Benthic Fauna Colonization of a New Reservoir with Particular Reference to the Chironomidae

1970 ◽  
Vol 27 (2) ◽  
pp. 213-232 ◽  
Author(s):  
C. G. Paterson ◽  
C. H. Fernando
Keyword(s):  
Dominant Species ◽  
Dominance Hierarchy ◽  
Benthic Fauna ◽  
Partial Loss ◽  
Organic Debris ◽  
Wide Range ◽  
The Rich ◽  
Laurel Creek ◽  
Chironomid Fauna ◽  
New Reservoir

At the time of first filling of Laurel Creek Reservoir in the spring of 1967 the benthic fauna consisted of submerged terrestrial organisms and obligate and facultative rheophilic species. Two months after initial filling substantial populations of colonizing limnophilic species developed in the habitat whereas the terrestrial and obligate rheophilic components were lost. By the 4th month the fauna was dominated by euryoxybiontic limnophiles and by facultative species. In the period immediately prior to reservoir drainage in the autumn of 1967 the population densities of the euryoxybiontic chironomids declined whereas polyoxybiontic species continued to increase in abundance. These changes in the dominance hierarchy of the chironomid fauna were associated with the partial loss of the rich deposits of organic debris by siltation and decomposition. Survival of winter drainage of the reservoir by many limnophilic species produced an appreciably different pattern of colonization when the reservoir refilled in 1968. During the second summer of the reservoir's existence most euryoxybiontic chironomids further declined in abundance and were replaced by polyoxybiontic forms as the dominant species. The facultative species originally derived from the creek fauna are adapted to a wide range of environmental conditions and the modifications of the reservoir habitat with time had little effect on their abundance.

The effect of winter drainage on reservoir benthic fauna

1969 ◽  
Vol 47 (4) ◽  
pp. 589-595 ◽  
Author(s):  
C. G. Paterson ◽  
C. H. Fernando
Keyword(s):  
Indirect Evidence ◽  
Benthic Fauna ◽  
Atmospheric Conditions ◽  
Southern Ontario ◽  
Probability Of Survival ◽  
Short Period ◽  
Benthic Environment ◽  
Laurel Creek ◽  
Caddis Fly ◽  
Chironomid Fauna

Winter drainage of Laurel Creek Reservoir in southern Ontario exposed the benthic environment to atmospheric conditions for between 168 and 176 days. During the first 50 days, which had above-freezing temperatures, much of the fauna was destroyed. In the next 100 days the substrate became frozen to depths greater than 20 cm. Freezing of the substrate resulted in the loss of the oligochaetes, nematodes, and oribatoid mites as well as a large percentage of the chironomid fauna. Small numbers of the caddis fly, Agraylea multipunctata; the chironomid Cricotopus trifasciatus; and the molluscs Planorbula jenksii and Lymnaea palustris were found to survive the period of freezing and the subsequent short period of thawing before the refilling of the reservoir. Indirect evidence suggests the survival of small numbers of certain species of chironomids not found in the samples. Glyplotendipes barbipes showed the highest survival under the conditions of exposure, as the population immediately after refilling was between 12.5 and 46.4% of that found before drainage of the reservoir. The fauna did not actively move deeper into the substrate as freezing progressed although the probability of survival was greater at the deeper levels. A. multipunctata, C. trifasciatus, and G. barbipes have been found able to pupate and emerge after survival in the exposed substrate.

An ecological study of the branchiobdellid commensals (Annelida-Branchiobdellidae) of some mid-western Ontario crayfish

1968 ◽  
Vol 46 (5) ◽  
pp. 835-843 ◽  
Author(s):  
John E. Bishop
Keyword(s):  
Host Specificity ◽  
Dominant Species ◽  
Ecological Study ◽  
Rabbit Serum ◽  
First Year ◽  
Serological Testing ◽  
Severe Winter ◽  
Orconectes Propinquus ◽  
Winter Conditions ◽  
Laurel Creek

Orconectes propinquus and Cambarus robustus from the Speed River, Sunfish Lake, and Laurel Creek, harbor two branchiobdellids, Cambarincola chirocephala and Pterodrilus distichus. Both adult and cocoon populations of the dominant species (C. chirocephala) are proportional to the size of the host throughout the year, except that first-year crayfish are free of cocoons. The reduction in total number of commensals from autumn to spring can be attributed to severe winter conditions. A subrostral site of preference for adult branchiobdellid attachment, and a dominant abdomen I and II site for cocoon deposition are indicated for O. propinquus. On C. robustus, adults are most commonly found on the antennal bases and among the maxillipeds, and cocoons on the last live abdominal sternites. No host specificity is evident although an unidentified Cambarus sp. from Sunfish Lake is free of commensals. Host incompatibility may explain this, but data from Laurel Creek indicate that silting of the microhabitat is responsible for loss of branchiobdellid population. The crayfish–branchiobdellid relationship is commensal, or at most facultatively parasitic, as adult worms can live without a host for extended periods. Serological testing of rabbit serum containing branchiobdellid antibodies against crayfish serum is negative. The dependence of the egg stage on the host for some undetermined factor or factors is discussed. An Asellus sp. fails to pick up the commensals even when exposed under ideal conditions for colonization.

scholarly journals Immigration and economic mobility

2021 ◽  
Author(s):  
Maria F. Hoen ◽  
Simen Markussen ◽  
Knut Røed
Keyword(s):  
Labor Market ◽  
Low Income ◽  
Labor Market Outcomes ◽  
Lower Class ◽  
Low Income Countries ◽  
Market Outcomes ◽  
Wide Range ◽  
Class Background ◽  
The Rich ◽  
Relative Prime

AbstractWe examine how immigration affects natives’ relative prime-age labor market outcomes by economic class background, with class background established on the basis of parents’ earnings rank. Exploiting alternative sources of variation in immigration patterns across time and space, we find that immigration from low-income countries reduces intergenerational mobility and thus steepens the social gradient in natives’ labor market outcomes, whereas immigration from high-income countries levels it. These findings are robust with respect to a wide range of identifying assumptions. The analysis is based on high-quality population-wide administrative data from Norway, which is one of the rich-world countries with the most rapid rise in the immigrant population share over the past two decades. Our findings suggest that immigration can explain a considerable part of the observed relative decline in economic performance among natives with a lower-class background.

scholarly journals Fixel-based Analysis of Diffusion MRI: Methods, Applications, Challenges and Opportunities

2020 ◽  
Author(s):  
Thijs Dhollander ◽  
Adam Clemente ◽  
Mervyn Singh ◽  
Frederique Boonstra ◽  
Oren Civier ◽  
...  
Keyword(s):  
Diffusion Mri ◽  
State Of The Art ◽  
Specific Information ◽  
Analysis Framework ◽  
Wide Range ◽  
Challenges And Opportunities ◽  
P Diffusion ◽  
Modelling Techniques ◽  
The Rich

Diffusion MRI has provided the neuroimaging community with a powerful tool to acquire in-vivo data sensitive to microstructural features of white matter, up to 3 orders of magnitude smaller than typical voxel sizes. The key to extracting such valuable information lies in complex modelling techniques, which form the link between the rich diffusion MRI data and various metrics related to the microstructural organisation. Over time, increasingly advanced techniques have been developed, up to the point where some diffusion MRI models can now provide access to properties specific to individual fibre populations in each voxel in the presence of multiple "crossing" fibre pathways. While highly valuable, such fibre-specific information poses unique challenges for typical image processing pipelines and statistical analysis. In this work, we review the "fixel-based analysis" (FBA) framework that implements bespoke solutions to this end, and has recently seen a stark increase in adoption for studies of both typical (healthy) populations as well as a wide range of clinical populations. We describe the main concepts related to fixel-based analyses, as well as the methods and specific steps involved in a state-of-the-art FBA pipeline, with a focus on providing researchers with practical advice on how to interpret results. We also include an overview of the scope of current fixel-based analysis studies (until August 2020), categorised across a broad range of neuroscientific domains, listing key design choices and summarising their main results and conclusions. Finally, we critically discuss several aspects and challenges involved with the fixel-based analysis framework, and outline some directions and future opportunities.

scholarly journals THE LAND BEHIND THE LAND BEHIND BAGHDAD: ARCHAEOLOGICAL LANDSCAPES OF THE UPPER DIYALA (SIRWAN) RIVER VALLEY

Iraq ◽  
2017 ◽  
Vol 79 ◽  
pp. 47-69 ◽  
Author(s):  
Jesse Casana ◽  
Claudia Glatz
Keyword(s):  
Bronze Age ◽  
Physical Geography ◽  
River Valley ◽  
Archaeological Sites ◽  
Archaeological Survey ◽  
Near Eastern ◽  
The North ◽  
Wide Range ◽  
Regional Project ◽  
The Rich

While the Diyala (Kurdish Sirwan) River Valley is storied in Near Eastern archaeology as home to the Oriental Institute's excavations in the 1930s as well as to Robert McC. Adams’ pioneering archaeological survey, The Land Behind Baghdad, the upper reaches of the river valley remain almost unknown to modern scholarship. Yet this region, at the interface between irrigated lowland Mesopotamia and the Zagros highlands to the north and east, has long been hypothesized as central to the origins and development of complex societies. It was hotly contested by Bronze Age imperial powers, and offered one of the principle access routes connecting Mespotamia to the Iranian Plateau and beyond. This paper presents an interim report of the Sirwan Regional Project, a regional archaeological survey undertaken from 2013–2015 in a 4000 square kilometre area between the modern city of Darbandikhan and the plains south of Kalar. Encompassing a wide range of environments, from the rugged uplands of the Zagros front ranges to the rich irrigated basins of the Middle Diyala, the project has already discovered a wealth of previously unknown archaeological sites ranging in date from the Pre-Pottery Neolithic through the modern period. Following an overview of the physical geography of the Upper Diyala/Sirwan, this paper highlights key findings that are beginning to transform our understanding of this historically important but poorly known region.

scholarly journals Objective sensory testing methods reveal a higher prevalence of olfactory loss in COVID-19–positive patients compared to subjective methods: A systematic review and meta-analysis

2020 ◽  
Author(s):  
Mackenzie E Hannum ◽  
Vicente A Ramirez ◽  
Sarah J Lipson ◽  
Riley D Herriman ◽  
Aurora K Toskala ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Objective Measures ◽  
Subjective Measures ◽  
Partial Loss ◽  
Olfactory Loss ◽  
Point Estimates ◽  
Pooled Prevalence ◽  
Wide Range ◽  
Subjective Measurements ◽  
Smell Loss

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has currently infected over 6.5 million people worldwide. In response to the pandemic, numerous studies have tried to identify causes and symptoms of the disease. Emerging evidence supports recently acquired anosmia (complete loss of smell) and hyposmia (partial loss of smell) as symptoms of COVID-19, but studies of olfactory dysfunction show a wide range of prevalence, from 5% to 98%. We undertook a search of Pubmed/Medline and Google Scholar with the keywords “COVID-19,” “smell,” and/or “olfaction.” We included any study that quantified smell loss (anosmia and hyposmia) as a symptom of COVID-19. Studies were grouped and compared based on the type of method used to measure smell loss—subjective measures such as self-reported smell loss versus objective measures using rated stimuli—to determine if prevalence differed by method type. For each study, 95% confidence intervals (CIs) were calculated from point estimates of olfactory disturbances. We identified 34 articles quantifying anosmia as a symptom of COVID-19 (6 objective, 28 subjective), collected from cases identified from January 16 to April 30, 2020. The pooled prevalence estimate of smell loss was 77% when assessed through objective measurements (95% CI of 61.4-89.2%) and 44% with subjective measurements (95% CI of 32.2-57.0%). Objective measures are a more sensitive method to identify smell loss as a result of infection with SARS-CoV-2; the use of subjective measures, while expedient during the early stages of the pandemic, underestimates the true prevalence of smell loss.

The Age-Old Tradition of Mexico's Popular Theatre

1989 ◽  
Vol 14 (2) ◽  
pp. 111-122 ◽  
Author(s):  
Donald H. Frischmann
Keyword(s):  
Broad Spectrum ◽  
Common People ◽  
Popular Theatre ◽  
Careful Observation ◽  
Wide Range ◽  
Rural Mexico ◽  
The Common ◽  
The Rich

Mexico's popular theatre is a multi-faceted ancient art whose roots extend deep into pre-Hispanic cultures, as well as into the popular dramatic tradition of Spain. Today, nearly five centuries after the arrival of the Spaniards, popular theatre continues to be a phenomenon both of urban and rural Mexico, reflecting the rich gamut of cultural and historical characteristics found throughout this vast geographic and ethnic patchwork. While a wide range of distinctive qualities exist across the broad spectrum of popular theatre, formal differences give way – through careful observation and analysis – to the perception of an underlying unity of purpose which supports all popular theatre: addressing the spiritual and material needs of the common people.

Study of a Rich/Lean Staged Combustion Concept for Hydrogen at Gas Turbine Relevant Conditions

2013 ◽  
Author(s):  
Felipe Bolaños ◽  
Dieter Winkler ◽  
Felipe Piringer ◽  
Timothy Griffin ◽  
Rolf Bombach ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Carbon Capture ◽  
Flame Temperature ◽  
Nox Emissions ◽  
Hydrogen Fuel ◽  
Auto Ignition ◽  
Wide Range ◽  
The Rich

The combustion of hydrogen-rich fuels (> 80 % vol. H2), relevant for gas turbine cycles with “pre-combustion” carbon capture, creates great challenges in the application of standard lean premix combustion technology. The significant higher flame speed and drastically reduced auto-ignition delay time of hydrogen compared to those of natural gas, which is normally burned in gas turbines, increase the risk of higher NOX emissions and material damage due to flashback. Combustion concepts for gas turbines operating on hydrogen fuel need to be adapted to assure safe and low-emission combustion. A rich/lean (R/L) combustion concept with integrated heat transfer that addresses the challenges of hydrogen combustion has been investigated. A sub-scale, staged burner with full optical access has been designed and tested at gas turbine relevant conditions (flame temperature of 1750 K, preheat temperature of 400 °C and a pressure of 8 bar). Results of the burner tests have confirmed the capability of the rich/lean staged concept to reduce the NOx emissions for undiluted hydrogen fuel. The NOx emissions were reduced from 165 ppm measured without staging (fuel pre-conversion) to 23 ppm for an R/L design having a fuel-rich hydrogen pre-conversion of 50 % at a constant power of 8.7 kW. In the realized R/L concept the products of the first rich stage, which is ignited by a Pt/Pd catalyst (under a laminar flow, Re ≈ 1900) are combusted in a diffusion-flame-like lean stage (turbulent flow Re ≈ 18500) without any flashback risk. The optical accessibility of the reactor has allowed insight into the combustion processes of both stages. Applying OH-LIF and OH*-chemiluminescence optical techniques, it was shown that mainly homogeneous reactions at rich conditions take place in the first stage, questioning the importance of a catalyst in the system, and opening a wide range of optimization possibilities. The promising results obtained in this study suggest that such a rich/lean staged burner with integrated heat transfer could help to develop a new generation of gas turbine burners for safe and clean combustion of H2-rich fuels.

scholarly journals The Association of Religion Data Archives (ARDA): Online Research Data, Tools and References

2008 ◽  
Vol 1 (3) ◽  
pp. 456-470 ◽  
Author(s):  
Roger Finke ◽  
Amy Adamczyk
Keyword(s):  
State University ◽  
Pennsylvania State University ◽  
Research And Teaching ◽  
Data Archives ◽  
Wide Range ◽  
International Data ◽  
Data Files ◽  
The Rich ◽  
Rich Data ◽  
Website Features

AbstractThe Association of Religion Data Archives (ARDA) currently archives over 500 local, national, and international data files, and offers a wide range of research tools to build surveys, preview data online, develop customized maps and reports of United States church membership, and examine religion differences across nations and regions of the world. The ARDA also supports reference and teaching tools that draw on the rich data archive. This research article offers a brief introduction to the quantitative data available for exploration or download, and a few of the website features most useful for research and teaching. Supported by the Lilly Endowment, the John Templeton Foundation, the Pennsylvania State University, and the Baylor Institute for Studies of Religion, all data downloads and online services are free of charge.

Diet components in the food of Antarctic ascidians living at low levels of primary production

2004 ◽  
Vol 16 (2) ◽  
pp. 123-128 ◽  
Author(s):  
MARCOS TATIÁN ◽  
RICARDO SAHADE ◽  
GRACIELA B. ESNAL
Keyword(s):  
Primary Production ◽  
Stomach Contents ◽  
Food Sources ◽  
Potter Cove ◽  
Mean Values ◽  
Faecal Pellets ◽  
Wide Range ◽  
The Rich ◽  
Wind Mixing ◽  
The Antarctic

Coupling between pelagic and benthic systems has been described in numerous shallow water communities. In Potter Cove, where pelagic primary production is low (not only during the Antarctic winter but also during the summer), the rich benthic community present there must depend on other food sources than phytoplankton. Over a year-round period we determined the abundance of the different seston particles which constituted the stomach contents of the Antarctic ascidian Cnemidocarpa verrucosa (Lesson, 1830) at Potter Cove. Stomach repletion was highest in November and lowest in June. Ascidians took in a wide range of particles from large detritus (macroalgal debris and faecal pellets) to minute particles < 5 μm. Large detritus and minute particles together represent the main percentage of contents throughout the year (mean 91%). Diatoms were a low percentage (mean 4.5%). Unidentified flagellates, dinoflagellates and coccolithophorids were scarce, with mean values lower than 4%. Among diatoms benthic species were more abundant in summer and pelagic ones prevailed from March to November. Resuspension of benthic material due to wind mixing and the input of allochthonous particles by currents are important mechanisms that ensure food for ascidians and the community of suspension feeders in Potter Cove.

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