Trade costs, 1870–2000

What has driven trade booms and trade busts in the past century and a half? Was it changes in global output or in the costs of international trade? To address this question, we derive a micro-founded measure of aggregate bilateral trade costs based on a standard model of trade in differentiated goods. These trade costs gauge the difference between observed bilateral trade and frictionless trade in terms of an implied markup on retail prices of foreign goods. Thus, we are able to estimate the combined magnitude of tariffs, transportation costs, and all other macroeconomic frictions that impede international trade but that are inherently difficult to observe. We use this measure to examine the growth of global trade between 1870 and 1913, its retreat from 1921 to 1939, and its subsequent rise from 1950 to 2000. We find that trade cost declines explain roughly 55 percent of the pre–World War I trade boom and 33 percent of the post–World War II trade boom, while a precipitous rise in trade costs explains the entire interwar trade bust

Trigonometric Parallaxes for 1,507 Nearby Mid-to-Late M-dwarfs

The MEarth survey is a search for small rocky planets around the smallest, nearest stars to the Sun as identified by high proper motion with red colors. We augmented our planetary search time series with lower cadence astrometric imaging and obtained two million images of approximately 1800 stars suspected to be mid-to-late M dwarfs. We fit an astrometric model to MEarth's images for 1507 stars and obtained trigonometric distance measurements to each star with an average precision of 5 milliarcseconds. Our measurements, combined with the 2MASS photometry, allowed us to obtain an absolute K_s magnitude for each star. In turn, this allows us to better estimate the stellar parameters than those obtained with photometric estimates alone and to better prioritize the targets chosen to monitor at high cadence for planetary transits. The MEarth sample is mostly complete out to a distance of 25 parsecs for stars of type M5.5V and earlier, and mostly complete for later type stars out to 20 parsecs. We find eight stars that are within ten parsecs of the Sun for which there did not exist a published trigonometric parallax distance estimate. We release with this work a catalog of the trigonometric parallax measurements for 1,507 mid-to-late M-dwarfs, as well as new estimates of their masses and radii.Comment: ApJ, accepted. 36 pages, 8 figures, 2 tables. Please find our data table here: http://www.cfa.harvard.edu/MEarth/DataDR2.htm

Proximity-Coupled Ti/TiN Multilayers for use in Kinetic Inductance Detectors

We apply the superconducting proximity effect in TiN/Ti multi-layer films to tune the critical temperature, Tc, to within 10 mK with high uniformity (less than 15 mK spread) across a 75 mm wafer. Reproducible Tc's are obtained from 0.8 - 2.5 K. These films had high resistivities, > 100 uOhm-cm and internal quality factors for resonators in the GHz range on the order of 100k and higher. Both trilayers of TiN/Ti/TiN and thicker superlattice films were prepared, demonstrating a highly controlled process for films over a wide thickness range. Detectors were fabricated and showed single photon resolution at 1550 nm. The high uniformity and controllability coupled with the high quality factor, kinetic inductance, and inertness of TiN make these films ideal for use in frequency multiplexed kinetic inductance detectors and other potential applications such as nanowire detectors, transition edge sensors and associated quantum information applications

Lessons from Katrina – What Went Wrong, What Was Learned, Who’s Most Vulnerable

If humans did not occupy the planet, disasters would never occur. Massive climatic events, earthquakes, volcanic eruptions, and tsunamis would be regular occurrences, of course, and the earth would look like a dynamic cauldron of natural activity, changing the look and the balance of nature and natural events continuously and randomly. What morphs these natural phenomenon into catastrophic events we call “disasters” is simply the presence of human beings who by choice, chance, or necessity find themselves in harm’s way. The “human factors” may be straightforward and benign. For instance, people making their livelihood from the sea are at risk from coastal storms and tsunamis. Similarly, people are found living in areas at considerable risk for mudslides and volcanoes. It could even be said that living in New Orleans, a coastal city actually below sea level, is a gamble, as was so dramatically emphasized by the storms and subsequent flooding of August and September 2005

Recovery Research, Katrina's Fifth Anniversary, and Lessons Relearned

What may be called “disaster science” is a broad field that begins with understanding hazards, risks, and population vulnerabilities and moves on to establishing best-practice models of response, mitigation, and recovery. Gaps abound in our collective knowledge in all of these areas, and it is fair to suggest that we have only begun to scratch the surface in terms of what we need to know. The goal continues to be to learn how to prevent disasters whenever possible and, when prevention is not possible, to at least optimize survival, preserve vital infrastructure, and return rapidly to a state of normalcy

Hurricane Sandy: Lessons Learned, Again

Hurricane Sandy was a sobering reminder to those of us who call New York home that it is a port city and subject to the whims of wind and water. The storm itself was massive: climatologically, a thousand miles wide at its peak; economically, an estimated excess of $50 billion in damages. In the New York metropolitan area, 97 people died in the storm, thousands were displaced from their homes, and 2 major hospitals required perilous evacuations even as the hurricane force winds engulfed the metropolitan region. For those of us in the fields of disaster medicine and public health preparedness, the question is, were we ready? During the past decade considerable public investment has been made in standardizing command and communication, assuring appropriate and rapid supply chains, and training the medical and public health workforces to respond appropriately. And yet, in the week after the storm, persistent reports of widespread gaps in the provision of coordinated relief were received from the Rockaways to Coney Island to Staten Island and New Jersey. The question was not one of capacity and capability as much as it was of communication and coordination. Resources did not always make it the last mile to reach those most in need

Prevalence and Predictors of Mental Health Distress Post-Katrina: Findings From the Gulf Coast Child and Family Health Study

Background: Catastrophic disasters often are associated with massive structural, economic, and population devastation; less understood are the long-term mental health consequences. This study measures the prevalence and predictors of mental health distress and disability of hurricane survivors over an extended period of recovery in a postdisaster setting. Methods: A representative sample of 1077 displaced or greatly affected households was drawn in 2006 using a stratified cluster sampling of federally subsidized emergency housing settings in Louisiana and Mississippi, and of Mississippi census tracts designated as having experienced major damage from Hurricane Katrina in 2005. Two rounds of data collection were conducted: a baseline face-to-face interview at 6 to 12 months post-Katrina, and a telephone follow-up at 20 to 23 months after the disaster. Mental health disability was measured using the Medical Outcome Study Short Form 12, version 2 mental component summary score. Bivariate and multivariate analyses were conducted examining socioeconomic, demographic, situational, and attitudinal factors associated with mental health distress and disability. Results: More than half of the cohort at both baseline and follow-up reported significant mental health distress. Self-reported poor health and safety concerns were persistently associated with poorer mental health. Nearly 2 years after the disaster, the greatest predictors of poor mental health included situational characteristics such as greater numbers of children in a household and attitudinal characteristics such as fatalistic sentiments and poor self-efficacy. Informal social support networks were associated significantly with better mental health status. Housing and economic circumstances were not independently associated with poorer mental health. Conclusions: Mental health distress and disability are pervasive issues among the US Gulf Coast adults and children who experienced long-term displacement or other serious effects as a result of Hurricanes Katrina and Rita. As time progresses postdisaster, social and psychological factors may play greater roles in accelerating or impeding recovery among affected populations. Efforts to expand disaster recovery and preparedness policies to include long-term social re-engagement efforts postdisaster should be considered as a means of reducing mental health sequelae

A Search for Additional Bodies in the GJ 1132 Planetary System from 21 Ground-based Transits and a 100 Hour Spitzer Campaign

We present the results of a search for additional bodies in the GJ 1132 system through two methods: photometric transits and transit timing variations of the known planet. We collected 21 transit observations of GJ 1132b with the MEarth-South array since 2015. We obtained 100 near-continuous hours of observations with the $Spitzer$ Space Telescope, including two transits of GJ 1132b and spanning 60\% of the orbital phase of the maximum period at which bodies coplanar with GJ 1132b would pass in front of the star. We exclude transits of additional Mars-sized bodies, such as a second planet or a moon, with a confidence of 99.7\%. When we combine the mass estimate of the star (obtained from its parallax and apparent $K_s$ band magnitude) with the stellar density inferred from our high-cadence $Spitzer$ light curve (assuming zero eccentricity), we measure the stellar radius of GJ 1132 to be $0.2105^{+0.0102}_{-0.0085} R_\odot$, and we refine the radius measurement of GJ 1132b to $1.130 \pm 0.056 R_\oplus$. Combined with HARPS RV measurements, we determine the density of GJ 1132b to be $6.2 \pm 2.0$\ g cm$^{-3}$, with the mass determination dominating this uncertainty. We refine the ephemeris of the system and find no evidence for transit timing variations, which would be expected if there was a second planet near an orbital resonance with GJ 1132b.Comment: 29 pages, 4 Tables, 8 Figures, Submitted to ApJ. Comments welcom