6,618 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 “melting pot” 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 “welfare reform” 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
Accuracy of Measuring Intensity Through Means of Repetition in Reserve in Trained College Females
poste
Pinning and switching of magnetic moments in bilayer graphene
We examine the magnetic properties of the localized states induced by lattice
vacancies in bilayer graphene with an unrestricted Hartree-Fock calculation. We
show that with realistic values of the parameters and for experimentally
accessible gate voltages we can have a magnetic switching between an
unpolarized and a fully polarized system.Comment: 9 pages, 4 figure
Snowmelt Timing Regulates Community Composition, Phenology, and Physiological Performance of Alpine Plants
The spatial patterning of alpine plant communities is strongly influenced by the variation in physical factors such as temperature and moisture, which are strongly affected by snow depth and snowmelt patterns. Earlier snowmelt timing and greater soil-moisture limitations may favor wide-ranging species adapted to a broader set of ecohydrological conditions than alpine-restricted species. We asked how plant community composition, phenology, plant water relations, and photosynthetic gas exchange of alpine-restricted and wide-ranging species differ in their responses to a ca. 40-day snowmelt gradient in the Colorado Rocky Mountains (Lewisia pygmaea, Sibbaldia procumbens, and Hymenoxys grandiflora were alpine-restricted and Artemisia scopulorum, Carex rupestris, and Geum rossii were wide-ranging species). As hypothesized, species richness and foliar cover increased with earlier snowmelt, due to a greater abundance of wide-ranging species present in earlier melting plots. Flowering initiation occurred earlier with earlier snowmelt for 12 out of 19 species analyzed, while flowering duration was shortened with later snowmelt for six species (all but one were wide-ranging species). We observed >50% declines in net photosynthesis from July to September as soil moisture and plant water potentials declined. Early-season stomatal conductance was higher in wide-ranging species, indicating a more competitive strategy for water acquisition when soil moisture is high. Even so, there were no associated differences in photosynthesis or transpiration, suggesting no strong differences between these groups in physiology. Our findings reveal that plant species with different ranges (alpine-restricted vs. wide-ranging) could have differential phenological and physiological responses to snowmelt timing and associated soil moisture dry-down, and that alpine-restricted species’ performance is more sensitive to snowmelt. As a result, alpine-restricted species may serve as better indicator species than their wide-ranging heterospecifics. Overall, alpine community composition and peak % cover are strongly structured by spatio-temporal patterns in snowmelt timing. Thus, near-term, community-wide changes (or variation) in phenology and physiology in response to shifts in snowmelt timing or rates of soil dry down are likely to be contingent on the legacy of past climate on community structure
Asthma prescribing, ethnicity and risk of hospital admission: an analysis of 35,864 linked primary and secondary care records in East London
This work was partly supported by funding from the Asthma UK Centre for Applied Research
Nonlinear Localization in Metamaterials
Metamaterials, i.e., artificially structured ("synthetic") media comprising
weakly coupled discrete elements, exhibit extraordinary properties and they
hold a great promise for novel applications including super-resolution imaging,
cloaking, hyperlensing, and optical transformation. Nonlinearity adds a new
degree of freedom for metamaterial design that allows for tuneability and
multistability, properties that may offer altogether new functionalities and
electromagnetic characteristics. The combination of discreteness and
nonlinearity may lead to intrinsic localization of the type of discrete
breather in metallic, SQUID-based, and symmetric metamaterials. We
review recent results demonstrating the generic appearance of breather
excitations in these systems resulting from power-balance between intrinsic
losses and input power, either by proper initialization or by purely dynamical
procedures. Breather properties peculiar to each particular system are
identified and discussed. Recent progress in the fabrication of low-loss,
active and superconducting metamaterials, makes the experimental observation of
breathers in principle possible with the proposed dynamical procedures.Comment: 19 pages, 14 figures, Invited (Review) Chapte
Validation of Tissue Modelization and Classification Techniques in T1-Weighted MR Brain Images
We propose a deep study on tissue modelization and classification Techniques on T1-weighted MR images. Three approaches have been taken into account to perform this validation study. Two of them are based on Finite Gaussian Mixture (FGM) model. The first one consists only in pure gaussian distributions (FGM-EM). The second one uses a different model for partial volume (PV) (FGM-GA). The third one is based on a Hidden Markov Random Field (HMRF) model. All methods have been tested on a Digital Brain Phantom image considered as the ground truth. Noise and intensity non-uniformities have been added to simulate real image conditions. Also the effect of an anisotropic filter is considered. Results demonstrate that methods relying in both intensity and spatial information are in general more robust to noise and inhomogeneities. However, in some cases there is no significant differences between all presented methods
A brief history of learning classifier systems: from CS-1 to XCS and its variants
© 2015, Springer-Verlag Berlin Heidelberg. The direction set by Wilson’s XCS is that modern Learning Classifier Systems can be characterized by their use of rule accuracy as the utility metric for the search algorithm(s) discovering useful rules. Such searching typically takes place within the restricted space of co-active rules for efficiency. This paper gives an overview of the evolution of Learning Classifier Systems up to XCS, and then of some of the subsequent developments of Wilson’s algorithm to different types of learning
Development of Proficiency Testing for Detection of Irradiated Food: Project E01068. Results of Second Round PSL and TL Trials, September 2006
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