scholarly journals Observations of Tripsacum dactyloides and T. floridanum (Poaceae): measuring climate and soil gradient effects on Tripsacum in Texas, U.S.A.

2019 ◽  
Vol 13 (1) ◽  
pp. 355-365
Author(s):  
Gary McBryde
Keyword(s):  
Environmental Factors ◽  
Statistical Models ◽  
Tripsacum Dactyloides ◽  
Interspecies Competition ◽  
Conservation Implications ◽  
Simultaneous System ◽  
Plant Characteristics ◽  
Favorable Conditions ◽  
Gradient Effects ◽  
Soil Gradients

Reports of Tripsacum floridanum Porter ex Vasey in Texas have been countered with two arguments. First is that narrow-leafed Texas plants, when grown under favorable conditions, are more typical of wider-leafed T. dactyloides (L.) L. Second is that the offspring from crosses of T. dactyloides with T. floridanum are sterile or partially so. The support for these two claims is examined. The conclusion is narrow-leafed Texas plants typical of T. floridanum are in Texas, and crosses between the two produce fully fertile offspring. This raises the question of what factors are at play to segregate the wider-leafed from the narrower-leafed Texas populations. To investigate, two statistical models were constructed using separate data. First, a simultaneous system of seven equations was used to predict phenological and morphological plant characteristics given environmental factors. Second, a single logit equation predicted the probability of narrow-leafed diploid versus widerleafed diploid and tetraploid plants given environmental factors. Predictions allow for the measurement of plant characteristics from climate and soil gradients. Results suggest that narrow-leafed diploid plants occupy distinct habitats with the larger tetraploid plants coping by adapting mechanisms to overcome interspecies competition while the smaller diploid plants adapt with mechanisms to overcome stress. In conclusion, findings support consideration of T. floridanum as a variety of T. dactyloides and conservation implications are reviewed. 

scholarly journals FECUNDITY OF TREMATODES PARAFASCIOLOPSIS FASCIOLAEMORPHA IN THE NORTH OF THE NON-BLACK EARTH

2020 ◽  
pp. 223-228
Author(s):  
Maslennikova
Keyword(s):  
Environmental Factors ◽  
Definitive Host ◽  
Statistical Processing ◽  
The North ◽  
High Infection ◽  
Average Fecundity ◽  
Time Of Year ◽  
Favorable Conditions ◽  
Average Fertility ◽  
Abiotic Environmental Factors

High infection of moose with parafasciolopsosis in the North of the non-black earth region, reaching up to 75%, indicates favorable conditions for the circulation of the parasite in ecosystems, high biological pollution of the environment with eggs Parafasciolopsis fasciolaemorpha. The purpose of our study is to study the fecundity of P. fasciolaemorpha depending on the age of the definitive host and abiotic environmental factors (time of year). Fluke fecundity was determined by counting eggs in the uterus. We divided the invasive moose into 2 categories: young and adult, and the date of production was taken into account also. Fecundity was determined in 230 flukes. From fingerlings, 93 specimens were examined for the presence of eggs, from adult moose – 137 specimens of P. fasciolaemorpha. Statistical processing of the material was performed using EXCEL. The fecundity of the Parafasciolopsis fasciolaemorpha, which is an obligate parasite of moose, is relatively low and depends both on the age of the definitive host and on abiotic environmental factors (time of year). When parasitizing moose fingerlings, the average fertility of P. fasciolaemorpha reaches the highest values in the autumn months (30.1±2.17 copies), the lowest values – in the winter months (5.7±1.16). Fecundity of trematodes reaches maximum values when parasitizing in moose fingerlings – up to 45 eggs in the uterus, in adult moose – up to 25 eggs. The average fecundity of P. fasciolaemorpha marites that parasitize adult moose is 3 times lower than that of fingerlings. In autumn and spring, the fecundity of marites that parasitize adult moose increases to an average of 5.0–12.7 eggs in the winter months, trematodes are released from eggs and the average fecundity of P. fasciolaemorpha is 2.35–3.5 eggs. Low fecundity of trematodes is compensated by a high intensity of invasion.

scholarly journals Implication of environmental factors on the occurrence of pathogens in urban landscape ponds with reclaimed wastewater replenishment

2019 ◽  
Vol 1 (1) ◽  
pp. 119-133 ◽  
Author(s):  
Dong Ao ◽  
Yue Huang ◽  
Tao Xue ◽  
Nan Wang ◽  
Rong Chen
Keyword(s):  
Environmental Factors ◽  
Urban Landscape ◽  
Reclaimed Wastewater ◽  
Algae Bloom ◽  
Overlying Water ◽  
Viral Pathogens ◽  
Viral Pathogen ◽  
Chl A ◽  
One Year ◽  
Favorable Conditions

Abstract One year of continuous observation of bacterial and viral pathogen concentrations in overlying water and sediment of three urban landscape ponds replenished with reclaimed wastewater (RW) ponds was carried out to establish the distribution of pathogens and investigate the effects of environmental factors on that in RW ponds. The pathogens were represented by Escherichia coli and three common viral pathogens (enterovirus, norovirus, and rotavirus). Results indicated that the peak concentrations of pathogens occur from August to October. Pathogens present in sediment should be paid much more attention than those in overlying water, as they mainly contribute to the favorable conditions for survival and regrowth of pathogens in sediments. Cluster and redundancy analyses revealed that the environmental factors of chlorophyll a (Chl-a), organic matter, and water transparency have key impacts on the occurrence of pathogens. This infers that the practical way to reduce pathogenic risks in RW ponds is to control the algae bloom and improve the transparency of water bodies. Furthermore, based on breakpoint regression analyses, the appropriate ranges of Chl-a and transparency are suggested to be less than 57 mg/m3 and greater than 68 cm, respectively, to reduce the concentration of pathogens in urban landscape ponds replenished with RW.

scholarly journals Determining the Mechanisms that Influence the Surface Temperature of Urban Forest Canopies by Combining Remote Sensing Methods, Ground Observations, and Spatial Statistical Models

2018 ◽  
Vol 10 (11) ◽  
pp. 1814 ◽  
Author(s):  
Shudi Zuo ◽  
Shaoqing Dai ◽  
Xiaodong Song ◽  
Chengdong Xu ◽  
Yilan Liao ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Environmental Factors ◽  
Surface Temperature ◽  
Statistical Models ◽  
Land Surface ◽  
Urban Forest ◽  
Meteorological Data ◽  
Rapid Urbanization ◽  
Forest Canopies ◽  
Cold Spots

The spatiotemporal distribution pattern of the surface temperatures of urban forest canopies (STUFC) is influenced by many environmental factors, and the identification of interactions between these factors can improve simulations and predictions of spatial patterns of urban cool islands. This quantitative research uses an integrated method that combines remote sensing, ground surveys, and spatial statistical models to elucidate the mechanisms that influence the STUFC and considers the interaction of multiple environmental factors. This case study uses Jinjiang, China as a representative of a city experiencing rapid urbanization. We build up a multisource database (forest inventory, digital elevation models, population, and remote sensing imagery) on a uniform coordinate system to support research into the interactions that influence the STUFC. Landsat-5/8 Thermal Mapper images and meteorological data were used to retrieve the temporal and spatial distributions of land surface temperature. Ground observations, which included the forest management planning inventory and population density data, provided the factors that determine the STUFC spatial distribution on an urban scale. The use of a spatial statistical model (GeogDetector model) reveals the interaction mechanisms of STUFC. Although different environmental factors exert different influences on STUFC, in two periods with different hot spots and cold spots, the patch area and dominant tree species proved to be the main factors contributing to STUFC. The interaction between multiple environmental factors increased the STUFC, both linearly and nonlinearly. Strong interactions tended to occur between elevation and dominant species and were prevalent in either hot or cold spots in different years. In conclusion, the combining of multidisciplinary methods (e.g., remote sensing images, ground observations, and spatial statistical models) helps reveal the mechanism of STUFC on an urban scale.

Redroot Pigweed (Amaranthus retroflexus) Seed Germination Responses to Afterripening, Temperature, Ethylene, and Some Other Environmental Factors

Weed Science ◽  
1980 ◽  
Vol 28 (5) ◽  
pp. 543-548 ◽  
Author(s):  
Mark W. Schonbeck ◽  
Grant H. Egley
Keyword(s):  
Carbon Dioxide ◽  
Environmental Factors ◽  
Water Potential ◽  
Continuous Light ◽  
Potassium Nitrate ◽  
Amaranthus Retroflexus ◽  
Dry Storage ◽  
Redroot Pigweed ◽  
Carbon Dioxide Concentrations ◽  
Favorable Conditions

Germination responses of redroot pigweed (Amaranthus retroflexusL.) seeds to temperature, water potential, atmospheric ethylene and carbon dioxide concentrations, light, and nitrate ion were examined individually. Seeds kept in dry storage at −20 C and tested within 2 yr of harvest germinated at 35 C (12 to 25%) or 39.5 C (40 to 65%), but only 0 to 2% at 30 C and below. Germination at 35 C was prevented by water potentials below −4 bars. When seeds were kept in dry storage at 24 to 28 C, afterripening became evident within 2 months. After storage at this temperature for 4 yr, seeds showed 38% germination at 14 C, 40% at 35 C and −8 bars water potential, and over 90% under more favorable conditions. Ethylene (1 to 100 ppmv) or continuous light enhanced germination at 30 C regardless of degrees of afterripening, although the ethylene effect was most dramatic in nonafterripened seeds. Ethylene at 100 ppmv caused 40% germination in these seeds, compared to 1% for controls. Neither carbon dioxide (0.001 to 4.5% v/v) nor dissolved potassium nitrate (0.02 to 0.2% w/v) influenced germination. These results are discussed in relation to environmental factors influencing field emergence of redroot pigweed.

scholarly journals Habitat alteration enables hybridisation between Lesser Spotted and Greater Spotted Eagles in north-east Poland

2013 ◽  
Vol 24 (2) ◽  
pp. 152-161 ◽  
Author(s):  
GRZEGORZ MACIOROWSKI ◽  
PAWEŁ MIRSKI
Keyword(s):  
Environmental Factors ◽  
Habitat Preferences ◽  
Arable Land ◽  
Habitat Requirements ◽  
Habitat Alteration ◽  
Landscape Changes ◽  
Human Settlements ◽  
North East ◽  
Conservation Implications ◽  
Several Variables

SummaryWetlands in the Biebrza Valley, north-east Poland, are inhabited by two closely related Aquila species: the more numerous Lesser Spotted Eagle A. pomarina prefers human-transformed landscapes, whereas the very rare Greater Spotted Eagle A. clanga is associated with natural marshy landscapes. At least since the last decade of the 20th century, these two species have been known to hybridise in the broad zone of their sympatric occurrence in Europe. The aim of the present study was to compare habitat preferences of both spotted eagle species in order to detect which environmental factors could increase the probability of hybridisation. We analysed nesting and hunting habitats for 148 breeding territories (61 of A. pomarina, 56 of A. clanga and 31 of mixed pairs). As expected, the presence of breeding Greater Spotted Eagles was associated with non-transformed marshy landscapes, whereas Lesser Spotted Eagles clearly preferred human-transformed areas. We hypothesised that mixed pairs should occur in intermediate habitat, confirming this assumption by analysing several variables: distance to human settlements, distance to open areas, and proportion of wetlands, shrublands, grasslands, agricultural mosaic and arable land. Results of this study suggest that some landscape changes can enable two species with different habitat requirements to inhabit the same area and hybridise. This scenario has potential conservation implications for the rarer species, Greater Spotted Eagle, which has narrower habitat preferences.

Reductionist thinking and animal models in neuropsychiatric research

2019 ◽  
Vol 42 ◽  
Author(s):  
Nicole M. Baran
Keyword(s):  
Animal Models ◽  
Mental Disorders ◽  
Environmental Factors ◽  
Neuropsychiatric Disorders ◽  
Model Organisms ◽  
Developmental Genetic ◽  
Term Study ◽  
Genetic And Environmental Factors ◽  
Mechanisms Of Plasticity

AbstractReductionist thinking in neuroscience is manifest in the widespread use of animal models of neuropsychiatric disorders. Broader investigations of diverse behaviors in non-model organisms and longer-term study of the mechanisms of plasticity will yield fundamental insights into the neurobiological, developmental, genetic, and environmental factors contributing to the “massively multifactorial system networks” which go awry in mental disorders.

Mars: was There an Ancient Eden?

1997 ◽  
Vol 161 ◽  
pp. 203-218 ◽  
Author(s):  
Tobias C. Owen
Keyword(s):  
Positive Answer ◽  
Biogenic Elements ◽  
Habitable Zones ◽  
The Face ◽  
The Origin Of Life ◽  
Early Mars ◽  
Favorable Conditions ◽  
Open Question ◽  
Rocky Planets ◽  
Impact Erosion

AbstractThe clear evidence of water erosion on the surface of Mars suggests an early climate much more clement than the present one. Using a model for the origin of inner planet atmospheres by icy planetesimal impact, it is possible to reconstruct the original volatile inventory on Mars, starting from the thin atmosphere we observe today. Evidence for cometary impact can be found in the present abundances and isotope ratios of gases in the atmosphere and in SNC meteorites. If we invoke impact erosion to account for the present excess of129Xe, we predict an early inventory equivalent to at least 7.5 bars of CO2. This reservoir of volatiles is adequate to produce a substantial greenhouse effect, provided there is some small addition of SO2(volcanoes) or reduced gases (cometary impact). Thus it seems likely that conditions on early Mars were suitable for the origin of life – biogenic elements and liquid water were present at favorable conditions of pressure and temperature. Whether life began on Mars remains an open question, receiving hints of a positive answer from recent work on one of the Martian meteorites. The implications for habitable zones around other stars include the need to have rocky planets with sufficient mass to preserve atmospheres in the face of intensive early bombardment.

The dual nature of obesity in metabolic programming: quantity versus quality of adipose tissue

2020 ◽  
Vol 134 (18) ◽  
pp. 2447-2451
Author(s):  
Anissa Viveiros ◽  
Gavin Y. Oudit
Keyword(s):  
Adipose Tissue ◽  
Environmental Factors ◽  
Maternal Obesity ◽  
Metabolic Programming ◽  
Dual Nature ◽  
Prevalence Of Obesity ◽  
Adipose Tissue Volume ◽  
Males And Females ◽  
Metabolically Healthy

Abstract The global prevalence of obesity has been rising at an alarming rate, accompanied by an increase in both childhood and maternal obesity. The concept of metabolic programming is highly topical, and in this context, describes a predisposition of offspring of obese mothers to the development of obesity independent of environmental factors. Research published in this issue of Clinical Science conducted by Litzenburger and colleagues (Clin. Sci. (Lond.) (2020) 134, 921–939) have identified sex-dependent differences in metabolic programming and identify putative signaling pathways involved in the differential phenotype of adipose tissue between males and females. Delineating the distinction between metabolically healthy and unhealthy obesity is a topic of emerging interest, and the precise nature of adipocytes are key to pathogenesis, independent of adipose tissue volume.

Sign in / Sign up

Export Citation Format

Share Document