scholarly journals Allelopathic Mechanisms in Fire-Prone Ecosystems

Author(s):  
Nursema Aktepe ◽  
Ömer Küçük

Understanding the fire-prone arid-zone pine species and maquis vegetation's response to fire is very important to reveal the ecology and evolution of these species. During the succession of vegetation, there are complex relationships between allelopathic metabolites and fires. Many plant communities such as pines, maquis, savannas and woodlands are known to play a critical role in the development of succession. However, studies revealing the relationship between succession processes and allelopathic mechanisms in fire-prone ecosystems are quite limited. Most evergreen maquis vegetations are one of the most studied fire ecosystems. In maquis vegetation, fire causes the formation of plant communities that continue with allelochemicals produced by plants, as well as shaping the climate of the region. The event of a living species inhibiting another species by secreting toxic compounds is expressed as allelopathy. These toxic compounds are generally referred to as allelochemicals. Many maquis species that grow in fire-prone ecosystems excrete their allelochemicals, preventing the development of herbaceous species around them and invade their habitats. These chemicals, which accumulate in the soil during the dry season, affect the succession processes in vegetation in the event of a fire and determine which species will follow each other. Considering these relationships, it can be said that allelopathic plants have the potential to change plant diversity in vegetation by changing their functional plant characteristics. The purpose of this review is to determine the relationship between allelochemicals and fire of plant species in fire-prone ecosystems, and to reveal how this affects the succession processes.

2020 ◽  
Vol 26 ◽  
Author(s):  
Yujie Shen ◽  
Yexiang Lin ◽  
Kai Liu ◽  
Jinlan Chen ◽  
Juanjuan Zhong ◽  
...  

Background: A number of studies have proposed that lncRNA XIST plays a role in the development and chemosensitivity of NSCLC. Besides, XIST may become a potential therapeutic target for NSCLC patients. The aim of this review is to reveal the biological functions and exact mechanisms of XIST in NSCLC. Methods: In this review, relevant researches involving in the relationship between XIST and NSCLC are collected through systematic retrieval of PubMed Results: XIST is an oncogene in NSCLC and is abnormally upregulated in NSCLC tissues. Considerable evidence has shown that XIST exerts a critical role in the proliferation, invasion, migration, apoptosis and chemosensitivity of NSCLC cells. XIST mainly functions as a ceRNA in NSCLC process, while XIST also functions at transcriptional levels. Conclusion: LncRNA XIST has potential to become a novel biomolecular marker of NSCLC and a therapeutic target for NSCLC.


Author(s):  
Cordelia Estevez-Casellas ◽  
Mª Dolores Gómez-Medina ◽  
Esther Sitges

Emotional intelligence plays a critical role in adolescence since it involves a change towards psychological, social, and sexual maturity; a stage in which the foundations of intimate social relationships are established. Emotional competences regulate the quality of these relationships in adolescence and can provide protection against or facilitate the use of violence within them. Based on the above, this study aims to analyze the relationship between emotional intelligence and violence exercised, received, and perceived by adolescents in dating relationships. A sample of 254 subjects (43.1% men and 56.9% women) between 12 and 18 years old was analyzed through the Emotional Intelligence Questionnaires of BarOn ICE:NA and Violence Exercised Perceived and Received by Adolescents VERA. The results of the research have shown that there is a significant and inverse relation between the dimensions of emotional intelligence and the violence exercised by adolescents in their dating relationships, and a positive and significant relation between emotional intelligence and the perception of violent behavior. For this reason, the importance of educating people about emotional intelligence from childhood within both the academic and family sphere is highlighted. This is fundamental to preventing the appearance of such violent behaviors and promoting an adequate adaptation to the environment.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hao-Nan Guo ◽  
Li-Xia Wang ◽  
Hong-Tao Liu

Abstract This study aims to investigate the relationship between key physicochemical parameters related to composting process and bioavailability of Cd, As and Cr during swine manure composting through regulating different initial carbon to nitrogen (C/N) ratios (15:1, 20:1, 25:1) and bulking agent types (straw, green waste). Results showed that higher initial C/N ratio of 20:1 or 25:1 and straw as bulking agent were optimal to reduce the bioavailability of Cd, As and Cr (62.4%, 20.6% and 32.2% reduction, respectively). Redundancy analysis implied that the bioavailability of Cd was significantly associated with total phosphorus and total nitrogen, deducing the formation of phosphate precipitation and biosorption might participated in the reaction process, while that of As and Cr were mainly influenced by organic matter (OM), cation exchange capacity (CEC) and OM, CEC, electric conductivity, respectively. A total of 48.5%, 64.6% and 62.2% of Cd, As and Cr redistribution information could be explained by the above parameters. Further correlation analysis revealed that bioavailable As and Cr were negatively correlated with humic acid to fulvic acid ratio. In summary, this study confirms that the mechanisms of phosphate precipitation, biosorption and humification played critical role in reducing Cd, As and Cr bioavailability during swine manure composting.


2019 ◽  
pp. 135910531986997 ◽  
Author(s):  
Huazhan Yin ◽  
Li Zhang ◽  
Dan Li ◽  
Lu Xiao ◽  
Mei Cheng

This study investigated the neuroanatomical basis of the association between depression/anxiety and sleep quality among 370 college students. The results showed that there was a significant correlation between sleep quality and depression/anxiety. Moreover, mediation results showed that the gray matter volume of the right insula mediated the relationship between depression/anxiety and sleep quality, which suggested that depression/anxiety may affect sleep quality through the right insula volume. These findings confirmed a strong link between sleep quality and depression/anxiety, while highlighting the volumetric variation in the right insula associated with emotional processing, which may play a critical role in improving sleep quality.


2005 ◽  
Vol 288 (5) ◽  
pp. R1396-R1410 ◽  
Author(s):  
Shaun W. Phillips ◽  
Gerard L. Gebber ◽  
Susan M. Barman

We used spectral analysis and event-triggered averaging to determine the effects of chemical inactivation of the medullary lateral tegmental field (LTF) on 1) the relationship of intratracheal pressure (ITP, an index of vagal lung inflation afferent activity) to sympathetic nerve discharge (SND) and phrenic nerve activity (PNA) and 2) central respiratory rate in paralyzed, artificially ventilated dial-urethane-anesthetized cats. ITP-SND coherence value at the frequency of artificial ventilation was significantly ( P < 0.05; n = 18) reduced from 0.73 ± 0.04 (mean ± SE) to 0.24 ± 0.04 after bilateral microinjection of muscimol into the LTF. Central respiratory rate was unexpectedly increased in 12 of these experiments (0.28 ± 0.03 vs. 0.95 ± 0.25 Hz). The ITP-PNA coherence value was variably affected by chemical inactivation of the LTF. It was unchanged when central respiratory rate was also not altered, decreased when respiratory rate was increased above the rate of artificial ventilation, and increased when respiratory rate was raised from a value below the rate of artificial ventilation to the same frequency as the ventilator. Chemical inactivation of the LTF increased central respiratory rate in four of six vagotomized cats but did not significantly affect the PNA-SND coherence value. These data demonstrate that the LTF 1) plays a critical role in mediating the effects of vagal lung inflation afferents on SND but not PNA, 2) helps maintain central respiratory rate in the physiological range, but 3) is not involved in the coupling of central respiratory and sympathetic circuits.


2021 ◽  
pp. 082957352110347
Author(s):  
Luis Francisco Vargas-Madriz ◽  
Chiaki Konishi

Canada’s high school graduation rates are still low when compared to other members of the OECD. Previous studies have found academic involvement is associated with positive trajectories toward graduation, that social support promotes student engagement, and that school belonging could mediate this relationship. Still, little is known about the specificity of such mediation, especially in Québec. Therefore, this study examined the role of belonging as mediator of the relationship between social support and academic involvement. Participants ( N = 238) were high-school students from the Greater Montréal Area. All variables were measured by the School-Climate Questionnaire. Results from hierarchical multiple regressions indicated parental support had a direct relationship, whereas peer and teacher support had a mediated relationship by school belonging with academic involvement. Results highlight the critical role of school belonging in promoting academic involvement in relation to social support.


2012 ◽  
Vol 11 (6) ◽  
pp. 820-826 ◽  
Author(s):  
Laura H. Okagaki ◽  
Kirsten Nielsen

ABSTRACTThe human fungal pathogenCryptococcus neoformansproduces an enlarged “titan” cell morphology when exposed to the host pulmonary environment. Titan cells exhibit traits that promote survival in the host. Previous studies showed that titan cells are not phagocytosed and that increased titan cell production in the lungs results in reduced phagocytosis of cryptococcal cells by host immune cells. Here, the effect of titan cell production on host-pathogen interactions during early stages of pulmonary cryptococcosis was explored. The relationship between titan cell production and phagocytosis was found to be nonlinear; moderate increases in titan cell production resulted in profound decreases in phagocytosis, with significant differences occurring within the first 24 h of the infection. Not only were titan cells themselves protected from phagocytosis, but titan cell formation also conferred protection from phagocytosis to normal-size cryptococcal cells. Large particles introduced into the lungs were not phagocytosed, suggesting the large size of titan cells protects against phagocytosis. The presence of large particles was unable to protect smaller particles from phagocytosis, revealing that titan cell size alone is not sufficient to provide the observed cross-protection of normal-size cryptococcal cells. These data suggest that titan cells play a critical role in establishment of the pulmonary infection by promoting the survival of the entire population of cryptococcal cells.


2015 ◽  
Vol 645-646 ◽  
pp. 70-74 ◽  
Author(s):  
Min Zhong ◽  
Yu Hang Zhao ◽  
Shou Mian Chen ◽  
Ming Li ◽  
Shao Hai Zeng ◽  
...  

An embedded SiGe layer was applied in the source/drain areas (S/D) of a field-effect transistor to boost the performance in the p channels. Raised SiGe S/D plays a critical role in strain engineering. In this study, the relationship between the SiGe overfilling and the enhancement of channel stress was investigated. Systematic technology computer aided design (TCAD) simulations of the SiGe overfill height in a 40 nm PMOS were performed. The simulation results indicate that a moderate SiGe overfilling induces the highest stress in the channel. Corresponding epitaxial growth experiments were done and the obtained experimental data was in good agreement with the simulation results. The effect of the SiGe overfilling is briefly discussed. The results and conclusions presented within this paper might serve as useful references for the optimization of the embedded SiGe stressor for 40 nm logic technology node and beyond.


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