scholarly journals Investigating factors that set the lower elevational limit of Canada jays (Perisoreus canadensis) on Vancouver Island

2021 ◽  
Author(s):  
Nathaniel Quarrell ◽  
Dan Strickland ◽  
D Ryan Norris
Keyword(s):  
Abiotic Factors ◽  
Antimicrobial Properties ◽  
Vancouver Island ◽  
High Elevation ◽  
Effect Of Temperature ◽  
Late Winter ◽  
Definitive Evidence ◽  
Subalpine Zone ◽  
Perisoreus Canadensis ◽  
Better Than

The biotic and abiotic factors responsible for determining ranges of most species are poorly understood. The Canada jay (Perisoreus canadensis Linnaeus, 1766) relies on perishable cached food for over-winter survival and late-winter breeding and the persistence of cached food could be a driver of range limits. We confirmed that the Canada jay’s lower elevational limit on Vancouver Island, British Columbia, matches that of the subalpine zone (900 m) and then conducted simulated caching experiments to examine the influence of antimicrobial properties of subalpine tree species (biotic) and of temperature (abiotic) on the preservation of cached food. We found that two high-elevation species, Yellow cedar (Callitropsis nootkatensis D. Don, D.P. Little) and Amabilis fir (Abies amabilis Douglas ex J. Forbes) preserved cached blueberries and chicken flesh better than other trees but they also occurred well below the lower limit of Canada jays. The effect of temperature was similarly unclear; while food cached at 1150 m retained 17 % more mass than food cached at 550 m, there was no difference in percent mass remaining of food placed 70 m above, versus 120 m below, the Jay lower elevational limit. Thus we were unable to provide definitive evidence that either of the proposed abiotic or biotic factors was responsible for setting the Canada jay lower elevational limit of resident Canada jays.

scholarly journals Composition and Antimicrobial Properties of Essential Oils of Laser Trilobum Rhizomes and Fruits

2017 ◽  
Vol 12 (3) ◽  
pp. 1934578X1701200
Author(s):  
Milica Drobac ◽  
Silvana Petrović ◽  
Marina Milenković ◽  
Maria Couladis ◽  
Jelena Kukić-Marković ◽  
...  
Keyword(s):  
Essential Oils ◽  
Antimicrobial Properties ◽  
Antimicrobial Effect ◽  
Reference Compound ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Fruit Oil ◽  
Total Oil ◽  
Dark Blue ◽  
Better Than

The compositions of hydrodistillated essential oils of Laser trilobum (L.) Borkh. rhizomes and fruits from Serbia, were investigated using GC and GC/MS. In the dark-blue rhizome oil forty-six compounds (93.1% of the total oil) were identified, with α-pinene (31.5%), γ-terpinene (9.0%), p-cymene (7.9%), β-pinene (6.1%) and 1,4-dimethylazulene (6.0%) as the major components. In the colorless fruits oil, twenty components (96.8% of the total oil) were identified, and the main constituents were limonene (51.6%) and perillaldehyde (26.8%). The antimicrobial activity of the oils was tested using the broth microdilution method against nine bacterial and two fungal strains. The oils revealed significant antimicrobial effect, mainly better than that of thymol, used as a reference compound. The strongest activity was recorded for the rhizome oil against Escherichia coli, Klebsiella pneumoniae and Candida albicans (MICs=25 μg/mL), and the fruit oil against C. albicans ATCC 10259 (MIC=12.5 μg/mL).

scholarly journals Comparison of antimicrobial properties of two spices commonly consumed in Nigeria and effect of temperature on their antioxidant properties

2018 ◽  
Vol 17 (52) ◽  
pp. 1473-1483
Author(s):  
Chika C. Ogueke ◽  
Ehijie Augusta Azeke ◽  
Clifford I. Owuamanam ◽  
Moses Ojukwu ◽  
I. M. Agunwah ◽  
...  
Keyword(s):  
Antioxidant Properties ◽  
Antimicrobial Properties ◽  
Effect Of Temperature

scholarly journals Effect of temperature and mating pair on tribological properties of DLC and GLC coatings under high pressure lubricated by MoDTC and ZDDP

Friction ◽  
2020 ◽  
Author(s):  
Kang Liu ◽  
Jia-jie Kang ◽  
Guang-an Zhang ◽  
Zhi-bin Lu ◽  
Wen Yue
Keyword(s):  
Tribological Properties ◽  
Friction And Wear ◽  
Effect Of Temperature ◽  
Wear Properties ◽  
Dlc Coatings ◽  
Base Oil ◽  
Two Temperatures ◽  
Friction And Wear Properties ◽  
Lubrication Conditions ◽  
Better Than

AbstractDiamond-like carbon (DLC) and graphite-like carbon (GLC) coatings have good prospects for improving the surface properties of engine parts. However, further understanding is needed on the effect of working conditions on tribological behaviors. In this study, GLC and two types of DLC coatings were deposited on GCr15 substrate for investigation. The friction and wear properties of self-mated and steel-mated pairs were evaluated. Two temperatures (25 and 90 °C), three lubrication conditions (base oil, molybdenum dithiocarbamate (MoDTC)-containing oil, MoDTC+zinc dialkyldithiophosphate (ZDDP)-containing oil), and high Hertz contact stress (2.41 GPa) were applied in the experiments. The results showed that high temperature promoted the effect of ZDDP on steel-mated pairs, but increased wear under base oil lubrication. The increased wear for steel-mated pairs lubricated by MoDTC-containing oil was due to abrasive wear probably caused by MoO3 and β-FeMoO4. It was also found that in most cases, the tribological properties of self-mated pairs were better than those of steel-mated pairs.

scholarly journals Aridity weakens population-level effects of multiple species interactions on Hibiscus meyeri

2017 ◽  
Vol 115 (3) ◽  
pp. 543-548 ◽  
Author(s):  
Allison M. Louthan ◽  
Robert M. Pringle ◽  
Jacob R. Goheen ◽  
Todd M. Palmer ◽  
William F. Morris ◽  
...  
Keyword(s):  
Population Growth ◽  
Species Interactions ◽  
Abiotic Factors ◽  
Population Level ◽  
Distinct Species ◽  
High Elevation ◽  
Relative Strength ◽  
Herbaceous Plant ◽  
Species Abundances ◽  
Multiple Species

Predicting how species’ abundances and ranges will shift in response to climate change requires a mechanistic understanding of how multiple factors interact to limit population growth. Both abiotic stress and species interactions can limit populations and potentially set range boundaries, but we have a poor understanding of when and where each is most critical. A commonly cited hypothesis, first proposed by Darwin, posits that abiotic factors (e.g., temperature, precipitation) are stronger determinants of range boundaries in apparently abiotically stressful areas (“stress” indicates abiotic factors that reduce population growth), including desert, polar, or high-elevation environments, whereas species interactions (e.g., herbivory, competition) play a stronger role in apparently less stressful environments. We tested a core tenet of this hypothesis—that population growth rate is more strongly affected by species interactions in less stressful areas—using experimental manipulations of species interactions affecting a common herbaceous plant, Hibiscus meyeri (Malvaceae), across an aridity gradient in a semiarid African savanna. Population growth was more strongly affected by four distinct species interactions (competition with herbaceous and shrubby neighbors, herbivory, and pollination) in less stressful mesic areas than in more stressful arid sites. However, contrary to common assumptions, this effect did not arise because of greater density or diversity of interacting species in less stressful areas, but rather because aridity reduced sensitivity of population growth to these interactions. Our work supports classic predictions about the relative strength of factors regulating population growth across stress gradients, but suggests that this pattern results from a previously unappreciated mechanism that may apply to many species worldwide.

Study on Corrosion Resistance of Cr-Containing P110 Steel

2013 ◽  
Vol 740 ◽  
pp. 608-611 ◽  
Author(s):  
Ming Hua Liang ◽  
Zhi Yong Pan ◽  
Xiang Zhang
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Product ◽  
Corrosion Behavior ◽  
Local Corrosion ◽  
Effect Of Temperature ◽  
Corrosion Rates ◽  
P110 Steel ◽  
Better Than

The influence of Cr on corrosion behavior of P110 steel was studied in the simulated CO2 environment. The result demonstrated that the Cr cant change the effect of temperature on P110 steel. The corrosion rates of the two kinds of materials reached the peak at 90°C. The temperature has dual effects on corrosion, which caused the adhesive and productivity of corrosion product formed up 90°C are better than that formed below 90°C; The adding of Cr in the P110 steel can prohibit the local corrosion to occur.

scholarly journals The effect of temperature on tacticity for bulk thermal polymerization of styrene

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Farshid Ziaee ◽  
Mehdi Nekoomanesh ◽  
Hamid Salehi Mobarakeh ◽  
Hassan Arabi
Keyword(s):  
Thermal Polymerization ◽  
Effect Of Temperature ◽  
Polymerization Temperature ◽  
Deuterated Chloroform ◽  
Methylene Carbon ◽  
Aromatic Carbon ◽  
First Order ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Better Than

AbstractThree types of polystyrenes were prepared at different temperatures of 50, 150 and 250°C by bulk thermal polymerization of styrene below 20 percent of conversion. The assignment of all stereosequences at pentad level of quaternary aromatic carbon and hexad level of methylene carbon of the polystyrenes were done using 13C Liquid NMR in deuterated chloroform at similar conditions. Bernoullian and first-order Markov statistics were calculated and the results were compared with experimental NMR results. It is shown that first-order Markov statistics fit slightly better than Bernoullian statistics for the assigned carbons. The results indicated that by increasing polymerization temperature the probability of meso addition (Pm) in polystyrene chains was enhanced. Pm was calculated for polystyrenes prepared at 50, 150 and 250°C and corresponding values were 0.378, 0.398 and 0.402 respectively. It was shown that by increasing temperature the polymerization is directed toward the Bernoullian propagation. By increasing the NMR acquisition temperature from 20 to 65°C higher resolution especially in quaternary aromatic carbon was achieved and the related peak was splitted to 16 peaks corresponding to a heptad level compared to 10 peaks in 20°C.

Life History, Ecological Production, and an Empirical Mathematical Model of the Population of Sagitta elegans in St. Margaret's Bay, Nova Scotia

1971 ◽  
Vol 28 (7) ◽  
pp. 971-985 ◽  
Author(s):  
D. D. Sameoto
Keyword(s):  
Mathematical Model ◽  
Life History ◽  
Nova Scotia ◽  
Reproductive Potential ◽  
The Body ◽  
Effect Of Temperature ◽  
Late Winter ◽  
Turnover Rates ◽  
Flushing Rate ◽  
Effects Of Temperature

The population of Sagitta elegans Verrill in St. Margaret's Bay, Nova Scotia, was polymodal throughout the year. The modes were distinct enough to be considered as representing subpopulations. Four subpopulations were present in the Bay during the early winter and a fifth subpopulation entered the Bay during the late winter. The growth of the subpopulations was followed through the year and related to the mean water temperature. A mathematical model describing the effect of temperature on development, length of the life cycle, and reproductive potential is presented. The model simulates the effects of temperature on the body length at maturation, ovary length, generation time, and numbers surviving at various body lengths. Predictions are made on the changes in population size due to temperature, and mortality and flushing rate changes. The calorific content of the animals at different stages of the life history are given along with the carbon content of the animals. A yearly ecological production figure is given based on the turnover rates derived from the Allen curve for one of the subpopulations. The significance of the findings is discussed in relation to the geographic distribution of the species.

scholarly journals Biotic interactions are more important at species’ warm vs. cool range-edges: a synthesis

2021 ◽  
Author(s):  
Alexandra Paquette ◽  
Anna L. Hargreaves
Keyword(s):  
Abiotic Factors ◽  
Empirical Support ◽  
Ecological Factors ◽  
Biotic Interactions ◽  
High Elevation ◽  
Range Limits ◽  
Low Latitude ◽  
Comprehensive Literature Review ◽  
Mixed Support ◽  
Species Being

ABSTRACTPredicting which ecological factors constrain species distributions is a fundamental question in ecology and critical to forecasting geographic responses to global change. Darwin hypothesized that abiotic factors generally impose species’ high-latitude and high-elevation (typically cool) range limits, whereas biotic interactions more often impose species’ low-latitude/low-elevation (typically warm) limits, but empirical support has been mixed. Here, we clarify three predictions arising from Darwin’s hypothesis, and show that previously mixed support is partially due to researchers testing different predictions. Using a comprehensive literature review (886 range limits), we find that biotic interactions, including competition, predation, and parasitism, influenced species’ warm limits more often than species’ cool limits. At cool limits, abiotic factors were consistently more important than biotic interactions, but temperature contributed strongly to cool and warm limits. Our results suggest that most range limits will be sensitive to climate warming, but warm limit responses will depend strongly on biotic interactions. “When we travel southward and see a species decreasing in numbers, we may feel sure that the cause lies quite as much in other species being favored, as in this one being hurt. (Whereas)… the number of species, and therefore of competitors, deceases northwards; hence in going northward or in ascending a mountain, we far oftener meet with stunted forms, due to the directly injurious action of climate” –Darwin 1859

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