Empiricism in artificial life

Strong artificial life research is often thought to rely on Alife systems as sources of novel empirical data. It is hoped that by augmenting our observations of natural life, this novel data can help settle empirical questions, and thereby separate fundamental properties of living systems from those aspects that are merely contingent on the idiosyncrasies of terrestrial evolution. Some authors have questioned whether this approach can be pursued soundly in the absence of a prior, agreed-upon definition of life. Here we compare Alife’s position to that of more orthodox empirical tools that nevertheless suffer from strong theory-dependence. Drawing on these examples, we consider what kind of justification might be needed to underwrite artificial life as empirical enquiry. In the title of the first international artificial life conference

Deforestation, degradation, and natural disturbance in the Amazon: using a new monitoring approach to estimate area and carbon loss

Forest degradation causes environmental damage and carbon emissions, but its extent and magnitude are not well understood. New methods for monitoring forest degradation and deforestation show that more disturbance has occurred in the Amazon in recent decades than previously realized, indicating an unaccounted for source of carbon emissions and damage to Amazon ecosystems. Forest degradation and natural disturbance change a landscape, but the visible damage apparent in satellite images may be temporary and difficult to differentiate from undisturbed forests. Time series analysis of Landsat data used in a spectral mixture analysis improves monitoring of forest degradation and natural disturbance. In addition, the use of statistical inference accounts for classification bias and provides an estimate of uncertainty. Application of the methodology developed in this dissertation to the Amazon Ecoregion found that forest degradation and natural disturbance were more prevalent than deforestation from 1995 to 2017. Of consequence, the total area of forest in the Amazon that has been recently disturbed is greater than previously known. Overall, deforestation affected 327,900 km2 (±15,500) of previously undisturbed forest in the Amazon while degradation and natural disturbance affected 434,500 km2 (±22,100). Forest degradation and natural disturbance occur more frequently during drought years, which have increased in frequency and severity in recent years. Deforestation has largely decreased since 2004, while forest degradation and natural disturbance have remained consistent. Previously disturbed forests are lower in biomass than undisturbed forests, yet regeneration after disturbance gradually sequesters carbon. A carbon flux model shows that gross aboveground carbon loss from forest degradation and natural disturbance and deforestation from 1996 to 2017 in the Amazon were 2.2-2.8 Pg C and 3.3-4.3 Pg C, respectively. Since 2008, however, carbon loss from degradation and natural disturbance has been approximately the same as from deforestation. The methodologies developed in this dissertation are useful for monitoring deforestation and degradation throughout the world’s forest ecosystems. By leveraging dense data time series, statistical inference, and carbon modeling it is possible to quantify areas of deforestation and forest degradation in addition to the resulting carbon emissions. The results of this dissertation stress the importance of degradation and natural disturbance in the global carbon cycle and information valuable for climate science and conservation initiatives

Adaptation of Dopamine Neurons' Mismatch Sensitivity Is not Compatible With Reinforcement Learning Theory

Recent electrophysical data inspired the claim that dopaminergic neurons adapt their mismatch sensitivities to reflect variances of expected rewards. This contradicts reward prediction error theory and most basal ganglia models. Application of learning principles points to a testable alternative interpretation-of the same data-that is compatible with existing theory.National Science Foundation (SBE-354378); Higher Education Council of Turkey; Canakkale Onsekiz Mart University of Turke

Linked lives: the utility of an agent-based approach to modelling partnership and household formation in the context of social care

The UK’s population is aging, which presents a challenge as older people are the primary users of health and social care services. We present an agent-based model of the basic demographic processes that impinge on the supply of, and demand for, social care: namely mortality, fertility, health-status transitions, internal migration, and the formation and dissolution of partnerships and households. Agent-based modeling is used to capture the idea of “linked lives” and thus to represent hypotheses that are impossible to express in alternative formalisms. Simulation runs suggest that the per-taxpayer cost of state-funded social care could double over the next forty years. A key benefit of the approach is that we can treat the average cost of state-funded care as an outcome variable, and examine the projected effect of different sets of assumptions about the relevant social processes

Polarization Angle Calibration And B-Mode Characterization With The Bicep And Keck Array CMB Telescopes

University of Minnesota Ph.D. dissertation.March 2018. Major: Astrophysics. Advisor: Clement Pryke. 1 computer file (PDF); xiii, 169 pages.Since its discovery in 1964, the Cosmic Microwave Background (CMB) has led to widespread acceptance of the Big Bang cosmological paradigm as an explanation for the evolution of the Universe. However, this paradigm does not explain the origin of the initial conditions, leading to such issues as the “horizon problem” and “flatness problem.” In the early 1980’s, the inflationary paradigm was introduced as a possible source for the initial conditions. This theory postulates that the Universe underwent a period of exponential expansion within a tiny fraction of a second after the beginning. Such an expansion is predicted to inject a stochastic background of gravitational waves that could imprint a detectable B-mode (curl-like) signal in the polarization of the CMB. It is this signal that the family of telescopes used by the BICEP1, BICEP2, and Keck Array collaborations were designed to detect. These telescopes are small aperture, on-axis, refracting telescopes. We have used the data from these telescopes, particularly BICEP2 and the Keck Array, to place the tightest constraints, as of March 2016, on the tensor-to-scalar ratio of the CMB of r_{0.05} < 0.07. In this dissertation, we provide an overview of the Keck Array telescopes and analysis of the data. We also investigate, as the main focus of this dissertation, a device we call the Dielectric Sheet Calibrator (DSC) that is used to measure the polarization angles of our detectors as projected on the sky. With these measurements, we gain the potential to separate the polarization rotation effects of parity-violating physics, such as cosmic birefringence, from a systematic uncertainty on our detectors’ polarization angles. Current calibration techniques for polarization sensitive CMB detectors claim an accuracy of ±0.5°, which sets a limit for determining the usefulness of the DSC. Through a series of consistency tests on a single Keck Array receiver, we demonstrate a statistical uncertainty on the DSC measurements of ±0.03° and estimate a systematic uncertainty of ±0.2°. which meets the minimum goal. We also conclude that there is no conflict between the DSC-derived polarization angles of this single receiver and the rotation derived from that receiver’s CMB data under the hypothesis of no cosmic birefringence

State and local agencies are more effective than the federal government in housing discrimination enforcement

Discrimination by those selling or renting homes is illegal under the 1968 Fair Housing Act (known as Title VIII), but housing discrimination and segregation in the US have not been eliminated. Federal, state, and local agencies are responsible for enforcing Title VIII, so in which part of government is enforcement most effective? In new research which analyses data from the ..

Race, Ethnicity, and Fair Housing Enforcement: A Regional Analysis

This article systematically compares how federal, state, and local civil rights agencies in the ten standard regions of the United States enforce fair housing law complaints filed by Blacks and Latinos. Specifically, it explores the extent to which regional outcomes at all three levels of government are decided favorably where, between 1989 and 2010, a racial or ethnic violation of the Fair Housing Act of 1968 or the Fair Housing Amendments Act of 1988 is alleged. The results reveal significant variations in outcomes between these groups across the country. Most importantly, the probability of an outcome favorable to the complainant depends on the region in which the complaint is filed, the race or ethnicity of the complainant, and the racial or ethnic composition and the number of complaints filed per capita in the state in which a complaint originates. In general, while complaints filed by Latinos are more likely to receive a favorable outcome than those filed by Blacks, favorability rates for Latinos are more dependent on the region where the complaint is processed than they are for Blacks

Attitudes Toward Anger Management Scale: Development and Initial Validation

This article describes the development and preliminary validation of the Attitudes Toward Anger Management Scale (ATAMS), a self-report measure of attitudes toward anger management services. Undergraduate volunteers (N = 415) completed an initial version of the instrument. Principal components analysis yielded a two-factor solution. Convergent and incremental validities were supported

Effects of Alcohol on Tests of Executive Functioning in Men and Women: A Dose Response Examination

Alcohol has been shown to affect performance on tasks associated with executive functioning. However, studies in this area have generally been limited to a single dose or gender or have used small sample sizes. The purpose of this study was to provide a more nuanced and systematic examination of alcohol\u27s effects on commonly used tests of executive functioning at multiple dosages in both men and women. Research volunteers (91 women and 94 men) were randomly assigned to one of four drink conditions (alcohol doses associated with target blood alcohol concentrations of .000%, .050%, .075%, and .100%). Participants then completed three tasks comprising two domains of executive functioning: two set shifting tasks, the Trail Making Test and a computerized version of the Wisconsin Card Sorting Task, and a response inhibition task, the Go Stop Impulsivity Paradigm. Impaired performance on set shifting tasks was found at the .100% and .075% dosages, but alcohol intoxication did not impair performance on the Go Stop. No gender effects emerged. Thus, alcohol negatively affects set shifting at moderately high levels of intoxication in both men and women, likely attributable to alcohol\u27s interference with prefrontal cortex function. Although it is well established that alcohol negatively affects response inhibition as measured by auditory stop-signal tasks, alcohol does not appear to exert a negative effect on response inhibition as measured by the Go Stop, a visual stop-signal task