Decrease of CO2 exchange in Scots pine after naturally occurring or artificial low temperatures

1977 ◽  
Vol 7 (3) ◽  
pp. 462-468 ◽  
Author(s):  
Paavo Pelkonen ◽  
Pertti Hari ◽  
Olavi Luukkanen
Keyword(s):  
Low Temperatures ◽  
Laboratory Experiments ◽  
Co2 Exchange ◽  
Additional Parameter ◽  
Naturally Occurring ◽  
Pine Seedlings ◽  
Measuring Period ◽  
Infrared Gas Analyzer ◽  
Better Than ◽  
Modelling Approach

A decrease in the net photosynthetic rate was recorded using an infrared gas analyzer after subjecting pine seedlings to naturally occurring or artificial low temperature pulses in field and laboratory experiments. Mathematical models were developed to quantify the depression in CO2 exchange observed when autumn measurements taken in the field were analyzed. A model which included a mathematically determined additional parameter gave values more closely correlated with CO2 exchange at the end of the measuring period better than one which included only temperature and light as independent variables. This modelling approach was similar to one used earlier to quantify the effect of water stress on photosynthesis. The same kind of effect was found in a laboratory experiment after artificial low temperatures, as shown in this paper.

scholarly journals Evaluation of Physical Barriers to Protect Ponderosa Pine Seedlings from Pocket Gophers

1999 ◽  
Vol 14 (3) ◽  
pp. 164-168 ◽  
Author(s):  
Michael J. Pipas ◽  
Gary W. Witmer
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Seedling Mortality ◽  
Pocket Gophers ◽  
Thomomys Talpoides ◽  
Pine Seedlings ◽  
Physical Barriers ◽  
Growth Of Seedlings ◽  
Medium Weight ◽  
Better Than

Abstract A 2 yr study on the Rogue River and Mt. Hood National Forests in Oregon evaluated physical barriers for protection of Pinus ponderosa seedlings against damage by Thomomys talpoides. Seedlings protected with one of three weights of: (1) plastic mesh tubing (Vexar®) or (2) sandpapertubing (Durite®) were evaluated against control seedlings. On the Rogue River sites, Vexar® seedlings had the highest survival (62.6%), followed by the controls (59.1%), then Durite® seedlings (17.9%). Gophers were the primary cause of death for the Vexar® seedlings, versus desiccation for the Durite® seedlings. On the Mt. Hood sites, heavyweight Vexar® seedlings had the highest survival (35.4%), medium-weight Durite® seedlings the lowest (2.7%). Seedling mortality caused by gophers was highest for controls (70.2%), followed by light-weight (62.2%) and heavy-weight (53.9%) Vexar® treatments. Overall survival was low (Rogue River = 42%, Mt. Hood = 19.8%). Growth was greatest for the control seedlings but only significantly greater than growth of Durite® seedlings on the Rogue River sites. Growth of seedlings was not compromised by the Vexar® tubing. Although neither type of tubing was highly protective, Vexar® tubes performed better than Durite® tubes. West. J. Appl. For. 14(3):164-168.

Instrumental Distortions of Raman Lines

1982 ◽  
Vol 36 (4) ◽  
pp. 424-427 ◽  
Author(s):  
A. K. Arora ◽  
V. Umadevi
Keyword(s):  
Low Temperatures ◽  
Full Width ◽  
Line Shapes ◽  
Peak Intensity ◽  
Empirical Relations ◽  
Extended Range ◽  
Main Component ◽  
Lorentzian Spectrum ◽  
True Peak ◽  
Better Than

The effect of spectrometer resolution on the peak intensity and the full width at half maximum (FWHM) of a Lorentzian spectrum is obtained by evaluating the convoluted line shapes. Spectrometer resolution functions (SRF) having Gaussian and triangular profiles are considered separately. Empirical relations to estimate the true peak intensity and the FWHM from the observed parameters are suggested. These relations are valid over an extended range of parameters with an accuracy better than that of other methods suggested earlier. As an application, the true FWHM's and peak intensities of the main component of the Raman active Ag mode of sulphate ion in potash alum at low temperatures are evaluated.

Laboratory Experiments of Mass Transfer in the London Clay

1988 ◽  
Vol 127 ◽  
Author(s):  
P. J. Bourke ◽  
D. Gilling ◽  
N. L. Jefferies ◽  
D. A. Lever ◽  
T. R. Lineham
Keyword(s):  
Mass Transfer ◽  
Porous Media ◽  
Radioactive Waste ◽  
Mass Transport ◽  
Mathematical Models ◽  
Laboratory Experiments ◽  
Naturally Occurring ◽  
Diffusion And Convection ◽  
Waste Repository ◽  
London Clay

ABSTRACTAqueous phase mass transfer through the rocks surrounding a radioactive waste repository will take place by diffusion and convection. This paper presents a comprehensive set of measurements of the mass transfer characteristics for a single, naturally occurring, clay. These data have been compared with the results predicted by mathematical models of mass transport in porous media, in order to build confidence in these models.

scholarly journals Dehumidified Air-Assisted Spray-Drying of Cloudy Beetroot Juice at Low Temperature

2021 ◽  
Vol 11 (14) ◽  
pp. 6578
Author(s):  
Aleksandra Jedlińska ◽  
Alicja Barańska ◽  
Dorota Witrowa-Rajchert ◽  
Ewa Ostrowska-Ligęza ◽  
Katarzyna Samborska
Keyword(s):  
Particle Size ◽  
Physicochemical Properties ◽  
Spray Drying ◽  
Low Temperatures ◽  
Beetroot Juice ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Tapped Density ◽  
Lower Loss ◽  
Better Than

This paper discusses the physicochemical properties of powders obtained by spray drying of cloudy beetroot juice, using dehumidified air in variants with or without carriers. The inlet air temperature was 130 °C or 90 °C, and the addition of the carriers was at a ratio of juice to carrier solids of 3:2. In the obtained powders, the following physicochemical properties were determined: water content and water activity, apparent density, loose and tapped density, porosity, flowability, particle size and morphology, and the content and retention of betalains. It was possible to dry cloudy beetroot juice without the use of carriers at low temperatures (90 or 130 °C). The 100% beetroot powders were characterized by satisfactory physicochemical properties, often better than those with carriers (including lower hygroscopicity and higher color saturation and yield). A lower loss of betalains was found for the powders with the addition of carriers. The best process yields were obtained for the powder without carriers at 130 °C and 90 °C.

scholarly journals Uplift Resistance Capacity of Anchor Piles used in Marine Aquaculture

2021 ◽  
Author(s):  
Fukun Gui ◽  
Jianqiao Kong ◽  
Dejun Feng ◽  
Xiaoyu Qu ◽  
Fang Zhu ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Failure Load ◽  
Lateral Displacement ◽  
Single Pile ◽  
Initial Tension ◽  
Marine Aquaculture ◽  
Pile Diameter ◽  
Single Piles ◽  
Uplift Resistance ◽  
Better Than

Abstract Anchor piles are widely used in marine aquaculture, and their uplift resistance capacity largely determines their safety, especially in harsh ocean environments. However, a practical guide on its design and installation is wanting. Laboratory experiments were conducted to investigate the effect of the initial tension angle, pile diameter, embedded depth, and pile configuration on the uplift resistance capacity of anchor piles for marine aquaculture under oblique loads. The results show that increasing the initial tension angle of circular and square single piles can significantly improve the uplift resistance capacity. The failure load of the square single pile was slightly higher than that of the circular single pile. Increasing the pile diameter can effectively improve the failure load and delay the development speed of the pile top displacement. Increasing the embedded depth can effectively improve the failure load and increase the lateral displacement of the pile top. The uplift resistance capacity of the dual anchor piles was better than that of the single anchor piles. The layout configuration has little effect on the failure load, but has a large effect on the displacement development.

Theoretical Bioevaluation of 1,2,4-Thiadiazole-1,2,4-triazole Derivatives via Molecular Modelling Approach

2021 ◽  
Vol 6 (1) ◽  
pp. 40-46
Author(s):  
Oyebamiji Abel Kolawole ◽  
Akintelu Sunday Adewale ◽  
Simon N. Odoemene ◽  
Oyeneyin Oluwatoba Emmanuel ◽  
Semire Banjo
Keyword(s):  
Breast Cancer ◽  
Docking Study ◽  
Qsar Model ◽  
Qsar Study ◽  
Triazole Derivatives ◽  
Discovery Studio ◽  
Artificial Neural Network Ann ◽  
Type 3 ◽  
Better Than ◽  
Modelling Approach

Breast cancer still remains one of the precarious ailments among humans globally. The vulnerability of this ailment in homeopathic world remains colossal and this has drawn the attention of seasoned researchers to find lasting solution to this hazard. Therefore, 10 novel 1,2,4-thiadiazole-1,2,4-triazole derivatives were studied so as to explore their anti-breast cancer activities. The studied compounds were optimized using Spartan 14 and the QSAR study was executed by using Gretl and MATLAB. Also, docking study was observed using Pymol (for treating downloaded protein), Autodock Tool (for locating binding site in the downloaded protein and for converting ligand and receptor to .pdbqt format from .pdb format), Auto dock vina (for docking calculation) and discovery studio (for viewing the nonbonding interaction between the docked complexes). The selected descriptors were used to developed effective QSAR model and it was observed that the developed QSAR model using artificial neural network (ANN) predicted better than the prediction made by multiple linear regression (MLR). More so, the calculated binding affinity revealed that compound g (-11.4 kcal/mol) possess ability to inhibit 3α-hydroxysteroid dehydrogenase type 3 (PDB ID: 4xo6) than other studied compounds as well as etoposide (Standard).

scholarly journals Comparative Survival and the Cold-Induced Gene Expression of Pathogenic and Nonpathogenic Vibrio Parahaemolyticus from Tropical Eastern Oysters during Cold Storage

2020 ◽  
Vol 17 (6) ◽  
pp. 1836
Author(s):  
Francisco Alarcón Elvira ◽  
Violeta T. Pardío Sedas ◽  
David Martínez Herrera ◽  
Rodolfo Quintana Castro ◽  
Rosa María Oliart Ros ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Vibrio Parahaemolyticus ◽  
Cold Shock ◽  
Gene Expressions ◽  
Reverse Transcription Pcr ◽  
Naturally Occurring ◽  
Gene Response ◽  
Eastern Oysters ◽  
Kinetics Of

Expression of the regulatory stress rpoS gene controls the transcription of cspA genes, which are involved in survival and adaptation to low temperatures. The purpose of this study was to assess the growth kinetics of naturally occurring V. parahaemolyticus in shellstock oysters and in vitro and the cold-shock-induced expression of the rpoS and cspA gene response in vitro during postharvest refrigeration. Naturally contaminated eastern oysters (Crassostrea virginica) and pathogenic (Vp-tdh) and nonpathogenic (Vp-tlh) isolates were stored at 7 ± 1 °C for 168 h and 216 h, respectively. The regulatory stress (rpos) and cold-shock (cspA) gene expressions were determined by reverse transcription PCR. At 24 h, the (Vp-tdh) strain grew faster (p < 0.05) than the (Vp-tlh) strain in oysters (λ = 0.33, 0.39, respectively) and in vitro (λ = 0.89, 37.65, respectively), indicating a better adaptation to cold shock for the (Vp-tdh) strain in live oysters and in vitro. At 24 h, the (Vp-tdh) strain rpoS and cspA gene expressions were upregulated by 1.9 and 2.3-fold, respectively, but the (Vp-tlh) strain rpoS and cspA gene expressions were repressed and upregulated by −0.024 and 1.9-fold, respectively. The V. parahaemolyticus strains that were isolated from tropical oysters have adaptive expression changes to survive and grow at 7 °C, according to their virulence.

The effects of hatchery and wild ancestry and experience on the relative ability of steelhead trout fry (Oncorhynchus mykiss) to avoid a benthic predator

1995 ◽  
Vol 52 (11) ◽  
pp. 2476-2482 ◽  
Author(s):  
Barry A. Berejikian
Keyword(s):  
Oncorhynchus Mykiss ◽  
Predator Avoidance ◽  
Laboratory Experiments ◽  
Test Period ◽  
Natural Environments ◽  
Steelhead Trout ◽  
Visual Exposure ◽  
Natural Stream ◽  
Relative Ability ◽  
Better Than

Differences in selection regimes between hatchery and natural environments and environmental stimuli, among other factors, have the potential to cause differences in predator avoidance ability between hatchery and wild steelhead trout fry (Oncorhynchus mykiss). In two separate laboratory experiments, fry raised from eggs of wild Quinault River steelhead trout survived predation by prickly sculpin (Cottus asper) significantly better than size-matched offspring of a locally derived hatchery population, which were reared under similar conditions. Wild fry also survived predation better than hatchery fry in natural stream enclosures over a 3-day test period. Experience, in the form of 50-min visual exposure to sculpin predation on "sacrificial" steelhead trout, improved the ability of fry from both populations to avoid predation by sculpin. Wild-experienced fry were eaten in the fewest number of trials followed by wild-naive, hatchery-experienced, and hatchery-naive fry. The results of this study are consistent with the hypothesis that innate predator avoidance ability has been negatively altered through domestication and that attempts to condition hatchery-reared steelhead to avoid predators may be limited for domesticated populations.

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