scholarly journals Parasitism may enhance rather than reduce the predatory impact of an invader

2010 ◽  
Vol 6 (5) ◽  
pp. 636-638 ◽  
Author(s):  
Jaimie T. A. Dick ◽  
Michael Armstrong ◽  
Hazel C. Clarke ◽  
Keith D. Farnsworth ◽  
Melanie J. Hatcher ◽  
...  
Keyword(s):  
Parasite Prevalence ◽  
Reproductive Period ◽  
Enemy Release ◽  
Minor Effect ◽  
Host Feeding ◽  
Feeding Rates ◽  
Functional Responses ◽  
Predatory Impact ◽  
A Minor ◽  
The Impact

Invasive species can have profound impacts on communities and it is increasingly recognized that such effects may be mediated by parasitism. The ‘enemy release’ hypothesis posits that invaders may be successful and have high impacts owing to escape from parasitism. Alternatively, we hypothesize that parasites may increase host feeding rates and hence parasitized invaders may have increased community impacts. Here, we investigate the influence of parasitism on the predatory impact of the invasive freshwater amphipod Gammarus pulex . Up to 70 per cent of individuals are infected with the acanthocephalan parasite Echinorhynchus truttae , but parasitized individuals were no different in body condition to those unparasitized. Parasitized individuals consumed significantly more prey ( Asellus aquaticus ; Isopoda) than did unparasitized individuals. Both parasitized and unparasitized individuals displayed Type-II functional responses (FRs), with the FR for parasitized individuals rising more steeply, with a higher asymptote, compared with unparasitized individuals. While the parasite reduced the fitness of individual females, we predict a minor effect on population recruitment because of low parasite prevalence in the peak reproductive period. The parasite thus has a large per capita effect on predatory rate but a low population fitness effect, and thus may enhance rather than reduce the impact of this invader.

Isothermal Physical Flow Modeling of a Gas Turbine Simple-Cycle Selective-Catalytic-Reduction (SCR) System

2013 ◽  
Author(s):  
Larry Swanson ◽  
Hua Zhang ◽  
Doug Byrd
Keyword(s):  
Selective Catalytic Reduction ◽  
Gas Turbine ◽  
Catalytic Reduction ◽  
Transport Processes ◽  
Simple Cycle ◽  
Minor Effect ◽  
Tracer Injection ◽  
A Minor ◽  
Scr System ◽  
The Impact

A physical flow model of a gas turbine (GT) simple-cycle Selective-Catalytic-Reduction (SCR) system was constructed to a 1/16 geometric scale to validate computational fluid dynamics (CFD) predictions and examine the impact of tempering air injection on system performance. Repeatable velocity contours and tempering air dispersion profiles were developed for baseline (no tempering air), and 12- and 6-lance tempering air injector configurations. The conclusions from the study are: (1) relative to the no lance baseline case, the 12-lance configuration tends to force more of the inlet flow towards the top of the duct, whereas the 6-lance configuration does not affect the upstream profile significantly, (2) adding tempering air does not have a significant impact on the diffuser inlet velocity distribution and has a minor effect on the velocity and dispersion profiles at the NOX-catalyst inlet, (3) at the NOX-catalyst inlet, the 6-lance configuration with tempering air exhibits a slightly skewed flow toward the lower right corner of the duct with a coefficient of variation (COV) of 19.4%, which is slightly better than that for the 12-lance configuration, (4) at the NOX-catalyst inlet, the 12-lance configuration disperses tempering air best because its COV is 20.8% relative to a 27.3% COV for the 6-lance configuration, and (5) a comparison between the local mixing-cup temperature contours for both 12- and 6-lance configurations, based on tracer injection into the tempering air flow, confirms that the CFD model does a good job of qualitatively predicting the heat and mass transport processes in the GT simple-cycle SCR system.

scholarly journals Are suggestions from coupled file changes useful for perfective maintenance tasks?

2017 ◽  
Vol 3 ◽  
pp. e135 ◽  
Author(s):  
Jasmin Ramadani ◽  
Stefan Wagner
Keyword(s):  
Software Maintenance ◽  
Tracking System ◽  
Minor Effect ◽  
New Members ◽  
Team Members ◽  
Using Data ◽  
Time Required ◽  
A Minor ◽  
The Impact ◽  
Important Activity

Background Software maintenance is an important activity in the development process where maintenance team members leave and new members join over time. The identification of files which are changed together frequently has been proposed several times. Yet, existing studies about coupled file changes ignore the feedback from developers as well as the impact of these changes on the performance of maintenance and rather these studies rely on the analysis findings and expert evaluation. Methods We investigate the usefulness of coupled file changes during perfective maintenance tasks when developers are inexperienced in programming or when they were new on the project. Using data mining on software repositories we identify files that are changed most frequently together in the past. We extract coupled file changes from the Git repository of a Java software system and join them with corresponding attributes from the versioning and issue tracking system and the project documentation. We present a controlled experiment involving 36 student participants in which we investigate if coupled file change suggestions influence the correctness of the task solutions and the required time to complete them. Results The results show that the use of coupled file change suggestions significantly increases the correctness of the solutions. However, there is only a minor effect on the time required to complete the perfective maintenance tasks. We also derived a set of the most useful attributes based on the developers’ feedback. Discussion Coupled file changes and a limited number of the proposed attributes are useful for inexperienced developers working on perfective maintenance tasks where although the developers using these suggestions solved more tasks, they still need time to understand and organize this information.

Interspecific interactions between twoTuta absoluta(Lepidoptera: Gelechiidae) larval parasitoids with contrasting life histories

2016 ◽  
Vol 107 (1) ◽  
pp. 32-38 ◽  
Author(s):  
V. Savino ◽  
M.G. Luna ◽  
N.G. Salas Gervassio ◽  
C.E. Coviella
Keyword(s):  
Life Histories ◽  
Interspecific Interactions ◽  
Fixed Time ◽  
Minor Effect ◽  
Host Feeding ◽  
Host Discrimination ◽  
Larval Parasitoids ◽  
Important Pest ◽  
Searching Ability ◽  
A Minor

AbstractInterspecific interactions between two larval parasitoids ofTuta absoluta(Meyrick) with partially overlapping host niches were studied: the idiobiont ectoparasitoidDineulophus phthorimaeaeDe Santis, and the koinobiont endoparasitoidPseudapanteles dignus(Muesebeck).T. absolutais an important pest of tomato crops worldwide, and its management could be improved by understanding the competitive interactions and potential coexistence between these two parasitoids. Firstly, a 15-min fixed time laboratory test evaluated the host-searching ability of adultD. phthorimaeaeandP. dignuswasps onT. absolutalarvae. Secondly,D. phthorimaeaehost discrimination against endoparasitized and non-endoparasitized hosts byP. dignus, at different adult female ages, was experimentally examined.D. phthorimaeaewasps spent significantly more time in general searching in the presence of its competitor than in its absence, but, parasitism was only effective byP. dignus. OlderD. phthorimaeaewasps discriminated significantly less than young wasps betweenT. absolutalarvae parasitized and unparasitized byP. dignus, and an interaction took place by non-concurrent host-feeding. Intra-guild predation ofP. dignuslarvae byD. phthorimaeaefemale feeding behaviour might have a minor effect in this system. Results are discussed in the context of literature supporting diverse evidence of coexistence in other parasitoid-host systems, with implications forT. absolutabiological control.

scholarly journals Differential effects of corticosteroids and anti-TNF on tumor-specific immune responses - implications for the management of irAEs

2018 ◽  
Author(s):  
Arianna Draghi ◽  
Troels Holz Borch ◽  
Haja Dominike Radic ◽  
Christopher Aled Chamberlain ◽  
Aishwarya Gokuldass ◽  
...  
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Tumor Infiltrating Lymphocytes ◽  
High Dose ◽  
Minor Effect ◽  
Tumor Killing ◽  
High Doses ◽  
A Minor ◽  
The Impact

AbstractUp to 60% of patients treated with cancer immunotherapy develop severe or life threatening immune-related adverse events (irAEs). Immunosuppression with high doses of corticosteroids or, in refractory cases, with tumor necrosis factor (TNF) antagonists, are the mainstay of treatment for irAEs. It is currently unknown what is the impact of corticosteroids and anti-TNF on the activity of antitumor T cells. In this study, the influences of clinically relevant doses of dexamethasone (corresponding to an oral dose of 10 to 125 mg prednisolone) and infliximab (anti-TNF) on the activation and killing ability of tumor-infiltrating lymphocytes (TILs) was tested in vitro. Overall, dexamethasone at low or intermediate/high dose impaired the activation (respectively −46% and −62%) and tumor-killing ability (respectively −48% and −53%) of tumor-specific TILs. In contrast, a standard clinical dose of infliximab only had a minor effect on T cell activation (−20%) and tumor killing (−10%). A brief resting following exposure to dexamethasone was sufficient to rescue the in vitro activity of TILs. In conclusion, clinically-relevant doses of infliximab only influenced to a lesser extent the activity of tumor-specific TILs in vitro, whereas even low doses of corticosteroids markedly impaired the antitumor activity of TILs. These data support steroid-sparing strategies and early initiation of anti-TNF for the treatment of irAEs in immuno-oncology.

A Discussion of Iron Golf Club Head Inertia Tensors and Their Effects on the Golfer

1996 ◽  
Vol 12 (4) ◽  
pp. 449-469 ◽  
Author(s):  
Steven M. Nesbit ◽  
Terry A. Hartzell ◽  
John C. Nalevanko ◽  
Ryan M. Starr ◽  
Mathew G. White ◽  
...  
Keyword(s):  
Major Effect ◽  
Golf Swing ◽  
Golf Club ◽  
Minor Effect ◽  
Impact Function ◽  
Club Head ◽  
A Minor ◽  
The Impact ◽  
Flexible Model ◽  
Eccentric Impact

This paper discusses the inertia tensors of iron golf club heads and their influence on the swing of a golfer and the behavior of the golf club. Inertia tensors of various five-iron club head configurations were determined using solid modeling and were compared with equivalent solid ellipsoids. A golf swing and club behavior analysis was performed using a computer model comprised of a 3D parametric flexible model of a golf club driven with data from a recorded golf swing, and an impact function. The impact results were verified experimentally. The analysis without impact determined that altering club head inertia had a minor effect on the torque required to swing the club and the deflections of the club head at the time of impact. The analysis with an eccentric impact found that altering club head inertia had a major effect on transmitted forces and torques and a moderate effect on deflection of the club head.

The Outcomes of Student Protest

2020 ◽  
pp. 129-170
Author(s):  
Donatella della Porta ◽  
Lorenzo Cini ◽  
César Guzmán-Concha
Keyword(s):  
Trade Unions ◽  
Minor Effect ◽  
Education Policies ◽  
Student Protests ◽  
Political Actors ◽  
Higher Education Policies ◽  
The Government ◽  
A Minor ◽  
Student Demands ◽  
The Impact

This chapter evaluates the impact of student protests in the four regions on higher education policies. The four cases differ in the degree to which students were able to achieve concessions close to their demands. In both Chile and Quebec, as student demands were supported by significant social constituencies and the government proved unable to appease the protests, the opposition parties presented themselves as allies. These parties committed themselves to delivering reforms that would (partially) meet student demands, while students attempted to gain influence in decision-making bodies by joining political parties and/or participating in elections. By contrast, in England and Italy, students did not obtain concessions from the government, while their campaigns had a minor effect on public opinion, which remained relatively indifferent to their demands. More notably, student protesters failed to build solid alliances with other social and political actors opposing similar neoliberal measures in other fields of policy, such as trade unions, radical left parties, and social movements.

What causes financial crisis in Asian countries?

2018 ◽  
pp. 5-19 ◽  
Author(s):  
Anh Thi Thuy Vo ◽  
Thuy Xuan Ha ◽  
Khanh Phan Nha Bui
Keyword(s):  
Corporate Governance ◽  
Financial Crisis ◽  
Minor Effect ◽  
Asian Countries ◽  
Macroeconomic Factors ◽  
Governance Index ◽  
The Business Cycle ◽  
A Minor ◽  
And Control ◽  
The Impact

In this paper, we investigate the indicators of financial crisis in Asian countries, focusing more on the impact of corporate governance. Unlike the previous studies such as Johnson et al. (2000) and Acemoglu et al. (2003) that use some fixed measures of corporate governance based on the law in force in a specific year—such as the anti-director right index (ADRI) or the anti-self dealing index (ASDI)—we employ the annual Worldwide Governance Index (WGIs) and the Quality of Governance Index. The regression results, which use the data of 19 Asian countries from 1996 to 2015, and control for country fixed effect and the business cycle, show that the macroeconomic factors appear to have no effect, or a minor effect, on currency depreciation. However, better corporate governance reduces the decline in currency value.

scholarly journals Biological Traits of the Pincer Wasp Gonatopus flavifemur (Esaki & Hashimoto) Associated with Different Stages of Its Host, the Brown Planthopper, Nilaparvata lugens (Stål)

Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 279
Author(s):  
Jiachun He ◽  
Yuting He ◽  
Fengxiang Lai ◽  
Xiangsheng Chen ◽  
Qiang Fu
Keyword(s):  
Brown Planthopper ◽  
Female Offspring ◽  
Nilaparvata Lugens ◽  
Biological Traits ◽  
Host Feeding ◽  
Feeding Rates ◽  
Functional Responses ◽  
Male Adult ◽  
Offspring Development ◽  
Nilaparvata Lugens Stål

Gonatopus flavifemur (Esaki & Hashimoto) is a common parasitoid of the most important rice pest, the brown planthopper (BPH) Nilaparvata lugens (Stål), in eastern and southeastern Asia. We investigated the parasitism rates, feeding rates, and offspring development of G. flavifemur in association with five instars of BPH nymphs and male and female adults under laboratory conditions (27 ± 1 °C and 70 ± 5% Relative Humidity). The results showed that the life stage of the host significantly affects parasitism, host feeding, and offspring development by G. flavifemur. The parasitism rate was highest on 4th instar nymphs, and the feeding rate was highest on 1st instar nymphs. The cocooning rate on male adult BPHs was significantly lower than that on other stages; however, emergence rates did not significantly differ among the BPH stages. The rate of female offspring upon emergence from 5th instars was higher than other stages. Both the parasitism and host-feeding functional responses of G. flavifemur to different BPH stages fit well with Holling type II models, supporting the results of parasitism and feeding rates and indicating that G. flavifemur would be a good agent for BPH control. In conclusion, G. flavifemur prefers to feed on young nymphs but prefers to parasitize older nymphs. In addition, 5th instar nymphs are favorable to female offspring of the pincer wasp.

scholarly journals Warming mediates intraspecific multiple predator effects from an invasive crustacean

2021 ◽  
Vol 168 (3) ◽  
Author(s):  
Ross N. Cuthbert ◽  
Ryan J. Wasserman ◽  
Tatenda Dalu ◽  
Elizabeta Briski
Keyword(s):  
Alien Species ◽  
Trophic Interactions ◽  
Invasive Alien Species ◽  
Ecological Impacts ◽  
Feeding Rates ◽  
Functional Responses ◽  
Multiple Predator Effects ◽  
Predator Interactions ◽  
The Impact ◽  
Predator Effects

AbstractInvasive alien species impacts might be mediated by environmental factors such as climatic warming. For invasive predators, multiple predator interactions could also exacerbate or dampen ecological impacts. These effects may be especially pronounced in highly diverse coastal ecosystems that are prone to profound and rapid regime shifts. We examine emergent effects of warming on the strength of intraspecific multiple predator effects from a highly successful invasive gammarid Gammarus tigrinus, using a functional response approach towards larval chironomids (feeding rates under different prey densities). Single predator maximum feeding rates were three-times higher at 24 °C compared to 18 °C overall, with potentially prey destabilising type II functional responses exhibited. However, pairs of gammarids exhibited intraspecific multiple predator effects that were in turn mediated by temperature regime, whereby synergisms were found at the lower temperature (i.e. positive non-trophic interactions) and antagonisms detected at the higher temperature (i.e. negative non-trophic interactions) under high prey densities. Accordingly, warming scenarios may worsen the impact of this invasive alien species, yet implications of temperature change are dependent on predator–predator interactions. Emergent effects between abiotic and biotic factors should be considered in ecological impact predictions across habitat types for invasive alien species.

Star formation history and dynamical evolution of the solar neighbourhood

2018 ◽  
Vol 14 (S344) ◽  
pp. 90-93
Author(s):  
Andreas Just ◽  
Reza Moetazedian ◽  
Evgeny Polyachenko
Keyword(s):  
Star Formation ◽  
Dynamical Evolution ◽  
Star Formation History ◽  
Minor Effect ◽  
Thin Disc ◽  
Formation History ◽  
Satellite Galaxies ◽  
A Minor ◽  
The Impact ◽  
Bar Formation

AbstractBased on cosmological re-simulations we have shown that the impact of satellite galaxies has a minor effect on the thin disc heating. In contrast satellite galaxies can generate long-lived warps of the outer disc and they can advance or delay bar formation significantly.

Sign in / Sign up

Export Citation Format

Share Document