scholarly journals Physical controls and a priori estimation of raising land surface elevation across the southwestern Bangladesh delta using Tidal River Management

2021 ◽  
Author(s):  
Md Feroz Islam ◽  
Paul P. Schot ◽  
Stefan C. Dekker ◽  
Jasper Griffioen ◽  
Hans Middelkoop

Abstract. The Ganges-Brahmaputra-Meghna delta in Bangladesh is one of the largest and most populated deltas in the world and threatened by relative sea level rise (RSLR). Renewed sediment deposition through tidal river management (TRM), a controlled flooding with dike breach, inside the lowest parts of the delta polders (so-called “beels”) can potentially counterbalance RSLR. The potential of TRM application in different beels across southwestern Bangladesh, however, still remains to be determined. We used a 2D morphodynamic model to explore the physical controls of five variables on total sediment deposition inside the beels during TRM: river tidal range (TR), river suspended sediment concentration (SSC), inundation depth (ID), width of the inlet (IW) and surface area of the beel (BA). Non-linear regression models (NLMs) were developed using the results of 2D models to quantify how sediment deposition inside the beels depends on these variables. The NLMs have an average coefficient of determination of 0.74 to 0.77. Application of the NLMs to 234 beels of southwestern Bangladesh indicates that TRM operation in beels located closer to the sea will retain more sediment as a result of decreasing SSC further inland. Beels in the western part retain more sediment because of lower average land surface elevation. Smaller beels have higher potential to raise land surface elevation due to nonlinear increase of sediment deposition per day (SPD) with beel area. Compartmentalization of larger beels may increase their potential to raise land surface elevation. Thus, the length of time of TRM application in cyclic order will need to vary across the delta to counterbalance RSLR, depending on current beel land surface elevation and local TRM sediment accumulation rates. We found that operating TRM only during the monsoon season is sufficient to raise land surface in 96 % and 80 % of all beels by more than 3 and 5 times the yearly RSLR, respectively. Applying TRM only seasonally offers huge advantages as to keeping the land available for agriculture during the rest of the year. The methodology presented here applying regression models based on 2D morphodynamic modeling may be used for the low-lying sinking deltas around the world to provide an a-priori estimation of sediment deposition from controlled flooding to counterbalance RSLR.

Author(s):  
Roberto D. Hernández

This article addresses the meaning and significance of the “world revolution of 1968,” as well as the historiography of 1968. I critically interrogate how the production of a narrative about 1968 and the creation of ethnic studies, despite its world-historic significance, has tended to perpetuate a limiting, essentialized and static notion of “the student” as the primary actor and an inherent agent of change. Although students did play an enormous role in the events leading up to, through, and after 1968 in various parts of the world—and I in no way wish to diminish this fact—this article nonetheless argues that the now hegemonic narrative of a student-led revolt has also had a number of negative consequences, two of which will be the focus here. One problem is that the generation-driven models that situate 1968 as a revolt of the young students versus a presumably older generation, embodied by both their parents and the dominant institutions of the time, are in effect a sociosymbolic reproduction of modernity/coloniality’s logic or driving impulse and obsession with newness. Hence an a priori valuation is assigned to the new, embodied in this case by the student, at the expense of the presumably outmoded old. Secondly, this apparent essentializing of “the student” has entrapped ethnic studies scholars, and many of the period’s activists (some of whom had been students themselves), into said logic, thereby risking the foreclosure of a politics beyond (re)enchantment or even obsession with newness yet again.


Author(s):  
Donald C. Williams

This chapter begins with a systematic presentation of the doctrine of actualism. According to actualism, all that exists is actual, determinate, and of one way of being. There are no possible objects, nor is there any indeterminacy in the world. In addition, there are no ways of being. It is proposed that actual entities stand in three fundamental relations: mereological, spatiotemporal, and resemblance relations. These relations govern the fundamental entities. Each fundamental entity stands in parthood relations, spatiotemporal relations, and resemblance relations to other entities. The resulting picture is one that represents the world as a four-dimensional manifold of actual ‘qualitied contents’—upon which all else supervenes. It is then explained how actualism accounts for classes, quantity, number, causation, laws, a priori knowledge, necessity, and induction.


Author(s):  
Barry Stroud

This chapter presents a straightforward structural description of Immanuel Kant’s conception of what the transcendental deduction is supposed to do, and how it is supposed to do it. The ‘deduction’ Kant thinks is needed for understanding the human mind would establish and explain our ‘right’ or ‘entitlement’ to something we seem to possess and employ in ‘the highly complicated web of human knowledge’. This is: experience, concepts, and principles. The chapter explains the point and strategy of the ‘deduction’ as Kant understands it, as well as the demanding conditions of its success, without entering into complexities of interpretation or critical assessment of the degree of success actually achieved. It also analyses Kant’s arguments regarding a priori concepts as well as a posteriori knowledge of the world around us, along with his claim that our position in the world must be understood as ‘empirical realism’.


1999 ◽  
Vol 20 (1-2) ◽  
pp. 18-34 ◽  
Author(s):  
Stephen Houlgate

It is a commonplace among certain recent philosophers that there is no such thing as the essence of anything. Nietzsche, for example, asserts that things have no essence of their own, because they are nothing but ceaselessly changing ways of acting on, and reacting to, other things. Wittgenstein, famously, rejects the idea that there is an essence to language and thought — at least if we mean by that some a priori logical structure underlying our everyday utterances. Finally, Richard Rorty urges that we “abandon […] the notion of ‘essence’ altogether”, along with “the notion that man's essence is to be a knower of essences”.It would be wrong to maintain that these writers understand the concept of essence in precisely the same way, or that they are all working towards the same philosophical goal. Nevertheless, they do share one aim in common: to undermine the idea that there is some deeper reality or identity underlying and grounding what we encounter in the world, what we say and what we do. That is to say, they may all be described as anti-foundationalist thinkers — thinkers who want us to attend to the specific processes and practices of nature and humanity without understanding them to be the product of some fundamental essence or “absolute”.


2010 ◽  
Vol 33 (2-3) ◽  
pp. 61-83 ◽  
Author(s):  
Joseph Henrich ◽  
Steven J. Heine ◽  
Ara Norenzayan

AbstractBehavioral scientists routinely publish broad claims about human psychology and behavior in the world's top journals based on samples drawn entirely from Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. Researchers – often implicitly – assume that either there is little variation across human populations, or that these “standard subjects” are as representative of the species as any other population. Are these assumptions justified? Here, our review of the comparative database from across the behavioral sciences suggests both that there is substantial variability in experimental results across populations and that WEIRD subjects are particularly unusual compared with the rest of the species – frequent outliers. The domains reviewed include visual perception, fairness, cooperation, spatial reasoning, categorization and inferential induction, moral reasoning, reasoning styles, self-concepts and related motivations, and the heritability of IQ. The findings suggest that members of WEIRD societies, including young children, are among the least representative populations one could find for generalizing about humans. Many of these findings involve domains that are associated with fundamental aspects of psychology, motivation, and behavior – hence, there are no obviousa priorigrounds for claiming that a particular behavioral phenomenon is universal based on sampling from a single subpopulation. Overall, these empirical patterns suggests that we need to be less cavalier in addressing questions ofhumannature on the basis of data drawn from this particularly thin, and rather unusual, slice of humanity. We close by proposing ways to structurally re-organize the behavioral sciences to best tackle these challenges.


Author(s):  
Alexander Dmitrievich Baev ◽  
◽  
Dmitry Alexandrovich Chechin ◽  
Sergey Alexandrovich Shabrov ◽  
Natalya Ivanovna Rabotinskaya ◽  
...  

2015 ◽  
Vol 7 (2) ◽  
pp. 262-279 ◽  
Author(s):  
Zhichao Guo ◽  
Yuanhua Feng ◽  
Thomas Gries

Purpose – The purpose of this paper is to investigate changes of China’s agri-food exports to Germany caused by China’s accession to WTO and the global financial crisis in a quantitative way. The paper aims to detect structural breaks and compare differences before and after the change points. Design/methodology/approach – The structural breaks detection procedures in this paper can be applied to find out two different types of change points, i.e. in the middle and at the end of one time series. Then time series and regression models are used to compare differences of trade relationship before and after the detected change points. The methods can be employed in any economic series and work well in practice. Findings – The results indicate that structural breaks in 2002 and 2009 are caused by China’s accession to WTO and the financial crisis. Time series and regression models show that the development of China’s exports to Germany in agri-food products has different features in different sub-periods. Before 1999, there is no significant relationship between China’s exports to Germany and Germany’s imports from the world. Between 2002 and 2008 the former depends on the latter very strongly, and China’s exports to Germany developed quickly and stably. It decreased, however suddenly in 2009, caused by the great reduction of Germany’s imports from the world in that year. But China’s market share in Germany still had a small gain. Analysis of two categories in agri-food trade also leads to similar conclusions. Comparing the two events we see rather different patterns even if they both indicate structural breaks in the development of China’s agri-food exports to Germany. Originality/value – This paper partly originally proposes two statistical algorithms for detecting different kinds of structural breaks in the middle part and at the end of a short-time series, respectively.


2018 ◽  
Vol 20 (91) ◽  
pp. 28-32
Author(s):  
B. B. Brychka

The study is concentrated on examination the impact of FDI on economic growth in the World during 1975–2015. The study consists of four consecutive parts, including introduction, literature review, model and methodology, data, empirical results and conclusion. Each part of the study is focused on its own goals. According to the results of the literature review, there is positive influence of FDI on economic growth in various countries. Economic growth is one of the most important goals of any country. The country image on the international level is dependent on its economic power. Economic growth provides an opportunity to improve the living standards in the country. Most researchers conclude that there is a positive influence of FDI on the countries’ economic growth. However, the impact of FDI is strong in developing countries. Moreover, this relationship is stronger in countries with higher educational and technological level, trade openness and development of the countries’ stock markets. Economists often build regression models to estimate the relationship between the variables. In order to find the impact of FDI on economic growth, we are going to apply linear regression models. We take two variables as indicators of the countries’ economic growth, including current GDP expressed in U.S dollars, and annual GDP growth rate. Taking into account that the World’s GDP in current U.S dollar is a factor variable with the mentioned resulting variables, the regression equation looks as follows: The R-squared of the built model is 0.99, indicating that roughly 100% of changes in the World’s GDP is caused by the chosen factors. As it is seen from the SAS output, the residuals of dependent variable and factors variables are distributed normally among its average value. Thus, non-normality is not observed in the model. Taking into account the coefficients of the factor variables, the log GDP is most sensitive to the changes in trade as a percent of GDP. The log GDP is not quite sensitive to the changes in FDI, since the coefficient of 0.000128 means that increasing of FDI by one unit increase the logarithmic value of GDP by $ 0.000128.


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