United States)

Saavedra, Serguei; Rohr, Rudolf P; Fortuna, Miguel A; Selva, Nuria; Bascompte, Jordi

2016-04-01

Many of the observed species interactions embedded in ecological communities are not permanent, but are characterized by temporal changes that are observed along with abiotic and biotic variations. While work has been done describing and quantifying these changes, little is known about their consequences for species coexistence. Here, we investigate the extent to which changes of species composition impact the likelihood of persistence of the predator-prey community in the highly seasonal Białowieza Primeval Forest (northeast Poland), and the extent to which seasonal changes of species interactions (predator diet) modulate the expected impact. This likelihood is estimated extending recent developments on the study of structural stability in ecological communities. We find that the observed species turnover strongly varies the likelihood of community persistence between summer and winter. Importantly, we demonstrate that the observed seasonal interaction changes minimize the variation in the likelihood of persistence associated with species turnover across the year. We find that these community dynamics can be explained as the coupling of individual species to their environment by minimizing both the variation in persistence conditions and the interaction changes between seasons. Our results provide a homeostatic explanation for seasonal species interactions and suggest that monitoring the association of interactions changes with the level of variation in community dynamics can provide a good indicator of the response of species to environmental pressures.

Ecological and economic determinants of invasive tree species on Alabama forestland

Science.gov (United States)

Anwar Hussain; Changyou Sun; Xiaoping Zhou; Ian A. Munn

2008-01-01

The spread of invasive tree species has caused increasing harm to the environment. This study was motivated by the considerations that earlier studies generally ignored the role of economic factors related to the occurrence and abundance of invasive species, and empirical analyses of invasive trees on forestland have been inadequate. We assessed the impact of...

The temporal variability of species densities

International Nuclear Information System (INIS)

Redfearn, A.; Pimm, S.L.

1993-01-01

Ecologists use the term 'stability' to mean to number of different things (Pimm 1984a). One use is to equate stability with low variability in population density over time (henceforth, temporal variability). Temporal variability varies greatly from species to species, so what effects it? There are at least three sets of factors: the variability of extrinsic abiotic factors, food web structure, and the intrinsic features of the species themselves. We can measure temporal variability using at least three statistics: the coefficient of variation of density (CV); the standard deviation of the logarithms of density (SDL); and the variance in the differences between logarithms of density for pairs of consecutive years (called annual variability, hence AV, b y Wolda 1978). There are advantages and disadvantages to each measure (Williamson 1984), though in our experience, the measures are strongly correlated across sets of taxonomically related species. The increasing availability of long-term data sets allows one to calculate these statistics for many species and so to begin to understand the various causes of species differences in temporal variability

The influence of engineering design considerations on species recruitment and succession on coastal defence structures

OpenAIRE

Jackson, Juliette Elizabeth

2015-01-01

Engineering design considerations of artificial coastal structures were tested to resemble as far as possible the nearest natural equivalent habitat, ecologically valuable rocky shores, as a potential management option. Coastal areas around the world attract urbanisation but these transitional areas between sea and land are inherently vulnerable to risk of flooding and erosion. Thus hard structures are often built in sensitive coastal environments to defend assets such as property and infrast...

Species richness and occupancy estimation in communities subject to temporary emigration

Science.gov (United States)

Kery, M.; Royle, J. Andrew; Plattner, M.; Dorazio, R.M.

2009-01-01

Species richness is the most common biodiversity metric, although typically some species remain unobserved. Therefore, estimates of species richness and related quantities should account for imperfect detectability. Community dynamics can often be represented as superposition of species-specific phenologies (e. g., in taxa with well-defined flight [insects], activity [rodents], or vegetation periods [plants]). We develop a model for such predictably open communities wherein species richness is expressed as the sum over observed and unobserved species of estimated species-specific and site-specific occurrence indicators and where seasonal occurrence is modeled as a species-specific function of time. Our model is a multispecies extension of a multistate model with one unobservable state and represents a parsimonious way of dealing with a widespread form of 'temporary emigration.'' For illustration we use Swiss butterfly monitoring data collected under a robust design (RD); species were recorded on 13 transects during two secondary periods within data, where secondary samples are pooled. The latter model yielded unrealistically high estimates of total community size of 274 species. In contrast, estimates were similar under models applied to RD data with constant (122) or seasonally varying (126) detectability for each species, but the former was more parsimonious and therefore used for inference. Per transect, 6 44 (mean 21.1) species were detected. Species richness estimates averaged 29.3; therefore only 71% (range 32-92%) of all species present were ever detected. In any primary period, 0.4-5.6 species present were overlooked. Detectability varied by species and averaged 0.88 per primary sampling period. Our modeling framework is extremely flexible; extensions such as covariates for the occurrence or detectability of individual species are easy. It should be useful for communities with a predictable form of temporary emigration where rigorous estimation of community

Climatic associations of British species distributions show good transferability in time but low predictive accuracy for range change.

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Giovanni Rapacciuolo

Full Text Available Conservation planners often wish to predict how species distributions will change in response to environmental changes. Species distribution models (SDMs are the primary tool for making such predictions. Many methods are widely used; however, they all make simplifying assumptions, and predictions can therefore be subject to high uncertainty. With global change well underway, field records of observed range shifts are increasingly being used for testing SDM transferability. We used an unprecedented distribution dataset documenting recent range changes of British vascular plants, birds, and butterflies to test whether correlative SDMs based on climate change provide useful approximations of potential distribution shifts. We modelled past species distributions from climate using nine single techniques and a consensus approach, and projected the geographical extent of these models to a more recent time period based on climate change; we then compared model predictions with recent observed distributions in order to estimate the temporal transferability and prediction accuracy of our models. We also evaluated the relative effect of methodological and taxonomic variation on the performance of SDMs. Models showed good transferability in time when assessed using widespread metrics of accuracy. However, models had low accuracy to predict where occupancy status changed between time periods, especially for declining species. Model performance varied greatly among species within major taxa, but there was also considerable variation among modelling frameworks. Past climatic associations of British species distributions retain a high explanatory power when transferred to recent time--due to their accuracy to predict large areas retained by species--but fail to capture relevant predictors of change. We strongly emphasize the need for caution when using SDMs to predict shifts in species distributions: high explanatory power on temporally-independent records

Cytotoxicity of InP/ZnS quantum dots related to reactive oxygen species generation

Science.gov (United States)

Chibli, Hicham; Carlini, Lina; Park, Soonhyang; Dimitrijevic, Nada M.; Nadeau, Jay L.

2011-06-01

Indium phosphide (InP) quantum dots (QDs) have emerged as a presumably less hazardous alternative to cadmium-based particles, but their cytotoxicity has not been well examined. Although their constituent elements are of very low toxicity to cells in culture, they nonetheless exhibit phototoxicity related to generation of reactive oxygen species by excited electrons and/or holes interacting with water and molecular oxygen. Using spin-trap electron paramagnetic resonance (EPR) spectroscopy and reporter assays, we find a considerable amount of superoxide and a small amount of hydroxyl radical formed under visible illumination of biocompatible InP QDs with a single ZnS shell, comparable to what is seen with CdTe. A double thickness shell reduces the reactive oxygen species concentration approximately two-fold. Survival assays in five cell lines correspondingly indicate a distinct reduction in toxicity with the double-shell InP QDs. Toxicity varies significantly across cell lines according to the efficiency of uptake, being overall significantly less than what is seen with CdTe or CdSe/ZnS. This indicates that InP QDs are a useful alternative to cadmium-containing QDs, while remaining capable of electron-transfer processes that may be undesirable or which may be exploited for photosensitization applications.

Cytotoxicity of InP/ZnS quantum dots related to reactive oxygen species generation.

Energy Technology Data Exchange (ETDEWEB)

Chibli, H.; Carlini, L.; Park, S.; Dimitrijevic, N. M.; Nadeau, J. L. (Center for Nanoscale Materials); ( CSE); (McGill Univ.)

2011-01-01

Indium phosphide (InP) quantum dots (QDs) have emerged as a presumably less hazardous alternative to cadmium-based particles, but their cytotoxicity has not been well examined. Although their constituent elements are of very low toxicity to cells in culture, they nonetheless exhibit phototoxicity related to generation of reactive oxygen species by excited electrons and/or holes interacting with water and molecular oxygen. Using spin-trap electron paramagnetic resonance (EPR) spectroscopy and reporter assays, we find a considerable amount of superoxide and a small amount of hydroxyl radical formed under visible illumination of biocompatible InP QDs with a single ZnS shell, comparable to what is seen with CdTe. A double thickness shell reduces the reactive oxygen species concentration approximately two-fold. Survival assays in five cell lines correspondingly indicate a distinct reduction in toxicity with the double-shell InP QDs. Toxicity varies significantly across cell lines according to the efficiency of uptake, being overall significantly less than what is seen with CdTe or CdSe/ZnS. This indicates that InP QDs are a useful alternative to cadmium-containing QDs, while remaining capable of electron-transfer processes that may be undesirable or which may be exploited for photosensitization applications.

Why abundant tropical tree species are phylogenetically old.

Science.gov (United States)

Wang, Shaopeng; Chen, Anping; Fang, Jingyun; Pacala, Stephen W

2013-10-01

Neutral models of species diversity predict patterns of abundance for communities in which all individuals are ecologically equivalent. These models were originally developed for Panamanian trees and successfully reproduce observed distributions of abundance. Neutral models also make macroevolutionary predictions that have rarely been evaluated or tested. Here we show that neutral models predict a humped or flat relationship between species age and population size. In contrast, ages and abundances of tree species in the Panamanian Canal watershed are found to be positively correlated, which falsifies the models. Speciation rates vary among phylogenetic lineages and are partially heritable from mother to daughter species. Variable speciation rates in an otherwise neutral model lead to a demographic advantage for species with low speciation rate. This demographic advantage results in a positive correlation between species age and abundance, as found in the Panamanian tropical forest community.

Non-climatic thermal adaptation: implications for species' responses to climate warming.

Science.gov (United States)

Marshall, David J; McQuaid, Christopher D; Williams, Gray A

2010-10-23

There is considerable interest in understanding how ectothermic animals may physiologically and behaviourally buffer the effects of climate warming. Much less consideration is being given to how organisms might adapt to non-climatic heat sources in ways that could confound predictions for responses of species and communities to climate warming. Although adaptation to non-climatic heat sources (solar and geothermal) seems likely in some marine species, climate warming predictions for marine ectotherms are largely based on adaptation to climatically relevant heat sources (air or surface sea water temperature). Here, we show that non-climatic solar heating underlies thermal resistance adaptation in a rocky-eulittoral-fringe snail. Comparisons of the maximum temperatures of the air, the snail's body and the rock substratum with solar irradiance and physiological performance show that the highest body temperature is primarily controlled by solar heating and re-radiation, and that the snail's upper lethal temperature exceeds the highest climatically relevant regional air temperature by approximately 22°C. Non-climatic thermal adaptation probably features widely among marine and terrestrial ectotherms and because it could enable species to tolerate climatic rises in air temperature, it deserves more consideration in general and for inclusion into climate warming models.

Wood anatomy of the Brazilian species of Swartizia and considerations within the tribe Swartzieae

Science.gov (United States)

Veronica Angyalossy-Alfonso

2002-01-01

Fifty-one Brazilian species and varieties of Swartzia Schreber and eight other genera from the tribe Swartzieae were examined. Features with the greatest diagnostic value for the tribe are intervascular pit size, ray width and frequency, storied structure, axial parenchyma strand length, parenchyma band width, and vessel diameter. We analyzed the wood anatomical data...

Identification and characterization of the reptilian GnRH-II gene in the leopard gecko, Eublepharis macularius, and its evolutionary considerations.

Science.gov (United States)

Ikemoto, Tadahiro; Park, Min Kyun

2003-10-16

To elucidate the molecular phylogeny and evolution of a particular peptide, one must analyze not the limited primary amino acid sequences of the low molecular weight mature polypeptide, but rather the sequences of the corresponding precursors from various species. Of all the structural variants of gonadotropin-releasing hormone (GnRH), GnRH-II (chicken GnRH-II, or cGnRH-II) is remarkably conserved without any sequence substitutions among vertebrates, but its precursor sequences vary considerably. We have identified and characterized the full-length complementary DNA (cDNA) encoding the GnRH-II precursor and determined its genomic structure, consisting of four exons and three introns, in a reptilian species, the leopard gecko Eublepharis macularius. This is the first report about the GnRH-II precursor cDNA/gene from reptiles. The deduced leopard gecko prepro-GnRH-II polypeptide had the highest identities with the corresponding polypeptides of amphibians. The GnRH-II precursor mRNA was detected in more than half of the tissues and organs examined. This widespread expression is consistent with the previous findings in several species, though the roles of GnRH outside the hypothalamus-pituitary-gonadal axis remain largely unknown. Molecular phylogenetic analysis combined with sequence comparison showed that the leopard gecko is more similar to fishes and amphibians than to eutherian mammals with respect to the GnRH-II precursor sequence. These results strongly suggest that the divergence of the GnRH-II precursor sequences seen in eutherian mammals may have occurred along with amniote evolution.

CALORIFIC PROPERTIES OF WASTES FROM SOME EXOTIC WOOD SPECIES

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Aurel LUNGULEASA

2016-03-01

Full Text Available This paper aims to present some results about the calorific properties of biomass wastes from exotic species used as fuels. There are presented the main characteristics of biomass energy, respectively the low and high calorific value, burning speed and energy efficiency. Methodology takes into consideration the equipment, wooden species and relationships for calorific determination. The final conclusion resulting from the experiments is that the biomass of exotic species is as good as any other woody biomass, when is used as fuel, because the calorific properties are closely, even slightly higher than of classical fuels.

[A complex of blood-sucking mosquitoes (Diptera, Culicidae) in the focus of West Nile fever in the Volgograd Region. III. Species feeding on birds and man and the rhythms of their nocturnal activity].

Science.gov (United States)

Lopatina, Iu V; Bezzhonova, O V; Fedorova, M V; Bulgakova, T V; Platonov, A E

2007-01-01

The rate and nocturnal rhythm of mosquito attacks of birds and human beings were studied in the open biotopes of Volgograd and its vicinity in 2004. Thirteen and 11 species of the subfamily Culicinae were collected under the Berezantsev bell and from the traps containing a chicken (a hen), respectively; of them 9 species were common. The mosquitoes of an Anopheles maculipennis complex were caught in a small portion to the traps of both types. Most species of Aedes were highly anthropophilic, showed the minimum activity at night and their abundance considerably decreased by the early transmission period. Among the species that were active during the transmission period, Ae. vexans, Coq. richiardii, and Cx. modestus more intensively attacked a human being than birds and Cx. pipiens was frequently attracted into the hen traps. The attraction of each species of the caught varied during the transmission period. The maximum attacks of Cx. modestus and Cx. pipiens on man and birds coincide and those of Coq. Richiardii and Cx. pipiens on man was observed earlier than on birds. A possible role of mosquitoes of different species in the epizootic and epidemiological processes is discussed.

Functional traits drive the contribution of solar radiation to leaf litter decomposition among multiple arid-zone species.

Science.gov (United States)

Pan, Xu; Song, Yao-Bin; Liu, Guo-Fang; Hu, Yu-Kun; Ye, Xue-Hua; Cornwell, William K; Prinzing, Andreas; Dong, Ming; Cornelissen, Johannes H C

2015-08-18

In arid zones, strong solar radiation has important consequences for ecosystem processes. To better understand carbon and nutrient dynamics, it is important to know the contribution of solar radiation to leaf litter decomposition of different arid-zone species. Here we investigated: (1) whether such contribution varies among plant species at given irradiance regime, (2) whether interspecific variation in such contribution correlates with interspecific variation in the decomposition rate under shade; and (3) whether this correlation can be explained by leaf traits. We conducted a factorial experiment to determine the effects of solar radiation and environmental moisture for the mass loss and the decomposition constant k-values of 13 species litters collected in Northern China. The contribution of solar radiation to leaf litter decomposition varied significantly among species. Solar radiation accelerated decomposition in particular in the species that already decompose quickly under shade. Functional traits, notably specific leaf area, might predict the interspecific variation in that contribution. Our results provide the first empirical evidence for how the effect of solar radiation on decomposition varies among multiple species. Thus, the effect of solar radiation on the carbon flux between biosphere and atmosphere may depend on the species composition of the vegetation.

Spall Strength Measurements of Concrete for Varying Aggregate Sizes

International Nuclear Information System (INIS)

Chhabildas, Lalit C.; Kipp, Marlin E.; Reinhart, William D.; Wilson, Leonard T.

1999-01-01

Controlled impact experiments have been performed to determine the spall strength of four different concrete compositions. The four concrete compositions are identified as, 'SAC-5, CSPC', (''3/4'') large, and (''3/8'') small, Aggregate. They differ primarily in aggregate size but with average densities varying by less than five percent. Wave profiles from sixteen experiments, with shock amplitudes of 0.07 to 0.55 GPa, concentrate primarily within the elastic regime. Free-surface particle velocity measurements indicate consistent pullback signals in the release profiles, denoting average span strength of approximately 40 MPa. It is the purpose of this paper to present spall measurements under uniaxial strain loading. Notwithstanding considerable wave structure that is a unique characteristic to the heterogeneous nature of the scaled concrete, the spall amplitudes appear reproducible and consistent over the pressure range reported in this study

Integrative taxonomy and preliminary assessment of species limits in the Liolaemus walkeri complex (Squamata, Liolaemidae with descriptions of three new species from Peru

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Cesar Aguilar

2013-12-01

Full Text Available Species delimitation studies based on integrative taxonomic approaches have received considerable attention in the last few years, and have provided the strongest hypotheses of species boundaries. We used three lines of evidence (molecular, morphological, and niche envelopes to test for species boundaries in Peruvian populations of the Liolaemus walkeri complex. Our results show that different lines of evidence and analyses are congruent in different combinations, for unambiguous delimitation of three lineages that were “hidden” within known species, and now deserve species status. Our phylogenetic analysis shows that L. walkeri, L. tacnae and the three new species are strongly separated from other species assigned to the alticolor-bibronii group. Few conventional morphological characters distinguish the new species from closely related taxa and this highlights the need to integrate other sources of data to erect strong hypothesis of species limits. A taxonomic key for known Peruvian species of the subgenus Lioalemus is provided.

Keeping All the PIECES: Phylogenetically Informed Ex Situ Conservation of Endangered Species.

Science.gov (United States)

Larkin, Daniel J; Jacobi, Sarah K; Hipp, Andrew L; Kramer, Andrea T

2016-01-01

Ex situ conservation in germplasm and living collections is a major focus of global plant conservation strategies. Prioritizing species for ex situ collection is a necessary component of this effort for which sound strategies are needed. Phylogenetic considerations can play an important role in prioritization. Collections that are more phylogenetically diverse are likely to encompass more ecological and trait variation, and thus provide stronger conservation insurance and richer resources for future restoration efforts. However, phylogenetic criteria need to be weighed against other, potentially competing objectives. We used ex situ collection and threat rank data for North American angiosperms to investigate gaps in ex situ coverage and phylogenetic diversity of collections and to develop a flexible framework for prioritizing species across multiple objectives. We found that ex situ coverage of 18,766 North American angiosperm taxa was low with respect to the most vulnerable taxa: just 43% of vulnerable to critically imperiled taxa were in ex situ collections, far short of a year-2020 goal of 75%. In addition, species held in ex situ collections were phylogenetically clustered (P species been drawn at random. These patterns support incorporating phylogenetic considerations into ex situ prioritization in a manner balanced with other criteria, such as vulnerability. To meet this need, we present the 'PIECES' index (Phylogenetically Informed Ex situ Conservation of Endangered Species). PIECES integrates phylogenetic considerations into a flexible framework for prioritizing species across competing objectives using multi-criteria decision analysis. Applying PIECES to prioritizing ex situ conservation of North American angiosperms, we show strong return on investment across multiple objectives, some of which are negatively correlated with each other. A spreadsheet-based decision support tool for North American angiosperms is provided; this tool can be customized to

Risky behavior and its effect on survival: snowshoe hare behavior under varying moonlight conditions

Science.gov (United States)

Gigliotti, Laura C.; Diefenbach, Duane R.

2018-01-01

Predation and predation risk can exert strong influences on the behavior of prey species. However, risk avoidance behaviors may vary among populations of the same species. We studied a population of snowshoe hares (Lepus americanus) near the southern edge of their range, in Pennsylvania. This population occupies different habitat types, experiences different environmental conditions, and are exposed to different predator species and densities than northern hare populations; therefore, they might exhibit differences in risk avoidance behaviors. We analyzed hare survival, movement rates, and habitat use under different levels of predation risk, as indexed by moonlight. Similar to previous work, we found snowshoe hare survival decreased with increased moon illumination during the winter, but we found differences in behavioral responses to increased predation risk. We found that snowshoe hares did not reduce movement rates during high‐risk nights, but instead found that hares selected areas with denser canopy cover, compared to low‐risk nights. We suggest that behavioral plasticity in response to predation risk allows populations of the same species to respond to localized conditions.

Are range-size distributions consistent with species-level heritability?

DEFF Research Database (Denmark)

Borregaard, Michael Krabbe; Gotelli, Nicholas; Rahbek, Carsten

2012-01-01

The concept of species-level heritability is widely contested. Because it is most likely to apply to emergent, species-level traits, one of the central discussions has focused on the potential heritability of geographic range size. However, a central argument against range-size heritability has...... been that it is not compatible with the observed shape of present-day species range-size distributions (SRDs), a claim that has never been tested. To assess this claim, we used forward simulation of range-size evolution in clades with varying degrees of range-size heritability, and compared the output...

Species-delimitation and phylogenetic analyses of some cosmopolitan species of Hypnea (Rhodophyta) reveal synonyms and misapplied names to H. cervicornis, including a new species from Brazil.

Science.gov (United States)

de Jesus, Priscila Barreto; Nauer, Fabio; Lyra, Goia de Mattos; Cassano, Valéria; Oliveira, Mariana Cabral; Nunes, José Marcos de Castro; Schnadelbach, Alessandra Selbach

2016-10-01

Hypnea has an intricate nomenclatural history due to a wide pantropical distribution and considerable morphological variation. Recent molecular studies have provided further clarification on the systematics of the genus; however, species of uncertain affinities remain due to flawed taxonomic identification. Detailed analyses coupled with literature review indicated a strong relationship among H. aspera, H. cervicornis, H. flexicaulis, and H. tenuis, suggesting a need for further taxonomic studies. Here, we analyzed sequences from two molecular markers (COI-5P and rbcL) and performed several DNA-based delimitation methods (mBGD, ABGD, SPN, PTP and GMYC). These molecular approaches were contrasted with morphological and phylogenetic evidence from type specimens and/or topotype collections of related species under a conservative approach. Our results demonstrate that H. aspera and H. flexicaulis represent heterotypic synonyms of H. cervicornis and indicate the existence of a misidentified Hypnea species, widely distributed on the Brazilian coast, described here as a new species: H. brasiliensis. Finally, inconsistencies observed among our results based on six different species delimitation methods evidence the need for adequate sampling and marker choice for different methods. © 2016 Phycological Society of America.

Phase behaviour of oat β-glucan/sodium caseinate mixtures varying in molecular weight.

Science.gov (United States)

Agbenorhevi, Jacob K; Kontogiorgos, Vassilis; Kasapis, Stefan

2013-05-01

The isothermal phase behaviour at 5 °C of mixtures of sodium caseinate and oat β-glucan isolates varying in molecular weight (MW) was investigated by means of phase diagram construction, rheometry, fluorescence microscopy and electrophoresis. Phase diagrams indicated that the compatibility of the β-glucan/sodium caseinate system increases as β-glucan MW decreases. Images of mixtures taken at various biopolymer concentrations revealed phase separated domains. Results also revealed that at the state of thermodynamic equilibrium, lower MW samples yielded considerable viscosity in the mixture. At equivalent hydrodynamic volume of β-glucan in the mixtures, samples varying in molecular weight exhibited similar flow behaviour. A deviation dependent on the protein concentration was observed for the high MW sample in the concentrated regime due to the size of β-glucan aggregates formed. Results demonstrate that by controlling the structural features of β-glucan in mixtures with sodium caseinate, informed manipulation of rheological properties in these systems can be achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

Seed banks as a source of vegetation regeneration to support the recovery of degraded rivers: A comparison of river reaches of varying condition.

Science.gov (United States)

O'Donnell, Jessica; Fryirs, Kirstie A; Leishman, Michelle R

2016-01-15

Anthropogenic disturbance has contributed to widespread geomorphic adjustment and the degradation of many rivers. This research compares for river reaches of varying condition, the potential for seed banks to support geomorphic river recovery through vegetation regeneration. Seven river reaches in the lower Hunter catchment of south-eastern Australia were assessed as being in poor, moderate, or good condition, based on geomorphic and ecological indicators. Seed bank composition within the channel and floodplain (determined in a seedling emergence study) was compared to standing vegetation. Seed bank potential for supporting geomorphic recovery was assessed by measuring native species richness, and the abundance of different plant growth forms, with consideration of the roles played by different growth forms in geomorphic adjustment. The exotic seed bank was considered a limiting factor for achieving ecological restoration goals, and similarly analysed. Seed bank native species richness was comparable between the reaches, and regardless of condition, early successional and pioneer herbs, sedges, grasses and rushes dominated the seed bank. The capacity for these growth forms to colonise and stabilise non-cohesive sediments and initiate biogeomorphic succession, indicates high potential for the seed banks of even highly degraded reaches to contribute to geomorphic river recovery. However, exotic propagules increasingly dominated the seed banks of moderate and poor condition reaches and reflected increasing encroachment by terrestrial exotic vegetation associated with riparian degradation. As the degree of riparian degradation increases, the resources required to control the regeneration of exotic species will similarly increase, if seed bank-based regeneration is to contribute to both geomorphic and ecological restoration goals. Copyright © 2015 Elsevier B.V. All rights reserved.

An updated checklist of mosquito species (Diptera: Culicidae) from Madagascar

Science.gov (United States)

Tantely, Michaël Luciano; Le Goff, Gilbert; Boyer, Sébastien; Fontenille, Didier

2016-01-01

An updated checklist of 235 mosquito species from Madagascar is presented. The number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species). This annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. The 235 species belong to 14 genera: Aedeomyia (3 species), Aedes (35 species), Anopheles (26 species), Coquillettidia (3 species), Culex (at least 50 species), Eretmapodites (4 species), Ficalbia (2 species), Hodgesia (at least one species), Lutzia (one species), Mansonia (2 species), Mimomyia (22 species), Orthopodomyia (8 species), Toxorhynchites (6 species), and Uranotaenia (73 species). Due to non-deciphered species complexes, several species remain undescribed. The main remarkable characteristic of Malagasy mosquito fauna is the high biodiversity with 138 endemic species (59%). Presence and abundance of species, and their association, in a given location could be a bio-indicator of environmental particularities such as urban, rural, forested, deforested, and mountainous habitats. Finally, taking into account that Malagasy culicidian fauna includes 64 species (27%) with a known medical or veterinary interest in the world, knowledge of their biology and host preference summarized in this paper improves understanding of their involvement in pathogen transmission in Madagascar. PMID:27101839

An updated checklist of mosquito species (Diptera: Culicidae from Madagascar

Directory of Open Access Journals (Sweden)

Tantely Michaël Luciano

2016-01-01

Full Text Available An updated checklist of 235 mosquito species from Madagascar is presented. The number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species. This annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. The 235 species belong to 14 genera: Aedeomyia (3 species, Aedes (35 species, Anopheles (26 species, Coquillettidia (3 species, Culex (at least 50 species, Eretmapodites (4 species, Ficalbia (2 species, Hodgesia (at least one species, Lutzia (one species, Mansonia (2 species, Mimomyia (22 species, Orthopodomyia (8 species, Toxorhynchites (6 species, and Uranotaenia (73 species. Due to non-deciphered species complexes, several species remain undescribed. The main remarkable characteristic of Malagasy mosquito fauna is the high biodiversity with 138 endemic species (59%. Presence and abundance of species, and their association, in a given location could be a bio-indicator of environmental particularities such as urban, rural, forested, deforested, and mountainous habitats. Finally, taking into account that Malagasy culicidian fauna includes 64 species (27% with a known medical or veterinary interest in the world, knowledge of their biology and host preference summarized in this paper improves understanding of their involvement in pathogen transmission in Madagascar.

Volitional components of consciousness vary across wakefulness, dreaming and lucid dreaming

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Martin eDresler

2014-01-01

Full Text Available Consciousness is a multifaceted concept; its different aspects vary across species, vigilance states or health conditions. While basal aspects of consciousness like perceptions and emotions are present in many states and species, higher-order aspects like reflective or volitional capabilities seem to be most pronounced in awake humans. Here we assess the experience of volition across different states of consciousness: 10 frequent lucid dreamers rated different aspects of volition according to the Volitional Components Questionnaire for phases of normal dreaming, lucid dreaming and wakefulness. Overall, experienced volition was comparable for lucid dreaming and wakefulness, and rated significantly higher for both states compared to non-lucid dreaming. However, three subscales showed specific differences across states of consciousness: planning ability was most pronounced during wakefulness, intention enactment most pronounced during lucid dreaming, and self-determination most pronounced during both wakefulness and lucid dreaming. Our data confirm the multifaceted nature of consciousness: different higher-order aspects of consciousness are differentially expressed across different conscious states.

Volitional components of consciousness vary across wakefulness, dreaming and lucid dreaming.

Science.gov (United States)

Dresler, Martin; Eibl, Leandra; Fischer, Christian F J; Wehrle, Renate; Spoormaker, Victor I; Steiger, Axel; Czisch, Michael; Pawlowski, Marcel

2014-01-01

Consciousness is a multifaceted concept; its different aspects vary across species, vigilance states, or health conditions. While basal aspects of consciousness like perceptions and emotions are present in many states and species, higher-order aspects like reflective or volitional capabilities seem to be most pronounced in awake humans. Here we assess the experience of volition across different states of consciousness: 10 frequent lucid dreamers rated different aspects of volition according to the Volitional Components Questionnaire for phases of normal dreaming, lucid dreaming, and wakefulness. Overall, experienced volition was comparable for lucid dreaming and wakefulness, and rated significantly higher for both states compared to non-lucid dreaming. However, three subscales showed specific differences across states of consciousness: planning ability was most pronounced during wakefulness, intention enactment most pronounced during lucid dreaming, and self-determination most pronounced during both wakefulness and lucid dreaming. Our data confirm the multifaceted nature of consciousness: different higher-order aspects of consciousness are differentially expressed across different conscious states.

Polycystic Ovary Syndrome: Update on Treatment Options and Treatment Considerations for the Future

OpenAIRE

Kristen A. Farrell-Turner

2011-01-01

Polycystic ovary syndrome is an endocrine disorder characterized by insulin resistance, hyperandrogenemia, obesity, and inflammation, and is the most common cause of infertility. Women with PCOS are at higher risk than non-PCOS women for diabetes, cardiovascular disease, endometrial cancer, and psychiatric disorders. Because many abnormalities present in PCOS and symptoms vary considerably among PCOS women, treatment is guided by presentation and does not consist of simply one modality. Often...

A new genus and new species of Philippine stick insects (Insecta: Phasmatodea) and phylogenetic considerations.

Science.gov (United States)

Gottardo, Marco

2011-07-01

Based on characters of both sexes, a new genus and species of the basal euphasmatodean lineage Aschiphasmatidae is described and figured from the Philippines. Dallaiphasma eximius gen. et sp. n. displays interesting features for the group, including: a cone-shaped vertex, which is notably raised above the pronotum; the tibial area apicalis represented by a depressed membranous posterior lateral region, and a strongly sclerotized central apical region; the euplantulae consisting of smooth-type attachment pads; the pretarsal claws pectination reduced to minute denticulations; and the well-differentiated boundary between the metanotum and the first abdominal tergum. The phylogenetic information content of the new findings is discussed. Furthermore, as a result of this study, the Aschiphasmatidae are newly recorded from Mindoro island, and now include five genera and six species of the Philippines. Copyright © 2011 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Tree species richness, diversity, and regeneration status in different oak (Quercus spp. dominated forests of Garhwal Himalaya, India

Directory of Open Access Journals (Sweden)

Sushma Singh

2016-09-01

Full Text Available Himalayan forests are dominated by different species of oaks (Quercus spp. at different altitudes. These oaks are intimately linked with hill agriculture as they protect soil fertility, watershed, and local biodiversity. They also play an important role in maintaining ecosystem stability. This work was carried out to study the diversity and regeneration status of some oak forests in Garhwal Himalaya, India. A total of 18 tree species belonging to 16 genera and 12 families were reported from the study area. Species richness varied for trees (4–7, saplings (3–10, and seedlings (2–6. Seedling and sapling densities (Ind/ha varied between 1,376 Ind/ha and 9,600 Ind/ha and 167 Ind/ha and 1,296 Ind/ha, respectively. Species diversity varied from 1.27 to 1.86 (trees, from 0.93 to 3.18 (saplings, and from 0.68 to 2.26 (seedlings. Total basal area (m2/ha of trees and saplings was 2.2–87.07 m2/ha and 0.20–2.24 m2/ha, respectively, whereas that of seedlings varied from 299 cm2/ha to 8,177 cm2/ha. Maximum tree species (20–80% had “good” regeneration. Quercus floribunda, the dominant tree species in the study area, showed “poor” regeneration, which is a matter of concern, and therefore, proper management and conservation strategies need to be developed for maintenance and sustainability of this oak species along with other tree species that show poor or no regeneration.

Bioacoustic investigations and taxonomic considerations on the Cicadetta montana species complex (Homoptera: Cicadoidea: Tibicinidae

Directory of Open Access Journals (Sweden)

Matija Gogala

2004-06-01

Full Text Available Recent bioacoustic investigations have shown that Cicadetta montana Scopoli 1772 is a complex of morphologically similar sister species that are best characterized by their song patterns. At the type locality of C. montana, only mountain cicadas with simple, long lasting song phrases were heard, recorded and collected. Therefore, we have good reasons to suggest that this type of song is characteristic for C. montana s. str. Boulard described a song of C. montana from France with phrases composed of a long and a short echeme; this type of song is characteristic for cicadas morphologically corresponding to C. montana var. brevipennis Fieber 1876; we suggest to raise this taxon to species level. On the basis of specific song, Puissant and Boulard described C. cerdaniensis from Pyrénées. A similar case was the discovery and description of C. montana macedonica Schedl 1999 from Macedonia; since these Macedonian cicadas are sympatric with at least two other cryptic species in the C. montana group and molecular investigations showed substantial genetic differences between C. macedonica and C. montana or C. brevipennis, we conclude that this taxon should also be raised to species level. Songs of closely related C. podolica and Korean mountain cicada are presented as well.Pesquisas recentes de bioacústica mostraram que Cicadetta montana Scopoli 1772 é um complexo de espécie-irmãs morfologicamente semelhantes e melhor caracterizadas por seus padrões de canto. Na localidade-tipo de C. montana somente cigarras serranas de longas frases de canto foram ouvidas, gravadas e coletadas. Portanto, temos boas razões para propor este tipo de canto como característico de C. montana s. str. Boulard descreveu um canto de C. montana da França com frases compostas de uma estridulação longa e uma curta; este tipo de canto é característico das cigarras correspondendo morfologicamente a C. montana var. brevipennis Fieber 1876; sugerimos elevar este táxon ao n

Restoration of heterogeneous disturbance regimes for the preservation of endangered species

Science.gov (United States)

Steven D. Warren; Reiner Buttner

2014-01-01

Disturbance is a natural component of ecosystems. All species, including threatened and endangered species, evolved in the presence of, and are adapted to natural disturbance regimes that vary in the kind, frequency, severity, and duration of disturbance. We investigated the relationship between the level of visible soil disturbance and the density of four endangered...

Reliable Memory Feedback Design for a Class of Nonlinear Fuzzy Systems with Time-varying Delay

Institute of Scientific and Technical Information of China (English)

You-Qing Wang; Dong-Hua Zhou; Li-Heng Liu

2007-01-01

This paper is concerned with the robust reliable memory controller design for a class of fuzzy uncertain systems with time-varying delay. The system under consideration is more general than those in other existent works. The controller, which is dependent on the magnitudes and derivative of the delay, is proposed in terms of linear matrix inequality (LMI). The closed-loop system is asymptotically stable for all admissible uncertainties as well as actuator faults. A numerical example is presented for illustration.

Corticosterone profiles in northern cardinals (Cardinalis cardinalis): Do levels vary through life history stages?

Science.gov (United States)

Duckworth, Benjamin M; Jawor, Jodie M

2018-04-17

As animals move through life history stages, energy requirements for each stage will vary. Both daily and annual variation in the glucocoriticoid hormones (specifically corticosterone, or CORT, in birds) helps provide the variable energy needed through life history stages. In many bird species, CORT is higher in the breeding season when energy demands can be quite high and is often lower in the non-breeding season. Additionally, CORT has a role to play in the response to stressful stimuli and the level to which CORT is elevated following stressful events can vary through the annual cycle as well. Here we report on baseline and stress-induced CORT levels in both sexes of northern cardinals, Cardinalis cardinalis, a non-migrating, year-round territorial species across life history stages. Corticosterone is overall higher in the non-breeding season than the breeding season in both sexes. Males tend to have higher levels of stress-induced CORT than females, although the observed patterns are complex. Our findings differ from one of the more common profile reported in songbirds where breeding season CORT tends to be higher than non-breeding levels. A strong influence may be the prolonged breeding season seen in cardinals; lower levels of CORT during breeding may guard against adverse maternal effects, interruptions in breeding behaviors, or egg production. Additional investigation of species with similar ecologies to northern cardinals, and more populations of cardinals, may show that annual glucocorticoid profiles are more labile than previously appreciated. Copyright © 2018 Elsevier Inc. All rights reserved.

Species traits and their non-additive interactions control the water economy of bryophyte cushions.

NARCIS (Netherlands)

Michel, P.; Lee, W.G.; During, H.J.; Cornelissen, J.H.C.; van der Putten, W.H.

2012-01-01

1. Ecological processes in mixed-species assemblages are not always an additive function of those in monocultures. In areas with high ground cover of bryophytes, renowned for their considerable water retention capacity, non-additive interactions in mixed-species cushions could play a key role in the

Assessing species saturation: conceptual and methodological challenges.

Science.gov (United States)

Olivares, Ingrid; Karger, Dirk N; Kessler, Michael

2018-05-07

Is there a maximum number of species that can coexist? Intuitively, we assume an upper limit to the number of species in a given assemblage, or that a lineage can produce, but defining and testing this limit has proven problematic. Herein, we first outline seven general challenges of studies on species saturation, most of which are independent of the actual method used to assess saturation. Among these are the challenge of defining saturation conceptually and operationally, the importance of setting an appropriate referential system, and the need to discriminate among patterns, processes and mechanisms. Second, we list and discuss the methodological approaches that have been used to study species saturation. These approaches vary in time and spatial scales, and in the variables and assumptions needed to assess saturation. We argue that assessing species saturation is possible, but that many studies conducted to date have conceptual and methodological flaws that prevent us from currently attaining a good idea of the occurrence of species saturation. © 2018 Cambridge Philosophical Society.

Traits related to species persistence and dispersal explain changes in plant communities subjected to habitat loss

DEFF Research Database (Denmark)

Marini, Lorenzo; Bruun, Hans Henrik; Heikkinen, Risto

2012-01-01

Aim Habitat fragmentation is a major driver of biodiversity loss but it is insufficiently known how much its effects vary among species with different life-history traits; especially in plant communities, the understanding of the role of traits related to species persistence and dispersal in dete...... rural landscapes in NW Europe, mitigating the spatial isolation of remaining grasslands should be accompanied by restoration measures aimed at improving habitat quality for low competitors, abiotically dispersed and perennial, clonal species.......Aim Habitat fragmentation is a major driver of biodiversity loss but it is insufficiently known how much its effects vary among species with different life-history traits; especially in plant communities, the understanding of the role of traits related to species persistence and dispersal...... in determining dynamics of species communities in fragmented landscapes is still limited. The primary aim of this study was to test how plant traits related to persistence and dispersal and their interactions modify plant species vulnerability to decreasing habitat area and increasing isolation. Location Five...

Density-dependent seedling mortality varies with light availability and species abundance in wet and dry Hawaiian forests

Science.gov (United States)

Faith Inman-Narahari; Rebecca Ostertag; Stephen P. Hubbell; Christian P. Giardina; Susan Cordell; Lawren Sack; Andrew MacDougall

2016-01-01

Conspecific density may contribute to patterns of species assembly through negative density dependence (NDD) as predicted by the Janzen-Connell hypothesis, or through facilitation (positive density dependence; PDD). Conspecific density effects are expected to be more negative in darker and wetter environments due to higher pathogen abundance and...

Effects of climate-induced increases in summer drought on riparian plant species : a meta-analysis

NARCIS (Netherlands)

Garssen, Annemarie G.; Verhoeven, Jos T. A.; Soons, Merel B.

Frequency and duration of summer droughts are predicted to increase in the near future in many parts of the world, with considerable anticipated effects on riparian plant community composition and species richness. Riparian plant communities along lowland streams are characterised by high species

Off-gas considerations for a vitrification plant in the republic of Korea

International Nuclear Information System (INIS)

Chun, Ung Kyung; Park, Jong Kil; Yang, Kyung Hwa; Song, Myung Jae

1997-01-01

The Republic of Korea is in the process of preparing for its first ever vitrification plant to handle low and intermediate-level radioactive waste from her pressurized water reactors (PWRs). KEPRI, in coordination with her partners, will design, construct, and erect a pilot plant using data from the orientation tests. The pilot plant will be the basis for the development of the final objective, the establishment of an industrial scale vitrification installation in the Republic of Korea. Throughout these projects, the major goal is to minimize the harmful effects of the final waste form to the environment. The gaseous effluents emissions from the facility will need to be managed to meet the environmental regulations concerning gaseous releases into the environment of the Republic of Korea. The focus of this paper is on the considerations for the treatment of the off-gas for a low and intermediate-level radioactive waste treatment vitrification installation in the Republic of Korea. Off-gas considerations will span a wide-range of areas such as waste characteristics, thermal treatment systems, off-gas regulations, off-gas characteristics, assessment of air pollution control devices, systems assessments, numerical modelling, economics etc. Off-gas regulations in Korea are becoming tighter and will likely change from year to year. In terms of both off-gas treatment equipment performance and public protection, the amount and nature (e.g. chemical behavior and morphology) of the species are important. The emissions may be classified as toxic metals, radionuclides, hydrocarbons, particulate matter, and acid gases. Air pollution control technologies are generally classified as wet or dry technologies covering over 40 different air pollution control devices (APCDs) with varying removal efficiencies for the different types of off-gas. In general, the state of the art systems for vitrification technologies incorporate the basic functions such as further oxidation of products

Ethical Considerations of Preclinical Testing

Directory of Open Access Journals (Sweden)

Allen Goldenthal

2015-12-01

Full Text Available The numbers of animal tests being conducted are on a sharp incline.  Much of this increase is directly due to our ability to generate transgenic models and knock-outs, thereby increasing the validity of the animal model but not necessarily correlating directly with any translational medical benefits to the human counterpart.  In spite of our best efforts, there still exist species differences that prevent the application directly from animal to human, and in some examples having a completely different and adverse effect from that seen in the animal model. There are several ways in which we can improve the opportunity for a positive test outcome and at the same time reduce the animal usage which is associated with our current animal testing practices. The benefit of the 3R’s is that they encourage us not only to avoid wastage of life but that they require us to provide considerable foresight and extrapolated thought before directly engaging in the preclinical testing phase.

Seed Removal Increased by Scramble Competition with an Invasive Species.

Science.gov (United States)

Minor, Rebecca L; Koprowski, John L

2015-01-01

Competition for seeds has a major influence on the evolution of granivores and the plants on which they rely. The complexity of interactions and coevolutionary relationships vary across forest types. The introduction of non-native granivores has considerable potential to alter seed dispersal dynamics. Non-native species are a major cause of endangerment for native species, but the mechanisms are often unclear. As biological invasions continue to rise, it is important to understand mechanisms to build up strategies to mitigate the threat. Our field experiment quantified the impact of introduced Abert's squirrels (Sciurus aberti) on rates of seed removal within the range of critically endangered Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis), which consumes similar foods. In the presence of invasive Abert's squirrels, the time cones were removed was faster than when the invasive was excluded, accounting for a median removal time of cones available to red and Abert's squirrels that is 32.8% less than that of cones available only to the rare native red squirrels. Moreover, in the presence of Abert's squirrels, removal rates are higher at great distance from a territorial red squirrel larderhoard and in more open portions of the forest, which suggests differential patterns of seed dispersal. The impact on food availability as a result of cone removal by Abert's squirrels suggests the potential of food competition as a mechanism of endangerment for the Mount Graham red squirrel. Furthermore, the magnitude and differential spatial patterns of seed removal suggest that non-native granivores may have impacts on forest regeneration and structure.

Seed Removal Increased by Scramble Competition with an Invasive Species.

Directory of Open Access Journals (Sweden)

Rebecca L Minor

Full Text Available Competition for seeds has a major influence on the evolution of granivores and the plants on which they rely. The complexity of interactions and coevolutionary relationships vary across forest types. The introduction of non-native granivores has considerable potential to alter seed dispersal dynamics. Non-native species are a major cause of endangerment for native species, but the mechanisms are often unclear. As biological invasions continue to rise, it is important to understand mechanisms to build up strategies to mitigate the threat. Our field experiment quantified the impact of introduced Abert's squirrels (Sciurus aberti on rates of seed removal within the range of critically endangered Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis, which consumes similar foods. In the presence of invasive Abert's squirrels, the time cones were removed was faster than when the invasive was excluded, accounting for a median removal time of cones available to red and Abert's squirrels that is 32.8% less than that of cones available only to the rare native red squirrels. Moreover, in the presence of Abert's squirrels, removal rates are higher at great distance from a territorial red squirrel larderhoard and in more open portions of the forest, which suggests differential patterns of seed dispersal. The impact on food availability as a result of cone removal by Abert's squirrels suggests the potential of food competition as a mechanism of endangerment for the Mount Graham red squirrel. Furthermore, the magnitude and differential spatial patterns of seed removal suggest that non-native granivores may have impacts on forest regeneration and structure.

Phylogenetic and Phylogenomic Definition of Rhizopus Species

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Andrii P. Gryganskyi

2018-06-01

Full Text Available Phylogenomic approaches have the potential to improve confidence about the inter-relationships of species in the order Mucorales within the fungal tree of life. Rhizopus species are especially important as plant and animal pathogens and bioindustrial fermenters for food and metabolite production. A dataset of 192 orthologous genes was used to construct a phylogenetic tree of 21 Rhizopus strains, classified into four species isolated from habitats of industrial, medical and environmental importance. The phylogeny indicates that the genus Rhizopus consists of three major clades, with R. microsporus as the basal species and the sister lineage to R. stolonifer and two closely related species R. arrhizus and R. delemar. A comparative analysis of the mating type locus across Rhizopus reveals that its structure is flexible even between different species in the same genus, but shows similarities between Rhizopus and other mucoralean fungi. The topology of single-gene phylogenies built for two genes involved in mating is similar to the phylogenomic tree. Comparison of the total length of the genome assemblies showed that genome size varies by as much as threefold within a species and is driven by changes in transposable element copy numbers and genome duplications.

The factors controlling species density in herbaceous plant communities: An assessment

Science.gov (United States)

Grace, J.B.

1999-01-01

This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects. Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of

Controversy in the allometric application of fixed- versus varying-exponent models: a statistical and mathematical perspective.

Science.gov (United States)

Tang, Huadong; Hussain, Azher; Leal, Mauricio; Fluhler, Eric; Mayersohn, Michael

2011-02-01

This commentary is a reply to a recent article by Mahmood commenting on the authors' article on the use of fixed-exponent allometry in predicting human clearance. The commentary discusses eight issues that are related to criticisms made in Mahmood's article and examines the controversies (fixed-exponent vs. varying-exponent allometry) from the perspective of statistics and mathematics. The key conclusion is that any allometric method, which is to establish a power function based on a limited number of animal species and to extrapolate the resulting power function to human values (varying-exponent allometry), is infused with fundamental statistical errors. Copyright © 2010 Wiley-Liss, Inc.

A Time-Varied Probabilistic ON/OFF Switching Algorithm for Cellular Networks

KAUST Repository

Rached, Nadhir B.; Ghazzai, Hakim; Kadri, Abdullah; Alouini, Mohamed-Slim

2018-01-01

In this letter, we develop a time-varied probabilistic on/off switching planning method for cellular networks to reduce their energy consumption. It consists in a risk-aware optimization approach that takes into consideration the randomness of the user profile associated with each base station (BS). The proposed approach jointly determines (i) the instants of time at which the current active BS configuration must be updated due to an increase or decrease of the network traffic load, and (ii) the set of minimum BSs to be activated to serve the networks’ subscribers. Probabilistic metrics modeling the traffic profile variation are developed to trigger this dynamic on/off switching operation. Selected simulation results are then performed to validate the proposed algorithm for different system parameters.

A Time-Varied Probabilistic ON/OFF Switching Algorithm for Cellular Networks

KAUST Repository

Rached, Nadhir B.

2018-01-11

In this letter, we develop a time-varied probabilistic on/off switching planning method for cellular networks to reduce their energy consumption. It consists in a risk-aware optimization approach that takes into consideration the randomness of the user profile associated with each base station (BS). The proposed approach jointly determines (i) the instants of time at which the current active BS configuration must be updated due to an increase or decrease of the network traffic load, and (ii) the set of minimum BSs to be activated to serve the networks’ subscribers. Probabilistic metrics modeling the traffic profile variation are developed to trigger this dynamic on/off switching operation. Selected simulation results are then performed to validate the proposed algorithm for different system parameters.

Qualitative research in multicultural psychology: philosophical underpinnings, popular approaches, and ethical considerations.

Science.gov (United States)

Ponterotto, Joseph G

2010-10-01

This article reviews the current and emerging status of qualitative research in psychology. The particular value of diverse philosophical paradigms and varied inquiry approaches to the advancement of psychology generally, and multicultural psychology specifically, is emphasized. Three specific qualitative inquiry approaches anchored in diverse philosophical research paradigms are highlighted: consensual qualitative research, grounded theory, and participatory action research. The article concludes by highlighting important ethical considerations in multicultural qualitative research. PsycINFO Database Record (c) 2010 APA, all rights reserved.

Epibiotic Diatoms Are Universally Present on All Sea Turtle Species

Science.gov (United States)

Majewska, Roksana; Lazo-Wasem, Eric A.; Nel, Ronel; Paladino, Frank V.; Rojas, Lourdes; Zardus, John D.; Pinou, Theodora

2016-01-01

The macro-epibiotic communities of sea turtles have been subject to growing interest in recent years, yet their micro-epibiotic counterparts are almost entirely unknown. Here, we provide the first evidence that diatoms are epibionts for all seven extant species of sea turtle. Using Scanning Electron Microscopy, we inspected superficial carapace or skin samples from a single representative of each turtle species. We distinguished 18 diatom taxa from these seven individuals, with each sea turtle species hosting at least two diatom taxa. We recommend that future research is undertaken to confirm whether diatom communities vary between sea turtle species and whether these diatom taxa are facultative or obligate commensals. PMID:27257972

Pollinator-mediated interactions in experimental arrays vary with neighbor identity.

Science.gov (United States)

Ha, Melissa K; Ivey, Christopher T

2017-02-01

Local ecological conditions influence the impact of species interactions on evolution and community structure. We investigated whether pollinator-mediated interactions between coflowering plants vary with plant density, coflowering neighbor identity, and flowering season. We conducted a field experiment in which flowering time and floral neighborhood were manipulated in a factorial design. Early- and late-flowering Clarkia unguiculata plants were placed into arrays with C. biloba neighbors, noncongeneric neighbors, additional conspecific plants, or no additional plants as a density control. We compared whole-plant pollen limitation of seed set, pollinator behavior, and pollen deposition among treatments. Interactions mediated by shared pollinators depended on the identity of the neighbor and possibly changed through time, although flowering-season comparisons were compromised by low early-season plant survival. Interactions with conspecific neighbors were likely competitive late in the season. Interactions with C. biloba appeared to involve facilitation or neutral interactions. Interactions with noncongeners were more consistently competitive. The community composition of pollinators varied among treatment combinations. Pollinator-mediated interactions involved competition and likely facilitation, depending on coflowering neighbor. Experimental manipulation helped to reveal context-dependent variation in indirect biotic interactions. © 2017 Botanical Society of America.

Disjunct populations of European vascular plant species keep the same climatic niches

DEFF Research Database (Denmark)

Wasof, Safaa; Lenoir, Jonathan; Aarrestad, Per Arild

2015-01-01

separated for thousands of years. Location: European Alps and Fennoscandia. Methods: Of the studied pool of 888 terrestrial vascular plant species occurring in both the Alps and Fennoscandia, we used two complementary approaches to test and quantify climatic-niche shifts for 31 species having strictly......Aim: Previous research on how climatic niches vary across species ranges has focused on a limited number of species, mostly invasive, and has not, to date, been very conclusive. Here we assess the degree of niche conservatism between distant populations of native alpine plant species that have been...... to be largely valid for arctic-alpine plants....

Environmental radiation protection of non-human vertebrate species: considerations for environmental monitoring and assessment in Canada

International Nuclear Information System (INIS)

MacDonald, C.R.

1996-01-01

The risk to non-human species from activities associated with the nuclear fuel waste cycle is coming under increased scrutiny from the public and regulators. In the past, protection of the environment was assumed to be an outcome of the protection of humans living in the same area. Thus it was assumed that if nuclides were maintained at low enough levels in water, air and soil to protect humans, then plants and animals inhabiting the same area would be protected. This approach of relying on humans as a sensitive indicator implicitly protects all species, at least at the population level. To adequately predict exposure and response in wild communities requires a detailed knowledge of the ecosystem under study and a method of predicting both the transfer of nuclides to individual species and the consequence of exposure. Detailed environmental, or ecological, risk estimation requires information on the normal levels of radiation and general physiological stress in the exposed group, an estimate of the additional radiation exposure from all pathways and a prediction of the consequences of the total exposure. The purpose of this paper is to review these requirements in the context of ecological radiation protection in the Canadian environment using examples of birds and mammals from the Canadian shield. Our goal is to develop methods which provide better estimates of potential risk to wild animals

Numerical analysis of a PCM thermal storage system with varying wall temperature

International Nuclear Information System (INIS)

Halawa, E.; Bruno, F.; Saman, W.

2005-01-01

Numerical analysis of melting and freezing of a PCM thermal storage unit (TSU) with varying wall temperature is presented. The TSU under analysis consists of several layers of thin slabs of a PCM subjected to convective boundary conditions where air flows between the slabs. The model employed takes into account the variations in wall temperature along the direction of air flow as well as the sensible heat. The paper discusses typical characteristics of the melting/freezing of PCM slabs in an air stream and presents some results of the numerical simulation in terms of air outlet temperatures and heat transfer rates during the whole periods of melting and freezing. Considerations in the design of the TSU are also given

Invasive species in southern Nevada [Chapter 4

Science.gov (United States)

Mathew L. Brooks; Steven M. Ostoja; Jeanne C. Chambers

2013-01-01

Southern Nevada contains a wide range of topographies, elevations, and climatic zones emblematic of its position at the ecotone between the Mojave Desert, Great Basin, and Colorado Plateau ecoregions. These varied environmental conditions support a high degree of biological diversity (Chapter 1), but they also provide opportunities for a wide range of invasive species...

Bioethical Considerations of Advancing the Application of Marine Biotechnology and Aquaculture.

Science.gov (United States)

Harrell, Reginal M

2017-06-24

Normative ethical considerations of growth of the marine biotechnology and aquaculture disciplines in biopharming, food production, and marine products commercialization from a bioethical perspective have been limited. This paucity of information begs the question of what constitutes a bioethical approach (i.e., respect for individuals or autonomy; beneficence, nonmaleficence, and justice) to marine biotechnology and aquaculture, and whether it is one that is appropriate for consideration. Currently, thoughtful discussion on the bioethical implications of use, development, and commercialization of marine organisms or their products, as well as potential environmental effects, defaults to human biomedicine as a model. One must question the validity of using human bioethical principlism moral norms for appropriating a responsible marine biotechnology and aquaculture ethic. When considering potential impacts within these disciplines, deference must be given to differing value systems in order to find common ground to advance knowledge and avoid emotive impasses that can hinder the science and its application. The import of bioethical considerations when conducting research and/or production is discussed. This discussion is directed toward applying bioethical principles toward technology used for food, biomedical development (e.g., biopharming), or as model species for advancement of knowledge for human diseases.

Bioethical Considerations of Advancing the Application of Marine Biotechnology and Aquaculture

Directory of Open Access Journals (Sweden)

Reginal M. Harrell

2017-06-01

Full Text Available Normative ethical considerations of growth of the marine biotechnology and aquaculture disciplines in biopharming, food production, and marine products commercialization from a bioethical perspective have been limited. This paucity of information begs the question of what constitutes a bioethical approach (i.e., respect for individuals or autonomy; beneficence, nonmaleficence, and justice to marine biotechnology and aquaculture, and whether it is one that is appropriate for consideration. Currently, thoughtful discussion on the bioethical implications of use, development, and commercialization of marine organisms or their products, as well as potential environmental effects, defaults to human biomedicine as a model. One must question the validity of using human bioethical principlism moral norms for appropriating a responsible marine biotechnology and aquaculture ethic. When considering potential impacts within these disciplines, deference must be given to differing value systems in order to find common ground to advance knowledge and avoid emotive impasses that can hinder the science and its application. The import of bioethical considerations when conducting research and/or production is discussed. This discussion is directed toward applying bioethical principles toward technology used for food, biomedical development (e.g., biopharming, or as model species for advancement of knowledge for human diseases.

Consideration on thermodynamic data for predicting solubility and chemical species of elements in groundwater. Part 2: Np, Pu

International Nuclear Information System (INIS)

Yamaguchi, Tetsuji

2000-11-01

The solubility determines the release of a radionuclide from waste form and is used as a source term in radionuclide migration analysis in performance assessment of radioactive waste repository. Complexations of the radionuclide by ligands in groundwater affect the interaction between radionuclides and geologic media, thus affect their migration behavior. It is essential to estimate the solubility and to predict the chemical species for the radionuclide based on thermodynamic data. The thermodynamic data of aqueous species and compounds were reviewed and compiled for Np and Pu. Thermodynamic data were reviewed with emphasis on the hydrolysis and carbonate complexation that can dominate the speciation in groundwater. Thermodynamic data for other species were selected based on existing databases. Thermodynamic data for other important elements are under investigation, thus shown in an appendix for temporary use. (author)

Caloric content of leaves of five tree species from the riparian vegetation in a forest fragment from South Brazil

Directory of Open Access Journals (Sweden)

Leandro Fabrício Fiori

2015-09-01

Full Text Available Abstract Aim: The measurement of the caloric content evidences the amount of energy that remains in the leaf and that can be released to the aquatic trophic chain. We assessed the energy content of leaves from five riparian tree species of a forest fragment in south Brazil and analyzed whether leaf caloric content varied between leaf species and between seasons (dry and wet. The studied sites are located in Northwest of Paraná State, inside a Semi-Deciduous Forest fragment beside two headwater streams. Methods Sampling sites were located along the riparian vegetation of these two water bodies, and due to its proximity and absence of statistical differences of caloric values, analyzed as one compartment. Results Caloric content varied significantly among species and among all pairs of species, with exception of Nectandra cuspidata Ness and Calophyllum brasiliensis Cambess. Two species presented significant differences between seasons, Sloanea guianensis (Aubl. Ben and Calophyllum brasiliensis Cambess. Conclusions The absence of significant seasonal differences of energy content for some species may be due to the characteristics of the tropical forest, in which temperature did not varied dramatically between seasons. However, the energy differed between species and seasons for some species, emphasizing the necessity of a preliminary inspection of energy content, before tracing energy fluxes instead of using a single value to all species from riparian vegetation.

Finite-Time Reentry Attitude Control Using Time-Varying Sliding Mode and Disturbance Observer

Directory of Open Access Journals (Sweden)

Xuzhong Wu

2015-01-01

Full Text Available This paper presents the finite-time attitude control problem for reentry vehicle with redundant actuators in consideration of planet uncertainties and external disturbances. Firstly, feedback linearization technique is used to cancel the nonlinearities of equations of motion to construct a basic mode for attitude controller. Secondly, two kinds of time-varying sliding mode control methods with disturbance observer are integrated with the basic mode in order to enhance the control performance and system robustness. One method is designed based on boundary layer technique and the other is a novel second-order sliding model control method. The finite-time stability analyses of both resultant closed-loop systems are carried out. Furthermore, after attitude controller produces the torque commands, an optimization control allocation approach is introduced to allocate them into aerodynamic surface deflections and on-off reaction control system thrusts. Finally, the numerical simulation results demonstrate that both of the time-varying sliding mode control methods are robust to uncertainties and disturbances without chattering phenomenon. Moreover, the proposed second-order sliding mode control method possesses better control accuracy.

Floral reward in Ranunculaceae species

Directory of Open Access Journals (Sweden)

Bożena Denisow

2016-04-01

Full Text Available Floral reward is important in ecological and evolutionary perspectives and essential in pollination biology. For example, floral traits, nectar and pollen features are essential for understanding the functional ecology, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant–pollinator interactions. We believe to present a synthetic description in the field of floral reward in Ranunculaceae family important in pollination biology and indicating connections between ecological and evolutionary approaches. The links between insect visitors’ behaviour and floral reward type and characteristics exist. Ranunculaceae is a family of aboot 1700 species (aboot 60 genera, distributed worldwide, however the most abundant representatives are in temperate and cool regions of the northern and southern hemispheres. The flowers are usually radially symmetric (zygomorphic and bisexual, but in Aconitum, Aquilegia are bilaterally symmetric (zygomorphic. Most Ranunculaceae flowers offer no nectar, only pollen (e.g., Ranunculus, Adonis vernalis, Thalictrum, but numerous species create trophic niches for different wild pollinators (e.g. Osmia, Megachile, Bombus, Andrena (Denisow et al. 2008. Pollen is a source of protein, vitamins, mineral salts, organic acids and hormones, but the nutritional value varies greatly between different plant species. The pollen production can differ significantly between Ranunculacea species. The mass of pollen produced in anthers differ due to variations in the number of developed anthers. For example, interspecies differences are considerable, 49 anthers are noted in Aquilegia vulgaris, 70 anthers in Ranunculus lanuginosus, 120 in Adonis vernalis. A significant intra-species differences’ in the number of anthers are also noted (e.g. 41 to 61 in Aquilegia vulgaris, 23-45 in Ranunculus cassubicus. Pollen production can be up to 62 kg per ha for Ranunculus acer

Two new species of Hepatozoon (Apicomplexa: Hepatozoidae) parasitising species of Philothamnus (Ophidia: Colubridae) from South Africa.

Science.gov (United States)

Cook, Courtney Antonia; Netherlands, Edward Charles; As, Johann van; Jacobus Smit, Nico

2018-04-03

To date, only a few species of Hepatozoon Miller, 1908 have been described from amphibians and reptiles of South Africa, including two species from anuran hosts, three from saurians, one from chelonians, and two from ophidians. Hepatozoon bitis (Fantham, 1925) and Hepatozoon refringens (Sambon et Seligmann, 1907), parasitising Bitis arientans (Merrem) and Pseudoaspis cana (Linnaeus), respectively, were described in the early 1900s and since then there have been no further species of Hepatozoon described from snakes in South Africa. Blood smears, used in peripheral blood haemogregarine stage morphometrics, and whole blood used in molecular characterisation of haemogregarines were collected from the caudal vein of six snakes of three species, namely Philothamnus hoplogaster (Günther), Philothamnus semivariegatus (Smith) and Philothamnus natalensis natalensis (Smith). For comparison, a comprehensive table summarising available information on species of Hepatozoon from African snakes is presented. Haemogregarines found infecting the snakes from the present study were morphologically and molecularly different from any previously described from Africa and are thus here described as Hepatozoon angeladaviesae sp. n. and Hepatozoon cecilhoarei sp. n. Both haemogregarine species were observed to cause considerable dehaemoglobinisation of the host cell, in case of infection with H. angeladaviesae resulting in a characteristic peripheral undulation of the host cell membrane and karyorrhexis. To the authors' knowledge, these are the first haemogregarines parasitising snakes of the genus Philothamnus Smith described using both morphological and molecular characteristics in Africa.

The geography of demography: long-term demographic studies and species distribution models reveal a species border limited by adaptation.

Science.gov (United States)

Eckhart, V M; Geber, M A; Morris, W F; Fabio, E S; Tiffin, P; Moeller, D A

2011-10-01

Potential causes of species' geographic distribution limits fall into two broad classes: (1) limited adaptation across spatially variable environments and (2) limited opportunities to colonize unoccupied areas. Combining demographic studies, analyses of demographic responses to environmental variation, and species distribution models, we investigated the causes of range limits in a model system, the eastern border of the California annual plant Clarkia xantiana ssp. xantiana. Vital rates of 20 populations varied with growing season temperature and precipitation: fruit number and overwinter survival of 1-year-old seeds declined steeply, while current-year seed germination increased modestly along west-to-east gradients in decreasing temperature, decreasing mean precipitation, and increasing variation in precipitation. Long-term stochastic finite rate of increase, λ(s), exhibited a fourfold range and varied among geologic surface materials as well as with temperature and precipitation. Growth rate declined significantly toward the eastern border, falling below 1 in three of the five easternmost populations. Distribution models employing demographically important environmental variables predicted low habitat favorability beyond the eastern border. Models that filtered or weighted population presences by λ(s) predicted steeper eastward declines in favorability and assigned greater roles in setting the distribution to among-year variation in precipitation and to geologic surface material. These analyses reveal a species border likely set by limited adaptation to declining environmental quality.

Foliar phenolic compounds of ten wild species of Verbenacea as antioxidants and specific chemomarkers

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J. A. Ávila-Reyes

2017-06-01

Full Text Available Abstract The family Verbenaceae hosts important species used in traditional medicine of many countries. The taxonomic controversies concerning the specific delimitation of several of its species make it difficult to guarantee the botanical origin of herbal preparations based on species of this family. To contribute to the development of both specific chemomarkers and a quality control tool to authenticate the botanical origin of herbal preparations of Verbenacea species, we determined the foliar HPLC-DAD phenolic profiles and the antioxidant properties of 10 wild species of this family occurring in Mexico. The contents of phenols and flavonoids varied significantly among species. Priva mexicana showed the highest levels of total phenolics (53.4 mg g-1 dry tissue and Verbena carolina had the highest levels of flavonoids (17.89 mg g-1 dry tissue. Relevant antioxidant properties revealed by antiradical and reducing power were found for the analyzed species. These properties varied significantly in a species-dependent manner. The phenolic compounds accumulated were flavones and phenolic acids. Flavones were the only type of flavonoids found. The results of a cluster analysis showed that the compounds were accumulated in species-specific profiles. The phenolic profiles are proposed as valuable chemomarkers that can become a useful tool for the quality control concerning the botanical origin of herbal medicinal preparations based on the species analyzed. In addition, phenolic profiles could contribute importantly to solve the taxonomic controversies concerning species delimitation in the family Verbenaceae.

Variation in nesting behavior of eight species of spider mites, Stigmaeopsis having sociality

Science.gov (United States)

Saito, Yutaka; Zhang, Yan-Xuan; Mori, Kotaro; Ito, Katsura; Sato, Yukie; Chittenden, Anthony R.; Lin, Jian-Zhen; Chae, Younghae; Sakagami, Takane; Sahara, Ken

2016-10-01

Nesting behavior is considered to be an important element of social living in animals. The spider mites belonging to the genus Stigmaeopsis spend their lives within nests produced from silk threads. Several of these species show cooperative sociality, while the others are subsocial. In order to identify the origins of this social behavior, comparisons of nest sizes, nesting behaviors (making nests continuously or separately), and their associated traits (fecal deposition patterns) were made for eight cogeneric Stigmaeopsis species showing various levels of social development. All of these species inhabit bamboo plants (Poaceae). We initially addressed the proximate factor of nest size variation. The variation in nest size of the eight species corresponded well with the variation in dorsal seta sc1 length, suggesting that nest size variation among species may have a genetic basis. The time spent within a nest (nest duration) increased with nest size on the respective host plants. Nest arrangement patterns varied among species showing different sized nests: Large nest builders continuously extended their nests, while middle and small nest-building species built new separate nests, which resulted in different social interaction times among species, and is thought to be closely related to social development. Fecal deposition behaviors also varied among Stigmaeopsis species, suggesting diversity in anti-predatory adaptations. Finally, we discuss how the variation in sociality observed within this genus is likely the result of nest size variation that initially evolved as anti-predator strategies.

Direct seeding woody species for restoration of bottomlands

Science.gov (United States)

Twedt, D.J.; Connor, Kristina F

2006-01-01

I direct seeded (broadcast) seeds of 39 species of trees and shrubs using an ATV-mounted rotary spreader to initiate restoration of bottomland forest on retired agricultural sites. Four sites were planted during February, 2000, and 13 additional sites were planted during April and May, 2001. After two growing seasons, stem density of direct-seeded species varied greatly among study plots (range = 0 to 888 stems/ha) but averaged only 110 stems/ha. I recommend that future efforts at direct seeding focus on seven shrub species (Amorpha fruticosa L., Cephalanthus occidentalis L., Cornus spp., Crataegus spp., Ilex decidua Walt., Morus rubra L., and Prunus spp.) and seven tree species (Celtis laevigata Willd., Diospyros virginiana L., Fraxinus spp., Gleditsia triacanthos L., Robinia pseudoacacia L., Taxodium distichum (L.) Rich, and Ulmus spp.) that successfully established in these trials.

Dust retaining properties of leaves of some tree species

Energy Technology Data Exchange (ETDEWEB)

Gusev, M I

1960-05-01

A study was made in Tashkent, Russia of the dust-retaining power of leaves of several tree species. Investigations were made in a park where these tree species were growing in close proximity, exposed to the effects of dust from the main city street and from the highway passing through the park. Observations on the dust-retaining power of leaves were made mostly during the summer and fall months. The dust-retaining power of leaves of different tree species varied with the dust concentration in the air. In the summer and fall when rains are scarce a steady accumulation of dust was observed on the surface of the leaves. 1 table.

Deposition and solubility of airborne metals to four plant species grown at varying distances from two heavily trafficked roads in London

International Nuclear Information System (INIS)

Peachey, C.J.; Sinnett, D.; Wilkinson, M.; Morgan, G.W.; Freer-Smith, P.H.; Hutchings, T.R.

2009-01-01

In urban areas, a highly variable mixture of pollutants is deposited as particulate matter. The concentration and bioavailability of individual pollutants within particles need to be characterised to ascertain the risks to ecological receptors. This study, carried out at two urban parks, measured the deposition and water-solubility of metals to four species common to UK urban areas. Foliar Cd, Cr, Cu, Fe, Ni, Pb and Zn concentrations were elevated in at least one species compared with those from a rural control site. Concentrations were, however, only affected by distance to road in nettle and, to a lesser extent, birch leaves. Greater concentrations of metal were observed in these species compared to cypress and maple possibly due to differences in plant morphology and leaf surfaces. Solubility appeared to be linked to the size fraction and, therefore, origin of the metal with those present predominantly in the coarse fraction exhibiting low solubility. - High density traffic resulted in elevated metal concentrations on vegetation, which were related to distance from road and plant species.

Deposition and solubility of airborne metals to four plant species grown at varying distances from two heavily trafficked roads in London

Energy Technology Data Exchange (ETDEWEB)

Peachey, C.J. [Forest Research, Centre for Forestry and Climate Change, Alice Holt Lodge, Farnham, Surrey GU10 4LH (United Kingdom); Sinnett, D., E-mail: danielle.sinnett@forestry.gsi.gov.u [Forest Research, Centre for Forestry and Climate Change, Alice Holt Lodge, Farnham, Surrey GU10 4LH (United Kingdom); Wilkinson, M., E-mail: matthew.wilkinson@forestry.gsi.gov.u [Forest Research, Centre for Forestry and Climate Change, Alice Holt Lodge, Farnham, Surrey GU10 4LH (United Kingdom); Morgan, G.W., E-mail: geoff.morgan@forestry.gsi.gov.u [Forest Research, Centre for Forestry and Climate Change, Alice Holt Lodge, Farnham, Surrey GU10 4LH (United Kingdom); Freer-Smith, P.H., E-mail: peter.freer-smith@forestry.gsi.gov.u [Forest Research, Centre for Forestry and Climate Change, Alice Holt Lodge, Farnham, Surrey GU10 4LH (United Kingdom); Hutchings, T.R., E-mail: tony.hutchings@forestry.gsi.gov.u [Forest Research, Centre for Forestry and Climate Change, Alice Holt Lodge, Farnham, Surrey GU10 4LH (United Kingdom)

2009-08-15

In urban areas, a highly variable mixture of pollutants is deposited as particulate matter. The concentration and bioavailability of individual pollutants within particles need to be characterised to ascertain the risks to ecological receptors. This study, carried out at two urban parks, measured the deposition and water-solubility of metals to four species common to UK urban areas. Foliar Cd, Cr, Cu, Fe, Ni, Pb and Zn concentrations were elevated in at least one species compared with those from a rural control site. Concentrations were, however, only affected by distance to road in nettle and, to a lesser extent, birch leaves. Greater concentrations of metal were observed in these species compared to cypress and maple possibly due to differences in plant morphology and leaf surfaces. Solubility appeared to be linked to the size fraction and, therefore, origin of the metal with those present predominantly in the coarse fraction exhibiting low solubility. - High density traffic resulted in elevated metal concentrations on vegetation, which were related to distance from road and plant species.

Radial variation in fiber length of some lesser used wood species in ...

African Journals Online (AJOL)

Variations in fibre length of ten lesser used wood species were investigated. The mean fibre length varied from 1.07mm in Lannea acida to 2.41mm in Sterculia setigera. Four patterns of within tree radial variations in fibre length were observed in the studied species. In pattern one, fibre length increased from the pith to the ...

Phytoremdiation Species And Their Modification Under By Weed Varying Climatic Condition A Changing Scenario

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Anita Singh

2015-08-01

Full Text Available Abstract The major reasons for environmental contamination are population explosion increase in industrial and other urban activities. One of the consequent effect of these activities is heavy metal pollution. It is one of the serious issue to be discussed by the scientists and academicians that how to solve this problem to protect the environment. As heavy metals are non-biodegradable so they require effective cleanup technology. Most of the traditional methods such as excavation solidification and burial are very costly or they simply involve the isolation of the metals from contaminated sites. Among different technologies phytoremediation is best approach for removing metal contamination from environment. It involves plants to remove detoxify or immobilize metals from environment. Weed plants are found to be play very important role in metal remediation. They get affected by climatic variation which is also a consequent effect of environmental pollution. The physiology of plants as well as physiochemical properties of soil gets affected by varying climatic condition. Therefore the present review gives the information on metal remediation processes and how these process particularly phytoremediation by weed plants get affected by climatic changes.

MDGC-MS analysis of essential oils from Protium heptaphyllum (Aubl. and their antifungal activity against Candida specie

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M. MOBIN

Full Text Available ABSTRACT Protium heptaphyllum is found in the Amazon region, and in various Brazilian states and South American countries. Also Known as almecega, it produces an oil resin used in traditional medicine as analgesic, anti-inflammatory, cicatrizant and expectorant, it is rich in pentacyclic triterpenes and essential oil. The main objective of this study was to analyze the chemical composition of P. heptaphyllumresin (OEPh over different extraction times and to evaluate their antifungal activity against Candida species, obtained from gardeners with onychomycosis, using the disk diffusion method. The OEPh was obtained by hydrodistillation and analyzed by Multidimensional Gas Chromatography coupled with Mass Spectrometry (MDGC / MS. Candida species were obtained from lesions on the nails of horticulturist from a community garden in the city of Teresina, Piauí, Brazil. The antifungal activity in concentrations of 1000 µg/L, 500 µg/L and 250 µg/L, PROTOCOL M44-A2 (CLSI 2009 OEPh was tested. The main constituents identified were: l-limonene, α-terpineol, p-cineol, o-cymene and α-phellandrene, however, its composition varies significantly with extraction time. All species, except C. rugosa, were inhibited with halo (≥ 14 mm at 1000 μg / L. C. krusei is naturally resistant to the drug fluconazole, but when tested with OEPh the clinical species (case 9 demonstrated sensitivity in three dilutions (halo ≤ 10 ≥ 14 and the standard strain was inhibited at concentration of 1000 μg/Lg / L (halo 14mm. A similar situation also occurred with the standard strain of C. parapsilosis (halo ≥ 11mm. OEPh has considerable antifungal activity, which merits further investigation for alternative clinical applications, since this species is widely distributed in our community, and it presents good yields, and also has important therapeutic applications.

Epibiotic Diatoms Are Universally Present on All Sea Turtle Species.

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Nathan J Robinson

Full Text Available The macro-epibiotic communities of sea turtles have been subject to growing interest in recent years, yet their micro-epibiotic counterparts are almost entirely unknown. Here, we provide the first evidence that diatoms are epibionts for all seven extant species of sea turtle. Using Scanning Electron Microscopy, we inspected superficial carapace or skin samples from a single representative of each turtle species. We distinguished 18 diatom taxa from these seven individuals, with each sea turtle species hosting at least two diatom taxa. We recommend that future research is undertaken to confirm whether diatom communities vary between sea turtle species and whether these diatom taxa are facultative or obligate commensals.

Inter-species comparative analysis of components of soluble sugar concentration in fleshy fruits

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Zhanwu eDai

2016-05-01

Full Text Available The soluble sugar concentration of fleshy fruit is a key determinant of fleshy fruit quality. It affects directly the sweetness of fresh fruits and indirectly the properties of processed products (e.g. alcohol content in wine. Despite considerable divergence among species, soluble sugar accumulation in a fruit results from the complex interplay of three main processes, namely sugar import, sugar metabolism, and water dilution. Therefore, inter-species comparison would help to identify common and/or species-specific modes of regulation in sugar accumulation. For this purpose, a process-based mathematical framework was used to compare soluble sugar accumulation in three fruits: grape, tomato and peach. Representative datasets covering the time course of sugar accumulation during fruit development were collected. They encompassed 104 combinations of species (3, genotypes (32, and growing conditions (19 years and 16 nutrient and environmental treatments. At maturity, grape showed the highest soluble sugar concentrations (16.5-26.3 g /100 g FW, followed by peach (2.2 to 20 g /100 g FW and tomato (1.4 to 5 g /100 g FW. Main processes determining soluble sugar concentration were decomposed into sugar importation, metabolism and water dilution with the process-based analysis. Different regulation modes of soluble sugar concentration were then identified, showing either import-based, dilution-based, or import and dilution dual-based. Firstly, the higher soluble sugar concentration in grape than in tomato is a result of higher sugar importation. Secondly, the higher soluble sugar concentration in grape than in peach is due to a lower water dilution. The third mode of regulation is more complicated than the first two, with differences both in sugar importation and water dilution (grape vs cherry tomato; cherry tomato vs peach; peach vs tomato. On the other hand, carbon utilization for synthesis of non-soluble sugar compounds (namely metabolism was

Biochemical and physiological changes in Egyptian Nile fish subjected to varying levels of gamma irradiation

International Nuclear Information System (INIS)

Roushdy, H.M.; El-Kashef, H.S.; Imam, A.E.

1975-01-01

Radiation is nowadays to be considered as a new parameter in the ecology of water masses. Aquatic organisms, perhaps more than any other group of organisms, are directly exposed to radiation hazard and may be subjected to continuous low-level exposure from bottom material and from internal sources accumulated within their own bodies, originating partly from radionuclides released from nuclear facilities into the aquatic environment. In recent years, a large number of papers have been published on the uptake, concentration and release of radioactive material by aquatic organisms. However, radiation experiments on fish, a major source of food for human consumption, are still very rare and mostly restricted to studies on the effect of irradiation on eggs and larvae. Since the study of the radiation effect on living aquatic organisms, particularly fish, is important in connection with the problems of preserving water resources for the benefit of mankind, the work presented here has been done to ascertain the effect of varying dose-levels of gamma irradiation on two common Egyptian Nile fish species, the catfish Clarias lazera and the Tilapia nilotica. Investigations carried out on Clarias lazera involved blood and muscle analyses as well as growth rate measurements. The results obtained showed impaired haematological levels, changes in weight of muscle proteins and, chiefly, retardation in growth rate. Investigations carried out on Tilapia nilotica revealed changes in the activity of certain digestive enzyme systems, glucose level in blood and concentration of the glycogen store in liver and muscles. In discussing the results obtained the authors have taken the relevant literature into consideration. (author)

Ferromanganese nodule fauna in the Tropical North Pacific Ocean: Species richness, faunal cover and spatial distribution

Science.gov (United States)

Veillette, Julie; Sarrazin, Jozée; Gooday, Andrew J.; Galéron, Joëlle; Caprais, Jean-Claude; Vangriesheim, Annick; Étoubleau, Joël; Christian, James R.; Kim Juniper, S.

2007-11-01

The poorly known ferromanganese nodule fauna is a widespread hard substratum community in the deep sea that will be considerably impacted by large-scale nodule mining operations. The objective of this study was to analyze the spatial distribution of the fauna attached to nodules in the Clarion-Clipperton Fracture Zone at two scales; a regional scale that includes the east (14°N, 130°W) and the west (9°N, 150°W) zones and a local scale in which different geological facies (A, B, C and west) are recognizable. The fauna associated with 235 nodules was quantitatively described: 104 nodules from the east zone (15 of facies A, 50 of facies B and 39 of facies C) and 131 nodules from the west zone. Percent cover was used to quantify the extent of colonization at the time of sampling, for 42 species out of the 62 live species observed. Fauna covered up to 18% of exposed nodule surface with an average of about 3%. While species richness increased with exposed nodule surface, both at the regional and at the facies scales (except for facies A), total species density decreased (again except for facies A). When all nodules were included in the statistical analysis, there was no relation between faunal cover and exposed nodule surface. Nevertheless, faunal cover did decrease with exposed nodule surface for the east zone in general and for both facies B and C in particular. Species distributions among facies were significantly different but explained only a very small portion of the variance (˜5%). We identified two groups of associated species: a first group of two species and a second group of six species. The other species (34) were independently distributed, suggesting that species interactions play only a minor role in the spatial distribution of nodule fauna. The flux of particulate organic carbon to the bottom is the only major environmental factor considered to vary between the two zones within this study. We conclude that the higher species richness and higher

Redescription of the Advertisement Call of Five Species of Thoropa (Anura, Cycloramphidae), Including Recordings of Rare and Endangered Species.

Science.gov (United States)

Nunes-de-Almeida, Carlos H L; Assis, Clodoaldo L; Feio, Renato N; Toledo, Luís Felipe

2016-01-01

Frogs of the genus Thoropa comprise six endemic Brazilian species on the Eastern side of the country. Little is known about their natural history, especially about their acoustic communication. Therefore, aiming to provide an overview of their vocalizations, we analyzed and redescribed male advertisement calls of three living and two possibly extinct species. The smaller species, T. petropolitana and T. lutzi, produce simple calls (one single note) with a higher frequency range than the remaining larger ones. On the other hand, the larger species present complex calls, with more than one note: T. megatympanum calls have three notes, T. taophora calls have four notes, and T. miliaris calls varies from three to six notes. Population snout-vent length negatively correlated with peak of dominant frequency as expected. However, highlighted differences between two populations of T. lutzi, which could indicate need of further taxonomic evaluation of those lineages. Peculiar morphology, such as the absence of vocal sacs and slits, may have contributed to their call variation and highly banded frequency structure. If the observed population differences reflect species-level differences, T. lutzi may be classified as a critically endangered species, as T. petropolitana. Furthermore, we provided a suggestion to an unusual behavior in frogs: calling with the mouth open in the smaller species of the genus.

Morphology, Diet Composition, Distribution and Nesting Biology of Four Lark Species in Mongolia

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Galbadrakh Mainjargal

2013-12-01

Full Text Available We aimed to enhance existing knowledge of four lark species (Mongolian lark , Horned lark, Eurasian skylark, and Lesser short-toed lark, with respect to nesting biology, distribution, and diet, using long-term dataset collected during 2000–2012. Nest and egg measurements substantially varied among species. For pooled data across species, the clutch size averaged 3.72 ± 1.13 eggs and did not differ among larks. Body mass of nestlings increased signi fi cantly with age at weighing. Daily increase in body mass of lark nestlings ranged between 3.09 and 3.89 gram per day. Unsurprisingly, the majority of lark locations occurred in steppe ecosystems, followed by human created systems; whereas only 1.8% of the pooled locations across species were observed in forest ecosystem. Diet composition did not vary among species in the proportions of major food categories consumed. The most commonly occurring food items were invertebrates and frequently consumed were being beetles (e.g. Coleoptera: Carabidae, Scarabaeidae, and Curculionidae and grasshoppers (e.g. Orthoptera: Acrididae, and their occurrences accounted for 63.7% of insect related food items. Among the fi ve morphological traits we measured, there were signi fi cant differences in wing span, body mass, bill, and tarsus; however tail lengths did not differ across four species.

Effects of local adaptation and interspecific competition on species' responses to climate change.

Science.gov (United States)

Bocedi, Greta; Atkins, Katherine E; Liao, Jishan; Henry, Roslyn C; Travis, Justin M J; Hellmann, Jessica J

2013-09-01

Local adaptation and species interactions have been shown to affect geographic ranges; therefore, we need models of climate impact that include both factors. To identify possible dynamics of species when including these factors, we ran simulations of two competing species using an individual-based, coupled map-lattice model using a linear climatic gradient that varies across latitude and is warmed over time. Reproductive success is governed by an individual's adaptation to local climate as well as its location relative to global constraints. In exploratory experiments varying the strength of adaptation and competition, competition reduces genetic diversity and slows range change, although the two species can coexist in the absence of climate change and shift in the absence of competitors. We also found that one species can drive the other to extinction, sometimes long after climate change ends. Weak selection on local adaptation and poor dispersal ability also caused surfing of cooler-adapted phenotypes from the expanding margin backwards, causing loss of warmer-adapted phenotypes. Finally, geographic ranges can become disjointed, losing centrally-adapted genotypes. These initial results suggest that the interplay between local adaptation and interspecific competition can significantly influence species' responses to climate change, in a way that demands future research. © 2013 New York Academy of Sciences.

Evolutionary patterns of range size, abundance and species richness in Amazonian angiosperm trees

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Kyle Dexter

2016-09-01

Full Text Available Amazonian tree species vary enormously in their total abundance and range size, while Amazonian tree genera vary greatly in species richness. The drivers of this variation are not well understood. Here, we construct a phylogenetic hypothesis that represents half of Amazonian tree genera in order to contribute to explaining the variation. We find several clear, broad-scale patterns. Firstly, there is significant phylogenetic signal for all three characteristics; closely related genera tend to have similar numbers of species and similar mean range size and abundance. Additionally, the species richness of genera shows a significant, negative relationship with the mean range size and abundance of their constituent species. Our results suggest that phylogenetically correlated intrinsic factors, namely traits of the genera themselves, shape among lineage variation in range size, abundance and species richness. We postulate that tree stature may be one particularly relevant trait. However, other traits may also be relevant, and our study reinforces the need for ambitious compilations of trait data for Amazonian trees. In the meantime, our study shows how large-scale phylogenies can help to elucidate, and contribute to explaining, macroecological and macroevolutionary patterns in hyperdiverse, yet poorly understood regions like the Amazon Basin.

Species specific uptake of radio-labelled phytodetritus by benthic meiofauna from the Baltic Sea

NARCIS (Netherlands)

Ólafsson, E.; Modig, H.; Van de Bund, W.J.

1999-01-01

The diatom Sheletonema costatum is one of the dominant phytoplankton species during spring in the northern Baltic Sea. We followed the uptake of radio-labelled S, costatum by all major meiofauna species in a laboratory experiment. The uptake of labelled diatom carbon varied greatly among major

Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser

Science.gov (United States)

Decker, A. J.

1982-01-01

The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

Predicting the presence and cover of management relevant invasive plant species on protected areas.

Science.gov (United States)

Iacona, Gwenllian; Price, Franklin D; Armsworth, Paul R

2016-01-15

Invasive species are a management concern on protected areas worldwide. Conservation managers need to predict infestations of invasive plants they aim to treat if they want to plan for long term management. Many studies predict the presence of invasive species, but predictions of cover are more relevant for management. Here we examined how predictors of invasive plant presence and cover differ across species that vary in their management priority. To do so, we used data on management effort and cover of invasive plant species on central Florida protected areas. Using a zero-inflated multiple regression framework, we showed that protected area features can predict the presence and cover of the focal species but the same features rarely explain both. There were several predictors of either presence or cover that were important across multiple species. Protected areas with three days of frost per year or fewer were more likely to have occurrences of four of the six focal species. When invasive plants were present, their proportional cover was greater on small preserves for all species, and varied with surrounding household density for three species. None of the predictive features were clearly related to whether species were prioritized for management or not. Our results suggest that predictors of cover and presence can differ both within and across species but do not covary with management priority. We conclude that conservation managers need to select predictors of invasion with care as species identity can determine the relationship between predictors of presence and the more management relevant predictors of cover. Copyright © 2015 Elsevier Ltd. All rights reserved.

Subcellular binding of 239Pu in the liver of selected species of rodents

International Nuclear Information System (INIS)

Winter, R.

1980-01-01

The subcellular distribution of 239 Pu in the liver of selected rodent species was investigated as well as the relation between 239 Pu and the iron metabolism. The goal of the investigation was to find out why the liver discharge of 239 Pu from the liver varies so much between species. (orig.) [de

GC-MS Characterizations of Termiticidal Heartwood Extractives from Wood Species Utilized in Pakistan

Science.gov (United States)

Mark Mankowski; Blossie Boyd; Barbar Hassan; Grant T. Kirker

2016-01-01

Wood species that exhibit innate tolerance to wood destroying organisms such as termites are considered to be naturally durable. This durability can, in part, be due to the complex chemical compounds in the heartwood of naturally durable wood species. We examined the effects of varying concentrations of heartwood extractives on the subterranean termite, ...

Effects of exurban development and temperature on bird species in the southern Appalachians.

Science.gov (United States)

Lumpkin, Heather A; Pearson, Scott M

2013-10-01

Land-use dynamics and climatic gradients have large effects on many terrestrial systems. Exurban development, one of the fastest growing forms of land use in the United States, may affect wildlife through habitat fragmentation and building presence may alter habitat quality. We studied the effects of residential development and temperature gradients on bird species occurrence at 140 study sites in the southern Appalachian Mountains (North Carolina, U.S.A.) that varied with respect to building density and elevation. We used occupancy models to determine 36 bird species' associations with building density, forest canopy cover, average daily mean temperature, and an interaction between building density and mean temperature. Responses varied with habitat requirement, breeding range, and migration distance. Building density and mean temperature were both included in the top occupancy models for 19 of 36 species and a building density by temperature interaction was included in models for 8 bird species. As exurban development expands in the southern Appalachians, interior forest species and Neotropical migrants are likely to decline, but shrubland or edge species are not likely to benefit. Overall, effects of building density were greater than those of forest canopy cover. Exurban development had a greater effect on birds at high elevations due to a greater abundance of sensitive forest-interior species and Neotropical migrants. A warming climate may exacerbate these negative effects. © 2013 Society for Conservation Biology.

Engineering and Fabrication Considerations for Cost-Effective Space Reactor Shield Development

International Nuclear Information System (INIS)

Berg, Thomas A.; Disney, Richard K.

2004-01-01

Investment in developing nuclear power for space missions cannot be made on the basis of a single mission. Current efforts in the design and fabrication of the reactor module, including the reactor shield, must be cost-effective and take into account scalability and fabricability for planned and future missions. Engineering considerations for the shield need to accommodate passive thermal management, varying radiation levels and effects, and structural/mechanical issues. Considering these challenges, design principles and cost drivers specific to the engineering and fabrication of the reactor shield are presented that contribute to lower recurring mission costs

Chemical, Bioactive, and Antioxidant Potential of Twenty Wild Culinary Mushroom Species

Science.gov (United States)

Sharma, S. K.; Gautam, N.

2015-01-01

The chemical, bioactive, and antioxidant potential of twenty wild culinary mushroom species being consumed by the people of northern Himalayan regions has been evaluated for the first time in the present study. Nutrients analyzed include protein, crude fat, fibres, carbohydrates, and monosaccharides. Besides, preliminary study on the detection of toxic compounds was done on these species. Bioactive compounds evaluated are fatty acids, amino acids, tocopherol content, carotenoids (β-carotene, lycopene), flavonoids, ascorbic acid, and anthocyanidins. Fruitbodies extract of all the species was tested for different types of antioxidant assays. Although differences were observed in the net values of individual species all the species were found to be rich in protein, and carbohydrates and low in fat. Glucose was found to be the major monosaccharide. Predominance of UFA (65–70%) over SFA (30–35%) was observed in all the species with considerable amounts of other bioactive compounds. All the species showed higher effectiveness for antioxidant capacities. PMID:26199938

Chemical, Bioactive, and Antioxidant Potential of Twenty Wild Culinary Mushroom Species

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S. K. Sharma

2015-01-01

Full Text Available The chemical, bioactive, and antioxidant potential of twenty wild culinary mushroom species being consumed by the people of northern Himalayan regions has been evaluated for the first time in the present study. Nutrients analyzed include protein, crude fat, fibres, carbohydrates, and monosaccharides. Besides, preliminary study on the detection of toxic compounds was done on these species. Bioactive compounds evaluated are fatty acids, amino acids, tocopherol content, carotenoids (β-carotene, lycopene, flavonoids, ascorbic acid, and anthocyanidins. Fruitbodies extract of all the species was tested for different types of antioxidant assays. Although differences were observed in the net values of individual species all the species were found to be rich in protein, and carbohydrates and low in fat. Glucose was found to be the major monosaccharide. Predominance of UFA (65–70% over SFA (30–35% was observed in all the species with considerable amounts of other bioactive compounds. All the species showed higher effectiveness for antioxidant capacities.

Chemical, Bioactive, and Antioxidant Potential of Twenty Wild Culinary Mushroom Species.

Science.gov (United States)

Sharma, S K; Gautam, N

2015-01-01

The chemical, bioactive, and antioxidant potential of twenty wild culinary mushroom species being consumed by the people of northern Himalayan regions has been evaluated for the first time in the present study. Nutrients analyzed include protein, crude fat, fibres, carbohydrates, and monosaccharides. Besides, preliminary study on the detection of toxic compounds was done on these species. Bioactive compounds evaluated are fatty acids, amino acids, tocopherol content, carotenoids (β-carotene, lycopene), flavonoids, ascorbic acid, and anthocyanidins. Fruitbodies extract of all the species was tested for different types of antioxidant assays. Although differences were observed in the net values of individual species all the species were found to be rich in protein, and carbohydrates and low in fat. Glucose was found to be the major monosaccharide. Predominance of UFA (65-70%) over SFA (30-35%) was observed in all the species with considerable amounts of other bioactive compounds. All the species showed higher effectiveness for antioxidant capacities.

An Initial Evaluation of Siting Considerations on Current and Future Wind Deployment

Energy Technology Data Exchange (ETDEWEB)

Tegen, Suzanne [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lantz, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mai, Trieu [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heimiller, Donna [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hand, Maureen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ibanez, Eduardo [GE Energy Consulting, Denver, CO (United States)

2016-07-01

This report provides a deeper understanding of the wind project development process, from desktop studies to a successful project in the ground. It examines three siting consideration categories that wind project sponsors must include in the development process: wildlife (species that live in, near, or migrate through the area where wind development is possible), radar (wind turbines can cause interference with radar signals), and public engagement (representing communities and stakeholders who live near wind power projects). The research shows that although this country's abundant wind resource provides numerous options for addressing siting considerations, actually siting individual projects is becoming more difficult because of regulatory and other uncertainties. Model results are based on the premise that developers will be able to site, permit, and build successful projects, which is not always the case in reality.

Long-term variation in the winter resident bird community of Guanica Forest, Puerto Rico: lessons for measuring and monitoring species richness.

Science.gov (United States)

John Faaborg; Katie M. Dugger; Wayne J. Arendt

2007-01-01

Because the winter season is potentially limiting for migratory birds, understanding their nonbreeding distributional patterns is essential. At a given site, patterns of species occurrence and abundance may vary over time and, within a species, wintering strategies may vary with regard to the degree that individuals are site-faithful both within and between winters. We...

Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

Science.gov (United States)

Vannette, Rachel L.; Hunter, Mark D.; Rasmann, Sergio

2013-01-01

Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)—which all produce toxic cardenolides—with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

Science.gov (United States)

Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

2013-01-01

Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense.

Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

Directory of Open Access Journals (Sweden)

Rachel L Vannette

2013-09-01

Full Text Available Belowground symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above and belowground herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed--which all produce toxic cardenolides--with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in above- and below-ground plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and

Actual and potential use of population viability analyses in recovery of plant species listed under the US endangered species act.

Science.gov (United States)

Zeigler, Sara L; Che-Castaldo, Judy P; Neel, Maile C

2013-12-01

Use of population viability analyses (PVAs) in endangered species recovery planning has been met with both support and criticism. Previous reviews promote use of PVA for setting scientifically based, measurable, and objective recovery criteria and recommend improvements to increase the framework's utility. However, others have questioned the value of PVA models for setting recovery criteria and assert that PVAs are more appropriate for understanding relative trade-offs between alternative management actions. We reviewed 258 final recovery plans for 642 plants listed under the U.S. Endangered Species Act to determine the number of plans that used or recommended PVA in recovery planning. We also reviewed 223 publications that describe plant PVAs to assess how these models were designed and whether those designs reflected previous recommendations for improvement of PVAs. Twenty-four percent of listed species had recovery plans that used or recommended PVA. In publications, the typical model was a matrix population model parameterized with ≤5 years of demographic data that did not consider stochasticity, genetics, density dependence, seed banks, vegetative reproduction, dormancy, threats, or management strategies. Population growth rates for different populations of the same species or for the same population at different points in time were often statistically different or varied by >10%. Therefore, PVAs parameterized with underlying vital rates that vary to this degree may not accurately predict recovery objectives across a species' entire distribution or over longer time scales. We assert that PVA, although an important tool as part of an adaptive-management program, can help to determine quantitative recovery criteria only if more long-term data sets that capture spatiotemporal variability in vital rates become available. Lacking this, there is a strong need for viable and comprehensive methods for determining quantitative, science-based recovery criteria for

Isoprene emission from tropical tree species

International Nuclear Information System (INIS)

Padhy, P.K.; Varshney, C.K.

2005-01-01

Foliar emission of isoprene was measured in nine commonly growing tree species of Delhi, India. Dynamic flow enclosure technique was used and gas samples were collected onto Tenax-GC/Carboseive cartridges, which were then attached to the sample injection system in the gas chromatograph (GC). Eluting compounds were analysed using a flame ionisation detector (FID). Out of the nine tree species, isoprene emission was found in six species (Eucalyptus sp., Ficus benghalensis, Ficus religiosa, Mangifera indica, Melia azedarach, and Syzygium jambolanum), whereas, in the remaining three tree species (Alstonia scholaris, Azadirachta indica, and Cassia fistula) no isoprene emission was detected or the levels of emission were negligible or below the detection limit (BDL). Among six tree species, the highest hourly emission (10.2±6.8 μg g -1 leaf dry weight, average of five seasons) was observed in Ficus religiosa, while minimum emission was from Melia azedarach (2.2±4.9 μg g -1 leaf dry weight, average of five seasons). Isoprene emission (average of six species), over five seasons, was found to vary between 3.9 and 8.5 μg g -1 leaf dry weight during the rainy season. In addition, significant diurnal variation in isoprene emission was observed in each species. The preliminary estimate made in this study on the annual biogenic VOC emission from India may probably be the first of its kind from this part of the world. - Isoprene flux (diurnal and seasonal) from some tropical tree species was estimated and a regional comparison was made

Isoprene emission from tropical tree species

Energy Technology Data Exchange (ETDEWEB)

Padhy, P.K. [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)]. E-mail: padhypk2003@yahoo.com; Varshney, C.K. [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)

2005-05-01

Foliar emission of isoprene was measured in nine commonly growing tree species of Delhi, India. Dynamic flow enclosure technique was used and gas samples were collected onto Tenax-GC/Carboseive cartridges, which were then attached to the sample injection system in the gas chromatograph (GC). Eluting compounds were analysed using a flame ionisation detector (FID). Out of the nine tree species, isoprene emission was found in six species (Eucalyptus sp., Ficus benghalensis, Ficus religiosa, Mangifera indica, Melia azedarach, and Syzygium jambolanum), whereas, in the remaining three tree species (Alstonia scholaris, Azadirachta indica, and Cassia fistula) no isoprene emission was detected or the levels of emission were negligible or below the detection limit (BDL). Among six tree species, the highest hourly emission (10.2{+-}6.8 {mu}g g{sup -1} leaf dry weight, average of five seasons) was observed in Ficus religiosa, while minimum emission was from Melia azedarach (2.2{+-}4.9 {mu}g g{sup -1} leaf dry weight, average of five seasons). Isoprene emission (average of six species), over five seasons, was found to vary between 3.9 and 8.5 {mu}g g{sup -1} leaf dry weight during the rainy season. In addition, significant diurnal variation in isoprene emission was observed in each species. The preliminary estimate made in this study on the annual biogenic VOC emission from India may probably be the first of its kind from this part of the world. - Isoprene flux (diurnal and seasonal) from some tropical tree species was estimated and a regional comparison was made.

Preliminary assessment of the ecological risks to wide-ranging wildlife species on the Oak Ridge Reservation. 1996 update

Energy Technology Data Exchange (ETDEWEB)

Sample, B.E.; Hinzman, R.L.; Jackson, B.L.; Baron, L.

1996-09-01

More than approximately 50 years of operations, storage, and disposal of wastes generated by the three facilities on the Oak Ridge Reservation (ORR) (the Oak Ridge K-25 Site, Oak Ridge National Laboratory, and the Oak Ridge Y-12 Plant) has resulted in a mosaic of uncontaminated property and lands that are contaminated to varying degrees. This contaminated property includes source areas and the terrestrial and aquatic habitats down gradient from these source areas. Although the integrator OUs generally contain considerable habitat for biota, the source OUs provide little or no suitable habitat. Historically, ecological risk assessment at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites has focused on species that may be definitively associated with a contaminated area or source OU. Endpoints considered in source OUs include plants, soil/litter invertebrates and processes, aquatic biota found in on-OU sediments and surface waters, and small herbivorous, omnivorous, and vermivorous (i.e., feeding on ground, litter, or soil invertebrates) wildlife. All of these endpoints have limited spatial distributions or home ranges such that numerous individuals or a distinct population can be expected to reside within the boundaries of the source OU. Most analyses are not adequate for large sites with multiple, spatially separated contaminated areas such as the ORR that provide habitat for wide-ranging wildlife species. This report is a preliminary response to a plan for assessing risks to wide-ranging species.

Preliminary assessment of the ecological risks to wide-ranging wildlife species on the Oak Ridge Reservation. 1996 update

International Nuclear Information System (INIS)

Sample, B.E.; Hinzman, R.L.; Jackson, B.L.; Baron, L.

1996-09-01

More than approximately 50 years of operations, storage, and disposal of wastes generated by the three facilities on the Oak Ridge Reservation (ORR) (the Oak Ridge K-25 Site, Oak Ridge National Laboratory, and the Oak Ridge Y-12 Plant) has resulted in a mosaic of uncontaminated property and lands that are contaminated to varying degrees. This contaminated property includes source areas and the terrestrial and aquatic habitats down gradient from these source areas. Although the integrator OUs generally contain considerable habitat for biota, the source OUs provide little or no suitable habitat. Historically, ecological risk assessment at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites has focused on species that may be definitively associated with a contaminated area or source OU. Endpoints considered in source OUs include plants, soil/litter invertebrates and processes, aquatic biota found in on-OU sediments and surface waters, and small herbivorous, omnivorous, and vermivorous (i.e., feeding on ground, litter, or soil invertebrates) wildlife. All of these endpoints have limited spatial distributions or home ranges such that numerous individuals or a distinct population can be expected to reside within the boundaries of the source OU. Most analyses are not adequate for large sites with multiple, spatially separated contaminated areas such as the ORR that provide habitat for wide-ranging wildlife species. This report is a preliminary response to a plan for assessing risks to wide-ranging species

Modelling seasonal habitat suitability for wide-ranging species: Invasive wild pigs in northern Australia.

Directory of Open Access Journals (Sweden)

Jens G Froese

Full Text Available Invasive wildlife often causes serious damage to the economy and agriculture as well as environmental, human and animal health. Habitat models can fill knowledge gaps about species distributions and assist planning to mitigate impacts. Yet, model accuracy and utility may be compromised by small study areas and limited integration of species ecology or temporal variability. Here we modelled seasonal habitat suitability for wild pigs, a widespread and harmful invader, in northern Australia. We developed a resource-based, spatially-explicit and regional-scale approach using Bayesian networks and spatial pattern suitability analysis. We integrated important ecological factors such as variability in environmental conditions, breeding requirements and home range movements. The habitat model was parameterized during a structured, iterative expert elicitation process and applied to a wet season and a dry season scenario. Model performance and uncertainty was evaluated against independent distributional data sets. Validation results showed that an expert-averaged model accurately predicted empirical wild pig presences in northern Australia for both seasonal scenarios. Model uncertainty was largely associated with different expert assumptions about wild pigs' resource-seeking home range movements. Habitat suitability varied considerably between seasons, retracting to resource-abundant rainforest, wetland and agricultural refuge areas during the dry season and expanding widely into surrounding grassland floodplains, savanna woodlands and coastal shrubs during the wet season. Overall, our model suggested that suitable wild pig habitat is less widely available in northern Australia than previously thought. Mapped results may be used to quantify impacts, assess risks, justify management investments and target control activities. Our methods are applicable to other wide-ranging species, especially in data-poor situations.

Trait characteristics determine pyrethroid sensitivity in non-standard test species of freshwater macroinvertebrates – A reality check

DEFF Research Database (Denmark)

Wiberg-Larsen, Peter; Graeber, Daniel; Baattrup-Pedersen, Annette

2016-01-01

was recorded using automated video tracking. Most arthropod species showed mortality responses to the exposure concentrations (0.01-10 μg L(-1)), whereas nonarthropod species remained unaffected. LC50 varied by at least a factor of 1000 among arthropod species, even within the same family. This variation could...

Stomach Length and Food Preference of three Tilapia species ...

African Journals Online (AJOL)

Results showed that T . zillii was herbivorous while T . mariae and O. niloticus subsisted mainly on a wide variety of plankton. Generally, considerable quantities of zoo – and phyto-plankton were present in the food of the three species. Variations were observed in the gut lengths and dental anatomy of the tilapias which ...

Effects of Polysaccharides from Different Species of Dendrobium (Shihu on Macrophage Function

Directory of Open Access Journals (Sweden)

Lan-Zhen Meng

2013-05-01

Full Text Available Dendrobium spp. are precious medicinal plants, used in China for thousands of years as health foods and nutrients. Polysaccharides are the main effective ingredients in Dendrobium plants. In this study, the chemical characteristics and the effects of crude polysaccharides (CPs from five species of Dendrobium on macrophage function were investigated and compared in vitro for the first time. Chemical characteristic studies showed that CPs from different species of Dendrobium were diverse, displaying widely varied Mw distributions and molar ratios of monosaccharides. Their effects on macrophage functions, such as promoting phagocytosis, release of NO and cytokines IL-1α, IL-6, IL-10 and TNF-α, were also different. Moreover, CPs from D. officinale, especially collected from Yunnan Province, exerted the strongest immunomodulatory activities and could be explored as a novel potential functional food. The diverse chemical characteristics of CPs from different species of Dendrobium might contribute to their varied effects on macrophage functions, which should be further investigated.

Tree-Dwelling Ants: Contrasting Two Brazilian Cerrado Plant Species without Extrafloral Nectaries

Directory of Open Access Journals (Sweden)

Jonas Maravalhas

2012-01-01

Full Text Available Ants dominate vegetation stratum, exploiting resources like extrafloral nectaries (EFNs and insect honeydew. These interactions are frequent in Brazilian cerrado and are well known, but few studies compare ant fauna and explored resources between plant species. We surveyed two cerrado plants without EFNs, Roupala montana (found on preserved environments of our study area and Solanum lycocarpum (disturbed ones. Ants were collected and identified, and resources on each plant noted. Ant frequency and richness were higher on R. montana (67%; 35 spp than S. lycocarpum (52%; 26, the occurrence of the common ant species varied between them, and similarity was low. Resources were explored mainly by Camponotus crassus and consisted of scale insects, aphids, and floral nectaries on R. montana and two treehopper species on S. lycocarpum. Ants have a high diversity on cerrado plants, exploring liquid and prey-based resources that vary in time and space and affect their presence on plants.

Effects of polysaccharides from different species of Dendrobium (Shihu) on macrophage function.

Science.gov (United States)

Meng, Lan-Zhen; Lv, Guang-Ping; Hu, De-Jun; Cheong, Kit-Leong; Xie, Jing; Zhao, Jing; Li, Shao-Ping

2013-05-17

Dendrobium spp. are precious medicinal plants, used in China for thousands of years as health foods and nutrients. Polysaccharides are the main effective ingredients in Dendrobium plants. In this study, the chemical characteristics and the effects of crude polysaccharides (CPs) from five species of Dendrobium on macrophage function were investigated and compared in vitro for the first time. Chemical characteristic studies showed that CPs from different species of Dendrobium were diverse, displaying widely varied Mw distributions and molar ratios of monosaccharides. Their effects on macrophage functions, such as promoting phagocytosis, release of NO and cytokines IL-1α, IL-6, IL-10 and TNF-α, were also different. Moreover, CPs from D. officinale, especially collected from Yunnan Province, exerted the strongest immunomodulatory activities and could be explored as a novel potential functional food. The diverse chemical characteristics of CPs from different species of Dendrobium might contribute to their varied effects on macrophage functions, which should be further investigated.

Measuring the Insecurity Index of species in networks of protected areas using species distribution modeling and fuzzy logic: The case of raptors in Andalusia

NARCIS (Netherlands)

Diaz-Gomez, D.L.; Toxopeus, A.G.; Groen, T.A.; Munoz, A.R.; Skidmore, A.K.; Real, R.

2013-01-01

Networks of protected areas often fail to include favorable areas for all species, even when they cover a considerable percentage of a territory. To assess the effectiveness of protected areas, harsh thresholds are commonly used (e.g. minimum 20% of the cell must be covered by a protected area to

Why do morphological phylogenies vary in quality? An investigation based on the comparative history of lizard clades.

Science.gov (United States)

Arnold, E N

1990-05-22

Phylogenies based on morphology vary considerably in their quality: some are robust and explicit with little conflict in the data set, whereas others are far more tenuous, with much conflict and many possible alternatives. The main primary reasons for untrue or inexplicit morphological phylogenies are: not enough characters developed between branching points, uncertain character polarity, poorly differentiated character states, homoplasy caused by parallelism or reversal, and extinction, which may remove species entirely from consideration and can make originally conflicting data sets misleadingly compatible, increasing congruence at the expense of truth. Extinction differs from other confounding factors in not being apparent either in the data set or in subsequent analysis. One possibility is that variation in the quality of morphological phylogenies has resulted from exposure to different ecological situations. To investigate this, it is necessary to compare the histories of the clades concerned. In the case of explicit morphological phylogenies, ecological and behavioural data can be integrated with them and it may then be possible to decide whether morphological characters are likely to have been elicited by the environments through which the clade has passed. The credibility of such results depends not only on the phylogeny being robust but also on its detailed topology: a pectinate phylogeny will often allow more certain and more explicit statements to be made about historical events. In the case of poor phylogenies, it is not possible to produce detailed histories, but they can be compared with robust phylogenies in the range of ecological situations occupied, and whether they occupy novel situations in comparison with their outgroups. LeQuesne testing can give information about niche homoplasy, and it may also be possible to see if morphological features are functionally associated with ecological parameters, even if the direction of change is unknown

Genetic characterization, species differentiation and detection of Fasciola spp. by molecular approaches.

Science.gov (United States)

Ai, Lin; Chen, Mu-Xin; Alasaad, Samer; Elsheikha, Hany M; Li, Juan; Li, Hai-Long; Lin, Rui-Qing; Zou, Feng-Cai; Zhu, Xing-Quan; Chen, Jia-Xu

2011-06-10

Liver flukes belonging to the genus Fasciola are among the causes of foodborne diseases of parasitic etiology. These parasites cause significant public health problems and substantial economic losses to the livestock industry. Therefore, it is important to definitively characterize the Fasciola species. Current phenotypic techniques fail to reflect the full extent of the diversity of Fasciola spp. In this respect, the use of molecular techniques to identify and differentiate Fasciola spp. offer considerable advantages. The advent of a variety of molecular genetic techniques also provides a powerful method to elucidate many aspects of Fasciola biology, epidemiology, and genetics. However, the discriminatory power of these molecular methods varies, as does the speed and ease of performance and cost. There is a need for the development of new methods to identify the mechanisms underpinning the origin and maintenance of genetic variation within and among Fasciola populations. The increasing application of the current and new methods will yield a much improved understanding of Fasciola epidemiology and evolution as well as more effective means of parasite control. Herein, we provide an overview of the molecular techniques that are being used for the genetic characterization, detection and genotyping of Fasciola spp..

Tree phyllosphere bacterial communities: exploring the magnitude of intra- and inter-individual variation among host species

Directory of Open Access Journals (Sweden)

Isabelle Laforest-Lapointe

2016-08-01

Full Text Available Background The diversity and composition of the microbial community of tree leaves (the phyllosphere varies among trees and host species and along spatial, temporal, and environmental gradients. Phyllosphere community variation within the canopy of an individual tree exists but the importance of this variation relative to among-tree and among-species variation is poorly understood. Sampling techniques employed for phyllosphere studies include picking leaves from one canopy location to mixing randomly selected leaves from throughout the canopy. In this context, our goal was to characterize the relative importance of intra-individual variation in phyllosphere communities across multiple species, and compare this variation to inter-individual and interspecific variation of phyllosphere epiphytic bacterial communities in a natural temperate forest in Quebec, Canada. Methods We targeted five dominant temperate forest tree species including angiosperms and gymnosperms: Acer saccharum, Acer rubrum, Betula papyrifera, Abies balsamea and Picea glauca. For one randomly selected tree of each species, we sampled microbial communities at six distinct canopy locations: bottom-canopy (1–2 m height, the four cardinal points of mid-canopy (2–4 m height, and the top-canopy (4–6 m height. We also collected bottom-canopy leaves from five additional trees from each species. Results Based on an analysis of bacterial community structure measured via Illumina sequencing of the bacterial 16S gene, we demonstrate that 65% of the intra-individual variation in leaf bacterial community structure could be attributed to the effect of inter-individual and inter-specific differences while the effect of canopy location was not significant. In comparison, host species identity explains 47% of inter-individual and inter-specific variation in leaf bacterial community structure followed by individual identity (32% and canopy location (6%. Discussion Our results suggest that

Studies on fluctuating asymmetry (FA for certain morphological traits in four species of the Drosophila bipectinata complex

Directory of Open Access Journals (Sweden)

Banerjee Parul

2015-01-01

Full Text Available Fluctuating asymmetry (FA is defined as subtle deviations from perfect bilateral symmetry, evident in differences between the right and the left sides of any given trait. It is a pattern of variation between sides and measures developmental instability. Differences in the level of FA may be used for comparing developmental precision among closely related species and thus may give an idea whether developmental stability was affected during the divergence and separation of populations into distinct species. Keeping this in view, FA was studied in four species of the Drosophila bipectinata complex i.e. D. bipectinata, D. parabipectinata, D. malerkotliana and D. pseudoananassae. In females of all the four species, FA values did not vary significantly for any of the traits considered. However, in case of males, they varied significantly for Wing length (WL and sex comb tooth number (SCTN. Also, while in females Composite fluctuating asymmetry (CFA did not exhibit significant variation, in males it was found to vary significantly across the four species. However, Bonferroni t-tests did not reveal any consistent difference in FA levels between any two species. The magnitude of FA was found to differ significantly among traits and CFA values were found to be higher for males than females in all the four species. Therefore, it may be concluded that the level of FA shows trait specific variations and males are more prone to developmental perturbations. However, the FA levels are more or less similar in all the four species of this complex. Thus, developmental precision remains nearly same in all the four species of this complex irrespective of the degree of evolutionary divergence reached.

New flux based dose-response relationships for ozone for European forest tree species.

Science.gov (United States)

Büker, P; Feng, Z; Uddling, J; Briolat, A; Alonso, R; Braun, S; Elvira, S; Gerosa, G; Karlsson, P E; Le Thiec, D; Marzuoli, R; Mills, G; Oksanen, E; Wieser, G; Wilkinson, M; Emberson, L D

2015-11-01

To derive O3 dose-response relationships (DRR) for five European forest trees species and broadleaf deciduous and needleleaf tree plant functional types (PFTs), phytotoxic O3 doses (PODy) were related to biomass reductions. PODy was calculated using a stomatal flux model with a range of cut-off thresholds (y) indicative of varying detoxification capacities. Linear regression analysis showed that DRR for PFT and individual tree species differed in their robustness. A simplified parameterisation of the flux model was tested and showed that for most non-Mediterranean tree species, this simplified model led to similarly robust DRR as compared to a species- and climate region-specific parameterisation. Experimentally induced soil water stress was not found to substantially reduce PODy, mainly due to the short duration of soil water stress periods. This study validates the stomatal O3 flux concept and represents a step forward in predicting O3 damage to forests in a spatially and temporally varying climate. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Variability in leaf optical properties among 26 species from a broad range of habitats

International Nuclear Information System (INIS)

Knapp, A.K.; Carter, G.A.

1998-01-01

Leaves from 26 species with growth forms from annual herbs to trees were collected from open, intermediate, and shaded understory habitats in Mississippi and Kansas, USA. Leaf optical properties including reflectance, transmittance, and absorptance in visible and near infrared (NIR) wavelengths were measured along with leaf thickness and specific leaf mass (SLM). These leaf properties and internal light scattering have been reported to vary with light availability in studies that have focused on a limited number of species. Our objective was to determine whether these patterns in leaf optics and light availability were consistent when a greater number of species were evaluated. Leaf thickness and SLM varied by tenfold among species sampled, but within-habitat variance was high. Although there was a strong trend toward thicker leaves in open habitats, only SLM was significantly greater in open vs. understory habitats. In contrast, leaf optical properties were strikingly similar among habitats. Reflectance and reflectance/transmittance in the NIR were used to estimate internal light scattering and there were strong relationships (r2 0.65) between these optical properties and leaf thickness. We concluded that leaf thickness, which did not vary consistently among habitats, was the best predictor of NIR reflectance and internal light scattering. However, because carbon allocation to leaves was lower in understory species (low SLM) yet gross optical properties were similar among all habitats, the energy investment by shade leaves required to achieve optical equivalence with sun leaves was lower. Differences in leaf longevity and growth form within a habitat may help explain the lack of consistent patterns in leaf optics as the number of species sampled increases

The Effect of Size and Species on Lens Intracellular Hydrostatic Pressure

Science.gov (United States)

Gao, Junyuan; Sun, Xiurong; Moore, Leon C.; Brink, Peter R.; White, Thomas W.; Mathias, Richard T.

2013-01-01

Purpose. Previous experiments showed that mouse lenses have an intracellular hydrostatic pressure that varied from 335 mm Hg in central fibers to 0 mm Hg in surface cells. Model calculations predicted that in larger lenses, all else equal, pressure should increase as the lens radius squared. To test this prediction, lenses of different radii from different species were studied. Methods. All studies were done in intact lenses. Intracellular hydrostatic pressures were measured with a microelectrode-manometer–based system. Membrane conductances were measured by frequency domain impedance analysis. Intracellular Na+ concentrations were measured by injecting the Na+-sensitive dye sodium-binding benzofuran isophthalate. Results. Intracellular hydrostatic pressures were measured in lenses from mice, rats, rabbits, and dogs with radii (cm) 0.11, 0.22, 0.49, and 0.57, respectively. In each species, pressure varied from 335 ± 6 mm Hg in central fiber cells to 0 mm Hg in surface cells. Further characterization of transport in lenses from mice and rats showed that the density of fiber cell gap junction channels was approximately the same, intracellular Na+ concentrations varied from 17 mM in central fiber cells to 7 mM in surface cells, and intracellular voltages varied from −45 mV in central fiber cells to −60 mV in surface cells. Fiber cell membrane conductance was a factor of 2.7 times larger in mouse than in rat lenses. Conclusions. Intracellular hydrostatic pressure is an important physiological parameter that is regulated in lenses from these different species. The most likely mechanism of regulation is to reduce the density of open Na+-leak channels in fiber cells of larger lenses. PMID:23211824

SHort Note Diet variability in the White Stork Ciconia ciconia in ...

African Journals Online (AJOL)

Coleoptera species were the most frequently consumed prey during all months and years, followed by Dermaptera species, except in 1998 when Orthoptera were more frequent. The frequency of families of prey insects varied considerably depending on the year: Carabidae were dominant in 2007, Tenebrionidae in 1999 ...

Trawling disturbance on benthic ecosystems and consequences on commercial species: a northwestern Mediterranean case study

Directory of Open Access Journals (Sweden)

Alba Muntadas

2014-03-01

Full Text Available Trawling is known to disturb benthic communities and habitats, which may in turn indirectly affect populations of commercial species that live in close association with the seabed. The degree of impact on both benthic communities and demersal species depends on the fishing effort level. This may vary over the year because of the fleet dynamics, which are in turn normally driven by the main target species’ life cycle. In this study we describe changes in benthic functional components of a northwestern Mediterranean fishing ground that represents a recruitment area for an important target species (red mullet, Mullus barbatus. This fishing ground experiences a varying intensity of fishing effort over the year and benthic functional components under different levels of trawling were compared with an unfished, control area. Traits related to sexual maturity and life span for infauna and body size and life span for epifauna were found to vary with fishing activity. Potential effects of these changes on ecological functioning and the impact on red mullet population are discussed. The development of fisheries management plans under an ecosystem based fisheries management (EBFM requires the links between target species and benthic communities’ disturbance due to fishing practices to be explicitly considered.

Oral bioaccessibility of toxic and essential elements in raw and cooked commercial seafood species available in European markets

DEFF Research Database (Denmark)

Alves, Ricardo N.; Maulvault, Ana L.; Barbosa, Vera L.

2017-01-01

The oral bioaccessibility of several essential and toxic elements was investigated in raw and cooked commercially available seafood species from European markets. Bioaccessibility varied between seafood species and elements. Methylmercury bioaccessibility varied between 10 (octopus) and 60...... % (monkfish). Arsenic (> 64%) was the toxic element showing the highest bioaccessibility. Concerning essential elements bioaccessibility in raw seafood, selenium (73 %) and iodine (71 %) revealed the highest percentages. The bioaccessibility of elements in steamed products increased or decreased according...

Pathobiology of avian influenza virus infection in minor gallinaceous species: a review.

Science.gov (United States)

Bertran, Kateri; Dolz, Roser; Majó, Natàlia

2014-01-01

Susceptibility to avian influenza viruses (AIVs) can vary greatly among bird species. Chickens and turkeys are major avian species that, like ducks, have been extensively studied for avian influenza. To a lesser extent, minor avian species such as quail, partridges, and pheasants have also been investigated for avian influenza. Usually, such game fowl species are highly susceptible to highly pathogenic AIVs and may consistently spread both highly pathogenic AIVs and low-pathogenic AIVs. These findings, together with the fact that game birds are considered bridge species in the poultry-wildlife interface, highlight their interest from the transmission and biosecurity points of view. Here, the general pathobiological features of low-pathogenic AIV and highly pathogenic AIV infections in this group of avian species have been covered.

Ethical, Legal, and Clinical Considerations when Disclosing a High-Risk Syndrome for Psychosis.

Science.gov (United States)

Mittal, Vijay A; Dean, Derek J; Mittal, Jyoti; Saks, Elyn R

2015-10-01

There are complex considerations when planning to disclose an attenuated psychosis syndrome (APS) diagnosis. In this review, we evaluate ethical, legal, and clinical perspectives as well as caveats related to full, non- and partial disclosure strategies, discuss societal implications, and provide clinical suggestions. Each of the disclosure strategies is associated with benefits as well as costs/considerations. Full disclosure promotes autonomy, allows for the clearest psychoeducation about additional risk factors, helps to clarify and/or correct previous diagnoses/treatments, facilitates early intervention and bolsters communication between providers but there are important considerations involving heritability, comorbidity, culture, and stigma. Non-disclosure advances nonmaleficence by limiting stigma and stress (which may inadvertently exacerbate the condition), and confusion (related to the rapidly evolving diagnosis) in a sensitive developmental period but is complicated by varying patient preferences and the possibility that, as new treatments without adverse effects become available, the risk with false positives no longer justifies the accompanying loss of autonomy. Partial disclosure balances ethical considerations by focusing on symptoms instead of labels, but evidence that laypersons may interpret this information as a pseudo-diagnosis and that symptoms alone also contribute to stigma limits the efficacy of this approach. In addition, there are notable societal considerations relating to disclosure involving conservatorship, the reach of insurance companies, and discrimination. We advocate a hybrid approach to disclosure and recommend future research aimed at understanding the effects of stigma on clinical course and a renewed focus on those help-seeking cases that do not transition but remain clinically relevant. © 2015 John Wiley & Sons Ltd.

Comparison of the chemical compositions and nutritive values of various pumpkin (Cucurbitaceae) species and parts

Science.gov (United States)

Kim, Mi Young; Kim, Eun Jin; Kim, Young-Nam; Choi, Changsun

2012-01-01

Pumpkins have considerable variation in nutrient contents depending on the cultivation environment, species, or part. In this study, the general chemical compositions and some bioactive components, such as tocopherols, carotenoids, and β-sitosterol, were analyzed in three major species of pumpkin (Cucurbitaceae pepo, C. moschata, and C. maxima) grown in Korea and also in three parts (peel, flesh, and seed) of each pumpkin species. C. maxima had significantly more carbohydrate, protein, fat, and fiber than C. pepo or C. moschata (P pumpkin was highest in C. pepo. The major fatty acids in the seeds were palmitic, stearic, oleic, and linoleic acids. C. pepo and C. moschata seeds had significantly more γ-tocopherol than C. maxima, whose seeds had the highest β-carotene content. C. pepo seeds had significantly more β-sitosterol than the others. Nutrient compositions differed considerably among the pumpkin species and parts. These results will be useful in updating the nutrient compositions of pumpkin in the Korean food composition database. Additional analyses of various pumpkins grown in different years and in different areas of Korea are needed. PMID:22413037

Effect of species rarity on the accuracy of species distribution models for reptiles and amphibians in southern California

Science.gov (United States)

Franklin, J.; Wejnert, K.E.; Hathaway, S.A.; Rochester, C.J.; Fisher, R.N.

2009-01-01

Aim: Several studies have found that more accurate predictive models of species' occurrences can be developed for rarer species; however, one recent study found the relationship between range size and model performance to be an artefact of sample prevalence, that is, the proportion of presence versus absence observations in the data used to train the model. We examined the effect of model type, species rarity class, species' survey frequency, detectability and manipulated sample prevalence on the accuracy of distribution models developed for 30 reptile and amphibian species. Location: Coastal southern California, USA. Methods: Classification trees, generalized additive models and generalized linear models were developed using species presence and absence data from 420 locations. Model performance was measured using sensitivity, specificity and the area under the curve (AUC) of the receiver-operating characteristic (ROC) plot based on twofold cross-validation, or on bootstrapping. Predictors included climate, terrain, soil and vegetation variables. Species were assigned to rarity classes by experts. The data were sampled to generate subsets with varying ratios of presences and absences to test for the effect of sample prevalence. Join count statistics were used to characterize spatial dependence in the prediction errors. Results: Species in classes with higher rarity were more accurately predicted than common species, and this effect was independent of sample prevalence. Although positive spatial autocorrelation remained in the prediction errors, it was weaker than was observed in the species occurrence data. The differences in accuracy among model types were slight. Main conclusions: Using a variety of modelling methods, more accurate species distribution models were developed for rarer than for more common species. This was presumably because it is difficult to discriminate suitable from unsuitable habitat for habitat generalists, and not as an artefact of the

Diversification rates and species richness across the Tree of Life.

Science.gov (United States)

Scholl, Joshua P; Wiens, John J

2016-09-14

Species richness varies dramatically among clades across the Tree of Life, by over a million-fold in some cases (e.g. placozoans versus arthropods). Two major explanations for differences in richness among clades are the clade-age hypothesis (i.e. species-rich clades are older) and the diversification-rate hypothesis (i.e. species-rich clades diversify more rapidly, where diversification rate is the net balance of speciation and extinction over time). Here, we examine patterns of variation in diversification rates across the Tree of Life. We address how rates vary across higher taxa, whether rates within higher taxa are related to the subclades within them, and how diversification rates of clades are related to their species richness. We find substantial variation in diversification rates, with rates in plants nearly twice as high as in animals, and rates in some eukaryotes approximately 10-fold faster than prokaryotes. Rates for each kingdom-level clade are then significantly related to the subclades within them. Although caution is needed when interpreting relationships between diversification rates and richness, a positive relationship between the two is not inevitable. We find that variation in diversification rates seems to explain most variation in richness among clades across the Tree of Life, in contrast to the conclusions of previous studies. © 2016 The Author(s).

Comparative ecomorphology of the cyathial nectaries in eight European Euphorbia species.

Science.gov (United States)

Papp, Nóra; Csete, S; Farkas, Agnes

2013-03-01

The morphology and histology of the cyathial nectary were studied in 8 European leafy spurge (Euphorbia) species, revealing that certain histological traits of the glands are in close correlation to each species' habitat, underlining the importance of morphological evidences in determining relevant ecological tolerance spectra of plants.The structure of the cyathial glands was studied in longitudinal sections with light microscopy, and histological parameters were measured and statistically analyzed by appropriate softwares.The nectaries consist of a cuticle-covered epidermis, formed by palisade cells, under which the glandular tissue and parenchyma are composed of isodiametric and anisodiametric cells in all species. Thickness of cuticle, position of nectary stomata and number of rows comprising the glandular tissue vary to a great extent in plants living in xeric, humid or mesic habitats.Although all the studied anatomical features of the nectaries were expected to be in correspondence with the characteristics of habitat types, we have only found the number of glandular cell rows to be in strong correlation with the Ellenberg's ecological indicator values on soil moisture, which varied with species. The recorded anatomical differences among the studied Euphorbia taxa emphasize the ecological significance of glandular tissue in plant adaptation, which can also be relevant for systematic purposes.

The ethics of reviving long extinct species.

Science.gov (United States)

Sandler, Ronald

2014-04-01

There now appears to be a plausible pathway for reviving species that have been extinct for several decades, centuries, or even millennia. I conducted an ethical analysis of de-extinction of long extinct species. I assessed several possible ethical considerations in favor of pursuing de-extinction: that it is a matter of justice; that it would reestablish lost value; that it would create new value; and that society needs it as a conservation last resort. I also assessed several possible ethical arguments against pursuing de-extinction: that it is unnatural; that it could cause animal suffering; that it could be ecologically problematic or detrimental to human health; and that it is hubristic. There are reasons in favor of reviving long extinct species, and it can be ethically acceptable to do so. However, the reasons in favor of pursuing de-extinction do not have to do with its usefulness in species conservation; rather, they concern the status of revived species as scientific and technological achievements, and it would be ethically problematic to promote de-extinction as a significant conservation strategy, because it does not prevent species extinctions, does not address the causes of extinction, and could be detrimental to some species conservation efforts. Moreover, humanity does not have a responsibility or obligation to pursue de-extinction of long extinct species, and reviving them does not address any urgent problem. Therefore, legitimate ecological, political, animal welfare, legal, or human health concerns associated with a de-extinction (and reintroduction) must be thoroughly addressed for it to be ethically acceptable. © 2013 Society for Conservation Biology.

Quantifying root-reinforcement of river bank soils by four Australian tree species

Science.gov (United States)

Docker, B. B.; Hubble, T. C. T.

2008-08-01

The increased shear resistance of soil due to root-reinforcement by four common Australian riparian trees, Casuarina glauca, Eucalyptus amplifolia, Eucalyptus elata and Acacia floribunda, was determined in-situ with a field shear-box. Root pull-out strengths and root tensile-strengths were also measured and used to evaluate the utility of the root-reinforcement estimation models that assume simultaneous failure of all roots at the shear plane. Field shear-box results indicate that tree roots fail progressively rather than simultaneously. Shear-strengths calculated for root-reinforced soil assuming simultaneous root failure, yielded values between 50% and 215% higher than directly measured shear-strengths. The magnitude of the overestimate varies among species and probably results from differences in both the geometry of the root-system and tensile strengths of the root material. Soil blocks under A. floribunda which presents many, well-spread, highly-branched fine roots with relatively higher tensile strength, conformed most closely with root model estimates; whereas E. amplifolia, which presents a few, large, unbranched vertical roots, concentrated directly beneath the tree stem and of relatively low tensile strength, deviated furthest from model-estimated shear-strengths. These results suggest that considerable caution be exercised when applying estimates of increased shear-strength due to root-reinforcement in riverbank stability modelling. Nevertheless, increased soil shear strength provided by tree roots can be calculated by knowledge of the Root Area Ratio ( RAR) at the shear plane. At equivalent RAR values, A. floribunda demonstrated the greatest earth reinforcement potential of the four species studied.

DOE handbook: Design considerations

International Nuclear Information System (INIS)

1999-04-01

The Design Considerations Handbook includes information and suggestions for the design of systems typical to nuclear facilities, information specific to various types of special facilities, and information useful to various design disciplines. The handbook is presented in two parts. Part 1, which addresses design considerations, includes two sections. The first addresses the design of systems typically used in nuclear facilities to control radiation or radioactive materials. Specifically, this part addresses the design of confinement systems and radiation protection and effluent monitoring systems. The second section of Part 1 addresses the design of special facilities (i.e., specific types of nonreactor nuclear facilities). The specific design considerations provided in this section were developed from review of DOE 6430.1A and are supplemented with specific suggestions and considerations from designers with experience designing and operating such facilities. Part 2 of the Design Considerations Handbook describes good practices and design principles that should be considered in specific design disciplines, such as mechanical systems and electrical systems. These good practices are based on specific experiences in the design of nuclear facilities by design engineers with related experience. This part of the Design Considerations Handbook contains five sections, each of which applies to a particular engineering discipline

DOE handbook: Design considerations

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-04-01

The Design Considerations Handbook includes information and suggestions for the design of systems typical to nuclear facilities, information specific to various types of special facilities, and information useful to various design disciplines. The handbook is presented in two parts. Part 1, which addresses design considerations, includes two sections. The first addresses the design of systems typically used in nuclear facilities to control radiation or radioactive materials. Specifically, this part addresses the design of confinement systems and radiation protection and effluent monitoring systems. The second section of Part 1 addresses the design of special facilities (i.e., specific types of nonreactor nuclear facilities). The specific design considerations provided in this section were developed from review of DOE 6430.1A and are supplemented with specific suggestions and considerations from designers with experience designing and operating such facilities. Part 2 of the Design Considerations Handbook describes good practices and design principles that should be considered in specific design disciplines, such as mechanical systems and electrical systems. These good practices are based on specific experiences in the design of nuclear facilities by design engineers with related experience. This part of the Design Considerations Handbook contains five sections, each of which applies to a particular engineering discipline.

Redescription of the Advertisement Call of Five Species of Thoropa (Anura, Cycloramphidae, Including Recordings of Rare and Endangered Species.

Directory of Open Access Journals (Sweden)

Carlos H L Nunes-de-Almeida

Full Text Available Frogs of the genus Thoropa comprise six endemic Brazilian species on the Eastern side of the country. Little is known about their natural history, especially about their acoustic communication. Therefore, aiming to provide an overview of their vocalizations, we analyzed and redescribed male advertisement calls of three living and two possibly extinct species. The smaller species, T. petropolitana and T. lutzi, produce simple calls (one single note with a higher frequency range than the remaining larger ones. On the other hand, the larger species present complex calls, with more than one note: T. megatympanum calls have three notes, T. taophora calls have four notes, and T. miliaris calls varies from three to six notes. Population snout-vent length negatively correlated with peak of dominant frequency as expected. However, highlighted differences between two populations of T. lutzi, which could indicate need of further taxonomic evaluation of those lineages. Peculiar morphology, such as the absence of vocal sacs and slits, may have contributed to their call variation and highly banded frequency structure. If the observed population differences reflect species-level differences, T. lutzi may be classified as a critically endangered species, as T. petropolitana. Furthermore, we provided a suggestion to an unusual behavior in frogs: calling with the mouth open in the smaller species of the genus.

Design consideration on severe accident for future LWR

International Nuclear Information System (INIS)

Omoto, A.

1998-01-01

Utilities' Severe Accident Management strategies, selected based on Individual Plant Examination, are in the process of implementation for each operating plant. Activities for the next generation LWR design are going on by Utilities, NSSS vendors and Research Institutes. The proposed new designs vary from evolutionary design to revolutionary design such as the supercritical LWR. Discussion on the consideration of Severe Accident in the design of next generation LWR is being held to establish the industry's self-regulatory document on containment design and its performance, which ABWR-IER (Improved Evolutionary Reactor) on the part of BWR and Evolutionary APWR and New PWR21 on the part of PWR are expected to comply. Conceptual design study for ABWR-IER will illustrate an example of design approach for the prevention and mitigation of Severe Accident and its impact on capital cost

Comparison of oostegite shapes in some gammaroidean species (Crustacea: Amphipoda)

NARCIS (Netherlands)

Steele, D.H.

1990-01-01

Within the superfamily Gammaroidea oostegites vary from broad (primitive) to narrow (advanced). Broad oostegites are found in members of the Acanthogammaridae, Macrohectopidae and a few of the Gammaridae. Most species of the family Gammaridae have broad anterior oostegites and narrow posterior ones.

Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

Directory of Open Access Journals (Sweden)

Astrid Welk

Full Text Available This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account.

Investigation of severe UF membrane fouling induced by three marine algal species

KAUST Repository

Merle, Tony; Dramas, Laure; Gutierrez, Leonardo; Garcia-Molina, Veronica; Croue, Jean-Philippe

2016-01-01

Index (HIFI) was correlated to their biopolymer content but this correlation is specific for each species. Solution pre-filtration through a 1.2 μm membrane proved that cells and particulate algal organic matter (p-AOM) considerably contribute to fouling

A varying-α brane world cosmology

International Nuclear Information System (INIS)

Youm, Donam

2001-08-01

We study the brane world cosmology in the RS2 model where the electric charge varies with time in the manner described by the varying fine-structure constant theory of Bekenstein. We map such varying electric charge cosmology to the dual variable-speed-of-light cosmology by changing system of units. We comment on cosmological implications for such cosmological models. (author)

Enrofloxacin: pharmacokinetics and metabolism in domestic animal species.

Science.gov (United States)

López-Cadenas, Cristina; Sierra-Vega, Matilde; García-Vieitez, Juan J; Diez-Liébana, M José; Sahagún-Prieto, Ana; Fernández-Martínez, Nélida

2013-12-01

Enrofloxacin is a fluorquinolone exclusively developed for use in veterinary medicine (1980). The kinetics of enrofloxacin are characterized, in general terms, by high bioavailability in most species and rapid absorption after IM, SC or oral administration. However, several studies reported that enrofloxacin showed low bioavailability after oral administration in ruminants. This drug has a broad distribution in the organism, excellent tissue penetration and long serum half-life. Also, enrofloxacin is characterized by a low host toxicity, a broad antibacterial spectrum and high bactericidal activity against major pathogenic bacteria (both Gram-positive and Gram-negative), and intracellular organisms found in diseased animals. The kinetics vary according to the route of administration, formulation, animal species, age, body condition, and physiological status, all of which contribute to differences in drug efficacy. The pharmacokinetic properties of drugs are closely related to their pharmacological efficiency, so it is important to know their behavior in each species that is used. This article reviews the pharmacokinetics of enrofloxacin in several domestic animal species.

Geomorphic controls on elevational gradients of species richness.

Science.gov (United States)

Bertuzzo, Enrico; Carrara, Francesco; Mari, Lorenzo; Altermatt, Florian; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

2016-02-16

Elevational gradients of biodiversity have been widely investigated, and yet a clear interpretation of the biotic and abiotic factors that determine how species richness varies with elevation is still elusive. In mountainous landscapes, habitats at different elevations are characterized by different areal extent and connectivity properties, key drivers of biodiversity, as predicted by metacommunity theory. However, most previous studies directly correlated species richness to elevational gradients of potential drivers, thus neglecting the interplay between such gradients and the environmental matrix. Here, we investigate the role of geomorphology in shaping patterns of species richness. We develop a spatially explicit zero-sum metacommunity model where species have an elevation-dependent fitness and otherwise neutral traits. Results show that ecological dynamics over complex terrains lead to the null expectation of a hump-shaped elevational gradient of species richness, a pattern widely observed empirically. Local species richness is found to be related to the landscape elevational connectivity, as quantified by a newly proposed metric that applies tools of complex network theory to measure the closeness of a site to others with similar habitat. Our theoretical results suggest clear geomorphic controls on elevational gradients of species richness and support the use of the landscape elevational connectivity as a null model for the analysis of the distribution of biodiversity.

Mistaking geography for biology: inferring processes from species distributions.

Science.gov (United States)

Warren, Dan L; Cardillo, Marcel; Rosauer, Dan F; Bolnick, Daniel I

2014-10-01

Over the past few decades, there has been a rapid proliferation of statistical methods that infer evolutionary and ecological processes from data on species distributions. These methods have led to considerable new insights, but they often fail to account for the effects of historical biogeography on present-day species distributions. Because the geography of speciation can lead to patterns of spatial and temporal autocorrelation in the distributions of species within a clade, this can result in misleading inferences about the importance of deterministic processes in generating spatial patterns of biodiversity. In this opinion article, we discuss ways in which patterns of species distributions driven by historical biogeography are often interpreted as evidence of particular evolutionary or ecological processes. We focus on three areas that are especially prone to such misinterpretations: community phylogenetics, environmental niche modelling, and analyses of beta diversity (compositional turnover of biodiversity). Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Entomopathogenic Potential of Verticillium and Acremonium Species (Deuteromycotina: Hyphomycetes)

DEFF Research Database (Denmark)

Steenberg, Tove; Humber, Richard A

1999-01-01

their entomopathogenicity. A test was also conducted with a coleopteran (lesser mealworm, Alphitobius diaperinus) to further evaluate the host range for some of the fungi. V. lamellicola was not pathogenic to the two species of insects treated, while varying levels of pathogenicity were shown for the other species....... In general, V. lecanii was the most pathogenic species. Immature whiteflies appeared to be more susceptible to fungal infection than adult houseflies, and the host range for several of the fungi also included lesser mealworm....

Effects of fluorine on the germination of some species of seeds

Energy Technology Data Exchange (ETDEWEB)

Navara, J; Holub, Z; Bedatsova, L

1966-01-01

The various degrees of tolerance of the seeds of some species of plants towards fluorine and their ability to accumulate fluorine under experimental conditions are presented. The effects of fluorine on the germination of seeds manifests itself in various ways. The studied species have been divided into four groups according to their natural tolerance: (1) very sensitive: pea, soya, vetch and cabbage; (2) sensitive: radish, barley, cole; (3) less sensitive: maize, cauliflower, alfalfa, mustard, oats, clover kohlrabi; and (4) tolerant: poppy, carrot, tomato. Highly tolerant species are capable of accumulating considerable amounts of fluorine when compared with the more sensitive species. A more intensive accumulation of fluorine has been noticed in the oleaginous species, viz. mustard and poppy. A correlation was found to exist between the ash contents (especially of calcium) and the ability of a greater accumulation of fluorine. 23 references, 6 figures, 2 tables.

Effect of the internet commerce on dispersal modes of invasive alien species.

Science.gov (United States)

Lenda, Magdalena; Skórka, Piotr; Knops, Johannes M H; Moroń, Dawid; Sutherland, William J; Kuszewska, Karolina; Woyciechowski, Michał

2014-01-01

The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal.

Effect of the internet commerce on dispersal modes of invasive alien species.

Directory of Open Access Journals (Sweden)

Magdalena Lenda

Full Text Available The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal.

Effect of the Internet Commerce on Dispersal Modes of Invasive Alien Species

Science.gov (United States)

Lenda, Magdalena; Skórka, Piotr; Knops, Johannes M. H.; Moroń, Dawid; Sutherland, William J.; Kuszewska, Karolina; Woyciechowski, Michał

2014-01-01

The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal. PMID:24932498

Lane-changing model with dynamic consideration of driver's propensity

Science.gov (United States)

Wang, Xiaoyuan; Wang, Jianqiang; Zhang, Jinglei; Ban, Xuegang Jeff

2015-07-01

Lane-changing is the driver's selection result of the satisfaction degree in different lane driving conditions. There are many different factors influencing lane-changing behavior, such as diversity, randomicity and difficulty of measurement. So it is hard to accurately reflect the uncertainty of drivers' lane-changing behavior. As a result, the research of lane-changing models is behind that of car-following models. Driver's propensity is her/his emotion state or the corresponding preference of a decision or action toward the real objective traffic situations under the influence of various dynamic factors. It represents the psychological characteristics of the driver in the process of vehicle operation and movement. It is an important factor to influence lane-changing. In this paper, dynamic recognition of driver's propensity is considered during simulation based on its time-varying discipline and the analysis of the driver's psycho-physic characteristics. The Analytic Hierarchy Process (AHP) method is used to quantify the hierarchy of driver's dynamic lane-changing decision-making process, especially the influence of the propensity. The model is validated using real data. Test results show that the developed lane-changing model with the dynamic consideration of a driver's time-varying propensity and the AHP method are feasible and with improved accuracy.

Two new species of Commiphora (Burseraceae from southern Africa

Directory of Open Access Journals (Sweden)

W. Swanepoel

2006-08-01

Full Text Available Commiphora steynii Swanepoel and C.  gariepensis Swanepoel, here described as new species, are known only from the Kaokoveld and Gariep Centres of Endemism respectively. Illustrations of the plants and distribution maps are provided. Diagnostic characters of C.  steynii include the pale ashy grey, non-peeling bark and the lack of wart-like projections around the large lenticels. Diagnostic characters of C. gariepensis include the stamen number which varies between four and eight, and the milky-watery latex which does not squirt when branches are damaged. When without leaves or fruit, C. gariepensis can easily be confused with several other species. Comprehensive tables with diagnostic morphological features to distinguish between the new species and closely related taxa are presented.

Strains of the heterotrophic flagellate Bodo designis from different environments vary considerably with respect to salinity preference and SSU rRNA gene composition

DEFF Research Database (Denmark)

Koch, Trine A; Ekelund, Flemming

2005-01-01

The morpho species Bodo designis is widespread and abundant globally in highly contrasting terrestrial and aquatic ecosystems. Whether the forms of Bodo designis from contrasting environments are conspecific, i.e. largely genetically identical, or whether they merely share the external morphology...

Competitive intransitivity promotes species coexistence.

Science.gov (United States)

Laird, Robert A; Schamp, Brandon S

2006-08-01

Using a spatially explicit cellular automaton model with local competition, we investigate the potential for varied levels of competitive intransitivity (i.e., nonhierarchical competition) to promote species coexistence. As predicted, on average, increased levels of intransitivity result in more sustained coexistence within simulated communities, although the outcome of competition also becomes increasingly unpredictable. Interestingly, even a moderate degree of intransitivity within a community can promote coexistence, in terms of both the length of time until the first competitive exclusion and the number of species remaining in the community after 500 simulated generations. These results suggest that modest levels of intransitivity in nature, such as those that are thought to be characteristic of plant communities, can contribute to coexistence and, therefore, community-scale biodiversity. We explore a potential connection between competitive intransitivity and neutral theory, whereby competitive intransitivity may represent an important mechanism for "ecological equivalence."

Single-species versus dual-species probiotic supplementation as an emerging therapeutic strategy for obesity.

Science.gov (United States)

Karimi, G; Jamaluddin, R; Mohtarrudin, N; Ahmad, Z; Khazaai, H; Parvaneh, M

2017-10-01

Recent studies have reported beneficial effects of specific probiotics on obesity. However, the difference in the anti-obesity effects of probiotics as single species and dual species is still uncertain. Therefore, we aimed to compare the efficacy of single and dual species of bacteria on markers of obesity in high-fat diet-induced obese rats. A total of 40 male Sprague-Dawley rats were assigned to one of five groups of varying diets as follows: standard diet, high fat diet (HFD), HFD supplemented with Lactobacillus casei strain Shirota, HFD supplemented with Bifidobacterium longum and HFD supplemented with a mixture of these two bacterial species. After 15 weeks of supplementation, the animals were examined for changes in body weight, body fat, total count of bacteria in fecal, blood serum lipid profile, leptin, adiponectin and inflammatory biomarkers. Histological analysis of the liver and adipose tissue was performed and the hepatic mRNA expression levels of genes related to lipid metabolism were measured. It was found that probiotic supplementation of either B. longum or a mixture of B. longum and LcS bacteria significantly reduced weight and triglycerides in the HFD groups. Supplementation of B. longum bacteria showed better results in terms of modulating leptin level, fat mass, adipocyte size and lipoprotein lipase expression, as well as increasing adiponectin and peroxisome proliferator-activated receptors-γ expression compared to dual species of bacteria. No significant differences were observed in the total count of fecal bacteria, glucose and inflammatory biomarker levels between supplemented groups. B. longum supplementation in obesity was more beneficial in metabolic profile changes than the mixture species. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B

Floral nectary, nectar production dynamics and chemical composition in five nocturnal Oenothera species (Onagraceae) in relation to floral visitors.

Science.gov (United States)

Antoń, Sebastian; Komoń-Janczara, Elwira; Denisow, Bożena

2017-12-01

Main conclusion The floral nectars were sucrose-dominant; however, nectar protein and amino acid contents differed, indicating that composition of nitrogenous compounds may vary considerably even between closely related plant species, irrespectively of nectary structure. Numerous zoophilous plants attract their pollinators by offering floral nectar; an aqueous solution produced by specialized secretory tissues, known as floral nectaries. Although many papers on nectaries and nectar already exist, there has been a little research into the structure of nectaries and/or nectar production and composition in species belonging to the same genus. To redress this imbalance, we sought, in the present paper, to describe the floral nectary, nectar production, and nectar composition in five nocturnal Oenothera species with respect to their floral visitors. The structure of nectaries was similar for all the species investigated, and comprised the epidermis (with nectarostomata), numerous layers of nectary parenchyma, and subsecretory parenchyma. Anthesis for a single flower was short (ca. 10-12 h), and flowers lasted only one night. The release of floral nectar commenced at the bud stage (approx. 4 h before anthesis) and nectar was available to pollinators until petal closure. Nectar concentration was relatively low (ca. 27%) and the nectar was sucrose-dominant, and composed mainly of sucrose, glucose and fructose. The protein content of the nectar was also relatively low (on average, 0.31 µg ml -1 ). Nevertheless, a great variety of amino acids, including both protein and non-protein types, was detected in the nectar profile of the investigated taxa. We noted both diurnal and nocturnal generalist, opportunistic floral insect visitors.

Corruption, development and governance indicators predict invasive species risk from trade.

Science.gov (United States)

Brenton-Rule, Evan C; Barbieri, Rafael F; Lester, Philip J

2016-06-15

Invasive species have an enormous global impact, with international trade being the leading pathway for their introduction. Current multinational trade deals under negotiation will dramatically change trading partnerships and pathways. These changes have considerable potential to influence biological invasions and global biodiversity. Using a database of 47 328 interceptions spanning 10 years, we demonstrate how development and governance socio-economic indicators of trading partners can predict exotic species interceptions. For import pathways associated with vegetable material, a significantly higher risk of exotic species interceptions was associated with countries that are poorly regulated, have more forest cover and have surprisingly low corruption. Corruption and indicators such as political stability or adherence to rule of law were important in vehicle or timber import pathways. These results will be of considerable value to policy makers, primarily by shifting quarantine procedures to focus on countries of high risk based on their socio-economic status. Further, using New Zealand as an example, we demonstrate how a ninefold reduction in incursions could be achieved if socio-economic indicators were used to select trade partners. International trade deals that ignore governance and development indicators may facilitate introductions and biodiversity loss. Development and governance within countries clearly have biodiversity implications beyond borders. © 2016 The Author(s).

Oxidative stability and ignition quality of algae derived methyl esters containing varying levels of methyl eicosapentaenoate and methyl docosahexaenoate

Science.gov (United States)

Bucy, Harrison

Microalgae is currently receiving strong consideration as a potential biofuel feedstock to help meet the advanced biofuels mandate of the 2007 Energy Independence and Security Act because of its theoretically high yield (gallons/acre/year) in comparison to current terrestrial feedstocks. Additionally, microalgae also do not compete with food and can be cultivated with wastewater on non-arable land. Microalgae lipids can be converted into a variety of biofuels including fatty acid methyl esters (e.g. FAME biodiesel), renewable diesel, renewable gasoline, or jet fuel. For microalgae derived FAME, the fuel properties will be directly related to the fatty acid composition of the lipids produced by the given microalgae strain. Several microalgae species under consideration for wide scale cultivation, such as Nannochloropsis, produce lipids with fatty acid compositions containing substantially higher quantities of long chainpolyunsaturated fatty acids (LC-PUFA) in comparison to terrestrial feedstocks. It is expected that increased levels of LC-PUFA will be problematic in terms of meeting all of the current ASTM specifications for biodiesel. For example, it is known that oxidative stability and cetane number decrease with increasing levels of LC-PUFA. However, these same LC-PUFA fatty acids, such as eicosapentaenoic acid (EPA: C20:5) and docosahexaenoic acid (DHA: C22:6) are known to have high nutritional value thereby making separation of these compounds economically attractive. Given the uncertainty in the future value of these LC-PUFA compounds and the economic viability of the separation process, the goal of this study was to examine the oxidative stability and ignition quality of algae-based FAME with varying levels of EPA and DHA removal. Oxidative stability tests were conducted at a temperature of 110°C and airflow of 10 L/h using a Metrohm 743 Rancimat with automatic induction period determination following the EN 14112 Method from the ASTM D6751 and EN 14214

Forest Transpiration: Resolving Species-Specific Root Water Uptake Patterns

Science.gov (United States)

Blume, T.; Heidbuechel, I.; Simard, S.; Guntner, A.; Weiler, M.; Stewart, R. D.

2016-12-01

Transpiration and its spatio-temporal variability are still not fully understood, despite their importance for the global water cycle. This is in part due to our inability to measure transpiration comprehensively. Transpiration is usually either estimated with empirical equations based on climatic variables and crop factors, by measuring sap velocities, estimating sap wood area and scaling up to the forest stand based on a number of assumptions or by measuring the integral signal across a footprint with eddy flux towers. All these methods are focused on the cumulated loss of water to the atmosphere and do not provide information on where this water is coming from. In this study, spatio-temporal variability of root water uptake was investigated in a forest in the northeastern German lowlands. The soils are sandy and the depth of the unsaturated zone ranges from 1 to 30 m. We estimated root water uptake from different soil depths, from 0.1 m down to 2 m, based on diurnal fluctuations in soil moisture content during rain-free days. The 15 field sites cover different topographic positions and forest stands: 4 pure stands of both mature and young beech and pine and 9 mixed stands. The resulting daily data set of root water uptake shows that the forest stands differ in total amounts as well as in uptake depth distributions. Temporal dynamics of signal strength within the profile suggest a locally shifting spatial distribution of uptake that changes with water availability. The relationship of these depth-resolved uptake rates to overall soil water availability varies considerably between tree species. Using the physically-based soil hydrological model HYDRUS we investigated to what extent the observed patterns in uptake can be related to soil physical relationships alone and where tree species-specific aspects come into play. We furthermore used the model to test assumptions and estimate uncertainties of this soil moisture based estimation of plant water uptake. The

Does mixed-species flocking influence how birds respond to a gradient of land-use intensity?

Science.gov (United States)

Mammides, Christos; Chen, Jin; Goodale, Uromi Manage; Kotagama, Sarath Wimalabandara; Sidhu, Swati; Goodale, Eben

2015-07-22

Conservation biology is increasingly concerned with preserving interactions among species such as mutualisms in landscapes facing anthropogenic change. We investigated how one kind of mutualism, mixed-species bird flocks, influences the way in which birds respond to different habitat types of varying land-use intensity. We use data from a well-replicated, large-scale study in Sri Lanka and the Western Ghats of India, in which flocks were observed inside forest reserves, in 'buffer zones' of degraded forest or timber plantations, and in areas of intensive agriculture. We find flocks affected the responses of birds in three ways: (i) species with high propensity to flock were more sensitive to land use; (ii) different flock types, dominated by different flock leaders, varied in their sensitivity to land use and because following species have distinct preferences for leaders, this can have a cascading effect on followers' habitat selection; and (iii) those forest-interior species that remain outside of forests were found more inside flocks than would be expected by chance, as they may use flocks more in suboptimal habitat. We conclude that designing policies to protect flocks and their leading species may be an effective way to conserve multiple bird species in mixed forest and agricultural landscapes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

46 CFR 114.550 - Special consideration.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Special consideration. 114.550 Section 114.550 Shipping... consideration. In applying the provisions of this subchapter, the OCMI may give special consideration to... vessel operates must approve any special consideration granted to the vessel. ...

Restinga forests of the Brazilian coast: richness and abundance of tree species on different soils.

Science.gov (United States)

Magnago, Luiz F S; Martins, Sebastião V; Schaefer, Carlos E G R; Neri, Andreza V

2012-09-01

The aim of this study was to determine changes in composition, abundance and richness of species along a forest gradient with varying soils and flood regimes. The forests are located on the left bank of the lower Jucu River, in Jacarenema Natural Municipal Park, Espírito Santo. A survey of shrub/tree species was done in 80 plots, 5x25 m, equally distributed among the forests studied. We included in the sampling all individuals with >3.2 cm diameter at breast height (1.30 m). Soil samples were collected from the surface layer (0-10 cm) in each plot for chemical and physical analysis. The results indicate that a significant pedological gradient occurs, which is influenced by varying seasonal groundwater levels. Restinga forest formations showed significant differences in species richness, except for Non-flooded Forest and Non-flooded Forest Transition. The Canonical Correlation Analysis (CCA) showed that some species are distributed along the gradient under the combined influence of drainage, nutrient concentration and physical characteristics of the soil. Regarding the variables tested, flooding seems to be a more limiting factor for the establishment of plant species in Restinga forests than basic soil fertility attributes.

Diversity of hydraulic traits in nine Cordia species growing in tropical forests with contrasting precipitation.

Science.gov (United States)

Choat, Brendan; Sack, Lawren; Holbrook, N Michele

2007-01-01

Inter- and intraspecific variation in hydraulic traits was investigated in nine Cordia (Boraginaceae) species growing in three tropical rainforests differing in mean annual precipitation (MAP). Interspecific variation was examined for the different Cordia species found at each site, and intraspecific variation was studied in populations of the widespread species Cordia alliodora across the three sites. Strong intra- and interspecific variation were observed in vulnerability to drought-induced embolism. Species growing at drier sites were more resistant to embolism than those growing at moister sites; the same pattern was observed for populations of C. alliodora. By contrast, traits related to hydraulic capacity, including stem xylem vessel diameter, sapwood specific conductivity (K(s)) and leaf specific conductivity (K(L)), varied strongly but independently of MAP. For C. alliodora, xylem anatomy, K(s), K(L) and Huber value varied little across sites, with K(s) and K(L) being consistently high relative to other Cordia species. A constitutively high hydraulic capacity coupled with plastic or genotypic adjustment in vulnerability to embolism and leaf water relations would contribute to the ability of C. alliodora to establish and compete across a wide precipitation gradient.

Cross-scale modelling of alien and native vascular plant species richness in Great Britain: where is geodiversity information most relevant?

Science.gov (United States)

Bailey, Joseph; Field, Richard; Boyd, Doreen

2016-04-01

We assess the scale-dependency of the relationship between biodiversity and novel geodiversity information by studying spatial patterns of native and alien (archaeophytes and neophytes) vascular plant species richness at varying spatial scales across Great Britain. Instead of using a compound geodiversity metric, we study individual geodiversity components (GDCs) to advance our understanding of which aspects of 'geodiversity' are most important and at what scale. Terrestrial native (n = 1,490) and alien (n = 1,331) vascular plant species richness was modelled across the island of Great Britain at two grain sizes and several extent radii. Various GDCs (landforms, hydrology, geology) were compiled from existing national datasets and automatically extracted landform coverage information (e.g. hollows, valleys, peaks), the latter using a digital elevation model (DEM) and geomorphometric techniques. More traditional predictors of species richness (climate, widely-used topography metrics, land cover diversity, and human population) were also incorporated. Boosted Regression Tree (BRT) models were produced at all grain sizes and extents for each species group and the dominant predictors were assessed. Models with and without geodiversity data were compared. Overarching patterns indicated a clear dominance of geodiversity information at the smallest study extent (12.5km radius) and finest grain size (1x1km), which substantially decreased for each increase in extent as the contribution of climatic variables increased. The contribution of GDCs to biodiversity models was chiefly driven by landform information from geomorphometry, but hydrology (rivers and lakes), and to a lesser extent materials (soil, superficial deposits, and geology), were important, also. GDCs added significantly to vascular plant biodiversity models in Great Britain, independently of widely-used topographic metrics, particularly for native species. The wider consideration of geodiversity alongside

32 CFR 643.53 - Consideration.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Consideration. 643.53 Section 643.53 National... Leases § 643.53 Consideration. (a) Unless otherwise authorized by this regulation or directed by the SA, the consideration for a lease of real estate will be the appraised fair market rental value. However...

Invasive species in southern Nevada [Chapter 4] (Executive Summary)

Science.gov (United States)

Matthew L. Brooks; Steven M. Ostoja; Jeanne C.. Chambers

2013-01-01

Southern Nevada contains a wide range of topographies, elevations, and climatic zones that are emblematic of its position at the ecotone between the Mojave Desert, Great Basin, and Colorado Plateau ecoregions. These varied environmental conditions support a high degree of biological diversity, but they also provide opportunities for a wide range of invasive species. In...

28 CFR 51.34 - Expedited consideration.

Science.gov (United States)

2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Expedited consideration. 51.34 Section 51... consideration. (a) When a submitting authority is required under State law or local ordinance or otherwise finds... the submission be given expedited consideration. The submission should explain why such consideration...

Decision support systems for recovery of endangered species

International Nuclear Information System (INIS)

Armstrong, C.E.

1995-01-01

The listing of a species as endangered under the Endangered Species Act invokes a suite of responses to help improve conditions for the recovery of that species, to include identification of stressors contributing to population loss, decision analysis of the impacts of proposed recovery options, and implementation of optimal recovery measures. The ability of a decision support system to quantify inherent stressor uncertainties and to identify the key stressors that can be controlled or eliminated becomes key to ensuring the recovery of an endangered species. The listing of the Snake River sockeye, spring/summer chinook, and fall chinook salmon species in the Snake River as endangered provides a vivid example of the importance of sophisticated decision support systems. Operational and physical changes under consideration at eight of the hydroelectric dams along the Columbia and Lower Snake River pose significant financial impacts to a variety of stakeholders involved in the salmon population recovery process and carry significant uncertainties of outcome. A decision support system is presented to assist in the identification of optimal recovery actions for this example that includes the following: creation of datamarts of information on environmental, engineering, and ecological values that influence species survival; incorporation of decision analysis tools to determine optimal decision policies; and the use of geographic information systems (GIS) to provide a context for decision analysis and to communicate the impacts of decision policies

Rare Pediastrum species (Chlorophyceae from Polish coastal lakes

Directory of Open Access Journals (Sweden)

Joanna Kowalska

2011-01-01

Full Text Available An account is given of the occurrence of Pediastrum (Chlorophyceae, Sphaeropleales in five eutrophic coastal lakes (Jamno, Bukowo, Gardno, Łebsko and Sarbsko in northern Poland, together with morphological data of the species and more detailed taxonomic and ecological information for three taxa which appear to be rare world wide. These are P. musterii, P. orientale and P. alternans; the first is recorded for the first time from central Europe. P. orientale and P. alternans show considerable morphological variability under different environmental conditions, indicating the need for further studies. The studied lakes seem to be especially favourable for Pediastrum, with a total of eight species (15 taxa in the phytoplankton noted during the summer. However, the relative frequency of the genus in the overall algal communities was low. The most frequent species were P. boryanum, P. kawraiskyi and P. duplex and these were accompanied by cyanobacteria, coccal green algae (Chlorophyceae, Chlorococcales and diatoms (Bacillariophyceae. All the Pediastrum taxa were documented using LM and SEM.

Adaptive Immunity to Francisella tularensis and Considerations for Vaccine Development

Directory of Open Access Journals (Sweden)

Lydia M. Roberts

2018-04-01

Full Text Available Francisella tularensis is an intracellular bacterium that causes the disease tularemia. There are several subspecies of F. tularensis whose ability to cause disease varies in humans. The most virulent subspecies, tularensis, is a Tier One Select Agent and a potential bioweapon. Although considerable effort has made to generate efficacious tularemia vaccines, to date none have been licensed for use in the United States. Despite the lack of a tularemia vaccine, we have learned a great deal about the adaptive immune response the underlies protective immunity. Herein, we detail the animal models commonly used to study tularemia and their recapitulation of human disease, the field's current understanding of vaccine-mediated protection, and discuss the challenges associated with new vaccine development.

Modelling survival: exposure pattern, species sensitivity and uncertainty.

Science.gov (United States)

Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B; Van den Brink, Paul J; Veltman, Karin; Vogel, Sören; Zimmer, Elke I; Preuss, Thomas G

2016-07-06

The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.

Carnivorous sponges (Cladorhizidae) of the deep Weddell Sea, with descriptions of two new species

Science.gov (United States)

Dressler-Allame, Melina; Göcke, Christian; Kersken, Daniel; Plotkin, Alexander; Janussen, Dorte

2017-03-01

This paper presents 29 sponges of the family Cladorhizidae Dendy, 1922 sampled at 18 different stations in the Weddell Sea, Antarctic during two expeditions of RV Polarstern, PS61 ANT-XIX/2 ANDEEP 2 in 2002 and PS67 ANT-XXII/3 ANDEEP 3 in 2005. Fourteen species from four genera have been registered - one species of Asbestopluma Topsent, 1901, five species of Chondrocladia Thomson, 1873, three species of Cladorhiza Sars, 1872 and five species of Lycopodina Lundbeck, 1905. Six species are endemics of the Southern Ocean. Four species were previously only known from the areas north of the Antarctic and our records of them are thereby new for this region. Two species of Lycopodina, Lycopodina rhabdostylophora sp. nov. and Lycopodina pediculifera sp. nov., are new to science. Our study has considerably expanded the data on diversity of Cladorhizidae in the Southern Ocean. About 27 cladorhizid species (18-19% of global cladorhizid diversity) are now recorded for this region, of which 56% are endemics.

Oral bioaccessibility of toxic and essential elements in raw and cooked commercial seafood species available in European markets

KAUST Repository

Alves, Ricardo N.; Maulvault, Ana L.; Barbosa, Vera L.; Fernandez-Tejedor, Margarita; Tediosi, Alice; Kotterman, Michiel; van den Heuvel, Fredericus H.M.; Robbens, Johan; Fernandes, José O.; Romme Rasmussen, Rie; Sloth, Jens J.; Marques, Antó nio

2017-01-01

The oral bioaccessibility of several essential and toxic elements was investigated in raw and cooked commercially available seafood species from European markets. Bioaccessibility varied between seafood species and elements. Methylmercury bioaccessibility varied between 10 (octopus) and 60% (monkfish). Arsenic (>64%) was the toxic element showing the highest bioaccessibility. Concerning essential elements bioaccessibility in raw seafood, selenium (73%) and iodine (71%) revealed the highest percentages. The bioaccessibility of elements in steamed products increased or decreased according to species. For example, methylmercury bioaccessibility decreased significantly after steaming in all species, while zinc bioaccessibility increased in fish (tuna and plaice) but decreased in molluscs (mussel and octopus).Together with human exposure assessment and risk characterization, this study could contribute to the establishment of new maximum permissible concentrations for toxic elements in seafood by the European food safety authorities, as well as recommended intakes for essential elements.

Oral bioaccessibility of toxic and essential elements in raw and cooked commercial seafood species available in European markets

KAUST Repository

Alves, Ricardo N.

2017-11-17

The oral bioaccessibility of several essential and toxic elements was investigated in raw and cooked commercially available seafood species from European markets. Bioaccessibility varied between seafood species and elements. Methylmercury bioaccessibility varied between 10 (octopus) and 60% (monkfish). Arsenic (>64%) was the toxic element showing the highest bioaccessibility. Concerning essential elements bioaccessibility in raw seafood, selenium (73%) and iodine (71%) revealed the highest percentages. The bioaccessibility of elements in steamed products increased or decreased according to species. For example, methylmercury bioaccessibility decreased significantly after steaming in all species, while zinc bioaccessibility increased in fish (tuna and plaice) but decreased in molluscs (mussel and octopus).Together with human exposure assessment and risk characterization, this study could contribute to the establishment of new maximum permissible concentrations for toxic elements in seafood by the European food safety authorities, as well as recommended intakes for essential elements.

Relations pondérales entre l’encéphale et le corps chez les chiroptères. II. Espèces paléo-tropicales et paléarctiques. Discussion et conclusions

NARCIS (Netherlands)

Pirlot, Paul

1970-01-01

The ratio brain weight/body weight is studied in 30 species of bats from Asia, Africa and Europe, in comparison with 20 other species from South America dealt with in a previous paper. The simple encephalic ratios, expressed in o/oo, vary considerably and about between the same limits on the four

32 CFR 643.74 - Consideration.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Consideration. 643.74 Section 643.74 National... Licenses § 643.74 Consideration. When a license is granted under the authority of an easement or leasing statute, the same rules will apply in regard to consideration as is applicable to the granting of an...

Dynamic variation in sapwood specific conductivity in six woody species

Science.gov (United States)

Jean-Christophe Domec; Frederick C. Meinzer; Barbara Lachenbruch; Johann Housset

2008-01-01

Our goals were to quantify how non-embolism inducing pressure gradients influence trunk sapwood specific conductivity (ks) and to compare the impacts of constant and varying pressure gradients on ks with KCl and H20 as the perfusion solutions. We studied six woody species (three conifers and three...

Wide prevalence of hybridization in two sympatric grasshopper species may be shaped by their relative abundances.

Science.gov (United States)

Rohde, Katja; Hau, Yvonne; Weyer, Jessica; Hochkirch, Axel

2015-09-16

Hybridization between species is of conservation concern as it might threaten the genetic integrity of species. Anthropogenic factors can alter hybridization dynamics by introducing new potentially hybridizing species or by diminishing barriers to hybridization. This may even affect sympatric species pairs through environmental change, which so far has received little attention. We studied hybridization prevalence and the underlying behavioral mechanisms in two sympatric grasshopper species, a rare specialist (Chorthippus montanus) and a common generalist (Chorthippus parallelus). We conducted a mate choice experiment with constant intraspecific density and varying heterospecific density, i.e. varying relative frequency of both species. Mate choice was frequency-dependent in both species with a higher risk of cross-mating with increasing heterospecific frequency, while conspecific mating increased linearly with increasing conspecific density. This illustrates that reproductive barriers could be altered by environmental change, if the relative frequency of species pairs is affected. Moreover, we performed a microsatellite analysis to detect hybridization in twelve syntopic populations (and four allotopic populations). Hybrids were detected in nearly all syntopic populations with hybridization rates reaching up to 8.9 %. Genetic diversity increased for both species when hybrids were included in the data set, but only in the common species a positive correlation between hybridization rate and genetic diversity was detected. Our study illustrates that the relative frequency of the two species strongly determines the effectiveness of reproductive barriers and that even the more choosy species (Ch. montanus) may face a higher risk of hybridization if population size decreases and its relative frequency becomes low compared to its sister species. The asymmetric mate preferences of both species may lead to quasi-unidirectional gene flow caused by unidirectional

Germination sensitivity to water stress in four shrubby species across the Mediterranean Basin.

Science.gov (United States)

Chamorro, D; Luna, B; Ourcival, J-M; Kavgacı, A; Sirca, C; Mouillot, F; Arianoutsou, M; Moreno, J M

2017-01-01

Mediterranean shrublands are generally water-limited and fire-driven ecosystems. Seed-based post-fire regeneration may be affected by varying rainfall patterns, depending on species sensitivity to germinate under water stress. In our study, we considered the germination response to water stress in four species from several sites across the Mediterranean Basin. Seeds of species with a hard coat (Cistus monspeliensis, C. salviifolius, Cistaceae, Calicotome villosa, Fabaceae) or soft coat (Erica arborea, Ericaceae), which were exposed or not to a heat shock and smoke (fire cues), were made to germinate under water stress. Final germination percentage, germination speed and viability of seeds were recorded. Germination was modelled using hydrotime analysis and correlated to the water balance characteristics of seed provenance. Water stress was found to decrease final germination in the three hard-seeded species, as well as reduce germination speed. Moreover, an interaction between fire cues and water stress was found, whereby fire cues increased sensitivity to water stress. Seed viability after germination under water stress also declined in two hard-seeded species. Conversely, E. arborea showed little sensitivity to water stress, independent of fire cues. Germination responses varied among populations of all species, and hydrotime parameters were not correlated to site water balance, except in E. arborea when not exposed to fire cues. In conclusion, the species studied differed in germination sensitivity to water stress; furthermore, fire cues increased this sensitivity in the three hard-seeded species, but not in E. arborea. Moreover, populations within species consistently differed among themselves, but these differences could only be related to the provenance locality in E. arborea in seeds not exposed to fire cues. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Helminths of red foxes (Vulpes vulpes) in Denmark

DEFF Research Database (Denmark)

Saeed, I.; Maddox-Hyttel, Charlotte; Monrad, J.

2006-01-01

An epidemiological study of helminths in 1040 red foxes collected from various localities in Denmark during 1997-2002, revealed 21 helminth species at autopsy, including nine nematode species: Capillaria plica (prevalence 80.5%), Capillaria aerophila (74.1%), Crenosoma vulpis (17...... and average worm intensity for each helminth species varied considerably according to geographical locality, season, and year. Aggregated distribution was found for several helminth species. The two species E. multilocularis and E. perfoliatus are first records for Denmark....

EPANET Multi-Species Extension Software and User's Manual ...

Science.gov (United States)

Software and User's Manual EPANET is used in homeland security research to model contamination threats to water systems. Historically, EPANET has been limited to tracking the dynamics of a single chemical transported through a network of pipes and storage tanks, such as a fluoride used in a tracer study or free chlorine used in a disinfection decay study. Recently, the NHSRC released a new extension to EPANET called EPANET-MSX (Multi-Species eXtension) that allows for the consideration of multiple interacting species in the bulk flow and on the pipe walls. This capability has been incorporated into both a stand-alone executable program as well as a toolkit library of functions that programmers can use to build customized applications.

Zhang neural network for online solution of time-varying convex quadratic program subject to time-varying linear-equality constraints

International Nuclear Information System (INIS)

Zhang Yunong; Li Zhan

2009-01-01

In this Letter, by following Zhang et al.'s method, a recurrent neural network (termed as Zhang neural network, ZNN) is developed and analyzed for solving online the time-varying convex quadratic-programming problem subject to time-varying linear-equality constraints. Different from conventional gradient-based neural networks (GNN), such a ZNN model makes full use of the time-derivative information of time-varying coefficient. The resultant ZNN model is theoretically proved to have global exponential convergence to the time-varying theoretical optimal solution of the investigated time-varying convex quadratic program. Computer-simulation results further substantiate the effectiveness, efficiency and novelty of such ZNN model and method.

Predicting species distribution and abundance responses to climate change: why it is essential to include biotic interactions across trophic levels.

Science.gov (United States)

Van der Putten, Wim H; Macel, Mirka; Visser, Marcel E

2010-07-12

Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions. We review and synthesize literature information on biotic interactions and use it to argue that the abundance of species and the direction of selection during climate change vary depending on how their trophic interactions become disrupted. Plant abundance can be controlled by aboveground and belowground multitrophic level interactions with herbivores, pathogens, symbionts and their enemies. We discuss how these interactions may alter during climate change and the resulting species range shifts. We suggest conceptual analogies between species responses to climate warming and exotic species introduced in new ranges. There are also important differences: the herbivores, pathogens and mutualistic symbionts of range-expanding species and their enemies may co-migrate, and the continuous gene flow under climate warming can make adaptation in the expansion zone of range expanders different from that of cross-continental exotic species. We conclude that under climate change, results of altered species interactions may vary, ranging from species becoming rare to disproportionately abundant. Taking these possibilities into account will provide a new perspective on predicting species distribution under climate change.

The prevalence and distribution of Fusarium species in Norwegian cereals: a survey

DEFF Research Database (Denmark)

Kosiak, B.; Torp, M.; Skjerve, E.

2003-01-01

the regions. A total of 695 grain samples were analysed. The amount of Fusarium infection varied with cereal species and region of origin. The most frequently isolated Fusarium spp. from all samples were F. avenaceum, F. poae, F. tricinctum and F. culmorum. Other important toxigenic Fusarium spp. were F......In the period 1994-1996 a post-harvest survey was conducted in wheat, barley and oats to assess the occurrence and geographic distribution of Fusarium species in Norwegian cereals. The number of samples investigated was adjusted proportionally to the production of each cereal species within...... and F. culmorum demonstrated in this study , corresponded to previously reported DON-distribution, although DON seems to be produced by different species in different regions. Distribution of the isolated Fusarium species and comparison between cereals and locations are discussed....

Distribution and content of ellagitannins in Finnish plant species.

Science.gov (United States)

Moilanen, Johanna; Koskinen, Piia; Salminen, Juha-Pekka

2015-08-01

The results of a screening study, in which a total of 82 Finnish plant species were studied for their ellagitannin composition and content, are presented. The total ellagitannin content was determined by HPLC-DAD, the detected ellagitannins were further characterized by HPLC-ESI-QTOF-MS and divided into four structurally different sub-groups. Thirty plant species were found to contain ellagitannins and the ellagitannin content in the crude extracts varied from few mgg(-1) to over a hundred mgg(-1). Plant families that were rich in ellagitannins (>90mgg(-1) of the crude extract) were Onagraceae, Lyhtraceae, Geraniaceae, Elaeagnaceae, Fagaceae and some species from Rosaceae. Plant species that contained moderate amounts of ellagitannins (31-89mgg(-1) of the crude extract) were representatives of the family Rosaceae. Plant species that contained low amounts of ellagitannins (1-30mgg(-1) of the crude extract) were representatives of the families Betulaceae and Myricaceae. The specific ellagitannin composition of the species allowed their chemotaxonomic classification and the comparison between the older Cronquist's classification and the nowadays preferred Angiosperm Phylogeny Group classification. Copyright © 2015 Elsevier Ltd. All rights reserved.

Choosing the best animal species to mimic clinical colon anastomotic leakage in humans: a qualitative systematic review

DEFF Research Database (Denmark)

Pommergaard, Hans-Christian; Rosenberg, J; Schumacher-Petersen, Camilla

2011-01-01

Animal models are valuable for studying pathogenic factors and preventive measures for colon anastomotic leakage. The suitability of the species as models varies greatly; however, no consensus exists on which species to use. The aim of this review was to evaluate different experimental animals fo...

Watershed Management For Endangered Aquatic and Riparian Species: Facts and Fallacies

Science.gov (United States)

D.G. Neary; J.N. Rinne; A.L. Medina; M.B. Baker; J.L. Michael

2000-01-01

River basin management is becoming increasingly complex in the United States since watershed managers are required to take into consideration the threatened and endangered (T&E) species that inhabit aquatic and riparian ecosystems. Unfortunately too many fallacies and political agendas have crept into the picture. Suppositions and hypotheses fly everywhere in the...

Regional variation in Caribbean dry forest tree species composition

Science.gov (United States)

Janet Franklin; Julie Ripplinger; Ethan H. Freid; Humfredo Marcano-Vega; David W. Steadman

2015-01-01

How does tree species composition vary in relation to geographical and environmental gradients in a globally rare tropical/subtropical broadleaf dry forest community in the Caribbean? We analyzed data from 153 Forest Inventory and Analysis (FIA) plots from Puerto Rico and the U.S. Virgin Islands (USVI), along with 42 plots that we sampled in the Bahamian Archipelago (...

Primate social attention: Species differences and effects of individual experience in humans, great apes, and macaques

OpenAIRE

Kano, Fumihiro; Shepherd, Stephen V.; Hirata, Satoshi; Call, Josep

2018-01-01

When viewing social scenes, humans and nonhuman primates focus on particular features, such as the models’ eyes, mouth, and action targets. Previous studies reported that such viewing patterns vary significantly across individuals in humans, and also across closely-related primate species. However, the nature of these individual and species differences remains unclear, particularly among nonhuman primates. In large samples of human and nonhuman primates, we examined species differences and th...

Spacetime-varying couplings and Lorentz violation

International Nuclear Information System (INIS)

Kostelecky, V. Alan; Lehnert, Ralf; Perry, Malcolm J.

2003-01-01

Spacetime-varying coupling constants can be associated with violations of local Lorentz invariance and CPT symmetry. An analytical supergravity cosmology with a time-varying fine-structure constant provides an explicit example. Estimates are made for some experimental constraints

Birds on the move in the face of climate change: High species turnover in northern Europe.

Science.gov (United States)

Virkkala, Raimo; Lehikoinen, Aleksi

2017-10-01

Species richness is predicted to increase in the northern latitudes in the warming climate due to ranges of many southern species expanding northwards. We studied changes in the composition of the whole avifauna and in bird species richness in a period of already warming climate in Finland (in northern Europe) covering 1,100 km in south-north gradient across the boreal zone (over 300,000 km 2 ). We compared bird species richness and species-specific changes (for all 235 bird species that occur in Finland) in range size (number of squares occupied) and range shifts (measured as median of area of occupancy) based on bird atlas studies between 1974-1989 and 2006-2010. In addition, we tested how the habitat preference and migration strategy of species explain species-specific variation in the change of the range size. The study was carried out in 10 km squares with similar research intensity in both time periods. The species richness did not change significantly between the two time periods. The composition of the bird fauna, however, changed considerably with 37.0% of species showing an increase and 34.9% a decrease in the numbers of occupied squares, that is, about equal number of species gained and lost their range. Altogether 95.7% of all species (225/235) showed changes either in the numbers of occupied squares or they experienced a range shift (or both). The range size of archipelago birds increased and long-distance migrants declined significantly. Range loss observed in long-distance migrants is in line with the observed population declines of long-distance migrants in the whole Europe. The results show that there is an ongoing considerable species turnover due to climate change and due to land use and other direct human influence. High bird species turnover observed in northern Europe may also affect the functional diversity of species communities.

Seed and Germination Characteristics of 20 Amazonian Liana Species

Directory of Open Access Journals (Sweden)

Mareike Roeder

2013-01-01

Full Text Available Lianas are an important component of tropical forests, and may reach their highest densities in disturbed areas. However, information on seed and germination characteristics is scarce. Twenty Amazon liana species were screened for their germination characteristics, including light dependence, tolerance of desiccation and of alternating temperatures; these characteristics are considered important for the germination success in areas with relatively open canopies. Between 31–1,420 seeds per species were available, as 15 species seeds came from one mother plant. We studied seed biometry and conducted germination trials with fresh seeds (12 h light daily, or dark and desiccated seeds at 25 °C. Germination at alternating temperatures (20/30 °C, 15/35 °C was analyzed for nine species. Of the 20 species, eight species with the largest seeds had desiccation sensitive seeds; this is the first record for species of four genera and one family, where only desiccation tolerant seeds are otherwise recorded. Light-dependent germination was found in three species (0.01–0.015 g and is the first record for two; however, results were based on seeds from one plant per species. Alternating temperatures of 15/35 °C decreased final germination of four out of nine species, and response to 20/30 °C cycles varied compared to constant 25 °C. Seed and germination characteristics of the species ranged from pioneer to climax traits indicating that establishment of lianas from seeds may be confined to species specific niches.

Use of Animal Species Data in Environmental Impact Assessments

Science.gov (United States)

Knegtering, Edo; Drees, J. Marijke; Geertsema, Paul; Huitema, Hans J.; Uiterkamp, Anton J. M. Schoot

2005-12-01

Environmental Impact Assessments (EIAs) should ideally help minimize adverse effects on biological diversity by considering impacts of projects on wide ranges of species. This paper investigates how recent Dutch EIAs included the species comprising animal diversity. We present results of two studies on fauna data used in the EIAs. Objectives were to determine for different taxa (a) the relative representation of species in Environmental Impact Statements (EISs); (b) the extent to which EISs referred to specific species and the accuracy of survey data referred to; and (c) apparent roles of different EIA actors in species inclusion. EIAs were found to use data on various taxa but on limited numbers of species. The frequency with which taxa were included varied significantly. Birds were most frequently included, followed by mammals, amphibians, and other species groups. The quality of data on birds exceeded that regarding other vertebrates. Our results indicate that (a) EIA working groups of independent experts were the most influential in determining the data to be used; (b) on average, proponents included data more often than required by guidelines; and (c) in 30 to 40% of the EIAs, the participation of nongovernmental organizations prompted use of data. Despite the key role of experts in data inclusion, the taxon rankings found in the EIAs showed little deviation from those observed in studies on people’s preferences for species. Given the limited ranges of species considered, it is doubtful that the EIAs examined effectively contributed to conserving animal species diversity.

Feeding environment and other traits shape species' roles in marine food webs.

Science.gov (United States)

Cirtwill, Alyssa R; Eklöf, Anna

2018-04-02

Food webs and meso-scale motifs allow us to understand the structure of ecological communities and define species' roles within them. This species-level perspective on networks permits tests for relationships between species' traits and their patterns of direct and indirect interactions. Such relationships could allow us to predict food-web structure based on more easily obtained trait information. Here, we calculated the roles of species (as vectors of motif position frequencies) in six well-resolved marine food webs and identified the motif positions associated with the greatest variation in species' roles. We then tested whether the frequencies of these positions varied with species' traits. Despite the coarse-grained traits we used, our approach identified several strong associations between traits and motifs. Feeding environment was a key trait in our models and may shape species' roles by affecting encounter probabilities. Incorporating environment into future food-web models may improve predictions of an unknown network structure. © 2018 John Wiley & Sons Ltd/CNRS.

Natural infection of the sand fly Phlebotomus kazeruni by Trypanosoma species in Pakistan

Directory of Open Access Journals (Sweden)

Iwata Hiroyuki

2010-02-01

Full Text Available Abstract The natural infection of phlebotomine sand flies by Leishmania parasites was surveyed in a desert area of Pakistan where cutaneous leishmaniasis is endemic. Out of 220 female sand flies dissected, one sand fly, Phlebotomus kazeruni, was positive for flagellates in the hindgut. Analyses of cytochrome b (cyt b, glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH and small subunit ribosomal RNA (SSU rRNA gene sequences identified the parasite as a Trypanosoma species of probably a reptile or amphibian. This is the first report of phlebotomine sand flies naturally infected with a Trypanosoma species in Pakistan. The possible infection of sand flies with Trypanosoma species should be taken into consideration in epidemiological studies of vector species in areas where leishmaniasis is endemic.

Former land-use and tree species affect nitrogen oxide emissions from a tropical dry forest.

Science.gov (United States)

Heather Erickson; Eric A. Davidson; Michael Keller

2002-01-01

Species composition in successional dry forests in the tropics varies widely, but the effect of this variation on biogeochemical processes is not well known. We examined fluxes of N oxides (nitrous and nitric oxide), soil N cycling, and litter chemistry (C/N ratio) in four successional dry forests on similar soils in western Puerto Rico with differing species...

Genetic characterization, species differentiation and detection of Fasciola spp. by molecular approaches

Directory of Open Access Journals (Sweden)

Li Hai-Long

2011-06-01

Full Text Available Abstract Liver flukes belonging to the genus Fasciola are among the causes of foodborne diseases of parasitic etiology. These parasites cause significant public health problems and substantial economic losses to the livestock industry. Therefore, it is important to definitively characterize the Fasciola species. Current phenotypic techniques fail to reflect the full extent of the diversity of Fasciola spp. In this respect, the use of molecular techniques to identify and differentiate Fasciola spp. offer considerable advantages. The advent of a variety of molecular genetic techniques also provides a powerful method to elucidate many aspects of Fasciola biology, epidemiology, and genetics. However, the discriminatory power of these molecular methods varies, as does the speed and ease of performance and cost. There is a need for the development of new methods to identify the mechanisms underpinning the origin and maintenance of genetic variation within and among Fasciola populations. The increasing application of the current and new methods will yield a much improved understanding of Fasciola epidemiology and evolution as well as more effective means of parasite control. Herein, we provide an overview of the molecular techniques that are being used for the genetic characterization, detection and genotyping of Fasciola spp..

Estimating species richness and status of solitary bees and bumblebees in agricultural semi-natural habitats

DEFF Research Database (Denmark)

Calabuig, Isabel

2000-01-01

Estimation of Western Europe number of bee species varies between 2000 and 4500 (Williams 1995) but there are substantial indications of a decline in bee species in Europe and other regions. In Denmark, wild bee species richness, distribution, and abundance have not been studied in detail for about...... 75 years, and nothing is known about which species are potentially vulnerable or endangered. A rough estimate of solitary bees and bumblebees includes approximately 238 species (26 genera) and 29 species respectively. In a pan-trap survey of six kilometres of semi-natural habitats in a Danish...... agricultural landscape, 72 solitary bee species and 19 species of bumblebees were recorded, several of which are considered vulnerable or endangered in neighbouring countries. Nesting conditions for rare cavity-nesting species and the possible role of the semi-natural habitats as corridors for species...

The status of Botryosphaeriaceae species infecting grapevines

Directory of Open Access Journals (Sweden)

Jose Ramón URBEZ-TORRES

2011-12-01

Full Text Available Normal 0 MicrosoftInternetExplorer4 Normal 0 MicrosoftInternetExplorer4 Species in the Botryosphaeriaceae have a cosmopolitan distribution, and occur on a wide range of annual and perennial hosts including grapevines. To date, morphological and taxonomic studies, as well as analyses of nucleotide sequences of multiple genes, have allowed the identification of at least 21 different species in the Botryosphaeriaceae occurring in grapevines worldwide. Grapevine disease symptoms caused by members of this family include leaf spots, fruit rots, shoot dieback, bud necrosis, vascular discoloration of the wood, and perennial cankers, and their current status as pathogens is reviewed. Additionally, the disease name Botryosphaeria dieback is proposed here to describe the different grapevine trunk disease symptoms caused by species of Botryosphaeriaceae. Much has been written during the last decade about the association between species in the Botryosphaeriaceae and grapevine trunk diseases, which has contributed to a better understanding of the role that these fungal taxa play in grapevine diseases. Although virulence has been shown to vary between species and isolates of the same species in different countries, these fungi have become well-recognized as important grapevine pathogens worldwide. Latest and novel findings from studies conducted in different countries, on disease etiology and species distribution, epidemiology and biology are discussed. Much progress has been achieved in the development and implementation of novel diagnostic and detection techniques.Vineyard sanitation techniques, as well as chemical, biological, and cultural control strategies available at the present time to reduce the infection caused by botryosphaeriaceous fungi, are presented in this review. 

Nonlinear isochrones in murine left ventricular pressure-volume loops: how well does the time-varying elastance concept hold?

Science.gov (United States)

Claessens, T E; Georgakopoulos, D; Afanasyeva, M; Vermeersch, S J; Millar, H D; Stergiopulos, N; Westerhof, N; Verdonck, P R; Segers, P

2006-04-01

The linear time-varying elastance theory is frequently used to describe the change in ventricular stiffness during the cardiac cycle. The concept assumes that all isochrones (i.e., curves that connect pressure-volume data occurring at the same time) are linear and have a common volume intercept. Of specific interest is the steepest isochrone, the end-systolic pressure-volume relationship (ESPVR), of which the slope serves as an index for cardiac contractile function. Pressure-volume measurements, achieved with a combined pressure-conductance catheter in the left ventricle of 13 open-chest anesthetized mice, showed a marked curvilinearity of the isochrones. We therefore analyzed the shape of the isochrones by using six regression algorithms (two linear, two quadratic, and two logarithmic, each with a fixed or time-varying intercept) and discussed the consequences for the elastance concept. Our main observations were 1) the volume intercept varies considerably with time; 2) isochrones are equally well described by using quadratic or logarithmic regression; 3) linear regression with a fixed intercept shows poor correlation (R(2) volume intercept of the ESPVR. In conclusion, the linear time-varying elastance fails to provide a sufficiently robust model to account for changes in pressure and volume during the cardiac cycle in the mouse ventricle. A new framework accounting for the nonlinear shape of the isochrones needs to be developed.

Conservation assessments for five forest bat species in the Eastern United States

Science.gov (United States)

Frank R., III Thompson

2006-01-01

Assesses the status, distribution, conservation, and management considerations for five Regional Forester Sensitive Species of forest bats on national forests in the Eastern United States: eastern pipistrelle, evening bat, southeastern myotis, eastern small-footed myotis, and northern long-eared bat. Includes information on the taxonomy, description, life history,...

Evolution of perturbation in charge-varying dusty plasmas

International Nuclear Information System (INIS)

Popel, S.I.; Golub, A.P.; Losseva, T.V.; Bingham, R.; Benkadda, S.

2001-01-01

The nonstationary problem of the evolution of perturbation and its transformation into nonlinear wave structure in dusty plasmas is considered. For this purpose two one-dimensional models based on a set of fluid equations, Poisson's equation, and a charging equation for dust are developed. The first (simplified) model corresponds to the case [Popel et al., Phys. Plasmas 3, 4313 (1996)] when exact steady-state shock wave solutions can exist. This simplified model includes variable-charged dust grains, Boltzmann electrons, and inertial ions. The second (ionization source) model takes into account the variation of the ion density and the ion momentum dissipation due to dust particle charging as well as the source of plasma particles due to ionization process. The computational method for solving the set of equations which describe the evolution in time of a nonlinear structure in a charge-varying dusty plasma is developed. The case of the evolution of an intensive initial nonmoving region with a constant enhanced ion density is investigated on the basis of these two models. The consideration within the ionization source model is performed for the data of the laboratory experiment [Luo et al., Phys. Plasmas 6, 3455 (1999)]. It is shown that the ionization source model allows one to obtain shock structures as a result of evolution of an initial perturbation and to explain the experimental value of the width of the shock wave front. Comparison of the numerical data obtained on the basis of the ionization source model and the simplified model shows that the main characteristic features of the shock structure are the same for both models. Nevertheless, the ionization source model is much more sensitive to the form of the initial perturbation than the simplified model. The solution of the problem of the evolution of perturbation and its transformation into shock wave in charge-varying dusty plasmas opens up possibilities for description of the real phenomena like supernova

Petroleum hydrocarbon concentrations in ten commercial fish species along Tamilnadu coast, Bay of Bengal, India.

Science.gov (United States)

Veerasingam, S; Venkatachalapathy, R; Raja, P; Sudhakar, S; Rajeswari, V; Asanulla, R Mohamed; Mohan, R; Sutharsan, P

2011-05-01

The aim of the present study was to evaluate the distribution of petroleum hydrocarbons in ten commercial fish species and water samples in three estuaries along Tamilnadu coast, Bay of Bengal, India. Fish and water samples collected from Tamilnadu coast, India, were extracted and analyzed for petroleum hydrocarbons by ultraviolet fluorescence (UVF) spectroscopy. The petroleum hydrocarbon concentration (PHC) in coastal waters and fish species varied between 2.28 and 14.02 μg/l and 0.52 and 2.05 μg/g, respectively. The highest PHC concentration was obtained in Uppanar estuarine waters (14.02 ± 0.83) and the lowest was observed in Vellar estuarine waters (2.28 ± 0.25). Among the ten fish species, Sardinella longiceps have high PHC concentration from all the locations. This study suggests that S. longiceps can be used as a good biological indicator for petroleum hydrocarbon pollution in water. The concentration of petroleum hydrocarbons in coastal waters along Tamilnadu coast is markedly higher than that in the background, but there is no evidence for its increase in fish of this region. From a public health point, petroleum hydrocarbon residue levels in all fish samples analyzed in this study are considerably lower than the hazardous levels. At present, as Tamilnadu coastal area is in a rapid development stage of new harbour, chemical industries, power plants, oil exploration and other large-scale industries, further assessment of petroleum hydrocarbons and the various hydrodynamic conditions acting in the region are to be studied in detail and continuous pollution monitoring studies should be conducted for improving the aquatic environment. The results will also be useful for pollution monitoring program along the coastal region and also to check the levels of petroleum hydrocarbons.

Combined risk assessment of nonstationary monthly water quality based on Markov chain and time-varying copula.

Science.gov (United States)

Shi, Wei; Xia, Jun

2017-02-01

Water quality risk management is a global hot research linkage with the sustainable water resource development. Ammonium nitrogen (NH 3 -N) and permanganate index (COD Mn ) as the focus indicators in Huai River Basin, are selected to reveal their joint transition laws based on Markov theory. The time-varying moments model with either time or land cover index as explanatory variables is applied to build the time-varying marginal distributions of water quality time series. Time-varying copula model, which takes the non-stationarity in the marginal distribution and/or the time variation in dependence structure between water quality series into consideration, is constructed to describe a bivariate frequency analysis for NH 3 -N and COD Mn series at the same monitoring gauge. The larger first-order Markov joint transition probability indicates water quality state Class V w , Class IV and Class III will occur easily in the water body of Bengbu Sluice. Both marginal distribution and copula models are nonstationary, and the explanatory variable time yields better performance than land cover index in describing the non-stationarities in the marginal distributions. In modelling the dependence structure changes, time-varying copula has a better fitting performance than the copula with the constant or the time-trend dependence parameter. The largest synchronous encounter risk probability of NH 3 -N and COD Mn simultaneously reaching Class V is 50.61%, while the asynchronous encounter risk probability is largest when NH 3 -N and COD Mn is inferior to class V and class IV water quality standards, respectively.

A new species of Isoperla (Insecta, Plecoptera) from the Karawanken, with considerations on the Southern Limestone Alps as centers of endemism.

Science.gov (United States)

Graf, Wolfram; Konar, Martin; Murányi, Dávid; Orci, Kirill Márk; Vitecek, Simon

2014-01-01

A new species of the genus Isoperla (Plecoptera, Perlodidae), belonging to the oxylepis species-group is described, and the male mating call is characterized. Its range falls within a small region of the Southern Limestone Alps which is well known to be one endemism-centre of aquatic insects.

Comparison of antimicrobial susceptibilities of Corynebacterium species by broth microdilution and disk diffusion methods.

Science.gov (United States)

Weiss, K; Laverdière, M; Rivest, R

1996-01-01

Corynebacterium species are increasingly being implicated in foreign-body infections and in immunocompromised-host infections. However, there are no specific recommendations on the method or the criteria to use in order to determine the in vitro activities of the antibiotics commonly used to treat Corynebacterium infections. The first aim of our study was to compare the susceptibilities of various species of Corynebacterium to vancomycin, erythromycin, and penicillin by using a broth microdilution method and a disk diffusion method. Second, the activity of penicillin against our isolates was assessed by using the interpretative criteria recommended by the National Committee for Clinical Laboratory Standards for the determination of the susceptibility of streptococci and Listeria monocytogenes to penicillin. Overall, 100% of the isolates were susceptible to vancomycin, while considerable variations in the activities of erythromycin and penicillin were noted for the different species tested, including the non-Corynebacterium jeikeium species. A good correlation in the susceptibilities of vancomycin and erythromycin between the disk diffusion and the microdilution methods was observed. However, a 5% rate of major or very major errors was detected with the Listeria criteria, while a high rate of minor errors (18%) was noted when the streptococcus criteria were used. Our findings indicate considerable variations in the activities of erythromycin and penicillin against the various species of Corynebacterium. Because of the absence of definite recommendations, important discrepancies were observed between the methods and the interpretations of the penicillin activity. PMID:8849254

Retrospective analysis of diversity and species composition of marine macroalgae of Hainan Island (China)

Science.gov (United States)

Titlyanov, Eduard A.; Titlyanova, Tamara V.; Xia, Bangmei; Bartsch, Inka

2016-09-01

Retrospective analysis of diversity and species composition of marine macroalgae of Hainan Island in the period 1933-1992 is presented in this paper. There are two extensive sample collection periods of benthic macroalgae: the early collection (EC) covers a period between the early 1930s and the 1980s before considerable urbanization and reef degradation took place and a late collection (LC) was performed in 1990/1992 during a phase of rapid urbanization. Analysis of data also including an earlier published inventory of green algae covering the same collection sites (Titlyanov et al. 2011a) revealed that the marine flora of the island comprises 426 taxa in total, with 59% red algae, 18% brown algae and 23% green algae. In total 59 species of red algae, 11 species of brown algae and 37 species of green algae sampled during the LC are new records for Hainan Island. Considerable floristic changes between EC and LC became evident. In the LC there were significantly more filamentous, tubular or fine blade-like, and often epiphytic, green and red algae with a high surface-to-volume ratio. Additionally a reduction of green, brown and red algal species with larger fleshy or foliose thalli and a low surface-to-volume ratio was observed. It is assumed that the changes reflect the degradation of the coral reef ecosystem around Hainan, which was damaged by human activities especially in the 1950s-1970s.

Influence of soil pathogens on early regeneration success of tropical trees varies between forest edge and interior.

Science.gov (United States)

Krishnadas, Meghna; Comita, Liza S

2018-01-01

Soil fungi are key mediators of negative density-dependent mortality in seeds and seedlings, and the ability to withstand pathogens in the shaded understory of closed-canopy forests could reinforce light gradient partitioning by tree species. For four species of tropical rainforest trees-two shade-tolerant and two shade-intolerant-we conducted a field experiment to examine the interactive effects of fungal pathogens, light, and seed density on germination and early seedling establishment. In a fully factorial design, seeds were sown into 1 m 2 plots containing soil collected from underneath conspecific adult trees, with plots assigned to forest edge (high light) or shaded understory, high or low density, and fungicide or no fungicide application. We monitored total seed germination and final seedling survival over 15 weeks. Shade-intolerant species were strongly constrained by light; their seedlings survived only at the edge. Fungicide application significantly improved seedling emergence and/or survival for three of the four focal species. There were no significant interactions between fungicide and seed density, suggesting that pathogen spread with increased aggregation of seeds and seedlings did not contribute to pathogen-mediated mortality. Two species experienced significant edge-fungicide interactions, but fungicide effects in edge vs. interior forest varied with species and recruitment stage. Our results suggest that changes to plant-pathogen interactions could affect plant recruitment in human-impacted forests subject to fragmentation and edge-effects.

A new species of Isoperla (Insecta, Plecoptera from the Karawanken, with considerations on the Southern Limestone Alps as centers of endemism

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Wolfram Graf

2014-10-01

Full Text Available A new species of the genus Isoperla (Plecoptera, Perlodidae, belonging to the oxylepis species-group is described, and the male mating call is characterized. Its range falls within a small region of the Southern Limestone Alps which is well known to be one endemism-centre of aquatic insects.

Functional diversity measures revealed impacts of non-native species and habitat degradation on species-poor freshwater fish assemblages.

Science.gov (United States)

Colin, Nicole; Villéger, Sébastien; Wilkes, Martin; de Sostoa, Adolfo; Maceda-Veiga, Alberto

2018-06-01

Trait-based ecology has been developed for decades to infer ecosystem responses to stressors based on the functional structure of communities, yet its value in species-poor systems is largely unknown. Here, we used an extensive dataset in a Spanish region highly prone to non-native fish invasions (15 catchments, N=389 sites) to assess for the first time how species-poor communities respond to large-scale environmental gradients using a taxonomic and functional trait-based approach in riverine fish. We examined total species richness and three functional trait-based indices available when many sites have ≤3 species (specialization, FSpe; originality, FOri and entropy, FEnt). We assessed the responses of these taxonomic and functional indices along gradients of altitude, water pollution, physical habitat degradation and non-native fish biomass. Whilst species richness was relatively sensitive to spatial effects, functional diversity indices were responsive across natural and anthropogenic gradients. All four diversity measures declined with altitude but this decline was modulated by physical habitat degradation (richness, FSpe and FEnt) and the non-native:total fish biomass ratio (FSpe and FOri) in ways that varied between indices. Furthermore, FSpe and FOri were significantly correlated with Total Nitrogen. Non-native fish were a major component of the taxonomic and functional structure of fish communities, raising concerns about potential misdiagnosis between invaded and environmentally-degraded river reaches. Such misdiagnosis was evident in a regional fish index widely used in official monitoring programs. We recommend the application of FSpe and FOri to extensive datasets from monitoring programs in order to generate valuable cross-system information about the impacts of non-native species and habitat degradation, even in species-poor systems. Scoring non-native species apart from habitat degradation in the indices used to determine ecosystem health is

Vertical distribution and migration of euphausiid species in the Red Sea

KAUST Repository

Wiebe, Peter H.

2016-06-01

We addressed how the extreme environmental conditions of the Red Sea impact or alter patterns of vertical distribution and vertical migration of five euphausiid species that are known from other oceans. Euphausia diomedeae was abundant and performed diel vertical migration (DVM) from >200 m in daytime to <100 m at night, similar to its pattern in other ocean regions. Euphausia sibogae and Euphausia sanzoi also showed consistent patterns of DVM across their ranges in the Red Sea and elsewhere. Two species, Stylocheiron affine and Stylocheiron abbreviatum, did not exhibit DVM. DNA barcode sequences for mitochondrial cytochrome oxidase I (COI) were used to confirm species identifications for four species (no previous barcode data exist for E. sanzoi). COI sequence differences averaged 2.8% (SD 3.1%) within species and 16.6% (SD 0.7%) between species, similar to previous studies of euphausiids. Red Sea specimens of S. affine matched morphological descriptions of a western equatorial form and differed 14% from Atlantic and Pacific specimens, suggesting possible cryptic species-level variation within this taxon. Widely distributed species of zooplankton may exhibit broad tolerance ranges for key environmental variables, and have considerable potential to adapt to variable and changing conditions across their geographic range.

Variation in levels of reactive oxygen species is explained by maternal identity, sex and body-size-corrected clutch size in a lizard

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Olsson, Mats; Wilson, Mark; Uller, Tobias; Mott, Beth; Isaksson, Caroline

2009-01-01

Many organisms show differences between males and females in growth rate and crucial life history parameters, such as longevity. Considering this, we may expect levels of toxic metabolic by-products of the respiratory chain, such as reactive oxygen species (ROS), to vary with age and sex. Here, we analyse ROS levels in female Australian painted dragon lizards ( Ctenophorus pictus) and their offspring using fluorescent probes and flow cytometry. Basal level of four ROS species (singlet oxygen, peroxynitrite, superoxide and H2O2) measured with a combined marker, and superoxide measured specifically, varied significantly among families but not between the sexes. When blood cells from offspring were chemically encouraged to accelerate the electron transport chain by mitochondrial uncoupling, net superoxide levels were three times higher in daughters than sons (resulting in levels outside of the normal ROS range) and varied among mothers depending on offspring sex (significant interaction between maternal identity and offspring sex). In offspring, there were depressive effects on ROS of size-controlled relative clutch size, which relies directly on circulating levels of vitellogenin, a confirmed antioxidant in some species. Thus, levels of reactive oxygen species varies among females, offspring and in relation to reproductive investment in a manner that makes its regulatory processes likely targets of selection.

A new species of Speonemadus from Portugal, with the revision of the escalerai-group (Coleoptera, Leiodidae

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Ana Sofia P.S. Reboleira

2017-01-01

Full Text Available Over recent years, intense field work in caves of Portugal has provided new data on the distribution of subterranean Iberian leiodid beetles. Speonemadus algarvensis sp. nov. is described from caves of southern Portugal. The new species is included in the Speonemadus Jeannel, 1922 escalerai-group (Cholevinae; Anemadini. All species of the S. escalerai-group are revised and S. breuili (Jeannel, 1922 is resurrected as a valid species. A key to identify the species of the S. escalerai-group is provided and the distinctive characters are illustrated. The distribution of all species of the group is mapped with new data together with biogeographic considerations.

Threatened plant species of the Nevada Test Site, Ash Meadows, central-southern Nevada

Energy Technology Data Exchange (ETDEWEB)

Beatley, J.C.

1977-04-01

This report is a companion one to Endangered Plant Species of the Nevada Test Site, Ash Meadows, and Central-Southern Nevada (COO-2307-11) and deals with the threatened plant species of the same area. The species are those cited in the Federal Register, July 1, 1975, and include certain ones listed as occurring only in California or Arizona, but which occur also in central-southern Nevada. As with the earlier report, the purpose of this one is to record in detail the location of the past plant collections which constitute the sole or principal basis for defining the species' distributions and frequency of occurrence in southern Nye County, Nevada, and to recommend the area of the critical habitat where this is appropriate. Many of the species occur also in southern California, and for these the central-southern Nevada records are presented for consideration of the overall status of the species throughout its range.

Microbial accumulation of uranium, radium, and cesium

International Nuclear Information System (INIS)

Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.; North, S.E.

1981-05-01

Diverse microbial species varied considerably in their ability to accumulate uranium, cesium, and radium. Mechanistic differences in uranium uptake by Saccharomyces cerevisiae and Pseudomonas aeruginosa were indicated. S. serevisiae exhibited a slow (hours) surface accumulation of uranium which was subject to environmental factors, while P. aeruginosa accumulated uranium rapidly (minutes) as dense intracellular deposits and did not appear to be affected by environmental parameters. Metabolism was not required for uranium uptake by either organism. Cesium and radium were concentrated to a considerably lesser extent than uranium by the several species tested

Genetic interactions underlying hybrid male sterility in the Drosophila bipectinata species complex.

Science.gov (United States)

Mishra, Paras Kumar; Singh, Bashisth Narayan

2006-06-01

Understanding genetic mechanisms underlying hybrid male sterility is one of the most challenging problems in evolutionary biology especially speciation. By using the interspecific hybridization method roles of Y chromosome, Major Hybrid Sterility (MHS) genes and cytoplasm in sterility of hybrid males have been investigated in a promising group, the Drosophila bipectinata species complex that consists of four closely related species: D. pseudoananassae, D. bipectinata, D. parabipectinata and D. malerkotliana. The interspecific introgression analyses show that neither cytoplasm nor MHS genes are involved but X-Y interactions may be playing major role in hybrid male sterility between D. pseudoananassae and the other three species. The results of interspecific introgression analyses also show considerable decrease in the number of males in the backcross offspring and all males have atrophied testes. There is a significant positive correlation between sex - ratio distortion and severity of sterility in backcross males. These findings provide evidence that D. pseudoananassae is remotely related with other three species of the D. bipectinata species complex.

Accounting for complementarity to maximize monitoring power for species management.

Science.gov (United States)

Tulloch, Ayesha I T; Chadès, Iadine; Possingham, Hugh P

2013-10-01

To choose among conservation actions that may benefit many species, managers need to monitor the consequences of those actions. Decisions about which species to monitor from a suite of different species being managed are hindered by natural variability in populations and uncertainty in several factors: the ability of the monitoring to detect a change, the likelihood of the management action being successful for a species, and how representative species are of one another. However, the literature provides little guidance about how to account for these uncertainties when deciding which species to monitor to determine whether the management actions are delivering outcomes. We devised an approach that applies decision science and selects the best complementary suite of species to monitor to meet specific conservation objectives. We created an index for indicator selection that accounts for the likelihood of successfully detecting a real trend due to a management action and whether that signal provides information about other species. We illustrated the benefit of our approach by analyzing a monitoring program for invasive predator management aimed at recovering 14 native Australian mammals of conservation concern. Our method selected the species that provided more monitoring power at lower cost relative to the current strategy and traditional approaches that consider only a subset of the important considerations. Our benefit function accounted for natural variability in species growth rates, uncertainty in the responses of species to the prescribed action, and how well species represent others. Monitoring programs that ignore uncertainty, likelihood of detecting change, and complementarity between species will be more costly and less efficient and may waste funding that could otherwise be used for management. © 2013 Society for Conservation Biology.

Effects of differential mobility on biased diffusion of two species

International Nuclear Information System (INIS)

Hipolito, R S; Zia, R K P; Schmittmann, B

2003-01-01

Using simulations and a simple mean-field theory, we investigate jamming transitions in a two-species lattice gas under non-equilibrium steady-state conditions. The two types of particles diffuse with different mobilities on a square lattice, subject to an excluded volume constraint and biased in opposite directions. Varying filling fraction, differential mobility and drive, we map out the phase diagram, identifying first order and continuous transitions between a free-flowing disordered and a spatially inhomogeneous jammed phase. Ordered structures are observed to drift, with a characteristic velocity, in the direction of the more mobile species

Passerine extrapair mating dynamics: a bayesian modeling approach comparing four species

NARCIS (Netherlands)

Brommer, J.E.; Alho, J.S.; Biard, C.; Chapman, J.R.; Charmantier, A.; Dreiss, A.; Hartley, I.R.; Hjernquist, M.B.; Kempenaers, B.; Komdeur, J.; Laaksonen, T.; Lehtonen, P.K.; Lubjuhn, T.; Patrick, S.C.; Rosivall, B.; Tinbergen, J.M.; Van der Velde, M.; Van Oers, K.; Wilk, T.; Winkel, W.

2010-01-01

In many socially monogamous animals, females engage in extrapair copulation (EPC), causing some broods to contain both within‐pair and extrapair young (EPY). The proportion of all young that are EPY varies across populations and species. Because an EPC that does not result in EPY leaves no forensic

Passerine Extrapair Mating Dynamics : A Bayesian Modeling Approach Comparing Four Species

NARCIS (Netherlands)

Brommer, Jon E.; Alho, Jussi S.; Biard, Clotilde; Chapman, Joanne R.; Charmantier, Anne; Dreiss, Amelie; Hartley, Ian R.; Hjernquist, Marten B.; Kempenaers, Bart; Komdeur, Jan; Laaksonen, Toni; Lehtonen, Paula K.; Lubjuhn, Thomas; Patrick, Samantha C.; Rosivall, Balazs; Tinbergen, Joost M.; van der Velde, Marco; van Oers, Kees; Wilk, Tomasz; Winkel, Wolfgang; Hjernquist, Mårten B.; Boughman, Janette; DeAngelis, Donald L.

In many socially monogamous animals, females engage in extrapair copulation (EPC), causing some broods to contain both within-pair and extrapair young (EPY). The proportion of all young that are EPY varies across populations and species. Because an EPC that does not result in EPY leaves no forensic

Seroprevalence of Hepatitis E Virus in Four Species of Parrots in China

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Xiao-Xuan Zhang, Nian-Zhang Zhang, Dong-Hui Zhou, Wei-Peng Tian, Ying-Tian Xu and Xing-Quan Zhu

2014-01-01

Full Text Available In this study, antibodies against avian Hepatitis E Virus (avian HEV were detected in 6.43% of examined serum samples (n=311 from budgerigars (Melopsittacus undulatus, lovebirds (Agapornis sp., cockatiel (Nymphicus hollandicus and Alexandrine parakeets (Psittacula eupatria by indirect ELISA. Seroprevalence of avian HEV infection in different parrot species varied from 0 to 7.92%. Statistical analysis of the origins of parrots demonstrated that parrots from Weifang city had a higher avian HEV seropositivity (7.84% compared with parrots from Beijing city (5.06%. The seroprevalence in parrots of different age groups varied from 4 to 7.62%. The avian HEV seroprevalence in parrots examined in spring and summer was 7.19 and 5.81%, respectively. This is the first report of avian HEV seroprevalence in four species of parrots in China, which will provide base-line data for the control of HEV infection in parrots in China.

Bird species turnover is related to changing predation risk along a vegetation gradient

Science.gov (United States)

LaManna, Joseph A.; Hemenway, Amy B.; Boccadori, Vanna; Martin, Thomas E.

2015-01-01

Turnover in animal species along vegetation gradients is often assumed to reflect adaptive habitat preferences that are narrower than the full gradient. Specifically, animals may decline in abundance where their reproductive success is low, and these poor-quality locations differ among species. Yet habitat use does not always appear adaptive. The crucial tests of how abundances and demographic costs of animals vary along experimentally manipulated vegetation gradients are lacking. We examined habitat use and nest predation rates for 16 bird species that exhibited turnover with shifts in deciduous and coniferous vegetation. For most bird species, decreasing abundance was associated with increasing predation rates along both natural and experimentally modified vegetation gradients. This landscape-scale approach strongly supports the idea that vegetation-mediated effects of predation are associated with animal distributions and species turnover.

Nucleosome-coupled expression differences in closely-related species

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Gebbia Marinella

2011-09-01

Full Text Available Abstract Background Genome-wide nucleosome occupancy is negatively related to the average level of transcription factor motif binding based on studies in yeast and several other model organisms. The degree to which nucleosome-motif interactions relate to phenotypic changes across species is, however, unknown. Results We address this challenge by generating nucleosome positioning and cell cycle expression data for Saccharomyces bayanus and show that differences in nucleosome occupancy reflect cell cycle expression divergence between two yeast species, S. bayanus and S. cerevisiae. Specifically, genes with nucleosome-depleted MBP1 motifs upstream of their coding sequence show periodic expression during the cell cycle, whereas genes with nucleosome-shielded motifs do not. In addition, conserved cell cycle regulatory motifs across these two species are more nucleosome-depleted compared to those that are not conserved, suggesting that the degree of conservation of regulatory sites varies, and is reflected by nucleosome occupancy patterns. Finally, many changes in cell cycle gene expression patterns across species can be correlated to changes in nucleosome occupancy on motifs (rather than to the presence or absence of motifs. Conclusions Our observations suggest that alteration of nucleosome occupancy is a previously uncharacterized feature related to the divergence of cell cycle expression between species.

Tree species effects on pathogen-suppressive capacities of soil bacteria across two tropical dry forests in Costa Rica.

Science.gov (United States)

Becklund, Kristen; Powers, Jennifer; Kinkel, Linda

2016-11-01

Antibiotic-producing bacteria in the genus Streptomyces can inhibit soil-borne plant pathogens, and have the potential to mediate the impacts of disease on plant communities. Little is known about how antibiotic production varies among soil communities in tropical forests, despite a long history of interest in the role of soil-borne pathogens in these ecosystems. Our objective was to determine how tree species and soils influence variation in antibiotic-mediated pathogen suppression among Streptomyces communities in two tropical dry forest sites (Santa Rosa and Palo Verde). We targeted tree species that co-occur in both sites and used a culture-based functional assay to quantify pathogen-suppressive capacities of Streptomyces communities beneath 50 focal trees. We also measured host-associated litter and soil element concentrations as potential mechanisms by which trees may influence soil microbes. Pathogen-suppressive capacities of Streptomyces communities varied within and among tree species, and inhibitory phenotypes were significantly related to soil and litter element concentrations. Average proportions of inhibitory Streptomyces in soils from the same tree species varied between 1.6 and 3.3-fold between sites. Densities and proportions of pathogen-suppressive bacteria were always higher in Santa Rosa than Palo Verde. Our results suggest that spatial heterogeneity in the potential for antibiotic-mediated disease suppression is shaped by tree species, site, and soil characteristics, which could have significant implications for understanding plant community composition and diversity in tropical dry forests.

Species composition, richness and nestedness of lizard assemblages from Restinga habitats along the brazilian coast.

Science.gov (United States)

Rocha, C F D; Vrcibradic, D; Kiefer, M C; Menezes, V A; Fontes, A F; Hatano, F H; Galdino, C A B; Bergallo, H G; Van Sluys, M

2014-05-01

Habitat fragmentation is well known to adversely affect species living in the remaining, relatively isolated, habitat patches, especially for those having small range size and low density. This negative effect has been critical in coastal resting habitats. We analysed the lizard composition and richness of restinga habitats in 16 restinga habitats encompassing three Brazilian states (Rio de Janeiro, Espírito Santo and Bahia) and more than 1500km of the Brazilian coast in order to evaluate if the loss of lizard species following habitat reduction occur in a nested pattern or at random, using the "Nestedness Temperature Calculator" to analyse the distribution pattern of lizard species among the restingas studied. We also estimated the potential capacity that each restinga has to maintain lizard species. Eleven lizard species were recorded in the restingas, although not all species occurred in all areas. The restinga with the richest lizard fauna was Guriri (eight species) whereas the restinga with the lowest richness was Praia do Sul (located at Ilha Grande, a large coastal island). Among the restingas analysed, Jurubatiba, Guriri, Maricá and Praia das Neves, were the most hospitable for lizards. The matrix community temperature of the lizard assemblages was 20.49° (= P restingas exhibited a considerable nested structure. The degree in which an area is hospitable for different assemblages could be used to suggest those with greater value of conservation. We concluded that lizard assemblages in coastal restingas occur at a considerable level of ordination in restinga habitats and that some restinga areas such as Jurubatiba, Guriri, Maricá and Praia das Neves are quite important to preserve lizard diversity of restinga environments.

Drivers for plant species diversity in a characteristic tropical forest landscape in Bangladesh

DEFF Research Database (Denmark)

Steinbauer, Manuel; Uddin, Mohammad Bela; Jentsch, Anke

2016-01-01

species richness and community composition along a land use intensity gradient in a forest landscape including tea gardens, tree plantations and nature reserves (Satchari Reserved Forest) based on multivariate approaches and variation partitioning. We find richness as well composition of tree...... and understory species to directly relate to a disturbance gradient that reflects protection status and elevation. This is astonishing, as the range in elevation is with 70 m really small. Topography and protection remain significant drivers of biodiversity after correcting for human disturbances. While tree...... and non-tree species richness were positively correlated, they differ considerably in their relation to other environmental or disturbance variables as well as in the spatial richness pattern. The disturbance regime particularly structures tree species richness and composition in protected areas. We...

Dynamic Seascapes Predict the Marine Occurrence of an Endangered Species

Science.gov (United States)

Breece, M.; Fox, D. A.; Dunton, K. J.; Frisk, M. G.; Jordaan, A.; Oliver, M. J.

2016-12-01

Landscapes are powerful environmental partitions that index complex biogeochemical processes that drive terrestrial species distributions. However, translating landscapes into seascapes requires that the dynamic nature of the fluid environment be reflected in spatial and temporal boundaries such that seascapes can be used in marine species distribution models and conservation decisions. A seascape product derived from satellite ocean color and sea surface temperature partitioned mid-Atlantic coastal waters on scales commensurate with the Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus coastal migration. The seascapes were then matched with acoustic telemetry records of Atlantic Sturgeon to determine seascape selectivity. To test our model, we used real-time satellite seascape maps to normalize the sampling of an autonomous underwater vehicle that resampled similar geographic regions with time varying seascape classifications. We found that Atlantic Sturgeon exhibited preference for one seascape class over those available in the coastal ocean, indicating selection for environmental properties that co-varied with the dynamic seascape class rather than geographical location. The recent listing of Atlantic Sturgeon as Endangered throughout much of their United States range has highlighted the need for improved understanding of their occurrence in marine waters to reduce interactions with various anthropogenic stressors. Narrow dynamic migration corridors may enable seascapes to be used as a daily decision tool by industry and managers to reduce interactions with this Endangered Species during coastal migrations.

Defensive behaviors of the Oriental armyworm Mythimna separata in response to different parasitoid species (Hymenoptera: Braconidae).

Science.gov (United States)

Zhou, Jincheng; Meng, Ling; Li, Baoping

2017-01-01

This study examined defensive behaviors of Mythimna separata (Lepidoptera: Noctuidae) larvae varying in body size in response to two parasitoids varying in oviposition behavior; Microplitis mediator females sting the host with the ovipositor after climbing onto it while Meteorus pulchricornis females make the sting by standing at a close distance from the host. Mythimna separata larvae exhibited evasive (escaping and dropping) and aggressive (thrashing) behaviors to defend themselves against parasitoids M. mediator and M. pulchricornis . Escaping and dropping did not change in probability with host body size or parasitoid species. Thrashing did not vary in frequency with host body size, yet performed more frequently in response to M. mediator than to M. pulchricornis . Parasitoid handling time and stinging likelihood varied depending not only on host body size but also on parasitoid species. Parasitoid handling time increased with host thrashing frequency, similar in slope for both parasitoids yet on a higher intercept for M. mediator than for M. pulchricornis . Handling time decreased with host size for M. pulchricornis but not for M. mediator . The likelihood of realizing an ovipositor sting decreased with thrashing frequency of both small and large hosts for M. pulchricornis , while this was true only for large hosts for M. mediator . Our results suggest that the thrashing behavior of M. separata larvae has a defensive effect on parasitism, depending on host body size and parasitoid species with different oviposition behaviors.

Defensive behaviors of the Oriental armyworm Mythimna separata in response to different parasitoid species (Hymenoptera: Braconidae

Directory of Open Access Journals (Sweden)

Jincheng Zhou

2017-08-01

Full Text Available This study examined defensive behaviors of Mythimna separata (Lepidoptera: Noctuidae larvae varying in body size in response to two parasitoids varying in oviposition behavior; Microplitis mediator females sting the host with the ovipositor after climbing onto it while Meteorus pulchricornis females make the sting by standing at a close distance from the host. Mythimna separata larvae exhibited evasive (escaping and dropping and aggressive (thrashing behaviors to defend themselves against parasitoids M. mediator and M. pulchricornis. Escaping and dropping did not change in probability with host body size or parasitoid species. Thrashing did not vary in frequency with host body size, yet performed more frequently in response to M. mediator than to M. pulchricornis. Parasitoid handling time and stinging likelihood varied depending not only on host body size but also on parasitoid species. Parasitoid handling time increased with host thrashing frequency, similar in slope for both parasitoids yet on a higher intercept for M. mediator than for M. pulchricornis. Handling time decreased with host size for M. pulchricornis but not for M. mediator. The likelihood of realizing an ovipositor sting decreased with thrashing frequency of both small and large hosts for M. pulchricornis, while this was true only for large hosts for M. mediator. Our results suggest that the thrashing behavior of M. separata larvae has a defensive effect on parasitism, depending on host body size and parasitoid species with different oviposition behaviors.

Patterns of infestation by the trombiculid mite Eutrombicula alfreddugesi in four sympatric lizard species (genus Tropidurus) in northeastern Brazil.

Science.gov (United States)

Rocha, C F D; Cunha-Barros, M; Menezes, V A; Fontes, A f; Vrcibradic, D; Van Sluys, M

2008-06-01

We studied the parasitism by the chigger mite Eutrombicula alfreddugesi on four sympatric lizard species of the genus Tropidurus in Morro do Chapéu, Bahia state, Brazil: T. hispidus, T. cocorobensis, T. semitaeniatus and T. erythrocephalus. For each species, we investigated the patterns of infestation and analyzed to which extent they varied among the hosts. We calculated the spatial niche breadth of the chigger mite on the body of each host species and the distribution of mites along the hosts' bodies for each Tropidurus species. All four species of Tropidurus at Morro do Chapéu were parasited by the chigger mite, with high (97-100%) prevalences. Host body size significantly explained the intensity of mite infestation for all species, except T. erythrocephalus. The body regions with highest intensity of infestation in the four lizard species were the mite pockets. The spacial niche width of the chigger varied consistently among the four lizards species studied being highest for T. erytrocephalus and lowest for T. cocorobensis. We conclude that the distribution and intensity with which lizards of the genus Tropidurus are infested by Eutrombicula alfreddugesi larvae results from the interaction between aspects of host morphology (such as body size and the occurrence and distribution of mite pockets) and ecology (especially microhabitat use).

Patterns of infestation by the trombiculid mite Eutrombicula alfreddugesi in four sympatric lizard species (genus Tropidurus in northeastern Brazil

Directory of Open Access Journals (Sweden)

Rocha C.F.D.

2008-06-01

Full Text Available We studied the parasitism by the chigger mite Eutrombicula alfreddugesi on four sympatric lizard species of the genus Tropidurus in Morro do Chapéu, Bahia state, Brazil: T. hispidus, T. cocorobensis, T. semitaeniatus and T. erythrocephalus. For each species, we investigated the patterns of infestation and analyzed to which extent they varied among the hosts. We calculated the spatial niche breadth of the chigger mite on the body of each host species and the distribution of mites along the hosts’ bodies for each Tropidurus species. All four species of Tropidurus at Morro do Chapéu were parasited by the chigger mite, with high (97-100% prevalences. Host body size significantly explained the intensity of mite infestation for all species, except T. erythrocephalus. The body regions with highest intensity of infestation in the four lizard species were the mite pockets. The spacial niche width of the chigger varied consistently among the four lizards species studied being highest for T. erytrocephalus and lowest for T. cocorobensis. We conclude that the distribution and intensity with which lizards of the genus Tropidurus are infested by Eutrombicula alfreddugesi larvae results from the interaction between aspects of host morphology (such as body size and the occurrence and distribution of mite pockets and ecology (especially microhabitat use.

New flux based dose–response relationships for ozone for European forest tree species

International Nuclear Information System (INIS)

Büker, P.; Feng, Z.; Uddling, J.; Briolat, A.; Alonso, R.; Braun, S.; Elvira, S.; Gerosa, G.; Karlsson, P.E.; Le Thiec, D.

2015-01-01

To derive O 3 dose–response relationships (DRR) for five European forest trees species and broadleaf deciduous and needleleaf tree plant functional types (PFTs), phytotoxic O 3 doses (PODy) were related to biomass reductions. PODy was calculated using a stomatal flux model with a range of cut-off thresholds (y) indicative of varying detoxification capacities. Linear regression analysis showed that DRR for PFT and individual tree species differed in their robustness. A simplified parameterisation of the flux model was tested and showed that for most non-Mediterranean tree species, this simplified model led to similarly robust DRR as compared to a species- and climate region-specific parameterisation. Experimentally induced soil water stress was not found to substantially reduce PODy, mainly due to the short duration of soil water stress periods. This study validates the stomatal O 3 flux concept and represents a step forward in predicting O 3 damage to forests in a spatially and temporally varying climate. - Highlights: • We present new ozone flux based dose–response relationships for European trees. • The model-based study accounted for the soil water effect on stomatal flux. • Different statistically derived ozone flux thresholds were applied. • Climate region specific parameterisation often outperformed simplified parameterisation. • Findings could help redefining critical levels for ozone effects on trees. - New stomatal flux based ozone dose–response relationships for tree species are derived for the regional risk assessment of ozone effects on European forest ecosystems.

Temperature-size responses match latitudinal-size clines in arthropods, revealing critical differences between aquatic and terrestrial species

DEFF Research Database (Denmark)

Horne, C.R.; Hirst, Andrew G.; Atkinson, D.

2015-01-01

of these gradients to date, and find that their direction and magnitude co-vary among 12 arthropod orders (r2 = 0.72). Body size in aquatic species generally reduces with both warming and decreasing latitude, whereas terrestrial species have much reduced and even opposite gradients. These patterns support...... the prediction that oxygen limitation is a major controlling factor in water, but not in air. Furthermore, voltinism explains much of the variation in T-S and L-S patterns in terrestrial but not aquatic species. While body size decreases with warming and with decreasing latitude in multivoltine terrestrial......Two major intraspecific patterns of adult size variation are plastic temperature-size (T-S) responses and latitude-size (L-S) clines. Yet, the degree to which these co-vary and share explanatory mechanisms has not been systematically evaluated. We present the largest quantitative comparison...

Application of the new keystone-species concept to prairie dogs: How well does it work?

Science.gov (United States)

Kotliar, N.B.

2000-01-01

It has been suggested that the keystone-species concept should be dropped from ecology and conservation, primarily because the concept is poorly defined. This prompted Power et al. (1996) to refine the definition: keystone species have large effects on community structure or ecosystem function (i.e., high overall importance), and this effect should be large relative to abundance (i.e., high community importance). Using prairie dogs (Cynomys spp.) as an example, I review operational and conceptual difficulties encountered in applying this definition. As applied to prairie dogs, the implicit assumption that overall importance is a linear function of abundance is invalid. In addition, community importance is sensitive to abundance levels, the definition of community, and sampling scale. These problems arise largely from the equation for community importance, as used in conjunction with removal experiments at single abundance levels. I suggest that we shift from the current emphasis on the dualism between keystone and nonkeystone species and instead examine how overall and community importance vary (1) with abundance, (2) across spatial and temporal scales, and (3) under diverse ecological conditions. In addition, I propose that a third criterion be incorporated into the definition: keystone species perform roles not performed by other species or processes. Examination of how these factors vary among populations of keystone species should help identify the factors contributing to, or limiting, keystone-level functions, thereby increasing the usefulness of the keystone-species concept in ecology and conservation. Although the quantitative framework of Power et al. falls short of being fully operational, my conceptual guidelines may improve the usefulness of the keystone-species concept. Careful attention to the factors that limit keystone function will help avoid misplaced emphasis on keystone species at the expense of other species.

Distribution patterns of Saccharomyces species in cultural landscapes of Germany.

Science.gov (United States)

Brysch-Herzberg, Michael; Seidel, Martin

2017-08-01

The distribution patterns of the three Saccharomyces species, Saccharomyces paradoxus, S. uvarum and S. cerevisiae, were investigated by a culture-dependent approach in order to understand better how these species propagate in the cultural landscape of Germany. Saccharomyces paradoxus, the closest relative of S. cerevisiae, is shown to be a true woodland species. It was frequently found in the soil under conifers indicating that S. paradoxus is an autochthonous member of the microbial community in this habitat. Physiological characteristics of the species like the Crabtree effect and high tolerance against ethanol suggest that the species is adapted to regular supply with considerable amounts of sugars. Additionally, a high proportion of the S. paradoxus strains isolated in this study are shown to have the rare ability to ferment melezitose. For these reasons, it is hypothesized that S. paradoxus may be closely associated with the honeydew system in forests. Saccharomyces cerevisiae was rare in most habitats and only exceeded the frequency of S. paradoxus in habitats characterized by modern agricultural mass production of fruit. Both the landscape structure and the agricultural system heavily influence the frequencies of Saccharomyces species. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Raman Optical Activity and Raman Spectra of Amphetamine Species

DEFF Research Database (Denmark)

Berg, Rolf W.; Shim, Irene; White, Peter Cyril

2012-01-01

Theoretical calculations and preliminary measurements of vibrational Raman optical activity (ROA) spectra of different species of amphetamine (amphetamine and amphetamine-H+) are reported for the first time. The quantum chemical calculations were carried out as hybrid ab initio DFT-molecular orbi......Theoretical calculations and preliminary measurements of vibrational Raman optical activity (ROA) spectra of different species of amphetamine (amphetamine and amphetamine-H+) are reported for the first time. The quantum chemical calculations were carried out as hybrid ab initio DFT...... are employed for identification purposes. The DFT calculations show that the most stable conformations are those allowing for close contact between the aromatic ring and the amine hydrogen atoms. The internal rotational barrier within the same amphetamine enanti- omer has a considerable influence on the Raman...

Maternal, social and abiotic environmental effects on growth vary across life stages in a cooperative mammal.

Science.gov (United States)

English, Sinead; Bateman, Andrew W; Mares, Rafael; Ozgul, Arpat; Clutton-Brock, Tim H

2014-03-01

Resource availability plays a key role in driving variation in somatic growth and body condition, and the factors determining access to resources vary considerably across life stages. Parents and carers may exert important influences in early life, when individuals are nutritionally dependent, with abiotic environmental effects having stronger influences later in development as individuals forage independently. Most studies have measured specific factors influencing growth across development or have compared relative influences of different factors within specific life stages. Such studies may not capture whether early-life factors continue to have delayed effects at later stages, or whether social factors change when individuals become nutritionally independent and adults become competitors for, rather than providers of, food. Here, we examined variation in the influence of the abiotic, social and maternal environment on growth across life stages in a wild population of cooperatively breeding meerkats. Cooperatively breeding vertebrates are ideal for investigating environmental influences on growth. In addition to experiencing highly variable abiotic conditions, cooperative breeders are typified by heterogeneity both among breeders, with mothers varying in age and social status, and in the number of carers present. Recent rainfall had a consistently marked effect on growth across life stages, yet other seasonal terms only influenced growth during stages when individuals were growing fastest. Group size and maternal dominance status had positive effects on growth during the period of nutritional dependence on carers, but did not influence mass at emergence (at 1 month) or growth at independent stages (>4 months). Pups born to older mothers were lighter at 1 month of age and subsequently grew faster as subadults. Males grew faster than females during the juvenile and subadult stage only. Our findings demonstrate the complex ways in which the external environment

Chromosomal evolution of the Canidae. I. Species with high diploid numbers.

Science.gov (United States)

Wayne, R K; Nash, W G; O'Brien, S J

1987-01-01

The Giemsa banding patterns of seven canid species, including the grey wolf (Canis lupus), the maned wolf (Chrysocyon brachyurus), the bush dog (Speothos venaticus), the crab-eating fox (Cerdocyon thous), the grey fox (Urocyon cinereoargenteus), the bat-eared fox (Otocyon megalotis), and the fennec (Fennecus zerda), are presented and compared. Relative to other members of Canidae, these species have high diploid complements (2n greater than 64) consisting of largely acrocentric chromosomes. They show a considerable degree of chromosome homoeology, but relative to the grey wolf, each species is either missing chromosomes or has unique chromosomal additions and rearrangements. Differences in chromosome morphology among the seven species were used to reconstruct their phylogenetic history. The results suggest that the South American canids are closely related to each other and are derived from a wolf-like progenitor. The fennec and the bat-eared fox seem to be recent derivatives of a lineage that branched early from the wolf-like canids and which also includes the grey fox.

49 CFR 260.7 - Priority consideration.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Priority consideration. 260.7 Section 260.7... REHABILITATION AND IMPROVEMENT FINANCING PROGRAM Overview § 260.7 Priority consideration. When evaluating applications, the Administrator will give priority consideration (but not necessarily in the following order...

Do laboratory species protect endangered species? Interspecies variation in responses to 17β-estradiol, a model endocrine active compound

Science.gov (United States)

Jorgenson, Zachary G.; Buhl, Kevin J.; Bartell, Stephen E.; Schoenfuss, Heiko L.

2015-01-01

Rio Grande silvery minnow. However, this study supports the continued use of surrogate species for the beneficial implementation of water-quality regulations for the protection of threatened and endangered species if phylogenetic relationships are taken into consideration.

Do laboratory species protect endangered species? Interspecies variation in responses to 17β-estradiol, a model endocrine active compound.

Science.gov (United States)

Jorgenson, Z G; Buhl, K; Bartell, S E; Schoenfuss, H L

2015-01-01

Grande silvery minnow. However, this study supports the continued use of surrogate species for the beneficial implementation of water-quality regulations for the protection of threatened and endangered species if phylogenetic relationships are taken into consideration.

Do species conservation assessments capture genetic diversity?

Directory of Open Access Journals (Sweden)

Malin C. Rivers

2014-12-01

Full Text Available The best known system for classifying threat status of species, the IUCN Red List, currently lacks explicit considerations of genetic diversity, and consequently may not account for potential adaptation of species to future environmental change. To address this gap, we integrate range-wide genetic analysis with IUCN Red List assessments.We calculated the loss of genetic diversity under simulated range loss for species of Delonix (Leguminosae. Simulated range loss involved random loss of populations and was intended to model ongoing habitat destruction. We found a strong relationship between loss of genetic diversity and range. Moreover, we found correspondence between levels of genetic diversity and thresholds for ‘non-threatened’ versus ‘threatened’ IUCN Red List categories.Our results support the view that current threat thresholds of the IUCN Red List criteria reflect genetic diversity, and hence evolutionary potential; although the genetic diversity distinction between threatened categories was less evident. Thus, by supplementing conventional conservation assessments with genetic data, new insights into the biological robustness of IUCN Red List assessments for targeted conservation initiatives can be achieved. Keywords: Conservation assessment, Conservation genetics, Extinction risk, Genetic diversity, IUCN Red List, Range

Do North Atlantic eels show parallel patterns of spatially varying selection?

DEFF Research Database (Denmark)

Ulrik, Malene G.; Pujolar, Jose Martin; Ferchaud, Anne-Laure

2014-01-01

was used to genotype European eel individuals (glass eels) from 8 sampling locations across the species distribution. We tested for single-generation signatures of spatially varying selection in European eel by searching for elevated genetic differentiation using F-ST-based outlier tests and by testing...... for significant associations between allele frequencies and environmental variables. Results: We found signatures of possible selection at a total of 11 coding-gene SNPs. Candidate genes for local selection constituted mainly genes with a major role in metabolism as well as defense genes. Contrary to what has...... been found for American eel, only 2 SNPs in our study correlated with differences in temperature, which suggests that other explanatory variables may play a role. None of the genes found to be associated with explanatory variables in European eel showed any correlations with environmental factors...

Choosing the best animal species to mimic clinical colon anastomotic leakage in humans: a qualitative systematic review

DEFF Research Database (Denmark)

Pommergaard, H C; Rosenberg, J; Schumacher-Petersen, Camilla

2011-01-01

Animal models are valuable for studying pathogenic factors and preventive measures for colon anastomotic leakage. The suitability of the species as models varies greatly; however, no consensus exists on which species to use. The aim of this review was to evaluate different experimental animals...... for the study of clinical colon anastomotic leakage....

What Is the Predictive Value of Animal Models for Vaccine Efficacy in Humans? Consideration of Strategies to Improve the Value of Animal Models.

Science.gov (United States)

Herati, Ramin Sedaghat; Wherry, E John

2018-04-02

Animal models are an essential feature of the vaccine design toolkit. Although animal models have been invaluable in delineating the mechanisms of immune function, their precision in predicting how well specific vaccines work in humans is often suboptimal. There are, of course, many obvious species differences that may limit animal models from predicting all details of how a vaccine works in humans. However, careful consideration of which animal models may have limitations should also allow more accurate interpretations of animal model data and more accurate predictions of what is to be expected in clinical trials. In this article, we examine some of the considerations that might be relevant to cross-species extrapolation of vaccine-related immune responses for the prediction of how vaccines will perform in humans. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

Cross Shelf Patterns in Habitat Selectivity of Hawkfish (Family: Cirrhitidae) in the Red Sea; with a Special Case of Varying Color Morphs in Paracirrhites forsteri.

KAUST Repository

Chaidez, Veronica

2015-01-01

and between continental shelf positions. Cirrhitichthys oxycephalus only occurs at the reef slope and Cirrhitus spilotoceps is only found on reef crests. Paracirrhites forsteri was the most abundant species across all reefs and was found in four varying color

46 CFR 175.550 - Special consideration.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Special consideration. 175.550 Section 175.550 Shipping...) GENERAL PROVISIONS § 175.550 Special consideration. In applying the provisions of this subchapter, the OCMI may give special consideration to authorizing departures from the specific requirements when...

On four species of echinorhynchid acanthocephalans from marine fish in Halong Bay, Vietnam, including the description of three new species and a key to the species of Gorgorhynchus.

Science.gov (United States)

Amin, Omar M; Van Ha, Nguyen

2011-09-01

Four species of echinorhynchid acanthocephalans were collected from marine fish off Cat Ba Island, Halong Bay, Gulf of Tonkin, Vietnam, in the spring of 2009. Acanthocephalus halongensis n. sp. (Echinorhynchidae) from the redtail scad, Decapterus kurroides Bleeker 1855 (Carangidae), has a unique proboscis armature with a spiniform basal hook with lateral root and an incomplete receptacle wall posteriorly. Gorgorhynchus tonkinensis n. sp. (Rhadinorhynchidae) also from D. kurroides, has long, slender, winding lemnisci, many epidermal nuclei, and a narrow anterior trunk with a shoulder armed with 20 circles of tightly packed spines, the posterior four circles of which have abruptly larger spines than those in the anterior circles. Neorhadinorhynchus atypicalis n. sp. (Cavisomidae) from the rabbitfish, Siganus fuscescens (Houttuyn 1782) (Siganidae), has the largest number of proboscis hooks per row, testes wider than long, and four clustered cement glands. Micracanthorhynchica kuwaitensis Amin and Sey 1996 (Rhadinorhynchidae) from the spottail needlefish Strongylura strongylura (van Hasselt 1823) (Belonidae) was similar to specimens originally described from the Arabian Gulf off the Kuwaiti coast. These acanthocephalans were collected in small numbers but stood out as uniquely and considerably different from their closest relatives to warrant their reporting. All species of acanthocephalans and their host and geographic distribution are described, and a key to the species of Gorgorhynchus is provided.

Choosing preclinical study models of diabetic retinopathy: key problems for consideration

Science.gov (United States)

Mi, Xue-Song; Yuan, Ti-Fei; Ding, Yong; Zhong, Jing-Xiang; So, Kwok-Fai

2014-01-01

Diabetic retinopathy (DR) is the most common complication of diabetes mellitus in the eye. Although the clinical treatment for DR has already developed to a relative high level, there are still many urgent problems that need to be investigated in clinical and basic science. Currently, many in vivo animal models and in vitro culture systems have been applied to solve these problems. Many approaches have also been used to establish different DR models. However, till now, there has not been a single study model that can clearly and exactly mimic the developmental process of the human DR. Choosing the suitable model is important, not only for achieving our research goals smoothly, but also, to better match with different experimental proposals in the study. In this review, key problems for consideration in choosing study models of DR are discussed. These problems relate to clinical relevance, different approaches for establishing models, and choice of different species of animals as well as of the specific in vitro culture systems. Attending to these considerations will deepen the understanding on current study models and optimize the experimental design for the final goal of preventing DR. PMID:25429204

Spermiogenesis and spermatozoa ultrastructure in five species of the Curimatidae with some considerations on spermatozoal ultrastructure in the Characiformes

Directory of Open Access Journals (Sweden)

Irani Quagio-Grassiotto

Full Text Available Spermiogenesis in the curimatid species, Steindachnerina insculpta, Cyphocharax gillii, C. modestus, C. spilotus, and Potamorhina altamazonica, is characterized by lateral development of the flagellum, nuclear rotation, eccentric nuclear fossa formation, and chromatin compacted into thick fibers. These spermatozoa exhibit a spherical head containing a nucleus with the chromatin highly condensed into thick fibers with small electron-lucent areas, and no acrosome. The nuclear fossa is of the moderate type and eccentric and penetrated by the centriolar complex. The midpiece is small, has many elongate vesicles, and a short cytoplasmic channel. Mitochondria may be elongate, branched or C-shaped, and are separated from the initial segment of the axoneme by the cytoplasmic channel. The flagellum contains the classical axoneme structure (9+2 and has a membranous compartment in the initial region; it does not have lateral fins. Only small differences were observed among the analyzed species and genera of the Curimatidae. Spermiogenesis and spermatozoa in the Curimatidae have many of the characteristics found in almost all other characiform species. On the other hand, the presence of a membranous compartment in the initial region of curimatid flagella, a structure common in many Cypriniformes spermatozoa, is unknown in other characiforms. Spermiogenesis and the spermatozoa of the Characiformes are discussed.

The impact of the species-area relationship on estimates of paleodiversity.

Directory of Open Access Journals (Sweden)

2005-08-01

Full Text Available Estimates of paleodiversity patterns through time have relied on datasets that lump taxonomic occurrences from geographic areas of varying size per interval of time. In essence, such estimates assume that the species-area effect, whereby more species are recorded from larger geographic areas, is negligible for fossil data. We tested this assumption by using the newly developed Miocene Mammal Mapping Project database of western North American fossil mammals and its associated analysis tools to empirically determine the geographic area that contributed to species diversity counts in successive temporal bins. The results indicate that a species-area effect markedly influences counts of fossil species, just as variable spatial sampling influences diversity counts on the modern landscape. Removing this bias suggests some traditionally recognized peaks in paleodiversity are just artifacts of the species-area effect while others stand out as meriting further attention. This discovery means that there is great potential for refining existing time-series estimates of paleodiversity, and for using species-area relationships to more reliably understand the magnitude and timing of such biotically important events as extinction, lineage diversification, and long-term trends in ecological structure.

15 CFR 2301.5 - Special consideration.

Science.gov (United States)

2010-01-01

... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Special consideration. 2301.5 Section... PROGRAM Application Requirements § 2301.5 Special consideration. In accordance with section 392(f) of the Act, the Agency will give special consideration to applications that foster ownership of, operation of...

46 CFR 169.112 - Special consideration.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Special consideration. 169.112 Section 169.112 Shipping... Provisions § 169.112 Special consideration. In applying the provisions of this part, the Officer in Charge, Marine Inspection, may give special consideration to departures from the specific requirements when...

Vaccines for minor use and minor species (MUMS)--industry's views.

Science.gov (United States)

Bönisch, B

2004-01-01

Over the past 30 years the importance of vaccines for minor use and minor species has changed for multinational animal health companies. The major reasons for this are being reviewed, with a particular focus on technical, financial and business aspects. Key regulatory obstacles to the development of new products for minor uses and minor species are identified, and examples of vaccines falling into the various categories are provided. A number of proposals are offered with the intention of resolving the medicines availability problem between all the stakeholders involved. Finally, based on the presented scientific and regulatory considerations, ideas are shared as to where the legal and economical framework would need to change to reach a viable solution.

A new species of Rhytidognathus (Carabidae, Migadopini) from Argentina.

Science.gov (United States)

Roig-Juñent, Sergio; Rouaux, Julia

2012-01-01

The Migadopini are a small tribe of Carabidae with 47 species that occur in South America, Australia, and New Zealand, in the sub-Antarctic areas. In South America, most of the genera inhabit areas related to sub-Antartic Nothofagus forest except two monogeneric genera, the Ecuadorian genus Aquilex Moret and the Pampean genus Rhytidognathus Chaudoir. These two genera are geographically isolated from the remaining five South American genera. New material of Rhytidognathus from the northeast of Buenos Aires province and from Entre Ríos province permits establishing that the previous records of Rhytidognathus ovalis (Dejean) for Argentina were erroneous and that it belongs to a new species. Based on external morphological characters and from male and female genitalia we describe Rhytidognathus platensis as a new species. In this contribution we provide illustrations, keys, habitat characteristics and some biogeographic considerations on the distribution of Rhytidognathus.

A new species of Rhytidognathus (Carabidae, Migadopini from Argentina

Directory of Open Access Journals (Sweden)

Sergio Roig-Junent

2012-11-01

Full Text Available The Migadopini are a small tribe of Carabidae with 47 species that occur in South America, Australia, and New Zealand, in the sub-Antarctic areas. In South America, most of the genera inhabit areas related to sub-Antartic Nothofagus forest except two monogeneric genera, the Ecuadorian genus Aquilex Moret and the Pampean genus Rhytidognathus Chaudoir. These two genera are geographically isolated from the remaining five South American genera. New material of Rhytidognathus from the northeast of Buenos Aires province and from Entre Ríos province permits establishing that the previous records of Rhytidognathus ovalis (Dejean for Argentina were erroneous and that it belongs to a new species. Based on external morphological characters and from male and female genitalia we describe Rhytidognathus platensis as a new species. In this contribution we provide illustrations, keys, habitat characteristics and some biogeographic considerations on the distribution of Rhytidognathus.

Children's Brain Responses to Optic Flow Vary by Pattern Type and Motion Speed.

Directory of Open Access Journals (Sweden)

Rick O Gilmore

Full Text Available Structured patterns of global visual motion called optic flow provide crucial information about an observer's speed and direction of self-motion and about the geometry of the environment. Brain and behavioral responses to optic flow undergo considerable postnatal maturation, but relatively little brain imaging evidence describes the time course of development in motion processing systems in early to middle childhood, a time when psychophysical data suggest that there are changes in sensitivity. To fill this gap, electroencephalographic (EEG responses were recorded in 4- to 8-year-old children who viewed three time-varying optic flow patterns (translation, rotation, and radial expansion/contraction at three different speeds (2, 4, and 8 deg/s. Modulations of global motion coherence evoked coherent EEG responses at the first harmonic that differed by flow pattern and responses at the third harmonic and dot update rate that varied by speed. Pattern-related responses clustered over right lateral channels while speed-related responses clustered over midline channels. Both children and adults show widespread responses to modulations of motion coherence at the second harmonic that are not selective for pattern or speed. The results suggest that the developing brain segregates the processing of optic flow pattern from speed and that an adult-like pattern of neural responses to optic flow has begun to emerge by early to middle childhood.

Consideration Sets and Their Role in Modelling Doctor Recommendations About Contraceptives.

Science.gov (United States)

Fiebig, Denzil G; Viney, Rosalie; Knox, Stephanie; Haas, Marion; Street, Deborah J; Hole, Arne R; Weisberg, Edith; Bateson, Deborah

2017-01-01

Decisions about prescribed contraception are typically the result of a consultation between a woman and her doctor. In order to better understand contraceptive choice within this environment, stated preference methods are utilized to ask doctors about what contraceptive options they would discuss with different types of women. The role of doctors is to confine their discussion to a subset of products that best match their patient. This subset of options forms the consideration set from which the ultimate recommendation is made. Given the existence of consideration sets we address the issue of how to model appropriately the ultimate recommendations. The estimated models enable us to characterize doctor recommendations and how they vary with patient attributes and to highlight where recommendations are clear and when they are uncertain. The results also indicate systematic variation in recommendations across different types of doctors, and in particular we observe that some doctors are reluctant to embrace new products and instead recommend those that are more familiar. Such effects are one possible explanation for the relatively low uptake of more cost effective longer acting reversible contraceptives and indicate that further education and training of doctors may be warranted. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Passerine morphology: external measurements of approximately one-quarter of passerine bird species.

Science.gov (United States)

Ricklefs, Robert E

2017-05-01

Studies of community organization and clade diversification that include functional traits have become an important component of the analysis of ecological and evolved systems. Such studies frequently are limited by availability of consistently collected data. Here, I present a data set including eight measurements of the external morphology of 1642 species, roughly one-quarter of all passerine birds (Aves: Order Passeriformes), from all parts of the world, characterizing the relative proportions of the wing, tail, legs, and beak. Specimens were measured opportunistically over the past 40 years in museums in the United States and Europe. Numbers of individuals measured per species vary from one to dozens in some cases. Measurements for males and females of sexually size-dimorphic species are presented separately. The measurements include total length, the lengths of the wing, tail, tarsus, and middle toe, and the length, breadth, and depth of the beak. Particular attention was paid to obtaining a broad representation of passerine higher taxa, with special interest in small families and subfamilies of passerines, as well as species produced by evolutionary radiations of birds in archipelagoes, including the Galapagos, Hawaii, and the Lesser Antilles. Taxonomy follows the Taxonomy in Flux (TIF) checklist as well as the World Bird List of the International Ornithological Council. Geographic distributions are summarized from Edwards's Coded List of Birds of the World. Coverage of taxa and geographic regions varies and reflects the changing interests of the author over the past four decades. North American and South American species are particularly well represented in the sample, as well as species belonging to the families Tyrannidae, Furnariidae, Thamnophilidae, Mimidae, Sturnidae, Fringillidae, Parulidae, Icteridae, Cardinalidae, and Thraupidae. © 2017 by the Ecological Society of America.

Spatial correlation between weed species densities and soil properties

DEFF Research Database (Denmark)

Walter, Mette; Christensen, Svend; Simmelsgaard, Svend Erik

2002-01-01

The spatial cross-correlation between weed species densities and six soil properties within fields was analysed using cross-semivariograms. The survey was carried out in three successive years in two fields. The most consistent relationship between weed species density (numbers m−2) and soil...... properties was negative cross-correlation between the density of Viola arvensis Murray and clay content. This correlation was found in both fields; however, the range of spatial dependence varied between fields. In one of the fields, the density of Lamium purpureum L. was positively cross......-correlated with the phosphorus content in the soil in all years. The density of Veronica spp. and Poa annua L. was negatively cross-correlated with pH in all three years. Other spatial cross-correlations that were found in this study were inconsistent over time or field site. The densities of some of the weed species were...

Genetic variability in five species of Anostomidae (Ostariophysi - Characiformes

Directory of Open Access Journals (Sweden)

Chiari Lucimara

1999-01-01

Full Text Available Genetic variability was studied in five fish species (Anostomidae: Schizodon intermedius and S. nasutus and Leporinus friderici, L. elongatus and L. obtusidens, collected at one location on the Tibagi River (Paraná, Brazil. The protein data from seven systems coded collectively for 19 loci in the liver, muscle and heart. Nine of these loci were polymorphic. The estimated proportion of polymorphism loci ( varied from 16.7% in S. intermedius to 36.9% in L. friderici; the mean heterozygosity observed (o was 0.027 ± 0.015 and 0.109 ± 0.042, respectively. The estimated value of the genetic identity among L. friderici and S. intermedius (0.749 and S. nasutus (0.787 suggested that these are "congeneric" species. Morphological characteristics indicate that these species belong to distinct genera, while isoenzymatic data show that they are very similar at the genetic/biochemical level.

A comparative study on the emulsifying properties of various species of gum tragacanth.

Science.gov (United States)

Farzi, Mina; Emam-Djomeh, Zahra; Mohammadifar, Mohammad Amin

2013-06-01

Emulsification activities of three different species of gum tragacanth containing Astragalus gossypinus, A. compactus and A. rahensis were investigated. Emulsion stability indexes, particle size distributions, steady and unsteady rheological properties and some other physicochemical attributes including the surface tensions and uronic acid contents were taken into consideration. It was revealed that A. gossypinus created the most stable emulsions although having lower viscosity than A. compactus. It is believed that higher insoluble fraction and higher uronic content made this species a good steric and electrostatic emulsifier. Copyright © 2013 Elsevier B.V. All rights reserved.

The relative importance of intrinsic and extrinsic drivers to population growth vary among local populations of Greater Sage-Grouse: An integrated population modeling approach

Science.gov (United States)

Coates, Peter S.; Prochazka, Brian G.; Ricca, Mark A.; Halstead, Brian J.; Casazza, Michael L.; Blomberg, Erik J.; Brussee, Brianne E.; Wiechman, Lief; Tebbenkamp, Joel; Gardner, Scott C.; Reese, Kerry P.

2018-01-01

Consideration of ecological scale is fundamental to understanding and managing avian population growth and decline. Empirically driven models for population dynamics and demographic processes across multiple spatial scales can be powerful tools to help guide conservation actions. Integrated population models (IPMs) provide a framework for better parameter estimation by unifying multiple sources of data (e.g., count and demographic data). Hierarchical structure within such models that include random effects allow for varying degrees of data sharing across different spatiotemporal scales. We developed an IPM to investigate Greater Sage-Grouse (Centrocercus urophasianus) on the border of California and Nevada, known as the Bi-State Distinct Population Segment. Our analysis integrated 13 years of lek count data (n > 2,000) and intensive telemetry (VHF and GPS; n > 350 individuals) data across 6 subpopulations. Specifically, we identified the most parsimonious models among varying random effects and density-dependent terms for each population vital rate (e.g., nest survival). Using a joint likelihood process, we integrated the lek count data with the demographic models to estimate apparent abundance and refine vital rate parameter estimates. To investigate effects of climatic conditions, we extended the model to fit a precipitation covariate for instantaneous rate of change (r). At a metapopulation extent (i.e. Bi-State), annual population rate of change λ (er) did not favor an overall increasing or decreasing trend through the time series. However, annual changes in λ were driven by changes in precipitation (one-year lag effect). At subpopulation extents, we identified substantial variation in λ and demographic rates. One subpopulation clearly decoupled from the trend at the metapopulation extent and exhibited relatively high risk of extinction as a result of low egg fertility. These findings can inform localized, targeted management actions for specific areas

5 CFR 330.206 - Job consideration.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Job consideration. 330.206 Section 330..., SELECTION, AND PLACEMENT (GENERAL) Reemployment Priority List (RPL) § 330.206 Job consideration. (a)(1) An eligible employee under § 330.203 is entitled to consideration for positions in the commuting area for...

Chrysomelinae species (Coleoptera, Chrysomelidae) and new biological data from Rio de Janeiro, Brazil

Science.gov (United States)

Flinte, Vivian; Abejanella, André; Daccordi, Mauro; Monteiro, Ricardo F.; Macedo, Margarete Valverde

2017-01-01

Abstract Chrysomelinae is one of the largest subfamilies in Chrysomelidae, yet much basic information remains unknown for Neotropical species. The present study aims to compile the first regional list of Chrysomelinae for the State of Rio de Janeiro, Brazil, and assemble natural history traits obtained from our fieldwork from 2005 to 2010 in Serra dos Órgãos National Park, a mountainous area of Atlantic forest. The species list was compiled from data from field work, collections, and literature, and recorded a total of 100 species, belonging to 21 genera in one tribe (Chrysomelini) and three subtribes: Chrysolinina (91 species), Chrysomelina (eight species) and Entomoscelina (one species). Of these, 91 species are new records for the state. Serra dos Órgaõs National Park holds records of 43 species, with Platyphora being the most species-rich genus, and Solanaceae the most common host plant family. Some new records of reproductive mode (larviparous vs. oviparous) and larval behavior are also given. These Brazil Chrysomelinae species exhibited a clear seasonal pattern, with more species recorded in the hot and rainy season from October to January, and considerably fewer species from June to August, during the drier and colder months. The fraction of new records in comparison with published species and natural history information illustrates how little we know of Chrysomelinae in the state and in the country. PMID:29391849

Prices and species diversity

DEFF Research Database (Denmark)

Sauer, Johannes

of biodiversity and the appropriate incorporation in stochastic fron-tier models to achieve more realistic measures of production efficiency. We use the empirical example of tobacco production drawing from as well as affecting species diversity in the surrounding forests. We apply a shadow profit distance......In recent decades a significant amount of literature has been produced concerned with establishing a link between production efficiency and environmental efficiency with respect to quantitative modelling. This has been mainly addressed by focusing on the incorporation of undesirable outputs...... or the incorporation of environmentally det-rimental inputs. However, while the debate with respect to linear programming based DEA modelling is already at an advanced stage the corresponding one with respect to stochastic frontier modelling still needs considerable efforts. This contribution fo-cuses on the case...

Comparative study of lipids in mature seeds of six Cordia species (family Boraginaceae) collected in different regions of Brazil.

Science.gov (United States)

Carvalho, Patricía de O; Arrebola, Melissa B; Sawaya, Alexandra C H F; Cunha, Ildenize B S; Bastos, Deborah H M; Eberlin, Marcos N

2006-08-01

The oil content, FA, and lipid class composition of the mature seeds of six Cordia species were analyzed. Mature seeds of each species were collected in their natural habitat from 2002 to 2004. The total lipid content varied from 1.9% to 13.2%, there being significant differences between the results found in different years for each species and between the species analyzed. The contents of FFA varied from 2.0% to 7.9% of total lipids. Neutral lipids (NL) were the largest class, making up between 89.6% and 96.4% of the total lipids; the phospholipids (PL) were the second largest class (3.0% to 8.9% of the total lipids), and the glycolipids (GL) were the smallest class (0.6 to 3.4%). The presence of GLA was determined in each class of lipids; it is predominant in the NL. Levels of GLA ranged from 1.2% to 6.8% of total seed FA. This is, to our knowledge the first study of lipid composition in seeds of species of Cordia from Brazil.

ACCOUNTING FOR CONTINGENT CONSIDERATIONS IN BUSINESS COMBINATIONS

Directory of Open Access Journals (Sweden)

Gurgen KALASHYAN

2017-07-01

Full Text Available According to IFRS 3 Business Combinations contingent considerations must be included in the total consideration given for the acquired entity along with cash, other assets, ordinary or preference equity instruments, options, warrants. The contingent consideration is the determined amount which acquiring entity has to pay to acquired entity provided, that certain conditions will be fulfilled in the future. In case the provisions are not satisfied, we will get the situation when the amount of contingent consideration has been included in the total consideration given in the business combination, but in fact, the acquirer has not paid that amount. In its turn, the acquired entity will recognize the contingent consideration as a financial asset according to IFRS 9 Financial Instruments. In that case, it would be appropriately to recognize the contingent consideration as a contingent asset applying IAS 37. In the Article the author will explore the challenges of contingent consideration accounting and suggest the ways of solving the above mentioned problems.

MORPHOLOGIC CONSIDERATIONS ABOUT THE WALL OF THE GLANDULAR STOMACH OF YOUNG RABBITS (Oryctolagus cuniculus)

OpenAIRE

de Oliveira, Larissa Renata; Molinari, Sonia Lucy; Natali, Maria Raquel Marçal; Michelan, Andrea Cristiane; Scapinello, Claúdio

2001-01-01

The morphology of the stomach may vary between species as a function of feeding habits, differences on the cellular composition of the mucosa of the stomach wall and the different functions it carries out. Morphofunctional variations of the stomach of several animals along phylogeny led us to investigate the morphology of the wall of the glandular stomach of rabbits. We used the stomachs of 32 young rabbits (Oryctolagus cuniculus) from the White New Zealand strain, coming from the Experimenta...

Failed sperm development as a reproductive isolating barrier between species.

Science.gov (United States)

Wünsch, Lisa K; Pfennig, Karin S

2013-01-01

Hybrid male sterility is a common reproductive isolating barrier between species. Yet, little is known about the actual developmental causes of this phenomenon, especially in naturally hybridizing species. We sought to evaluate the developmental causes of hybrid male sterility, using spadefoot toads as our study system. Plains spadefoot toads (Spea bombifrons) and Mexican spadefoot toads (S. multiplicata) hybridize where they co-occur in the southwestern USA. Hybrids are viable, but hybrid males suffer reduced fertility. We compared testes size and developmental stages of sperm cell maturation between hybrid males and males of each species. We found that testes of hybrid males did not differ in mean size from pure-species males. However, hybrids showed a greater range of within-individual variation in testes size than pure-species males. Moreover, although hybrids produced similar numbers of early stage sperm cells, hybrids produced significantly fewer mature spermatozoids than pure-species males. Interestingly, an introgressed individual produced numbers of live sperm comparable to pure-species males, but the majority of these sperm cells were abnormally shaped and non-motile. These results indicate that hybrid incompatibilities in late sperm development serve as a reproductive isolating barrier between species. The nature of this breakdown highlights the possibilities that hybrid males may vary in fertility and that fertility could possibly be recovered in introgressed males. © 2013 Wiley Periodicals, Inc.

Determination of Germination Response to Temperature and Water Potential for a Wide Range of Cover Crop Species and Related Functional Groups.

Science.gov (United States)

Tribouillois, Hélène; Dürr, Carolyne; Demilly, Didier; Wagner, Marie-Hélène; Justes, Eric

2016-01-01

A wide range of species can be sown as cover crops during fallow periods to provide various ecosystem services. Plant establishment is a key stage, especially when sowing occurs in summer with high soil temperatures and low water availability. The aim of this study was to determine the response of germination to temperature and water potential for diverse cover crop species. Based on these characteristics, we developed contrasting functional groups that group species with the same germination ability, which may be useful to adapt species choice to climatic sowing conditions. Germination of 36 different species from six botanical families was measured in the laboratory at eight temperatures ranging from 4.5-43°C and at four water potentials. Final germination percentages, germination rate, cardinal temperatures, base temperature and base water potential were calculated for each species. Optimal temperatures varied from 21.3-37.2°C, maximum temperatures at which the species could germinate varied from 27.7-43.0°C and base water potentials varied from -0.1 to -2.6 MPa. Most cover crops were adapted to summer sowing with a relatively high mean optimal temperature for germination, but some Fabaceae species were more sensitive to high temperatures. Species mainly from Poaceae and Brassicaceae were the most resistant to water deficit and germinated under a low base water potential. Species were classified, independent of family, according to their ability to germinate under a range of temperatures and according to their base water potential in order to group species by functional germination groups. These groups may help in choosing the most adapted cover crop species to sow based on climatic conditions in order to favor plant establishment and the services provided by cover crops during fallow periods. Our data can also be useful as germination parameters in crop models to simulate the emergence of cover crops under different pedoclimatic conditions and crop

Life history affects how species experience succession in pen shell metacommunities.

Science.gov (United States)

Munguia, Pablo

2014-04-01

In nature, very few species are common and broadly distributed. Most species are rare and occupy few sites; this pattern is ubiquitous across habitats and taxa. In spatially structured communities (metacommunities), regional distribution and local abundance may change as the relative effects of within-habitat processes (e.g., species interactions) and among-habitat processes (e.g., dispersal) may vary through succession. A field experiment with the marine benthic inhabitants of pen shells (Atrina rigida) tested how common and rare species respond to succession and metacommunity size. I followed community development through time and partitioned species into sessile and motile based on their natural history. Rare species drive diversity patterns and are influenced by metacommunity size: there are strong abundance-distribution differences between common and rare species in large metacommunities, but motile species show lower rates of change than sessile species. In small metacommunities both common and rare species have similar changes through time; the dichotomous distinction of common and rare species is not present. Edge effects in metacommunities affect species' changes in distribution and abundance. In large metacommunities diversity is higher in edge habitats relative to small metacommunities during early succession. However, edge effects benefit motile species over time in small metacommunities showing a rapid increase in diversity. Individual mobility is sensitive to regional community size and allows individuals to sort among different communities. In contrast, sessile species do not show this edge effect. Metacommunity theory is a useful framework for understanding spatially structured communities, but the natural history of coexisting species cannot be ignored.