Foraging for mates in the hyperparasitic wasp, Dendrocerus carpenteri: impact of unfavourable weather conditions and parasitoid age

Oecologia ◽  
1999 ◽  
Vol 119 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Ulrich Schwörer ◽  
Wolfgang Völkl ◽  
Klaus H. Hoffmann
Keyword(s):  
Weather Conditions ◽  
Unfavourable Weather ◽  
Parasitoid Age

scholarly journals Weather Risk Management in Agriculture

2016 ◽  
Vol 64 (4) ◽  
pp. 1303-1309 ◽  
Author(s):  
Martina Bobriková
Keyword(s):  
Financial Risk ◽  
Weather Conditions ◽  
Option Hedging ◽  
Put Option ◽  
Hedging Strategies ◽  
Weather Risk ◽  
High Volatility ◽  
Unfavourable Weather ◽  
Agricultural Industries ◽  
Weather Risk Management

The paper focuses on valuation of a weather derivative with payoffs depending on temperature. We use historical data from the weather station in the Slovak town Košice to obtain unique prices of option contracts in an incomplete market. Numerical examples of prices of some contracts are presented, using the Burn analysis. We provide an example of how a weather contract can be designed to hedge the financial risk of a suboptimal temperature condition. The comparative comparison of the selected option hedging strategies has shown the best results for the producers in agricultural industries who hedges against an unfavourable weather conditions. The results of analysis proved that by buying put option or call option, the farmer establishes the highest payoff in the case of temperature decrease or increase. The Long Straddle Strategy is the most expensive but is available to the farmer who hedges against a high volatility in temperature movement. We conclude with the findings that weather derivatives could be useful tools to diminish the financial losses for agricultural industries highly dependent for temperature.

The Use of Barometric Charts in the Navigation of Airships

1927 ◽  
Vol 31 (193) ◽  
pp. 60-80
Author(s):  
Norman L. Silvester
Keyword(s):  
Weather Conditions ◽  
Landing Gear ◽  
Unfavourable Weather ◽  
Bad Weather

Experience has shown how dependent is the airship upon weather conditions —more particularly for a safe ascent and descent. The numerous experiments with windscreens, tractors, mooring posts and landing gear emphasise the difficulty of handling an airship on the ground and of manoeuvring it in and out of its shed.It is in the endeavour to minimise these risks that this study has been undertaken. In the discussion as to the most advisable course for an airship to adopt for its own safety when surprised by unfavourable weather, it should be remembered that in all the examples which follow, it is a case of “making the best of a bad job”; and that no pilot would wittingly leave his base with the knowledge of such bad weather impending except under pressure of war time necessity. It is hoped to demonstrate that in some cases it might be possible by skilful navigation, aided by the frequent communication of isobaric charts by wireless telegraphy and by accurate positions given frequently by the same means, for a pilot to keep in the air during the passage of bad weather and thus avoid the risk of wreck by attempting a premature landing.

scholarly journals The Ticks of Rodents and their Nests, and the Discovery that Rhipicephalus sanguineus Latr. is the Vector of Tropical Typhus in Kenya

1935 ◽  
Vol 35 (1) ◽  
pp. 1-22 ◽  
Author(s):  
J. Isgaer Roberts
Keyword(s):  
Guinea Pig ◽  
Positive Result ◽  
Guinea Pigs ◽  
Rhipicephalus Sanguineus ◽  
Weather Conditions ◽  
Human Beings ◽  
Negative Results ◽  
Unfavourable Weather ◽  
The Subject ◽  
Made In

1. Earlier attempts to trace the vector of tropical typhus in Kenya failed. The only references to the subject in the available literature consist of mere suggestions that a mite would most likely prove to be the transmitter.2. An investigation made in an area whence most Nairobi cases of tropical typhus were reported, suggested that a tick (R. pulchellus) would be the most likely vector.3. Transmission experiments made in the belief that one of the unclassed fevers of man was conveyed by R. pulchellus have so far yielded negative results. There is, however, sufficient circumstantial evidence available pointing to this tick as vector of a form of mild typhus to man—this demands further investigation.4. At Mombasa and Nairobi, houses reported to be heavily infested with ticks, or houses investigated after the occurrence of the tropical typhus in them, have yielded only R. sanguineus.5. R. sanguineus (3 ♀), taken from a dog in a house where the last typhus case had occurred 8 months previously, gave a typical typhus syndrome when emulsified and inoculated into a male guinea-pig. R. sanguineus (1 ♀, 12 ⊙), taken in a house where a child had recently contracted typhus, also gave a positive result with guinea-pigs and the virus was further transmitted by passage through other guinea-pigs.6. The infestation of houses by R. sanguineus and the incidence of tropical typhus among human beings appear to be influenced by unfavourable weather conditions, causing the ticks to seek relatively dry and warm places for purposes of oviposition or metamorphosis, thus invading houses. In the absence of dogs, its usual hosts, the tick attacks man.

scholarly journals Complex evaluation of agrotechnical factors in rape seed

2010 ◽  
pp. 59-63
Author(s):  
Zoltán Kátai
Keyword(s):  
Weather Conditions ◽  
Research Area ◽  
Research Centre ◽  
Crop Failure ◽  
Sowing Time ◽  
Homogeneous Surface ◽  
Mild Winter ◽  
Cultivation Systems ◽  
Complex Evaluation ◽  
Unfavourable Weather

A polifactorial field trial with rape was carried out in the crop-years of 2007/2008 and 2008/2009 at the Látókép Research Centre of University of Debrecen, 15 km away from Debrecen. The soil type of the research area was a calcaric chernozem, with a levelled and homogeneous surface. Our investigations on the dynamics of lodging proved that rape can easily be lodged under unfavourable weather conditions, which results in a significant crop failure: In crop-year 2009 yields were 1.0-1.5 t ha-1 higher than in 2008, when the weather conditions were more unfavourable. In both crop-years the influence of sowing time on the crop yield of rape was examined in three soil cultivation systems, with ploughing, loosening or disking. Different sowing time influenced the yield of rape in both crop-years significantly. In the crop-year of 2007/2008 – due to mild winter – we got the highest yield in the first sowing time (at the end of August) with loosening (3930 kg ha-1) and disking (3727 kg ha-1), while in case of ploughing we experienced the highest yield (3770 kg ha-1) in the second sowing time. There were no significant differences between the first and second sowing time (the end of August and the beginning of September), and in the third sowing time (end of September) also a moderate crop failure (-6.7%) cold be obtained, due to the favourable weather in winter and the water supply of the crop-year 2007/2008. In 2008/2009 all the three cultivation systems showed the best yield-results in the second sowing time (ploughing: 4886 kg ha-1, loosening: 5186 kg ha-1, disking: 5090 kg ha-1), and the first sowing time hardly differed from this (-4.1%), while the late September sowing time resulted in a significant crop failure of -11.1%.

scholarly journals Assessing the risk of stigma clogging in strawberry flowers due to pollinator sharing with oilseed rape

2017 ◽  
Vol 21 ◽  
Author(s):  
Lina Herbertsson ◽  
Ida Gåvertsson ◽  
Björn K Klatt ◽  
Henrik G Smith
Keyword(s):  
Oilseed Rape ◽  
Weather Conditions ◽  
Pollination Success ◽  
Ripening Time ◽  
Flower Visitation ◽  
Negative Effect ◽  
Potential Negative Effect ◽  
Unfavourable Weather ◽  
Pollinator Sharing ◽  
Weight Number

Strawberry and oilseed rape are economically important and co-flowering insect-pollinated crops that may affect each other via shared pollinators. One potential negative effect of pollinator sharing is stigma clogging, i.e. that pollen from one plant species covers the stigma and prevents pollination in the other. We tested if application of oilseed rape pollen on strawberry receptacles reduces pollination with subsequent effects on strawberry weight, number of malformations and ripening time. We simulated real pollination situations by using dead bees mounted on toothpicks to mimic flower-visitation of foraging bees. Six strawberry flowers, usually on different plant individuals, were hand-pollinated sequentially per simulated foraging bout. In half of these foraging bouts, we started with an oilseed rape flower, and in those foraging bouts the proportion oilseed rape pollen was expected to decline with increasing number of visited strawberry flowers. Oilseed rape pollen had no effect on any of the tested variables. Increasing number of previously visited strawberry flowers in the simulated foraging bout enhanced the number of developed achenes, but this was marginally non-significant when accounting for the total number of achenes. Strawberry weight increased and ripening time decreased with increasing number of pollinated achenes, whereas none of the tested factors had any effect on the number of malformations. Our results have implications for strawberry farmers, because shortened ripening time could reduce the risk of yield loss from pests, diseases and unfavourable weather conditions. In addition, we show that oilseed rape pollen is unlikely to disturb pollination success of strawberry flowers.

scholarly journals Winter Roost Tree Selection and Phenology of the Long-Eared Owl (Asio otus) in Crimea

Diversity ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 105
Author(s):  
Volodymyr Kucherenko ◽  
Pavel Kalinovsky
Keyword(s):  
Inverse Relationship ◽  
Weather Conditions ◽  
Convex Curve ◽  
Deciduous Trees ◽  
Temperature Decrease ◽  
Short Term ◽  
Maximum Daily Temperature ◽  
Temperature Changes ◽  
Unfavourable Weather ◽  
The Mean

The winter roost of the long-eared owl Asio otus in Crimea (South of Ukraine), located in Simferopol, is described. In 2015–2017, the number of long-eared owls varied on a convex curve, with the maximum reached at the end of November and in December. The birds exhibited a strong preference for roosting in conifers, where we recorded 89% of the owls. There was an inverse relationship between the mean of the maximum daily temperature (°C) and the number of owls in both seasons. The owls were not sensitive to abrupt but short-term temperature changes, but the temperature decrease curve caused practically synchronous changes in the dynamics of bird numbers. It was found that the number of owls significantly differed based on weather conditions in 16 trees. The proportion of owls sitting on coniferous trees increased with unfavourable weather, and the converse pattern was observed for deciduous trees.

Students’ trip mode choice in favourable and unfavourable weather conditions

2019 ◽  
pp. 1-8
Author(s):  
Mirbahador Yazdani ◽  
Mahsa Jafari ◽  
Shiva Yazdani ◽  
Elahe Raouf ◽  
Mahsa Shokrzadeh
Keyword(s):  
Mode Choice ◽  
Weather Conditions ◽  
Unfavourable Weather

Photogrammetric processing and application of multi-temporal satellite imagery stereopairs

2021 ◽  
Vol 974 (8) ◽  
pp. 36-44
Author(s):  
R.V. Permyakov
Keyword(s):  
High Resolution ◽  
Satellite Imagery ◽  
Weather Conditions ◽  
3D Models ◽  
High Resolution Imagery ◽  
Multi Temporal ◽  
Unfavourable Weather ◽  
High Resolution Satellite Imagery ◽  
Very High Resolution Imagery ◽  
Very High

Stereopairs of very-high resolution satellite imagery constitute one of the key high-accurate data sources on heights. A stereophotogrammetric technique is a key method of processing these data. Despite that a number of spacecrafts gathering very-high-resolution imagery in a stereo mode constantly increases, the area of the Earth regularly covered by such data and stored in the archives of RSD operators remains relatively small and, as a rule, is limited only to large urban agglomerations. The new collection may not suit the customer for several reasons. Firstly, the materials of the new stereo collection are more expensive than those of the archived one. Secondly, due to unfavourable weather conditions and a busy schedule of satellites, the completion of the new collection may go beyond the deadline specified by the customer. Well known and brand-new criteria to form multi-temporal, stereopairs are analyzed. The specific of photogrammetric processing multi-temporal stereopairs is demonstrated. Application of multi-temporal stereopairs is described. In conclusion it is confirmed that 3D-models and high accurate DTMs can be generated basing on stereo models from multi-temporal satellite imagery in the absence of the following data

scholarly journals Foraging opportunism and feeding frequency in the red-footed falcon (Falco vespertinus) in Slovakia: case study from 2017

2017 ◽  
Vol 11 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Jozef Chavko ◽  
Anton Krištín
Keyword(s):  
Bird Species ◽  
Weather Conditions ◽  
Food Composition ◽  
Feeding Frequency ◽  
Adverse Weather Conditions ◽  
Rainy Weather ◽  
Adverse Weather ◽  
Negative Effect ◽  
Unfavourable Weather ◽  
Falco Vespertinus

Abstract Foraging opportunism and feeding frequency are less studied parameters of behaviour in insectivorous falcons, many of which are endangered bird species. In this short study, prey composition and feeding frequency of red-footed falcon (Falco vespertinus) nestlings were studied using the method of camera recordings during seven days in July 2017 in southwestern Slovakia. Camera recording analyses of 2–3 chicks (14–26 days old) in three nests revealed a significant preference for insects (97%, n = 305 prey items), of which the Italian locust (Calliptamus italicus) was highly predominant (54%). We also found very high average chick feeding frequency (9.9 feedings per hour, n = 29 hours 22 min of regular observations), whereby the females fed their young ones more frequently (64.9%, n = 305 feedings) than the males (35.1%). Analyses of food composition in adverse weather conditions showed that unfavourable weather had a negative effect on chick feeding frequency, and in rainy weather the males fed significantly less than the females.

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