12 resultados para Fire Frequency
em Brock University, Canada
Resumo:
The frequency and type of agonistic displays involved in male-male encounters should be significantly influenced by the presence of females. Discrete agonistic displays vary in energy expenditure and risk, and therefore should be dependent on available resources. The influence of live females and the scent of females, on the frequency of male agonistic displays was observed in a laboratory terrarium using the field cricket Gryllus bimaculatus. The effect of energy constraints on display frequency was also determined. Half the males were fed a diet high in protein and fet; the other males were fed a lower quality diet, for a 7-11 day period. The frequency of five individual displays and mating frequency were recorded using an Event Recorder and notebook. Each group of males was presented with three experimental conditions, over three days, involving the presence or absence of live females and female scent. The presence of females elicited an increase in all displays except antennation; female scent increased the frequency of antennations, mandible flares and grapples, but to a lesser extent than did live females. The frequency of grapples significantly increased for males fed the high quality diet; however diet did not influence the other displays. The combined influence of diet and condition was significant for mandible flare only. Mating frequency was not influenced by diet. However, the frequency ofthe displays were positively correlated with mating frequency for high quality fed males. Escalated displays involving high costs, such as grapple and mandible flare, increased in frequency when the benefits of winning contests were high in G.bimaculatus. Escalation to grapple behaviour was less evident for males fed the lower quality diet as this imposed energy constraints on high cost displays.
Resumo:
Fire blight is an economically important disease of apples and pears that is caused by the
bacterium Erwinia amylovora. Control of the disease depends on limiting primaly blosson1
infection in the spring, and rapidly removing infected tissue. The possibility of using phages to
control E.amylovora populations has been suggested, but previous studies have. failed to show
high treatment efficacies. This work describes the development of a phage-based biopesticide
that controls E. amylovora populations under field conditions, and significantly reduces the
incidence of fire blight.
This work reports the first use ofPantoea agglomerans, a non-pathogenic relative ofE.
amylovora, as a carrier for E. amylovora.phages. Its role is to support a replicating population of
these phages on blossom surfaces during the period when the flowers are most susceptible to
infection. Seven phages and one carrier isolate were selected for field trials from existing
collections of 56 E. amylovora phages and 249 epiphytic orchard bacteria. Selection of the .
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phages and carrier was based on characteristics relevant to the production and field perfonnance
of a biopesticide: host range, genetic diversity, growth under the conditions of large-scale
production, and the ability to prevent E. amylovora from infecting pear blossoms. In planta
assays showed that both the phages and the carrier make significant contributions to reducirig the
development of fire blight symptoms in pear blossoms.
Field-scale phage production and purification methods were developed based on the
growth characteristics of the phages and bacteria in liquid culture, and on the survival of phages
in various liquid media.
Six of twelve phage-carrier biopesticide treatments caused statistically signiflcant reductions in disease incidence during orchard trials. Multiplex real-time PCR was used to
simultaneously monitor the phage, carrier, and pathogen populations over the course of selected
treatments. In all cases. the observed population dynamics of the biocontrol agents and the
pathogen were consistent with the success or failure of each treatment to control disease
incidence. In treatments exhibiting a significantly reduced incidel1ce of fire blight, the average
blossom population ofE.amylovora had been reduced to pre-experiment epiphytic levels. In
successful treatments the phages grew on the P. agglomerans carrier for 2 to 3 d after treatment
application. The phages then grew preferentially on the pathogen, once it was introduced into this
blossom ecosystem. The efficacy of the successful phage-based treatnlents was statistically
similar to that of streptomycin, which is the most effective bactericide currently available for fire
blight prevention.
The in planta behaviour ofE. amylovora was compared to that ofErwinia pyrifoliae, a
closely related species that causes fire blight-like synlptoms on pears in southeast Asia. Duplex
real-time PCR was used to monitor the population dynamics of both species on single blossonls.
E. amylovora exhibited a greater competitive fitness on Bartlett pear blossoms than E. pyrifoliae.
The genome ofErwinia phage
Resumo:
Raman scattering in the region 20 to 100 cm -1 for fused quartz, "pyrex" boro-silicate glass, and soft soda-lime silicate glass was investigated. The Raman spectra for the fused quartz and the pyrex glass were obtained at room temperature using the 488 nm exciting line of a Coherent Radiation argon-ion laser at powers up to 550 mW. For the soft soda-lime glass the 514.5 nm exciting line at powers up to 660 mW was used because of a weak fluorescence which masked the Stokes Raman spectrum. In addition it is demonstrated that the low-frequency Raman coupling constant can be described by a model proposed by Martin and Brenig (MB). By fitting the predicted spectra based on the model with a Gaussian, Poisson, and Lorentzian forms of the correlation function, the structural correlation radius (SCR) was determined for each glass. It was found that to achieve the best possible fit· from each of the three correlation functions a value of the SCR between 0.80 and 0.90 nm was required for both quartz and pyrex glass but for the soft soda-lime silicate glass the required value of the SCR. was between 0.50 and 0.60 nm .. Our results support the claim of Malinovsky and Sokolov (1986) that the MB model based on a Poisson correlation function provides a universal fit to the experimental VH (vertical and horizontal polarizations) spectrum for any glass regardless of its chemical composition. The only deficiency of the MB model is its failure to fit the experimental depolarization spectra.
Resumo:
Sediment samples were taken from seven locations in the
WeIland River in December 1986 and April 1987. The DMSO extracts
of these sediment samples showed a significant (p
Resumo:
A. strain of Drosophila melanog-aster deficient in null amylase activity (Amylase ) was isolated from a wild null population of flies. The survivorship of Amylase homozygous flies is very low when the principal dietary carbohydrate source is starch. However, the survivorship of the null Amylase genotype is comparable to the wild type when the dietary starch is replaced by glucose. In addition, the null viability of the amylase-producing and Amylase strains is comparable v and very lm<] f on a medium with no carbohydrates . Furthermore, amylase-producing genotypes were shovm to excrete enzymatically active amylase protein into the food medium. The excreted amylase causes the external breakdown of dietary starch to sugar. These results led to the following null prediction: the viability of the A.mvlase genotype (fed on a starch rich diet) might increase in the presence of individuals which were amylase-producing. It was shown experimentally that such an increase in viability did in fact occur and that this increase v\Tas proportional to the number of mnylase..::producing fli.es present. These results provide a unique example of a non-"competi ti ve inter-genotype interaction, and one where the underlying physio~ logical and biochemical mechanism has been fully understood.
Resumo:
An advertisement addressed to the "celebration committees" for May 24th and July 1st. William Hand details his services for fireworks and other lighting. Price ranges are included and reviews/comments quoted from several newspapers.
Resumo:
A fire insurance policy in the amount of one thousand dollars through Aetna Insurance Company of Utica, New York. The cost of twenty two dollars and twenty five cents would give them a one year insurance policy from August 1851 through August 1852.
Resumo:
We assess the predictive ability of three VPIN metrics on the basis of two highly volatile market events of China, and examine the association between VPIN and toxic-induced volatility through conditional probability analysis and multiple regression. We examine the dynamic relationship on VPIN and high-frequency liquidity using Vector Auto-Regression models, Granger Causality tests, and impulse response analysis. Our results suggest that Bulk Volume VPIN has the best risk-warning effect among major VPIN metrics. VPIN has a positive association with market volatility induced by toxic information flow. Most importantly, we document a positive feedback effect between VPIN and high-frequency liquidity, where a negative liquidity shock boosts up VPIN, which, in turn, leads to further liquidity drain. Our study provides empirical evidence that reflects an intrinsic game between informed traders and market makers when facing toxic information in the high-frequency trading world.
Resumo:
This paper analyzes versions of the salvo model of missile combat where area fire is used by one or both sides in a battle. While these models share some properties with the area fire Lanchester model and the aimed fire salvo model, they also display some interesting differences, especially over the course of several salvos. Whereas the relative size of each force is important with aimed fire, with area fire it is the absolute size that matters. Similarly, while aimed fire exhibits square law behavior, area fire shows approximately linear behavior. When one side uses area and the other uses aimed fire, the model displays a mix of square and linear law behavior.
Resumo:
The Interlake Tissue Mills storage location was at the intersection of Glendale and Merritt Street in Merritton. In the 1850s, the Beaver Cotton Mills (later Merritton Cotton Mills) was built. It was a frame building that burned down in 1881. A sandstone structure replaced the previous building. In 1906, the cotton mill closed and in 1912, the Independent Rubber Company took over the building. The mill was doubled in size. The rubber company remained there for ten years and then the building remained vacant until 1935. Interlake Tissue Mills acquired the building for storage purposes. A fire razed the larger of the plant’s buildings on Memorial Day weekend in 1961. After the fire, Domtar used the smaller building for storage for a short time. This is currently the site of the Keg Restaurant.
Resumo:
Letter to Robert Nelles from the Office of the N.D. Mutual Fire Insurance Company regarding an assessment of 5% on the premium notes of this company. This is signed by Mr. Arnold, secretary of the N.D. Mutual F. Insurance Company, Dec. 15, 1849.
Resumo:
Insurance Policy from the Quebec Fire Assurance Company to Mr. Joseph Power Bradley for his household furniture, linen wearing apparels, glass, earthenware and printed books in a house occupied as a dwelling and belonging to Joseph Legare Junt in the town of Quebec, Oct. 10, 1830