MAD Model Research Articles

Circular Polarization of Simulated Images of Black Holes

Models of the resolved Event Horizon Telescope (EHT) sources Sgr A* and M87* are constrained by observations at multiple wavelengths, resolutions, polarizations, and time cadences. In this paper, we compare unresolved circular polarization (CP) measurements to a library of models, where each model is characterized by a distribution of CP over time. In the library, we vary the spin of the black hole, the magnetic field strength at the horizon (i.e., both SANE and magnetically arrested disk or MAD models), the observer inclination, a parameter for the maximum ion–electron temperature ratio assuming a thermal plasma, and the direction of the magnetic field dipole moment. We find that Atacama Large Millimeter/submillimeter Array (ALMA) observations of Sgr A* are inconsistent with all edge-on (i = 90°) models. Restricting attention to the MAD models favored by earlier EHT studies of Sgr A*, we find that only models with magnetic dipole moment pointing away from the observer are consistent with ALMA data. We also note that in 26 of the 27 passing MAD models, the accretion flow rotates clockwise on the sky. We provide a table of the means and standard deviations of the CP distributions for all model parameters, along with their trends.

The Joker’s Shifting Face: Eighty Years of Mad History in Batman and American Culture

That “grim jester with a twisted brain,” Batman supervillain the Joker reflects shifting social constructions of mental difference in the US across eight decades. The article reads Batman serial comics, graphic novels, and film against four key moments in Mad History: eugenics, psychiatric survivor activism in the 1960s and 1970s, the trauma discourses of 1980s popular culture, and the criminalization of mental difference in the twenty-first century. Out of this complex conversation four models of madness are derived: toxic reproduction, liberation, mad genius, and the conflation of madness with violent crime. These models work intersectionally: Joker’s madness, queerness, and exceptionally white masculinity engender each other. Because of his distinctive qualities as a visual icon, he makes Mad History more visible, too.

The analysis of diversification properties of stablecoins through the Shannon entropy measure

The common goal for investors is to minimise the risk and maximise the returns on their investments. This is often achieved through diversification, where investors spread their investments across various assets. This study aims to use the MAD-entropy model to minimise the absolute deviation, maximise the mean return, and maximise the Shannon entropy of the portfolio. The MAD model is used because it is a linear programming model, allowing it to resolve large-scale problems and nonnormally distributed data. Entropy is added to the MAD model because it can better diversify the weight of assets in the portfolios. The analysed portfolios consist of cryptocurrencies, stablecoins, and selected world indices such as the SP500 and FTSE obtained from Yahoo Finance. The models found that stablecoins pegged to the US dollar, followed by stablecoins pegged to gold, are better diversifiers for traditional cryptocurrencies and stocks. These results are probably due to their low volatility compared to the other assets. Findings from this study may assist investors since the MAD-Entropy model outperforms the MAD model by providing more significant portfolio mean returns with minimal risk. Therefore, crypto investors can design a well-diversified portfolio using MAD entropy to reduce unsystematic risk. Further research integrating mad entropy with machine learning techniques may improve accuracy and risk management.

Flares in the Galactic centre – II. Polarization signatures of flares at mm-wavelengths

ABSTRACT Recent polarimetric mm-observations of the galactic centre showed sinusoidal loops in the $\mathcal {Q{\small --}U}$ plane with a duration of one hour. The loops coincide with a quasi-simultaneous X-ray flare. A promising mechanism to explain the flaring events are magnetic flux eruptions in magnetically arrested accretion flows (MAD). In our previous work, we studied the accretion flow dynamics during flux eruptions. Here, we extend our previous study by investigating whether polarization loops can be a signature produced by magnetic flux eruptions. We find that loops in the $\mathcal {Q{\small --}U}$ plane are robustly produced in MAD models as they lead to enhanced emissivity of compressed disc material due to orbiting flux bundles. A timing analysis of the synthetic polarized light curves demonstrate a polarized excess variability at time-scales of $\simeq 1~\rm h$. The polarization loops are also clearly imprinted on the cross-correlation of the Stokes parameters which allows us to extract a typical periodicity of $30~\rm min$ to $1~\rm h$ with some evidence for a spin dependence. These results are intrinsic to the MAD state and should thus hold for a wide range of astrophysical objects. A subset of general relativistic magnetohydrodynamic simulations without saturated magnetic flux, namely, single temperature standard and normal evolution models, also produces $\mathcal {Q{\small --}U}$ loops. However, in disagreement with the observations, loops in these simulations are quasi-continuous with a low polarization excess.

The ‘madness’ of accessing justice: legal mobilisation, welfare benefits and empowerment

ABSTRACT This article explores a paradigmatic case of legal mobilisation in the UK: successful litigation taken by RF, an anonymous claimant, against the Department of Work and Pensions’ cuts to disability mobility benefits for those facing ‘psychological distress’. While there is now a flourishing literature on the mobilisation of disability rights around the world, socio-legal scholarship has tended to overlook the mobilisation of law by those experiencing mental ill health or the potential contributions of adoption a social model of madness, mental distress and confusion. In developing a ‘thick description’ of the litigation process in the RF case, the article inductively identifies important lessons for scholars of legal consciousness and legal mobilisation. It showcases how the litigation process has both oppressive and empowering potential for those who are otherwise subject to systemic oppression by mental health and welfare benefit services. Second, it broadens the empirical literature on disability legal mobilisation which has largely overlooked the mobilisation of law by mental health service users and psychiatric survivors beyond issues related to psychiatric interventions, institutionalisation and detention.

Portfolio Optimization with a Mean-Absolute Deviation-Entropy Multi-Objective Model.

Investors wish to obtain the best trade-off between the return and risk. In portfolio optimization, the mean-absolute deviation model has been used to achieve the target rate of return and minimize the risk. However, the maximization of entropy is not considered in the mean-absolute deviation model according to past studies. In fact, higher entropy values give higher portfolio diversifications, which can reduce portfolio risk. Therefore, this paper aims to propose a multi-objective optimization model, namely a mean-absolute deviation-entropy model for portfolio optimization by incorporating the maximization of entropy. In addition, the proposed model incorporates the optimal value of each objective function using a goal-programming approach. The objective functions of the proposed model are to maximize the mean return, minimize the absolute deviation and maximize the entropy of the portfolio. The proposed model is illustrated using returns of stocks of the Dow Jones Industrial Average that are listed in the New York Stock Exchange. This study will be of significant impact to investors because the results show that the proposed model outperforms the mean-absolute deviation model and the naive diversification strategy by giving higher a performance ratio. Furthermore, the proposed model generates higher portfolio mean returns than the MAD model and the naive diversification strategy. Investors will be able to generate a well-diversified portfolio in order to minimize unsystematic risk with the proposed model.

Radiation GRMHD simulations of M87: funnel properties and prospects for gap acceleration

Abstract We use the public code ebhlight to carry out 3D radiative general relativistic magnetohydrodynamics (GRMHD) simulations of accretion on to the supermassive black hole in M87. The simulations self-consistently evolve a frequency-dependent Monte Carlo description of the radiation field produced by the accretion flow. We explore two limits of accumulated magnetic flux at the black hole (SANE and MAD), each coupled to several subgrid prescriptions for electron heating that are motivated by models of turbulence and magnetic reconnection. We present convergence studies for the radiation field and study its properties. We find that the near-horizon photon energy density is an order of magnitude higher than is predicted by simple isotropic estimates from the observed luminosity. The radially dependent photon momentum distribution is anisotropic and can be modeled by a set of point-sources near the equatorial plane. We draw properties of the radiation and magnetic field from the simulation and feed them into an analytic model of gap acceleration to estimate the very high energy (VHE) γ-ray luminosity from the magnetized jet funnel, assuming that a gap is able to form. We find luminosities of $\rm \sim 10^{41} \, erg \, s^{-1}$ for MAD models and $\rm \sim 2\times 10^{40} \, erg \, s^{-1}$ for SANE models, which are comparable to measurements of M87’s VHE flares. The time-dependence seen in our calculations is insufficient to explain the flaring behaviour. Our results provide a step towards bridging theoretical models of near-horizon properties seen in black hole images with the VHE activity of M87.

Four Gestures toward a Trans-Mad Aesthetic of Space

AbstractThis article argues for what the author calls a trans-mad aesthetic of space, defined as designs or artworks that embark, sense, emote, and collect, in ways that queerly disrupt the norms of the public sphere. These four aesthetic operations resist, in turn, four current affective/spatial norms of mental health treatment: confinement, rationality, repression, and an individualizing model of madness. As part of unfolding this model for a trans-mad aesthetic, the article asserts that the link between transgender and madness (as categories) is not merely one of addition—say, people who are both transgender and mad—but, rather, one of mutual constitution. To make these suggestions, the article engages an eccentric archive that includes posters that advocate transgender depathologization, Greek mythologies of gendered madness, government legislation about sexual sterilization, and psych ward design protocols. Its two key case studies, however, are artistic: Hannah Hull and James Leadbitter's “Madlove: A Designer Asylum” and the oeuvre of Montreal performance artist Coral Short.

The MAD Model of Moral Contagion: The Role of Motivation, Attention, and Design in the Spread of Moralized Content Online

With more than 3 billion users, online social networks represent an important venue for moral and political discourse and have been used to organize political revolutions, influence elections, and raise awareness of social issues. These examples rely on a common process to be effective: the ability to engage users and spread moralized content through online networks. Here, we review evidence that expressions of moral emotion play an important role in the spread of moralized content (a phenomenon we call moral contagion). Next, we propose a psychological model called the motivation, attention, and design (MAD) model to explain moral contagion. The MAD model posits that people have group-identity-based motivations to share moral-emotional content, that such content is especially likely to capture our attention, and that the design of social-media platforms amplifies our natural motivational and cognitive tendencies to spread such content. We review each component of the model (as well as interactions between components) and raise several novel, testable hypotheses that can spark progress on the scientific investigation of civic engagement and activism, political polarization, propaganda and disinformation, and other moralized behaviors in the digital age.

Doris Lessing, Antipsychiatry, and Bodies that Matter

In The Golden Notebook (1962), The Four-Gated City (1969), and Briefing for a Descent into Hell (1971), Doris Lessing examines the inadequacies of traditional models of madness and considers in their stead an antipsychiatric model championed by R. D. Laing. While ostensibly the three novels strive to conceive of madness in terms of Laing’s antipsychiatric thought, this article will argue that they in fact serve to reveal that Laing’s “lived body” (but gender-neutral) theory of schizophrenia failed to account for the discursively constructed, “inscribed” bodies of Lessing’s female characters. Lessing’s madness novels deconstruct Laing’s phallocentric approach to schizophrenia by rewriting his theory of madness as a gendered and embodied experience.

A low delay rate control method for screen content coding

Unlike conventional camera captured video (CCV), the screen content video (SCV) is generated by computer, like text, animation, or graphics. The SCV contents are discontinuous, as one abrupt frame is often followed by many static frames. These distinct characteristics bring challenges to the implementation of rate control in screen content coding (SCC). This paper proposes a low delay rate control method for SCC in HEVC (High Efficiency Video Coding). Firstly, a bit allocation scheme considering buffer status and picture complexity is proposed. Then, an R − MAD (Rate-Mean Absolute Difference)model is built to estimate frame QP (quantization parameter) according to allocated bits. Finally, a dynamical adjusting scheme is designed to fix the error of the estimated frame QP. Experimental results show that the proposed method could effectively avoid buffer overflow and improve the coding efficiency over the recommended rate control scheme in HEVC.

Stop Making Sense: The Politics of Aristophanic Madness

Abstract This paper discusses the use of madness in Aristophanic Comedy, and in particular how it is used as a means of evaluating and interrogating political interventions. The well-known theme of madness in Aristophanes’s Wasps provides the frame. Interpreting Philocleon’s madness has proved problematic because the complexity of comic madness has been under-estimated. Against negative models of madness that dominate in tragedy and in political discourse, madness in comedy can be not only a means of interrogating ideological and political norms, but also a constructive and even heroic form of behavior, which draws on epic and religious associations. Bdelycleon’s attempt to cure his father removes the positive substance and political value that anchors his father’s insanity, which leads to the aporetic finale.

Auto-Tuning for Solving Multi-Conditional MAD Model

Auto-Tuning for Solving Multi-Conditional MAD Model

Variability in GRMHD Simulations of Sgr : Implications for EHT Closure Phase Observations

Abstract Closure phases along different baseline triangles carry a large amount of information regarding the structures of the images of black holes in interferometric observations with the Event Horizon Telescope. We use long time span, high cadence, GRMHD+radiative transfer models of Sgr A* to investigate the expected variability of closure phases in such observations. We find that, in general, closure phases along small baseline triangles show little variability, except in the cases when one of the triangle vertices crosses one of the small regions of low visibility amplitude. The closure phase variability increases with the size of the baseline triangle, as larger baselines probe the small-scale structures of the images, which are highly variable. On average, the funnel-dominated MAD models show less closure phase variability than the disk-dominated SANE models, even in the large baseline triangles, because the images from the latter are more sensitive to the turbulence in the accretion flow. Our results suggest that image reconstruction techniques need to explicitly take into account the closure phase variability, especially if the quality and quantity of data allow for a detailed characterization of the nature of variability. This also implies that, if image reconstruction techniques that rely on the assumption of a static image are utilized, regions of the u–v space that show a high level of variability will need to be identified and excised.

Борьба сентиментальной, романтической и «натуральной» моделей безумия и её отражение в творчестве Ф.М. Достоевского

Борьба сентиментальной, романтической и «натуральной» моделей безумия и её отражение в творчестве Ф.М. Достоевского

Reflections on the social model of distress or madness: how to make the social model of disability accessible to people with mental health challenges

Purpose The purpose of this paper is to explore the relationships between recovery approaches and the social model of disability developed within the broader disability movement. Design/methodology/approach Personal narrative and reflective account written from the perspective of a senior peer trainer with reference to selected literature. Findings It is important to embrace a social model and rights-based approach within recovery approaches. Originality/value An original viewpoint on the perspective of a peer trainer linking recovery approaches to the social model and rights-based approach developed within the broader disability arena.

Grey system based novel forecasting and portfolio mechanism on CSE

Purpose – Because of the high volatility with unstable data patterns in the real world, the ability of forecasting price indices is notoriously embarrassing and represents a major challenge with traditional time series mechanisms; especially, most of the traditional approaches are weak to forecast future predictions in the high volatile and unbalanced frameworks under the global and local financial depressions. The purpose of this paper is to propose a new statistical approach for portfolio selection and stock market forecasting to assist investors as well as stock brokers to predict the future behaviors. Design/methodology/approach – This study mainly takes an attempt to understand the trends, behavioral patterns and predict the future estimations under the new proposed frame for the Colombo Stock Exchange (CSE), Sri Lanka. The methodology of this study is carried out under the two main phases. In the first phase, constructed a new portfolio mechanism based on k-means clustering. In the second stage, proposed a nonlinear forecasting methodology based on grey mechanism for forecasting stock market indices under the high-volatile fluctuations. The autoregressive integrated moving average (ARIMA) predictions are used as comparison mode. Findings – Initially, the k-mean clustering was applied to pick out the profitable sectors running under the CSE and results indicated that BFI is more significant than other 20 sectors. Second, the MAE, MAPE and MAD model comparison results clearly suggested that, the newly proposed nonlinear grey Bernoulli model (NGBM) is more appropriate than traditional ARIMA methods to forecast stock price indices under the non-stationary market conditions. Practical implications – Because of the flexible nonlinear modeling capability, proposed novel concepts are more suitable for applying in various areas in the field of financial, economic, military, geological and agricultural systems for pattern recognition, classification, time series forecasting, etc. Originality/value – For the large sample of data forecasting under the normality assumptions, the traditional time series methodologies are more suitable than grey methodologies. However, the NGBM is better both in model building and ex post testing stagers under the s-distributed data patterns with limited data forecastings.

Genomic prediction of crossbred performance based on purebred Landrace and Yorkshire data using a dominance model.

BackgroundIn pig breeding, selection is usually carried out in purebred populations, although the final goal is to improve crossbred performance. Genomic selection can be used to select purebred parental lines for crossbred performance. Dominance is the likely genetic basis of heterosis and explicitly including dominance in the genomic selection model may be an advantage when selecting purebreds for crossbred performance. Our objectives were two-fold: (1) to compare the predictive ability of genomic prediction models with additive or additive plus dominance effects, when the validation criterion is crossbred performance; and (2) to compare the use of two pure line reference populations to a single combined reference population.MethodsWe used data on litter size in the first parity from two pure pig lines (Landrace and Yorkshire) and their reciprocal crosses. Training was performed (1) separately on pure Landrace (2085) and Yorkshire (2145) sows and (2) the two combined pure lines (4230), which were genotyped for 38 k single nucleotide polymorphisms (SNPs). Prediction accuracy was measured as the correlation between genomic estimated breeding values (GEBV) of pure line boars and mean corrected crossbred-progeny performance, divided by the average accuracy of mean-progeny performance. We evaluated a model with additive effects only (MA) and a model with both additive and dominance effects (MAD). Two types of GEBV were computed: GEBV for purebred performance (GEBV) based on either the MA or MAD models, and GEBV for crossbred performance (GEBV-C) based on the MAD. GEBV-C were calculated based on SNP allele frequencies of genotyped animals in the opposite line.ResultsCompared to MA, MAD improved prediction accuracy for both lines. For MAD, GEBV-C improved prediction accuracy compared to GEBV. For Landrace (Yorkshire) boars, prediction accuracies were equal to 0.11 (0.32) for GEBV based on MA, and 0.13 (0.34) and 0.14 (0.36) for GEBV and GEBV-C based on MAD, respectively. Combining animals from both lines into a single reference population yielded higher accuracies than training on each pure line separately. In conclusion, the use of a dominance model increased the accuracy of genomic predictions of crossbred performance based on purebred data.Electronic supplementary materialThe online version of this article (doi:10.1186/s12711-016-0220-2) contains supplementary material, which is available to authorized users.

Genomic prediction of growth in pigs based on a model including additive and dominance effects.

Independent of whether prediction is based on pedigree or genomic information, the focus of animal breeders has been on additive genetic effects or 'breeding values'. However, when predicting phenotypes rather than breeding values of an animal, models that account for both additive and dominance effects might be more accurate. Our aim with this study was to compare the accuracy of predicting phenotypes using a model that accounts for only additive effects (MA) and a model that accounts for both additive and dominance effects simultaneously (MAD). Lifetime daily gain (DG) was evaluated in three pig populations (1424 Pietrain, 2023 Landrace, and 2157 Large White). Animals were genotyped using the Illumina SNP60K Beadchip and assigned to either a training data set to estimate the genetic parameters and SNP effects, or to a validation data set to assess the prediction accuracy. Models MA and MAD applied random regression on SNP genotypes and were implemented in the program Bayz. The additive heritability of DG across the three populations and the two models was very similar at approximately 0.26. The proportion of phenotypic variance explained by dominance effects ranged from 0.04 (Large White) to 0.11 (Pietrain), indicating that importance of dominance might be breed-specific. Prediction accuracies were higher when predicting phenotypes using total genetic values (sum of breeding values and dominance deviations) from the MAD model compared to using breeding values from both MA and MAD models. The highest increase in accuracy (from 0.195 to 0.222) was observed in the Pietrain, and the lowest in Large White (from 0.354 to 0.359). Predicting phenotypes using total genetic values instead of breeding values in purebred data improved prediction accuracy and reduced the bias of genomic predictions. Additional benefit of the method is expected when applied to predict crossbred phenotypes, where dominance levels are expected to be higher.

Listening to disembodied voices: anthropological and psychiatric challenges

What is the role of the voice in Indian explanatory models of madness and psychiatric nosology? Anthropological and psychiatric challenges, it is argued, are crystallised in the voice, a medium that signifies the intersection of models of occult madness and schizophrenia. The psychiatry and religious healing practised at a Sufi shrine in Gujarat differed in terms of the status accorded to the voice: psychiatry interpreted the voice as a symptom of mental disorder, whereas religious healing used the medium in ambiguous practices of possession trance, combining performances of madness and healing. Although ‘doing trance’ is considered an essential part in the process of healing, patients diagnosed with schizophrenia do not experience trance. Their patiency is displaced onto a caretaker. Psychiatric theories resting on the somatised mind partly converge with theories of madness based on sorcery and possession in so far as both posit a direct link between the brain and behaviour. Against the background of the contested religious healing sites that are currently debated in Indian public mental health, attention to multiple dimensions of the voice reveals its significance as an alternative to the psychiatric institutionalisation of people coping with mental disorder. The voice reconciles the dichotomy between scientific psychiatry and traditional ritual healing, partly by making sense of madness by engaging with the sense of hearing.