Activity In July Research Articles

Geophysical events

Etna Volcano, Sicily, Italy (37.73°N, 15.00°E). All times are local (GMT + 2 hours). A large eruption of Etna began in early August, after a gradual buildup of activity in July [see SEAN Bulletins, 4(7‐8)]. Large explosions from the SE crater produced significant ashfalls as far as 70 km away, and lava flowed from numerous flank fissures. This eruption ended on August 9.

Premature senescence in plants along a motorway

Potted young plants of various trees and shrubs (clones), exposed in the vicinity of a motorway, showed premature senescence. Investigations with two species, birch Betula pendula and sallow thorn Hippophae rhamnoides, showed that peroxidase activity in July and September, and ethylene production during autumnal senescence, were significantly increased. Premature leaf abscission was observed in all investigated trees and shrubs (ash Fraxinus excelsior, birch Betula pendula Roth, dogwood Cornus sanguinea, honeysuckle Lonicera xylosteum, oak Quercus robur and sallow thorn Hippophae rhamnoides) along the motorway. It is supposed that consitions associated with traffic are responsible for these effects. Slight salinity in the soil of the pots had no significant effect.

Annual reproductive rhythm and ovulation rate in four fat-tailed sheep breeds

ABSTRACTKarakul, Mehraban, Naeini and Bakhtiari sheep were checked twice a day for oestrus using aproned rams and were laparotomized within 5 to 16 h of the end of every second oestrous period. Oestrus was observed for 12 monthly periods commencing on 21 April.The Mehraban breed with 1 -6 oestrous periods per month was less seasonal in its breeding activity (P<0·01) than the other breeds. Four-year-old ewes were more sexually active (P<0·01) than 3-year-old ewes (1·48 v. 1·28 oestrous periods per month). Seasonal variation in the sexual activity of the ewes was observed (P<001); the peak of activity in July to January was followed by a steady decline in February and March to a low in April and May, and then a steep recovery phase in June. There was only limited sexual activity for at least 4 months (March to June).The overall mean cycle length was 17·8 days (14 to 23 days), and the means for the four breeds were 17·6, 17·8, 17·8 and 17·9. The oestrous cycle was longer (P<0·05) during the period from December t o February than during that from June to August.The overall mean duration of the oestrous period was 36·9 h and the means for the four breeds were 35·2, 38·0, 37·4 and 37·1 h, respectively (P<0·05). The duration showed some monthly variation (P<0·01) but did not follow a special seasonal pattern. The ovulation rates for the four breeds were 1·07, 1·13,0·94 and 0·95 respectively, (P<0·01). There was a non-significant decline in the mean ovulation rate from March to June. Right ovaries were more active than left ovaries as judged by the observation of a higher average number of corpora lutea per ewe per laparotomy (0·58 v. 0·43, P<001).

Low Preferred Foraging Temperatures and Nocturnal Foraging in a Desert Harvester Ant

Previous articleNext article No AccessLetters to the EditorsLow Preferred Foraging Temperatures and Nocturnal Foraging in a Desert Harvester AntGeorge L. Hunt, Jr.George L. Hunt, Jr. Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 111, Number 979May - Jun., 1977 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/283187 Views: 4Total views on this site Citations: 3Citations are reported from Crossref Copyright 1977 The University of ChicagoPDF download Crossref reports the following articles citing this article:Christina L. Kwapich and Bert Hölldobler Destruction of Spiderwebs and Rescue of Ensnared Nestmates by a Granivorous Desert Ant (Veromessor pergandei), The American Naturalist 194, no.33 (Jul 2019): 395–404.https://doi.org/10.1086/704338Avalon C. S. Owens, Sara M. Lewis The impact of artificial light at night on nocturnal insects: A review and synthesis, Ecology and Evolution 8, no.2222 (Oct 2018): 11337–11358.https://doi.org/10.1002/ece3.4557D. Gillon, F. Adam, B. Hubert Production et consommation de graines en milieu sahélo-soudanien au Sénégal les fourmis,Messor galla, Insectes Sociaux 31, no.11 (Mar 1984): 51–73.https://doi.org/10.1007/BF02223692

The employment of newly qualified physicists 1969–70

The collection and analysis of first employment statistics on behalf of the Royal Society/Institute of Physics working party on physics and industry must seem to those university physicists who have supplied the information to have become an annual event. When the working party concludes its activities in July, these data will have covered the five year period 1965/66–1969/70 for employment of PhDs and the two year period 1968/69–1969/70 for new graduates.

Observations of solar flare radiation and modulation effects at balloon altitudes, July 1959

Observations of cosmic-ray time variations in the stratosphere were obtained over Berkeley, Calif. (USA), and Lindau/Harz (Germany) during the period of outstanding solar activity in July 1959. Whereas over Berkeley (geomagnetic latitude 44 deg N) only modulation of cosmic radiation by solar- controlled processes was observed, additional radiation accelerated in the vicinity of the sun (approximately 46% above normal) was observed over Lindau (geomagnetic latitude 52 deg N) on July 15. On the assumption that the excess radiation consisted almost entirely of protons, its energy spectrum had the form N(E)dE approximately E-4 dE and extended up to 400 Mev. According to conventional geomagnetic theory, individual protons of these energies are normally forbidden at geomagnetic latitude 52 deg N. Their presence over Lindau on July 15 indicates that they were admitted by some mechanism which temporarily lowers the cutoff rigidity at this latitude during a magnetic storm. There is some indication of further examples of excess radiation over Lindau at atmospheric depths down to 30 mm Hg on July 13, 21, 23, and 31.

Southern Hemisphere Meteor Shower Activity in July and August

Observations of the radiant positions and the activities of the 3-Aquarids and three minor showers of July and August, obtained with high resolution radio equipment at Adelaide from 1957 to 1959, are given in detail. Data for the 3-Aquarids are combined with similar observations in 1953 to obtain the radiant ephemeris

Seasonal Variation in the Activity of the Thyroid Gland of Yearling Brown Trout Salmo Trutta Linn

ABSTRACT Seasonal variations in the activity of the thyroid gland in yearling brown trout were measured by two methods ; first, by the changes in thyroid epithelial cell height and, secondly, by the rate of loss of radio-iodine from the gland. Peak thyroid activity was found to occur in spring with a second peak demonstrable by the radio-iodine technique in mid-summer. With the exception of this short burst of activity in July, the activity of the thyroid was found to be inversely proportional to the water temperature. It is suggested that the thyroid is concerned in a temperature-compensating mechanism. It is suggested that the rate of change of the thyrotropic hormone level in the blood determines the mode of response of the gland.