The Affordable Care Act, Medicare Costs, and Retirement Security

Rising Medicare costs have been a major contributor to projected long-run budget deficits, and rising outof-pocket costs have become an increasing challenge to individuals' retirement security. The 2010 Patient Protection and Affordable Care Act (ACA) made substantial changes to Medicare, designed both to improve the program's finances and to reduce the outof-pocket costs faced by retirees. However, the Office of the Actuary (OACT) at the Centers for Medicare & Medicaid Services (CMS) warns that the assumed impact of the ACA may be overly optimistic and that realized savings may be far more muted. As a result, since 2010, OACT each year has released a set of alternative projections to illustrate Medicare expenditures if current-law payment reductions are not sustained.This brief compares the baseline projections in the annual Medicare Trustees Report with OACT's alternative projections

The EU referendum and the shaming of leave voters

A day right after EU referendum result came out, my Facebook page exploded. Full of words of anger and shock, almost all of my friends were expressing their frustration and disappointment. This is very easy to understand because most of my Facebook friends are university undergraduates. Young and well-educated, they are statistically perfect remain voters. Unlike my remain-oriented sample, the EU referendum told us the fact that almost 52% of the population wanted to leave. It was more than a shock to us, after all, the people in our lives including parents, peers, teachers – and to some extent Londoners – were overwhelmingly supporting remain. What made our prediction wrong? Who is it to blame

On Complexity of Stability Analysis in Higher-order Ecological Networks through Tensor Decompositions

Complex ecological networks are often characterized by intricate interactions that extend beyond pairwise relationships. Understanding the stability of higher-order ecological networks is salient for species coexistence, biodiversity, and community persistence. In this article, we present complexity analyses for determining the linear stability of higher-order ecological networks through tensor decompositions. We are interested in the higher-order generalized Lotka-Volterra model, which captures high-order interactions using tensors of varying orders. To efficiently compute Jacobian matrices and thus determine stability in large ecological networks, we exploit various tensor decompositions, including higher-order singular value decomposition, Canonical Polyadic decomposition, and tensor train decomposition, accompanied by in-depth computational and memory complexity analyses. We demonstrate the effectiveness of our framework with numerical examples.Comment: 6 pages, 3 figure

Investigation of the Interaction Between Antimicrobial Peptides and Lipid Membranes Using Ion Mobility Mass Spectrometry Coupled with Isothermal Titration Calorimetry

Antimicrobial peptides (AMP) are involved in many biological processes owing to their ability to interact with the cell membranes. The aim of many biophysical methods is to understand the mechanism of AMP function such that their bioactivities can be tailored for therapeutic purposes. There is no single experimental technique that can provide a complete understanding of the mechanism of AMP-bilayer interactions; however, this emphasizes the necessity for a combination of techniques in order to provide a more complete view of cellular processes. In this study, ion mobility mass spectrometry (IM-MS) is coupled with isothermal titration calorimetry (ITC) to study the interaction between antimicrobial peptide gramicidin A (GA) with lipid bilayer as well as between antimicrobial peptide gramicidin S (GS) with lipid bilayer. IM-MS can probe the membrane bound structure of GA and the conformer preferences of GA can be influenced by the physical properties of lipid comprising the bilayer. The information obtained from IM-MS is limited to investigation into structural changes of the peptide and the effects of the peptide on surrounding lipids remain to be resolved. Here, ITC is used as a complementary technique to elucidate the lipid-peptide interactions. ITC is capable of providing a thermodynamic description of the entire binding process of GS to various lipid bilayer model membranes. The thermodynamics of the binding of GS can be affected by the properties of the bilayer, thus it is possible to incorporate small molecules that affect the bilayer physiochemical properties, such as cholesterol, or peptide like GA into the bilayer and study how the presence of these molecules affects the thermodynamics of GS binding. Also, since the conformer preferences of GA in membrane is sensitive to the lipid structure and composition, and the conformational changes of GA can be probed by IM-MS, it is also possible to use GA as a “reporter” to investigate how binding of GS changes the lipid environment. The mechanism of GA and GS interaction with lipid bilayer can thus be elucidated through combining the information obtained from ITC with that from IM-MS

Exploring the Standard and Extended Cosmological Models Using High-Precision Large Scale Observations

Modern precision cosmology is undergoing rapid development thanks to the measurements obtained from large scale cosmological surveys. This information both elucidates our knowl- edge about the universe and brings in new challenges. The first challenge is to robustly analyze the growing amount of data that need further compression and post-processes, in order to produce the cosmological interpretation correctly. The second challenge is to pro- pose and constrain extended cosmological models that can potentially resolve the tensions appearing in the high-precision measurements. In this thesis, I first summarize modern cos- mology theory predictions on background and perturbation level in chapter 13. Chapter 4-6 are about my research in the Dark Energy Survey on different topics. In Chapter 4, I present my investigation on the theory systematic uncertainty caused by baryonic feedbacks in the cosmic shear analysis, for the Dark Energy Survey Year-3 precision. The conclusion is that introducing two extra halo parameters to describe the baryonic effect can protect us from biasing the cosmological parameter constraints, but the gain on the constraint power from the small scale is too small to worth doing so. Next, in chapter 5, I discuss several techni- cal details in terms of the statistics being done to verdict the conclusions on the extended cosmological parameters and models in DES Year-1 extensions paper. The conclusion is that the kernel used for kernel density estimation should always be linearly corrected for the Monte Carlo chains in a blinded cosmological analysis. In Chapter 6 I constrain on a phenomenological model where dark matter converts to dark radiation at low redshifts, using the Dark Energy Survey Year-1 data combined with external data. The conclusion is that when combining all data sets less than 3.7% in fraction of the current amount of dark matter could have been converted away. Furthermore, the extended model does not help much on H0 or S8 tensions between early and late universe measurements, and it does not fit the data better (or worse) than the ΛCDM model at current precision. Finally, in chapter 7, I further the discussion on the problem of certain ΛCDM assumptions used in the combined-probe analysis for extended cosmological models.PHDPhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169700/1/anqich_1.pd

What Are the Implications of Rising Debt for Older Americans?

The share of older Americans with debt has been on the rise over the last several decades. Having debt, however, does not always signal financial fragility because debt can be used for various purposes. For example, households that take out a low-interest mortgage to buy a home, which typically appreciates in value, are likely making a savvy choice. In contrast, households that carry unpaid credit card balances could see their debt snowball, leading to financial distress. Identifying these distinctions in household debt situations is crucial to understanding the implications of the rise in debt holding among seniors.  This brief, based on a new paper, addresses three key questions: 1) As more older households carry debt in retirement, what share are at "high-risk" and "low-risk" of financial hardship? 2) Is the growth in debt holding driven by the high- or low-risk households? and 3) What are the different types of high-risk households?The answers will help policymakers determine which types of borrowers are most vulnerable and develop tailored solutions for assisting them.   The discussion proceeds as follows. The first section provides background on trends in debt holding among older Americans. The second section sorts households into high-risk and low-risk based on their debt and asset profiles, and it shows that high-risk borrowers are driving the growth in debt. The third section identifies four groups of high-risk borrowers with very different characteristics. Given the diverse situations of high-risk borrowers, the fourth section suggests some potential ways to address each group's specific needs. The final section concludes that the debt burdens of high-risk borrowers are cause for concern, but a one-size-fits-all solution does not exist, so targeted interventions would be most effective.  Click "Download" to access this resource