CAPTCHaStar! A novel CAPTCHA based on interactive shape discovery

Over the last years, most websites on which users can register (e.g., email providers and social networks) adopted CAPTCHAs (Completely Automated Public Turing test to tell Computers and Humans Apart) as a countermeasure against automated attacks. The battle of wits between designers and attackers of CAPTCHAs led to current ones being annoying and hard to solve for users, while still being vulnerable to automated attacks. In this paper, we propose CAPTCHaStar, a new image-based CAPTCHA that relies on user interaction. This novel CAPTCHA leverages the innate human ability to recognize shapes in a confused environment. We assess the effectiveness of our proposal for the two key aspects for CAPTCHAs, i.e., usability, and resiliency to automated attacks. In particular, we evaluated the usability, carrying out a thorough user study, and we tested the resiliency of our proposal against several types of automated attacks: traditional ones; designed ad-hoc for our proposal; and based on machine learning. Compared to the state of the art, our proposal is more user friendly (e.g., only some 35% of the users prefer current solutions, such as text-based CAPTCHAs) and more resilient to automated attacks.Comment: 15 page

Electronic Origin of High Temperature Superconductivity in Single-Layer FeSe Superconductor

The latest discovery of high temperature superconductivity signature in single-layer FeSe is significant because it is possible to break the superconducting critical temperature ceiling (maximum Tc~55 K) that has been stagnant since the discovery of Fe-based superconductivity in 2008. It also blows the superconductivity community by surprise because such a high Tc is unexpected in FeSe system with the bulk FeSe exhibiting a Tc at only 8 K at ambient pressure which can be enhanced to 38 K under high pressure. The Tc is still unusually high even considering the newly-discovered intercalated FeSe system A_xFe_{2-y}Se_2 (A=K, Cs, Rb and Tl) with a Tc at 32 K at ambient pressure and possible Tc near 48 K under high pressure. Particularly interesting is that such a high temperature superconductivity occurs in a single-layer FeSe system that is considered as a key building block of the Fe-based superconductors. Understanding the origin of high temperature superconductivity in such a strictly two-dimensional FeSe system is crucial to understanding the superconductivity mechanism in Fe-based superconductors in particular, and providing key insights on how to achieve high temperature superconductivity in general. Here we report distinct electronic structure associated with the single-layer FeSe superconductor. Its Fermi surface topology is different from other Fe-based superconductors; it consists only of electron pockets near the zone corner without indication of any Fermi surface around the zone center. Our observation of large and nearly isotropic superconducting gap in this strictly two-dimensional system rules out existence of node in the superconducting gap. These results have provided an unambiguous case that such a unique electronic structure is favorable for realizing high temperature superconductivity

Development and use of a computer program to detect potentially inappropriate prescribing in older adults residing in Canadian long-term care facilities

BACKGROUND: Inappropriate prescribing has been estimated to be as high as 40% in long-term care. The purpose of this study was to develop a computer program that identifies potentially inappropriate drug prescriptions and to test its reliability. METHODS: Potentially inappropriate prescriptions were identified based on modified McLeod guidelines. A database from one pharmacy servicing long-term care facilities in Ontario was utilized for this cross-sectional study. Prescription information was available for the 356 long-term care residents and included: the date the prescription was filled, the quantity of drug prescribed and the eight-digit drug identification number. The pharmacy database was linked to the computer-based program for targeting potential inappropriate prescriptions. The computer program's reliability was assessed by comparing its results to a manual search conducted by two independent research assistants. RESULTS: There was complete agreement between the computer and manual abstraction for the total number of potentially inappropriate prescriptions detected. In total, 83 potentially inappropriate prescriptions were identified. Fifty-three residents (14.9%) received at least one potentially inappropriate prescription. Of those, twenty (37.7%) received two potential inappropriate prescriptions and eight (15.1%) received 3 or more potential inappropriate prescriptions. The most common potential inappropriate prescriptions were identified as long-term use of non-steroidal anti-inflammatory agents and tricyclic antidepressants with active metabolites. CONCLUSION: A computer program can accurately and automatically detect inappropriate prescribing in residents of long-term care facilities. This tool may be used to identify potentially inappropriate drug combinations and educate health care professionals

Case report of right hamate hook fracture in a patient with previous fracture history of left hamate hook: is it hamate bipartite?

BACKGROUND: Hamate hook fracture is a common fracture in golfers and others who play sports that involve rackets or sticks such as tennis or hockey. This patient had a previous hamate fracture in the opposing wrist along with potential features of hamate bipartite. CASE PRESENTATION: A 19 year old male presented with a complaint of right wrist pain on the ulnar side of the wrist with no apparent mechanism of injury. The pain came on gradually one week before being seen in the office and he reported no prior care for the complaint. His history includes traumatic left hamate hook fracture with surgical excision. CONCLUSION: The patient was found to have marked tenderness over the hamate and with a prior fracture to the other wrist, computed tomography of the wrist was ordered revealing a fracture to the hamate hook in the right wrist. He was referred for surgical evaluation and the hook of the hamate was excised. Post-surgically, the patient was able to return to normal activity within eight weeks. This case is indicative of fracture rather than hamate bipartite. This fracture should be considered in a case of ulnar sided wrist pain where marked tenderness is noted over the hamate, especially after participation in club or racket sports

Factor structure of the Shoulder Pain and Disability Index in patients with adhesive capsulitis

<p>Abstract</p> <p>Background</p> <p>The Shoulder Pain and Disability Index (SPADI) is a self-administered questionnaire that aims to measure pain and disability associated with shoulder disease. It consists of a pain section and a disability section with 13 items being responded to on visual analogue scales. Few researchers have investigated SPADI validity in specified diagnostic groups, although the selection of an evaluative instrument should be based on evidence of validity in the target patient group. The aim of the present study was to investigate factor structure of the SPADI in a study population of patients with adhesive capsulitis.</p> <p>Methods</p> <p>The questionnaire was administered to 191 patients with adhesive capsulitis. Descriptive statistics for items and a comparison of scores for the two subscales were produced. Internal consistency was analyzed by use of the Cronbach alpha and a principal components analysis with varimax rotation was conducted. Study design was cross-sectional.</p> <p>Results</p> <p>Two factors were extracted, but the factor structure failed to support the original division of items into separate pain and disability sections.</p> <p>Conclusion</p> <p>We found minimal evidence to justify the use of separate subscales for pain and disability. It is our impression that the SPADI should be viewed as essentially unidimensional in patients with adhesive capsulitis.</p

A novel method to analyze leukocyte rolling behavior in vivo

Leukocyte endothelial cell interaction is a fundamentally important process in many disease states. Current methods to analyze such interactions include the parallel-plate flow chamber and intravital microscopy. Here, we present an improvement of the traditional intravital microscopy that allows leukocyte-endothelial cell interaction to be studied from the time the leukocyte makes its initial contact with the endothelium until it adheres to or detaches from the endothelium. The leukocyte is tracked throughout the venular tree with the aid of a motorized stage and the rolling and adhesive behavior is measured off-line. Because this method can involve human error, methods to automate the tracking procedure have been developed. This novel tracking method allows for a more detailed examination of leukocyte-endothelial cell interactions

Constraints on Nucleon Decay via "Invisible" Modes from the Sudbury Neutrino Observatory

Data from the Sudbury Neutrino Observatory have been used to constrain the lifetime for nucleon decay to ``invisible'' modes, such as n -> 3 nu. The analysis was based on a search for gamma-rays from the de-excitation of the residual nucleus that would result from the disappearance of either a proton or neutron from O16. A limit of tau_inv > 2 x 10^{29} years is obtained at 90% confidence for either neutron or proton decay modes. This is about an order of magnitude more stringent than previous constraints on invisible proton decay modes and 400 times more stringent than similar neutron modes.Comment: Update includes missing efficiency factor (limits change by factor of 2) Submitted to Physical Review Letter

Osteoid osteoma of the femur in a 7-month-old infant treated with radiofrequency ablation

Osteoid osteoma occurs most commonly in children, adolescents, and young adults between the ages of 5 and 30 years. In the preschool age group, it is quite uncommon, accounting for only 3–8% of all osteoid osteoma cases. We report a case of osteoid osteoma in a 7-month-old infant, who presented with decreased use of the right lower extremity due to pain. Magnetic resonance imaging (MRI) showed an atypical appearance. A biopsy of the lesion, with histopathological examination, confirmed the diagnosis of osteoid osteoma. Radiofrequency ablation (RFA) of the nidus under computed tomography (CT) guidance was performed. The patient developed a recurrence after 3 months, which was treated with a second RFA. On subsequent follow-up, the infant did not show signs of pain after 1 month. In summary, this case report shows that osteoid osteoma can present in early infancy and can be successfully treated with RFA at this age, however, recurrence after the procedure can occur and close follow-up is recommended

The prognostic role of WHO classification, urinary 5-hydroxyindoleacetic acid and liver function tests in metastatic neuroendocrine carcinomas of the gastroenteropancreatic tract

The World Health Organisation (WHO) classification (2000) is widely used to classify neuroendocrine carcinomas (NECs), yet its prognostic value needs to be confirmed. In this study, patients with metastatic NECs (n=119) were classified according to WHO guidelines into well differentiated and poorly differentiated (WDNECs and PDNECs). Histological differentiation based on WHO criteria had the highest impact on overall survival (OS) (PDNECs : WDNECs hazard ratio (HR)=4.02, P=0.02); however, PDNECs represented only a small percentage of patients (8%). In a WDNEC-restricted analysis, abnormal liver function tests (LFTs) and elevated urinary 5-hydroxyindoleacetic acid (u5HIAA) were independent prognostic factors for survival (HR=2.65, P=0.006 and HR=2.51, P=0.003, respectively) and were used to create a WDNEC-specific prognostic model (low risk=both normal, intermediate risk=one of them abnormal, high risk=both abnormal). Low-risk WDNECs had the most favourable prognosis (median OS, mOS 8.1 years), which was significantly better compared to both intermediate-risk and high-risk WDNECs (mOS 3.2 and 1.4 years, with P=0.01 and P<0.001, respectively). High-risk WDNECs displayed the shortest OS (1.3 years), which was similar to that of PDNECs (P=0.572). This analysis supports the prognostic value of WHO classification for metastatic NECs arising from the gastroenteropancreatic tract; however, risk stratification using readily available u5HIAA and LFTs may be necessary for the heterogeneous group of WDNECs

First Neutrino Observations from the Sudbury Neutrino Observatory

The first neutrino observations from the Sudbury Neutrino Observatory are presented from preliminary analyses. Based on energy, direction and location, the data in the region of interest appear to be dominated by 8B solar neutrinos, detected by the charged current reaction on deuterium and elastic scattering from electrons, with very little background. Measurements of radioactive backgrounds indicate that the measurement of all active neutrino types via the neutral current reaction on deuterium will be possible with small systematic uncertainties. Quantitative results for the fluxes observed with these reactions will be provided when further calibrations have been completed.Comment: Latex, 7 pages, 10 figures, Invited paper at Neutrino 2000 Conference, Sudbury, Canada, June 16-21, 2000 to be published in the Proceeding