Studies on the spatial heterogeneity of shallow water benthos with particular reference to the Chironomidae

1971 ◽  
Vol 49 (7) ◽  
pp. 1013-1019 ◽  
Author(s):  
C. G. Paterson ◽  
C. H. Fernando
Keyword(s):  
Opposite Effect ◽  
Common Species ◽  
Distributional Pattern ◽  
Population Densities ◽  
Benthic Species ◽  
Experimental Examination ◽  
The Common ◽  
The Mean ◽  
Total Fauna ◽  
Behavioral Mechanisms

The examination of numbers of 6-in. Ekman grab samples from areas of 2 m2 or less in a variety of shallow lentic habitats revealed heterogeneity in the spatial distribution of most species of macrobenthos in each habitat. Chironomus abortivus Malloch, Glyptotendipes barbipes (Staeger), Procladius freemani Sublette, and the Oligochaeta were invariably aggregated when their population densities were adequate to determine a distributional pattern. The Chironomidae, considered as a group, also displayed an aggregated distribution in all habitats. Other benthic species had distributional patterns that varied from random to highly aggregated in the different habitats. No evidence was found that any species are normally randomly distributed. Analyses of mean crowding of the common species in each habitat suggest that the species often respond independently to microenvironmental variations. The factors which produce well-defined aggregations of one species may be neutral, or they may have the opposite effect on the distribution of other species. Experimental examination of the possible occurrence of behavioral mechanisms of aggregation in the two chironomids, Chironomus attenuatus Walker and Glyptotendipes barbipes, revealed that they lend to aggregate at low population densities (≈ 1/10 cm2) but are randomly distributed in a uniform environment when present in higher densities. Because of the aggregated nature of most benthic species four 6-in. Ekman grab samples were usually required to obtain a population estimate of the total fauna, total chironomid fauna, and the dominant species within ± 30% of the mean obtained with a larger number of samples.

Factors affecting distribution and abundance of small demersal fishes in the Gulf of Carpentaria, Australia

1995 ◽  
Vol 46 (6) ◽  
pp. 909 ◽  
Author(s):  
TJ Martin ◽  
DT Brewer ◽  
SJM Blaber
Keyword(s):  
Community Composition ◽  
Fish Community ◽  
Common Species ◽  
Small Species ◽  
Benthic Species ◽  
Factors Affecting ◽  
Fish Community Composition ◽  
The Common ◽  
The Relationship ◽  
Demersal Fishes

The distribution and abundance of small demersal fishes at depths of 7 to 63 m in the Gulf of Carpentaria were surveyed at 103 stations in 1990 and 60 stations in 1991 with the aid of a Church dredge. A total of 234 species from 70 families was recorded. The most abundant fish groups were cryptic or benthic species such as pleuronectiforms, scorpaenids, apogonids, platycephalids, monacanthids and gobiids. Several species, such as Elates ransonnetti, Pseudorhombus elevatus and Suggrundus macracanthus, are widely distributed; others had a narrower distribution. Apogon poecilopterus, Apogon fasciatus, Arnoglossus waitei and Uranoscopus cognatus were most abundant in the northern Gulf of Carpentaria and Cynoglossus macrophthalmus, Dactyloptena papilio and Paramonacanthus japonicus in the eastern gulf. The dredge is more efficient at catching smaller fish: the smallest individuals of 113 species were caught by the dredge and a further 32 small species were caught only by the dredge. The effects of depth, substratum type and turbidity on the abundance of 17 common species at different stations are described. Neither temperature nor salinity showed significant correlations with catches of the common species. There were significant correlations between the presence of structured benthos and both the number of fish species and the number of fish individuals. The relationship between benthic structure and fish is discussed in relation to the possible effects of trawling, and it is postulated that changes to structure resulting from trawling may affect fish community composition.

scholarly journals Application of COI Primers 30F/885R in Rotifers to Regional Species Diversity in (Sub)Tropical China

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 390
Author(s):  
Ya-Nan Zhang ◽  
Shao-Lin Xu ◽  
Qi Huang ◽  
Ping Liu ◽  
Bo-Ping Han
Keyword(s):  
Species Diversity ◽  
Genetic Distance ◽  
Common Species ◽  
Large River ◽  
Coi Gene ◽  
Keratella Cochlearis ◽  
The Common ◽  
The Mean ◽  
Coi Sequences ◽  
Tropical China

Rotifers are the most diverse group in freshwater zooplankton and play an important role in food webs and ecosystems. DNA barcoding has become a useful approach to investigate species diversity at local and regional scales, but its application is still limited by efficient primers for the group. To test a pair of primers 30F/885R recently designed for rotifers, we applied them to investigating regional species diversity in the freshwater of South China. We sequenced the cytochrome c oxidase subunit I (COI) gene of rotifers collected from the investigated 23 reservoirs in a large river basin and obtained 145 COI sequences from 33 species in 14 genera. The mean PCR success rate for all tested species was 50%. The 145 sequenced mtCOI in this study covered 33 of 64 identified morphological taxa, including most of the common species in the basin. The intraspecific genetic distance was calculated with a K2P model for 24 rotifer species occurring in the quantitative samples, in which 15 rotifers, such as Keratella cochlearis and Brachionus calyciflorus, had a genetic distance higher than 5%. The high intraspecific genetic differentiation indicates that cryptic species are probably common in (sub)tropical China.

A revised method for estimating population densities of common wombats (Vombatus ursinus)

2012 ◽  
Vol 34 (2) ◽  
pp. 170
Author(s):  
John McIlroy ◽  
John Collins ◽  
Philip Borchard
Keyword(s):  
Population Density ◽  
Regression Equations ◽  
Population Densities ◽  
Common Wombat ◽  
The Common ◽  
The Mean

Estimation of the population density of the common wombat (Vombatus ursinus) has used regression equations based on the mean number of burrows used per 24 h over five successive 24-h periods. While adequate, the method has several deficiencies and required 6 successive days of fieldwork to carry out. We describe a revised method based on considerably more data. It provides more precise estimates, can be used for greater numbers of used burrows and can be carried out over a much shorter period.

Comparison of Heffner Criteria and Light Criteria in Differentiating Exudative and Transudative Pleural Effusion

2020 ◽  
Vol 22 (3) ◽  
pp. 141-145
Author(s):  
Krishna Chandra Devkota ◽  
S Hamal ◽  
PP Panta
Keyword(s):  
Pleural Effusion ◽  
Cross Sectional Study ◽  
Pleural Space ◽  
Sectional Study ◽  
Inclusion Criteria ◽  
Cross Sectional ◽  
Medical College ◽  
The Common ◽  
The Mean ◽  
Exudative Pleural Effusion

Pleural effusion is present when there is >15ml of fluid is accumulated in the pleural space. It can be divided into two types; exudative and transudative pleural effusion. Tuberculosis and parapneumonic effusion are the common cause of exudative pleural effusion whereas heart failure accounts for most of the cases of transudative pleural effusion. This study was a hospital based cross sectional study performed at Nepal Medical College during the period of January 2016-December 2016. A total of 50 patients who fulfilled the inclusion criteria were enrolled. Pleural effusion was confirmed by clinical examination and radiology. After confirmation of pleural effusion, pleural fluid was aspirated and was analysed for protein, LDH, cholesterol. The Heffner criteria was compared with Light criteria to classify exudative or transudative pleural effusion. Among 50 patients, 30 were male and 20 were female. The mean age of patient was 45.4±21.85 years. The sensitivity and specificity of using Light criteria to detect the two type of pleural effusion was 100% and 90.9%, whereas using Heffner criteria was 94.87%, 100% respectively(P<0.01). There are variety of causes for development of pleural effusion and no one criteria is definite to differentiate between exudative or transudative effusion. In this study Light criteria was more sensitive whereas Heffner criteria was more specific to classify exudative pleural effusion. Hence a combination of criteria might be useful in case where there is difficulty to identify the cause of pleural effusion.

Of Reformed Versifying

2018 ◽  
Author(s):  
Neil Rhodes
Keyword(s):  
Sixteenth Century ◽  
Faerie Queene ◽  
Classical Literature ◽  
Native Form ◽  
Christian Doctrine ◽  
English Verse ◽  
The Common ◽  
The Mean ◽  
The Faerie Queene ◽  
Stylistic Ideal

This chapter examines how the development of English poetry in the second half of the sixteenth century is characterized by the search for an appropriate style. In this context, ‘reformed versifying’ may be understood as a reconciliation of high and low in which the common is reconfigured as a stylistic ideal of the mean. That development can be traced in debates about prosody where an alternative sense of ‘reformed versifying’ as adapting classical metres to English verse is rejected in favour of native form. At the same time Sidney recuperates poetry by reforming it as an agent of virtue. Reformation and Renaissance finally come together in Spenser, who realizes Erasmus’ aim of harmonizing the values of classical literature with Christian doctrine, and reconciles the foreign and the ‘homewrought’. The Faerie Queene of 1590 represents the triumph of the mean in both style and, through its celebration of marriage, in substance.

scholarly journals Genetic gain in the breeding program of common beans at IAC from 1989 to 2007

2010 ◽  
Vol 10 (4) ◽  
pp. 329-336 ◽  
Author(s):  
Alisson Fernando Chiorato ◽  
Sérgio Augusto Morais Carbonell ◽  
Roland Vencovsky ◽  
Nelson da Silva Fonseca Júnior ◽  
José Baldin Pinheiro
Keyword(s):  
Grain Yield ◽  
Common Bean ◽  
Genetic Gain ◽  
Grain Quality ◽  
The State ◽  
Breeding Program ◽  
Common Beans ◽  
The Common ◽  
The Mean ◽  
Second Period

The goal of the present work was to evaluate the genetic gain obtained in grain yield for the common bean genotypes from 1989 until 2007, at the Instituto Agronômico de Campinas, in the state of São Paulo. Genetic gain has been separated into two research periods; the first, from 1989 to 1996, and the second, from 1997 to 2007. In the first period, a genetic gain of 1.07 % per year was obtained, whereas for the second period, the gain was zero. However, the mean yield of the evaluated lines was approximately 1000 kg ha-1 superior to the figures obtained in the first period. The main cause for the absence of genetic gain in the second period is that the focus of the breeding program was changed to grain quality. The individualized analysis of the genotypes with carioca grains in the second period indicated the lack of genetic gain during the investigated period.

Addressing common errors and misconceptions in integral calculus with clickers and classroom voting

2019 ◽  
Vol 39 (2) ◽  
pp. 71-85
Author(s):  
Kelly Cline ◽  
Holly Zullo ◽  
David A Huckaby
Keyword(s):  
Correct Answer ◽  
Group Discussion ◽  
Multiple Choice ◽  
Small Group Discussion ◽  
Multiple Choice Questions ◽  
Integral Calculus ◽  
Common Features ◽  
Incorrect Answer ◽  
The Common ◽  
The Mean

Abstract Common student errors and misconceptions can be addressed through the method of classroom voting, in which the instructor presents a multiple-choice question to the class, and after a few minutes for consideration and small-group discussion, each student votes on the correct answer, using a clicker or a phone. If a large number of students have voted for one particular incorrect answer, the instructor can recognize and address the issue. In order to identify multiple-choice questions that are especially effective at provoking common errors and misconceptions, we recorded the percentages of students voting for each option on each question used in 25 sections of integral calculus, taught by 7 instructors, at 4 institutions, over the course of 12 years, on a collection of 172 questions. We restricted our analysis to the 115 questions which were voted on by at least 5 different classes. We present the six questions that caused the largest percentages of students to vote for a particular incorrect answer, discuss how we used these questions in the classroom, and examine the common features of these questions. Further, we look for correlations between question characteristics and the mean percentage of students voting for common errors on these questions, and we find that questions based on general cases have higher percentages of students voting for common errors.

Marine tube-dwelling diatoms of eastern Canada: descriptions, checklist, and illustrated key

1984 ◽  
Vol 62 (4) ◽  
pp. 778-794 ◽  
Author(s):  
Christopher S. Lobban
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Common Species ◽  
Bay Of Fundy ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
The Common ◽  
Living Material ◽  
St Lawrence Estuary ◽  
A New Species

From a study of living materials and specimens in several regional herbaria, a list has been drawn up of all the common and several of the rarer tube-dwelling diatoms of eastern Canada. Descriptions, illustrations of living material and acid-cleaned valves, and a key to the species are provided. Most specimens were from the Atlantic Provinces and the St. Lawrence estuary, but a few were from the Northwest Territories. By far the most common species is Berkeleya rutilans. Other species occurring commonly in the Quoddy Region of the Bay of Fundy, and sporadically in space and time elsewhere, arc Navicula delognei (two forms), Nav. pseudocomoides, Nav. smithii, Haslea crucigera, and a new species, Nav.rusticensis. Navicula ramosissima and Nav. mollis in eastern Canada are usually found as scattered cohabitants in tubes of other species. Nitzschia tubicola and Nz. fontifuga also occur sporadically as cohabitants.

Utilization of heterologous siderophores and rhizosphere competence of fluorescent Pseudomonas spp.

1995 ◽  
Vol 41 (2) ◽  
pp. 126-135 ◽  
Author(s):  
Jos M. Raaijmakers ◽  
Lentse van der Sluis ◽  
Peter A. H. M. Bakker ◽  
Bob Schippers ◽  
Margot Koster ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Population Densities ◽  
Common Assumption ◽  
Fluorescent Pseudomonas ◽  
Siderophore Receptors ◽  
Rhizosphere Interactions ◽  
Rhizosphere Population ◽  
Rhizosphere Competence ◽  
The Common ◽  
Derivative Strain

In this study, the potential of different Pseudomonas strains to utilize heterologous siderophores was compared with their competitiveness in the rhizosphere of radish. This issue was investigated in interactions between Pseudomonas putida WCS358 and Pseudomonas fluoresceins WCS374 and in interactions between strain WCS358 and eight indigenous Pseudomonas strains capable of utilizing pseudobactin 358. During four successive plant growth cycles of radish, strain WCS358 significantly reduced rhizosphere population densities of the wild-type strain WCS374 by up to 30 times, whereas derivative strain WCS374(pMR), harboring the siderophore receptor PupA for ferric pseudobactin 358, maintained its population density. Studies involving interactions between strain WCS358 and eight different indigenous Pseudomonas strains demonstrated that despite the ability of these indigenous isolates to utilize pseudobactin 358, their rhizosphere population densities were significantly reduced by strain WCS358 by up to 20 times. Moreover, rhizosphere colonization by WCS358 was not affected by any of these indigenous strains, even though siderophore-mediated growth inhibition of WCS358 by a majority of these strains was demonstrated in a plate bioassay. In conclusion, it can be stated that siderophore-mediated competition for iron is a major determinant in interactions between WCS358 and WCS374 in the rhizosphere. Moreover, our findings support the common assumption that cloning of siderophore receptor genes from one Pseudomonas strain into another can confer a competitive advantage in interactions in the rhizosphere. Interactions between WCS358 and the selected indigenous rhizosphere isolates, however, indicate that other traits also contribute to the rhizosphere competence of fluorescent Pseudomonas spp.Key words: siderophore, siderophore receptors, root colonization, fluorescent Pseudomonas.

scholarly journals Distribution of twin kHz QPOs in LMXBs

2012 ◽  
Vol 8 (S290) ◽  
pp. 327-328
Author(s):  
D. H. Wang ◽  
L. Chen
Keyword(s):  
Common Property ◽  
Periodic Oscillation ◽  
Quasi Periodic Oscillation ◽  
Mean Values ◽  
Orbital Frequency ◽  
Low Mass ◽  
The Common ◽  
The Mean ◽  
X Ray Binaries ◽  
Z Sources

AbstractWith kilohertz quasi-periodic oscillation (kHz QPO) sources in neutron star low mass X-ray binaries (NS-LMXBs) published up to now, we analyze the centroid frequency (ν) distribution of twin kHz QPOs. We find that Atoll and Z sources show the similar distributions of ν1 and ν2, which indicate that twin kHz QPOs may be the common property of NS-LXMBs and have the similar physical origins. The mean values of ν1 and ν2 in Atoll sources are higher than those in Z sources, and we consider that this may because the QPO signals are sheltered by the thicken accretion disk or corona in Z sources. The maximums of ν2 in both Atoll and Z sources are the same order as the Keplerian orbital frequency of the NS surface, so kHz QPOs could occur near the NS surface.

Sign in / Sign up

Export Citation Format

Share Document