44 research outputs found
Reducing Aggressive Responses to TCAS: Evaluation of a TCAS Training Program
The Traffic alert and Collision Avoidance System (TCAS) is an aircraft collision avoidance system designed to prevent mid-air collisions. While responding to a TCAS advisory is generally the safe course of action, instances of overly aggressive responses have resulted in injuries to crew members and passengers as well as disruptions in air traffic operations. However, current training standards do not address the need to mitigate overly aggressive responses. This paper details the design and evaluation of a training program for TCAS which incorporated a learning objective related to mitigating aggressive responses to advisories. The impact of the training program was evaluated by comparing the results of two flight simulator experiments. These experiments examined “trained” and “untrained” pilot responses to TCAS advisories in an integrated flight deck-Air Traffic Control simulator. Overall, the training program had a significant impact on the pilots’ behavior and aggressive responses to TCAS advisories were decreased
Transplantul hepatic ortotopic de la donator decedat la adult. Experienţa Centrului de Chirurgie Generală şi transplant hepatic Fundeni
Studiul de faţă analizează experienţa Centrului de Chirurgie Generală şi Transplant Hepatic din Institutul Clinic Fundeni în transplantul hepatic ortotopic cu ficat întreg de la donator decedat la adult (THO), din aprilie 2000 până în aprilie 2006. În această perioadă au fost realizate 45 de THO – 20 femei şi 25 de bărbaţi, cu vârste cuprinse între 19-57 de ani (medie de 45 ani).Indicaţiile pentru transplantare au fost: ciroză VHB – 11, ciroză VHB VHD – 6, ciroză VHC – 13 (2 cu hepatocarcinom), ciroză VHB VHC – 2, ciroză VHB VHD etanol – 1, ciroză biliară primitivă – 5, boala Wilson – 2, ciroză toxic-nutriţională – 2, ciroza toxică non-alcoolică – 1, ciroză autoimună – 1, colangită sclerogenă primitivă – 1. Cu trei excepţii, la care s-a folosit tehnica clasică de transplantare, ficatul a fost grefat după tehnica Belghiti. Complicaţiile postoperatorii locale au survenit la 19 bolnavi (42,22%), iar generale la 19 (42,22%); complicaţiile tardive au fost înregistrate la 20 pacienţi (44,44%), iar recidiva bolii la 7 pacienţi (15,55%). Mortalitatea intraoperatorie şi
postoperatorie imediată a fost de 6,66% (3 din 45 pacienţi). La peste 30 de zile de la TH, au decedat alţi cinci pacienţi (11,11%). Patru pacienţi (8,88%) au decedat la distanţă de momentul transplantului prin boală venoocluzivă, prin cancer bronho-pulmonar şi prin infarct miocardic -2. Patruzeci si doi de pacienţi au supravieţuit perioadei postoperatorii (93,33%) şi 33 peste un an (73,33%). THO reprezintă metoda principală de transplantare hepatică, cu o morbiditate şi mortalitate acceptabile
Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial
Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials.
Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure.
Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen.
Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049
A new class of glycomimetic drugs to prevent free fatty acid-induced endothelial dysfunction
Background: Carbohydrates play a major role in cell signaling in many biological processes. We have developed a set of glycomimetic drugs that mimic the structure of carbohydrates and represent a novel source of therapeutics for endothelial dysfunction, a key initiating factor in cardiovascular complications. Purpose: Our objective was to determine the protective effects of small molecule glycomimetics against free fatty acidinduced endothelial dysfunction, focusing on nitric oxide (NO) and oxidative stress pathways. Methods: Four glycomimetics were synthesized by the stepwise transformation of 2,5dihydroxybenzoic acid to a range of 2,5substituted benzoic acid derivatives, incorporating the key sulfate groups to mimic the interactions of heparan sulfate. Endothelial function was assessed using acetylcholineinduced, endotheliumdependent relaxation in mouse thoracic aortic rings using wire myography. Human umbilical vein endothelial cell (HUVEC) behavior was evaluated in the presence or absence of the free fatty acid, palmitate, with or without glycomimetics (1µM). DAF2 and H2DCFDA assays were used to determine nitric oxide (NO) and reactive oxygen species (ROS) production, respectively. Lipid peroxidation colorimetric and antioxidant enzyme activity assays were also carried out. RTPCR and western blotting were utilized to measure Akt, eNOS, Nrf2, NQO1 and HO1 expression. Results: Ex vivo endotheliumdependent relaxation was significantly improved by the glycomimetics under palmitateinduced oxidative stress. In vitro studies showed that the glycomimetics protected HUVECs against the palmitateinduced oxidative stress and enhanced NO production. We demonstrate that the protective effects of preincubation with glycomimetics occurred via upregulation of Akt/eNOS signaling, activation of the Nrf2/ARE pathway, and suppression of ROSinduced lipid peroxidation. Conclusion: We have developed a novel set of small molecule glycomimetics that protect against free fatty acidinduced endothelial dysfunction and thus, represent a new category of therapeutic drugs to target endothelial damage, the first line of defense against cardiovascular disease
Airspace analysis and design by data aggregation and lean model synthesis
Air traffic demand is growing. New methods of airspace design are required that can enable new designs, do not depend on current operations, and can also support quantifiable performance goals. The main goal of this thesis is to develop methods to model inherent safety and control cost so that these can be included as principal objectives of airspace design, in support of prior work which examines capacity. The first contribution of the thesis is to demonstrate two applications of airspace analysis and design: assessing the inherent safety and control cost of the airspace. Two results are shown, a model which estimates control cost depending on autonomy allocation and traffic volume, and the characterization of inherent safety conditions which prevent unsafe trajectories. The effects of autonomy ratio and traffic volume on control cost emerge from a Monte Carlo simulation of air traffic in an airspace sector. A maximum likelihood estimation identifies the Poisson process to be the best stochastic model for control cost. Recommendations are made to support control-cost-centered airspace design. A novel method to reliably generate collision avoidance advisories, in piloted simulations, by the widely-used Traffic Alert and Collision Avoidance System (TCAS) is used to construct unsafe trajectory clusters. Results show that the inherent safety of routes can be characterized, determined, and predicted by relatively simple convex polyhedra (albeit multi-dimensional and involving spatial and kinematic information). Results also provide direct trade-off relations between spatial and kinematic constraints on route geometries that preserve safety. Accounting for these clusters thus supports safety-centered airspace design. The second contribution of the thesis is a general methodology that generalizes unifying principles from these two demonstrations. The proposed methodology has three steps: aggregate data, synthesize lean model, and guide design. The use of lean models is a result of a natural flowdown from the airspace view to the requirements. The scope of the lean model is situated at a level of granularity that identifies the macroscopic effects of operational changes on the strategic level. The lean model technique maps low-level changes to high-level properties and provides predictive results. The use of lean models allows the mapping of design variables (route geometry, autonomy allocation) to design evaluation metrics (inherent safety, control cost).Ph.D
Control Cost Simulation Data
The main publications explaining the use of the simulation are:
Popescu, V.M., Airspace analysis and design by data aggregation and lean model synthesis, PhD thesis, Georgia Institute of Technology, 2013;
Popescu, V.M., Clarke, J.P.B., and Feigh, K.M., "A Comparison of Required Taskload in Simulated Autonomous and Controlled Airspace", Journal of Aerospace Information Systems, under review.Input data is extracted from historical traffic patterns. Information can be found in two papers: Gariel, M., Srivastava, A. N., and Feron, E., "Trajectory clustering and an application to airspace monitoring," IEEE Transactions on Intelligent Transportation Systems, vol. 12, no. 4, pp. 1511-1524, 2011.
Marzuoli, A., Gariel, M., Vela, A. E., and Feron, E., Air traffic optimization on a data-based network flow model," in 30th Digital Avionics Systems Conference, 2011.This simulation builds upon an optimization engine detailed in: Vela, A., Feigh, K. M., Solak, S., Singhose, W., and Clarke, J.-P., Formulation of reduced-taskload optimization models for conflict resolution," IEEE Transactions on Systems, Man and Cybernetics - Part A, vol. 42, no. 6, 2012.This simulation was used in the dissertation "Airspace analysis and design by data aggregation and lean model synthesis," which is available in SMARTech at http://hdl.handle.net/1853/49126. The files comprising the simulation are packaged in a zipped file, and they must be extracted before they can be used. Matlab software is required to run this simulation.This simulation studies control cost in an airspace sector. The effects of autonomy ratio and traffic volume on control cost are exhibited. The research uses a Monte Carlo simulator framework which allocates directly controlled routes and autonomous self-deconflicting 4-D trajectory flows in the airspace. Several stochastic models of aircraft scheduling, navigation precision, and conflict detection and resolution are interconnected in the simulation. A Poisson process model is proposed for control cost
Distributed spectrum sensing for indoor broadcasting services using an IoT platform
The switch to digital broadcasting technologies has allowed broadcasters an advanced level of personalization and interactivity. The possibility to deliver commercial content to more devices into the same domestic environment, excites both consumers and broadcasting service providers but is hindered by the lack of available RF spectrum. In this context, TV White Spaces (TVWS) are an ideal candidate for deploying interactive indoor broadcasting services, based on firm rules to avoid service disruption for broadcasters, by using joint spectrum sensing techniques. This paper proposes a distributed spectrum sensing method based on an IoT architecture. The architecture comes in support for short-range video broadcasting for delivering commercial contents to several TV devices in an indoor scenario, involving several sensing-enabled objects in a joint manner
Raport asupra activităţii şantierului Histria în campania 1956 / Rapport sur l’activité du chantier d’Histria en 1956
Pippidi Dionisie M., Eftimie Victoria, Stoian Iorgu, Popescu Emilian, Dimitriu Suzana, Coja Maria, Zirra Vlad, Alexandrescu Petre, Berciu Dumitru, Preda Constantin. Raport asupra activităţii şantierului Histria în campania 1956 / Rapport sur l’activité du chantier d’Histria en 1956. In: Materiale şi cercetări arheologice, N°5 1959. pp. 283-328
Şantierul Histria / Le chantier d’Histria
Condurachi Emil, Pippidi Dionisie M., Bordenache Gabriella, Eftimie Victoria, Stoian Iorgu, Popescu Emilian, Dimitriu Suzana, Radu Carmen, Coja Maria, Alexandrescu Petre, Zirra Vlad. Şantierul Histria / Le chantier d’Histria. In: Materiale şi cercetări arheologice, N°6 1959. pp. 265-306