2,710 research outputs found
TOXICITY OF SOME INSECTICIDES COMMONLY USED FOR RICE INSECTS CONTROL TO PREDATORS OF RICE-HOPPERS
No full textDevelopment of an Upwinding Scheme through the Minimization of Modified Wavenumber Error for the Incompressible Navier-Stokes Equations
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Self-lubricating Ni-P-MoS2 composite coatings
Full text linkTribological coatings with low coefficients of friction are in high demand by various industries since they can improve machine efficiency and have an environmental impact. A self-lubricating Ni-P-MoS2 composite coating has been successfully deposited on a mild steel substrate by electrodeposition. The effects of MoS2 on the tribological coatings have been investigated. Compared to a pure Ni-P coating, the Ni-P-MoS2 composite coating exhibited a dramatic reduction in friction coefficient against a bearing steel ball from 0.45 to 0.05. Examination and analysis of the worn surfaces and wear debris, the composite coating showed minimum wear and oxidisation compared to the severe wear and oxidation observed in the pure Ni-P coating. The evolution of MoS2 particles in sliding wear has been elucidated
Natural Variation of the Circadian Clock in Neurospora
No full textMost living organisms on earth experience daily and expected changes from the rotation of the earth. For an organism, the ability to predict and prepare for incoming stresses or resources is a very important skill for survival. This cellular process of measuring daily time of the day is collectively called the circadian clock. Because of its fundamental role in survival in nature, there is a great interest in studying the natural variation of the circadian clock. However, characterizing the genetic and molecular mechanisms underlying natural variation of circadian clocks remains a challenging task. In this chapter, we will summarize the progress in studying natural variation of the circadian clock in the successful eukaryotic model Neurospora, which led to discovering many design principles of the molecular mechanisms of the eukaryotic circadian clock. Despite the success of the system in revealing the molecular mechanisms of the circadian clock, Neurospora has not been utilized to extensively study natural variation. We will review the challenges that hindered the natural variation studies in Neurospora, and how they were overcome. We will also review the advantages of Neurospora for natural variation studies. Since Neurospora is the model fungal species for circadian study, it represents over 5 million species of fungi on earth. These fungi play important roles in ecosystems on earth, and as such Neurospora could serve as an important model for understanding the ecological role of natural variation in fungal circadian clocks.Advances in Genetics, Vol. 99
FIG. 4. — Cantharellus yunnanensis W.F.Chiu, holotype S.C in New insights into the taxonomy of the genus Cantharellus in China: epityfication of C. yunnanensis W.F. Chiu and the first record of C. cibarius Fr.
No full textFIG. 4. — Cantharellus yunnanensis W.F.Chiu, holotype S.C. Shen (8090).Published as part of Shao, Shi-Cheng, Liu, Pei-Gui, Wei, Tie-Zheng & Herrera, Mariana, 2021, New insights into the taxonomy of the genus Cantharellus in China: epityfication of C. yunnanensis W.F. Chiu and the first record of C. cibarius Fr., pp. 25-37 in Cryptogamie, Mycologie 20 (3) on page 33, DOI: 10.5252/cryptogamie-mycologie2021v42a3, http://zenodo.org/record/781522
(7(3):1-6)EFFECTS OF SOME MINOR ELEMENTS ON THE NURSERY BED OF RICE PLANTS (II) Effects of Minor Elements on Rice Seedlings (Water Culture Experiment)
No full text為明瞭施用微量元素對稻苗生育之影響，於玻璃室舉行苗床水耕試驗。使用燒杯為水耕容器，上面蓋紗布裝滿培養液然後播種。
依適量之錳處理，稻苗生育良好比對照區（無錳）確實可得健全之稻苗。錳之適當濃度為Mn 2ppm，而超過20ppm就呈現毒害，1,000ppm則致枯死。於Mn 20ppm，稻葉開始向中葉脈捲縮生長受阻害，此毒害現象在50ppm以上時更厲害。錳濃度至200ppm，稻種發芽率無受影響，而超過500ppm就降低。
化學分耕結果，隨培養液錳濃度增加稽苗中錳濃度也增加有正相關，則葉部錳含量為trace~2.13%根部為trace~0.92%。受錳處理之稻苗氣含量增加而鉀含量也稍有增加之傾向，磷含量者無此傾向。
對硼、銅、鋅、鉬、鈷另進行簡單試驗，其適量之施用對稻苗生育影響良好。據稻苗中三要素分析之結果，銅及鈿高濃度處理區之磷含量及硼高濃度處理區之鉀含量均有減低。
Water culture experiments were carried out for the purpose of ascertaining the effect of minor elements on the growth of rice seedlings. Beakers were used as water culture vessels. After laid the gauze on beakers for the germination beds, rice seeds were planted on them.
Rice seedlings in the treated plot, which the proper amounts of manganese were applied, grew better than the check plot. The optimum Mn concentration in culture solution for rice seedlings was 2 ppm. The treatment of Mn 20 ppm retard the growth of the plants and at Mn 1000 ppm all the seedlings were killed. It would be seen that even at Mn 20 ppm treatment the leaves rolled in towards the mid-rib and decreased the growth. This toxic symptom and decrease were particularly marked when the concentration of Mn rised from 20 to 50 ppm. The germination percentage of rice seeds was affected at the level of Mn 500 ppm but not at below 200 ppm.
Chemical analysis for N, P2O5, K2O and Mn showed that Mn contents in seedlings were increased in proportion to the concentration of Mn in culture solution. The result obtained was Mn trace-2.13% in leaves and Mn trace-0.92% in roots. The Mn treatment greatly increased the uptake of nitrogen and slightly increased potassium but not phosphorous.
The simple trials for B, Cu, Zn, Mo, Co on rice seedlings were also conducted. Better growth of the seedlings were obtained at the optimum treatments of these minor elements. The treatment of higher concentration of copper and molybdenum seemed to depress the uptake of phosphorous, so did boron to the uptake of potassium
(6(4):41-57)A FIELD SURVEY OF THE POPULATION DENSITY OF THE PINEAPPLE MEALYBTJG AND RED-MITE IN FORMOSA (Taiwan)
No full text鳳梨粉介殼蟲(Dysmicoccus brevipis CKll.)及鳳梨赤蝨(Stigmaeus flouridanus Banks)為鳳梨之主要害蟲，蔓延廣泛，為害甚烈，頗為一般人所重視，蓋因鳳梨粉介殼蟲能傳播毒素，引起鳳梨急性萎凋病之發生，而鳳梨赤蝨與急性萎凋病之關係，雖尚無定論，然因其寄生，而致生長不良，似可斷言。筆者等為明瞭其分佈情形及發生實況，藉為防治之根據，特作一較為精密而廣泛之實地調查，自41年4月24日至5月29日，歷時一月有餘。茲將調查所得，報告於後，以供同道者之參考。
As in other parts of the world, the mealybug (Dysmicoccus brevies Ckll.) and red-mite (Stigmaeus floidanus Banks) constitute the commonest and most important pests of pineapple in Formosa. In April 24 to May 29, 1952, inclusive, an intensive field survey of these two pests was made at 11 cultivating centers in southern and central parts of this island. Totally 28 plots (517 plants) representing different environmental conditions were sampled at random and immediately following this, the actual number of mealybug adults and nymphs on different parts of the plants were counted. The population density of the red-mite, however, was figured out by measuring the area infested and only five outer most leaves of each plant were examined.
The result of this survey revealed that 57.64% of the plants were infested by mealybugs and each plant harboured, in average, 35.71 such insects. Of 18.462 mealybugs thus sampled, 34.50% were found on leaf-bases, 32.59% on root system, 14.04% on fruits, 8.35% on fruit-pedicels and 8.18% on slip. In general, the population density was significantly lower where the seedlings have been fumigated prior to transplantation, and where the slope of the pineapple field was facing west (rather than facing south).
In the case of the red-mite, 80.41% of the plants were found to be infested and the infested area on each plant is 316 sq. mm. in average. Its population density seems, on the other hand, more or less correlated with soil humidity
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