Introduction: Children, who work or live at streets, are one of the HIV high risk groups in Iran, with no comprehensive preventive programs. This study intended to assess substance use among street children in Tehran, Capital of Iran. Methods: This paper is a part of comprehensive rapid assessment and response (RAR) research on street children in Tehran i...

Market crash is usually considered an indication that the fundamentals of the economy have changed and recession is around the corner. This, however, need not be the case. For instance, in October 1987 Wall Street lost over 20% of its value in one day, but this was not followed by a recession. Moreover, in the days preceding the crash, there were no significant external events or “bad news” tha...

Job Market Signaling and Employer Learning This paper extends the job market signaling model of Spence (1973) by allowing firms to learn the ability of their employees over time. Contrary to the model without employer learning, we find that the Intuitive Criterion does not always select a unique separating equilibrium. When the Intuitive Criterion bites and information is purely asymmetric, the...

This study extends from Liu and Mei (1992) by further investigation of assets, real estate related securities, which includes both equity and mortgage real estate investment trusts (REITs), the stocks of builderand owner-companies, and mortgagebacked securities (MBSs). There are five major findings. First, expected excess returns of real estate related securities are more predictable than the e...

We embed venture capital contracting in a search market environment where venture capitalists and entrepreneurs meet and bargain over optimal contracts. We find that both the composition and type of financial claims held by the venture capitalist and entrepreneur depend critically on the underlying market structure. In some cases both parties hold a mix of debt and equity while in others only o...

Background: The illicit vials with street name Temgesic and Norgesic has been distributed in black market of Iran in recent years. With reference to their name, one may presume that they contain the opioid Buprenorphine but there are some reports in opposition to this. True nature of these vials has been shown in the current study. Methods: All of drugs that had been apprehended by law enforce...

In a model with endogenous number of innovating firms, we show that whether patent protection increases R&D investment is ambiguous, and depends on the market demand function and the cost of R&D. If the market size increases with number of firms, patent protection reduces R&D investment if the cost of R&D is sufficiently high, and higher product differentiation increases the possibility of lowe...