scholarly journals Acute Effects of Ammoniac Nitrogen on Marine Copepod Acartia pacifica When Exposed to Different Temperature Conditions

2018 ◽  
Vol 6 (2) ◽  
pp. 6
Author(s):  
Jiagen Shang ◽  
Qi Yu ◽  
Mengxue Lu
Keyword(s):  
Acute Toxicity ◽  
Temperature Gradients ◽  
Acute Effects ◽  
Marine Copepod ◽  
Temperature Conditions ◽  
Different Temperatures ◽  
Observation Results ◽  
Changing Tendency

Acute toxicity of ammoniac nitrogen on marine copepod Acartia pacifica when exposed to different temperatures of 10℃~25℃were performed under controlled lab conditions. The changing tendency of mortality was evaluated and the 48h LC50 was determined according to the observation. Results showed that the 48h LC50 in different temperature gradients were for Pacific spindle daphnia 48 h - LC50 is 65.889 mg/L for 25 ℃, 134.214 mg/L for 20 ℃, 71.247 mg/L for 15 ℃ and 27.318 mg/L for 10 ℃, respectively. Temperature seemed to exert impacts on the stress induced by ammoniac nitrogen, and the peak of 48h LC50 appeared in between 15 ℃ and 20 ℃. The toxicity of ammonia showed a tendency to decrease with the increase of temperature before the peak while the was significantly enhanced with temperature increasing thereafter. 

scholarly journals Conidia sporulation of Pyricularia oryzae in segments of wheat plants under six different temperatures

2020 ◽  
Vol 50 (4) ◽  
Author(s):  
Marcos Kovaleski ◽  
João Leodato Nunes Maciel ◽  
Gustavo Bilibio dos Santos ◽  
Alieze Nascimento da Silva ◽  
Carolina Cardoso Deuner
Keyword(s):  
High Temperature ◽  
Petri Dish ◽  
Pyricularia Oryzae ◽  
Causal Agent ◽  
Temperature Conditions ◽  
Wheat Blast ◽  
Conidia Production ◽  
Different Temperatures

ABSTRACT: Wheat blast is known for developing itself more intensely under relatively high temperature conditions but many aspects related to its epidemiology remain unknown. The objective of this research was to evaluate the sporulative capacity of Pyricularia oryzae Triticum (Pot), the causal agent of wheat blast, in tissues of wheat plants under different temperatures degrees. Wheat plants of the cultivar Anahuac 75, susceptible to blast, were inoculated in the stage of flowering with conidial suspensions (105 conidia/mL) of the Pot isolates Py 12.1.209 and Py 12.1.132. Seven days after the inoculation, plants were cut in the following segments: leaves, stems and rachis (with blast severity ranging from 40 to 60%). Groups of each one of the three plant segments with the lesions were disposed in Petri-dish moist chambers, that were submitted to six different temperature treatments (18, 21, 24, 27, 30 and 33 °C). The most appropriate model that related the conidia production with temperature was identified in the evaluations conducted with stems. The established equations allowed identifying that the highest production of conidia of Pot occurs between 24 and 27 °C.

Bi-Layered Model of Interfacial Thermal Stresses with the Effect of Different Temperatures in the Layers

2011 ◽  
Vol 87 ◽  
pp. 63-70 ◽  
Author(s):  
Sujan Debnath ◽  
Muhammad Ekhlasur Rahman ◽  
Woldemichael Dereje Engida ◽  
M. V. V. Murthy ◽  
K.N. Seetharamu
Keyword(s):  
Thermal Stresses ◽  
Physical Design ◽  
Temperature Gradients ◽  
Interfacial Stress ◽  
Stress Model ◽  
Interfacial Stresses ◽  
Linear Temperature ◽  
Layered Model ◽  
Die Attach ◽  
Different Temperatures

An interfacial shearing and peeling stress model is proposed to account for different uniform temperatures and thickness wise linear temperature gradients in the layers. This upgraded model can be viewed as a more generic form to determine interfacial stresses under different temperature conditions in a bi-layered assembly. The selected shearing and peeling stress results are presented for the case of die and die attach as commonly seen in electronic packaging. The obtained results can be useful in interfacial stress evaluations and physical design of bi-material assemblies, which are used in microelectronics and photonic applications.

Electric charge transfer associated with temperature gradients in ice

1961 ◽  
Vol 260 (1303) ◽  
pp. 523-536 ◽  
Keyword(s):  
Charge Transfer ◽  
Electric Charge ◽  
Contact Time ◽  
Temperature Gradients ◽  
Potential Difference ◽  
Contact Period ◽  
Maximum Charge ◽  
Different Temperatures ◽  
Electric Potentials ◽  
Set Up

The development of electric potentials in ice crystals under the influence of temperature gradients is investigated both theoretically and experimentally. The maintenance of a steady temperature gradient across a piece of ice is accompanied by concentration gradients of H + and OH - ions; because of the much greater mobility of H + ions, these diffuse more rapidly into the colder part of the ice and, in the steady state, a potential difference is set up across the ice crystal, the colder end being positive. A theory of this effect predicts a surface density of charge on the ends of the ice of σ = 5 x 10 -5 (d T /d x ) e. s. u. cm -2 and a potential difference across a uniform specimen of about 2Δ T mV, where Δ T is the temperature difference across the ends. These values are quite well confirmed by a series of experiments on specimens of highly purified ice. When two pieces of ice of initially different temperatures are brought into temporary contact and separated, the warmer acquires a negative charge and the colder an equal positive charge. The theory indicates that a maximum charge transfer of 3 x 10 -3 Δ T , e. s. u. cm -2 should occur with a contact time of about 0.01 s and that it should thereafter decline as the two pieces of ice become more nearly equal in temperature. The theoretical value for the charge developed for a contact time of ~ 0.01 s is well confirmed by experiments which also show that very little charge separation occurs if the contact period exceeds ½ s. Experiments in which the ice was contaminated with carbon dioxide, hydrofluoric acid, and sodium chloride in concentrations of up to 50 times that normally present in rain water, showed that the electrification was not greatly influenced by these impurities. These phenomena are thought to be of basic importance in the generation of electric charge in thunderstorms, this aspect being developed in the following paper.

Acute Toxicity of Arsenic under Different Temperatures and Salinity Conditions on the White Shrimp Litopenaeus vannamei

2013 ◽  
Vol 152 (3) ◽  
pp. 350-357 ◽  
Author(s):  
Jesús Alberto Valentino-Álvarez ◽  
Gabriel Núñez-Nogueira ◽  
Laura Fernández-Bringas
Keyword(s):  
Acute Toxicity ◽  
Litopenaeus Vannamei ◽  
White Shrimp ◽  
Different Temperatures

Preschoolers’ Time On-Task and Physical Activity During a Classroom Activity Break

2015 ◽  
Vol 27 (1) ◽  
pp. 160-167 ◽  
Author(s):  
E. Kipling Webster ◽  
Danielle D. Wadsworth ◽  
Leah E. Robinson
Keyword(s):  
Physical Activity ◽  
Vigorous Physical Activity ◽  
Preschool Age ◽  
Time On Task ◽  
Acute Effects ◽  
Task Behavior ◽  
Short Bout ◽  
School Day ◽  
On Task Behavior ◽  
Observation Results

This study examined the acute effects of a 10-min teacher-implemented classroom-based activity break (AB) on physical activity participation and time on-task in a preschool-age population. 118 (M age = 3.80 ± 0.69 years) students from one preschool served as participants. The intervention took place over 4 days: 2 days AB were conducted and 2 days typical instruction occurred. Physical activity was monitored via accelerometry and time on-task was measured by direct observation. Results demonstrated that AB led to a higher percent of moderate-to-vigorous physical activity (MVPA) during the AB (M = 29.7%, p > .001). Breaks also promoted more on-task behavior (FU17 = 18.86, p > .001) following the AB. Specifically, the most off-task students before the break improved on-task behavior by 30 percentage points (p > .001). Percent of school day MVPA was also higher during AB days (i117 = 3.274, p = .001). Findings indicate teachers may improve time on-task postbreak for preschoolers with a short bout of physical activity in the classroom, especially in children who are the most off-task. In addition, classroom-based AB resulted in marginal increases in MVPA during breaks that influenced whole day activity.

scholarly journals An experimental study of PMMA precision cryogenic micro-milling

2021 ◽  
Vol 1 (1) ◽  
pp. 15-21
Author(s):  
Ying Yan ◽  
Yujia Sun ◽  
Bo Li ◽  
Ping Zhou
Keyword(s):  
Processing Parameters ◽  
Polymer Materials ◽  
Micro Milling ◽  
Dominant Factor ◽  
Processing Temperature ◽  
Shape Accuracy ◽  
Optical Components ◽  
Temperature Conditions ◽  
Different Temperatures ◽  
Cryogenic Method

Polymethyl methacrylate (PMMA) has been used more and more widely in the fields of microfluidic devices and high-precision optical components due to its excellent mechanical and optical properties. Micro-milling is one of the methods that has been used in the machining of polymer materials. The machinability of PMMA is highly dependent on temperature, and the cryogenic method is also applied to control the processing temperature. In this work, the PMMA was milled with different processing parameters at the temperature of -55℃ and 25℃. The influence of each milling parameter on the surface quality under different temperature conditions were investigated. According to the results, the cutting depth is the dominant factor that influenced the surface roughness. The shape accuracy of the rectangular microgroove processed under low-temperature conditions is better. The material removal mechanism under different temperatures was also discussed, and the material is cut in a brittle way under low temperatures.

scholarly journals Effects of Fe3+ on Acute Toxicity and Regeneration of Planarian (Dugesia japonica) at Different Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Xue Ding ◽  
Linxia Song ◽  
Yahong Han ◽  
Yingbo Wang ◽  
Xiaowang Tang ◽  
...  
Keyword(s):  
Water Pollution ◽  
Acute Toxicity ◽  
Toxic Effects ◽  
Regeneration Rate ◽  
Planarian Regeneration ◽  
Suitable Temperature ◽  
Different Temperatures ◽  
Dugesia Japonica ◽  
The Difference ◽  
Head Regeneration

Objective. To investigate the effects of different concentrations of Fe3+ on the acute toxicity and regeneration of planarian at different temperatures. Method. The planarians were treated with 40 mg/l, 50 mg/l, 60 mg/l, and 70 mg/l Fe3+ solution and placed in 15°C, 20°C, and 25°C, respectively, to observe the mortality and the poisoning pattern of the planarian. In addition, the planarians were cut into three parts of head, trunk, and tail, then placed in Fe3+ solution at concentrations of 10 mg/l, 15 mg/l, 20 mg/l, and 30 mg/l, and placed in 15°C, 20°C, and 25°C respectively, and the regeneration rate of the planarian was investigated. Results. At the same temperature, in the concentration of Fe3+ from 40 mg/l to 70 mg/l, the mortality of the planarian increased with the increasing of the concentration of Fe3+; at the same concentration and different temperatures, the death speed of the planarian is the fastest at 20°C, the next at 25°C, and the lowest at 15°C, indicating that the toxic effect of Fe3+ can be accelerated at a suitable temperature of 20°C. At the same temperature, in the low concentration of Fe3+ from 10 mg/l to 30 mg/l, the regeneration rate of the planarian gradually decreased with the increasing of the concentration of Fe3+; at the same concentration and different temperature, the regeneration rate of planarian was faster at 20°C and 25°C, but the difference between 20°C and 25°C was small, and the slowest at 15°C, indicating that the low temperature significantly affects the planarian regeneration speed. The study also found the regeneration rates of the head, trunk, and tail of the planarian were different; the head regeneration was the fastest, the trunk was the second, and the tail was the slowest. Conclusion. Fe3+ had obvious toxic effects on the survival and regeneration of planarian; the planarian is sensitive to Fe3+ and may be used to detect Fe3+ water pollution; in addition, temperature can affect the toxic effects of Fe3+ and thus affect the survival and regeneration of the planarian. Therefore, the temperature should be taken into consideration when detecting water Fe3+ pollution.

Acute toxicity of ammonia in Meagre (Argyrosomus regiusAsso, 1801) at different temperatures

2015 ◽  
Vol 47 (11) ◽  
pp. 3593-3598 ◽  
Author(s):  
Mehmet Kir ◽  
Mustafa Topuz ◽  
Murat Can Sunar ◽  
Havva Topuz
Keyword(s):  
Acute Toxicity ◽  
Different Temperatures
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