scholarly journals Dynamic microhabitat shifts in space and time of caddisfly larvae (Insecta: Trichoptera) in a first‐order calcareous mountain stream

Biologia ◽  
2021 ◽  
Author(s):  
Jan Martini ◽  
Johann Waringer
Keyword(s):  
Cluster Analysis ◽  
Grain Size ◽  
Mountain Stream ◽  
Feeding Guilds ◽  
Revealed Preferences ◽  
Feeding Types ◽  
First Order ◽  
Space And Time ◽  
Caddisfly Larvae ◽  
Microhabitat Preferences

AbstractBy studying substrate (choriotope) preferences of 25 caddisfly taxa in the Schreierbach stream, a calcareous, first order tributary of the Ybbs river (Lower Austria), we aimed on (1) detecting microhabitat preferences in space and time, (2) to relate this information with ontogenetic choriotope shifts, and (3) to explore relationships between feeding guilds and choriotopes chosen. For this, we took six sets of bi-monthly multi-habitat samples of larvae at three stream sections (360 samples). Densities were highest in Drusinae juveniles (53.60 %), Micrasema morosum (15.14 %), Drusus discolor (13.31 %) and D. monticola (4.46 %), and were significantly higher in the upper stream section (1900 ± 1039 larvae m− 2) than in the central (205 ± 23) and lower (141 ± 22). Ivlev electivity indices revealed preferences for Macrolithal in Rhyacophila spp. and Tinodes dives, for Microlithal in Drusinae juveniles, for Megalithal and Phytal in filtering Drusinae and Micrasema, and for Xylal and Akal in Limnephilinae. A cluster analysis of choriotope electivity yielded five clusters, corresponding with functional feeding types. At the instar level, the chosen grain size increased with increasing instar in some species. Observed habitat shifts in space and time reflected the interaction of instar-specific choriotope choice and longitudinal translocations.

A formal theory of objects, space and time

1990 ◽  
Vol 55 (1) ◽  
pp. 74-89 ◽  
Author(s):  
Wayne D. Blizard
Keyword(s):  
Formal Theory ◽  
Order Theory ◽  
First Order ◽  
Space And Time ◽  
First Order Theory ◽  
Logical Nature

The two statements “Two different objects cannot occupy the same place at the same time” and “An object cannot be in two different places at the same time” are axioms of our everyday understanding of objects, space and time. We develop a first-order theory OST (Objects, Space and Time) in which formal equivalents of these two statements are taken as axioms. Using the theory OST, we uncover other fundamental principles of objects, space and time. We attempt to understand the logical nature of these principles, to investigate their formal consequences, and to identify logical alternatives to them. For easy reference, all of the nonlogical axioms of OST are listed together at the end of §2. In §3, we introduce two possible extensions of OST.

Environmental effects on the structure of polychaete feeding guilds on the beaches of Sepetiba Bay, south-eastern Brazil

2012 ◽  
Vol 93 (4) ◽  
pp. 973-980 ◽  
Author(s):  
Gustavo Mattos ◽  
Ricardo S. Cardoso ◽  
André Souza Dos Santos
Keyword(s):  
Grain Size ◽  
Sandy Beach ◽  
Sandy Beaches ◽  
Feeding Guilds ◽  
Feeding Guild ◽  
Beach Sediment ◽  
Sepetiba Bay ◽  
Importance Index ◽  
Eastern Brazil ◽  
Macrofauna Communities

Several studies have been conducted to explain patterns of the abundance, richness and diversity of sandy-beach macrofauna; however, such analyses have ignored the overall functional structure of macrofauna communities. Few studies have examined polychaete feeding guilds on sandy beach environments. To examine the effects of environmental factors on polychaete feeding guilds on sandy beaches, 12 sandy beaches from five islands in Sepetiba Bay were sampled. A total of 24 polychaete morphospecies, grouped among 21 families, were identified in these sandy beaches. The polychaete species were classified into 10 feeding guilds, and the SDT guild (suspended-deposit feeders, discretely motile, with tentacles) was the most abundant feeding guild, with 34.2% of total number of organisms. The highest trophic importance index and index of trophic diversity values were recorded on the sheltered beaches. A canonical correspondence analysis showed that the exposure rate, beach length, and grain size of the beach sediment significantly affected the polychaete feeding guild distribution and abundance. We can conclude that sheltered beaches have a higher diversity of feeding guilds than exposed beaches and that the biological descriptors of the feeding guilds are directly associated with the grain size of the sediment.

scholarly journals Palynology of the Genus Stachytarpheta Vahl. (Verbenaceae)

2010 ◽  
Vol 2 (4) ◽  
pp. 27-33
Author(s):  
Olubukola ADEDEJI
Keyword(s):  
Cluster Analysis ◽  
Grain Size ◽  
Evolutionary History ◽  
Pollen Grains ◽  
Pollen Grain ◽  
The Other ◽  
Pollen Grain Size ◽  
Pollen Diameter ◽  
Stachytarpheta Cayennensis ◽  
Exine Morphology

The exine morphology of pollen grains of Stachytarpheta indica (Linn.) Vahl, Stachytarpheta cayennensis (Rich.) Vahl and Stachytarpheta angustifolia (Mill.) Vahl is reported. This study was carried out with a light microscope. Pollen grains from fresh anthers were collected and aceolysed. Statistical analysis used to analyse the data collected include cluster analysis, correlation analysis, similarity and distance indices. The pollen grains are spheroidal to oblate to sub-oblate in shape. They are aperturate, both colpate and porate. Tricolpate types occur most frequently, acolpate, monocolpate, bicolpate and tetracolpate types less frequently. The multicolpate and multiporate attributes in all the species indicate that the genus is not primitive in evolutionary history and this species probably, evolved around in the same time. According to the size, the pollen grains of the genus falls into groups permagna (pollen diameter 100-200 μm) and giganta (pollen diameter greater than 200 μm). S. cayennensis and S. anguistifolia belong to group permagna and S. indica only in the group giganta. This separates S. indica from the other two species. The large pollen grain size in the genus clearly supports the fact that the flowers in the genus are more insect-and-bird pollinated than wind pollinated. The similarity and distance indices of the species showed that S. cayennensis and S. angustifolia are the closest. S. indica is closer to S. angustifolia but farther from S. cayennensis.

Life histories, production, and microdistribution of two caddisflies (Trichoptera) in a Rocky Mountain stream

1986 ◽  
Vol 64 (12) ◽  
pp. 2706-2716 ◽  
Author(s):  
Gael A. Ogilvie ◽  
Hugh F. Clifford
Keyword(s):  
Life Histories ◽  
Larval Instar ◽  
Rocky Mountain ◽  
Annual Production ◽  
Mountain Stream ◽  
Prepupal Stage ◽  
First Order ◽  
Fine Particulate ◽  
Southern Alberta ◽  
Two Populations

This paper reports results of a 2-year study of the caddisflies Oligophlebodes zelti (Limnephilidae) and Neothremma alicia (Uenoidae) in a first-order Rocky Mountain stream of southern Alberta. The Oligophlebodes population had a univoltine cycle: eggs were oviposited in July and August and hatched in about 20 days, and the larvae grew rapidly during the remainder of the ice-free season. Larvae overwintered in the fourth larval instar and molted to the fifth instar the following spring. Pupation occurred in June, and adults started emerging in mid-July. Annual production for the O. zelti population was 116 mg∙m−2∙year−1. The Neothremma population had a 2-year cycle. Eggs apparently hatched after freeze-up. Larvae overwintered in the second instar. Most of the population achieved the third instar by the following July and the fourth instar by August, and spent the second winter in either the fourth or fifth instar. There was about a 3-week prepupal stage the following July and then emergence in July and August. Annual production for the N. alicia population was 103 mg∙m−2∙year−1. Oligophlebodes zelti and N. alicia larvae fed mainly on fine particulate organic matter and diatoms. Both O. zelti and N. alicia larvae were found on rocks only in fast water areas, but the two populations did not inhabit the same riffles. The riffles inhabited by O. zelti were wider with lower slopes and water velocities than riffles dominated by N. alicia larvae. Correlation analysis, using several parameters, indicated that total periphyton of the rocks might be a major factor accounting for O. zelti's distribution. The microdistribution of the N. alicia population was not correlated with any food source.

scholarly journals Analysis of the Clonal Relationship of Serotype O26:H11 Enterohemorrhagic Escherichia coli Isolates from Cattle

2009 ◽  
Vol 75 (21) ◽  
pp. 6947-6953 ◽  
Author(s):  
Lutz Geue ◽  
Sabrina Klare ◽  
Christina Schnick ◽  
Birgit Mintel ◽  
Katharina Meyer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cluster Analysis ◽  
Human Infection ◽  
Enterohemorrhagic Escherichia Coli ◽  
Clonal Relationship ◽  
Space And Time ◽  
Virulence Markers ◽  
Relationship Of ◽  
Cattle Farms

ABSTRACT Twelve cluster groups of Escherichia coli O26 isolates found in three cattle farms were monitored in space and time. Cluster analysis suggests that only some O26:H11 strains had the potential for long-term persistence in hosts and farms. As judged by their virulence markers, bovine enterohemorrhagic O26:H11 isolates may represent a considerable risk for human infection.

scholarly journals Recognition of Environmentally Vulnerable Depositional Facies in the Chacahua Lagoon, Oaxaca, Mexico

2005 ◽  
Vol 32 (2) ◽  
pp. 17 ◽  
Author(s):  
FELIPE RÍOS ◽  
GELIA SANDOVAL ◽  
ALFREDO FRÍAS
Keyword(s):  
Cluster Analysis ◽  
Grain Size ◽  
Organic Matter ◽  
Bottom Sediment ◽  
Environmental Conditions ◽  
Environmental Concern ◽  
Environmental Indicators ◽  
Depositional Facies ◽  
Sediment Samples ◽  
Insight Into

Over the years, human activity and environmental problems have impacted the Chacahua Lagoon in the State of Oaxaca, Mexico. In an attempt to gain more insight into the current environmental conditions of this lagoon, twenty-eight bottom sediment samples were collected in August 2003. Using depth, physical properties (grain-size and texture) and biological characteristics (organic matter and CaCO3 contents) of sediments as environmental indicators, three depositional facies were identified implementing cluster analysis, each facies seems to be under the influence of different processes. In terms of environmental concern, it was determined that the central part of the lagoon presents a high potential of pollutant sorption, thus this sector should be closely monitored.

scholarly journals First-order perturbations of Gödel-type metrics in non-dynamical Chern-Simons modified gravity

2021 ◽  
Author(s):  
Brett D Altschul ◽  
J Roberto S Nascimento ◽  
A Yu Petrov ◽  
P. J. Porfı́rio
Keyword(s):  
Analytical Solutions ◽  
Effective Potential ◽  
Modified Gravity ◽  
Perturbation Parameter ◽  
Field Equations ◽  
Schwarzschild Metric ◽  
First Order ◽  
Space And Time ◽  
Massive Particles ◽  
Chern Simons

Abstract G\"{o}del-type metrics that are homogeneous in both space and time remain, like the Schwarzschild metric, consistent within Chern-Simons modified gravity; this is true in both the non-dynamical and dynamical frameworks, each of which involves an additional pseudoscalar field coupled to the Pontryagin density. In this paper, we consider stationary first-order perturbations to these metrics in the non-dynamical framework. Under certain assumptions we find analytical solutions to the perturbed field equations. The solutions of the first-order field equations break the translational and cylindrical symmetries of the unperturbed metrics. The effective potential controlling planar geodesic orbits is also affected by the perturbation parameter, which changes the equilibrium radii for the orbits of both massive particles and massless photons.

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