Acacia holosericea (Fabaceae) litter has allelopathic and physical effects on mission grass (Cenchrus pedicellatus and C. polystachios) (Poaceae) seedling establishment

2014 ◽  
Vol 62 (3) ◽  
pp. 189 ◽  
Author(s):  
Muhammad S. Quddus ◽  
Sean M. Bellairs ◽  
Penelope A. S. Wurm
Keyword(s):  
Root Growth ◽  
Seedling Growth ◽  
Allelopathic Effect ◽  
Negative Effects ◽  
Litter Cover ◽  
Negative Effect ◽  
Acacia Holosericea ◽  
Aqueous Leaf Extract ◽  
Physical Effects

Invasion of grass weeds is a major threat for ecosystems. Mission grass (Cenchrus pedicellatus and C. polystachios) vigorously competes with native vegetation and has become a serious problem in northern Australian savanna. A lower density of mission grass has been observed under the canopy of stands of native Acacia holosericea. We used a series of laboratory and shade house experiments to assess the potential for allelopathy and the role of litter on germination, emergence and seedling growth of these two species of mission grass. Different concentrations of aqueous leaf extract of A. holosericea were used to assess allelopathic effects on germination. Various depths and types of litter were used to investigate the allelopathic and physical effects of litter on emergence and growth of mission grass seedlings in the shade house. Results indicate that extracts did not affect germination of either species of mission grass but root growth of seedlings was affected. Emergence of seedlings in the shade house was affected by physical litter treatments but not by allelopathy. After emergence no negative effects on seedling growth were detected. Overall we found that there was no allelopathic effect on germination and that the negative effect on emergence was due to the physical properties of the litter. This effect on emergence increased with increasing depth of litter. Allelopathy slightly inhibited root growth but once seedlings emerged, litter tended to facilitate growth. This has implications for the ecological management of mission grass on disturbed lands, using strategies such as manipulation of litter cover through Acacia establishment.

The effect of corporate political advocacy on brand perception: an event study analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jan Klostermann ◽  
Chris Hydock ◽  
Reinhold Decker
Keyword(s):  
Event Study ◽  
Design Methodology ◽  
Political Advocacy ◽  
Moderating Effects ◽  
Negative Effects ◽  
Content Type ◽  
The Past ◽  
Negative Effect ◽  
Brand Perception

Purpose In recent years, brands have increasingly engaged in corporate political advocacy (CPA; also termed brand activism or corporate sociopolitical activity) by taking positions on polarizing sociopolitical issues. Recent experimental research suggests that consumers respond to CPA based on its alignment with their own values, and that it typically induces an overall negative response. This study aims to provide additional insights by exploring consumer brand perceptions following CPA. Design/methodology/approach An event study of 106 CPA events and weekly consumer brand perception data was conducted. A regression model was used to investigate the moderating effects of CPA effort, concurrence and the strength of the online protests evoked by the CPA. Findings The results show that CPA had a negative effect on consumers’ brand perceptions and that the effect was stronger for customers relative to non-customers. The negative effect was attenuated by CPA concurrence and amplified by effort. Additionally, online protests were driven by the CPA effort and had a strong negative effect on brand perception. Online protests were stronger in the past, and, in turn, the negative effects of CPA on brand perceptions have slightly weakened in recent years. Originality/value This study contributes to the existing literature by highlighting the role of online protests following CPA and distinguishing consumer and customer responses. This study also provides converging evidence of the moderating effects of effort and concurrence identified in previous studies.

How do followers infer the motives behind an influencer's advertising disclosures?

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Haejoo Han ◽  
Jisu Yi ◽  
Sunghee Jun ◽  
Sungsook Ahn
Keyword(s):  
Process Model ◽  
Purchase Intentions ◽  
Mediation Effect ◽  
Negative Effects ◽  
Anova Analysis ◽  
Content Type ◽  
Mediating Role ◽  
Negative Effect ◽  
Advertising Disclosure

PurposeIn the context of influencer marketing, this study examines the effects of explicit advertising disclosure on consumers' inference regarding influencers' sincere recommendation intent, and its consequences for consumers' purchase intentions.Design/methodology/approachIn Study 1, participants were randomly assigned to the conditions of explicit advertising disclosure (e.g. #AD, #Sponsored) and subtle advertising disclosure (e.g. #ThankYou), and indicated their inference regarding influencers' recommendation motives and their own purchase intentions. One-way ANOVA analysis reveals the effect of advertising disclosure on consumers' purchase intentions and the PROCESS model indicates the mediating role of consumers' inferences regarding influencers' sincere recommendation intent. In Study 2, we implemented a 2 (explicit vs. subtle advertising disclosure) × 2 (moderate vs. large size of followers) between-subjects design, using a two-way ANOVA analysis. We analyzed the moderated mediation effect via the PROCESS model.FindingsConsumers are less inclined to purchase products when influencers express explicit advertising disclosures, compared to when the advertising disclosures are subtle (Study 1). These negative effects of advertising disclosure can be caused by consumers' inferences regarding influencers' sincere recommendation intent in terms of posting content (Studies 1 and 2). Additionally, the negative effect is particularly prominent when an influencer has a large (vs. moderate) number of followers (Study 2).Originality/valueBy examining (1) the effects of explicit advertising disclosure on consumers' inference regarding influencers' persuasion motives and (2) the role of the influencer's number of followers, this research provides both theoretical and practical insights for understanding how best to implement influencer marketing.

Role of nano-biochar in attenuating the allelopathic effect from Imperata cylindrica on rice seedlings

2020 ◽  
Vol 7 (1) ◽  
pp. 116-126 ◽  
Author(s):  
Yu Shen ◽  
Haiyan Tang ◽  
Wenhao Wu ◽  
Heping Shang ◽  
Di Zhang ◽  
...  
Keyword(s):  
Native Species ◽  
Chlorophyll Concentration ◽  
Rice Seedling ◽  
Imperata Cylindrica ◽  
Allelopathic Effect ◽  
Rice Seedlings ◽  
Negative Effects ◽  
Gene Expressions ◽  
Stress Gene

This study applies nano-BC to protect the native species, and reduce the negative effects of rice seedling growth and chlorophyll concentration, as well as oxidative stress, lipid peroxidation and stress gene expressions from invasive species.

scholarly journals Role of exogenous folic acid in alleviation of morphological and anatomical inhibition on salinity-induced stress in barley

2016 ◽  
Vol 11 (4) ◽  
pp. 246 ◽  
Author(s):  
Semra Kilic ◽  
Hatice Tuğba Aca
Keyword(s):  
Folic Acid ◽  
Seedling Growth ◽  
Growth Stages ◽  
Negative Effects ◽  
Salt Treatment ◽  
Yield And Quality ◽  
Agriculture Sustainability ◽  
Vigour Index

Soil salinity is a serious threat to agricultural ecological environment and agriculture sustainability. Ever increasing salinity negatively affects processes such as plant growth and development, ultimately causing diminished economic yield and quality of production, and it might cause a worldwide famine in the future. Thus, helping plants adapt to saline soils and increasing their yield and quality is a must. Our study focused on the enhancing role of exogenously applied folic acid (FA) in mitigation of toxicity caused by salt (NaCl). Barley seeds were pre-treated with 50 <span>µ</span>M FA for 24 h and then exposed to salt. Morphological and anatomical changes in seed germination and seedling growth stages were compared between different treatments of salt in laboratory conditions. Adverse effects of salt in both germination and seedling growth stages depended on the concentration of salt treatment (0.0, 0.25, 0.275, 0.30, 0.325 and 0.35 M). It was shown that the application of FA effectively alleviated the salt-induced inhibition, and reduced the negative effects of salt on germination (germination index and vigour index), seedling growth (radicle and coleoptile lengths, fresh weight) and leaf (stomata and epidermis number, stomatal index, stomata sizes of adaxial and abaxial surfaces) parameters. Moreover, FA elevated all examined parameters of barley also under non-stress conditions. Especially, germination and vigour indices were significantly higher than the control. Our results suggest that exogenous FA is involved in the resistance of barley to salt-stress.

scholarly journals Emotional Exhaustion Among Hotel Employees: The Interactive Effects of Affective Dispositions and Positive Work Reflection

2017 ◽  
Vol 59 (3) ◽  
pp. 285-295 ◽  
Author(s):  
Shi Xu ◽  
Larry R. Martinez ◽  
Hubert Van Hoof ◽  
Mateo Estrella Duran ◽  
Gabriela Maldonado Perez ◽  
...  
Keyword(s):  
Emotional Exhaustion ◽  
Low Cost ◽  
Interactive Effects ◽  
Frontline Employees ◽  
Negative Effects ◽  
Work Lives ◽  
Negative Effect ◽  
Positive Work ◽  
Dispositional Antecedents

Hospitality employees inevitably face emotional exhaustion when performing their jobs. The purpose of this study was to investigate dispositional antecedents of hospitality employees’ emotional exhaustion, including self-instability, pessimism, and affect variability, and how employees’ affect variability mediates the relations between self-instability and pessimism and emotional exhaustion. In addition, we explored the moderating role of positive work reflection on the relation between affect variability and emotional exhaustion. A total of 224 frontline employees in 18 four- and five-star hotels in Ecuador responded to surveys about their emotions and work lives. The findings suggest that (a) emotional exhaustion was influenced by affect variability, (b) affect variability mediated the relations between self-instability and pessimism and emotional exhaustion, and (c) the relation between affect variability and emotional exhaustion was weakened by positive work reflection. The results highlight the importance of potential low-cost and easily trainable interventions that could help in attenuating the negative effects of highly variable emotions and the resulting exhaustion that are prevalent in the hospitality industry. This research is among the first to examine the dispositional antecedents of emotional exhaustion, and the first to highlight the role of positive work reflection as a moderating variable that can buffer the negative effect of affect variability on emotional exhaustion.

scholarly journals Propagation and Possible Allelopathic Effects of Vernoniazeylanica on Selected Bioassay Species

CORD ◽  
2020 ◽  
Vol 36 ◽  
pp. 41-46
Author(s):  
S.H.S. Senarathne ◽  
S. S. Udumann
Keyword(s):  
Seed Germination ◽  
Plant Species ◽  
Seedling Growth ◽  
Contaminated Soil ◽  
Leaf Extract ◽  
Cocos Nucifera ◽  
Test Plant ◽  
Allelopathic Effect ◽  
Aqueous Leaf Extract ◽  
Allelopathic Effects

Vernonia zeylanica (L.) belongs to the family Asteraceae, is one of the major endemic weed species present in coconut (Cocos nucifera L.) plantations of the tropics, which propagates very easily.  There is a possibility that this plant could also possess allelopathic effects, but this has not been scientifically tested.  Thus, a study was carried out to determine the seed germination of V. zeylanica under soil moisture stress conditions, shoot propagation methods and possible allopathic effects of this species, on selected species in bioassay tests.  Germination of V. zeylanica seeds was not observed at higher osmotic potential (-0.9 MPa).  The highest sprouting percentage of this species were obtained with soft wood cuttings.  The aqueous leaf extract was highly phytotoxic, and it significantly reduced germination and seedling growth of all bioassay species tested. Full strength (33.3 g L-1) aqueous extracts of leaves significantly reduced the germination percentage, root and hypocotyl growth rates of all species tested.  The inhibitory effects were often dependent on concentration.  However, the degree of inhibition varied among the test plant species.  The seedling emergences of all four tested plants were severally inhibited when planted in V. zeylanica contaminated soil.  The results indicated that incorporated aqueous leaf extract of V. zeylanica and its rhizosphere contaminated soil can suppress seed germination, seedling growth and seedling emergence of certain plant species indicating a possible allelopathic effect.

scholarly journals Fatigue-Related Effects in the Process of Task Interruption on Working Memory

2021 ◽  
Vol 15 ◽  
Author(s):  
Yueyuan Chen ◽  
Weining Fang ◽  
Beiyuan Guo ◽  
Haifeng Bao
Keyword(s):  
Working Memory ◽  
Cognitive Activity ◽  
Neural Mechanism ◽  
P300 Amplitude ◽  
Negative Effects ◽  
Eeg Data ◽  
Task Interruption ◽  
Negative Effect ◽  
Electrophysiological Effects

Interruption generally has a negative effect on performance by affecting working memory (WM). However, the neural mechanism of interruption has yet to be understood clearly, and previous studies have largely ignored the role of fatigue state. To address these issues, the present study explores the behavioral and electrophysiological effects of interruption on WM performance using electroencephalography (EEG) data. The moderating effect of fatigue is also explored. The participants performed spatial 2-back tasks with math task interruption, suspension interruption, and non-interruption under different fatigue states. The results show that interruption led to increased alpha activity and P300 amplitude, indicating inhibitory control to interference from irrelevant information. Analysis of P200 amplitude revealed that interruption affected attentional reallocation when resuming the primary task. Increased theta power indicated an increased demand for information maintenance during the interruption. A speeding-up effect was discovered after interruption; however, fatigue impaired cognitive ability and further exacerbated the negative effects of interruption on WM and behavioral performance. These findings contribute to a better understanding of cognitive activity during the interruption and of the interaction with fatigue, and provide further support for the theory of memory for goals (MFG).

scholarly journals MANAGING KNOWLEDGE-RELATED BARRIERS TO TECHNOLOGICAL INNOVATION THROUGH EXPLOITATIVE AND EXPLORATIVE ORGANISATIONAL STRATEGIES

2019 ◽  
Vol 23 (04) ◽  
pp. 1950035 ◽  
Author(s):  
NUTTANEEYA (ANN) TORUGSA ◽  
WAYNE O’DONOHUE
Keyword(s):  
Firm Performance ◽  
Technological Innovation ◽  
Hierarchical Regression ◽  
Business Success ◽  
Negative Effects ◽  
Negative Interaction ◽  
Negative Effect ◽  
The Impact ◽  
Workplace Creativity

This study uses data from a sample of 31,948 European innovating firms to examine the impact that knowledge-related barriers to technological innovation have on the link between the level of such innovation and firm performance, and, to investigate the role of “exploitative” and “explorative” organisational strategies in moderating such impact. Exploitative strategies are measured by the level of organisational innovations, and exploratory strategies are measured by the level of methods for fostering workplace creativity. Using moderated hierarchical regression, the results reveal a negative effect of the interaction between technological innovation and related knowledge constraints on firm performance. They also reveal that the negative interaction effect becomes positive at high levels of organisational innovations and creativity-fostering methods. The study findings thus indicate the need for managers of technologically innovative firms to implement both exploitative and explorative organisational strategies. Doing so could help minimise the negative effects of knowledge-related barriers to technological innovation, and in turn promote innovation-based competitiveness and business success.

scholarly journals Fuel exports, aid and terrorism

2017 ◽  
Vol 25 (3) ◽  
pp. 239-267 ◽  
Author(s):  
Simplice Asongu ◽  
Jacinta Nwachukwu
Keyword(s):  
Policy Instrument ◽  
Quantile Regressions ◽  
Negative Effects ◽  
Transnational Terrorism ◽  
Bilateral Aid ◽  
Content Type ◽  
Multilateral Aid ◽  
Negative Effect ◽  
External Flows

Purpose This study aims to use interactive quantile regressions to assess the conditional role of foreign aid in reducing the potentially negative effect of terrorism on fuel exports in 78 developing countries for the period of 1984-2008. Design/methodology/approach Bilateral and multilateral aid indicators have been used, whereas terrorism includes domestic, transnational, unclear and total terrorism dynamics. Interactive quantile regressions have been used. Findings First, with the exception of unclear terrorism, bilateral aid can be used to mitigate the potentially negative effects of terrorism on fuel exports in bottom quantiles of the fuel export distribution. Second, multilateral aid can be used to reduce the negative effect of transnational terrorism on fuel exports exclusively in the highest (90th) quantile of fuel exports. The corresponding modifying thresholds are within policy ranges disclosed in the summary statistics. Practical implications While the policy instrument of bilateral aid is most relevant in countries with below-median fuel exports, the policy instrument of multilateral aid is effective with respect to transnational terrorism in countries with the highest levels of fuel exports. Originality/value This study contributes to the literature on the role of external flows in reducing the negative externalities of terrorism on development outcomes.

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