Studies on the swarming Habits of Mosquitos and other Nematocera

1950 ◽  
Vol 41 (2) ◽  
pp. 227-258 ◽  
Author(s):  
Erik Tetens Nielsen ◽  
Hans Greve
Keyword(s):  
Light Intensity ◽  
Low Temperatures ◽  
Direct Relationship ◽  
Minor Importance ◽  
Atmospheric Humidity ◽  
Ancillary Studies ◽  
Swarming Behaviour

The principal object of this work was to elucidate the swarming behaviour of Aëdes cantans and other mosquitos, Chaoborus crystallinus and certain Chironomids. In addition, ancillary studies were made of the general ecology of these species. The swarms were found to consist entirely of males and to bear no direct relationship to mating or to the search for food. There was no noticeable difference between the swarming habits of the different species of mosquitos and even the differences between the Culicids and Chironomids were very slight. Swarming was observed to take place at about sunset in the evening and sunrise in the morning. The evening swarms appeared to be formed in response to decreasing light intensity and to disperse at a light intensity of about 7 Lux. Low temperatures may delay the start of swarming. The morning swarms started at about the same threshold of light intensity and at this time also their duration was reduced by low temperatures. Below about 50°F. they were not formed at all. Atmospheric humidity appeared to be of minor importance.

scholarly journals Nighttime Temperatures and Sunlight Intensities Interact to Influence Anthocyanin Biosynthesis and Photooxidative Sunburn in “Fuji” Apple

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaomin Xue ◽  
Ying Duan ◽  
Jinzheng Wang ◽  
Fengwang Ma ◽  
Pengmin Li
Keyword(s):  
Light Intensity ◽  
Low Temperatures ◽  
Anthocyanin Biosynthesis ◽  
High Light ◽  
Anthocyanin Accumulation ◽  
Low Light ◽  
Low Light Intensity ◽  
Apple Peel ◽  
Fuji Apple ◽  
Nighttime Temperatures

Light and low temperatures induce anthocyanin accumulation, but intense sunlight causes photooxidative sunburn. Nonetheless, there have been few studies of anthocyanin synthesis under different sunlight intensities and low nighttime temperatures. Here, low nighttime temperatures followed by low light intensity were associated with greater anthocyanin accumulation and the expression of anthocyanin biosynthesis genes in “Fuji” apple peel. UDP-glucose flavonoid-3-O-glucosyltransferase (UFGT) activity was positively associated with anthocyanin enrichment. Ascorbic acid can be used as an electron donor of APX to scavenge H2O2 in plants, which makes it play an important role in oxidative defense. Exogenous ascorbate altered the anthocyanin accumulation and reduced the occurrence of high light–induced photooxidative sunburn by removing hydrogen peroxide from the peel. Overall, low light intensity was beneficial for the accumulation of anthocyanin and did not cause photooxidative sunburn, whereas natural light had the opposite effect on the apple peel at low nighttime temperatures. This study provides an insight into the mechanisms by which low temperatures induce apple coloration and high light intensity causes photooxidative sunburn.

The Influence of Photoperiod and Temperature on the Induction of Diapause in Diataraxia Oleracea L. (Lepidoptera)

1950 ◽  
Vol 27 (3) ◽  
pp. 365-376
Author(s):  
M. J. WAY ◽  
B. A. HOPKINS
Keyword(s):  
Light Intensity ◽  
High Temperatures ◽  
Larval Stage ◽  
Low Temperatures ◽  
Food Plant ◽  
Larval Food ◽  
Controlled Substances ◽  
Larval Food Plant

The induction of diapause in the pupa of Diataraxia oleracea is influenced by temperature and photoperiod during the larval stage. Low temperatures and short photoperiods tend to induce diapause while high temperatures and long photoperiods tend to prevent diapause. Diapause is not influenced by light intensity during the larval stage providing the intensity is above a certain minimum. Diapause is prevented at high temperatures (30-34° C.) if the larvae are reared in darkness. The photoperiod is operative as a factor influencing diapause only between the beginning of the moulting sleep prior to ecdysis to the last instar and the 3rd-5th day of the last instar. A single diapause-preventing photo-period during the moulting sleep is probably sufficient to prevent diapause. Diapause in D. oleracea is not influenced by photoperiodically controlled substances in the larval food plant.

EAR LENGTH AND SPIKELET NUMBER OF WHEAT GROWN AT DIFFERENT TEMPERATURES AND LIGHT INTENSITIES

1965 ◽  
Vol 43 (3) ◽  
pp. 345-353 ◽  
Author(s):  
D. J. C. Friend
Keyword(s):  
Light Intensity ◽  
Low Temperatures ◽  
Dry Weight ◽  
High Light ◽  
Morphological Development ◽  
Spikelet Number ◽  
Light Intensities ◽  
Different Temperatures ◽  
Total Plant ◽  
Effects Of Temperature

The number of spikelets on the differentiating inflorescence and the ear at anthesis was highest at high light intensities and at low temperatures. The length of the developing inflorescence and the ear, the height of the main stem, and the total plant dry weight at the time of anthesis were also greatest under these conditions.These results are related to differential effects of temperature and light intensity on the rates and duration of apical elongation, morphological development of the ear, and spikelet formation.

Patterns of lichen photosynthesis and respiration following prolonged frozen storage

1978 ◽  
Vol 56 (17) ◽  
pp. 2119-2123 ◽  
Author(s):  
Douglas W. Larson
Keyword(s):  
Light Intensity ◽  
Low Temperatures ◽  
Physiological Activity ◽  
Frozen Storage ◽  
Experimental Systems ◽  
Long Term Storage ◽  
Photosynthesis And Respiration ◽  
Term Storage ◽  
Respiratory Responses

The effect of prolonged frozen storage on patterns of photosynthesis and respiration in the lichen Alectoria ochroleuca (Hoffm.) Massal. has been examined. The results indicate that this plant not only survives long-term exposure to low temperatures but also that its basic photosynthetic and respiratory responses to temperature, light intensity, and thallus moisture content are altered very little by long-term storage at −60 °C. This maintenance not only of absolute viability but also of the more subtle patterns of physiological activity suggests that such storage may be used to hold lichen material for use in multivariate experimental systems which require replicates having identical field pretreatment.

scholarly journals INVESTIGATION OF LIGHT INTENSITY OF LIGHT CURING UNITS AFTER DIFFERENT PERIODS OF USE

2021 ◽  
Vol 27 (4) ◽  
pp. 4164-4169
Author(s):  
Georgi Georgiev ◽  
◽  
Tsanka Dikova ◽  
Vladimir Panov ◽  
◽  
...  
Keyword(s):  
Light Intensity ◽  
20Th Century ◽  
Direct Relationship ◽  
Maximum Light ◽  
Quartz Tungsten Halogen ◽  
Halogen Light ◽  
Intensive Use ◽  
Operation Period ◽  
Light Curing

Quartz-tungsten halogen light curing units (LCUs) have been the main source of light for the polymerization of resin based composites (RBCs) for several decades. Since the beginning of the 20th century, however, their use has been reduced due to the invention and improvement of LED LCUs. Various factors can cause a decrease in the light intensity of LED LCUs, one of which is diode aging. The aim of the present paper is to study the change in light intensity of LCUs after different periods of intensive use. For this purpose, the light intensity of 94 regularly used LED LCUs aged between 1 and 10 years was measured with a digital radiometer. The devices were used in conventional mode with maximum light intensity. It was found that regardless of the type and model of LCU, there is a direct relationship between the time of use and light intensity - the longer the operation period of a device is and the more used it is, the lower its intensity is. The decrease in light intensity as devices age is different for different models, as well as for different devices of the same model. In the studied LCUs with a 10-year period of use, 77.5% have light intensity lower than the required minimum of 400 mW/cm2, which makes them unusable. It can be concluded that dentists should regularly monitor and measure the light intensity of their LCUs, especially as they age, to ensure the longevity of their restorative procedures.

THE SWARMING BEHAVIOUR OF CHIRONOMUS RIPARIUS (DIPTERA: CHIRONOMIDAE) IN THE LABORATORY

1973 ◽  
Vol 105 (1) ◽  
pp. 165-171 ◽  
Author(s):  
A. E. R. Downe ◽  
V. G. Caspary
Keyword(s):  
Light Intensity ◽  
Mating Behaviour ◽  
Chironomus Riparius ◽  
Volatile Chemicals ◽  
Swarming Behaviour

AbstractContinuous colonies of Chironomus riparius Meigen can be conveniently maintained in the laboratory and the swarming and mating behaviour is readily observable. Swarming is eocrepuscular and is mediated, at least in part, by light intensity and the marker stimulus. The effects of sound and volatile chemicals on the initiation and maintenance of swarming are not clearly apparent, but there is some evidence to suggest that pheromones may play a role in swarm cohesion.

Light Intensity: the Role Player in Cucumber Response to Cold Stress

2021 ◽  
Author(s):  
Tahereh Ashrestaghi ◽  
Sasan Aliniaeifard ◽  
Aida Shomali ◽  
Shiva Azizinia ◽  
Jahangir Abbasi Koohpalekani ◽  
...  
Keyword(s):  
Low Temperature ◽  
Light Intensity ◽  
Cold Stress ◽  
Low Temperatures ◽  
Warm Season ◽  
Water Soluble ◽  
Photon Flux ◽  
Soluble Carbohydrate ◽  
Dependent Manner ◽  
Biochemical Traits

Abstract Low temperatures are an important limitation for geographic distributions of warm-season crops like cucumber (Cucumis sativus L.). Tolerance to low temperatures varies among different plant species and genotypes when changes in normal environmental cues occur. To cope with low temperature, biochemical and biophysical events should be coordinated to form a physiological response. We examined how light intensity influences the effects of low temperature on photosynthesis machinery and some biochemical traits. We used chlorophyll fluorescence imaging and polyphasic fluorescence transient (OJIP) to analyze cold stress (4 ºC) damage to photosynthetic electron transport chain (ETC) under different Photosynthetic Photon Flux Densities (PPFDs; 0, 300 and 600 μmol m-2 s-1), in four accessions of cucumber. The results showed that, the negative effects of cold stress are PPFD-dependent. The adverse effect of cold stress on ETC was more pronounced in plants exposed to 600 μmol m-2 s-1 compared to the control and dark-exposed plants; indicated by disturbance in ETC and higher energy dissipation. Moreover, biochemical traits including H2O2 content, ascorbate peroxidase activity and electrolyte leakage, and water-soluble carbohydrate was increased under low temperature by increase in PPFD, while chlorophyll and carotenoid contents decreased under low temperature by PPFD elevation. Low temperature induced H2O2 accumulation via suppressing APX activity in a PPFD-dependent manner. In conclusion, high PPFDs exacerbate the adverse effects of low temperature on the cucumber seedlings.

scholarly journals Light Intensity: The Role Player in Cucumber Response to Cold Stress

Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 201
Author(s):  
Tahereh Ashrostaghi ◽  
Sasan Aliniaeifard ◽  
Aida Shomali ◽  
Shiva Azizinia ◽  
Jahangir Abbasi Koohpalekani ◽  
...  
Keyword(s):  
Electron Transport ◽  
Low Temperature ◽  
Light Intensity ◽  
Cold Stress ◽  
Ascorbate Peroxidase ◽  
Peroxidase Activity ◽  
Low Temperatures ◽  
Electron Transport Chain ◽  
Biochemical Traits ◽  
Transport Chain

Low temperatures are a substantial limitation in the geographic distribution of warm-season crops such as cucumber (Cucumis sativus L.). Tolerance to low temperatures varies among different plant species and genotypes when changes in environmental cues occur. Therefore, biochemical and biophysical events should be coordinated to form a physiological response and cope with low temperatures. We examined how light intensity influences the effects of low temperature on photosynthesis and some biochemical traits. We used chlorophyll fluorescence imaging and polyphasic fluorescence transient to analyze cold stress damage by 4 °C. Photosynthetic Photon Flux Densities (PPFDs) of 0, 300, and 600 μmol m−2 s−1, in four accessions of cucumber, were investigated. The results show that the negative effects of cold stress are PPFD-dependent. The adverse effect of cold stress on the electron transport chain is more pronounced in plants exposed to 600 μmol m−2 s−1 than the control and dark-exposed plants, indicated by a disturbance in the electron transport chain and higher energy dissipation. Moreover, biochemical traits, including the H2O2 content, ascorbate peroxidase activity, electrolyte leakage, and water-soluble carbohydrate, increased under low temperature by increasing the PPFD. In contrast, chlorophyll and carotenoid contents decreased under low temperature through PPFD elevation. Low temperature induced a H2O2 accumulation via suppressing ascorbate peroxidase activity in a PPFD-dependent manner. In conclusion, high PPFDs exacerbate the adverse effects of low temperature on the cucumber seedlings.

Mechanical Degradation of High Polymers

1961 ◽  
Vol 34 (2) ◽  
pp. 466-473
Author(s):  
F. Bueche
Keyword(s):  
Molecular Weight ◽  
Shear Rate ◽  
High Temperatures ◽  
Low Temperatures ◽  
Central Portion ◽  
Mechanical Degradation ◽  
Minor Importance ◽  
Polymer Molecules ◽  
Shear Degradation ◽  
Effect Of Oxygen

Abstract Mastication of rubbers and molten plastics often gives rise to degradation of the polymer molecules. The amount of degradation is severely dependent upon shear rate, melt viscosity, and molecular weight of the polymer, temperature, and the presence of plasticizer. Under certain conditions, usually at low temperatures, one finds that the presence of oxygen is only of minor importance. At high temperatures, at least in certain cases, shear degradation is seriously increased when oxygen is present, even though very little degradation occurs without mastication. In this latter case, oxidative scission does not appear to take place at random along the chain but seems to occur predominantly in the central portion of the chain. The purpose of this paper is to present a molecular theory which unifies these various observations. It will be restricted to the mechanical actions involved during mastication. The effect of oxygen on mechanical degradation will also be considered.

Preparation technique for cytologic study of EUS-guided FNA samples when onsite cytopathologist is absent: Cell block, smear, or both?

2011 ◽  
Vol 29 (4_suppl) ◽  
pp. 176-176
Author(s):  
N. Q. Nguyen ◽  
K. Lim ◽  
A. Ruszkiewicz
Keyword(s):  
Direct Relationship ◽  
Diagnostic Yield ◽  
Needle Aspiration ◽  
Preparation Technique ◽  
Cell Block ◽  
Solid Mass ◽  
Ancillary Studies ◽  
Tissue Material ◽  
Adequate Tissue ◽  
Cytologic Study

176 Background: Smearing EUS-guided fine-needle aspiration (FNA) samples, with or without cell block, is most commonly performed for cytologic study in centers without onsite cytology. The diagnostic yield of such technique is often low (35%-50%) and may be related to loss of diagnostic material during the smearing process. Cell block technique captures not only aspirated cells but also small tissue fragments, improving diagnostic yield and enabling additional ancillary studies. This study aimed to compare the diagnostic yield of cell block alone against conventional smear (±cell block) technique in the EUS-guided FNA evaluation of pancreatic solid mass without onsite cytological assessment. Methods: Data on the diagnostic yield of cell block alone technique performed over the last 12 months were prospectively collected and were compared to the yield of conventional smear ± cell block technique. A positive diagnostic yield was defined by the presence of adenocarcinoma and/or FNA findings consistent with the final surgical diagnosis. Results: Data were available for 96 patients, of which 66 had cell block alone and 30 had smear +/-cell block preparation. The diagnostic yield of cell block alone was significantly higher that that of smear +/- cell block (53/66 vs 13/30; P=0.003). The addition of cell block after smearing did not improve the diagnostic yield (smear: 42% vs. both: 45%, p=0.88). Of patients who had smear +/-cell block, the diagnostic yield was significantly higher when the smearing was performed by cytopathologist as compared to that by nurse (10/16 vs. 3/14, p=0.02). There was a direct relationship between the rate of diagnostic yield and the number of FNA passes performed. The yield was highest when 4 or more FNA passes was performed (85%) as compared to that of 3 passes (63%, p=0.049) and 2 or less passes (38%, p<0.0001). Conclusions: In the absence of onsite cytology services, the diagnostic yield from cell block alone was high (80%) and was superior to smear technique whether cell block was added to the evaluation of smears. In order to obtain adequate tissue material to maximise the diagnostic yield EUS-guided FNA of pancreatic mass, at least 4 FNA passes should be performed. No significant financial relationships to disclose.

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