Accounting for changes in the homeownership rate

After three decades of being relatively constant, the homeownership rate increased over the 1994–2005 period to attain record highs. The objective of this paper is to account for the observed boom in ownership by examining the role played by changes in demographic factors and innovations in the mortgage market that lessened down payment requirements. To measure the aggregate and distributional impact of these factors, we construct a quantitative general equilibrium overlapping-generation model with housing. We find that the long-run importance of the introduction of new mortgage products for the aggregate homeownership rate ranges from 56 percent to 70 percent. Demographic factors account for between 16 percent and 31 percent of the change. Transitional analysis suggests that demographic factors play a more important but not dominant role farther from the long-run equilibrium. From a distributional perspective, mortgage market innovations have a larger impact on participation rate changes of younger households, and demographic factors seem to be the key to understanding the participation rate changes of older households. Our analysis suggests that the key to understanding the increase in the homeownership rate is the expansion of the set of mortgage contracts. We test the robustness of this result by considering changes in mortgage financing after World War II. We find that the introduction of the conventional fixed-rate mortgage, which replaced balloon contracts, accounts for at least 50 percent of the observed increase in homeownership during that period.

"Accounting for Changes in the Homeownership Rate"

After years of being relatively constant, the homeownership rate -a target for housing policy- has increased since 1995. This paper attempts to understand why the homeownership rate has been increasing by constructing a quantitative model and then using this model to evaluate explanations that have been offered to account for this increase. We find that the increase in the homeownership can be explained by innovations in the mortgage market that allows households to take a positive housing investment position with a much smaller downpayment.

Anodal tDCS over the medial prefrontal cortex enhances behavioral adaptation after punishments during reversal learning through increased updating of unchosen choice options

The medial prefrontal cortex (mPFC) is thought to be central for flexible behavioral adaptation. However, the causal relationship between mPFC activity and this behavior is incompletely understood. We investigated whether transcranial direct current stimulation (tDCS) over the mPFC alters flexible behavioral adaptation during reward-based decision-making, targeting Montreal Neurological Institute (MNI) coordinates X = -8, Y = 62, Z = 12, which has previously been associated with impaired behavioral adaptation in alcohol-dependent patients. Healthy human participants (n = 61) received either anodal (n = 30) or cathodal (n = 31) tDCS versus sham tDCS while performing a reversal learning task. To assess the mechanisms of reinforcement learning (RL) underlying our behavioral observations, we applied computational models that varied with respect to the updating of the unchosen choice option. We observed that anodal stimulation over the mPFC induced increased choice switching after punishments compared with sham stimulation, whereas cathodal stimulation showed no effect on participants' behavior compared with sham stimulation. RL revealed increased updating of the unchosen choice option under anodal as compared with sham stimulation, which accounted well for the increased tendency to switch after punishments. Our findings provide a potential model for tDCS interventions in conditions related to flexible behavioral adaptation, such as addiction

Infection tracking in travellers using a mobile app (ITIT): the pilot study

BACKGROUND: Current surveillance of travellers' health captures only a small proportion of illness events. We aimed to evaluate the usability and feasibility of using an app to enable travellers to self-report illness. METHOD: This pilot study assesses a novel mobile application called Infection Tracking in Travellers (ITIT) that records travel-related symptoms with associated geolocation and weather data. Participants were recruited in three Swiss travel clinics between December 2021 and March 2022. A feedback survey was used to examine app ease of use, and data from the app was used to examine travel and illness patterns as a proof-of-concept for the larger ITIT study. RESULTS: Participants were recruited from Zurich, Basel, and Geneva, with 37 individuals completing a total of 394 questionnaires in 116 locations in Asia, Africa, the Americas, and Europe. Illness symptoms were reported by 41% of participants, 67% of which were respiratory. The post travel questionnaire showed that all participants found the app easy to use and 63% said they would recommend it to others. Several users provided suggestions for improved usability. CONCLUSION: The app fulfilled its function as a research tool linking infection symptoms with geolocation and climate data

Dealloying of Platinum-Aluminum Thin Films Part II. Electrode Performance

Highly porous Pt/Al thin film electrodes on yttria stabilized zirconia electrolytes were prepared by dealloying of co-sputtered Pt/Al films. The oxygen reduction capability of the resulting electrodes was analyzed in a solid oxide fuel cell setup at elevated temperatures. During initial heating to 523 K exceptionally high performances compared to conventional Pt thin film electrodes were measured. This results from the high internal surface area and large three phase boundary length obtained by the dealloying process. Exposure to elevated temperatures of 673 K or 873 K gave rise to degradation of the electrode performance, which was primarily attributed to the oxidation of remaining Al in the thin films.Comment: 5 pages, 4 figure

The effects of life stress and neural learning signals on fluid intelligence.

Fluid intelligence (fluid IQ), defined as the capacity for rapid problem solving and behavioral adaptation, is known to be modulated by learning and experience. Both stressful life events (SLES) and neural correlates of learning [specifically, a key mediator of adaptive learning in the brain, namely the ventral striatal representation of prediction errors (PE)] have been shown to be associated with individual differences in fluid IQ. Here, we examine the interaction between adaptive learning signals (using a well-characterized probabilistic reversal learning task in combination with fMRI) and SLES on fluid IQ measures. We find that the correlation between ventral striatal BOLD PE and fluid IQ, which we have previously reported, is quantitatively modulated by the amount of reported SLES. Thus, after experiencing adversity, basic neuronal learning signatures appear to align more closely with a general measure of flexible learning (fluid IQ), a finding complementing studies on the effects of acute stress on learning. The results suggest that an understanding of the neurobiological correlates of trait variables like fluid IQ needs to take socioemotional influences such as chronic stress into account

Travel-Associated Zika Virus Disease Acquired in the Americas Through February 2016

BACKGROUND: Zika virus has spread rapidly in the Americas and has been imported into many nonendemic countries by travelers. OBJECTIVE: To describe clinical manifestations and epidemiology of Zika virus disease in travelers exposed in the Americas. DESIGN: Descriptive, using GeoSentinel records. SETTING: 63 travel and tropical medicine clinics in 30 countries. PATIENTS: Ill returned travelers with a confirmed, probable, or clinically suspected diagnosis of Zika virus disease seen between January 2013 and 29 February 2016. MEASUREMENTS: Frequencies of demographic, trip, and clinical characteristics and complications. RESULTS: Starting in May 2015, 93 cases of Zika virus disease were reported. Common symptoms included exanthema (88%), fever (76%), and arthralgia (72%). Fifty-nine percent of patients were exposed in South America; 71% were diagnosed in Europe. Case status was established most commonly by polymerase chain reaction (PCR) testing of blood and less often by PCR testing of other body fluids or serology and plaque-reduction neutralization testing. Two patients developed Guillain–Barre syndrome, and 3 of 4 pregnancies had adverse outcomes (microcephaly, major fetal neurologic abnormalities, and intrauterine fetal death). LIMITATION: Surveillance data collected by specialized clinics may not be representative of all ill returned travelers, and denominator data are unavailable. CONCLUSION: These surveillance data help characterize the clinical manifestations and adverse outcomes of Zika virus disease among travelers infected in the Americas and show a need for global standardization of diagnostic testing. The serious fetal complications observed in this study highlight the importance of travel advisories and prevention measures for pregnant women and their partners. Travelers are sentinels for global Zika virus circulation and may facilitate further transmission

Liquidity and real activity in a simple open economy model

We examine nominal and real exchange rates, interest rates, prices, and evolutions of real variables in a two-country, monetary general-equilibrium model that includes a financial sector and shocks to technologies and money growth rates. Qualitative properties of the model are provided and moment predictions from a calibrated version of the model are compared to moments of time series drawn from actual economies. We focus on international monetary shock transmissions, and effects of monetary innovations on nominal and real exchange rates and nominal interest rates.Business cycles ; Liquidity (Economics)

Liquidity and real activity in three monetary models

This paper investigates interest rate determination and evolutions of nominal and real variables in alternative monetary, general equilibrium models. Three approaches to characterizing monetary transactions services are utilized: a cash-in-advance approach, in which agents face cash constraints on goods purchases; a transaction-cost approach, in which goods are sacrificed in transactions; and a shopping-time approach, in which leisure is sacrificed in transactions. Models which employ these approaches are used to examine liquidity effects of monetary innovations on interest rates and real activity.Liquidity (Economics) ; Monetary policy