SAFIUS - A secure and accountable filesystem over untrusted storage

We describe SAFIUS, a secure accountable file system that resides over an untrusted storage. SAFIUS provides strong security guarantees like confidentiality, integrity, prevention from rollback attacks, and accountability. SAFIUS also enables read/write sharing of data and provides the standard UNIX-like interface for applications. To achieve accountability with good performance, it uses asynchronous signatures; to reduce the space required for storing these signatures, a novel signature pruning mechanism is used. SAFIUS has been implemented on a GNU/Linux based system modifying OpenGFS. Preliminary performance studies show that SAFIUS has a tolerable overhead for providing secure storage: while it has an overhead of about 50% of OpenGFS in data intensive workloads (due to the overhead of performing encryption/decryption in software), it is comparable (or better in some cases) to OpenGFS in metadata intensive workloads.Comment: 11pt, 12 pages, 16 figure

Understanding the role of social media in political corporate branding research in the context of Indian politics

This paper seeks to explore how political actors within the Bharatiya Janata Party (BJP) use social media in their communication campaigns and how these social media platforms are understood by citizens following the 2014 Indian General Election. This research attempts to address the limited understanding of social media in the context of politics (Barnard and Kreiss, 2013; Burton and Shea, 2010; Cogburn and Espinoza-Vasquez 2011; Ganz, 2009; Gulati and Williams, 2007; Kumar 2009; Owen and Davis 2008). Furthermore, the limited research on political branding and social media has predominantly focused a western context negating eastern perspectives including the republic of India. This study will use the adapted Kapferer’s (2008) brand identity prism developed by Pich et al. (2014) to a political setting. This framework will ground the study and offer the opportunity to examine the role of social media from an internal brand identity and external brand image perspective. The findings will have implications not only for political parties but also for politicians, candidates and other parties interested in social media. This study will offer organisations a mechanism that will allow them understand how their social media is projected and understood and allow them to investigate whether their projected brand identity is coherent with the understood external brand image

Clinical and Angiographic profile of patients with left main Coronary Artery Stenosis

INTRODUCTION: Left main coronary artery disease is an important risk factor for increased morbidity and mortality in the diagnosis and management of coronary artery disease. Left main coronary artery disease is a highly emergency and lethal condition characterised by high mortality if not intervened early. Left main disease is can be silent with unpredictable presentation, which poses diagnostic and management challenges. Left main coronary artery disease is seen in 7 to 15% of patients who are having coronary artery disease by coronary angiography. Overall incidence of significant obstructive left main disease is about 4% of all subjects undergoing coronary angiography. Multivessel disease of other coronary arteries are seen in 80% of patients with left main disease. With drug eluting stents and advances in percutaneous coronary intervention management of this disease is not purely surgical. In CASS registry patients with significant left main stenosis (stenosis of ≥ 50%) found to have mean survival of about 13.3 years in surgical group compared to 6.6 years in medical treatment group4. The survival benefit in CABG group was also seen patients who are asymptomatic. AIMS AND OBJECTIVES: 1. To study the risk factors associated with the development LMCA disease. 2. To study type of presentation to hospital in patients with LMCA disease. 3. To study clinical features of patients with left main stem disease. 4. To study angiographic characteristics of patients with LMCA disease. 5. To study the pattern of involvement in patients with various risk factors who present with LMCA disease. 6. To study the in hospital outcome of patients with left main disease diagnosed during coronary angiography. MATERIALS AND METHODS: We conducted the study in department of cardiology at Rajiv Gandhi Government General hospital in Chennai. Patients underwent coronary angiogram for usual indications which include emergency and elective. Emergency indications include patients admitted for acute coronary syndrome in coronary care unit and were taken for coronary angiogram for various indications. Elective indications include patients with chronic stable angina who were enrolled for coronary angiogram either directly or following a positive stress test. Patients who were excluded from this study were those with valvular heart disease, congenital heart disease, cardiomyopathy, who were taken up for coronary angiogram. All patients were routine evaluvated with standard blood tests before coronary angiogram include complete blood count, blood urea, serum creatinine, serum electrolytes, coagulation profile, electrocardiogram, chest X-Ray, Echocardiogram by PHILIPS HD 7 machine before the procedure. Coronary angiogram was performed by consultant cardiologists of our department in our cath lab by TOSHIBA infinix machine with standard views. Number of views were minimised if the patient found to have left main stem disease during the procedure. Quantitative coronary angiography was used to measure the diameter stenosis of coronary arteries. All patients with left main coronary artery disease either isolated or with other coronary artery involvement are included in this study. RESULTS: In our study we analysed about 400 coronary angiograms during the study period and found 36 cases with left main coronary artery disease which constitutes about 9% overall incidence in the population that undergone coronary angiogram. CONCLUSION: The overall incidence of left main coronary artery disease in patients undergoing coronary angiogram is about 9%. If only significant obstructive lesions are considered it is about 3%. Only one third of patients with left main disease is obstructive and rest are non obstructive. The majority of cases occurs between 50 to 60 years. Males outnumber the females when overall incidence is considered however if percentage of obstructive disease compared to nonobstructive disease female incidence is higher. All the risk factors are associated with left main disease with about two third cases were nonobstructive except in smokers were obstructive disease incidence is slightly high. Mode of presentation is commonly unstable angina, with stable angina is second common. Patients with obstructive left main disease has florid presentation in the form of high risk unstable angina, severe class stable angina , ST elevation myocardial infarction. Some patients with severe obstructive left main disease also present with heart failure and cardiogenic shock. ST elevation in avR is the common ECG change seen in patients with obstructive left main disease. Some patients with unstable angina and obstructive left main disease also had wall motion abnormalities, and reduced ejection fraction in echocardiogram. Distal left main disease especially bifurcation lesions are the commonest lesions in coronary angiogram in patients with left main disease. Two third of patients with distal left main disease had associated triple vessel disease

High Field Magneto-Conductivity Analysis of Bi2Se3 Single Crystal

We report the high field (up to 14Tesla) magneto-conductivity analysis of Bi2Se3 topological insulator grown via the self flux method. The detailed experimental investigations including crystal growth as well as the electrical, thermal and spectroscopic characterizations of the resultant Bi2Se3 single crystal are already reported by some of us. The current letter deals with high field magneto-conductivity analysis in terms of Hikami Larkin Nagaoka (HLN) model, which revealed that the electronic conduction is dominated by both surface states driven weak anti localization (WAL), as well the bulk WL (weak localization) states. Further, by applying the HLN equation we have extracted the fitting parameters i.e., phase coherence length and the pre-factor. The HLN equation exhibited values of [pre factor close to -1.0, indicating both WAL and WL contributions. On the other hand, the extracted phase coherence length is seen to decrease from 11.125 nm to 5.576 nm as the temperature is increased from 5K to 200K respectively. Summarily, the short letter discusses primarily the temperature dependent magneto-conductivity analysis of pristine Bi2Se3 single crystal by the HLN model.Comment: Letter to Editor MS: 10 pages including 3 Fig

Crystal Growth and Characterization of Bulk Sb2Te3Topological Insulator

The Sb2Te3 crystals are grown using the conventional self flux method via solid state reaction route, by melting constituent elements (Sb and Te) at high temperature (850 C), followed by slow cooling (2 C per hour).The weak anti localization (WAL) related low field (2 Tesla) magneto-conductance at low temperatures (2.5 K and 20 K) has been analysed and discussed using the Hikami- Larkin - Nagaoka (HLN) model. Summarily, the short letter reports an easy and versatile method for crystal growth of bulk Sb2Te3 topological insulator (TI) and its brief physical property characterization.Comment: 18 Pages Text + Figs: Accepted Mat. Res. Exp. (May 2018