scholarly journals Semiarid ecosystem sensitivity to precipitation extremes: weak evidence for vegetation constraints

Ecology ◽  
2019 ◽  
Vol 100 (2) ◽  
pp. e02572 ◽  
Author(s):  
Andrew J. Felton ◽  
Sam Zavislan‐Pullaro ◽  
Melinda D. Smith
Keyword(s):  
Precipitation Extremes ◽  
Ecosystem Sensitivity ◽  
Weak Evidence ◽  
Semiarid Ecosystem

Misallocation of Investment in Europe

2018 ◽  
Author(s):  
Francesca Barbiero ◽  
Philipp-Bastian Brutscher ◽  
Atanas Kolev ◽  
Alexander Popov ◽  
Marcin Wolski
Keyword(s):  
Agency Problems ◽  
Growth Opportunities ◽  
Data Set ◽  
European Firm ◽  
Weak Evidence ◽  
Zombie Lending ◽  
Matched Data ◽  
Global Growth

Using a pan-European, firm-bank matched data set, we find weak evidence of investment misallocation in Europe. Firms with higher debt overhangs invest significantly less, in particular in sectors that are facing good global growth opportunities. We also find that firms with higher debt overhangs are more likely to invest if they borrow from undercapitalized banks, and this effect is particularly strong in industries facing good global growth opportunities, suggesting a misallocation of investment associated with ‘zombie lending’. Our results are consistent with theories of investment misallocation due to agency problems at firms and at banks.

scholarly journals Price adjustments on the Johannesburg Stock Exchange for unexpected and dramatic news events: An empirical analysis

1989 ◽  
Vol 20 (3) ◽  
pp. 119-128 ◽  
Author(s):  
N. Bhana
Keyword(s):  
Empirical Analysis ◽  
Stock Exchange ◽  
Abnormal Returns ◽  
Short Term ◽  
Johannesburg Stock Exchange ◽  
Price Adjustments ◽  
Weak Evidence ◽  
News Events ◽  
One Year

The objective of this study is to determine whether companies listed on the Johannesburg Stock Exchange overreacted to unexpected favourable and unfavourable company-specific news events during the period 1970 - 1984. The JSE appears to be inefficient in reacting to the announcement of unfavourable news; economically significant abnormal returns up to one year following the event are observed. The JSE does not appear to overreact to news of a favourable nature, there is only weak evidence of short-term overreaction. The selling pressure caused by panic selling could depress prices well below levels justified by the unfavourable news. The magnitude of the overreaction to unfavourable news is sufficient to enable astute investors to outperform the market by taking positions in these securities. Knowledge of the pattern of market overreaction can also be of value to investors for transactions that are to take place anyway.

scholarly journals Vegetation Change and Its Response to Climate Extremes in the Arid Region of Northwest China

2021 ◽  
Vol 13 (7) ◽  
pp. 1230
Author(s):  
Simeng Wang ◽  
Qihang Liu ◽  
Chang Huang
Keyword(s):  
Arid Region ◽  
Vegetation Change ◽  
Vegetation Index ◽  
Pearson Correlation ◽  
Time Lag ◽  
Climate Extremes ◽  
Northwest China ◽  
Precipitation Extremes ◽  
Temperature Extremes ◽  
Increasing Trend

Changes in climate extremes have a profound impact on vegetation growth. In this study, we employed the Moderate Resolution Imaging Spectroradiometer (MODIS) and a recently published climate extremes dataset (HadEX3) to study the temporal and spatial evolution of vegetation cover, and its responses to climate extremes in the arid region of northwest China (ARNC). Mann-Kendall test, Anomaly analysis, Pearson correlation analysis, Time lag cross-correlation method, and Least absolute shrinkage and selection operator logistic regression (Lasso) were conducted to quantitatively analyze the response characteristics between Normalized Difference Vegetation Index (NDVI) and climate extremes from 2000 to 2018. The results showed that: (1) The vegetation in the ARNC had a fluctuating upward trend, with vegetation significantly increasing in Xinjiang Tianshan, Altai Mountain, and Tarim Basin, and decreasing in the central inland desert. (2) Temperature extremes showed an increasing trend, with extremely high-temperature events increasing and extremely low-temperature events decreasing. Precipitation extremes events also exhibited a slightly increasing trend. (3) NDVI was overall positively correlated with the climate extremes indices (CEIs), although both positive and negative correlations spatially coexisted. (4) The responses of NDVI and climate extremes showed time lag effects and spatial differences in the growing period. (5) Precipitation extremes were closely related to NDVI than temperature extremes according to Lasso modeling results. This study provides a reference for understanding vegetation variations and their response to climate extremes in arid regions.

scholarly journals Towards Understanding Variability in Droughts in Response to Extreme Climate Conditions over the Different Agro-Ecological Zones of Pakistan

2021 ◽  
Vol 13 (12) ◽  
pp. 6910
Author(s):  
Adil Dilawar ◽  
Baozhang Chen ◽  
Arfan Arshad ◽  
Lifeng Guo ◽  
Muhammad Irfan Ehsan ◽  
...  
Keyword(s):  
Pearson Correlation ◽  
Principal Component ◽  
Mitigation Strategies ◽  
Precipitation Extremes ◽  
Climate Mitigation ◽  
Mean Annual Temperature ◽  
Climate Extreme ◽  
Ecological Zones ◽  
The Mean ◽  
Agro Ecological Zones

Here, we provided a comprehensive analysis of long-term drought and climate extreme patterns in the agro ecological zones (AEZs) of Pakistan during 1980–2019. Drought trends were investigated using the standardized precipitation evapotranspiration index (SPEI) at various timescales (SPEI-1, SPEI-3, SPEI-6, and SPEI-12). The results showed that droughts (seasonal and annual) were more persistent and severe in the southern, southwestern, southeastern, and central parts of the region. Drought exacerbated with slopes of −0.02, −0.07, −0.08, −0.01, and −0.02 per year. Drought prevailed in all AEZs in the spring season. The majority of AEZs in Pakistan’s southern, middle, and southwestern regions had experienced substantial warming. The mean annual temperature minimum (Tmin) increased faster than the mean annual temperature maximum (Tmax) in all zones. Precipitation decreased in the southern, northern, central, and southwestern parts of the region. Principal component analysis (PCA) revealed a robust increase in temperature extremes with a variance of 76% and a decrease in precipitation extremes with a variance of 91% in the region. Temperature and precipitation extremes indices had a strong Pearson correlation with drought events. Higher temperatures resulted in extreme drought (dry conditions), while higher precipitation levels resulted in wetting conditions (no drought) in different AEZs. In most AEZs, drought occurrences were more responsive to precipitation. The current findings are helpful for climate mitigation strategies and specific zonal efforts are needed to alleviate the environmental and societal impacts of drought.

Effect of the invasive exotic herb Centaurea solstitialis on plant communities of a semiarid ecosystem

2020 ◽  
Vol 13 (3-4) ◽  
pp. 267-275
Author(s):  
Pablo I. Becerra ◽  
Lohengrin Cavieres ◽  
Ramiro O. Bustamante
Keyword(s):  
Plant Communities ◽  
Centaurea Solstitialis ◽  
Semiarid Ecosystem ◽  
Invasive Exotic

The Age of Nonsynonymous and Synonymous Mutations in Animal mtDNA and Implications for the Mildly Deleterious Theory

Genetics ◽  
1999 ◽  
Vol 153 (1) ◽  
pp. 497-506 ◽  
Author(s):  
Rasmus Nielsen ◽  
Daniel M Weinreich
Keyword(s):  
Dna Sequences ◽  
Purifying Selection ◽  
Data Sets ◽  
Deleterious Mutations ◽  
Synonymous Mutations ◽  
Weak Evidence ◽  
Mitochondrial Data ◽  
The Mean ◽  
Excess Number ◽  
Neutral Mutations

Abstract McDonald/Kreitman tests performed on animal mtDNA consistently reveal significant deviations from strict neutrality in the direction of an excess number of polymorphic nonsynonymous sites, which is consistent with purifying selection acting on nonsynonymous sites. We show that under models of recurrent neutral and deleterious mutations, the mean age of segregating neutral mutations is greater than the mean age of segregating selected mutations, even in the absence of recombination. We develop a test of the hypothesis that the mean age of segregating synonymous mutations equals the mean age of segregating nonsynonymous mutations in a sample of DNA sequences. The power of this age-of-mutation test and the power of the McDonald/Kreitman test are explored by computer simulations. We apply the new test to 25 previously published mitochondrial data sets and find weak evidence for selection against nonsynonymous mutations.

scholarly journals Transfer effects in auditory temporal preparation occur using an unfilled but not filled foreperiod

2021 ◽  
pp. 174702182199545
Author(s):  
Emily M Crowe ◽  
Sander A Los ◽  
Louise Schindler ◽  
Christopher Kent
Keyword(s):  
Sensory Modality ◽  
Warning Signal ◽  
Convincing Evidence ◽  
Transfer Effects ◽  
Temporal Preparation ◽  
Memory Traces ◽  
Weak Evidence ◽  
Current Block ◽  
Visual Domain ◽  
Multiple Trace Theory

How quickly participants respond to a “go” after a “warning” signal is partly determined by the time between the two signals (the foreperiod) and the distribution of foreperiods. According to Multiple Trace Theory of Temporal Preparation (MTP), participants use memory traces of previous foreperiods to prepare for the upcoming go signal. If the processes underlying temporal preparation reflect general encoding and memory principles, transfer effects (the carryover effect of a previous block’s distribution of foreperiods to the current block) should be observed regardless of the sensory modality in which signals are presented. Despite convincing evidence for transfer effects in the visual domain, only weak evidence for transfer effects has been documented in the auditory domain. Three experiments were conducted to examine whether such differences in results are due to the modality of the stimulus or other procedural factors. In each experiment, two groups of participants were exposed to different foreperiod distributions in the acquisition phase and to the same foreperiod distribution in the transfer phase. Experiment 1 used a choice-reaction time (RT) task, and the warning signal remained on until the go signal, but there was no evidence for transfer effects. Experiments 2 and 3 used a simple- and choice-RT task, respectively, and there was silence between the warning and go signals. Both experiments revealed evidence for transfer effects, which suggests that transfer effects are most evident when there is no auditory stimulation between the warning and go signals.

scholarly journals German forecasters’ narratives: How informative are German business cycle forecast reports?

2021 ◽  
Author(s):  
Karsten Müller
Keyword(s):  
Business Cycle ◽  
Fixed Effects ◽  
Predictive Power ◽  
Recursive Estimation ◽  
Regression Methods ◽  
Inflation Forecasts ◽  
Fixed Effects Panel Regression ◽  
Weak Evidence ◽  
Out Of Sample ◽  
Different Characteristics

AbstractBased on German business cycle forecast reports covering 10 German institutions for the period 1993–2017, the paper analyses the information content of German forecasters’ narratives for German business cycle forecasts. The paper applies textual analysis to convert qualitative text data into quantitative sentiment indices. First, a sentiment analysis utilizes dictionary methods and text regression methods, using recursive estimation. Next, the paper analyses the different characteristics of sentiments. In a third step, sentiment indices are used to test the efficiency of numerical forecasts. Using 12-month-ahead fixed horizon forecasts, fixed-effects panel regression results suggest some informational content of sentiment indices for growth and inflation forecasts. Finally, a forecasting exercise analyses the predictive power of sentiment indices for GDP growth and inflation. The results suggest weak evidence, at best, for in-sample and out-of-sample predictive power of the sentiment indices.

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