Signature of pseudo-diffusive transport in mesoscopic topological insulators

One of the unique features of Dirac Fermions is pseudo-diffusive transport by evanescent modes at low Fermi energies when the disorder is low. At higher Fermi energies i.e. carrier densities, the electrical transport is diffusive in nature and the propagation occurs via plane-waves. In this study, we report the detection of such evanescent modes in the surface states of topological insulator through 1/f noise. While signatures of pseudo-diffusive transport have been seen experimentally in graphene, such behavior is yet to be observed explicitly in any other system with a Dirac dispersion. To probe this, we have studied 1/f noise in topological insulators as a function of gate-voltage, and temperature. Our results show a non-monotonic behavior in 1=f noise as the Fermi energy is varied, suggesting a crossover from pseudo-diffusive to diffusive transport regime in mesoscopic topological insulators. The temperature dependence of noise points towards conductance fluctuations from quantum interference as the dominant source of the noise in these samples.Comment: 5 pages, 4 figure

Group-Key Management Model for Worldwide Wireless Mesh Networks

Wireless Mesh Network (WMN) is an upcoming wireless network technology and is mainly used to provide broadband internet in remote locations. It is characterized by minimum fixed infrastructure requirement and is operated in an open medium, such that any user within the range covered by mesh routers may access the network. So a critical requirement for the security in WMN is the authentication of users. However, WMN is far from mature for large-scale deployment in some applications due to the lack of the satisfactory guarantees on security. A wellperformed security framework for WMN will contribute to network survivability and strongly support the network growth or reduction. A key management model to overcome the scalability issue on security aspect for large-scale deployment of WMN i.e. Worldwide WMN is proposed in this work, which aims to guarantee wellperformed key management services and protection from potential attacks. Here, we use a combination of techniques, such as zonebased topology structure, off-line CA, virtual certification authority ) etc

Using Hyperlocal Delivery System to Accelerate Localised Business

Hyperlocal organizations provide purchasers with merchandise delivery and utility administrations. Merchandise delivery includes staple goods, food, prescriptions, and personal needs, while utility administrations include plumbing, home cleaning, yard care, electrical, and drainage. Each of these services and products is provided by an organization of individuals from businesses or neighborhoods. Hyperlocal administration stages enable eateries, lodging, discount food outlets, organic products or vegetables, fish, and meat, and other retailers to attract and manage customers effectively without worrying about shipment. Simple web connectivity and the proliferation of cell phones have significantly increased interest in hyperlocal administrations. Occupied way of life accelerates the growth of the online food and staples ordering market, which in turn accelerates the growth of hyperlocal services in the emerging online market

Low temperature saturation of phase coherence length in topological insulators

Implementing topological insulators as elementary units in quantum technologies requires a comprehensive understanding of the dephasing mechanisms governing the surface carriers in these materials, which impose a practical limit to the applicability of these materials in such technologies requiring phase coherent transport. To investigate this, we have performed magneto-resistance (MR) and conductance fluctuations\ (CF) measurements in both exfoliated and molecular beam epitaxy grown samples. The phase breaking length ($l_{\phi}$) obtained from MR shows a saturation below sample dependent characteristic temperatures, consistent with that obtained from CF measurements. We have systematically eliminated several factors that may lead to such behavior of $l_{\phi}$ in the context of TIs, such as finite size effect, thermalization, spin-orbit coupling length, spin-flip scattering, and surface-bulk coupling. Our work indicates the need to identify an alternative source of dephasing that dominates at low $T$ in topological insulators, causing saturation in the phase breaking length and time

Effect of Chronic Illnesses on Length of Stay and Mortality of Community Acquired Pneumonia in a Community Hospital

The aim of this study was to determine the effect of demographics, substance abuse, and chronic illnesses on length of hospitalization and mortality of pneumonia. 866 patients admitted to a community hospital with diagnosis of community-acquired pneumonia were studied. Linear and logistic regression analyses were performed for the effect of chronic illnesses on length of stay and mortality. Age (p=0.064), coronary artery disease (p=0.017), congestive heart failure (p=0.011), history of neoplasm (p=0.079) and chronic kidney disease (p[less than]0.001) were associated with increased length of stay. Age (p[less than]0.001), history of stroke (p=0.013), history of neoplasm (p=0.028), and chronic kidney disease (p=0.005) were associated with higher mortality from community-acquired pneumonia. Asthma was associated with decreased length of stay (p=0.006) but no difference in mortality. Respiratory failure and congestive heart failure exacerbation were associated with longer length of stay (p[less than]0.001) but no difference in mortality. ICU admission was associated with longer hospital stay and higher mortality (p[less than]0.001). Septic shock secondary to pneumonia was associated with longer length of stay and higher mortality (p[less than]0.0001). Age (p=0.04), alcohol abuse (p=0.03), coronary artery disease (p=0.05), congestive heart failure (p=0.009) and chronic kidney disease (p=0.011) were predictors of higher level of care needed during hospital stay for community acquired pneumonia.Saurabh Dwivedi (1), Rajni Madaan (1), Saurav Pokharel (2), Bikash Bhattarai (3), Abhishek Sinha Ray (4), Meenakshi Ghosh (4) ; 1. Internal Medicine, Latrobe Hospital, Excela Health. 2. Pulmonary Disease, Frye Regional Medical Center. 3. Pulmonary Disease, Amita Health. 4. Nephrology, Good Samaritan Hospital.Includes bibliographical reference

New Oral Anticoagulants are Not Superior to Warfarin in Secondary Prevention of Stroke or Transient Ischemic Attacks, but Lower the Risk of Intracranial Bleeding: Insights from a Meta-Analysis and Indirect Treatment Comparisons

PURPOSE: Patients with Atrial Fibrillation (AF) and prior stroke are classified as high risk in all risk stratification schemes. A systematic review and meta-analysis was performed to compare the efficacy and safety of New Oral Anticoagulants (NOACs) to warfarin in patients with AF and previous stroke or transient ischemic attack (TIA). METHODS: Three randomized controlled trials (RCTs), including total 14527 patients, comparing NOACs (apixaban, dabigatran and rivaroxaban) with warfarin were included in the analysis. Primary efficacy endpoint was ischemic stroke, and primary safety endpoint was intracranial bleeding. Random-effects models were used to pool efficacy and safety data across RCTs. RevMan and Stata software were used for direct and indirect comparisons, respectively. RESULTS: In patients with AF and previous stroke or TIA, effects of NOACs were not statistically different from that of warfarin, in reduction of stroke (Odds Ratio [OR] 0.86, 95% confidence interval [CI] 0.73- 1.01), disabling and fatal stroke (OR 0.85, 95% CI 0.71-1.04), and all-cause mortality (OR 0.90, 95% CI 0.79 -1.02). Randomization to NOACs was associated with a significantly lower risk of intracranial bleeding (OR 0.42, 95% CI 0.25-0.70). There were no major differences in efficacy between apixaban, dabigatran (110 mg BID and 150 mg BID) and rivaroxaban. Major bleeding was significantly lower with apixaban and dabigatran (110 mg BID) compared with dabigatran (150 mg BID) and rivaroxaban. CONCLUSION: NOACs may not be more effective than warfarin in the secondary prevention of ischemic stroke in patients with a prior history of cerebrovascular ischemia, but have a lower risk of intracranial bleeding

An efficient source localization method in presence of multipath using smart antenna system

In this paper, a MATLAB based smart antenna testbed that efficiently localizes the line-of-sight (LOS) source in the presence of multipath signals is developed. By exploiting the consistent amplitude nature of the LOS signal, a variant of Constant Modulus Algorithm, namely Multitarget-Least Square Constant Modulus Algorithm is employed to adapt and update the weights of the smart antenna for estimation of the direction-of-arrival (DOA) of the of the LOS and multipath interference signals. Performance is compared with the conventional and recently proposed algorithms in the same testbed with alike considerations. Simulation result shows that the proposed method of DOA estimation performs better in terms of probability of resolution and root mean square error