A New Look at the Wealth Adequacy of Older U.S. Households

We examine the current wealth adequacy of older U.S. households using the 1998-2006 waves of the Health and Retirement Study (HRS). We find that the median older U.S. household is reasonably well situated, with a ratio of comprehensive net wealth to present value poverty- line wealth of about 3.9 in 2006. About 18 percent of households, however, have less wealth than would be needed to generate 150 percent of poverty-line income over their expected future lifetimes. We see similar patterns of wealth adequacy when we examine ratios of annualized comprehensive wealth to pre-retirement earnings. Comparing the leading edge of the baby boomers in 2006 to households of the same age in 1998, we find that the baby boomers show slightly less wealth, in real terms, than their elders did, but still have appear to have adequate resources at the median. Moreover, we find a rising age profile of annualized wealth, even within households over time and after controlling for other factors, suggesting that older households are not spending their wealth as quickly as their survival probabilities are falling.

Evaluation and Improvement of Methods to Recover and Detect Hepatitis A Virus and an Indicator Virus (F+ RNA Coliphage MS2) in Representative Foods Associated witrh Viral Foodborne Outbreaks

Seventy-six million illnesses and 5,200 deaths are estimated to occur each year in the United States associated with foodborne transmission of microbial pathogens. Viral pathogens cause an estimated 7 out of 10 foodborne illnesses of known etiology. Improved methods to recover and detect viruses in foods may reduce morbidity and mortality associated with foodborne disease by identifying routes of viral transmission and by improving source tracking for foodborne outbreaks. Methods were developed and evaluated for recovery and detection of an enteric human virus. Hepatitis A virus (HAV), and an indicator virus, F+ RNA coliphage MS2(MS2), in foods commonly associated with viral foodborne outbreaks. In this study, HAV was inoculated into tomato sauce, strawberries, and oysters, then recovered by either an acid-adsorption-elution-concentration (AA/E) method or an alkaline-elution-concentration method. Viruses were detected and enumerated by cell infectivity or by molecular methods. For molecular detection and quantification, viral RNA was extracted and amplified by conventional, nested, or realtime RT-PCR. The results of this study indicate that the AA/E method, initially used to recover low levels of enteric viruses from shellfish, may also be applied for the recovery of viruses from other complex foods, such as produce and sauces. Additionally, produce and sauces contain fewer enzymatic inhibitors to molecular detection than oysters. Because of this, larger produce and sauce samples can be analyzed by molecular detection methods, leading to possibly lower virus detection levels and greater assay sensitivity in these foods.Master of Science in Public Healt

Kinematic dynamo action in a sphere. I. Effects of differential rotation and meridional circulation on solutions with axial dipole symmetry

A sphere containing electrically conducting fluid can generate a magnetic field by dynamo action, provided the flow is sufficiently complicated and vigorous. The dynamo mechanism is thought to sustain magnetic fields in planets and stars. The kinematic dynamo problem tests steady flows for magnetic instability, but rather few dynamos have been found so far because of severe numerical difficulties. Dynamo action might, therefore, be quite unusual, at least for large-scale steady flows. We address this question by testing a two-parameter class of flows for dynamo generation of magnetic fields containing an axial dipole. The class of flows includes two completely different types of known dynamos, one dominated by differential rotation (D) and one with none. We find that 36% of the flows in seven distinct zones in parameter space act as dynamos, while the remaining 64% either fail to generate this type of magnetic field or generate fields that are too small in scale to be resolved by our numerical method. The two previously known dynamo types lie in the same zone, and it is therefore possible to change the flow continuously from one to the other without losing dynamo action. Differential rotation is found to promote large-scale axisymmetric toroidal magnetic fields, while meridional circulation (M) promotes large-scale axisymmetric poloidal fields concentrated at high latitudes near the axis. Magnetic fields resembling that of the Earth are generated by D > 0, corresponding to westward flow at the surface, and M of either sign but not zero. Very few oscillatory solutions are found

Conscientiousness predicts greater recovery from negative emotion

Greater levels of conscientiousness have been associated with lower levels of negative affect. We focus on one mechanism through which conscientiousness may decrease negative affect: effective emotion regulation, as reflected by greater recovery from negative stimuli. In 273 adults who were 35 - 85 years old, we collected self-report measures of personality including conscientiousness and its self-control facet, followed on average 2 years later by psychophysiological measures of emotional reactivity and recovery. Among middle-aged adults (35 - 65 years old), the measures of conscientiousness and self-control predicted greater recovery from, but not reactivity to, negative emotional stimuli. The effect of conscientiousness and self-control on recovery was not driven by other personality variables or by greater task adherence on the part of high conscientiousness individuals. In addition, the effect was specific to negative emotional stimuli and did not hold for neutral or positive emotional stimuli

SNPServer: a real-time SNP discovery tool

SNPServer is a real-time flexible tool for the discovery of SNPs (single nucleotide polymorphisms) within DNA sequence data. The program uses BLAST, to identify related sequences, and CAP3, to cluster and align these sequences. The alignments are parsed to the SNP discovery software autoSNP, a program that detects SNPs and insertion/deletion polymorphisms (indels). Alternatively, lists of related sequences or pre-assembled sequences may be entered for SNP discovery. SNPServer and autoSNP use redundancy to differentiate between candidate SNPs and sequence errors. For each candidate SNP, two measures of confidence are calculated, the redundancy of the polymorphism at a SNP locus and the co-segregation of the candidate SNP with other SNPs in the alignment. SNPServer is available at

SSRPrimer and SSR Taxonomy Tree: Biome SSR discovery

Simple sequence repeat (SSR) molecular genetic markers have become important tools for a broad range of applications such as genome mapping and genetic diversity studies. SSRs are readily identified within DNA sequence data and PCR primers can be designed for their amplification. These PCR primers frequently cross amplify within related species. We report a web-based tool, SSR Primer, that integrates SPUTNIK, an SSR repeat finder, with Primer3, a primer design program, within one pipeline. On submission of multiple FASTA formatted sequences, the script screens each sequence for SSRs using SPUTNIK. Results are then parsed to Primer3 for locus specific primer design. We have applied this tool for the discovery of SSRs within the complete GenBank database, and have designed PCR amplification primers for over 13 million SSRs. The SSR Taxonomy Tree server provides web-based searching and browsing of species and taxa for the visualisation and download of these SSR amplification primers. These tools are available at

Commentary: comparing efficiency in aquatic and terrestrial animal production systems

First paragraph: Aquaculture is receiving increased attention from a variety of stakeholders. This is largely due to its current role in the global food system of supplying more than half of the seafood consumed, and also because the industry continues to steadily expand (UN Food and Agriculture Organization 2018). A recent article in Environmental Research Letters, 'Feed conversion efficiency in aquaculture: do we measure it correctly?', by Fry et al (2018a) found that measuring feed conversion efficiency of selected aquatic and terrestrial farmed animals using protein and calorie retention resulted in species comparisons (least to most efficient) and overlap among species dissimilar from comparisons based on widely used weight-based feed conversion ratio (FCR) values. The study prompted spirited discussions among researchers, industry representatives, and others. A group assembled to write a standard rebuttal, but during this process, decided it was best to engage the study's original authors to join the discourse. Through this collaboration, we provide the resultant additional context relevant to the study in order to advance conversations and research on the use of efficiency measures in aquatic and terrestrial animal production systems

Intersecting D5-brane models with massive vector-like leptons

We construct eight-stack intersecting D5-brane models, with an orbifold transverse space, that yield the (non-supersymmetric) standard model up to vector-like leptons. The matter includes right-chiral neutrinos and the models have the renormalisable Yukawa couplings to tachyonic Higgs doublets needed to generate mass terms for {\it all} matter, including the vector-like leptons. The models are constrained by the requirement that twisted tadpoles cancel, that the gauge boson coupled to the weak hypercharge $U(1)_Y$ does not get a string-scale mass via a generalised Green-Schwarz mechanism, and that there are no surviving, unwanted gauged U(1) symmetries coupled to matter. Gauge coupling constant ratios close to those measured are easily obtained for reasonable values of the parameters, consistently with having the string scale close to the electroweak scale, as required to avoid the hierarchy problem. Unwanted (colour-triplet, charged-singlet, and neutral-singlet) scalar tachyons can be removed by a suitable choice of the parameters.Comment: 15 pages, LaTeX fil