Revisiting Regional Trading Agreements with Proper Specification of the Gravity Model

This paper uses a gravity model to assess ex-post regional trade agreements. The model includes 130 countries and is estimated in panel over the period 1962-96. The introduction of the correct number of dummy variables allows for identification of Vinerian trade creation and trade diversion effects, while the estimation method takes into account a potential correlation between the explanatory variables and the bilateral specific effects introduced in the model, as well as potential selection bias. In contrast with previous estimates, results show that over the period 1962-1996, regional agreements have generated a significant increase in trade between members, often at the expense of the rest of the world.Gravity equation, Regional trade agreements, Trade creation, Trade diversion, panel data.

Regional Agreements and Welfare in the South:When Scale Economies in Transport Matter

This paper evidences that the accepted pessimistic view, in terms of welfare, of regional trade agreements between developing countries can be challenged by scale economies in transport. This paper focuses on two main issues. First, how is the standard welfare analysis of regional trade agreement affected by the endogeneity of transport costs (i.e. by the joint determination of trade quantities and transport costs)? Second, what are the long-run consequences of endogenous transport costs for welfare if worldwide free trade is achieved through preferential trade agreements? This paper extends the Spilimbergo and Stein (1998)'s model of interindustry trade (generated by relative factors endowment differences) intraindustry trade (generated by scale and product-diversity effects) and iceberg transport costs. In addition of assuming a "hub-and-spoke" transport network structure, we also consider that transport costs depend on the distance between trade partners (three types of costs are defined: regional, continental and across ocean) and on their development level. Most importantly, we allow for an explicit treatment of the transport sector. The main conclusion is that, with scale economies in transport, regional liberalization will have persistent effect on trade flows through irreversible effect on regional transport costs that improve the final welfare, for a developing country, under regional free trade agreement as well as under worldwide free trade.Economies of Scale., Transport Costs, Welfare, regional integration

Mapping the Epoch of Reionization with C+ Line Tomography

Our KISS program has laid the theoretical foundations for probing the epoch of reionization with C+ tomography measurements, developed unique lithographed millimeter-wave spectrometer technology, and initiated a first-light C+ experiment named TIME-Pilot. With KISS support we have carried out the following investigations: 1) Developed the case for line intensity mapping methods to study the epoch of reionization using singly ionized carbon (C+), typically the most luminous emission line in galaxies. The theoretical studies not only explored the amplitude of the signal, and the usefulness in determining physical properties of the partially ionized intergalactic medium, but also the effects of foreground confusion from low-redshift galaxies. Our team made the first calculations of C+ clustering fluctuations from the reionization epoch, and estimated the effect of foreground galaxy confusion, largely from CO line emission at z ~ 1. We also authored the first papers on tomographic measurements with the Ly emission line, which shows great promise for near-infrared intensity mapping measurements with the SPHEREx SMEX mission concept. 2) Developed a complete design for a first-detection instrument of [CII] large-scale clustering emission named TIME-Pilot, based on an array of 32 novel waveguide spectrometers. The spectrometers are mounted in a linear array in two polarizations, and observations are carried out by scanning the detectors in a 1-deg linear strip, which maximizes depth (small survey area) while preserving sensitivity on large scales (long scan length). 3) Demonstrated the key waveguide spectrometer technology, which confines radiation in 2 dimensions and the power propagates between parallel plates and is dispersed and collimated by a curved grating. The waveguide spectrometers greatly reduce the mass and volume that would otherwise be required with a conventional 3-d grating spectrometer. 4) Demonstrated a prototype superconducting detector array. These high-sensitivity superconducting bolometers are mounted on the focal surface across multiple spectrometers, and read out by superconducting current amplifiers. The devices present unique micro-machining challenges to produce edge-butted sub-arrays that do not leave spectral gaps between channels. 5) Completed the full cryogenic system for the instrument. We commandeered an existing 4 K cryostat from another project, and added cooling stages to an ultimate temperature of 220 mK to meet the TIME-Pilot cooling requirements. The system is fully tested and operational. 6) Formed a partnership with ASIAA in Taiwan, led by Tzu-Ching Chang who attended the original KISS study. ASIAA is providing major hardware components for the TIME-Pilot instrument, and in the past year have developed a prototype of the spectrometer, and procured cables and cryogenic coolers. ASIAA has also become the managing institution for the James Clerk Maxwell Telescope (JCMT) in Hawaii, and ideal facility for carrying out observations with the instrument

Induced local spin-singlet amplitude and pseudogap in high TcT_{c} cuprates

In this paper we show that local spin-singlet amplitude with d-wave symmetry, , can be induced by short-range spin correlations even in the absence of pairing interactions. Fluctuation theory is formulated to make connection between pseudogap temperature $T^{*}$, pseudogap size $\Delta_{pg}$ and . In the present scenario for the pseudogap, the normal state pseudogap is caused by the induced local spin-singlet amplitude due to short-range spin correlations, which compete in the low energy sector with superconducting correlations to make $T_{c}$ go to zero near half-filling. Calculated $T^{*}$ falls from a high value onto the $T_{c}$ line and closely follows mean-field N\'{e}el temperature $T_{N}^{MF}$. The calculated $\Delta_{pg}$ is in good agreement with experimental results. We propose an experiment in which the present scenario can be critically tested.Comment: 5 pages, 3 figure

Comparison of Circulating Concentrations of Reproductive Hormones in Boars of Lines Selected for Size of Testes or Number of Ovulations and Embryonal Survival to Concentrations in Respective Control Lines

The objectives of this study were to determine whether circulating concentrations of gonadotropins and gonadal hormones of boars were altered as a result of selection of pigs for size of testes or for embryonal survival and(or) number of ovulations. Included in Exp. 1 and 2 were boars with the greatest estimated paired weight of testes (TS) and boars from a control (C) line. Concentrations of FSH were similar ( P \u3e .10) in boars from the TS and C lines. In Exp. 3, 4, and 5, circulating concentrations of FSH and 17β-estradiol (E2) were evaluated in neonates, during pubertal development, and in mature boars of lines selected for an index of number of ovulations and embryonal survival ( I ) , and data were compared to those for boars from a respective C line. Concentrations of E2 were not different in boars from the I line and those from the C line during the early neonatal period but were greater ( P \u3c .05) in boars of the C line than in those from the I line during pubertal development. Concentrations of FSH were greater ( P \u3c .05) in mature boars from the I line than in those from the C line. In summary, selection for size of testes did not influence circulating concentrations of FSH in mature boars. The secretory pattern of E2 in boars before puberty changed as a result of selection for embryonal survival and number of ovulations in females of the I line, and the different patterns of circulating E2 early in life may result in enhanced circulating concentrations of FSH in adult boars of the I line compared with boars of the C line

Single-gene Effects on Body Weight in Selected and Unselected Mouse Lines Detected by Bayesian Marker-free Segregation Analysis

Segregation analysis of body weight at 21, 42, and 63 days in eleven generations of unselected (2813 individuals  of C line) and selected (1410 individuals of HGC line, derived from C line) mice was performed.  The Gibbs sampling algorithm was applied to obtain posterior density distributions of model parameters.  Moderate heritability via polygenic model was estimated. The results suggest a mixed inheritance model  (major gene + polygenic) for the body weight. The proportion of single gene variance to phenotypic variance  ranged from 9.7 to 41 percent. The estimated additive heritabilities for these traits varied between 0.25  and 0.47 for the C line and 0.37 and 0.41 for the HGC line. Considerable differences in estimated major  gene frequencies were found between unselected and selected lines.

Detection of Neutral Carbon in the M 31 Dark Cloud D478

Emission from the 492 GHz CI tranition was detected towards the dark cloud D478 in M31. Using existing 12CO and 13CO measurements, models for the gas properties of D478 are discussed. The observed CO and C line ratios can be explained by two-component models (dense cores and tenuous envelopes); single-density models appear less likely. The models indicate temperatures T(kin) = 10 K. The beam-averaged C column density is 0.3 - 0.8 times that of CO, whereas the total carbon to hydrogen ratio N(C)/N(H) = 5-3 times 10**-4. The resulting CO-to-H2 conversion factor X is about half that of the Solar Neighbourhood. With temperatures of about 10 K and projected mass densities of 5-10 M(sun)/pc**2 there appears to be no need to invoke the presence of very cold and very massive clouds. Rather, D478 appears to be comparable to Milky Way dark cloud complexes such as the Taurus-Auriga dark cloud complex.Comment: 7 Pages, 1 Figure; accepted by A&