Ecology of Chironomidae (Diptera) in a Polar Lake

1976 ◽  
Vol 33 (2) ◽  
pp. 227-247 ◽  
Author(s):  
H. E. Welch
Keyword(s):  
Energy Flow ◽  
Growth Efficiency ◽  
Life Cycles ◽  
Egg Laying ◽  
Larval Life ◽  
Metabolic Compensation ◽  
Class Strength ◽  
Growth Respiration ◽  
Definition Of

The six common genera of Chironomidae (Diptera) in Char Lake, Resolute, Northwest Territories (74°42′N lat.) were studied intensively from 1969 to 1972. Heterotrissocladius oliveri and a Trissocladius species are characteristic of the sediment zone, while two species of Orthocladius, Pseudodiamesa arctica, Paracladius quadrinodosus, and Lauterbornia sp. are restricted mainly to the rocky and moss zones. Life cycles are 2 or 3 yr, depending upon the species. Year-classes could be discriminated by instar frequency distribution. Populations increased steadily during the study period, for an average increase in strength of 5 times between the 1968 and 1971 year-classes. Summer emergence and egg-laying conditions are of overriding importance to year-class strength. Mortality within year-classes is undetectable until the last 4 mo of larval life, when mortality due to char predation is about 65% between April and the time of emergence. The physiology of these chironomids does not seem unusual aside from continuing activity down to 0 C, and there is no indication of metabolic compensation. Net growth efficiency averages 36%. Assimilated energy (growth + respiration) at 8.6 kcal m−2 yr−1 is very low compared with temperate zone populations, but is more similar as a percent of photosynthesis, 4.1%. The relatively large detritus pool and the presence of both 2- and 3-yr species tend to stabilize chironomid energy flow. Definition of long-term averages for chironomid populations in Char Lake would require a decade or more of study.

Central Otago - Built on gold, growing on grass.

2014 ◽  
Vol 76 ◽  
pp. 15-23
Author(s):  
Barrie J. Wills
Keyword(s):  
Economic Growth ◽  
Land Use ◽  
National Economy ◽  
Local Community ◽  
Central Government ◽  
Future Generations ◽  
Economic Potential ◽  
District Council ◽  
Definition Of

A warm welcome to our "World of Difference" to all delegates attending this conference - we hope your stay is enjoyable and that you will leave Central Otago with an enhanced appreciation of the diversity of land use and the resilient and growing economic potential that this region has to offer. Without regional wellbeing the national economy will struggle to grow, something Central Government finally seems to be realising, and the Central Otago District Council Long Term Plan 2012-2022 (LTP) signals the importance of establishing a productive economy for the local community which will aid in the economic growth of the district and seeks to create a thriving economy that will be attractive to business and residents alike. Two key principles that underpin the LTP are sustainability and affordability, with the definition of sustainability being "… development that meets the needs of the present without compromising the ability of future generations to meet their own needs."

Populism and Liberal Democracy

2019 ◽  
Author(s):  
Takis S. Pappas
Keyword(s):  
United States ◽  
Liberal Democracy ◽  
The United States ◽  
Comprehensive Theory ◽  
The People ◽  
Original Definition ◽  
Key Issues ◽  
Great Relevance ◽  
Definition Of

Based on an original definition of modern populism as “democratic illiberalism” and many years of meticulous research, Takis Pappas marshals extraordinary empirical evidence from Argentina, Greece, Peru, Italy, Venezuela, Ecuador, Hungary, the United States, Spain, and Brazil to develop a comprehensive theory about populism. He addresses all key issues in the debate about populism and answers significant questions of great relevance for today’s liberal democracy, including: • What is modern populism and how can it be differentiated from comparable phenomena like nativism and autocracy? • Where in Latin America has populism become most successful? Where in Europe did it emerge first? Why did its rise to power in the United States come so late? • Is Trump a populist and, if so, could he be compared best with Venezuela’s Chávez, France’s Le Pens, or Turkey’s Erdoğan? • Why has populism thrived in post-authoritarian Greece but not in Spain? And why in Argentina and not in Brazil? • Can populism ever succeed without a charismatic leader? If not, what does leadership tell us about how to challenge populism? • Who are “the people” who vote for populist parties, how are these “made” into a group, and what is in their minds? • Is there a “populist blueprint” that all populists use when in power? And what are the long-term consequences of populist rule? • What does the expansion, and possibly solidification, of populism mean for the very nature and future of contemporary democracy? Populism and Liberal Democracy will change the ways the reader understands populism and imagines the prospects of liberal democracy.

scholarly journals Effect of Barley Sowing Density on the Integrated Weed Management of Lolium rigidum (Annual Ryegrass) in Mediterranean Dryland: A Modeling Approach

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1565
Author(s):  
María Belén D’Amico ◽  
Guillermo R. Chantre ◽  
Guillermo L. Calandrini ◽  
José L. González-Andújar
Keyword(s):  
Weed Management ◽  
Life Cycles ◽  
Integrated Weed Management ◽  
Future Research ◽  
Seed Removal ◽  
Weed Infestation ◽  
High Control ◽  
Weed Dynamics ◽  
The Impact

Population models are particularly helpful for understanding long-term changes in the weed dynamics associated with integrated weed management (IWM) strategies. IWM practices for controlling L. rigidum are of high importance, mainly due to its widespread resistance that precludes chemical control as a single management method. The objective of this contribution is to simulate different IWM scenarios with special emphasis on the impact of different levels of barley sowing densities on L. rigidum control. To this effect, a weed–crop population model for both L. rigidum and barley life cycles was developed. Our results point out: (i) the necessity of achieving high control efficiencies (>99%), (ii) that the increase of twice the standard sowing density of barley resulted in a reduction of 23.7% of the weed density, (iii) non-herbicide-based individual methods, such as delayed sowing and weed seed removal at harvest, proved to be inefficient for reducing drastically weed population, (iv) the implementation of at least three control tactics (seed removal, delay sowing and herbicides) is required for weed infestation eradication independently of the sowing rate, and (v) the effect of an increase in the sowing density is diluted as a more demanding weed control is reached. Future research should aim to disentangle the effect of different weed resistance levels on L. rigidum population dynamics and the required efficiencies for more sustainable IWM programs.

scholarly journals “I’ve Heard of It, Yes, but I Can’t Remember What Exactly It Was”—A Qualitative Study on Awareness, Knowledge, and Use of the UV Index

2021 ◽  
Vol 18 (4) ◽  
pp. 1615
Author(s):  
Katharina Diehl ◽  
Tatiana Görig ◽  
Charlotte Jansen ◽  
Maike Carola Hruby ◽  
Annette B. Pfahlberg ◽  
...  
Keyword(s):  
Qualitative Study ◽  
Qualitative Content Analysis ◽  
Sun Protection ◽  
Structured Interviews ◽  
Protection Factor ◽  
Protection Measures ◽  
Uv Index ◽  
Correct Definition ◽  
Definition Of

Pharmacists and pharmaceutical technicians play an important role in counselling customers regarding sunscreen use and sun protection measures. A potentially helpful tool that can be used during counselling is the ultraviolet index (UVI), which informs individuals when and what sun protection measures are needed at a specific place and time. Our aim in this qualitative study was to explore awareness, knowledge, and use of the UVI during counselling in pharmacies. We used semi-structured interviews with pharmacists and pharmaceutical technicians (n = 20) to answer our research questions. Interviews were audiotaped, transcribed verbatim, and analyzed using qualitative content analysis. During the interviews pharmacists and pharmaceutical technicians revealed a lot of uncertainty and lack of knowledge regarding the UVI. Eight professionals were able to give a correct definition of UVI. Amongst others, the UVI was confused with sun protection factor. Overall, the UVI was hardly used during the counselling of customers. The UVI was developed to provide guidance when which type of sun protection is required to avoid detrimental effects of ultraviolet radiation. For effective implementation, both the general population and health professionals (e.g., pharmacists) have to increase their knowledge about the UVI. This would strengthen its use during professional counselling in pharmacies and may help to reduce the incidence of skin cancer over the long term.

scholarly journals It Is Not Just Mortality: A Call From Chile for Comprehensive COVID-19 Policy Responses Among Older People

2020 ◽  
Author(s):  
Pablo Villalobos Dintrans ◽  
Jorge Browne ◽  
Ignacio Madero-Cabib
Keyword(s):  
Older People ◽  
National Level ◽  
Health Issues ◽  
Negative Consequences ◽  
Access To Health Services ◽  
Term Care ◽  
Policy Responses ◽  
Level Data ◽  
Definition Of

Abstract Objective Provide a synthesis of the COVID-19 policies targeting older people in Chile, stressing their short- and long-term challenges. Method Critical analysis of the current legal and policy measures, based on national-level data and international experiences. Results Although several policies have been enacted to protect older people from COVID-19, these measures could have important unintended negative consequences in this group’s mental and physical health, as well as financial aspects. Discussion A wider perspective is needed to include a broader definition of health—considering financial scarcity, access to health services, mental health issues, and long-term care—in the policy responses to COVID-19 targeted to older people in Chile.

scholarly journals Cycles and circulation: a theme in the history of biology and medicine

2021 ◽  
Vol 43 (3) ◽  
Author(s):  
Nick Hopwood ◽  
Staffan Müller-Wille ◽  
Janet Browne ◽  
Christiane Groeben ◽  
Shigehisa Kuriyama ◽  
...  
Keyword(s):  
Natural Philosophy ◽  
Life Cycles ◽  
Modern Times ◽  
Systems Ecology ◽  
The Face ◽  
History Of ◽  
Celestial Bodies ◽  
Reproductive Cycles ◽  
Economics And Biology

AbstractWe invite systematic consideration of the metaphors of cycles and circulation as a long-term theme in the history of the life and environmental sciences and medicine. Ubiquitous in ancient religious and philosophical traditions, especially in representing the seasons and the motions of celestial bodies, circles once symbolized perfection. Over the centuries cyclic images in western medicine, natural philosophy, natural history and eventually biology gained independence from cosmology and theology and came to depend less on strictly circular forms. As potent ‘canonical icons’, cycles also interacted with representations of linear and irreversible change, including arrows, arcs, scales, series and trees, as in theories of the Earth and of evolution. In modern times life cycles and reproductive cycles have often been held to characterize life, in some cases especially female life, while human efforts selectively to foster and disrupt these cycles have harnessed their productivity in medicine and agriculture. But strong cyclic metaphors have continued to link physiology and climatology, medicine and economics, and biology and manufacturing, notably through the relations between land, food and population. From the grand nineteenth-century transformations of matter to systems ecology, the circulation of molecules through organic and inorganic compartments has posed the problem of maintaining identity in the face of flux and highlights the seductive ability of cyclic schemes to imply closure where no original state was in fact restored. More concerted attention to cycles and circulation will enrich analyses of the power of metaphors to naturalize understandings of life and their shaping by practical interests and political imaginations.

Probabilistic Analysis of Random Structural Intensity for Structural Members under Stochastic Loadings

2015 ◽  
Vol 12 (03) ◽  
pp. 1550013 ◽  
Author(s):  
Siu-Siu Guo ◽  
Dongfang Wang ◽  
Zishun Liu
Keyword(s):  
Energy Flow ◽  
Early Stage ◽  
Structural Members ◽  
Structural Intensity ◽  
Dynamic Loadings ◽  
Arbitrary Section ◽  
Stationary Loading ◽  
Fpk Equation ◽  
Definition Of ◽  
Probability Density Function Pdf

The concept of structural intensity (SI) is extended to the random domain by introducing a physical quantity denominated random structural intensity (RSI). This quantity is formulated for mechanical systems whose dynamical responses are stochastic due to random excitations. In order to fully characterize the stochastic behavior of a system under random loadings, it is imperative to obtain the probability density function (PDF) of RSI. Based on the elastic theory and the definition of SI, RSI is expressed as functions of system responses. In general, the PDF of system responses is governed by Fokker–Planck–Kolmogorov (FPK) equation under the assumption that random dynamic loadings are idealized as white noise excitations. Therefore, the PDF of RSI is derived with the joint PDF of system responses. In the present study, four demonstrating cases of beams and plates under separately concentrated and uniform random loadings are studied to investigate the properties of RSI. Stationary and non-stationary PDFs of RSI at arbitrary section of beam and plate are obtained. Numerical results show that the PDF of RSI is transient at early stage of stationary loading and then converges to the exact stationary ones as time increases. With the obtained PDFs of RSI, energy transmission path over the beam and plate can be determined, which is guided from the locations with lower probabilities of RSI to the ones with higher probabilities of RSI. Furthermore, virtual energy flow sinks on the plate and beam can be found, which are identified by the locations with the maximum probabilities of RSI.

Walleye (Stizostedion vitreum vitreum) and Yellow Perch (Perca flavescens) Populations and Fisheries of the Red Lakes, Minnesota, 1930–75

1977 ◽  
Vol 34 (10) ◽  
pp. 1774-1783 ◽  
Author(s):  
Lloyd L. Smith Jr.
Keyword(s):  
Growth Rate ◽  
Yellow Perch ◽  
Climatic Factors ◽  
Perca Flavescens ◽  
Growing Season ◽  
Commercial Fishery ◽  
Class Strength ◽  
Parent Stock ◽  
Catch Statistics

In an investigation of the commercial fishery of Red Lakes, Minnesota, for the 46-yr period 1930–75, catch statistics were analyzed, and the dynamics of the perch and walleye populations were examined. Mean annual yields of walleye for two statistical periods, 1930–53 and 1954–75, were 309,900 and 245,100 kg, respectively for walleyes, and 96,400 and 109,500 kg for perch. Annual abundance (CPE based on average catches per day per 5-net units of gill nets) varied from 3.8 to 64.6 kg for walleye, and from 2.5 to 34.4 kg for perch. Causes of fluctuations in harvestable stock were directly related to strength of year-classes and to growth rate during the season of capture. Year-class strength was not related to the abundance of parent stock or of potential predators. The respective strengths of year-classes of perch and walleye in the same year were positively correlated (r = 0.859, P < 0.01), and are directly related to climatic factors. Growth rate of walleye in different calendar years varied from +30.7 to −42.2% of mean growth, and that of perch from +13.4 to −8.6% (1941–56). Growing season began in mid-June and was almost over by September 1. Walleye yield could be enhanced by starting harvest July 1 instead of early June. Perch yield could be improved by harvesting small perch. Key words: Percidae, Perca, population dynamics, Stizostedion, long-term yield

scholarly journals When does proton pump inhibitor treatment become long term? A scoping review

2021 ◽  
Vol 8 (1) ◽  
pp. e000563
Author(s):  
Peter Fentz Haastrup ◽  
Dorte Ejg Jarbøl ◽  
Wade Thompson ◽  
Jane Møller Hansen ◽  
Jens Søndergaard ◽  
...  
Keyword(s):  
Proton Pump Inhibitor ◽  
Proton Pump ◽  
Cochrane Library ◽  
Clinical Context ◽  
Eligibility Criteria ◽  
Proton Pump Inhibitor Treatment ◽  
Common Definition ◽  
Definition Of ◽  
Inhibitor Treatment

ObjectiveProton pump inhibitor (PPI) use has risen substantially, primarily driven by ongoing use over months to years. However, there is no consensus on how to define long-term PPI use. Our objectives were to review and compare definitions of long-term PPI use in existing literature and describe the rationale for each definition. Moreover, we aimed to suggest generally applicable definitions for research and clinical use.DesignThe databases PubMed and Cochrane Library were searched for publications concerning long-term use of PPIs and ClinicalTrials.gov was searched for registered studies. Two reviewers independently screened the titles, abstracts, and full texts in two series and subsequently extracted data.ResultsA total of 742 studies were identified, and 59 met the eligibility criteria. In addition, two ongoing studies were identified. The definition of long-term PPI use varied from >2 weeks to >7 years. The most common definition was ≥1 year or ≥6 months. A total of 12/61 (20%) of the studies rationalised their definition.ConclusionThe definitions of long-term PPI treatment varied substantially between studies and were seldom rationalised.In a clinical context, use of PPI for more than 8 weeks could be a reasonable definition of long-term use in patients with reflux symptoms and more than 4 weeks in patients with dyspepsia or peptic ulcer. For research purposes, 6 months could be a possible definition in pharmacoepidemiological studies, whereas studies of adverse effects may require a tailored definition depending on the necessary exposure time. We recommend to always rationalise the choice of definition.

scholarly journals The evolving definition of salivary gland stem cells

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Cecilia Rocchi ◽  
Lara Barazzuol ◽  
Rob P. Coppes
Keyword(s):  
Stem Cells ◽  
Salivary Gland ◽  
Adult Stem Cell ◽  
Cell Types ◽  
Research Field ◽  
New Therapeutic Approaches ◽  
Recent Developments ◽  
Radiation Induced ◽  
Definition Of

AbstractDysfunction of the salivary gland and irreversible hyposalivation are the main side effects of radiotherapy treatment for head and neck cancer leading to a drastic decrease of the quality of life of the patients. Approaches aimed at regenerating damaged salivary glands have been proposed as means to provide long-term restoration of tissue function in the affected patients. In studies to elucidate salivary gland regenerative mechanisms, more and more evidence suggests that salivary gland stem/progenitor cell behavior, like many other adult tissues, does not follow that of the hard-wired professional stem cells of the hematopoietic system. In this review, we provide evidence showing that several cell types within the salivary gland epithelium can serve as stem/progenitor-like cells. While these cell populations seem to function mostly as lineage-restricted progenitors during homeostasis, we indicate that upon damage specific plasticity mechanisms might be activated to take part in regeneration of the tissue. In light of these insights, we provide an overview of how recent developments in the adult stem cell research field are changing our thinking of the definition of salivary gland stem cells and their potential plasticity upon damage. These new perspectives may have important implications on the development of new therapeutic approaches to rescue radiation-induced hyposalivation.

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