Impact of Permethrin on Zooplankton Communities in Limnocorrals

1985 ◽  
Vol 42 (1) ◽  
pp. 77-85 ◽  
Author(s):  
N. K. Kaushik ◽  
G. L. Stephenson ◽  
K. R. Solomon ◽  
K. E. Day
Keyword(s):  
Acute Toxicity ◽  
Zooplankton Community ◽  
Exposure Concentration ◽  
Natural Conditions ◽  
Southern Ontario ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
Zooplankton Communities ◽  
The Impact

A series of in situ aquatic enclosures or limnocorrals (5 × 5 × 5 m deep) was used to evaluate the impact of the insecticide permethrin (3-phenoxybenzy[(1RS)-cis,trans-3-(2,2-dimethyl-3-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate) (50.0 and 5.0 μg∙L−1 in 1979 and 5.0 and 0.5 μg∙L−1 in 1980) on the pelagic zooplankton community in a 10-ha mesotrophic lake in southern Ontario. Permethrin was acutely toxic to the macrozooplankton (Cladocera and Copepoda) at all concentrations; microzooplankton (Rotifera) showed acute toxicity only at 50.0 μg∙L−1. Despite this initial toxicity, the density of microzooplankton increased dramatically 15–20 d post-treatment in all treated enclosures, and the rotifer populations dominated the zooplankton community for 3–4 wk. The high densities of microzooplankton were attributed to their inherent reproductive capabilities when released from competition and predation pressures. Resilience of the different zooplankton taxa was variable and depended upon both the species and the exposure concentration. Diversity of zooplankton was significantly reduced in communities exposed to permethrin. The limnocorral technique has proved to be an important tool for assessment of direct and indirect impacts of pesticides on and probable recovery of a zooplankton community under natural conditions.

Perturbations in Zooplankton Communities in a Continuously Flowing Impoundment System Incubated in situ

1987 ◽  
Vol 44 (S1) ◽  
pp. s154-s162 ◽  
Author(s):  
M. H. Holoka ◽  
S. G. Lawrence
Keyword(s):  
Lake Water ◽  
Zooplankton Community ◽  
Zooplankton Species ◽  
Natural Conditions ◽  
Toxic Materials ◽  
Similarity Indices ◽  
Self Powered ◽  
Percent Similarity ◽  
Zooplankton Communities

An apparatus which draws lake water, either filtered or unaltered, at a preestablished rate through four 40.75 L vessels incubated in situ is described. The system provides facilities for the synchronous addition of experimental liquids such as toxicants. All components are readily transportable. The system is self-powered for periods up to one month depending on the rate of flow chosen. This apparatus provides for the isolation of the zooplankton community from other compartments in the lake, incubation in natural conditions, experimental periods of from 1 to 30 d, maintenance of chosen concentrations of added materials continuously or non-continuously as appropriate, and entry of food organisms with concomitant dilution of wastes and metabolites.The responses of selected zooplankton species or of zooplankton communities to impoundment, manipulation of predator or prey organisms and the addition of nutrient or toxic materials can be assessed as they occur in the naturally varying conditions of a lake environment while the population is being held as a separate and defined part of the whole-lake ecosystem.Methods for the construction and use of the apparatus, and for collection of samples are described. Methods for enumerating organisms in several sizes of subsamples are assessed. Data generated in several experiments are analyzed using standard statistical methods and percent similarity indices.

scholarly journals Impact of Entrepreneurship Extracurricular Activities and Inspiration on Entrepreneurial Intention: Mediator and Moderator Effect

SAGE Open ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 215824402110321
Author(s):  
Thuy Thu Nguyen ◽  
Linh Thi Phuong Nguyen ◽  
Hoa Thi Thanh Phan ◽  
Anh Trong Vu
Keyword(s):  
Extracurricular Activities ◽  
Structural Equation ◽  
Entrepreneurial Intention ◽  
Equation Modeling ◽  
Moderator Effect ◽  
Technical Students ◽  
Research Findings ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Impact

This empirical study proposed a comprehensive model testing the direct and indirect impacts of entrepreneurship extracurricular activities and entrepreneurship inspiration on students’ entrepreneurial intention. With the sample consisting of 640 students from 11 universities in Vietnam, the study used structural equation modeling analysis approach. The results revealed that entrepreneurship extracurricular activities and entrepreneurship inspiration are significantly related to students’ entrepreneurial intention, and entrepreneurship self-efficacy partially mediates these relations. The impact of entrepreneurship education on entrepreneurial intention differs across the field of study. Technical students generally get more benefits from entrepreneurship educational activities than business and economics students do. The research findings recommended some implications for fostering graduates’ entrepreneurship in emerging countries.

scholarly journals The Impact of the Physical Environment on Intrapartum Maternity Care: Identification of Eight Crucial Building Spaces

2019 ◽  
Vol 12 (4) ◽  
pp. 67-98
Author(s):  
Nicoletta Setola ◽  
Eletta Naldi ◽  
Grazia Giulia Cocina ◽  
Liv Bodil Eide ◽  
Laura Iannuzzi ◽  
...  
Keyword(s):  
Maternity Care ◽  
Physical Environment ◽  
Architectural Design ◽  
Well Being ◽  
Physical Characteristics ◽  
Interdisciplinary Studies ◽  
Room Size ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Impact

Objectives, Purpose, or Aim: This article investigates whether the physical environment in which childbirth occurs impacts the intrapartum intervention rates and how this might happen. The study explores the spatial physical characteristics that can support the design of spaces to promote the health and well-being of women, their supporters, and maternity care professionals. Background: Medical interventions during childbirth have consequences for the health of women and babies in the immediate and long term. The increase in interventions is multifactorial and may be influenced by the model of care adopted, the relationships between caregivers and the organizational culture, which is made up of many factors, including the built environment. In the field of birth architecture research, there is a gap in the description of the physical characteristics of birth environments that impact users’ health. Method: A scoping review on the topic was performed to understand the direct and indirect impacts of the physical environment on birth intervention rates. Results and Discussion: The findings are organized into three tables reporting the influence that the physical characteristics of a space might have on people’s behaviors, experiences, practices and birth health outcomes. Eight building spaces that require further investigation and research were highlighted: unit layout configuration, midwives’ hub/desk, social room, birth philosophy vectors, configuration of the birth room, size and shape of the birth room, filter, and sensory elements. Conclusions: The findings show the importance of considering the physical environment in maternity care and that further interdisciplinary studies focused on architectural design are needed to enrich the knowledge and evidence on this topic and to develop accurate recommendations for designers.

The impact of two Chaoborus species on a zooplankton community

1990 ◽  
Vol 68 (5) ◽  
pp. 981-985 ◽  
Author(s):  
Neil A. MacKay ◽  
Stephen R. Carpenter ◽  
Patricia A. Soranno ◽  
Michael J. Vanni
Keyword(s):  
Chlorophyll A ◽  
Daphnia Pulex ◽  
Zooplankton Community ◽  
Chlorophyll A Concentration ◽  
Chaoborus Flavicans ◽  
Chaoborus Americanus ◽  
Diaptomus Oregonensis ◽  
Herbivore Responses ◽  
The Impact

The responses of a zooplankton community to Chaoborus predation were studied in large in situ mesocosms in Peter Lake. Chaoborus flavicans, the native chaoborid, significantly reduced the density of the dominant grazer, Daphnia pulex, in relation to controls that lacked Chaoborus. Chaoborus americanus, a species found only in fishless bogs, reduced Da. pulex densities far more than the chaoborid found in Peter Lake, C. flavicans. Chaoborus americanus also significantly reduced the dominant copepod, Diaptomus oregonensis, in relation to both the control and the C. flavicans treatment. Chlorophyll a concentration did not differ among treatments, indicating that herbivore responses could not be explained by changes in food levels. Our results show that Chaoborus predation can greatly affect a zooplankton community, especially daphnids.

scholarly journals PERUBAHAN PENGELOLA DTW TANAH LOT DAN DAMPAKNYA TERHADAP MASYARAKAT LOKAL

2016 ◽  
Author(s):  
I Putu Krisna Arta Widana
Keyword(s):  
Qualitative Method ◽  
Local Community ◽  
Tourist Attraction ◽  
Private Land ◽  
Tourist Attractions ◽  
Tourist Satisfaction ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
Management Changes ◽  
The Impact

This article discusses the impact of the management changes ofTanah Lot tourist attraction on community of Beraban village,Tabanan, Bali, and efforts of the new management in realizing Tanah Lot as a sustainable tourist attraction. The research method used is a qualitative method with data collection techniques, namely observation, interviews, and documentation. The management changes of Tanah Lot tourist attraction have direct and indirect impacts to the local community. The impacts are divided into three aspects, namely physical, social cultural and economic aspect. Efforts made by the new management in order to realize Tanah Lot includes adding tourist attractions, tourism facilities, distributes the location of trade, organising and supervising activities of the tourism business, and forming a group of merchants as well as establishing good relationship and communication with private land owner. Indicators used as a benchmark is the Magic Pentagon, namely a healthy economy,the welfare of the local community, does not change the natural,healthy culture, and tourist satisfaction.

The Impact of Macro Economics on Firm Values and Financial Performance as an Intervening Variable: An Empirical Study of LQ-45 Banking Industries in Indonesia

2015 ◽  
Vol 3 (1) ◽  
pp. 88-94
Author(s):  
Indra Siswanti ◽  
Eko Ganis Sukoharsono ◽  
Embun Prowanta
Keyword(s):  
Exchange Rate ◽  
Central Bank ◽  
Exchange Rates ◽  
Financial Performance ◽  
Firm Value ◽  
Return On Assets ◽  
Bank Rate ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Impact

Objective - The Purpose of the paper is to empirically investigate both direct and indirect impacts of the macro economy, which are Exchange Rates, Inflation, Central Bank Rate, as independent variables, on Value Firms (Price to Book Value), as a dependent variable, and its Financial Performance (Return on Assets), as an interning variable. Methodology/Technique - The study uses a path analytical method of the SPSS for determining a strong causal relationship between the independent variable and the dependent variable either directly or indirectly. Findings - The paper finds that Exchange Rate does not impact on ROA; Inflation negative significantly impacts on ROA; Central Bank Rates positive significantly impact on ROA; ROA does not impact on PBV; Exchange Rate negative significantly impact on PBV; Inflation does not impact on PBV; Central Bank Rate does not impact on PBV; ROA does not mediate its impact of Exchange Rates on Firm Value (PBV); ROA does not mediate its impact of Inflation on Firm Value (PBV) Dan ROA mediate its impact of Central Bank Rates on Firm Value (PBV).. Novelty - The paper uses corporate performance (Return on Assets) as an intervening variable to test the indirect effect on firm values (PBV). Type of Paper - Empirical Keywords: Exchange Rates, Inflation, Central Bank Rates, Return on Assets and Firm Values (PBV)

scholarly journals A multilayer physically based snowpack model simulating direct and indirect radiative impacts of light-absorbing impurities in snow

2017 ◽  
Vol 11 (6) ◽  
pp. 2633-2653 ◽  
Author(s):  
Francois Tuzet ◽  
Marie Dumont ◽  
Matthieu Lafaysse ◽  
Ghislain Picard ◽  
Laurent Arnaud ◽  
...  
Keyword(s):  
Near Infrared ◽  
Solar Spectrum ◽  
Direct Impact ◽  
Near Surface ◽  
Deposition Fluxes ◽  
Radiative Impacts ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
Total Impact

Abstract. Light-absorbing impurities (LAIs) decrease snow albedo, increasing the amount of solar energy absorbed by the snowpack. Its most intuitive and direct impact is to accelerate snowmelt. Enhanced energy absorption in snow also modifies snow metamorphism, which can indirectly drive further variations of snow albedo in the near-infrared part of the solar spectrum because of the evolution of the near-surface snow microstructure. New capabilities have been implemented in the detailed snowpack model SURFEX/ISBA-Crocus (referred to as Crocus) to account for impurities' deposition and evolution within the snowpack and their direct and indirect impacts. Once deposited, the model computes impurities' mass evolution until snow melts out, accounting for scavenging by meltwater. Taking advantage of the recent inclusion of the spectral radiative transfer model TARTES (Two-stream Analytical Radiative TransfEr in Snow model) in Crocus, the model explicitly represents the radiative impacts of light-absorbing impurities in snow. The model was evaluated at the Col de Porte experimental site (French Alps) during the 2013–2014 snow season against in situ standard snow measurements and spectral albedo measurements. In situ meteorological measurements were used to drive the snowpack model, except for aerosol deposition fluxes. Black carbon (BC) and dust deposition fluxes used to drive the model were extracted from simulations of the atmospheric model ALADIN-Climate. The model simulates snowpack evolution reasonably, providing similar performances to our reference Crocus version in terms of snow depth, snow water equivalent (SWE), near-surface specific surface area (SSA) and shortwave albedo. Since the reference empirical albedo scheme was calibrated at the Col de Porte, improvements were not expected to be significant in this study. We show that the deposition fluxes from the ALADIN-Climate model provide a reasonable estimate of the amount of light-absorbing impurities deposited on the snowpack except for extreme deposition events which are greatly underestimated. For this particular season, the simulated melt-out date advances by 6 to 9 days due to the presence of light-absorbing impurities. The model makes it possible to apportion the relative importance of direct and indirect impacts of light-absorbing impurities on energy absorption in snow. For the snow season considered, the direct impact in the visible part of the solar spectrum accounts for 85 % of the total impact, while the indirect impact related to accelerated snow metamorphism decreasing near-surface specific surface area and thus decreasing near-infrared albedo accounts for 15 % of the total impact. Our model results demonstrate that these relative proportions vary with time during the season, with potentially significant impacts for snowmelt and avalanche prediction.

ADVANTAGES AND DISADVANTAGES OF BURNING SPILLED OIL

1993 ◽  
Vol 1993 (1) ◽  
pp. 765-772 ◽  
Author(s):  
Alan A. Allen ◽  
Ronald J. Ferek
Keyword(s):  
Oil Spills ◽  
Full Potential ◽  
Advantages And Disadvantages ◽  
Oil Spill Response ◽  
Direct And Indirect Impacts ◽  
World Information ◽  
Indirect Impacts ◽  
Spill Control ◽  
Offshore Oil

ABSTRACT The full potential for in situ burning as a controlled oil spill response technique is a subject of growing interest throughout the world. Information now available from burning oil during accidental fires, war-related fires in Kuwait, spillage from the Exxon Valdez, and controlled test burns, permits an objective and comprehensive assessment of both the positive and negative aspects of in situ burning. A thorough analysis has been made of direct and indirect impacts and concerns typically associated with the decision, to burn or not to burn. These factors, together with the comparative costs of various response techniques, have been identified and described to provide spill control planners and response organizations with a means of assessing the potential use of burning to clean up offshore oil spills.

scholarly journals Zooplankton Community Responses to Oxygen Stress

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 706 ◽  
Author(s):  
Maciej Karpowicz ◽  
Jolanta Ejsmont-Karabin ◽  
Joanna Kozłowska ◽  
Irina Feniova ◽  
Andrew R. Dzialowski
Keyword(s):  
Zooplankton Community ◽  
Oxygen Depletion ◽  
Zooplankton Biomass ◽  
Oxygen Stress ◽  
Carbon Transfer ◽  
Oxygen Conditions ◽  
Anoxic Layer ◽  
Zooplankton Communities ◽  
The Impact

Recent changes in climate and eutrophication have caused increases in oxygen depletion in both freshwater and marine ecosystems. However, the impact of oxygen stress on zooplankton, which is the major trophic link between primary producers and fish, remains largely unknown in lakes. Therefore, we studied 41 lakes with different trophic and oxygen conditions to assess the role of oxygen stress on zooplankton communities and carbon transfer between phytoplankton and zooplankton. Samples were collected from each lake at the peak of summer stratification from three depth layers (the epilimnion, metalimnion, and hypolimnion). Our results revealed that freshwater zooplankton were relatively tolerant to anoxic conditions and the greatest changes in community structure were found in lakes with the highest oxygen deficits. This caused a switch in dominance from large to small species and reduced the zooplankton biomass in lower, anoxic layers of water, but not in the upper layers of water where the oxygen deficits began. This upper anoxic layer could thus be a very important refuge for zooplankton to avoid predation during the day. However, the reduction of zooplankton in the lower water layers was the main factor that reduced the effectiveness of carbon transfer between the phytoplankton and zooplankton.

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