scholarly journals Temporal variation in fish community in the tailrace at Três Marias Hydroelectric Dam, São Francisco River, Brazil

2012 ◽  
Vol 10 (4) ◽  
pp. 731-740 ◽  
Author(s):  
Raquel Coelho Loures ◽  
Paulo Santos Pompeu
Keyword(s):  
Temporal Variation ◽  
Fish Community ◽  
Migratory Species ◽  
Wet Season ◽  
Negative Effects ◽  
Hydroelectric Energy ◽  
Hydroelectric Dam ◽  
Dam Operation ◽  
The Impact ◽  
The Relationship

Damming rivers to generate hydroelectric energy causes a series of changes in the environment, including impacts on the ichthyofauna. Knowledge of the fish community immediately downstream from a hydroelectric dam can help to reduce the negative effects of dam operation, such as fish entrance into the draft tube during turbines maintenance. We evaluated the temporal variation in fish community composition and abundance, near Três Marias Hydroelectric Dam (TMD), and its relationship with abiotic variables. Samples (n = 18) were carried out using gill nets in the tailrace of the dam, over the course of a hydrological year, at six time points during a 24-hour period. Abiotic data were also sampled to assess the relationship with the biotic data. In the tailrace, Characiformes showed the highest richness, while Siluriformes were the most abundant. Of the 33 species sampled, six were migratory. The fish community was significantly different between the dry and wet seasons, with higher abundances during the wet season. In the wet season, the frequency of migratory species in the community rose from 0.7 to 18.3%, and Pimelodus maculatus accounted for 14.5% of the overall abundance. We observed that Characiformes captures occurred mainly in the morning, with peak activity between 5:00 and 9:00 h. Siluriformes showed greater nocturnal activity and were largely captured between 17:00 and 21:00 h. Synchronizing operational maneuvers that represent high risk to the fish with periods of low abundance in the tailrace, i.e., during months of low precipitation, may be a measure to reduce the impact of the operation on the downstream fish community.

scholarly journals Fish community structure of Juramento reservoir, São Francisco River basin, Minas Gerais, Brazil

2006 ◽  
Vol 23 (3) ◽  
pp. 832-840 ◽  
Author(s):  
André R. M. Silva ◽  
Gilmar B. Santos ◽  
Thiago Ratton
Keyword(s):  
Community Structure ◽  
Native Species ◽  
Fish Community ◽  
Fish Fauna ◽  
Fish Abundance ◽  
Fish Community Structure ◽  
Migratory Species ◽  
Wet Season ◽  
Dry Period ◽  
The Relationship

Many rivers in Brazil as the São Francisco (SFR) have been impounded for reservoirs construction purposes. However, there is a lack of knowledge on their fish fauna in many areas, including headwaters. The present study aimed to describe the fish community structure from Juramento reservoir, located on Juramento River, a branch of SFR basin. Six bimonthly samplings were made in four different sites. Gill and cast nets, beach seines and sieves were used to collect fish. Ecological indexes as well as the relationship between fish abundance and some limnological variables were determined. 3288 fish belonging to 33 species (16.5% of the total described for SFR basin) were captured, being 75.7% Characiformes, 18.1% Siluriformes, 3% Cyprinodontiformes and 3% Gymnotiformes. Only two non-native species, 'tamboatá' - Hoplosternum littorale (Hancock, 1828) and 'trairão' - Hoplias lacerdae Ribeiro, 1908 were found. The highest catches in number occurred in the dry period (March-October) and the lowest one in the wet season (November-February). Diversity was higher at Barragem station and richness did not vary between reservoir zones. Five migratory species were found downstream of the dam (four exclusively there), whereas only the 'curimbatá-pioa' - Prochilodus costatus Valenciennes, 1850 occurred in the reservoir. The low observed correlations between fish abundance and the limnological variables utilized suggest that the local fish fauna is not strongly affected by their variation.

Retrospective analysis of the resilience of Russian regions as socio-economic systems

2019 ◽  
pp. 46-64 ◽  
Author(s):  
Vladimir V. Klimanov ◽  
Sofiya М. Kazakova ◽  
Anna A. Mikhaylova
Keyword(s):  
Panel Data ◽  
Economic Systems ◽  
Financial Indicators ◽  
Russian Regions ◽  
Integral Index ◽  
Negative Effects ◽  
Economic Resilience ◽  
Correlation Dependence ◽  
The Impact ◽  
The Relationship

The article examines the impact of various socio-economic and financial indicators on the resilience of Russian regions. For each region, the integral index of resilience is calculated, and its correlation dependence with the selected indicators is revealed. The study confirms the relationship between fiscal resilience and socio-economic resilience of the regions. The analysis of panel data for 75 regions from 2007 to 2016 shows that there are significant differences in the dynamics of indicators in different periods. In particular, the degree of exposure to the negative effects of the crises of 2008—2009 and 2014—2015 in non-resilient regions is higher than in resilient ones.

scholarly journals Economic Security of the Region’s Periphery in Conditions of Digitalization, Urbanization and COVID-19

2021 ◽  
Vol 93 ◽  
pp. 05019
Author(s):  
E.B. Dvoryadkina ◽  
K.M. Guseynly ◽  
A.A. Sobyanin
Keyword(s):  
Economic Security ◽  
General Nature ◽  
Negative Effects ◽  
The Impact ◽  
The Relationship

The study deals with three factors of general nature and their impact on the economic security of the region's periphery. The essence of regional periphery economic security is described. Processes such as digitalization, urbanization and COVID-19 are considered and their impact on the economic security of the region's periphery is described. These factors are considered separately, and the characteristics of positive and negative effects coming from them are presented. The relationship between all three factors is revealed, and the influence of these processes in the aggregate is described. It was found that, cumulatively, the effect of digitalization, urbanization and COVID-19 on the economic security of the region's periphery is changing and may acquire a completely different nature than the impact of factors individually.

scholarly journals Effectiveness of Flexible Dam Operation and Sediment Replenishment at Managawa Dam, Japan

2018 ◽  
Vol 13 (4) ◽  
pp. 691-701 ◽  
Author(s):  
Katsumi Matsushima ◽  
Makoto Hyodo ◽  
Noriyuki Shibata ◽  
Yoshihiro Shimizu ◽  
◽  
...  
Keyword(s):  
Flood Pulse ◽  
Demonstration Project ◽  
Scale Analysis ◽  
Management Options ◽  
Ecological Processes ◽  
Fluvial Systems ◽  
Macro Scale ◽  
Dam Operation ◽  
The Impact ◽  
The Relationship

A field demonstration project on flexible dam operation at the Managawa dam in the Kuzuryu River Basin has been implemented since 2000. The goal is to restore flow and sediment regimes in the Managawa River, which flows along the Ono-city and is located below the dam. Flexible dam operation stores inflow discharge into a reservoir, which generally uses part of the flood control capacity and appropriately discharges the stored water to the river, also known as the “flood pulse,” for restoring dynamic fluvial systems and the resulting ecological processes. In addition, other options have been carried out in combination with flexible dam operation, for example, sediment replenishment since 2003 and channel rehabilitation since 2007. This article reveals the positive impacts and effectiveness of flexible dam operation, sediment replenishment, and channel rehabilitation, and discusses challenges and future prospects toward translating the field demonstration project into dam management on the ground level. First, we classified reach types to identify the impact of various management options, e.g., flexible dam operation, sediment replenishment, and channel rehabilitation. These management options can influence respected reaches. We conducted a macro-scale analysis to understand the relationship between the aforementioned management options and dynamic fluvial systems, addressing changes in gravel riverbed, vegetation, and habitat types (riffles and pools). Second, a micro-scale analysis was conducted to understand the relationship between the management option and changes in attached algae to sediment and macro-invertebrates, etc. The results show the effectiveness of the middle-scale flood pulse to restore dynamic fluvial systems, increase habitat diversity, and sustain ecological processes. Furthermore, we discussed the impacts of such options on the flow and sediment regimes in Managawa River and revealed that flexible dam operation reduces the occurrence of low flow and midscale floods. It was also revealed methods such as sediment replenishment and channel rehabilitation play an important role in increasing the effectiveness of the middle-scale flood pulse and restoring dynamic fluvial systems, even though sediment replenishment is not sufficient to restore sediment regimes (i.e., bring then back to pre-dam conditions).

scholarly journals Corruption and satisfaction with democracy: the conditional role of electoral disproportionality and ballot control

2018 ◽  
Vol 10 (3) ◽  
pp. 393-416 ◽  
Author(s):  
Alessandro Pellegata ◽  
Vincenzo Memoli
Keyword(s):  
Electoral Systems ◽  
Aggregate Level ◽  
Negative Effects ◽  
Empirical Results ◽  
Satisfaction With Democracy ◽  
Level Data ◽  
The Impact ◽  
The Relationship ◽  
Different Levels

Existing literature has analysed the relationship between electoral systems and either corruption or satisfaction with democracy (SWD) focussing on the traditional distinction between majoritarian and proportional systems. This paper, instead, investigates if and how specific aspects of electoral systems moderate the negative effects of corruption perceptions on SWD. We argue that two mechanisms act simultaneously but at different levels. The first mechanism is the relationship between voters and the national government, while the second links single representatives to their constituents. We advance conditional hypotheses that postulate an attenuating effect of disproportionality and a reinforcing impact of personal vote. Empirical results from 35 elections in 33 democracies, using both individual and aggregate-level data, confirm the research hypotheses. More disproportional electoral systems weaken the impact of citizens’ perceived corruption on their democratic satisfaction, while this is strengthened by systems in which the ballot control is mostly in the hand of the voters.

Intervening processes in the relationship between unemployment and health

1987 ◽  
Vol 17 (4) ◽  
pp. 949-961 ◽  
Author(s):  
Ronald C. Kessler ◽  
J. Blake Turner ◽  
James S. House
Keyword(s):  
Job Loss ◽  
The United States ◽  
Financial Strain ◽  
Physical And Mental Health ◽  
Negative Effects ◽  
Unemployed People ◽  
The Individual ◽  
Unemployment And Health ◽  
The Impact ◽  
The Relationship

SynopsisA considerable amount of research documents the negative effects of job loss on both physical and mental health. Yet we know comparatively little about the mechanisms through which these effects occur. Unemployment, like other events, is not the same experience for everyone exposed to it. An understanding of this variation might be facilitated by breaking down the analysis of unemployment into a consideration of the various stresses that it creates or exacerbates. This is our purpose in the present paper.We demonstrate that, for one area of the United States, the effect of job loss on several health outcomes involves two mechanisms: (1) unemployment results in increased financial strain which, in turn, results in negative health effects, and (2) unemployment leaves the individual more vulnerable to the impact of unrelated life events. Controlling for financial strain, unemployed people in our sample who have not experienced an additional life event in the previous year are in no worse health than the stably employed. This provides useful insights into the nature of the unemployment experience in this particular setting. It also provides a basis for future detailed explorations of the various ways people cope with this event.

scholarly journals A Vector Autoregression Analysis of Foreign Direct Investment and Its Link to Competitiveness

2020 ◽  
Vol 12 (4) ◽  
pp. 127-142
Author(s):  
Marinko Skare ◽  
Dajana Cvek
Keyword(s):  
Foreign Direct Investments ◽  
Negative Effects ◽  
Funding Sources ◽  
Stock Investment ◽  
Macroeconomic Indicators ◽  
Using Data ◽  
The Impact ◽  
The Relationship ◽  
Auto Regression ◽  
Macroeconomic Stability

This study has investigated the impact of foreign investments on competitiveness in Croatia in terms of macroeconomic stability conditions using data from 2002 to 2017. In this paper, we focus on the relationship between critical macroeconomic indicators and foreign direct investments (FDI) as a growth and competitiveness driving factor. To study the impact of FDI on competitiveness levels in Croatia, time series methods are used. Macroeconomic stability is a necessary but not sufficient condition for economic competitiveness. FDI can increase the level of economy’s competitiveness, although the total effect depends on the FDI structure (greenfield vs brownfield). The vector auto-regression (VAR) model and Granger causality have identified a decrease in FDI inflows in the recession period. There is a correlation between FDI, employment, GDP and exports. The goal of our study is to investigate the impact of FDI on macroeconomic indicators, FDI inflow determinants, and their impact on the overall competitiveness and growth. In this study, we identify and explain the positive and negative effects of FDI setting the framework for efficient macroeconomic policy. The results should serve policymakers in efforts to improve decisions that affect the country’s macroeconomic competitiveness. Significant differences were demonstrated in Croatia’s macroeconomic performance over the observed period. Our results show FDI as a potential inefficiency growth factor among selected indicators if it is not controlled in terms of investment structures and funding sources. The country’s competitiveness depends on stock investment, but even more on the structure of the FDI flowing in the economy.

scholarly journals Climate change impact to dam Operation, case study of Darma Dam, West Java

2022 ◽  
Vol 1212 (1) ◽  
pp. 012031
Author(s):  
A A Kuntoro ◽  
D T Ramadhani ◽  
A M S Idris ◽  
M Farid ◽  
M B Adityawan ◽  
...  
Keyword(s):  
Climate Change ◽  
Present Condition ◽  
Water Volume ◽  
Adaptation To Climate Change ◽  
Wet Season ◽  
West Java ◽  
Industrial Sectors ◽  
Dam Operation ◽  
Average Water ◽  
The Impact

Abstract Darma Dam is located in the upstream of Cisanggarung River, Kuningan Regency, West Java Province. Darma Dam construction dated from about 1922. Indonesian government continued the construction and began operating in 1962. With effective storage of about 40 million m3, Darma Dam provides water for about 22 thousand irrigation areas and bulk water for several cities and regencies. Several problems encountered in Darma Dam operation and water management are 1) increasing water demand from domestic and industrial sectors, and 2) high inflow variation during the dry and wet season, resulting in a large amount of water spill from the dam spillway. This paper addressed the impact of climate change on the inflow variation of Darma Dam in the dry and wet seasons. Further analysis shows average water spills from the spillway during the wet season may increase from about 12 million m3/year in the present condition to about 20 million m3/year in 2020-2050, while the average water volume during the dry season may reduce from 22.5 million m3 in the present condition to about 20.7 million m3 in 2020-2050. This study suggests that dam operation need adjustment in the future as part of adaptation to climate change.

Caring for a Loved One With Alzheimer’s Disease

2012 ◽  
Vol 27 (8) ◽  
pp. 579-583 ◽  
Author(s):  
Charles Van Liew ◽  
Terry A. Cronan
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Health Status ◽  
Cognitive Status ◽  
Negative Effects ◽  
Loved One ◽  
Social Burden ◽  
Independent Variable ◽  
The Impact ◽  
The Relationship

Objective: Alzheimer’s disease (AD) is associated with considerable caregiver and social burden. It is important to examine ways to minimize the negative effects of AD. Health care advocates (HCAs) may be one means of limiting the aversive effects of AD. Method: Participants completed a short survey that assessed their perceptions of the impact of comorbid AD on health status and their likelihood of hiring an HCA to assist in managing it. A mediational model was proposed: cognitive status (AD vs cognitively healthy) was the independent variable, perception of severity was the mediator, and the probability of hiring an HCA was the dependent variable. Results: The results indicated that the relationship between cognitive status and probability of hiring an HCA was fully mediated by perceptions of severity. Conclusion: This study demonstrated that participants appreciated the impact of AD on health status, and this translated into a greater probability of hiring an HCA.

scholarly journals Negative Impact of Social Network Services Based on Stressor-Stress-Outcome: The Role of Experience of Privacy Violations

2019 ◽  
Vol 11 (6) ◽  
pp. 137 ◽  
Author(s):  
Sanghyun Kim ◽  
Hyunsun Park ◽  
Moon Jong Choi
Keyword(s):  
Social Network ◽  
Structural Equation ◽  
Information Overload ◽  
Negative Impact ◽  
Equation Model ◽  
User Characteristics ◽  
Negative Effects ◽  
The Impact ◽  
The Relationship

Social network service (SNS) information has benefited many individuals. However, as such information has increased exponentially, the number of SNS users has increased dramatically and negative effects of SNSs on users have emerged. Many SNS users experience negative psychological conditions such as fatigue, burnout, and stress. Thus, in this study, we investigated the SNS and user characteristics that affect SNS fatigue, living disorder, and reduced SNS use intention. We developed a research model to examine the impact of two SNS characteristics (irrelevant information overload and open reachability) and two user characteristics (engagement and maintaining self-reputation) on SNS fatigue. We also examined the role of the experience of privacy violations in the relationship between living disorder and reduced SNS use intention. We collected data from 579 SNS users and created a partial least squares structural equation model to test the hypotheses. The results of the analysis showed that three factors, other than open reachability, positively affected SNS fatigue. Furthermore, we found that SNS fatigue significantly affected living disorder and reduced SNS use intention, and that experience of privacy violations significantly affected the relationship between living disorder and reduced SNS use intention. These results expand our understanding of SNS fatigue and users’ negative behaviors.

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