scholarly journals Occurrence of Drosophilids in the Pernambuco’s coastal region (years 2000-2001) and the Frequency of chromosomal inversions found in Drosophila malerkotliana

2020 ◽  
Author(s):  
Pierre Teodósio Félix ◽  
José Ferreira dos Santos
Keyword(s):  
Charles Darwin ◽  
Coastal Region ◽  
Average Frequency ◽  
Genetic Variations ◽  
Great Distance ◽  
Distribution Center ◽  
Frequency Of Occurrence ◽  
Chromosomal Inversions ◽  
Drosophila Malerkotliana ◽  
Colonization Time

AbstractDrosophilids were collected in the campus of UFPE (Recife), Rio Doce (Olinda), Vila Velha (Itamaracá), Parque de dois Irmãos (Recife) and Charles Darwin Ecological Refuge (Igarassu), in the years 2000 and 2001, seeking to establish the frequency of occurrence of the various species of the genus Drosophila. In these collections, D. malerkotliana occurred in an average frequency of 64%, followed by D. melanogaster, with an average frequency of 23%. The frequency of D. malerkotliana was higher than that of D. melanogaster in localities with high and medium degree of urbanization. Despite the great distance from the distribution center of the species (Africa), D. malerkotliana presented high polymorphism of chromosomal inversions. In the locality of Rio Doce, inversions In(IIL)24B-39A and In(IIL)21-25, occurred with frequencies of 18.5% and 100%, respectively, while inversion In(IIIR)84-88B occurred with a frequency of 100%. In the population of campus UFPE (Recife), also with high urbanization, two inversions were found, In(IIIR)93C-94A and In(IIIL)64A-72A with frequencies of 37.1 and 60%, respectively. In the population of The Parque de Dois Irmãos (Recife), with medium urbanization, four inversions were visualized: In(IIIL)70C-73B (66%); In(IIIR)93C-94A (52%); In(IIL)24B-39A (33%); and In(IIR)50B-51A (33%). In the population of the Charles Darwin Ecological Refuge (Igarassu), of low urbanization, only the inversion In(IIIR)100A-98B(?) was found. −88(?), with 100% frequency. These data suggest that the polymorphism of inversions is higher in localities with greater urbanization, possibly due to the longer colonization time, which allowed the accumulation of genetic variations.

The Distribution of Chaetognatha in the Gulf of Alaska in 1954 and 1956

1959 ◽  
Vol 16 (3) ◽  
pp. 351-361 ◽  
Author(s):  
Paul N. Sund
Keyword(s):  
Coastal Region ◽  
Gulf Of Alaska ◽  
Inland Waters ◽  
San Juan ◽  
Frequency Of Occurrence ◽  
Subarctic Region ◽  
Saline Waters ◽  
Hydrographic Features

Zooplankton collections from two cruises to the Gulf of Alaska during 1954 and 1956 were studied to determine the species of Chaetognatha present, to establish their distribution within those waters, and to consider the distribution of the species with regard to certain general hydrographic features prevalent in the region at the time the collections were made. Also considered were a few collections made during the summer of 1958 in the waters surrounding San Juan Island in the San Juan Archipelago, Washington.The general oceanographic features of the Gulf of Alaska are described. The distributions and frequency of occurrence of 3 species of 2 genera of chaetognatha are described and discussed. Eukrohnia hamata is found at most off-shore stations, diminishing in number nearer the coast in less saline waters. Sagitta elegans is apparently cosmopolitan in the areas studied. S. lyra an oceanic form, was found in regions influenced by waters of the Subarctic Region and the American Coastal Region. The presence of S. lyra in inland waters of the San Juan Archipelago during the summer of 1958 is considered to be an indication of the shoreward movement of oceanic waters.

scholarly journals Anomalous needle numbers on dwarf shoots of Pinus mugo and P. uncinata (Pinaceae)

2011 ◽  
Vol 72 (2) ◽  
pp. 139-148 ◽  
Author(s):  
Krystyna Boratyńska ◽  
Adam Boratyński
Keyword(s):  
Iberian Peninsula ◽  
Central Europe ◽  
Average Frequency ◽  
Range Limits ◽  
Frequency Of Occurrence ◽  
Pinus Mugo ◽  
Central European ◽  
Elevational Range ◽  
Two Populations

The frequency of occurrence of abnormal, three- (or more) needle dwarf shoots of most southern and central European two-needle pine (<em>Pinus</em>) species were studied. No specimens with more than two-needle dwarf shoots were found in a population of <em>P. nigra </em>Arnold subsp. <em>salzmannii </em>(Dunal) Franco from the Iberian Peninsula and in two populations of <em>P. uliginosa</em> Neumann from the Sudeten Mountains in Central Europe. Single specimens were found within one population of <em>P. pinaster </em>Aiton from the Iberian Peninsula and among six populations of <em>P. sylvestris </em>L. from the Iberian Peninsula and Central Europe. Abnormal dwarf shoots mostly with three, but also four, five or six needles were found among 24 of 25 surveyed populations of <em>P. mugo </em>Turra and <em>P. uncinata </em>Ramond. The average frequency of specimens with at least one three-needle dwarf shoot was 24% for <em>P. mugo</em> and 20% for <em>P. uncinata</em>. The frequencies of occurrence varied significantly among studied populations and were highest in samples collected from the upper elevational range limits of the species in the mountains and near the northern limits of their ranges. The frequency of abnormal dwarf shoots in the same populations was significantly high in 2-3 consecutive years. Needles from three-needle dwarf shoots were not significantly shorter than those of two-needle shoots.

Patterns of Aerial Photo Weather in Canada

1971 ◽  
Vol 25 (1) ◽  
pp. 42-48
Author(s):  
J. FLEMING
Keyword(s):  
Average Frequency ◽  
Aerial Survey ◽  
Observation Data ◽  
Frequency Of Occurrence ◽  
Mean Values ◽  
Solar Altitude ◽  
Weather Patterns ◽  
The Mean ◽  
Single Figure ◽  
Weather Observation

Weather suitable for high altitude aerial survey photography is defined in terms of cloud cover, horizontal visibility, and solar altitude. With these criteria established, relevant weather observation data, stored in the electronic archives of the Meteorological Service of Canada, were selected and used to compute a single figure value of average frequency of occurrence for each observation station, each month, for each of two minimum solar altitudes. Isopleths were then plotted on suitable base maps to depict the mean frequency of occurrence of observations meeting the criteria over a 10-year period. During the study of the accumulated data, it became apparent that four major areas which exhibit distinctive zonal photo weather patterns are to be found in Canada. Possible reasons for the existence of these zonal distributions are discussed in terms of their regional and local, geographical and meteorological characteristics. The information presented is statistical. Because of the nature of the computer program used to select data it was, unfortunately, not possible to compute standard deviations from mean values. This and other limitations on the application of the data to specific cases are discussed.

scholarly journals On the Relationship between Circulation Patterns, the Southern Annular Mode, and Rainfall Variability in Western Cape

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 753
Author(s):  
Chibuike Chiedozie Ibebuchi
Keyword(s):  
South Africa ◽  
High Probability ◽  
Climate Models ◽  
Rainfall Variability ◽  
Principal Component ◽  
Southern Annular Mode ◽  
Average Frequency ◽  
Frequency Of Occurrence ◽  
Western Cape ◽  
Annular Mode

This study investigates circulation types (CTs) in Africa, south of the equator, that are related to wet and dry conditions in the Western Cape, the statistical relationship between the selected CTs and the Southern Annular Mode (SAM), and changes in the frequency of occurrence of the CTs related to the SAM under the ssp585 scenario. Obliquely rotated principal component analysis applied to sea level pressure (SLP) was used to classify CTs in Africa, south of the equator. Three CTs were found to have a high probability of being associated with wet days in the Western Cape, and four CTs were equally found to have a high probability of being associated with dry days in the Western Cape. Generally, the dry/wet CTs feature the southward/northward track of the mid-latitude cyclone, adjacent to South Africa; anti-cyclonic/cyclonic relative vorticity, and poleward/equatorward track of westerlies, south of South Africa. One of the selected wet CTs was significantly related to variations of the SAM. Years with an above-average SAM index correlated with the below-average frequency of occurrences of the wet CT. The results suggest that through the dynamics of the CT, the SAM might control the rainfall variability of the Western Cape. Under the ssp585 scenario, the analyzed climate models indicated a possible decrease in the frequency of occurrence of the aforementioned wet CT associated with cyclonic activity in the mid-latitudes, and an increase in the frequency of the occurrence of CT associated with enhanced SLP at mid-latitudes.

Electric Field Induced Light Emission and Conductance-Loss Transients in Liquid Anthracene

1974 ◽  
Vol 52 (20) ◽  
pp. 3559-3561 ◽  
Author(s):  
Kyoji Shinsaka ◽  
Gordon R. Freeman
Keyword(s):  
Electrical Conductivity ◽  
Electric Field ◽  
Semiconductor Laser ◽  
Laser Emission ◽  
Light Emission ◽  
Average Frequency ◽  
Frequency Of Occurrence ◽  
High Electrical Conductivity ◽  
Field Strengths

Liquid anthracene has an unusually high electrical conductivity for a hydrocarbon, being 2 × 10−1 mho cm−1 at 507 K. At electric field strengths above 3 kV/cm the conductance suffers transient decreases that last <3 μs and are irregularly spaced in time. The average frequency of occurrence and magnitude of the transients increase rapidly with increasing field above the threshold. The conductance loss transients are accompanied by emission of light. These phenomena may be related to that of semiconductor laser emission.

scholarly journals On the Relationship between Circulation Patterns, the Southern Annular Mode, and Rainfall Variability in Western Cape

2021 ◽  
Author(s):  
Chibuike Chiedozie Ibebuchi
Keyword(s):  
South Africa ◽  
High Probability ◽  
Climate Models ◽  
Rainfall Variability ◽  
Principal Component ◽  
Southern Annular Mode ◽  
Average Frequency ◽  
Frequency Of Occurrence ◽  
Western Cape ◽  
Annular Mode

This study investigates circulation types (CTs) in Africa, south of the equator, that are related to wet and dry conditions in Western Cape, the statistical relationship between the selected CTs and the Southern Annular Mode (SAM), and changes in the frequency of occurrence of the CTs related to the SAM under the ssp585 scenario. Obliquely rotated principal component analysis applied to sea level pressure was used to classify CTs in Africa, south of the equator. Three CTs were found to have a high probability to be associated with wet days in Western Cape, and four CTs were equally found to have a high probability to be associated with dry days in Western Cape. Generally, the dry/wet CTs feature the southward/northward track of the mid-latitude cyclone, adjacent to South Africa; anti-cyclonic/cyclonic relative vorticity, and poleward/equatorward track of westerlies, south of South Africa. One of the selected wet CTs is significantly related to variations of the SAM. Years with an above-average SAM index correlate with the below-average frequency of occurrence of the wet CT. The results suggest that through the dynamics of the CT, the SAM might control the rainfall variability of Western Cape. Under the ssp585 scenario, the analyzed climate models indicated a possibility in the decrease of the frequency of occurrence of the aforementioned wet CT associated with cyclonic activity at the mid-latitudes, and an increase in the frequency of occurrence of the CT associated with enhanced SLP in the mid-latitudes.

scholarly journals Storm surge prediction and frequency analysis for Andhra coast of India

MAUSAM ◽  
2021 ◽  
Vol 48 (4) ◽  
pp. 555-566
Author(s):  
Y.R. RAO ◽  
P. CHITTIBABU ◽  
S. K. DUBE ◽  
A. D. RAO ◽  
P. C. SINHA
Keyword(s):  
Andhra Pradesh ◽  
East Coast ◽  
Coastal Region ◽  
Storm Surges ◽  
Coastal Flooding ◽  
Frequency Of Occurrence ◽  
The Past ◽  
Inland Inundation ◽  
Cyclonic Storms ◽  
Made In

 Storm surges associated with severe cyclonic storms are common occurrences along the east coast of India. The coastal districts of Andhra Pradesh have experienced major surges in the past. Storm surges and the rains associated with cyclones are major causes for coastal flooding in this region. An attempt has been made, in this paper, to simulate surges along the Andhra coast that would have occurred due to severe cyclones during 1891-1996. Inland inundation due to surges is also estimated by using an empirical formula. The computed results are validated with the available observations. The comparison using post-storm survey reports, appears reasonably good to assert that the model is capable of predicting the peak surge amplitude and its location. Frequency of occurrence relationships is obtained for various zones along the coastal region for the purpose of risk analysis.      

scholarly journals Eccentric Dipole Coordinates

1963 ◽  
Vol 16 (3) ◽  
pp. 423 ◽  
Author(s):  
KD Cole
Keyword(s):  
Average Frequency ◽  
Frequency Of Occurrence ◽  
The Earth ◽  
Eccentric Dipole

Recently, Bond and Jacka (1962) sought to order the average frequency of occurrence of visible auroras in eccentric dipole latitude. It is considered that eccentric dipole co-latitudes (q''), longitudes (f'), and times for places on the surface of the Earth (here assumed spherical) may be of interest to workers in various fields. Mapped grids of q'' and f' are reproduced here.

scholarly journals EFFECTS OF A CONTINUOUS LOW-LEVEL NO. 2 FUEL DISPERSION ON LABORATORY-HELD INTERTIDAL COLONIES

1977 ◽  
Vol 1977 (1) ◽  
pp. 557-561 ◽  
Author(s):  
J. R. Vanderhorst ◽  
R. M. Bean ◽  
L. J. Moore ◽  
P. Wilkinson ◽  
C.I. Gibson ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Species Diversity ◽  
Relative Abundance ◽  
Fuel Oil ◽  
Individual Species ◽  
Infrared Analysis ◽  
Frequency Of Occurrence ◽  
Contaminant Monitoring ◽  
Colonization Time ◽  
Occurrence Patterns

ABSTRACT Marine intertidal colonies on concrete substrates were exposed for six months to 0.1 and 0.6 mg/l No. 2 fuel oil (API Ref. Oil III, 38% aromatics). A continuous supply of the fuel oil dispersion was prepared by a mixing-separation apparatus, and nonfloating material was used as the contaminant. Monitoring of No. 2 fuel was by IR analysis of CCl4 extracts. Supplementary analyses were performed by gas chromatography, helium partitioning gas chromatography, and mass spectrometry. Colonies were obtained by stratified random sampling from an initial 500 field-colonized bricks. Field colonization time was nine months. Replicates of treatment concentrations and controls were studied under constant continuous photoperiod. Initial colonies consisted of approximately 83 species of intertidal plants and animals. Effects were measured by comparison of species diversity, relative abundance, numbers of species, and individual frequency of occurrence patterns. Species diversity was significantly lower in treated versus control colonies as was the total number of species. Relative abundance was not significantly affected. Individual species frequency of occurrence was significantly reduced in treated colonies; this was especially so for amphipods and decapods. Significant differences were not revealed for any biological parameter between the two treatment concentrations, although data from infrared analysis indicated the two concentrations were, in fact, different.

scholarly journals Female meiotic drive preferentially segregates derived metacentric chromosomes in Drosophila

2019 ◽  
Author(s):  
Nicholas B. Stewart ◽  
Yasir H. Ahmed-Braimah ◽  
Daniel G. Cerne ◽  
Bryant F. McAllister
Keyword(s):  
Chromosome Segregation ◽  
Meiotic Drive ◽  
Average Frequency ◽  
Mendelian Segregation ◽  
Closely Related Species ◽  
Chromosomal Inversions ◽  
Ideal System ◽  
Inversion Status ◽  
Paracentric Inversions

AbstractA vast diversity of karyotypes exists within and between species, yet the mechanisms that shape this diversity are poorly understood. Here we investigate the role of biased meiotic segregation—i.e., meiotic drive—in karyotype evolution. The closely related species, Drosophila americana and D. novamexicana, provide an ideal system to investigate mechanisms of karyotypic diversification. Since their recent divergence, D. americana has evolved two centromeric fusions: one between the 2nd and 3rd chromosomes, and another between the X and 4th chromosomes. The 2-3 fusion is fixed in D. americana, but the X-4 fusion is polymorphic and varies in frequency along a latitudinal cline. Here we evaluate the hypothesis that these derived metacentric chromosomes segregate preferentially to the egg nucleus during female meiosis in D. americana. Using two different methods, we show that the fused X-4 chromosome is transmitted at an average frequency of ~57%, exceeding expectations of 50:50 Mendelian segregation. Three paracentric inversions are found in the vicinity of the X-4 fusion and could potentially influence chromosome segregation. Using crosses between lines with differing inversion arrangements, we show that the transmission bias persists regardless of inversion status. Transmission rates are also biased in D. americana/D. novamexicana hybrid females, favoring both the X-4 and 2-3 fused arrangements over their unfused homologs. Our results show that meiotic drive influences chromosome segregation in D. americana favoring derived arrangements in its reorganized karyotype. Moreover, the fused centromeres are the facilitators of biased segregation rather than associated chromosomal inversions.

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