scholarly journals The benefits of bathing buds: water calyces protect flowers from a microlepidopteran herbivore

2007 ◽  
Vol 3 (4) ◽  
pp. 405-407 ◽  
Author(s):  
Jane E Carlson ◽  
Kyle E Harms
Keyword(s):  
Experimental Manipulation ◽  
Water Levels ◽  
Negative Effects ◽  
Floral Herbivory ◽  
Flower Production ◽  
Egg Deposition ◽  
Morphological Adaptations ◽  
Plant Flower

Protective floral structures may evolve in response to the negative effects of floral herbivores. For example, water calyces—liquid-filled, cup-like structures resulting from the fusion of sepals—may reduce floral herbivory by submerging buds during their development. Our observations of a water-calyx plant, Chrysothemis friedrichsthaliana (Gesneriaceae), revealed that buds were frequently attacked by ovipositing moths (Alucitidae), whose larvae consumed anthers and stigmas before corollas opened. Almost 25% of per-plant flower production was destroyed by alucitid larvae over two seasons, far exceeding the losses to all other floral herbivores combined. Experimental manipulation of water levels in calyces showed that a liquid barrier over buds halved per-flower alucitid egg deposition and subsequent herbivory, relative to buds in calyces without water. Thus, C. friedrichsthaliana 's water calyx helps protect buds from a highly detrimental floral herbivore. Our findings support claims that sepal morphology is largely influenced by selection to reduce floral herbivory, and that these pressures can result in novel morphological adaptations.

Life History of Redside Shiners, Richardsonius balteatus, with Particular Reference to Movements In and Out of Sixteenmile Lake Streams

1963 ◽  
Vol 20 (4) ◽  
pp. 1001-1030 ◽  
Author(s):  
C. C. Lindsey ◽  
T. G. Northcote
Keyword(s):  
Life History ◽  
Fork Length ◽  
Water Levels ◽  
Daily Maximum ◽  
Egg Deposition ◽  
Maximum Water Temperature ◽  
History Of ◽  
Maximum Water ◽  
Richardsonius Balteatus ◽  
Downstream Movement

Movements of shiners through two-way traps on inlet and outlet streams of a small British Columbia lake were studied from 1956 to 1962. The date on which adults first entered the inlet each spring corresponded to the first rise of daily maximum stream temperature above 10 °C. Days on which increased numbers of shiners ascended the inlet were positively associated with days of rising daily maximum water temperature, and were not associated with water levels. Egg deposition occurred both in daylight and darkness. Downstream movement of shiner fry was greatest during periods of turbidity, and occurred largely during darkness. Shiners first spawned at age III or older; some lived to age V or VI. Number of adult shiners over 79 mm fork length was estimated by Petersen marking experiments to be about 13,000 in the 42-acre lake. A large interchange of adults took place in some years between the lake and parts of the watershed upstream; a small interchange occurred downstream. Many shiners entered a stream more than once each year. Many survived to spawn in two or more successive years. Movement into the streams varied markedly in different years and was small compared with the number of adults in the lake. Homing is suggested as a mechanism which determines the proportion of inlet-, outlet-, and lake-spawning in this species.

Study on Effects of Environment Conditions on Essential Service Water System of Nuclear Power Station

2017 ◽  
Author(s):  
Yang Ting ◽  
Li Guang Sheng ◽  
Li Zeng Fen ◽  
Peng Yue ◽  
Hu Jian
Keyword(s):  
Environmental Conditions ◽  
Nuclear Power ◽  
Water System ◽  
Open Water ◽  
Water Levels ◽  
Negative Effects ◽  
Power Stations ◽  
Service Water ◽  
Physical And Chemical ◽  
Essential Service

For nuclear power stations, the main function of Essential Service Water System (ESWS) is to discharge the waste heat from reactor core and spent fuel pool to the environment controllably, which is directly related to the safety and economy of nuclear power stations. Usually ESWS use open water from sea, rivers, lakes, reservoirs, as heat transfer medium. Extremely harsh environmental conditions may disable system functions and even lead to ESWS failure, directly reduce the safety and economy of nuclear power stations, and cause serious nuclear accidents. Failure of ESWS is one of the main reasons that lead to the Fukushima nuclear accident because of the loss of electricity after the earthquake and tsunami. Based on the typical ESWS configuration and conditions of serving nuclear power stations in China, the influence of environmental conditions on the function of water system is studied, and the corresponding measures are analyzed. These conditions can be divided into three categories: temperatures, water levels, and physical and chemical characteristics. Temperatures affect cooling characteristic of ESWS mainly. Nuclear power stations in tropical areas need to focus on cooling capacity might be reduced by high temperature. Those in cold region need attention to excessive cooling and freezing problems caused by low temperature. The influence of water levels is mainly fluid transport capacity and selection of equipment to ESWS. When the range of natural water level is too wide, designers shall consider measures to narrow it, such as the construction of highly reliable reservoir. Inland nuclear power stations shall try to ensure the reliability of ESWS; prevent water level changes beyond the scope of design caused by drought and flood disasters. The effects of physical and chemical properties are derived from the open water characteristics, including high salinity, high chloride ion concentration, carrying solid particles, suspended solids, and aquatics, and so on. These characteristics will cause the equipment and pipeline eroded or even damaged, aqueducts of intake and output jammed, heat exchangers of the final heat sink weakened and other negative effects, resulting in ESWS performance decline. Some of these factors are the characteristics of station site natural environment, some others are changes caused by human activities. Some factors are sustained, long-term; some others may be sudden, temporary. Influence on these factors need to be taken measures from many aspects, including structure, biological disinfection, special materials and equipment, environmental protection measures around the nuclear power station, and so on. On the whole, the environmental factors that affect ESWS in the nuclear power stations are wide, and the influence mechanism is more complex. These factors ultimately act on ESWS, but most of them cannot be banished inside of ESWS or the final heat sink system. Against the negative effects from environmental conditions, it has to be considered from all steps in the engineering of nuclear power stations, including design, construction and operation. All the measures shall be suitable to local conditions, in order to ensure the safety and economy of nuclear power stations.

Groundwater management for adaptation under changing climate conditions in Indian Punjab

2013 ◽  
Vol 4 (1) ◽  
pp. 38-51 ◽  
Author(s):  
Samanpreet Kaur ◽  
Prit Pal Singh Lubana ◽  
Rajan Aggarwal
Keyword(s):  
Climate Change ◽  
Tamil Nadu ◽  
Groundwater Resources ◽  
Geographical Area ◽  
Water Levels ◽  
Negative Effects ◽  
Climate Conditions ◽  
Total Geographical Area ◽  
Over Exploitation ◽  
Agricultural Demand

India is the largest groundwater user in the world, with an estimated usage of around 230 km3 per year. Agricultural demand for irrigation is already the single largest draw on India's water, yet estimates by the Ministry of Water Resources indicate that by the year 2050 irrigation needs will rise by 56%. From the climate change viewpoint, India's groundwater hotspots are concentrated in the seven states of Punjab, Rajasthan, Maharashtra, Karnataka, Gujarat, Andhra Pradesh, and Tamil Nadu. The state of Punjab, with only 1.57% of the total geographical area, is contributing 27–40% rice, 55–65% wheat and 18–25% cotton to the central pool since the last three decades. The dropping water levels in these regions are largely attributed to unsustainable consumption of groundwater for irrigation and other uses along with increased runoff and/or evapotranspiration, which climate change may further exacerbate. This paper presents an overview of current groundwater issues and examines the potential and negative effects of climate change on the groundwater resources in Punjab. Therefore, in this paper an attempt has been made to analyze the problem of declining groundwater resources and possible factors responsible for this and suggest suitable strategies for arresting over-exploitation and for sustainable agriculture in Punjab.

scholarly journals Job (In)Security and Workers’ Training Decisions: A Framing Approach

2020 ◽  
Vol 7 (3) ◽  
pp. 361-387
Author(s):  
Pascal Kamphuis ◽  
Arie C. Glebbeek
Keyword(s):  
Decision Making ◽  
Labour Market ◽  
Experimental Manipulation ◽  
Multilevel Logistic Regression ◽  
Negative Effects ◽  
Balanced Design ◽  
Worker Training ◽  
Vignette Study ◽  
Labour Market Position ◽  
The Relationship

Context: In this study, we attempt to contribute to the scarce evidence about the relationship between perceived labour market insecurity and worker training investments. Drawing on existing research into framing in decision-making, we investigate whether framing the labour market as insecure increases the willingness of workers to invest in training. We also investigate whether this effect is larger when training contract terms are favourable, such as when training is done mostly in an employer’s time, or when no payback clause is included.Approach: Data are gathered through a vignette-study under a sample of senior Dutch students, with experimental manipulation of frames. Respondents are given a questionnaire in which they are asked to imagine themselves working for a fictitious firm (but presented to them as real). The security/insecurity frames are elicited by randomly stressing either the positive or negative side of a series of events related to the labour market position of people working in this firm. Respondents are then asked to respond to five vignettes, each of these a randomly generated combination of training contract terms. For each vignette, respondents are asked to state whether or not they would be willing to go along with the specified training program under the conditions outlined in that vignette. Data are analysed with multilevel logistic regression. Findings: The willingness to train is not invariably greater under an insecurity frame. Instead, we find a crucial interaction: the willingness to train is greater under an insecurity frame when training-contract terms are favourable (e.g when no payback clause is included), but smaller when training-contract terms are unfavourable. Since the positive and negative effects are approximately equal in size, in a balanced design such as ours they cancel each other out, resulting in a close to zero overall effect for the frame variable.Conclusion: Our results suggest that, when workers are aware of the insecurity in their situation, this only makes them more willing to follow training when the risk of losing their investment is low. 

scholarly journals Negative effects of ant-plant interaction on pollination: costs of a mutualism

Sociobiology ◽  
2021 ◽  
Vol 68 (4) ◽  
pp. e7259
Author(s):  
Rodrigo R Nogueira ◽  
Danilo Ferreira Borges Santos ◽  
Eduardo S Calixto ◽  
Helena Maura Torezan-Silingardi ◽  
Kleber Del-Claro
Keyword(s):  
Indirect Cost ◽  
Experimental Manipulation ◽  
Plant Fitness ◽  
Negative Effects ◽  
Facultative Mutualism ◽  
Plant Parts ◽  
Positive Effects ◽  
Brazilian Savannah ◽  
Artificial Ants ◽  
Negative Impacts

The mutualism of ants and extrafloral nectary (EFN)-bearing plants is known to reduce rates of herbivory. However, ants may have negative impacts on other mutualisms such as pollination, constituting an indirect cost of a facultative mutualism. For instance, when foraging on or close to reproductive plant parts ants might attack pollinators or inhibit their visits. We tested the hypothesis that ants on EFN-bearing plants may negatively influence pollinator behavior, ultimately reducing plant fitness (fruit set). The study was done in a reserve at Brazilian savannah using the EFN-bearing plant Banisteriopsis malifolia (Malpighiaceae). The experimental manipulation was carried out with four groups: control (free visitation of ants), without ants (ant-free branches), artificial ants (isolated branches with artificial ants on flowers) and plastic circles (isolated branches with plastic circles on flowers). We made observations on flower visitors and their interactions, and measured fruit formation as a proxy for plant fitness. Our results showed that pollinators hesitated to visit flowers with artificial ants, negatively affecting pollination, but did not hesitate to visit flowers with plastic circles, suggesting that they recognize the specific morphology of the ants. Pollinators spent more time per flower on the ant-free branches, and the fruiting rate was lower in the group with artificial ants. Our results confirm an indirect cost in this facultative mutualism, where the balance between these negative and positive effects of ants on EFN-bearing plants are not well known.

scholarly journals Positive and negative effects of phoretic mites on the reproductive output of an invasive bark beetle

2010 ◽  
Vol 58 (3) ◽  
pp. 198 ◽  
Author(s):  
Lisa K. Hodgkin ◽  
Mark A. Elgar ◽  
Matthew R. E. Symonds
Keyword(s):  
Beneficial Effect ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Reproductive Output ◽  
Experimental Manipulation ◽  
Life Stages ◽  
Negative Effects ◽  
Ips Grandicollis ◽  
Single Host ◽  
Multiple Species

When multiple species coexist upon a single host, their combined effect on the host can be unpredictable. We explored the effect of phoretic mites on the reproductive output of the five-spined bark beetle, Ips grandicollis. Using correlative approaches and experimental manipulation of mite numbers we examined how mite load affected the number, size and condition of bark beetle offspring produced. We found that mites have both negative and positive consequences on different aspects of bark beetle reproduction. Females from which mites were removed were more fecund and produced larger offspring than females with mites, implying a cost of mite loads. However, when mites were present on females, those bearing the highest mite loads produced offspring that were larger and in better condition, indicating a beneficial effect of mites. These data suggest that phoretic interactions between mites and bark beetles differ over the course of the host’s lifespan, with either the mites interacting in different ways with different life stages of the host (parasitic on adult, mutualistic with larvae), and/or the beetles being host to different mite assemblages over their lifetime.

scholarly journals Revisiting four scientific debates in ocean acidification research

2012 ◽  
Vol 9 (3) ◽  
pp. 893-905 ◽  
Author(s):  
A. J. Andersson ◽  
F. T. Mackenzie
Keyword(s):  
Ocean Acidification ◽  
Shallow Water ◽  
Experimental Manipulation ◽  
Mineral Dissolution ◽  
Negative Effects ◽  
Saturation State ◽  
Seawater Chemistry ◽  
Co2 Gas ◽  
Scientific Investigations ◽  
Scientific Debates

Abstract. In recent years, ocean acidification has gained continuously increasing attention from scientists and a number of stakeholders and has raised serious concerns about its effects on marine organisms and ecosystems. With the increase in interest, funding resources, and the number of scientific investigations focusing on this environmental problem, increasing amounts of data and results have been produced, and a progressively growing and more rigorous understanding of this problem has begun to develop. Nevertheless, there are still a number of scientific debates, and in some cases misconceptions, that keep reoccurring at a number of forums in various contexts. In this article, we revisit four of these topics that we think require further thoughtful consideration including: (1) surface seawater CO2 chemistry in shallow water coastal areas, (2) experimental manipulation of marine systems using CO2 gas or by acid addition, (3) net versus gross calcification and dissolution, and (4) CaCO3 mineral dissolution and seawater buffering. As a summation of these topics, we emphasize that: (1) many coastal environments experience seawater pCO2 that is significantly higher than expected from equilibrium with the atmosphere and is strongly linked to biological processes; (2) addition of acid, base or CO2 gas to seawater can all be useful techniques to manipulate seawater chemistry in ocean acidification experiments; (3) estimates of calcification or CaCO3 dissolution based on present techniques are measuring the net of gross calcification and dissolution; and (4) dissolution of metastable carbonate mineral phases will not produce sufficient alkalinity to buffer the pH and carbonate saturation state of shallow water environments on timescales of decades to hundreds of years to the extent that any potential negative effects on marine calcifiers will be avoided.

Experimental manipulation of water levels in two French riverine grassland soils

2000 ◽  
Vol 21 (1) ◽  
pp. 49-62 ◽  
Author(s):  
Mark van Oorschot ◽  
Nils van Gaalen ◽  
Ed Maltby ◽  
Natalie Mockler ◽  
Andrew Spink ◽  
...  
Keyword(s):  
Experimental Manipulation ◽  
Water Levels ◽  
Grassland Soils

scholarly journals Experimental Manipulation of Beliefs about Uncertainty: Effects on Interpretive Processing and Access to Threat Schemata

2010 ◽  
Vol 1 (1) ◽  
pp. jep.008510 ◽  
Author(s):  
Sonya S. Deschenes ◽  
Michel J. Dugas ◽  
Adam S. Radomsky ◽  
Kristin Buhr
Keyword(s):  
Problem Solving ◽  
Undergraduate Students ◽  
Causal Effect ◽  
Experimental Manipulation ◽  
Group Differences ◽  
Negative Effects ◽  
Experimental Conditions ◽  
Negative Beliefs ◽  
Ease Of Access ◽  
Downward Arrow

This study investigated the influence of beliefs about uncertainty on interpretive biases and access to threat schemata, with the use of an experimental manipulation. Individuals from the community and undergraduate students (N = 74) were randomly assigned to one of two experimental conditions: positive beliefs about uncertainty (n = 37) and negative beliefs about uncertainty (n = 37). To manipulate beliefs about uncertainty, participants watched a presentation on problem solving that either contained information about the positive or the negative effects of uncertainty on problem solving. To assess interpretive biases, participants completed a modified version of the Ambiguous/Unambiguous Situations Diary. Participants read potentially threatening passages and rated their level of worry. Passages were then disambiguated either positively or negatively and participants rated the likelihood and the value (goodness or badness) of these events. To assess access to threat schemata, the Catastrophizing Interview was administered. The Catastrophizing Interview is a structured worry task that assesses various aspects of the worry process, using the downward arrow technique. The results indicated that, although many of the expected group differences were not observed, participants in the negative beliefs about uncertainty group did rate the positively disambiguated scenarios as less positive and the average likelihood of feared consequences to personal worries as more probable. This study provides partial support for the notion that beliefs about uncertainty may have a causal effect on interpretations of ambiguous situations as well as on ease of access to threat schemata.

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