Less is More Usable: Measuring Security Usability as Energy Efficiency

Efficiency in thermodynamics is measured based on the 1st Law of Thermodynamics: Energy is neither created nor destroyed. The efficiency of a mechanical interface is the quotient of the useful energy and the energy expended to operate the machine. When humans use computer interfaces they expend both kinetic and cognitive energy to successfully navigate to the desired result. Security usability presents a more unique problem than usability of typical computer interfaces. Unlike most functionality in computer interfaces, navigating security is an interruption to the primary objective. If the security is sufficiently disruptive to progress toward the primary objective, a user will either go around the security, or turn it off. Applying the 1st Law of Thermodynamics to the interaction of humans with computer security interfaces could improve usability by increasing efficiency, and reducing the motivation to avoid security

Quantifying the ex-post causal impact of differential pricing on commuter trip scheduling in Hong Kong

This paper quantifies the causal impact of differential pricing on the trip-scheduling of regular commuters using the Mass Transit Railway (MTR) in Hong Kong. It does so by applying a difference-in-difference (DID) method to large scale smart card data before and after the introduction of the Early Bird Discount (EBD) pricing intervention. We find statistically significant but small effects of the EBD in the form of earlier departure times. Leveraging the granularity of the data, we also allow for the treatment effect to vary over observed travel characteristics. Our empirical results suggest that fares and crowding are the key determinants of commuter responsiveness to the EBD policy

Major complication after intrauterine vesico-amniotic shunting

Bilateral foetal uropathy is the leading cause of chronic renal failure in childhood. Vesico-amniotic shunting (VAS) is a simple, feasible, and widely used procedure for decompressing the foetal urinary system. We report acase of a boy with bilateral foetal uropathy who underwent VAS at a gestational age of 29 weeks. Vesico-abdominal shunt dislodgement occurred and led to urinary ascites and anhydramnios. Postpartal laparotomy showed ashunt perforation between the urinary bladder and the peritoneal cavity

Identification of protein oligomerization states by analysis of interface conservation

The discrimination of true oligomeric protein–protein contacts from nonspecific crystal contacts remains problematic. Criteria that have been used previously base the assignment of oligomeric state on consideration of the area of the interface and/or the results of scoring functions based on statistical potentials. Both techniques have a high success rate but fail in more than 10% of cases. More importantly, the oligomeric states of several proteins are incorrectly assigned by both methods. Here we test the hypothesis that true oligomeric contacts should be identifiable on the basis of an increased degree of conservation of the residues involved in the interface. By quantifying the degree of conservation of the interface and comparing it with that of the remainder of the protein surface, we develop a new criterion that provides a highly effective complement to existing methods

Surgical risk factors in primary surgery for localized neuroblastoma: The LNESG1 study of the European International Society of Pediatric Oncology Neuroblastoma Group

PURPOSE: Although tumor resection is the mainstay of treatment for localized neuroblastoma, there are no established guidelines indicating which patients should be operated on immediately and which should undergo surgery after tumor reduction with chemotherapy. In an effort to develop such guidelines, the LNESG1 study defined surgical risk factors (SRFs) based on the imaging characteristics. PATIENTS AND METHODS: A total of 905 patients with suspected localized neuroblastoma were registered by 10 European countries between January 1995 and October 1999; 811 of 905 patients were eligible for this analysis. RESULTS: Information on SRFs was obtained for 719 of 811 patients; 367 without and 352 with SRFs. Of these 719 patients, 201 patients (four without and 197 with SRFs) underwent biopsy only. An attempt at tumor excision was made in 518 patients: 363 of 367 patients without and 155 of 352 patients with SRFs (98.9% v 44.0%). Complete excision was achieved in 271 of 363 patients without and in 72 of 155 patients with SRF (74.6% v 46.4%), near-complete excision was achieved in 81 and 61 patients (22.3% v 39.3%), and incomplete excision was achieved in 11 and 22 patients (3.0% v 14.2%), respectively. There were two surgery-related deaths. Nonfatal surgery-related complications occurred in 45 of 518 patients (8.7%) and were less frequent in patients without SRFs (5.0% v 17.4%). Associated surgical procedures were also less frequent in patients without SRFs (1.6% v 9.7%). CONCLUSION: The adoption of SRFs as predictors of adverse surgical outcome was validated because their presence was associated with lower complete resection rate and greater risk of surgery-related complications. Additional studies aiming to better define the surgical approach to localized neuroblastoma are warranted