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Chapter 4 examines the role of the Constitutional Court of the Czech Republic, which in the first decade of its operation (from 1993 to the beginning of the new millennium) dealt mainly with the protection of fundamental rights, as well as with cases concerning transitional justice. With reference to this matter, the Court was called on to rule on particularly divisive issues concerning the country’s past, such as the law on the illegitimacy of the Communist regime, the laws on the restitution of property, as well as the “lustration laws,” which were aimed at preventing individuals involved with the Communist regime, or considered to be in favor of a return to Communism, from occupying higher positions in the state apparatus for a certain period. Compared to the previous generations, a distinguishing feature of this third generation of courts is the interplay between the democratic transition, constitutional justice, and accession to the Council of Europe and the European Union.
Chapter 5 brings things together with an analysis of the key lessons drawn from the discussion in the preceding chapters. In particular, it makes a comparison among the three generations of constitutional courts by topic, rather than country by country. This last chapter carries out an analysis of the various types of intervention of the constitutional judges, the reasons for the success of the centralized system of constitutional review, as well as the various factors influencing the activity of the courts. The analysis of the three generations shows that thanks to the actions carried out during the transition processes, the constitutional courts have managed to achieve full legitimation in their respective constitutional systems and within the dynamics of their respective forms of government. Although their action was not immune to criticism, the constitutional courts emerged as key players of the substantive transitions, reducing the high degree of uncertainty that characterizes the outcome of every transition process, and heading off the risk of ending up in a situation of constitutions without constitutionalism.
Chapter 2 analyzes the role played by the Italian Constitutional Court. This court belongs to the first generation of constitutional courts, and as a result its configuration and role at the time when it was established were largely experimental, if not a leap in the dark. The constitutional judges, especially during the initial phase (from 1956 until the end of the 1960s) focused on the elimination of the Fascist legislation that continued to severely constrain civil, political, religious, and social liberties. In this way the court made a break with the past, as it contributed to putting an end to the continuity between Fascism and post-Fascism, at least from a legislative point of view. Indeed, with the striking down of Fascist legislation and the upholding of constitutional rights and freedoms the country experienced a transition from an “uncertain” democracy (that was the case in Italy in 1956) to a “mature” democracy. The role of the constitutional court also needs to be assessed in light of the fact that in most cases it was required to take decisions in conflict with the prevailing conservative stance of the government, the parliamentary majority, and the superior courts.
Chapter 3 deals with the Spanish Constitutional Court. In this second generation of constitutional courts there are fewer unknown factors and more instances of courts in other countries to draw inspiration from, including the Italian Constitutional Court. All this contributed to the establishment and consolidation of constitutional justice. In the period from 1980 to the early 1990s, the Spanish Court dealt with four main issues, concerning the normative value of the constitutional provisions, the preconstitutional legislation, fundamental rights, and the territorial organization of the state. From the very beginning, the constitutional court upheld the normative value of all the provisions of the Constitution, and played an important role in determining whether the preconstitutional laws were in conflict with the provisions of the Constitution laying down fundamental rights and freedoms. Moreover, it succeeded in setting up an effective system of protection of fundamental rights, as well as ensuring a rational functioning of the State of Autonomies. The territorial question represented one of the most complex issues to be addressed, and the outcome of the transition to democracy was largely dependent on this matter.
This chapter introduces stochastic differential equations (SDEs) from the computational point of view, starting with several examples to illustrate the computational definition of the SDE that is used throughout the book. The Fokker–Planck and Kolmogorov backward equations are then derived and their consequences presented. They are used to compute the mean transition time between favourable states of SDEs. The SDE formalism is then applied to a chemical system by deriving the chemical Fokker–Planck equation and the corresponding chemical Langevin equation. They are used to further analyse the chemical systems from Chapter 2, including the system with multiple favourable states and the self-induced stochastic resonance.
The second chapter, “Early Change,” explores what is known about environments in which intestinal disease transmission emerged. It marshals research in the biological sciences to discuss the settings in which early communities were able to transmit some intestinal pathogens and parasites, long before the agricultural revolution. It suggests that the construct of the “first epidemiological transition” needs to be revised. It explores the patterns of vulnerability to infectious intestinal disease associated with hunting, gathering, and fishing in an early era and those associated with early farming practices, settlements, and pastoral nomadism. It provides a historical overview of the evolution of zones of infectious intestinal disease, the various Eurasian attitudes toward human waste, regional patterns in the use or non-use of human excreta in early agriculture, and early urban sanitation.
In this paper, I investigate the conditional contributions of the ins and outs of unemployment from both empirical and theoretical perspectives. Based on a New Keynesian Dynamic Stochastic General Equilibrium (DSGE) theoretical framework, I estimate a sign restriction Vector Auto Regressive (VAR) model using French data. To identify the origins of unemployment dynamics in terms of worker transition rates, I simulate two shocks: one on the supply side (technology) and the other on the demand side (monetary). The VAR model reveals that the contributions of transition rates in explaining unemployment differ across shocks. After a technology shock, unemployment fluctuations are mainly explained by the job finding process, while the contributions of the two margins are more balanced for the monetary shock. The theoretical model is not able to reproduce the underlying mechanisms inducing unemployment. In particular, the conditional contributions of the job separation margin are overestimated each time. For instance, after a technology shock, 60% of unemployment changes are generated by this margin, while the data suggest a contribution of 28%. This paper strongly indicates that, in its standard formulation, a search and matching DSGE model featuring endogenous job separations is not able to replicate the dominating influence of the outflow process.
Despite the much improved therapeutic approaches for cancer treatment that have been developed over the past 50 years, cancer remains a major cause of mortality globally. Considerable epidemiological and experimental evidence has demonstrated an association between ingestion of food and nutrients with either an increased risk for cancer or its prevention. There is rising interest in exploring agents derived from natural products for chemoprevention or for therapeutic purposes. Honey is rich in nutritional and non-nutritional bioactive compounds, as well as in natural antioxidants, and its potential beneficial function in human health is becoming more evident. A large number of studies have addressed the anti-cancer effects of different types of honey and their phenolic compounds using in vitro and in vivo cancer models. The reported findings affirm that honey is an agent able to modulate oxidative stress and has anti-proliferative, pro-apoptotic, anti-inflammatory, immune-modulatory and anti-metastatic properties. However, despite its reported anti-cancer activities, very few clinical studies have been undertaken. In the present review, we summarise the findings from different experimental approaches, including in vitro cell cultures, preclinical animal models and clinical studies, and provide an overview of the bioactive profile and bioavailability of the most commonly studied honey types, with special emphasis on the chemopreventive and therapeutic properties of honey and its major phenolic compounds in cancer. The implications of these findings as well as the future prospects of utilising honey to fight cancer will be discussed.
We introduce an idealised model for overland flow generated by rain falling on a hillslope. Our prime motivation is to show how the coalescence of runoff streams promotes the total generation of runoff. We show that, for our model, as the rate of rainfall increases in relation to the soil infiltration rate there is a distinct phase change. For low rainfall (the subcritical case) only the bottom of the hillslope contributes to the total overland runoff, while for high rainfall (the supercritical case) the whole slope contributes and the total runoff increases dramatically. We identify the critical point at which the phase change occurs, and show how it depends on the degree of coalescence. When there is no stream coalescence the critical point occurs when the rainfall rate equals the average infiltration rate, but when we allow coalescence the critical point occurs when the rainfall rate is less than the average infiltration rate, and increasing the amount of coalescence increases the total expected runoff.
Experiments of a turbulent mixing zone created by the Faraday instability at the statically stable interface between salt and fresh water are presented. The two-layer system, contained in a cuboidal tank of large dimensions, is accelerated vertically and periodically at various frequencies and amplitudes for three different density contrasts. We have developed a linear approach accounting for the full inhomogeneous and viscous problem, that is applied to a linear piecewise background density profile, and recovers the limiting cases of interface and homogeneous turbulence with a fully developed mixing layer. At onset, the wavelength of the most amplified modes and the corresponding Floquet exponent of the interface both verify our predictions. The dynamics is rather different when the instability is triggered from a sharp or diffuse interface: in the latter case, a change of characteristic wavelengths can be observed experimentally and explained by the theory. In the turbulent regime, the time evolution of the mixing zone size
for various experimental configurations compares well with confined direct numerical simulations. For some initial conditions, a short harmonic response of the instability is observed before the usual subharmonic one. Finally, the ultimate size of the mixing layer
, measured with a probe after the saturation of the instability and end of the forcing, is in excellent agreement with the recent theoretical prediction
is the gravitational acceleration,
the Atwood number,
the frequency and
the acceleration ratio.
In this chapter, the private and public roles of memorial architecture are addressed in respect to three relevant topics: collective remembrance and competing memories, the process of bereavement, and the possibilities of architecture as an element of agency in remembering and dealing with a difficult past. Since rituals are articulated through space, the investigation then turns towards a distinction of underlining spatial concepts that are essential in modern memorial architecture. The commemorative potential of cemeteries and landscapes is explored in a brief analysis of the symbolic language and transitional qualities of both funerary and memorial architecture.
This article examines changes in Tunisian political and societal life that allowed the country's second attempt at political opening (beginning in 2011) to introduce deeper, more long-lasting changes in its political system as compared to the first attempt (beginning in 1987).1 The article argues that three such changes in particular—the increased role of regime moderates; the development of a network of civil society groups and political activists; and the use of inclusion, negotiation, and consensus—allowed the second attempt to unfold differently. The article also briefly discusses developments in the international context between the two attempts. The article contributes to existing studies of regime change and political transition as well as to historical considerations of Tunisian political developments more broadly.
This work deals with the closed-loop control of streaky structures induced by free-stream turbulence (FST), at the levels of 3.0 % and 3.5 %, in a zero-pressure-gradient transitional boundary layer, by means of localized sensors and actuators. A linear quadratic Gaussian regulator is considered along with a system identification technique to build reduced-order models for control. Three actuators are developed with different spatial supports, corresponding to a baseline shape with only vertical forcing, and to two other shapes obtained by different optimization procedures. A computationally efficient method is derived to obtain an actuator that aims to induce the exact structures that are inside the boundary layer, given in terms of their first spectral proper orthogonal decomposition (SPOD) mode, and an actuator that maximizes the energy of induced downstream structures. All three actuators lead to significant delays in the transition to turbulence and were shown to be robust to mild variations in the FST levels. Integrated total drag reductions observed were up to 21 % and 19 % for turbulence intensity levels of 3.0 % and 3.5 %, respectively, depending on the considered actuator. Differences are understood in terms of the SPOD of actuation and FST-induced fields along with the causality of the control scheme when a cancellation of disturbances is considered along the wall-normal direction. The actuator optimized to generate the leading downstream SPOD mode, representing the streaks in the open-loop flow, leads to the highest transition delay, which can be understood due to its capability of closely cancelling structures in the boundary layer.
The current work presents a realizable method to control streaky disturbances in boundary layer flows and delay transition to turbulence by means of active flow control. Numerical simulations of the nonlinear transitional regime in a Blasius boundary layer are performed where streaks are excited in the boundary layer by means of a high level of free-stream turbulence. The occurring disturbances are measured by means of localized wall-shear-stress sensors and damped out using near-wall actuators, which resemble ring plasma actuators. Each actuator is powered by a time-varying signal whose amplitude is computed by processing signals from the sensors. The processed signal is the result of two control laws: the linear quadratic Gaussian regulator (LQG) and the inverse feed-forward control technique (IFFC). The use of the first control method, LQG, requires a state-space representation of the system dynamics, so the flow is described by means of a linear time-invariant operator that captures only the most relevant information of the dynamics and results in a reduced-order model (ROM). The ROM is computed by means of the eigensystem realization algorithm (ERA), which is based on the impulse responses of the real system. Collecting such impulse responses may be unfeasible when considering free-stream turbulence because of the high dimensionality of the input forcing needed for a precise description of such a phenomenon. Here, a new method to identify the relevant system dynamics and generate the needed impulse responses is proposed, based on additional shear-stress measurements in an upstream location. Transfer functions between such measurements and other downstream sensors are obtained and allow the derivation of the ERA system, in a data-driven approach that would be realizable in experiments. Finally, in order to discuss the advantages of the LQG based on the ROM and analyse its performance, the implemented LQG is compared to the IFFC, which consists of wave cancellation. The work (i) presents a systematic and straightforward way to deal with high-dimensional disturbances in order to build ROMs for a feasible control technique, and (ii) shows that even when considering practical constraints, such as the type and size of actuators and sensors, it is possible to achieve at least as large delay of bypass transition as that obtained in more idealized cases found in the literature.
This paper focuses on robust control of a simplest passive model, which is established on a DCLF (discrete control Lyapunov function) -based control system, and presents gait transition method based on the study of purely passive walker. Firstly, the DCLF is introduced to stabilize walking process between steps exponentially by modulating the length of next step. Next, the swing leg trajectory from mid-stance position to foot-strike can be planned. Then the control law is calculated to resist external disturbance. Besides, an impulse is added just before foot-strike to realize a periodic walking pattern on flat or uphill ground. With walking terrain varying, the robot can transit to an adaptive walking gait in a few steps. With different push or pull disturbances acting on hip joint and the robot gait transiting on a continuously slope-changing downhill, the effectiveness of the presented DCLF-based method is verified using simulation experiments. The ability to walk on a changing environment is also presented by simulation results. The insights of this paper can help to develop a robust control method and adaptive walking of dynamic passive locomotion robots.
The transition to turbulence in pipe flow proceeds through several distinct stages, eventually producing aggressively expanding regions of fluctuations, ‘slugs’, surrounded by laminar flow. By examining mean-velocity profiles, fluctuating-velocity profiles and Reynolds stress profiles, the seminal study of Wygnanski & Champagne (J. Fluid Mech., vol. 59 (2), 1973, 281–335) concluded that the flow inside slugs is ‘identical’ to fully turbulent flow. Although this conclusion is widely accepted, upon closer examination of their analysis, we find that their data cannot be used to substantiate this conclusion. We resolve this conflict via new experiments and simulations wherein we pair slugs and fully turbulent flow at the same value of Reynolds number (
). We conclude that the flow inside a slug is indeed indistinguishable from a fully turbulent flow but only when the two flows share the same value of
. Our work highlights the rich
-dependence of transitional pipe flows.
This article attempts to identify the main ‘above-ground’ factors which impact on the contribution that geothermal energy can make to the Dutch Energy Transition, and to draw conclusions about these factors. Recent literature sources are used to illustrate the size of Dutch heating demand, and the part of this which can be provided by geothermal energy. Consideration is given to the impact of off-take variability over time, showing that the base-load nature of geothermal doublets acts as a restraint on the share which they can take in the energy supply. The characteristics of district heating grids are discussed. Other potential sources of heat are considered and compared.
The conclusion is that geothermal energy can provide a material contribution to the energy transition. This depends to a large extent on the existence of and design choices made for the development of district heating networks. Large size and standardisation, and the development of seasonal heat storage, are beneficial.
Unlike most other renewable sources of heat, which have alternative ‘premium’ applications such as the provision of ‘peak capacity’ or molecules for feedstock, geothermal energy is not suitable for other uses. The emission savings that it can provide will be lost if other heat sources are chosen in preference as supply for district heating, so that it makes sense that district heating infrastructure should be designed to encourage the use of geothermal energy where possible.
In this work, we carried out direct numerical simulations in large channel domains and studied the kinematics and dynamics of fully localised turbulent bands at Reynolds number
. Our results show that the downstream end of the band features fast streak generation and travels into the adjacent laminar flow, whereas streaks at the upstream end decay continually and more slowly. This asymmetry is responsible for the transverse growth of the band. We particularly investigated the mechanism of streak generation at the downstream end, which drives the growth of the band. We identified a spanwise inflectional instability associated with the local mean flow near the downstream end, and our results strongly suggest that this instability is responsible for the streak generation and ultimately for the growth of the band. Based on our study, we propose a possible self-sustaining mechanism of fully localised turbulent bands at low Reynolds numbers in channel flow.
The Ordovician–Silurian (O–S) transition was a critical interval in geological history. Multiple geochemical methods are used to explore the changes in oceanic environment. The Nd isotopic compositions in the Yangtze Sea are controlled by two sources: the continental erosion and the Panthalassa Ocean. High εNd(t) values during the Katian, late Hirnantian and Rhuddanian intervals are associated with the high sea level, which resulted in less terrestrial input based on the low Ti/Al and Zr/Al ratios. In contrast, low εNd(t) values during the early Hirnantian interval are related to the sea-level fall; in this case, the exposure of submarine highs and the growth of Yangtze Oldlands could lead to more continental materials being transported into the Yangtze Sea based on high Ti/Al and Zr/Al ratios. In addition, the negative εNd(t) excursion can also be attributed to the weak circulation between the Yangtze Sea and Panthalassa Ocean when sea level was low. Furthermore, the sea-level eustacy plays a significant role in the changes in redox water conditions. The redox indices, mainly UEF, Ce/Ce* and Corg/PT, across the O–S transition show a predominance of anoxic ocean over the Yangtze Sea during the Katian, late Hirnantian and Rhuddanian intervals, and an oxygenated episode was briefly introduced during the early Hirnantian period because of the fall in sea level. The Late Ordovician biotic crisis was marked by two-phase extinction events, and the change in sea level and redox chemistry may be the important kill mechanisms.