402 research outputs found
Marriage, Divorce, Remarriage: The Catalyst Effect of Unilateral Divorce
Unilateral divorce catalyzes the dissolution of unstable marriages and reorganizing better ones. To examine how unilateral divorce affects marital duration, we develop a simple DID stochastic dominance comparison across legal regimes and marital cohorts. This DID comparison identifies that unilateral divorce catalyzes the dissolution of unstable marriages; more importantly, remarriages after the termination of first marriages also undergo significantly faster in the unilateral regime. We study the underlying mechanism using a parsimonious unitary model of marriage-remarriage cycle with three features: 1) on-the-job (marriage) search (OJS); 2) marital investment; 3) OJS feedbacks as an exogenous spousal separation event in the equilibrium. Under unilateral divorce, the lowered time cost involved in separation results in front-loaded OJS
Marriage, Divorce, Remarriage: The Catalyst Effect of Unilateral Divorce
Unilateral divorce catalyzes the dissolution of unstable marriages and reorganizing better ones. To examine how unilateral divorce affects marital duration, we develop a simple DID stochastic dominance comparison across legal regimes and marital cohorts. This DID comparison identifies that unilateral divorce catalyzes the dissolution of unstable marriages; more importantly, remarriages after the termination of first marriages also undergo significantly faster in the unilateral regime. We study the underlying mechanism using a parsimonious unitary model of marriage-remarriage cycle with three features: 1) on-the-job (marriage) search (OJS); 2) marital investment; 3) OJS feedbacks as an exogenous spousal separation event in the equilibrium. Under unilateral divorce, the lowered time cost involved in separation results in front-loaded OJS
Conspicuous Consumption and Within-Group Income Inequality
Individuals engage in conspicuous consumption to signal
their income to their own reference groups, defined in a fine
manner by observable identifiers such as race, gender, education,
and occupation. The more income inequality within a reference
group, the less prior information concerning the income
of an individual, and hence the more effective the conspicuous
consumption signal. Therefore, within-group income inequality
causes substitution from non-conspicuous consumption to conspicuous
consumption. We find strong evidence supporting this
prediction regarding aggregate conspicuous consumption for all
income percentiles. Disaggregating into smaller consumption
categories, most consumption items categorized by the previous
literature as conspicuous and non-conspicuous using survey
methods agrees with this prediction as well
Conspicuous Consumption and Within-Group Income Inequality
Individuals engage in conspicuous consumption to signal
their income to their own reference groups, defined in a fine
manner by observable identifiers such as race, gender, education,
and occupation. The more income inequality within a reference
group, the less prior information concerning the income
of an individual, and hence the more effective the conspicuous
consumption signal. Therefore, within-group income inequality
causes substitution from non-conspicuous consumption to conspicuous
consumption. We find strong evidence supporting this
prediction regarding aggregate conspicuous consumption for all
income percentiles. Disaggregating into smaller consumption
categories, most consumption items categorized by the previous
literature as conspicuous and non-conspicuous using survey
methods agrees with this prediction as well
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Direct grafting of tetraaniline via perfluorophenylazide photochemistry to create antifouling, low bio-adhesion surfaces.
Conjugated polyaniline has shown anticorrosive, hydrophilic, antibacterial, pH-responsive, and pseudocapacitive properties making it of interest in many fields. However, in situ grafting of polyaniline without harsh chemical treatments is challenging. In this study, we report a simple, fast, and non-destructive surface modification method for grafting tetraaniline (TANI), the smallest conjugated repeat unit of polyaniline, onto several materials via perfluorophenylazide photochemistry. The new materials are characterized by nuclear magnetic resonance (NMR) and electrospray ionization (ESI) mass spectroscopy. TANI is shown to be covalently bonded to important carbon materials including graphite, carbon nanotubes (CNTs), and reduced graphene oxide (rGO), as confirmed by transmission electron microscopy (TEM). Furthermore, large area modifications on polyethylene terephthalate (PET) films through dip-coating or spray-coating demonstrate the potential applicability in biomedical applications where high transparency, patternability, and low bio-adhesion are needed. Another important application is preventing biofouling in membranes for water purification. Here we report the first oligoaniline grafted water filtration membranes by modifying commercially available polyethersulfone (PES) ultrafiltration (UF) membranes. The modified membranes are hydrophilic as demonstrated by captive bubble experiments and exhibit extraordinarily low bovine serum albumin (BSA) and Escherichia coli adhesions. Superior membrane performance in terms of flux, BSA rejection and flux recovery after biofouling are demonstrated using a cross-flow system and dead-end cells, showing excellent fouling resistance produced by the in situ modification
Comment on “The complex effects of ocean acidification on the prominent N2-fixing cyanobacterium Trichodesmium”
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Science 357 (2017): eaao0067, doi:10.1126/science.aao0067.Hong et al. (Reports, 5 May 2017, p. 527) suggested that previous studies of the biogeochemically significant marine cyanobacterium Trichodesmium showing increased growth and nitrogen fixation at projected future high CO2 levels suffered from ammonia or copper toxicity. They reported that these rates instead decrease at high CO2 when contamination is alleviated. We present and discuss results of multiple published studies refuting this toxicity hypothesis
Effects of alterations of primer-binding site sequences on human immunodeficiency virus type 1 replication
The human immunodeficiency virus type 1 genomic RNA primer-binding site (PBS) sequence comprises 18 nucleotides which are complementary to those at the 3\u27 end of the replication initiation primer tRNA(3Lys). To investigate the role of the PBS in viral replication, we either deleted the original wild-type PBS (complementary to tRNA(3Lys) or replaced it with DNA sequences complementary to either tRNA(1,2Lys) or tRNA(Phe). Transfection of COS cells with such molecular constructs yielded similar levels of viral progeny that were indistinguishable with regard to viral proteins and tRNA content. Virus particles derived from PBS-deleted molecular clones were noninfectious for MT-4, Jurkat, and CEM-T4 cells. However, infectious viruses were derived from constructs in which the PBS had been altered to sequences complementary to either tRNA(1,2Lys) or tRNA(Phe), although mutated forms showed significant lags in replication efficiency in comparison with wild types. Molecular analysis of reverse-transcribed DNA in cells infected by the mutated viruses indicated that both tRNA(1,2Lys) and tRNA(Phe) could function as primers for reverse transcription during the early stages of infection. Sequencing of full-length proviral DNA, obtained 6 days after infection, revealed the mutated PBS, indicating that a complete cycle of reverse transcription had occurred. During subsequent rounds of infection, reversion of the mutated PBS to wild-type sequences was observed, accompanied by increased production of viral gene products. Reversion to wild-type PBS sequences was confirmed both by specific PCR analysis, using distinct primer pairs, and by direct sequencing of amplified segments. We also performed endogenous in vitro reverse transcription experiments in which synthesis of minus-strand strong-stop viral DNA was primed from a synthetic RNA template containing a PBS complementary to various tRNA isoacceptors. These results showed that tRNA(3Lys) was a much more efficient primer of such reactions than either tRNA(1,2Lys) or tRNA(Phe).<br /
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