Field observations and laboratory studies of some Antarctic cold desert cryptogams

1972 ◽  
pp. 97-142 ◽  
Author(s):  
Edmund Schofield ◽  
Vernon Ahmadjian
Keyword(s):  
Field Observations ◽  
Laboratory Studies ◽  
Cold Desert

A new species of Hypatima Hübner (Lepidoptera: Gelechiidae) injurious to mango trees in East Africa

1989 ◽  
Vol 79 (3) ◽  
pp. 411-420 ◽  
Author(s):  
K. Sattler ◽  
A. B. Stride
Keyword(s):  
Life History ◽  
New Species ◽  
East Africa ◽  
Female Genitalia ◽  
Field Observations ◽  
Laboratory Studies ◽  
Male And Female ◽  
Extensive Field ◽  
A New Species

AbstractHypatima mangiferae Sattler sp. n. is described from Kenya, where its larva is injurious to commercial mango trees. A description of its life-history, based on extensive field observations and laboratory studies, is also provided. The moth, its male and female genitalia and the damage caused by the larva are illustrated.

scholarly journals A Parameterization of Sticking Efficiency for Collisions of Snow and Graupel with Ice Crystals: Theory and Comparison with Observations*

2015 ◽  
Vol 72 (12) ◽  
pp. 4885-4902 ◽  
Author(s):  
Vaughan T. J. Phillips ◽  
Marco Formenton ◽  
Aaron Bansemer ◽  
Innocent Kudzotsa ◽  
Barry Lienert
Keyword(s):  
Probability Distribution ◽  
Kinetic Energy ◽  
Ice Crystals ◽  
Field Observations ◽  
Laboratory Studies ◽  
Atmospheric Models ◽  
Vapor Growth ◽  
Collision Processes ◽  
Work Done ◽  
Temperature Surface

Abstract A new parameterization of sticking efficiency for aggregation of ice crystals onto snow and graupel is presented. This parameter plays a crucial role for the formation of ice precipitation and for electrification processes. The parameterization is intended to be used in atmospheric models simulating the aggregation of ice particles in glaciated clouds. It should improve the ability to forecast snow. Based on experimental results and general considerations of collision processes, dependencies of the sticking efficiency on temperature, surface area, and collision kinetic energy of impacting particles are derived. The parameters have been estimated from some laboratory observations by simulating the experiments and minimizing the squares of the errors of the prediction of observed quantities. The predictions from the new scheme are compared with other available laboratory and field observations. The comparisons show that the parameterization is able to reproduce the thermal behavior of sticking efficiency, observed in published laboratory studies, with a peak around −15°C corresponding to dendritic vapor growth of ice. Finally, a new theory of sticking efficiency is proposed. It explains the empirically derived parameterization in terms of a probability distribution of the work that would be required to separate two contacting particles colliding in all possible ways among many otherwise identical collisions of the same pair with a given initial collision kinetic energy. For each collision, if this work done would exceed the initial collision kinetic energy, then there is no separation after impact. The probability of that occurring equals the sticking efficiency.

scholarly journals Oxidation of atmospheric reduced sulphur compounds: perspective from laboratory studies

1997 ◽  
Vol 352 (1350) ◽  
pp. 171-182 ◽  
Author(s):  
A. R. Ravishankara ◽  
Yinon Rudich ◽  
Ranajit Talukdar ◽  
Stephen B. Barone
Keyword(s):  
Boundary Layer ◽  
Laboratory Experiments ◽  
Marine Boundary Layer ◽  
Field Observations ◽  
Dimethyl Sulphide ◽  
Laboratory Studies ◽  
Sulphur Compounds ◽  
Complex Sequence ◽  
End Products ◽  
Reduced Sulphur Compounds

Results of laboratory experiments which address the course of the OH + DMS (dimethyl sulphide) reaction in the atmosphere are presented. It is shown that OH reacts via a complex sequence of reactions to produce CH 3 S and other products, and argued that NO 3 is unlikely to be an important oxidizer of DMS in the marine boundary layer (MBL) because it is very efficiently taken up by water droplets. A simplified mechanism for the oxidation of DMS in the troposphere is presented. This mechanism explains some of the field observations on the end products of DMS oxidation and their variations with temperature.

MCPA Synergizes Imazamox Control of Feral Rye (Secale cereale)

2011 ◽  
Vol 25 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Andrew R. Kniss ◽  
Drew J. Lyon ◽  
Joseph D. Vassios ◽  
Scott J. Nissen
Keyword(s):  
Ammonium Phosphate ◽  
Dry Weight ◽  
Field Studies ◽  
Field Observations ◽  
Laboratory Studies ◽  
Fertilizer Rate ◽  
Initial Field ◽  
Spray Solution ◽  
Treated Leaf ◽  
Feral Rye

Field, greenhouse, and laboratory studies were conducted to determine the effect of MCPA ester, fertilizer type, and fertilizer rate on feral rye control with imazamox. In field studies near Sidney, NE, increasing the concentration of liquid ammonium phosphate (10–34–0) from 2.5 to 50% of the spray solution decreased feral rye control with imazamox by as much as 73%. Conversely, adding MCPA ester to imazamox significantly increased feral rye control in field studies by up to 77%. Initial greenhouse studies confirmed the liquid ammonium phosphate antagonism effect, but subsequent greenhouse studies were inconsistent with regard to the interaction between fertilizer and imazamox. At least one source of liquid ammonium phosphate was shown not to be antagonistic, and therefore fertilizer source or contaminants may be responsible for initial field observations. Greenhouse studies confirmed the synergistic interaction between MCPA and imazamox. MCPA ester applied at 560 g ai ha−1 decreased the rate of imazamox required to cause 50% reduction in feral rye dry weight (GR50) to 13 g ha−1 compared to 35 g ha−1 for imazamox alone. Although addition of MCPA ester increased 14C-imazamox absorption by 8% in laboratory studies, less 14C translocated out of the treated leaf; therefore the mechanism of synergism does not appear to be related to imazamox absorption or translocation.

Ecology of Benthic Foraminifera

1982 ◽  
Vol 6 ◽  
pp. 37-50
Author(s):  
Barun K. Sen Gupta
Keyword(s):  
Benthic Foraminifera ◽  
Common Species ◽  
Continental Margins ◽  
Field Observations ◽  
Laboratory Studies ◽  
Geographic Locations ◽  
Water Mixing ◽  
Marine Habitats ◽  
Effects Of Temperature ◽  
Depth Zonation

Benthic foraminifera live in a wide variety of marine habitats, from marshes to abyssal plains. Both epifaunal and infaunal adaptations are present. The distribution of species is controlled by a complex of abiotic and biotic variables of the environment, usually resulting in a depth-zonation of assemblages on continental margins.The composition of the substrate may have a direct or indirect influence on the constitution of the assemblage. Laboratory studies and field observations demonstrate the effects of temperature and salinity variations, particularly on nearshore species. Many calcareous species have algal or chloroplast symbionts; their distribution is partly controlled by light tolerance.Benthic foraminifera are omnivorous and feed mainly by the pseudopodia. Large supply of nutrients, as in areas of upwelling or water mixing, may give rise to large blooms of opportunistic species.Marine marshes of diverse geographic locations support some common species. Deep bathyal or abyssal species are widespread, but dominance patterns are apparently associated with identifiable water masses, although causal relations are unclear.

Commentaries on the Huttonian Theory of the Earth From Transactions of the Royal Society of Edinburgh, 1805-1815

1983 ◽  
Vol 2 (1) ◽  
pp. 28-34
Author(s):  
Peter Bretsky
Keyword(s):  
Royal Society ◽  
18Th Century ◽  
Turn Of The Century ◽  
Field Observations ◽  
Laboratory Studies ◽  
Earth History ◽  
Geological Processes ◽  
The Earth ◽  
Geomorphic Features ◽  
High Level

Articles published from 1805 to 1815 in the Transactions of the Royal Society of Edinburgh reflect a rapidly emerging and meticulous empiricism in the study of earth history; an empiricism directed principally toward an understanding of James Hutton's notions about cyclical, igneous-based, earth processes. One obvious focus for this detailed testing was Hutton's disagreement with Werner over the origin of basalt, which was most carefully explored in the laboratory studies of Sir James Hall and Robert Kennedy. However the geological field observations of Sir George Mackenzie, Lord Webb Seymour, John Playfair and other Society members seemed also to play a most important role in deciphering the Huttonian logic. Hall, following Lavoisier but in disagreement with Hutton, repeatedly emphasized that a more rigorous experimental micro-chemistry would eventually result in a more fundamentally sound macrogeology. In a number of papers read before the Royal Society it was obvious that Hall and his colleagues were indebted to Hutton for his demanding brand of field empiricism, which they acclaimed as a break with the less rigorous 18th century cosmologies, but Hutton was definitely not venerated. Certain Huttonian conclusions were verified but others were severely compromised not only by the results of Hall's fusion experiments but also by numerous field observations especially of Alpine geomorphic features. Indeed, attempting to understand the scale of geological processes through their subsequent effects appears at times to have been a more fundamental pursuit than a continual chorus of fire versus water. Obscured perhaps by the studies of subsequent generations these turn-of-the-century geological controversies were so enriched by empirical fervor that even this brief perusal of the Transactions cannot fail to impress us with the high level of imaginative experimentation devised by members of the Society, experimentation, however, resulting in large part from the Huttonian legacy.

Pre-mating Blood Feeding by Anopheles pharoensis (Diptera: Culicidae) and Its Effects on Mating, Longevity and Egg Production

1990 ◽  
Vol 25 (1) ◽  
pp. 57-63
Author(s):  
Adel S. El-Akad ◽  
J. G. Humphreys
Keyword(s):  
Blood Meal ◽  
Egg Production ◽  
Ovarian Development ◽  
Reproductive Potential ◽  
Blood Feeding ◽  
Field Observations ◽  
Laboratory Studies ◽  
The Third ◽  
Anopheles Pharoensis ◽  
Blood Meals

Field observations and laboratory studies were conducted to determine the effects of a pre-mating blood meal on mating, ovarian development and oviposition in Anopheles pharoensis (Theobald). Approximately 24% of the females blood feed before mating; however, swollen abdomens of blood-fed females interfere with the mating process. In females which mated prior to first blood meal, first oviposition occurred at 6.6 days and required only a single blood meal. A second blood meal takes them to the second oviposition in an additional 2.5 days; the third oviposition required 1.4 blood meals and occurred 3 days after the second oviposition. Blood-fed unmated females reach first oviposition at 13.4 days and require an average of 4 blood meals prior to the first oviposition. At this age, the female is chronologically old and even if mating now occurs, egg production is greatly reduced and continues to decrease through subsequent ovipositions until death. The taking of a blood meal prior to mating greatly decreases the reproductive potential of this species.

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