Petiole growth in Ranunculus sceleratus: the role of growth regulators and the leaf blade

1983 ◽  
Vol 61 (12) ◽  
pp. 3326-3331 ◽  
Author(s):  
Ananda B. Samarakoon ◽  
Roger F. Horton
Keyword(s):  
Growth Regulators ◽  
Leaf Blade ◽  
Indoleacetic Acid ◽  
Intact Plants ◽  
Low Levels

In the presence of the leaf blades, excised petioles of the semiaquatic celery-leaved buttercup Ranunculus sceleratus L. elongate when submerged, or when treated in air with indoleacetic acid (IAA), gibberellin A3 (GA3), or C2H4 alone or in combination, responses that are similar to those obtained using intact plants. Isolated petiole sections do not respond to C2H4, but are responsive in the presence of low levels (10−6 mol L−1) IAA. Gibberellin A3 is less active than IAA in promoting growth or in sensitizing the petiole tissue to C2H4.

Social Motives Predict Loneliness During a Developmental Transition

2017 ◽  
Vol 76 (4) ◽  
pp. 145-153 ◽  
Author(s):  
Jana Nikitin ◽  
Alexandra M. Freund
Keyword(s):  
Social Relationships ◽  
Well Being ◽  
Social Avoidance ◽  
Social Approach ◽  
Social Motives ◽  
Developmental Transitions ◽  
Avoidance Motivation ◽  
Negative Effect ◽  
Low Levels

Abstract. Establishing new social relationships is important for mastering developmental transitions in young adulthood. In a 2-year longitudinal study with four measurement occasions (T1: n = 245, T2: n = 96, T3: n = 103, T4: n = 85), we investigated the role of social motives in college students’ mastery of the transition of moving out of the parental home, using loneliness as an indicator of poor adjustment to the transition. Students with strong social approach motivation reported stable and low levels of loneliness. In contrast, students with strong social avoidance motivation reported high levels of loneliness. However, this effect dissipated relatively quickly as most of the young adults adapted to the transition over a period of several weeks. The present study also provides evidence for an interaction between social approach and social avoidance motives: Social approach motives buffered the negative effect on social well-being of social avoidance motives. These results illustrate the importance of social approach and social avoidance motives and their interplay during developmental transitions.

Social and Temporal Comparisons as Moderators of Psychological Resources Associations With Wellbeing

2016 ◽  
Vol 37 (2) ◽  
pp. 96-104 ◽  
Author(s):  
Hasida Ben-Zur
Keyword(s):  
Life Satisfaction ◽  
Positive Affect ◽  
Subjective Wellbeing ◽  
Social Comparisons ◽  
Self Esteem ◽  
Psychological Resources ◽  
Low Levels ◽  
Age Range ◽  
General Wellbeing

Abstract. The current study investigated the associations of psychological resources, social comparisons, and temporal comparisons with general wellbeing. The sample included 142 community participants (47.9% men; age range 23–83 years), who compared themselves with others, and with their younger selves, on eight dimensions (e.g., physical health, resilience). They also completed questionnaires assessing psychological resources of mastery and self-esteem, and three components of subjective wellbeing: life satisfaction and negative and positive affect. The main results showed that high levels of psychological resources contributed to wellbeing, with self-enhancing social and temporal comparisons moderating the effects of resources on certain wellbeing components. Specifically, under low levels of mastery or self-esteem self-enhancing social or temporal comparisons were related to either higher life satisfaction or positive affect. The results highlight the role of resources and comparisons in promoting people’s wellbeing, and suggest that self-enhancing comparisons function as cognitive coping mechanisms when psychological resources are low.

Ups and downs on the roller coaster of task conflict: the role of group cognitive complexity, collective emotional intelligence and team creativity

2020 ◽  
Vol 18 (1) ◽  
pp. 23-37
Author(s):  
Andreea Gheorghe ◽  
Oana Fodor ◽  
Anișoara Pavelea
Keyword(s):  
Emotional Intelligence ◽  
Cognitive Complexity ◽  
Empirical Support ◽  
Task Conflict ◽  
Team Creativity ◽  
Mediating Role ◽  
Low Levels ◽  
Explanatory Mechanism ◽  
The Relationship

This study explores the association between task conflict and team creativity and the role of group cognitive complexity (GCC) as a potential explanatory mechanism in a sample of 159 students organized in 49 groups. Moreover, we analyzed the moderating effect of collective emotional intelligence (CEI)in the relationship between task conflict and GCC.As hypothesized, we found that task conflict has a nonlinear relationship with GCC, but contrary to our expectations, it follows a U-shaped association, not an inversed U-shape. In addition,the moderating role of CEI was significant only at low levels. Contrary to our expectation, the mediating role of GCC did not receive empirical support. Theoretical and practical contributions are discussed.

scholarly journals Parental Warmth, Gratitude, and Prosocial Behavior among Chinese Adolescents: The Moderating Effect of School Climate

2021 ◽  
Vol 18 (13) ◽  
pp. 7033
Author(s):  
Haocheng Luo ◽  
Qingqi Liu ◽  
Chengfu Yu ◽  
Yangang Nie
Keyword(s):  
School Climate ◽  
Prosocial Behavior ◽  
Longitudinal Design ◽  
Positive Association ◽  
Theoretical Explanation ◽  
Parental Warmth ◽  
Physical And Mental Health ◽  
Low Levels ◽  
Moderating Role

Parental warmth plays an important role in the development of adolescents’ physical and mental health. There are numerous empirical studies indicating a relationship between parental warmth and prosocial behavior among adolescents, although the underlying mechanisms of this association remain unclear. Adopting a longitudinal design across two time points, the present study proposes a moderated mediation model to explore the mediating role of gratitude and the moderating role of the school climate between parental warmth and prosocial behavior. The sample consisted of 943 participants (483 boys and 451 girls) who participated in the second assessment and completed questionnaires assessing gratitude, school climate, and prosocial behavior in April 2019. Their parents participated in the first assessment and completed a questionnaire pertaining to parental warmth in October 2018. After controlling for the gender and age of the adolescents, the results showed that the positive association between parental warmth and prosocial behavior is mediated by gratitude, and school climate does play a moderating role in the second half of the mediating path. Specifically, the school climate can play a protective role in adolescents with low levels of gratitude. For adolescents with less gratitude, a strong school climate can promote more prosocial behaviors and can effectively alleviate the negative prediction of low levels of gratitude. This study provides a theoretical explanation for the generation of adolescents’ prosocial behavior and provides theoretical guidance for the interventions of schools and parents.

scholarly journals Low level of plasminogen increases risk for mortality in COVID-19 patients

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
David Della-Morte ◽  
Francesca Pacifici ◽  
Camillo Ricordi ◽  
Renato Massoud ◽  
Valentina Rovella ◽  
...  
Keyword(s):  
Fasting Blood Glucose ◽  
Multidimensional Analysis ◽  
Strongly Correlated ◽  
Analysis Model ◽  
Inflammatory Parameters ◽  
Number Of Patients ◽  
Caucasian Patients ◽  
Low Levels ◽  
Organ Dysfunctions

AbstractThe pathophysiology of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and especially of its complications is still not fully understood. In fact, a very high number of patients with COVID-19 die because of thromboembolic causes. A role of plasminogen, as precursor of fibrinolysis, has been hypothesized. In this study, we aimed to investigate the association between plasminogen levels and COVID-19-related outcomes in a population of 55 infected Caucasian patients (mean age: 69.8 ± 14.3, 41.8% female). Low levels of plasminogen were significantly associated with inflammatory markers (CRP, PCT, and IL-6), markers of coagulation (D-dimer, INR, and APTT), and markers of organ dysfunctions (high fasting blood glucose and decrease in the glomerular filtration rate). A multidimensional analysis model, including the correlation of the expression of coagulation with inflammatory parameters, indicated that plasminogen tended to cluster together with IL-6, hence suggesting a common pathway of activation during disease’s complication. Moreover, low levels of plasminogen strongly correlated with mortality in COVID-19 patients even after multiple adjustments for presence of confounding. These data suggest that plasminogen may play a pivotal role in controlling the complex mechanisms beyond the COVID-19 complications, and may be useful both as biomarker for prognosis and for therapeutic target against this extremely aggressive infection.

scholarly journals Platelet and Erythrocyte Extravasation across Inflamed Corneal Venules Depend on CD18, Neutrophils and Mast Cell Degranulation

2021 ◽  
Vol 22 (14) ◽  
pp. 7360
Author(s):  
Angie De La Cruz ◽  
Aubrey Hargrave ◽  
Sri Magadi ◽  
Justin A. Courson ◽  
Paul T. Landry ◽  
...  
Keyword(s):  
Mast Cell ◽  
Cell Types ◽  
Mast Cell Degranulation ◽  
Wild Type ◽  
Delayed Wound Healing ◽  
Corneal Epithelial ◽  
Corneal Abrasion ◽  
Low Levels ◽  
Endothelial Pores

Platelet extravasation during inflammation is under-appreciated. In wild-type (WT) mice, a central corneal epithelial abrasion initiates neutrophil (PMN) and platelet extravasation from peripheral limbal venules. The same injury in mice expressing low levels of the β2-integrin, CD18 (CD18hypo mice) shows reduced platelet extravasation with PMN extravasation apparently unaffected. To better define the role of CD18 on platelet extravasation, we focused on two relevant cell types expressing CD18: PMNs and mast cells. Following corneal abrasion in WT mice, we observed not only extravasated PMNs and platelets but also extravasated erythrocytes (RBCs). Ultrastructural observations of engorged limbal venules showed platelets and RBCs passing through endothelial pores. In contrast, injured CD18hypo mice showed significantly less venule engorgement and markedly reduced platelet and RBC extravasation; mast cell degranulation was also reduced compared to WT mice. Corneal abrasion in mast cell-deficient (KitW-sh/W-sh) mice showed less venule engorgement, delayed PMN extravasation, reduced platelet and RBC extravasation and delayed wound healing compared to WT mice. Finally, antibody-induced depletion of circulating PMNs prior to corneal abrasion reduced mast cell degranulation, venule engorgement, and extravasation of PMNs, platelets, and RBCs. In summary, in the injured cornea, platelet and RBC extravasation depends on CD18, PMNs, and mast cell degranulation.

Inhibition of cambial activity in Abies balsamea by internal water stress: role of abscisic acid

1975 ◽  
Vol 53 (24) ◽  
pp. 3041-3050 ◽  
Author(s):  
C. H. A. Little
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Indoleacetic Acid ◽  
Stomatal Closure ◽  
Abies Balsamea ◽  
Cambial Activity ◽  
Inhibitory Effect ◽  
Internal Water ◽  
Endogenous Aba

In experiments with attached and detached shoots of balsam fir, Abies balsamea L., synthetic (±)abscisic acid (ABA) (1) reduced photosynthesis and transpiration by inducing stomatal closure, (2) inhibited indoleacetic acid (IAA) - induced cambial activity in photosynthesizing and non-photosynthesizing shoots, and (3) inhibited the basipetal movement of [14C]IAA. Neither gibberellic acid nor kinetin counteracted the inhibitory effect of (±)ABA on IAA-induced cambial activity. In addition it was demonstrated that increasing the internal water stress increased the level of endogenous ABA in the phloem–cambial region of bark peelings and decreased the basipetal movement of [14C]IAA through branch sections. On the basis of these findings it is proposed that internal water stress inhibits cambial activity, partly through increasing the level of ABA; the ABA acts to decrease the provision of carbohydrates and auxin that are required for cambial growth.

scholarly journals Resonance in Optimal Perturbation Evolution. Part II: Effects of a Nonzero Mean PV Gradient

2007 ◽  
Vol 64 (3) ◽  
pp. 695-710 ◽  
Author(s):  
H. de Vries ◽  
J. D. Opsteegh
Keyword(s):  
Potential Vorticity ◽  
Propagation Speed ◽  
Building Blocks ◽  
Joint Effect ◽  
Optimal Perturbation ◽  
Orr Mechanism ◽  
Nonzero Mean ◽  
Low Levels ◽  
Pv Gradient

Abstract Optimal perturbations are constructed for a two-layer β-plane extension of the Eady model. The surface and interior dynamics is interpreted using the concept of potential vorticity building blocks (PVBs), which are zonally wavelike, vertically confined sheets of quasigeostrophic potential vorticity. The results are compared with the Charney model and with the two-layer Eady model without β. The authors focus particularly on the role of the different growth mechanisms in the optimal perturbation evolution. The optimal perturbations are constructed allowing only one PVB, three PVBs, and finally a discrete equivalent of a continuum of PVBs to be present initially. On the f plane only the PVB at the surface and at the tropopause can be amplified. In the presence of β, however, PVBs influence each other’s growth and propagation at all levels. Compared to the two-layer f-plane model, the inclusion of β slightly reduces the surface growth and propagation speed of all optimal perturbations. Responsible for the reduction are the interior PVBs, which are excited by the initial PVB after initialization. Their joint effect is almost as strong as the effect from the excited tropopause PVB, which is also negative at the surface. If the optimal perturbation is composed of more than one PVB, the Orr mechanism dominates the initial amplification in the entire troposphere. At low levels, the interaction between the surface PVB and the interior tropospheric PVBs (in particular those near the critical level) takes over after about half a day, whereas the interaction between the tropopause PVB and the interior PVBs is responsible for the main amplification in the upper troposphere. In all cases in which more than one PVB is used, the growing normal mode configuration is not reached at optimization time.

A Comparison of Synthetic Growth Regulators with Indoleacetic Acid, with Respect to Methionine Metabolism

Weeds ◽  
1965 ◽  
Vol 13 (3) ◽  
pp. 280 ◽  
Author(s):  
Jay D. Mann ◽  
Lowell S. Jordan ◽  
Boysie E. Day
Keyword(s):  
Growth Regulators ◽  
Indoleacetic Acid ◽  
Methionine Metabolism ◽  
Synthetic Growth
Sign in / Sign up

Export Citation Format

Share Document