6,780 research outputs found
Systemic Racism and COVID-19: Vulnerabilities with the U.S. Social Safety Net for Immigrants and People of Color
America has a mythologized reputation as an accommodative âmelting potâ nation that welcomes individuals from all races and countries seeking improved quality of life and reduced material hardship. However, our U.S. social welfare system is more broadly characterized as underdeveloped, restrictive, and exclusionary, especially toward immigrants and people of color. Public health benefits (e.g., Medicaid), food assistance programs (e.g., SNAP), rental assistance (e.g., HCV/Section 8), and cash assistance (e.g., TANF) are oftentimes restricted for immigrants and racial minorities, making them more vulnerable to material hardship and more exposed to pandemic conditions under COVID-19. Moreover, these welfare restrictions are oftentimes rooted in negative social construction and unflattering stereotypes of Black and Latine people. This paper connects deliberately racialized social welfare barriers, developed under the banner of âwelfare reformâ in the 1990s, to contemporary difficulties accessing benefits by minority groups, and subsequently heightened vulnerabilities around COVID-19. We suggest areas for improvement in social welfare policy development to better address systemic racism and COVID-19, and deepening inequalities from lack of access to the social safety net for immigrants and racial minorities in the U.
The role of hydrogen in room-temperature ferromagnetism at graphite surfaces
We present a x-ray dichroism study of graphite surfaces that addresses the
origin and magnitude of ferromagnetism in metal-free carbon. We find that, in
addition to carbon states, also hydrogen-mediated electronic states
exhibit a net spin polarization with significant magnetic remanence at room
temperature. The observed magnetism is restricted to the top 10 nm of
the irradiated sample where the actual magnetization reaches emu/g
at room temperature. We prove that the ferromagnetism found in metal-free
untreated graphite is intrinsic and has a similar origin as the one found in
proton bombarded graphite.Comment: 10 pages, 5 figures, 1 table, submitted to New Journal of Physic
Optimality-based Analysis of XCSF Compaction in Discrete Reinforcement Learning
Learning classifier systems (LCSs) are population-based predictive systems
that were originally envisioned as agents to act in reinforcement learning (RL)
environments. These systems can suffer from population bloat and so are
amenable to compaction techniques that try to strike a balance between
population size and performance. A well-studied LCS architecture is XCSF, which
in the RL setting acts as a Q-function approximator. We apply XCSF to a
deterministic and stochastic variant of the FrozenLake8x8 environment from
OpenAI Gym, with its performance compared in terms of function approximation
error and policy accuracy to the optimal Q-functions and policies produced by
solving the environments via dynamic programming. We then introduce a novel
compaction algorithm (Greedy Niche Mass Compaction - GNMC) and study its
operation on XCSF's trained populations. Results show that given a suitable
parametrisation, GNMC preserves or even slightly improves function
approximation error while yielding a significant reduction in population size.
Reasonable preservation of policy accuracy also occurs, and we link this metric
to the commonly used steps-to-goal metric in maze-like environments,
illustrating how the metrics are complementary rather than competitive
Interethnic Interactions: Expectancies, Emotions, and Behavioral Intentions
Two studies examine Hispanic and non-Hispanic White people's responses to interethnic interactions. Consistent with previous findings regarding White/Black interactions, participants who had negative expectations about intergroup interactions reported more anger and anxiety about interethnic interactions. These negative emotional responses, in turn, were associated with negative behavioral intentions such as the desire to avoid interethnic interactions and the externalization of blame if an interethnic interaction did not go well. Across the studies, White participants who were angry about interethnic interactions wanted to avoid these interactions, whereas anxiety was the key predictor of avoidance for the Hispanic participants. Results are discussed in terms of their implications for developing models of intergroup interactions and designing approaches to improve these interactions
Homotransplantation of multiple visceral organs
It was technically possible to perform simultaneous homotransplantation of multiple visceral organs including the liver, spleen, pancreas, omentum and the entire gastrointestinal tract. Arterialization of the cooled graft was accomplished through the donor aorta which was removed with the graft and attached to that of the recipient dog. Gastrointestinal hemorrhage after surgery accounted for a high operative mortality and was thought to be due to denervation of the graft. The five dogs which survived the immediate trauma of surgery lived for five and a half to nine days. After the second day, these animals were physically active and able to resume oral alimentation. In three dogs, there was metabolic evidence of rejection of the liver. In two others, jaundice did not develop. These observations were compared with chemical, hematologic and pathologic data obtained in previous experiments involving homotransplantation of the liver alone. In some cases, there was less evidence of host versus graft rejection after the multiple organ transplants. Other data in the present study suggested the possibility that a significant graft versus host reaction may have been an important contributory cause of death. © 1962
ErtragsstabilitĂ€t und QualitĂ€t von Weizensortenmischungen im Ăkologischen Anbau
Disease development, yield and baking quality were assessed on the winter wheat cultivars Arina and Capo and their 1:1 mixture in a total of 12 sites on-farm in 2002/2003. Due to a severe drought disease severities were very low and probably had little effect on the plants. The more drought tolerant variety Capo over-yielded in mixtures on average by 21% while Arina yielded in mixtures as expected. Protein and gluten contents and baking volume in pure stands of Arina were usually higher than for Capo. Both varieties changed their quality parameters in mixtures. However, the parameters of the mixtures were not equal to the mean of the pure stands indicating some unknown interactions. The quality parameters of each variety or mixture were compared to the mean of all treatments in a given site allowing for regression analysis across sites. Capo was least able to improve its quality in reaction to improved site potential (expressed as mean baking volume) (slope: 0.64) while the mixtures reacted strongest (slope: 1.47). This indicates that mixtures might be better able to profit from good growing conditions than pure stands
Kripke Semantics for Martin-L\"of's Extensional Type Theory
It is well-known that simple type theory is complete with respect to
non-standard set-valued models. Completeness for standard models only holds
with respect to certain extended classes of models, e.g., the class of
cartesian closed categories. Similarly, dependent type theory is complete for
locally cartesian closed categories. However, it is usually difficult to
establish the coherence of interpretations of dependent type theory, i.e., to
show that the interpretations of equal expressions are indeed equal. Several
classes of models have been used to remedy this problem. We contribute to this
investigation by giving a semantics that is standard, coherent, and
sufficiently general for completeness while remaining relatively easy to
compute with. Our models interpret types of Martin-L\"of's extensional
dependent type theory as sets indexed over posets or, equivalently, as
fibrations over posets. This semantics can be seen as a generalization to
dependent type theory of the interpretation of intuitionistic first-order logic
in Kripke models. This yields a simple coherent model theory, with respect to
which simple and dependent type theory are sound and complete
The ASPECTA toolkit : affordable Full Coverage Displays
Full Coverage Displays (FCDs) cover the interior surface of an entire room with pixels. FCDs make possible many new kinds of immersive display experiences - but current technology for building FCDs is expensive and complex, and software support for developing full-coverage applications is limited. To address these problems, we introduce ASPECTA, a hardware configuration and software toolkit that provide a low-cost and easy-to-use solution for creating full coverage systems. We outline ASPECTAâs (minimal) hardware requirements and describe the toolkitâs architecture, development API, server implementation, and configuration tool; we also provide a full example of how the toolkit can be used. We performed two evaluations of the toolkit: a case study of a research system built with ASPECTA, and a laboratory study that tested the effectiveness of the API. Our evaluations, as well as multiple examples of ASPECTA in use, show how ASPECTA can simplify configuration and development while still dramatically reducing the cost for creators of applications that take advantage of full-coverage displays.Postprin
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