Nonlinear Control of Tunneling Through an Epsilon-Near-Zero Channel

The epsilon-near-zero (ENZ) tunneling phenomenon allows full transmission of waves through a narrow channel even in the presence of a strong geometric mismatch. Here we experimentally demonstrate nonlinear control of the ENZ tunneling by an external field, as well as self-modulation of the transmission resonance due to the incident wave. Using a waveguide section near cut-off frequency as the ENZ system, we introduce a diode with tunable and nonlinear capacitance to demonstrate both of these effects. Our results confirm earlier theoretical ideas on using an ENZ channel for dielectric sensing, and their potential applications for tunable slow-light structures

Development and Evaluation of an Electronic Vertical Situation Display

Current advanced commercial transport aircraft, such as the Boeing B777/B747-400, the Airbus A320/A340 and the McDonnell Douglas MD-11, rely on AutoFlight Systems (AFS) for flight management, navigation and inner loop control. These systems have evolved from straightforward autopilots into multiple computers capable of sophisticated and interrelated tasks. These tasks span the range from high level flight management to low level inner loop control. In addition, these systems provide envelope protection to prevent pilots from committing mistakes such as stalling the aircraft or lowering flaps at high speeds. Unfortunately, as these systems have become more complex and interconnected, a new class of problems has developed associated with pilots’ interaction with the automation. Many incidents have been reported where there exists some confusion between the pilots’ expectations of the AFS and what the system is actually doing (Corwin, 1995). This confusion has been termed a Mode Awareness Problem (MAP). After a description of the AFS, a formal definition of mode awareness problems is presented in Section 1.3 followed by representative incidents in which mode awareness problems are suspected as being a contributory factor

In vitro biomechanical comparison of various implants in Pauwels type 3 fracture neck femur

Background: The objective of this study was to find out the correlation among type of implant, type of fracture and quality of bone in a cadaveric model of unstable fracture neck of femur (Pauwels type 3) fixed with either; proximal femoral nail (PFN), dynamic hip screw (DHS), dynamic hip screw with an anti-rotation screw (DHS and ARS) or cannulated cancellous screws (CCS).Methods: This study was conducted on 24 cadaveric bones (6 in each group) in which unstable fracture neck of femur (Pauwels type 3) were created and fractures in each group were fixed with different implants after creating a comparable group using DEXA scan. These were tested on a cyclic physiological loading machine at 2 cycles per second with a load of 200kg. The test was observed for 10,000 loading cycles or till failure whichever occurred earlier. Subsidence was measured and analyzed.Results: Five specimens in the PFN group, 3 specimens in the DHS and ARS and DHS group completed 10,000 cycles while all the specimens in CCS group failed before 10000 cycles. Mean subsidence of the PFN group was significantly lower than the other groups.Conclusions: PFN constructs were stronger than the other constructs. However, these data must be interpreted as strictly biomechanical, representing only part of the scenario at work in vivo. Nonetheless, the significant findings of increased strength of fixation over the DHS, DHS with ARS and CCS certainly appear to support the use of PFN clinically.

Comparison of 0.5% Bupivacaine and 0.5% Ropivacaine epidurally in lower limb orthopaedic surgeries

Background: Ropivacaine in equi-potent concentrations with bupivacaine, the degree of motor blockade is less pronounced with ropivacaine, and there is a greater propensity for blocking pain transmitting A-delta and C fibres rather than A-α motor fibres. It appears to have most of the blocking characteristics of bupivacaine. So we have undertaken the study to compare ropivacaine 0.5% (20ml) and bupivacaine 0.5% (20ml) for epidural anaesthesia in patients undergoing lower limb orthopaedic surgeries.Methods: This double-blind, randomized study involves 60 patients who were undergone orthopaedic surgery, having ASA-I or ASA-II physical status. Out of 60, 30 patients received 20 ml of 0.5% ropivacaine and 30 patients received 20 ml of 0.5% bupivacaine at the L3, 4 interspace. Parameters measured were the onset time, duration and spread of sensory block, the onset time, peak time, duration and degree of motor block, the quality of anaesthesia and the heart rate and blood pressure profile during block onset.Results: Epidurally, Ropivacaine in comparison to Bupivacaine provides quicker onset, early peak effect and prolonged duration of sensory block and shorter duration of motor block. Ropivacaine provides prolonged effective analgesia. It reduces requirement of rescue analgesics and related side effects.Conclusions: Ropivacaine 0.5% is safer and effective alternative to Bupivacaine in epidural anaesthesia and post operative pain relief

NeMo: Network Module identification in Cytoscape

© 2010 Rivera et al; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution Licens

Accuracy of impressions with different impression materials in angulated implants

Purpose: To evaluate the dimensional accuracy of the resultant (duplicative) casts made from two different impression materials (polyvinyl siloxane and polyether) in parallel and angulated implants.Materials and Methods: Three definitive master casts (control groups) were fabricated in dental stone with three implants, placed at equi-distance. In first group (control), all three implants were placed parallel to each other and perpendicular to the plane of the cast. In the second and third group (control), all three implants were placed at 10° and 15° angulation respectively to the long axis of the cast, tilting towards the centre. Impressions were made with polyvinyl siloxane and polyether impression materials in a special tray, using a open tray impression technique from the master casts. These impressions were poured to obtain test casts. Three reference distances were evaluated on each test cast by using a profile projector and compared with control groups to determine the effect of combined interaction of implant angulation and impression materials on the accuracy of implant resultant cast.Results: Statistical analysis revealed no significant difference in dimensional accuracy of the resultant casts made from two different impression materials (polyvinyl siloxane and polyether) by closed tray impression technique in parallel and angulated implants.Conclusion: On the basis of the results of this study, the use of both the impression materials i.e., polyether and polyvinyl siloxane impression is recommended for impression making in parallel as well as angulated implants.Key words: Angulated implants, implant impression, impression accuracy, impression materia

Analysis of complexity evolution management and human performance issues in commercial aircraft automation systems

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000.Includes bibliographical references (p. 181-187).Autoflight systems in the current generation of aircraft have been implicated in several recent incidents and accidents. A contributory aspect to these incidents may be the manner in which aircraft transition between differing behaviours or "modes." The current state of aircraft automation was investigated and the incremental development of the autoflight system was tracked through a set of aircraft to gain insight into how these systems developed. This process appears to have resulted in a system without a consistent global representation. In order to evaluate and examine autoflight systems, a "Hybrid Automation Representation" was developed. This representation was used to examine several specific problems known to exist in aircraft systems. Cyclomatic complexity is an analysis tool from computer science which counts the number of linearly independent paths through a program graph. This approach was extended to examine autoflight mode transitions modelled with the Hybrid Automation Representation. A survey was conducted of pilots to identify those autoflight mode transitions which airline pilots find difficult. The transitions identified in this survey were analyzed using cyclomatic complexity to gain insight into the apparent complexity of the autoflight system from the perspective of the pilot. Mode transitions which had been identified as complex by pilots were found to have a high cyclomatic complexity. Further examination was made into a set of specific problems identified in aircraft: the lack of a consistent representation of automation, concern regarding appropriate feedback from the automation, and the implications of physical limitations on the autoflight systems. Mode transitions involved in changing to and leveling at a new altitude were identified across multiple aircraft by numerous pilots. Where possible, evaluation and verification of the behaviour of these autoflight mode transitions was investigated via aircraft-specific high fidelity simulators. Three solution approaches to concerns regarding autoflight systems, and mode transitions in particular, are presented in this thesis. The first is to use training to modify pilot behaviours, or procedures to work around known problems. The second approach is to mitigate problems by enhancing feedback. The third approach is to modify the process by which automation is designed. The Operator Directed Process forces the consideration and creation of an automation model early in the design process for use as the basis of the software specification and training.by Sanjay Sridhar Vakil.Ph.D

Development and evaluation of a prototype electronic vertical situation display

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1996.Includes bibliographical references (p. 103-104).by Sanjay S. Vakil.M.S

Analysis of Complexity Evolution Management and Human Performance Issues in Commercial Aircraft Automation Systems

Autoflight systems in the current generation of aircraft have been implicated in several recent incidents and accidents. A contributory aspect to these incidents may be the manner in which aircraft transition between differing behaviours or “modes.” The current state of aircraft automation was investigated and the incremental development of the autoflight system was tracked through a set of aircraft to gain insight into how these systems developed. This process appears to have resulted in a system without a consistent global representation.National Aeronautics and Space Administration under grants NAG1-1581 and NAG-1-1857. Support was also provided by FAA and NASA Grant FAA-95-G-017

Acceptability of HIV Rapid Testing in Diverse Clinical Settings in Iran

Introduction: Rapid HIV testing in clinical settings can identify previously undiagnosed persons and link them to care, as well provide patients with knowledge of their serostatus and risk reduction counseling. We conducted a survey to characterize factors affecting the acceptance or declining of rapid HIV testing among Iranian patients.Methods: This cross-sectional survey was conducted from October 2014 to December 2014 with patients in three different health care centers (an emergency department in an urban hospital, a rural health centre, a voluntary counseling and testing centre (VCT) within Imam Khomeini Hospital, Tehran, Iran and a rural health centre). Participants completed a semi-structured face-to-face questionnaire and were tested by an HIV rapid test (Chembio Sure Check).Results: Of 222 participants, 25 participants were from the urban emergency department, 40 from the urban VCT program, and 157 from the rural health care centre. All did the rapid HIV test; all were HIV negative. HIV-related risk profiles found the urban emergency department patients more likely to have multiple partners (26%, P<0.01) and history of sexually transmitted diseases (27%, P<0.001) compared to VCT patients (9% and 3%, respectively) and rural clinic patients (4% and 1%, respectively). Emergency department patients were also more willing to pay for a HIV rapid test (44%, P<0.01), doing a rapid self-test at home (84%,P=0.01), preferring pharmacies as a place for providing rapid tests (80%, P=0.001). Also level of participants’ awareness was considerably different between mentioned centres (median=11, 12, 10 for emergency department, VCT and rural Health care centre respectively; P=0.012).Conclusions: Increasing knowledge about HIV rapid testing, its availability, and keeping costs low can expand the desire to use the test and ultimately prevent the spread of HIV through lack of knowing one’s serostatus and lack of treatment. Emergency departments in urban Iran may be an opportunity to test persons at high risk for HIV infection