scholarly journals Do successive climate extremes weaken the resistance of plant communities? An experimental study using plant assemblages

2014 ◽  
Vol 11 (1) ◽  
pp. 109-121 ◽  
Author(s):  
F. E. Dreesen ◽  
H. J. De Boeck ◽  
I. A. Janssens ◽  
I. Nijs
Keyword(s):  
Plant Communities ◽  
Extreme Event ◽  
Recovery Period ◽  
Climate Extremes ◽  
Herbaceous Plant ◽  
Short Term ◽  
Positive Effects ◽  
Negative Effect ◽  
Plant Assemblages ◽  
Heat Extremes

Abstract. The probability that plant communities undergo successive climate extremes increases under climate change. Exposure to an extreme event might elicit acclimatory responses and thereby greater resistance to a subsequent event, but might also reduce resistance if the recovery period is too short or resilience too low. Using experimental herbaceous plant assemblages, we compared the effects of two successive extremes occurring in one growing season (either two drought extremes, two heat extremes or two drought + heat extremes) to those of assemblages being exposed only to the second extreme. Additionally, the recovery period between the successive extremes was varied (2, 3.5 or 6 weeks). Among the different types of climate extremes, combined heat + drought extremes induced substantial leaf mortality and plant senescence, while the effects of drought and heat extremes were smaller. Preceding drought + heat extremes lowered the resistance in terms of leaf survival to a subsequent drought + heat extreme if the recovery period was two weeks, even though the leaves had completely recovered during that interval. No reduced resistance to subsequent extremes was recorded with longer recovery times or with drought or heat extremes. Despite the substantial mortality on the short term, the drought + heat and the heat extremes increased the end-of-season aboveground biomass independent of the number of extreme events or the duration of the recovery period. These results show that recurrent climate extremes with short time intervals can weaken the resistance of herbaceous plant assemblages. This negative effect in the short term can, however, be compensated in the longer term through rapid recovery and secondary positive effects.

scholarly journals Do successive climate extremes weaken the resistance of plant communities? An experimental study using plant assemblages

2013 ◽  
Vol 10 (6) ◽  
pp. 9149-9177 ◽  
Author(s):  
F. E. Dreesen ◽  
H. J. De Boeck ◽  
I. A. Janssens ◽  
I. Nijs
Keyword(s):  
Plant Communities ◽  
Extreme Event ◽  
Recovery Period ◽  
Climate Extremes ◽  
Experimental Plant ◽  
Herbaceous Plant ◽  
Positive Effects ◽  
Plant Assemblages ◽  
Effects Of Drought ◽  
Heat Extremes

Abstract. The probability that plant communities undergo successive climate extremes increases under climate change. Exposure to an extreme event might elicit acclimatory responses and thereby greater resistance to a subsequent event, but might also reduce resistance if the recovery period is too short or resilience too low. Using experimental plant assemblages, we compared the effects of two successive extremes (either two drought extremes, two heat extremes or two drought + heat extremes) to those of assemblages being exposed only to the second extreme. Additionally, the recovery period between the successive extremes was varied (2, 3.5 or 6 weeks). Among the different types of climate extremes, combined drought + heat extremes induced substantial leaf and plant mortality, while the effects of drought and heat extremes were smaller. Preceding drought + heat extremes lowered the resistance in terms of leaf survival to a subsequent drought + heat extreme if the recovery period was 2 weeks, even though the leaves had completely recovered during that interval. No reduced resistance to subsequent extremes was recorded with longer recovery times or with drought or heat extremes. Despite mortality on the short term, the drought + heat and the heat extremes increased the end-of-season aboveground biomass, independent of the number of events or the recovery period. These results show that the effect of a preceding extreme event disappears quite quickly, but that recurrent climate extremes with short time intervals can weaken the resistance of herbaceous plant assemblages. This can however be compensated afterwards through rapid recovery and secondary, positive effects in the longer term.

scholarly journals Recovery dynamics and invasibility of herbaceous plant communities after exposure to fifty-year climate extremes in different seasons

2013 ◽  
Vol 10 (10) ◽  
pp. 15851-15877
Author(s):  
F. E. Dreesen ◽  
H. J. De Boeck ◽  
I. A. Janssens ◽  
I. Nijs
Keyword(s):  
Plant Communities ◽  
Extreme Event ◽  
Climate Extremes ◽  
Community Response ◽  
Herbaceous Plant ◽  
Heat Extremes ◽  
One Year ◽  
Recovery Dynamics ◽  
Species Specific ◽  
Heat Events

Abstract. Disturbance events such as climatic extremes may enhance the invasibility of plant communities, through the creation of gaps and the associated local increase in available resources. In this study, experimental herbaceous communities consisting of three species were subjected to 50 yr extreme drought and/or heat events, in spring, summer or autumn. In the year of the induced extremes, species mortality and end-of-season biomass were examined. In two subsequent years without further disturbances, establishment of new species was recorded. The drought and drought + heat extremes in summer and autumn induced greater plant mortality compared with the heat extremes in those seasons and compared with all extremes applied in spring, in all three originally planted species. Recovery in terms of biomass towards the end of the growing season, however, was species-specific. The dominant species, the nitrogen fixer Trifolium repens, recovered poorly from the drought and drought + heat extremes which governed the community response. Community biomass, which was heavily affected by the drought and especially by the drought + heat events in summer and autumn, reached control values already one year later. Invasibility was increased in the communities that underwent the drought + heat extremes in the first year following the extreme events, but no longer in the second year. During the two years of invasion, the community composition changed, but independently of the type and impact of the extreme event. In short, the extreme climate events greatly affected the survival and productivity of the species, modified the species composition and dominance patterns, and increased the invasibility of our plant communities. However, none of these community properties seemed to be affected in the long term, as the induced responses faded out after one or two years.

Health Economics of the Workplace: Workplace Accidents and Effects of Job Loss and Retirement

2019 ◽  
Author(s):  
Jan C. van Ours
Keyword(s):  
Mental Health ◽  
Cognitive Skills ◽  
Job Loss ◽  
Working Hours ◽  
Workplace Safety ◽  
Physical And Mental Health ◽  
Short Term ◽  
Positive Effects ◽  
Workplace Accidents ◽  
Negative Effect

There are three main topics in research on the effects of work on health. The first topic is workplace accidents where the main issues are reporting behavior and workplace safety policies. A worker seems to be less inclined to report a workplace accident for fear of job loss when unemployment is high or when the worker has a temporary contract that may not be renewed. Workplace safety legislation has intended to reduce the incidence and severity of workplace accidents but empirical evidence on this result is unclear. The second topic is employment and health where the focus is on how job characteristics and job loss affect health, in particular mental health. Physically demanding jobs have negative health effects. The effects of working hours vary and the effects of job loss on physical and mental health are not uniform. Job loss seems to increase mortality. The third topic concerns retirement and health. Retirement seems to have a negative effect on cognitive skills and short-term positive effects on overall health. Other than that, the effects are very inconsistent, that is, even with as clear a measure as mortality, it is not clear whether life expectancy goes up, goes down, or remains constant due to retirement.

The time since castration influences the effects of short-term starvation on gonadotrophin secretion in male rats

1994 ◽  
Vol 143 (2) ◽  
pp. 209-219 ◽  
Author(s):  
M Bergendahl ◽  
I Huhtaniemi
Keyword(s):  
Fold Increase ◽  
Male Rats ◽  
Mrna Levels ◽  
Short Term ◽  
Positive Effects ◽  
Gnrh Receptors ◽  
Gonadotrophin Secretion ◽  
Gnrh Release ◽  
Negative Effect ◽  
Starvation Effect

Abstract Short-term starvation suppresses the pituitary-testicular function in rats, evidently through inhibition of gonadotrophin-releasing hormone (GnRH) release. However, when gonadotrophin secretion is strongly enhanced, e.g. after castration, starvation does not suppress gonadotrophins. To test whether the time since castration affects the pituitary response to starvation, adult male rats were totally deprived of food for five days (only water allowed) immediately (acute castration) or two weeks after castration (chronic castration). The pituitary contents of GnRH receptors were decreased by starvation in sham-operated animals, unaffected in acutely castrated rats, but increased in chronically castrated animals, in comparison with appropriate controls (P<0·01). Castration per se increased steady-state mRNA levels of the common α-chain and the LH and FSH β-chains in all groups studied. The only consistent effect of starvation on these parameters was the 1·7 to 2-fold increase in the pituitary content of LH β-subunit mRNA in acutely and chronically castrated rats (P<0·01). Starvation alone suppressed LH secretion, acute castration eliminated this effect, but in chronically castrated rats, the starvation effect was stimulatory. Starvation did not affect FSH secretion in sham-operated and acutely castrated rats, but after chronic castration, the effect was stimulatory. In conclusion, the overall effect of starvation on gonadotrophins shifts gradually after castration from suppression, in sham-operated rats, to stimulation, in chronically castrated animals. Parallel changes in pituitary GnRH receptors suggest similar changes in GnRH secretion. Hence, starvation has both negative and positive effects on the GnRH-gonadotrophin-axis. The negative effect is evidently androgen-dependent and dominates in testes-intact animals. After chronic castration, only the positive, non-androgen dependent, stimulatory effect remains. Journal of Endocrinology (1994) 143, 209–219

scholarly journals Recovery dynamics and invasibility of herbaceous plant communities after exposure to experimental climate extremes

2015 ◽  
Vol 16 (7) ◽  
pp. 583-591 ◽  
Author(s):  
Freja E. Dreesen ◽  
Hans J. De Boeck ◽  
Joanna A. Horemans ◽  
Ivan A. Janssens ◽  
Ivan Nijs
Keyword(s):  
Plant Communities ◽  
Climate Extremes ◽  
Herbaceous Plant ◽  
Recovery Dynamics

scholarly journals Short-term plant-community responses to large mammalian herbivore exclusion in a rewilded Javan savanna

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255056
Author(s):  
Arjun B. Potter ◽  
Muhammad Ali Imron ◽  
Satyawan Pudyatmoko ◽  
Matthew C. Hutchinson
Keyword(s):  
Plant Species ◽  
Plant Community ◽  
Plant Communities ◽  
Growing Season ◽  
Developmental Trajectory ◽  
Imperata Cylindrica ◽  
Herbaceous Plant ◽  
Short Term ◽  
Mammalian Herbivores ◽  
Herbivore Exclusion

Grassy biomes such as savannas are maintained by an interacting suite of ecosystem processes from herbivory to rainfall to fire. Many studies have examined the impacts of large mammalian herbivores on herbaceous plant communities, but few of these studies have been conducted in humid, fertile savannas. We present the findings of a short-term experiment that investigated the effects of herbivory in a fertile, humid, and semi-managed savanna. We erected large-herbivore exclosures in Alas Purwo National Park, Java, Indonesia where rainfall is high and fire is suppressed to test how herbivores impact plant community development across the growing season. Where large mammalian herbivores were excluded, herbaceous plant communities contained more non-grasses and were less similar; diverging in their composition as the growing season progressed. Effects of herbivore exclusion on plant species richness, evenness, and biomass per quadrat were generally weak. Notably, however, two weedy plant species (one native, Imperata cylindrica and one introduced, Senna cf. tora) appeared to benefit most from herbivore release. Our results suggest that heavy grazing pressure by native large mammalian herbivores controlled the composition of the herbaceous plant community. Moreover, exclusion of large mammalian herbivores led to divergence in the plant species composition of exclosures; compositional dissimilarity between herbivore-exclusion plots was higher than between plots exposed to large mammalian herbivores. Our findings suggest that, at this high-rainfall site, large mammalian herbivores constrained the developmental trajectory of plant communities across the growing season.

Methods for Calculation of Annual and Extreme Overflow Events from Combined Sewer Systems

1984 ◽  
Vol 16 (8-9) ◽  
pp. 311-325 ◽  
Author(s):  
N B Johansen ◽  
P Harremoës ◽  
M Jensen
Keyword(s):  
Extreme Event ◽  
Short Term ◽  
Sewer Systems ◽  
Extreme Load ◽  
Combined Sewer ◽  
Receiving Waters ◽  
Water Problems ◽  
Source Of Pollution ◽  
Receiving Water

Overflow from combined systems constitute an increasing source of pollution of receiving waters, as compared to daily wastewater discharges which undergo treatment to a still higher extent. The receiving water problems from overflows are significant both in a long term scale (mean annual load) and in a short term scale (extreme event load). A method for computation of both annual and extreme load is presented. It is based on historical rain series and the use of a time-area model and simple pollutant mixing model in runoff calculation. Statistical calculations for both mean annual load and extreme events have been applied to the computed overflow series. Based on the computerized method simple manual calculations methods have been developed, resulting in graphs and tables for annual load and extreme load.

scholarly journals FRI0632-HPR PSYCHOLOGICAL PARTICULIARITIES OF PATIENTS SUFFERING FROM MONOGENIC AUTO-INFLAMMATORY DISEASES.

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 920.1-921
Author(s):  
N. Stepanenko ◽  
E. Fedorov ◽  
S. Salugina ◽  
S. Feoktistova
Keyword(s):  
Inflammatory Diseases ◽  
Life Quality ◽  
Information Storage ◽  
Social Adaptation ◽  
Long Term Memory ◽  
Short Term ◽  
Sequence Of Events ◽  
Communicative Disorders ◽  
Negative Effect ◽  
High Level

Background:Monogenic auto-inflammatory diseases (mAID) are a group of severe chronic multisystemic diseases with recurring episodes of fever and other manifestations that significantly affect the patients’ life quality. Moreover, the hyper expression of pro-inflammatory cytokines (IL1β, etc.) observed in these patients may have a negative effect on the central nervous system.Objectives:to study the state of the cognitive and emotional spheres in children suffering from monogenic auto-inflammatory diseases.Methods:there were examined 22 children at the age of 7 to 17 years old diagnosed with CAPS-9, TRAPS-8, FMF-5. Among them there were 12 boys and 10 girls. The diagnosis in all the patients was confirmed through detection of pathogenic mutations in the NLRP3, TNFRSF1A and MEFV genes. The following methods were used: a clinical conversation; memory diagnostics (learning by heart of 10 words, a pictogram using cues taking into account the patients’ age); attention diagnostics (Schulte tables); thinking diagnostics (establishing a sequence of events, “four is a crwod”, simple analogies, interpretation of proverbs); emotional and communicative fields (the Eight-Color Luscher Test; CMAS (adaptation by A. Prikhozhan); STAI test, a drawing called “an animal that does not exist” and “a house-a tree-a man”).Results:The memory study revealed in all patients with TRAPS and FMF high and medium values of short-term and long-term memory, in patients with CAPS - a low level of short-term auditory-speech memory, information storage and indirect memorization in 1/3 of patients. In 100% of the examined patients with TRAPS, a significant decrease in all processes of attention and distribution of attention. In 1/3 of patients with CAPS, an increased exhaustion of attention was registered and in 11% - a decrease in its stability. In patients with FMF, attention disorders were not detected. In 44% of patients with CAPS, a decrease in the level of generalization and difficulties in establishing causal relationships were registered. In 25% of patients with TRAPS a decrease in the level of generalization, in 12.5%- difficulties in establishing cause-effect relationships, inertia of thinking in 37.5%. In 60% of patients with FMF: a decrease in the level of generalization, in 80%: difficulties in establishing cause-effect relationships, inertia of thinking in 20%. In the emotional sphere, patients with CAPS, TRAPS, and FMF demonstrated signs of aggression (11.1%, 20% and 20% of patients, respectively), communicative disorders (77.8% -80% - 80%), and reduced social adaptation (55.5% - 80% - 80%), a tendency to form neurotic fears (22% - 40% - 40%). A high level of personal anxiety was noted in 1/3 of patients with CAPS and 40% of patients with FMF.Conclusion:various psychological disorders in the cognitive and emotional fields were noted in the majority of the examined patients with monogenic auto-inflammatory diseases. In patients with TRAPS, attention processes are most significantly affected; in patients with CAPS, memory is more often affected. In patients with FMF, disorders in thinking processes are revealed more often. In the emotional sphere, most patients with all the three forms of AID note communicative disorders and social adaptation.Disclosure of Interests:None declared

Effects of Short-Term Mission Trips on Recipients’ Self-Esteem and Readiness for Self-Directed Learning

2021 ◽  
pp. 009164712110115
Author(s):  
Charissa H. W. Wong ◽  
Li Neng Lee ◽  
Alberto Pérez Pereiro
Keyword(s):  
Self Esteem ◽  
Control Group ◽  
Short Term ◽  
Self Directed Learning ◽  
Positive Effects ◽  
Post Test ◽  
Quasi Experimental ◽  
Directed Learning ◽  
Group Post ◽  
Mission Trips

Short-term Christian overseas volunteer trips, also known as short-term mission trips (STMs), have become increasingly prevalent (Howell & Dorr, 2007). However, research on these programs has been limited. This quasi-experimental study adds to the literature by quantitatively measuring the effects of an STM from Singapore to Thailand. STM recipients’ ( n = 44) self-esteem and readiness for self-directed learning (RSDL) were compared across timepoints – pre-test, post-test, follow-up – and with a control group ( n = 50). It was hypothesized that recipients would experience an increase in self-esteem and RSDL such that their scores would be higher than the control group post-STM. Results provide partial support for the hypotheses; while improvements among recipients were either not significant (for self-esteem) or not long-lasting (for RSDL), recipients had higher scores than the control group post-STM. This suggests that STMs have some, albeit limited, positive effects. Recommendations for promoting greater and longer-lasting effects are offered.

scholarly journals Paleolithic Diet—Effect on the Health Status and Performance of Athletes?

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 1019
Author(s):  
Barbara Frączek ◽  
Aleksandra Pięta ◽  
Adrian Burda ◽  
Paulina Mazur-Kurach ◽  
Florentyna Tyrała
Keyword(s):  
Blood Pressure ◽  
Body Mass ◽  
Positive Impact ◽  
Model Assessment ◽  
Paleolithic Diet ◽  
Short Term ◽  
Positive Effects ◽  
Short And Long Term ◽  
The Impact

The aim of this meta-analysis was to review the impact of a Paleolithic diet (PD) on selected health indicators (body composition, lipid profile, blood pressure, and carbohydrate metabolism) in the short and long term of nutrition intervention in healthy and unhealthy adults. A systematic review of randomized controlled trials of 21 full-text original human studies was conducted. Both the PD and a variety of healthy diets (control diets (CDs)) caused reduction in anthropometric parameters, both in the short and long term. For many indicators, such as weight (body mass (BM)), body mass index (BMI), and waist circumference (WC), impact was stronger and especially found in the short term. All diets caused a decrease in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), albeit the impact of PD was stronger. Among long-term studies, only PD cased a decline in TC and LDL-C. Impact on blood pressure was observed mainly in the short term. PD caused a decrease in fasting plasma (fP) glucose, fP insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) and glycated hemoglobin (HbA1c) in the short run, contrary to CD. In the long term, only PD caused a decrease in fP glucose and fP insulin. Lower positive impact of PD on performance was observed in the group without exercise. Positive effects of the PD on health and the lack of experiments among professional athletes require longer-term interventions to determine the effect of the Paleo diet on athletic performance.

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