scholarly journals Costs and benefits of Daphnia defense against Chaoborus in nature

2005 ◽  
Vol 62 (6) ◽  
pp. 1286-1294 ◽  
Author(s):  
Wiebke J Boeing ◽  
Björn Wissel ◽  
Charles W Ramcharan
Keyword(s):  
Population Growth ◽  
Daphnia Pulex ◽  
Costs And Benefits ◽  
Short Term ◽  
Cost Of Defense ◽  
Daphnia Population ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Cost

To estimate costs and benefits of antipredator defenses in the Chaoborus–Daphnia system, we employed lake enclosures wherein controls (C) had no predators, the predation (P) treatment had freely swimming Chaoborus, and the kairomone (K) treatment predators were sequestered in a mesh tube apart from the Daphnia. Population growth (r) of two Daphnia pulex clones, one responsive (RC) and the other nonresponsive (NRC) to Chaoborus kairomone, was estimated for each predator treatment. Cost of defense was calculated as r(C,RC) – r(K,RC). Benefit was calculated as r(P,RC) – r(P,NRC). Antipredator defenses of Daphnia towards Chaoborus kairomone led to a 32% reduction in population growth in nature. The benefit of the defense, however, was a short-term 68% enhanced population growth by a responsive over a nonresponsive clone in the presence of the actual predation threat. The benefit of the defense exceeded the cost, but cost was nevertheless substantial. Our results verify that the in situ effects of Chaoborus on Daphnia involve direct and indirect impacts.

An in situ test of the effects of food quality on Daphnia population growth

1995 ◽  
pp. 221-230
Author(s):  
Bart T. De Stasio ◽  
Lars G. Rudstam ◽  
Adrienne Haning ◽  
Pat Soranno ◽  
Yvonne C. Allen
Keyword(s):  
Population Growth ◽  
Food Quality ◽  
In Situ Test ◽  
Daphnia Population

Quantifying percentage cover of subtidal organisms on rocky coasts: a comparison of the costs and benefits of standard methods

2005 ◽  
Vol 56 (6) ◽  
pp. 865 ◽  
Author(s):  
S. P. Drummond ◽  
S. D. Connell
Keyword(s):  
Benthic Algae ◽  
Costs And Benefits ◽  
Percentage Cover ◽  
Sessile Invertebrates ◽  
Time Required ◽  
Taxonomic Groups ◽  
The Cost ◽  
Regular Arrays ◽  
Laboratory Time

This study compares the cost (time and funds) and benefits (precision and accuracy) of methods commonly used to estimate percentage cover of sessile marine organisms. We applied nine methods to morphological groups of benthic algae and broad taxonomic groups of sessile invertebrates; including varying the intensity of sampling (25 v. 50 v. 100 point-intercepts), random v. regular arrays, in situ v. laboratory v. photographic sampling v. computer digitising. We detected little to no difference in estimates of percentage cover among methods, indicating that accuracy is unlikely to be an important issue that distinguishes methods. Precision was generally unaffected by the intensity of sampling within quadrats (25 v. 50 v. 100 point-intercepts) or between environments (in situ v. on photographs v. within the laboratory) and appeared to be of secondary concern to decisions about replication. Computer digitising (estimates of surface area of each taxon) provided the least precise estimates and did not justify the additional laboratory time required to process them. Depending on whether field expenses or laboratory expenses are of the greatest concern, the techniques that permit the greatest coverage of area (greatest replication) are likely to produce the most representative (accurate) and reliable (precise) estimates.

An in situ test of the effects of food quality on Daphnia population growth

Hydrobiologia ◽  
1995 ◽  
Vol 307 (1-3) ◽  
pp. 221-230 ◽  
Author(s):  
Bart T. De Stasio ◽  
Lars G. Rudstam ◽  
Adrienne Haning ◽  
Pat Soranno ◽  
Yvonne C. Allen
Keyword(s):  
Population Growth ◽  
Food Quality ◽  
In Situ Test ◽  
Daphnia Population

scholarly journals Faktor yang Memengaruhi Pemilihan Metode Kontrasepsi

2017 ◽  
Vol 5 (2) ◽  
pp. 91
Author(s):  
Rendys Septalia ◽  
Nunik Puspitasari
Keyword(s):  
Mental Health ◽  
Population Growth ◽  
Contraceptive Use ◽  
Drop Out ◽  
Contraceptive Methods ◽  
Short Term ◽  
Contraceptive Usage ◽  
Material Costs ◽  
The Cost

Contraception was the most effective way to control the population growth. The most widely favored in Indonesia was a short-term contraceptive methods. High attainment acceptor on short-term contraceptive methods because short-term contraceptive methods was a methods contraception affordable, while the fees for the long-term contraceptive methods was more expensive. The incidence of injectable contraceptives and pills drop-out was higher than the long-term contraceptive methods that contributed to the failure of population growth control program. This study to analyze the factors that affect the selection contraceptive methods. This study was an observational study with cross sectional design. Sampling with systematic random and obtained were 79 acceptors. The independent variables were the cost of contraceptive use, non-material costs (experience side effects), cultural obstacle, social adjustments obstacle, physic and mental health obstacle, and accessibility obstacle. Data collected using the questionnaire and analyse by multiple logistic regression. The results showed that the significant factor were the cost of contraceptive usage (pvalue = 0.002), the cost of non-material (experience side eff ects) (pvalue = 0.007), and factors that didn’t have signifi cant influence were cultural obstacle (pvalue = 0.105), social adjustments obstacle (pvalue = 0.999), physic and mental health obstacle (pvalue = 0.920), and accessibility obstacle (pvalue = 0.438). The conclusion were the cost of contraceptive use and non-material costs (experience side eff ects) aff ected the selection of contraception. It was need the cooperation between religious leaders, community leaders, and health care workers in a common understanding on the cost of contraceptive usage.

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.

Organizational Networks and Recovery following the Canterbury Earthquakes

2014 ◽  
Vol 30 (1) ◽  
pp. 555-575 ◽  
Author(s):  
J. R. Stevenson ◽  
Y. Chang-Richards ◽  
D. Conradson ◽  
S. Wilkinson ◽  
J. Vargo ◽  
...  
Keyword(s):  
Organizational Behavior ◽  
Support Network ◽  
Organizational Networks ◽  
Short Term ◽  
Network Characteristics ◽  
Organizational Case Studies ◽  
Regional Reconstruction ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts

Following a disaster, the recovery of organizations is influenced by the flow of resources and information through organizational networks. The 2010–2011 earthquakes in Canterbury, New Zealand, had major direct and indirect impacts on local organizations and the regional economy. This paper utilizes 47 organizational case studies to assess the role of organizations’ networks in their response and short-term recovery activities, and to explore the effects of networks on regional reconstruction and related sectors. The results are organized around four thematic analyses, focusing on organizations’ support network characteristics, the types of support mobilized to aid recovery, network adaptations for new post-quake demands, and the economic impacts of organizational networks in reconstruction. The paper discusses how organizations managed and utilized networks to reduce the impacts of the earthquakes and to adapt to altered post-quake environments. These empirical observations of post-quake organizational behavior can also inform regional economic impact and resilience modeling.

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

2017 ◽  
Author(s):  
Francois Tuzet ◽  
Marie Dumont ◽  
Matthieu Lafaysse ◽  
Ghislain Picard ◽  
Laurent Arnaud ◽  
...  
Keyword(s):  
Near Infrared ◽  
Solar Spectrum ◽  
Snow Melt ◽  
Near Surface ◽  
Deposition Fluxes ◽  
Radiative Impacts ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
Total Impact

Abstract. Light-absorbing impurities decrease snow albedo, increasing the amount of solar energy absorbed by the snowpack. Its most intuitive and direct impact is to accelerate snow melt. 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 (hereafter referred 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 melt water. Taking benefits of the recent inclusion of the spectral radiative transfer model TARTES in Crocus, the model explicitly represents the radiative impacts of light-absorbing impurities in snow. The model was evaluated at 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 and dust deposition fluxes used to drive the model were extracted from simulations of the atmospheric model ALADIN-Climate. The model simulates reasonably snowpack evolution in term of snow depth, snow water equivalent and near-surface specific surface area. Indeed, the model performances are not deteriorated compared to our reference Crocus version, while explicitly representing the impact of light-absorbing impurities. We show that the deposition fluxes from 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 from 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 snow melt and avalanche prediction.

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.

scholarly journals Social dilemma in the external immune system of the red flour beetle? It is a matter of time

2017 ◽  
Author(s):  
Chaitanya S. Gokhale ◽  
Arne Traulsen ◽  
Gerrit Joop
Keyword(s):  
Immune System ◽  
Public Good ◽  
Social Dilemma ◽  
Red Flour Beetle ◽  
Costs And Benefits ◽  
Short Term ◽  
Flour Beetle ◽  
Experimental Systems ◽  
Long Run ◽  
The Cost

Sociobiology has revolutionized our understanding of interactions between organisms. Interactions may present a social dilemma where the interests of individual actors do not align with those of the group as a whole. Viewed through a sociobiological lens, nearly all interactions can be described in terms of their costs and benefits and a number of them then resemble a social dilemma. Numerous experimental systems, from bacteria to mammals, have been proposed as models for studying such dilemmas. Here we make use of the external immune system of the red flour beetle, Tribolium castaneum, to investigate how the experimental duration can affect whether the external secretion comprises a social dilemma or not. Some beetles (secretors) produce a costly quinone-rich external secretion that inhibits microbial growth in the surrounding environment, providing the secretors with direct personal benefits. However, since the antimicrobial secretion acts in the environment of the beetle it is potentially also advantageous to other beetles (non-secretors), who avoid the cost of producing the secretion. We test experimentally if the secretion qualifies as a public good. We find that in the short term, costly quinone secretion can be interpreted as a public good presenting a social dilemma where the presence of secretors increases the fitness of the group. In the long run, the benefit to the group of having more secretors vanishes and actually becomes detrimental to the group. Therefore, in such semi-natural environmental conditions, it turns out that qualifying a trait as social can be a matter of timing.

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