Climate Change and Crop Yield Distribution: Some New Evidence From Panel Data Models

This study examines the impact of climate on the yields of seven major crops in Taiwan based on pooled panel data for 15 prefectures over the 1977-1996 period. Unit-root tests and maximum likelihood methods involving a panel data model are explored to obtain reliable estimates. The results suggest that climate has different impacts on different crops and a gradual increase in crop yield variation is expected as global warming prevails. Policy measures to counteract yield variability should therefore be carefully evaluated to protect farmers from exposure to these long-lasting and increasingly climate-related risks.Yield response, Climate change, Panel data, Unit-root test

Managing voiding dysfunction in young men

AbstractVoiding dysfunction is an uncommon condition in young men. With increased understanding of the etiology of chronic lower urinary tract dysfunction, there has been significant improvement in the management of the condition. We have reviewed the current literature and make suggestions about diagnosis, treatment, and further research on this topic. We searched the PubMed database for the management of voiding dysfunction in young men using the following terms: voiding dysfunction, lower urinary tract symptoms, young men, risk factor, urodynamics study, uroflowmetry, magnetic resonance imaging, primary bladder neck obstruction/bladder neck dysfunction, dysfunctional voiding/pseudodyssynergia, impaired detrusor contractility/detrusor underactivity, adrenergic antagonist, transurethral incision, urotherapy, baclofen, and botulinum toxin. Uroflowmetry is an important noninvasive examination for screening young men for possible voiding dysfunction. A videourodynamic study is recommended for patients with low urine flow. Primary bladder neck obstruction and dysfunctional voiding are the two most common diagnoses. α-Adrenergic antagonists and urotherapy are widely used for treating bladder neck obstruction and dysfunctional voiding, respectively. Botulinum toxin A may become a potential therapeutic option in the future. Although the published reports usually included a small number of patients and lacked randomization and a placebo-controlled group, these clinical studies still provide great advances in managing voiding dysfunction in young men. Further well-designed studies are warranted to support optimal management of these conditions

Fabrication, modeling, and characterization of form-birefringent nanostructures

A 490-nm-deep nanostructure with a period of 200 nm was fabricated in a GaAs substrate by use of electron-beam lithography and dry-etching techniques. The form birefringence of this microstructure was studied numerically with rigorous coupled-wave analysis and compared with experimental measurements at a wavelength of 920 nm. The numerically predicted phase retardation of 163.3 degrees was found to be in close agreement with the experimentally measured result of 162.5 degrees, thereby verifying the validity of our numerical modeling. The fabricated microstructures show extremely large artificial anisotropy compared with that available in naturally birefringent materials and are useful for numerous polarization optics applications

ON THE EQUIVALENCE OF IMPORT TARIFF AND QUOTA: THE CASE OF RICE IMPORT IN TAIWAN

This paper extends the existing theory on the equivalence of import tariff and quota. If the equivalence is defined on the domestic price level (weak equivalence), then either the zero conjectural variation for domestic country or a perfectly competitive market will be sufficient to support this equivalence. If the equivalence is defined both on the same domestic price level as well as tariff rate (strong equivalence), then the conditions are that either domestic country acts as a Cournot competitor and foreign country is a price taker, or both domestic and foreign country are price takers. An empirical spatial-equilibrium trade model is constructed to simulate the impacts of import tariff and quota. Using Taiwan¡¦s rice import as an example, the empirical results show that if Taiwan switches from the quota system to tariff system, the domestic rice price as well as total social welfare can be increased given the same import volume.International Relations/Trade,