A proposal for detecting the spin of a single electron in superfluid helium

The electron bubble in superfluid helium has two degrees of freedom that may offer exceptionally low dissipation: the electron's spin and the bubble's motion. If these degrees of freedom can be read out and controlled with sufficient sensitivity, they would provide a novel platform for realizing a range of quantum technologies and for exploring open questions in the physics of superfluid helium. Here we propose a practical scheme for accomplishing this by trapping an electron bubble inside a superfluid-filled opto-acoustic cavity.Comment: Main text: 5 pages, 5 figures. Supplement: 11 pages, 2 figures, 1 tabl

U.S. Demographics and Saving: Predictions of Three Saving Models

This paper compares the predictions of three different saving models with respect to the impact of projected U.S. demographic change on future U.S. saving rates. The three models are the life cycle model, the infinite horizon altruism model, and a reduced form econometric model. The findings for the different models indicate a great range of possible paths of future U.S. saving. However, the three models concur in predicting a peak in the U.S. national saving rate in the near future (within 15 years), followed by a significant decline in the saving rate thereafter. In fact, the findings suggest the strong possibility of negative U.S. saving rates beginning after 2030.

Estimating Fixed Effects: Perfect Prediction and Bias in Binary Response Panel Models, with an Application to the Hospital Readmissions Reduction Program

The maximum likelihood estimator for the regression coefficients, β, in a panel binary response model with fixed effects can be severely biased if N is large and T is small, a consequence of the incidental parameters problem. This has led to the development of conditional maximum likelihood estimators and, more recently, to estimators that remove the O(T–1) bias in β^. We add to this literature in two important ways. First, we focus on estimation of the fixed effects proper, as these have become increasingly important in applied work. Second, we build on a bias-reduction approach originally developed by Kosmidis and Firth (2009) for cross-section data, and show that in contrast to other proposals, the new estimator ensures finiteness of the fixed effects even in the absence of within-unit variation in the outcome. Results from a simulation study document favourable small sample properties. In an application to hospital data on patient readmission rates under the 2010 Affo

SGNP: An Essential Stress Granule/Nucleolar Protein Potentially Involved in 5.8s rRNA Processing/Transport

Background: Stress Granules (SG) are sites of accumulation of stalled initiation complexes that are induced following a variety of cellular insults. In a genetic screen for factors involved in protecting human myoblasts from acute oxidative stress, we identified a gene encoding a protein we designate SGNP (Stress Granule and Nucleolar Protein). Methodology/Principal Findings: A gene-trap insertional mutagenesis screen produced one insertion that conferred resistance to sodium arsenite. RT-PCR/39 RACE was used to identify the endogenous gene expressed as a GFP-fusion transcript. SGNP is localized in both the cytoplasm and nucleolus and defines a non-nucleolar compartment containing 5.8S rRNA, a component of the 60S ribosomal subunit. Under oxidative stress, SGNP nucleolar localization decreases and it rapidly co-localizes with stress granules. The decrease in nucleolar SGNP following oxidative stress was accompanied by a large increase in nucleolar 5.8S rRNA. Knockdown of SGNP with shRNA increased global mRNA translation but induced growth arrest and cell death. Conclusions: These results suggest that SGNP is an essential gene that may be involved in ribosomal biogenesis and translational control in response to oxidative stress

Expression, Purification and Characterization of Arginase from Helicobacter pylori in Its Apo Form

Arginase, a manganese-dependent enzyme that widely distributed in almost all creatures, is a urea cycle enzyme that catalyzes the hydrolysis of L-arginine to generate L-ornithine and urea. Compared with the well-studied arginases from animals and yeast, only a few eubacterial arginases have been characterized, such as those from H. pylori and B. anthracis. However, these enzymes used for arginase activity assay were all expressed with LB medium, as low concentration of Mn2+ was detectable in the medium, protein obtained were partially Mn2+ bonded, which may affect the results of arginase activity assay. In the present study, H. pylori arginase (RocF) was expressed in a Mn2+ and Co2+ free minimal medium, the resulting protein was purified through affinity and gel filtration chromatography and the apo-form of RocF was confirmed by flame photometry analysis. Gel filtration indicates that the enzyme exists as monomer in solution, which was unique as compared with homologous enzymes. Arginase activity assay revealed that apo-RocF had an acidic pH optimum of 6.4 and exhibited metal preference of Co2+>Ni2+>Mn2+. We also confirmed that heat-activation and reducing regents have significant impact on arginase activity of RocF, and inhibits S-(2-boronoethyl)-L-Cysteine (BEC) and Nω-hydroxy-nor-Arginine (nor-NOHA) inhibit the activity of RocF in a dose-dependent manner

Compulsory Military Service in Germany Revisited

This paper estimates the causal impact of compulsory military service on men in Germany using social security and pension administrative data for the cohort of individuals born in the period 1932-1942. Due to the combination of laws restricting conscription only to men born on or after July 1, 1937, difference-in-differences estimates of the effect of conscription on average daily wages can be computed using cohorts of women as a comparison group. The results indicate that conscription had no significant impact on a draftee's labor-market performance, validating an earlier result using an alternative identification strategy.Dieses Papier zeigt den kausalen Einfluss der Wehrpflicht auf Männer in Deutschland. Es werden Daten der Sozialversicherung und administrativen Pensionsdaten für die Kohorte der Individuen, die im Zeitraum von 1932 bis 1942 geboren wurden, verwendet. Aufgrund der Kombination der Gesetze zur eingeschränkten Wehrpflicht kann nur bei Männern, die am 01. Juli 1937 oder danach geboren wurden mittels des Differenz von Differenzen-Ansatzes der Effekt der Wehrpflicht auf den durchschnittlichen Tageslohn geschätzt werden. Als Vergleichsgruppe wird die Kohorte der Frauen verwendet. Die Ergebnisse zeigen, dass die Wehrpflicht keinen signifikanten Einfluss auf die Arbeitsmarktentwicklung Wehrpflichtiger hat, was ein früheres Ergebnis mit einer alternativen Identifikationsstrategie bestätigt

Should UI Eligibility Be Expanded to Low-Earning Workers? Evidence on Employment, Transfer Receipt, and Income from Administrative Data

Recent efforts to expand unemployment insurance (UI) eligibility are expected to increase low-earning workers’ access to UI. Although the expansion’s aim is to smooth the income and consumption of previously ineligible workers, it is possible that UI benefits simply displace other sources of income. Standard economic models predict that UI delays reemployment, thereby reducing wage income. Additionally, low-earning workers are often eligible for benefits from means-tested programs, which may decrease with UI benefits. In this paper, we estimate the impact of UI eligibility on employment, means-tested program participation, and income after job loss using a unique individual-level administrative data set from the state of Michigan. To identify a causal effect, we implement a fuzzy regression discontinuity design around the minimum earnings threshold for UI eligibility. Our main finding is that while UI eligibility increases jobless durations by up to 25 percent and temporarily lowers receipt of cash assistance (TANF) by 63 percent, the net impact on total income is still positive and large. In the quarter immediately following job loss, UI-eligible workers have 46-61 percent higher incomes than ineligibles

MicroRNAome of Porcine Pre- and Postnatal Development

The domestic pig is of enormous agricultural significance and valuable models for many human diseases. Information concerning the pig microRNAome (miRNAome) has been long overdue and elucidation of this information will permit an atlas of microRNA (miRNA) regulation functions and networks to be constructed. Here we performed a comprehensive search for porcine miRNAs on ten small RNA sequencing libraries prepared from a mixture of tissues obtained during the entire pig lifetime, from the fetal period through adulthood. The sequencing results were analyzed using mammalian miRNAs, the precursor hairpins (pre-miRNAs) and the first release of the high-coverage porcine genome assembly (Sscrofa9, April 2009) and the available expressed sequence tag (EST) sequences. Our results extend the repertoire of pig miRNAome to 867 pre-miRNAs (623 with genomic coordinates) encoding for 1,004 miRNAs, of which 777 are unique. We preformed real-time quantitative PCR (q-PCR) experiments for selected 30 miRNAs in 47 tissue-specific samples and found agreement between the sequencing and q-PCR data. This broad survey provides detailed information about multiple variants of mature sequences, precursors, chromosomal organization, development-specific expression, and conservation patterns. Our data mining produced a broad view of the pig miRNAome, consisting of miRNAs and isomiRs and a wealth of information of pig miRNA characteristics. These results are prelude to the advancement in pig biology as well the use of pigs as model organism for human biological and biomedical studies

Does the Swiss Car Market Reward Fuel Efficient Cars? Evidence from Hedonic Pricing Regressions, Matching and a Regression Discontinuity Design

To correct market failures due to the presence of negative externalities associated with energy consumption, governments have adopted a variety of policies, including taxes, subsidies, regulations and standards, and information-based policies. For example, labels that clearly convey energy consumption rates, associated costs, and emissions of conventional pollutants and CO2, have been devised and used in the last two decades in several countries. In 2003, Switzerland introduced a system of fuel economy labels, based on grades ranging from A to G, where is A best and G is worst, to assist consumers in making decisions that improve the fleet s fuel economy and lower emissions. We use a dataset documenting all passenger cars approved for sale in Switzerland each year from 2000 to 2011 to answer three key research questions. First, what is the willingness to pay for fuel economy? Second, do Swiss drivers - or Swiss auto importers on their behalf - appear to do a one-to-one tradeoff between car purchase price and savings on fuel costs over the lifetime of the car? Third, does the label have an additional effect on price, all else the same, above and beyond that of fuel efficiency alone? Hedonic pricing regressions that exploit the variation in fuel economy across make-models, and over time within make-models, suggest that there is a (modest) capitalization of fuel economy into car prices. The diesel premium, however, exceeds the future fuel cost savings made possible by diesel cars, even at zero discount rates. An alternate calculation suggests that the fuel economy premium is consistent with a very low discount rate (2.5%). We use a sharp regression discontinuity design (RDD) based on the mechanism used by the Swiss Federal Office of Energy to assign cars to the fuel economy label to see if the label has an independent effect on price, above and beyond that of the fuel economy. The RDD approach estimates the effect to be 6-11%. To broaden the fuel economy range over which we assess the effect of the A label, we also deploy matching estimators, and find that the effect of an A label on car price is approximately 5%