scholarly journals Performance and competitiveness of red vs. green phenotypes of a cyanobacterium grown under artificial lake browning

ALGAE ◽  
2021 ◽  
Vol 36 (3) ◽  
pp. 195-206
Author(s):  
Kevin Erratt ◽  
Irena Creed ◽  
Camille Chemali ◽  
Alexandra Ferrara ◽  
Vera Tai ◽  
...  
Keyword(s):  
Photosynthetic Pigment ◽  
Niche Differentiation ◽  
Distinct Species ◽  
Environmental Drivers ◽  
Artificial Lake ◽  
Lake Algonquin ◽  
Chemical Effects ◽  
Physical And Chemical ◽  
The Impact ◽  
Provincial Park

Increasing inputs of dissolved organic matter (DOM) to northern lakes is resulting in ‘lake browning.’ Lake browning profoundly affects phytoplankton community composition by modifying two important environmental drivers—light and nutrients. The impact of increased DOM on native isolates of red and green-pigmented cyanobacteria identified as Pseudanabaena, which emerged from a Dolichospermum bloom (Dickson Lake, Algonquin Provincial Park, Ontario, Canada) in 2015, were examined under controlled laboratory conditions. The genomes were sequenced to identify phylogenetic relatedness and physiological similarities, and the physical and chemical effects of increased DOM on cellular performance and competitiveness were assessed. Our study findings were that the isolated red and green phenotypes are two distinct species belonging to the genus Pseudanabaena; that both isolates remained physiologically unaffected when grown independently under defined DOM regimes; and that neither red nor green phenotype achieved a competitive advantage when grown together under defined DOM regimes. While photosynthetic pigment diversity among phytoplankton offers niche-differentiation opportunities, the results of this study illustrate the coexistence of two distinct photosynthetic pigment phenotypes under increasing DOM conditions.

Modeling and Experimental Verification of SiC M-PVT Bulk Crystal Growth

2006 ◽  
Vol 527-529 ◽  
pp. 75-78 ◽  
Author(s):  
Peter J. Wellmann ◽  
Ralf Müller ◽  
Michel Pons
Keyword(s):  
Numerical Modeling ◽  
Chemical Nature ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Temperature Variations ◽  
Bulk Crystal Growth ◽  
Chemical Effects ◽  
Physical And Chemical ◽  
The Impact ◽  
Graphite Foam

We have studied the impact of the chemical nature of additional gases fed into the modified physical vapor transport (M-PVT) growth cell. In particular experiments were carried out using helium, argon, nitrogen and propane in the growth setup. Numerical modeling was used to address the underlying physical and chemical effects that impact the global temperature field. It is found that chemical decomposition of complex gases plays a secondary role as heat source or sink. However, temperature variations related to varying gas compositions fed to the systems are primarily induced by changes of the graphite foam isolation properties.

THE IMPACT OF PHYSICAL AND CHEMICAL WEATHERING ON IRON SLAG FROM STANDISH, NY

2019 ◽  
Author(s):  
Maria L. Leonard ◽  
◽  
Rachel M. Kelk ◽  
Dori J. Farthing
Keyword(s):  
Chemical Weathering ◽  
Iron Slag ◽  
Physical And Chemical ◽  
The Impact

scholarly journals Impacts of Environmental Factors on Head and Neck Cancer Pathogenesis and Progression

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 389
Author(s):  
Marisol Miranda-Galvis ◽  
Reid Loveless ◽  
Luiz Paulo Kowalski ◽  
Yong Teng
Keyword(s):  
Head And Neck Cancer ◽  
Environmental Factors ◽  
Head And Neck ◽  
Neck Cancer ◽  
Molecular Mechanisms ◽  
Metastatic Cancer ◽  
Environmental Drivers ◽  
Cancer Pathogenesis ◽  
Gene Environment ◽  
The Impact

Epidemiological and clinical studies over the past two decades have provided strong evidence that genetic elements interacting with environmental components can individually and collectively influence one’s susceptibility to cancer. In addition to tumorigenic properties, numerous environmental factors, such as nutrition, chemical carcinogens, and tobacco/alcohol consumption, possess pro-invasive and pro-metastatic cancer features. In contrast to traditional cancer treatment, modern therapeutics not only take into account an individual’s genetic makeup but also consider gene–environment interactions. The current review sharpens the focus by elaborating on the impact that environmental factors have on the pathogenesis and progression of head and neck cancer and the underlying molecular mechanisms involved. Recent advances, challenges, and future perspectives in this area of research are also discussed. Inhibiting key environmental drivers of tumor progression should yield survival benefits for patients at any stage of head and neck cancer.

scholarly journals Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner
Keyword(s):  
Hydraulic Conductivity ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Treated Wastewater ◽  
Soil Aggregate Stability ◽  
Irrigation Effects ◽  
Physical And Chemical ◽  
The Impact

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.

scholarly journals Templated quasicrystalline ordering of single elements and molecules

2014 ◽  
Vol 70 (a1) ◽  
pp. C81-C81
Author(s):  
H. R. Sharma ◽  
J. A. Smerdon ◽  
K. Nozawa ◽  
K. M. Young ◽  
T. P. Yadav ◽  
...  
Keyword(s):  
Substrate Surface ◽  
Chemical Properties ◽  
Scanning Tunneling ◽  
Three Dimension ◽  
Tunneling Microscopy ◽  
Quantum Size ◽  
Adsorption Energies ◽  
Molecular Layers ◽  
Physical And Chemical ◽  
The Impact

We have used quasicrystals as templates for the exploration of new epitaxial phenomena. Several interesting results have been observed in the growth on surfaces of the common Al-based quasicrystals [1]. These include pseudomorphic monolayers, quasiperiodically modulated multilayer structures, and fivefold-twinned islands with magic heights influenced by quantum size effects [1]. Here we present our recent works on the growth of various elements and molecules on a new substrate, icosahedral (i) Ag-In-Yb quasicrystal, which have resulted in various epitaxial phenomena not observed previously. The growth of Pb on the five-fold surface of i-Ag-In-Yb yields a film which possesses quasicrystalline ordering in three-dimension [2]. Using scanning tunneling microscopy (STM) and DFT calculations of adsorption energies, we find that lead atoms occupy the positions of atoms in the rhombic triacontahedral (RTH) cluster, the building block of the substrate, and thus grow in layers with different heights and adsorption energies. The adlayer–adlayer interaction is crucial for stabilizing the epitaxial quasicrystalline structure. We will also present the first example of quasicrystalline molecular layers. Pentacene adsorbs at tenfold-symmetric sites of Yb atoms around surface-bisected RTH clusters, yielding quasicrystalline order [3]. Similarly, C-60 growth on the five-fold surface of i-Al-Cu-Fe at elevated temperature produces quasicrystalline layer, where the growth is mediated by Fe atoms on the substrate surface [3]. The finding of quasicrystalline thin films of single elements and molecules opens an avenue for further investigation of the impact of the aperiodic atomic order over periodic order on the physical and chemical properties of materials.

Modeling to support physicochemical enhancement techniques

2021 ◽  
pp. 79-90
Author(s):  
Т. A. Pospelova
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Oil And Gas ◽  
Chemical Modeling ◽  
Comparative Structure ◽  
Water Cut ◽  
Physical And Chemical ◽  
Oil And Gas Companies ◽  
The Impact ◽  
Selection Of

The article discusses ways to increase the oil recovery factor in already developed fields, special attention is paid to the methods of enhanced oil recovery. The comparative structure of oil production in Russia in the medium term is given. The experience of oil and gas companies in the application of enhanced oil recovery in the fields is analyzed and the dynamics of the growth in the use of various enhanced oil recovery in Russia is estimated. With an increase in the number of operations in the fields, the requirements for the selection of candidates inevitably increase, therefore, the work focuses on hydrodynamic modeling of physical and chemical modeling, highlights the features and disadvantages of existing simulators. The main dependences for adequate modeling during polymer flooding are given. The calculation with different concentration of polymer solution is presented, which significantly affects the water cut and further reduction of operating costs for the preparation of the produced fluid. The possibility of creating a specialized hydrodynamic simulator for low-volume chemical enhanced oil recovery is considered, since mainly simulators are applicable for chemical waterflooding and the impact is on the formation as a whole.

scholarly journals The influence of field margins on the presence and spatial distribution of the European mole Talpa europaea L. within the agricultural landscape of northern Poland

2012 ◽  
Vol 64 (3) ◽  
pp. 971-980 ◽  
Author(s):  
Ewa Zurawska-Seta ◽  
T. Barczak
Keyword(s):  
Spatial Distribution ◽  
Agricultural Development ◽  
Agricultural Landscape ◽  
Field Margins ◽  
Talpa Europaea ◽  
Northern Poland ◽  
European Mole ◽  
Arable Fields ◽  
Physical And Chemical ◽  
The Impact

European moles are widespread in both cultivated and uncultivated areas in Poland. Their occurrence and distribution in relation to the physical and chemical characteristics of soil has been already studied in previous research. However, there is still an open question about the impact of the structure of anthropogenic habitats produced by agriculture on moles. The main aim of this study is to assess the influence of different kinds of field margins on the presence and spatial distribution of the European mole Talpa europaea L. in farmlands. Methods included the monitoring of six investigative sites in northern Poland. Observations were made during three six-month periods in 2005-2008 of the presence or absence of moles as recognized by recent molehills and surface tunnels. There was a very clear tendency by moles to occupy areas within arable fields close to field boundaries with wide verges containing ruderal and woodland communities with a spacious zone of ecotones. Narrow boundary strips were avoided by moles. In conclusion, the conducted research confirms that field margins have an impact on the presence and spatial distribution of moles within ploughed lands. Our results may be helpful in improving the relation between agricultural development and biodiversity conservation, and the rational use of nature by humankind.

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