Controlling for heterogeneity in gravity models of trade and integration

This paper compares various specifications of the gravity model of trade as nested versions of a general specification that uses bilateral country-pair fixed effects to control for heterogeneity. For each specification, we show that the atheoretical restrictions used to obtain them from the general model are not supported statistically. Because the gravity model has become the "workhorse" baseline model for estimating the effects of international integration, this has important empirical implications. In particular, we show that, unless heterogeneity is accounted for correctly, gravity models can greatly overestimate the effects of integration on the volume of trade.International trade

Controlling for heterogeneity in gravity models of trade and integration

This paper compares various specifications of the gravity model of trade as nested versions of a general specification that uses bilateral country-pair fixed effects to control for heterogeneity. For each specification, we show that the a theoretical restrictions to obtain them from the general model are not supported statistically. Because the gravity model has become the ‘workhorse’ baseline model for estimating the effects of international integration, this has important empirical implications. In particular, we show that, unless heterogeneity is accounted for correctly, gravity models can greatly overestimate the effects of integration on the volume of trade.International trade

Matrix Norms

In many situations it is very useful to have a single nonnegative real number to be, in some sense, the measure of the size of a vector or a matrix. As a matter of fact we do a similiar thing with scalars, we let jÀj represent the familiar absolute value or modulus of À. Fora vector x e: C , one way n of assigning magnitude is the usual definition of length, Il I 1/2 2 1/2 xl= = {jxij } , which is called the euclidean norm of x. In this case, length gives an overall estimate of the size of the elements of x. If llxll is large, at least one of the elements in x is large, and vise versa. There are many ways of defining norms for vectors and matrices. We will examine some of these in this paper

Research on Safety and Security Distance of Flammable Liquid Storage Tank

AbstractFlammable liquid storage tanks usually plant a potential dangerous zone. The damage gets worse and worse. In order to avoid the tank fire, the tanks extended to the nearby storage tanks-facilities and buildings. In consideration of safety conditions, flammable liquid storage tanks for the safety and security distance is necessary. Through the FDS (Fire Dynamics Simulator) computer simulation of fire, flammable liquid storage tanks for spot the fires numerical simulation to detect a fire to happen. In order to establish an optimized model, the flammable liquid storage tanks save the temperature distribution by obtaining flammable safety distance of the liquid storage tank, by talking about the current laws and regulations, by looking forward to meeting the economic and security considerations

NEW START: THE LIFE EXPERIENCES OF RECOVERING SUICIDAL ADOLESCENTS

Background: Suicide is a serious global health problem and the second leading cause of death for adolescents in Taiwan. Previous studies have typically explored the causes of suicide; however, scant research has considered suicide recovery contexts, leading to the inability to developing effective suicide prevention strategies.Aim: Exploring the life experiences of adolescents during their suicide recovery processes.Method: A descriptive phenomenology research design was employed. The participants comprised 6 outpatient young adult who possessed histories of suicide and recovering from attempted suicide. Semi-structured, one-on-one in-depth interviews were conducted and Colaizzi’s (1978) methods were used for data analysis. Results: The main identified dimension was “new start” which comprised the following five major themes: conversion of suicidal thoughts, awareness of change, loving attachments, the emotional regulation, and the future prospects. Conclusion: Although adolescents are a high-risk population for suicide, they demonstrate recovery power. The results of this study should provide a reference for professional personnel to assist teenagers in recognizing and using internal and external resources, discovering the value of life and hopes for the future, and reducing the risk of suicide

Altered expression of protein tyrosine phosphatase, non-receptor type 22 isoforms in systemic lupus erythematosus

Introduction: A C-to-T single nucleotide polymorphism (SNP) located at position 1858 of human protein tyrosine phosphatase, non-receptor type 22 (PTPN22) complementary DNA (cDNA) is associated with an increased risk of systemic lupus erythematosus (SLE). How the overall activity of PTPN22 is regulated and how the expression of PTPN22 differs between healthy individuals and patients with lupus are poorly understood. Our objectives were to identify novel alternatively spliced forms of PTPN22 and to examine the expression of PTPN22 isoforms in healthy donors and patients with lupus. Methods: Various human PTPN22 isoforms were identified from the GenBank database or amplified directly from human T cells. The expression of these isoforms in primary T cells and macrophages was examined with real-time polymerase chain reaction. The function of the isoforms was determined with luciferase assays. Blood samples were collected from 49 subjects with SLE and 15 healthy controls. Correlation between the level of PTPN22 isoforms in peripheral blood and clinical features of SLE was examined with statistical analyses. Results: Human PTPN22 was expressed in several isoforms, which differed in their level of expression and subcellular localization. All isoforms except one were functionally interchangeable in regulating NFAT activity. SLE patients expressed higher levels of PTPN22 than healthy individuals and the levels of PTPN22 were negatively correlated with the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC-DI). Conclusions: The overall activity of PTPN22 is determined by the functional balance among all isoforms. The levels of PTPN22 isoforms in peripheral blood could represent a useful biomarker of SLE

Effects Of Dispersive 2-Photon Transitions On Femtosecond Pulse-Propagation In Semiconductor Wave-Guides

It is demonstrated that the frequency spectrum of femtosecond pulses becomes highly asymmetric when propagating as transverse magnetic modes in semiconductor multiple quantum well channel waveguides at photon energies near half the band gap. Calculations based on the frequency dispersion in two-photon transitions provide results consistent with the experiment

Inorganic Phototropism in Electrodeposition of Se-Te

Photoelectrochemical deposition of Se–Te on isolated Au islands using an unstructured, incoherent beam of light produces growth of Se–Te alloy toward the direction of the incident light beam. Full-wave electromagnetic simulations of light absorption indicated that the induced spatial growth anisotropy was a function of asymmetric absorption in the evolving deposit. Inorganic phototropic growth is analogous to biological systems such as palm trees that exhibit phototropic growth wherein physical extension of the plant guides the crown toward the time-averaged position of the sun, to maximize solar harvesting