Academic literature on the topic 'Internal forcing'

AbstractThe Atlantic multidecadal variability (AMV) modulates various climate features worldwide with enormous societal and economic implications, including variations in hurricane activity in the Atlantic, sea level, West African and Indian monsoon rainfall, European climate, and hemispheric-scale surface temperature. Leading hypotheses regarding the nature and origin of AMV focus primarily on its links with oceanic and coupled ocean–atmosphere internal variability, and on its response to external forcing. The role of another possible process, that of atmospheric noise forcing of the ocean, has received less attention. This is addressed here by means of historical coupled simulations and diagnostic experiments, which isolate the influences of external and atmospheric noise forcings. Our findings show that external forcing is an important driver of the simulated AMV. They also demonstrate that weather noise is key in driving the simulated internal AMV in the southern part (0°–60°N) of the AMV region, and that weather noise forcing is responsible for up to 10%–20% of the multidecadal internal SST variability in some isolated areas of the subpolar gyre region. Ocean dynamics independent from the weather noise forcing is found to be the dominant cause of multidecadal SST in the northern part of the AMV region.

The motion of an initially quiescent, incompressible, stratified and/or rotating uid of semi-infinite extent due to surface forcing is considered. The stratification parameter N and the Coriolis parameter f are constant but arbitrary and all possible combinations are considered, including N = 0 (rotating homogeneous fluid), f = 0 (non-rotating stratified fluid) and the special case N = f. The forcing is suction or pumping at an upper rigid surface and the response consists of geostrophic flows and inertial-internal waves. The response to impulsive point forcings (Green's functions) is contrasted with the response to finite-sized circularly symmetric impulsive forcings. Early-time and large-time behaviour are studied in detail. At early times transient internal waves change the vortices that are created by pumping/suction at the surface. The asymptotically remaining vortices are determined, a simple expression for what fraction of the initial energy is converted into internal waves is derived, as well as wave energy fluxes and the dependence of the flux direction on the value of N/f. The internal wave field is to leading order in time a distinct pulse, and rules for the arrival time of the pulse, its amplitude, its motion along a ray of constant frequency and decay with time, are given for the far field. A simple formula for the total wave energy distribution as a function of frequency is derived for when all waves have propagated away from the forcing.

Abstract This paper considers the effect of time-dependent lower boundary wave forcing on the internal variability found to appear spontaneously in a stratosphere-only model when the forcing is perfectly steady. While the time-dependent forcing is found to modulate the internal variability, leading in some cases to frequency locking of the upper-stratospheric response to the forcing, the temporal and spatial structure of the variability remains similar to the case when the forcing is time independent. Experiments with a time-periodic modulation of the forcing amplitude indicate that the wave flux through the lower boundary is only partially related to the instantaneous forcing, but is more significantly influenced by the condition of the polar vortex itself. In cases of purely random wave forcing with zero time mean, the stratospheric response is similar to that obtained with steady forcing of magnitude equal to the root-mean-square of the time-varying forcing.

Abstract Changes in Earth’s climate are influenced by internal climate variability and external forcings, such as changes in solar radiation, volcanic eruptions, anthropogenic greenhouse gases (GHG), and aerosols. Although the response of surface temperature to external forcings has been studied extensively, this has not been done for sea level. Here, a range of climate model experiments for the twentieth century is used to study the response of global and regional sea level change to external climate forcings. Both the global mean thermosteric sea level and the regional dynamic sea level patterns show clear responses to anthropogenic forcings that are significantly different from internal climate variability and larger than the difference between models driven by the same external forcing. The regional sea level patterns are directly related to changes in surface winds in response to the external forcings. The spread between different realizations of the same model experiment is consistent with internal climate variability derived from preindustrial control simulations. The spread between the different models is larger than the internal variability, mainly in regions with large sea level responses. Although the sea level responses to GHG and anthropogenic aerosol forcing oppose each other in the global mean, there are differences on a regional scale, offering opportunities for distinguishing between these two forcings in observed sea level change.

Abstract This paper examines the nature and robustness of internal stratospheric variability, namely the variability resulting from the internal dynamics of the stratosphere itself, as opposed to that forced by external sources such as the natural variability of the free troposphere. Internal stratospheric variability arises from the competing actions of radiative forcing, which under perpetual winter conditions strengthens the polar vortex, and planetary wave breaking, which weakens it. The results from a stratosphere-only model demonstrate that strong internal stratospheric variability, consisting of repeated sudden warming-type events, exists over a wide range of realistic radiative and wave forcing conditions, and is largely independent of other physical and numerical parameters. In particular, the coherent form of the variability persists as the number of degrees of freedom is increased, and is therefore not an artifact of severe model truncation. Various diagnostics, including three-dimensional representations of the potential vorticity, illustrate that the variability is determined by the vertical structure of the vortex and the extent to which upward wave propagation is favored or inhibited. In this paper, the variability arising from purely internal stratosphere dynamics is isolated by specifying thermal and wave forcings that are completely time independent. In a second paper, the authors investigate the relative importance of internal and external variability by considering time-dependent wave forcing as a simple representation of tropospheric variability.

The near-resonant flow of a stratified fluid through a localized contraction is considered in the long-wavelength weakly nonlinear limit to investigate the transient development of nonlinear internal waves and whether these might lead to local steady hydraulic flows. It is shown that under these circumstances the response of the fluid will fall into one of three categories, the first governed by a forced Korteweg–de Vries equation and the latter two by a variable-coefficient form of this equation. The variable-coefficient equation is discussed using analytical approximations and numerical solutions when the forcing is of the same (positive) and of opposite (negative) polarity to that of free solitary waves in the fluid. For positive and negative forcing, strong and weak resonant regimes will occur near the critical point. In these resonant regimes for positive forcing the flow becomes locally steady within the contraction, while for negative forcing it remains unsteady within the contraction. The boundaries of these resonant regimes are identified in the limits of long and short contractions, and for a number of common stratifications.

This paper presents the results from an experimental investigation into the planar, multi-mode response of a metallic portal frame to a harmonic support excitation. Forcing frequency and amplitude sweeps near the frequencies of the eighth and tenth modes of the structure revealed multi-mode responses. In the frequency interval surrounding that of the eighth mode, two additional lower-frequency modes, the fourth and the sixth, were excited. The mechanism responsible for the multimode behaviour of the frame is a combination internal resonance of the additive type. In addition, for a brief interval, a non-resonant interaction involving the eighth mode and the first mode was observed. Forcing amplitude sweeps for forcing frequencies below the eighth linear natural frequency produced a saturation-type phenomenon and a chaotically modulated motion. For the frequency interval surrounding that of the tenth mode, the response contained contributions from seven modes; these modes were excited through the simultaneous satisfaction of several internal resonance conditions.

Abstract. Aerosols and their precursors are emitted abundantly by transport activities. Transportation constitutes one of the fastest growing activities and its growth is predicted to increase significantly in the future. Previous studies have estimated the aerosol direct radiative forcing from one transport sub-sector, but only one study to our knowledge estimated the range of radiative forcing from the main aerosol components (sulphate, black carbon (BC) and organic carbon) for the whole transportation sector. In this study, we compare results from two different chemical transport models and three radiation codes under different hypothesis of mixing: internal and external mixing using emission inventories for the year 2000. The main results from this study is a positive direct radiative forcing for aerosols emitted by road traffic of +20±11 mWm−2 for an externally mixed aerosol, and of +32±13 mWm−2 when BC is internally mixed . These direct radiative forcings are much higher than the previously published estimate of +3±11 mWm−2. For transport activities from shipping, the net direct aerosol radiative forcing is negative. This forcing is dominated by the contribution of the sulphate. For both an external and an internal mixture, the radiative forcing from shipping is estimated at −26±4 mWm−2. These estimates are in very good agreement with the range of a previously published one (from −46 to −13 mWm−2) but with a much narrower range. By contrast, the direct aerosol forcing from aviation is estimated to be small, and in the range −0.9 to +0.3 mWm−2.

The Southern Ocean is governed by strong wind forcing, energetic eddies and probably intense internal wave fields, which are considered to be generated in part by interaction of the eddy field with bottom topography. While wind and eddy forcing have been recognized in the dynamical balance of the Southern Ocean Meridional Overturning Circulation (MOC), the role of internal waves remains uncertain. The present study aims to investigate the extent to which the interaction of an energetic eddy field with realistic bottom topography, leading to diabatic forcing of the interior stratification through internal wave breaking, can sustain a deep overturning circulation and provide an additional leading order term in the Southern Ocean MOC that is unaccounted for by current theories and numerical models. A hierarchy of experiments to test this hypothesis is conducted in this thesis. The MIT General Circulation Model (MITgcm) is configured to simulate a circumpolar current in two individual versions of a zonal channel, namely a coarse-resolution setup with Gent-McWilliams eddy parameterisation and a mesoscale eddy-resolving setup. The energy input that arises from internal wave breaking and forces the buoyancy budget of the MOC is parameterised in the model via a vertical diffusivity profile. Initially forced to follow a simple constant shape, this diffusivity profile is subsequently estimated online via the internal lee wave energy generation rate, which is calculated from the model stratification, velocities and from prescribed sub-grid-scale topography, following nonlinear internal lee wave theory. Results from the individual experiments are discussed in view of the extent and mechanisms by which internal waves generated by eddy-topography interaction force the cross-channel MOC. The main results of this thesis show that the internal lee wave energy generation rate enhances the diapycnal diffusivity near the bottom, which results in a substantial increase in the strength of the residual MOC of the lower limb and a warming of the deep interior of the channel.

The profound simplicity and versatility of the molecule at the heart of all earth- bound life forms, DNA, continues to inspire new frontiers of scientific inquiry. Central to many of these, including the de novo design of novel DNA nanostructures and the use of DNA to probe the principles of biological self-assembly and the operation of cellular nanomachines, is the interaction of DNA with forces, both internal and external. This thesis comprises a survey of three key ways coarse-grained simulations using the oxDNA model can contribute to efforts to characterize these interactions. First, a non-equilibrium data analysis framework based on the Jarzynski equality from statistical physics is validated for use with oxDNA through the reconstruction of free energy landscapes for canonical DNA hairpin systems. We provide a framework for assessing errors in the method and apply it to study a system for which conventional equilibrium simulations would be impractical: DNA origami 'handles' proposed for use in force spectroscopy experiments. Next, we simulate the forcible unravelling of three DNA origami structures, the largest systems yet studied with simulated force spectroscopy. We combine these results with experimental AFM data to probe the mechanical response of origami in unprecedented detail, highlighting the effect of nanostructure design on unfolding behaviour. Lastly, we examine the validity of using widely-employed polymer elastic models to predict internal entropic forces in ssDNA. We develop a framework for measuring internal forces in the oxDNA coarse-grained model and apply it to analyze the pico-Newton range forces exerted by a recently proposed DNA origami force clamp, ultimately concluding that conventional means of estimating internal ssDNA forces are often inaccurate and should be supplemented with coarse-grained simulations. In addition to providing new insights about the DNA systems we present, our results highlight the significant fruits of complementing experimental studies with coarse-grained simulations.

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Includes bibliographical references (p. 227-253).
Human perception of sea fisheries has evolved from an inexhaustible resource paradigm towards a generalized concern on the degraded state of fish stocks and ecosystems. Accordingly, fisheries science and management are expanding from the traditional single-species approach towards an ecosystem approach to fisheries. Marine communities are organized as webs of interactions that are affected by external natural (climate) and anthropogenic (fishing) forcing, with their relative effects poorly known, but hypothesised to strongly depend on internal food web structure (i.e., who eats and controls whom). This thesis approaches relevant ecological considerations for an ecosystem approach to fisheries in the upwelling ecosystem off central Chile (33ºS-39ºS). The main objective is to assess the effects of internal (trophic structure) and external (fishing and environment) forcing factors at the fish stock and food web level in the study area. The methodology includes i) the construction of snapshot and dynamic food web models to test hypothesis of changes in the food web in the last century, and the relative contribution of fishing, trophic controls and bottom-up environmental variability to those changes, ii) the computation and analysis of a set of ecosystem indicators to test hypotheses of changes in different aspects of the exploited community (mean trophic level, age and length at maturity, network properties and system variability), iii) the analyses of the relationships between time series of abundance of species with known trophic interactions (Chilean hake-red squat lobster and Chilean hake-small pelagic fish) to test hypothesis of top-down and bottom-up control versus alternative hypotheses of fishing and/or environmental control in the same populations, and iv) simulation experiments to test hypotheses of ecosystem change and recovery under fishing and environmental forcing. Models and indicators are constructed using data series of abundance, catches, production, consumption and diets of the main functional groups in the study area. Snapshot and dynamic food web models are constructed and analyzed using the Ecopath with Ecosim software version 5.1 and routines therein. The observed trends in indicators and model results are in accordance with what is theoretically expected in stressed ecosystems (shift towards a food web dominated by short-lived, low trophic level and high turnover rate species), and suggest that the food web could be in a state that is more susceptible to external forcing. Fishing and the environment (bottom-up anomaly in PP) may have affected the upwelling ecosystem off central Chile both at the stock and at the food web level between 1970 and 2004. The effects of these forcing factors may have been mediated by trophic controls operating in the food web. There is also evidence to support the hypothesis that trophic controls beyond fishing, e.g., trophic (internal) and environment (external) may operate in the analysed populations and this information should be considered in their assessment and management. While target objectives are set and agreed, it is proposed that the main objective for the ecosystem approach to fisheries should be to avoid fishing-induced regime shifts, since results from simulation experiments suggest that fishing can induce ecosystem changes of lower recovery than bottom-up forcing.

In this thesis, using the principles of confirmatory factor analysis (CFA) and the cause-effect concept associated with structural equation modelling (SEM), a new flexible statistical framework for evaluation of climate model simulations against observational data is suggested. The design of the framework also makes it possible to investigate the magnitude of the influence of different forcings on the temperature as well as to investigate a general causal latent structure of temperature data. In terms of the questions of interest, the framework suggested here can be viewed as a natural extension of the statistical approach of 'optimal fingerprinting', employed in many Detection and Attribution (D&A) studies. Its flexibility means that it can be applied under different circumstances concerning such aspects as the availability of simulated data, the number of forcings in question, the climate-relevant properties of these forcings, and the properties of the climate model under study, in particular, those concerning the reconstructions of forcings and their implementation. It should also be added that although the framework involves the near-surface temperature as a climate variable of interest and focuses on the time period covering approximately the last millennium prior to the industrialisation period, the statistical models, included in the framework, can in principle be generalised to any period in the geological past as soon as simulations and proxy data on any continuous climate variable are available.  Within the confines of this thesis, performance of some CFA- and SEM-models is evaluated in pseudo-proxy experiments, in which the true unobservable temperature series is replaced by temperature data from a selected climate model simulation. The results indicated that depending on the climate model and the region under consideration, the underlying latent structure of temperature data can be of varying complexity, thereby rendering our statistical framework, serving as a basis for a wide range of CFA- and SEM-models, a powerful and flexible tool. Thanks to these properties, its application ultimately may contribute to an increased confidence in the conclusions about the ability of the climate model in question to simulate observed climate changes.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 3: Manuscript.

L’océan Indien est le lieu de processus atmosphériques et océaniques majeurs dont les répercussions en terme climatique peuvent être de grandes importances. Cette thèse se propose de documenter les forçages, les variabilités, les impacts et les interactions de la mousson Indo-asiatique et du courant des Aiguilles à l’échelle orbitale (incluant les conditions glaciaires-interglaciaires) au cours de la période Quaternaire.Si le maximum d’insolation (minimum de précession et maximum d’obliquité) initie les fortes moussons Indo-asiatiques, des forçages internes au système climatique jouent également un rôle majeur pour expliquer leur dynamique (fort vents et précipitations), en particulier le changement de volume de glace de l’hémisphère Nord et l’export de chaleur latente de l’océan Indien Sud. La prédominance de ces forçages internes est propre à la mousson Indo-asiatique et la distingue des moussons boréales Africaines. Ceci indique que le concept de mousson globale n’est pas valable à l’échelle orbitale.Concernant l’hémisphère Sud, les variations de température de surface du courant des Aiguilles exercent un contrôle important sur le climat Sud Africain (la végétation et les précipitations). Ce courant permet également le transfert plus ou moins important de chaleur et de sel vers l’océan Atlantique Sud par l’intermédiaire de la migration de la convergence subtropicale et des vents d’ouest associés. Ce mécanisme, contrôlé fortement par la dynamique des hautes latitudes Sud, affecte la circulation thermo-haline globale et constitue un acteur important des transitions glaciaires-interglaciaires et des changements de mode de variabilité climatique au cours du Quaternaire (Transition Mid-Pleistocène et évènement du Mid-Brunhes). Les changements induits dans le climat de l’Hémisphère Nord, et notamment le volume de glace, pourraient ensuite se répercuter sur la dynamique de la mousson. En revanche, l’effet des moussons sur le courant des Aiguilles parait mineur. Toutefois, les interactions entre la mousson Indo-asiatique, l’ENSO et les éventuels IOD (dipôles climatiques de l’océan Indien) pourraient affecter la dynamique du courant
The Indian Ocean is the place of major atmospheric and oceanic processes with large potential repercussions on the global climatic system. This thesis investigates forcing, variations, impacts and interactions of the Indo-Asian monsoon and of the Agulhas current at the orbital scale (including glacial-interglacial conditions) over the Quaternary period.Insolation maximum (precession minimum and obliquity maximum) initiates strong Indo-Asian monsoons, but processes internal to the climate system, in particular Northern Hemisphere (NH) ice volume changes and the latent heat export of the south Indian Ocean, play a major role to explain their dynamics (strongest winds and precipitation). The predominance of these internal forcings is a specificity of the Indo-Asian monsoon and distinguishes it from African boreal monsoons. This indicates that the concept of a global monsoon at the orbital scale is a misnomer.Concerning the Southern hemisphere, sea surface temperature variations of the Agulhas current exert an important control upon the South African climate (vegetation and precipitation). This current also participates to the transfer of heat and salt towards the South Atlantic Ocean whose intensity is mainly related to the migration of the subtropical convergence and associated westerlies winds. This mechanism, strongly controlled by high southern latitudes dynamics, affects the global overturning circulation and plays an important role for glacial-interglacial transitions and changes in modes of climate variability during the Quaternary (Mid-Pleistocene Transition and Mid-Brunhes event). Induced Northern hemisphere climate changes, in particular ice volume, could in turn influence monsoon dynamics. On the other hand, the effect of monsoons on the Agulhas current seems to be of minor importance. However, interactions between the Indo-Asian monsoon, ENSO and the possible IOD (Indian Ocean climatic Dipole) could affect the dynamic of the current

Near-resonant triad interactions and wave generation theory are investigated for continuously stratified fluids. Interaction equations are derived for spatially-varying wave trains under the inviscid Boussinesq approximation. Rotational effects are included, and properties of the underlying eigenvalue problem are explored. To facilitate a numerical study of the near-resonant interactions, numerical methods are developed and an analysis of wave generation on a periodic domain is performed. Numerical experiments using laboratory and ocean-scale parameters are conducted, and the simulations confirm the validity of the wave forcing theory. Interaction experiments demonstrate a strong tendency for waves to exhibit nonlinear behaviour. While resonant interactions are observed in the laboratory scale simulations, nonlinear steepening effects and the formation of solitary-like waves dominate the ocean-scale experiments. The results suggest that the weakly-nonlinear interaction theory is only appropriate in a limited parameter regime. The problem of analyzing forced wave equations on an infinite domain is also considered. Motivated by the results obtained on a periodic domain, asymptotic analysis is applied to three important wave equations. The method of steepest descents is used to determine the large-time behaviour for the linearized Korteweg-de Vries, Benjamin-Bona-Mahony, and internal gravity wave equations. The asymptotic results are compared with numerical experiments and found to agree to high precision.

This essay focuses on the ‘voice’ as it sounds in a specific type of recordings. This recordings always reproduce a poet performing a poem of his/her by reading it aloud. Nowadays this kind of recordings are quite common on Internet, while before the ’90 digital turn it was possible to find them only in specific collection of poetry books that came with a music cassette or a CD. These cultural objects, as other and more ancient analogic sources, were quite expensive to produce and acquire. However, all of them contain this same type of recoding which share the same characteristic: the author’s voice reading aloud a poem of his/her. By bearing in mind this specific cultural objet and its characteristics, this study aims to analyse the «intermedial relation» that occur between a poetic text and its recorded version with the author’s voice. This «intermedial relation» occurs especially when these two elements (text and voice) are juxtaposed and experienced simultaneously. In fact, some online archives dedicated to this type of recording present this configuration forcing the user to receive both text and voice in the same space and at the same time This specific configuration not just activates the intermedial relation, but also hybridises the status of both the reader, who become a «reader-listener», and the author, who become a «author-reader». By using an interdisciplinary approach that combines philosophy, psychology, anthropology, linguistics and cognitive sciences, the essay propose a method to «critically listening» some Spanish poets’ way of vocalising their poems. In addition, the book present Phonodia web archive built at the Ca’ Foscari University of Venice as a paradigmatic answer to editorial problems related to online multimedia archives dedicated to these specific recordings. An extent part of the book is dedicated to the twenty-eight interviews made to the Spanish contemporary poets who became part of Phonodia and agreed in discussing about their personal relation to ‘voice’ and how this element works in their creative practice.

This casenote reviews and discusses the series of decisions regarding sanctions imposed by the UN Security Council against Yassin Abdullah Kadi, as implemented in the EU legal order. In this series of cases, the EU Courts at different times take different positions regarding the relationship of the UN and the EU legal order, as well as their power to review EU acts implementing Security Council sanctions and (indirectly) the sanctions themselves. The series of cases marks a watershed moment in UN Security Council targeted sanctions, forcing EU member states to disobey them and eventually leading to the creation and strengthening of an internal UN review mechanism, the Office of the Ombudsperson.

Lifeline for about one-sixth of the world’s population in the subcontinent, the Indian summer monsoon (ISM) is an integral part of the annual cycle of the winds (reversal of winds with seasons), coupled with a strong annual cycle of precipitation (wet summer and dry winter). For over a century, high socioeconomic impacts of ISM rainfall (ISMR) in the region have driven scientists to attempt to predict the year-to-year variations of ISM rainfall. A remarkably stable phenomenon, making its appearance every year without fail, the ISM climate exhibits a rather small year-to-year variation (the standard deviation of the seasonal mean being 10% of the long-term mean), but it has proven to be an extremely challenging system to predict. Even the most skillful, sophisticated models are barely useful with skill significantly below the potential limit on predictability. Understanding what drives the mean ISM climate and its variability on different timescales is, therefore, critical to advancing skills in predicting the monsoon. A conceptual ISM model helps explain what maintains not only the mean ISM but also its variability on interannual and longer timescales.The annual ISM precipitation cycle can be described as a manifestation of the seasonal migration of the intertropical convergence zone (ITCZ) or the zonally oriented cloud (rain) band characterized by a sudden “onset.” The other important feature of ISM is the deep overturning meridional (regional Hadley circulation) that is associated with it, driven primarily by the latent heat release associated with the ISM (ITCZ) precipitation. The dynamics of the monsoon climate, therefore, is an extension of the dynamics of the ITCZ. The classical land–sea surface temperature gradient model of ISM may explain the seasonal reversal of the surface winds, but it fails to explain the onset and the deep vertical structure of the ISM circulation. While the surface temperature over land cools after the onset, reversing the north–south surface temperature gradient and making it inadequate to sustain the monsoon after onset, it is the tropospheric temperature gradient that becomes positive at the time of onset and remains strongly positive thereafter, maintaining the monsoon. The change in sign of the tropospheric temperature (TT) gradient is dynamically responsible for a symmetric instability, leading to the onset and subsequent northward progression of the ITCZ. The unified ISM model in terms of the TT gradient provides a platform to understand the drivers of ISM variability by identifying processes that affect TT in the north and the south and influence the gradient.The predictability of the seasonal mean ISM is limited by interactions of the annual cycle and higher frequency monsoon variability within the season. The monsoon intraseasonal oscillation (MISO) has a seminal role in influencing the seasonal mean and its interannual variability. While ISM climate on long timescales (e.g., multimillennium) largely follows the solar forcing, on shorter timescales the ISM variability is governed by the internal dynamics arising from ocean–atmosphere–land interactions, regional as well as remote, together with teleconnections with other climate modes. Also important is the role of anthropogenic forcing, such as the greenhouse gases and aerosols versus the natural multidecadal variability in the context of the recent six-decade long decreasing trend of ISM rainfall.

Nationalism: Past as Prologue began as a single volume being compiled by Ad Akande, a scholar from South Africa, who proposed it to me as co-author about two years ago. The original idea was to examine how the damaging roots of nationalism have been corroding political systems around the world, and creating dangerous obstacles for necessary international cooperation. Since I (Bruce E. Johansen) has written profusely about climate change (global warming, a.k.a. infrared forcing), I suggested a concerted effort in that direction. This is a worldwide existential threat that affects every living thing on Earth. It often compounds upon itself, so delays in reducing emissions of fossil fuels are shortening the amount of time remaining to eliminate the use of fossil fuels to preserve a livable planet. Nationalism often impedes solutions to this problem (among many others), as nations place their singular needs above the common good. Our initial proposal got around, and abstracts on many subjects arrived. Within a few weeks, we had enough good material for a 100,000-word book. The book then fattened to two moderate volumes and then to four two very hefty tomes. We tried several different titles as good submissions swelled. We also discovered that our best contributors were experts in their fields, which ranged the world. We settled on three stand-alone books:” 1/ nationalism and racial justice. Our first volume grew as the growth of Black Lives Matter following the brutal killing of George Floyd ignited protests over police brutality and other issues during 2020, following the police assassination of Floyd in Minneapolis. It is estimated that more people took part in protests of police brutality during the summer of 2020 than any other series of marches in United States history. This includes upheavals during the 1960s over racial issues and against the war in Southeast Asia (notably Vietnam). We choose a volume on racism because it is one of nationalism’s main motive forces. This volume provides a worldwide array of work on nationalism’s growth in various countries, usually by authors residing in them, or in the United States with ethnic ties to the nation being examined, often recent immigrants to the United States from them. Our roster of contributors comprises a small United Nations of insightful, well-written research and commentary from Indonesia, New Zealand, Australia, China, India, South Africa, France, Portugal, Estonia, Hungary, Russia, Poland, Kazakhstan, Georgia, and the United States. Volume 2 (this one) describes and analyzes nationalism, by country, around the world, except for the United States; and 3/material directly related to President Donald Trump, and the United States. The first volume is under consideration at the Texas A & M University Press. The other two are under contract to Nova Science Publishers (which includes social sciences). These three volumes may be used individually or as a set. Environmental material is taken up in appropriate places in each of the three books. * * * * * What became the United States of America has been strongly nationalist since the English of present-day Massachusetts and Jamestown first hit North America’s eastern shores. The country propelled itself across North America with the self-serving ideology of “manifest destiny” for four centuries before Donald Trump came along. Anyone who believes that a Trumpian affection for deportation of “illegals” is a new thing ought to take a look at immigration and deportation statistics in Adam Goodman’s The Deportation Machine: America’s Long History of Deporting Immigrants (Princeton University Press, 2020). Between 1920 and 2018, the United States deported 56.3 million people, compared with 51.7 million who were granted legal immigration status during the same dates. Nearly nine of ten deportees were Mexican (Nolan, 2020, 83). This kind of nationalism, has become an assassin of democracy as well as an impediment to solving global problems. Paul Krugman wrote in the New York Times (2019:A-25): that “In their 2018 book, How Democracies Die, the political scientists Steven Levitsky and Daniel Ziblatt documented how this process has played out in many countries, from Vladimir Putin’s Russia, to Recep Erdogan’s Turkey, to Viktor Orban’s Hungary. Add to these India’s Narendra Modi, China’s Xi Jinping, and the United States’ Donald Trump, among others. Bit by bit, the guardrails of democracy have been torn down, as institutions meant to serve the public became tools of ruling parties and self-serving ideologies, weaponized to punish and intimidate opposition parties’ opponents. On paper, these countries are still democracies; in practice, they have become one-party regimes….And it’s happening here [the United States] as we speak. If you are not worried about the future of American democracy, you aren’t paying attention” (Krugmam, 2019, A-25). We are reminded continuously that the late Carl Sagan, one of our most insightful scientific public intellectuals, had an interesting theory about highly developed civilizations. Given the number of stars and planets that must exist in the vast reaches of the universe, he said, there must be other highly developed and organized forms of life. Distance may keep us from making physical contact, but Sagan said that another reason we may never be on speaking terms with another intelligent race is (judging from our own example) could be their penchant for destroying themselves in relatively short order after reaching technological complexity. This book’s chapters, introduction, and conclusion examine the worldwide rise of partisan nationalism and the damage it has wrought on the worldwide pursuit of solutions for issues requiring worldwide scope, such scientific co-operation public health and others, mixing analysis of both. We use both historical description and analysis. This analysis concludes with a description of why we must avoid the isolating nature of nationalism that isolates people and encourages separation if we are to deal with issues of world-wide concern, and to maintain a sustainable, survivable Earth, placing the dominant political movement of our time against the Earth’s existential crises. Our contributors, all experts in their fields, each have assumed responsibility for a country, or two if they are related. This work entwines themes of worldwide concern with the political growth of nationalism because leaders with such a worldview are disinclined to co-operate internationally at a time when nations must find ways to solve common problems, such as the climate crisis. Inability to cooperate at this stage may doom everyone, eventually, to an overheated, stormy future plagued by droughts and deluges portending shortages of food and other essential commodities, meanwhile destroying large coastal urban areas because of rising sea levels. Future historians may look back at our time and wonder why as well as how our world succumbed to isolating nationalism at a time when time was so short for cooperative intervention which is crucial for survival of a sustainable earth. Pride in language and culture is salubrious to individuals’ sense of history and identity. Excess nationalism that prevents international co-operation on harmful worldwide maladies is quite another. As Pope Francis has pointed out: For all of our connectivity due to expansion of social media, ability to communicate can breed contempt as well as mutual trust. “For all our hyper-connectivity,” said Francis, “We witnessed a fragmentation that made it more difficult to resolve problems that affect us all” (Horowitz, 2020, A-12). The pope’s encyclical, titled “Brothers All,” also said: “The forces of myopic, extremist, resentful, and aggressive nationalism are on the rise.” The pope’s document also advocates support for migrants, as well as resistance to nationalist and tribal populism. Francis broadened his critique to the role of market capitalism, as well as nationalism has failed the peoples of the world when they need co-operation and solidarity in the face of the world-wide corona virus pandemic. Humankind needs to unite into “a new sense of the human family [Fratelli Tutti, “Brothers All”], that rejects war at all costs” (Pope, 2020, 6-A). Our journey takes us first to Russia, with the able eye and honed expertise of Richard D. Anderson, Jr. who teaches as UCLA and publishes on the subject of his chapter: “Putin, Russian identity, and Russia’s conduct at home and abroad.” Readers should find Dr. Anderson’s analysis fascinating because Vladimir Putin, the singular leader of Russian foreign and domestic policy these days (and perhaps for the rest of his life, given how malleable Russia’s Constitution has become) may be a short man physically, but has high ambitions. One of these involves restoring the old Russian (and Soviet) empire, which would involve re-subjugating a number of nations that broke off as the old order dissolved about 30 years ago. President (shall we say czar?) Putin also has international ambitions, notably by destabilizing the United States, where election meddling has become a specialty. The sight of Putin and U.S. president Donald Trump, two very rich men (Putin $70-$200 billion; Trump $2.5 billion), nuzzling in friendship would probably set Thomas Jefferson and Vladimir Lenin spinning in their graves. The road of history can take some unanticipated twists and turns. Consider Poland, from which we have an expert native analysis in chapter 2, Bartosz Hlebowicz, who is a Polish anthropologist and journalist. His piece is titled “Lawless and Unjust: How to Quickly Make Your Own Country a Puppet State Run by a Group of Hoodlums – the Hopeless Case of Poland (2015–2020).” When I visited Poland to teach and lecture twice between 2006 and 2008, most people seemed to be walking on air induced by freedom to conduct their own affairs to an unusual degree for a state usually squeezed between nationalists in Germany and Russia. What did the Poles then do in a couple of decades? Read Hlebowicz’ chapter and decide. It certainly isn’t soft-bellied liberalism. In Chapter 3, with Bruce E. Johansen, we visit China’s western provinces, the lands of Tibet as well as the Uighurs and other Muslims in the Xinjiang region, who would most assuredly resent being characterized as being possessed by the Chinese of the Han to the east. As a student of Native American history, I had never before thought of the Tibetans and Uighurs as Native peoples struggling against the Independence-minded peoples of a land that is called an adjunct of China on most of our maps. The random act of sitting next to a young woman on an Air India flight out of Hyderabad, bound for New Delhi taught me that the Tibetans had something to share with the Lakota, the Iroquois, and hundreds of other Native American states and nations in North America. Active resistance to Chinese rule lasted into the mid-nineteenth century, and continues today in a subversive manner, even in song, as I learned in 2018 when I acted as a foreign adjudicator on a Ph.D. dissertation by a Tibetan student at the University of Madras (in what is now in a city called Chennai), in southwestern India on resistance in song during Tibet’s recent history. Tibet is one of very few places on Earth where a young dissident can get shot to death for singing a song that troubles China’s Quest for Lebensraum. The situation in Xinjiang region, where close to a million Muslims have been interned in “reeducation” camps surrounded with brick walls and barbed wire. They sing, too. Come with us and hear the music. Back to Europe now, in Chapter 4, to Portugal and Spain, we find a break in the general pattern of nationalism. Portugal has been more progressive governmentally than most. Spain varies from a liberal majority to military coups, a pattern which has been exported to Latin America. A situation such as this can make use of the term “populism” problematic, because general usage in our time usually ties the word into a right-wing connotative straightjacket. “Populism” can be used to describe progressive (left-wing) insurgencies as well. José Pinto, who is native to Portugal and also researches and writes in Spanish as well as English, in “Populism in Portugal and Spain: a Real Neighbourhood?” provides insight into these historical paradoxes. Hungary shares some historical inclinations with Poland (above). Both emerged from Soviet dominance in an air of developing freedom and multicultural diversity after the Berlin Wall fell and the Soviet Union collapsed. Then, gradually at first, right wing-forces began to tighten up, stripping structures supporting popular freedom, from the courts, mass media, and other institutions. In Chapter 5, Bernard Tamas, in “From Youth Movement to Right-Liberal Wing Authoritarianism: The Rise of Fidesz and the Decline of Hungarian Democracy” puts the renewed growth of political and social repression into a context of worldwide nationalism. Tamas, an associate professor of political science at Valdosta State University, has been a postdoctoral fellow at Harvard University and a Fulbright scholar at the Central European University in Budapest, Hungary. His books include From Dissident to Party Politics: The Struggle for Democracy in Post-Communist Hungary (2007). Bear in mind that not everyone shares Orbán’s vision of what will make this nation great, again. On graffiti-covered walls in Budapest, Runes (traditional Hungarian script) has been found that read “Orbán is a motherfucker” (Mikanowski, 2019, 58). Also in Europe, in Chapter 6, Professor Ronan Le Coadic, of the University of Rennes, Rennes, France, in “Is There a Revival of French Nationalism?” Stating this title in the form of a question is quite appropriate because France’s nationalistic shift has built and ebbed several times during the last few decades. For a time after 2000, it came close to assuming the role of a substantial minority, only to ebb after that. In 2017, the candidate of the National Front reached the second round of the French presidential election. This was the second time this nationalist party reached the second round of the presidential election in the history of the Fifth Republic. In 2002, however, Jean-Marie Le Pen had only obtained 17.79% of the votes, while fifteen years later his daughter, Marine Le Pen, almost doubled her father's record, reaching 33.90% of the votes cast. Moreover, in the 2019 European elections, re-named Rassemblement National obtained the largest number of votes of all French political formations and can therefore boast of being "the leading party in France.” The brutality of oppressive nationalism may be expressed in personal relationships, such as child abuse. While Indonesia and Aotearoa [the Maoris’ name for New Zealand] hold very different ranks in the United Nations Human Development Programme assessments, where Indonesia is classified as a medium development country and Aotearoa New Zealand as a very high development country. In Chapter 7, “Domestic Violence Against Women in Indonesia and Aotearoa New Zealand: Making Sense of Differences and Similarities” co-authors, in Chapter 8, Mandy Morgan and Dr. Elli N. Hayati, from New Zealand and Indonesia respectively, found that despite their socio-economic differences, one in three women in each country experience physical or sexual intimate partner violence over their lifetime. In this chapter ther authors aim to deepen understandings of domestic violence through discussion of the socio-economic and demographic characteristics of theit countries to address domestic violence alongside studies of women’s attitudes to gender norms and experiences of intimate partner violence. One of the most surprising and upsetting scholarly journeys that a North American student may take involves Adolf Hitler’s comments on oppression of American Indians and Blacks as he imagined the construction of the Nazi state, a genesis of nationalism that is all but unknown in the United States of America, traced in this volume (Chapter 8) by co-editor Johansen. Beginning in Mein Kampf, during the 1920s, Hitler explicitly used the westward expansion of the United States across North America as a model and justification for Nazi conquest and anticipated colonization by Germans of what the Nazis called the “wild East” – the Slavic nations of Poland, the Baltic states, Ukraine, and Russia, most of which were under control of the Soviet Union. The Volga River (in Russia) was styled by Hitler as the Germans’ Mississippi, and covered wagons were readied for the German “manifest destiny” of imprisoning, eradicating, and replacing peoples the Nazis deemed inferior, all with direct references to events in North America during the previous century. At the same time, with no sense of contradiction, the Nazis partook of a long-standing German romanticism of Native Americans. One of Goebbels’ less propitious schemes was to confer honorary Aryan status on Native American tribes, in the hope that they would rise up against their oppressors. U.S. racial attitudes were “evidence [to the Nazis] that America was evolving in the right direction, despite its specious rhetoric about equality.” Ming Xie, originally from Beijing, in the People’s Republic of China, in Chapter 9, “News Coverage and Public Perceptions of the Social Credit System in China,” writes that The State Council of China in 2014 announced “that a nationwide social credit system would be established” in China. “Under this system, individuals, private companies, social organizations, and governmental agencies are assigned a score which will be calculated based on their trustworthiness and daily actions such as transaction history, professional conduct, obedience to law, corruption, tax evasion, and academic plagiarism.” The “nationalism” in this case is that of the state over the individual. China has 1.4 billion people; this system takes their measure for the purpose of state control. Once fully operational, control will be more subtle. People who are subject to it, through modern technology (most often smart phones) will prompt many people to self-censor. Orwell, modernized, might write: “Your smart phone is watching you.” Ming Xie holds two Ph.Ds, one in Public Administration from University of Nebraska at Omaha and another in Cultural Anthropology from the Chinese Academy of Social Sciences, Beijing, where she also worked for more than 10 years at a national think tank in the same institution. While there she summarized news from non-Chinese sources for senior members of the Chinese Communist Party. Ming is presently an assistant professor at the Department of Political Science and Criminal Justice, West Texas A&M University. In Chapter 10, analyzing native peoples and nationhood, Barbara Alice Mann, Professor of Honours at the University of Toledo, in “Divide, et Impera: The Self-Genocide Game” details ways in which European-American invaders deprive the conquered of their sense of nationhood as part of a subjugation system that amounts to genocide, rubbing out their languages and cultures -- and ultimately forcing the native peoples to assimilate on their own, for survival in a culture that is foreign to them. Mann is one of Native American Studies’ most acute critics of conquests’ contradictions, and an author who retrieves Native history with a powerful sense of voice and purpose, having authored roughly a dozen books and numerous book chapters, among many other works, who has traveled around the world lecturing and publishing on many subjects. Nalanda Roy and S. Mae Pedron in Chapter 11, “Understanding the Face of Humanity: The Rohingya Genocide.” describe one of the largest forced migrations in the history of the human race, the removal of 700,000 to 800,000 Muslims from Buddhist Myanmar to Bangladesh, which itself is already one of the most crowded and impoverished nations on Earth. With about 150 million people packed into an area the size of Nebraska and Iowa (population less than a tenth that of Bangladesh, a country that is losing land steadily to rising sea levels and erosion of the Ganges river delta. The Rohingyas’ refugee camp has been squeezed onto a gigantic, eroding, muddy slope that contains nearly no vegetation. However, Bangladesh is majority Muslim, so while the Rohingya may starve, they won’t be shot to death by marauding armies. Both authors of this exquisite (and excruciating) account teach at Georgia Southern University in Savannah, Georgia, Roy as an associate professor of International Studies and Asian politics, and Pedron as a graduate student; Roy originally hails from very eastern India, close to both Myanmar and Bangladesh, so he has special insight into the context of one of the most brutal genocides of our time, or any other. This is our case describing the problems that nationalism has and will pose for the sustainability of the Earth as our little blue-and-green orb becomes more crowded over time. The old ways, in which national arguments often end in devastating wars, are obsolete, given that the Earth and all the people, plants, and other animals that it sustains are faced with the existential threat of a climate crisis that within two centuries, more or less, will flood large parts of coastal cities, and endanger many species of plants and animals. To survive, we must listen to the Earth, and observe her travails, because they are increasingly our own.

Acoustic reciprocity is a property of linear, time invariant systems in which the locations of the source of a forcing and the received signal can be interchanged with no change in the measured response. This work investigates the breaking of acoustic reciprocity using a hierarchical structure consisting of internally-scaled masses coupled with cubically nonlinear springs. Using both direct results and variable transformations of numerical simulations, energy transmission is shown to occur in the direction of decreasing scale but not vice versa, constituting the breaking of acoustic reciprocity locally. When a linear spring connects the smallest scale of such a structure to the largest scale of another identical structure, an asymmetrical lattice is formed. Because of the scale mixing and transient resonance capture that occurs within each unit cell, it is demonstrated through further numerical experiments that energy transmission occurs primarily in the direction associated with the nonlinear coupling from the large to the small scale, thus signifying the breaking of reciprocity globally. This nonlinear hierarchical structure exhibits strong amplitude-dependency in which reciprocity-breaking is associated with specific ranges of excitation amplitudes for both impulse and harmonic forcing.

It is well known that soil plugging inside tubular steel piles will only appear in rather small diameter piles during impact driving. Therefore, large open ended steel piles, which are often used for the fixation of offshore buildings, such as wind farms, are highly unlikely to develop an internal soil plug. To take advantage of a soil plug, where a significant rise in the piles’ bearing capacity generally appears, a large diameter pipe-pile with an inner steel ring was designed by the third author. The location of the steel ring was determined by the soil formation in situ. To avoid increasing pile driving energy, the internal ring should dip into dense soil conditions only for the last few decimeters of driving. In October 2010, a full scale test was performed in the harbor of Hamburg, using two tubular piles with an outer diameter of 1220 mm. One pile was equipped with an inner steel ring as described above. The second pile was a typical tubular pile without any attached systems. To better compare the results, both piles were driven next to each other. Both piles were equipped with internal total stress and pore water pressure sensors at the pile tip to investigate the radial stress development during and after installation. Acceleration and strain at the pile head were measured to predict the bearing capacity. Using the numerical analysis program CAPWAP (Case Pile Wave Analysis Program) [15], the distribution of shaft and toe friction can be determined additionally. Furthermore, the internal soil movement was surveyed during driving. The results of the measurements showed, that when using an inner steel ring, a significant rise in internal radial stresses and the piles’ bearing capacity occurs. To better understand the stress development inside and outside the two investigated piles during driving, a numerical back-calculation of the recorded measurements was performed. The results of the full scale and numerical simulations, with a particular focus on the use of an internal steel ring to force the soil to plug behavior in large diameter pipe piles, is presented in the following paper.

Abstract Computational Fluid Dynamics (CFD) simulations are used to predict the flow-induced forcing in high-pressure multiphase pipe flow. Furthermore, empirical correlations from the literature is compared and validated against computational and experimental results. Based on the CFD results and in conjunction with the reference 6” (internal diameter (ID)) data, new scaling rules are proposed.

A methodology is presented for assessing internal flow-induced vibrations (FIV) in subsea piping systems. Finite Element (FE) models are constructed for the subject piping systems, including insulation, internal hydrocarbon weight and added mass of the surrounding sea water. Operating vibration data are measured using ROV-deployable accelerometer loggers clamped directly to the piping systems. The measured data are processed, analyzed and used for two purposes: model verification and dynamic response correlation. Modal parameters are extracted from the measured data and compared to the modal parameters computed from the structural FE model. The model is refined until the frequencies and mode shape errors are within the desired tolerance. The measured data are then used to derive a representative forcing function for use with frequency-domain random response analysis. The forcing function is derived such that the properties of the predicted vibration spectrum match those of the measured vibration spectrum for all measurement locations. The method presented herein provides a novel semi-empirical technique for calibrating FE models to make fatigue life predictions for subsea piping systems using measured vibration data.

We experimentally control the turbulent flow over backward-facing step (ReH = 31500). The goal is to modify the internal (Xr) and external (Lr) recirculation points and consequently the recirculation zone (Ar). A model-free machine learning control (MLC) is used as control logic. As benchmark, an optimized periodic forcing is employed. MLC generalizes periodic forcing by a multi-frequency actuation. In addition, a sensor-based control and a non-autonomous feedback, open- and closed-loop laws, were use to optimize the control. The MLC multi-frequency forcing outperforms, as expected, periodic forcing. The non-autonomous feedback brings a further improvement. The unforced and actuated flows have been investigated in real-time with a TSI particle image velocimetry (PIV) system. The current study shows that a generalization of multi-frequency forcing and sensor feedback significantly reduces the turbulent recirculation zone, far beyond optimized periodic forcing. The study suggests that MLC can effectively explore and optimize new feedback actuation mechanisms and we anticipate MLC to be a game changer in turbulence control.

The Reynolds-averaged Navier-Stokes equations were solved to predict the internal basin-scale wave motion in the south arm of the Great Salt Lake. Forcing of the wave motion was through surface stresses induced by a spatially uniform but temporally varying wind distribution. The brine distribution was initialized as an upper layer with salinity 120 ppt over a deep brine layer of salinity 240 ppt. The simulations were run for one month periods with wind data (from the Salt Lake City International Airport) for the months March, April, May, and June 2006. Results indicate the existence of a Kelvin wave propagating counter-clockwise about the perimeter of the basin with period 24 hours.

This paper examines internal sloshing motions in 2-D numerical wave tanks subjected to horizontal excitation. In all of the cases studied, the rectangular tank of liquid has a width-to-depth ratio of 2. The results presented are from simulations of internal waves induced by sloshing a density-stratified liquid. Non-linear, viscous flow equations of a Newtonian, Boussinesq liquid are solved. Some of the features of the evolution of sloshing in nearly two-layer and three-layer fluid systems are described. Initially, the middle of the two layers and the center of the middle layer of the three layers are horizontal and located at the center of the tank. The two-layer cases are forced at resonance. The evolution of sloshing from rest is examined. The maximum amplitude of sloshing occurs during the initial transient. If breaking occurs it is at the center of the container in the two-layer cases. The subharmonic forcing of a three-layer case induces a resonant response with the middle layer moving in such a way that motion is perpendicular to the isopycnals within this layer. These model problems provide some insights into the relatively complex sloshing that can occur in density-stratified liquids.

In this paper an oscillator with time delayed velocity feedback controls is studied in detail. The particular attention is focused on internal double-Hopf bifurcation with an external exciting force. Linear analysis is used to find the critical conditions under which a double-Hopf bifurcation occurs. Then center manifold theory is applied to obtain an ODE system described on a four-dimensional center manifold. Further, the technique of multiple-time scales is employed to find the approximate solutions of periodic and quasi-periodic motions. Finally, numerical simulation results are presented to verify the analytical predictions. Also, for some certain parameter values, numerical results show chaotic attractors.

Internal waves in the ocean occur in stably stratified fluids when a water parcel is vertically displaced by some external forcing and is restored by buoyancy forces. A specific case of such internal waves is internal tides and their associated currents. These currents can be significant in areas where internal waves degenerate into nonlinear solitary waves, known as solitons. Solitons are potentially hazardous for offshore engineering constructions, such as oil/gas pipelines and floating platforms. The most efficient mechanism of soliton generation is the tidal energy conversion from barotropic to baroclinic component over large-scale oceanic bottom obstructions (shelf breaks, seamounts, canyons and ridges). In this paper, a methodology is provided to compute diagnostics and prognostics for soliton generation and propagation, including the associated currents. The methodology comprises a diagnostic tool which, through the use of a set of theoretical and empirical formulations, selects areas where solitons are likely to occur. These theoretical and empirical formulations include the computation of the integral body force (1), the linear wave theory to compute the phase speed and the empirical model proposed by (2). After the selection procedure, the tool provides initial and boundary conditions for non-hydrostatic numerical models. The numerical models run in 2D-V configuration (vertical slices) with horizontal and vertical resolutions ranging from 50 to 200 m and 5 to 10 m, respectively. Examples are provided for an open ocean location over the Mascarene Plateau in the Indian Ocean. Validation of diagnostics and prognostics are provided against ADCP and satellite data.

The CREATE-AV™ Helios CFD simulation code has been used to accurately predict rotorcraft performance under a variety of flight conditions. The Helios package contains a suite of tools that contain almost the entire set of functionality needed for a variety of workflows. These workflows include tools customized to properly specify many in situ analysis and visualization capabilities appropriate for rotorcraft analysis. In situ is the process of computing analysis and visualization information during a simulation run before data is saved to disk. In situ has been referred to with a variety of terms including co-processing, covisualization, coviz, etc. In this paper we describe the customization of the pre-processing GUI and corresponding development of the Helios solver code-base to effectively implement in situ analysis and visualization to reduce file IO and speed up workflows for CFD analysts. We showcase how the workflow enables the wide variety of Helios users to effectively work in post-processing tools they are already familiar with as opposed to forcing them to learn new tools in order post-process in situ data extracts being produced by Helios. These data extracts include various sources of information customized to Helios, such as knowledge about the near- and off-body grids, internal surface extracts with patch information, and volumetric extracts meant for fast post-processing of data. Additionally, we demonstrate how in situ can be used by workflow automation tools to help convey information to the user that would be much more difficult when using full data dumps.

Economic theory is inconclusive regarding the effects of banning third-degree price discrimination under imperfect competition because they depend on how the competing firms rank their market segments. When, relative to uniform pricing, all competitors want higher prices in the same market segments, a ban on price discrimination will reduce profits and benefit some consumers at the expense of others. If, instead, some firms want to charge higher prices in segments where their competitors want to charge lower prices, price discrimination increases competition driving all prices down. In this case, forcing the firms to charge uniform prices can increase their profits and reduce consumer surplus. We use data on Colombian broadband subscriptions to estimate the demand for internet services. Estimated preferences and assumptions about competition are used to simulate a scenario in which firms lose their ability to price discriminate. Our results show large effects on consumer surplus and large effects on firms’ profits. Aggregate profits increase but the effects for individual firms are heterogeneous. The effects on consumer welfare vary by city. In most cities, a uniform price regime causes large welfare transfers from low-income households towards high-income households and in a few cities, prices in all segments rise. Poorer households respond to the increase in prices by subscribing to internet plans with slower download speed.