Contracting the Facebook API

In recent years, there has been an explosive growth in the popularity of online social networks such as Facebook. In a new twist, third party developers are now able to create their own web applications which plug into Facebook and work with Facebook's "social" data, enabling the entire Facebook user base of more than 400 million active users to use such applications. These client applications can contain subtle errors that can be hard to debug if they misuse the Facebook API. In this paper we present an experience report on applying Microsoft's new code contract system for the .NET framework to the Facebook API.We wrote contracts for several classes in the Facebook API wrapper which allows Microsoft .NET developers to implement Facebook applications. We evaluated the usefulness of these contracts during implementation of a new Facebook application. Our experience indicates that having code contracts provides a better and quicker software development experience.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330

The renal effect of low-dose dopamine in high-risk patients undergoing coronary angiography

AbstractOBJECTIVESThe purpose of the study was to examine the potential renal protective effect of low-dose dopamine in high-risk patients undergoing coronary angiography.BACKGROUNDContrast nephropathy is prevalent in patients with chronic renal failure (CRF) and/or diabetes mellitus (DM). Decreased renal blood flow due to vasoconstriction was suggested as a contributory mechanism. Low-dose dopamine has a dilatory effect on the renal vasculature.METHODSSixty-six patients with mild or moderate CRF and/or DM undergoing coronary angiography were prospectively double-blindedly randomized, to either 120 ml/day of 0.9% saline plus dopamine 2 μg/kg/min (Dopamine group) or saline alone (Control group) for 48 h.RESULTSThirty-three Dopamine-treated (30 diabetics and 6 with CRF) and 33 Control (28 diabetics and 5 with CRF) patients were compared. Plasma creatinine (Cr) level increased in the Control group from 100.6 ± 5.2 before to 112.3 ± 8.0 μmol/liter within five days after angiography (p = 0.003), and in the Dopamine group from 100.3 ± 5.4 before to 117.5 ± 8.8 μmol/liter after angiography (p = 0.0001), respectively. There was no significant difference in the changeof Cr level (ΔCr) between the two groups. However, in a subgroup of patients with peripheral vascular disease (PVD), ΔCr was −2.4 ± 2.3 in the Control group and 30.0 ± 12.0 μmol/liter in the Dopamine group (p = 0.01). No significant difference occurred in ΔCr between Control and Dopamine in subgroups of patients with preangiographic CRF or DM.CONCLUSIONSContrast material caused a small but significant increase in Cr blood level in high-risk patients. There is no advantage of dopamine over adequate hydration in patients with mild to moderate renal failure or DM undergoing coronary angiography. Dopamine should be avoided in patients with PVD exposed to contrast medium