Field Flight Dynamics of Hummingbirds during Territory Encroachment and Defense.

PubMed

Sholtis, Katherine M; Shelton, Ryan M; Hedrick, Tyson L

2015-01-01

Hummingbirds are known to defend food resources such as nectar sources from encroachment by competitors (including conspecifics). These competitive intraspecific interactions provide an opportunity to quantify the biomechanics of hummingbird flight performance during ecologically relevant natural behavior. We recorded the three-dimensional flight trajectories of Ruby-throated Hummingbirds defending, being chased from and freely departing from a feeder. These trajectories allowed us to compare natural flight performance to earlier laboratory measurements of maximum flight speed, aerodynamic force generation and power estimates. During field observation, hummingbirds rarely approached the maximal flight speeds previously reported from wind tunnel tests and never did so during level flight. However, the accelerations and rates of change in kinetic and potential energy we recorded indicate that these hummingbirds likely operated near the maximum of their flight force and metabolic power capabilities during these competitive interactions. Furthermore, although birds departing from the feeder while chased did so faster than freely-departing birds, these speed gains were accomplished by modulating kinetic and potential energy gains (or losses) rather than increasing overall power output, essentially trading altitude for speed during their evasive maneuver. Finally, the trajectories of defending birds were directed toward the position of the encroaching bird rather than the feeder.

Runway Safety Monitor Algorithm for Single and Crossing Runway Incursion Detection and Alerting

NASA Technical Reports Server (NTRS)

Green, David F., Jr.

2006-01-01

The Runway Safety Monitor (RSM) is an aircraft based algorithm for runway incursion detection and alerting that was developed in support of NASA's Runway Incursion Prevention System (RIPS) research conducted under the NASA Aviation Safety and Security Program's Synthetic Vision System project. The RSM algorithm provides warnings of runway incursions in sufficient time for pilots to take evasive action and avoid accidents during landings, takeoffs or when taxiing on the runway. The report documents the RSM software and describes in detail how RSM performs runway incursion detection and alerting functions for NASA RIPS. The report also describes the RIPS flight tests conducted at the Reno/Tahoe International Airport (RNO) and the Wallops Flight Facility (WAL) during July and August of 2004, and the RSM performance results and lessons learned from those flight tests.

Cooperative Collision Avoidance Step 1 - Technology Demonstration Flight Test Report. Revision 1

NASA Technical Reports Server (NTRS)

Trongale, Nicholas A.

2006-01-01

The National Aeronautics and Space Administration (NASA) Access 5 Project Office sponsored a cooperative collision avoidance flight demonstration program for unmanned aircraft systems (UAS). This flight test was accomplished between September 21st and September 27th 2005 from the Mojave Airport, Mojave, California. The objective of these flights was to collect data for the Access 5 Cooperative Collision Avoidance (CCA) Work Package simulation effort, i.e., to gather data under select conditions to allow validation of the CCA simulation. Subsequent simulation to be verified were: Demonstrate the ability to detect cooperative traffic and provide situational awareness to the ROA pilot; Demonstrate the ability to track the detected cooperative traffic and provide position information to the ROA pilot; Demonstrate the ability to determine collision potential with detected cooperative traffic and provide notification to the ROA pilot; Demonstrate that the CCA subsystem provides information in sufficient time for the ROA pilot to initiate an evasive maneuver to avoid collision; Demonstrate an evasive maneuver that avoids collision with the threat aircraft; and lastly, Demonstrate the ability to assess the adequacy of the maneuver and determine that the collision potential has been avoided. The Scaled Composites, LLC Proteus Optionally Piloted Vehicle (OPV) was chosen as the test platform. Proteus was manned by two on-board pilots but was also capable of being controlled from an Air Vehicle Control Station (AVCS) located on the ground. For this demonstration, Proteus was equipped with cooperative collision sensors and the required hardware and software to place the data on the downlink. Prior to the flight phase, a detailed set of flight test scenarios were developed to address the flight test objectives. Two cooperative collision avoidance sensors were utilized for detecting aircraft in the evaluation: Traffic Alert and Collision Avoidance System-II (TCAS-II) and Automatic Dependent Surveillance Broadcast (ADS-B). A single intruder aircraft was used during all the flight testing, a NASA Gulfstream III (G-III). During the course of the testing, six geometrically different near-collision scenarios were evaluated. These six scenarios were each tested using various combinations of sensors and collision avoidance software. Of the 54 planned test points 49 were accomplished successfully. Proteus flew a total of 21.5 hours during the testing and the G-III flew 19.8 hours. The testing fully achieved all flight test objectives. The Flight IPT performed an analysis to determine the accuracy of the simulation model used to predict the location of the host aircraft downstream during an avoidance maneuver. The data collected by this flight program was delivered to the Access 5 Cooperative Collision Avoidance (CCA) Work Package Team who was responsible for reporting on their analysis of this flight data.

Evasion of added isotopic mercury from a northern temperate lake

USGS Publications Warehouse

Southworth, G.; Lindberg, S.; Hintelmann, H.; Amyot, M.; Poulain, A.; Bogle, M.; Peterson, M.; Rudd, J.; Harris, R.; Sandilands, K.; Krabbenhoft, D.; Olsen, M.

2007-01-01

Isotopically enriched Hg (90% 202Hg) was added to a small lake in Ontario, Canada, at a rate equivalent to approximately threefold the annual direct atmospheric deposition rate that is typical of the northeastern United States. The Hg spike was thoroughly mixed into the epilimnion in nine separate events at two-week intervals throughout the summer growing season for three consecutive years. We measured concentrations of spike and ambient dissolved gaseous Hg (DGM) concentrations in surface water and the rate of volatilization of Hg from the lake on four separate, week-long sampling periods using floating dynamic flux chambers. The relationship between empirically measured rates of spike-Hg evasion were evaluated as functions of DGM concentration, wind velocity, and solar illumination. No individual environmental variable proved to be a strong predictor of the evasion flux. The DGM-normalized flux (expressed as the mass transfer coefficient, k) varied with wind velocity in a manner consistent with existing models of evasion of volatile solutes from natural waters but was higher than model estimates at low wind velocity. The empirical data were used to construct a description of evasion flux as a function of total dissolved Hg, wind, and solar illumination. That model was then applied to data for three summers for the experiment to generate estimates of Hg re-emission from the lake surface to the atmosphere. Based on ratios of spike Hg to ambient Hg in DGM and dissolved total Hg pools, ratios of DGM to total Hg in spike and ambient Hg pools, and flux estimates of spike and ambient Hg, we concluded that the added Hg spike was chemically indistinguishable from the ambient Hg in its behavior. Approximately 45% of Hg added to the lake over the summer was lost via volatilization. ?? 2007 SETAC.

Enhancing cancer immunotherapy using antiangiogenics: opportunities and challenges

PubMed Central

Fukumura, Dai; Kloepper, Jonas; Amoozgar, Zohreh; Duda, Dan G.; Jain, Rakesh K.

2018-01-01

Immunotherapy has emerged as a major therapeutic modality in oncology. Currently, however, the majority of patients with cancer do not derive benefit from these treatments. Vascular abnormalities are a hallmark of most solid tumours and facilitate immune evasion. These abnormalities stem from elevated levels of proangiogenic factors, such as VEGF and angiopoietin 2 (ANG2); judicious use of drugs targeting these molecules can improve therapeutic responsiveness, partially owing to normalization of the abnormal tumour vasculature that can, in turn, increase the infiltration of immune effector cells into tumours and convert the intrinsically immunosuppressive tumour microenvironment (TME) to an immunosupportive one. Immunotherapy relies on the accumulation and activity of immune effector cells within the TME, and immune responses and vascular normalization seem to be reciprocally regulated. Thus, combining antiangiogenic therapies and immunotherapies might increase the effectiveness of immunotherapy and diminish the risk of immune-related adverse effects. In this Perspective, we outline the roles of VEGF and ANG2 in tumour immune evasion and progression, and discuss the evidence indicating that antiangiogenic agents can normalize the TME. We also suggest ways that antiangiogenic agents can be combined with immune-checkpoint inhibitors to potentially improve patient outcomes, and highlight avenues of future research. PMID:29508855

Evasive mimicry: when (if ever) could mimicry based on difficulty of capture evolve?

PubMed

Ruxton, G D; Speed, M; Sherratt, T N

2004-10-22

We elucidate the conditions under which an easy-to-catch edible prey species may evolve to resemble another edible species that is much more difficult to capture ('evasive Batesian mimicry'), and the conditions under which two or more edible but hard-to-catch species evolve a common resemblance ('evasive Mullerian mimicry'). Using two complementary mathematical models, we argue that both phenomena are logically possible but that several factors will limit the prevalence of these forms of mimicry in nature. Evasive Batesian mimicry is most likely to arise when it is costly in time or energy for the predator species to pursue evasive prey, when mimics are encountered less frequently than evasive models and where there are abundant alternative prey. Evasive Mullerian mimicry, by contrast, is most likely to arise when evasive prey species differ in abundance, predators are slow to learn to avoid evasive prey and evading capture is costly to the prey. Unequivocal evidence for evasive Batesian or Mullerian mimicry has not yet been demonstrated in the field, and we argue that more empirical work is needed to test whether putative examples are indeed a result of selection to signal difficulty of capture.

31 CFR 585.214 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 585... Prohibitions § 585.214 Evasions; attempts; conspiracies. Any transaction for the purpose of, or which has the effect of, evading or avoiding, or which facilitates the evasion or avoidance of, any of the prohibitions...

31 CFR 597.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 597... REGULATIONS Prohibitions § 597.204 Evasions; attempts; conspiracies. Any transaction for the purpose of, or which has the effect of, evading or avoiding, or which facilitates the evasion or avoidance of, any of...

31 CFR 536.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 536... Prohibitions § 536.204 Evasions; attempts; conspiracies. Any transaction for the purpose of, or which has the effect of, evading or avoiding, or which facilitates the evasion or avoidance of, any of the prohibitions...

31 CFR 575.211 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 575... § 575.211 Evasions; attempts; conspiracies. Any transaction for the purpose of, or which has the effect of, evading or avoiding, or which facilitates the evasion or avoidance of, any of the prohibitions...

31 CFR 596.202 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 596... REGULATIONS Prohibitions § 596.202 Evasions; attempts; conspiracies. Any transaction for the purpose of, or which has the effect of, evading or avoiding, or which facilitates the evasion or avoidance of, any of...

ERAP1 overexpression in HPV-induced malignancies: A possible novel immune evasion mechanism.

PubMed

Steinbach, Alina; Winter, Jan; Reuschenbach, Miriam; Blatnik, Renata; Klevenz, Alexandra; Bertrand, Miriam; Hoppe, Stephanie; von Knebel Doeberitz, Magnus; Grabowska, Agnieszka K; Riemer, Angelika B

2017-01-01

Immune evasion of tumors poses a major challenge for immunotherapy. For human papillomavirus (HPV)-induced malignancies, multiple immune evasion mechanisms have been described, including altered expression of antigen processing machinery (APM) components. These changes can directly influence epitope presentation and thus T-cell responses against tumor cells. To date, the APM had not been studied systematically in a large array of HPV + tumor samples. Therefore in this study, systematic expression analysis of the APM was performed on the mRNA and protein level in a comprehensive collection of HPV16 + cell lines. Subsequently, HPV + cervical tissue samples were examined by immunohistochemistry. ERAP1 (endoplasmic reticulum aminopeptidase 1) was the only APM component consistently altered - namely overexpressed - in HPV16 + tumor cell lines. ERAP1 was also found to be overexpressed in cervical intraepithelial neoplasia and cervical cancer samples; expression levels were increasing with disease stage. On the functional level, the influence of ERAP1 expression levels on HPV16 E7-derived epitope presentation was investigated by mass spectrometry and in cytotoxicity assays with HPV16-specific T-cell lines. ERAP1 overexpression did not cause a complete destruction of any of the HPV epitopes analyzed, however, an influence of ERAP1 overexpression on the presentation levels of certain HPV epitopes could be demonstrated by HPV16-specific CD8 + T-cells. These showed enhanced killing toward HPV16 + CaSki cells whose ERAP1 expression had been attenuated to normal levels. ERAP1 overexpression may thus represent a novel immune evasion mechanism in HPV-induced malignancies, in cases when presentation of clinically relevant epitopes is reduced by overactivity of this peptidase.

Progranulin and its biological effects in cancer.

PubMed

Arechavaleta-Velasco, Fabian; Perez-Juarez, Carlos Eduardo; Gerton, George L; Diaz-Cueto, Laura

2017-11-07

Cancer cells have defects in regulatory mechanisms that usually control cell proliferation and homeostasis. Different cancer cells share crucial alterations in cell physiology, which lead to malignant growth. Tumorigenesis or tumor growth requires a series of events that include constant cell proliferation, promotion of metastasis and invasion, stimulation of angiogenesis, evasion of tumor suppressor factors, and avoidance of cell death pathways. All these events in tumor progression may be regulated by growth factors produced by normal or malignant cells. The growth factor progranulin has significant biological effects in different types of cancer. This protein is a regulator of tumorigenesis because it stimulates cell proliferation, migration, invasion, angiogenesis, malignant transformation, resistance to anticancer drugs, and immune evasion. This review focuses on the biological effects of progranulin in several cancer models and provides evidence that this growth factor should be considered as a potential biomarker and target in cancer treatment.

Analysis of Driver Evasive Maneuvering Prior to Intersection Crashes Using Event Data Recorders.

PubMed

Scanlon, John M; Kusano, Kristofer D; Gabler, Hampton C

2015-01-01

Intersection crashes account for over 4,500 fatalities in the United States each year. Intersection Advanced Driver Assistance Systems (I-ADAS) are emerging vehicle-based active safety systems that have the potential to help drivers safely navigate across intersections and prevent intersection crashes and injuries. The performance of an I-ADAS is expected to be highly dependent upon driver evasive maneuvering prior to an intersection crash. Little has been published, however, on the detailed evasive kinematics followed by drivers prior to real-world intersection crashes. The objective of this study was to characterize the frequency, timing, and kinematics of driver evasive maneuvers prior to intersection crashes. Event data recorders (EDRs) downloaded from vehicles involved in intersection crashes were investigated as part of NASS-CDS years 2001 to 2013. A total of 135 EDRs with precrash vehicle speed and braking application were downloaded to investigate evasive braking. A smaller subset of 59 EDRs that collected vehicle yaw rate was additionally analyzed to investigate evasive steering. Each vehicle was assigned to one of 3 precrash movement classifiers (traveling through the intersection, completely stopped, or rolling stop) based on the vehicle's calculated acceleration and observed velocity profile. To ensure that any significant steering input observed was an attempted evasive maneuver, the analysis excluded vehicles at intersections that were turning, driving on a curved road, or performing a lane change. Braking application at the last EDR-recorded time point was assumed to indicate evasive braking. A vehicle yaw rate greater than 4° per second was assumed to indicate an evasive steering maneuver. Drivers executed crash avoidance maneuvers in four-fifths of intersection crashes. A more detailed analysis of evasive braking frequency by precrash maneuver revealed that drivers performing complete or rolling stops (61.3%) braked less often than drivers traveling through the intersection without yielding (79.0%). After accounting for uncertainty in the timing of braking and steering data, the median evasive braking time was found to be between 0.5 to 1.5 s prior to impact, and the median initial evasive steering time was found to occur between 0.5 and 0.9 s prior to impact. The median average evasive braking deceleration for all cases was found to be 0.58 g. The median of the maximum evasive vehicle yaw rates was found to be 8.2° per second. Evasive steering direction was found to be most frequently in the direction of travel of the approaching vehicle. The majority of drivers involved in intersection crashes were alert enough to perform an evasive action. Most drivers used a combination of steering and braking to avoid a crash. The average driver attempted to steer and brake at approximately the same time prior to the crash.

Tax Rates and Tax Evasion: Evidence from "Missing Imports" in China.

ERIC Educational Resources Information Center

Fisman, Raymond; Wei, Shang-Jin

2004-01-01

Tax evasion, by its very nature, is difficult to observe. We quantify the effects of tax rates on tax evasion by examining the relationship in China between the tariff schedule and the "evasion gap," which we define as the difference between Hong Kong's reported exports to China at the product level and China's reported imports from Hong…

Hypothalamic Circuits for Predation and Evasion.

PubMed

Li, Yi; Zeng, Jiawei; Zhang, Juen; Yue, Chenyu; Zhong, Weixin; Liu, Zhixiang; Feng, Qiru; Luo, Minmin

2018-02-21

The interactions between predator and prey represent some of the most dramatic events in nature and constitute a matter of life and death for both sides. The hypothalamus has been implicated in driving predation and evasion; however, the exact hypothalamic neural circuits underlying these behaviors remain poorly defined. Here, we demonstrate that inhibitory and excitatory projections from the mouse lateral hypothalamus (LH) to the periaqueductal gray (PAG) in the midbrain drive, respectively, predation and evasion. LH GABA neurons were activated during predation. Optogenetically stimulating PAG-projecting LH GABA neurons drove strong predatory attack, and inhibiting these cells reversibly blocked predation. In contrast, LH glutamate neurons were activated during evasion. Stimulating PAG-projecting LH glutamate neurons drove evasion and inhibiting them impeded predictive evasion. Therefore, the seemingly opposite behaviors of predation and evasion are tightly regulated by two dissociable modular command systems within a single neural projection from the LH to the PAG. VIDEO ABSTRACT. Copyright © 2018 Elsevier Inc. All rights reserved.

Real-time piloted simulation of fully automatic guidance and control for rotorcraft nap-of-the-earth (NOE) flight following planned profiles

NASA Technical Reports Server (NTRS)

Clement, Warren F.; Gorder, Pater J.; Jewell, Wayne F.; Coppenbarger, Richard

1990-01-01

Developing a single-pilot all-weather NOE capability requires fully automatic NOE navigation and flight control. Innovative guidance and control concepts are being investigated to (1) organize the onboard computer-based storage and real-time updating of NOE terrain profiles and obstacles; (2) define a class of automatic anticipative pursuit guidance algorithms to follow the vertical, lateral, and longitudinal guidance commands; (3) automate a decision-making process for unexpected obstacle avoidance; and (4) provide several rapid response maneuvers. Acquired knowledge from the sensed environment is correlated with the recorded environment which is then used to determine an appropriate evasive maneuver if a nonconformity is observed. This research effort has been evaluated in both fixed-base and moving-base real-time piloted simulations thereby evaluating pilot acceptance of the automated concepts, supervisory override, manual operation, and reengagement of the automatic system.

Cigarette tax avoidance and evasion: findings from the International Tobacco Control Policy Evaluation (ITC) Project.

PubMed

Guindon, G Emmanuel; Driezen, Pete; Chaloupka, Frank J; Fong, Geoffrey T

2014-03-01

Decades of research have produced overwhelming evidence that tobacco taxes reduce tobacco use and increase government tax revenue. The magnitude and effectiveness of taxes in reducing tobacco use provide an incentive for tobacco users, manufacturers and others, most notably criminal networks, to devise ways to avoid or evade tobacco taxes. Consequently, tobacco tax avoidance and tax evasion can reduce the public health and fiscal benefit of tobacco taxes. First, this study aims to document, using data from the International Tobacco Control Policy Evaluation Project (ITC), levels and trends in cigarette users' tax avoidance and tax evasion behaviour in a sample of 16 low-, middle- and high-income countries. Second, this study explores factors associated with cigarette tax avoidance and evasion. We used data from ITC surveys conducted in 16 countries to estimate the extent and type of cigarette tax avoidance/evasion between countries and across time. We used self-reported information about the source of a smoker's last purchase of cigarettes or self-reported packaging information, or similar information gathered by the interviewers during face-to-face interviews to measure tax avoidance/evasion behaviours. We used generalised estimating equations to explore individual-level factors that may affect the likelihood of cigarette tax avoidance or evasion in Canada, the USA, the UK and France. We found prevalence estimates of cigarette tax avoidance/evasion vary substantially between countries and across time. In Canada, France and the UK, more than 10% of smokers reported last purchasing cigarettes from low or untaxed sources, while in Malaysia some prevalence estimates suggested substantial cigarette tax avoidance/evasion. We also found important associations between household income and education and the likelihood to engage in tax avoidance/evasion. These associations, however, varied both in direction and magnitude across countries.

Stochastic Game Approach to Guidance Design

DTIC Science & Technology

1988-09-09

maneuverable aircraft, which can employ also electronic counter measures, is formulated as an imper- fect information zero-sum pursuit-evasion game played...on Differential Game Applications [36]. However, some other examples which included " electronic jinking", indicated that in an ECM environment a mixed...radius, b) missile/target maneuver ratio, c) nonlinear maneuver similarity parameter (aE T2 max d) normalized end- game duration, e ) ini’tial end- game

Cigarette tax avoidance and evasion: findings from the International Tobacco Control Policy Evaluation Project

PubMed Central

Guindon, G. Emmanuel; Driezen, Pete; Chaloupka, Frank J.; Fong, Geoffrey T.

2014-01-01

Background Decades of research have produced overwhelming evidence that tobacco taxes reduce tobacco use and increase government tax revenue. The magnitude and effectiveness of taxes at reducing tobacco use provide an incentive for tobacco users, manufacturers and others, most notably criminal networks, to devise ways to avoid or evade tobacco taxes. Consequently, tobacco tax avoidance and tax evasion can reduce the public health and fiscal benefit of tobacco taxes. Objectives First, this study aims to document, using data from the International Tobacco Control Policy Evaluation Project (ITC), levels and trends in cigarette users’ tax avoidance and tax evasion behaviour in a sample of sixteen low-, middle- and high-income countries. Second, this study explores factors associated with cigarette tax avoidance and evasion. Methods We use data from ITC surveys conducted in 16 countries to estimate the extent and the type of cigarette tax avoidance/evasion between countries and across time. We use self-reported information about the source of a smoker’s last purchase of cigarettes or self-reported packaging information, or similar information gathered by the interviewers during face-to-face interviews to measure tax avoidance/evasion behaviours. We use generalized estimating equations (GEE) to explore individual-level factors that may affect the likelihood of cigarette tax avoidance or evasion in Canada, United States, United Kingdom and France. Findings We find prevalence estimates of cigarette tax avoidance/evasion vary substantially between countries and across time. In Canada, France and the United Kingdom, more than 10% of smokers report last purchasing cigarettes from low or untaxed sources while in Malaysia, some prevalence estimates suggest substantial cigarette tax avoidance/evasion. We also find important associations between household income and education and the likelihood to engage in tax avoidance/evasion. These associations, however, vary both in direction and magnitude across countries. PMID:24227541

State road fund revenue collection processes : differences and opportunities of improved efficiency

DOT National Transportation Integrated Search

2001-07-01

Research regarding the administration and collection of road fund revenues has focused on gaining an understanding of the motivations for tax evasion, methods of evasion, and estimates of the magnitude of evasion for individual states. To our knowled...

MONITORING CYCLICAL AIR-WATER ELEMENTAL MERCURY EXCHANGE

EPA Science Inventory

Previous experimental work has demonstrated that elemental mercury evasion from natural water displays a diel cycle; evasion rates during the day can be two to three times evasion rates observed at night. A study with polychlorinated biphenyls (PCBS) found that diurnal PCB air/wa...

31 CFR 587.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 587.204 Section 587.204 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... MONTENEGRO) MILOSEVIC SANCTIONS REGULATIONS Prohibitions § 587.204 Evasions; attempts; conspiracies. (a...

31 CFR 586.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 586.205 Section 586.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... & MONTENEGRO) KOSOVO SANCTIONS REGULATIONS Prohibitions § 586.205 Evasions; attempts; conspiracies. Any...

Does the Sole Description of a Tax Authority Affect Tax Evasion? - The Impact of Described Coercive and Legitimate Power

PubMed Central

Hartl, Barbara; Hofmann, Eva; Gangl, Katharina; Hartner-Tiefenthaler, Martina; Kirchler, Erich

2015-01-01

Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority’s power. Descriptions of the tax authority’s power may affect taxpayers’ beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority’s power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority’s power on participants’ beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2), legitimate power (Experiment 3), and coercive and legitimate power combined (Experiment 4). Further, it is examined whether a contrast of the description of power (low to high power; high to low power) impacts tax evasion (Experiments 2-4). Results show that the amount of fine does not impact tax payments, whereas participants’ beliefs regarding tax authority’s power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority’s power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information. PMID:25923770

Does the sole description of a tax authority affect tax evasion?--the impact of described coercive and legitimate power.

PubMed

Hartl, Barbara; Hofmann, Eva; Gangl, Katharina; Hartner-Tiefenthaler, Martina; Kirchler, Erich

2015-01-01

Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority's power. Descriptions of the tax authority's power may affect taxpayers' beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority's power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority's power on participants' beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2), legitimate power (Experiment 3), and coercive and legitimate power combined (Experiment 4). Further, it is examined whether a contrast of the description of power (low to high power; high to low power) impacts tax evasion (Experiments 2-4). Results show that the amount of fine does not impact tax payments, whereas participants' beliefs regarding tax authority's power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority's power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information.

Fully automatic guidance and control for rotorcraft nap-of-the-Earth flight following planned profiles. Volume 1: Real-time piloted simulation

NASA Technical Reports Server (NTRS)

Clement, Warren F.; Gorder, Peter J.; Jewell, Wayne F.

1991-01-01

Developing a single-pilot, all-weather nap-of-the-earth (NOE) capability requires fully automatic NOE (ANOE) navigation and flight control. Innovative guidance and control concepts are investigated in a four-fold research effort that: (1) organizes the on-board computer-based storage and real-time updating of NOE terrain profiles and obstacles in course-oriented coordinates indexed to the mission flight plan; (2) defines a class of automatic anticipative pursuit guidance algorithms and necessary data preview requirements to follow the vertical, lateral, and longitudinal guidance commands dictated by the updated flight profiles; (3) automates a decision-making process for unexpected obstacle avoidance; and (4) provides several rapid response maneuvers. Acquired knowledge from the sensed environment is correlated with the forehand knowledge of the recorded environment (terrain, cultural features, threats, and targets), which is then used to determine an appropriate evasive maneuver if a nonconformity of the sensed and recorded environments is observed. This four-fold research effort was evaluated in both fixed-based and moving-based real-time piloted simulations, thereby, providing a practical demonstration for evaluating pilot acceptance of the automated concepts, supervisory override, manual operation, and re-engagement of the automatic system. Volume one describes the major components of the guidance and control laws as well as the results of the piloted simulations. Volume two describes the complete mathematical model of the fully automatic guidance system for rotorcraft NOE flight following planned flight profiles.

Fully Automatic Guidance and Control for Rotorcraft Nap-of-the-earth Flight Following Planned Profiles. Volume 2: Mathematical Model

NASA Technical Reports Server (NTRS)

Clement, Warren F.; Gorder, Peter J.; Jewell, Wayne F.

1991-01-01

Developing a single-pilot, all-weather nap-of-the-earth (NOE) capability requires fully automatic NOE (ANOE) navigation and flight control. Innovative guidance and control concepts are investigated in a four-fold research effort that: (1) organizes the on-board computer-based storage and real-time updating of NOE terrain profiles and obstacles in course-oriented coordinates indexed to the mission flight plan; (2) defines a class of automatic anticipative pursuit guidance algorithms and necessary data preview requirements to follow the vertical, lateral, and longitudinal guidance commands dictated by the updated flight profiles; (3) automates a decision-making process for unexpected obstacle avoidance; and (4) provides several rapid response maneuvers. Acquired knowledge from the sensed environment is correlated with the forehand knowledge of the recorded environment (terrain, cultural features, threats, and targets), which is then used to determine an appropriate evasive maneuver if a nonconformity of the sensed and recorded environments is observed. This four-fold research effort was evaluated in both fixed-base and moving-base real-time piloted simulations; thereby, providing a practical demonstration for evaluating pilot acceptance of the automated concepts, supervisory override, manual operation, and re-engagement of the automatic system. Volume one describes the major components of the guidance and control laws as well as the results of the piloted simulations. Volume two describes the complete mathematical model of the fully automatic guidance system for rotorcraft NOE flight following planned flight profiles.

31 CFR 598.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Evasions; attempts; conspiracies. 598.204 Section 598.204 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... REGULATIONS Prohibitions § 598.204 Evasions; attempts; conspiracies. Except to the extent provided in...

31 CFR 598.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Evasions; attempts; conspiracies. 598.204 Section 598.204 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... REGULATIONS Prohibitions § 598.204 Evasions; attempts; conspiracies. Except to the extent provided in...

31 CFR 598.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Evasions; attempts; conspiracies. 598.204 Section 598.204 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... REGULATIONS Prohibitions § 598.204 Evasions; attempts; conspiracies. Except to the extent provided in...

31 CFR 598.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Evasions; attempts; conspiracies. 598.204 Section 598.204 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... REGULATIONS Prohibitions § 598.204 Evasions; attempts; conspiracies. Except to the extent provided in...

31 CFR 542.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 542.205 Section 542.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... § 542.205 Evasions; attempts; conspiracies. (a) Except as otherwise authorized, and notwithstanding any...

31 CFR 548.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 548.205 Section 548.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... § 548.205 Evasions; attempts; conspiracies. (a) Except as otherwise authorized, and notwithstanding any...

31 CFR 594.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 594.205 Section 594.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Prohibitions § 594.205 Evasions; attempts; conspiracies. (a) Except as otherwise authorized, and...

31 CFR 544.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 544.205 Section 544.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... SANCTIONS REGULATIONS Prohibitions § 544.205 Evasions; attempts; conspiracies. (a) Except as otherwise...

31 CFR 541.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 541.204 Section 541.204 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... § 541.204 Evasions; attempts; conspiracies. (a) Except as otherwise authorized, and notwithstanding any...

31 CFR 593.206 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 593.206 Section 593.206 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... SANCTIONS REGULATIONS Prohibitions § 593.206 Evasions; attempts; conspiracies. (a) Except as otherwise...

31 CFR 598.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 598.204 Section 598.204 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... REGULATIONS Prohibitions § 598.204 Evasions; attempts; conspiracies. Except to the extent provided in...

31 CFR 539.203 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 539.203 Section 539.203 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... REGULATIONS Prohibitions § 539.203 Evasions; attempts; conspiracies. Any transaction by any United States...

31 CFR 545.206 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 545.206 Section 545.206 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Prohibitions § 545.206 Evasions; attempts; conspiracies. (a) Except as otherwise authorized, and...

31 CFR 543.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 543.205 Section 543.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Prohibitions § 543.205 Evasions; attempts; conspiracies. (a) Except as otherwise authorized, and...

31 CFR 588.204 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 588.204 Section 588.204 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Prohibitions § 588.204 Evasions; attempts; conspiracies. (a) Except as otherwise authorized, and...

Determination of mercury evasion in a contaminated headwater stream.

PubMed

Maprani, Antu C; Al, Tom A; Macquarrie, Kerry T; Dalziel, John A; Shaw, Sean A; Yeats, Phillip A

2005-03-15

Evasion from first- and second-order streams in a watershed may be a significant factor in the atmospheric recycling of volatile pollutants such as mercury; however, methods developed for the determination of Hg evasion rates from larger water bodies are not expected to provide satisfactory results in highly turbulent and morphologically complex first- and second-order streams. A new method for determining the Hg evasion rates from these streams, involving laboratory gas-indexing experiments and field tracer tests, was developed in this study to estimate the evasion rate of Hg from Gossan Creek, a first-order stream in the Upsalquitch River watershed in northern New Brunswick, Canada. Gossan Creek receives Hg-contaminated groundwater discharge from a gold mine tailings pile. Laboratory gas-indexing experiments provided the ratio of gas-exchange coefficients for zero-valent Hg to propane (tracer gas) of 0.81+/-0.16, suggesting that the evasion mechanism in highly turbulent systems can be described by the surface renewal model with an additional component of enhanced gas evasion probably related to the formation of bubbles. Deliberate field tracer tests with propane and chloride tracers were found to be a reliable and practical method for the determination of gas-exchange coefficients for small streams. Estimation of Hg evasion from the first 1 km of Gossan Creek indicates that about 6.4 kg of Hg per year is entering the atmosphere, which is a significant fraction of the regional sources of Hg to the atmosphere.

77 FR 35351

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-13

... responsibility, affiliation, or other connection in the conduct of trade or business in order to prevent evasion... necessary to avoid evasion of the denial order against Vaghari. As provided in Section 766.23 of the... to Vaghari would be necessary to prevent evasion of a denial order imposed against Vaghari. In...

31 CFR 538.211 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 538.211 Section 538.211 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... § 538.211 Evasions; attempts; conspiracies. Any transaction by any United States person or within the...

31 CFR 592.202 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 592.202 Section 592.202 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Prohibitions § 592.202 Evasions; attempts; conspiracies. (a) Notwithstanding the existence of any rights or...

Immune evasion in cancer: Mechanistic basis and therapeutic strategies.

PubMed

Vinay, Dass S; Ryan, Elizabeth P; Pawelec, Graham; Talib, Wamidh H; Stagg, John; Elkord, Eyad; Lichtor, Terry; Decker, William K; Whelan, Richard L; Kumara, H M C Shantha; Signori, Emanuela; Honoki, Kanya; Georgakilas, Alexandros G; Amin, Amr; Helferich, William G; Boosani, Chandra S; Guha, Gunjan; Ciriolo, Maria Rosa; Chen, Sophie; Mohammed, Sulma I; Azmi, Asfar S; Keith, W Nicol; Bilsland, Alan; Bhakta, Dipita; Halicka, Dorota; Fujii, Hiromasa; Aquilano, Katia; Ashraf, S Salman; Nowsheen, Somaira; Yang, Xujuan; Choi, Beom K; Kwon, Byoung S

2015-12-01

Cancer immune evasion is a major stumbling block in designing effective anticancer therapeutic strategies. Although considerable progress has been made in understanding how cancers evade destructive immunity, measures to counteract tumor escape have not kept pace. There are a number of factors that contribute to tumor persistence despite having a normal host immune system. Immune editing is one of the key aspects why tumors evade surveillance causing the tumors to lie dormant in patients for years through "equilibrium" and "senescence" before re-emerging. In addition, tumors exploit several immunological processes such as targeting the regulatory T cell function or their secretions, antigen presentation, modifying the production of immune suppressive mediators, tolerance and immune deviation. Besides these, tumor heterogeneity and metastasis also play a critical role in tumor growth. A number of potential targets like promoting Th1, NK cell, γδ T cell responses, inhibiting Treg functionality, induction of IL-12, use of drugs including phytochemicals have been designed to counter tumor progression with much success. Some natural agents and phytochemicals merit further study. For example, use of certain key polysaccharide components from mushrooms and plants have shown to possess therapeutic impact on tumor-imposed genetic instability, anti-growth signaling, replicative immortality, dysregulated metabolism etc. In this review, we will discuss the advances made toward understanding the basis of cancer immune evasion and summarize the efficacy of various therapeutic measures and targets that have been developed or are being investigated to enhance tumor rejection. Copyright © 2015 Elsevier Ltd. All rights reserved.

31 CFR 560.203 - Evasions; attempts.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts. 560.203 Section 560.203 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF... Evasions; attempts. Any transaction by any United States person or within the United States that evades or...

Seeing Themselves through Borrowed Eyes: Asian Americans in Ethnic Ambivalence/Evasion.

ERIC Educational Resources Information Center

Tse, Lucy

1998-01-01

Focuses on the second stage of ethnic identity development, Ethnic Ambivalence/Evasion, experienced by Asian Americans through 39 personal narratives. Ethnic Ambivalence/Evasion, one of four identified stages that culminate with ethnic identity incorporation, typically occurs during the years of childhood and adolescence, and so is a stage…

31 CFR 535.208 - Evasions; effective date.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; effective date. 535.208 Section 535.208 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... § 535.208 Evasions; effective date. (a) Any transaction for the purpose of, or which has the effect of...

31 CFR 537.206 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 537.206 Section 537.206 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... § 537.206 Evasions; attempts; conspiracies. (a) Any transaction by a U.S. person or within the United...

Global carbon dioxide emissions from inland waters

USGS Publications Warehouse

Raymond, Peter A.; Hartmann, Jens; Lauerwald, Ronny; Sobek, Sebastian; McDonald, Cory P.; Hoover, Mark; Butman, David; Striegl, Robert G.; Mayorga, Emilio; Humborg, Christoph; Kortelainen, Pirkko; Durr, Hans H.; Meybeck, Michel; Ciais, Philippe; Guth, Peter

2013-01-01

Carbon dioxide (CO2) transfer from inland waters to the atmosphere, known as CO2 evasion, is a component of the global carbon cycle. Global estimates of CO2 evasion have been hampered, however, by the lack of a framework for estimating the inland water surface area and gas transfer velocity and by the absence of a global CO2 database. Here we report regional variations in global inland water surface area, dissolved CO2 and gas transfer velocity. We obtain global CO2 evasion rates of 1.8   petagrams of carbon (Pg C) per year from streams and rivers and 0.32  Pg C yr−1 from lakes and reservoirs, where the upper and lower limits are respectively the 5th and 95th confidence interval percentiles. The resulting global evasion rate of 2.1 Pg C yr−1 is higher than previous estimates owing to a larger stream and river evasion rate. Our analysis predicts global hotspots in stream and river evasion, with about 70 per cent of the flux occurring over just 20 per cent of the land surface. The source of inland water CO2 is still not known with certainty and new studies are needed to research the mechanisms controlling CO2 evasion globally.

Predictive Virtual Infection Modeling of Fungal Immune Evasion in Human Whole Blood.

PubMed

Prauße, Maria T E; Lehnert, Teresa; Timme, Sandra; Hünniger, Kerstin; Leonhardt, Ines; Kurzai, Oliver; Figge, Marc Thilo

2018-01-01

Bloodstream infections by the human-pathogenic fungi Candida albicans and Candida glabrata increasingly occur in hospitalized patients and are associated with high mortality rates. The early immune response against these fungi in human blood comprises a concerted action of humoral and cellular components of the innate immune system. Upon entering the blood, the majority of fungal cells will be eliminated by innate immune cells, i.e., neutrophils and monocytes. However, recent studies identified a population of fungal cells that can evade the immune response and thereby may disseminate and cause organ dissemination, which is frequently observed during candidemia. In this study, we investigate the so far unresolved mechanism of fungal immune evasion in human whole blood by testing hypotheses with the help of mathematical modeling. We use a previously established state-based virtual infection model for whole-blood infection with C. albicans to quantify the immune response and identified the fungal immune-evasion mechanism. While this process was assumed to be spontaneous in the previous model, we now hypothesize that the immune-evasion process is mediated by host factors and incorporate such a mechanism in the model. In particular, we propose, based on previous studies that the fungal immune-evasion mechanism could possibly arise through modification of the fungal surface by as of yet unknown proteins that are assumed to be secreted by activated neutrophils. To validate or reject any of the immune-evasion mechanisms, we compared the simulation of both immune-evasion models for different infection scenarios, i.e., infection of whole blood with either C. albicans or C. glabrata under non-neutropenic and neutropenic conditions. We found that under non-neutropenic conditions, both immune-evasion models fit the experimental data from whole-blood infection with C. albicans and C. glabrata . However, differences between the immune-evasion models could be observed for the infection outcome under neutropenic conditions with respect to the distribution of fungal cells across the immune cells. Based on these predictions, we suggested specific experimental studies that might allow for the validation or rejection of the proposed immune-evasion mechanism.

Predictive Virtual Infection Modeling of Fungal Immune Evasion in Human Whole Blood

PubMed Central

Prauße, Maria T. E.; Lehnert, Teresa; Timme, Sandra; Hünniger, Kerstin; Leonhardt, Ines; Kurzai, Oliver; Figge, Marc Thilo

2018-01-01

Bloodstream infections by the human-pathogenic fungi Candida albicans and Candida glabrata increasingly occur in hospitalized patients and are associated with high mortality rates. The early immune response against these fungi in human blood comprises a concerted action of humoral and cellular components of the innate immune system. Upon entering the blood, the majority of fungal cells will be eliminated by innate immune cells, i.e., neutrophils and monocytes. However, recent studies identified a population of fungal cells that can evade the immune response and thereby may disseminate and cause organ dissemination, which is frequently observed during candidemia. In this study, we investigate the so far unresolved mechanism of fungal immune evasion in human whole blood by testing hypotheses with the help of mathematical modeling. We use a previously established state-based virtual infection model for whole-blood infection with C. albicans to quantify the immune response and identified the fungal immune-evasion mechanism. While this process was assumed to be spontaneous in the previous model, we now hypothesize that the immune-evasion process is mediated by host factors and incorporate such a mechanism in the model. In particular, we propose, based on previous studies that the fungal immune-evasion mechanism could possibly arise through modification of the fungal surface by as of yet unknown proteins that are assumed to be secreted by activated neutrophils. To validate or reject any of the immune-evasion mechanisms, we compared the simulation of both immune-evasion models for different infection scenarios, i.e., infection of whole blood with either C. albicans or C. glabrata under non-neutropenic and neutropenic conditions. We found that under non-neutropenic conditions, both immune-evasion models fit the experimental data from whole-blood infection with C. albicans and C. glabrata. However, differences between the immune-evasion models could be observed for the infection outcome under neutropenic conditions with respect to the distribution of fungal cells across the immune cells. Based on these predictions, we suggested specific experimental studies that might allow for the validation or rejection of the proposed immune-evasion mechanism. PMID:29619027

Computing danger zones for provably safe closely spaced parallel approaches: Theory and experiment

NASA Astrophysics Data System (ADS)

Teo, Rodney

In poor visibility, paired approaches to airports with closely spaced parallel runways are not permitted, thus halving the arrival rate. With Global Positioning System technology, datalinks and cockpit displays, this could be averted. One important problem is ensuring safety during a blundered approach by one aircraft. This is on-going research. A danger zone around the blunderer is required. If the correct danger zone could be calculated, then it would be possible to get 100% of clear-day capacity in poor-visibility days even on 750 foot runways. The danger zones vary significantly (during an approach) and calculating them in real time would be very significant. Approximations (e.g. outer bounds) are not good enough. This thesis presents a way to calculate these danger zones in real time for a very broad class of blunder trajectories. The approach in this thesis differs from others in that it guarantees safety for any possible blunder trajectory as long as the speeds and turn rates of the blunder are within certain bounds. In addition, the approach considers all emergency evasive maneuvers whose speeds and turn rates are within certain bounds about a nominal emergency evasive maneuver. For all combinations of these blunder and evasive maneuver trajectories, it guarantees that the evasive maneuver is safe. For more than 1 million simulation runs, the algorithm shows a 100% rate of Successful Alerts and a 0% rate of Collisions Given an Alert. As an experimental testbed, two 10-ft wingspan fully autonomous unmanned aerial vehicles and a ground station are developed together with J. S. Jang. The development includes the design and flight testing of automatic controllers. The testbed is used to demonstrate the algorithm implementation through an autonomous closely spaced parallel approach, with one aircraft programmed to blunder. The other aircraft responds according to the result of the algorithm on board it and evades autonomously when required. This experimental demonstration is successfully conducted, showing the implementation of the algorithm, in particular, demonstrating that it can run in real time. Finally; with the necessary sensors and datalink, and the appropriate procedures in place, the algorithm developed in this thesis will enable 100% of clear-day capacity in poor-visibility days even on 750 foot runways.

26 CFR 301.6111-2 - Confidential corporate tax shelters.

Code of Federal Regulations, 2011 CFR

2011-04-01

... purpose of the structure of which is the avoidance or evasion of Federal income tax, as described in... income tax—(1) In general. The avoidance or evasion of Federal income tax will be considered a... purpose of the shelter is the avoidance or evasion of the first person's Federal income tax. For purposes...

15 CFR 766.23 - Related persons.

Code of Federal Regulations, 2010 CFR

2010-01-01

... PROCEEDINGS § 766.23 Related persons. (a) General. In order to prevent evasion, certain types of orders under... applicable to that person in order to prevent evasion of the order, BIS shall, except in an ex parte... respondent finds that the order should be made applicable to that person in order to prevent evasion of the...

Immune defence, parasite evasion strategies and their relevance for ‘macroscopic phenomena’ such as virulence

PubMed Central

Schmid-Hempel, Paul

2008-01-01

The discussion of host–parasite interactions, and of parasite virulence more specifically, has so far, with a few exceptions, not focused much attention on the accumulating evidence that immune evasion by parasites is not only almost universal but also often linked to pathogenesis, i.e. the appearance of virulence. Now, the immune evasion hypothesis offers a deeper insight into the evolution of virulence than previous hypotheses. Sensitivity analysis for parasite fitness and life-history theory shows promise to generate a more general evolutionary theory of virulence by including a major element, immune evasion to prevent parasite clearance from the host. Also, the study of dose–response relationships and multiple infections should be particularly illuminating to understand the evolution of virulence. Taking into account immune evasion brings immunological processes to the core of understanding the evolution of parasite virulence and for a range of related issues such as dose, host specificity or immunopathology. The aim of this review is to highlight the mechanism underlying immune evasion and to discuss possible consequences for the evolutionary ecology analysis of host–parasite interactions. PMID:18930879

Runway Safety Monitor Algorithm for Runway Incursion Detection and Alerting

NASA Technical Reports Server (NTRS)

Green, David F., Jr.; Jones, Denise R. (Technical Monitor)

2002-01-01

The Runway Safety Monitor (RSM) is an algorithm for runway incursion detection and alerting that was developed in support of NASA's Runway Incursion Prevention System (RIPS) research conducted under the NASA Aviation Safety Program's Synthetic Vision System element. The RSM algorithm provides pilots with enhanced situational awareness and warnings of runway incursions in sufficient time to take evasive action and avoid accidents during landings, takeoffs, or taxiing on the runway. The RSM currently runs as a component of the NASA Integrated Display System, an experimental avionics software system for terminal area and surface operations. However, the RSM algorithm can be implemented as a separate program to run on any aircraft with traffic data link capability. The report documents the RSM software and describes in detail how RSM performs runway incursion detection and alerting functions for NASA RIPS. The report also describes the RIPS flight tests conducted at the Dallas-Ft Worth International Airport (DFW) during September and October of 2000, and the RSM performance results and lessons learned from those flight tests.

75 FR 63802 - Action Affecting Export Privileges; Parto Abgardan Cooling Towers Co.

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-18

... to prevent evasion, certain types of orders under [Part 766] may be made applicable not only to the... order to prevent evasion of that denial order, the Assistant Secretary shall issue or amend the order... the Denial Order is justified in order to prevent evasion of that Order. I find that BIS has presented...

75 FR 32740 - Action Affecting Export Privileges; Aaron Robert Henderson and Valhalla Tactical Supply

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-09

... in the conduct of trade or business in order to prevent evasion of a denial order. Because Henderson... is necessary to avoid evasion of the denial order against Henderson. As provided in Section 766.23 of... entity related to Henderson would be necessary to prevent evasion of a denial order imposed against...

Obstacle evasion in free-space optical communications utilizing Airy beams.

PubMed

Zhu, Guoxuan; Wen, Yuanhui; Wu, Xiong; Chen, Yujie; Liu, Jie; Yu, Siyuan

2018-03-15

A high speed free-space optical communication system capable of self-bending signal transmission around line-of-sight obstacles is proposed and demonstrated. Airy beams are generated and controlled to achieve different propagating trajectories, and the signal transmission characteristics of these beams around the obstacle are investigated. Our results confirm that, by optimizing their ballistic trajectories, Airy beams are able to bypass obstacles with more signal energy and thus improve the communication performance compared with normal Gaussian beams.

Obstacle evasion in free-space optical communications utilizing Airy beams

NASA Astrophysics Data System (ADS)

Zhu, Guoxuan; Wen, Yuanhui; Wu, Xiong; Chen, Yujie; Liu, Jie; Yu, Siyuan

2018-03-01

A high speed free-space optical communication system capable of self-bending signal transmission around line-of-sight obstacles is proposed and demonstrated. Airy beams are generated and controlled to achieve different propagating trajectories, and the signal transmission characteristics of these beams around the obstacle are investigated. Our results confirm that, by optimising their ballistic trajectories, Airy beams are able to bypass obstacles with more signal energy and thus improve the communication performance compared with normal Gaussian beams.

26 CFR 1.269-3 - Instances in which section 269(a) disallows a deduction, credit, or other allowance.

Code of Federal Regulations, 2011 CFR

2011-04-01

... made must have been the evasion or avoidance of Federal income tax by securing the benefit of a... evasion or avoidance of Federal income tax: (1) A corporation or other business enterprise (or the... purpose of evasion or avoidance of Federal income tax, the fact that a governmental unit did not seek a...

75 FR 56504 - Action Affecting Export Privileges; Rigel Optics, Inc. and Donald Wayne Hatch; Order Denying...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-16

... responsibility, affiliation, or other connection in the conduct of trade or business in order to prevent evasion... believes that naming Hatch as a related person to Rigel Optics is necessary to avoid evasion of the denial... necessary to prevent evasion of a denial order imposed against Rigel Optics. In providing such notice, I...

75 FR 63801 - Action Affecting Export Privileges; Joseph Piquet and Related Person Alphatronx, Inc.

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-18

... evasion, certain types of orders under this part may be made applicable not only to the respondent, but... it is necessary to add this entity to the Piquet Denial Order in order to avoid evasion of that Order... would be necessary to prevent evasion of a denial order imposed against Piquet. In providing such notice...

The Tax Compliance Demand Curve: A Diagrammatical Approach to Income Tax Evasion

ERIC Educational Resources Information Center

Yaniv, Gideon

2009-01-01

One of the most interesting results in the tax evasion literature is that an increase in the income tax rate would increase tax compliance. Despite its peculiarity, this result has gained acceptance as a cornerstone for further developments of the rational tax evasion model. However, because of the mathematical format by which it is conveyed, this…

75 FR 32743 - Action Affecting Export Privileges; Green Supply, Inc.; Robert Leland Green and William Robert...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-09

... responsibility, affiliation, or other connection in the conduct of trade or business in order to prevent evasion... to GSI is necessary to avoid evasion of the denial order against GSI. As provided in Section 766.23... believes naming them as persons related to GSI would be necessary to prevent evasion of a denial order...

Identifying Bacterial Immune Evasion Proteins Using Phage Display.

PubMed

Fevre, Cindy; Scheepmaker, Lisette; Haas, Pieter-Jan

2017-01-01

Methods aimed at identification of immune evasion proteins are mainly rely on in silico prediction of sequence, structural homology to known evasion proteins or use a proteomics driven approach. Although proven successful these methods are limited by a low efficiency and or lack of functional identification. Here we describe a high-throughput genomic strategy to functionally identify bacterial immune evasion proteins using phage display technology. Genomic bacterial DNA is randomly fragmented and ligated into a phage display vector that is used to create a phage display library expressing bacterial secreted and membrane bound proteins. This library is used to select displayed bacterial secretome proteins that interact with host immune components.

Tax Evasion and Nonequilibrium Model on Apollonian Networks

NASA Astrophysics Data System (ADS)

Lima, F. W. S.

2012-11-01

The Zaklan model had been proposed and studied recently using the equilibrium Ising model on square lattices (SLs) by [G. Zaklan, F. Westerhoff and D. Stauffer, J. Econ. Interact. Coord.4, 1 (2008), arXiv:0801.2980; G. Zaklan, F. W. S. Lima and F. Westerhoff, Physica A387, 5857 (2008)], near the critical temperature of the Ising model presenting a well-defined phase transition; but on normal and modified Apollonian networks (ANs), [J. S. Andrade, Jr., H. J. Herrmann, R. F. S. Andrade, and L. R. da Silva, Phys. Rev. Lett.94, 018702 (2005); R. F. S. Andrade, J. S. Andrade Jr. and H. J. Herrmann, Phys. Rev. E79, 036105 (2009)] studied the equilibrium Ising model. They showed the equilibrium Ising model not to present on ANs a phase transition of the type for the 2D Ising model. Here, using agent-based Monte Carlo simulations, we study the Zaklan model with the well-known majority-vote model (MVM) with noise and apply it to tax evasion on ANs, to show that differently from the Ising model the MVM on ANs presents a well-defined phase transition. To control the tax evasion in the economics model proposed by Zaklan et al., MVM is applied in the neighborhood of the critical noise qc to the Zaklan model. Here we show that the Zaklan model is robust because this can also be studied, besides using equilibrium dynamics of Ising model, through the nonequilibrium MVM and on various topologies giving the same behavior regardless of dynamic or topology used here.

The Evasion of the Text; Invasion of the Text; Again, Evasion of the Text; "The Eagle and the Mole": The Affective Fallacy Revisited.

ERIC Educational Resources Information Center

Ducharme, Edward R.; And Others

1970-01-01

Three writers debate whether English teachers should depend on external or internal criteria when analyzing and teaching literature. Each writer discusses the meaning of Elinor Wylie's poem, "The Eagle and the Mole," according to his particular view of literary analysis. Edward Ducharme, in "The Evasion of the Text," submits…

Lapse of time effects on tax evasion in an agent-based econophysics model

NASA Astrophysics Data System (ADS)

Seibold, Götz; Pickhardt, Michael

2013-05-01

We investigate an inhomogeneous Ising model in the context of tax evasion dynamics where different types of agents are parameterized via local temperatures and magnetic fields. In particular, we analyze the impact of lapse of time effects (i.e. backauditing) and endogenously determined penalty rates on tax compliance. Both features contribute to a microfoundation of agent-based econophysics models of tax evasion.

Cytomegalovirus immune evasion of myeloid lineage cells.

PubMed

Brinkmann, Melanie M; Dağ, Franziska; Hengel, Hartmut; Messerle, Martin; Kalinke, Ulrich; Čičin-Šain, Luka

2015-06-01

Cytomegalovirus (CMV) evades the immune system in many different ways, allowing the virus to grow and its progeny to spread in the face of an adverse environment. Mounting evidence about the antiviral role of myeloid immune cells has prompted the research of CMV immune evasion mechanisms targeting these cells. Several cells of the myeloid lineage, such as monocytes, dendritic cells and macrophages, play a role in viral control, but are also permissive for CMV and are naturally infected by it. Therefore, CMV evasion of myeloid cells involves mechanisms that qualitatively differ from the evasion of non-CMV-permissive immune cells of the lymphoid lineage. The evasion of myeloid cells includes effects in cis, where the virus modulates the immune signaling pathways within the infected myeloid cell, and those in trans, where the virus affects somatic cells targeted by cytokines released from myeloid cells. This review presents an overview of CMV strategies to modulate and evade the antiviral activity of myeloid cells in cis and in trans.

Linking tumor glycolysis and immune evasion in cancer: Emerging concepts and therapeutic opportunities.

PubMed

Ganapathy-Kanniappan, Shanmugasundaram

2017-08-01

Metabolic reprogramming and immune evasion are two hallmarks of cancer. Metabolic reprogramming is exemplified by cancer's propensity to utilize glucose at an exponential rate which in turn is linked with "aerobic glycolysis", popularly known as the "Warburg effect". Tumor glycolysis is pivotal for the efficient management of cellular bioenergetics and uninterrupted cancer growth. Mounting evidence suggests that tumor glycolysis also plays a key role in instigating immunosuppressive networks that are critical for cancer cells to escape immune surveillance ("immune evasion"). Recent data show that induction of cellular stress or metabolic dysregulation sensitize cancer cells to antitumor immune cells implying that metabolic reprogramming and immune evasion harmonize during cancer progression. However, the molecular link between these two hallmarks of cancer remains obscure. In this review the molecular intricacies of tumor glycolysis that facilitate immune evasion has been discussed in the light of recent research to explore immunotherapeutic potential of targeting cancer metabolism. Copyright © 2017 Elsevier B.V. All rights reserved.

Trust-Based Analysis of an Air Force Collision Avoidance System

DTIC Science & Technology

2015-12-01

that test pilots’ trust depended on a number of factors, including the development of a nuisance free algorithm, designing fly-up evasive maneuvers...revealed that test pilots’ trust depended on a number of factors, including the development of a nuisance- free algorithm, designing fly-up evasive ...the terrain collision evasion maneuver. To overcome these limitations, Auto-GCAS was developed with a number of innovative approaches and solutions

Staphylococcal Immune Evasion Proteins: Structure, Function, and Host Adaptation.

PubMed

Koymans, Kirsten J; Vrieling, Manouk; Gorham, Ronald D; van Strijp, Jos A G

2017-01-01

Staphylococcus aureus is a successful human and animal pathogen. Its pathogenicity is linked to its ability to secrete a large amount of virulence factors. These secreted proteins interfere with many critical components of the immune system, both innate and adaptive, and hamper proper immune functioning. In recent years, numerous studies have been conducted in order to understand the molecular mechanism underlying the interaction of evasion molecules with the host immune system. Structural studies have fundamentally contributed to our understanding of the mechanisms of action of the individual factors. Furthermore, such studies revealed one of the most striking characteristics of the secreted immune evasion molecules: their conserved structure. Despite high-sequence variability, most immune evasion molecules belong to a small number of structural categories. Another remarkable characteristic is that S. aureus carries most of these virulence factors on mobile genetic elements (MGE) or ex-MGE in its accessory genome. Coevolution of pathogen and host has resulted in immune evasion molecules with a highly host-specific function and prevalence. In this review, we explore how these shared structures and genomic locations relate to function and host specificity. This is discussed in the context of therapeutic options for these immune evasion molecules in infectious as well as in inflammatory diseases.

Evasion of CO2 from streams - the dominant component of the carbon export through the aquatic conduit in a boreal landscape.

PubMed

Wallin, Marcus B; Grabs, Thomas; Buffam, Ishi; Laudon, Hjalmar; Agren, Ånneli; Öquist, Mats G; Bishop, Kevin

2013-03-01

Evasion of gaseous carbon (C) from streams is often poorly quantified in landscape C budgets. Even though the potential importance of the capillary network of streams as C conduits across the land-water-atmosphere interfaces is sometimes mentioned, low-order streams are often left out of budget estimates due to being poorly characterized in terms of gas exchange and even areal surface coverage. We show that evasion of C is greater than all the total dissolved C (both organic and inorganic) exported downstream in the waters of a boreal landscape. In this study evasion of carbon dioxide (CO2 ) from running waters within a 67 km(2) boreal catchment was studied. During a 4 year period (2006-2009) 13 streams were sampled on 104 different occasions for dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). From a locally determined model of gas exchange properties, we estimated the daily CO2 evasion with a high-resolution (5 × 5 m) grid-based stream evasion model comprising the entire ~100 km stream network. Despite the low areal coverage of stream surface, the evasion of CO2 from the stream network constituted 53% (5.0 (±1.8) g C m(-2)  yr(-1) ) of the entire stream C flux (9.6 (±2.4) g C m(-2)  yr(-1) ) (lateral as DIC, DOC, and vertical as CO2 ). In addition, 72% of the total CO2 loss took place already in the first- and second-order streams. This study demonstrates the importance of including CO2 evasion from low-order boreal streams into landscape C budgets as it more than doubled the magnitude of the aquatic conduit for C from this landscape. Neglecting this term will consequently result in an overestimation of the terrestrial C sink strength in the boreal landscape. © 2012 Blackwell Publishing Ltd.

Multivariate Analysis for the Choice and Evasion of the Student in a Higher Educational Institution from Southern of Santa Catarina, in Brazil

ERIC Educational Resources Information Center

Queiroz, Fernanda Cristina Barbosa Pereira; Samohyl, Robert Wayne; Queiroz, Jamerson Viegas; Lima, Nilton Cesar; de Souza, Gustavo Henrique Silva

2014-01-01

This paper aims to develop and implement a method to identify the causes of the choice of a course and the reasons for evasion in higher education. This way, we sought to identify the factors that influence student choice to opt for Higher Education Institution parsed, as well as the factors influencing its evasion. The methodology employed was…

Greece’s Debt Crisis: Overview, Policy Responses, and Implications

DTIC Science & Technology

2010-04-07

inefficient public administration in Greece, costly pension and healthcare systems, tax evasion , and a general “absence of the will to maintain fiscal...2005 to 24% of GDP in 2050. Weak revenue collection has also contributed to Greece’s budget deficits. Many economists identify tax evasion and...the informal economy in Greece to represent between 25%-30% of GDP.24 Observers offer a variety of explanations for the prevalence of tax evasion in

Bilateral flight muscle activity predicts wing kinematics and 3-dimensional body orientation of locusts responding to looming objects.

PubMed

McMillan, Glyn A; Loessin, Vicky; Gray, John R

2013-09-01

We placed locusts in a wind tunnel using a loose tether design that allowed for motion in all three rotational degrees of freedom during presentation of a computer-generated looming disc. High-speed video allowed us to extract wing kinematics, abdomen position and 3-dimensional body orientation. Concurrent electromyographic (EMG) recordings monitored bilateral activity from the first basalar depressor muscles (m97) of the forewings, which are implicated in flight steering. Behavioural responses to a looming disc included cessation of flight (wings folded over the body), glides and active steering during sustained flight in addition to a decrease and increase in wingbeat frequency prior to and during, respectively, an evasive turn. Active steering involved shifts in bilateral m97 timing, wing asymmetries and whole-body rotations in the yaw (ψ), pitch (χ) and roll (η) planes. Changes in abdomen position and hindwing asymmetries occurred after turns were initiated. Forewing asymmetry and changes in η were most highly correlated with m97 spike latency. Correlations also increased as the disc approached, peaking prior to collision. On the inside of a turn, m97 spikes occurred earlier relative to forewing stroke reversal and bilateral timing corresponded to forewing asymmetry as well as changes in whole-body rotation. Double spikes in each m97 occurred most frequently at or immediately prior to the time the locusts turned, suggesting a behavioural significance. These data provide information on mechanisms underlying 3-dimensional flight manoeuvres and will be used to drive a closed loop flight simulator to study responses of motion-sensitive visual neurons during production of realistic behaviours.

Light oiling of feathers increases flight energy expenditure in a migratory shorebird.

PubMed

Maggini, Ivan; Kennedy, Lisa V; Macmillan, Alexander; Elliott, Kyle H; Dean, Karen; Guglielmo, Christopher G

2017-07-01

Flying birds depend on their feathers to undertake most activities, and maintain them in peak condition through periodic molt and frequent preening. Even small exposures to crude oil reduce the integrity of feathers, and could impair flight performance. We trained wild western sandpipers ( Calidris mauri ) to perform endurance flights in a wind tunnel, and used magnetic resonance body composition analysis to measure energy expenditure after birds were exposed to weathered MC252 crude oil from the Deepwater Horizon oil spill. The cost of transport was 0.26±0.04 kJ km -1 in controls, and increased by 22% when the trailing edges of the wing and tail were oiled (<20% of body surface; considered light oiling). Additional crude oil on breast and back feathers (∼30% total surface; moderate oiling) increased the cost of transport by 45% above controls. Oiling tended to decrease flight control, and only half of moderately oiled birds completed the flight test. We then flew birds at a range of speeds to estimate basic kinematic parameters. At low speeds, light and moderately oiled birds had larger wingbeat amplitudes than controls, while moderately oiled birds showed greater wingbeat frequencies across all speeds, and a shift in optimal flight speed towards higher wind speeds. We suggest these changes reflect poorer lift production and increased drag on the wings and body. Oiling will increase the difficulty and energy costs of locomotion for daily and seasonal activities such as foraging, predator evasion, territory defense, courtship, chick provisioning, commuting and long-distance migration. These sub-lethal effects must be considered in oil spill impact assessments. © 2017. Published by The Company of Biologists Ltd.

14 CFR 135.345 - Pilots: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2014 CFR

2014-01-01

...; (9) Flight planning; (10) Each normal and emergency procedure; and (11) The approved Aircraft Flight... following, as applicable to their duties: (a) General subjects— (1) The certificate holder's flight locating...., flight controls, electrical, and hydraulic), other systems, as appropriate, principles of normal...

14 CFR 135.345 - Pilots: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2013 CFR

2013-01-01

...; (9) Flight planning; (10) Each normal and emergency procedure; and (11) The approved Aircraft Flight... following, as applicable to their duties: (a) General subjects— (1) The certificate holder's flight locating...., flight controls, electrical, and hydraulic), other systems, as appropriate, principles of normal...

14 CFR 135.345 - Pilots: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2012 CFR

2012-01-01

...; (9) Flight planning; (10) Each normal and emergency procedure; and (11) The approved Aircraft Flight... following, as applicable to their duties: (a) General subjects— (1) The certificate holder's flight locating...., flight controls, electrical, and hydraulic), other systems, as appropriate, principles of normal...

14 CFR 135.345 - Pilots: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2011 CFR

2011-01-01

...; (9) Flight planning; (10) Each normal and emergency procedure; and (11) The approved Aircraft Flight... following, as applicable to their duties: (a) General subjects— (1) The certificate holder's flight locating...., flight controls, electrical, and hydraulic), other systems, as appropriate, principles of normal...

14 CFR 135.345 - Pilots: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2010 CFR

2010-01-01

...; (9) Flight planning; (10) Each normal and emergency procedure; and (11) The approved Aircraft Flight... following, as applicable to their duties: (a) General subjects— (1) The certificate holder's flight locating...., flight controls, electrical, and hydraulic), other systems, as appropriate, principles of normal...

Behavioral responses of big brown bats to dives by praying mantises.

PubMed

Ghose, Kaushik; Triblehorn, Jeffrey D; Bohn, Kari; Yager, David D; Moss, Cynthia F

2009-03-01

Insectivorous echolocating bats face a formidable array of defenses employed by their airborne prey. One such insect defense is the ultrasound-triggered dive, which is a sudden, rapid drop in altitude, sometimes all the way to the ground. Although many previous studies have investigated the dynamics of such dives and their effect on insect survival rate, there has been little work on how bats may adapt to such an insect defense employed in the middle of pursuit. In this study we investigated how big brown bats (Eptesicus fuscus) adjust their pursuit strategy when flying praying mantises (Parasphendale agrionina) execute evasive, ultrasound-triggered dives. Although the mantis dive occasionally forced the bat to completely abort its chase (25% trials), in a number of cases (75% trials) the bat followed the mantis into the dive. In such cases the bat kept its sonar beam locked onto the target and maneuvered to maintain the same time efficient strategy it adopted during level flight pursuit, though it was ultimately defeated by the dive. This study suggests that although the mantis dive can be effective in evading the bat, it does not always deter the bat from continuing pursuit and, given enough altitude, the bat can potentially capture diving prey using the same flight strategy it employs to intercept prey in level flight.

The Role of PD-1 Ligand in Immune Evasion by Breast Cancer

DTIC Science & Technology

2005-05-01

with anti-CD11c-PE and either anti-PD-L1-FITC or anti-PD-L2-FITC and an- alyzed by flow cytometry . 1260 BLOCKADE OF PD-L ON DC ENHANCES T CELL... surface staining. . In order to accomplish these epitope blocking studies, we made 300.19 and CHO cells transfected with PD-L1 or PD-L2. For anti...Key Research Accomplishments 1. PD-L1 but not PD-L2 is highly expressed on the cell surface of breast cancer cells but not on normal breast

Functional Motifs Responsible for Human Metapneumovirus M2-2-mediated Innate Immune Evasion

PubMed Central

Chen, Yu; Deng, Xiaoling; Deng, Junfang; Zhou, Jiehua; Ren, Yuping; Liu, Shengxuan; Prusak, Deborah J.; Wood, Thomas G.; Bao, Xiaoyong

2016-01-01

Human metapneumovirus (hMPV) is a major cause of lower respiratory infection in young children. Repeated infections occur throughout life, but its immune evasion mechanisms are largely unknown. We recently found that hMPV M2-2 protein elicits immune evasion by targeting mitochondrial antiviral-signaling protein (MAVS), an antiviral signaling molecule. However, the molecular mechanisms underlying such inhibition are not known. Our mutagenesis studies revealed that PDZ-binding motifs, 29-DEMI-32 and 39-KEALSDGI-46, located in an immune inhibitory region of M2-2, are responsible for M2-2-mediated immune evasion. We also found both motifs prevent TRAF5 and TRAF6, the MAVS downstream adaptors, to be recruited to MAVS, while the motif 39-KEALSDGI-46 also blocks TRAF3 migrating to MAVS. In parallel, these TRAFs are important in activating transcription factors NF-kB and/or IRF-3 by hMPV. Our findings collectively demonstrate that M2-2 uses its PDZ motifs to launch the hMPV immune evasion through blocking the interaction of MAVS and its downstream TRAFs. PMID:27743962

Adversarial Feature Selection Against Evasion Attacks.

PubMed

Zhang, Fei; Chan, Patrick P K; Biggio, Battista; Yeung, Daniel S; Roli, Fabio

2016-03-01

Pattern recognition and machine learning techniques have been increasingly adopted in adversarial settings such as spam, intrusion, and malware detection, although their security against well-crafted attacks that aim to evade detection by manipulating data at test time has not yet been thoroughly assessed. While previous work has been mainly focused on devising adversary-aware classification algorithms to counter evasion attempts, only few authors have considered the impact of using reduced feature sets on classifier security against the same attacks. An interesting, preliminary result is that classifier security to evasion may be even worsened by the application of feature selection. In this paper, we provide a more detailed investigation of this aspect, shedding some light on the security properties of feature selection against evasion attacks. Inspired by previous work on adversary-aware classifiers, we propose a novel adversary-aware feature selection model that can improve classifier security against evasion attacks, by incorporating specific assumptions on the adversary's data manipulation strategy. We focus on an efficient, wrapper-based implementation of our approach, and experimentally validate its soundness on different application examples, including spam and malware detection.

Complement evasion by Bordetella pertussis: implications for improving current vaccines.

PubMed

Jongerius, Ilse; Schuijt, Tim J; Mooi, Frits R; Pinelli, Elena

2015-04-01

Bordetella pertussis causes whooping cough or pertussis, a highly contagious disease of the respiratory tract. Despite high vaccination coverage, reported cases of pertussis are rising worldwide and it has become clear that the current vaccines must be improved. In addition to the well-known protective role of antibodies and T cells during B. pertussis infection, innate immune responses such as the complement system play an essential role in B. pertussis killing. In order to evade this complement activation and colonize the human host, B. pertussis expresses several molecules that inhibit complement activation. Interestingly, one of the known complement evasion proteins, autotransporter Vag8, is highly expressed in the recently emerged B. pertussis isolates. Here, we describe the current knowledge on how B. pertussis evades complement-mediated killing. In addition, we compare this to complement evasion strategies used by other bacterial species. Finally, we discuss the consequences of complement evasion by B. pertussis on adaptive immunity and how identification of the bacterial molecules and the mechanisms involved in complement evasion might help improve pertussis vaccines.

Functional motifs responsible for human metapneumovirus M2-2-mediated innate immune evasion.

PubMed

Chen, Yu; Deng, Xiaoling; Deng, Junfang; Zhou, Jiehua; Ren, Yuping; Liu, Shengxuan; Prusak, Deborah J; Wood, Thomas G; Bao, Xiaoyong

2016-12-01

Human metapneumovirus (hMPV) is a major cause of lower respiratory infection in young children. Repeated infections occur throughout life, but its immune evasion mechanisms are largely unknown. We recently found that hMPV M2-2 protein elicits immune evasion by targeting mitochondrial antiviral-signaling protein (MAVS), an antiviral signaling molecule. However, the molecular mechanisms underlying such inhibition are not known. Our mutagenesis studies revealed that PDZ-binding motifs, 29-DEMI-32 and 39-KEALSDGI-46, located in an immune inhibitory region of M2-2, are responsible for M2-2-mediated immune evasion. We also found both motifs prevent TRAF5 and TRAF6, the MAVS downstream adaptors, to be recruited to MAVS, while the motif 39-KEALSDGI-46 also blocks TRAF3 migrating to MAVS. In parallel, these TRAFs are important in activating transcription factors NF-kB and/or IRF-3 by hMPV. Our findings collectively demonstrate that M2-2 uses its PDZ motifs to launch the hMPV immune evasion through blocking the interaction of MAVS and its downstream TRAFs. Copyright © 2016 Elsevier Inc. All rights reserved.

14 CFR 23.61 - Takeoff flight path.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Takeoff flight path. 23.61 Section 23.61... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Performance § 23.61 Takeoff flight path. For normal, utility, and acrobatic category multiengine jets of more than 6,000 pounds...

Conservation of a unique mechanism of immune evasion across the Lyssavirus genus.

PubMed

Wiltzer, L; Larrous, F; Oksayan, S; Ito, N; Marsh, G A; Wang, L F; Blondel, D; Bourhy, H; Jans, D A; Moseley, G W

2012-09-01

The evasion of host innate immunity by Rabies virus, the prototype of the genus Lyssavirus, depends on a unique mechanism of selective targeting of interferon-activated STAT proteins by the viral phosphoprotein (P-protein). However, the immune evasion strategies of other lyssaviruses, including several lethal human pathogens, are unresolved. Here, we show that this mechanism is conserved between the most distantly related members of the genus, providing important insights into the pathogenesis and potential therapeutic targeting of lyssaviruses.

Conservation of a Unique Mechanism of Immune Evasion across the Lyssavirus Genus

PubMed Central

Wiltzer, L.; Larrous, F.; Oksayan, S.; Ito, N.; Marsh, G. A.; Wang, L. F.; Blondel, D.; Bourhy, H.; Jans, D. A.

2012-01-01

The evasion of host innate immunity by Rabies virus, the prototype of the genus Lyssavirus, depends on a unique mechanism of selective targeting of interferon-activated STAT proteins by the viral phosphoprotein (P-protein). However, the immune evasion strategies of other lyssaviruses, including several lethal human pathogens, are unresolved. Here, we show that this mechanism is conserved between the most distantly related members of the genus, providing important insights into the pathogenesis and potential therapeutic targeting of lyssaviruses. PMID:22740405

15 CFR 760.4 - Evasion.

Code of Federal Regulations, 2010 CFR

2010-01-01

... justification unrelated to the boycott for changing the annual report in this fashion, A's action constitutes... of credit in the face of its knowledge of B's action constitutes evasion of this part, because A's...

15 CFR 760.4 - Evasion.

Code of Federal Regulations, 2011 CFR

2011-01-01

... justification unrelated to the boycott for changing the annual report in this fashion, A's action constitutes... of credit in the face of its knowledge of B's action constitutes evasion of this part, because A's...

Learning to Detect Deception from Evasive Answers and Inconsistencies across Repeated Interviews: A Study with Lay Respondents and Police Officers

PubMed Central

Masip, Jaume; Martínez, Carmen; Blandón-Gitlin, Iris; Sánchez, Nuria; Herrero, Carmen; Ibabe, Izaskun

2018-01-01

Previous research has shown that inconsistencies across repeated interviews do not indicate deception because liars deliberately tend to repeat the same story. However, when a strategic interview approach that makes it difficult for liars to use the repeat strategy is used, both consistency and evasive answers differ significantly between truth tellers and liars, and statistical software (binary logistic regression analyses) can reach high classification rates (Masip et al., 2016b). Yet, if the interview procedure is to be used in applied settings the decision process will be made by humans, not statistical software. To address this issue, in the current study, 475 college students (Experiment 1) and 142 police officers (Experiment 2) were instructed to code and use consistency, evasive answers, or a combination or both before judging the veracity of Masip et al.'s (2016b) interview transcripts. Accuracy rates were high (60% to over 90%). Evasive answers yielded higher rates than consistency, and the combination of both these cues produced the highest accuracy rates in identifying both truthful and deceptive statements. Uninstructed participants performed fairly well (around 75% accuracy), apparently because they spontaneously used consistency and evasive answers. The pattern of results was the same among students, all officers, and veteran officers only, and shows that inconsistencies between interviews and evasive answers reveal deception when a strategic interview approach that hinders the repeat strategy is used. PMID:29354078

The Missing Link in Epstein-Barr Virus Immune Evasion: the BDLF3 Gene Induces Ubiquitination and Downregulation of Major Histocompatibility Complex Class I (MHC-I) and MHC-II

PubMed Central

Quinn, Laura L.; Williams, Luke R.; White, Claire; Forrest, Calum; Rowe, Martin

2015-01-01

ABSTRACT The ability of Epstein-Barr virus (EBV) to spread and persist in human populations relies on a balance between host immune responses and EBV immune evasion. CD8+ cells specific for EBV late lytic cycle antigens show poor recognition of target cells compared to immediate early and early antigen-specific CD8+ cells. This phenomenon is due in part to the early EBV protein BILF1, whose immunosuppressive activity increases with lytic cycle progression. However, published data suggest the existence of a hitherto unidentified immune evasion protein further enhancing protection against late EBV antigen-specific CD8+ cells. We have now identified the late lytic BDLF3 gene as the missing link accounting for efficient evasion during the late lytic cycle. Interestingly, BDLF3 also contributes to evasion of CD4+ cell responses to EBV. We report that BDLF3 downregulates expression of surface major histocompatibility complex (MHC) class I and class II molecules in the absence of any effect upon other surface molecules screened, including CD54 (ICAM-1) and CD71 (transferrin receptor). BDLF3 both enhanced internalization of surface MHC molecules and reduced the rate of their appearance at the cell surface. The reduced expression of surface MHC molecules correlated with functional protection against CD8+ and CD4+ T cell recognition. The molecular mechanism was identified as BDLF3-induced ubiquitination of MHC molecules and their subsequent downregulation in a proteasome-dependent manner. IMPORTANCE Immune evasion is a necessary feature of viruses that establish lifelong persistent infections in the face of strong immune responses. EBV is an important human pathogen whose immune evasion mechanisms are only partly understood. Of the EBV immune evasion mechanisms identified to date, none could explain why CD8+ T cell responses to late lytic cycle genes are so infrequent and, when present, recognize lytically infected target cells so poorly relative to CD8+ T cells specific for early lytic cycle antigens. The present work identifies an additional immune evasion protein, BDLF3, that is expressed late in the lytic cycle and impairs CD8+ T cell recognition by targeting cell surface MHC class I molecules for ubiquitination and proteasome-dependent downregulation. Interestingly, BDLF3 also targets MHC class II molecules to impair CD4+ T cell recognition. BDLF3 is therefore a rare example of a viral protein that impairs both the MHC class I and class II antigen-presenting pathways. PMID:26468525

The Missing Link in Epstein-Barr Virus Immune Evasion: the BDLF3 Gene Induces Ubiquitination and Downregulation of Major Histocompatibility Complex Class I (MHC-I) and MHC-II.

PubMed

Quinn, Laura L; Williams, Luke R; White, Claire; Forrest, Calum; Zuo, Jianmin; Rowe, Martin

2016-01-01

The ability of Epstein-Barr virus (EBV) to spread and persist in human populations relies on a balance between host immune responses and EBV immune evasion. CD8(+) cells specific for EBV late lytic cycle antigens show poor recognition of target cells compared to immediate early and early antigen-specific CD8(+) cells. This phenomenon is due in part to the early EBV protein BILF1, whose immunosuppressive activity increases with lytic cycle progression. However, published data suggest the existence of a hitherto unidentified immune evasion protein further enhancing protection against late EBV antigen-specific CD8(+) cells. We have now identified the late lytic BDLF3 gene as the missing link accounting for efficient evasion during the late lytic cycle. Interestingly, BDLF3 also contributes to evasion of CD4(+) cell responses to EBV. We report that BDLF3 downregulates expression of surface major histocompatibility complex (MHC) class I and class II molecules in the absence of any effect upon other surface molecules screened, including CD54 (ICAM-1) and CD71 (transferrin receptor). BDLF3 both enhanced internalization of surface MHC molecules and reduced the rate of their appearance at the cell surface. The reduced expression of surface MHC molecules correlated with functional protection against CD8(+) and CD4(+) T cell recognition. The molecular mechanism was identified as BDLF3-induced ubiquitination of MHC molecules and their subsequent downregulation in a proteasome-dependent manner. Immune evasion is a necessary feature of viruses that establish lifelong persistent infections in the face of strong immune responses. EBV is an important human pathogen whose immune evasion mechanisms are only partly understood. Of the EBV immune evasion mechanisms identified to date, none could explain why CD8(+) T cell responses to late lytic cycle genes are so infrequent and, when present, recognize lytically infected target cells so poorly relative to CD8(+) T cells specific for early lytic cycle antigens. The present work identifies an additional immune evasion protein, BDLF3, that is expressed late in the lytic cycle and impairs CD8(+) T cell recognition by targeting cell surface MHC class I molecules for ubiquitination and proteasome-dependent downregulation. Interestingly, BDLF3 also targets MHC class II molecules to impair CD4(+) T cell recognition. BDLF3 is therefore a rare example of a viral protein that impairs both the MHC class I and class II antigen-presenting pathways. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Game and Information Theory Analysis of Electronic Counter Measures in Pursuit-Evasion Games

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffin, Christopher H

Two-player Pursuit-Evasion games in the literature typically either assume both players have perfect knowledge of the opponent s positions or use primitive sensing models. This unrealistically skews the problem in favor of the pursuer who need only maintain a faster velocity at all turning radii. In real life, an evader usually escapes when the pursuer no longer knows the evader s position. In our previous work, we modeled pursuit-evasion without perfect information as a two-player bi-matrix game by using a realistic sensor model and information theory to compute game theoretic payoff matrices. That game has a saddle point when themore » evader uses strategies that exploit sensor limitations, while the pursuer relies on strategies that ignore the sensing limitations. In this paper, we consider for the first time the effect of many types of electronic counter measures (ECM) on pursuit evasion games. The evader s decision to initiate its ECM is modeled as a function of the distance between the players. Simulations show how to find optimal strategies for ECM use when initial conditions are known. We also discuss the effectiveness of different ECM technologies in pursuit-evasion games.« less

Stereoscopic filming for investigating evasive side-stepping and anterior cruciate ligament injury risk

NASA Astrophysics Data System (ADS)

Lee, Marcus J. C.; Bourke, Paul; Alderson, Jacqueline A.; Lloyd, David G.; Lay, Brendan

2010-02-01

Non-contact anterior cruciate ligament (ACL) injuries are serious and debilitating, often resulting from the performance of evasive sides-stepping (Ssg) by team sport athletes. Previous laboratory based investigations of evasive Ssg have used generic visual stimuli to simulate realistic time and space constraints that athletes experience in the preparation and execution of the manoeuvre. However, the use of unrealistic visual stimuli to impose these constraints may not be accurately identifying the relationship between the perceptual demands and ACL loading during Ssg in actual game environments. We propose that stereoscopically filmed footage featuring sport specific opposing defender/s simulating a tackle on the viewer, when used as visual stimuli, could improve the ecological validity of laboratory based investigations of evasive Ssg. Due to the need for precision and not just the experience of viewing depth in these scenarios, a rigorous filming process built on key geometric considerations and equipment development to enable a separation of 6.5 cm between two commodity cameras had to be undertaken. Within safety limits, this could be an invaluable tool in enabling more accurate investigations of the associations between evasive Ssg and ACL injury risk.

26 CFR 1.269-1 - Meaning and use of terms.

Code of Federal Regulations, 2010 CFR

2010-04-01

... deduction, a credit, an adjustment, an exemption, or an exclusion. (b) Evasion or avoidance. The phrase evasion or avoidance is not limited to cases involving criminal penalties, or civil penalties for fraud...

Optimal feedback strategies for pursuit-evasion and interception in a plane

NASA Technical Reports Server (NTRS)

Rajan, N.; Ardema, M. D.

1983-01-01

Variable-speed pursuit-evasion and interception for two aircraft moving in a horizontal plane are analyzed in terms of a coordinate frame fixed in the plane at termination. Each participant's optimal motion can be represented by extremal trajectory maps. These maps are used to discuss sub-optimal approximations that are independent of the other participant. A method of constructing sections of the barrier, dispersal, and control-level surfaces and thus determining feedback strategies is described. Some examples are shown for pursuit-evasion and the minimum-time interception of a straight-flying target.

Man-vehicle systems research facility advanced aircraft flight simulator throttle mechanism

NASA Technical Reports Server (NTRS)

Kurasaki, S. S.; Vallotton, W. C.

1985-01-01

The Advanced Aircraft Flight Simulator is equipped with a motorized mechanism that simulates a two engine throttle control system that can be operated via a computer driven performance management system or manually by the pilots. The throttle control system incorporates features to simulate normal engine operations and thrust reverse and vary the force feel to meet a variety of research needs. While additional testing to integrate the work required is principally now in software design, since the mechanical aspects function correctly. The mechanism is an important part of the flight control system and provides the capability to conduct human factors research of flight crews with advanced aircraft systems under various flight conditions such as go arounds, coupled instrument flight rule approaches, normal and ground operations and emergencies that would or would not normally be experienced in actual flight.

Development goals in the post-2015 world: whither Canada?

PubMed

Labonté, Ronald

2014-05-29

A new set of post-2015 development goals for the world is being negotiated. Several potential goals relating to sustainable development, poverty, the economy and health have been identified. Many of them have potential public health gains, although there are inadequacies in how several of them have been defined. In participating in finalization of these goals, Canada should strengthen its commitments to maternal/child health; promote its publicly funded health system as an important model for universal health coverage; incorporate stronger protections for public health in trade and investment treaties; use its foreign aid to help low- and middle-income countries build the transparent and progressive tax systems to mobilize domestic revenues for health; and promote global systems of taxation to prevent tax evasion and illicit capital flight.

Infection, inflammation and host carbohydrates: A Glyco-Evasion Hypothesis

PubMed Central

Kreisman, Lori SC; Cobb, Brian A

2012-01-01

Microbial immune evasion can be achieved through the expression, or mimicry, of host-like carbohydrates on the microbial cell surface to hide from detection. However, disparate reports collectively suggest that evasion could also be accomplished through the modulation of the host glycosylation pathways, a mechanism that we call the “Glyco-Evasion Hypothesis”. Here, we will summarize the evidence in support of this paradigm by reviewing three separate bodies of work present in the literature. We review how infection and inflammation can lead to host glycosylation changes, how host glycosylation changes can increase susceptibility to infection and inflammation and how glycosylation impacts molecular and cellular function. Then, using these data as a foundation, we propose a unifying hypothesis in which microbial products can hijack host glycosylation to manipulate the immune response to the advantage of the pathogen. This model reveals areas of research that we believe could significantly improve our fight against infectious disease. PMID:22492234

Complement and innate immune evasion strategies of the human pathogenic fungus Candida albicans.

PubMed

Luo, Shanshan; Skerka, Christine; Kurzai, Oliver; Zipfel, Peter F

2013-12-15

Candida albicans is a medically important fungus that can cause a wide range of diseases ranging from superficial infections to disseminated disease, which manifests primarily in immuno-compromised individuals. Despite the currently applied anti-fungal therapies, both mortality and morbidity caused by this human pathogenic fungus are still unacceptably high. Therefore new prophylactic and therapeutic strategies are urgently needed to prevent fungal infection. In order to define new targets for combating fungal disease, there is a need to understand the immune evasion strategies of C. albicans in detail. In this review, we summarize different sophisticated immune evasion strategies that are utilized by C. albicans. The description of the molecular mechanisms used for immune evasion does on one hand help to understand the infection process, and on the other hand provides valuable information to define new strategies and diagnostic approaches to fight and interfere with Candida infections. Copyright © 2013 Elsevier Ltd. All rights reserved.

Novel Evasion Mechanisms of the Classical Complement Pathway

PubMed Central

Garcia, Brandon L.; Zwarthoff, Seline A.; Rooijakkers, Suzan H. M.; Geisbrecht, Brian V.

2016-01-01

Complement is a network of soluble and cell surface-associated proteins which gives rise to a self-amplifying, yet tightly regulated system with fundamental roles in immune surveillance and clearance. Complement becomes activated on the surface of ‘non-self’ cells by one of three initiating mechanisms known as the classical, lectin, or alternative pathways. Evasion of complement function is a hallmark of invasive pathogens and hematophagous organisms. While many complement inhibition strategies hinge on hijacking activities of endogenous complement regulatory proteins, an increasing number of uniquely evolved evasion molecules have been discovered over the past decade. In this review we focus on several recent investigations which have revealed mechanistically distinct inhibitors of the classical pathway. Because the classical pathway is an important and specific mediator of various autoimmune and inflammatory disorders, in-depth knowledge of novel evasion mechanisms could direct future development of therapeutic anti-inflammatory molecules. PMID:27591336

Novel Evasion Mechanisms of the Classical Complement Pathway.

PubMed

Garcia, Brandon L; Zwarthoff, Seline A; Rooijakkers, Suzan H M; Geisbrecht, Brian V

2016-09-15

Complement is a network of soluble and cell surface-associated proteins that gives rise to a self-amplifying, yet tightly regulated system with fundamental roles in immune surveillance and clearance. Complement becomes activated on the surface of nonself cells by one of three initiating mechanisms known as the classical, lectin, and alternative pathways. Evasion of complement function is a hallmark of invasive pathogens and hematophagous organisms. Although many complement-inhibition strategies hinge on hijacking activities of endogenous complement regulatory proteins, an increasing number of uniquely evolved evasion molecules have been discovered over the past decade. In this review, we focus on several recent investigations that revealed mechanistically distinct inhibitors of the classical pathway. Because the classical pathway is an important and specific mediator of various autoimmune and inflammatory disorders, in-depth knowledge of novel evasion mechanisms could direct future development of therapeutic anti-inflammatory molecules. Copyright © 2016 by The American Association of Immunologists, Inc.

Improving flight condition situational awareness through Human Centered Design.

PubMed

Craig, Carol

2012-01-01

In aviation, there is currently a lack of accurate and timely situational information, specifically weather data, which is essential when dealing with the unpredictable complexities that can arise while flying. For example, weather conditions that require immediate evasive action by the flight crew, such as isolated heavy rain, micro bursts, and atmospheric turbulence, require that the flight crew receive near real-time and precise information about the type, position, and intensity of those conditions. Human factors issues arise in considering how to display the various sources of weather information to the users of that information and how to integrate this display into the existing environment. In designing weather information display systems, it is necessary to meet the demands of different users, which requires an examination of the way in which the users process and use weather information. Using Human Centered Design methodologies and concepts will result in a safer, more efficient and more intuitive solution. Specific goals of this approach include 1) Enabling better fuel planning; 2) Allowing better divert strategies; 3) Ensuring pilots, navigators, dispatchers and mission planners are referencing weather from the same sources; 4) Improving aircrew awareness of aviation hazards such as turbulence, icing, hail and convective activity; 5) Addressing inconsistent availability of hazard forecasts outside the United States Air Defense Identification Zone (ADIZ); and 6) Promoting goal driven approaches versus event driven (prediction).

Behavioral responses of big brown bats to dives by praying mantises

PubMed Central

Ghose, Kaushik; Triblehorn, Jeffrey D.; Bohn, Kari; Yager, David D.; Moss, Cynthia F.

2009-01-01

Summary Insectivorous echolocating bats face a formidable array of defenses employed by their airborne prey. One such insect defense is the ultrasound-triggered dive, which is a sudden, rapid drop in altitude, sometimes all the way to the ground. Although many previous studies have investigated the dynamics of such dives and their effect on insect survival rate, there has been little work on how bats may adapt to such an insect defense employed in the middle of pursuit. In this study we investigated how big brown bats (Eptesicus fuscus) adjust their pursuit strategy when flying praying mantises (Parasphendale agrionina) execute evasive, ultrasound-triggered dives. Although the mantis dive occasionally forced the bat to completely abort its chase (25% trials), in a number of cases (75% trials) the bat followed the mantis into the dive. In such cases the bat kept its sonar beam locked onto the target and maneuvered to maintain the same time efficient strategy it adopted during level flight pursuit, though it was ultimately defeated by the dive. This study suggests that although the mantis dive can be effective in evading the bat, it does not always deter the bat from continuing pursuit and, given enough altitude, the bat can potentially capture diving prey using the same flight strategy it employs to intercept prey in level flight. PMID:19218521

Evasion of adaptive and innate immune response mechanisms by γ-herpesviruses

PubMed Central

Feng, Pinghui; Moses, Ashlee; Früh, Klaus

2015-01-01

γ-Herpesviral immune evasion mechanisms are optimized to support the acute, lytic and the longterm, latent phase of infection. During acute infection, specific immune modulatory proteins limit, but also exploit, the antiviral activities of cell intrinsic innate immune responses as well as those of innate and adaptive immune cells. During latent infection, a restricted gene expression program limits immune targeting and cis-acting mechanisms to reduce the antigen presentation as well as antigenicity of latency-associated proteins. Here, we will review recent progress in our understanding of γ-herpesviral immune evasion strategies. PMID:23735334

Complex pattern of immune evasion in MSI colorectal cancer.

PubMed

Ozcan, Mine; Janikovits, Jonas; von Knebel Doeberitz, Magnus; Kloor, Matthias

2018-01-01

Mismatch repair (MMR)-deficient cancers accumulate multiple insertion/deletion mutations at coding microsatellites (cMS), which give rise to frameshift peptide neoantigens. The high mutational neoantigen load of MMR-deficient cancers is reflected by pronounced anti-tumoral immune responses of the host and high responsiveness towards immune checkpoint blockade. However, immune evasion mechanisms can interfere with the immune response against MMR-deficient tumors. We here performed a comprehensive analysis of immune evasion in MMR-deficient colorectal cancers, focusing on HLA class I-mediated antigen presentation. 72% of MMR-deficient colorectal cancers of the DFCI database harbored alterations affecting genes involved in HLA class I-mediated antigen presentation, and 54% of these mutations were predicted to abrogate function. Mutations affecting the HLA class I transactivator NLRC5 were observed as a potential new immune evasion mechanism in 26% (6% abrogating) of the analyzed tumors. NLRC5 mutations in MMR-deficient cancers were associated with decreased levels of HLA class I antigen expression. In summary, the majority of MMR-deficient cancers display mutations interfering with HLA class I antigen presentation that reflect active immune surveillance and immunoselection during tumor development. Clinical studies focusing on immune checkpoint blockade in MSI cancer should account for the broad variety of immune evasion mechanisms as potential biomarkers of therapy success.

Evasion of Neutrophil Extracellular Traps by Respiratory Pathogens.

PubMed

Storisteanu, Daniel M L; Pocock, Joanna M; Cowburn, Andrew S; Juss, Jatinder K; Nadesalingam, Angalee; Nizet, Victor; Chilvers, Edwin R

2017-04-01

The release of neutrophil extracellular traps (NETs) is a major immune mechanism intended to capture pathogens. These histone- and protease-coated DNA structures are released by neutrophils in response to a variety of stimuli, including respiratory pathogens, and have been identified in the airways of patients with respiratory infection, cystic fibrosis, acute lung injury, primary graft dysfunction, and chronic obstructive pulmonary disease. NET production has been demonstrated in the lungs of mice infected with Staphylococcus aureus, Klebsiella pneumoniae, and Aspergillus fumigatus. Since the discovery of NETs over a decade ago, evidence that "NET evasion" might act as an immune protection strategy among respiratory pathogens, including group A Streptococcus, Bordetella pertussis, and Haemophilus influenzae, has been growing, with the majority of these studies being published in the past 2 years. Evasion strategies fall into three main categories: inhibition of NET release by down-regulating host inflammatory responses; degradation of NETs using pathogen-derived DNases; and resistance to the microbicidal components of NETs, which involves a variety of mechanisms, including encapsulation. Hence, the evasion of NETs appears to be a widespread strategy to allow pathogen proliferation and dissemination, and is currently a topic of intense research interest. This article outlines the evidence supporting the three main strategies of NET evasion-inhibition, degradation, and resistance-with particular reference to common respiratory pathogens.

Cross-border reproductive care for law evasion: should physicians be allowed to help infertility patients evade the law of their own country?

PubMed

Van Hoof, Wannes; Pennings, Guido; De Sutter, Petra

2016-07-01

There are fundamental differences between countries with regard to legislation on assisted reproduction. Many infertility patients are looking to evade the law of their own country and make use of reproductive services abroad. The role of the local physician in cross-border reproductive care for law evasion has been characterized as "channeling local patients to foreign medical establishments" and "against the spirit and essence of the law". The logical view is that by supporting CBRC for law evasion, physicians are essentially supporting immoral behavior. We will tackle this position on two levels. First, we will argue that governments should generally be tolerant toward people with different positions on assisted reproduction. Second, we will show that contributing to cross-border reproductive care for law evasion is not necessarily immoral, because the prima facie wrongness of complicity in law evasion can be outweighed by the fact that physicians should act in the best interest of the patient. Several countries have tried to prevent local physicians from helping patients to make use of reproductive services abroad, but they should rather leave it up to the individual physicians to decide whether or not to support a particular patient. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Evaluation of the Hinge Moment and Normal Force Aerodynamic Loads from a Seamless Adaptive Compliant Trailing Edge Flap in Flight

NASA Technical Reports Server (NTRS)

Miller, Eric J.; Cruz, Josue; Lung, Shun-Fat; Kota, Sridhar; Ervin, Gregory; Lu, Kerr-Jia; Flick, Pete

2016-01-01

A seamless adaptive compliant trailing edge (ACTE) flap was demonstrated in flight on a Gulfstream III aircraft at the NASA Armstrong Flight Research Center. The trailing edge flap was deflected between minus 2 deg up and plus 30 deg down in flight. The safety-of-flight parameters for the ACTE flap experiment require that flap-to-wing interface loads be sensed and monitored in real time to ensure that the structural load limits of the wing are not exceeded. The attachment fittings connecting the flap to the aircraft wing rear spar were instrumented with strain gages and calibrated using known loads for measuring hinge moment and normal force loads in flight. The safety-of-flight parameters for the ACTE flap experiment require that flap-to-wing interface loads be sensed and monitored in real time to ensure that the structural load limits of the wing are not exceeded. The attachment fittings connecting the flap to the aircraft wing rear spar were instrumented with strain gages and calibrated using known loads for measuring hinge moment and normal force loads in flight. The interface hardware instrumentation layout and load calibration are discussed. Twenty-one applied calibration test load cases were developed for each individual fitting. The 2-sigma residual errors for the hinge moment was calculated to be 2.4 percent, and for normal force was calculated to be 7.3 percent. The hinge moment and normal force generated by the ACTE flap with a hinge point located at 26-percent wing chord were measured during steady state and symmetric pitch maneuvers. The loads predicted from analysis were compared to the loads observed in flight. The hinge moment loads showed good agreement with the flight loads while the normal force loads calculated from analysis were over-predicted by approximately 20 percent. Normal force and hinge moment loads calculated from the pressure sensors located on the ACTE showed good agreement with the loads calculated from the installed strain gages.

Fine-tuned echolocation and capture-flight of Myotis capaccinii when facing different-sized insect and fish prey.

PubMed

Aizpurua, Ostaizka; Aihartza, Joxerra; Alberdi, Antton; Baagøe, Hans J; Garin, Inazio

2014-09-15

Formerly thought to be a strictly insectivorous trawling bat, recent studies have shown that Myotis capaccinii also preys on fish. To determine whether differences exist in bat flight behaviour, prey handling and echolocation characteristics when catching fish and insects of different size, we conducted a field experiment focused on the last stage of prey capture. We used synchronized video and ultrasound recordings to measure several flight and dip features as well as echolocation characteristics, focusing on terminal buzz phase I, characterized by a call rate exceeding 100 Hz, and buzz phase II, characterized by a drop in the fundamental well below 20 kHz and a repetition rate exceeding 150 Hz. When capturing insects, bats used both parts of the terminal phase to the same extent, and performed short and superficial drags on the water surface. In contrast, when preying on fish, buzz I was longer and buzz II shorter, and the bats made longer and deeper dips. These variations suggest that lengthening buzz I and shortening buzz II when fishing is beneficial, probably because buzz I gives better discrimination ability and the broader sonar beam provided by buzz II is useless when no evasive flight of the prey is expected. Additionally, bats continued emitting calls beyond the theoretical signal-overlap zone, suggesting that they might obtain information even when they have surpassed that threshold, at least initially. This study shows that M. capaccinii can regulate the temporal components of its feeding buzzes and modify prey capture technique according to the target. © 2014. Published by The Company of Biologists Ltd.

Opportunities for nutritional amelioration of radiation-induced cellular damage

NASA Technical Reports Server (NTRS)

Turner, Nancy D.; Braby, Leslie A.; Ford, John; Lupton, Joanne R.

2002-01-01

The closed environment and limited evasive capabilities inherent in space flight cause astronauts to be exposed to many potential harmful agents (chemical contaminants in the environment and cosmic radiation exposure). Current power systems used to achieve space flight are prohibitively expensive for supporting the weight requirements to fully shield astronauts from cosmic radiation. Therefore, radiation poses a major, currently unresolvable risk for astronauts, especially for long-duration space flights. The major detrimental radiation effects that are of primary concern for long-duration space flights are damage to the lens of the eye, damage to the immune system, damage to the central nervous system, and cancer. In addition to the direct damage to biological molecules in cells, radiation exposure induces oxidative damage. Many natural antioxidants, whether consumed before or after radiation exposure, are able to confer some level of radioprotection. In addition to achieving beneficial effects from long-known antioxidants such as vitamins E and C and folic acid, some protection is conferred by several recently discovered antioxidant molecules, such as flavonoids, epigallocatechin, and other polyphenols. Somewhat counterintuitive is the protection provided by diets containing elevated levels of omega-3 polyunsaturated fatty acids, considering they are thought to be prone to peroxidation. Even with the information we have at our disposal, it will be difficult to predict the types of dietary modifications that can best reduce the risk of radiation exposure to astronauts, those living on Earth, or those enduring diagnostic or therapeutic radiation exposure. Much more work must be done in humans, whether on Earth or, preferably, in space, before we are able to make concrete recommendations.

15 CFR Supplement No. 12 to Part 760 - Interpretation

Code of Federal Regulations, 2010 CFR

2010-01-01

... § 760.2(d) of this part. Example (v) under § 760.4 of this part (Evasion) provides: “A, a U.S. company... to supply the necessary information.” “A's action constitutes evasion of this part, because it is a...

The air-sea exchange of mercury in the low latitude Pacific and Atlantic Oceans

NASA Astrophysics Data System (ADS)

Mason, Robert P.; Hammerschmidt, Chad R.; Lamborg, Carl H.; Bowman, Katlin L.; Swarr, Gretchen J.; Shelley, Rachel U.

2017-04-01

Air-sea exchange is an important component of the global mercury (Hg) cycle as it mediates the rate of increase in ocean Hg, and therefore the rate of change in levels of methylmercury (MeHg), the most toxic and bioaccumulative form of Hg in seafood and the driver of human health concerns. Gas evasion of elemental Hg (Hg0) from the ocean is an important sink for ocean Hg with previous studies suggesting that evasion is not uniform across ocean basins. To understand further the factors controlling Hg0 evasion, and its relationship to atmospheric Hg deposition, we made measurements of dissolved Hg0 (DHg0) in surface waters, along with measurements of Hg in precipitation and on aerosols, and Hg0 in marine air, during two GEOTRACES cruises; GP16 in the equatorial South Pacific and GA03 in the North Atlantic. We contrast the concentrations and estimated evasion fluxes of Hg0 during these cruises, and the factors influencing this exchange. Concentrations of DHg0 and fluxes were lower during the GP16 cruise than during the GA03 cruise, and likely reflect the lower atmospheric deposition in the South Pacific. An examination of Hg/Al ratios for aerosols from the cruises suggests that they were anthropogenically-enriched relative to crustal material, although to a lesser degree for the South Pacific than the aerosols over the North Atlantic. Both regions appear to be net sources of Hg0 to the atmosphere (evasion>deposition) and the reasons for this are discussed. Overall, the studies reported here provide further clarification on the factors controlling evasion of Hg0 from the ocean surface, and the role of anthropogenic inputs in influencing ocean Hg concentrations.

Staphylococcus aureus innate immune evasion is lineage-specific: a bioinfomatics study.

PubMed

McCarthy, Alex J; Lindsay, Jodi A

2013-10-01

Staphylococcus aureus is a major human pathogen, and is targeted by the host innate immune system. In response, S. aureus genomes encode dozens of secreted proteins that inhibit complement, chemotaxis and neutrophil activation resulting in successful evasion of innate immune responses. These proteins include immune evasion cluster proteins (IEC; Chp, Sak, Scn), staphylococcal superantigen-like proteins (SSLs), phenol soluble modulins (PSMs) and several leukocidins. Biochemical studies have indicated that genetic variants of these proteins can have unique functions. To ascertain the scale of genetic variation in secreted immune evasion proteins, whole genome sequences of 88 S. aureus isolates, representing 25 clonal complex (CC) lineages, in the public domain were analysed across 43 genes encoding 38 secreted innate immune evasion protein complexes. Twenty-three genes were variable, with between 2 and 15 variants, and the variants had lineage-specific distributions. They include genes encoding Eap, Ecb, Efb, Flipr/Flipr-like, Hla, Hld, Hlg, Sbi, Scin-B/C and 13 SSLs. Most of these protein complexes inhibit complement, chemotaxis and neutrophil activation suggesting that isolates from each S. aureus lineage respond to the innate immune system differently. In contrast, protein complexes that lyse neutrophils (LukSF-PVL, LukMF, LukED and PSMs) were highly conserved, but can be carried on mobile genetic elements (MGEs). MGEs also encode proteins with narrow host-specificities arguing that their acquisition has important roles in host/environmental adaptation. In conclusion, this data suggests that each lineage of S. aureus evades host immune responses differently, and that isolates can adapt to new host environments by acquiring MGEs and the immune evasion protein complexes that they encode. Cocktail therapeutics that targets multiple variant proteins may be the most appropriate strategy for controlling S. aureus infections. Copyright © 2013 Elsevier B.V. All rights reserved.

14 CFR 121.915 - Continuing qualification curriculum.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., flight training device, flight simulator, or other equipment, as appropriate, on normal, abnormal, and... training in the type flight training device or the type flight simulator, as appropriate, regarding... flight simulators or flight training devices: Training in operational flight procedures and maneuvers...

14 CFR 121.915 - Continuing qualification curriculum.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., flight training device, flight simulator, or other equipment, as appropriate, on normal, abnormal, and... training in the type flight training device or the type flight simulator, as appropriate, regarding... flight simulators or flight training devices: Training in operational flight procedures and maneuvers...

14 CFR 121.915 - Continuing qualification curriculum.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., flight training device, flight simulator, or other equipment, as appropriate, on normal, abnormal, and... training in the type flight training device or the type flight simulator, as appropriate, regarding... flight simulators or flight training devices: Training in operational flight procedures and maneuvers...

31 CFR 592.202 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Evasions; attempts; conspiracies. 592.202 Section 592.202 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS...

31 CFR 592.202 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Evasions; attempts; conspiracies. 592.202 Section 592.202 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS...

31 CFR 592.202 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Evasions; attempts; conspiracies. 592.202 Section 592.202 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS...

31 CFR 595.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 595.205 Section 595.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY TERRORISM SANCTIONS REGULATIONS Prohibitions...

31 CFR 594.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Evasions; attempts; conspiracies. 594.205 Section 594.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY GLOBAL TERRORISM SANCTIONS REGULATIONS...

31 CFR 594.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Evasions; attempts; conspiracies. 594.205 Section 594.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY GLOBAL TERRORISM SANCTIONS REGULATIONS...

31 CFR 594.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Evasions; attempts; conspiracies. 594.205 Section 594.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY GLOBAL TERRORISM SANCTIONS REGULATIONS...

31 CFR 546.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 546.205 Section 546.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY DARFUR SANCTIONS REGULATIONS Prohibitions...

31 CFR 538.211 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Evasions; attempts; conspiracies. 538.211 Section 538.211 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SUDANESE SANCTIONS REGULATIONS Prohibitions...

31 CFR 537.206 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Evasions; attempts; conspiracies. 537.206 Section 537.206 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BURMESE SANCTIONS REGULATIONS Prohibitions...

26 CFR 1.269-4 - Power of district director to allocate deduction, credit, or allowance in part.

Code of Federal Regulations, 2010 CFR

2010-04-01

... evasion or avoidance of Federal income tax for which the acquisition was made. The district director is...(a), but only to such extent as he determines will not result in the evasion or avoidance of Federal...

Conserved hypothetical protein Rv1977 in Mycobacterium tuberculosis strains contains sequence polymorphisms and might be involved in ongoing immune evasion.

PubMed

Jiang, Yi; Liu, Haican; Wang, Xuezhi; Li, Guilian; Qiu, Yan; Dou, Xiangfeng; Wan, Kanglin

2015-01-01

Host immune pressure and associated parasite immune evasion are key features of host-pathogen co-evolution. A previous study showed that human T cell epitopes of Mycobacterium tuberculosis are evolutionarily hyperconserved and thus it was deduced that M. tuberculosis lacks antigenic variation and immune evasion. Here, we selected 151 clinical Mycobacterium tuberculosis isolates from China, amplified gene encoding Rv1977 and compared the sequences. The results showed that Rv1977, a conserved hypothetical protein, is not conserved in M. tuberculosis strains and there are polymorphisms existed in the protein. Some mutations, especially one frameshift mutation, occurred in the antigen Rv1977, which is uncommon in M.tb strains and may lead to the protein function altering. Mutations and deletion in the gene all affect one of three T cell epitopes and the changed T cell epitope contained more than one variable position, which may suggest ongoing immune evasion.

Ignoring the irrelevant: auditory tolerance of audible but innocuous sounds in the bat-detecting ears of moths

NASA Astrophysics Data System (ADS)

Fullard, James H.; Ratcliffe, John M.; Jacobs, David S.

2008-03-01

Noctuid moths listen for the echolocation calls of hunting bats and respond to these predator cues with evasive flight. The African bollworm moth, Helicoverpa armigera, feeds at flowers near intensely singing cicadas, Platypleura capensis, yet does not avoid them. We determined that the moth can hear the cicada by observing that both of its auditory receptors (A1 and A2 cells) respond to the cicada’s song. The firing response of the A1 cell rapidly adapts to the song and develops spike periods in less than a second that are in excess of those reported to elicit avoidance flight to bats in earlier studies. The possibility also exists that for at least part of the day, sensory input in the form of olfaction or vision overrides the moth’s auditory responses. While auditory tolerance appears to allow H. armigera to exploit a food resource in close proximity to acoustic interference, it may render their hearing defence ineffective and make them vulnerable to predation by bats during the evening when cicadas continue to sing. Our study describes the first field observation of an eared insect ignoring audible but innocuous sounds.

Nonclassical Flight Control for Unhealthy Aircraft

NASA Technical Reports Server (NTRS)

Lu, Ping

1997-01-01

This research set out to investigate flight control of aircraft which has sustained damage in regular flight control effectors, due to jammed control surfaces or complete loss of hydraulic power. It is recognized that in such an extremely difficult situation unconventional measures may need to be taken to regain control and stability of the aircraft. Propulsion controlled aircraft (PCA) concept, initiated at the NASA Dryden Flight Research Center. represents a ground-breaking effort in this direction. In this approach, the engine is used as the only flight control effector in the rare event of complete loss of normal flight control system. Studies and flight testing conducted at NASA Dryden have confirmed the feasibility of the PCA concept. During the course of this research (March 98, 1997 to November 30, 1997), a comparative study has been done using the full nonlinear model of an F-18 aircraft. Linear controllers and nonlinear controllers based on a nonlinear predictive control method have been designed for normal flight control system and propulsion controlled aircraft. For the healthy aircraft with normal flight control, the study shows that an appropriately designed linear controller can perform as well as a nonlinear controller. On the other hand. when the normal flight control is lost and the engine is the only available means of flight control, a nonlinear PCA controller can significantly increase the size of the recoverable region in which the stability of the unstable aircraft can be attained by using only thrust modulation. The findings and controller design methods have been summarized in an invited paper entitled.

Quantifying Pilot Contribution to Flight Safety During Dual Generator Failure

NASA Technical Reports Server (NTRS)

Etherington, Timothy J.; Kramer, Lynda J.; Kennedy, Kellie D.; Bailey, Randall E.; Last, Mary Carolyn

2017-01-01

Accident statistics cite flight crew error in over 60% of accidents involving transport category aircraft. Yet, a well-trained and well-qualified pilot is acknowledged as the critical center point of aircraft systems safety and an integral safety component of the entire commercial aviation system. No data currently exists that quantifies the contribution of the flight crew in this role. Neither does data exist for how often the flight crew handles non-normal procedures or system failures on a daily basis in the National Airspace System. A pilot-in-the-loop high fidelity motion simulation study was conducted by the NASA Langley Research Center in partnership with the Federal Aviation Administration (FAA) to evaluate the pilot's contribution to flight safety during normal flight and in response to aircraft system failures. Eighteen crews flew various normal and non-normal procedures over a two-day period and their actions were recorded in response to failures. To quantify the human's contribution, crew complement was used as the experiment independent variable in a between-subjects design. Pilot actions and performance when one of the flight crew was unavailable were also recorded for comparison against the nominal two-crew operations. This paper details diversion decisions, perceived safety of flight, workload, time to complete pertinent checklists, and approach and landing results while dealing with a complete loss of electrical generators. Loss of electrical power requires pilots to complete the flight without automation support of autopilots, flight directors, or auto throttles. For reduced crew complements, the additional workload and perceived safety of flight was considered unacceptable.

Pulmonary function abnormalities in never-smoking flight attendants exposed to secondhand tobacco smoke in the aircraft cabin.

PubMed

Arjomandi, Mehrdad; Haight, Thaddeus; Redberg, Rita; Gold, Warren M

2009-06-01

To determine whether the flight attendants who were exposed to secondhand tobacco smoke in the aircraft cabin have abnormal pulmonary function. We administered questionnaires and performed pulmonary function testing in 61 never-smoking female flight attendants who worked in active air crews before the smoking ban on commercial aircraft (preban). Although the preban flight attendants had normal FVC, FEV1, and FEV1/FVC ratio, they had significantly decreased flow at mid- and low-lung volumes, curvilinear flow-volume curves, and evidence of air trapping. Furthermore, the flight attendants had significantly decreased diffusing capacity (77.5% +/- 11.2% predicted normal) with 51% having a diffusing capacity below their 95% normal prediction limit. This cohort of healthy never-smoking flight attendants who were exposed to secondhand tobacco smoke in the aircraft cabin showed pulmonary function abnormalities suggestive of airway obstruction and impaired diffusion.

Barriers and dispersal surfaces in minimum-time interception. [for optimizing aircraft flight paths

NASA Technical Reports Server (NTRS)

Rajan, N.; Ardema, M. D.

1984-01-01

A method is proposed for mapping the barrier, dispersal, and control-level surfaces for a class of minimum-time interception and pursuit-evasion problems. Minimum-time interception of a target moving in a horizontal plane is formulated in a coordinate system whose origin is at the interceptor's terminal position and whose x-axis is along the terminal line of sight. This approach makes it possible to discuss the nature of the interceptor's extremals, using its extremal trajectory maps (ETMs), independently of target motion. The game surfaces are constructed by drawing sections of the isochrones, or constant minimum-time loci, from the interceptor and target ETMs. In this way, feedback solutions for the optimal controls are obtained. An example involving the interception of a target moving in a straight line at constant speed is presented.

31 CFR 593.206 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Evasions; attempts; conspiracies. 593.206 Section 593.206 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FORMER LIBERIAN REGIME OF CHARLES TAYLOR...

31 CFR 593.206 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Evasions; attempts; conspiracies. 593.206 Section 593.206 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FORMER LIBERIAN REGIME OF CHARLES TAYLOR...

31 CFR 593.206 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Evasions; attempts; conspiracies. 593.206 Section 593.206 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FORMER LIBERIAN REGIME OF CHARLES TAYLOR...

31 CFR 593.206 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Evasions; attempts; conspiracies. 593.206 Section 593.206 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FORMER LIBERIAN REGIME OF CHARLES TAYLOR...

Planning and Assessing Stability Operations: A Proposed Value Focus Thinking Approach

DTIC Science & Technology

2007-03-01

to avoid double -counting of possible consequences. 8... Taxes War Profiteering Arms Smuggling Grey Economy Avoidance of taxes Violation of regulations Smuggling Evasion of economic embargoes... Taxes War Profiteering Arms Smuggling Grey Economy Avoidance of taxes Violation of regulations Smuggling Evasion of economic embargoes

31 CFR 547.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Evasions; attempts; conspiracies. 547.205 Section 547.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY DEMOCRATIC REPUBLIC OF THE CONGO SANCTIONS...

31 CFR 547.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Evasions; attempts; conspiracies. 547.205 Section 547.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY DEMOCRATIC REPUBLIC OF THE CONGO SANCTIONS...

31 CFR 547.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Evasions; attempts; conspiracies. 547.205 Section 547.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY DEMOCRATIC REPUBLIC OF THE CONGO SANCTIONS...

31 CFR 547.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Evasions; attempts; conspiracies. 547.205 Section 547.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY DEMOCRATIC REPUBLIC OF THE CONGO SANCTIONS...

31 CFR 547.205 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Evasions; attempts; conspiracies. 547.205 Section 547.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY DEMOCRATIC REPUBLIC OF THE CONGO SANCTIONS...

An update: Epstein-Barr virus and immune evasion via microRNA regulation.

PubMed

Zuo, Lielian; Yue, Wenxin; Du, Shujuan; Xin, Shuyu; Zhang, Jing; Liu, Lingzhi; Li, Guiyuan; Lu, Jianhong

2017-06-01

Epstein-Barr virus (EBV) is an oncogenic virus that ubiquitously establishes life-long persistence in humans. To ensure its survival and maintain its B cell transformation function, EBV has developed powerful strategies to evade host immune responses. Emerging evidence has shown that microRNAs (miRNAs) are powerful regulators of the maintenance of cellular homeostasis. In this review, we summarize current progress on how EBV utilizes miRNAs for immune evasion. EBV encodes miRNAs targeting both viral and host genes involved in the immune response. The miRNAs are found in two gene clusters, and recent studies have demonstrated that lack of these clusters increases the CD4 + and CD8 + T cell response of infected cells. These reports strongly indicate that EBV miRNAs are critical for immune evasion. In addition, EBV is able to dysregulate the expression of a variety of host miRNAs, which influence multiple immune-related molecules and signaling pathways. The transport via exosomes of EBV-regulated miRNAs and viral proteins contributes to the construction and modification of the inflammatory tumor microenvironment. During EBV immune evasion, viral proteins, immune cells, chemokines, pro-inflammatory cytokines, and pro-apoptosis molecules are involved. Our increasing knowledge of the role of miRNAs in immune evasion will improve the understanding of EBV persistence and help to develop new treatments for EBV-associated cancers and other diseases.

Immune evasion strategies of ranaviruses and innate immune responses to these emerging pathogens.

PubMed

Grayfer, Leon; Andino, Francisco De Jesús; Chen, Guangchun; Chinchar, Gregory V; Robert, Jacques

2012-07-01

Ranaviruses (RV, Iridoviridae) are large double-stranded DNA viruses that infect fish, amphibians and reptiles. For ecological and commercial reasons, considerable attention has been drawn to the increasing prevalence of ranaviral infections of wild populations and in aquacultural settings. Importantly, RVs appear to be capable of crossing species barriers of numerous poikilotherms, suggesting that these pathogens possess a broad host range and potent immune evasion mechanisms. Indeed, while some of the 95-100 predicted ranavirus genes encode putative evasion proteins (e.g., vIFα, vCARD), roughly two-thirds of them do not share significant sequence identity with known viral or eukaryotic genes. Accordingly, the investigation of ranaviral virulence and immune evasion strategies is promising for elucidating potential antiviral targets. In this regard, recombination-based technologies are being employed to knock out gene candidates in the best-characterized RV member, Frog Virus (FV3). Concurrently, by using animal infection models with extensively characterized immune systems, such as the African clawed frog, Xenopus laevis, it is becoming evident that components of innate immunity are at the forefront of virus-host interactions. For example, cells of the macrophage lineage represent important combatants of RV infections while themselves serving as targets for viral infection, maintenance and possibly dissemination. This review focuses on the recent advances in the understanding of the RV immune evasion strategies with emphasis on the roles of the innate immune system in ranaviral infections.

34 CFR 668.207 - Preventing evasion of the consequences of cohort default rates.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false Preventing evasion of the consequences of cohort default rates. 668.207 Section 668.207 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION STUDENT ASSISTANCE GENERAL PROVISIONS...

34 CFR 668.188 - Preventing evasion of the consequences of cohort default rates.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false Preventing evasion of the consequences of cohort default rates. 668.188 Section 668.188 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION STUDENT ASSISTANCE GENERAL PROVISIONS...

31 CFR 592.202 - Evasions; attempts; conspiracies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Prohibitions § 592.202 Evasions; attempts; conspiracies. (a) Notwithstanding the existence of any rights or... purpose of evading or avoiding, or attempts to violate, any of the prohibitions set forth in this part is prohibited. (b) Notwithstanding the existence of any rights or obligations conferred or imposed by any...

Role of Corticosteroids in Bone Loss During Space Flight

NASA Technical Reports Server (NTRS)

Wronski, Thomas J.; Halloran, Bernard P.; Miller, Scott C.

1998-01-01

The primary objective of this research project is to test the hypothesis that corticosteroids contribute to the adverse skeletal effects of space flight. To achieve this objective, serum corticosteroids, which are known to increase during space flight, must be maintained at normal physiologic levels in flight rats by a combination of adrenalectomy and corticosteroid supplementation via implanted hormone pellets. Bone analyses in these animals will then be compared to those of intact flight rats that, based on past experience, will undergo corticosteroid excess and bone loss during space flight. The results will reveal whether maintaining serum corticosteroids at physiologic levels in flight rats affects the skeletal abnormalities that normally develop during space flight. A positive response to this question would indicate that the bone loss and decreased bone formation associated with space flight are mediated, at least in part, by corticosteroid excess.

Quantifying Pilot Contribution to Flight Safety during Drive Shaft Failure

NASA Technical Reports Server (NTRS)

Kramer, Lynda J.; Etherington, Tim; Last, Mary Carolyn; Bailey, Randall E.; Kennedy, Kellie D.

2017-01-01

Accident statistics cite the flight crew as a causal factor in over 60% of large transport aircraft fatal accidents. Yet, a well-trained and well-qualified pilot is acknowledged as the critical center point of aircraft systems safety and an integral safety component of the entire commercial aviation system. The latter statement, while generally accepted, cannot be verified because little or no quantitative data exists on how and how many accidents/incidents are averted by crew actions. A joint NASA/FAA high-fidelity motion-base simulation experiment specifically addressed this void by collecting data to quantify the human (pilot) contribution to safety-of-flight and the methods they use in today's National Airspace System. A human-in-the-loop test was conducted using the FAA's Oklahoma City Flight Simulation Branch Level D-certified B-737-800 simulator to evaluate the pilot's contribution to safety-of-flight during routine air carrier flight operations and in response to aircraft system failures. These data are fundamental to and critical for the design and development of future increasingly autonomous systems that can better support the human in the cockpit. Eighteen U.S. airline crews flew various normal and non-normal procedures over a two-day period and their actions were recorded in response to failures. To quantify the human's contribution to safety of flight, crew complement was used as the experiment independent variable in a between-subjects design. Pilot actions and performance during single pilot and reduced crew operations were measured for comparison against the normal two-crew complement during normal and non-normal situations. This paper details the crew's actions, including decision-making, and responses while dealing with a drive shaft failure - one of 6 non-normal events that were simulated in this experiment.

Avoiding evasion: medical ethics education and emotion theory.

PubMed

Leget, C

2004-10-01

Beginning with an exemplary case study, this paper diagnoses and analyses some important strategies of evasion and factors of hindrance that are met in the teaching of medical ethics to undergraduate medical students. Some of these inhibitions are inherent to ethical theories; others are connected with the nature of medicine or cultural trends. It is argued that in order to avoid an attitude of evasion in medical ethics teaching, a philosophical theory of emotions is needed that is able to clarify on a conceptual level the ethical importance of emotions. An approach is proposed with the help of the emotion theory Martha Nussbaum works out in her book Upheavals of thought. The paper ends with some practical recommendations.

The Production of lnterleukin-1 Receptor Antagonist by Human Bronchogenic Carcinoma

PubMed Central

Smith, Daniel R.; Kunkel, Steven L.; Standiford, Theodore J.; Chensue, Stephen W.; Rolfe, Mark W.; Orringer, Mark B.; Whyte, Richard I.; Burdick, Marie D.; Danforth, Jean M.; Gilbert, Andrew R.; Strieter, Robert M.

1993-01-01

Bronchogenic carcinoma displays an aggressive clinical course that may reflect a capacity to evade host defenses. We postulated that tumors may elaborate interleukin-1 receptor antagonist protein (IRAP) to escape host interleukin-1-dependent responses. Homogenates of human bronchogenic lung tumors demonstrated significant increases of IRAP compared with normal lung tissue controls (n = 48). There was no significant difference in interleukin-1 β levels between tumor and normal lung tissue. Immunohistochemical staining localized IRAP to tumor cells. Semiquantitative pathological analysis demonstrated a modest inflammatory cell infiltrate with qualitative differences between tumors of different histology. Western blot analysis of tumor homogenates demonstrated several molecular weight forms of IRAP. Finally, antigenic IRAP was detected in supernatants of the human bronchogenic carcinoma cell line (A549) maintained in vitro. These findings illustrate the capacity of bronchogenic tumors to produce and secrete IRAP that may be important in tumor evasion of host defenses. ImagesFigure 3Figure 4 PMID:8362978

26 CFR 1.1551-1 - Disallowance of surtax exemption and accumulated earnings credit.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 482, which have the effect of preventing the avoidance or evasion of income taxes. Such principles of... OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) § 1.1551-1 Disallowance... transfer. (b) Purpose of section 1551. The purpose of section 1551 is to prevent avoidance or evasion of...

31 CFR 10.35 - Requirements for covered opinions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... or evasion of any tax imposed by the Internal Revenue Code if the written advice— (1) Is a reliance... the avoidance or evasion of any tax imposed by the Internal Revenue Code if that purpose exceeds any... concerning one or more Federal tax issues arising from— (A) A transaction that is the same as or...

31 CFR 10.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... arrangement, or other plan or arrangement having a potential for tax avoidance or evasion, and representing a... arrangement, or other plan or arrangement having a potential for tax avoidance or evasion; and representing a... paragraphs (a), (b), (c), (d) or (e) of § 10.3. (6) A tax return includes an amended tax return and a claim...

Electronic Invoice in Costa Rica: Challenges for Its Implementation

ERIC Educational Resources Information Center

Ramírez-Jiménez, Juan José; De La O-Selva, Mario; Cortés-Morales, Roberto

2016-01-01

This paper discusses the current situation that Costa Rica faces around fiscal issues and high evasion rates. Using actors and multidimensional analysis, it proposes the electronic invoice as an e-government strategic solution that will close the gap around tax evasion and the government incomes. The success achieved by Brazil in this area…

Constrained orbital intercept-evasion

NASA Astrophysics Data System (ADS)

Zatezalo, Aleksandar; Stipanovic, Dusan M.; Mehra, Raman K.; Pham, Khanh

2014-06-01

An effective characterization of intercept-evasion confrontations in various space environments and a derivation of corresponding solutions considering a variety of real-world constraints are daunting theoretical and practical challenges. Current and future space-based platforms have to simultaneously operate as components of satellite formations and/or systems and at the same time, have a capability to evade potential collisions with other maneuver constrained space objects. In this article, we formulate and numerically approximate solutions of a Low Earth Orbit (LEO) intercept-maneuver problem in terms of game-theoretic capture-evasion guaranteed strategies. The space intercept-evasion approach is based on Liapunov methodology that has been successfully implemented in a number of air and ground based multi-player multi-goal game/control applications. The corresponding numerical algorithms are derived using computationally efficient and orbital propagator independent methods that are previously developed for Space Situational Awareness (SSA). This game theoretical but at the same time robust and practical approach is demonstrated on a realistic LEO scenario using existing Two Line Element (TLE) sets and Simplified General Perturbation-4 (SGP-4) propagator.

Plasticity in early immune evasion strategies of a bacterial pathogen.

PubMed

Bernard, Quentin; Smith, Alexis A; Yang, Xiuli; Koci, Juraj; Foor, Shelby D; Cramer, Sarah D; Zhuang, Xuran; Dwyer, Jennifer E; Lin, Yi-Pin; Mongodin, Emmanuel F; Marques, Adriana; Leong, John M; Anguita, Juan; Pal, Utpal

2018-04-17

Borrelia burgdorferi is one of the few extracellular pathogens capable of establishing persistent infection in mammals. The mechanisms that sustain long-term survival of this bacterium are largely unknown. Here we report a unique innate immune evasion strategy of B. burgdorferi , orchestrated by a surface protein annotated as BBA57, through its modulation of multiple spirochete virulent determinants. BBA57 function is critical for early infection but largely redundant for later stages of spirochetal persistence, either in mammals or in ticks. The protein influences host IFN responses as well as suppresses multiple host microbicidal activities involving serum complement, neutrophils, and antimicrobial peptides. We also discovered a remarkable plasticity in BBA57-mediated spirochete immune evasion strategy because its loss, although resulting in near clearance of pathogens at the inoculum site, triggers nonheritable adaptive changes that exclude detectable nucleotide alterations in the genome but incorporate transcriptional reprograming events. Understanding the malleability in spirochetal immune evasion mechanisms that ensures their host persistence is critical for the development of novel therapeutic and preventive approaches to combat long-term infections like Lyme borreliosis.

Innovations in using virtual reality to study how children cross streets in traffic: evidence for evasive action skills.

PubMed

Morrongiello, Barbara A; Corbett, Michael; Milanovic, Melissa; Pyne, Sarah; Vierich, Robin

2015-08-01

Children in middle childhood are at an increased risk for injury in pedestrian environments. This study examined whether they are capable of showing evasive action (ie, adjusting crossing speed) to avoid injury when crossing streets. The study used a fully immersive virtual reality (VR) system interfaced with a three-dimensional movement measurement system so that the actual crossing behaviour of 7-10-year-old children under different traffic conditions could be precisely measured. Relating outcomes to that which would have been obtained based on using the approach of estimating walking speed and assuming a constant speed provided insights into the realised benefits of the current movement monitoring VR system. Controlling for age and sex, children showed evasive action, crossing more quickly as traffic conditions became more risky. Using an average and assuming a constant walking speed underestimated actual walking speed, failing to capture evasive action and leading to overestimation of children being hit compared with the actual incidence of hits. VR technology is a valuable tool for assessing child pedestrian behaviour. However, systems need to allow the child to cross the street so their level of pedestrian skill is appropriately measured. The current findings provide the first evidence that children are capable of implementing evasive action in reaction to risky traffic conditions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Inflammation promotes oral squamous carcinoma immune evasion via induced programmed death ligand-1 surface expression.

PubMed

Lu, Wanlu; Lu, Libing; Feng, Yun; Chen, Jiao; Li, Yan; Kong, Xiangli; Chen, Sixiu; Li, Xiaoyu; Chen, Qianming; Zhang, Ping

2013-05-01

The association between inflammation and cancer provides a new target for tumor biotherapy. The inflammatory cells and molecules within the tumor microenvironment have decisive dual roles in antitumor immunity and immune evasion. In the present study, phytohemagglutinin (PHA) was used to stimulate peripheral blood mononuclear cells (PBMCs) to simulate the tumor inflammatory microenvironment. The effect of immune cells and inflammatory cytokines on the surface expression of programmed cell death-1 ligand 1 (PD-L1) and tumor immune evasion was investigated using flow cytometry (FCM) and an in vivo xenotransplantation model. Based on the data, PHA-activated, but not resting, immune cells were able to promote the surface expression of PD-L1 in Tca8113 oral squamous carcinoma cells via the secretion of inflammatory cytokines, but not by cell-cell contact. The majority of the inflammatory cytokines had no significant effect on the proliferation, cell cycle progression and apoptosis of the Tca8113 cells, although they each induced the expression of PD-L1 in a dose-dependent manner. In total, 99% of the Tca8113 cells expressed PD-L1 following treatment with the supernatant of PHA-stimulated PBMCs. The PHA-supernatant pretreated Tca8113 cells unusually induced Tca8113 antigen-specific CD8 + T cell apoptosis in vitro and the evasion of antigen-specific T cell attraction in a nude mouse tumor-bearing model. These results indicate a new mechanism for the promotion of tumor immune evasion by the tumor inflammatory microenvironment.

Inflammation promotes oral squamous carcinoma immune evasion via induced programmed death ligand-1 surface expression

PubMed Central

LU, WANLU; LU, LIBING; FENG, YUN; CHEN, JIAO; LI, YAN; KONG, XIANGLI; CHEN, SIXIU; LI, XIAOYU; CHEN, QIANMING; ZHANG, PING

2013-01-01

The association between inflammation and cancer provides a new target for tumor biotherapy. The inflammatory cells and molecules within the tumor microenvironment have decisive dual roles in antitumor immunity and immune evasion. In the present study, phytohemagglutinin (PHA) was used to stimulate peripheral blood mononuclear cells (PBMCs) to simulate the tumor inflammatory microenvironment. The effect of immune cells and inflammatory cytokines on the surface expression of programmed cell death-1 ligand 1 (PD-L1) and tumor immune evasion was investigated using flow cytometry (FCM) and an in vivo xenotransplantation model. Based on the data, PHA-activated, but not resting, immune cells were able to promote the surface expression of PD-L1 in Tca8113 oral squamous carcinoma cells via the secretion of inflammatory cytokines, but not by cell-cell contact. The majority of the inflammatory cytokines had no significant effect on the proliferation, cell cycle progression and apoptosis of the Tca8113 cells, although they each induced the expression of PD-L1 in a dose-dependent manner. In total, 99% of the Tca8113 cells expressed PD-L1 following treatment with the supernatant of PHA-stimulated PBMCs. The PHA-supernatant pretreated Tca8113 cells unusually induced Tca8113 antigen-specific CD8+ T cell apoptosis in vitro and the evasion of antigen-specific T cell attraction in a nude mouse tumor-bearing model. These results indicate a new mechanism for the promotion of tumor immune evasion by the tumor inflammatory microenvironment PMID:23761816

The genomic features of parasitism, Polyembryony and immune evasion in the endoparasitic wasp Macrocentrus cingulum.

PubMed

Yin, Chuanlin; Li, Meizhen; Hu, Jian; Lang, Kun; Chen, Qiming; Liu, Jinding; Guo, Dianhao; He, Kang; Dong, Yipei; Luo, Jiapeng; Song, Zhenkun; Walters, James R; Zhang, Wenqing; Li, Fei; Chen, Xuexin

2018-05-30

Parasitoid wasps are well-known natural enemies of major agricultural pests and arthropod borne diseases. The parasitoid wasp Macrocentrus cingulum (Hymenoptera: Braconidae) has been widely used to control the notorious insect pests Ostrinia furnacalis (Asian Corn Borer) and O. nubilalis (European corn borer). One striking phenomenon exhibited by M. cingulum is polyembryony, the formation of multiple genetically identical offspring from a single zygote. Moreover, M. cingulum employs a passive parasitic strategy by preventing the host's immune system from recognizing the embryo as a foreign body. Thus, the embryos evade the host's immune system and are not encapsulated by host hemocytes. Unfortunately, the mechanism of both polyembryony and immune evasion remains largely unknown. We report the genome of the parasitoid wasp M. cingulum. Comparative genomics analysis of M. cingulum and other 11 insects were conducted, finding some gene families with apparent expansion or contraction which might be linked to the parasitic behaviors or polyembryony of M. cingulum. Moreover, we present the evidence that the microRNA miR-14b regulates the polyembryonic development of M. cingulum by targeting the c-Myc Promoter-binding Protein 1 (MBP-1), histone-lysine N-methyltransferase 2E (KMT2E) and segmentation protein Runt. In addition, Hemomucin, an O-glycosylated transmembrane protein, protects the endoparasitoid wasp larvae from being encapsulated by host hemocytes. Motif and domain analysis showed that only the hemomucin in two endoparasitoids, M. cingulum and Venturia canescens, possessing the ability of passive immune evasion has intact mucin domain and similar O-glycosylation patterns, indicating that the hemomucin is a key factor modulating the immune evasion. The microRNA miR-14b participates in the regulation of polyembryonic development, and the O-glycosylation of the mucin domain in the hemomucin confers the passive immune evasion in this wasp. These key findings provide new insights into the polyembryony and immune evasion.

Animal Enclosure Module (AEM)

NASA Technical Reports Server (NTRS)

1998-01-01

The primary objective of this research project is to test the hypothesis that corticosteroids contribute to the adverse skeletal effects of space flight. To achieve this objective, serum corticosteroids, which are known to increase during space flight, must be maintained at normal physiologic levels in flight rats by a combination of adrenalectomy and corticosteroid supplementation via implanted hormone pellets. Bone analyses in these animals will then be compared to those of intact flight rats that, based on past experience, will undergo corticosteroid excess and bone loss during space flight. The results will reveal whether maintaining serum corticosteroids at physiologic levels in flight rats affects the skeletal abnormalities that normally develop during space flight. A positive response to this question would indicate that the bone loss and decreased bone formation associated with space flight are mediated, at least in part, by corticosteroid excess.

Canadian medical experiments on Shuttle Flight 41-G

NASA Technical Reports Server (NTRS)

Watt, D. G. D.; Money, K. E.; Bondar, R. L.; Thirsk, R. B.; Garneau, M.

1985-01-01

During the 41-G mission, two payload specialist astronauts took part in six Canadian medical experiments designed to measure how the human nervous system adapts to weightlessness, and how this might contribute to space motion sickness. Similar tests conducted pre-flight provided base-line data, and post-flight experiments examined re-adaptation to the ground. No changes were detected in the vestibulo-ocular reflex during this 8-day mission. Pronounced proprioceptive illusions were experienced, especially immediately post-flight. Tactile acuity was normal in the fingers and toes, but the ability to judge limb position was degraded. Estimates of the locations of familiar targets were grossly distorted in the absence of vision. There were no differences in taste thresholds or olfaction. Despite pre-flight tests showing unusual susceptibility to motion sickness, the Canadian payload specialist turned out to be less susceptible than normal on-orbit. Re-adaptation to the normal gravity environment occurred within the first day after landing.

The effects of in-flight treadmill exercise on postflight orthostatic tolerance

NASA Technical Reports Server (NTRS)

Siconolfi, Steven F.; Charles, John B.

1992-01-01

In-flight aerobic exercise is thought to decrease the deconditioning effects of microgravity. Two deconditioning characteristics are the decreases in aerobic capacity (maximum O2 uptake) and an increased cardiovascular response to orthostatic stress (supine to standing). Changes in both parameters were examined after Shuttle flights of 8 to 11 days in astronauts who performed no in-flight exercise, a lower than normal volume of exercise, and a near-normal volume of exercise. The exercise regimen was a traditional continuous protocol. Maximum O2 uptake was maintained in astronauts who completed a near-normal exercise volume of in-flight exercise. Cardiovascular responses to stand test were equivocal among the groups. The use of the traditional exercise regimen as a means to maintain adequate orthostatic responses produced equivocal responses. A different exercise prescription may be more effective in maintaining both exercise capacity and orthostatic tolerance.

14 CFR 27.151 - Flight controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Flight controls. 27.151 Section 27.151... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Flight Characteristics § 27.151 Flight controls. (a) Longitudinal, lateral, directional, and collective controls may not exhibit excessive breakout force, friction...

26 CFR 1.1551-1 - Disallowance of surtax exemption and accumulated earnings credit.

Code of Federal Regulations, 2010 CFR

2010-04-01

... effect of preventing the avoidance or evasion of income taxes. Such principles of law and such provisions... of section 1551. The purpose of section 1551 is to prevent avoidance or evasion of the surtax imposed... OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES § 1.1551-1 Disallowance of surtax...

Immune evasion mechanisms of human papillomavirus: An update.

PubMed

Steinbach, Alina; Riemer, Angelika B

2018-01-15

Human papillomavirus (HPV) is the most frequently sexually transmitted agent in the world. It can cause cervical and other anogenital malignancies, and oropharyngeal cancer. HPV has the unique ability to persist in the host's epithelium for a long time-longer than most viruses do-which is necessary to complete its replication cycle. To this end, HPV has developed a variety of immune evasion mechanisms, which unfortunately also favor the progression of the disease from infection to chronic dysplasia and eventually to cancer. This article summarizes the current knowledge about HPV immune evasion strategies. A special emphasis lies in HPV-mediated changes of the antigen processing machinery, which is generating epitopes for T cells and contributes to the detectability of infected cells. © 2017 UICC.

Pursuit/evasion in orbit

NASA Technical Reports Server (NTRS)

Kelley, H. J.; Cliff, E. M.; Lutze, F. H.

1981-01-01

Maneuvers available to a spacecraft having sufficient propellant to escape an antisatellite satellite (ASAT) attack are examined. The ASAT and the evading spacecraft are regarded as being in circular orbits, and equations of motion are developed for the ASAT to commence a two-impulse maneuver sequence. The ASAT employs thrust impulses which yield a minimum-time-to-rendezvous, considering available fuel. Optimal evasion is shown to involve only in-plane maneuvers, and begins as soon as the ASAT launch information is gathered and thrust activation can be initiated. A closest approach, along with a maximum evasion by the target spacecraft, is calculated to be 14,400 ft. Further research to account for ASATs in parking orbit and for generalization of a continuous control-modeled differential game is indicated.

Study of a pursuit-evasion guidance law for high performance aircraft

NASA Technical Reports Server (NTRS)

Williams, Peggy S.; Menon, P. K. A.; Antoniewicz, Robert F.; Duke, Eugene L.

1989-01-01

The study of a one-on-one aircraft pursuit-evasion guidance scheme for high-performance aircraft is discussed. The research objective is to implement a guidance law derived earlier using differential game theory in conjunction with the theory of feedback linearization. Unlike earlier research in this area, the present formulation explicitly recognizes the two-sided nature of the pursuit-evasion scenario. The present research implements the guidance law in a realistic model of a modern high-performance fighter aircraft. Also discussed are the details of the guidance law, implementation in a highly detailed simulation of a high-performance fighter, and numerical results for two engagement geometries. Modifications of the guidance law for onboard implementation is also discussed.

14 CFR 23.171 - General.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Stability § 23.171 General....181. In addition, the airplane must show suitable stability and control “feel” (static stability) in any condition normally encountered in service, if flight tests show it is necessary for safe operation. ...

14 CFR 23.171 - General.

Code of Federal Regulations, 2014 CFR

2014-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Stability § 23.171 General....181. In addition, the airplane must show suitable stability and control “feel” (static stability) in any condition normally encountered in service, if flight tests show it is necessary for safe operation. ...

14 CFR 23.171 - General.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Stability § 23.171 General....181. In addition, the airplane must show suitable stability and control “feel” (static stability) in any condition normally encountered in service, if flight tests show it is necessary for safe operation. ...

Coping Strategies for Health and Daily-Life Stressors in Patients With Rheumatoid Arthritis, Ankylosing Spondylitis, and Gout

PubMed Central

Peláez-Ballestas, Ingris; Boonen, Annelis; Vázquez-Mellado, Janitzia; Reyes-Lagunes, Isabel; Hernández-Garduño, Adolfo; Goycochea, Maria Victoria; Bernard-Medina, Ana G.; Rodríguez-Amado, Jacqueline; Casasola-Vargas, Julio; Garza-Elizondo, Mario A.; Aceves, Francisco J.; Shumski, Clara; Burgos-Vargas, Ruben

2015-01-01

Abstract This article aims to identify the strategies for coping with health and daily-life stressors of Mexican patients with chronic rheumatic disease. We analyzed the baseline data of a cohort of patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS), and gout. Their strategies for coping were identified with a validated questionnaire. Comparisons between health and daily-life stressors and between the 3 clinical conditions were made. With regression analyses, we determined the contribution of individual, socioeconomic, educational, and health-related quality-of-life variables to health status and coping strategy. We identified several predominant coping strategies in response to daily-life and health stressors in 261 patients with RA, 226 with AS, and 206 with gout. Evasive and reappraisal strategies were predominant when patients cope with health stressors; emotional/negative and evasive strategies predominated when coping with daily-life stressors. There was a significant association between the evasive pattern and the low short-form health survey (SF-36) scores and health stressors across the 3 diseases. Besides some differences between diagnoses, the most important finding was the predominance of the evasive strategy and its association with low SF-36 score and high level of pain in patients with gout. Patients with rheumatic diseases cope in different ways when confronted with health and daily-life stressors. The strategy of coping differs across diagnoses; emotional/negative and evasive strategies are associated with poor health-related quality of life. The identification of the coping strategies could result in the design of psychosocial interventions to improve self-management. PMID:25761177

Coping strategies for health and daily-life stressors in patients with rheumatoid arthritis, ankylosing spondylitis, and gout: STROBE-compliant article.

PubMed

Peláez-Ballestas, Ingris; Boonen, Annelis; Vázquez-Mellado, Janitzia; Reyes-Lagunes, Isabel; Hernández-Garduño, Adolfo; Goycochea, Maria Victoria; Bernard-Medina, Ana G; Rodríguez-Amado, Jacqueline; Casasola-Vargas, Julio; Garza-Elizondo, Mario A; Aceves, Francisco J; Shumski, Clara; Burgos-Vargas, Ruben

2015-03-01

This article aims to identify the strategies for coping with health and daily-life stressors of Mexican patients with chronic rheumatic disease. We analyzed the baseline data of a cohort of patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS), and gout. Their strategies for coping were identified with a validated questionnaire. Comparisons between health and daily-life stressors and between the 3 clinical conditions were made. With regression analyses, we determined the contribution of individual, socioeconomic, educational, and health-related quality-of-life variables to health status and coping strategy. We identified several predominant coping strategies in response to daily-life and health stressors in 261 patients with RA, 226 with AS, and 206 with gout. Evasive and reappraisal strategies were predominant when patients cope with health stressors; emotional/negative and evasive strategies predominated when coping with daily-life stressors. There was a significant association between the evasive pattern and the low short-form health survey (SF-36) scores and health stressors across the 3 diseases. Besides some differences between diagnoses, the most important finding was the predominance of the evasive strategy and its association with low SF-36 score and high level of pain in patients with gout. Patients with rheumatic diseases cope in different ways when confronted with health and daily-life stressors. The strategy of coping differs across diagnoses; emotional/negative and evasive strategies are associated with poor health-related quality of life. The identification of the coping strategies could result in the design of psychosocial interventions to improve self-management.

Complex Immune Evasion Strategies in Classical Hodgkin Lymphoma.

PubMed

Wein, Frederik; Weniger, Marc A; Höing, Benedikt; Arnolds, Judith; Hüttmann, Andreas; Hansmann, Martin-Leo; Hartmann, Sylvia; Küppers, Ralf

2017-12-01

The cellular microenvironment in classical Hodgkin lymphoma (cHL) is dominated by a mixed infiltrate of inflammatory cells with typically only about 1% Hodgkin and Reed/Sternberg (HRS) tumor cells. T cells are usually the largest population of cells in the cHL microenvironment, encompassing T helper (Th) cells, regulatory T cells (Tregs), and cytotoxic T cells. Th cells and Tregs presumably provide essential survival signals for HRS cells. Tregs are also involved in rescuing HRS cells from antitumor immune responses. An understanding of the immune evasion strategies of HRS cells is not only relevant for a characterization of the pathophysiology of cHL but is also clinically relevant, given the current treatment approaches targeting checkpoint inhibitors. Here, we characterized the cHL-specific CD4 + T-cell infiltrate regarding its role in immune evasion. Global gene expression analysis of CD4 + Th cells and Tregs isolated from cHL lymph nodes and reactive tonsils revealed that Treg signatures were enriched in CD4 + Th cells of cHL. Hence, HRS cells may induce Treg differentiation in Th cells, a conclusion supported by in vitro studies with Th cells and cHL cell lines. We also found evidence for immune-suppressive purinergic signaling and a role of the inhibitory receptor-ligand pairs B- and T-cell lymphocyte attenuator-herpesvirus entry mediator and CD200R-CD200 in promoting immune evasion. Taken together, this study highlights the relevance of Treg induction and reveals new immune checkpoint-driven immune evasion strategies in cHL. Cancer Immunol Res; 5(12); 1122-32. ©2017 AACR . ©2017 American Association for Cancer Research.

Mechanisms of virus immune evasion lead to development from chronic inflammation to cancer formation associated with human papillomavirus infection.

PubMed

Senba, Masachika; Mori, Naoki

2012-10-02

Human papillomavirus (HPV) has developed strategies to escape eradication by innate and adaptive immunity. Immune response evasion has been considered an important aspect of HPV persistence, which is the main contributing factor leading to HPV-related cancers. HPV-induced cancers expressing viral oncogenes E6 and E7 are potentially recognized by the immune system. The major histocompatibility complex (MHC) class I molecules are patrolled by natural killer cells and CD8+ cytotoxic T lymphocytes, respectively. This system of recognition is a main target for the strategies of immune evasion deployed by viruses. The viral immune evasion proteins constitute useful tools to block defined stages of the MHC class I presentation pathway, and in this way HPV avoids the host immune response. The long latency period from initial infection to persistence signifies that HPV evolves mechanisms to escape the immune response. It has now been established that there are oncogenic mechanisms by which E7 binds to and degrades tumor suppressor Rb, while E6 binds to and inactivates tumor suppressor p53. Therefore, interaction of p53 and pRb proteins can give rise to an increased immortalization and genomic instability. Overexpression of NF-κB in cervical and penile cancers suggests that NF-κB activation is a key modulator in driving chronic inflammation to cancer. HPV oncogene-mediated suppression of NF-κB activity contributes to HPV escape from the immune system. This review focuses on the diverse mechanisms of the virus immune evasion with HPV that leads to chronic inflammation and cancer.

Ultrasound avoidance behaviour in the bushcricket Tettigonia viridissima (Orthoptera: Tettigoniidae).

PubMed

Schulze, W; Schul, J

2001-02-01

The responses of female Tettigonia viridissima to simulated bat echolocation calls were examined during tethered flight. The insects responded with three distinct behaviours, which occurred at graded stimulus intensities. At low intensities (threshold 54 dB SPL), T. viridissima responded by steering away from the sound source (negative phonotaxis). At intensities approximately 10 dB higher, beating of the hindwing was interrupted, although the insect remained in the flight posture. A diving response (cessation of the wingbeat, closure of the forewings and alignment of the legs against the body) occurred with a threshold of 76 dB SPL. Considering these thresholds, we estimate that the diving response occurs at approximately the sound amplitude at which many aerial-hawking bats first receive echoes from the insect. The other behaviours probably occur before the bat detects the insect and should therefore be interpreted as early avoidance behaviours. The repertoire of startle responses in T. viridissima, with directional and non-directional components, is similar to those of crickets and moths, but quite different from those described for another bushcricket (Neoconocephalus ensiger), which shows only a non-directional response. This supports the conclusion that bat-evasive behaviours are not conserved within the Tettigoniidae, but instead are shaped by the ecological constraints of the insects.

26 CFR 1.269-4 - Power of district director to allocate deduction, credit, or allowance in part.

Code of Federal Regulations, 2011 CFR

2011-04-01

... result in the evasion or avoidance of Federal income tax for which the acquisition was made. The district..., DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible... section 269(a), but only to such extent as he determines will not result in the evasion or avoidance of...

14 CFR 23.61 - Takeoff flight path.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff flight path. 23.61 Section 23.61... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Performance § 23.61 Takeoff flight path. For each commuter category airplane, the takeoff flight path must be determined as follows...

14 CFR 23.61 - Takeoff flight path.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Takeoff flight path. 23.61 Section 23.61... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Performance § 23.61 Takeoff flight path. For each commuter category airplane, the takeoff flight path must be determined as follows...

14 CFR 23.321 - General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.321 General. (a) Flight load factors represent the ratio of the aerodynamic force component (acting normal to... distribution of disposable load within the operating limitations specified in §§ 23.1583 through 23.1589. (c...

Evasion and Interactions of the Humoral Innate Immune Response in Pathogen Invasion, Autoimmune Disease, and Cancer

PubMed Central

Rettig, Trisha A.; Harbin, Julie N.; Harrington, Adelaide; Dohmen, Leonie; Fleming, Sherry D.

2015-01-01

The humoral innate immune system is composed of three major branches, complement, coagulation, and natural antibodies. To persist in the host, pathogens, such as bacteria, viruses, and cancers must evade parts of the innate humoral immune system. Disruptions in the humoral innate immune system also play a role in the development of autoimmune diseases. This review will examine how gram positive bacteria, viruses, cancer, and the autoimmune conditions Systemic Lupus Erythematosus and Anti-phospholipid syndrome, interact with these immune system components. Through examining evasion techniques it becomes clear that interplay between these three systems exists. By exploring the interplay and the evasion/disruption of the humoral innate immune system, we can develop a better understanding of pathogenic infections, cancer, and autoimmune disease development. PMID:26145788

14 CFR 121.419 - Pilots and flight engineers: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2012 CFR

2012-01-01

...; (ix) Flight planning; (x) Each normal and emergency procedure; and (xi) The approved Airplane Flight... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Pilots and flight engineers: Initial... Program § 121.419 Pilots and flight engineers: Initial, transition, and upgrade ground training. (a...

14 CFR 121.419 - Pilots and flight engineers: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2011 CFR

2011-01-01

...; (ix) Flight planning; (x) Each normal and emergency procedure; and (xi) The approved Airplane Flight... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Pilots and flight engineers: Initial... Program § 121.419 Pilots and flight engineers: Initial, transition, and upgrade ground training. (a...

14 CFR 121.419 - Pilots and flight engineers: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2014 CFR

2014-01-01

...; (ix) Flight planning; (x) Each normal and emergency procedure; and (xi) The approved Airplane Flight... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Pilots and flight engineers: Initial... Program § 121.419 Pilots and flight engineers: Initial, transition, and upgrade ground training. Link to...

14 CFR 121.419 - Pilots and flight engineers: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2010 CFR

2010-01-01

...; (ix) Flight planning; (x) Each normal and emergency procedure; and (xi) The approved Airplane Flight... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Pilots and flight engineers: Initial... Program § 121.419 Pilots and flight engineers: Initial, transition, and upgrade ground training. (a...

14 CFR 121.419 - Pilots and flight engineers: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2013 CFR

2013-01-01

...; (ix) Flight planning; (x) Each normal and emergency procedure; and (xi) The approved Airplane Flight... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Pilots and flight engineers: Initial... Program § 121.419 Pilots and flight engineers: Initial, transition, and upgrade ground training. (a...

The Organization for Economic Cooperation and Development

DTIC Science & Technology

2010-02-08

experience of OECD members with bilateral treaties, the increasingly sophisticated methods for tax evasion , and the development of new and more complex...new efforts to curtail the use of tax havens for tax avoidance , combined with efforts since the terrorist...addition, on May 4, 2009, President Obama announced a set of proposals to, “crack down on illegal overseas tax evasion , close loopholes, and make it

Defense Industrial Personnel Security Clearance Review Program

DTIC Science & Technology

1992-01-02

or on closed accounts. 5. Indication of deceit or deception in obtaining credit or bank accounts, misappropriation of funds, income tax evasion ...income tax evasion , expense account fraud, filing deceptive loan statements, and other intentional financial breaches of trust; (3) inability or...information; or any U.S. citizen nominated by the Red Cross or United Service Organizations for assignment with the Military Services overseas. The

"Did You Pay Your Taxes?" How (Not) to Conduct Tax Evasion Surveys in Transition Countries

ERIC Educational Resources Information Center

Gerxhani, Klarita

2007-01-01

Gathering large-scale data on tax evasion is an undisputable challenge in and of itself. Doing so in a country in transition from a communist to a democratic system is even more difficult. This paper discusses the challenges and presents a case study to show how they can be dealt with effectively. One important implication of the paper is that…

14 CFR 27.321 - General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.321 General. (a) The flight load factor must be assumed to act normal to the longitudinal axis of the rotorcraft, and to be equal... from the design minimum weight to the design maximum weight; and (2) With any practical distribution of...

14 CFR 27.1303 - Flight and navigation instruments.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight and navigation instruments. 27.1303... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment General § 27.1303 Flight and navigation instruments. The following are the required flight and navigation instruments: (a) An airspeed...

14 CFR 27.1303 - Flight and navigation instruments.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight and navigation instruments. 27.1303... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment General § 27.1303 Flight and navigation instruments. The following are the required flight and navigation instruments: (a) An airspeed...

14 CFR 27.1303 - Flight and navigation instruments.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flight and navigation instruments. 27.1303... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment General § 27.1303 Flight and navigation instruments. The following are the required flight and navigation instruments: (a) An airspeed...

Take-over performance in evasive manoeuvres.

PubMed

Happee, Riender; Gold, Christian; Radlmayr, Jonas; Hergeth, Sebastian; Bengler, Klaus

2017-09-01

We investigated after effects of automation in take-over scenarios in a high-end moving-base driving simulator. Drivers performed evasive manoeuvres encountering a blocked lane in highway driving. We compared the performance of drivers 1) during manual driving, 2) after automated driving with eyes on the road while performing the cognitively demanding n-back task, and 3) after automated driving with eyes off the road performing the visually demanding SuRT task. Both minimum time to collision (TTC) and minimum clearance towards the obstacle disclosed a substantial number of near miss events and are regarded as valuable surrogate safety metrics in evasive manoeuvres. TTC proved highly sensitive to the applied definition of colliding paths, and we prefer robust solutions using lane position while disregarding heading. The extended time to collision (ETTC) which takes into account acceleration was close to the more robust conventional TTC. In line with other publications, the initial steering or braking intervention was delayed after using automation compared to manual driving. This resulted in lower TTC values and stronger steering and braking actions. Using automation, effects of cognitive distraction were similar to visual distraction for the intervention time with effects on the surrogate safety metric TTC being larger with visual distraction. However the precision of the evasive manoeuvres was hardly affected with a similar clearance towards the obstacle, similar overshoots and similar excursions to the hard shoulder. Further research is needed to validate and complement the current simulator based results with human behaviour in real world driving conditions. Experiments with real vehicles can disclose possible systematic differences in behaviour, and naturalistic data can serve to validate surrogate safety measures like TTC and obstacle clearance in evasive manoeuvres. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Lewis Lung Cancer Cells Promote SIGNR1(CD209b)-Mediated Macrophages Polarization Induced by IL-4 to Facilitate Immune Evasion.

PubMed

Yan, Xiaolong; Li, Wenhai; Pan, Lei; Fu, Enqing; Xie, Yonghong; Chen, Min; Mu, Deguang

2016-05-01

Tumor-associated macrophages are a prominent component of lung cancer and contribute to tumor progression by facilitating the immune evasion of cancer cells. DC-SIGN (CD209) assists in the immune evasion of a broad spectrum of pathogens and neoplasms by inhibiting the maturation of DCs and subsequent cytokines production. However, the expression of DC-SIGN in macrophages and its role in mediating immune evasion in lung cancer and the underlying mechanism remain unclear. Our study aimed to identify the immunosuppressive role of SIGNR1 in murine macrophage differentiation and lung cancer progression. We found that SIGNR1-positive RAW264.7 macrophages were enriched in mixed cultures with Lewis lung cancer cells (LLC) (ratio of RAW 264.7 to LLC being 1:1) after stimulation with IL-4. Moreover, LLC-educated macrophages exhibited significantly higher levels of IL-10 but lower IL-12 in response to IL-4 treatment as determined by RT-PCR and ELISA. However, inhibition of SIGNR1 markedly hampered the production of IL-10, indicating that SIGNR1 was indispensable for IL-4+LLC induced macrophage polarization towards the M2 subtype. Furthermore, polarized M2 cells immersed in a tumor microenvironment promoted the migration of LLCs, as measured by transwell assays, but migration was suppressed after blockade of SIGNR1 using CD209b antibody. In addition, IL-4+LLC-educated macrophages reduced the proliferation of the activated T cells and reduced IFN-γ-mediated Th1 response in T cells, while SIGNR1 inhibition rescued Th1 cell functions. In conclusion, murine SIGNR1 expressed in LLC-educated macrophages appears to mediate IL-4-induced RAW264.7 macrophage polarization and thus facilitate lung cancer evasion. © 2015 Wiley Periodicals, Inc.

Porphyromonas gingivalis evasion of autophagy and intracellular killing by human myeloid dendritic cells involves DC-SIGN-TLR2 crosstalk.

PubMed

El-Awady, Ahmed R; Miles, Brodie; Scisci, Elizabeth; Kurago, Zoya B; Palani, Chithra D; Arce, Roger M; Waller, Jennifer L; Genco, Caroline A; Slocum, Connie; Manning, Matthew; Schoenlein, Patricia V; Cutler, Christopher W

2015-02-01

Signaling via pattern recognition receptors (PRRs) expressed on professional antigen presenting cells, such as dendritic cells (DCs), is crucial to the fate of engulfed microbes. Among the many PRRs expressed by DCs are Toll-like receptors (TLRs) and C-type lectins such as DC-SIGN. DC-SIGN is targeted by several major human pathogens for immune-evasion, although its role in intracellular routing of pathogens to autophagosomes is poorly understood. Here we examined the role of DC-SIGN and TLRs in evasion of autophagy and survival of Porphyromonas gingivalis in human monocyte-derived DCs (MoDCs). We employed a panel of P. gingivalis isogenic fimbriae deficient strains with defined defects in Mfa-1 fimbriae, a DC-SIGN ligand, and FimA fimbriae, a TLR2 agonist. Our results show that DC-SIGN dependent uptake of Mfa1+P. gingivalis strains by MoDCs resulted in lower intracellular killing and higher intracellular content of P. gingivalis. Moreover, Mfa1+P. gingivalis was mostly contained within single membrane vesicles, where it survived intracellularly. Survival was decreased by activation of TLR2 and/or autophagy. Mfa1+P. gingivalis strain did not induce significant levels of Rab5, LC3-II, and LAMP1. In contrast, P. gingivalis uptake through a DC-SIGN independent manner was associated with early endosomal routing through Rab5, increased LC3-II and LAMP-1, as well as the formation of double membrane intracellular phagophores, a characteristic feature of autophagy. These results suggest that selective engagement of DC-SIGN by Mfa-1+P. gingivalis promotes evasion of antibacterial autophagy and lysosome fusion, resulting in intracellular persistence in myeloid DCs; however TLR2 activation can overcome autophagy evasion and pathogen persistence in DCs.

Color-blind racial ideology: theory, training, and measurement implications in psychology.

PubMed

Neville, Helen A; Awad, Germine H; Brooks, James E; Flores, Michelle P; Bluemel, Jamie

2013-09-01

Synthesizing the interdisciplinary literature, we characterize color-blind racial ideology (CBRI) as consisting of two interrelated domains: color-evasion (i.e., denial of racial differences by emphasizing sameness) and power-evasion (i.e., denial of racism by emphasizing equal opportunities). Mounting empirical data suggest that the color-evasion dimension is ineffective and in fact promotes interracial tension and potential inequality. CBRI may be conceived as an ultramodern or contemporary form of racism and a legitimizing ideology used to justify the racial status quo. Four types of CBRI are described: denial of (a) race, (b) blatant racial issues, (c) institutional racism, and (d) White privilege. We discuss empirical findings suggesting a relationship between CBRI and increased racial prejudice, racial anger, and racial fear. Implications for education, training, and research are provided. © 2013 APA, all rights reserved.

Epigenetic regulation of immune checkpoints: another target for cancer immunotherapy?

PubMed

Ali, Mahmoud A; Matboli, Marwa; Tarek, Marwa; Reda, Maged; Kamal, Kamal M; Nouh, Mahmoud; Ashry, Ahmed M; El-Bab, Ahmed Fath; Mesalam, Hend A; Shafei, Ayman El-Sayed; Abdel-Rahman, Omar

2017-01-01

Epigenetic changes in oncogenes and tumor-suppressor genes contribute to carcinogenesis. Understanding the epigenetic and genetic components of tumor immune evasion is crucial. Few cancer genetic mutations have been linked to direct correlations with immune evasion. Studies on the epigenetic modulation of the immune checkpoints have revealed a critical interaction between epigenetic and immune modulation. Epigenetic modifiers can activate many silenced genes. Some of them are immune checkpoints regulators that turn on immune responses and others turn them off resulting in immune evasion. Many forms of epigenetic inheritance mechanisms may play a role in regulation of immune checkpoints including: covalent modifications, noncoding RNA and histone modifications. In this review, we will show how the potential interaction between epigenetic and immune modulation may lead to new approaches for specific epigenome/immunome-targeted therapies for cancer.

Analysing and controlling the tax evasion dynamics via majority-vote model

NASA Astrophysics Data System (ADS)

Lima, F. W. S.

2010-09-01

Within the context of agent-based Monte-Carlo simulations, we study the well-known majority-vote model (MVM) with noise applied to tax evasion on simple square lattices, Voronoi-Delaunay random lattices, Barabasi-Albert networks, and Erdös-Rényi random graphs. In the order to analyse and to control the fluctuations for tax evasion in the economics model proposed by Zaklan, MVM is applied in the neighborhod of the noise critical qc to evolve the Zaklan model. The Zaklan model had been studied recently using the equilibrium Ising model. Here we show that the Zaklan model is robust because this can be studied using equilibrium dynamics of Ising model also through the nonequilibrium MVM and on various topologies cited above giving the same behavior regardless of dynamic or topology used here.

Viral evasion of DNA-stimulated innate immune responses

PubMed Central

Christensen, Maria H; Paludan, Søren R

2017-01-01

Cellular sensing of virus-derived nucleic acids is essential for early defenses against virus infections. In recent years, the discovery of DNA sensing proteins, including cyclic GMP–AMP synthase (cGAS) and gamma-interferon-inducible protein (IFI16), has led to understanding of how cells evoke strong innate immune responses against incoming pathogens carrying DNA genomes. The signaling stimulated by DNA sensors depends on the adaptor protein STING (stimulator of interferon genes), to enable expression of antiviral proteins, including type I interferon. To facilitate efficient infections, viruses have evolved a wide range of evasion strategies, targeting host DNA sensors, adaptor proteins and transcription factors. In this review, the current literature on virus-induced activation of the STING pathway is presented and we discuss recently identified viral evasion mechanisms targeting different steps in this antiviral pathway. PMID:26972769

Immune evasion mechanisms and immune checkpoint inhibition in advanced merkel cell carcinoma.

PubMed

Schadendorf, Dirk; Nghiem, Paul; Bhatia, Shailender; Hauschild, Axel; Saiag, Philippe; Mahnke, Lisa; Hariharan, Subramanian; Kaufman, Howard L

2017-01-01

Merkel cell carcinoma (MCC) is a rare skin cancer caused by Merkel cell polyomavirus (MCPyV) infection and/or ultraviolet radiation-induced somatic mutations. The presence of tumor-infiltrating lymphocytes is evidence that an active immune response to MCPyV and tumor-associated neoantigens occurs in some patients. However, inhibitory immune molecules, including programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1), within the MCC tumor microenvironment aid in tumor evasion of T-cell-mediated clearance. Unlike chemotherapy, treatment with anti-PD-L1 (avelumab) or anti-PD-1 (pembrolizumab) antibodies leads to durable responses in MCC, in both virus-positive and virus-negative tumors. As many tumors are established through the evasion of infiltrating immune-cell clearance, the lessons learned in MCC may be broadly relevant to many cancers.

Herpesvirus Evasion of Natural Killer Cells.

PubMed

De Pelsmaeker, Steffi; Romero, Nicolas; Vitale, Massimo; Favoreel, Herman W

2018-06-01

Natural killer (NK) cells play an important role in the host response against viral infections and cancer development. They are able to kill virus-infected and tumor cells, and they produce different important cytokines that stimulate the antiviral and antitumor adaptive immune response, particularly interferon gamma. NK cells are of particular importance in herpesvirus infections, which is illustrated by systemic and life-threatening herpesvirus disease symptoms in patients with deficiencies in NK cell activity and by the myriad of reports describing herpesvirus NK cell evasion strategies. The latter is particularly obvious for cytomegaloviruses, but increasing evidence indicates that most, if not all, members of the herpesvirus family suppress NK cell activity to some extent. This review discusses the different NK cell evasion strategies described for herpesviruses and how this knowledge may translate to clinical applications. Copyright © 2018 American Society for Microbiology.

Normobaric hypoxia inhalation test vs. response to airline flight in healthy passengers.

PubMed

Kelly, Paul T; Swanney, Maureen P; Frampton, Chris; Seccombe, Leigh M; Peters, Matthew J; Beckert, Lutz E

2006-11-01

There is little data available to determine the normal response to normobaric hypoxia inhalation testing (NHIT) and air travel. Quantifying a healthy response may assist in the evaluation of passengers considered at risk for air travel. The aims of this study were: (1) to quantify the degree of desaturation in healthy subjects during a NHIT and air travel; and (2) assess the validity of the NHIT when compared with actual in-flight responses. There were 15 healthy adults (age 23-57; 10 women) who volunteered for this study. Preflight tests included lung function, arterial blood gas, pulse oximetry (SpO2), and NHIT (inspired oxygen 15%). SpO2 and cabin pressure were measured continuously on each subject during a commercial air flight (mean cabin altitude 2178 m; range 1719-2426 m). In-flight oxygenation was compared with the preflight NHIT. Lung function testing results were normal. There was significant desaturation (SpO2) during the NHIT (pre: 98 +/- 2%; post: 92 +/- 2%) and at cruising altitude (pre: 97 +/- 1%; cruise: 92 +/- 2%). There was no difference between the final NHIT SpO2 and the mean in-flight SpO2. There was a significant difference between the lowest in-flight SpO2 (88 +/- 2%) vs. the lowest NHIT SpO2, (90 +/- 2%). Oxygen saturation decreases significantly during air travel in normal individuals. In this group of healthy passengers the NHIT approximates some, but not all, aspects of in-flight oxygenation. These results can be used to describe a normal response to the NHIT and air-travel.

Columbia: The first five flights entry heating data series. Volume 2: The OMS Pod

NASA Technical Reports Server (NTRS)

Williams, S. D.

1983-01-01

Entry heating flight data and wind tunnel data on the OMS Pod are presented for the first five flights of the Space Shuttle Orbiter. The heating rate data are presented in terms of normalized film heat transfer coefficients as a function of angle-of-attack, Mach number, and normal shock Reynolds number. The surface heating rates and temperatures were obtained via the JSC NONLIN/INVERSE computer program. Time history plots of the surface heating rates and temperatures are also presented.

14 CFR 23.333 - Flight envelope.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight envelope. 23.333 Section 23.333... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.333 Flight envelope. (a) General. Compliance with the strength requirements of this subpart must be shown at...

14 CFR 23.333 - Flight envelope.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flight envelope. 23.333 Section 23.333... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.333 Flight envelope. (a) General. Compliance with the strength requirements of this subpart must be shown at...

14 CFR 23.333 - Flight envelope.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Flight envelope. 23.333 Section 23.333... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.333 Flight envelope. (a) General. Compliance with the strength requirements of this subpart must be shown at...

14 CFR 27.1335 - Flight director systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight director systems. 27.1335 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Instruments: Installation § 27.1335 Flight director systems. If a flight director system is installed, means must be provided to indicate to the...

14 CFR 27.1335 - Flight director systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight director systems. 27.1335 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Instruments: Installation § 27.1335 Flight director systems. If a flight director system is installed, means must be provided to indicate to the...

14 CFR 23.333 - Flight envelope.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flight envelope. 23.333 Section 23.333... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.333 Flight envelope. (a) General. Compliance with the strength requirements of this subpart must be shown at...

14 CFR 23.333 - Flight envelope.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight envelope. 23.333 Section 23.333... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.333 Flight envelope. (a) General. Compliance with the strength requirements of this subpart must be shown at...

Estimating insect flight densities from attractive trap catches and flight height distributions

USDA-ARS?s Scientific Manuscript database

Insect species often exhibit a specific mean flight height and vertical flight distribution that approximates a normal distribution with a characteristic standard deviation (SD). Many studies in the literature report catches on passive (non-attractive) traps at several heights. These catches were us...

Changes in gastric myoelectric activity during space flight

NASA Technical Reports Server (NTRS)

Harm, Deborah L.; Sandoz, Gwenn R.; Stern, Robert M.

2002-01-01

The purpose of the present study was to examine postprandial myoelectric activity of the stomach and gastric activity associated with space motion sickness using electrogastrography. Three crewmembers participated in this investigation. Preflight, subjects exhibited normal postprandial responses to the ingestion of a meal. Inflight, crewmembers exhibited an abnormal decrease in the power of the normal gastric slow wave after eating on flight day 1, but had a normal postprandial response by flight day 3. Prior to and during episodes of nausea and vomiting, the electrical activity of the stomach became dysrhythmic with 60-80% of the spectral power in the bradygastric and tachygastric frequency ranges. These findings indicate that gastric motility may be decreased during the first few days of space flight. In addition, changes in the frequency of the gastric slow wave associated with space motion sickness symptoms are consistent with those reported for laboratory-induced motion sickness.

Let’s Tie the Knot: Marriage of Complement and Adaptive Immunity in Pathogen Evasion, for Better or Worse

PubMed Central

Bennett, Kaila M.; Rooijakkers, Suzan H. M.; Gorham, Ronald D.

2017-01-01

The complement system is typically regarded as an effector arm of innate immunity, leading to recognition and killing of microbial invaders in body fluids. Consequently, pathogens have engaged in an arms race, evolving molecules that can interfere with proper complement responses. However, complement is no longer viewed as an isolated system, and links with other immune mechanisms are continually being discovered. Complement forms an important bridge between innate and adaptive immunity. While its roles in innate immunity are well-documented, its function in adaptive immunity is less characterized. Therefore, it is no surprise that the field of pathogenic complement evasion has focused on blockade of innate effector functions, while potential inhibition of adaptive immune responses (via complement) has been overlooked to a certain extent. In this review, we highlight past and recent developments on the involvement of complement in the adaptive immune response. We discuss the mechanisms by which complement aids in lymphocyte stimulation and regulation, as well as in antigen presentation. In addition, we discuss microbial complement evasion strategies, and highlight specific examples in the context of adaptive immune responses. These emerging ties between complement and adaptive immunity provide a catalyst for future discovery in not only the field of adaptive immune evasion but in elucidating new roles of complement. PMID:28197139

Step-wise loss of bacterial flagellar torsion confers progressive phagocytic evasion.

PubMed

Lovewell, Rustin R; Collins, Ryan M; Acker, Julie L; O'Toole, George A; Wargo, Matthew J; Berwin, Brent

2011-09-01

Phagocytosis of bacteria by innate immune cells is a primary method of bacterial clearance during infection. However, the mechanisms by which the host cell recognizes bacteria and consequentially initiates phagocytosis are largely unclear. Previous studies of the bacterium Pseudomonas aeruginosa have indicated that bacterial flagella and flagellar motility play an important role in colonization of the host and, importantly, that loss of flagellar motility enables phagocytic evasion. Here we use molecular, cellular, and genetic methods to provide the first formal evidence that phagocytic cells recognize bacterial motility rather than flagella and initiate phagocytosis in response to this motility. We demonstrate that deletion of genes coding for the flagellar stator complex, which results in non-swimming bacteria that retain an initial flagellar structure, confers resistance to phagocytic binding and ingestion in several species of the gamma proteobacterial group of Gram-negative bacteria, indicative of a shared strategy for phagocytic evasion. Furthermore, we show for the first time that susceptibility to phagocytosis in swimming bacteria is proportional to mot gene function and, consequently, flagellar rotation since complementary genetically- and biochemically-modulated incremental decreases in flagellar motility result in corresponding and proportional phagocytic evasion. These findings identify that phagocytic cells respond to flagellar movement, which represents a novel mechanism for non-opsonized phagocytic recognition of pathogenic bacteria.

Step-Wise Loss of Bacterial Flagellar Torsion Confers Progressive Phagocytic Evasion

PubMed Central

Lovewell, Rustin R.; Collins, Ryan M.; Acker, Julie L.; O'Toole, George A.; Wargo, Matthew J.; Berwin, Brent

2011-01-01

Phagocytosis of bacteria by innate immune cells is a primary method of bacterial clearance during infection. However, the mechanisms by which the host cell recognizes bacteria and consequentially initiates phagocytosis are largely unclear. Previous studies of the bacterium Pseudomonas aeruginosa have indicated that bacterial flagella and flagellar motility play an important role in colonization of the host and, importantly, that loss of flagellar motility enables phagocytic evasion. Here we use molecular, cellular, and genetic methods to provide the first formal evidence that phagocytic cells recognize bacterial motility rather than flagella and initiate phagocytosis in response to this motility. We demonstrate that deletion of genes coding for the flagellar stator complex, which results in non-swimming bacteria that retain an initial flagellar structure, confers resistance to phagocytic binding and ingestion in several species of the gamma proteobacterial group of Gram-negative bacteria, indicative of a shared strategy for phagocytic evasion. Furthermore, we show for the first time that susceptibility to phagocytosis in swimming bacteria is proportional to mot gene function and, consequently, flagellar rotation since complementary genetically- and biochemically-modulated incremental decreases in flagellar motility result in corresponding and proportional phagocytic evasion. These findings identify that phagocytic cells respond to flagellar movement, which represents a novel mechanism for non-opsonized phagocytic recognition of pathogenic bacteria. PMID:21949654

Immune Evasion Strategies of Pathogens in Macrophages: the Potential for Limiting Pathogen Transmission.

PubMed

Ren, Yuwei; Khan, Faheem Ahmed; Pandupuspitasari, Nuruliarizki Shinta; Zhang, Shujun

2017-01-01

Preventing pathogen transmission to a new host is of major interest to the immunologist and could benefit from a detailed investigation of pathogen immune evasion strategies. The first line of defense against pathogen invasion is provided by macrophages. When they sense pathogens, macrophages initiate signals to inflammatory and pro-inflammatory cytokines through pattern recognition receptors (PRRs) subsequently mediating phagocytosis and inflammation. The macrophage immune machinery classically includes two subsets: the activated M1 and the activated M2 that respond accordingly in diverse immune challenges. The lipid and glycogen metabolic pathways work together with the lysosome to help the mature phagosome to degrade and eliminate intracellular pathogens in macrophages. The viral evasion strategies are even more complex due to the interplay between autophagy and apoptosis. However, pathogens evolve several strategies to camouflage themselves against immune responses in order to ensure their survival, replication and transmission. These strategies include the muting of PRRs initiated inflammatory responses, attenuation of M1 and/or induction of M2 macrophages, suppression of autophago-lysosomal formation, interference with lipid and glycogen metabolism, and viral mediation of autophagy and apoptosis cross-talk to enhance viral replication. This review focuses on pathogen immune evasion methods and on the strategies used by the host against camouflaged pathogens.

Let's Tie the Knot: Marriage of Complement and Adaptive Immunity in Pathogen Evasion, for Better or Worse.

PubMed

Bennett, Kaila M; Rooijakkers, Suzan H M; Gorham, Ronald D

2017-01-01

The complement system is typically regarded as an effector arm of innate immunity, leading to recognition and killing of microbial invaders in body fluids. Consequently, pathogens have engaged in an arms race, evolving molecules that can interfere with proper complement responses. However, complement is no longer viewed as an isolated system, and links with other immune mechanisms are continually being discovered. Complement forms an important bridge between innate and adaptive immunity. While its roles in innate immunity are well-documented, its function in adaptive immunity is less characterized. Therefore, it is no surprise that the field of pathogenic complement evasion has focused on blockade of innate effector functions, while potential inhibition of adaptive immune responses (via complement) has been overlooked to a certain extent. In this review, we highlight past and recent developments on the involvement of complement in the adaptive immune response. We discuss the mechanisms by which complement aids in lymphocyte stimulation and regulation, as well as in antigen presentation. In addition, we discuss microbial complement evasion strategies, and highlight specific examples in the context of adaptive immune responses. These emerging ties between complement and adaptive immunity provide a catalyst for future discovery in not only the field of adaptive immune evasion but in elucidating new roles of complement.

Interleukin-36 cytokines may overcome microbial immune evasion strategies that inhibit interleukin-1 family signaling.

PubMed

Jensen, Liselotte E

2017-08-15

Pathogens deploy immune evasion strategies to successfully establish infections within their hosts. Naturally, the host responds by acquiring mechanisms to counter these strategies. There is increasing evidence that the three interleukin-36 (IL-36) cytokines, IL-36α, IL-36β and IL-36γ, play important roles in host immunity. With a focus on the skin as a target for microbial and viral invasion, the current knowledge of IL-36 functions is reviewed. Furthermore, the hypothesis that the IL-36s have evolved to counteract virulence factors is presented using viruses as an example. The IL-36s are related to IL-1α, IL-1β, IL-18, and IL-33. Numerous viruses affecting the skin have developed immune evasion strategies that neutralize IL-1α, IL-1β, or IL-18 signaling or combinations of these pathways. Through small differences in activation mechanisms and receptor utilization, it is possible that IL-36 signaling may proceed unhindered in the presence of these viral inhibitors. Thus, one physiological function of the IL-36s may be to counteract microbial immune evasion. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Unpredictability of escape trajectory explains predator evasion ability and microhabitat preference of desert rodents.

PubMed

Moore, Talia Y; Cooper, Kimberly L; Biewener, Andrew A; Vasudevan, Ramanarayan

2017-09-05

Mechanistically linking movement behaviors and ecology is key to understanding the adaptive evolution of locomotion. Predator evasion, a behavior that enhances fitness, may depend upon short bursts or complex patterns of locomotion. However, such movements are poorly characterized by existing biomechanical metrics. We present methods based on the entropy measure of randomness from Information Theory to quantitatively characterize the unpredictability of non-steady-state locomotion. We then apply the method by examining sympatric rodent species whose escape trajectories differ in dimensionality. Unlike the speed-regulated gait use of cursorial animals to enhance locomotor economy, bipedal jerboa (family Dipodidae) gait transitions likely enhance maneuverability. In field-based observations, jerboa trajectories are significantly less predictable than those of quadrupedal rodents, likely increasing predator evasion ability. Consistent with this hypothesis, jerboas exhibit lower anxiety in open fields than quadrupedal rodents, a behavior that varies inversely with predator evasion ability. Our unpredictability metric expands the scope of quantitative biomechanical studies to include non-steady-state locomotion in a variety of evolutionary and ecologically significant contexts.Biomechanical understanding of animal gait and maneuverability has primarily been limited to species with more predictable, steady-state movement patterns. Here, the authors develop a method to quantify movement predictability, and apply the method to study escape-related movement in several species of desert rodents.

Experimental Economies and Tax Evasion: The Order Beyond the Market

NASA Astrophysics Data System (ADS)

Bernhofer, Juliana

Research on tax evasion will probably never get old. As long as there are taxes, there will also be policy-makers all over the world eager to tackle deviant conduct in the most efficient and efficacious way. To fill this purpose a number of theoretical and empirical frameworks have been developed in economics over the last decades, starting from the classical models of Allingham and Sandmo (1972) where individuals were assumed to be perfectly rational following a pure cost-benefit logic. Today, however, we look at a body of literature which has opened up to a number of new and interdisciplinary findings, also thanks to the inclusion of behavioral aspects that do not necessarily follow the paradigms of the homo economicus. To this end, the discipline of Experimental Economics has developed numerous ways to overcome the distance between economic theory and human behavior. The aim of this survey is to take the reader on a tour through some of these methodologies applied to the analysis of tax evasion, arguing that further research should focus on integrating multi-agent simulation models with outcomes from human subject experiments in order to create useful and necessary tools to administer, consolidate and represent the complex theoretical, empirical and experimental panorama of tax evasion research.

14 CFR 23.971 - Fuel tank sump.

Code of Federal Regulations, 2010 CFR

2010-01-01

... ground and flight attitudes, of 0.25 percent of the tank capacity, or 1/16 gallon, whichever is greater... to its sump with the airplane in the normal ground attitude. (c) Each reciprocating engine fuel... normal flight attitude, water will drain from all parts of the tank except the sump to the sediment bowl...

14 CFR 23.1567 - Flight maneuver placard.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight maneuver placard. 23.1567 Section 23... Information Markings and Placards § 23.1567 Flight maneuver placard. (a) For normal category airplanes, there... the approved acrobatic maneuvers and the recommended entry airspeed for each. If inverted flight...

14 CFR 23.1567 - Flight maneuver placard.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight maneuver placard. 23.1567 Section 23... Information Markings and Placards § 23.1567 Flight maneuver placard. (a) For normal category airplanes, there... the approved acrobatic maneuvers and the recommended entry airspeed for each. If inverted flight...

14 CFR 27.1459 - Flight data recorders.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight data recorders. 27.1459 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Safety Equipment § 27.1459 Flight data recorders. (a) Each flight recorder required by the operating rules of Subchapter G of this chapter must be...

14 CFR 27.1459 - Flight data recorders.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight data recorders. 27.1459 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Safety Equipment § 27.1459 Flight data recorders. (a) Each flight recorder required by the operating rules of Subchapter G of this chapter must be...

14 CFR 27.673 - Primary flight control.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Primary flight control. 27.673 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.673 Primary flight control. Primary flight controls are those used by the pilot for immediate control of pitch, roll...

14 CFR 27.673 - Primary flight control.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Primary flight control. 27.673 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.673 Primary flight control. Primary flight controls are those used by the pilot for immediate control of pitch, roll...

14 CFR 23.673 - Primary flight controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Primary flight controls. 23.673 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.673 Primary flight controls. Primary flight controls are those used by the pilot for...

14 CFR 23.673 - Primary flight controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Primary flight controls. 23.673 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.673 Primary flight controls. Primary flight controls are those used by the pilot for...

14 CFR 23.673 - Primary flight controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Primary flight controls. 23.673 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.673 Primary flight controls. Primary flight controls are those used by the pilot for...

14 CFR 23.673 - Primary flight controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Primary flight controls. 23.673 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.673 Primary flight controls. Primary flight controls are those used by the pilot for...

14 CFR 23.673 - Primary flight controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Primary flight controls. 23.673 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.673 Primary flight controls. Primary flight controls are those used by the pilot for...

14 CFR 27.673 - Primary flight control.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.673 Primary flight control. Primary flight controls are those used by the pilot for immediate control of pitch, roll... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Primary flight control. 27.673 Section 27...

A kinematic/kinetic hybrid airplane simulator model : draft.

DOT National Transportation Integrated Search

2008-01-01

A kinematics-based flight model, for normal flight : regimes, currently uses precise flight data to achieve a high : level of aircraft realism. However, it was desired to further : increase the models accuracy, without a substantial increase in : ...

A kinematic/kinetic hybrid airplane simulator model.

DOT National Transportation Integrated Search

2008-01-01

A kinematics-based flight model, for normal flight : regimes, currently uses precise flight data to achieve a high : level of aircraft realism. However, it was desired to further : increase the models accuracy, without a substantial increase in : ...

Crew performance and communication: Performing a terrain navigation task

NASA Technical Reports Server (NTRS)

Battiste, Vernol; Delzell, Susanne

1993-01-01

A study was conducted to examine the map and route cues pilots use while navigating under controlled, but realistic, nap-of-the-earth (NOE) flight conditions. US Army helicopter flight crews were presented a map and route overlay and asked to perform normal mission planning. They then viewed a video-recording of the out-the-window scene during low-level flights, without the route overlay, and were asked periodically to locate their current position on the map. The pilots and navigators were asked to communicate normally during the planning and flight phases. During each flight the navigator's response time, accuracy, and subjective workload were assessed. Post-flight NASA-TLX workload ratings were collected. No main effect of map orientation (north-up vs. track-up) was found for errors or response times on any of the tasks evaluated. Navigators in the north-up group rated their workload lower than those in the track-up group.

Experiment K-313: Rat and quail ontogenesis

NASA Technical Reports Server (NTRS)

Keefe, J. R.

1981-01-01

The potential effects of spaceflight on the processes of mammalian fertilizaton, implantation and embryonic development are investigated. Five female and two male rats were placed together on Day 2 of the flight. By R+17, it was determined that both flight and synchronous females were not carrying normal pregnancies and three of the flight animals were laparotomized. The uterus and ovaries were processed for microscopic analyses. The two remaining flight females were allowed to recover from the exploratory operation, rebred with flight males and delivered normal litters. As a control for potential transplacental effects that might be interpreted as direct spaceflight effects, a series of fertilized Japanese quail (Coturnix japonica) eggs was flown on Cosmos 1129. Although all of the eggs were adversely impacted by an inflight failure of the incubator humidifier on flight Day 13, several embryos were able to progress to a developmental stage equivalent to that of a control 10-12 Day embryo.

Host-pathogen interactions between the human innate immune system and Candida albicans—understanding and modeling defense and evasion strategies

PubMed Central

Dühring, Sybille; Germerodt, Sebastian; Skerka, Christine; Zipfel, Peter F.; Dandekar, Thomas; Schuster, Stefan

2015-01-01

The diploid, polymorphic yeast Candida albicans is one of the most important human pathogenic fungi. C. albicans can grow, proliferate and coexist as a commensal on or within the human host for a long time. However, alterations in the host environment can render C. albicans virulent. In this review, we describe the immunological cross-talk between C. albicans and the human innate immune system. We give an overview in form of pairs of human defense strategies including immunological mechanisms as well as general stressors such as nutrient limitation, pH, fever etc. and the corresponding fungal response and evasion mechanisms. Furthermore, Computational Systems Biology approaches to model and investigate these complex interactions are highlighted with a special focus on game-theoretical methods and agent-based models. An outlook on interesting questions to be tackled by Systems Biology regarding entangled defense and evasion mechanisms is given. PMID:26175718

A Framework for Understanding the Evasion of Host Immunity by Candida Biofilms

PubMed Central

Garcia-Perez, Josselyn E.; Mathé, Lotte; Humblet-Baron, Stephanie; Braem, Annabel; Lagrou, Katrien; Van Dijck, Patrick; Liston, Adrian

2018-01-01

Candida biofilms are a major cause of nosocomial morbidity and mortality. The mechanism by which Candida biofilms evade the immune system remains unknown. In this perspective, we develop a theoretical framework of the three, not mutually exclusive, models, which could explain biofilm evasion of host immunity. First, biofilms may exhibit properties of immunological silence, preventing immune activation. Second, biofilms may produce immune-deviating factors, converting effective immunity into ineffective immunity. Third, biofilms may resist host immunity, which would otherwise be effective. Using a murine subcutaneous biofilm model, we found that mice infected with biofilms developed sterilizing immunity effective when challenged with yeast form Candida. Despite the induction of effective anti-Candida immunity, no spontaneous clearance of the biofilm was observed. These results support the immune resistance model of biofilm immune evasion and demonstrate an asymmetric relationship between the host and biofilms, with biofilms eliciting effective immune responses yet being resistant to immunological clearance. PMID:29616035

Morphology of seahorse head hydrodynamically aids in capture of evasive prey.

PubMed

Gemmell, Brad J; Sheng, Jian; Buskey, Edward J

2013-01-01

Syngnathid fish (seahorses, pipefish and sea dragons) are slow swimmers yet capture evasive prey (copepods) using a technique known as the 'pivot' feeding, which involves rapid movement to overcome prey escape capabilities. However, this feeding mode functions only at short range and requires approaching very closely to hydrodynamically sensitive prey without triggering an escape. Here we investigate the role of head morphology on prey capture using holographic and particle image velocimetry (PIV). We show that head morphology functions to create a reduced fluid deformation zone, minimizing hydrodynamic disturbance where feeding strikes occur (above the end of the snout), and permits syngnathid fish to approach highly sensitive copepod prey (Acartia tonsa) undetected. The results explain how these animals can successfully employ short range 'pivot' feeding effectively on evasive prey. The need to approach prey with stealth may have selected for a head shape that produces lower deformation rates than other fish.

Mechanisms of immune evasion and current status of checkpoint inhibitors in non-small cell lung cancer.

PubMed

Qin, Angel; Coffey, David G; Warren, Edus H; Ramnath, Nithya

2016-09-01

In the past several years, immunotherapy has emerged as a viable treatment option for patients with advanced non-small cell lung cancer (NSCLC) without actionable driver mutations that have progressed on standard chemotherapy. We are also beginning to understand the methods of immune evasion employed by NSCLC which likely contribute to the 20% response rate to immunotherapy. It is also yet unclear what tumor or patient factors predict response to immunotherapy. The objectives of this review are (1) review the immunogenicity of NSCLC (2) describe the mechanisms of immune evasion (3) summarize efforts to target the anti-program death-1 (PD-1) and anti-program death-ligand 1(PD-L1) pathway (4) outline determinants of response to PD-1/PD-L1 therapy and (5) discuss potential future areas for research. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

14 CFR 21.37 - Flight test pilot.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight test pilot. 21.37 Section 21.37... PROCEDURES FOR PRODUCTS AND PARTS Type Certificates § 21.37 Flight test pilot. Each applicant for a normal... holding an appropriate pilot certificate to make the flight tests required by this part. [Doc. No. 5085...

14 CFR 21.37 - Flight test pilot.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flight test pilot. 21.37 Section 21.37... PROCEDURES FOR PRODUCTS AND PARTS Type Certificates § 21.37 Flight test pilot. Each applicant for a normal... holding an appropriate pilot certificate to make the flight tests required by this part. [Doc. No. 5085...

14 CFR 21.37 - Flight test pilot.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight test pilot. 21.37 Section 21.37... PROCEDURES FOR PRODUCTS AND PARTS Type Certificates § 21.37 Flight test pilot. Each applicant for a normal... holding an appropriate pilot certificate to make the flight tests required by this part. [Doc. No. 5085...

The Flight Anxiety Situations Questionnaire and the Flight Anxiety Modality Questionnaire: norms for people with fear of flying.

PubMed

Nousi, Aikaterini; van Gerwen, Lucas; Spinhoven, Philip

2008-09-01

The Flight Anxiety Situations Questionnaire (FAS) and the Flight Anxiety Modality Questionnaire (FAM) are widely used in clinical practice and research studies. The aim of this study was to derive norms for people suffering from fear of flying completing the FAS and FAM. The sample is composed of 2072 individuals suffering from fear of flying and 1012 non-patients. Means, standard deviations and percentile ranks for raw FAS and FAM subscale scores will be presented. Normative data are provided enabling the comparison of individual scores. The results showed a conspicuous difference between the patient and non-patient samples. As a whole the patient group scored higher on the scale assessing the level of anxiety experienced in different flight or flight-related situations and on the scale measuring the symptoms of anxiety or anticipatory anxiety in flight situations than the normal controls. The findings of this study suggest that the FAS and FAM questionnaires can be applied in the investigation of fearful flyers and the normal population. A considerable number of flying phobics obtained scores in the clinically significant range on the subscales assessing anticipatory anxiety, in-flight anxiety, generalized flight anxiety, somatic complaints and cognitive complaints.

Survival, Evasion, and Recovery Multiservice Procedures for Survival, Evasion and Recovery

DTIC Science & Technology

1999-06-01

Edible portions growing above ground that can be washed and peeled or skinned ( bananas , apples, etc.). • Smooth skinned vegetables, fruits, or above...environment. b. Leave only when (1) Dictated by the threat. (2) Are certain of your location, have a known destination, and have the ability to get there. (3...injured/uninjured condition. Adjust estimation of distance traveled against these factors to get relative accuracy when using a pace count. (4) Deliberate

Pursit-evasion game analysis in a line of sight coordinate system

NASA Technical Reports Server (NTRS)

Shinar, J.; Davidovitz, A.

1985-01-01

The paper proposes to use line of sight coordinates for the analysis of pursuit-evasion games. The advantage of this method for two-target games is shown to be evident. As a demonstrative example the game of two identical cars is formulated and solved in such coordinate systems. A new type of singular surface, overlooked in a previous study of the same problem, is discovered as a consequence of the simplicity of the solution.

Was there significant tax evasion after the 1999 50 cent per pack cigarette tax increase in California?

PubMed Central

Emery, S; White, M; Gilpin, E; Pierce, J

2002-01-01

Objectives: Several states, including California, have implemented large cigarette excise tax increases, which may encourage smokers to purchase their cigarettes in other lower taxed states, or from other lower or non-taxed sources. Such tax evasion thwarts tobacco control objectives and may cost the state substantial tax revenues. Thus, this study investigates the extent of tax evasion in the 6–12 months after the implementation of California's $0.50/pack excise tax increase. Design and setting: Retrospective data analysis from the 1999 California Tobacco Surveys (CTS), a random digit dialled telephone survey of California households. Main outcome measures: Sources of cigarettes, average daily cigarette consumption, and reported price paid. Results: Very few (5.1 (0.7)% (±95% confidence limits)) of California smokers avoided the excise tax by usually purchasing cigarettes from non- or lower taxed sources, such as out-of-state outlets, military commissaries, or the internet. The vast majority of smokers purchased their cigarettes from the most convenient and expensive sources: convenience stores/gas (petrol) stations (45.0 (1.9)%), liquor/drug stores (16.4 (1.6)%), and supermarkets (8.8 (1.2)%). Conclusions: Despite the potential savings, tax evasion by individual smokers does not appear to pose a serious threat to California's excise tax revenues or its tobacco control objectives. PMID:12035006

A gas-tracer injection for evaluating the fate of methane in a coastal plain stream: Degassing versus in-stream oxidation

USGS Publications Warehouse

Heilweil, Victor M.; Solomon, D. Kip; Darrah, Thomas H.; Gilmore, Troy E.; Genereux, David P.

2016-01-01

Methane emissions from streams and rivers have recently been recognized as an important component of global greenhouse budgets. Stream methane is lost as evasion to the atmosphere or in-stream methane oxidation. Previous studies have quantified evasion and oxidation with point-scale measurements. In this study, dissolved gases (methane, krypton) were injected into a coastal plain stream in North Carolina to quantify stream CH4 losses at the watershed scale. Stream-reach modeling yielded gas transfer and oxidation rate constants of 3.2 ± 0.5 and 0.5 ± 1.5 d–1, respectively, indicating a ratio of about 6:1. The resulting evasion and oxidation rates of 2.9 mmol m–2 d–1 and 1,140 nmol L–1 d–1, respectively, lie within ranges of published values. Similarly, the gas transfer velocity (K600) of 2.1 m d–1 is consistent with other gas tracer studies. This study illustrates the utility of dissolved-gas tracers for evaluating stream methane fluxes. In contrast to point measurements, this approach provides a larger watershed-scale perspective. Further work is needed to quantify the magnitude of these fluxes under varying conditions (e.g., stream temperature, nutrient load, gradient, flow rate) at regional and global scales before reliable bottom-up estimates of methane evasion can be determined at global scales.

Streptococcus pneumoniae PspC Subgroup Prevalence in Invasive Disease and Differences in Contribution to Complement Evasion.

PubMed

van der Maten, Erika; van den Broek, Bryan; de Jonge, Marien I; Rensen, Kim J W; Eleveld, Marc J; Zomer, Aldert L; Cremers, Amelieke J H; Ferwerda, Gerben; de Groot, Ronald; Langereis, Jeroen D; van der Flier, Michiel

2018-04-01

The pneumococcal capsular serotype is an important determinant of complement resistance and invasive disease potential, but other virulence factors have also been found to contribute. Pneumococcal surface protein C (PspC), a highly variable virulence protein that binds complement factor H to evade C3 opsonization, is divided into two subgroups: choline-bound subgroup I and LPxTG-anchored subgroup II. The prevalence of different PspC subgroups in invasive pneumococcal disease (IPD) and functional differences in complement evasion are unknown. The prevalence of PspC subgroups in IPD isolates was determined in a collection of 349 sequenced strains of Streptococcus pneumoniae isolated from adult patients. pspC deletion mutants and isogenic pspC switch mutants were constructed to study differences in factor H binding and complement evasion in relation to capsule thickness. Subgroup I pspC was far more prevalent in IPD isolates than subgroup II pspC The presence of capsule was associated with a greater ability of bound factor H to reduce complement opsonization. Pneumococcal subgroup I PspC bound significantly more factor H and showed more effective complement evasion than subgroup II PspC in isogenic encapsulated pneumococci. We conclude that variation in the PspC subgroups, independent of capsule serotypes, affects pneumococcal factor H binding and its ability to evade complement deposition. Copyright © 2018 American Society for Microbiology.

Methane emissions from a human-dominated lowland coastal river network (Shanghai, China)

NASA Astrophysics Data System (ADS)

Wang, D.; Yu, Z.

2017-12-01

Evasion of methane (CH4) in streams and rivers play a critical role in global carbon (C) cycle, offsetting the C uptake by terrestrial ecosystems. However, little is known about CH4 emissions from lowland coastal rivers profoundly modified by anthropogenic perturbations. Here, we report results from a long-term, large-scale study of CH4 partial pressures (pCH4) and evasion rates in the Shanghai river network. The spatiotemporal variability of pCH4 was examined along a land-use gradient and the annual CH4 evasion were estimated to assess its role in regional C budget. During the study period, the median pCH4 from 87 surveyed rivers was 241 μatm. CH4 was oversaturated throughout the river network, CH4 hotpots were concentrated in the small urban rivers and highly discharge-dependent. The annual median fCH4 for each site ranged from 3.1 mg C•m-2•d-1 to 296.6 mg C•m-2•d-1. The annual CH4 evasion were 105 Gg CO2-eq•yr-1 and 96 Gg CO2-eq•yr-1 for the entire river network and the mainland rivers, respectively. Given the rapid urbanization in global coastal areas, more research is needed to quantify the role of lowland coastal rivers as a major landscape C source in global C budget.

The cost of assuming the life history of a host: acoustic startle in the parasitoid fly Ormia ochracea

PubMed Central

Rosen, M. J.; Levin, E. C.; Hoy, R. R.

2009-01-01

In the obligatory reproductive dependence of a parasite on its host, the parasite must trade the benefit of ‘outsourcing’ functions like reproduction for the risk of assuming hazards associated with the host. In the present study, we report behavioral adaptations of a parasitic fly, Ormia ochracea, that resemble those of its cricket hosts. Ormia females home in on the male cricket's songs and deposit larvae, which burrow into the cricket, feed and emerge to pupate. Because male crickets call at night, gravid female Ormia in search of hosts are subject to bat predation, in much the same way as female crickets are when responding to male song. We show that Ormia has evolved the same evasive behavior as have crickets: an acoustic startle response to bat-like ultrasound that manifests clearly only during flight. Furthermore, like crickets, Ormia has a sharp response boundary between the frequencies of song and bat cries, resembling categorical perception first described in the context of human speech. PMID:19946084

Obstacle Detection Algorithms for Rotorcraft Navigation

NASA Technical Reports Server (NTRS)

Kasturi, Rangachar; Camps, Octavia I.; Huang, Ying; Narasimhamurthy, Anand; Pande, Nitin; Ahumada, Albert (Technical Monitor)

2001-01-01

In this research we addressed the problem of obstacle detection for low altitude rotorcraft flight. In particular, the problem of detecting thin wires in the presence of image clutter and noise was studied. Wires present a serious hazard to rotorcrafts. Since they are very thin, their detection early enough so that the pilot has enough time to take evasive action is difficult, as their images can be less than one or two pixels wide. After reviewing the line detection literature, an algorithm for sub-pixel edge detection proposed by Steger was identified as having good potential to solve the considered task. The algorithm was tested using a set of images synthetically generated by combining real outdoor images with computer generated wire images. The performance of the algorithm was evaluated both, at the pixel and the wire levels. It was observed that the algorithm performs well, provided that the wires are not too thin (or distant) and that some post processing is performed to remove false alarms due to clutter.

The cost of assuming the life history of a host: acoustic startle in the parasitoid fly Ormia ochracea.

PubMed

Rosen, M J; Levin, E C; Hoy, R R

2009-12-01

In the obligatory reproductive dependence of a parasite on its host, the parasite must trade the benefit of 'outsourcing' functions like reproduction for the risk of assuming hazards associated with the host. In the present study, we report behavioral adaptations of a parasitic fly, Ormia ochracea, that resemble those of its cricket hosts. Ormia females home in on the male cricket's songs and deposit larvae, which burrow into the cricket, feed and emerge to pupate. Because male crickets call at night, gravid female Ormia in search of hosts are subject to bat predation, in much the same way as female crickets are when responding to male song. We show that Ormia has evolved the same evasive behavior as have crickets: an acoustic startle response to bat-like ultrasound that manifests clearly only during flight. Furthermore, like crickets, Ormia has a sharp response boundary between the frequencies of song and bat cries, resembling categorical perception first described in the context of human speech.

Experiment K305: Quantitative analysis of selected bone parameters. Supplement 2: Bone elongation rate and bone mass in metaphysis of long bones

NASA Technical Reports Server (NTRS)

Jee, W. S. S.; Kimmel, D. B.; Smith, C.; Dell, R. B.

1981-01-01

The proximal humeral metaphysis of rats from time periods recovery plus zero days (R+0), recovery plus six days (R+6), and recovery plus twenty nine days (R+29) was analyzed. The volume of calcified cartilage and bone in flight and synchronous controls was reduced in groups R+0 and R+6, but was normal in group R+29. The number of functional bone cells (osteoblasts and osteoclasts) was decreased in proportion to the amount of bone in the early groups, and was normal in the last group. The fatty marrow volume was increased only in flight animals of groups R+0 and R+6, but was normal in the R+29 group. Accumulation of excess fatty marrow was seen only in flight animals. The decreased amount of bone and calcified cartilage is believed to be the result of a temporarily slowed or arrested production of calcified cartilage as a substrate for bone formation. This would have resulted from slowed bone elongation during flight and synchronous control conditions. Bone elongation returned to normal by twenty nine days after return.

CMV immune evasion and manipulation of the immune system with aging.

PubMed

Jackson, Sarah E; Redeker, Anke; Arens, Ramon; van Baarle, Debbie; van den Berg, Sara P H; Benedict, Chris A; Čičin-Šain, Luka; Hill, Ann B; Wills, Mark R

2017-06-01

Human cytomegalovirus (HCMV) encodes numerous proteins and microRNAs that function to evade the immune response and allow the virus to replicate and disseminate in the face of a competent innate and acquired immune system. The establishment of a latent infection by CMV, which if completely quiescent at the level of viral gene expression would represent an ultimate in immune evasion strategies, is not sufficient for lifelong persistence and dissemination of the virus. CMV needs to reactivate and replicate in a lytic cycle of infection in order to disseminate further, which occurs in the face of a fully primed secondary immune response. Without reactivation, latency itself would be redundant for the virus. It is also becoming clear that latency is not a totally quiescent state, but is characterized by limited viral gene expression. Therefore, the virus also needs immune evasion strategies during latency. An effective immune response to CMV is required or viral replication will cause morbidity and ultimately mortality in the host. There is clearly a complex balance between virus immune evasion and host immune recognition over a lifetime. This poses the important question of whether long-term evasion or manipulation of the immune response driven by CMV is detrimental to health. In this meeting report, three groups used the murine model of CMV (MCMV) to examine if the contribution of the virus to immune senescence is set by the (i) initial viral inoculum, (ii) inflation of T cell responses, (iii) or the balance between functionally distinct effector CD4+ T cells. The work of other groups studying the CMV response in humans is discussed. Their work asks whether the ability to make immune responses to new antigens is compromised by (i) age and HCMV carriage, (ii) long-term exposure to HCMV giving rise to an overall immunosuppressive environment and increased levels of latent virus, or (iii) adapted virus mutants (used as potential vaccines) that have the capacity to elicit conventional and unconventional T cell responses.

Loss of function JAK1 mutations occur at high frequency in cancers with microsatellite instability and are suggestive of immune evasion.

PubMed

Albacker, Lee A; Wu, Jeremy; Smith, Peter; Warmuth, Markus; Stephens, Philip J; Zhu, Ping; Yu, Lihua; Chmielecki, Juliann

2017-01-01

Immune evasion is a well-recognized hallmark of cancer and recent studies with immunotherapy agents have suggested that tumors with increased numbers of neoantigens elicit greater immune responses. We hypothesized that the immune system presents a common selective pressure on high mutation burden tumors and therefore immune evasion mutations would be enriched in high mutation burden tumors. The JAK family of kinases is required for the signaling of a host of immune modulators in tumor, stromal, and immune cells. Therefore, we analyzed alterations in this family for the hypothesized signature of an immune evasion mutation. Here, we searched a database of 61,704 unique solid tumors for alterations in the JAK family kinases (JAK1/2/3, TYK2). We used The Cancer Genome Atlas and Cancer Cell Line Encyclopedia data to confirm and extend our findings by analyzing gene expression patterns. Recurrent frameshift mutations in JAK1 were associated with high mutation burden and microsatellite instability. These mutations occurred in multiple tumor types including endometrial, colorectal, stomach, and prostate carcinomas. Analyzing gene expression signatures in endometrial and stomach adenocarcinomas revealed that tumors with a JAK1 frameshift exhibited reduced expression of interferon response signatures and multiple anti-tumor immune signatures. Importantly, endometrial cancer cell lines exhibited similar gene expression changes that were expected to be tumor cell intrinsic (e.g. interferon response) but not those expected to be tumor cell extrinsic (e.g. NK cells). From these data, we derive two primary conclusions: 1) JAK1 frameshifts are loss of function alterations that represent a potential pan-cancer adaptation to immune responses against tumors with microsatellite instability; 2) The mechanism by which JAK1 loss of function contributes to tumor immune evasion is likely associated with loss of the JAK1-mediated interferon response.

The History of MIS-Y: U.S. Strategic Interrogation During World War II

DTIC Science & Technology

2002-08-01

27Ian Dear, Escape and Evasion, (London, UK: Arms and Armour Press, 1997), 11. 28Lloyd R. Shoemaker, The Escape Factory (New York: St. Martin’s...soldiers are beginning to understand that they are the underdogs carrying the weight of the bureaucracy. 11. Building up the Nazi Gangster Ideal. In...and Evasion: Prisoner of War Breakouts and the Routes to Safety in World War Two. New York: Arms and Armour Press, 1997. DeForest, Orrin, and David

Why Does Mptcp Have To Make Things So Complicated : Cross Path Nids Evasion And Countermeasures

DTIC Science & Technology

2016-09-01

previously only establish communication channels over single network paths to communicate over multiple network paths. MPTCP is an enhancement toTCP that...the attacker would fail to create a Command and Control (C2) channel unless the attacker had created a new mapping to the target on the splicing...machine. This would allow the attacker to conduct C2 over a spliced channel . This may even make the attacker’s C2 more evasive. In fact, the effect

Spirochetal Lipoproteins and Immune Evasion

PubMed Central

Christodoulides, Alexei; Boyadjian, Ani; Kelesidis, Theodoros

2017-01-01

Spirochetes are a major threat to public health. However, the exact pathogenesis of spirochetal diseases remains unclear. Spirochetes express lipoproteins that often determine the cross talk between the host and spirochetes. Lipoproteins are pro-inflammatory, modulatory of immune responses, and enable the spirochetes to evade the immune system. In this article, we review the modulatory effects of spirochetal lipoproteins related to immune evasion. Understanding lipoprotein-induced immunomodulation will aid in elucidating innate pathogenesis processes and subsequent adaptive mechanisms potentially relevant to spirochetal disease vaccine development and treatment. PMID:28424696

Columbia: The first five flights entry heating data series. Volume 4: The lower windward wing 50 percent and 80 percent semispans

NASA Technical Reports Server (NTRS)

Williams, S. D.

1983-01-01

Entry heating flight data and wind tunnel data on the lower wing 50% and 80% Semi-Spans are presented for the first five flights of the Space Shuttle Orbiter. The heating rate data is presented in terms of normalized film heat transfer coefficients as a function of angle-of-attack, Mach number, and Normal Shock Reynolds number. The surface heating rates and temperatures were obtained via the JSC NONLIN/INVERSE computer program. Time history plots of the surface heating rates and temperatures are also presented.

Negative Selection Algorithm for Aircraft Fault Detection

NASA Technical Reports Server (NTRS)

Dasgupta, D.; KrishnaKumar, K.; Wong, D.; Berry, M.

2004-01-01

We investigated a real-valued Negative Selection Algorithm (NSA) for fault detection in man-in-the-loop aircraft operation. The detection algorithm uses body-axes angular rate sensory data exhibiting the normal flight behavior patterns, to generate probabilistically a set of fault detectors that can detect any abnormalities (including faults and damages) in the behavior pattern of the aircraft flight. We performed experiments with datasets (collected under normal and various simulated failure conditions) using the NASA Ames man-in-the-loop high-fidelity C-17 flight simulator. The paper provides results of experiments with different datasets representing various failure conditions.

Vitamin D metabolites and bioactive parathyroid hormone levels during Spacelab 2

NASA Technical Reports Server (NTRS)

Morey-Holton, Emily R.; Schnoes, Heinrich K.; Deluca, Hector F.; Phelps, Mary E.; Klein, Robert F.

1988-01-01

The effect of an 8-day space flight (Spacelab mission 2) on plasma levels of the vitamin D and parathyroid hormones is investigated experimentally in four crew members. The results are presented in tables and graphs and briefly characterized. Parathyroid hormone levels remained normal throughout the flight, whereas vitamin D hormone levels increased significantly on day 1 but returned to normal by day 7.

14 CFR 65.55 - Knowledge requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... meteorological conditions in the National Airspace System; (8) Air traffic control procedures and pilot... aircraft's flight characteristics and performance in normal and abnormal flight regimes; (11) Human factors...

14 CFR 61.155 - Aeronautical knowledge.

Code of Federal Regulations, 2013 CFR

2013-01-01

... meteorological conditions in the National Airspace System; (8) Air traffic control procedures and pilot... aircraft's flight characteristics and performance in normal and abnormal flight regimes; (11) Human factors...

14 CFR 91.1101 - Pilots: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2014 CFR

2014-01-01

... consumption and cruise control; (9) Flight planning; (10) Each normal and emergency procedure; and (11) The..., DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT... manager's flight locating procedures; (2) Principles and methods for determining weight and balance, and...

14 CFR 91.1101 - Pilots: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2013 CFR

2013-01-01

... consumption and cruise control; (9) Flight planning; (10) Each normal and emergency procedure; and (11) The..., DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT... manager's flight locating procedures; (2) Principles and methods for determining weight and balance, and...

14 CFR 91.1101 - Pilots: Initial, transition, and upgrade ground training.

Code of Federal Regulations, 2012 CFR

2012-01-01

... consumption and cruise control; (9) Flight planning; (10) Each normal and emergency procedure; and (11) The..., DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT... manager's flight locating procedures; (2) Principles and methods for determining weight and balance, and...

Tax Compliance Inventory: TAX-I Voluntary tax compliance, enforced tax compliance, tax avoidance, and tax evasion

PubMed Central

Kirchler, Erich; Wahl, Ingrid

2010-01-01

Surveys on tax compliance and non-compliance often rely on ad hoc formulated items which lack standardization and empirical validation. We present an inventory to assess tax compliance and distinguish between different forms of compliance and non-compliance: voluntary versus enforced compliance, tax avoidance, and tax evasion. First, items to measure voluntary and enforced compliance, avoidance, and evasion were drawn up (collected from past research and newly developed), and tested empirically with the aim of producing four validated scales with a clear factorial structure. Second, findings from the first analyses were replicated and extended to validation on the basis of motivational postures. A standardized inventory is provided which can be used in surveys in order to collect data which are comparable across research focusing on self-reports. The inventory can be used in either of two ways: either in its entirety, or by applying the single scales independently, allowing an economical and fast assessment of different facets of tax compliance. PMID:20502612

Supply Chain-based Solution to Prevent Fuel Tax Evasion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franzese, Oscar; Capps, Gary J; Daugherty, Michael

The primary source of funding for the United States transportation system is derived from motor fuel and other highway use taxes. Loss of revenue attributed to fuel-tax evasion has been assessed to be somewhere between $1 billion per year, or approximately 25% of the total tax collected. Any solution that addresses this problem needs to include not only the tax-collection agencies and auditors, but also the carriers transporting oil products and the carriers customers. This paper presents a system developed by the Oak Ridge National Laboratory for the Federal Highway Administration which has the potential to reduce or eliminate manymore » fuel-tax evasion schemes. The solution balances the needs of tax-auditors and those of the fuel-hauling companies and their customers. The technology was deployed and successfully tested during an eight-month period on a real-world fuel-hauling fleet. Day-to-day operations of the fleet were minimally affected by their interaction with this system. The results of that test are discussed in this paper.« less

Structure and mechanism of a molecular rheostat, an RNA thermometer that modulates immune evasion by Neisseria meningitidis

PubMed Central

Barnwal, Ravi Pratap; Loh, Edmund; Godin, Katherine S.; Yip, Jordan; Lavender, Hayley; Tang, Christoph M.; Varani, Gabriele

2016-01-01

Neisseria meningitidis causes bacterial meningitis and septicemia. It evades the host complement system by upregulating expression of immune evasion factors in response to changes in temperature. RNA thermometers within mRNAs control expression of bacterial immune evasion factors, including CssA, in the 5′-untranslated region of the operon for capsule biosynthesis. We dissect the molecular mechanisms of thermoregulation and report the structure of the CssA thermometer. We show that the RNA thermometer acts as a rheostat, whose stability is optimized to respond in a small temperature range around 37°C as occur within the upper airways during infection. Small increases in temperature gradually open up the structure to allow progressively increased access to the ribosome binding site. Even small changes in stability induced by mutations of imperfect base pairs, as in naturally occurring polymorphisms, shift the thermometer response outside of the desired temperature range, suggesting that its activity could be modulated by pharmacological intervention. PMID:27369378

Signaling pathways and immune evasion mechanisms in classical Hodgkin lymphoma.

PubMed

Liu, W Robert; Shipp, Margaret A

2017-11-23

Classical Hodgkin lymphoma (cHL) is an unusual B-cell-derived malignancy in which rare malignant Hodgkin and Reed-Sternberg (HRS) cells are surrounded by an extensive but ineffective inflammatory/immune cell infiltrate. This striking feature suggests that malignant HRS cells escape immunosurveillance and interact with immune cells in the cancer microenvironment for survival and growth. We previously found that cHLs have a genetic basis for immune evasion: near-uniform copy number alterations of chromosome 9p24.1 and the associated PD-1 ligand loci, CD274/PD-L1 and PDCD1LG2/PD-L2, and copy number-dependent increased expression of these ligands. HRS cells expressing PD-1 ligands are thought to engage PD-1 receptor-positive immune effectors in the tumor microenvironment and induce PD-1 signaling and associated immune evasion. The genetic bases of enhanced PD-1 signaling in cHL make these tumors uniquely sensitive to PD-1 blockade. © 2017 by The American Society of Hematology.

[Regulatory Mechanisms of PD-L1 Expression and Its Role in Immune Evasion].

PubMed

Kataoka, Keisuke

2017-11-01

Immune checkpoint blockade therapy using anti-PD-1 or anti-PD-L1 antibodies can unleash anti-tumor immunity and induce durable remission in a variety ofhuman cancers. However, the regulatory mechanisms of PD-L1 expression mediating immune evasion ofcancer cells have not been fully elucidated, including the genetic alterations causing PD-L1 overexpression. Recently, we have reported a novel genetic mechanism ofimmune evasion associated with structural variations(SVs)disrupting the 3'-untranslated region(UTR)ofthe PD-L1 gene in various malignancies, such as aggressive lymphomas and gastrointestinal cancers. Despite a heterogenous nature ofthese SVs, they are closely associated with a marked upregulation of PD-L1 expression, which augments tumor growth and escape from anti-tumor immunity. Here we present an overview of the regulatory mechanisms of PD-L1 expression in cancer cells, highlighting the genetic mechanisms of PD-L1 constitutive activation, with specific focus on PD-L1 3'-UTR disruption.

An MHC class I immune evasion gene of Marek׳s disease virus.

PubMed

Hearn, Cari; Preeyanon, Likit; Hunt, Henry D; York, Ian A

2015-01-15

Marek׳s disease virus (MDV) is a widespread α-herpesvirus of chickens that causes T cell tumors. Acute, but not latent, MDV infection has previously been shown to lead to downregulation of cell-surface MHC class I (Virology 282:198-205 (2001)), but the gene(s) involved have not been identified. Here we demonstrate that an MDV gene, MDV012, is capable of reducing surface expression of MHC class I on chicken cells. Co-expression of an MHC class I-binding peptide targeted to the endoplasmic reticulum (bypassing the requirement for the TAP peptide transporter) partially rescued MHC class I expression in the presence of MDV012, suggesting that MDV012 is a TAP-blocking MHC class I immune evasion protein. This is the first unique non-mammalian MHC class I immune evasion gene identified, and suggests that α-herpesviruses have conserved this function for at least 100 million years. Copyright © 2014 Elsevier Inc. All rights reserved.

Immune Evasion Strategies and Persistence of Helicobacter pylori.

PubMed

Mejías-Luque, Raquel; Gerhard, Markus

Helicobacter pylori infection is commonly acquired during childhood, can persist lifelong if not treated, and can cause different gastric pathologies, including chronic gastritis, peptic ulcer disease, and eventually gastric cancer. H. pylori has developed a number of strategies in order to cope with the hostile conditions found in the human stomach as well as successful mechanisms to evade the strong innate and adaptive immune responses elicited upon infection. Thus, by manipulating innate immune receptors and related signaling pathways, inducing tolerogenic dendritic cells and inhibiting effector T cell responses, H. pylori ensures low recognition by the host immune system as well as its persistence in the gastric epithelium. Bacterial virulence factors such as cytotoxin-associated gene A, vacuolating cytotoxin A, or gamma-glutamyltranspeptidase have been extensively studied in the context of bacterial immune escape and persistence. Further, the bacterium possesses other factors that contribute to immune evasion. In this chapter, we discuss in detail the main evasion and persistence strategies evolved by the bacterium as well as the specific bacterial virulence factors involved.

Tax Compliance Inventory: TAX-I Voluntary tax compliance, enforced tax compliance, tax avoidance, and tax evasion.

PubMed

Kirchler, Erich; Wahl, Ingrid

2010-06-01

Surveys on tax compliance and non-compliance often rely on ad hoc formulated items which lack standardization and empirical validation. We present an inventory to assess tax compliance and distinguish between different forms of compliance and non-compliance: voluntary versus enforced compliance, tax avoidance, and tax evasion. First, items to measure voluntary and enforced compliance, avoidance, and evasion were drawn up (collected from past research and newly developed), and tested empirically with the aim of producing four validated scales with a clear factorial structure. Second, findings from the first analyses were replicated and extended to validation on the basis of motivational postures. A standardized inventory is provided which can be used in surveys in order to collect data which are comparable across research focusing on self-reports. The inventory can be used in either of two ways: either in its entirety, or by applying the single scales independently, allowing an economical and fast assessment of different facets of tax compliance.

A versatile assay to determine bacterial and host factors contributing to opsonophagocytotic killing in hirudin-anticoagulated whole blood.

PubMed

van der Maten, Erika; de Jonge, Marien I; de Groot, Ronald; van der Flier, Michiel; Langereis, Jeroen D

2017-02-08

Most bacteria entering the bloodstream will be eliminated through complement activation on the bacterial surface and opsonophagocytosis. However, when these protective innate immune systems do not work optimally, or when bacteria are equipped with immune evasion mechanisms that prevent killing, this can lead to serious infections such as bacteremia and meningitis, which is associated with high morbidity and mortality. In order to study the complement evasion mechanisms of bacteria and the capacity of human blood to opsonize and kill bacteria, we developed a versatile whole blood killing assay wherein both phagocyte function and complement activity can easily be monitored and modulated. In this assay we use a selective thrombin inhibitor hirudin to fully preserve complement activity of whole blood. This assay allows controlled analysis of the requirements for active complement by replacing or heat-inactivating plasma, phagocyte function and bacterial immune evasion mechanisms that contribute to survival in human blood.

A versatile assay to determine bacterial and host factors contributing to opsonophagocytotic killing in hirudin-anticoagulated whole blood

PubMed Central

van der Maten, Erika; de Jonge, Marien I.; de Groot, Ronald; van der Flier, Michiel; Langereis, Jeroen D.

2017-01-01

Most bacteria entering the bloodstream will be eliminated through complement activation on the bacterial surface and opsonophagocytosis. However, when these protective innate immune systems do not work optimally, or when bacteria are equipped with immune evasion mechanisms that prevent killing, this can lead to serious infections such as bacteremia and meningitis, which is associated with high morbidity and mortality. In order to study the complement evasion mechanisms of bacteria and the capacity of human blood to opsonize and kill bacteria, we developed a versatile whole blood killing assay wherein both phagocyte function and complement activity can easily be monitored and modulated. In this assay we use a selective thrombin inhibitor hirudin to fully preserve complement activity of whole blood. This assay allows controlled analysis of the requirements for active complement by replacing or heat-inactivating plasma, phagocyte function and bacterial immune evasion mechanisms that contribute to survival in human blood. PMID:28176849

Viral mimicry of cytokines, chemokines and their receptors.

PubMed

Alcami, Antonio

2003-01-01

Viruses have evolved elegant mechanisms to evade detection and destruction by the host immune system. One of the evasion strategies that have been adopted by large DNA viruses is to encode homologues of cytokines, chemokines and their receptors--molecules that have a crucial role in control of the immune response. Viruses have captured host genes or evolved genes to target specific immune pathways, and so viral genomes can be regarded as repositories of important information about immune processes, offering us a viral view of the host immune system. The study of viral immunomodulatory proteins might help us to uncover new human genes that control immunity, and their characterization will increase our understanding of not only viral pathogenesis, but also normal immune mechanisms. Moreover, viral proteins indicate strategies of immune modulation that might have therapeutic potential.

Predator evasion by white-tailed deer fawns

USGS Publications Warehouse

Grovenburg, Troy W.; Monteith, Kevin L.; Klaver, Robert W.; Jenks, Jonathan A.

2012-01-01

Despite their importance for understanding predator–prey interactions, factors that affect predator evasion behaviours of offspring of large ungulates are poorly understood. Our objective was to characterize the influence of selection and availability of escape cover and maternal presence on predator evasion by white-tailed deer, Odocoileus virginianus, fawns in the northern Great Plains, U.S.A. We observed 45 coyote, Canis latrans, chases of fawns, and we participated in 83 human chases of fawns during 2007–2009, of which, 19 and 42 chases, respectively, ended with capture of the fawn. Evasive techniques used by fawns were similar for human and coyote chases. Likelihood of a white-tailed deer fawn escaping capture, however, was influenced by deer group size and a number of antipredator behaviours, including aggressive defence by females, initial habitat and selection of escape cover, all of which were modified by the presence of parturient females. At the initiation of a chase, fawns in grasslands were more likely to escape, whereas fawns in forested cover, cultivated land or wheat were more likely to be captured by a coyote or human. Fawns fleeing to wetlands and grasslands also were less likely to be captured compared with those choosing forested cover, wheat and cultivated land. Increased probability of capture was associated with greater distance to wetland and grassland habitats and decreased distance to wheat. Use of wetland habitat as a successful antipredator strategy highlights the need for a greater understanding of the importance of habitat complexity in predator avoidance.

The p36 isoform of murine cytomegalovirus m152 protein suffices for mediating innate and adaptive immune evasion.

PubMed

Fink, Annette; Renzaho, Angeliqué; Reddehase, Matthias J; Lemmermann, Niels A W

2013-12-16

The MHC-class I (MHC-I)-like viral (MHC-Iv) m152 gene product of murine cytomegalovirus (mCMV) was the first immune evasion molecule described for a member of the β-subfamily of herpesviruses as a paradigm for analogous functions of human cytomegalovirus proteins. Notably, by interacting with classical MHC-I molecules and with MHC-I-like RAE1 family ligands of the activatory natural killer (NK) cell receptor NKG2D, it inhibits presentation of antigenic peptides to CD8 T cells and the NKG2D-dependent activation of NK cells, respectively, thus simultaneously interfering with adaptive and innate immune recognition of infected cells. Although the m152 gene product exists in differentially glycosylated isoforms whose individual contributions to immune evasion are unknown, it has entered the scientific literature as m152/gp40, based on the quantitatively most prominent isoform but with no functional justification. By construction of a recombinant mCMV in which all three N-glycosylation sites are mutated (N61Q, N208Q, and N241Q), we show here that N-linked glycosylation is not essential for functional interaction of the m152 immune evasion protein with either MHC-I or RAE1. These data add an important functional detail to recent structural analysis of the m152/RAE1g complex that has revealed N-glycosylations at positions Asn61 and Asn208 of m152 distant from the m152/RAE1g interface.

The role of feeding morphology and competition in governing the diet breadth of sympatric stomatopod crustaceans.

PubMed

deVries, Maya S

2017-04-01

Competition for food drives divergence and specialization in feeding morphology. Stomatopod crustaceans have two kinds of highly specialized feeding appendages: either elongate spear-like appendages ( spearers ) used to ambush soft-bodied evasive prey or hammer-like appendages ( smashers ) that produce extremely high forces used both to break hard-shelled prey and to capture evasive prey. To evaluate associations between appendage type and feeding ecology, the diet of two small smasher and spearer species (size range: 21-27 mm) that co-occur were compared. Stable isotope analysis and the Bayesian mixing model MixSIAR were used to estimate the proportional contributions of prey types to the diet. Both species had relatively wide diets that included hard-shelled and soft-bodied prey, albeit in different proportions; the smasher consumed a greater proportion of hard-shelled prey, and the spearer consumed mostly soft-bodied prey. Appendage kinematics in stomatopods is known to scale linearly across species. These two small species may produce similar kinematics allowing them both to capture evasive prey and hammer hard-shelled prey, thereby widening their diets. Yet, the spearer species is more highly adept at capturing evasive prey, indicating that small spearers are stronger competitors for soft-bodied prey. These findings suggest that a smasher's ability to access hard prey reduced competition for soft prey, and therefore conferred an important benefit favouring the evolution of the impressive smashing strike. © 2017 The Author(s).

The Surface-Exposed Protein SntA Contributes to Complement Evasion in Zoonotic Streptococcus suis.

PubMed

Deng, Simin; Xu, Tong; Fang, Qiong; Yu, Lei; Zhu, Jiaqi; Chen, Long; Liu, Jiahui; Zhou, Rui

2018-01-01

Streptococcus suis is an emerging zoonotic pathogen causing streptococcal toxic shock like syndrome (STSLS), meningitis, septicemia, and even sudden death in human and pigs. Serious septicemia indicates this bacterium can evade the host complement surveillance. In our previous study, a functionally unknown protein SntA of S. suis has been identified as a heme-binding protein, and contributes to virulence in pigs. SntA can interact with the host antioxidant protein AOP2 and consequently inhibit its antioxidant activity. In the present study, SntA is identified as a cell wall anchored protein that functions as an important player in S. suis complement evasion. The C3 deposition and membrane attack complex (MAC) formation on the surface of sntA -deleted mutant strain Δ sntA are demonstrated to be significantly higher than the parental strain SC-19 and the complementary strain CΔ sntA . The abilities of anti-phagocytosis, survival in blood, and in vivo colonization of Δ sntA are obviously reduced. SntA can interact with C1q and inhibit hemolytic activity via the classical pathway. Complement activation assays reveal that SntA can also directly activate classical and lectin pathways, resulting in complement consumption. These two complement evasion strategies may be crucial for the pathogenesis of this zoonotic pathogen. Concerning that SntA is a bifunctional 2',3'-cyclic nucleotide 2'-phosphodiesterase/3'-nucleotidase in many species of Gram-positive bacteria, these complement evasion strategies may have common biological significance.

F-15 IFCS: Intelligent Flight Control System

NASA Technical Reports Server (NTRS)

Bosworth, John

2007-01-01

This viewgraph presentation describes the F-15 Intelligent Flight Control System (IFCS). The goals of this project include: 1) Demonstrate revolutionary control approaches that can efficiently optimize aircraft performance in both normal and failure conditions; and 2) Demonstrate advance neural network-based flight control technology for new aerospace systems designs.

14 CFR 27.161 - Trim control.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Trim control. 27.161 Section 27.161... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Flight Characteristics § 27.161 Trim control. The trim control— (a) Must trim any steady longitudinal, lateral, and collective control forces to zero in level flight...

Design and Flight Tests of an Adaptive Control System Employing Normal-Acceleration Command

NASA Technical Reports Server (NTRS)

McNeill, Water E.; McLean, John D.; Hegarty, Daniel M.; Heinle, Donovan R.

1961-01-01

An adaptive control system employing normal-acceleration command has been designed with the aid of an analog computer and has been flight tested. The design of the system was based on the concept of using a mathematical model in combination with a high gain and a limiter. The study was undertaken to investigate the application of a system of this type to the task of maintaining nearly constant dynamic longitudinal response of a piloted airplane over the flight envelope without relying on air data measurements for gain adjustment. The range of flight conditions investigated was between Mach numbers of 0.36 and 1.15 and altitudes of 10,000 and 40,000 feet. The final adaptive system configuration was derived from analog computer tests, in which the physical airplane control system and much of the control circuitry were included in the loop. The method employed to generate the feedback signals resulted in a model whose characteristics varied somewhat with changes in flight condition. Flight results showed that the system limited the variation in longitudinal natural frequency of the adaptive airplane to about half that of the basic airplane and that, for the subsonic cases, the damping ratio was maintained between 0.56 and 0.69. The system also automatically compensated for the transonic trim change. Objectionable features of the system were an exaggerated sensitivity of pitch attitude to gust disturbances, abnormally large pitch attitude response for a given pilot input at low speeds, and an initial delay in normal-acceleration response to pilot control at all flight conditions. The adaptive system chatter of +/-0.05 to +/-0.10 of elevon at about 9 cycles per second (resulting in a maximum airplane normal-acceleration response of from +/-0.025 g to +/- 0.035 g) was considered by the pilots to be mildly objectionable but tolerable.

Evasion of Immunity to Plasmodium falciparum: Rosettes of Blood Group A Impair Recognition of PfEMP1

PubMed Central

Moll, Kirsten; Palmkvist, Mia; Ch'ng, Junhong; Kiwuwa, Mpungu Steven; Wahlgren, Mats

2015-01-01

The ABO blood group antigens are expressed on erythrocytes but also on endothelial cells, platelets and serum proteins. Notably, the ABO blood group of a malaria patient determines the development of the disease given that blood group O reduces the probability to succumb in severe malaria, compared to individuals of groups A, B or AB. P. falciparum rosetting and sequestration are mediated by PfEMP1, RIFIN and STEVOR, expressed at the surface of the parasitized red blood cell (pRBC). Antibodies to these antigens consequently modify the course of a malaria infection by preventing sequestration and promoting phagocytosis of pRBC. Here we have studied rosetting P. falciparum and present evidence of an immune evasion mechanism not previously recognized. We find the accessibility of antibodies to PfEMP1 at the surface of the pRBC to be reduced when P. falciparum forms rosettes in blood group A RBC, as compared to group O RBC. The pRBC surrounds itself with tightly bound normal RBC that makes PfEMP1 inaccessible to antibodies and clearance by the immune system. Accordingly, pRBC of in vitro cloned P. falciparum devoid of ABO blood group dependent rosetting were equally well detected by anti-PfEMP1 antibodies, independent of the blood group utilized for their propagation. The pathogenic mechanisms underlying the severe forms of malaria may in patients of blood group A depend on the ability of the parasite to mask PfEMP1 from antibody recognition, in so doing evading immune clearance. PMID:26714011

Promotion of a cancer-like phenotype, through chronic exposure to inflammatory cytokines and hypoxia in a bronchial epithelial cell line model

PubMed Central

Baird, Anne-Marie; Gray, Steven G.; Richard, Derek J.; O’Byrne, Kenneth J.

2016-01-01

Globally, lung cancer accounts for approximately 20% of all cancer related deaths. Five-year survival is poor and rates have remained unchanged for the past four decades. There is an urgent need to identify markers of lung carcinogenesis and new targets for therapy. Given the recent successes of immune modulators in cancer therapy and the improved understanding of immune evasion by tumours, we sought to determine the carcinogenic impact of chronic TNF-α and IL-1β exposure in a normal bronchial epithelial cell line model. Following three months of culture in a chronic inflammatory environment under conditions of normoxia and hypoxia (0.5% oxygen), normal cells developed a number of key genotypic and phenotypic alterations. Important cellular features such as the proliferative, adhesive and invasive capacity of the normal cells were significantly amplified. In addition, gene expression profiles were altered in pathways associated with apoptosis, angiogenesis and invasion. The data generated in this study provides support that TNF-α, IL-1β and hypoxia promotes a neoplastic phenotype in normal bronchial epithelial cells. In turn these mediators may be of benefit for biomarker and/or immune-therapy target studies. This project provides an important inflammatory in vitro model for further immuno-oncology studies in the lung cancer setting. PMID:26759080

Interaction of compass sensing and object-motion detection in the locust central complex.

PubMed

Bockhorst, Tobias; Homberg, Uwe

2017-07-01

Goal-directed behavior is often complicated by unpredictable events, such as the appearance of a predator during directed locomotion. This situation requires adaptive responses like evasive maneuvers followed by subsequent reorientation and course correction. Here we study the possible neural underpinnings of such a situation in an insect, the desert locust. As in other insects, its sense of spatial orientation strongly relies on the central complex, a group of midline brain neuropils. The central complex houses sky compass cells that signal the polarization plane of skylight and thus indicate the animal's steering direction relative to the sun. Most of these cells additionally respond to small moving objects that drive fast sensory-motor circuits for escape. Here we investigate how the presentation of a moving object influences activity of the neurons during compass signaling. Cells responded in one of two ways: in some neurons, responses to the moving object were simply added to the compass response that had adapted during continuous stimulation by stationary polarized light. By contrast, other neurons disadapted, i.e., regained their full compass response to polarized light, when a moving object was presented. We propose that the latter case could help to prepare for reorientation of the animal after escape. A neuronal network based on central-complex architecture can explain both responses by slight changes in the dynamics and amplitudes of adaptation to polarized light in CL columnar input neurons of the system. NEW & NOTEWORTHY Neurons of the central complex in several insects signal compass directions through sensitivity to the sky polarization pattern. In locusts, these neurons also respond to moving objects. We show here that during polarized-light presentation, responses to moving objects override their compass signaling or restore adapted inhibitory as well as excitatory compass responses. A network model is presented to explain the variations of these responses that likely serve to redirect flight or walking following evasive maneuvers. Copyright © 2017 the American Physiological Society.

Spacecraft Design Thermal Control Subsystem

NASA Technical Reports Server (NTRS)

Miyake, Robert N.

2008-01-01

The Thermal Control Subsystem engineers task is to maintain the temperature of all spacecraft components, subsystems, and the total flight system within specified limits for all flight modes from launch to end-of-mission. In some cases, specific stability and gradient temperature limits will be imposed on flight system elements. The Thermal Control Subsystem of "normal" flight systems, the mass, power, control, and sensing systems mass and power requirements are below 10% of the total flight system resources. In general the thermal control subsystem engineer is involved in all other flight subsystem designs.

Columbia: The first 5 flights entry heating data series. Volume 5: The side fuselage and payload bay door

NASA Technical Reports Server (NTRS)

Williams, S. D.

1984-01-01

Entry heating flight data and wind tunnel data on the side fuselage and payload bay door, Z = 400 and 440 trace aft of X/L=0.2, for the first five flights of the Space Shuttle Orbiter are presented. The heating rate data are reviewed in terms of normalized film heat transfer coefficients as a function of angle of attack, Mach number, and normal shock Reynolds number. The surface heatings rates and temperatures were obtained by the JSC NONLIN/INVERSE computer program. Time history plots of the surface heating rates and temperatures are outlined.

Evasion of Influenza A Viruses from Innate and Adaptive Immune Responses

PubMed Central

van de Sandt, Carolien E.; Kreijtz, Joost H. C. M.; Rimmelzwaan, Guus F.

2012-01-01

The influenza A virus is one of the leading causes of respiratory tract infections in humans. Upon infection with an influenza A virus, both innate and adaptive immune responses are induced. Here we discuss various strategies used by influenza A viruses to evade innate immune responses and recognition by components of the humoral and cellular immune response, which consequently may result in reduced clearing of the virus and virus-infected cells. Finally, we discuss how the current knowledge about immune evasion can be used to improve influenza A vaccination strategies. PMID:23170167

The Effects of Target and Missile Characteristics on Theoretical Minimum Miss Distance for a Beam-Rider Guidance System in the Presence of Noise

NASA Technical Reports Server (NTRS)

Stewart, Elwood C.; Druding, Frank; Nishiura, Togo

1959-01-01

A study has been made to determine the relative importance of those factors which place an inherent limitation on the minimum obtainable miss distance for a beam-rider navigation system operating in the presence of glint noise and target evasive maneuver. Target and missile motions are assumed to be coplanar. The factors considered are the missile natural frequencies and damping ratios, missile steady-state acceleration capabilities, target evasive maneuver characteristics, and angular scintillation noise characteristics.

Low-speed wind-tunnel investigation of the flight dynamic characteristics of an advanced turboprop business/commuter aircraft configuration

NASA Technical Reports Server (NTRS)

Coe, Paul L., Jr.; Turner, Steven G.; Owens, D. Bruce

1990-01-01

An investigation was conducted to determine the low-speed flight dynamic behavior of a representative advanced turboprop business/commuter aircraft concept. Free-flight tests were conducted in the NASA Langley Research Center's 30- by 60-Foot Tunnel. In support of the free-flight tests, conventional static, dynamic, and free-to-roll oscillation tests were performed. Tests were intended to explore normal operating and post stall flight conditions, and conditions simulating the loss of power in one engine.

Animal behavior: fly flight moves forward.

PubMed

Fox, Jessica L; Frye, Mark

2013-04-08

A new study has resolved the paradox of how flies maintain reflexive aversion to your approaching swatter, whilst tolerating similar visual signals during normal forward flight. Copyright © 2013 Elsevier Ltd. All rights reserved.

14 CFR 91.519 - Passenger briefing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Large and Turbine-Powered Multiengine... flotation equipment required under § 91.509 for a flight over water; and (6) The normal and emergency use of...

14 CFR 91.519 - Passenger briefing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Large and Turbine-Powered Multiengine... flotation equipment required under § 91.509 for a flight over water; and (6) The normal and emergency use of...

14 CFR 91.519 - Passenger briefing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Large and Turbine-Powered Multiengine... flotation equipment required under § 91.509 for a flight over water; and (6) The normal and emergency use of...

14 CFR 91.519 - Passenger briefing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Large and Turbine-Powered Multiengine... flotation equipment required under § 91.509 for a flight over water; and (6) The normal and emergency use of...

14 CFR 91.519 - Passenger briefing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Large and Turbine-Powered Multiengine... flotation equipment required under § 91.509 for a flight over water; and (6) The normal and emergency use of...

Disruption of postural readaptation by inertial stimuli following space flight

NASA Technical Reports Server (NTRS)

Black, F. O.; Paloski, W. H.; Reschke, M. F.; Igarashi, M.; Guedry, F.; Anderson, D. J.

1999-01-01

Postural instability (relative to pre-flight) has been observed in all shuttle astronauts studied upon return from orbital missions. Postural stability was more closely examined in four shuttle astronaut subjects before and after an 8 day orbital mission. Results of the pre- and post-flight postural stability studies were compared with a larger (n = 34) study of astronauts returning from shuttle missions of similar duration. Results from both studies indicated that inadequate vestibular feedback was the most significant sensory deficit contributing to the postural instability observed post flight. For two of the four IML-1 astronauts, post-flight postural instability and rate of recovery toward their earth-normal performance matched the performance of the larger sample. However, post-flight postural control in one returning astronaut was substantially below mean performance. This individual, who was within normal limits with respect to postural control before the mission, indicated that recovery to pre-flight postural stability was also interrupted by a post-flight pitch plane rotation test. A similar, though less extreme departure from the mean recovery trajectory was present in another astronaut following the same post-flight rotation test. The pitch plane rotation stimuli included otolith stimuli in the form of both transient tangential and constant centripetal linear acceleration components. We inferred from these findings that adaptation on orbit and re-adaptation on earth involved a change in sensorimotor integration of vestibular signals most likely from the otolith organs.

The effects of space flight on some rat liver enzymes regulating carbohydrate and lipid metabolism

NASA Technical Reports Server (NTRS)

Abraham, S.; Lin, C. Y.; Klein, H. P.; Volkmann, C.

1981-01-01

The effects of space flight conditions on the activities of certain enzymes regulating carbohydrate and lipid metabolism in rat liver are investigated in an attempt to account for the losses in body weight observed during space flight despite preflight caloric consumption. Liver samples were analyzed for the activities of 32 cytosolic and microsomal enzymes as well as hepatic glycogen and individual fatty acid levels for ground control rats and rats flown on board the Cosmos 936 biosatellite under normal space flight conditions and in centrifuges which were sacrificed upon recovery or 25 days after recovery. Significant decreases in the activities of glycogen phosphorylase, alpha-glycerol phosphate acyl transferase, diglyceride acyl transferase, aconitase and 6-phosphogluconate dehydrogenase and an increase in palmitoyl CoA desaturase are found in the flight stationary relative to the flight contrifuged rats upon recovery, with all enzymes showing alterations returning to normal values 25 days postflight. The flight stationary group is also observed to be characterized by more than twice the amount of liver glycogen of the flight centrifuged group as well as a significant increase in the ratio of palmitic to palmitoleic acid. Results thus indicate metabolic changes which may be involved in the mechanism of weight loss during weightlessness, and demonstrate the equivalence of centrifugation during space flight to terrestrial gravity.

Predator-prey pursuit-evasion games in structurally complex environments.

PubMed

Morice, Sylvie; Pincebourde, Sylvain; Darboux, Frédéric; Kaiser, Wilfried; Casas, Jérôme

2013-11-01

Pursuit and evasion behaviors in many predator-prey encounters occur in a geometrically structured environment. The physical structures in the environment impose strong constraints on the perception and behavioral responses of both antagonists. Nevertheless, no experimental or theoretical study has tackled the issue of quantifying the role of the habitat's architecture on the joint trajectories during a predator-prey encounter. In this study, we report the influence of microtopography of forest leaf litter on the pursuit-evasion trajectories of wolf spiders Pardosa sp. attacking the wood cricket Nemobius sylvestris. Fourteen intact leaf litter samples of 1 m × 0.5 m were extracted from an oak-beech forest floor in summer and winter, with later samples having the most recently fallen leaves. Elevation was mapped at a spatial resolution of 0.5 mm using a laser scanner. Litter structuring patterns were identified by height transects and experimental semi-variograms. Detailed analysis of all visible leaf-fragments of one sample enabled us to relate the observed statistical patterns to the underlying geometry of individual elements. Video recording of pursuit-evasion sequences in arenas with flat paper or leaf litter enabled us to estimate attack and fleeing distances as a function of substrate. The compaction index, the length of contiguous flat surfaces, and the experimental variograms showed that the leaf litter was smoother in summer than in winter. Thus, weathering as well as biotic activities compacted and flattened the litter over time. We found good agreement between the size of the structuring unit of leaf litter and the distance over which attack and escape behaviors both were initiated (both ∼3 cm). There was a four-fold topographical effect on pursuit-escape sequences; compared with a flat surface, leaf litter (1) greatly reduced the likelihood of launching a pursuit, (2) reduced pursuit and escape distances by half, (3) put prey and predator on par in terms of pursuit and escape distances, and (4) reduced the likelihood of secondary pursuits, after initial escape of the prey, to nearly zero. Thus, geometry of the habitat strongly modulates the rules of pursuit-evasion in predator-prey interactions in the wild.

NASA Tech Briefs, February 2004

NASA Technical Reports Server (NTRS)

2004-01-01

Topics include: Simulation Testing of Embedded Flight Software; Improved Indentation Test for Measuring Nonlinear Elasticity; Ultraviolet-Absorption Spectroscopic Biofilm Monitor; Electronic Tongue for Quantitation of Contaminants in Water; Radar for Measuring Soil Moisture Under Vegetation; Modular Wireless Data-Acquisition and Control System; Microwave System for Detecting Ice on Aircraft; Routing Algorithm Exploits Spatial Relations; Two-Finger EKG Method of Detecting Evasive Responses; Updated System-Availability and Resource-Allocation Program; Routines for Computing Pressure Drops in Venturis; Software for Fault-Tolerant Matrix Multiplication; Reproducible Growth of High-Quality Cubic-SiC Layers; Nonlinear Thermoelastic Model for SMAs and SMA Hybrid Composites; Liquid-Crystal Thermosets, a New Generation of High-Performance Liquid-Crystal Polymers; Formulations for Stronger Solid Oxide Fuel-Cell Electrolytes; Simulation of Hazards and Poses for a Rocker-Bogie Rover; Autonomous Formation Flight; Expandable Purge Chambers Would Protect Cryogenic Fittings; Wavy-Planform Helicopter Blades Make Less Noise; Miniature Robotic Spacecraft for Inspecting Other Spacecraft; Miniature Ring-Shaped Peristaltic Pump; Compact Plasma Accelerator; Improved Electrohydraulic Linear Actuators; A Software Architecture for Semiautonomous Robot Control; Fabrication of Channels for Nanobiotechnological Devices; Improved Thin, Flexible Heat Pipes; Miniature Radioisotope Thermoelectric Power Cubes; Permanent Sequestration of Emitted Gases in the Form of Clathrate Hydrates; Electrochemical, H2O2-Boosted Catalytic Oxidation System; Electrokinetic In Situ Treatment of Metal-Contaminated Soil; Pumping Liquid Oxygen by Use of Pulsed Magnetic Fields; Magnetocaloric Pumping of Liquid Oxygen; Tailoring Ion-Thruster Grid Apertures for Greater Efficiency; and Lidar for Guidance of a Spacecraft or Exploratory Robot.

Two New Aircraft Traffic Surveillance Symbology Concepts: Range Filter and Inboard Field-of-View Symbology

NASA Technical Reports Server (NTRS)

Wong, Douglas T.; Kramer, Lynda J.; Norman, R. Michael

2001-01-01

The objective of this preliminary experiment was to investigate two head-up surveillance symbology (HUSS) display issues. The first issue was concerned with the benefits of adding a range filter to the current HUSS concept. A range filter limits the amount of traffic symbols displayed head-up by setting a range boundary (e.g., 7-nmi) around the ownship. The second issue was concerned with the need to incorporate HUSS in the inboard field-of-view (IFOV) display of the eXternal Visibility System (XVS) concept. The hypothesis tested was that adding a range filter to the XVS display and HUSS to the IFOV display would enhance the pilot's effectiveness in traffic surveillance tasks. Using a high-resolution graphics flight simulator, each of three pilots flew departure and arrival scenarios under visual meteorological conditions. The pilots' main tasks, while managing flight path, were to detect and assess potential airborne traffic hazards and to maintain overall situation awareness. Upon completing all the runs, each pilot completed a subjective questionnaire. Results showed that having both the HUSS on the IFOV and the range filter on each of the XVS displays enhanced the effectiveness of the XVS surveillance display concept. This configuration had the least head down time and the lowest mental workload. Combining both features gave the best target detection and, the earliest threat recognition performances, and enabled the pilots to create a better strategy for evasive action when it became necessary.

The influence of TAP1 and TAP2 gene polymorphisms on TAP function and its inhibition by viral immune evasion proteins.

PubMed

Praest, P; Luteijn, R D; Brak-Boer, I G J; Lanfermeijer, J; Hoelen, H; Ijgosse, L; Costa, A I; Gorham, R D; Lebbink, R J; Wiertz, E J H J

2018-06-04

Herpesviruses encode numerous immune evasion molecules that interfere with the immune system, particularly with certain stages in the MHC class I antigen presentation pathway. In this pathway, the transporter associated with antigen processing (TAP) is a frequent target of viral immune evasion strategies. This ER-resident transporter is composed of the proteins TAP1 and TAP2, and plays a crucial role in the loading of viral peptides onto MHC class I molecules. Several variants of TAP1 and TAP2 occur in the human population, some of which are linked to autoimmune disorders and susceptibility to infections. Here, we assessed the influence of naturally occurring TAP variants on peptide transport and MHC class I expression. In addition, we tested the inhibitory capacity of three viral immune evasion proteins, the TAP inhibitors US6 from human cytomegalovirus, ICP47 from herpes simplex virus type 1 and BNLF2a from Epstein-Barr virus, for a series of TAP1 and TAP2 variants. Our results suggest that these TAP polymorphisms have no or limited effect on peptide transport or MHC class I expression. Furthermore, our study indicates that the herpesvirus-encoded TAP inhibitors target a broad spectrum of TAP variants; inhibition of TAP is not affected by the naturally occurring polymorphisms of TAP tested in this study. Our findings suggest that the long-term coevolution of herpesviruses and their host did not result in selection of inhibitor-resistant TAP variants in the human population. Copyright © 2018. Published by Elsevier Ltd.

The p36 Isoform of Murine Cytomegalovirus m152 Protein Suffices for Mediating Innate and Adaptive Immune Evasion

PubMed Central

Fink, Annette; Renzaho, Angeliqué; Reddehase, Matthias J.; Lemmermann, Niels A. W.

2013-01-01

The MHC-class I (MHC-I)-like viral (MHC-Iv) m152 gene product of murine cytomegalovirus (mCMV) was the first immune evasion molecule described for a member of the β-subfamily of herpesviruses as a paradigm for analogous functions of human cytomegalovirus proteins. Notably, by interacting with classical MHC-I molecules and with MHC-I-like RAE1 family ligands of the activatory natural killer (NK) cell receptor NKG2D, it inhibits presentation of antigenic peptides to CD8 T cells and the NKG2D-dependent activation of NK cells, respectively, thus simultaneously interfering with adaptive and innate immune recognition of infected cells. Although the m152 gene product exists in differentially glycosylated isoforms whose individual contributions to immune evasion are unknown, it has entered the scientific literature as m152/gp40, based on the quantitatively most prominent isoform but with no functional justification. By construction of a recombinant mCMV in which all three N-glycosylation sites are mutated (N61Q, N208Q, and N241Q), we show here that N-linked glycosylation is not essential for functional interaction of the m152 immune evasion protein with either MHC-I or RAE1. These data add an important functional detail to recent structural analysis of the m152/RAE1γ complex that has revealed N-glycosylations at positions Asn61 and Asn208 of m152 distant from the m152/RAE1γ interface. PMID:24351798

Immune Evasion by Epstein-Barr Virus.

PubMed

Ressing, Maaike E; van Gent, Michiel; Gram, Anna M; Hooykaas, Marjolein J G; Piersma, Sytse J; Wiertz, Emmanuel J H J

2015-01-01

Epstein-Bar virus (EBV) is widespread within the human population with over 90% of adults being infected. In response to primary EBV infection, the host mounts an antiviral immune response comprising both innate and adaptive effector functions. Although the immune system can control EBV infection to a large extent, the virus is not cleared. Instead, EBV establishes a latent infection in B lymphocytes characterized by limited viral gene expression. For the production of new viral progeny, EBV reactivates from these latently infected cells. During the productive phase of infection, a repertoire of over 80 EBV gene products is expressed, presenting a vast number of viral antigens to the primed immune system. In particular the EBV-specific CD4+ and CD8+ memory T lymphocytes can respond within hours, potentially destroying the virus-producing cells before viral replication is completed and viral particles have been released. Preceding the adaptive immune response, potent innate immune mechanisms provide a first line of defense during primary and recurrent infections. In spite of this broad range of antiviral immune effector mechanisms, EBV persists for life and continues to replicate. Studies performed over the past decades have revealed a wide array of viral gene products interfering with both innate and adaptive immunity. These include EBV-encoded proteins as well as small noncoding RNAs with immune-evasive properties. The current review presents an overview of the evasion strategies that are employed by EBV to facilitate immune escape during latency and productive infection. These evasion mechanisms may also compromise the elimination of EBV-transformed cells, and thus contribute to malignancies associated with EBV infection.

Relationship between the loading rate of inorganic mercury to aquatic ecosystems and dissolved gaseous mercury production and evasion.

PubMed

Poulain, Alexandre J; Orihel, Diane M; Amyot, Marc; Paterson, Michael J; Hintelmann, Holger; Southworth, George R

2006-12-01

The purpose of our study was to test the hypothesis that dissolved gaseous mercury (DGM) production and evasion is directly proportional to the loading rate of inorganic mercury [Hg(II)] to aquatic ecosystems. We simulated different rates of atmospheric mercury deposition in 10-m diameter mesocosms in a boreal lake by adding multiple additions of Hg(II) enriched with a stable mercury isotope ((202)Hg). We measured DGM concentrations in surface waters and estimated evasion rates using the thin-film gas exchange model and mass transfer coefficients derived from sulfur hexafluoride (SF(6)) additions. The additions of Hg(II) stimulated DGM production, indicating that newly added Hg(II) was highly reactive. Concentrations of DGM derived from the experimental Hg(II) additions ("spike DGM") were directly proportional to the rate of Hg(II) loading to the mesocosms. Spike DGM concentrations averaged 0.15, 0.48 and 0.94 ng l(-1) in mesocosms loaded at 7.1, 14.2, and 35.5 microg Hg m(-2) yr(-1), respectively. The evasion rates of spike DGM from these mesocosms averaged 4.2, 17.2, and 22.3 ng m(-2)h(-1), respectively. The percentage of Hg(II) added to the mesocosms that was lost to the atmosphere was substantial (33-59% over 8 weeks) and was unrelated to the rate of Hg(II) loading. We conclude that changes in atmospheric mercury deposition to aquatic ecosystems will not change the relative proportion of mercury recycled to the atmosphere.

14 CFR 23.203 - Turning flight and accelerated turning stalls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... § 23.201(b), it must be possible to regain wings level flight by normal use of the flight controls, but... percent of maximum continuous power results in extreme nose-up attitudes, the test may be carried out with..., if the power-to-weight ratio at 75 percent of maximum continuous power results in nose-high attitudes...

19 CFR 122.49a - Electronic manifest requirement for passengers onboard commercial aircraft arriving in the United...

Code of Federal Regulations, 2011 CFR

2011-04-01

... operations, all-cargo flight operations, and dual flight operations involving the transport of both cargo and... capacity required for normal operation and service of the flight. In addition, the definition of “crew...) Date of birth; (iii) Gender (F = female; M = male); (iv) Citizenship; (v) Country of residence; (vi...

19 CFR 122.49a - Electronic manifest requirement for passengers onboard commercial aircraft arriving in the United...

Code of Federal Regulations, 2012 CFR

2012-04-01

... operations, all-cargo flight operations, and dual flight operations involving the transport of both cargo and... capacity required for normal operation and service of the flight. In addition, the definition of “crew...) Date of birth; (iii) Gender (F = female; M = male); (iv) Citizenship; (v) Country of residence; (vi...

19 CFR 122.49a - Electronic manifest requirement for passengers onboard commercial aircraft arriving in the United...

Code of Federal Regulations, 2010 CFR

2010-04-01

... operations, all-cargo flight operations, and dual flight operations involving the transport of both cargo and... capacity required for normal operation and service of the flight. In addition, the definition of “crew...) Date of birth; (iii) Gender (F = female; M = male); (iv) Citizenship; (v) Country of residence; (vi...

19 CFR 122.49a - Electronic manifest requirement for passengers onboard commercial aircraft arriving in the United...

Code of Federal Regulations, 2014 CFR

2014-04-01

... operations, all-cargo flight operations, and dual flight operations involving the transport of both cargo and... capacity required for normal operation and service of the flight. In addition, the definition of “crew...) Date of birth; (iii) Gender (F = female; M = male); (iv) Citizenship; (v) Country of residence; (vi...

19 CFR 122.49a - Electronic manifest requirement for passengers onboard commercial aircraft arriving in the United...

Code of Federal Regulations, 2013 CFR

2013-04-01

... operations, all-cargo flight operations, and dual flight operations involving the transport of both cargo and... capacity required for normal operation and service of the flight. In addition, the definition of “crew...) Date of birth; (iii) Gender (F = female; M = male); (iv) Citizenship; (v) Country of residence; (vi...

77 FR 69573 - Special Conditions: Embraer S.A., Model EMB-550 Airplane; Electronic Flight Control System...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-20

... airplane will have a novel or unusual design feature(s) associated with an electronic flight control system... empennage and control surfaces. The Model EMB-550 airplane is designed for 8 passengers, with a maximum of... flight control design feature within the normal operational envelope in which sidestick deflection in the...

77 FR 69569 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: Pitch and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-20

... flight characteristics associated with fixed attitude limits. Embraer S.A. will implement pitch and roll attitude protection functions through the normal modes of the electronic flight control system that will... pitch attitudes necessary for emergency maneuvering or roll angles up to 66 degrees with flaps up, or 60...

Xenopus-FV3 host-pathogen interactions and immune evasion.

PubMed

Jacques, Robert; Edholm, Eva-Stina; Jazz, Sanchez; Odalys, Torres-Luquis; Francisco, De Jesús Andino

2017-11-01

We first review fundamental insights into anti-ranavirus immunity learned with the Xenopus laevis/ranavirus FV3 model that are generally applicable to ectothermic vertebrates. We then further investigate FV3 genes involved in immune evasion. Focusing on FV3 knockout (KO) mutants defective for a putative viral caspase activation and recruitment domain-containing (CARD)-like protein (Δ64R-FV3), a β-hydroxysteroid dehydrogenase homolog (Δ52L-FV3), and an immediate-early18kDa protein (FV3-Δ18K), we assessed the involvement of these viral genes in replication, dissemination and interaction with peritoneal macrophages in tadpole and adult frogs. Our results substantiate the role of 64R and 52L as critical immune evasion genes, promoting persistence and dissemination in the host by counteracting type III IFN in tadpoles and type I IFN in adult frogs. Comparably, the substantial accumulation of genome copy numbers and exacerbation of type I and III IFN gene expression responses but deficient release of infectious virus suggests that 18K is a viral regulatory gene. Copyright © 2017 Elsevier Inc. All rights reserved.

AGATE: Adversarial Game Analysis for Tactical Evaluation

NASA Technical Reports Server (NTRS)

Huntsberger, Terrance L.

2013-01-01

AGATE generates a set of ranked strategies that enables an autonomous vehicle to track/trail another vehicle that is trying to break the contact using evasive tactics. The software is efficient (can be run on a laptop), scales well with environmental complexity, and is suitable for use onboard an autonomous vehicle. The software will run in near-real-time (2 Hz) on most commercial laptops. Existing software is usually run offline in a planning mode, and is not used to control an unmanned vehicle actively. JPL has developed a system for AGATE that uses adversarial game theory (AGT) methods (in particular, leader-follower and pursuit-evasion) to enable an autonomous vehicle (AV) to maintain tracking/ trailing operations on a target that is employing evasive tactics. The AV trailing, tracking, and reacquisition operations are characterized by imperfect information, and are an example of a non-zero sum game (a positive payoff for the AV is not necessarily an equal loss for the target being tracked and, potentially, additional adversarial boats). Previously, JPL successfully applied the Nash equilibrium method for onboard control of an autonomous ground vehicle (AGV) travelling over hazardous terrain.

Postural stability and vehicle kinematics during an evasive lane change manoeuvre: a driver training study.

PubMed

Petersen, Andrew; Barrett, Rod

2009-05-01

The purpose of this study was to investigate the effect of a 2-day driver-training course that emphasised postural stability maintenance during critical driving situations on postural stability and vehicle kinematics during an evasive lane change manoeuvre. Following training, the trainee group experienced enhanced postural stability during specific phases of the task. In terms of vehicle kinematics, the main adaptation to training was that trained drivers reduced the extent to which they experienced vehicle decelerations during rapid turning compared to controls. Such a strategy may confer a safety benefit due to the increased risks associated with simultaneous braking while turning during an evasive manoeuvre. The newly learned strategy was consistent with the strategy used by a group of highly skilled drivers (driving instructors). Taken together, the results of the study suggest postural stability may be a useful variable to consider in relation to the skill-based component of hierarchical driver training programmes. The findings of this study provide some preliminary evidence to suggest that postural stability may be an important consideration when instructing individuals on how to safely negotiate obstacles during driving.

Biotelemetry and computer analysis of sleep processes on earth and in space.

NASA Technical Reports Server (NTRS)

Adey, W. R.

1972-01-01

Developments in biomedical engineering now permit study of states of sleep, wakefulness, and focused attention in man exposed to rigorous environments, including aerospace flight. These new sensing devices, data acquisition systems, and computational methods have also been extensively applied to clinical problems of disordered sleep. A 'library' of EEG data has been prepared for sleep in normal man, and characterized for its group features by computational analysis. Sleep in an astronaut in space flight has been examined for the first and second 'nights' of space flight. Normal 90-min cycles were detected during the second night. Sleep patterns in quadriplegic patients deprived of all sensory inputs below the neck have indicated major deviations.

Addressing the psychosocial wellbeing of teenage children of cancer patients and survivors.

PubMed

Annunziata, Maria Antonietta; Muzzatti, Barbara; Surbone, Antonella

2016-02-01

Thomas is 13 years old. His parents report a sharp decline in his school grades caused, according to his teachers' opinions, by listlessness and lack of concentration. The parents of Julia, 16 years old, describe her as restless, evasive, isolated, and withdrawn from others and from her usual activities. Linda, 18 years old, is described by her parents as indecisive, uncertain, and almost lethargic. Normally resolute and a high academic achiever, she appears locked in herself, unable to make choices. We first learned about them through the accounts of their concerned parents. Claire, 19 years old, lost weight and exercised hard enough to induce amenorrhea after her young mother underwent treatment for breast cancer, including antihormonal treatment. These four teenagers have in common a parent diagnosed with cancer, undergoing or having just completed treatment.

The flights before the flight - An overview of shuttle astronaut training

NASA Technical Reports Server (NTRS)

Sims, John T.; Sterling, Michael R.

1989-01-01

Space shuttle astronaut training is centered at NASA's Johnson Space Center in Houston, Texas. Each astronaut receives many different types of training from many sources. This training includes simulator training in the Shuttle Mission Simulator, in-flight simulator training in the Shuttle Training Aircraft, Extravehicular Activity training in the Weightless Environment Training Facility and a variety of lectures and briefings. Once the training program is completed each shuttle flight crew is well-prepared to perform the normal operations required for their flight and deal with any shuttle system malfunctions that might occur.

Simulating effectiveness of helicopter evasive manoeuvres to RPG attack

NASA Astrophysics Data System (ADS)

Anderson, D.; Thomson, D. G.

2010-04-01

The survivability of helicopters under attack by ground troops using rocket propelled grenades has been amply illustrated over the past decade. Given that an RPG is unguided and it is infeasible to cover helicopters in thick armour, existing optical countermeasures are ineffective - the solution is to compute an evasive manoeuvre. In this paper, an RPG/helicopter engagement model is presented. Manoeuvre profiles are defined in the missile approach warning sensor camera image plane using a local maximum acceleration vector. Required control inputs are then computed using inverse simulation techniques. Assessments of platform survivability to several engagement scenarios are presented.

The quantum limit for gravitational-wave detectors and methods of circumventing it

NASA Technical Reports Server (NTRS)

Thorne, K. S.; Caves, C. M.; Sandberg, V. D.; Zimmermann, M.; Drever, R. W. P.

1979-01-01

The Heisenberg uncertainty principle prevents the monitoring of the complex amplitude of a mechanical oscillator more accurately than a certain limit value. This 'quantum limit' is a serious obstacle to the achievement of a 10 to the -21st gravitational-wave detection sensitivity. This paper examines the principles of the back-action evasion technique and finds that this technique may be able to overcome the problem of the quantum limit. Back-action evasion does not solve, however, other problems of detection, such as weak coupling, large amplifier noise, and large Nyquist noise.

Effects of short-term weightlessness on inner ear carbonic anhydrase reactivity in fish - a parabolic aircraft flight study

NASA Astrophysics Data System (ADS)

Anken, Ralf; Hilbig, Reinhard; Weigele, Jochen; Anken, Ralf

We have shown earlier that some fish of a given batch reveal motion sickness (a kinetosis) at the transition from increased gravity (hypergravity, hg; centrifuge) to 1g earth gravity. Total macular carbonic anhydrase (CA)-reactivity as well as the difference in reactivities between left and right maculae (asymmetry) were significantly lower in normally swimming hg-animals as compared to the kinetotically behaving hg-fish. This result clearly indicated the existence of a regulatory mechanism, which adjusts otolithic calcium carbonate incorporation via CA- reactivity towards the gravity vector. Thus, we were prompted to investigate, whether fish swimming kinetotically under weightlessness also would reveal an asymmetric CA-reactivity. Therefore, larval cichlid fish (Oreochromis mossambicus) were subjected to parabolic aircraft flights. During the flights, the animals were videorecorded. Subsequently, fish were separated according to their respective swimming behaviour into normally and abnormally (kinetotic) moving individuals (the latter performed spinning movements, i.e., turns around their longitudinal axis). Finally, CA was localized histochemically and densitometrically determined in inner ear maculae. It was found that the total macular CA-reactivity did not differ between ground controls and kinetotically or normally swimming experimental fish. Asymmetry of CA- reactivity, however, was considerably higher in experimental animals as compared to the ground controls. No difference in asymmetry of CA-reactivity was obtained when comparing kinetotic with normally behaving individuals. These results indicate that parabolic flights do not affect CA-reactivity in general, possibly due to the relatively quickly alternating G-levels (g-profile of single parabola: 1g/1.8g/0.04g/1.8g/1g, performed in 70 seconds) in up to 30 parabolas per flight day. The high asymmetry of CA-reactivity in the experimental animals - irrespective of their behaviour - probably indicates an adaptation process, which has presumably been successful in the normally swimming samples. Acknowledgement: This work was financially supported by the German Aerospace Center (DLR) (FKZ: 50 WB 0527).

How the bat got its buzz

PubMed Central

Ratcliffe, John M.; Elemans, Coen P. H.; Jakobsen, Lasse; Surlykke, Annemarie

2013-01-01

Since the discovery of echolocation in bats, the final phase of an attack on a flying insect, the ‘terminal buzz’, has proved enigmatic. During the buzz, bats increase information update rates by producing vocalizations up to 220 times s−1. The buzz's ubiquity in hawking and trawling bats implies its importance for hunting success. Superfast muscles, previously unknown in mammals, are responsible for the extreme vocalization rate. Some bats produce a second phase—buzz II—defined by a large drop in the fundamental frequency (F0) of their calls. By doing so, bats broaden their acoustic field of view and should thereby reduce the likelihood of insect escape. We make the case that the buzz was a critical adaptation for capturing night-flying insects, and suggest that the drop in F0 during buzz II requires novel, unidentified laryngeal mechanisms in order to counteract increasing muscle tension. Furthermore, we propose that buzz II represents a countermeasure against the evasive flight of eared prey in the evolutionary arms-race that saw the independent evolution of bat-detecting ears in various groups of night-flying insects. PMID:23302868

Optimal helicopter trajectory planning for terrain following flight

NASA Technical Reports Server (NTRS)

Menon, P. K. A.

1990-01-01

Helicopters operating in high threat areas have to fly close to the earth surface to minimize the risk of being detected by the adversaries. Techniques are presented for low altitude helicopter trajectory planning. These methods are based on optimal control theory and appear to be implementable onboard in realtime. Second order necessary conditions are obtained to provide a criterion for finding the optimal trajectory when more than one extremal passes through a given point. A second trajectory planning method incorporating a quadratic performance index is also discussed. Trajectory planning problem is formulated as a differential game. The objective is to synthesize optimal trajectories in the presence of an actively maneuvering adversary. Numerical methods for obtaining solutions to these problems are outlined. As an alternative to numerical method, feedback linearizing transformations are combined with the linear quadratic game results to synthesize explicit nonlinear feedback strategies for helicopter pursuit-evasion. Some of the trajectories generated from this research are evaluated on a six-degree-of-freedom helicopter simulation incorporating an advanced autopilot. The optimal trajectory planning methods presented are also useful for autonomous land vehicle guidance.

Several immune escape patterns in non-Hodgkin's lymphomas

PubMed Central

Laurent, Camille; Charmpi, Konstantina; Gravelle, Pauline; Tosolini, Marie; Franchet, Camille; Ysebaert, Loïc; Brousset, Pierre; Bidaut, Alexandre; Ycart, Bernard; Fournié, Jean-Jacques

2015-01-01

Follicular Lymphomas (FL) and diffuse large B cell lymphomas (DLBCL) must evolve some immune escape strategy to develop from lymphoid organs, but their immune evasion pathways remain poorly characterized. We investigated this issue by transcriptome data mining and immunohistochemistry (IHC) of FL and DLBCL lymphoma biopsies. A set of genes involved in cancer immune-evasion pathways (Immune Escape Gene Set, IEGS) was defined and the distribution of the expression levels of these genes was compared in FL, DLBCL and normal B cell transcriptomes downloaded from the GEO database. The whole IEGS was significantly upregulated in all the lymphoma samples but not in B cells or other control tissues, as shown by the overexpression of the PD-1, PD-L1, PD-L2 and LAG3 genes. Tissue microarray immunostainings for PD-1, PD-L1, PD-L2 and LAG3 proteins on additional biopsies from 27 FL and 27 DLBCL patients confirmed the expression of these proteins. The immune infiltrates were more abundant in FL than DLBCL samples, and the microenvironment of FL comprised higher rates of PD-1+ lymphocytes. Further, DLBCL tumor cells comprised a higher proportion of PD-1+, PD-L1+, PD-L2+ and LAG3+ lymphoma cells than the FL tumor cells, confirming that DLBCL mount immune escape strategies distinct from FL. In addition, some cases of DLBCL had tumor cells co-expressing both PD-1, PD-L1 and PD-L2. Among the DLBCLs, the activated B cell (ABC) subtype comprised more PD-L1+ and PD-L2+ lymphoma cells than the GC subtype. Thus, we infer that FL and DLBCL evolved several pathways of immune escape. PMID:26405585

Galectin-1 influences trophoblast immune evasion and emerges as a predictive factor for the outcome of pregnancy.

PubMed

Tirado-González, Irene; Freitag, Nancy; Barrientos, Gabriela; Shaikly, Valerie; Nagaeva, Olga; Strand, Magnus; Kjellberg, Lennart; Klapp, Burghard F; Mincheva-Nilsson, Lucia; Cohen, Marie; Blois, Sandra M

2013-01-01

Galectin-1 (gal-1) is expressed at the feto-maternal interface and plays a role in regulating the maternal immune response against placental alloantigens, contributing to pregnancy maintenance. Both decidua and placenta contribute to gal-1 expression and may be important for the maternal immune regulation. The expression of gal-1 within the placenta is considered relevant to cell-adhesion and invasion of trophoblasts, but the role of gal-1 in the immune evasion machinery exhibited by trophoblast cells remains to be elucidated. In this study, we analyzed gal-1 expression in preimplantation human embryos and first-trimester decidua-placenta specimens and serum gal-1 levels to investigate the physiological role played by this lectin during pregnancy. The effect on human leukocyte antigen G (HLA-G) expression in response to stimulation or silencing of gal-1 was also determined in the human invasive, proliferative extravillous cytotrophoblast 65 (HIPEC65) cell line. Compared with normal pregnant women, circulating gal-1 levels were significantly decreased in patients who subsequently suffered a miscarriage. Human embryos undergoing preimplantation development expressed gal-1 on the trophectoderm and inner cell mass. Furthermore, our in vitro experiments showed that exogenous gal-1 positively regulated the membrane-bound HLA-G isoforms (HLA-G1 and G2) in HIPEC65 cells, whereas endogenous gal-1 also induced expression of the soluble isoforms (HLA-G5 and -G6). Our results suggest that gal-1 plays a key role in pregnancy maternal immune regulation by modulating HLA-G expression on trophoblast cells. Circulating gal-1 levels could serve as a predictive factor for pregnancy success in early human gestation.

Energetics and evasion dynamics of large predators and prey: pumas vs. hounds.

PubMed

Bryce, Caleb M; Wilmers, Christopher C; Williams, Terrie M

2017-01-01

Quantification of fine-scale movement, performance, and energetics of hunting by large carnivores is critical for understanding the physiological underpinnings of trophic interactions. This is particularly challenging for wide-ranging terrestrial canid and felid predators, which can each affect ecosystem structure through distinct hunting modes. To compare free-ranging pursuit and escape performance from group-hunting and solitary predators in unprecedented detail, we calibrated and deployed accelerometer-GPS collars during predator-prey chase sequences using packs of hound dogs ( Canis lupus familiaris , 26 kg, n  = 4-5 per chase) pursuing simultaneously instrumented solitary pumas ( Puma concolor , 60 kg, n  = 2). We then reconstructed chase paths, speed and turning angle profiles, and energy demands for hounds and pumas to examine performance and physiological constraints associated with cursorial and cryptic hunting modes, respectively. Interaction dynamics revealed how pumas successfully utilized terrain (e.g., fleeing up steep, wooded hillsides) as well as evasive maneuvers (e.g., jumping into trees, running in figure-8 patterns) to increase their escape distance from the overall faster hounds (avg. 2.3× faster). These adaptive strategies were essential to evasion in light of the mean 1.6× higher mass-specific energetic costs of the chase for pumas compared to hounds (mean: 0.76 vs. 1.29 kJ kg -1  min -1 , respectively). On an instantaneous basis, escapes were more costly for pumas, requiring exercise at ≥90% of predicted [Formula: see text] and consuming as much energy per minute as approximately 5 min of active hunting. Our results demonstrate the marked investment of energy for evasion by a large, solitary carnivore and the advantage of dynamic maneuvers to postpone being overtaken by group-hunting canids.

Sequence variations and protein expression levels of the two immune evasion proteins Gpm1 and Pra1 influence virulence of clinical Candida albicans isolates.

PubMed

Luo, Shanshan; Hipler, Uta-Christina; Münzberg, Christin; Skerka, Christine; Zipfel, Peter F

2015-01-01

Candida albicans, the important human fungal pathogen uses multiple evasion strategies to control, modulate and inhibit host complement and innate immune attack. Clinical C. albicans strains vary in pathogenicity and in serum resistance, in this work we analyzed sequence polymorphisms and variations in the expression levels of two central fungal complement evasion proteins, Gpm1 (phosphoglycerate mutase 1) and Pra1 (pH-regulated antigen 1) in thirteen clinical C. albicans isolates. Four nucleotide (nt) exchanges, all representing synonymous exchanges, were identified within the 747-nt long GPM1 gene. For the 900-nt long PRA1 gene, sixteen nucleotide exchanges were identified, which represented synonymous, as well as non-synonymous exchanges. All thirteen clinical isolates had a homozygous exchange (A to G) at position 73 of the PRA1 gene. Surface levels of Gpm1 varied by 8.2, and Pra1 levels by 3.3 fold in thirteen tested isolates and these differences influenced fungal immune fitness. The high Gpm1/Pra1 expressing candida strains bound the three human immune regulators more efficiently, than the low expression strains. The difference was 44% for Factor H binding, 51% for C4BP binding and 23% for plasminogen binding. This higher Gpm1/Pra1 expressing strains result in enhanced survival upon challenge with complement active, Factor H depleted human serum (difference 40%). In addition adhesion to and infection of human endothelial cells was increased (difference 60%), and C3b surface deposition was less effective (difference 27%). Thus, variable expression levels of central immune evasion protein influences immune fitness of the human fungal pathogen C. albicans and thus contribute to fungal virulence.

Staphylococcus aureus SdrE captures complement factor H's C-terminus via a novel ‘close, dock, lock and latch' mechanism for complement evasion

PubMed Central

Zhang, Yingjie; Wu, Minhao; Hang, Tianrong; Wang, Chengliang; Yang, Ye; Pan, Weimin; Zang, Jianye

2017-01-01

Complement factor H (CFH) is a soluble complement regulatory protein essential for the down-regulation of the alternative pathway on interaction with specific markers on the host cell surface. It recognizes the complement component 3b (C3b) and 3d (C3d) fragments in addition to self cell markers (i.e. glycosaminoglycans, sialic acid) to distinguish host cells that deserve protection from pathogens that should be eliminated. The Staphylococcus aureus surface protein serine–aspartate repeat protein E (SdrE) was previously reported to bind human CFH as an immune-evasion tactic. However, the molecular mechanism underlying SdrE–CFH-mediated immune evasion remains unknown. In the present study, we identified a novel region at CFH's C-terminus (CFH1206–1226), which binds SdrE N2 and N3 domains (SdrEN2N3) with high affinity, and determined the crystal structures of apo-SdrEN2N3 and the SdrEN2N3–CFH1206–1226 complex. Comparison of the structure of the CFH–SdrE complex with other CFH structures reveals that CFH's C-terminal tail flips from the main body to insert into the ligand-binding groove of SdrE. In addition, SdrEN2N3 adopts a ‘close’ state in the absence of CFH, which undergoes a large conformational change on CFH binding, suggesting a novel ‘close, dock, lock and latch' (CDLL) mechanism for SdrE to recognize its ligand. Our findings imply that SdrE functions as a ‘clamp' to capture CFH's C-terminal tail via a unique CDLL mechanism and sequesters CFH on the surface of S. aureus for complement evasion. PMID:28258151

Tumor immune evasion arises through loss of TNF sensitivity.

PubMed

Kearney, Conor J; Vervoort, Stephin J; Hogg, Simon J; Ramsbottom, Kelly M; Freeman, Andrew J; Lalaoui, Najoua; Pijpers, Lizzy; Michie, Jessica; Brown, Kristin K; Knight, Deborah A; Sutton, Vivien; Beavis, Paul A; Voskoboinik, Ilia; Darcy, Phil K; Silke, John; Trapani, Joseph A; Johnstone, Ricky W; Oliaro, Jane

2018-05-18

Immunotherapy has revolutionized outcomes for cancer patients, but the mechanisms of resistance remain poorly defined. We used a series of whole-genome clustered regularly interspaced short palindromic repeat (CRISPR)-based screens performed in vitro and in vivo to identify mechanisms of tumor immune evasion from cytotoxic lymphocytes [CD8 + T cells and natural killer (NK) cells]. Deletion of key genes within the tumor necrosis factor (TNF) signaling, interferon-γ (IFN-γ) signaling, and antigen presentation pathways provided protection of tumor cells from CD8 + T cell-mediated killing and blunted antitumor immune responses in vivo. Deletion of a number of genes in the TNF pathway also emerged as the key mechanism of immune evasion from primary NK cells. Our screens also identified that the metabolic protein 2-aminoethanethiol dioxygenase (Ado) modulates sensitivity to TNF-mediated killing by cytotoxic lymphocytes and is required for optimal control of tumors in vivo. Remarkably, we found that tumors delete the same genes when exposed to perforin-deficient CD8 + T cells, demonstrating that the dominant immune evasion strategy used by tumor cells is acquired resistance to T cell-derived cytokine-mediated antitumor effects. We demonstrate that TNF-mediated bystander killing is a potent T cell effector mechanism capable of killing antigen-negative tumor cells. In addition to highlighting the importance of TNF in CD8 + T cell- and NK cell-mediated killing of tumor cells, our study also provides a comprehensive picture of the roles of the TNF, IFN, and antigen presentation pathways in immune-mediated tumor surveillance. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Flaviviridae virus nonstructural proteins 5 and 5A mediate viral immune evasion and are promising targets in drug development.

PubMed

Chen, Shun; Yang, Chao; Zhang, Wei; Mahalingam, Suresh; Wang, Mingshu; Cheng, Anchun

2018-05-06

Infections with viruses in the Flaviviridae family have a vast global and economic impact because of the high morbidity and mortality. The pathogenesis of Flaviviridae infections is very complex and not fully understood because these viruses can inhibit multiple immune pathways including the complement system, NK cells, and IFN induction and signalling pathways. The non-structural (NS) 5 and 5A proteins of Flaviviridae viruses are highly conserved and play an important role in resisting host immunity through various evasion mechanisms. This review summarizes the strategies used by the NS5 and 5A proteins of Flaviviridae viruses for evading the innate immune response by inhibiting pattern recognition receptor (PRR) signalling pathways (TLR/MyD88, IRF7), suppressing interferon (IFN) signalling pathways (IFN-γRs, STAT1, STAT2), and impairing the function of IFN-stimulated genes (ISGs) (e.g. protein kinase R [PKR], oligoadenylate synthase [OAS]). All of these immune evasion mechanisms depend on the interaction of NS5 or NS5A with cellular proteins, such as MyD88 and IRF7, IFN-αRs, IFN-γRs, STAT1, STAT2, PKR and OAS. NS5 is the most attractive target for the discovery of broad spectrum compounds against Flaviviridae virus infection. The methyltransferase (MTase) and RNA-dependent RNA polymerase (RdRp) activities of NS5 are the main therapeutic targets for antiviral drugs against Flaviviridae virus infection. Based on our site mapping, the sites involved in immune evasion provide some potential and promising targets for further novel antiviral therapeutics. Copyright © 2018 Elsevier Inc. All rights reserved.

Staphylococcus aureus SdrE captures complement factor H's C-terminus via a novel 'close, dock, lock and latch' mechanism for complement evasion.

PubMed

Zhang, Yingjie; Wu, Minhao; Hang, Tianrong; Wang, Chengliang; Yang, Ye; Pan, Weimin; Zang, Jianye; Zhang, Min; Zhang, Xuan

2017-05-04

Complement factor H (CFH) is a soluble complement regulatory protein essential for the down-regulation of the alternative pathway on interaction with specific markers on the host cell surface. It recognizes the complement component 3b (C3b) and 3d (C3d) fragments in addition to self cell markers (i.e. glycosaminoglycans, sialic acid) to distinguish host cells that deserve protection from pathogens that should be eliminated. The Staphylococcus aureus surface protein serine-aspartate repeat protein E (SdrE) was previously reported to bind human CFH as an immune-evasion tactic. However, the molecular mechanism underlying SdrE-CFH-mediated immune evasion remains unknown. In the present study, we identified a novel region at CFH's C-terminus (CFH 1206-1226 ), which binds SdrE N2 and N3 domains (SdrE N2N3 ) with high affinity, and determined the crystal structures of apo-SdrE N2N3 and the SdrE N2N3 -CFH 1206-1226 complex. Comparison of the structure of the CFH-SdrE complex with other CFH structures reveals that CFH's C-terminal tail flips from the main body to insert into the ligand-binding groove of SdrE. In addition, SdrE N2N3 adopts a 'close' state in the absence of CFH, which undergoes a large conformational change on CFH binding, suggesting a novel 'close, dock, lock and latch' (CDLL) mechanism for SdrE to recognize its ligand. Our findings imply that SdrE functions as a 'clamp' to capture CFH's C-terminal tail via a unique CDLL mechanism and sequesters CFH on the surface of S. aureus for complement evasion. © 2017 The Author(s).

Trichinella spiralis Calreticulin Binds Human Complement C1q As an Immune Evasion Strategy.

PubMed

Zhao, Limei; Shao, Shuai; Chen, Yi; Sun, Ximeng; Sun, Ran; Huang, Jingjing; Zhan, Bin; Zhu, Xinping

2017-01-01

As a multicellular parasitic nematode, Trichinella spiralis regulates host immune responses by producing a variety of immunomodulatory molecules to escape from host immune attack, but the mechanisms underlying the immune evasion are not well understood. Here, we identified that T. spiralis calreticulin ( Ts -CRT), a Ca 2+ -binding protein, facilitated T. spiralis immune evasion by interacting with the first component of human classical complement pathway, C1q. In the present study, Ts -CRT was found to be expressed on the surface of different developmental stages of T. spiralis as well as in the secreted products of adult and muscle larval worms. Functional analysis identified that Ts -CRT was able to bind to human C1q, resulting in the inhibition of C1q-initiated complement classical activation pathway reflected by reduced C4/C3 generation and C1q-dependent lysis of antibody-sensitized sheep erythrocytes. Moreover, recombinant Ts -CRT (r Ts -CRT) binding to C1q suppressed C1q-induced THP-1-derived macrophages chemotaxis and reduced monocyte-macrophages release of reactive oxygen intermediates (ROIs). Blocking Ts -CRT on the surface of newborn larvae (NBL) of T. spiralis with anti- Ts -CRT antibody increased the C1q-mediated adherence of monocyte-macrophages to larvae and impaired larval infectivity. All of these results suggest that T. spiralis -expressed Ts -CRT plays crucial roles in T. spiralis immune evasion and survival in host mostly by directly binding to host complement C1q, which not only reduces C1q-mediated activation of classical complement pathway but also inhibits the C1q-induced non-complement activation of macrophages.

Trichinella spiralis Calreticulin Binds Human Complement C1q As an Immune Evasion Strategy

PubMed Central

Zhao, Limei; Shao, Shuai; Chen, Yi; Sun, Ximeng; Sun, Ran; Huang, Jingjing; Zhan, Bin; Zhu, Xinping

2017-01-01

As a multicellular parasitic nematode, Trichinella spiralis regulates host immune responses by producing a variety of immunomodulatory molecules to escape from host immune attack, but the mechanisms underlying the immune evasion are not well understood. Here, we identified that T. spiralis calreticulin (Ts-CRT), a Ca2+-binding protein, facilitated T. spiralis immune evasion by interacting with the first component of human classical complement pathway, C1q. In the present study, Ts-CRT was found to be expressed on the surface of different developmental stages of T. spiralis as well as in the secreted products of adult and muscle larval worms. Functional analysis identified that Ts-CRT was able to bind to human C1q, resulting in the inhibition of C1q-initiated complement classical activation pathway reflected by reduced C4/C3 generation and C1q-dependent lysis of antibody-sensitized sheep erythrocytes. Moreover, recombinant Ts-CRT (rTs-CRT) binding to C1q suppressed C1q-induced THP-1-derived macrophages chemotaxis and reduced monocyte–macrophages release of reactive oxygen intermediates (ROIs). Blocking Ts-CRT on the surface of newborn larvae (NBL) of T. spiralis with anti-Ts-CRT antibody increased the C1q-mediated adherence of monocyte–macrophages to larvae and impaired larval infectivity. All of these results suggest that T. spiralis-expressed Ts-CRT plays crucial roles in T. spiralis immune evasion and survival in host mostly by directly binding to host complement C1q, which not only reduces C1q-mediated activation of classical complement pathway but also inhibits the C1q-induced non-complement activation of macrophages. PMID:28620388

New technique for quantification of elemental hg in mine wastes and its implications for mercury evasion into the atmosphere

USGS Publications Warehouse

Jew, A.D.; Kim, C.S.; Rytuba, J.J.; Gustin, M.S.; Brown, Gordon E.

2011-01-01

Mercury in the environment is of prime concern to both ecosystem and human health. Determination of the molecular-level speciation of Hg in soils and mine wastes is important for understanding its sequestration, mobility, and availability for methylation. Extended X-ray absorption fine structure (EXAFS) spectroscopy carried out under ambient P-T conditions has been used in a number of past studies to determine Hg speciation in complex mine wastes and associated soils. However, this approach cannot detect elemental (liquid) mercury in Hg-polluted soils and sediments due to the significant structural disorder of liquid Hg at ambient-temperature. A new sample preparation protocol involving slow cooling through the crystallization temperature of Hg(0) (234 K) results in its transformation to crystalline ??-Hg(0). The presence and proportion of Hg(0), relative to other crystalline Hg-bearing phases, in samples prepared in this way can be quantified by low-temperature (77 K) EXAFS spectroscopy. Using this approach, we have determined the relative concentrations of liquid Hg(0) in Hg mine wastes from several sites in the California Coast Range and have found that they correlate well with measured fluxes of gaseous Hg released during light and dark exposure of the same samples, with higher evasion ratios from samples containing higher concentrations of liquid Hg(0). Two different linear relationships are observed in plots of the ratio of Hg emission under light and dark conditions vs % Hg(0), corresponding to silica-carbonate- and hot springs-type Hg deposits, with the hot springs-type samples exhibiting higher evasion fluxes than silica-carbonate type samples at similar Hg(0) concentrations. Our findings help explain significant differences in Hg evasion data for different mine sites in the California Coast Range. ?? 2011 American Chemical Society.

Studies of planning behavior of aircraft pilots in normal, abnormal, and emergency situations

NASA Technical Reports Server (NTRS)

Johannsen, G.; Rouse, W. B.; Hillmann, K.

1981-01-01

A methodology for the study of human planning behavior in complex dynamic systems is presented and applied to the study of aircraft pilot behavior in normal, abnormal and emergency situations. The method measures the depth of planning, that is the level of detail employed with respect to a specific task, according to responses to a verbal questionnaire, and compares planning depth with variables relating to time, task criticality and the probability of increased task difficulty. In two series of experiments, depth of planning was measured on a five- or ten-point scale during various phases of flight in a HFB-320 simulator under normal flight conditions, abnormal scenarios involving temporary runway closure due to snow removal or temporary CAT-III conditions due to a dense fog, and emergency scenarios involving engine shut-down or hydraulic pressure loss. Results reveal a dichotomy between event-driven and time-driven planning, different effects of automation in abnormal and emergency scenarios and a low correlation between depth of planning and workload or flight performance.

14 CFR 27.321 - General.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false General. 27.321 Section 27.321 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.321 General. (a) The flight...

A new method for flight test determination of propulsive efficiency and drag coefficient

NASA Technical Reports Server (NTRS)

Bull, G.; Bridges, P. D.

1983-01-01

A flight test method is described from which propulsive efficiency as well as parasite and induced drag coefficients can be directly determined using relatively simple instrumentation and analysis techniques. The method uses information contained in the transient response in airspeed for a small power change in level flight in addition to the usual measurement of power required for level flight. Measurements of pitch angle and longitudinal and normal acceleration are eliminated. The theoretical basis for the method, the analytical techniques used, and the results of application of the method to flight test data are presented.

Total energy based flight control system

NASA Technical Reports Server (NTRS)

Lambregts, Antonius A. (Inventor)

1985-01-01

An integrated aircraft longitudinal flight control system uses a generalized thrust and elevator command computation (38), which accepts flight path angle, longitudinal acceleration command signals, along with associated feedback signals, to form energy rate error (20) and energy rate distribution error (18) signals. The engine thrust command is developed (22) as a function of the energy rate distribution error and the elevator position command is developed (26) as a function of the energy distribution error. For any vertical flight path and speed mode the outerloop errors are normalized (30, 34) to produce flight path angle and longitudinal acceleration commands. The system provides decoupled flight path and speed control for all control modes previously provided by the longitudinal autopilot, autothrottle and flight management systems.

Flight control actuation system

NASA Technical Reports Server (NTRS)

Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

2004-01-01

A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

Flight control actuation system

NASA Technical Reports Server (NTRS)

Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

2006-01-01

A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

Mechanisms of Immune Evasion in Leishmaniasis

PubMed Central

Gupta, Gaurav; Oghumu, Steve; Satoskar, Abhay R.

2013-01-01

Diseases caused by Leishmania present a worldwide problem, and current therapeutic approaches are unable to achieve a sterile cure. Leishmania is able to persist in host cells by evading or exploiting host immune mechanisms. A thorough understanding of these mechanisms could lead to better strategies for effective management of Leishmania infections. Current research has focused on parasite modification of host cell signaling pathways, entry into phagocytic cells, and modulation of cytokine and chemokine profiles that alter immune cell activation and trafficking to sites of infection. Immuno-therapeutic approaches that target these mechanisms of immune evasion by Leishmania offer promising areas for preclinical and clinical research. PMID:23415155

Filovirus pathogenesis and immune evasion: insights from Ebola virus and Marburg virus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Messaoudi, Ilhem; Amarasinghe, Gaya K.; Basler, Christopher F.

Ebola viruses and Marburg viruses, members of the filovirus family, are zoonotic pathogens that cause severe disease in people, as highlighted by the latest Ebola virus epidemic in West Africa. Filovirus disease is characterized by uncontrolled virus replication and the activation of host responses that contribute to pathogenesis. Underlying these phenomena is the potent suppression of host innate antiviral responses, particularly the type I interferon response, by viral proteins, which allows high levels of viral replication. In this Review, we describe the mechanisms used by filoviruses to block host innate immunity and discuss the links between immune evasion and filovirusmore » pathogenesis.« less

Cumulative Search-Evasion Games (CSEGs)

DTIC Science & Technology

1989-03-01

EVASI ON GAMES ( CSEGs ) . PERSONAL A UTHOR(S) Ea gl e , James N. ’ and Was hb urn , Alan R. a. TYPE OF REPO RT 113b T ME COVERED 114 DATE O F REPORT...Cumulative search - eva s ion games ( CSEGs) are t wo- pe r son ze r o- s um search- evasion games whe re p l ay proceeds t h r o ughout some speci fied pe...t he p ositions of the two players at time t’ t h e n the game ’ s p ayoff i s the sum over t from 1 to T of A( X ,Y ,t) . Additionally, all paths

Filovirus pathogenesis and immune evasion: insights from Ebola virus and Marburg virus.

PubMed

Messaoudi, Ilhem; Amarasinghe, Gaya K; Basler, Christopher F

2015-11-01

Ebola viruses and Marburg viruses, members of the filovirus family, are zoonotic pathogens that cause severe disease in people, as highlighted by the latest Ebola virus epidemic in West Africa. Filovirus disease is characterized by uncontrolled virus replication and the activation of host responses that contribute to pathogenesis. Underlying these phenomena is the potent suppression of host innate antiviral responses, particularly the type I interferon response, by viral proteins, which allows high levels of viral replication. In this Review, we describe the mechanisms used by filoviruses to block host innate immunity and discuss the links between immune evasion and filovirus pathogenesis.

[Evasion of anti-infectious immunity by Brucella - A review].

PubMed

Quan, Wurong; Yang, Yongjie

2016-05-04

Brucellosis, caused by Brucella species, is a worldwide zoonosis. As facultative intracellular pathogens, Brucella possess non-classical virulence factor, but its virulence is very powerful and can elicit chronic infections of both animals and humans. Evasion of host anti-infectious immunity is a prerequisite for chronic infections, this ability appears increasingly crucial for Brucella virulence. As successful pathogens, Brucella can escape or suppress innate immunity and modulate adaptive immunity to establish long lasting infections in host cells. In this review, we address the molecular mechanisms of Brucella to evade anti-infectious immunity. This will shed new insights on Brucella virulence and will, potentially, open new prophylactic avenues.

Viral Evasion of Natural Killer Cell Activation

PubMed Central

Ma, Yi; Li, Xiaojuan; Kuang, Ersheng

2016-01-01

Natural killer (NK) cells play a key role in antiviral innate defenses because of their abilities to kill infected cells and secrete regulatory cytokines. Additionally, NK cells exhibit adaptive memory-like antigen-specific responses, which represent a novel antiviral NK cell defense mechanism. Viruses have evolved various strategies to evade the recognition and destruction by NK cells through the downregulation of the NK cell activating receptors. Here, we review the recent findings on viral evasion of NK cells via the impairment of NK cell-activating receptors and ligands, which provide new insights on the relationship between NK cells and viral actions during persistent viral infections. PMID:27077876

Mechanism of immune evasion in breast cancer

PubMed Central

Wang, Mozhi; Zhang, Changwang; Song, Yongxi; Wang, Zhenning; Wang, Yaojia; Luo, Fang; Xu, Yujie; Zhao, Yi; Wu, Zhonghua; Xu, Yingying

2017-01-01

Breast cancer (BC) is the most common malignant tumor among women, with high morbidity and mortality. Its onset, development, metastasis, and prognosis vary among individuals due to the interactions between tumors and host immunity. Many diverse mechanisms have been associated with BC, with immune evasion being the most widely studied to date. Tumor cells can escape from the body’s immune response, which targets abnormal components and foreign bodies, using different approaches including modification of surface antigens and modulation of the surrounding environment. In this review, we summarize the mechanisms and factors that impact the immunoediting process and analyze their functions in detail. PMID:28352189

Viral Evasion of Natural Killer Cell Activation.

PubMed

Ma, Yi; Li, Xiaojuan; Kuang, Ersheng

2016-04-12

Natural killer (NK) cells play a key role in antiviral innate defenses because of their abilities to kill infected cells and secrete regulatory cytokines. Additionally, NK cells exhibit adaptive memory-like antigen-specific responses, which represent a novel antiviral NK cell defense mechanism. Viruses have evolved various strategies to evade the recognition and destruction by NK cells through the downregulation of the NK cell activating receptors. Here, we review the recent findings on viral evasion of NK cells via the impairment of NK cell-activating receptors and ligands, which provide new insights on the relationship between NK cells and viral actions during persistent viral infections.

Strategic Interviewing to Detect Deception: Cues to Deception across Repeated Interviews

PubMed Central

Masip, Jaume; Blandón-Gitlin, Iris; Martínez, Carmen; Herrero, Carmen; Ibabe, Izaskun

2016-01-01

Previous deception research on repeated interviews found that liars are not less consistent than truth tellers, presumably because liars use a “repeat strategy” to be consistent across interviews. The goal of this study was to design an interview procedure to overcome this strategy. Innocent participants (truth tellers) and guilty participants (liars) had to convince an interviewer that they had performed several innocent activities rather than committing a mock crime. The interview focused on the innocent activities (alibi), contained specific central and peripheral questions, and was repeated after 1 week without forewarning. Cognitive load was increased by asking participants to reply quickly. The liars’ answers in replying to both central and peripheral questions were significantly less accurate, less consistent, and more evasive than the truth tellers’ answers. Logistic regression analyses yielded classification rates ranging from around 70% (with consistency as the predictor variable), 85% (with evasive answers as the predictor variable), to over 90% (with an improved measure of consistency that incorporated evasive answers as the predictor variable, as well as with response accuracy as the predictor variable). These classification rates were higher than the interviewers’ accuracy rate (54%). PMID:27847493

A three-state kinetic agent-based model to analyze tax evasion dynamics

NASA Astrophysics Data System (ADS)

Crokidakis, Nuno

2014-11-01

In this work we study the problem of tax evasion on a fully-connected population. For this purpose, we consider that the agents may be in three different states, namely honest tax payers, tax evaders and undecided, that are individuals in an intermediate class among honests and evaders. Every individual can change his/her state following a kinetic exchange opinion dynamics, where the agents interact by pairs with competitive negative (with probability q) and positive (with probability 1-q) couplings, representing agreement/disagreement between pairs of agents. In addition, we consider the punishment rules of the Zaklan econophysics model, for which there is a probability pa of an audit each agent is subject to in every period and a length of time k detected tax evaders remain honest. Our results suggest that below the critical point qc=1/4 of the opinion dynamics the compliance is high, and the punishment rules have a small effect in the population. On the other hand, for q>qc the tax evasion can be considerably reduced by the enforcement mechanism. We also discuss the impact of the presence of the undecided agents in the evolution of the system.

Host Immune Evasion by Lyme and Relapsing Fever Borreliae: Findings to Lead Future Studies for Borrelia miyamotoi

PubMed Central

Stone, Brandee L.; Brissette, Catherine A.

2017-01-01

The emerging pathogen, Borrelia miyamotoi, is a relapsing fever spirochete vectored by the same species of Ixodes ticks that carry the causative agents of Lyme disease in the US, Europe, and Asia. Symptoms caused by infection with B. miyamotoi are similar to a relapsing fever infection. However, B. miyamotoi has adapted to different vectors and reservoirs, which could result in unique physiology, including immune evasion mechanisms. Lyme Borrelia utilize a combination of Ixodes-produced inhibitors and native proteins [i.e., factor H-binding proteins (FHBPs)/complement regulator-acquiring surface proteins, p43, BBK32, BGA66, BGA71, CD59-like protein] to inhibit complement, while some relapsing fever spirochetes use C4b-binding protein and likely Ornithodoros-produced inhibitors. To evade the humoral response, Borrelia utilize antigenic variation of either outer surface proteins (Osps) and the Vmp-like sequences (Vls) system (Lyme borreliae) or variable membrane proteins (Vmps, relapsing fever borreliae). B. miyamotoi possesses putative FHBPs and antigenic variation of Vmps has been demonstrated. This review summarizes and compares the common mechanisms utilized by Lyme and relapsing fever spirochetes, as well as the current state of understanding immune evasion by B. miyamotoi. PMID:28154563

Host Immune Evasion by Lyme and Relapsing Fever Borreliae: Findings to Lead Future Studies for Borrelia miyamotoi.

PubMed

Stone, Brandee L; Brissette, Catherine A

2017-01-01

The emerging pathogen, Borrelia miyamotoi , is a relapsing fever spirochete vectored by the same species of Ixodes ticks that carry the causative agents of Lyme disease in the US, Europe, and Asia. Symptoms caused by infection with B. miyamotoi are similar to a relapsing fever infection. However, B. miyamotoi has adapted to different vectors and reservoirs, which could result in unique physiology, including immune evasion mechanisms. Lyme Borrelia utilize a combination of Ixodes -produced inhibitors and native proteins [i.e., factor H-binding proteins (FHBPs)/complement regulator-acquiring surface proteins, p43, BBK32, BGA66, BGA71, CD59-like protein] to inhibit complement, while some relapsing fever spirochetes use C4b-binding protein and likely Ornithodoros -produced inhibitors. To evade the humoral response, Borrelia utilize antigenic variation of either outer surface proteins (Osps) and the Vmp-like sequences (Vls) system (Lyme borreliae) or variable membrane proteins (Vmps, relapsing fever borreliae). B. miyamotoi possesses putative FHBPs and antigenic variation of Vmps has been demonstrated. This review summarizes and compares the common mechanisms utilized by Lyme and relapsing fever spirochetes, as well as the current state of understanding immune evasion by B. miyamotoi .

Herpes simplex virus-1 evasion of CD8+ T cell accumulation contributes to viral encephalitis.

PubMed

Koyanagi, Naoto; Imai, Takahiko; Shindo, Keiko; Sato, Ayuko; Fujii, Wataru; Ichinohe, Takeshi; Takemura, Naoki; Kakuta, Shigeru; Uematsu, Satoshi; Kiyono, Hiroshi; Maruzuru, Yuhei; Arii, Jun; Kato, Akihisa; Kawaguchi, Yasushi

2017-10-02

Herpes simplex virus-1 (HSV-1) is the most common cause of sporadic viral encephalitis, which can be lethal or result in severe neurological defects even with antiviral therapy. While HSV-1 causes encephalitis in spite of HSV-1-specific humoral and cellular immunity, the mechanism by which HSV-1 evades the immune system in the central nervous system (CNS) remains unknown. Here we describe a strategy by which HSV-1 avoids immune targeting in the CNS. The HSV-1 UL13 kinase promotes evasion of HSV-1-specific CD8+ T cell accumulation in infection sites by downregulating expression of the CD8+ T cell attractant chemokine CXCL9 in the CNS of infected mice, leading to increased HSV-1 mortality due to encephalitis. Direct injection of CXCL9 into the CNS infection site enhanced HSV-1-specific CD8+ T cell accumulation, leading to marked improvements in the survival of infected mice. This previously uncharacterized strategy for HSV-1 evasion of CD8+ T cell accumulation in the CNS has important implications for understanding the pathogenesis and clinical treatment of HSV-1 encephalitis.

Arenavirus Glycan Shield Promotes Neutralizing Antibody Evasion and Protracted Infection

PubMed Central

Malinge, Pauline; Magistrelli, Giovanni; Fischer, Nicolas; Sahin, Mehmet; Bergthaler, Andreas; Igonet, Sebastien; ter Meulen, Jan; Rigo, Dorothée; Meda, Paolo; Rabah, Nadia; Coutard, Bruno; Bowden, Thomas A.; Lambert, Paul-Henri; Siegrist, Claire-Anne; Pinschewer, Daniel D.

2015-01-01

Arenaviruses such as Lassa virus (LASV) can cause severe hemorrhagic fever in humans. As a major impediment to vaccine development, delayed and weak neutralizing antibody (nAb) responses represent a unifying characteristic of both natural infection and all vaccine candidates tested to date. To investigate the mechanisms underlying arenavirus nAb evasion we engineered several arenavirus envelope-chimeric viruses and glycan-deficient variants thereof. We performed neutralization tests with sera from experimentally infected mice and from LASV-convalescent human patients. NAb response kinetics in mice correlated inversely with the N-linked glycan density in the arenavirus envelope protein’s globular head. Additionally and most intriguingly, infection with fully glycosylated viruses elicited antibodies, which neutralized predominantly their glycan-deficient variants, both in mice and humans. Binding studies with monoclonal antibodies indicated that envelope glycans reduced nAb on-rate, occupancy and thereby counteracted virus neutralization. In infected mice, the envelope glycan shield promoted protracted viral infection by preventing its timely elimination by the ensuing antibody response. Thus, arenavirus envelope glycosylation impairs the protective efficacy rather than the induction of nAbs, and thereby prevents efficient antibody-mediated virus control. This immune evasion mechanism imposes limitations on antibody-based vaccination and convalescent serum therapy. PMID:26587982

14 CFR 25.171 - General.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.171 General. The airplane must be.... In addition, suitable stability and control feel (static stability) is required in any condition normally encountered in service, if flight tests show it is necessary for safe operation. [Doc. No. 5066...

14 CFR 25.171 - General.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.171 General. The airplane must be.... In addition, suitable stability and control feel (static stability) is required in any condition normally encountered in service, if flight tests show it is necessary for safe operation. [Doc. No. 5066...

14 CFR 25.171 - General.

Code of Federal Regulations, 2014 CFR

2014-01-01

... STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.171 General. The airplane must be.... In addition, suitable stability and control feel (static stability) is required in any condition normally encountered in service, if flight tests show it is necessary for safe operation. [Doc. No. 5066...

Introduction to the molecular basis of cancer metabolism and the Warburg effect.

PubMed

Ngo, Darleen C; Ververis, Katherine; Tortorella, Stephanie M; Karagiannis, Tom C

2015-04-01

In differentiated normal cells, the conventional route of glucose metabolism involves glycolysis, followed by the citric acid cycle and electron transport chain to generate usable energy in the form of adenosine triphosphate (ATP). This occurs in the presence of oxygen. In hypoxic conditions, normal cells undergo anaerobic glycolysis to yield significantly less energy producing lactate as a product. As first highlighted in the 1920s by Otto Warburg, the metabolism exhibited by tumor cells involves an increased rate of aerobic glycolysis, known as the Warburg effect. In aerobic glycolysis, pyruvate molecules yielded from glycolysis are converted into fewer molecules of ATP even in the presence of oxygen. Evidence indicates that the reasons as to why tumor cells undergo aerobic glycolysis include: (1) the shift in priority to accumulate biomass rather than energy production, (2) the evasion of apoptosis as fewer reactive oxygen species are released by the mitochondria and (3) the production of lactate to further fuel growth of tumors. In this mini-review we discuss emerging molecular aspects of cancer metabolism and the Warburg effect. Aspects of the Warburg effect are analyzed in the context of the established hallmarks of cancer including the role of oncogenes and tumor suppressor genes.

14 CFR 1216.306 - Actions normally requiring an EIS.

Code of Federal Regulations, 2013 CFR

2013-01-01

... normally requiring an EIS. (a) NASA will prepare an EIS for actions with the potential to significantly... action or mitigation of its potentially significant impacts. (b) Typical NASA actions normally requiring... material greater than the quantity for which the NASA Nuclear Flight Safety Assurance Manager may grant...

Plasmacytoid Dendritic Cells: Neglected Regulators of the Immune Response to Staphylococcus aureus

PubMed Central

Bekeredjian-Ding, Isabelle; Greil, Johann; Ammann, Sandra; Parcina, Marijo

2014-01-01

Plasmacytoid dendritic cells (pDC) are a rare subset of leukocytes equipped with Fcγ and Fcε receptors, which exert contrary effects on sensing of microbial nucleic acids by endosomal Toll-like receptors. In this article, we explain how pDC contribute to the immune response to Staphylococcus aureus. Under normal circumstances the pDC participates in the memory response to the pathogen: pDC activation is initiated by uptake of staphylococcal immune complexes with IgG or IgE. However, protein A-expressing S. aureus strains additionally trigger pDC activation in the absence of immunoglobulin. In this context, staphylococci exploit the pDC to induce antigen-independent differentiation of IL-10 producing plasmablasts, an elegant means to propagate immune evasion. We further discuss the role of type I interferons in infection with S. aureus and the implications of these findings for the development of immune based therapies and vaccination. PMID:24904586

Cryptococcus interactions with macrophages: evasion and manipulation of the phagosome by a fungal pathogen.

PubMed

Johnston, Simon A; May, Robin C

2013-03-01

Cryptococcus is a potentially fatal fungal pathogen and a leading cause of death in immunocompromised patients. As an opportunistic and facultative intracellular pathogen of humans, Cryptococcus exhibits a complex set of interactions with the host immune system in general, and macrophages in particular. Cryptococcus is resistant to phagocytosis but is also able to survive and proliferate within the mature phagolysosome. It can cause the lysis of host cells, can be transferred between macrophages or exit non-lytically via vomocytosis. Efficient phagocytosis is reliant on opsonization and Cryptococcus has a number of anti-phagocytic strategies including formation of titan cells and a thick polysaccharide capsule. Following uptake, phagosome maturation appears to occur normally, but the internalized pathogen is able to survive and replicate. Here we review the interactions and host manipulation processes that occur within cryptococcal-infected macrophages and highlight areas for future research. © 2012 Blackwell Publishing Ltd.

Control Systems with Normalized and Covariance Adaptation by Optimal Control Modification

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T. (Inventor); Burken, John J. (Inventor); Hanson, Curtis E. (Inventor)

2016-01-01

Disclosed is a novel adaptive control method and system called optimal control modification with normalization and covariance adjustment. The invention addresses specifically to current challenges with adaptive control in these areas: 1) persistent excitation, 2) complex nonlinear input-output mapping, 3) large inputs and persistent learning, and 4) the lack of stability analysis tools for certification. The invention has been subject to many simulations and flight testing. The results substantiate the effectiveness of the invention and demonstrate the technical feasibility for use in modern aircraft flight control systems.

Estimates of thermochemical relaxation lengths behind normal shock waves relevant to manned lunar and Mars return missions, the aeroassist flight experiment, and Mars entry

NASA Technical Reports Server (NTRS)

Howe, John T.

1991-01-01

Thermochemical relaxation distances behind the strong normal shock waves associated with vehicles that enter the Earth atmosphere upon returning from a manned lunar or Mars mission are estimated. The relaxation distances for a Mars entry are estimated as well, in order to highlight the extent of the relaxation phenomena early in currently envisioned space exploration studies. The thermochemical relaxation length for the Aeroassist Flight Experiment is also considered. These estimates provide an indication as to whether finite relaxation needs to be considered in subsequent detailed analyses. For the Mars entry, relaxation phenomena that are fully coupled to the flow field equations are used. The relaxation-distance estimates can be scaled to flight conditions other than those discussed.

Normal probabilities for Vandenberg AFB wind components - monthly reference periods for all flight azimuths, 0- to 70-km altitudes

NASA Technical Reports Server (NTRS)

Falls, L. W.

1975-01-01

Vandenberg Air Force Base (AFB), California, wind component statistics are presented to be used for aerospace engineering applications that require component wind probabilities for various flight azimuths and selected altitudes. The normal (Gaussian) distribution is presented as a statistical model to represent component winds at Vandenberg AFB. Head tail, and crosswind components are tabulated for all flight azimuths for altitudes from 0 to 70 km by monthly reference periods. Wind components are given for 11 selected percentiles ranging from 0.135 percent to 99.865 percent for each month. The results of statistical goodness-of-fit tests are presented to verify the use of the Gaussian distribution as an adequate model to represent component winds at Vandenberg AFB.

Normal probabilities for Cape Kennedy wind components: Monthly reference periods for all flight azimuths. Altitudes 0 to 70 kilometers

NASA Technical Reports Server (NTRS)

Falls, L. W.

1973-01-01

This document replaces Cape Kennedy empirical wind component statistics which are presently being used for aerospace engineering applications that require component wind probabilities for various flight azimuths and selected altitudes. The normal (Gaussian) distribution is presented as an adequate statistical model to represent component winds at Cape Kennedy. Head-, tail-, and crosswind components are tabulated for all flight azimuths for altitudes from 0 to 70 km by monthly reference periods. Wind components are given for 11 selected percentiles ranging from 0.135 percent to 99,865 percent for each month. Results of statistical goodness-of-fit tests are presented to verify the use of the Gaussian distribution as an adequate model to represent component winds at Cape Kennedy, Florida.

F-15 837 IFCS Intelligent Flight Control System Project

NASA Technical Reports Server (NTRS)

Bosworth, John T.

2007-01-01

This viewgraph presentation reviews the use of Intelligent Flight Control System (IFCS) for the F-15. The goals of the project are: (1) Demonstrate Revolutionary Control Approaches that can Efficiently Optimize Aircraft Performance in both Normal and Failure Conditions (2) Advance Neural Network-Based Flight Control Technology for New Aerospace Systems Designs. The motivation for the development are to reduce the chance and skill required for survival.

The Effect of Mass Distribution on the Lateral Stability and Control Characteristics of an Airplane as Determined by Tests of a Model in the Free-Flight Tunnel

NASA Technical Reports Server (NTRS)

Seacord, Charles L; Campbell, John P.

1943-01-01

The effects of mass distribution on lateral stability and control characteristics of an airplane have been determined by flight tests of a model in the NACA free-flight tunnel. In the investigation, the rolling and yawing movements of inertia were increased from normal values to values up to five times normal. For each moment-of-inertia condition, combinations of dihedral and vertical-tail area representing a variety of airplane configurations were tested. The results of the flight tests of the model were correlated with calculated stability and control characteristics and, in general, good agreement was obtained. The tests showed the following effects of increased rolling and yawing moments of inertia: no appreciable change in spiral stability; reductions in oscillatory stability that were serious at high values of dihedral; a reduction in the sensitivity of the model to gust disturbances; and a reduction in rolling acceleration provided by the ailerons, which caused a marked increase in time to reach a given angle of bank. The general flight behavior of the model became worse with increasing moments of inertia but, with combinations of small effective dihedral and large vertical-tail area, satisfactory flight characteristics were obtained at all moment-of-inertia conditions.

Blocking herpes simplex virus 2 glycoprotein E immune evasion as an approach to enhance efficacy of a trivalent subunit antigen vaccine for genital herpes.

PubMed

Awasthi, Sita; Huang, Jialing; Shaw, Carolyn; Friedman, Harvey M

2014-08-01

Herpes simplex virus 2 (HSV-2) subunit antigen vaccines targeting virus entry molecules have failed to prevent genital herpes in human trials. Our approach is to include a virus entry molecule and add antigens that block HSV-2 immune evasion. HSV-2 glycoprotein C (gC2) is an immune evasion molecule that inhibits complement. We previously reported that adding gC2 to gD2 improved vaccine efficacy compared to the efficacy of either antigen alone in mice and guinea pigs. Here we demonstrate that HSV-2 glycoprotein E (gE2) functions as an immune evasion molecule by binding the IgG Fc domain. HSV-2 gE2 is synergistic with gC2 in protecting the virus from antibody and complement neutralization. Antibodies produced by immunization with gE2 blocked gE2-mediated IgG Fc binding and cell-to-cell spread. Mice immunized with gE2 were only partially protected against HSV-2 vaginal challenge in mice; however, when gE2 was added to gC2/gD2 to form a trivalent vaccine, neutralizing antibody titers with and without complement were significantly higher than those produced by gD2 alone. Importantly, the trivalent vaccine protected the dorsal root ganglia (DRG) of 32/33 (97%) mice between days 2 and 7 postchallenge, compared with 27/33 (82%) in the gD2 group. The HSV-2 DNA copy number was significantly lower in mice immunized with the trivalent vaccine than in those immunized with gD2 alone. The extent of DRG protection using the trivalent vaccine was better than what we previously reported for gC2/gD2 immunization. Therefore, gE2 is a candidate antigen for inclusion in a multivalent subunit vaccine that attempts to block HSV-2 immune evasion. Herpes simplex virus is the most common cause of genital ulcer disease worldwide. Infection results in emotional distress for infected individuals and their partners, is life threatening for infants exposed to herpes during childbirth, and greatly increases the risk of individuals acquiring and transmitting HIV infection. A vaccine that prevents genital herpes infection will have major public health benefits. Our vaccine approach includes strategies to prevent the virus from evading immune attack. Mice were immunized with a trivalent vaccine containing an antigen that induces antibodies to block virus entry and two antigens that induce antibodies that block immune evasion from antibody and complement. Immunized mice demonstrated no genital disease, and 32/33 (97%) animals had no evidence of infection of dorsal root ganglia, suggesting that the vaccine may prevent the establishment of latency and recurrent infections. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

14 CFR 23.365 - Pressurized cabin loads.

Code of Federal Regulations, 2011 CFR

2011-01-01

... landing. (d) The airplane structure must be strong enough to withstand the pressure differential loads... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23... structure must be strong enough to withstand the flight loads combined with pressure differential loads from...

14 CFR 27.674 - Interconnected controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.674 Interconnected controls. Each primary flight control system must provide for safe flight and landing and operate... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Interconnected controls. 27.674 Section 27...

14 CFR 23.1303 - Flight and navigation instruments.

Code of Federal Regulations, 2013 CFR

2013-01-01

... navigation instruments: (a) An airspeed indicator. (b) An altimeter. (c) A magnetic direction indicator. (d... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flight and navigation instruments. 23.1303... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment...

14 CFR 27.674 - Interconnected controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Interconnected controls. 27.674 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.674 Interconnected controls. Each primary flight control system must provide for safe flight and landing and operate...

14 CFR 27.674 - Interconnected controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.674 Interconnected controls. Each primary flight control system must provide for safe flight and landing and operate... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Interconnected controls. 27.674 Section 27...

14 CFR 27.251 - Vibration.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Vibration. 27.251 Section 27.251... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Miscellaneous Flight Requirements § 27.251 Vibration. Each part of the rotorcraft must be free from excessive vibration under each appropriate speed and power...

14 CFR 27.251 - Vibration.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Vibration. 27.251 Section 27.251... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Miscellaneous Flight Requirements § 27.251 Vibration. Each part of the rotorcraft must be free from excessive vibration under each appropriate speed and power...

14 CFR 27.251 - Vibration.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Vibration. 27.251 Section 27.251... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Miscellaneous Flight Requirements § 27.251 Vibration. Each part of the rotorcraft must be free from excessive vibration under each appropriate speed and power...

14 CFR 27.251 - Vibration.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration. 27.251 Section 27.251... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Miscellaneous Flight Requirements § 27.251 Vibration. Each part of the rotorcraft must be free from excessive vibration under each appropriate speed and power...

14 CFR 27.251 - Vibration.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Vibration. 27.251 Section 27.251... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Miscellaneous Flight Requirements § 27.251 Vibration. Each part of the rotorcraft must be free from excessive vibration under each appropriate speed and power...

Inhibited interferon production after space flight

NASA Technical Reports Server (NTRS)

Sonnenfeld, G.; Gould, C. L.; Williams, J.; Mandel, A. D.

1988-01-01

Several studies have been performed in our laboratories indicating that interferon production may be impaired in rodents after space flight. Using an antiorthostatic suspension model that simulates some of the effects of microgravity seen during space flight, we have shown that interferon-alpha/beta production was inhibited. The inhibition was not due solely to the stress of suspension. The inhibited interferon production was transient, as suspended animals returned to normal caging recovered the ability to produce interferon. Antiorthostatic suspension of mice also resulted in a loss of resistance to infection with the diabetogenic strain of encephalomyocarditis virus, which correlated with the drop in interferon production. In rats flown in US Space Shuttle mission SL-3, interferon-gamma production was inhibited severely when spleen cells were challenged with concanavalin-A upon return to earth. In contrast, interleukin-3 production by these cells was normal. These results suggest that immune responses may be altered after antiorthostatic modeling or space flight, and the resistance to viral infections may be especially affected.

Characteristics of random inlet pressure fluctuations during flights of F-111A airplane

NASA Technical Reports Server (NTRS)

Costakis, W. G.

1977-01-01

Compressor face dynamic total pressures from four F-111 flights were analyzed. Statistics of the nonstationary data were investigated by analyzing the data in a quasi-stationary manner. Changes in the character of the dynamic signal are investigated as functions of flight conditions, time in flight, and location at the compressor face. The results, which are presented in the form of rms values, histograms, and power spectrum plots, show that the shape of the power spectra remains relatively flat while the histograms have an approximate normal distribution.

USAF bioenvironmental noise data handbook. Volume 148. T-37B in-flight crew noise

NASA Astrophysics Data System (ADS)

Hille, H. K.

1981-11-01

The T-37B is a USAF two-seat primary trainer aircraft. This report provides measured data defining the bioacoustic environments at flight crew/passenger locations inside this aircraft during normal flight operations. Data are reported at one location for 19 different flight conditions and psychoacoustic measures: overall and band sound pressure levels, C-weighted and A-weighted sound levels, preferred speech interference level, perceived noise level, and limiting times for total daily exposure of personnel with and without standard Air Force ear protectors.

Low Gravity Freefall Facilities

NASA Technical Reports Server (NTRS)

1981-01-01

Composite of Marshall Space Flight Center's Low-Gravity Free Fall Facilities.These facilities include a 100-meter drop tower and a 100-meter drop tube. The drop tower simulates in-flight microgravity conditions for up to 4.2 seconds for containerless processing experiments, immiscible fluids and materials research, pre-flight hardware design test and flight experiment simulation. The drop tube simulates in-flight microgravity conditions for up to 4.6 seconds and is used extensively for ground-based microgravity convection research in which extremely small samples are studied. The facility can provide deep undercooling for containerless processing experiments that require materials to remain in a liquid phase when cooled below the normal solidification temperature.

Microgravity

NASA Image and Video Library

1981-03-30

Composite of Marshall Space Flight Center's Low-Gravity Free Fall Facilities.These facilities include a 100-meter drop tower and a 100-meter drop tube. The drop tower simulates in-flight microgravity conditions for up to 4.2 seconds for containerless processing experiments, immiscible fluids and materials research, pre-flight hardware design test and flight experiment simulation. The drop tube simulates in-flight microgravity conditions for up to 4.6 seconds and is used extensively for ground-based microgravity convection research in which extremely small samples are studied. The facility can provide deep undercooling for containerless processing experiments that require materials to remain in a liquid phase when cooled below the normal solidification temperature.

Manual Manipulation of Engine Throttles for Emergency Flight Control

NASA Technical Reports Server (NTRS)

Burcham, Frank W., Jr.; Fullerton, C. Gordon; Maine, Trindel A.

2004-01-01

If normal aircraft flight controls are lost, emergency flight control may be attempted using only engines thrust. Collective thrust is used to control flightpath, and differential thrust is used to control bank angle. Flight test and simulation results on many airplanes have shown that pilot manipulation of throttles is usually adequate to maintain up-and-away flight, but is most often not capable of providing safe landings. There are techniques that will improve control and increase the chances of a survivable landing. This paper reviews the principles of throttles-only control (TOC), a history of accidents or incidents in which some or all flight controls were lost, manual TOC results for a wide range of airplanes from simulation and flight, and suggested techniques for flying with throttles only and making a survivable landing.

14 CFR 29.927 - Additional tests.

Code of Federal Regulations, 2012 CFR

2012-01-01

... controlled by the pilot under normal operating conditions (such as where the primary engine power control is accomplished through the flight control), the following test must be made: (1) Under conditions associated with... applicant for continued flight, for at least 30 minutes after perception by the flightcrew of the...

14 CFR 23.251 - Vibration and buffeting.

Code of Federal Regulations, 2013 CFR

2013-01-01

... must be no buffeting in any normal flight condition, including configuration changes during cruise, severe enough to interfere with the satisfactory control of the airplane or cause excessive fatigue to... perceptible buffeting condition in the cruise configuration in straight flight at any speed up to VMO/MMO...

14 CFR 23.251 - Vibration and buffeting.

Code of Federal Regulations, 2014 CFR

2014-01-01

... must be no buffeting in any normal flight condition, including configuration changes during cruise, severe enough to interfere with the satisfactory control of the airplane or cause excessive fatigue to... perceptible buffeting condition in the cruise configuration in straight flight at any speed up to VMO/MMO...

14 CFR 23.77 - Balked landing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... of more than 6,000 pounds maximum weight and each normal, utility, and acrobatic category turbine... movement of the power controls from minimum flight-idle position; (2) The landing gear extended; (3) The... of movement of the power controls from the minimum flight idle position; (2) Landing gear extended...

14 CFR 23.231 - Longitudinal stability and control.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Ground... rebound during landing or takeoff. Wheel brakes must operate smoothly and may not induce any undue... characteristics at any normal operating speed on the water. ...

14 CFR 23.231 - Longitudinal stability and control.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Ground... rebound during landing or takeoff. Wheel brakes must operate smoothly and may not induce any undue... characteristics at any normal operating speed on the water. ...

14 CFR 23.231 - Longitudinal stability and control.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Ground... rebound during landing or takeoff. Wheel brakes must operate smoothly and may not induce any undue... characteristics at any normal operating speed on the water. ...

14 CFR 23.231 - Longitudinal stability and control.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Ground... rebound during landing or takeoff. Wheel brakes must operate smoothly and may not induce any undue... characteristics at any normal operating speed on the water. ...

14 CFR 23.231 - Longitudinal stability and control.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Ground... rebound during landing or takeoff. Wheel brakes must operate smoothly and may not induce any undue... characteristics at any normal operating speed on the water. ...

Determining density of maize canopy. 3: Temporal considerations

NASA Technical Reports Server (NTRS)

Stoner, E. R.; Baumgardner, M. F.; Anuta, P. E.; Cipra, J. E.

1972-01-01

Multispectral scanner data were collected in two flights over ground cover plots at an altitude of 305 m. Eight ground reflectance panels in close proximity to the ground cover plots were used to normalize the scanner data obtained on different dates. Separate prediction equations were obtained for both flight dates for all eleven reflective wavelength bands of the multispectral scanner. Ratios of normalized scanner data were related to leaf area index over time. Normalized scanner data were used to plot relative reflectance versus wavelength for the ground cover plots. Spectral response curves were similar to those for bare soil and green vegetation as determined by laboratory measurements. The spectral response curves from the normalized scanner data indicated that reflectance in the 0.72 to 1.3 micron wavelength range increased as leaf area index increased. A decrease in reflectance was observed in the 0.65 micron chlorophyll absorption band as leaf area index increased.

Planning strategies for development of effective exercise and nutrition countermeasures for long-duration space flight

NASA Technical Reports Server (NTRS)

Convertino, Victor A.

2002-01-01

Exercise and nutrition represent primary countermeasures used during space flight to maintain or restore maximal aerobic capacity, musculoskeletal structure, and orthostatic function. However, no single exercise, dietary regimen, or combination of prescriptions has proven entirely effective in maintaining or restoring cardiovascular and musculoskeletal functions to preflight levels after prolonged space flight. As human space flight exposures increase in duration, identification, assessment, and development of various effective exercise- and nutrition-based protective procedures will become paramount. The application of adequate dietary intake in combination with effective exercise prescription will be based on identification of basic physiologic stimuli that maintain normal function in terrestrial gravity, and understanding how specific combinations of exercise characteristics (e.g., duration, frequency, intensity, and mode) can be combined with minimal nutritional requirements that mimic the stimuli normally produced by living in Earth's gravity environment. This can be accomplished only with greater emphasis of research on ground-based experiments targeted at understanding the interactions between caloric intake and expenditure during space flight. Future strategies for application of nutrition and exercise countermeasures for long-duration space missions must be directed to minimizing crew time and the impact on life-support resources.

Planning strategies for development of effective exercise and nutrition countermeasures for long-duration space flight.

PubMed

Convertino, Victor A

2002-10-01

Exercise and nutrition represent primary countermeasures used during space flight to maintain or restore maximal aerobic capacity, musculoskeletal structure, and orthostatic function. However, no single exercise, dietary regimen, or combination of prescriptions has proven entirely effective in maintaining or restoring cardiovascular and musculoskeletal functions to preflight levels after prolonged space flight. As human space flight exposures increase in duration, identification, assessment, and development of various effective exercise- and nutrition-based protective procedures will become paramount. The application of adequate dietary intake in combination with effective exercise prescription will be based on identification of basic physiologic stimuli that maintain normal function in terrestrial gravity, and understanding how specific combinations of exercise characteristics (e.g., duration, frequency, intensity, and mode) can be combined with minimal nutritional requirements that mimic the stimuli normally produced by living in Earth's gravity environment. This can be accomplished only with greater emphasis of research on ground-based experiments targeted at understanding the interactions between caloric intake and expenditure during space flight. Future strategies for application of nutrition and exercise countermeasures for long-duration space missions must be directed to minimizing crew time and the impact on life-support resources.

Shuttle remote manipulator system mission preparation and operations

NASA Technical Reports Server (NTRS)

Smith, Ernest E., Jr.

1989-01-01

The preflight planning, analysis, procedures development, and operations support for the Space Transportation System payload deployment and retrieval missions utilizing the Shuttle Remote Manipulator System are summarized. Analysis of the normal operational loads and failure induced loads and motion are factored into all procedures. Both the astronaut flight crews and the Mission Control Center flight control teams receive considerable training for standard and mission specific operations. The real time flight control team activities are described.

The FLIGHT Drosophila RNAi database

PubMed Central

Bursteinas, Borisas; Jain, Ekta; Gao, Qiong; Baum, Buzz; Zvelebil, Marketa

2010-01-01

FLIGHT (http://flight.icr.ac.uk/) is an online resource compiling data from high-throughput Drosophila in vivo and in vitro RNAi screens. FLIGHT includes details of RNAi reagents and their predicted off-target effects, alongside RNAi screen hits, scores and phenotypes, including images from high-content screens. The latest release of FLIGHT is designed to enable users to upload, analyze, integrate and share their own RNAi screens. Users can perform multiple normalizations, view quality control plots, detect and assign screen hits and compare hits from multiple screens using a variety of methods including hierarchical clustering. FLIGHT integrates RNAi screen data with microarray gene expression as well as genomic annotations and genetic/physical interaction datasets to provide a single interface for RNAi screen analysis and datamining in Drosophila. PMID:20855970

Recent findings in cardiovascular physiology with space travel.

PubMed

Hughson, Richard L

2009-10-01

The cardiovascular system undergoes major changes in stress with space flight primarily related to the elimination of the head-to-foot gravitational force. A major observation has been that the central venous pressure is not elevated early in space flight yet stroke volume is increased at least early in flight. Recent observations demonstrate that heart rate remains lower during the normal daily activities of space flight compared to Earth-based conditions. Structural and functional adaptations occur in the vascular system that could result in impaired response with demands of physical exertion and return to Earth. Cardiac muscle mass is reduced after flight and contractile function may be altered. Regular and specific countermeasures are essential to maintain cardiovascular health during long-duration space flight.

Reduced G tolerance associated with supplement use.

PubMed

Barker, Patrick D

2011-02-01

High G forces encountered in tactical military aviation and aerobatic flight produce a host of physiologic responses aimed at preserving cerebral perfusion. The military has instituted measures to augment the physiologic response in order to avoid G-induced loss of consciousness (G-LOC) because of its potential to cause a catastrophic mishap. The case presented here details a Naval Aviator who experienced reduced G tolerance over two successive flights with a temporal relationship of starting a new supplement. Two components of the supplement, coenzyme Q10 and niacin, are highlighted here for their hemodynamic effects. After stopping the supplement the aviator regained his normal G tolerance and had no further issues in flight. There are several factors that can reduce G tolerance and supplement use has to be considered here because of the potential for altering the normal physiological response to increased G force. Our discussion reviews the physiological effects of increased G force, the spectrum of signs of decompensation under the stress of G force, and the potential effects this supplement had on the normal physiological response to increased G force, thus reducing the aviator's G tolerance.

Restricted sleep and negative affective states in commercial pilots during short haul operations.

PubMed

Drury, D Arthur; Ferguson, Sally A; Thomas, Matthew J W

2012-03-01

This study aims to investigate (1) the relationship between restricted sleep and Heightened Emotional Activity (HEA) during normal flight operations, and (2) whether sleep patterns influence the strength of the HEA as a response to threats. Accident investigation reports continue to highlight the relationship between restricted sleep and poor safety outcomes. However, to date we have a limited understanding of how sleep and HEA interact. A total of 302 sectors of normal airline flight operations were observed by trained observers, and instances of heightened emotional activity were recorded. During the cruise phase of each of these sectors, crew members were asked to calculate the amount of sleep they had obtained in previous 24 and 48 h. In the 302 sectors of normal flight operations, 535 instances of HEA were observed. Descriptive analyses of instances of HEA and sleep in the prior 24 and 48 h showed a significant relationship between the occurrence of HEA and recent sleep. The relationship between restricted sleep and HEA suggests that there may well be further implications with respect to operational safety. Copyright © 2011 Elsevier Ltd. All rights reserved.

Factor Analysis of Therapist-Identified Treatment Targets in Community-Based Children's Mental Health.

PubMed

Love, Allison R; Okado, Izumi; Orimoto, Trina E; Mueller, Charles W

2018-01-01

The present study used exploratory and confirmatory factor analyses to identify underlying latent factors affecting variation in community therapists' endorsement of treatment targets. As part of a statewide practice management program, therapist completed monthly reports of treatment targets (up to 10 per month) for a sample of youth (n = 790) receiving intensive in-home therapy. Nearly 75 % of youth were diagnosed with multiple co-occurring disorders. Five factors emerged: Disinhibition, Societal Rules Evasion, Social Engagement Deficits, Emotional Distress, and Management of Biodevelopmental Outcomes. Using logistic regression, primary diagnosis predicted therapist selection of Disinhibition and Emotional Distress targets. Client age predicted endorsement of Societal Rules Evasion targets. Practice-to-research implications are discussed.

Effect of perceived threat on avoidance maneuvers selected while viewing cockpit traffic displays

NASA Technical Reports Server (NTRS)

Smith, J. D.; Ellis, S. R.

1982-01-01

Ten airline pilots rated the collision danger of air traffic presented on cockpit displays of traffic information (CDTI) while they monitored simulated departures from Denver. They selected avoidance maneuvers when necessary for separation. Most evasive maneuvers were turns rather than vertical maneuvers. Evasive maneuvers chosen for encounters with low or moderate perceived collision danger were generally toward the intruding aircraft. This tendency lessened as the perceived threat level increased. In the highest threat situations pilots turned toward the intruder only at chance levels. Some of the implications of the pilots' turning-towards tendencies are discussed with respect to automatic collision avoidance systems and coordination of avoidance maneuvers of conflicting aircraft.

78 FR 75285 - Special Conditions: Bombardier Inc., Models BD-500-1A10 and BD-500-1A11 Series Airplanes; Flight...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-11

... must not be less than: (1) 2.5g for the normal state of the electronic flight control system with the... speeds. For the FAA to consider a trajectory change as satisfactory, the applicant should propose and...

14 CFR 27.927 - Additional tests.

Code of Federal Regulations, 2012 CFR

2012-01-01

... controlled by the pilot under normal operating conditions (such as where the primary engine power control is accomplished through the flight control), the following test must be made: (1) Under conditions associated with... the torque must be absorbed by the rotors to be installed, except that other ground or flight test...

14 CFR 27.927 - Additional tests.

Code of Federal Regulations, 2011 CFR

2011-01-01

... controlled by the pilot under normal operating conditions (such as where the primary engine power control is accomplished through the flight control), the following test must be made: (1) Under conditions associated with... the torque must be absorbed by the rotors to be installed, except that other ground or flight test...

14 CFR 23.181 - Dynamic stability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Dynamic stability. 23.181 Section 23.181... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Stability § 23.181 Dynamic... that the function of a stability augmentation system, reference § 23.672, is needed to meet the flight...

14 CFR 23.201 - Wings level stall.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Wings level stall. 23.201 Section 23.201... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight Stalls § 23.201 Wings level... airplane stalls. (b) The wings level stall characteristics must be demonstrated in flight as follows...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2010 CFR

2010-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2014 CFR

2014-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2012 CFR

2012-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2013 CFR

2013-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR 135.340 - Initial and transition training and checking: Flight instructors (aircraft), flight instructors...

Code of Federal Regulations, 2011 CFR

2011-01-01

... principles of the teaching-learning process; (ii) Teaching methods and procedures; and (iii) The instructor... certificate holder's policies and procedures. (3) The applicable methods, procedures, and techniques for... approved methods, procedures, and limitations for performing the required normal, abnormal, and emergency...

14 CFR Appendix E to Part 141 - Airline Transport Pilot Certification Course

Code of Federal Regulations, 2012 CFR

2012-01-01

... performance in normal and abnormal flight regimes; (11) Human factors; (12) Aeronautical decision making and judgment; and (13) Crew resource management to include crew communication and coordination. 4. Flight... contracting State to the Convention on International Civil Aviation. 3. Aeronautical knowledge areas. (a) Each...

14 CFR Appendix E to Part 141 - Airline Transport Pilot Certification Course

Code of Federal Regulations, 2013 CFR

2013-01-01

... performance in normal and abnormal flight regimes; (11) Human factors; (12) Aeronautical decision making and judgment; and (13) Crew resource management to include crew communication and coordination. 4. Flight... contracting State to the Convention on International Civil Aviation. 3. Aeronautical knowledge areas. (a) Each...

14 CFR Appendix E to Part 141 - Airline Transport Pilot Certification Course

Code of Federal Regulations, 2014 CFR

2014-01-01

... performance in normal and abnormal flight regimes; (11) Human factors; (12) Aeronautical decision making and judgment; and (13) Crew resource management to include crew communication and coordination. 4. Flight... contracting State to the Convention on International Civil Aviation. 3. Aeronautical knowledge areas. (a) Each...

The Naturalistic Flight Deck System: An Integrated System Concept for Improved Single-Pilot Operations

NASA Technical Reports Server (NTRS)

Schutte, Paul C.; Goodrich, Kenneth H.; Cox, David E.; Jackson, Bruce; Palmer, Michael T.; Pope, Alan T.; Schlecht, Robin W.; Tedjojuwono, Ken K.; Trujillo, Anna C.; Williams, Ralph A.;

Interior near-field acoustical holography in flight.

PubMed

Williams, E G; Houston, B H; Herdic, P C; Raveendra, S T; Gardner, B

2000-10-01

In this paper boundary element methods (BEM) are mated with near-field acoustical holography (NAH) in order to determine the normal velocity over a large area of a fuselage of a turboprop airplane from a measurement of the pressure (hologram) on a concentric surface in the interior of the aircraft. This work represents the first time NAH has been applied in situ, in-flight. The normal fuselage velocity was successfully reconstructed at the blade passage frequency (BPF) of the propeller and its first two harmonics. This reconstructed velocity reveals structure-borne and airborne sound-transmission paths from the engine to the interior space.

Full-Scale Tests of NACA Cowlings

NASA Technical Reports Server (NTRS)

Theodorsen, Theodore; Brevoort, M J; Stickle, George W

1937-01-01

A comprehensive investigation has been carried on with full-scale models in the NACA 20-foot wind tunnel, the general purpose of which is to furnish information in regard to the physical functioning of the composite propeller-nacelle unit under all conditions of take-off, taxiing, and normal flight. This report deals exclusively with the cowling characteristics under condition of normal flight and includes the results of tests of numerous combinations of more than a dozen nose cowlings, about a dozen skirts, two propellers, two sizes of nacelle, as well as various types of spinners and other devices.

An analysis of life expectancy of airplane wings in normal cruising flight

NASA Technical Reports Server (NTRS)

Putnam, Abbott A

1945-01-01

In order to provide a basis for judging the relative importance of wing failure by fatigue and by single intense gusts, an analysis of wing life for normal cruising flight was made based on data on the frequency of atmospheric gusts. The independent variables considered in the analysis included stress-concentration factor, stress-load relation, wing loading, design and cruising speeds, design gust velocity, and airplane size. Several methods for estimating fatigue life from gust frequencies are discussed. The procedure selected for the analysis is believed to be simple and reasonably accurate, though slightly conservative.

[Characteristics of bone tissue of rats after flight aboard biosputnik Kosmos-1129].

PubMed

Rogacheva, I V; Stupakov, G P; Volozhin, A I; Pavlova, M N; Poliakov, A N

1984-01-01

Bones of rats flown for 19 days onboard Cosmos-1129 were examined. The examination included bone mass, density, mineral composition, reconstruction parameters, and elemental composition at R + 1, R + 6, and R + 29. After flight the rats developed osteoporosis in the spongy structures of tubular bones and a smaller thickness of the cortical layer of the diaphysis; they showed no mineralization of the microstructures, a slight decrease of the Ca concentration, and a normal content of P. At R + 6 these changes progressively developed and at R + 29 they returned to normal.

Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges

PubMed Central

Nielsen, Travis B.; Bonomo, Robert A.; Pantapalangkoor, Paul; Luna, Brian; Spellberg, Brad

2016-01-01

SUMMARY Acinetobacter is a complex genus, and historically, there has been confusion about the existence of multiple species. The species commonly cause nosocomial infections, predominantly aspiration pneumonia and catheter-associated bacteremia, but can also cause soft tissue and urinary tract infections. Community-acquired infections by Acinetobacter spp. are increasingly reported. Transmission of Acinetobacter and subsequent disease is facilitated by the organism's environmental tenacity, resistance to desiccation, and evasion of host immunity. The virulence properties demonstrated by Acinetobacter spp. primarily stem from evasion of rapid clearance by the innate immune system, effectively enabling high bacterial density that triggers lipopolysaccharide (LPS)–Toll-like receptor 4 (TLR4)-mediated sepsis. Capsular polysaccharide is a critical virulence factor that enables immune evasion, while LPS triggers septic shock. However, the primary driver of clinical outcome is antibiotic resistance. Administration of initially effective therapy is key to improving survival, reducing 30-day mortality threefold. Regrettably, due to the high frequency of this organism having an extreme drug resistance (XDR) phenotype, early initiation of effective therapy is a major clinical challenge. Given its high rate of antibiotic resistance and abysmal outcomes (up to 70% mortality rate from infections caused by XDR strains in some case series), new preventative and therapeutic options for Acinetobacter spp. are desperately needed. PMID:27974412

Diagnostic Evasion of Highly-Resistant Microorganisms: A Critical Factor in Nosocomial Outbreaks.

PubMed

Zhou, Xuewei; Friedrich, Alexander W; Bathoorn, Erik

2017-01-01

Highly resistant microorganisms (HRMOs) may evade screening strategies used in routine diagnostics. Bacteria that have evolved to evade diagnostic tests may have a selective advantage in the nosocomial environment. Evasion of resistance detection can result from the following mechanisms: low-level expression of resistance genes not resulting in detectable resistance, slow growing variants, mimicry of wild-type-resistance, and resistance mechanisms that are only detected if induced by antibiotic pressure. We reviewed reports on hospital outbreaks in the Netherlands over the past 5 years. Remarkably, many outbreaks including major nation-wide outbreaks were caused by microorganisms able to evade resistance detection by diagnostic screening tests. We describe various examples of diagnostic evasion by several HRMOs and discuss this in a broad and international perspective. The epidemiology of hospital-associated bacteria may strongly be affected by diagnostic screening strategies. This may result in an increasing reservoir of resistance genes in hospital populations that is unnoticed. The resistance elements may horizontally transfer to hosts with systems for high-level expression, resulting in a clinically significant resistance problem. We advise to communicate the identification of HRMOs that evade diagnostics within national and regional networks. Such signaling networks may prevent inter-hospital outbreaks, and allow collaborative development of adapted diagnostic tests.

A CRISPR-Cas system enhances envelope integrity mediating antibiotic resistance and inflammasome evasion

PubMed Central

Sampson, Timothy R.; Napier, Brooke A.; Schroeder, Max R.; Louwen, Rogier; Zhao, Jinshi; Chin, Chui-Yoke; Ratner, Hannah K.; Llewellyn, Anna C.; Jones, Crystal L.; Laroui, Hamed; Merlin, Didier; Zhou, Pei; Endtz, Hubert P.; Weiss, David S.

2014-01-01

Clustered, regularly interspaced, short palindromic repeats–CRISPR associated (CRISPR-Cas) systems defend bacteria against foreign nucleic acids, such as during bacteriophage infection and transformation, processes which cause envelope stress. It is unclear if these machineries enhance membrane integrity to combat this stress. Here, we show that the Cas9-dependent CRISPR-Cas system of the intracellular bacterial pathogen Francisella novicida is involved in enhancing envelope integrity through the regulation of a bacterial lipoprotein. This action ultimately provides increased resistance to numerous membrane stressors, including antibiotics. We further find that this previously unappreciated function of Cas9 is critical during infection, as it promotes evasion of the host innate immune absent in melanoma 2/apoptosis associated speck-like protein containing a CARD (AIM2/ASC) inflammasome. Interestingly, the attenuation of the cas9 mutant is complemented only in mice lacking both the AIM2/ASC inflammasome and the bacterial lipoprotein sensor Toll-like receptor 2, but not in single knockout mice, demonstrating that Cas9 is essential for evasion of both pathways. These data represent a paradigm shift in our understanding of the function of CRISPR-Cas systems as regulators of bacterial physiology and provide a framework with which to investigate the roles of these systems in myriad bacteria, including pathogens and commensals. PMID:25024199

More than just immune evasion: Hijacking complement by Plasmodium falciparum.

PubMed

Schmidt, Christoph Q; Kennedy, Alexander T; Tham, Wai-Hong

2015-09-01

Malaria remains one of the world's deadliest diseases. Plasmodium falciparum is responsible for the most severe and lethal form of human malaria. P. falciparum's life cycle involves two obligate hosts: human and mosquito. From initial entry into these hosts, malaria parasites face the onslaught of the first line of host defence, the complement system. In this review, we discuss the complex interaction between complement and malaria infection in terms of hosts immune responses, parasite survival and pathogenesis of severe forms of malaria. We will focus on the role of complement receptor 1 and its associated polymorphisms in malaria immune complex clearance, as a mediator of parasite rosetting and as an entry receptor for P. falciparum invasion. Complement evasion strategies of P. falciparum parasites will also be highlighted. The sexual forms of the malaria parasites recruit the soluble human complement regulator Factor H to evade complement-mediated killing within the mosquito host. A novel evasion strategy is the deployment of parasite organelles to divert complement attack from infective blood stage parasites. Finally we outline the future challenge to understand the implications of these exploitation mechanisms in the interplay between successful infection of the host and pathogenesis observed in severe malaria. Copyright © 2015 Elsevier Ltd. All rights reserved.

A CRISPR-Cas system enhances envelope integrity mediating antibiotic resistance and inflammasome evasion.

PubMed

Sampson, Timothy R; Napier, Brooke A; Schroeder, Max R; Louwen, Rogier; Zhao, Jinshi; Chin, Chui-Yoke; Ratner, Hannah K; Llewellyn, Anna C; Jones, Crystal L; Laroui, Hamed; Merlin, Didier; Zhou, Pei; Endtz, Hubert P; Weiss, David S

2014-07-29

Clustered, regularly interspaced, short palindromic repeats-CRISPR associated (CRISPR-Cas) systems defend bacteria against foreign nucleic acids, such as during bacteriophage infection and transformation, processes which cause envelope stress. It is unclear if these machineries enhance membrane integrity to combat this stress. Here, we show that the Cas9-dependent CRISPR-Cas system of the intracellular bacterial pathogen Francisella novicida is involved in enhancing envelope integrity through the regulation of a bacterial lipoprotein. This action ultimately provides increased resistance to numerous membrane stressors, including antibiotics. We further find that this previously unappreciated function of Cas9 is critical during infection, as it promotes evasion of the host innate immune absent in melanoma 2/apoptosis associated speck-like protein containing a CARD (AIM2/ASC) inflammasome. Interestingly, the attenuation of the cas9 mutant is complemented only in mice lacking both the AIM2/ASC inflammasome and the bacterial lipoprotein sensor Toll-like receptor 2, but not in single knockout mice, demonstrating that Cas9 is essential for evasion of both pathways. These data represent a paradigm shift in our understanding of the function of CRISPR-Cas systems as regulators of bacterial physiology and provide a framework with which to investigate the roles of these systems in myriad bacteria, including pathogens and commensals.

Evasion of immunosurveillance by genomic alterations of PPARγ/RXRα in bladder cancer.

PubMed

Korpal, Manav; Puyang, Xiaoling; Jeremy Wu, Zhenhua; Seiler, Roland; Furman, Craig; Oo, Htoo Z; Seiler, Michael; Irwin, Sean; Subramanian, Vanitha; Julie Joshi, Jaya; Wang, Chris K; Rimkunas, Victoria; Tortora, Davide; Yang, Hua; Kumar, Namita; Kuznetsov, Galina; Matijevic, Mark; Chow, Jesse; Kumar, Pavan; Zou, Jian; Feala, Jacob; Corson, Laura; Henry, Ryan; Selvaraj, Anand; Davis, Allison; Bloudoff, Kristjan; Douglas, James; Kiss, Bernhard; Roberts, Morgan; Fazli, Ladan; Black, Peter C; Fekkes, Peter; Smith, Peter G; Warmuth, Markus; Yu, Lihua; Hao, Ming-Hong; Larsen, Nicholas; Daugaard, Mads; Zhu, Ping

2017-07-24

Muscle-invasive bladder cancer (MIBC) is an aggressive disease with limited therapeutic options. Although immunotherapies are approved for MIBC, the majority of patients fail to respond, suggesting existence of complementary immune evasion mechanisms. Here, we report that the PPARγ/RXRα pathway constitutes a tumor-intrinsic mechanism underlying immune evasion in MIBC. Recurrent mutations in RXRα at serine 427 (S427F/Y), through conformational activation of the PPARγ/RXRα heterodimer, and focal amplification/overexpression of PPARγ converge to modulate PPARγ/RXRα-dependent transcription programs. Immune cell-infiltration is controlled by activated PPARγ/RXRα that inhibits expression/secretion of inflammatory cytokines. Clinical data sets and an in vivo tumor model indicate that PPARγ High /RXRα S427F/Y impairs CD8 + T-cell infiltration and confers partial resistance to immunotherapies. Knockdown of PPARγ or RXRα and pharmacological inhibition of PPARγ significantly increase cytokine expression suggesting therapeutic approaches to reviving immunosurveillance and sensitivity to immunotherapies. Our study reveals a class of tumor cell-intrinsic "immuno-oncogenes" that modulate the immune microenvironment of cancer.Muscle-invasive bladder cancer (MIBC) is a potentially lethal disease. Here the authors characterize diverse genetic alterations in MIBC that convergently lead to constitutive activation of PPARgamma/RXRalpha and result in immunosurveillance escape by inhibiting CD8+ T-cell recruitment.

Evasion of Neutrophil Extracellular Traps by Respiratory Pathogens

PubMed Central

Storisteanu, Daniel M. L.; Pocock, Joanna M.; Cowburn, Andrew S.; Juss, Jatinder K.; Nadesalingam, Angalee; Nizet, Victor

2017-01-01

The release of neutrophil extracellular traps (NETs) is a major immune mechanism intended to capture pathogens. These histone- and protease-coated DNA structures are released by neutrophils in response to a variety of stimuli, including respiratory pathogens, and have been identified in the airways of patients with respiratory infection, cystic fibrosis, acute lung injury, primary graft dysfunction, and chronic obstructive pulmonary disease. NET production has been demonstrated in the lungs of mice infected with Staphylococcus aureus, Klebsiella pneumoniae, and Aspergillus fumigatus. Since the discovery of NETs over a decade ago, evidence that “NET evasion” might act as an immune protection strategy among respiratory pathogens, including group A Streptococcus, Bordetella pertussis, and Haemophilus influenzae, has been growing, with the majority of these studies being published in the past 2 years. Evasion strategies fall into three main categories: inhibition of NET release by down-regulating host inflammatory responses; degradation of NETs using pathogen-derived DNases; and resistance to the microbicidal components of NETs, which involves a variety of mechanisms, including encapsulation. Hence, the evasion of NETs appears to be a widespread strategy to allow pathogen proliferation and dissemination, and is currently a topic of intense research interest. This article outlines the evidence supporting the three main strategies of NET evasion—inhibition, degradation, and resistance—with particular reference to common respiratory pathogens. PMID:27854516

Herpesvirus microRNAs for use in gene therapy immune-evasion strategies.

PubMed

Bots, S T F; Hoeben, R C

2017-07-01

Transplantation of allogeneic cells as well as of genetically corrected autologous cells are potent approaches to restore cellular functions in patients suffering from genetic diseases. The recipient's immune responses against non-self-antigens may compromise the survival of the grafted cells. Recipients of the graft may therefore require lifelong treatment with immunosuppressive drugs. An alternative approach to reduce graft rejection could involve the use of immune-evasion molecules. Expression of such molecules in cells of the graft may subvert recognition by the host's immune system. Viruses in particular are masters of exploitation and modulation of their hosts immune response. The Herpesviridae family provides a proof of concept for this as these viruses are capable to establish latency and a lifelong persistence in the infected hosts. While several viral proteins involved in immune evasion have been characterized, the Herpesviridae also encode a multitude of viral microRNA (miRNAs). Several of these miRNAs have been demonstrated to reduce the sensitivity of the infected cells to the destructive action of the host's immune cells. In this review, the miRNAs of some common herpesviruses that are associated with immune modulation will be discussed with a focus on their potential use in strategies aiming at generating non-immunogenic cells for transplantation.

Mercury evasion from a boreal peatland shortens the timeline for recovery from legacy pollution.

PubMed

Osterwalder, Stefan; Bishop, Kevin; Alewell, Christine; Fritsche, Johannes; Laudon, Hjalmar; Åkerblom, Staffan; Nilsson, Mats B

2017-11-22

Peatlands are a major source of methylmercury that contaminates downstream aquatic food webs. The large store of mercury (Hg) in peatlands could be a source of Hg for over a century even if deposition is dramatically reduced. However, the reliability of Hg mass balances can be questioned due to missing long-term land-atmosphere flux measurements. We used a novel micrometeorological system for continuous measurement of Hg peatland-atmosphere exchange to derive the first annual Hg budget for a peatland. The evasion of Hg (9.4 µg m -2 yr -1 ) over the course of a year was seven times greater than stream Hg export, and over two times greater than wet bulk deposition to the boreal peatland. Measurements of dissolved gaseous Hg in the peat pore water also indicate Hg evasion. The net efflux may result from recent declines in atmospheric Hg concentrations that have turned the peatland from a net sink into a source of atmospheric Hg. This net Hg loss suggests that open boreal peatlands and downstream ecosystems can recover more rapidly from past atmospheric Hg deposition than previously assumed. This has important implications for future levels of methylmercury in boreal freshwater fish and the estimation of historical Hg accumulation rates from peat profiles.

Staphylococcus aureus aggregation and coagulation mechanisms, and their function in host-pathogen interactions

PubMed Central

Crosby, Heidi A.; Kwiecinski, Jakub; Horswill, Alexander R.

2017-01-01

The human commensal bacterium Staphylococcus aureus can cause a wide range of infections ranging from skin and soft tissue infections to invasive diseases like septicemia, endocarditis, and pneumonia. Muticellular organization almost certainly contributes to S. aureus pathogenesis mechanisms. While there has been considerable focus on biofilm formation and its role in colonizing prosthetic joints and indwelling devices, less attention has been paid to non-surface attached group behavior like aggregation and clumping. S. aureus is unique in its ability to coagulate blood, and it also produces multiple fibrinogen-binding proteins that facilitate clumping. Formation of clumps, which are large, tightly-packed groups of cells held together by fibrin(ogen), has been demonstrated to be important for S. aureus virulence and immune evasion. Clumps of cells are able to avoid detection by the host’s immune system due to a fibrin(ogen) coat that acts as a shield, and the size of the clumps facilitates evasion of phagocytosis. In addition, clumping could be an important early step in establishing infections that involve tight clusters of cells embedded in host matrix proteins, such as soft tissue abscesses and endocarditis. In this review we discuss clumping mechanisms and regulation, as well as what is known about how clumping contributes to immune evasion. PMID:27565579

F-15 HiDEC in flight over Mojave desert

NASA Technical Reports Server (NTRS)

1990-01-01

NASA's F-15 HIDEC (Highly Integrated Digital Electronic Control) research aircraft cruises over California's Mojave Desert at sunset on a flight out of the Dryden Flight Research Center, Edwards, California. The aircraft was used to carry out research on engine and flight control systems and most recently demonstrated the use of computer-assisted engine controls as a means of landing an aircraft safely with only engine power if its normal control surfaces such as elevators, rudders or ailerons are disabled. The aircraft also tested and evaluated a computerized self-repair flight control system for the Air Force that detects damaged or failed flight control surfaces, and then reconfigures undamaged flight surfaces so the mission can continue or the aircraft is landed safely. Nearly all research being carried out in the HIDEC program is applicable to future civilian and military aircraft.

Helicopter Flight Procedures for Community Noise Reduction

NASA Technical Reports Server (NTRS)

Greenwood, Eric

2017-01-01

A computationally efficient, semiempirical noise model suitable for maneuvering flight noise prediction is used to evaluate the community noise impact of practical variations on several helicopter flight procedures typical of normal operations. Turns, "quick-stops," approaches, climbs, and combinations of these maneuvers are assessed. Relatively small variations in flight procedures are shown to cause significant changes to Sound Exposure Levels over a wide area. Guidelines are developed for helicopter pilots intended to provide effective strategies for reducing the negative effects of helicopter noise on the community. Finally, direct optimization of flight trajectories is conducted to identify low noise optimal flight procedures and quantify the magnitude of community noise reductions that can be obtained through tailored helicopter flight procedures. Physically realizable optimal turns and approaches are identified that achieve global noise reductions of as much as 10 dBA Sound Exposure Level.

Spacelab

NASA Image and Video Library

1983-11-01

In this Spacelab-1 mission onboard photograph, astronaut Byron Lichtenberg performs a drop experiment, one of the Vestibular Experiments in Space investigations. The experiment examined spinal reflexes to determine whether they changed in microgravity. In Earth's environment, the otoliths signal the muscles to prepare for jolts associated with falling. During the flight, the normal reflex between the otoliths and the muscles was partially inhibited early in flight, declined further as the flight progressed, and returned to normal immediately after landing, suggesting that the brain ignored or reinterpreted otolith signals during space flight. Crewmembers reported a lack of awareness of position and location of feet, difficulty in maintaining balance, and a perception that falls were more sudden, faster, and harder than similar drops experienced in preflight. Crewmembers experienced illusions as they performed prescribed movement tests. When crew members viewed various targets and then pointed at them while blindfolded, their perception of target location and position of their own limbs was inaccurate in flight compared with similar tests on the ground. The Spacelab-1 was a multidisciplinary mission; that is, investigations were performed in several different fields of scientific research. The overall goal of the mission was to verify Spacelab performance through a variety of scientific experiments. The Spacelab-1 was launched aboard the Space Shuttle Orbiter Columbia for the STS-9 mission on November 28, 1983. The Marshall Space Flight Center had management responsibilities for the mission.

Manual flying of curved precision approaches to landing with electromechanical instrumentation. A piloted simulation study

NASA Technical Reports Server (NTRS)

Knox, Charles E.

1993-01-01

A piloted simulation study was conducted to examine the requirements for using electromechanical flight instrumentation to provide situation information and flight guidance for manually controlled flight along curved precision approach paths to a landing. Six pilots were used as test subjects. The data from these tests indicated that flight director guidance is required for the manually controlled flight of a jet transport airplane on curved approach paths. Acceptable path tracking performance was attained with each of the three situation information algorithms tested. Approach paths with both multiple sequential turns and short final path segments were evaluated. Pilot comments indicated that all the approach paths tested could be used in normal airline operations.

Verification and Validation of Adaptive and Intelligent Systems with Flight Test Results

NASA Technical Reports Server (NTRS)

Burken, John J.; Larson, Richard R.

2009-01-01

F-15 IFCS project goals are: a) Demonstrate Control Approaches that can Efficiently Optimize Aircraft Performance in both Normal and Failure Conditions [A] & [B] failures. b) Advance Neural Network-Based Flight Control Technology for New Aerospace Systems Designs with a Pilot in the Loop. Gen II objectives include; a) Implement and Fly a Direct Adaptive Neural Network Based Flight Controller; b) Demonstrate the Ability of the System to Adapt to Simulated System Failures: 1) Suppress Transients Associated with Failure; 2) Re-Establish Sufficient Control and Handling of Vehicle for Safe Recovery. c) Provide Flight Experience for Development of Verification and Validation Processes for Flight Critical Neural Network Software.

Spaceflight effects on cultured embryonic chick bone cells

NASA Technical Reports Server (NTRS)

Landis, W. J.; Hodgens, K. J.; Block, D.; Toma, C. D.; Gerstenfeld, L. C.

2000-01-01

A model calcifying system of primary osteoblast cell cultures derived from normal embryonic chicken calvaria has been flown aboard the shuttle, Endeavour, during the National Aeronautics and Space Administration (NASA) mission STS-59 (April 9-20, 1994) to characterize unloading and other spaceflight effects on the bone cells. Aliquots of cells (approximately 7 x 10(6)) grown in Dulbecco's modified Eagle's medium (DMEM) + 10% fetal bovine serum (FBS) were mixed with microcarrier beads, inoculated into cartridge culture units of artificial hollow fiber capillaries, and carried on the shuttle. To promote cell differentiation, cartridge media were supplemented with 12.5 microg/ml ascorbate and 10 mM beta-glycerophosphate for varying time periods before and during flight. Four cartridges contained cells from 17-day-old embryos grown for 5 days in the presence of ascorbate prior to launch (defined as flight cells committed to the osteoblastic lineage) and four cartridges supported cells from 14-day-old embryos grown for 10 days with ascorbate before launch (uncommitted flight cells). Eight cartridges prepared in the same manner were maintained under normal gravity throughout the flight (control cells) and four additional identical cartridges under normal gravity were terminated on the day of launch (basal cells). From shuttle launch to landing, all cartridges were contained in closed hardware units maintaining 5% CO2, 37 degrees C, and media delivery at a rate of approximately 1.5 ml/6 h. During day 3 and day 5 of flight, duplicate aliquots of conditioned media and accumulated cell products were collected in both the flight and the control hardware units. At the mission end, comparisons among flight, basal, and control samples were made in cell metabolism, gene expression for type I collagen and osteocalcin, and ultrastructure. Both committed and uncommitted flight cells were metabolically active, as measured by glucose uptake and lactate production, at approximately the same statistical levels as control counterparts. Flight cells elaborated a less extensive extracellular matrix, evidenced by a reduced collagen gene expression and collagen protein appearance compared with controls. Osteocalcin was expressed by all cells, a result indicating progressive differentiation of both flight and control osteoblasts, but its message levels also were reduced in flight cells compared with ground samples. This finding suggested that osteoblasts subjected to flight followed a slower progression toward a differentiated function. The summary of data indicates that spaceflight, including microgravity exposure, demonstrably affects bone cells by down-regulating type I collagen and osteocalcin gene expression and thereby inhibiting expression of the osteogenic phenotype notably by committed osteoblasts. The information is important for insight into the response of bone cells to changes of gravity and of force in general.

Simulating C fluxes along the terrestrial-aquatic continuum of the Amazon basin from 1861-2100

NASA Astrophysics Data System (ADS)

Lauerwald, R.; Regnier, P. A. G.; Ciais, P.

2017-12-01

To date, Earth System Models (ESM) ignore the lateral transfers of carbon (C) along the terrestrial-aquatic continuum down to the oceans and thus overestimate the terrestrial C storage. Here, we present the implementation of fluvial transport of dissolved organic carbon (DOC) and CO2 into ORCHIDEE, the land surface scheme of the Institut Pierre-Simon Laplace ESM. This new model branch, called ORCHILEAK, represents DOC production from canopy and soils, DOC and CO2 leaching from soils to streams, DOC decomposition and CO2 evasion to the atmosphere during its lateral transport in rivers, as well as exchange with the soil carbon and litter stocks in riparian wetlands. The model is calibrated and applied to the Amazon basin, including historical simulations starting from 1861 and future projections to the end of the 21st century. The model is found to reproduce well the observed dynamics in lateral DOC fluxes and CO2 evasion from the water surface. According to the simulations, half of the evading CO2 and 2/3 of the DOC transported in the rivers are produced within the water column or in flooded wetlands. We predict an increase in fluvial DOC exports to the coast and CO2 evasion to the atmosphere of about 1/4 over the 21st century (RCP 6.0). These long-term trends are mainly controlled by increasing atmospheric CO2 concentration and its fertilizing effect on terrestrial primary production in the model, while the effects of land-use change and increasing air temperature are minor. Interannual variations and seasonality of CO2 evasion and DOC transported by the river are however mainly controlled by hydrology. Over the simulation period, the actual land C sink represents less than half of the balance between terrestrial production and respiration in the Amazon basin, while the larger proportion is exported through the terrestrial-aquatic interface. These results highlight the importance of the terrestrial-aquatic continuum in the global C cycle.

Energetics and evasion dynamics of large predators and prey: pumas vs. hounds

PubMed Central

Wilmers, Christopher C.; Williams, Terrie M.

2017-01-01

Quantification of fine-scale movement, performance, and energetics of hunting by large carnivores is critical for understanding the physiological underpinnings of trophic interactions. This is particularly challenging for wide-ranging terrestrial canid and felid predators, which can each affect ecosystem structure through distinct hunting modes. To compare free-ranging pursuit and escape performance from group-hunting and solitary predators in unprecedented detail, we calibrated and deployed accelerometer-GPS collars during predator-prey chase sequences using packs of hound dogs (Canis lupus familiaris, 26 kg, n = 4–5 per chase) pursuing simultaneously instrumented solitary pumas (Puma concolor, 60 kg, n = 2). We then reconstructed chase paths, speed and turning angle profiles, and energy demands for hounds and pumas to examine performance and physiological constraints associated with cursorial and cryptic hunting modes, respectively. Interaction dynamics revealed how pumas successfully utilized terrain (e.g., fleeing up steep, wooded hillsides) as well as evasive maneuvers (e.g., jumping into trees, running in figure-8 patterns) to increase their escape distance from the overall faster hounds (avg. 2.3× faster). These adaptive strategies were essential to evasion in light of the mean 1.6× higher mass-specific energetic costs of the chase for pumas compared to hounds (mean: 0.76 vs. 1.29 kJ kg−1 min−1, respectively). On an instantaneous basis, escapes were more costly for pumas, requiring exercise at ≥90% of predicted \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\dot {\\mathrm{V }}{\\mathrm{O}}_{2\\mathrm{MAX}}$\\end{document}V ˙O2MAX and consuming as much energy per minute as approximately 5 min of active hunting. Our results demonstrate the marked investment of energy for evasion by a large, solitary carnivore and the advantage of dynamic maneuvers to postpone being overtaken by group-hunting canids. PMID:28828280

Seasonality of mercury in the Atlantic marine boundary layer

NASA Astrophysics Data System (ADS)

Soerensen, Anne L.; Sunderland, Elsie; Skov, Henrik; Holmes, Christopher; Jacob, Daniel J.

2010-05-01

Around one third of the mercury emissions today are from primary anthropogenic sources, with the remaining two-thirds from secondary reemissions of earlier deposition and natural sources (AMAP/UNEP 2008). Mercury exchange at the air-sea interface is important for the global distribution of atmospheric mercury as parts of deposited mercury will reenter the atmosphere through evasion. The exchange at the air-sea interface also affects the amount of inorganic mercury in the ocean and thereby the conversion to the neuro-toxic methylmercury. Here we combine new cruise measurements in the atmospheric marine boundary layer (MBL) of the Atlantic Ocean (Northern Hemisphere) from the fall of 2006 and the spring of 2007 with existing data from cruises in the Atlantic Ocean since 1978. We observe from these data a seasonal cycle in Hg(0) concentrations in the Atlantic marine boundary later (MBL) that exhibits minimum concentrations during summer and high concentrations during fall to spring. These observations suggest a local, seasonally dependent Hg(0) source in the MBL that causes variability in concentrations above the open ocean. To further investigate controls on Hg(0) concentrations in the MBL, we developed an improved representation of oceanic air-sea exchange processes within the GEOS-Chem global 3-D biogeochemical mercury model. Specifically, we used new data on mercury redox reactions in the surface ocean as a function of biological and photochemical processes, and implemented new algorithms for mercury dynamics associated with suspended particles. Our coupled atmospheric-oceanic modeling results support the premise that oceanic evasion is a main driver controlling Hg(0) concentrations in the MBL. We also use the model to investigate what drivers the evasion across the air-sea interface on shorter timescales. This is done by tracking evasion rates and other model components on an hourly basis for chosen locations in the Atlantic Ocean.

The sea-air exchange of mercury (Hg) in the marine boundary layer of the Augusta basin (southern Italy): concentrations and evasion flux.

PubMed

Bagnato, E; Sproveri, M; Barra, M; Bitetto, M; Bonsignore, M; Calabrese, S; Di Stefano, V; Oliveri, E; Parello, F; Mazzola, S

2013-11-01

The first attempt to systematically investigate the atmospheric mercury (Hg) in the MBL of the Augusta basin (SE Sicily, Italy) has been undertaken. In the past the basin was the receptor for Hg from an intense industrial activity which contaminated the bottom sediments of the Bay, making this area a potential source of pollution for the surrounding Mediterranean. Three oceanographic cruises have been thus performed in the basin during the winter and summer 2011/2012, where we estimated averaged Hgatm concentrations of about 1.5±0.4 (range 0.9-3.1) and 2.1±0.98 (range 1.1-3.1) ng m(-3) for the two seasons, respectively. These data are somewhat higher than the background Hg atm value measured over the land (range 1.1±0.3 ng m(-3)) at downtown Augusta, while are similar to those detected in other polluted regions elsewhere. Hg evasion fluxes estimated at the sea/air interface over the Bay range from 3.6±0.3 (unpolluted site) to 72±0.1 (polluted site of the basin) ng m(-2) h(-1). By extending these measurements to the entire area of the Augusta basin (~23.5 km(2)), we calculated a total sea-air Hg evasion flux of about 9.7±0.1 g d(-1) (~0.004 tyr(-1)), accounting for ~0.0002% of the global Hg oceanic evasion (2000 tyr(-1)). The new proposed data set offers a unique and original study on the potential outflow of Hg from the sea-air interface at the basin, and it represents an important step for a better comprehension of the processes occurring in the marine biogeochemical cycle of this element. Copyright © 2013 Elsevier Ltd. All rights reserved.

Human muscle sympathetic nerve activity and plasma noradrenaline kinetics in space

PubMed Central

Ertl, Andrew C; Diedrich, André; Biaggioni, Italo; Levine, Benjamin D; Robertson, Rose Marie; Cox, James F; Zuckerman, Julie H; Pawelczyk, James A; Ray, Chester A; Buckey, Jay C; Lane, Lynda D; Shiavi, Richard; Gaffney, F Andrew; Costa, Fernando; Holt, Carol; Blomqvist, C Gunnar; Eckberg, Dwain L; Baisch, Friedhelm J; Robertson, David

2002-01-01

Astronauts returning from space have reduced red blood cell masses, hypovolaemia and orthostatic intolerance, marked by greater cardio–acceleration during standing than before spaceflight, and in some, orthostatic hypotension and presyncope. Adaptation of the sympathetic nervous system occurring during spaceflight may be responsible for these postflight alterations. We tested the hypotheses that exposure to microgravity reduces sympathetic neural outflow and impairs sympathetic neural responses to orthostatic stress. We measured heart rate, photoplethysmographic finger arterial pressure, peroneal nerve muscle sympathetic activity and plasma noradrenaline spillover and clearance, in male astronauts before, during (flight day 12 or 13) and after the 16 day Neurolab space shuttle mission. Measurements were made during supine rest and orthostatic stress, as simulated on Earth and in space by 7 min periods of 15 and 30 mmHg lower body suction. Mean (± s.e.m.) heart rates before lower body suction were similar pre–flight and in flight. Heart rate responses to −30 mmHg were greater in flight (from 56 ± 4 to 72 ± 4 beats min−1) than pre–flight (from 56 ± 4 at rest to 62 ± 4 beats min−1, P < 0.05). Noradrenaline spillover and clearance were increased from pre–flight levels during baseline periods and during lower body suction, both in flight (n = 3) and on post–flight days 1 or 2 (n = 5, P < 0.05). In–flight baseline sympathetic nerve activity was increased above pre–flight levels (by 10–33 %) in the same three subjects in whom noradrenaline spillover and clearance were increased. The sympathetic response to 30 mmHg lower body suction was at pre–flight levels or higher in each subject (35 pre–flight vs. 40 bursts min−1 in flight). No astronaut experienced presyncope during lower body suction in space (or during upright tilt following the Neurolab mission). We conclude that in space, baseline sympathetic neural outflow is increased moderately and sympathetic responses to lower body suction are exaggerated. Therefore, notwithstanding hypovolaemia, astronauts respond normally to simulated orthostatic stress and are able to maintain their arterial pressures at normal levels. PMID:11773339

Human muscle sympathetic nerve activity and plasma noradrenaline kinetics in space

NASA Technical Reports Server (NTRS)

Ertl, Andrew C.; Diedrich, Andre; Biaggioni, Italo; Levine, Benjamin D.; Robertson, Rose Marie; Cox, James F.; Zuckerman, Julie H.; Pawelczyk, James A.; Ray, Chester A.; Buckey, Jay C Jr;

Quality control method to measure predator evasion in wild and mass-reared Mediterranean fruit flies (Diptera: Tephritidae)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hendrichs, M.; Wornoayporn, V.; Hendrichs, J.

Sterile male insects, mass-reared and released as part of sterile insect technique (SIT) programs, must survive long enough in the field to mature sexually and compete effectively with wild males for wild females. An often reported problem in Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann) SIT programs is that numbers of released sterile males decrease rapidly in the field for various reasons, including losses to different types of predators. This is a serious issue in view that most operational programs release sterile flies at an age when they are still immature. Previous field and field-cage tests have confirmed that fliesmore » of laboratory strains are less able to evade predators than wild flies. Such tests involve, however, considerable manipulation and observation of predators and are therefore not suitable for routine measurements of predator evasion. Here we describe a simple quality control method with aspirators to measure agility in medflies and show that this parameter is related to the capacity of flies to evade predators. Although further standardization of the test is necessary to allow more accurate inter-strain comparisons, results confirm the relevance of measuring predator evasion in mass-reared medfly strains. Besides being a measure of this sterile male quality parameter, the described method could be used for the systematic selection of strains with a higher capacity for predator evasion. (author) [Spanish] Insectos machos esteriles criados en forma masiva para ser liberados en programas que utilizan la tecnica del insecto esteril (TIE), tienen que tener la capacidad de sobrevivir en el campo el tiempo necesario para poder madurar sexualmente y competir efectivamente con los machos silvestres por hembras silvestres. Un problema frecuentemente reportado por dichos programas de la mosca del Mediterraneo, Ceratitis capitata (Wiedemann), es que el numero de machos esteriles de laboratorio liberados en el campo, decrecen rapidamente por varias razones, incluyendo perdidas debidas a diferentes tipos de depredadores. Estudios anteriores conducidos en el campo, y en jaulas de campo, han confirmado que las cepas de machos de laboratorio tienen menos capacidad de evadir depredadores que los machos silvestres. Estos estudios involucran, sin embargo, una considerable cantidad de manipulacion y observacion de depredadores, por lo que no son adecuados para ser usados como medidas rutinarias en los programas de cria masiva. Aqui describimos un metodo sencillo de control de calidad usando aspiradores para medir agilidad en la mosca del Mediterraneo y mostramos que este parametro esta relacionado a la capacidad de la moscas a evadir a depredadores. Aunque aun es necesario refinar la estandarizacion de este metodo para permitir la comparacion entre cepas, los resultados confirman la importancia de tener un metodo rutinario para medir la capacidad de evasion de depredadores en cepas de cria de laboratorio de la mosca del Mediterraneo. Ademas de medir este parametro de control de calidad de los machos esteriles, el metodo descrito podria tambien ser usado para la seleccion sistematica de cepas con una mayor capacidad de evasion de depredadores. (author)« less

Ground Taxi Navigation Problems and Training Solutions

NASA Technical Reports Server (NTRS)

Quinn, Cheryl; Walter, Kim E.; Rosekind, Mark (Technical Monitor)

1997-01-01

Adverse weather conditions can put considerable strain on the National Airspace System. Even small decreases in visibility on the airport surface can create delays, hinder safe movement and lead to errors. Studies of Aviation Safety Reporting System (ASRS) surface movement incidents support the need for technologies and procedures to improve ground operations in low-visibility conditions. This study examined 139 ASRS reports of low-visibility surface movement incidents at 10 major U.S. airports. Errors were characterized in terms of incident type, contributing factors and consequences. The incidents in the present sample were comprised of runway transgressions, taxiway excursions and ground conflicts. The primary contributing factors were Airport Layout and Markings, Communication and Distraction. In half the incidents the controller issued a new clearance or the flight crew took an evasive action and in the remaining half, no recovery attempt was made because the error was detected after the fact. By gaining a better understanding the factors that affect crew navigation in low visibility and the types of errors that are likely to occur, it will be possible to develop more robust technologies to aid pilots in the ground taxi task. Implications for crew training and procedure development for low-visibility ground taxi are also discussed.

14 CFR 125.327 - Briefing of passengers before flight.

Code of Federal Regulations, 2010 CFR

2010-01-01

... flotation equipment; (7) If the flight involves operations above 12,000 feet MSL, the normal and emergency... expeditiously to an exit if an emergency occurs and that person's attendant, if any, has received a briefing as... the crew. It shall be supplemented by printed cards for the use of each passenger containing— (1) A...

14 CFR 125.327 - Briefing of passengers before flight.

Code of Federal Regulations, 2013 CFR

2013-01-01

... flotation equipment; (7) If the flight involves operations above 12,000 feet MSL, the normal and emergency... expeditiously to an exit if an emergency occurs and that person's attendant, if any, has received a briefing as... the crew. It shall be supplemented by printed cards for the use of each passenger containing— (1) A...

14 CFR 125.327 - Briefing of passengers before flight.

Code of Federal Regulations, 2011 CFR

2011-01-01

... flotation equipment; (7) If the flight involves operations above 12,000 feet MSL, the normal and emergency... expeditiously to an exit if an emergency occurs and that person's attendant, if any, has received a briefing as... the crew. It shall be supplemented by printed cards for the use of each passenger containing— (1) A...

14 CFR 125.327 - Briefing of passengers before flight.

Code of Federal Regulations, 2014 CFR

2014-01-01

... flotation equipment; (7) If the flight involves operations above 12,000 feet MSL, the normal and emergency... expeditiously to an exit if an emergency occurs and that person's attendant, if any, has received a briefing as... the crew. It shall be supplemented by printed cards for the use of each passenger containing— (1) A...

14 CFR 125.327 - Briefing of passengers before flight.

Code of Federal Regulations, 2012 CFR

2012-01-01

... flotation equipment; (7) If the flight involves operations above 12,000 feet MSL, the normal and emergency... expeditiously to an exit if an emergency occurs and that person's attendant, if any, has received a briefing as... the crew. It shall be supplemented by printed cards for the use of each passenger containing— (1) A...

Cytological and ultrastructural studies on root tissues

NASA Technical Reports Server (NTRS)

Slocum, R. D.; Gaynor, J. J.; Galston, A. W.

1984-01-01

The anatomy and fine structure of roots from oat and mung bean seedlings, grown under microgravity conditions for 8 days aboard the Space Shuttle, was examined and compared to that of roots from ground control plants grown under similar conditions. Roots from both sets of oat seedlings exhibited characteristic monocotyledonous tissue organization and normal ultrastructural features, except for cortex cell mitochondria, which exhibited a 'swollen' morphology. Various stages of cell division were observed in the meristematic tissues of oat roots. Ground control and flight-grown mung bean roots also showed normal tissue organization, but root cap cells in the flight-grown roots were collapsed and degraded in appearance, especially at the cap periphery. At the ultrastructural level, these cells exhibited a loss of organelle integrity and a highly-condensed cytoplasm. This latter observation perhaps suggests a differing tissue sensitivity for the two species to growth conditions employed in space flight. The basis for abnormal root cap cell development is not understood, but the loss of these putative gravity-sensing cells holds potential significance for long term plant growth orientation during space flight.

Nonlinear Unsteady Aerodynamic Modeling Using Wind Tunnel and Computational Data

NASA Technical Reports Server (NTRS)

Murphy, Patrick C.; Klein, Vladislav; Frink, Neal T.

2016-01-01

Extensions to conventional aircraft aerodynamic models are required to adequately predict responses when nonlinear unsteady flight regimes are encountered, especially at high incidence angles and under maneuvering conditions. For a number of reasons, such as loss of control, both military and civilian aircraft may extend beyond normal and benign aerodynamic flight conditions. In addition, military applications may require controlled flight beyond the normal envelope, and civilian flight may require adequate recovery or prevention methods from these adverse conditions. These requirements have led to the development of more general aerodynamic modeling methods and provided impetus for researchers to improve both techniques and the degree of collaboration between analytical and experimental research efforts. In addition to more general mathematical model structures, dynamic test methods have been designed to provide sufficient information to allow model identification. This paper summarizes research to develop a modeling methodology appropriate for modeling aircraft aerodynamics that include nonlinear unsteady behaviors using both experimental and computational test methods. This work was done at Langley Research Center, primarily under the NASA Aviation Safety Program, to address aircraft loss of control, prevention, and recovery aerodynamics.

Pigeons trade efficiency for stability in response to level of challenge during confined flight.

PubMed

Williams, C David; Biewener, Andrew A

2015-03-17

Individuals traversing challenging obstacles are faced with a decision: they can adopt traversal strategies that minimally disrupt their normal locomotion patterns or they can adopt strategies that substantially alter their gait, conferring new advantages and disadvantages. We flew pigeons (Columba livia) through an array of vertical obstacles in a flight arena, presenting them with this choice. The pigeons selected either a strategy involving only a slight pause in the normal wing beat cycle, or a wings-folded posture granting reduced efficiency but greater stability should a misjudgment lead to collision. The more stable but less efficient flight strategy was not used to traverse easy obstacles with wide gaps for passage but came to dominate the postures used as obstacle challenge increased with narrower gaps and there was a greater chance of a collision. These results indicate that birds weigh potential obstacle negotiation strategies and estimate task difficulty during locomotor pattern selection.

Pigeons trade efficiency for stability in response to level of challenge during confined flight

PubMed Central

Williams, C. David; Biewener, Andrew A.

2015-01-01

Individuals traversing challenging obstacles are faced with a decision: they can adopt traversal strategies that minimally disrupt their normal locomotion patterns or they can adopt strategies that substantially alter their gait, conferring new advantages and disadvantages. We flew pigeons (Columba livia) through an array of vertical obstacles in a flight arena, presenting them with this choice. The pigeons selected either a strategy involving only a slight pause in the normal wing beat cycle, or a wings-folded posture granting reduced efficiency but greater stability should a misjudgment lead to collision. The more stable but less efficient flight strategy was not used to traverse easy obstacles with wide gaps for passage but came to dominate the postures used as obstacle challenge increased with narrower gaps and there was a greater chance of a collision. These results indicate that birds weigh potential obstacle negotiation strategies and estimate task difficulty during locomotor pattern selection. PMID:25733863

Going Below Minimums: The Efficacy of Display Enhanced/Synthetic Vision Fusion for Go-Around Decisions during Non-Normal Operations

NASA Technical Reports Server (NTRS)

Prinzel, Lawrence J., III; Kramer, Lynda J.; Bailey, Randall E.

2007-01-01

The use of enhanced vision systems in civil aircraft is projected to increase rapidly as the Federal Aviation Administration recently changed the aircraft operating rules under Part 91, revising the flight visibility requirements for conducting approach and landing operations. Operators conducting straight-in instrument approach procedures may now operate below the published approach minimums when using an approved enhanced flight vision system that shows the required visual references on the pilot's Head-Up Display. An experiment was conducted to evaluate the complementary use of synthetic vision systems and enhanced vision system technologies, focusing on new techniques for integration and/or fusion of synthetic and enhanced vision technologies and crew resource management while operating under these newly adopted rules. Experimental results specific to flight crew response to non-normal events using the fused synthetic/enhanced vision system are presented.

The Pressure Distribution over the Wings and Tail Surfaces of a PW-9 Pursuit Airplane in Flight

NASA Technical Reports Server (NTRS)

Rhode, Richard

1931-01-01

This report presents the results of an investigation to determine (1) the magnitude and distribution of aerodynamic loads over the wings and tail surfaces of a pursuit-type airplane in the maneuvers likely to impose critical loads on the various subassemblies of the airplane structure. (2) To study the phenomenon of center of pressure movement and normal force coefficient variation in accelerated flight, and (3) to measure the normal accelerations at the center of gravity, wing-tip, and tail, in order to determine the nature of the inertia forces acting simultaneously with the critical aerodynamic loads. The results obtained throw light on a number of important questions involving structural design. Some of the more interesting results are discussed in some detail, but in general the report is for the purpose of making this collection of airplane-load data obtained in flight available to those interested in airplane structures.

Impact of Vehicle Flexibility on IRVE-II Flight Dynamics

NASA Technical Reports Server (NTRS)

Bose, David M.; Toniolo, Matthew D.; Cheatwood, F. M.; Hughes, Stephen J.; Dillman, Robert A.

2011-01-01

The Inflatable Re-entry Vehicle Experiment II (IRVE-II) successfully launched from Wallops Flight Facility (WFF) on August 17, 2009. The primary objectives of this flight test were to demonstrate inflation and re-entry survivability, assess the thermal and drag performance of the reentry vehicle, and to collect flight data for refining pre-flight design and analysis tools. Post-flight analysis including trajectory reconstruction outlined in O Keefe3 demonstrated that the IRVE-II Research Vehicle (RV) met mission objectives but also identified a few anomalies of interest to flight dynamics engineers. Most notable of these anomalies was high normal acceleration during the re-entry pressure pulse. Deflection of the inflatable aeroshell during the pressure pulse was evident in flight video and identified as the likely cause of the anomaly. This paper provides a summary of further post-flight analysis with particular attention to the impact of aeroshell flexibility on flight dynamics and the reconciliation of flight performance with pre-flight models. Independent methods for estimating the magnitude of the deflection of the aeroshell experienced on IRVE-II are discussed. The use of the results to refine models for pre-flight prediction of vehicle performance is then described.

Red blood cell and iron metabolism during space flight

NASA Technical Reports Server (NTRS)

Smith, Scott M.

2002-01-01

Space flight anemia is a widely recognized phenomenon in astronauts. Reduction in circulating red blood cells and plasma volume results in a 10% to 15% decrement in circulatory volume. This effect appears to be a normal physiologic adaptation to weightlessness and results from the removal of newly released blood cells from the circulation. Iron availability increases, and (in the few subjects studied) iron stores increase during long-duration space flight. The consequences of these changes are not fully understood.

Effects of spaceflight on the spermatogonial population of rat seminiferous epithelium

NASA Technical Reports Server (NTRS)

Sapp, Walter J.; Philpott, Delbert E.; Williams, Carol S.; Kato, Katharine; Stevenson, Joann; Vasquez, M.; Serova, L. V.

1990-01-01

Testes from rats flown on Cosmos 1887 were compared with vivarium control and synchronous control samples. The mean weights of flight testes, normalized for weight per 100 g, were 6.4 percent less when compared with the vivarium controls. Counts of spermatogonia from tissue sections (seminiferous tubules in maturation stage 6) from five animals in each group revealed 4 percent fewer spermatogonia in flight testes compared with synchronous controls and 11 percent fewer spermatogonia in flight samples compared with vivarium controls.

Flight experience with manually controlled unconventional aircraft motions

NASA Technical Reports Server (NTRS)

Barfield, A. F.

1978-01-01

A modified YF-16 aircraft was used to flight demonstrate decoupled modes under the USAF Fighter Control Configured Vehicle (CCV) Program. The direct force capabilities were used to implement seven manually controlled unconventional modes on the aircraft, allowing flat turns, decoupled normal acceleration control, independent longitudinal and lateral translations, uncoupled elevation and azimuth aiming, and blended direct lift. This paper describes the design, development, and flight testing of these control modes. The need for task-tailored mode authorities, gain-scheduling and selected closed-loop design is discussed.

Differential games in economic systems with delays

NASA Astrophysics Data System (ADS)

Kim, A. V.; Kormyshev, V. M.; Novikov, M. Yu.; Nikonov, M. A.

2017-11-01

In the paper, we consider application of i-smooth analysis (A.V. Kim, 2015) to differential games with delays in economics (Dockner E.J., et all, 2000; R. Isaacs, 1999). The approach is developed in the framework of the theory of positional differential games (N.N. Krasovskii, A.I. Subbotin, 1988; A.V. Kryazhimskii, Yu.S. Osipov, 1973; Yu.S. Osipov, J. Appl. Math. Mech. Vol. 35, № 1, № 6, 1971) and is based on application of the extremal shift strategy. We consider basic notions and constructions of the approach-evasion problem for linear systems with delays. The necessary and sufficient conditions of solvability the approach-evasion problem in terms of special u-stable sets are presented in another paper.

Dynamics of tax evasion through an epidemic-like model

NASA Astrophysics Data System (ADS)

Brum, Rafael M.; Crokidakis, Nuno

In this work, we study a model of tax evasion. We considered a fixed population divided in three compartments, namely honest tax payers, tax evaders and a third class between the mentioned two, which we call susceptibles to become evaders. The transitions among those compartments are ruled by probabilities, similarly to a model of epidemic spreading. These probabilities model social interactions among the individuals, as well as the government’s fiscalization. We simulate the model on fully-connected graphs, as well as on scale-free and random complex networks. For the fully-connected and random graph cases, we observe that the emergence of tax evaders in the population is associated with an active-absorbing nonequilibrium phase transition, that is absent in scale-free networks.