How Will Declining Rates of Marriage Reshape Eligibility for Social Security?

For most older people in the United States, Social Security is the major source of income: nine out of ten people age 65 or older receive benefits, which represent an average of 41 percent of their income. Largely as a result of Social Security, poverty rates for the elderly are at an all-time low, just 10 percent. But pockets of poverty persist: older unmarried persons, blacks, and Hispanics experience poverty rates in excess of 20 percent, and over 40 percent of all older single black women live in poverty. People quality for Social Security based either on their work record or their marital status. Most older women receive noncontributory Social Security spouse of widow benefits on the basis of their marital history. For these women, marital status is more important than employment status in shaping old-age financial security. However, the trend to marry and stay married has declined over time in the United States, particularly among black women. This, we hypothesize, means that fewer women will qualify for spouse and widow benefits in coming decades. As a result, Social Security benefits will shrink among the very population that currently reports higher poverty rates, older single women, particularly black women. In this policy brief, we ask: Compared to earlier cohorts, what proportion of white, black, and Hispanic women born in the 1940s, 1950s, and 1960s will enter old age without a marriage that qualifies them for Social Security spouse and widow benefits? We find that the proportion who will reach age 62 without a qualifying marriage, and thus be ineligible for Social Security spouse and widow benefits, is increasing modestly for whites and Hispanics but dramatically for African Americans. Most of these women will be eligible for retired worker benefits under Social Security, but those benefits are not likely to be as large as the benefits they would have received as spouses and widows, had they been eligible. We then discuss a range of policy alternatives, including the possibility of a minimum benefit.Social Security, spousal benefits, widow benefits, poverty, elderly, social welfare, income security.

Numerical algebraic geometry for model selection and its application to the life sciences

Researchers working with mathematical models are often confronted by the related problems of parameter estimation, model validation, and model selection. These are all optimization problems, well-known to be challenging due to non-linearity, non-convexity and multiple local optima. Furthermore, the challenges are compounded when only partial data is available. Here, we consider polynomial models (e.g., mass-action chemical reaction networks at steady state) and describe a framework for their analysis based on optimization using numerical algebraic geometry. Specifically, we use probability-one polynomial homotopy continuation methods to compute all critical points of the objective function, then filter to recover the global optima. Our approach exploits the geometric structures relating models and data, and we demonstrate its utility on examples from cell signaling, synthetic biology, and epidemiology.Comment: References added, additional clarification

Monitoring wolf populations using howling points combined with sign survey transects

Wolves respond to simulated howling, especially during the mating and breeding seasons. Simulated howling points are, therefore, commonly used by many wolf researchers around the world to estimate pack numbers in a given area. A large amount of information is available on various pack breeding areas in Asturias, the only region in north-western Spain where the Iberian wolf (Canis lupus signatus, Cabrera 1907) is not classed as a game species. Wolf research began there in the early 1980s. We present the results of the latest study on population status, conducted between July and November, 2001. Using sampling transects to detect wolf scat and scratch marks and designated howling and observation points, twenty one (21) wolf packs were definitely located, with two others considered “likely”. Nineteen (19) packs were detected using howling points (n=314). The results of this study show that simulated howling points and sampling transects are reliable and inexpensive way of detecting wolf packs

Intrinsic dissipation in high-frequency micromechanical resonators

We report measurements of intrinsic dissipation in micron-sized suspended resonators machined from single crystals of galium arsenide and silicon. In these experiments on high-frequency micromechanical resonators, designed to understand intrinsic mechanisms of dissipation, we explore dependence of dissipation on temperature, magnetic field, frequency, and size. In contrast to most of the previous measurements of acoustic attenuation in crystalline and amorphous structures in this frequency range, ours is a resonant measurement; dissipation is measured at the natural frequencies of structural resonance, or modes of the structure associated with flexural and torsional motion. In all our samples we find a weakly temperature dependent dissipation at low temperatures. We compare and contrast our data to various probable mechanisms, including thermoelasticity, clamping, anharmonic mode-coupling, surface anisotropy and defect motion, both in bulk and on surface. The observed parametric dependencies indicate that the internal defect motion is the dominant mechanism of intrinsic dissipation in our samples

Dynamics of Surface Roughening with Quenched Disorder

We study the dynamical exponent $z$ for the directed percolation depinning (DPD) class of models for surface roughening in the presence of quenched disorder. We argue that $z$ for $(d+1)$ dimensions is equal to the exponent $d_{\rm min}$ characterizing the shortest path between two sites in an isotropic percolation cluster in $d$ dimensions. To test the argument, we perform simulations and calculate $z$ for DPD, and $d_{\rm min}$ for percolation, from $d = 1$ to $d = 6$.Comment: RevTex manuscript 3 pages + 6 figures (obtained upon request via email [email protected]

Perceived racism as a predictor of depression and cultural mistrust

We examined the role of perceived racism as a predictor of depression and cultural mistrust in African American, Hispanic American, Asian American, and Caucasian students. Design: 65 university students of varying racial and ethnic backgrounds completed the Perceived Racism Scale, Beck Depression Inventory second edition, and Cultural Mistrust Inventory-Revised. Results: African Americans experienced the highest levels of perceived racism, followed by Hispanic Americans, Asian Americans, and Caucasians. Higher levels of perceived racism were associated with increased cultural mistrust, while depression and mistrust varied with ethnic background. Further, high perceived racism was associated with increased cultural mistrust for African American and Caucasian participants, and decreased mistrust for Hispanic American and Asian American participants. Finally, minority males reported higher depression and mistrust than minority females, while Caucasian females reported higher depression and mistrust than Caucasian mules. Conclusion: Perceptions of racism differed by ethnic group, and interacted with ethnicity and gender to predict reported depression and cultural mistrust

Notch signaling regulates perivascular adipose tissue (PVAT) function during diet-induced obesity

Objectives: -To test the hypothesis that canonical Notch signaling influence vascular function by regulating PVAT-derived vascular relaxation factors. -To determine how overexpression of Notch signaling or loss of the key Notch signaling component influence PVAT function.https://knowledgeconnection.mainehealth.org/lambrew-retreat-2021/1035/thumbnail.jp

Scattering of Dirac particles from non-local separable potentials: the eigenchannel approach

An application of the new formulation of the eigenchannel method [R. Szmytkowski, Ann. Phys. (N.Y.) {\bf 311}, 503 (2004)] to quantum scattering of Dirac particles from non-local separable potentials is presented. Eigenchannel vectors, related directly to eigenchannels, are defined as eigenvectors of a certain weighted eigenvalue problem. Moreover, negative cotangents of eigenphase-shifts are introduced as eigenvalues of that spectral problem. Eigenchannel spinor as well as bispinor harmonics are expressed throughout the eigenchannel vectors. Finally, the expressions for the bispinor as well as matrix scattering amplitudes and total cross section are derived in terms of eigenchannels and eigenphase-shifts. An illustrative example is also provided.Comment: Revtex, 9 pages, 4 figures, published versio