scholarly journals Insight Into Late Wilting Disease of Cucumber Demonstrates the Complexity of the Phenomenon in Fluctuating Environments

Plant Disease ◽  
2019 ◽  
Vol 103 (11) ◽  
pp. 2877-2883 ◽  
Author(s):  
Amit M. Philosoph ◽  
Aviv Dombrovsky ◽  
Yigal Elad ◽  
Amnon Koren ◽  
Omer Frenkel
Keyword(s):  
Environmental Conditions ◽  
Middle Eastern ◽  
Climatic Conditions ◽  
Pythium Species ◽  
Ongoing Research ◽  
Mortality Incidence ◽  
Low Levels ◽  
Combined Infection ◽  
Insight Into

Some diseases are caused by coinfection of several pathogens in the same plant. However, studies on the complexity of these coinfection events under different environmental conditions are scarce. Our ongoing research involves late wilting disease of cucumber caused by coinfection of Cucumber green mottle mosaic virus (CGMMV) and Pythium spp. We specifically investigated the role of various temperatures (18, 25, 32°C) on the coinfection by CGMMV and two predominant Pythium species occurring in cucumber greenhouses under Middle Eastern climatic conditions. During the summer months, Pythium aphanidermatum was most common, whereas P. spinosum predominated during the winter–spring period. P. aphanidermatum preferred higher temperatures while P. spinosum preferred low temperatures and caused very low levels of disease at 32°C when the 6-day-old seedlings were infected with P. spinosum alone. Nevertheless, after applying a later coinfection with CGMMV on the 14-day-old plants, a synergistic effect was detected for both Pythium species at optimal and suboptimal temperatures, with P. spinosum causing high mortality incidence even at 32°C. The symptoms caused by CGMMV infection appeared earlier as the temperature increased. However, within each temperature, no significant influence of the combined infection was detected. Our results demonstrate the complexity of coinfection in changing environmental conditions and indicate its involvement in disease development and severity as compared with infection by each of the pathogens alone.

scholarly journals Plant adaptation to temperature and photoperiod

1996 ◽  
Vol 5 (3) ◽  
pp. 251-260 ◽  
Author(s):  
Olavi Junttila
Keyword(s):  
Environmental Conditions ◽  
Growth Cycle ◽  
Climatic Conditions ◽  
Annual Growth ◽  
Annual Plants ◽  
Plant Adaptation ◽  
Timing Of Reproduction ◽  
Growth Capacity ◽  
Climatic Adaptation

Plants respond to environmental conditions both by adaptation and by acclimation. The ability of the plants to grow, reproduce and survive under changing climatic conditions depends on the efficiency of adaptation and acclimation. The adaptation of developmental processes in plants to temperature and photoperiod is briefly reviewed. In annual plants this adaptation is related to growth capacity and to the timing of reproduction. In perennial plants growing under northern conditions, adaptation of the annual growth cycle to the local climatic cycle is of primary importance. Examples of the role of photothermal conditions in regulation of these phenological processes are given and discussed. The genetic and physiological bases for climatic adaptation in plants are briefly examined.

scholarly journals Determinants of Marital Fertility in Pakistan: An Application of the "Synthesis Framework"

1993 ◽  
Vol 32 (2) ◽  
pp. 199-220 ◽  
Author(s):  
Mohammed Sabihuddin Buti ◽  
Aroon Jamal
Keyword(s):  
Demographic Transition ◽  
Marital Fertility ◽  
Labour Force ◽  
Fertility Control ◽  
Natural Fertility ◽  
Low Levels ◽  
And Migration ◽  
Insight Into

The fertility phase of the demographic transition has increasingly been viewed as a movement from high to low levels of fertility, and as a shift from natural fertility to deliberately controlled fertility. In an attempt to gain more insight into this process, the present study, in the context of Pakistan, is based on intensive National Population, Labour Force, and Migration Survey data covering 10,000 households. It aims to focus on the determinants of fertility in Pakistan, specifically the determinants of the adoption of deliberate fertility regulations. The role of socia-economic modernisation and cultural factors in the determination of the potential family size and the adoption of deliberate fertility control through a knowledge of fertility regulations have also been explored. The 'Synthesis Framework' of fertility determination, applied to Sri Lanka and Colombia by Easterlin and Crimmins (1982), and with its recent modifications by Ahmed (1987), is the main vehicle for the study.

scholarly journals Idealised simulations of cyclones with robust symmetrically unstable sting jets

2020 ◽  
Vol 1 (1) ◽  
pp. 63-91 ◽  
Author(s):  
Ambrogio Volonté ◽  
Peter A. Clark ◽  
Suzanne L. Gray
Keyword(s):  
Conceptual Model ◽  
Environmental Conditions ◽  
Positive Relationship ◽  
Initial State ◽  
Sensitivity Experiments ◽  
Fracture Region ◽  
Wide Range ◽  
Peak Speed ◽  
Insight Into

Abstract. Idealised simulations of Shapiro–Keyser cyclones developing a sting jet (SJ) are presented. Thanks to an improved and accurate implementation of thermal wind balance in the initial state, it was possible to use more realistic environments than in previous idealised studies. As a consequence, this study provides further insight into SJ evolution and dynamics and explores SJ robustness to different environmental conditions, assessed via a wide range of sensitivity experiments. The control simulation contains a cyclone that fits the Shapiro–Keyser conceptual model and develops a SJ whose dynamics are associated with the evolution of mesoscale instabilities along the airstream, including symmetric instability (SI). The SJ undergoes a strong descent while leaving the cloud-head banded tip and markedly accelerating towards the frontal-fracture region, revealed as an area of buckling of the already-sloped moist isentropes. Dry instabilities, generated by vorticity tilting via slantwise frontal motions in the cloud head, exist in similar proportions to moist instabilities at the start of the SJ descent and are then released along the SJ. The observed evolution supports the role of SI in the airstream’s dynamics proposed in a conceptual model outlined in a previous study. Sensitivity experiments illustrate that the SJ is a robust feature of intense Shapiro–Keyser cyclones, highlighting a range of different environmental conditions in which SI contributes to the evolution of this airstream, conditional on the model having adequate resolution. The results reveal that several environmental factors can modulate the strength of the SJ. However, a positive relationship between the strength of the SJ, both in terms of peak speed and amount of descent, and the amount of instability occurring along it can still be identified. In summary, the idealised simulations presented in this study show the robustness of SJ occurrence in intense Shapiro–Keyser cyclones and support and clarify the role of dry instabilities in SJ dynamics.

scholarly journals Zeaxanthin, a Molecule for Photoprotection in Many Different Environments

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5825
Author(s):  
Barbara Demmig-Adams ◽  
Jared J. Stewart ◽  
Marina López-Pozo ◽  
Stephanie K. Polutchko ◽  
William W. Adams
Keyword(s):  
Genetic Variation ◽  
Environmental Factors ◽  
Excitation Energy ◽  
Environmental Conditions ◽  
Xanthophyll Cycle ◽  
Field Studies ◽  
Photosynthetic Productivity ◽  
High Degree ◽  
Insight Into

Conversion of sunlight into photochemistry depends on photoprotective processes that allow safe use of sunlight over a broad range of environmental conditions. This review focuses on the ubiquity of photoprotection associated with a group of interconvertible leaf carotenoids, the xanthophyll cycle. We survey the striking plasticity of this process observed in nature with respect to (1) xanthophyll cycle pool size, (2) degree and speed of interconversion of its components, and (3) flexibility in the association between xanthophyll cycle conversion state and photoprotective dissipation of excess excitation energy. It is concluded that the components of this system can be independently tuned with a high degree of flexibility to produce a fit for different environments with various combinations of light, temperature, and other factors. In addition, the role of genetic variation is apparent from variation in the response of different species growing side-by-side in the same environment. These findings illustrate how field studies can generate insight into the adjustable levers that allow xanthophyll cycle-associated photoprotection to support plant photosynthetic productivity and survival in environments with unique combinations of environmental factors.

scholarly journals Effect of the presence of moisture at the wheel–rail interface during dew and damp conditions

2017 ◽  
Vol 232 (4) ◽  
pp. 979-989 ◽  
Author(s):  
BT White ◽  
R Nilsson ◽  
U Olofsson ◽  
AD Arnall ◽  
MD Evans ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Weather Conditions ◽  
Local Scale ◽  
Weather Data ◽  
Friction Modifiers ◽  
Precipitation Temperature ◽  
Rail Industry ◽  
Low Levels ◽  
Local Weather ◽  
Insight Into

Incidents involving low levels of adhesion between the wheel and rail are a recurrent issue in the rail industry. The problem has been mitigated using friction modifiers and traction enhancers, but a significant number of incidents still occur throughout the year. This study looks at the environmental conditions that surround periods of low adhesion in order to provide an insight into why low adhesion events occur. Network Rail Autumn data, which provided details on the time and location of low adhesion incidents, were compared against weather data on a national and then local scale. Low adhesion incidents have often been attributed to contamination on the rails, such as organic leaf matter, but these incidents also occur when no contamination is visible. The time, date and location of incidents were linked to local weather data to establish any specific weather conditions that could lead to these events. The effects of precipitation, temperature and humidity on rails were analysed in order to further the understanding of low adhesion in the wheel–rail contact, which will lead to adopting better methods of mitigating this problem.

scholarly journals New Insight into the Role of the PhaP Phasin of Ralstonia eutropha in Promoting Synthesis of Polyhydroxybutyrate

2001 ◽  
Vol 183 (7) ◽  
pp. 2394-2397 ◽  
Author(s):  
Gregory M. York ◽  
JoAnne Stubbe ◽  
Anthony J. Sinskey
Keyword(s):  
Ralstonia Eutropha ◽  
Volume Ratio ◽  
Growth Conditions ◽  
Deletion Strain ◽  
Granule Formation ◽  
Phb Production ◽  
Polyhydroxyalkanoate Synthase ◽  
Low Levels ◽  
Insight Into

ABSTRACT Phasins are proteins that are proposed to play important roles in polyhydroxyalkanoate synthesis and granule formation. Here the phasin PhaP of Ralstonia eutropha has been analyzed with regard to its role in the synthesis of polyhydroxybutyrate (PHB). Purified recombinant PhaP, antibodies against PhaP, and an R. eutropha phaP deletion strain have been generated for this analysis. Studies with the phaP deletion strain show that PhaP must accumulate to high levels in order to play its normal role in PHB synthesis and that the accumulation of PhaP to low levels is functionally equivalent to the absence of PhaP. PhaP positively affects PHB synthesis under growth conditions which promote production of PHB to low, intermediate, or high levels. The levels of PhaP generally parallel levels of PHB in cells. The results are consistent with models whereby PhaP promotes PHB synthesis by regulating the surface/volume ratio of PHB granules or by interacting with polyhydroxyalkanoate synthase and indicate that PhaP plays an important role in PHB synthesis from the early stages in PHB production and across a range of growth conditions.

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.

Plasminogen Activation In Vivo upon Intravenous Infusion of DDAVP

1992 ◽  
Vol 67 (01) ◽  
pp. 111-116 ◽  
Author(s):  
Marcel Levi ◽  
Jan Paul de Boer ◽  
Dorina Roem ◽  
Jan Wouter ten Cate ◽  
C Erik Hack
Keyword(s):  
Monoclonal Antibodies ◽  
Plasminogen Activator ◽  
Plasma Levels ◽  
Fold Increase ◽  
Fibrinolytic System ◽  
Plasminogen Activation ◽  
Plasminogen Activator Activity ◽  
Insight Into

SummaryInfusion of desamino-d-arginine vasopressin (DDAVP) results in an increase in plasma plasminogen activator activity. Whether this increase results in the generation of plasmin in vivo has never been established.A novel sensitive radioimmunoassay (RIA) for the measurement of the complex between plasmin and its main inhibitor α2 antiplasmin (PAP complex) was developed using monoclonal antibodies preferentially reacting with complexed and inactivated α2-antiplasmin and monoclonal antibodies against plasmin. The assay was validated in healthy volunteers and in patients with an activated fibrinolytic system.Infusion of DDAVP in a randomized placebo controlled crossover study resulted in all volunteers in a 6.6-fold increase in PAP complex, which was maximal between 15 and 30 min after the start of the infusion. Hereafter, plasma levels of PAP complex decreased with an apparent half-life of disappearance of about 120 min. Infusion of DDAVP did not induce generation of thrombin, as measured by plasma levels of prothrombin fragment F1+2 and thrombin-antithrombin III (TAT) complex.We conclude that the increase in plasminogen activator activity upon the infusion of DDAVP results in the in vivo generation of plasmin, in the absence of coagulation activation. Studying the DDAVP induced increase in PAP complex of patients with thromboembolic disease and a defective plasminogen activator response upon DDAVP may provide more insight into the role of the fibrinolytic system in the pathogenesis of thrombosis.

On Metaphysics and the Political: A Polemics of Reading Baudelaire in the 1930s

2019 ◽  
Vol 58 (2) ◽  
pp. 249-259
Author(s):  
Joseph Acquisto
Keyword(s):  
Twentieth Century ◽  
Political Crisis ◽  
The Political ◽  
Modern Poetry ◽  
Progressive Politics ◽  
The World ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

This essay examines a polemic between two Baudelaire critics of the 1930s, Jean Cassou and Benjamin Fondane, which centered on the relationship of poetry to progressive politics and metaphysics. I argue that a return to Baudelaire's poetry can yield insight into what seems like an impasse in Cassou and Fondane. Baudelaire provides the possibility of realigning metaphysics and politics so that poetry has the potential to become the space in which we can begin to think the two of them together, as opposed to seeing them in unresolvable tension. Or rather, the tension that Baudelaire animates between the two allows us a new way of thinking about the role of esthetics in moments of political crisis. We can in some ways see Baudelaire as responding, avant la lettre, to two of his early twentieth-century readers who correctly perceived his work as the space that breathes a new urgency into the questions of how modern poetry relates to the world from which it springs and in which it intervenes.

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